Projection device and method for projection comprising optical free-form surfaces

Patent metadata

Field	Value
Publication number	US-10764545-B2
Application number	US-201815910823-A
Country	US
Kind code	B2
Filing date	Mar 2, 2018
Priority date	Sep 4, 2015
Publication date	Sep 1, 2020
Grant date	Sep 1, 2020

Abstract

What is shown is a projection device having at least one light source and an array of optical channels. Each channel includes a first refractive optical free-form surface and a second refractive optical free-form surface and projection optics. The first and second refractive optical free-form surfaces are arranged between the light source and the projection optics and cause Köhler illumination of the projection optics by an object light pattern, resulting in the image to be projected on an image surface of the projection optics, wherein images of the array of optical channels superimpose one another.

First claim

The invention claimed is:

1. A projection device comprising at least one light source and an array of optical channels, wherein each optical channel comprises:
a first and a second refractive optical free-form surface and projection optics;
wherein the first and second refractive optical free-form surfaces are arranged between the at least one light source and the projection optics, cause a light redistribution and a change in the angular distribution of light of the at least one light source, so as to obtain an object light pattern lying in an object plant of the projection optics, and cause a Köhler illumination of the projection surface of the projection device ( 2 ) via the projection optics by the object light pattern,
where in an image to be projected results on the projection surface of the projection device by a superimposition of light from the optical channels.

2. The projection device in accordance with claim 1 , comprising a transmission-modulating structure configured to spatially shape the object light pattern in order to generate the image to be projected in the image plane of the projection optics with sharper edges than compared to imaging with no transmission-modulating structures.

3. The projection device in accordance with claim 1 ,
wherein the second refractive optical free-form surface is, relative to a light propagation direction, arranged behind the refractive optical free-form surface ( 8 )
wherein the first refractive optical free-form surface is configured to perform a spatial light redistribution and/or control of the ray direction angles of light rays emitted by the light source; and/or
wherein the second refractive optical free-form surface is configured to direct light rays onto the projection optics in a convergent manner in accordance with Köhler illumination;
wherein the first and second refractive optical free-form surfaces influence each other.

4. The projection device in accordance with claim 1 , wherein the first and/or the second optically refractive free-form surface(s) is/are configured so that an irradiance of the light from the light source in a light-transparent region of the transmission-modulating structure, is higher than the irradiance on a light-intransparent region of the transmission-modulating structure.

5. The projection device in accordance with claim 1 , wherein the first and second optically refractive free-form surfaces are configured to generate, based on a real light pattern, a virtual object light pattern in the optical channel between the light source and the second refractive optical free-form surface, wherein the virtual object light pattern results from imaging of the image to be projected, and wherein the real light pattern forms after transmitting through the first and second refractive optical free-form surfaces.

6. The projection device in accordance with claim 1 ,
wherein the projection optics is configured to image the image to be projected onto a real or onto a virtual projection surface; or
wherein the projection optics of the array of optical channels are configured to superimpose the images to be projected on a real or on a virtual projection surface.

7. The projection device in accordance with claim 1 , wherein the individual channels of the array of optical channels are configured to superimpose images comprising the same subject on a real or virtual projection surface.

8. The projection device in accordance with claim 1 , wherein the individual channels or groups of channels of the array of optical channels are configured to generate mutually differing images on a real or virtual projection surface, wherein an overall image is generated on the real or virtual projection surface by means of at least partial superimposing of the differing images.

9. The projection device in accordance with claim 1 , wherein the projection optics comprises at least one further refractive optical free-form surface configured to correct an imaging error or a plurality of imaging errors in a projected image.

10. The projection device in accordance with claim 1 , wherein optical structures of all the channels of the array of optical channels are arranged on planar substrates and/or in planes.

11. The projection device in accordance with claim 1 , wherein the first and/or the second refractive optical free-form surface(s) and/or the projection optics of mutually adjacent optical channels are arranged on a common curved envelope each, wherein chief ray direction angles of the mutually adjacent optical channels are adapted in order to avoid projection artifacts and/or optically inactive regions and/or discontinuities between the array channels when superimposing the images.

12. The projection device in accordance with claim 1 , wherein the projection device comprises at least one further transmission-modulated structure which suppresses scattering and/or stray light.

13. The projection device in accordance with claim 1 , wherein the optical channels comprise hexagonal, rectangular, strip-like, distorted regular, irregular or stochastic tiling.

14. A method for performing a projection, comprising
Using a projection device according to claim 1 , so as to project obtain an image to be projected on a projection surface of the projection device.

15. The projection device in accordance with claim 1 ,
wherein the second refractive optical free-form surface is, relative to a light propagation direction, arranged behind the refractive optical free-form surface,
wherein the first refractive optical free-form surface is configured to achieve, apart from a light convergence, a light re-direction by compressing incident light in a first light re-direction areas to achieve a irradiation increase and widening the incident light in second first light re-direction areas to achieve a irradiation decrease so that the second refractive optical free-form surface receives and redirects beam directions which are changed due to the light re-direction and so that the at least one light source is imaged onto an input pupil of the projection optics in an aberrated manner.

16. The projection device in accordance with claim 1 ,
wherein the first refractive optical free-form surface is composed of ellipsoids and conics and the second refractive optical free-form surface is composed of Cartesian ovals which are placed at foci of the ellipsoids and conics, wherein the ellipsoids and conics are placed at foci of the Cartesian ovals.

17. The projection device in accordance with claim 1 , wherein the objection plane of the projection optics, in which the object light pattern is located, lies between the light source and the second refractive optical free-form surface.

18. A projection device comprising at least one light source and an array of optical channels, wherein each channel comprises:
a first and a second refractive optical free-form surface and projection optics;
wherein the first and second refractive optical free-form surfaces are arranged between the at least one light source and the projection optics and cause Köhler illumination of the projection optics by an object light pattern, resulting in an image to be projected by superimposing images of the optical channels of the array on an image surface of the projection optics, wherein the object light pattern is a light pattern to be imaged by the projection optics and comprises a light distribution;
wherein two channels or two groups of channels of the array of optical channels are configured to process differing wavelength ranges, wherein the first channel or the first gro

Assignees

• Fraunhofer Ges Forschung

Inventors

• Michaelis Dirk
• Schreiber Peter

Classifications

• F21W2103/60

  Projection of signs from lighting devices, e.g. symbols or information being projected onto the road · CPC title

• G02B27/18

  for optical projection, e.g. combination of mirror and condenser and objective {(photographic, cine and overhead projectors G03B21/00; photographic projection printing G03B27/32; photolithographic projectors G03F7/20; projection television H04N5/74; colour projection television H04N9/31)} · CPC title

• G02B3/0056

  arranged along two different directions in a plane, e.g. honeycomb arrangement of lenses (G02B3/0043 takes precedence; miniaturised objectives for electronic devices employing wafer level optics G02B13/0085) · CPC title

• G03B21/13 Primary

  Projectors for producing special effects at the edges of picture, e.g. blurring · CPC title

• F21W2121/00

  Use or application of lighting devices or systems for decorative purposes, not provided for in codes F21W2102/00 – F21W2107/00 · CPC title