Solid-state color imager with two layer three story structure

• US 4,443,813 A
• Filed: 07/08/1983
• Issued: 04/17/1984
• Est. Priority Date: 12/15/1981
• Status: Expired due to Term

• Current Assignee: Fuji Photo Film Company Limited Kanagawa Japan
• Original Assignee: Fuji Photo Film Co Limited (Fujifilm Holdings Corporation)
• Inventors: Tabei, Masatoshi
• Primary Examiner(s): Chin, Tommy P.
• Application Number:
  US06/512,051
• Time in Patent Office: 284 Days
• Field of Search: 358/41, 358/43, 358/44, 358/46, 358/47, 358/48, 250/211 J
• US Class Current: 348/280
• CPC Class Codes: H01L 27/144 Devices controlled by radiation
• CPC Class Codes: H01L 27/14667 Colour imagers
• CPC Class Codes: H01L 31/09 Devices sensitive to infrared, visible or ultraviolet radiation H01L31/101 takes precedence
• CPC Class Codes: H04N 25/70 SSIS architectures; Circuits associated therewith

Abstract

A solid-state color imager comprised of a solid-state base comprised of a plurality of electrical switching elements said base further including photosensitive elements associated with some of the switching elements arranged in sets having superimposed thereon a plurality of photosensor layers which can detect and absorb different colors of light. Each photosensitive layer is comprised of an upper transparent continuous electrode sublayer, a photoconductive sublayer, and a back mosaic transparent electrode sublayer which is electrically connected to said base. When light strikes the outermost photosensitive layer, light of a particular color is absorbed, and in connection with said base, its presence is electrically detected and recorded. The unabsorbed light continues to travel and strike the next succeeding photosensor layer whereat another color of light is absorbed and detected. The unabsorbed light passing through the second photosensor layer strikes the photosensitive elements of the base which detect the remaining light. The photosensor layers are electrically insulated from each other and the base and in connection with the photosensitive elements of the base make possible detection of three separate colors of light such as blue, green and red without the use of multi-color filter arrays, although in some embodiments a monocolor filter is used.

Claims

1. A solid-state color imager, comprising:

a solid-state base comprised of an array of electrical switching elements arranged on portions of said base with a plurality of photosensitive elements associated, respectively, with a first plurality of said electrical switching elements;

a first layer of insulation material positioned over said base;

a first photosensitive layer superimposed on said first layer of insulation material, said first photosensitive layer being comprised of a top transparent electrode sublayer, a back transparent mosaic electrode sublayer, and a photoconductive sublayer positioned between said top and back sublayers, said back mosaic electrode sublayer being segmented into an array of portions corresponding to a second plurality of said electrical switching elements on said base, and said segmented portions of said back mosaic electrode sublayer being electrically connected, respectively, with said second plurality of said electrical switching elements on said base;

a second layer of insulation material positioned over said first photosensitive layer;

a second photosensitive layer superimposed over said second layer of insulation material, said second photosensitive layer being comprised of a top transparent electrode sublayer, a back transparent mosaic electrode sublayer, and a photoconductive sublayer positioned between said top and back sublayers, said back mosaic electrode being segmented into an array of portions corresponding to a third plurality of said electrical switching elements on said base, and said segmented portions of said back mosaic electrode being electrically connected, respectively, to said third plurality of said electrical switching elements on said base;

said first and second photosensitive layers being sensitive to and absorptive of different ranges of the visible wavelength spectrum, whereby electrical signals from said photosensitive layers represent light intensities of two different color ranges and wherein said photosensitive elements on said base represent light intensities of a third color range.

3. A solid-state color imager, as claimed in claim 1, wherein said photoconductive sublayers and said photosensitive elements are constructed and positioned in such a manner that each succeeding layer in the direction toward said solid-state base has an absorption versus wavelength characteristic resulting in the layer absorbing a broader band of the light spectrum.

5. A solid-state color imager, as claimed in claim 1, wherein one of said photoconductive sublayers is sensitive to and absorbs light in the blue region of the spectrum, said other one of said photoconductive sublayers is sensitive to and absorbs light at least in the green, but not the red, region of the spectrum, and said photosensitive elements of said base are sensitive to light at least in the red region of the spectrum.

