JP2009069555A - Apparatus for driving self light-emitting display panel, electronic device and method for driving self light-emitting display panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for driving a self light-emitting display panel, electronic device and method for driving the self light-emitting display panel, wherein, when driving a self light-emitting panel such as an organic EL display panel, the driving can be achieved by a simple configuration, the cost of a power supply circuit can be reduced and complicated control is not required. <P>SOLUTION: The brightness of a content such as an image to be displayed on an organic EL panel 4 which is driven by a prescribed voltage supplied from a power supply circuit 2 provided with a regulator through a driver 3 is determined in accordance with a lighting rate for displaying each content within a voltage range to be driven by the power supply circuit 2, and upon displaying each content, the content is displayed by the determined brightness. Further, it is also available to determine the brightness while considering the lighting rate and lighting pixel distribution. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a driving device for a self-luminous display panel such as an organic electroluminescence display panel, an electronic device including the driving device, and a driving method for a self-luminous display element.

  Development of a display panel in which a large number of self-luminous elements are used as pixels and these are arranged in a matrix has been widely promoted. As one of such display panels, a display panel using an organic electroluminescence (organic EL) element using an organic material as a light emitting layer as a pixel has already been commercialized.

  The organic EL display panel can be replaced with a configuration including a light emitting element having a diode characteristic electrically and a parasitic capacitance component coupled in parallel to the light emitting element. It is known that a light emission drive current flows in a state where a voltage equal to or higher than the light emission threshold voltage unique to the element is applied in the forward direction of the element, and emits light with a luminance substantially proportional to the drive current value.

  That is, since the light emission luminance has a characteristic that depends on the current value, the organic EL display panel often emits light with high luminance so that the visibility is not deteriorated no matter what content is displayed. The power supply circuit that drives the EL display panel needs to be able to output a voltage sufficient to supply a drive current that emits light with high luminance.

  On the other hand, when an on-vehicle device is provided with an organic EL display panel, power is supplied to the on-vehicle device from a battery mounted on the vehicle. However, since the voltage supplied from the battery fluctuates while the vehicle is running, in order to operate stably in the in-vehicle device, it is converted to a stable voltage lower than the battery voltage using a stabilizing circuit such as a regulator. Often supplied inside.

  However, as described above, the organic EL display panel outputs a voltage sufficient to supply a driving current that can emit light with high brightness so that visibility is not deteriorated no matter what content is displayed. In some cases, the supplied voltage is not sufficient, and a booster circuit such as a DC / DC converter must be added to boost the voltage to be output, which increases the cost of the power supply circuit.

  In order to solve such a problem, a method for driving a light emitting display panel described in Patent Document 1 has been proposed as a method for reducing the size of a power supply circuit for driving an organic EL light emitting panel.

The driving method of the light emitting display panel described in Patent Document 1 includes a lighting rate calculation unit that calculates a lighting rate of a pixel in the display panel, and the light emission luminance of each pixel according to the lighting rate obtained by the lighting rate calculation unit. Brightness control means for controlling, and when the lighting rate is high, the drive voltage value output from the brightness control means is controlled to be lowered.
JP 2007-114308 A

  The driving method of the light-emitting display panel described in Patent Document 1 performs luminance control while always calculating, so that the scale of the control circuit increases or the number of steps of a program or the like increases and becomes complicated. Although the scale of the circuit can be reduced, there is a problem that the cost of the control circuit, the microcomputer, etc. increases.

  Therefore, the present invention can be realized with an easy configuration, for example, when driving a self-luminous display panel such as an organic EL display panel, can reduce the cost of a power supply circuit, and does not require complicated control. It is an object to provide a driving device for a self-luminous display panel, an electronic apparatus, and a driving method for the self-luminous display panel.

  In order to solve the above problem, a driving device for a self-luminous display panel according to claim 1 is provided with a self-luminous display panel and a regulator that supplies a predetermined voltage to the self-luminous display panel. In the drive device of the light emitting display panel, content for displaying the brightness of the self light emitting display panel on the self light emitting display panel so that the voltage supplied to the self light emitting display panel is within the maximum voltage supplied by the regulator. Luminance storage means preliminarily stored for each content according to the lighting rate of the pixel at the time of display, and when displaying the content, the luminance preliminarily stored in the luminance storage means for each content And luminance changing means for reading and changing the self-luminous display panel to the luminance.

