JPS5810177Y2 - Information detection cartridge in recording disc playback device - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an information detection cartridge in a recording disc playback device, and in particular, when reproducing high-density information recording discs such as video discs, the present invention always maintains optimal contact between the recording disc and the contactor. An object of the present invention is to provide an information detection cartridge having a configuration that can be finely adjusted.

In general, when playing high-density information recording discs such as video discs, the shape of the information recording medium that must be handled is significantly smaller than that of conventional audio records, etc., so it is safe to consider the detection contact operation as a point for audio records. When considering the above recording disk reproducing mechanism,
It cannot be thought of as a point, but must be treated as being reproduced by a detecting object that is minute but has a finite size.

That is, the high-density information recording disk has, for example, a recording wavelength of 3 μm, a recording amplitude of 1 μm p-ps, a recording track width of 6, and a shortest wavelength of a conventional audio record of 30 μm;
1 @ 30 μm The recording density is much higher than that of 1 track width + μm.

Therefore, in the audio record reproducing apparatus shown in FIG. 1, even if there is a portion where the reproduction is unclear by about 2 to 3 .mu.m during reproduction, it is practically not a problem.

In the figure, 1 is an audio record, turntable 2
placed on top and rotated.

3 is the center shaft.

Vinyl records are usually 33 1/3, 45, and 78 rpm.
As a result, the arm I, which uses the arm shaft 8 as a support point and applies appropriate stylus pressure by the weight balance 9 and the pickup cartridge 5, also rotates around the shaft 8, and the stylus attached to the pickup cartridge 5 rotates. Draw a trajectory with the tip indicated by 4.

Here, 10 is a case, and 6 is a motor board.

Since any play in the arm 7 itself caused by the bending causes deterioration of the reproduced signal, special measures are usually taken to prevent play.

Therefore, as is well known, even if the horizontal tracking angle is adjusted accurately at one point on the inner and outer circumferences of the record, an error of several degrees or more will occur in other areas.

Further, the height of the arm 7 and the record 1 is strictly finely adjusted, and the angle of contact with the record 1 is determined by simply changing the height of the arm shaft 8.

Therefore, for example, when the pickup force on the record 1 and the pressing force of the cartridge 5 change due to the weight balance 9, the sinking weight of the cartridge stylus tip also changes, and the above-mentioned height relationship also changes effectively.

In the above playback device such as an audio record, the effects of the above error components are all within an allowable range.

Even though it is theoretically known that it is better to improve the above error components to a smaller value, the above improvements are not actively implemented at present because the effect is small compared to the efforts made for this purpose. .

On the other hand, when it comes to reproducing high-density information recording disks,
A mechanical error of about 2 to 3 μm can be fatal.

In other words, since the error component is larger than the recorded information, no information is reproduced at all.

Therefore, the recording disk is reproduced by a linear tracking reproduction apparatus as shown in FIG.

11 in the figure is a high-density information recording disk, turntable 1
2 and is rotated at high speed at 300 to 1800 rpm by a turntable drive motor 15 about a shaft 13 as a central axis.

A motor board 14 is supported together with the motor by a coupling 16.

The cabinet 11 is constructed of a shape and material that does not easily vibrate, and supports the turntable device via a damper material 18.

The cartridge 19 having the detection contact 20 is held and guided by the carriage 25, and the rotation of the motor 23 is transferred to the transmission element 2.
The recording disk 11 is driven by a drive mechanism 21 that is transmitted via a
is moved radially upward and to the left.

That is, since the information grooves of high-density information recording disks such as video discs are extremely small, it is not possible to apply enough force to the arm itself to which the cartridge 19 is attached to move the grooves, so the cartridge 19 is used instead of an arm. Then, the carriage 25 is forcibly moved by the motor 23, the transmitter 22, and the drive mechanism 21.

By the linear tracking operation described above, a constant tracking angle with no tracking error angle is maintained on the inner and outer peripheries of the recording disk 11.

Here, 24 is a holder mechanism of the IJ near tracking device, and the housing holder mechanism 25 is arranged in a half line on the recording disk 11, and the detection contactor 25 is arranged on the recording disk 11 over the inner and outer periphery reproduction.
The contact state of 0 is maintained uniformly.

In a recording disk reproducing device, a highly precise structure is used to minimize the vertical vibration of the turntable 12 in FIG. 2, and the jitter caused by wow and fluff is minimized. It has a structure that minimizes 1L11 unevenness as much as possible.

A reproducing apparatus with extremely small mechanical errors can perform high-density reproduction of a recording disk.

Figure 3 shows the state in which the detection contact is in contact with the recording disk.
Give an example.

