Light Source With Glass Housing

Abstract

A light source comprising at least one light-emitting diode (2), which emits light, and a housing (5) arranged to receive at least a portion of said light is provided. The housing (5) comprises a translucent glass material and is provided with at least one recess (4) that comprises positioning and orientating means. The at least one light-emitting diode (2) is arranged in said at least one recess (4), is positioned and orientated by said positioning and orientating means and is bonded to said housing. By utilizing a fully inorganic approach for the housing, the temperature stability of the light source is improved.

Description

TECHNICAL FIELD[0001]The present invention relates to a light source comprising at least one light-emitting diode, which emits light, and a housing arranged to receive at least a portion of said light. The present invention further relates to a method for the manufacture of such a light source.TECHNICAL BACKGROUND[0002]Semiconductor light-emitting devices, such as light-emitting diodes (LEDs) and laser diodes (LDs), are among the most efficient and robust light sources currently available.[0003]Light extraction is a key issue for light emitting devices. A common problem of semiconductor light-emitting devices is that the efficiency with which light may be extracted from the device is reduced due to internal reflection in the interface between the device and the surroundings, followed by re-absorption of the reflected light in the device. The internal reflection is due to that the refractive index of the device materials is higher than the refractive index of the material in which th...

AI Technical Summary

Benefits of technology

[0012]An advantage with a light source of the present invention is that the crystalline substrate of the LED(s) is bonded to the glass housing. Thus, no organic adhesives are needed, and the light source will be temperature stable. Further, in the present invention, a LED is arranged in preformed recesses in the housing. As the step of forming the housing is separate from the step of bonding the LEDs to the housing, the processing temperatures for forming the housing may be higher than the breakdown temperature of the LED, as long as the temperature at which the LED is bonded to the housing is below this breakdown temperature. Thus, the processing temperature of the housing is independent from the breakdown temperature of the LEDs. In embodiments of the present invention, the walls of the at least one recess may constitute the positioning and orientating means.

[0021]One advantage of this embodiment is that the LEDs are connected to the circuitry after the LEDs are bonded to the housing. Thus, the circuitry is not exposed to the high temperatures in the steps of processing the housing and bonding the LEDs. Another advantage is that the LEDs are arranged in fixed positions and orientations by the housing. Therefore, the circuitry may be arranged on a sub-mount in a pattern corresponding to the predetermined fixed positions and orientations of the LEDs. This simplifies mass production and assembly of the light source of the present invention.

Problems solved by technology

Light extraction is a key issue for light emitting devices.

A common problem of semiconductor light-emitting devices is that the efficiency with which light may be extracted from the device is reduced due to internal reflection in the interface between the device and the surroundings, followed by re-absorption of the reflected light in the device.

However, in high power applications, where single solid-state light emitting devices with an effect of up to 3 Watts per square mm or arrays of such devices, with a total effect of up to 100 Watts or more, a lot of heat is dissipated from the light emitting devices.

However, the processing temperature for connecting the coating material and the light emitting element must be low, e.g. lower than ˜350° C., or otherwise, the n / p-junctions in the light emitting element will be damaged.

However, substrates and circuitry on which light-emitting semiconductor devices are arranged are often heat sensitive.

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