Dynamic information storage or retrieval – Information location or remote operator actuated control – Selective addressing of storage medium
Reexamination Certificate
1999-04-15
2001-11-20
Hindi, Nabil (Department: 2753)
Dynamic information storage or retrieval
Information location or remote operator actuated control
Selective addressing of storage medium
C369S053290, C369S053390
Reexamination Certificate
active
06320824
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a method of controlling the position of an optical pickup head in an optical disc drive apparatus such as a CD (compact disc) drive apparatus, an MD (mini disc) drive apparatus, or a DVD (digital versatile disc) drive apparatus. This invention also relates to an apparatus for controlling the position of an optical pickup head in an optical disc drive apparatus. This invention further relates to an apparatus for detecting the position of an optical pickup head in an optical disc drive apparatus.
2. Description of the Related Art
A prior-art CD (compact disc) player includes an optical pickup head. When a CD is placed in the player, the optical pickup head starts to read out information from the CD. The prior-art CD player also includes a microcomputer and a traverse motor. The traverse motor serves to move the optical pickup head along a traverse direction between an inner most position and an outermost position with respect to the CD. The microcomputer is programmed to control the traverse motor.
The prior-art CD player further includes an innermost position switch connected to the microcomputer. When the optical pickup head reaches its innermost position, the body of the head encounters a control arm of the innermost position switch and changes the switch to its ON state. In this case, the microcomputer is informed that the innermost position switch changes to its ON state. The change of the innermost position switch to its ON state indicates that the optical pickup head reaches its innermost position. The microcomputer reverses the traverse motor in response to the change of the innermost position switch to its ON state. Accordingly, when the optical pickup head reaches its innermost position, the traverse motor is reversed so that the optical pickup head stops and then starts to move back toward its outermost position.
In the prior-art CD player, the connection between the innermost position switch and the microcomputer includes a pair of wiring lines, and a 2-pin connector. A simpler connection between the innermost position switch and the microcomputer has been desired.
SUMMARY OF THE INVENTION
It is a first object of this invention to provide a simple method of controlling the position of an optical pickup head.
It is a second object of this invention to provide a simple apparatus for controlling the position of an optical pickup head.
It is a third object of this invention to provide a simple apparatus for detecting the position of an optical pickup head.
A first aspect of this invention provides a method of controlling a position of an optical pickup head. The method comprises the steps of providing a first electrically conductive member on a control portion of a limit position switch for detecting whether or not the optical pickup head reaches a predetermined limit position; providing a body of the optical pickup head with a second electrically conductive member which moves into contact with the first electrically conductive member when the optical pickup head reaches the predetermined limit position, and which moves out of contact with the first electrically conductive member when the optical pickup head separates from the predetermined limit position; electrically connecting the second electrically conductive member to an electric portion subjected to a reference potential; detecting whether or not a potential of the first electrically conductive member is equal to the reference potential; and reversing the optical pickup head when it is detected that the potential of the first electrically conductive member is equal to the reference potential.
A second aspect of this invention provides a method of controlling a position of an optical pickup head. The method comprises the steps of providing a first electrically conductive member which is fixed; providing a body of the optical pickup head with a second electrically conductive member which moves into contact with the first electrically conductive member when the optical pickup head reaches a predetermined limit position, and which moves out of contact with the first electrically conductive member when the optical pickup head separates from the predetermined limit position; electrically connecting the second electrically conductive member to an electric portion subjected to a reference potential; detecting whether or not a potential of the first electrically conductive member is equal to the reference potential;
and reversing the optical pickup head when it is detected that the potential of the first electrically conductive member is equal to the reference potential.
A third aspect of this invention provides an apparatus for controlling a position of an optical pickup head. The apparatus comprises a first electrically conductive member; a second electrically conductive member provided on a body of the optical pickup head, the second electrically conductive member moving into contact with the first electrically conductive member when the optical pickup head reaches a predetermined limit position, the second electrically conductive member moving out of contact with the first electrically conductive member when the optical pickup head separates from the predetermined limit position; means for electrically connecting the second electrically conductive member to an electric portion subjected to a reference potential; means for detecting whether or not a potential of the first electrically conductive member is equal to the reference potential; and means for reversing the optical pickup head when it is detected that the potential of the first electrically conductive member is equal to the reference potential.
A fourth aspect of this invention is based on the third aspect thereof, and provides an apparatus further comprising a control circuit for the optical pickup head, the connecting means including means for electrically connecting the second electrically conductive member to a ground in the control circuit.
A fifth aspect of this invention is based on the third aspect thereof, and provides an apparatus further comprising a limit position switch for detecting whether or not the optical pickup head reaches the predetermined limit position, the limit position switch having first and second contacts, the first contact being electrically connected to the first electrically conductive member, the second contact being electrically connected to the detecting means.
A sixth aspect of this invention is based on the third aspect thereof, and provides an apparatus further comprising a suspension chassis for supporting the optical pickup head, an insulating member mounted on the suspension chassis, and the first electrically conductive member being provided on the insulating member.
A seventh aspect of this invention provides an apparatus for detecting a position of a movable optical pickup head. The apparatus comprises a first electrically conductive member; a second electrically conductive member provided on a body of the optical pickup head, the second electrically conductive member moving into contact with the first electrically conductive member when the optical pickup head reaches a predetermined limit position, the second electrically conductive member moving out of contact with the first electrically conductive member when the optical pickup head separates from the predetermined limit position; and means for detecting whether the second electrically conductive member moves into or out of contact with the first electrically conductive member to decide whether the optical pickup head moves to or from the predetermined limit position.
An eighth aspect of this invention provides an apparatus for detecting a position of a movable optical pickup head. The apparatus comprises a first electrically conductive member; a second electrically conductive member provided on a body of the optical pickup head, the second electrically conductive member moving into contact with the first electrically conductive member when the optical pickup head reaches a predetermi
Hindi Nabil
Matsushita Electric - Industrial Co., Ltd.
Woo Louis
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