# US 11,079,630 B1 · Wide lateral angle frontlight for use with reflective displays

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- Number: US 11,079,630 B1
- Document ID: US11079630B1
- Status: Granted
- Kind: B1
- Application number: 16/713,695
- Filed: 2019-12-13
- Granted: 2021-08-03
- Earliest claimed: 2019-12-13
- Assignees: Amazon Technologies, Inc.
- Applicants: Amazon Technologies, Inc.
- Inventors: Robert Arthur Sprague; Jerry Yee-Ming Chung
- Web page: https://patentgrep.com/patent/US11079630B1

## CPC

- G02F 1/1336: {Illuminating devices}
- G02F 1/133615: {Edge-illuminating devices, i.e. illuminating from the side}
- G02B 6/0031: {Reflecting element, sheet or layer}
- G02B 6/0036: {2-D arrangement of prisms, protrusions, indentations or roughened surfaces}
- G02B 6/0061: {to provide homogeneous light output intensity}
- G02B 6/0068: {Arrangements of plural sources, e.g. multi-colour light sources}
- G02B 6/0076: {Stacked arrangements of multiple light guides of the same or different cross-sectional area}
- G02B 6/0078: {Side-by-side arrangements, e.g. for large area displays}
- G02F 1/133524: {Light-guides, e.g. fibre-optic bundles, louvered or jalousie light-guides}
- G02F 1/133553: {Reflecting elements (associated to illuminating devices G02F1/133605)}
- G02F 1/133616: {Front illuminating devices}
- G02F 2203/02: reflective
- G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS

## Abstract

Devices, systems, and methods are provided for generating a wide angle frontlight for use with reflective displays. A display device may include a first end and a second end opposite the first end, and a first side and a second side opposite the first side. The display device may include a first light source, and a first light guide able to receive first light from the first light source. The display device may include a reflective display, the first light guide including a first refractive device, the first refractive device refracts a first portion of the first light toward the reflective display in a first direction toward the first side and to refract a second portion of the first light toward the reflective display in a second direction toward the second side, and the first direction separated from the second direction by a first angle of at least forty degrees.

## Claims

### Claim 1

A display device, comprising:
a top end and a bottom end opposite the top end;
a left side and a right side opposite the left side;
a first light source and a second light source, the first light source and the second light source positioned proximate to the top end of the display device;
a first light guide including first refractive features and extending linearly from the top end to the bottom end of the display device, the first light guide configured to receive first light from the first light source and second light from the second light source;
a reflective display configured to cause presentation of content using the first light and the second light; and
a second light guide extending linearly from the top end to the bottom end, the second light guide configured to receive a second portion of the second light from the second light source, the first light guide at least partially overlapping the second light guide, wherein a first axis spans from the top end to the bottom end, wherein the first light guide is positioned at a first angle with respect to the first axis, and wherein the second light guide is positioned at a second angle with respect to the first axis.

### Claim 2 (depends on 1)

The display device of claim 1, wherein:
the first refractive features are configured to:
refract a first portion of the first light toward the reflective display in a first direction toward the left side; and
refract a first portion of the second light toward the reflective display in a second direction toward the right side,
the first direction is at a third angle to the first axis,
the third angle is at least twenty degrees,
the second direction is at a fourth angle to the first axis, and
the fourth angle is at least twenty degrees.

### Claim 3 (depends on 1)

The display device of claim 1, wherein the first refractive features are configured to:
refract a first portion of the first light toward the reflective display in a first direction toward the left side; and
refract a first portion of the second light toward the reflective display in a second direction toward the right side, and
wherein the first direction is separated from the second direction by a third angle, wherein the third angle is along a transverse axis spanning from the left side to the right side.

### Claim 4 (depends on 3)

The display device of claim 3, wherein the third angle is at least thirty degrees.

### Claim 5 (depends on 1)

The display device of claim 1, wherein the first light guide further includes second refractive features, and wherein a first density of the first refractive features is substantially equal to a second density of the second refractive features.

### Claim 6 (depends on 1)

The display device of claim 1, wherein the first light guide further includes second refractive features, wherein the first refractive features have a first density and the second refractive features have a second density, wherein the first density is different than the second density.

### Claim 7 (depends on 6)

The display device of claim 6, wherein the first refractive features are positioned more proximate to the first light source than the second refractive features, and wherein the first density is less than the second density.

