Optical measurement device, color measurement system, color evaluation method, and program

Abstract

Provided are an optical measurement device, a color measurement system, a color evaluation method, and a program that visualize a change in color when a frame is switched as a change in a numerical value.　The optical measurement device comprises: a measuring unit that measures light from an object being measured at a sampling rate of 500 Hz or more; and a calculating unit that outputs synchronizable time-series color signals corresponding to measurement signals of each of an X component, a Y component, and a Z component of an XYZ color system.

Description

Light measurement device, color measurement system, color evaluation method and program

[0001] The present invention relates to an optical measurement device, a color measurement system, a color evaluation method, and a program.

[0002] As an optical measurement device for measuring the performance of a display, for example, a display color analyzer having an internal optical sensor is known (Patent Documents 1 and 2).

[0003] International Publication No. 2017 / 094562 Japanese Patent Application Laid-Open No. 2023-018536

[0004] When a display uses RGB light sources that emit light independently, there is a difference in the rise time of each color light source when it switches from off to on. This causes the displayed color to deviate from the intended color when switching frames. When the display is a liquid crystal display (LCD) with a color filter, the color switches simultaneously regardless of whether the backlight light source is on or off, so this color shift does not occur.

[0005] Conventional optical measurement devices measure the flicker performance of a display using only measurement data for one of the three stimulus values ​​of the XYZ color system (for example, stimulus value Y). When the light source of the display is monochromatic, the performance of the display can be measured using only measurement data for stimulus value Y. However, when the light source of the display is an RGB light source, evaluation of the above-mentioned color shift requires measurement data for each of stimulus values ​​X, Y, and Z, and conventional optical measurement devices cannot evaluate color shift.

[0006] An object of the present invention is to provide a light measurement device, a color measurement system, a color evaluation method, and a program that can suitably evaluate color shift in the case of a display that uses an RGB light source as its light source.

[0007] In order to solve the above problems, the optical measurement device of the present invention comprises a measurement unit that measures light from an object to be measured at a sampling rate of 500 Hz or more, and a calculation unit that calculates synchronous time-series color signals corresponding to the measurement signals of each of the X, Y, and Z components of the XYZ color system.

[0008] According to a second aspect of the present invention, in the first aspect of the present invention, color measurement is performed on a self-luminous color display that emits light of multiple colors independently.

[0009] The invention described in claim 3 is the invention described in claim 1 or 2, wherein the measurement unit includes a plurality of compensation filters and a plurality of first light-receiving sensors that receive light beams that pass through the plurality of compensation filters, respectively, and the plurality of compensation filters and the plurality of first light-receiving sensors have spectral sensitivities corresponding to the X component, the Y component, and the Z component of the color matching function, respectively.

[0010] The invention described in claim 4 is the invention described in claim 1 or 2, wherein the measurement unit includes a spectroscope and a second light receiving sensor having a plurality of pixels that receives light dispersed by the spectroscope.

[0011] A fifth aspect of the present invention is the first or second aspect of the present invention, further comprising a digital filter processing unit that performs frequency filtering on the digital signal output from the output unit of the measurement unit.

[0012] A sixth aspect of the present invention is the fifth aspect of the present invention, further comprising: a storage unit that stores frequency characteristics used in the frequency filter processing; and a reading unit that reads out the frequency characteristics from the storage unit.

[0013] According to a seventh aspect of the present invention, in the sixth aspect of the present invention, a conversion unit is further provided that converts the read frequency characteristics into impulse response characteristics.

[0014] The invention described in claim 8 is the invention described in claim 5, wherein the frequency filtering is processing using a temporal contrast sensitivity function.

[0015] A ninth aspect of the present invention is the eighth aspect of the present invention, wherein the temporal contrast sensitivity function is a sensitivity function based on the IDMS standard.

[0016] The invention according to claim 10 is the invention according to claim 5, further comprising a flicker index derivation unit that derives a flicker index based on the digital signal output from the output unit of the measurement unit.

[0017] The invention described in claim 11 is the invention described in claim 1 or 2, wherein the color signal calculated by the calculation unit is a signal of tristimulus values.

[0018] A twelfth aspect of the present invention is the image forming apparatus according to the first or second aspect, wherein the color signal calculated by the calculation unit is a chromaticity signal.

[0019] In a thirteenth aspect of the present invention, in the third aspect, the measurement section includes an integrating section that simultaneously integrates the measurement signal output from the first light receiving sensor.

[0020] According to a fourteenth aspect of the present invention, in the fourth aspect of the present invention, the measurement section includes an integrating section that simultaneously integrates the measurement signal output from the second light receiving sensor.

[0021] The color measurement system of the present invention is a color measurement system that performs color measurement of a self-luminous color display that emits multiple colors independently, and comprises: an emission setting unit that sets the emission conditions of the self-luminous color display; a measurement unit that measures light from an object to be measured at a sampling rate of 500 Hz or more; and a calculation unit that calculates synchronizable time-series color signals corresponding to measurement signals for each of the X, Y, and Z components of an XYZ color system, wherein the measurement unit comprises a plurality of compensation filters and a plurality of first light-receiving sensors that receive light beams that pass through the plurality of compensation filters, and the plurality of compensation filters and the plurality of first light-receiving sensors have spectral sensitivities corresponding to the X, Y, and Z components of a color matching function, respectively.

[0022] The color evaluation method of the present invention is a method for evaluating the color of a self-luminous color display that emits multiple colors independently, and includes: a setting step for setting the light emission conditions of the self-luminous color display; a measurement step for measuring light from an object to be measured at a sampling rate of 500 Hz or more; a calculation step for calculating synchronizable time-series color signals corresponding to the measurement signals for each of the X, Y, and Z components of the XYZ color system; and an evaluation step for comparing the steady state and non-steady state of the output time-series color signals to evaluate color changes at frame transitions.

[0023] The program of the present invention causes a computer of a color measurement system that performs color measurement on a self-luminous color display that emits multiple colors independently to execute an emission setting process that sets the emission conditions of the self-luminous color display, a measurement process that measures light from an object to be measured at a sampling rate of 500 Hz or more, and an arithmetic process that calculates synchronizable time-series color signals corresponding to the measurement signals for each of the X, Y, and Z components of the XYZ color system.

[0024] According to the present invention, color misregistration can be suitably evaluated in the case of a display using an RGB light source as the light source.

