Photometry device and method for inspecting display

Abstract

Provided are: a photometry device in which the interval between a plurality of measurement regions can be narrowed and the accuracy of measurement is improved; and a method for inspecting a display using the photometry device.　This photometry device comprises an objective optical system that condenses light from each of a plurality of prescribed regions and forms an image. The photometry device comprises a plurality of light guide members that have, for each of the prescribed regions, an incident port at an image formation location of the objective optical system and that guide, by internal reflection, the light of the image formed for each of the prescribed regions. The photometry device comprises a light receiving unit that receives light emitted from emission ports in the plurality of light guide members.

Description

Light Measuring Device and Inspection Method for Display

[0001] The present disclosure relates to a light measuring device and an inspection method for a display.

[0002] A light measuring device for measuring light from a light emitter is known. For example, a color luminance meter, which is one type of light measuring device, can measure the optical characteristics of a display, and based on the measurement results, the color of the display can be adjusted.

[0003] When the display is small, the measurement area for measuring the optical characteristics also becomes small. Generally, in the object to be measured, the amount of light emitted from the measurement area decreases as the area of the measurement area becomes smaller. Therefore, a light measuring device that measures the optical characteristics by incorporating a larger amount of light from a small measurement area is known (Patent Documents 1 to 3).

[0004] International Publication No. 2011 / 121896, International Publication No. 2018 / 230177, Japanese Patent Application Laid-Open No. 2003-247891

[0005] In recent years, in the field of displays, a technology called Under Panel Solution (UPS) has been developed. UPS is a technology in which a camera module, a face recognition module, etc. are arranged on the back of a display, and a device adopting UPS has a configuration in which it is difficult to visually recognize modules such as a camera through the display. In such a device, the part of the display that overlaps with the module (UPS part) and the part of the display that does not overlap with the module (non-UPS part) have different structures. For example, in the γ adjustment of a display, γ adjustment is required for each of the UPS part and the non-UPS part.

[0006] In order to shorten the tact time in γ adjustment, it is necessary to simultaneously measure the luminance of each of the UPS part and the non-UPS part. Also, from the viewpoint of reducing the influence of the in-plane light emission distribution in the display, it is preferable that the measurement areas of the UPS part and the non-UPS part are close to each other.

[0007] However, in the technologies described in Cited Documents 1 to 3, if the intervals between such a plurality of measurement areas are made extremely narrow and measured simultaneously, the light emitted from the plurality of measurement areas interferes with each other and cannot be measured correctly.

[0008] The problem addressed by this disclosure is to provide a photometric device that can narrow the spacing between multiple measurement areas and improve measurement accuracy. Furthermore, it is to provide a method for inspecting displays using this photometric device.

[0009] To solve the above problems, the photometric apparatus of the present disclosure comprises an objective optical system that collects and forms an image of light from a plurality of predetermined regions, a plurality of light guiding members having an entrance port at the imaging position of the objective optical system for each predetermined region, and guiding the light of the image formed in each predetermined region by internal reflection, and a light receiving unit that receives the light emitted from the exit ports of the plurality of light guiding members.

[0010] The display inspection method of the present disclosure comprises the steps of using the photometric device to photometer the area on which the under panel solution is mounted and other adjacent areas as predetermined areas, or the steps of photometering the area on which the display is folded and other adjacent areas as predetermined areas.

[0011] According to this disclosure, the spacing between multiple measurement areas can be narrowed, and the accuracy of the measurement can be improved.

[0012] This is a block diagram illustrating the schematic configuration of a photometric device. This is a schematic diagram showing an example configuration of the objective optical system, light guide member, and light receiving unit. This is a schematic diagram showing an example of a field diaphragm. This is a schematic diagram showing an example of a mechanism for changing the position of the light guide member. This is an explanatory diagram of internal reflection in the light guide member. This is an explanatory diagram of an experiment on the emission angle. This is a graph showing the relationship between the angle of emitted light and the relative intensity when the total length of the optical fiber is changed. This is a cross-sectional view of a bundled fiber. This is a perspective view showing the appearance of a bundled fiber. This is an explanatory diagram explaining how the measurement results change depending on the positional relationship between the generated image and the optical fiber. This is a schematic diagram showing an example of a spectroscopic unit. This is a schematic diagram showing an example of an object to be measured. This is a schematic diagram showing an example of an object to be measured. This is a schematic diagram showing the configuration of the objective optical system, light guide member, and light receiving unit in Modification 1. This is a schematic diagram showing the configuration of the objective optical system, light guide member, and light receiving unit in Modification 2. This is a schematic diagram showing the configuration of the objective optical system, light guide member, and light receiving unit in Modification 3. This is a schematic diagram showing the configuration of the objective optical system, light guide member, and light receiving unit in Modification 4. This is a schematic diagram showing the configuration of the objective optical system, light guide member, and light receiving unit in Modification 5. This is a schematic diagram showing the first measurement area and the second measurement area in Modification 6. This is a schematic diagram showing the configuration of the light guide member and light receiving unit in Modification 6.

[0013] Hereinafter, one or more embodiments of this disclosure will be described with reference to the drawings. However, the scope of this disclosure is not limited to the disclosed embodiments.

[0014] [Photometric Device] Figure 1 is a block diagram showing the schematic configuration of the photometric device 100 in this embodiment. The object to be measured 1 is a light-emitting body, and may be, for example, a display, an electronic device equipped with a display, etc. A coloriluminance meter is an example of the photometric device 100 and can measure the color and brightness of the light-emitting body in the object to be measured 1. If the object to be measured 1 is not a light-emitting body, the photometric device 100 may include, for example, an illumination device that irradiates the object to be measured 1 with illumination light in a predetermined geometry. The geometry is not limited, but one example is 45°:0°.

