JP2018124133A - Photochromic detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a simple and compact size detector that can quantitatively measure a color change of a photochromic substance when ultraviolet light is emitted and when not emitted.SOLUTION: The detector comprises: a light source device (3) including an ultraviolet LED (11), a red LED (12), a green LED (13) and a blue LED (14) in a specific emission wavelength; a photodetector (15) including a photoelectric conversion element detecting light intensity of light emitted from the light source device (3) to a medium and reflected from or transmitting through the medium; and a microcomputer (5) that, based on light intensity of each color light detected by the photodetector when ultraviolet light is not emitted, but red light, green light and blue light are individually emitted, and light intensity of each color light detected when the red light, the green light and the blue light are individually emitted while the ultraviolet light is emitted, calculates a numerical value corresponding to a change in light intensity of each color light when ultraviolet light is emitted and when not emitted, and causes a display unit to display it.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a photochromic detection device that detects a photochromic substance applied or impregnated in a medium such as paper or a light transmitting body.

  Photochromic materials with a dimming function that reversibly changes color (reflectance and transmittance of visible light) by ultraviolet light irradiation are dimming sunglasses and light modulation elements that reduce glare in outdoor direct sunlight. It is used as a first optical material, and as a printing material such as a security ink or a coating agent that can be switched between non-display / display of specific characters and marks by non-irradiation / irradiation of ultraviolet light.

As typical photochromic substances, spiropyran compounds, spirooxazine compounds, naphthopyran compounds, fulgide compounds, diarylethene compounds, and the like have been developed.
However, for the dimming function of photochromic materials, characteristics such as color, color density and color development / decoloration speed suitable for the application are required. Therefore, various derivatives and compounds having a new molecular skeleton have been developed. Yes.

  Therefore, for newly developed photochromic substances, existing photochromic substances, or resin materials obtained by mixing these photochromic substances with a polymer substrate at a predetermined mixing ratio, the color of the ultraviolet light when not irradiated and when irradiated There is a demand for quantitative measurement of change characteristics.

In addition, when using photochromic materials for printing materials such as security inks, the color change characteristics of the printing materials when not irradiated with ultraviolet light and when irradiated differ depending on the composition of the photochromic material. Not only can the presence / absence of a specific printed figure to be displayed be discriminated / confirmed, but also the measured value can be used as security information by quantitatively measuring the color change characteristics.
That is, by comparing the numerical value of the color change characteristic measured in advance for a specific photochromic substance used as security ink with the numerical value of the color change characteristic measured for the photochromic substance used in the printed material to be detected. Since the identity of the photochromic substance can be determined to determine the authenticity of the printed matter, the measurement value of the color change characteristic can be included as security information.

Incidentally, a spectrophotometer is generally used to measure the color change characteristics.
This spectrophotometer has a pre-spectroscopy method and a post-spectroscopy method. In the pre-spectrometry method, light emitted from a white light source is divided into a predetermined narrow band light by a spectroscope such as a bandpass filter or a prism. A sample to be measured is irradiated, and the light intensity of reflected light or transmitted light from the object to be measured is measured for each band light with a single sensor.
The post-spectral method irradiates a sample to be measured with light emitted from a white light source, and divides the reflected or transmitted light into predetermined band light using a spectroscope such as a bandpass filter or a prism. Then, for each band light, the light intensity is measured by a plurality of sensors.
With either method, the light intensity of each band light included in the light reflected or transmitted through the sample can be measured, and if there is any color change in the sample, the respective light intensity changes. It is possible to quantitatively measure the change characteristics.

In these methods, since the accuracy of measurement increases as the number of bands to be divided increases, a white (broadband) light source is used as the light source, and many band-pass filters are used.
In order to increase the photoelectric conversion current of the photodetector, this type of narrow-band bandpass filter is required to have a low light transmittance in the wavelength band to be cut and a high light transmittance in the wavelength band to be passed. Such a filter is very expensive because it must be manufactured for each wavelength band using a multilayer deposition technique.

  In addition, as a simple spectrophotometer that does not use a white (broadband) light source or a band-pass filter, RGB LEDs (light emitting diodes) that irradiate the sample with red, green, and blue light are used. It is known that the light intensity of reflected light from a sample is detected by a single sensor for each color light (Patent Documents 1 and 2).

