Optical transducer and focusing system

Claim 2

A lens focusing system, comprising: source means for producing a beam of radiation to be focused on and reflected from a surface; a lens; focusing means for moving said lens to focus said beam of radiation on the surface; transducer means, disposed in the path of the reflected radiation, said transducer means including a first detector having a radiation-sensitive surface adapted to receive a first portion of said reflected radiation, said first detector developing a first electrical signal indicative of the radiation received thereon, and said transducer means further including a second detector, electrically isolated from said first detector, having a radiation-sensitive surface at least a portion of which is disposed around the periphery of said radiation-sensitive surface of said first detector and adapted to receive a second portion of said reflected radiation, said second detector developing a second electrical signal indicative of the radiation received thereon; and control means, responsive to said transducer means, for comparing said first signal with said second signal and controlling said focusing means to move said lens as a function of the difference between said first and second signals.

Claim 3

A lens focusing system as defined in claim 1, wherein said radiation-sensitive surface of said first detector and said radiation-sensitive surface of said second detector are substantially coplanar.

Claim 4

A lens focusing system as defined in claim 2, wherein said radiation-sensitive surface of said first detector is circular in shape.

Claim 5

A lens focusing system as defined in claim 3, wherein said radiation-sensitive surface of said second detector is annular in shape.

Claim 6

A lens focusing system as defined in claim 1, wherein said radiation-sensitive surface of said first detector and said radiation-sensitive surface of said second detector are formed on a common substrate.

Claim 7

A lens focusing system for use in an apparatus for reading information carried by an information bearing surface, said system comprising: source means for producing a source beam of radiation to be focused on the information bearing surface, at least a portion of said source beam being reflected from the surface and modulated by the information carried thereby; optical system means for directing said source beam along a first optical path from said source means to the information bearing surface and for focusing the reflected beam of radiation at an image plane along a second optical path removed from the information bearing surface, said optical system means including a lens, movable along said first optical path, to focus said source beam on the information bearing surface; transducer means, disposed in said second optical path, non-coincidental with said image plane of said reflected beam, for receiving said reflected beam, said transducer means including a first detector having a radiation-sensitive surface adapted to receive a first portion of said reflected beam, said first detector developing a first electrical signal indicative of the radiation received thereon, and said transducer means further including a second detector, electrically isolated from said first detector, having a radiation-sensitive surface at least a portion of which is disposed around the periphery of said radiation-sensitive surface of said first detector and adapted to receive a second portion of said reflected beam, said second detector developing a second electrical signal indicative of the radiation received thereon; control means, responsive to said transducer means, for comparing said first signal with said second signal; and means, responsive to said control means, for moving said lens along said first path to focus said source beam on the information bearing surface.

Claim 8

A lens focusing system for use in an apparatus for reading information carried by an information bearing surface, said system comprising: source means for producing a source beam of radiation to be focused on the information bearing surface, at least a portion of said source beam being reflected from the surface and modulated by the information carried thereby; optical system means for directing said source beam along a first optical path from said source means to the information bearing surface and for focusing the reflected beam of radiation at an image plane along a second optical path removed from the information bearing surface, said optical system means including a lens, movable along said first optical path, to focus said source beam on the information bearing surface; transducer means, disposed in said second optical path, non-coincidental with said image plane of said reflected beam, for receiving said reflected beam, said transducer means including a first detector having a radiation-sensitive surface adapted to receive a first portion of said reflected beam, said first detector developing a first electrical signal indicative of the radiation received thereon, and said transducer means further including a second detector, electrically isolated from said first detector, having a radiation-sensitive surface at least a portion of which is disposed around the periphery of said radiation-sensitive surface of said first detector and adapted to receive a second portion of said reflected beam, said second detector developing a second electrical signal indicative of the radiation received thereon; control means, responsive to said transducer means, for comparing said first signal with said second signal; and means, responsive to said control means, for moving said lens along said first path to focus said source beam on the information bearing surface.

Claim 9

A lens focusing system as defined in claim 6, and further including: means, responsive to said transducer means, for combining said first signal and said second signal to derive the information contained in said reflected beam.

