Measurement optical device

Abstract

An optical device (10) for measurement is provided with: an objective optical system (21); and a plurality of types of photoelectric conversion units (25) that respectively receive only light in a predetermined wavelength domain among the light from the objective optical system (21), each of the photoelectric conversion units (25) being provided with: filters (61p), (61q), (61r) that transmit only light in the predetermined wavelength domain by means of an interference film (612), and filters (61p), (61q), (61r) that transmit only light in the predetermined wavelength domain by means of the interference film (612); light-receiving sensors (62p), (62q), (62r) that receive the light transmitted through the filter, and that output the light-receiving sensors (62p), (62q), (62r) amplified by amplifiers (26p), (26q), (26r); and compound parabolic condensers (63p), (63q), (63r), which are positioned between the filters (61p), (61q), (61r) and the light receiving sensors (62p), (62q), (62r), and which condense the light transmitted through the filters (61p), (61q), (61r) to the light receiving sensors (62p), (62q), (62r).

Description

Technical Field

[0001] The present invention relates to an optical measuring device capable of measuring brightness, chromaticity, etc. of a measuring object such as a display, for example. Background Art

[0002] For example, there are more and more display panels that can display at lower brightness, such as OLED (Organic Light Emitting Diode) and micro LED. Therefore, it is required that measuring instruments for measuring brightness and chromaticity of such display panels can measure even lower brightness.

[0003] In order to enable the measuring instrument to measure lower brightness, the S / N ratio needs to be improved. In order to increase S (signal) in the S / N ratio, the amount of light incident on the light-receiving sensor needs to be increased, but this is difficult due to the constraints of the panel measurement conditions (measurement diameter, aperture angle). Therefore, it is recommended to improve the S / N ratio by reducing N (noise).

[0004] The output of the light-receiving sensor is amplified by the amplifier, but the noise (N) of the amplifier depends on the capacitance of the input section (= sensor capacitance + parasitic capacitance) when using an analog front end (AFE). The capacitance of the input section is proportional to the area of ​​the light-receiving sensor, so reducing the sensor area is effective, but in order to reduce the sensor area, it is necessary to concentrate the light into a small area.

[0005] Patent Document 1 proposes a technique for focusing light onto a light receiving sensor using a condenser lens system.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent No. 5565458 Summary of the invention

[0009] However, as described in Patent Document 1, when trying to focus light on a small sensor area using a condenser lens system, there is a problem that the number of lenses increases and the structure becomes complicated, while the effect is limited.

[0010] The present invention has been made to solve such a problem, and an object of the present invention is to provide an optical measuring device capable of efficiently focusing light on a light receiving sensor to improve the S / N ratio.

[0011] The above-mentioned object is achieved by the following means.

[0012] (1) An optical device for measurement, comprising:

[0013] an objective optical system; and

[0014] The plurality of types of photoelectric conversion units each receive only light in a predetermined wavelength range among the light from the objective optical system, wherein:

[0015] Each of the photoelectric conversion units comprises:

[0016] Filters use interference films to transmit only light in a predetermined wavelength range;

[0017] a light receiving sensor that receives light transmitted through the filter, and whose output is amplified by an amplifier; and

[0018] The compound parabolic concentrator is located between the filter and the light receiving sensor, and focuses the light transmitted through the filter to the light receiving sensor.

[0019] (2) In the optical measuring device according to the above Item 1, the compound parabolic concentrator is formed of a transparent material.

[0020] (3) In the measuring optical device according to the above item 1 or 2, a surface of the compound parabolic concentrator facing the light receiving sensor is a flat surface, and the compound parabolic concentrator and the light receiving sensor are bonded to each other by an adhesive for bonding an optical path.

[0021] (4) In the measuring optical device according to the above item 1 or 2, the filter is formed by applying an interference film on the incident surface of a parallel plate.

[0022] (5) In the measuring optical device according to the above item 1 or 2, the filter is formed by applying an interference film on the incident surface of a compound parabolic condenser.

[0023] (6) The measuring optical device according to item 1 or 2 above has an optical fiber for splitting the light from the objective optical system and guiding it to each photoelectric conversion unit, and the area of ​​the emission surface of the split optical fiber is larger than the area of ​​the light incident on the light receiving sensor.

