JP2006018169A - Image display apparatus and its temperature correction method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce irregular temperature distribution on a light emitting surface of a display panel by a circuit means. <P>SOLUTION: A display panel 1 has a light emitting surface composed of pixels comprising light emitting elements and displays an image by emitting light in accordance with display data, however, the panel shows typical irregularity in the temperature distribution on the light emitting surface accompanying local deviation of heat generation and heat radiation by light emission of each light emitting element. A correction pattern generating means 2 generates correction pattern data representing a display pattern corresponding to a typical irregularity of the temperature distribution. A display data converting circuit 3 converts the externally inputted display data based on the generated correction pattern data and thereby, supplies the correction display data capable of correcting the typical irregularity of the temperature distribution to the display panel 1 so as to allow each light emitting element to emit light in accordance with the corrected display data to display an image. Thus, irregularity in the temperature distribution on the light emitting surface of the display panel can be reduced. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image display device including a module including a display panel. More specifically, the present invention relates to a technique for mitigating uneven temperature distribution on a light emitting surface constituting a screen of a display panel using circuit means.

  Flat panel displays are widely used in products such as computer displays, portable terminals, and televisions. Currently, liquid crystal display panels are mainly used, but the narrow viewing angle and slow response speed continue to be pointed out. On the other hand, an organic EL display formed of a self-luminous element can overcome the above-mentioned viewing angle and responsiveness problems, and can achieve a thin form, high brightness, and high contrast that do not require a backlight. It is expected as an alternative next-generation display device.

  By the way, it is generally known that a light emitting element in an organic EL display has a characteristic that the light emitting element deteriorates in proportion to the amount of light emission and time. At the same time, the deterioration rate varies depending on the temperature of the element itself. It is also known that it is a big problem. Since the organic EL light emitting element is a self-luminous type, it generates heat during operation and generates a higher amount of current as it achieves higher luminance, and generates heat at a higher temperature. It is also known that the higher the temperature, the faster the deterioration.

On the other hand, flat panel displays always have the following two temperature irregularities. This is not due to the display pattern, but due to the shape and arrangement. The first is a temperature drop due to heat conduction of the outer peripheral light emitting part to the outer adjacent frame non-light emitting part. Since there is no light emitting element in the frame portion, the temperature is always equal to or lower than the light emitting portion, and the temperature of the outer peripheral light emitting portion can be lowered by conducting heat there. This was confirmed by measurement that in an organic EL display panel using glass, an area of about 20 mm from the outer periphery to the inner side was most affected.

  The second is a temperature drop caused by cooling the lower part of the light emitting part by air convection. A flat panel display is generally used in an upright position as the size increases, and air convection tends to occur near the light emitting portion. At the lower end, air at a temperature close to the surrounding environment convects, so that the temperature of the light emitting section is lowered. However, since the air convection in the vicinity of the light emitting part is warmed by the heat of the light emitting part as it goes upward, the temperature of the light emitting part cannot be lowered beyond a certain distance. This was also confirmed by measurement to be most affected in an area of about 200 mm from the lower end.

  That is, in the light emitting surface formed by the light emitting element of the display panel, even if light is emitted uniformly with the same gradation data, the temperature unevenness due to the above-mentioned causes occurs, and the temperature is high. As a result of the difference in deterioration rate between the low and high areas, and the decrease in brightness progresses quickly in the high temperature area, the same area as the temperature unevenness appears as uneven brightness lifetime deterioration (standard brightness unevenness). Therefore, it was necessary to make the temperature distribution in the light emitting surface as uniform as possible.

As a prior art, there are the following patent documents.
JP 2003-295776 JP 2003-263131 A JP 2003-330419 A

  In Patent Document 1, the temperature controller is controlled from the temperature detected from the light emitting element and the information assuming the transition of the temperature rise, and the temperature in the light emitting surface is made uniform by heating or cooling the regionized portion. adjust. This can actually detect the temperature and control the temperature to be constant, but it is necessary to provide a temperature detection structure and a structure such as a temperature controller, which makes the structure complicated and leads to an increase in cost. In addition, there is a problem that adjustment is possible only in a partitioned area and control cannot be performed in units of one pixel. Patent Document 2 accumulates luminance information of display data, and changes the display data so that the estimated amount of deterioration is averaged from the accumulated information. This is because the display data is changed, and thus it is possible to relatively easily correct luminance unevenness in units of one pixel. However, only the deterioration characteristics due to the light emission amount and time of the light emitting element are considered, and the deterioration rate due to temperature unevenness There is a problem that the luminance unevenness due to the difference between the two cannot be corrected. Patent Document 3 refers to the temperature characteristic of the voltage-current characteristic of the light-emitting element stored in the device from the detected ambient temperature, and corrects the display data so as to obtain an appropriate luminance. This is intended to make the light emission luminance constant in any environment, and a detection means such as a temperature sensor is required, and since it is the environmental temperature that is detected, in-plane temperature unevenness is detected. It was not a thing. That is, there has been a problem that luminance unevenness caused by a difference in deterioration rate due to in-plane temperature unevenness cannot be corrected.

