Optical devices for controlling a light beam

Claim 2

An optical device for controlling a light beam, the device comprising: a support member (18); a movable member (14) mounted on said support member (18) for rectilinear and angular movements relative to the said support member (18); an optical element (6) carried by said movable member (14) and acting on a light beam for effecting first and second kinds of control of said light beam in response to said rectilinear and angular movements, respectively; a first magnet (19) also carried by said movable member (14); and a second magnet (20) fixed relative to said support member (18) and shaped and magnetized to provide a magnetic field which reacts with said first magnet (19) yieldably to retain said movable member (14), and said optical element (6) carried thereby, against said rectilinear and angular movements from a stable balanced position relative to said support member (18).

Claim 3

An optical device according to claim 1 wherein said angular movements are about an axis (17) fixed relative to said support member (18) and said rectilinear movements are parallel to said axis (17), said first magnet is a bar magnet (19) which is magnetized in a longitudinal direction extending substantially radially with respect to said axis (17), and said second magnet (20) has a closed shape extending around said bar magnet (19) and is magnetized in a direction substantially parallel to said longitudinal direction of said bar magnet (19).

Claim 4

An optical device according to claim 2 further comprising a magnetic element (27) adjustably movable into said magnetic field of said second magnet (20) for varying the flux distribution in said field and thereby adjusting said stable balanced position of said movable member (14) and of said optical element (6) carried thereby.

Claim 5

An optical device according to claim 2 or claim 3 further comprising first and second electromagnetic means (25a, 25b, 26a, 26b) operative to cause said rectilinear and angular movements, respectively, of said movable member (14).

Claim 6

An optical device according to claim 4 wherein said optical element is an objective lens assembly (6) having an optical axis parallel to, and offset from said axis (17) of the angular movements and through which said light beam passes in the direction of said optical axis so that said rectilinear movements can vary the focus of said light beam at a surface and said angular movements can vary the position on said surface at which the focused light beam impinges.

Claim 7

An optical device according to claim 2 wherein said closed shape of said second magnet 20 is a circle.

Claim 8

An optical device according to claim 2 wherein said closed shape of said second magnet (20') is an oval.

Claim 9

An optical device according to claim 2 wherein said closed shape of said second magnet (20") is a rectangle.

Claim 10

An optical device according to claim 2 wherein said optical element (6) and said first magnet (19) are at opposite sides of said axis (17) about which said angular movements occur.

Claim 11

An optical device according to claim 2 wherein said optical element (6) and said first magnet (19) are both disposed on the same side of said axis (17) about which the angular movements occur.

Claim 12

An optical device according to claim 10 wherein said first magnet (19) is between said optical element (6) and said axis (17).

Claim 13

An optical device according to claim 10 wherein said optical element 6 is between said first magnet (19) and said axis (17).

Claim 14

An optical device according to claim 2 further comprising a bobbin (21) located within said closed shape of said second magnet (20) and having a central opening in which said bar magnet (19) extends with substantial clearance therebetween, said bobbin (21) having a first pair of projections (23a, 23b) extending generally parallel to said axis (17) and a second pair of projections (24a, 24b) extending generally at right angles to said axis (17), first coils (25a, 25b) on said first projections (23a, 23b) for receiving an electrical current for causing said rectilinear movements of said movable member (14), and second coils (26a, 26b) on said second projections (24a, 24b) for receiving an electric current for causing said angular movements.

Claim 15

In an apparatus for directing a light beam onto a record medium surface for optically reading information recorded in a track on said surface; an optical scanning assembly comprising: lens means (6) interposed in the path of said light beam and having an optical axis substantially coinciding with said path; a support member (18) having means (17) thereon defining a support axis; a movable member (14) mounted on said support axis for rectilinear movements along and for angular movements about said support axis; said lens means (6) being carried by said movable member (14) with said optical axis substantially parallel to, and offset from said support axis so that said rectilinear movements vary the focus of said light beam at said surface and said angular movements vary the position on said surface at which the focused light beam impinges; a first magnet (19) in the shape of a bar carried by said movable member (14) and magnetized in a longitudinal direction extending substantially radially with respect to said support axis; a second magnet (20) fixed relative to said support member (18) and having a closed shape extending around said first magnet (19), said second magnet (20) being magnetized in a direction substantially parallel to said longitudinal direction in which said first magnet (19) is magnetized to provide a magnetic field which reacts with the magnetic field of said first magnet (19) for yieldably resisting said rectilinear and angular movements of said movable member (14), and said lens means (6) carried thereby, from a stable balanced position relative to said support member (18); and first and second electromagnetic means (25a, 25b, 26a, 26b) selectively operative to cause said rectilinear and angular movements, respectively, of said movable member (14).

Claim 16

In an apparatus for directing a light beam onto a record medium surface for optically reading information recorded in a track on said surface; an optical scanning assembly comprising: lens means (6) interposed in the path of said light beam and having an optical axis substantially coinciding with said path; a support member (18) having means (17) thereon defining a support axis; a movable member (14) mounted on said support axis for rectilinear movements along and for angular movements about said support axis; said lens means (6) being carried by said movable member (14) with said optical axis substantially parallel to, and offset from said support axis so that said rectilinear movements vary the focus of said light beam at said surface and said angular movements vary the position on said surface at which the focused light beam impinges; a first magnet (19) in the shape of a bar carried by said movable member (14) and magnetized in a longitudinal direction extending substantially radially with respect to said support axis; a second magnet (20) fixed relative to said support member (18) and having a closed shape extending around said first magnet (19), said second magnet (20) being magnetized in a direction substantially parallel to said longitudinal direction in which said first magnet (19) is magnetized to provide a magnetic field which reacts with the magnetic field of said first magnet (19) for yieldably resisting said rectilinear and angular movements of said movable member (14), and said lens means (6) carried thereby, from a stable balanced position relative to said support member (18); and first and second electromagnetic means (25a, 25b, 26a, 26b) selectively operative to cause said rectilinear and angular movements, respectively, of said movable member (14).