Two-color photoelectric detectors having an integral filter

• US 3,962,578 A
• Filed: 02/28/1975
• Issued: 06/08/1976
• Est. Priority Date: 02/28/1975
• Status: Expired due to Term

• Current Assignee: Loral Aerospace Corp. (MHR Holdings LLC (New York))
• Original Assignee: Aeronutronic Ford Corporation (Galileo Parent, Inc.)
• Inventors: Roschen, John
• Primary Examiner(s): La Roche, Eugene
• Application Number:
  US05/554,193
• Time in Patent Office: 466 Days
• Field of Search: 250/339, 250/211 R, 250/211 J, 250/226, 250/238, 350/311, 350/313, 350/316, 357/30
• US Class Current: 250/226
• CPC Class Codes: G01J 1/0209 Monolithic
• CPC Class Codes: G01J 1/0488 with spectral filtering
• CPC Class Codes: G01J 1/4228 arrangements with two or more detectors, e.g. for sensitivity compensation
• CPC Class Codes: G01J 5/28 using photoemissive or photovoltaic cells
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48463 the connecting portion on the bonding area of the semiconductor or solid-state body being a ball bond
• CPC Class Codes: H01L 25/043 Stacked arrangements of devices
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 31/00 Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof H10K30/00 takes precedence; devices consisting of a plurality of solid state components formed in, or on, a common substrate, other than combinations of radiation-sensitive components with one or more electric light sources, H01L27/00

Abstract

Two photoelectric detector elements, having substantially different response wavelengths, are mounted in a housing in cascade relationship. The outer element is selected to be transparent to the response wavelength of the inner element and it is provided with an integral filter that is transmissive at the response wavelength of the inner element. Anti-reflective coatings are used to minimize reflective losses.

Claims

1. In a photodetector combination constructed to sense radiant energy in a plurality of wavelength bands, said combination comprising:

a first photodetector optimized for response at a first wavelength, said first photodetector constructed to be transparent to a second wavelength that is relatively longer than said first wavelength and with active elements adjacent a first face thereof,

a second photodetector optimized for response of said second wavelength, and

means for mounting said first and said second photodetectors in a cascade wherein illumination is directed onto said first face of said first photodetector,

the improvement comprising an integral filter coating formed on a second face of said first photodetector, said second face being opposite said first face and adjacent said second photodetector, said filter coating forming a bandpass radiant energy filter intermediate said first and said second photodetectors, said bandpass being selected to fall within the radiant energy wavelength response of said second photodetector.

2. The improvement of claim 1 wherein said filter coating is controlled in thickness to act as an anti-reflective coating at said second wavelength.