Display light measuring apparatus, light measuring method, and program

Abstract

To provide a display light measuring apparatus, a measuring method, and a program capable of suppressing errors caused by residual charges of an integration capacitor in an integration circuit.SOLUTION: A display light measuring apparatus includes: optical sensors 41 to 43; integration circuits 51 to 53 each having an integration capacitor, the integration circuits being configured to accumulate charges output from the optical sensors; light quantity limiting means 90 for limiting a quantity of incident light to the optical sensors; trigger detection means 93 for detecting a trigger signal serving as a trigger for operating the light quantity limiting means 90 to limit the light quantity; reception means 7 for receiving a command to perform a measurement operation; and control means 7 for operating the light quantity limiting means 90 to limit the light quantity on the basis of the detection of the trigger signal and releasing the light quantity limitation by the light quantity limiting means 90 on the basis of the received command for the measurement operation.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a display light measurement device, a light measurement method, and a program for measuring the luminance, color, etc. of a display. [Background technology]

[0002] A known example of such an optical measurement device is a display color analyzer (one example is the CA-410 manufactured by Konica Minolta, Inc.). Such a display color analyzer has an internal optical sensor equivalent to a spectral responsivity and acquires stimulus values.

[0003] There are two main methods for acquiring stimulus values: the sequential acquisition method, which acquires instantaneous values, and the integral acquisition method, which acquires integrated values ​​over a set period of time. The sequential acquisition method excels at high speed, but integrating circuits are preferred and widely used as a means of measuring a wide range of luminance from low to high while achieving a high S / N ratio. In particular, in recent years, advances in technology to reduce dark current and circuit noise have made it possible for integrating circuits to integrate for long periods of time. As they will be able to handle weaker photocurrents, further improvements in low-luminance performance are expected.

[0004] Patent Document 1 discloses a photodetector that includes the above-mentioned integrating circuit and has a wide dynamic range and an improved S / N ratio.

[0005] Furthermore, Patent Document 2 discloses a photodetector capable of measuring luminance over a wide range and with a high S / N ratio without increasing costs.

[0006] Meanwhile, zero calibration is a method for suppressing measurement errors caused by the dark current of the optical sensor and the offset of the circuit.

[0007] Zero calibration is a process in which an output value (zero calibration value) is prepared when the index value should be set to zero, and the zero calibration value is subtracted from the output value (obtained when the optical path is open) during optical measurement.

[0008] The zero calibration value is generated from the dark output value, which is the output value acquired when the optical path to the optical sensor is closed and light is blocked. The dark output value is acquired under conditions that allow the generation of a zero calibration value that corresponds to the photometric conditions used during light measurement (for example, integration time and capacity of the integration circuit (circuit gain)).

[0009] For example, in the case of a system with multiple circuit gains, a zero calibration value corresponding to each circuit gain is required, so the dark output value to be acquired will naturally be acquired under multiple conditions. Basically, the dark output is acquired for each circuit gain, but if it can be made common across multiple circuit gains, the number of acquisition conditions can be reduced.

[0010] As with circuit gain, the integration time must be acquired under conditions that allow for the generation of a zero calibration value that corresponds to the photometric conditions during light measurement. The same photometric conditions are not necessarily required, as long as an approximately equal value is acquired so that errors can be ignored.

[0011] There are two main types of timing for acquiring the dark output value for zero calibration. The first is a method in which the dark output value is acquired for each optical measurement (immediate type). The second is a method in which the dark output value is acquired and stored in advance before measurement is performed (advance type).

[0012] Immediate zero calibration is performed consecutively with the optical measurement, either immediately before or immediately after the optical measurement. When performed immediately after the optical measurement, the photometric conditions used in the optical measurement are known, so there is an advantage that the dark output value only needs to be obtained under one condition (the same conditions as the optical measurement performed immediately before).

[0013] Pre-calibration of the zero point calibration type is generally performed at the following times (1) to (3): (1) at startup, (2) when the temperature sensor output value exceeds the allowable range based on the previous zero calibration (this is done to reduce drift errors), (3) when requested by the user, etc. Since the photometric conditions during light measurement are unknown, it is common to obtain all dark output values ​​in advance for multiple major conditions.

[0014] Furthermore, in order to expand the measurement brightness range, a mechanism for limiting the amount of light incident on the optical sensor by, for example, a dimming means may be provided. [Prior art documents] [Patent documents]

[0015] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-321313 [Patent Document 2] International Publication No. 2018-198674 Summary of the Invention [Problem to be solved by the invention]

[0016] In an optical measurement device equipped with an integrating circuit, a reset operation is required to transition an integrating capacitor in the integrating circuit to a reference potential before measurement is performed.

[0017] When an optical measurement device equipped with an integrating circuit is used and the integrating circuit is operated under the conditions A and B below, the integrating operation will begin before the integrating capacitor reaches the reference potential (a charge signal remains). A: When zero calibration is performed while the display, which is the object to be measured, is turned on (during zero calibration) B: When the measurement is performed immediately after dimming the display brightness (at the time of measurement) Measurements using output values ​​acquired under conditions A and B above may result in errors due to slight residual charges.

[0018] For example, in the above "A: During zero calibration," the acquired dark output value has a slight error due to residual charge, so if measurement in the low luminance range is performed using the above zero calibration value, a slight error will occur. Also, in the above "B: During measurement," measurement in the low luminance range will include a slight error in the light output value due to residual charge.

[0019] Conventionally, in display measurement, there is a limit to the low brightness performance that can be expressed, so errors due to this slight residual charge do not pose a problem.

[0020] However, in recent years, the dynamic range of brightness that displays can express has expanded both in high and low brightness, which has led to the problem that errors due to slight residual charges during the above-mentioned zero calibration and measurement cannot be ignored.

