Method of designing optical systems and corresponding optical system

• US 8,694,287 B2
• Filed: 10/07/2009
• Issued: 04/08/2014
• Est. Priority Date: 10/16/2008
• Status: Expired due to Fees

• Current Assignee: OSRAM GmbH (Ams-Osram AG), Osram Opto Semiconductors GmbH (Ams-Osram AG)
• Original Assignee: OSRAM GmbH (Ams-Osram AG)
• Inventors: Capeleto, Simone, Schroll, Katrin, Schwalenberg, Simon, Streppel, Ulrich
• Primary Examiner(s): Shah, Kamini S
• Assistant Examiner(s): Johnson, Cedric D
• Application Number:
  US13/124,737
• Publication Number:
  US 20110208489A1
• Time in Patent Office: 1,644 Days
• Field of Search: 703/1, 703/5, 351/177
• US Class Current: 703/1
• CPC Class Codes: F21V 3/00 Globes; Bowls; Cover glasses with refracting properties F21V5/00; with reflecting properties F21V7/00; characterised by cooling arrangements F21V29/506
• CPC Class Codes: F21V 5/00 Refractors for light sources characterised by cooling arrangements F21V29/504
• CPC Class Codes: F21V 7/00 Reflectors for light sources characterised by cooling arrangements F21V29/505
• CPC Class Codes: F21V 9/00 Elements for modifying spectral properties, polarisation or intensity of the light emitted, e.g. filters coloured shades F21V1/00; elements characterised by cooling arrangements F21V29/502
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]

Abstract

An optical system including at least one light source, such as a LED source (10), and an optics (30) subjected to aging as a result of exposure to the light source (10) is designed by: defining an aging model for the optics (30), defining a thermal model for the light source (10, 100) as a spatial function representative of the temperature generated by the light source (10, 100), and defining the distance of the optics (30) from the light source (10) as a function of the aging model and the thermal model. The optical overall system (single or multiple reflector and lens) is finally optimised starting from the results achieved in the previous steps.

Claims

1. A method of making an optical system including at least one light source and an optics subjected to aging as a result of exposure to said at least one light source, wherein the method comprises the steps of:

defining, using a computing system, an aging model for said optics;

defining, using the computing system, a thermal model for said at least one light source, wherein said thermal model is a spatial function representative of a temperature generated by said at least one light source;

defining a distance of said optics from said at least one light source as a function of said aging model and said thermal model to ensure a given lifetime for said optics, wherein said aging model defines a threshold temperature not to be exceeded by a material of said optics to ensure a given lifetime for said optics; and

positioning said at least one light source away from said optics at least the defined distance and so that light from said at least one light source passes through said optics.

2. The method of claim 1, wherein said optics is a plastics optics.

3. The method of claim 1, further comprising the step of selecting said distance of said optics from said at least one light source as a minimum distance ensuring that the temperature of said optics as exposed to said at least one light source does not exceed said threshold temperature.

4. The method of claim 1, wherein said thermal model is representative of the temperature generated by said at least one light source as a function of the distance therefrom.

5. The method of claim 1, wherein said optical system includes a plurality of light modules, the method comprising the step of arranging said light modules according to a circular-symmetrical arrangement, wherein said plurality of light modules have a mutual distance therebetween.

6. The method of claim 5, further comprising the step of arranging said plurality of light modules at a minimum allowable distance therebetween.

7. The method of claim 5, further comprising the steps of:

defining a maximum space available for arranging said plurality of light modules, and

arranging said plurality of light modules at a maximum distance admitted by maximum space available.

8. The method of claim 1, comprising, once said distance of said optics from said at least one light source is defined, the steps of:

partitioning a solid angle of light emission from said at least one light source in an internal zone and in an external zone, wherein light rays in said internal zone are directed to said optics to be shaped thereby, and

providing at least one reflector to collect light rays in said external zone and direct them in the same direction of said light rays as shaped by said optics.

9. The method of claim 8, wherein said system includes a plurality of light sources, the method further comprising the step of providing said at least one reflector in the form of a multi-polar reflector.

10. The method of claim 1, wherein said optical system includes a plurality of light modules, the method further comprising the step of providing said optics in the form of a multiple, single-piece optics.

11. The method of claim 1, further comprising the steps of selecting a LED as said at least one light source.

12. An optical system designed according to the method of claim 1, the system also comprising a cover for the system, wherein said cover and said optics are integrated to a single piece.

13. The method of claim 1, wherein said optical system includes a plurality of light modules, the method further comprising the step of providing said optics in the form of a multiple, single-piece optics, with a pillow-like structure.