Photometric apparatus, calibration system, calibration method, and computer program product

Abstract

Provided are a photometric device, a correction system, a correction method, and a computer program product which are capable of performing high-precision correction for suppressing errors caused by insertion and extraction of a dimming member into an optical path regardless of the light emission characteristics of a display. The present invention is provided with: a light-reducing member (40) disposed so as to be capable of being inserted into and removed from an optical path of light (2) to be measured from a display (1); and an acquisition means (17) that, in order to generate a correction coefficient that suppresses a measurement error between a state in which the light-reducing member is inserted into the optical path and a state in which the light-reducing member is not inserted, acquires a photometric value of the light to be measured in a state in which the light-reducing member is inserted into the optical path and a photometric value of the light to be measured in a state in which the light-reducing member is not inserted. The acquisition unit acquires a total of at least three photometric values obtained by photometry in each state when at least two or more switches are performed, including switching from a state in which the dimming member is inserted into the optical path to a state in which the dimming member is not inserted and switching from the state in which the dimming member is not inserted to the state in which the dimming member is inserted.

Description

Technical Field

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

[0002] As a photometric device as described above, there is known a device having the following Fig.12 As shown in FIG. 1 , a photometric device 100 includes a branching optical system 120 that branches the light to be measured 201 from a display 200 into a plurality of light beams (eg, Patent Document 1).

[0003] The photometric device includes an objective optical system 110 composed of a convex lens, etc., a branching optical system 120, and colorimetric optical systems 130 to 150. As an example, the branching optical system 120 uses a bundled fiber. The bundled fiber is a bundle of multiple bare optical fibers with small diameters, which are randomly branched into multiple fibers (for example, three corresponding to the three stimulus values ​​of the color function X, Y, and Z specified by CIE (International Commission on Illumination)) at the output end (exit), and multiple fibers are bundled each time. In addition, there is also a case where a diffuser is used as the branching optical system 12.

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

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

[0006] However, recently, displays with a wide dynamic range of brightness are used in smartphones, etc. Therefore, the photometric device 100 is required to have a performance that can measure from dark brightness to bright brightness when performing gamma inspection and adjustment.

[0007] In order to expand the dynamic range of the light measuring device 100, it is necessary to control the amount of received light according to the constraints of the photoelectric conversion capability of the light receiving sensor (saturation of the light receiving sensor) and the design conditions of the electrical processing units 161a to 161c. Therefore, it is considered to insert or remove a dimming component according to the brightness of the display 200 in the optical path of the measured light 201 emitted from the display 200 until it enters the light receiving sensor.

[0008] However, when the dimming component is inserted or removed in order to expand the dynamic range, a difference occurs in the measured value between the inserted state and the uninserted state.

[0009] Therefore, in order to eliminate the difference caused by the insertion and removal of the dimming component, it is considered to calibrate the light measuring device. Such calibration requires measuring light in two states: a state where the dimming component is inserted into the optical path of the light to be measured and a state where the dimming component is not inserted into the optical path of the light to be measured, and generating a correction coefficient using these measured light values.

[0010] When the light emission of the display is stable, specifically, when the light emission cycle is a fixed cycle and the light emission waveform is also constant, a correction coefficient that satisfies the required accuracy can be generated by simply measuring light in the above two states.

[0011] Prior art literature

[0012] Patent Literature

[0013] Patent Document 1: Japanese Patent No. 5454675 Summary of the invention

[0014] Problems to be solved by the invention

[0015] However, as described below, the inventors' studies have revealed that it is sometimes difficult to ensure sufficient accuracy of the correction coefficient for recent displays.

[0016] That is, Fig.13 As shown in (A) in the figure, the light emission waveform becomes more complex as the functions and performance of the display improve. For example, in the case of OLED (Organic Light-Emitting Diode) displays, in order to achieve faithful color reproduction, in grayscale control, light emission control that combines not only amplitude modulation but also pulse width modulation is adopted, and high-amplitude light emission with a complex waveform is becoming common. In particular, in pulse width modulation, multiple pulse light emission controls are performed during one frame (vertical synchronization period), and the light emission waveform is accelerated compared to the image update period, and the waveform is steep and has a high amplitude. In addition, Fig.13 In the waveform illustrated in (A) in FIG. 1 , the vertical axis represents the brightness value, the horizontal axis represents the time, and the vertical synchronization frequency Vsync is 60 Hz.

[0017] In addition, in recent years, displays with VRR (Variable Refresh Rate) functions have been developed. In these displays, the refresh rate is switched dynamically and non-periodically, and transient responses are observed in the luminous waveform starting from the switching point, making the luminous waveform increasingly complex.

[0018] And, if Fig.13(B) in the figure shows the change in brightness when the brightness value is measured with 1 / 60 seconds as one frame. The luminous waveform has instability such as the rising short-term drift shown by arrow S1 and the non-periodic step difference shown by arrow S2. Fig.13 In (B) in FIG. 1 , the vertical axis represents the brightness value error normalized by the average brightness value Lv, and the horizontal axis represents the frame number, that is, time.

[0019] Drift is a slow increase or decrease in brightness value over time. As time passes, the brightness value increases as shown by arrow S1. The main cause of drift is the heating of information equipment including displays. Non-periodic step difference is an irregular large change in brightness value. Non-periodic step difference is caused by complex reasons such as "temperature feedback" and "image data update cycle corresponding to VRR".

[0020] When such a precise display is used to perform calibration for the insertion and removal of the dimming component, the calibration value changes each time the calibration is performed. Therefore, the same linear characteristics cannot be obtained in the measured values ​​in the state where the dimming component is not inserted into the optical path and in the state where the dimming component is inserted into the optical path, and a step difference occurs in the measured values ​​due to the switching of the insertion and removal of the dimming component. As a result, it is known that the following problem occurs: although the dynamic range can be expanded by assembling the dimming component, it is impossible to achieve high-precision measurement in the high-brightness range when the dimming component is in the inserted state.