[0021] An object of the present invention is to provide a display light measurement device, a measurement method, and a program that can suppress errors due to residual charge in an integrating capacitor of an integrating circuit. [Means for solving the problem]

[0022] The above object can be achieved by the following means: (1) an optical sensor; an integration circuit having an integration capacitor for accumulating the charge output from the photosensor; a light amount limiting means for limiting the amount of light entering the optical sensor; a trigger detection means for detecting a trigger signal that triggers the light amount limiting means to limit the amount of light; a receiving means for receiving a command to perform a measurement operation; a control means for operating the light amount limiting means to limit the amount of light based on the detection of a trigger signal by the trigger detecting means, and for releasing the light amount limiting by the light amount limiting means based on a measurement operation command received by the receiving means; A display light measurement device comprising: (2) The display light measurement device according to the preceding paragraph 1, wherein the trigger signal is a signal generated as a trigger when a user performs an operation on the display light measurement device to activate the display light measurement device. (3) an optical sensor; an integration circuit having an integration capacitor for accumulating the charge output from the photosensor; a light amount limiting means for limiting the amount of light entering the optical sensor; a receiving means for receiving a command to perform a measurement operation; a control means for releasing the restriction imposed by the light amount restriction means based on the measurement operation command received by the receiving means, and for operating the light amount restriction means to restrict the light amount at the end of the measurement operation; A display light measurement device comprising: (4) an optical sensor; an integration circuit having an integration capacitor for accumulating the charge output from the photosensor; a light amount limiting means for limiting the amount of light entering the optical sensor; a trigger detection means for detecting a trigger signal that triggers the stop of operation of the display light measurement device; a receiving means for receiving a command to perform a measurement operation; a control means for releasing the restriction imposed by the light amount restriction means based on the measurement operation command received by the receiving means, and for operating the light amount restriction means to restrict the light amount based on detection of a trigger signal by the trigger detection means; A display light measurement device comprising: (5) The display light measurement device according to the preceding paragraph 4, wherein the trigger signal is a signal generated as a trigger when a user performs an operation on the display light measurement device to stop the operation of the display light measurement device. (6) an optical sensor; an integration circuit having an integration capacitor for accumulating the charge output from the photosensor; a light amount limiting means for limiting the amount of light entering the optical sensor; a calibration means for performing zero calibration; a receiving means for receiving a command to perform a measurement operation; a control means for operating the light amount limiting means to limit the amount of light when a measurement operation performed based on the measurement operation command received by the receiving means is completed and when zero calibration is completed; A display light measurement device comprising: (7) an optical sensor; an integration circuit having an integration capacitor for accumulating the charge output from the photosensor; a light amount limiting means for limiting the amount of light entering the optical sensor; a calibration means for performing zero calibration; a receiving means for receiving a command to perform a measurement operation; a control means for acquiring a zero calibration value based on the measurement operation command received by the receiving means, and releasing the restriction imposed by the light amount restriction means upon completion of acquisition of the zero calibration value, and starting the measurement operation; A display light measurement device comprising: (8) A display light measurement device as described in paragraph 1 or 4 above, wherein the control means releases the light quantity limitation by the light quantity limiting means based on the reception of the command by the reception means, and activates the light quantity limiting means to limit the light quantity at the end of the measurement operation. (9) A display light measurement device according to any one of the preceding paragraphs 1 to 7, wherein the light quantity limiting means is plural, and the control unit does not limit the light quantity limiting operation and the limit release operation to a specific light quantity limiting means. (10) The display light measurement device according to any one of the above paragraphs 1 to 7, wherein a user can select whether or not to limit the amount of light by the light amount limiting means. (11) an optical sensor; an integration circuit having an integration capacitor for accumulating the charge output from the photosensor; a light amount limiting means for limiting the amount of light entering the optical sensor; A display light measurement device comprising: detecting a trigger signal that triggers the light amount limiting means to operate so as to limit the amount of light; Accepts a command to perform measurement operation, activating the light amount limiting means to limit the amount of light based on the detection of the trigger signal, and canceling the light amount limiting by the light amount limiting means based on the command; A display light measurement method comprising: (12) an optical sensor; an integration circuit having an integration capacitor for accumulating the charge output from the photosensor; a light amount limiting means for limiting the amount of light entering the optical sensor; A display light measurement device comprising: Accepts a command to perform measurement operation, releases the restriction imposed by the light amount restriction means based on the command, and activates the light amount restriction means to restrict the light amount at the end of the measurement operation; A display light measurement method comprising: (13) an optical sensor; an integration circuit having an integration capacitor for accumulating the charge output from the photosensor; a light amount limiting means for limiting the amount of light entering the optical sensor; A display light measurement device comprising: Detecting a trigger signal that triggers the stop of operation of the display light measurement device; Accepts a command to perform measurement operation, releasing the restriction imposed by the light amount restriction means based on the command, and activating the light amount restriction means to restrict the light amount based on detection of a trigger signal by the trigger detection means; A display light measurement method comprising: (14) an optical sensor; an integration circuit having an integration capacitor for accumulating the charge output from the photosensor; a light amount limiting means for limiting the amount of light entering the optical sensor; A display light measurement device comprising: Perform zero calibration, Accepts a command to perform measurement operation, activating the light amount limiting means to limit the amount of light at the end of the measurement operation performed based on the command and at the end of zero calibration; A display light measurement method comprising: (15) an optical sensor; an integration circuit having an integration capacitor for accumulating the charge output from the photosensor; a light amount limiting means for limiting the amount of light entering the optical sensor; A display light measurement device comprising: Perform zero calibration, Accepts a command to perform measurement operation, a zero calibration value is acquired based on the command, and when acquisition of the zero calibration value is completed, the restriction by the light amount restriction means is released and a measurement operation is started. A display light measurement method comprising: (16) an optical sensor; an integration circuit having an integration capacitor for accumulating the charge output from the photosensor; a light amount limiting means for limiting the amount of light entering the optical sensor; A computer of a display light measurement device equipped with detecting a trigger signal that triggers the light amount limiting means to operate so as to limit the amount of light; Accepts a command to perform measurement operation, activating the light amount limiting means to limit the amount of light based on the detection of the trigger signal, and canceling the light amount limiting by the light amount limiting means based on the command; A program for executing a process. (17) an optical sensor; an integration circuit having an integration capacitor for accumulating the charge output from the photosensor; a light amount limiting means for limiting the amount of light entering the optical sensor; A computer of a display light measurement device equipped with Accepts a command to perform measurement operation, releases the restriction imposed by the light amount restriction means based on the command, and activates the light amount restriction means to restrict the light amount at the end of the measurement operation; A program for executing a process. (18) an optical sensor; an integration circuit having an integration capacitor for accumulating the charge output from the photosensor; a light amount limiting means for limiting the amount of light entering the optical sensor; A computer of a display light measurement device equipped with Detecting a trigger signal that triggers the stop of operation of the display light measurement device; Accepts a command to perform measurement operation, releasing the restriction imposed by the light amount restriction means based on the command, and activating the light amount restriction means to restrict the light amount based on detection of a trigger signal by the trigger detection means; A program for executing a process. (19) an optical sensor; an integration circuit having an integration capacitor for accumulating the charge output from the photosensor; a light amount limiting means for limiting the amount of light entering the optical sensor; A computer of a display light measurement device equipped with Perform zero calibration, Accepts a command to perform measurement operation, activating the light amount limiting means to limit the amount of light at the end of the measurement operation performed based on the command and at the end of zero calibration; A program for executing a process. (20) an optical sensor; an integration circuit having an integration capacitor for accumulating the charge output from the photosensor; a light amount limiting means for limiting the amount of light entering the optical sensor; A computer of a display light measurement device equipped with Perform zero calibration, Accepts a command to perform measurement operation, a zero calibration value is acquired based on the command, and when acquisition of the zero calibration value is completed, the restriction by the light amount restriction means is released and a measurement operation is started. A program for executing a process. [Effects of the Invention]