In the figure, a contact element 26 is made of sapphire or diamond and is in contact with the recording information transducer 28 with a contact surface S.

The information track 28 is moved in the direction of the arrow α at a high speed of several claws per second or more, and the change in its unevenness reaches a maximum in the high frequency region 1.

Since the contactor 26 cannot vibrate up and down in the high frequency band 1, a predetermined pressing force (approximately 0.1 to 0.2 gr) is applied.
Utilizing the fact that the pressure changes at the sensing end β due to the change in the unevenness, the pressure change is detected as a longitudinal wave and transmitted to the pressure sensitive element 21 provided on the top surface of the contact 26. There is.

It should be noted that the impact due to the unevenness of the information track 28 can be sensed even on the contact surface S other than the point β, but since only the top of the convex portion slides, it is difficult to sense the pressure change.

On the other hand, at point β, the convex portion that had been pressed by the contact surface S is suddenly restored, so that a more uniform pressure change is obtained.

Here, the output voltage of the pressure sensitive element has a constant pressure change.

= In general, the detection contact of a high-density information recording disk reproducing device is
In order to stably pick up and reproduce the information recorded in an uneven shape on the information track 28 rotating at high speed, a certain pressing force is required, but in order to reduce the amount of weight per unit area, contact It has a side S.

This helps to prevent damage to the information l rank 28, and it has been confirmed that when a unit pressure exceeding lOt/C1ft is applied to the information track, the recorded information shape is rapidly damaged.

The detection contact therefore always has a contact surface S, but it is necessary that this contact surface S and the information track 28 are in correct contact as described below.

In FIG. 3, the recording angle of the information track 28 and the contact angle with the sensing end β of the contactor 26 are shown in the axis X plane.

This contact angle corresponds to the azimuth of the head gap in a magnetic recording/reproducing device.

For example, assuming that the recording wavelength of the information recorded on the information track 28 is 1 μm and the contact width of each contact 26 is 5 μm, the reproduction output becomes completely zero at an error angle of about 12°, and the detection and reproduction ability Lost.

At an angle slightly smaller than this error angle, or at an angle slightly larger than this error angle, the attenuation of the reproduced output is similarly large.

In an audio record playback device that has a tone arm that is fixedly supported at one point, an error of about the above error angle will occur.
This easily occurs as a tracking error angle between the inner and outer circumferences of the record.

Therefore, as explained in FIG. 2, the linear tracking reproducing apparatus which does not produce this tracking error angle is used for reproducing high-density information recording disks.

However, even if a linear tracking reproducing device is used, the sensing end β of the contactor 26 that is actually in contact with the disk must be equal to the recording angle.

Regarding this, since there are errors for each cartridge, fine adjustment is required.

The Y-axis is perpendicular to the plane of the information track 28.

If the angle between this Y axis and the sensing end β of the contactor 26 is not a right angle, one end of the sensing end β of the contactor 26 will make a dog contact with the recording track width, and the other end will rise.

This occurs because the pressing force is not applied uniformly to the contact surface S, but is applied as a biased force to one side, and the area of the upper contact surface S appears to decrease.

Therefore, the tendency of damage to the disc is extremely high, and the wear of the contact piece itself is also high.

If the above-mentioned tendency becomes even more serious, the contactor 26 may trace over the information track 28 formed in the grooves, resulting in a needle skipping phenomenon in which the contactor 26 jumps between grooves.

At this time, the guide groove may also be damaged, resulting in fatal damage to the recording disk.

Therefore, it has been confirmed that -C with respect to the Y-axis must suppress the error angle between the detection end β and the information track to within 2°.

Normally, a reproduced signal can be obtained even if the error angle is 2° or more.

However, the signal obtained in this case accelerates the wear of the contactor 26 and damages the grooves of the disc, so that the life of the disc is extremely shortened compared to the case under normal playback conditions.

That is, the error angle of the sum of X formed by the recording angle of the information track and the detection end β causes a decrease in the reproduction output and degrades the S/N, but does not damage the disk and the detection contact. On the other hand, the error angle with respect to the Y-axis does not cause a reduction in reproduction output, but there is a difference in that the disc and the detection contactor are mutually damaged.

The Z-axis determines whether the contact surface S contacts its contactor 26 uniformly in the longitudinal direction or whether it is pressed strongly at one end and weakly at the other end.

For example, in order to set the contact length of the contact surface S to 50Rn, the error angle in the Z-axis direction is approximately 0.
．． It must be within 21 degrees, and even if the contact length is 30 μm, it must be within about 0.4 degrees, requiring extremely strict accuracy.

