JP2007240803A - Spontaneous light emission display device, black level correcting device and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a spontaneous light emission display device etc., capable of reproducing all the gray scale information on a screen, including even the low-gray-scale range, regardless of the deterioration state in an effective display area. <P>SOLUTION: Dummy pixels by basic primary colors and a luminance detection sensor which detects their light emission luminance by the basic primary colors are arranged outside an effective display area. Then the spontaneous light emission display device includes a black level detection section which detects the operating voltage of a data line driver part corresponding to the lowest point, where gray scale variations can be actually observed by the basic primary colors, based on the measured luminance characteristics of the dummy pixels by the basic primary colors; and a reference voltage setting section which generates a set of reference voltages, the minimum voltage of which is the detected operating voltage and supplies it to the data line driver part for the corresponding basic primary color. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The invention described in this specification relates to a technique for correcting a black level in consideration of a secular change in luminance characteristics of a self-luminous display device.
The invention proposed by the inventors has aspects such as a self-luminous display device, a black level correction device, and a program.

Flat panel displays are widely used in products such as computer displays, portable terminals, and televisions. Currently, many liquid crystal display panels are mainly used. However, 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-described viewing angle and responsiveness problems, and can achieve a thin form, high brightness, and high contrast that do not require a backlight. Therefore, it is expected as a next-generation display device that replaces the liquid crystal display.

  By the way, the organic EL element and other self-light-emitting elements have a characteristic of deteriorating according to the light emission amount and the light emission time. For this reason, when the deviation of the light emission amount and the light emission time continues partially on the display screen, the variation in the deterioration degree of the self-light emitting element is observed as a luminance difference. This state is called “burn-in”.

Since burn-in causes a reduction in image quality, improvement techniques have been studied.
JP 2003-228329 A JP 2000-132139 A JP 2003-509728 A JP 2004-361628 A JP 2005-017520 A

  By the way, it is known that luminance degradation generally does not proceed at the same ratio over all gradations. FIG. 1 exemplarily shows how the luminance characteristic of a certain self-luminous element changes according to the degree of progress of deterioration. As shown in FIG. 1, the decrease in luminance is particularly large on the low gradation side. As a result, the gradation expression on the low gradation side cannot be performed. Such a phenomenon in which the low gradation range is not expressed is referred to as a “blackout” phenomenon.

If the luminance degradation proceeds at the same ratio in all gradation displays, the low gradation area can be expressed without any problem. However, as shown in FIG. 1, the actual deterioration characteristic is that the luminance deterioration in the low gradation region is accelerated.
Therefore, a method of setting the black level high in advance in anticipation of a decrease in luminance can be considered. However, if the black level is increased in advance, the “black float” phenomenon is observed in the initial state. This state causes a decrease in contrast.
Thus, there is a need for a mechanism that can ensure gradation expression in a low gradation region in accordance with the deterioration state of the self-luminous element.

As a method for estimating the deterioration state of the organic EL element, a method of integrating the gradation values of the input video signal can be considered.
However, the degradation state cannot be grasped only by simple information such as the gradation value of the input video signal, but the influence of the surrounding environment where the self-luminous display device is installed, driving method, luminance condition, heat generation condition, etc. Receive. In addition, the deterioration state affects not only the condition at the time of determination but also the deterioration state so far.

Theoretically, all the effects of these deterioration factors are identified in advance through experiments, and the accuracy of deterioration state prediction is improved by creating a data table that correlates the gradation values of the input video signal and the deterioration characteristics (deterioration amount). Can be increased.
However, this kind of experiment has many conditions, and it is estimated that it is very difficult to accurately associate the gradation value of the input video signal with the deterioration characteristic (deterioration amount).

In addition, it is necessary to correct the estimation operation while detecting the surrounding environmental conditions. Further, in a developing display device, it is almost impossible to accurately associate a gradation value with a deterioration characteristic (deterioration amount).
Even if the gradation value and the deterioration characteristic are associated with a certain degree of accuracy, it is necessary to consider the characteristic variation between the display panels. As described above, it is virtually impossible to improve the prediction accuracy of deterioration characteristics (deterioration amount) through experiments.

  In view of this, the inventors propose a mechanism that can ensure gradation expression in a low gradation region regardless of the deterioration state of the self-light-emitting element. A dummy pixel for each basic primary color and a luminance detection sensor for detecting the emission luminance for each basic primary color are arranged outside the effective display area.

