Display device

• US 20030020699A1
• Filed: 04/17/2002
• Published: 01/30/2003
• Est. Priority Date: 07/27/2001
• Status: Active Grant

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Watanabe, Yasuyuki, Sakamoto, Akira, Nakatani, Hironori
• Granted Patent: US 7,123,246 B2
• Time in Patent Office: Days
• US Class Current: 345/204
• CPC Class Codes: G06F 3/1415 with means for detecting differences between the image stored in the host and the images displayed on the displays
• CPC Class Codes: G09G 2300/0408 Integration of the drivers onto the display substrate
• CPC Class Codes: G09G 2310/06 Details of flat display driving waveforms
• CPC Class Codes: G09G 2320/0247 Flicker reduction other than flicker reduction circuits used for single beam cathode-ray tubes
• CPC Class Codes: G09G 2320/103 Detection of image changes, e.g. determination of an index representative of the image change
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 2340/0435 Change or adaptation of the frame rate of the video stream
• CPC Class Codes: G09G 3/3611 Control of matrices with row and column drivers
• CPC Class Codes: G09G 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence

Abstract

The invention provides a display device which is capable of adjusting the image refresh rate to an optimal value regardless of the type of image data, and thus has low power consumption. The display device includes a liquid crystal panel for displaying images, a liquid crystal controller for refreshing images displayed in the liquid crystal panel according to an image data signal, and a CPU for inputting the image data signal to the liquid crystal controller. In the display device, the CPU has a discrimination section for discriminating whether the image data is a moving image or a still image based on an input interval of the image data from the CPU to the liquid crystal controller, and the liquid crystal controller has an image refresh demand signal generation circuit for changing the image refresh rate of the liquid crystal panel based on the result of discrimination by the CPU.

Claims

1. A display device comprising:

a capacitive display element which displays an image;

a display control section which refreshes an image displayed in the capacitive display element according to image data;

an image data input section which inputs the image data to the display control section;

a discrimination section which discriminates a type of the image data based on an input interval of the image data from the image data input section to the display control section; and

a refresh rate control section which changes an image refresh rate of the image in the capacitive display element, according to a result of discrimination by the discrimination section.

2. The display device set forth in claim 1, wherein:

the discrimination section discriminates whether the image data is a still image or a moving image based on the input interval of the image data from the image data input section to the display control section.

3. The display device set forth in claim 2, wherein:

the discrimination section discriminates the image data as a still image when the input interval is equal to or longer than a predetermined interval, and the discrimination section discriminates the image data as a moving image when the input interval is shorter than the predetermined interval.

4. The display device set forth in claim 2, wherein:

the refresh rate control section is adopted so that, when the image data is discriminated as a moving image by the discrimination section, the image refresh rate of the capacitive display element becomes equal to or greater than an input rate of the image data from the image data input section to the display control section.

5. The display device set forth in claim 2, wherein:

the refresh rate control section determines the image refresh rate of the capacitive display element based on an image holding characteristic of the capacitive display element for holding the displayed image, when the image data is discriminated as a still image by the discrimination section.

6. The display device set forth in claim 1, comprising:

an output section which outputs an image signal for refreshing the images displayed in the capacitive display element at certain intervals;

an output control section which transfers the image signal outputted from the output section to the capacitive display element while thinning out part of the image signal; and

a control data generation section which generates control data which indicates integer values m and n of an integer ratio m/n which is a ratio between a number of thin-out of the image signal and a number of transfers of the image signal, in the output control section, based on a result of discrimination by the discrimination section,

wherein;

the refresh rate control section comprises a timing instructing section which instructs a transfer timing of the image signal to the output control section according to the control data.

7. The display device set forth in claim 6, wherein:

the output control section transfers and thins out the image signal in such a manner that an image transfer period and an image thin-out period are provided alternately.

8. The display device set forth in claim 6, wherein:

the refresh rate control section transfers the image signal one after another 2 times or more.

9. The display device set forth in claim 6, wherein:

the timing instructing section outputs an image refresh demand signal to the output control section based on the control data, and

the image refresh demand signal becomes active when the image signal is transferred, and becomes inactive when the image signal is thinned out.

10. The display device set forth in claim 9, wherein:

a driving voltage is applied to the capacitive display element when the image refresh demand signal is active, and a driving voltage is not applied to the capacitive display element when the image refresh demand signal is inactive.

11. The display device set forth in claim 9, wherein:

the timing instructing section outputs an active image refresh demand signal.

12. The display device set forth in claim 11, wherein:

the timing instructing section has a mask function which masks the active image refresh demand signal.

13. The display device set forth in claim 6, wherein:

the display control section comprises a storage section for storing the image data.

14. The display device set forth in claim 13, wherein:

the display control section independently controls the input interval and an output interval of the image data.

15. The display device set forth in claim 6, wherein:

the refresh rate control section further comprises an operation control section which stops operation of the timing instructing section, based on at least either one of the integer values m and n when the integer ratio m/n is at or smaller than a predetermined value, so as to directly transfer the image signal outputted from the output section to the capacitive display element.

16. The display device set forth in claim 15, wherein:

the refresh rate control section starts operation of the timing instructing section according to the operation control section when the integer ratio m/n is greater than the predetermined value, so as to thin out the image signal.