JPH03152427A - Color discriminating device - Google Patents

Abstract

PURPOSE:To integrate a photosensor having sensitivity to a specific wavelength without increasing the area of a detecting element and thereby to enable discrimination of color free from an error by providing the photosensor on an end face of a fluorescent beam-condensing plate and by disposing it on the incidence side of light. CONSTITUTION:A yellow substance cut to be 5 mm long, 5 mm wide and 1 mm thick is used for a fluorescent beam-condensing plate 1. The fluorescent beam-condensing plate 1 has an absorption peak in the vicinity of 470 mmu in the region of a visible light beam and emits a fluorescent light of a peak 520 mmu from an end face. As for photosensors 4 and 5, an Si photodiode is used. The photosensor 4 is fitted to the central part of one end face of the fluorescent beam-condensing plate 1, while the photosensor 5 is fitted to the central part on the exit side of the light of the fluorescent beam-condensing plate 1. Analog signals obtained from the photosensors 4 and 5 are converted into digital signals by an A/D converter after they are amplified, and these signals are processed by a personal computer. A short-wavelength-side component of an incident light 7 is absorbed by the fluorescent beam-condensing plate 1, turned into the fluorescent light and detected by the photosensor 4 on the end face part. Therefore, even a minute incident light can be measured without an error.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a color identification device, and more particularly to a color identification device whose detection area can be made smaller than that of conventional color identification devices.

<Conventional technology> Color identification devices are used for color management of products in various industries, automatic sorting machines,
It is used for color adjustment of video cameras, etc. In the prior art, two methods have been used in color identification devices.

The first method, as shown in Fig. 5, consists of three photodiodes (9) and (9') on one transparent substrate (8).
and (9') are placed adjacent to each other, and a filter (10) of three primary colors of red (R), green (G), and blue (B) is provided on each photodiode. The incident light is separated by three primary color filters and guided to the RS GS B photodiode. Therefore, by determining the output ratio of these three photodiodes, colors including intermediate colors can be identified. The second method uses a semiconductor pnp structure as shown in FIG. 6, and specifically, two photodiodes with different junctions [electrode (17) / pS -S
1/electrode (technique 8) and electrode (18)/n-s j
It has a structure in which /p-3I/ electrodes (19) are stacked. This method utilizes the difference in spectral sensitivity between a photodiode with a shallow junction and a photodiode with a deep junction on the light incident side, and performs color discrimination based on the output ratio of these two photodiodes.

<Problems to be Solved by the Invention> However, the color identification device of the first method (Fig. 5) described above uses three photodiodes (9), (9) that detect the three primary colors of R, G, and B. ') and (9') are arranged on a plane, so if the incident light is not uniformly irradiated, there is a drawback that errors occur in color identification. In other words, in the case of minute incident light such as light guided through an optical fiber, it has been impossible to distinguish colors. In addition, in the color identification device of the second method described above (Fig. 6), since the detection parts are arranged vertically, color identification is possible even with minute incident light, but since there are only two photodiodes, This method had a disadvantage in that its color discrimination ability was inferior to that of the color discrimination device of method 1 (Fig. 5).

An object of the present invention is to provide a color identification device that eliminates the above-mentioned drawbacks of conventional color identification devices.

<Means for Solving the Problems> The present invention uses a fluorescent light condensing plate to achieve the above object. A fluorescent light condensing plate is made by adding a fluorescent substance to a transparent glass plate or plastic plate, or by forming a thin film containing a fluorescent substance on a transparent substrate. It absorbs light in a wavelength band and emits light (fluorescence) that is different from that wavelength band. The fluorescent light emitted here undergoes repeated total reflection inside the fluorescent condensing plate and is guided to the end face. In other words, the light intensity in the absorption wavelength band can be measured at the end face of the fluorescent light condensing plate, and the light in other wavelength bands is transmitted through the fluorescent light condensing plate.

