Abstract: A high density array of light emitting diodes for visual display and imaging purposes. The array is mounted on a thermally and electrically conducting medium such as an aluminum block. The block, in one embodiment, is configured to permit a supplementary cooling liquid to be circulated through it. Typically, such LED arrays are fabricated by forming a plurality of p-type islands in n-type host semiconductor material. Each p-type island has an individually addressable contact and a common n-type contact is made to the aluminum block by, for example an electrically conductive epoxy. In operation the connection between the carrier and array may be lost due to a temperature differential between the two components. The present invention avoids this problem by providing a separate connection in parallel with or in place of the common n-type contact.

Abstract: A method of fabricating high resolution, light emitting devices for printheads and the like is disclosed. An epitaxial layer of an alloy compound such as GaAs:P is used as the host material. Typically, p-type material is diffused into n-type material to form planar and isolated p-n junctions that provide individual light emitting pixels. In the method of this invention the shape of each pixel and the gap between pixels is controlled by tailoring the dimensions of the aperture through which thermal diffusion takes place and by providing a layer of modulation material over the diffusion aperture. This combination results in the control of lateral diffusion parameters such that both the shape of the pixels and the gap between can be controlled.