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US 7,621,657 B2Granted
Light emitting device, surface light source device, display and light flux control member
AssigneeEnplas Corporation
InventorShingo Ohkawa
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AssigneeEnplas Corporation
InventorShingo Ohkawa
Estimating the term…
Light from light emitting element enters into a flux control member through a recess on an inner face of the light flux control member, being emitted from an emission control face (outer face). At least so far as light falls within a half-intensity-angular-range, the light satisfies Condition 1 ((θ5/θ1)>1 except for light in the vicinity of a normal direction of the emission control face) and Condition 2 (Value of θ5/θ1>1 gets smaller gradually with increasing of θ1). It is noted that θ1, θ5 are angles made at being inner-incident to the emission control face and at being emitting from the same, respectively. The emission control face has a planar outline shape which is anisotropic around optical axis L, thereby causing value of θ5 /θ1 to have a change depending on direction angle φ around optical axis L, with the result that highly uniform light is supplied to a required anisotropic irradiation range.
A light emitting device comprising:
A light flux control member which allows light from a light emitting element to be inputted thereto and emits direction-controlled light, comprising:
Dependencies are inferred from the claim text.
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From the US filing history. Foreign family members aren’t listed.
The light source comprising a LED: in the form of an LED array
Prisms: prism arrays
Characterised by the optical means employed: refractive and reflective surfaces, e.g. non-imaging catadioptric systems
For use with a light source: the light source comprising a LED
About 5 months of term left · ends 13 Mar 2027 (estimated)
1. Field of Invention
The present invention relates to a light emitting device, surface light source device, display and a light flux control member, being applied, for example, to a light emitting device or surface light source device 2 for backlighting a display member such as LCD-panel, or to a display composed of a display member and such light emitting device or surface light source device.
Further, the present invention is also applied to a light flux control member used in devices as above. More concretely, a light emitting device, surface light source device, display and light flux control member are employable in displays used as TV-monitors or monitors for personal computers and in backlighting arrangements in the devices. In addition, applications to interior illumination or various illumination are possible.
FIG. 1 is a plan view of a surface light source device in accordance with a first embodiment of the present invention and a display employing the surface light source device, with a member-to-be-illuminated (displaying member) being not show;
FIG. 2 is a cross sectional diagram for illustrating cross sections of the display along lines X1-X1 and X3-X3 in FIG. 1;
FIG. 3 is a partial cross section view of the display in the first embodiment, illustrating parameters (such as θ1, θ3 , θ5 ) in connection with an optical axis of a light emitting element (LED);
(Skeleton of Surface Light Source Device 2 and Display)
FIGS. 1 to 3 illustrate display 1 surface light source device 2 included in display 1. FIG. 1 is a plan view of surface light source device 2 and display 1, with a member-to-be-illuminated (displaying member) being omitted. FIG. 2 is a cross sectional diagram for illustrating cross sections along lines XI-XI and X3-X3 in FIG. 1. FIG. 3 is a partial cross section view of display 1 in the, illustrating parameters (such as θ1 , θ3 , θ5) in connection with a datum optical axis L.
It is noted that “datum optical axis L of light emitting device 9” is defined as “a light traveling direction at a center of a three-dimensional emission flux from light emitting device 9”. On the other hand, “optical axis of light emitting element (point-like light source) 4” is defined as “a light traveling direction at a center of a three-dimensional emission flux from light emitting element 4”. In this embodiment, “datum optical axis L of light emitting device 9” accords with “optical axis of light emitting element 4”. Thus datum optical axis L may be called optical axis L in the description hereafter.