JP2002372472A - Apparatus and method for detection of physical quantity using optical fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a physical-quantity detection apparatus by which a physical quantity can be measured with high accuracy by compensating the influence of the temperature of a physical-quantity detection sensor. SOLUTION: Emitted light by a light emitting element 2 whose temperature is controlled doubly by a light emitting element module 1 and a temperature holding fixture 8 is branched, by a first optical fiber coupler 13, into an optical fiber 12 for signal light and an optical fiber 16 for reference light, a signal light part 15a in the physical-quantity detection sensor 15 is irradiated with the emitted light guided to the optical fiber 12, and its reflected light is converted into a measuring signal by a photodetector 17 for signal detection via the optical fiber 12 and the coupler 13. A reference light part 15b in the sensor 15 is irradiated via a second optical fiber coupler 19 with the emitted light branched into the optical fiber 16, and its reflected light is converted into a reference signal via the coupler 19.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention compensates for a change in zero point and a change in sensitivity, which are the effects of temperature, when converting an optical signal from a physical quantity sensor using an optical fiber into a signal corresponding to a physical quantity. The present invention relates to a physical quantity detection device and a physical quantity detection method using an optical fiber that can accurately measure a physical quantity.

[0002]

2. Description of the Related Art In a conventional optical fiber pressure sensor having such a temperature compensating function, a signal light section for obtaining a signal light corresponding to a pressure on a diaphragm section deformed by pressure, and a reference for obtaining a reference signal. An optical section is provided on the diaphragm, and an optical fiber for signal light is disposed with a gap in opposition to the signal optical section of the diaphragm. There is known a device that irradiates a reference beam through a reference beam optical fiber. In such an optical fiber pressure sensor, when the signal light portion is displaced in accordance with the pressure applied to the diaphragm and the gap between the signal light portion and the signal light optical fiber is changed in accordance with the amount of displacement, the signal light portion is changed in accordance with the change amount. Thus, the signal light radiated from the emission end of the signal light optical fiber to the signal light portion is reflected by the signal light portion, and the intensity of the signal light incident on the signal light optical fiber changes. This signal light is converted into an electric signal by a signal light detector to obtain a measurement signal.

The gap between the reference light section and the reference light optical fiber is kept constant irrespective of the pressure, although it depends on the temperature. The reference beam is irradiated with the reference beam through the reference beam optical fiber, the reflected beam is received by the reference beam optical fiber, and the reference beam is converted into an electric signal by the reference signal detector to obtain the reference signal. I have. Based on the measurement signal and the reference signal obtained in this way, a measurement signal in which the influence of temperature is minimized is obtained. As a specific example of the conventional temperature correction mechanism of a pressure sensor using an optical fiber, for example, there is a "method of temperature compensation of an optical fiber pressure sensor system" disclosed in Japanese Patent Application Laid-Open No. 8-62080. .

In the case of the diaphragm reflection type optical fiber pressure sensor described in the above-mentioned Japanese Patent Application Laid-Open No. 8-62080,
A pressure-measuring optical fiber, a pressure-receiving diaphragm for reflecting light emitted from the pressure-measuring optical fiber and receiving the light by the pressure-measuring optical fiber, and a temperature correcting light provided in parallel with the pressure-measuring optical fiber. A fiber, and a reflecting surface member for reflecting light emitted from the temperature correcting optical fiber and receiving the light on the temperature correcting optical fiber. The reflecting surface member is positioned at a position corresponding to the pressure receiving diaphragm, and the pressure of the gas to be measured is set. When the pressure-receiving diaphragm is not deformed from the emission end of the pressure-measuring optical fiber from the emission end of the temperature-measuring optical fiber to the reflecting surface of the reflecting surface body. It is equal to the distance to the inner surface, the temperature compensating optical fiber is completely unaffected by the pressure of the fluid to be measured, and the pressure measuring fiber, Since the optical fiber for temperature correction is affected by exactly the same condition with respect to thermal expansion, the change in the optical path length of the optical fiber for pressure measurement due to thermal expansion simply corresponds to the change in the optical path length of the optical fiber for temperature correction itself. A configuration and a method of removing an error due to the influence of temperature by subtracting a change in the light intensity signal are employed.

[0005]

However, the temperature correction that can be removed by the method described in the above-mentioned Japanese Patent Application Laid-Open No. 8-62080 is the temperature effect of the zero point where no pressure is applied, and depends on the temperature of the material of the diaphragm. It is not possible to compensate for the temperature effect of pressure sensitivity due to the change in Young's modulus.
In addition, there is a type in which the temperature of the light source is controlled to be constant and a light intensity to be incident on the optical fiber is controlled to be constant, that is, a type having a built-in auto power control function. There was nothing to control the temperature of the related optical components constantly.
Further, there was no pressure sensor measurement system capable of performing temperature compensation in total. Therefore, in the system described in the above publication, the temperature effect as a whole of the pressure sensor measurement system, that is, the change of the zero point and the change of the sensitivity cannot be compensated, and the pressure cannot be measured with high accuracy. There was a problem.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and compensates for temperature effects such as a change in zero point and a change in sensitivity of a physical quantity detection sensor as a whole, thereby enabling highly accurate physical quantity measurement. It is an object of the present invention to provide a physical quantity detection device and a physical quantity detection method using a fiber. An object of claim 1 of the present invention is to make it possible to control the temperature so as to keep the temperature of the optical component constant, thereby stabilizing the output of the light emitting element as a light source and reducing the amount of light incident on the physical quantity detection sensor. And stabilize the detection sensitivity by removing the temperature effects of the optical components.In addition, it compensates for temperature effects such as changes in the zero point and changes in the sensitivity of the physical quantity detection sensor as a whole, resulting in high accuracy. It is an object of the present invention to provide a physical quantity detection device using an optical fiber capable of realizing accurate physical quantity measurement. A second object of the present invention is to provide a physical quantity detection device using an optical fiber capable of realizing more accurate physical quantity measurement, in addition to the object of the first aspect. An object of a third aspect of the present invention is to provide a physical quantity detection device using an optical fiber which can maintain a constant temperature of a light emitting element module and emit light stably.

[0007] It is an object of the present invention that the optical component attached to the optical component temperature holding attachment member can be kept at the second temperature, and the optical component can operate stably without being affected by the temperature. It is an object of the present invention to provide a physical quantity detection device using an optical fiber, which can surely compensate for the temperature influence of the physical quantity detection sensor and enable highly accurate physical quantity measurement. An object of claim 5 of the present invention is to provide an optical fiber which can perform automatic power control of a light emitting element and enable more stable light emission in combination with the light emitting element module being kept at a constant temperature. An object of the present invention is to provide a used physical quantity detection device. An object of a sixth aspect of the present invention is to provide a physical quantity detection device using an optical fiber that can accurately measure the pressure of a fluid or the like. An object of claim 7 of the present invention is to provide a light detector for signal detection, a reference signal detector, and the like. Light detector,
Eliminates the effect of temperature on the optical detector for driver signals, stabilizes the detection sensitivity, compensates for both the zero point and temperature sensitivity of the physical quantity detection sensor, and measures the physical quantity for high temperatures by taking advantage of the heat resistance that is an advantage of optical fibers. It is an object of the present invention to provide a physical quantity detection device using an optical fiber that can be applied to a system and that can calculate a measured physical quantity with a required calculation accuracy.

[0008] It is an object of the present invention that the output of a light emitting element as a light source and the temperature of an optical component can be kept constant, the amount of incident light of a physical quantity detection sensor can be stabilized, and a photodetector for signal detection. The temperature sensitivity of the reference signal photodetector and the driver signal photodetector can be removed to keep the detection sensitivity constant, and both the zero point and temperature sensitivity of the physical quantity detection sensor can be compensated. An object of the present invention is to provide a physical quantity detection device using an optical fiber, which can be applied to a physical quantity measurement system for high temperature utilizing the optical fiber and can calculate the measured physical quantity at high speed and with required calculation accuracy. In particular, an object of the present invention is to keep the output of a light emitting element as a light source and the temperature of an optical component constant, to stabilize the amount of incident light on a physical quantity detection sensor, to use a photodetector for signal detection and a reference signal. The temperature sensitivity of the photodetector for sensor and the driver signal can be removed to keep the detection sensitivity constant, and both the zero point and temperature sensitivity of the physical quantity detection sensor can be compensated. An object of the present invention is to provide a physical quantity detection method using an optical fiber that can be applied to a high-temperature physical quantity measurement system. An object of a tenth aspect of the present invention is to provide a physical quantity detection device using an optical fiber capable of obtaining a signal corresponding to a physical quantity accurately while minimizing the influence of bending of the optical fiber. An object of claim 11 of the present invention is to provide a physical quantity detection device using an optical fiber which can obtain a signal accurately corresponding to a physical quantity while minimizing the influence of bending of the optical fiber.

[0009]

According to the first aspect of the present invention, there is provided a physical quantity detecting device using an optical fiber according to the present invention, wherein a light emitting element and a heat absorbing or heat generating element for the light emitting element are provided. A physical quantity detection sensor including a light emitting element module having a first Peltier element acting thereon and maintaining a predetermined first temperature, a signal light section displaced in accordance with a physical quantity, and a reference light section not displaced in accordance with the physical quantity; An emission end is arranged with a gap facing the signal light portion of the physical quantity detection sensor, guides light emitted from the light emitting element to irradiate the signal light portion, and emits light from the signal light portion. An optical fiber for signal light, which receives and guides reflected light,
An emission end is arranged at a predetermined distance from the reference light portion of the physical quantity detection sensor, guides emitted light of the light emitting element to irradiate the reference light portion, and reflects light from the reference light portion. The reference light optical fiber that is incident and guided, and the light emitted from the light emitting element is branched into the signal light optical fiber and the reference light optical fiber, and is guided by the signal light optical fiber. A first optical fiber coupler that guides the reflected light from the signal light unit; and a light emission device that guides light emitted from the light emitting element branched by the first optical fiber coupler to the reference light optical fiber and emits the light. A second optical fiber coupler that branches off as a driver for the element and guides reflected light from the reference light section guided by the reference light optical fiber; and a second optical fiber coupler guided by the first optical fiber coupler. Anti-reflection from the signal light section A signal detection photodetector that receives light and converts it into a measurement signal corresponding to the physical quantity; and a displacement due to thermal expansion of the reference light section due to a temperature change amount applied to the physical quantity detection sensor and the reference light optical fiber. A reference signal light detector that receives reflected light corresponding to the reference light via the reference light optical fiber and the second optical fiber coupler and converts the reflected light into a reference signal; A driver signal light detector for receiving light emitted from the light emitting element branched for a driver and converting the light into a driver signal for the light emitting element, the light emitting element module, the first optical fiber coupler, and the second optical fiber coupler Optical components such as the signal detection photodetector, the reference signal photodetector, and the driver signal photodetector are mounted, and a second Peltier element is used to maintain a predetermined second temperature. It is characterized by comprising a securing member for optical component temperature holding, the for.

According to a second aspect of the present invention, there is provided a physical quantity detecting device using an optical fiber according to the present invention. A physical quantity detection sensor having a light emitting element module for maintaining a temperature, a signal light section displaced according to a physical quantity, and a reference light section not displaced with respect to the physical quantity, and a gap facing the signal light section of the physical quantity detection sensor An emission end is disposed at a distance, and the signal light optical fiber guides the emitted light of the light emitting element to irradiate the signal light portion, and receives and guides the reflected light from the signal light portion. An emission end is arranged at a predetermined distance from the reference light unit of the physical quantity detection sensor, guides light emitted from the light emitting element to irradiate the reference light unit, and reflects the light from the reference light unit. Light incident An optical fiber for a reference light to be waved, a first optical fiber coupler for branching the light emitted from the light emitting element to the optical fiber for a signal light and the optical fiber for the reference light, and the first optical fiber coupler branched by the first optical fiber coupler. A second optical fiber coupler that guides light emitted from the light emitting element to the signal light optical fiber and guides reflected light from the signal light portion guided by the signal light optical fiber; The emitted light of the light emitting element branched by the optical fiber coupler is guided to the reference light optical fiber, and the light is branched for a driver of the light emitting element, and the reference light guided by the reference light optical fiber. A third optical fiber coupler that guides the reflected light from the optical unit; and a reflected light from the signal light unit that is guided by the second optical fiber coupler and converts the received light into a measurement signal corresponding to the physical quantity. The signal detection photodetector, the reflected light corresponding to the displacement due to the thermal expansion of the reference light portion due to the temperature change applied to the physical quantity detection sensor and the reference light optical fiber, and the reference light optical fiber and the A reference signal photodetector for receiving light via a three optical fiber coupler and converting it into a reference signal; and receiving light emitted from the light emitting element branched for a driver of the light emitting element by the third optical fiber coupler. A photodetector for a driver signal for converting the signal to a driver signal for the light emitting element, the light emitting element module, the first optical fiber coupler, the second optical fiber coupler, the third optical fiber coupler, and the signal detection light detection. Optical components for holding a predetermined second temperature by a second Peltier element by mounting optical components such as a detector, the above-mentioned reference signal photodetector, and the above-mentioned driver signal photodetector. And a mounting member.

