JPS6066334A - Servo device of optical pickup - Google Patents

Abstract

PURPOSE:To execute stable servo operation in spite of flaws and vibration by extracting a relative signal between a movable part and a fixing part of an optical pickup for a servo, mixing the relative signal with a servo error signal and executing the servo operation by the gain of a servo signal in high frequency. CONSTITUTION:Error signals from feedback amplifiers B1, B2 are mixed with a reference set voltage VE and the mixed signal is inputted to a driving coil 6 for the optical pickup through an amplifier A1. On the other hand, the movement of the fixing part of the optical pickup is detected by a detecting coil 9 and a tracking error signal is obtained. These signals are fed back to their inputs through the feedback amplifiers B1, B2 respectively. High frequency loop gain of the feedback amplifier B2 is reduced and an equalizer corresponding to acceleration in a low frequency and an equalizer corresponding to speed in a high frequency are inserted into the loop of the feedback amplifier B1 to increase the total gain in the high frequency. Consequently, the servo operation is executed by the loop gain mainly based upon the servo error signal in the high frequency, so that stable servo operation is executed in spite of flaws and vibration.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pick-up device that generates an original rod disk 91. In addition, the optical pickup servo device, which can detect scratches, dirt, scratches, and disturbances on the video disc, as well as dynamic dynamic pressure.

Conventionally, in the J-point digital audio disc (DAD), video disc (VD), etc., it is necessary to perform a track servo or a focus servo using a very small track all-optical head. In general, the cystic motion forces included in the disk include eccentricity, warpage, unevenness, etc. In the 2jK1 diagram, the horizontal axis shows the frequency (vs.) When the gain is taken to ll, the curve N
As shown in , the J and N wave numbers become better, and the fluctuation factors are reduced. To do this correctly, first
It suffices if there is an external servo log gain as shown in Figure A. However, Discze 1st year student, J1. : When considering all the IF settings, in order to prevent servo deviation such as when vibrations are added from the outside /ζ1::4', use a large gain such as 1st + = n with as large a voltage loop gain as possible. Delicious.

However, at this point, noise due to dust and the like is added to the error 1fl:i from the optical pickup due to the fact that there is i.-5- and dust on the disk.

The noise fraction due to F3 dust, scratches, etc. is relatively higher than components such as eccentricity, as shown in S.
It extends to q bζ. For this reason, the loop gain is
The lower the setting is, the more the turbo yarn responds to these noise S components, causing serious errors such as track misalignment and track jumps. Also, in order to stabilize the servo system, it is necessary to increase the loop gain as shown in Figure 1 A- or B-B' to further raise the high range as shown in A-A or B-B. It has the disadvantage that the servo system responds even more to the noise component S. In this way, the loop gain is large in response to external vibrations, and the loop gain is small in response to disk noise, which are contradictory. There were some popular books which had many fruits and it was difficult to satisfy them at the same time.

OBJECTS OF THE INVENTION The present invention has been made to solve the above-mentioned drawbacks, and in these servo systems, between the moving part of the 0 pickup and the fixed part of the 1d. The overall purpose of this invention is to provide an optical pickup servo device that is effectively mixed with the servo engine No. 13 that has been removed.

According to Yumei Moto, the purpose of the above is to extract the servo error signal from the disk surface, and to improve the relative signal range between the moving and fixed parts of the pickup in a disk player that performs all servo operations on the original pickup.9 The optical pickup servo device YJL is characterized in that the optical pickup servo device YJL is characterized in that it is mixed with the servo error signal and performs servo mainly with the loop gain of the servo error signal in the high range.

Embodiments of the Invention In the following, descriptions will be made with reference to Figures 2 to 2135.
Write r.

FIG. 2(a) is a diagram showing the main parts of the pickup, in which the optical head 1 is attached to the tip 1 of the swing arm 2, rotates fully around the shaft 3, and communicates with the objective lens 4-.
419. The laser was sent to Kanayama, and the i'i7 report on D was verified.419. Ru.

Of course, nons; .

Actuator ↑41i t, Il, 1 in Figure 2 (b)
An example of the location drawing is shown, but the swing arm 2 has J'! ,
Iil coil 6 is fixed, a magnet 7 is arranged below this, and a yoke 8 is inserted into the coil 6 to form the yoke I'.
J,ii! +i, and a gap is provided between the swing arm and the coil 6 to prevent collision even when the swing arm rotates. Here, by applying one streetcar to this coil 6, the magnetic flux flowing from the magnet 7 to the yoke 8 in all the coils 6 is cut and the swing arm 2 is fully driven, thereby operating as a so-called linear motor. This coil 6 performs track servo, and the track signal on the disk D is reproduced by the original pickup 1, and a track error signal 11 is generated.
As in the past, it can be removed by three beams or by a known means such as a push-pull method. -Blade fixing magnet 7
Below the drive), there is a detection coil 9 and a yoke 10 on the arm 2, as in the case of Figure 5, and this detection coil 9 causes the ! A voltage proportional to the speed of 1 () is drawn out.

