Display brightness control method and apparatus for conserving battery power

• US 6,731,274 B2
• Filed: 05/15/2003
• Issued: 05/04/2004
• Est. Priority Date: 10/28/1999
• Status: Expired due to Term

• Current Assignee: Gateway Incorporated (Acer, Inc.)
• Original Assignee: Gateway Incorporated (Acer, Inc.)
• Inventors: Powell, John P.
• Primary Examiner(s): Hjerpe, Richard
• Assistant Examiner(s): Laneau, Ronald
• Application Number:
  US10/439,062
• Publication Number:
  US 20030193472A1
• Time in Patent Office: 355 Days
• Field of Search: 345/204, 345/211, 345/87, 345/102, 345/147, 345/156
• US Class Current: 345/204
• CPC Class Codes: G06F 1/263 Arrangements for using multiple switchable power supplies, e.g. battery and AC G06F1/30 takes precedence
• 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 2320/0626 for control of overall brightness
• CPC Class Codes: G09G 2320/08 Arrangements within a display terminal for setting, manually or automatically, display parameters of the display terminal
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 3/2092 Details of a display terminals using a flat panel, the details relating to the control arrangement of the display terminal and to the interfaces thereto suitable for both CRT and flat panel G09G5/003; specific for a CRT G09G1/165
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336
• CPC Class Codes: G09G 5/006 Details of the interface to the display terminal specific for a display terminal using a CRT G09G1/167; using a flat panel G09G3/2096; circuits for interfacing with colour displays G09G5/04
• CPC Class Codes: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management

Abstract

A method and apparatus for reducing display brightness on a portable computer when a user switches from an AC adapter to a battery power source provide battery power conservation. The reduction in display brightness is performed gradually so that a sudden brightness drop is not detected by the user. The display brightness reduction is preferably performed sufficiently gradually so that the reduction in brightness is virtually unnoticeable to the human eye.

Claims

1. A method for conserving battery power in a portable computer, said computer being of the type operable on power supplied by a battery power source and an external power source, comprising the steps of:

detecting a change from the external power source to the battery power source;

reducing display brightness gradually from a user selected brightness level to a target brightness level if the target brightness level is less than the user selected brightness level; and

leaving the display brightness level unchanged if the target brightness level is not less than the user selected display brightness level,

wherein the step of reducing the display brightness gradually occurs through use of a rate limiting function so as to be substantially undetectable to a user when battery operation is detected.

2. The method according to claim 1, wherein said computer is further of the type having a hard disk drive and wherein said method further comprises the step of spinning down said hard disk drive after a prespecified period of nonuse.

3. The method according to claim 1, wherein said method further comprises the step of reducing the display brightness after a prespecified period of nonuse.

4. The method according to claim 1, wherein said method further comprises the step of powering off the display after a prespecified period of nonuse.

5. The method according to claim 1, wherein said method further comprises the step of powering off the computer after a prespecified period of nonuse.

6. The method according to claim 1, wherein said method further comprises the step of reducing a processor operating speed when battery operation is selected.

7. The method according to claim 1, wherein said method further comprises the step of putting the computer into a low power sleep mode after a prespecified period of nonuse.

8. The method according to claim 1, wherein said method further comprises the step of increasing display brightness to a user selected brightness level when external power operation is selected.

9. An apparatus for conserving battery power in a portable computer, said computer being of the type operable on power supplied by a battery power source and an external power source, said apparatus comprising:

means for detecting a change from the external power source to the battery power source; and

means for reducing display brightness gradually from a user selected brightness level to a target brightness level if the target brightness level is less than the user selected brightness level; and

means for leaving the display brightness level unchanged if the target brightness level is not less than the user selected display brightness level,

wherein the means for reducing the display brightness gradually occurs through use of a rate limiting function so as to be substantially undetectable to a user when battery operation is detected.

10. The apparatus according to claim 9, said computer is further of the type having a hard disk drive and further comprising means for spinning down said hard disk drive after a prespecified period of nonuse.

11. The apparatus according to claim 9, comprising means for further reducing the display brightness after a prespecified period of nonuse.

12. The apparatus according to claim 9, comprising means for powering off the display after a pre specified period of nonuse.

13. The apparatus according to claim 9, comprising means for powering off the computer after a prespecified period of nonuse.

14. The apparatus according to claim 9, comprising means for reducing a processor operating speed when battery operation is selected.

15. The apparatus according to claim 9, comprising means for putting the computer into a low power sleep mode after a prespecified period of nonuse.

16. The apparatus according to claim 9, further comprising means for increasing display brightness to a user selected brightness level when external power operation is selected.