Claim 10

A lens focusing system as defined in claim 6, wherein said radiation-sensitive surface of said first detector and said radiation-sensitive surface of said second detector are substantially coplanar.

Claim 11

A lens focusing system as defined in claim 6, wherein said first detector and said second detector are formed on a common substrate.

Claim 12

A lens focusing system as defined in claim 6, wherein said radiation-sensitive surface of said first detector is centered substantially on an axis defined by said reflected beam.

Claim 13

A lens focusing system as defined in claim 10, wherein said radiation-sensitive surface of said second detector is substantially concentric with said radiation-sensitive surface of said first detector.

Claim 14

A lens focusing system as defined in claim 6, wherein said radiation-sensitive surface of said second detector has an area substantially 25 times or more greater than the area of said radiation sensitive surface of said first detector.

Claim 15

A lens focusing system as defined in claim 6, wherein the said radiation-sensitive surface of said first detector receives radiation in a prescribed ratio to the radiation received on said radiation-sensitive surface of said second detector, when said source beam is in optimum focus on the information bearing surface.

Claim 16

A lens focusing system as defined in claim 13, wherein said ratio is substantially 1:1.

Claim 17

A lens focusing system as defined in claim 6, and further including: auxiliary lens means, disposed in said second optical path substantially at said image plane when said source bean is in optimum focus on the information bearing surface, for refracting said reflected beam only when said source beam is out of focus.

Claim 18

A lens focusing system as defined in claim 15, wherein said auxiliary lens means is centered substantially on an axis defined by said reflected beam.

Claim 19

A lens focusing system for use in an apparatus for reading information carried by an information bearing surface, said system comprising: source means for producing a source beam of radiation to be focused on the information bearing surface, at least a portion of said source beam being reflected from the surface and modulated by the information carried thereby; optical system means for directing said source beam along a first optical path from said source means to the information bearing surface and for focusing the reflected beam of radiation at an image plane along a second optical path removed from the information bearing surface, said optical system means including a lens, movable along said first optical path, to focus said source beam on the information bearing surface; transducer means, disposed in said second optical path, non-coincidental with said image plane of said reflected beam, for receiving said reflected beam, said transducer means including a first detector having a closed boundary defining a radiation-sensitive-surface of predetermined area disposed on an axis defined by said reflected beam, whereby said radiation-sensitive surface is adapted to receive a first portion of said reflected beam, said first detector developing a first electrical signal indicative of the radiation received thereon, and said transducer means further including a second detector having a radiation-sensitive surface substantially surrounding, but electrically isolated from and substantially coplanar with, said radiation-sensitive surface of said first detector, whereby said radiation surface of said second detector is adapted to receive a second portion of said reflected beam, said second detector developing a second electrical signal indicative of the radiation received thereon; control means, responsive to said transducer means, for comparing said first signal with said second signal in a prescribed manner; and servo means, responsive to said control means, for moving said lens along said first path to focus said source beam on the information bearing surface.

Claim 20

A lens focusing system for use in an apparatus for reading information carried by an information bearing surface, said system comprising: source means for producing a source beam of radiation to be focused on the information bearing surface, at least a portion of said source beam being reflected from the surface and modulated by the information carried thereby; optical system means for directing said source beam along a first optical path from said source means to the information bearing surface and for focusing the reflected beam of radiation at an image plane along a second optical path removed from the information bearing surface, said optical system means including a lens, movable along said first optical path, to focus said source beam on the information bearing surface; transducer means, disposed in said second optical path, non-coincidental with said image plane of said reflected beam, for receiving said reflected beam, said transducer means including a first detector having a closed boundary defining a radiation-sensitive-surface of predetermined area disposed on an axis defined by said reflected beam, whereby said radiation-sensitive surface is adapted to receive a first portion of said reflected beam, said first detector developing a first electrical signal indicative of the radiation received thereon, and said transducer means further including a second detector having a radiation-sensitive surface substantially surrounding, but electrically isolated from and substantially coplanar with, said radiation-sensitive surface of said first detector, whereby said radiation surface of said second detector is adapted to receive a second portion of said reflected beam, said second detector developing a second electrical signal indicative of the radiation received thereon; control means, responsive to said transducer means, for comparing said first signal with said second signal in a prescribed manner; and servo means, responsive to said control means, for moving said lens along said first path to focus said source beam on the information bearing surface.

