Illumination device, light guide plate, surface light source device and illumination unit

• US 20070041171A1
• Filed: 07/20/2006
• Published: 02/22/2007
• Est. Priority Date: 07/20/2005
• Status: Active Grant

• Current Assignee: Enplas Corporation
• Original Assignee: Enplas Corporation
• Inventors: Ohkawa, Shingo
• Granted Patent: US 7,703,936 B2
• Time in Patent Office: Days
• US Class Current: 362/97.200
• CPC Class Codes: G02F 1/133604 with lamps
• CPC Class Codes: G02F 1/133605 including specially adapted reflectors

Abstract

Illumination device/surface light source device provides an increased and uniformalized emission brightness. A plurality of fluorescent lamps are disposed in parallel with each other at a certain interval between a reflection sheet and light flux control member. A back face of the light flux control member is provided with recesses and curved surfaces connected thereto at locations corresponding to those of the fluorescent lamps. Each recess consists of first and second light entering surfaces. Each curved surface consists of third and forth light entering surfaces. A bulging configuration is formed around boundary between each recess and each curved surface. The first light entering surface causes light coming to areas corresponding to the fluorescent lamps, included in the light reaching a light diffusing member, to diverge smoothly. The second light entering surface and convex curved surface causes light coming to areas, which do not correspond to the fluorescent lamps, adjacent to areas corresponding to the fluorescent lamps to have light intensity increased up to generally the same as that of the light coming to the areas corresponding to the fluorescent lamps.

Claims

1. An illumination device comprising:

a reflection member;

a light flux control member disposed along and separated from said reflection member; and

a plurality of linear primary light sources disposed between said reflection member and said light flux control member parallel with each other at intervals,

wherein said light flux control member has a back face directed to said reflection member in order to receive light from said primary light sources and an emission face directed oppositely to said back face in order to cause said light received to be transmitted, deflected and emitted; and

at least one of said back face and said emission face is provided with a plurality of recesses and curved surfaces,

each of said recesses having a location correspond to that of one of said primary light sources and extending in a longitudinal direction of said one of said primary light source, and

said curved surfaces being located adjacent to said recesses and configured as to cause said light flux control member to decrease in thickness away from said recesses, respectively.

3. An illumination unit comprising:

an illumination device as claimed in claim 1;

and

a member-to-be-illuminated irradiated by an illumination light outputted from said illumination device.

2. A surface light source device comprising:

a reflection member;

a light flux control member disposed along and separated from said reflection member;

a plurality of linear primary light sources disposed between said reflection member and said light flux control member parallel with each other at intervals; and

a plate-like light diffusion member,

wherein said light flux control member has a back face directed to said reflection member in order to receive light from said primary light sources and an emission face directed oppositely to said back face in order to cause said light received to be transmitted, deflected and emitted; and

at least one of said back face and said emission face is provided with a plurality of recesses and curved surfaces; and

said light diffusion member is disposed along said emission face in order to diffuses light emitted from said emission face,

each of said recesses having a location correspond to that of one of said primary light sources and extending in a longitudinal direction of said one of said primary light source,

said curved surfaces being located adjacent to said recesses and configured as to cause said light flux control member to decrease in thickness away from said recesses, respectively.

4. An illumination unit comprising:

a surface light source device as claimed in claim 2;

and

a member-to-be-illuminated irradiated by an illumination light outputted from said illumination device.