WO2024085027A1 - Optical device for measurement - Google Patents

Optical device for measurement Download PDF

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Publication number
WO2024085027A1
WO2024085027A1 PCT/JP2023/036817 JP2023036817W WO2024085027A1 WO 2024085027 A1 WO2024085027 A1 WO 2024085027A1 JP 2023036817 W JP2023036817 W JP 2023036817W WO 2024085027 A1 WO2024085027 A1 WO 2024085027A1
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WO
WIPO (PCT)
Prior art keywords
light
light receiving
optical
filter
measurement
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PCT/JP2023/036817
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French (fr)
Japanese (ja)
Inventor
明 小坂
敏 増田
洋 波多野
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コニカミノルタ株式会社
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Publication of WO2024085027A1 publication Critical patent/WO2024085027A1/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J1/00—Photometry, e.g. photographic exposure meter
    • G01J1/02—Details
    • G01J1/04—Optical or mechanical part supplementary adjustable parts
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J3/00—Spectrometry; Spectrophotometry; Monochromators; Measuring colours
    • G01J3/46—Measurement of colour; Colour measuring devices, e.g. colorimeters
    • G01J3/50—Measurement of colour; Colour measuring devices, e.g. colorimeters using electric radiation detectors
    • G01J3/51—Measurement of colour; Colour measuring devices, e.g. colorimeters using electric radiation detectors using colour filters

Definitions

  • This invention relates to an optical measurement device capable of measuring the luminance, chromaticity, etc. of a measurement object such as a display.
  • Patent document 1 proposes a technology that uses a focusing lens system to focus light on a light receiving sensor.
  • Patent Document 1 when attempting to focus light on a small sensor area using a focusing lens system, the number of lenses increases, making the configuration more complex, while the effect is limited.
  • This invention was made to solve these problems, and aims to provide an optical measurement device that can efficiently focus light on a light receiving sensor to improve the S/N ratio.
  • an objective optical system a plurality of types of photoelectric conversion units each receiving only light of a predetermined wavelength range from the light from the objective optical system;
  • a measuring optical device comprising: Each of the photoelectric conversion units is a filter that transmits only light of a predetermined wavelength range using an interference film; a light receiving sensor that receives light transmitted through the filter and whose output is amplified by an amplifier; a compound parabolic concentrator positioned between the filter and the light receiving sensor, for concentrating the light transmitted through the filter onto the light receiving sensor;
  • An optical measuring device comprising: (2) The measurement optical device according to the preceding paragraph 1, wherein the compound parabolic concentrator is formed of a transparent material.
  • a measurement optical device described in the preceding paragraph 1 or 2 which has an optical fiber that splits the light from the objective optical system and guides it to each photoelectric conversion unit, and the area of the exit surface of the split optical fiber is larger than the area of the light incident on the light receiving sensor.
  • each of the photoelectric conversion units has a filter that transmits only light of a predetermined wavelength range by an interference film, and receives the light transmitted through the filter.
  • the device has a light receiving sensor whose output is amplified by an amplifier, and a compound parabolic concentrator located between the filter and the light receiving sensor and which focuses the light transmitted through the filter on the light receiving sensor.
  • the light transmitted through the filter is focused on the light receiving sensor by the compound parabolic concentrator, it is possible to efficiently focus the light even if the sensor area is small. Furthermore, by making the sensor area smaller, it is possible to reduce the capacity of the input section of the amplifier that amplifies the output of the light receiving sensor, and the noise (N) of the amplifier can be reduced, thereby improving the S/N ratio of the measurement optical device.
  • the compound parabolic concentrator is formed from a transparent material, so the light-collecting properties of the compound parabolic concentrator are not impeded.
  • the surface of the compound parabolic concentrator facing the light receiving sensor is flat, and the compound parabolic concentrator and the light receiving sensor are joined by an optical path joining adhesive. Therefore, the light beam emitted from the compound parabolic concentrator can reach the light receiving sensor without being reflected on the surface of the light receiving sensor.
  • the compound parabolic concentrator and the light receiving sensor can be positioned and fixed, preventing fluctuations in the positional relationship between them.
  • the filter is formed by applying an interference film to the incident surface of a parallel plate, making it easy to create and maintain the filter.
  • the filter is formed by applying an interference film to the incident surface of the compound parabolic concentrator. This makes it possible to reduce the distance between the optical system element arranged on the incident side of the compound parabolic concentrator and the compound parabolic concentrator.
  • the light from the objective optical system can be split by optical fibers and guided to each photoelectric conversion unit.
  • the area of the exit surface of the split optical fibers is larger than the area of the light incident on the light receiving sensor, a sufficient amount of light can be incident on the light receiving sensor.
  • FIG. 1 is a block diagram showing the internal configuration of a tristimulus value photoelectric colorimeter, which is an optical measuring device according to an embodiment of the present invention.
  • FIG. 11 is a graph showing the relationship between the capacitance of the input section of each amplifier and noise.
  • FIG. 1 is a diagram for explaining each component of an optical system including a photoelectric conversion unit and a beam splitting member that guides light to the photoelectric conversion unit, where (A) is a diagram viewed from the front, and (B) is a diagram of the photoelectric conversion unit viewed from the light incident side.
  • 1A is a vertical cross-sectional view of the main components of a photoelectric conversion unit
  • FIG. 1B is a vertical cross-sectional view showing another configuration example of the photoelectric conversion unit.
  • FIG. 4 is a graph showing the spectral intensity distribution of a filter.
  • FIG. 1 is a conceptual diagram for explaining a compound parabolic concentrator. 1 is a diagram showing a light receiving range of a light receiving sensor and an irradiation range of light guided by a compound parabolic concentrator. FIG.
  • FIG. 1 is a block diagram showing the internal configuration of a tristimulus type photoelectric colorimeter, which is an optical measurement device in one embodiment of the present invention.
  • a tristimulus value photoelectric colorimeter 10 (hereinafter simply referred to as "colorimeter 10") in this embodiment is used, for example, in the inspection process of a liquid crystal panel manufacturing line, and measures the brightness and chromaticity of the display surface 12 of the liquid crystal panel.
  • colorimeter 10 a tristimulus value photoelectric colorimeter 10 in this embodiment is used, for example, in the inspection process of a liquid crystal panel manufacturing line, and measures the brightness and chromaticity of the display surface 12 of the liquid crystal panel.
  • the colorimeter 10 consists of a measurement probe section 14 and a measurement device main body section 16.
  • the measurement probe section 14 and the measurement device main body section 16 are constructed as a single unit.
  • the measurement probe unit 14 is placed facing the display surface 12 of the liquid crystal panel, which is the object to be measured, at a predetermined distance (for example, 3 cm).
  • the measurement probe unit 14 photoelectrically converts the light from the display surface of the liquid crystal panel into an electrical signal (analog signal) and inputs it to the measuring device main body unit 16.
  • the measurement probe section 14 is composed of a measurement optical system 27 and a light receiving system 28.
  • the measurement optical system 27 has an objective lens 21 and a beam splitting member 24.
  • the objective lens 21 is provided as an entrance portion for admitting light from the object to be measured.
  • the objective lens 21 is, for example, a plano-convex lens, and has a single positive power.
  • the beam splitting member 24 is provided as a light guiding portion for guiding the light incident by the objective lens 21. The beam splitting member 24 splits the beam that has passed through the objective lens 21 into three beams.
  • the light receiving system 28 has a photoelectric conversion section 25 and an amplifier section 26.
  • the photoelectric conversion section 25 receives the light guided by the beam splitter 24 and converts it into an electrical signal.
  • the photoelectric conversion section 25 has light receiving sensors 62p, 62q, and 62r that ultimately have the spectral sensitivity characteristics of a standard observer.
  • the light receiving sensors 62p, 62q, and 62r receive the three beams of light emitted from the beam splitter 24, photoelectrically convert them into electrical signals according to the incident intensity, and output them.
  • the amplifier section 26 has three amplifiers 26p, 26q, and 26r corresponding to the light receiving sensors 62p, 62q, and 62r, and amplifies the electrical signals (voltages) output from the light receiving sensors 62p, 62q, and 62r to a predetermined level.
  • Each amplifier 26p, 26q, 26r generates noise, and the magnitude of the noise decreases as the area of the light receiving sensors 62p, 62q, 62r becomes smaller. This point will be explained with reference to Figure 2.
  • Figure 2 is a graph showing the relationship between the capacitance of the input section of each amplifier 26p, 26q, 26r and the noise.
  • the horizontal axis is the capacitance [pF] of the input section of the amplifiers 26p, 26q, 26r, and the vertical axis is the magnitude of the noise.
  • the noise decreases as the capacitance of the input section decreases.
  • the capacitance of the input section decreases as the area of the light receiving sensors 62p, 62q, 62r decreases. Therefore, the magnitude of the noise of each amplifier 26p, 26q, 26r decreases as the light receiving area of the light receiving sensors 62p, 62q, 62r decreases.
  • the noise when the capacitance of the input section is about 230 pF, the noise is about 75. When the capacitance of the input section is about 23 pF, the noise is about 30, and the noise is reduced to 1/2.5. In other words, by reducing the area of the light receiving sensors 62p, 62q, 62r to 1/10, the S/N ratio can be increased by about three times.
  • amplifiers 26p, 26q, and 26r include an integrator circuit and a trans-impedance circuit (IV conversion circuit).
  • the measuring device main body 16 converts the electrical signal (analog signal) input from the measuring probe 14 into a digital signal and performs a specified calculation process. Through this calculation process, the measuring device main body 16 calculates tristimulus values (X, Y, Z), xyY (chromaticity coordinates, luminance) established by the CIE (International Commission on Illumination), T ⁇ uvY (correlated color temperature, color difference from the blackbody locus, luminance), and the like, and displays the calculation results on the display unit 33.
  • tristimulus values X, Y, Z
  • xyY chromaticity coordinates, luminance
  • T ⁇ uvY correlated color temperature, color difference from the blackbody locus, luminance
  • Figure 3 (A) is a diagram viewed from the front
  • Figure 3 (B) is a diagram of the photoelectric conversion unit 25 viewed from the light incident side.
  • the beam splitting member 24 is disposed on the optical axis L of the light incident on the objective lens 21 (hereinafter also simply referred to as the "optical axis of the objective lens 21").
  • the beam splitting member 24 has an optical fiber 55 that propagates light, and collimator lenses 56p, 56q, and 56r.
  • the optical fiber 55 is formed by bundling a number of optical fibers.
  • the bundled optical fibers are divided into three divisions 55p, 55q, and 55r at the middle of the length direction, and the optical fiber 55 has one light beam incident surface A and a total of three light beam exit surfaces B1, B2, and B3 at the tips of the divisions 55p, 55q, and 55r.