However, in any of the spectrophotometers described above, the visible light reflected or transmitted from the sample is split into monochromatic light of a predetermined wavelength band, and the light intensity is measured for each monochromatic light, thereby measuring each wavelength band. Since it measures the light intensity distribution, it is often not equipped with an ultraviolet light source.
Even if an ultraviolet light source is provided, the ultraviolet light source is intended to extend the measurement wavelength region from the visible light region to the ultraviolet light region. Even if the intensity can be measured, it is not possible to measure the light intensity at the time of non-irradiation and irradiation of each band of light obtained by separating visible light into monochromatic light.
Therefore, depending on the spectrophotometer, it is not possible to measure the color change characteristics of the photochromic substance when it is not irradiated with ultraviolet light, and conventionally, an optical surface plate is installed in a dark room, and then, An optical system capable of performing spectroscopic measurement similar to that of a spectrophotometer was assembled, and a color change characteristic of the photochromic material had to be measured using a large-scale apparatus provided with a separate ultraviolet light source.

JP-A-63-75524 Japanese Patent Laid-Open No. 11-218447

  Therefore, the present invention is a simple, small and inexpensive photochromic capable of quantitatively measuring the color change characteristics of the photochromic substance when not irradiated with ultraviolet light and without irradiation, without using a large-scale apparatus as described above. Providing a detection device is a technical problem.

  In order to solve this problem, the present invention provides a photochromic detection device for detecting a photochromic substance coated or impregnated on a medium such as paper or a light transmissive body, wherein ultraviolet light, red light, green A light source device provided with an ultraviolet LED, a red LED, a green LED and a blue LED having a specific emission wavelength for irradiating light and blue light, and light reflected from or transmitted to the medium from the light source device A photodetector provided with a photoelectric conversion element for detecting intensity; and the photodetector when the light source device individually irradiates red light, green light and blue light without irradiating the medium with ultraviolet light. The light detector detects when the red light, the green light and the blue light are individually irradiated with the red light, the green light and the blue light while the ultraviolet light is irradiated on the medium. Detected red Based on the light intensity of each of green light and blue light, a microcomputer that calculates numerical values corresponding to changes in the light intensity of each color light during non-irradiation of ultraviolet light and during irradiation and displays the numerical values on a display It is characterized by comprising.

According to the photochromic detection device of the present invention, the light source device is provided with the ultraviolet light LED in addition to the red light LED, the green light LED, and the blue light LED, and the light of each color light at the time of non-irradiation and irradiation of the ultraviolet light. Since the color change characteristics of photochromic materials can be measured quantitatively based on the intensity, an optical system is built on an optical surface plate installed in a dark room as in the past, or an expensive narrowband bandpass filter is installed. Without being used, it can be manufactured in a small size and at a low cost.
In addition, the identity of the photochromic material can be determined by comparing the numerical data obtained by measuring the color change characteristics of a known photochromic material in advance with the numerical data obtained by measuring the color change characteristics of an unknown photochromic material. If numerical data on known photochromic substances is stored in a database, the photochromic substance can be specified based on the measured numerical values.

Explanatory drawing which shows an example of the photochromic detection apparatus which concerns on this invention. II-II line sectional drawing of the photometry part. The flowchart which shows the process sequence of a microcomputer. (A) is an external appearance perspective view which shows another Example, (b) is explanatory drawing which shows the internal structure of a measurement probe, (c) is cc sectional view taken on the line of (b).

  This example is a photochromic detection device for detecting a photochromic substance coated or impregnated on a medium such as paper or a light transmissive body, and irradiates the medium with ultraviolet light, red light, green light and blue light. A light source device provided with an ultraviolet light LED, a red light LED, a green light LED, and a blue light LED having a light emission wavelength, and a photoelectric conversion element that detects the light intensity of light reflected from or transmitted through the medium from the light source device. The provided light detector and the red light, green detected by the light detector when the light source device individually irradiates red light, green light and blue light without irradiating the medium with ultraviolet light. The light intensity of each of light and blue light and the red light and green light detected by the photodetector when the medium is irradiated with red light, green light and blue light while irradiating ultraviolet light. And each of the blue light Based on the intensity, it calculates a value corresponding to the change in light intensity of each color light when irradiated at the time of non-irradiation of ultraviolet light, and a microcomputer for displaying the numerical value on the display.