[0025] 1 is a perspective view showing the appearance of the optical measurement device 1 of this embodiment. FIG. 2 is a block diagram showing the internal configuration of the optical measurement device 1 shown in FIG. 1. FIG. 3 is a block diagram showing the configuration of the optical measurement device 1 of this embodiment. FIG. 4 is a diagram showing the specific configuration of the measurement optical system 27 and the light receiving system 28 shown in FIG. 2. FIG. 5 is a diagram showing the irradiation range of the light beam emitted from the optical fiber. FIG. 6 is a diagram showing a specific configuration in a spectrophotometric measurement. FIG. 7 is a diagram showing the relationship between the light emission time T and the current I in an OLED. Ｘ 1 is a graph showing the relationship between the light emission time T and the current I when an OLED display having a transient state is driven at a refresh rate of 10 Hz. Ｘ 1 is a graph showing the relationship between the light emission time T and the current I Ｘ 1 is a graph showing the relationship between the light emission time T and the current I when an OLED display having a transient state is driven at a refresh rate of 60 Hz, and the value obtained by superimposing the temporal contrast sensitivity function (TCSF) on the light emission time T.Ｘ 1 is a graph showing the relationship between the light emission time T and the current I Ｘ 1 is a graph showing the relationship between a value obtained by superimposing a temporal contrast sensitivity function (TCSF) on a color value Y. FIG. 2 is a flowchart showing the operation of the optical measurement device 1 of this embodiment. FIG. 3 is a diagram showing sensitivity data among the frequency characteristics of the eye. FIG. 4 is a diagram showing an example of frequency characteristics of the eye including phase characteristics. FIG. 5 is an example of an impulse response characteristic corresponding to a visual stimulus response. FIG. 6 is a graph showing continuous data of stimulus value intensity acquired for a display. FIG. 7 is an enlarged view showing a time period around the timing when the drive frequency changes from 60 Hz to 24 Hz. FIG. 8 is an enlarged view showing a time period around the timing when the drive frequency changes from 24 Hz to 60 Hz. FIG. 9 is a waveform diagram of an impulse response used in digital filter processing. FIG. 10 is a graph showing superimposed stimulus value data obtained by digital filter processing. FIG. 11 is a graph showing the time change of a flicker index value. FIG. 12 is a diagram showing an example of waveform distortion that can occur when using conventionally known discrete Fourier transform processing. FIG. 13 is a graph showing superimposed stimulus value data derived only for stimulus value Y. FIG. 14 is a graph showing superimposed stimulus value data derived for stimulus values ​​X, Y, and Z. FIG. 15 is a block diagram showing the configuration of a color measurement system 100 of this embodiment.

[0026] One or more embodiments of the present invention will now be described with reference to the drawings, however, it is not intended that the scope of the present invention be limited to the disclosed embodiments.

[0027] <First embodiment> [Configuration of optical measurement device 1] Fig. 1 is a perspective view showing the appearance of an optical measurement device 1 of this embodiment. The optical measurement device 1 shown in Fig. 1 is a tristimulus value type. Fig. 2 is a block diagram showing the internal configuration of the optical measurement device 1 shown in Fig. 1. Fig. 3 is a block diagram showing the configuration of the optical measurement device 1 of this embodiment.

[0028] The optical measurement device 1 is used, for example, in the inspection process of a manufacturing line for liquid crystal displays or organic light-emitting diode (OLED) displays. The optical measurement device 1 measures, for example, the color, brightness, light waveform (change in light amount), flicker, etc. of the display surface 12 of the measurement object.

[0029] 2 and 3, the optical measurement device 1 includes an objective lens 21, a beam splitter 24, a photoelectric conversion unit 25, an integrating unit 26, an A / D conversion unit 31, a storage unit 32, a control unit 36, an operation unit 39, a display unit 40, a power supply unit 37, and a communication unit 38.

[0030] Furthermore, the optical measurement device 1 may be connected to a personal computer (not shown) or the like, and in that case, the operation unit 39 and the display unit 40 may be provided in the personal computer.

[0031] In this embodiment, the objective lens 21, the beam splitter 24, the photoelectric conversion unit 25, the integrating unit 26, and the A / D conversion unit 31 function as a measurement unit 2, and the memory unit 32 and the control unit 36 ​​function as a calculation unit.

[0032] 2 is disposed, for example, at a predetermined distance (for example, 3 cm) opposite the display surface 12. The measurement unit 2 photoelectrically converts light from the display surface 12 into an electrical signal (analog signal).

[0033] The A / D converter 31 converts the electrical signal (analog signal) input from the integrator 26 into a digital signal. The calculator also performs predetermined calculations such as correction of dark output, and calculations such as tristimulus values ​​(X, Y, Z) or xyY (chromaticity coordinates, luminance) established by the International Commission on Illumination (CIE).

[0034] The control unit 36 ​​controls the photoelectric conversion unit 25, the integrating unit 26, the A / D conversion unit 31, the storage unit 32, the communication unit 38, the operation unit 39, and the display unit 40. The control unit 36 ​​also generates superimposed stimulus value data and derives a flicker index through processing described below. The control unit 36 ​​may be connected to a measurement object. By connecting to the measurement object, it is possible to set the light emission conditions of the object during measurement.

[0035] The measurement unit 2 will now be described in detail. Fig. 4 is a diagram showing the specific configuration of the measurement optical system 27 and the light receiving system 28 shown in Fig. 2. In the following description, measurements are performed using a tristimulus value direct reading type, but the measurement method is not limited to this and may also be a spectrophotometric type.

[0036] The measurement optical system 27 has an objective lens 21 and a beam splitter 24. The objective lens 21 is provided as an incident portion onto which light from the display is incident. The objective lens 21 is, for example, a plano-convex lens, and has a single positive power. The beam splitter 24 is provided as a light guiding portion that guides the light incident by the objective lens 21. The beam splitter 24 splits the beam that has passed through the objective lens 21 into three beams.

[0037] The beam splitting member 24 is disposed on the optical axis L of the light incident by the objective lens 21. Hereinafter, the "optical axis L of the light incident by the objective lens 21" will also be simply referred to as the "optical axis L of the objective lens 21." The beam splitting member 24 has an optical fiber 55 that propagates light, and lenses 56p, 56q, and 56r having positive power.

[0038] The optical fiber 55 is formed by bundling a plurality of optical fibers. The bundled optical fibers are split into three at a midpoint, resulting in the optical fiber 55 having one light beam incident surface A and three light beam exit surfaces B1, B2, and B3. The optical fiber 55 is disposed such that the light beam incident surface A is located at a position separated from the image-side principal point PP of the objective lens 21 by the focal length f of the objective lens 21. In other words, the objective lens 21 and the optical fiber 55 form a telecentric optical system. For ease of explanation, this embodiment illustrates an example in which the image-side principal point substantially coincides with the object-side principal point.

[0039] In this embodiment, the optical fiber 55 is used as the light beam splitting member 24, but the configuration is not limited to this. For example, the light beam splitting member 24 may be another optical component that performs the same function as the optical fiber, such as an optical guide tube.

[0040] The optical measurement device 1 is placed a predetermined distance away from the display surface 12 of the display. At this time, of the light beams emitted from each portion of the measurement area AR of the display, only the light beams having an emission angle equal to or smaller than the maximum value α relative to the normal direction of the measurement area AR are incident on the light beam incident surface A of the optical fiber 55. Note that the normal direction of the measurement area AR is the direction parallel to the optical axis L in FIG. 5 , which will be described later. Hereinafter, the maximum emission angle α will also be referred to as the "maximum emission angle α." The maximum emission angle α is determined by the focal length f of the objective lens 21 and the diameter R of the optical fiber 55 at the light beam incident surface A. The incident light beam is split into three light beams within the optical fiber 55, and each is emitted from the light beam emission surfaces B1, B2, and B3, respectively.

[0041] Each optical fiber that makes up the optical fiber 55 has a two-layer structure consisting of a core located in the center and a cladding that surrounds the core. The core is designed to have a higher refractive index than the cladding, so light propagates while being confined within the core by total internal reflection.

