Photometry device, photometry method, and correction system

Abstract

Provided are a photometry device, a photometry method, and a correction system that can solve the problem that a measured value cannot obtain linear continuity when a light attenuation member is not inserted into an optical path of light to be measured and when the light attenuation member is inserted into the optical path of the light to be measured. The present invention is provided with: a light receiving unit having one or more light receiving sensors (13b, 14b, 15b) for receiving light (2) to be measured from an object (1) to be measured; a control means (17) that calculates a measurement value on the basis of the output from the light-receiving sensor; a light attenuation member (40) that is provided in a pluggable manner in the optical path of the light to be measured (2) and that attenuates light incident on the light receiving unit; and a correction means for correcting the difference between the measured value calculated by the control means (17) in a state in which the light attenuation member (40) is inserted into the optical path and the measured value calculated by the control means (17) in a state in which the light attenuation member (40) is not inserted into the optical path, the measured value varying in accordance with the characteristics of the object to be measured (1).

Description

Technical Field

[0001] The present invention relates to a photometric device capable of measuring the brightness, chromaticity, etc. of light emitted from a measured object such as a display of a smartphone or a liquid crystal monitor, a photometric method, and a correction system for calibrating the photometric device. Background Art

[0002] As a photometric device such as the above, Fig.25 As shown in FIG. 1 , there is known a photometric device 100 including a branching optical system 120 for branching a light to be measured 201 from a measurement object 200 into a plurality of light beams (eg, Patent Document 1).

[0003] The photometric device includes an objective optical system 110 composed of a convex lens, etc., a branching optical system 120, and colorimetric optical systems 130 to 150. In the branching optical system 120, as an example, an optical fiber bundle is used. The optical fiber bundle is formed by bundling a plurality of bare optical fibers with small diameters, randomly branching them into a plurality of fibers (for example, three corresponding to the three stimulus values ​​of the color function X, Y, and Z specified by CIE (International Commission on Illumination)) at the output end (exit) side, and bundling each plurality of fibers. In addition, a diffuser is sometimes used as the branching optical system 120.

[0004] As the colorimetric optical systems 130 to 150 , for example, a number of combinations of wavelength selective filters and light receiving sensors as light receiving elements equal to the number of branches of the branching optical system 120 is used.

[0005] After the light received by each light receiving sensor is converted into an electrical signal, the corresponding electrical processing unit 161a to 161c performs I / V conversion, amplification and other processing, and inputs it as light receiving data to the control unit 162. The control unit 162 performs calculations based on the input light receiving data to calculate a measurement value.

[0006] However, in recent years, displays with a large luminance dynamic range have been used in smartphones and the like. Therefore, photometric devices are required to have the ability to measure from dark luminance to bright luminance when performing gamma inspection and adjustment.

[0007] Prior art literature

[0008] Patent Literature

[0009] Patent Document 1: Japanese Patent No. 5454675 Summary of the invention

[0010] Technical problem to be solved by the invention

[0011] In order to expand the dynamic range of the photometric device 100, it is necessary to control the amount of received light according to the constraints of the photoelectric conversion capability of the light receiving sensor (saturation of the light receiving sensor) and the design conditions of the electrical processing units 161a to 161c. Therefore, it is considered to insert or remove the light attenuation component according to the brightness of the object 200 in the optical path of the light 201 to be measured before it is emitted from the object 200 and enters the light receiving sensor.

[0012] However, if an optical attenuation component is inserted or removed in order to expand the dynamic range, errors caused by the insertion or removal of the optical attenuation component may occur when the reflectivity of the surface of the optical attenuation component on the side of the object to be measured is different from the internal reflectivity of the photometric device (reflection of the XYZ wavelength selection filter or the photosensor).

[0013] Therefore, in the calibration of the photometric device at the manufacturing factory (factory calibration), not only the correction coefficient when the light attenuation component is not inserted into the optical path is stored in the photometric device, but also the correction coefficient when the light attenuation component is inserted into the optical path is stored in the photometric device.

[0014] However, the inventors' experimental results show that, depending on the situation, the continuity of the linear line cannot be obtained in the measured values ​​when the light attenuation component is not inserted into the optical path or when it is inserted into the optical path, and a step difference occurs in the measured values ​​when the light attenuation component is inserted or removed.

[0015] The inventors have studied the cause and found that differences in properties of the measured object, such as surface reflectivity, have an influence.

[0016] The present invention has been completed in view of such technical background, and its object is to provide a photometric device, a photometric method and a correction system that can eliminate the problem that the measured value cannot obtain linear continuity in the state where the light attenuation component is not inserted into the optical path of the measured light and in the state where the light attenuation component is inserted into the optical path of the measured light, regardless of the differences in the characteristics of the measured object.

[0017] Technical solutions for solving technical problems

[0018] The above purpose is achieved through the following technical solutions.

[0019] (1) A light measuring device, comprising:

[0020] a light receiving unit having one or more light receiving sensors for receiving light to be measured from the object to be measured;

[0021] a control unit that calculates a measurement value based on an output from the light receiving sensor;

[0022] a light attenuation component, which is pluggable and disposed in the optical path of the light to be measured, and reduces the light incident on the light receiving part;

[0023] The correction unit corrects the difference between the measurement value calculated by the control unit in the state where the light attenuation component is inserted into the optical path and the measurement value calculated by the control unit in the state where the light attenuation component is not inserted into the optical path, which varies according to the characteristics of the object to be measured.

[0024] (2) The photometric device according to the above item (1),

[0025] The correction unit is a reflection member that is inserted into the optical path when the light attenuation member is inserted into the optical path, and is retracted from the optical path when the light attenuation member is retracted from the optical path.

[0026] (3) The photometric device according to the above item (2),

[0027] The reflective component is formed integrally with the light attenuating component.

[0028] (4) The photometric device according to the above item (2),

[0029] The reflecting component is a component different from the light attenuating component and is composed of one or more components.

[0030] (5) The photometric device according to any one of the above items (1) to (4),

[0031] The reflectivity of the reflective component is an optimum reflectivity of ±4%.

[0032] (6) The photometric device according to the above item (1),

[0033] The correction unit is composed of a control unit that calculates a measurement value using a correction coefficient corresponding to the physical property of the measurement object.

[0034] (7) The photometric device according to the above item (6),

[0035] A storage unit for storing the correction coefficient is provided.

[0036] (8) The photometric device according to the above item (6) or (7),

[0037] The control unit obtains, based on a user instruction, an output value output from the light receiving unit when the light attenuation member is inserted into the optical path and an output value output from the light receiving unit when the light attenuation member is not inserted into the optical path, and obtains the correction coefficient based on these.

[0038] (9) The photometric device according to the above item (8),

[0039] An exposure time for obtaining an output value output from the light receiving section in a state where the light attenuating member is inserted is longer than an exposure time for obtaining an output value output from the light receiving section in a state where the light attenuating member is not inserted.

[0040] (10) The photometric device according to the above item (8),

[0041] The correction coefficient is obtained when an output value output from the light receiving unit in a state where the light attenuation member is inserted into the optical path and an output value output from the light receiving unit in a state where the light attenuation member is not inserted into the optical path are within a predetermined range.

[0042] (11) The photometric device according to the above item (7),

[0043] The storage unit stores a plurality of correction coefficients corresponding to the plurality of objects to be measured, respectively.

[0044] (12) The photometric device according to the above item (6) or (7),

[0045] The characteristic of the object to be measured is the reflectivity of the object to be measured.

[0046] (13) A calibration system for calibrating the photometric device described in the preceding item (8), characterized in that:

[0047] The correction system includes an information processing device, and when the correction coefficient described in the above item (8) is set as a first correction coefficient, the information processing device requests the control unit to obtain the first correction coefficient based on a user's instruction, and

[0048] A request is made to further obtain a second correction coefficient based on a reference value of the object to be measured and an output value when the light receiving unit receives light from the object to be measured in a state where the light attenuation member is not inserted into the optical path.

[0049] (14) The correction system according to the above item (13),

[0050] After requesting to find the first correction coefficient, requesting to find the second correction coefficient.

[0051] (15) A calibration system for calibrating the photometric device described in the preceding item (8), characterized in that:

[0052] The correction system includes an information processing device, and when the correction coefficient described in the preceding item (8) is set as a first correction coefficient, the information processing device performs a process different from requesting the control unit to obtain the first correction coefficient based on a user's instruction.

[0053] There is a mode for requesting processing to obtain the second correction coefficient based on a reference value of the object to be measured and an output value when the light receiving unit receives light from the object to be measured in a state where the light attenuation member is not inserted into the optical path.

[0054] (16) A calibration system for calibrating the light measuring device described in the preceding item (8), characterized in that:

[0055] The calibration system includes an information processing device, and when the correction coefficient described in the preceding item (8) is set as a first correction coefficient, the information processing device performs processing different from requesting the control unit to calculate a second correction coefficient based on a reference value of the object to be measured and an output value when the light receiving unit receives light from the object to be measured in a state where the light attenuation component is not inserted into the optical path, based on an instruction from a user,

[0056] There is a mode for requesting only the process of finding the first correction coefficient.

[0057] (17) In the photometric device according to any one of the above items (1), (2), (6) or (7), the light attenuating member is inserted and removed according to the brightness of the object to be measured.

[0058] (18) According to any one of the above items (1), (2), (6) or (7), the light receiving sensor is a silicon sensor.

[0059] (19) The photometric device according to any one of the above items (1), (2), (6) or (7), further comprising a wavelength selective filter in front of the light receiving sensor.

[0060] (20) According to any one of the above items (1), (2), (6) or (7), the wavelength selective filter is a thin film filter.

[0061] (21) According to any one of the above items (1), (2), (6) or (7), the light attenuating component is composed of a thin film filter.

[0062] (22) The photometric device according to any one of the above items (1), (2), (6) or (7), further comprising a branching optical system for branching the light to be measured into a plurality of light beams.

[0063] (23) According to any one of the above items (1), (2), (6) or (7), the measurement wavelength range of the light to be measured is a visible light region.

[0064] (24) According to any one of the above items (1), (2), (6) or (7), the wavelength selection filter is a color function filter.

[0065] (25) According to any one of the above items (1), (2), (6) or (7), the wavelength selection filter is a spectral filter and the light receiving sensor is a line sensor.

[0066] (26) A light measuring method of a light measuring device, characterized in that:

[0067] The light measuring device has:

[0068] a light receiving unit having one or more light receiving sensors for receiving light to be measured from the object to be measured;

[0069] a control unit that calculates a measurement value based on an output from the light receiving sensor,

[0070] A light attenuation component is inserted or removed from an optical path of the light to be measured in the photometric device, and a difference between a measurement value calculated by the control unit in a state where the light attenuation component is inserted into the optical path and a measurement value calculated by the control unit in a state where the light attenuation component is not inserted into the optical path, which varies according to characteristics of the object to be measured, is corrected.