  The self-luminous display panel driving method according to claim 5, wherein the self-luminous display panel driving method supplies a predetermined voltage to the self-luminous display panel with a regulator. When displaying the content by setting in advance the luminance corresponding to the lighting rate of the pixel when displaying the content to be displayed on the self-luminous display panel so as to be within the maximum voltage supplied by the regulator, and displaying the content The self-luminous display panel is changed to a predetermined luminance according to the content.

  A light emitting display panel driving apparatus according to an embodiment of the present invention will be described below. The driving device of the light emitting display panel according to the embodiment of the present invention turns on the pixel for each content displayed on the self light emitting display panel so that the voltage supplied to the self light emitting display panel is within the maximum voltage supplied by the regulator. Since the luminance of the self-luminous display panel is predetermined and stored in the luminance storage unit according to the rate, the luminance light-emitting unit reads and changes the luminance determined in the luminance storage unit when displaying the content on the self-luminous display panel. Visibility can be maintained even when driven without using a booster circuit. Further, since the brightness is changed to a predetermined brightness for each content, it is not necessary to always calculate the brightness, and the control system can be simplified.

  Further, the luminance may be determined so as to decrease as the lighting rate increases. By doing so, it is possible to set the luminance to be within the voltage that can be supplied by the regulator and the luminance that does not significantly reduce the visibility of the content.

  The luminance may be determined in advance according to the distribution of lighting pixels and the lighting rate when content is displayed on the self-luminous display panel. By doing in this way, the brightness | luminance which considered distribution of the lighting pixel can be set. For example, it is possible to prevent the luminance from becoming higher than necessary when the lit pixels are partially biased.

  In addition, the driving device for the self-luminous display panel according to any one of claims 1 to 3 may be provided in an electronic device. In this way, in an electronic device provided with a self-luminous display panel, a booster circuit is not necessary in the power supply circuit, and brightness can be controlled with a simple configuration and visibility can be maintained.

  A driving method of a light emitting display panel according to an embodiment of the present invention includes a luminance corresponding to a lighting rate of a pixel when a content to be displayed on a self light emitting display panel is displayed so as to be within a voltage range supplied by a regulator. Since the brightness is predetermined for each display and changed to a preset brightness when displaying the content, visibility can be maintained even if the output of the regulator is driven without boosting. In addition, since the luminance is set in advance for each content, it is not necessary to always calculate the luminance, and the control system can be configured simply.

  An embodiment of the present invention will be described with reference to FIGS. An organic EL panel drive device 1 as a drive device for a self-luminous display panel according to an embodiment of the present invention includes a power supply circuit 2, a driver 3, an organic EL panel 4, a controller 5, and a microcomputer 6. For example, the display function of the in-vehicle device is performed as a part of the in-vehicle device mounted on the vehicle.

  The power supply circuit 2 converts the voltage supplied from the in-vehicle battery into a predetermined voltage by a built-in regulator and supplies the converted voltage to the driver 3.

  The driver 3 is supplied with a power supply voltage from the power supply circuit 2 and is also driven by supplying a voltage corresponding to lighting / non-lighting and luminance of each pixel of the organic EL panel 4 input from the controller 5 to the organic EL panel 4. To do.

  The organic EL panel 4 as a self-luminous display panel is a display panel in which a large number of pixels composed of organic EL elements using an organic material for a light emitting layer are arranged in a matrix. Content is displayed by a combination of Lighting / non-lighting of each pixel is controlled by the driver 3 and emits light with a luminance corresponding to the power supply voltage supplied from the driver 3.

  The controller 5 converts the content data and luminance data output from the microcomputer 6 into lighting / non-lighting and luminance data of each pixel of the organic EL panel 4 and outputs the data to the driver 3.

  A microcomputer 6 serving as a brightness changing means and a brightness storing means is a microcomputer having a built-in CPU, memory, and the like. The contents to be displayed on the organic EL panel 4 are stored in advance, and brightness data in each content is also stored in advance. Has been. Then, the content to be displayed is read according to the operation performed by the user through an operation unit (not shown) and the like and output to the controller 5 together with the luminance data. The content data and the luminance data may be stored in an external memory or various storage devices.

  Here, the content is a display content or a display pattern displayed on the organic EL panel 4, and is a still image or a moving image composed of a picture, characters, or a combination thereof. That is, the brightness is set in advance according to the type of these still images and moving images. In the case of a moving image, for example, the luminance may be set based on a value obtained by averaging the lighting rates for each frame of the entire moving image.