Claim 21

A lens focusing system as defined in claim 17, and further including: means, responsive to said transducer means, for combining said first signal and said second signal to derive the information contained in said reflected beam.

Claim 22

A lens focusing system as defined in claim 18, wherein said combing means combines said first signal and said second signal additively.

Claim 23

A lens focusing system as defined in claim 19, wherein said control means compares said first signal with said second signal differentially.

Claim 24

A lens focusing system as defined in claim 17, wherein said radiation-sensitive surface of said first detector and said radiation-sensitive surface of said second detector are substantially coplanar.

Claim 25

A lens focusing system as defined in claim 17, wherein said first detector and said second detector are formed on a common substrate.

Claim 26

A lens focusing system as defined in claim 17, wherein said radiation-sensitive surface of said first detector is centered substantially on an axis defined by said reflected beam.

Claim 27

A lens focusing system as defined in claim 23, wherein said radiation-sensitive surface of said second detector is substantially concentric with said radiation-sensitive surface of said first detector.

Claim 28

A lens focusing system as defined in claim 17, wherein said radiation-sensitive surface of said second detector has an area substantially 25 times or more greater than the area of said radiation sensitive surface of said first detector.

Claim 29

A lens focusing system as defined in claim 17, wherein said radiation-sensitive surface of said first detector receives radiation in a prescribed ratio to the radiation received on said radiation-sensitive surface of said second detector, when said source beam is in optimum focus on the information bearing surface.

Claim 30

A lens focusing system as defined in claim 26, wherein said prescribed ratio is substantially 1:1.

Claim 31

A lens focusing system as defined in claim 26, wherein said prescribed ratio is other than 1:1, and further including: bias means, responsive to said source means, for altering said control means in response to variations in radiation power of said source beam, whereby said variations do not result in movement of said lens.

Claim 32

A lens focusing system as defined in claim 26, wherein said prescribed ratio is less than 1:1 and wherein said control means includes compensation means for compensating for non-linear changes in said second electrical signal relative to changes in said first electrical signal.

Claim 33

A lens focusing system as defined in claim 17, wherein said radiation-sensitive surface of said first detector is circular in shape.

Claim 34

A lens focusing system as defined in claim 30, wherein said radiation-sensitive surface of said second detector is annular in shape.

Claim 35

A lens focusing system as defined in claim 17, wherein said source means includes a laser.

Claim 36

A lens focusing system as defined in claim 17, wherein said reflected beam is directed from the information bearing surface through said lens along said second optical path, at least a portion of which is common to said first optical path.

Claim 37

A lens focusing system as defined in claim 17, and further including: auxiliary lens means, disposed in said second optical path substantially at said image plane when said source beam is in optimum focus on the information bearing surface, for refracting said reflected beam when said source beam is out of focus.

Claim 38

A lens focusing system as defined in claim 34, wherein said auxiliary lens means is centered substantially on an axis defined by said reflected beam.

Claim 39

A lens focusing system as defined in claim 34, wherein said auxiliary lens means comprises a concave lens.

Claim 40

A lens focusing system as defined in claim 34, wherein said auxiliary lens means comprises a concavo-concave lens.

Claim 41

A lens focusing system for use in a player for reading video information carried by a moving information carrier having a reflective surface, said system comprising: source means for producing a source beam of radiation to be focused on the reflective surface of the information carrier, at least a portion of said source beam being reflected from the reflective surface and modulated by the information carried by the information carrier; optical system means for directing said source beam along a prescribed optical path from said source means to the reflective surface and for directing the reflected beam of radiation therefrom, said optical system means including a lens, movable along said optical path, to focus said source beam on the reflective surface and to focus said reflected beam at an image plane removed from the reflective surface; transducer means, disposed in the path of said reflected beam non-coincidental with said image plane, for receiving said reflected beam, said transducer means including a first detector having a closed boundary defining a photosensitive surface of predetermined area substantially centered on an axis defined by said reflected beam, said first detector developing a first electrical signal indicative of the radiation from said reflected beam received thereon, and said transducer means further including a second detector having a photosensitive surface concentrically surrounding, but electrically isolated from and substantially coplanar with, said photosensitive surface of said first detector, said second detector developing a second electrical signal indicative of the radiation from said reflected beam received thereon; control means, responsive to said transducer means, for comparing said first signal with said second signal in a prescribed manner; and servo means, responsive to said control means, for moving said optical lens along said optical path to focus said source beam on the reflective surface of the information carrier.