[0042] The light receiving system 28 has a photoelectric conversion unit 25 and an integrating unit 26. The photoelectric conversion unit 25 receives the light guided through the beam splitter 24 and converts it into an electrical signal.

[0043] 4, the photoelectric conversion unit 25 has first light-receiving sensors 62p, 62q, and 62r that have the spectral sensitivity characteristics of a standard observer. The first light-receiving sensors 62p, 62q, and 62r receive the three light beams emitted from the beam splitter 24, and photoelectrically convert the received light beams into electrical signals corresponding to the incident intensities and output the electrical signals. The integrating unit 26 integrates the electrical signals output from the first light-receiving sensors 62p, 62q, and 62r.

[0044] 4 and 5, the lens 56p focuses the light beam emitted from the light beam emission surface B1 of the optical fiber 55 onto the first light-receiving sensor 62p, and causes the light beam irradiation area LA to substantially coincide with the light-receiving area SA of the first light-receiving sensor 62p.

[0045] Similarly, the lens 56q focuses the light beam emitted from the light beam emission surface B2 of the optical fiber 55 onto the first light-receiving sensor 62q, and the irradiation range of the light beam approximately coincides with the light-receiving range of the first light-receiving sensor 62q. The lens 56r focuses the light beam emitted from the light beam emission surface B3 of the optical fiber 55 onto the first light-receiving sensor 62r, and the irradiation range of the light beam approximately coincides with the light-receiving range of the first light-receiving sensor 62r.

[0046] In this way, the light beam emitted from the optical fiber 55 is focused within the light-receiving ranges of the first light-receiving sensors 62p, 62q, and 62r. ​​One-third of the light beam incident on the optical fiber 55 is incident on each of the first light-receiving sensors 62p, 62q, and 62r. ​​Note that the light beam here refers to all light beams emitted from each portion of the measurement area AR of the display at an angle equal to or smaller than the maximum emission angle α with respect to the normal direction of the measurement area AR. This prevents a decrease in the amount of light received by the first light-receiving sensors 62p, 62q, and 62r.

[0047] 4, the first light-receiving sensors 62p, 62q, and 62r of the photoelectric conversion unit 25 further include spectral sensitivity correction filters 61p, 61q, and 61r, respectively. The spectral sensitivity correction filters 61p, 61q, and 61r are filters for providing the spectral sensitivity of the standard observer defined by the CIE.

[0048] The first light-receiving sensors 62p, 62q, and 62r include, for example, silicon photocells (SPCs) having substantially the same light-receiving sensitivity. The first light-receiving sensors 62p, 62q, and 62r are disposed on the optical axes of the lenses 56p, 56q, and 56r, respectively. The first light-receiving sensors 62p, 62q, and 62r are disposed at positions where the irradiation range of light collected by the lenses 56p, 56q, and 56r, respectively, is the light-receiving range of the first light-receiving sensors 62p, 62q, and 62r. ​​The spectral sensitivity compensation filters 61p, 61q, and 61r are disposed at appropriate positions between the first light-receiving sensors 62p, 62q, and 62r and the lenses 56p, 56q, and 56r, respectively.

[0049] The spectral sensitivity compensation filter 61p is sensitive to the R (red) wavelength region. Due to this filter characteristic, the first light-receiving sensor 62p is corrected to have a light-receiving sensitivity of a color-matching function (X bar lambda) that has high sensitivity in the red wavelength region. The spectral sensitivity compensation filter 61q is sensitive to the G (green) wavelength region. Due to this filter characteristic, the first light-receiving sensor 62q is corrected to have a light-receiving sensitivity of a color-matching function (W bar lambda) that has high sensitivity in the green wavelength region. The spectral sensitivity compensation filter 61r is sensitive to the B (blue) wavelength region. Due to this filter characteristic, the first light-receiving sensor 62r is corrected to have a light-receiving sensitivity of a color-matching function (Z bar lambda) that has high sensitivity in the blue wavelength region. The first light-receiving sensors 62p, 62q, and 62r each output light-receiving signals corresponding to tristimulus values ​​(X, Y, Z).

[0050] By simultaneously integrating the electrical signals output from each first light-receiving sensor using the integrating unit 26, the tristimulus value (X, Y, Z) signals can be converted into synchronous time-series signals. In other words, simultaneity can be ensured. Even if the integrating unit 26 does not ensure simultaneity, if the delay time of each signal is known in advance, the simultaneity of each signal can be ensured by correcting the time difference between the signals of the stimulus values ​​that are finally output. In other words, if the time difference between the signals of the stimulus values ​​that are finally output can be corrected, each signal can be considered to be a synchronous time-series signal. Note that the signals here may be measurement data or superimposed stimulus value data. Details of each data will be described later.

[0051] Although the measurement method using direct tristimulus value reading has been described above, in this embodiment, tristimulus values ​​may also be measured using spectrophotometric colorimetry. Fig. 6 is a diagram showing a specific configuration for measurement using spectrophotometric colorimetry. However, the configuration of this embodiment is not limited to this.

[0052] The objective lens 21, the beam splitter 24, and the photoelectric conversion unit 25 described above can be replaced with the configuration shown in Fig. 6. The configuration shown in Fig. 6 includes an objective lens unit 110, a light-guiding member 130, a polychromator 401, etc. The objective lens unit 110 and the light-guiding member 130 guide light emitted from the display surface 12 of the display to an entrance slit 400 of the polychromator 401. The light-guiding member 130 is disposed on the optical axis L of the light incident by the objective lens unit 110.

[0053] The polychromator 401 constitutes a spectroscopic optical system and includes an entrance slit 400, an imaging optical system (a collimator lens 410 and an imaging lens 440), a spectrometer (a grating 420), and a second light receiving sensor 430.

[0054] An entrance slit 400 is provided on the side wall of the polychromator 401. When light is introduced into the polychromator 401 through the entrance slit 400, a collimating lens 410 converts the introduced light into parallel light and guides it to a grating 420. The grating 420 disperses and reflects the light according to its wavelength. An imaging lens 440 forms an image dispersed by the grating 420 on the light-receiving surface of a second light-receiving sensor 430. The second light-receiving sensor has a plurality of pixels and converts information of the image formed on the light-receiving surface into an electrical signal.

[0055] The integrating unit 26 simultaneously integrates the measurement signals output from the light receiving sensors 430, thereby outputting a synchronous time series signal from the integrating unit 26. As described above, the simultaneity of the signals may be ensured by correcting the time difference. The A / D converting unit 31 converts the analog signal input from the integrating unit 26 into a digital signal.

[0056] Next, a description will be given of the details of the optical measurement device 1 other than the measurement unit 2. In addition to the measurement unit 2, the optical measurement device 1 has a storage unit 32, a control unit , a power supply unit 37, and a communication unit .

[0057] The memory unit 32 stores the digital signal output from the A / D conversion unit 31. The control unit 36 ​​controls the measurement operation by centrally controlling the operation of each unit in the optical measurement device 1. The control unit 36 ​​uses the measurement data stored in the memory unit 32 to calculate tristimulus values ​​(X, Y, Z), xyY (chromaticity coordinates, luminance) established by CIE, and the like.

