SURFACE LIGHT SOURCE DEVICE

• US 20020057562A1
• Filed: 03/31/1997
• Published: 05/16/2002
• Est. Priority Date: 03/29/1996
• Status: Active Grant

• Current Assignee: Enplas Corporation, Yasuhiro Koike
• Original Assignee: Enplas Corporation, Yasuhiro Koike
• Inventors: MASAKI, KAYOKO, SASAKO, HIROMI
• Granted Patent: US 6,641,274 B2
• Time in Patent Office: Days
• US Class Current: 362/31
• CPC Class Codes: G02B 6/0016 Grooves, prisms, gratings, scattering particles or rough surfaces
• CPC Class Codes: G02B 6/0046 Tapered light guide, e.g. wedge-shaped light guide
• CPC Class Codes: G02B 6/0053 Prismatic sheet or layer; Brightness enhancement element, sheet or layer
• CPC Class Codes: G02B 6/0055 Reflecting element, sheet or layer
• CPC Class Codes: G02B 6/0088 of the light guide or other optical sheets in the package

Abstract

An improved surface light source device applicable to back lighting of a liquid display. In the surface light source device, a plate-shaped optical block (15) is disposed along an emitting surface of a plate-shaped optical member (11), to which illumination light is to be supplied from a primary light source (3), and has on at least one of its outer and inner sides a directivity modifying surface for modifying directivity of illumination light emitted from the emitting surface. Directivity modifying surface occupies at least part of the whole area of the optical block except a predetermined range (AR2) from a position aligning to the incidence surface of the plate-shaped optical member (11). The optical block (15) and the plate-shaped optical member (11) may be held in a unitary form by a holding mechanism formed integrally with the optical block (15) and/or the plate-shaped optical member (11). One end of a reflection member about the primary light source (3) may be pinched between the optical block (15) and the plate-shaped optical member (11).

Claims

1. A surface light source device comprising:

a plate-shaped optical member;

a rod-shaped light source disposed near an incidence surface of said plate-shaped optical member;

a plate-shaped optical block disposed along an emitting surface of said plate-shaped optical member,

said optical block having on at least one of its outer and inner sides a directivity modifying surface for modifying directivity of illumination light emitted from said emitting surface of said plate-shaped optical member, said directivity modifying surface including a repetition of inclined surfaces through at least part of its whole area except a predetermined range from a position aligning to said incidence surface of said plate-shaped optical member.

2. A surface light source device according to claim 1, further comprising a reflection member disposed about said rod-shaped light source, one end of said reflection member being pinched between said optical block and said plate-shaped optical member.

3. A surface light source device according to claim 1 or 2, further including a holding mechanism which is integrally formed with said optical block and/or said plate-shaped optical member and holds said optical block and said plate-shaped optical member in a unitary form.

4. A surface light source device comprising:

a plate-shaped optical member;

a rod-shaped light source disposed near an incidence surface of said plate-shaped optical member;

a plate-shaped optical block disposed along an emitting surface of said plate-shaped optical member;

a reflection member disposed about said rod-shaped light source, one end of said reflection member being pinched between said optical block and said plate-shaped optical member,

said optical block having on at least one of its outer and inner sides a directivity modifying surface for modifying directivity of illumination light emitted from said emitting surface of said plate-shaped optical member.

5. A surface light source device comprising:

a plate-shaped optical member;

a rod-shaped light source disposed near an incidence surface of said plate-shaped optical member;

a plate-shaped optical block disposed along an emitting surface of said plate-shaped optical member and having on at least one of outer and inner sides a directivity modifying surface for modifying directivity of illumination light emitted from said emitting surface of said plate-shaped optical member,

said directivity modifying surface including a repetition of inclined surfaces through at least part of its whole area except a predetermined range from a position aligning to said incidence surface of said plate-shaped optical member; and

a holding mechanism which is integrally formed with said optical block and/or said plate-shaped optical member and holds said optical block and said plate-shaped optical member in a unitary form.