The inventors focused on the above-mentioned function, and by placing a light sensor (4) on the end face of a fluorescence condensing plate (1) on the light incident side, it was possible to identify without increasing the area of the detection part. We were able to create a color identification device by integrating optical sensors that are sensitive to wavelengths. The configuration of the color identification device of this invention varies depending on the application, but even for simple color identification, R, G,
Two optical sensors that detect two colors out of 83 primary colors are required as a minimum, and the order is a fluorescent condenser plate (1) with optical sensors (4) provided on the end face from the light incident side, and optical sensors (5). Place it in However, from this point on, the sensor (5)
) It is also possible to install it on the end face of a fluorescent light condensing plate (2) whose absorption wavelength is different from that of the fluorescent light collecting plate (2), and in this case, it becomes a transparent color identification device because a part of the light is transmitted. Ideally, the order in which the fluorescent light collecting plates are stacked is arbitrary, but since commonly used organic fluorescent materials have light absorption bands on the shorter wavelength side, the fluorescent light collecting plates with shorter absorption wavelengths should be stacked in any order. It is desirable to arrange them in order starting from the light plate'. For strict color discrimination applications, R,
Three optical sensors are required to detect the three primary colors of G and B. In this case, the configuration of the color identification device is as follows: fluorescent light condensing plates (1) and (2) absorb two of the three primary colors from the light incident side.
), optical sensors (4) and (5) installed on each end face, and optical sensor (6) are arranged in this order. however,
The sensor (6) can also be installed on the end face of the fluorescent condenser plate (3) that absorbs the remaining one color among the three primary colors, and in this case it becomes a transparent color identification device.

The fluorescent light condensing plates are arranged in the same manner as in the case of using the two optical sensors described above, such that the fluorescent light condensing plate having absorption on the short wavelength side is located on the light incident side. Specifically, the fluorescence condensing plate is arranged so that the absorption wavelengths are in the order of B and GSR. As the optical sensor used in the color identification device of the present invention, any sensor can be used as long as it has sensitivity in the visible light region, that is, between 380 nm and 780 nm. However, since the intensity of light on the long wavelength side is attenuated each time it passes through the fluorescence concentrator, it is desirable to use a Si photodiode that has sufficient sensitivity even in the long wavelength region. Note that when manufacturing the color identification device of the present invention, it is necessary to make the refractive index around the fluorescent light condensing plate smaller than the refractive index of the transparent substrate material used for the fluorescent light concentrating plate. It is.

Effect〉 The short wavelength side component of the incident light is absorbed by the fluorescence condensing plate,
It is converted into fluorescence and detected by the optical sensor on the end surface.

On the other hand, the long wavelength side component is transmitted through the fluorescence condensing plate and detected by the optical sensor. Therefore, by taking the ratio of the signals of these optical sensors, the color of the incident light can be identified. With this method, even in strict color identification applications using a large number of optical sensors, the area of the detection section does not increase, so even minute amounts of incident light can be measured without error.

<Example> Hereinafter, the present invention will be described in detail based on the drawings.

FIG. 1 shows an example of the color identification device of the present invention.
(1) is a fluorescence condensing plate, (4) and (5) are optical sensors,
(7) indicates incident light.

As the fluorescent light condensing plate (1), use a commercially available yellow one with a length of 5 mm.
It was used by cutting it into pieces 5 mm wide and 1 mm thick. This fluorescence condensing plate (1) has an absorption peak around 47 nm in the visible light region, and emits fluorescence with a peak at 520 nm from the end face. Si photodiodes are used as the optical sensors (4) and (5), with (4) attached to the center of one end face of the fluorescence condenser, and (5) attached to the center of the light exit side of the fluorescence condenser. Installed each. Analog signals obtained from each optical sensor were amplified and then converted into digital signals by an A-D converter so that they could be processed by a personal computer.