[0058] The power supply unit 37 transforms the voltage of the power supplied from an external AC adapter (not shown) and supplies the power to each component via the control unit 36. The communication unit 38 outputs the calculation results of the control unit 36 ​​to the outside. The output calculation results are displayed in the form of a data list, graph, etc. on a personal computer (not shown) or the like. In addition, various information related to the measurement is input from the personal computer via the communication unit 38. Examples of the various information include measurement instructions, display mode settings, measurement range, etc.

[0059] [Mechanism of Occurrence of Color Shift and Flicker] The mechanism of occurrence of color change (color shift) and flicker when switching frames in an organic light emitting diode (OLED) display using RGB as a light source will be described.

[0060] In an OLED display using R (red), G (green), and B (blue) as light sources, the brightness L of each color OLED is calculated as shown in the following formula: Ｘ is the current I flowing through the OLED of each color Ｘ The subscript X represents either R, G, or B, and R, G, and B correspond to RED, GREEN, and BLUE, respectively. (Formula) L Ｘ ∝I Ｘ

[0061] The colors displayed on the OLED display depend on the brightness L of each OLED. Ｒ , L Ｇ , L Ｂ , i.e., the current I flowing through each color OLED. Ｒ , I Ｇ , I Ｂ If the current ratio is constant, the displayed color will not change.

[0062] The current flowing through the OLED satisfies the relationship of the following formula: Ｘ ×ΔT Ｘ =C Ｘ ×V Ｘ where each symbol is as follows: ΔT Ｘ : Rise time, for details, see I Ｘ Time from 0 to steady state. Ｘ : OLED capacitance. V Ｘ : Voltage across the OLED.

[0063] Since the dielectric constant and film thickness of OLEDs differ depending on the color, the capacitance C Ｘ The value of each color is different. Also, depending on the color you want to display, the current I Ｘ Therefore, the current I Ｘ The time ΔT until the steady state is reached differs for each color of the OLED and also differs depending on the color desired to be displayed on the display.

[0064] FIG. 7 shows the relationship between the light emission time T and the current I Ｘ 1 is a graph showing the relationship between current I Ｒ , I Ｇ , I Ｂ The time it takes for each to reach a steady state is ΔT Ｒ , ΔT Ｇ , ΔT Ｂ and the current I Ｒ , I Ｇ , I Ｂ The time it takes for everything to reach a steady state is ΔT ｍａｘ Also, from 0 to ΔT ｍａｘ This time is called the "transient state."

[0065] Transient state and ΔT ｍａｘ The steady state below is the current I Ｒ , I Ｇ , I Ｂ Therefore, the color displayed on the OLED display in the transient state differs from the color displayed on the OLED display in the steady state, resulting in a color shift.

[0066] In particular, in recent years, OLED displays that support low power consumption have been developed, reducing the current flowing through the OLED display. As the current decreases, the duration of the transient state becomes longer, which increases the time during which color shift occurs.

[0067] OLED displays also update images at the cycle of a vertical synchronizing signal (Vsync), which allows the frame rate and the refresh rate of the display to be synchronized, resulting in a stable screen display.

[0068] "Refresh rate" refers to the number of times a display draws an image per second, i.e., the rewriting frequency. A high refresh rate allows for smoother images to be displayed. A low refresh rate, i.e., driving or switching the display at a low frequency, reduces power consumption. On the other hand, a low refresh rate means that the flicker that occurs when switching images is easily noticeable to the human eye.

[0069] However, since the human eye has frequency characteristics, it is not necessarily possible to perceive all of the above-mentioned color shifts and flickers. Generally, the human eye has a generally flat sensitivity characteristic at frequencies below 10 Hz, but the sensitivity characteristic drops sharply above 10 Hz. In particular, the human eye does not have a sensitivity characteristic at 60 Hz, which is the refresh rate of a typical OLED display. In other words, when viewing a display that repeatedly turns on and off at 10 Hz, the human eye can perceive light, darkness, light, darkness, so it appears to be a flashing light source. On the other hand, when viewing a display that repeatedly turns on and off at 60 Hz, the human eye cannot perceive light, darkness, light, darkness, so it appears to be a steady light source that is darker than the bright state.

[0070] Therefore, a method is known in which a temporal contrast sensitivity function (TCSF) is superimposed on the acquired continuous stimulus value of an OLED display to derive a stimulus value that takes into account the visual stimulus response.

[0071] FIG. 8 shows the relationship between the light emission time T and the current I when an OLED display having a transient state is driven at a refresh rate of 10 Hz. Ｘ 9 is a graph showing the relationship between the light emission time T and the current I Ｘ 10 is a graph showing the relationship between the light emission time T and the current I when an OLED display having a transient state is driven at a refresh rate of 60 Hz. Ｘ 11 is a graph showing the relationship between the light emission time T and the current I Ｘ 9 and 11 are graphs showing the relationship between the value obtained by superimposing the temporal contrast sensitivity function (TCSF) on the luminance of the OLED of each color. That is, the graphs shown in Figures 9 and 11 are graphs that visualize the change in brightness of the OLED of each color as perceived by the human eye.

[0072] When driven at a refresh rate of 10 Hz, as shown in FIG. 9, the brightness of the OLED of each color as perceived by the human eye varies during the transient period ΔT ｍａｘ When driven at a refresh rate of 10 Hz, the transient state section ΔT ｍａｘ This is repeated within the range of the human eye's response, and as a result, the human eye can perceive a color that is different from the color displayed in the steady state (color shift).

[0073] When driven at a refresh rate of 60 Hz, the brightness of the OLEDs of each color perceived by the human eye does not change, as shown in Figure 11. When driven at a refresh rate of 60 Hz, the transient state section ΔT ｍａｘ This is repeated at a speed that exceeds the range of human eye response, so the human eye cannot perceive the repeated display of a color that is different from the color displayed in a steady state (color shift), and perceives it as continuous steady light.

[0074] Therefore, by quantifying and visualizing the change in brightness of the OLEDs of each color that is perceived by the human eye, that is, the change in color, it is possible to measure the color shift that is perceived by the human eye.

[0075] [Operation of Optical Measurement Device 1] The operation of the optical measurement device 1 of this embodiment will be described. Below, a method for measuring the color of a self-luminous color display that emits multiple colors independently as the measurement object and evaluating the measured color will be described. The measurement object does not necessarily have to be a self-luminous color display that emits multiple colors independently.

[0076] 12 is a flowchart showing the operation of the optical measurement device 1 of this embodiment. When measurement is started in the optical measurement device 1, the following operations are executed.

[0077] First, the control unit 36 ​​instructs the measurement object to set the light emission conditions for measurement (step S1: setting process). If the optical measurement device 1 of this embodiment is not connected to the measurement object, the measurer may operate the measurement object and set the light emission conditions for measurement. It is preferable to set a specific calibration image as the light emission conditions for measurement. For example, the light emission conditions are set to a display color of white (a mixture of RGB) and a refresh rate of 10 Hz and 60 Hz.

[0078] Next, the control unit 36 ​​instructs the measurement unit 2 to start measuring the stimulus value of the object (step S2: measurement step). The measurement unit 2 measures the light from the object under test at a sampling rate of 500 Hz or higher. This allows accurate sampling at a frequency higher than twice the bandwidth of the frequency components of the waveform, even for displays with a high refresh rate such as a vertical synchronization frequency (Vsync) of 240 Hz, i.e., a high-speed control display.

