JPH01285027A - Optical pick-up device - Google Patents

Abstract

PURPOSE:To prevent the adhesions of a trash and a dust in an outside air onto a lens surface by providing a lens cover to be opened and closed in interlocking with a switch at a player side on the opening front surface of an objective. CONSTITUTION:A lens cover 18 to be opened and closed in interlocking with a switch 21 at the player side is provided in front of an objective 4. Namely, in the on-condition of a player power source SW21, the objective 4 is opened. At the time of taking out a disk 1 and making the player power source SW21 into an off-condition when a user stops the use of a player, the off-condition is detected by a lens cover driving circuit 20, a lens cover driving mechanism 19 is operated, a lens cover 18 is operated, and the opening surface of the objective 4 is covered with the lens cover 18. Thus, even when the disk 1 is removed at the time when a device is not used, the front surface of the objective 4 is covered with the lens cover 18, and the adhesions of the trash and dust in the outside air onto the lens surface can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an optical pickup device, and particularly to protection of an objective lens thereof.

[Prior Art] As a conventional optical pickup device, there is one shown in FIG. FIG. 3 is a block diagram showing the configuration of a conventional optical pickup device, in which (1) is an optical information recording medium (hereinafter referred to as a disk), (2) is a bit on the disk, (3) is a pickup holder, (4) is an objective lens, (5) is a coil, (6) is a half mirror, (7) is a diffraction grating, (8) is a semiconductor laser, (9) is a sensor lens, (10) is a photodetector, ( 11) is the optical pickup body, (12) is the audio circuit, (13) is the video circuit, (14)
) is the error signal detection circuit, (15) is the servo circuit, (1
6) is a coil drive circuit, and (17) is a semiconductor laser drive circuit.

The optical pickup device can be roughly divided into an optical pickup main body (11) as an optical system and a player side circuit, and the main optical path system of the optical pickup main body (11) is a semiconductor laser (
8), a half mirror (6), an objective lens (4), a sensor lens (9), and a photodetector (10).The drive system of the objective lens 4) includes an error signal detection circuit (14), a servo circuit 1 (15), a coil drive circuit (16), and a coil (5). Further, the output signal of the photodetector (10) is supplied to an error signal detection circuit (14), and at the same time, is supplied to an audio circuit (12) and a video circuit (13).

Next, the operation will be explained. In order to reproduce the information recorded on the disk (1) using the bit (2) on the disk (1), first the semiconductor laser (8) is caused to emit light by the semiconductor laser driving device (17).

The laser beam emitted by the semiconductor laser (8) passes through the diffraction grating (7) and passes through the half mirror (
6), enters and focuses on the objective lens (4), and is focused on the bit (2) as a light spot. The laser beam focused on this bit (2) is reflected with different reflection intensities depending on the information recorded there, and is reflected by the objective lens (4), the half mirror (6), and the sensor lens (9).
) and is focused on a photodetector (10). The light focused on this photodetector (10) is photoelectrically converted into an electric signal, one of which is supplied to the error signal detection circuit (14), and the other is supplied to the audio circuit (12) and the video circuit (13). )
are supplied to each.

The error signal detection circuit (14) monitors the focus shift of the objective lens (4), and if the laser beam is not focused on the - point of the bit (2) due to the focus shift, this is detected as an error signal. The servo circuit (15) and coil drive circuit (16) are operated to drive the objective lens (4) integrated with the coil (5), so that the light spot is always focused on the bit (2) on the disk (1). Objective lens (4
) is followed.

Further, the audio circuit (12) and the video circuit (13) reproduce the audio and video recorded on the disk (1) from the photoelectrically converted electrical signals.

[Problems to be Solved by the Invention] Since the conventional optical pickup device as described above is configured as described above, the disk (1) is placed above the objective lens (4) during use. However, if the disc 1) is removed when it is not in use, the objective lens (4) cannot be attached to the pickup holder (3).
The objective lens (4) is directly exposed to the outside air upward through the hole, and as time passes, dirt and dust from the outside air adheres to the surface of the objective lens (4), resulting in light passing through the objective lens (4). There was a problem in that the information was scattered and the information could not be reproduced normally.

The present invention has been made to solve this problem, and aims to provide an optical pickup device in which dirt and dust do not adhere to the surface of the objective lens (4) even if the device is left unused for a long time.

[Means for Solving the Problems] An optical pickup device according to the present invention is provided with a lens cover that opens and closes in conjunction with a switch on the player side in front of an objective lens.

[Function] In this invention, a lens cover that opens and closes in conjunction with a switch on the player side is provided in front of the objective lens, so even if the disc is removed when the device is not in use, the front surface of the objective lens This will be covered by the lens cover, making it possible to prevent dirt and dust in the outside air from adhering to the lens surface.

[Example code] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an optical pickup device according to the present invention. In the figure, the same symbols as in FIG. 3 indicate the same or corresponding parts, (18) is a lens cover, (19)
1 is a lens cover drive mechanism, (20) is a lens cover drive circuit, and (21) is a player power switch (SW).
W (21> is ON, the disc (1) is placed, and the lens cover (18) is open. In other words, the lens cover drive circuit <20) detects the ON state of the player power source 5W (21). and lens cover drive mechanism (19)
is operated to drive the lens cover (18) and open the objective lens (4). If the user stops using the player at this point, by removing the disc (1) and turning off the player power source 5W (21), the player power source 5W (21) can be turned off to drive the lens cover. It is detected by the circuit (20), and the lens cover drive circuit (20) is the lens cover drive machine! (19) is operated to drive the lens cover (18), and the aperture surface of the objective lens (4) is covered with the lens force bar (18).