(A) Mechanism 1
As one mechanism, the inventors propose the adoption of the processing function unit shown below.
(A) Except for the measurement timing of the luminance characteristic, the dummy pixels for each basic primary color are continuously controlled to emit light with the gradation value of the reference pixel that changes the gradation value reflecting the content of the input video signal. At the measurement timing, dummy pixel data determination processing for controlling light emission in a time-sharing manner for dummy pixels corresponding to each basic primary color with a plurality of gradation values capable of grasping gamma characteristics (b) Based on the emission luminance detected for each basic primary color, Luminance characteristic detection processing for detecting the luminance characteristic of the dummy pixel corresponding to each basic primary color (c) Based on the luminance characteristic for each basic primary color, the operating voltage of the data line driving unit corresponding to the lowest point at which gradation change can be observed Black level detection process for detecting the basic primary color (d) A reference voltage setting process for generating a set of reference voltages having the detected operating voltage as the minimum voltage and supplying the reference voltage to the data line driving unit for the corresponding basic primary color

(B) Mechanism 2
As one mechanism, the inventors propose the adoption of the processing function unit shown below.
(A) Except for the measurement timing of the luminance characteristic, the dummy pixels for each basic primary color are continuously controlled to emit light with the gradation value of the reference pixel that changes the gradation value reflecting the content of the input video signal. At the measurement timing, dummy pixel data determination processing for controlling light emission in a time-sharing manner for dummy pixels corresponding to each basic primary color with a plurality of gradation values capable of grasping gamma characteristics (b) Based on the emission luminance detected for each basic primary color, Luminance characteristic detection processing for detecting the luminance characteristic of the dummy pixel corresponding to each basic primary color (c) Based on the detected luminance characteristic for each basic primary color, the input video signal corresponding to the lowest point at which gradation change can be observed Black level detection process for detecting gradation values (d) Conversion table calculation process for calculating the input / output relationship of the data conversion table using the gradation value detected by the black level detection unit as the minimum output value for each basic primary color (e) Based on the issued conversion table, the video signal conversion processing for converting the input tone values to output tone values

  According to the invention proposed by the inventors, the same black level can always be set based on the deterioration state in the effective display area measured through the dummy pixels. That is, regardless of the deterioration state in the effective display area, all gradation information including the low gradation area can be reproduced on the screen.

Hereinafter, an example of an organic EL display device equipped with the black level correction function according to the invention will be described.
In addition, the well-known or well-known technique of the said technical field is applied to the part which is not specifically illustrated or described in this specification.
Moreover, the form example demonstrated below is one form example of invention, Comprising: It is not limited to these.

(A) Form example 1
(A) Functional Configuration of Organic EL Display Device FIG. 2 shows a functional configuration example of the organic EL display device 1.
The organic EL display device 1 includes an organic EL panel 3, a luminance detection sensor 5, a color-specific luminance characteristic detection unit 7, a black level detection unit 9, a reference voltage setting unit 11, a data line driving circuit 13, an average gradation value for each color ( (APL) calculation unit 15, dummy pixel data determination unit 17, and dummy pixel data multiplexing unit 19.

The organic EL panel 3 includes an effective display area 31 and dummy pixels 33.
The effective display area 31 is a display area in which one pixel on the display composed of three basic primary colors is arranged in a matrix.
The dummy pixel 33 is an area that does not contribute to display of an image formed for detecting the gamma characteristic of the organic EL element. In this example, only one dummy pixel 33 is arranged outside the effective display area 31.

The dummy pixel 33 is covered with a casing made of an impermeable material or the like so that the emitted light cannot be observed from the outside.
FIG. 3 shows a pixel arrangement example of the effective display area 31 and the dummy pixels 33. In the case of FIG. 3, the effective display area 31 is arranged from the first line to the Nth line, and the dummy pixel 33 is arranged in the (N + 1) th line. Accordingly, the pixel data of the dummy pixel 33 is updated using the blanking period.

In the case of FIG. 3, the basic primary colors constituting one pixel on the display are three colors of red (R), green (G), and blue (B). In this specification, a unit light emission region corresponding to the basic light emission color is also referred to as a dummy pixel.
The organic EL panel 3 can be realized only by adding one selection line (gate drive line) to a general display panel. In other words, the existing driving circuits (data line driving circuit and selection line driving circuit) can be used for driving the dummy pixels 33. Therefore, a dedicated drive circuit for the dummy pixels 33 and a large-scale drive circuit are not necessary.

