Display apparatus

• US 6,184,875 B1
• Filed: 11/12/1998
• Issued: 02/06/2001
• Est. Priority Date: 11/14/1997
• Status: Expired due to Term

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Matsuura, Makoto
• Primary Examiner(s): Liang, Regina
• Application Number:
  US09/190,096
• Time in Patent Office: 817 Days
• Field of Search: 345/87, 345/211, 345/212, 345/213, 345/102, 348/730
• US Class Current: 345/211
• CPC Class Codes: G06F 1/3203 Power management, i.e. event-based initiation of a power-saving mode
• CPC Class Codes: G06F 1/3265 Power saving in display device
• CPC Class Codes: G09G 1/005 Power supply circuits
• CPC Class Codes: G09G 2330/022 in absence of operation, e.g. no data being entered during a predetermined time
• CPC Class Codes: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management
• CPC Class Codes: Y02D 30/50 in wire-line communication networks, e.g. low power modes or reduced link rate

Abstract

A display apparatus includes a CPU, an image display device, a light source for irradiating the image display device, a circuit for turning on/off the light source, a means for determining the resolution of the input image signal, a first switching means for turning on/off the power supply to the circuit components except the light source turning on/off circuit and a second switching means for turning on/off the power supply to the light source turning on/off circuit. In a first power-saving mode, the circuits may be opened by means of the first switching means after an appropriately selectable first predetermined period of time and may be opened by means of the second switching means after an appropriately selectable second predetermined period of time. A second power-saving mode is also provided for opening the first and second switching means by a combination of the polarity of the input horizontal synchronizing signal and that of the input vertical synchronizing signal. The first power-saving mode and the second power-saving mode may be used selectively.

Claims

1. A display apparatus comprising a CPU, an image display device, a light source for irradiating the image display device, a circuit for turning on/off the light source, a means for determining the resolution of the input image signal, a first switching means for turning on/off the power supply to the circuit components except the light source turning on/off circuit and a second switching means for turning on/off the power supply to the light source turning on/off circuit and adapted to operate in a first power-saving mode for opening the circuits by means of said first switching means after an appropriately selectable first predetermined period of time and also open the circuits by means of said second switching means after an appropriately selectable second predetermined period of time or in a second power-saving mode for opening said first and second switching means by a combination of the polarity of the input horizontal synchronizing signal and that of the input vertical synchronizing signal, said first power-saving mode and said second power-saving mode being able to be selectively used.

2. A display apparatus according to claim 1, wherein the first power-saving mode is used when the absence of image signal is detected and when the input image signal has a frequency out of the frequency range with which the apparatus is adapted to display images.

3. A display apparatus according to claim 1, wherein said first power-saving mode or said second power-saving mode can be selectively used for a plurality of input image signals with different resolutions.

4. A display apparatus according to claim 1, wherein it comprises a plurality of image signal input terminals and said first power-saving mode or said second power-saving mode can be selectively used for each of the input terminals.

5. A display apparatus according to any of claims 1 through 4, wherein the resolution of said input image signal is determined by counting horizontal synchronizing signals within a period of a vertical synchronizing signal of said input image signal.

6. A display apparatus according to any of claims 1 through 4, wherein the light source lamp driven by said light source lamp turning on/off circuit is used as light source of the liquid crystal panel.