JP2522634Y2 - Optical pickup - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Industrial Field of the Invention The present invention relates to an optical pickup, and more particularly to irradiating an optical recording medium such as a compact disk player or a magneto-optical disk device with a light beam to record or reproduce desired information. This is suitable for application to the optical information processing apparatus described in FIG.

B. Outline of the present invention In the present invention, the whole configuration can be simplified by time-division multiplexing and outputting the servo output signal in the optical pickup.

C Conventional Art Conventionally, in a compact disk player, a plurality of photodetectors are arranged on one optical pickup substrate to constitute an optical pickup.

That is, in FIG. 3, reference numeral 1 designates an optical pickup of a compact disk player as a whole, which is formed on a single substrate by integrating the entire optical disk, and an optical disk together with an objective lens, a semiconductor laser and the like. Is held so as to move in the radial direction.

The optical pickup 1 divides the square area 2 into two equal parts in the vertical and horizontal directions, and outputs four output light detecting elements 2A proportional to the amount of incident light in each area.
2B, 2C and 2D are formed, and each photodetector 2A, 2B, 2C and
An output signal obtained from the 2D is output to the signal processing circuit 4 on the signal processing circuit board side via buffer circuits 3A, 3B, 3C and 3D, which are current-voltage conversion circuits.

On the other hand, the addition circuit 5 includes the respective photodetectors 2A, 2B,
And the output signal obtained from the 2D, and outputs the added signal obtained through the buffer circuit 6.

Further, the optical pickup 1 has sub-light detection elements 8 and 9 formed with the square area 2 interposed therebetween, and outputs an output signal obtained from the sub-light detection elements 8 and 9 by a current-voltage conversion circuit. The signal is output to the signal processing circuit 4 via the buffer circuits 10A and 10B.

On the other hand, in the compact disc player, the main and sub light beams reflected by the optical disc are condensed through an objective lens (not shown), and the square area 2 and the sub light detection are performed. The optical spots SP0, SP1, and SP-1 are formed on the elements 8 and 9, and the output signals S _A ,
For S _B , S _C and S _D , the following equation: S _Y = (S _A + S _B ) − (S _C + S _D ) (1) S _X = (S _A + S _D ) − (S _B + S _C ) ... (2) The position signals S _X and S _Y are obtained and the position signals S _X
And S _Y to adjust the irradiation position of the light Supotsuto SP1 so that 0 level.

If the irradiation position of the optical spot SP1 is adjusted so that the output signals S _X and S _Y become 0 level, the optical spot SP1 is adjusted.
Can be formed at the central position between the light detection elements 2A, 2B, 2C and 2D. In the signal processing circuit 4, the following equation is obtained: S _FE = (S _A + S _C ) − (S _B + S _D ) (3) by obtaining Fuo Kas error signal S _FE, it is configured so as to be able to detect the defocus amount of the main light beam relative to the optical disc.

Thus, by driving the objective lens based on the Fuo Kas error signal S _FE, it is adapted to Fuo Cast Raţ King.

In the output signal S _RE obtained via the buffer circuit 6 contrast, is given by: _{S RE = S A + S B} + S C + S D ...... (4), thereby in accordance with the presence or absence of pits signal A reproduction signal _SRF whose level changes is obtained.

Further, for the output signals S _E and S _F obtained via the buffer circuits 10A and 10B, a tracking error signal S _TE of the following equation S _TE = S _E −S _F is obtained. obtained by detecting tracking error of the main light beam with respect to the recording track on the optical disc, by driving the objective lens based on the tracking error signal S _TE,
It is designed to obtain a state of just tracking.

D Problems to be Solved by the Invention By the way, when the position signals S _X and S _Y , the focus error signal S _FE and the tracking error signal S _TE are obtained in addition to the reproduction signal S _RF as described above, must output from the optical pickup 1 7 output signals S _RF and S _a to S _F, a problem has been made to wiring between correspondingly the optical pickup and the signal processing circuit board is complicated.

The present invention has been made in view of the above points, and is to propose an optical pickup which can simplify the wiring between the optical pickup and the signal processing circuit board.

E Means for Solving the Problems In order to solve such problems, in the present invention, a plurality of light detecting elements 2A, 2B, 2C, 2D, 8, 9 and a plurality of light detecting elements 2A, 2B, 2C, Output signal output from 2D, 8, 9
_{S A, S B, S C} , S D, S E, and calculation means 5 generates a reproduced signal S _RF from S _F, and outputs the reproduced signal S _RF via the first signal line to the outside, the A counter circuit 22 that counts according to count operation signals S _CK and S _RST input from the outside via the signal line 2 and sends out a count output signal as a signal selection signal; and a plurality of photodetectors 2A and 2B. , 2C, 2D, 8,
9 among the output signals S _A , S _B , S _C , S _D , S _E , and S _F to obtain at least a focus error signal and a tracking error signal. Time-division multiplexed signal by selecting
And a selection circuit 24 that outputs the signal to the outside through the signal line.

