JP2008292867A - Contrast control device, self-luminous display device, electronic equipment and contrast control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To optimize the operation for suppressing image persistence according to the display content. <P>SOLUTION: One-frame average value of pixel data constituting an input frame image is calculated. Thereafter, N-frame average value (N is a natural number of ≥2) of the one-frame average values is calculated for each N-frame period. A differential value between the previous N-frame average value and the latest N-frame average value is calculated, and presence/absence of motion of the input frame image is determined by comparing the differential value with a determination threshold B. The category type of the input frame image is determined based on a plurality of motion determination results based on combinations of the N-frame average value and the determination threshold B. The contrast is sequentially variably controlled based on a contrast reduction ratio α and a unit reduction ratio D corresponding to the determination result of category type. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The invention described in this specification relates to a technique for suppressing a burn-in phenomenon of a self-luminous display panel.
The invention has aspects as a cathode potential control device, a self-luminous display device, an electronic device, and a cathode potential control method.

  Various types of display display panels currently exist in self-luminous display panel displays. In particular, the organic EL display not only has excellent viewing angle and responsiveness, but also can achieve high brightness and high contrast. Therefore, it is expected as a next generation display device.

By the way, the organic EL element and other self-light-emitting elements have a characteristic of deteriorating in proportion to the light emission amount and the light emission time. In addition, the deterioration speed has different characteristics depending on the types of light emitting elements and the light emitting materials.
On the other hand, the content of the display image is not uniform. For this reason, the deterioration of the self-luminous element is likely to proceed partially.

For example, the self-luminous element in the time display area (fixed display area) progresses more rapidly than the self-luminous element in other display areas (moving image display area).
The luminance of the self-luminous element that has deteriorated is relatively lowered as compared with the luminance of other display areas. In general, a state in which a luminance difference between self-luminous elements is perceived by a human is called “burn-in”.

When “burn-in” occurs between different emission colors, a white balance shift phenomenon (coloring phenomenon) also occurs.
However, the occurrence of the “burn-in” phenomenon cannot be zero in principle. For this reason, various suppression methods have been studied conventionally. Some of them are listed below.

JP 2003-150110 A JP 2002-169509 A JP 2002-207475 A JP-A-8-248934 JP 2000-356981 A Japanese Patent Laid-Open No. 5-61426 JP 2003-228329 A JP 2003-295827 A JP 2000-132139 A JP 2001-175221 A

  However, the conventional image sticking suppression technique only determines binary whether the display content is a still image or a moving image, and there is a problem that the execution target of the control operation is limited to the determination of a still image. For this reason, in the case of a display device that is supposed to input various images, there is a problem that the execution period of the suppression operation is very short relative to the display time, and a sufficient suppression effect cannot be obtained.

  Of course, it is also possible to increase the execution period of the suppression operation by loosening the still image criterion. However, there is a limit to the suppression effect in relation to image quality degradation.

  Therefore, the inventors propose a contrast control device having the following processing functions.

(A) 1 frame average value calculation unit for calculating 1 frame average value of pixel data constituting the input frame image (b) N (N is a natural number of 2 or more) frame average value for each N frame period (C) calculates a difference value between the immediately preceding N frame average value and the latest N frame average value, and compares the difference value with the determination threshold B to determine the input frame image Motion determination unit for determining presence / absence of motion (d) Pixel genre determination unit (e) for determining the genre type of the input frame image based on a plurality of motion determination results based on a combination of N frame average value and determination threshold B Contrast reduction control unit for successively and variably controlling the contrast based on the contrast reduction rate α and the unit reduction rate D corresponding to the determination result of the genre type

  Here, the variable control of the contrast is executed by sequentially variably controlling one or both of the black level reference voltage and the white level reference voltage of the data line driver, for example. The contrast variable control is realized by sequentially variably controlling one or both of a black level gradation value and a white level gradation value that define an upper limit value and a lower limit value of a gamma conversion characteristic, for example.

