JPH02168437A - Disc recording and playback device - Google Patents

Abstract

PURPOSE:To avoid damage to an objective lens and to improve the reliability by providing a brush eliminating dust adhered to an objective lens of a signal read section automatically and moving the brush and the signal read section relatively. CONSTITUTION:With a disk ejected, a brush 2 engaged with a holder 4 is moved toward a turn table 9 so as to be loaded in a moving area of a pickup 3. When the pickup 3 is moved toward the outermost circumference in advance in this case, the objective lens 1 passes while being in contact with the brush 2 and the dust on the lens is eliminated. As soon as the disk 13 is ejected, even if a lock van 10 is turned and lifted up, since the pickup 3 exists in a slidable range, the dust is completely eliminated by reciprocating the pickup 3 for several number of times under the control of a motor 6.

Description

DETAILED DESCRIPTION OF THE INVENTION [07J Field of Industrial Application] The present invention requires that it can be used for a long period of time even in a dusty environment and has high reliability against signal reading errors. C, D-
It relates to dust control structures for ROMs, optical discs, etc.

[Conventional technology]

Regarding dustproofing, conventional devices have been equipped with a shutter or the like in the disk insertion slot of the device, or a dustproof cover between the objective lens and the disk. Regarding dust removal mechanisms, there are those in which a disk with a brush attached is mounted inside the device and rotated, and those that are linked to the loading operation of the disk. For example, Japanese Patent Application Laid-open No. 62
-24449, the same town No. 63-52339, etc.

[Problem to be solved by the invention]

The above-mentioned conventional products do not have a mechanism to actively remove dust that accumulates on the pickup section before an abnormality occurs, and do not give much consideration to damage to the objective lens.
Moreover, the size of the device was also large. Particularly when used outdoors where there is a lot of dust, in the automated military, at textile-related industry sites, bookstores, exhibition halls with a lot of people, etc., dust accumulates on the dust cover and objective lens after several months, making it difficult to read. There were problems such as the inability to do so. If dust was removed every time a disk was inserted, there were problems such as accelerating damage to the lens.

The purpose of the present invention is to prevent dust from entering the signal reading section for reading disc information, and also to automatically remove dust that has accumulated on the pickup. To provide a structure capable of easily and manually removing dust at a low cost. Further, by storing the read signal state and controlling the mechanism, dust can be removed to prevent reading errors from occurring, and by reducing the number of dust removal operations, damage to the objective lens can be suppressed and reliability can be improved.

[Means to solve the problem]

In order to achieve the above-mentioned object, the present invention provides a dustproof wall around the signal reading section to change the inflow path of dust and prevent the dust from flowing into the pickup section.

Furthermore, assuming that dust still adheres to the signal reading section, a dust removal brush is provided, and the function is to remove dust by moving the signal reading section and the brush relative to each other.

Furthermore, a hole is provided in a portion of the above-mentioned structure of the pickup so that if the dust removal by the brush is insufficient, the dust can be removed using a cotton swab or the like while visually checking the dust. Additionally, this hole can be opened and closed to ensure safety against laser light and to prevent dust.

Furthermore, in order to activate the dust removal function, a control circuit section is provided which detects and stores the state of the read signal and automatically moves the signal reading section of the brush before a failure occurs.

[Effect]

Dust enters the device mainly through the disk insertion and discharge holes on the front of the device. The dustproof wall provided around the signal reading section prevents dust from adhering to the signal reading section and important mechanical parts within the device.

As dust accumulates on the top of the pickup, the level of the read signal decreases and the quality of the signal deteriorates. The control circuit unit compares the state of the signal with a certain reference value, and if the signal falls below the reference value, it is determined that dust has accumulated, and the dust removal mechanism can be driven.

When the dust removal brush is in the signal reading state, the dust removal brush
When the signal reader waits outside the movable range and the control circuit issues a signal indicating that the dust has been removed, each mechanism works so that the brush comes within the signal reader's movable range, causing relative movement between the signal reader and the brush. Accumulated dust is automatically removed. The control circuit section detects the signal quality again in the next signal reading state, so if it is insufficient, it returns to the dust removal state. A hole in the top of the device that can be opened and closed allows dust to be removed even more reliably.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. FIG. 1 is a diagram of a CD-ROM etc. during signal reading.

The signal on the disk 13 is read by the objective lens 1. Since the signal starts from the inner circumference of the disk 13, the pickup section 3 normally moves toward the disk motor 8 in the standby state. The anti-Jliil wall 7 is installed in front of the device from the disk motor 8, and blocks the flow of dust-containing wind coming in from the disk insertion/ejection port, thereby preventing dust from entering the pickup section. When the disc 13 is mounted on the turntable 9, the brush 2 engaged with the brush holder 4 is waiting at a position where it does not interfere with the rotation of the disc 13. During signal reading, the pickup section 3 moves to the inner and outer peripheries of the disk 13 while being guided by the guide bars 5 and 5' by the driving force of the motor 6. At this time, the position of the pickup section 3 is detected by a scale plate 14 having a groove and an optical sensor 16. Further, the lock pan 10 is rotatably engaged with the guide bar 5, and is disengaged from the protrusion 11 of the big part while the signal from the disk 13 is being read.