[0021] The present invention was made in view of such technical background, and its purpose is to provide a photometric device, a correction system, a correction method and a computer program product that can perform high-precision correction for suppressing errors caused by the insertion and removal of dimming components into the optical path regardless of the luminous characteristics of the display.

[0022] Means for solving problems

[0023] The above object is achieved by the following means.

[0024] (1) A light measuring device, characterized in that it comprises:

[0025] a light reduction component configured to be insertable and removable relative to an optical path of the light to be measured from the display; and

[0026] an acquisition unit for acquiring a photometric value of the light to be measured when the light dimming component is inserted into the optical path and a photometric value of the light to be measured when the light dimming component is not inserted, in order to generate a correction coefficient for suppressing a measurement error between a state where the light dimming component is inserted into the optical path and a state where the light dimming component is not inserted,

[0027] The acquisition unit acquires a total of at least three metering values ​​obtained by measuring light in each state when at least two or more switchings are performed, including switching from a state where the dimming component is inserted into the optical path to a state where it is not inserted and switching from a state where it is not inserted to a state where it is inserted, as metering values ​​for generating the correction coefficient.

[0028] (2) The photometric device according to item 1 above,

[0029] The device further includes a generating unit configured to generate the correction coefficient using the photometric value for generating the correction coefficient acquired by the acquiring unit.

[0030] (3) The photometric device according to item 1 or 2 above,

[0031] When there are a plurality of reference colors for calibration, at least one of the switching frequency and the photometric condition is changed in accordance with the reference colors.

[0032] (4) The photometric device according to item 1 or 2 above,

[0033] Photometric values ​​corresponding to each of a state in which the light reduction component is inserted into the optical path and a state in which the light reduction component is not inserted are generated based on the weighted average value.

[0034] (5) The photometric device according to item 1 or 2 above,

[0035] The user can specify the number of switching times.

[0036] (6) The photometric device according to item 1 or 2 above,

[0037] The acquisition unit acquires a photometric value when the dimming component is switched between insertion and removal in a state where a reference color is set.

[0038] (7) The photometric device according to item 1 or 2 above,

[0039] Before the acquisition unit acquires the light metering value, light prediction is performed and the saturation is notified to the user.

[0040] (8) The photometric device according to item 1 or 2 above,

[0041] The acquisition unit acquires the light measurement value starting from a state in which the light reduction component is not inserted into the optical path.

[0042] (9) A calibration system, characterized in that it comprises:

[0043] The light measuring device as described in the above item 1; and

[0044] The generating unit generates the correction coefficient using the photometric value for generating the correction coefficient acquired by the acquiring unit of the photometric device.

[0045] (10) The calibration system according to item 9 above,

[0046] When there are a plurality of reference colors for calibration, at least one of the switching frequency and the photometric condition is changed in accordance with the reference colors.

[0047] (11) The calibration system according to item 9 or 10 above,

[0048] Photometric values ​​corresponding to each of a state in which the light reduction component is inserted into the optical path and a state in which the light reduction component is not inserted are generated based on the weighted average value.

[0049] (12) The calibration system according to item 9 or 10 above,

[0050] The user can specify the number of switching times.

[0051] (13) The calibration system according to item 9 or 10 above,

[0052] The acquisition unit of the light measuring device acquires the light measuring value when the dimming component is switched between insertion and removal in a state where the reference color is set.

[0053] (14) The calibration system according to item 9 or 10 above,

[0054] Before the acquisition unit of the light metering device acquires the light measurement value, light prediction is performed and the saturation is notified to the user.

[0055] (15) The calibration system according to item 9 or 10 above,

[0056] The acquisition unit of the light measuring device acquires the light measurement value starting from a state in which the light reduction component is not inserted into the optical path.

[0057] (16) A calibration method, characterized in that it is a calibration method for calibrating a light measuring device having a light reduction component, wherein the light reduction component is arranged to be insertable and removable with respect to an optical path of light to be measured from a display,

[0058] The correction method:

[0059] The step of acquiring the light measurement value of the light to be measured when the light reduction component is inserted into the optical path and the light measurement value of the light to be measured when the light reduction component is not inserted is performed in order to generate a correction coefficient for suppressing the measurement error between the state where the light reduction component is inserted into the optical path and the state where the light reduction component is not inserted,

[0060] In the acquisition step, the acquisition unit acquires a total of at least three light measurement values ​​obtained by measuring light in each state when at least two or more switchings are performed, including switching from a state where the light reduction component is inserted into the optical path to a state where the light reduction component is not inserted and switching from a state where the light reduction component is not inserted to a state where the light reduction component is inserted.

[0061] A generation step is also performed to generate the correction coefficient using the acquired photometric value.

[0062] (17) A computer program product for causing a computer of a light measuring device having a light reduction component to execute the acquisition step, the light reduction component being configured to be insertable and removable with respect to an optical path of light to be measured from a display,

[0063] In the acquisition step, in order to generate a correction coefficient for suppressing a measurement error between a state where the dimming component is inserted into the optical path and a state where the dimming component is not inserted, a photometric value of the light to be measured is acquired when the dimming component is inserted into the optical path and a photometric value of the light to be measured is acquired when the dimming component is not inserted into the optical path.

[0064] The computer is caused to perform the following processing: in the acquisition step, a total of at least three or more light metering values ​​obtained by measuring light in each state when at least two or more switchings are performed, including switching from a state in which the dimming component is inserted into the optical path to a state in which the dimming component is not inserted and switching from a state in which the dimming component is not inserted to a state in which the dimming component is inserted, are acquired as light metering values ​​for generating the correction coefficient.

