Light illumination apparatus and liquid crystal display apparatus using the same

• US 7,463,235 B2
• Filed: 04/21/2003
• Issued: 12/09/2008
• Est. Priority Date: 08/03/2000
• Status: Expired due to Fees

• Current Assignee: Panasonic Liquid Crystal Display Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Hitachi, Ltd.
• Inventors: Yamamoto, Tsunenori, Aono, Yoshinori, Hiyama, Ikuo, Tsumura, Makoto
• Primary Examiner(s): Awad; Amr
• Assistant Examiner(s): Sherman; Stephen G
• Application Number:
  US10/419,578
• Publication Number:
  US 20030201969A1
• Time in Patent Office: 2,059 Days
• Field of Search: 345/102, 345/87, 345/76, 345/82, 345/55, 345/204, 345/214, 345694-696, 349/10, 349/48, 349/83, 349/61, 3151691-1694
• US Class Current: 345/102
• CPC Class Codes: G02B 6/0033 Means for improving the coupling-out of light from the light guide
• CPC Class Codes: G02B 6/0055 Reflecting element, sheet or layer
• CPC Class Codes: G02B 6/0056 for producing polarisation effects, e.g. by a surface with polarizing properties or by an additional polarizing elements
• CPC Class Codes: G02F 1/011 in optical waveguides, not otherwise provided for in this subclass
• CPC Class Codes: G02F 1/1334 based on polymer dispersed liquid crystals, e.g. microencapsulated liquid crystals
• CPC Class Codes: G02F 1/13756 the liquid crystal selectively assuming a light-scattering state G02F1/1334, G02F1/13718 take precedence
• CPC Class Codes: G09G 2300/0434 Flat panel display in which a field is applied parallel to the display plane
• CPC Class Codes: G09G 2310/024 Scrolling of light from the illumination source over the display in combination with the scanning of the display screen
• CPC Class Codes: G09G 2310/08 Details of timing specific for flat panels, other than clock recovery
• CPC Class Codes: G09G 2320/0238 Improving the black level
• 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 2320/0606 Manual adjustment
• CPC Class Codes: G09G 2320/066 for control of contrast
• CPC Class Codes: G09G 3/342 using several illumination sources separately controlled corresponding to different display panel areas, e.g. along one dimension such as lines

Abstract

A light illumination apparatus and a liquid crystal display using the apparatus, comprising a light source on a lateral side and a reflector on the backside of a light-pipe, further comprising an air layer between the light-pipe and the reflector, further comprising a light scattering control layer disposed at a portion of the light-pipe and having directivity in a direction substantially normal to the light emission plane, where total internal reflection of the incident light from the light source at an interface of the light-pipe is achieved, and a means for moving the predetermined region, wherein the time average amount of emitted light is substantially equal in each of all light emission regions, and there is time when the light emissive region substantially does not emit light.

Claims

1. A blanking method of a display comprising the steps of:

selecting predetermined light emission regions from light emission possible regions, and

moving said light emission regions for each period, wherein

the area of said light emission regions is constant in each period, and

a location of said area of said light emission regions is changed every period,

wherein the light emission regions emit light generated from a common light source, and

wherein the periods form a frame period, and the ratio of selected light emission regions over the light emission possible regions is greater than the ratio of the period over the frame period, and wherein

the light emission region is a region where the common light source is on, and that region allows light from the common light source to emit.

2. A blanking method as set forth in claim 1, wherein the intensity of light emitted from said light emission regions is controlled when the location of said area of said light emission regions is changed every period.

3. A blanking method as set forth in claim 2, wherein the value obtained upon dividing the intensity of light emitted from said light emission regions by the intensity of light emitted in the case where all of said light emission possible regions are made to be light emission regions is equal to the value obtained upon dividing the area of said light emission possible regions by the area of said light emission regions.

4. A blanking method as set forth in claim 2, wherein the value obtained upon dividing the intensity of light emitted from said light emission regions by the intensity of light emitted in the case where all of said light emission possible regions are made to be light emission regions is not less than one.

5. A blanking method as set forth in claim 1, wherein said light emission regions are moved so that the period of time for which light is emitted in an arbitrary region of said light emission possible regions is roughly the same in each period.

6. A blanking method of a display comprising the steps of:

selecting predetermined light emission regions from light emission possible regions in a light illumination apparatus in accordance with driving scan of a liquid crystal display device, and

moving said light emission regions to input light to said liquid crystal display device, wherein

where said liquid crystal display device displays a picture for I/k (where k is an integer of not less than

     2) of each period,

said light illumination apparatus ensures that the intensity of light emitted from said light emission regions is not less than k times the intensity of light emitted in the case where all of said light emission possible regions are made to be light emission regions,

wherein the light emission regions emit light generated from a common light source, and

wherein the periods form a frame period, and the ratio of selected light emission regions over the light emission possible regions is greater than the ratio of the period over the frame period, and wherein

the light emission region is a region where the common light source is on, and that region allows light from the common light source to emit.

7. A blanking method of a display comprising the steps of:

selecting predetermined light emission regions from light emission possible regions, and

moving said light emission regions for each period, wherein

the area of said light emission regions is constant in each period, and a location of said area of said light emission regions is changed every period,

wherein the light emission regions emit light generated from a common light source, and

wherein the periods form a frame period, and the selected light emission regions overlap between one period and the next period, and wherein

the light emission region is a region where the common light source is on, and that region allows light from the common light source to emit.

8. A blanking method as set forth in claim 7, wherein the intensity of light emitted from said light emission regions is controlled when the location of said area of said light emission regions is changed every period.

9. A blanking method as set forth in claim 8, wherein the value obtained upon dividing the intensity of light emitted from said light emission regions by the intensity of light emitted in the case where all of said light emission possible regions are made to be light emission regions is equal to the value obtained upon dividing the area of said light emission possible regions by the area of said light emission regions.

10. A blanking method as set forth in claim 8, wherein the value obtained upon dividing the intensity of light emitted from said light emission regions by the intensity of light emitted in the case where all of said light emission possible regions area made to be light emission regions is not less than one.

11. A blanking method as set forth in claim 7, wherein said light emission regions are moved so that the period of time for which light is emitted in an arbitrary region of said light emission possible regions is roughly the same in each period.