JP2007178481A - Display device and display method - Google Patents

Abstract

The present invention suppresses local deterioration of a pixel while maintaining practicality, and maintains a good display quality.
A light emission history of each pixel of a display unit configured by a self-light emitting element is stored (step S3), and a user is notified of an image change time of the display unit based on the light emission history (step S3). Step S5).
[Selection] Figure 3

Description

  The present invention relates to a display device and a display method.

  In recent years, display devices using organic EL (electro-luminescence) elements as pixels have been developed. As the organic EL element is driven at a high luminance or for a long time, the deterioration proceeds. Pixels with deteriorated organic EL elements tend to have lower luminance. For example, if the deterioration of a specific pixel has progressed as a result of continuing to display the same image for a long period of time, the luminance is locally lowered, and the display quality of the entire screen is deteriorated.

As a conventional technique for coping with such a problem, there is one disclosed in Patent Document 1. In this portable terminal device including a display device and an operation panel, when the operation panel has not been operated for a predetermined time or more, the bits of display information composed of binary signals having a plurality of bits are inverted or the luminance is reduced. It is shifted by several bits in the direction of lowering.
JP 2002-268601 A

  In the technique described in the above publication, for example, when a natural image such as a landscape photograph is displayed, if the bit inversion is performed, the color of the image changes, so the user may feel uncomfortable. When the brightness is lowered and the brightness is lowered, the screen becomes difficult to see, so that it is not practical.

  The present invention has been made in view of the above-described circumstances, and an object thereof is to suppress local deterioration of a pixel while maintaining practicality and to maintain good display quality.

  In order to solve the above problem, in the present invention, as a first means related to a display device, a display means in which each pixel is constituted by a self-luminous element, a history storage means for storing a light emission history of each pixel, A change means for changing the image of the display means based on the light emission history is adopted.

  Further, as a second means related to the display device, a display means in which each pixel is constituted by a self-luminous element, a history storage means for storing a light emission history of each pixel, and a display means based on the light emission history. A notification means for notifying the user of the image change time is adopted.

  As a third means related to the display device, in the first means, an image storage means for storing a plurality of types of images that can be displayed on the display means and / or a plurality of types of arrangements of various icons displayed on the display means. And further comprising a configuration storage means for storing, the change means when changing the image of the display means based on the light emission history, and a plurality of types of images stored in the image storage means and / or the configuration storage means, and Among the arrangements of the various icons, one that is changed to an optimum one for alleviating the unevenness of the deterioration state of each pixel is employed.

  As a fourth means related to the display device, in the second means, an image storage means for storing a plurality of types of images that can be displayed on the display means and / or a plurality of types of arrangements of various icons displayed on the display means. The storage device further includes a storage device for storing, and the notification device is stored in the image storage device and / or the configuration storage device when notifying the user of the change time of the image on the display device based on the light emission history. Among the arrangements of a plurality of types of images and / or various icons, the one that notifies the user of the optimal one for alleviating the bias of the deterioration state of each pixel is adopted.

  As a fifth means related to the display device, in any one of the first to fourth means, the light emission history is information based on the lighting time of each pixel.

  As a sixth means related to the display device, in any one of the first to fifth means, the history storage means stores the light emission history for each color element constituting each pixel.

  Furthermore, in the present invention, as a first means related to the display method, a light emission history of the pixel in each pixel of the display unit configured by self-luminous elements is stored, and an image of the display unit is stored based on the light emission history. The method to change was adopted.

  Further, as a second means related to the display method, a light emission history of the pixel in each pixel of the display unit configured by the self-light emitting element is stored, and the change time of the image on the display unit is determined based on the light emission history. The method of notifying to was adopted.

  As a third means related to the display method, when the first means stores a plurality of types of images and / or various icon arrangements and changes the image based on the light emission history, the plurality of types of images and / or Alternatively, a method of changing the arrangement of various icons to an optimum one to alleviate the unevenness of the deterioration state of each pixel is adopted.

As a fourth means related to the display method, in the second means, a plurality of types of image and / or various icon arrangements are stored,
When notifying the user of the change timing of the image based on the light emission history, an optimal one for mitigating the bias of the deterioration state of each pixel from among a plurality of types of images and / or various icon arrangements A method of notifying the user was adopted.

  As a fifth means related to the display method, in any one of the first to fourth means, the light emission history is information based on the lighting time of each pixel.

  As a sixth means related to the display method, a method of storing the light emission history for each color element of the self-light-emitting element in any one of the first to fifth means is adopted.

  According to the present invention, since the image to be displayed on the display device is changed (or notified to be changed) based on the light emission history of each pixel, the deterioration is averaged before the difference in deterioration of each pixel becomes fatal. (Or prompt the user to average the degradation). Therefore, local deterioration of the pixels can be suppressed and display quality can be kept good.

