Patent Publication Number: US-2023140888-A1

Title: Signal Processing Apparatus, Signal Processing Method, And Display Apparatus

Description:
TECHNICAL FIELD 
     The present technology relates to a signal processing apparatus, a signal processing method, and a display apparatus, and in particular, to a signal processing apparatus, a signal processing method, and a display apparatus that can reduce the effect of deterioration in element of a display panel. 
     BACKGROUND ART 
     In recent years, self-luminous display apparatuses such as OLED display apparatuses are on the verge of becoming the mainstream of display devices configured to display video. For example, PTL 1 discloses a technology for enhancing the luminance of a display panel as a technology relating to display apparatuses such as self-luminous display apparatuses. 
     CITATION LIST 
     Patent Literature 
     [PTL 1] 
     Japanese Patent Laid-open No. 2015-94795 
     SUMMARY 
     Technical Problem 
     Incidentally, in respect of display apparatuses, it is demanded to reduce, in enhancing the luminance of the display panel, the effect of deterioration in element of the display panel. 
     The present technology has been made in view of such a circumstance and makes it possible to reduce the effect of deterioration in element of a display panel. 
     Solution to Problem 
     According to an aspect of the present technology, there is provided a signal processing apparatus including a signal processing unit configured to acquire, in changing a video signal from a low luminance display signal to a high luminance display signal by luminance enhancement, an accumulated load increase amount obtained by measuring and accumulating amounts of increase in load on a display panel caused by luminance enhancement, and adaptively control, in reference to the accumulated load increase amount acquired, a first gain for improving luminance of the video signal, according to a degree of effect of deterioration in element of the display panel. 
     According to an aspect of the present technology, there is provided a signal processing method including, by a signal processing apparatus, acquiring, in changing a video signal from a low luminance display signal to a high luminance display signal by luminance enhancement, an accumulated load increase amount obtained by measuring and accumulating amounts of increase in load on a display panel caused by luminance enhancement, and adaptively controlling, in reference to the accumulated load increase amount acquired, a first gain for improving luminance of the video signal, according to a degree of effect of deterioration in element of the display panel. 
     In the signal processing apparatus and the signal processing method according to the aspects of the present technology, in changing a video signal from a low luminance display signal to a high luminance display signal by luminance enhancement, an accumulated load increase amount obtained by measuring and accumulating amounts of increase in load on the display panel caused by luminance enhancement is acquired, and in reference to the accumulated load increase amount acquired, a first gain for improving luminance of the video signal is adaptively controlled according to a degree of effect of deterioration in element of the display panel. 
     According to an aspect of the present technology, there is provided a display apparatus including a panel unit including a display panel, and a signal processing unit configured to process a video signal, in which the signal processing unit is configured to acquire, in changing the video signal from a low luminance display signal to a high luminance display signal by luminance enhancement, an accumulated load increase amount obtained by measuring and accumulating amounts of increase in load on the display panel caused by luminance enhancement, and adaptively control, in reference to the accumulated load increase amount acquired, a first gain for improving luminance of the video signal, according to a degree of effect of deterioration in element of the display panel. 
     In the display apparatus according to the aspect of the present technology, in changing a video signal from a low luminance display signal to a high luminance display signal by luminance enhancement, an accumulated load increase amount obtained by measuring and accumulating amounts of increase in load on the display panel caused by luminance enhancement is acquired, and in reference to the accumulated load increase amount acquired, a first gain for improving luminance of the video signal is adaptively controlled according to a degree of effect of deterioration in element of the display panel. 
     The signal processing apparatus and the display apparatus according to the aspects of the present technology may be independent apparatuses or internal blocks of a single apparatus. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    depicts diagrams illustrating exemplary luminance enhancement processing. 
         FIG.  2    is a block diagram illustrating a configuration example of a display apparatus of an embodiment to which the present technology is applied. 
         FIG.  3    is a block diagram illustrating a detailed configuration example of a signal processing unit. 