According to a third aspect of the present invention, in the physical quantity detecting device using an optical fiber according to the present invention, the light emitting element module is controlled by a first temperature controller based on a temperature detected by a first temperature sensor provided therein. The first temperature is maintained at the first temperature by controlling the first Peltier element. In the physical quantity detection device using an optical fiber according to the present invention, the optical component attached to the optical component temperature holding attachment member is detected by a second temperature sensor provided at a predetermined position. The second temperature is controlled at a second temperature by controlling the second Peltier element by a second temperature controller based on the temperature. In the physical quantity detecting device using an optical fiber according to the present invention, the light emitting element automatically controls power by a light emitting element driver based on a driver signal of the light emitting element converted by the driver signal light detector. And emits light with a constant light amount. 7. The physical quantity detection device using an optical fiber according to the present invention according to claim 6, wherein the physical quantity detection sensor is a pressure sensor, and a diaphragm portion facing an emission end of the signal light optical fiber; and the reference light. And a rigid body portion facing the optical fiber.

According to a seventh aspect of the present invention, a physical quantity detecting device using an optical fiber according to the present invention includes a light emitting element and a first Peltier element for absorbing or generating heat to the light emitting element. A physical quantity detection sensor having a light emitting element module for maintaining a temperature, a signal light section displaced according to a physical quantity, and a reference light section not displaced with respect to the physical quantity, and a gap facing the signal light section of the physical quantity detection sensor An emission end is arranged with a distance therebetween, and a signal light optical fiber that guides emitted light of the light emitting element to irradiate the signal light portion, and receives and guides reflected light from the signal light portion. An emission end is arranged at a predetermined distance from the reference light unit of the physical quantity detection sensor, guides light emitted from the light emitting element to irradiate the reference light unit, and reflects the light from the reference light unit. Light incident The reference light optical fiber to be waved, and the light emitted from the light emitting element is branched into the signal light optical fiber and the reference light optical fiber, and from the signal light portion guided by the signal light optical fiber. A first optical fiber coupler that guides the reflected light of the first optical fiber coupler, and guides the light emitted from the light emitting element branched by the first optical fiber coupler to the reference light optical fiber, and is used as a driver for the light emitting element. A second optical fiber coupler that branches and guides the reflected light from the reference light portion guided by the reference light optical fiber, and the signal light portion guided by the first optical fiber coupler. And a signal detection photodetector for receiving the reflected light of the reference light and converting it into a measurement signal corresponding to the physical quantity, and a thermal expansion of the reference light portion due to a temperature change amount applied to the physical quantity detection sensor and the reference light optical fiber. A reference signal photodetector that receives reflected light corresponding to the displacement due to the displacement via the reference light optical fiber and the second optical fiber coupler and converts the reflected light into a reference signal; and the second optical fiber coupler emits light. A driver signal light detector for receiving the light emitted from the light emitting element branched for a driver of the element and converting the light into a driver signal for the light emitting element; the light emitting element module; the first optical fiber coupler; Fiber coupler,
An optical component for holding a predetermined second temperature by a second Peltier element by attaching optical components such as the signal detection photodetector, the reference signal photodetector, and the driver signal photodetector. The measurement data V _ref (T) (T is the temperature of the physical quantity detection sensor) of the reference signal converted by the attachment member and the reference signal photodetector is converted to initial data of the reference signal at a predetermined constant temperature T _0. A calibration coefficient F _{ref <T 0>} (T) corresponding to a value normalized by dividing by V _ref (T ₀ ) is stored, and the measurement data V of the measurement signal converted by the signal detection photodetector is stored. A value obtained by dividing _sig (P, T) (P is a physical quantity) by initial data V _sig (P ₀ , T ₀ ) of the measurement signal at a predetermined constant physical quantity P ₀ and a predetermined constant temperature T _0. The function F _{sig <P0, T0>} (P, T) corresponding to
_{ref <T0>} Function F corresponding to the value obtained by dividing by (T)
storage means for storing _{norm <P0, T0>} (P, T); the reference signal photodetector; and the initial value data V _ref (T ₀ ) and V _sig ( P ₀ ,
T ₀ ) and the measured value data V _ref (T) and V _sig (P, T) are read and normalized, respectively, and the normalized values and the function F _{ref <T 0>} (T) stored in the storage means are read. And the ratio of the standardized measurement signal to the standardized reference signal, and the calibration coefficient F _{norm <P0, T0>} (P, T) stored in the storage means. And a calculating means for calculating a temperature-compensated physical quantity P from the equation (1).

According to an eighth aspect of the present invention, there is provided a physical quantity detecting apparatus using an optical fiber according to the present invention, wherein a light emitting element and a first Peltier element for absorbing or generating heat to the light emitting element are built-in. A physical quantity detection sensor having a light emitting element module for maintaining a temperature, a signal light section displaced according to a physical quantity, and a reference light section not displaced with respect to the physical quantity, and a gap opposed to the signal light section of the physical quantity detection sensor An emission end is disposed at a distance, and the signal light optical fiber guides the emitted light of the light emitting element to irradiate the signal light portion, and receives and guides the reflected light from the signal light portion. An emission end is arranged at a predetermined distance from the reference light unit of the physical quantity detection sensor, guides light emitted from the light emitting element to irradiate the reference light unit, and reflects the light from the reference light unit. Light incident The reference light optical fiber to be waved, and the light emitted from the light emitting element is branched into the signal light optical fiber and the reference light optical fiber, and from the signal light portion guided by the signal light optical fiber. A first optical fiber coupler that guides the reflected light of the first optical fiber, and guides the light emitted from the light emitting element branched by the first optical fiber coupler to the optical fiber for reference light, and is used as a driver for the light emitting element. A second optical fiber coupler that branches and guides reflected light from the reference light section guided by the reference light optical fiber; and a signal light section guided by the first optical fiber coupler. And a signal detection photodetector for receiving the reflected light of the reference light and converting it into a measurement signal corresponding to the physical quantity, and thermal expansion of the reference light portion due to a temperature change amount of the physical quantity detection sensor and the reference light optical fiber. To A reference signal photodetector that receives reflected light corresponding to the displacement that passes through the reference optical fiber and the second optical fiber coupler and converts the reflected light into a reference signal, and the second optical fiber coupler emits the light. A driver signal photodetector for receiving the light emitted from the light emitting element branched for a driver of the element and converting the light into a driver signal for the light emitting element; the light emitting element module; the first optical fiber coupler; Optical component temperature for mounting optical components such as a fiber coupler, the signal detection photodetector, the reference signal photodetector, and the driver signal photodetector and maintaining a predetermined second temperature by a second Peltier element. Measurement data V _ref (T) (T is the temperature of the physical quantity detection sensor) of the holding signal and the reference signal converted by the reference signal photodetector are converted to initial data at a predetermined constant temperature T _0. A calibration value F _{ref <T 0>} (T) calculated from a value normalized by dividing by V _ref (T ₀ ) is made to correspond to a memory address of a temperature conversion area, and physical quantity data at that temperature is recorded. In addition, the measurement data V _sig (P, T) of the measurement signal converted by the signal detection photodetector is converted to initial data V _sig (P at a predetermined constant physical quantity P ₀ and a predetermined constant temperature T _{0. 0} ,
The calibration coefficient calculated from the standardized value of the measurement signal obtained by dividing by T ₀ ) and the value obtained by dividing by the standardized value of the reference signal is F _{norm <P0, T0>} (P, T) is allocated to a memory address of an area to be converted into a physical quantity, storage means for storing a converted value of a physical quantity corresponding to the memory address in a physical quantity conversion table, and measurement data V _ref (T ) By the initial data V _ref (T ₀ ), and F _{ref <T 0>} (T) corresponding to the standard value obtained by dividing the initial data V _ref (T ₀ ) and the measured data V _sig (T) of the actually measured measurement signal. F _{norm <P0, T0>} (P, T) corresponding to a value obtained by dividing the standard value obtained by dividing V _sig (P ₀ , T ₀ ) by the standard value of the reference signal. And a control circuit for reading a physical quantity from the physical quantity conversion table based on And

According to a ninth aspect of the present invention, in the physical quantity detecting method using an optical fiber according to the present invention, the light emitting device is controlled by the first Peltier device built in the light emitting device module.
A first step of emitting light while maintaining the temperature, and a first optical fiber coupler mounted on the optical component temperature retaining attachment member incorporating the light emitting element module and retaining the second temperature by a second Peltier element The signal light portion of the physical quantity detection sensor that splits the light emitted from the light emitting element into a signal light optical fiber and a reference light optical fiber, and displaces the light emitted from the light emitting element according to the physical quantity by the signal light optical fiber. A second step in which reflected light from the signal light section is incident and passes through the first optical fiber coupler, and the first light is transmitted through the signal light optical fiber.
A reflected light from the signal light portion passing through the optical fiber coupler is received by a signal detection photodetector attached to the optical component temperature holding attachment member, and is converted into a measurement signal according to the physical quantity. 3 steps, the first optical fiber coupler, the light emitted from the light emitting element branched from the signal light optical fiber to the reference light optical fiber by the first optical fiber coupler is attached to the optical component temperature holding attachment member. The two optical fiber couplers split the light for reference light and the light for driver so that the emission light for reference light is not displaced from the optical fiber for reference light with respect to the physical quantity. A fourth step of irradiating at a distance, and causing reflected light from the reference light section to enter and pass through the second optical fiber coupler; and passing through the second optical fiber coupler via the reference light optical fiber. A fifth step of receiving the reflected light from the reference light section with a reference signal photodetector attached to the optical component temperature holding attachment member and converting the reflected light into a reference signal; And a sixth step of receiving light emitted from the light emitting element branched for a driver by a photodetector for a driver signal and converting the light into a signal for driver of the light emitting element.

According to a tenth aspect of the present invention, the signal optical fiber and the reference light optical fiber of the physical quantity detecting device using the optical fiber according to the present invention have a numerical aperture N.P. A having a large A. It is characterized in that A ≧ 0.25. The signal optical fiber and the reference light optical fiber of the physical quantity detection device using the optical fiber according to the present invention described in claim 11 are characterized in that they are hardly bent.

[0016]

The physical quantity detecting device using an optical fiber according to the first aspect of the present invention has a built-in light emitting element and a first Peltier element for absorbing or generating heat to the light emitting element. And a physical quantity detection sensor having a signal light section displaced in accordance with the physical quantity and a reference light section not displaced with respect to the physical quantity, and a gap facing the signal light section of the physical quantity detection sensor. An emission end is arranged at a distance, a signal light optical fiber that guides the emitted light of the light emitting element to irradiate the signal light portion, and receives and guides the reflected light from the signal light portion, An emission end is arranged at a predetermined gap from the reference light unit of the physical quantity detection sensor, guides emitted light of the light emitting element to irradiate the reference light unit, and reflected light from the reference light unit Incident and guided The reference light optical fiber, and the light emitted from the light emitting element is branched into the signal light optical fiber and the reference light optical fiber, and the signal light from the signal light portion guided by the signal light optical fiber. A first optical fiber coupler that guides the reflected light; and a waveguide that guides the light emitted from the light emitting element branched by the first optical fiber coupler to the reference light optical fiber and branches the light emitted from the light emitting element into a driver for the light emitting element. A second optical fiber coupler that guides reflected light from the reference light portion guided by the reference light optical fiber, and a signal light portion guided by the first optical fiber coupler. A signal detection photodetector that receives the reflected light and converts it into a measurement signal corresponding to the physical quantity; and a displacement due to thermal expansion of the reference light section due to a temperature change of the physical quantity detection sensor and the reference light optical fiber. A reference signal photodetector for receiving corresponding reflected light via the reference light optical fiber and the second optical fiber coupler and converting the reflected light into a reference signal; and a driver for the light emitting element using the second optical fiber coupler. A driver signal light detector for receiving light emitted from the light emitting element branched for use and converting the light into a light emitting element driver signal, the light emitting element module, the first optical fiber coupler, the second optical fiber coupler, An optical component temperature holding attachment member for attaching the signal detection photodetector, the reference signal photodetector, and the driver signal photodetector and holding a predetermined second temperature by a second Peltier element; It is characterized by having.

