JP4677399B2 - Liquid crystal display device, characteristic amount measuring device for liquid crystal display device, characteristic amount measuring method, and computer program - Google Patents

Description

  The present invention relates to a liquid crystal display device capable of measuring a characteristic amount such as luminance or chromaticity of a display surface of a liquid crystal panel for calibration or characteristic check, a characteristic amount measuring device for the liquid crystal display device, and a characteristic amount measurement The present invention relates to a method and a computer program.

  2. Description of the Related Art A liquid crystal display device that has been widely used in recent years is configured to include a liquid crystal panel in which a liquid crystal material is sealed between a pair of glass substrates, and a backlight disposed on the back of the liquid crystal panel. Alternatively, the video is displayed by driving the liquid crystal panel in accordance with a video signal given from an external device such as a playback device. The liquid crystal display device is equipped with a gate driver and a source driver as a driving circuit for the liquid crystal panel, and the gate driver and the source driver are connected to the gate and source of the transistor that drives each pixel of the liquid crystal panel, and the inputted video The on / off of the transistor is controlled based on the signal, and a voltage (input level to the liquid crystal panel) corresponding to the video signal is applied to the transistor controlled to be on, which is determined by the electro-optical characteristics of the liquid crystal substance. Change the light transmittance. As a result, the liquid crystal display device can display an image in gradation by controlling the amount of light emitted from the backlight and transmitted through the liquid crystal panel for each pixel.

  In the liquid crystal panel, the electro-optical characteristics of the liquid crystal material are determined by the facing distance between the glass substrates in which the liquid crystal material is sealed, the so-called liquid crystal gap, but due to factors such as manufacturing variations, the liquid crystal panel has a narrow and wide liquid crystal gap with respect to the design value. In some cases, the light transmittance of the liquid crystal panel deviates from the design value due to a mixture of pixels, and desired gradation characteristics cannot be obtained. As a countermeasure, a LUT (Look Up Table) in which a gradation level (gradation value) based on an input video signal and an input level to a liquid crystal panel corresponding to the gradation level are associated is stored in a memory or the like. By storing and converting the gradation level into the input level based on the LUT, the gradation characteristic specific to each liquid crystal display device is corrected to realize a desired gradation characteristic.

  However, characteristics of the liquid crystal panel, the backlight, and the like change with the use of the liquid crystal display device. For this reason, when aging has occurred, the desired gradation characteristics cannot be realized even if the gradation characteristics are corrected based on the LUT stored at the time of manufacture or shipment of the liquid crystal display device. There is a fear. This problem can be dealt with by performing a so-called calibration in which the LUT is updated on the user side after the liquid crystal display device is shipped.

  In Patent Document 1, image quality data detected by a photometry unit provided opposite to a liquid crystal display unit is measured, ideal ideal registered image quality data is stored in advance, and the measured image quality data and registered image quality are stored. There has been proposed a self-adjusting display system that extracts difference data from data and controls a liquid crystal display unit so that the difference data becomes a predetermined value or less. This self-adjusting display system has an advantage that the liquid crystal surface is not shielded except during photometry because the photometry unit can be accommodated in the bezel of the liquid crystal display device when photometry is not performed. In addition, since photometry can be performed without human intervention, there is an advantage that calibration can be performed by remote activation via a network or automatically when necessary.

  However, as in the self-adjusting display system described in Patent Document 1, when the photometric unit is housed in the bezel of the liquid crystal display device, the range in which photometry can be performed is only the peripheral portion of the liquid crystal display surface. . Since liquid crystal panels are more likely to have uneven brightness or color unevenness at the periphery of the display surface, display is performed with optimal gradation characteristics when calibration is performed based on the photometric results at the periphery of the display surface. There is a possibility that it cannot be done. Also in Patent Document 1, it is described that it is possible to perform photometry at the center of the display surface with a manual photometer, and to correlate it with the photometry results at the peripheral part, but the detailed method is not mentioned.

The inventor of the present application has already proposed a technique for estimating the characteristic amount at the center of the display surface from the characteristic amount such as luminance acquired by the sensor at the periphery of the display surface of the liquid crystal panel. Briefly describe the technology. FIG. 12 is a schematic diagram for explaining one method for estimating the characteristic amount of the central portion from the characteristic amount of the peripheral portion of the display surface of the liquid crystal panel. In the figure, reference numeral 201 denotes a monochrome display liquid crystal display device, and a swing sensor 30 capable of automatically measuring the luminance of the peripheral portion of the display surface of the liquid crystal panel is mounted on the liquid crystal display device 201. In addition, an external light sensor 40 is provided for the user to manually measure the luminance at the center of the display surface, and the relative ratio between the measurement value of the swing sensor 30 and the measurement value of the external light sensor 40 is calculated as a relative ratio calculation unit. By calculating 200 based on the following equation (1), a relative ratio LUT as shown is created.
(Relative ratio) = (Measurement value of swing sensor) / (Measurement value of external light sensor) (1)

The relative ratio LUT illustrated as an example is for the case where the liquid crystal display device 201 can perform display with 256 gradations. In order to create this relative ratio LUT, it is necessary to switch the display on the display surface of the liquid crystal display device 201 in 256 steps for each gradation, and to perform measurement by the swing sensor 30 and the external light sensor 40 at each gradation. is there. When the liquid crystal display device 201 is calibrated, the measurement of only the swing sensor 30 is performed to obtain the measured value of the peripheral portion of the display surface, and the relative portion LUT is referred to thereby estimating the central portion of the display surface. A measurement value can be calculated, and calibration can be performed based on the calculated estimated measurement value at the center.
JP 2005-208548 A

  As described above, by acquiring and storing the relative ratio LUT in advance, it is possible to acquire the estimated measurement value at the center of the display surface from the measurement value of the swing sensor 30 and perform accurate calibration. However, when the measured value of the central portion of the display surface is estimated by the same method for a color display liquid crystal display device, the following problems occur. FIG. 13 is a schematic diagram for explaining a problem in the case of a color display liquid crystal display device, and shows a graph of the relative ratio LUT. In the case of a color display liquid crystal display device, it is necessary to create a relative ratio LUT for each of three color components of red (R), green (G), and blue (B). However, since the user can change the color balance setting in the liquid crystal display device for color display, even if the optimum relative ratio LUT (see FIG. 13A) is obtained with one setting, for example, the user can When the color balance setting is changed so as to weaken the R component, the optimum relative ratio LUT (see FIG. 13B) is different, so that the measured value at the center of the display surface cannot be estimated with high accuracy.

  In order to solve this problem, it is conceivable that the relative ratio LUT is acquired and stored in advance for all of the assumed color balances, but only the memory capacity for storing the relative ratio LUT is increased. In addition, there is a problem that enormous measurement time is required to obtain a large number of relative ratio LUTs. Alternatively, the relative ratio LUT can be acquired every time the color balance is changed, but this operation has a problem that it is troublesome because the user must perform the operation.

  Further, since the relative ratio LUT needs to be acquired in advance for all gradations that can be displayed by the liquid crystal display device 201, there is a problem that it takes time to acquire the relative ratio LUT. Further, since the gradation and the relative ratio are stored in the relative ratio LUT in association with each other, when the measurement value at the center of the display surface is estimated, when the measurement value is acquired by the swing sensor 30, Since it is necessary to know the gradation that the liquid crystal display device 201 was displaying, the liquid crystal display device 201 and the swing sensor 30 need to perform processing in a coordinated manner. There is also a problem that this method cannot be applied to a liquid crystal display device that is not provided.

  The present invention has been made in view of such circumstances, and an object of the present invention is to store the characteristic amount of the central portion of the display surface of the liquid crystal panel and the characteristic amount of the peripheral portion which are detected in advance in association with each other. In addition, the characteristic amount of the peripheral portion of the display surface is detected, and the characteristic amount of the center portion corresponding to the stored characteristic amount is acquired, or the detected characteristic amount of the peripheral portion Depending on the gradation displayed on the liquid crystal panel, the central characteristic amount is calculated based on the correspondence of the stored characteristic amount. To provide a liquid crystal display device, a characteristic amount measuring device for a liquid crystal display device, a characteristic amount measuring method, and a computer program that can estimate the characteristic amount of the central portion from the characteristic amount of the peripheral portion of the display surface .

  Another object of the present invention is to detect the correspondence between the characteristic amount of the central portion of the display surface and the characteristic amount of the peripheral portion in advance and store a plurality of discretely, and the characteristic amount of the peripheral portion of the display surface. When calculating the characteristic amount of the central portion from the above, it is obtained from the stored characteristic amount that is close to the detected characteristic amount of the peripheral portion, and the characteristic amount of the central portion is calculated by interpolation processing such as linear interpolation Accordingly, an object of the present invention is to provide a liquid crystal display device, a characteristic amount measuring device for a liquid crystal display device, a characteristic amount measuring method, and a computer program that require a small amount of characteristic amounts to be detected and stored beforehand.

