# US 8,139,909 B2 · Illuminator method and device

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- Number: US 8,139,909 B2
- Document ID: US8139909B2
- Status: Granted
- Kind: B2
- Application number: 12/800,551
- Filed: 2010-05-17
- Published: 2010-09-16
- Granted: 2012-03-20
- Earliest claimed: 2006-08-10
- Assignees: Upstream Engineering Oy
- Inventors: Ilkka A. Alasaarela; Jussi P. Soukkamäki; Teuvo K. Viljamaa
- Web page: https://patentgrep.com/patent/US8139909B2

## CPC

- F21V 5/046: {the lens having a rotationally symmetrical shape about an axis for transmitting light in a direction mainly perpendicular to this axis, e.g. ring or annular lens with light source disposed inside the ring}
- G02B 19/0028: {refractive and reflective surfaces, e.g. non-imaging catadioptric systems}
- G02B 19/0061: {the light source comprising a LED}
- F21V 7/0091: {using total internal reflection}
- F21V 13/04: the elements being reflectors and refractors {(for vehicle rear lights F21S43/40)}
- F21Y 2115/10: Light-emitting diodes [LED]
- G02B 21/06: Means for illuminating specimens
- F21V: FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- F21Y: INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO THE FORM OR THE KIND OF THE LIGHT SOURCES OR OF THE COLOUR OF THE LIGHT EMITTED

## Abstract

A first toroidal ray guide defines an axis of revolution and has a toroidal entrance pupil adapted to image light incident on the entrance pupil at an angle to the axis of revolution between 40 and 140 degrees, and it also has a first imaging surface opposite the entrance pupil. A second toroidal ray guide also defines the same axis of revolution and has a second imaging surface adjacent to the first imaging surface. Various additions and further qualities of the ray guides, which form optical channels, are disclosed. In a method light emanating from a source at between 40-140 degrees from an optical axis is received at an entrance pupil of a ray guide arrangement that is circularly symmetric about the optical axis. Then the received light is redirected through the ray guide arrangement to an exit pupil in an average direction substantially parallel to the optical axis.

## Claims

### Claim 1

An apparatus comprising:
a first toroidal ray guide defining an axis of revolution and having a toroidal entrance pupil adapted to image radiation from a non-point source that is incident on the entrance pupil at an angle to the axis of revolution between 40 and 140 degrees, said first toroidal ray guide having a first imaging surface opposite the entrance pupil; and
a second ray guide also defining the axis of revolution and having a second imaging surface adjacent to the first imaging surface and an exit pupil opposite the second imaging surface,
wherein the first and second ray guides are arranged to substantially image the entrance pupil to the exit pupil.

### Claim 2 (depends on 1)

The apparatus of claim 1, wherein the angle is between 45 and 135 degrees.

### Claim 3 (depends on 1)

The apparatus of claim 1, wherein a surface of the first toroidal ray guide outboard from the axis of revolution comprises a reflective surface.

### Claim 4 (depends on 1)

The apparatus of claim 1, wherein the said toroidal entrance pupil comprises a first entrance pupil and wherein the first imaging surface is adjacent to a first portion of the second imaging surface, the apparatus further comprising:
a third toroidal ray guide also defining the axis of revolution and having a toroidal second entrance pupil adapted to image radiation from the non-point source that is incident on the second entrance pupil at an angle to the axis of revolution between 40 and 140 degrees, said third toroidal ray guide having a third imaging surface opposite the second entrance pupil, and wherein the third toroidal ray guide is disposed inboard the first toroidal ray guide.

### Claim 5 (depends on 4)

The apparatus of claim 4, further comprising the non-point source that comprises a light source disposed along the axis of revolution such that light emanating directly from the source is incident on the entrance pupil at an angle to the axis of revolution between 40 and 140 degrees, and the axis of revolution comprises a system optical axis of the apparatus.

### Claim 6 (depends on 5)

The apparatus of claim 5, wherein:
the first entrance pupil is adapted to guide substantially all light incident upon it from the light source through the first toroidal ray guide and to the first imaging surface; and
the second entrance pupil is adapted to guide substantially all light incident upon it from the light source through the third toroidal ray guide and to the third imaging surface, and wherein the first and second ray guides are arranged such that in any radial plane, the first entrance pupil images the incident radiation to an intermediate image substantially between the first and second imaging surfaces, and together the first and second imaging surfaces image the entrance pupil to the exit pupil.

### Claim 7 (depends on 1)

The apparatus of claim 1, wherein the first toroidal ray guide and the second ray guide are each made of an optical material having a refractive index between about 1.3 and about 1.7.

### Claim 8 (depends on 7)

The apparatus of claim 7, wherein the optical material is selected from the group consisting of cyclic olefin copolymer, polymethyl methacrylate, polycarbonate, and polystyrene.

### Claim 9 (depends on 1)

The apparatus of claim 1, further comprising the non-point source that comprises a light source disposed along the axis of revolution such that light emanating directly from the source is incident on the entrance pupil at an angle to the axis of revolution between 40 and 140 degrees, wherein the axis of revolution comprises a system optical axis of the apparatus.

### Claim 10 (depends on 9)

The apparatus of claim 9, wherein the light source is disposed within a substantially hemispherical dome that faces the entrance pupil.

### Claim 11 (depends on 10)

The apparatus of claim 10, wherein the entrance pupil comprises a fourth imaging surface.

### Claim 12 (depends on 11)

The apparatus of claim 11, wherein the fourth imaging surface is adapted to form an intermediate image from the light source at a plane perpendicular to the system optical axis and adjacent to the first imaging surface.