With this configuration, the light emitting element in the light emitting element module is held at the first temperature by the first Peltier element, and the second Peltier is attached together with the optical component attached to the optical component temperature holding attachment member. The element is maintained at the second temperature and is doubly temperature-controlled, constantly emitting light, and the emitted light is split by the first optical fiber coupler into an optical fiber for signal light and an optical fiber for reference light, and The emitted light branched into the optical fiber for light is applied to the signal light portion of the physical quantity detection sensor which is displaced according to the physical quantity, and is reflected from the signal light portion. The reflected light becomes a light amount corresponding to a displacement corresponding to a physical amount applied to the signal light portion, is detected from the signal light optical fiber via the first optical fiber coupler by the signal detection photodetector, and becomes a measurement signal. Is converted. The light emitted from the light emitting element branched into the reference light optical fiber by the first optical fiber coupler is split into light for the driver of the light emitting element and reference light by the second optical fiber coupler, and the reference light passes through the reference light optical fiber. The reference light part of the physical quantity detection sensor is irradiated.

The reference light portion is not displaced with respect to the physical quantity, but is displaced depending on thermal expansion due to temperature change and temperature change of Young's modulus, and is reflected from the reference light portion in accordance with the amount of displacement. The amount of light changes and enters the reference light optical fiber, and the reflected light is received by the reference signal light detector from the reference light optical fiber via the second optical fiber coupler,
It is converted to a reference signal. This reference signal is used for detecting the temperature applied to the physical quantity detection sensor. The driver signal photodetector receives the light emitted from the light emitting element branched by the second optical fiber coupler and converts the light into a driver signal for the light emitting element. It is possible to stabilize the quantity of incident light of the physical quantity detection sensor, and to detect by removing the temperature influence of optical component units such as the signal detection photodetector, reference signal photodetector, and driver signal photodetector. The present invention can be applied to a physical quantity measurement system capable of making the sensitivity constant and compensating for both the zero point and the temperature sensitivity of the physical quantity detection sensor.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A physical quantity detecting device and a physical quantity detecting method using an optical fiber according to the present invention will be described below in detail with reference to the drawings based on an embodiment of the present invention.
FIG. 1 is a block diagram showing a configuration of a physical quantity detection device using an optical fiber according to the first embodiment of the present invention.
In FIG. 1, a light emitting element module 1 incorporates a light emitting element 2 such as an LED (light emitting diode) as a light source, and the first Peltier element 3 keeps the temperature of the light emitting element 2 at a predetermined first temperature T1. It is supposed to. The first Peltier element 3 absorbs heat and generates heat to the light emitting element 2 to make the temperature of the light emitting element 2 constant. A Peltier element is generally called a thermo module, and is assembled by a pair of N-type and P-type semiconductor elements, and heat flows from one side to the other side by passing a direct current, so that the module One side is cooled and the other side is heated. Further, by reversing the polarity of the power supply, the direction of heat transfer is also reversed, so that it can be used for both heating and cooling.

A thermal resistor 4 is interposed between the light emitting element module 1 and the first Peltier element 3. In addition, a first temperature sensor 5 is mounted at a predetermined position in the light emitting element module 1, for example, near the first Peltier element 3. The detection output of the first temperature sensor 5 is input to a first temperature controller 6, and the first temperature controller 6
The first Peltier element 3 is controlled in accordance with the detection output of the first temperature sensor 5, thereby keeping the temperature of the light emitting element 2 constant, so that the light emission amount of the light emitting element 2 becomes constant. I have. Further, the light emitting element 2 is supplied with power from a light emitting element driver 7 having an automatic power control function, whereby the light emitting element 2 is driven at a constant rate,
From this point, light is emitted with a constant light emission amount. The light emitting element module 1 configured as described above is attached together with other optical components attached to (that is, attached to) the optical component temperature holding attachment member 8. The optical component temperature holding attachment member 8 sets the temperature of various optical components attached to the optical component temperature holding attachment member 8 to a second temperature T.
2 is kept constant.

Therefore, the light emitting element module 1
Is maintained at a constant second temperature T2 also by the optical component temperature holding attachment member 8, and as a result, the light emitting element 2 is moved by the light emitting element module 1 and the optical component temperature holding attachment member 8. The temperature is doubly controlled so that the temperature becomes constant. A second Peltier element 9 is attached to a predetermined position, for example, the upper surface of the optical component temperature holding attachment member 8, and a second temperature sensor 10 is also attached in the vicinity thereof. The temperature detection output of the second temperature sensor 10 is
Input to the second temperature controller 11, the second temperature controller 11 controls the second Peltier element 9 in accordance with the temperature detection output of the second temperature sensor 10, and thereby, the optical component temperature holding attachment member 8 Temperature of the second as described above
The temperature is kept constant at T2. Light emitting element 2
Is incident on the incident end of the optical fiber 12 for signal light. The optical fiber for signal light 12 passes through the first optical fiber coupler 13 ([2 × 2 coupler]) and the optical connector 14, and the emission end side thereof is, for example, a pressure converter, a load converter, or the like.
Signal light section 15 of physical quantity detection sensor 15 such as an acceleration converter
a with a predetermined gap therebetween.

As the physical quantity detection sensor 15, for example, a pressure sensor having a diaphragm for detecting the pressure of a fluid, a load transducer, an acceleration transducer, a displacement transducer, and the like are applied. The physical quantity detection sensor 15 includes the signal light section 15a and the reference light section 15b both of which are mirror-finished and can reflect incident light. Are arranged in parallel.
The signal light unit 15a is displaced in accordance with the physical quantity of the measured object (for example, the pressure of the fluid), and the gap between the output end of the signal light optical fiber 12 and the signal light unit 15a changes. ing. Further, the reference light portion 15b does not displace with respect to a physical quantity (for example, the pressure of a liquid). However, thermal expansion by the physical quantity detection sensor 15 itself, displacement due to a change in Young's modulus, and heat It is displaced under the influence of.

Here, the behavior of the physical quantity detection device will be described based on various calculation formulas and characteristic diagrams. First, as the material of the optical fiber, for example, zirconia _(Z r _{O 2)} linear expansion coefficient in the case of using α (RT~800 ℃ ^{average), α1 = 11.0 × 10 -6 (} 1 / ℃) is there. The material of the physical quantity detection sensor 15 is IN
When CONEL718 is used, the temperature change of its linear expansion coefficient (0 to 1000 ° C.) α (T) is α (T) = (1.05934 × 10 ¹ + 2.36140 × 10 ⁻² · T−4.227157) × 10 ⁻⁵ .T ² + 2.70483 × 10 ⁻⁸ .T ³ ) × 10 ⁻⁶ (1 / ° C.) (1). FIG. 8 shows a temperature dependence characteristic diagram of the linear expansion coefficient expressed based on the equation (1).

The temperature change (0 to 10) of the Young's modulus of INCONEL 718 which is the material of the physical quantity detection sensor 15
(00 ° C.) E is: E = 2.07722 × 10 ⁴ −1.15685 × 10 ¹ · T + 5.17163 × 10 ⁻² · T ² −1.91127 × 10 ⁻⁴ · T ³ + 3.47482 × 10 ⁻⁷ T ⁴ -3.0327 × 10 ⁻¹⁰ T ⁵ + 1.02101 × 10 ⁻¹³ T ⁶ [kgf / mm ² ] (2) FIG. 9 shows a characteristic diagram of the temperature change of the Young's modulus expressed based on the equation (2). The thermal expansion α (T) of a material such as INCONEL 718 with a temperature change is expressed by the following equation.

[0025]

(Equation 1)

Here, α (T) is a linear expansion coefficient at a temperature T.
Number (1 / ° C.), L (T) is length (μm) at temperature T,
T is temperature (° C), L₀Is the temperature T₀Length in μm,
It is. Next, the signal light section 15a of the physical quantity detection sensor 15
And the reflecting member of the reference light section 15b is changed to INCONEL71.
8 for signal light at room temperature (25 ° C.).
Gap G between fiber 12 and reference light optical fiber 16
(Μm) reflected light intensity power (G) [μW]
Is power (G) = 9.992733 × 10^-1 + [5.14479 / (1 + 4.52879 × 10^-4・ G²)] ………………… (3) At room temperature, expressed based on this equation (3)
FIG. 10 shows a reflected light intensity characteristic diagram with respect to the gap G. Physics
When the quantity detection sensor 15 is configured by INCONEL718
Physical quantity (eg, fluid pressure) at room temperature (25 ° C.)
Power (P, T) ₀) [Μ
W] is expressed by the following equation (4).

Power (P, T ₀ ) = 1.02693 + {5.0997 / [1 + 2.15243 × 10 ⁻² (8.336137-P) ² ]} (4) FIG. 11 shows a pressure-reflected light intensity characteristic diagram at room temperature of the physical quantity detection sensor 15 expressed based on the equation (4). By the way, the first optical fiber coupler 13 optically couples the light emitted from the light emitting element 2 guided by the signal light optical fiber 12 to the reference light optical fiber 16 and splits the light into the signal light and the reference light. The signal light is guided to the signal light optical fiber 12, and the reference light is guided to the reference light optical fiber 16. The first optical fiber coupler 13 is reflected from the signal light section 15a of the physical quantity detection sensor 15 and
Is guided to the signal detecting photodetector 17 through the optical fiber 12a. The signal detection photodetector 17 includes the signal light optical fiber 1.
2 receives the signal light reflected from the signal light section 15a of the physical quantity detection sensor 15 via the first optical fiber coupler 13 through the first optical fiber coupler 13 and converts the signal light into a measurement signal corresponding to the physical quantity.

This measurement signal is input to the first amplifier 18. The signal processing system after the first amplifying unit 18 will be described later. The light emitted from the light emitting element 2 branched from the optical fiber for signal light 12 to the optical fiber for reference light 16 by the first optical fiber coupler 13 passes through the optical fiber for reference light 16 and the second optical fiber coupler 19 ([2 × 2 coupler]). In the second optical fiber coupler 19, the reference light optical fiber 16 is further divided into two optical fibers 16a and 16b, and the reference light guided by the reference light optical fiber 16 is referred to by the physical quantity detection sensor 15. Reference light for irradiating the light part 15b and driver light for driving the light emitting element 2 are branched, and the branched driver light is transmitted through the optical fiber 16b to the driver signal photodetector 2.
It is guided to zero. The driver signal photodetector 20 receives the driver light and converts it into a driver signal for the light emitting element 2.

The driver signal is input to the input terminal of the light emitting element driver 7. The light emitting element driver 7 drives the light emitting element 2 with constant power by automatic power control by inputting the driver signal. An optical connector 21 is interposed in the vicinity of the emission end side of the reference light optical fiber 16. The reference light branched by the second optical fiber coupler 19 passes through the reference light optical fiber 16a and further passes through the optical connector 21 from the emission end of the reference light optical fiber 16 to the reference light portion 15b of the physical quantity detection sensor 15 Is irradiated. The reference light reflected from the reference light part 15a is incident on the emission end of the reference light optical fiber 16, and
1. The light is guided to the second optical fiber coupler 19 through the reference light optical fiber 16a, and further received by the reference signal light detector 22 from the second optical fiber coupler 19 through the optical fiber 16c. The reference signal photodetector 22 converts the received reference light into a reference signal. This reference signal is
The signal is input to the second amplifier 23. In addition,
As the signal detection photodetector 17, the driver signal photodetector 20, and the reference signal photodetector 22, for example, a photodiode is used.

