Low profile backlighting using LEDs

• US 7,559,664 B1
• Filed: 12/27/2004
• Issued: 07/14/2009
• Est. Priority Date: 12/27/2004
• Status: Active Grant

• Current Assignee: John V. Walleman
• Original Assignee: John V. Walleman
• Inventors: Rampton, Malan D., Walleman, John V.
• Primary Examiner(s): CARIASO, ALAN B
• Application Number:
  US11/020,110
• Time in Patent Office: 1,660 Days
• Field of Search: 362/84, 362/97, 362/230, 362/231, 362235-237, 362/240, 362/29, 362/30, 405/42, 405/43, 405/44, 405/64, 407/14, 407/16, 405/46
• US Class Current: 362/84
• CPC Class Codes: G09F 13/04 Signs, boards or panels, illuminated from behind the insignia
• CPC Class Codes: G09F 13/18 Edge-illuminated signs

Abstract

A low profile backlighted display includes a translucent display piece having a viewable surface. A casing is configured expose at least a portion of the viewable surface. The display piece may have a perimeter, and the casing may conform generally to the perimeter of the display piece. An illumination cavity is configured within the casing and is behind the viewable surface of the display piece. A plurality of light emitting diodes (LEDs) are located within the illumination cavity. At least one of the LEDs may be configured to backlight the display piece, and one or more of the LEDs may be configured to emit essentially only non-visible light. A passive element may be configured to backlight the viewable surface when excited by non-visible light from the non-visible light LEDs. The plurality of LEDs and the passive element collectively provide an essentially uniform back light illumination of the viewable surface.

Claims

1. A display, comprising:

a low profile backlighted display assembly forming a cabinet door or a picture frame, comprising;

a translucent display piece having a viewable surface and a perimeter;

a casing configured to conform generally to the perimeter of the display piece while exposing at least a portion of the viewable surface;

an illumination cavity configured within the casing and behind the viewable surface of the display piece; and

a plurality of light emitting diodes (LEDs) located within the illumination cavity and configured to provide an essentially uniform back light illumination of the viewable surface, wherein;

the plurality of LEDs are configured to provide a non-uniform pattern density that compensates for a luminous intensity that decreases with increasing distance from the plurality of LED,

the plurality of LEDs comprise first LEDs and second LEDs,

the first LEDs and the second LEDs are positioned opposite each other, and configured to illuminate toward each other, within an illumination plane, and

a first axis of illumination of the first LEDs is offset from a second axis of illumination of the second LEDs.

2. The display of claim 1 wherein a placement of the first LEDs is staggered relative to a placement of the second LEDs causing the first axis of illumination of the first LEDs to be offset from the second axis of illumination of the second LEDs.

3. The display of claim 1 wherein the first and second axes of illumination are essentially parallel to each other.

4. The display of claim 1 wherein the plurality of LEDs comprise at least first LEDs having a first emission angle and second LEDs having a second emission angle.

5. The display of claim 1 wherein the plurality of LEDs comprise at least first LEDs having a first luminous output and second LEDs having a second luminous output.

6. A display, comprising:

a low profile backlighted display assembly forming a cabinet door or a picture frame, comprising;

a translucent display piece having a viewable surface and a perimeter;

a casing configured to conform generally to the perimeter of the display piece while exposing at least a portion of the viewable surface;

an illumination cavity configured within the casing and behind the viewable surface of the display piece, wherein the illumination cavity includes an illumination perimeter that conforms generally to the perimeter of the display piece;

a plurality of light emitting diodes (LEDs) located within the illumination cavity and configured to provide an essentially uniform back light illumination of the viewable surface, the LEDs comprising first LEDs that emit perceptible white light and second LEDs that emit essentially only non-visible light, wherein;

at least some of the plurality of LEDs are fixed relative to one or more portions of the illumination perimeter to project light away from the illumination perimeter, and

at least one of the plurality of LEDs is mounted at a non-perpendicular angle to the portion of the illumination perimeter to which it is affixed so as to enhance illumination uniformity,

a passive element configured to provide backlight illumination of the viewable surface when excited by non-visible light emitted by the second LEDs.