The luminance detection sensor 5 is a sensor device that detects the light emission luminance of the dummy pixel 33 at every luminance characteristic measurement timing. The luminance detection sensor 5 is disposed at a position facing the dummy pixel 33 so as to cover the entire light emitting region.
FIG. 4 shows an arrangement example of the luminance detection sensor 5. Only one luminance detection sensor 5 is arranged for three unit light emitting regions (dummy pixels 33).

Therefore, a method of detecting the light emission luminance corresponding to each basic primary color by time division is adopted. For one basic primary color, the luminance detection sensor 5 detects a plurality of light emission luminances. The reason for detecting a plurality of light emission luminances is to ensure white balance over the entire range of gradation values.
FIG. 5 shows a luminance detection image for a certain basic primary color.

The luminance detection sensor 5 detects visible light output from the dummy pixel 33 and converts it into an electrical signal.
An arbitrary detection sensor is applied to the light detection element. For example, a visible light sensor composed of an amorphous silicon semiconductor is used. The light amount information detected as the current value is amplified and converted into a voltage value, and is output to the color-specific luminance characteristic detection unit 7 as a dummy pixel light detection signal.

  The luminance characteristic detection unit 7 for each color is a processing device that detects the luminance characteristic for each basic primary color based on the emission luminance detected for each basic primary color through the luminance detection sensor 5. The luminance characteristic is detected as a deterioration amount (rate) with respect to the initial luminance. The luminance characteristic detection unit 7 for each color detects the current gamma characteristic of the corresponding organic EL element based on a plurality of detected luminance values detected for each basic primary color at each measurement timing.

  Further, the color-specific luminance characteristic detection unit 7 also performs a function of giving the dummy pixel data determination unit 17 a measurement timing and a gradation value to be displayed on the dummy pixel 33 at the time of measurement. The measurement timing is given at regular intervals, for example. Also, a plurality of measurement gradation values are prepared for each basic primary color. Prepare enough gradation values to understand the gamma characteristics.

The black level detection unit 9 is based on the luminance characteristics of each basic primary color, and the data line driving circuit 13 corresponding to the lowest point (0% luminance value) of the range in which the gradation change can be observed (the range in which the luminance change can be observed). It is a processing device that detects the operating voltage of each basic primary color.
The reference voltage setting unit 11 is a processing device that generates a set of reference voltages having the operating voltage as a minimum voltage and supplies the reference voltage to the corresponding data line driving circuit 13 for the basic primary color.
FIG. 6 shows an example of nine reference voltages generated for each basic primary color. The reference voltage corresponds to the equally divided point in the gradation range.

At this time, the reference voltage setting unit 11 sets all the reference voltages including the intermediate gradation range so that the gamma characteristic when changing the gradation value from 0 to 100% is the same as the initial characteristic. The gamma characteristic information is calculated according to the specifications of the data line driving circuit 13 to be used.
FIG. 7 shows an example of calculating the reference voltage. A curve indicated by a dotted line is an initial gamma characteristic (input / output characteristic).

A curve indicated by a broken line is a gamma characteristic before black level correction. In this state, there is no luminance change in the low gradation region, and gradation expression can no longer be performed. This state is “blackout”. Further, the gamma characteristic has a curved shape different from the initial characteristic.
Therefore, as shown by the solid line, the gamma characteristic is set to be the same as the initial characteristic through the setting of the reference voltage value. Note that FIG. 7 shows that the output luminance y has a characteristic of the power of α with respect to the input gradation value x.

The data line driving circuit 13 is a circuit device that applies an analog voltage corresponding to an input display signal (digital value) to a data line corresponding to each pixel. Specifically, the data line driving circuit 13 includes a D / A conversion circuit for the data line.
FIG. 8 shows a configuration example of the data line driving circuit 13. As shown in FIG. 8, each D / A conversion circuit 131 is connected with reference voltage lines 133 corresponding to the number of basic primary colors, and supplied with nine reference voltages Vref.

By individually adjusting the reference voltages applied to these reference voltage lines 133, it is possible to adjust the white balance while maintaining the resolution.
FIG. 9 shows a basic configuration example of a ladder resistance type D / A conversion circuit 131. FIG. 9 shows a basic circuit called 2R-R type. This indicates that the resistance value at the branch destination is 2R (2 × R), and the overall resistance value is R. In the case of this configuration, the current flowing at each branching in turn from the branch point on the reference power supply (maximum output voltage) side is halved. The branched current flows into the input terminals of the switches S1 to S9. The reference power supply corresponds to the above-described reference voltages Vref-R, Vref-G, and Vref-B.