Thus, the optical component temperature holding attachment member 8
Are optical components for detecting the signal, the photodetector 20 for the driver signal, the photodetector 22 for the reference signal,
1st optical fiber coupler 13, 2nd optical fiber coupler 1
An optical component temperature holding unit for holding the second temperature T2 by mounting the optical connectors 14, 21, the light emitting element module 1, and the like. Further, these constituent members and the physical quantity detection sensor 15 constitute a physical quantity detection device using an optical fiber. Next, the configuration of the signal processing system will be described. First, the output system of the reference signal photodetector 22 will be described. This reference signal photodetector 22
Is input to the second amplifier 23, amplified there, input to an analog / digital converter (hereinafter, referred to as an A / D converter) 24, and converted into a digital signal there. The signal obtained by digitally converting the reference signal is defined as V _ref (T). Here, T represents the temperature of the physical quantity detection sensor 15.

The predetermined constant temperature (usually room temperature 25 ° C.) T _0
Is the output of the A / D converter 24 at V _ref (T ₀ ), and this value is divided by the reference signal output V _ref (T) for normalization. That is, V _ref (T) / V _ref (T ₀ ) (5). The division represented by the equation (5) is performed by the calculation means of the CPU 26, but may be performed by a calculation means such as an analog divider (not shown). The calibration function F obtained by previously calibrating the standardized reference signal (that is, the measured value of the reference light unit 15a) by the least squares fitting method or the like.
_{ref <T0>} equals (T), i.e., the _{V ref (T) / V ref} (T 0) = F ref <T0> (T) the temperature T according to the amount detecting sensor 15 as ............ (6) Ask. This function F _{ref <T0>} (T) is stored in advance in a ROM 25 (read-only memory) as storage means.

FIG. 1 shows an example of the calibration function F _{ref <T0>} (T).
It is shown in FIG. FIG. 12 shows the temperature [deg] on the horizontal axis,
The vertical axis indicates the calibration function F _{ref <T0>} (T).
Here, the reason for normalization with the output of the temperature T ₀ is that the physical quantity detection sensor 15 is attached to the optical component temperature holding attachment member 8 via the reference light optical fiber 16 and the reference light optical fiber 16 a This is for correcting the connection loss with the optical connector 21 at the time of connection to the optical connector 21 by taking a ratio. Note that a specific method of converting to the temperature T will be described later. Next, a method of detecting a physical quantity applied to the signal light unit 15a of the physical quantity detection sensor 15 will be described. in this case,
The signal light portion 15a is displaced in accordance with a physical quantity, for example, pressure applied to the signal light portion 15a, and a gap between the signal light portion 15a and the emission end of the signal light optical fiber 12 is formed in accordance with the displacement. The amount of the reflected light received from the signal light portion 15a incident on the emission end of the signal light optical fiber 12 fluctuates according to the amount of the change.

As described above, the signal light section 15 in which the light amount fluctuates.
The reflected light from a is guided to the signal light optical fiber 12 in the opposite direction, is received by the signal detection light detector 17 via the optical connector 14 and the first optical fiber coupler 13, and is converted as a measurement signal. After that, the signal is input to the first amplifier 18. This measurement signal is amplified by the first amplifier 18 and A
The signal is input to the / D converter 24 and is converted into a digital signal to be V _sig (P, T). This measurement signal,
Similarly to the case of the reference signal, V _sig (P, T) is a signal detection light at a predetermined constant physical quantity (for example, fluid pressure) P _{0 and a} constant temperature (normally, room temperature 25 ° C.) T _0. Detector 1
7, the output V of the A / D converter 24
_The signal light output, that is, the measurement signal is divided by the value of _sig (P ₀ , T ₀ ) for normalization. That is, V _sig (P, T) / V _sig (P ₀ , T ₀ ) (7) Note that the division in the equation (7) may be performed by the calculating means of the CPU 26 or may be performed by a calculating means using an analog divider (not shown).

Here, a predetermined constant physical quantity P ₀ (normally, no load) _{and a} constant temperature T ₀ (normally, room temperature 25 ° C.) A
In / D converter 24 output V _sig of (P _0, T _0), any pressure P (load pressure), reason for normalizing by dividing the output V _sig (P, T) at temperature T, the ( As in the case of the expression 6), the light for signal light which constitutes the optical component temperature holding unit in which the physical quantity detection sensor 15 is attached to the optical component temperature holding attaching member 8 via the optical fiber 12 for signal light. This is for correcting the connection loss with the optical connector 14 when connecting to the fiber 12 by taking a ratio. Also, the corresponding function F _{sig <P0, T0>} (P, T) is
_{ref <T0>} (T) and to previously obtain the calibration of such pre-least-squares fitting method _{similarly, V sig (P, T)} / V sig (P 0, T 0) = F sig <P0, T0> ( P, T)... (8)

The function F _{sig <P0, T0>} (P, T) is also R
It is stored in the OM 25 in advance. FIG. 13 shows the function F _{sig <P0, T0>} (P,
FIG. 4 is a characteristic diagram showing a relationship between T) and a physical quantity (pressure), wherein the horizontal axis represents the physical quantity {pressure (MPa)}, and the vertical axis represents F.
_{sig <P0, T0>} (P, T). As is clear from FIG. 13, not only does the zero point of the physical quantity detection sensor 15 change with a change in temperature, but also the output sensitivity to the physical quantity (pressure) varies with the temperature change of the Young's modulus of the material constituting the physical quantity detection sensor 15. It can be seen that correction of the temperature effect of the zero point alone is not sufficient.
Here, the reason for normalizing with the output of the constant physical quantity P _{0 and the} constant temperature T ₀ is that the physical quantity detection sensor 15 is connected to the optical fiber 12 for the signal light of the attaching member for holding the optical component temperature, as before.
Optical connector 1 for connection to reference call optical fiber 16
This is for correcting by taking the connection loss ratio of the connection portions 4 and 21.

Further, the ratio between the reference signal ratio and the measurement signal ratio is calculated. That is, the calculation is performed according to [V _sig (P, T) / V _sig (P ₀ , T ₀ )] / [V _ref (T) / V _ref (T ₀ )] (9). The division shown in this equation (9) is also performed by the CPU
26, or may be performed by an analog divider (not shown). FIG. 14 shows F _{sig <P0, T0>} (P, T) / _{Fref <T0>} (T) = F _{norm <P0, T0>} (P, T) using temperature as a parameter. An example of a characteristic diagram is shown.

The function F shown in the equation (10)
_{norm <P0, T0>} (P, T) is also stored in the ROM 25. In FIG. 14, the horizontal axis represents the physical quantity {pressure (MPa)}, and the vertical axis represents F _{norm <P0 , T0>} (P, T). In the CPU 26, V _ref (T) / V _ref (T ₀ ) and RO
The function _{Fr ef <T0>} (T) stored in M25 is stored in ROM
Is read from the 25, and _{V ref (T) / V ref} (T 0) and the calibration function F _{ref <T0>} (T) are _{equal, V ref (T) / V} ref (T 0) = F ref <T0 _> (T) Solve by numerical calculation (software, for example, Newton-Raphson method) to find the temperature T. The obtained temperature T is substituted for the right side of the above equation (10), and the left side is similarly subjected to a numerical calculation as a measured value to finally calculate a temperature-compensated physical quantity P (for example, fluid pressure). ing. As described above, in the CPU 26, only the coefficients of the calibrated function formula are written in the ROM 25 as calibration coefficients, and the program for obtaining the solution of the formula (10) can be executed to calculate the physical quantity P with the required calculation accuracy. it can.

The physical quantity P calculated by the CPU 26 is converted into an analog signal by a digital / analog converter 27 (hereinafter referred to as a D / A converter) and then displayed on a display 28 or an analog output 29. ing. next,
The operation of the first embodiment of the present invention configured as described above will be described. First, the operation of the optical component temperature holding unit will be described. The temperature in the light emitting element module 1 is detected by the first temperature sensor 5 in the light emitting element module 1, and the first temperature controller 6 controls the driving of the first Peltier element 3 based on the detected output, and the first temperature T1 And the driving power of the light emitting element 2 is automatically controlled by the light emitting element driver 7 so that the light emitting element 2 always emits light with a constant light emission amount. The emitted light is transmitted through a first optical fiber coupler 13 through an optical fiber 12 for signal light.
Is guided to. Further, the temperature of the optical component temperature holding attachment member 8 is constantly detected by the second temperature sensor 10 attached to the optical component temperature holding attachment member 8, and the detection output is sent to the second temperature controller 11. By outputting the output, the second Peltier element 9 is controlled by the second temperature controller 11 and the temperature of the optical component temperature holding attachment member 8 is constantly maintained at the second temperature.
The temperature is maintained at T2.

Thus, each optical component of the optical component temperature holding unit attached to the optical component temperature holding attachment member 8 is always maintained at the second temperature T2. This second
The emitted light from the light emitting element 2 is optically coupled between the signal light optical fiber 12 and the reference light optical fiber 16 by the first optical fiber coupler 13 held at the temperature T2, and the emitted light is split into two. . One of the two branched light beams is guided from the first optical fiber coupler 13 to the signal light optical fiber 12 and passes through the first optical connector 14 to the physical quantity detection sensor 1.
No. 5 through the gap between the signal light portion 15a and the output end of the signal light optical fiber 12, the signal light portion 15a is irradiated.
The signal light section 15a is displaced in accordance with the applied physical quantity, and is also displaced in accordance with the thermal expansion and the Young's modulus temperature change due to the temperature change applied to the physical quantity detection sensor 15. The signal light section 15a and the signal light are displaced by these displacements. The gap between the optical fiber 12 and the emission end also varies.

When the gap between the reflection surface of the signal light section 15a and the output end of the signal light optical fiber 12 fluctuates, the reflection surface of the signal light section 15a moves from the reflection surface of the signal light section 15a in accordance with the amount of the fluctuation. The amount of reflected light incident on the emission end changes. When the changed reflected light is again incident on the emission end of the optical fiber for signal light 12 as signal light for measurement, the signal light is transmitted to the first optical connector 14, the optical fiber for signal light 12, and the first optical connector 12.
The light is guided to the signal detection photodetector 17 via the optical fiber coupler 13 and the signal light optical fiber 12a, where it is converted into a measurement signal and input to the first amplifier 18. on the other hand,
The first optical fiber coupler 13 uses the reference light optical fiber 1
The emitted light branched into 6 is guided to the second optical fiber coupler 19. In the second optical fiber coupler 19, the reference light optical fiber 16 is branched into optical fibers 16a and 16b, and the emitted light guided by the reference light optical fiber 16 is divided into the reference light optical fiber 16a and the optical fiber. The optical signal is coupled to the optical fiber 16b, and the optical signal is branched into a reference signal light guided as it is to the optical fiber for reference light 16a and a driver signal light guided to the optical fiber 16b.

The driver signal light guided to the optical fiber 16b is received by the driver signal photodetector 20, and outputs the driver signal light to the light emitting element driver 7. As a result, the light emitting element driver 7 operates the light detector 2 for driver signal.
The light emitting element 2 is driven by automatic power control according to the output of 0, and from this point, the light emitting element 2 emits light with a constant light amount. The reference signal light branched into the reference light optical fiber 16 by the second optical fiber coupler 19 passes through the reference light optical fiber 16a and the optical connector 21 and from the output end of the reference light optical fiber 16 to the physical quantity detection sensor. Irradiate 15 reference light portions 15b. The reference light portion 15b is formed while maintaining rigidity that is not displaced by a physical quantity. It does not change, but changes due to thermal expansion due to a temperature change applied to the physical quantity detection sensor 15 and the reference light optical fiber 16. Due to this change, the reflected light reflected from the reflecting surface of the reference light portion 15b changes, and the light amount of the reference signal light re-entering the emission end of the reference light optical fiber 16 changes.

The reflected light of the reference light portion 15b re-entered into the reference light optical fiber 16 is guided to the second optical fiber coupler 19 through the optical connector 21 and the reference light optical fiber 16a as reference signal light. Where the optical fiber 16c
, And is received by the reference signal photodetector 22 and input to the second amplifier 23 as a reference signal which is an electric signal. Next, the operation of the signal processing system after the first amplifying unit 18 and the second amplifying unit 23 will be described with reference to the flowcharts shown in FIGS. The flowcharts shown in FIGS. 2 and 3 show the processing procedure executed by the CPU 26. FIG. 2 shows the processing procedure of the preceding stage, and FIG. 3 shows the processing procedure of the subsequent stage. First, in step S1 shown in FIG. 2, the calibration function coefficient (hereinafter referred to as “function”) F _{ref <T0>} (T) shown in the above equation (6) is stored in the ROM 25, and The function F _{norm <P0, T0>} (P, T) shown in the equation is stored in the ROM 25.