  Hereinafter, a mobile phone which is an embodiment of a display device of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a mobile phone 1 (display device) in the present embodiment. The mobile phone 1 includes a control unit 2, a ROM 3, a RAM 4, an operation unit 5, an EL display unit 6, an EL display driving circuit 7, a display information storage unit 8, a pixel deterioration information storage unit 9, An image information analysis unit 10, a transmission / reception unit 11, an antenna 12, a speaker 13, and a microphone 14 are provided.

The control unit 2 comprehensively controls each unit based on various programs stored in the ROM 3. The RAM 4 temporarily stores various calculation results and various information used for the calculations performed by the control unit 2.
In the ROM 3, in addition to various programs, various types of wallpaper images that can be displayed on the EL display unit 6 (shown in FIG. 2), various alert messages displayed on the EL display unit 6 (as shown in FIG. 4 described later) ), Various style sheets (such as those shown in FIGS. 6 and 7 described later) for setting the size and arrangement of various icons displayed on the EL display unit 6 are stored.

The EL display unit 6 has a screen in which each pixel is configured by an organic EL element (self-emitting element), and is driven by an EL display drive circuit 7. The EL display drive circuit 7 drives the EL display unit 6 based on the operation amount generated by the control unit 2 based on the image displayed on the EL display unit 6.
Here, each pixel of the EL display unit 6 is composed of sub-elements configured by three types of self-luminous elements (color elements) that emit three primary colors of light of R (red), G (green), and B (blue). Has pixels. The operation amount is given for each subpixel.

The display information storage unit 8 is used when an image being displayed on the EL display unit 6 is saved, and temporarily stores image data.
The pixel deterioration information accumulation unit 9 calculates the product of the operation amount given to the sub-pixel of each pixel and the drive duration (lighting time) at the operation amount for each sub-pixel of each pixel, and combines it with the past amount. And accumulated as deterioration information indicating the deterioration state. The calculation formula is as shown in the following formula (1).

  Deterioration information = Deterioration information at the time of previous calculation + Deterioration coefficient × Drive duration × Subpixel value (1)

The sub-pixel value in the above formula (1) is a value that is given to each of the R, G, and B sub-pixels and specifies the intensity of light in 256 levels from 0 to 255. By specifying the stage of each sub-pixel, the emission color and luminance of the pixel are specified. The luminance referred to here is the intensity of light that the pixel should output when the subpixel value is given when the pixel is not deteriorated at all. Since the actual pixel is not deteriorated at all, the intensity of light output from the actual pixel is generally smaller than the luminance specified here.
Further, the deterioration coefficient in the above equation (1) is a value set for each sub-pixel, and is a value for absorbing the difference in ease of deterioration of each sub-pixel. For example, assuming that the R sub-pixel is likely to deteriorate by 20% and the G sub-pixel is difficult to deteriorate by 20% with respect to the B sub-pixel, the deterioration coefficient applied to the B sub-pixel is calculated by the deterioration coefficient. Is 1 and the degradation coefficient is 1.2 in the degradation information calculation formula applied to the R subpixel, and the degradation coefficient is 0.8 in the degradation information calculation formula applied to the G subpixel. The weights of deterioration information for all colors are equal.
If there is no difference in the ease of deterioration of each sub-pixel, all the deterioration coefficients may be set to 1, or the deterioration coefficients may not be used.

  Here, the ROM 3 is a value that can be taken by the deterioration information calculated by the above equation (1) and stores a threshold value for each predetermined interval.

The pixel information analysis unit 10 analyzes the operation amount when the wallpaper image or style sheet stored in the ROM 3 is applied to the EL display unit 6, and further reduces the bias of the deterioration state of each pixel of the EL display unit 6. Rank wallpaper images or style sheets in the order that they can.
For example, it is assumed that the image D is currently selected from the wallpaper images shown in FIG. In the image D, two “stars” and “mountains” and “night sky” are drawn. The brightness of each part is the highest in the “star” part, followed by the two “mountains”, and the lowest in the “night sky”. In the image A, one “mountain” having the same luminance as that of the image D and “night sky” are drawn. In the image B, “stars” and “night sky” having the same luminance as those in the image D are drawn. In the image C, two “mountains” and “night sky” having the same luminance as those of the image D are drawn. In this case, among the pixels of the EL display unit 6 in which the image D is selected as the wallpaper image, the fastest deterioration is the portion where the “star” having the highest luminance is displayed. 6 is an image A that has no “star” and a small “mountain” display area, then image C, image B, and finally the image. D.

