JP2007079200A - Display apparatus and display method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display apparatus and a display method for fixing relative luminance differences with time between a bright image display part and a dark image display part by controlling the drive of respective light emitting elements. <P>SOLUTION: In the display apparatus and the display method, the display apparatus is provided with a plurality of light emitting elements 13 arrayed between a supporting substrate 11 and a counter substrate 12, a plurality of light receiving elements 19 each of which is arranged between the light emitting elements 13 on the surface side of the counter substrate 12 to detect and photoelectrically convert leaked light from the light emitting elements 13, and a control part 20 for controlling the drive of respective light emitting elements 13 on the basis of input signals to the light emitting elements 13 and output signals from the light receiving elements 19 so that the relative luminance differences of respective light emitting elements 13 with time are fixed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a display device and a display method, and more particularly, to a display device and a display method including self-luminous elements such as organic electroluminescent elements (organic EL elements).

  Conventionally, display devices (displays) using self-luminous elements such as light emitting diodes (LEDs), laser diodes (LD), organic EL elements, and phosphors have been developed. In this type of display device, generally, a plurality of self-luminous elements are arranged in a matrix to form a screen portion (display panel), and each element is selectively made to emit light according to a video signal, thereby displaying a video. Done. As a display medium, a display plays a major role in our daily life, such as a television receiver, a computer monitor, and a portable information terminal. With the development of the Internet, the importance of displays as human interfaces is increasing. There is a demand for high-resolution, high-speed displays that are easy on the eyes, easy to see on a high-definition screen, and that the video can be clearly and clearly displayed without delay.

  A display device using a self-light-emitting element has an advantage that a backlight is unnecessary compared with a non-self-light-emitting display device such as a liquid crystal display (LCD). However, as a self-luminous display device, a display device using a phosphor such as a cathode ray tube (CRT) or a plasma display panel (PDP) and an organic EL display device has a long still image. It is known to cause a seizure phenomenon by time display.

  Therefore, various devices and the like that reduce seizure are used. In conventional burn-in reduction devices, polarity reversal such as reversal of luminance (black / white reversal) or complementary color reversal between a character information display unit such as a clock display unit and its background portion is performed several times within a certain period. There is one that reduces seizure by providing a period for performing (Prior Art 1).

  Another method is to display a long-term still image at a certain location by shifting the display image of character information, etc. slowly and vertically up and down at a speed that cannot be visually recognized. There is something to prevent (Prior Art 2).

  Furthermore, by setting a screen saver or the like, if a still image of a certain period or longer is displayed, a method of displaying an arbitrary moving image from the still image, or an extreme method, a still image is displayed for a certain period of time. In such a case, a technique of bringing the display itself down as a whole system is also used (Prior Art 3).

  However, the conventional technology as described above is not satisfactory as an information display medium. For example, in the case of natural image information that displays a landscape image or the like, in the case of providing a still image, a technique such as the prior art 1 that performs polarity reversal does not allow a pure natural image to be displayed still and gives a sense of incongruity. End up.

  Further, in the conventional technique 2 in which the display image is shifted up, down, left, and right by a certain amount, since the amount that can be shifted is too small, a significant reduction in image sticking cannot be expected. On the other hand, there is a problem in that the moving part itself is gradually burned by the shift, and the stationary display character information itself gradually loses its clarity.

  In addition, when using information such as time display guidance, which is often used when using public institutions as a means of transportation, and sequential waiting time guidance progress guidance displayed at hospitals, city halls, etc., always use still images. In other words, it is not possible to use the technique as in the prior art 3.

  In the above-described CRT, PDP, and organic EL display device, it has been found that the higher the luminance, the more easily the phosphor or the organic EL element is deteriorated, and the still image is burned.

  Therefore, for example, in CRT and PDP, a color level for determining whether the signal level for each color of R (red), G (green), and B (blue) of a still image is higher or lower than a predetermined threshold level set in advance. A color level determining unit that includes a determination unit and a color level setting unit that individually sets a signal level of a display output signal for each color, and the still image is continuously displayed for a predetermined time or more. There has been reported a display burn-in prevention device that determines a color portion higher than a threshold level as a cause of burn-in and sets the signal level so that the color level setting unit lowers it in stages (see, for example, Patent Document 1). .

