Flat display panel having internal lower supply circuit for reducing power consumption

• US 20060176248A1
• Filed: 03/01/2006
• Published: 08/10/2006
• Est. Priority Date: 11/19/1993
• Status: Active Grant

• Current Assignee: Hitachi Maxell Limited (Hitachi, Ltd.)
• Original Assignee: Hitachi, Ltd.
• Inventors: Tomio, Shigetoshi, Matsui, Naoki, Yao, Shinpei
• Granted Patent: US 7,592,976 B2
• Time in Patent Office: Days
• US Class Current: 345/60
• CPC Class Codes: G09G 2330/02 Details of power systems and of start or stop of display operation
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 2330/022 in absence of operation, e.g. no data being entered during a predetermined time
• CPC Class Codes: G09G 2330/04 Display protection
• 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 3/2927 Details of initialising
• CPC Class Codes: G09G 3/294 for lighting or sustain discharge
• CPC Class Codes: G09G 3/297 using opposed discharge type panels

Abstract

A flat display employs at least one high voltage different from logic voltages. The display has a voltage detection unit and a drive control signal control unit. The voltage detection unit is used to detect the high voltage. The drive control signal control unit is used to control drive control signals of the flat display in accordance with the detected high voltage. This arrangement eliminates charging currents that are applied to a display panel but have nothing to do on the actual displaying of data, or reactive currents due to unnecessary switching operations, thereby reducing power consumption.

Claims

1. A flat display device which employs a display high voltage for sustain discharge in addition to a logic voltage, comprising:

a first detection unit which detects a voltage value of the display high voltage;

a second detection unit which detects an externally input signal or an existence of input display data; and

a drive control signal controller which controls a drive control signal for controlling an application of a shape of drive signal to the display device, according to the detection by the first and second detection units.

2. A flat display device according to the claim 1, further comprising:

an internal power supply circuit supplied with the logic voltage and the display high voltage and, in response, outputting an address discharge pulse voltage, a write discharge pulse voltage and an erase pulse voltage; and

an internal power control unit which controls an operation of the internal power supply circuit.

3. A flat display device according to the claim 2, further comprising:

a third detection unit which detects the address discharge pulse voltage, the write discharge pulse voltage and the erase pulse voltage,

wherein the internal power control unit changes the power control signal according to the detected display high voltage, address discharge pulse voltage, write discharge pulse voltage and erase pulse voltage so as to control the application of the shape of drive signal.

4. A flat display device according to the claim 2, further comprising:

a third detection unit which detects the address discharge pulse voltage, the write discharge pulse voltage and the erase pulse voltage,

wherein the drive control signal controller changes the power control signal according to the detected display high voltage, address discharge pulse voltage, write discharge pulse voltage and erase pulse voltage so as to control the application of the shape of drive signal.

5. A flat display device according to the claim 2, wherein:

the drive control signal controller stops applying the shape of drive signal according to the drive control signal while the detected display high voltage does not reach an internally set prescribed value, and resumes applying the shape of drive signal when the detected display high voltage reaches the internally set prescribed value.

6. A flat display device according to the claim 5, wherein:

the drive control signal controller has at least first and second prescribed values, internally set for comparing with the detected display high voltage, and employs the first prescribed value while the display high voltage rises and the second prescribed value while the display high voltage falls.

7. A flat display device according to the claim 1, wherein:

the flat display device is a three electrodes surface discharge AC type plasma display device having a surface discharge structure employing wall charges as a memory medium;

the plasma display device comprises pairs of sustain discharge electrodes for sustain discharge, arranged in parallel; and

address electrodes are arranged perpendicular to the sustain electrodes,

wherein selected ones of the pairs of sustain discharge electrodes are connected in common, and others of the pairs of sustain discharge electrodes are provided, individually and respectively, at respective display lines.