  Another object of the present invention is to store the characteristic amount of the central portion and the peripheral portion of the display surface detected in advance as tristimulus values, and use the chromaticities of the three primary colors of red, green and blue. By converting the detected peripheral characteristic amount into tristimulus values and acquiring or calculating the central characteristic amount, the central characteristic amount is interpolated from the detected peripheral characteristic amount, etc. It is an object of the present invention to provide a liquid crystal display device, a characteristic amount measuring device for a liquid crystal display device, a characteristic amount measuring method, and a computer program that can perform calculation with high accuracy.

  Another object of the present invention is to provide a means for detecting the characteristic amount of the central portion of the display surface, detect the characteristic amount of the central portion of the display surface and the characteristic amount of the peripheral portion, and detect the detected characteristic. By adopting a configuration in which the amounts are stored in association with each other, when the characteristics of the liquid crystal panel change due to secular change or the like, the characteristic amounts in the central portion and the peripheral portion of the display surface stored in association with each other can be updated. An object of the present invention is to provide a liquid crystal display device, a characteristic amount measuring device for the liquid crystal display device, a characteristic amount measuring method, and a computer program.

  Another object of the present invention is to obtain a display obtained or calculated based on the characteristic amount of the central portion and the peripheral portion of the display surface stored in advance and the characteristic amount of the peripheral portion of the detected display surface. By adjusting the display characteristics for displaying images on the display surface of the liquid crystal panel according to the characteristic amount at the center of the surface, it is possible to adjust the display characteristics with high accuracy based on the characteristic amount of the display surface. An object of the present invention is to provide a liquid crystal display device, a characteristic amount measuring device for the liquid crystal display device, a characteristic amount measuring method, and a computer program.

A liquid crystal display device according to a first aspect of the present invention includes a liquid crystal panel that displays an image corresponding to a gradation level of image data on a display surface, and a peripheral characteristic amount that detects a luminance or chromaticity characteristic amount of a peripheral portion of the display surface. In a liquid crystal display device including a detection unit, a storage unit that stores in advance a plurality of gradation levels by associating a characteristic amount of a central portion and a characteristic amount of a peripheral portion of the display surface at the same gradation level, and a specification Determining whether or not the characteristic amount detected by the peripheral characteristic amount detection unit is included in the characteristic amount stored in advance by the storage unit when an image corresponding to the gradation level is displayed on the display surface And a characteristic value stored in the storage means in advance in the central portion of the display surface corresponding to the characteristic amount detected by the peripheral characteristic amount detection means when the determination means determines that the information is included. taken to get from the amount And the characteristic detected by the peripheral characteristic amount detection means based on the characteristic amount of the central portion and the characteristic amount of the peripheral portion stored in advance in the storage means when the determination means determines that they are not included. Calculating means for calculating the characteristic amount of the central portion of the display surface with respect to the amount, and if the determining means determines that it is included, the characteristic amount of the central portion acquired by the acquiring means And a means for storing the characteristic amount of the central portion calculated by the calculating means together with a specific gradation level when the determining means determines that the calculated value is not included .

  In the liquid crystal display device according to a second aspect of the present invention, the storage means stores a plurality of discrete characteristic quantities of the central portion and the peripheral portion of the display surface, and the calculation means stores the storage section. A characteristic quantity close to the characteristic quantity detected by the peripheral characteristic quantity detection means is obtained from the characteristic quantity stored in the means, and an interpolation process is performed to calculate the characteristic quantity in the central portion. .

  In the liquid crystal display device according to the third aspect of the invention, the storage means stores characteristic amounts as tristimulus values, and the peripheral characteristic amount detection means sets the chromaticities of the three primary colors red, green and blue. It is detected as a quantity, and is provided with conversion means for converting the chromaticity of each color detected by the peripheral characteristic quantity detection means into tristimulus values.

  According to a fourth aspect of the present invention, there is provided a liquid crystal display device comprising: a central characteristic amount detecting unit that detects a characteristic amount at a central portion of the display surface; a characteristic amount detected by the central characteristic amount detecting unit; and the peripheral characteristic amount detecting unit. Means for associating the detected characteristic quantity with each other and storing it in the storage means.

  The liquid crystal display device according to a fifth aspect of the present invention provides a display when displaying an image on the display surface according to the characteristic amount of the central portion acquired by the acquisition means or the characteristic amount of the central portion calculated by the calculation means. An adjustment means for adjusting the characteristics is provided.

According to a sixth aspect of the present invention, there is provided a characteristic amount measuring apparatus for a liquid crystal display device, which is attached to a liquid crystal display device that displays an image in accordance with a gradation level of video data, and the luminance of the peripheral portion of the display surface of the liquid crystal display device. Alternatively, in a characteristic amount measuring apparatus for a liquid crystal display device provided with a peripheral characteristic amount detecting means for detecting a characteristic amount of chromaticity, the characteristic amount of the central portion of the display surface and the characteristic amount of the peripheral portion at the same gradation level are associated with each other. The storage means stores in advance a plurality of gradation levels, and the storage means stores the characteristic amounts detected by the peripheral characteristic amount detection means when an image corresponding to a specific gradation level is displayed on the display surface. A determination unit that determines whether or not the characteristic amount is stored in advance, and the display surface that corresponds to the characteristic amount detected by the peripheral characteristic amount detection unit when the determination unit determines that the characteristic amount is included. Central part of A characteristic quantity, said obtaining means for obtaining from the pre-stored characteristic quantities in the storage means, when said judging means is not included is determined, the characteristics of pre-stored central in the storage means and the peripheral portion Based on the characteristic amount, the calculation means for calculating the characteristic amount of the central portion of the display surface with respect to the characteristic amount detected by the peripheral characteristic amount detection means, and when the determination means determines that it is included, The characteristic amount of the central part acquired by the acquisition unit is stored together with a specific gradation level, and when the determination unit determines that it is not included, the characteristic amount of the central part calculated by the calculation unit is specified. And means for storing together with the gradation level .

  In the characteristic amount measurement apparatus for a liquid crystal display device according to a seventh aspect of the present invention, the storage means stores a plurality of discrete characteristic amounts in the central portion and peripheral portions of the display surface, and the calculation The means obtains a characteristic quantity close to the characteristic quantity detected by the peripheral characteristic quantity detection means from the characteristic quantity stored in the storage means, and performs interpolation processing to calculate the central characteristic quantity. It is characterized by that.

  In the characteristic amount measuring apparatus for a liquid crystal display device according to an eighth aspect of the present invention, the storage means stores characteristic amounts as tristimulus values, and the peripheral characteristic amount detection means includes the three primary colors of red, green and blue. The chromaticity of each color is detected as a characteristic quantity, and conversion means for converting the chromaticity of each color detected by the peripheral characteristic quantity detection means into tristimulus values is provided.

  According to a ninth aspect of the invention, there is provided a characteristic amount measuring apparatus for a liquid crystal display device, comprising: a central characteristic amount detecting means for detecting a characteristic amount at a central portion of the display surface; a characteristic amount detected by the central characteristic amount detecting means; Means for associating and storing the characteristic quantity detected by the characteristic quantity detection means in the storage means.

  A characteristic amount measuring apparatus for a liquid crystal display device according to a tenth aspect of the present invention is a method for displaying an image on the display surface in accordance with a central characteristic amount acquired by the acquisition unit or a central characteristic amount calculated by the calculation unit. It is characterized by comprising adjusting means for adjusting display characteristics when displaying.

A characteristic amount measuring method according to an eleventh aspect of the invention measures a characteristic amount of luminance or chromaticity of the display surface of a liquid crystal display device including a liquid crystal panel that displays an image corresponding to the gradation level of the image data on the display surface. in the characteristic quantity measuring method of, in association with characteristics of characteristic quantity and the peripheral portion of the central portion of the display surface at the same gray level, previously stored for a plurality of gradation levels, the particular gray level When the video corresponding to the display surface is displayed on the display surface, the characteristic amount of the peripheral portion of the display surface is detected, and the detected characteristic amount of the peripheral portion of the display surface is stored in association with the display surface in advance. It is determined whether it is included in the characteristic amount of the central portion and the characteristic amount of the peripheral portion, and if included, the characteristic amount of the central portion of the display surface corresponding to the detected characteristic amount of the peripheral portion is determined. acquires from the characteristic amount of pre-stored central, The properties of obtained the central store with a specific gray level, if not included, based on the characteristic quantity of characteristic quantity and the peripheral portion of the previously stored central characteristic of the peripheral portion detected The characteristic amount of the central part is calculated with respect to, and the calculated characteristic amount of the central part is stored together with a specific gradation level .