  In the case of the invention proposed by the inventors, the reduction amount of contrast can be adjusted in multiple steps according to the display contents. For example, the reduction amount of contrast can be adjusted between an image with a large amount of motion and an image with a small amount of motion even in a moving image. As a result, some burn-in suppression control corresponding to the display content can be executed in most display periods. Thereby, the progress of image sticking can be effectively suppressed as compared with the conventional method.

Hereinafter, the case where the invention is applied to contrast control of an active matrix driving type organic EL panel module 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 illustrated or described in particular 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-1) Overall Configuration FIG. 1 shows the main components of the organic EL panel module 1. The organic EL panel module 1 includes an organic EL panel 3, a data line driver 5, a scanning line driver 7, and a contrast control unit 9 as main components.

  In the effective display area of the organic EL panel 3, pixels 11 are arranged in a matrix according to the panel resolution. In the case of this embodiment, the organic EL panel 3 is for color display, and the pixels 11 are arranged according to the arrangement of emission colors. However, when an organic EL element having a structure in which organic light emitting layers of a plurality of colors are stacked constitutes the pixel 11, one pixel corresponds to a plurality of light emission colors.

  FIG. 2 shows a connection relationship between the internal structure of the pixel 11 corresponding to the active matrix driving method and other driving circuits. However, the actual pixel 11 is provided with a transistor for controlling the light emission period, a transistor corresponding to a threshold correction function and a mobility correction function of the drive transistor, and the like.

The pixel 11 includes a write control transistor T1, a charge holding capacitor C, a current driving transistor T2, and an organic EL element D.
The write control transistor T1 is a thin film transistor that controls writing of the signal voltage Vdata corresponding to the pixel data to the charge retention capacitor C.

  The opening / closing operation of the write control transistor T1 is controlled by a write signal WS supplied from the scan line driver 7 through the scan line WL. Pixel data (signal voltage Vdata) applied through the data line DL is written into the charge storage capacitor C during the period in which the write control transistor T1 is closed.

  The current driving transistor T2 is a thin film transistor that supplies a driving current having a magnitude corresponding to the signal voltage Vdata written in the charge holding capacitor C to the organic EL element D. In the case of FIG. 2, an N-channel field effect transistor is used as the current driving transistor T2.

The data line driver 5 is a circuit device that applies a signal voltage Vdata corresponding to pixel data to the data line DL. The data line driver 5 has a configuration in which one digital / analog conversion circuit is arranged for one data line DL.
The scanning line driver 7 is a circuit device that gives the write timing of the signal voltage Vdata. The scanning lines WL to which the write timing is supplied are sequentially switched and controlled in units of horizontal scanning periods.

  The contrast control unit 9 is a processing device that estimates the genre of a display image from pixel data using a plurality of determination criteria, and variably controls the contrast of the display image according to the estimation result. In the case of this embodiment, the contrast control unit 9 controls the contrast by variably controlling the black level reference voltage Vref_b and the white level reference voltage Vref_w of each digital / analog converter constituting the data line driver 5.

FIG. 3 shows an internal configuration example of the contrast control unit 9. The contrast control unit 9 includes a one-frame average value calculation unit 21, a motion determination unit 23, an image genre determination unit 25, and a contrast reduction control unit 27.
Here, the one-frame average value calculation unit 21 is a processing device that calculates a one-frame average value APL (average picture level) of all pixel data constituting the input frame pixel.

The motion determination unit 23 sets the N (N is a natural number) frame average value Cj (j is a subscript for representing the context of two N frame average values) of the one frame average value APL calculated for each frame. A processing device for determining a motion of a current input image based on the current input image.
In the case of this embodiment, four motion determination units 23 having different combinations of the average number of calculated frames and the determination threshold B are arranged, and independent determination processes are executed. That is, the movement is determined based on four determination criteria.