JP 2001-228847 A

  However, in actuality, even in a dark image display portion having a low luminance, the self-luminous element is displayed with a low luminance, so that burn-in occurs. For this reason, in order to reduce burn-in, if only the brightness of a bright still image is controlled and the brightness is lowered as described above, the vividness is reduced by comparing and recognizing with the surrounding dark image display unit, and the uncomfortable feeling is felt. It is something to remember. Therefore, it is considered to control the luminance of a dark still image and decrease the luminance at the same rate as that of a bright still image. However, in reality, the luminance decreases due to deterioration of the bright display element and the dark display element, respectively. For this reason, it is difficult to make the relative luminance difference over time constant between the bright image display unit and the dark image display unit.

  Therefore, the present invention has an object to provide a display device and a display method for controlling the driving of each light emitting element 13 so that the relative luminance difference over time between a bright image display unit and a dark image display unit is made constant. .

  In order to achieve such an object, a display device of the present invention is arranged between a plurality of light emitting elements arranged between a pair of substrates and a light emitting element of one of the pair of substrates, and emits light. Based on the light receiving element that detects and leaks light from the element and performs photoelectric conversion, and based on the input signal to the light emitting element and the output signal from the light receiving element, each light emitting element has a constant relative luminance difference over time. And a control unit that controls driving of the light emitting element.

  According to such a display device, since the drive of the light emitting element is controlled so that the relative luminance difference with time of each light emitting element becomes constant, the amount of luminance decrease due to deterioration of each light emitting element becomes constant. It is corrected. Thereby, brightness control for preventing burn-in can be performed with high controllability, and contrast is maintained between the bright image display unit and the dark image display unit.

  Further, the display method of the present invention detects the leakage light of each light emitting element by the light receiving element, and based on the input signal to the light emitting element and the output signal photoelectrically converted by the light receiving element, The driving of each light emitting element is controlled so that the luminance difference is constant.

  According to such a display method, since the drive of the light emitting element is controlled so that the relative luminance difference with time of each light emitting element becomes constant, the amount of luminance decrease due to deterioration of each light emitting element becomes constant. It is corrected. Thereby, brightness control for preventing burn-in can be performed with high controllability, and contrast is maintained between the bright image display unit and the dark image display unit.

  As described above, according to the display device and the display method of the present invention, brightness control for preventing burn-in can be performed with good controllability, and contrast between the bright image display unit and the dark image display unit is maintained over time. Therefore, even when a still image is displayed for a long time, image sticking can be reduced without causing a sense of incongruity.

  Hereinafter, embodiments of a display device and a display method according to the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a cross-sectional view of a principal part showing an outline of a configuration of an organic EL display device according to the present invention. Here, an active matrix top emission organic EL display device will be described as an example. As shown in FIG. 1, the organic EL display device 10 is configured by sandwiching a light emitting element 13 between a support substrate 11 and a counter substrate 12.

  The support substrate 11 is appropriately selected from a transparent substrate such as glass or a silicon substrate. Here, since the driving method of the organic EL display device 10 is an active matrix method, a TFT substrate in which TFTs are provided according to the respective light emitting elements 13 is used as the support substrate 11. The support substrate 11 is provided with a drive circuit not shown here. Here, an active matrix type organic EL display device 10 will be described as an example, but the present invention is applicable even if the organic EL display device 10 is a passive matrix type.

  The light emitting element 13 is composed of an organic EL element, and is arranged in a matrix in the display area at the center of the main surface of the support substrate 11. Each of these light emitting elements 13 emits light of, for example, each color of R (red), G (green), and B (blue), and is arranged in a display area according to a predetermined arrangement format. An element isolation insulating layer 14 that separates the light emitting elements 13 is disposed between the light emitting elements 13.

  Each light emitting element 13 is arranged on the support substrate 11 in accordance with each light emitting element 13, and an organic layer 16 including a light emitting layer disposed on the lower electrode 15 and emitting light of each color. In addition, an upper electrode (cathode) 17 serving as a common electrode for each light emitting element 13 is sequentially laminated so as to cover each organic layer 16 and the element isolation insulating layer 14. Although the lower electrode 15 is an anode and the upper electrode 17 is a cathode here, the lower electrode 15 may be a cathode and the upper electrode 17 may be an anode. Further, a transparent material film 18 made of, for example, silicon nitride is provided between the upper electrode 17 and the counter substrate 12.

