JPS58211370A - Tracking servo signal generator of information reader - Google Patents

Abstract

PURPOSE:To eliminate completely noise components due to the shift of an optical axis, etc., by using only the high band component of a tracking information signal to perform so-called in-phase wave detection and then generating a tracking servo signal. CONSTITUTION:The outputs of amplifiers 10a and 10b which amplify the outputs of photoelectric transducers 9a and 9b are applied to an adder 17 and a subtractor 18. These addition and subtraction outputs are turned into the output of a multiplier 20 via an HPF19a and HPF19b respectively. This output of multiplication is applied to an equalizer 13 via an HPF21 and then amplified by a driving amplifier 14 to be used to a driving signal of a coil 8.

Description

[Detailed description of the invention]

The present invention relates to an information reading device that has an optical information reading device.
- As a green control I device - (Figure 1 (2) There is a small configuration 1, that is, a ray light source 1J, the irradiation light is a lens 2, a beam snoritter 3.1'
The 4-wavelength root 4BC and the objective lens 5) are incident on the recording surface of the optical disk 6 (6). Minute <(Information detection point-(big 7/tsu/optical tube l'
Knee'%ru,. The reflected light (X is transmitted light) by this 1" iscro is separated by a beam splitter 3 (the combination of the beams is converted into a conversion system r9
3° double-likelihood electric conversion element i irradiated in each light receiving direction l of a and 9b
The outputs of '-9a and 9b are amplified by 10a. 10b and LPt<++-Pasno Cruta) 1 'l
il. 1' lb is applied to the differential amplifier 112 via the signal line. 1 This IT output is input to the drive knob 1/I via the E1 relay 13, and knocks the objective lens 5 to 1 II'I.
Drive 11 of Ile 8 to avoid moving in the father's direction
No. 1-JT is here. The silk light conversion wood 9a, 9b is attached as shown in Fig. 2 (-small book dividing line 9c1. is a record
~ knock tangent direction (- arrow Y - (indicated) - (is) Ill, and with respect to the optical axis 7- of the reflected light of the light spot

