# US 9,041,046 B2 · Method and apparatus for a light source

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- Number: US 9,041,046 B2
- Document ID: US9041046B2
- Status: Granted
- Kind: B2
- Application number: 13/664,278
- Filed: 2012-10-30
- Published: 2013-02-28
- Granted: 2015-05-26
- Earliest claimed: 2011-03-15
- Assignees: Avago Technologies General IP (Singapore) Pte. Ltd.
- Applicants: Avago Technologies General IP (Singapore) Pte. Ltd.
- Inventors: Chin Ewe Phang; Seong Choon Lim; Eng Chuan Ong
- Web page: https://patentgrep.com/patent/US9041046B2

## CPC

- H10H 20/852: Encapsulations
- H10H 20/8506: {Containers}
- H10H 20/8515: {not being in contact with the bodies}
- H10H 20/8516: {having a non-uniform spatial arrangement or non-uniform concentration, e.g. patterned wavelength conversion layer or wavelength conversion layer with a concentration gradient}
- G03B 2215/0567: Solid-state light source, e.g. LED, laser
- H10H 20/0361: {of wavelength conversion means}
- H10H 20/0362: {of encapsulations}
- H10H 20/856: Reflecting means
- H10W 72/01515: {Forming coatings}
- H10W 72/075: {of bond wires}
- H10W 74/00: Encapsulations, e.g. protective coatings
- H10W 90/00: Package configurations
- H10W 90/754: {between a chip and a stacked insulating package substrate, interposer or RDL}
- H10H: INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS
- 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)
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10

## Abstract

A light-emitting device having a light source die mounted within an aperture is disclosed. The aperture is covered by a die attach pad on one side. The light source die is mounted on a die attach pad within the aperture. In one embodiment, an optical coupling layer can be formed within an aperture encapsulating a light source die. A wavelength converting layer can be formed on the substrate above the optical coupling layer. The wavelength converting layer can comprise a high density layer and a low density layer. The high density layer can comprise wavelength-converting material precipitated on one side of the wavelength converting layer. The low density layer can comprise the wavelength-converting material in particle form suspended within the wavelength converting layer. In one embodiment, the wavelength converting layer may be confined within the aperture of the substrate.

## Claims

### Claim 1

A light-emitting device, comprising:
a substrate having opposing first and second surfaces;
an aperture extending through the substrate from the first surface to the second surface of the substrate;
a die attach pad configured to cover the aperture at the first surface;
a light source die attached to the die attach pad;
an optical coupling layer substantially encapsulating the light source die within the aperture;
a wavelength converting layer formed on the optical coupling layer, wherein the wavelength converting layer comprises a low density layer and a high density layer; and
a wavelength-converting material formed within the wavelength converting layer;
wherein the high density layer has substantially higher density of the wavelength-converting material relative to the low density layer such that the wavelength converting material in the low density layer is suspended within the low density layer in particle form
but the wavelength-converting material in the high density layer is precipitated on one side of wavelength converting layer.

### Claim 2 (depends on 1)

The light-emitting device of claim 1 further comprising an additional optical coupling layer, wherein the wavelength converting layer is sandwiched between the optical coupling layer and the additional optical coupling layer.

### Claim 3 (depends on 2)

The light-emitting device of claim 2, wherein the additional optical coupling layer is substantially planarly parallel to the second surface of the substrate.

### Claim 4 (depends on 3)

The light-emitting device of claim 3, wherein the additional optical coupling layer covers entirely the second surface of the substrate.

### Claim 5 (depends on 2)

The light-emitting device of claim 2, wherein the wavelength converting layer is formed within the aperture.

### Claim 6 (depends on 5)

The light-emitting device of claim 5, wherein:
the high density layer has a thickness and the low density layer has a thickness; and
the thickness of the high density layer is at least more than the thickness of the low density layer.

### Claim 7 (depends on 2)

The light-emitting device of claim 2, wherein the wavelength converting layer, the optical coupling layer and the additional optical coupling layer are formed using substantially the same type of encapsulant.