F action The output signals S _{A of} the photodetectors 2A, 2B, 2C, 2D, 8, 9
A reproduced signal _SRF is generated and output from S _B , S _C , S _D , S _E , and S _F and output signals S _A , S _B , and S 9 of the photodetectors 2A, 2B, 2C, 2D, 8, 9 are output. _{S C, S D, S E} , among the S _F, division multiplexing and output time based on the output signal to obtain at least Fuo Kas error signal and tracking error signal to the clock signal S _CK. Thus, the number of wirings drawn from the optical pickup can be reduced, and the optical pickup can be easily configured.

G Embodiment Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

(G1) First Embodiment In FIG. 1 in which parts corresponding to those in FIG. 3 are assigned the same reference numerals, reference numeral 20 denotes a compact disk player as a whole, and a light pickup 21 to each of the light detecting elements 2A, 2B, 2C,
2D, 8 and 9 output signals S _{A to} S _F are time-division multiplexed and output.

That is, the optical pickup 21 is entirely integrated into an integrated circuit, and the optical pickup 21 itself is a focus error signal.
By driving based on S _FE and tracking error signal S _TE, it is adapted to tracking control.

Further, in the optical pickup 21, a counter circuit 22 is provided.
The clock signal output from the signal processing circuit board 23 side
Giving S _CK and reset signal S _RST, the clock signal S _CK
And based on the reset signal S _RST it is made to sequentially cyclically switches the contact point of the selection circuit 24.

As a result, the output signals S _{A to} S _F are time-division multiplexed via the selection circuit 24, and the signal processing circuit board is supplied via the buffer circuit 25.
It is designed to output to the 23 side.

In practice the reproduction signal S _RF, the reproduction signal S frequency band of several tens [MHz] to reproduce the recorded data from the _RF contrast is required, Pojishiyon signals S _X and S _Y, Fuo Kas error signal in S _FE and tracking error signal S _TE, as long obtained even frequency band of several [k Hz], it is possible to control a practically sufficiently the optical pickup 21.

Therefore, in this embodiment, by sequentially switching the contacts of the selection circuit 24 at a frequency of 100 [kHz], the output signals S _{A to} S _F can be converted to a signal processing circuit board 23 in a practically sufficient frequency band.
Output to the side.

In this way, the number of wires between the optical pickup 21 and the signal processing circuit board 23, which is conventionally required seven as a whole, can be reduced to four, and a compact disk player 20 having a simple configuration can be obtained as a whole.

In particular, in this embodiment, the optical pickup 21 itself have been made to drive based on Fuo Kas error signal S _FE and the tracking error signal S _TE, between the case where the optical pickup 21 and the signal processing circuit board 23 If the number of wirings is reduced, not only can the overall configuration be simplified, but also the drive of the optical pickup 21 can be facilitated.

On the other hand, in the signal processing circuit board 23, the time-division multiplexed output signal output from the optical pickup 21 is received by the switch circuits 29A, 29B, 29C, 29D, 29E and 29F.

Switch circuit 29A, 29B, 29C, 29D, 29E and 29F sequentially switches the contacts in response to the control signal S _C1 output from the counter circuit 28, thereby to switch the contacts cyclically in synchronism with the selection circuit 24 The switch circuit
By outputting the output signals of 29A, 29B, 29C, 29D, 29E and 29F to buffer circuits 31A, 31B, 31C, 31D, 31E and 31F having hold capacitors 30A, 30B, 30C, 30D, 30E and 30F, respectively. , Each photodetector 2A, 2B, 2C, 2D, 8
And 9 output signals S _{A to} S _F are demodulated.

Thus, in this embodiment, the adder circuit 5 includes the output signals S _A , S _B , and the output signals of the plurality of photodetectors 2A, 2B, 2C, 2D, 8, 9.
While S _C , S _D , S _E , and S _F constitute an arithmetic means for generating and outputting a reproduction signal _SRF , the selection circuit 24 includes a plurality of photodetectors 2A, 2B, 2C, 2D, 8, 9 output signals S _A , S _B ,
A time division multiplexing means for time division multiplexing S _C , S _D , S _E , and S _F and outputting the result.

According to the above configuration, each of the photodetectors 2A, 2B, 2C, 2D,
The optical pickup 21 and the signal processing circuit board 23 are output by time-division multiplexing and outputting the output signals S _{A to} S _F 8 and 9.
The number of wires between them can be reduced, and the compact disc player 20 having a simple configuration can be obtained as a whole.

(G2) Second Embodiment In FIG. 2, reference numeral 30 denotes a compact disk player as a whole, which converts a time-division multiplexed output signal output from the optical pickup 21 into a digital signal and processes it. It was done.