[0079] There are two main methods for acquiring light intensity: the sequential acquisition method, which acquires instantaneous values, and the integral acquisition method, which acquires integral values ​​over a set period of time. The sequential acquisition method excels in high speed, while the integral acquisition method excels in low-luminance measurement performance.

[0080] In this embodiment, measurement is performed by the measurement unit 2 using an integral method. The integral method has an excellent S / N (signal / noise ratio) and can improve measurement accuracy, but it cannot acquire measurement values ​​as quickly as the sequential method. However, this is not a problem in this embodiment for the reasons described below. Furthermore, when measuring luminance and chromaticity in addition to flicker measurement, the integral method is more suitable than the sequential method.

[0081] The integration method allows the integration time to be set arbitrarily within a certain range. In cases where high-speed sampling is not necessary but a certain degree of speed is required, such as in flicker measurement, the integration time is set as short as possible. In this embodiment, the integration time is set to, for example, 1.5 kHz. In cases where measurements are performed in synchronization with the frame rate of the object being measured, such as when accurately measuring luminance and chromaticity, the integration time may be set to, for example, approximately 60 Hz.

[0082] The control unit 36 ​​may also instruct the integrating unit 26 to simultaneously integrate the electrical signals output from the first light-receiving sensors 62p, 62q, and 62r. ​​The control unit 36 ​​may also instruct the integrating unit 26 to simultaneously integrate the electrical signals output from the second light-receiving sensor 430. This allows the acquired measurement signals to be synchronized time-series measurement signals. However, if the time lag of the measurement data calculated by the calculation unit can be corrected based on the delay time of each measurement signal, the integrating unit 26 does not necessarily have to simultaneously integrate the measurement signals.

[0083] The control unit 36 ​​instructs the A / D conversion unit 31 (the output unit of the measurement unit 2) to convert the analog signal into a digital signal. The control unit 36 ​​may also instruct the storage unit 32 to store the digital signal output from the A / D conversion unit 31.

[0084] <Necessity of high-speed sampling> The temporal contrast sensitivity function (TCSF), which represents the frequency characteristics of the eye, has almost no sensitivity in the high-frequency range. Therefore, even if the emission waveform of the measurement object is high-speed or high-frequency, in flicker measurement, high speed enough to faithfully acquire the emission waveform (shape) is not required.

[0085] Considering the load in the processes described below, it is preferable to have a small number of measurements, and the measurement acquisition speed does not need to be faster than necessary. Furthermore, unnecessary speeding up can lead to a decrease in the amount of incident light or an increase in circuit noise, which can cause a deterioration in the S / N (signal / noise ratio) and impair measurement accuracy.

[0086] An example of a measurement value acquisition speed is shown below. In recent years, high-speed control displays with a vertical synchronization frequency (Vsync) of 240 Hz or the like have been released. If these are driven by PWM (Pulse Width Modulation), high-speed data acquisition of at least 24 kHz (100 data points per cycle) is required to accurately acquire the waveform (shape). Furthermore, for a conventional display with a vertical synchronization frequency (Vsync) of 60 Hz, high-speed measurement value acquisition of at least 6 kHz is required. However, from the above perspective, when generating superimposed stimulus value data or measuring flicker, a speed of 6 kHz or less is not a problem and is in fact preferable.

[0087] In this embodiment, in view of the above, the measurement values ​​are acquired at 1.5 kHz. The measurement value acquisition speed may be changed according to the drive conditions of the object to be measured. For example, if the drive conditions are amplitude modulation drive, the measurement value acquisition speed may be slow, and if the drive conditions are PWM modulation drive, the measurement value acquisition speed may be fast.

[0088] When measurement values ​​are acquired at high speeds exceeding 6 kHz using the sequential acquisition method, they may be processed directly, or may be thinned out or averaged to reduce the number of measurement values ​​to be handled.

[0089] As described above, the measurement method may be a spectrophotometric method, in which the stimulus value is obtained by integrating the measurement signal for each wavelength acquired by the measurement unit 2 and the spectral sensitivity of the standard observer specified by the CIE in the integrator 26.

[0090] Next, the storage unit 32 and the control unit 36 ​​calculate, from the digital signals converted by the A / D conversion unit 31, synchronizable time-series color signals corresponding to the measurement signals for the X, Y, and Z components of the XYZ color system (step S3: calculation step). At this time, the storage unit 32 and the control unit 36 ​​function as a calculation unit. Note that the calculation step may be performed simultaneously with or after a digital filtering process step or a flicker index value derivation step, which will be described below.

[0091] In the measurement process, measurement signals are continuously acquired at regular time intervals, and in the calculation process, the measurement signals are converted into continuous data (measurement data) of stimulus value intensities. The converted stimulus values ​​include, for example, luminance, chromaticity (xy), and tristimulus values ​​represented by XYZ.

[0092] In converting the data into measurement data, a filter process may be performed to remove noise. For example, a moving average process using previous and next data may be applied.

[0093] In this way, the color of the measurement object can be measured. Furthermore, when evaluating color shift and flicker from the obtained measurement data, the following operations may be performed. The following operations may be performed by the control unit 36 ​​installed in the optical measurement device 1, or may be performed by the control unit 36 ​​in a personal computer connected to the optical measurement device 1. When performed by a personal computer, the measurement data stored in the memory unit 32 is sent from the communication unit 38 to the personal computer.

[0094] Next, the control unit 36 ​​reads out the frequency characteristics required for the filter processing from the storage unit 32 (step S4: reading step). At this time, the control unit 36 ​​functions as a reading unit. Next, the control unit 36 ​​converts the read frequency characteristics into impulse response characteristics (step S5: converting step). At this time, the control unit 36 ​​functions as a converting unit.

[0095] Frequency filtering is a method for revealing the characteristics of an acquired waveform. Frequency filtering assigns a desired weight to each frequency component that makes up the acquired waveform. For example, a low-pass filter (LPF) attenuates high frequencies relative to the signal frequency. This reduces high-frequency noise and reproduces a smooth signal waveform. As another example, when a temporal contrast sensitivity function (TCSF) is used as a filter, a waveform corresponding to a visual stimulus response can be reproduced.

[0096] The characteristics of the eye have been widely studied, and many temporal contrast sensitivity functions (TCSFs) have been reported for temporal responses. For example, in the literature "De Lange, H. Journal of the Optical Society of America, 1958, 48, 777-785," differences for each brightness are explained.

[0097] The TCSF used in the IEC standard and the like expresses only sensitivity data of the eye's frequency characteristics, as shown in FIG. 13 . However, to ensure accurate conversion to impulse response characteristics, it is desirable that the frequency characteristics include phase data. For this reason, in this embodiment, frequency characteristics including phase characteristics are stored in the storage unit 32. In this embodiment, for example, the TCSF described in IDMS version 1.03 Section 10.6 [published by the International Committee for Display Metrology (ICDM)] is stored in the storage unit 32.

