JPH1139672A - Optical disk device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical disk device capable of reducing the deterioration of a signal by using a small and thin optical pickup and a conventionally used RF amplifier. SOLUTION: An optical pickup 111 outputs an RF signal from a light receiving element 10 and two focus signals from a light receiving/emitting element 100. The RF signal inputted to the RF signal exclusive input terminal 25 of an RF amplifier 112 is gainadjusted by an arithmetic operation amplifier 61, and outputted after its frequency characteristic is adjusted by an equalizer (EQ) circuit 62. Two focus signals PD1 and PD2 inputted from terminals 26 and 27 are respectively converted into voltages by current-voltage conversion amplifiers 79a and 79b, subjected to subtraction by an arithmetic operation amplifier 76 and then an obtained focus error signal FE is outputted. E and F signals inputted from terminals 23 and 24 are subjected to subtraction by an arithmetic operation amplifier 77 and then an obtained tracking error signal TE is outputted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk apparatus provided with an optical pickup which irradiates an optical disk with a light beam and obtains an RF signal and a servo error signal from the returned light.

[0002]

2. Description of the Related Art An optical disk apparatus for reproducing a signal recorded on an optical disk focuses a light beam on a signal surface of the optical disk, receives a return light thereof, and outputs a reproduced signal and a servo error signal. Optical pickup.

An optical disk mounted on a spindle of an optical disk drive and driven to rotate always has a track-direction deflection due to an eccentricity of a center hole or an eccentricity occurring at the time of chucking, and a deflection in an optical axis direction due to warpage or uneven thickness. Has occurred. For this reason, the optical pickup performs control so that the converged light beam always irradiates the track on the signal surface, following the deflection of the optical disk due to the rotation drive.

For example, a compact disc (CD) is
The track pitch is set to 1.6 μm, and the tracking control is performed so that the focal point of the light beam is in a range of about ± 0.1 μm from the track. Also,
The deflection width in the optical axis direction of the signal surface is allowed up to about ± 0.5 mm, while the focus point is ± 1 μm from the signal surface.
Focus control is performed so as to be in the range of about.

[0005] The control of the irradiation position of the light beam is as follows.
This is performed by, for example, finely moving a part of the optical system of the optical pickup with an actuator according to a control signal. This control signal is a tracking error signal or a focus error signal obtained from the return light from the optical disc,
The above control is performed by supplying these to the servo system.

A typical method for obtaining a tracking error signal is a three-beam method. In the three-beam method, a diffraction grating is arranged on the outward path of a light beam applied to an optical disk to generate three light beams consisting of a main beam (zero-order light) and two sub-beams (± first-order lights). This is a method of using two sub beams for tracking error detection. In this method, on both sides of the light receiving element for detecting the main beam,
A light receiving element for detecting two sub-beams is arranged, and a sub-beam generated according to a shift amount (a detrack amount) of a focus point of a main beam applied to a track of an optical disc from a track position. The tracking error signal is obtained from the change of the return light of the above.

As a typical method for obtaining a focus error signal, there is an astigmatism method. In the astigmatism method, an optical element for generating astigmatism such as a cylindrical lens is arranged on the return path of a light beam irradiated on an optical disc, and when the focal point of the light beam deviates from the signal plane in the optical axis direction. This is a method of obtaining a focus error signal by utilizing the fact that the shape of the incident spot changes from a circle to an ellipse according to the shift amount (defocus amount). In this method, a light receiving element having a light receiving surface divided into four is used, and when a light beam irradiated on an optical disk is converged on a signal surface, its shape is circular and minimized. Then, an unbalance in the amount of light incident on each of the four divided light receiving surfaces of the light receiving element, which is generated according to the defocus amount, is detected to obtain a focus error signal.

FIG. 8 shows a photodetector for outputting an RF signal, a signal for obtaining a focus error signal and a tracking error signal using the above-mentioned astigmatism method and the three-beam method, and a signal from the photodetector. 1 shows a basic configuration of a conventional optical pickup including an RF amplifier that amplifies, calculates, and outputs the result.

The photodetector 80 is a photodiode that outputs a signal current in accordance with the amount of incident light, and is divided into four light receiving surfaces A, B, C, and D to form a light receiving surface. , And six light receiving surfaces including a light receiving unit E and a light receiving unit F.

The light receiving section having the four divided light receiving surfaces is for receiving the return light of the main beam (0th order light) from the optical disk, and reproduces the light according to the signal recorded on the optical disk. A signal (RF signal) current is output.

In the amplifier 90, the signal A output from the light receiving surface A and the signal C output from the light receiving surface C arranged diagonally to each other are added by an adding means 81 to obtain a signal (A + C).
Is generated. Similarly, the signal B output from the light receiving surface B
The signal D output from the light receiving surface D is added by the adding means 82 to generate a signal (B + D). Then, the signal (A + C) and the signal (B + D) are added by the adding means 83, and the signal (A + B + C + D), which is the sum of the signals from the four divided light receiving surfaces, is output as an RF signal.