The kite 12 holds a caddy 23 containing a disc 13 from the left and right sides, and a guide plate 15 guides the guide 12 so that the disc 13 is attached to and removed from the turntable 9. Figure 1,
In FIG. 2, a portion of the guide 12 is shown cut away so that the operation can be seen.

Regarding the means for moving the brush 2, see Section 8. This is omitted for explanation in FIG. 9.

FIG. 2 is a diagram of the dust removal state. When ejecting the disc, the brush 2 engaged with the holder 4 moves toward the turntable 9 so as to be located within the movable area of the pickup 3.

At this time, when the pickup 3 is sent to the outermost circumferential side in advance, the objective lens 1 passes while contacting the brush 2, and at this time, dust on the lens is removed. Even if the lock pan 10 rotates upward at the same time as the disk 13 is ejected, the pickup section 3 remains within the slidable range, so the motor 6
By reciprocating the pickup section 3 several times under the control of
Dust removal becomes more complete. At this time, by vibrating the objective lens 1 up and down or in the inner and outer circumferences, it is expected that the dust removal effect will be further improved.

Furthermore, it is clear that the same effect can be obtained even if the pickup 3 is not moved but the plate 4 and brush 2 are moved back and forth.

In FIG. 8, the caddy 23 is inserted into the guide 12.

This is a view from below when starting. A shutter lever 30 is rotatably attached to the guide 12 via a support 32. A shutter opening/closing roller 31 is rotatably attached to the other end of the shutter lever 30 via a shaft 31a.

The shaft 31a is slidable along the guide hole 12b of the guide 12.

A brush holder 4 is installed in the middle part of the shutter lever 30.
is rotatably mounted.

A guide shaft 4a is caulked to the other end of the brush holder 4 so as to be slidable along a guide hole 12a of the guide 12.

Next, the operation will be explained with reference to FIGS. 3 to 9. The user is
The shutter 22 rotatably engaged with the panel 24 is pushed and the caddy 23 containing the disc 13 is inserted into the apparatus. At this time, in FIG. 8, the shutter opening/closing roller 31
comes into contact with the shutter 23a of the caddy. caddy 2
3, the shutter lever 30 rotates and the shutter 23a of the caddy opens. At the same time.

Brush holder 4 and brush 2 also move rearward.

FIG. 9 shows the caddy 23 inserted into the guide 12 to its deepest position. At this time, the shutter 23a of the caddy is fully opened and the disc 1 inside the caddy 23 is opened.
3 is raining. Also, the brush 2 has been moved to the rear of the caddy. Thereafter, when the guide 12 enters a certain amount with the caddy 23, it descends along the L-shaped groove 25 provided in the guide plate 15. At the same time, the lock pan 10 also rotates around the guide bar 5, allowing the pickup section 3 to slide. Then, as shown in FIG. 4, the disc 13 in the caddy 23 is mounted on the turntable 9.

Although not shown, there is a disk support in the caddy 23, and when the disk motor 8 rotates, the disk 13 rotates without slipping on the turntable 9. Such a guide mechanism using the caddy 23 and the aforementioned L-shaped groove 25 is well known. Thus, while reading signals from the disk 13, the pickup section 3 is moved to the inner and outer circumferences of the disk 13 by the guide bars 5 and 5' due to the force generated by the motor 6.

At the same time, the objective lens 1 is oscillated in the radial direction and vertical direction of the disk 13 so as to be able to follow the eccentricity and vibration of the disk 13. Even when the pickup section 3 is located at the outermost recording section of the disk 13, the brush 2 is placed at a necessary and sufficient position so as not to interfere with the pickup section 3 or the objective lens 1. The signal read by the pickup section 3 is processed by a circuit on one circuit board 18 and outputs a signal usually called an EFM signal. As shown in FIG. 7, the dust 27 deposited on the objective lens 1 reduces the intensity of the light beam 26 and
The intensity of the return light reflected on the recording surface No. 3 is also further weakened. When the EFM signal having the voltage level on the left side of the initial value as shown in FIG. 6 becomes less than 50% as shown on the right side, signal reading and servo circuit control become impossible. It is clear that the signal level decreases as the amount of accumulated dust 27 increases, and the increase in the amount of accumulated dust also changes over a period of several tens of days6. value α
The control circuit is designed to compare whether it is larger or smaller and to drive the dust removal function when it becomes smaller. When the signal level becomes smaller than the set value α.

