Apparatus for driving objective lens
First Claim
1. An apparatus for driving an objective lens in its optical axis direction for effecting a focussing control comprising:
- a cylindrical frame;
means for holding the objective lens;
a plurality of spiral leaf springs, each partially extending in a plane which is substantially perpendicular to the optical axis of the objective lens, each spiral leaf spring having a centrally located annular root portion fixed to the objective lens holding means and each sprial leaf spring having a plurality of arcuate arms having two ends occurring in a plane which is substantially perpendicular to the optical axis of the objective lens, a first end is fixed to said cylindrical frame and a second end is fixed to said annular root portion;
means for driving the objective lens in the optical axis direction in accordance with a focus control signal, thereby correcting any focussing error; and
a plurality of damping members partially extending in a plane which is substantially perpendicular to the optical axis of the objective lens, each of said damping members contacting a spiral leaf spring near said annular root portion of the spiral leaf spring.
1 Assignment
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Accused Products
Abstract
In an apparatus for driving an objective lens which projects a light spot onto an information track recorded spirally or concentrically on a disc-shaped record medium to read out information, a lens holder for holding the objective lens is supported by an intermediate cylindrical member by means of a pair of upright leaf springs movably in a tracking direction, the intermediate cylindrical member is then supported by an outer fixed cylindrical member via a pair of spiral leaf springs movably in a focussing direction parallel to an optical axis of the objective lens, dampers made of elastic material are secured to the upright leaf springs and the spiral leaf springs so as to suppress resonance caused by the leaf springs. Therefore, precise focussing and tracing controls can be carried out without being affected by the undesired resonance of the leaf springs.
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Citations
22 Claims
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1. An apparatus for driving an objective lens in its optical axis direction for effecting a focussing control comprising:
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a cylindrical frame; means for holding the objective lens; a plurality of spiral leaf springs, each partially extending in a plane which is substantially perpendicular to the optical axis of the objective lens, each spiral leaf spring having a centrally located annular root portion fixed to the objective lens holding means and each sprial leaf spring having a plurality of arcuate arms having two ends occurring in a plane which is substantially perpendicular to the optical axis of the objective lens, a first end is fixed to said cylindrical frame and a second end is fixed to said annular root portion; means for driving the objective lens in the optical axis direction in accordance with a focus control signal, thereby correcting any focussing error; and a plurality of damping members partially extending in a plane which is substantially perpendicular to the optical axis of the objective lens, each of said damping members contacting a spiral leaf spring near said annular root portion of the spiral leaf spring. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. An apparatus for driving an objective lens in its optical axis direction for effecting a focussing control comprising:
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a cylindrical frame; means for holding the objective lens; a pair of spiral leaf springs, each partially extending in a plane which is substantially perpendicular to the optical axis of the objective lens, each spiral leaf spring having a centrally located annular root portion fixed to the objective lens holding means and each spiral leaf spring having a pair of arcuate arms having two ends occurring in a plane which is substantially perpendicular to the optical axis of the objective lens, a first end is fixed to said cylindrical frame and a second end is fixed to said annular root portion; means for driving the objective lens in the optical axis direction in accordance with a focus control signal, thereby correcting any focussing error; and a pair of damping members partially extending in a plane which is substantially perpendicular to the optical axis of the objective lens, each of said damping members contacting a spiral leaf spring near said annular root portion of the spiral leaf spring.
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20. An apparatus for driving an objective lens in its optical axis direction and in a direction perpendicular to its optical axis direction for effecting a focussing control and a tracking control comprising:
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a cylindrical frame; means for holding the objective lens comprising an annular lens holder, an intermediate cylindrical body, a plurality of elongated leaf springs having a first end portion secured to said intermediate cylindrical body and a second end portion secured to the annular lens holder, the plurality of elongated leaf springs extending in a substantially parallel relationship with the optical axis of the objective lens, means for driving the objective lens in a direction perpendicular to said optical axis, thereby providing for a tracking control, and a plurality of first damping members, each damping member is provided adjacent said first end portion of each elongated leaf spring; a plurality of spiral leaf springs, each partially extending in a plane which is substantially perpendicular to the optical axis of the objective lens, each spiral leaf spring having a centrally located annular root portion fixed to said intermediate cylindrical body and each spiral leaf spring having a plurality of arcuate arms having two ends occurring in a plane which is substantially perpendicular to the optical axis of the objective lens, a first end is fixed to said cylindrical frame and a second end is fixed to said annular root portion; means for driving the objective lens in the optical axis direction in accordance with a focus control signal, thereby correcting any focussing error; means for driving the objective lens in a direction perpendicular to the optical axis direction in accordance with a tracking control signal, thereby correcting any tracking error; and a plurality of second damping members partially extending in a plane which is substantially perpendicular to the optical axis of the objective lens, each of said second damping members contacting a spiral leaf spring near said annular root portion of the spiral leaf spring. - View Dependent Claims (21, 22)
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Specification