         FIG.  4    is a diagram illustrating an example of how a load increase amount measuring/accumulating unit measures/accumulates load increase amounts. 
         FIG.  5    is a diagram illustrating a first exemplary accumulated additional value based on a load increase amount. 
         FIG.  6    is a diagram illustrating a second exemplary accumulated additional value based on a load increase amount. 
         FIG.  7    is a diagram illustrating a configuration example including a single temperature sensor provided on a panel unit. 
         FIG.  8    is a diagram illustrating a configuration example including multiple temperature sensors provided on the panel unit. 
         FIG.  9    is a diagram illustrating an example of how to set a gain relative to an accumulated load increase amount. 
         FIG.  10    is a flowchart illustrating the flow of luminance improvement gain control processing. 
     
    
    
     DESCRIPTION OF EMBODIMENT 
     1. Embodiment of Present Technology 
     Technologies for enhancing the luminance of display apparatuses such as OLED display apparatuses include the technology that detects a video signal being switched from a low luminance display signal (low luminance signal) to a high luminance display signal (high luminance signal) and controls the luminance improvement gain in reference to the increasing integrated value (see PTL 1 described above). 
       FIG.  1    illustrates exemplary luminance enhancement processing to which such a luminance enhancement technology is applied. In  FIG.  1   , A illustrates a relation between an input video signal and an integrated value by a thick line L 11  and a thick line L 12  on the same time axis. 
     In  FIG.  1   , B illustrates a relation between a gain by which an input video signal is multiplied and an integrated value by a thick line L 13  and a thick line L 14  on the same time axis. In  FIG.  1   , C illustrates a relation between an output video signal obtained by multiplying an input video signal by a gain and an integrated value by a thick line L 15  and a thick line L 16  on the same time axis. 
     In a case where luminance enhancement processing illustrated in  FIG.  1    is used, each period of luminance improvement for a high luminance signal can be controlled. Even when each period is short, however, the accumulated luminance improvement time is increased along with the continuous use of the display panel over a long period of time. As a result, there arises a problem in that burn-in or the like occurs due to element deterioration in the display panel of the display apparatus. 
     The present technology proposes a technique for solving a problem in terms of the long-term reliability of a display panel such as burn-in caused by a problematic element deterioration that occurs in enhancing the luminance of the display panel as described above. Now, with reference to the drawings, an embodiment of the present technology is described. 
     (Apparatus Configuration) 
       FIG.  2    illustrates a configuration example of a display apparatus of an embodiment to which the present technology is applied. 
     A display apparatus  1  is a self-luminous display apparatus such as an OLED display apparatus including an OLED display panel. The display apparatus  1  is configured as a television receiver or the like. 
     In  FIG.  2   , the display apparatus  1  includes a signal input unit  110 , a signal processing unit  111 , a panel driving unit  112 , and a panel unit  113 . 
     The signal input unit  110  includes a tuner connected to an antenna, a communication module that can be connected to the Internet or other communication networks, an input interface conforming to predetermined standards, or the like. 
     The signal input unit  110  supplies, to the signal processing unit  111 , video signals of various types of content such as broadcasting content that is transmitted by terrestrial broadcasting or satellite broadcasting, communication content that is delivered by streaming via the Internet or other communication networks, or recorded content recorded on a recoding medium such as an optical disc or a semiconductor memory or a recorder. 
     The signal processing unit  111  performs video signal processing on a video signal of content supplied from the signal input unit  110  and supplies the thus obtained video signal to the panel driving unit  112 . In the video signal processing, luminance enhancement processing for changing a video signal from a low luminance display signal (low luminance signal) to a high luminance display signal (high luminance signal) or the like is carried out. 
     The panel driving unit  112  drives the panel unit  113  according to a video signal supplied from the signal processing unit  111 . 
     The panel unit  113  includes a display panel such as an OLED display panel. The panel unit  113  is driven by the panel driving unit  112  to display video based on video signals of various types of content. 