[0071] (27) A correction system for correcting the light measuring device described in the preceding item (8) for each display color used as a reference, characterized in that:

[0072] The correction coefficient is obtained by switching the insertion and removal of the light attenuating member while the reference display color is fixed.

[0073] (28) A calibration system for calibrating the light measuring device described in the preceding item (8), characterized in that:

[0074] When saturation of the light receiving sensor in the light measuring device is detected during the process of obtaining the correction coefficient, the brightness of the object to be measured is reduced.

[0075] Effects of the Invention

[0076] According to the photometric device and the photometric method of the present invention, a light attenuation component is provided in an insertable manner in the optical path of the light to be measured and reduces the light incident on the light receiving part, and the difference between the measured value calculated by the control unit in the state where the light attenuation component is inserted in the optical path and the measured value calculated by the control unit in the state where the light attenuation component is not inserted in the optical path, which varies according to the characteristics of the object to be measured, is corrected. Therefore, regardless of the difference in the characteristics of the object to be measured, the continuity of the straight line can be ensured in the measured value in the state where the light attenuation component is not inserted in the optical path of the light to be measured and in the state where the light attenuation component is inserted in the optical path of the light to be measured. As a result, measurement with a large dynamic range and less error can be performed.

[0077] According to the calibration system of the present invention, regardless of differences in surface characteristics of the object to be measured, calibration can be performed to ensure continuity of the straight line in the measured value when the light attenuation member is not inserted in the optical path of the measured light or when the light attenuation member is inserted in the optical path of the measured light. BRIEF DESCRIPTION OF THE DRAWINGS

[0078] Figure 1 This is a block diagram showing the internal structure of the photometric device according to the first embodiment of the present invention.

[0079] Figure 2 This is an explanatory diagram of a light attenuation component using a thin film filter.

[0080] Figure 3 (A) is a schematic diagram for explaining the reflection of incident light by an interference film filter used as a wavelength selective filter. Figure 3 (B) is a graph of the transmittance and reflectance of the interference film filter.

[0081] Figure 4 (A) is a schematic diagram for examining the situation when the light to be measured from the glare type object to be measured enters the measuring optical unit of the photometric device in a state where the light attenuation component is not inserted in the optical path of the light to be measured, Figure 4 (B) is a schematic diagram for examining a state in which a light attenuating member is inserted into the optical path of the light to be measured.

[0082] Figure 5 (A) Figure 5 (B) is a graph showing an example of the transmittance and reflectance in the visible light region (wavelength 380 to 780 nm) of a light attenuating member composed of a thin film filter whose thin film is a chromium oxide film.

[0083] Figure 6 (A) is a schematic diagram for examining the situation when the light to be measured from the non-glare type object to be measured enters the measuring optical unit of the photometric device in a state where the light attenuation component is not inserted into the optical path of the light to be measured, Figure 6 (B) is a schematic diagram for examining a state in which a light attenuating member is inserted into the optical path of the light to be measured.

[0084] Figure 7 This is a graph for explaining measurement errors.

[0085] Figure 8 (A) is a schematic diagram for examining the situation when the light to be measured from a glare type object to be measured enters the measuring optical unit of the photometric device in a state where a light attenuation component with high surface reflectivity is used and the light attenuation component with high surface reflectivity is not inserted into the optical path of the light to be measured. Figure 8(B) is a schematic diagram for examining a state in which a light reduction member is inserted into the optical path of the light to be measured.

[0086] Fig. 9 (A) is used to examine the situation when the light to be measured from the non-glare type object to be measured is incident on the measuring optical unit of the photometric device when a light attenuation component with high surface reflectivity is used and the surface reflectivity is not inserted into the optical path of the light to be measured. Fig. 9 (B) is a schematic diagram showing a state in which a light reduction member is inserted into the optical path of the light to be measured.

[0087] Fig.10 (A) Fig.10 (B) is a diagram for explaining an example of a method for measuring the pass rate and the return rate.

[0088] Fig.11 (A) is a graph showing the transmittance in the visible light region of a light attenuating component composed of a thin film filter whose thin film is a niobium oxide film. Fig.11 (B) is a graph showing the reflectivity in the visible light region of a light attenuating member composed of three types of thin film filters, namely, niobium oxide film 1, niobium oxide film 2, and niobium oxide film 3.

[0089] Fig.12 (A) Fig.12 (B) Fig.12 (C) is a graph showing the transmittance of a light attenuating member composed of a glass absorption filter in the visible light region, the reflectance when a single-layer antireflection film is formed, and the reflectance when there is no antireflection film but only a protective film.

[0090] Fig.13 This is a structural diagram of a light measuring device according to Modification 1.

[0091] Fig.14 This is an explanatory diagram of a case where the objective optical system is front telecentric.

[0092] Fig.15 This is a structural diagram of the light measuring device of Modification Example 2.

[0093] Fig.16 This is a structural diagram of the light measuring device of Modification Example 3.

[0094] Fig.17 This is a structural diagram of the light measuring device of variant example 4.

[0095] Fig.18 This is a structural diagram of the light measuring device of variant example 5.

[0096] Fig.19 (A) Fig.19 (B) Fig.19(C) is a graph showing the transmittance of a transparent glass in the visible light region, the reflectance in a state where a single-layer antireflection film is formed, and the reflectance in a state where there is no antireflection film but only a protective film.

[0097] Fig. 20 This is a structural diagram of the light measuring device of variant example 6.

[0098] Fig.21 This is a flowchart for explaining a method for controlling insertion and removal of a light attenuating component implemented by a photometric device.

[0099] Fig. 22 It is an overall structural diagram of the correction system according to the second embodiment of the present invention.

[0100] Fig.23 It is a block diagram showing the details of the control unit.

[0101] Fig.24 (A) Fig.24 (B) is a flowchart showing a calculation process performed by the control unit when calculating tristimulus values ​​(X, Y, Z).

[0102] Fig.25 1 is a flowchart showing a calculation process when tristimulus value calculation is performed using the ND conversion user correction coefficient Un.

[0103] Fig.26 This is the correction coefficient calculation mode selection screen.

[0104] Fig. 27 This is a diagram for explaining a state in which a plurality of types of ND conversion user correction coefficients Un are stored.

[0105] Fig.28 This is a block diagram showing a general structure of a light measuring device. DETAILED DESCRIPTION

[0106] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0107] [Implementation Method 1]

[0108] <Overall structure>

[0109] Figure 1 This is a block diagram showing the structure of a tristimulus value type photometric device according to one embodiment of the present invention.

[0110] exist Figure 1 In the embodiment, the photometric device 10 is used, for example, in an inspection process of a production line for smartphone displays, and measures brightness or chromaticity of a display surface of a display as a measurement target 1 .

[0111] The photometric device 10 includes an objective optical system 11, a branching optical system 12, colorimetric optical systems 13 to 15, and a light attenuating member 40. The objective optical system 11 uses a convex lens 11a having positive refractive power, and the branching optical system 12 uses a diffuser plate 20 having branching and diffusing functions.

[0112] An aperture stop 11b is disposed at the rear focal position of the convex lens 11a, and is a front telecentric optical arrangement in order to take in a component within a predetermined angle (e.g., ±2.5 degrees) relative to the normal line of the display surface, i.e., the measured surface, of the measured object 1. The diffuser 20 is disposed at the rear of the aperture stop 11b surface.

[0113] A light attenuation component 40 is disposed between the convex lens 11a and the diffuser plate 20, that is, in front of the aperture stop 11b surface. The light attenuation component 40 is driven by an insertion and extraction device 50 as a driving device to be inserted into or withdrawn from the optical path of the measured light 2. The insertion and extraction device 50 is constituted by, for example, a linear actuator. When the light attenuation component 40 is inserted into the optical path of the measured light 2, the amount of the measured light 2 incident on the diffuser plate 20 is reduced by the light attenuation component 40. When the light attenuation component 40 is withdrawn from the optical path of the measured light 2, the measured light 2 is incident on the diffuser plate 20 without reducing the amount of light. It should be noted that in the following description, the "light attenuation component" is also referred to as a "light reduction component" or an "ND filter".

[0114] The light reduction member 40 is inserted and removed according to the brightness of the object 1 to be measured. Specifically, it is in a retracted state when the object 1 to be measured is dark, and is inserted into the optical path when the object 1 to be measured is bright, thereby reducing the amount of light to prevent the saturation of the light receiving sensors 13b, 14b, and 15b. As a result, the intensity of the light 2 to be measured can be set within the dynamic range of the light receiving sensors 13b, 14b, and 15b, resulting in an expansion of the dynamic range of the light measuring device 10.

[0115] The dimming component 40 is preferably arranged near the focusing position (the position of the aperture stop 11b) of the objective optical system 11. In the light receiving optical path of the measured light 2, the effective optical path at the aperture stop position is small. The smaller the effective optical path, the smaller the size of the dimming component 40 can be, the smaller the plug-in device 50 can be, and the driving torque can also be low torque. Therefore, the product size becomes compact and light, and the cost becomes low. It should be noted that the aperture stop 11b may not be provided.

[0116] In this embodiment, the dimming member 40 needs to have a transmissive reflective member on its surface. This will be described later. As long as it has a reflective member, various members such as a thin film filter, a glass absorption filter, a porous plate, etc. can be used.

[0117] However, it is very important that the light attenuation component 40 has spectral flatness (uniformity). This is because flatness affects the spectral responsivity in the plug-in and unplug states of the light attenuation component 40 (with or without the light attenuation component 40). In the case of unevenness, the light receiving spectrum sensitivity when there is no light attenuation component 40 (withdrawn from the optical path) and the light receiving spectrum sensitivity when there is the light attenuation component 40 (inserted into the optical path) will change. If the light receiving spectrum sensitivity deviates from the isochromatic function, it will become an error in luminance and chromaticity. In addition, it is also very important that there is no change caused by ambient temperature, etc.

[0118] The spectral flatness of the glass absorption filter is poor, and the transmittance change caused by the ambient temperature is also large. Although the porous plate has spectral flatness, it produces uneven measurement at the light receiving angle. And strict position reproducibility is required. The spectral flatness of the thin film filter is good, and the reliability based on the ambient temperature is also high. Therefore, the thin film filter can be used as the light attenuation component 40.

[0119] Figure 2 An example of the light attenuation member 40 using a thin film filter is shown.

[0120] Reference Figure 2 The light attenuation component 40 includes films 42, 43 and a transparent substrate 41 supporting the films 42, 43. The transparent substrate 41 is formed of an optical material such as glass, plastic, crystal or sapphire that is transparent to the measured light 2. The transparent optical material forming the transparent substrate 41 can be appropriately selected according to the wavelength range of the measured light 2.

[0121] The thin films 42 and 43 are respectively formed on at least one of the incident surface 41a and the exit surface 41b of the corresponding transparent substrate 41. Specifically, the light attenuating member 40 includes at least one of the thin films 42 and 43. The thin film 42 is formed on the incident surface 41a of the transparent substrate 41. The thin film 43 is formed on the exit surface 41b of the transparent substrate 41. Specifically, the thin films 42 and 43 are formed on both the 41a and the exit surface 41b of the corresponding transparent substrate 41.

