JPH0194221A - Object state detector - Google Patents

Abstract

PURPOSE:To obtain a small-sized detector having high reliability regardless of the kind of a container receiving an object, by allowing an electromagnetic wave or ultrasonic wave variable in an expanse angle to be incident to an object and detecting the state of the object on the basis of the intensity of the reflected wave from the object. CONSTITUTION:When an electromagnetic wave is allowed to be vertically incident to the surface of a liquid 4 from a light source 2, the intensity I of the reflected light thereof is inversely proportional to the square of the distance L up to the surface of the liquid 4. By this, the reflected light incident to a photodetector 6 is taken out as a photocurrent to be converted to signal voltage and, when this voltage value coincides with a predetermined reference voltage value, it is judged that the distance L becomes a predetermined reference distance L0 and it can be decided that the liquid in a tank becomes a predetermined residual amount. Further, a light projecting lens 3 is moved with respect to the light source 2 and, by regulating the interval (a) between both of them, the expanse angle theta of emitted luminous flux can be set arbitrarily. By this, the intensity I of the reflected light can be made same regardless of the kind of the tank and, when the voltage value becomes the predetermined reference voltage value, it can be judged that the residual amount of the liquid becomes a predetermined value, without regulating the reference voltage value at all.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an object state detector that detects the state of an object, such as kerosene, kerosene, etc., in a fuel tank, for example, whether it is left behind.

[Conventional technology]

Conventionally, 7A of liquids such as Karin and kerosene in tanks
Object state detector that mechanically detects the amount by floating the flow 1 ~ sphere on the liquid surface and using the movement of the float sphere up and down with the liquid surface (in the above example, the object status detector vessels) are commonly used.

[The problem that the invention attempts to solve]

However, in the conventional object state detector as described above, since the flow 1 ~ sphere moves up and down, a movable part is required, which limits the ability to miniaturize the detector itself. Since the detection is performed mechanically, there is a problem in that failures are likely to occur due to rusting of the component parts.

In addition, when it is necessary to determine the remaining amount of liquid, if the tank model is different □, generally the standard from the detector to the liquid level on a predetermined cross plate is different. However, there was a problem in that a dedicated detector had to be made for each type of tank.

The present invention provides an object state detector that is highly reliable and can be miniaturized, and that can be easily adjusted even when the reference distance to the surface of the object, for example, the liquid level, changes. It is an object.

[Means for solving problems]

The present invention provides an electromagnetic wave incident on the object, which includes an input means for making electromagnetic waves or ultrasonic waves incident on the object, and a detection means for detecting the state of the object based on the intensity of the electromagnetic waves or ultrasonic waves emitted from the object. Alternatively, the problems of the prior art described in "-" can be improved by using an object state detector characterized in that the spread angle of ultrasonic waves is variable.

[Operation] In the present invention, electromagnetic waves or ultrasonic waves are applied to the proboscis of the object 1, for example, the liquid surface, and the state of the object, for example, the remaining amount of the liquid, is detected based on the intensity of the electromagnetic waves or ultrasonic waves emitted from the object 1. do. Since the state of the object is detected in a non-contact manner using electromagnetic waves or ultrasonic waves, the detector itself can be made smaller and its reliability can be improved. However, in the present invention, the spread angle of electromagnetic waves or ultrasonic waves incident on the object can be adjusted by, for example, changing the distance between the light source of the input means and the projection lens. Is the seed fi or the base of the object human blood? Even in the case of V-110 chicks or minnows, the remaining amount of the object can be determined using the same method.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a schematic diagram of an embodiment of the object state detector according to the present invention.

The object state detector 1 of this embodiment includes a light source 2 that outputs electromagnetic waves, a projection lens 3 that can arbitrarily set the divergence angle of the emitted light beam of the light source 2, and a light emitted from the object 4, that is, reflected light. It includes a light receiving lens 5 for condensing light and a light receiving element 6 for photoelectrically converting reflected light.

The target Th4 is, for example, a liquid such as gasoline.

Light source 2. Projection lens 3. Light receiving field 5 and light receiving element 6
are arranged on the same optical axis, and the electromagnetic waves are perpendicularly incident on the liquid surface of the object 4 and are reflected. That is, the object state detector 1 shown in FIG. 1 is rotatably attached to a tank (not shown) so that its central axis coincides with the optical axis of the optical system.