     An OLED display panel is a display panel in which pixels including OLED elements that are self-luminous elements are two-dimensionally arranged. An OLED (Organic Light Emitting Diode) is a light-emitting element having a structure in which an organic luminescent material is sandwiched between a cathode and an anode and forms each of pixels (display pixels) two-dimensionally arranged in an OLED display panel. 
     In a WRGB OLED panel, each pixel (display pixel) includes four sub pixels of white (W), red (R), green (G), and blue (B). In an RGB OLED panel, each pixel (display pixel) includes three sub pixels of red (R), green (G), and blue (B). 
     Note that, in the configuration illustrated in  FIG.  2   , for the sake of simple description, the bare minimum constituent units are illustrated, but other circuits or devices such as a sound signal processing circuit configured to process sound signals or a speaker configured to output sound based on sound signals may also be included. 
       FIG.  3    illustrates a detailed configuration example of the signal processing unit  111  of  FIG.  2   . 
     In  FIG.  3   , the signal processing unit  111  includes a luminance improvement reference gain calculating unit  131 , a load increase amount measuring/accumulating unit  132 , a nonvolatile memory  133 , a luminance improvement gain calculating unit  134 , an addition unit  135 , and a multiplication unit  136 . 
     In the signal processing unit  111 , an input video signal from the signal input unit  110  is supplied to each of the luminance improvement reference gain calculating unit  131 , the load increase amount measuring/accumulating unit  132 , and the multiplication unit  136 . 
     The luminance improvement reference gain calculating unit  131  performs luminance improvement reference gain calculation processing according to a video signal input thereto and supplies the thus obtained luminance improvement reference gain to the luminance improvement gain calculating unit  134 . A luminance improvement reference gain is a gain that is used as a reference for luminance improvement gain calculation. 
     The load increase amount measuring/accumulating unit  132  performs accumulated additional value calculation processing and accumulation processing according to a video signal input thereto and a fold improvement in luminance and supplies the thus obtained accumulated value of accumulated load increase amounts to the luminance improvement gain calculating unit  134 . As a fold improvement in luminance, a fold improvement in luminance based on a gain by which an input video signal is multiplied is fed back to be input. 
     The details of accumulated additional value calculation processing and accumulation processing are described later with reference to  FIG.  4    to  FIG.  6   . To store accumulated value data in performing accumulation processing, the nonvolatile memory  133  such as an EEPROM (Electrically Erasable Programmable Read Only Memory) is provided. 
     Further, the load increase amount measuring/accumulating unit  132  can perform accumulated additional value calculation processing by taking into account at least one of the measurement result of the surface temperature of the display panel and the measurement result of a current flowing through the display panel, which are supplied from the panel driving unit  112 . 
     The luminance improvement gain calculating unit  134  receives a luminance improvement reference gain supplied from the luminance improvement reference gain calculating unit  131  and the accumulated value of accumulated load increase amounts supplied from the load increase amount measuring/accumulating unit  132 . 
     The luminance improvement gain calculating unit  134  performs luminance improvement gain calculation processing in reference to the luminance improvement reference gain and the accumulated value of accumulated load increase amounts and supplies the thus obtained luminance improvement gain to the addition unit  135 . 
     In the luminance improvement gain calculation processing, as a luminance improvement gain, a value is calculated by multiplying a luminance improvement reference gain by a gain linked to the accumulated value of accumulated load increase amounts (hereinafter referred to as an “accumulated load increase amount-linked gain”). The details of luminance improvement gain calculation processing are described later with reference to  FIG.  9   . 
     The addition unit  135  adds a luminance improvement gain from the luminance improvement gain calculating unit  134  and a normal-time gain together and supplies the thus obtained luminance enhancement gain to the multiplication unit  136 . 
     A normal-time gain is a gain by which an input video signal is multiplied and is a gain for changing an input video signal to a high luminance display signal. For example, as a normal-time gain, a gain with which luminance enhancement can always be carried out without causing problematic element deterioration in the usage period of the display panel is set. 
