Luminance measurement system, luminance measurement device, gamma adjustment system, luminance measurement method, gamma adjustment method, and program

Abstract

Provided are a luminance measurement system and the like in which the measurement time is shortened.　The luminance measurement system comprises an image generation unit, a measurement unit, and a control unit. The image generation unit generates an image signal corresponding to an image to be displayed on a display. The measurement unit measures the luminance of the image displayed on the display on the basis of the image signal. The control unit controls the image generation unit and the measurement unit on the basis of a plurality of measurement modes for sequentially executing luminance measurement at a plurality of different target luminances. The control unit sequentially and continuously executes a first measurement mode and a second measurement mode. At this time, in the first measurement mode, the target luminance is set from the target luminance of a low-luminance region to the target luminance of a high-luminance region having a higher luminance than the low-luminance region, and luminance measurement is executed. In the second measurement mode, the target luminance is set from the target luminance of the high-luminance region to the target luminance of the low-luminance region through the target luminance of an intermediate luminance region between the low-luminance region and the high-luminance region, and luminance measurement is executed.

Description

Brightness measurement system, brightness measurement device, gamma adjustment system, brightness measurement method, gamma adjustment method, and program

[0001] This disclosure relates to a luminance measurement system, a luminance measurement device, a gamma adjustment system, a luminance measurement method, a gamma adjustment method, and a program.

[0002] The gamma value of a display can be measured by measuring its brightness when it emits light. In the display inspection process, gamma adjustment is known, in which the gamma value is measured and adjusted to a desired gamma value for the input signal (Patent Document 1).

[0003] A color analyzer with multiple measurement ranges is known as a device for measuring the brightness of a display when it emits light. By using multiple measurement ranges according to the brightness of the display when it emits light, a color analyzer can measure the brightness of the display under optimal conditions.

[0004] Japanese Patent Publication No. 2009-244566

[0005] In recent years, the increased performance of displays has made gamma adjustment more complex. Consequently, the conditions for measuring brightness using color analyzers have also become more complex, increasing the time spent on measurements. Furthermore, gamma adjustment involves repeatedly performing measurements at both low and high brightness levels. In particular, when attempting to measure at low brightness after measuring at high brightness, slight residual charges remaining in the electronic circuits of the measuring device can cause slight errors in the light output value. This effect of residual charge is called luminescence residue. Due to the residual charge, a waiting time is required until the residue dissipates, further increasing the time spent on measurements.

[0006] The problem addressed by this disclosure is to provide a luminance measurement system, etc., that shortens the measurement time.

[0007] To solve the above problems, the luminance measurement system of the present disclosure comprises: an image generation unit that generates an image signal corresponding to an image to be displayed on a display; a measurement unit that measures the luminance of an image displayed on the display based on the image signal; and a control unit that controls the image generation unit and the measurement unit based on a plurality of measurement modes that sequentially perform luminance measurements at a plurality of different target luminances. When the control unit sequentially executes the first measurement mode and the second measurement mode, the first measurement mode sets the target luminance from the target luminance of a low-luminance region to the target luminance of a high-luminance region which is brighter than the low-luminance region and performs the luminance measurement. The second measurement mode sets the target luminance from the target luminance of the high-luminance region, through the target luminance of a medium-luminance region between the low-luminance region and the high-luminance region, to the target luminance of the low-luminance region and performs the luminance measurement.

[0008] The luminance measuring device of the present disclosure comprises: an image generation unit that generates an image signal corresponding to an image displayed on a display; a measurement unit that measures the luminance of an image displayed on the display based on the image signal; and a control unit that controls the image generation unit and the measurement unit based on a plurality of measurement modes that sequentially perform luminance measurements at a plurality of different target luminances, wherein the control unit, when sequentially executing a first measurement mode and a second measurement mode, performs the luminance measurement by setting the target luminance from the target luminance of a low-luminance region to the target luminance of a high-luminance region which is brighter than the low-luminance region; and performs the luminance measurement by setting the target luminance from the target luminance of the high-luminance region, through the target luminance of a medium-luminance region between the low-luminance region and the high-luminance region, to the target luminance of the low-luminance region.

[0009] The gamma adjustment system of this disclosure comprises the luminance measurement system and a gamma correction unit that changes the input / output conversion characteristics of the display based on a gamma value calculated from the measured luminance.

[0010] The luminance measurement method of the present disclosure is a luminance measurement method performed by a luminance measurement system, comprising: an image generation step of generating an image signal corresponding to an image to be displayed on a display; and a measurement step of measuring the luminance of an image displayed on the display based on the image signal, wherein the measurement step executes a plurality of measurement modes that sequentially perform luminance measurements at a plurality of different target luminances, and when the first measurement mode and the second measurement mode are executed in succession, the first measurement mode sets the target luminance from the target luminance of a low-luminance region to the target luminance of a high-luminance region which is brighter than the low-luminance region and performs the luminance measurement, and the second measurement mode sets the target luminance from the target luminance of the high-luminance region, through the target luminance of a medium-luminance region between the low-luminance region and the high-luminance region, to the target luminance of the low-luminance region and performs the luminance measurement.

[0011] The gamma adjustment method of this disclosure comprises a gamma measurement step of measuring luminance using the luminance measurement method and calculating a gamma value from the measured luminance, and a gamma correction step of changing the input / output conversion characteristics of the display based on the measured gamma value.

[0012] The program of the present disclosure causes a computer of a brightness measurement system, which comprises an image generation unit that generates an image signal corresponding to an image to be displayed on a display, a measurement unit that measures the brightness of an image displayed on the display based on the image signal, and a control unit that controls the image generation unit and the measurement unit based on a plurality of measurement modes that sequentially perform brightness measurements at a plurality of different target brightness levels, to execute a first measurement mode and a second measurement mode in sequence: The first measurement mode sets the target brightness from the target brightness of the low brightness region to the target brightness of the high brightness region which is brighter than the low brightness region and performs the brightness measurement; The second measurement mode sets the target brightness from the target brightness of the high brightness region, through the target brightness of the medium brightness region between the low brightness region and the high brightness region, to the target brightness of the low brightness region and performs the brightness measurement.