FIG. 2 is a diagram showing an embodiment of the configuration of a lens cover and its driving mechanism according to the present invention. In the figure, the same reference numerals as in FIG. 1 indicate the same or corresponding parts, (22) is a transistor, (23) is an electromagnet, (24) is a piece of iron, (25),
(26) indicate pins, and (27) and (28) indicate springs. The example in Figure 2 shows when the device is not in use, the player power supply 5W (21) is in the OFF state, and the lens cover (18) is in the OFF state. The lens cover (18) is shown in a closed state, covering the front surface of the opening of the objective lens (4).

Next, the configuration shown in FIG. 2 will be explained. Similar to the conventional device, the aperture of the objective lens (4) can be seen through a round hole made in the pickup holder (3), but in this invention, the pickup holder (3) and the objective lens (4) are
) is provided with a lens cover (18), and this lens cover (18) has four holes as shown in the figure. Of these four holes, the hole marked AB has a bottle (26) press-fitted into the pickup holder (3).
are engaged, and a pin (25) press-fitted into the pickup holder (3) is engaged with the hole C. Furthermore, the remaining hole is filled with a spring (2) installed on the left wall of the pickup holder (3).
7), and a spring (28) is engaged with the hole E, and the lens cover (18) is attached so as to be rotatable about the bottle (25) as a fulcrum.

An iron piece (24) is attached to the back left of hole C of the lens cover (18), and on the other hand, to this iron piece (24),
An electromagnet (23) is arranged on the pickup holder (3) side, one terminal of this electromagnet (23) is connected to the base of the transistor (22), and the other terminal is connected to the standby power supply (STBY + 12V). has been done. Note that the standby power supply (STBY +12V) for driving the transistor (22) and the electromagnet (23) always supplies power regardless of the state of the player power supply 5W (21>).

Next, the operation will be explained. Player power supply 5W (21)
When is in the OFF state, the transistor (22) is turned OFF and the electromagnet (23) is not energized and does not operate. Therefore, the lens holder (18) is attached to the spring (27) and the spring (
28) is pulled to the left in the drawing,
The bottle (26) is in contact with the A side of the hole AB, and the lens cover (18) is in a closed state as shown in the figure.

When the player power supply 5W (21) is turned on,
The transistor (22) is turned on, the electromagnet (23) is energized, and a moment acts that tends to attract the iron piece (24) in the direction of the electromagnet (23). This moment causes the lens cover (18) to rotate counterclockwise about the pin (25), and considering the hole AB in the lens cover (18), the position of the bottle (26) moves from the A side to the B side. That is, when viewed from the round hole of the pickup holder (3), the lens cover (18) moves significantly to the left with respect to the objective lens (4). Therefore, by turning on the player power source 5W (21), the lens cover (18) is removed from the aperture of the objective lens (4), the lens cover (18) is opened, and the device becomes ready for use. .

In the above embodiment, the lens cover drive mechanism uses springs (27), (28), pins (25), (26), electromagnet 23), and iron piece (24), but the player power supply 5W ( The configuration is not limited to this, as long as the lens cover (18) is driven in conjunction with the state of 21).

Further, in the above embodiment, the lens cover (18) is driven in conjunction with the state of the player power source 5W (21), but if the disc (1) is separated from the pickup holder (3), for example in EJECT mode, The lens cover (18) may be operated to cover the aperture of the objective lens (4) by detecting the state in which the objective lens (4) is present.

[Effects of the Invention] As explained above, in this invention, a lens cover that opens and closes in conjunction with the switch on the player side is provided in front of the opening of the objective lens, so that the disc can be removed when the device is not in use. Even when the objective lens is covered by a lens cover, the front surface of the objective lens is covered by the lens cover, which prevents dirt and dust in the outside air from adhering to the lens surface, allowing high performance to be maintained for a long period of time.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an optical pickup device according to the present invention, FIG. 2 is a diagram showing an example of the configuration of a lens cover and its driving mechanism according to the present invention, and FIG. 3 is a block diagram showing the configuration of a conventional optical pickup device. FIG. 2 is a block diagram showing the configuration. (1) is a disk, (4) is an objective lens, (11) is an optical pickup main body, (18) is a lens cover, (19)
) is the lens cover drive mechanism, 20) is the lens cover drive circuit, (21) is the player power switch (SW), (
22) is a transistor, (23) is an electromagnet, (24) is a piece of iron, (25) and (26) are each a bottle, (27)
. (28) are each springs. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] a player power switch that turns on the power to the device; an optical pickup body that emits a light beam and focuses it on an objective lens when the player power switch is turned on;
In this optical pickup device, the optical pickup device includes a pickup holder that covers the entire optical pickup body and has an opening near the exit of the objective lens, and on which a disk is placed, the opening is opened and closed in conjunction with the player power switch. An optical pickup device characterized by being equipped with a lens cover.