  The switches S1 to S9 are ON / OFF controlled by the main switch 1311 in accordance with an input video signal (n bits) corresponding to each pixel (basic primary color). Each of the switches S1 to S9 applies an inflowing current to the operational amplifier 1313 when it is on, and allows an inflowing current to flow through the ground wire when it is off. As a result, a current corresponding to the gradation value (current sum from each switch) flows into the output resistance r of the operational amplifier. At this time, the voltage appearing at both ends of the output resistor r becomes the output voltage.

  The color-specific APL calculation unit 15 is a processing device that calculates an average luminance value for each basic primary color of all pixels constituting one frame. The calculated average luminance value is used as dummy pixel data in a period other than the timing for measuring the luminance characteristics. The average luminance value is a gradation value that most reflects the content of the input video signal. By continuously controlling the light emission of the dummy pixel 33 with this average luminance value, the deterioration characteristics of the dummy pixel 33 are effectively displayed. It can be matched with the deterioration tendency.

  The dummy pixel data determination unit 17 is a processing device that determines a gradation value to be output as dummy pixel data. The dummy pixel data 17 selects an average gradation value for each basic primary color given from the APL calculation unit 15 for each color other than the measurement timing of the luminance characteristics, and from the luminance characteristic detection unit 7 for each color at the measurement timing of the luminance characteristics. Select a given gradation value for measurement.

  The dummy pixel data multiplexing unit 19 is a processing device that multiplexes dummy pixel data to an input display signal. Specifically, the dummy pixel data multiplexing unit 19 executes a process of multiplexing dummy pixel data at a position corresponding to the (N + 1) th line outside the effective display area 31.

(B) Black Level Correction Operation Hereinafter, the black level correction operation executed in the organic EL display device 1 will be described.
First, along with the start of use, the color-specific APL calculation unit 15 calculates an average gradation value for each frame of the input video signal for each basic primary color, and uses this as dummy pixel data to continuously control the light emission of the dummy pixels 33. Thereby, the luminance deterioration of the dummy pixel 33 proceeds under the same conditions as the average pixel in the effective display area 31.

  Eventually, at the measurement timing, the dummy pixel data determination unit 17 stops outputting the average gradation value for each basic primary color, and sequentially outputs a plurality of designated gradation values that can grasp the gamma characteristics of the light emitting elements in time division. To do. Simultaneously with the output of the gradation value for measuring the luminance characteristics, the luminance detection sensor 5 detects the light emission luminance of each unit light emission region constituting the dummy pixel 33 in order. That is, the light emission luminance corresponding to a plurality of gradation values is detected for each basic primary color.

  Thereafter, the black level detection unit 9 detects the lowest point of the range in which the gradation change can be observed for each basic primary color, and detects the operating voltage of the data line driving circuit 13 corresponding to the lowest point. The detection of the operating voltage may be realized by monitoring the operating current flowing in the data line driving circuit 13 or may be obtained based on the specification of the data line driving circuit 13.

Thus, by detecting the lowest point that can be used for gradation expression at the present time through the measured luminance of the dummy pixel, no previous experiment is required.
When the operating voltage giving 0% luminance is detected for each basic primary color in this way, the reference voltage setting unit 11 changes the emission luminance with respect to the gradation value with the same gamma characteristic as the initial state using the usable luminance range. Thus, a set of reference voltages is generated and supplied to the D / A conversion circuit 131 of the data line driving circuit 13. In this example, nine reference voltages are set.

Thereafter, the data line driving circuit 13 converts the input video signal (gradation value) into an analog voltage according to the newly set reference voltage and applies it to the data line. That is, the corresponding pixel is controlled to emit light.
Of course, after setting the reference voltage, the dummy pixel data determination unit 17 controls the emission of the dummy pixels again with the average gradation value for each basic primary color of the input video signal.

(C) Effect In this embodiment, dummy pixels 33 having basically the same structure as the pixel structure of the effective display area 31 are arranged outside the effective display area, and the average gradation value for each color calculated from the display image is used. Control light emission. For this reason, the luminance degradation of the dummy pixel 33 can be allowed to proceed under the same conditions as the luminance degradation of the effective display region 31 over a long period of time.