[0015] The photometric device 100 comprises a probe 10 and a control processing unit 50. In the photometric device 100 shown in Figure 1, photometric measurements are taken on two predetermined areas of the object to be measured 1, but the number of predetermined areas may be three or more. In this specification, the predetermined areas to be photometrically measured are also referred to as "measurement areas." The area and measurement angle of the multiple measurement areas are not particularly limited and may differ for each measurement area. However, from the viewpoint of improving the accuracy of measurement, it is preferable that the measurement angles are all the same.

[0016] The probe 10 has an objective optical system 11, a first light guide member 12A, a first light receiving unit 13A, a first signal processing unit 14A, and a first calculation unit 15A for measuring a first measurement area RA. The probe 10 has an objective optical system 11, a second light guide member 12B, a second light receiving unit 13B, a second signal processing unit 14B, and a second calculation unit 15B for measuring a second measurement area RB.

[0017] The objective optical system 11 focuses and images light from the first measurement area RA and light from the second measurement area RB, respectively. The first light guide member 12A has an entrance opening at the position where the light from the first measurement area RA is imaged by the objective optical system 11. The first light guide member 12A guides the imaged light from the first measurement area RA by internal reflection. The first light receiving unit 13A receives the light emitted from the exit opening of the first light guide member 12A, converts the received light into an electrical signal (analog signal) with an intensity corresponding to the intensity of the light.

[0018] In this embodiment, the "imaging position" includes the position where light from the measurement area is imaged by the objective optical system and its vicinity. Here, "nearby" refers to a position that is slightly shifted from the imaging position but has the same optical function as the imaging position. The width of the neighborhood is 10% of the focal length of the objective optical system. For example, if the focal length of the objective optical system is 50 mm, the neighborhood refers to 5 mm before and after the imaging position. This degree of shift does not practically affect the measurement results of the photometric device 100.

[0019] The first signal processing unit 14A includes an amplifier (not shown) that amplifies the electrical signal from the first light receiving unit 13A, and an A / D converter (not shown) that converts the analog signal from the amplifier into a digital signal (measurement data). The first calculation unit 15A performs predetermined calculation processing using the digital signal (measurement data) output from the A / D converter. This calculates tristimulus values ​​(X, Y, Z), xyY (chromaticity coordinates, luminance) as defined by the CIE (International Commission on Illumination), TΔuvY (correlated color temperature, color difference from blackbody locus, luminance), etc.

[0020] The second light guide member 12B, the second light receiving unit 13B, the second signal processing unit 14B, and the second calculation unit 15B in the second measurement area RB also have the same functional configuration as the parts in the first measurement area RA. Hereafter, when the measurement area R is not distinguished, the notation of A and B in each reference numeral will be omitted.

[0021] The control processing unit 50 includes a control unit 51, a display unit 52, an operation unit 53, and a storage unit 54. The control processing unit 50 is implemented, for example, by a personal computer. The control unit 51 controls the probe 10. The control unit 51 receives data from the probe 10 and performs processing such as displaying and managing the data. The display unit 52 displays the measurement data in the form of a graph, list, etc., under the control of the control unit 51. The user inputs various information related to the measurement (measurement instructions, display mode settings, measurement range, etc.) from the operation unit 53. The storage unit 54 stores various data, including the measurement data.

[0022] Figure 2 is a schematic diagram showing an example configuration of the objective optical system 11, light guide member 12, and light receiving unit 13 according to this embodiment. The X-axis represents the optical axis direction of light from the measurement area R, and the Y-axis represents the direction perpendicular to this optical axis direction.

[0023] The objective optical system 11 is common to all measurement regions R, and multiple light guide members 12 and light receiving units 13 are provided for each measurement region R. In the example shown in Figure 2, the objective optical system 11 has a first objective lens 111 and a second objective lens 112. The objective lenses have positive power and collect light from the measurement region and guide it to the light guide member 12. The number of objective lenses is not particularly limited and may be one or three or more.

[0024] The photometer 100 may have an aperture diaphragm 113. Having an aperture diaphragm 113 allows adjustment of the numerical aperture (brightness) of light from the measurement area, but in this embodiment, it is not necessary to have an aperture diaphragm 113. When there is one objective lens, the aperture diaphragm 113 is placed at the rear focal position of the objective lens so that the measurement angle is constant regardless of the measurement position. When there are two objective lenses, the rear focal position of the first objective lens 111 and the front focal position of the second objective lens 112 are made to coincide, and the aperture diaphragm 113 is placed at this position so that the measurement angle is constant regardless of the measurement position.

[0025] Here, "front side" refers to the side closer to the object being measured 1 in the direction of the optical axis (X-axis), and "back side" refers to the side closer to the light guide member 12. Also, "focal position" here includes the focal position and its vicinity. Here, "neighborhood" refers to a position that has the same optical function as the focal position, as described above. The width of the neighborhood is 10% of the focal length of the objective optical system. For example, if the focal length of the objective optical system is 50 mm, the neighborhood refers to 5 mm in front of and behind the focal position.

[0026] The photometric device 100 may have a field aperture 16 between the objective optical system 11 and the light guide member 12. If the shape of the measurement area R is limited by the shape of the entrance L1 in the light guide member 12 without providing a field aperture 16, the spacing between multiple measurement areas R can be narrowed, and the spacing can be brought close to zero, by bringing the entrance L1s of multiple light guide members 12 close together in the YZ plane.

[0027] When a field diaphragm 16 is provided, it is positioned at the imaging position of the measurement area R relative to the objective optical system 11. In other words, the field diaphragm 16 and the entrance L1 of the light guide member 12 are located approximately at the same position. As a result, light from multiple measurement areas R is guided to the corresponding openings 161 of the field diaphragm 16. Even if the light from each measurement area R intersects before entering the photometric device 100, it is separated again by the field diaphragm 16. Therefore, multiple close measurement areas R can be measured while maintaining a working distance between the measurement areas R and the photometric device 100.

