Light guiding plate with internal micro-prisms

• US 6,575,584 B1
• Filed: 04/14/2000
• Issued: 06/10/2003
• Est. Priority Date: 05/28/1999
• Status: Expired due to Fees

• Current Assignee: Université de Liège
• Original Assignee: Université de Liège
• Inventors: Habraken, Serge
• Primary Examiner(s): CARIASO, ALAN B
• Application Number:
  US09/550,050
• Time in Patent Office: 1,152 Days
• Field of Search: 362/31, 362/327, 362/330, 362/339, 362/346, 362/259, 362/551, 362/553, 362/561, 349/62, 349/65
• US Class Current: 362/609
• CPC Class Codes: G02B 6/0028 Light guide, e.g. taper
• CPC Class Codes: G02B 6/0033 Means for improving the coupling-out of light from the light guide

Abstract

An illumination device comprising a plate provided for guiding light there through, having an input for receiving an input light beam to be injected into said plate and an array of N micro-prisms for receiving the input light beam and producing an output light beam from the input light beam. The array of micro-prisms is located inside the plate.

Claims

1. An illumination device comprising a plate for guiding light there through, said plate having an input for receiving an input light beam injected into said plate and an array of N micro-prisms inside and encapsulated by said plate, each said array of N micro-prisms having an inclined reflective surface forming a homogenous medium around said array of N micro-prisms for receiving the input light beam and for producing an output light beam from said input light beam, the micro-prisms have a right angle triangle cross section and an angle between inclined and vertical surfaces between 15 to 35 degrees, and the array of micro-prisms receives the input light beam with an angle of incidence less than 90 degrees.

2. The illumination device according to claim 1, wherein the input light beam is injected into the plate through one edge.

3. The illumination device according to claim 1, wherein the input light beam is partly reflected by the device onto the array of N micro-prisms.

4. The illumination device according to claim 1, wherein the input light beam is partly transmitted through N−

1 micro-prisms.

5. The illumination device according to claim 1, wherein the distance between two successive micro-prisms is inferior to 1 mm.

6. The illumination device according to claim 1, wherein the device cooperates with a light source for providing the input light beam.

7. The illumination device of claim 6, wherein the light source is an optical fibre, a tube lamp, a light bulb, or a light emitting diode.

8. The illumination device according to claim 7, further comprises a fan-out generator in cooperation with a light source having low divergence and small section for providing the input light beam.

9. The illumination device of claim 8, wherein the light source having low divergence and small section is an optical fibre with a collimating lens, a laser diode with a collimating lens, or a gas laser beam.

10. An illumination device comprising a plate for guiding light there through, said plate having an input for receiving an input light beam injected into said plate and an array of N micro-prisms inside and encapsulated by said plate, each said array of N micro-prisms having an inclined reflective surface forming a homogenous medium around said array of N micro-prisms for receiving the input light beam and for producing an output light beam from said input light beam, the micro-prisms have a right angle triangle cross section and an angle between inclined and vertical surfaces between 40 to 50 degrees, and the array of micro-prisms receiving the input light beam with an angle of incidence between 40 to 50 degrees.

11. An illumination device comprising a plate for guiding light there through, said plate having an input for receiving an input light beam injected into said plate and an array of N micro-prisms inside and encapsulated by said plate, each said array of N micro-prisms having an inclined reflective surface forming a homogenous medium around said array of N micro-prisms for receiving the input light beam and for producing an output light beam from said input light beam, the micro-prisms have a right angle triangle cross section and an angle between inclined and vertical surfaces between 40 to 50 degrees, and the array of N micro-prisms is in cross incidence with another array of N micro-prisms in the plate.

12. A process to manufacture an illumination device, the illumination device comprising a plate provided for guiding light there through, having an input for receiving an input light beam to be injected into said plate and an array of N micro-prisms provided for receiving the input light beam and producing an output light beam from said input light beam wherein the array of micro-prisms are located inside the plate, and said process comprises:

a) etching and polishing a master mould into a micro-prisms master structure,

b) copying the master into a copy with a micro-prisms structure,

c) depositing a reflective coating on the micro-prisms structure of the copy, and

d) casting the resulting reflective micro-prisms structure.

13. The process according to claim 12, wherein the casting of the reflective micro-prisms is replaced by a superimposition of a second negative copy on the reflective micro-prisms structure, followed by a sealing with an optical cement or adhesive.