[0013] According to this disclosure, the time required for measuring brightness can be reduced.

[0014] This is a block diagram showing an example of the configuration of a luminance measurement system. This is a block diagram showing an example of the configuration of a tristimulus value direct reading type luminance measurement device. This is a flowchart showing an example of the process in a gamma adjustment method. This is a sequence diagram showing an example of the operation of the luminance measurement system and display in the gamma measurement process. This shows the relationship between measurement time and target luminance in an example shown in Table III. This shows the relationship between measurement time and target luminance in an example shown in Table IV.

[0015] 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.

[0016] [Configuration of the Brightness Measurement System] Figure 1 is a block diagram showing an example of the configuration of the brightness measurement system 100 in this embodiment. The brightness measurement system 100 includes a brightness measuring device 10 and a management device 30. In the brightness measurement system 100, the brightness measuring device 10 and the management device 30 may be an integrated device.

[0017] In this embodiment, the brightness on the display surface of the display 40 is measured using the brightness measurement system 100. The management device 30 may calculate the gamma value of the display 40 from the measured value. Furthermore, the management device 30 may change the input / output conversion characteristics of the display 40 based on the calculated gamma value and correct the gamma value. In this case, the second control unit 31 of the management device 30 functions as a gamma correction unit. In other words, the brightness measurement system 100 may be used as a gamma adjustment system. Note that other devices may be used to calculate and correct the gamma value.

[0018] (Configuration of the luminance measuring device) Figure 2 is a block diagram showing an example of the configuration of the tristimulus value direct reading type luminance measuring device 10 of this embodiment. However, the luminance measuring device of this embodiment is not limited to the tristimulus value direct reading type, but may also be a spectrophotometric type. In Figure 2, the luminance measuring device 10 measures the luminance of the display 1 when it emits light.

[0019] The luminance measuring device 10 comprises a measuring unit 16, a first display unit 17, a first operation unit 18, a first communication unit 19, and a first control unit 15. The measuring unit 16 comprises an objective optical system 11, a branching optical system 12, a colorimetric optical system 13, and an electrical processing unit 14.

[0020] The objective optical system 11 comprises a convex lens 11a with positive power, an optical attenuation filter 4 as an optical attenuation unit, and an aperture diaphragm 11b. The branching optical system 12 comprises a diffuser plate 20 that has branching and diffusion functions. The optical attenuation filter 4 is also called an "ND filter".

[0021] The aperture diaphragm 11b is positioned at the rear focal point of the convex lens 11a. By using a front-telecentric optical arrangement, components within ±2.5 degrees of the normal to the surface under test, which is the display surface of the display 1, can be captured. The diffuser plate 20 is positioned behind the surface of the aperture diaphragm 11b. The light attenuation filter 4 is positioned between the convex lens 11a and the diffuser plate 20, and is positioned in front of the surface of the aperture diaphragm 11b.

[0022] The light attenuation filter 4 is driven by an insertion / removal device 5, which acts as an insertion / removal mechanism. The insertion / removal device 5 inserts the light attenuation filter 4 into or removes it from the optical path of the light under test 2. The insertion / removal device 5 has, for example, a linear actuator. When the light attenuation filter 4 is inserted into the optical path of the light under test 2, the amount of light from the light under test 2 entering the diffuser plate 20 is reduced by the light attenuation filter 4. When the light attenuation filter 4 is removed from the optical path of the light under test 2, the light under test 2 enters the diffuser plate 20 without any reduction in light intensity.

[0023] The light attenuation filter 4 is inserted or removed depending on the brightness (luminance) of the display 1. Specifically, when the display 1 is dark, i.e., low luminance, the light attenuation filter 4 is removed from the optical path. When the display 1 is bright, i.e., high luminance, the light attenuation filter 4 is inserted into the optical path to reduce the amount of light, thereby preventing saturation of the light receiving sensors 132a, 132b, and 132c. This allows the intensity of the light under test 2 to be kept within the dynamic range of the light receiving sensors 132a, 132b, and 132c, and as a result, the dynamic range of the luminance measuring device 10 is expanded.

[0024] The colorimetric optical system 13 comprises color filters 131a, 131b, and 131c, and light receiving sensors 132a, 132b, and 132c. The color filters 131a, 131b, and 131c are wavelength filters and are color matching function filters corresponding to the tristimulus values ​​of X, Y, and Z, respectively. The light receiving sensors 132a, 132b, and 132c are light receiving elements used in combination with the color matching function filters.

[0025] For example, silicon sensors are used as the light receiving sensors 132a, 132b, and 132c. The light received by each light receiving sensor 132a, 132b, and 132c is converted into an electrical signal and input to the corresponding electrical processing units 14a, 14b, and 14c.

[0026] The electrical processing units 14a, 14b, and 14c perform I / V conversion, amplification, and other processing on the input electrical signal. The processed electrical signal is then input to the first control unit 15 as numerical data.

[0027] The first display unit 17 and the first operation unit 18 are equipped with, for example, a liquid crystal display (LCD) with a touch panel. The first display unit 17 displays various operation screens, measurement data, etc., according to signals input from the first control unit 15. The first operation unit 18 is equipped with various operation keys such as a numeric keypad and a start key, and accepts various input operations from the user and outputs signals to the first control unit 15.

[0028] The first communication unit 19 transmits and receives various signals or data to and from an external device based on the communication control of the first control unit 15.

[0029] The first control unit 15 includes a CPU, RAM, memory, etc. The CPU is a hardware processor that controls the operation of each part of the brightness measuring device 10 by reading various programs stored in memory, loading them into RAM, and executing various processes according to the loaded programs.

[0030] (Configuration of the control device) The control device 30 comprises a second display unit 32, a second operation unit 33, a second communication unit 34, and a second control unit 31.

[0031] The second display unit 32 and the second operation unit 33 are equipped with, for example, a liquid crystal display (LCD) with a touch panel. The second display unit 32 displays various operation screens, measurement data, etc., according to signals input from the second control unit 31. The second operation unit 33 is equipped with various operation keys such as a numeric keypad and a start key, and accepts various input operations from the user and outputs signals to the second control unit 31.