FIG. 4 illustrates an internal configuration example of the motion determination unit 23. The motion determination unit 23 includes an N frame average value calculation unit 31 corresponding to the set number of calculated frames, a storage area 33 that stores the calculation results, and a motion determination unit 35 that uses the set determination threshold B. It is configured.
FIG. 5 shows how the N frame average value Cj is calculated in the N frame average value calculation unit 31.

The storage area 33 is composed of a semiconductor memory or other storage medium. The storage area 33 holds the N frame average value Cj calculated immediately before the difference value of the N frame average value Cj is calculated.
The motion determination unit 35 is a processing device that compares the difference value between the N frame average value calculated immediately before and the newly calculated N frame average value with the determination threshold B to determine the presence or absence of motion.

For example, when the difference value is larger than the determination threshold B, the motion determination unit 35 determines that the input image is a moving image. On the other hand, when the difference value is smaller than the determination threshold B, the motion determination unit 35 determines that the input image is a still image.
As a result, the image genre determination unit 25 is given four determination results with different determination criteria.

  The image genre determination unit 25 is a processing device that determines a genre of a display image based on four determination results and determines a unit reduction rate D for contrast control according to the determination genre. FIG. 6 shows the correspondence between the combination of determination results and the unit reduction rate D. Note that the motion determination unit 35 having a small difference value determination threshold B has a characteristic that it is easier to detect the movement of the display image than the motion determination unit 35 having a large difference value determination threshold B.

In addition, even when the determination threshold B is the same, the motion determination unit 35 having a smaller number of calculated frames of the N frame average value Cj has a characteristic that it is easier to detect the movement of the display image than the motion determination unit 35 having a larger number of calculated frames. .
Using this characteristic, the image genre determination unit 25 determines the presence / absence and the degree of movement of the input image as the genre type.

  For example, when all four motion determination units 23 determine that the image is a still image, the image genre determination unit 25 determines that the input image is a still image, and the largest unit reduction among the five genres prepared in advance. Set the rate D1.

  Also, for example, only the motion determination unit 23 with the determination threshold value B1 (<B2) and the average number of calculated frames is N1 (<N2) determines a still image, and the other three motion determination units 23 are moving images. Is determined, the image genre determination unit 25 sets the second largest unit reduction ratio D2 among the five genres prepared in advance.

  Also, for example, when the two motion determination units 23 with the determination threshold B1 (<B2) determine that they are still images, and when the two motion determination units 23 with the determination threshold B2 determine that they are moving images, the image genre determination unit 25 sets the third largest unit reduction ratio D3 among the five genres prepared in advance.

  Also, for example, only the motion determination unit 23 with the determination threshold value B2 (> B1) and the average calculated number of frames N2 (> N1) determines that it is a still image, and the other three motion determination units 23 are moving images. The image genre determination unit 25 sets the fourth largest unit reduction ratio D4 among the five genres prepared in advance.

  Further, for example, when all four motion determination units 23 determine a moving image, the image genre determination unit 25 sets the fifth largest unit reduction rate D5 among the five genres prepared in advance. The unit reduction rate D5 is zero. This is because image sticking hardly occurs in a moving image with a lot of movement.

The contrast reduction control unit 27 sets the contrast reduction rate α (including zero) according to the set unit reduction rate D, and the black level reference voltage Vref_b and the white level so as to satisfy the set reduction rate α. A processing device that generates a reference voltage Vref_w.
FIG. 7 shows an example of the internal configuration of the contrast reduction control unit 27.

As shown in FIG. 7, the contrast reduction control unit 27 includes a reduction rate calculation unit 41 as a digital signal processing unit and a reference voltage generation unit 43 as a variable voltage source.
When the determination of the same genre information continues, the reduction rate calculation unit 41 updates the reduction rate α to a value that is larger by the corresponding unit reduction rate D.

  Since the unit reduction rate D is appropriately determined according to the amount of motion of the display image, even if the contrast reduction rate α changes, the change is not perceived. Here, the reduction rate α is given by assuming that the contrast at the initial setting is 100%.