[0028] By providing the field diaphragm 16, the shape (shape and size) of the measurement area R can be adjusted. Furthermore, by providing the field diaphragm 16, even if the shapes of multiple measurement areas R are different, each can be adjusted, so a light guide member 12 with the same shape of the entrance L1 can be used for multiple measurement areas R.

[0029] Figure 3 is a schematic diagram showing an example of a field diaphragm 16. In Figure 3, the direction perpendicular to the plane of the paper is the direction of light propagation from the measurement area R. The field diaphragm 16 has an opening 161 for each measurement area R. In the example shown in Figure 3, the first opening 161A corresponds to the first measurement area RA, and the second opening 161B corresponds to the second measurement area RB. The shape of the opening 161 is not limited and can be set to any shape such as a circle, ellipse, or square depending on the shape of the measurement area R.

[0030] The field diaphragm 16 preferably has a variable mechanism that can change at least one of the position and shape of the aperture 161. This allows the shape of the measurement area R to be changed as needed. By changing at least one of the position and shape of the aperture 161, the shape of the measurement area R that can be measured by the photometric device 100 or the spacing between multiple measurement areas R can be changed. The position and shape of the aperture 161 may be changed manually or automatically using a motor or the like.

[0031] When changing the position of the aperture 161, the positions of the light guide member 12 and the light receiving unit 13 may also be changed. However, from the viewpoint of simplifying the configuration within the photometric device 100, it is preferable to change only the position of the light guide member 12 and not the position of the light receiving unit 13. If the light guide member 12 is flexible, the position of the light guide member 12 can be changed without changing the position of the light receiving unit 13. Alternatively, the light guide member 12 may be fixed to the field diaphragm 16. In this case, the position of the light guide member 12 can be easily changed in conjunction with changes in the position and shape of the aperture 161.

[0032] Figure 4 is a schematic diagram showing an example of a mechanism for changing the position of the light guide member 12. The light guide member 12 is passed through the central hole in the retaining plate 123 and extends perpendicular to the plane of the paper. Figure 4 shows a cross-section of the light guide member 12. The light guide member 12 can be moved inside the hole 122 in the direction of the arrow, and the position of the light guide member 12 can be fixed by fixing the retaining plate 123 to the fixing plate 121 with screws 124 at both ends.

[0033] The light guide member 12 is preferably bent so as to spread in the positive or negative direction within the YZ plane, as shown in Figure 2. Specifically, "bent" here means that the central axis of the entrance port L1 and the central axis of the exit port L2 do not coincide. By bending the light guide member 12 so as to spread in the Y-axis direction, more space can be secured for installing the light receiving unit 13.

[0034] In this embodiment, the light guide member 12 guides light from each measurement area by internal reflection. Since light is guided as long as it can be reflected inside the light guide member 12, the shape of the light guide member 12 is not restricted. In other words, by making the light guide member 12 a member that guides light by internal reflection, the light receiving unit 13 can be placed at any position. As a result, the spacing of the measurement areas R can be narrowed.

[0035] The light guide member 12 and the light receiving unit 13 will be described in detail below.

[0036] (Light Guide Member) The light guide member 12 is not limited as long as it guides the light of the entire image formed in each measurement area by internal reflection. The light guide member 12 can be one that is commonly used as a light guide, such as an optical fiber or a light pipe. However, a bundle of multiple optical fiber strands does not qualify as the light guide member 12 in this embodiment because each optical fiber guides a portion of the light of the image and cannot guide the light of the entire image at once.

[0037] An optical fiber has a core and a cladding layer. The optical fiber utilizes the difference in refractive index between the core and the cladding layer to guide light incident from the entrance L1 through total internal reflection, and the guided light is emitted from the exit L2. The cladding layer is located on the outer periphery of the core and covers the radially outward side of the core. The optical fiber may be further covered with a protective resin outside the cladding layer. The materials contained in the core and cladding layer are not particularly limited and include resins, glass, and the like.

[0038] Optical fibers are extremely thin and, by having a length greater than or equal to their diameter, their flexibility can be further enhanced.

[0039] The rod-shaped light pipe utilizes the difference in refractive index between the contained material and air to totally reflect light entering from the entrance port L1 and guide the guided light from the exit port L2. The material contained in the rod-shaped light pipe is not particularly limited and can be resin, glass, etc. The rod-shaped light pipe may be bent after being formed into a straight shape, but since its cross-sectional area is larger than that of an optical fiber and it is difficult to bend, it may be bent during the molding process. The cross-sectional shape of the rod-shaped light pipe is not particularly limited and can be a triangle, square, hexagon, etc. Furthermore, the rod-shaped light pipe may be tapered with different cross-sectional areas at both ends. In a tapered light pipe, the cross-sectional area of ​​the entrance port L1 is made relatively large, and the cross-sectional area of ​​the exit port L2 is made relatively small. This allows for more space to be secured for the light receiving unit 13.

[0040] A hollow light pipe has an inner surface that is a mirror surface that reflects light, and guides light that enters from the entrance port L1 by mirror reflection, and the guided light is emitted from the exit port L2. The material contained in the hollow light pipe is not particularly limited, as long as it has at least a mirror surface on its inner surface. For example, materials for a hollow light pipe include metal, resin, and glass. Since it is difficult to bend a hollow light pipe after it has been formed into a straight shape, it is preferable to bend it during the molding process.

[0041] Inside the light guide member 12, light is repeatedly reflected, so that light incident from any position at the incident port L1 is emitted from the emission port L2 with substantially uniform intensity. That is, the difference in intensity due to the incident position is mixed by internal reflection, and the intensity distribution is likely to be uniformized. By the light receiving unit 13 receiving the uniformized emitted light, the accuracy of measurement is improved. Details will be described later.