In this state, the reference signal V _ref (T ₀ ) measured from the reference light portion 15b of the physical quantity detection sensor 15 at the constant temperature T ₀ of the physical quantity detection sensor 15 is detected by the reference signal photodetector 22. The signal is converted into a digital signal by the A / D converter 24 via the second amplifying unit 23 and input to the CPU 26 as initial value data (step S2). Similarly, the measurement signal V _sig (P ₀ , T ₀ ) measured from the signal light portion 15a of the physical quantity detection sensor 15 at the constant temperature T ₀ and the constant physical quantity P ₀ of the physical quantity detection sensor 15 is a signal detection light. Detected by the detector 17 and passed through the first amplification unit 18 to A
The signal is converted into a digital signal by the / D converter 24 and input to the CPU 26 as initial value data (step S2).
Next, the reference signal V _ref (T) measured from the reference light section 15b of the physical quantity detection sensor 15 at an arbitrary actual temperature T of the physical quantity detection sensor 15 is transmitted to the A / A via the second amplification section 23. It is converted into a digital signal by the D
U26 is input as reference light measurement value data (step S3).

Similarly, the measurement signal V _sig (P, T) from the signal light section 15 a of the physical quantity detection sensor 15 at the temperature T of the physical quantity detection sensor 15 is _subjected to A / D conversion via the first amplification section 18. Is converted into a digital signal by the detector 24 and input to the CPU 26 as signal light measurement value data (step S
3). Next, the CPU 26 normalizes the reference signal obtained from the reference light unit 15b of the physical quantity detection sensor 15.
In this case, as shown in the above equation (5), V _ref (T) /
Divide V _ref (T ₀ ) (step S4). Similarly, the measurement signal from the signal light section 15a of the physical quantity detection sensor 15 is normalized. In this case, the division of V _sig (P, T) / V _sig (P ₀ , T ₀ ) is performed as shown in the above equation (7) (step S4). Next, the process proceeds to the processing procedure of the CPU 26 as shown in the flowchart of FIG. Step S5
Then, a temperature conversion process is performed. In this case, the ratio of the reference signal obtained from the reference light section 15b of each physical quantity detection sensor 15 at the temperature T of the physical quantity detection sensor 15 and the constant temperature T ₀ , that is, the normalization expressed by the above equation (5) The obtained signal V _ref (T) / V _ref (T ₀ ) is equal to the calibrated function F _{ref <T 0>} (T), that is, V _ref (T) / V _ref (T ₀ ) = F _{ref <T 0} The temperature T of the physical quantity detection sensor 15 is determined as _> (T) (step S5). FIG. 12 shows this calibrated function F
The relationship between _{ref <T0>} (T) and temperature is shown.

Thus, the physical quantity detection sensor 15
Constant temperature T when converting temperature T ₀Physical quantity detection
The reference signal obtained from the reflected light of the reference light portion 15b of the sensor 15
By standardizing the physical quantity detection sensor 15,
Reference light beam attached to the optical component temperature holding attachment member 8
When connecting to the fiber 16, connect the optical connector 21 or the like.
Can be corrected by taking the ratio
it can. Next, at the temperature T of the physical quantity detection sensor 15,
The measurement of the physical quantity P will be described. Physical quantity detection sensor 1
5 is the measurement signal V detected from the reflected light of the signal light unit 15a.
_sig(P, T) is A / D converted via the first amplifying unit 18.
Is converted into a digital signal by the detector 24 and input to the CPU 26
Is done. Also, the constant temperature T of the physical quantity detection sensor 15₀You
And constant physical quantity P₀Signal light of the physical quantity detection sensor 15 at
Measurement signal V detected from unit 15a_sig(P₀, T₀) Is
1 Digitally converted by the A / D converter 24 via the amplifying unit 18
The signal is converted into a signal and input to the CPU 26. These totals
The ratio of the measured signals, ie, as shown in the above equation (7),
And V_sig(P, T) / V_sig(P₀, T₀) As physical quantity detection
The measurement signal detected from the signal light section 15a of the sensor 15 is
Standardize.

That is, as shown in the above equation (8), V _sig (P, T) / V _sig (P ₀ , T ₀ ) = F
_{Let sig <P0, T0>} (P, T). FIG. 13 shows an example of the relationship between the function F _{sig <P0, T0>} (P, T) using the temperature of the signal light portion of the physical quantity detection sensor 15 as a parameter and the physical quantity (pressure). As described above, according to the temperature of the physical quantity detection sensor 15, the output sensitivity together with the fluctuation of the zero point of the physical quantity detection sensor 15 changes due to the temperature change of the Young's modulus of the physical quantity detection sensor 15 from FIG. It can be seen that correction alone is not sufficient.

FIG. 9 shows the physical quantity detection sensor 15
Temperature change of the Young's modulus (0
C. to 600 C.). Thus, the constant physical quantity P ₀ applied to the physical quantity detection sensor 15 and _the constant temperature T ₀
In the same manner as described above, the loss ratio of the connection light of the connection portion of the optical connector 14 when the physical quantity detection sensor 15 is connected to the optical fiber 12 for signal light can be calculated. Can be corrected. Furthermore, CPU
26 takes the ratio of the measurement signal shown in the above equation (7) and the ratio of the reference signal shown in the above equation (5) as shown in the above equation (9). The denominator [V _ref (T) / V in this equation (9)
_ref (T ₀ )] is F _{ref <T 0>} (T), and (9)
If the calibration function of the numerator [V _sig (P, T) / V _sig (P ₀ , T ₀ )] in the equation is F _{sig <} P ₀ , T _{0 >} (P, T), the above (9)
The left side of the equation is F _{sig <P0, T0>} (P, T) / F
_{ref <T0>} (T), and the calibration function F at this time
_{norm <P0, T0 >} (P, T) is equal, that is, as shown in the above equation (10), _{Fsig <P0, T0>} (P, T) / _{Fref <T0>} (T) = F
_{norm <P0, T0>} (P, T).

FIG. 14 shows the calibration function F of the equation (10) when the temperature of the physical quantity detection sensor 15 is used as a parameter.
_{An example of norm <P0, T0>} (P, T) is shown. As described above, in the first embodiment, as described above, [V _ref (T) / V _ref (T ₀ )] of the denominator of the above equation (9).
And the calibration function _{Fref <T0>} (T) are equal, the temperature T of the physical quantity detection sensor 15 is obtained by numerical calculation (1
0) is substituted into the right side of the equation, and the left side is similarly measured as a measured value, and the same numerical calculation is performed. Finally, the temperature of the physical quantity detection sensor 15 is compensated, so that it is detected from the signal light section 15a of the physical quantity detection sensor 15. The physical quantity P is calculated (for example, pressure conversion) (step S6).

The calculated physical quantity P is converted from a CPU 26 into an analog signal by a D / A converter 27 and sent to a display 28, where it is displayed and also output as an analog output 29. In step S6, the physical quantity P
Is calculated, the CPU 26 sets the physical quantity detection sensor 15
A determination is made in step S7 as to whether or not the next physical quantity is to be measured in step S7. If it is determined that the next physical quantity is not to be measured, the above series of processing is terminated. When the measurement of the next physical quantity is further performed, the process returns to step S3 in FIG. 2 again, and the series of processing steps from step S3 to step S7 is repeated again. In the first embodiment, only the coefficients of the calibrated function are stored in the ROM 25, and a program process for finding a solution is executed. Therefore, the calculation for executing this program takes some time.
This has the advantage that the amount of information stored in M25 is small.

As described above, in the first embodiment of the present invention, the temperature is controlled by the second Peltier element 9 so that the temperature of the optical component temperature holding attachment member 8 is kept constant at the second temperature T2. By keeping the temperature of each optical component constituting the optical component temperature holding unit constant, the temperature effect of each optical component is eliminated and the light emitting element module 1 including the light emitting element 2 as a light source is connected to the first Peltier element. By controlling the first temperature T1 in step 3, the temperature of the light emitting element 2 is doubly controlled, and the amount of emitted light is stabilized. Further, the physical quantity detection sensor 15 is provided with a reference light section 15b which is not displaced by a physical quantity, and furthermore, a reference signal from the reference light section 15b is passed through an optical fiber for reference light, an optical connector 21 or the like which is kept constant at the second temperature T2. And a signal light portion 15a of the physical quantity detection sensor 15 which is displaced by a physical quantity.
The optical fiber 12 for signal light, which is maintained at a constant temperature at the second temperature T2, is also detected via the optical connector 14 and the like,
Since the ratio between the reference signal and the measurement signal is compared with a calibration function stored in the ROM 25, a temperature is obtained, and a physical quantity that compensates for the effects of temperature, thermal expansion, and Young's modulus is calculated. High-accuracy physical quantity measurement that compensates for temperature effects such as a change in zero point and a change in sensitivity as a total of the physical quantity detection sensor 15 can be performed.

Next, a description will be given of a second embodiment of a physical quantity detecting device and a physical quantity detecting method using a fiber according to the present invention. FIG. 4 is a block diagram showing the configuration of the second embodiment. The second embodiment shown in FIG. 4 aims at a higher processing speed than the first embodiment shown in FIG. In FIG. 4, FIG.
The same parts as those in FIG. 1 are denoted by the same reference numerals, and repeated description will be avoided, and parts different from FIG. 1 will be mainly described. This FIG.
As is apparent from comparison with FIG.
A control circuit 30 is provided in place of the PU 26. The control circuit 30 includes an A / D converter 2
4. The ROM 25 and the D / A converter 27 are controlled. Other configurations are the same as those in FIG. This FIG.
In the second embodiment shown in FIG. 7, instead of using software (program) as in the first embodiment, a hardware such as a PLD (programmable logic device, etc.) This is an embodiment in the case where a physical quantity P (for example, pressure of a fluid) which is subjected to a special process and is temperature-compensated is output.

FIGS. 5 and 6 are flowcharts showing the processing procedure of the CPU 26 according to the second embodiment, of which FIG. 5 is a flowchart showing the processing procedure of the preceding stage, and FIG. 6 is a flowchart showing the processing procedure of FIG. First, in the flowchart shown in FIG.
The processing from step S2 to step S4 is exactly the same as step S2 to step S4 in the flowchart shown in FIG. 5 described in the first embodiment. Therefore, the description of that portion is omitted in the second embodiment. In the second embodiment, as in the case of the first embodiment, the physical quantity detection sensor 15 performs processing in hardware without using software (program).
Temperature-compensated physical quantity P (eg, fluid pressure, etc.)
Is what you get.

That is, as obtained in step S4 of the flowchart of FIG. 2 in the first embodiment, the temperature T of the physical quantity detection sensor 15 corresponding to the finally required physical quantity resolution (accuracy) is constant. The ratio between the reference signals V _ref (T) and V _ref (T ₀ ) from the reference light unit 15b of each physical quantity detection sensor 15 at the temperature T ₀ , that is, V
_ref (T) / V _ref (T ₀ ) calibration function F _{ref <T 0>} (T);
The ratio of the measurement signal at each of the temperature T of each of the physical quantity detection sensors 15 and the constant temperature T ₀ detected from the signal light portion 15a of each of the physical quantity detection sensors 15 shown in the above equation (9), that is, V _sig ( P, T) / V _sig (P ₀ , T ₀ ) calibration function F
_The calibration data table calculated from _{sig <P0, T0>} (P, T) is written in the ROM 25 as numerical data (FIG. 6).
Step S8). That is, the area of the ROM 25 is converted into a temperature conversion data area for converting the temperature of the physical quantity detection sensor 15 and a physical quantity (for example, fluid pressure) detected by the signal light unit 15a of the physical quantity detection sensor 15 at the converted temperature. Divide into two data areas.

The area of the ROM 25 divided into these two
In the temperature conversion data area, the above equation (10) is used.
Calibration function F_{ref <T0>}(T) value to memory address
Respond. This memory address contains a physical quantity detection sensor
15 physical quantity data (for example, fluid pressure
Start address (for example, no load)
Time data address). Also, in terms of physical quantities,
In the data area to be calculated, the calibration function shown in the above equation (10) is used.
Number F _{norm <P0, T0>}Address corresponding to the value of (P, T)
Is distributed starting from the above start address,
Store the physical quantity corresponding to this address, and
By reading the physical quantity by the control circuit 30,
Detected by the signal light portion 15a of the physical quantity detection sensor 15.
The measured signal is converted into a physical quantity. This control circuit
The physical quantity converted by the control circuit 30
Is output to the D / A converter 27, where the first actual
Converted to analog signals in the same way as in the embodiment.
After that, while being output to the display 28, the analog output 2
9 is also output.