[0032] The second control unit 31 includes a CPU, RAM, memory, etc. The CPU is a hardware processor that controls the operation of each part of the management device 30 by reading various programs stored in memory, loading them into RAM, and executing various processes according to the loaded programs.

[0033] The second communication unit 34 transmits and receives various signals or data to an external device based on the communication control of the second control unit 31.

[0034] (Display Configuration) The display 40, which serves as the test subject for the brightness measurement system 100, comprises a light-emitting unit 42, a third communication unit 43, and a third control unit 41. The light-emitting unit 42 is equipped with a light-emitting element such as an organic electroluminescent (EL) element. The light-emitting unit 42 emits light based on instructions from the third control unit 41. The third communication unit 43 receives various signals or data from the second communication unit 34 of the management device 30 based on the communication control of the third control unit 41.

[0035] The display 40 may be an organic EL display (OLED), a liquid crystal display (LCD), or a microLED.

[0036] [Gamma Adjustment Method] The luminance measurement system 100 of this embodiment is used during gamma adjustment in the inspection process on the manufacturing line of the display 40.

[0037] In an apparatus that outputs image data such as a display, the "gamma value" refers to a numerical value indicating the response characteristics of the gradation of an image. Depending on the output device, the response characteristics of the gradation of an image differ, and each output device has its own gamma value. Therefore, correction is applied in advance to the input value (voltage, numerical value of digital data, etc.) input to the output device, taking into account the gamma value of the output device. This is called "gamma correction."

[0038] In order to perform gamma correction accurately, the display needs to be manufactured according to the set gamma value. The manufacturer measures the luminance value of the display in the inspection process. If there is a deviation between the measured value and the set value, the input / output conversion characteristics of the look-up table built into the display are changed, etc., to correct the gamma value. A series of operations in the measurement and correction of the gamma value is called "gamma adjustment."

[0039] That is, in the measurement of luminance in gamma adjustment, the display is made to emit light for a predetermined input signal, the luminance of the display surface is measured, and it is inspected whether the display is actually emitting light at a predetermined luminance (target luminance). By changing the target luminance to obtain a plurality of data and taking a plot, a gamma curve representing the relationship between the input value and the output value can be obtained.

[0040] FIG. 3 is a flowchart showing an example of the steps in the gamma adjustment method. When gamma adjustment is started, the following steps are executed. Here, although the steps other than the gamma measurement step are also executed by the management device 30, they may be executed by other devices.

[0041] First, the second control unit 31 of the management device 30 sets the display frequency for executing gamma adjustment (S11: display frequency setting step).

[0042] Next, the second control unit 31 instructs the luminance measurement device 10 and the display 40 via the second communication unit 34 to measure the emission luminance of the display 40 for a predetermined input signal at the set display frequency (S12: gamma measurement step).

[0043] Next, the second control unit 31 determines whether the measurement result meets a predetermined value (S13: gamma confirmation step). If the second control unit 31 determines that the measurement result meets the predetermined value (S13: YES), it terminates the series of operations. If the second control unit 31 determines that the measurement result does not meet the predetermined value (S13: NO), it proceeds to step S14.

[0044] Next, the second control unit 31 corrects the luminescence brightness of the display 40 for a predetermined input signal at a set display frequency based on the acquired measurement results (S14: gamma correction step). The luminescence brightness is corrected by, for example, adjusting the voltage applied to the electronic circuit inside the display 40. The method for correcting the luminescence brightness is not particularly limited, and known methods may be used. Thereafter, steps S12 to S14 are repeated, and the measurement, confirmation, and correction steps at a predetermined target brightness are repeated. Gamma correction is performed until the measurement result satisfies a predetermined value.

[0045] An upper limit may be set for the repetition of steps S12 to S14. If the measurement result does not meet the predetermined value even after reaching the upper limit, it is determined to be an abnormality. Once the correction is completed at the predetermined target brightness, the target brightness is then changed sequentially, and steps S12 to S14 are repeated, repeating the measurement, confirmation, and correction process at the target brightness.

[0046] When performing gamma adjustment for multiple display frequencies, for example, three display frequencies of 30 Hz, 60 Hz, and 90 Hz, steps S11 to S14 are repeated for each display frequency. In this example, the display frequency is set in step S11, but multiple types of gradation and adjustment points may also be set, and steps S11 to S14 may be repeated for each setting.

[0047] (Gamma measurement) The detailed operation of the gamma measurement process S12 will be explained below.

[0048] Figure 4 is a sequence diagram showing an example of the operation of the luminance measurement system 100 and the display 40 in the gamma measurement process. When the gamma measurement process S12 is started, the following operations are performed. In the gamma measurement process S12, all processes except the gamma calculation process S28 correspond to the processes in luminance measurement.

[0049] First, the second control unit 31 of the management device 30 acquires the gamma measurement conditions (S21: Gamma measurement condition acquisition step). If the memory of the second control unit 31 stores gamma measurement conditions, the second control unit 31 reads the stored gamma measurement conditions. The second control unit 31 may acquire gamma measurement conditions input by the user from the second operation unit 33 of the management device 30, or it may acquire gamma measurement conditions from other devices via the second communication unit 34.

[0050] Next, the second control unit 31 of the control device 30 sets the output value of the display 40 based on the target brightness for each measurement step under the acquired gamma measurement conditions (S22: output value setting step).

[0051] Next, the second control unit 31 of the management device 30 sets the image to be displayed on the display 40 based on the set output value and generates an image signal corresponding to the image (S23: image generation process). At this time, the second control unit 31 functions as an image generation unit. The luminance measurement system 100 may also be equipped with a separate image generator (not shown) that creates the image signal, and the second control unit 31 may control the image generator.

