US 2009/0153464 A1 · DISPLAY UNIT AND BACKLIGHT UNIT

Abstract

The screen is exempt from variation in brightness due to uneven temperature distribution. The color liquid crystal display unit has a color display panel of transmissive type and a backlight unit placed behind the color display panel. The backlight unit has a plurality of LEDs connected in series, the drive unit to drive the LEDs in correspondence with the LEDs, and the temperature sensor to detect the temperature of LEDs. The groups of LEDs are arranged in regions where the display unit has the same temperature. The drive unit controls current to be supplied to LEDs in response to temperature detected by the temperature sensor so that the LEDs retain the constant brightness even when the LEDs fluctuate in temperature.

Claims10

Dependent claims

1-9. (canceled)

A display unit comprising:

a non-luminous screen of transmissive-type, lighting units, placed behind the screen, each lighting unit comprising:
a light emitting diode, and
a temperature detecting unit to detect the temperature of the lighting unit, and
a drive unit to control current supplied to the light emitting diode according to the temperature of the lighting unit, so that each lighting unit keeps a uniform brightness even though each lighting unit changes in temperature, to adjust current to be supplied to the light emitting diode by means of pulse width modulation, so as to keep at least the brightness of light emitted from each lighting unit uniform, to control the peak value of the current to be supplied to the light emitting diode, so that the resolution of pulse width is the same, and to adjust the peak value of current to be supplied to the light emitting diode in response to the detected temperature.

1 more element

Dependencies are inferred from the claim text.

Facts

Application

12/370,578Filed 12 Feb 2009

Priority

JP JP 2004-20514412 Jul 2004

Published

18 Jun 2009

Term ends

Not estimatedThe source records don’t support an estimate.

Classification10 codes

G09G 3/342
Control of illumination source: using several illumination sources separately controlled corresponding to different display panel areas, e.g.…
G02F 1/133603
Direct backlight: with LEDs
G09G 3/3413
Control of illumination source: details of control of colour illumination sources
G09G 2320/0233
Improving the quality of display appearance: improving the luminance or brightness uniformity across the screen

Display unit and backlight unit

Life of this patent

Display unit and backlight unit

Life of this patent

Abstract

Claims10