JPH04105222A - Objective lens driving device - Google Patents

Abstract

PURPOSE:To suppress a recording medium flawed by separating a pressure sensitive element from the recording medium compulsorily when the pressure sensitive element comes in contact with the recording medium. CONSTITUTION:A lens holder 103 which holds an objective lens 102, a lens holder driving means 110 which drives the lens holder 103 in the focusing direction of the objective lens 102, the pressure sensitive element 107 provided at the lens holder 103 so as to be protruded to a maximum in the focusing direction, a pressurization detecting means 108 connected to the pressure sensitive element 107 in electrical circuit fashion, a separation signal generating means 109, and a focusing control means 110 are provided. When focusing control is performed erroneously, the pressure sensitive element 109 comes in contact with the recording medium 101 prior to contact with the lens holder 103 and another member held with the lens holder 103, and the lens holder 103 is separated from the recording medium 101 compulsorily by the pressurization detecting means 108 connected to the pressure sensitive element 109 in electrical circuit fashion, the separation signal generating means 109, and the focusing control means 110. In such a way, it is possible to suppress the recording medium flawed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention focuses on a recording medium such as an optical tinook, an optical card, or an optical tape, and records or records a signal using the reflected light or transmitted light. The present invention relates to an objective lens drive device used in an optical recording and reproducing device for reproducing data.

BACKGROUND OF THE INVENTION In recent years, in optical recording and reproducing devices, a beam emitted by a semiconductor laser or the like is condensed and irradiated onto a recording medium such as an optical diode, an optical card, or an optical tape using an objective lens, and the reflected or transmitted light is reflected or transmitted. Recording or reproducing signals is performed by In such optical recording and reproducing devices, focus control is performed by moving the objective lens, but in order to prevent damage to the recording medium in the event that the objective lens or lens holder hits the recording medium due to a control error, the objective lens Alternatively, it is common to provide a lens holder with a protruding member having a hardness lower than that of the recording medium base material.

An objective lens driving device used in a conventional optical recording/reproducing device will be described below.

Figure 3 is a schematic diagram showing a conventional objective lens drive device.
01 is a recording medium such as an optical disk, an optical card, or an optical tape; 302 is an objective lens for condensing and irradiating a luminous flux emitted by a semiconductor laser or the like onto the recording medium 301; 303
304 is a lens holder that holds the objective lens 302, and 304 is a lens holder that holds the objective lens 303 and the recording medium 30 of the objective lens 302.
305 is a plate spring that supports the lens holder 303 so as to be able to move in parallel in the focus direction; 306 is a base that holds the plate spring 305; 307 is an objective lens that protrudes in the focus direction. This is a scratch prevention member provided around 302.

In the objective lens driving device configured as described above, in order to condense and irradiate the recording medium 301 with a light beam, a focus control current is passed through the focus coil 304, and the focus is controlled by the action of a focus magnetic circuit (not shown). Do this. In this case, even if a control error occurs for some reason and the lens holder 303 approaches the recording medium 301, scratches provided around the objective lens 302 and having a hardness lower than the base material of the recording medium 301 Since the anti-stick member 307 stains the recording medium 301, it is possible to prevent the recording medium 301 from being scratched.

Problems to be Solved by the Invention However, in the conventional configuration as described above, if the scratch prevention member 307 comes into contact with the recording medium 301 for a long time, there is a problem that the recording medium 301 becomes unusable due to scratches.

In view of the above problems, it is an object of the present invention to provide an objective lens driving device that can significantly suppress scratches on the recording medium without causing the lens holder or the member held by the lens holder to hit the recording medium for a long period of time. This is the purpose.

Means for Solving the Problems In order to achieve the above object, the objective lens driving device of the present invention includes a lens holder that holds an objective lens, and a lens holder drive that drives the lens holder in the direction of focus of the objective lens with respect to a recording medium. a lens holder support means for supporting the lens holder so as to be movable in parallel in the focus direction; a pressure-sensitive element provided on the lens holder so as to protrude most in the focus direction; and a pressure-sensitive element that is pressurized by a recording medium. a pressurization detection means for detecting that the pressure has been applied; a separation signal generation means for generating a signal to separate the pressure sensitive element from the recording medium based on the detection signal from the pressurization detection means; and based on the output of the separation signal generation means, It has a configuration including a focus control means for controlling the lens holder driving means.