[0052] Next, the second control unit 31 of the management device 30 sorts the multiple measurement modes in descending order of maximum target brightness for each measurement mode based on the acquired gamma measurement conditions and sets the execution order (S24: Measurement mode execution order setting step). This step is not necessarily required, but performing it will allow for more efficient measurement. Details of the setting will be described later. Note that if the execution order of multiple measurement modes has already been set in descending order of maximum target brightness based on the acquired gamma measurement conditions, sorting is not required.

[0053] Next, the second control unit 31 of the management device 30 rearranges the measurement steps within the measurement mode to minimize waiting time under the gamma measurement conditions and sets the execution order (S25: measurement step execution order setting step). This minimizes waiting time during brightness measurement and shortens the measurement time. Details of the setting will be described later. Note that if the execution order of the measurement steps has already been set to minimize waiting time under the acquired gamma measurement conditions, rearrangement is not necessary.

[0054] Next, the second control unit 31 of the management device 30 instructs the second communication unit 34 to transmit the gamma measurement conditions to the display 40 and the brightness measuring device 10 (S26: Gamma measurement condition transmission step). The gamma measurement conditions here include the generated image signal and are set in the execution order in which the measurement steps are rearranged. In addition, the insertion / removal state of the optical attenuation filter 4 may be set for each measurement step according to the target brightness.

[0055] Next, the third control unit 41 of the display 40 instructs the third communication unit 43 to receive the gamma measurement conditions transmitted from the second communication unit 34 of the management device 30 (S31: First gamma measurement condition reception step).

[0056] Next, the third control unit 41 of the display 40 instructs the light-emitting unit 42 to start emitting light based on the received image signal of the gamma measurement conditions (S32: light emission start step).

[0057] Next, the first control unit 15 of the luminance measuring device 10 instructs the first communication unit 19 to receive the gamma measurement conditions transmitted from the second communication unit 34 of the management device 30 (S41: Second gamma measurement condition reception step).

[0058] Next, the first control unit 15 of the luminance measuring device 10 sets the measurement conditions of the luminance measuring device 10 based on the target luminance for each measurement step in the received gamma measurement conditions (S42: measurement condition setting step).

[0059] Next, the first control unit 15 of the luminance measuring device 10 instructs the measuring unit 16 to adjust to meet the measurement conditions (S43: measurement condition adjustment step). Specifically, the adjustment step includes inserting and removing the light attenuation filter 4, refreshing the electronic circuit to remove residue, and so on.

[0060] Next, the first control unit 15 of the brightness measuring device 10 instructs the measurement unit 16 to measure the brightness of the display 40 after confirming that the adjustment of the measurement conditions is complete (S44: measurement process).

[0061] Next, the first control unit 15 of the luminance measuring device 10 instructs the first communication unit 19 to transmit the measurement history (S45: measurement history transmission step), and terminates the operation of the luminance measuring device 10.

[0062] Next, the second control unit 31 of the management device 30 instructs the second communication unit 34 to receive the measurement history transmitted from the first communication unit 19 of the brightness measuring device 10 (S27: measurement history reception step). Once the measurement history is received, the second control unit 31 instructs the third control unit 41 of the display 40 to stop the illumination of the display 40 via the second communication unit 34 and the third communication unit 43.

[0063] Next, the third control unit 41 of the display 40 instructs the light-emitting unit 42 to terminate the light emission (S33: light emission termination process), thereby ending the operation of the display 40.

[0064] Finally, the second control unit 31 of the control device 30 calculates the gamma value from the measured values ​​included in the received measurement history (S28: gamma calculation step) and terminates the operation of the control device 30.

[0065] When measuring luminance in multiple gradations, repeat the above process for each gradation. When measuring luminance at multiple adjustment points, repeat the above process for each adjustment point.

[0066] The following describes the details of the gamma measurement conditions.

[0067] The gamma value can be calculated by measuring the brightness of the display 40 based on gamma measurement conditions and taking the measured values. The gamma measurement conditions have multiple measurement modes, and one gamma curve can be obtained from one measurement mode. Each measurement mode has multiple measurement steps with different target brightness values ​​set.

[0068] Within a single measurement mode, all conditions except the target brightness remain unchanged, and the display brightness is measured multiple times by changing only the target brightness at each measurement step. Each measurement mode differs from the others in at least one of the following: maximum target brightness, display frequency, refresh rate, gamma curve, display color, gradation, or adjustment point. The emission waveform output under gamma measurement conditions is not particularly limited.

[0069] Table I below shows an example of gamma measurement conditions.

[0070]

[0071] In this example, the maximum target brightness was changed for each measurement mode. The maximum target brightness for measurement mode 1 was 1900 cd / m². ２ In measurement mode 2, the reading is 850 cd / m². ２ In measurement mode 3, the reading is 270 cd / m². ２ In measurement mode 4, the reading is 54 cd / m². ２ In this example, the maximum target brightness is changed for each measurement mode, but additional measurement modes may be added to change other parameters such as the refresh rate.

[0072] In this embodiment, it is preferable to continuously measure the brightness for multiple measurement modes 1 to 4, which are the same item but differ in their maximum target brightness in this example, then calculate the gamma value from the measured values ​​and perform gamma correction as necessary.

[0073] Generally, when switching the target brightness from high to low, i.e., dimming, electrical charge tends to remain in the electronic circuit. This residual charge in the electronic circuit is called "luminescence residue" or simply "residue." Accurate measurements are impossible if residue remains, so it is necessary to remove the residual charge and refresh the electronic circuit, i.e., eliminate the residue.

[0074] Table II below shows an example of the relationship between the target luminance before and after dimming and the waiting time until the emission residue disappears. The unit of the waiting time in Table II is [sec]. Note that since the detailed value of the residue changes depending on the configuration of the electronic circuit, the waiting time is not necessarily limited to this, but in many devices for measuring general luminance, the relationship shown in Table II is satisfied.

[0075]

[0076] The residue does not always occur during dimming, but occurs when the target luminance before and after dimming satisfies specific conditions. Similarly, the waiting time until the residue disappears also occurs when the target luminance before and after dimming satisfies specific conditions.