  The characteristic amount measuring method according to the twelfth aspect of the present invention discretely stores the characteristic amount of the central portion and the peripheral portion of the display surface, and detects the characteristic amount of the peripheral portion detected from the stored characteristic amount. A characteristic amount close to is obtained, and interpolation processing is performed to calculate the characteristic amount in the central portion.

  The characteristic amount measuring method according to the thirteenth aspect of the present invention stores characteristic amounts as tristimulus values, detects characteristic amounts in the peripheral portion of the display surface as chromaticities of the three primary colors red, green and blue, and detects them. The chromaticity of each color is converted into tristimulus values.

  The characteristic amount measuring method according to the fourteenth aspect of the invention is characterized in that the characteristic amount at the central portion of the display surface is detected, and the detected characteristic amount at the central portion and the detected characteristic amount at the peripheral portion are stored in association with each other. And

  The characteristic amount measuring method according to the fifteenth aspect of the invention is characterized in that display characteristics when displaying an image on the display surface are adjusted according to the acquired or calculated characteristic amount of the central portion.

According to a sixteenth aspect of the present invention, there is provided a computer program for detecting, on a computer, a liquid crystal panel that displays an image corresponding to a gradation level of image data on a display surface, and a characteristic amount of luminance or chromaticity at a peripheral portion of the display surface. In a computer program for measuring a characteristic amount of the display surface of a liquid crystal display device including a peripheral characteristic amount detecting means, the peripheral characteristic is displayed when an image corresponding to a specific gradation level is displayed on the display surface on the computer. It is determined whether or not the characteristic amount of the peripheral portion detected by the amount detection means is included in the characteristic amount of the central portion of the display surface and the characteristic amount of the peripheral portion stored in association with each other. in this case, in which the characteristics of the central portion of the display surface, the edges characteristic amount detecting means corresponds to the characteristics of the peripheral portion detected, is obtained from the characteristics of pre-stored central, acquired The characteristic quantity of parts are stored with a particular gray level, if not included in advance the characteristics of the stored central and based on the characteristics of the peripheral portion, the central portion on the properties of the peripheral portion detected The characteristic amount is calculated , and the calculated central portion characteristic amount is stored together with a specific gradation level .

  According to a seventeenth aspect of the present invention, there is provided a computer program according to a feature quantity detected by the peripheral characteristic quantity detecting means from a characteristic quantity at a central portion of the display surface and a characteristic quantity at a peripheral portion which are discretely stored in a computer. It is characterized in that a close characteristic amount is acquired and interpolation processing is performed to calculate a central characteristic amount.

  A computer program according to an eighteenth aspect of the invention causes a computer to convert a characteristic quantity of the peripheral portion of the display surface detected by the peripheral characteristic quantity detection unit as chromaticities of the three primary colors of red, green, and blue into a tristimulus value. It is characterized by that.

  According to a nineteenth aspect of the present invention, the computer program according to the nineteenth aspect of the present invention is obtained by detecting the central characteristic amount detected by the central characteristic amount detecting means for detecting the characteristic amount of the central portion of the display surface and the peripheral characteristic amount detecting means. The characteristic amount of the peripheral portion is stored in association with each other.

  The computer program according to the twentieth invention is characterized by causing a computer to adjust display characteristics when displaying an image on the display surface in accordance with the acquired or calculated characteristic value of the central portion.

  In the present invention, characteristic quantities such as luminance or chromaticity at the center and peripheral parts of the display surface of the liquid crystal panel are detected in advance, and the detected characteristic quantities are associated and stored in a memory or a hard disk. When performing calibration, etc., the characteristic amount of only the peripheral portion of the display surface is detected, and the characteristic amount of the central portion of the display surface is estimated based on the pre-stored central portion and the peripheral portion of the characteristic amount. Calibration according to the characteristic amount of the part is performed. In the case where the peripheral characteristic amount measured in the calibration is included in the peripheral characteristic amount stored in advance, the central characteristic amount corresponding to the peripheral characteristic amount may be read and acquired. Is possible. When the measured characteristic amount of the peripheral portion is not included, the calculation is performed by performing arithmetic processing such as interpolation processing based on the central portion and the peripheral portion characteristic amount stored in advance. Rather than storing the relative ratio in association with the gradation that can be displayed on the liquid crystal panel as in the past, it is only necessary to store the characteristic values of the central part and the peripheral part measured in advance. In this case, it is possible to acquire or calculate the characteristic amount of the central portion without depending on the gradation. Therefore, even when the color balance is changed, it is possible to easily acquire or calculate the characteristic amount in the central portion. In addition, since it does not depend on the gradation displayed on the liquid crystal panel, even with a conventional liquid crystal display device that does not have this function, the same calibration can be performed by adding a measuring device having this function. It becomes possible.

  Further, in the present invention, the characteristic amounts of the central portion and the peripheral portion of the display surface are associated with each other and detected and stored in advance. If the characteristic amount of the peripheral part of the display unit detected during calibration or the like is not included in the pre-stored characteristic amount, it is obtained from the stored characteristic amount and is linearly interpolated. The characteristic amount of the central portion is calculated with respect to the characteristic amount of the peripheral portion detected by performing interpolation processing such as the above. When the linearity of the characteristic amount detected in advance is high, the central characteristic amount can be calculated without reducing the calculation accuracy, and the number of characteristic amounts stored in advance can be reduced.

  In the present invention, the characteristic amount of the central portion of the display surface and the characteristic amount of the peripheral portion are stored in advance as tristimulus values. When detecting the characteristic amount of the peripheral portion of the display surface, the characteristic amount is detected as the chromaticity of the three primary colors of red, green, and blue, and the detected chromaticity of each color is converted into a tristimulus value. By storing the characteristic amount as a tristimulus value, a highly linear value can be stored, and the characteristic amount at the center can be calculated easily and accurately by interpolation processing such as linear interpolation. It becomes possible.

  In the present invention, the apparatus is provided with means for detecting the characteristic amount at the center of the display surface. As a result, when the liquid crystal display device is used for a long time and the characteristics of the liquid crystal panel change over time, the characteristic amounts of the central portion and the peripheral portion of the display surface are detected again and stored in association with each other. It becomes possible to update the characteristic amount of the central portion and the peripheral portion of the display surface.

  In the present invention, the characteristic amount of the central portion of the display surface is acquired based on the characteristic amount of the central portion and the peripheral portion of the display surface stored in advance and the characteristic amount of the peripheral portion of the detected display surface. Alternatively, calculation is performed, and display characteristics of the liquid crystal panel are adjusted according to this characteristic amount, so-called calibration. As described above, since the central portion of the characteristic amount can be obtained or calculated with high accuracy from the peripheral portion of the display surface, the calibration can be accurately performed according to the central portion of the characteristic amount.

  In the case of the first invention, the sixth invention, the eleventh invention and the sixteenth invention, the characteristic amount of the central portion of the display surface of the liquid crystal panel and the characteristic amount of the peripheral portion which are detected in advance are stored in association with each other and displayed. Depends on the gradation displayed on the liquid crystal panel by detecting the characteristic amount of the peripheral portion of the surface and acquiring or calculating the characteristic amount of the central portion based on the correspondence of the stored characteristic amount It is possible to estimate the characteristic amount of the central portion from the detected characteristic amount of the peripheral portion without any problem, and easily and accurately estimate the characteristic amount of the central portion of the display surface even when the color balance is changed. Therefore, calibration of a liquid crystal display device for color display can be performed with high accuracy. Further, even in a conventional liquid crystal display device that does not have this function, the same calibration can be performed by adding a measuring device having this function. Therefore, it is easy to automate processing such as calibration of the liquid crystal display device or check of display characteristics, and the display quality of the liquid crystal display device can be maintained at a high level.

  In the second invention, the seventh invention, the twelfth invention, and the seventeenth invention, the correspondence between the characteristic amount of the central portion of the display surface and the characteristic amount of the peripheral portion is detected in advance and stored in a discrete manner. The characteristic value is high in linearity by obtaining from the memorized characteristic value that is close to the detected characteristic value of the peripheral part and calculating the characteristic value of the central part by performing an interpolation process such as linear interpolation. In this case, since the number of characteristic quantities stored in advance can be reduced without reducing the calculation accuracy, the required storage capacity can be reduced and the characteristics of the central part and the peripheral part for pre-storing can be reduced. The amount can be detected in a short time. Therefore, the parts cost and manufacturing cost of the apparatus can be reduced, and an inexpensive apparatus can be provided.

