# US 8,570,317 B2 · Image display device

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- Number: US 8,570,317 B2
- Document ID: US8570317B2
- Status: Granted
- Kind: B2
- Application number: 13/029,651
- Filed: 2011-02-17
- Published: 2011-09-15
- Granted: 2013-10-29
- Earliest claimed: 2010-03-15
- Assignees: Mitsubishi Electric Corporation
- Applicants: Makoto Kuriaki
- Inventors: Makoto Kuriaki
- Web page: https://patentgrep.com/patent/US8570317B2

## CPC

- G09G 3/02: by tracing or scanning a light beam on a screen
- G09G 2320/041: Temperature compensation
- G09G 2330/045: Protection against panel overheating
- 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)

## Abstract

There is provided an image display device including: a laser element that generates light for projecting and displaying an image on a display screen; a Peltier device unit that cools the laser element; a detecting unit that detects a temperature of the laser element; and a control unit that controls driving of the Peltier device unit so that a temperature detected by the detecting unit becomes a target temperature, wherein the control unit controls driving of the laser element to reduce a light output of the laser element when a driving rate of the Peltier device unit exceeds a threshold that indicates that the driving rate approaches a maximum value.

## Claims

### Claim 1

An image display device comprising:
a laser element that generates light for projecting and displaying an image on a display screen;
a Peltier device unit that cools the laser element;
a detecting unit that detects a temperature of the laser element; and
a control unit that controls driving of the Peltier device unit so that a temperature detected by the detecting unit becomes a target temperature, wherein
the control unit controls driving of the laser element to reduce a light output of the laser element when a driving rate of the Peltier device unit exceeds a threshold that indicates that the driving rate approaches a maximum value; and
wherein the control unit controls the driving of the laser element to increase a light output of the laser element when a duration of a state, in which a driving rate of the Peltier device unit becomes lower than the threshold, is longer than a second threshold.

### Claim 2 (depends on 1)

The image display device according to claim 1, further comprising:
a second detecting unit that detects a light output of the laser element; and
a projection display unit that receives light output from the laser element to project and display an image on the display screen, wherein
the control unit controls the projection display unit to project and display a warning on the display screen when a light output detected by the second detecting unit becomes lower than a third threshold.