Light emitting device

摘要

The light emission device useful in dental technology, comprises a first semiconductor chip (12), a second semiconductor chip (14) fitted on the first semiconductor chip, a substrate (66) on which the first semiconductor chip is fitted, and a reflector fitted below a lower semiconductor chip. The second semiconductor chip leaves free an upwardly facing area of the first semiconductor chip. The left-free area of lower and upper semiconductor chips is light emitting. Lateral light emission area of the upper semiconductor chip extends relative to lateral light emission area of the lower chip. The light emission device useful in dental technology, comprises a first semiconductor chip (12), a second semiconductor chip (14) fitted on the first semiconductor chip, a substrate (66) on which the first semiconductor chip is fitted, and a reflector fitted below the lower semiconductor chip. The second semiconductor chip leaves free an upwardly facing area of the first semiconductor chip. The left-free area of lower and upper semiconductor chips is light emitting. Lateral light emission area of the upper semiconductor chip extends relative to lateral light emission area of the lower chip in a manner shifted toward the center of the semiconductor chip. The semiconductor chips are constructed pyramidally with respect to another, are partly transmissive to emitted radiation, are connected to one another by a reflection-free adhesive layer, emit light having different spectral wavelengths, are electrically connected in series/parallel with one another, and have an electrical connection zone on their top side in the region of the left-free area. The adhesive layer has a thermal conductivity with a same magnitude as the thermal conductivity of the semiconductor chips, and a thickness of less than 50 mu m. The substrate is electrically insulating and carries a reflection layer. An electrical connection area of the lower semiconductor chip is formed by the substrate. The upper semiconductor chip is smaller than the lower semiconductor chip. Size difference of chips is twice the thickness of each semiconductor chip. The semiconductor chips are rotated relative to another at 45[deg] . The substrate has a projection with dimensions corresponding to dimensions of the lower semiconductor chip. An additional ring reflector (80) surrounds the semiconductor chips. The reflector experiences an oblique/parabolic orientation per second, and reflects the lateral light emission of the semiconductor chips towards the front. A converging lens is fitted before the semiconductor chips, and is supported on the ring reflector. A space between the semiconductor chips and the underside of the converging lens is filled by a transparent/translucent silicone gel. The electrical connection areas of the chips are connected to free areas of a printed circuit board (70) by bonding wires. The printed circuit board extends laterally alongside the semiconductor chips, and runs with conductor tracks below the ring reflector.