Colour-tunable light source unit with phosphor element

• US 9,115,862 B2
• Filed: 08/24/2010
• Issued: 08/25/2015
• Est. Priority Date: 08/24/2010
• Status: Active Grant

• Current Assignee: Coretronic Corporation
• Original Assignee: OSRAM GmbH (Ams-Osram AG)
• Inventors: Morgenbrod, Nico, Rehn, Henning
• Primary Examiner(s): Hanley, Britt D
• Application Number:
  US13/818,390
• Publication Number:
  US 20130155648A1
• Time in Patent Office: 1,827 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: A61B 1/0638 providing two or more wavelengths
• CPC Class Codes: A61B 1/0653 with wavelength conversion
• CPC Class Codes: A61B 1/0669 at proximal end of an endoscope
• CPC Class Codes: F21V 13/08 the elements being filters or photoluminescent elements and reflectors
• CPC Class Codes: F21V 9/20 Dichroic filters, i.e. devices operating on the principle of wave interference to pass specific ranges of wavelengths while cancelling others
• CPC Class Codes: G02B 15/14 by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective
• CPC Class Codes: G02B 19/0028 refractive and reflective surfaces, e.g. non-imaging catadioptric systems
• CPC Class Codes: G02B 19/0047 for use with a light source G02B19/009, G02B19/0095 take precedence; details of lighting devices in general F21V; non-semiconductor lasers having optical devices external to the laser cavity H01S3/005
• CPC Class Codes: G02B 23/2469 using optical fibres
• CPC Class Codes: G02B 27/0944 Diffractive optical elements, e.g. gratings, holograms gratings per se G02B5/18; holograms used as optical elements per se G02B5/32
• CPC Class Codes: G02B 27/0955 Lenses lenses per se G02B3/00
• CPC Class Codes: G02B 5/001 Axicons, waxicons, reflaxicons
• CPC Class Codes: G02B 6/0008 the light being emitted at the end of the fibre

Abstract

The invention concerns a light source unit of tunable spectral properties, having a pump light source and a phosphor element for a conversion of pump light into converted light intended for illuminating a target, wherein the phosphor element has at least two phosphor element sections interacting differently with pump light, and wherein the light source unit further comprises a deflecting unit, such as a zoom lens or a variable diffraction grating, for deflecting the pump light so as to vary a distribution of pump light incident onto the phosphor element with respect to the different phosphor element sections, in order to vary spectral properties of the combined converted light beam emanating from the light source unit.

Claims

1. A light source unit comprising

a pump light source for an emission of pump light,

a phosphor element for a conversion of said pump light into converted light for further use, which phosphor element comprises at least two phosphor element sections interacting differently with said pump light and being suitably arranged for an irradiation in at least one of a simultaneous and a selective manner by said pump light, and

a deflecting unit for deflecting at least a part of said pump light for varying said irradiation by altering a distribution of said pump light incident on said phosphor element with respect to said phosphor element sections in order to vary spectral properties of said converted light,

wherein said deflecting unit comprises a lens system for deflecting at least a part of said pump light intended for incidence onto said phosphor element, wherein said lens system comprises an axicon lens for generating an annular profile shape in a beam of said deflected pump light.

2. The light source unit according to claim 1, wherein said pump light is incident in a main propagation direction onto said phosphor element, and said phosphor element sections are rotationally symmetric with respect to said main propagation direction in a plane perpendicular thereto.

3. The light source unit according to claim 1, wherein said deflecting unit comprises a variable diffraction grating for deflecting at least a part of said pump light intended for incidence onto said phosphor element.

4. The light source unit according to claim 1, wherein said lens system is a zoom lens system for varying a cross-sectional size of a beam of said deflected pump light.

5. The light source unit according to claim 1, wherein said lens system is transversally movable within a beam of said pump light for varying an angle of deflection of said deflected pump light with respect to a main direction of propagation of said pump light entering said deflecting unit.

6. The light source unit according to claim 1, wherein a light guide is provided between said deflecting unit and said phosphor element for transmitting at least a part of said deflected pump light to said phosphor element.

7. The light source unit according to claim 6, wherein a coupling lens system is provided between said deflecting unit and an entry face of said light guide for coupling at least a part of said deflected pump light to said light guide.

8. The light source unit according to claim 6, wherein a focusing lens system is provided between an exit face of said light guide and said phosphor element for focusing said transmitted pump light exiting said light guide towards said phosphor element.

9. The light source unit according to claim 1, wherein a collecting lens system is provided for collecting at least a part of said converted light emanating from said phosphor element, said collecting lens system providing an exit pupil for a beam of said converted light intended for further use.

10. The light source unit according to claim 1, wherein a mixing optical element is provided in a path of said converted light for mixing said converted light emanating from said at least two different phosphor element sections with respect to coordinates in a plane perpendicular to said path for obtaining a beam of said converted light having a uniform cross-sectional distribution of spectral properties at a target to be illuminated.