[0024] According to the invention described in the preceding item (1), in an optical device for measurement that includes an objective optical system and a plurality of types of photoelectric conversion units that receive only light in a predetermined wavelength range among the light from the objective optical system, each photoelectric conversion unit includes: a filter that transmits only light in a predetermined wavelength range by using an interference film; a light receiving sensor that receives light transmitted through the filter and whose output is amplified by an amplifier; and a compound parabolic condenser that is located between the filter and the light receiving sensor and condenses the light transmitted through the filter to the light receiving sensor. That is, the light transmitted through the filter is condensed by the compound parabolic condenser to the light receiving sensor, so that light can be efficiently condensed even if the sensor area is small. In addition, since the sensor area can be reduced, the capacitance of the input unit of the amplifier that amplifies the output of the light receiving sensor can be reduced, and the noise (N) of the amplifier can be reduced, so that the S / N ratio of the optical device for measurement can be improved.

[0025] Furthermore, since the structure does not use a condensing lens system to condense light, there is no need to increase the number of lenses of the condensing lens system, and the structure becomes simple.

[0026] According to the invention described in the above item (2), the compound parabolic concentrator is formed of a transparent material, so the focusing characteristics of the compound parabolic concentrator are not hindered.

[0027] According to the invention described in the preceding item (3), the surface of the compound parabolic concentrator facing the light receiving sensor is a plane, and the compound parabolic concentrator and the light receiving sensor are bonded by an adhesive for bonding an optical path. 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, and the positional relationship between the two can be prevented from changing.

[0028] According to the invention described in the above item (4), the optical filter is formed by applying the interference film to the incident surface of the parallel plate, so the optical filter can be easily manufactured and maintained.

[0029] According to the invention described in the above item (5), the filter is formed by applying the interference film on the incident surface of the compound parabolic condenser. Therefore, the distance between the optical system element arranged on the incident side of the compound parabolic condenser and the compound parabolic condenser can be shortened.

[0030] According to the invention described in the preceding item (6), the light from the objective optical system can be divided by optical fiber and guided to each photoelectric conversion unit. In addition, the area of ​​the emission surface of the divided optical fiber is larger than the area of ​​the light incident on the light receiving sensor, so a sufficient amount of light can be incident on the light receiving sensor. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 11 is a block diagram showing the internal structure of a tristimulus value type photoelectric colorimeter as a measuring optical device in one embodiment of the present invention.

[0032] Figure 2 : is a graph showing the relationship between the capacitance and noise of the input section of each amplifier.

[0033] Figure 3 The drawings are used to illustrate the structures of an optical system including a photoelectric conversion unit and a beam splitting component that guides light to the photoelectric conversion unit. (A) is a diagram when the photoelectric conversion unit is observed from the front, and (B) is a diagram when the photoelectric conversion unit is observed from the light incident side.

[0034] Figure 4 (A) is a longitudinal sectional view of main components of the photoelectric conversion part, and (B) is a longitudinal sectional view showing another structural example of the photoelectric conversion part.

[0035] Figure 5 is a graph showing the spectral intensity distribution of the filter.

[0036] Figure 6 This is a conceptual diagram for explaining a compound parabolic concentrator.

[0037] Figure 7 It is a diagram showing the light receiving range of the light receiving sensor and the irradiation range of the light guided by the compound parabolic concentrator. DETAILED DESCRIPTION

[0038] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0039] Figure 1 1 is a block diagram showing the internal structure of a tristimulus value type photoelectric colorimeter as a measuring optical device in one embodiment of the present invention.

[0040] exist Figure 1 The tristimulus photoelectric colorimeter 10 (hereinafter also referred to as "colorimeter 10") in this embodiment is used, for example, in an inspection process of a liquid crystal panel production line to measure the brightness and chromaticity of a display surface 12 of the liquid crystal panel. First, the overall structure of the colorimeter 10 is described.

[0041] The colorimeter 10 includes a measurement probe unit 14 and a measurement device body 16. The measurement probe unit 14 and the measurement device body 16 are integrally configured.

[0042] The measuring probe 14 is disposed at a predetermined distance (3 cm as an example) from the display surface 12 of the liquid crystal panel to be measured. The measuring probe 14 photoelectrically converts 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 16.

[0043] The measuring probe unit 14 includes a measuring optical system 27 and a light receiving system 28 .

