# US 12,001,043 B2 · Optical device for controlling light from an external light source

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- Number: US 12,001,043 B2
- Document ID: US12001043B2
- Status: Granted
- Kind: B2
- Application number: 17/756,734
- Filed: 2020-12-04
- Published: 2023-01-19
- Granted: 2024-06-04
- Earliest claimed: 2019-12-04
- Assignees: Vitrealab GmbH; Consiglio Nazionale Delle Ricerche
- Applicants: VitreaLab GmbH; Consiglio Nazionale Delle Ricerche
- Inventors: Jonas Zeuner; Chiara Greganti; Roberto Osellame
- Web page: https://patentgrep.com/patent/US12001043B2

## CPC

- G02B 6/0036: {2-D arrangement of prisms, protrusions, indentations or roughened surfaces}
- G02B 6/0075: {Arrangements of multiple light guides (G02B6/0028 takes precedence)}
- G02B 6/12002: {Three-dimensional structures}
- G02B 2006/12159: {Interferometer}
- G03H 1/0005: {Adaptation of holography to specific applications (holographic optical element G02B5/32; holographic scanner G02B26/106; recognition using holographic mask G06V10/88; holographic memories G11B7/0065, G11C13/042)}
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G03H: HOLOGRAPHIC PROCESSES OR APPARATUS (holograms, e.g. point holograms, used as ordinary optical elements G02B5/32; producing stereoscopic or other three-dimensional effects G02B30/00; diffraction-grating systems G02B27/44; systems using moiré fringes G02B27/60; optical logic elements G02F3/00; stereo-photography G03B35/00; photosensitive materials or processes for photographic purposes G03C; {stereo-photographic or similar processes G03C9/00}; apparatus for processing exposed photographic materials G03D; analogue computers performing mathematical operations with the aid of optical elements G06E3/00; authentication by radiation, of concealed information carried by holograms or diffraction gratings G06K19/16; holographic storage G11B7/0065, G11C13/04; {stereoscopic or other three dimensional effects in television systems H04N13/00})

## Abstract

An optical device for controlling light from an external light source including: at least a first and a second waveguide for guiding a light beam emitted from the external light source; and at least a first beam shaping structure with a first light emitting area for emitting a light beam and a second beam shaping structure with a second light emitting area for emitting a light beam, wherein the first waveguide guides the light beam emitted from the external light source to the first beam shaping structure and the second waveguide guides the light beam emitted from the external light source to the second beam shaping structure; wherein the first and the second beam shaping structure-are each configured such that the uniformity of the radiant density profile of a light beam emitted from the respective light emitting area of the respective beam shaping structure is higher than that of the light beam guided to the respective beam shaping structure by the respective waveguide. Backlight unit including such an optical device; and optical system, in particular holographic display, including such a backlight unit and a spatial light modulator.

## Claims

### Claim 1

Optical device for controlling light from an external light source comprising:
at least a first and a second waveguide for guiding a light beam emitted from the external light source, and
at least a first beam shaping structure with a first light emitting area for emitting a light beam and a second beam shaping structure with a second light emitting area for emitting a light beam, wherein the first waveguide guides the light beam emitted from the external light source to the first beam shaping structure and the second waveguide guides the light beam emitted from the external light source to the second beam shaping structure,
wherein
the first and the second beam shaping structure are each configured such that the uniformity of the radiant density profile of a light beam emitted from the respective light emitting area of the respective beam shaping structure is higher than that of the light beam guided to the respective beam shaping structure by the respective waveguide, and
wherein an optical beam divergence reducing structure is provided for reducing the beam divergence of the light beams emitted from the first and the second light emitting area.

### Claim 2 (depends on 1)

The optical device according to claim 1, wherein the first and the second beam shaping structure each comprise an optical shaping element and the first and the second waveguides direct the light beam emitted from the external light source at the respective optical shaping element of the first and the second beam shaping structure, and the optical shaping elements are configured for manipulating the wavefront of the light beam directed at the respective optical shaping element.

### Claim 3 (depends on 2)

The optical device according to claim 2, wherein the optical shaping element of the first and/or the second beam shaping structure is an optical profiler element configured to increase the uniformity of the radiant intensity profile of the light beam directed at the respective optical shaping element.

### Claim 4 (depends on 2)

The optical device according to claim 2 , wherein the optical shaping element of the first and/or the second beam shaping structure is an optical diverging element configured to increase the beam divergence of the light beam directed at the respective optical diverging element.

### Claim 5 (depends on 2)

The optical device according to claim 2, wherein the optical device comprises an interface, wherein the first and the second light emitting area are provided by the interface and are each delimited by total internal reflection occurring outside the respective light emitting area for the light beam directed towards the interface after interfering with the respective optical shaping element.

### Claim 6 (depends on 5)

The optical device according to claim 5, wherein the first light emitting area is non-overlapping with the second light emitting area.

### Claim 7 (depends on 1)

The optical device according to claim 1, wherein the optical device comprises a light emitting surface, wherein the first and the second light emitting area are provided by the light emitting surface and wherein a honeycomb structure of an absorptive material is provided on top of the light emitting surface, wherein a first cell of the honeycomb structure encompasses the first light emitting area and a second cell of the honeycomb structure encompasses the second light emitting area.

