Surface Light Source and Electrically Illuminated Signboard

• US 20080047181A1
• Filed: 06/29/2005
• Published: 02/28/2008
• Est. Priority Date: 07/06/2004
• Status: Active Grant

• Current Assignee: Yoshihiro Sakai, ZYCC Corporation
• Original Assignee: Asagicreate Co., Ltd., Yoshihiro Sakai
• Inventors: Sakai, Yoshihiro
• Granted Patent: US 7,637,045 B2
• Time in Patent Office: Days
• US Class Current: 40/546
• CPC Class Codes: G09F 13/04 Signs, boards or panels, illuminated from behind the insignia
• CPC Class Codes: G09F 13/0409 Arrangements for homogeneous illumination of the display surface, e.g. using a layer having a non-uniform transparency arrangements of reflectors G09F13/14
• CPC Class Codes: Y10S 362/80 Light emitting diode
• CPC Class Codes: Y10S 362/812 Signs

Abstract

There are provided a surface light source having uniform and high brightness independently whether the light source is small or large while using semiconductor light emitting devices (LEDs), and an electrically illuminated signboard using the surface light source, which is thin and capable of uniform display and which operates with low electricity consumption. LEDs (12) of a dome type are arranged on four corners at a bottom surface of a box body (11) of a tray shape whose bottom surface is quadrilateral, whose upper side is open, on an inner surface of which a light reflection member (11b) is provided, and whose side walls (11c) are inclined outward. The LEDs (12) are arranged so as to mainly irradiate a region between a vertical plane on a diagonal line (N) of the bottom surface and one side wall (11c), and the region irradiated by each of the LEDs (12) of the dome type arranged on the four corners rotates individually and sequentially in a specific direction (same direction) in the box body (11). One or more of the surface light source units are arranged to construct an electrically illuminated signboard.

Claims

1. A surface light source unit comprising

a box body of a tray shape, whose bottom surface is quadrilateral and has a flat surface, whose upper side is open, on an inner surface of which a light reflection member is provided, and whose four side walls are inclined outward with a same angle, and

semiconductor light emitting devices of a dome type which are provided on at least opposite two corners of the bottom surface of the box body so as to mainly irradiate a region between a vertical plane on a diagonal line of the bottom surface and one side wall, the region being about a half space of the box body, and so as not to stick out from the opening end portions so that the opening end portions adjacent box bodies are brought into close contact with each other in case of arranging the box bodies side-by-side,

wherein the semiconductor light emitting devices provided on at least two corners of the bottom surface of the box body are arranged in places of rotational symmetry as to a center of the box body and the region irradiated by each of the light emitting devices moves in a manner of the rotational symmetry.

2. The surface light source unit according to claim 1, wherein a light diffusion member is provided on a surface of an opening surface side of the box body.

3. The surface light source unit according to claim 1, wherein two light emitting devices are arranged on each corner of at least the two corners, and wherein a set of the two light emitting devices are arranged so that each region mainly irradiated by the two light emitting devices is a different half space as to a diagonal line passing the corner where the two light emitting devices are provided.

4. A surface light source comprising:

a plurality of surface light source units provided side-by-side, and

a light diffusion member on or over the plurality of surface light source units so as to cover the plurality of surface light source units,

wherein each of the plurality of surface light source units comprising;

a box body of a tray shape, whose bottom surface is quadrilateral and has a flat surface, whose upper side is open, on an inner surface of which a light reflection member is provided, and whose four side walls are inclined outward with a same angle, and

semiconductor light emitting devices of a dome type which are provided on at least opposite two corners of the bottom surface of the box body so as to mainly irradiate a region between a vertical plane on a diagonal line of the bottom surface and one side wall, the region being about a half space of the box body, and so as not to stick out from the opening end portions so that the opening end portions adjacent box bodies are brought into close contact with each other in case of arranging the box bodies side-by-side.

5. The surface light source according to claim 4, wherein a plurality of surface light source units are arranged side-by-side so as to prevent adjacent two side walls of adjacent two surface light source units from being exposed in the same height at a surface, by forming a side wall of one surface light source unit lower than a side wall of the other surface light source unit in a height of the side wall at the opening end portion at a place of adjoining each other.

6. The surface light source according to claim 5, wherein a light reflection sheet is stuck on an inner surface of the lower side wall of the one surface light source unit so as to overhang from a top end surface of the other side wall, thereby to cover the top end surface of the other side wall.

7. An electrically illuminated signboard comprising:

a surface light source formed with one or more surface light source units,

a light diffusion plate provided through a certain distance over the surface light source and

a display panel provided on the light diffusion plate,

wherein each of the one or more surface light source units comprising;

a box body of a tray shape, whose bottom surface is quadrilateral and has a flat surface, whose upper side is open, on an inner surface of which a light reflection member is provided, and whose four side walls are inclined outward with a same angle, and

semiconductor light emitting devices of a dome type which are provided on at least opposite two corners of the bottom surface of the box body so as to mainly irradiate a region between a vertical plane on a diagonal line of the bottom surface and one side wall, the region being about a half space of the box body, and so as not to stick out from the opening end portions so that the opening end portions adjacent box bodies are brought into close contact with each other in case of arranging the box bodies side-by-side.

8. The electrically illuminated signboard according to claim 7, wherein the surface light source unit is fixed by fixing a bottom surface of the surface light source unit to a fixing metal part provided on a bottom surface of a casing through a circuit board.

9. The electrically illuminated signboard according to claim 7, wherein a plurality of surface light source units are arranged side-by-side and wherein one light diffusion member is arranged so as to cover the plurality of surface light source units.

10. The electrically illuminated signboard according to claim 7, wherein two light emitting devices are arranged on each corner of at least opposite two corners, and wherein a set of the two light emitting devices are arranged so that each region mainly irradiated by the two light emitting devices is a different half space as to a diagonal line passing the corner where the two light emitting devices are provided.

11. The electrically illuminated signboard according to claim 7, wherein a plurality of surface light source units are arranged side-by-side so as to prevent adjacent two side walls of adjacent surface light source units from being exposed in the same height at a surface, by forming a side wall of one surface light source unit lower than a side wall of the other surface light source unit in a height of the side wall at the opening end portion at a place of adjoining each other.

12. The electrically illuminated signboard according to claim 11, wherein a light reflection sheet is stuck on an inner area of the lower side wall of the one surface light source unit so as to overhang from a top end area of the other side wall, thereby to cover the top end surface of the other side wall.