  In other words, until now, when trying to correct temperature unevenness, most of the techniques are to provide a new structure that dissipates heat or gives heat, and there is a problem of increasing costs. Further, in the case of correcting image sticking and luminance unevenness, there is only a problem of correcting unevenness in luminance deterioration caused by display data, and there is a problem that a difference in deterioration rate generated due to temperature unevenness cannot be corrected.

  In view of the above-described problems of the conventional technology, an object of the present invention is to alleviate unevenness in temperature distribution on the light emitting surface of a display panel by circuit means. In order to achieve this purpose, the following measures were taken. That is, the present invention is an image display device including a module including a display panel, a display data conversion circuit, and a correction pattern generation unit, and the display panel includes a light emitting surface composed of pixels formed of light emitting elements. The light emission is displayed according to display data and an image is displayed, and the irregularity in the temperature distribution of the light emitting surface is generated due to the heat generated by the light emission of each light emitting element and the local deviation of the heat dissipation, and the correction pattern The generation unit generates correction pattern data representing a display pattern corresponding to the regular unevenness of the temperature distribution, and the display data conversion circuit displays a display input from the outside based on the generated correction pattern data Data is converted, and thus corrected display data that can correct typical irregularities in the temperature distribution is supplied to the display panel. By emitting element by displaying an image, characterized by relaxing the unevenness of the temperature distribution of the light emission surface of the display panel.

  Preferably, the correction pattern generation means corrects a non-uniformity in the outer periphery temperature that corrects a typical unevenness in the temperature distribution caused by a temperature drop due to heat conduction from the outer periphery surrounding the central portion of the light emitting surface to the adjacent non-light emitting portion. Peripheral temperature unevenness correction pattern storage means storing pattern data, and lower temperature unevenness correction pattern data for correcting typical unevenness of temperature distribution caused by temperature drop caused by cooling the lower part of the light emitting surface by air convection By combining the lower temperature unevenness correction pattern storage means storing the outer peripheral temperature unevenness correction pattern data and the lower temperature unevenness correction pattern data, it is possible to correct typical unevenness of the temperature distribution of the entire light emitting surface. Temperature non-uniformity correction pattern synthesizing means for supplying various synthetic correction pattern data to the display data conversion circuit. Preferably, display data information detecting means for detecting an average value of frame gradation from display data representing a multi-gradation image input from outside in units of frames, and frame gradation obtained from the display data information detecting means. A correction level control circuit for controlling the correction level of the correction pattern data generated by the temperature unevenness correction pattern generation means according to the average value. Alternatively, display data information detecting means for extracting the position of the object on the light emitting surface from display data representing an image including the object input from the outside, and the position of the object obtained from the display data information detecting means And a correction level control circuit for controlling the correction level of the correction pattern data generated by the temperature unevenness correction pattern generating means. Further, the light emitting surface of the display panel has a correction area whose temperature is lower than others and needs to be corrected along the regular unevenness of the temperature distribution, and the correction pattern generation means displays the display corresponding to the correction area. Correction pattern data representing a pattern is generated, and the display data conversion circuit adds the generated correction pattern data to display data input from the outside, thereby correcting the unevenness of the temperature distribution. Is generated. Alternatively, the light emitting surface of the display panel has a correction region whose temperature is lower than that of other regions and needs to be corrected along the regular unevenness of the temperature distribution, and the correction pattern generation unit excludes the correction region. The correction pattern data representing the display pattern corresponding to the other region is generated, and the display data conversion circuit subtracts the generated correction pattern data from the display data input from the outside, thereby correcting the unevenness of the temperature distribution. Correction display data that can correct the above is generated.

  In addition, the present invention has a light emitting surface composed of a set of pixels composed of light emitting elements, emits light according to display data, displays an image, and generates local heat and heat dissipation due to light emission of each light emitting element. A temperature correction method for an image display apparatus including a display panel having a typical unevenness in the temperature distribution of the light emitting surface, and generating correction pattern data representing a display pattern corresponding to the regular unevenness in the temperature distribution And display data input from the outside based on the generated correction pattern data, and supply corrected display data capable of correcting typical irregularities in the temperature distribution to the display panel. And the unevenness of the temperature distribution on the light emitting surface of the display panel is reduced by causing each light emitting element to emit light with the corrected display data and displaying an image. .

