JPS5860439A - Generator for tracking error signal - Google Patents

Abstract

PURPOSE:To generate a high-precision tracking error signal through simple constitution by comparing an electric signal which corresponds to an image on a track with that which corresponds to information light. CONSTITUTION:Light from a laser diode 1 is guided through a splitter 2, a collimator lens 3, a splitter 4, and an object 5 to illuminate a disk 6, thereby reproducing and/or recording information. Information light 1a illuminates a lighting area 7a and its reflected information light and illumination light reaches a splitter 9, and part of the information light and the whole of the illumination light form images on a linear image sensor LIS10. When the information light 1a corresponds to images on tracks T1-T3 in the area 7a, the LIS20 generates a time-series photoelectric output at a prescribed period and sends it to a tracking error signal generating circuit 11. The circuit 11 generates a signal which corresponds to the direction and extent of a shift of the information light 1a from a desired track, and a driving device 12 displaces an optical heat OH in the radius direction of the disk 6.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tracking error signal generating device for a disk memory.

Known disks and memories in which information is optically recorded include playback-only disks such as video disks, RAW disks that can be recorded and played back, and magneto-optical disks that can record, playback, and erase. There is. Also known is a disk memory in which information is recorded magnetically and signals for tracking are optically recorded.

Tracking system 1111 for reproducing information recorded on these discs is performed optically. Taking playback of a video disc as an example, a laser beam spot divided into three parts arranged linearly at equal intervals using a grating is applied to one track.
C. Irradiates at a slight angle. The three beams reflected by the disk are incident on three corresponding light receiving elements. Output t of the light receiving element corresponding to the central beam
Well, as a signal for information reproduction, the outputs of the two receivers and receivers corresponding to the beams on both sides are input to 10 differential amplifiers, and the difference between the two outputs is the tracking error.・The beam in the center of the four-inch signal plane is used to indicate in which direction and how far away the truck is from which information is to be extracted. This method has the disadvantage that it is necessary to prepare two light receiving elements that receive the beams on both sides and have matching dl and sensitivity.

In addition to this, only one beam is sent to the 1* signal track (Kl), and this beam is reflected from the disk (Y, which receives the f-2 split, and is received by both sides) There is a system that takes the output difference between the two and uses it as a tracking error signal, and takes the output 111 of both as an IPt information reproduction signal.In this method, even if the beam is accurately irradiated on the track, the two divided light receiving elements This has the disadvantage that a tracking error signal will be generated if the beam is even slightly deviated from the optical axis.

SUMMARY OF THE INVENTION An object of the present invention is to solve these drawbacks and provide a highly accurate tracking error signal generator with a simple configuration.

To this end, the present invention irradiates an illumination light in addition to the information light used for reproducing or recording information on the disk, and maintains the tracks and information light by the illumination light and receives it by a charging conversion means and converts it into an electrical signal. Then, an electric signal corresponding to the track image and an electric signal corresponding to the information light are obtained from the signal, and both signals are compared to obtain a tracking error signal.

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

FIG. 1 shows a schematic diagram of one embodiment of the invention. This embodiment is a tracking control device FF which is useful when recording information on the above-mentioned DRAW disk and when reproducing information recorded on the above-mentioned DRAW disk. In Figure 1, record the information track 5!1l-
1,1■] A Rehge diode 1 is used as the primary light source. Laser light t, t emitted from here:
, the first beam splitter 2, the collimator 1 nons 3, and the second beam splitter 4 (7) pass through the objective lens 5 to form a minute spot source and irradiate it onto the disk 6. Information is reproduced on the disk 6, and information is recorded on the disk.Hereinafter, this spot light 'f' is referred to as a light source.As a light source for illuminating the disk 6, a light emitting diode T is used. The output nine elements are reflected by the first beam splitter 2, pass through the first beam splitter 3, and pass through the splitter 4 and lens 5 to illuminate a predetermined area on the disk 6. has a different wavelength from the previous tV1r information source.