However, when the reduction rate α, which is the cumulative value of the unit reduction rate D, exceeds the upper limit value E, there is a possibility that a reduction in image quality is perceived more than the burn-in suppression effect. Therefore, the reduction rate calculation unit 41 performs control so that the calculated reduction rate α does not exceed the upper limit value E.
Note that the reduction rate calculation unit 41 gives the reference voltage generation unit 43 half of the reduction rate α.

  The reference voltage generation unit 43 generates a voltage obtained by lowering the white level reference voltage Vref_w by a half of the reduction rate α, and simultaneously generates a voltage by raising the black level reference voltage Vref_b by a half of the reduction rate α. To do. Here, the reference voltage generator 43 is required to be able to generate a number of voltage values. For example, it comprises a digital potentiometer.

(A-2) Contrast Control Operation Example Hereinafter, the contents of the processing operation executed by the contrast control unit 9 will be described.
FIG. 8 shows processing operations executed by the motion determination unit 23 constituting the contrast control unit 9. Of course, the 1-frame average value calculation unit 21 calculates the screen average value for each frame.

The four motion determination units 23 each calculate an N frame average value Cj based on the calculated number of frames (S1).
When a new N frame average value Cj + 1 is calculated, the motion determination unit 23 calculates a difference value from the N frame average value Cj calculated immediately before, and at the same time, whether the difference value is equal to or greater than the determination threshold B. It is determined whether or not (S2). Of course, the determination threshold value B here is a determination threshold value associated with the motion determination unit 23.

Here, if a positive result is obtained, the motion determination unit 23 determines that the currently input display image is a moving image (S3). On the other hand, if a negative result is obtained, the motion determination unit 23 determines that the display image currently being input is a still image (S4).
Here, each of the four motion determination units 23 outputs a determination result at a timing corresponding to the number of calculated frames.

Therefore, the output timing of the determination result is different between the motion determination unit 23 with the calculated number of frames N1 and the motion determination unit 23 with the number of calculated frames N2.
FIG. 9 shows processing operations executed by the moving image genre determination unit 25 and the contrast reduction control unit 27 constituting the contrast control unit 9.

  First, the moving image genre determination unit 25 determines the genre of the input image based on the four determination results existing at each determination time (S11). Specifically, a corresponding unit reduction rate D is set. When the unit reduction rate D is zero, the moving image genre determination unit 25 sets the reduction flag to off. On the other hand, when the unit reduction rate D is non-zero, the moving image genre determination unit 25 sets the reduction flag to ON.

  Next, the contrast reduction control unit 27 determines whether the reduction flag is on (S12). When a positive result is obtained, the contrast reduction control unit 27 proceeds to the determination process of processing step S13. When a negative result is obtained, the contrast reduction control unit 27 proceeds to the process of processing step S14.

  In processing step S13, it is determined whether or not the previous frame is the same genre information. Specifically, it is determined whether or not the unit reduction rate D is the same. In process step S14, a process of setting the reduction rate α to zero is executed. This is because the image is intensely moving, and contrast reduction control for suppressing burn-in is unnecessary.

  When a positive result is obtained in the determination process of process step S13, the contrast reduction control unit 27 proceeds to the process of process step S15. When a negative result is obtained, the contrast reduction control unit 27 proceeds to the process of process step S16. .

In process step S15, update processing of the reduction ratio α is executed. Specifically, a process of adding the unit reduction rate D to the current reduction rate α is executed.
In process step S16, the process which sets the reduction rate (alpha) to zero is performed. This is because the unit reduction ratio D is different even when contrast reduction control is performed. However, as long as the reduction flag is on, a method of updating the reduction rate α using the unit reduction rate D having a value different from that of the previous frame may be employed.