Next, a color discrimination test of incident light was conducted using the above device. First, a tungsten lamp was used as the light source for the incident light (7), and the resulting light was converted into a parallel light beam with a diameter of 2 mm using a lens, and then entered the center of the fluorescent light condensing plate (1) of the color identification device described above. . At this time, optical sensors (4) and (5)
) was taken as the measurement result using white light. Next, a red filter was placed in front of the fluorescence condensing plate (1), and the signal output obtained at this time was taken as the measurement result using red light. Similarly, measurement results using green light and measurement results using blue light were obtained. For the measurement results obtained in this way, the levels of the signals for each sensor were first adjusted using a personal computer, and then the light intensity ratio of the sensors was determined. This former process is because the signal level of the optical sensor (4) provided on this end surface is lower than that of the optical sensor (5) due to the low conversion efficiency of the fluorescent light condensing plate (l,), and This is done because the Sl photodiode has spectral sensitivity characteristics.

Specifically, a coefficient is determined so that the output value for white light is equal between the optical sensor (4) and the optical sensor (5), and that value is applied to the signal output value obtained for each color of incident light. The hanging was done by matching. FIG. 7 shows the results of measurement using the color identification device of this embodiment, expressed as a light amount ratio for each sensor.

It can be seen that since the absorption wavelength of the fluorescence condenser plate (1) is close to the spectrum of blue light, the photosensor (4) is highly sensitive to blue incident light and can be distinguished from green and red incident light. Therefore, if these output ratios are stored in a personal computer, the color of incident light can be identified. However, if the light source is changed to another type, it is necessary to retake the reference data for that light source.

Figure 2 (circle 15) shows an example of the color identification device of this invention.
(1) and (2) are fluorescent light condensing plates, (4) and (5)
) indicates the optical sensor, and (7) indicates the incident light. As the fluorescence condensing plate (1), the same one as in Example 1 was used.

As the fluorescent light condensing plate (2), a commercially available orange one was cut into pieces of 5 mm in length, 5 mm in width, and 1 mm in thickness. This fluorescent light condensing plate (2) is 530n in the visible light region.
It has an absorption peak near m, and emits fluorescence with a peak at 580 nm from the end face. Sl photodiodes were used as the optical sensors (4) and (5), and were attached to the center portions of the end faces of the fluorescent light condensing plates (1) and (2), respectively.

Signals from each optical sensor were processed in the same manner as in Example 1. Note that the signal levels of the optical sensors (4) and (5) are the same as in Example 1 because the conversion efficiency of the fluorescence condensing plates (1) and (2) is different, and the 31 photodiode has spectral sensitivity characteristics. It is necessary to match. FIG. 8 shows the results of a color discrimination test of incident light using the above-mentioned apparatus, expressed as a light m ratio for each sensor.

The absorption wavelength of the fluorescent light concentrating plate (1) is blue light, and the absorption wavelength of the fluorescent light condensing plate (2) is blue light.
) has an absorption wavelength close to the spectrum of green light, so the optical sensor (4) had high sensitivity for blue and the optical sensor (5) had high sensitivity for green. Therefore, as in Example 1, the color of the incident light could be identified.

Point 11 Figure 3 shows an example of the color identification device of this invention.
(1) and (2) are fluorescent condensing plates, (4), (5) and (6) are optical sensors, and (7) is incident light.

The same fluorescent light collecting plates (1), (2) as in Example 2 were used. The optical sensors (4), (5) and (
As for 6), an S1 photodiode is used, and the central part of the end face of the fluorescent light condensing plates (1) and (2), and the fluorescent light condensing plate (
2) were attached to the center of the light exit side. Signals from each optical sensor were processed in the same manner as in Examples 1 and 2. FIG. 9 shows the results of a color discrimination test of incident light using the above-mentioned apparatus, expressed as a light m ratio for each sensor. In addition to the results of Example 2, optical sensors (6
), the sensitivity was higher in red.