[0023] According to the inventions set forth in paragraphs (1), (11), and (16), the light quantity limiting means is activated based on the detection of a trigger signal that triggers activation of the light quantity limiting means to limit the quantity of light reaching the optical sensor, thereby limiting the quantity of light reaching the optical sensor. Furthermore, the light quantity limiting means is released based on a command to perform a measurement operation. Therefore, the light quantity limiting means operates to limit the quantity of light reaching the optical sensor until a measurement is performed based on a command to perform a measurement operation, thereby reducing the residual charge in the integrating capacitor and enabling highly accurate measurements.

[0024] According to the invention relating to the preceding paragraph (2), the operation performed by the user on the display light measurement device to activate the display light measurement device is used as a trigger to activate the light amount limiting means, thereby limiting the amount of light to the light sensor.

[0025] According to the inventions described in the preceding paragraphs (3), (12), and (17), the limitation by the light quantity limiting means is released based on a command to perform a measurement operation. Furthermore, the light quantity limiting means operates to limit the amount of light reaching the optical sensor when the measurement operation is completed. Therefore, after the end of a measurement, the light quantity limiting means operates to limit the amount of light reaching the optical sensor until the next measurement, thereby reducing the residual charge in the integrating capacitor and enabling highly accurate measurements.

[0026] According to the inventions of the preceding paragraphs (4), (13), and (18), the limitation by the light amount limiting means is released based on a command to perform a measurement operation. Furthermore, the light amount limiting means is activated based on the detection of a trigger signal that triggers the stop of operation of the display light measuring device, limiting the amount of light reaching the optical sensor. Therefore, after the detection of the trigger signal that triggers the stop of operation of the display light measuring device, the light amount limiting means operates to limit the amount of light reaching the optical sensor until the next measurement, thereby reducing the residual charge in the integrating capacitor and enabling highly accurate measurements.

[0027] According to the invention relating to the preceding paragraph (5), the operation performed by the user on the display light measurement device to stop the operation of the display light measurement device is used as a trigger to activate the light amount limiting means and limit the amount of light to the light sensor.

[0028] According to the inventions of the preceding paragraphs (6), (14), and (19), the light amount limiting means operates to limit the amount of light after the measurement operation performed based on the command to perform the measurement operation has ended and at the end of zero calibration. Therefore, the light amount limiting means operates to limit the amount of light to the optical sensor until zero calibration is performed and until measurement is performed, so that the residual charge in the integrating capacitor can be reduced, enabling highly accurate measurement and zero calibration.

[0029] According to the inventions of the preceding paragraphs (7), (15), and (20), a zero calibration value is acquired based on a command to perform a measurement operation. After the zero calibration value is acquired, the restriction by the light amount limiting means is released, and the measurement operation is started. Therefore, the residual charge in the integrating capacitor can be reduced in the instantaneous zero calibration, enabling highly accurate zero calibration and measurement.

[0030] According to the invention related to the preceding paragraph (8), the light quantity limiting means is activated at the end of the measurement operation to limit the quantity of light reaching the optical sensor, so that the residual charge in the integrating capacitor can be reduced before the next measurement, enabling highly accurate measurements.

[0031] According to the invention related to the preceding paragraph (9), there are a plurality of light quantity limiting means, and the light quantity limiting operation and the limit release operation are not limited to a specific light quantity limiting means. Therefore, the number of times the light quantity limiting means is executed is distributed among the plurality of light quantity limiting means, which improves the durability of the mechanically moving parts of the light quantity limiting means and ultimately allows the residual charge suppression function to be maintained for a long period of time.