[0098] FIG. 14 is a diagram showing an example of the frequency characteristics of the eye, including phase characteristics. The visual stimulus response, which is a sensory characteristic, is highly dependent on the individual (person), the environment, and the object being measured. For this reason, the storage unit 32 may store multiple frequency characteristics of the eye, and different frequency characteristics may be used depending on the conditions. Furthermore, the user may register the frequency characteristics of the eye and store them in the storage unit 32, or any frequency characteristic may be automatically selected. The frequency characteristics may be stored in an external device, such as a personal computer, connected to the optical measurement device 1.

[0099] Examples of parameters on which the visual stimulus response depends include the measurement area of ​​the measurement unit 2, luminance, color, gender, age, ambient luminance, and individual. For example, when using color as a parameter, automatic selection can be achieved by utilizing the stimulus value acquired in the measurement process. As another example, a sensor may be provided in the optical measurement device 1 to automatically switch between colors.

[0100] The control unit 36 ​​reads out necessary frequency characteristics from the stored frequency characteristics, and converts the read frequency characteristics into impulse response characteristics corresponding to visual stimulus responses by performing an inverse Fourier transform on the frequency characteristics.

[0101] 15 shows an example of an impulse response characteristic corresponding to a visual stimulus response. The response period to be stored is sufficient if it is long enough for the eye response to converge. The eye response generally converges after 0.5 seconds.

[0102] Next, the control unit 36 ​​performs digital filtering of the impulse response characteristics on the obtained measurement data (step S6: digital filtering step). At this time, the control unit 36 ​​functions as a digital filtering unit.

[0103] The digital filter processing is executed by a processor such as a central processing unit (CPU) provided in the optical measurement device 1 operating in accordance with an operation program. The operation program is stored in a read-only memory (ROM) or the like and is read by a random access memory (RAM). The CPU, ROM, and RAM function as the control unit 36.

[0104] The control unit 36 ​​performs digital filtering on the measurement data using impulse response characteristics to generate data on which a visual stimulus response is superimposed. Hereinafter, the data on which a visual stimulus response is superimposed will also be referred to as "superimposed stimulus value data."

[0105] Digital filter processing requires measurement data for at least the impulse response period. The superimposed stimulus value data generated begins after the response period, and the period before that is invalid due to missing data. To reduce this missing data period, in one example of this embodiment, the impulse response period is set to 0.5 seconds or less, which is the time required for the eye response to converge. Digital filter processing is performed using only the response portion of this 0.5 seconds or less.

[0106] The timing of the digital filter processing is not limited. The digital filter processing may be performed after acquisition of all measurement data, i.e., all data of consecutive stimulus values, has been completed, or the acquired stimulus values ​​may be processed sequentially even if acquisition of all data has not been completed.

[0107] Next, the control unit 36 ​​derives a flicker index value using the superimposed stimulus value data (step S7: flicker index value derivation step), and ends the operation. At this time, the control unit 36 ​​functions as a flicker index derivation unit.

[0108] The control unit 36 ​​derives a flicker index value using the superimposed stimulus value data obtained by the digital filter processing. This derivation is also performed by a processor such as a CPU operating in accordance with an operating program.

[0109] An example of how to derive the flicker index value is given below.

[0110] When the intensity of the flicker is static, such as when the light emission waveform is a periodic waveform, it is preferable to derive an index value calculated by the following formula for the entire time range of the superimposed stimulus value data: Index value = {maximum value (Max) - minimum value (Min)} / average value (Ave)

[0111] Furthermore, if the time range for deriving the index value can be set to a synchronous condition, i.e., an integer multiple of the light emission period, measurement errors can be reduced. Methods for setting the synchronous condition include, but are not limited to, using an external synchronization signal or having the user input a synchronization frequency.

[0112] In a variable refresh rate (VRR) display, the Vynsc frequency may be randomly switched. For example, in a mobile device, to save power, a low-speed drive may be used when displaying still images, and a high-speed drive (60 kHz) may be used when displaying moving images or when the screen is touched. When the flicker intensity fluctuates in this way, it is preferable to generate superimposed stimulus value data representing the time change in the flicker intensity.

[0113] Specifically, the index value is derived for each time interval for the superimposed stimulus value data, and a time variation of the index value is generated. By using this time variation data, it is possible to easily observe the extent to which the flicker intensity varies under certain circumstances. Note that the time interval is preferably an integer multiple of the Vynsc period.

[0114] 16 to 21 show the measurement results of the light emission waveform modeled on a variable refresh rate (VRR) display as the measurement target. FIG. 16 is a graph showing continuous data of stimulus intensity acquired for the display. The drive frequency of this display changes from 60 Hz to 24 Hz to 60 Hz, with no change in gradation. The frequency of the continuous data of stimulus intensity changes in accordance with the change in drive frequency.

[0115] Fig. 17 is an enlarged view of the time period around the timing when the drive frequency changes from 60 Hz to 24 Hz, and Fig. 18 is an enlarged view of the time period around the timing when the drive frequency changes from 24 Hz to 60 Hz.

[0116] 19 is a waveform diagram of the impulse response used in the digital filtering process. The impulse response period is 0.5 seconds or less.

[0117] 20 is a graph showing the superimposed stimulus value data obtained by digital filtering. It is clear that no waveform distortion occurs.

[0118] 21 is a graph showing the change in the flicker index value over time. The derivation time for the flicker index value is set to 12 Hz.

[0119] The method for deriving the flicker index value is not limited to the above method, and other methods of deriving the index value, such as a method of deriving the index value from an area ratio (Flicker Index by the IES method), may also be used.

[0120] In this way, the measurer can obtain data on the superimposed stimulus value and data on the time change of the flicker index value. Furthermore, from the obtained data, the measurer can evaluate color changes (color shifts) when flicker occurs, which is a non-steady state that can be perceived by the human eye.

[0121] In addition to the change in color when flicker occurs, for example, the change in chromaticity over time may be evaluated by providing a control value expressed by the following formula or the like.

[0122] In this embodiment, the digital signal output from the output section (A / D conversion section 31) of the measurement section 2 does not necessarily have to be continuous data. The method of acquiring the digital signal is not limited to the above method, and any conventionally known method may be used within the scope of the present invention. Conventionally known acquisition methods that can be used in this embodiment will be described below.

[0123] Conventional optical measurement devices acquire waveforms over a measurement period prepared in advance in the system, or the user inputs the number of measurement points and acquires a waveform for the time period corresponding to those points. A discrete Fourier transform (DFT) is performed on the acquired waveform to convert it into a frequency spectrum. The obtained frequency spectrum is then filtered with an arbitrary frequency characteristic. Specifically, weighting is performed by multiplying each frequency. The weighted frequency spectrum is then subjected to an inverse Fourier transform (IDFT) to acquire a filtered waveform.

[0124] However, in conventionally known discrete Fourier transform processing, waveform distortion may occur in some cases, so it is preferable to perform the processing under conditions that do not cause waveform distortion.

[0125] FIG. 22 shows an example of waveform distortion that can occur when using conventionally known discrete Fourier transform processing. The light waveform shown in (a) is acquired. At this time, as shown in (b-1), if the wave number is not an integer (4.5 periods in b-1), the synchronous measurement function is disabled. On the other hand, as shown in (b-2), if the wave number is an integer (4 periods in b-2), the synchronous measurement function is enabled. The resulting waveforms are weighted by frequency characteristics. In (c-1), distortion occurs at the leading and trailing ends of the waveform, but in (c-2), no distortion occurs in the waveform.