  • Each light beam exit surface B1, B2, and B3 is disposed at the apex of an equilateral triangle in the same vertical plane.
  • the optical fiber 55 is disposed so that the light beam incident surface A is located at a position away from the image side principal point PP of the objective lens 21 by the focal length f of the objective lens 21 (for convenience of explanation, in this embodiment, an example in which the image side principal point is approximately the same as the object side principal point is shown).
  • the objective lens 21 and the optical fiber 55 constitute a telecentric optical system.
  • an optical fiber 55 is used for the light beam splitting member 24.
  • this is not limited to the configuration, and other optical components that perform the same function as an optical fiber, such as an optical guide tube, may also be used.
  • the measurement probe 14 is set at a predetermined distance from the display surface 12 of the liquid crystal panel. Then, of the light beams emitted from each part of the measurement area AR of the liquid crystal panel, only the light beams having an emission angle of less than or equal to the maximum value ⁇ (hereinafter referred to as the maximum emission angle ⁇ ) with respect to the normal direction of the measurement area AR (in FIG. 3, the direction parallel to the optical axis L) enter the light beam incident surface A of the optical fiber 55.
  • the maximum emission angle ⁇ is determined by the focal length f of the objective lens 21 and the diameter R of the optical fiber 55 at the light beam incident surface A.
  • the incident light beam is split into three light beams by splitters 55p, 55q, and 55r within the optical fiber 55. Then, they are emitted from the light beam exit surfaces B1, B2, and B3, respectively.
  • Each optical fiber that makes up optical fiber 55 has a two-layer structure with a core located in the center and a cladding that surrounds the core.
  • the core is designed to have a higher refractive index than the cladding, so light propagates while being confined within the core by total internal reflection.
  • Optical fiber 55 is bent into a predetermined shape with light beam incident surface A and light beam exit surfaces B1, B2, and B3 fixed. Therefore, unless there are changes in state due to vibration, shock, temperature change, etc., the position of optical fiber 55 is maintained, and light incident on light beam incident surface A is emitted from light beam exit surfaces B1, B2, and B3 at a predetermined angle.
  • Collimator lenses 56p, 56q, and 56r are disposed in front of the light beam exit surfaces B1, B2, and B3 of the optical fibers 55, which are positioned at the vertices of an equilateral triangle.
  • the photoelectric conversion unit 25 is disposed in front of the collimator lenses 56p, 56q, and 56r.
  • the photoelectric conversion unit 25 includes, in order from the collimator lenses 56p, 56q, 56r side, three spectral sensitivity correction filters 61p, 61q, 61r, three compound parabolic concentrators (hereinafter also referred to as CPCs) 63p, 63q, 63r, and three light receiving sensors 62p, 62q, 62r.
  • CPCs compound parabolic concentrators
  • the light beams from the collimator lenses 56p, 56q, and 56r are incident on each of the spectral sensitivity correction filters 61p, 61q, and 61r.
  • the light beams emitted from the light beam emission surfaces B1, B2, and B3 of the optical fiber 55 are refracted by each of the collimator lenses 56p, 56q, and 56r so that the angle of incidence of the light beams on each of the spectral sensitivity correction filters 61p, 61q, and 61r is as perpendicular as possible. This is because each of the spectral sensitivity correction filters 61p, 61q, and 61r has an interference film as shown below, and is therefore incident angle dependent.
  • the spectral sensitivity correction filters 61p, 61q, and 61r are intended to provide the light receiving sensors 62p, 62q, and 62r with the spectral sensitivity of the standard observer as specified by the CIE.
  • the spectral sensitivity correction filters 61p, 61q, and 61r are interference filters that utilize the interference phenomenon of a thin-film interference film.
  • each of the spectral sensitivity correction filters 61p, 61q, and 61r is formed by coating the light beam incident surface of a transparent parallel plate 611 made of glass or the like with an interference film 612. By forming the interference film 612 on the light beam incident surface of the parallel plate 611, the filters 61p, 61q, and 61r can be easily created and maintained.
  • Spectral sensitivity correction filters 61p, 61q, and 61r each transmit only light in a predetermined wavelength range.
  • spectral sensitivity correction filter 61p has filter characteristics that are sensitive to the R (red) wavelength range. This filter characteristic corrects the light sensitivity of light receiving sensor 62p to the light sensitivity of a color matching function (X bar lambda) that has high sensitivity to the red wavelength range.
  • Spectral sensitivity correction filter 61q has filter characteristics that are sensitive to the G (green) wavelength range. This filter characteristic corrects the light sensitivity of light receiving sensor 62q to the light sensitivity of a color matching function (W bar lambda) that has high sensitivity to the green wavelength range.
  • Spectral sensitivity correction filter 61r has filter characteristics that are sensitive to the B (blue) wavelength range. This filter characteristic corrects the light sensitivity of light receiving sensor 62r to the light sensitivity of a color matching function (Z bar lambda) that has high sensitivity to the blue wavelength range.
  • the spectral sensitivity correction filters 61p, 61q, and 61r are adjusted so that the light sensitivity finally obtained by the colorimeter 10 approximates the desired color matching function (defined by CIE) as shown by ⁇ in Figure 5.
  • This adjustment is performed taking into account the transmittance of the spectral sensitivity correction filters 61p, 61q, and 61r, as well as the transmittance of the optical system (lenses 56p, 56q, and 56r and optical fiber 55, etc.), the light sensitivity of the light receiving sensors 62p, 62q, and 62r, the reflection characteristics at the light receiving sensor surfaces, etc.
  • the interference film 612 can be adjusted so that the final light receiving sensitivity is close to the desired color matching function even without the collimator lenses 56p, 56q, and 56r, the collimator lenses 56p, 56q, and 56r may be eliminated.
  • the CPCs 63p, 63q, and 63r arranged between the spectral sensitivity correction filters 61p, 61q, and 61r and the light receiving sensors 62p, 62q, and 62r are each made of a transparent material such as glass, and have a circular cross section perpendicular to the optical axis.
  • the CPCs 63p, 63q, and 63r are light collectors in which the internal reflection surface around the optical axis L is a parabolic surface, and both surfaces in the optical axis direction are flat surfaces perpendicular to the optical axis L.
  • the CPC 63p is shown as a representative, but the other CPCs 63q and 63r are the same.
  • the thick line connecting a 0 b and ab 0 is the outline (reflection surface) of the cross-sectional shape of the CPC 63p when cut along the optical axis L.
  • each of the spectral sensitivity correction filters 61p, 61q, and 61r enter the entrance surface 631 of each of the CPCs 63p, 63q, and 63r, are totally reflected by the parabolic surfaces of the CPCs 63p, 63q, and 63r, and are emitted from the exit surface 632.
  • the angle of incidence on the spectral sensitivity correction filters 61p, 61q, and 61r must be as vertical as possible. For this reason, the light must be collected on the light receiving sensors 62p, 62q, and 62r after passing through the filters 61p, 61q, and 61r.
  • the areas of the light beam exit surfaces B1, B2, and B3 of the optical fiber 55 are all set to be larger than the area of the incident surface 631 of each of the CPCs 63p, 63q, and 63r, in other words, the area of the light incident on each of the light receiving sensors 62p, 62q, and 62r. This allows a sufficient amount of light to be incident from the optical fiber 55 to the CPCs 63p, 63q, and 63r and further to the light receiving sensors 62p, 62q, and 62r.
  • the spectral sensitivity correction filters 61p, 61q, and 61r are configured by applying an interference film 612 to the light beam incident surface of the parallel plate 611.
  • the filters may be configured by applying an interference film 612 to the surface of the incident surface 631 of each CPC 63p, 63q, and 63r.
  • the distance between the optical fiber 55 and collimator lenses 56p, 56q, and 56r arranged on the incident side of the CPCs 63p, 63q, and 63r and the CPCs 63p, 63q, and 63r can be reduced.
  • the light receiving sensors 62p, 62q, 62r are, for example, silicon photocells (SPCs) with approximately the same light receiving sensitivity.
  • the light receiving sensors 62p, 62q, 62r are located on the optical axes of the CPCs 63p, 63q, 63r, respectively, at positions where the irradiation range of the light collected by the CPCs 63p, 63q, 63r is the light receiving range of the light receiving sensors 62p, 62q, 62r.
  • the light receiving sensors 62p, 62q, 62r each output a light receiving signal corresponding to a tristimulus value (X, Y, Z).
  • the exit surface 632 of the CPC 63p, 63q, 63r is a plane perpendicular to the optical axis. As shown in Figures 4(A) and (B), this exit surface 632 is bonded between the light receiving sensors 62p, 62q, 62r and the light receiving sensors 62p, 62q, 63r with an optical path bonding adhesive 64 having a refractive index almost the same as that of the CPC 63p, 63q, 63r. Therefore, the light beams collected by the CPC 63p, 63q, 63r reach the light receiving sensors 62p, 62q, 62r without being reflected on the surfaces of the light receiving sensors 62p, 62q, 62r.
  • the CPC 63p, 63q, 63r and the light receiving sensors 62p, 62q, 62r can be positioned and fixed with the optical path bonding adhesive 64, and the positional relationship between the two can be prevented from fluctuating.
  • the optical path bonding adhesive 64 is a UV curing adhesive
  • the CPC 63p, 63q, 63r can be UV cured while being guided to an accurate position. This allows the CPCs 63p, 63q, and 63r to be accurately positioned and fixed relative to the light receiving sensors 62p, 62q, and 62r.
  • the light receiving sensors 62p, 62q, and 62r are mounted on a sensor board 65.
  • the sensor board 65 is fixed to a holder 66, which guides the CPCs 63p, 63q, and 63r to accurate positions relative to the light receiving sensors 62p, 62q, and 62r.
  • the light transmitted through the spectral sensitivity correction filters 61p, 61q, and 61r is focused on the light receiving sensors 62p, 62q, and 62r by the CPCs 63p, 63q, and 63r. Therefore, the light beams emitted from the light beam emission surfaces B1, B2, and B3 of the optical fiber 55 are focused on the light receiving sensors 62p, 62q, and 62r. As shown representatively in FIG.
  • the circular irradiation range LA of the light beam (equal to the area of the emission surface 632 of the CPC 63p) can be made to approximately match the rectangular area (light receiving range) SA of the light receiving sensors 62p, 62q, and 62r. Therefore, even if the area of the light receiving sensors 62p, 62q, and 62r is small, the light can be efficiently focused on the light receiving sensors 62p, 62q, and 62r.