FIG. 2 shows a portion of the disk 6 that is illuminated by the information light and the illumination light. In the figure, the information light 1a is configured to irradiate the inside of the illumination area 7a. This illumination area 7a has a wide area that includes three adjacent tracks T, , T, , T formed on the disk 6.

The information light and illumination light reflected by the disk 6 pass through the lens 5 again, are reflected by the splitter 4, and then pass through the condenser lens 8.
and reaches the beam splitter 9. splitter 9
The reflectance varies depending on the wavelength, and the lower part of the source is transmitted, while the illumination light is completely reflected. The information light 1a shown in FIG. The information beam 1a is formed as an enlarged image of the illumination area 7a.The illuminance of the information light 1a is also higher than that of the illumination area 7a.

As shown in FIG. 3, LISlo has tracks T1 to T3 where images are formed in the direction of arrangement of the light receiving elements that make up the LISlo.
The light-receiving confectionery is arranged so that the directions of the images thereof intersect with each other, or in other words, the arrangement direction of each light-receiving confectionery coincides with the radial direction of the disk 60. The LISIG repeatedly outputs time-series photoelectric outputs corresponding to the images of the tracks T1 to T in the illumination area 7a and the information light 1a at a predetermined period, and sends them to the tracking error signal generation circuit 11. The circuit 11 receives fk @ 'yt' from the output of ■, 1810,
1 in which direction a is from the desired track and 1 by tL
A signal indicating the deviation by 1, that is, a tracking error signal is generated. The optical head drive kvJL12 displaces the optical head OR, which is composed of the entire series of elements surrounded by a broken line, in the radial direction of the disk 60 in response to this tracking error color type.

The information light transmitted through the splitter 8 is guided to the light receiving element for information reproduction, and is photoelectrically converted there at #21 during use.
This becomes the P8 raw signal.

Next, a specific embodiment of the tracking error signal generating circuit 11 will be described with reference to FIG.

First, a tracking operation for correctly tracing the information light 1a will be described, taking as an example the case where information is reproduced from the track shown in FIG. In FIG. 4, when the reproduction mode is selected, an operation signal 100a representing the selection is sent from the operation means 100 to the control circuit 101. When the circuit 101 receives this, it issues a switching signal 101a and switches between the first and second switches.
Switch the recording/playback switch 102 and 103 to the terminal P for the recording/playback. At the same time, the control circuit 101 receives a signal from the LIS drive circuit 1 from a pulse generator provided in the circuit.
04 is supplied with a clock pulse 101b. The circuit 1
04 sends a start pulse 104a of period T and a clock pulse 104b to LI 810 based on this pulse 101b. The valley light-receiving element constituting LISlo accumulates charges corresponding to the light irradiated onto the photosensitive surface for a period T. That is, as shown in Figure 3,
corresponding to the image of the track T, ~T, by Y4 and the information light 1a superimposed on it, the original output is pulse 1.
041), the disc 6 is scanned from the inner circumference to the outer circumference (from track T to track T) and is output in time series. This original 'row output e' is repeatedly output in the loop j'1' and sent to the 17-C separation circuit 106 via the amplifier 105. The circuit 106 extracts the information light level Il from this photoelectric output.
A 1H rear position ta signal 106a representing # and a track position mar number 106b representing the track position are generated -r.

Figure 5 shows LISIO start pulse 104 m, information source position 18 106 &, 2 and track position multiplication 10
6b shows a timing chart. track position 18
1, sent to the input terminal of the shift register 107 via the switch 102, and the register 107i
1. It consists of three flip-flops equal to the number of tracks projected on LISIG, and as shown in FIG. 5, the track position W! Every time a pulse of the signal 106b is input, the output IQ7a, 107 of the output terminal of each flip-flop
b%107c becomes 11 direct Hi. shift register 1
The content of 07 is the start from LIS drive circuit 104.
It is reset at the period JtJjT by the pulse 104a. Therefore, at that time, all outputs 107a to 105c are off.

