Automatic brightness control using a variable time constant filter
First Claim
Patent Images
1. A system for controlling brightness of an emissive display, comprising:
- (A) an ambient light sensor configured to output an ambient signal corresponding to a sensed ambient illumination level;
(B) a display configured to receive an actual display brightness signal and to adjust an actual display brightness level based on said actual display brightness signal; and
(C) a processor executing a stored program to;
(1) receive said ambient light signals;
(2) determine a desired display brightness level corresponding to said ambient light signal; and
(3) output said actual display brightness signal to said display, wherein said actual display brightness level is adjusted at a rate of change, and wherein said rate of change increases as a magnitude of the difference between said desired display brightness level and said actual display brightness level decreases.
14 Assignments
0 Petitions
Accused Products
Abstract
A method and apparatus is provided to control the brightness of an emissive display. Specifically, the brightness is incremented and decremented as the ambient environment becomes brighter and darker, respectively. A timing feature is also implemented to control the sensitivity of the system. Specifically, the time between adjustments of the display brightness is at least partially dependent on the magnitude of the difference between the desired brightness based on the ambient lighting environment and that of the actual display brightness.
78 Citations
31 Claims
-
1. A system for controlling brightness of an emissive display, comprising:
-
(A) an ambient light sensor configured to output an ambient signal corresponding to a sensed ambient illumination level;
(B) a display configured to receive an actual display brightness signal and to adjust an actual display brightness level based on said actual display brightness signal; and
(C) a processor executing a stored program to;
(1) receive said ambient light signals;
(2) determine a desired display brightness level corresponding to said ambient light signal; and
(3) output said actual display brightness signal to said display, wherein said actual display brightness level is adjusted at a rate of change, and wherein said rate of change increases as a magnitude of the difference between said desired display brightness level and said actual display brightness level decreases. - View Dependent Claims (2, 3, 4, 31)
-
-
5. A method for controlling brightness of an emissive instrument display, comprising:
-
(A) receiving a first signal indicating an actual display brightness level;
(B) determining a second signal that is related to a desired display brightness level, wherein the desired display brightness level is at least partially dependent upon an ambient illumination level;
(C) determining a brightness difference magnitude between said first and second signals; and
(D) adjusting said actual display brightness level after expiration of an update time interval, wherein said update time interval is at least partially dependent upon said brightness difference magnitude. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
subtracting T from T1 to determine a time difference variable; and
adjusting said actual brightness level when said time difference variable is greater than said update time interval.
-
-
12. The method as recited in claim 10, wherein said time constant is a first time constant if said actual display brightness level is greater than said desired display brightness level, and wherein said time constant is a second time constant if said actual display brightness level is less than said desired display brightness level, and wherein said first time constant is greater than said second time constant.
-
13. The method as recited in claim 5, further comprising manually adjusting said actual brightness level.
-
14. The method as recited in claim 5, wherein said desired brightness level is related to an ambient illumination condition.
-
15. The method as recited in claim 5, wherein actual brightness level is adjusted by one of increasing said actual brightness level and decreasing said actual brightness level, and wherein said actual brightness level is increased at a faster rate than it is decreased.
-
16. The method as recited in claim 5, wherein said actual brightness level is adjusted in small increments so as to be unnoticeable to the human eye.
-
17. The method as recited in claim 5, wherein said first signal is predetermined.
-
18. A method for controlling brightness of an emissive display, comprising:
-
(A) determining a first signal indicating an actual display brightness level at a first time T1;
(B) determining a second signal substantially related to a desired display brightness level at a second time T2;
(C) determining a difference magnitude between said first and second signals;
(D) determining a predetermined update time interval, wherein said update time interval is the product of said difference magnitude and a predetermined time constant;
(E) adjusting said actual display brightness level when the difference between T2 and T1 is greater than said update time interval. - View Dependent Claims (19, 20, 21)
-
-
22. A system for controlling brightness of an illuminated instrument panel, comprising:
-
(A) means for receiving a first signal generally related to an actual brightness level;
(B) means for receiving a second signal that is related to a desired brightness level, wherein the desired display brightness level is at least partially dependent upon an ambient illumination level;
(C) means for determining a brightness difference magnitude between said first and second signals; and
(D) means for adjusting said actual brightness level after expiration of a predetermined update time interval, wherein said update time interval is at least partially dependent upon said difference magnitude. - View Dependent Claims (23, 24, 25)
-
-
26. A system for controlling brightness of an emissive display, comprising:
-
(A) an ambient light sensor configured to output an ambient signal corresponding to a sensed ambient illumination level;
(B) a display configured to receive an actual display brightness signal and to adjust an actual display brightness level based on said actual display brightness signal; and
(C) a processor executing a stored program to;
(1) receive said ambient light signals;
(2) determine a desired display brightness level corresponding to said ambient light signal; and
(3) output said actual display brightness signal to said display, wherein said actual display brightness level is adjusted at a rate of change, and wherein said rate of change decreases as a magnitude of the difference between said desired display brightness level and said actual display brightness level increases. - View Dependent Claims (27, 28, 29, 30)
-
Specification