  • the capacity of the input section of the amplifiers 26p, 26q, and 26r that amplify the output of the light receiving sensors 62p, 62q, and 62r can be reduced. This allows the noise (N) of the amplifiers 26p, 26q, and 26r to be reduced, improving the S/N ratio of the measurement optical device 10.
  • the configuration does not use a condenser lens system to collect light as in the conventional configuration, there is no need to increase the number of lenses in the condenser lens system, and the configuration is simple.
  • the condenser lens system has a lower light collecting ability than the CPCs 63p, 63q, and 63r, and can only collect light to an area approximately equal to the exit area of the optical fiber 55, so it is difficult to make all the light beams reach the light receiving sensors 62p, 62q, and 62r.
  • this embodiment by collecting light using the CPCs 63p, 63q, and 63r, it is possible to efficiently collect light even with a small sensor area.
  • an air layer is required between the exit surface of the condenser lens and the light receiving sensors 62p, 62q, and 62r for refraction, and it is not possible to fill the space between the CPCs 63p, 63q, and 63r and the light receiving sensors 62p, 62q, and 62r with the optical path coupling adhesive 64 as in this embodiment. For this reason, it is not possible to accurately position and fix the condenser lens to the light receiving sensors 62p, 62q, and 62r. In contrast, in this embodiment, the gap between the CPCs 63p, 63q, and 63r and the light receiving sensors 62p, 62q, and 62r is filled with optical path coupling adhesive 64. This allows the CPCs 63p, 63q, and 63r to be accurately positioned and fixed relative to the light receiving sensors 62p, 62q, and 62r.
  • the light beam emitted from the optical fiber 55 is focused on the light receiving range of the light receiving sensors 62p, 62q, 62r via the CPCs 63p, 63q, 63r.
  • one-third of the light beam incident on the optical fiber 55 (all light beams emitted from each part of the measurement area AR of the liquid crystal panel at an angle equal to or smaller than the maximum emission angle ⁇ with respect to the normal direction of the measurement area AR) is incident on the light receiving sensors 62p, 62q, 62r, respectively. Therefore, the amount of light received by the light receiving sensors 62p, 62q, 62r does not decrease.
  • the measuring device main body 16 has an A/D conversion unit 31, a data memory 32, a display unit 33, an operation unit 35, a control unit 36, a power supply unit 37, and a communication unit 38.
  • the A/D converter 31 converts the received light signal input from the measurement probe 14 into a digital signal (measurement data).
  • the data memory 32 stores the measurement data output from the A/D converter 31.
  • the control unit 36 controls the measurement operation by centrally controlling the operation of the measurement probe 14 and the operation of each unit in the measuring device main body 16.
  • the control unit 36 uses the measurement data stored in the data memory 32 to calculate tristimulus values (X, Y, Z), xyY (chromaticity coordinates, luminance) established by the CIE, T ⁇ uvY (correlated color temperature, color difference from the blackbody locus, luminance), etc.
  • the display unit 33 displays the results of calculations performed by the control unit 36.
  • Various information related to the measurement is input to the operation unit 35.
  • the power supply unit 37 transforms the voltage of the power supplied from an external AC adapter (not shown) and supplies power to each component via the control unit 36.
  • the communication unit 38 outputs the results of calculations performed by the control unit 36 to the outside.
  • the present invention can be used as an optical measurement device capable of measuring the brightness, chromaticity, etc. of a measurement object such as a display.

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  • Spectroscopy & Molecular Physics (AREA)
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  • Spectrometry And Color Measurement (AREA)

Abstract

An optical device (10) for measurement comprises objective optics (21) and a plurality of kinds of photoelectric conversion units (25) that each only receive light of a predetermined wavelength region of light from the objective optics (21). Each of the photoelectric conversion units (25) includes: filters (61p), (61q), (61r) that transmit only light of the predetermined wavelength region using an interference film (612); light receiving sensors (62p), (62q), (62r) that receive the light transmitted through the filters and of which outputs are amplified by amplifiers (26p), (26q), (26r); and compound parabolic concentrators (63p), (63q), (63r) that are located between the filters (61p), (61q), (61r) and the light receiving sensors (62p), (62q), (62r), and that focus the light transmitted through the filters (61p), (61q), (61r) onto the light receiving sensors (62p), (62q), (62r).

Description

測定用光学装置Measuring Optical Device
　この発明は、例えばディスプレイ等の測定対象物の輝度や色度等を計測可能な測定用光学装置に関する。 This invention relates to an optical measurement device capable of measuring the luminance, chromaticity, etc. of a measurement object such as a display.
　例えば、OLED（Organic Light Emitting Diode）やマイクロLEDなど、より低輝度の描画が可能なディスプレイパネルが増加している。このため、このようなディスプレイパネル等の輝度、色度を計測する計測器には、より低輝度まで測定できることが求められている。 For example, there is an increase in display panels that can display images at lower brightness, such as OLEDs (Organic Light Emitting Diodes) and micro LEDs. For this reason, there is a demand for measuring instruments that measure the brightness and chromaticity of such display panels to be able to measure even lower brightnesses.
　計測器を、より低輝度まで測定できるようにするには、S/N比を向上する必要がある。S/N比においてS（信号）を増加させる為には受光センサに入射する光量を増加させる必要があるが、パネルの計測条件(測定径、開口角)の制約から難しい。よって、N（ノイズ） を減少させることで、S/N比を向上させることが提案されている。 In order to enable measuring instruments to measure lower luminance levels, it is necessary to improve the S/N ratio. To increase the S (signal) in the S/N ratio, it is necessary to increase the amount of light incident on the light receiving sensor, but this is difficult due to the constraints of the panel's measurement conditions (measurement diameter, aperture angle). Therefore, it has been proposed to improve the S/N ratio by reducing N (noise).
　受光センサの出力は増幅器で増幅されるが、増幅器のノイズ（N）は、アナログ・フロント・エンド（AFE）を使用する場合は特に、入力部の容量（＝センサ容量＋寄生容量）に依存する。入力部の容量は受光センサの面積に比例するので、センサ面積を小さくすることが有効であるが、センサ面積を小さくする為には、小さい面積に光を集める必要がある。 The output of the light receiving sensor is amplified by an amplifier, but the noise (N) of the amplifier depends on the capacitance of the input section (= sensor capacitance + parasitic capacitance), especially when an analog front end (AFE) is used. Since the capacitance of the input section is proportional to the area of the light receiving sensor, it is effective to reduce the sensor area, but in order to reduce the sensor area, it is necessary to concentrate light in a small area.
　特許文献１には、集光レンズ系を用いて受光センサに光を集める技術が提案されている。 Patent document 1 proposes a technology that uses a focusing lens system to focus light on a light receiving sensor.
特許第５５６５４５８号公報Patent No. 5565458
　しかしながら、特許文献１に記載のように、集光レンズ系を用いて小さいセンサ面積に光を集めようとすると、レンズ枚数が増加して構成が複雑になる一方で、効果は限定的であるという課題がある。 However, as described in Patent Document 1, when attempting to focus light on a small sensor area using a focusing lens system, the number of lenses increases, making the configuration more complex, while the effect is limited.
　この発明はこのような課題を解決するためになされたものであって、受光センサに効率よく集光してS/N比を向上させることができる測定用光学装置の提供を目的とする。 This invention was made to solve these problems, and aims to provide an optical measurement device that can efficiently focus light on a light receiving sensor to improve the S/N ratio.
　上記目的は、以下の手段によって達成される。
（１）対物光学系と、
　前記対物光学系からの光の内、各々所定の波長域の光のみを受光する複数種類の光電変換部と、
　を備えた測定用光学装置において、
　前記光電変換部のそれぞれは、
　干渉膜により所定の波長域の光のみを透過するフィルタと、
　前記フィルタを透過した光を受光するとともに、出力が増幅器により増幅される受光センサと、
　前記フィルタと受光センサの間に位置し、フィルタを透過した光を受光センサに集光する複合放物面集光器と、
　を備えている測定用光学装置。
（２）前記複合放物面集光器は透明材料で形成されている前項１に記載の測定用光学装置。
（３）前記複合放物面集光器の前記受光センサに対向する面は平面であり、前記複合放物面集光器と前記受光センサは光路結合用接着剤によって結合されている前項１または２に記載の測定用光学装置。
（４）前記フィルタは、平行平板の入射面に干渉膜が施されることにより形成されている前項１または２に記載の測定用光学装置。
（５）前記フィルタは、複合放物面集光器の入射面に干渉膜が施されることにより形成されている前項１または２に記載の測定用光学装置。
（６）前記対物光学系からの光を分割して各光電変換部に導く光ファイバーを有し、分割された光ファイバーの射出面の面積は、前記受光センサに入射する光の面積よりも大きい前項１または２に記載の測定用光学装置。 The above object can be achieved by the following means.
(1) an objective optical system;
a plurality of types of photoelectric conversion units each receiving only light of a predetermined wavelength range from the light from the objective optical system;
In a measuring optical device comprising:
Each of the photoelectric conversion units is
a filter that transmits only light of a predetermined wavelength range using an interference film;
a light receiving sensor that receives light transmitted through the filter and whose output is amplified by an amplifier;
a compound parabolic concentrator positioned between the filter and the light receiving sensor, for concentrating the light transmitted through the filter onto the light receiving sensor;
An optical measuring device comprising:
(2) The measurement optical device according to the preceding paragraph 1, wherein the compound parabolic concentrator is formed of a transparent material.
(3) An optical measurement device as described in the preceding paragraph 1 or 2, in which the surface of the compound parabolic concentrator facing the light receiving sensor is flat, and the compound parabolic concentrator and the light receiving sensor are joined by an optical path joining adhesive.
(4) The measuring optical device according to the above item 1 or 2, wherein the filter is formed by applying an interference film to the incident surface of a parallel plate.
(5) The measurement optical device according to the above item 1 or 2, wherein the filter is formed by applying an interference film to the incident surface of a compound parabolic concentrator.
(6) A measurement optical device described in the preceding paragraph 1 or 2, which has an optical fiber that splits the light from the objective optical system and guides it to each photoelectric conversion unit, and the area of the exit surface of the split optical fiber is larger than the area of the light incident on the light receiving sensor.
