JPS58211337A - Optical information reproducer - Google Patents

Abstract

PURPOSE:To prevent the output of laser light to the outside from a pickup which controls a shielding plate provided into an optical path through which the light beams are irradiated, by detecting the presence or absence of a disk loaded. CONSTITUTION:When a disk 8 is loaded, the light of a projector 14 is reflected by the disk 8 and made incident to a photodetector 15. The output of the detector 15 is supplied to a solenoid driving circuit 17 after the waveform shaping received through a shaping circuit 16. Thus a control signal showing the presence of a control signal is obtained. Then a plunger solenoid 13 conducts to pull down a shielding plate 11 unified with the solenoid 13 while expanding a spring 12. Thus no plate 11 exists in front of a light source 1, and the laser light passes through a collimator lens 3, etc. and reaches the disk 8 to perform reproduction of information. In this case, the laser light 2 is reflected by the disk 8 and is not delivered outside owing to the presence of the disk 8. If no disk 8 is loaded, the light 2 is cut off by the plate 11 and not delivered outside a pickup 100.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical information reproducing device that optically reproduces information recorded on tracks of a rotating disk using a laser beam, and particularly to a device that increases safety for users. .

Discs that reproduce information optically include minute reflective dots (hereinafter referred to as pits) whose shape is changed by 9 intervals to correspond to information such as video information. I have a video disc that I created using To reproduce information from this video disc, the video disc is rotated at a constant rotational speed, a beam is irradiated onto the track, and the reflected light modulated by changes in the pits recorded on the trunk is detected. This is done by converting the light into an electrical signal. This will be further explained with reference to the figure.

FIG. 1 shows a conventional optical information reproducing device. In this figure, a laser beam 2 emitted from a light source 12, for example a semiconductor laser, is shown.
is made into parallel light by a collimating lens 3, and this light is sent to a beam splitter 4, a quarter-wave plate 5 for changing the polarization direction, a movable mirror 6, and a condensing lens 7'l to a reflecting surface on a disk 8 with a diameter of 1 μm. Focuses the light on a small point. The bits of the Twiss 280 reflective surface are formed with a trunk pitch of about 21 tm and a width of 1 μm or less in accordance with the information. The reflected light from this point 1-' is reflected by the condensing lens 71.
iiJIII1m6. 1. After passing through the /4 wavelength plate 5, the beam is separated by a beam snoritter 4 and enters a photodetector 9. The photodetector 9 converts the reflected light into an electrical signal and reproduces the information recorded on the disk 8.

-4. Here, the 1/4 wavelength plate 5 works in cooperation with the beam slitter 4 to efficiently separate incident light and reflected light. For example, the disk 8 is 18 by the electric motor 101C.
The pink-up 100 rotates at 00 RPM and is moved in the radial direction as the disk 8 rotates in order to continuously reproduce the information arranged in a concentric circle. Then, such a device is housed in one case 200 together with the output signal of the photodetector 9, an electric circuit for performing electrical demodulation processing, etc., to form a final configuration.

Here, the case 200 serves as a stylish casing for the optical information reproducing device, and at the same time serves as a protective cover to prevent the Rayleigh 22 from coming into contact with the user's eyes.

There is no problem as long as the device is completely sealed, but if, for example, the disk 8 is to be replaced, part of the case 200 is a lid that can be opened and closed, and the lid can be opened to remove the disk 8. It is common to exchange them.

Even when the lid of the case 200 is opened and functions as a protective cover, the laser beam 2 turns pink.

100 is dangerous because it may cause damage to the user's eyes or other body unless it is kept in a state where no light is emitted.

This invention was made to avoid the above-mentioned dangers.
This invention provides a method for controlling means for shielding laser light by detecting the presence or absence of a disc.

Figure 2 is a configuration diagram showing an embodiment of an optical information reproducing apparatus according to the present invention.

In this figure, a shielding plate 11 that is movable in a direction orthogonal to 1/-the 2 is provided between the light source 1 and the three collimating lenses. One end VC of the shielding plate 11
A spring 12 is suspended 9 and biased in one direction. At the end of the shielding plate 11 opposite to the spring 12, there is provided a plunger solenoid 13 that moves the shielding plate 11 in the /,,) direction orthogonal to the laser beam 2.
, the aforementioned shielding plate 11. A shutter mechanism is formed in cooperation with the spring 12.Also, as a means for detecting the presence or absence of the disk 8, for example, if a light emitter 14 and a light receiver 15 are installed, the light from the emitter 14 will be emitted if the disc 8 is present. It can be reflected by the disk 8 and detected by the light receiver 15.
The output signal of the light receiver 15 that detects the presence or absence of the disc 8 is
a control signal for driving the plunger solenoid 13, which is the power source of the shutter mechanism;
? 9, which is input to the solenoid drive circuit 17.

