Display apparatus and method for driving display panel

• US 8,259,039 B2
• Filed: 11/23/2010
• Issued: 09/04/2012
• Est. Priority Date: 11/26/2009
• Status: Expired due to Fees

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Abe, Naoto
• Primary Examiner(s): DINH, DUC Q
• Application Number:
  US12/952,468
• Publication Number:
  US 20110122110A1
• Time in Patent Office: 651 Days
• Field of Search: 345 60- 69, 345 76- 82, 345/87, 345/98, 345/99, 345/100, 345/101, 345/102, 345/73, 345/74.1, 345/75.1, 345/75.2, 345/690, 345/204
• US Class Current: 345/74.1
• CPC Class Codes: G09G 2320/0606 Manual adjustment
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• CPC Class Codes: G09G 2360/144 the light being ambient light
• CPC Class Codes: G09G 3/2081 with combination of amplitude modulation and time modulation space and time error diffusion G09G3/2066
• CPC Class Codes: G09G 3/22 using controlled light sources
• CPC Class Codes: G09G 3/3216 using a passive matrix
• CPC Class Codes: G09G 3/3622 using a passive matrix G09G3/3674 - G09G3/3696 take precedence

Abstract

A difference between the black level potential V_B and the white level potential V_W in the effective bright environment is smaller than a difference between the black level potential V_B and the white level potential V_W in the effective dark environment, and the black emission luminance in the effective bright environment is lower than or equal to a diffuse reflection luminance in the effective bright environment and higher than a black emission luminance in the effective dark environment.

Claims

1. A method for driving a display panel, the display panel comprising a plurality of row wirings, a plurality of column wirings that intersect the plurality of row wirings, and a plurality of display elements each connected to one of the row wirings and one of the column wirings, a display operation being performed on a display surface of the display panel by sequentially applying a selection potential to each of the row wirings and applying, to each of the column wirings, a potential in the range from a first potential to a second potential in synchronization with the application of the selection potential to the row wiring, the display operation being performed within a range of an emission luminance of the display element which is connected to one of the row wirings having the applied selection potential, the range of the emission luminance being higher than or equal to an emission luminance obtained when the first potential is applied to one of the column wirings connected to the display element and lower than or equal to an emission luminance obtained when the second potential is applied to the column wiring connected to the display element, the method comprising the step of:

making a change between (i) a first environment in which a diffuse reflection luminance occurring on the display surface when ambient light is incident on the display surface is equal to the emission luminance of the display element connected to the row wiring having the applied selection potential and the column wiring having the applied first potential and (ii) a second environment in which the diffuse reflection luminance is higher than the diffuse reflection luminance in the first environment,

wherein the change is such that (a) a difference between the first potential and the second potential in the second environment is smaller than a difference between the first potential and the second potential in the first environment, and (b) the emission luminance of the display element connected to the row wiring having the applied selection potential and the column wiring having the applied first potential in the second environment is lower than or equal to the diffuse reflection luminance in the second environment and higher than the emission luminance of the display element connected to the row wiring having the applied selection potential and the column wiring having the applied first potential in the first environment.

2. The method according to claim 1, wherein the change involves making an emission luminance of the display element connected to the row wiring having the applied selection potential and the column wiring having the applied second potential in the second environment higher than or equal to an emission luminance of the display element connected to the row wiring having the applied selection potential and the column wiring having the applied second potential in the first environment.

3. The method according to claim 1, wherein the display element connected to the row wiring having the applied selection potential performs the display operation on the display surface of the display panel with an emission luminance in accordance with the selection potential, and wherein the change involves changing the second potential and the selection potential.

4. The method according to claim 1, wherein the change is made based on at least one of the illuminance of ambient light, a clock time, and an instruction received from a user.

5. The method according to claim 1, wherein each of the plurality of display elements includes one of a cathodoluminescence element and an electroluminescence element.