[These threads r≦] a and gb are set so that they are symmetrical. 1. 7C is the optical axis of the incident light, and 15 is the spin wheel for rotating the disk. . Figure 3 shows "Iscro 1 record 1 to 16-1.16-2.16-3 and information detection di)
The relationship between the light spot S (Ill) and the light spot S (I) is shown below.Then, the center of the spot StJ is aligned with the pitch I, and along the center line 10 of the recording track, the center line 10 of the recording track is t[).
Figure 4 (A) shows the output horn waveforms (A) and (+1) of the amplifiers 10a and 10b, which have a predetermined relative darism (when they are moved sequentially from 1 to the right in the drawing). (B) These two waveforms (A) are shown in Figure 4 (Δ>, (C) and (-) in (B)). Therefore, at this time, the output of the difference #1 IJ7 and 12 becomes zero level as shown in (e) of Fig. 7, indicating that there is a running error and that accurate switching has been carried out. Next, the cause of the tonnage shift due to the eccentricity of the recording track is J, the center of the light spot knocks to 1, -++ cross direction (X > 5) ”,)(,
゛, this is d>-> on the dotted line 11, i/J in the drawing.
When moving in the direction l\, the output waveforms of 7/amps 10a and 10b (a) and (1'l) are shown in Fig. 5 (△) and N ().
i, - people's small (a), (II> like <' (Nru. 1) Both of these waveforms (a), ([1) I-, pH1a, 1
lb to R1, Deno J (,1 people 5th) Figure (A), (]3
) of (c), (-) k: (1), 1, so the difference vJ/amplifier 12 output has (-'l pole ↑ f of 11) −)−I? 1S2 or 1 no. -No, the center of the light spot is the dotted chain line S- in Figure 3.
If you turn to the X direction, follow the dotted chain line 1, and move to the right in the drawing, /Jino 10a. Each output waveform of 10F+ is (A), (I]) in Fig. 0 (△), (+3)! The output of both waveforms through IPFlla and iqb is as shown in Figure 6 (A), (B) (c), () 2, 3
J, )-(differential) The output of the I-sib 12 is as shown in FIG.
), 1] Gokutake's 1 Noi Masashi J is obtained. As can be seen from the above, the output of the X-movement/shaft 112 shows that the center of the optical pickup slot 1 is recorded i~sonok 14\line 10t and the center + [! 1/J direction
Depending on whether it is biased or not, take the negative electrode bamboo,
It takes a size that corresponds to the amount of 11Ii of IJi (i'
;;'r is digitized by 1, so this becomes Tonotsungri~hoshinB (゛). In such a TRATSU A~nguribo IS 舅 generator, 41ii is created as shown in 1 below. −) light weight °
It is necessary to arrange the light-receiving surface of the dust replacement tree f'9a, ≦)b exactly 1F symmetrically with respect to the optical axis 7'-L2, and to
However, it is very difficult to install it exactly symmetrically.
... due to the displacement of the optical axis 7 due to the touch of J'iscro (the symmetry of the beam becomes worse, and at this time even if the pick 1 tube 1- optic axis 7- Even if it is done correctly, the outputs of 11a and 11b are not equal, and as a result, there is a drawback that a small deviation occurs in the Gribo system. The purpose is to prevent adverse effects on the TRAF 1-GREEBO No. 15 caused by the symmetrical deviation of the light-receiving surface or the deviation of the optical axis. ]J
Providing capable Tonok1 Green Elementary School 4I, Father-in-law 1 device T16
(-Toguru. 1-Function 1 by A invention) The small lit Sj-11 device is the pick 7 l information detection point tip ll'
Δ is generated between the detection horns corresponding to the amount of deviation Jj in the 4-cross lJ direction. Difference between the high-frequency components of the detection output of the - set of detection means installed in J.
The difference between the sum signal of the high-frequency components of the detection output of the first stage of No. 1 and the detection output of the first stage of detection of this set (corresponding to the phase Δ of No. ii)
Corresponds to the difference signal level of cl if the polarization is on the right side.
Light 11 signal to read the novel! The present invention will now be described with reference to the drawings. Figure E3 is a circuit diagram of an embodiment of the present invention. 'I]-0 month J, shown ♂ (Explanation for Jj is omitted. The output of each photoelectric conversion element 9a, 911 is amplified 4
The respective outputs of the 77 modules 10a and 10b are added to an adder 17 and a reducer 18. The sieving output is 111)
l' (bypass noise filter) 19a, and the subtracted output is II + It is applied to noisers 1 and 3, and this is the driving noise /'
4c is amplified by 1/l. Figure 9 (△) is smaller in Figure S3)
, :The spot So is fixed to the recording center line 10 and moved to the right of the drawing l\e? Ru. The output waveform of the adder 17 for &i is shown below. The output of this 7111 Ell device 17 is determined by the influence of the asymmetrical t!1 of the light receiving 1 (1) a, 9b or the deviation of the optical axis 7'. Direction X perpendicular to center line 1-0
The change in the waveform of the output of the adder 17 when the dotted line [I or 1-4 in FIG. 3 is shifted is ignored. Figure 9 (13) shows J [
The light spots S0 and S- of the output waveform of the letter reducer 18 (the waveforms of the dotted line and the dashed-dotted line are shown in FIG. !, 2 cases are small 1. In addition, the light spot light source is]
The output of the attenuator 18 in the case of 11 scales when the knock center line is moved from 0 is naturally at a certain level. Subtractor 1 in the case where the dividing line 9C deviates in the substantially orthogonal IJ direction.
8, and the waveforms of the dotted line, +:, and one-dot chain line are approximately the same as those shown in Figure 3 () where the light spots SL and S- move along the dotted line [-1 and one-dot chain line]-1. - Keep the amount small. The solid line in Figure (C) indicates that the optical spot SO moves along the center line 101 and the /cvA combination (with, the output of the reducer 18 corresponds to the displacement of the optical axis 7') CA noset α are superimposed, and this A route α is a miscellaneous component due to the deviation of the optical axis 7'. Next, refer to FIG. 10. 11P of the tightening force) = 19.3 is red (ir +-; waveform (・There is. Figure 1 (13) is 1 of the reducing output of the reducing device 1E3.
11) Signal waveform after +19b (with P, It P l
”19 Due to the action of b, there is a noise component [・some D CA
) Shitsu 1 ~ α or excluding, it is I this b and Jjsr:
, <Line, J: , on the dashed line and solid line (11, +f axis) are the dotted line 2 in Figure 9 (O). is Tokiki 20
``,'', the output waveform of the Tohoku bomb (・Similarly, the white line, dashed-dotted line, and solid line correspond to the waveforms of each line in the same figure (13). , (1) I-21 of this multiplied Q output The waveform of the /Ji month becomes as shown in Fig. 10 (1)〉, and the 1F definite tJ, l-not (leg 1 no change month and 4) are respectively similar to the example of Fig. 7 and 11+1 If we convert d7, we can add a small amount to Figure 10 (A). Depending on the direction of deviation of the light spot in the direction x, there is an in-phase or G, L anti-phase relationship, and the high frequency component level of the subtracted output should be proportional to the polarization (6+ amount) of the optical spora I. Therefore, so-called in-phase detection is performed by the multiplier 20 and 1F) F-21.In other words, if the two multipliers 20 are in the same phase, The output of 11 1-21 is 11 pole bamboo (dotted chain line)
If the phase is in the opposite phase, the polarity becomes negative (dotted line), and the absolute value level (proportional to the deviation φ (a certain 3°) (,1ll) l'10; 0
J in Figure (1), A to shape the waveform into a square wave.
I conversion 17, due to this 9J1 type wave I-I P r 19
Similarly, the multiplication result can be obtained by converting the output of b to If this square wave is used as a guide, the level of the beam will be electrified, so even if there is a fluctuation in the L-novel of the excitation output of the adjuster 17 due to the deviation of the optical axis L, it will always be possible to obtain an accurate tone. 1 ng 1 no 1
, No. 1 is 1! The structure of the Toppu device 20, 1.
, 1゜ which can be easily hit by using the r-jing circuit, :, other /j? A is tlt) 119a
1 and the negative peak of the +1 sinusoidal output of 1c11 and the output of Ill'119b are held in place, and the difference between the two vehicle and rut outputs is determined to be exactly the same. In addition, 1ilj!Example-(-44 Information detection point one-way closing means (using objective lens b) (but using other means such as so-called 1 ohms and 3L optical type) Other examples include the electrostatic method.
・According to the present invention, as described in 1.
Using only the acid component (so-called 1 [J1 phase detection)
It is possible to completely remove the low frequency miscellaneous components caused by optical axis misalignment etc.
1゜ when Green Bore a+ control becomes i+J function

