Transreflective display apparatus and driving method thereof

• US 8,237,643 B2
• Filed: 11/12/2008
• Issued: 08/07/2012
• Est. Priority Date: 11/12/2008
• Status: Active Grant

• Current Assignee: Himax Technologies Ltd. (Himax Technologies Incorporated)
• Original Assignee: Himax Technologies Ltd. (Himax Technologies Incorporated)
• Inventors: Wu, Biing-Seng, Bu, Lin-Kai, Chen, Ying-Lieh
• Primary Examiner(s): Dharia, Prabodh M
• Application Number:
  US12/269,483
• Publication Number:
  US 20100117940A1
• Time in Patent Office: 1,364 Days
• Field of Search: 345/1.3, 345/55, 345 84-103, 345/204, 345/211, 345/212, 345/581, 345/589, 345694-696, 700/21, 700/22, 700/79, 700/295, 455/1, 455/73, 455/99, 455/566
• US Class Current: 345/84
• CPC Class Codes: G09G 2300/0456 with a reflective area and a transmissive area combined in one pixel, such as in transflectance pixels
• CPC Class Codes: G09G 2320/0238 Improving the black level
• CPC Class Codes: G09G 2320/0673 for control of gamma adjustment, e.g. selecting another gamma curve
• CPC Class Codes: G09G 2360/144 the light being ambient light
• CPC Class Codes: G09G 3/3611 Control of matrices with row and column drivers

Abstract

A driving method and a transreflective display apparatus are provided herein. In the driving method, a plurality of voltage-to-transparency curves are provided. An ambient light intensity of the display apparatus is detected for determining a display mode, wherein the display mode is either a transmissive mode or a reflective mode. Next, one of the voltage-to-transparency curves is selected according to the display mode and the ambient light intensity for driving the display apparatus. Therefore, by referring a proper voltage-to-transparency curve to drive the display apparatus, the display quality of the display apparatus can be enhanced.

Claims

1. A driving method for a transreflective display apparatus, the driving method comprising:

providing a plurality of voltage-to-transparency (V-T) curves;

detecting an ambient light intensity of the display apparatus;

determining a display mode according to the ambient light intensity, wherein the display mode is either a transmissive mode or a reflective mode; and

selecting one of the V-T curves to drive the display apparatus based on the display mode and the ambient light intensity,

wherein a gamma voltage corresponding to a low gray level of the transmissive mode V-T curve is larger than a gamma voltage corresponding the same gray level of the reflective mode V-T curve.

2. The driving method as claimed in claim 1, wherein the V-T curves include a reflective mode V-T curve and a transmissive mode V-T curve.

3. The driving method as claimed in claim 2, wherein in the selecting step, the transmissive mode V-T curve is selected if the display mode is the transmissive mode.

4. The driving method as claimed in claim 2, wherein in the selecting step, the transmissive mode V-T curve is selected if the display mode is the transmissive mode, and there exists some ambient light.

5. The driving method as claimed in claim 2, wherein in the selecting step, the transmissive mode V-T curve is selected if the display mode is the transmissive mode, and the ambient light intensity is larger than a low threshold.

6. The driving method as claimed in claim 2, wherein a gamma voltage corresponding to a high gray level of the transmissive mode V-T curve is substantially equal to a gamma voltage corresponding the same gray level of the reflective mode V-T curve.

7. The driving method as claimed in claim 1, wherein each V-T curve is generated by a set of gamma voltages.

8. The driving method as claimed in claim 7, wherein the set of gamma voltages is generated by a resistor string.

9. The driving method as claimed in claim 7, wherein the set of gamma voltages is generated by a programmable gamma voltage generator.

10. A transreflective display apparatus, comprising:

a display panel, for displaying an image;

an ambient light detector, coupled to the display panel for detecting an ambient light intensity of the display apparatus, and thereby determining a display mode of the display apparatus according to the ambient light intensity, wherein the display mode is either a transmissive mode or a reflective mode;

a backlight module, for providing a backlight when the display mode is the transmissive mode;

a timing controller, coupled to the ambient light detector for selecting one of a plurality of voltage-to-transparency (V-T) curves according to the display mode and the ambient light intensity; and

a gamma voltage generator, coupled to the timing controller and controlled by the timing controller for generating a plurality of gamma voltages based on the selected V-T curve,

wherein one of the gamma voltages corresponding to a low gray level of the transmissive mode V-T curve is larger than one of the gamma voltages corresponding the same gray level of the reflective mode V-T curve.

11. The display apparatus as claimed in claim 10, wherein the ambient light detector comprises:

a photo sensor, for detecting the ambient light intensity of the display apparatus to output an electronic signal; and

a light controller, coupled to the photo sensor, for receiving the electronic signal, and converting the electronic signal into a detection signal with digital form, wherein the ambient light controller determines the display mode according to the detection signal.

12. The display apparatus as claimed in claim 10, wherein the V-T curves includes a reflective mode V-T curve and a transmissive mode V-T curve.

13. The display apparatus as claimed in claim 12, wherein the timing controller selects the transmissive mode V-T curve if the display mode is the transmissive mode.

14. The display apparatus as claimed in claim 12, wherein the timing controller selects the transmissive mode V-T curve if the display mode is the transmissive mode, and there exists some ambient light.

15. The display apparatus as claimed in claim 12, wherein the timing controller selects the transmissive mode V-T curve if the display mode is the transmissive mode, and the ambient light intensity is larger than a low threshold.

16. The display apparatus as claimed in claim 12, wherein one of the gamma voltages corresponding to a high gray level of the transmissive mode V-T curve is substantially equal to one of the gamma voltages corresponding the same gray level of the reflective mode V-T curve.