[0042] FIG. 5 is an explanatory diagram of internal reflection in the light guide member 12. Light incident at a certain position of the incident port L1 is guided to the emission port L2 by repeatedly reflecting inside the light guide member 12, and is emitted substantially uniformly from the entire surface of the emission port L2. That is, the incident position is uniformized.

[0043] In the explanatory diagram shown in FIG. 5, although the incident position is uniformized, the incident angle is not uniformized. However, actually, it has been found that the incident angle is also uniformized as described below. In the light guide member 12, local differences in refractive index (ripples), local differences in optical fiber diameter (thick or thin), etc. are likely to occur. Also, in the light guide member 12, curvature of the reflection surface due to bending of the optical fiber, distortion of the material (refractive index), etc. are likely to occur. Due to these factors, when the optical fiber has a certain length, actually, it is not reflected in the ideal shape as shown in FIG. 5, and the incident angle is also randomly uniformized.

[0044] The following experiment was conducted on the angle of light emitted from a bent optical fiber. FIG. 6 is an explanatory diagram of the experiment of the emission angle. Parallel light with a difference of ±2 degrees or less was made incident from the incident port L1 of the bent optical fiber 125. The intensity at each angle of the light emitted from the emission port L2 was measured by changing the angle (cone angle) from the central axis of the optical fiber with a luminance meter (not shown) installed at the emission port L2. The intensity was taken as the relative intensity, and the peak intensity was taken as 1. The optical fiber was bent at one place by 90°. The optical fiber 125 was a plastic fiber with a numerical aperture (NA) of 0.5 and a diameter of 1 mm, and the length was changed to 30 mm, 50 mm, 100 mm, and 300 mm, respectively.

[0045] FIG. 7 is a graph showing the relationship between the angle and relative intensity of the emitted light when the length of the optical fiber 125 is changed. For the optical fiber 125 with a length of 50 mm, the effective aperture angle (width at 5% of the peak intensity) is about ±35°, and even if the length is increased to 50 mm or more, there is almost no change in the aperture angle and it is stable. On the other hand, for the optical fiber 125 with a length of 30 mm, the intensity distribution of the emitted light becomes narrow and the degree of uniformity is low.

[0046] However, these experimental data are the results when parallel light is incident. In reality, the light from the measurement region has variations in angle. That is, this experimental condition (parallel light incidence) is the experimental data under the most severe conditions. Therefore, in the actual photometric device 100, if the length of the optical fiber 125 is 30 mm or more, the incident angle can be sufficiently uniformized. That is, if the length of the optical fiber 125 is 30 times or more of the diameter, the incident angle can be sufficiently uniformized. Also, in reality, due to the repetition of such random reflections, the polarization characteristics in the incident light are also uniformized. If the length of the optical fiber 125 is 30 times or more of the diameter, the emitted light can be sufficiently made unpolarized.

[0047] In the photometric device 100, the plurality of light guiding members 12 do not necessarily have to be of the same material and shape. If necessary, light guiding members 12 having different materials or shapes may be combined.

[0048] (Light receiving unit) The light receiving unit 13 is not particularly limited as long as it can receive the light emitted from the emission ports L2 of the plurality of light guiding members 12. In an example shown in FIG. 2, the light receiving unit 13 has a light beam branching member 131 and a light receiving part 132. For example, when only the luminance in the measurement region R is measured and the chromaticity is not measured, there is no need to branch the light emitted from the emission port L2 of the light guiding member 12, and the light receiving unit 13 does not necessarily have to have the light beam branching member 131. [[ID=~1]]

[0049] Examples of optical beam branching members include bundled fibers, lenses, and mirrors. Alternatively, the same number of single-wire optical fibers as the number of optical beam branches may be bundled together at the entrance and used as an optical beam branching member. In this case, it is preferable that the single-wire optical fibers have a larger cross-sectional diameter than the optical fibers used in the bundled fibers.

[0050] Let's explain bundled fibers. Figure 8 is a cross-sectional view of a bundled fiber, and Figure 9 is a perspective view showing the external appearance of a bundled fiber. A bundled fiber is a component in which multiple optical fibers, each approximately 0.03 to 0.07 mm in thickness, are bundled together at one end (the entrance) and then bundled into three separate bundles at the other end (the exit). If the relationship between the entrance and exit positions of the bundled optical fibers is biased, the emitted light will also be biased; therefore, the multiple optical fibers are randomly woven together.

[0051] As shown in Figure 8, in bundled fibers, there is a gap between the optical fibers, and the light of the image generated in this gap cannot be guided. Therefore, if light with specific optical properties is incident unevenly in this gap, the measurement results will change significantly depending on the positional relationship between the generated image and the optical fiber.

[0052] Figure 10 is an explanatory diagram illustrating how the measurement results change depending on the positional relationship between the generated image and the optical fiber when the bundle fiber is located at the imaging position of the objective optical system 11, i.e., in a conventional configuration without a light guide member 12. The light-emitting dots of the object under test 1 emit light in RED, GREEN, and BLUE, respectively, and these three dots form one pixel. Images D11-D16 and D21-D26 correspond to the light-emitting dots of the object under test 1, respectively, and images P11-P12 and P21-P22 correspond to the light-emitting pixels of the object under test 1, respectively. For the sake of explanation, images D11-D16 and D21-D26 are assumed to be rectangles, and the radii of the optical fibers F11-F13 and F21-F23 are assumed to be the same as the shorter sides of images D11-D16 and D21-D26. Furthermore, the thickness of the cladding layer in optical fibers F11-F13 and F21-F23 will not be considered.