[0044] The measuring optical system 27 includes an objective lens 21 and a beam splitter 24. The objective lens 21 is provided as an incident portion into which light from the object to be measured is incident. The objective lens 21 is composed of, for example, a plano-convex lens and has a single positive optical power. The beam splitter 24 is provided as a light guide portion for guiding the light incident from the objective lens 21. The beam splitter 24 splits the light beam after passing through the objective lens 21 into three light beams.

[0045] The light receiving system 28 includes a photoelectric conversion unit 25 and an amplifier 26. The photoelectric conversion unit 25 receives the light guided by the beam splitter 24 and converts it into an electrical signal. Figure 3 As described in detail in FIG. 1 , the light receiving sensors 62p, 62q, and 62r have the spectral sensitivity characteristics of a standard observer. The light receiving sensors 62p, 62q, and 62r receive the three light beams emitted from the light beam splitting component 24, respectively, and photoelectrically convert them into electrical signals corresponding to the incident intensity and output them. The amplifier 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 predetermined levels.

[0046] Each amplifier 26p, 26q, 26r generates noise, and the smaller the area of ​​the light receiving sensors 62p, 62q, 62r, the smaller the noise. Figure 2 , explaining this point.

[0047] Figure 2 : is a graph showing the relationship between the capacitance and noise of the input section of each amplifier 26p, 26q, 26r. The horizontal axis is the capacitance [pF] of the input section of the amplifier 26p, 26q, 26r, and the vertical axis is the magnitude of the noise. As shown in the figure, if the capacitance of the input section becomes smaller, the noise also decreases. If the area of ​​the light-receiving sensors 62p, 62q, 62r becomes smaller, the capacitance of the input section decreases. Therefore, the smaller the light-receiving area of ​​the light-receiving sensors 62p, 62q, 62r, the smaller the magnitude of the noise of each amplifier 26p, 26q, 26r. For example, when the capacitance of the input section is about 230pF, the noise is about 75. When the capacitance of the input section is about 23pF, the noise is about 30, and the noise is reduced to 1 / 2.5. That is, by setting the area of ​​the light-receiving sensors 62p, 62q, 62r to 1 / 10, the S / N ratio can be made about 3 times.

[0048] In addition, in the present embodiment, the amplifiers 26p, 26q, and 26r include an integrating circuit and a transformer / impedance circuit (IV conversion circuit).

[0049] The measuring device main body 16 converts the electric signal (analog signal) input from the measuring probe 14 into a digital signal and performs a predetermined operation process. The measuring device main body 16 calculates the tristimulus values ​​(X, Y, Z), xyY (chromaticity coordinates, brightness) and TΔuvY (correlated color temperature, color difference from the black body locus, brightness) established by CIE (International Commission on Illumination) through the operation process, and displays the operation results on the display unit 33.

[0050] Reference Figure 3 , details are given of the structures of the optical system including the photoelectric conversion unit 25 and the beam splitting member 24 that guides light to the photoelectric conversion unit 25. The figure (A) is a figure when the photoelectric conversion unit 25 is observed from the front, and the figure (B) is a figure when the photoelectric conversion unit 25 is observed from the light incident side.

[0051] The beam splitter 24 is disposed on the optical axis L of the light incident on the objective lens 21 (hereinafter referred to as "optical axis of the objective lens 21"). The beam splitter 24 includes an optical fiber 55 for propagating light and collimating lenses 56p, 56q, and 56r.

[0052] The optical fiber 55 is formed by bundling a plurality of optical fibers. The bundled plurality of optical fibers are divided into three divisions 55p, 55q, and 55r in the middle portion in the length direction, so that the optical fiber 55 has a beam incident surface A and a total of three beam exit surfaces B1, B2, and B3 at the front ends of the divisions 55p, 55q, and 55r. Each beam exit surface B1, B2, and B3 is respectively arranged at the position of the vertex of an equilateral triangle in the same vertical plane. The optical fiber 55 is configured so that the beam incident surface A becomes a position away from the focal length f of the objective lens 21 from the image side principal point PP of the objective lens 21 (in addition, for ease of explanation, the image side principal point and the object side principal point are roughly consistent in this embodiment). That is, the telecentric optical system is formed by the objective lens 21 and the optical fiber 55.

[0053] In this embodiment, the optical fiber 55 is used as the light beam splitting member 24. However, the present invention is not limited to this structure, and other optical members that perform the same function as the optical fiber, such as a light guide, may be used.