     Here, an additional luminance improvement gain is added to a normal-time gain to further enhance the luminance of an input video signal. The additional luminance improvement gain is adaptively controlled according to the measurement result of an accumulated load increase amount, the measurement result of the surface temperature of the display panel, and the measurement result of a current load on the display panel. 
     The multiplication unit  136  multiplies an input video signal by a luminance enhancement gain from the addition unit  135  and supplies the thus obtained output video signal to the panel driving unit  112 . 
     In  FIG.  3   , the panel driving unit  112  can include a panel temperature measuring unit  151  and a panel current measuring unit  152 . 
     The panel temperature measuring unit  151  includes temperature sensors or the like provided on the panel unit  113 . The panel temperature measuring unit  151  measures the surface temperature of the display panel and supplies the measurement result to the load increase amount measuring/accumulating unit  132  of the signal processing unit  111 . Configuration examples of the temperature sensors are described later with reference to  FIG.  7    and  FIG.  8   . 
     The panel current measuring unit  152  includes a current sensor or the like provided on the panel unit  113 . The panel current measuring unit  152  measures a current applied to the display panel and supplies the measurement result to the load increase amount measuring/accumulating unit  132  of the signal processing unit  111 . 
     Note that, the configuration of the signal processing unit  111  illustrated in  FIG.  3    is an example, and the bare minimum constituent units thereof can form a configuration that does not use measurement results from the panel temperature measuring unit  151  and the panel current measuring unit  152 . Even with such a configuration, the amounts of increase in load on the display panel caused by luminance enhancement can be accumulated and the additional luminance improvement gain can be controlled to prevent the elements from being deteriorated too much. Further, with the configuration that uses measurement results from the panel temperature measuring unit  151  and the panel current measuring unit  152 , the accuracy can be more increased. 
     (Calculation of Luminance Improvement Reference Gain) 
     How the luminance improvement reference gain calculating unit  131  calculates a luminance improvement reference gain is not limited to anything specific, and the luminance improvement reference gain calculating unit  131  may calculate a fixed gain or a gain that changes according to some information, for example. 
     However, with an additional luminance improvement gain, a current load is increased to achieve luminance enhancement, and the effect of display panel burn-in is thus large; accordingly, the processing of limiting the length of time of performing luminance enhancement processing on the same place (region) is desirably carried out as in luminance enhancement processing illustrated in  FIG.  1    to which the luminance enhancement technology is applied. 
     (Measurement/Accumulation of Load Increase Amounts) 
     As described above in the abovementioned problem, mere measurement of a luminance improvement period causes problematic deterioration in element of a display panel, since there is no limit on the accumulated luminance improvement time that is increased along with the continuous use of the display panel over a long period of time. Accordingly, there is a need to accumulate the amounts of increase in load caused by luminance enhancement processing and perform feedback control for the luminance improvement gain to prevent the elements from being deteriorated to a level greater than a certain level due to the processing. 
       FIG.  4    illustrates an example of how the load increase amount measuring/accumulating unit  132  measures load increase amounts. In  FIG.  4   , the load increase amount measuring/accumulating unit  132  includes an accumulated additional value calculating unit  141  and an accumulation processing unit  142 . 
     The accumulated additional value calculating unit  141  receives an input video signal and a fold improvement in luminance. The accumulated additional value calculating unit  141  calculates an additional value for accumulation processing based on an increase in load caused by luminance enhancement processing. 
     In the accumulated additional value calculation processing, an accumulated additional value can be correlated with an element deterioration amount or an accumulated additional value can be correlated with a luminance improvement time. 