become. Outputs 107a to 107c are each sent to a controller 108. At this time, the selector 108 outputs 10 in response to the select signal 101c from the control circuit 101.
One output corresponding to the trunk to be tracked is selected from among 7a to 107c and sent to the rising edge detection circuit 109. Here, the select signal 101c is
It is set to select the output 107b corresponding to the medium-heated truck T2. The rising edge detection circuit 10B has a fifth
As shown in the figure, a target track position signal 109a synchronized with the rise of the output 107b is generated and sent to the negative terminal of the phase voltage converter 110. On the other hand: J110
'l'*<"14")"I-position t+' at the positive terminal of
t 1ifQ 106 a is lost due to human power, converter 110 target track position 1 (19a)
clIl 9th place 11if: Phase difference Δ with 1g No. 106a
An output 110a of LC voltage is generated corresponding to OV. This output 111Ja) is sent to the negative terminal of the difference tm amplifier 111, and input from the 1ltlJ direction 1 circuit 101 to the positive terminal (~
A difference output from the reference signal 101d of C (, +1', 'V] is generated.

This output becomes the tracking error signal 11a.

Returning to FIG. 1, the optical head drive circuit 12 displaces the optical head OH in the radial direction of the disk without this error signal becoming 0 [V], and sends the information light 18 of FIG. 3 to the track T. Correct [7 to make a tonnose. Information light 1a is track T.

10 modulated according to the information recorded in the t
By converting this information light into electricity, a reproduced signal is obtained.

Next, the access operation for tracing an arbitrary track by the tracking error 18 sina generation circuit (12) 11 will be explained.

Here, a case will be described in which the center track Ttk shown in FIG. 6B(1) is accessed, and then the racks separated by n lines are accessed toward the outer periphery of the disk. For this purpose, a command to that effect is input using the operating means 10G.

An operation signal 100 corresponding to the command from the control circuit 101
When a is received, a select signal 101a is sent to the selector 108.
i feed, the output of 107c corresponding to the outer track T shown in FIG. 3 is selected. (When accessing tracks separated in the direction of the inner circumference, the output of 107m corresponding to track T1 on the inner circumference side is selected.) As a result, the tracking error signal becomes O [■].
The optical head OH shown in the figure is moved toward the outer circumference. In response to this movement, the track position signal 106b is changed to 106 in FIG.
b(1) to 106b(5).

Here, only the hatched pulses are extracted and become the target track position No. 1 (19a).
6b (5) t Nidrak T, evening) adjacent to the circumference side,
In 106b(4)'f, the pulse corresponding to the track that was not projected on &; Truck T.

Since the selector 108 selects the output of 107o corresponding to the rightmost pulse at f, the target track position is set to f.
100g of own moon corresponds to the adjacent Udrak on the evening side from Track T. Therefore, the level of the output 110a of the phase voltage converter 110, which had been decreasing by V, is again 22r when approaching the track T, which was initially targeted.
It increases by an amount corresponding to a phase difference of /3. Therefore, the optical head drive/demount 12 continues to move the optical head OH in the outer circumferential direction. This phenomenon occurs every time a new track is projected on the right end of LISlo, that is, every time the ih-shaped head OH is displaced by one track in the outer circumferential direction. In this embodiment, focusing on this, the number of tracks the optical head OH has moved is detected by counting the number of increases in the tracking error signal 11a.

FIG. 7 shows a phase voltage converter output 110a that changes in a sawtooth pattern as the optical head OH moves (this is a tracking signal).
error signal 11a). As shown in FIG. 4, this output 110a is sent to a differentiating circuit 113, which generates an output 113a as shown in FIG.

By the way, the output 110a of the converter 110 shown in FIG.
This is a waveform when the optical head OH is moved toward the outer circumference, and the level increases in the positive direction with each displacement of one track, but when it is moved toward the inner circumference, the level increases in the negative direction. Show change. Therefore, in this case, the pulse of the output of the differentiating circuit 113 also rises in the negative direction.

