Driving apparatus for driving display panel

• US 6,559,603 B2
• Filed: 09/10/2001
• Issued: 05/06/2003
• Est. Priority Date: 09/08/2000
• Status: Expired due to Fees

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Pioneer Corporation, Shizuoka Pioneer Corporation
• Inventors: Iwami, Takashi
• Primary Examiner(s): Philogene, Haissa
• Assistant Examiner(s): Alemu, Ephrem
• Application Number:
  US09/948,937
• Publication Number:
  US 20020047575A1
• Time in Patent Office: 603 Days
• Field of Search: 315/169.3, 315/169.1, 315/169.4, 345/55, 345/60, 345/67, 345/68, 345/80, 345/94, 345/214, 345/212, 345/204, 345/211
• US Class Current: 315/169.1
• CPC Class Codes: G09G 2310/0213 controlling the sequence of the scanning lines with respect to the patterns to be displayed, e.g. to save power
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 3/293 for address discharge
• CPC Class Codes: G09G 3/2965 using inductors for energy recovery

Abstract

A display panel drive apparatus can reduce power consumption upon writing pixel data. The display panel drive apparatus reduces a resonance amplitude of the resonance pulse voltage source carrying the generation of the pixel data pulse while keeping maximum potential level thereof, when at least two of the supplied pixel data neighboring each other in column direction assume the same logic value as each other.

Claims

1. A drive apparatus for driving a display panel having a plurality of row electrodes and a plurality of column electrodes intersecting with said row electrodes to form capacitive light-emitting elements, by applying pixel data to said column electrodes while successively applying scan pulses to said row electrodes said pixel pulses each representing a pixel data based on an input video signal, which comprises:

a voltage source circuit for generating a resonance pulse source potential having a resonance amplitude variable to have a maximum potential level at a first predetermined potential and supplying the generated resonance pulse source potential to a voltage source line; and

a picture element data pulse generating circuit for generating said pixel data on by connecting said voltage source line with either ones of said column electrodes in accordance with said picture element data so as to cause said picture data pulse to appear on said either one of the column electrodes,

said voltage source circuit causing said resonance amplitude to decrease while keeping said maximum potential at said first predetermined potential when at least two of said pixel data neighboring each other in the column direction have the same logical value.

2. A drive apparatus according to claim 1, in which said voltage source circuit causes said resonance amplitude to decrease by such an amount proportionate to a number of neighboring pixel datas having the same logical values.

3. A drive apparatus according to claim 1, in which

said voltage source circuit includes a capacitor having one terminal thereof grounded, a first switching element and a first coil serially connected with each other between the other terminal of said capacitor and said voltage source line, a second switching element and a second coil serially connected with each other between the other terminal of said capacitor and said voltage source line, a DC voltage source generating a first potential, and a third switching element connected between said DC voltage source and said voltage source line,

said pixel data pulse generating circuit includes fourth switching elements for connecting said voltage source line with either ones of said column electrodes in accordance with a logical value of said pixel data, and fifth switching elements for grounding either one of said column electrodes in accordance with an inverse value of said pixel data.

4. A drive apparatus according to claim 1, which periodically and repeatedly performs a switch drive sequence having a first drive step for causing only said first switching element to be ON, a second drive step for causing only said third switching element to be ON, and a third drive step for causing said second switching element to be ON.

8. A drive apparatus according to claim 3, which further comprises:

a clamp circuit for causing the potential of said capacitor to become a predetermined reference potential when the potential of said capacitor exceeds said predetermined reference potential.

9. A drive apparatus according to claim 8, in which said predetermined reference potential is higher than a half of said first potential but lower than said first potential.

10. A drive apparatus according to claim 8, which further comprises:

clamp operation control means for causing said clamp circuit to change its state from an operative state to an inoperative state and vice versa.

11. A drive apparatus according to claim 10, in which said clamp operation control means determines a kind of said input video signal and causes said clamp circuit to change its state from the operative state to the inoperative state and vice versa in accordance with the determination result.

5. A drive apparatus for driving a display panel having a plurality of row electrodes and a plurality of column electrodes intersecting with said row electrodes to form capacitive light-emitting elements, by applying pixel data to said column electrodes while successively applying scan pulses to said row electrodes said pixel pulses each representing a pixel data based on an input video signal, which comprises:

a voltage source circuit including a capacitor having one terminal thereof grounded, a first switching element and a first coil serially connected to each other between the other terminal of said capacitor and said voltage source line, a second switching element and a second coil connected serially to each other between the other terminal of said capacitor and said voltage source line, a DC voltage source for generating said first potential, a third switching element connected between said DC voltage source and said voltage source line, and a variable voltage source for exerting onto other terminal of the capacitor a potential variable with a number of the pixel datas which are neighboring each other in the column direction and have the same logic values as each other; and

a pixel data pulse generating circuit including fourth switching elements for connecting said voltage source line and either ones of said column electrodes in accordance with the a logic value of said pixel data, and fifth switching elements for grounding either ones of said column electrodes of an inverse logic value of said pixel data.

6. A drive apparatus according to claim 5, in which

said variable voltage source decreases a potential to be applied to the other terminal of said capacitor when a number of the pixel data neighboring each other and having the same logic values as each other is small and increases that potential when said number is large.

7. A drive apparatus according to claim 5, in which

said variable voltage source causes the potential to be applied to the other terminal of said capacitor to vary within a range of from a half of said first potential to said first potential.