  As described above, the luminance characteristics (gamma characteristics) of the organic EL element corresponding to the basic primary color can be accurately determined by actually measuring the emission luminance of the dummy pixels reflecting the deterioration characteristics of the effective display area 31 for a plurality of gradation values. Can grasp.

In addition, the operating voltage of the data line driving circuit 13 corresponding to the lowest point at which the gradation change can be observed among the actually measured luminance characteristics is detected, and a set of reference voltages for supplying the operating voltage to the data line driving circuit 13 is detected. By setting the minimum voltage, it is possible to realize an organic EL display device that does not generate “black floating” or “black shadow”.
In addition, when setting a set of reference voltages, the gamma characteristics realized by the set of reference voltages are controlled to be the same as the gamma characteristics in the initial state. Regardless of the light emission time, the initial state can be maintained.

Note that the organic EL display device according to this embodiment does not require a structure for detecting the amount of light for all the pixels even when the screen size is increased, and the dummy pixels 33 to be arranged are on an extension line of a normal panel process. Can be created (with very little change to the panel process).
That is, the production difficulty of the display panel itself is not increased and the cost is hardly increased. Thus, it is also effective in terms of manufacturing technology.

(B) Embodiment 2
(A) Functional Configuration of Organic EL Display Device Next, another example of the organic EL display device will be described. In the case of the first embodiment, the method for realizing the black level adjustment by adjusting the reference voltage value Vref given to the D / A conversion circuit 131 has been described. However, in this embodiment, a case where the same function is realized through gradation conversion of a video display signal will be described.

FIG. 10 shows a functional configuration example of the organic EL display device 101. In FIG. 10, the same reference numerals are given to the portions corresponding to FIG. 2.
The organic EL display device 101 includes an organic EL panel 3, a luminance detection sensor 5, a color-specific luminance characteristic detection unit 7, a black level detection unit 103, a data line driving circuit 13, a color-specific average gradation value (APL) calculation unit 15, The dummy pixel data determination unit 17, the dummy pixel data multiplexing unit 19, the conversion table calculation unit 105, and the video signal conversion unit 107 are configured.

As described above, the organic EL display device 101 basically has the same configuration as that of the first embodiment except for the black level detection unit 103, the conversion table calculation unit 105, and the video signal conversion unit 107.
The black level detection unit 103 in this embodiment is input corresponding to the lowest point (0% luminance value) of the range in which the gradation change can be observed (the range in which the luminance change can be observed) based on the luminance characteristics for each basic primary color. It functions as a processing device that detects the gradation value of the video signal.

The conversion table calculation unit 105 is a processing device that calculates the input / output relationship of the data conversion table using the gradation value detected by the black level detection unit 103 as the minimum output value for each basic primary color.
FIG. 11 shows an example of the data conversion table. FIG. 11 shows a data conversion table when the gradation value of the video signal after data conversion is given by 10 bits when the gradation value of the input video signal is given by 8 bits. FIG. 11 is an example of conversion when the range in which gradation change can be observed is 50 to 1023. For this reason, the black level of the input gradation value (gradation value “0”) is associated with the output gradation value “50”.

FIG. 12 shows how the gradation value variable range changes before and after gradation conversion by the data conversion table.
At this time, the conversion table calculation unit 105 changes the input level so that the gamma characteristic of the organic EL element becomes the same as the initial characteristic when the converted gradation value is changed from the black level to the maximum gradation value. Sets the correspondence between tone value and output tone value. The data conversion table set in this way is given to the video signal converter 107.

The video signal conversion unit 107 is a processing device that converts an input gradation value into an output gradation value based on a conversion table. The conversion table is stored in, for example, a rewritable semiconductor memory or a magnetic storage medium.
Note that the video signal conversion unit 107 performs gradation conversion on the dummy pixel data except for the measurement timing of the luminance characteristic. That is, in the case of the measurement timing of the luminance characteristic, the dummy pixel data is output with the input gradation as it is. This is to increase detection accuracy.

(B) Black Level Correction Operation Hereinafter, the black level correction operation executed in the organic EL display device 101 will be described.
Also in this case, with the start of use, the color-specific APL calculation unit 15 calculates an average gradation value for each frame of the input video signal for each basic primary color, and uses this as dummy pixel data to continuously control the emission of the dummy pixels 33. Thereby, the luminance deterioration of the dummy pixel 33 proceeds under the same conditions as the average pixel in the effective display area 31.