[0065] Effects of the Invention

[0066] According to the photometric device, correction system, and correction method of the present invention, in order to generate a correction coefficient, the photometric value of the light to be measured in the state where the dimming component is inserted into the optical path and the photometric value of the light to be measured in the state where the dimming component is not inserted are acquired. A total of at least three or more photometric values ​​obtained by photometry in each state including at least two or more switchings from the state where the dimming component is inserted into the optical path to the state where the dimming component is not inserted and from the state where the dimming component is not inserted to the state where the dimming component is inserted are acquired. The correction coefficient is generated using the acquired photometric values ​​when the at least two or more switchings are performed.

[0067] In this way, since the correction coefficient is generated using a total of at least three or more light measurement values ​​obtained by measuring light in each state when the switching is performed at least twice, at least two light measurement values ​​are obtained for at least one of the light measurement value of the light to be measured in the state where the dimming component is inserted into the optical path and the light measurement value of the light to be measured in the state where the dimming component is not inserted. Therefore, by averaging the at least two light measurement values, even if Fig.13The light measurement values ​​on both sides of the step difference across the non-periodic step difference shown in (B) in the figure can also suppress the influence of the non-periodic step difference. As a result, regardless of the luminous characteristics of the display, a more accurate correction coefficient can be generated, and a more accurate measurement result can be obtained in the high brightness domain where the dimming component is inserted. In addition, the continuity of the straight line of the measured value can be ensured in the brightness value of the plug-in and unplugging of the dimming component.

[0068] The computer program product of the present invention can cause a computer of a photometric device to execute processing for acquiring at least three photometric values ​​in total obtained by photometry in each state when switching is performed at least twice as photometric values ​​for generating correction coefficients. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] Figure 1 It is an overall configuration diagram of a correction system according to a first embodiment of the present invention.

[0070] Figure 2 It is a block diagram showing the internal structure of the light measuring device.

[0071] Figure 3 It is a block diagram showing the structure of the control unit.

[0072] Figure 4 Is used to illustrate the Figure 1 A flow chart of the ND correction method performed by the correction system shown.

[0073] Figure 5 This is a table showing an example of photometric conditions during ND correction in this embodiment.

[0074] Figure 6 is with Fig.13 (B) in the same figure depicts a diagram of the timing of obtaining the photometric value.

[0075] Figure 7 This is a diagram for explaining the measurement error remaining after ND correction.

[0076] Figure 8 (A) is a diagram showing the measurement error in the conventional method. Figure 8 (B) in FIG. 1 is a diagram showing the measurement error of the first embodiment.

[0077] Fig. 9 It is an overall configuration diagram of a correction system according to a second embodiment of the present invention.

[0078] Fig.10 Is used to illustrate the Fig. 9 A flow chart of a method of ND correction performed by the correction system shown.

[0079] Fig.11 It is an overall structural diagram of a correction system involved in another embodiment of the invention.

[0080] Fig.12 This is a diagram showing the structure of a general three-stimulus value type photometric device.

[0081] Fig.13 (A) is a diagram showing an example of a light emission waveform of a display. Fig.13 (B) in the figure is a diagram showing short-term drift and non-periodic step differences in the luminous waveform. DETAILED DESCRIPTION

[0082] Hereinafter, embodiments of the present invention will be described based on the drawings.

[0083] [First embodiment]

[0084] In this embodiment, an example is described in which a correction application is used in a tristimulus value type photometry device to perform correction (matrix correction) for the insertion and removal of a dimming component on four display colors, namely, W (white), R (red), G (green), and B (blue). In the following description, the correction application is also referred to as a "correction application", and the correction for suppressing the error caused by the insertion and removal of the dimming component is also referred to as "ND correction". In addition, a state related to whether a dimming component is inserted or not inserted into the optical path of the measured light is also referred to as an "ND state", the inserted state is also referred to as an "ND state", and the non-inserted state is also referred to as a "non-ND state".

[0085] Figure 1 1 is an overall configuration diagram of a calibration system according to a first embodiment of the present invention. The calibration system includes a photometric device 10 , an information processing device 300 such as a personal computer, and a display 1 .

[0086] The information processing device 300 controls the entire correction system. Specifically, when performing ND correction, based on the correction application, the information processing device 300 communicates with the display 1 and the photometric device 10, controls the light emission state of the display 1, and causes the photometric device 10 to obtain the photometric value for generating the correction coefficient, so as to generate the correction coefficient by calculation.

[0087] Figure 2 2 is a block diagram showing the internal structure of the photometric device 10 .

[0088] exist Figure 2 In the present invention, for example, the photometric device 10 is used in an inspection process of a production line of a display of a smartphone to measure brightness, chromaticity, etc. of a display surface of the display 1 .

[0089] The photometric device 10 includes an objective optical system 11, a branching optical system 12, colorimetric optical systems 13 to 15, and a light reduction component 40. The objective optical system 11 uses a convex lens 11a having positive refractive power. The branching optical system 12 uses a diffuser plate 20 having branching and diffusion functions. In addition, a diffuser plate 20 may be used instead of the diffuser plate 20. Fig.12 As shown, the optical fiber has a branched bundle on the emission end side.

[0090] The aperture stop 11b is arranged at the rear focal position of the convex lens 11a to obtain components within ±2.5 degrees of the normal line of the display surface of the display 1, i.e., the measured surface, so as to form a front telecentric optical arrangement. The diffuser 20 is arranged at the rear of the aperture stop 11b.