  According to the present invention, it is possible to avoid the temperature drop that occurs in the light emitting outer peripheral part and the light emitting lower part region by emitting light with higher brightness than the normal display data and increasing the temperature, and to keep the temperature uniform over the light emitting surface. Therefore, there is an effect that a difference in deterioration rate of the organic EL light emitting element can be suppressed and a typical luminance unevenness due to pixel deterioration can be prevented. According to the present invention, since the temperature unevenness correction level can be appropriately changed by the input display data signal, the temperature can be kept substantially uniform over the light emitting surface without greatly degrading the display quality such as brightness unevenness. There is an effect that can be done. According to the present invention, since temperature unevenness can be corrected without requiring a special structure on the mechanism, there is an effect that costs can be kept low.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing the overall configuration of an image display apparatus according to the present invention. As shown in the figure, the image display apparatus includes a module 1 including a display panel, a display data conversion circuit 3, and a correction pattern generation unit 2. The display panel has a light emitting surface composed of pixels composed of light emitting elements, emits light according to display data, displays an image, and generates heat due to light emission of each light emitting element and local deviation of heat dissipation. Regular irregularities occur in the temperature distribution on the light emitting surface. The correction pattern generation means 2 generates correction pattern data representing a display pattern corresponding to the regular unevenness of the temperature distribution. The display data conversion circuit 3 converts display data input from the outside based on the generated correction pattern data, and thereby displays corrected display data that can correct the regular unevenness of the temperature distribution on the display panel. By supplying and displaying the image by causing each light emitting element to emit light with the corrected display data, the unevenness of the temperature distribution on the light emitting surface of the display panel is alleviated.

  Specifically, the correction pattern generation unit 2 corrects the irregular temperature irregularity that corrects the typical irregularity of the temperature distribution caused by the temperature drop due to the heat conduction from the outer periphery surrounding the central portion of the light emitting surface to the adjacent non-light emitting portion. Peripheral temperature unevenness correction pattern storage means 21 in which correction pattern data is stored, and a lower temperature unevenness correction pattern for correcting a typical unevenness in temperature distribution caused by a temperature drop caused by cooling the lower part of the light emitting surface by air convection. Lower temperature unevenness correction pattern storage means 22 in which data is stored, outer peripheral temperature unevenness correction pattern data, and lower temperature unevenness correction pattern data are synthesized to correct typical unevenness of the temperature distribution of the entire light emitting surface. It comprises temperature unevenness correction pattern synthesis means 23 for supplying possible synthesis correction pattern data to the display data conversion circuit 3.

  The light emitting surface of the display panel has a correction region whose temperature is lower than others and needs to be corrected, along with the regular unevenness of the temperature distribution. In this case, the correction pattern generation unit 2 generates correction pattern data representing a display pattern corresponding to the correction area. The display data conversion circuit 3 generates corrected display data that can correct unevenness in temperature distribution by adding the generated correction pattern data to externally input display data. Alternatively, the correction pattern generation unit 2 may generate correction pattern data representing a display pattern corresponding to another area excluding the correction area. In this case, the display data conversion circuit 3 generates corrected display data that can correct the unevenness of the temperature distribution by subtracting the generated correction pattern data from the externally input display data.

  Hereinafter, the first embodiment shown in FIG. 1 will be described in detail with reference to FIGS. First, for the display panel to be corrected, the temperature distribution is measured in a state where the light emitting unit is operated to emit light at the maximum in-plane uniform gradation and is placed horizontally with respect to the ground. In the temperature distribution, temperature unevenness as shown in FIG. 2 due to a temperature drop due to heat conduction to the outer adjacent frame non-light emitting portion is observed in the outer peripheral light emitting portion. The plan view of FIG. 2 schematically shows the surface temperature distribution of the panel 1. As shown in the drawing, the temperature of the peripheral portion is lower than that of the central portion of the light emitting surface 100, and this is a region where temperature unevenness occurs. Compared with the central portion of the light emitting surface 100, the peripheral portion loses heat due to heat conduction or the like, and therefore the temperature is low.

  The graph included in FIG. 2 represents the temperature distribution of the corner portion of the panel 1 and the portion along the diagonal line (shown by a one-dot chain line). This graph shows distance on the horizontal axis and temperature on the vertical axis. As is apparent from the graph, it can be seen that the end portion has a temperature lower than the center of the light emitting surface over a width of about 20 mm. This is because in an organic EL display panel using glass, an area of about 20 mm from the outer periphery is most affected, and this area is set as a main correction area 1.