  Eventually, at the measurement timing, the dummy pixel data determination unit 17 stops outputting the average gradation value for each basic primary color, and sequentially outputs a plurality of designated gradation values that can grasp the gamma characteristics of the light emitting elements in time division. To do. Simultaneously with the output of the gradation value for measuring the luminance characteristics, the luminance detection sensor 5 detects the light emission luminance of each basic light emission region constituting the dummy pixel 33 in order. That is, the light emission luminance corresponding to a plurality of gradation values is detected for each basic primary color.

  Thereafter, the black level detection unit 103 detects the lowest point in the range where the gradation change can be observed for each basic primary color, and detects the gradation value corresponding to the lowest point. In this way, by detecting the lowest point that can be used for gradation expression at the present time through the measured luminance of the dummy pixel, no previous experiment is required. Note that the gradation value corresponding to the lowest point in the range where the gradation change can be observed is detected through reading of dummy pixel data (gradation value) and interpolation calculation, for example.

When the boundary value of the gradation value that gives 0% luminance for each basic primary color is detected in this way, the conversion table calculation unit 105 uses the usable luminance range and performs the same gamma characteristic as the initial state with respect to the gradation value. The data conversion table is calculated for each basic primary color so that the emission luminance changes, and this is reflected in the data conversion table of the video signal conversion unit 107. The reflection of the input / output relationship is executed within the measurement timing.
When the measurement timing is over, the organic EL panel 3 is controlled to emit light with the input video signal subjected to gradation conversion through the video signal converter 107.

(C) Effect As described above, also in this embodiment, an organic EL display device free from the occurrence of “black floating” and “black shadow” can be realized as in the first embodiment.
In addition, when setting the data conversion table, by setting the input / output relationship so that the gamma characteristic based on the converted gradation value is the same as the gamma characteristic in the initial state, the gradation expression power of the organic EL display device can be increased. Regardless of the light emission time, the initial state can be maintained.
Further, in this embodiment, it is not necessary to handle a large number of power supply voltages. For this reason, the circuit configuration of the power supply circuit can be simplified.

(C) Other Embodiments (a) In the embodiment described above, the case where the gradation value given to the dummy pixel other than the measurement timing is set to the average gradation value for each color of the input video signal has been described.
However, the dummy pixel data is not limited to the value described in the embodiment as long as it reflects the content of the input video signal and represents the light emission state in the effective display area.

For example, in the burn-in correction operation in the effective display area that is performed in parallel, when other types of pixels are used as reference pixels that align the deterioration characteristics of each pixel, the gradation value of the pixel may be used.
For example, a gradation value corresponding to a pixel that is most deteriorated may be used as dummy pixel data.

(B) In the above-described embodiment, the case where only one dummy pixel is arranged has been described.
However, a structure in which a plurality of dummy pixels are arranged outside the effective display area 31 may be employed. When a plurality of dummy pixels are used, the influence of the inherent error can be reduced by executing the above-described processing using the average value of the emission luminance detected by each dummy pixel.

(C) In the above-described embodiment, the case where one luminance detection sensor is arranged for three unit light emitting regions has been described.
However, one luminance detection sensor may be arranged for each unit light emitting region.

(D) In the above-described embodiment, the case where the dummy pixel structure is the same as each pixel in the effective display area has been described.
However, the structure of the dummy pixels is not necessarily the same. For example, the dummy pixel may have a structure in which a luminance detection sensor for detecting the light emission luminance of the organic EL element is built in the pixel circuit. Further, the pixel size of the dummy pixel and the size of the basic light emitting area may be changed.

(E) In the above-described embodiment, the case where the basic primary colors are three colors of RGB has been described. However, the basic primary colors can be applied to a case where there are four or more colors including complementary colors. In this case, it is only necessary to prepare as many dummy pixels as the number of these basic primary colors.
(F) In the above-described embodiments, the basic primary colors were not described. However, organic EL elements having different light-emitting element materials may be prepared for each basic primary color, or using a color filter method or a color conversion method. A basic primary color may be generated.

(G) Although the organic EL display panel is illustrated as an example of the self-luminous display device in the above-described embodiment, the present invention can be applied to other self-luminous display devices. For example, the present invention can be applied to FED (field emission display), inorganic EL display panel, LED panel, and the like.

(H) In the above-described embodiment, the black level correction function has been described from the functional aspect. Needless to say, an equivalent function can be realized as hardware or software.
Further, not only all of these processing functions are realized by hardware or software, but some of them may be realized by using hardware or software. That is, a combination of hardware and software may be used.