[0054] The measuring probe section 14 is provided at a predetermined interval from the display surface 12 of the liquid crystal panel. Thus, among the light beams emitted from the respective portions of the measured region AR of the liquid crystal panel, only the light beams in the normal direction (in the direction of the vertical axis) of the measured region AR are emitted. Figure 3 A light beam having a maximum value α (hereinafter referred to as the maximum emission angle α) of the emission angle in a direction parallel to the optical axis L in the optical fiber 55 is incident on 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 in the light beam incident surface A of the optical fiber 55. The incident light beam is split into three light beams by the splitters 55p, 55q, and 55r in the optical fiber 55. Then, the light beams are emitted from the light beam emission surfaces B1, B2, and B3, respectively.

[0055] Each optical fiber constituting the optical fiber 55 has a two-layer structure of a core disposed at the center and a metal cladding covering the core. The refractive index of the core is designed to be higher than that of the metal cladding, so that light propagates in a state of being confined in the core by total reflection.

[0056] The optical fiber 55 is set in a posture bent into a predetermined shape with the beam incident surface A and the beam exit surfaces B1, B2, and B3 fixed. Therefore, if there is no state change such as vibration shock, temperature change, etc., the posture of the optical fiber 55 is maintained, and the light incident on the beam incident surface A is emitted from the beam exit surfaces B1, B2, and B3 at a predetermined angle.

[0057] Collimating lenses 56p, 56q, 56r are arranged in front of the light beam emitting surfaces B1, B2, B3 of the optical fiber 55 arranged at the vertices of the equilateral triangle, respectively. The photoelectric conversion unit 25 is arranged in front of the collimating lenses 56p, 56q, 56r.

[0058] The photoelectric conversion unit 25 includes three spectral sensitivity correction filters 61p, 61q, 61r, three compound parabolic concentrators (hereinafter also referred to as CPC) 63p, 63q, 63r, and three light receiving sensors 62p, 62q, 62r in sequence from the collimating lenses 56p, 56q, 56r.

[0059] The light beams from the collimating lenses 56p, 56q, and 56r are incident on the spectral sensitivity correction filters 61p, 61q, and 61r. The light beams emitted from the light beam exit surfaces B1, B2, and B3 of the optical fiber 55 are refracted by the collimating lenses 56p, 56q, and 56r so that the incident angles of the light beams emitted to the spectral sensitivity correction filters 61p, 61q, and 61r are as vertical as possible. This is because the spectral sensitivity correction filters 61p, 61q, and 61r have interference films as described below, so there is an incident angle dependency.

[0060] The spectral sensitivity correction filters 61p, 61q, and 61r are components for making the light receiving sensors 62p, 62q, and 62r have the spectral sensitivity of the standard observer specified by CIE. In this embodiment, each spectral sensitivity correction filter 61p, 61q, and 61r is an interference filter that uses the interference phenomenon of the interference film of the thin film. Figure 4 As shown in the enlarged cross-sectional view in (A), each spectral sensitivity correction filter 61p, 61q, 61r is formed by covering the light beam incident side surface of a transparent parallel plate 611 made of glass, etc. with an interference film 612. By forming the interference film 612 on the light beam incident side surface of the parallel plate 611, the filters 61p, 61q, 61r can be easily manufactured and maintained.

[0061] The spectral sensitivity correction filters 61p, 61q, and 61r transmit only light in a predetermined wavelength range. Specifically, the spectral sensitivity correction filter 61p has a filter characteristic that is sensitive in the R (red) wavelength range. By this filter characteristic, the light receiving sensitivity of the light receiving sensor 62p is corrected to an isochromatic function that has a large sensitivity in the red wavelength range. The spectral sensitivity correction filter 61q has a filter characteristic that has sensitivity in the wavelength region of G (green). Through this filter characteristic, the light receiving sensitivity of the light receiving sensor 62q is corrected to an isochromatic function that has a large sensitivity in the wavelength region of green. The spectral sensitivity correction filter 61r has a filter characteristic that has sensitivity in the B (blue) wavelength region. Through this filter characteristic, the light receiving sensitivity of the light receiving sensor 62r is corrected to an isochromatic function that has a large sensitivity in the blue wavelength region. Light sensitivity.