  Next, setting of luminance for each content will be described with reference to FIG. FIG. 2 is an example of content displayed on the organic EL panel 4. In FIG. 2, L indicates a lighting region, and D indicates a non-lighting region. For example, FIG. 2A shows a white image on the entire surface and the lighting rate is 100% (only L and no D). FIG. 2B shows the lighting rate of about 70% (L is large and D is large). 2 (c) shows a case where the lighting rate is about 20% (L is small and D is large).

  In general, when the lighting rate is large, even if the luminance of each pixel is lowered, the entire content does not feel dark, so the visibility is not lowered much (the visibility can be maintained). On the contrary, when the lighting rate is small, if the luminance of each pixel is lowered, the entire content becomes dark and the visibility is significantly lowered.

  Therefore, the luminance corresponding to the lighting rate of each content is set within a range where the operation can be performed with the power supply voltage supplied from the power supply circuit 2. That is, when the lighting rate is high, the current flowing through each pixel is decreased by lowering the luminance, and the operation is performed within the voltage range supplied from the power supply circuit 2 (below the maximum voltage that can be supplied by the power supply circuit 2). When the lighting rate is small, since the number of pixels to be lit is small, the current supplied to the organic EL panel 4 is small, so that the operation can be performed within the range of the voltage supplied from the power supply circuit 2 without reducing luminance. In other words, the pixel lighting rate when displaying content to be displayed on the self-luminous display panel is large so that the luminance of the self-luminous display panel is within the maximum voltage supplied by the regulator. It is predetermined for each content so that it becomes lower as it goes.

  For example, in the case of FIG. 2, the brightness is set to 50% in FIG. 2A, the brightness is set to 75% in FIG. 2B, and the brightness is set to 90% in FIG. Can be operated within the range of the power supply voltage to be displayed, and can be displayed without significantly reducing the visibility.

  Next, in the organic EL panel drive device 1 having the above-described configuration, an operation when displaying content will be described with reference to the flowchart shown in FIG. The flowchart shown in FIG. 3 is executed by the CPU of the microcomputer 6.

  First, in step S1, for example, it is determined whether or not there is a content display instruction by a user operation or the like, and if there is a content display instruction (in the case of Y), the process proceeds to step S2, and if there is no instruction ( In the case of N), the process waits in this step.

  Next, in step S2, the instructed content data and the luminance data corresponding to the content data are read from the memory of the microcomputer 6 that has been stored in advance and output to the controller 5, and the process proceeds to step S3. In the controller 5, the content data and luminance data output from the microcomputer 6 are converted into lighting / non-lighting and luminance data of each pixel of the organic EL panel 4 and output to the driver 3, and the driver 3 is input from the controller 5. The organic EL panel 4 is driven with a voltage corresponding to the lighting / non-lighting of each pixel of the organic EL panel 4 and the luminance. Then, each pixel of the organic EL panel 4 emits light with the set luminance, and the content is displayed.

  Next, in step S3, for example, it is determined whether or not there is an instruction to switch to another content by the user's operation or the like, and if there is a content switching instruction (in the case of Y), the process returns to step S2 to instruct If there is no (N), the process waits in this step.

  According to the present embodiment, the brightness of the content displayed on the organic EL panel 4 is set according to the lighting rate when each content is displayed within the voltage range that can be driven by the power supply circuit 2, and each content is displayed. In this case, since the display is displayed with the set brightness, it is not always necessary to display with the high brightness such as the maximum brightness, and therefore the drive voltage can be lowered, so that the booster circuit can be deleted from the power supply circuit 2. Visibility can be maintained.

  Further, since the luminance is switched to the luminance set in advance for each content, it is not necessary to always calculate the luminance, and it is only necessary to store the luminance data set in advance together with the content data in a memory or the like.

  In the above-described embodiment, the luminance is determined only by the lighting rate. However, the luminance may be determined in consideration of the distribution of lighted pixels. For example, when displaying content as shown in FIG. 4, FIG. 4 does not have a lighting area on the right side of FIG. Therefore, the lighting rate is about 35%, which is half of FIG. 2B. Therefore, if the luminance is set only by the lighting rate, the luminance is set higher than that in FIG. 2B. However, since the lighting region in FIG. 4 is the same as the lighting region on the left side of FIG. 2B, the same visibility as in FIG. 2B should be ensured even with the same luminance as in FIG. Therefore, by setting the luminance in consideration of the distribution of the lit pixels, it is possible to drive at a lower voltage while ensuring visibility.

