JPS5824263Y2 - optical recording or reproducing device - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an apparatus for optically recording or reproducing information signals by projecting a light beam (for example, a laser beam) onto a recording medium such as a disk, and more specifically relates to an apparatus for optically recording or reproducing information signals by projecting a light beam (for example, a laser beam) onto a recording medium such as a disk. The present invention relates to an optical recording or reproducing device equipped with a dust protection mechanism.

2. Description of the Related Art In recent years, optical recording or reproducing devices have been developed that use light beams such as laser beams to record signals on recording media or read recorded signals.

An example of this type of optical reproducing device will be described with reference to FIGS. 1 to 3. The disc-shaped recording medium 1 has concavities or pits in the form of spiral tracks, as shown in FIG. 2, for example.
When an information signal such as a video signal or an audio signal is FM
recorded.

The width of pit 2 is approximately 1μm1 The depth of pit is approximately 1λ (
Here, λ is the wavelength of the laser beam), and in the case of a video disc, the length of the pit is different between the inner and outer sides, and is, for example, 1.5 to 6 μm.

As shown in FIG. 3, such a recording medium 1 includes a transparent resin layer 3 made of vinyl chloride or the like in which pits 2 are formed, an extremely thin reflective film 4 provided on this uneven surface, and a thin protective film 5 that protects the reflective film. It is composed of.

The recording medium 1 is a turntable 6 as shown in FIG.
For example, 1 is fixed by a clamper 7 on the
It is rotated at a speed of 800 r, p, m.

On the other hand, a light beam projection device 10 that projects a light beam 9 onto the recording medium 1 is driven by a drive device 11 to project a light beam 9 onto the disk-shaped recording medium 1.
is gradually moved in the radial direction of the recording medium 1.
is spirally scanned by the light beam 9.

Laser light emitted from, for example, a helium-neon laser light source 12 of a light beam projection device 10 disposed below the recording medium 1 is transmitted to a concave lens 13, a beam splitter 14, a Tλ polarizing plate 15, a rotating mirror 16, and a condenser. A light beam 9 is converged through the lens 17, and this light beam 9 is projected onto the recording medium 1.

The spot 9a of the light beam 9 on the recording medium is larger than the width of the pit 2, as illustrated in FIG. 2, and when scanning the pit 2, the reflected light inside the pit and the reflected light outside the pit cancel each other out, and the reflected output becomes small; when the beams are projected only outside the pit, there is no cancellation, so the reflected output becomes strong.

Therefore, a reflected light beam 9b having a strength corresponding to the presence or absence of the information signal pit 2 is obtained, and this reflected light beam 9b passes through the lens λ 17, the rotary mirror 16, the non-polarizing plate 15, and the beam splitter The signal reaches a detector 18, where it is converted into an electrical signal and sent to a demodulation circuit.

Tracking control is generally performed by changing the rotation angle of the rotating mirror 16, and light beam convergence control is generally performed by displacing the condensing lens 17 with a moving coil.

Incidentally, in the optical reproducing apparatus as described above, the light beam projection device 10 is disposed below the recording medium 1 in order to facilitate the attachment and detachment of the disk recording medium 1, and the light beam 9 is projected upward. be done.

Therefore, the portion from which the light beam 9 is projected from the condensing lens 17, that is, the light beam projection aperture, naturally faces upward, and dust tends to adhere thereto.

The adhesion of dust can be reduced to some extent by providing a partition plate between the recording medium 1 and the light beam projection device 10.

However, an opening must be provided in the path of the light beam, and there is a risk that dust may enter through this opening and adhere to the optical device.

Although the optical disc reproducing apparatus has been described above, similar problems exist in optical reproducing apparatuses other than disc reproducing apparatuses, and similar problems exist in apparatuses that optically record information signals.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an optical recording or reproducing device that can easily and easily reduce or prevent the ingress of dust.

To achieve the above object, the present invention provides a recording medium holding device that holds a recording medium in a substantially horizontal state, for example, which is removed from the turntable 6 and clamper 7 of the embodiment, and the recording medium held by the holding device. a light beam projection device that projects a light beam onto a lower surface of the recording medium for recording information signals on a medium or reproducing information signals from the recording medium; and the recording medium held by the holding device and the light beam projection. A dust prevention plate according to an embodiment, which is movably disposed between a light beam projection aperture of a device and is arranged to take a position that covers the light beam projection aperture and a position that does not cover the light beam projection aperture. a dust blocking member such as No. 27, and a position where the dust blocking member does not cover the light beam projection opening in response to an operation for setting a recording or playback state or a detection that the recording medium is attached to the holding device; The present invention relates to an optical recording or reproducing device characterized in that it is equipped with a dust prevention member moving mechanism such as the electromagnetic plunger 29 and the lever 33 of the embodiment for moving the dust prevention member.

According to the present invention, the dust prevention member is moved to a position where it does not cover the light beam projection opening in response to the recording or playback state setting operation or the recording medium attachment detection, so that the dust prevention member can be controlled. It is possible to provide a device that is automatically operated and has good operability.

Further, a special operating section for operating the dust blocking member moving mechanism is not required, and the configuration of the device is simplified.