Here, if an ultraviolet light cut filter that absorbs or reflects ultraviolet light contained in the light incident on the photodetector is arranged, even if a photodetector having sensitivity in the ultraviolet light region is used, The influence of ultraviolet light can be eliminated.
As numerical values corresponding to the change in light intensity calculated by the microcomputer, for example, a logarithmic conversion value of the light intensity of each color light when ultraviolet light is not irradiated, and a logarithmic conversion value of the light intensity of each color light when ultraviolet light is irradiated The ratio of the change in light density calculated by the difference between the values, or the logarithm conversion value of the light intensity of each color light when not irradiated with ultraviolet light and the logarithmic conversion value of the light intensity of each color light when irradiated with ultraviolet light The calculated light density change rate or the like may be used.
In addition, in order to drive and control the light source device, the ultraviolet light LED is switched between a non-lighting state and a lighting state by a predetermined start operation, and the red light LED, the green light LED, and the blue light LED are individually turned on in each state. If the microcomputer is equipped with a sequence control means that individually stores the light intensity of each color light during non-irradiation of ultraviolet light and during irradiation, for example, all measurements are performed with only one operation of pressing the start switch. The measurement result can be displayed.

Furthermore, if the light source device, the light detection unit, the microcomputer, and the display unit are integrated into the apparatus main body, the size can be reduced to a portable level.
Furthermore, such a device main body is formed in a handy type, and the light emitted from each LED arranged on the device main body side is guided to the measurement probe connected via the bundle fiber to the medium. Light emitting ends of a plurality of light projecting light guides (optical fibers) to be irradiated and light receiving light guides (optical fibers) that receive light reflected or transmitted by the medium and guide the light to the photodetector. If the light incident end is arranged, there is an advantage that the measurement probe can be easily measured by placing it on the place where measurement is desired.

  A photochromic detection apparatus 1 shown in FIGS. 1 and 2 is used to detect a photochromic substance applied or impregnated in a medium such as paper or a light transmissive body, and is used by being mounted on the medium. The light source device 3, the photodetector 4, the microcomputer 5 that performs drive control of the light source device 3 and predetermined calculation processing, and the liquid crystal display plate 6 as a display for displaying the calculation processing result are provided.

An observation window 7 is formed on the bottom surface of the apparatus main body 2 so as to overlap an arbitrary detection site on the medium, and a photometric unit 8 is formed therein.
The photometric unit 8 is formed with four inclined surfaces 9 having a truncated pyramid shape inside, and an ultraviolet light LED 11, a red light LED 12, a green light LED 13, and a blue light LED 14 having a specific light emission wavelength to be the light source device 3. It is attached to the observation window 7 so as to irradiate ultraviolet light, red light, green light and blue light in an equiangular manner from diagonally above in the front-rear and left-right directions.
Further, the photodetector 4 is provided with an ultraviolet light cut filter 16 that absorbs or reflects ultraviolet light on the incident surface of the photodiode 15, and an observation window for detecting the light intensity of the light reflected by the medium. 7 is disposed on the ceiling surface 10 immediately above the center.
The photometric unit 8 is a light shielding space so that light does not enter from the outside in a state where the observation window 7 is overlaid and closed on the medium.

The microcomputer 5 includes a program for performing drive control of the LEDs 11 to 14 of the light source device 3, a program for performing predetermined arithmetic processing based on the light intensity signal output from the light detector 4, and various data necessary for measurement. A memory for temporarily storing data being measured and storing data is provided. When the main switch 20 is turned on, a standby state is established. When the start switch 21 is turned on, processing is executed according to the program.
Then, each of red light, green light and blue light detected by the photodetector 4 when the light source device 3 individually irradiates the medium with ultraviolet light without irradiating red light, green light and blue light. Light intensity, and red light, green light, and blue light detected by the photodetector 4 when the medium is irradiated with red light, green light, and blue light while being irradiated with ultraviolet light. Based on the intensity, a numerical value corresponding to a change in the light intensity of each color light during non-irradiation of ultraviolet light and during irradiation is calculated and displayed on the liquid crystal display panel 6.

  The liquid crystal display panel 6 includes a red light data display portion 6R, a green light data display portion 6G, and a blue light data display portion 6B. Each of the display portions 6R, 6G, and 6B includes an ultraviolet light non-irradiation data display portion 17 and an ultraviolet light. Numerical data is displayed in a 3 × 3 table format provided with a light irradiation time data display section 18 and a difference or ratio data display section 19.

