Color liquid crystal display device

• US 20020063670A1
• Filed: 11/28/2001
• Published: 05/30/2002
• Est. Priority Date: 11/30/2000
• Status: Active Grant

• Current Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Original Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Inventors: Yoshinaga, Hideki, Miura, Seishi, Mori, Hideo
• Granted Patent: US 6,961,038 B2
• Time in Patent Office: Days
• US Class Current: 345/87
• CPC Class Codes: G09G 2310/0235 Field-sequential colour display
• CPC Class Codes: G09G 2320/0242 Compensation of deficiencies in the appearance of colours
• CPC Class Codes: G09G 2320/0261 in the context of movement of objects on the screen or movement of the observer relative to the screen
• CPC Class Codes: G09G 2320/0276 for the purpose of adaptation to the characteristics of a display device, i.e. gamma correction
• CPC Class Codes: G09G 2320/103 Detection of image changes, e.g. determination of an index representative of the image change
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 2340/06 Colour space transformation
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• 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

The color liquid crystal display device of the present invention has at least a liquid crystal display part, and light sources for irradiating the liquid crystal display part with lights of three primary colors, respectively, and performs display of one frame by respective fields of three primary colors and a white field displayed with a mixture of the three primary colors in the liquid crystal display part, wherein the device further comprises: means for comparing brightness levels of inputted three primary color signals for one frame with each other to define a maximum value thereof as a brightness level of a white signal for one frame; means for setting a proportion of the brightness level of the white signal to be displayed in the white field; and a light source driving part for driving the light sources of the three primary colors so that the white field emits light depending on the brightness level of the white signal and the proportion.

Claims

1. A color liquid crystal display device comprising a liquid crystal display part, and light sources for irradiating the liquid crystal display part with lights of three primary colors, respectively, the device performing display of one frame by respective fields of three primary colors and a white field displayed with a mixture of the three primary colors in the liquid crystal display part,

wherein the device further comprises:

means for comparing brightness levels of inputted three primary color signals for one frame with each other to define a maximum value thereof as a brightness level of a white signal for one frame;

means for setting a proportion of the brightness level of the white signal to be displayed in the white field; and

a light source driving part for driving the light sources of the three primary colors so that the white field emits light depending on the brightness level of the white signal and the proportion.

3. The color liquid crystal display device according to claim 1, wherein the proportion is automatically set depending on changes of displayed image information.

4. The color liquid crystal display device according to claim 1, wherein the proportion is set by a manual switch.

5. The color liquid crystal display device according to claim 1, wherein in a frame with the proportion equal to 0%, one frame is divided into three fields to perform display only by three-color fields.

2. A color liquid crystal display device comprising a liquid crystal display part, and light sources for irradiating the liquid crystal display part with lights of the three primary colors, respectively, the device performing display of one frame by respective fields of the three primary colors and a white field displayed with a mixture of the three primary colors in the liquid crystal display part,

wherein the device further comprises a light source driving part for driving the light sources of the three primary colors, and

wherein when brightness levels of inputted three primary color signals for one frame are compared with each other to define a maximum value thereof as a brightness level of a white signal for one frame, the light source driving part is driven depending on the brightness level of the white signal, and a proportion of the brightness level of the white signal to be displayed with the white field.