[0053] In image P11, the areas of images D11 to D13 (RGB) are all the same, and of these, the areas of images D11 to D13 that overlap with the entry points of optical fibers F11 to F12 are also all the same. The same is true for image P12. On the other hand, in image P21, the positional relationship with the optical fibers is different compared to image P11. In image P21, the areas of images D21 to D23 (RGB) are all the same, but of these, the areas of images D21 to D23 that overlap with the entry points of optical fibers F21 to F22 differ for each image, and the area of ​​the image overlapping with the entry points of optical fibers F21 to F22 in image D22 is smaller than that of images D21 and D23. In other words, because there is a bias in the incident light to the optical fibers, differences in measurement values ​​occur depending on the positional relationship between the generated image and the optical fibers.

[0054] When the image corresponding to the generated light-emitting pixel is much larger or much smaller than the entrance of the optical fiber, the difference caused by the positional relationship between the generated image and the optical fiber is relatively small. However, in a relatively small measurement area R (for example, about 2 to 8 mm in diameter) as assumed in this embodiment, there is little difference in size between the generated image and the entrance of the optical fiber, and the difference caused by the positional relationship between the generated image and the optical fiber is relatively large.

[0055] However, in this embodiment, it is sufficient to measure the entire measurement area rather than measuring each light-emitting pixel within the measurement area. In this embodiment, light emitted from the light guide member 12 is incident on the bundle fiber. Because the light emitted from the light guide member 12 is uniform light, sufficient accuracy can be obtained even if the light beam is then split using the bundle fiber and measured for each split light beam.

[0056] The entrance of the light beam branching member 131 is made to have the same shape as or larger than the exit opening L2 of the light guide member 12, so that the light emitted from the light guide member 12 can be guided to the light beam branching member 131 without leakage. However, the light beam branching member 131 cannot branch the light beam under appropriate conditions unless light is incident on its entrance to a certain extent uniformly. Since light with an angle according to the numerical aperture is emitted from the exit opening L2 of the light guide member 12, the entrance of the light beam branching member 131 and the exit opening L2 of the light guide member 12 are arranged with a predetermined distance between them. This allows the light emitted from the exit opening L2 to be incident on the entrance of the light beam branching member 131 to a certain extent uniformly.

[0057] As an example, let R1 [mm] be the diameter of the light guide member 12, NA [°] be the numerical aperture, and R2 [mm] be the diameter of the entrance of the light beam branching member 131. In this case, the optimal distance between the entrance of the light beam branching member 131 and the exit L2 of the light guide member 12 can be expressed by the following formula: Formula (1) Distance [mm] = {(R2 - R1) / 2} / tan(NA)

[0058] The exit port L2 of the light guide member 12 and the entrance port of the light beam branching member 131 may be in contact if they have the same area. By being in contact, the light guide member 12 and the light beam branching member 131 may be integrated.

[0059] The light-receiving unit 132 has a light-receiving sensor. In one example shown in Figure 2, the light-receiving unit 132 has three filters 133 and three sensors 134. The three sensors 134 are, for example, silicon photocells (SPCs) and have substantially the same light-receiving sensitivity. The light-receiving unit 132 may also have a focusing lens. The focusing lens is located between the light beam branching member 131 and each filter 133.

[0060] Filters 133-1, 133-2, and 133-3 are color filters that transmit light emitted from the light beam branching member 131 with predetermined transmittance characteristics. Specifically, filters 133-1, 133-2, and 133-3 are filters having spectral transmission characteristics corresponding to the color matching functions X, Y, and Z as defined by the International Commission on Illumination (CIE), and are, for example, interference film filters.

[0061] Sensors 134-1, 134-2, and 134-3 each receive light that has passed through filters 133-1, 133-2, and 133-3, respectively. Sensors 134-1, 134-2, and 134-3 each output received signals corresponding to tristimulus values ​​(X, Y, Z). The signals from sensors 134-1, 134-2, and 134-3 are input to the signal processing unit 14.

[0062] In other embodiments, the light receiving unit 132 may include, for example, a filter corresponding to a standard luminous efficiency defined by the International Commission on Illumination (CIE) and a sensor. The sensor receives light transmitted through the filter and outputs an electrical signal corresponding to the received light intensity. The signal from the sensor is input to the signal processing unit 14.

[0063] In other embodiments, the light receiving unit 13 may have, for example, a spectral unit. Figure 11 is a schematic diagram showing an example of a spectral unit 70. The spectral unit 70 has a diffraction grating 72 and a line sensor 73. The diffraction grating 72 is a light beam branching member that branches the light beam at predetermined wavelengths. The line sensor 73 consists of multiple sensors connected in a straight line, that is, multiple light receiving parts combined into one. The line sensor 73 receives light whose wavelengths have been dispersed by diffraction, and the number of sensors corresponds to the number of light beam branches.

[0064] The spectral unit 70 may have a lens 71. Light emitted from the light guide member 12 passes through the incident slit 74 and enters the spectral unit 70. The diffraction grating 72 is of the reflective type, and the incident light is diffracted and reflected by the diffraction grating 72. The light reflected by the diffraction grating 72 enters the lens 71 and is imaged as a wavelength-dispersive image on the light-receiving surface of the line sensor 73 by the lens 71. The line sensor 73 outputs an electrical signal corresponding to the imaged wavelength-dispersive image. The signal from the line sensor 73 is input to the signal processing unit 14.

[0065] Within the photometric device 100, the multiple light-receiving units 13 do not all have to have the same configuration, material, and shape. If necessary, light-receiving units with different configurations, materials, or shapes may be combined. For example, of the two light-receiving units 13, one light-receiving unit 13 may receive light branched by the light beam branching member 131 to acquire tristimulus values, while the other light-receiving unit 13 may receive light by the spectral unit 70 to acquire spectral data.