       FIG.  5    in which the horizontal axis indicates load increase amounts and the vertical axis indicates accumulated additional values illustrates, by a thick line L 21 , a relation in a case where an accumulated additional value is correlated with an element deterioration amount. In  FIG.  5   , the thick line L 21  has such a relation that as the load increase amount is increased, the accumulated additional value is increased with a predetermined gradient, and the higher the load is, the larger the additional value is. That is, in this example, a larger additional value is calculated for a higher load to make a correlation with an element deterioration amount. 
       FIG.  6    in which the horizontal axis indicates load increase amounts and the vertical axis indicates accumulated additional values illustrates, by a thick line L 31 , a relation in a case where an accumulated additional value is correlated with a luminance improvement time. In  FIG.  6   , the thick line L 31  has such a relation that the accumulated additional value has a constant value according to an increase in load increase amount, and the additional value is constant irrespective of the load. That is, in this example, a constant additional value is calculated to measure a length of time in which luminance enhancement processing has been carried out. 
     The accumulation processing unit  142  adds together an additional value of each image frame calculated by accumulated additional value calculation processing, to thereby calculate the accumulated value of load increase amounts (accumulated load increase amount). Further, the accumulation processing unit  142  writes or reads accumulated value data to or from the nonvolatile memory  133  such as an EEPROM to keep the accumulated value when the display apparatus  1  is powered off. 
     The accumulation processing unit  142  carries out accumulation processing on each predetermined region on the screen of the display panel to calculate the accumulated value of each predetermined region in question, thereby making it possible to determine how long luminance enhancement processing has been carried out on the same place (region). Then, the luminance improvement gain calculating unit  134  can control the additional luminance improvement gain in reference to the accumulated load increase amount. 
     Note that, as a region on the screen of the display panel, for example, a region obtained by dividing the region of the entire screen into multiple regions having predetermined longitudinal and lateral dimensions can be used. Specifically, for example, a region corresponding to a divided region A of  FIG.  8    described later can be used. 
     (Measurement of Panel Temperature) 
     The load increase amount measuring/accumulating unit  132  performs load prediction by signal processing without using information regarding deterioration characteristics that change depending on temperature. Thus, the accuracy can be improved by carrying out video load prediction by signal processing or measuring an actual surface temperature of the display panel by temperature sensors or the like and taking information regarding the thus obtained temperature into account for the accumulated additional value of each predetermined region on the screen of the display panel. 
     Only one temperature sensor may be installed on the panel unit  113  to obtain supplementary information for load prediction by signal processing or multiple temperature sensors may be installed on the panel unit  113  for the purpose of improving the accuracy of supplementary information or directly measuring a temperature without performing load prediction by signal processing. 
       FIG.  7    illustrates a configuration example including a single temperature sensor provided on the panel unit  113 . In  FIG.  7   , a temperature sensor  171  is installed at a location corresponding to the substantially center portion of the screen of the display panel and measures the surface temperature of the display panel. Note that, the temperature sensor  171  may be installed at a location other than the location corresponding to the substantially center portion of the screen of the display panel. 
       FIG.  8    illustrates a configuration example including multiple temperature sensors provided on the panel unit  113 .  FIG.  8    illustrates the example in which the region of the entire screen of the display panel is divided into 4×9 regions that are the same in longitudinal and lateral dimensions and the temperature sensor  171  is installed in each divided region. Note that, for the convenience of description, on the screen of the display panel, the dashed lines indicating the boundaries between the divided regions are illustrated. 
     In  FIG.  8   , the numbers corresponding to the longitudinal direction and lateral direction of the divided region A are described in an upper-left divided region A 11  and a lower-right divided region Aij on the screen of the display panel. Further, the numbers corresponding to the longitudinal direction and lateral direction of the temperature sensor  171  are described in an upper-left temperature sensor  171 - 11  and a lower-right temperature sensor  171 -ij. 
     However, in those representations, i indicates the number in the longitudinal direction, and j indicates the number in the lateral direction. In other words, although  FIG.  8    illustrates the example in which the screen of the display panel is divided into the 4×9 divided regions, the screen of the display panel can be divided into i×j (i and j: integer of 1 or more) divided regions A, and the number of the divided regions A in which the temperature sensor  171  is installed is optionally determined. 