In the second embodiment, the above equation (6) is used from the ratio V _ref (T) / V _ref (T ₀ ) of the physical quantity measurement signal detected by the signal light section 15a of the physical quantity detection sensor 15. There is no need to store the temperature conversion table in the ROM 25,
The ratio V _ref (T) / V _ref (T ₀ ) of the measured reference signal, [V _sig (P, T) / V _sig (P ₀ , T ₀ )] shown in the above equation (9).
ROM2 corresponding to the value of / [V _ref (T) / V _ref (T ₀ )]
It is only necessary to read the value of the digital physical quantity at the memory address of No. 5, so that higher-speed processing is possible than in the case of the first embodiment. Although the storage capacity of the ROM 25 increases, there is no particular problem in consideration of the current memory capacity and clock speed. In addition, the present invention
The present invention is not limited to the embodiment described above and shown in the drawings, and can be variously modified and implemented without changing the gist thereof. For example, in the third embodiment shown in FIG. 7, an optical fiber coupler is added to the first and second embodiments shown in FIGS. The number of times of passage through the optical fiber coupler in the process up to the detection photodetector and the reference signal photodetector is equalized, and the transmission loss of the signal light is equalized to improve the measurement accuracy. In the third embodiment, the description of the parts common to the first and second embodiments will be omitted, and only different parts will be described.

In FIG. 7, 31 is a common optical fiber,
32 is an optical fiber for signal light, 33 is an optical fiber for reference light, 34 is an optical fiber for driver signal light, 35 is a first optical fiber coupler, 36 is a second optical fiber coupler, 37 is a third optical fiber coupler, 38 Reference numerals 42 are optical connectors. Light emitted from the light emitting element 2 in the light emitting module 1 is transmitted from the common fiber 31 to the first optical fiber coupler 3.
5, the light is branched into an optical fiber 32 for signal light and an optical fiber 33 for reference light. The light emitted from the optical fiber for signal light 32 is transmitted to the second optical fiber coupler 36.
Optical connector 38, signal light optical fiber 32
Then, the light is emitted from the emission end to the reflection surface forming the signal light portion 15a of the physical quantity detection sensor (for example, pressure sensor) 15 separated by a gap. Then, the signal light unit 15a
Is reflected by the optical fiber 32 for signal light, is guided through the optical connector 38, the second optical fiber coupler 36, and the optical connector 39, and is detected by the optical detector 1 for signal detection.
7 converts it into a measurement signal.

On the other hand, the emitted light from the light emitting element 2 branched by the first optical fiber coupler 35 is guided by the reference light optical fiber 33, and the third optical fiber coupler 37, the optical connector 40, the reference light The physical quantity detection sensor 1 is separated from the emission end via the fiber 33 by a predetermined distance.
No. 5 is emitted to the reflection surface forming the reference light portion 15b. Then, the reflected light reflected by the reference light unit 15b enters the reference light optical fiber 33, and passes through the optical connector 40, the third optical fiber coupler 37, the reference light optical fiber 33, the optical connector 41, and the like. Guided photodetector 22 for reference signal
Is converted into a reference signal. Further, the emitted light from the light emitting element 2 branched by the first optical fiber coupler 35 is guided by the reference light optical fiber 33, and the third optical fiber coupler 37, the driver signal light optical fiber 34,
The light enters the driver signal photodetector 20 via the optical connector 42 and is converted into a driver signal. Subsequent processing of the measurement signal, the reference signal, and the driver signal thus converted is substantially the same as that described in the first embodiment, and a description thereof will not be repeated.
As described above, the number of optical fiber couplers and the number of optical connectors interposed in the optical path from the light emitted from the light emitting element 2 to the signal detection photodetector 17 and the reference signal photodetector 22 are the same. Therefore, the luminance levels of the signal light and the reference light are substantially equalized, the measurement signal and the reference signal are obtained with the same accuracy, and further, data corresponding more accurately to the physical quantity is obtained.

[0058]

As is apparent from the above description, according to the first aspect of the present invention, the light emitting device and the first Peltier device which has a heat absorbing or heat generating effect on the light emitting device are incorporated. A light emitting element module that holds a predetermined first temperature, a physical quantity detection sensor having a signal light section that is displaced in accordance with a physical quantity and a reference light section that is not displaced with respect to the physical quantity, and a signal light section of the physical quantity detection sensor. An emission end is disposed opposite to and with a gap therebetween, and the light emitted from the light emitting element is guided to irradiate the signal light, and the reflected light from the signal light is incident and guided. An optical fiber and an emission end are arranged at a predetermined distance from the reference light section of the physical quantity detection sensor, guide the light emitted from the light emitting element to irradiate the reference light section, and irradiate the reference light with the reference light. Reflected light from the part The reference light optical fiber that is incident and guided, and the light emitted from the light emitting element is branched into the signal light optical fiber and the reference light optical fiber, and the light guided by the signal light optical fiber. A first optical fiber coupler that guides reflected light from the signal light unit; and a waveguide that guides light emitted from the light emitting element branched by the first optical fiber coupler to the reference light optical fiber; A second optical fiber coupler that branches off for the driver and guides the reflected light from the reference light portion guided by the reference light optical fiber; and the second optical fiber coupler guided by the first optical fiber coupler. A signal detection photodetector that receives reflected light from the signal light unit and converts it into a measurement signal corresponding to the physical quantity; and the reference light based on a temperature change amount applied to the physical quantity detection sensor and the reference light optical fiber. A reference signal photodetector for receiving reflected light corresponding to a displacement due to thermal expansion of the reference light via the reference light optical fiber and the second optical fiber coupler and converting the reflected light into a reference signal; and the second optical fiber coupler A driver signal light detector for receiving the light emitted from the light emitting element branched for a driver of the light emitting element and converting the light into a driver signal for the light emitting element; the light emitting element module; the first optical fiber coupler; Attach optical components such as a second optical fiber coupler, the signal detection photodetector, the reference signal photodetector, and the driver signal photodetector, and maintain a predetermined second temperature by a second Peltier element. Optical components such as a light emitting element, an optical fiber, an optical fiber coupler, and a photodetector. The light-emitting element module, which is held by the attaching member and has a particularly large temperature influence, is further maintained at a predetermined temperature by the unique first Peltier element and is double-temperature-maintained. It is possible to provide a physical quantity detection device using an optical fiber which can almost certainly eliminate the influence of temperature and can stably measure a physical quantity even at a high temperature utilizing the heat resistance which is an advantage of the optical fiber.

According to the second aspect of the present invention, in addition to the effect of the first aspect, the light emitted from the light emitting element is emitted by the signal detection photodetector and the reference signal light. Since the number of optical fiber couplers and the number of optical connectors interposed in the optical path leading to the detector are the same, the luminance levels of the signal light and the reference light are substantially aligned, and the measurement signal and the reference signal are It is possible to provide a physical quantity detection device using an optical fiber that can be obtained with the same accuracy and, moreover, obtains data that accurately corresponds to physical quantities. According to the third aspect of the present invention, the light emitting element module controls the first Peltier element by the first temperature controller based on the temperature detected by the first temperature sensor provided therein. Since the light emitting element module is configured to be maintained at the first temperature, the light emitting element module is always kept at the first temperature.
Therefore, it is possible to provide a physical quantity detection device using an optical fiber, which is capable of emitting light with stable luminance.

According to the fourth aspect of the present invention, the optical component temperature holding attachment member is controlled by the second temperature controller based on the temperature detected by the second temperature sensor provided at a predetermined position. Since the second temperature is maintained by controlling the two Peltier elements, a physical quantity detection device using an optical fiber that can stably operate the optical component unit and realize highly accurate physical quantity measurement can be provided. Can be provided. According to the invention described in claim 5, the light emitting element emits light by being automatically controlled by a light emitting element driver based on a driver signal of the light emitting element converted by the driver signal light detector. Provided is a physical quantity detection device using an optical fiber that can stabilize the emission luminance to a physical quantity detection sensor in addition to stably emitting light from a light emitting element and thus can detect a physical quantity with high luminance. be able to. According to the invention described in claim 6, the physical quantity detection sensor is a pressure sensor, and the diaphragm portion facing the emission end of the optical fiber for signal light, and the rigid body portion facing the optical fiber for reference light. Therefore, the physical quantity is exclusively obtained by receiving the displacement of the diaphragm part by the optical fiber for signal light, receiving the displacement due to the temperature of the diaphragm part by the optical fiber for reference light facing the rigid body part, and from these two optical fibers. It is possible to provide a physical quantity detection device using an optical fiber that can accurately measure the pressure of various fluids by removing an error due to the influence of temperature based on the measurement signal and the reference signal.

According to the seventh aspect of the present invention, in addition to the configuration of the first aspect, the first light-emitting element for reference signal and the first light-emitting element having an endothermic or exothermic effect on the light-emitting element are provided. A light emitting element module having a built-in Peltier element for maintaining a predetermined first temperature, a physical quantity detection sensor having a signal light section displaced according to a physical quantity and a reference light section not displaced with respect to the physical quantity, and the physical quantity detection sensor An emission end is arranged with a gap in opposition to the signal light portion, guides light emitted from the light emitting element to irradiate the signal light portion, and receives reflected light from the signal light portion. An emission end is disposed at a predetermined distance from the signal light optical fiber for guiding the light and the reference light part of the physical quantity detection sensor, and guides the light emitted from the light emitting element to irradiate the reference light part. And the reference beam A reference light optical fiber that receives and reflects the reflected light of the reference light, a light emitted from the light emitting element is branched into the signal light optical fiber and the reference light optical fiber, and is guided by the signal light optical fiber. A first optical fiber coupler that guides the reflected light from the signal light unit, and a light emitting element that is branched by the first optical fiber coupler and emits light emitted from the light emitting element to the reference light optical fiber. A second optical fiber coupler that is branched for a driver of the light emitting element and guides reflected light from the reference light section guided by the reference light optical fiber, and guided by the first optical fiber coupler. A signal detection photodetector that receives the waved reflected light from the signal light unit and converts the reflected light into a measurement signal corresponding to the physical quantity, and a temperature change amount applied to the physical quantity detection sensor and the reference light optical fiber. by A reference signal photodetector that receives reflected light corresponding to a displacement due to thermal expansion of the reference light unit via the reference light optical fiber and the second optical fiber coupler and converts the reflected light into a reference signal; A driver signal photodetector for receiving the light emitted from the light emitting element branched by the two optical fiber coupler for the driver of the light emitting element and converting the light into a driver signal for the light emitting element; the light emitting element module; Optical components such as a fiber coupler, the second optical fiber coupler, the signal detection photodetector, the reference signal photodetector, and the driver signal photodetector are attached, and a predetermined second Peltier device is used. Optical component temperature holding attachment member for holding temperature, and measurement data V of the reference signal converted by the reference signal photodetector
_ref (T) (T is the temperature of the physical quantity detection sensor) divided by the initial data V _ref (T ₀ ) of the reference signal at a predetermined constant temperature T ₀ , and a calibration coefficient F _{ref <} corresponding to a normalized value. _T0> (T)
And the measured data V _sig (P, T) (P is a physical quantity) of the measurement signal converted by the signal detection photodetector at a predetermined constant physical quantity P ₀ and a predetermined constant temperature T ₀ . initial data V _sig of the measurement signal (P _0, T ₀₎ function corresponding to the value normalized by dividing the _{F sig <P0, T0> (} P, T)
And a function F _{norm <P0, T0>} (P, T) corresponding to a value obtained by dividing the above by the calibration coefficient F _{ref <T0>} (T), and the reference signal photodetector And the initial value data V _ref (T ₀ ) and V converted by the signal detection photodetector.
_sig (P ₀ , T ₀ ) and measured value data V _ref (T) and V
_sig (P, T) are read and normalized, respectively, and the normalized value and the function F stored in the storage means are stored.
_{ref <T0>} (T) to determine the temperature T, the ratio between the standardized measurement signal and the standardized reference signal, and the calibration coefficient F stored in the storage means.
and a calculating means for calculating a temperature-compensated physical quantity P from _{norm <P0, T0>} (P, T), so that the physical quantity detection sensor is connected to the optical connector via the signal light optical fiber. The connection loss when connecting to the optical connector can be corrected, and the connection loss when connecting the physical quantity sensor to the optical connector can be further corrected. For example, it is possible to provide a physical quantity detection device using an optical fiber capable of compensating a temporal change of a light intensity output of a light source, that is, a light intensity element when performing dynamic pressure measurement.