[0091] A dimming member 40 is disposed between the convex lens 11a and the diffuser 20, that is, in front of the aperture stop 11b surface. The dimming member 40 is driven by an insertion and extraction device 50 as a driving device to be inserted into or withdrawn from the optical path of the light 2 to be measured. The insertion and extraction device 50 is composed of, for example, a linear actuator. When the dimming member 40 is inserted into the optical path of the light 2 to be measured, the amount of the light 2 to be measured incident on the diffuser 20 is reduced by the dimming member 40. When the dimming member 40 is withdrawn from the optical path of the light 2 to be measured, the amount of the light 2 to be measured is not reduced and is incident on the diffuser 20.

[0092] The dimming member 40 is inserted or removed according to the brightness of the display 1. Specifically, it is in a retracted state when the display 1 is dark, and is inserted into the optical path when the display 1 is bright, thereby reducing the amount of light to prevent the saturation of the light receiving sensors 13b, 14b, and 15b. As a result, the intensity of the measured light 2 can be set within the dynamic range of the light receiving sensors 13b, 14b, and 15b, and as a result, the dynamic range of the light measuring device 10 is expanded.

[0093] Preferably, the dimming component 40 is arranged near the focusing position (the position of the aperture stop 11b) of the objective optical system 11. In the light receiving optical path of the measured light 2, the effective optical path at the aperture stop position is smaller. The smaller the effective optical path, the smaller the size of the dimming component 40 can be, the smaller the plug-in device 50 can be, and the driving torque can also be low torque. Therefore, the product size becomes compact, light, and the cost becomes cheap. In addition, the aperture stop 11b may not be provided.

[0094] The dimming component 40 can be made of various filters such as a thin film filter, a glass absorption filter, a porous plate, etc. However, a thin film filter has good flatness in spectral transmittance and high reliability based on ambient temperature. Therefore, it is better to use a thin film filter as the dimming component 40.

[0095] The colorimetric optical systems 13, 14, 15 include wavelength selection filters 13a, 14a, 15a as isochromatic function filters corresponding to the tristimulus values ​​of X, Y, and Z, respectively, and light receiving sensors 13b, 14b, 15b as light receiving elements used in combination with the wavelength selection filters 13a, 14a, 15a.

[0096] The light received by each light receiving sensor 13b, 14b, 15b is converted into an electric signal, and after being processed by the corresponding electric processing unit 16a, 16b, 16b such as I / V conversion and amplification, it is input as light receiving data to the control unit 17. The control unit 17 performs calculations based on the input light receiving data to calculate a measurement value.

[0097] Furthermore, the light measuring device 10 includes a display unit 10b and an operating unit 10c. The display unit 10b displays an operation screen, a message, etc. The operating unit 10c is used to operate the light measuring device 10, and may be composed of a touch panel of the display unit 10b, an operating button provided in the housing of the light measuring device 10, or both.

[0098] Figure 3 1 shows the configuration of the control unit 17. The control unit 17 includes a CPU 171, a ROM 172, a RAM 173, a storage unit 174, and the like.

[0099] The CPU 171 operates according to the operation program, thereby controlling the entire photometric device 10 in a unified manner. For example, when measuring the display 1, the CPU 171 receives signals from the electrical processing units 16a to 16c, performs correction using the correction coefficient as needed, and calculates the final measurement value. In addition, in this embodiment, when the ND calibration is performed at the factory before shipment, or when the ND calibration is performed according to the user's instructions after shipment, the photometric value for generating the correction coefficient is obtained in the state where the dimming component 40 is inserted into the optical path of the measured light 2, and the state where the dimming component 40 is not inserted into the optical path of the measured light 2, and the ND correction count is generated using the obtained photometric value, but the details will be described later.

[0100] The ROM 172 is a memory for storing predetermined setting values ​​and other data. The RAM 173 is a memory for providing a work area when the CPU 171 operates according to an operation program.

[0101] The storage unit 174 is composed of a storage medium such as a hard disk device and an SSD, and stores various data and applications such as the action program of the CPU 171, the metering value for generating the ND correction coefficient, the generated ND correction coefficient, and the measured values ​​of brightness, chromaticity, etc. corrected using the correction coefficient.

[0102] Next, refer to Figure 4 Flow chart of Figure 1The ND correction method performed by the correction system shown in FIG. 1 is described below. The operation of the information processing device 300 by the user U is performed based on the signal sent and received between the information processing device 300 and the display 1 or the light measuring device 10. Figure 4 As the display 1, for example, a reference display having a light source for calibration is used.

[0103] If the user U instructs the information processing device 300 to shift to the ND correction mode in step u10 , the information processing device 300 instructs the photometric device 10 to shift to the ND correction mode in step s10 , and the photometric device 10 accepts the correction mode in step i10 .

[0104] In step s20, the information processing device 300 controls the correction light source of the display 1, and in step d20, causes the display 1 to display a color of a preset reference value (RGB grayscale, brightness). In the present embodiment, the display color is any one of WRGB.

[0105] Next, in step s30, when the information processing device 300 sends an instruction to execute the predicted light to the light measuring device 10, the light measuring device 10 measures the predicted light value in step i30. The purpose of the predicted light is to optimize the light measuring conditions when "executing the reference color measurement" in step s50. If it is not necessary, it may not be performed.

[0106] However, the light emitting waveform of the display 1 is as follows Fig.13 The non-periodic characteristics (e.g., the interval between non-periodic steps and the amount of steps) vary according to each reference value (each WRGB) during ND correction. Furthermore, there are individual deviations.

[0107] By predicting the light intensity and waveform, the pulsation (ratio of peak intensity to average intensity) and instability (drift, non-periodic step difference) of the light emission can be obtained. In addition, the photometric conditions are derived based on the acquired predicted light information. An example is given below.

[0108] (1) The exposure time for ensuring the S / N ratio is calculated based on the average intensity obtained by the predicted light. Since the amount of incident light to the light receiving sensors 13b, 14b, and 15b differs depending on whether the dimming component 40 is inserted or removed, the exposure time is calculated based on the state in which the dimming component 40 is inserted or not inserted into the optical path, in other words, based on each ND state.