### Claim 13 (depends on 1)

The apparatus of claim 1, wherein the first and second ray guides are arranged to substantially image in each radial plane the incident radiation to an intermediate image and the intermediate image to an image and the entrance pupil to the exit pupil.

### Claim 14 (depends on 9)

The apparatus of claim 9, wherein the first toroidal ray guide is adapted so as to redirect substantially all light incident at the entrance pupil from the light source to the first imaging surface.

### Claim 15 (depends on 9)

The apparatus of claim 9, wherein the first toroidal ray guide and the second ray guide are adapted so as to convert substantially uniform circular illumination from the light source to substantially uniform rectilinear illumination from the exit pupil.

### Claim 16 (depends on 1)

The apparatus of claim 1, further comprising a Fresnel lens centered on the axis of revolution.

### Claim 17 (depends on 16)

The apparatus of claim 16, wherein outboard portions of the Fresnel lens lie adjacent to the second imaging surface.

### Claim 18 (depends on 1)

The apparatus of claim 1, wherein the second ray guide is a toroidal ray guide and each of the first imaging surface, the second imaging surface, the entrance pupil and the exit pupil are aspherical in radial cross section.

### Claim 19

A method comprising:
emanating radiation from an extended source disposed along an optical axis at an angle between 40 and 140 degrees from the optical axis;
receiving the emanated radiation at an entrance pupil of a ray guide arrangement, said ray guide arrangement being circularly symmetric about the optical axis; and
redirecting the received radiation through the ray guide arrangement to an exit pupil in an average direction substantially parallel to the optical axis;
wherein the ray guide arrangement is arranged such that the entrance pupil is substantially imaged to the exit pupil.

### Claim 20 (depends on 19)

The method of claim 19, wherein the received radiation comprises light having substantially circular angular distribution and the redirected radiation comprises redirected light at the exit pupil having substantially uniform rectilinear angular distribution.

### Claim 21 (depends on 19)

The method of claim 19, wherein the angle is between 45 and 135 degrees.

### Claim 22 (depends on 19)

The method of claim 19, wherein the circularly symmetric ray guide arrangement comprises first and second imaging surfaces disposed between the entrance pupil and the exit pupil that form an intermediate image from the received light.

### Claim 23 (depends on 22)

The method of claim 22, wherein the circularly symmetric ray guide arrangement comprises a first toroidal ray guide and a second ray guide arranged in optical series with one another, wherein the first toroidal ray guide defines the entrance pupil and the first imaging surface and the second ray guide defines the exit pupil and the second imaging surface.

### Claim 24 (depends on 23)

The method of claim 23, wherein the circularly symmetric ray guide arrangement further comprises a third toroidal ray guide arranged in optical series with the second ray guide and in optical parallel with the first toroidal ray guide, said third toroidal ray guide defining another entrance pupil.

### Claim 25 (depends on 23)

The method of claim 23, wherein a surface of the first toroidal ray guide outboard from the optical axis comprises a reflective surface.

### Claim 26 (depends on 24)

The method of claim 24, wherein the radiation comprises light and wherein redirecting the received light through the circularly symmetric ray guide arrangement comprises:
guiding substantially all light incident upon the entrance pupil of the first toroidal ray guide from the source through the first toroidal ray guide and to the first imaging surface; and
guiding substantially all light incident upon the another entrance pupil of the third toroidal ray guide from the source through the third toroidal ray guide and to the third imaging surface.

### Claim 27 (depends on 23)

The method of claim 23, wherein emanating radiation from the source comprises propagating the radiation through a substantially hemispherical dome that faces the entrance pupil.

### Claim 28 (depends on 23)

The method of claim 23, wherein the entrance pupil comprises a fourth imaging surface.

### Claim 29 (depends on 28)

The method of claim 28, wherein the fourth imaging surface is adapted to form an intermediate image from the source at a plane perpendicular to the optical axis and adjacent to the first imaging surface.

### Claim 30 (depends on 29)

The method of claim 29, wherein the second ray guide comprises a fifth imaging surface disposed opposite the second imaging surface.

### Claim 31 (depends on 23)

The method of claim 23, wherein the second ray guide is a toroidal ray guide.

### Claim 32 (depends on 9)

The apparatus of claim 9, wherein the light source comprises a plurality of light sources.

### Claim 33 (depends on 32)

The apparatus of claim 32, wherein the light sources comprise light emitting diodes.

### Claim 34 (depends on 33)

The apparatus of claim 33, wherein the light emitting diodes emit different colors.

### Claim 35 (depends on 34)

The apparatus of claim 34, wherein the source comprises further at least one light pipe between the light emitting diodes and the entrance pupil.

### Claim 36 (depends on 34)

The apparatus of claim 34, further comprising a fly's eye lens disposed opposite an exit pupil defined by the second ray guide which is a second toroidal ray guide.

### Claim 37 (depends on 23)

The method of claim 23, in which the source comprises a plurality of different color light emitting diodes.

### Claim 38 (depends on 37)

The method of claim 37, in which emanating radiation from the source comprises guiding light from the plurality of different color light emitting diodes through a lightpipe prior to receiving the emanated radiation at the entrance pupil.

### Claim 39 (depends on 37)

The method of claim 37, further comprising passing the radiation from the exit pupil through a fly's eye lens.

### Claim 40 (depends on 37)

The method of claim 37, further comprising passing the radiation from the exit pupil through at least one micro-lens array.

### Claim 41 (depends on 34)

The apparatus of claim 34, further comprising at least one micro-lens array disposed opposite an exit pupil defined by the second ray guide which is a second toroidal ray guide.