[0122] Specifically, the light attenuation member 40 includes a thin film 42 formed on the incident surface 41a of the transparent substrate 41 and a thin film 43 formed on the emission surface 41b of the transparent substrate 41. The thin films 42 and 43 may have the same film structure as each other or may have different film structures from each other. The thin films 42 and 43 may be formed of the same material as each other or may be formed of different materials. For example, the material of the thin films 42 and 43 may be SiO 2 MgF 2 The interference film of such dielectric material may also be made of Al 2 O 3 、TiO 2 , Nb 2O 5 Alternatively, a metal material such as Cr or Nb may be used.

[0123] As the light attenuation component 40, an absorption-type light attenuation component that absorbs light inside a substrate (e.g., a glass substrate) is known. The degree of freedom in designing the transmission spectrum of the absorption-type light attenuation component is relatively low. In addition, the stability of the absorption-type light attenuation component with respect to the ambient temperature and the ambient humidity is relatively low. In contrast, the degree of freedom in designing the transmission spectrum of the interference-type light attenuation component (e.g., the light attenuation component 40 including the thin films 42 and 43 formed of interference films) is relatively high. In addition, the stability of the interference-type light attenuation component with respect to the ambient temperature and the ambient humidity is relatively high.

[0124] The colorimetric optical systems 13, 14, 15 include isochromatic function filters, i.e., wavelength selection filters (also referred to as color filters in the following description) 13a, 14a, 15a corresponding to the three stimulus values ​​X, Y, Z, respectively, and light receiving elements, i.e., light receiving sensors 13b, 14b, 15b, used in combination with them.

[0125] The color filters 13a, 14a, and 15a can also be formed by stacking a plurality of light absorption filters so that the incident light has a transmittance corresponding to the desired spectral characteristics of the three stimulus values ​​X, Y, and Z. However, in such a structure, there is a problem that it is impossible to design a filter with transmittance peaks in two wavelength regions, that is, the degree of freedom in filter design is small. In addition, light absorption filters also have the problem of low transmittance and large light loss. In addition, especially in film-shaped color filters, there is also a problem of drastic changes over the years (poor stability) with respect to heat, light (ultraviolet rays), humidity, etc.

[0126] Therefore, it is preferable to use interference filters (hereinafter referred to as interference film filters) instead of light absorption filters for the color filters 13a, 14a, and 15a. The interference film filter is a filter formed by laminating dozens of layers of dielectrics or oxides on a glass substrate by vacuum evaporation or sputtering, and is a wavelength-selective filter that transmits or reflects light by interference.

[0127] Therefore, compared with the above-mentioned light absorption type filter, the interference film filter can easily obtain the desired transmittance (that is, it is easy to design and has a high degree of freedom in design), and can also produce a filter with two peaks (mountains) such as the isochromatic function X. In addition, since the interference film filter has a high transmittance, for example, the peak transmittance is less than 50% in the absorption type, while it is close to 100% in the interference type. In addition, the interference film filter has the advantage of excellent reliability (little change in transmittance over time due to temperature, humidity, and exposure).

[0128] The interference film filters used as the color filters 13a, 14a, and 15a have almost no absorption by the film material (dielectric). Figure 3 As shown in (A), light rays other than the transmitted light rays among the incident light rays (light rays to be measured) are reflected by each layer and become reflected light rays.

[0129] Figure 3 (B) is a graph showing the transmittance and reflectance of an interference film filter as an X-ray filter. In this graph, the black portion inside the characteristic curve of transmittance versus wavelength corresponds to transmitted light, and the white portion outside corresponds to reflected light, and transmittance + reflectance ≒ 100%.

[0130] In this embodiment, silicon sensors are used as the light receiving sensors 13b, 14b, and 15b.

[0131] The light received by each light receiving sensor 13b, 14b, 15b is converted into an electric signal, and after I / V conversion and amplification by the corresponding electric processing unit 16a, 16b, 16c, the signal is input as light receiving data to the control unit 17. The control unit 17 performs calculations based on the input light receiving data to calculate the measured value.

[0132] However, as described in the problem to be solved by the invention, the inventors have found the following technical problem: when the dimming component 40 is inserted or removed from the optical path of the measured light 2, the measured value cannot obtain linear continuity due to the difference in the surface reflectivity of the measured object 1. First, this problem is described.

[0133] <Problems that occur when inserting and removing the light reduction component 40>

[0134] like Figure 4 As shown in the schematic diagram in (A), when the dimming member 40 is not inserted into the optical path of the measured light 2 (retracted from the optical path), the dimming member 40 is not inserted into the optical path of the measured light 2 (retracted from the optical path), Figure 4 The following describes the situation when the measured light 2 (referred to as "DUT" in (A)) 1 enters the measuring optical unit of the photometric device 10. The measuring optical unit includes a branching optical system 12 and colorimetric optical systems 13 to 15. Figure 4 In the specification, they are collectively referred to as "optical components". In addition, part of the light incident on the optical component 90 is transmitted through the branch optical system 12 and the color filters 13a, 14a, 15a in the optical component 90 and is received by the light receiving sensors 13b, 14b, 15b. In addition, part of the light is reflected by the surface of the color filters 13a, 14a, 15a or the light receiving sensors 13b, 14b, 15b, and is transmitted through the optical component 90 in the reverse direction and returns to the side of the object 1 to be measured.

[0135] Here, among the measured light 2 incident on the optical component 90, the proportion of light that passes through the optical component 90 and is finally received by the light receiving sensors 13b, 14b, and 15b is called the transmission rate, the proportion of light that is reflected and transmitted through the optical component and returns to the side of the measured object 1 is called the return rate, and the light that returns to the side of the measured object 1 and the light that is reflected again by the measured object 1 and returns to the optical component are called return light.

[0136] Furthermore, a display with a high surface reflectivity among the object to be measured 1 is referred to as a glare type object to be measured or simply as glare. Generally, the regular reflectivity is about 5%. On the other hand, a display with a low surface reflectivity among the object to be measured 1 is referred to as a non-glare type object to be measured or simply as non-glare. Generally, the regular reflectivity is about 1%. Furthermore, there are more glare types among smartphones, and more non-glare types among personal computer displays.

[0137] exist Figure 4 In the schematic diagram of (A), glare with a reflectivity of 5% is used as the measured object 1, and the intensity of the incident light emitted from the measured object 1 and incident on the photometric device 10 is set to 100. In addition, the transmission rate of the optical component 90 of the photometric device 10 is set to 90%, and the return rate is set to 10%.

[0138] Under this condition, when incident light = 100 is incident on the optical component 90, the transmittance of the optical component 90 = 90%, and therefore, the light receiving amount 1 of the light receiving sensors 13b, 14b, and 15b = 90. On the other hand, since the return rate of the optical component 90 = 10%, the return light 1 = 10. This return light 1 is reflected by the surface of the object 1 to be measured with a reflectivity of 5%, and returns to the optical component of the photometric device 10 as return light 2 = 0.5.

[0139] The return light 2 passes through the optical component 90 and is received by the light receiving sensors 13 b , 14 b , and 15 b , with the light receiving amount 2 being 0.45.

[0140] A part of the return light 2 is reflected by the optical component 90 and returns to the object 1 to be measured. Although it is repeatedly reflected between the object 1 to be measured and the optical component 90, the intensity gradually decreases, so it is ignored.

[0141] The sum of the light receiving amount 1 and the light receiving amount 2 of the light receiving sensors 13b, 14b, and 15b = 90.45. Therefore, the light receiving amount caused by the reflection of the optical component 90 and the surface reflection of the measured object 1, that is, the ratio of the light receiving amount 2 to the light receiving amount 1, in other words, the light receiving amount increased by the influence of multiple reflections = 0.45 / 90 = 0.5%.

[0142] Next, use Figure 4The schematic diagram (B) considers the situation when the light 2 to be measured is incident on the photometric device 10 in a state where the light reduction member 40 is inserted in the optical path of the light 2 to be measured in front of the optical member 90 (between the object 1 to be measured and the optical member 90 ).

[0143] exist Figure 4 In (B), the object 1 and the optical component 90 are set to Figure 4 (A) is the same. The light reduction member 40 has a transmittance of 5% and a reflectance of 2%. The light reduction member 40 corresponds to a thin film filter of a chromium oxide film. Figure 5 (A) represents the transmittance of the thin film filter with chromium oxide film, Figure 5 (B) shows the reflectance of the thin film filter of the chromium oxide film. The average transmittance in the visible light region (380 nm to 780 nm) is 5%, and the average reflectance is 2%.

[0144] Under this condition, when the incident light = 100 from the object to be measured 1 is incident on the photometric device 10, the light that has passed through the dimming component 40 and the optical component 90 is received by the light receiving sensors 13b, 14b, and 15b as the light receiving amount 1 = 4.5. In addition, the light reflected by the optical component 90 returns to the object to be measured 1 via the dimming component 40 (return light 1 = 0.03). The light that is incident from the object to be measured 1 and reflected by the dimming component 40 also returns to the object to be measured 1 (return light 3 = 2.00). The return light 1 and 3 that have returned to the object to be measured 1 are reflected by the surface of the object to be measured 1, become return light 2 = 0.101, and transmit through the dimming component 40 again to enter the optical component 90, and are received by the light receiving sensors 13b, 14b, and 15b as the light receiving amount 2 = 0.00456.

[0145] The sum of the light receiving amount 1 and the light receiving amount 2 of the light receiving sensors 13b, 14b, and 15b = 4.504556. Therefore, the light receiving amount caused by the reflection of the optical component 90 and the surface reflection of the measured object 1, that is, the ratio of the light receiving amount 2 to the light receiving amount 1, in other words, the light receiving amount increased by the influence of multiple reflections = 0.00456 / 4.5 = 0.1%.

[0146] If Figure 4 (A) shows a case where the light reduction component 40 is not inserted into the optical path and Figure 4 Compared with the case where the dimming component 40 shown in (B) is inserted into the optical path, the amount of light received due to the influence of multiple reflections is increased by 0.5% and 0.1%, with a difference of 0.4%. When the dimming component 40 is inserted, the return light 1 from the optical component 90 passes through the dimming component 40 twice and reaches the light receiving sensors 13b, 14b, and 15b. Since it passes through the dimming component 40 twice, the intensity of the return light is reduced. On the other hand, although the reflection amount of the dimming component 40 (return light 3) is added, the intensity is still higher than that of the optical component 90. Figure 4The return light 1 of A is low.

[0147] Then, if Figure 6 As shown in the schematic diagram of (A), a non-glare object 1 is used to examine the state of the measured light 2 when the dimming component 40 is not inserted into the optical path. The reflectivity of the object 1 is set to 1%. In addition, the pass rate and return rate of the optical component 90 are set to the same as Figure 4 (A) Figure 4 The optical component 90 used in (B) is the same.