[0032] According to the invention relating to the preceding paragraph (10), the user can select whether or not to limit the amount of light by the light amount limiting means. [Brief explanation of the drawings]

[0033] [Figure 1] 1 is a block diagram showing the configuration of a display light measurement device 1 according to an embodiment of the present invention. [Figure 2]FIG. 2 is a state transition diagram of the display light measurement device according to the first embodiment. [Figure 3] 1 is a flowchart showing the operation at the time of startup of the display light measurement device according to the first embodiment. [Figure 4] 10 is a flowchart showing the operation of the display light measurement device according to the first embodiment at the time of zero calibration. [Figure 5] 10 is a flowchart showing the operation in a standby state of the display light measurement device according to the first embodiment. [Figure 6] 1 is a flowchart showing the operation of the display light measurement device according to the first embodiment when performing measurement. [Figure 7] 7A and 7B are examples of timing charts of the operation of the display light measurement device according to the first embodiment. [Figure 8] FIG. 10 is a state transition diagram of the display light measurement device in the second embodiment. [Figure 9] 10 is a flowchart showing the operation at the time of startup of the display light measurement device according to the second embodiment. [Figure 10] 10 is a flowchart showing the operation of the display light measurement device according to the second embodiment at the time of zero calibration. [Figure 11] 10 is a flowchart showing the operation of the display light measurement device according to the second embodiment when performing measurement. [Figure 12] 10 is a flowchart showing the operation of the display light measurement device according to the second embodiment when the device is stopped. DETAILED DESCRIPTION OF THE INVENTION

[0034] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0035] FIG. 1 is a block diagram showing the configuration of a display light measurement device 1 according to an embodiment of the present invention.

[0036] The display light measurement device 1 includes a focusing unit 2, a light quantity limiting means 90, an optical path branching unit 3, three optical sensors 41-43, three current integration circuits 51-53, three A / D converters 61-63, a control unit 7, a memory unit 8, a trigger detection means 93, and a measurement operation command means 94.

[0037] The light collecting unit 2 is made up of a collecting lens and the like, and collects light emitted from a display, which is the object to be measured.

[0038] In this embodiment, the light amount limiting means 90 is made up of a light blocking means 91 and a light reducing means 92 .

[0039] The light blocking means 91 is a member that blocks incident light to the optical sensors 41 to 43 during zero calibration, and is provided so as to be able to open and close the incident light path to the optical sensors 41 to 43. The light blocking means 91 may be, for example, a shutter.

[0040] The light-reducing means 92 is a member that limits the amount of light incident on the optical sensors 41 to 43 in order to expand the measurement brightness range, and is provided so as to be insertable into and removable from the incident light path to the optical sensors 41 to 43. As the light-reducing means 92, for example, an ND filter is used.

[0041] The light amount limiting means 90 is a member that limits the amount of light incident on the optical sensors 41 to 43 to a level where errors due to residual charges do not become a problem. In this embodiment, the light amount limiting means 90 is of two types: a light blocking means 91 and a light attenuating means 92, which are operated by separate drive mechanisms, but three or more types that are movable by separate drive mechanisms may be provided. Alternatively, only the light blocking means 91 may be provided. Other examples of the light amount limiting means 90 include an adjustable aperture, a slit, and a filter member that is arranged to be freely advanced and retreated relative to the optical path.

[0042] The optical path branching unit 3 branches the optical path of the light condensed by the light condensing unit 2 into three.

[0043] The optical sensors 41 to 43 receive light along each of the three optical paths branched by the optical path branching unit 3. The optical sensors 41 to 43 may be of a tristimulus value direct reading type or a spectroscopic type.

[0044] The current integration circuits 51 to 53 accumulate the electric charges output from the optical sensors 41 to 43 in their respective integration capacitors, and output an output value according to the amount of accumulated electric charge. In this embodiment, each of the current integration circuits 51 to 53 has a plurality of selectable gains. In other words, the capacitance of the integration capacitor can be changed to a plurality of values.

[0045] A / D converters 61 to 63 convert the output values ​​of the current integration circuits 51 to 53 into digital signals.

[0046] The optical sensors 41 to 43, the current integration circuits 51 to 53, and parts of the A / D converters 61 to 63 form an analog circuit section.

[0047] The control unit 7 comprehensively controls the entire display light measurement device 1. For example, it activates / deactivates the light amount limiting means 91, 92, drives the current integration circuits 51-53, calculates stimulus values ​​based on the output signal values ​​of the A / D converters 61-63, and communicates with an external device (not shown) such as a personal computer. The calculated stimulus values ​​include, for example, luminance, chromaticity (xy), and tristimulus values ​​represented by XYZ. The control unit 7 also performs zero calibration. The zero calibration is performed by the control unit 7 acquiring dark output values, which are output values ​​of the amount of light incident on the optical sensors 41-43, while the light blocking means 91 blocks light incident on the optical sensors 41-43. The control unit 7 then calibrates the measurement values ​​based on the acquired dark output values.

[0048] The control unit 7 is configured by a computer equipped with a hardware processor such as a CPU, a ROM, and the like.

[0049] The storage unit 8 stores a control program for the display light measurement device 1, calibration values ​​for converting the output values ​​of the optical sensors 41 to 43 into measurement index values, and the like.

[0050] The trigger detection means 93 detects a trigger signal. The trigger detection means 93 may be configured as part of the functions of the control unit 7. One of the trigger signals is a signal that triggers the light amount limiting means 90 to operate so as to limit the amount of light to the optical sensors 41 to 43. In other words, this signal is a signal that causes the display light measurement device 1 to transition to startup processing. This signal may be a signal that is generated as a trigger when a user operates the display light measurement device 1 to operate it.

[0051] Another trigger signal is a signal that triggers the stop of operation of the display light measurement device 1. This signal may be a signal that is generated as a trigger when a user performs an operation on the display light measurement device 1 to stop the operation of the display light measurement device 1.

[0052] Specific examples of trigger signals include a detection signal from a current detector (e.g., USB bus power detection), an on / off signal from a power switch provided in the display light measurement device 1, a detection signal from an acceleration sensor, a detection signal from a posture sensor, etc.