When the setting or updating process of the reduction rate α is completed, the contrast reduction control unit 27 determines whether or not the reduction rate α is equal to or lower than the upper limit value E (S17).
Here, when a negative result is obtained (that is, when the reduction rate α exceeds the upper limit value E), the contrast reduction control unit 27 resets the reduction rate α to the upper limit value E (S18).

After this, or when an affirmative result is obtained in processing step S17, the contrast reduction control unit 27 outputs the given reduction rate α to the reference voltage generation unit 27.
The reference voltage generation unit 27 uses half of the reduction ratio α for the variable amount of the white level reference voltage Vref_w, and uses the other half for the variable amount of the black level reference voltage Vref_b.

  FIG. 10 shows a contrast reduction control image. The vertical axis in FIG. 10 represents the luminance level at the initial setting as 100%. The horizontal axis in FIG. 10 represents the maximum gradation value of the pixel data as 100%. It can be seen that the change width of the luminance level is reduced by the contrast reduction control.

(A-3) Effect of Embodiment As described above, in the case of this embodiment, the unit reduction rate D of the contrast is changed according to the image content (genre information), and the same image is input. As long as it continues, a method of increasing the reduction ratio α up to the upper limit E is adopted. Thereby, the burn-in suppression effect can be adjusted according to the content of the image.

Further, the unit reduction ratio D and the upper limit value E are determined according to the content of the image (genre information), and it is possible to minimize deterioration in image quality due to contrast variable control.
Furthermore, the contrast control unit 9 described in this embodiment does not require a large storage area.

  Therefore, it can be realized with a small system. Therefore, it can be mounted on an existing timing generator or the like. As a result, it is not necessary to design or change a new panel arrangement, which is excellent in terms of manufacturing cost.

(B) Embodiment 2
FIG. 11 shows main components of the organic EL panel module 51. In FIG. 11, parts corresponding to those in FIG.
The organic EL panel module 51 includes the organic EL panel 3, the data line driver 5, the scanning line driver 7, the gamma conversion unit 53, and the contrast control unit 55 as main components.

There are two components that are unique to this embodiment: a gamma converter 53 and a contrast controller 55.
The gamma conversion unit 53 is a processing device that performs gradation conversion of pixel data using a variably set gamma conversion table. That is, in this embodiment, contrast reduction control is realized by gamma conversion processing of pixel data.

The contrast controller 55 is a processing device that sets a contrast reduction rate α (including zero) according to the set unit reduction rate D and sets a gamma conversion table so as to satisfy the set reduction rate α. is there.
FIG. 12 shows an internal configuration example of the contrast control unit 55. FIG. 12 shows parts corresponding to those in FIG.

As shown in FIG. 12, the contrast control unit 55 includes a one-frame average value calculation unit 21, a motion determination unit 23, an image genre determination unit 25, and a contrast reduction control unit 61. Therefore, the difference from the first embodiment is only the contrast reduction control unit 61.
FIG. 13 shows an internal configuration example of the contrast reduction control unit 61. FIG. 13 shows parts corresponding to those in FIG.

The contrast reduction control unit 61 shown in FIG. 13 includes a reduction rate calculation unit 41 and a gamma conversion table setting unit 63 as a digital signal processing unit.
That is, only the function of setting the gamma conversion table using the reduction rate α calculated by the reduction rate calculation unit 41 is different.

FIG. 14 shows a setting example of the gamma conversion table. Also in this embodiment, the white level (maximum gradation level) is reduced by half of the reduction ratio α, and the black level (minimum gradation level) is increased by half of the reduction ratio α. Set the output relationship. This gamma conversion provides an effect of lowering the peak luminance level of the display image and simultaneously raising the black level.
As a result, it is possible to achieve the same effect as in the first embodiment.

(C) Other Embodiments (C-1) Other Contrast Control Methods In the above-described embodiments, the method of variably controlling both the black level and the white level in the screen has been described. That is, the case where the white level is pushed down at the same time that the black level in the screen is raised has been described.