Furthermore, in this embodiment, by adjusting the distance between the light source 2 and the projection lens 3, the spread angle θ of the emitted light beam can be adjusted.

FIGS. 2(a) and 2(b) are a side sectional view and a front view of a mechanism for adjusting the distance between the light source 2 and the projection lens 3, respectively.

In FIG. 2, the light source 2 is, for example, a light emitting diode.
- and the distance from the light emitting point 20 of the light source 2 to the front principal point position of the projection lens 3 is a. Light source 2 is attached to fixture 2
1 and the projection lens 3 is attached to the lens bolt 22? -J is being treated. The fitting 2] and the lens holder 22 are screwed together, and by rotating the lens holder 22, the distance a between the light source 2 and the light projecting lens 3 can be changed. Further, an I-shaped member 23 is provided on the fixture 21 in a protruding manner.

The L-shaped member 23 has a hole 24 in which:
A rectangular spring 26 is housed at the tip of the L-shaped member 23 to bias the ball 25 toward the side wall of the lens holder 22. On the other hand, a 7-shaped groove 27 is formed in the side wall of the lens holder 22, and when the lens bolder 22 is rotated a predetermined number of times with respect to the removal tool 21, the pole 25 is fitted into the 7-shaped groove 27, and the lens holder 22 is tightened with more force. It will not turn unless you add . As a result, the amount of extension of the projecting lens 3, that is, the amount of change in the interval a, is
1 and the pitch of the screw that screws together the lens holder 22;
It is determined by the position of the 7-shaped groove 27 in the lens holder 22, and by changing the distance a, the divergence angle θ can be adjusted as described below.

In such a configuration, the intensity of the electromagnetic waves from the light source 2 is ■.

, its spread angle is θ, and the reflectance of the liquid surface is R1.
The distance from to the liquid level is I7. The aperture of the projection lens 3 is d
, the effective diameter of the light-receiving lens 5 is drρ, the intensity I of the reflected light incident on the light-receiving element 6 is [:16-R2・tan" (θ/2):]
----Given as (1). Note that the intensity of the reflected light (2) is the intensity of the reflected light mainly specularly reflected by the surface of the liquid.

In formula (1), I, R, d, and d are constant Orp. Also, assuming that the divergence angle θ is constant while the object state detector is operated in one type of tank, the intensity of the reflected light is f? Ii II I
It changes in inverse proportion to the square of -. As a result, the reflected light incident on the light-receiving element 6 is extracted as a photocurrent, which is converted into a signal voltage in a processing circuit subsequent to the light-receiving element 6, and the distance I- to the liquid surface is determined as a voltage value. When H matches the predetermined reference voltage value, the distance reaches the predetermined reference voltage H
1,, o, and it can be determined that the liquid in the tank has reached a predetermined remaining amount. In this way,
In the object state detector 1 of this embodiment, the height of the liquid level and the remaining amount can be detected in a non-contact manner using electromagnetic waves without using mechanical members such as flow 1 to spheres. can be made smaller and have higher reliability.

By the way, the standard distance I, which is the standard for determining the remaining amount, may differ depending on the type and shape of the tank that houses the liquid.In such cases, the type of tank changes and the standard distance I. changes. By adjusting the reference voltage value for each type of tank in the subsequent processing circuit, it is possible to detect the same remaining liquid level. However, the reflected light intensity ■ is Because it is inversely proportional, if the reference distance 1-o differs by a factor of two or more, the signal voltage will become significantly smaller, and there is a risk that the error in detecting the remaining amount will increase. The remaining amount determination accuracy will differ.

Therefore, in this 11th example, instead of adjusting the reference voltage value, the intensity of the reflected light incident on the light receiving element 6 when the reference pressure M Lo is only the distance to the liquid level is determined by the type of tank. The spread angle θ should be adjusted each time the type of tank changes so that it remains constant. In other words, in order to ensure that the intensity ■ of the reflected light incident on the light receiving element 6 is always constant regardless of the type of tank, in equation (1), the divergence angle θ is changed for each type of tank. , this spread angle θ and the reference pressure ilL. Between jan (θ/2) −1,, o= C1=−-
---Is it necessary to bring about the relationship in (2)? Note that C1 is [■.