[0109] (2) Based on the peak intensity obtained by the prediction light, the circuit gain for avoiding saturation is determined for each ND state.

[0110] (3) Based on the instability obtained by predicting the light, the number of times the dimming component is inserted and removed to suppress the non-periodic step difference is calculated.

[0111] Furthermore, the saturation can be derived based on the predicted light information and notified to the user U. Here, the saturation is an index indicating the ratio of the actual measured intensity to the luminous intensity capable of ND correction. The luminous intensity capable of ND correction is the intensity that can be measured without saturation of the light receiving sensor when the dimming component 40 is not inserted into the optical path. It is also correlated with instability (e.g., step difference).

[0112] By notifying the user U of the saturation, the following effects are achieved.

[0113] That is, the display condition in which the saturation is 100% or less and as large as possible can more effectively utilize the dynamic range of the photometric device 10, so the correction accuracy can be improved.

[0114] In addition, since saturation is also correlated with instability, it is possible to make use of the saturation to control the quality of the display 1 and provide feedback on the design, etc.

[0115] Furthermore, in this step, the vertical synchronization frequency Vsync of the display 1 can be derived. In this case, the user U does not need to bother setting the vertical synchronization frequency Vsync.

[0116] In step u40, the user U confirms the saturation notified from the light measuring device 10. If the saturation is judged to be inappropriate (for example, more than 100%, less than 10%, etc.), the process may be forced to end. Alternatively, the process may return to the correction light source control of step s20 to change the control display conditions.

[0117] If the saturation is appropriate, the information processing device 300 is instructed to measure the reference color. In response to the instruction, in step s50 , the information processing device 300 instructs the photometric device 10 to measure the reference color.

[0118] In step i50, the light measuring device 10 that has received the instruction grasps the state (ND state) of the light reduction component 40, in other words, grasps the state in which the light reduction component 40 is inserted into the optical path or the state in which the light reduction component 40 is not inserted into the optical path. Furthermore, when either the state in which the light reduction component 40 is inserted into the optical path or the state in which the light reduction component 40 is not inserted into the optical path is set as ND state A, and the other is set as ND state B, in step i51, the light measurement value is measured and acquired in ND state A. Next, in step i52, the light measurement value is measured and acquired in ND state B. Basically, light measurement is performed at an integral multiple of the vertical synchronization period Tsync=1 / Vsync.

[0119] In step i53, it is determined whether the number of switchings including the switching from ND state B to ND state A and the switching from ND state A to ND state B has reached a predetermined number of 2 or more. In this embodiment, the switching from ND state A to ND state B and the switching from ND state B to ND state A are each regarded as one switching and the number of switchings is counted. Therefore, for example, when the dimming component 40 is inserted into the optical path and withdrawn from the optical path, the number of switchings is 1, and when it is inserted again, the total number of switchings is counted as 2, and thereafter, the number of switchings is incremented by 1 each time the withdrawal or insertion is performed.

[0120] In step i53, if the switching frequency does not reach the prescribed frequency of 2 or more (step i53: NO), the process returns to step i51 to switch the ND state and measure light. If the switching frequency reaches the prescribed frequency (step i53: YES), the process proceeds to step i54.

[0121] In addition, Figure 4 In the flowchart, if the number of switching times does not reach the specified number, the metering of ND state A and the metering of ND state B are performed, so the number of metering values ​​of ND state A and the number of metering values ​​of ND state B are the same. For example, when the number of switching times is 3 times, the metering of ND state A → switching → metering of ND state B → switching → metering of ND state A → switching → metering of ND state B are performed, and the number of metering values ​​of ND state A is 2, and the number of metering values ​​of ND state B is 2.

[0122] However, the numbers of the two metering values ​​may be different. For example, the number of switching times may be set to 2, and metering in ND state A → switching → metering in ND state B → switching → metering in ND state A may be performed, and the number of metering values ​​in ND state A is 2, and the number of metering values ​​in ND state B is 1, which is 3 in total. In addition, for example, the number of switching times may be set to 4, and the number of metering values ​​in ND state A is set to 3, and the number of metering values ​​in ND state B is set to 2.

[0123] In short, as long as switching is performed twice or more, either the light metering value in ND state A or the light metering value in ND state B is 2 or more, and the other is 1 or more, a total of 3 or more light metering values ​​can be obtained.

[0124] Return to Figure 4 In the flowchart, in step i54, the light metering values ​​acquired in each ND state A and ND state B are averaged, and the averaged value is used as the light metering value in each ND state for generating the correction coefficient.

[0125] In this embodiment, as described above, the average is simply used to generate the light measurement value for each ND state. However, if the following processing is provided, the influence of instability is further reduced and the accuracy is improved.

[0126] That is, outlier exclusion processing is performed, for example, discontinuous points are extracted from the time series and the positions are excluded, or outliers of spikes are extracted and excluded.

[0127] In addition, the average is weighted. For example, in a time series, the drift amount is detected, and each measured value is weighted and averaged according to the degree of change.

[0128] In addition, in the present embodiment, the number of times of switching the dimming member 40 by plugging and unplugging is determined by the predicted light, but a mode in which the number of times can be specified by the user U may be provided. For example, in the case of calibration of the display 1 using a stable light source, by setting the number of switching times to 1, there is an effect that the calibration time can be shortened, and it can be used separately according to the display 1 used. In addition, the user U can control the calibration time (number of times) and accuracy by himself.

[0129] In addition, the light measuring device 10 itself performs steps i50 to 54, but the present invention is not limited to this. For example, the information processing device 300 may manage and control the steps.

[0130] In step s60, the information processing device 300 checks whether the acquisition of the photometric values ​​for the four colors of WRGB is completed. If not completed (step s60: NO), the process returns to step s20 and controls the display 1 to emit light in other reference colors.