Embodiments of the present invention will be described below with reference to the drawings.

First, the optical recording/reproducing apparatus according to the first embodiment of the present invention will be explained with reference to FIGS. 4 and 5.
A recording medium 1, a turntable 6, a light beam projection device 10, and other devices are housed in the housing 20, and the housing 20 is configured to perform recording or reproduction.

The basic parts of this apparatus for recording or reproducing are the same as the apparatus shown in FIG. 1, and the apparatuses shown in FIGS. (not shown), light beam projection device 10, drive device for the light beam projection device (not shown), disk clamper (not shown)
These are housed in the housing 20.

A support portion 21 fixed to the housing 20 rotatably supports a shaft 22, and a lid 23 is fixed to the shaft 22.

This lid body 23 is closed during recording and reproduction, and opened to a position where the recording medium can be inserted and removed when, for example, the recording medium 1 is replaced.

Reference numeral 24 denotes a partition plate that covers the light beam projection device 10 and other devices to protect them and improve their appearance.

The light beam projection device 10 disposed below the partition plate 24 moves in the radial direction of the disc recording medium 1, and the light beam 9 follows this and also moves in the radial direction of the disc recording medium 1. The plate 24 is provided with a long hole 25 extending in the radial direction of the disk to allow the light beam 9 to pass therethrough.

A guide rail 26 shown by a dotted line in FIG. 4 and only a part of which is shown in FIG. 5 is fixed to the lower surface of the partition plate 24 and guides a dust blocking plate 27 which also has a light beam shielding function.

A dust blocking plate 27 made of a material capable of blocking light transmission or attenuating light and having a function of blocking dust.
has a long hole 28 that substantially matches the long hole 25 of the partition plate 24,
The partition plate 24 slides between a position where the long hole 25 is blocked (a position where the light beam is blocked and dust is blocked) and a position where the long hole 25 is not blocked (a position where the light beam is allowed to pass).

In order to move the blocking plate 27 in both left and right directions in FIG.
An electromagnetic plunger 29 and a biasing coil spring 30 are provided.

One end of the coil spring 30 is connected to a pin 3 implanted in the blocking plate 27.
1, and the other end is locked to a pin 32 implanted in the partition plate 24, so that the blocking plate 27 is biased to the right in FIG.

Rotating lever 3 connecting blocking plate 27 and electromagnetic plunger 29
3 is loosely fitted into the pin 31, and the bent end is connected to the plunger 34 of the electromagnetic plunger 29.

35 is a pivot of the rotating lever 33, 36 is a buffer coil spring,
Reference numerals 37, 38, and 39 are operation buttons for setting playback, recording, and stop modes.

When reproducing an information signal with the apparatus configured as described above, the recorded recording medium 1 is placed on the turntable 6, fixed by a clamper (not shown), and the reproduction operation button 37 is pressed. operate.

As a result, a motor (not shown) and a drive device (not shown) are energized, the disk-shaped recording medium 1 rotates at a predetermined speed, and the scanning device, that is, the light beam projection device 10, moves in the disk radial direction. Start.

Further, by operating the operation button 37, an energizing circuit for the electromagnetic plunger 29 is formed, and the plunger 34 is attracted.

As a result, the rotating lever 33 rotates counterclockwise in FIG. 5 against the spring 30, presses the pin 31 to the left in FIG. 5, and moves the blocking plate 27 to the left in FIG. make it slide.

At this time, since the suction stroke, the arm length of the rotating lever, the stopper, etc. are set in advance so that the long hole 25 and the long hole 28 match, the long hole 25 and the long hole 28 are finally aligned with each other. The light beam 9 projected from the light beam projection device 10 is projected onto the lower surface of the recording medium 1 through the long holes 28 and 25.

In this embodiment, since the laser light source of the light beam projection device 10 is energized at the same time as the power switch is turned on, reproduction is started at the same time as the blocking plate 27 moves to the light beam passage permitting position.

Therefore, the reproducing operation starts up rapidly.

Even if the laser light source is energized in synchronization with the power switch being turned on as described above, the path of the light beam 9 is blocked by the blocking plate 27 until the playback operation button 37 is pressed, so the operator etc. The light beam never hits.

When the predetermined reproduction is completed and the stop operation button 39 is operated, the reproduction state is canceled, the rotation of the disk recording medium 10 and the feeding of the optical beam projection device 10 in one direction of the disk radius are stopped, and at the same time, the electromagnetic plunger 29 is stopped. It becomes a force.

As a result, the biasing spring 30 causes the blocking plate 27 to move to the fourth position.
Positions in Figures and Figure 5 (Light beam shielding and dust blocking positions)
The plunger 34 also returns to the position shown in FIG.

Therefore, even if the power switch is still kept on and the light beam 9 is emitted from the light beam projection device 10, it will be blocked by the blocking plate 27 and will not be emitted above this point.

Therefore, even if the eye comes directly above the light beam projection device 10 during the operation of opening the lid 23 and replacing the disk recording medium 1, the light beam 9 will not hit the eye.

