Display device
First Claim
1. A display device which comprises:
- a display screen;
an ambient light sensor positioned adjacent said display screen so as to confront an occupant in front of said display screen;
a screen luminance calculating unit for calculating an adjustable range of screen luminance to be adjusted on the basis of an output signal from said ambient light sensor;
a luminance level setting unit for inputting a desired luminance level;
a luminance determining unit for determining a proper screen luminance based on an output signal from said screen luminance calculating unit and an output signal from said luminance level setting unit;
a screen luminance control unit operable in response to an output signal from said luminance determining unit to adjust the screen luminance so that a visibility level, which is a ratio of a contrast of an object on said display screen against a screen background to a minimum threshold contrast at which said object is discernible to the occupant, is within a predetermined range, the contrast of the object being determined based on an equivalent screen luminance which represents an amount of ambient light reflected from the object on the screen and subsequently scattered within eyeballs of the occupant;
wherein said ambient light sensor includes an illuminance meter and detects an ambient illuminance I; and
wherein said luminance determining unit calculates the adjustable range of screen luminance L so as to satisfy the following relationship;
space="preserve" listing-type="equation">18·
I.sup.0.139 ≦
L≦
53·
I.sup.0.113.
1 Assignment
0 Petitions
Accused Products
Abstract
A display device includes an ambient light sensor positioned adjacent a display screen so as to confront an occupant in front of the display device, and a luminance level setting unit for inputting a desired luminance level. An output from the ambient light sensor is fed to a screen luminance calculating unit for calculating the adjustable range of screen luminance to be adjusted on the basis of an output signal from the ambient light sensor. A luminance determining unit determines a proper screen luminance based on an output signal from the screen luminance calculating unit and an output signal from the luminance level setting unit. A screen luminance control unit operates in response to an output signal from the luminance determining unit to adjust the screen luminance to the proper screen luminance.
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Citations
6 Claims
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1. A display device which comprises:
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a display screen; an ambient light sensor positioned adjacent said display screen so as to confront an occupant in front of said display screen; a screen luminance calculating unit for calculating an adjustable range of screen luminance to be adjusted on the basis of an output signal from said ambient light sensor; a luminance level setting unit for inputting a desired luminance level; a luminance determining unit for determining a proper screen luminance based on an output signal from said screen luminance calculating unit and an output signal from said luminance level setting unit; a screen luminance control unit operable in response to an output signal from said luminance determining unit to adjust the screen luminance so that a visibility level, which is a ratio of a contrast of an object on said display screen against a screen background to a minimum threshold contrast at which said object is discernible to the occupant, is within a predetermined range, the contrast of the object being determined based on an equivalent screen luminance which represents an amount of ambient light reflected from the object on the screen and subsequently scattered within eyeballs of the occupant; wherein said ambient light sensor includes an illuminance meter and detects an ambient illuminance I; and wherein said luminance determining unit calculates the adjustable range of screen luminance L so as to satisfy the following relationship;
space="preserve" listing-type="equation">18·
I.sup.0.139 ≦
L≦
53·
I.sup.0.113. - View Dependent Claims (2, 3, 4, 5, 6)
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Specification