Liquid-crystal display apparatus and electronic device

• US 20060256257A1
• Filed: 05/05/2006
• Published: 11/16/2006
• Est. Priority Date: 05/11/2005
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Saiki, Kunihito, Nakano, Minoru
• Granted Patent: US 7,333,165 B2
• Time in Patent Office: Days
• US Class Current: 349/80
• CPC Class Codes: G02F 1/133621 providing coloured light G02F1/133617, G02F1/133533 take precedence
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• CPC Class Codes: G09G 2320/0666 for control of colour parameters, e.g. colour temperature
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 2360/144 the light being ambient light
• CPC Class Codes: G09G 3/3413 Details of control of colour illumination sources
• CPC Class Codes: G09G 3/3611 Control of matrices with row and column drivers

Abstract

A liquid-crystal display apparatus includes a liquid-crystal panel (25) having a color filter (26), a W light-emitting diode (22w) for irradiating white light to the liquid-crystal panel (25), RGB light-emitting diodes (22r, 22g, 22b) for irradiating lights of more than two colors containing white to the liquid-crystal panel (25), a luminance sensor (44) for detecting ambient illuminance of the liquid-crystal panel (25) to output a detected signal and a control unit (41) for switching the W light-emitting diode (22w) and the RGB light-emitting diodes (22r, 22g, 22b) based on the detected signal from the luminance sensor (44). In a related-art liquid-crystal display apparatus, since lights of red (R), green (G) and blue (B) are emitted with a time lag and superimposed upon each other so that a clear color may not be obtained in each pixel, thus resulting in insufficient color reproducing capability. According to the present invention, these defects encountered with the related art can be obviated.

Claims

1. A liquid-crystal display apparatus comprising:

a liquid-crystal panel having a color filter;

a first light source for irradiating first white light to said liquid-crystal panel;

a second light source for irradiating, second white light different from the first white light to said liquid-crystal panel;

illuminance detecting means for, detecting ambient illuminance of said liquid-crystal panel to output a detected signal; and

light source control means for switching said first and second light sources based on the detected signal from said illuminance detecting means.

2. A liquid-crystal display apparatus according to claim 1, wherein said second light source is composed of a combination of more than two light-emitting bodies which emit lights of different colors, the combination being capable of generating white light by combining lights radiated from all light-emitting bodies.

3. A liquid-crystal display apparatus according to claim 1, wherein said light source control means compares the illuminance detected value detected based on the detected signal from said illuminance detecting means with a predetermined illuminance reference value, said light source control means energizes said first light source if it is determined based on the compared result that said illuminance detected value is larger than said illuminance reference value and said light source control means energizes said second light source if it is determined based on the compared result that the illuminance detected value is smaller than said illuminance reference value.

4. A liquid-crystal display apparatus according to claim 1, wherein said illuminance detecting means includes at least one of a luminance sensor and a white balance sensor.

5. An electronic device including a liquid-crystal display device comprising a liquid-crystal panel having a color filter, a first light source for irradiating first white light to the liquid-crystal panel and a second light source for irradiating second white light different from said first white light to said liquid-crystal panel and a control apparatus for displaying color image by controlling the state in which light is passed through said liquid-crystal panel or light is reflected on said liquid-crystal panel, said liquid-crystal display apparatus comprising:

illuminance detecting means for detecting ambient illuminance of said liquid-crystal panel to output a detected signal; and

light source control means for switching said first and second light sources based on the detected signal from said illuminance detecting means.