[0062] In addition, the light receiving sensitivity finally obtained by the color meter 10 is made to be the same as that in Figure 5 Each spectral sensitivity correction filter 61p, 61q, 61r is modulated in such a way as to approximate the desired (CIE-specified) color-matching function shown in β in the figure. This adjustment is performed by taking into account the transmittance of the spectral sensitivity correction filters 61p, 61q, 61r, the transmittance of the optical system (lenses 56p, 56q, 56r, optical fiber 55, etc.), the light receiving sensitivity of the light receiving sensors 62p, 62q, 62r, the reflection characteristics of the light receiving sensor surface, etc., in addition to the transmittance of the spectral sensitivity correction filters 61p, 61q, 61r.

[0063] Even without the collimator lenses 56p, 56q, and 56r, the collimator lenses 56p, 56q, and 56r may be removed as long as the interference film 612 can be modulated so that the finally obtained light receiving sensitivity approximates the desired isochromatic function.

[0064] CPCs 63p, 63q, 63r disposed between the spectral sensitivity correction filters 61p, 61q, 61r and the light receiving sensors 62p, 62q, 62r are respectively made of a transparent material such as glass and have a circular cross section perpendicular to the optical axis.

[0065] like Figure 6 As shown in the conceptual diagram of the CPC 63p, 63q, and 63r, the internal reflection surface around the optical axis L is formed as a parabola, and the two surfaces in the optical axis direction are formed as planes perpendicular to the optical axis L. Figure 6 In the figure, CPC63p is shown as a representative example, but the same is true for other CPC63q and 63r. 0 b and ab 0The thick line portion of is the outline (reflection surface) of the cross-sectional shape of CPC63p when cut along the optical axis L. The allowable half angle θ is θ relative to the optical axis L perpendicular to the incident surface 631. max Light incident at an angle of less than / 2 passes through a as part of the parabola 0 b(parabola A 0 , axis of symmetry AA', focus a) or b 0 a(parabola B 0 , symmetry axis BB', focus b), according to the characteristics of the parabola, the light is focused to the emission surface 632 with at most one reflection. Therefore, when considering the left and right surfaces, the allowable angle θ max At an angle within 630, all the light incident from the incident surface 631 can be focused onto the emitting surface 632.

[0066] In this way, the light beams that have passed through the spectral sensitivity correction filters 61p, 61q, and 61r are incident on the incident surfaces 631 of the CPCs 63p, 63q, and 63r, and are totally reflected by the paraboloids of the CPCs 63p, 63q, and 63r and emitted from the emission surface 632. In addition, the incident angles to the spectral sensitivity correction filters 61p, 61q, and 61r need to be as vertical as possible. Therefore, after passing through the filters 61p, 61q, and 61r, the light beams need to be focused on the light receiving sensors 62p, 62q, and 62r.

[0067] In addition, in this embodiment, the areas of the light beam exiting 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 CPC 63p, 63q, and 63r, in other words, the area of ​​the light incident on each light receiving sensor 62p, 62q, and 62r. ​​Thus, a sufficient amount of light can be incident from the optical fiber 55 to the CPC 63p, 63q, and 63r and further to the light receiving sensors 62p, 62q, and 62r.

[0068] As described above, the example of forming the spectral sensitivity correction filters 61p, 61q, and 61r by applying the interference film 612 to the surface of the parallel plate 611 on the light beam incident side is shown. Figure 4 As shown in FIG. 2B , an interference film 612 may be applied to the surface of the incident surface 631 of each CPC 63p, 63q, 63r. By applying the interference film 612 to the incident surface 631 of the CPC 63p, 63q, 63r, the distance between the optical fiber 55, the collimating lens 56p, 56q, 56r and the CPC 63p, 63q, 63r arranged on the incident side of the CPC 63p, 63q, 63r can be shortened.

[0069] The light receiving sensors 62p, 62q, and 62r are composed of, for example, SPCs (silicon photocells) having substantially the same light receiving sensitivity. The light receiving sensors 62p, 62q, and 62r are respectively arranged on the optical axes of the CPCs 63p, 63q, and 63r, and are located at positions where the irradiation range of the light focused by the CPCs 63p, 63q, and 63r becomes the light receiving range of the light receiving sensors 62p, 62q, and 62r. ​​The light receiving sensors 62p, 62q, and 62r respectively output light receiving signals corresponding to the tristimulus values ​​(X, Y, and Z).