### Claim 8 (depends on 1)

The display device of claim 1, wherein a refractive feature of the first refractive features is positioned at a first third angle relative to the first axis, and wherein a second refractive feature of the first refractive features is positioned at a fourth angle relative to the first axis, and wherein the third angle is different than the fourth angle.

### Claim 9 (depends on 1)

The display device of claim 1, wherein a first refractive feature of the first refractive features is positioned at a third angle relative to the first axis, and wherein a second refractive feature of the first refractive features is positioned at a fourth angle relative to the first axis, and wherein the third angle relative to the first axis is equal to the fourth angle relative to the first axis.

### Claim 10 (depends on 9)

The display device of claim 9, wherein the first light guide further includes a third refractive feature of the first refractive features, the third refractive feature positioned at a fifth angle relative to the first axis, and wherein the fifth angle relative to the first axis is different than the third angle relative to the first axis and different than the fourth angle relative to the first axis.

### Claim 11 (depends on 1)

The display device of claim 1, wherein:
the second light guide includes second refractive features configured to refract the second portion of the second light toward the reflective display,
the first light guide directs the first light in a first direction, and
the second light guide directs the second light in a second direction, the first direction not parallel to the second direction.

### Claim 12 (depends on 11)

The display device of claim 11, wherein the first refractive features include a first number of the first refractive features, wherein the second light guide includes a second number of the second refractive features, and wherein the first number of the first refractive features is greater than the second number of the second refractive features.

### Claim 13 (depends on 1)

The display device of claim 1, wherein the first light guide further includes second refractive features, and wherein a first density of the first refractive features is substantially equal to a second density of the second refractive features.

### Claim 14

A device, comprising:
a top end and a bottom end opposite the top end;
a left side and a right side opposite the left side;
a first light source and a second light source positioned proximate to the top end of the device;
a first light guide including first refractive features and a second light guide including second refractive features, the first light guide and the second light guide extending linearly from the top end to the bottom end of the device, the first light guide configured to receive first light from the first light source, and the second light guide configured to receive second light from the second light source, the first light guide at least partially overlapping the second light guide, wherein the first light guide is positioned at a first angle with respect to a first axis that spans from the top end to the bottom end, and wherein the second light guide is positioned at a second angle with respect to the first axis; and
a reflective display configured to cause presentation of content using the first light and the second light.

### Claim 15 (depends on 14)

The device of claim 14, wherein:
the first refractive features are configured to:
refract a first portion of the first light toward the reflective display in a first direction toward the left side; and
refract a first portion of the second light toward the reflective display in a second direction toward the right side,
the first direction is at a third angle to the first axis,
the third angle is at least twenty degrees,
the second direction is at a fourth angle to the first axis, and
the fourth angle is at least twenty degrees.

### Claim 16 (depends on 14)

The device of claim 14, the second light guide configured to receive a third portion of the second light from the second light source
wherein the second light guide includes third refractive features configured to refract the third portion of the second light toward the reflective display.

### Claim 17 (depends on 14)

The device of claim 14, wherein the first light guide further includes third refractive features configured to refract a third portion of the first light toward the reflective display.

### Claim 18 (depends on 17)

The device of claim 17, wherein the first light guide includes a first density of the first refractive features and a second density of the third refractive features, wherein the first density is substantially equal to the second density.

### Claim 19

A display device, comprising:
a top end and a bottom end opposite the top end;
a left side and a right side opposite the left side;
a first light source and a second light source;
a first light guide including first refractive features and extending linearly from the top end to the bottom end of the display device, the first light guide configured to receive first light from the first light source and second light from the second light source;
a display configured to cause presentation of content using the first light and the second light; and
a second light guide extending linearly from the top end to the bottom end, the second light guide configured to receive a second portion of the second light from the second light source, the first light guide at least partially overlapping the second light guide, wherein a first axis spans from the top end to the bottom end, wherein the first light guide is positioned at a first angle with respect to the first axis, and wherein the second light guide is positioned at a second angle with respect to the first axis.

### Claim 20 (depends on 19)

The display device of claim 19, wherein:
the first refractive features are configured to:
refract a first portion of the first light toward the display in a first direction toward the left side; and
refract a first portion of the second light toward the display in a second direction toward the right side,
the first direction is at a third angle to the first axis, and
the second direction is at a fourth angle to the first axis.