[0053] The measurement operation command receiving means 94 receives an optical measurement execution command. Specifically, it receives a measurement start button operation by the user. Alternatively, it receives a measurement operation command from an IC board or the like that has received a measurement execution command from an information processing device such as a PC. The measurement operation command receiving means may be configured as part of the functions of the control unit 7. [Embodiment 1] Next, a first embodiment of the display light measurement device 1 will be described with reference to the state transition diagram of the display light measurement device 1 in FIG. 2, the flowcharts in FIGS. 3 to 6, and an example of timing charts in FIGS. 7A and 7B.

[0054] This embodiment 1 is applied to a method (pre-type) in which dark output values ​​for zero calibration are acquired and stored in advance before measurement is performed. As described above, the dark output values ​​are output values ​​acquired in a light-blocking state in which the optical paths of the optical sensors 41 to 43 are closed.

[0055] In the state transition diagram of Figure 2, when the power is turned on, the display light measurement device 1 detects this as a trigger signal and performs startup processing in step S01. When the display light measurement device 1 receives a zero calibration execution command, it performs zero calibration in step S02.

[0056] After the zero calibration is completed, the display light measurement device 1 goes into a standby state in step S03. When a zero calibration execution command is received in the standby state, the display light measurement device 1 returns to step S02 and performs the zero calibration.

[0057] When a measurement operation command is received in the standby state, the display light measurement device 1 performs measurement in step S04. After completing the measurement, the display light measurement device 1 returns to step S03 and enters standby state again, after which it repeats the standby of step S03, zero calibration of step S02 as needed, and measurement of step S04. When the user turns off the power, the display light measurement device 1 detects the power-off as a trigger signal and transitions to the stopped state.

[0058] The flowchart in Fig. 3 shows the operation at startup, the flowchart in Fig. 4 shows the operation at zero calibration, the flowchart in Fig. 5 shows the operation in standby state, and the flowchart in Fig. 6 shows the operation at measurement execution. The operations shown in the flowcharts from Fig. 3 onwards are executed by the processor of the control unit 7 of the display light measurement device 1 operating in accordance with the operation program.

[0059] FIG. 7A shows a timing chart for start-up, standby state, and zero calibration, and FIG. 7B shows a timing chart for measurement execution. (Startup behavior) When the control unit 7 detects the trigger signal generated when the power is turned on via the trigger detection means 93, the control unit 7 performs the startup process in step S11 of Fig. 3. As mentioned above, the trigger signal is not limited to the signal generated when the power is turned on, and may be any signal that triggers the display light measurement device 1 to perform the startup process.

[0060] The startup process in step S11 is the same as that of a conventional display light measurement device, so a description thereof will be omitted. The operation of the display light measurement device 1 after the startup process is completed is the same as the operation in the standby state described below.

[0061] Furthermore, in step S12, the control unit 7 activates the light amount limiting means 90 based on the detection of the trigger signal, thereby limiting the amount of light reaching the optical sensors 41 to 43. The reason for this is to suppress errors due to residual charges that occur during zero calibration.

[0062] The light quantity limiting means 90 to be activated may be at least one of the light blocking means (shutter) 91 and the light attenuation means (ND filter) 92, but it is preferable to activate the light blocking means 91. The reason for this is as follows: the next state after startup is "zero calibration," and the light blocking means 91 must be activated during zero calibration. Therefore, by activating the light blocking means 91 in advance and maintaining the activated state, there is no need to newly activate the light blocking means 91 during zero calibration, and the takt time can be shortened accordingly. Furthermore, compared to activating the light attenuation means 92 after startup and activating the light blocking means 91 during zero calibration, the overall number of times the light quantity limiting means 90 is mechanically driven is reduced, thereby improving durability.

[0063] The timing of the light amount restriction in the startup process is not limited to this. For example, the startup process in step S11 and the operation process of the light amount restriction means 90 in step S12 may be performed simultaneously or vice versa. (Operation during zero calibration) When the control unit 7 receives a command to execute zero calibration, it closes the light blocking means (shutter) 91 to acquire the dark output value in step S21 of Fig. 4. However, if the light blocking means 91 has already been activated in step S12 of Fig. 3, step S21 is omitted. In this embodiment, in order to reduce errors caused by leaking light, the light attenuating means 92 is also forcibly inserted into the optical path. However, the light attenuating means 92 does not have to be inserted into the optical path.

[0064] Next, in step S22, the control unit 7 acquires dark output values ​​under a plurality of predetermined photometric conditions. In this embodiment, as shown by the timing chart in FIG. 7A, the control unit 7 acquires dark output values ​​four times under the condition of an exposure time of 1 / 30 [sec] (one integration time) while switching the gain of the current integration circuits 51-53. Since the light amount limiting means 90 is already activated when the display light measurement device 1 is started and the amount of light incident on the optical sensors 41-43 is limited, the residual charge in the integration capacitors of the current integration circuits 51-53 is sufficiently suppressed when the dark output values ​​are acquired.

[0065] In step S23, the control unit 7 performs arithmetic processing on the dark output value acquired in step S22 as needed to generate a zero calibration value. One example of the arithmetic processing is normalization by integration time. The generated zero calibration value is stored in the memory unit 8 or the like.

[0066] In step S24, the control unit 7 operates the light quantity limiting means 90 in order to suppress errors due to residual charges that occur during measurement, since the next state is measurement. As in this embodiment, when the light path to the optical sensors 41 to 43 has already been blocked by the light blocking means 91, the light blocking state is maintained. This eliminates the need to newly operate the light quantity limiting means 90, shortening the takt time and preventing wear on the drive mechanism of the light quantity limiting means 90.

[0067] On the other hand, the light attenuating means 92 is retracted from the optical path and returned to the state before the start of zero calibration. This makes it possible to perform the next measurement as quickly as before zero calibration. Note that if the light attenuating means 92 is not inserted into the optical path during zero calibration, the light attenuating means 92 remains in the non-inserted state.