Returning to FIG. 4, the output of the circuit 113 is sent to a positive/negative pulse (j5) pulse separation circuit 114. The 1lIVh 114 separates positive and negative pulses and sends them to the up/down counter 115 from separate output terminals. Here, the output 113a of the differentiating circuit 113 is sent to the addition input terminal U of the up/down counter 115 as the output 114a of the t'E positive/negative pulse separation circuit 114 since there are all positive pulses 'T'. The counter 115 counts the number of tracks that the optical head OH crosses as it moves toward the outer circumference by multiplying the number of pulses (i-number of sets) of the output 114&.

H1 number output 115a&j of counter 115, 1 sent to 1 song control circuit 101, is this? The receiving circuit 101 compares the desired number of tracks (6) set by the pre-M operation No. 1 1ooa, and when they match, sends the output of the selector 107 to the selector 108.
1010 select signals are sent. Thereafter, the tracking operation described above is performed. The track position 1^' signal at this time is 106b(6) to 1i) in Figure 6.
6 b (9) and 7J<(16). At the time when the position signal 106 b (6) is output, the optical head OH has crossed n-1 tracks. Here, the control circuit 101 causes the selector 108 to select the output 107b corresponding to the center track projected on the LI 810. Therefore, track position signal 1
The optical head OH moves slightly so that the phase difference between the central pulse of 06b(8) and the pulse of the information source signal 106m disappears. When the position signal 106b(9) is output, the information light completely overlaps the center track and the access operation is completed.

Similarly, the control circuit 101 sends a heliset pulse 101e to the counter 115 to clear the count contents when the optical head is returned to the OH position or the innermost circumference of the disk.

Moreover, in reality, the hand value of the counter becomes n +1. This is caused by a rapid increase in the output of the phase voltage converter 110 when the output of the shift register 107 selected by the selector 108 is switched from 107b to 107c at the beginning of the access operation, before the optical head OH is activated. This is because the first pulse of the output 113a of the differentiating circuit 113 was counted. Therefore, the control circuit 101 calculates F' from the count value.
1-1 is subtracted - C is compared with the preset number of tracks 3. As an example of the access video described above, a video signal for one frame is recorded on each concentric track, and nine video discs are recorded. An example of playing back at normal speed will be explained.

In this case, it is sufficient to input to the control circuit 101 an operation signal recorded on the track 7' (displace the head OH by one track in synchronization with the reproduction of the vertical synchronization signal). Each time the optical head OH reproduces nine troughs of information, that is, one frame of video signals, it automatically moves to the next track, thereby realizing smooth video reproduction.

Next, a case will be described in which information is recorded on a DRAW disc in this embodiment. This disk 60 is shown in FIG. 8(a).
A circular reference track 60a as shown in FIG.
A spiral reference track 60b as shown in ) is provided in advance. In this embodiment, information tracks are formed at equal intervals from these reference tracks.

In FIG. 4, when a recording mode is selected, an operation signal 100a indicating the selection is sent to a control circuit 101. Upon receiving this, the control circuit 101 first switches the changeover switch 10.
2. Switching signal 101a for switching 103 to playback terminal P
emits. The optical head OH is initially located at the innermost circumference of the disk 60, but the above-mentioned access operation is started at the same time as the start of the recording operation, and the optical head OH is driven toward the outer circumference. This access operation is performed until the cueing is completed by the configuration described below, that is, until the /C position on the track is accessed. The output 107b of the shift register 107 is connected to the D terminal of the D flip-flop. Further, a clock pulse 101e is sent from the control circuit 101 to the CK terminal.