  Here, as a characteristic configuration of the present invention, a plurality of light receiving elements 19 are arranged at positions between the light emitting elements 13 on the surface side of the counter substrate 12.

  The light receiving element 19 is made of, for example, a PIN (PN) photodiode formed of an amorphous silicon semiconductor, and is provided in a state of embedding a recess 12 a provided on the surface side of the counter substrate 12. The recess 12a is provided by etching or the like before the support substrate 11 and the counter substrate 12 are arranged to face each other.

  Here, it is assumed that the light receiving element 19 is embedded in the recess 12a provided on the surface side of the counter substrate 12. However, the light receiving element 19 may be embedded in the recess provided on the light emitting element 13 side in the counter substrate 12. Good. The light receiving element 19 may be embedded in a recess provided on the counter substrate 12 side of the transparent material film 18.

  The light receiving element 19 receives the leaked light from the light emitting element 13 and outputs an electrical signal according to the amount of received light. Accordingly, as described later, the relative luminance deterioration amount of each light emitting element 13 can be detected based on the input signal to the light emitting element 13 and the output signal from the light receiving element 19. Here, by providing the light receiving element 19 with a limit for detecting only a light amount of 20% or less of the light emission intensity, it is possible to prevent detection of other light scattering leakage amounts and receive only the leaked light from the light emitting element 13. be able to. In addition, the light receiving element 19 has a function of storing the gradation value of the received light.

  In addition, as shown in the plan view of FIG. 2, the light receiving element 19 is disposed between the light emitting elements 13 adjacent in plan view in the scanning direction. For example, one light receiving element 19 is connected to the light receiving element 19. The light leakage amount is monitored at the same period as the scanning period of one light emitting element 13 adjacent in plan view. As a result, only the light leakage amount from one light emitting element 13 adjacent to the light receiving element 19 is received, and the light leakage amount from the other light emitting element 13 is prevented from being received. Here, the A-A ′ sectional view of FIG. 2 is the sectional configuration diagram of FIG. 1.

  The organic EL display device 10 includes a control unit 20 shown in the block diagram of FIG. Based on the input signal to the light emitting element 13 (see FIG. 1) and the output signal from the light receiving element 19, the control unit 20 emits light so that the relative luminance difference with time of each light emitting element 13 becomes constant. The driving of the element 13 is controlled.

  The control unit 20 processes input signals to the respective light emitting elements 13 and outputs them as input data, and processes output signals in accordance with the amount of leakage light detected by the light receiving elements 19, and outputs data. As an output signal processing circuit 22.

  Specifically, the input signal processing circuit 21 includes a first memory unit 21a that stores a digital input signal to the light emitting element 13 in the display unit 30, and a light emitting element 13 stored in the first memory unit 21a. An input signal arithmetic circuit 21b that performs 20% multiplication processing on each input signal to obtain input data is provided. Here, the reason why the input signal calculation circuit 21b is provided is that, as described above, the light receiving element 19 is provided with a limit for detecting only the light leakage amount of 20% or less of the light emission intensity. This is because the signal level output from the processing circuit 21 corresponds to the signal level output from the light receiving element 19 via the output signal processing circuit 22.

  In this example, the input signal is multiplied by 20%. However, the output signal processing circuit 22 (to be described later) also outputs the output signal from the input signal processing circuit 21 by multiplying the output signal by 5 times. The signal level to be output can correspond to the signal level output from the light receiving element 19 via the output signal processing circuit 22.

  On the other hand, the output signal processing circuit 22 divides the output signal corresponding to the amount of leakage light detected by the light receiving element 19 by the gradation value stored in the light receiving element 19, and the division value. An analog-digital converter (ADC) 22b for converting into a digital signal and a second memory unit 22c for storing the digitally converted output signal as output data are provided.

  In the output signal arithmetic circuit 22a, by dividing the output signal by the gradation value, the voltage value detected by the light receiving element 19 one line before the scanning direction is subtracted from the voltage value detected by the light receiving element 19. Thus, the light emitting element 13 and the light receiving element 19 for monitoring the amount of light leakage can be associated with each other.

  The control unit 20 includes a data detection unit 23 to which input data of each light emitting element 13 from the input signal processing circuit 21 and output data of each light emitting element 13 from the output signal processing circuit 22 are input, and data A luminance deterioration amount calculation circuit 24 that calculates the relative luminance deterioration amount of each light emitting element 13 for one frame based on the input data from the input signal processing circuit 21 passed through the detection unit 23 and the output data from the output signal processing circuit 22. It has.