That signal processing circuit in the substrate 33, the time division multiplexed output signal in synchronism with the clock signal S _CK receives the analog-to-digital conversion circuit 34 adapted to drive, the register circuit 35A and the output signal, 35B, 35C, 35D,
Give to 35E and 35F.

Register circuit 35A, 35B, 35C, 35D, 35E and 35F, in accordance with a control signal S _C2 output from the control signal generating circuit 36, takes in the output signal of the sequential analog-to-digital in synchronization with the selection circuit 24 conversion circuit 34 The output signal is output to the control circuit 37.

The control circuit 37 is composed of an arithmetic processing circuit and generates the position signals S _X and S _Y , the focus error signal S _FE and the tracking error signal S _TE , thereby controlling the optical pickup 21. .

Actually, in this kind of compact disc player 30, focus control and tracking control are performed by using an arithmetic processing circuit. In this case, the outputs of the respective photodetectors 2A, 2B, 2C, 2D, 8 and 9 are output. By time-division multiplexing and outputting the signals S _{A to} S _F , the time-division multiplexed output signal can be converted into a digital signal only by being supplied to one analog-to-digital conversion circuit 34, and the entire signal can be converted accordingly. The configuration can be simplified.

According to the above configuration, in addition to the effects of the first embodiment,
The digital signal can be converted by one analog digital conversion circuit 34, and the overall configuration can be further simplified.

(G3) In other embodiments noted above embodiment has dealt with the case of driving on the basis of the optical pickup 21 itself Fuo Kas error signal S _FE and the tracking error signal S _TE, the present invention is limited to this Instead, the present invention can be applied to a case where tracking control is performed by driving an objective lens.

Further, in the above embodiment, the buffer circuits 3A, 3A
Although the case where the output signals of B, 3C, 3D, 10A and 10B are directly output to the selection circuit 24 has been described, the present invention is not limited to this, and the buffer circuits 3A, 3B, 3C, 3D, 10A and 10B and the selection circuit A sample-and-hold circuit may be interposed between the 24, so that noise can be reduced in the time-division multiplexed output signal.

Further, in the above-described embodiment, the frequency is 100 [kHz].
In the above, the case where the contact of the selection circuit 24 is switched has been described. However, the present invention is not limited to the frequency of 100 [kHz], and may be switched at a desired frequency as needed.

Further, in the aforementioned embodiments, it has dealt with the case of switching contacts sequentially and cyclically selecting circuit 24 outputs the clock signal S _CK and reset signal S _RST to the optical pickup 21, the present invention is not limited to this, For example, the address data may be sequentially output to the optical pickup, and the output signals S _{A to} S _F specified by the address data may be output.

In this way, the output signal S _A at a desired interval
It can be time division multiplexing to S _F. Further output signal
Of S _{A to} S _F , only the required output signal can be selectively obtained.

Further, in the above-described embodiment, the case where the present invention is applied to the compact disk player has been described. However, the present invention is not limited to this, and for example, like the optical pickup of a magneto-optical disk device, the auxiliary light detecting element 8 and 9 is composed of two light detecting elements, and a light pickup for recording or reproducing desired information by irradiating a light beam to an optical recording medium such as a tape or a card. It can be widely applied to optical pickups of information processing devices.

H Effects of the Invention As described above, according to the present invention, a reproduction signal is generated and output from the output signal of the photodetector, and at least a focus error signal and a tracking error signal among the output signals of the photodetector are output. The output signal for obtaining the signal is time-division multiplexed based on the clock signal and output, so that the number of wirings between the optical pickup and the signal processing circuit board can be reduced and the configuration of the optical pickup can be simplified.
Thus, the optical pickup can be further reduced in size.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a compact disk player according to an embodiment of the present invention, FIG. 2 is a block diagram showing a second embodiment thereof, and FIG. 3 is a block diagram showing a conventional compact disk player. 1, 21 ... optical pickup, 20, 30 ... compact disc player, 2A, 2B, 2C, 2D, 8, 9 ... photodetector, 3A, 3B, 3C, 3D, 6, 10A, 10B, 25 ... ... Buffer circuit, 5 ... Addition circuit, 22, 28 ... Counter circuit, 24 ...
Selection circuit.

Claims (1)

(57) [Scope of request for utility model registration] 1. A plurality of photodetectors, and a calculation means for generating a reproduction signal from output signals output from the plurality of photodetectors and outputting the reproduction signal to the outside via a first signal line. A counter circuit for performing a count operation based on a count operation signal input from the outside via a second signal line and transmitting a count output signal as a signal selection signal; and the output output from the plurality of photodetectors The output signal for obtaining at least the focus error signal and the tracking error signal among the signals is selected by the signal selection signal, so that the time-division multiplexed signal is output to the outside via a third signal line. An optical pickup characterized by comprising a selection circuit for outputting.