EP0523784A1
Expired / Lapsed
EP
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An image detector and a method of manufacturing such an image detector
Assignee: Philips Electronics UK Ltd
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Filing: 1992-07-07
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Granted: —
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Expires: 2012-07-07
Abstract
Abstract An image detector (100) has a substrate (1) carrying a series of layers of different materials patterned to define an array (2) of photosensitive elements (20) each having first (21) and second (22) opposed electrodes with the first electrode (21) being closer to the substrate (1) than the second electrode (22) and a plurality of switching elements (30), each switching element having first (31) and second (32) main electrodes and a control (33) electrode with the second main electrode (32) of each switching element 30 being connected to the second electrode (22) of an associated one of the photosensitive elements (20) and the first electrodes (21) of the photosensitive elements (20) being connected a common line (40). Each photosensitive element (20) has a first electrode (21) which is larger in area than its second electrode (22) so that the first electrode (21) extends laterally beyond the periphery (22a) of the second electrode (22) and the first electrode (21) of each photosensitive element (20) is formed from the same layer as one of the electrodes (31 or 33) of the associated switching element (30). This enables the number of required metallisation levels to be reduced and enables a detector to be provided which is easily electrically testable and has reduced parasitic capacitances and a reduced sensitivity to direct illumination.
Inventors
- 👤 Martin John c/o Philips Research Lab. Powell
- 👤 Ian Douglas C/O Philips Research Lab. French
- 👤 John Richard c/o Philips Research Lab. Hughes
- 👤 Neil Christopher c/o Philips Research Lab. Bird
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 06:44
CPC Classifications
H; H10; H10F; H10F39/00; H10F39/10; H10F39/12; H10F39/18
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
157 words
An image detector comprising a substrate carrying a series of layers of different materials patterned to define an array of photosensitive elements each having first and second opposed electrodes with the first electrode being closer to the substrate than the second electrode and a plurality of switching elements, each switching element having first and second main electrodes and a control electrode with the second main electrode of each switching element being connected to the second electrode of an associated one of the photosensitive elements and the first electrodes of the photosensitive elements being connected to a common line, characterised in that each photosensitive element has a first electrode which is larger in area than its second electrode so that the first electrode extends laterally beyond the periphery of the second electrode and in that the first electrode of each photosensitive element is formed from the same layer as one of the electrodes of the associated switching element.
Claim 2
Dependent Claim
77 words
An image detector according to Claim 1, further characterised in that the photosensitive elements are arranged in a regular matrix of rows and columns of photosensitive elements, in that the control electrodes of the switching elements associated with a row of photosensitive elements are connected together to a respective row electrode and in that the first main electrodes of the switching elements associated with a column of photosensitive elements are connected together to a respective column electrode.
Claim 3
Dependent Claim
35 words
An image detector according to Claim 1 or 2, further characterised in that the first electrodes of the photosensitive elements are formed from the same layer as the first main electrodes of the switching elements.
Claim 4
Dependent Claim
34 words
An image detector according to Claim 1 or 2, further characterised in that the first electrodes of the photosensitive elements are formed from the same layer as the control electrodes of the switching elements.
Claim 5
Dependent Claim
24 words
An image detector according to Claim 1,2,3 or 4, further characterised in that the control electrodes are formed by a layer adjacent the substrate.
Claim 6
Dependent Claim
28 words
An image detector according to any one of the preceding claims, further characterised in that the switching elements comprise thin-film transistors and the photosensitive elements comprise photosensitive diodes.
Claim 7
Dependent Claim
45 words
An image detector according to any one of the preceding claims, further characterised in that an energy conversion layer is provided for converting electromagnetic radiation with a first range of wavelengths into electromagnetic radiation with a second range of wavelengths detectable by the photosensitive elements.
Claim 8
Dependent Claim
19 words
An image detector according to Claim 7, further characterised in that the energy conversion layer comprises a phosphor layer.
Claim 9
Dependent Claim
48 words
An image detector according to Claim 7 or 8, further characterised in that the energy conversion layer is provided on a protective insulating layer provided over the photosensitive and switching elements, the protective insulating layer being at least partially transparent to electromagnetic radiation detectable by the photosensitive elements.
Claim 10
Dependent Claim
84 words
An image detector according to any one of Claims 1 to 6, further characterised in that a protective layer is provided on the substrate to cover the array of photosensitive elements and associated switching elements, the substrate and the protective layer being at least partially transparent to electromagnetic radiation detectable by the photosensitive elements for enabling the photosensitive elements to detect electromagnetic radiation which has passed through the substrate and been reflected onto the photosensitive elements by an object placed on the protective layer.