Therefore, the color of the incident light could be identified more precisely than in Examples 1 and 2.

Figure 4 shows an example of the color identification device of the present invention.
(1), (2) and (3) are fluorescent light condensing plates, (4),
(5) and (6) show the light sensor, and (7) shows the incident light. As the fluorescent light condensing plates (1) and (2), the same ones as in Examples 2 and 3 were used. Fluorescent condensing plate (3
) is a commercially available red one with a length of 5 mm and a width of 5 mm.
It was used by cutting it into pieces with a thickness of 1 mm. This fluorescent light collecting plate 3
has an absorption peak around 590 nm in the visible light region, and emits fluorescence with a peak at 640 nm from the end face.

S1 photodiodes were used as the optical sensors 4), (5) and (6), and were attached to the center of the end faces of the fluorescent condensing plates (1), (2) and (3), respectively. The signals from each optical sensor were processed in the same manner as in Examples 1.2 and 3. FIG. 10 shows the results of a color discrimination test of incident light using the above-mentioned apparatus, expressed as a light amount ratio for each sensor. Similar to the results of Example 3, sensor 3 had high sensitivity in red. Therefore, as in Example 3, the color of the incident light could be identified.

<Effects of the Invention> The color identification device of the present invention has the following advantages.

(a) Since a fluorescence condensing plate is used on the light incident surface, the detection units can be arranged vertically, so while maintaining the same discrimination ability as the conventional first method color discrimination device, The area can be reduced to about 1/3.

(b) Colors can be identified without error even when the incident light is minute.

(c) Since the detection section can be entirely composed of a fluorescent light condensing plate, transmitted light can be used.

[Brief explanation of the drawing]

1, 2, 3, and 4 are cross-sectional views of color identification devices of embodiments 1.2.3 and 4 of the present invention, respectively. 5 and 6 are cross-sectional views of a conventional color identification device. FIGS. 7, 8, 9, and 10 show the light amount ratios for each sensor measured in Examples 1, 2, 3, and 4 of the present invention, according to the color of the incident light. be. (1), (2), (3)... Fluorescent condensing plate (4),
(5), (6) ... Optical sensor (7)
・・・・・・・・・ Incident light (8)
......Glass substrate (9), (9'), (18), (19 Photodiode color filter Lead frame back electrode amorphous SI Transparent electrode 81 substrate insulating film) ... Electrode No. Figure 5 Figure 6 Figure 1 Engraving of the drawing (no changes in content) ↓7 Figure 2 ↓7 2" ZZZZZ7 koE5 Figure 4 Figure 7 Figure 8 Joining light mouth sensor (4) Mouth sensor ( 5) Figure 9 Tip sensor (4) Incident light tip sensor (5) Flash sensor (6) Figure 10 Procedural amendment (method) As attached (no change in content)

Claims (1)

[Claims] 1. The outermost surface on the light incident side consists of a fluorescence condensing plate (1), which absorbs light in a specific wavelength band in the incident light (7) and collects the emitted fluorescence. The color of the incident light can be identified from the ratio of the signal measured by the optical sensor (4) provided on the end surface and the signal measured by the optical sensor (5) of the light transmitted through the fluorescent condensing plate (1). Characteristic color identification device. 2. The color identification device according to claim 1, wherein the optical sensor (5) is provided on the end face of the fluorescent condensing plate (2) whose absorption wavelength is different from that of the outermost surface. 3. The incident light (7) is calculated from the ratio of the signal measured by the optical sensor (6) of the light transmitted through the fluorescent condensing plates (1) and (2) and the signal measured by the optical sensor (4) and (5). 3. The color identification device according to claim 2, wherein the color identification device identifies colors of . 4. Claim 3, characterized in that the optical sensor (6) is provided on the end face of the fluorescent light condensing plate (3), which has an absorption wavelength different from that of the fluorescent light condensing plates (1) and (2). color identification device.