　前項（１）に記載の発明によれば、対物光学系と、対物光学系からの光の内、各々所定の波長域の光のみを受光する複数種類の光電変換部と、を備えた測定用光学装置において、光電変換部のそれぞれは、干渉膜により所定の波長域の光のみを透過するフィルタと、フィルタを透過した光を受光する。また、出力が増幅器により増幅される受光センサと、フィルタと受光センサの間に位置し、フィルタを透過した光を受光センサに集光する複合放物面集光器と、を備えている。つまり、フィルタを透過した光は複合放物面集光器により受光センサに集光されるから、センサ面積が小さくても効率よく集光させることができる。また、センサ面積を小さくできることで、受光センサの出力を増幅する増幅器の入力部の容量を小さくでき、増幅器のノイズ（Ｎ）を減少させることができるから、測定用光学装置のS/N比を向上することができる。 According to the invention described in the preceding paragraph (1), in a measurement optical device having an objective optical system and a plurality of types of photoelectric conversion units each of which receives only light of a predetermined wavelength range from the light from the objective optical system, each of the photoelectric conversion units has a filter that transmits only light of a predetermined wavelength range by an interference film, and receives the light transmitted through the filter. Also, the device has a light receiving sensor whose output is amplified by an amplifier, and a compound parabolic concentrator located between the filter and the light receiving sensor and which focuses the light transmitted through the filter on the light receiving sensor. In other words, since the light transmitted through the filter is focused on the light receiving sensor by the compound parabolic concentrator, it is possible to efficiently focus the light even if the sensor area is small. Furthermore, by making the sensor area smaller, it is possible to reduce the capacity of the input section of the amplifier that amplifies the output of the light receiving sensor, and the noise (N) of the amplifier can be reduced, thereby improving the S/N ratio of the measurement optical device.
　しかも、集光レンズ系を用いて集光する構成ではないから、集光レンズ系のレンズ枚数を増加させる必要はなく、構成も簡素になる。 Moreover, since the light is not focused using a focusing lens system, there is no need to increase the number of lenses in the focusing lens system, and the configuration is simple.
　前項（２）に記載の発明によれば、複合放物面集光器は透明材料で形成されるから、複合放物面集光器の集光特性が妨げられることはない。 According to the invention described in the preceding paragraph (2), the compound parabolic concentrator is formed from a transparent material, so the light-collecting properties of the compound parabolic concentrator are not impeded.
　前項（３）に記載の発明によれば、複合放物面集光器の受光センサに対向する面は平面であり、複合放物面集光器と受光センサは光路結合用接着剤によって結合される。従って、複合放物面集光器から出射された光束を、受光センサ表面で反射することなく受光センサに到達させることができる。また、複合放物面集光器と受光センサを位置決め固定することができ、両者の位置関係の変動を防止できる。 According to the invention described in the preceding paragraph (3), the surface of the compound parabolic concentrator facing the light receiving sensor is flat, and the compound parabolic concentrator and the light receiving sensor are joined by an optical path joining adhesive. Therefore, the light beam emitted from the compound parabolic concentrator can reach the light receiving sensor without being reflected on the surface of the light receiving sensor. In addition, the compound parabolic concentrator and the light receiving sensor can be positioned and fixed, preventing fluctuations in the positional relationship between them.
　前項（４）に記載の発明によれば、フィルタは平行平板の入射面に干渉膜が施されることにより形成されているから、フィルタの作成保持を容易に行うことができる。 According to the invention described in the previous paragraph (4), the filter is formed by applying an interference film to the incident surface of a parallel plate, making it easy to create and maintain the filter.
　前項（５）に記載の発明によれば、フィルタは、複合放物面集光器の入射面に干渉膜が施されることにより形成されている。このため、複合放物面集光器の入射側に配置される光学系素子と複合放物面集光器との距離を縮めることができる。 According to the invention described in the preceding paragraph (5), the filter is formed by applying an interference film to the incident surface of the compound parabolic concentrator. This makes it possible to reduce the distance between the optical system element arranged on the incident side of the compound parabolic concentrator and the compound parabolic concentrator.
　前項（６）に記載の発明によれば、対物光学系からの光を光ファイバーによって分割し、各光電変換部に導くことができる。また、分割された光ファイバーの射出面の面積は、受光センサに入射する光の面積よりも大きいから、十分な量の光を受光センサに入射させることができる。 According to the invention described in the preceding paragraph (6), the light from the objective optical system can be split by optical fibers and guided to each photoelectric conversion unit. In addition, since the area of the exit surface of the split optical fibers is larger than the area of the light incident on the light receiving sensor, a sufficient amount of light can be incident on the light receiving sensor.
この発明の一実施形態における測定用光学装置である三刺激値型光電色彩計の内部構成を示すブロック図である。1 is a block diagram showing the internal configuration of a tristimulus value photoelectric colorimeter, which is an optical measuring device according to an embodiment of the present invention. FIG. 各増幅器の入力部の容量とノイズとの関係を示すグラフである。11 is a graph showing the relationship between the capacitance of the input section of each amplifier and noise. 光電変換部と、光電変換部に導光する光束分割部材を含む光学系の各構成を説明するための図で、（Ａ）は正面から見た時の図、（Ｂ）は光電変換部を光入射側から見た時の図である。FIG. 1 is a diagram for explaining each component of an optical system including a photoelectric conversion unit and a beam splitting member that guides light to the photoelectric conversion unit, where (A) is a diagram viewed from the front, and (B) is a diagram of the photoelectric conversion unit viewed from the light incident side. （Ａ）は光電変換部の主要構成部材の縦断面図、（Ｂ）は光電変換部の他の構成例を示す縦断面図である。1A is a vertical cross-sectional view of the main components of a photoelectric conversion unit, and FIG. 1B is a vertical cross-sectional view showing another configuration example of the photoelectric conversion unit. フィルタの分光強度分布を示すグラフである。4 is a graph showing the spectral intensity distribution of a filter. 複合放物面集光器を説明するための概念図である。FIG. 1 is a conceptual diagram for explaining a compound parabolic concentrator. 受光センサの受光範囲と複合放物面集光器で導光される光の照射範囲を示す図である。1 is a diagram showing a light receiving range of a light receiving sensor and an irradiation range of light guided by a compound parabolic concentrator. FIG.
　以下、この発明の実施の形態について、図面を参照して説明する。 The following describes an embodiment of the present invention with reference to the drawings.
　図１は、この発明の一実施形態における測定用光学装置である三刺激値型光電色彩計の内部構成を示すブロック図である。 FIG. 1 is a block diagram showing the internal configuration of a tristimulus type photoelectric colorimeter, which is an optical measurement device in one embodiment of the present invention.
　図１において、本実施形態における三刺激値型光電色彩計１０（以下、単に、「色彩計１０」ともいう）は、たとえば、液晶パネルの製造ラインの検査工程で用いられ、液晶パネルの表示面１２の明るさと色度とを測定する。まず、色彩計１０の全体構成について説明する。 In FIG. 1, a tristimulus value photoelectric colorimeter 10 (hereinafter simply referred to as "colorimeter 10") in this embodiment is used, for example, in the inspection process of a liquid crystal panel manufacturing line, and measures the brightness and chromaticity of the display surface 12 of the liquid crystal panel. First, the overall configuration of the colorimeter 10 will be described.
　色彩計１０は、測定プローブ部１４と、測定器本体部１６とからなる。測定プローブ部１４および測定器本体部１６は、一体に構成されている。 The colorimeter 10 consists of a measurement probe section 14 and a measurement device main body section 16. The measurement probe section 14 and the measurement device main body section 16 are constructed as a single unit.
　測定プローブ部１４は、たとえば、被測定物である液晶パネルの表示面１２から所定の距離（一例として、３ｃｍ）だけ離して対向配置される。測定プローブ部１４は、液晶パネルの表示面からの光を電気信号（アナログ信号）に光電変換して測定器本体部１６に入力する。 The measurement probe unit 14 is placed facing the display surface 12 of the liquid crystal panel, which is the object to be measured, at a predetermined distance (for example, 3 cm). The measurement probe unit 14 photoelectrically converts the light from the display surface of the liquid crystal panel into an electrical signal (analog signal) and inputs it to the measuring device main body unit 16.
　　測定プローブ部１４は、測定光学系２７および受光系２８から構成されている。 The measurement probe section 14 is composed of a measurement optical system 27 and a light receiving system 28.
　測定光学系２７は、対物レンズ２１および光束分割部材２４を有する。対物レンズ２１は、被測定物からの光を入射させる入射部として設けられている。対物レンズ２１は、たとえば、平凸レンズからなり、単一の正のパワーを有する。光束分割部材２４は、対物レンズ２１により入射された光を導光する導光部として設けられている。光束分割部材２４は、対物レンズ２１を透過した光束を３つの光束に分割する。 The measurement optical system 27 has an objective lens 21 and a beam splitting member 24. The objective lens 21 is provided as an entrance portion for admitting light from the object to be measured. The objective lens 21 is, for example, a plano-convex lens, and has a single positive power. The beam splitting member 24 is provided as a light guiding portion for guiding the light incident by the objective lens 21. The beam splitting member 24 splits the beam that has passed through the objective lens 21 into three beams.
　受光系２８は、光電変換部２５および増幅部２６を有する。光電変換部２５は、光束分割部材２４が導光する光を受光し、電気信号に変換する。光電変換部２５は、図３で詳述するように、結果的に標準観測者の分光感度特性を持たせられる受光センサ６２ｐ，６２ｑ，６２ｒを有する。受光センサ６２ｐ，６２ｑ，６２ｒは、光束分割部材２４から出射される３つの光束をそれぞれ受光し、入射強度に応じた電気信号に光電変換して出力する。増幅部２６は、各受光センサ６２ｐ，６２ｑ，６２ｒに対応する３つの増幅器２６ｐ，２６ｑ，２６ｒを有し、各受光センサ６２ｐ，６２ｑ，６２ｒから出力される電気信号（電圧）をそれぞれ所定のレベルに増幅する。 The light receiving system 28 has a photoelectric conversion section 25 and an amplifier section 26. The photoelectric conversion section 25 receives the light guided by the beam splitter 24 and converts it into an electrical signal. As described in detail in FIG. 3, the photoelectric conversion section 25 has light receiving sensors 62p, 62q, and 62r that ultimately have the spectral sensitivity characteristics of a standard observer. The light receiving sensors 62p, 62q, and 62r receive the three beams of light emitted from the beam splitter 24, photoelectrically convert them into electrical signals according to the incident intensity, and output them. The amplifier section 26 has three amplifiers 26p, 26q, and 26r corresponding to the light receiving sensors 62p, 62q, and 62r, and amplifies the electrical signals (voltages) output from the light receiving sensors 62p, 62q, and 62r to a predetermined level.
　各増幅器２６ｐ，２６ｑ，２６ｒはノイズを発生し、ノイズの大きさは受光センサ６２ｐ，６２ｑ，６２ｒの面積が小さくなるほど減少する。この点を図２を参照して説明する。 Each amplifier 26p, 26q, 26r generates noise, and the magnitude of the noise decreases as the area of the light receiving sensors 62p, 62q, 62r becomes smaller. This point will be explained with reference to Figure 2.