Next, as the third factor, a diagram of the original pickup servo lock of the present invention will be shown and explained below. The error with respect to the reference setting voltage V□ is mixed in the '1 color combiner 12, passed through the amplifier Ai,
A person falls into the helper coil 6. The original pickup is activated by this coil. - In this embodiment, a signal corresponding to Jjli J& of the optical pickup is obtained, in which Lpl is output from the entire motion detection coil 9 relative to the fixed part of the tip pickup. At the same time, the track error signal 11 is outputted from the signal reproduced from the original pickup, as in the conventional case. , B
, through the person Kahekaku, return 1.) Isano L stone.

The characteristics of a normal big amplifier are b'J1+5h-xXB-
As shown in B', the higher the frequency, the higher the frequency, the lower the response amplitude is. On the other hand, the component N, which is necessary for track servo such as eccentricity of the disk, also drops at 12 dB/oat as shown in the figure, and these are just the characteristics that make the acceleration constant. Generally speaking, as explained earlier, the h of the servo system is constant, so in order to have a phase margin where the gain is zero, the 1144 pole is raised as shown in Figure 4 (a). I will return it.For this reason; l!
1. Usually, the gain is set as shown in Figure 1 A-A or as shown in B-H.

Here, in the present invention, the frequency battle characteristics of the loop system using the conventional feedback amplifier B2 are shown in FIG. 4 (B), or rather (C).
Lower the high frequency loop gain as shown below.

On the other hand, No. 13 from the detection coil 9 corresponds to the speed, and track error 1+: E, 1 for the position where No. 4 is No. 11.
Rise by 6 dB/oCt to >9 returnffl for speech
Amp B's Gay 7 f 7. f, 4 in, 1)
Define 1 as Qζ and si+) 1+t The entire roof including the outputs of amplifier 131 and B2.

The gain is the same as that of the follower, like A-A or &:, t B-B. Here, the overall gain is 3'L BB swing', which is strong for B-13 songs. I: Even if it is set to ``disk type'' (for ``13-13', BB''
Since the gain in the high range is high, the servo can be performed stably without changing the stability of the loop. Therefore, the overall loop gain can be large, and it is strong against external erosive forces, and the disk It is difficult to respond to noise caused by flat blowers, etc.
311 Flash A-A', lower return J1 amplifier B rule.
A more modern version can be obtained if the loop is fed back like 1-B-B, which is a 4-combination loop gain with a full equalizer that corresponds to acceleration in the low range and speed in the high range.

In the above embodiment, a swing arm type pickup system is shown, but an embodiment of the lens system k i''!+kas i is shown in FIG. 5(a).

Lens 4 is supported by two analytical springs 1, 3 and 14.
Focus on the honey! ji<fixed to the moving coil 16.

The lens system is formed into upper and lower parts 1 by a coil 16. Although not shown, a magnetic circuit covers the coil 16. There is a magnet 20 in the lens part, and a driving coil is provided in the fixed part to deworm the whole lens system in the direction of the track.
Shitsuru. Leaf spring 14", protrusion 17 noba y>9, all scissors, light emitting element 18 and light reception! The L4 element 19 corresponds to the moving part of the lens system in the track direction (arrow), and the light receiving element 19 detects the loop of the return amplifier B2 of the 31st PL. Totsutsuru.

Of course, if you work on displacement output for a while, you can achieve speed output. Also, if you insert a mirror in the middle of the optical path and change the angle of the mirror, the angle of the mirror can be changed in the same way.
I can do it. Also, even if the focus servo is 7b-, it does not indicate IB+, but it is 0Tf4i'' to detect all the upper and lower parts of the lens system using the speed detection coil or optical detection).

As described above, according to the invention, at low frequencies, servo is mainly performed using the error signal obtained from the disk, and l! 3
In the area, the movement amount of the Q moving part of the pickup is 4:"'
! By outputting -ν/-, it is possible to obtain a complete servo system that is stable against scratches and vibrations.

[Brief explanation of the drawing]

Fig. 1 is a servo gain diagram showing the relationship between frequency and gain, Fig. 2 (a) is the main slope of the pickup used in the invention (J, ! Fig. 21%l (b) is 21st 2 The 911 disconnection ++iT diagram of the Akchefta in Figure (A), Figure 3 is the system diagram of the pickup servo device according to the present invention, and Figure 311 is the system diagram of the pickup servo device according to the present invention. , a servo gain diagram for clarity, and FIGS. 5(a) and 5(b) are a perspective view and a flat curved view of a detection means showing another embodiment of the proposed invention.
Swing arm 3...Shaft 4...Objective lens 6...JJI 1liJt coil 7...Magnet 8Φ...Yoke 13.14...Plate spring 16...e
Focus, small moving coil 17...Protrusion No. 18...Light emitting element 19◆・1 Light receiving element 20...Fist magnet patent Applicant Nippon Columbia Co., Ltd. = Bici7-1
N＼ Representative: Satoto Patent Attorney Yamaguchi IJ Bi・(@χ6２. Figure 3 S', N 4 r'! Kazuya A>elW Yu

Claims (1)

[Claims] Take out the disk servo error signal and take it out to a disk player that performs the servo of the original pickup, and check the relative signal between the movable part of the original pickup and the fixed part of the original pickup. : Take out, ``Second servo error 4+, T-boat and mixed waist height 1 dog, the above surf is error-ffj 4 Please make it servo mainly with the loop gain due to 4th! 1.5 characteristics of optical pickup servo, 0