  In the above-described embodiments, the organic EL panel 4 is used as a self-luminous display panel. However, the organic EL panel 4 is not limited to this, and an inorganic EL panel, an FL tube (also referred to as a fluorescent lamp or a fluorescent display tube (VFD)), an LED matrix, or the like. It can be applied to a self-luminous display panel.

  Moreover, you may provide the organic EL panel drive device 1 mentioned above in electronic devices, such as vehicle equipment, household appliances, and a portable device. By providing the organic EL panel driving device 1 described above, a booster circuit is not required in a power supply circuit in an electronic device using a self-luminous display panel such as the organic EL panel 4, and brightness can be controlled with a simple configuration. Visibility can be maintained.

  According to the embodiment described above, the following organic EL panel driving device 1 and organic EL panel driving method can be obtained.

(Additional remark 1) In the organic EL panel drive device 1 provided with the organic EL panel 4 and the power supply circuit 2 that supplies a predetermined voltage to the organic EL panel 4,
The luminance of the organic EL panel 4 is set according to the lighting rate of the pixel when the content to be displayed on the organic EL panel 4 is displayed so that the voltage supplied to the organic EL panel 4 is within the maximum voltage supplied by the power supply circuit 2. A microcomputer 6 pre-determined and stored for each content,
When displaying content, the microcomputer 6 that reads the luminance stored in advance in the microcomputer 6 for each content and changes the organic EL panel 4 to the luminance;
An organic EL panel driving device 1 comprising:

  According to this organic EL panel drive device, visibility can be maintained even if driven without using a booster circuit. Further, since the luminance is changed to a predetermined luminance for each content, it is not necessary to always calculate the luminance, and the microcomputer 6 can have a simple configuration.

(Additional remark 2) In the driving method of the organic EL panel which supplies a predetermined voltage with the power supply circuit 2 with respect to the organic EL panel 4,
The brightness according to the lighting rate of the pixel when displaying the content to be displayed on the organic EL panel 4 is set in advance for each content so that the voltage supplied to the organic EL panel 4 is within the maximum voltage supplied by the power supply circuit 2. And a method of driving the organic EL panel, wherein the brightness is changed to a preset brightness according to the content.

  According to this organic EL panel driving method, the visibility can be maintained even if the output of the regulator is driven without increasing the voltage. In addition, since the luminance is set in advance for each content, it is not necessary to always calculate the luminance, and the control system can be configured simply.

  In addition, the Example mentioned above only showed the typical form of this invention, and this invention is not limited to an Example. That is, various modifications can be made without departing from the scope of the present invention.

1 is a block diagram of a driving device for a self-luminous display panel according to an embodiment of the present invention. It is explanatory drawing which showed the example of the content displayed on the organic electroluminescent panel. 3 is a flowchart illustrating an operation when displaying content of the driving device of the self-luminous display panel illustrated in FIG. 1. It is explanatory drawing which showed the example of the content which needs to consider distribution.

Explanation of symbols

1 Organic EL panel drive device 2 Power supply circuit (regulator)
4 Organic EL panel (Self-luminous display panel)
6 Microcomputer (luminance change means, brightness storage means)

Claims (5)

In a self-luminous display panel driving device comprising: a self-luminous display panel; and a regulator that supplies a predetermined voltage to the self-luminous display panel.
The lighting rate of the pixels when displaying the content to be displayed on the self-luminous display panel so that the voltage supplied to the self-luminous display panel is within the maximum voltage supplied by the regulator. In accordance with the brightness storage means stored in advance for each content,
When displaying the content, brightness changing means for reading the brightness stored in advance in the brightness storage means for each content and changing the self-luminous display panel to the brightness;
A drive device for a self-luminous display panel, comprising:   2. The driving device for a self-luminous display panel according to claim 1, wherein the luminance is determined so as to decrease as the lighting rate increases.   3. The self-luminous display panel driving device according to claim 1, wherein the luminance is predetermined according to a distribution of lighting pixels and the lighting rate when the content is displayed on the self-luminous display panel. .   The electronic device provided with the drive device of the self-light-emitting display panel as described in any one of Claims 1 thru | or 3. In a driving method of a self-luminous display panel that supplies a predetermined voltage with a regulator to the self-luminous display panel,
The brightness corresponding to the lighting rate of the pixel when displaying the content to be displayed on the self-light-emitting display panel is set in advance for each content so that the voltage supplied to the self-light-emitting display panel is within the maximum voltage supplied by the regulator. When the content is set and displayed, the self-luminous display panel is changed to a predetermined luminance according to the content.

Images