(I) Various modifications can be considered for the above-described embodiments within the scope of the gist of the invention. Various modifications and applications created or combined based on the description of the present specification are also conceivable.

It is a figure explaining the progress degree of deterioration over time. It is a figure which shows the schematic structural example of an organic electroluminescent display apparatus. It is a figure which shows the pixel arrangement example of an organic electroluminescent panel. It is a figure which shows the arrangement | positioning relationship between a dummy pixel and a brightness | luminance detection sensor. It is a figure which shows a brightness | luminance detection image. It is a figure explaining the calculation example of a reference voltage. It is a figure explaining a mode that the gamma characteristic after black level correction | amendment is maintained to the same characteristic as an initial characteristic by the setting of a reference voltage. It is a figure which shows the internal structural example of a data line drive circuit. It is a figure which shows the circuit structural example of a D / A conversion circuit. It is a figure which shows the schematic structural example of an organic electroluminescent display apparatus. It is a figure which shows an example of a data conversion table. It is a figure explaining the variable range and gamma characteristic of the gradation value after data conversion.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,101 Organic EL display apparatus 5 Luminance detection sensor 7 Color-specific luminance characteristic detection part 9, 103 Black level detection part 11 Reference voltage setting part 13 Data line drive circuit 15 Color-specific APL calculation part 17 Dummy pixel data determination part 105 Conversion table Calculation unit 107 Video signal conversion unit

Claims (8)