[0066] [Object under measurement] Figure 12 is a schematic diagram showing an example of an object under measurement 1. The object under measurement 1 is, for example, a smartphone and has a display 2 equipped with a UPS (Under Panel Solution). Behind the display 2, for example, a camera (not shown) is mounted. The size of the camera is not particularly limited, but for example, it is about 4 mm in height and 14 mm in width. The area behind where the camera is mounted is called the UPS section 3, and the area where the camera is not mounted is called the non-UPS section 4. As mentioned above, for example, when adjusting the gamma of the display 2, it is preferable that the measurement area 31 of the UPS section and the measurement area 41 of the non-UPS section be set as close together as possible. Brightness and the like are measured in these measurement areas. Note that in Figure 11, the measurement area 31 of the UPS section is selected as a part of the UPS section 3, but the entire UPS section 3 may be used as the measurement area.

[0067] The area of ​​the UPS section 3 in the display is very narrow, and the measurement area 31 of the UPS section is also very narrow. On the other hand, the area of ​​the non-UPS section 4 in the display is wide, so the measurement area 41 of the non-UPS section does not necessarily need to be as narrow as the measurement area 31 of the UPS section. Furthermore, from the viewpoint of obtaining sufficient light for measurement and improving accuracy, it is preferable that the measurement area 41 of the non-UPS section be somewhat wide.

[0068] In Figure 12, the measurement area 31 of the UPS section and the measurement area 41 of the non-UPS section are shown as circular, but the shape is not particularly limited and may be rectangular. The width w1 of the measurement area 31 of the UPS section is, for example, 3 mm. The width w2 of the measurement area 41 of the non-UPS section is, for example, 5 mm. The distance D between the center of the measurement area 31 of the UPS section and the center of the measurement area 41 of the non-UPS section, i.e., the interval D of the measurement distance, is, for example, 10 mm. In the photometering device 100 of this embodiment, accurate photometry can be performed even if the area and spacing between multiple measurement areas are relatively small. Furthermore, the performance of the display can be inspected from the photometry results.

[0069] Figure 13 is a schematic diagram showing an example of an object to be measured 1. The object to be measured 1 is, for example, a smartphone and has a foldable display 2. The display 2 can be folded in half with its center line as the folding point. The area of ​​the display 2 that is folded, i.e., the area near the center line of the display 2, is called the folded portion 6. The area of ​​the display 2 that is not folded, i.e., the area of ​​the display 2 excluding the folded portion 6, is called the unfolded portion 8. From the viewpoint of reducing the influence of the in-plane light emission distribution in the display, it is preferable that the measurement area 61 of the folded portion and the measurement area 81 of the unfolded portion be set as close together as possible. Brightness and the like are measured in these measurement areas R. In Figure 12, the measurement area 61 of the folded portion is selected as the measurement area R of the folded portion, but the entire folded portion 6 may also be used as the measurement area R.

[0070] The area of ​​the bent portion 6 in the display is very narrow, and the measurement area 61 of the bent portion is also very narrow. On the other hand, the area of ​​the non-bent portion 8 in the display is wide, so the measurement area 81 of the non-bent portion does not necessarily need to be as narrow as the measurement area 61 of the bent portion. Furthermore, from the viewpoint of obtaining sufficient light for measurement and improving accuracy, it is preferable that the measurement area 81 of the non-bent portion be somewhat wide.

[0071] [Display Inspection Method] The photometer 100 of this embodiment can accurately measure light in multiple measurement areas, even if the area is relatively small and the spacing is narrow. For displays equipped with a UPS, the UPS section 3 and the non-UPS section 4 are measured separately. The performance of the display can be inspected from the photometering results. For foldable displays, the foldable section 6 and the non-foldable section 8 are measured separately. The performance of the display can be inspected from the highly accurate photometering results. In other words, the accuracy of display inspection can be improved.

[0072] The following describes some of the variations of this disclosure.

[0073] [Modification 1] Figure 14 is a schematic diagram showing the configuration of the objective optical system 11, the light guide member 12, and the light receiving unit 13 in Modification 1. In Modification 1, the light receiving unit 13 does not have a light beam branching member, and the light emitted from the light guide member 12 is received by the light receiving unit 132. In Modification 1, the lengths of the first light guide member 12A and the second light guide member 12B are different. The light emitted from the exit port of the first light guide member 12A travels in a straight line and is received by the light receiving unit 132A. On the other hand, the light emitted from the exit port of the second light guide member 12B travels in a straight line, is reflected by the mirror 135B, and is received by the light receiving unit 132B. In this way, the first light guide members 12A and 12B are used, and the optical path of the light emitted from the second light guide member 12B is changed by the mirror 135B. This allows for a narrower spacing between measurement areas while still providing sufficient space for the light-receiving unit 13.

[0074] [Modification 2] Figure 15 is a schematic diagram showing the configuration of the objective optical system 11, the light guide member 12, and the light receiving unit 13 in Modification 2. In Modification 2, the light guide member 12 is not bent and is straight. If sufficient space can be secured for the light receiving unit 13 while narrowing the spacing of the measurement area R, the light guide member 12 does not necessarily need to be bent. Also, in Modification 2, since the light from the measurement area R is made uniform by the light guide member 12, the influence of positional errors in the bundle fiber caused by the small area of ​​the measurement area R can be reduced.

[0075] [Modification 3] Figure 16 is a schematic diagram showing the configuration of the objective optical system 11, the light guide member 12, and the light receiving unit 13 in Modification 3. In Modification 3, the lengths of the first light guide member 12A and the second light guide member 12B are different. Light emitted from the exit port of the first light guide member 12A travels straight ahead and enters the collimating lens 136A. Parallel light emitted from the collimating lens 136A is received by the light receiving unit 132A. The collimating lens 136A is a light beam branching member that branches the light beam according to the angle of incidence.

[0076] Light incident on the collimating lens 136A at a relatively large angle of incidence, moving away from the second light-receiving unit 13B, is received by sensor 132A-1. Light incident on the collimating lens 136A at a relatively large angle of incidence, moving towards the second light-receiving unit 13B, is received by sensor 132A-3. Light incident on the collimating lens 136A at a relatively small angle of incidence is received by sensor 132A-2. In other words, if the light incident on the collimating lens 136A has angular characteristics, the collimating lens 136A cannot uniformly branch the light beam and is affected by the angular characteristics. However, in modified example 3, the light incident on the collimating lens 136A is homogenized by the first light guide member 12A, and in particular, its angular characteristics are made uniform, so accurate measurements can be taken even when the collimating lens 136A is used as a light beam branching member.