[0148] Under this condition, when the incident light = 100 from the object to be measured 1 is incident on the photometric device 10, the light passing through the optical component 90 is received by the light receiving sensors 13b, 14b, and 15b as the received light quantity 1 = 90. In addition, the light reflected by the optical component 90 returns to the object to be measured 1 (returned light 1 = 10). The returned light 1 is reflected by the surface of the object to be measured 1, becomes returned light 2 = 0.1, and is incident on the optical component 90 again, and is received by the light receiving sensors 13b, 14b, and 15b as the received light quantity 2 = 0.09.

[0149] The sum of the light receiving amount 1 and the light receiving amount 2 of the light receiving sensors 13b, 14b, and 15b = 90.09. Therefore, the light receiving amount caused by the reflection of the optical component 90 and the surface reflection of the measured object 1, that is, the ratio of the light receiving amount 2 to the light receiving amount 1, in other words, the light receiving amount increased by the influence of multiple reflections = 0.09 / 90 = 0.10%.

[0150] Next, use Figure 6 The schematic diagram (B) considers the situation when the light 2 to be measured is incident on the photometric device 10 in a state where the dimming member 40 is inserted in the optical path of the light 2 to be measured in front of the optical member 90 (between the object 1 to be measured and the optical member 90 ).

[0151] exist Figure 6 In (B), the object 1 and the optical component 90 are set to Figure 6 (A) is the same. For the light reduction member 40, the transmittance is 5% and the reflectance is 2%.

[0152] Under this condition, when the incident light = 100 from the object to be measured 1 is incident on the photometric device 10, the light that has passed through the dimming component 40 and the optical component 90 is received by the light receiving sensors 13b, 14b, and 15b as the light receiving amount 1 = 4.5. In addition, the light reflected by the optical component 90 returns to the object to be measured 1 via the dimming component 40 (return light 1 = 0.03). The light that was incident from the object to be measured 1 and reflected by the dimming component 40 also returns to the object to be measured 1 (return light 3 = 2.00). The return light 1 and 3 that returned to the object to be measured 1 is reflected by the surface of the object to be measured 1, becomes the return light 2 = 0.020, and transmits through the dimming component 40 again and is incident on the optical component, and is received by the light receiving sensors 13b, 14b, and 15b as the light receiving amount 2 = 0.00091.

[0153] The sum of the light receiving amount 1 and the light receiving amount 2 of the light receiving sensors 13b, 14b, and 15b = 4.500911. Therefore, the light receiving amount caused by the reflection of the optical component 90 and the surface reflection of the measured object 1, that is, the ratio of the light receiving amount 2 to the light receiving amount 1, in other words, the light receiving amount increased by the influence of multiple reflections = 0.0091 / 4.5 = 0.02%.

[0154] Will Figure 6 (A) shows a state where a non-glare type object to be measured 1 is used and the light reduction member 40 is not inserted into the optical path. Figure 6 In comparison with the state shown in (B) where the non-glare type object to be measured 1 is used and the light reduction member 40 is inserted into the optical path, the increase in the amount of received light due to the influence of multiple reflections is 0.10% and 0.02%, with a difference of 0.08%.

[0155] Next, the relationship between the calibration light source and the object 1 to be measured will be examined.

[0156] When the calibration light source and the object 1 are of the same type, no absolute value error occurs when the ND filter 40 is present (inserted) or not (not inserted). Therefore, no deviation (linear error) in the measured value occurs when the ND filter 40 is inserted or removed.

[0157] Here, the "absolute value error" and the "linear error" are explained.

[0158] “Absolute value error” refers to the error of brightness or chromaticity with respect to the “true value.” In many cases, the value measured by a high-precision photometric device (eg, a spectrophotometer) serving as a reference is used as the “true value.”

[0159] The cause of the absolute value error is the inconsistency of the color function of the XYZ filter pair, the difference in the measurement geometry (aperture angle), etc. In the case of brightness, for example, an absolute value error of <±2% is set as the product specification of the photometric device 10 .

[0160] Linear error refers to an error that fails to ensure the continuity of the measured value from low luminance to high luminance. When performing "gamma measurement" on a smartphone, etc., the luminance chromaticity is measured while continuously changing the brightness from low luminance (low grayscale) to high luminance (high grayscale).

[0161] At this time, if Figure 7 As shown by the dotted line, the brightness of the light source and the measured luminance value must be a linear function. As a linear error, there are distortion and step difference as shown by the solid line in the figure. Linear distortion is caused by the light receiving sensors 13b, 14b, 15b or electrical processing. The linear step difference is caused by the change of the amplification factor in the electrical processing and the insertion and removal of the ND filter 40. In the case of the luminance value, for example, the linear error <±0.2% is set as the product specification of the light measuring device 10. Hereinafter, the linear error of the step difference type is referred to as the linear error (ND step difference).

[0162] On the other hand, when the calibration light source and the object 1 are of different types, Figure 4 (A)(B), Figure 6 The results shown in (A) and (B) are that the absolute value error is -0.4% when there is no ND filter 40 (abbreviated as "no ND"), and the absolute value error is -0.08% when there is the ND filter 40 (abbreviated as "with ND"), and the linear error (ND step difference) is +0.32%.

[0163] Specifically,

[0164] (1) When using a glare-type light source for calibration

[0165] Without ND correction factor: Knon = incident light / received light = 100 / 90.45

[0166] With ND correction factor: Knd = incident light / received light = 100 / 4.50456

[0167] The measured value of the glare type object 1 after correction by the correction count is:

[0168] No-ND measurement value = light intensity × No-ND correction factor = 90.45 × 100 / 90.45 = 100 (absolute value error 0%)

[0169] ND measured value = light intensity × ND correction factor = 4.50456 × 100 / 4.50456 = 100 (absolute value error 0%)

[0170] The difference in measured values ​​with and without ND (with ND - without ND) = 100 - 100 = 0 (linear error (ND step difference) 0%),

[0171] On the other hand, the measured values ​​of the non-glare type object 1 are:

[0172] No-ND measurement value = light intensity × No-ND correction factor = 90.09 × 100 / 90.45 = 99.602 (absolute value error - 0.4%)

[0173] ND measurement value = light intensity × ND correction factor = 4.50091 × 100 / 4.50456 = 99.919 (absolute value error - 0.08%)

[0174] The difference in measured values ​​with and without ND (with ND - without ND) = 99.919 - 99.602 = 0.3170 (linear error (ND step difference) + 0.32%)

[0175] (2) When using a non-glare light source for calibration

[0176] In this case, the opposite situation to the case of using a glare type light source for correction occurs. In the measured value of the glare type object 1, an absolute error of +0.4% without ND and +0.08% with ND occurs, and a linear error (ND step) of -0.32% occurs.

[0177] (3) Relationship with the specifications of the light measuring device (accuracy required by the customer)

[0178] In the above example, the absolute value error (without ND -0.4%, with ND -0.08%) is smaller than the product specification (±2%), so it is not a problem. However, the linear error (ND step difference) of +0.32% is larger than the product specification (±0.2%), so it is a problem.

[0179] In this way, regardless of whether the object 1 to be measured is glare or non-glare, in other words, due to the difference in the surface reflection characteristics of the object 1 to be measured, a linear error (ND step) occurs when the dimming component 40 is inserted or removed.

[0180] <Solution>

[0181] like Figure 8 As shown in (A) and (B), as the dimming member 40, a member having a reflective member on the front surface, that is, the surface on the side of the object to be measured 1, is used. Figure 4 (A)(B) and Figure 6 (A)(B) The case of the measured light 2 is considered in the same manner.

[0182] Glare light with a reflectivity of 5% was used as the object to be measured 1, and the intensity of the incident light was set to 100. Furthermore, the transmission rate of the optical component 90 of the photometric device 10 was set to 90%, and the return rate was set to 10%.

[0183] Figure 8(A) is a schematic diagram showing a state where the dimming component 40 is not inserted into the optical path of the measured light 2. Figure 4 (A) is the same, so the amount of light received 1 = 90, the amount of light received 2 = 0.45, and the total amount of light received 1 and the amount of light received 2 = 90.45. Therefore, the amount of light received due to the reflection of the optical component 90 and the surface reflection of the measured object 1, that is, the ratio of the amount of light received 2 to the amount of light received 1, in other words, the amount of light received increased due to the influence of multiple reflections = 0.45 / 90 = 0.5%.

[0184] Figure 8 (B) is a schematic diagram showing a state where the dimming member 40 having a reflective member on its surface is inserted into the optical path of the measured light 2. The dimming member 40 has a transmittance of 5% and a reflectance of 10%, which is the same as the return rate of the optical member 90.

[0185] Under this condition, when the incident light = 100 from the object to be measured 1 is incident on the photometric device 10, the light that has passed through the dimming component 40 and the optical component 90 is received by the light receiving sensors 13b, 14b, and 15b as the received light quantity 1 = 4.5. In addition, the light reflected by the optical component 90 returns to the object to be measured 1 via the dimming component 40 (returned light 1 = 0.03). The light that was incident from the object to be measured 1 and reflected by the dimming component 40 also returns to the object to be measured 1 (returned light 3 = 1.00). The returned light 1 and 3 that returned to the object to be measured 1 are reflected by the surface of the object to be measured 1, become returned light 2 = 0.501, and transmit through the dimming component 40 again to enter the optical component 90, and are received by the light receiving sensors 13b, 14b, and 15b as the received light quantity 2 = 0.02256.

[0186] The sum of the light receiving amount 1 and the light receiving amount 2 of the light receiving sensors 13b, 14b, and 15b = 4.5225564. Therefore, the light receiving amount caused by the reflection of the optical component 90 and the surface reflection of the measured object 1, that is, the ratio of the light receiving amount 2 to the light receiving amount 1, in other words, the light receiving amount increased by the influence of multiple reflections = 0.02256 / 4.5 = 0.5%.

[0187] Will Figure 8 (A) shows a case where the light reduction member 40 is not inserted and Figure 8 In comparison with the case where the light reduction member 40 is inserted as shown in (B), the increase in the amount of received light due to the influence of multiple reflections is 0.5%, which is the same value.

[0188] Then, if Fig. 9 As shown in the schematic diagram of (A), a non-glare object 1 is used to examine the state of the measured light when the dimming component 40 is not inserted into the optical path. The reflectivity of the object 1 is 1%. In addition, the pass rate and return rate of the optical component 90 are set to be the same as Figure 6(A) The optical component 90 used is the same. Figure 6 (A) is the same, so the amount of light received 1 = 90, the amount of light received 2 = 0.09, and the total amount of light received 1 and the amount of light received 2 = 90.09. Therefore, the ratio of the amount of light received 2 caused by the reflection of the optical component and the surface reflection of the measured object 1 to the amount of light received 1, in other words, the amount of light received increased due to the influence of multiple reflections = 0.09 / 90 = 0.10%.