  At the same time, the temperature distribution is measured in a state of being placed vertically following the actual use state. The temperature distribution measured here is subtracted from the temperature distribution measured in the horizontal state as described above, as temperature unevenness due to a temperature drop caused by cooling the lower part of the light emitting surface due to air convection at the lower part of the light emitting surface. Observed. FIG. 3 is a schematic diagram showing the deviation of the temperature distribution between the upper and lower sides of the panel. As shown in the drawing, the light emitting surface 100 is a region where the temperature of the lower part is lower than that of the upper part and temperature unevenness occurs. This is because when the panel 1 is placed upright, the lower part is relatively strongly cooled by the convection of the cooling air. The temperature distribution at the bottom of panel 1 is shown in the graph. As is apparent from the graph, it can be seen that the temperature at the bottom of the panel is lower at a width of about 200 mm than at the top and center of the panel. This is because it is most affected in an area of about 200 mm from the lower end, and this area is set as the main correction area 2.

  At the same time, the gradation-temperature rise characteristic is measured in a region in the panel that is not affected by the temperature drop. The gradation-temperature rise characteristic is often shown in FIG. 4 in a general organic EL display. It can be seen that heat is generated at a higher temperature because a larger amount of current is required as the gradation is increased and the luminance is increased.

  The correction value information as shown in FIG. 5 is calculated based on the information obtained from these, and is used to increase the gradation data in the outer peripheral light emitting portion temperature lowering portion of the main correction region 1 so that the temperature is the same in the surface. Is stored in the outer periphery temperature unevenness correction pattern storage means. In the illustrated graph, the vertical axis represents the gradation level of the display data, and the horizontal axis represents the distance from the center of the panel toward the outermost peripheral edge of the light emitting surface. A curve indicated by a one-dot chain line on the graph represents input display data, and a curve indicated by a solid line represents corrected display data. Corrected display data can be obtained by adding the hatched data to the input display data. That is, the shaded portion is the outer periphery temperature unevenness correction pattern data. By this outer peripheral temperature unevenness correction pattern data, the input display data is corrected to display data by lifting a portion corresponding to the outer peripheral portion of the light emitting surface. The display panel displays an image based on the corrected display data. Since the light emitting elements of the pixels located on the outer peripheral portion of the light emitting surface emit light at a gradation level higher than that of the original input display data, the amount of heat generation is increased accordingly. With this increase in the amount of heat generation, the temperature distribution is made uniform over the entire light emitting surface by compensating for the low temperature unevenness in the outer peripheral portion.

  Further, in the lower light emitting surface temperature lowering portion of the main correction region 2, correction value information as shown in FIG. 6 for increasing the gradation data to be the same temperature in the surface is stored in the lower temperature unevenness correction pattern storage means. Stored. In the illustrated graph, the vertical axis represents the gradation level of the display data, and the horizontal axis represents the distance from the center of the panel to the lowermost end of the light emitting surface. Assuming that the input display data has a constant gradation level over the entire panel light emitting surface as indicated by the alternate long and short dash line, the correction display data indicated by the solid line has an increased gradation level in the range of about 200 mm below the light emitting surface. . In other words, corrected display data can be obtained by adding to the input display data the gradations indicated by hatching. The hatched portion is the lower temperature unevenness correction pattern data. The lower temperature unevenness correction pattern data is set so as to correct low temperature unevenness at the lower portion of the light emitting surface. In other words, the light emitting element located at the bottom of the display panel emits light according to the corrected display data, but the brightness is increased because the gradation level is set higher than the original input display data, and the amount of heat generation is also correspondingly increased. To increase. The increased amount of heat generation compensates for low temperature unevenness at the lower part of the light emitting surface. The gradation level difference between the input display data and the corrected display data is set within a range that does not affect the image quality.