[0077] Meanwhile, light emitted from the exit port of the second light guide member 12B travels in a straight line and is reflected by the mirror 135B. A portion of the light reflected by the mirror 135B is reflected by the half mirror 137B-1 and received by the light receiving unit 132B-1. A portion of the light that passes through the half mirror 137B-1 is reflected by the half mirror 137B-2 and received by the light receiving unit 132B-2. The light that passes through the half mirror 137B-2 is received by the light receiving unit 132B-3. The reflection:transmission ratio of the half mirror 137B-1 is 1:2, and the reflection:transmission ratio of the half mirror 137B-2 is 1:1. The half mirror 137B is a light beam branching member that branches the light beam so that the amount of light is equal.

[0078] The half mirror 137B is generally affected by polarization in light transmission. That is, if the light incident on the half mirror 137B has polarization characteristics, the half mirror 137B cannot uniformly branch the light beam and is affected by the polarization characteristics. However, in modified example 3, the light incident on the half mirror 137B is made uniform by the second light guide member 12B, and in particular, the polarization characteristics are made uniform, so accurate measurements can be taken even when the half mirror 137B is used as a light beam branching member. In addition, the optical path of the light emitted from the second light guide member 12B is changed by the mirror 135B. This makes it possible to narrow the spacing of the measurement area R while securing sufficient space for installing the light receiving unit 13.

[0079] [Modification 4] Figure 17 is a schematic diagram showing the configuration of the objective optical system 11, the light guide member 12, and the light receiving unit 13 in Modification 4. In Modification 4, the light guide member 12 is not bent, but it is tapered. In Modification 4, the tapered shape of the second light guide member 12B makes it easier to secure space for the light receiving unit 13 at the output port. The configuration of the first light receiving unit 13A is as described in Modification 3.

[0080] [Modification 5] Figure 18 is a schematic diagram showing the configuration of the objective optical system 11, the light guide member 12, and the light receiving unit 13 in Modification 5. In Modification 5, the second measurement area RB receives light from three measurement areas RB-1, RB-2, and RB-3, which is uniformly distributed by the second light guide member 12B and received by a single second light receiving unit 13B. The second light guide member 12B consists of multiple single-wire optical fibers, which may be integrated together. Light enters the core portion of the optical fiber and does not enter the cladding layer. As a result, the cladding layer has the same function as a field diaphragm that adjusts the shape of the measurement area R, and the second measurement area RB can be divided into three measurement areas RB-1, RB-2, and RB-3.

[0081] For example, Modification 5 can be used for measurements in a foldable display as shown in Figure 13, where the three measurement areas 61 of the folds correspond to the three measurement areas RB-1, RB-2, and RB-3. These three measurement areas do not need to be measured individually; by measuring them together, the average brightness, chromaticity, etc., of the folds 6 can be measured. In Modification 5, the second measurement area RB is subdivided into three parts, but it may be subdivided into four or more parts.

[0082] [Modification 6] Figure 19 is a schematic diagram showing the first measurement area RA and the second measurement area RB in Modification 6. As shown in Figure 19, the second measurement area RB may be set around the first measurement area RA for measurement. Figure 20 is a schematic diagram showing the configuration of the light guide member 12 and the light receiving unit 13 in Modification 6. The first light guide member 12A and the second light guide member 12B are brought together at the entrance. At the exit, the first light guide member 12A, which guides light from the first measurement area RA, emits light to the first light receiving unit 13A, and the second light guide member 12B, which guides light from the second measurement area RB, emits light to the second light receiving unit 13B. By using a single-wire optical fiber as the light guide member 12, it is possible to accommodate complex shapes of the measurement area.

[0083] In this embodiment, the configurations of the light guide member 12 and the light receiving unit 13 described above may be partially combined.

[0084] In this embodiment, the photometric device 100 includes an objective optical system 11 that collects and forms an image of light from multiple predetermined regions (measurement regions R). The photometric device 100 includes multiple light guide members 12, each having an entrance port L1 at the imaging position of the objective optical system 11 for each measurement region R, and guiding the light of the image formed for each measurement region R by internal reflection. The photometric device 100 includes a light receiving unit 13 that receives the light emitted from the exit ports L2 of the multiple light guide members 12. This makes it possible to narrow the spacing between the multiple measurement regions R and improve the accuracy of the measurement.

[0085] In this embodiment, it is preferable that the light receiving unit 13 has a light beam branching member 131 that branches the light emitted from the output port L2 of the light guide member 12 into multiple light beams, and the same number of light receiving units 132 as the number of light beam branches. This makes it possible to measure the chromaticity in the measurement area R. In addition, it is possible to narrow the spacing between the multiple measurement areas R and improve the accuracy of the measurement.

[0086] In this embodiment, it is preferable that the multiple light guide members 12 include bent light guide members. This allows for a narrower spacing between the multiple measurement regions R while still providing sufficient space for the light receiving unit 13.

[0087] In this embodiment, it is preferable that the multiple light guide members 12 include flexible optical fibers. This allows for a narrower spacing between the multiple measurement regions R while still providing sufficient space for the light receiving unit 13.

[0088] In this embodiment, the light emitted from multiple emission ports L2 in multiple light guide members 12 may be received by separate light receiving units 13. This allows measurement to be performed for each measurement area R.

[0089] In this embodiment, the light emitted from multiple emission ports L2 in multiple light guide members 12 may be received by a single light receiving unit 13. This allows for averaging and measurement of multiple measurement areas R.