  In addition, the control unit 20 includes a voltage value calculation circuit 25 that calculates a voltage value corresponding to the deterioration of each light emitting element 13 from the relative luminance deterioration amount of each light emitting element 13 calculated by the luminance deterioration amount calculation circuit 24, and a voltage value Difference in voltage value of deterioration between the light emitting element 13 indicating the voltage value of the smallest deterioration in one frame and the light emitting elements 13 other than the light emitting element 13 from the voltage value of deterioration calculated by the arithmetic circuit 25. The voltage value difference calculation circuit 26 is calculated. Further, the control unit 20 includes a selection control circuit 27 that applies and corrects the difference between the voltage values to the input signal of each light emitting element 13 excluding the light emitting element 13 indicating the voltage value corresponding to the smallest deterioration. . As a result, the luminance decrease due to the deterioration of each light emitting element 13 is corrected in accordance with the light emitting element 13 having the smallest relative luminance deterioration amount in one frame.

  Here, it is assumed that the voltage value calculation circuit 25, the voltage value difference circuit 26, and the selection control circuit 27 incorporate a correspondence table between the calculated voltage value and the luminance. As a result, when performing luminance correction, it is possible to inquire each circuit as to how much luminance value the calculated voltage value corresponds to, so that smooth correction is possible.

  Next, the display method of the display device described above will be described with reference to the block diagram of FIG. 3 and the flowchart of FIG. Note that the display method of the present invention can be applied to a moving image or a still image.

Here, as an example, correction of one light emitting element 13 (bright display element 13a) that is brightly displayed with a large decrease in luminance and light emitting element 13 (dark display element 13b) that is darkly displayed with the smallest relative luminance deterioration amount. explain. Here, for example, the light-emitting element 13 that is brightly displayed indicates the light-emitting element 13 that emits light with a luminance higher than 1 cd / m ² , and the light-emitting element 13 that is darkly displayed is a light-emitting element that emits light with a luminance of 1 cd / m ² or less. 13 shall be pointed out.

  First, digital input signals to the respective light emitting elements 13 are stored in the first memory unit 21a (S101). It is assumed that the input signal is controlled so that the luminance gradually decreases in both the light-emitting element 13 that is brightly displayed and the light-emitting element 13 that is darkly displayed to prevent burn-in. Next, the input signal is read from the first memory unit 21a, the input signal calculation processing unit 21b performs multiplication processing of 20% of the input signal, and this value is used as input data (S102).

  On the other hand, in the light receiving element 19, monitoring is performed sequentially and continuously at the same period as the scanning period of each light emitting element 13. In the light receiving element 19, the gradation value of the leaked light detected from each light emitting element 13 is stored, and the leaked light quantity is photoelectrically converted (S201).

  Next, in the output signal circuit 22a, the photoelectrically converted output signal is divided by the gradation value (S202). Next, the ADC 22b performs A / D conversion on the division value (S203) and stores it as output data in the second memory unit 22c (S204).

Then, the input data and the output data are input to the data detection unit 23 (S301). Next, the luminance deterioration amount calculation circuit 24 calculates the relative luminance deterioration amount of each light emitting element 13 for one frame (S302). Here, as an example, as shown in FIG. 5, the relative luminance deterioration amount (ΔL _a ) of the bright display element 13a is 7%, and the relative luminance deterioration amount (ΔL _b ) of the dark display element 13b is 2%. It is assumed that there is (ΔL _a > ΔL _b ).

Next, the voltage value calculation circuit 25 calculates a voltage value for the deterioration from the relative luminance deterioration amount of each light emitting element 13 (S303). Here, the 7% relative luminance deterioration amount (ΔL _a ) of the bright display element 13a corresponds to 1.4V, and the 2% relative luminance deterioration amount (ΔL _b ) of the dark display element 13b corresponds to 0.4V. I will do it.

  Thereafter, in the voltage value difference calculation circuit 26, the degradation voltage between the light emitting element 13 having the smallest voltage value corresponding to the relative luminance degradation amount for one frame and each light emitting element 13 other than the light emitting element 13. A value difference is calculated (S304). Here, the difference in the voltage value corresponding to the deterioration between the dark display element 13b and the bright display element 13a is 1.0V.

