# US 2009/0262104 A1 · Image display apparatus and voltage control method

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- Number: US 2009/0262104 A1
- Document ID: US20090262104A1
- Status: Published application
- Kind: A1
- Application number: 12/420,411
- Filed: 2009-04-08
- Published: 2009-10-22
- Earliest claimed: 2008-04-16
- Assignees: Seiko Epson Corporation
- Inventors: Tomio IKEGAMI
- Web page: https://patentgrep.com/patent/US20090262104A1

## CPC

- G09G 3/02: by tracing or scanning a light beam on a screen
- H04N 9/3129: {scanning a light beam on the display screen (scanning a light beam on a screen in displays other than projection devices G09G3/02; scanning systems in general G02B26/10; projectors using laser light sources in general H04N9/3161)}
- H04N 9/3155: {for controlling the light source (light source control per se H05B35/00 – H05B47/00; control of an illumination source for displays in general G09G3/3406)}
- H04N 9/3164: {using multiple light sources}
- G09G 2330/021: Power management, e.g. power saving
- G09G 2360/16: Calculation or use of calculated indices related to luminance levels in display data
- G09G 2360/18: Use of a frame buffer in a display terminal, inclusive of the display panel
- G09G: ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION (arrangements for transferring data between digital computers and displays G06F3/14; static indicating arrangements comprising an association of a number of separate sources or light control cells G09F9/00; static indicating arrangements comprising integral associations of a number of light sources H01J, H01K, H10H, H05B33/12; scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission, details thereof H04N1/00)
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

An image display apparatus includes a light source, a scanner that scans an output beam emitted from the light source to forms an image on a projection surface, a light source driver that control intensity of the output beam emitted from the light source by controlling a drive current for driving the light source based on input image data, a light source drive power supply that supplies power to the light source driver, and a voltage controller that controls an output voltage from the light source drive power supply based on the input image data.

## Claims

### Claim 1

An image display apparatus comprising:
a light source;
a scanner that scans an output beam emitted from the light source to forms an image on a projection surface;
a light source driver that control intensity of the output beam emitted from the light source by controlling a drive current for driving the light source based on input image data;
a light source drive power supply that supplies power to the light source driver; and
a voltage controller that controls an output voltage from the light source drive power supply based on the input image data.

### Claim 2 (depends on 1)

The image display apparatus according to claim 1,
wherein when the input image data are divided into predetermined data units, the voltage controller controls the output voltage to have a fixed voltage magnitude based on the image data that belong to each of the predetermined data units.

### Claim 3 (depends on 2)

The image display apparatus according to claim 2,
wherein the fixed voltage magnitude is determined based on the maximum intensity among intensities of the output beam emitted from the light source and corresponding to the image data that belong to the predetermined data unit.

### Claim 4

A voltage control method used in an image display apparatus including a light source, a light source driver that controls intensity of an output beam emitted from the light source based on input image data, a light source drive power supply that supplies power to the light source driver, and a scanner that scans the output beam emitted from the light source, for controlling an output voltage from the light source drive power supply, the method comprising:
(a) when the input image data are divided into predetermined data units, detecting the maximum intensity among the intensities of the output beam emitted from the light source and corresponding to the image data that belong to each of the predetermined data units;
(b) calculating a value specifying the output voltage from the light source drive power supply based on the maximum intensity detected in (a); and
(c) controlling the output voltage from the light source drive power supply to have the output voltage specifying value calculated in (b).