[0131] In this way, the ND state is switched for each reference color to perform light measurement, but as a switching method, there are a reference color priority method and an ND state priority method. The reference color priority method is a method of switching the ND state with a fixed reference color, and when the light measurement of one reference color is completed, the ND state is switched for the next reference color. On the other hand, the ND state priority method is a method of switching the reference color for light measurement with a fixed ND state (for example, ND state A), and when the light measurement of ND state A is completed, it is switched to ND state B and fixed, and the reference color is switched for light measurement.

[0132] In this embodiment, a reference color priority method is adopted, and the reference color priority method has the following effects.

[0133] That is, the time difference between the data of each ND state is short, so that the calibration error caused by drift can be suppressed. In addition, since the data of each ND state is continuous in time series, the influence of the step difference can be suppressed by averaging even across non-periodicity.

[0134] On the other hand, the ND state priority method can also be expected to improve the accuracy of ND calibration. This ND state priority method is preferred because it can shorten the calibration time for a measuring instrument having a long ND state switching time.

[0135] Return to Figure 4 , when the acquisition of all the metering values ​​for the four colors is completed (step s60: YES), in step s70, the acquisition instruction of the ND correction coefficient is sent to the metering device 10, and in step i70, the metering device 10 generates the ND correction coefficient.

[0136] When the tristimulus values ​​calculated from the photometric values ​​in a state where the light reduction member 40 is inserted into the optical path are taken as S 1(W,R,G,B) , the tristimulus values ​​calculated based on the photometric values ​​when the dimming component 40 is not inserted into the optical path are set as S 2(W,R,G,B) When S is generated, 2(WRGB) ≒N·S 1(WRGB) ND correction factor N.

[0137] The ND correction coefficient may be a correction count for correcting the error caused by the insertion and removal of the light reduction component 40, and may be a correction coefficient generated using the photometric values ​​of each of the state where the light reduction component 40 is inserted into the optical path and the state where the light reduction component 40 is not inserted into the optical path. In addition, the ND correction may be either a factory correction performed at the factory or a user correction performed based on an instruction of the user U of the light measuring device 10.

[0138] In step s80 , the information processing device 300 issues a recording instruction of the ND correction coefficient to the photometric device 10 , and then terminates the control process in step s99 . The photometric device 10 that receives the recording instruction of the ND correction coefficient stores the generated ND correction coefficient in the storage unit 140 in step s80 .

[0139] In addition, in this embodiment, the photometric device 1 generates the ND correction coefficient, but the information processing device 300 may obtain the photometric value of each ND state from the photometric device 10, generate the ND correction coefficient, and send the generated ND correction coefficient to the photometric device 10 and store it.

[0140] When the measured light of the display 1 is actually measured, the obtained photometric value is corrected using the ND correction coefficient stored in the storage unit 174 to obtain a final measured value.

[0141] Figure 5 : is a table showing an example of the photometric conditions during ND correction in this embodiment. Figure 5 In the table shown, the light waveform of the reference color G (green) is Fig.13 The stability of the waveform shown in (A) is the same as that shown in (B) of the same figure. Different conditions are set for exposure time, switching times, etc. according to the reference color.

[0142] Next, taking the base color green as an example, refer to Figure 6 to Figure 8 , the effects of this embodiment are explained.

[0143] Figure 6 is with Fig.13 The same figure as (B) in FIG. 1 depicts the timing of obtaining the light measurement value. In addition, the insertion and removal control time of the light reduction component 40 of the light measurement device 10 used for measurement is about 20 msec. Therefore, the light measurement values ​​of ND state A and ND state B obtained in the light measurement device 10 are the same as those of the light measurement device 10. Figure 6 The metered values ​​shown are approximately the same if about 1 point is skipped.

[0144] according to Figure 5 , for the reference color green, the ND state A and the ND state B were switched 11 times for measurement. Figure 6 The 0 mark is the measured value of ND state A, and the △ mark is the measured value of ND state B. By skipping about 1 point, 6 metering values ​​are obtained for each of the ND state A and ND state B, a total of 12 light measurement values ​​are obtained. The combination of the first black 0 mark and the next black △ mark indicates that the ND correction coefficient is generated by only one switching, which is recorded as a conventional example.

[0145] When ND correction is performed based on the metered value obtained by this one switching, Figure 6 As shown, when the light measurement value is occasionally obtained across a non-periodic step difference during calibration, a large error is generated.

[0146] On the other hand, in the correction system of the present embodiment, even across a non-periodic step difference, by switching ND state A and ND state B more than twice (11 times in this example), measuring multiple values ​​(6 each in this example), and using the average value of each value as the metering value, the error can be greatly reduced.

[0147] This effect is explained using the measurement error remaining after ND correction, in other words, the insertion and removal error amount of the light reduction component 40. Here, the insertion and removal error amount of the light reduction component 40 is as follows: Figure 7 As shown in the figure, in the high brightness domain (in Figure 7 The state in which the dimming component 40 is inserted in the low brightness region (in the Figure 7 The relative error amount (in Figure 7 ND insertion error).

[0148] Figure 8 (A) in FIG. 1 shows the ND insertion error when the ND correction is performed by the conventional method. In this evaluation, a series of operations of obtaining the ND correction value coefficient from each photometric value with the conventional switching frequency of 1 and obtaining the ND insertion error using the generated correction coefficient were repeated 50 times. Figure 8 (A) in FIG. 1 is a graph depicting the ND insertion and removal error at each time when 50 calibrations are performed. On the other hand, Figure 8 (B) in the figure shows the ND insertion error each time when 50 calibrations were performed in the ND calibration in which the ND correction value coefficient was obtained from 6 light measurement values ​​each time, with the switching number being 11 in the present embodiment.

