Compact light mixing and diffusing apparatus

• US 6,238,076 B1
• Filed: 03/29/1999
• Issued: 05/29/2001
• Est. Priority Date: 03/29/1999
• Status: Expired due to Term

• Current Assignee: Celestica Incorporated, Primetech Electronics, Inc. (Celestica Incorporated)
• Original Assignee: Primetech Electronics, Inc. (Celestica Incorporated)
• Inventors: Vandelac, Jean-Pierre, Pascale, Danny
• Primary Examiner(s): Husar, Stephen
• Assistant Examiner(s): WARD, JOHN A
• Application Number:
  US09/280,102
• Time in Patent Office: 792 Days
• Field of Search: 362/555, 362/558, 362/560, 362/31, 362/276, 362/26, 340/814.45, 340/814.75
• US Class Current: 362/558
• CPC Class Codes: G02B 5/021 the diffusion taking place at the element's surface, e.g. by means of surface roughening or microprismatic structures
• CPC Class Codes: H02J 7/0048 Detection of remaining charge capacity or state of charge [SOC]

Abstract

The present system provides a compact light diffusing and mixing structure for uniformly dispersing light at an exit surface, the apparatus having a light entrance surface which faces a light exit surface located on the opposite side of the light diffusing and mixing structure; a beam splitter light guide assembly located between the entrance and exit surface; a reflective surface located adjacent to the beam splitter light guide assembly. The light diffusing structure works such that light entering the entrance surface on striking the beam splitter light guide assembly is directed in part directly towards the exit surface and in part towards the reflective surface which in turn directs the light towards the exit surface and thereby evenly diffusing or dispersing the light across the exit surface. The system also provides a compact fast battery charger for Ni-MH and NiCAD batteries. The charger can indicate the degree of charge of the battery during a charging state and a discharging state.

Claims

1. A compact light diffusing and mixing structure for uniformly dispersing at an exit surface light from a light source, said light diffusing structure comprising:

a light entrance surface and a light exit surface located on the light diffusing and mixing structure;

a light dispersing assembly in the light diffusing and mixing structure between the entrance and exit surfaces, which breaks up light into a plurality of sub-beams having different directions;

a light spreading reflective surface located in the light diffusing and mixing structure adjacent to the light dispersing assembly;

the light diffusing structure works such that light from the light source on entering the entrance surface strikes the light dispersing assembly and a first portion is guided directly towards the exit surface and a second portion is guided towards the light spreading reflective surface which in turn spreads the light towards the exit surface and thereby evenly spreads the light across the exit surface; and

wherein a proportion of light in said sub-beams is substantially independent of a precise alignment of the light source with respect to the entrance surface, and the exit surface is substantially larger than the entrance surface.

2. The structure of claim 1 wherein the light dispersing assembly comprises a light diverter and an adjacent light guide wherein the light diverter and the light spreading reflective surface are mutually configured such that the first portion of the light which the light diverter directs towards the light spreading reflective surface is reflected towards the exit surface in a first predetermined pattern and second portion of the light which is directed directly towards the exit surface by the light guide in a second predetermined pattern.

3. The structure of claim 1 wherein the entrance surface has a light diffusing texture.

4. The structure of claim 1 wherein the exit surface has a light diffusing texture.

5. The structure of claim 1 wherein a light source is positioned so it illuminates the entire entrance surface.

6. The structure of claim 1 wherein a light source is at least one light emitting diode.

7. The structure of claim 6 wherein the at least one light emitting diode comprises two light emitting diodes of different colors whereby varying the intensity of the diodes changes the color of light at the exit surface.

8. The structure of claim 6 wherein the at least one light emitting diode can be positioned at between 0.5 to 1.5 mm from the entrance surface.

9. The structure of claim 1 wherein the structure is made of a light transmissive solid body and wherein said light dispersing assembly and said spreading reflective surface utilize TIR.

10. The structure of claim 9 wherein the light dispersing assembly further comprises a second beam diverter situated such that the light guide is sandwiched between the first and second beam diverter and wherein the second beam diverter has a second light spreading reflective surface adjacent to it and the second beam diverter and the second light spreading reflective surface are mutually configured such that a third portion of the light that the second beam diverter directs towards the second reflective surface is reflected towards the exit surface in a third predetermined pattern, whereby the first, second and third predefined patterns together evenly diffuse the light across the exit surface.

