Emission device

• US 20070268722A1
• Filed: 12/19/2006
• Published: 11/22/2007
• Est. Priority Date: 12/19/2005
• Status: Active Grant

• Current Assignee: Enplas Corporation
• Original Assignee: Enplas Corporation
• Inventors: Ohkawa, Shingo
• Granted Patent: US 7,448,783 B2
• Time in Patent Office: Days
• US Class Current: 362/623
• CPC Class Codes: F21V 13/04 the elements being reflectors and refractors for vehicle rear lights F21S43/40
• CPC Class Codes: F21V 5/04 of lens shape
• CPC Class Codes: F21V 7/0091 using total internal reflection
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: G02B 19/0028 refractive and reflective surfaces, e.g. non-imaging catadioptric systems
• CPC Class Codes: G02B 19/0061 the light source comprising a LED semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission H01L33/00
• CPC Class Codes: H01L 33/58 Optical field-shaping elements
• CPC Class Codes: H01L 33/60 Reflective elements

Abstract

Provided is a light emitting device having an inner-propagation-medium which caused directivity-to-optical-axis-direction to be relaxed. Light of a LED travels in the inner-propagation-medium, being emitted from an inside area of or outside area in a lens surface directly or via an inclined reflection face. A light emitter provides an output light having an intensity profile with a half-intensity-angular-range not greater than 20°, which expresses directivity of the output light. The outside area in the lens surface performs a traveling-direction-expanding-function which is not only relatively intensive as compared that performed by the inside area in the lens surface, and but also relatively intensive as compared that performed in an imaginary case where the outside area gives a planar surface perpendicular to an optical axis. The half-intensity-angular-range of the intensity profile of the light emitting device is not smaller than 30° with respect to the optical axis and not greater than 70°. The lens face may be formed of one or more convex surfaces in the outside area.

Claims

1. An emission device comprising:

a light emitter composed of a point-like light source and a reflection means providing a reflection face arranged on a light outgoing side of said point-like light source as to surround said point-like light source sideways; and

an inner-propagation-medium in which output light of said light emitter inner-propagates,

wherein a first intensity profile expressing directivity of output light of said light emitter has a half-intensity-angular-range which is not greater than 20°

with respect to an optical axis direction giving the maximum intensity, and said inner-propagation-medium has an emission face for emitting said output light after inner propagation, said emission face having an inside area extending around a position at which said emission face crosses said optical axis and an outside area extending as to surround said inside area;

said reflection face being inclined as to reflect light, which is emitted from said point-like light source and reaches said reflection face via inner-propagation-medium, mainly toward said outside area;

said inside area providing a lens surface which has a first traveling-direction-expanding-function for expanding traveling directions of light which is emitted from said point-like light source and reaches said inside area via inner-propagation-medium without impinging on said reflection face;

said outside area providing another lens surface which has a second traveling-direction-expanding-function for expanding traveling directions of light which is emitted from said point-like light source and reaches said outside area after being reflected by said reflection face via inner-propagation-medium;

said second traveling-direction-expanding-function is stronger than a traveling-direction-expanding-function which is effected in an imaginary case where said outside area is formed of a flat face perpendicular to said optical axis;

said first traveling-direction-expanding-function is weaker than said second traveling-direction-expanding-function; and

,

a second intensity profile expressing directivity of a total output light composed of light emitted from said inside area and light emitted from said outside area has a half-intensity-angular-range which is not smaller than 30° and

not greater than 70°

with respect to said optical axis direction.

2. An emission device according to claim 1, wherein said outside area provides at least one concave-like lens surface.

3. An emission device according to claim 1, wherein said outside area provides at least one convex-like lens surface.