[0068] Thereafter, the display light measurement device 1 transitions to a standby state in step S03 of FIG. (Operation in standby mode) In this embodiment, the current integration circuits 51-53 are operated even during standby. The operation of the current integration circuits 51-53 resets the integration capacitance, preventing the current integration circuits 51-53 from falling into an oversaturated state (because if they do, it takes time to return to an appropriate state). Furthermore, the light intensity limiting means 90 remains active during standby due to the processing of step S24 in FIG. 4 or step S44 in FIG. 6, which will be described later.

[0069] In step S31 of FIG. 5, the control unit 7 sets the gain of each of the current integration circuits 51-53. During standby, the control unit 7 sets the gain of the current integration circuits 51-53 to minimum (maximum capacitance of the integration capacitor) to avoid saturation of the current integration circuits 51-53 due to exposure to high luminance. If the current integration circuits 51-53 saturate, the reset time will be extended. However, this is not limited to this. Even if the previous settings are continued without changing the gain settings of the current integration circuits 51-53, this is highly unlikely to cause a problem because the light amount limiting means 90 is in operation.

[0070] Next, in step S32, the control unit 7 sets the integration conditions (integration time, integration period, etc.) In this embodiment, both the integration time and integration period are set to 0.3 msec.

[0071] Next, in step S33, the control unit 7 performs photometry (integration) under the conditions determined in step S32. The control unit 7 repeatedly performs the following steps (1) to (3) until it receives a measurement execution command or a zero calibration execution command. (1) The control unit 7 starts integration after resetting each of the current integration circuits 51 to 53. (2) The control unit 7 samples and holds the output values ​​of the current integration circuits 51 to 53 after a predetermined time (0.3 msec) has elapsed. (3) After completing (2), the process returns to (1). In order to reduce the load, the control unit 7 does not convert the output values ​​of the current integration circuits 51 to 53 acquired in (2) into digital data by the A / D converters 61 to 63. (Operation when measurement is performed) When the control unit 7 receives a measurement operation command via the measurement operation command receiving means 94, it cancels the light amount restriction by the light amount control means 90 and starts exposure in step S41 of Fig. 6. Specifically, as shown in the timing chart of Fig. 7B, the light blocking means 91 is set to the fully open state and the light reducing means 92 is returned to the state at the time of the previous measurement.

[0072] Next, in step S42, the control unit 7 performs measurement according to the normal procedure. When performing measurement, the control unit 7 performs gain switching of the current integration circuits 51 to 53 and derives photometric conditions as necessary, and then performs integration (measurement).

[0073] In this embodiment, it is assumed that a display with a Vsync frequency of 60 Hz is being measured, and the exposure time is set to 1 / 30 [sec] (1 accumulation).

[0074] Integration is performed the number of measurements specified by the user. For example, if the user specifies 10 consecutive measurements and the number of integrations per measurement is 2, the number of integrations will be 2 x 10 = 20. Before measurement, the light amount limiting means 90 is activated to limit the amount of light reaching the optical sensors 41-43. Measurement is performed from this state, so errors due to residual charges in the current integration circuits 51-53 are suppressed.

[0075] Next, in step S43, the output value acquired by the measurement in step S42 is converted into a measurement index value (e.g., luminance value, chromaticity value). Specifically, the output value is subjected to zero calibration processing to calibrate offset errors, and then a normal output value conversion calculation process is performed to generate the target index value.

[0076] In step S44, after the specified measurement is completed, the control unit 7 activates the light amount limiting means 90 to prepare for the next measurement and to suppress errors due to residual charges.

[0077] In this embodiment, in order to improve the durability of each drive mechanism of the light quantity limiting means 90, which is composed of the shading means 91 and the dimming means 92, the operation of the light quantity limiting means 90 is set as follows, thereby dispersing the number of times the shading means 91 and the dimming means 92 operate.

[0078] That is, if the light attenuating means 92 is in a state of being withdrawn from the optical path at the time of measurement, the control unit 7 operates the light blocking means 91 to close the optical path (the state of the light attenuating means 92 remains unchanged).

[0079] On the other hand, if the light attenuating means 92 is inserted into the optical path during measurement, the control unit 7 maintains the inserted state of the light attenuating means 92 (the states of the light blocking means 91 and the light attenuating means 92 remain unchanged).

[0080] Note that the method for dispersing the number of times the light blocking means 91 and the light attenuation means 92 are activated is not limited to this. For example, the control unit 7 may switch between activating the light blocking means 91 and the light attenuation means 92 in order each time the light amount limiting means 90 is activated. Alternatively, the control unit 7 may switch between activating the light blocking means 91 and the light attenuation means 92 in accordance with the ratio of the number of times each of the light blocking means 91 and the light attenuation means 92 is activated. For example, if the number of times the light blocking means 91 is activated is twice the number of times the light attenuation means 92 is activated, the activation may be repeated in the order of the light attenuation means 92, the light attenuation means 92, and the light blocking means 91.

[0081] After completing step S44, the display light measurement device 1 transitions to a standby state (step S03 in FIG. 2).

[0082] As described above, in this embodiment 1, the light amount limiting means 90 operates based on a trigger signal when the display light measurement device 1 is started, and limits the amount of light incident on the optical sensors 41-43. The light amount limiting means 90 also operates during standby, at the end of zero calibration, and at the end of measurement, and limits the amount of light incident on the optical sensors 41-43. Therefore, zero calibration and measurement are performed with the residual charge in the integration capacitors of the current integration circuits 51-53 eliminated. As a result, errors in zero calibration and measurement caused by the residual charge can be suppressed using a simple method. [Embodiment 2] This second embodiment is applied to a method (instant type) in which zero calibration is performed immediately before each optical measurement.

[0083] 8 shows a state transition diagram of the display light measurement device 1 in embodiment 2. In this embodiment 3, measurement is performed in step S04 immediately after zero calibration is performed in step S02.

[0084] 9 to 12 show flowcharts. The flowchart in Fig. 9 shows the operation at startup, the flowchart in Fig. 10 shows the operation at zero calibration, the flowchart in Fig. 11 shows the operation at measurement execution, and the flowchart in Fig. 12 shows the operation at shutdown of the display light measurement device 1.