### Claim 8 (depends on 1)

The optical device according to claim 1, wherein the optical device comprises at least one bus waveguide for guiding the light beam emitted from the external light source and at least a first and a second optical coupler, wherein the first optical coupler couples light emitted from the external light source from the bus waveguide to the first waveguide and the second optical coupler couples the light beam emitted from the external light source from the bus waveguide to the second waveguide.

### Claim 9 (depends on 1)

The optical device according to claim 1, further comprising a transparent substrate, wherein the first and the second waveguide are formed within the transparent substrate.

### Claim 10 (depends on 9)

Optical device according to claim 9, wherein at least a first and a second interferometer waveguide formed within the substrate,
a first interferometer coupler for coupling a light beam from the first interferometer waveguide to the second interferometer waveguide,
a second optical interferometer coupler for coupling a light beam from the first interferometer waveguide to the second interferometer waveguide, and
a photodetector connected to the first interferometer waveguide.

### Claim 11 (depends on 1)

Optical device according to claim 1, wherein it is configured for controlling light from at least one further external light source.

### Claim 12 (depends on 1)

Backlight unit, comprising an optical device according to claim 1 and comprising the external light source as a laser.

### Claim 13 (depends on 12)

Optical system comprising a holographic display, and comprising a spatial light modulator, and further comprising a backlight unit according to claim 12.

### Claim 14

Optical device for controlling light from an external light source comprising:
at least a first and a second waveguide for guiding a light beam emitted from the external light source, and
at least a first beam shaping structure with a first light emitting area for emitting a light beam and a second beam shaping structure with a second light emitting area for emitting a light beam, wherein the first waveguide guides the light beam emitted from the external light source to the first beam shaping structure and the second waveguide guides the light beam emitted from the external light source to the second beam shaping structure,
wherein
the first and the second beam shaping structure are each configured such that the uniformity of the radiant density profile of a light beam emitted from the respective light emitting area of the respective beam shaping structure is higher than that of the light beam guided to the respective beam shaping structure by the respective waveguide,
wherein the first and the second beam shaping structure each comprise an optical shaping element and the first and the second waveguides direct the light beam emitted from the external light source at the respective optical shaping element of the first and the second beam shaping structure, and the optical shaping elements are configured for manipulating the wavefront of the light beam directed at the respective optical shaping element, and
wherein the optical device comprises an interface, wherein the first and the second light emitting area are provided by the interface and are each delimited by total internal reflection occurring outside the respective light emitting area for the light beam directed towards the interface after interfering with the respective optical shaping element.

### Claim 15 (depends on 14)

The optical device according to claim 14, wherein the optical shaping element of the first and/or the second beam shaping structure is an optical profiler element configured to increase the uniformity of the radiant intensity profile of the light beam directed at the respective optical shaping element.

### Claim 16 (depends on 14)

The optical device according to claim 14, wherein the first light emitting area is non-overlapping with the second light emitting area.

### Claim 17 (depends on 14)

The optical device according to claim 14, wherein the optical device comprises at least one bus waveguide for guiding the light beam emitted from the external light source and at least a first and a second optical coupler, wherein the first optical coupler couples light emitted from the external light source from the bus waveguide to the first waveguide and the second optical coupler couples the light beam emitted from the external light source from the bus waveguide to the second waveguide.

### Claim 18

Optical device for controlling light from an external light source comprising:
at least a first and a second waveguide for guiding a light beam emitted from the external light source, and
at least a first beam shaping structure with a first light emitting area for emitting a light beam and a second beam shaping structure with a second light emitting area for emitting a light beam, wherein the first waveguide guides the light beam emitted from the external light source to the first beam shaping structure and the second waveguide guides the light beam emitted from the external light source to the second beam shaping structure,
wherein
the first and the second beam shaping structure are each configured such that the uniformity of the radiant density profile of a light beam emitted from the respective light emitting area of the respective beam shaping structure is higher than that of the light beam guided to the respective beam shaping structure by the respective waveguide,
wherein the optical device comprises a light emitting surface, wherein the first and the second light emitting area are provided by the light emitting surface and wherein a honeycomb structure of an absorptive material is provided on top of the light emitting surface, wherein a first cell of the honeycomb structure encompasses the first light emitting area and a second cell of the honeycomb structure encompasses the second light emitting area.

### Claim 19

Optical device for controlling light from an external light source comprising:
at least a first and a second waveguide for guiding a light beam emitted from the external light source, and
at least a first beam shaping structure with a first light emitting area for emitting a light beam and a second beam shaping structure with a second light emitting area for emitting a light beam, wherein the first waveguide guides the light beam emitted from the external light source to the first beam shaping structure and the second waveguide guides the light beam emitted from the external light source to the second beam shaping structure,
wherein
the first and the second beam shaping structure are each configured such that the uniformity of the radiant density profile of a light beam emitted from the respective light emitting area of the respective beam shaping structure is higher than that of the light beam guided to the respective beam shaping structure by the respective waveguide,
further comprising a transparent substrate, wherein the first and the second waveguide are formed within the transparent substrate, and
wherein at least a first and a second interferometer waveguide formed within the transparent substrate,
a first interferometer coupler for coupling a light beam from the first interferometer waveguide to the second interferometer waveguide,
a second optical interferometer coupler for coupling a light beam from the first interferometer waveguide to the second interferometer waveguide, and
a photodetector connected to the first interferometer waveguide.