The operation unit 5 includes keys and the like for accepting operations by the user, and operation information input by the operation unit 5 is output to the control unit 2.
The transmission / reception unit 11 communicates with the base station via the antenna 12 such as a telephone call. The speaker 13 sounds the voice of the other party received from the base station. The user's voice captured by the microphone 14 is transmitted to the call partner via the base station.

FIG. 3 is a flowchart showing a flow of a notification program stored in the ROM 3 and executed by the control unit 2.
When the control unit 2 outputs an operation amount based on an image to be displayed on the EL display unit 6 to the EL display drive circuit 7, the control unit 2 also outputs the same operation amount to the display information storage unit 8. The display information storage unit 8 stores the operation amount and measures the time from when the operation amount is input until the next operation amount is input, that is, the drive duration time. The control unit 2 acquires the operation amount and the drive duration time stored in the display information storage unit 8 as the light emission history of the pixel (step S1), and calculates deterioration information according to the equation (1) for each sub-pixel of each pixel. (Step S2), it accumulates in the pixel deterioration information accumulation unit 9 (Step S3).
Next, the control unit 2 determines whether or not each deterioration information exceeds a threshold value stored in the ROM 3 (step S4). If not, the control unit 2 returns to S1. This is notified (step S5).

  The notification to the user is performed, for example, by displaying an alert message as shown in FIG. When the user presses an “OK” button in accordance with this alert message, a transition is made to a selection screen as shown in FIG. In this selection screen, selectable images are introduced in the order in which the bias of the deterioration state of each pixel of the EL display unit 6 can be further relaxed based on the ranking based on the analysis result performed by the pixel information analysis unit 10. Is done. That is, if the image D is currently selected, as described above, it is the image A that is most suitable for alleviating the bias in the deterioration state of each pixel, and then the image C, the image B, and finally That is, the image D.

The criterion for determining Yes in step S4 is
(1) Even one deterioration information accumulated for each sub-pixel of each pixel exceeds a threshold value. (2) The number of sub-pixels or pixels whose deterioration information exceeds a threshold value may be a predetermined value or more. In the case of (2), even if the bias is not alleviated for all the subpixels whose deterioration information exceeds the threshold by changing the wallpaper, it is only necessary to reduce the bias for the majority. In this case, the ranking of the images by the pixel information analysis unit 10 is performed so as to increase the ranking of the subpixels or pixels having a large number of pixels that can reduce the bias.
Further, since the deterioration information does not decrease even if its value increases, once the notification is given to the user in step S5, the threshold value is changed to a higher value in the next step S4.
Furthermore, although the expression (1) is given as an example of the expression for calculating the deterioration information, according to this expression, the value of the deterioration information becomes too large as time passes and cannot be stored in the pixel deterioration information accumulating unit 9. If there is a possibility, the deterioration information may be normalized to take a value in a certain range and stored in the pixel deterioration information storage unit 9 instead of the value as the expression (1).

Further, if the above process is performed every predetermined time, the elapsed time after the previous calculation may be used in place of the drive duration in Expression (1).
Further, in step S5, instead of notifying the user of the wallpaper replacement time, the wallpaper may be automatically replaced. In other words, assuming that the image D is currently selected, the image A (the “mountain” having the highest emission luminance and the next “mountain” having the highest emission luminance is eliminated. (The display area is small) may be automatically set as wallpaper. In this case, the notification program in FIG. 3 is a change program.

  By the way, various icons such as remaining battery level, radio wave intensity, e-mail notification, time, and soft keys are almost always displayed on the EL display unit 6. A style sheet as shown in FIG. 6 that defines the display positions and sizes of these icons is stored in the ROM 3 as described above. FIG. 7 shows the application state of each style sheet. FIG. 6 (a) is shown in FIG. 7 (a), FIG. 6 (b) is shown in FIG. 7 (b), and FIG. Respectively.

  FIG. 8 is a flowchart showing a flow of a program stored in the ROM 3 and executed by the control unit 2. The image information analysis unit 10 generates an image obtained by combining the image currently used for the wallpaper and each of the style sheets (step S11), and the combined image generated in S11 is obtained from the information in the image deterioration information storage unit 9. It is analyzed whether or not it is suitable for alleviating the bias of the deteriorated state (step S12). Then, the control unit 2 rearranges the list of style sheets based on the analysis result of the image information analysis unit 10 (step S13), and the rearranged list of style sheets on the EL display unit 6 as shown in FIG. Display and prompt the user to select (step S14).

  Since the various icons are displayed in a state that is easily caught by the user's eyes, they are often colored to be easily distinguished from the background. For example, in the style sheet as shown in FIG. 7, when the style C is applied when the deterioration of the pixel at the center of the screen of the EL display unit 6 is advanced as compared with the surrounding area, the style C has a dark color (dark color). Since the time is displayed, it is possible to alleviate the bias of the deterioration state. Similarly, the style B is suitable when the upper right pixel has been deteriorated.