[0077] When the target luminance after dimming is not too low, the waiting time until the emission residue disappears does not occur regardless of the target luminance before dimming. Let the minimum value of the target luminance after dimming at this time be B1, and less than B1 be the "low luminance region". When the target luminance after dimming is in the low luminance region (less than B1), depending on the target luminance before dimming, the waiting time until the residue disappears occurs. In an example shown in Table II, B1 is 0.1 cd / m ２ is.

[0078] When the target luminance before dimming is not too high, the waiting time until the emission residue disappears does not occur regardless of the target luminance after dimming. Let the maximum value of the target luminance before dimming at this time be B2, and exceeding B2 be the "high luminance region". When the target luminance before dimming is in the high luminance region (exceeding B2), depending on the target luminance after dimming, the waiting time until the residue disappears occurs. In an example shown in Table II, B2 is 100 cd / m ２ is. Note that the region between the low luminance region and the high luminance region is the "medium luminance region". In an example shown in Table II, less than 0.1 cd / m ２ is the low luminance region, the range of 0.1 to 100 cd / m ２ is the medium luminance region, and exceeding 100 cd / m ２ is the high luminance region.

[0079] In other words, by minimizing the number of times the target brightness decreases from the high-brightness region to the low-brightness region during continuous brightness measurement, the waiting time until the residue is eliminated can be minimized, thereby shortening the measurement time.

[0080] Furthermore, when the target brightness is high, it is preferable to use an ND filter during measurement. If the target brightness is above a predetermined value, the ND filter is inserted into the optical path; if the target brightness is below the predetermined value, the ND filter is removed from the optical path. A waiting time occurs when the ND filter is inserted or removed. Therefore, by minimizing the number of times the target brightness changes to cross the predetermined value before and after dimming, the waiting time for inserting and removing the ND filter can be minimized, and the measurement time can be shortened.

[0081] Table III below shows the waiting time when brightness is measured using the conventional method based on the gamma measurement conditions shown in Table I above. Conventionally, the measurement is performed so that the target brightness gradually increases within the measurement mode. A "-" in the table indicates that no waiting time occurs.

[0082] In this example, the waiting time until the luminescence residue is eliminated is as shown in Table II, and the reference value for inserting and removing the ND filter is 600 cd / m². ２ The waiting time for insertion and removal is set to 300 msec. Note that the reference value for ND filter insertion and removal and the waiting time for insertion and removal operations vary depending on the configuration of the device that measures brightness, so this is not necessarily the case, but most general brightness measuring devices have similar reference values ​​and similar waiting times.

[0083]

[0084] In the example shown in Table III above, measurement step 8 in measurement mode 1 is when the target brightness is within the high brightness range. Also, measurement step 9 in measurement mode 2 is when the target brightness is within the low brightness range. In conventional measurements where the target brightness gradually increases with each measurement mode, a waiting time is likely to occur when switching from measurement mode 1 to 2 because the target brightness decreases from the high brightness range to the low brightness range (from measurement step 8 to 9) until the luminescence residue is eliminated. Also, when switching from measurement mode 1 to 2, the target brightness changes to cross the reference value for inserting and removing the ND filter, so a waiting time is likely to occur for inserting and removing the ND filter. Similarly, waiting times are likely to occur when switching from measurement mode 2 to 3 and from measurement mode 3 to 4.

[0085] On the other hand, in this embodiment, the first measurement mode sets the target brightness from the target brightness in the low brightness region to the target brightness in the high brightness region. The second measurement mode sets the target brightness from the target brightness in the high brightness region, through the target brightness in the medium brightness region, to the target brightness in the low brightness region.

[0086] In this embodiment, the execution order of the measurement steps is set so that the amount of change in target brightness is small when switching measurement modes, and the measurement time can be shortened by minimizing the number of times the light is dimmed from the high-brightness region to the low-brightness region during continuous brightness measurement.

[0087] When there are three or more measurement modes under gamma measurement conditions, the above execution order is set in at least two consecutive measurement modes. Furthermore, from the viewpoint of shortening the measurement time, it is preferable that the above execution order is set even in three or more consecutive measurement modes. Specifically, it is preferable that from the second measurement mode onward, in the third measurement mode the target brightness moves from the low brightness region to the high brightness region, in the fourth measurement mode the target brightness moves from the high brightness region through the medium brightness region to the low brightness region, in the fifth measurement mode the target brightness moves from the low brightness region to the high brightness region, and so on.

[0088] Table IV below shows the waiting time when brightness is measured using the brightness measurement system 100 of this embodiment based on the gamma measurement conditions shown in Table I above. A "-" in the table indicates that no waiting time occurs. In this example, the waiting time until the luminescence residue is eliminated is as shown in Table II, and the reference value for inserting and removing the ND filter is 600 cd / m². ２ The waiting time for insertion and removal operations is set to 300 msec.

[0089]

[0090] In this embodiment, compared to conventional measurements, the number of times the light is dimmed from the high-luminance region to the low-luminance region during continuous luminance measurement is reduced, thus shortening the measurement time. In addition, the number of times the target luminance changes to cross the reference value for inserting and removing the ND filter is reduced, further shortening the measurement time.

[0091] This embodiment will be compared with other embodiments, assuming that the target brightness in both the first and second measurement modes is set to cross the reference value for the insertion and removal of the ND filter.

[0092] In the conventional method described above, the target brightness is set from the low-brightness region to the high-brightness region in the first measurement mode, and also from the low-brightness region to the high-brightness region in the second measurement mode. In this method, first, the ND filter is inserted when the first measurement mode is executed. Next, it is removed when the measurement mode is switched, and then inserted when the second measurement mode is executed. In other words, a total of three insertion and removal operations occur. In other methods, the target brightness is set from the high-brightness region to the low-brightness region in the first measurement mode, and also from the high-brightness region to the low-brightness region in the second measurement mode. In this method, first, an insertion operation occurs before the first measurement mode is executed, and then an removal operation occurs when the first measurement mode is executed. Next, an insertion operation occurs before the second measurement mode is executed, and then an removal operation occurs when the second measurement mode is executed. In other words, a total of four insertion and removal operations occur.