  Subsequently, the selection control circuit 27 performs correction by applying the voltage value difference calculated by the voltage value difference calculation circuit 26 to each of the light emitting elements 13 other than the light emitting element 13 having the smallest degradation voltage value. (S305). Here, correction is performed by applying 1.0 V to the input signal of the bright display element 13a. Here, the series of corrections as described above are performed in a period in which the deterioration of contrast is not visually recognized between the bright image display unit and the dark image display unit, and the calculation process and the correction process are performed within the non-display period. To be done.

  According to such a display device and display method, in accordance with the light emitting element 13 (dark display element 13b) having the smallest relative luminance deterioration amount, the relative luminance difference with time of each light emitting element 13 is constant. In order to control the driving of each light emitting element 13 excluding this light emitting element 13, correction is made so that the luminance decrease due to the deterioration of each light emitting element 13 becomes constant. As a result, brightness control for preventing burn-in can be performed with good controllability, so that contrast is maintained between the bright image display unit and the dark image display unit. Therefore, even when a still image is displayed for a long time, image sticking can be reduced without causing a sense of incongruity.

(Modification 1)
In addition, the display method described in the first embodiment can be applied to a moving image or a still image, but the difference in the relative luminance deterioration amount of each light emitting element 13 displays a still image for a long time. This is especially true for still images. For this reason, before performing the correction of each light emitting element 13 as described above, it is possible to recognize whether the image is a moving image or a still image and perform the correction only when the image is a still image.

  In this case, as shown in FIG. 6, for example, a moving image / still image recognition circuit 41 is provided between the first memory unit 21a and the input signal calculation circuit 21b of the input signal processing circuit 21 (see FIG. 3). Suppose that

The moving image / still image recognition circuit 41 uses the output voltage value (V _1N ) of the N frame and the output voltage value (V _{1 (N-1)} ) of the N−1 frame, and calculates the following equation (1). A video frame output voltage calculation circuit 41a that performs processing, and a moving image / still image determination circuit 41b that determines whether the image is a moving image or a still image based on a value calculated by the video frame output voltage calculation circuit 41a are provided.

  In the case where such a moving image / still image recognition circuit 41 is provided in the control unit 20, when the moving image / still image determination circuit 41b determines that it is 70% or more based on the result of the arithmetic processing of the above equation (1). When the moving image is less than 70%, it is determined as a still image. At this time, if it is determined as a still image, detection of the transition of the subtle measurement level before and after is detected by a value obtained by multiplying the numerical value of each measurement signal level before and after video frame recognition by 100 times. It is preferable to facilitate the calculation. For example, the input signal is input to the input signal calculation circuit 21b only when it is determined as a still image.

(Second Embodiment)
Next, a second embodiment of the display device according to the present invention will be described with reference to FIG. In the first embodiment, the top emission organic EL display device has been described as an example. In the present embodiment, an example of a bottom emission organic EL display device 10 ′ will be described. In addition, the same number is attached | subjected and demonstrated to the structure similar to the display apparatus demonstrated in 1st Embodiment.

  As shown in FIG. 7, in the case of the bottom emission type, since the emitted light from the organic layer 16 is extracted from the support substrate 11 side, the upper electrode 17 is made of a reflective material, and the lower electrode 15 is made of a transparent material. It is formed. Here, the lower electrode 15 is disposed in a state corresponding to each light emitting element 13 on a planarization insulating film (not shown) provided in a state of covering the TFT disposed on the support substrate 11. The light receiving element 19 ′ is disposed on the planarization insulating film between the lower electrodes 15 so as to be separated from the adjacent lower electrodes 15. Further, in order to detect leakage light of the light emitting element 13 by the light receiving element 19 ′, the element isolation insulating layer 14 disposed so as to cover the light receiving element 19 ′ is made of a transparent material.

  Even when the organic EL display device 10 ′ having such a configuration is used, the display method similar to that of the first embodiment can be performed, and the relative luminance difference with time between the bright display element 13a and the dark display element 13b is constant. Since the drive of the light emitting element 13 can be controlled so as to be, the same effects as those of the first embodiment can be obtained. Note that Modification 1 of the first embodiment is also applicable to the second embodiment.