[0189] Fig. 9 (B) is a schematic diagram showing a state where the light reduction member 40 is inserted into the optical path of the light 2 to be measured. Figure 8 (B) is the same, the transmittance is 5%, and the reflectance is 10%, which is the same as the return rate of the optical component 90.

[0190] Under this condition, when the incident light = 100 from the object to be measured 1 is incident on the photometric device 10, the light that has passed through the dimming component 40 and the optical component 90 is received by the light receiving sensors 13b, 14b, and 15b as the light receiving amount 1 = 4.5. In addition, the light reflected by the optical component 90 returns to the object to be measured 1 via the dimming component 40 (return light 1 = 0.03). The light that was incident from the object to be measured 1 and reflected by the dimming component 40 also returns to the object to be measured 1 (return light 3 = 1.00). The return light 1 and 3 that returned to the object to be measured 1 are reflected by the surface of the object to be measured 1, become return light 2 = 0.100, and transmit through the dimming component 40 again to enter the optical component 90, and are received by the light receiving sensors 13b, 14b, and 15b as the light receiving amount 2 = 0.00451.

[0191] The sum of the light receiving amount 1 and the light receiving amount 2 of the light receiving sensors 13b, 14b, and 15b = 4.504511. Therefore, the light receiving amount caused by the reflection of the optical component 90 and the surface reflection of the measured object 1, that is, the ratio of the light receiving amount 2 to the light receiving amount 1, in other words, the light receiving amount increased by the influence of multiple reflections = 0.00451 / 4.5 = 0.1%.

[0192] Will Fig. 9 (A) shows a case where the light reduction member 40 is not inserted and Fig. 9 In comparison with the case where the light reduction member 40 is inserted as shown in (B), the increase in the amount of received light due to the influence of multiple reflections is 0.1% and is the same value.

[0193] It can be understood from this that by forming a reflective member with a reflectivity of 10% on the light reduction member 40, the difference in the amount of light received due to the influence of multiple reflections with and without ND is the same in the case of glare and the case of no glare.

[0194] Next, the relationship between the calibration light source and the object to be measured 1 will be examined.

[0195] When the calibration light source and the object 1 are of the same type, no absolute value error occurs with or without the ND filter 40. Therefore, no linear error (ND step) occurs when the ND filter is switched.

[0196] On the other hand, when the calibration light source and the object 1 are of different types, Figure 8 (A)(B) and Fig. 9 The results shown in (A) and (B) show that the absolute value error is -0.4% when there is no ND filter and the absolute value error is -0.4% when there is an ND filter, and no linear error (ND step) occurs.

[0197] Specifically,

[0198] (1) When using a glare-type light source for calibration

[0199] Without ND correction factor: Knon = incident light / received light = 100 / 90.45

[0200] With ND correction factor: Knd = incident light / received light = 100 / 4.52256

[0201] The measured value of the glare type object 1 after correction by the correction count is:

[0202] No-ND measurement value = light intensity × No-ND correction factor = 90.45 × 100 / 90.45 = 100 (absolute value error 0%)

[0203] ND measurement value = light intensity × ND correction factor = 4.52256 × 100 / 4.52256 = 100 (absolute value error 0%)

[0204] The difference in measured values ​​with and without ND (with ND - without ND) = 100 - 100 = 0 (linear error (ND step difference) 0%)

[0205] On the other hand, the measured values ​​of the non-glare type DUT 1 are:

[0206] No-ND measurement value = light intensity × No-ND correction factor = 90.09 × 100 / 90.45 = 99.602 (absolute value error - 0.4%)

[0207] ND measurement value = light intensity × ND correction factor = 4.50451 × 100 / 4.52256 = 99.601 (absolute value error - 0.4%)

[0208] The difference in measured values ​​with and without ND (with ND - without ND) = 99.601 - 99.602 = 0.001 (linear error (ND step difference) + 0%)

[0209] (2) When using a non-glare light source for calibration

[0210] In this case, the opposite situation to the case of correction using a glare type light source occurs, and in the measured value of the glare type object 1, an absolute value error of ND+0.4% and ND+0.4% occurs, but no linear error (ND step) occurs (0%).

[0211] (3) Relationship with the specifications of the light measuring device (accuracy required by the customer)

[0212] The absolute value error (without ND -0.4%, with ND -0.4%) generated in the above example is smaller than the specification (±2%), so it does not cause a problem. Also, the linear error (ND step difference) is 0%, so it does not cause a problem.

[0213] Thus, by providing a reflective member having the same return rate as the optical member 90 inside the photometric device 10 on the side of the measured object 1, it is possible to suppress a linear error (ND step) when switching between inserting and removing the dimming member 40.

[0214] Here, an example of a method for measuring the passing rate and the returning rate of the optical component 90 will be described.

[0215] For two photometric devices A and B, when the pass rate of the optical component 90 of the photometric device A is set to Top1 and the return rate of the optical component 90 is set to Rop1, and the pass rate of the optical component 90 of the photometric device B is set to Top2 and the return rate of the optical component 90 is set to Rop2,

[0216] The passing rate of the optical component 90 of the light measuring device A: Top1 = 1 - Rop1

[0217] Return rate of the optical component 90 of the photometric device A: Rop1.

[0218] (1) First, find the sensitivity ratio of the two photometric devices A and B: C, and calculate the ratio of the pass rates of photometric device A to photometric device B.

[0219] That is, Fig.10 As shown in (A), when light of intensity E is irradiated from light source K to photometric device A and photometric device B, the light intensity V10 received by photometric device A and the light intensity V20 received by photometric device B are:

[0220] V10=E×Top1

[0221] V20=E×Top2.

[0222] Furthermore, the sensitivity ratio C of the two photometric devices is:

[0223] C=V10 / V20=Top1 / Top2.

[0224] (2) Next, a measurement value is obtained using a half mirror whose transmittance and reflectance are known.

[0225] That is, Fig.10 As shown in (B), a half mirror H with transmittance Thm and reflectance Rhm is arranged between the light source K and the photometric device A. Then, the return light from the photometric device A is reflected by the half mirror H and the photometric device B performs photometry.

[0226] At this time, the light intensity V11 of the photometric device A and the light intensity V21 of the photometric device B are:

[0227] V11=E×Thm×Top1

[0228] V21=E×Thm×Rop1×Rhm×Top2.

[0229] In V21, (E×Thm×Rop1) is the return light from the photometric device A.

[0230] When E is calculated based on the above V11 and V21,

[0231] E=V11 / (Thm×Top1)=V21 / (Thm×Rop1×Rhm×Top2)

[0232] Therefore, when the return rate Rop1 of the optical component 90 of the photometric device A is calculated according to this formula,

[0233] Rop1=(V21 / V11)×(1 / Rhm)×(Top1 / Top2)=(V21 / V11)×(1 / Rhm)×C.

[0234] Then, the pass rate of the optical component 90 of the photometric device A is obtained by Top1=1-Rop1.

[0235] Next, the optimum value of the reflectance of the reflecting member on the surface of the light reduction member 40 is obtained.

[0236] Assume that the incident light is E, the reflectivity of the object 1 to be measured is RDUT, the transmittance and return rate of the optical component 90 are Top and Rop respectively, and the transmittance and reflectivity of the dimming component 40 are Tnd and Rnd respectively.

[0237] In a state where the attenuation component 40 is not inserted into the optical path,

[0238] Light Received 1 = E × Top

[0239] Amount of received light 2 = E × Rop × RDUT × Top.

[0240] On the other hand, in a state where the attenuation member 40 is inserted into the optical path,

[0241] Received light 1 = E × Tnd × Top

[0242] Received light amount 2 = E × Tnd × Rop × Tnd × RDUT × Tnd × Top

[0243] Amount of received light 3 = E×Rnd×RDUT×Tnd×Top.

[0244] Here, when the ratio of the amount of light received = the amount of light received with ND ÷ the amount of light received without ND = the ND transmittance ... formula [1] is satisfied, the linear error (ND step difference) is 0.

[0245] When the sum of the light received with and without ND and the ND transmittance Tnd are inserted into the formula [1] and transformed,

[0246] {(E×Top)+(E×Rop×RDUT×Top)}×Tnd

[0247] =(E×Tnd×Top)+(E×Tnd×Rop×Tnd×RDUT×Tnd×Top)+(E×Rnd×RDUT×Tnd×Top).

[0248] When solving this equation for the reflectivity Rnd of the dimming component 40,

[0249] Rnd=Rop(1-Tnd^2)...Formula [2].

[0250] When the linear error (ND step difference) is allowed to be ±Eerr%, the allowable width of the reflectivity Rnd of the light reduction member 40 is given by ⊿Rnd0=Eerr / RDUT.

[0251] Here, when the linear error is less than ±0.2% and the reflectivity of the main smartphone is less than 5%, under this condition, the allowable range of the reflectivity (Rnd) of the dimming component 40 is:

[0252] ⊿Rnd0=Eerr / RDUT=0.002 / 0.05=0.04.

[0253] As mentioned above, the reflectivity of the preferred dimming component 40, that is, the reflectivity of the reflecting component, is:

[0254] The optimal reflectivity (Rnd0) ±4% = Rop×(1-Tnd^2) ±4%.

[0255] If a specific example of calculating the reflectivity is given, for example, the condition setting of the photometric device 10 is

[0256] Internal optical component 90 return rate Rop = 10%

[0257] When the transmittance Tnd of the light attenuating component 40 is 5%,

[0258] The optimal reflectivity of the dimming component (reflecting component) is: Rnd0 = Rop × (1-Tnd^2) = 0.1 × (1-0.05^2) = 9.4%

[0259] In order to achieve a linear error (ND step) of 0.2% or less in a major smartphone (reflectivity 5% or less), the reflectivity of the dimming component (reflection component) may be set to reflectivity = 5.4% to 13.4%.

[0260] When the dimming component 40 is a thin film filter, the reflecting component may also be composed of a thin film integrally formed on its surface. In particular, the reflectivity can be controlled by the thin film on the front surface side, i.e., the side of the measured object 1. Since the film structure also affects the transmittance, a film structure suitable for both transmission and reflection is required.

[0261] Furthermore, the reflective member may be formed by the surface of a glass absorption filter, or another reflective member may be formed integrally with the light reduction member 40 .

[0262] Alternatively, the reflecting member may be formed of another component separate from the light reduction member 40, and may be disposed in a state separated from the light reduction member 40. An embodiment in which the reflecting member is formed of another component separate from the light reduction member 40 will be described below.

[0263] Fig.11 (A) shows the transmittance of the ND filter 40 composed of a thin film filter whose thin film is a niobium oxide film in the visible light region (380 to 780 nm). The average transmittance is 5%.

[0264] Fig.11 (B) shows the reflectance in the visible light region of the ND filter 40 composed of three thin film filters, namely, niobium oxide film 1, niobium oxide film 2, and niobium oxide film 3. The average reflectance is 10% for the thin film filter of niobium oxide film 1, and 5% for each of the thin film filters of niobium oxide films 2 and 3.

