Display driver
First Claim
Patent Images
1. A display driver comprising:
- a first backlight control unit including a circuit for switching brightness of a display image based on a display data value at a predetermined position of a histogram of inputted display data and a circuit for switching backlight luminance based on the display data value, an object of detection of the histogram being a data range from a brightest level to an N-th level of gray-scale (N is a positive integer and is not
0) of the display data;
a second backlight control unit including a circuit for backlight luminance control different from the first backlight control unit; and
a generating unit setting a backlight control signal value consisting of a product of a luminance rate of X % and a luminance rate of Y % as a luminance rate of a backlight control signal for controlling a backlight with respect to maximum backlight luminance where a luminance rate of the backlight control signal obtained by a processing of the first backlight control unit with respect to the maximum backlight luminance is defined as X % (0<
X<
100) and a luminance rate of the backlight control signal obtained by a processing of the second backlight control unit with respect to the maximum backlight luminance is defined as Y % (0<
Y<
100),wherein the circuit for backlight luminance control of the second backlight control unit senses external-light luminance with an optical sensor and adjusts the backlight luminance, andwherein the luminance rate of Y % is defined based on the external-light luminance.
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Abstract
In a display driver, a first backlight control unit using a histogram and a second backlight control unit using an optical sensor can be used in combination. The display driver includes a PWM generating unit setting a control signal value consisting of a product of a luminance rate of X % and a luminance rate of Y % as a luminance rate of a control signal for controlling a backlight with respect to maximum backlight luminance when a luminance rate of a control signal obtained by first backlight control with respect to the maximum backlight luminance is X % and a luminance rate of a control signal obtained by second backlight control with respect to the maximum backlight luminance is Y %.
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Citations
14 Claims
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1. A display driver comprising:
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a first backlight control unit including a circuit for switching brightness of a display image based on a display data value at a predetermined position of a histogram of inputted display data and a circuit for switching backlight luminance based on the display data value, an object of detection of the histogram being a data range from a brightest level to an N-th level of gray-scale (N is a positive integer and is not
0) of the display data;a second backlight control unit including a circuit for backlight luminance control different from the first backlight control unit; and a generating unit setting a backlight control signal value consisting of a product of a luminance rate of X % and a luminance rate of Y % as a luminance rate of a backlight control signal for controlling a backlight with respect to maximum backlight luminance where a luminance rate of the backlight control signal obtained by a processing of the first backlight control unit with respect to the maximum backlight luminance is defined as X % (0<
X<
100) and a luminance rate of the backlight control signal obtained by a processing of the second backlight control unit with respect to the maximum backlight luminance is defined as Y % (0<
Y<
100),wherein the circuit for backlight luminance control of the second backlight control unit senses external-light luminance with an optical sensor and adjusts the backlight luminance, and wherein the luminance rate of Y % is defined based on the external-light luminance. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A display driver comprising:
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a first backlight control unit including a circuit for switching brightness of a display image based on a display data value at a predetermined position of a histogram of inputted display data and a circuit for switching backlight luminance based on the display data value, an object of detection of the histogram being a data range from a brightest level to an N-th level of gray-scale (N is a positive integer and is not
0) of the display data;a second backlight control unit including a circuit for backlight luminance control different from the first backlight control unit; and a generating unit, when a luminance rate of a backlight control signal obtained by a processing of the second backlight control with respect to the backlight maximum luminance is Y % and the luminance rate of Y % is smaller than a luminance rate of Q % with respect to the backlight maximum luminance set as a threshold, the generating unit stopping a processing of the first backlight control unit and setting a backlight control signal value of a luminance rate of Y % as a luminance rate of a backlight control signal for controlling a backlight with respect to backlight maximum luminance, wherein the circuit for backlight luminance control of the second backlight control unit senses external-light luminance with an optical sensor and adjusts the backlight luminance, and wherein the luminance rate of Y % is defined based on the external-light luminance. - View Dependent Claims (8, 9, 10, 11, 12)
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13. A display driver for use with an optical sensor for sensing external-light luminance and a display panel with a backlight the display driver comprising:
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an interface coupled to receive display data; a memory which stores the display data; a circuit which provides to the display panel gray scale voltages based on the display data received from the memory; a first backlight control unit for backlight luminance control based on the display data received from the memory, the first backlight control unit providing a first backlight control signal representing a first luminance rate (X %) of the backlight; a second backlight control unit for backlight luminance control based on an output signal from the optical sensor, the second backlight control unit providing a second backlight control signal representing a second luminance rate (Y %) of the backlight; and a PWM (Pulse Width Modulation) signal generation circuit which is coupled to receive the first backlight control signal and the second backlight control signal and which provides to the backlight a PWM control signal based on the first backlight control signal and the second backlight control signal, and wherein the luminance rate of Y % is defined based on the external-light luminance. - View Dependent Claims (14)
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Specification