  According to such a configuration, when each pixel of the EL display unit 6 deteriorates as the usage time of the mobile phone 1 elapses, even if the deterioration state of each pixel is biased, the bias is not generated. Before it becomes fatal, the user is encouraged to use an image that can alleviate the bias of the deterioration state of each pixel as wallpaper, and various icons are placed using a style sheet that can reduce the bias of the deterioration state of each pixel. Various icons can be arranged using a style sheet that can control the display of images that can reduce the bias of the deterioration state of each pixel as wallpaper, or that can reduce the bias of the deterioration state of each pixel. Since it is controlled to change, local deterioration of the pixel can be suppressed and the display quality of the EL display unit 6 can be kept good.

It is a block diagram which shows the structure of the mobile telephone in one Embodiment of this invention. It is a front view of the display means which shows the example of the image for wallpaper with which the mobile telephone in one Embodiment of this invention is provided. It is a flowchart which shows the flow of the process which the mobile telephone in one Embodiment of this invention performs. It is a front view of the display means which shows the example of a display of the mobile telephone in one Embodiment of this invention. It is a front view of the display means which shows the example of a display of the mobile telephone in one Embodiment of this invention. It is a schematic diagram of the table which shows the example of the style sheet with which the mobile telephone in one Embodiment of this invention is provided. It is a front view of the display means which shows the example of a display at the time of applying the style sheet with which the mobile telephone in one embodiment of the present invention is provided. It is a flowchart which shows the flow of the process which the mobile telephone in one Embodiment of this invention performs. It is a front view of the display means which shows the example of a display of the mobile telephone in one Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Mobile telephone (display apparatus), 2 ... Control part (control means), 3 ... ROM (image storage means, structure storage means), 4 ... RAM, 5 ... Operation part, 6 ... EL display part (display means), DESCRIPTION OF SYMBOLS 7 ... EL display drive circuit (drive means), 8 ... Display information storage part, 9 ... Pixel deterioration information storage part (history storage means), 10 ... Image information analysis part, 11 ... Transmission / reception part, 12 ... Antenna, 13 ... Speaker, 14 ... Microphone

Claims (12)

Display means in which each pixel is constituted by a self-luminous element;
History storage means for storing a light emission history of each pixel;
A display device comprising: changing means for changing an image of the display means based on the light emission history. Display means in which each pixel is constituted by a self-luminous element;
History storage means for storing a light emission history of each pixel;
A display device comprising: notification means for notifying a user of an image change time of the display means based on the light emission history. Image storage means for storing a plurality of types of images that can be displayed on the display means and / or configuration storage means for storing a plurality of types of arrangements of various icons displayed on the display means;
When changing the image of the display unit based on the light emission history, the changing unit selects from among a plurality of types of images and / or various icon arrangements stored in the image storage unit and / or the configuration storage unit. The display device according to claim 1, wherein the display device is changed to an optimum one to alleviate the unevenness of the deterioration state of each pixel. Image storage means for storing a plurality of types of images that can be displayed on the display means and / or configuration storage means for storing a plurality of types of arrangements of various icons displayed on the display means;
When the notification means notifies the user of the change timing of the image on the display means based on the light emission history, a plurality of types of images and / or various icons stored in the image storage means and / or the configuration storage means. 3. The display device according to claim 2, wherein a user is notified of an optimal arrangement for alleviating a bias in a deterioration state of each of the pixels.   The display device according to claim 1, wherein the light emission history is information based on a lighting time of each pixel.   The display device according to claim 1, wherein the history storage unit stores the light emission history for each color element constituting each pixel.   A display method characterized by storing a light emission history of each pixel of a display unit configured by a self-light emitting element, and changing an image of the display unit based on the light emission history.   A display method characterized by storing a light emission history of each pixel of a display unit configured by a self-light-emitting element, and notifying a user of an image change time of the display unit based on the light emission history.   When a plurality of types of image and / or various icon arrangements are stored and the image is changed based on the light emission history, the deterioration state of each pixel is biased out of the plurality of types of image and / or various icon arrangements. The display method according to claim 7, wherein the display method is changed to an optimum one for relaxing the image. Stores multiple types of image and / or various icon arrangements,
When notifying the user of the change timing of the image based on the light emission history, an optimal one for mitigating the bias of the deterioration state of each pixel from among a plurality of types of images and / or various icon arrangements The display method according to claim 8, wherein the notification is made to a user.   The display method according to claim 7, wherein the light emission history is information based on a lighting time of each pixel.   The display method according to claim 7, wherein the light emission history is stored for each color element of the self light emitting element.

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