According to an eighth aspect of the present invention, in addition to the first aspect, a light emitting element and a first Peltier element for absorbing or generating heat to the light emitting element are built-in. A light emitting element module having a first temperature, a signal light portion displaced in accordance with a physical quantity, and a reference light portion not displaced with respect to the physical quantity; and a physical quantity detection sensor facing the signal light portion of the physical quantity detection sensor. An emission end is disposed with a gap therebetween, and the emitted light of the light emitting element is guided to irradiate the signal light portion, and reflected light from the signal light portion is incident and guided for signal light. An optical fiber and an emission end are arranged at a predetermined gap from the reference light unit of the physical quantity detection sensor, guide the emitted light of the light emitting element to the reference light unit, and irradiate the reference light unit, and Light reflected from The reference light optical fiber, and the light emitted from the light emitting element is branched into the signal light optical fiber and the reference light optical fiber, and the signal light from the signal light portion guided by the signal light optical fiber. A first optical fiber coupler that guides the reflected light; and a waveguide that guides the light emitted from the light emitting element branched by the first optical fiber coupler to the reference light optical fiber and branches the light emitted from the light emitting element into a driver for the light emitting element. A second optical fiber coupler that guides reflected light from the reference light portion guided by the reference light optical fiber, and a signal light portion guided by the first optical fiber coupler. A signal detection photodetector that receives reflected light and converts it into a measurement signal according to the physical quantity, and a thermal expansion of the reference light portion due to a temperature change amount of the physical quantity detection sensor and the reference light optical fiber. Yo A reference signal light detector for receiving reflected light corresponding to the displacement via the reference light optical fiber and the second optical fiber coupler and converting the reflected light into a reference signal; A driver light detector for receiving light emitted from the light emitting element branched for a driver and converting the light into a driver signal for the light emitting element, the light emitting element module, the first optical fiber coupler, and the second optical fiber Optical component temperature holding for mounting optical components such as a coupler, the signal detection photodetector, the reference signal photodetector, and the driver signal photodetector and holding a predetermined second temperature by a second Peltier element The measurement data V _ref (T) (T is the temperature of the physical quantity detection sensor) of the reference signal converted by the reference attachment photodetector and the reference signal photodetector is converted into initial data V at a predetermined constant temperature T _{0. The} calibration value F _{ref <T 0>} (T) calculated from the value normalized by dividing by _ref (T ₀ ) is made to correspond to the memory address of the temperature conversion area, and the physical quantity data at that temperature is recorded. with initial data V _sig (P ₀ of the measurement data V _sig (P, T) of the converted the measured signal by the signal detecting photodetector to a predetermined constant physical quantity P _0, at a predetermined constant temperature T ₀ ,
The calibration coefficient calculated from the standardized value of the measurement signal obtained by dividing by T ₀ ) and the value obtained by dividing by the standardized value of the reference signal is F _{norm <P0, T0>} (P, T) is allocated to a memory address of an area to be converted into a physical quantity, storage means for storing a converted value of a physical quantity corresponding to the memory address in a physical quantity conversion table, and measurement data V _ref (T ) _Is divided by the initial data V _ref (T ₀ ), and F _{ref <T 0>} (T) corresponding to the standard value obtained from the measured data V _sig (P, T) of the actually measured measurement signal. F _{norm <P 0, T0>} (P _{norm <P 0, T0>} (P ₎ corresponding to a value obtained by dividing the standard value obtained by dividing by the initial data V _sig (P ₀ , T ₀ ) by the standard value of the reference signal. , T) and a control circuit for reading a physical quantity from the physical quantity conversion table based on Therefore, it is possible to provide a physical quantity detection device using an optical fiber that achieves the effect of the invention described in claim 7 and requires only one access to the storage unit and can realize higher speed.

According to the ninth aspect of the present invention, the first step of causing the light emitting element to emit light while maintaining the light emitting element at a predetermined first temperature by the first Peltier element built in the light emitting element module; Built-in module and second
An optical component holding a second temperature by a Peltier element A first optical fiber coupler attached to a temperature holding attachment member branches light emitted from the light emitting element into an optical fiber for signal light and an optical fiber for reference light. The optical fiber for signal light irradiates the light emitted from the light emitting element with a gap facing the signal light portion of the physical quantity detection sensor that is displaced according to the physical quantity, and reflects the reflected light from this signal light portion. A second step of passing through the first optical fiber coupler, and reflecting the reflected light from the signal light section passing through the first optical fiber coupler via the signal light optical fiber to the optical component temperature holding attachment member. A third step of receiving light with the attached photodetector for signal detection and converting it into a measurement signal corresponding to the physical quantity;
The light emitted from the light emitting element branched from the signal light optical fiber to the reference light optical fiber by the optical fiber coupler is attached to the optical component temperature holding attachment member.
An optical fiber coupler branches off the light for reference light and the light for driver so that the emitted light for reference light is not displaced from the optical fiber for reference light with respect to the physical quantity. A fourth step of making the reflected light from the reference light section incident and passing through the second optical fiber coupler; and transmitting the reference light passing through the second optical fiber coupler via the reference light optical fiber. A fifth step of receiving the reflected light from the optical part with a reference signal photodetector attached to the optical component temperature holding attachment member and converting the reflected light into a reference signal; And receiving the emitted light of the light emitting element branched by the photodetector for a driver signal and converting it into a signal for driver of the light emitting element. The optical components such as a plastic and a photodetector are held at a predetermined temperature by a mounting member for holding the optical components at a predetermined temperature. As a result, the effects of the temperature of the optical components can be almost completely eliminated, and the physical quantity at high temperatures utilizing the heat resistance, which is the advantage of optical fibers, can be stably maintained. A physical quantity detection method using a measurable optical fiber can be provided.

According to the tenth aspect of the present invention,
The optical fiber for signal light and the optical fiber for reference light have a numerical aperture N.P. A having a large A. A ≧
Since 0.25 is used, it is possible to provide a physical quantity detection device using an optical fiber that can eliminate the influence of the fluctuation of the light source and the bending of the optical fiber as the optical transmission line. According to the eleventh aspect of the present invention, the signal fiber optical fiber and the reference light optical fiber that are hardly bent are used, so that an optical fiber that can provide the same effect as that of the tenth aspect is provided. Can be provided.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a physical quantity detection device using an optical fiber according to a first embodiment of the present invention.

FIG. 2 is a flowchart illustrating a processing procedure at a stage preceding a CPU in a physical quantity detection method using an optical fiber according to the first embodiment of the present invention.

FIG. 3 is a flowchart illustrating a processing procedure at a subsequent stage of a CPU in a physical quantity detection method using an optical fiber according to the first embodiment of the present invention.

FIG. 4 is a block diagram showing a configuration of a physical quantity detection device using an optical fiber according to a second embodiment of the present invention.

FIG. 5 is a flowchart showing a processing procedure at a preceding stage of a CPU in a physical quantity detection method using an optical fiber according to a second embodiment of the present invention.

FIG. 6 is a flowchart showing a processing procedure at a subsequent stage of a CPU in a physical quantity detection method using an optical fiber according to a second embodiment of the present invention.

FIG. 7 is a block diagram illustrating a configuration of a physical quantity detection device using an optical fiber according to a third embodiment of the present invention.

FIG. 8 is a temperature dependence characteristic diagram of the linear expansion coefficient of the INCONEL 718 constituting the physical quantity detection sensor of the physical quantity detection device using the optical fiber of FIG.

9 is a characteristic diagram showing a temperature change at a temperature of 0 to 600 ° C. of the Young's modulus of the INCONEL 718 constituting the physical quantity detection sensor of the physical quantity detection device using the optical fiber of FIG.

10 shows a signal light portion and a reference light portion of a physical quantity detection sensor of the physical quantity detection device using the optical fiber of FIG.
FIG. 7 is a graph showing the reflected light intensity characteristics with respect to a gap G at room temperature in the case of using NEL718.

11 is a characteristic diagram showing reflected light intensity with respect to pressure at room temperature of a physical quantity detection sensor of the physical quantity detection device using the optical fiber of FIG.

12 is a calibration function obtained by dividing a reference signal output at a temperature T of a physical quantity detection sensor according to the physical quantity detection device using the optical fiber of FIG. 1 by a reference signal output at a constant temperature T ₀ and calibrating from a normalized value; FIG. 9 is a characteristic diagram showing a relationship between F _{ref <T0>} (T) and temperature.

13 standardizes the ratio of the measurement signal of the physical quantity P at the temperature T of the physical quantity detection sensor applied to the physical quantity detection device using the optical fiber of FIG. 1 to the measurement signal of the physical quantity P ₀ at the constant temperature T ₀ . Function F _{sig <P0, T0>} (P,
It is a characteristic view which shows the example of T).

14 shows a function F _{ref <T0>} (T) and a function F applied to the physical quantity detection device using the optical fiber of FIG.
_{sig <P0, T0>} Function F obtained from the ratio of (P, T)
FIG. 9 is a characteristic diagram illustrating an example of _{norm <P0, T0>} (P, T).

FIG. 15 is a sectional view showing a temperature analysis model of a physical quantity detection sensor applied to the physical quantity detection device using the optical fiber of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Light emitting element module 2 Light emitting element 3 1st Peltier element 4 Thermal resistance 5 1st temperature sensor 6 1st temperature control 7 Light emitting element driver 8 Optical component temperature holding attachment member 9 2nd Peltier element 10 2nd temperature sensor 11th 2 Temperature control 12 Optical fiber for signal light 12a, 16a, 16b, 16c Optical fiber 13 First optical fiber coupler 14, 21 Optical connector 15 Physical quantity detection sensor 15a Signal light section 15b Reference light section 16 Reference light optical fiber 17 Signal detection Photodetector 18 first amplifier 19 second optical fiber coupler 20 photodetector for driver signal 22 photodetector for reference signal 23 second amplifier 24 A / D converter 25 ROM 26 CPU 27 D / A converter 28 display 29 analog output 30 control circuit

Continued on front page F term (reference) 2F055 AA40 BB20 CC02 DD20 EE31 FF02 2F065 AA06 AA09 BB01 CC00 EE02 FF44 FF46 FF70 GG07 GG12 GG01 JJ01 LL02 NN02 PP22 QQ03 QQ17 QQ18 QQ23 QQ26 QQ42

Claims (11)