[0070] Furthermore, in this embodiment, the emission surface 632 of CPC 63p, 63q, 63r is a plane perpendicular to the optical axis. Figure 4 As shown in (A) and (B), the emitting surface 632 and the light receiving sensors 62p, 62q, and 62r are bonded by an optical path bonding adhesive 64 having a refractive index substantially the same as that of the CPCs 63p, 63q, and 63r. Therefore, the light beam focused by the CPCs 63p, 63q, and 63r reaches the light receiving sensors 62p, 62q, and 62r without being reflected on the surface of the light receiving sensors 62p, 62q, and 62r. ​​In addition, the CPCs 63p, 63q, and 63r and the light receiving sensors 62p, 62q, and 62r can be positioned and fixed by the optical path bonding adhesive 64, and the positional relationship between the two can be prevented from changing. In addition, since the optical path bonding adhesive 64 is a UV curing adhesive, it can be UV cured in a state where the CPCs 63p, 63q, and 63r are guided to the correct position. This makes it possible to accurately position and fix the CPCs 63p, 63q, and 63r with respect to the light receiving sensors 62p, 62q, and 62r.

[0071] like Figure 3 As shown, each light receiving sensor 62p, 62q, 62r is mounted on a sensor substrate 65. The sensor substrate 65 is fixed to a holder 66, and the holder 66 guides the CPCs 63p, 63q, 63r to a correct position relative to the light receiving sensors 62p, 62q, 62r.

[0072] Thus, in this embodiment, the light transmitted through the spectral sensitivity correction filters 61p, 61q, 61r is focused by the CPCs 63p, 63q, 63r to the light receiving sensors 62p, 62q, 62r. ​​Therefore, the light beams emitted from the light beam emission surfaces B1, B2, B3 of the optical fiber 55 are focused to the light receiving sensors 62p, 62q, 62r. Figure 7As shown representatively in FIG. 6 , regarding CPC 63p and light receiving sensor 62p, the circular irradiation range LA (equal to the area of ​​the emission surface 632 of CPC 63p) of the light beam can be made substantially consistent with the rectangular area (light receiving range) SA of light receiving sensors 62p, 62q, and 62r. ​​Therefore, even if the area of ​​light receiving sensors 62p, 62q, and 62r is small, light can be efficiently focused on light receiving sensors 62p, 62q, and 62r. ​​In addition, by reducing the area of ​​light receiving sensors 62p, 62q, and 62r, the capacitance of the input portion of amplifiers 26p, 26q, and 26r that amplify the output of light receiving sensors 62p, 62q, and 62r can be reduced. Therefore, the noise (N) of amplifiers 26p, 26q, and 26r can be reduced, so the S / N ratio of the optical device 10 for measurement can be improved.

[0073] Moreover, it is not a structure that uses a focusing lens system to focus light as shown in the past, so there is no need to increase the number of lenses of the focusing lens system, and the structure becomes simple. In addition, the focusing ability of the focusing lens system is lower than that of CPC63p, 63q, and 63r, and it can only focus light on an area of ​​the same degree as the emission area of ​​the optical fiber 55, so it is difficult to make all light beams reach the light receiving sensors 62p, 62q, and 62r. ​​However, in this embodiment, by using CPC63p, 63q, and 63r to focus light, even a small sensor area can be efficiently focused. In addition, an air layer is required between the emission surface of the focusing lens and the light receiving sensors 62p, 62q, and 62r for refraction, and it is impossible to fill the gap between CPC63p, 63q, and 63r and the light receiving sensors 62p, 62q, and 62r with an optical path bonding adhesive 64 as in this embodiment. Therefore, it is also impossible to correctly position and fix the focusing lens relative to the light receiving sensors 62p, 62q, and 62r. In contrast, in this embodiment, the space between CPCs 63p, 63q, 63r and light receiving sensors 62p, 62q, 62r is filled with optical path bonding adhesive 64. Therefore, CPCs 63p, 63q, 63r can be accurately positioned and fixed relative to light receiving sensors 62p, 62q, 62r.

[0074] When wire bonding is performed on the light receiving sensors 62p, 62q, and 62r, Figure 7 The above-mentioned operation may be carried out on a portion of the rectangular light receiving range SA except for the circular irradiation range LA.

