EP0067706A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Optical transducer
Assignee: Olivetti SpA
•
Filing: 1982-06-15
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Granted: —
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Expires: 2002-06-15
Abstract
Abstract An optical transducer for detecting the angular position of a rotary member with respect to a fixed structure comprises a disc 13 mounted rotatably within a casing. The disc is provided with a plurality of opaque radial regions 19 which are spaced by transparent regions 18 which transmit the light emitted by a light source mounted on the casing. The light is received by a photodetector element 25 comprising a support plate 28 on which is disposed a multiplicity of photovoltaic cells 26 each having an area which is fraction of the area of each transparent region of the disc. The cells are subdivided into three groups A, B and C with different functions and phase positions and are distributed diffusely over the area encountered by the beam of light from the light source. The cells of each group are connected together in parallel to generate three electrical signals, one of which provides pilot control for the feed to the light source to stabilise the signals of the other two groups of photoelectric cells.
Inventors
- 👤 Ugo Carena
- 👤 Marcello Boella
- 👤 Paolo Rivera
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 21:51
CPC Classifications
G; G01; G01D; G01D5/00; G01D5/26; G01D5/32; G01D5/34; G01D5/347; G01D5/3473
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
127 words
An optical transducer for detecting the position of a movable member with respect to a fixed structure comprising a light source, a photodetector and a shutter member provided with a plurality of interruption regions for interrupting the light, spaced by transmission regions which selectively transmit the light emitted by the light source to the photodetector in response to the movement of the member, characterised in that the photodetector comprises a multiplicity of sensitive elements (26) each having an area which is a fraction of the area of each of the transmission regions (18) and in that the sensitive elements are distributed diffusely over the area encountered by the light beam generated by the light source (22), which passes through the transmission regions of the shutter member (13,50).
Claim 2
Dependent Claim
127 words
An optical transducer for detecting the position of a movable member with respect to a fixed structure comprising a light source, a photodetector and a shutter member provided with a plurality of interruption regions for interrupting the light, spaced by transmission regions which selectively transmit the light emitted by the light source to the photodetector in response to the movement of the member, characterised in that the photodetector comprises a multiplicity of sensitive elements (26) each having an area which is a fraction of the area of each of the transmission regions (18) and in that the sensitive elements are distributed diffusely over the area encountered by the light beam generated by the light source (22), which passes through the transmission regions of the shutter member (13,50).
Claim 3
Dependent Claim
51 words
An optical transducer according to claim 1, characterised in that the sensitive elements (26A or 26B or 26C) are electrically connected together to generate a single electrical signal corresponding to the amount of light detected by the multiplicity of elements on passing through the transparent regions of the shutter member (13,50).
Claim 4
Dependent Claim
39 words
An optical transducer according to-claim 2,-- characterised in that the sensitive elements (26A or 26B or 26C) are connected in parallel and in that the said signal is the sum of the output signals of each of the elements.
Claim 5
Dependent Claim
63 words
An optical transducer according to claim 1, characterised.in that the sensitive elements (26) are divided into at least two groups (26A, 26B, 26C) wherein the elements of one group are mutually disposed in such a way as to be in a first phase relationship with the transmission regions, which is different from the phase relationship of the sensitive elements of the other group.
Claim 6
Dependent Claim
36 words
An optical transducer according to claim 4, characterised in that the sensitive elements of each group (26A, 26B) are electrically connected together to generate signals which are angularly ou- of phase with respect to each other.
Claim 7
Dependent Claim
64 words
An optical transducer according to claim 4 or 5, characterised in that individual photodetector elements of a third group (26C) of the elements are interspersed between the elements of the first and second groups (26A, 26B) and are mutually phase-shifted in such a way that the sum of the areas thereof which are illuminated by the light passing through the transparent regions is constant.
Claim 8
Dependent Claim
57 words
An optical transducer according to claim 6, characterised in that the photodetector elements of the third group (26C) are electrically connected together to generate a signal which is indicative of the amount of light emitted by the light source and which is capable of providing pilot control for the electrical power supply, to stabilise the said signal.
Claim 9
Dependent Claim
177 words
An optical transducer for detecting the position of a movable member with respect to a fixed structure, comprising a light source, a position photodetector and a shutter member provided with a plurality of interruption regions for interrupting the light spaced by transmission regions which selectively transmit the light emitted by the light source to the position photodetector with a phase which is variable in dependence on the movement of the movable member, to provide a signal indicating the position of the member, characterised by a series of control photosensitive elements (26C) which are disposed in the immediate vicinities of the position photodetector (26A,B) and which are distributed diffusely in the area encountered by the light beam issuing from the transmission regions of the shutter member (13,50), and in that the control photosensitive element have phase relationships which are individually different with respect to the transmission regions and are connected together in such a way as to generate a stabilisation signal for the light source (22) which signal is substantially independent of the position of the movable member.