The light receiving section of the photodetector 80 having a light receiving surface divided into four parts, when the focal point of the light beam irradiated on the optical disk is shifted from the signal surface in the optical axis direction, the amount of the shift (defocus) It is also used to obtain a focus error signal by utilizing the fact that the shape of the incident spot changes from a circle to an ellipse due to astigmatism depending on the amount).

In the amplifier 90, the signal {(A + C)-(B + D)}, which is the difference between the signal (A + C) from the adding means 81 and the signal (B + D) from the adding means 82, is generated by the subtracting means 84. Is output as a focus error signal FE.

When the focal point of the light beam is on the signal surface of the optical disk (just focus), the light spot diameter on the light receiving surface is minimized and its shape is circular, so that each of the above four signals A ＤD become equal to each other, and the value of the focus error signal FE becomes 0.

However, when the signal surface of the optical disc and the objective lens are too close or too far apart from each other by a predetermined distance, the diameter of the light spot irradiated on the light receiving surface of the light receiving element increases, and For example, the shape becomes an ellipse long in the diagonal direction of the light receiving surface. In this case, since the above four signals are not balanced, the value of the signal {(A + C)-(B + D)} generated by the subtraction means 84 does not become 0, and the value corresponding to the defocus amount The focus error signal FE is output. Then, this focus error signal FE is supplied to the servo system and its value becomes 0.
The focus control is performed so that

On the other hand, a light receiving portion E and a light receiving portion F provided on both sides of a light receiving portion of the photodetector 80 having a four-divided light receiving surface.
Are used for tracking control by the three-beam method. One of the return lights of the two sub-beams (± 1st-order diffracted light) generated along with the main beam enters each of the light-receiving sections E and F.

When the main beam of light applied to the optical disk is converged on a track on the signal surface (on-track), of the returned light, the light amount of the sub-beam incident on the light receiving portion E and the light receiving portion F The light amounts of the incident sub-beams are equal to each other, and the signal E output from the light receiving unit E and the light receiving unit F
The value of the tracking error signal TE of the signal (E−F), which is the difference from the signal F output from, becomes zero.

However, if the main beam of light applied to the optical disc deviates from the track on the signal surface, the light quantity of the sub-beam incident on the light receiving section E and the light quantity of the sub-beam incident on the light receiving section F are not balanced. , The value of the signal (EF) does not become 0, and a tracking error signal TE having a value corresponding to the detrack amount is output. Then, the tracking error signal TE is supplied to the servo type, and the tracking control is performed so that the value becomes zero.

The photodetector 80 generally includes current-voltage conversion amplifiers 86a to 86d, 87 and 88 for converting a signal current output from each light receiving surface into a voltage and outputting the voltage. is there. As described above, by converting the signal current output from each light receiving surface of the light receiving element into a voltage, the arithmetic means for adding or subtracting each signal can be simply configured.

FIG. 9 shows a specific example of a conventional RF amplifier 90 which amplifies and calculates a signal from the above-described photodetector and outputs an RF signal, a focus error signal, and a tracking error signal. An example is shown.

That is, the signal (A + C) and the signal (B +
D) is added by the operational amplifier 83a to form an RF signal. Further, the signal (A + C) and the signal (B + D) are subtracted by the operational amplifier 84a to obtain a focus error (FE) signal. Further, the E signal and the F signal are
The tracking error (T) is subtracted by the operational amplifier 85a.
E) A signal.

FIG. 9 shows an adding means 81 for adding the signal A output from the light receiving surface A and the signal C output from the light receiving surface C to generate a signal (A + C), Although an adder 82 for adding the signal B output from B and the signal D output from the light receiving surface D to generate a signal (B + D) is not shown, these are provided on the photodetector 80 side. You may.

As described above, the conventional RF amplifier used in the optical pickup has a function of adding and subtracting two input signals, and outputs a reproduction signal and a focus error signal FE. . further,
It has a function of subtracting two other signals from the two input signals, and outputs a tracking error signal TE.

By the way, the above-mentioned optical pickup is
In order to make the device smaller and thinner, it has been proposed to use a light emitting and receiving element in which a light emitting element, a light receiving element section, and an optical element such as a prism are integrated on a substrate and integrally formed.

FIG. 10 shows a basic configuration of an optical pickup using the above-described light emitting / receiving element.

This optical pickup includes a light receiving element 10 and a light receiving / emitting element 100, and outputs an RF signal, a tracking error signal TE and a focus error signal FE.

The light receiving element 10 is a light receiving means for receiving return light of a light beam applied to the optical disk and outputting an RF signal. As the light receiving element 10, for example, a conventional photodetector used for a three-beam method as shown in this figure can be used, and the tracking error signal TE may be output together.

The light emitting / receiving element 100 has light receiving means for receiving return light from the optical disk and outputting a focus error signal. As described above, the light emitting / receiving element 100 is formed by integrating a light emitting element, a light receiving element portion, and an optical element such as a prism on a substrate, thereby forming a small and thin optical pickup. be able to.

[0029]

As described above, a conventional RF amplifier used in an optical pickup adds another two input signals to each other to obtain an R signal.
A function of outputting an F signal, a function of subtracting the two signals to output a focus error signal, and a function of subtracting two signals different from the two signals to output a tracking error signal. It is usually equipped.

