Collector for an LED array

• US 4,767,172 A
• Filed: 03/11/1985
• Issued: 08/30/1988
• Est. Priority Date: 01/28/1983
• Status: Expired due to Term

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Martin, James P., Nichols, Virginia R., Hubble, Fred F. III
• Primary Examiner(s): Braun, Fred L.
• Application Number:
  US07/709,973
• Time in Patent Office: 1,268 Days
• Field of Search: 355/1, 355/3 R, 355/67, 350/96.18, 350/443, 350/444, 362/800
• US Class Current: 385/146
• CPC Class Codes: F21V 7/0091 using total internal reflection
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: G02B 6/4206 Optical features G02B6/4207, G02B6/421 take precedence
• CPC Class Codes: G02B 6/4214 the intermediate optical element having redirecting reflective means, e.g. mirrors, prisms for deflecting the radiation from horizontal to down- or upward direction toward a device G02B6/4246 takes precedence
• CPC Class Codes: G02B 6/4249 comprising arrays of active devices and fibres
• CPC Class Codes: G02B 6/425 Optical features semiconductor laser arrays H01S5/40; hybrid LED arrays H01L25/0753; monolithic LED arrays H01L27/153
• CPC Class Codes: G03G 15/047 for discharging non-image areas
• CPC Class Codes: G03G 2215/0451 Light-emitting array or panel

Abstract

A light collector for an LED array for efficiently collecting and collimating light emitting from the LEDs and projecting the light into an optical wave guide which directs that light onto a photoreceptor surface. Each LED is centered in a hemispherical cavity in the collector array in order that radiation from the LED enters the collector essentially unrefracted. The collector array provides a convex lens portion and a parabolic reflecting surface portion. Light that exits from the LED that is substantially perpendicular to the substrate supporting the LED is applied to the convex lens and is collimated. Light exiting substantially parallel to the substrate strikes a parabolic reflecting surface at greater than the critical angle and is also collimated. The two concentric collimated beams are combined and applied to the photoreceptor surface via a light pipe or optical wave guide secured to the collector.

Claims

1. A molded light collector for collimating the light rays emitting from a relatively wide emission light source for coupling to an optical wave guide, the light source being an LED mounted on a substrate, the light collector enclosing the LED and forming a hemispherical cavity around the LED, a portion of the light collector being integrally secured to the substrate, the light collector comprising

an optical wave guide,

a lens portion for collimating the light exiting from the light source substantially perpendicular to the substrate, and

a reflecting portion attached to the substrate for collimating the light exiting from the light source substantially parallel to the substrate, the hemispherical cavity forming an air pocket between the LED and the light collector wherein the collimated light beams are combined and applied to the optical wave guide.

2. The light collector of claim 1 in which the lens portion is a convex lens collimating the light exiting from the light source within an approximately 40°

cone relative to a perpendicular to the substrate.

3. The light collector of claim 1 wherein the reflecting portion is a parabolic reflector for collimating the light rays emanating from the light source at an angle from 45°

to 90°

relative to a perpendicular to the substrate.