　図２は各増幅器２６ｐ，２６ｑ，２６ｒの入力部の容量とノイズとの関係を示すグラフである。横軸は増幅器２６ｐ，２６ｑ，２６ｒの入力部の容量［ｐＦ］、縦軸はノイズの大きさである。同図に示すように、入力部の容量が小さくなるとノイズも減少する。入力部の容量は、受光センサ６２ｐ，６２ｑ，６２ｒの面積が小さくなると減少する。このため、各増幅器２６ｐ，２６ｑ，２６ｒのノイズの大きさは受光センサ６２ｐ，６２ｑ，６２ｒの受光面積が小さくなるほど減少する。例えば入力部の容量が約２３０ｐＦのときのノイズは約７５である。入力部の容量が約２３ｐＦのときのノイズは約３０であり、ノイズは１／２．５に減少する。つまり、受光センサ６２ｐ，６２ｑ，６２ｒの面積を１／１０にすることで、S/N比を約３倍にすることができる。 Figure 2 is a graph showing the relationship between the capacitance of the input section of each amplifier 26p, 26q, 26r and the noise. The horizontal axis is the capacitance [pF] of the input section of the amplifiers 26p, 26q, 26r, and the vertical axis is the magnitude of the noise. As shown in the figure, the noise decreases as the capacitance of the input section decreases. The capacitance of the input section decreases as the area of the light receiving sensors 62p, 62q, 62r decreases. Therefore, the magnitude of the noise of each amplifier 26p, 26q, 26r decreases as the light receiving area of the light receiving sensors 62p, 62q, 62r decreases. For example, when the capacitance of the input section is about 230 pF, the noise is about 75. When the capacitance of the input section is about 23 pF, the noise is about 30, and the noise is reduced to 1/2.5. In other words, by reducing the area of the light receiving sensors 62p, 62q, 62r to 1/10, the S/N ratio can be increased by about three times.
　なお、本実施形態では、増幅器２６ｐ，２６ｑ，２６ｒには積分回路やトランス・インピーダンス回路（ＩＶ変換回路）が含まれる。 In this embodiment, amplifiers 26p, 26q, and 26r include an integrator circuit and a trans-impedance circuit (IV conversion circuit).
　測定器本体部１６は、測定プローブ部１４から入力された電気信号（アナログ信号）をデジタル信号に変換して、所定の演算処理を行なう。測定器本体部１６は、その演算処理により、三刺激値（Ｘ，Ｙ，Ｚ）、ＣＩＥ（国際照明委員会）で制定されているｘｙＹ（色度座標、輝度）、ＴΔｕｖＹ（相関色温度、黒体軌跡からの色差、輝度）などを算出し、その演算結果を表示部３３に表示する。 The measuring device main body 16 converts the electrical signal (analog signal) input from the measuring probe 14 into a digital signal and performs a specified calculation process. Through this calculation process, the measuring device main body 16 calculates tristimulus values (X, Y, Z), xyY (chromaticity coordinates, luminance) established by the CIE (International Commission on Illumination), TΔuvY (correlated color temperature, color difference from the blackbody locus, luminance), and the like, and displays the calculation results on the display unit 33.
　図３を参照して、光電変換部２５と、光電変換部２５に導光する光束分割部材２４を含む光学系の各構成を詳述する。同図（Ａ）は正面から見た時の図であり、同図（Ｂ）は光電変換部２５を光入射側から見た時の図である。 Referring to Figure 3, the components of the optical system including the photoelectric conversion unit 25 and the light beam splitter member 24 that guides light to the photoelectric conversion unit 25 will be described in detail. Figure 3 (A) is a diagram viewed from the front, and Figure 3 (B) is a diagram of the photoelectric conversion unit 25 viewed from the light incident side.
　光束分割部材２４は、対物レンズ２１により入射された光の光軸Ｌ（以下、単に「対物レンズ２１の光軸」ともいう）上に配置されている。光束分割部材２４は、光を伝播させる光ファイバー５５と、コリメータレンズ５６ｐ，５６ｑ，５６ｒとを有する。 The beam splitting member 24 is disposed on the optical axis L of the light incident on the objective lens 21 (hereinafter also simply referred to as the "optical axis of the objective lens 21"). The beam splitting member 24 has an optical fiber 55 that propagates light, and collimator lenses 56p, 56q, and 56r.
　光ファイバー５５は、複数本の光ファイバーが束ねられて構成されている。光ファイバー５５は、束ねられた複数本の光ファイバーが長さ方向の中間部分で３つの分割部５５ｐ，５５ｑ，５５ｒに分割されることにより、１つの光束入射面Ａと、各分割部５５ｐ，５５ｑ，５５ｒの先端の合計３つの光束出射面Ｂ１，Ｂ２，Ｂ３とを有する。各光束出射面Ｂ１，Ｂ２，Ｂ３は、同一の垂直平面内において正三角形の頂点の位置にそれぞれ配置されている。光ファイバー５５は、光束入射面Ａが対物レンズ２１の像側主点ＰＰ（なお、説明の便宜上、本実施の形態では像側主点が物体側主点と略一致しているものを例示する）から対物レンズ２１の焦点距離ｆだけ離れた位置となるように配置されている。すなわち、対物レンズ２１および光ファイバー５５によって、テレセントリック光学系が構成されている。 The optical fiber 55 is formed by bundling a number of optical fibers. The bundled optical fibers are divided into three divisions 55p, 55q, and 55r at the middle of the length direction, and the optical fiber 55 has one light beam incident surface A and a total of three light beam exit surfaces B1, B2, and B3 at the tips of the divisions 55p, 55q, and 55r. Each light beam exit surface B1, B2, and B3 is disposed at the apex of an equilateral triangle in the same vertical plane. The optical fiber 55 is disposed so that the light beam incident surface A is located at a position away from the image side principal point PP of the objective lens 21 by the focal length f of the objective lens 21 (for convenience of explanation, in this embodiment, an example in which the image side principal point is approximately the same as the object side principal point is shown). In other words, the objective lens 21 and the optical fiber 55 constitute a telecentric optical system.
　本実施の形態では、光束分割部材２４に光ファイバー５５を用いている。しかし、このような構成に限られず、たとえば、光導管等のように光ファイバーと同等の機能を果たす他の光学部品を用いてもよい。 In this embodiment, an optical fiber 55 is used for the light beam splitting member 24. However, this is not limited to the configuration, and other optical components that perform the same function as an optical fiber, such as an optical guide tube, may also be used.
　測定プローブ部１４を液晶パネルの表示面１２から所定の間隔だけ離してセットする。すると、液晶パネルの被測定領域ＡＲの各部から出射される光束のうち、被測定領域ＡＲの法線方向（図３中では、光軸Ｌに平行な方向）に対する出射角の最大値α（以下、最大出射角αという）以下の光束だけが、光ファイバー５５の光束入射面Ａに入射する。なお、最大出射角αは、対物レンズ２１の焦点距離ｆと、光ファイバー５５の光束入射面Ａにおける直径Ｒとによって決定される。入射した光束は、光ファイバー５５内で分割部５５ｐ，５５ｑ，５５ｒにより３つの光束に分割される。そして、それぞれ、光束出射面Ｂ１，Ｂ２，Ｂ３から出射される。 The measurement probe 14 is set at a predetermined distance from the display surface 12 of the liquid crystal panel. Then, of the light beams emitted from each part of the measurement area AR of the liquid crystal panel, only the light beams having an emission angle of less than or equal to the maximum value α (hereinafter referred to as the maximum emission angle α) with respect to the normal direction of the measurement area AR (in FIG. 3, the direction parallel to the optical axis L) enter the light beam incident surface A of the optical fiber 55. The maximum emission angle α is determined by the focal length f of the objective lens 21 and the diameter R of the optical fiber 55 at the light beam incident surface A. The incident light beam is split into three light beams by splitters 55p, 55q, and 55r within the optical fiber 55. Then, they are emitted from the light beam exit surfaces B1, B2, and B3, respectively.
　光ファイバー５５を構成する各光ファイバーは、中心部に配置されるコアと、コアの周囲を覆うクラッドとの二層構造を有する。コアは、クラッドと比較して屈折率が高く設計されているため、光は、全反射によりコア内に閉じこめられた状態で伝搬する。 Each optical fiber that makes up optical fiber 55 has a two-layer structure with a core located in the center and a cladding that surrounds the core. The core is designed to have a higher refractive index than the cladding, so light propagates while being confined within the core by total internal reflection.
　光ファイバー５５は、光束入射面Ａと、光束射出面Ｂ１，Ｂ２，Ｂ３とが固定された状態において、所定の形状に曲げられた姿勢で設けられている。このため、振動衝撃や温度変化等の状態変化がなければ、光ファイバー５５の姿勢は維持されており、光束入射面Ａに入射した光は、光束射出面Ｂ１，Ｂ２，Ｂ３より所定の角度で出射する。 Optical fiber 55 is bent into a predetermined shape with light beam incident surface A and light beam exit surfaces B1, B2, and B3 fixed. Therefore, unless there are changes in state due to vibration, shock, temperature change, etc., the position of optical fiber 55 is maintained, and light incident on light beam incident surface A is emitted from light beam exit surfaces B1, B2, and B3 at a predetermined angle.
　正三角形の頂点の位置に配置された光ファイバー５５の各光束射出面Ｂ１，Ｂ２，Ｂ３の前方には、それぞれコリメータレンズ５６ｐ，５６ｑ，５６ｒが配置されている。コリメータレンズ５６ｐ，５６ｑ，５６ｒの前方に光電変換部２５が配置されている。 Collimator lenses 56p, 56q, and 56r are disposed in front of the light beam exit surfaces B1, B2, and B3 of the optical fibers 55, which are positioned at the vertices of an equilateral triangle. The photoelectric conversion unit 25 is disposed in front of the collimator lenses 56p, 56q, and 56r.
　光電変換部２５はコリメータレンズ５６ｐ，５６ｑ，５６ｒ側から順に、３個の分光感度補正フィルタ６１ｐ，６１ｑ，６１ｒと、３個の複合放物面集光器（以下、CPCともいう）６３ｐ，６３ｑ，６３ｒと、３個の受光センサ６２ｐ，６２ｑ，６２ｒを備えている。 The photoelectric conversion unit 25 includes, in order from the collimator lenses 56p, 56q, 56r side, three spectral sensitivity correction filters 61p, 61q, 61r, three compound parabolic concentrators (hereinafter also referred to as CPCs) 63p, 63q, 63r, and three light receiving sensors 62p, 62q, 62r.