  Next, in the temperature unevenness correction pattern synthesis means, the correction value information stored in the outer periphery temperature unevenness correction pattern storage means and the correction value information stored in the lower temperature unevenness correction pattern storage means are added. Then, correction value information for the entire panel is generated. Thereby, correction value information as shown in FIG. 7 is generated. FIG. 7 is a schematic diagram showing a combined temperature unevenness correction pattern in which the outer periphery temperature unevenness correction pattern shown in FIG. 5 and the lower temperature unevenness correction pattern shown in FIG. 6 are combined. The light emitting surface 100 of the panel 1 includes an outer peripheral temperature nonuniformity region and a lower temperature nonuniformity region whose temperature is lower than that of the central region. The outer periphery temperature unevenness correction pattern for correcting the outer periphery temperature unevenness and the lower temperature unevenness correction pattern for correcting the lower temperature unevenness are combined to obtain a combined temperature unevenness correction pattern shown in the graph of FIG. The illustrated graph represents a combined temperature unevenness correction pattern along the central vertical line of the light emitting surface 100. In the graph, the vertical axis represents the display data gradation level, and the horizontal axis represents the vertical position of the light emitting surface 100. If the input display data is at a constant gradation level over the entire light emitting surface, the corrected display data is a curve with increased gradation levels near the uppermost end of the light emitting surface and the lowermost end of the light emitting surface as shown by the solid line. . This curve is a synthetic temperature unevenness correction pattern. As is apparent from the graph, the gradation of the corrected display data is increased in the vicinity of about 20 mm near the uppermost end of the light emitting surface and about 20 mm near the lowermost end of the light emitting surface. This increase is attributed to the peripheral temperature unevenness correction pattern. Further, the gradation level of the corrected display data is increased in the range of about 200 mm near the lowermost end of the light emitting surface. This rise is where the lower temperature unevenness correction pattern contributes. The gradation level is higher in the portion with a width of about 20 mm near the lowermost end of the light emitting surface than in the other portions. This portion corresponds to a portion in which the outer periphery temperature unevenness correction pattern and the lower temperature unevenness correction pattern are substantially combined.

  The correction value information generated by the temperature unevenness correction pattern synthesis means is output to the display data conversion circuit. The display data conversion circuit performs data conversion based on the correction value information mainly in the main correction areas 1 and 2 from the input display data signal. Display is performed. The corrected display data signal output from the display data conversion circuit is not necessarily the same information amount as the input display data signal. That is, there is a case where conversion is performed by increasing the number of bits in order to perform correction without a sense of incongruity without losing the original gradation information. By doing so, it is also possible to ensure the gradation reproducibility of the high gradation data. As described above, according to the present invention, it is possible to avoid the temperature decrease that occurs in the light emitting outer peripheral portion and the light emitting lower region by emitting light with higher brightness than the normal display data and increasing the temperature. Therefore, there is an effect that a difference in deterioration rate of the organic EL light emitting element can be suppressed, and regular luminance unevenness due to pixel deterioration can be prevented.

  According to the first embodiment described above, it is possible to substantially correct the temperature unevenness, but since the brightness is positively increased and corrected in an area where the temperature is lowered, the brightness unevenness is caused when the correction width is large. There is a concern of being recognized. Therefore, a second embodiment shown in FIG. 8 will be described. The operation of the temperature unevenness correction pattern generation unit 2 is the same as that of the first embodiment shown in FIG. The difference is that the display data information detection means 4 for detecting the frame gradation average value from the display data representing the multi-gradation image input from the outside in units of frames, and the frame level obtained from the display data information detection means 4. And a correction level control circuit 5 for controlling the correction level of the correction pattern data generated by the temperature unevenness correction pattern generation means 2 according to the tone average value. Alternatively, the display data information detecting means 4 for extracting the position of the object on the light emitting surface from the display data representing the image including the object input from the outside, and the position of the object obtained from the display data information detecting means 4 The correction level control circuit 5 controls the correction level of the correction pattern data generated by the temperature unevenness correction pattern generation means 2.

  According to the present embodiment, the correction value information generated by the temperature unevenness correction pattern generation unit 2 is output to the correction level control circuit 5. On the other hand, the display data information detection means 4 calculates and detects the average value of one frame of the input display data signal and the display position information of the object, and outputs the same to the correction level control circuit 5. The correction level control circuit 5 controls the correction value level input from the temperature unevenness correction pattern generation means 2 based on the information obtained from the display data information detection means 4 and outputs it to the display data conversion circuit 3. The correction value level control is obtained by setting the correction value level obtained in the first embodiment to 1, and multiplying by a correction coefficient less than that.

  FIG. 9 shows an example of a method for determining the correction coefficient. FIG. 9 is a graph showing a temperature unevenness correction pattern, and four lines are shown taking the frame gradation average value as a parameter. This frame gradation average value is extracted from display data input from the outside, and represents the average luminance of the screen. When the average brightness of the screen is brighter than a predetermined threshold, the basic correction level shown in FIG. 7 is adopted. Conversely, when the screen brightness is lower than another threshold value and considerably dark, the correction level is zero. If the screen brightness is neither bright nor dark, an intermediate correction level is adopted. This intermediate correction level is obtained by multiplying the basic correction level by a correction coefficient in the range of 1 to 0. The correction coefficient is closer to 1 as the screen brightness is higher, and closer to 0 as the screen brightness is lower.

