# US 10,120,266 B2 · Thin LED flash for camera

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 10,120,266 B2
- Document ID: US10120266B2
- Status: Granted
- Kind: B2
- Application number: 15/104,220
- Filed: 2014-12-22
- Published: 2016-11-03
- Granted: 2018-11-06
- Earliest claimed: 2014-01-06
- Assignees: Lumileds LLC
- Applicants: Lumileds LLC
- Inventors: Mark Melvin Butterworth
- Web page: https://patentgrep.com/patent/US10120266B2

## CPC

- G03B 15/05: Combinations of cameras with electronic flash apparatus; Electronic flash units
- H10H 20/8514: {characterised by their shape, e.g. plate or foil}
- H10H 20/855: Optical field-shaping means, e.g. lenses
- H10H 20/856: Reflecting means
- G03B 2215/0567: Solid-state light source, e.g. LED, laser
- H10H 20/8511: {characterised by their material, e.g. binder}
- G03B: APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR (optical parts of such apparatus G02B; photosensitive materials or processes for photographic purposes G03C; apparatus for processing exposed photographic materials G03D)
- H10H: INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS

## Abstract

A thin flash module for a camera uses a flexible circuit as a support surface. A blue GaN-based flip chip LED die is mounted on the flex circuit. The LED die has a thick transparent substrate forming a “top” exit window so at least 40% of the light emitted from the die is side light. A phosphor layer conformally coats the die and a top surface of the flex circuit. A stamped reflector having a knife edge rectangular opening surrounds the die. Curved surfaces extending from the opening reflect the light from the side surfaces to form a generally rectangular beam. A generally rectangular lens is affixed to the top of the reflector. The lens has a generally rectangular convex surface extending toward the die, wherein a beam of light emitted from the lens has a generally rectangular shape corresponding to an aspect ratio of the camera's field of view.

## Claims

### Claim 1

A light emitting device comprising:
a support structure;
a light emitting diode (LED) die mounted on the support structure,
the LED die having a top surface and at least one side surface and comprising LED semiconductor layers and a transparent substrate, the substrate comprising the top surface of the LED die so that the LED die has anode and cathode electrodes on a bottom surface, the substrate being thicker than the LED semiconductor layers, wherein light emitted from the side surfaces is at least 30% of all light emitted by the LED;
a phosphor layer covering the top surface and side surfaces;
a reflector surrounding the LED die, the reflector having curved surfaces surrounding the LED die, wherein the curved surfaces extend from a generally rectangular opening for the LED die and reflect the light from the side surfaces of the LED die to form a generally rectangular beam; and
a generally rectangular lens affixed to walls of the reflector, the lens having a generally rectangular convex surface extending toward the LED die and a flat top surface facing away from the LED die.

### Claim 2 (depends on 1)

The device of claim 1, wherein the device is a flash for a camera.

### Claim 3 (depends on 2)

The device of claim 2, wherein an aspect ratio of the beam is substantially the same as an aspect ratio of a field of view of the camera.

### Claim 4 (depends on 1)

The device of claim 1, wherein the support structure is a flexible circuit.

### Claim 5 (depends on 1)

The device of claim 1, wherein the reflector comprises a stamped metal reflector, where the opening has a knife edge facing the LED die.

### Claim 6 (depends on 1)

The device of claim 1, wherein the lens has a focal length and wherein a distance from a side of the LED die, taken normal to the side of the LED die, to the reflector plus a distance from the reflector to the lens is approximately the focal length.

### Claim 7 (depends on 1)

The device of claim 1, wherein light from the at least one side surface of the LED die is at least 40% of all light emitted by the LED die.

### Claim 8 (depends on 1)

The device of claim 1, wherein light from the at least one side surface of the LED die is at least 50% of all light emitted by the LED die.

### Claim 9 (depends on 1)

The device of claim 1, wherein the substrate is a growth substrate for the LED semiconductor layers.

### Claim 10 (depends on 1)

The device of claim 1, wherein the phosphor layer conformally coats the top surface and the at least one side surface and has substantially uniform thickness.

### Claim 11 (depends on 1)

The device of claim 1, wherein the phosphor layer comprises phosphor particles infused in a binder, wherein the phosphor layer covers a portion of a top surface of the support structure, and wherein a bottom surface of the reflector is affixed to the support structure by the binder acting as an adhesive.

### Claim 12 (depends on 1)

The device of claim 1, wherein a footprint of the reflector is substantially the same as a footprint of the support structure.

### Claim 13 (depends on 1)

The device of claim 1, wherein a total height of the device is less than 1 mm.

### Claim 14 (depends on 1)

The device of claim 1, wherein a total height of the device is less than 2 mm.