Function The objective lens driving device of the present invention has the above-mentioned configuration.
During focus control, the pressure-sensitive element comes into contact with the recording medium before the lens holder and other members held by the lens holder, and a pressure detection means connected to the pressure-sensitive element in an electrical circuit generates a separation signal. Since the lens holder is forcibly separated from the recording medium by the function of the focus control means, scratches on the recording medium can be significantly suppressed.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing the configuration of an objective lens driving device according to an embodiment of the present invention, and 101 to 106 are the same as the conventional configuration. Reference numeral 107 indicates a pressure-sensitive element provided on the lens holder 103 so as to protrude in the focus direction of the objective lens 102 than the lens holder 103 and other members held by the lens holder 103; and 108, the pressure-sensitive element 107 is connected to the recording medium 101 109 is a separation signal that generates a signal for forcibly separating the pressure sensitive element 107 from the recording medium 101 based on the detection signal from the pressure detection means 108. means of generation,
A focus control means 110 controls the focus coil 104 based on the output of the separation signal generator 8109.

The operation of the objective lens driving device configured as described above will be described below. When a focus control current is applied to the shift focus coil 104 by the focus control means 110, focus control can be performed by the action of a focus magnetic circuit (not shown). At this time, an error occurs in the focus control means 110 and the lens holder 103 is moved to the recording medium 1.
01, the pressure sensitive element 107 comes into contact with the recording medium 101 before the lens holder 103 and other members held by the lens holder 103, so the objective lens 102 directly touches the recording medium 101. It won't hurt. Next, when the pressure sensitive element 107 is pressed by contacting with the recording medium 101, the pressure detecting means 108 detects this and operates the separation signal generating means 109. The separation signal generating means 109 connects the recording medium 101 and the pressure sensitive element 107.
The focus control means 110 sends a signal to forcibly separate the
and focus control T[1
Reference numeral 10 applies a focus control current to the focus coil 104 to forcibly separate the pressure sensitive element 107 from the recording medium 101 .

As described above, according to this embodiment, the pressure-sensitive element 107 is forcibly moved away from the recording medium 101 due to contact between the pressure-sensitive element 107 and the recording medium 101, thereby preventing scratches on the recording medium 101. can be significantly suppressed.

In this embodiment, the pressure sensitive element 107 can take the configuration shown in FIG. By providing the scratch prevention section 107a and the pressure sensitive section 107b in close proximity to the recording medium 101, damage to the recording medium 101 that occurs when the pressure sensitive element 107 detects contact with the recording medium 101 can be prevented. Even slight scratches can be suppressed.

Effects of the Invention As described above, the present invention includes a lens holder for holding an objective lens, a lens holder driving means for driving the lens holder in the focus direction of the objective lens, and a lens holder provided in the lens holder so as to protrude most in the focus direction. By providing a pressure-sensitive element, a pressure detection means, a separation signal generation means, and a focus control means connected to the pressure-sensitive element in an electric circuit, when the pressure-sensitive element comes into contact with a recording medium, recording is forcibly performed. Since it operates so as to move away from the medium, it is possible to realize an excellent objective lens driving device that can significantly suppress damage to the recording medium when focus control is erroneous.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of an objective lens drive device according to an embodiment of the present invention, Fig. 2 is a block diagram of main parts of a pressure-sensitive element in the same embodiment, and Fig. 3 is a block diagram of a conventional objective lens drive device. It is. 101...recording medium, 102...objective lens, 103...lens holder, 1o4...
...Focus coil, 105...Plate spring,
106...Base, 107...Pressure sensing element, 108...Pressure detection means, 109...
- Separation signal generation means, 110...Focus control means. Name of agent: Patent attorney Akira Ho4Fsa and 2 others Figure 1//')/

Claims (2)

[Claims] (1) A lens holder that holds an objective lens, a lens holder driving means that drives the lens holder in a focus direction of the objective lens with respect to a recording medium, and a lens holder that supports the lens holder so as to be movable in parallel in the focus direction. a support means, a pressure sensitive element provided on the lens holder so as to protrude most in the focus direction, and a pressure detection means for detecting that the pressure sensitive element contacts the recording medium and is pressurized; A separation signal generation means for generating a signal for separating the pressure sensitive element from the recording medium based on a detection signal from the pressure detection means, and controlling the lens holder driving means based on an output of the separation signal generation means. an objective lens drive device comprising a focus control means for controlling the focus; (2) Claim 1, wherein the pressure-sensitive element provided in the lens holder comprises a scratch prevention section for preventing the recording medium from being scratched, and a pressure-sensitive section for sensing pressurization of the recording medium. The objective lens drive device described.