JP5026545B2 - Display device, luminance unevenness correction method, correction data creation device, and correction data creation method - Google Patents

Description

  The present invention relates to a technique for correcting luminance unevenness on a display screen of a display device.

  In an image display device such as a liquid crystal display device, a plasma display, or an organic EL display, the brightness unevenness in which the display brightness on the screen is locally darker or brighter than the desired brightness due to various reasons in the manufacturing process. May occur.

  Brightness unevenness is classified into several types according to its shape, but typical ones are streaky unevenness that causes streaky luminance unevenness on the display screen, and spots that cause uneven brightness unevenness locally. There is unevenness.

  For example, in the manufacturing process of small high-definition liquid crystal panels, after depositing amorphous silicon on a glass substrate, laser irradiation is used to crystallize amorphous silicon with low mobility and change it to polysilicon with high mobility. If the intensity distribution of the laser is uneven, the polysilicon characteristics are uneven along the laser scanning direction, causing streaky unevenness. In addition, various parasitic capacitances exist in the display device, and stripe-like unevenness may occur due to variations in the parasitic capacitance value for each line such as a signal line.

  In addition, for example, the spot-like unevenness includes, for example, that the cell thickness of the display panel is locally different from the surroundings, the TFT characteristics are locally different, the electrode pattern dimensions are locally different, and alignment film pinholes are locally present It is caused by a cause such as contaminated foreign matter being locally mixed.

  As a method of correcting the luminance unevenness, for example, in Patent Document 1, in order to correct the luminance unevenness caused by the difference in the amount of light emitted from the backlight according to the distance from the backlight in the liquid crystal display device, It is described that luminance unevenness is corrected by multiplying a video signal by a coefficient corresponding to the distance from the backlight.

JP 2000-253277 A (published on September 14, 2000)

  However, since the technique of Patent Document 1 uniformly corrects the pixels belonging to the vertical line in accordance with the distance from the backlight, it cannot correct the uneven brightness locally generated on the display panel. .

  Further, the capacity of the nonvolatile memory that can be mounted in the liquid crystal driver of the small liquid crystal panel is generally very small. However, the correction data for correcting the luminance unevenness locally generated on the liquid crystal panel has a large capacity, so that it is usually difficult to store it in a small capacity nonvolatile memory.

  The present invention has been made in view of the above problems, and an object of the present invention is to appropriately correct luminance unevenness locally generated on a display panel using a nonvolatile memory having a very small capacity. is there.

In order to solve the above problems, a display device according to the present invention provides
A display device comprising: a display screen for displaying an image according to display image data; and a drive control unit for controlling a display state of each pixel of the display screen,
When an image corresponding to the inspection image data is displayed on the display screen, at least one of the luminance unevenness areas, which is an area where an image having a luminance value different from the appropriate luminance value corresponding to the inspection image data is displayed. In the display unevenness region, the difference between the brightness value when the image corresponding to the display image data is displayed and the appropriate brightness value corresponding to the display image data is reduced in the display image data. Created based on the inspection image data for correcting pixel data included in a correction area that is an area corresponding to the at least part of the uneven brightness area or an area including the uneven brightness area and its peripheral area. A correction data storage unit for storing the corrected data;
When an image corresponding to the display image data is displayed on the display screen, at least some of the pixels included in the correction area based on the correction data stored in the correction data storage unit. An image data correction unit for correcting the display image data so as to change the gradation value;
The correction data includes a luminance value of each pixel group obtained by dividing a plurality of pixels for each group of pixels when the image corresponding to the inspection image data is displayed on the display screen, and the inspection image data. A correction area corresponding to each luminance unevenness region is grouped according to a variation value of the luminance unevenness amount which is a difference from the appropriate luminance value of each corresponding pixel or each pixel group and the degree of luminance unevenness in each luminance unevenness region. The divided group information and the correction information indicating the content of correction for each group associated with the group information are included.
The image data correction unit determines a pixel whose gradation value is changed in each correction region based on a grouping result for each correction region, and the drive control unit is corrected by the image data correction unit. The display state of each pixel is controlled so that an image corresponding to the display image data is displayed.

  According to the above configuration, when an image corresponding to the inspection image data is displayed on the display screen, luminance unevenness that is an area in which an image having a luminance value different from the appropriate luminance value corresponding to the inspection image data is displayed. Display at least a part of the uneven luminance region of the region so as to reduce the difference between the luminance value when displaying an image corresponding to the display image data and the appropriate luminance value corresponding to the display image data. Based on the inspection image data for correcting pixel data included in a correction area, which is an area corresponding to the at least part of the luminance unevenness area in the image data or an area including the luminance unevenness area and its peripheral area The correction data created in this manner is stored in the correction data storage unit, and when the image corresponding to the display image data is displayed on the display screen, the image data correction unit Correcting the display image data so as to change the tone value of at least some pixels of the pixels included in the correction area based on the correction data stored in the data storage unit. The correction data includes the luminance value of each pixel or each pixel group obtained by dividing each pixel into a plurality of pixels when the image corresponding to the inspection image data is displayed on the display screen, and the inspection data. Correction corresponding to each luminance unevenness region according to the variation value of the luminance unevenness amount that is a difference from the appropriate luminance value of each pixel or each pixel group corresponding to the image data and the degree of luminance unevenness in each luminance unevenness region It includes group information in which areas are grouped, and correction information indicating the contents of correction for each group associated with the group information. The image data correction unit changes the gradation value in each correction area. The pixel to be determined is determined based on the grouping result for each correction region.

  In this way, the correction area is grouped based on the variation value of the luminance unevenness, and the pixels for correcting the gradation value are determined according to the grouping result, so that the brightness of each correction area can be determined without performing grouping. The amount of correction data can be reduced as compared with the case where a pixel for correcting a gradation value is calculated for each correction area in accordance with the amount of unevenness. In addition to the group information, the correction data includes correction information indicating the correction contents for each group associated with the group information. Therefore, by defining the correction information in advance using, for example, bit representations of [0] and [1], the correction data is further compared with the case where the content of correcting the gradation value is determined for each correction area. Data volume can be reduced. Therefore, the storage capacity of the correction data storage unit can be reduced, and a nonvolatile memory with a small storage capacity can be used as the correction data storage unit.

  In addition, the luminance unevenness varies greatly from display screen to display screen. By performing grouping based on the variation value of the brightness unevenness, even if the brightness unevenness varies from display screen to display screen, each correction area on each display screen Can be grouped according to the luminance unevenness amount of each display screen. Therefore, it is possible to appropriately correct the luminance unevenness locally generated on the display screen according to the degree of the luminance unevenness of each display screen.

In order to solve the above problems, a display device according to the present invention provides
A display device comprising: a display screen for displaying an image according to display image data; and a drive control unit for controlling a display state of each pixel of the display screen,
When an image corresponding to the inspection image data is displayed on the display screen, at least one of the luminance unevenness areas, which is an area where an image having a luminance value different from the appropriate luminance value corresponding to the inspection image data is displayed. In the display unevenness region, the difference between the brightness value when the image corresponding to the display image data is displayed and the appropriate brightness value corresponding to the display image data is reduced in the display image data. Created based on the inspection image data for correcting pixel data included in a correction area that is an area corresponding to the at least part of the uneven brightness area or an area including the uneven brightness area and its peripheral area. A correction data storage unit for storing the corrected data;
When an image corresponding to the display image data is displayed on the display screen, at least some of the pixels included in the correction area based on the correction data stored in the correction data storage unit. An image data correction unit for correcting the display image data so as to change the gradation value;
In the correction data, basic correction pattern information indicating one or a plurality of basic correction patterns that predetermine which of the pixels included in an area of a predetermined size is to be changed, and the display The screen is divided into a plurality of areas, and coordinate information indicating coordinates for arranging the basic correction pattern for each of the divided areas is included.
The image data correction unit is characterized in that a pixel whose gradation value is changed in each correction region is determined by combining the basic correction patterns.

  According to the above configuration, the basic correction pattern information indicating one or a plurality of basic correction patterns in which the gradation value of a pixel included in a region of a predetermined size is to be changed is corrected data. The pixel that corrects the gradation value for each correction area according to the luminance unevenness amount of each correction area without using the basic correction pattern by determining the pixel that changes the gradation value based on the pixel. The amount of correction data can be reduced compared to the case of calculating. Further, by selecting a basic correction pattern corresponding to the variation value of the luminance unevenness amount in each correction area, it is possible to appropriately correct the luminance unevenness locally generated on the display screen according to the luminance unevenness amount. In addition, the correction data includes coordinate information indicating coordinates for dividing the display screen into a plurality of areas and arranging the basic correction pattern for each of the divided areas, in addition to the basic correction pattern information. Yes. Therefore, by dividing the display screen into a plurality of regions, the amount of correction data for specifying the coordinates can be reduced, so that the amount of correction data can be further reduced.

In the display device according to the present invention,
The correction information includes correction necessity information indicating whether correction is to be performed, and, for the pixel group to be corrected, whether the correction is to increase or decrease the gradation value of at least some of the pixels. It is preferable that the correction gradation information shown is included.

  According to the above configuration, the correction information includes correction necessity information and correction gradation information. Therefore, when a pixel group that performs correction and a pixel group that does not perform correction coexist, correction gradation information for the pixel group that does not perform correction becomes unnecessary, and as a result, the amount of correction data can be further reduced. Therefore, the storage capacity of the correction data storage unit can be reduced, and a nonvolatile memory with a small storage capacity can be used as the correction data storage unit.

In the display device according to the present invention,
When correction for increasing or decreasing the gradation value of a pixel is continuously performed in adjacent pixel groups,
The correction gradation information is given only to the pixel group to be corrected first among the adjacent pixel groups, and other pixel groups are corrected with reference to the correction gradation information. Is preferred.

  According to the above configuration, the correction gradation information is given only to the pixel group to be corrected first among the adjacent pixel groups, and correction is performed with reference to the correction gradation information. It is not necessary to give the corrected gradation information to other pixel groups.

  Therefore, the amount of correction data can be further reduced, the storage capacity of the correction data storage unit can be reduced, and a nonvolatile memory with a small storage capacity can be used as the correction data storage unit.

In the display device according to the present invention,
When pixel groups that do not perform correction are continuous,
It is preferable that the correction information given to the first pixel group that is not corrected includes information indicating how many pixel groups that are not corrected continue.

  According to said structure, the information which shows how many pixel groups which do not perform correction | amendment is contained in the said correction information given to the first pixel group which does not perform correction | amendment. That is, it is not necessary to give non-correction information indicating that correction is not performed to the subsequent pixel group.

  Therefore, the amount of correction data can be further reduced, the storage capacity of the correction data storage unit can be reduced, and a nonvolatile memory with a small storage capacity can be used as the correction data storage unit.

  Note that the above configuration is a very effective data reduction method particularly when there are many consecutive uncorrected pixel groups on the display screen.

In the display device according to the present invention,
It is preferable that the display screen is divided into a plurality of areas, and the correction information is given to each of the divided areas.

  With the above configuration, for example, in the case where information indicating whether or not correction is performed is included in the correction information, if correction is not performed, other information indicating the content of the correction is unnecessary, and as a result, The data amount of all correction data can be reduced. That is, the configuration described above has an effect that the amount of correction data can be reduced.

In order to solve the above problems, the luminance unevenness correction method according to the present invention is as follows.
A brightness unevenness correction method for correcting brightness unevenness of the display screen in a display device including a display screen for displaying an image according to display image data,
When an image corresponding to the inspection image data is displayed on the display screen, at least one of the luminance unevenness areas, which is an area where an image having a luminance value different from the appropriate luminance value corresponding to the inspection image data is displayed. In the display unevenness region, the difference between the brightness value when the image corresponding to the display image data is displayed and the appropriate brightness value corresponding to the display image data is reduced in the display image data. Created based on the inspection image data for correcting pixel data included in a correction area that is an area corresponding to the at least part of the uneven brightness area or an area including the uneven brightness area and the surrounding area. A correction data storage step for storing correction data;
When an image corresponding to the display image data is displayed on the display screen, at least some of the pixels included in the correction area based on the correction data stored in the correction data storage unit. An image data correction step for correcting the display image data so as to change the gradation value;
A drive control step of controlling the display state of each pixel so as to display an image according to the display image data corrected by the image data correction step,
The correction data includes a luminance value of each pixel group obtained by dividing a plurality of pixels for each group of pixels when the image corresponding to the inspection image data is displayed on the display screen, and the inspection image data. A correction area corresponding to each luminance unevenness region is grouped according to a variation value of the luminance unevenness amount which is a difference from the appropriate luminance value of each corresponding pixel or each pixel group and the degree of luminance unevenness in each luminance unevenness region. The divided group information and the correction information indicating the content of correction for each group associated with the group information are included.
The image data correction step is characterized in that a pixel whose gradation value is changed in each correction area is determined based on a grouping result for each correction area.

  According to the above method, the correction area is grouped based on the variation value of the luminance unevenness, and the pixels for correcting the gradation value are determined according to the grouping result, so that each correction is performed without performing grouping. The amount of correction data can be reduced as compared with the case where a pixel for correcting a gradation value is set for each correction region according to the amount of luminance unevenness in the region. Therefore, the storage capacity of the storage means for storing the correction data can be reduced, and a nonvolatile memory with a small storage capacity can be used as the storage means.

  In addition, the luminance unevenness varies greatly from display screen to display screen. By performing grouping based on the variation value of the brightness unevenness, even if the brightness unevenness varies from display screen to display screen, each correction area on each display screen Can be grouped according to the luminance unevenness amount of each display screen. Therefore, it is possible to appropriately correct the luminance unevenness locally generated on the display screen according to the degree of the luminance unevenness of each display screen.

In order to solve the above problems, the luminance unevenness correction method according to the present invention is as follows.
A brightness unevenness correction method for correcting brightness unevenness of the display screen in a display device including a display screen for displaying an image according to display image data,
When an image corresponding to the inspection image data is displayed on the display screen, at least one of the luminance unevenness areas, which is an area where an image having a luminance value different from the appropriate luminance value corresponding to the inspection image data is displayed. In the display unevenness region, the difference between the brightness value when the image corresponding to the display image data is displayed and the appropriate brightness value corresponding to the display image data is reduced in the display image data. Created based on the inspection image data for correcting pixel data included in a correction area that is an area corresponding to the at least part of the uneven brightness area or an area including the uneven brightness area and the surrounding area. A correction data storage step for storing correction data;
When displaying an image corresponding to the display image data on the display screen, the gradation of at least some of the pixels included in the correction area based on the correction data stored in the correction data storage step An image data correction step for correcting the display image data so as to change the value;
A drive control step of controlling the display state of each pixel so as to display an image according to the display image data corrected by the image data correction step,
The correction data includes basic correction pattern information for specifying one or a plurality of basic correction patterns, which are predetermined for changing the gradation value of a pixel included in an area of a predetermined size. , The display screen is divided into a plurality of areas, and for each of the divided areas, coordinate information indicating coordinates for arranging the basic correction pattern is included,
In the image data correction step, a pixel whose gradation value is changed in each correction region is determined by combining the basic correction patterns specified by the basic correction pattern information.