  Further, in the case of the third invention, the eighth invention, the thirteenth invention and the eighteenth invention, the characteristic amount of the central portion and the characteristic amount of the peripheral portion detected in advance are stored as tristimulus values, red, A highly linear value as a characteristic quantity by converting the characteristic quantity of the peripheral part detected by the chromaticity of the three primary colors of green and blue into tristimulus values and acquiring or calculating the characteristic quantity of the central part. Therefore, the characteristic amount of the central portion can be calculated easily and accurately by interpolation processing such as linear interpolation. Therefore, calibration and the like can be performed accurately and at high speed, and the display quality of the liquid crystal display device can be maintained at a high level.

  According to the fourth, ninth, fourteenth and nineteenth inventions, means for detecting the characteristic amount of the central portion of the display surface are provided, and the characteristic amount of the central portion of the display surface and the characteristic of the peripheral portion are provided. By detecting the quantity and storing the detected characteristic quantity in association with each other, the characteristic quantity in the central portion and the peripheral portion of the display surface is detected again, and the center of the display surface stored in advance in association with each other. The characteristic amount of the part and the peripheral part can be updated. Therefore, even when the characteristics of the liquid crystal panel change over time, calibration and the like can be performed with high accuracy by updating the pre-stored characteristic amount, and the display quality of the liquid crystal display device can be enhanced. Can keep.

  Further, in the case of the fifth, tenth, fifteenth and twentieth inventions, the characteristic amounts of the central portion and the peripheral portion of the display surface stored in association with each other and the detected characteristic amounts of the peripheral portion of the display surface Based on the above, the characteristic quantity at the center of the display surface is acquired or calculated, and the display characteristic of the liquid crystal panel is adjusted according to this characteristic quantity. High-accuracy adjustment can be performed based on the acquired characteristic amount of the central portion, and the display quality of the liquid crystal display device can be maintained at a high level.

  Hereinafter, the present invention will be specifically described with reference to the drawings showing embodiments thereof. FIG. 1 is a schematic perspective view showing an appearance of a liquid crystal display device according to the present invention. In the figure, reference numeral 1 denotes a liquid crystal display device for color display. The liquid crystal display device 1 is provided with a display surface 2 by a liquid crystal panel on the front of a substantially rectangular plate-like main body portion so as to display an image, and a stand is provided on the rear surface so that it is on a desk or a floor. The main body portion is supported so that the display surface 2 is substantially vertical.

  Further, a swing sensor 30 for detecting characteristic quantities such as luminance and chromaticity of the peripheral portion of the display surface 2 is detachably attached to the upper side of the main body portion of the liquid crystal display device 1. The swing sensor 30 has a substantially rectangular plate shape, an optical sensor is disposed in the vicinity of one end portion, and a moving portion 31 pivotally supported at the other end portion. The moving part 31 is located between the position where the optical sensor faces the peripheral part of the display surface 2 and the position that is accommodated in the accommodating part 32 provided in the main body portion of the swing sensor 30 and does not face the display surface 2. It moves by the power of the DC motor. It is also possible to automatically detect the characteristic amount of the display surface 2 by moving the moving unit 31 automatically.

  2 and 3 are block diagrams showing the configuration of an apparatus for executing the characteristic amount measuring method according to the present invention. The characteristic amount measurement method according to the present invention includes the liquid crystal display device 1 and the swing sensor 30 described above, the external light sensor 40 for manually detecting the characteristic amount of the central portion of the display surface 2 of the liquid crystal display device 1, and these. This can be done using a PC 50 that controls the three devices.

  The liquid crystal display device 1 includes a liquid crystal panel 3, a backlight 4, a control unit 5, a ROM 6, a RAM 7, an operation unit 8, a signal input unit 9, a backlight drive unit 10, a liquid crystal drive unit 11, and the like. The signal input unit 9 of the liquid crystal display device 1 has a connection terminal connected to an external device such as the PC 50 via a cable, and acquires a video signal input from the external device. The apparatus 1 displays video on the display surface 2 of the liquid crystal panel 3 based on this video signal. The video signal input to the signal input unit 9 may be either an analog signal format or a digital signal format.

  The control unit 5 is connected to each unit in the liquid crystal display device 1 via a bus, and performs various processes such as video display by controlling these operations. The ROM 6 is composed of a nonvolatile memory element such as a mask ROM or EEPROM, for example, and stores various programs and data necessary for the operation of the control unit 5 in advance. The RAM 7 is composed of a rewritable memory element such as SRAM or DRAM. For example, the control unit 5 loads a program stored in the ROM 6 to the RAM 7 and executes the program, and stores temporary data generated along with the execution of the program in the RAM 7.

  The operation unit 8 includes various function keys for operating the liquid crystal display device 1. For example, various setting keys such as a key for setting the brightness (brightness) of the display surface 2 and a key for setting the color balance of an image displayed on the display surface 2 are provided in the operation unit 8. is there. The operation unit 8 receives user operations on these function keys and notifies the control unit 5, and the control unit 5 controls each unit according to the received user operations and updates the settings. It is.

  The liquid crystal panel 3 has a structure in which a pair of glass substrates are opposed to each other, and a liquid crystal layer, which is a liquid crystal substance, is formed in a gap between the glass substrates. One glass substrate is provided with a plurality of pixel electrodes and a TFT (Thin Film Transistor) having a drain connected to each of the pixel electrodes, and the other glass substrate is provided with a common electrode. The gate and source of the TFT are connected to the output stages of the gate driver 11a and the source driver 11b of the liquid crystal driving unit 11, respectively.

  The liquid crystal drive unit 11 is controlled by the control unit 5 to drive the liquid crystal panel 3 based on the video signal input to the signal input unit 9. The gate driver 11a of the liquid crystal driving unit 11 is configured to selectively apply a voltage to the gates of a large number of TFTs of the liquid crystal panel 3 in accordance with the input video signal. Similarly, the source driver 11b A voltage is applied to the source at a voltage value corresponding to the input video signal.

  In the liquid crystal panel 3, on / off of the TFT of each pixel is controlled by the voltage applied from the gate driver 11a, and the output voltage (input level to the liquid crystal panel 3) input from the source driver 11b is set to each pixel during the on period. By applying the light to the TFT, the light transmittance determined by the electro-optical characteristics of the liquid crystal substance is controlled, the light transmission from the light source is adjusted, and the image is displayed in gradation. The liquid crystal panel 3 is sandwiched between a pair of polarizing plates (not shown), and a backlight 4 serving as a light source is disposed on the back side thereof. Further, the front side of the liquid crystal panel 3 is exposed to the outside, and the front side forms a display surface 2 on which an image is displayed.

  The backlight 4 is driven by an output voltage supplied from the backlight drive unit 10, and the backlight drive unit 10 is controlled by the control unit 5 and output according to the brightness set by the user operating the operation unit 8. The voltage is adjusted and applied to the backlight 4 to adjust the luminance of the backlight 4. Thereby, the brightness on the display surface 2 of the liquid crystal panel 3 can be adjusted.

  The swing sensor 30 attached to the liquid crystal display device 1 includes an optical sensor 33, a DC motor 34, a motor drive unit 35, an I / F (interface) unit 36, and the like. The optical sensor 33 provided in the moving unit 31 includes a light receiving element such as a phototransistor, an A / D conversion circuit, and the like, and characteristics such as luminance or chromaticity in the peripheral portion of the display surface 2 of the liquid crystal panel 3. The voltage output from the light receiving element according to the quantity is converted into a digital electric signal by the A / D conversion circuit and output.

  The DC motor 34 generates power for rotating the moving unit 31 along the display surface 2 of the liquid crystal display 3, and is driven by a voltage supplied from the motor driving unit 35. The motor drive unit 35 generates a desired voltage and applies it to the DC motor 34 to control the rotation direction and the rotation amount of the DC motor 34, thereby detecting the position where the characteristic amount of the display surface 2 is detected by the optical sensor 33 or not. The moving unit 31 is moved to one of the detection positions.

  Further, the optical sensor 33 and the motor drive unit 35 are connected to the I / F unit 36, respectively. The I / F unit 36 is connected to the PC 50 via a cable, gives the characteristic amount of the display surface 2 detected by the optical sensor 33 to the PC 50 as digital data, and obtains a control command from the PC 50 to drive the motor. This is given to the part 35. As a result, the motor drive unit 35 drives the DC motor 34 and moves the moving unit 31 to detect the characteristic amount by the optical sensor 33.