Claim 10
Dependent Claim
177 words
An optical transducer for detecting the position of a movable member with respect to a fixed structure, comprising a light source, a position photodetector and a shutter member provided with a plurality of interruption regions for interrupting the light spaced by transmission regions which selectively transmit the light emitted by the light source to the position photodetector with a phase which is variable in dependence on the movement of the movable member, to provide a signal indicating the position of the member, characterised by a series of control photosensitive elements (26C) which are disposed in the immediate vicinities of the position photodetector (26A,B) and which are distributed diffusely in the area encountered by the light beam issuing from the transmission regions of the shutter member (13,50), and in that the control photosensitive element have phase relationships which are individually different with respect to the transmission regions and are connected together in such a way as to generate a stabilisation signal for the light source (22) which signal is substantially independent of the position of the movable member.
Claim 11
Dependent Claim
54 words
A transducer according to claim 8, characterised in that the said elements (26C) are disposed in such a way that the active area thereof which is illuminated by the light issuing from the transmission regions is substantially independent of the position of the shutter member (13,50) with respect to the light source (22). -
Claim 12
Dependent Claim
71 words
A transducer according to any of the preceding claims, in particular for a movable member of rotary type, characterised in that the shutter member comprises a disc (13) mounted rotatably within a casing (11), in that the light interruption regions are formed by opaque sectors of the disc and the transmission regions are formed by transparent sectors which transmit the light from the light source to the photodetector or photodetectors (26).
Claim 13
Dependent Claim
58 words
An optical transducer according to claim 10, characterised in that the sensitive elements (26) are disposed on a plane which is parallel to that in which the opaque sectors and the transparent sectors are disposed, and are arranged in a plurality of rows which are substantially concentric with respect to the axis of rotation of the disc (13).
Claim 14
Dependent Claim
32 words
An optical transducer according to any of the preceding claims characterised in that the photodetector or photodetectors and the said sensitive elements comprise photovoltaic cells (26) carried by a single substrate (23).
Claim 15
Dependent Claim
136 words
An optical transducer for detecting the annular position of a rotary member with respect to a fixed structure, comprising a disc mounted rotatably within acasing and provided with a plurality of opaque radial regions spaced by transparent regions which transmit the light emitted by a light source and means for detecting the passage of the light through the transparent regions, characterised in that the detecting means comprise a multiplicity of photodetector elements (26), each having an area which is a fraction of the area of each of the transparent regions (18), and in that the said elements (26) are distributed diffusely in the area encountered by the light beam generated by the light source (22), and are connected together to generate a signal capable of providing pilot control of the electrical power-supply of the light source.
Claim 16
Dependent Claim
136 words
An optical transducer for detecting the annular position of a rotary member with respect to a fixed structure, comprising a disc mounted rotatably within acasing and provided with a plurality of opaque radial regions spaced by transparent regions which transmit the light emitted by a light source and means for detecting the passage of the light through the transparent regions, characterised in that the detecting means comprise a multiplicity of photodetector elements (26), each having an area which is a fraction of the area of each of the transparent regions (18), and in that the said elements (26) are distributed diffusely in the area encountered by the light beam generated by the light source (22), and are connected together to generate a signal capable of providing pilot control of the electrical power-supply of the light source.
Claim 17
Dependent Claim
60 words
An optical transducer according to claim 11, characterised in that the said elements (26C) are disposed in such a way that the sum of the areas thereof which are illuminated by the light passing through the transparent regions (18) is constant, whereby the amplitude of the signal is directly proportional to the amount of light emitted by the light source.
Claim 18
Dependent Claim
77 words
An optical transducer for detecting the angular position of a rotary member with respect to a fixed structure, comprising a shutter disc of transparent material, having two faces which are parallel to each other, and a plurality of radial shutter elements which are spaced by elements which transmit the light, characterised in that said .shutter elements are formed by V-shaped elements (54) provided on one of said faces and capable of totally deflecting the light incident thereon.
Claim 19
Dependent Claim
77 words
An optical transducer for detecting the angular position of a rotary member with respect to a fixed structure, comprising a shutter disc of transparent material, having two faces which are parallel to each other, and a plurality of radial shutter elements which are spaced by elements which transmit the light, characterised in that said .shutter elements are formed by V-shaped elements (54) provided on one of said faces and capable of totally deflecting the light incident thereon.
Claim 20
Dependent Claim
15 words
An-optical transducer according to claim 15, characterised in that the V-shaped elements (54) are recesses.
Claim 21
Dependent Claim
29 words
A disc according to claim 16, characterised in that the transparent material is plastics and in that the recesses (54) are formed during the operation of moulding the disc.
Claim 22
Dependent Claim
30 words
A disc according to claim 15, 16 or 17, characterised in that the angle at the apex formed by the inside surfaces of each V-shaped element is less than 105°.
Claim 23
Dependent Claim
31 words
A disc according to claim 15, 16, 17 or 18, characterised in that the faces of the disc and the surfaces of each V-shaped elements (54) are perfectly transparent and clear.
References Cited (Backward Citations)
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