  According to the above method, the basic correction pattern information indicating one or a plurality of basic correction patterns in which the gradation value of a pixel included in a region of a predetermined size is to be changed is corrected data. And determining the pixel whose gradation value is to be changed based on the pixel, and correcting the gradation value for each correction area according to the luminance unevenness amount of each correction area without using the basic correction pattern. The amount of correction data can be reduced compared to the case of calculation. Further, by selecting a basic correction pattern corresponding to the variation value of the luminance unevenness amount in each correction area, it is possible to appropriately correct the luminance unevenness locally generated on the display screen according to the luminance unevenness amount.

In order to solve the above-described problem, the correction data creation device according to the present invention provides:
A correction data creation device that creates the correction data to be stored in the correction data storage unit in the display device described above,
The luminance value of each pixel in the imaging data obtained by imaging the display screen in a state where an image corresponding to the inspection image data is displayed, or the luminance value of each pixel group obtained by dividing each pixel into a plurality of pixels An area composed of a set of pixels or pixel groups in which the difference from the appropriate luminance value corresponding to the inspection image data based on the moving average value is calculated, and the calculated magnitude of the difference is greater than or equal to a predetermined threshold value A brightness unevenness detecting unit for detecting the brightness unevenness area,
For at least some of the brightness unevenness areas, the difference between the brightness value when displaying an image corresponding to the display image data and the appropriate brightness value corresponding to the display image data is reduced. As described above, correction data for correcting pixel data included in a correction area that is an area corresponding to the at least part of the luminance unevenness area in the display image data or an area including the luminance unevenness area and its peripheral area. And a correction data generation unit for creating the image data based on the inspection image data,
The correction data generation unit
Each pixel corresponding to the inspection image data and the luminance value of each pixel or each pixel group obtained by dividing each pixel into a plurality of pixels when the image corresponding to the inspection image data is displayed on the display screen Alternatively, group information in which correction areas corresponding to each luminance unevenness region are grouped according to the variation value of the luminance unevenness amount that is a difference from the appropriate luminance value of each pixel group and the degree of luminance unevenness in each luminance unevenness region, and The correction data includes correction information associated with the group information and indicating the correction contents for each group.

In addition, the correction data creation method according to the present invention is to solve the above problems,
A correction data creation method for creating the correction data to be stored in the correction data storage unit in the display device described above,
Displaying an image corresponding to the image data for inspection on the display screen;
Imaging the display screen in a state where an image corresponding to the inspection image data is displayed, and obtaining imaging data;
Calculates the difference between the luminance value of each pixel in the imaging data or the luminance value of each pixel group obtained by dividing each pixel into a plurality of pixels and the appropriate luminance value corresponding to the inspection image data based on the moving average value A luminance unevenness detecting step of detecting, as a luminance unevenness region, a region composed of a set of pixels or pixel groups in which the calculated magnitude of the difference is equal to or greater than a predetermined threshold;
For at least some of the brightness unevenness areas, the difference between the brightness value when displaying an image corresponding to the display image data and the appropriate brightness value corresponding to the display image data is reduced. As described above, correction data for correcting pixel data included in a correction area that is an area corresponding to the at least part of the luminance unevenness area in the display image data or an area including the luminance unevenness area and its peripheral area. Including a correction data generation step for creating a correction data based on the inspection image data,
In the correction data generation step,
Each pixel corresponding to the inspection image data and the luminance value of each pixel or each pixel group obtained by dividing each pixel into a plurality of pixels when the image corresponding to the inspection image data is displayed on the display screen Alternatively, group information in which correction areas corresponding to each luminance unevenness region are grouped according to the variation value of the luminance unevenness amount that is a difference from the appropriate luminance value of each pixel group and the degree of luminance unevenness in each luminance unevenness region, and The correction data includes correction information associated with the group information and indicating the correction contents for each group.

  According to the correction data generation device and the correction data generation method, correction data including group information can be generated. Therefore, luminance unevenness can be appropriately corrected using the correction data in the display device. Compared with the case where correction data not including group information is used, the correction data includes a condition for setting pixels for correcting gradation values in consideration of the luminance unevenness of each correction area for each correction area in the display device. Therefore, the data size of the correction data can be reduced. In addition, in addition to the group information, the correction data includes correction information indicating the correction contents for each group associated with the group information. Therefore, by defining the correction information in advance using, for example, bit representations of [0] and [1], the correction data is further compared with the case where the content of correcting the gradation value is determined for each correction area. Data volume can be reduced. Therefore, the storage capacity of the correction data storage unit provided in the display device can be reduced.

In addition, in order to solve the above problems, the correction data creation device according to the present invention,
A correction data creation device that creates the correction data to be stored in the correction data storage unit in the display device described above,
The luminance value of each pixel in the imaging data obtained by imaging the display screen in a state where an image corresponding to the inspection image data is displayed, or the luminance value of each pixel group obtained by dividing each pixel into a plurality of pixels An area composed of a set of pixels or pixel groups in which the difference from the appropriate luminance value corresponding to the inspection image data based on the moving average value is calculated, and the calculated magnitude of the difference is greater than or equal to a predetermined threshold value A brightness unevenness detecting unit for detecting the brightness unevenness area,
For at least some of the brightness unevenness areas, the difference between the brightness value when displaying an image corresponding to the display image data and the appropriate brightness value corresponding to the display image data is reduced. As described above, correction data for correcting pixel data included in a correction area that is an area corresponding to the at least part of the luminance unevenness area in the display image data or an area including the luminance unevenness area and its peripheral area. And a correction data generation unit for creating the image data based on the inspection image data,
The correction data generation unit
A plurality of basic correction pattern information for specifying one or a plurality of basic correction patterns that predetermine which of the pixels included in an area of a predetermined size is to be changed, and a plurality of the display screens; The correction data includes coordinate information indicating coordinates for arranging the basic correction pattern for each of the divided areas.

In addition, the correction data creation method according to the present invention is to solve the above problems,
A correction data creation method for creating the correction data to be stored in the correction data storage unit in the display device described above,
Displaying an image corresponding to the image data for inspection on the display screen;
Imaging the display screen in a state where an image corresponding to the inspection image data is displayed, and obtaining imaging data;
Calculates the difference between the luminance value of each pixel in the imaging data or the luminance value of each pixel group obtained by dividing each pixel into a plurality of pixels and the appropriate luminance value corresponding to the inspection image data based on the moving average value A luminance unevenness detecting step of detecting, as a luminance unevenness region, a region composed of a set of pixels or pixel groups in which the calculated magnitude of the difference is equal to or greater than a predetermined threshold;
For at least some of the brightness unevenness areas, the difference between the brightness value when displaying an image corresponding to the display image data and the appropriate brightness value corresponding to the display image data is reduced. As described above, correction data for correcting pixel data included in a correction area that is an area corresponding to the at least part of the luminance unevenness area in the display image data or an area including the luminance unevenness area and its peripheral area. Including a correction data generation step for creating a correction data based on the inspection image data,
In the correction data generation step,
A plurality of basic correction pattern information for specifying one or a plurality of basic correction patterns that predetermine which of the pixels included in an area of a predetermined size is to be changed, and a plurality of the display screens; The correction data includes coordinate information indicating coordinates for arranging the basic correction pattern for each of the divided areas.

  According to the correction data generation apparatus and the correction data generation method, one or a plurality of basic correction patterns that determine in advance which of the pixels included in a region of a predetermined size is to be changed are obtained. Since correction data including basic correction pattern information for specifying can be created, luminance unevenness can be appropriately corrected using the correction data in the display device using the basic correction pattern. Further, by using the basic correction pattern, it is not necessary to include in the correction data conditions for calculating pixels for correcting gradation values in consideration of the luminance unevenness amount of each correction area for each correction area in the display device. The data size of the correction data can be reduced. In addition, the correction data includes coordinate information indicating coordinates for dividing the display screen into a plurality of areas and arranging the basic correction pattern for each of the divided areas, in addition to the basic correction pattern information. Yes. Therefore, the storage capacity of the correction data storage unit provided in the display device can be reduced.

As described above, the display device according to the present invention is
When an image corresponding to the inspection image data is displayed on the display screen, at least one of the luminance unevenness areas, which is an area where an image having a luminance value different from the appropriate luminance value corresponding to the inspection image data is displayed. In the display unevenness region, the difference between the brightness value when the image corresponding to the display image data is displayed and the appropriate brightness value corresponding to the display image data is reduced in the display image data. Created based on the inspection image data for correcting pixel data included in a correction area that is an area corresponding to the at least part of the uneven brightness area or an area including the uneven brightness area and its peripheral area. A correction data storage unit for storing the corrected data;
When an image corresponding to the display image data is displayed on the display screen, at least some of the pixels included in the correction area based on the correction data stored in the correction data storage unit. An image data correction unit for correcting the display image data so as to change the gradation value;
The correction data includes a luminance value of each pixel group obtained by dividing a plurality of pixels for each group of pixels when the image corresponding to the inspection image data is displayed on the display screen, and the inspection image data. A correction area corresponding to each luminance unevenness region is grouped according to a variation value of the luminance unevenness amount which is a difference from the appropriate luminance value of each corresponding pixel or each pixel group and the degree of luminance unevenness in each luminance unevenness region. The divided group information and the correction information indicating the content of correction for each group associated with the group information are included.
The image data correction unit determines a pixel whose gradation value is changed in each correction region based on a grouping result for each correction region,
The drive control unit is configured to control the display state of each pixel so that an image corresponding to the display image data corrected by the image data correction unit is displayed.

Moreover, the display device according to the present invention includes:
When an image corresponding to the inspection image data is displayed on the display screen, at least one of the luminance unevenness areas, which is an area where an image having a luminance value different from the appropriate luminance value corresponding to the inspection image data is displayed. In the display unevenness region, the difference between the brightness value when the image corresponding to the display image data is displayed and the appropriate brightness value corresponding to the display image data is reduced in the display image data. Created based on the inspection image data for correcting pixel data included in a correction area that is an area corresponding to the at least part of the uneven brightness area or an area including the uneven brightness area and its peripheral area. A correction data storage unit for storing the corrected data;
When an image corresponding to the display image data is displayed on the display screen, at least some of the pixels included in the correction area based on the correction data stored in the correction data storage unit. An image data correction unit for correcting the display image data so as to change the gradation value;
In the correction data, basic correction pattern information indicating one or a plurality of basic correction patterns that predetermine which of the pixels included in an area of a predetermined size is to be changed, and the display The screen is divided into a plurality of areas, and coordinate information indicating coordinates for arranging the basic correction pattern for each of the divided areas is included.
The image data correction unit is configured to determine a pixel whose gradation value is changed in each correction region by combining the basic correction patterns.

  Therefore, it is possible to appropriately correct the luminance unevenness of the display screen using a nonvolatile memory having a small capacity.

It is explanatory drawing which shows the correction method of the image data in the display apparatus concerning one Embodiment of this invention. It is a block diagram which shows the structure of the correction data production apparatus concerning one Embodiment of this invention. FIG. 3 is a graph showing an example of luminance data extracted from imaging data and a moving average value calculated from the luminance data in the correction data creation apparatus shown in FIG. 2. FIG. 4 is a graph showing luminance data obtained by removing the influence of slowly varying luminance unevenness such as luminance unevenness caused by a backlight from the luminance data shown in FIG. 3 and an average luminance of a display screen. It is explanatory drawing for demonstrating the production | generation method of the correction information in the correction data production apparatus shown in FIG. It is explanatory drawing for demonstrating the production | generation method of the correction information in the correction data production apparatus shown in FIG. It is explanatory drawing which shows an example of the correction pixel (adjustment correction pixel) and the pixel which is not correct | amended (pixels other than an adjustment correction pixel) in the correction data produced | generated in the correction data production apparatus shown in FIG. 3 is a graph showing an example of luminance data extracted from imaging data, a moving average value calculated from the luminance data, and an average value of all luminances in the correction data creation device shown in FIG. 2. It is explanatory drawing for demonstrating the production | generation method of the correction information in the correction data production apparatus shown in FIG. It is a flowchart for demonstrating the method to describe the correction information obtained in the correction data production apparatus shown in FIG. 2 as correction data. It is a flowchart for demonstrating the method to describe the correction information obtained in the correction data production apparatus shown in FIG. 2 as correction data. It is a flowchart for demonstrating the method to describe the correction information obtained in the correction data production apparatus shown in FIG. 2 as correction data. It is a block diagram which shows the structure of the drive control part with which the display apparatus concerning one Embodiment of this invention is equipped. It is explanatory drawing which shows an example of the correction pattern set in the drive control part shown in FIG. It is a graph which shows the brightness | luminance data before and behind a brightness nonuniformity correction process. It is a block diagram which shows the structure of the correction data production apparatus concerning other embodiment of this invention. It is a figure which shows the concept of the correction method of spotted unevenness. It is a block diagram which shows the structure of the drive control part with which the display apparatus concerning other embodiment of this invention is equipped. It is a figure which shows the dither matrix of R, G, B each color of a magnitude | size of 4x4. It is a figure which shows the basic correction pattern which has a magnitude | size of 4 pixels x 4 pixels. It is a figure which shows the correction pattern which showed how to combine the basic correction pattern shown in FIG. It is explanatory drawing which shows an example of the setting method of the correction pattern in the drive control part shown in FIG. It is a block diagram which shows the structure of the correction data production apparatus concerning further another embodiment of this invention. It is a block diagram which shows the structure of the drive control part with which the display apparatus concerning further another embodiment of this invention is equipped.

Embodiment 1
An embodiment of the present invention will be described. In the present embodiment, a source in a transmissive liquid crystal display device provided in a mobile device such as a mobile phone, which displays based on image data expressing each color of RGB in 6 bits. An example of correcting the stripe unevenness in the direction parallel to the extending direction of the line (data line) will be mainly described. However, the application target of the present invention is not limited to this.

  FIG. 2 is a block diagram showing a configuration of the correction data creation apparatus 10 according to the present embodiment. As shown in this figure, the correction data creation device 10 includes a display data generation unit 11, an imaging unit 12, a luminance data extraction unit 13, a moving average processing unit 14, a luminance unevenness detection unit 15, and a correction data generation unit 16. I have.

  The display data generation unit 11 generates display data to be displayed on the display panel and outputs it to the drive control unit 22 of the display panel 21 when the display panel 21 is inspected for luminance unevenness. In general, luminance unevenness is likely to be visually recognized when a halftone image is uniformly displayed on the entire surface with the same gradation. For this reason, in the present embodiment, the display data generation unit 11 obtains inspection image data, which is image data for displaying a halftone image of the same gradation on all pixels of the display panel in order to detect luminance unevenness. Generate.

  The imaging unit 12 acquires imaging data by imaging the display surface of the display panel 21 on which an image corresponding to the inspection image data generated by the display data generation unit 11 is displayed. As the imaging unit 12, for example, a CCD camera or the like can be used.

  The luminance data extraction unit 13 extracts luminance data from the imaging data acquired by the imaging unit 12.