  The external light sensor 40 detects a characteristic amount such as luminance or chromaticity of the display surface 2 in the same manner as the light sensor 33 of the swing sensor 30. However, the liquid crystal display device 1 is not always attached to the liquid crystal display device 1 as in the case of the swing sensor 30, but is used by being fixed to the approximate center of the display surface 2 with a double-sided tape or the like only when detection is performed. In addition, it is additionally used when acquiring the correlation between the characteristic amount of the central portion of the display surface 2 and the characteristic amount of the peripheral portion at the time of manufacturing, attaching the swing sensor 30 or periodically. The external light sensor 40 is connected to the PC 50 only during use, and the characteristic amount detected by the external light sensor 40 is given to the PC 50 as digital data.

  The PC 50 includes a CPU 51, a RAM 52, an operation unit 53, I / F units 54 and 55, a signal output unit 56, a storage unit 60, and the like. The CPU 51 is connected to other hardware units via a bus, performs processing for controlling the operations of these units, and executes processing such as computation by executing various programs stored in the storage unit 60. To do. The RAM 52 is configured by a memory element such as SRAM or DRAM, and temporarily stores various programs and data when the CPU 51 performs processing.

  The operation unit 53 receives a user operation performed on a device such as a mouse and a keyboard, and performs a process of notifying the CPU 51 of the operation content. The I / F units 54 and 55 are provided with connection terminals conforming to a standard such as USB or RS232C, for example, for transmitting / receiving data to / from an external device. In the example shown in FIG. The external light sensor 40 is connected as necessary and always connected. The signal output unit 56 is connected to the liquid crystal display device 1, outputs a display video signal generated by the processing of the CPU 51 to the liquid crystal display device 1, and outputs a desired video on the display surface 2 of the liquid crystal display device 1. It can be displayed.

  The storage unit 60 is composed of a large-capacity storage device such as a hard disk, and although not shown, various programs such as an operating system, application programs, and control programs, and data used by these programs Alternatively, data generated by these programs is stored. In the present embodiment, the storage unit 60 stores a calibration program 61, an ideal gradation characteristic table 62, an LUT 63, a correlation table 64, and the like.

  The ideal gradation table 62 is a gradation level related to video data displayed on the liquid crystal display device 1 and an ideal luminance or color when the liquid crystal panel 3 of the liquid crystal display device 1 displays the gradation level. It is a table in which characteristic quantities such as degrees are stored in association with each other. The LUT 63 is a table in which input levels to be given to the liquid crystal panel 3 in association with each gradation level are stored in association with each other so that the ideal characteristic amount stored in the ideal gradation table 62 is obtained. The CPU 51 converts the gradation level of each pixel of the video data generated by the execution of various programs into an optimum input level to the liquid crystal panel 3 based on the LUT 63, and the liquid crystal display from the signal output unit 56 as a video signal. The data is output to the device 1.

  However, when the liquid crystal display device 1 undergoes a secular change due to continuous use of the liquid crystal display device 1 and a slight change occurs in the display characteristics of the liquid crystal panel 3, conversion from the gradation level to the input level by the LUT 63 stored in advance. In some cases, an image cannot be displayed with the ideal characteristic amount stored in the ideal gradation table 62. For this reason, a calibration program 61 that performs a process of updating the LUT 63 according to the changed display characteristics of the liquid crystal panel 3 (hereinafter referred to as calibration process) is stored in the storage unit 60, and the CPU 51 stores the calibration program 61. By executing and updating the LUT 63, the liquid crystal panel 3 can display an image with an ideal characteristic amount. The calibration process may be performed by the user operating the operation unit 53 to cause the PC 50 to execute the calibration program 61, or may be automatically performed at a predetermined cycle. If it has a function of connecting to a network, it may be performed by remote control using a server computer or the like.

  In the calibration process by the calibration program 61, the characteristic amount of the display surface 2 of the liquid crystal display device 1 is detected using the swing sensor 30, and the difference from the ideal characteristic amount stored in the ideal gradation table 62 is canceled out. As described above, the input level stored in the LUT 63 is updated. However, the swing sensor 30 is configured to detect the characteristic amount of the peripheral portion of the display surface 2, but the calibration process is preferably performed based on the characteristic amount of the central portion of the display surface 2. Therefore, the storage unit 60 stores a correlation table 64 in which the characteristic amount of the central portion of the display surface 2 and the characteristic amount of the peripheral portion are stored in association with each other, and the calibration program 61 stores the correlation table 64. Based on the characteristic amount of the peripheral portion of the display surface 2 detected by the swing sensor 30, the central characteristic amount is acquired or calculated, and the calibration process is performed based on the central characteristic amount.

  FIG. 4 is a schematic diagram illustrating an example of the correlation table 64. The correlation table 64 is a table in which the characteristic amount of the peripheral portion of the display surface 2 detected by the swing sensor 30 and the characteristic amount of the central portion of the display surface 2 detected by the external light sensor 40 are stored in association with each other. When the liquid crystal display device 1, the swing sensor 30, and the external light sensor 40 are manufactured and sold as a set, the correlation table 64 is obtained by measuring in advance in the manufacturing process using the swing sensor 30 and the external light sensor 40. When the liquid crystal display device 1 and the swing sensor 30 and the external light sensor 40 are individually manufactured and sold, the correlation table 64 may be created by performing measurement when the swing sensor 30 is attached. . When the correlation table 64 is created in the manufacturing process, the created correlation table 64 may be provided by being recorded on a recording medium such as a CD-ROM, or stored in the storage unit 60 of the PC 50 and provided together with the PC 50. May be. Further, the user can update the correlation table 64 using the swing sensor 30 and the external light sensor 40. The update of the correlation table 64 is provided as a function of the calibration program 61.

  In the correlation table 64, the characteristic amount of the central portion of the display surface 2 and the characteristic amount of the peripheral portion are stored as tristimulus values (X, Y, Z values). In the correlation table 64 shown in FIG. 4, the tristimulus values of the characteristic amount detected by the swing sensor 30 are XSn, YSn, ZSn (n = 0 to 8), and the tristimulus values of the characteristic amount detected by the external light sensor 40 are displayed. Is described as XRn, YRn, ZRn (n = 0-8). When the liquid crystal panel 3 displays 256 gradations, the correlation table 64 stores the results of discrete detection in about nine steps as shown in the figure, and stores them for each measurement gradation level. Furthermore, for each X, Y, and Z value, the ratio of the detection value of the swing sensor 30 to the detection value of the external light sensor 40 (XRn / XSn, YRn / YSn), to the detection value (XSn, YSn, ZSn) of the swing sensor 30 ZRn / ZSn) are stored in association with each other. Note that the correlation table 64 actually stored in the storage unit 60 may not include the item of the measured gradation level shown in FIG. Further, the ratio (XRn / XSn, YRn / YSn, ZRn / ZSn) of the detected value of the swing sensor 30 to the detected value of the external light sensor 40 is stored in association with the detected value (XSn, YSn, ZSn) of the swing sensor 30. However, the present invention is not limited to this, and the detection value (XRn, YRn, ZRn) of the external light sensor 40 is simply associated with the detection value (XSn, YSn, ZSn) of the swing sensor 30 and stored. Also good.

  When the calibration process is performed by the calibration program 61, the swing sensor 30 detects the characteristic amount around the display surface 2 and converts the detected characteristic amount into tristimulus values (XSn, YSn, ZSn). By referring to the correlation table 64, the tristimulus values (XRn, YRn, ZRn) of the characteristic amount at the center can be acquired. At this time, when the tristimulus value related to the characteristic amount detected by the swing sensor 30 is not included in the correlation table 64, and the tristimulus value of the central characteristic amount cannot be directly acquired. Then, linear interpolation processing is performed based on the values stored in the correlation table 64 to obtain the tristimulus values of the characteristic amount at the center.

  FIG. 5 is a schematic diagram showing the correlation table 64 as a graph. The X value of the correlation table 64 shown in FIG. 4 is graphed. Further, (a) shows an overall view of the correlation table 64, and (b) shows a partially enlarged view. Each value of the correlation table 64 that stores the detected characteristic quantities as tristimulus values has high linearity as shown in FIG. 5A and can be approximated by a linear function. For example, when the X value of the characteristic amount detected by the swing sensor 30 during the calibration process is a value XS between XS3 and XS4, (XS3, XR3 / XS3) and (XS4, XR4 / XS4) XR / XR corresponding to XS can be calculated by calculating a straight line connecting the two points (see the broken line in FIG. 5B).

  Thus, by storing the characteristic quantities as tristimulus values in the correlation table 64, the characteristic quantity at the center of the display surface 2 can be calculated with high accuracy by performing linear interpolation processing. For this reason, the correlation table 64 does not need to store values for all 256 gradation levels, but may detect and store about 9 gradation levels in advance as shown in the figure. .