6. A display apparatus comprising:

a display panel including a plurality of row wirings, a plurality of column wirings that intersect the plurality of row wirings, a plurality of display elements each connected to one of the row wirings and one of the column wirings;

a scanning circuit configured to sequentially applying a selection potential to the row wirings;

a modulation circuit configured to apply, to each of the column wirings, a potential in the range from a first potential to a second potential in synchronization with the application of the selection potential to each of the row wirings; and

a controller for changing at least one of the first potential and the second potential,

wherein an emission luminance of the display element connected to one of the row wirings having the applied selection potential is higher than or equal to an emission luminance obtained when the first potential is applied to each of the column wirings connected to the display element and lower than or equal to an emission luminance obtained when the second potential is applied to the column wiring connected to the display element, and wherein the controller makes the change between (i) a first mode in which a diffuse reflection luminance occurring on a display surface of the display panel when ambient light is incident on the display surface is equal to an emission luminance of the display element connected to the row wiring having the applied selection potential and the column wiring having the applied first potential and (ii) a second mode in which the diffuse reflection luminance is higher than the diffuse reflection luminance in the first mode, and

wherein the controller makes the change such that (a) a difference between the first potential and the second potential applied to the column wirings by the modulation circuit in the second mode is smaller than a difference between the first potential and the second potential applied to the column wirings by the modulation circuit in the first mode, and (b) the emission luminance of the display element connected to the row wiring having the applied selection potential and the column wiring having the applied first potential in the second mode is lower than or equal to the diffuse reflection luminance in the second mode and higher than the emission luminance of the display element connected to the row wiring having the applied selection potential and the column wiring having the applied first potential in the first mode.

7. The display apparatus according to claim 6, wherein the controller distinguishes the first mode and the second mode and makes the change based on a result of the distinguishing, and

wherein the controller makes the change so that the difference between the first potential and the second potential applied to the column wirings by the modulation circuit in a case where the second mode is distinguished becomes smaller than the difference between the first potential and the second potential applied to the column wirings by the modulation circuit in a case where the first mode is distinguished, and the emission luminance of the display element connected to the row wiring having the applied selection potential and the column wiring having the applied first potential in the case where the second mode is distinguished becomes lower than or equal to the diffuse reflection luminance in the case where the second mode is distinguished and higher than the emission luminance of the display element connected to the row wiring having the applied selection potential and the column wiring having the applied first potential in the case where the first mode occurs is distinguished.

8. The display apparatus according to claim 6, wherein the controller sets the emission luminance of the display element connected to the row wiring having the applied selection potential and the column wiring having the applied second potential in the second mode to a value higher than or equal to the emission luminance of the display element connected to the row wiring having the applied selection potential and the column wiring having the applied second potential in the first mode.

9. The display apparatus according to claim 6, wherein the scanning circuit applies a non-selection potential to the row wirings to which the selection potential are not applied among the plurality of row wirings,

wherein, when the modulation circuit applies, to the column wirings, a potential that is in the range from the first potential to the second potential and that is different from the first potential in synchronization with the application of the selection potential to the row wiring, the modulation circuit applies the first potential to the column wiring every time the selection potential is applied to one of the row wirings, and

wherein the number of the row wirings is greater than the square of a value obtained by dividing a difference between the selection potential and the non-selection potential by a difference between the first potential and the second potential in the first and second modes.

10. The display apparatus according to claim 6, wherein the display element connected to the row wiring having the applied selection potential has an emission luminance in accordance with the selection potential, and wherein the controller changes the second potential and the selection potential.

11. The display apparatus according to claim 6, further comprising:

at least one of an illuminance sensor configured to output illuminance data obtained in accordance with the illuminance of the ambient light and a timer configured to output clock time data obtained in accordance with a clock time,

wherein the controller makes the change between the first mode and the second mode based on at least one of the illuminance data and the clock time data.

12. The display apparatus according to claim 6, wherein each of the plurality of display elements includes one of a cathodoluminescence element and an electroluminescence element.