[Brief explanation of drawings]

Fig. 1 is a diagram of a conventional Tono21 Gribo device, Fig. 2 is a diagram showing the relationship between the recording surface of a light spot 1 for information detection and the light-receiving element, and Fig. 3 is a diagram of the recording
-") A diagram showing the relationship between the pitch I/rows and the light spot that make up the block, and Figure 4, Figure 7, and Figure 1. The figure shows a block diagram of an embodiment of the present invention.
-1 tsuk figure, ';: A9 figure and figure 10 are 10 of figure 8.
Waveform diagram explaining the dynamics of Tsuku (there is.
Screen 7...Record no r Screen 9...Photoelectric conversion thread f]7...Adder Q unit 133...Reducer 19... 1ll) + 20...
Toki 21...11) 1 Applicant Bai A-no' stock + (Kai, ?, I agent)
Burri 1 Gravel) Shi 1'↓382

Claims (1)

[Scope of Claims] (1) Pick point/information detection) The information detection point is biased in one direction substantially orthogonal to the recording mark so as to accurately track the recording mark; Ta1~
Notes 1 Green small control device Noribo f + 2 (for detection of the above-mentioned - set of detection f stages, such as J = 'l +, '- installed I, - silk detection f stage, etc., where a difference occurs between the detection outputs)) y] The difference between A,) and (phase; −
No signal is emitted by Lee Hoi 4, 8 shots/1 device, which has a local/14th stage. (2) Said 1 no (1st stage from F1 is the said phase I L month and said 7
3) Said 1 no (+j bow light "dan [yo said phase i J,
A rectangular wave based on the number (a ”5 ago, written A (!i 5
Multiply 4 by 0 and remove the Azuma Nishikiki, and take this Toshin output as the 1 no IC + bow and 1] (I, 1 item range, the Riboi 91 month generator described in item 1. ) The information detection 1.', ζ are light spots (with,
Detection of the set - 1st stage Claims 1, 2, or 3 are arranged in the tangential direction (J), and the recording surface of the light spot is irradiated with light onto the light-receiving surface. Noriichi Kozogo'g:,':L device.