     In  FIG.  8   , the temperature sensor  171 - 11  measures the surface temperature of the divided region A 11  of the entire screen of the display panel. The temperature sensor  171 -ij other than the temperature sensor  171 - 11  also measures the surface temperature of the divided region Aij corresponding to the installation location, the description of which is omitted to avoid repetition. 
     The temperature sensor  171  of  FIG.  7    and the temperature sensors  171 - 11  to  171 -ij of  FIG.  8    correspond to the panel temperature measuring unit  151  of  FIG.  3   . In the case where the multiple temperature sensors  171 - 11  to  171 -ij are installed, as compared to the case where the single temperature sensor  171  is installed, the surface temperature of the display panel can be measured more accurately. 
     (Measurement of Current Load) 
     An improvement in accuracy of the measurement of a load increase amount can be expected by measurement of a current actually flowing through the display panel by a current sensor or the like in addition to load prediction by signal processing. For example, the current sensor can be provided on the display panel itself or a power supply board configured to generate a voltage for driving the display panel. 
     (Calculation of Luminance Improvement Gain) 
     The luminance improvement gain calculating unit  134  can reduce, when luminance enhancement processing has been carried out over a long period of time and the accumulated load increase amount is thus high, the luminance improvement gain, to thereby reduce the effect of element deterioration caused by luminance enhancement processing in the usage period. 
     That is, the luminance improvement gain calculating unit  134  performs control for reducing a luminance improvement gain when the accumulated value of load increase amounts exceeds a predetermined value in a case where luminance enhancement processing has been carried out over a period longer than a predetermined period. The luminance improvement gain calculating unit  134  sets a value obtained by multiplying a luminance improvement reference gain by an accumulated load increase amount-linked gain, as an ultimate luminance improvement gain. 
       FIG.  9    illustrates how to set a gain relative to an accumulated load increase amount. In  FIG.  9   , the horizontal axis indicates accumulated value, and the vertical axis indicates accumulated load increase amount-linked gain. 
     In  FIG.  9   , the gain based on the accumulated load increase amount is indicated by a thick line L 41  including the straight line downward to the right. The accumulated load increase amount-linked gain is maintained at 100% until the accumulated value reaches a predetermined value and gradually decreased with a predetermined gradient after the accumulated value exceeds the predetermined value. The accumulated load increase amount-linked gain is maintained at 0% after reaching 0%. 
     For example, the luminance improvement gain calculating unit  134  can control, with an accumulated load increase amount-linked gain, a luminance improvement gain for the entire screen according to the maximum value of the accumulated value of each predetermined region on the screen of the display panel. Further, the luminance improvement gain calculating unit  134  can control, with an accumulated load increase amount-linked gain, a luminance improvement gain for each predetermined region on the screen of the display panel according to the accumulated value of each predetermined region in question. 
     Note that, also in this case, a region on the screen of the display panel can be, for example, a region obtained by dividing the region of the entire screen into multiple regions having predetermined longitudinal and lateral dimensions. Specifically, a region corresponding to the divided region A of  FIG.  8    described above can be used, for example. 
     (Adaptive Gain Control) 
       FIG.  10    is a flowchart illustrating the flow of luminance improvement gain control processing that is carried out by the signal processing unit  111 . 
     In Step S 11 , the luminance improvement gain calculating unit  134  acquires an accumulated load increase amount from the load increase amount measuring/accumulating unit  132 . 
     The accumulated load increase amount is the accumulated value of load increase amounts obtained by measuring and accumulating the amounts of increase in load on the display panel caused by luminance enhancement. The accumulated load increase amount may take into account supplementary information such as the measurement result of the surface temperature of the display panel or the measurement result of a current flowing through the display panel. 