  FIG. 3 is a flowchart showing the processing procedure of the microcomputer 5. When the start window 21 is turned on with the main switch 20 turned on with the observation window 7 of the photochromic detector 1 placed on an arbitrary place of the medium to be measured. The processing shown in FIG. 3 starts to be executed.

First, it is confirmed in step STP1 that the ultraviolet LED 11 is turned off, the index n is set to 0, the process proceeds to steps STP2 to STP4, and the red light measurement process is executed.
Here, the red light LED 12 is turned on in step STP2, the process proceeds to step STP3, and the reflected light intensity PRn (n = 0) of the red light from the medium is measured by the photodetector 4, and stored in a predetermined storage area. Thereafter, the red LED 12 is turned off in step STP4.

Subsequently, it transfers to step STP5-7 and a green light measurement process is performed.
Here, the green light LED 13 is turned on in step STP5, the process proceeds to step STP6, and the reflected light intensity PGn (n = 0) of green light from the object to be measured is measured by the photodetector 4, and stored in a predetermined storage area. After storing, the green light LED 13 is turned off in step STP6.

Furthermore, it transfers to step STP8-10 and a blue light measurement process is performed.
Here, the blue light LED 14 is turned on in step STP8, the process proceeds to step STP9, the reflected light intensity PBn (n = 0) of the blue light from the object to be measured is measured by the photodetector 4, and stored in a predetermined storage area. After storing, the blue light LED 14 is turned off in step STP10.

In step STP11, it is determined whether or not n = 1. If n = 1, in order to measure the reflected light intensity at the time of ultraviolet light irradiation, the process proceeds to step STP12 to turn on the ultraviolet LED 11, and the index n = 1, the process returns to step STP2, and each color light measurement process of steps STP2 to STP10 is executed to measure the reflected light intensity PRn (n = 1), PGn (n = 1), and PBn (n = 1) of each color light. .
Thereby, each color reflected light intensity PR ₀ , PG ₀ , PB ₀ when not irradiated with ultraviolet light and each color reflected light intensity PR ₁ , PG ₁ , PB ₁ when irradiated with ultraviolet light are measured.

If it is determined in step STP11 that n = 1, the process proceeds to step STP13, and the light intensity PR ₀ , PG ₀ , PB ₀ , PR ₁ , PG ₁ , of each color light at the time of non-irradiation and irradiation of ultraviolet light. Based on PB ₁ , a numerical value corresponding to the change in light intensity of each color light during non-irradiation with ultraviolet light and during irradiation is calculated. In this example, the change amount ΔDR of the light density value is used as a numerical value corresponding to the change in light intensity. , ΔDG, ΔDB, or the change rate of the light density value.

The change amounts ΔDR, ΔDG, and ΔDB of the light density values are defined as the difference between the light density values of the respective color lights when the ultraviolet light is not irradiated and irradiated, but the light intensity PR ₀ of each color light when the ultraviolet light is not irradiated. , PG ₀ , PB ₀ logarithmically converted values and the light intensity PR ₁ , PG ₁ , PB ₁ logarithmically converted values of each color light at the time of ultraviolet light irradiation are equivalent to the difference, and are calculated by the following equation.
ΔDR = log (PR ₀ ) −log (PR ₁ )
ΔDG = log (PG ₀ ) −log (PG ₁ )
ΔDB = log (PB ₀ ) −log (PB ₁ )

The change rate of the light density value is defined as the ratio of the light density of each color light when not irradiated with ultraviolet light and the light intensity PR ₀ , PG ₀ , PB ₀ of each color light when not irradiated with ultraviolet light. The ratio is a ratio of the logarithm conversion value to the logarithm conversion value of the light intensity PR ₁ , PG ₁ , PB ₁ of each color light when irradiated with ultraviolet light, and the transmission is performed.
log (PR ₀ ) / log (PR ₁ )
log (PG ₀ ) / log (PG ₁ )
log (PB ₀ ) / log (PB ₁ )
Or
log (PR ₁ ) / log (PR ₀ )
log (PG ₁ ) / log (PG ₀ )
log (PB ₁ ) / log (PB ₀ )

In step STP14, the logarithm conversion values log (PR ₀ ), log (PG ₀ ), log (PB ₀ ) of the light intensities PR ₀ , PG ₀ , and PB ₀ of each color light reflected by the medium when no ultraviolet light is irradiated. Logarithmically converted values log (PR ₁ ), log (PG ₁ ), log (PB ₁ ) of each color reflected light intensity PR ₁ , PG ₁ , PB ₁ of each color light reflected by the medium when irradiated with ultraviolet light, light The change amount ΔDR, ΔDG, ΔDB of the density value or the change rate of the light density value is displayed on the liquid crystal display panel 6 and the process is terminated.