[0265] By combining such niobium oxide films to form a multilayer film, the reflectivity can be controlled.

[0266] Fig.12(A), (B), and (C) respectively represent the transmittance in the visible light region of the ND filter 40 composed of a glass absorption filter, the reflectance in a state where a single-layer anti-reflection film is formed, and the reflectance when there is no anti-reflection film but only a protective film. The average transmittance in the case of (A) is 5%, the average reflectance in the case of (B) is 1.5%, and the average reflectance in the case of (C) is 4.5%.

[0267] As described above, according to this embodiment, the occurrence of a linear error (ND step) whose magnitude varies due to characteristics such as the surface reflectance of the object to be measured 1 can be prevented by the reflective member formed integrally with the ND filter 40 or by the reflective member formed of a component different from the ND filter 40. In other words, regardless of the characteristics of the object to be measured 1, the difference in measurement values ​​caused by the linear error (ND step), that is, the difference between the measurement value in the state where the ND filter 40 is not inserted in the optical path of the light to be measured and the measurement value in the state where the ND filter 40 is inserted in the optical path of the light to be measured, can be corrected by the reflective member.

[0268] [Modification 1]

[0269] This deformation, for example Fig.13 As shown, an optical fiber bundle 30 is used instead of the diffuser 20 as the branching optical system 12 in the first embodiment, and the aperture stop 11b is not provided. It should be noted that the aperture stop 11b may also be provided. In addition, condensing lenses 19a to 19c are arranged between the emission end of the optical fiber bundle 30 and each color filter.

[0270] ND filter 40, plug-in device 50, color filters 13a, 14a, 15a, light receiving sensors 13b, 14b, 15b, electrical processing units 16a to 16c, control unit 17 and other components and Figure 1 Implementation 1 is substantially the same as that of the present invention, so the same reference numerals are given and the description thereof is omitted. Fig.13 In the embodiment, the electrical processing units 16a, 16b, 16c and the control unit 17 are omitted.

[0271] The optical fiber bundle 30 is a bundle of n (n = hundreds to thousands) bare optical fibers with small diameters (φ = about 0.03 to 0.3 mm) at the entrance side, and randomly branched into multiple fibers (in this embodiment, three corresponding to the three stimulus values ​​X, Y, and Z) at the exit side, and each multiple m fibers are bundled. Reference numerals 31, 32, and 33 are branching parts. The shapes of the incident end 30a and the exit ends 31a, 32a, and 33a of each branch part 31, 32, and 33 are arbitrary (circular, rectangular, etc.).

[0272] exist Fig.13In the photometric device 10, a part of the measured light 2 from the measured object 1 that has passed through the objective optical system 11 returns to the measured object 1 side through the reflecting component of the ND filter 40. By adjusting the reflectivity of the reflecting component of the ND filter 40, the occurrence of linear error (ND step) can be prevented.

[0273] and, Fig.13 The light measuring device 10 shown is Figure 1 The objective optical system 11 is configured to be front-telecentric similarly to the photometric device 10 of the illustrated embodiment 1. In the case of front-telecentricity, most of the reflected light reflected from the surface of the object 1 to be measured returns to the photometric device 10.

[0274] That is, in the case of anterior telecentricity, Fig.14 As shown in S1 to S3 of (A), the light returning to the side of the object 1 at 0 degrees is reflected by the surface of the object 1 and returns to the photometric device 10 at 0 degrees. The light returning to the side of the object 1 at +2.5 degrees is reflected by the object and returns to the photometric device 10 at -2.5 degrees. That is, due to the front telecentricity, all the angular components of the light return to the photometric device 10. It should be noted that Fig.14 The light attenuation component 40 and the plug-in device 50 are omitted.

[0275] On the other hand, in the case of an optical system that is not a front telecentric system such as a normal camera lens, Fig.14 As shown in (B), the light rays around the measurement area have an angle and therefore do not return to the photometric device 10 .

[0276] [Modification 2]

[0277] This modification example includes a finder optical system for a measurer to recognize the periphery of a measured area.

[0278] That is, Fig.15 As shown, a reflector M that bends a portion of the optical path is disposed between the objective optical system 11 and the incident end 30a of the branch optical system 12 (optical fiber bundle 30). Furthermore, the light beam that is not reflected by the reflector M is directed to the branch optical system 12 and the light receiving sensors 13b, 14b, and 15b to measure brightness, chromaticity, etc. On the other hand, the light beam reflected by the reflector M is directed to the viewfinder optical system 60, so that the measurer can identify the periphery of the measured area. Fig.15 In the figure, reference numerals S1 and S2 are slits.

[0279] When the ND filter 40 is arranged in front of the reflector M, the ND filter 40 is inserted and removed due to the brightness of the object 1, and thus is difficult to recognize. Therefore, the ND filter 40 may be arranged behind the reflector M.

[0280] Except that the objective optical system 11 is not front telecentric and includes a viewfinder optical system 60, reflecting mirrors M, S1 and S2, the present invention is substantially the same as the first modification, and thus the description thereof is omitted. Fig.15 In the embodiment of the present invention, the condenser lenses 19a, 19b, and 19c behind the optical fiber bundle 30 are omitted. In addition, the diffuser plate 20 may be used instead of the optical fiber bundle 30.

[0281] [Variation 3]

[0282] In this variation, if Fig.16 As shown, in Figure 1 In the photometric device 10 of the first embodiment shown, the convex lens 11 a and the aperture stop 11 b as the objective optical system 11 are omitted. Therefore, the measured light 2 from the measured object 1 directly enters the ND filter 40 .

[0283] The structure is the same as that of the optical system 11 except that the objective lens optical system 11 is not present. Figure 1 The embodiment 1 shown is substantially the same, so the description thereof is omitted. It should be noted that the optical fiber bundle 30 may be used instead of the diffuser plate 20 .

[0284] [Variation 4]

[0285] In this modification, Figure 1 In the photometric device 10 of the first embodiment, the structure of the colorimetric optical system 13 is changed.

[0286] That is, Fig.17 As shown, a linear gradient filter (LVF) 70 that can continuously change the wavelength as a spectral filter is used instead of the three color filters 13a, 14a, and 15a. In addition, a line sensor 80 is used as a light receiving sensor. However, instead of the line sensor 80, a plurality of light receiving sensors may be used together.

[0287] The structure other than the color measurement optical system 13, 14, 15 Figure 1 The first embodiment shown is substantially the same, and therefore description thereof will be omitted.

[0288] It should be noted that the optical fiber bundle 30 may be used instead of the diffuser plate 20 .

[0289] [Variation 5]

[0290] In this modification, if Fig.18 As shown, the reflecting member 45 which is a separate component from the ND filter 40 is arranged in front of the ND filter 40 (on the side of the object 1 ). The ND filter 40 and the reflecting member 45 are simultaneously inserted and removed from the optical path of the light 2 to be measured by a common insertion and removal device 51 .

[0291] As the reflection member 45 , transparent glass can be cited, for example. Fig.19 (A), (B), and (C) respectively represent the transmittance of transparent glass in the visible light region, the reflectance in a state where a single-layer anti-reflection film is formed, and the reflectance in a state where there is no anti-reflection film but only a protective film. The average transmittance in the case of (A) is 95%, the average reflectance in the case of (B) is 1.5%, and the average reflectance in the case of (C) is 4.5%. The ND filter 40 can be a thin film filter with a low reflectance.

[0292] It should be noted that the structures other than the ND filter 40, the reflective component 45 and the plug-in device 51 are the same as those of the ND filter 40. Figure 1 The embodiment 1 shown is substantially the same.

[0293] [Variation 6]

[0294] In this modification, if Fig. 20 As shown, the reflecting component 45 which is a different component from the ND filter 40 is arranged in front of the light attenuating component 40 (on the side of the measured object 1), and the ND filter 40 and the reflecting component 45 are synchronously inserted and removed in the optical path of the measured light 2 by different insertion and removal devices 52 and 53.

[0295] It should be noted that the structures other than the ND filter 40, the reflective component 45 and the plug-in and pull-out devices 52 and 53 are the same as those of the ND filter 40 and the reflective component 45. Fig.13 The modified example 1 shown is substantially the same.

[0296] [ND filter insertion and removal control]

[0297] Fig.21 This is a flowchart for explaining a method of controlling the insertion and removal of the ND filter 40 by the photometric device 10 according to Embodiment 1. This control is performed by the control unit 17 .

[0298] After the measurement starts, the light receiving data V is acquired in step S01. X 、V Y 、V Z Next, in step S02, it is determined whether the ND filter 40 is inserted into the optical path (on) or retracted from the optical path (off).

[0299] In the case of retreat (off in step S02), in step S03, it is checked whether the light receiving data is less than the threshold value A. If it is smaller (YES in step S03), after referring to the correction coefficient knon in step S04, the stimulus values ​​X, Y, Z, luminance LV, chromaticity x, y are calculated in step S05 and output in step S07.

[0300] If the light receiving data is not less than the threshold value A in step S03 (NO in step S03), the ND filter 40 is inserted into the optical path in step S06, and the process returns to step S01 to acquire the light receiving data again.

[0301] If the ND filter 40 is inserted into the optical path in step S02 (on in step S02), then in step S08, it is checked whether the light receiving data is greater than the threshold value B. If it is greater (YES in step S08), after referring to the correction coefficient knd in step S09, the stimulus values ​​X, Y, Z, luminance LV, chromaticity x, y are calculated in step S10 and output in step S07.

[0302] If the light receiving data is not greater than the threshold value B in step S08 (NO in step S08), the ND filter 40 is retracted from the optical path in step S11, and the process returns to step S01 to acquire the light receiving data again.

[0303] [Implementation Method 2]

[0304] In the first embodiment (including various modified examples) described above, a linear error (ND step) between a measured value when the ND filter 40 is not inserted in the optical path of the measured light 2 and a measured value when the ND filter 40 is inserted in the optical path of the measured light 2, which is generated when the reflectivity of the measured object 1 is different, is corrected by using a reflecting component. As a result, an appropriate measurement value can be obtained without being restricted by differences in the characteristics of the measured object 1.

[0305] In this second embodiment, the linear error (ND step difference) is corrected by calculation using a correction coefficient (equivalent to a correction coefficient).

[0306] Fig. 22 2 shows the overall configuration of the calibration system. The calibration system includes a photometric device 10, an information processing device 300 such as a personal computer, and an object to be measured 1.

[0307] The photometric device 10 has a cylindrical lens barrel 10 a on the front end side for taking in the measured light 2 from the measured object 1 , and has a communication unit 10 b on the back side for communicating measurement data, control signals, etc. with the information processing device 300 .

[0308] In this embodiment, the internal structure of the photometric device 10 is as follows: Figure 1 Although the light measuring device 10 of the embodiment 1 shown in the figure can also be used Fig.13 , Figure 15 to Figure 18 as well as Fig. 20 Any of the photometric devices 10 of the modified examples 1 to 6 shown.