  In general, large temperature unevenness occurs when the average luminance in the light emitting surface is high and the temperature is high, and it is not a big problem to suppress the correction level in a dark screen. At the same time, from the viewpoint of human eye sensitivity, it is easier to recognize a luminance difference on a dark screen, so it can be said that it is effective to keep the correction level low while the average value of one frame of gradation is low. Further, when there is no display data in the main correction area, it is not necessary to perform correction, so the correction value level should be lowered. The contents of the above adaptive control are summarized in the table of FIG. As described above, the correction value level should always be conscious of the display quality, and the detection information of the input display data is increased, or the correction coefficient is limited to the maximum value itself or the detection information of the input display data. It is also effective to have various variations in how to make changes. As described above, according to the present invention, the temperature unevenness correction level can be appropriately changed according to the input display data signal, so that the temperature can be spread over the light emitting surface without greatly degrading the display quality such as brightness unevenness. There is an effect that it can be kept almost uniform.

  Next, a third embodiment of the present invention will be described. FIG. 11 is a graph showing an outer periphery temperature unevenness correction pattern according to the third embodiment. In order to facilitate understanding, the same notation as the graph showing the outer peripheral temperature unevenness correction pattern of the first embodiment shown in FIG. 5 is used. The previous embodiment shown in FIG. 5 represents a positive outer periphery temperature unevenness correction pattern, and correction display data is obtained by adding to the input display data. On the other hand, the graph of FIG. 11 represents a negative peripheral temperature unevenness correction pattern. As is apparent from the graph, the corrected display data can be obtained by subtracting the negative outer peripheral temperature unevenness correction pattern data indicated by diagonal lines from the input display data. This corrected display data has a higher gradation level near the outermost peripheral edge of the light emitting surface than the center of the panel. Accordingly, the light emitting element near the outermost peripheral edge of the light emitting surface emits extra light and generates extra heat accordingly, so that low temperature unevenness can be compensated.

  FIG. 12 is a graph showing a lower temperature unevenness correction pattern. Similar to the outer periphery temperature unevenness correction pattern shown in FIG. 11, this is a negative correction pattern. As shown in the graph, the correction display data is obtained by subtracting the correction pattern in the shaded area from the input display data. This corrected display data has a gradation level relatively higher than the center of the panel in the range of about 200 mm in the vicinity of the lowermost end of the light emitting surface. Accordingly, the light emitting element near the lowermost end of the light emitting surface emits strong light, and the amount of generated heat increases accordingly. The lower temperature unevenness can be corrected by the amount of increase in the heat generation amount.

  13 is a graph showing a negative combined temperature unevenness correction pattern obtained by combining the negative outer temperature unevenness correction pattern shown in FIG. 11 with the negative lower temperature unevenness correction pattern shown in FIG. In order to facilitate understanding, the same notation as the positive composite temperature unevenness correction pattern shown in FIG. 7 is used. As is apparent from the graph, the correction display data converted from the input display data by the negative composite temperature unevenness correction pattern has an increased gradation level in the main correction area 1 and can correct low-temperature unevenness in this area. is there. The main correction region 1 is a low temperature region located in a range of about 20 mm near the uppermost end and the lowermost end of the light emitting surface. The correction display data also has a slight increase in gradation level in the main correction area 2, and low temperature unevenness in this area can be corrected. The main correction region 2 exists with a width of about 200 mm in the vicinity of the lowermost end of the light emitting surface. Furthermore, the gradation level of the corrected display data is further increased at the portion where the main correction area 1 and the main correction area 2 overlap. This portion is substantially a portion obtained by synthesizing the outer periphery temperature unevenness correction pattern and the lower temperature unevenness correction pattern.

  Further, a fourth embodiment of the present invention will be described. FIG. 14 is a graph showing a temperature unevenness correction pattern according to the fourth embodiment. In order to facilitate understanding, the same notation as the graph showing the temperature unevenness correction pattern of the second embodiment shown in FIG. 9 is used. The previous embodiment shown in FIG. 9 represents a positive temperature unevenness correction pattern, and correction display data is obtained by adding to the input display data. On the other hand, the graph of FIG. 14 represents a negative temperature unevenness correction pattern. Four levels are displayed using the screen brightness as a parameter. When the screen brightness is bright, use the basic correction level. When the screen brightness is dark, the input display data is used as it is without correction. If the screen brightness is intermediate, use the intermediate correction level. Selection of such a correction level is obtained by multiplying the basic correction level by a correction coefficient that takes a numerical value of 0 to 1. The correction coefficient is determined according to the screen brightness. When the screen brightness is considerably bright, the correction coefficient is close to 1. When the screen brightness is considerably dark, the correction coefficient approaches zero. When the screen brightness is medium, the correction coefficient is in the vicinity of 0.5. When the panel is not used in a vertical position, the correction of the lower region can be performed with the correction coefficient set to zero, or the correction coefficient can be controlled according to the use inclination.