  In addition, the process of steps STP1 to 11 switches the ultraviolet light LED 11 to a non-lighting state and a lighting state by a start operation, and individually lights the red light LED 12, the green light LED 13, and the blue light LED 14 in each state, This is a sequence control means for individually storing the light intensity of each color light during non-irradiation of ultraviolet light and during irradiation.

The above is one configuration example of the present invention, and the operation thereof will be described.
When detecting the photochromic substance applied to the medium, the observation window 7 is placed on the detection portion of the medium, and the start switch 21 is turned on with the main switch 20 turned on.

Thereby, the sequence control which lights each LED11-14 is performed.
First, the red light LED 12, the green light LED 13, and the blue light LED 14 are individually turned on sequentially without turning on the ultraviolet light LED 11, and the respective light intensities of the respective color lights reflected by the medium when the ultraviolet light is not irradiated are detected. (Steps STP1 to STP10).
Next, with the ultraviolet light LED turned on (step STP12), the red light LED 12, the green light LED 13, and the blue light LED 14 are individually turned on sequentially, and each of the color lights reflected by the medium when irradiated with the ultraviolet light is emitted. The light intensity is detected (steps STP2 to 10).
When the detection of the light intensity is completed, a numerical value corresponding to the change is calculated based on the detected light intensity of each color light, and is displayed on the liquid crystal display panel 6 (steps STP12 to 14).

As described above, in this example, all the measurements are performed and the measurement results are displayed by only one operation of pressing the start switch 21.
Also, the numerical value corresponding to the change in light intensity is calculated as the change amount ΔDR, ΔDG, ΔDB of the light density value or the change rate of the light density value, and the numerical values are red light, green light, blue light, which are the three primary colors of light. Since each color light is displayed on the liquid crystal display panel 6, it is possible to quantitatively measure what color change has occurred due to ultraviolet light irradiation.
Therefore, the optical system can be simply and compactly manufactured at low cost without using an optical system on an optical surface plate installed in a dark room as in the prior art or using an expensive narrow-band bandpass filter.

Furthermore, numerical data obtained by measuring the color change characteristics of a known photochromic substance in advance is stored in a microcomputer, and the numerical data of the color change characteristics measured for an unknown photochromic substance is compared with the numerical data stored in advance. By doing so, the identity of the photochromic substance can be determined.
Furthermore, if numerical data on known photochromic substances is stored in a database, the photochromic substance can be specified based on the measured numerical values.

FIG. 4 shows another embodiment of the present invention. In addition, about the part which is common in FIGS. 1-2, the same code | symbol is attached | subjected and detailed description is abbreviate | omitted.
The photochromic detection device 31 of this example is configured by connecting a measurement probe 33 to a device main body 32.
In the apparatus main body 32, an optical connector 35 is formed on an upper part of a handy-type portable casing 34, and each of the LEDs 11 to 14 serving as the light source device 3 and the photodiode 15 serving as the photodetector 4 are included in the optical connector 35. It is arranged.

The measurement probe 33 is formed in a pen shape, and a bundle fiber 36 serving as a light guide is extended from the rear end portion thereof and connected to the optical connector 35, and a photometry portion 38 having an opening 37 at the tip is formed. Thus, when the opening 37 is pressed against the medium to be measured, no light enters from the outside.
In the photometry unit 38, an end face 39 of the bundle fiber 36 serving as a light projecting / receiving unit is arranged toward the opening 37, and a central fiber group 45 is connected to the photodetector 4 as a light receiving light guide, The surrounding fiber groups are randomly divided into four, and the respective fiber groups 41 to 44 are connected to the LEDs 11 to 14 of the light source device 3 as light projecting light guides.
As a result, the light emitted from the LEDs 11 to 14 is guided to the respective optical fiber groups 41 to 44, irradiated from the end face 39 of the bundle fiber 36 toward the medium, reflected by the medium, and incident on the light projecting / receiving unit 38. The light is guided to the photodetector 4 by the fiber group 45, and the light intensity is detected.

