Illumination optical system and method of manufacturing illumination optical system

• US 8,702,258 B2
• Filed: 02/21/2012
• Issued: 04/22/2014
• Est. Priority Date: 02/22/2011
• Status: Expired due to Fees

• Current Assignee: Stanley Electric Company Limited
• Original Assignee: Stanley Electric Company Limited
• Inventors: Toko, Yasuo
• Primary Examiner(s): Truong, Bao Q
• Application Number:
  US13/400,914
• Publication Number:
  US 20120212933A1
• Time in Patent Office: 791 Days
• Field of Search: 362/84, 362/538, 362/259
• US Class Current: 362/84
• CPC Class Codes: F21K 9/64 using wavelength conversion means distinct or spaced from the light-generating element, e.g. a remote phosphor layer
• CPC Class Codes: F21S 41/14 characterised by the type of light source
• CPC Class Codes: F21S 41/141 Light emitting diodes [LED]
• CPC Class Codes: F21S 41/147 the main emission direction of the LED being angled to the optical axis of the illuminating device
• CPC Class Codes: F21S 41/16 Laser light sources
• CPC Class Codes: F21S 41/176 Light sources where the light is generated by photoluminescent material spaced from a primary light generating element
• CPC Class Codes: F21S 41/255 Lenses with a front view of circular or truncated circular outline
• CPC Class Codes: F21S 41/285 Refractors, transparent cover plates, light guides or filters not provided in groups F21S41/24-F21S41/28
• CPC Class Codes: F21S 41/40 characterised by screens, non-reflecting members, light-shielding members or fixed shades
• CPC Class Codes: F21V 5/002 using microoptical elements for redirecting or diffusing light
• CPC Class Codes: F21V 9/30 Elements containing photoluminescent material distinct from or spaced from the light source shades F21V1/17; globes, bowls or cover glasses F21V3/08, F21V3/12; refractors F21V5/10; reflectors F21V7/26, F21V7/30; elements with provision for controlling the spectral properties or intensity F21V9/40
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: F21Y 2115/30 Semiconductor lasers
• CPC Class Codes: G02B 19/0014 at least one surface having optical power
• 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 5/32 Holograms used as optical elements
• CPC Class Codes: G03H 1/06 using incoherent light
• CPC Class Codes: G03H 1/2202 Reconstruction geometries or arrangements
• CPC Class Codes: G03H 2001/0413 for recording transmission holograms
• CPC Class Codes: G03H 2001/0439 for recording Holographic Optical Element [HOE] HOE per se G02B5/32
• CPC Class Codes: G03H 2260/12 : Photopolymer

Abstract

A compact illumination optical system manufactured at reasonable cost can be provided. The illumination optical system can include: a light source for emitting a light beam; a hologram element for converting the light beam emitted from the light source to reproduced light having a predetermined shape of light distribution and a predetermined luminance distribution; a fluorescent plate containing a fluorescent material for emitting visible light by absorbing the reproduced light emitted from the hologram element and entering the fluorescent material; and a lens for projecting forward the visible light emitted from the fluorescent plate.

Claims

1. An illumination optical system, comprising:

a light source configured to emit a light beam;

a hologram element configured to convert the light beam emitted from the light source to reproduced light having a predetermined shape of light distribution and a predetermined luminance distribution;

a fluorescent plate including a fluorescent material configured to emit visible light by absorbing the reproduced light emitted from the hologram element and entering the fluorescent material; and

a lens configured to project the visible light emitted from the fluorescent plate forward.

2. The illumination optical system according to claim 1, wherein the light beam emitted from the light source has a center wavelength of 450 nm or shorter, and

the fluorescent material is configured to absorb light in a wavelength region ranging from ultraviolet light wavelength to blue light wavelength, and is configured to emit visible light.

3. The illumination optical system according to claim 1, wherein the fluorescent material is provided in accordance with a density distribution or a thickness distribution corresponding to the luminance distribution.

4. The illumination optical system according to claim 2, wherein the fluorescent material is provided in accordance with a density distribution or a thickness distribution corresponding to the luminance distribution.

5. The illumination optical system according to claim 1, wherein the hologram element is configured to form a shape of light distribution of the reproduced light and a luminance distribution of the reproduced light.

6. The illumination optical system according to claim 2, wherein the hologram element is configured to form a shape of light distribution of the reproduced light and a luminance distribution of the reproduced light.

7. The illumination optical system according to claim 3, wherein the hologram element is configured to form a shape of light distribution of the reproduced light and a luminance distribution of the reproduced light.

8. The illumination optical system according to claim 4, wherein the hologram element is configured to form a shape of light distribution of the reproduced light and a luminance distribution of the reproduced light.

11. The illumination optical system according to claim 1, wherein the fluorescent plate contains a fluorescent material configured to emit visible light by absorbing the reproduced light emitted from the hologram element.

12. The illumination optical system according to claim 1, wherein the halogen element has nano-level finishing.

13. The illumination optical system according to claim 1, wherein the light source is a laser diode.

14. The illumination optical system according to claim 1, wherein the light source is a light emitting diode.

15. The illumination optical system according to claim 1, wherein the light source is configured to project light evenly about and along a light emitting axis, and the light emitting axis intersects the hologram element at a predetermined angle θ

greater than zero and less than ninety degrees.

16. The illumination optical system according to claim 1, wherein the light source is configured to project light evenly about and along a light emitting axis, and the light emitting axis intersects the hologram element at a substantially ninety degree angle.

9. A method for manufacturing an illumination optical system, the illumination optical system including:

a light source configured to emit a light beam;

a hologram element configured to convert the light beam emitted from the light source to reproduced light having a predetermined shape of light distribution and a predetermined luminance distribution;

a fluorescent plate including a fluorescent material for emitting visible light by absorbing the reproduced light emitted from the hologram element and entering the fluorescent material; and

a lens configured to project the visible light emitted from the fluorescent plate forward, the method comprising;

photographing an interference to produce the hologram element.

10. A method for manufacturing an illumination optical system, the illumination optical system including:

a light source configured to emit a light beam;

a hologram element configured to convert the light beam emitted from the light source to reproduced light having a predetermined shape of light distribution and a predetermined luminance distribution;

a fluorescent plate including a fluorescent material for emitting visible light by absorbing the reproduced light emitted from the hologram element and entering the fluorescent material; and

a lens configured to project the visible light emitted from the fluorescent plate forward, the method comprising;

calculating a design for the hologram element and processing a material for the hologram element to produce the hologram element.