### Claim 8 (depends on 1)

The light-emitting device of claim 1, wherein the high density layer of the wavelength converting layer covers entirely the second surface of the substrate.

### Claim 9 (depends on 1)

The light-emitting device of claim 1, wherein the wavelength converting layer is formed adjacent to the second surface of the substrate and outside the aperture.

### Claim 10 (depends on 9)

The light-emitting device of claim 9, wherein:
the high density layer has a thickness and the low density layer has a thickness; and
the thickness of the high density layer is less than approximately half of the thickness of the low density layer.

### Claim 11 (depends on 1)

The light-emitting device of claim 1, wherein the light-emitting device forms a portion of a camera device.

### Claim 12 (depends on 1)

The light-emitting device of claim 1, wherein the density of the wavelength-converting material in the high density layer is substantially higher than the low density layer such that the wavelength-converting material in the low density layer is distinguishably visible under a microscope but the wavelength-converting material in the high density layer is visually visible.

### Claim 13

A flash system for use in a mobile device, comprising:
a substrate having opposing first and second surfaces;
a plurality of conductors being form on at least one of the first and second surfaces;
an aperture extending through the substrate, from the first surface to the second surface of the substrate;
a die attach pad extending over and covering the first surface of the substrate;
a light source die attached on the die attach pad and disposed substantially within the aperture;
an optical coupling layer encapsulating the light source die; and
a wavelength converting layer comprising a low density layer and a high density layer disposed on the optical coupling layer such that the optical coupling layer is sandwiched between the wavelength converting layer and the die attach pad, wherein the high density layer has substantially higher density relative to the low density layer such that the low density layer is distinguishably visible under a microscope whereas the high density layer is visually visible precipitated particles on one side of the wavelength-converting material.

### Claim 14 (depends on 13)

The flash system of claim 13, wherein the high density layer has a substantially uniform thickness.

### Claim 15 (depends on 13)

The flash system of claim 13, wherein the wavelength converting layer is disposed within the aperture.

### Claim 16 (depends on 15)

The flash system of claim 15, wherein the flash system further comprises an additional optical coupling layer disposed on the second surface of the substrate covering an opening of the aperture at the second surface of the substrate.

### Claim 17

A lighting apparatus, comprising:
a substrate having a opposing first and second surfaces;
first and second apertures extending through the substrate from the first surface to the second surface of the substrate;
first and second die attach pads adjacent to the first surface of the substrate and substantially covering the first and second apertures;
a first light source die attached on the first die attach pad and disposed substantially within the first aperture for emitting light;
a second light source die attached on the second die attach pad and disposed substantially within the second aperture for emitting light;
a first optical coupling layer encapsulating the first light source die within the first aperture;
a wavelength converting layer formed on the first optical coupling layer but being confined within the first aperture, the wavelength converting layer being configured to cover the first light source die so as to convert the light emitted from the first light source die into a broader spectrum light; and
a second optical coupling layer encapsulating the second light source die, the wavelength converting layer that covers the first light source die and at least a portion of the second surface of the substrate such that the second optical coupling layer is configured to mix light emitted from the second light source die with the broader spectrum light from the wavelength converting layer.

### Claim 18 (depends on 17)

The lighting apparatus of claim 17, wherein the wavelength converting layer comprises:
a low density layer of wavelength converting particles; and
a high density layer of the wavelength converting particles connected to the low density layer, wherein the high density layer has substantially higher concentration of the wavelength-converting particles relative to the low density layer such that the wavelength-converting particles in the high density layer is precipitated but the wavelength-converting particles in the low density layer is in particle form suspending within the low density layer.

### Claim 19 (depends on 18)

The lighting apparatus of claim 18 further comprising a third light source die and a fourth light source die encapsulated by the second optical coupling layer, wherein light emitted by the third and fourth light source dies are mixed with the light emitted from the second light source die within the second optical coupling layer.

### Claim 20 (depends on 19)

The lighting apparatus of claim 19, wherein:
the first light source die and the wavelength converting layer are configured to generate white light;
the second light source die is configured to generate light of a first color;
the third light source die is configured to generate red light of a second color; and
the fourth light source die is configured to generate light of a third color.