The operation of ejecting the caddy 23 and the disk 13 is performed at the same time as sending the pickup section 3 to the outer periphery. At this time, the holder 4 and the brush 2 are positioned closer to the turntable 9 than the pickup section 3 and the objective lens 1 by a rope ink motor (not shown).

Thereafter, by reversing the IE flow applied to the motor 6, the pickup section 3 is caused to slide toward the inner and outer peripheries.

The tip of the brush 2 overlaps the objective lens 1 to a sufficient degree, and due to this relative movement, the dust 27 attached to the objective lens 1 is removed. As a result, the intensity of the light beam is restored and the level of the EFM signal is also restored. It is clear that the dust removal effect can be further improved by vibrating the objective lens 1 in its upper and inner and outer peripheries during this relative movement. When the pickup section 3 moves relative to the brush 2, the sliding stroke is controlled by reading the grooves of the scale plate 14 as pulses by the sensor 16. Further, the sliding speed is controlled by the current value applied to the motor 6. These control circuits are assembled on the circuit board 18. In addition, the lock pan 10 and the pickup section 3
The protrusion 11 provided on the guide bar 5 is engaged with the protrusion 11 provided in the guide bar 5 by the bias of the spring 28 just before the caddy is pulled out from the guide bar 5, and when the disc 13 is not present, an external force is applied and the pickup part slides arbitrarily to hold the guide bar 5. This prevents the club from receiving 1!1 impact. Furthermore, when the pickup 10 is in the outermost slidable range, even if a large external force is applied, the protrusion 11 of the pickup section 3 will move against the slope 33 of the lock pan 10.
Resisting the force of the spring 28, the strap engages with the groove 34 of the lock pan 10, and the pickup section 3 is fixed.

Further, it is clear that the same effect can be obtained even if the dustproof # 7 shown in FIG. 1 is formed as a part of the unit plate 17 as shown in FIG. 3. Furthermore, a dustproof wall 7 is provided at the bottom of the guide 12.
Defense f almost overlaps! ! Providing a wall 7' will produce a better effect. The anti-M wall 7' may be made of metal or sponge.

The embodiments have been described above, focusing on the dust removal mechanism. FIG. 10 provides a supplementary explanation of the relationship between the decrease in the output of the optical pickup and the elapsed time.

In the initial state, the optical pickup output signal is at an initial level without the influence of dust. As time passes, the output level decreases due to the influence of dust, and normally, when the output level decreases to about 50% of the initial level, reading errors of the recording medium occur and the device becomes inoperable.

Therefore, the detection level is set at an intermediate level, and the dust removal operation is performed before the level reaches the inoperable level. In the same figure,
Point A and point B correspond to this.

As a result of past experience, in the case of a recording and reproducing apparatus that does not implement the present invention, if it is installed in a place where there is a lot of dust, data reading failures occur after about three months.

On the other hand, FIG. 11 shows the above operation flow. A method of detecting the level of an optical pickup and issuing a warning to the user using a display device included in the recording/reproducing device;
It is also possible to use a method in which information at the level of an optical pickup is transmitted to the recording/reproducing device to forcibly perform a dust removal operation, thereby achieving more reliable dust removal.

FIG. 12 shows another embodiment of the invention.

The recording/reproducing device 127 is connected to an external device 128 (usually a computer or the like).

The recording medium 129 is irradiated with a laser beam from an optical pickup 131, and its output is connected to an external device 128 via a preamplifier 134, a signal processing circuit 135, an error correction circuit 136, and a control circuit 137. has been done.

On the other hand, the disk motor 130. optical pickup 131
．． The disk rope ink mechanism 132 and the optical pickup moving mechanism 133 are controlled by a servo control circuit 138.

The output level of the optical pickup 131 is the same as that of the preamplifier 1.
34, a control circuit 137 performs a comparison with a predetermined level, and if necessary, performs the above-mentioned dust removal operation via a servo control circuit 138. Usually, the control circuit 13
Reference numeral 7 uses a microcomputer to control each part of the recording and reproducing apparatus and to control data transmission and reception with the external device 128. As a result, in response to a request for the optical pickup output level from the external device [128], the information obtained by the method described above is sent to the external device 128 according to a predetermined command system, and as a result, the external device [128] A command from 1128 enables the above-mentioned dust removal operation.

〔Effect of the invention〕

According to the present invention, dust flowing in from outside the apparatus is prevented from adhering to the signal reading section of the disk.

In addition, the detection circuit processes the read signal to
Always check whether dust or the like has adhered to the signal reading section. Furthermore, if dust adheres, a control circuit is activated by a signal from the detection circuit, and the brush and objective lens move relative to each other to remove the dust adhering to the signal reading section.

Due to these, when used in environments with a lot of dust or cotton dust, or exhibition halls where many people bathe,
Devices that used to become unable to read signals after about six months and had to be disassembled and cleaned will no longer require maintenance for several years, making it significantly more economical. The reliability of ensuring a constant level of performance also increases.