　各分光感度補正フィルタ６１ｐ，６１ｑ，６１ｒには、各コリメータレンズ５６ｐ，５６ｑ，５６ｒからの光束が入射される。光ファイバー５５の光束射出面Ｂ１，Ｂ２，Ｂ３から出射された光束の各分光感度補正フィルタ６１ｐ，６１ｑ，６１ｒへの入射角度ができるだけ垂直になるように、各コリメータレンズ５６ｐ，５６ｑ，５６ｒによって屈折される。各分光感度補正フィルタ６１ｐ，６１ｑ，６１ｒは以下のように干渉膜を有しているので、入射角依存性があるからである。 The light beams from the collimator lenses 56p, 56q, and 56r are incident on each of the spectral sensitivity correction filters 61p, 61q, and 61r. The light beams emitted from the light beam emission surfaces B1, B2, and B3 of the optical fiber 55 are refracted by each of the collimator lenses 56p, 56q, and 56r so that the angle of incidence of the light beams on each of the spectral sensitivity correction filters 61p, 61q, and 61r is as perpendicular as possible. This is because each of the spectral sensitivity correction filters 61p, 61q, and 61r has an interference film as shown below, and is therefore incident angle dependent.
　分光感度補正フィルタ６１ｐ，６１ｑ，６１ｒは、受光センサ６２ｐ，６２ｑ，６２ｒにＣＩＥ規定の標準観測者の分光感度を持たせるためのものである。この実施形態では、各分光感度補正フィルタ６１ｐ，６１ｑ，６１ｒは、薄膜の干渉膜の干渉現象を利用した干渉フィルタである。各分光感度補正フィルタ６１ｐ，６１ｑ，６１ｒは、図４（Ａ）に拡大断面図で示すように、ガラス等からなる透明な平行平板６１１の光束入射側の面に干渉膜６１２が被覆形成されることにより構成されている。平行平板６１１の光束入射側の面に干渉膜６１２を形成することで、フィルタ６１ｐ，６１ｑ，６１ｒの作成保持を容易に行うことができる。 The spectral sensitivity correction filters 61p, 61q, and 61r are intended to provide the light receiving sensors 62p, 62q, and 62r with the spectral sensitivity of the standard observer as specified by the CIE. In this embodiment, the spectral sensitivity correction filters 61p, 61q, and 61r are interference filters that utilize the interference phenomenon of a thin-film interference film. As shown in the enlarged cross-sectional view of FIG. 4A, each of the spectral sensitivity correction filters 61p, 61q, and 61r is formed by coating the light beam incident surface of a transparent parallel plate 611 made of glass or the like with an interference film 612. By forming the interference film 612 on the light beam incident surface of the parallel plate 611, the filters 61p, 61q, and 61r can be easily created and maintained.
　分光感度補正フィルタ６１ｐ，６１ｑ，６１ｒは、それぞれ所定の波長域の光のみを透過する。具体的には、分光感度補正フィルタ６１ｐは、Ｒ（赤）の波長領域に感度を有するフィルタ特性を有する。このフィルタ特性によって受光センサ６２ｐの受光感度は、赤の波長域に大きな感度を有する等色関数（エックス・バー・ラムダ）の受光感度に補正されている。分光感度補正フィルタ６１ｑは、Ｇ（緑）の波長領域に感度を有するフィルタ特性を有する。このフィルタ特性によって受光センサ６２ｑの受光感度は、緑の波長域に大きな感度を有する等色関数（ワイ・バー・ラムダ）の受光感度に補正されている。分光感度補正フィルタ６１ｒは、Ｂ（青）の波長領域に感度を有するフィルタ特性を有する。このフィルタ特性によって受光センサ６２ｒの受光感度は、青の波長域に大きな感度を有する等色関数（ゼット・バー・ラムダ）の受光感度に補正されている。 Spectral sensitivity correction filters 61p, 61q, and 61r each transmit only light in a predetermined wavelength range. Specifically, spectral sensitivity correction filter 61p has filter characteristics that are sensitive to the R (red) wavelength range. This filter characteristic corrects the light sensitivity of light receiving sensor 62p to the light sensitivity of a color matching function (X bar lambda) that has high sensitivity to the red wavelength range. Spectral sensitivity correction filter 61q has filter characteristics that are sensitive to the G (green) wavelength range. This filter characteristic corrects the light sensitivity of light receiving sensor 62q to the light sensitivity of a color matching function (W bar lambda) that has high sensitivity to the green wavelength range. Spectral sensitivity correction filter 61r has filter characteristics that are sensitive to the B (blue) wavelength range. This filter characteristic corrects the light sensitivity of light receiving sensor 62r to the light sensitivity of a color matching function (Z bar lambda) that has high sensitivity to the blue wavelength range.
　また、最終的に色彩計１０で得られる受光感度が、図５にβで示すような所望の（ＣＩＥで規定される）等色関数に近似したものとなるように、各分光感度補正フィルタ６１ｐ，６１ｑ，６１ｒが調製されている。この調整は、分光感度補正フィルタ６１ｐ，６１ｑ，６１ｒの透過率に加え、光学系（レンズ５６ｐ，５６ｑ，５６ｒや、光ファイバー５５等）の透過率、受光センサ６２ｐ，６２ｑ，６２ｒの受光感度、受光センサ面等での反射特性などの特性を加味して行われる。 Furthermore, the spectral sensitivity correction filters 61p, 61q, and 61r are adjusted so that the light sensitivity finally obtained by the colorimeter 10 approximates the desired color matching function (defined by CIE) as shown by β in Figure 5. This adjustment is performed taking into account the transmittance of the spectral sensitivity correction filters 61p, 61q, and 61r, as well as the transmittance of the optical system ( lenses 56p, 56q, and 56r and optical fiber 55, etc.), the light sensitivity of the light receiving sensors 62p, 62q, and 62r, the reflection characteristics at the light receiving sensor surfaces, etc.
　なお、コリメータレンズ５６ｐ，５６ｑ，５６ｒがなくても、最終的に得られる受光感度が所望の等色関数に近似したものとなるように干渉膜６１２を調製することができれば、コリメータレンズ５６ｐ，５６ｑ，５６ｒを廃止してもよい。 In addition, if the interference film 612 can be adjusted so that the final light receiving sensitivity is close to the desired color matching function even without the collimator lenses 56p, 56q, and 56r, the collimator lenses 56p, 56q, and 56r may be eliminated.
　各分光感度補正フィルタ６１ｐ，６１ｑ，６１ｒと各受光センサ６２ｐ，６２ｑ，６２ｒとの間に配置されたCPC６３ｐ，６３ｑ，６３ｒは、それぞれガラス等の透明材料からなり、光軸と垂直な断面が円形である。 The CPCs 63p, 63q, and 63r arranged between the spectral sensitivity correction filters 61p, 61q, and 61r and the light receiving sensors 62p, 62q, and 62r are each made of a transparent material such as glass, and have a circular cross section perpendicular to the optical axis.
　CPC６３ｐ，６３ｑ，６３ｒは図６の概念図に示すように、光軸Ｌの周囲の内部反射面が放物面に、光軸方向の両面が光軸Ｌに垂直な平面に形成された集光器である。図６ではCPC６３ｐを代表として示しているが、他のCPC６３ｑ，６３ｒについても同じである。同図において、ａ０ｂおよびａｂ０を結ぶ太線部が光軸Ｌに沿って切断したときのCPC６３ｐの断面形状の輪郭（反射面）である。入射面６３１に垂直な光軸Ｌに対し許容半角θｍａｘ／２以内の角度で入射してきた光は、放物線の一部であるａ０ｂ（放物線Ａ０、対称軸ＡＡ’、焦点ａ）またはｂ０ａ（放物線Ｂ０、対称軸ＢＢ’、焦点ｂ）の鏡面により、放物線の特徴から高々一回の反射で射出面６３２に集光される。従って、左右両面を考えると、許容角θｍａｘ内の角度で入射面６３１から入射してくる光は全て射出面６３２に集光することができる。 As shown in the conceptual diagram of FIG. 6, the CPCs 63p, 63q, and 63r are light collectors in which the internal reflection surface around the optical axis L is a parabolic surface, and both surfaces in the optical axis direction are flat surfaces perpendicular to the optical axis L. In FIG. 6, the CPC 63p is shown as a representative, but the other CPCs 63q and 63r are the same. In the figure, the thick line connecting a 0 b and ab 0 is the outline (reflection surface) of the cross-sectional shape of the CPC 63p when cut along the optical axis L. Light incident at an angle within the allowable half angle θ max /2 with respect to the optical axis L perpendicular to the entrance surface 631 is collected on the exit surface 632 with at most one reflection due to the characteristics of the parabola by the mirror surface of a 0 b (parabola A 0 , symmetry axis AA', focus a) or b 0 a (parabola B 0 , symmetry axis BB', focus b), which is a part of the parabola. Therefore, considering both the left and right surfaces, all of the light incident from the entrance surface 631 at angles within the allowable angle θ max can be collected on the exit surface 632 .
　このように、各分光感度補正フィルタ６１ｐ，６１ｑ，６１ｒを通過した光束はCPC６３ｐ，６３ｑ，６３ｒの各入射面６３１に入射し、CPC６３ｐ，６３ｑ，６３ｒの放物面で全反射して射出面６３２から射出される。なお、分光感度補正フィルタ６１ｐ，６１ｑ，６１ｒへの入射角度はできるだけ垂直になるようにする必要がある。このため、受光センサ６２ｐ，６２ｑ，６２ｒへの集光はフィルタ６１ｐ，６１ｑ，６１ｒを透過した後に行う必要がある。 In this way, the light beams that pass through each of the spectral sensitivity correction filters 61p, 61q, and 61r enter the entrance surface 631 of each of the CPCs 63p, 63q, and 63r, are totally reflected by the parabolic surfaces of the CPCs 63p, 63q, and 63r, and are emitted from the exit surface 632. Note that the angle of incidence on the spectral sensitivity correction filters 61p, 61q, and 61r must be as vertical as possible. For this reason, the light must be collected on the light receiving sensors 62p, 62q, and 62r after passing through the filters 61p, 61q, and 61r.
　また、この実施形態では、光ファイバー５５の光束射出面Ｂ１，Ｂ２，Ｂ３の面積は、いずれも、各CPC６３ｐ，６３ｑ，６３ｒの入射面６３１の面積、換言すれば各受光センサ６２ｐ，６２ｑ，６２ｒに入射する光の面積よりも大きく設定されている。これにより、十分な量の光を光ファイバー５５からCPC６３ｐ，６３ｑ，６３ｒへさらに受光センサ６２ｐ，６２ｑ，６２ｒへと入射させることができる。 In addition, in this embodiment, the areas of the light beam exit surfaces B1, B2, and B3 of the optical fiber 55 are all set to be larger than the area of the incident surface 631 of each of the CPCs 63p, 63q, and 63r, in other words, the area of the light incident on each of the light receiving sensors 62p, 62q, and 62r. This allows a sufficient amount of light to be incident from the optical fiber 55 to the CPCs 63p, 63q, and 63r and further to the light receiving sensors 62p, 62q, and 62r.
