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Exposed Pad LED Package

IP.com Disclosure Number: IPCOM000230111D
Publication Date: 2013-Aug-20
Document File: 3 page(s) / 82K

Publishing Venue

The IP.com Prior Art Database

Abstract

The demand for LED packages has been on the rise as more and more applications have adopted the use of these small footprint packages. LEDs are fast replacing conventional incandescent lighting systems due to their high luminous efficiency. Aside from superiority efficiency, there are many choices of light color available depending on the type of semiconductor material used. LEDs are produced in a variety of shapes and sizes. The type commonly seen is the 2 or 3 pins semi-spherical, resin encapsulated device. The exposed pad, non-leaded type of LED package is uncommon. The important components for making this type of LED package are the LED die, exposed pad leadframe, wires for interconnection and the clear encapsulation material. The steps in assembling this package are typically a standard assembly packaging process for QFN assembly. The package design and assembly method enable a thin package with an array IO layout and at low cost. The direct contact of the die to the exposed pad helps with the thermal management issue associated with LED assembly packaging.

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TITLE

Exposed Pad LED Package

ABSTRACT

The demand for LED packages has been on the rise as more and more applications have adopted the use of these small footprint packages.  LEDs are fast replacing conventional incandescent lighting systems due to their high luminous efficiency.  Aside from superiority efficiency, there are many choices of light color available depending on the type of semiconductor material used.  LEDs are produced in a variety of shapes and sizes. The type commonly seen is the 2 or 3 pins semi-spherical, resin encapsulated device. The exposed pad, non-leaded type of LED package is uncommon.  The important components for making this type of LED package are the LED die, exposed pad leadframe, wires for interconnection and the clear encapsulation material.  The steps in assembling this package are typically a standard assembly packaging process for QFN assembly.  The package design and assembly method enable a thin package with an array IO layout and at low cost.  The direct contact of the die to the exposed pad helps with the thermal management issue associated with LED assembly packaging.   

CONTENT

There are not many variants of LED packages in the industry. The common type of LED is the 2 or 3 pins semi-spherical, resin encapsulated package.  In this paper, a QFN type package is proposed for an LED.  This package offers several advantages over the conventional LED package.  First, the package can be very thin with small overall form factor.  This is possible with the deep cavity design and leadless terminal configuration.  Figure 1 shows the overall package configuration.

Figure 1 LED package configuration

Second, the assembly of this package is simple since it is commonly used for other types of devices such as sensors.  Therefore, packaging cost is low.  The package includes a down-set lead frame down-set that is formed from a standard process and available from lead...