This pulse 101eid has the same period as the start pulse 104&, but its phase is slightly advanced. Therefore, just before shift register 107 is reset, shift register 1
071) output. 'C, that is, if there is no center track, the output of the D flip-flop is Lol
Become. In the control circuit 101, the output 1 of the D flip-flop
16a gari. The access operation is stopped when the switch 102.10 is turned on by the switching signal 101a.
3 to the recording terminal R. This (the cueing is completed. Information at this time in FIG. 9) is shown as a position signal 106& and a track position signal 106b.

A pulse corresponding to the above-mentioned reference track is generated at the left end (inner circumferential side) of the signal 106b.

With the configuration described below, a virtual 1-stretch track position signal is created based on this track position 11 times number 106b. The track position signal 106b shown in FIG. 9 is sent via switch 102 (20) to some input terminals of AND gate 117 and to the S terminal of RS flip-flop 118. The output 119a of the monostable multivibrator 119 is input to the other terminal of the AND gate 117. This output 11s
& rises in synchronization with the start pulse 104a, and falls after the blue period T of the start pulse has elapsed.

The output 117a of the AND gate 117 is input to the phase-locked triplex oscillator 12G. The oscillator 120 outputs a signal 120a based on the output 117m, which is equivalent to a conventional track position signal as shown in FIG. Since the truth table of this RS flip-flop is as shown below, the output 118 is as shown in FIG.

The output 11B& is sent to the falling edge detection 1 switch 121. The circuit 121 generates a signal 121a (i) which generates a pulse "i<-j" in FIG. '1 (1-1 to u and becomes a virtual target track position signal indicating the position of the first information track to be recorded.

This virtual target truck 14IflLiK number 121a is
The signal 106 is sent to the phase voltage converter 11υ via the switch 103, and the above-mentioned tracking operation
The original head is OH so that the 41-order difference Δθ with m is 1L.
is driven! Sign. The recording preparation is now complete.

Then, the virtual target track'-VC information is written 171 by the information light adjusted according to the information to be recorded.

The intensity of the information light at this time is higher than that during reproduction.

When recording for one track is completed, the number of pulses of the track position signal 106b is 2 per cycle as shown in FIG. 9(h).
It becomes ke. However, the triplex oscillator 120 includes a monostable multivibrator 119 and an AND gate 117.
Because only the pulses corresponding to the inner tracks are input due to the function of , the output 120a of the triple oscillator 120 does not change as shown in FIG. 9(b). Therefore, as shown in FIG. 9(b), the virtual target track signal 12
1a, a rising pulse is generated adjacent to the outer circumferential side of the previously recorded track. This means that a new virtual track has been set.

Then, by the above-described tracking operation, information light is irradiated onto this virtual track, and information recording is performed. The above operations are repeated to continuously record information in units of one track.

Of course, it is also possible to resume recording following the previous recording by the same operation on a disk in the middle of use on which information tracks have been recorded halfway.

Next, another embodiment of the tracking error (23) circuit 11 shown in FIG. 4 will be described with reference to FIG. Description of the same configuration as the embodiment shown in FIG. 4 will be omitted, and differences between the two will be described here. In FIG. 10, the difference between this embodiment and the embodiment of FIG. 4 is that the selector 1
08 is omitted, and the output 1 of the flip-flop in the center is
01b is input to the rising edge detection circuit 109. During the access operation, the control circuit 101 in FIG.
sends a select signal to the selector 108 to select the output 107c or 107a, but instead, the control circuit 101 in FIG. 1O sends the output U in FIG. Select No. 18 is output and a voltage corresponding to a phase difference of 2π/3 or more or 12π/3 or more is input. Here 1. 1, which is completely different from the embodiment shown in FIG.
Next, a specific embodiment of the separation circuit 10'6 will be described.