[0126] The fast Fourier transform is known as an algorithm that reduces the computational processing required for the discrete Fourier transform and the inverse Fourier transform. The fast Fourier transform is limited in that it can only handle data items that are a power of 2, i.e., the number of data items is 2d. Therefore, in order to reduce the computational load of the discrete Fourier transform and the inverse Fourier transform, it is preferable to set the number of measurement points when acquiring a waveform to a power of 2.

[0127] On the other hand, in the measurement data acquisition method described above, intensities corresponding to stimulus values ​​are continuously acquired at regular time intervals. This acquired continuous data of stimulus value intensities is then subjected to digital filtering using impulse response characteristics to generate data on which a visual stimulus response is superimposed. Therefore, while the generated superimposed stimulus value data is stimulus value data that takes into account the time response of the eye, it is not digitally Fourier transformed, so no waveform distortion occurs. This allows for accurate flicker measurement based on this superimposed stimulus value data. Furthermore, there is no need to remove part of the waveform to remove distortion, and measurement targets with non-periodic light-emitting waveforms can be accommodated.

[0128] Furthermore, in the past, as shown in FIG. 23 , superimposed stimulus value data and the like were derived only for stimulus value Y, and the measurer was unable to observe changes in color over time. However, in this embodiment, superimposed stimulus value data and the like can be derived by the control unit 36 ​​for stimulus values ​​X and Z, as well as chromaticity x and chromaticity y, in the same procedure as for stimulus value Y. These derivations can be instructed, for example, from the operation unit 39. The output superimposed stimulus value data and the like can then be displayed in the form of a graph on the display unit 40, as shown in FIG. 24 . This allows the measurer to observe changes in color over time. The operation unit 39 and the display unit 40 may be provided in a personal computer connected to the optical measurement device 1.

[0129] 23 and 24, the vertical axis represents the stimulus value, and the horizontal axis represents time. Original Date represents the measurement data before digital filtering. Weighted Date represents the superimposed stimulus value data after digital filtering.

[0130] Second Embodiment A color measurement system for measuring the colors of a self-luminous color display that emits multiple colors independently will be described. Fig. 25 is a block diagram showing the configuration of a color measurement system 100 of this embodiment. The color measurement system 100 is composed of an optical measurement device 1, a personal computer (PC) 43, and a color display 44.

[0131] The optical measurement device 1 includes a measurement unit 2, a control unit 36, and a communication unit 38. The measurement unit 2 includes a photoelectric conversion unit 25, an integrating unit 26, and an A / D conversion unit 31. The PC 43 includes a storage unit 32, an operation unit 39, a display unit 40, a PC control unit 41, and a PC communication unit 42. The color display 44 includes a light emitting unit 45, a display control unit 46, and a display communication unit 47.

[0132] In the second embodiment, a part of the configuration that the optical measurement device 1 in the first embodiment has is provided in the PC 43. Note that the configuration shown in Fig. 25 is an example, and the configurations that the optical measurement device 1, the PC 43, and the color display 44 each have are not limited to this.

[0133] An example of the operation of the color measurement system 100 will be described using the flowchart in Fig. 12. When measurement is started in the optical measurement device 1, the following operations are executed. Note that instructions between the optical measurement device 1, the PC 43, and the color display 44 are given via the communication unit 38, the PC communication unit 42, and the display communication unit 47. Details of each operation are the same as those described above.

[0134] The control unit 36 ​​or PC control unit 41 instructs the color display 44, which is the object of measurement, to set the light-emitting conditions for measurement (step S1: setting step). At this time, the control unit 36 ​​or PC control unit 41 functions as a light-emitting setting unit. Upon receiving the instruction, the display control unit 46 instructs the light-emitting unit 45 to set the light-emitting conditions for measurement. The measurer may set the light-emitting conditions for measurement using the operation unit 39.

[0135] Next, the control unit 36 ​​or PC control unit 41 instructs the measurement unit 2 to begin measuring the light from the color display 44 (step S2: measurement process). The measurement unit 2 measures the light from the color display 44 at a sampling rate of 500 Hz or higher. This allows accurate sampling at a frequency higher than twice the bandwidth of the frequency components of the waveform, even for displays with high refresh rates such as a vertical synchronization frequency (Vsync) of 240 Hz, i.e., high-speed control displays. The control unit 36 ​​instructs the A / D conversion unit 31 (output unit of the measurement unit 2) to convert the analog signal to a digital signal. The control unit 36 ​​or PC control unit 41 may also instruct the memory unit 32 to store the measurement data output from the A / D conversion unit 31.

[0136] Next, the storage unit 32 and the PC control unit 41 calculate, from the digital signals converted by the A / D conversion unit 31, synchronizable time-series color signals corresponding to the measurement signals for the X, Y, and Z components of the XYZ color system (step S3: calculation step). At this time, the storage unit 32 and the PC control unit 41 function as a calculation unit.

[0137] Next, the PC control unit 41 reads out the frequency characteristics required for the filter processing from the storage unit 32 (step S4: reading step). At this time, the PC control unit 41 functions as a reading unit. Next, the PC control unit 41 converts the read-out frequency characteristics into impulse response characteristics (step S5: converting step). At this time, the PC control unit 41 functions as a converting unit.

[0138] Next, the PC control unit 41 performs digital filtering of the impulse response characteristics on the obtained measurement data (step S6: digital filtering process). At this time, the PC control unit 41 functions as a digital filtering unit.

[0139] Next, the PC control unit 41 derives a flicker index value using the superimposed stimulus value data (step S7: flicker index value derivation step), and ends the operation. At this time, the PC control unit 41 functions as a flicker index derivation unit.

[0140] In this embodiment, the optical measurement device 1 includes a measurement unit 2 that measures light from an object to be measured at a sampling rate of 500 Hz or higher, and a calculation unit (a storage unit 32 and a control unit 36) that calculates synchronous time-series color signals corresponding to the measurement signals for each of the X, Y, and Z components of the XYZ color system. This makes it possible to suitably evaluate color shift in the case of a display that uses an RGB light source as its light source.

[0141] In this embodiment, the optical measurement device 1 performs color measurement on a self-luminous color display 12 that emits light of multiple colors independently. This makes it possible to suitably evaluate color misalignment in a display that uses an RGB light source.

[0142] In this embodiment, the measurement unit 2 includes a plurality of compensation filters 61p, 61q, 61r and a plurality of first light-receiving sensors 62p, 62q, 62r that receive light beams that pass through the plurality of compensation filters 61p, 61q, 61r, respectively, and the plurality of compensation filters 61p, 61q, 61r and the plurality of first light-receiving sensors 62p, 62q, 62r have spectral sensitivities corresponding to the X component, the Y component, and the Z component of the color matching function, respectively. This makes it possible to measure tristimulus values ​​using a tristimulus value direct reading measurement method.

[0143] In this embodiment, the measurement unit 2 includes a spectroscope (grating 420) and a second light-receiving sensor 430 having a plurality of pixels that receive light dispersed by the spectroscope. This makes it possible to measure tristimulus values ​​using spectrophotometric colorimetry as a measurement method.