　前述したように、分光感度補正フィルタ６１ｐ，６１ｑ，６１ｒが、平行平板６１１の光束入射側の面に干渉膜６１２が施されることにより構成されている例を示した。しかし、図４（Ｂ）に示すように、各CPC６３ｐ，６３ｑ，６３ｒの入射面６３１の表面に干渉膜６１２が施されることにより構成されてよい。CPC６３ｐ，６３ｑ，６３ｒの入射面６３１に干渉膜６１２が施されていることで、CPC６３ｐ，６３ｑ，６３ｒの入射側に配置される光ファイバー５５やコリメータレンズ５６ｐ，５６ｑ，５６ｒとCPC６３ｐ，６３ｑ，６３ｒとの距離を縮めることができる。 As described above, an example has been shown in which the spectral sensitivity correction filters 61p, 61q, and 61r are configured by applying an interference film 612 to the light beam incident surface of the parallel plate 611. However, as shown in FIG. 4B, the filters may be configured by applying an interference film 612 to the surface of the incident surface 631 of each CPC 63p, 63q, and 63r. By applying the interference film 612 to the incident surface 631 of the CPCs 63p, 63q, and 63r, the distance between the optical fiber 55 and collimator lenses 56p, 56q, and 56r arranged on the incident side of the CPCs 63p, 63q, and 63r and the CPCs 63p, 63q, and 63r can be reduced.
　受光センサ６２ｐ，６２ｑ，６２ｒは、略同一の受光感度を有する、たとえば、ＳＰＣ（シリコンフォトセル）からなる。受光センサ６２ｐ，６２ｑ，６２ｒは、それぞれ、CPC６３ｐ，６３ｑ，６３ｒの光軸上であって、CPC６３ｐ，６３ｑ，６３ｒによって集光される光の照射範囲が受光センサ６２ｐ，６２ｑ，６２ｒの受光範囲となる位置に配置されている。受光センサ６２ｐ，６２ｑ，６２ｒからは、それぞれ三刺激値（Ｘ，Ｙ，Ｚ）に相当する受光信号が出力される。 The light receiving sensors 62p, 62q, 62r are, for example, silicon photocells (SPCs) with approximately the same light receiving sensitivity. The light receiving sensors 62p, 62q, 62r are located on the optical axes of the CPCs 63p, 63q, 63r, respectively, at positions where the irradiation range of the light collected by the CPCs 63p, 63q, 63r is the light receiving range of the light receiving sensors 62p, 62q, 62r. The light receiving sensors 62p, 62q, 62r each output a light receiving signal corresponding to a tristimulus value (X, Y, Z).
　さらに、この実施形態では、CPC６３ｐ，６３ｑ，６３ｒの射出面６３２は光軸に垂直な平面である。図４（Ａ）（Ｂ）に示すように、この射出面６３２は受光センサ６２ｐ，６２ｑ，６２ｒとの間で屈折率がCPC６３ｐ，６３ｑ，６３ｒとほぼ同じ光路接合用接着剤６４で接合されている。このため、CPC６３ｐ，６３ｑ，６３ｒで集光された光束は受光センサ６２ｐ，６２ｑ，６２ｒの表面で反射されることなく受光センサ６２ｐ，６２ｑ，６２ｒに到達する。また、CPC６３ｐ，６３ｑ，６３ｒと受光センサ６２ｐ，６２ｑ，６２ｒを光路接合用接着剤６４で位置決め固定することができ、両者の位置関係の変動を防止できる。また、光路接合用接着剤６４はUV硬化接着剤なので、CPC６３ｐ，６３ｑ，６３ｒが正確な位置にガイドされた状態でUV硬化させることができる。これにより、受光センサ６２ｐ，６２ｑ，６２ｒに対してCPC６３ｐ，６３ｑ，６３ｒを正確に位置決め固定することができる。 Furthermore, in this embodiment, the exit surface 632 of the CPC 63p, 63q, 63r is a plane perpendicular to the optical axis. As shown in Figures 4(A) and (B), this exit surface 632 is bonded between the light receiving sensors 62p, 62q, 62r and the light receiving sensors 62p, 62q, 63r with an optical path bonding adhesive 64 having a refractive index almost the same as that of the CPC 63p, 63q, 63r. Therefore, the light beams collected by the CPC 63p, 63q, 63r reach the light receiving sensors 62p, 62q, 62r without being reflected on the surfaces of the light receiving sensors 62p, 62q, 62r. In addition, the CPC 63p, 63q, 63r and the light receiving sensors 62p, 62q, 62r can be positioned and fixed with the optical path bonding adhesive 64, and the positional relationship between the two can be prevented from fluctuating. In addition, since the optical path bonding adhesive 64 is a UV curing adhesive, the CPC 63p, 63q, 63r can be UV cured while being guided to an accurate position. This allows the CPCs 63p, 63q, and 63r to be accurately positioned and fixed relative to the light receiving sensors 62p, 62q, and 62r.
　図３に示すように、各受光センサ６２ｐ，６２ｑ，６２ｒはセンサ基板６５に搭載されている。センサ基板６５はホルダー６６に固定され、ホルダー６６はCPC６３ｐ，６３ｑ，６３ｒを受光センサ６２ｐ，６２ｑ，６２ｒに対して正確な位置にガイドする。 As shown in FIG. 3, the light receiving sensors 62p, 62q, and 62r are mounted on a sensor board 65. The sensor board 65 is fixed to a holder 66, which guides the CPCs 63p, 63q, and 63r to accurate positions relative to the light receiving sensors 62p, 62q, and 62r.
　このように、この実施形態では、分光感度補正フィルタ６１ｐ，６１ｑ，６１ｒを透過した光はCPC６３ｐ，６３ｑ，６３ｒによって受光センサ６２ｐ，６２ｑ，６２ｒに集光される。従って、光ファイバー５５の各光束出射面Ｂ１，Ｂ２，Ｂ３から出射される光束は各受光センサ６２ｐ，６２ｑ，６２ｒに集光される。図７にCPC６３ｐ及び受光センサ６２ｐについて代表して示すように、当該光束の円形の照射範囲ＬＡ（CPC６３ｐの射出面６３２の面積に等しい）を受光センサ６２ｐ，６２ｑ，６２ｒの矩形の面積（受光範囲）ＳＡに略一致させることができる。このため、受光センサ６２ｐ，６２ｑ，６２ｒの面積が小さくても効率よく受光センサ６２ｐ，６２ｑ，６２ｒに集光させることができる。また、受光センサ６２ｐ，６２ｑ，６２ｒの面積を小さくできることで、受光センサ６２ｐ，６２ｑ，６２ｒの出力を増幅する増幅器２６ｐ，２６ｑ，２６ｒの入力部の容量を小さくできる。そのため、増幅器２６ｐ，２６ｑ，２６ｒのノイズ（Ｎ）を減少させることができるから、測定用光学装置１０のS/N比を向上することができる。 In this embodiment, the light transmitted through the spectral sensitivity correction filters 61p, 61q, and 61r is focused on the light receiving sensors 62p, 62q, and 62r by the CPCs 63p, 63q, and 63r. Therefore, the light beams emitted from the light beam emission surfaces B1, B2, and B3 of the optical fiber 55 are focused on the light receiving sensors 62p, 62q, and 62r. As shown representatively in FIG. 7 for the CPC 63p and the light receiving sensor 62p, the circular irradiation range LA of the light beam (equal to the area of the emission surface 632 of the CPC 63p) can be made to approximately match the rectangular area (light receiving range) SA of the light receiving sensors 62p, 62q, and 62r. Therefore, even if the area of the light receiving sensors 62p, 62q, and 62r is small, the light can be efficiently focused on the light receiving sensors 62p, 62q, and 62r. In addition, by reducing the area of the light receiving sensors 62p, 62q, and 62r, the capacity of the input section of the amplifiers 26p, 26q, and 26r that amplify the output of the light receiving sensors 62p, 62q, and 62r can be reduced. This allows the noise (N) of the amplifiers 26p, 26q, and 26r to be reduced, improving the S/N ratio of the measurement optical device 10.
　しかも、従来のように集光レンズ系を用いて集光する構成ではないから、集光レンズ系のレンズ枚数を増加させる必要はなく、構成も簡素になる。なお、集光レンズ系では集光能力がCPC６３ｐ，６３ｑ，６３ｒよりも低く、光ファイバー５５の射出面積と同程度の面積にしか集光できない為に全ての光束を受光センサ６２ｐ，６２ｑ，６２ｒに到達させることは難しい。しかし、本実施形態ではCPC６３ｐ，６３ｑ，６３ｒを用いて集光することで、小さいセンサ面積でも効率よく集光することができる。また、集光レンズの射出面と受光センサ６２ｐ，６２ｑ，６２ｒの間には屈折の為に空気層が必要であり、本実施形態のようにCPC６３ｐ，６３ｑ，６３ｒと受光センサ６２ｐ，６２ｑ，６２ｒとの間を光路結合用接着剤６４で埋めることができない。このため、受光センサ６２ｐ，６２ｑ，６２ｒに対して集光レンズを正確に位置決め固定することもできない。これに対して本実施形態では、CPC６３ｐ，６３ｑ，６３ｒと受光センサ６２ｐ，６２ｑ，６２ｒとの間を光路結合用接着剤６４で埋めている。このため、受光センサ６２ｐ，６２ｑ，６２ｒに対してCPC６３ｐ，６３ｑ，６３ｒを正確に位置決め固定できる。 Moreover, since the configuration does not use a condenser lens system to collect light as in the conventional configuration, there is no need to increase the number of lenses in the condenser lens system, and the configuration is simple. Note that the condenser lens system has a lower light collecting ability than the CPCs 63p, 63q, and 63r, and can only collect light to an area approximately equal to the exit area of the optical fiber 55, so it is difficult to make all the light beams reach the light receiving sensors 62p, 62q, and 62r. However, in this embodiment, by collecting light using the CPCs 63p, 63q, and 63r, it is possible to efficiently collect light even with a small sensor area. In addition, an air layer is required between the exit surface of the condenser lens and the light receiving sensors 62p, 62q, and 62r for refraction, and it is not possible to fill the space between the CPCs 63p, 63q, and 63r and the light receiving sensors 62p, 62q, and 62r with the optical path coupling adhesive 64 as in this embodiment. For this reason, it is not possible to accurately position and fix the condenser lens to the light receiving sensors 62p, 62q, and 62r. In contrast, in this embodiment, the gap between the CPCs 63p, 63q, and 63r and the light receiving sensors 62p, 62q, and 62r is filled with optical path coupling adhesive 64. This allows the CPCs 63p, 63q, and 63r to be accurately positioned and fixed relative to the light receiving sensors 62p, 62q, and 62r.