If the error angle is greater than or equal to the above error angle, the pressing force will be applied to only one of both ends of the contact length.

In other words, when a strong pressing force is applied to the sensing end β,
The reproduction output level increases, and a phenomenon appears as if the sensitivity is being restricted.

However, in this case, the pressurizing force per unit area increases, resulting in damage to the disk and increased wear on the contact, which is disadvantageous.

On the other hand, a strong pressing force is applied to the other end of β, and the sensing end β
When the information track 28 is no longer in contact with the information track 28, no reproduction output can be obtained any longer.

The allowable value of the error angle of the Z-axis is actually about ±1°.

In other words, this error angle is of the order of magnitude that would easily occur if the cantilever was deflected due to changes in stylus pressure when conventional audio records were stacked or played back.

Therefore, it can be seen that the high-density information recording disk reproducing apparatus must be constructed so as to make the error angle in the Z-axis extremely small.

Furthermore, even if the requirements in the three axes of X, Y, and Z are met, a pressing force is applied perpendicularly to the information track surface on the contact itself, and the contact is separated from the disc except when playing a disc. The accuracy of the vertical mechanism becomes an issue.

That is, in this vertical mechanism, an error in the spatial position of the disk and the contactor causes phenomena such as excessive or insufficient pressing force on the cantilever's deflection.

Generally, the above-mentioned pressing force of about 0.1 to 0.2 gr is considered to be appropriate; if it is smaller than this, stable regeneration can be expected, and if it is smaller than this, it may cause damage to the disc and the contact.

The cantilever attached to the contact typically has a
．． When a pressing force of 3gr is applied, it is so soft that it sinks down to about -.

Therefore, when a pressing force of about 0.2 gr is secured, the cantilever is always depressed by about 0.65772 m.

Here, assuming that the cartridge itself sinks by about 0.3ml, the pressing force seen from the needle tip is about 0.3gr.
As a result, the above-mentioned appropriate pressing force is more intense than the above-mentioned appropriate pressing force, which may easily damage the disc, etc.

This relationship is the same throughout the inner and outer circumferences of the disk.

Therefore, in order to always apply the appropriate pressing force to the cartridge 19, the carriage 25 shown in FIG. 2 is parallel to the recording disk 11.

The cartridge 19, which is spaced apart from the disk 11 except when the disk 11 is being played back, is lowered to a height position where the above-mentioned appropriate pressing force can be applied and comes into contact with the disk 11 during playback.

If the cartridge 19 is replaced at this time, the pressing force will change because the spatial position at which the cartridge itself is attached and held relative to the disk 11 will be different.

Therefore, a high-quality information recording disk reproducing apparatus must be constructed so that the above-mentioned height is always constant.

On the other hand, in the disc playback device described above, after the cartridge 19 is attached to the cartridge 25, minute changes in its height can be corrected by the device.

However, in this case, only an expert who is familiar with the amount of deflection of the cantilever of the cartridge can make the above correction, and it is extremely difficult for a general user to make the above correction.

Furthermore, it is difficult to attach a weight scale to the reproducing device to detect minute differences in pressing force such as 0.1gr or 0.2gr.

Therefore, the correction of different height positions by replacing the cartridge in the reproducing device becomes difficult, and excessive pressing force may damage both the disc and the needle, or the signal may not be reproduced due to insufficient pressing force. The problem arises.

The present invention eliminates the above-mentioned drawbacks, and an embodiment thereof will be described below with reference to FIG. 4.

FIGS. 4A and 4B show a front view and a right side view, respectively, of an embodiment of an information detection cartridge in a recording disk reproducing apparatus according to the present invention.

In FIGS. 3A and 3B, 29 is a high-density information recording disk, and a detection contact 30 is brought into contact with this signal groove as shown in FIG.

Here, in FIGS. 4A and 4B, the disc 29 and the detection contact 30 are depicted as being slightly apart, but it goes without saying that they are actually used in contact with each other.

Further, 31 is a cantilever that holds the detection contact 30. This cantilever/bar 31 is a case 32 in which a head amplifier etc. for amplifying the playback output of the detection contact 30 is incorporated.
It is maintained by

A case holder 33 is provided on the upper part of this case 32.

3γ is a shaft, one end of which is divided into two parts to form a ball holder 34 so that the case holder 33 can be tightened thereon.

Further, the shaft 37 passes through the insertion base 38,
It is fixed by a center screw 36.

The above detection contact 30. cantilever 31, case 32,
Case holder 33, ball holder 34, set screw 35,
36, the shaft 3γ, and the insertion base 38 constitute the information detection cartridge of the present invention.

