Light sensitive superlattice detector arrangement with spectral sensitivity

• US 4,847,489 A
• Filed: 03/30/1988
• Issued: 07/11/1989
• Est. Priority Date: 04/01/1987
• Status: Expired due to Fees

• Current Assignee: Messerschmitt-Bolkow-Blohm GmbH
• Original Assignee: Messerschmitt-Bolkow-Blohm GmbH
• Inventors: Dietrich, Klaus
• Primary Examiner(s): Nelms, David C.
• Assistant Examiner(s): Messinger, Michael
• Application Number:
  US07/175,107
• Time in Patent Office: 468 Days
• Field of Search: 250/226, 250/578, 357/30 H, 357/30 E, 357/30 L, 357/4, 357/45, 358/44, 358/48
• US Class Current: 250/226
• CPC Class Codes: H01L 27/14609 Pixel-elements with integrated switching, control, storage or amplification elements scanning details of imagers (circuitry of solid-state image sensors H04N25/00); circuitry of imagers H04N25/70
• CPC Class Codes: H01L 27/14667 Colour imagers

Abstract

A light sensitive detector arrangement contains a plurality of photosensitive detector elements, which in each instance have a multilayer structure of alternating positively and negatively doped photosensitive semiconductor material with a superlattice structure and control electrodes arranged vertically to the semiconductor layers and bordering on them on their front faces. To these a control voltage can be applied in order to control the spectral light sensitivity. An array contains in each case a predetermined number (for example three) of photo detector groups (E₁₁ to E_mm) of photosensitive detector elements (E₁₁₁, E₁₁₂, E₁₁₃. . . respectively E _mml, E_mm2, E_mm3). The control electrodes of the photo detector elements of each photo detector group are connected to variable voltage regulators (U₁, U₂, U₃). Through the voltage regulators the upper and/or lower limit wavelength (λ_o, λ_u) of the photo detector elements of the discrete photo detector groups can be set differently and graded with respect to each other. A filter arrangement is provided having high pass or low pass function, the filter edge (λ _F) of which subdivides the spectral range of the discrete photo detector elements of the photo detector groups into an upper or lower effective spectral range (λ_F -λ_o3, λ_F -λ_o2, λ_F -λ_ol). Differential amplifiers can be driven with the signals of the photo detector elements of each photo detector group, the inputs of which can be driven by the spectral signals of the outputs of two adjacent photo detector elements, such that at the outputs of the differential amplifiers differentiable selected spectral signal responses occur.

Claims

1. A light sensitive detector arrangement having a plurality of photosensitive detector elements, each detector element having a multilayer structure of alternating positively and negatively doped photosensitive semiconductor material with a superlattice structure and having control electrodes arranged vertically with respect to the semiconductor layers and bordering on the semiconductor layers on front faces thereof, the control electrodes being adapted to receive a control voltage in order to control the spectral light sensitivity of the detector arrangement, an array of a predetermined number of the photo detector groups having photosensitive detector elements being provided, the control electrodes of the photo detector elements of each photo detector group being connected to variable voltage regulators, at least one of upper and lower limit wavelengths of the photo detector elements of the discrete photo detector groups being set differently via the voltage regulators and being graded with respect to each other, a filter arrangement having a high pass and low pass function being provided upstream of the array of the photo detector groups, the filter arrangement having a filter edge which divides the spectral range of the discrete photo detector elements of the photo detector groups into an upper or lower effective spectral range, differential amplifiers being driven by the signals of the photo detector elements of each photo detector group, inputs of the differential amplifiers being driven by spectral signals of outputs of two adjacent photo detector elements, such that at outputs of the differential amplifiers, differentiable selected spectral signal responses occur.

2. The light sensitive detector arrangement recited in claim 1, wherein control voltages for the photo detector elements of each photo detector group are selected and signal output voltages of the differential amplifiers and in processing stages influenced such that the spectral signal responses border on each other.

3. The light sensitive detector arrangement recited in claim 1, wherein the control voltages are supplied to the photo detector elements across a drive circuit.

4. The light sensitive detector arrangement recited in claim 1, wherein an output signal of the photo detector element with a spectral signal response whose maximum limit wavelength is most closely adjacent to the filter edge wavelength is evaluated without formation of difference.

5. The light sensitive detector arrangement recited in claim 1, further comprising an addressable semiconductor storage means associated with the array of the photo detector groups, said storage means being operationally connected to a microcomputer.

6. The light sensitive detector arrangement recited in claim 5 wherein the storage means comprises a read and write storage means.

7. The light sensitive detector arrangement recited in claim 6, wherein the drive circuit comprises a multiplexer by which all photo detector elements of the array are sequentially drivable by each of the discrete control voltages and simultaneously the light-dependent output signals are storable in the read and write storage means, the differential amplifier being connected downstream from the read and write storage means.