A display panel in which dummy pixels for each primary primary color are arranged outside the effective display area;
Other than the measurement timing of the luminance characteristics, the dummy pixels for each basic primary color are continuously controlled to emit light with the gradation value of the reference pixel that changes the gradation value reflecting the content of the input video signal, and the measurement timing of the luminance characteristics Then, a dummy pixel data determination unit for controlling light emission in a time-sharing manner for dummy pixels corresponding to each basic primary color with a plurality of gradation values capable of grasping gamma characteristics,
A luminance detection sensor that detects the emission luminance of the dummy pixel for each basic primary color at each measurement timing;
A luminance characteristic detection unit that detects the luminance characteristic of the dummy pixel corresponding to each basic primary color based on the emission luminance detected for each basic primary color;
Based on the luminance characteristics of each basic primary color, a black level detection unit that detects the operating voltage of the data line driving unit corresponding to the lowest point at which gradation change can be observed, for each basic primary color,
A reference voltage setting unit that generates a set of reference voltages having a minimum operating voltage detected by the black level detection unit and supplies the reference voltage to a corresponding data line driving unit for basic colors Self-luminous display device. A display panel in which dummy pixels for each primary primary color are arranged outside the effective display area;
Other than the measurement timing of the luminance characteristics, the dummy pixels for each basic primary color are continuously controlled to emit light with the gradation value of the reference pixel that changes the gradation value reflecting the content of the input video signal, and the measurement timing of the luminance characteristics Then, a dummy pixel data determination unit for controlling light emission in a time-sharing manner for dummy pixels corresponding to each basic primary color with a plurality of gradation values capable of grasping gamma characteristics,
A luminance detection sensor that detects the emission luminance of the dummy pixel for each basic primary color at each measurement timing;
A luminance characteristic detection unit that detects the luminance characteristic of the dummy pixel corresponding to each basic primary color based on the emission luminance detected for each basic primary color;
A black level detection unit that detects the gradation value of the input video signal corresponding to the lowest point at which gradation change can be observed based on the detected luminance characteristics for each primary primary color;
A conversion table calculation unit that calculates an input / output relationship of a data conversion table having a gradation value detected by the black level detection unit as a minimum output value for each basic primary color;
A self-luminous display device comprising: a video signal conversion unit that converts an input gradation value into an output gradation value based on the calculated conversion table. The self-luminous display device according to claim 1,
The reference voltage setting unit is a set of reference voltage values so that the gamma characteristic of the emission luminance when the input video signal is changed from the minimum gradation value to the maximum gradation value is the same as the gamma characteristic in the initial state. A self-luminous display device characterized by: The self-luminous display device according to claim 2,
The conversion table calculation unit inputs the data conversion table so that the gamma characteristic of the emission luminance when the input video signal is changed from the minimum gradation value to the maximum gradation value is the same as the gamma characteristic in the initial state. A self-luminous display device characterized by calculating an output relationship. A device for correcting a black level in a self-luminous display device in which dummy pixels for each primary primary color and a luminance detection sensor for detecting the emission luminance are arranged outside the effective display area,
Other than the measurement timing of the luminance characteristics, the dummy pixels for each basic primary color are continuously controlled to emit light with the gradation value of the reference pixel that changes the gradation value reflecting the content of the input video signal, and the measurement timing of the luminance characteristics Then, a dummy pixel data determination unit for controlling light emission in a time-sharing manner for dummy pixels corresponding to each basic primary color with a plurality of gradation values capable of grasping gamma characteristics,
A luminance characteristic detection unit that detects the luminance characteristic of the dummy pixel corresponding to each basic primary color based on the emission luminance detected for each basic primary color;
Based on the luminance characteristics of each basic primary color, a black level detection unit that detects the operating voltage of the data line driving unit corresponding to the lowest point at which gradation change can be observed, for each basic primary color,
A reference voltage setting unit that generates a set of reference voltages having a minimum operating voltage detected by the black level detection unit and supplies the reference voltage to a corresponding data line driving unit for basic colors Black level correction device. A device for correcting a black level in a self-luminous display device in which dummy pixels for each primary primary color and a luminance detection sensor for detecting the emission luminance are arranged outside the effective display area,
Other than the measurement timing of the luminance characteristics, the dummy pixels for each basic primary color are continuously controlled to emit light with the gradation value of the reference pixel that changes the gradation value reflecting the content of the input video signal, and the measurement timing of the luminance characteristics Then, a dummy pixel data determination unit for controlling light emission in a time-sharing manner for dummy pixels corresponding to each basic primary color with a plurality of gradation values capable of grasping gamma characteristics,
A luminance characteristic detection unit that detects the luminance characteristic of the dummy pixel corresponding to each basic primary color based on the emission luminance detected for each basic primary color;
A black level detection unit that detects the gradation value of the input video signal corresponding to the lowest point at which gradation change can be observed based on the detected luminance characteristics for each primary primary color;
A conversion table calculation unit that calculates an input / output relationship of a data conversion table having a gradation value detected by the black level detection unit as a minimum output value for each basic primary color;
A black level correction apparatus comprising: a video signal conversion unit that converts an input gradation value into an output gradation value based on the calculated conversion table. A computer program that autonomously adjusts the black level of a self-luminous display device in which dummy pixels for each basic primary color and a luminance detection sensor for detecting the emission luminance are arranged outside the effective display area through computer processing. There,
Other than the measurement timing of the luminance characteristics, the dummy pixels for each basic primary color are continuously controlled to emit light with the gradation value of the reference pixel that changes the gradation value reflecting the content of the input video signal, and the measurement timing of the luminance characteristics Then, a process for controlling the light emission in a time-sharing manner for the dummy pixels corresponding to each basic primary color with a plurality of gradation values that can grasp the gamma characteristic,
Processing for detecting the luminance characteristics of the dummy pixels corresponding to each basic primary color based on the emission luminance detected for each basic primary color;
Based on the luminance characteristics for each basic primary color, a process for detecting the operating voltage of the data line driving unit corresponding to the lowest point at which gradation change can be observed for each basic primary color,
A computer program for generating a set of reference voltages having a detected operating voltage as a minimum voltage and supplying the reference voltage to a corresponding data line driving unit for basic colors. A computer program that autonomously adjusts the black level of a self-luminous display device in which dummy pixels for each basic primary color and a luminance detection sensor for detecting the emission luminance are arranged outside the effective display area through computer processing. There,
Other than the measurement timing of the luminance characteristics, the dummy pixels for each basic primary color are continuously controlled to emit light with the gradation value of the reference pixel that changes the gradation value reflecting the content of the input video signal, and the measurement timing of the luminance characteristics Then, a process for controlling the light emission in a time-sharing manner for the dummy pixels corresponding to each basic primary color with a plurality of gradation values that can grasp the gamma characteristic,
Processing for detecting the luminance characteristics of the dummy pixels corresponding to each basic primary color based on the emission luminance detected for each basic primary color;
A process for detecting a gradation value of an input video signal corresponding to the lowest point at which gradation change can be observed based on the detected luminance characteristics for each primary color;
A process of calculating the input / output relationship of the data conversion table with the gradation value detected by the black level detection unit as the minimum output value for each basic primary color;
The computer program which performs the process which converts an input gradation value into an output gradation value based on the calculated conversion table.

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