Method and apparatus for distributing light to the user interface of an electronic device

• US 6,598,987 B1
• Filed: 06/15/2000
• Issued: 07/29/2003
• Est. Priority Date: 06/15/2000
• Status: Expired due to Term

• Current Assignee: Nokia Technologies Oy (Nokia Corporation)
• Original Assignee: Nokia Mobile Phones UK Limited (Nokia Corporation)
• Inventors: Parikka, Marko
• Primary Examiner(s): O'Shea, Sandra
• Assistant Examiner(s): DELGIZZI, RONALD ERNEST
• Application Number:
  US09/594,872
• Time in Patent Office: 1,139 Days
• Field of Search: 362/26, 362/24, 362/85, 362/29, 362/30, 362/330, 362/31, 385/10, 385/901
• US Class Current: 362/26
• CPC Class Codes: G01D 11/28 Structurally-combined illuminating devices
• CPC Class Codes: G02B 6/0016 Grooves, prisms, gratings, scattering particles or rough 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: 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: H01H 2219/06 Reflector
• CPC Class Codes: H01H 2219/062 Light conductor
• CPC Class Codes: H04M 1/22 Illumination; Arrangements for improving the visibility of characters on dials
• CPC Class Codes: H04M 1/724 User interfaces specially adapted for cordless or mobile telephones
• CPC Class Codes: Y10S 385/901 Illuminating or display apparatus

Abstract

A system and method is described for distributing light within a light guide which is used for illuminating the user interface of an electronic device. The light guide is formed as a thin film and impressed with a pattern of input and output diffraction gratings to control the transmission of light into and out of the light guide to efficiently illuminate the user interface.

Claims

1. In an electronic device having a circuit board with first and second sides, operating components connected to said first side of said circuit board, and a user interface assembled on said second side, a system for illuminating the user interface comprising:

a source of light operatively connected to the circuit board on said first side, said light source aligned with an opening constructed in said circuit board which allows said light to be transmitted from said first side to said second side;

a light guide assembled between said user interface and said second side to receive light transmitted by said light source; and

an input diffraction optical element positioned within said light guide to diffract the light transmitted into the light guide to distribute said light within the light guide.

2. In an electronic device having a circuit board with first and second sides, operating components connected to said first side of said circuit board, and a user interface assembled on said second side, a system for illuminating the user interface, according to claim 1 wherein said diffraction optical unit is a diffraction grating having a pattern which causes a different angle of diffraction for different angles of incidence of said light source.

3. In an electronic device having a circuit board with first and second sides, operating components connected to said first side of said circuit board, and a user interface assembled on said second side, a system for illuminating the user interface, according to claim 1 wherein said user interface has spaced components to be illuminated, wherein said system further comprises at least one output diffraction optical element associated with said light guide to diffract light within the light guide out of the light guide in spatial relation to said spaced components.

4. In an electronic device having a circuit board with first and second sides, operating components connected to said first side of said circuit board, and a user interface assembled on said second side, a system for illuminating the user interface, according to claim 3 wherein said at least one output diffraction optical element further comprises multiple diffraction gratings operatively associated with certain of said spaced components.

5. In an electronic device having a circuit board with first and second sides, operating components connected to said first side of said circuit board, and a user interface assembled on said second side, a system for illuminating the user interface, according to claim 1, wherein said light source includes an array of light emitting diodes aligned with associated openings in said circuit board to transmit light to predetermined portions of said light guide and wherein said system further includes an input diffraction grating operatively associated with said light guide to receive light from each of the light emitting diodes of said array and diffract the light transmitted into the light guide at an angle optimized to maximize the portion of light distributed within the light guide.

6. In an electronic device having a circuit board with first and second sides, operating components connected to said first side of said circuit board, and a user interface assembled on said second side, a system for illuminating the user interface, according to claim 3, wherein the spaced components include a keyboard and a liquid crystal display panel.

7. A light guide for distributing light within an electronic device for illuminating the user interface thereof comprising:

a light guiding panel to receive light from a light source at a predetermined location on said panel; and

an input diffraction optical element positioned within said light guide to diffract the light transmitted into the light guide to distribute said light within the light guide.

8. A light guide for distributing light within an electronic device for illuminating the user interface, according to claim 7, wherein the input diffraction optical element is a diffraction grating.

9. A light guide for distributing light within an electronic device for illuminating the user interface thereof, according to claim 7, further comprising an output diffraction optical element operatively associated with said light guide to diffract light within the light guide out of the light guide to illuminate a predetermined portion of said user interface.

10. A light guide for distributing light within an electronic device for illuminating the user interface, according to claim 9, wherein the output diffraction optical element is a diffraction grating.

11. A light guide for distributing light within an electronic device for illuminating the user interface thereof, according to claim 7, wherein the light guide is constructed in the form of a thin film.

12. A light guide for distributing light within an electronic device for illuminating the user interface thereof, according to claim 11, wherein the input diffraction optical element comprises an array of input diffraction gratings aligned with multiple light sources impressed on the light guide in a predetermined pattern.

13. A light guide for distributing light within an electronic device for illuminating the user interface thereof, according to claim 12, further comprising an array of output diffraction optical elements operatively associated with said light guide to diffract light within the light guide out of the light guide to illuminate a predetermined portion of said user interface, said array of output diffraction gratings impressed on the light guide in a predetermined pattern.

14. A light guide for distributing light within an electronic device for illuminating the user interface, according to claim 13, wherein the output diffraction optical elements are diffraction gratings.

15. In an electronic device having a circuit board with first and second sides, operating components connected to said first side of said circuit board, and a user interface assembled on said second side, a method for illuminating the user interface thereof comprising the steps of:

constructing openings in the circuit board extending from said first side through said second side to allow the transmission of light;

connecting an array of light emitting diodes on the first side of said circuit board to transmit light through said openings;

positioning a light guide on the second side of said circuit board to receive light transmitted through the openings; and

constructing a series of input diffraction optical elements positioned within said light guide to diffract the light transmitted into the light guide to distribute said light within the light guide.

16. A light guide for distributing light within an electronic device for illuminating the user interface, according to claim 15, wherein the input diffraction optical elements are diffraction gratings.

17. In an electronic device having a circuit board with first and second sides, operating components connected to said first side of said circuit board, and a user interface assembled on said second side, a method for illuminating the user interface thereof, according to claim 15, wherein the user interface has spaced components to be illuminated, further comprising the step of constructing at least one output diffraction optical element associated with said light guide to diffract light within the light guide out of the light guide in spatial relation to said spaced components.

18. A light guide for distributing light within an electronic device for illuminating the user interface, according to claim 17, wherein the output diffraction optical element is a diffraction grating.

19. In an electronic device having a circuit board with first and second sides, operating components connected to said first side of said circuit board, and a user interface assembled on said second side, a method for illuminating the user interface thereof, according to claim 15, wherein said input and output diffraction optical elements are constructed as a unit to form a pattern and said pattern is impressed on said light guide during the construction of said light guide.

20. A method of constructing a light guide for distributing light within an electronic device for illuminating the user interface thereof comprising the steps of:

constructing a light guiding panel in the form of a thin film to receive light from a light source at a predetermined location on said panel;

designing a pattern of input diffraction gratings for operative association with said light guide to diffract the light transmitted into the light guide at an angle optimized to maximize the dispersion of light within the light guide;

designing a pattern of output diffraction gratings for association with said light guide to diffract light within the light guide out of the light guide in spatial relation to said user interface; and

generating a form representing said combined input and output diffraction grating patterns; and

impressing said combined pattern into said light guide during the construction thereof.