  The moving average processing unit 14 is a set of pixels in a region corresponding to the source line of the display screen in the luminance data extracted by the luminance data extracting unit 13 (or a region having a predetermined width parallel to the extending direction of the source line). For the line pixel group, the average value of the luminance of each pixel included in the line pixel group is calculated as the luminance value of the line pixel group. In addition, the moving average processing unit 14 determines the luminance value of each line pixel group as a peripheral region within a predetermined range including the line pixel group (for example, perpendicular to the extending direction of the line pixel group centered on the line pixel group). A moving average process is performed to calculate a moving average value averaged with the luminance value of each pixel included in a 3 mm wide area in a specific direction.

  Note that the display data generation unit 11, the luminance data extraction unit 13, the moving average processing unit 14, the luminance unevenness detection unit 15, and the correction data generation unit 16 in FIG. 2 do not have to be independent circuits. The generation device 10 only needs to have these functions. For example, all of these arithmetic functions can be performed by a CPU of a personal computer. That is, the correction data generation device 10 can be formed by connecting a digital camera as the imaging unit 12 and a personal computer for performing the above-described calculation functions.

  The solid line in FIG. 3 is a graph showing the luminance value of each line pixel group calculated based on the luminance data extracted by the luminance data extraction unit 13, and the broken line shows the moving average value of the luminance value of each line pixel group. It is a graph. The moving average value is obtained in order to remove moderate luminance unevenness such as luminance unevenness caused by the backlight and to extract local luminance unevenness that is easily recognized as unevenness, and indicates luminance in a state without unevenness. . The solid line in FIG. 4 is obtained by adding the average value of panel luminance (average value of luminance of the entire display screen) to the value obtained by subtracting the moving average value from the luminance value of each line pixel group in FIG. It is a graph which shows the luminance value of each line pixel group after removing the influence of the luminance unevenness which changes gradually, such as the luminance unevenness resulting from light, and a broken line is a graph which shows the average value of panel luminance. In these graphs, the horizontal axis indicates the position of each line pixel group, and the vertical axis indicates the luminance value of each line pixel group (the average value of the luminance values of pixels belonging to each line pixel group).

  The luminance unevenness detection unit 15 detects a region where luminance unevenness occurs based on the luminance value of each line pixel group extracted from the imaging data by the luminance data extraction unit 13 and the moving average value thereof.

  Specifically, the luminance unevenness detection unit 15 calculates the difference between the luminance value of each line pixel group in the luminance data extracted from the imaging data by the luminance data extraction unit 13 and the moving average value, and calculates the difference between the calculated differences. A region composed of a set of line pixel groups having an absolute value equal to or greater than a predetermined threshold is detected as luminance unevenness (luminance unevenness region). In other words, the moving average value of the luminance values of each line pixel group is regarded as an appropriate luminance value when no luminance unevenness has occurred for each line pixel group, and is compared with the luminance value of each line pixel group. Detects the area where is occurring. Thereby, it is possible to appropriately detect luminance unevenness by removing the influence of the backlight and the like.

  That is, in a transmissive liquid crystal display device, a diffusion plate or the like is generally provided to uniformly irradiate the display panel with light emitted from the backlight, but it is difficult to make the display panel uniform uniformly. Depending on the position, there may be a difference in the brightness of the light emitted from the backlight. However, since the luminance distribution due to the relative position with respect to the backlight changes relatively gently over a wide range of the display panel (see the inclination of the broken line portion in FIG. 3), it is rarely recognized as luminance unevenness. In other words, it is recognized that the brightness is uneven in the human eye when the brightness is greatly changed locally, and is recognized as uneven when the brightness is continuously changing with a large spatial period. It is hard to be done. For this reason, the difference in luminance caused by the luminance distribution of the irradiation light from the backlight is rarely recognized as luminance unevenness.

  On the other hand, if the brightness value of the appropriate area where brightness unevenness does not occur without considering the influence of the backlight is regarded as a constant value for all areas of the display screen, an area that is not visually recognized as brightness unevenness may be detected as brightness unevenness. In some cases, an area that is visually recognized as luminance unevenness is detected as an appropriate area. That is, the luminance value (appropriate luminance value) of the appropriate area where the luminance unevenness does not occur differs depending on the position on the display panel.

  Therefore, in the present embodiment, the moving average processing unit 14 performs the moving averaging process on the luminance data extracted by the luminance data extracting unit 13, and the moving average value of the luminance value of each line pixel group is set to each line pixel. It is regarded as a luminance value (appropriate luminance value) when the group is an appropriate region. This eliminates the influence of the luminance distribution of the illumination light from the backlight, and appropriately and easily detects an area where the difference from the brightness of the adjacent area, which is easily visible as an uneven brightness, changes rapidly. be able to.

  Luminance unevenness detection using a moving average can effectively detect luminance unevenness that is easily recognized by the human eye, and can be processed at high speed because it does not require complicated analysis calculation. High throughput can be realized using a computing device.

  Note that the range to be averaged in the moving averaging process (the range in the direction perpendicular to the extending direction of the line pixel group) is sufficiently wider than the width of the stripe-like luminance unevenness region, and the backlight at each position within the range. It is preferable to set the difference in the luminance value of the irradiation light from within a range where the luminance value in the luminance unevenness region is sufficiently small with respect to the deviation from the appropriate luminance value.

  When the range to be averaged by the moving average process is too small, luminance unevenness that is easily visible cannot be detected sufficiently when the difference between the luminance of each line pixel group and the moving average value is taken. This is because the luminance unevenness distribution of the individual line pixel groups is excessively reflected in the moving average value distribution.

  On the other hand, if the range averaged by the moving average process is too wide, even brightness unevenness caused by a backlight that is difficult to be visually recognized is detected as brightness unevenness. In this case, when data for correcting luminance unevenness is converted into data, the amount of data becomes very large, leading to an increase in cost. Therefore, in the case of a display panel of about several hundred pixels × several hundred pixels provided in a mobile device such as a cellular phone, it is preferable to set it within a range of 1 mm or more and 5 mm or less. By setting the appropriate luminance value, it is possible to effectively detect luminance unevenness visually recognized by the human naked eye. In this embodiment, the display panel 21 of 360 pixels × 480 pixels is used, and the above range is set to 3 mm.

  The correction data generation unit 16 generates correction data for making the luminance unevenness less visible based on the information on the luminance unevenness detected by the luminance unevenness detection unit 15. This correction data is output to the drive control unit 22 of the display device 20 and is stored in a storage unit inside the drive control unit 22, and the circuit in the drive control unit 22 displays image data of an image to be displayed. Can be processed based on the correction data, and an image can be displayed so that uneven brightness is not noticeable. That is, the correction data describes what correction is performed on which pixel on the display panel 21 with respect to the circuit of the drive control unit 22 and is based on the position of the uneven area to be corrected and the uneven intensity. Generated. In addition, when the difference between the peak value of the luminance value of the line pixel group included in the luminance unevenness region and the appropriate luminance value is less than a predetermined reference value, it is considered that no streaky luminance unevenness exists, The correction may not be given.

  In the present embodiment, as described above, the display device 20 that performs display based on image data expressing each color of RGB with 6 bits is used. In this type of low gradation panel, uneven brightness may not be corrected appropriately by simply adjusting the gradation of the display image data based on the detection result of uneven brightness. This is because the minimum value of the deviation of the luminance value recognized as luminance unevenness is less than the luminance value corresponding to one gradation in the display image data in the case of a 6-bit gradation panel. If the correction is made so that the data is increased by one gradation, the correction amount becomes too large to be visually recognized as bright luminance unevenness, or conversely, if the data is corrected to decrease by one gradation in order to correct the bright luminance unevenness, it is dark. This is because it may be visually recognized as luminance unevenness.

  Therefore, there is provided a method for correcting image data that makes it difficult to visually recognize luminance unevenness due to the luminance deviation even if the luminance deviation with respect to the appropriate luminance value is less than the luminance value corresponding to one gradation of the image data. It is necessary to take.

  FIG. 5 is an explanatory diagram for explaining a display unevenness analysis method for taking such a correction method. More specifically, FIG. 5 shows the display panel 21 in a state in which inspection image data having gradation values 9, 10, and 11 is displayed for each pixel, and an image corresponding to each gradation value is displayed. It is a graph which shows the luminance value of each line pixel group extracted based on the imaged imaging data, and the average value of panel luminance. Note that FIG. 5 shows the luminance value of each line pixel group after performing the same processing as in FIG. 4 and removing the influence of the luminance variation that gradually changes such as the luminance variation caused by the backlight.

  The luminance unevenness detection unit 15 detects, as luminance unevenness, a portion where the absolute value of the difference in luminance value (luminance unevenness amount) with respect to the appropriate luminance value in the luminance data extracted from the imaging data is equal to or greater than a predetermined threshold value. Specifically, a portion where the difference is a positive value and the absolute value is greater than or equal to the threshold is detected as bright unevenness, and a portion where the difference is a negative value and the absolute value is greater than or equal to the threshold is determined as dark unevenness. To detect. In the example of FIG. 5, the portions indicated by C1 and C2 are detected as bright luminance unevenness, and the portions indicated by D1 and D2 are detected as dark luminance unevenness.

  Next, the luminance unevenness detection unit 15 detects a difference between the value of each luminance unevenness portion and the appropriate luminance value. In the example of FIG. 5, differences c1, c2, d1, and d2 are detected for luminance unevenness C1, C2, D1, and D2, respectively.

  The luminance unevenness detection unit 15 also determines the difference A between the luminance value of the appropriate portion for the image data that is one gradation higher than the reference gradation value and the luminance value of the appropriate portion for the image data of the reference gradation value, and the reference gradation. The difference B between the luminance value of the appropriate part for the value image data and the luminance value of the appropriate part for the image data one gradation lower than the reference gradation value is detected.

  Then, the brightness unevenness detection unit 15 calculates the ratios c1 / B and c2 / B between the differences c1 and c2 and the difference B with respect to the brightness unevenness C1 and C2, and dark brightness unevenness D1. , D2, the ratios d1 / A and d2 / A between the differences d1, d2 and the difference A for the luminance unevenness are calculated.

  Based on these calculation results, an appropriate image data correction method is determined.

  When the ratio (c1 / B, c2 / B, etc.) for bright luminance unevenness is 1 or less, the proportion corresponding to the ratio for the luminance unevenness among pixels belonging to the line pixel group corresponding to the bright luminance unevenness By performing image data correction that lowers the display image data for one pixel (adjustment correction pixel) by one gradation, unevenness can be made difficult to be visually recognized.

  Further, when the ratio (c1 / B, c2 / B, etc.) exceeds 1, the display image data for the pixels belonging to the line pixel group corresponding to the bright luminance unevenness is a gradation value corresponding to the integer part of the ratio. The image data correction is performed so that the display image data for the pixels (adjustment correction pixels) at a ratio corresponding to the decimal part of the ratio is further lowered by one gradation, thereby making it difficult to visually recognize unevenness. be able to.

  However, if correction is actually made for each line pixel group based on the ratio (c1 / B, c2 / B, etc.), the value of the ratio of all line pixel groups is necessary for correction. Therefore, there is a possibility that the capacity of the memory for storing this becomes large and the correction calculation becomes complicated. Therefore, in the present embodiment, the correction is not performed directly based on the value of the unevenness ratio (c1 / B, c2 / B, etc.) as described above, but as a more preferable method, for each line pixel group, Based on the values of the above ratios (c1 / B, c2 / B, etc.), a method of grading based on unevenness intensity is used. This will be described with reference to FIG.

  FIG. 6 is a graph illustrating an example of a relationship between a position where bright luminance unevenness occurs and the value of the ratio for each luminance unevenness.

  As described above, the present embodiment is characterized by appropriately classifying the intensity of luminance unevenness in each line pixel group into several stages when determining a correction method from the result of luminance unevenness analysis. In the example of FIG. 6, classification is made into four stages. For example, when the ratio (c1 / B, c2 / B, etc.) is distributed between 0 and 0.50, the ratio is 0.10. The line pixel group of less than 0.20 is uneven intensity 1, the line pixel group of 0.20 or more and less than 0.30 is uneven intensity 2, the line pixel group of 0.30 or more and less than 0.40 is uneven intensity 3,. A group of line pixels from 40 to 0.50 is classified as unevenness intensity 4. Note that the values of the above ratios (c1 / B, c2 / B, etc.) are less than 0.10 and are ignored here because the unevenness is hardly noticeable.

  Then, a correction method for correcting this unevenness intensity is determined and assigned. In the example of FIG. 6, since the ratio (c1 / B, c2 / B, etc.) of the line pixel group classified as unevenness intensity 1 is 0.10 or more and less than 0.20, it is an intermediate value of 0.15. Is a representative ratio value of unevenness intensity 1. Similarly, the representative ratio values of the unevenness strengths 2, 3, and 4 are set to 0.25, 0.35, and 0.45, respectively. This representative ratio value is a value near the center of each stage, and so that the ratio between the numerator and the denominator is as simple as possible when expressed as a fraction (so that the value of the numerator and denominator is not so large) What is necessary is just to decide suitably. For example, instead of the above values as the values of the representative ratios for the unevenness intensity 1, 2, 3, 4, 1/7 (= ˜0.14), 1/4 (= 0.25), 1 / Values of 3 (= ˜0.33) and 1/2 (= 0.50) can also be used.

  Then, correction to each line pixel group may be performed using these representative ratio values. That is, for example, when the values of 1/7, 1/4, 1/3, and 1/2 are used as the values of the representative ratios for the unevenness strengths 1, 2, 3, and 4, the lines classified as unevenness strength 1 are used. For the pixel group, based on the representative ratio value 1/7, correction is performed to lower the gradation of the image data by one gradation at a ratio of one pixel to seven pixels. The unevenness intensities 2, 3 and 4 are also corrected so that the gradation of the image data is reduced by one gradation at a ratio of 1 pixel for 4 pixels, 1 pixel for 3 pixels, and 1 pixel for 2 pixels.

  FIG. 7 is an explanatory diagram illustrating an example of pixel positions where correction is performed on pixels in a line pixel group with uneven brightness corresponding to uneven intensity 2, and 1 in 4 pixels is included in the pixels included in the line pixel group. Correction is performed on the image data by reducing the gradation of the image data to be displayed by one pixel at the pixel ratio.

  In FIG. 7, among the pixels of the source line, the pixel at the top of the paper (the top pixel in the vertical direction in the drawing) is the correction pixel, and correction pixels are arranged every four pixels hereinafter. However, this is not necessarily the case, and it is important that the ratio of correction pixels is one in four pixels, and every four pixels may be corrected pixels in order from the second pixel from the top. Or from the fourth pixel. More preferably, the number of pixels from the top as the first correction pixel (offset amount) is preferably changed for each scan of the display screen. As a result, the specific pixels are not corrected, but the corrected pixels are dispersed in time, and the entire source line is subjected to correction for ¼ gradation so as to make the unevenness less visible. Can do.