  In the first and second embodiments, examples of the organic EL display devices 10 and 10 ′ including the light emitting elements 13 that emit RGB colors have been described. However, the present invention is not limited to this, and white The present invention is applicable even to an organic EL display device including a light emitting element that emits light. Moreover, in the said 1st Embodiment and the said 2nd Embodiment, although demonstrated using the example of the organic electroluminescence display, this invention is not limited to an organic electroluminescence display, It is provided with self-light emitting elements, such as PDP. It can be applied to other display devices.

1 is a configuration cross-sectional view for explaining a first embodiment according to a display device of the present invention. It is a top view for demonstrating 1st Embodiment which concerns on the display apparatus of this invention. It is a block diagram for demonstrating 1st Embodiment which concerns on the display apparatus of this invention. It is a flowchart for demonstrating 1st Embodiment which concerns on the display method of this invention. It is a graph which shows the relative luminance degradation amount of the bright display element and dark display element of 1st Embodiment which concerns on the display method of this invention. It is a block diagram for demonstrating the modification 1 of 1st Embodiment which concerns on the display method of this invention. It is a structure sectional view for explaining a 2nd embodiment concerning a display of the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10, 10 '... Organic EL display device, 11 ... Support substrate, 12 ... Opposite substrate, 13 ... Light emitting element, 13a ... Bright display element, 13b ... Dark display element, 19, 19' ... Light receiving element, 20 ... Control part, 24 ... Luminance deterioration amount calculation circuit, 25 ... Voltage value calculation circuit, 26 ... Voltage value difference calculation circuit, 27 ... Selection control circuit

Claims (8)

A plurality of light-emitting elements formed in an array between a pair of substrates;
A light receiving element that is disposed between the light emitting elements of one of the pair of substrates and that detects photoelectric leakage of the light emitting element and performs photoelectric conversion;
A control unit that controls driving of each light emitting element based on an input signal to the light emitting element and an output signal from the light receiving element so that a relative luminance difference with time of each light emitting element becomes constant; A display device characterized by that. The display device according to claim 1,
The display device, wherein the light receiving element is configured to monitor the amount of light leakage at the same period as a scanning period of one of the light emitting elements adjacent to the light receiving element. The display device according to claim 1,
The controller is
A luminance deterioration amount calculation circuit for calculating a relative luminance deterioration amount of each of the light emitting elements based on the input signal and the output signal;
A voltage value difference calculation circuit for calculating a difference between the voltage values corresponding to a difference in the relative luminance deterioration amount between the light emitting element having the smallest relative luminance deterioration amount and each of the light emitting elements other than the light emitting element;
A display device comprising: a selection control circuit that applies and corrects a difference between the voltage values to the input signals of the light emitting elements excluding the light emitting element with the smallest relative luminance deterioration amount. The display device according to claim 3, wherein
The control unit includes a signal processing circuit that processes at least one of the input signal and the output signal so that the signal level of the input signal and the signal level of the output signal correspond to each other.
The display device, wherein the luminance deterioration amount calculation circuit calculates a relative luminance deterioration amount of each light emitting element based on the input signal and the output signal processed by the signal processing circuit. The display device according to claim 3, wherein
The control unit includes a voltage value calculation circuit that calculates a voltage value corresponding to the relative luminance deterioration amount from the relative luminance deterioration amount of each light emitting element calculated by the luminance deterioration amount calculation circuit. And
The voltage value difference calculation circuit calculates a difference between the voltage values of the light emitting element having the smallest degradation voltage value calculated by the voltage value calculation circuit and each of the light emitting elements other than the light emitting element. A display device. The display device according to claim 3, wherein
The control unit includes a moving image / still image recognition circuit that recognizes a moving image or a still image based on the input signal and determines whether it is a moving image or a still image, and only the input signal recognized as a still image is included. A display device configured to be input to the luminance deterioration amount calculation circuit. Leakage light of each light emitting element is detected by a light receiving element, and a relative luminance difference with time of each light emitting element is constant based on an input signal to the light emitting element and an output signal photoelectrically converted by the light receiving element. The display method characterized by controlling drive of each said light emitting element. The display method according to claim 7,
Calculating a relative luminance deterioration amount of each light emitting element based on the input signal and the output signal;
Calculating a voltage value difference corresponding to a difference in the relative luminance deterioration amount between the light emitting element having the smallest relative luminance deterioration amount and each light emitting element other than the light emitting element;
Applying a difference between the voltage values to the input signals of the light emitting elements other than the light emitting element with the smallest relative luminance deterioration amount to correct the display signal.

Images