Browse Prior Art Database

Image Converter With Built In Gain

IP.com Disclosure Number: IPCOM000079659D
Original Publication Date: 1973-Aug-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 2 page(s) / 41K

Publishing Venue

IBM

Related People

Lanza, G: AUTHOR [+2]

Abstract

The described converter, as shown in Fig. 1, basically involves an integrated structure that combines an infrared sensitive phototransistor with a visible electroluminescent (EL) diode. The device operates to convert infrared light to visible 1.8 eV.

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Image Converter With Built In Gain

The described converter, as shown in Fig. 1, basically involves an integrated structure that combines an infrared sensitive phototransistor with a visible electroluminescent (EL) diode. The device operates to convert infrared light to visible 1.8 eV.

As shown in FIG. 1, in exaggerated scale, the device consists of six regions. These regions would typically have the characteristics as follows:

(Image Omitted)

Typical overall physical dimensions for the device involve a semiconductor wafer about 0.5cm in diameter and 2 mils in thickness, mounted between glass substrates. Bias may be provided by a 6 volt battery connected to ohmic ring contacts. Fig. 2 shows an energy band diagram for zero bias, and Fig. 3 shows the energy bands under operating bias.

In operation, an infrared image is focused onto junction J1 through the transparent material of region 1, as shown approaching the left face in Fig. 1. A red image may be viewed with an eyepiece, for example, at the opposite face. Photon absorption at J1 produces hole-electron pairs in region 2. Regions 1, 2 and 3 act as the emitter, base and collector, respectively, of a phototransistor arrangement. As shown in the band diagram, the holes generated in region 2 by the photons are contained by the high-potential well. This causes a further lowering of the forward biased emitter-base heterojunction barrier so that for each photon absorbed by the base, g electrons are injected into the ba...