  In the luminance unevenness region where the difference with respect to the appropriate luminance value (deviation from the appropriate luminance value) is large, the ratio of the pixels for correcting the display image data by one gradation is large, that is, the display image data is corrected by one gradation. Pixels become dense. On the other hand, in the luminance unevenness region where the difference with respect to the appropriate luminance value is relatively small, the ratio of the pixels for correcting the display image data by one gradation is small, that is, the pixels for correcting the display image data by one gradation are sparse. Become.

  By performing such correction on the image data, the luminance modulation due to the display unevenness can be canceled, so that the display unevenness can be made difficult to be visually recognized.

  The representative ratio value at each unevenness intensity level is 0.5 or less in the above example, but the same correction can be performed when it exceeds 0.5. For example, when the representative ratio value of a certain uneven intensity level is set to 3/5, the image data of the line pixel group belonging to that uneven intensity level may be lowered by one gradation with respect to 3 pixels out of 5 pixels. .

  Further, when the representative ratio value of a certain unevenness intensity level exceeds 1, for the line pixel group belonging to that unevenness intensity level, only the gradation value corresponding to the integer part of the representative ratio value is included in the pixels of the line pixel group. At the same time, the corresponding display image data is lowered uniformly, and the gradation of the corresponding display image data is further lowered by one gradation with respect to the pixels of the proportion corresponding to the decimal part of the representative ratio value. For example, for a line pixel group belonging to the unevenness intensity stage having a representative ratio value of 4/3, the display image data corresponding to the pixel of the line pixel group is lowered by one pixel per two pixels, two gradations, and the remaining These pixels may be lowered by one gradation.

  Alternatively, the following method may be used as a correction method when the representative ratio value at a certain uneven intensity level exceeds 1. That is, the ratio is divided by a number n of 2 or more that results in a division result of 1 or less when the ratio is divided, and the display image data for pixels (adjustment correction pixels) at a ratio corresponding to the division result is nth order. You may perform correction | amendment which makes it low. For example, when the representative ratio at a certain luminance unevenness intensity level is 1.25 (= 5/4), a value (5/4 ÷ 2 = 5/8) divided by n = 2 is calculated, and this division result In accordance with the above, it is possible to perform correction to lower two gradations at a ratio of 5 to 8 pixels.

  Although the correction method for bright luminance unevenness has been described above, correction for dark luminance unevenness can be similarly performed. That is, as described with reference to FIG. 5, each line pixel is also determined based on the values d1 / A, d2 / A... The brightness unevenness can be made inconspicuous by increasing the display image data of the pixels having this ratio by one gradation with respect to the pixels included in the group. However, as a more preferable embodiment, it is possible to adopt a method of performing the stage division based on the unevenness intensity even for the dark brightness unevenness.

  That is, the ratio (d1 / A, d2 / A, etc.) of each line pixel group is classified into appropriate stages of about four stages by the same method as in FIG. Then, a representative ratio value is set for each stage, and the display image data is corrected using the representative ratio value. Specifically, it may be performed based on the correction method for bright unevenness described above. In other words, the representative ratio value at each stage is an intermediate value at that stage, and a value such that the numerator and denominator have a simple integer ratio may be set, and the display image corresponding to the line pixel group belonging to that stage. The data of the pixel having a ratio corresponding to the representative ratio value may be increased by one gradation with respect to the data. In particular, when the representative ratio value of a certain unevenness level exceeds 1, the display image data corresponding to the pixels of the line pixel group is uniformly increased by the gradation value corresponding to the integer part of the representative ratio value, The gradation of the corresponding display image data may be further increased by one gradation with respect to the ratio of pixels corresponding to the decimal part of the representative ratio value. Alternatively, the ratio is divided by a number n of 2 or more that results in a division result of 1 or less when the ratio is divided, and display image data for pixels (adjustment correction pixels) at a ratio corresponding to the division result is nth order. You may perform correction | amendment which makes it high.

  As described above, in the present embodiment, the correction is not performed based on the value itself obtained by analyzing the luminance unevenness for each line pixel group, but is grouped according to the luminance unevenness, and the representative ratio value set for each group is set. By performing the correction based on the correction amount, the data amount of the correction data describing the correction method can be reduced. As the number of stages for grouping increases, correction closer to the value of ci / B or dj / A analyzed for luminance unevenness can be given, but the size of the correction data also increases accordingly. On the other hand, if the number of stages to be grouped is small, the range of numerical values of ci / B and dj / A assigned to a certain unevenness intensity stage becomes large, and all the line pixel groups of unevenness included in this width have the same representative ratio value. Therefore, the correction data size can be reduced.

  Therefore, as a result of examination using an actual liquid crystal panel, it was confirmed that brightness unevenness can be corrected with less difficulty in being sufficiently visually recognized by grouping in 4 steps for both bright unevenness and dark unevenness. The correction data that describes the correction method only needs to describe to which unevenness intensity level each line pixel group belongs. Therefore, if there are 4 levels, this can be expressed with 2 bits. Therefore, the amount of data can be significantly reduced compared to converting the values of ci / B and dj / A into data.

  Furthermore, in the description of the method for detecting luminance unevenness, it has been described that the calculation of the moving average value shown in FIG. 3 preferably takes an average value in the range of 1 mm to 5 mm. It is also important to set the division to a small number of four stages. This will be described with reference to FIG.

  FIG. 8 is an example of the distribution of line-shaped luminance unevenness when a monochrome monotone display is performed on a certain liquid crystal panel. The position on the liquid crystal panel perpendicular to the line is the horizontal axis, and the luminance value of the line pixel group at that position. Is represented by a solid line. Further, the moving average value is indicated by a dotted line, and the entire luminance average is indicated by a one-dot chain line.

  However, if the moving average value is not taken as in the present embodiment and the luminance average value (dashed line) of the entire screen is set as the appropriate luminance value, it is analyzed as the difference between the appropriate luminance value and the actual luminance value. The unevenness intensity includes both local brightness unevenness that is easily visible and unevenness that is difficult to visually recognize over a relatively wide range, such as unevenness due to a backlight. In addition, gentle unevenness over a wide range is difficult to be seen by human eyes, but the position dependency of the luminance value is often large.

  In the example of FIG. 8, the luminance on the left side of the paper is generally dark, and the luminance tends to increase toward the right side of the paper. And, it can be seen that the brightness fluctuates finely. Here, the unevenness that is easily visible to the human naked eye is the latter, the upper and lower sides with finer brightness. That is, when the luminance unevenness intensity is detected using the average luminance value (dashed line) of the entire screen as the appropriate luminance value, the unevenness intensity value contributes to a wide range of unevenness that is difficult to be visually recognized. The contribution of unevenness becomes relatively small. Then, when grouping into appropriate stages by the method of FIG. 6, the following problem occurs.

  The method of FIG. 6 divides the luminance unevenness value of the line pixel group into stages with an appropriate width, and performs approximately the same correction on the line pixel group included in the brightness unevenness stage. Therefore, even if there is a difference in brightness between adjacent line pixel groups and they are visually recognized as line-like brightness unevenness, if they are all classified in the same brightness unevenness stage, the same correction is given. become. For this reason, the luminance difference between the line pixels can hardly be reduced, and the visually observed luminance unevenness remains. In order to prevent this and perform correction that cancels local unevenness, finer steps are required, and as a result, the data size of correction data for describing the correction method becomes large.

  On the other hand, in the present embodiment, the moving average value indicated by the dotted line in FIG. 8 is used as the appropriate luminance value, and the difference between this value and the actual luminance is the luminance unevenness intensity. That is, the feature is that the target luminance value is not set for the liquid crystal panel first, but the moving average value is defined as the appropriate luminance value based on the actually acquired luminance value. As shown in FIG. 8, the appropriate luminance value also has a distribution according to the position, and mainly reflects a gentle uneven distribution over a wide range. By comparing the appropriate luminance value with the actual luminance and taking a difference, it is possible to effectively detect local unevenness that is easily visible. Then, since unevenness that is easily visible can be detected effectively, even if the steps are divided as shown in FIG. 6 and approximate correction is given, the luminance distribution is gently as shown by the dotted line in FIG. As a result, local unevenness that is easily visible with a small amount of correction data can be effectively corrected and made inconspicuous.

  As described above, the width on the panel that takes the moving average is preferably 1 mm or more and 5 mm or less. For example, in the present embodiment in which the width on the panel that takes the moving average is calculated as 3 mm, even if the level division by luminance unevenness as shown in FIG. In addition, it is possible to effectively perform correction so that local unevenness is less visible.

  On the other hand, if the moving average width is less than 1 mm, local unevenness affects the distribution of the appropriate luminance value by the moving average indicated by the dotted line. There is a risk that unevenness will remain.

  Further, when the width on the panel for taking the moving average is larger than 5 mm, there is a possibility that the same problem as in the case where the whole average value is used as a reference, as described with reference to FIG. In other words, since a wide range of luminance is reflected in the appropriate luminance value and the distribution is over-leveled, the uneven intensity value detected as the difference between the appropriate luminance value and the actual luminance value is not easily recognized as unevenness. The luminance distribution is reflected, and the contribution of local unevenness that is easily visible is relatively reduced.

  For this reason, unless the stage division as shown in FIG. 6 is set finely, the visually recognized unevenness cannot be effectively corrected, leading to an increase in the amount of correction data. In other words, it is preferable to detect and correct visible unevenness at the same time, and not detect and correct unevenness that is difficult to visually recognize. From this point as well, a moving average of 1 mm to 5 mm in width is taken and this is appropriate. It is preferable to use a luminance value.

  In the above description, the example in which the representative ratio value of each luminance unevenness stage and the ratio of the adjustment correction pixel are set to the same value has been described. However, the present invention is not limited to this. For example, the ratio of the adjustment correction pixels may be set based on a value obtained by multiplying the representative ratio value by a predetermined correction coefficient.

  The correction coefficient may be set according to the gradation value of the display image data. For example, as described above, the luminance unevenness is easy to be visually recognized in a halftone, and is difficult to be visually recognized in the case of a display close to black and white. Therefore, the correction coefficient in the halftone may be set larger than the correction coefficient in the gradation close to black and white.

  When performing the above grouping for bright luminance unevenness, the correction data generation unit 16 determines the luminance value of each pixel (or each pixel group in which each pixel is grouped into a plurality of pixels) in the luminance data extracted from the imaging data. A luminance unevenness amount that is a difference from an appropriate luminance value of each pixel (or each pixel group) is calculated for each pixel (or each pixel group), and a variation value of the luminance unevenness amount (standard deviation of the luminance unevenness amount) And the calculated variation value of the luminance unevenness amount is divided by the difference B between the appropriate luminance value for the image data of the reference gradation value and the appropriate luminance value for the image data one gradation lower than the reference gradation value. The luminance unevenness regions are grouped based on the variation value of the luminance unevenness amount converted into gradation (standard deviation of the luminance unevenness amount converted into gradation) σ.

Specifically, the luminance value of each luminance unevenness region extracted from the imaging data obtained by imaging the display screen on which the image corresponding to the inspection image data of the reference gradation value is displayed, and the inspection image data The difference ci from the corresponding appropriate luminance value, the difference B between the appropriate luminance value for the image data of the reference gradation value and the appropriate luminance value for the image data one gradation lower than the reference gradation value, and the above-mentioned luminance converted in gradation Grouping is performed based on the unevenness variation value σ. For example, grouping is performed as follows.
Example of grouping (1)
Correction intensity 1 ci / B is 0.4σ or more and less than 0.8σ Correction intensity 2 ci / B is 0.8σ or more and less than 1.2σ Correction intensity 3 ci / B is 1.2σ or more and less than 1.6σ Correction intensity 4 ci / B is 1.6σ or more The stripe-like luminance unevenness of the display panel is greatly different for each display panel. That is, a display panel having a large degree of luminance unevenness (that is, a panel in which luminance unevenness is conspicuous) has a large σ, and a display panel having a small degree of luminance unevenness (that is, a panel in which the uneven luminance is difficult to recognize) has a small σ. Therefore, σ can also be used to determine the presence or absence of streaky luminance unevenness. That is, it can be determined that there is no streak-like luminance unevenness if σ is equal to or less than a predetermined value.

  By performing grouping (for example, grouping into about 5 types of groups) on the basis of σ which is the variation value of the luminance unevenness when the gradation is converted as described above, the panel and the luminance unevenness having a large luminance unevenness are obtained. Both small panels can be grouped well.

  FIG. 6 shows an example of grouping display panels in which σ, which is the variation value of the luminance unevenness when converted into gradations as calculated above, is 0.25. Since the region of the correction intensity 1 is 0.4σ or more and less than 0.8σ, the luminance unevenness region in which the ratio is 0.10 or more and less than 0.20 is classified as the correction intensity 1. Similarly, the luminance unevenness region where the ratio is 0.20 or more and less than 0.30 is the correction strength 2, the luminance unevenness region where the ratio is 0.30 or more and less than 0.40 is the correction strength 3, and the ratio is 0.40 or more. Luminance unevenness areas are classified into correction intensity 4.

  For a luminance unevenness region having a correction intensity of 1, the representative ratio value is set to 0.15 which is the median value of the group, and correction is performed to reduce the gradation by one gradation at a ratio of 3 pixels to 20 pixels. Good. However, 1/7, which is a value close to the median value of 0.15 and represented by a relatively small integer ratio, may be used as the representative ratio value. Correction may be performed to lower the value by one gradation. For example, at the position corresponding to ck shown in FIG. 6, since the value of ck / B is 0.12, it is classified as correction strength 1, and the gradation value is 1 gradation at a ratio of 1 pixel to 7 pixels. Make corrections to lower.

  Similarly, with respect to the correction strengths 2, 3, and 4, the representative ratio values are set to 0.25, 0.35, and 0.45, which are the median values of the group, and this ratio, that is, 20 pixels is 5 pixels and 7 pixels. , Correction may be performed to lower one gradation at a rate of 9 pixels. Alternatively, 1/4, 1/3, and 1/2, which are approximate values and represented by a relatively small integer ratio, are representative ratio values, each having 1 pixel for 4 pixels, 1 pixel for 3 pixels, Correction may be performed to lower one gradation at a rate of one pixel per two pixels. For example, the position corresponding to cl has a cl / B value of 0.29 and is classified as correction intensity 2. Therefore, based on the representative ratio value, the gradation value is set to one gradation at a ratio of one pixel to three pixels. Make corrections to lower. The position corresponding to cm has a cm / B value of 0.42 and is classified as correction intensity 4. Therefore, based on the representative ratio value, correction is performed to lower the gradation value by one gradation at a ratio of one pixel to two pixels. I do. At the position corresponding to cn, since the value of cn / B is 0.37, it is classified as correction intensity 3, and correction is performed to reduce the gradation value by one gradation at a ratio of one pixel to three pixels.

  As described above, for the line pixel group having a ci / B value included in a certain range, the pixels are corrected at the same ratio, and pixels having an approximate ratio different from the actual ci / B value. Will be corrected. However, as described above, since the unevenness detection method using the moving average method is employed, unevenness that is easily visible can be extracted effectively. Therefore, the unevenness can be made inconspicuous even by such an approximate method.