That is, the adjustment of the detection contact with respect to the X-axis shown in FIG. 3 can be performed by moving the case 32 on a plane parallel to the surface of the disk 290 in FIGS. This can be done by rotating the case 32 left and right in FIG. 4A.

Further, the detection contact 30 can be adjusted with respect to the Z axis by rotating the case 32 left and right as shown in FIG. 4B.

As a result, while observing the tip of the detection contact 30 with a microscope, fine adjustment is made so that the contact surface S can uniformly contact the information track, and then the set screw 35 is tightened.
Clamp with.

This causes the cartridge to be
The YZB axes can be held at accurate values.

Further, the spatial height between the disc 29 and the detection contact 30 can be adjusted by moving the shaft 31 up and down within the insertion space 38, and fixing it with a set screw 36 at a predetermined height.

Therefore, the detection contact 30 has all three XYZ axes and its vertical height position preset with respect to the insertion base 38, and is given accurate accuracy.

By inserting the information detection cartridge adjusted as described above into the holder 39 at an accurate position in advance and fixing it with the set screw 42, a desired contact relationship can be obtained.

Furthermore, the cartridge can be replaced by simply replacing the ridge of the above-described well-adjusted information detection car with the holder 39, and the desired contact relationship with the disc can always be obtained.

The button 40 is the lifting angle when the cartridge is separated from the disc 29 other than during playback, and this angle may be any suitable value.

However, when the detection contact 30 is brought into contact with the disk 29 for reproduction, the base 41 is positioned so that the base 38 itself remains at a predetermined spatial position.

Thereby, a predetermined pressing force can always be applied to the disk 29.

However, the cartridge of the present invention is not limited to the embodiment shown in FIG. 4, and of course there are various other modifications.

As mentioned above, the present invention is a contact method that traces the information track of a high-density information recording disk, such as a video disk, on which an extremely high-density information signal is recorded on a flat disk with a constant contact area. In an information detection cartridge that picks up and reproduces information signals using a contactor having a surface,
One fine adjustment means at least adjusts the contact angle of the sensing end of the contact angle to within a predetermined angle with respect to the recording angle of the information track, and also adjusts the contact angle of the sensing end of the contact between a perpendicular to the plane of the information track and the sensing end of the contactor. Since the angle formed by the contact element can be adjusted within a predetermined angle, the contact element can always be brought into contact with the information track of the disc in a uniform and optimal state, and when making fine adjustments, it is possible to use spacers or other There is no need to introduce and adjust components later, cartridge replacement is extremely easy and accurate, and in order to keep the pressing force of the contactor against the disc within a predetermined range as necessary, Since a means for adjusting the position height is provided, wear and tear on the playback contacts and discs is extremely small, and stable playback output can be obtained. The cartridge can be attached to the holder in the same state, which is simple, and there is no need to require strict precision from the components of the cartridge, and the structure is simple and can be constructed at low cost.

[Brief explanation of the drawing]

FIG. 1 is a plan view of an example of an audio record playback device.
FIG. 2 is a diagram showing the mechanism of an example of a high-density information recording disk reproducing device, FIG. 3 is a diagram showing the relationship between the information track of the high-density information recording disk and the detection contact of the cartridge, and FIG. B is a front view and a right side view, respectively, of an embodiment of an information cartridge for a recording disk reproducing apparatus according to the present invention. 1...Record, 2...Turntable, 5...Pickup cartridge, 11
...High-density information recording disk, 12...Turntable, 14...Motor board, 15.
...Motor, 19...Cartridge, 2
0...detection contact, 21...drive mechanism, 22...transmission element, 23...motor,
25...career sojourn, 26...contact,
21... Pressure sensitive element, 28... Recording information track, 29... High density information recording disk, 30
. . . Detection contact, 31 . . . Cantilever, 320. ... Case, 33 ... Case holding ball, 34 ... Ball holder, 31 ...
・Shaft, 38...Insertion base.

Claims (1)

[Scope of utility model registration request] An information signal is transmitted by a contactor having a contact surface that traces the information track of a high-density information recording disk, such as a video disk, on which an extremely high-density information signal is recorded on a flat disk with a constant contact area. In an information detection cartridge for picking up and reproducing information, one fine adjustment means at least adjusts the contact angle of the detection end of the contactor to within a predetermined angle with respect to the recording angle of the information track, and to make the contact angle of the detection end of the contactor within a predetermined angle and with respect to the perpendicular to the plane of the information track. An information detection cartridge for a recording disc playback device, wherein the angle between the contact and the detection end can be adjusted to within a predetermined angle.