Illuminating apparatus and display apparatus

• US 8,264,450 B2
• Filed: 04/09/2009
• Issued: 09/11/2012
• Est. Priority Date: 04/15/2008
• Status: Active Grant

• Current Assignee: Saturn Licensing LLC (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Furukawa, Norimasa, Shimizu, Jun
• Primary Examiner(s): Dharia, Prabodh M
• Application Number:
  US12/384,876
• Publication Number:
  US 20090295707A1
• Time in Patent Office: 1,251 Days
• Field of Search: 345/89, 345/102, 349/48, 349/59, 349/61, 349/85, 349/89, 349 96-105, 349 69- 77, 349114-123, 353/8, 353/20
• US Class Current: 345/102
• CPC Class Codes: G02F 1/133601 for spatial active dimming
• CPC Class Codes: G02F 1/133602 Direct backlight
• CPC Class Codes: G09G 2300/023 Display panel composed of stacked panels
• CPC Class Codes: G09G 2310/08 Details of timing specific for flat panels, other than clock recovery
• CPC Class Codes: G09G 2320/0247 Flicker reduction other than flicker reduction circuits used for single beam cathode-ray tubes
• CPC Class Codes: G09G 2320/0646 Modulation of illumination source brightness and image signal correlated to each other
• 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
• CPC Class Codes: G09G 3/3426 the different display panel areas being distributed in two dimensions, e.g. matrix
• CPC Class Codes: G09G 3/3611 Control of matrices with row and column drivers

Abstract

The present invention provides an illuminating apparatus locally reducing light intensity without depending on the configuration of a light source itself. An illuminating apparatus used as a backlight of a display apparatus having a liquid crystal display panel with a pair of first polarizers, including a light source and a liquid crystal light control panel. The liquid crystal light control panel has a pair of second polarizers and suppresses amount of transmission of light from the light source, thereby allows the light from the light source to have such a light intensity distribution along a plane that light intensity is locally reduced. The polarization degree in the second polarizers is optimized so that transmission light amount ratio of the second polarizers is lower than that of the first polarizers.

Claims

1. An illuminating apparatus used as a backlight of a display apparatus having a liquid crystal display panel with a pair of first polarizers, comprising:

a light source; and

a liquid crystal light control panel having a pair of second polarizers and suppressing amount of transmission of light from the light source, so as to allow the light from the light source to have such a light intensity distribution along a plane that light intensity is locally reduced,

wherein each of the first polarizers has a first polarizing layer having a first thickness and each of the second polarizers has a second polarizing layer having a second thickness, in which the second thickness has a value less than that of the first thickness so as to cause a polarization degree of the second polarizers to be less than that of the first polarizers such that the transmission light amount ratio of the second polarizers is lower than that of the first polarizers.

2. The illuminating apparatus according to claim 1, wherein the polarization degree in the second polarizers is about 99.5 (%) or less to control the transmission light amount ratio of the second polarizers to be lower than that of the first polarizers.

3. The illuminating apparatus according to claim 1, wherein

the polarizing layer of each of the second polarizers is impregnated with iodine and,

impregnation amount of iodine in each of the second polarizers is optimized to control the transmission light amount ratio of the second polarizers to be lower than that of the first polarizers.

4. The illuminating apparatus according to claim 1, wherein

the liquid crystal light control panel is divided into a plurality of divisional regions in a two-dimensional matrix, and

the amount of transmission of light from the light source is selectively suppressed on a divisional region unit basis to allow the light intensity in the plane to be locally reduced on the divisional region unit basis.

5. A display apparatus comprising:

an illuminating device including a light source and a liquid crystal light control panel; and

a display section including a liquid crystal display panel with a pair of first polarizers and displaying a video image based on an input video signal through using illumination light from the illuminating apparatus as display light, wherein

the liquid crystal light control panel has a pair of second polarizers and suppressing amount of transmission of light from the light source, so as to allow the light from the light source to have such a light intensity distribution along a plane that light intensity is locally reduced, and

each of the first polarizers has a first polarizing layer having a first thickness and each of the second polarizers has a second polarizing layer having a second thickness, in which the second thickness has a value less than that of the first thickness so as to cause a polarization degree of the second polarizers to be less than that of the first polarizers such that transmission light amount ratio of the second polarizers is lower than that of the first polarizers.

6. The display apparatus according to claim 5, wherein

the liquid crystal light control panel is divided into a plurality of divisional regions in a two-dimensional matrix, and

the amount of transmission of light from the light source is selectively suppressed on a divisional region unit basis to allow the light intensity in the plane to be locally reduced on the divisional region unit basis in accordance with the input video signal.

7. The display apparatus according to claim 6, further comprising:

a storing section storing light intensity distribution data which represents the light intensity distribution which appears when the amount of transmission of light from the light source is selectively suppressed in some of the plurality of divisional regions in the liquid crystal light control panel; and

a correcting section correcting luminance of the input video signal on the basis of the light intensity distribution data stored in the storing section and generating a video image to be displayed on the display section.

8. The display apparatus according to claim 5, wherein a frame frequency for displaying a video image in the display section and a drive frequency of the liquid crystal light control panel are completely synchronized with each other, or the two frequencies have completely different values so that no visual beat is generated.