  As described above, by grouping the luminance unevenness regions, the correction data describing the correction method and instructing the correction method to the correction circuit in the liquid crystal can be reduced in capacity. This is because the same correction data can be applied to the luminance unevenness regions of the same group, so that the types of correction data can be reduced. Accordingly, the capacity of correction data to be stored in the correction data storage unit 31 provided in the drive control unit 22 of the display device 20 can be reduced.

  Thus, the correction data includes, for example, a source line (correction area position information) corresponding to luminance unevenness and group information about the source line.

  In the above description, the correction data generation unit 16 corrects only the pixels in the detected luminance unevenness region. However, the present invention is not limited to this. A pixel in a region including a pixel or a range of about several millimeters) may be a correction target. That is, the luminance unevenness region may be used as the correction region, and the region including the luminance unevenness region and its surrounding region may be used as the correction region. As described above, by including the peripheral region in the correction region, it is possible to make the luminance unevenness region less visible by blurring the outline of the luminance unevenness region.

  Further, it is not always necessary to correct all the detected luminance unevenness areas, and only a part of the detected brightness unevenness areas may be corrected. For example, it is possible to extract and correct only the luminance unevenness region that is easily visually recognized according to the size of the luminance unevenness region or the degree of deviation from the appropriate luminance value.

  Further, the correction data generation unit 16 may calculate the correction data for each of R (Red), G (Green), and B (Blue) sub-pixels. , G, and B, correction data for one color (for example, G) may be generated and shared for other colors. In many cases, streaky luminance unevenness continuously occurs within a predetermined range, so that correction data generated for one color of R, G, and B is applied to subpixels of other colors on both sides. However, the degree of image quality is almost the same as in the case where correction data is individually generated for each of R, G, and B colors. In addition, by using common correction data for each color of R, G, and B, a correction for storing correction data provided in the display device 20 to be described later, compared to a case where individual correction data is generated for each color. The storage capacity required for the data storage unit 31 can be reduced.

  Here, the description method of the correction data will be described.

  As described above, in this embodiment, correction is not performed using the unevenness intensity value itself, but is classified into several stages according to unevenness intensity, and the same correction method is used for uneven areas belonging to that stage. It suffices if information indicating which correction intensity is to be given to which uneven area is informationized. If the correction intensity is 4 levels, this can be expressed by 2 bits. For example, the correction strength 1 can be described as [00], the correction strength 2 as [01], the correction strength 3 as [10], and the correction strength 4 as [11].

  Therefore, using this, for example, the following description method can be taken. According to the pixel position on the panel in order from one end on the panel, (a) whether correction is performed (correction necessity information), (b) dark unevenness correction or bright unevenness correction (correction gradation information) And (c) which correction intensity group is described. When only one of dark unevenness correction and bright unevenness correction is performed, the information related to (b) can be omitted.

  For example, (a) whether or not correction is performed is defined as “no correction” = [0] and “correction” = [1]. When this bit is [0], the next bit is regarded as an information bit indicating whether or not (a) correction is performed for the next line pixel group. In the case of [1], (b) dark unevenness correction or bright unevenness correction is designated by the next bit. Here, it is defined that “dark unevenness correction” = [0] and bright unevenness correction = [1]. Further, in the subsequent 2 bits, (c) which correction intensity group is designated, and the subsequent bits are regarded as information bits indicating whether or not (a) correction of the next line pixel group is performed. The flow of the above correction data description is as shown in FIG.

  Next, consider the case where unevenness is distributed as shown in FIG. 9 according to this data description method. FIG. 9 is an explanatory diagram for explaining a correction information generation method.

  First, since the first c1 is not corrected, the first bit of the correction data is set to [0]. The next bit is information on whether or not c2 is corrected, and the third bit is also set to [0]. Further, since c3 is not corrected, the third bit is also set to [0]. The subsequent c4 corrects bright unevenness and has a correction intensity of 1. Therefore, [1] (with correction), [1] (correction of bright unevenness), and [00] (correction intensity 1) are obtained. 1100] is represented by 4 bits. The subsequent line pixel group c5 is a correction of bright unevenness and a correction strength of 2, and is represented by 4 bits [1101] in the same manner as described above. The subsequent c6 and c7 are bright unevenness corrections, which are correction intensity 4 and correction intensity 3, respectively, and are expressed by 4 bits [1111] [1110]. Since c8 is not corrected, it is represented by only one bit [0]. The subsequent c9, c10, and c11 are corrections for dark unevenness, which are correction intensity 2, correction intensity 2, and correction intensity 1, respectively, and thus are described as [1001] [1001] [1000]. As a result, the correction method from c1 to c11 is described as [0001100110111111110001001100111000] and 32 bits.

  In the above method, since the line pixel group that is not corrected can be expressed by 1 bit and the line pixel group that is corrected is expressed by 4 bits, for example, when the number of line pixel groups is 360 and half of them are 180 line pixel groups, A description with a small data amount of 900 bits is possible. The correction data is stored in a correction data storage unit 31 of the display device 20 described later.

  In this example, the correction strengths 1, 2, 3, and 4 correspond to correction at a ratio of 1 pixel for 7 pixels, 1 pixel for 4 pixels, 1 pixel for 3 pixels, and 1 pixel for 2 pixels, respectively. is doing. A table indicating the correspondence relationship between the correction intensity and the ratio is required. This table may be stored in another area of the correction data storage unit 31 or separately in the drive circuit of the display device 20. A ROM may be provided to store information therein. In particular, as in this example, if the method of dividing the correction stage is the same for bright unevenness and dark unevenness and the same representative ratio value is given to the same correction intensity (for example, the correction intensity 2 is 4 for both bright unevenness and dark unevenness). It is possible to reduce the amount of information related to the correction ratio).

  Further, as a description method of correction data for each line pixel group, the following method can be adopted, and the data amount can be further reduced.

  That is, in the example of FIG. 9, when bright unevenness continues like c4 to c7, or when dark unevenness continues like c9 to c11, (b) dark unevenness correction or bright unevenness correction, Is designated only in the first line pixel group (c4 and c9), and the subsequent line pixel group is referred to this designation. When the correction method of FIG. 9 is described by this method, c1 to c3 are [0] [0] [0] as in the above example, and c4 is also [1100] as in the above example, but c5, c6, and c7 are c4. By referring to [1] of the second bit, only the information of (a) and (c) may be described, that is, [101] [111] [110] is described. The information of the second bit of c4 is stored and applied to the subsequent line pixel group until a line pixel group in which (a) is [0] (no correction) appears. At the same time, 2 bits following (a) information become (c) information ((b) description of information is omitted). Subsequently, since c8 is uncorrected [0], information [1] of the second bit of c4 is reset here. The subsequent bits are regarded as information on whether or not to perform the correction of c9 (a), and in the example of FIG. 9, there is correction and is [1]. The succeeding 1 bit is (b) dark unevenness correction or bright unevenness correction. The dark unevenness is [0], and the subsequent 2 bits describe the correction strength (c) (the correction strength is 2 [01]. And the correction information of c9 is described as [1001]. Since c10 and c11 continue to be corrected for dark unevenness, the information (b) of c9 is also assigned to them, and only the information (a) and (c) need to be described. 2), [100] (correction intensity 1). (A) Until the information is [0], that is, an uncorrected line pixel group appears, the correction method for each line pixel group is described in units of 3 bits.

  The flow of the above data description is as shown in FIG. FIG. 11 is a flowchart for explaining a method of describing as correction data.

  According to this method, the correction data from c1 to c11 in FIG. 9 can be described by [0001100101111110001001101100] and 27 bits, and FIG. 10 is a flowchart illustrating the method of describing the correction data. The amount of data can be reduced as compared with the above method. In this method, when the line pixel groups with correction are continuous, information (b) information (dark unevenness correction or bright unevenness correction) is described only in the first line pixel group, and the remaining line pixel groups are included in the remaining line pixel groups. By applying the same information (b), the description of (b) information is omitted, and the data amount is reduced. For this reason, as long as the line pixel groups with correction are continuous, the same information (b) is obtained. Therefore, when the line pixel group for correcting dark unevenness and the line pixel group for correcting bright unevenness are adjacent to each other. Cannot write correction data. For this reason, when bright unevenness and dark unevenness are close to each other, an uncorrected line pixel group is always inserted into the boundary portion, and (b) information is reset here.

  In the example of FIG. 9, since there is uncorrected c8 between the bright unevenness c4 to c7 and the dark unevenness c9 to c11, the data description method of FIG. 11 is possible. However, as a result of the unevenness intensity analysis, when c8 / B is included between 0.10 and 0.20 and is classified as correction intensity 1, bright unevenness correction is performed in c8 to c9. Correction of dark unevenness is adjacent, and data description cannot be performed by the method of FIG. In such a case, c8 and c9 are compared, and the lower unevenness intensity may be changed to no correction. Actually, the unevenness is easily recognized mainly in the vicinity of the peak position of luminance unevenness (c6 and c10 in FIG. 9). Even if the above-described change is made at the boundary between the brightness and darkness, the unevenness correction is performed. There is almost no effect on the effect. Therefore, even in such a case, the method of FIG. 11 is possible.

  Further, the following method can be adopted as a data description method.

  This method is described according to the method of FIGS. 10 to 11 when (a) is [1] (with correction), but when (a) is [0] (without correction), the following several bits are used. (D) Describes how many uncorrected line pixel groups continue (uncorrected information). For example, FIG. 12, which is a flowchart for explaining a method of describing correction data, applies the above method to FIG. 11 and (d) expresses information in 4 bits (example here) Is a binary representation of a value obtained by subtracting 1 from the continuous number of uncorrected line pixel groups, and is expressed up to 16).

  When describing the correction of FIG. 9 according to the above method, the information of c1 to c3 is indicated by an uncorrected number after correction [0], and in this example, three uncorrected line pixel groups follow. Therefore, since it is expressed as [0010], it becomes [00010] after all. Further, c8 is [0] [0000] because the uncorrected line pixel group is not continuous. As a result, when the method of FIG. 11 is changed to the present method, the description of c1 to c11 is [0001011001011111110000001001101100], which is 33 bits.

The method of FIG. 12 is a very effective data reduction method particularly when there are many consecutive uncorrected line pixel groups on the display screen. For example, consider a case where grouping by correction strength is performed as follows.
Example of grouping (2)
Correction intensity 1 ci / B to di / A is 1.0σ or more and less than 1.4σ Correction intensity 2 ci / B to di / A is 1.4σ or more and less than 1.8σ Correction intensity 3 ci / B to di / A is 1 .8σ or more and less than 2.2σ correction strength 4 ci / B to di / A is 2.2σ or more The grouping is set at a higher value than the grouping example (1). Any unevenness in which ci / B to di / A is less than 1.0σ is not corrected and is not corrected. For this reason, in the grouping example (2), the number of line pixel groups included in the correction intensities 1 to 4 is reduced because the step division is set at a higher value than in the grouping example (1). Since the number of uncorrected line pixel groups increases, the correction data capacity tends to decrease.

However, in particular, when the stage division is set to a high value as in this grouping example (2), the frequency of the uncorrected line pixel group is increased, and the data reduction effect by the method of FIG. 12 is effective. It will be remarkable. Actually, an example of analyzing unevenness and creating unevenness correction data with regard to four liquid crystal panels (panels 1 to 4) having 360 source lines by regarding the source lines as line pixel groups is as follows. Show.
In the case of panel 1, uncorrected line = 267, corrected line = 93
Correction Data Amount Case of Method in FIG. 10 = 639 bits, Method in FIG. 11 = 575 bits, Method in FIG. 12 = 488 Bit Panel 2 Uncorrected Line = 311, Corrected Line = 49
Correction Data Amount In the case of FIG. 10 method = 507 bits, FIG. 11 method = 483 bits, FIG. 12 method = 347 bit Panel 3 Uncorrected line = 299, Corrected line = 61
Correction Data Amount Case of Method in FIG. 10 = 543 Bit, Method in FIG. 11 = 510 Bit, Method in FIG. 12 = 401 Bit Panel 4 Uncorrected Line = 322, Corrected Line = 38
Correction Data Amount As shown in FIG. 10, the method of FIG. 10 = 474 bits, the method of FIG. 11 = 451 bits, the method of FIG. 12 = 269 bits or more, and the method of FIG. It has become.

  In this way, by describing the correction method with a small data capacity, a free area in an existing memory provided in the display device can be used as the correction data storage unit 31.

  FIG. 13 is a block diagram illustrating a configuration of the drive control unit 22 provided in the display device 20. As shown in this figure, the drive control unit 22 includes a correction data storage unit 31, a decoding unit 32, a spatial dispersion processing unit 33, a time dispersion processing unit 34, an addition processing unit 35, a first latch unit 36, and a second latch unit. 37, and a D / A converter 38. The spatial dispersion processing unit 33, the time dispersion processing unit 34, and the addition processing unit 35 form an image data correction unit.

  The correction data storage unit 31 is a non-volatile memory that stores correction data input from the correction data generation device 10 when the display device 20 is inspected. In the present embodiment, the correction data described by the correction data creation device 10 is stored in the correction data storage unit 31.

  When the display unit 20 displays an image corresponding to the display image data on the display panel 21, the decoding unit 32 reads the correction data stored in the correction data storage unit 31, decodes the correction data, and performs gradation The correction information is output to the spatial dispersion processing unit 33.

  The spatial dispersion processing unit 33 sets the position of the adjustment correction pixel in each source line corresponding to the luminance unevenness region based on the gradation correction information input from the decoding unit 32, and the gradation correction information indicating the setting result Is output to the time dispersion processing unit 34. Specifically, it is determined how many pixels from the end of the source line are to be adjusted and corrected (offset value), and the pixels and pixels at predetermined intervals from the pixels are set as adjusted correction pixels. .

  In addition, when luminance unevenness occurs across a plurality of adjacent source lines, the positions of the adjustment correction pixels in the source lines in the extension direction of the source lines in each source line are different between adjacent source lines and distributed. Alternatively, the position of each adjustment correction pixel may be set. FIG. 14 is an explanatory diagram showing an example of the position of the adjustment correction pixel in this case.

  Based on the correction information input from the spatial dispersion processing unit 33, the time dispersion processing unit 34 sets the position of the adjustment correction pixel in each source line so as to change every predetermined period (for example, every frame), Correction information indicating the setting result is output to the addition processing unit 35. FIG. 1 is an explanatory diagram illustrating an example of the position of the adjustment correction pixel set by the time dispersion processing unit 34. In the example shown in this figure, the time distribution processing unit 34 keeps the ratio of the adjustment correction pixels (the pitch between the adjustment correction pixels) constant, and sets the position (offset value) of the adjustment correction pixels for each frame of the source line. The drawing direction is changed.

  Note that the order of the spatial dispersion processing unit 33 and the time dispersion processing unit 34 may be reversed. In other words, the gradation correction information may be input from the decoding unit 32 to the time dispersion processing unit 34, and the gradation correction information may be input from the time dispersion processing unit 34 to the spatial dispersion processing unit 33.