・R・ (d − d ) / (16・I)] 1/
It has a constant value of 2rp.

Furthermore, assuming that the focal length of the projecting lens 3 is f and the size of the light emitting point 20 of the light source 2 is negligibly small, the divergence angle θ, the focal length f1 of the projecting lens 3 and the light emitting point 20 are The distance a between the front principal point position of the optical lens 3 and the distance a is tan (θ/2) = C(f a ) d p
/ (2・a-f))・
...The relationship (3) holds true, and it can be seen from equation (3) that in order to adjust the divergence angle θ, it is sufficient to change the interval a.

Therefore, instead of the relationship between the spread angle θ and the reference distance Lo, the distance a and the reference distance. To obtain which relationship, the following equation can be obtained by eliminating the divergence angle θ from equations (2) and (3).

a= (f-d-Lo)/(2,c-t'+a-r,o,-
------- (4) rp Even if the reference distance Lo changes depending on the type of tank, as seen from equation (4), the distance a can be adjusted by moving the projection lens 3 relative to the light source 2. By doing so, it is possible to make the intensity I of the reflected light incident on the light receiving element 6 the same regardless of the type of tank when the liquid reaches a predetermined remaining amount, and the reference voltage value can be set in the subsequent processing circuit. It is possible to determine that a predetermined remaining amount is present when the voltage value reaches a predetermined reference voltage value without making any adjustment.

The distance a between the light emitting point 20 of the light source 2 and the projection lens 3 is adjusted by rotating the lens holder 22 to which the projection lens 3 is attached relative to the tool 21, as described above.

FIGS. 3(a) to 3(C) show the object state detector 1 of this embodiment in three types of tanks 30 and 3 of different sizes.
Fig. 4(a) is a diagram showing the state in which it is attached to 1.32.
3A to 3C are diagrams showing the reflected light intensity ■ obtained by adjusting the interval a in each case of FIGS. 3A to 3C, in which the reference distance Lo is different. In addition, in FIGS. 3(a) to (C), the object state detector 1
− means that the focal length f of the light emitting lens 3 is 10 mm, the aperture d of the light emitting lens 3 is 6 mm, and the effective diameter d of the light receiving lens 5.
, 8 mm.

The intensity Io of the electromagnetic waves from the light source 2 was set to lQmw. In addition, the reflectance R at the liquid surface was set to 0.02. I/■o 0.0
Do not set it to 01. Based on the above values, the constant C1 is ], 8
．． It becomes 97. Furthermore, in FIGS. 3(a) to (C), the reference distance Lo to the liquid level is 200 mm and 50 mm, respectively.
0+nm, 1000mm.

Substituting these values into equation (4), the light emitting point 2 of light 'a2
0 to the front principal point position of the projection lens 3, the distance a is 7.60 mm in the example of FIG.
The example in Figure (b) is 8.881 m, and the example in Figure 3 (C) is 9.41 m. mm, and the divergence angle θ in each case is 10.84° and 4.357°, respectively.

2.It becomes 1.75°. Substituting these values into equation (1) yields a reference pressure of 1 ftL for the remaining amount of liquid to be determined.

The intensity of the reflected light before and after is determined by the fourth
It is determined as shown in Figures (a) to (C).

When the tolerance ε is set to ±5% for the reference distance ■-8 for determining the remaining capacity set in each of Figures 4 (a) to (C), the intensity ■ of the reflected light will vary depending on the three different types. tank 3
0, 31.32, 9.1 to 11,
It falls within the range of 1μW.

On the other hand, the intensity ■ of the reflected light focused on the light receiving element 6F is linearly converted into a photocurrent value in the light receiving element 6, and this photocurrent value is linearly converted into a voltage value in a processing circuit (not shown) or in a subsequent stage. Since it is converted and amplified, the signal voltage as a result of the amplification is proportional to the intensity I of the reflected light and has the same error range regardless of the type of tank. Therefore, by always comparing the signal voltage with a constant reference voltage value, the same determination accuracy can be obtained for any type of tank.

