Light guide for a display or keyboard

• US 5,746,493 A
• Filed: 03/08/1996
• Issued: 05/05/1998
• Est. Priority Date: 03/08/1996
• Status: Expired due to Fees

• Current Assignee: Ericsson, Inc. (Telefonaktiebolaget LM Ericsson)
• Original Assignee: Ericsson, Inc. (Telefonaktiebolaget LM Ericsson)
• Inventors: Wictor, Mats, Jonsson, Anders
• Primary Examiner(s): Lazarus, Ira S.
• Assistant Examiner(s): SPARK, MATTHEW J
• Application Number:
  US08/610,602
• Time in Patent Office: 788 Days
• Field of Search: 362/31, 362/23, 362/24, 362/26, 362/27, 362/29, 362/86, 362/88, 362/800
• US Class Current: 362/602
• CPC Class Codes: G02B 6/0001 specially adapted for lighting devices or systems lighting or signalling on vehicles using light guides B60Q1/00; lighting devices for vehicle dashboards B60Q3/10; lighting devices for vehicle interior using light guides B60Q3/62; lighting devices mounted on the vehicle rear part using light guides F21S43/235; measuring arrangements having light conducting pointers G01D13/265; illumination of liquid crystal displays G02F1/1336; illuminated signs G09F13/00
• CPC Class Codes: G02B 6/002 by shaping at least a portion of the light guide, e.g. with collimating, focussing or diverging surfaces
• CPC Class Codes: G02B 6/0038 Linear indentations or grooves, e.g. arc-shaped grooves or meandering grooves, extending over the full length or width of the light guide
• CPC Class Codes: G09F 13/18 Edge-illuminated signs
• CPC Class Codes: H01H 13/70 having a plurality of operating members associated with different sets of contacts, e.g. keyboard mounting together a plurality of independent switches H02B
• CPC Class Codes: H01H 2219/044 Edge lighting of layer
• CPC Class Codes: H01H 2219/062 Light conductor

Abstract

A light guide for illuminating a display and/or keyboard device is formed from translucent material as a planar element having a peripheral edge. A plurality of arcuately shaped light coupling recesses are formed on one side to transmit light from light sources substantially uniformly into the light guide. A plurality of light reflecting recesses are formed in the peripheral edge to reflect light at the edge back into the light guide in a manner useful for illuminating the keys of the device.

Claims

1. A light guide for illuminating a display or keyboard, comprising a substantially translucent element having a substantially rectangular shape with end edges and side edges, and having an upper surface and a lower surface, a first portion of the light guide being a backing screen for a display and a second portion being a keyboard portion having a plurality of keyholes, the light guide having a plurality of light coupling recesses formed on a first end edge adjacent to the first portion, the recesses being arcuately shaped to transmit light substantially uniformly into the light guide.

2. The light guide as claimed in claim 1, wherein the light coupling recesses are semi-circularly shaped.

3. The light guide as claimed in claim 1, wherein the top and bottom surfaces are formed as reflectively smooth surfaces to reflect light in the light guide back into the light guide.

4. The light guide as claimed in claim 1, further having a plurality of reflective recesses formed on the side edges, wherein a portion of light transmitted to the peripheral edge is reflected by the reflective recesses back into the light guide.

5. The light guide as claimed in claim 4, wherein additional light reflecting recesses are formed on a second end edge adjacent the keyhole portion.

6. The light guide as claimed in claim 4, wherein the light reflecting recesses are each positioned in alignment with a space between adjacent key holes.

7. The light guide as claimed in claim 4, wherein the reflective recesses are V-shaped.

8. The light guide as claimed in claim 7, wherein the reflective recesses are arcuately shaped.

9. The light guide as claimed in claim 1, wherein the key holes have a frustoconical shape and are wider at the bottom surface than at the top surface.

10. The light guide as claims in claim 1, wherein the keyholes are arranged in rows, and further comprising a plurality of light source holes in the second portion between the rows of keyholes.

11. A light guide for illuminating a display and keyboard, comprising a substantially translucent element having an upper surface, a lower surface, and end and side peripheral edges, a first portion of the light guide adjacent to a first end edge comprising a backing screen for a display, and a second portion of the light guide having a plurality of holes for keys, the light guide having a plurality of light coupling recesses formed on a first of the end edges, the light coupling recesses being arcuately shaped to transmit light substantially uniformly into the light guide, and a plurality of light reflecting recesses positioned on the opposite end edge and the side edges.

12. The light guide as claimed in claim 11, wherein the light reflecting recesses are V-shaped.

13. The light guide as claimed in claim 11, wherein the light coupling recesses are semi-circularly shaped.

14. The light guide as claimed in claim 11, wherein the light reflecting recesses are each positioned in alignment with a space between adjacent key holes.

15. The light guide as claimed in claim 11, wherein the top and bottom surfaces are formed as reflectively smooth surfaces to reflect light in the light guide back into the light guide.

16. The light guide as claimed in claim 11, wherein the key holes have a frustoconical shape and are wider at the bottom surface than at the top surface.

17. The light guide as claims in claim 12, wherein the holes for keys are arranged in rows, and further comprising a plurality of light source holes in the second portion between the rows of holes.