  The addition processing unit 35 corrects the display image data by adding a correction value based on the gradation correction information input from the time dispersion processing unit 34 to the display image data input to the display device 20. The subsequent display image data is output to the first latch unit 36. That is, among the pixels in the display image data, the gradation value of the display image data is changed by at least one gradation with respect to the adjustment correction pixel indicated by the gradation correction information (at least according to the gradation correction information). A correction process is performed to increase or decrease one gradation.

  Specifically, in the luminance unevenness region where the ratio is 1 or less, the gradation value of the adjustment correction pixel is changed by one gradation, while the other pixels are not corrected. For the luminance unevenness region where the ratio exceeds 1, the gradation value of each pixel is changed by the gradation value corresponding to the integer part of the ratio, and the gradation value of the adjustment correction pixel is further increased by one gradation. Change. Alternatively, in the luminance unevenness region where the ratio exceeds 1, the gradation value of the adjustment correction pixel may be changed by the gradation value corresponding to the value of n, but the other pixels may not be corrected.

  The first latch unit 36 sequentially samples the display image data after correction output from the addition processing unit 35 in synchronization with a sampling pulse generated based on the clock signal, for one line (one gate line). Latch image data. The second latch unit 37 re-latches the image data for one line latched by the first latch unit 36.

  The D / A conversion unit (digital / analog conversion unit) 38 converts the image data for one line latched by the second latch unit 37 into an analog signal and outputs it to each source line of the display panel 21 at a predetermined timing. To do.

  The display panel 21 includes a large number of gate lines (scanning signal lines) and a large number of source lines (data signal lines), and a pixel is provided in each of the matrix regions defined by the gate lines and the source lines. (Both not shown).

  Each pixel is composed of a switching transistor and a pixel capacitor, and the pixel capacitor is composed of a liquid crystal capacitor and an auxiliary capacitor that is added as necessary (none is shown). The switching transistor has a gate connected to the gate line, a source connected to the source line, and a drain connected to one electrode of the pixel capacitor. Note that the other electrode of the pixel capacitor is connected to a common electrode line common to all pixels.

  As a result, when a gate line is selected by a gate driver (not shown), the switching transistor of each pixel connected to the selected gate line becomes conductive, and in synchronization therewith, the D / The voltage applied from the A converter 38 to each source line is applied to the corresponding pixel capacitor.

  Note that while the selection period of the gate line ends and the switching transistor is shut off, the pixel capacitor continues to hold the voltage at the time of the shut-off. Since the transmittance or reflectance of the liquid crystal changes depending on the voltage applied to the liquid crystal capacitor, the display state of the pixel is changed to image data by selecting a gate line and applying a voltage corresponding to the image data to the source line. It can be changed together.

  As described above, the correction data creating apparatus 10 according to the present embodiment displays an image corresponding to the inspection image data of the same gradation on all the pixels of the display panel 21 to capture the display screen, and from the captured data. Luminance data is extracted, and streaky luminance unevenness is extracted from the extracted luminance data. Then, correction data including position information of each luminance unevenness region and group information obtained by grouping each luminance unevenness region based on a variation value of the luminance unevenness amount of each luminance unevenness region is generated and provided in the display device 20. Stored in the correction data storage unit 31.

  When the display device 20 displays an image corresponding to the display image data on the display panel 21, the display device 20 is based on the position information and group information of each luminance unevenness region in the correction data stored in the correction data storage unit 31. Correct brightness unevenness.

  As described above, since the luminance unevenness areas are grouped, the capacity of the correction data can be reduced. Therefore, even when the capacity of the correction data storage unit 31 is small, the correction data can be appropriately stored.

  FIG. 15 shows luminance data obtained from imaging data obtained by imaging the display panel 21 in a state where an image corresponding to inspection image data that has not been subjected to correction processing is displayed, and inspection image data that has undergone correction processing. It is a graph which shows the luminance data of the luminance data obtained from the imaging data which imaged the display panel 21 on which the corresponding image was displayed. The horizontal axis indicates the position of each line pixel group, and the vertical axis indicates the luminance value of each line pixel group (the average value of the luminance values of the pixels belonging to each line pixel group). As is clear from these graphs, the correction method according to the present embodiment can correct the image data so that stripe-like luminance unevenness is not visually recognized.

  In this embodiment, the position of the adjustment correction pixel is changed for each frame. That is, the positions of the adjustment correction pixels are dispersed spatially and temporally within the luminance unevenness region.

  Thereby, it can prevent more appropriately that brightness nonuniformity is visually recognized.

  In the present embodiment, the correction data storage unit 31 provided in the display device 20 stores information indicating the position of the luminance unevenness region and the group information, and the spatial dispersion processing unit 33 provided in the display device 20. When the image according to the display image data is displayed by the time dispersion processing unit 34, the position of the adjustment correction pixel in the luminance unevenness region is determined to be spatially and temporally dispersed. In particular, by using the correction data description method described above, the data size of the correction data can be reduced and the storage capacity required for the correction data storage unit 31 can be reduced.

  In the present embodiment, the case of correcting the stripe-shaped luminance unevenness parallel to the extending direction of the source line has been described. However, the present invention is not limited to this, and the stripe-shaped uneven luminance unevenness parallel to the extending direction of the gate line is corrected. You can also. In this case, for example, the average value of the luminance values for the line pixel group corresponding to the extending direction of each gate line is detected based on the luminance data extracted from the imaging data, and the detection result is perpendicular to the line pixel group. It is only necessary to perform moving average processing for the direction and detect luminance unevenness based on these processing results. Further, based on the detection result of luminance unevenness, pixels at predetermined intervals in the gate line corresponding to the luminance unevenness region are selected as adjustment correction pixels, and the gradation value of the selected adjustment correction pixel is changed by at least one gradation. The image data may be corrected.

  In the present embodiment, when calculating the deviation of the luminance value with respect to the appropriate luminance value in each luminance unevenness region, the moving value of the luminance value of the line pixel group is regarded as the appropriate luminance value, and the deviation of the above luminance value is calculated. To do. As a result, even if the appropriate luminance value varies depending on the position on the display screen due to, for example, the luminance distribution of the irradiation light from the backlight, the degree of deviation of the luminance value with respect to the appropriate luminance value in each luminance unevenness region is reduced. It can be calculated easily and appropriately. For example, when an appropriate luminance value corresponding to a position on the display screen is known in advance, a deviation of the luminance value in each luminance unevenness region may be calculated based on the appropriate luminance value.

[Embodiment 2]
Another embodiment of the present invention will be described. For convenience of explanation, members having the same functions as those described in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and description thereof is omitted.

  In the first embodiment, the configuration for correcting streaky unevenness has been described. However, in the present embodiment, a configuration example in the case of correcting local spotted unevenness (spotted unevenness) will be described.

  FIG. 16 is a block diagram showing the configuration of the correction data creation device 10b according to the present embodiment. As shown in this figure, the correction data creation device 10b is a moving average processing instead of the moving average processing unit 14, the luminance unevenness detection unit 15, and the correction data generation unit 16 of the correction data creation device in the first embodiment. Unit 14b, luminance unevenness detection unit 15b, and correction data generation unit 16b. The functions of the display data generation unit 11, the imaging unit 12, and the luminance data extraction unit 13 are substantially the same as those in the first embodiment.

  In the moving average processing unit 14b, the display data generating unit 11 displays an image corresponding to image data of the same gradation (reference gradation value, for example, gradation value 10) over the entire area of the display panel 21, and the imaging unit 12 With respect to the luminance data extracted by the luminance data extraction unit 13 from the image data obtained by capturing the image, the luminance value of each pixel is the average value of the luminance values of the pixels included in a block having a predetermined size centered on each pixel. The moving average processing to replace with is performed. Hereinafter, the luminance value of each pixel after the moving averaging process is referred to as a moving average value.

  Note that the predetermined size is sufficiently wider than the width of the spot-like luminance unevenness region, and the difference in the luminance value of the light emitted from the backlight at each position within the predetermined size is the appropriate luminance value of the luminance value in the luminance unevenness region. It is preferable to set a range that is sufficiently small with respect to deviation from the value. Specifically, in the case of a display panel of about several hundred pixels × several hundred pixels provided in a mobile device such as a mobile phone, it is preferably set in a range of 2 mm × 2 mm to 10 mm × 10 mm. In this embodiment, the display panel 21 of 360 pixels × 480 pixels is used, and the above range is 5 mm × 5 mm. Note that the length in the vertical direction and the length in the horizontal direction in the predetermined size are not necessarily the same.

  The luminance unevenness detection unit 15b calculates the difference (luminance unevenness amount) between the luminance value of each pixel extracted by the luminance data extraction unit 13 and the moving average value for each pixel, and the absolute value of this difference is a predetermined threshold value. A region where a predetermined number or more of the above pixels are continuous is detected as spot-like luminance unevenness.

  Further, the predetermined number may be set as appropriate according to the size and application of the display device so as to prevent uneven brightness from being visually recognized.

  The correction data generation unit 16b generates correction information for making it difficult to visually recognize the spot-like luminance unevenness based on the detection result of the luminance unevenness detection unit 15b, and uses this as correction data in accordance with a predetermined data description method. It outputs to the drive control part 22b with which the apparatus 20b is equipped.

  Here, a method for correcting spotted unevenness in the present embodiment will be described. The spot-like unevenness assumed in the present embodiment is a bright spot-like unevenness that appears brighter than the surroundings and a dark spot-like unevenness that appears darker than the surroundings when a uniform image is displayed on the display panel.

  FIG. 17 shows a conceptual diagram of a method for correcting spotted unevenness in the present embodiment.

  In this embodiment, as a method for correcting spotted unevenness, as shown in FIG. 17, only four types of correction patterns are used for each of bright spotted unevenness and dark spotted unevenness, and a spot where spotted unevenness occurs. The method of making the spotted unevenness inconspicuous by applying to the above is adopted. In the present embodiment, four types of correction patterns are used for correction of spotted unevenness, but the present invention is not limited to this. The more types of correction patterns, the better the unevenness correction, but the storage capacity stored in the correction pattern storage unit 39 (see FIG. 18 described later) provided in the display device 20b increases. For this reason, the type of the correction pattern may be appropriately adjusted according to the capacity of the correction pattern storage unit 39.

  Since the luminance unevenness amount of the spot-like unevenness is normally 1 gradation or less when converted into a gradation value, the correction pattern is a pixel (adjustment correction pixel) for correcting plus 1 gradation or minus 1 gradation. It is necessary to dispose spatially. Here, the luminance unevenness amount is a difference between the luminance value of each pixel extracted by the luminance data extraction unit 13 and the moving average value for each pixel.

  The so-called dither method is used for correction of one gradation or less. The dither method is an image processing technique for expressing more gradations in a pseudo manner with fewer gradations. In the spotted unevenness correction method according to the present embodiment, in order to correct unevenness of one gradation or less, one gradation is divided into 16 steps, and correction of one gradation or less is performed in units of 1/16 gradation. . Specifically, a dither matrix in which values of 1 to 16 are assigned to each 4 × 4 square as shown in FIG. 19 is used. For example, when it is desired to lower the gradation of 5/16 gradations, correction of minus one gradation may be performed on pixels corresponding to 1 to 5 of the dither matrix shown in FIG.

  Note that the pixels of the color display panel include R (red), G (green), and B (blue). In this embodiment, as shown in FIG. 19, a dither matrix is used for each of R, G, and B colors. It is different. Accordingly, the correction pixels can be spatially sparsely arranged, and unevenness correction can be performed more satisfactorily.

  As described above, in this embodiment, correction of 1 gradation or less is performed in units of 1/16 gradation using a 4 × 4 dither matrix. Therefore, the basic unit of correction is an area of 4 pixels × 4 pixels.

  In the present embodiment, a basic correction pattern of 4 pixels × 4 pixels for correcting spotted unevenness is generated using the 4 × 4 dither matrix described above. FIG. 20 shows a basic correction pattern of 4 pixels × 4 pixels created using the dither matrix. In FIG. 20, pixels other than white (pixels indicated by diagonal lines) are adjustment correction pixels that increase or decrease one gradation. The dither matrix may be stored in the drive control unit 22b of the display device 20, and the drive control unit 22b may calculate the basic correction pattern based on the dither matrix. The pattern may be stored in the correction pattern storage unit 39 provided in the drive control unit 22b.

  In this embodiment, four basic correction patterns are stored in the correction pattern storage unit (basic correction pattern storage unit) 39 for each of bright spot-like unevenness and dark spot-like unevenness, and the spatial dispersion processing unit 33b. The basic correction pattern corresponding to the variation value of the luminance unevenness amount of each luminance unevenness region (standard deviation of the luminance unevenness amount) is selected to determine the adjustment correction pixel.

  For example, the variation value of the luminance unevenness (the luminance unevenness amount) that is the difference between the luminance value of each pixel extracted by the luminance data extraction unit 13 and the moving average value (appropriate luminance value) for each pixel of a certain display panel. When the standard deviation is 3 and the difference A between the appropriate luminance value for the image data of the reference gradation value and the appropriate luminance value for the image data that is one gradation higher than the reference gradation value is 10, the amount of luminance unevenness converted to gradation The variation value σ is 0.3.

  Using this value, a basic correction pattern of 4 pixels × 4 pixels corresponding to 0.5σ, 1.0σ, 1.5σ, and 2.0σ is selected in order from weak correction to dark spotted unevenness. I will do it. That is, in the case of FIG. 20, the basic correction pattern of the above four 4 pixels × 4 pixels is the basic 02 and gradation 0.30 (1...) Closest to the gradation 0.15 (0.5 × 0.3). Basic 05 closest to 0 × 0.3), Basic 07 closest to gradation 0.45 (1.5 × 0.3), and one to gradation 0.60 (2.0 × 0.3) The closest base 10 is selected. In the area where the selected basic correction pattern is applied, correction is performed so that the gradation value of the pixel corresponding to the pixel other than white in the basic correction pattern is increased by one gradation.

  In the following description, a basic correction pattern of 4 pixels × 4 pixels corresponding to 0.5σ corresponds to an A1 pattern, a basic correction pattern of 4 pixels × 4 pixels corresponding to 1.0σ corresponds to a B1 pattern, and 1.5σ. A basic correction pattern of 4 pixels × 4 pixels is a C1 pattern, and a basic correction pattern of 4 pixels × 4 pixels corresponding to 2.0σ is a D1 pattern. Here, the case where the A1 pattern, the B1 pattern, the C1 pattern, and the D1 pattern correspond to 0.5σ, 1.0σ, 1.5σ, and 2.0σ, respectively, will be mainly described, but not limited thereto. The basic correction pattern can be appropriately adjusted according to the degree of luminance unevenness. For example, the patterns corresponding to 1.2σ, 1.6σ, 2.0σ, and 2.4σ may be used as the A1 pattern, B1 pattern, C1 pattern, and D1 pattern.