[0090] In this embodiment, it is preferable that the objective optical system 11 is provided with a field diaphragm 16 at the imaging position, and the field diaphragm 16 has apertures 161 corresponding to a plurality of predetermined regions to be photometrically measured. This allows the shape of the measurement region R to be adjusted.

[0091] In this embodiment, it is preferable that the field diaphragm 16 has a variable mechanism that can change at least one of the position and shape of the aperture 161. This allows the shape of the measurement area R to be changed as needed.

[0092] In this embodiment, light emitted from multiple output ports L2 in multiple light guide members 12 is received by separate light receiving units 13. The light beam branching member 131 preferably includes multiple single-wire optical fibers or bundled fibers. This allows for sufficient space to install the light receiving units 13 while narrowing the spacing between multiple measurement areas R.

[0093] In this embodiment, it is preferable that the plurality of light guide members 12 include tapered light guide members in which the area of ​​the output port L2 is smaller than the area of ​​the input port L1. This makes it possible to narrow the spacing between the plurality of measurement areas R while ensuring sufficient space for installing the light receiving unit 13.

[0094] The display inspection method of this embodiment uses a photometric device 100. The display inspection method includes the step of photometrically measuring a predetermined area (measurement area R) consisting of the area on which the under panel solution is mounted (measurement area 31 of the UPS section) and the surrounding area (measurement area 41 of the non-UPS section). Alternatively, the display inspection method includes the step of photometrically measuring a predetermined area consisting of the area where the display is folded (measurement area 61 of the folded section) and the surrounding area (measurement area 81 of the non-folded section). This improves the accuracy of display inspection.

[0095] Furthermore, the detailed configuration and operation of each device constituting the photometric device may also be modified as appropriate, without departing from the spirit of this disclosure.

[0096] This disclosure makes it possible to narrow the spacing between multiple measurement areas and improve the accuracy of measurements in a photometric device that measures multiple areas.

[0097] 1. Object to be measured 2. Display 3. UPS section 31. Measurement area of ​​the UPS section 4. Non-UPS section 41. Measurement area of ​​the non-UPS section 6. Bent section 61. Measurement area of ​​the bent section 8. Non-bent section 81. Measurement area of ​​the non-bent section 10. Probe 11. Objective optical system 111. First objective lens 112. Second objective lens 113. Aperture diaphragm 12. Light guide member 121. Fixing plate 122. Hole 123. Retaining plate 124. Screw 125. Optical fiber 13. Light receiving unit 131. Light beam branching member 132. Light receiving section 133. Filter 134. Sensor 135B. Mirror 136A. Collimating lens 137B. Half mirror 14. Signal processing unit 15. Calculation unit 16. Field diaphragm 161. Aperture 50. Control processing unit 51 Control unit 52 Display unit 53 Operation unit 54 Memory unit 70 Spectroscopic unit 71 Lens 72 Diffraction grating 73 Line sensor 74 Entrance slit 100 Photometer R Measurement area L1 Entrance port L2 Exit port

Claims

1. A photometric device comprising: an objective optical system that collects and forms an image of light from multiple predetermined regions; a plurality of light guiding members, each having an entry port at the imaging position of the objective optical system for each predetermined region, which guide the light of the image formed in each predetermined region by internal reflection; and a light receiving unit that receives the light emitted from the exit ports of the plurality of light guiding members.

2. The photometer according to claim 1, wherein the light receiving unit has a light beam branching member that branches the light emitted from the output port of the light guide member into a plurality of light beams, and a number of light receiving units equal to the number of light beam branches.

3. The photometric apparatus according to claim 1 or claim 2, wherein the plurality of light guide members include a bent light guide member.

4. The photometric apparatus according to claim 3, wherein the plurality of light guide members include flexible optical fibers.

5. The photometric apparatus according to claim 4, wherein light emitted from multiple emission ports of the multiple light guide members is received by each of the separate light receiving units.

6. The photometric apparatus according to claim 4, wherein light emitted from multiple emission ports of the multiple light guide members is received by a single light receiving unit.

7. The photometer according to claim 1 or 2, wherein the objective optical system is provided with a field diaphragm at the imaging position, and the field diaphragm has an opening corresponding to the plurality of predetermined regions to be photometered.

8. The photometer according to claim 7, wherein the field diaphragm has a variable mechanism that can change at least one of the position and shape of the aperture.

9. The photometric apparatus according to claim 2, wherein light emitted from multiple output ports in the multiple light guide members is received by each of the separate light receiving units, and the light beam branching member includes a plurality of single-wire optical fibers or bundled fibers.

10. The photometer according to claim 1 or 2, wherein the plurality of light guide members include a tapered light guide member in which the area of ​​the exit port is smaller than the area of ​​the entrance port.

11. The photometer according to claim 3, wherein the objective optical system is provided with a field diaphragm at the imaging position, and the field diaphragm has an opening corresponding to the plurality of predetermined regions to be photometered.

12. The photometer according to claim 11, wherein the field diaphragm has a variable mechanism that can change at least one of the position and shape of the aperture.

13. The photometric apparatus according to claim 3, wherein the light receiving unit has a light beam branching member that branches the light emitted from the output port of the light guide member into a plurality of light beams, and a number of light receiving units equal to the number of light beam branches, the light emitted from a plurality of output ports in the plurality of light guide members is received by a separate light receiving unit, and the light beam branching member includes a plurality of single-wire optical fibers or bundled fibers.

14. The photometric apparatus according to claim 3, wherein the plurality of light guide members include a tapered light guide member in which the area of ​​the output port is smaller than the area of ​​the input port.

15. A method for inspecting a display, comprising the steps of using the photometric apparatus described in claim 1 or claim 2 to photometer an area on which an under panel solution is mounted and other adjacent areas, respectively, as the predetermined area, or to photometer an area on which the display is folded and other adjacent areas, respectively, as the predetermined area.

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