In this way, in this embodiment, it is possible to adjust the spread angle θ by changing the interval a to make the accuracy of determining the remaining amount of liquid the same regardless of the type of tank, or instead of changing the interval a. It is also possible to adjust the divergence angle θ by changing the optical constants of the projection lens 3 itself.

In addition, in the above embodiment, the optical systems of the object state detector 1 are arranged so that they have the same optical axis, and the incident light is incident perpendicularly to the liquid surface, so that the optical paths of the incident light and the reflected light are made to coincide. The light source 2. makes light incident at a predetermined angle that is not perpendicular, and makes the optical path of the incident light and reflected light symmetrical with respect to the central axis of the object state detector. Light emitting lens 3 and light receiving lens 5. The light receiving element 6 and the light receiving element 6 may be arranged on different optical axes. However, in this case as well, the center axis of the object state detector is always kept perpendicular to the liquid level.
, 2- It is necessary to ensure that it is maintained. However, if the optical paths of the incident light and the reflected light are different, it is not suitable for miniaturization and the detection sensitivity decreases compared to the case where the optical paths are the same. It is good to use it only for special applications where optical systems cannot be placed on the same optical axis.

Furthermore, in the above embodiment, the height of the liquid 1, that is, the remaining amount of the liquid, is detected by detecting the intensity of the reflected light from the liquid surface or by detecting the intensity of the transmitted light that has passed through the liquid. It's okay. However, when detecting the intensity of transmitted light, the optical system for the incident light and the optical system for the transmitted light must be installed separately at separate locations, and a simple structure can be used to separate the optical path of the incident light and the optical system of the transmitted light. It is difficult to match the optical path accurately.

Further, although the object 4 is a liquid such as kerosene or kerosene in a fuel tank, it is not limited to a liquid, and may be a granular object such as rice grains in a rice rack, or a solid that wears out during use. Even when the object 4 is granular or solid, the remaining amount and other conditions can be detected in the same manner by using electromagnetic waves with a wavelength appropriate for the object.

Furthermore, the state of the object 4 may be detected not only by electromagnetic waves but also by ultrasonic waves.

〔Effect of the invention〕

As explained in Section 2 below, in the present invention, electromagnetic waves or ultrasonic waves are incident on the object and the state of the object is detected based on the intensity of the electromagnetic waves or ultrasonic waves emitted from the object. It can be made smaller than a mechanical detector, and failures can be reduced. Furthermore, since the spread angle of the electromagnetic waves or ultrasonic waves incident on the target object is variable, even if the standard distance changes depending on the type of container such as a tank containing the target object, it will not remain regardless of the type of container. It can be easily adjusted so that the amount determination accuracy is the same.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the object state detector according to the present invention, and FIGS. 2(a) and 2(b) are side sectional views and front views of a mechanism for adjusting the distance between the light source and the projecting lens, respectively. Figures 3(a) to 3(C) are diagrams showing how the object condition detectors are attached to three types of tanks of different sizes, and Figures 4(a) to 4(c) are diagrams showing how the object condition detectors are attached to three types of tanks of different sizes, respectively. It is a figure which shows the relationship between the distance to a liquid level calculated in the installation state of FIGS. (a) thru|or (C), and reflected light intensity. DESCRIPTION OF SYMBOLS 1...Target state detector, 2...Light source, 3...Light projecting lens, 4...Target, 5...Light receiving lens, 6...
...Light receiving element, a... Distance between light source and light emitting lens, θ
... Divergence angle, Lo... Reference distance Patent applicant
Hamamatsu Photonics Co., Ltd. Representative Patent Attorney Masa Tomari Uemoto -1,6- (a) Distance L (mm) Figure 4 (b) (C)

Claims (1)

[Scope of Claims] 1) An input means for injecting electromagnetic waves or ultrasonic waves into an object, and a detection means for detecting the state of the object based on the intensity of the electromagnetic waves or ultrasonic waves emitted from the object; An object state detector characterized in that the spread angle of incident electromagnetic waves or ultrasonic waves is variable. 2) The divergence angle is changed so that the intensity of the electromagnetic waves or ultrasonic waves to the detection means remains the same even when the reference distance to the object changes. The object state detector described. 3) The object state detector according to claim 1, wherein the divergence angle is adjusted by changing the distance between the light source of the input means and the projection lens.