7. A solid-state color imager, as claimed in claim 1, wherein said electrical switching elements arranged on said base are metal oxide semiconductor (MOS) devices.

9. A solid-state color imager, as claimed in claim 1, wherein one of said photoconductive sublayers is comprised of a photosensitive material selected from the group consisting of CdS, ZnCdS, or ZnSeTe, the other one of said photoconductive sublayers being comprised of a photosensitive material selected from the group consisting of amorphous selenium, CdSe or GaAsP.

12. A solid-state imager, as claimed in claim 1, wherein said electrical switching elements are comprised of metal nitride oxide semiconductor (MNOS) devices.

2. A solid-state color imager, comprising:

a solid-state base comprised of a plurality of electrical switching elements arranged in sets of three; and

two vertically positioned photosensitive layers superimposed on each other on said solid-state base which has photosensitive elements on a portion of its surface, each of said photosensitive layers being comprised of a top transparent electrode sublayer, a back transparent mosaic electrode sublayer and a photoconductive sublayer positioned between said top and back sublayers, each of said back mosaic sublayers being segmented into an array of portions wherein a back mosaic sublayer portion of each of said photosenstive layers is electrically connected to respective ones of said electrical switching elements from each set of three, such that vertically positioned back mosaic sublayer portions on each of said two photosensitive layers are connected to one of said electrical switching elements of each set of three with said photosensitive elements of said base also being associated with respective ones of said electrical switching elements of each set of three, thus forming an array of pixel sets, said photosensitive layers and said photosensitive elements of said base each being sensitive to and absorptive of different ranges of the visible wavelength spectrum, whereby electrical signals received from each of said photosensitive layers and said photosensitive elements of said base represent light intensities of three different color ranges.

4. A solid-state color imager, as claimed in claim 2, wherein said photoconductive sublayers and said photosensitive elements are constructed and positioned in such a manner that each succeeding layer in the direction toward said solid-state base has an absorption versus wavelength characteristic resulting in the layer absorbing a broader band of the light spectrum.

6. A solid-state color imager, as claimed in claim 2, wherein said photoconductive sublayers are comprised of an outermost layer furthest from said solid-state base which is sensitive to and absorbs light in the blue region of the spectrum, a layer which is sensitive to and absorbs light in at least the green, but not the red, region of the spectrum, with said photosensitive elements of said solid-state base being sensitive to light at least in the red region of the spectrum.

8. A solid-state color imager, as claimed in claim 2, wherein said electrical switching elements arranged on said base are metal oxide semiconductor (MOS) devices.

11. A solid-state imager as claimed in claim 8, wherein each of said first and second plurality of photoconductors comprises, a layer of photoconductor material having top and bottom electrodes said bottom electrode being segmented to define the individual photoconductors of said first and second plurality of photoconductors.

13. A solid-state imager, as claimed in claim 2, wherein said electrical switching elements are comprised of metal nitride oxide semiconductor (MNOS) devices.

10. A solid-state imager comprising:

a semiconductor switching matrix comprising a matrix of charge switching elements, a first plurality of said charge switching elements having an equal plurality of photodiodes associated therewith;

a first plurality of photoconductors responsive to and absorptive of light in a relatively low band of the visible spectrum, said first plurality of photoconductors being electrically connected, respectively, to a second plurality of said charge switching elements to deliver to said charge switching elements electrical signals representing the intensity of light which impinges thereon and to which said first plurality of photoconductors are sensitive;

a second plurality of photoconductors responsive to and absorptive of light in at least a higher band than said first plurality of photoconductors, said second plurality of photoconductors being electrically connected, respectively, to a third plurality of said charge switching elements to deliver to said charge switching elements electrical signals representing the intensity of light which impinges thereon and to which said second plurality of photoconductors are sensitive;

said first plurality of photoconductors, said second plurality of photoconductors, and said semiconductor switching matrix constituting three superimposed layers of said imager, superimposed in an arrangement such that light impinging on said solid-state imager falls first on said first plurality of photoconductors, the wavelengths of said light not absorbed thereby falls on said second plurality of photoconductors, and the wavelengths of light not absorbed thereby falling on said photodiodes, whereby the signals switched by said first, second and third pluralities of charge switching elements represent, respectively, light intensities of three different bandwidths.