Next, the operation will be explained - f7. . Now disk 8 is the second
When installed as shown in the figure, light emitted from the light projector 14 is reflected by the disk 8 and enters the light receiver 15. Photoreceiver 15
Output signal ii\The waveform is shaped by the shaping circuit 16 and distorted/
This signal is input to the disk drive circuit 1.I as a control signal indicating that the disk is present. When the control signal indicating that the disk is present is input, the solenoid drive circuit 17 is set to energize the plunger solenoid 13' (2).Since the plunger solenoid 13 attracts the plunger by electromagnetic force, When energized, the 7° langeer is attracted, and the 11 shielding plates and spring 12 that are integrated with it are stretched and pulled down.In this way, the shielding plate 11 becomes in front of the light source 1 from '/j:,/). Laser light 2 passes through collimating lens 3
1. The light reaches the disk 8 through the channel C, is reflected and enters the photodetector 9, and the information is reproduced.

At this time, the laser beam 2 is reflected by the disk 8, so the disk 8 acts as a shield and the laser beam 2 does not come out.

Conversely, if there is no disk 8, the light from the emitter 14 does not enter the light receiver 15, so there is no output signal from the light receiver 15, so no control signal is input to the solenoid drive circuit 17. If there is no control signal, use the No Langer Refit 1.
Since the plunger solenoid 13 is not energized, the plunger solenoid 13 has no suction force (1,c), and the shielding plate 11 is pulled up by the restoring force of the spring 12. Plate 11 (Ronode, 1/-the light 2
It is safe because it is blocked and does not come out of the pickup 100.

In the above embodiment, the 11 shielding plates are placed between the light source 1 and the frimate lens 30. However, the shielding plates are not limited to this position, and may be placed anywhere on the incident optical path up to the light source 8.+1 Of course.

Mom, the shield plate 11 is the planner solenoid 13 A1! When the shield is removed and the current is turned off, the pressure applied by the spring 12 to shield the laser beam 2 is increased.
Reverse this to create a shielding configuration when energized.
There is no problem.

As explained in detail above, according to the optical information reproducing device according to the present invention, when the disc is replaced, etc., the case lid is opened and the case acts as a protective cover. In such cases, the light beam is always blocked by a shielding plate, which prevents the laser beam from coming out from the pickup, which has the effect of guaranteeing safety.

[Brief explanation of the drawing]

Figure 1 is a configuration diagram showing a conventional optical information reproducing device;
The figure shows an embodiment of the optical information reproducing device according to the present invention. In the figure, 1 is a light source, 2 is a laser beam, 3 is a collimating lens, 4 is a beam splitter, and 5 is a 1/4 Wave plate, 6 is a movable mirror, 1 is a condenser lens, 8 is a disk, 9 is a photodetector, 1
0i1 is an electric motor, 11 is a shielding plate, 12 is a spring, 13 is a Grangers remade, 14i1 is a projector, 15 is a light receiver, 16 is a shaping circuit, and 17 is a solenoid drive circuit. Note that the same reference numerals in the figures indicate the same or corresponding parts. Agent Shin Kuzuno (1 other person)

Claims (1)

[Claims] (1) An optical system that irradiates a light beam onto the information track of a disk on which information is recorded concentrically or spirally and receives the reflected light.The light beam from the pickup is rotated and In an optical information reproducing apparatus that reproduces information by irradiating light onto the information track, an optical information reproducing apparatus is provided with means for detecting whether or not the disc is mounted, and a means for detecting whether or not the disc is mounted, and a means for detecting whether or not the disc is mounted; An optical information reproducing apparatus characterized in that a filter shielding plate is provided, and a driving means is provided for driving the shielding plate into and out of the shielding plate by the output of the means for detecting whether or not the disc is attached.+21!Hei The optical information reproducing apparatus according to claim 1, wherein the driving means for driving the nine plates in and out is formed of an electromagnetic shutter.