  For example, when the swing sensor 30 detects the characteristic amount with the chromaticities (R, G, and B values) of the three primary colors of red, green, and blue, X is a tristimulus value from the detected R, G, and B values. , Y, Z values need to be converted. Below, the conversion method from R, G, B value to X, Y, Z value is demonstrated easily. When converting from R, G, B values to X, Y, Z values, first convert R, G, B values to Y, x, y values using the following formulas (2) and (3) To do.

  A00 to A33 are constants for conversion, and the following values can be used as an example.

  Next, the calculated Y, x, and y values are converted into X, Y, and Z values. This conversion can be performed using the following equation (4).

  The R, G, and B values detected by the swing sensor 30 during the calibration process are converted into X, Y, and Z values using the equations (2) to (4), and displayed by referring to the correlation table 64. The characteristic amount at the center of the surface 2 can be acquired or calculated as X, Y, and Z values. Although the conversion formula is omitted, the acquired characteristic value of the central portion can be converted from the X, Y, and Z values to the R, G, and B values as necessary by performing the reverse calculation. . When the external light sensor 40 is configured to detect the characteristic amount at the center of the display surface as Y, x, and y values, the detected values are converted into X, Y, and Z values according to the equation (4).

  6 and 7 are flowcharts showing a procedure of processing for creating or updating the correlation table 64. The process of creating or updating the correlation table 64 can be executed as one function of the calibration program 61. When an instruction to execute this process is given by operating the operation unit 53 of the PC 50, first, the liquid crystal A message requesting attachment of the external light sensor 40 is displayed at the center of the display surface 2 of the display device 1 (step S1). At this time, it is preferable to display a graphic or symbol indicating the mounting position of the external light sensor 40 in the center of the display surface 2 together with the message. Thereafter, the external light sensor 40 is attached to the center of the display surface 2 and, for example, it is checked whether or not the external light sensor 40 has been attached by checking whether or not an operation for notifying the completion of the attachment has been performed (step) S2) If the attachment is not completed (S2: NO), the process returns to step S1 to continue displaying the message, and waits until the attachment is completed.

  When the attachment of the external light sensor 40 is completed at the center of the display surface 2 (S2: YES), white is displayed on the entire display surface 2 (step S3), the swing sensor 30 is activated (step S4), and the light The moving unit 31 is moved so that the sensor 33 faces the peripheral part of the display surface 2. Next, the backlight 4 of the liquid crystal display device 1 is turned off, detection is performed by the swing sensor 30 and the external light sensor 40, and zero adjustment is performed using the detection value at this time as a reference value (step S5).

  Next, the backlight 4 is turned on, and the brightness setting is adjusted to a predetermined setting (for example, a brightness of + 5% with respect to the brightness setting when performing the calibration process, or the maximum brightness) (step S6). ), The detection value by the swing sensor 30 at this time is acquired (step S7), and the detection value by the external light sensor 40 is acquired (step S8). The detection values of the swing sensor 30 are R, G, and B values, but the detection values of the external light sensor 40 are Y, x, and y values, and therefore the detection values of the external light sensor 40 are based on the Y, x, and y values. Conversion into R, G, and B values (step S9), and correction coefficients (a, b, c) for correcting the detection value of the swing sensor 30 are calculated based on the following equation (5) (step S10). .

  In equation (5), R0, G0, and B0 are detection values of the swing sensor 30 in step S7, and R ′, G ′, and B ′ are detection values of the external light sensor 40 in step S8. It is the value converted by. In the subsequent processing, values R, G, and B obtained by multiplying the detection values R0, G0, and B0 detected by the swing sensor 30 with correction coefficients a, b, and c, respectively, are used as detection results of the swing sensor 30 (described above). (See equation (6)). In many cases, an inexpensive light receiving element is used for a simple optical sensor such as the swing sensor 30, and in this case, the color ratios of the detection values R0, G0, and B0 tend to vary. By using the correction coefficient, the color ratios of the detection values R0, G0, and B0 are matched to the color ratios of the detection values R ′, G ′, and B ′ of the external light sensor 40 with higher accuracy, and the solid variation of the swing sensor 30 is detected. Can be eliminated. It should be noted that this correction coefficient is not necessary when a light receiving element with little solid variation is used for the swing sensor 30. The calculated correction coefficient is stored in the storage unit 60 (step S11), and the process proceeds to the next process.

  Next, the display on the display surface 2 is changed from white display to gray display (step S21), and the gradation level displayed on the display surface 2 is set to one of the predetermined measurement gradation levels (step S22). For example, in the case of the correlation table 64 shown in FIG. 4, it is necessary to change the measurement gradation level in nine steps, and one of the nine measurement gradation levels is measured in step S22. Set so that

  Next, the swing sensor 30 detects the characteristic amount of the peripheral portion of the display surface 2 to acquire a detection value (step S23), and detects based on the correction coefficient stored in the storage unit 60 and the above equation (6). The values are corrected (step S24), and the corrected detection values of the R, G, and B values are converted into tristimulus values of X, Y, and Z values based on equations (2) to (4) (step S25). Further, the external light sensor 40 detects the characteristic amount of the central portion of the display surface 2 to acquire the detection value (step S26), and the acquired detection values of the Y, x, and y values are based on the equation (4). And converted into tristimulus values of X, Y, and Z values (step S27).

  Next, the ratio XRn / XSn, YRn / YSn, ZRn / ZSn of the detected values XSn, YSn, ZSn of the swing sensor 30 with respect to the detected values XRn, YRn, ZRn of the external light sensor 40, that is, the correlation coefficient is calculated (step) S28), and stored as a correlation table 64 in the storage unit 60 (step S29). It is checked whether or not the storage of the correlation coefficient has been completed for all the measured gradation levels (step S30). If not completed (S30: NO), the process returns to step S22 to return to the unprocessed measured gradation levels. Steps S22 to S29 are repeatedly performed. When processing is completed for all the measured gradation levels (S30: YES), processing for housing the moving unit 31 of the swing sensor 30 in the housing unit 32, processing for restoring the display of the liquid crystal panel 3, and brightness setting A termination process including a process of returning and a process of displaying a message prompting the removal of the external light sensor 40 is performed (step S31), and the process is terminated.

  The correlation table 64 can be created or updated by the above-described procedure. By using the correlation table 64 when performing the calibration process, the characteristic value of the periphery of the display surface 2 detected by the swing sensor 30 can be used to determine the central portion. A characteristic quantity can be acquired. 8 and 9 are flowcharts showing the procedure of the calibration process. In the calibration process, first, it is checked whether or not the correlation table 64 has been stored in the storage unit 60 (step S41). If the correlation table 64 is not stored in the storage unit 60 (S41: NO) Then, an error message is displayed on the display surface 2 of the liquid crystal display device 1 (step S42), and the process ends. At this time, it is preferable to display a message prompting the creation of the correlation table 64.

  When the correlation table 64 is stored in the storage unit 60 (S41: YES), white is displayed on the entire display surface 2 (step S43), the swing sensor 30 is activated (step S44), and the optical sensor 33 is activated. The moving unit 31 is moved so as to face the periphery of the display surface 2. Next, the backlight 4 of the liquid crystal display device 1 is turned off, detection by the swing sensor 30 is performed, and zero adjustment is performed using the detection value at this time as a reference value (step S45). Thereafter, the backlight 4 is turned on, the brightness setting is adjusted to a predetermined setting (step S46), the display on the display surface 2 is changed to gray display (step S47), and the gradation level to be displayed is set to 0. (Step S48).

  Next, the swing sensor 30 detects the characteristic amount of the peripheral portion of the display surface 2 to obtain a detection value (step S49), and the correction coefficients a, b, c stored in the storage unit 60 and the above-described ( 6) The detection value is corrected based on the equation (step S50), and the corrected detection values of the R, G, and B values are converted into tristimulus values of X, Y, and Z values based on the equations (2) to (4). Conversion is performed (step S51).

  Next, it is checked whether or not the tristimulus values obtained in step S51 are included in the values stored in the correlation table 64 in the storage unit 60 (step S52). : YES), the characteristic value of the corresponding central part is acquired from the correlation table 64 (step S53). If not included (S52: NO), linear interpolation processing is performed (step S53), and the central part is obtained. The characteristic amount of is calculated.

