# US 8,786,519 B2 · Head up display utilizing an LCD and a diffuser

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- Number: US 8,786,519 B2
- Document ID: US8786519B2
- Status: Granted
- Kind: B2
- Application number: 12/920,721
- Filed: 2009-03-02
- Published: 2011-03-03
- Granted: 2014-07-22
- Earliest claimed: 2008-03-04
- Assignees: Elbit Systems Ltd.
- Applicants: Yoel Blumenfeld; Ofer Sinai; Shmuel Roth; Guy Kaufman
- Inventors: Yoel Blumenfeld; Ofer Sinai; Shmuel Roth; Guy Kaufman
- Web page: https://patentgrep.com/patent/US8786519B2

## CPC

- G02B 17/006: {Systems in which light light is reflected on a plurality of parallel surfaces, e.g. louvre mirrors, total internal reflection [TIR] lenses (Fresnel mirrors G02B5/09, Fresnel lenses G02B3/08)}
- G02B 27/0081: {with means for altering, e.g. enlarging, the entrance or exit pupil}
- G02B 27/0101: {characterised by optical features (G02B27/0172 takes precedence)}
- G02B 5/02: Diffusing elements; Afocal elements
- G02B 5/30: Polarising elements (light-modulating devices with active elements G02F1/00)
- G02B 6/00: Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B 2027/0125: {Field-of-view increase by wavefront division}
- G02B 2027/0145: {creating an intermediate image}
- G02B 2027/015: {involving arrangement aiming to get less bulky devices}
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS

## Abstract

Head up display (HUD) for displaying a combined image of a scene image of a scene and an informative image, for an observer, the HUD including an image source, an optical relay, a low physical height horizontally expanding optical assembly and a planar optical module, the image source for producing a substantially small narrow angle informative image, the optical relay for producing a substantially large narrow angle informative image, by enlarging the substantially small narrow angle informative image, received from the image source, the low physical height horizontally expanding optical assembly for producing a horizontally expanded image, by horizontally expanding the substantially large narrow angle informative image, received from the optical relay, and the planar optical module for producing a substantially large informative image, by vertically expanding the horizontally expanded image, and further producing the combined image, by combining the substantially large informative image with the scene image.

## Claims

### Claim 1

Head up display (HUD) for displaying a combined image of, a scene image of a scene and an informative image, for an observer, the HUD comprising:
an image source for producing a substantially small narrow angle informative image, said informative image including information for presentation to said observer;
an optical relay for producing a substantially large narrow angle informative image, by enlarging said substantially small narrow angle informative image, received from said image source;
a horizontally expanding optical assembly for producing a horizontally magnified image, by horizontally magnifying said substantially large narrow angle informative image, received from said optical relay, said horizontally expanding optical assembly being of low physical height; and
a planar optical module including:
a planar light guide;
a reflector for directing said horizontally expanded image into said planar light guide as a reflected light beam; and
a plurality of beam splitters, each of said beam splitters directing a respective portion of said reflected light beam toward said observer in a direction substantially normal to said planar optical module, wherein each of said respective portion of said reflected light beam including all said information of said informative image to be presented to said observer, each of said beam splitters directing another respective portion of said reflected light beam toward a consecutive one of said beam splitters, each of said beam splitters producing said combined image by combining said scene image with said respective portion of said reflected light beam.

### Claim 2 (depends on 1)

The HUD according to claim 1, further comprising a diffuser optically coupled after said optical relay and before said horizontally expanding optical assembly for producing a substantially wide angle image, by diffusing said substantially large narrow angle image, received from said optical relay.

### Claim 3 (depends on 1)

The HUD according to claim 1, wherein said planar optical module directs said combined image toward an eye of said observer, located on a side of said planar optical module, opposite that of said image source.

### Claim 4 (depends on 1)

The HUD according to claim 1, wherein said planar optical module directs said combined image toward an eye of said observer, located on the same side of said planar optical module, as that of said image source.

### Claim 5 (depends on 1)

The HUD according to claim 1, further comprising a light source, for producing a point like source of light, for illuminating said substantially small narrow angle informative image.

### Claim 6 (depends on 5)

The HUD according to claim 5, further comprising a backlight optics, for homogenizing said point-like source of light emitted by said light source and for producing a uniform beam of light.

### Claim 7 (depends on 5)

The HUD according to claim 5, wherein said light source is a light emitting diode (LED).

### Claim 8 (depends on 5)

The HUD according to claim 5, wherein said light source is a laser.

### Claim 9 (depends on 5)

The HUD according to claim 5, wherein said light source has a substantially small physical size.

### Claim 10 (depends on 6)

The HUD according to claim 6, wherein said backlight optics is an optical device selected from the list consisting of:
a fiber optic light guide;
a light guide filled with a light transmitting fluid;
a fly eyes homogenizer; and
a set of one or more lenses.

### Claim 11 (depends on 1)

The HUD according to claim 1, wherein said image source is selected from the list consisting of:
a two dimensional LCD;
a cathode ray tube (CRT);
a digital matrix display micromirror device (DMD); and
a liquid crystal on silicon (LCOS).

### Claim 12 (depends on 1)

The HUD according to claim 1, wherein said low physical height horizontally expanding optical assembly is in the form of a portion of an equiconvex lens.

### Claim 13 (depends on 1)

The HUD according to claim 1, wherein said reflector is oriented at an angle relative to the direction of said horizontally expanded image.

### Claim 14 (depends on 1)

The HUD according to claim 1, wherein each of said plurality of beam splitters is oriented at an angle relative to the direction of said horizontally expanded image, such that said respective portion of said reflected light beam is directed away from said image source and toward said observer, wherein said observer is located on an opposite side of said image source.

### Claim 15 (depends on 1)

The HUD according to claim 1, wherein each of said plurality of beam splitters is oriented at an angle relative to the direction of said horizontally expanded image, such that said respective portion of said reflected light beam is directed away from said image source and toward said observer, wherein said observer is located on the same side of said image source.

### Claim 16 (depends on 1)

The HUD according to claim 1, wherein said horizontally expanding optical assembly is of a lower physical height which is substantially smaller than the physical width of said horizontally expanding optical assembly and smaller than the height of the planer optical.

### Claim 17 (depends on 1)

The HUD according to claim 1, wherein said substantially large narrow angle informative image produced by said optical replay is substantially large comparing to said substantially small narrow angle informative image received from said image source.