First, a circuit that uses the intensity difference between the information light and the illumination light (24) to generate an information light position signal and a track position signal will be described with reference to FIG. Preamplifier 10B
The LISIO output 105a via the LISIO is input to the first peak detector 201. This output 105a is the 11th
As shown in the figure, the illumination light component and information light component corresponding to the image of the track appear in a superimposed form. The circuit 201 is
The peak of the signal generated at a level higher than the level of the illumination light irradiated to the LISIO is detected and an output as shown in FIG. 12 is generated. This is the cabinet! Information source location signal 106
It is output as a. The signal 201 is transmitted to a delay circuit 202.
There, it is delayed by the period T of the start pulse 104a minus the half-width of the pulse width of the light component to produce a delayed signal 202! as shown in FIG. It becomes L. The equal image signal generation circuit 203 is connected to this delay circuit 202.
A rectangular pulse with a width equal to the pulse width of the information light component is created in synchronization with the rising edge of the pulse, and this is applied to a delay filter to produce an equivalent signal 2 as shown in FIG. 12, which is equivalent to the information light component.
Outputs 03m. The amplitude of the equal image signal 203a becomes equal to the amplitude of the information light component due to the output of a monitor circuit '204 that monitors the information light intensity. 1: Controlled by the sea urchin 7, this is a 1ft @ playback modulation for recording /
This makes it possible to follow changes in the image of the information source.
-ノ].

The equal image signal 203a is sent to the negative terminal of the subtracter 205. The subtracter 205 subtracts the equal image signal 203a from the light ``Kameyama force 105a'' inputted to its positive terminal and outputs the result.

The output is only the illumination light component corresponding to the image of the track, as shown in FIG. The photoelectric output 205a is the second
to a peak detector 206 of the first
A track position signal 106b as shown in FIG. 2 is output.

FIG. 13 shows another embodiment of the separation circuit 106. This circuit L1 illumination source VC is multiplied by 4 to separate the information light component and the illumination light component, thereby producing an information source position signal and a track position signal.

In FIG. 13, the illumination light source drive surface M301 receives the start signal 104a from the drive circuit 104 and creates an output 301a with a cycle of 'I''r: o N, OFF x repeating as shown in FIG. The illumination light source 7 is all turned on and off.Therefore, the preamplifier 105 of LI810
As shown in FIG. 13, the output 1051 through the 1051 includes a period in which the information light component and the illumination light component corresponding to the track pattern are superimposed, and a period in which only the 41a original component is present, alternating with a period T. appear. This output 105a is input to a one-period delay circuit 302. The circuit 302 has an output 105
Output 3 where a is delayed by a period T as shown in FIG.
02a, and connect the positive terminal of the subtracter 303 and the selector 3υ4
into some input terminals. The output 105a is input to the negative terminal of the subtracter 303 and the other input terminal of the selector 304. Therefore, the subtracter 303 generates an output 303ai shown in FIG. The inverter 305 creates a sign-inverted signal 3Q5a that repeats sign inversion in the same phase as the output 303a, as shown in FIG. 14, and multiplies it by 303&. As a result, the sign inverter 305
As shown in FIG. 14, continuous illumination light components are generated based on the output 301a from the first peak detector 3.
Send to 06. From the 0 detector 306, the graph shown in Figure 14↓
A song/track position signal 106b is output.

- 10,000 selector 304 t;jl is switched by loop IT by the output 301a of the drive circuit 301, alternately selecting the output 302m and the output 105a during the period in which only the information light component appears, and outputting it to the second peak detector 307 send to The detector 307 outputs an information source position signal 106m as shown in FIG.

Next, a further example will be described in which the information light component and the illumination light component are separated by utilizing the fact that the wavelengths of the two are different.

(28) Referring to FIG. 15, the LI8400 receives information light and illumination light from the disk in the same way as the LI810 described above. 1L
In the Is400, a light receiving element 400 & whose light receiving surface is provided with an optical filter that transmits only information light, and a light receiving element 400b whose light receiving surface is provided with an optical filter that transmits only illumination light are arranged alternately. .

FIG. 16 shows a circuit for obtaining information light components and illumination light components from LI8400. In the same figure, LI84QQ
is driven by the clock pulse and start signal from the drive circuit 401 in the same manner as the LI81G described above.