[0085] The main differences from the above-described first embodiment are that the light amount limiting means 90 is activated when the display light measurement device 1 is stopped, and that zero calibration and measurement are processed continuously. In order to activate the light amount limiting means 90 when the display light measurement device 1 is stopped, in the second embodiment, a monostable ND filter is used as the dimming means 92. This monostable ND filter has a mechanism that applies a biasing force in the direction in which the ND filter is inserted into the optical path. When the supply of power to the display light measurement device 1 is stopped, the biasing force causes the dimming means 92 to be automatically inserted into the optical path.

[0086] In the following explanation, only the differences from the first embodiment will be mainly explained. (Operation when stopped) When the user operates the operation stop button or turns off the power to stop the operation of the display light measurement device 1, this is detected as a trigger signal by the trigger detection means. Based on the detection of the trigger signal, the control unit 7 activates the light amount limiting means 90 in step S51 of FIG.

[0087] For example, when the stop button is operated, if the power supply is maintained, the control unit 7 sends a control signal to the light quantity limiting means 90, such as the dimming means 92, to transition the dimming means 92 to a state where it is inserted into the optical path. If the power supply is cut off, such as when the power is turned off, the biasing force applied to the monostable dimming means 92 causes the dimming means 92 to be mechanically inserted into the optical path.

[0088] Next, in step S52, the control unit 7 performs a shutdown process in a predetermined order. If there is no power supply, the shutdown process is skipped. The details of the shutdown process are the same as those of the conventional process, so a description thereof will be omitted. (Startup behavior) This is basically the same as embodiment 1. However, since the light quantity limiting means 90 is already activated in the stopped state, as shown in the flowchart of Fig. 9, the process of activating the light quantity limiting means 90 in step S12 in the flowchart of Fig. 3 is not necessary. (Operation in standby mode) This is the same as the standby state operation of the first embodiment shown in the flowchart of Fig. 5. In other words, the light amount limiting means 90 is in operation. (Operation during zero calibration) This is the same as the first embodiment except for the following points: In the first embodiment, the light quantity limiting means 90 is activated in step S24 of Fig. 4. In this second embodiment, this is unnecessary because "measurement" is performed next, and is therefore omitted from the flowchart of Fig. 10. (Operation when measurement is performed) The operation is the same as that of the first embodiment except for the following points. That is, in the first embodiment, step S41 in the flowchart of Fig. 6 is "release of light quantity limiting means." In contrast, in this embodiment, the process continues from "zero calibration," so that in step S41 of the flowchart of Fig. 11, the process of opening the shutter (light quantity limiting means) 90 is performed.

[0089] In this embodiment 2, when the display light measurement device 1 is stopped, the light amount limiting means 90 is activated and limits the amount of light incident on the optical sensors 41-43. Furthermore, the activated state of the light amount limiting means 90 is maintained even after the display light measurement device 1 is started up. The activation of the light amount limiting means 90 is deactivated during measurement. Therefore, zero calibration and measurement are performed with the residual charge in the integration capacitors of the current integration circuits 51-53 eliminated. As a result, errors in zero calibration and measurement caused by the residual charge can be suppressed by a simple method. [Other embodiments] Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments. As another embodiment, the user may be able to select whether or not to activate the light quantity limiting means 90 at startup, after measurement, when shutting down, etc. For example, by enabling operation of the light quantity limiting means 90 only when high-precision measurement is required, the light quantity limiting means 90 will not be activated as in the past when low precision is required. This reduces the number of times the light quantity limiting means 90 is activated, thereby shortening the takt time and preventing wear on the drive mechanism of the light quantity limiting means 90.

[0090] Furthermore, although zero calibration is performed in the first and second embodiments, measurement may be performed without performing zero calibration. [Explanation of symbols]

[0091] 1. Display light measurement device 2. Concentration section 3 Optical path branching section 41~43 Optical sensor 51~53 Current integration circuit 61~63 A / D converter 7 Control Unit 8 Memory section 90 Light limiting means 91 Shading means 92 Light reduction means 93 Trigger detection means 94 Measurement operation command receiving means

Claims

1. An optical sensor; an integration circuit having an integration capacitor for accumulating the charge output from the photosensor; a light amount limiting means for limiting the amount of light entering the optical sensor; a trigger detection means for detecting a trigger signal that triggers the light amount limiting means to limit the amount of light; a receiving means for receiving a command to perform a measurement operation; a control means for operating the light amount limiting means to limit the amount of light based on the detection of a trigger signal by the trigger detecting means, and for releasing the light amount limiting by the light amount limiting means based on a measurement operation command received by the receiving means; A display light measurement device comprising:

2. 2. The display light measurement device according to claim 1, wherein the trigger signal is a signal generated as a trigger when a user performs an operation on the display light measurement device to activate the display light measurement device.

3. An optical sensor; an integration circuit having an integration capacitor for accumulating the charge output from the photosensor; a light amount limiting means for limiting the amount of light entering the optical sensor; a receiving means for receiving a command to perform a measurement operation; a control means for releasing the restriction imposed by the light amount restriction means based on the measurement operation command received by the receiving means, and for operating the light amount restriction means to restrict the light amount at the end of the measurement operation; A display light measurement device comprising:

4. An optical sensor; an integration circuit having an integration capacitor for accumulating the charge output from the photosensor; a light amount limiting means for limiting the amount of light entering the optical sensor; a trigger detection means for detecting a trigger signal that triggers the stop of operation of the display light measurement device; a receiving means for receiving a command to perform a measurement operation; a control means for releasing the restriction imposed by the light amount restriction means based on the measurement operation command received by the receiving means, and for operating the light amount restriction means to restrict the light amount based on detection of a trigger signal by the trigger detection means; A display light measurement device comprising:

5. 5. The display light measurement device according to claim 4, wherein the trigger signal is a signal generated as a trigger when a user performs an operation on the display light measurement device to stop the operation of the display light measurement device.