[Claims] 1. A light emitting element module having a built-in light emitting element and a first Peltier element for absorbing or generating heat to the light emitting element and maintaining a predetermined first temperature, and a signal light section displaced according to a physical quantity. And a physical quantity detection sensor having a reference light portion that is not displaced with respect to the physical quantity, and an emission end is arranged with a gap facing the signal light portion of the physical quantity detection sensor, and guides light emitted from the light emitting element. And irradiates the signal light portion, and emits the signal light optical fiber that reflects and reflects the light from the signal light portion to enter and guide the signal light portion, and the reference light portion of the physical quantity detection sensor with a predetermined gap therebetween. An optical fiber for a reference light, the end of which is arranged to guide the emitted light of the light emitting element to irradiate the reference light part, and to receive and guide the reflected light from the reference light part; and the light emitting element. The emitted light of the above signal light A first optical fiber coupler that branches into an optical fiber and the reference light optical fiber, and guides reflected light from the signal light portion guided by the signal light optical fiber; and the first optical fiber coupler. The emitted light of the light emitting element branched in the above is guided to the reference light optical fiber, and is branched for the driver of the light emitting element, and from the reference light section guided by the reference light optical fiber. A second optical fiber coupler for guiding the reflected light of the first optical fiber coupler, and a signal for receiving the reflected light from the signal light portion guided by the first optical fiber coupler and converting the reflected light into a measurement signal corresponding to the physical quantity A photodetector, the reflected light corresponding to the displacement due to the thermal expansion of the reference light unit due to the temperature change amount applied to the physical quantity detection sensor and the reference light optical fiber, and the reference light optical fiber and the A reference signal photodetector for receiving light via two optical fiber couplers and converting it into a reference signal; and receiving light emitted from the light emitting element branched for the driver of the light emitting element by the second optical fiber coupler. A photodetector for a driver signal, which converts the light into a driver signal of the light emitting element, the light emitting element module, the first optical fiber coupler,
The second optical fiber coupler, the signal detection photodetector,
An optical component temperature holding mounting member for mounting optical components such as the reference signal photodetector and the driver signal photodetector and maintaining a predetermined second temperature by a second Peltier element. A physical quantity detection device using an optical fiber, characterized in that: 2. A light-emitting element module having a built-in light-emitting element and a first Peltier element for absorbing or generating heat to the light-emitting element and maintaining a predetermined first temperature, and a signal light section displaced according to a physical quantity. And a physical quantity detection sensor having a reference light portion that is not displaced with respect to the physical quantity, and an emission end is disposed with a gap facing the signal light portion of the physical quantity detection sensor, and guides light emitted from the light emitting element. And irradiates the signal light portion and emits the reflected light from the signal light portion with a predetermined gap between the signal light optical fiber and the reference light portion of the physical quantity detection sensor. An optical fiber for a reference light, the end of which is arranged to guide the emitted light of the light emitting element to irradiate the reference light part, and to enter and guide the reflected light from the reference light part; and the light emitting element. The emitted light of the above signal light A first optical fiber coupler that branches into an optical fiber and the reference light optical fiber; and a signal light that guides light emitted from the light emitting element branched by the first optical fiber coupler to the signal light optical fiber. A second optical fiber coupler for guiding reflected light from the signal light section guided by the optical fiber, and a reference light optical fiber for emitting light emitted from the light emitting element branched by the first optical fiber coupler. A third optical fiber coupler that guides the reflected light from the reference light section guided by the reference light optical fiber while branching the light for the driver of the light emitting element; A signal detection photodetector that receives reflected light from the signal light section guided by the optical fiber coupler and converts the reflected light into a measurement signal corresponding to the physical quantity; the physical quantity detection sensor and the reference light; A reference signal for receiving reflected light corresponding to displacement due to thermal expansion of the reference light portion due to a temperature change amount applied to the fiber via the reference light optical fiber and the third optical fiber coupler and converting the reflected light into a reference signal; A photodetector for a driver, a photodetector for a driver signal for receiving light emitted from the light emitting element branched for the driver of the light emitting element by the third optical fiber coupler and converting the light to a signal for driver of the light emitting element; The light emitting element module, the first optical fiber coupler,
The second Peltier device is mounted with optical components such as the second optical fiber coupler, the third optical fiber coupler, the signal detection photodetector, the reference signal photodetector, and the driver signal photodetector. A physical quantity detection device using an optical fiber, comprising: an optical component temperature holding attachment member that holds a predetermined second temperature according to (1). 3. The light emitting element module is maintained at the first temperature by controlling the first Peltier element by a first temperature controller based on a temperature detected by a first temperature sensor provided therein. The physical quantity detection device using an optical fiber according to claim 1. 4. The optical component temperature holding attachment member controls the second Peltier element by a second temperature controller based on a temperature detected by a second temperature sensor provided at a predetermined position. The physical quantity detection device using an optical fiber according to claim 1, wherein the physical quantity detection device is maintained at a temperature. 5. The light emitting device according to claim 1, wherein the light emitting device driver automatically emits light with a constant light amount based on a driver signal of the light emitting device converted by the driver signal light detector. A physical quantity detection device using the optical fiber described in the above. 6. The physical quantity detection sensor is a pressure sensor, and has a diaphragm portion facing an emission end of the signal light optical fiber, and a rigid portion facing the reference light optical fiber. A physical quantity detection device using the optical fiber according to any one of claims 1 to 5. 7. A light-emitting element module having a built-in light-emitting element and a first Peltier element for absorbing or generating heat to the light-emitting element and maintaining a predetermined first temperature, and a signal light section displaced in accordance with a physical quantity. And a physical quantity detection sensor having a reference light portion that is not displaced with respect to the physical quantity, and an emission end is disposed with a gap facing the signal light portion of the physical quantity detection sensor, and guides light emitted from the light emitting element. And irradiates the signal light portion and emits the reflected light from the signal light portion with a predetermined gap between the signal light optical fiber and the reference light portion of the physical quantity detection sensor. An optical fiber for a reference light, the end of which is arranged to guide the emitted light of the light emitting element to irradiate the reference light part, and to enter and guide the reflected light from the reference light part; and the light emitting element. The emitted light of the above signal light A first optical fiber coupler that branches into an optical fiber and the reference light optical fiber, and guides reflected light from the signal light portion guided by the signal light optical fiber; and the first optical fiber coupler. The emitted light of the light emitting element branched in the above is guided to the reference light optical fiber, and is branched for the driver of the light emitting element, and from the reference light section guided by the reference light optical fiber. A second optical fiber coupler for guiding the reflected light of the first optical fiber coupler, and a signal for receiving the reflected light from the signal light portion guided by the first optical fiber coupler and converting the reflected light into a measurement signal corresponding to the physical quantity A photodetector, the reflected light corresponding to the displacement due to the thermal expansion of the reference light unit due to the temperature change amount applied to the physical quantity detection sensor and the reference light optical fiber, and the reference light optical fiber and the A reference signal photodetector for receiving light via two optical fiber couplers and converting it into a reference signal; and receiving light emitted from the light emitting element branched for the driver of the light emitting element by the second optical fiber coupler. A photodetector for a driver signal, which converts the light into a driver signal of the light emitting element, the light emitting element module, the first optical fiber coupler,
The second optical fiber coupler, the signal detection photodetector,
An optical component temperature holding mounting member for mounting optical components such as the reference signal photodetector and the driver signal photodetector and maintaining a predetermined second temperature by a second Peltier element; The measured data V _ref (T) (T is the temperature of the physical quantity detection sensor) of the reference signal converted by the photodetector is converted to the initial data V _{ref of the} reference signal at a predetermined constant temperature T _0.
Calibration coefficient F corresponding to the value normalized by dividing by (T ₀ )
_{ref <T0>} (T) is stored, and at the same time, the measurement data V _sig (P,
T) (where P is a physical quantity) is a predetermined constant physical quantity P ₀ , and the initial data V _sig (P ₀ , T ₀ ) of the measurement signal at a predetermined constant temperature T _0.
F _{sig <P0, T0>} corresponding to the value normalized by dividing by
Storage means for storing a function F _{norm <P0, T0>} (P, T) corresponding to a value obtained by dividing (P, T) by the calibration coefficient _{Fref <T0>} (T); The signal photodetector and the initial value data V _ref (T ₀ ) and V _sig (P ₀ ,
T ₀ ) and the measured value data V _ref (T) and V _sig (P, T) are read and normalized, respectively, and the normalized values and the function F _{ref <T 0>} (T) stored in the storage means are read. And the temperature T is calculated from the ratio of the standardized measurement signal to the standardized reference signal and the calibration coefficient F stored in the storage means.
calculating means for calculating a temperature-compensated physical quantity P from _{norm <P0, T0>} (P, T). 8. A light-emitting element module having a built-in light-emitting element and a first Peltier element for absorbing or generating heat to the light-emitting element and maintaining a predetermined first temperature, and a signal light section displaced according to a physical quantity. And a physical quantity detection sensor having a reference light portion that is not displaced with respect to the physical quantity, and an emission end is arranged with a gap facing the signal light portion of the physical quantity detection sensor, and guides light emitted from the light emitting element. And irradiates the signal light portion and emits the reflected light from the signal light portion with a predetermined gap between the signal light optical fiber and the reference light portion of the physical quantity detection sensor. An optical fiber for a reference light, the end of which is arranged to guide the emitted light of the light emitting element to irradiate the reference light part, and to enter and guide the reflected light from the reference light part; and the light emitting element. The emitted light of the above signal light A first optical fiber coupler that branches into an optical fiber and the reference light optical fiber, and guides reflected light from the signal light portion guided by the signal light optical fiber; and the first optical fiber coupler. The emitted light of the light emitting element branched in the above is guided to the reference light optical fiber, and branched for the driver of the light emitting element, and from the reference light section guided by the reference light optical fiber. A second optical fiber coupler for guiding the reflected light of the first optical fiber coupler, and a signal for receiving the reflected light from the signal light portion guided by the first optical fiber coupler and converting the reflected light into a measurement signal corresponding to the physical quantity A photodetector; and a reflected light corresponding to a displacement due to thermal expansion of the reference light portion due to a temperature change amount of the physical quantity detection sensor and the reference light optical fiber. A reference signal photodetector for receiving light via an optical fiber coupler and converting it into a reference signal; and receiving light emitted from the light emitting element branched for a driver of the light emitting element by the second optical fiber coupler. A driver signal photodetector for converting a driver signal of the light emitting element, the light emitting element module, the first optical fiber coupler,
The second optical fiber coupler, the signal detection photodetector,
An optical component temperature holding mounting member for mounting optical components such as the reference signal photodetector and the driver signal photodetector and maintaining a predetermined second temperature by a second Peltier element; Measurement data V _ref (T) of the reference signal converted by the photodetector (T is the temperature of the physical quantity detection sensor)
_Is divided by the initial data V _ref (T ₀ ) at a predetermined constant temperature T ₀ to calculate a calibration value F _{ref <T 0>} (T) calculated from a normalized value.
Is associated with a memory address of a temperature conversion area, physical quantity data at that temperature is recorded, and measurement data V _sig (P, T) of the measurement signal converted by the signal detection photodetector is stored. _Is divided by the initial data V _sig (P ₀ , T ₀ ) at the predetermined constant physical quantity P ₀ and the predetermined constant temperature T ₀ , and the standardized value of the measurement signal is further standardized as the reference signal. The calibration coefficient calculated from the value obtained by dividing by the value is allocated to the memory address of the area for converting F _{norm <P0, T0>} (P, T) to a physical quantity, and the converted value of the physical quantity corresponding to the memory address In a physical quantity conversion table, and F _{ref <} corresponding to a standard value obtained by dividing actually measured reference signal measurement data V _ref (T) by initial data V _ref (T ₀ ). _T0> and (T), the actual measured measured signal measurement data V _sig (P, T) F a standard value obtained by dividing the initial data _{V sig (P 0, T 0} ), further corresponding to a value obtained by dividing the standard value of the reference signal _{norm <P 0, T0>} (P,
And T) a control circuit for reading a physical quantity from the physical quantity conversion table based on T). 9. A first step in which a light emitting element is kept at a predetermined first temperature by a first Peltier element built in the light emitting element module to emit light, and a second Peltier element holds the light emitting element module. Optical component for holding the second temperature The light emitted from the light emitting element is branched into a signal light optical fiber and a reference light optical fiber by a first optical fiber coupler attached to a temperature holding attachment member, and the signal light The light emitted from the light emitting element is radiated by an optical fiber with a gap opposed to the signal light portion of the physical quantity detection sensor which is displaced according to the physical quantity, and the reflected light from the signal light portion is incident to the first light source. A second step of passing through an optical fiber coupler; and a mounting member for maintaining the optical component temperature, the reflected light from the signal light section having passed through the first optical fiber coupler via the signal light optical fiber. A third step of receiving light with the attached photodetector for signal detection and converting it into a measurement signal corresponding to the physical quantity; and converting the signal light optical fiber to the reference light optical fiber by the first optical fiber coupler. The emitted light of the branched light emitting element is split into a reference light and a driver by a second optical fiber coupler attached to the optical component temperature holding attachment member, and the emitted light for the reference light is referred to above. The second optical fiber coupler irradiates the second optical fiber coupler by irradiating a reference light portion of the physical quantity detection sensor which does not displace with respect to a physical quantity from the optical fiber for light with a gap therebetween, and receiving reflected light from the reference light portion. A fourth step of passing the reflected light from the reference light section, which has passed through the second optical fiber coupler via the reference light optical fiber, to a reference signal attached to the optical component temperature holding attachment member. Light test A fifth step of receiving light by the output device and converting it into a reference signal; and receiving light emitted by the light emitting element branched for a driver by the second optical fiber coupler with a photodetector for driver signal and receiving light of the light emitting element. A physical quantity detecting method using an optical fiber, comprising: a sixth step of converting the signal into a driver signal. 10. The optical fiber for signal light and the optical fiber for reference light have a numerical aperture N. A having a large A. The physical quantity detection device using an optical fiber according to any one of claims 1, 2, 7, and 8, wherein A ≧ 0.25. 11. The optical fiber according to claim 1, wherein the optical fiber for signal light and the optical fiber for reference light are hardly bent.
A physical quantity detection device using the optical fiber described in the paragraph.