  FIG. 15 is a block diagram showing a configuration example of the organic EL display panel module shown in FIG. The module 1 includes a pixel array unit 100 in which pixel circuits (PXLC) 101 are arranged in an m × n matrix, a horizontal selector (HSEL) 103, a write scanner (WSCN) 104, a drive scanner (DSCN) 105, a horizontal selector. The signal lines DTL101 to DTL10n to which signals corresponding to the luminance information are selected and the scanning lines WSL101 to WSL10m selectively driven by the write scanner 104 and the scanning lines DSL101 to DSL10m selectively driven by the drive scanner 105 are included. . The pixel array unit 100 constitutes a light emitting surface, and the surface temperature distribution is uneven.

  FIG. 16 is a circuit diagram showing a configuration example of the pixel circuit shown in FIG. As shown in the figure, the pixel circuit 101 is basically composed of a p-channel thin film field effect transistor (hereinafter referred to as TFT). That is, the pixel circuit 101 includes a drive TFT 111, a switching TFT 112, a sampling TFT 115, an organic EL element 117, and a storage capacitor C111. The pixel circuit 101 having such a configuration is arranged at an intersection between the signal line DTL101 and the scanning lines WSL101 and DSL101. The signal line DTL101 is connected to the drain of the sampling TFT 115, the scanning line WSL101 is connected to the gate of the sampling TFT 115, and the other scanning line DSL101 is connected to the gate of the switching TFT 112.

  The drive TFT 111, the switching TFT 112, and the organic EL element 117 are connected in series between the power supply potential Vcc and the ground potential GND. That is, the source of the drive transistor 111 is connected to the power supply potential Vcc, while the cathode of the organic EL element (light emitting element) 117 is connected to the ground potential GND. In general, the organic EL element 117 is represented by a diode symbol because of its rectifying property. On the other hand, the sampling TFT 115 and the storage capacitor C111 are connected to the gate of the drive TFT111. The gate-source voltage of the drive TFT 111 is represented by Vgs.

  The operation of the pixel circuit 101 is as follows. First, when the scanning line WSL101 is in a selected state (here, low level) and a signal is applied to the signal line DTL101, the sampling TFT 115 is turned on and the signal is written into the storage capacitor C111. The signal potential written in the storage capacitor C111 becomes the gate potential of the drive transistor 111. Subsequently, when the scanning line WSL101 is in a non-selected state (here, high level), the signal line DTL101 and the drive TFT 111 are electrically disconnected, but the gate potential Vgs of the drive TFT 111 is stably held by the holding capacitor C111. . Subsequently, when another scanning line DSL101 is selected (here, at a low level), the switching TFT 112 becomes conductive, and a drive current flows through the TFT 111, TFT 112, and the light emitting element 117 from the power supply potential Vcc toward the ground potential GND. When the DSL 101 is in a non-selected state, the switching transistor 112 is turned off and the driving current does not flow. The switching TFT 112 is inserted to control the light emission time of the light emitting element 117.

  The current flowing through the TFT 111 and the light emitting element 117 has a value corresponding to the gate-source voltage Vgs of the TFT 111, and the light emitting element 117 continues to emit light with a luminance corresponding to the current value. As described above, the operation of selecting the scanning line WSL101 and transmitting the signal given to the signal line DTL101 to the inside of the pixel circuit 101 is referred to as “writing”. As described above, once a signal is written, the light emitting element 117 continues to emit light at a constant luminance until the next rewriting.