     In Step S 12 , the luminance improvement gain calculating unit  134  adaptively controls, in reference to the acquired accumulated load increase amount, a luminance improvement gain according to the degree of effect of deterioration in element of the display panel. 
     For example, the luminance improvement gain calculating unit  134  performs control for reducing a luminance improvement gain when luminance enhancement processing has been carried out over a long period of time and the accumulated load increase amount is thus high and sets a value obtained by multiplying a luminance improvement reference gain by an accumulated load increase amount-linked gain, as an ultimate luminance improvement gain. 
     As described above, in changing a video signal from a low luminance display signal to a high luminance display signal by luminance enhancement, the signal processing unit  111  adaptively controls, in reference to an accumulated load increase amount obtained by measuring and accumulating the amounts of increase in load on the display panel, a luminance improvement gain according to the degree of effect of an element deterioration. 
     This can solve the problem in terms of the long-term reliability of a display panel such as burn-in caused by problematic element deterioration that occurs in enhancing the luminance of the display panel and can thereby reduce the effect of deterioration in element of the display panel. In the case of an OLED display panel, the elements of the display panel are the OLED elements of the two-dimensionally arranged pixels, for example. 
     2. Modified Example 
     In the above description, the signal processing unit  111  is the component of the display apparatus  1 , but the signal processing unit  111  may be regarded as a single apparatus, that is, a signal processing apparatus. 
     In the case exemplified above, the display apparatus  1  is the television receiver, but the display apparatus  1  is not limited thereto and may be equipment such as display equipment. Examples of the display equipment include medical monitors, broadcast monitors, and digital signage displays. 
     Further, the display apparatus  1  may be used as a display unit for a PC (Personal Computer), a tablet device, a smartphone, a cell phone, a game console, a head-mounted display, an in-vehicle device such as a car navigation system or a rear-seat monitor, or a wearable device such as a wristwatch or a glass device. 
     In the above description, the OLED display apparatus including the OLED display panel has been exemplified as the display apparatus  1 , but the present technology is also applicable to display apparatuses such as other self-luminous display apparatuses including self-luminous display panels. 
     In the case described above, the pixels two-dimensionally arranged on (the display panel of) the panel unit  113  each include the four sub pixels of white (W), red (R), green (G), and blue (B), but the colors of the sub pixels are not limited to those. For example, in each pixel, instead of the white (W) sub pixel, a sub pixel of another color as high in luminosity factor as white (W) may be used. 
     Note that, herein, “OLED” may be replaced with “organic EL (Electro Luminescence).” For example, it can be said that the OLED display apparatus is an organic EL display apparatus. Further, “video” may be replaced with “image” since video includes multiple image frames. 
     Note that, the embodiment of the present technology is not limited to the embodiment described above, and various modifications can be made within the scope of the gist of the present technology. 
     Further, the effects described herein are only exemplary and not limitative, and other effects may be provided. 
     Note that, the present technology can take the following configurations. 
     (1) 
     A signal processing apparatus including: 
     a signal processing unit configured to
         acquire, in changing a video signal from a low luminance display signal to a high luminance display signal by luminance enhancement, an accumulated load increase amount obtained by measuring and accumulating amounts of increase in load on a display panel caused by luminance enhancement, and   adaptively control, in reference to the accumulated load increase amount acquired, a first gain for improving luminance of the video signal, according to a degree of effect of deterioration in element of the display panel.       

     (2) 
     The signal processing apparatus according to Item (1), in which the signal processing unit acquires the accumulated load increase amount in which information regarding a surface temperature of the display panel is taken into account. 
     (3) 
     The signal processing apparatus according to Item (1) or (2), in which the signal processing unit acquires the accumulated load increase amount in which information regarding a current flowing through the display panel is taken into account. 
     (4) 
     The signal processing apparatus according to any one of Items (1) to (3), in which the signal processing unit additionally adds the first gain to a second gain that is used for luminance enhancement, to thereby enhance the luminance of the video signal. 