  Therefore, when the start button 21 is pressed in a state where the opening 37 of the photometry unit 38 is applied to an arbitrary measurement site of the medium, each LED 11 to 14 is driven by a built-in microcomputer (not shown) as in the first embodiment. Controlled, each color light can be individually irradiated to the medium when ultraviolet light is not irradiated and irradiated, and the light intensity of each color light reflected by the medium can be measured individually, and based on this, the light intensity A numerical value corresponding to the change in the light density is calculated, for example, as a change amount of the light density value, and the result is displayed on the liquid crystal display panel 6.

  In the description of the above embodiment, the case where the change amount and the change rate of the light density value are calculated and displayed as the numerical value corresponding to the change of the light intensity has been described. The amount of change or the rate of change may be displayed, or may be calculated based on a predetermined arithmetic expression.

  Furthermore, in each of the embodiments, the type that detects the light reflected by the medium has been described. However, the type that detects the light that has passed through the medium may be used. The light incident surface of the light guide connected to the photodetector 4 is arranged on the side opposite to the light exit surface of the light guide connected to the LEDs 11 to 14 of the light source device 3. Just place it.

  The present invention can be applied to a use of a photochromic detection device that quantitatively measures a color change characteristic of a photochromic substance when ultraviolet light is not irradiated and when irradiated.

DESCRIPTION OF SYMBOLS 1 Photochromic detection apparatus 2 Apparatus main body 3 Light source apparatus 4 Photo detector 5 Microcomputer 6 Liquid crystal display panel 7 Observation window 11 Ultraviolet light LED
12 Red LED
13 Green light LED
14 Blue light LED
15 Photodetector 16 Ultraviolet light cut filter

Claims (6)

A photochromic detection device for detecting a photochromic substance applied or impregnated in a medium such as paper or a light transmissive body,
A light source device provided with an ultraviolet light LED, a red light LED, a green light LED and a blue light LED of a specific emission wavelength for irradiating the medium with ultraviolet light, red light, green light and blue light;
A photodetector provided with a photoelectric conversion element that detects the light intensity of light reflected from or transmitted through the medium from the light source device;
Each of red light, green light and blue light detected by the photodetector when the light source device individually irradiates red light, green light and blue light without irradiating the medium with ultraviolet light. Light intensity and each light of red light, green light and blue light detected by the photodetector when individually irradiating red light, green light and blue light while irradiating the medium with ultraviolet light And a microcomputer for calculating a numerical value corresponding to a change in light intensity of each color light during non-irradiation of ultraviolet light and during irradiation based on the intensity and displaying the numerical value on a display. Photochromic detection device.   A numerical value corresponding to the change in the light intensity is calculated by a difference value between a logarithmic conversion value of the light intensity of each color light when not irradiated with ultraviolet light and a logarithmic conversion value of the light intensity of each color light when irradiated with ultraviolet light. Change in light density calculated by the ratio of the amount of change in light density value or the logarithmic conversion value of the light intensity of each color light when not irradiated with ultraviolet light and the logarithmic conversion value of the light intensity of each color light when irradiated with ultraviolet light The photochromic detection device according to claim 1, which is a rate.   The photochromic detection device according to claim 1, wherein an ultraviolet light cut filter that absorbs or reflects ultraviolet light contained in light incident on the photodetector is arranged.   The microcomputer switches the ultraviolet light LED between a non-lighting state and a lighting state by a predetermined start operation, and individually lights the red light LED, the green light LED, and the blue light LED in each state, thereby preventing the ultraviolet light from being turned off. The photochromic detection apparatus according to any one of claims 1 to 3, further comprising sequence control means for individually storing the light intensity of each color light at the time of irradiation.   The photochromic detection device according to claim 1, wherein the light source device, the light detection unit, the microcomputer, and the display unit are integrally incorporated in a device main body. A measurement probe is connected to the apparatus main body, and the measurement probe guides light emitted from each LED and irradiates the medium with a plurality of light projecting light guides, and reflects or transmits through the medium. The photochromic detection device according to claim 5, further comprising a light receiving light guide that receives received light and guides the light to the photodetector.

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