Patent ID: 7448783

Claim:
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.