JPH01217241A - Reflectance and transmittance measuring device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an apparatus for measuring the reflectance and transmittance of an object to light.

[Prior Art] FIG. 3 is a schematic diagram of a conventional reflectance and transmittance measuring device of this type. In the figure, a light source 1 and an object to be measured 2
are spaced apart from each other, and the object to be measured 2 is placed relative to the light source 1.
is placed so that its surface is vertical, but light source 1
Measures are taken to prevent the light waves radiated from directly reaching the measuring object 2.

And, approximately halfway between the light source 1 and the object to be measured 2, and
Mirrors 3a and 3b are arranged in symmetrical positions, and the light source 1
The object to be measured 2 is irradiated by reflecting the light emitted from the object 2 from opposite directions at the same angle of incidence. Also,
A lens 4 and a light receiving element 5 are provided between the light source 1 and the object to be measured 2, and the lens 4 condenses the light reflected in the direction perpendicular to the light irradiation surface of the object to be measured 2. or convert this into an electrical signal. On the other hand, a lens 6 and a light receiving element 7 are provided on the back side of the object to be measured 2 when viewed from the light source 1.
Of the light transmitted through the object to be measured 2, the light traveling in a direction perpendicular to the light irradiation surface is collected by the lens 6, and the light receiving element 7 converts it into an electrical signal.

Further, the electric signals of the light receiving elements 5 and 7 are taken into the light quantity detection circuit 8, where they are converted into signals corresponding to the reflectance and transmittance, and the reflectance and transmittance are displayed on the display circuit 9.

[Problems to be Solved by the Invention] The conventional reflectance and transmittance measuring devices described above have a configuration in which the light emitted from a single light source is guided to the surface of the object to be measured using a mirror. Therefore, there are problems in that the optical path length becomes longer and the device becomes larger, and at the same time, it is difficult to narrow down the optical path width and delicate positioning is required for each of the mirrors, lenses, and light-receiving elements.

There is also the problem that it is not possible to compensate for fluctuations in measured values that occur when the amount of light changes due to fluctuations in power supply voltage, fluctuations in characteristics over time, and the like.

An object of the present invention is to provide a reflectance and transmittance measuring device that can realize miniaturization of the device and at the same time eliminate the need for delicate positioning.

Another object of the present invention is to provide a reflectance and transmittance measuring device that allows correction of fluctuations in measured values due to fluctuations in the amount of light from a light source.

[Means for Solving the Problems] The reflectance and transmittance +1111 constant device according to the present invention guides light emitted from a single light source to the surface of an object to be measured using two optical fibers, and , so that the optical axes of the two optical fibers intersect at the surface of the constant object so that the light guided by these □ optical fibers illuminates the surface of the object to be measured from mutually opposite directions at the same angle of incidence. This is what was placed.

In addition, the amount of reflected light that is vertically reflected from the surface of the object to be measured and the amount of transmitted light that is perpendicularly transmitted to the back surface of the object to be measured are guided to a light receiving element using an optical fiber, and based on the output of this light receiving element, the reflectance and the The transmittance is set at 1lllll.

Furthermore, in order to correct fluctuations in the measured value due to fluctuations in the light amount of the light source, a light amount detection circuit that detects the light amount of the light source and a measured value correction circuit that corrects the measured value based on the output of this light amount detection circuit are provided. It is equipped with the following.

[Function] If two optical fibers are used to guide the light from the light source as described above, the light will simply be emitted regardless of the relative position of the object to be measured and the light source or the length of the optical fiber. Because all you have to do is align the direction and position of the end of the optical fiber on the other side.
Compared to conventional devices that use mirrors to illuminate the surface of the object to be measured, the device can be made more compact, and delicate positioning is no longer necessary.

In addition, he not only guided light to the surface of a constant object, but also
4 - By guiding reflected light and transmitted light to the light-receiving element through optical fibers, it is possible to achieve further miniaturization compared to conventional devices that use lenses, and at the same time eliminates the need for delicate positioning. Ru.

Furthermore, by being equipped with a light intensity detection circuit and a measured value correction circuit, even if the light intensity of the light source changes due to power fluctuations or characteristic fluctuations, reflectance and transmittance can always be accurately measured. Device reliability can be improved.

[Embodiment] FIG. 1 is a schematic diagram of an embodiment of the present invention, and the same reference numerals as in FIG. 3 indicate the same elements. And mirrors 3a and 3b in Fig. 3
% Lenses 4 and 5 are removed, and instead, two optical fibers LOA and TAB are used to guide the light emitted from light source 1 to the surface of the object to be measured, and optical fiber LC1 is used.
a, IOb is arranged so that the optical axis of the object to be measured 2 crosses the surface of the nJ constant object 2 from the opposite direction at a predetermined angle of incidence, and the reflected light from the surface of the object to be measured 2 is is guided to the light-receiving element 5 using an optical fiber.
It is constructed so that the transmitted light from the l11 constant object 2 is guided to the light receiving element 7 using an optical fiber 12.