[0075] In this way, the light beam emitted from the optical fiber 55 is focused by the CPCs 63p, 63q, and 63r to the light receiving range of the light receiving sensors 62p, 62q, and 62r. ​​Thus, 1 / 3 of the light beam incident on the optical fiber 55 (all light beams emitted from various parts of the measured area AR of the liquid crystal panel and below the maximum emission angle α with respect to the normal direction of the measured area AR) are incident on the light receiving sensors 62p, 62q, and 62r, respectively. Therefore, the amount of light received by the light receiving sensors 62p, 62q, and 62r does not decrease.

[0076] Next, refer to Figure 1 The structure of the measuring device main body 16 will be described in more detail. The measuring device main body 16 includes an A / D converter 31 , a data memory 32 , a display 33 , an operation unit 35 , a control unit 36 ​​, a power supply unit 37 , and a communication unit 38 .

[0077] The A / D conversion unit 31 converts the light receiving signal input from the measurement probe unit 14 into a digital signal (measurement data). The data memory 32 stores the measurement data output from the A / D conversion unit 31. The control unit 36 ​​controls the measurement operation by centrally controlling the operation of the measurement probe unit 14 and the operation of each unit in the measurement device main body 16. The control unit 36 ​​uses the measurement data stored in the data memory 32 to calculate the tristimulus values ​​(X, Y, Z), xyY (chromaticity coordinates, brightness), TΔuvY (correlated color temperature, color difference from the black body locus, brightness), etc. defined by CIE.

[0078] The display unit 33 displays the calculation results of 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 the external AC adapter (not shown) and supplies the power to each component via the control unit 36. The communication unit 38 outputs the calculation results of the control unit 36 ​​to the outside.

[0079] This application claims priority based on Japanese patent application No. 2022-169417 filed on October 21, 2022, the disclosure of which constitutes a part of this application as it is.

[0080] Industrial Applicability

[0081] The present invention can be utilized as a measuring optical device capable of measuring brightness, chromaticity, etc. of a measurement target object such as a display, for example.

[0082] (Explanation of symbols)

[0083] 10: tristimulus value type photoelectric colorimeter; 12: display surface; 14: measuring detector section; 16: measuring device main body; 21: objective lens; 24: beam splitting component; 25: photoelectric conversion section; 26: amplifier section; 26p, 26q, 26r: amplifiers; 27: measuring optical system; 28: light receiving system; 31: A / D conversion section; 32: data storage; 33: display section; 35: operation section; 36: control section; 37: power supply section; 38: communication section; 55: optical fiber; 55p, 55q, 55r: splitting part; 56p, 56q, 56r: collimating lens; 61p, 61q, 61r: spectral sensitivity correction filter; 62p, 62q, 62r: light receiving sensor; 63p, 63q, 63r: compound parabolic concentrator; 64: adhesive for optical path bonding; 65: sensor substrate; 66: holder; 611: parallel plate; 612: interference film; 631: incident surface; 632: exit surface.

Claims

1. An optical device for measurement, comprising: an objective optical system; and The plurality of types of photoelectric conversion units each receive only light in a predetermined wavelength range among the light from the objective optical system. in, Each of the photoelectric conversion units comprises: Filters use interference films to transmit only light in a predetermined wavelength range; a light receiving sensor that receives light transmitted through the filter, and whose output is amplified by an amplifier; and The compound parabolic concentrator is located between the filter and the light receiving sensor, and focuses the light transmitted through the filter to the light receiving sensor.

2. The optical measuring device according to claim 1, in, The compound parabolic concentrator is formed of a transparent material.

3. The optical measuring device according to claim 1 or 2, in, The surface of the compound parabolic concentrator facing the light receiving sensor is a plane, and the compound parabolic concentrator and the light receiving sensor are bonded together by an adhesive for optical path bonding.

4. The optical measuring device according to claim 1 or 2, in, The filter is formed by applying an interference film to the incident surface of a parallel plate.

5. The optical measuring device according to claim 1 or 2, in, The filter is formed by applying an interference film to the incident surface of a compound parabolic concentrator.

6. The optical measuring device according to claim 1 or 2, in, The measuring optical device includes an optical fiber for splitting the light from the objective optical system and guiding the split light to each photoelectric conversion unit, wherein the area of ​​an emission surface of the split optical fiber is larger than the area of ​​the light incident on the light receiving sensor.

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