Active solid-state devices (e.g. – transistors – solid-state diode – Responsive to non-electrical signal – Electromagnetic or particle radiation
Reexamination Certificate
2002-05-06
2004-08-24
Tran, Minhloan (Department: 2826)
Active solid-state devices (e.g., transistors, solid-state diode
Responsive to non-electrical signal
Electromagnetic or particle radiation
C257S080000, C257S081000, C257S098000, C257S099000, C257S100000, C257S103000, C257S444000
Reexamination Certificate
active
06781209
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to an optoelectronic component with a light emitting or light receiving element and a system carrier supporting said element for the support or installation of said component, an auxiliary carrier transparent to light in at least some areas or at least translucent and made of heat conducting material being provided, said auxiliary carrier being connected to the system carrier and thermally coupled to the element and having a recess through which light passes, together with a method for manufacturing such an optoelectronic component.
Light emitting or receiving optoelectronic components are becoming increasingly important with a view to providing fast and reliable data transmission media. In such components an optical coupling of the active element, usually made of semiconductor materials, to the environment or to an optical fibre is necessary. This places increased requirements on the housings which enclose the semiconductor elements, which must ensure adequate stability for use of the components under usual conditions.
Technologies used up to now for constructing surface emitting or receiving optoelectronic components such as light emitting diodes (LEDs) as incoherent light sources, or in particular surface emitting laser diodes, so-called VCSELs (Vertical Cavity Surface Emitting Lasers) as coherent light sources, have been manufactured up to now in metal housings of relatively large dimensions (in relation to the desired degree of miniaturisation) (TO housings) with transparent windows, and usually with very complex and therefore expensive manufacturing techniques. Also known are less expensive structures with completely moulded transparent housings of plastics material (for example, the customary LED housing) or pre-moulded plastic housings with moulded-in transparent plastic portions. The disadvantage of these constructions, in particular of the cheap construction of the LED plastic moulding-in technique which finds billions of applications, lies in the fact, in particular in the case of VCSEL diodes, that when manufactured with transparent plastics materials these components cannot be produced with sufficient optical quality and/or mechanical precision for coupling to an optical fibre. For this reason only the expensive TO housings with inset optical window cap have been used up to now.
A further difficulty with regard to the required miniaturisation results from the necessity when operating some optoelectronic components to incorporate a sensor or detector monitoring the operation or adjustment of the component in the housing of the optoelectronic component. According to the prior art, as shown in EP 0 786 836 A2, this is effected by the complex installation e.g. of monitor diodes in the TO housing used. This construction is very complex with regard both to the housing materials used and to the manufacturing steps, and thus is cost-intensive. However, for manufacturing reasons, the less expensive construction by the plastic moulding-in technique permits only limited incorporation of additional monitoring functions by additional elements. A further major disadvantage of the plastic moulding-in technique is that, when used with fibre optics, the stability of the structures and materials used for the plastic housing body is insufficient for precise coupling of the connected fibres. Plastic housing bodies can therefore be used for secure coupling only up to a maximum glass fibre diameter of 50 &mgr;m, and in particular cannot be used for single-mode fibres.
A further problem with optically emitting components is power loss in light generation. The heat arising in such components reduces the optical conductivity, sometimes substantially, by heating up the active light emitting zones.
Known from DE 195 27 026 A1 is an optoelectronic component which has a radiation emitting and/or receiving semiconductor element as the light emitting or receiving element. The semiconductor element is fixed to a carrier plate which rests on a base plate with an opening. The radiation emitted from the semiconductor element can pass out through the carrier platet and the opening in the base plate. To focus the radiation emitted by the semiconductor element the carrier plate has a lens configuration in the area of the opening in the base plate.
Known from Patent Abstracts of Japan, E-1290, 1992, Vol. 16/No. 542, JP 4-207079 A is a layer construction on a substrate in which a photodiode is formed to detect the light emitted to the layer construction.
Further known from U.S. Pat. No. 4,967,241 is a layer construction on a substrate in which a funnel-shaped passage is formed for the light emitted by the layer construction. A photodiode is formed in the substrate to detect the light emitted from the layer construction.
Finally, Patent Abstracts of Japan, E-712, 1989, Vol. 13/No. 51, JP 63-244781 A discloses a tubular housing with a funnel-shaped opening behind which a light emitting element is mounted. The light emitted by the light emitting element is focused by a spherical lens arranged in the funnel-shaped opening.
BRIEF SUMMARY OF THE INVENTION
It is the object of the invention to make available an optoelectronic component which can be manufactured at low cost and with the necessary optical qualities, and which reduces the heat generated in the element through energy dissipation and ensures good optical imaging or coupling out of the light.
This object is achieved with regard to the device and with regard to the method according to the claimed invention.
According to the invention an auxiliary carrier which is transparent at least in some areas or is at least translucent and is made of heat conductive material is provided, and firstly is connected to the system carrier and secondly is thermally coupled to the element. The feature “transparent in some areas or at least translucent” means that either the material of the auxiliary carrier itself is transparent or an opening or at least a recess allowing the passage of light is provided.
The invention further proposes to provide an auxiliary carrier for the light emitting or receiving element, which carrier ensures optimal thermal conduction in particular to the system carrier—while being of very small dimensions—and at the same time does not obstruct the inward or outward passage of light or ensures a targeted emission of light. A further advantage resulting from this feature is that the mounting of the element connected to the auxiliary carrier on the system carrier is substantially simplified since the dimensions of the system carrier are larger than those of the element alone and the auxiliary carrier is less sensitive when manipulated.
Following the principle of the invention a recess through which light passes is provided in the auxiliary carrier. Through said recess light rays for which the material of the auxiliary carrier is insufficiently transparent or is completely non-translucent can also penetrate the auxiliary carrier. To this end the recess is covered by a thin, light-permeable covering layer formed from said auxiliary carrier. The thickness of the light-absorbent material through which the light must pass is thereby reduced to a minimum. It is possible to form a sensor through which light is to pass in the relatively thin covering layer.
According to a preferred embodiment of the invention the auxiliary carrier is mechanically connected to the element in a planar fashion. Good heat dissipation from the element into the auxiliary carrier and a secure connection are thereby ensured. The auxiliary carrier is advantageously connected electrically to the element by means of an electrical bonding, facilitating current supply and signal conductance.
According to a further advantageous and therefore preferred embodiment of the invention a light-sensitive sensor is formed on or in the auxiliary carrier. Likewise, according to another advantageous embodiment of the invention a light-sensitive sensor is formed on or in the element. The advantage of this arrangement is that a sensor no longer need
Althaus Hans-Ludwig
Gramann Wolfgang
Kuhn Gerhard
Corless Peter F.
Edwards & Angell LLP
Infineon - Technologies AG
Jensen Steven M.
Tran Minhloan
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