11. The light source unit according to claim 10, wherein said mixing optical element is arranged in said exit pupil of said collecting lens system.

12. The light source unit according to claim 9, wherein a mirror is provided in said exit pupil of said collecting lens system and at least a part of said pump light is coupled to said mirror for being directed to said phosphor element.

13. The light source unit according to claim 1, wherein a main direction of propagation of said pump light incident on said phosphor element and a main direction of propagation of said converted light at said phosphor element are approximately opposite to each other and said phosphor element is provided on a heat sink not being translucent for said pump light.

14. The light source unit according to claim 1, wherein a main direction of propagation of said pump light incident on said phosphor element and a main direction of propagation of said converted light at said phosphor element approximately coincide and a dichroic mirror is provided in a path of said pump light incident onto said phosphor element, for reflecting at least a part of said converted light emanating from said phosphor element in a direction opposite to either of said main propagation directions.

19. A method for varying spectral properties of light emanating from a light source unit comprising a pump light source for an emission of pump light, a phosphor element for a conversion of said pump light into converted light for further use, which phosphor element comprises at least two phosphor element sections interacting differently with said pump light and being suitably arranged for an irradiation in at least one of a simultaneous and a selective manner by said pump light, and a deflecting unit for deflecting at least a part of said pump light for varying said irradiation, also in combination with one of claims 2 to 14, the method comprising a step of adjusting said deflecting unit for altering a distribution of said pump light incident on said phosphor element with respect to said phosphor element sections for varying spectral properties of said converted light,

wherein said deflecting unit comprises a lens system for deflecting at least a part of said pump light intended for incidence onto said phosphor element,

wherein said lens system comprises an axicon lens for generating an annular profile shape in a beam of said deflected pump light.

20. The light source unit according to claim 1, said lens system further comprising a second axicon lens, wherein the bases of the axicon lens and the second axicon lens are facing each other such that the deflection angle of said pump light exiting the second axicon lens is zero with respect to the axicon axis at any of the displayed relative positions of the axicons.

15. A surgical illumination system for illuminating surgical operating field comprising:

a pump light source for an emission of pump light, a phosphor element for a conversion of said pump light into converted light for further use, which phosphor element comprises at least two phosphor element sections interacting differently with said pump light and being suitably arranged for an irradiation in at least one of a simultaneous and a selective manner by said pump light, and a deflecting unit for deflecting at least a part of said pump light for varying said irradiation by altering a distribution of said pump light incident on said phosphor element with respect to said phosphor element sections in order to vary spectral properties of said converted light,

wherein said deflecting unit comprises a lens system for deflecting at least a part of said pump light intended for incidence onto said phosphor element,

wherein said lens system comprises an axicon lens for generating an annular profile shape in a beam of said deflected pump light.

16. A moving head spotlight, comprising:

a pump light source for an emission of pump light, a phosphor element for a conversion of said pump light into converted light for further use, which phosphor element comprises at least two phosphor element sections interacting differently with said pump light and being suitably arranged for an irradiation in at least one of a simultaneous and a selective manner by said pump light, and a deflecting unit for deflecting at least a part of said pump light for varying said irradiation by altering a distribution of said pump light incident on said phosphor element with respect to said phosphor element sections in order to vary spectral properties of said converted light,

wherein said deflecting unit comprises a lens system for deflecting at least a part of said pump light intended for incidence onto said phosphor element,

wherein said lens system comprises an axicon lens for generating an annular profile shape in a beam of said deflected pump light.

17. A projection system, comprising:

a pump light source for an emission of pump light, a phosphor element for a conversion of said pump light into converted light for further use, which phosphor element comprises at least two phosphor element sections interacting differently with said pump light and being suitably arranged for an irradiation in at least one of a simultaneous and a selective manner by said pump light, and a deflecting unit for deflecting at least a part of said pump light for varying said irradiation by altering a distribution of said pump light incident on said phosphor element with respect to said phosphor element sections in order to vary spectral properties of said converted light,

wherein said deflecting unit comprises a lens system for deflecting at least a part of said pump light intended for incidence onto said phosphor element,

wherein said lens system comprises an axicon lens for generating an annular profile shape in a beam of said deflected pump light.

18. A fibre-optical illumination system, comprising:

a pump light source for an emission of pump light, a phosphor element for a conversion of said pump light into converted light for further use, which phosphor element comprises at least two phosphor element sections interacting differently with said pump light and being suitably arranged for an irradiation in at least one of a simultaneous and a selective manner by said pump light, and a deflecting unit for deflecting at least a part of said pump light for varying said irradiation by altering a distribution of said pump light incident on said phosphor element with respect to said phosphor element sections in order to vary spectral properties of said converted light,

wherein said deflecting unit comprises a lens system for deflecting at least a part of said pump light intended for incidence onto said phosphor element,

wherein said lens system comprises an axicon lens for generating an annular profile shape in a beam of said deflected pump light.