1 is a block diagram showing a first embodiment of the present invention. It is a schematic diagram with which it uses for operation | movement description of 1st Embodiment shown in FIG. FIG. 3 is a schematic diagram for explaining the operation of the first embodiment shown in FIG. 1. FIG. 3 is a schematic diagram for explaining the operation of the first embodiment shown in FIG. 1. FIG. 3 is a schematic diagram for explaining the operation of the first embodiment shown in FIG. 1. FIG. 3 is a schematic diagram for explaining the operation of the first embodiment shown in FIG. 1. FIG. 3 is a schematic diagram for explaining the operation of the first embodiment shown in FIG. 1. It is a block diagram which shows 2nd Embodiment of this invention. It is a graph with which it uses for operation | movement description of 2nd Embodiment shown in FIG. It is a table | surface diagram with which it uses for operation | movement description of 2nd Embodiment similarly shown in FIG. It is a graph with which it uses for operation | movement description of 3rd Embodiment. It is a graph similarly provided for operation | movement description of 3rd Embodiment. It is a schematic diagram for explaining the operation of the third embodiment. It is a graph with which it uses for operation | movement description of 4th Embodiment. It is a block diagram which shows the structural example of the display panel module shown in FIG. It is a circuit diagram which shows the structural example of the display panel module similarly similarly shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Display panel module, 2 ... Temperature unevenness correction pattern production | generation means, 3 ... Display data conversion circuit, 4 ... Display data information detection means, 5 ... Correction level control circuit

Claims (7)

An image display device comprising a module including a display panel, a display data conversion circuit, and a correction pattern generation means,
The display panel has a light emitting surface composed of pixels composed of light emitting elements, emits light according to display data, displays an image, and generates heat generated by each light emitting element and local deviation of heat dissipation. As a result, typical irregularities occur in the temperature distribution on the light emitting surface,
The correction pattern generation means generates correction pattern data representing a display pattern corresponding to the regular unevenness of the temperature distribution,
The display data conversion circuit converts display data input from the outside based on the generated correction pattern data, and thereby displays correction display data capable of correcting typical irregularities in the temperature distribution on the display. An image display device characterized in that unevenness in temperature distribution on the light emitting surface of the display panel is alleviated by supplying the light to each panel and displaying an image by causing each light emitting element to emit light with the corrected display data. The correction pattern generation means includes peripheral temperature unevenness correction pattern data for correcting a regular unevenness of a temperature distribution caused by a temperature drop due to heat conduction from an outer peripheral portion surrounding the central portion of the light emitting surface to an adjacent non-light emitting portion. Stored outer temperature unevenness correction pattern storage means;
A lower temperature unevenness correction pattern storage means storing lower temperature unevenness correction pattern data for correcting a regular unevenness of a temperature distribution generated by a temperature drop caused by cooling the lower portion of the light emitting surface by air convection;
The outer peripheral temperature unevenness correction pattern data and the lower temperature unevenness correction pattern data are combined, and thus combined correction pattern data capable of correcting a typical unevenness of the temperature distribution of the entire light emitting surface is supplied to the display data conversion circuit. The image display apparatus according to claim 1, further comprising a temperature unevenness correction pattern synthesizing unit. Display data information detecting means for detecting a frame gradation average value from display data representing a multi-gradation image input from the outside in units of frames;
A correction level control circuit for controlling a correction level of the correction pattern data generated by the temperature unevenness correction pattern generation means according to the frame gradation average value obtained from the display data information detection means. The image display device according to claim 1. Display data information detecting means for extracting the position of the object on the light emitting surface from the display data representing the image including the object input from the outside;
And a correction level control circuit for controlling a correction level of the correction pattern data generated by the temperature unevenness correction pattern generation unit in accordance with the position of the object obtained from the display data information detection unit. Item 2. The image display device according to Item 1. The light emitting surface of the display panel has a correction region that needs to be corrected at a lower temperature than others along the regular unevenness of the temperature distribution,
The correction pattern generation means generates correction pattern data representing a display pattern corresponding to the correction area,
The display data conversion circuit generates correction display data capable of correcting the unevenness of the temperature distribution by adding the generated correction pattern data to display data input from the outside. 1. The image display device according to 1. The light emitting surface of the display panel has a correction region that needs to be corrected at a lower temperature than the other regions along the regular unevenness of the temperature distribution,
The correction pattern generation means generates correction pattern data representing a display pattern corresponding to another area excluding the correction area,
The display data conversion circuit generates corrected display data capable of correcting the unevenness of the temperature distribution by subtracting the generated correction pattern data from externally input display data. 1. The image display device according to 1. It has a light emitting surface composed of a set of pixels consisting of light emitting elements, emits light according to display data, displays an image, and emits light due to the heat generated by each light emitting element and local deviation of its heat dissipation A temperature correction method for an image display device including a display panel having a typical unevenness in the temperature distribution of
A procedure for generating correction pattern data representing a display pattern corresponding to the typical unevenness of the temperature distribution;
A procedure for converting display data input from the outside based on the generated correction pattern data, and thereby supplying correction display data capable of correcting typical irregularities in the temperature distribution to the display panel. Done
A temperature correction method for an image display device, wherein unevenness in temperature distribution on a light emitting surface of the display panel is alleviated by causing each light emitting element to emit light with the corrected display data to display an image.

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