  Four basic correction patterns of 4 pixels × 4 pixels for bright spotted unevenness can be obtained by a method similar to the method for selecting three basic correction patterns corresponding to dark spotted unevenness. Accordingly, four basic correction patterns are selected from the 16 basic correction patterns shown in FIG. 20 in accordance with the variation value of the brightness unevenness amount of bright spotted unevenness, and the area to which the selected basic correction pattern is applied. Then, correction is performed so that the gradation value of the pixel corresponding to the pixel other than white in the basic correction pattern is lowered by one gradation. In the following description, the four basic correction patterns corresponding to bright spotted unevenness are referred to as an A2 pattern, a B2 pattern, a C2 pattern, and a D2 pattern, respectively.

  In the present embodiment, the correction area corresponding to the dark spot-like unevenness is corrected using a combination of the four basic correction patterns A1 to D1 described above, and the correction area corresponding to the bright spot-like unevenness. Is corrected using a combination of the above-described A2 pattern to D2 pattern.

  Specifically, the spot-like unevenness generally has the largest amount of luminance unevenness at the center thereof, and the amount of unevenness in brightness decreases with increasing distance from the center. Therefore, in the present embodiment, the four basic correction patterns are combined so that the correction intensity becomes stronger as it is closer to the center of the correction area. FIG. 21 shows an example of a correction pattern obtained by combining four basic correction patterns. Here, A in FIG. 21 corresponds to the A1 pattern and A2 pattern, B corresponds to the B1 pattern and B2 pattern, C corresponds to the C1 pattern and C2 pattern, and D corresponds to the D1 pattern and D2 pattern. That is, A, B, C, and D in FIG. 21 each have a size of 4 pixels × 4 pixels. Further, O in FIG. 21 always corresponds to the basic 00 in FIG. That is, correction is not performed for the pixels corresponding to O in FIG. For example, any one of the patterns 1 to 4 shown in FIG. 21 may be selected according to the size of the correction region corresponding to the spotted unevenness. The example shown in FIG. 21 is an example of a correction pattern, and the method of combining basic correction patterns is not limited to this, and can be adjusted as appropriate according to the size and shape of spotted unevenness.

  In this way, a table in which the size (or size and shape) of the correction pattern for correcting spotted unevenness is associated with the arrangement method of the four basic correction patterns is prepared. Four basic correction patterns are appropriately selected according to the degree of luminance unevenness (variation value of luminance unevenness in spotted unevenness), and the size (or size and shape) of the correction area corresponding to the spotted unevenness is selected. By selecting a corresponding correction pattern, it is possible to appropriately correct the spotted unevenness.

  Further, according to the above method, it is possible to correct spotted unevenness using a small number of correction patterns and basic correction patterns, so that the storage capacity of the correction data storage unit 31b and the correction pattern storage unit 39 is very large. Can be reduced.

  In the present embodiment, the luminance unevenness detection unit 15b selects a correction pattern having a size closest to the size of the correction region corresponding to the actual luminance unevenness region of the display panel from the correction patterns shown in FIG. The position to which the correction pattern is applied (or the position of the correction area), the pattern number of the correction pattern, and information indicating whether it is dark spot-like unevenness or bright spot-like unevenness is sent to the correction data generating unit 16b.

  The correction data generation unit 16b selects a basic correction pattern corresponding to A, B, C, and D in the correction pattern for each of bright spot-like unevenness and dark spot-like unevenness.

  In this manner, the correction data generation unit 16b applies the correction pattern sent from the luminance unevenness detection unit 15b (or the position of each correction area), the pattern number of the correction pattern, and dark spot light unevenness or bright spot shape. In addition to information indicating unevenness, correction data indicating the basic correction patterns corresponding to A, B, C, and D in the correction pattern for each of bright spot-like unevenness and dark spot-like unevenness is generated.

  Specifically, in the case of a display device of 360 pixels × 480 pixels, a natural number of 360 or less can be described by 9 bits, and a natural number of 480 or less can also be described by 9 bits. Therefore, (a) position information can be described by a total of 18 bits, The position can be specified with pixel unit accuracy. As to what correction is to be given at that position, first, (b) whether to apply bright unevenness correction or dark unevenness correction can be described with one bit (either bright unevenness correction or dark unevenness correction). If you only want to do this, you can omit this bit). Furthermore, (c) it is only necessary to specify which of the four basic correction patterns is to be selected, so this can be described with 2 bits. As a result, when specifying one basic correction pattern arrangement, it can be described with a total of 21 bits. If the basic pattern of spot unevenness is arranged at 100 locations on the display screen, this can be described with 2100 bits.

  Alternatively, the bright unevenness correction and the dark unevenness correction may be expressed by the number thereof. In this case, the bit of whether to provide the bright unevenness correction or the dark unevenness correction is omitted. Is possible.

  For example, consider a case where there are 70 bright unevenness corrections and 30 dark unevenness corrections. The number of corrections is expressed by 7 bits each (the number of bits to be expressed can be appropriately determined for each display device model), and therefore can be described by 14 bits in total. Since (a) the position information is described in 18 bits, and (c) which one of the four basic correction patterns is selected is described in 2 bits, the basic correction pattern is arranged in 20 bits per location, It can be specified in pixel units. Therefore, since there are 70 bright unevenness corrections, a total of 20 × 70 = 1400 bits is described. Since there are 30 dark unevenness corrections as dark unevenness correction data after the 1401th bit, it is described with 20 × 30 = 600 bits. As a result, in this method, correction data can be described with 1400 + 600 + 7 + 7 = 2014 bits.

  Furthermore, a method of dividing the screen as appropriate and considering the number of correction pattern arrangements and coordinates for each of the divided areas can be adopted.

  That is, in the case of a display device of 360 pixels × 480 pixels, the display screen may be divided into 48 regions of 60 pixels × 60 pixels, and the above-described data description method may be applied to each region. .

  For example, suppose that up to eight dark unevenness corrections and bright unevenness corrections are arranged per area (this upper limit value may be determined appropriately for each display device model). At this time, each of the bright unevenness and the dark unevenness can be described in 6 bits, 3 bits in total. Therefore, for example, the number of bright unevenness correction patterns (for example, 5) and the number of dark unevenness correction patterns (for example, 1) to be arranged in the 60 pixel × 60 pixel region at the upper right end of the display screen are set as correction data. Is described in the first 6 bits. In this case, since a natural number of 60 or less can be expressed by 6 bits, (a) position information can be described by 12 bits. Further, (c) which of the four basic correction patterns is selected can be described with 2 bits. Therefore, it can be described in 14 bits to arrange one unevenness correction pattern. Therefore, if there are 5 bright unevenness correction patterns, 70 bits, if there is 1 dark unevenness correction pattern, 14 bits, a total of 6 + 70 + 14 = 90 bits, and the unevenness correction pattern for the first 60 pixels × 60 pixel region The placement method has been described.

  That is, the first 3 bits specify the number of bright unevenness correction patterns included in the first 60 pixels × 60 pixel region, and the next 3 bits specify the dark unevenness correction patterns included in the first 60 pixels × 60 pixel region. Number is specified. Then, if n bright unevenness correction patterns and m dark unevenness correction patterns are designated, the next (14 × n) bits are used to determine the position and type of bright unevenness correction patterns (the four correction patterns). In addition, the arrangement position and the type of the dark unevenness correction pattern are described for the following (14 × m) bits. Then, after the next bit, that is, the (3 + 3 + 14 × n + 14 × m + 1) -th and subsequent bits, the correction method for the next 60 pixel × 60 pixel region is described. Considering the case where there are 100 bright and dark unevenness corrections in this way, the display screen is divided into 48 regions, each of which specifies the number of correction patterns with 6 bits and correction. Since the position information and type of the pattern are specified by 14 bits per place, the correction method can be described by 6 × 48 + 14 × 100 = 1688 bits.

  In the above method, when a correction pattern is not included in a certain 60 pixel × 60 pixel area, the correction data of that area is described as [000000]. When uncorrected areas are continuous, this can be described by arranging [000000] in a continuous number. This is a method similar to the method in which the uncorrected line pixel group is described by [0] in FIG. Here, it is also possible to apply the method of FIG. That is, a method of designating how many non-correction areas continue by using several bits after [000000] may be used. In a display screen model in which uneven brightness is concentrated on a specific portion of the display screen and the continuity of uncorrected areas tends to increase, this method can further reduce the amount of data.

  Note that the basic correction pattern is spread over a certain range on the display screen, and the position information when arranging the basic correction pattern is determined by appropriately set rules such as center coordinates or end coordinates. Reference coordinates. Therefore, the non-correction area in the above means that the reference coordinates are not included in the area, and does not necessarily mean that no adjustment correction pixel is included in the area. In some cases, the basic correction pattern arranged in the adjacent area extends to the non-correction area, and the correction correction pixel may be included in the non-correction area.

  In this way, the correction information is converted into binary correction signal data of 0/1 by the correction data generation unit 16b, and is output to the drive control unit 22b of the display device 20b.

  FIG. 18 is a block diagram illustrating a configuration of the drive control unit 22b provided in the display device 20b. As shown in this figure, the drive control unit 22b includes a correction data storage unit 31b, a decoding unit 32b, a spatial dispersion processing unit 33b, a time dispersion processing unit 34b, an addition processing unit 35, a first latch unit 36, and a second latch unit. 37, a D / A conversion unit 38, and a correction pattern storage unit 39. Note that an image data correction unit is formed by the spatial dispersion processing unit 33b, the time dispersion processing unit 34b, and the addition processing unit 35. The correction pattern storage unit 39 stores in advance the basic correction pattern shown in FIG. 20 and the correction pattern shown in FIG.

  The correction data storage unit 31b is a non-volatile memory that stores correction data input from the correction data creation device 10b when the display device 20b is inspected. The correction data described as a binary signal according to the method described above is stored here.

  When the display unit 20b displays an image corresponding to the image data on the display panel 21, the decoding unit 32b reads the correction data stored in the correction data storage unit 31b, decodes the correction data, and performs gradation correction information. And output to the spatial distribution processing unit 33b.

  The spatial dispersion processing unit 33b sets the position of the adjustment correction pixel in each luminance unevenness region based on the correction data input from the decoding unit 32b, and the gradation correction information indicating the setting result is sent to the time dispersion processing unit 34b. Output.

  Specifically, the spatial dispersion processing unit 33b detects the correction pattern and the basic correction pattern from the gradation correction information input from the decoding unit 32b, and stores the correction pattern and the basic correction pattern corresponding to the detection result in the correction pattern storage. The adjustment correction pixel is determined by extracting from the unit 39.

  Based on the correction data input from the spatial dispersion processing unit 33b, the time dispersion processing unit 34b changes the position of the adjustment correction pixel in each block described above for each predetermined period (in this embodiment, for each frame). The correction data indicating the setting result is output to the addition processing unit 35.

  For example, as shown in FIG. 22, the position of the adjustment correction pixel may be changed for each frame by shifting the application position of the arrangement pattern for each frame.

  Note that the order of the spatial dispersion processing unit 33b and the time dispersion processing unit 34b may be reversed. That is, the configuration may be such that the correction data is input from the decoding unit 32b to the time dispersion processing unit 34b, and the correction data is input from the time dispersion processing unit 34b to the spatial dispersion processing unit 33b.

  Functions of the addition processing unit 35, the first latch unit 36, the second latch unit 37, and the D / A conversion unit 38 are substantially the same as those in the first embodiment.

  As described above, the correction data creation device 10b according to the present embodiment displays an image corresponding to the inspection image data of the same gradation on all the pixels of the display panel 21 to capture the display screen, and from the captured data. Luminance data is extracted, and spot-like luminance unevenness is extracted from the extracted luminance data. Then, the position of the correction pattern applied to the correction area corresponding to each luminance unevenness area detected by the luminance unevenness detection unit 15b, the pattern number of the correction pattern (correction pattern information, correction pattern identification information), dark spot-like unevenness Correction data composed of information indicating bright spot-like unevenness and the pattern number of the basic correction pattern (basic correction pattern information, basic pattern identification information) is generated and stored in the correction data storage unit 31b provided in the display device 20b. The basic correction pattern is generated based on the variation value of the luminance unevenness amount.

  When the display device 20b displays an image corresponding to the image data on the display panel 21, the correction pattern stored in the correction pattern storage unit 39 based on the correction data stored in the correction data storage unit 31b and An appropriate correction pattern and basic correction pattern are selected from the basic correction patterns, and the luminance unevenness in the correction region corresponding to the luminance unevenness region is corrected. Here, since the basic correction pattern is generated based on the variation value of the luminance unevenness amount, the basic correction pattern can be generated in accordance with the degree of the luminance unevenness amount of the display panel.

  Therefore, it is possible to correct the luminance unevenness with high accuracy and more appropriately prevent the luminance unevenness from being visually recognized.

  In this embodiment, the position of the adjustment correction pixel in each luminance unevenness region is changed every predetermined period (every frame). That is, the adjustment correction pixels are dispersed spatially and temporally in the luminance unevenness region.

  As a result, the visually recognized image can be brought closer to the image when the luminance values of all the pixels in the luminance unevenness region are uniformly changed below the luminance value corresponding to one gradation of the image data. Therefore, it is possible to more appropriately prevent the luminance unevenness from being visually recognized.

  In the present embodiment, correction for a correction region corresponding to a region where spot-like luminance unevenness occurs is performed using four types of basic correction patterns for each of bright spot-like unevenness and dark spot-like unevenness. Thereby, the correction data indicates the position information of the correction area corresponding to each luminance unevenness area (or the position information of the position to which the correction pattern is applied), the correction pattern number, and whether the spot is uneven bright or dark. Since it is only necessary to include four parameters of information and information indicating the basic correction pattern, the amount of correction data is reduced to reduce the storage capacity required for the correction data storage unit 31b provided in the display device 20b. Can do.

[Embodiment 3]
Still another embodiment of the present invention will be described. For convenience of explanation, members having the same functions as those described in the first and second embodiments are denoted by the same reference numerals, and description thereof is omitted.

  In the first embodiment, a configuration for correcting streaky luminance unevenness is described, and in the second embodiment, a configuration for correcting speckled luminance unevenness is described. However, in the present embodiment, streaky luminance unevenness and speckled luminance unevenness are described. A configuration example in the case of correcting both will be described.

  FIG. 23 is a block diagram showing a configuration of the correction data creation device 10c according to the present embodiment. As shown in this figure, the correction data creation device 10c includes a moving average processing unit 14b, a luminance unevenness detection unit 15b, and a correction data generation unit 16b in addition to the configuration of the correction data creation device 10 in the first embodiment. ing. As a result, the correction data generation unit 16 generates correction data for correcting the stripe-shaped luminance unevenness and outputs the correction data to the drive control unit 22c of the display device 20c, and the correction data generation unit 16b performs the spot-shaped luminance unevenness. Correction data for correcting this is generated and output to the drive control unit 22c of the display device 20c. The generation method of each correction data is the same as in the first and second embodiments.

