Illumination device and liquid crystal display apparatus including same
First Claim
1. An illumination device, comprising:
- a rectangular light guide means,four linear light sources disposed along four sides of the rectangular light guide means so as to surround the light guide means,a reflection means disposed behind the light guide means so that light issued from the linear light sources is transmitted through the light guide means and reflected by the reflection means to be emitted from the light guide means in a forward direction, anda luminance distribution-adjusting means for reflecting light transmitted through the light guide means and disposed along the light guide means with a distribution density which varies continuously at a changing rate free from discontinuity so as to adjust the luminance distribution of the light emitted from the light guide means in a forward direction and so as to emit a substantially uniform distribution of light from the light guide means,wherein said luminance distribution-adjusting means is disposed between the light guide means and the reflection means with a distribution density that is highest in the vicinity of a central portion of the light guide means and decreases as a position approaches the edges of the light guide means to provide an iso-distribution density curve forming a closed loop with no angles.
1 Assignment
0 Petitions
Accused Products
Abstract
An illumination device includes a plurality of linear light sources disposed with a prescribed spacing therebetween, a light guide means disposed between or among the linear light sources, and a reflection means disposed behind the light guide means so that light issued from the linear light sources is transmitted through the light guide means and reflected by the reflection means to be emitted in a direction forward from the light guide means. Further, a luminance distribution-adjusting means for reflecting light transmitted through the light guide means is disposed along the light guide means in a disribuption density which varies continuously at a changing rate free from discontinuity so as to adjust the luminance distribution of the light emitted in the direction forward from the light guide means. The illumination device may be suitably used as a backlight behind a liquid crystal panel to provide a liquid crystal display apparatus having improved display qualities.
46 Citations
17 Claims
-
1. An illumination device, comprising:
-
a rectangular light guide means, four linear light sources disposed along four sides of the rectangular light guide means so as to surround the light guide means, a reflection means disposed behind the light guide means so that light issued from the linear light sources is transmitted through the light guide means and reflected by the reflection means to be emitted from the light guide means in a forward direction, and a luminance distribution-adjusting means for reflecting light transmitted through the light guide means and disposed along the light guide means with a distribution density which varies continuously at a changing rate free from discontinuity so as to adjust the luminance distribution of the light emitted from the light guide means in a forward direction and so as to emit a substantially uniform distribution of light from the light guide means, wherein said luminance distribution-adjusting means is disposed between the light guide means and the reflection means with a distribution density that is highest in the vicinity of a central portion of the light guide means and decreases as a position approaches the edges of the light guide means to provide an iso-distribution density curve forming a closed loop with no angles. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 17)
-
-
9. An illumination device, comprising:
-
a rectangular light guide means; four linear sources disposed along four sides of the rectangular light guide means so as to surround the light guide means; a reflection means disposed behind the light guide means so that light issued from the linear light sources is transmitted through the light guide means and reflected by the reflection means to be emitted from the light guide means in a forward direction; and a luminance distribution-adjusting means for reflecting light transmitted through the light guide means and disposed along the light guide means with a distribution density which varies continuously at a changing rate free from discontinuity so as to adjust the luminance distribution of the light emitted from the light guide means in a forward direction and so as to emit a substantially uniform distribution of light from the light guide means, wherein said luminance distribution-adjusting means is disposed on a front side of the light guide means and opposite the reflection means with a distribution density that is lowest in the vicinity of a central portion of the light guide means and increases as a position approaches the edges of the light guide means to provide an iso-distribution density curve forming a closed loop with no angles. - View Dependent Claims (10, 11, 12)
-
-
13. An illumination device, comprising:
-
a light guide member comprising an almost rectangular transparent sheet material having four sides, four linear light sources each disposed along one of the four sides of the light guide member, a reflection plate disposed on a rear side of the light guide member, and a reflection pattern disposed between the light guide member and the reflection plate comprising a plurality of dots disposed in a varying distribution density such that the distribution density is low in the vicinity of the linear light sources and increases as it becomes further from the linear light sources, the distribution density assuming a maximum without providing a discontinuity in a distribution density-varying rate along a horizontal line extending between a pair of opposite linear light sources, the distribution density providing an iso-distribution density curve on a rear face of the light guide member which forms an angle-free closed loop having a shape substantially similar to the contour of the light-emission face of the light guide member, whereby light issued from the linear light sources is transmitted through the light guide member and reflected by the reflection plate and the reflection pattern to be emitted from the light guide member in a forward direction.
-
-
14. An illumination device, comprising:
-
a light guide member comprising an almost rectangular transparent sheet material having four sides, four linear light sources each disposed along one of the four sides of the light guide member, a reflection plate disposed on a rear side of the light guide member, and a reflection pattern disposed on a front side of the light guide member comprising a plurality of dots disposed in a varying distribution density such that the distribution density is high in the vicinity of the linear light sources and decreases as it becomes further from the linear light sources, the distribution density assuming a minimum without providing a discontinuity in a distribution density-varying rate along a horizontal line extending between a pair of opposite linear light sources, the distribution density providing an iso-distribution density curve on a light-emission face of the light guide member which forms an angle-free closed loop having a shape substantially similar to the contour of the light-emission face of the light guide member, whereby light issued from the linear light sources is transmitted through the light guide member and reflected by the reflection plate and the reflection pattern to be emitted from the light guide member in a forward direction.
-
-
15. An illumination device, comprising:
-
a rectangular light guide means, four linear light sources disposed along four sides of the rectangular light guide means so as to surround the light guide means, a reflection means disposed behind the light guide means so that light issued from the linear light sources is transmitted through the light guide means and reflected by the reflection means to be emitted from the light guide means in a forward direction, and a luminance distribution-adjusting means for reflecting light transmitted through the light guide means and disposed along the light guide means with a distribution density which varies continuously at a changing rate free from discontinuity so as to adjust the luminance distribution of the light emitted from the light guide means in a forward direction and so as to emit a substantially uniform distribution of light from the light guide means, wherein said luminance distribution-adjusting means is disposed the light guide means and the reflection means with a distribution density that is highest in the vicinity of a central portion of the light guide means and decreases as a position approaches the edges of the light guide means, except at a corner of the light guide means wherein the distribution density increases, to provide an iso-distribution density curve forming a closed loop with no angles.
-
-
16. An illumination device, comprising:
-
a rectangular light guide means, four linear light sources disposed along four sides of the rectangular light guide means so as to surround the light guide means, a reflection means disposed behind the light guide means so that light issued from the linear light sources is transmitted through the light guide means and reflected by the reflection means to be emitted from the light guide means in a forward direction, and a luminance distribution-adjusting means for reflecting light transmitted through the light guide means and disposed along the light guide means with a distribution density which varies continuously at a changing rate free from discontinuity so as to adjust the luminance distribution of the light emitted from the light guide means in a forward direction and so as to emit a substantially uniform distribution of light from the light guide means, wherein said luminance distribution-adjusting means is disposed on a front side of the light guide means and opposite the reflection means with a distribution density that is lowest in the vicinity of a central portion of the light guide means and increases as a position approaches the edges of the light guide means, except at a corner of the light guide means wherein the distribution density decreases, to provide an iso-distribution density curve forming a closed loop with no angles.
-
Specification