　なお、受光センサ６２ｐ，６２ｑ，６２ｒにワイヤボンディングを施す場合、図７に示す矩形の受光範囲ＳＡのうちの円形の照射範囲ＬＡを除く部分に施せば良い。 When applying wire bonding to the light receiving sensors 62p, 62q, and 62r, it is sufficient to apply it to the rectangular light receiving area SA shown in FIG. 7 excluding the circular irradiation area LA.
　こうして、光ファイバー５５から出射される光束をCPC６３ｐ，６３ｑ，６３ｒを介して受光センサ６２ｐ，６２ｑ，６２ｒの受光範囲に集光する。これにより、光ファイバー５５に入射された光束（液晶パネルの被測定領域ＡＲの各部から出射される当該被測定領域ＡＲの法線方向に対する最大出射角α以下の全ての光束）は１／３ずつそれぞれ受光センサ６２ｐ，６２ｑ，６２ｒに入射される。このため、受光センサ６２ｐ，６２ｑ，６２ｒでの受光光量が低下することはない。 In this way, the light beam emitted from the optical fiber 55 is focused on the light receiving range of the light receiving sensors 62p, 62q, 62r via the CPCs 63p, 63q, 63r. As a result, one-third of the light beam incident on the optical fiber 55 (all light beams emitted from each part of the measurement area AR of the liquid crystal panel at an angle equal to or smaller than the maximum emission angle α with respect to the normal direction of the measurement area AR) is incident on the light receiving sensors 62p, 62q, 62r, respectively. Therefore, the amount of light received by the light receiving sensors 62p, 62q, 62r does not decrease.
　次に、図１を参照して、測定器本体部１６の構成についてより具体的に説明する。測定器本体部１６は、Ａ／Ｄ変換部３１と、データメモリ３２と、表示部３３と、操作部３５と、制御部３６と、電源部３７と、通信部３８とを有する。 Next, the configuration of the measuring device main body 16 will be described in more detail with reference to FIG. 1. The measuring device main body 16 has an A/D conversion unit 31, a data memory 32, a display unit 33, an operation unit 35, a control unit 36, a power supply unit 37, and a communication unit 38.
　Ａ／Ｄ変換部３１は、測定プローブ部１４から入力される受光信号をデジタルの信号（測定データ）に変換する。データメモリ３２は、Ａ／Ｄ変換部３１から出力される測定データを記憶する。制御部３６は、測定プローブ部１４の動作や、測定器本体部１６内の各部の動作を集中的に制御することで測定動作を制御する。制御部３６は、データメモリ３２に格納された測定データを用いて、三刺激値（Ｘ，Ｙ，Ｚ）、ＣＩＥで制定されているｘｙＹ（色度座標、輝度）、ＴΔｕｖＹ（相関色温度、黒体軌跡からの色差、輝度）などを演算する。 The A/D converter 31 converts the received light signal input from the measurement probe 14 into a digital signal (measurement data). The data memory 32 stores the measurement data output from the A/D converter 31. The control unit 36 controls the measurement operation by centrally controlling the operation of the measurement probe 14 and the operation of each unit in the measuring device main body 16. The control unit 36 uses the measurement data stored in the data memory 32 to calculate tristimulus values (X, Y, Z), xyY (chromaticity coordinates, luminance) established by the CIE, TΔuvY (correlated color temperature, color difference from the blackbody locus, luminance), etc.
　表示部３３は、制御部３６における演算結果を表示する。操作部３５には、測定に関する各種情報（測定の指示、表示モードの設定、測定レンジ等）が入力される。電源部３７は、外部のＡＣアダプター（不図示）から供給される電力の電圧を変圧して制御部３６を介して各構成要素に電力を供給する。通信部３８は、制御部３６における演算結果を外部に出力する。 The display unit 33 displays the results of calculations performed by the control unit 36. Various information related to the measurement (measurement instructions, display mode settings, measurement range, etc.) is input to the operation unit 35. The power supply unit 37 transforms the voltage of the power supplied from an external AC adapter (not shown) and supplies power to each component via the control unit 36. The communication unit 38 outputs the results of calculations performed by the control unit 36 to the outside.
　本願は、２０２２年１０月２１日付で出願された日本国特許出願の特願２０２２－１６９４１７号の優先権主張を伴うものであり、その開示内容は、そのまま本願の一部を構成するものである。 This application claims priority from Japanese Patent Application No. 2022-169417, filed on October 21, 2022, the disclosures of which are incorporated herein by reference in their entirety.
　本発明は、例えばディスプレイ等の測定対象物の輝度や色度等を計測可能な測定用光学装置として利用可能である。 The present invention can be used as an optical measurement device capable of measuring the brightness, chromaticity, etc. of a measurement object such as a display.
　１０　三刺激値型光電色彩計
　１２　表示面
　１４　測定プローブ部
　１６　測定器本体部
　２１　対物レンズ
　２４　光束分割部材
　２５　光電変換部
　２６　増幅部
　２６ｐ，２６ｑ，２６ｒ　増幅器
　２７　測定光学系
　２８　受光系
　３１　Ａ／Ｄ変換部
　３２　データメモリ
　３３　表示部
　３５　操作部
　３６　制御部
　３７　電源部
　３８　通信部
　５５　光ファイバー
　５５ｐ，５５ｑ，５５ｒ　分割部
　５６ｐ，５６ｑ，５６ｒ　コリメータレンズ
　６１ｐ，６１ｑ，６１ｒ　分光感度補正フィルタ
　６２ｐ，６２ｑ，６２ｒ　受光センサ
　６３ｐ，６３ｑ，６３ｒ　複合放物面集光器
　６４　光路接合用接着剤
　６５　センサ基板
　６６　ホルダー
　６１１　平行平板
　６１２　干渉膜
　６３１　入射面
　６３２　射出面 REFERENCE SIGNS LIST 10 Tristimulus value photoelectric colorimeter 12 Display surface 14 Measurement probe section 16 Measuring device main body 21 Objective lens 24 Light beam splitting member 25 Photoelectric conversion section 26 Amplification section 26p, 26q, 26r Amplifier 27 Measurement optical system 28 Light receiving system 31 A/D conversion section 32 Data memory 33 Display section 35 Operation section 36 Control section 37 Power supply section 38 Communication section 55 Optical fiber 55p, 55q, 55r Splitting section 56p, 56q, 56r Collimator lens 61p, 61q, 61r Spectral sensitivity correction filter 62p, 62q, 62r Light receiving sensor 63p, 63q, 63r Compound parabolic concentrator 64 Optical path joining adhesive 65 Sensor substrate 66 Holder 611 Parallel plate 612 interference film 631 incident surface 632 exit surface

Claims (6)

  1. 　対物光学系と、
    　前記対物光学系からの光の内、各々所定の波長域の光のみを受光する複数種類の光電変換部と、
    　を備えた測定用光学装置において、
    　前記光電変換部のそれぞれは、
    　干渉膜により所定の波長域の光のみを透過するフィルタと、
    　前記フィルタを透過した光を受光するとともに、出力が増幅器により増幅される受光センサと、
    　前記フィルタと受光センサの間に位置し、フィルタを透過した光を受光センサに集光する複合放物面集光器と、
    　を備えている測定用光学装置。     An objective optical system;
    a plurality of types of photoelectric conversion units each receiving only light of a predetermined wavelength range from the light from the objective optical system;
    In a measuring optical device comprising:
    Each of the photoelectric conversion units is
    a filter that transmits only light of a predetermined wavelength range using an interference film;
    a light receiving sensor that receives light transmitted through the filter and whose output is amplified by an amplifier;
    a compound parabolic concentrator positioned between the filter and the light receiving sensor, for concentrating the light transmitted through the filter onto the light receiving sensor;
    An optical measuring device comprising:
  2. 　前記複合放物面集光器は透明材料で形成されている請求項１に記載の測定用光学装置。 The optical measurement device of claim 1, wherein the compound parabolic concentrator is formed of a transparent material.
  3. 　前記複合放物面集光器の前記受光センサに対向する面は平面であり、前記複合放物面集光器と前記受光センサは光路結合用接着剤によって結合されている請求項１または２に記載の測定用光学装置。 The optical measurement device according to claim 1 or 2, wherein the surface of the compound parabolic concentrator facing the light receiving sensor is flat, and the compound parabolic concentrator and the light receiving sensor are joined by an adhesive for optical path joining.
  4. 　前記フィルタは、平行平板の入射面に干渉膜が施されることにより形成されている請求項１または２に記載の測定用光学装置。 The optical measurement device according to claim 1 or 2, wherein the filter is formed by applying an interference film to the incident surface of a parallel plate.
  5. 　前記フィルタは、複合放物面集光器の入射面に干渉膜が施されることにより形成されている請求項１または２に記載の測定用光学装置。 The measurement optical device according to claim 1 or 2, wherein the filter is formed by applying an interference film to the incident surface of a compound parabolic concentrator.
  6. 　前記対物光学系からの光を分割して各光電変換部に導く光ファイバーを有し、分割された光ファイバーの射出面の面積は、前記受光センサに入射する光の面積よりも大きい請求項１または２に記載の測定用光学装置。
     
          3. The measurement optical device according to claim 1, further comprising an optical fiber that splits the light from the objective optical system and guides it to each photoelectric conversion unit, and the area of the exit surface of the split optical fiber is larger than the area of the light incident on the light receiving sensor.
PCT/JP2023/036817 2022-10-21 2023-10-11 Optical device for measurement WO2024085027A1 (en)

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US20140145069A1 (en) * 2012-11-28 2014-05-29 Intersil Americas LLC Packaged light detector semiconductor devices with non-imaging optics for ambient light and/or optical proxmity sensing, methods for manufacturing the same, and systems including the same
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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6037415B2 (en) * 1979-11-22 1985-08-26 松下電器産業株式会社 infrared detection device
WO2011142071A1 (en) * 2010-05-14 2011-11-17 コニカミノルタセンシング株式会社 Optical system for measurement, luminance meter using the optical system, color luminance meter, and color meter
US20140145069A1 (en) * 2012-11-28 2014-05-29 Intersil Americas LLC Packaged light detector semiconductor devices with non-imaging optics for ambient light and/or optical proxmity sensing, methods for manufacturing the same, and systems including the same
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