[0309] The internal structure of the photometric device 10 is the same as that of the first embodiment, but the reflectivity of the ND filter 40 is not limited, and a thin film filter, a glass absorption filter, etc., which are generally used as ND filters, can be used. The ND filter 40 is inserted and removed from the optical path of the measured light 2 according to the brightness of the measured object 1, as in the first embodiment. Specifically, the ND filter 40 is inserted into the optical path when the light amount of the measured light 2 is greater than a predetermined light amount.

[0310] Fig.23 Detailed configuration of the control unit 17 is shown. The control unit 17 includes a CPU 171, a ROM 172, a RAM 173, a storage unit 174, and the like.

[0311] The CPU 171 operates according to the operation program to centrally control the entire photometric device 10. For example, when measuring the object 1, the CPU 171 receives signals from the electrical processing units 16a to 16c, performs corrections as necessary, and calculates the measured value. In addition, in this embodiment, when the user calibration is performed based on the instruction of the user of the photometric device 10, the CPU 171 performs processing such as calculation of the correction coefficient, which will be described in detail later.

[0312] The ROM 172 is a memory for storing an operation program or other data. The RAM 173 is a memory for providing a work area for the CPU 171 when operating according to the operation program. In addition, the RAM 173 stores measurement values ​​such as brightness and chromaticity as calculation results.

[0313] The storage unit 174 is composed of a storage medium such as a flash ROM or FeRAM, and stores various data such as correction coefficients obtained when the photometric device 10 is factory calibrated before shipment, correction coefficients obtained by user calibration, and predetermined setting values.

[0314] Next, the calculation for obtaining the measurement values ​​(tristimulus values) performed by the control unit 17 will be described.

[0315] Generally, when calculating the tristimulus values ​​(X, Y, Z) based on the light receiving data (count values) obtained from the outputs of the light receiving sensors 13b, 14b, and 15b, the control unit 17 performs the following operations: Fig.24 The calculations are as shown in the flowcharts of (A) and (B). The individual deviations are caused by the deviation of the internal reflectivity of the light measuring device 10, the change of the light amount caused by the insertion and removal of the ND filter 40, and the deviation of the reflectivity of the ND filter 40. Fig.24 The value is corrected by calculation as in the flowcharts of (A) and (B).

[0316] Fig.24(A) is a calculation process when the ND filter 40 is not inserted into the optical path. In step S21, the ND conversion factory correction coefficient N (no ND) is multiplied by the count value, and in step S22, it is further multiplied by the factory correction coefficient M to obtain the tristimulus value.

[0317] FIG. 4B shows the calculation process when the ND filter 40 is inserted into the optical path. In step S31, the ND conversion factory correction coefficient N (with ND) is multiplied by the count value, and in step S32, it is further multiplied by the factory correction coefficient M to obtain the tristimulus values.

[0318] The “ND conversion factory correction coefficient N (with ND)” in step S31 is a correction coefficient for correcting the difference between the presence and absence of the ND filter 40 caused by the difference between the reflectivity of the ND filter 40 and the internal reflectivity of the photometric device 10 .

[0319] Specifically, it is a correction coefficient for making correction using a reference light source so that the measurement data in the state where the ND filter 40 is inserted into the optical path and the state where it is not inserted into the optical path are consistent. When the light amount of the measured light 2 is less than the specified light amount, the ND filter 40 is not inserted into the optical path, so such correction is not required. Therefore, the "ND conversion factory correction coefficient N (no ND)" in step S21 in the figure (A) is a unit matrix.

[0320] It should be noted that the factory correction coefficient M is a correction coefficient when the product is calibrated using a reference light source at the factory before shipment so that the output of the photometric device 10 is consistent with the output (reference value) when the reference light source is measured by the reference device. The ND conversion factory correction coefficient N (with ND), the ND conversion factory correction coefficient N (without ND), and the factory correction coefficient M are written into the storage unit of the photometric device 10, etc.

[0321] By calculating the tristimulus values ​​using the factory calibration coefficients M, predetermined values ​​can be obtained when measuring the object 1 having the same surface reflectance as that of the light source used in the factory calibration.

[0322] Next, consider a case where a customer's object 1 having a surface reflectance different from that of a reference light source is measured.

[0323] Even when the photometric device 10 that performs matrix correction is used as described above, if the objects 1 of customers with different surface reflectances are measured, the tristimulus values ​​will deviate from the prescribed values ​​due to the difference between the correction light source and the surface reflectance of the object 1.

[0324] Therefore, many photometric devices have a user correction function. This user correction function is a function of obtaining a user correction coefficient U using a main panel having representative characteristics of the measured object 1. Specifically, the output value (reference value) when the main panel is measured by a reference device such as a spectrophotometer is compared with the output value when the main panel is measured using the photometric device 10 for measurement without inserting the ND filter 40, and the user correction coefficient U is obtained so that the two output values ​​are consistent.

[0325] After the user correction coefficient U is obtained, the tristimulus values ​​are calculated using the user correction coefficient U. Fig.24 After the factory correction coefficient M shown in the flowcharts of (A) and (B) is corrected, it is multiplied by the user correction coefficient U for correction.

[0326] By this correction processing, the prescribed value can be obtained when the ND filter 40 is not inserted in the optical path. However, if the reflectance of the surface of the ND filter 40 on the side of the object 1 to be measured is different from the internal reflectance of the photometric device 10 (reflection of the color filters 13a, 14a, 15a and the light receiving sensors 13b, 14b, 15b) by only user correction, the reflectance has different effects, and a linear error (ND step difference) when the ND filter is inserted or removed occurs in the glare type object 1 to be measured and the non-glare type object to be measured. This is as described in the item <Problems that occur when the dimming component 40 is inserted or removed> in the first embodiment.

[0327] Therefore, in this second embodiment, in order to eliminate the above-mentioned linear error (ND step difference), a correction process based on ND conversion user correction described below is performed.

[0328] This ND conversion user correction coefficient is calculated, similar to the user correction, by measuring using a main panel that is different from the reference light source and has representative characteristics of the object to be measured 1. The calculation process will be described below.

[0329] First, the main panel 1 is illuminated without the ND filter 40 inserted into the optical path, and the outputs (count values ​​C) from the light receiving sensors 13b, 14b, and 15b at this time are stored. At this time, if the luminance (brightness) of the main panel 1 is too high, the light receiving sensors will be saturated, and appropriate ND conversion user correction cannot be performed. Therefore, the count value C for performing ND conversion user correction is limited to a specified range.

[0330] Next, based on the stored count value, the tristimulus values ​​S in the state where the ND filter 40 is not inserted are calculated using the ND conversion factory correction coefficient N (no ND) and the factory correction coefficient M. Un2(W，R，G，B) . The formula is as follows.

[0331] SUn2(W，R，G，B) =M·N(without ND)·C

[0332]

[0333] Next, the main panel 1 is illuminated with the ND filter 40 inserted in the optical path, and the outputs (count values ​​C) from the light receiving sensors 13b, 14b, and 15b at this time are stored. At this time, if the luminance (brightness) of the main panel 1 is too low, the stability of the light emission of the main panel 1 is impaired, and appropriate ND conversion user correction cannot be performed. Therefore, the count value C for performing the ND conversion user correction is limited to a predetermined range.

[0334] It should be noted that the exposure time in the state where the ND filter 40 is inserted into the optical path is longer than the exposure time in the state where the ND filter 40 is not inserted into the optical path. The reason for this is that when the ND filter 40 is inserted, the light becomes darker, so the exposure time is extended to obtain the S / N compared to the state where the ND filter 40 is not inserted. At this time, the exposure time in the state where the ND filter 40 is inserted can be set to the exposure time where the S / N becomes the same as the exposure time when the ND filter 40 is not inserted.

[0335] Based on the stored count value, the tristimulus value S in the state where the ND is inserted is calculated using the ND conversion factory correction coefficient N (with ND) and the factory correction coefficient M. Un1(W，R，G，B) . It can be expressed as follows.

[0336] S Un1(W，R，G，B) =M·N(with ND)·C

[0337]

[0338] Then, according to the tristimulus value S Un1(W，R，G，B) and tristimulus value S Un2(W，R，G，B) The ND conversion user correction coefficient Un is calculated, and the calculated ND conversion user correction coefficient Un is stored as a first correction coefficient in the storage unit 174. The calculation of the ND conversion user correction coefficient Un is performed as follows:

[0339] Calculate S by matrix correction operation Un2(W，R，G，B) ≒Un·S Un1(W，R，G，B) Un.

[0340] It should be noted that the calculation itself for obtaining the matrix correction coefficient can be performed using a well-known method, and the outline is as follows.

[0341] If the conversion source RGB is set to a 3×3 matrix: A1, the conversion target RGB is set to a 3×3 matrix: A2

[0342] Then A2=Un RGB ×A1,UnRGB =A2×A1 －1 , therefore, in finding the inverse matrix A1 －1 After that, according to Un RGB =A2×A1 －1 Find Un RGB .

[0343] It should be noted that the measurement for the ND conversion user calibration is performed by causing the object to be measured 1 to emit W (white), R (red), G (green), and B (blue).

[0344] In this case, the exposure sequence is as follows:

[0345] a) The emission color of the object 1 to be measured is fixed, and the ND filter is switched between without ND filter (non-insertion) and with ND filter (insertion). For example, white, without ND filter → white, with ND filter → red, without ND filter → red, with ND filter → green, without ND filter → green, with ND filter → blue, without ND filter → blue, with ND filter.

[0346] b) Fix the ND filter and the ND filter, and switch the light color. For example, no ND filter, white → no ND filter, red → no ND filter, green → no ND filter, blue → with ND filter, white → with ND filter, red → with ND filter, green → with ND filter, blue.

[0347] Any order of a) and b) may be used, but in view of the stability of the light emission of the object 1 to be measured, the order of a) with less switching of light emission is preferred in terms of improving the calibration accuracy.

[0348] The light emission control of the object 1 is performed by the information processing device 300. The object 1 emits light in a predetermined order based on the light emission instruction from the information processing device 300. In addition, the information processing device 300 communicates with the photometric device 100, and the photometric device 100 switches the insertion and removal of the ND filter based on the signal from the information processing device 300.

[0349] Furthermore, in order to perform high-precision correction in the shortest possible time, it is preferable to increase the luminance (brightness) in a state where the ND filter is present.

[0350] However, if the luminance (brightness) is increased with the ND filter, the luminance (brightness) without the ND filter becomes too high, and the light receiving sensors 13b, 14b, and 15b are saturated, making it impossible to perform appropriate ND conversion user correction.

[0351] To cope with this, when the photometric device 10 detects saturation of the light receiving sensors 13b, 14b, and 15b, the detection signal is sent to the information processing device 300, and the information processing device 300 performs control to reduce the luminance (brightness) of the object 1 to be measured to a non-saturated luminance (brightness).

