Drive method of an electro-optical device, a drive circuit and an electro-optical device and electronic apparatus

• US 20030137499A1
• Filed: 11/20/2002
• Published: 07/24/2003
• Est. Priority Date: 12/11/2001
• Status: Active Grant

• Current Assignee: BOE Technology Group Co., Ltd.
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Iisaka, Hidehito
• Granted Patent: US 7,050,035 B2
• Time in Patent Office: Days
• US Class Current: 345/204
• CPC Class Codes: G09G 2320/0247 Flicker reduction other than flicker reduction circuits used for single beam cathode-ray tubes
• CPC Class Codes: G09G 3/20 for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
• CPC Class Codes: G09G 3/2022 using sub-frames
• CPC Class Codes: G09G 3/2025 the sub-frames having all the same time duration
• CPC Class Codes: G09G 3/28 using luminous gas-discharge panels, e.g. plasma panels
• CPC Class Codes: G09G 3/3611 Control of matrices with row and column drivers

Abstract

1 field is divided into plural sub fields on a time axis, each of which is a control unit to drive a pixel. A code storing ROM 31 stores a code to give an sub field drive pattern based on display data. With respect to adjacent pixels within a control area, a data encoder 30 writes pixel data by using a sub field drive pattern read from the code storing ROM 31 and a pattern delayed by the predetermined sub field period. Hence, adjacent pixels are driven by different sub fields drive patterns each other so that timing of flickering among adjacent pixels is differentiated. Thus, flickering can be reduced.

Claims

1. A drive circuit for an electro-optical device, including a display portion having pixels arranged in a matrix with electro-optical material of which a light transmittance ratio is changed by applying voltage, supplying on-voltage for making the light transmittance ratio be saturated, or off-voltage for making the light transmittance ratio be a non-transmissive state to the display portion, and implementing sub field drive to realize gray scale display in response to the ratio of an optical transmissive state to a non-transmissive state of the electro-optical material per unit time and time ratio, comprising;

a first pixel driving means, driving each of the pixels with each sub field as a unit of control that is formed by dividing a field into plural portions on a time axis, and driving one of the pixels located at a predetermined position in an image by a first sub field drive pattern that is an arranged pattern of a sub field of applying the off-voltage and a sub field of applying the on-voltage; and

a second pixel driving means driving the pixel with each sub field as a unit of control that is formed by dividing a field into plural portions on a time axis, and driving another of pixels adjacent to the pixel located at the predetermined position in an image by at least one second sub field drive pattern differentiated from the first sub field drive pattern;

2. A drive circuit for an electro-optical device according to claim 1, wherein;

the second pixel driving means drives the another pixel adjacent to the pixel located at the predetermined position in an image with the second sub field drive pattern by starting sub field drive based on the first sub field drive pattern, by means that start timing is differentiated by term of integral multiple of a sub field period from start timing of the sub field drive to the pixel located at a predetermined position in an image by the first driving means.

3. A drive circuit for an electro-optical device according to claim 1, wherein;

the second sub field drive pattern is obtained by delaying the first sub field drive pattern by a predetermined number of sub field periods on a time axis.

4. A drive circuit for an electro-optical device according to claim 1, wherein;

the first and the second sub field drive patters are stored in a memory.

5. A drive circuit for an electro-optical device according to claim 1, wherein;

the first and the second pixel driving means drive each of the pixels with control area unit of predetermined numbers of pixels by using the first and the second sub field drive patterns.

6. A drive circuit for an electro-optical device according to claim 1, wherein;

the first and the second pixel driving means set the sub field period to be shorter than saturation response time when transmittance ratio of the electro optic material is saturated in response to the applied on-voltage.

7. A drive circuit for an electro-optical device according to claim 1, wherein;

the first and the second pixel driving means set the sub field period to be shorter than non-transmissive response time when transmittance ratio of the electro optical material is transferred from a saturated state to a non-transmissive state in response to the applied off-voltage.

8. A drive circuit for an electro-optical device according to claim 1, wherein;

the first and the second pixel driving means apply the on-voltage to the electro-optical material during continuous or discontinuous sub fields so that an integral value of the transmissive state of the electro-optical material in the field period is in response to display data.

9. A drive circuit for an electro-optical device according to claim 1, wherein;

the first and the second pixel driving means apply the on-voltage to the electro-optical material during the sub field period at the former end part of the field period intensively.

10. A drive circuit of an electro-optical device according to claim 1, wherein;

the first and the second pixel drive means apply the off-voltage to the electro-optical material during the sub field period at the latter end part of the field period intensively.

11. A drive circuit of an electro-optical device according to claim 1, wherein;

a plurality of sub fields within each field is set to have the almost equivalent time width each other.

12. A drive circuit of an electro-optical device according to claim 1 wherein, a plurality of sub fields within each field is set to have plural different time widths each other.

15. An electro-optical device being provided with a driving circuit of an electro-optical device according to any one of claim 1 to 12.

16. An electronic apparatus being provided with an electro-optical device according to claim 15.

13. A method of driving an electro-optical device including a display portion having pixels arranged in a matrix with electro-optical material of which a light transmittance ratio is changed by applying voltage, supplying on-voltage for making the light transmittance ratio be saturated, or off-voltage for making the light transmittance ratio be a non-transmissive state to the display portion, and implementing sub field drive to realize gray scale display in response to the ratio of an optical transmissive state to a non-transmissive state of the electro-optical material per unit time and time ratio;

comprising;

a process of driving the pixel with each sub field as a unit of control that is formed by dividing a field into plural portions on a time axis; and

a process of driving pixels, located adjacently each other in an control area that is composed of predetermined numbers of pixels, by sub field driving with changing arranged pattern of the sub field of applying the off-voltage and the sub field of applying the on-voltage.

14. A method of driving an electro-optical device including a display portion having pixels arranged in a matrix with electro-optical material of which an light transmittance ratio is changed by applying voltage, supplying on-voltage for making the light transmittance ratio be saturated, or off-voltage for making the light transmittance ratio be a non-transmissive state to the display portion, and implementing sub field drive to realize gray scale display in response to the ratio of an optical transmissive state to a non-transmissive state of the electro-optical material per unit time and time ratio;

comprising;

a first process of driving the pixel with each sub field as a unit of control that is formed by dividing a field into plural portions on a time axis and driving the pixel located at a predetermined position in an image by a first sub field drive pattern that is an arranged pattern of a sub field of applying the off-voltage and a sub field of applying the on-voltage; and

a second process of driving the pixel with a sub field as a unit of control that is formed by dividing a field into plural portions on a time axis and driving a pixel adjacent to the pixel located at a predetermined position in an image by at least one second sub field drive pattern differentiated from the first sub field drive pattern.