Light guide panel and plane illuminator apparatus

• US 6,402,335 B1
• Filed: 09/07/2000
• Issued: 06/11/2002
• Est. Priority Date: 09/13/1999
• Status: Expired due to Term

• Current Assignee: Minebea Company Limited (MinebeaMitsumi Inc.)
• Original Assignee: Nippon Leiz Corporation
• Inventors: Nakane, Tadaaki, Kalantar, Kalil
• Primary Examiner(s): O'Shea, Sandra
• Assistant Examiner(s): Zeade, Bertrand
• Application Number:
  US09/657,287
• Time in Patent Office: 642 Days
• Field of Search: 362/31, 362/26, 362/27, 362/560, 362/330, 362/335, 362/339, 362/223, 362/559, 349/62, 349/64, 349/65
• US Class Current: 362/619
• CPC Class Codes: G02B 6/0036 2-D arrangement of prisms, protrusions, indentations or roughened surfaces
• CPC Class Codes: G02B 6/0061 to provide homogeneous light output intensity

Abstract

A light guide panel according to the present invention includes at least one set of mutually opposing incident end surface portions through which light from light sources is introduced, a front surface portion through which light introduced from the set of the incident end surface portions is emanated, a back surface portion positioned on the opposite side to the front surface portion, and many light deflection portions formed on at least one between the front surface portion and the back surface portion. The rate of the light deflection portion per unit area along the other incident end surface portion from the one incident end surface portion is set to be two Gaussian distributions, and the peak of the first Gaussian distribution is biased to the side of the one incident end surface portion, and the peak of the second Gaussian distribution is biased to the side of the other incident end surface portion. Thereby, the amount of light emanating from the center of the light guide panel is relatively increased, and distribution of the amount of light emanating from all the front surface portion of the light guide panel can be made uniform.

Claims

1. A light guide panel comprising:

at least one set of opposing incident end surface portions adapted to receive light from a light source;

a front surface portion from which the light when introduced from the set of incident end surface portions is emanated;

a back surface portion located on the opposite side to the front surface portion; and

a plurality of light deflection portions formed on at least one of the front surface portion or the back surface portion, the light deflection portions being configured to refract light when light passes therethrough,

wherein the concentration of said light deflection portions per unit area along the at least one of the front surface portion or back surface portion comprises a first Gauss distribution and a second Gauss distribution, and a peak of said first Gauss distribution is shifted toward one incident end surface portion while a peak of said second Gauss distribution is shifted toward the other incident end surface portion.

2. The light guide panel as claimed in claim 1 wherein said peak of said first Gauss distribution is more shifted toward the center of said light guide panel than toward the incident end surface portion.

3. The light guide panel as claimed in claim 1 wherein the first and second Gauss distributions are not overlapped in the center of the light guide panel.

4. The light guide panel as claimed in claim 1 wherein each of said light deflection portions includes a pair of vertical pyramids conical surfaces having a contour configuration of an isosceles triangle projected perpendicularly and rising substantially vertically from said front surface portion or said back surface portion, and an inclined conical surface inclined with respect to said front surface portion or said back surface portion such that a bottom side is parallel to said incident end surface portions.

5. The light guide panel as claimed in claim 1 wherein each of said light deflection portions is an indention formed as a part of a spherical surface with a predetermined radius of curvature in said back surface portion.

6. The light guide panel as claimed in claim 1 wherein said light guide panel is rectangular plate shaped, and there are provided two sets of mutually opposing incident end surface portions.

7. The light guide panel as claimed in claim 6 wherein said sets of the incident end surface portions intersect to each other in their opposing directions.

8. A plane illuminator apparatus comprising:

a light guide panel including a front surface portion configured to emanate light, a back surface portion located on the opposite side of the front surface portion, at least a set of opposing incident end surface portions, and a plurality of light deflection portions located on at least one of the front surface portion or the back surface portion, the light deflection portions being configured to refract light when light passes therethrough;

light sources for projecting light toward the at least a set of opposing incident end surface portions of the light guide panel; and

a light reflection sheet covering at least a portion of the back surface portion of the light guide panel,

wherein the concentration of said light deflection portions per unit area along the at least one of the front surface portion or the back surface portion comprises a first Gauss distribution and a second Gauss distribution, and the peak of said first Gauss distribution is shifted toward one incident end surface while the peak of said second Gauss distribution is shifted toward the other incident end surface portion.

9. The plane illuminator apparatus as claimed in claim 8 wherein said peak of said first Gauss distribution is more shifted toward the center of said light guide panel than toward the incident end surface portion.

10. The plane illuminator apparatus as claimed in claim 8 wherein the first and second Gauss distributions are not overlapped in the center of the light guide panel.

11. The plane illuminator apparatus as claimed in claim 8 wherein each of said plurality of light deflection portions includes a pair of vertical pyramids conical surfaces having a contour configuration of an isosceles triangle projected perpendicularly and rising substantially vertically from said front surface portion or said back surface portion, and an inclined conical surface inclined with respect to said front surface portion or said back surface portion such that a bottom side is parallel to said incident end surface portion.

12. The plane illuminator apparatus as claimed in claim 8 wherein each of the plurality of light deflection portions comprises an indention formed as a part of a spherical surface with a predetermined radius of curvature in said back surface portion.

13. The plane illuminator apparatus as claimed in claim 8 wherein said light guide panel is rectangular plate shaped, and there are provided two sets of mutually opposing incident end surface portions.

14. The plane illuminator apparatus as claimed in claim 13 wherein said sets of the incident end surface portions intersect to each other in their opposing directions.

15. A light guide panel adapted to receive light from a light, the light guide panel comprising:

a front surface, an opposing back surface, and a first incident surface extending therebetween, the first incident surface being adapted to receive light such that the light emanates from the front surface portion; and

a plurality of light deflection portions positioned on at least one of the front surface or the back surface, the light deflection portions being configured to refract light when light passes therethrough, wherein the concentration of the light deflection portions per unit area along the at least one front surface or back surface comprises at least one substantially Gauss distribution.

16. The light guide panel as recited in claim 15 wherein each of the plurality of light deflection portions has a pyramidal configuration comprising:

a pair of vertical surfaces, each having a configuration of an isosceles triangle, the pair of vertical surfaces projecting substantially perpendicularly from the front face or the back face; and

an inclined surface extending between the pair of vertical surfaces, the inclined surface having a top portion and a bottom portion, wherein the inclined surface is inclined with respect to the front face or back face such that the bottom portion is parallel to the first incident surface.

17. The light guide panel as recited in claim 16 wherein the inclined surface faces toward the first incident surface.

18. The light guide panel as recited in claim 16 wherein the inclined surface faces away from the first incident surface.

19. The light guide panel as claimed in claim 15 wherein each of the plurality of light deflection portions comprises an indention formed in the back surface, the indention having a spherical surface with a predetermined radius of curvature.

20. The light guide panel as claimed in claim 15 further comprising a second incident surface extending between the front surface and the back surface.

21. The light guide panel as claimed in claim 20 wherein the concentration of the light deflection portions per unit area along the at least one front surface or back surface comprises a first and second substantially Gauss distribution, the first Gauss distribution having a first peak and the second Gauss distribution having a second peak, the first peak and second peak being separated.