The output of LI840G is input to first and second sample and hold circuits 402, 403 via a preamplifier. The circuits 402 and 403 are connected to the LI from the drive circuit 401.
It is driven by two clock pulses that have half the period of the clock pulse sent to the 840G and are 180° out of phase with each other, and each light-receiving element 4 (J O
Alternately sample and old the outputs of a and 41) Ob. , thus the first and second sample old circuits 402
．． From 403, continuous information light components and illumination light components are obtained. , these are input to the first and second peak detection circuits 404 and 405, and outputted as the information source position signal 106m and track position signal 106b.

The LIS 401 shown in FIG. 17 receives information light and illumination light from a disk like the LI810 described above, and is provided with an optical filter that transmits only the information light.
and an optical filter that transmits only the illumination light 4
01b. According to this, LI840
An information light component is directly obtained from 1a, and an illumination light component is directly obtained from 401b.

In FIGS. 17 and 18, a four-element photodiode array 300 is used in place of the LI 810, and from this output not only a tracking error signal but also a sensitive axis reproduction signal that is necessary to keep information flowing is obtained. 9'll is shown. FIG. 17 shows a state in which the information light 1a is correctly tracked onto the track T. As can be seen from the figure, the array 300 and the information light source 1 are arranged so that the information light always illuminates the first and second photodiodes 30011 and 300b with equal visibility. The first and second photodiodes 300 are properly tracked.
The optical image of the track T1 is on the a and 300b, and the optical image of the track T2 is on the second and third photodiodes 300c and 300d.
The setting is such that each light image is irradiated with the same amount of light. In FIG. 18, first, the tracking operation during reproduction will be explained. When the playback mode is selected, the first
and the second changeover switch 601.602 is the playback terminal P.
can be switched to The photoelectric output of the first photodiode 300& is connected to the first preamplifier and the first selector switch 60&.
1 to one input terminal of the first and second adders 6016o4.

(31) The source 11f of the second photodiode 300b, the output is connected to the amplifier 1ii1 before #g2 and the second changeover switch 60
The other input terminal of the first adder 603 and the third
It is sent to one input terminal of adder 605. The output of the third photodiode 14300C is sent to the other input terminal of the second adder 604 via the third preamplifier, and the output of the fourth photodiode 3UOd is sent to the other input terminal of the second adder 604 through the third preamplifier. The second adder 604, which is sent to the other input terminal of the third adder 605 via an amplifier, adds the light weight outputs of the first and second photodiodes 300a and 300o, and converts the output into a band band. Send to bus filter 60G. The filter 606
Since the illumination light is modulated in a band of about 10 KHz, it is provided to pass only signals in this band.

The output of the band pass filter 606 is sent to the positive terminal of the differential amplifier 608 via the first detection circuit 60''1.

The third adder 605 connects the second and WJ3 photo (32) and diode 30. The photoelectric outputs of Ob, , 3QQa are amplified, 7 and summed, and the output is sent to a band pass filter 609 similar to the band pass filter 606.

The output of the filter eOq is sent to the negative terminal of the differential amplifier 608 via the second detection circuit 610. Therefore the 17th
As shown in the figure, when the information light 1a correctly traces the track T, the output of the time difference v1 amplifier 608 becomes 0,
The level and polarity of its output changes depending on the amount and direction of the tracking error.

The first adder 603 adds a signal band (for example, 1
It operates at 2 MJ(z), amplifies and adds only the photoelectric output of the information light, and outputs it as a reproduced signal.

During reproduction, in this embodiment, two photodiodes are assigned to each of two tracks to obtain a tracking error signal, so that tracking error detection sensitivity is high.