  However, only one of them may be controlled. For example, as shown in FIG. 15, the black level may be controlled to be increased by the reduction rate α. In this case, since the peak luminance level does not decrease, it is possible to prevent a decrease in visibility.

Further, for example, as shown in FIG. 16, the white level may be controlled to be reduced by the reduction rate α. In this case, since the peak luminance level can be lowered, the power consumption can be lowered at the same time.
Moreover, you may perform combining these control methods.

First, the genre that tends to burn-in is controlled so that the peak luminance level is lowered to a certain value, and when this certain value is reached, the black level is then raised to a certain value. The curve may be controlled so as to make it difficult to contrast (bend in a convex shape so as to satisfy γ << 2).
Note that any of the above-described control methods can be applied when gamma conversion is performed on pixel data.

(C-2) Genre Type Characteristic Method In the embodiment described above, the case where the genre type is determined using four types of motion determination units having different numbers of calculated frames and different determination thresholds has been described.
However, the number of motion determination units used for genre determination may be two or more.

(C-3) Product example (a) Drive IC
In the above description, the organic EL panel module in which the pixel array unit (organic EL panel) and the drive circuit (data line driver, scanning line driver, cathode potential control unit, etc.) are formed on one substrate has been described.

  However, the pixel array section and the drive circuit section can be manufactured separately and distributed as independent products. For example, the drive circuits may be manufactured as independent drive ICs (integrated circuits) and distributed independently from the pixel array unit.

(B) Display module The organic EL panel modules 1 and 51 according to each of the above-described embodiments can be distributed in the form of a panel module 71 having an appearance configuration shown in FIG.
The panel module 71 has a structure in which a facing portion 73 is bonded to the surface of the support substrate 75.

The facing portion 73 is made of glass or other transparent member as a base material, and a color filter, a protective film, a light shielding film, and the like are arranged on the surface thereof.
The panel module 71 may be provided with an FPC (flexible printed circuit) 77 for inputting / outputting signals and the like to / from the support substrate 75 from the outside.

(C) Electronic device The organic EL panel modules 1 and 51 in the embodiment described above are also distributed in a product form mounted on an electronic device.
FIG. 18 illustrates a conceptual configuration example of the electronic device 81. The electronic device 81 includes the organic EL panel module 83 and the system control unit 85 described above. The processing content executed by the system control unit 85 differs depending on the product form of the electronic device 81.

Note that the electronic device 81 is not limited to a device in a specific field as long as it has a function of displaying an image or video generated in the device or input from the outside.
As this type of electronic apparatus 81, for example, a television receiver is assumed. FIG. 19 shows an appearance example of the television receiver 91.

  A display screen 97 including a front panel 93, a filter glass 95, and the like is disposed on the front surface of the television receiver 91. The portion of the display screen 97 corresponds to the organic EL panel module 1 (51) described in the embodiment.

  Further, for example, a digital camera is assumed as this type of electronic apparatus 81. FIG. 20 shows an example of the appearance of the digital camera 101. FIG. 20A shows an example of the appearance on the front side (subject side), and FIG. 20B shows an example of the appearance on the back side (photographer side).

  The digital camera 101 includes a protective cover 103, an imaging lens unit 105, a display screen 107, a control switch 109, and a shutter button 111. Among these, the part of the display screen 107 corresponds to the organic EL panel module 1 (51) described in the embodiment.

For example, a video camera is assumed as this type of electronic device 81. FIG. 21 shows an appearance example of the video camera 121.
The video camera 121 includes an imaging lens 125 that images a subject in front of the main body 123, a shooting start / stop switch 127, and a display screen 129. Among these, the display screen 129 corresponds to the organic EL panel module 1 (51) described in the embodiment.

  In addition, for example, a portable terminal device is assumed as this type of electronic device 81. FIG. 22 shows an example of the appearance of a mobile phone 131 as a mobile terminal device. A cellular phone 131 illustrated in FIG. 22 is a foldable type, and FIG. 22A illustrates an appearance example in a state where the housing is opened, and FIG. 22B illustrates an appearance example in a state where the housing is folded.