[0093] On the other hand, in this embodiment, first, since the setting starts from the low-luminance region at the start of the first measurement mode, no insertion operation occurs. Next, an insertion operation occurs when the first measurement mode is executed, and an extraction operation occurs when the measurement mode is switched or when the second measurement mode is executed. In other words, a total of two insertion and extraction operations occur. In this embodiment, due to the setting value of the target luminance, the luminance change at the start of mode switching does not cross the reference value for insertion and extraction operations, so the number of insertion and extraction operations that occur can be reduced, and the measurement time can be further shortened. In some cases, the setting starts from the high-luminance region at the start of the first measurement mode, but by setting from the low-luminance region at the start of the second measurement mode and from the high-luminance region at the start of the third measurement mode, the insertion and extraction operations at the start of mode switching can be reduced.

[0094] Figure 5 shows the relationship between measurement time and target brightness in an example shown in Table III. Figure 6 shows the relationship between measurement time and target brightness in an example shown in Table IV. As can be seen from the comparison between Figure 5 and Figure 6, in this embodiment, the measurement time can be shortened by reducing the number of times luminescence residue is generated and by reducing the number of times the ND filter is inserted and removed.

[0095] As mentioned above, it is preferable to sort the execution order of each measurement mode in descending order of highest target brightness. After the execution order of the measurement modes is set, the measurement steps within each measurement mode are sorted and the execution order is set.

[0096] In this embodiment, "from target brightness in the low-brightness region to target brightness in the high-brightness region" means that the measurement of the target brightness in the high-brightness region is performed after the measurement of the target brightness in the low-brightness region is completed. Note that the measurement of the target brightness in the medium-brightness region may be performed before, during, or after the measurement of the target brightness in the low-brightness region, and the measurement of the target brightness in the medium-brightness region may be performed before, during, or after the measurement of the target brightness in the high-brightness region. Furthermore, the order of execution is not restricted for the measurement of target brightness in the low-brightness region or the high-brightness region. By setting the execution order in this way, dimming from the high-brightness region to the low-brightness region is avoided in consecutive brightness measurements, and the number of times luminescence residue is generated can be set to zero.

[0097] In addition, the execution order is preferably such that the number of times the ND filter is inserted and removed is minimized. Preferably, the first measurement step is set to the lowest target brightness within the measurement mode, and preferably the last measurement step is set to the highest target brightness within the measurement mode. This makes it easier to minimize the number of times luminescence residue is generated and the number of times the ND filter is inserted and removed, and allows for more efficient measurement.

[0098] Furthermore, "from the target brightness in the high-brightness region, through the target brightness in the medium-brightness region, to the target brightness in the low-brightness region" means that after the measurement of the target brightness in the high-brightness region is completed, the target brightness in the medium-brightness region is measured at least once, and then the target brightness in the low-brightness region is measured. Note that the target brightness in the medium-brightness region may be measured before or during the measurement of the target brightness in the low-brightness region, and the target brightness in the medium-brightness region may be measured after or during the measurement of the target brightness in the high-brightness region. In addition, there are no restrictions on the order of execution when measuring the target brightness in the low-brightness region or the high-brightness region. By setting the execution order in this way, it is possible to avoid dimming from the high-brightness region to the low-brightness region in consecutive brightness measurements, and to reduce the number of times luminescence residue is generated to zero.

[0099] In addition, the execution order is preferably such that the number of times the ND filter is inserted and removed is minimized. Preferably, the first measurement step is set to the highest target brightness within the measurement mode, and the last measurement step is set to the lowest target brightness within the measurement mode. This makes it easier to minimize the number of times luminescence residue is generated and the number of times the ND filter is inserted and removed, and allows for more efficient measurement.

[0100] Table V below shows the waiting time when brightness is measured using the brightness measurement system 100 of this embodiment based on the gamma measurement conditions shown in Table I above.

[0101] Compared to Table IV, Table V shows that in measurement mode 2, the target luminances for measurement steps 11 and 12 are swapped, and the target luminances for measurement steps 15 and 16 are swapped. Measurement steps 9, 10, and 12 measure the target luminance in the high-luminance region, measurement step 15 measures the target luminance in the low-luminance region, and the other measurement steps measure the target luminance in the medium-luminance region. In other words, even in the example shown in Table V, the measurement of the target luminance in the high-luminance region is completed first, then the target luminance in the medium-luminance region is measured, and then the target luminance in the low-luminance region is measured, thus shortening the measurement time.

[0102]

[0103] In this embodiment, the luminance measurement system 100 includes an image generation unit (second control unit 31), a measurement unit 16, and a control unit (second control unit 31). The image generation unit generates an image signal corresponding to an image to be displayed on the display 40. The measurement unit 16 measures the luminance of the image displayed on the display 40 based on the image signal. The control unit controls the image generation unit and the measurement unit 16 based on a plurality of measurement modes that sequentially perform luminance measurements at a plurality of different target luminances. The control unit executes the first measurement mode and the second measurement mode in sequence. In this case, the first measurement mode sets the target luminance from the target luminance of the low luminance region to the target luminance of the high luminance region and performs luminance measurement. The second measurement mode sets the target luminance from the target luminance of the high luminance region, through the target luminance of the medium luminance region, and down to the target luminance of the low luminance region and performs luminance measurement.

[0104] In this embodiment, the control unit executes the first measurement mode, the second measurement mode, and the third measurement mode in sequence. In this process, the third measurement mode sets the target brightness from the target brightness in the low brightness region to the target brightness in the high brightness region and performs brightness measurement. Preferably, the target brightness for the last brightness measurement in the second measurement mode is set to the lowest target brightness in the second measurement mode, and the target brightness for the first brightness measurement in the third measurement mode is set to the lowest target brightness in the third measurement mode. This makes it easier to minimize the number of times luminescence residue is generated and the number of times the ND filter is inserted and removed, and further improves measurement efficiency.

[0105] In this embodiment, specifically, the low-luminance region is 0.1 cd / m². ２ It is preferable that the range be less than [a certain value].