Claim 42

A lens focusing system for use in a player for reading video information carried by a moving information carrier having a reflective surface, said system comprising: source means for producing a source beam of radiation to be focused on the reflective surface of the information carrier, at least a portion of said source beam being reflected from the reflective surface and modulated by the information carried by the information carrier; optical system means for directing said source beam along a prescribed optical path from said source means to the reflective surface and for directing the reflected beam of radiation therefrom, said optical system means including a lens, movable along said optical path, to focus said source beam on the reflective surface and to focus said reflected beam at an image plane removed from the reflective surface; transducer means, disposed in the path of said reflected beam non-coincidental with said image plane, for receiving said reflected beam, said transducer means including a first detector having a closed boundary defining a photosensitive surface of predetermined area substantially centered on an axis defined by said reflected beam, said first detector developing a first electrical signal indicative of the radiation from said reflected beam received thereon, and said transducer means further including a second detector having a photosensitive surface concentrically surrounding, but electrically isolated from and substantially coplanar with, said photosensitive surface of said first detector, said second detector developing a second electrical signal indicative of the radiation from said reflected beam received thereon; control means, responsive to said transducer means, for comparing said first signal with said second signal in a prescribed manner; and servo means, responsive to said control means, for moving said optical lens along said optical path to focus said source beam on the reflective surface of the information carrier.

Claim 43

A lens focusing system as defined in claim 38, and further including: means, responsive to said transducer means, for combining said first signal and said second signal to derive the information contained in said reflected beam.

Claim 44

A lens focusing system as defined in claim 39, wherein said combining means combines said first signal and said second signal additively.

Claim 45

A lens system as defined in claim 38, wherein said control means compares said first signal with said second signal differentially.

Claim 46

A lens focusing system as defined in claim 38, wherein said first detector and said second detector are formed on a common substrate.

Claim 47

A lens focusing system as defined in claim 38, wherein said photosensitive surface of said second detector has an area substantially 25 times or more greater than the area of said photo-sensitive surface of said first detector.

Claim 48

A lens focusing system as defined in claim 38, wherein said photosensitive surface of said first detector receives radiation in a prescribed ratio to the radiation received on said photosensitive surface of said second detector, when said source beam is in optimum focus on the information bearing surface.

Claim 49

A lens focusing system as defined in claim 44, wherein said prescribed ratio is substantially 1:1.

Claim 50

A lens focusing system as defined in claim 44, wherein said prescribed ratio is other than 1:1, and further including: bias means, responsive to said source means, for altering said control means in response to variations in radiation power of said source beam, whereby said variations do not result in movement of said optical lens.

Claim 51

A lens focusing system as defined in claim 38, wherein said prescribed ratio is less than unity and wherein said control means includes compensation means for compensating for non-linear changes in said second electrical signal relative to changes in said first electrical signal.

Claim 52

A lens focusing system as defined in claim 38, wherein said photosensitive surface of said first detector is circular in shape.

Claim 53

A lens focusing system as defined in claim 48, wherein said photosensitive surface of said second detector is annular in shape.

Claim 56

A method as defined in claim 50, wherein said first area and said second area are concentrically aligned on an axis defined by the path of the reflected beam.

Claim 57

A method as defined in claim 50, wherein said first area and said second area are substantially coplanar.

Claim 58

A method as defined in claim 50, wherein said first area is circular in shape.

Claim 59

A method as defined in claim 53, wherein said second area is annular in shape.

Claim 60

A method as defined in claim 54, wherein said first area and said second area are substantially coplanar.

Claim 61

A method as defined in claim 50, wherein the ratio of said second area to said first area is substantially 25:1 or more.