  FIG. 24 is a block diagram illustrating a configuration of a drive control unit 22c included in the display device 20c according to the present embodiment. As shown in this figure, in addition to the drive control unit 22 in the first embodiment, the drive control unit 22c includes a correction data storage unit 31b, a decoding unit 32b, a spatial dispersion processing unit 33b, a time dispersion processing unit 34b, and a correction pattern. A storage unit 39 is provided. The correction data storage unit 31, the decoding unit 32, the spatial dispersion processing unit 33, and the time dispersion processing unit 34 constitute a first correction unit for correcting streaky luminance unevenness, and the correction data storage unit 31b and decoding The unit 32b, the spatial dispersion processing unit 33b, the time dispersion processing unit 34b, and the correction pattern storage unit 39 constitute a second correction unit for correcting spot-like luminance unevenness.

  The addition processing unit 35 corrects the stripe-shaped luminance unevenness input from the time dispersion processing unit 34 and the spot-like luminance unevenness input from the time dispersion processing unit 34b. The image data is corrected based on the correction data.

  For the pixels selected as adjustment correction pixels in both the correction data for correcting the stripe-like luminance unevenness and the correction data for correcting the spot-like luminance unevenness, the maximum correction value of the gradation value is set. It may be set to 1 gradation or 2 gradations. For example, in the case of an adjustment correction pixel in a region corresponding to a bright streak-like luminance unevenness region and a bright spot-like luminance unevenness region, the gradation value of the adjustment correction pixel may be lowered by two gradations. Only the key may be lowered.

  In the present embodiment, with the above configuration, both streaky luminance unevenness and speckled luminance unevenness can be corrected so that they are not easily recognized as luminance unevenness.

  In the present embodiment, a processing unit (correction data storage unit 31, decoding unit 32, spatial dispersion processing unit 33, and time dispersion processing unit 34) for correcting streaky luminance unevenness, and spot-like luminance unevenness. Are separately provided with a processing unit (correction data storage unit 31b, decoding unit 32b, spatial dispersion processing unit 33b, time dispersion processing unit 34b, and correction pattern storage unit 39).

  Regarding the description method of the correction data, the correction data related to the correction of the streaky luminance unevenness is described using the method of the first embodiment, and the correction data related to the correction of the spotted luminance unevenness is used of the method of the second embodiment. Can be described.

  That is, in order to describe correction information for streaky luminance unevenness as correction data, luminance unevenness is analyzed and divided into a plurality of stages, and the display screen is displayed for each line pixel group extending in the direction of streaky unevenness. For each line pixel group, (a) whether correction is performed, (b) dark unevenness correction or bright unevenness correction, and (c) which correction intensity group is described. That's fine. When only one of dark unevenness correction and bright unevenness correction is performed, the information related to (b) can be omitted. With this method, correction information can be described with a small amount of data.

  In addition, in order to describe correction information for speckle-shaped luminance unevenness as correction data, a basic correction pattern is separately stored in a table, and (a) the basic correction pattern is arranged at any position on the display screen. Or (b) whether to apply bright unevenness correction or dark unevenness correction (this bit can be omitted when only bright unevenness correction or dark unevenness correction is performed), or (c) basic correction of the table What is necessary is just to describe by the information of which to choose from the pattern.

  In other words, the description of the correction data relating to the correction of streaky luminance unevenness is performed with respect to the line pixel group to be corrected after designating whether or not to correct each of the line pixel groups in which the display screen is virtually divided. Describes the correction method. On the other hand, the description of the correction data regarding the correction of the spot-like luminance unevenness takes a description method in which the position and the correction method are individually specified for the region to be corrected. As described above, the correction description method is changed for the correction of streaky luminance unevenness and the correction of spotted luminance unevenness, respectively. The former is a description of the correction method including information on the presence or absence of correction for each area of the divided display screen, By describing the basic correction pattern arrangement method, the data amount of all correction data can be reduced. Both data may be stored in a predetermined area of the correction data storage unit 31 or may be stored continuously with information specifying the boundary between the two data.

  As for the former information, it is not always necessary to describe a correction method for the entire area of the display screen. For example, the peripheral portion of the display screen is not conspicuous even if there is uneven brightness, and the peripheral portion is not corrected. In this case, correction data relating to the peripheral portion is also unnecessary. In short, it is only necessary to divide a display screen range in which at least unevenness is easily visible and to set the presence / absence of correction for each area and the correction method.

  In each of the above embodiments, the correction data creation devices 10, 10b, and 10c are provided separately from the display devices 20, 20b, and 20c. However, the present invention is not limited to this, and the correction data creation devices 10, It is good also as a structure with which some or all of 10b and 10c are provided in the display apparatuses 20, 20b, and 20c. Of the correction data creation devices 10, 10 b, and 10 c, the units other than the imaging unit 12 are provided in the display devices 20, 20 b, and 20 c, and the imaging data acquired by imaging the display screen of the display panel 21 by the imaging unit 12 is displayed on the display device. You may make it input into the correction data production apparatus 10, 10b, 10c provided in 20,20b, 20c.

  Further, in each of the above embodiments, each unit (each block) provided in the correction data creation device 10, 10b, 10c or the drive control device 22, 22b, 22c may be realized by software using a processor such as a CPU. . In this case, each block includes a CPU (central processing unit) that executes instructions of a control program that realizes each function, a ROM (read only memory) that stores the program, and a RAM (random access memory) that expands the program. And a storage device (recording medium) such as a memory for storing the program and various data. An object of the present invention is to provide a recording medium in which a program code (execution format program, intermediate code program, source program) of the control program for each block, which is software that realizes the functions described above, is recorded so as to be readable by a computer. This is achieved by supplying the correction data creation device 10, 10b, 10c or the drive control device 22, 22b, 22c and reading and executing the program code recorded on the recording medium by the computer (or CPU or MPU).

  Examples of the recording medium include a tape system such as a magnetic tape and a cassette tape, a magnetic disk such as a floppy (registered trademark) disk / hard disk, and an optical disk such as a CD-ROM / MO / MD / DVD / CD-R. Card system such as IC card, IC card (including memory card) / optical card, or semiconductor memory system such as mask ROM / EPROM / EEPROM / flash ROM.

  Further, the correction data creation devices 10, 10b, 10c or the drive control devices 22, 22b, 22c may be configured to be connectable to a communication network, and the program code may be supplied via the communication network. The communication network is not particularly limited. For example, the Internet, intranet, extranet, LAN, ISDN, VAN, CATV communication network, virtual private network, telephone line network, mobile communication network, satellite communication. A net or the like is available. Also, the transmission medium constituting the communication network is not particularly limited. For example, even in the case of wired such as IEEE 1394, USB, power line carrier, cable TV line, telephone line, ADSL line, etc., infrared rays such as IrDA and remote control, Bluetooth ( (Registered trademark), 802.11 wireless, HDR, mobile phone network, satellite line, terrestrial digital network, and the like can also be used. The present invention can also be realized in the form of a computer data signal embedded in a carrier wave in which the program code is embodied by electronic transmission.

  Further, each block of the correction data creation devices 10, 10b, 10c or the drive control devices 22, 22b, 22c is not limited to being realized using software, but may be configured by hardware logic. A combination of hardware that performs a part of the processing and arithmetic means that executes software that controls the hardware and performs the remaining processing may be used.

  In each of the above embodiments, the case where the present invention is applied to a liquid crystal display device has been described. However, the application target of the present invention is not limited to this, and for example, a display device such as a plasma display or an organic EL display. Applicable.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention.

  The present invention can be applied to various display devices such as a liquid crystal display device, a plasma display, and an organic EL display, and a correction data creation device that creates correction data for these display devices.

10, 10b, 10c Correction data creation device 11 Display data generation unit 12 Imaging unit 13 Luminance data extraction unit 14, 14b Moving average processing unit 15, 15b Luminance unevenness detection unit 16, 16b Correction data generation unit 20, 20b, 20c Display Device 21 Display panel 22, 22b, 22c Drive control device 31, 31b Correction data storage unit 32, 32b Decoding unit 33, 33b Spatial dispersion processing unit (image data correction unit)
34, 34b Time dispersion processing unit (image data correction unit)
35 Addition processing unit (image data correction unit)
36 First latch portion 37 Second latch portion 38 D / A conversion portion 39 Correction pattern storage portion (basic correction pattern storage portion)

Claims (9)

A display device comprising: a display screen for displaying an image according to display image data; and a drive control unit for controlling a display state of each pixel of the display screen,
When an image corresponding to the inspection image data is displayed on the display screen, at least one of the luminance unevenness areas, which is an area where an image having a luminance value different from the appropriate luminance value corresponding to the inspection image data is displayed. In the display unevenness region, the difference between the brightness value when the image corresponding to the display image data is displayed and the appropriate brightness value corresponding to the display image data is reduced in the display image data. Created based on the inspection image data for correcting pixel data included in a correction area that is an area corresponding to the at least part of the uneven brightness area or an area including the uneven brightness area and its peripheral area. When the image corresponding to the display image data is displayed on the display screen using the corrected data, at least some of the pixels included in the correction area are displayed. Comprising an image data correction unit for correcting the display image data so as to change the gradation value of the unit,
The correction data includes a luminance value of each pixel when an image corresponding to the inspection image data is displayed on the display screen or a luminance value of each pixel group obtained by dividing each pixel into a plurality of pixels, and and the optimum luminance value of each pixel or the pixel group corresponding to the test image data, depending on the variation value of the quantity luminance unevenness is the difference, group information grouping the correction region corresponding to each luminance unevenness regions And correction information indicating the content of correction for each group associated with the group information,
The image data correction unit determines a pixel whose gradation value is changed in each correction region based on a grouping result for each correction region,
The display apparatus according to claim 1, wherein the drive control unit controls a display state of each pixel so as to display an image corresponding to the display image data corrected by the image data correction unit.   2. The appropriate luminance value is a moving average value of luminance values of imaging data obtained by imaging the display screen in a state where an image corresponding to the inspection image data is displayed. The display device described in 1. The correction information includes correction necessity information indicating whether correction is to be performed, and, for the pixel group to be corrected, whether the correction is to increase or decrease the gradation value of at least some of the pixels. The display device according to claim 1, wherein the display device includes corrected gradation information. When correction for increasing or decreasing the gradation value of a pixel is continuously performed in adjacent pixel groups,
  The correction gradation information is given only to the pixel group to be corrected first among the adjacent pixel groups, and other pixel groups are corrected with reference to the correction gradation information. The display device according to claim 3. When pixel groups that do not perform correction are continuous,
  5. The display device according to claim 3, wherein the correction information given to the first pixel group that is not corrected includes information indicating how many pixel groups that are not corrected continue. A brightness unevenness correction method for correcting brightness unevenness of the display screen in a display device including a display screen for displaying an image according to display image data,
  When an image corresponding to the inspection image data is displayed on the display screen, at least one of the luminance unevenness areas, which is an area where an image having a luminance value different from the appropriate luminance value corresponding to the inspection image data is displayed. For the luminance unevenness area of the portion, the display image is reduced so as to reduce the difference between the luminance value when the image corresponding to the display image data is displayed and the appropriate luminance value corresponding to the display image data. Created based on the inspection image data for correcting pixel data included in a correction area, which is an area corresponding to at least a part of the luminance unevenness area in the data or an area including the luminance unevenness area and its peripheral area Correction data storing step for storing the corrected data,
  When displaying an image according to the display image data on the display screen, the gradation value of at least some of the pixels included in the correction region is changed based on the correction data. An image data correction step for correcting display image data;
  A drive control step of controlling the display state of each pixel so as to display an image according to the display image data corrected by the image data correction step,
  The correction data includes a luminance value of each pixel when an image corresponding to the inspection image data is displayed on the display screen or a luminance value of each pixel group obtained by dividing each pixel into a plurality of pixels, and Group information in which correction areas corresponding to each luminance unevenness region are grouped according to a variation value of the luminance unevenness amount that is a difference between the appropriate luminance value of each pixel or each pixel group corresponding to the inspection image data And correction information indicating the content of correction for each group associated with the group information,
  In the image data correction step, a luminance unevenness correction method characterized in that a pixel whose gradation value is changed in each correction area is determined based on a grouping result for each correction area. 7. The appropriate luminance value is a moving average value of luminance values of imaging data obtained by imaging the display screen in a state where an image corresponding to the inspection image data is displayed. The brightness unevenness correction method described in 1.   A correction data creation device for creating the correction data in the display device according to any one of claims 1, 2, and 3-5,
  The luminance value of each pixel in the imaging data obtained by imaging the display screen in a state where an image corresponding to the inspection image data is displayed, or the luminance value of each pixel group obtained by dividing each pixel into a plurality of pixels The difference between the appropriate luminance value corresponding to the inspection image data is calculated, and an area including a set of pixels or pixel groups in which the calculated magnitude of the difference is greater than or equal to a predetermined threshold is defined as a luminance unevenness area. A luminance unevenness detection unit to detect;
  For at least some of the brightness unevenness areas, the difference between the brightness value when displaying an image corresponding to the display image data and the appropriate brightness value corresponding to the display image data is reduced. As described above, correction data for correcting pixel data included in a correction area that is an area corresponding to the at least part of the luminance unevenness area in the display image data or an area including the luminance unevenness area and its peripheral area. And a correction data generation unit for creating the image data based on the inspection image data,
  The correction data generation unit
  Corresponds to the luminance value of each pixel when the image corresponding to the inspection image data is displayed on the display screen or the luminance value of each pixel group obtained by dividing each pixel into a plurality of pixels, and the inspection image data Group information in which correction areas corresponding to each luminance unevenness region are grouped according to a variation value of the luminance unevenness amount, which is a difference between the appropriate luminance value of each pixel or each pixel group, and the group information A correction data creating apparatus characterized in that the correction data includes correction information indicating the contents of correction for each group. A correction data creation method for creating the correction data in the display device according to any one of claims 1, 2, and 3-5,
  Displaying an image corresponding to the image data for inspection on the display screen;
  Imaging the display screen in a state where an image corresponding to the inspection image data is displayed, and obtaining imaging data;
  The difference between the luminance value of each pixel in the imaging data or the luminance value of each pixel group obtained by dividing each pixel into a plurality of pixels and the appropriate luminance value corresponding to the inspection image data is calculated and calculated. A luminance unevenness detecting step of detecting, as a luminance unevenness region, an area formed of a set of pixels or pixel groups having a difference magnitude equal to or greater than a predetermined threshold;
  For at least some of the brightness unevenness areas, the difference between the brightness value when displaying an image corresponding to the display image data and the appropriate brightness value corresponding to the display image data is reduced. As described above, correction data for correcting pixel data included in a correction area that is an area corresponding to the at least part of the luminance unevenness area in the display image data or an area including the luminance unevenness area and its peripheral area. Including a correction data generation step for creating a correction data based on the inspection image data,
  In the correction data generation step,
  Corresponds to the luminance value of each pixel when the image corresponding to the inspection image data is displayed on the display screen or the luminance value of each pixel group obtained by dividing each pixel into a plurality of pixels, and the inspection image data Group information in which correction areas corresponding to each luminance unevenness region are grouped according to the variation value of the luminance unevenness amount, which is a difference between the appropriate luminance value of each pixel or each pixel group to be used, and the group information A correction data generation method, characterized in that the correction data includes correction information indicating the contents of correction for each group.

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