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

• US 7,050,035 B2
• Filed: 11/20/2002
• Issued: 05/23/2006
• 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
• Primary Examiner(s): Awad, Amr A.
• Assistant Examiner(s): Kovalick, Vincent E.
• Application Number:
  US10/299,844
• Publication Number:
  US 20030137499A1
• Time in Patent Office: 1,280 Days
• Field of Search: 345/55, 345/60, 345/63, 345/68, 345/89, 345/100, 345/103, 345/204, 345/210, 345/690, 345/691, 345/99, 315/169.1, 349/77, 349/83
• US Class Current: 345/99
• 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

A display provided to reduce flicker by a driving method of using a sub field drive.

One 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 stores a code to give a sub field drive pattern based on display data. With respect to adjacent pixels within a control area, a data encoder writes pixel data by using a sub field drive pattern read from the code storing ROM 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.

Claims

1. A drive circuit for an electro-optical device, including a display portion having pixels arranged in a matrix and having a light transmittance ratio changed by applying voltage, supplying on-voltage to make the light transmittance ratio be saturated, or off-voltage to make 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 a ratio of an optical transmissive state to a non-transmissive state of the electro-optical material per unit time, comprising:

a first pixel driving device, 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;

a second pixel driving device, 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 an least one second sub field drive pattern differentiated from the first sub field drive pattern; and

a timing of starting a field to supply the on-voltage or the off-voltage to the pixel is shifted regarding each adjacent pixel.

2. The drive circuit for an electro-optical device according to claim 1, the second pixel driving device, driving 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 differentiating the start timing 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 device.

3. The drive circuit for an electro-optical device according to claim 1, the second sub field drive pattern being obtained by delaying the first sub field drive pattern by a predetermined number of sub field periods on a time axis.

4. The drive circuit for an electro-optical device according to claim 1, the first and the second sub field drive patterns being stored in a memory.

5. The drive circuit for an electro-optical device according to claim 1, the first and the second pixel driving devices driving each of the pixels with a control area unit of predetermined numbers of pixels by using the first and the second sub field drive patterns.

6. The drive circuit for an electro-optical device according to claim 1, the first and the second pixel driving devices applying the on-voltage to the electro-optical material during the sub field period at the former end part of the field period intensively.

7. The drive circuit of an electro-optical device according to claim 1, the first and second pixel drive devices applying the off-voltage to pixels during the sub field period at the latter end part of the field period intensively.

8. The drive circuit of an electro-optical device according to claim 1, a plurality of sub fields within each field being set to have the almost equivalent time width.

9. The drive circuit of an electro-optical device according to claim 1 a plurality of sub fields within each field being set to have plural different time widths.

10. An electro-optical device being provided with the driving circuit of an electro-optical device according to claim 1.

11. An electronic apparatus being provided with the electro-optical device according to claim 10.

12. The drive circuit of an electro-optical device according to claim 1, a sub field drive pattern is changed in order to differentiate timing flickering every unit of a predetermined display area regarding adjacent pixels.

13. A drive circuit for an electro-optical device, including a display portion having pixels arranged in a matrix and having a light transmittance ratio changed by applying voltage, supplying on-voltage to make the light transmittance ratio be saturated, or off-voltage to make 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 a ratio of an optical transmissive state to a non-transmissive state of the electro-optical material per unit time, comprising:

a first pixel driving device, 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;

a second pixel driving device, 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; and

the first and the second pixel driving devices setting the sub field period to be shorter than saturation response time when transmittance ratio of the pixels is saturated in response to the applied on-voltage.

14. A drive circuit for an electro-optical device, including a display portion having pixels arranged in a matrix and having a light transmittance ratio changed by applying voltage, supplying on-voltage to make the light transmittance ratio be saturated, or off-voltage to make 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 a ratio of an optical transmissive state to a non-transmissive state of the electro-optical material per unit time, comprising:

a first pixel driving device, 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;

a second pixel driving device, 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; and

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

15. A drive circuit for an electro-optical device, including a display portion having pixels arranged in a matrix and having a light transmittance ratio changed by applying voltage, supplying on-voltage to make the light transmittance ratio be saturated, or off-voltage to make 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 a ratio of an optical transmissive state to a non-transmissive state of the electro-optical material per unit time, comprising:

a first pixel driving device, 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;

a second pixel driving device, 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; and

the first and the second pixel driving devices applying the on-voltage to pixels during continuous or discontinuous sub fields so that an integral value of the transmissive state of the pixels in the field period in response to display data.

16. A method of driving an electro-optical device including a display portion having pixels arranged in a matrix and having a light transmittance ratio changed by applying voltage, supplying on-voltage to make the light transmittance ratio be saturated, or off-voltage to make 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, comprising:

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;

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; and

a timing of starting a field to supply the on-voltage or the off-voltage to the pixel is shifted regarding each adjacent pixel.

17. A method of driving an electro-optical device including a display portion having pixels arranged in a matrix and having a light transmittance ratio changed by applying voltage, supplying on-voltage to make the light transmittance ratio be saturated, or off-voltage to make 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, comprising:

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;

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; and

the first and the second pixel driving devices setting the sub field period to the shorter than saturation response time when transmittance ratio of the pixels is saturated in response to the applied on-voltage.

18. A method of driving an electro-optical device including a display portion having pixels arranged in a matrix and having a light transmittance ratio changed by applying voltage, supplying on-voltage to make the light transmittance ratio be saturated, or off-voltage to make 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, comprising:

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 portion of a sub field of applying the off-voltage and a sub field of applying the on-voltage;

driving the pixel with a sub field as a unit of control that is formed by dividing a field into plurality 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; and

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

19. A method of driving an electro-optical device including a display portion having pixels arranged in a matrix and having a light transmittance ratio changed by applying voltage, supplying on-voltage to make the light transmittance ratio be saturated, or off-voltage to make 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, comprising:

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;

driving the pixel with a sub field as a unit of control that is formed by dividing a field into plurality 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; and

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