6. An optical sensor; an integration circuit having an integration capacitor for accumulating the charge output from the photosensor; a light amount limiting means for limiting the amount of light entering the optical sensor; a calibration means for performing zero calibration; a receiving means for receiving a command to perform a measurement operation; a control means for operating the light amount limiting means to limit the amount of light when a measurement operation performed based on the measurement operation command received by the receiving means is completed and when zero calibration is completed; A display light measurement device comprising:

7. An optical sensor; an integration circuit having an integration capacitor for accumulating the charge output from the photosensor; a light amount limiting means for limiting the amount of light entering the optical sensor; a calibration means for performing zero calibration; a receiving means for receiving a command to perform a measurement operation; a control means for acquiring a zero calibration value based on the measurement operation command received by the receiving means, and releasing the restriction imposed by the light amount restriction means upon completion of acquisition of the zero calibration value, and starting the measurement operation; A display light measurement device comprising:

8. The display light measurement device according to claim 1 or 4, wherein the control means releases the light quantity limit imposed by the light quantity limiting means based on the reception of the command by the reception means, and activates the light quantity limiting means to limit the light quantity at the end of the measurement operation.

9. 8. The display light measurement device according to claim 1, wherein the light amount limiting means is a plurality of means, and the control unit does not limit the light amount limiting operation and the limit release operation to a specific light amount limiting means.

10. 8. The display light measurement device according to claim 1, wherein a user can select whether or not the light amount limiting means limits the amount of light.

11. An optical sensor; an integration circuit having an integration capacitor for accumulating the charge output from the photosensor; a light amount limiting means for limiting the amount of light entering the optical sensor; A display light measurement device comprising: detecting a trigger signal that triggers the light amount limiting means to operate so as to limit the amount of light; Accepts a command to perform measurement operation, activating the light amount limiting means to limit the amount of light based on the detection of the trigger signal, and canceling the light amount limiting by the light amount limiting means based on the command; A display light measurement method comprising:

12. An optical sensor; an integration circuit having an integration capacitor for accumulating the charge output from the photosensor; a light amount limiting means for limiting the amount of light entering the optical sensor; A display light measurement device comprising: Accepts a command to perform measurement operation, releases the restriction imposed by the light amount restriction means based on the command, and activates the light amount restriction means to restrict the light amount at the end of the measurement operation; A display light measurement method comprising:

13. An optical sensor; an integration circuit having an integration capacitor for accumulating the charge output from the photosensor; a light amount limiting means for limiting the amount of light entering the optical sensor; A display light measurement device comprising: Detecting a trigger signal that triggers the stop of operation of the display light measurement device; Accepts a command to perform measurement operation, releasing the restriction imposed by the light amount restriction means based on the command, and activating the light amount restriction means to restrict the light amount based on detection of a trigger signal by the trigger detection means; A display light measurement method comprising:

14. An optical sensor; an integration circuit having an integration capacitor for accumulating the charge output from the photosensor; a light amount limiting means for limiting the amount of light entering the optical sensor; A display light measurement device comprising: Perform zero calibration, Accepts a command to perform measurement operation, activating the light amount limiting means to limit the amount of light at the end of the measurement operation performed based on the command and at the end of zero calibration; A display light measurement method comprising:

15. An optical sensor; an integration circuit having an integration capacitor for accumulating the charge output from the photosensor; a light amount limiting means for limiting the amount of light entering the optical sensor; A display light measurement device comprising: Perform zero calibration, Accepts a command to perform measurement operation, a zero calibration value is acquired based on the command, and when acquisition of the zero calibration value is completed, the restriction by the light amount restriction means is released and a measurement operation is started. A display light measurement method comprising:

16. An optical sensor; an integration circuit having an integration capacitor for accumulating the charge output from the photosensor; a light amount limiting means for limiting the amount of light entering the optical sensor; A computer of a display light measurement device equipped with detecting a trigger signal that triggers the light amount limiting means to operate so as to limit the amount of light; Accepts a command to perform measurement operation, activating the light amount limiting means to limit the amount of light based on the detection of the trigger signal, and canceling the light amount limiting by the light amount limiting means based on the command; A program for executing a process.

17. An optical sensor; an integration circuit having an integration capacitor for accumulating the charge output from the photosensor; a light amount limiting means for limiting the amount of light entering the optical sensor; A computer of a display light measurement device equipped with Accepts a command to perform measurement operation, releases the restriction imposed by the light amount restriction means based on the command, and activates the light amount restriction means to restrict the light amount at the end of the measurement operation; A program for executing a process.

18. An optical sensor; an integration circuit having an integration capacitor for accumulating the charge output from the photosensor; a light amount limiting means for limiting the amount of light entering the optical sensor; A computer of a display light measurement device equipped with Detecting a trigger signal that triggers the stop of operation of the display light measurement device; Accepts a command to perform measurement operation, releasing the restriction imposed by the light amount restriction means based on the command, and activating the light amount restriction means to restrict the light amount based on detection of a trigger signal by the trigger detection means; A program for executing a process.

19. An optical sensor; an integration circuit having an integration capacitor for accumulating the charge output from the photosensor; a light amount limiting means for limiting the amount of light entering the optical sensor; A computer of a display light measurement device equipped with Perform zero calibration, Accepts a command to perform measurement operation, activating the light amount limiting means to limit the amount of light at the end of the measurement operation performed based on the command and at the end of zero calibration; A program for executing a process.

20. An optical sensor; an integration circuit having an integration capacitor for accumulating the charge output from the photosensor; a light amount limiting means for limiting the amount of light entering the optical sensor; A computer of a display light measurement device equipped with Perform zero calibration, Accepts a command to perform measurement operation, a zero calibration value is acquired based on the command, and when acquisition of the zero calibration value is completed, the restriction by the light amount restriction means is released and a measurement operation is started. A program for executing a process.

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