[0149] Figure 8 (A) and Figure 8 The (B) in the figure indicates the ND insertion and removal error generated during each calibration. Figure 8 (A) and Figure 8 From the comparison of (B) in FIG. 1 , it can be seen that the present embodiment suppresses the ND insertion error and converges within the allowable range shown by the dotted line in the figure. In addition, it can be seen that since the deviation of the ND insertion error of the present embodiment is small, it is stable. Therefore, it is possible to generate a high-precision correction coefficient with good reproducibility.

[0150] Furthermore, even if the ND state A and the ND state B are continued, for example, after the light is continuously measured in the ND state A for 6 cycles of the vertical synchronization signal, the state A is switched to the ND state B, and the light is continuously measured and the ND correction is performed during the same period, the error reduction effect of the present embodiment cannot be expected. In other words, even if the total exposure time is simply increased by the same amount as in the present embodiment, the averaging effect is low.

[0151] If the number of switching times between ND state A and ND state B is set as follows, both "improvement of ND correction accuracy" and "reduction of correction time" can be achieved. That is, the time is set as long as possible so that the non-periodic step difference enters once within the total exposure time for ND correction.

[0152] [Second embodiment]

[0153] Fig. 9 1 is an overall configuration diagram of a correction system according to a second embodiment of the present invention. The correction system includes a photometric device 10 and a display 1. A user directly controls the display 1 and the photometric device 10 to perform ND correction (matrix correction) on four display colors WRGB.

[0154] The structure of the light measuring device 10 is Figure 1 The photometric device 10 in the illustrated embodiment 1 is the same as that in the illustrated embodiment 1, and therefore its description is omitted.

[0155] Next, refer to Fig.10 Flow chart of Fig. 9 The ND correction method performed by the correction system shown in FIG. Fig.10 As the display 1, for example, a reference display serving as a light source for calibration is used.

[0156] If the user U instructs the photometric device 10 to shift to the ND correction mode in step u10 , the photometric device 10 accepts the ND correction mode in step s10 .

[0157] In step u20, user U controls the calibration light source (display 1), and in step d20, displays the color of the preset reference value (RGB grayscale, brightness) on the display 1. The brightness is preferably set to a predetermined recommended intensity range. The recommended intensity is determined based on the S / N and dynamic range of the system.

[0158] In step u30, the user U notifies the light measuring device 10 of the display color, and in step s30, the light measuring device 10 receives the notification of the display color. In addition, the light measuring device 10 may also have a function of identifying the display color based on the light measurement value instead of notifying the display color. For example, in the case where the light measuring device 10 is a tristimulus value type, it can be easily identified based on the acquired XYZ balance. The identification of the display color eliminates operational errors, thereby improving usability.

[0159] In addition, it is preferable that the photometric device 10 has a function of selectively receiving the display intensity. By having the intensity information in advance, photometry under appropriate conditions can be performed, and the correction accuracy is improved. On the other hand, since the user's setting becomes complicated, it is not essential.

[0160] Then, in step u40, the user U instructs the light measuring device 10 to perform the measurement of the reference color. The notification of the display color in step u30 may be performed simultaneously with the measurement execution instruction in step u40. The light measuring device 10 that has received the instruction grasps the ND state of the dimming component 40 in step s40, in other words, whether the dimming component 40 is inserted into the optical path or not. And, if the dimming component 40 is inserted into the optical path (ND state), it is changed to the not-inserted state. If it is not-inserted state (ND state), it remains as it is.

[0161] By setting the ND-free state, the following effects are achieved. That is, since the ND state is switched twice, the ND state for initial light measurement increases to two times. Therefore, light measurement is initially performed for the one with a shorter exposure time (in the ND-free state, the amount of light is larger), which has the advantage of shortening the correction time. In addition, by first performing light measurement for the ND-free state, the accuracy of judging the appropriateness of the light source's luminous intensity is also improved. However, it is also possible not to change to the ND-free state, but to just stay in the grasp of the ND state.

[0162] Next, in steps s41 to s43, the light measuring device 10 switches the ND state twice to measure and acquire the light measurement value. Basically, light measurement is performed at an integral multiple of the vertical synchronization period Tsync=1 / Vsync.

[0163] Next, in step s44, the photometric value obtained for each ND state is used as the photometric value for each ND state used for generating the correction coefficient. In addition, the ND states measured twice are averaged and used as the photometric value.

[0164] In step u50 , the user U checks whether the acquisition of the photometric values ​​for the four colors of WRGB is completed. If not completed (step u50 : NO), the process returns to step u20 and controls the display 1 to emit light of other reference colors.

[0165] When the acquisition of the photometric values ​​of all four colors is completed (step u50 : YES), in step u60 , an acquisition command of the ND correction coefficient is sent to the photometric device 10 , and in step s60 , the photometric device 10 generates the ND correction coefficient.

[0166] In step u70 , the user U instructs the photometric device 10 to record the ND correction coefficient, and then the control process ends in step u99 . In step s70 , the photometric device 10 , which has received the instruction to record the ND correction coefficient, stores the generated ND correction coefficient in the storage unit 140 .

[0167] According to the second embodiment, by switching the ND state twice, for example, when the drift changes linearly, the average of the two light measurement values ​​in the ND state A is consistent with the ND state B, so that the ND correction error caused by the instability caused by the drift can be suppressed. Therefore, it is possible to achieve both shortening the ND correction time and improving the correction accuracy.

[0168] As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment.

[0169] For example, Fig.11As shown, a calibration application may be installed and incorporated in the display 1 provided with a calibration light source, and the photometric device 10 may be controlled by the calibration application during ND calibration.

[0170] Furthermore, although the ND correction in the case of four colors (WRGB) has been described, the present invention is not limited to this, and for example, a single-point correction of only W (white) may be used.