Next, the tracking operation during recording will be explained. When the recording mode is selected, the first and second selector switches 60
1, θ02 is switched to the recording terminal R. This is 1
llii and second photodiode 300a, 30
The photoelectric output of 0b is utilized 1. Therefore, the -C tracking error signal is the difference in the outputs of the second and third photodiodes 3ooc and 300d, and when both the forces match, tracking is complete.・From the track T, where the diodes 300c and 300d receive the illumination light, to the outer circumference (this is the case where the track is formed from the inner circumference to the outer circumference, and in the opposite case, the track is formed from the inner circumference to the inner circumference) 41'? information modulated according to the information to be recorded at a location separated by one track) is irradiated, and a new information track T2 shown by hatching is formed.

2nd and 3rd photodiode t'3000°300d
Since the distance V between the track T and the information i1a is always constant, new tracks T are always formed at equal intervals even if the track T is shaken due to eccentricity.

As described above, according to the VC of the present invention, a tracking error signal generating device with a high f# degree can be obtained with a 111ji rate configuration.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an embodiment of the present invention, FIG. 2 is an explanatory diagram showing tracks on a disk, illumination light and information light irradiated thereon, and FIG. 3 is a diagram showing a photoelectric conversion means and FIG. 4 is a block diagram of the tracking error signal generation circuit of the same embodiment; FIG.
7 and M9 are diagrams showing timing charts of various outputs generated by the tracking error signal generation circuit, FIG. 8 is an explanatory diagram of a disc before recording with a reference track provided, Fig. 10 is a block diagram showing another embodiment, Fig. 11 is a block diagram of the separation circuit of the embodiment shown in Fig. 10, and Fig. 12 shows the timing and timing of each extraction power of the separation circuit.
FIG. 13 is a block diagram of another embodiment of the separation circuit, FIG. ll indicating the conversion means
(?, clear figure, FIG. 16 is a block diagram of a separation circuit suitable for photoelectric conversion means, FIG. 17 is a diagram showing still another photoelectric conversion stage, and FIG. 18 is a diagram of a photoelectric conversion circuit in another embodiment of the present invention. FIG. 19 is an explanatory diagram showing a converting means, a track formed thereon, and an image of information light; and FIG. 11 is a block diagram of the same embodiment.
, [Explanation of symbols of main parts] 1.2.3.4.5...) 1. Cutting thread 1.2.3.4.5... Information system 4.5.89... Imaging Optical thread 10...Photoelectric conversion means 11...Tracking error signal generation circuit (36); t-5 figure 6 figure off figure 8 figure (α) /l=q figure ((1)

Claims (1)

[Scope of Claims] 1. An illumination system that irradiates illumination light onto a predetermined area of a size that can include tracks provided on the disk surface; and an illumination system that irradiates illumination light to a predetermined area that is large enough to include tracks provided on a disk surface; an information system that illuminates a part of the disc; an imaging optical system that projects both the illumination light and information light from the predetermined area of the disk onto a photoacoustic imaging plane; a photoelectric conversion means for converting the track in the disk radial direction obtained by the illumination light and the image of the information light into an electric signal I/C; an information light component corresponding to the image of the information light and the track from the output of the conversion means; The illumination light component corresponding to the image of ? Then, by comparing all the image components, a tracking error signal is outputted corresponding to the distance from the current flit projection position of the information light to the L1 target 1a'(ri) in the illumination area. 41 error signal generation circuits are 1II8 features. (a) Dragging error signal generation device + 1N. 2. The photoelectric conversion means outputs the curved illumination light component and the information component in a time-series manner in an integrated form, and the tracking error signal generation circuit converts the illumination light component and information from the time-series output. A phase difference detection circuit that detects the phase difference between one image component and fj.
Tracking error (bar@'uhe generation device) according to claim 1, characterized in that the photoelectric conversion means includes a first light receiving section that is sensitive only to illumination light, and a tracking error that is sensitive only to illumination light; The tracking error signal generation circuit generates a quaternary component from the output of the first light receiving section and a four-dimensional component from the output of the second light receiving section. 2. The tracking error signal generating device according to claim 1, wherein the tracking error signal generating device obtains the respective components.