[0352] It should be noted that the calculation of the ND conversion user correction coefficient Un is performed by the photometric device 10 .

[0353] exist Fig.25 The flowchart of FIG. 1 shows a calculation process when tristimulus value calculation is performed using the ND conversion user correction coefficient Un obtained by the ND conversion user correction function.

[0354] exist Fig.25 In the flowchart of FIG. 1 , the ND conversion factory correction coefficient N (with ND) is multiplied by the count value C in step S41, and further multiplied by the ND conversion user correction coefficient Un in step S42. In step S43, after further multiplying by the factory correction coefficient M, it is multiplied by the user correction coefficient U in step S44 to obtain the tristimulus values.

[0355] As described above, the user correction coefficient U is calculated based on the output of the main panel having representative characteristics of the object 1 to be measured (reflectivity in this embodiment) measured by the reference device, and the output value of the main panel measured by the photometric device 10 in a state where the ND filter 40 is not inserted into the optical path, and the second correction coefficient used to make the two consistent is calculated by the photometric device 10.

[0356] In this way, by using the ND conversion user correction coefficient Un to correct the count values ​​from the light receiving sensors 13b, 14b, and 15b, even if an ND filter 40 is used in which the reflectivity of the surface and the internal reflectivity (return rate) of the ND filter 40 are different, a specified appropriate value can be obtained in the panel measurement of customers with different surface reflectivities, such as glare type and non-glare type.

[0357] It should be noted that the action of obtaining the ND conversion user correction coefficient Un and the action of obtaining the user correction coefficient U are performed continuously because they are less susceptible to the influence of time changes, so it is preferred. In addition, since the ND conversion user correction is limited to the range of luminance (brightness) that can be properly corrected, if the ND conversion user correction is performed after the user correction, the ND conversion user correction cannot be properly implemented, and thus the user correction previously performed may be wasted. Therefore, in the case of performing the action of obtaining the ND conversion user correction coefficient Un and the action of obtaining the user correction coefficient U continuously, it is preferred to perform the ND conversion user correction first.

[0358] However, depending on the situation, there may be a case where only ND conversion and user correction Un can obtain a predetermined value, or only user correction U can obtain a predetermined value, and therefore, each operation may be performed separately.

[0359] In this embodiment, the information processing device 300 has a processing mode for calculating only the ND conversion user correction coefficient Un, a processing mode for calculating only the user correction coefficient U, and a processing mode for continuously calculating both coefficients. Fig.26 As shown in FIG. 1 , a mode selection screen is displayed on the information processing device 300 , and the user can select any mode by checking a check box or the like.

[0360] Furthermore, the ND conversion user correction coefficients UnA, UnB, etc. or the user correction coefficients UA, UB, etc. may be calculated for each object 1 having different surface reflection characteristics, as shown in FIG. Fig. 27 As shown, the obtained ND conversion user correction coefficients UnA, UnB, etc., or further the user correction coefficients UA, UB, etc. are stored in the storage unit 174 in association with the type of the object 1. The ND conversion user correction coefficient Un, etc. used may be selected according to the type of the object 1 to be measured.

[0361] As mentioned above, although Embodiment 2 of the present invention has been described, the present invention is not limited to the above-mentioned Embodiment 2.

[0362] For example, the light-emitting state of the object 1 to be measured is controlled by the information processing device 300, but the light-measuring device 10 may have a control function for controlling the light-emitting state of the object 1 to be measured, and the ND conversion user correction and user correction may be performed by the object 1 to be measured and the light-measuring device 10. Furthermore, the light-measuring device 10 calculates the ND conversion user correction coefficient Un and the user correction coefficient U, but the information processing device 300 may calculate and write them into the storage unit 174 of the light-measuring device 10.

[0363] Industrial Applicability

[0364] The present invention can be used as a photometric device capable of measuring the brightness, chromaticity, etc. of light emitted from a measurement object such as a display of a smartphone or a liquid crystal monitor.

[0365] Description of Reference Numerals

[0366] 1: Object to be measured;

[0367] 2: measured light;

[0368] 10: Light measuring device;

[0369] 10a: lens barrel;

[0370] 10b: Communications Department;

[0371] 11: Objective optical system;

[0372] 11a: convex lens;

[0373] 11b: aperture stop;

[0374] 12: Branch optical system;

[0375] 13-15: Color measurement optical system;

[0376] 13a, 14a, 15a: wavelength selective filters;

[0377] 13b, 14b, 15b: light receiving sensors;

[0378] 16, 16a~16c: electrical processing unit;

[0379] 20: diffuser plate;

[0380] 30: optical fiber bundle;

[0381] 30a: incident end;

[0382] 31-33: branch part;

[0383] 31a~33a: emission end;

[0384] 40: light attenuation component;

[0385] 41: Transparent plate;

[0386] 41a: incident surface;

[0387] 41b: exit surface;

[0388] 42, 43: film;

[0389] 45: reflective component;

[0390] 50: plug-in device;

[0391] 60: Viewfinder optical system;

[0392] 300: Information processing device.

Claims

1. A light measuring device, characterized in that: have: a light receiving unit having one or more light receiving sensors for receiving light to be measured from the object to be measured; a control unit that calculates a measurement value based on an output from the light receiving sensor; a light attenuation component which is pluggable and disposed in the optical path of the light to be measured and which attenuates the light incident on the light receiving part; The correction unit corrects the difference between the measurement value calculated by the control unit in the state where the light attenuation component is inserted into the optical path and the measurement value calculated by the control unit in the state where the light attenuation component is not inserted into the optical path, which varies according to the characteristics of the object to be measured.

2. The light measuring device according to claim 1, The correction unit is a reflection member that is inserted into the optical path when the light attenuation member is inserted into the optical path, and is retracted from the optical path when the light attenuation member is retracted from the optical path.

3. The light measuring device according to claim 2, The reflective component is formed integrally with the light attenuating component.

4. The light measuring device according to claim 2, The reflecting component is a component different from the light attenuating component and is composed of one or more components.

5. The light measuring device according to any one of claims 1 to 4, The reflectivity of the reflective component is an optimum reflectivity of ±4%.

6. The light measuring device according to claim 1, The correction unit is composed of a control unit that calculates a measurement value using a correction coefficient corresponding to the physical property of the measurement object.

7. The light measuring device according to claim 6, A storage unit for storing the correction coefficient is provided.

8. The light measuring device according to claim 6 or 7, The control unit obtains, based on a user instruction, an output value output from the light receiving unit when the light attenuation member is inserted into the optical path and an output value output from the light receiving unit when the light attenuation member is not inserted into the optical path, and obtains the correction coefficient based on these output values.

9. The light measuring device according to claim 8, An exposure time for obtaining an output value output from the light receiving section in a state where the light attenuating member is inserted is longer than an exposure time for obtaining an output value output from the light receiving section in a state where the light attenuating member is not inserted.

10. The light measuring device according to claim 8, The correction coefficient is obtained when an output value output from the light receiving unit in a state where the light attenuation member is inserted in the optical path and an output value output from the light receiving unit in a state where the light attenuation member is not inserted in the optical path are within a predetermined range.

11. The light measuring device according to claim 7, The storage unit stores a plurality of correction coefficients corresponding to the plurality of objects to be measured, respectively.

12. The light measuring device according to claim 6 or 7, The characteristic of the object to be measured is the reflectivity of the object to be measured.

13. A calibration system for calibrating the light measuring device according to claim 8, characterized in that: The correction system includes an information processing device, and when the correction coefficient according to claim 8 is set as a first correction coefficient, the information processing device requests the control unit to obtain the first correction coefficient based on a user's instruction, and A request is made to further obtain a second correction coefficient based on a reference value of the object to be measured and an output value when the light receiving unit receives light from the object to be measured in a state where the light attenuation member is not inserted into the optical path.

14. The correction system according to claim 13, After requesting to find the first correction coefficient, requesting to find the second correction coefficient.

15. A calibration system for calibrating the light measuring device according to claim 8, characterized in that: The correction system includes an information processing device, and when the correction coefficient according to claim 8 is set as a first correction coefficient, the information processing device performs a process different from requesting the control unit to obtain the first correction coefficient based on a user's instruction. There is a mode for requesting processing to obtain the second correction coefficient based on a reference value of the object to be measured and an output value when the light receiving unit receives light from the object to be measured in a state where the light attenuation member is not inserted into the optical path.

16. A calibration system for calibrating the light measuring device according to claim 8, characterized in that: The calibration system includes an information processing device, and when the correction coefficient described in claim 8 is set as a first correction coefficient, the information processing device performs processing different from requesting the control unit to obtain a second correction coefficient based on a reference value of the object to be measured and an output value when the light receiving unit receives light from the object to be measured in a state where the light attenuation component is not inserted into the optical path, based on an instruction from a user, There is a mode for requesting only the process of finding the first correction coefficient.

17. A light measuring device according to any one of claims 1, 2, 6 or 7, The light attenuating component is inserted and removed according to the brightness of the object to be measured.

18. A light measuring device according to any one of claims 1, 2, 6 or 7, The light receiving sensor is a silicon sensor.

19. A light measuring device according to any one of claims 1, 2, 6 or 7, A wavelength selection filter is provided in front of the light receiving sensor.

20. A light measuring device according to any one of claims 1, 2, 6 or 7, The wavelength selective filter is a thin film filter.

21. A light measuring device according to any one of claims 1, 2, 6 or 7, The light attenuating component is composed of a thin film filter.

22. A light measuring device according to any one of claims 1, 2, 6 or 7, A branching optical system is provided for branching the light to be measured into a plurality of light beams.

23. A light measuring device according to any one of claims 1, 2, 6 or 7, The measurement wavelength range of the light to be measured is the visible light region.

24. A light measuring device according to any one of claims 1, 2, 6 or 7, The wavelength selective filter is a color-selective filter.

25. A light measuring device according to any one of claims 1, 2, 6 or 7, The wavelength selection filter is a spectral filter, and the light receiving sensor is a line sensor.

26. A light measuring method of a light measuring device, characterized in that: The light measuring device has: a light receiving unit having one or more light receiving sensors for receiving light to be measured from the object to be measured; a control unit that calculates a measurement value based on an output from the light receiving sensor, A light attenuation component is inserted or removed from an optical path of the light to be measured in the photometric device, and a difference between a measurement value calculated by the control unit in a state where the light attenuation component is inserted into the optical path and a measurement value calculated by the control unit in a state where the light attenuation component is not inserted into the optical path, which varies according to characteristics of the object to be measured, is corrected.

27. A calibration system for calibrating the light measuring device according to claim 8 for each display color used as a reference, characterized in that: The correction coefficient is obtained by switching the insertion and removal of the light attenuating member while the reference display color is fixed.

28. A calibration system for calibrating the light measuring device according to claim 8, characterized in that: When saturation of the light receiving sensor in the light measuring device is detected during the process of obtaining the correction coefficient, the brightness of the object to be measured is reduced.

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