Furthermore, even if dust or the like tries to enter through the elongated hole 25 during disc replacement, etc., the elongated hole 25 is blocked by the blocking plate 27. There is no possibility of dust adhering to the device and degrading its performance.

When the above-mentioned apparatus is used as a recording apparatus, an unrecorded recording medium 1 is mounted on a turntable fluro, and a modulated light beam modulated with an information signal is projected onto the recording medium 1 from the light beam projection apparatus 10.

Even in such a recording mode, the electromagnetic plunger 29 is energized in synchronization with the operation of the recording operation button 38, making it possible to project the light beam 9 onto the recording medium 1.

Then, when the recording mode is canceled, the long hole 25 is simultaneously blocked by the blocking plate 27.

As is clear from the above, according to this embodiment, the blocking plate 27 is located above the light beam projection aperture of the light beam projection device 10 and closes the long hole 25 of the partition plate except in the recording or reproducing state. This prevents dust from adhering to the optical device and damage to the optical device caused by something hitting the optical device due to the user's carelessness.

In addition, since the light beam projected from the light beam projection device 10 is restricted by the blocking plate 27 except in the recording or reproduction state,
It is possible to prevent the light beam from directly hitting the eyes.

Further, the blocking plate 27 is connected to the recording medium 1 and the light beam projection device-10.
Since it is placed between the recording medium and the recording medium, it is possible to obtain a blocking effect without interfering with the operation of attaching and detaching the recording medium.

Furthermore, in this embodiment, the blocking plate 27 is moved in conjunction with the operation button for setting recording or playback.
There is no need to independently operate the blocking plate 27, improving operability.

Next, a description will be given of FIG. 6, which shows a disc recording/reproducing apparatus according to a second embodiment of the present invention.

However, the illustrations and explanations of the same constituent parts as in the first embodiment will be omitted, and only the modified parts will be explained.

The difference from the first embodiment is that in the first embodiment, the electromagnetic plunger 29 is energized in conjunction with the operation of the playback or recording operation button 37 or 38, and the blocking plate 27 is moved to the light beam passage permitting position. On the other hand, in the second embodiment, the placement of the recording medium 1 on the turntable 6 is detected by an optical detection device consisting of a light source 41 and a light receiving element 42, and a detection output is obtained from this. When the light beam is released, the electromagnetic plunger 29 shown in FIG. 6 is energized, and the blocking plate 27 shown in FIG. 5 is moved to the light beam passage permitting position.

Other points are the same as the first embodiment.

Therefore, during a period when the disk recording medium 1 is not placed on the turntable 6, the blocking plate 27 shown in FIGS. Prevent entry into the device.

Furthermore, when the recording medium 1 is placed on the turntable 6 for recording or reproduction, the light emitted from the light source 41 is reflected by the recording medium 1, detected by the light receiving element 42, and obtained from the light receiving element. An energizing circuit for the electromagnetic plunger 29 is formed by the received light output, and the actuation of the electromagnetic plunger 29 moves the blocking plate 27 shown in FIG. 5 to the light beam passage permitting position.

As described above, in this device, before loading a recording medium into a predetermined position, the light beam projection device 10 is covered with the blocking plate 27 to prevent the light beam from hitting the eyes and dust from adhering to the optical device. Light beam projection becomes possible automatically when recording or reproducing.

Therefore, like the first embodiment, the device is extremely safe and easy to handle.

Note that after loading the recording medium 1 in the predetermined position, the recording medium 1
This prevents the light beam from hitting the eyes and prevents dust from entering.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-mentioned embodiments, and can be further modified.

For example, the loading of the recording medium 1 in the second embodiment may be detected by a method other than optical.

[Brief explanation of the drawing]

FIG. 1 is a front view illustrating an optical reproducing device, FIG. 2 is a plan view illustrating a recording medium, FIG. 3 is an enlarged cross-sectional view of the recording medium, and FIG. 4 is a first diagram of the present invention. FIG.
Fig. 6 is a partially enlarged longitudinal side view of the device shown in Fig. 6.
FIG. 2 is a partially longitudinal side view showing a part of the disc recording/reproducing apparatus according to the embodiment. In the symbols used in the same drawing, 1 is the recording medium;
2 is Pit, 6 is Turnchill, 9 is Light Beam, 10
is a light beam projection device, 20 is a housing, 23 is a lid, 24 is a partition plate, 25 is a long hole, 27 is a dust prevention plate, 28 is a long hole,
29 is an electromagnetic plunger, 30 is a coil spring, 33 is a rotating lever, and 37 is an operation button.

Claims (1)

[Claims for Utility Model Registration] A recording medium holding device that holds a recording medium in a substantially horizontal state; and a device for recording information signals on the recording medium held by the holding device or reproducing information signals from the recording medium. a light beam projection device that projects a light beam onto the lower surface of the recording medium; and a light beam projection device that is movably disposed between the recording medium held by the holding device and the light beam projection aperture of the light beam projection device; a dust prevention member disposed so as to take a position covering the light beam projection aperture and a position not covering the light beam projection aperture; and a dust blocking member moving mechanism for moving the dust blocking member to a position where it does not cover the light beam projection opening in response to detection of the presence of the light beam.