  Since the characteristic amount acquired in step S53 or the characteristic amount in the central portion calculated by the interpolation process in step S54 is a tristimulus value of X, Y, and Z values, this is converted into a characteristic amount of R, G, and B values. The central characteristic amount converted into R, G, and B values after conversion (step S55) is stored in the storage unit 60 in association with the gradation level (step S56). Thereafter, it is checked whether or not the measurement of the characteristic amount in the central portion of the display surface 2 has been completed for all the gradation levels that can be displayed on the liquid crystal panel 3 (step S57). (S57: NO), the gradation level is changed by one step (step S58), the process returns to step S49, and the processes of steps S49 to S56 are repeated for all the gradation levels.

  When the measurement of the characteristic amount in the central portion of the display surface 2 is completed for all the gradation levels (S57: YES), the ideal gradation characteristic table 62 stored in the storage unit 60 is read (step S59), and step S56. The LUT 63 is updated based on the characteristic amount of the central portion of the display surface 2 and the gradation characteristics of the ideal gradation characteristic table 62 for all gradation levels stored in the storage unit 60 (step S60).

  FIG. 10 is a flowchart showing the procedure of the update process of the LUT 63, and is the process performed in step S60 of the flowcharts shown in FIGS. The ideal gradation characteristic table 62 stores an ideal characteristic amount associated with the gradation level, and the ideal characteristic amount for the gradation level k in the ideal gradation characteristic table 62 is XTk. (K = 0-255). Further, for the characteristic amount at the center of the display surface 2 stored in step S56, the characteristic amount measured with respect to the gradation level j is set to XTj (j = 0 to 255).

  In the update process of the LUT 63, first, differences (XTk−XTj) between the ideal characteristic amount XTk and the measured characteristic amount XTj are calculated for all combinations (step S71), and the absolute value | XTk−XTj | The combination of the gradation levels k and j that minimizes is extracted (step S72). From the extraction result, the gradation level k is input to the table, the corresponding gradation level j is stored as the table output in the LUT 63 (step S73), and the update process is terminated.

  After the update process of the LUT 63 is completed in step S60, a process of storing the moving unit 31 of the swing sensor 30 in the storage unit 32, a process of restoring the display of the liquid crystal panel 3, a process of returning the brightness setting, and the like. Completion processing is performed (step S61), and the calibration processing is terminated.

  In the characteristic amount measuring method using the liquid crystal display device 1, the swing sensor 30 and the PC 50 having the above configuration, the characteristic amount of the peripheral portion of the display surface 2 by the swing sensor 30 and the external amount are stored as the correlation table 64 in the storage unit 60 of the PC 50. The characteristic amount of the central portion of the display surface 2 by the optical sensor 40 is stored in association with each other, and when performing processing such as calibration, the swing sensor 30 detects the characteristic amount of the peripheral portion of the display surface 2. Then, by acquiring or calculating the characteristic amount of the central portion of the display surface 2 from the correlation table 64, it is possible to perform processing such as accurate calibration from the detection value of the swing sensor 30. Can be easily realized. Further, since the input to the correlation table 64 is a characteristic amount, and the output is also a characteristic amount and does not depend on the gradation level of the liquid crystal panel 3, the same correlation is obtained even when the color balance is changed. Processing can be performed using the table 64, and the characteristic amount can be measured without depending on the type or function of the liquid crystal display device by simply installing the swing sensor 30 and introducing the program into the PC 50. Can do.

  In addition, since the correlation table 64 stores characteristic quantities as tristimulus values, data with high linearity can be stored, so that linear interpolation processing can be performed easily and accurately. Therefore, even in the liquid crystal panel 3 that displays 256 gradations, it is only necessary to discretely store characteristic quantities of about 9 gradations in the correlation table 64, so that the storage capacity can be reduced. At the same time, the time required to create the correlation table 64 can be shortened. Further, when the characteristics of the liquid crystal panel 3 or the backlight 4 change due to secular change or the like and the display characteristics on the display surface 2 change, the correlation table 64 can be updated using the external light sensor 40. Therefore, the display quality of the liquid crystal display device 1 can be maintained at a high level.

  In the present embodiment, the acquisition and calculation of the characteristic amount of the central portion of the display surface 2 is performed for the calibration process. However, the present invention is not limited to this, and the display characteristic of the liquid crystal display device 1 is not limited thereto. It is good also as a structure performed for other purposes, such as check. The correlation table 64 is updated by the calibration program 61. However, the present invention is not limited to this, and another dedicated program may be updated by the correlation table 64. Further, the swing sensor 30 is different from the liquid crystal display device 1 and the swing sensor 30 is attached to the liquid crystal display device 1 for detection. However, the present invention is not limited to this, and the swing sensor 30 is not limited to the liquid crystal display device. It is good also as a structure incorporated in 1. FIG. In addition, the PC 50 performs the calibration process and the correlation table 64 update process. However, the present invention is not limited to this, and the liquid crystal display device 1 may be configured to perform these processes. It is good also as a structure which performs a process. In addition, although the PC 50 outputs the video signal related to the video displayed on the liquid crystal display device 1, the present invention is not limited to this, and other devices may be configured to output.

(Modification)
FIG. 11 is a block diagram showing a configuration of a liquid crystal display device 101 according to a modification of the present embodiment. The liquid crystal display device 101 according to the modified example includes an I / F unit 54 that connects the swing sensor 30 and an I / F unit 55 that connects the external light sensor 40 in addition to the components of the liquid crystal display device 1 shown in FIG. A storage unit 60 in which a calibration program 61, an ideal gradation characteristic table 62, an LUT 63, a correlation table 64, and the like are stored, and a control unit 105 capable of controlling them.

  Therefore, the liquid crystal display device 101 performs processing for displaying the image by converting the gradation level of the video signal supplied from the PC 150 into a gradation level suitable for the liquid crystal panel 3 by the LUT 63, and also performs the calibration processing and correlation described above. An update process or the like of the table 64 can be performed. As described above, the PC 150 may perform the calibration process and the update process of the correlation table 64, but the liquid crystal display device 101 may perform the process itself.

It is a typical perspective view which shows the external appearance of the liquid crystal display device which concerns on this invention. It is a block diagram which shows the structure of the apparatus for performing the characteristic-value measuring method which concerns on this invention. It is a block diagram which shows the structure of the apparatus for performing the characteristic-value measuring method which concerns on this invention. It is a schematic diagram which shows an example of a correlation table. It is the schematic diagram which showed the correlation table as a graph. It is a flowchart which shows the procedure of the process which produces or updates a correlation table. It is a flowchart which shows the procedure of the process which produces or updates a correlation table. It is a flowchart which shows the procedure of a calibration process. It is a flowchart which shows the procedure of a calibration process. It is a flowchart which shows the procedure of the update process of LUT. It is a block diagram which shows the structure of the liquid crystal display device which concerns on the modification of this Embodiment. It is a schematic diagram for demonstrating one method of estimating the characteristic quantity of a center part from the characteristic quantity of the peripheral part of the display surface of a liquid crystal panel. It is a schematic diagram for demonstrating the problem in the case of the liquid crystal display device of a color display.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Liquid crystal display device 2 Display surface 3 Liquid crystal panel 4 Backlight 5 Control part 9 Signal input part 10 Backlight drive part 11 Liquid crystal drive part 30 Swing sensor (characteristic amount measuring apparatus)
31 Moving part 33 Optical sensor (peripheral characteristic amount detection means)
40 External light sensor (central characteristic amount detection means)
50 PC (characteristic measuring device)
51 CPU (determination means, acquisition means, calculation means, conversion means, adjustment means)
56 Signal Output Unit 60 Storage Unit (Storage Unit)
61 Calibration program 62 Ideal gradation characteristics table 63 LUT
64 Correlation table 101 Liquid crystal display device 105 Control unit 150 PC

Claims (20)