[0106] In this embodiment, it is preferable that the target luminance for the last luminance measurement in the first measurement mode is set to the highest target luminance in the first measurement mode, and the target luminance for the first luminance measurement in the second measurement mode is set to the highest target luminance in the second measurement mode. This makes it easier to minimize the number of times luminescence residue is generated and the number of times the ND filter is inserted and removed, and further improves measurement efficiency.

[0107] In this embodiment, specifically, the high-brightness region is 100 cd / m². ２ It is preferable that it be in the realm of the super-high.

[0108] In this embodiment, it is preferable that the multiple measurement modes differ from each other in at least one of the following: maximum target brightness, display frequency, refresh rate, gamma curve, display color, gradation, or adjustment point. This allows a single gamma curve under specific conditions to be obtained from a single measurement mode.

[0109] In this embodiment, it is preferable that the multiple measurement modes be set in descending order of highest target brightness. This allows for more efficient measurement.

[0110] In this embodiment, the measuring unit 16 has a light attenuation unit (light attenuation filter 4) that reduces the amount of incident light, and an insertion / removal mechanism (insertion / removal device 5) that inserts and removes the light attenuation unit from the optical path according to the target brightness, and it is preferable that the insertion / removal state of the light attenuation unit is set according to the target brightness. This expands the dynamic range of the brightness measuring device 10.

[0111] In this embodiment, the luminance measuring device 10 comprises an image generation unit (second control unit 31), a measurement unit 16, and a control unit (second control unit 31). The image generation unit generates an image signal corresponding to the image to be displayed on the display 40. The measurement unit 16 measures the luminance of the image displayed on the display 40 based on the image signal. The control unit controls the image generation unit and the measurement unit 16 based on a plurality of measurement modes that sequentially perform luminance measurements at a plurality of different target luminances. The control unit executes the first measurement mode and the second measurement mode in sequence. In this process, the first measurement mode sets the target luminance from the target luminance of the low luminance region to the target luminance of the high luminance region and performs luminance measurement. The second measurement mode sets the target luminance from the target luminance of the high luminance region, through the target luminance of the medium luminance region, and down to the target luminance of the low luminance region and performs luminance measurement.

[0112] In this embodiment, the gamma adjustment system includes a luminance measurement system 100 and a gamma correction unit (second control unit 31) that changes the input / output conversion characteristics of the display 40 based on a gamma value calculated from the measured luminance. This reduces the gamma adjustment time.

[0113] The luminance measurement system 100 performs the luminance measurement method of this embodiment. The luminance measurement method of this embodiment includes an image generation step S23 that generates an image signal corresponding to an image to be displayed on the display, and a measurement step that measures the luminance of an image displayed on the display 40 based on the image signal. The measurement step performs multiple measurement modes that sequentially perform luminance measurements at multiple different target luminances, and the first measurement mode and the second measurement mode are performed in succession. In this case, the first measurement mode sets the target luminance from the target luminance of the low luminance region to the target luminance of the high luminance region and performs luminance measurement. The second measurement mode sets the target luminance from the target luminance of the high luminance region, through the target luminance of the medium luminance region, to the target luminance of the low luminance region and performs luminance measurement.

[0114] In this embodiment, the gamma adjustment method includes a gamma measurement step S12 and a gamma correction step S14. The gamma measurement step S12 measures the brightness using a brightness measurement method and calculates a gamma value from the measured brightness. The gamma correction step S14 changes the input / output conversion characteristics of the display based on the measured gamma value. This shortens the gamma adjustment time.

[0115] In this embodiment, the program causes the computer of the luminance measurement system 100 to execute the first measurement mode and the second measurement mode sequentially. In doing so, the program causes the computer of the luminance measurement system 100 to set the target luminance from the target luminance of the low luminance region to the target luminance of the high luminance region and perform luminance measurement in the first measurement mode. In the second measurement mode, the program causes the computer to set the target luminance from the target luminance of the high luminance region, through the target luminance of the medium luminance region, and down to the target luminance of the low luminance region and perform luminance measurement.

[0116] Furthermore, the detailed configuration and operation of each device constituting the luminance measuring device may also be modified as appropriate, without departing from the spirit of this disclosure.

[0117] This disclosure makes it possible to shorten the time required for measuring brightness. Furthermore, it also shortens the time required for gamma adjustment, which is performed based on brightness measurements.

[0118] 1 Display 2 Light under test 4 Light attenuation filter 5 Insertion / removal device 10 Brightness measuring device 11 Objective optical system 11a Convex lens 11b Aperture diaphragm 12 Branching optical system 13 Colorimetric optical system 131 Color filter 132 Light receiving sensor 14 Electrical processing unit 15 First control unit 16 Measurement unit 17 First display unit 18 First operation unit 19 First communication unit 20 Diffuser plate 30 Management device 31 Second control unit 32 Second display unit 33 Second operation unit 34 Second communication unit 40 Display 41 Third control unit 42 Light emitting unit 43 Third communication unit

Claims

1. A luminance measurement system comprising: an image generation unit that generates an image signal corresponding to an image to be displayed on a display; a measurement unit that measures the brightness of an image displayed on the display based on the image signal; and a control unit that controls the image generation unit and the measurement unit based on a plurality of measurement modes that sequentially perform brightness measurements at a plurality of different target brightness levels, wherein the control unit, when sequentially executing a first measurement mode and a second measurement mode, performs the brightness measurement in the first measurement mode by setting the target brightness from the target brightness of a low brightness region to the target brightness of a high brightness region which is brighter than the low brightness region; and performs the brightness measurement in the second measurement mode by setting the target brightness from the target brightness of the high brightness region, through the target brightness of a medium brightness region between the low brightness region and the high brightness region, to the target brightness of the low brightness region.

2. The luminance measurement system according to claim 1, wherein when the control unit executes the first measurement mode, the second measurement mode, and the third measurement mode in sequence, the third measurement mode sets the target luminance from the target luminance of the low luminance region to the target luminance of the high luminance region and performs the luminance measurement, the target luminance for the last luminance measurement in the second measurement mode is set to the lowest target luminance in the second measurement mode, and the target luminance for the first luminance measurement in the third measurement mode is set to the lowest target luminance in the third measurement mode.