11. The structure of claim 10 wherein the light dispersing assembly is positioned adjacent to the entrance surface and wherein the first and second light diverters are triangular hollow cavities in the light diffusing and mixing structure each of which has an active surface, the active surface being a flat plane positioned at an angle of 45 degrees to a plane of the entrance surface, but the active planes of the first and second diverter are in mutually opposite orientations so that they divert the first and third portions of the light at 180 degrees away from each other towards their adjacent light spreading reflective surfaces which light spreading reflective surfaces are curved surfaces and the light guide sandwiched there between is a flattened thin plate structure.

12. The structure of claim 11 wherein the light source is at least two light sources of different color and whereby varying the intensity of each of the at least two light sources produces a uniformly intense single hue of a selected color at the exit surface.

13. The structure of claim 1 wherein the light spreading reflective surface collimates the first portion and directs it at an angle towards the exit surface so that it spreads the first portion out over the exit surface.

14. The structure of claim 1 wherein the exit surface is three to six times the size of the entrance surface.

15. A method for mixing and diffusing light in a small area to provide uniform illumination on a visual display, said method comprising the steps of:

generating at least one light beam;

breaking the at least one beam of light into a plurality of sub-beams having different directions and proportions of light substantially independent of a position of said at least one light beam within a predefined area;

diffusing the plurality of sub-beams in a predefined pattern so that the cross sectional area of each of the plurality of beams increases to a predetermined size;

projecting the plurality of sub-beams onto a visual display surface in an additively uniform pattern; and

whereby the sub-beams of light striking the visual display present a uniformly intense dispersion of light across the visual display and the area of a plane of the visual display is substantially larger than a cross sectional area of the at least one beam of light generated.

16. The method of claim 15 wherein the step of generating the at least one beam of light further comprises the steps of:

generating at least two beams of light, each beam being of a different color;

varying the intensities of each beam in a predetermined format so that a predesignated color of uniform hue and intensity appears on the visual display.

17. The method of claim 16 wherein the step of generating at least one beam comprises generating two beams of the same color light and wherein any variation in the intensity of either beam does not affect the uniformity or intensity of the light as it appears on the visual display.

18. An indicator device which comprises:

at least two light sources of different colors;

a light pipe with a light exit surface and an entrance surface of the light pipe receiving light from said at least two light sources, said pipe mixing light from said sources, said light exit surface being positioned for viewing by a user of an electronic apparatus; and

circuitry operatively connected to a single variable signal representing a state of the apparatus, said circuit in turn is operatively connected to the light sources which light sources are each responsive to an intensity control signal generated by the circuit in response to the single variable signal indicative of the state, such that the light sources produce at the exit surface of the light pipe a unique color visual indication of the state.

19. The device of claim 18 wherein the single variable signal is indicative of a state of charge of a battery which powers the electronic apparatus.

20. The device of claim 19 wherein the state of charge of the battery of which the signal is indicative is the state of charge of the battery during a charging of the battery.

21. The device of claim 20 wherein the at least two light sources are a first LED and a second LED, and the variable signals generated by the circuit in response to the single variable signal are a first signal which causes the first LED to lose intensity during the charging of the battery and turn OFF when the battery is filly charged, and a second signal which causes the second LED to turn ON and increase in intensity during the charging of the battery, whereby the hue of light created at the exit surface by the mixing of the light from the LEDs by the light pipe is indicative of the charge of the battery.

22. The device of claim 19 wherein the state of charge of the battery of which the signal is indicative is the state of charge of the battery during a discharging of the battery.

23. The device of claim 22 wherein the at least two light sources are a first LED and a second LED, and the variable signals generated by the circuit in response to the single variable signal are a second signal which causes the second LED to lose intensity during the discharging of the battery and turn OFF when the battery is fully discharged, and a first signal which causes the first LED to turn ON and increase in intensity during the during the discharging of the battery, whereby the hue of light created at the exit surface by the mixing of the light from the LEDs by the light pipe is indicative of the charge of the battery.