In addition, even if the results of automatic decapitation are insufficient, you can clean it with a cotton swab or the like through the hole at the top of the device while checking visually, eliminating the need to remove the cover or board as required in the past. There is.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an embodiment of the present invention in which a disk is installed, FIG. 2 is a perspective view of the dust removal function in operation, FIG. 3 is a cross-sectional view of the disk being inserted, and FIG. 4 is a disk Figure 5 is a cross-sectional view of the rear part of the device when it is installed, Figure 5 is a cross-sectional view of the rear part of the device during decapitation, Figure 6 is a diagram comparing the level of the EF''M signal with the set value α, and Figure 7 is the view above the objective lens. Figure 8 shows the caddy with dust attached to it. Figure 9 shows the view from below when the caddy is inserted into the guide, and Figure 9 shows the view from below when the caddy is inserted into the guide. 10 is a diagram showing the relationship between the level reduction of the optical pickup output over time and the dust removal operation, FIG. 11 is a flowchart of the dust removal operation, and FIG. 12 is a block diagram of the recording/reproducing apparatus.1 ...Objective lens for reading signals, 2. Brush for dust removal layer, 3. Pick-up section, 4. Brush holder. 7. Dust-proof wall, 9. Turntable, 10..・
Lock pan, 13...Disk, 14...Scale pan, 15...Brush holder guide, 16...Scale pan groove sensor, 127...Recording/reproducing device ff
, 128... External packaging U, 129... Recording medium, 13
0...Disk motor, 131...Optical pickup, 132...Loading mechanism, 133...Optical pickup moving machine 49.134...Preamplifier, 1
35...Signal processing circuit. 136...Error correction circuit, 137...Control circuit,
138...Engraving of servo control circuit drawing No. 1 Fig. 2 No. 4 Fig. J

Claims (1)

[Scope of Claims] 1. A signal reading unit that reads out signals from a disk on which signals are optically recorded on a recording medium using an optical pickup;
A disk recording/reproducing device having a circuit section for processing read signals, a brush for automatically removing dust attached to an objective lens of the signal reading section, and a mechanism for relatively moving the brush and the signal reading section. 1. A disc recording/reproducing device comprising: a circuit section for controlling each mechanism; and a circuit section for controlling each mechanism. 2. The recording/reproducing device according to claim 1, wherein the upper structure of the device has a hole that can be partially opened and closed, thereby making it possible to remove dust. 3. The recording and reproducing apparatus according to claim 1, wherein the relative movement mechanism is activated when the read signal level of the disk falls below a certain reference level. 4. In claim 1, in the mechanism, a signal is applied to a device that drives the objective lens so that the objective lens is positioned at top dead center in order for the brush to contact the objective lens. A recording/reproducing device characterized by: 5. The recording/reproducing apparatus according to claim 1, wherein the brush contacts the surface of the objective lens at least once or more. 6. The recording/reproducing apparatus according to claim 1, wherein the mechanism is included in a mechanism for mounting the disc. 7. The recording/reproducing device according to claim 1, wherein the brush is removable. 8. The recording/reproducing apparatus according to claim 1, wherein the mechanism does not operate when the disk is rotating. 9. In claim 1, a control circuit operates to respond to a request from a device to which the recording/reproducing device is connected to determine the degree of decrease in the output signal of the optical pickup due to dust attached to the objective lens. A recording/reproducing device characterized by being provided with. 10. A control circuit according to claim 1, which operates to respond to a request from a device to which the recording/reproducing device is connected to determine the degree of decrease in the output signal of the optical pickup due to dust attached to the objective lens. and a control circuit capable of receiving information from the control circuit and forcibly driving the brush to remove dust on the objective lens. Device. 11. In claim 1, detecting that the output level of the optical pickup is reduced due to dust adhering to the objective lens, and displaying this information as a warning signal on a display device included in the recording device. A recording/playback device characterized by: 12. The recording and reproducing apparatus according to claim 1, further comprising a dustproof wall for preventing dust from flowing into the signal reading section. 13. The recording and reproducing apparatus according to claim 1, wherein the brush is attached to a lever that opens and closes a shutter of a caddy that accommodates the disc, or to a component synchronized with the lever. 14. The disk recording and reproducing apparatus according to claim 1, wherein the motor for moving the optical pickup and the movement guide shaft of the optical pickup are held by the same member. 15. The disk recording and reproducing apparatus according to claim 1, wherein a metal fitting for fixing the optical pickup is rotatably engaged with the guide shaft during transportation of the recording and reproducing apparatus. 16. In claim 1, the fixing fitting has a plurality of fixable ranges and non-fixable ranges within the sliding range of the optical pickup, and the latter range has a sloped shape. Disc recording and playback device.