3. The low-luminance region is 0.1 cd / m². ２ The luminance measurement system according to claim 1, wherein the region is less than the specified range.

4. The luminance measurement system according to claim 1, wherein the target luminance for the last luminance measurement in the first measurement mode is set to the highest target luminance in the first measurement mode, and the target luminance for the first luminance measurement in the second measurement mode is set to the highest target luminance in the second measurement mode.

5. The high-brightness region is 100 cd / m². ２ The luminance measurement system according to claim 1, which is in the realm of ultra-high performance.

6. The luminance measurement system according to claim 1, wherein the plurality of measurement modes differ from each other in at least one of the following: maximum target luminance, display frequency, refresh rate, gamma curve, display color, gradation, or adjustment point.

7. The luminance measurement system according to claim 1, wherein the plurality of measurement modes are set in descending order of highest target luminance.

8. The luminance measurement system according to any one of claims 1 to 7, wherein the measuring unit comprises a light attenuation unit that reduces the amount of incident light, and an insertion / removal mechanism that inserts and removes the light attenuation unit from the optical path according to the target luminance, and the insertion / removal state of the light attenuation unit is set according to the target luminance.

9. A luminance measuring device comprising: an image generation unit that generates an image signal corresponding to an image displayed on a display; a measurement unit that measures the brightness of an image displayed on the display based on the image signal; and a control unit that controls the image generation unit and the measurement unit based on a plurality of measurement modes that sequentially perform brightness measurements at a plurality of different target brightness levels, wherein the control unit, when sequentially performing a first measurement mode and a second measurement mode, performs the brightness measurement by setting the target brightness from the target brightness of a low brightness region to the target brightness of a high brightness region which is brighter than the low brightness region in the first measurement mode; and sets the target brightness from the target brightness of the high brightness region, through the target brightness of a medium brightness region between the low brightness region and the high brightness region, to the target brightness of the low brightness region in the second measurement mode.

10. A gamma adjustment system comprising: a luminance measurement system according to any one of claims 1 to 7; and a gamma correction unit that changes the input / output conversion characteristics of the display based on a gamma value calculated from the measured luminance.

11. A gamma adjustment system comprising: a luminance measurement system according to claim 8; and a gamma correction unit that changes the input / output conversion characteristics of the display based on a gamma value calculated from the measured luminance.

12. A luminance measurement method performed by a luminance measurement system, comprising: an image generation step of generating an image signal corresponding to an image to be displayed on a display; and a measurement step of measuring the luminance of an image displayed on the display based on the image signal, wherein the measurement step performs a plurality of measurement modes that sequentially perform luminance measurements at a plurality of different target luminances, and when the first measurement mode and the second measurement mode are performed in succession, the first measurement mode sets the target luminance from the target luminance of a low-luminance region to the target luminance of a high-luminance region which is brighter than the low-luminance region and performs the luminance measurement; and the second measurement mode sets the target luminance from the target luminance of the high-luminance region, through the target luminance of a medium-luminance region between the low-luminance region and the high-luminance region, to the target luminance of the low-luminance region and performs the luminance measurement.

13. The luminance measurement method according to claim 12, wherein the measurement step is performed in sequence, the first measurement mode, the second measurement mode and the third measurement mode, the third measurement mode sets the target luminance from the target luminance of the low luminance region to the target luminance of the high luminance region and performs the luminance measurement, the target luminance for the last luminance measurement in the second measurement mode is set to the lowest target luminance in the second measurement mode, and the target luminance for the first luminance measurement in the third measurement mode is set to the lowest target luminance in the third measurement mode.

14. The low-luminance region is 0.1 cd / m². ２ The luminance measurement method according to claim 12, wherein the region is less than the specified range.

15. The luminance measurement method according to claim 12, wherein the target luminance for the last luminance measurement in the first measurement mode is set to the highest target luminance in the first measurement mode, and the target luminance for the first luminance measurement in the second measurement mode is set to the highest target luminance in the second measurement mode.

16. The high-brightness region is 100 cd / m². ２ The luminance measurement method according to claim 12, which is in the realm of ultra-high performance.

17. The luminance measurement method according to claim 12, wherein the plurality of measurement modes differ from each other in at least one of the maximum target luminance, display frequency, refresh rate, gamma curve, display color, gradation, or adjustment point.

18. The luminance measurement method according to claim 12, wherein the plurality of measurement modes are set in descending order of highest target luminance.

19. The luminance measurement method according to any one of claims 12 to 18, wherein the measurement step includes an insertion / removal step of inserting and removing a light attenuator that reduces the amount of incident light in accordance with the target luminance, and the insertion / removal state of the light attenuator is set according to the target luminance.

20. A gamma adjustment method comprising: a gamma measurement step of measuring luminance using the luminance measurement method described in any one of claims 12 to 18 and calculating a gamma value from the measured luminance; and a gamma correction step of changing the input / output conversion characteristics of the display based on the measured gamma value.

21. A gamma adjustment method comprising: a gamma measurement step of measuring luminance using the luminance measurement method described in claim 19 and calculating a gamma value from the measured luminance; and a gamma correction step of changing the input / output conversion characteristics of the display based on the measured gamma value.

22. A program for a luminance measurement system computer comprising: an image generation unit that generates an image signal corresponding to an image to be displayed on a display; a measurement unit that measures the brightness of an image displayed on the display based on the image signal; and a control unit that controls the image generation unit and the measurement unit based on a plurality of measurement modes that sequentially perform brightness measurements at a plurality of different target brightness levels, wherein the computer is made to execute a first measurement mode and a second measurement mode in sequence, wherein the first measurement mode is a program that sets the target brightness from the target brightness of a low brightness region to the target brightness of a high brightness region which is brighter than the low brightness region and performs the brightness measurement, and the second measurement mode is a program that sets the target brightness from the target brightness of the high brightness region, through the target brightness of a medium brightness region between the low brightness region and the high brightness region, to the target brightness of the low brightness region and performs the brightness measurement.

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