[0144] In this embodiment, a digital filter processing unit (control unit 36) is provided that performs frequency filtering on the digital signal output from the output unit (A / D conversion unit 31) of the measurement unit 2. This makes it possible to reveal the characteristics of the acquired waveform.

[0145] In this embodiment, a storage unit 32 that stores frequency characteristics used in frequency filter processing and a readout unit (control unit 36) that reads out the frequency characteristics from the storage unit 32 are provided. This allows different frequency characteristics to be used depending on the conditions.

[0146] In this embodiment, a conversion section (control section 36) is provided that converts the read frequency characteristics into impulse response characteristics, thereby generating superimposed stimulus value data with the impulse response characteristics superimposed thereon.

[0147] In this embodiment, the frequency filtering process is a process using a temporal contrast sensitivity function, which allows for the generation of superimposed stimulus value data in which a visual stimulus response is superimposed.

[0148] In this embodiment, the temporal contrast sensitivity function is a sensitivity function based on the IDMS standard, which allows for the generation of superimposed stimulus value data in which a more accurate visual stimulus response is superimposed.

[0149] This embodiment includes a flicker index derivation unit (control unit 36) that derives a flicker index based on the digital signal output from the output unit (A / D conversion unit 31) of the measurement unit 2. This makes it possible to visualize the occurrence of flicker as shown in Fig. 21 .

[0150] In this embodiment, the color signals output from the calculation unit (the storage unit 32 and the control unit 36) are tristimulus value signals, which allow the color change at the time of frame transition to be visualized as a change in the numerical values ​​of the tristimulus values.

[0151] In this embodiment, the color signal output from the calculation unit (the storage unit 32 and the control unit 36) is a chromaticity signal, which allows a change in color at the time of frame switching to be visualized as a change in chromaticity value.

[0152] In this embodiment, the measurement unit 2 includes an integrating unit 26 that simultaneously integrates the measurement signals output from the first light-receiving sensors 62p, 62q, and 62r, thereby calculating a synchronous time-series color signal.

[0153] In this embodiment, the measurement unit 2 includes an integrating unit that simultaneously integrates the measurement signals output from the second light receiving sensors 430. This makes it possible to calculate a synchronous time-series color signal.

[0154] In addition, the detailed configuration and detailed operation of each device constituting the optical measurement device can be modified as appropriate within the scope of the present invention.

[0155] By using the present invention, color misregistration can be suitably evaluated in the case of a display using an RGB light source as the light source.

[0156] REFERENCE SIGNS LIST 1 Optical measurement device 2 Measurement unit 12 Display surface of display 21 Objective lens 24 Light beam splitter 25 Photoelectric conversion unit 26 Integration unit 27 Measurement optical system 28 Light receiving system 31 A / D conversion unit 32 Memory unit 37 Power supply unit 38 Communication unit 39 Operation unit 40 Display unit 41 PC control unit 42 PC communication unit 43 Personal computer (PC) 44 Color display 45 Light emitting unit 46 Display control unit 47 Display communication unit 55 Optical fiber 56p, 56q, 56r Lens 61p, 61q, 61r Spectral sensitivity compensation filter 62p, 62q, 62r First light receiving sensor 110 Objective lens unit 130 Light guiding member 400 Entrance slit 401 Polychromator 410 Collimating lens 420 Grating 430 Second light receiving sensor 440 Imaging lens

Claims

1. An optical measurement device comprising: a measurement unit that measures light from an object to be measured at a sampling rate of 500 Hz or more; and a calculation unit that calculates synchronous time-series color signals corresponding to the measurement signals for each of the X, Y, and Z components of the XYZ color system.

2. The optical measurement device according to claim 1, which measures the color of a self-luminous color display that emits light independently in multiple colors.

3. The optical measurement device according to claim 1 or 2, wherein the measurement unit comprises a plurality of compensation filters and a plurality of first light-receiving sensors that receive light beams that pass through the plurality of compensation filters, and the plurality of compensation filters and the plurality of first light-receiving sensors have spectral sensitivities corresponding to the X component, the Y component, and the Z component of the color-matching function, respectively.

4. An optical measurement device according to claim 1 or 2, wherein the measurement unit comprises: a spectroscope; and a second light-receiving sensor having a plurality of pixels that receives light dispersed by the spectroscope.

5. The optical measurement device according to claim 1 or 2, further comprising a digital filter processing section that performs frequency filtering on the digital signal output from the output section of said measurement section.

6. The optical measurement device according to claim 5, comprising: a storage unit that stores frequency characteristics used in said frequency filter processing; and a readout unit that reads out said frequency characteristics from said storage unit.

7. The optical measurement device according to claim 6, further comprising a conversion section that converts the read frequency characteristics into impulse response characteristics.

8. The optical measurement device of claim 5, wherein the frequency filtering is a processing using a temporal contrast sensitivity function.

9. The optical measurement device of claim 8, wherein the temporal contrast sensitivity function is a sensitivity function based on the IDMS standard.

10. The optical measurement device according to claim 5, further comprising a flicker index derivation unit that derives a flicker index based on the digital signal output from the output unit of said measurement unit.

11. An optical measurement device according to claim 1 or 2, wherein the color signal calculated by the calculation unit is a tristimulus value signal.

12. An optical measurement device according to claim 1 or 2, wherein the color signal calculated by the calculation unit is a chromaticity signal.

13. The optical measurement device according to claim 3, wherein the measurement section includes an integrating section that simultaneously integrates the measurement signal output from the first light receiving sensor.

14. The optical measurement device according to claim 4, wherein said measurement section includes an integrating section that simultaneously integrates the measurement signal output from said second light receiving sensor.

15. A color measurement system for measuring the colors of a self-luminous color display that emits multiple colors independently, comprising: an emission setting unit that sets the emission conditions of the self-luminous color display; a measurement unit that measures light from an object to be measured at a sampling rate of 500 Hz or more; and a calculation unit that calculates synchronous time-series color signals corresponding to the measurement signals of each of the X, Y, and Z components of an XYZ color system, wherein the measurement unit comprises multiple compensation filters and multiple first light-receiving sensors that receive light beams that pass through each of the multiple compensation filters, and the multiple compensation filters and the multiple first light-receiving sensors have spectral sensitivities corresponding to the X, Y, and Z components of a color matching function, respectively.

16. A method for evaluating the color of a self-luminous color display that emits multiple colors independently, comprising: a setting step for setting the light-emitting conditions of the self-luminous color display; a measurement step for measuring light from an object under measurement at a sampling rate of 500 Hz or more; a calculation step for calculating synchronous time-series color signals corresponding to the measurement signals for each of the X, Y, and Z components of the XYZ color system; and an evaluation step for comparing the steady state and non-steady state of the output time-series color signals to evaluate color changes at frame transitions.

17. A program that causes a computer in a color measurement system that measures the color of a self-luminous color display that emits multiple colors independently to execute the following: an emission setting process that sets the emission conditions of said self-luminous color display; a measurement process that measures light from an object to be measured at a sampling rate of 500 Hz or more; and an arithmetic process that calculates synchronous time-series color signals corresponding to the measurement signals for each of the X, Y, and Z components of the XYZ color system.

Images