In a liquid crystal display device comprising: a liquid crystal panel that displays an image according to a gradation level of video data on a display surface; and a peripheral characteristic amount detection unit that detects a luminance or chromaticity characteristic amount of a peripheral portion of the display surface.
Storage means for previously storing a plurality of gradation levels by associating the characteristic amount of the central portion and the characteristic amount of the peripheral portion of the display surface at the same gradation level ;
It is determined whether or not the characteristic amount detected by the peripheral characteristic amount detection unit when the video corresponding to a specific gradation level is displayed on the display surface is included in the characteristic amount stored in advance by the storage unit. A determination means;
When the determination unit determines that the content is included , the characteristic amount at the center of the display surface corresponding to the characteristic amount detected by the peripheral characteristic amount detection unit is acquired from the characteristic amount stored in advance in the storage unit Acquisition means to
When the determination unit determines that the information is not included, the characteristic amount detected by the peripheral characteristic amount detection unit based on the central characteristic amount and the peripheral characteristic amount stored in advance in the storage unit. Calculating means for calculating the characteristic amount of the central portion of the display surface ;
When the determination means determines that it is included, the characteristic amount of the central portion acquired by the acquisition means is stored together with a specific gradation level, and when the determination means determines that it is not included And a means for storing the characteristic value of the central portion calculated by the calculating means together with a specific gradation level . In the storage means, a plurality of characteristic amounts in the central portion and peripheral portions of the display surface are discretely stored,
The calculating unit obtains a characteristic amount close to the characteristic amount detected by the peripheral characteristic amount detecting unit from the characteristic amount stored in the storage unit, and performs an interpolation process to calculate the central characteristic amount. The liquid crystal display device according to claim 1, wherein the liquid crystal display device is a liquid crystal display device. The storage means stores characteristic quantities as tristimulus values,
The peripheral characteristic amount detecting means detects chromaticities of the three primary colors of red, green and blue as characteristic amounts,
The liquid crystal display device according to claim 1, further comprising conversion means for converting chromaticity of each color detected by the peripheral characteristic amount detection means into tristimulus values. A central characteristic amount detecting means for detecting a characteristic amount at a central portion of the display surface;
4. The apparatus according to claim 1, further comprising: a storage unit that stores the characteristic amount detected by the central characteristic amount detection unit and the characteristic amount detected by the peripheral characteristic amount detection unit in association with each other. The liquid crystal display device according to any one of the above. Adjusting means for adjusting display characteristics when an image is displayed on the display surface according to the characteristic amount of the central portion acquired by the acquisition means or the characteristic amount of the central portion calculated by the calculation means. The liquid crystal display device according to any one of claims 1 to 4. A liquid crystal provided with a peripheral characteristic amount detection unit that is attached to a liquid crystal display device that displays an image corresponding to the gradation level of the video data and detects a luminance or chromaticity characteristic amount of the peripheral portion of the display surface of the liquid crystal display device In the characteristic amount measuring device of the display device,
Storage means for previously storing a plurality of gradation levels by associating the characteristic amount of the central portion and the characteristic amount of the peripheral portion of the display surface at the same gradation level ;
It is determined whether or not the characteristic amount detected by the peripheral characteristic amount detection unit when the video corresponding to a specific gradation level is displayed on the display surface is included in the characteristic amount stored in advance by the storage unit. A determination means;
When the determination unit determines that the content is included , the characteristic amount at the center of the display surface corresponding to the characteristic amount detected by the peripheral characteristic amount detection unit is acquired from the characteristic amount stored in advance in the storage unit Acquisition means to
When the determination unit determines that the information is not included, the characteristic amount detected by the peripheral characteristic amount detection unit based on the central characteristic amount and the peripheral characteristic amount stored in advance in the storage unit. Calculating means for calculating the characteristic amount of the central portion of the display surface ;
When the determination means determines that it is included, the characteristic amount of the central portion acquired by the acquisition means is stored together with a specific gradation level, and when the determination means determines that it is not included A characteristic amount measuring apparatus for a liquid crystal display device , comprising: a means for storing the characteristic value of the central portion calculated by the calculating means together with a specific gradation level . In the storage means, a plurality of characteristic amounts in the central portion and peripheral portions of the display surface are discretely stored,
The calculating unit obtains a characteristic amount close to the characteristic amount detected by the peripheral characteristic amount detecting unit from the characteristic amount stored in the storage unit, and performs an interpolation process to calculate the central characteristic amount. The liquid crystal display device characteristic amount measuring apparatus according to claim 6, wherein the liquid crystal display device has a characteristic amount. The storage means stores characteristic quantities as tristimulus values,
The peripheral characteristic amount detecting means detects chromaticities of the three primary colors of red, green and blue as characteristic amounts,
The liquid crystal display characteristic quantity measuring device according to claim 6 or 7, further comprising conversion means for converting the chromaticity of each color detected by the peripheral characteristic quantity detection means into tristimulus values. A central characteristic amount detecting means for detecting a characteristic amount at a central portion of the display surface;
9. The apparatus according to claim 6, further comprising: a storage unit that stores the characteristic amount detected by the central characteristic amount detection unit and the characteristic amount detected by the peripheral characteristic amount detection unit in association with each other. The characteristic-value measuring apparatus of the liquid crystal display device as described in any one. Adjusting means for adjusting display characteristics when an image is displayed on the display surface according to the characteristic amount of the central portion acquired by the acquisition means or the characteristic amount of the central portion calculated by the calculation means. The apparatus for measuring a characteristic amount of a liquid crystal display device according to any one of claims 6 to 9. In a characteristic amount measuring method for measuring a characteristic amount of luminance or chromaticity of the display surface of a liquid crystal display device including a liquid crystal panel that displays an image corresponding to a gradation level of video data on the display surface,
Associating the characteristic amount of the central portion of the display surface and the characteristic amount of the peripheral portion at the same gradation level, storing in advance for a plurality of gradation levels ,
When a video corresponding to a specific gradation level is displayed on the display surface, the characteristic amount of the peripheral portion of the display surface is detected,
It is determined whether or not the detected characteristic amount of the peripheral portion of the display surface is included in the characteristic amount of the central portion of the display surface and the characteristic amount of the peripheral portion stored in association with each other,
If it does, the characteristics of the central portion of the display surface corresponding to the characteristic amount of the peripheral portion detected, is obtained from the characteristics of pre-stored central, the characteristics of the obtained central Memorize it with a specific gradation level,
If it is not included, the central characteristic value is calculated with respect to the detected peripheral characteristic value based on the central characteristic value and peripheral characteristic value stored in advance, and the calculated central characteristic value is calculated. Is stored together with a specific gradation level . The characteristic amount of the central portion of the display surface and the characteristic amount of the peripheral portion are stored discretely,
The characteristic amount measurement method according to claim 11, wherein a characteristic amount close to the detected peripheral portion characteristic amount is acquired from the stored characteristic amount, and the central portion characteristic amount is calculated by performing an interpolation process. The characteristic amount is stored as a tristimulus value,
Detecting the characteristic amount of the peripheral portion of the display surface as the chromaticity of the three primary colors of red, green and blue;
The characteristic amount measuring method according to claim 11 or 12, wherein the detected chromaticity of each color is converted into a tristimulus value. Detecting a characteristic amount at the center of the display surface,
The characteristic amount measuring method according to any one of claims 11 to 13, wherein the detected characteristic amount of the central portion and the detected characteristic amount of the peripheral portion are stored in association with each other. The characteristic amount according to any one of claims 11 to 14, wherein a display characteristic when an image is displayed on the display surface is adjusted according to the acquired characteristic amount of the central portion. Measuring method. A liquid crystal display comprising a liquid crystal panel for displaying on the display surface an image corresponding to the gradation level of the image data on a computer, and a peripheral characteristic amount detecting means for detecting a luminance or chromaticity characteristic amount of the peripheral portion of the display surface In a computer program for measuring a characteristic amount of the display surface of an apparatus,
On the computer,
The characteristic amount of the central portion of the display surface in which the peripheral characteristic amount detected by the peripheral characteristic amount detection unit is stored in association with each other when the video corresponding to the specific gradation level is displayed on the display surface. And whether it is included in the characteristic amount of the peripheral part,
If it does, the characteristics of the central portion of the display surface of the peripheral characteristic amount detecting means corresponds to the characteristics of the peripheral portion detected, is obtained from the characteristics of pre-stored central, Store the acquired characteristic value of the central part together with a specific gradation level,
If it is not included, the central characteristic value is calculated with respect to the detected peripheral characteristic value based on the pre-stored central characteristic value and peripheral characteristic value, and the calculated central characteristic value is calculated. A computer program for storing a quantity together with a specific gradation level . On the computer,
A characteristic amount close to the characteristic amount detected by the peripheral characteristic amount detection unit is obtained from the characteristic amount of the central portion of the display surface and the characteristic amount of the peripheral portion that are discretely stored in advance, and an interpolation process is performed to obtain a central portion. The computer program product according to claim 16, wherein the characteristic amount of is calculated. On the computer,
18. The peripheral characteristic amount detection means converts the characteristic amount of the peripheral portion of the display surface detected as chromaticities of the three primary colors of red, green, and blue into tristimulus values. Computer program. On the computer,
The central characteristic amount detected by the central characteristic amount detection unit that detects the characteristic amount of the central portion of the display surface and the peripheral characteristic amount detected by the peripheral characteristic amount detection unit are stored in association with each other. The computer program according to any one of claims 16 to 18. On the computer,
The computer program according to any one of claims 16 to 19, wherein a display characteristic when displaying an image on the display surface is adjusted according to the acquired or calculated characteristic amount of the central part. .

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