     (5) 
     The signal processing apparatus according to Item (4), in which the signal processing unit uses, as the first gain, a value based on a third gain linked to the accumulated load increase amount. 
     (6) 
     The signal processing apparatus according to Item (5), in which the signal processing unit uses, as the first gain, a value obtained by multiplying the third gain by a fourth gain that is used as a reference for luminance improvement. 
     (7) 
     The signal processing apparatus according to any one of Items (1) to (6), in which 
     the signal processing unit is configured to
         calculate, according to the load that is increased due to luminance enhancement, an additional value for accumulation, and   add together the additional value calculated of each image frame to calculate an accumulated value of load increase amounts.       

     (8) 
     The signal processing apparatus according to Item (7), in which the signal processing unit calculates a larger additional value for a higher load to make a correlation with an element deterioration amount. 
     (9) 
     The signal processing apparatus according to Item (7), in which the signal processing unit calculates a constant additional value to measure a length of time in which luminance enhancement has been carried out. 
     (10) 
     The signal processing apparatus according to any one of Items (7) to (9), further including: 
     a memory configured to store data regarding the accumulated value. 
     (11) 
     The signal processing apparatus according to any one of Items (7) to (10), in which the signal processing unit calculates the accumulated value of load increase amounts of each of predetermined regions on a screen of the display panel. 
     (12) 
     The signal processing apparatus according to any one of Items (1) to (11), in which the signal processing unit performs control for reducing the first gain when an accumulated value of load increase amounts exceeds a predetermined value in a case where luminance enhancement has been carried out over a period longer than a predetermined period. 
     (13) 
     The signal processing apparatus according to Item (12), in which the signal processing unit controls, according to a maximum value of the accumulated value of each of predetermined regions on a screen of the display panel, the first gain for an entirety of the screen. 
     (14) 
     The signal processing apparatus according to Item (12), in which the signal processing unit controls, according to the accumulated value of each of predetermined regions on a screen of the display panel, the first gain for each of the predetermined regions. 
     (15) 
     The signal processing apparatus according to Item (2), in which the display panel is provided with one or multiple temperature sensors configured to measure the surface temperature. 
     (16) 
     A signal processing method including: 
     by a signal processing apparatus, 
     acquiring, in changing a video signal from a low luminance display signal to a high luminance display signal by luminance enhancement, an accumulated load increase amount obtained by measuring and accumulating amounts of increase in load on a display panel caused by luminance enhancement; and 
     adaptively controlling, in reference to the accumulated load increase amount acquired, a first gain for improving luminance of the video signal, according to a degree of effect of deterioration in element of the display panel. 
     (17) 
     A display apparatus including: 
     a signal processing unit configured to process a video signal; and 
     a panel unit including a display panel configured to display video based on the video signal, in which 
     the signal processing unit is configured to
         acquire, in changing the video signal from a low luminance display signal to a high luminance display signal by luminance enhancement, an accumulated load increase amount obtained by measuring and accumulating amounts of increase in load on the display panel caused by luminance enhancement, and   adaptively control, in reference to the accumulated load increase amount acquired, a first gain for improving luminance of the video signal, according to a degree of effect of deterioration in element of the display panel.       

     (18) 
     The display apparatus according to Item (17), in which the panel unit includes an OLED display panel. 
     REFERENCE SIGNS LIST 
     
         
         
           
               1 : Display apparatus 
               110 : Signal input unit 
               111 : Signal processing unit 
               112 : Panel driving unit 
               113 : Panel unit 
               131 : Luminance improvement reference gain 
             calculating unit 
               132 : Load increase amount measuring/accumulating 
             unit 
               133 : Nonvolatile memory 
               134 : Luminance improvement gain calculating unit 
               135 : Addition unit 
               136 : Multiplication unit 
               141 : Accumulated additional value calculating unit 
               142 : Accumulation processing unit 
               151 : Panel temperature measuring unit 
               152 : Panel current measuring unit 
               171 : Temperature sensor