External light source for backlighting display

• US 5,550,715 A
• Filed: 12/10/1993
• Issued: 08/27/1996
• Est. Priority Date: 12/10/1993
• Status: Expired due to Term

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Palm, Inc. (TCL Technology Group Corp.)
• Inventors: Hawkins, Jeffrey C.
• Primary Examiner(s): Gromada, Denise L.
• Assistant Examiner(s): Cariaso, Alan B.
• Application Number:
  US08/165,363
• Time in Patent Office: 991 Days
• Field of Search: 359/48, 359/49, 359/50, 362/26, 362/27, 362/28, 362/31, 362/327, 362/328, 362/330, 362/157, 362/226, 362/812, 362/190, 362/191, 40/541, 40/564, 40/582, 40/583
• US Class Current: 362/630
• CPC Class Codes: G02B 6/0036 2-D arrangement of prisms, protrusions, indentations or roughened surfaces
• CPC Class Codes: G02B 6/0046 Tapered light guide, e.g. wedge-shaped light guide
• CPC Class Codes: G02B 6/0066 characterised by the light source being coupled to the light guide
• CPC Class Codes: G02B 6/0073 Light emitting diode [LED]

Abstract

A method and apparatus for backlighting a transflective display within a hand-held computing device. An external light source and a power supply, dedicated to the light source, shines light through an input in a side of a computing device. The light which shines through the input is directed through the display by a light directing means. Light is conducted by a light conducting panel positioned along the back surface of a transflective display upon which text and images may be presented. The light so conducted shines through the transflective display, allowing a user to see images presented on the display even in subdued ambient light. Removal of the light source has no impact on the operation of the computing device other than to remove light which may only be necessary for viewing the display in low ambient light conditions.

Claims

1. A display illuminating system for a computing device, comprising:

a. a case having a transflective display and a light transmitting input;

b. at least one light emitting element, positioned externally from the case and removably affixed thereto, for emitting light into the light transmitting input; and

c. a light directing element comprising a light conducting panel disposed within the case and positioned with respect to the light transmitting input and transflective display so as to receive light emitted by the light emitting element into the light transmitting input and directing such light through the transflective display, thereby illuminating the display.

2. The system of claim 1, further including a self-contained power source coupled to the light emitting element.

3. The system of claim 2, further including an electrical switch for selectively coupling the light emitting element and the self-contained power source.

4. The system of claim 2, wherein the self-contained power source is a battery.

5. The system of claim 1, wherein the light transmitting input comprises an opening in the case.

6. The system of claim 1, wherein the light conducting panel is a light pipe.

7. The system of claim 1, wherein the light conducting panel is thicker at a proximal end of the panel than at a distal end of the panel.

8. The system of claim 1, wherein at least one surface of the light conducting panel is textured to distribute illumination more evenly over the rear of the display.

9. A computing device including:

a. a transflective display having a viewing surface and a rear surface;

b. a case enclosing the display such that the viewing surface of the display is exposed, and having a light transmitting input;

c. a light source, positioned externally from the case and removably affixed thereto, including at least one light emitting element for shining light into the light transmitting input; and

d. a light directing element comprising a light conducting panel disposed within the case for directing light emitted by the light emitting element through the rear surface of the display and out the viewing surface of the display, thereby illuminating the display.

10. A method for illuminating a transflective display in a display illuminating system for a computing device, wherein the display illuminating system comprises:

a. a case containing the transflective display and a light transmitting input;

b. at least one light emitting element, positioned externally from the case and removably affixed thereto, for emitting light into the light transmitting input; and

c. a light directing element comprising a light conducting panel disposed within the case and positioned with respect to the light transmitting input and the transflective display so as to receive light emitted by the light emitting element into the light transmitting input and directing such light through the transflective display, thereby illuminating the display,

wherein the display has a viewing surface, including the step of;

shining light from the light emitting element into the light transmitting input in the case, such that the light is directed through a rear surface of the display by the light directing element and exits through the viewing surface of the display.

11. A method for illuminating a transflective display of a computing device having a case having a transflective display having a viewing surface and a light transmitting input, at least one light emitting element, positioned externally from the case and removably affixed thereto, for emitting light into the light transmitting input, and a light directing element comprising a light conducting panel disposed within the case and positioned with respect to the light transmitting input and transflective display so as to receive light emitted by the light emitting element into the light transmitting input and direct such light through the transflective display, including the step of:

shining light from the light emitting element into the light transmitting input in the case, such that the light is directed through a rear surface of the display by the light directing element and exits through the viewing surface of the display.