Claim 11
Dependent Claim
29 words
An image detector according to Claim 10, further characterised in that the protective layer comprises a material selected from the group consisting of polyimide, silicon dioxide and silicon nitride.
Claim 12
Independent Claim
159 words
A method of manufacturing an image detector, which method comprises providing a series of layers of different materials on a substrate and patterning the layers to define an array of photosensitive elements each having first and second opposed electrodes with the first electrode being closer to the substrate and a plurality of switching elements, each switching element having first and second main electrodes and a control electrode with the second main electrode of each switching element being connected to the second electrode of an associated one of the photosensitive elements and the first electrodes of the photosensitive elements being connected to a common line, characterised by forming the first electrode of each photosensitive element to be larger in area than its second electrode so that the first electrode extends laterally beyond the periphery of the second electrode and forming the first electrode of each photosensitive from the same layer as one of the electrodes of the associated switching element.
Claim 13
Dependent Claim
29 words
A method according to Claim 12, further characterised by forming the first electrodes of the photosensitive elements from the same layer as the first electrodes of the switching elements.
Claim 14
Dependent Claim
153 words
A method according to Claim 13, further characterised by providing a first conductive layer on the substrate and patterning the first conductive layer to define the control electrodes, providing at least one semiconductor layer on the first conductive layer, providing a second conductive layer over the semiconductor layer and patterning the semiconductor layer and the second conductive layer to define active device regions of the switching elements and the first and second electrodes of the switching elements and the first electrodes of the photosensitive elements, providing at least one further semiconductor layer over the second conductive layer and patterning the further semiconductor layer to define active regions of the photosensitive elements, providing an isolating insulative layer over the further semiconductor layer, patterning the insulating layer to define contact windows and providing a third conductive layer connect the second electrode of each photosensitive element to the second main electrode of the associated switching element.
Claim 15
Dependent Claim
28 words
A method according to Claim 12, further characterisedby forming the first electrodes of the photosensitive elements from the same layer as the control electrodes of the switching elements.
Claim 16
Dependent Claim
120 words
A method according to Claim 15, further characterised by providing a first conductive layer on the substrate and patterning the first conductive layer to define the control electrodes of the transistors and the first electrodes of the photosensitive elements, providing at least one semiconductor layer on the first conductive layer and patterning the semiconductor layer to define active device regions of the switching elements and of the photosensitive elements, providing at least one further conductive layer over the semiconductor layer and patterning the at least one further conductive layer to define the first and second electrodes of the switching elements and to connect the second electrode of each photosensitive element to the second main electrode of the associated switching element.
Claim 17
Independent Claim
49 words
A method according to any one of Claims 12 to 16, further characterised by providing an energy conversion layer over the structure on the substrate for converting electromagnetic radiation with a first range of wavelengths into electromagnetic radiation with a second range of wavelengths detectable by the photosensitive element.
Claim 18
Independent Claim
81 words
A method according to any one of Claims 12 to 17, further characterised by providing a protective layer on the substrate to cover the array of photosensitive elements and associated switching elements, the substrate and the protective layer being at least partially transparent to electromagnetic radiation detectable by the photosensitive elements for enabling the photosensitive elements to detect electromagnetic radiation which has passed through the substrate and been reflected onto the photosensitive elements by an object placed on the protective layer.
Claim 19
Dependent Claim
31 words
A method according to Claim 18, further characterised by providing the protective layer as a layer of a material selected from the group consisting of polyimide, silicon dioxide and silicon nitride.
Claim 20
Dependent Claim
164 words
An image detector comprising a substrate carrying a series of layers of different materials patterned to define an array of photosensitive elements each having an active device area bounded by first and second opposed electrodes with the first electrode being closer to the substrate than the second electrode and being larger in area than the second electrode so that the first electrode extends laterally beyond the periphery of the active device area and the second electrode, and a plurality of switching elements associated with the photosensitive elements for controlling the storage by and readout of information from the photosensitive elements, a protective layer being provided on the substrate to cover the array of photosensitive elements and associated switching elements, the substrate and the protective layer being at least partially transparent to electromagnetic radiation detectable by the photosensitive elements for enabling the photosensitive elements to detect electromagnetic radiation which has passed through the substrate and been reflected from an object placed on the protective layer.
Claim 21
Dependent Claim
60 words
A method of obtaining an image of an object, which method comprises placing the object on the protective layer of an image detector in accordance with Claim 10, 11 or 20, and directing electromagnetic radiation detectable by the photosensitive elements through the substrate onto the object so that electromagnetic radiation reflected by the object is detected by the photosensitive elements.
References Cited (Backward Citations)
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