Browse Prior Art Database

Backlight Compensation for Ambient Lighting

IP.com Disclosure Number: IPCOM000113582D
Original Publication Date: 1994-Sep-01
Included in the Prior Art Database: 2005-Mar-27
Document File: 2 page(s) / 67K

Publishing Venue

IBM

Related People

Gladstein, L: AUTHOR [+2]

Abstract

Disclosed is the automatic adjustment of a level at which backlighting is provided for the display screen of a portable tablet computer system, in response to changes in ambient lighting, as measured by a photodetector. This automatic adjustment of backlighting generally extends the time allowed between charging cycles of the battery of the computer, while providing the user with an optimal setting of brightness and contrast ratio for the display.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Backlight Compensation for Ambient Lighting

      Disclosed is the automatic adjustment of a level at which
backlighting is provided for the display screen of a portable tablet
computer system, in response to changes in ambient lighting, as
measured by a photodetector.  This automatic adjustment of
backlighting generally extends the time allowed between charging
cycles of the battery of the computer, while providing the user with
an optimal setting of brightness and contrast ratio for the display.

      The Figure is a schematic diagram of a method used to provide
this feature.  In block 1, a manual input is provided by the user,
who may set the level of backlighting at a different value than the
default level otherwise chosen by the system.  In block 2, a signal
level representative of ambient lighting is provided by the
photodetector, which is preferably mounted in the tablet computer in
such a way that it measures the level of light falling on the surface
of the display.  In block 3, a decision on whether to proceed with
the adjustment process is based on whether the display is turned on.
If the display is off, the settings are not changed.  Thus, if the
tablet computer is being transported from one location to another
while not being used, no change is made to the brightness level until
power is restored to the display.

      The user is also given an opportunity, in block 4, to provide
an input to the "preferences" function of the operating system used
in the tablet computer.  Within this function, a default setti...