[0171] Description of Reference Numerals

[0172] 1 display; 2 measured light; 10 photometric device; 10b display unit; 10c operating unit; 11 objective optical system; 11a convex lens; 11b aperture stop; 12 branching optical system; 13-15 colorimetric optical system; 13a, 14a, 15a wavelength selection filter; 13b, 14b, 15b light receiving sensor; 16, 16a-16c electrical processing unit; 17 control unit; 20 diffusion plate; 40 light reduction component; 41 transparent plate; 41a incident surface; 41b exit surface; 42, 43 thin films; 50 plug-in device; 300 information processing device.

Claims

1. A light measuring device, characterized in that: have: a light reduction component configured to be insertable and removable relative to an optical path of the light to be measured from the display; as well as an acquisition unit, for generating a correction coefficient for suppressing a measurement error between a state in which the dimming component is inserted into the optical path and a state in which the dimming component is not inserted into the optical path, by acquiring a photometric value of the light to be measured in a state in which the dimming component is inserted into the optical path and a photometric value of the light to be measured in a state in which the dimming component is not inserted into the optical path, The acquisition unit acquires a total of at least three metering values ​​obtained by measuring light in each state when at least two or more switchings are performed, including switching from a state in which the dimming component is inserted into the optical path to a state in which the dimming component is not inserted into the optical path and switching from a state in which the dimming component is not inserted into the optical path to a state in which the dimming component is inserted into the optical path, as metering values ​​for generating the correction coefficient.

2. The light measuring device according to claim 1, wherein: The device further includes a generating unit configured to generate the correction coefficient using the photometric value for generating the correction coefficient acquired by the acquiring unit.

3. The light measuring device according to claim 1 or 2, wherein: When there are a plurality of reference colors for calibration, at least one of the switching frequency and the photometric condition is changed in accordance with the reference colors.

4. The light measuring device according to claim 1 or 2, wherein: Photometric values ​​corresponding to each of a state in which the light reduction member is inserted into the optical path and a state in which the light reduction member is not inserted into the optical path are generated based on the weighted average value.

5. The light measuring device according to claim 1 or 2, wherein: The user can specify the number of switching times.

6. The light measuring device according to claim 1 or 2, wherein: The acquisition unit acquires a photometric value when the dimming component is switched between insertion and removal in a state where a reference color is set.

7. The light measuring device according to claim 1 or 2, wherein: Before the acquisition unit acquires the light metering value, light prediction is performed and the saturation is notified to the user.

8. The light measuring device according to claim 1 or 2, wherein: The acquisition unit acquires the light measurement value starting from a state in which the light reduction component is not inserted into the optical path.

9. A correction system, characterized in that: have: The light measuring device according to claim 1; and The generating unit generates the correction coefficient using the photometric value for generating the correction coefficient acquired by the acquiring unit of the photometric device.

10. The correction system of claim 9, wherein: When there are a plurality of reference colors for calibration, at least one of the switching frequency and the photometric condition is changed in accordance with the reference colors.

11. The correction system according to claim 9 or 10, wherein: Photometric values ​​corresponding to each of a state in which the light reduction member is inserted into the optical path and a state in which the light reduction member is not inserted into the optical path are generated based on the weighted average value.

12. The correction system according to claim 9 or 10, wherein: The user can specify the number of switching times.

13. The correction system according to claim 9 or 10, wherein: The acquisition unit of the light measuring device acquires the light measuring value when the dimming component is switched between insertion and removal in a state where the reference color is set.

14. The correction system according to claim 9 or 10, wherein: Before the acquisition unit of the light metering device acquires the light measurement value, light prediction is performed and the saturation is notified to the user.

15. The correction system according to claim 9 or 10, wherein: The acquisition unit of the light measuring device acquires the light measurement value starting from a state in which the light reduction component is not inserted into the optical path.

16. A calibration method, characterized in that: The present invention is a correction method for calibrating a light measuring device having a light reduction component, wherein the light reduction component is configured to be insertable and removable with respect to an optical path of light to be measured from a display. The correction method: The step of acquiring is performed to generate a correction coefficient for suppressing a measurement error between a state in which the dimming component is inserted into the optical path and a state in which the dimming component is not inserted into the optical path, by acquiring a photometric value of the light to be measured in a state in which the dimming component is inserted into the optical path and a photometric value of the light to be measured in a state in which the dimming component is not inserted into the optical path, In the acquisition step, the acquisition unit acquires a total of at least three or more light measurement values ​​obtained by measuring light in each state when at least two or more switchings are performed, including switching from a state where the light reduction component is inserted into the optical path to a state where the light reduction component is not inserted into the optical path and switching from a state where the light reduction component is not inserted into the optical path to a state where the light reduction component is inserted into the optical path. A generation step is also performed to generate the correction coefficient using the acquired photometric value.

17. A computer program product for causing a computer of a light measuring device having a light reduction component to execute an acquisition step, the light reduction component being configured to be insertable and removable with respect to an optical path of light to be measured from a display, In the acquisition step, in order to generate a correction coefficient for suppressing a measurement error between a state in which the dimming component is inserted into the optical path and a state in which the dimming component is not inserted into the optical path, a photometric value of the light to be measured in a state in which the dimming component is inserted into the optical path and a photometric value of the light to be measured in a state in which the dimming component is not inserted into the optical path are acquired, The computer program product is used to cause the computer to perform the following processing: in the acquisition step, a total of at least three or more light metering values ​​obtained by measuring light in each state when at least two or more switchings are performed, including switching from a state in which the dimming component is inserted into the optical path to a state in which the dimming component is not inserted into the optical path and switching from a state in which the dimming component is not inserted into the optical path to a state in which the dimming component is inserted into the optical path, are acquired as light metering values ​​for generating the correction coefficient.

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