In this case, as long as only the ends of the optical fibers loa and lOb on the object to be measured 2 side face in a predetermined direction, measurement will not be affected even if the position of the light source 1 changes; As long as the end of .2 on the side of the object to be measured 2 is perpendicular to the surface of the object to be measured, the other end may be anywhere. Therefore, the position of the light receiving element 5.7 can be arbitrarily selected. be able to.

Here, as a specific method for measuring reflectance and transmittance, first, a standard white board with a reflectance of 100% is attached in place of the object 2 to be measured, and the amount of reflected light is measured. Next, the amount of transmitted light is measured with this standard white plate removed. next,
After attaching the object 2 to be measured and measuring the amount of reflected light and the amount of transmitted light, reflectance and transmittance are measured by calculation.

FIG. 2 is a schematic diagram of another embodiment of the present invention, and in the figure, the same reference numerals as in FIG. 1 indicate the same elements. Further, the light emitted from the light source 1 is newly guided to the light receiving element 14 using the optical fiber 13, and the light amount detection circuit 15 measures the light amount of the light source 1 based on the output of the light receiving element 14. When the output of this light amount detection circuit 15 and the output of the light amount detection circuit 8 that measures the reflected light amount and transmitted light amount are input to the measured value correction circuit 16, the 41 fixed value correction circuit 1G or Reflectance.

The difference from FIG. 1 is that variations in each measured value of transmittance are corrected and applied to the display circuit 9.

According to this configuration, reflectance and transmittance can be measured with high precision even if there are fluctuations in power supply voltage, characteristic fluctuations over time, etc.

Note that a photo-I transistor may be used as the light-receiving elements 5, 7°]4 constituting the above embodiment, and a DC amplifier that amplifies the output of the light-receiving element and a DC amplifier that amplifies the output of the light-receiving element as the light amount detection circuits 8, 15. A-D converting to digital signal
It may be configured with a converter and a microprocessor that calculates reflectance and transmittance based on the converted digital data. Furthermore, as the measured value correction circuit 16, an amplifier whose gain can be controlled may be used, or a microprocessor may be used. When using a microprocessor, a light amount detection circuit 8. 5 and the function of the measured value correction circuit 16 may be provided in one microprocessor. [Effects of the Invention] The reflectance and transmittance measuring device of the present invention is constructed as described above. As a result, the following effects can be achieved.

By guiding the light from the light source using two optical fibers,
It is only necessary to align the direction and position of the end of the optical fiber on the side from which light is emitted, which allows the device to be made more compact and eliminates the need for delicate alignment.

By guiding the reflected light and the transmitted light to the light receiving element using optical fibers, the size of the -layer can be reduced, and at the same time alignment can be facilitated.

In addition, by providing a correction circuit for the variation in measured values due to variations in the amount of light from the light source, the accuracy and reliability can be improved.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of one embodiment of the reflectance and transmittance measuring device of the present invention, FIG. 2 is a schematic diagram of another embodiment, and FIG.
The figure is a schematic configuration diagram of a conventional reflectance and transmittance measuring device. 1... Light source 2... Measured object 5,
7.14... Light receiving element 8,15... Light amount detection circuit 9
...Display circuits 10a, 10b, 11, 12.13-=optical fiber 16
...Measurement value correction circuit inventor Cloth material Kiyoshi Yasuhara Kozo Yojima Hakuo Patent applicant Mitsubishi Rayon Co., Ltd.

Claims (3)

[Claims] (1) By guiding the light emitted from a single light source,
The surface of the object to be measured is irradiated from opposite directions at the same angle of incidence, and the reflectance is measured based on the signal corresponding to the amount of reflected light that is vertically reflected from the surface of the object to be measured, and the amount of transmitted light that is perpendicularly transmitted to the back surface is measured. In this reflectance and transmittance measurement device, the light emitted from the light source is guided to the surface of the object to be measured using two optical fibers, and the A reflectance and transmittance measuring device, characterized in that the optical axes of optical fibers are arranged so as to intersect on the surface of the object to be measured. (2) guiding the reflected light from the surface of the object to be measured and the transmitted light to the back surface to a light receiving element via optical fibers, respectively;
2. The reflectance and transmittance measuring device according to claim 1, wherein the reflectance and transmittance are measured based on the output signal of the light receiving element. (3) Claim comprising: a light amount detection circuit that detects the light amount of the light source; and a measured value correction circuit that corrects a variation in the measured value due to a change in the light amount of the light source based on the output of the light amount detection circuit. 3. The reflectance and transmittance measuring device according to 1 or 2.