  The mobile phone 131 includes an upper housing 133, a lower housing 135, a connecting portion (in this example, a hinge portion) 137, a display screen 139, an auxiliary display screen 141, a picture light 143, and an imaging lens 145. Among these, the display screen 139 and the auxiliary display screen 141 correspond to the organic EL panel module 1 (51) described in the embodiment.

Further, for example, a computer is assumed as this type of electronic device 81. FIG. 23 shows an example of the appearance of the notebook computer 151.
The notebook computer 151 includes a lower casing 153, an upper casing 155, a keyboard 157, and a display screen 159. Among these, the display screen 159 corresponds to the organic EL panel module 1 (51) described in the embodiment.

  In addition to these, the electronic device 81 may be an audio playback device, a game machine, an electronic book, an electronic dictionary, or the like.

(C-3) Other Pixel Circuit Examples In the above-described embodiments, the case where the current driving transistor T2 is an N-channel field effect transistor has been described.
However, the present invention can also be applied to the case where the current driving transistor T2 is configured by a P-channel field effect transistor.

FIG. 24 shows an example of a pixel circuit when the current driving transistor T2 is a P-channel field effect transistor. In FIG. 24, the same reference numerals are given to the portions corresponding to FIG.
In the case of this pixel circuit, the charge holding capacitor C is connected to hold the voltage Vdata corresponding to the pixel data between the power supply potential VSS and the gate electrode of the current driving transistor T2.

(C-4) Other display device examples In the description of the embodiments, the case of applying to an organic EL panel module has been described.
However, the contrast control function according to the invention can also be applied to other self-luminous display devices.

For example, the present invention can be applied to an inorganic EL display device, a display device in which LEDs are arranged, and other display devices in which light emitting elements having a diode structure are arranged on a screen.
In the case of the embodiment described above, the active matrix driving method is adopted, but the present invention can also be applied to the passive matrix driving method.

(C-5) Other Implementation Method of Control Device In the above description, the case where the contrast control function is implemented mainly by software processing has been described.
However, a part of the contrast control function may be realized by an application specific IC or other hardware device.

(C-6) Others 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 which shows the circuit structure of an organic electroluminescent panel module. It is a figure which shows the connection relation of a pixel circuit and a peripheral circuit. It is a figure which shows the internal structural example of a contrast control part. It is a figure which shows the internal structural example of a motion determination part. It is a figure which shows the calculation principle of N frame average value. It is a figure which shows the correspondence of the combination of a determination result, and a unit reduction rate. It is a figure which shows the internal structural example of a contrast reduction control part. It is a flowchart which shows a motion determination operation | movement. It is a flowchart which shows a genre determination operation | movement and reduction ratio setting operation | movement. It is a figure which shows the control operation of contrast. It is a figure which shows the circuit structure of an organic electroluminescent panel module. It is a figure which shows the internal structural example of a contrast control part. It is a figure which shows the internal structural example of a contrast reduction control part. It is a figure which shows the control operation of contrast. It is a figure which shows the other example of control operation of contrast. It is a figure which shows the other example of control operation of contrast. It is a figure which shows the structural example of a display module. It is a figure which shows the function structural example of an electronic device. It is a figure which shows the example of goods of an electronic device. It is a figure which shows the example of goods of an electronic device. It is a figure which shows the example of goods of an electronic device. It is a figure which shows the example of goods of an electronic device. It is a figure which shows the example of goods of an electronic device. It is a figure which shows the other pixel circuit example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Organic EL panel module 3 Organic EL panel 9 Contrast control part 21 1 frame average value calculation part 23 Motion determination part 25 Image genre determination part 27 Contrast reduction control part 31 N frame average value calculation part 33 Storage area 35 Motion determination part 41 Reduction Rate calculation unit 43 Reference voltage generation unit 51 Organic EL panel module 53 Gamma conversion unit 55 Contrast control unit 61 Contrast reduction control unit 63 Gamma conversion table setting unit

Claims (7)

A contrast control device for a self-luminous display panel,
A one-frame average value calculating unit for calculating a one-frame average value of pixel data constituting the input frame image;
An N frame average value calculating unit that calculates N (N is a natural number of 2 or more) frame average values of the one frame average value for each N frame period;
A motion determination unit that calculates a difference value between the previous N frame average value and the latest N frame average value, and determines the presence or absence of motion of the input frame image by comparing the difference value with the determination threshold B;
A pixel genre determination unit that determines a genre type of an input frame image based on a plurality of motion determination results based on a combination of the N frame average value and the determination threshold B;
A contrast control apparatus comprising: a contrast reduction control unit that sequentially and variably controls the contrast based on a contrast reduction rate α and a unit reduction rate D corresponding to a determination result of a genre type. The contrast control device according to claim 1,
The contrast reduction control unit variably controls the contrast by variably controlling one or both of a black level reference voltage and a white level reference voltage of the data line driver. The contrast control device according to claim 1,
The contrast reduction control unit increases the contrast reduction rate α by the unit reduction rate D to the upper limit value E when the determination of the same genre type corresponding to the contrast reduction control is continued. The contrast control device according to claim 1,
It has a gamma conversion unit that performs gamma conversion of pixel data based on gamma conversion characteristics set so as to satisfy the black level gradation value and the white level gradation value, and supplies the pixel data after the gamma conversion to the data line driver. ,
The contrast reduction control unit sequentially and variably controls one or both of a black level gradation value and a white level gradation value that define an upper limit value and a lower limit value of the gamma conversion characteristic. A self-luminous display panel;
A one-frame average value calculating unit for calculating a one-frame average value of pixel data constituting the input frame image;
An N frame average value calculation unit for calculating an N frame average value of the one frame average value (N is a natural number of 2 or more) every N frame periods;
A motion determination unit that calculates a difference value between the previous N frame average value and the latest N frame average value, and determines the presence or absence of motion of the input frame image by comparing the difference value with the determination threshold B;
A pixel genre determination unit that determines a genre type of an input frame image based on a plurality of motion determination results based on a combination of the N frame average value and the determination threshold B;
A self-luminous display device comprising: a contrast reduction control unit that sequentially and variably controls contrast based on a contrast reduction rate α and a unit reduction rate D corresponding to a determination result of a genre type. A self-luminous display panel;
A one-frame average value calculating unit for calculating a one-frame average value of pixel data constituting the input frame image;
An N frame average value calculating unit that calculates N (N is a natural number of 2 or more) frame average values of the one frame average value for each N frame period;
A motion determination unit that calculates a difference value between the previous N frame average value and the latest N frame average value, and determines the presence or absence of motion of the input frame image by comparing the difference value with the determination threshold B;
A pixel genre determination unit that determines a genre type of an input frame image based on a plurality of motion determination results based on a combination of the N frame average value and the determination threshold B;
A contrast reduction control unit that sequentially and variably controls the contrast based on the contrast reduction rate α and the unit reduction rate D corresponding to the determination result of the genre type;
A system controller;
An electronic device comprising: an operation input unit for the system control unit. In the contrast control method of the self-luminous display panel,
Processing for calculating an average value of one frame of pixel data constituting an input frame image;
A process of calculating an N frame average value (N is a natural number greater than or equal to 2) frame average values for each N frame period;
A process of calculating a difference value between the previous N frame average value and the latest N frame average value and comparing the difference value with a determination threshold B to determine the presence or absence of motion of the input frame image;
A process of determining a genre type of an input frame image based on a plurality of motion determination results based on a combination of the N frame average value and the determination threshold B;
And a process of successively and variably controlling the contrast based on the contrast reduction rate α and the unit reduction rate D corresponding to the determination result of the genre type.

Images