On the other hand, as described above, in the optical pickup constructed by combining the conventional light receiving element and the light receiving / emitting element, the signal output from each light receiving section is different from the conventional one. For this reason, it cannot be directly connected to a conventionally used RF amplifier, and a new RF amplifier is required.

However, the conventionally used RF amplifier not only has a function as a preamplifier for amplifying a signal from a light receiving element and supplying it to a signal processing system, but also has various analog signal processing functions. It is typically supplied as an integrated circuit (IC) that also has

FIG. 11 shows an example of a main part of an existing RF amplifier having such a signal processing function.

The signal input to the terminal 26 and the signal input to the terminal 27 are subtracted by the operational amplifier 76 and output as a focus error signal FE. When focus control is performed by the astigmatism method using a light receiving element having a light receiving surface divided into four, a sum signal from light receiving surfaces positioned diagonally to each other is input to the terminals 26 and 27, respectively. .

The above signals input to the terminals 26 and 27 are added by the operational amplifier 75. The output of the operational amplifier 75 is gain-adjusted by the operational amplifier 61 via the capacitor C ₁ for AC coupling, and the equalizer (EQ)
After the appropriate frequency characteristic adjustment is performed by the circuit 62, the RF
Output as a signal. Capacitance C ₁ of the above, it may be external to the RF amplifier if necessary. The output of the operational amplifier 75 is also supplied to the servo system from the terminal 28 via a voltage control amplifier (VCA) 75b.

On the other hand, the signal input to the terminal 23 and the terminal 2
4 is subtracted by the operational amplifier 77 from the signal input to 4. A feedback resistor of the operational amplifier 77 is externally connected between the terminal 24 and the terminal 24a as necessary. The output of the operational amplifier 77 is output as the tracking error signal TE after the gain and frequency characteristics are adjusted by the voltage control amplifier (VCA) 77a and the operational amplifier 77b. When the tracking control is performed using the three-beam method, an E signal and an F signal corresponding to the amount of return light of the sub beam are input to the terminals 23 and 24, respectively.

As described above, the conventionally supplied RF
Since an RF signal is obtained by calculating two signals in an amplifier, the RF signal may be degraded. Further, since there are a plurality of paths for supplying a signal including an RF signal from the optical pickup to the RF amplifier, there is a problem that the signal is easily affected by noise.

The present invention has been made to solve such a problem, and has a small size and a small RF signal deterioration.
It is an object of the present invention to provide an optical disk device having a thin optical pickup.

[0038]

SUMMARY OF THE INVENTION An optical disk device according to the present invention proposed to solve the above-mentioned problem is directed to an optical disk device for reproducing a recorded signal by irradiating a focused optical beam to the optical disk. A first light receiving means for receiving a return light from the optical disk and outputting a reproduction signal corresponding to a signal recorded on the track; A second method for outputting first and second focus signals according to the amount of displacement
, A first processing means for calculating only the reproduction signal, and a second processing means for calculating the first and second focus signals.

According to the above configuration, it is possible to provide an optical disk apparatus having a small and thin optical pickup and having little deterioration of the RF signal.

[0040]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a preferred embodiment of an optical disk device according to the present invention will be described with reference to the drawings. In the following description, the same parts as those described above are denoted by the same reference numerals.

FIG. 1 shows a basic configuration of an optical pickup included in an optical disk apparatus according to the present invention, and an RF amplifier for amplifying, calculating, and outputting a signal from the optical pickup.

The optical pickup 111 includes a light receiving element 10 for outputting an RF signal, a first signal PD1 and a second signal P for generating a focus error (FE) signal.
A light emitting / receiving element 100 having a light receiving element for outputting D2 is provided. The E signal and the F signal for generating the tracking error (TE) signal may be output from either the light receiving element 10 or the light receiving / emitting element 100.

Each of the above signals output from the optical pickup 111 is normally transmitted through a flexible wiring or the like.
The signal is input to the F amplifier 112.

The RF amplifier 112 has an input terminal 25 dedicated to an RF signal. The input RF signal is gain-adjusted by an operational amplifier 61, and an appropriate frequency characteristic is adjusted by an equalizer (EQ) circuit 62. Output after being applied. The operation of the above-described equalizer circuit 62 is controlled to an appropriate characteristic by a control signal.

The signals PD1 and PD2 input from the terminals 26 and 27 are
After being converted into voltages at 9a and 79b, respectively, the voltage is subtracted at 76 by an operational amplifier to obtain a focus error (FE).
Output as a signal.

The E signal and the F signal input to the RF amplifier 112 from the terminals 23 and 24 are subtracted by the operational amplifier 77 and output as a TE signal.

FIG. 2 is a block diagram showing the configuration of an optical disk device according to the present invention, which is provided with the above-described optical pickup and RF amplifier.

In this optical disk apparatus, a signal recorded on an optical disk 110 rotated and driven by a spindle motor 119 is read by an optical pickup 111, subjected to necessary signal processing, and reproduced and output from a terminal 120.

The RF signal read from the optical disk 110 by the optical pickup 111 is first transmitted to the RF amplifier 1
In step 12, processing such as amplification is performed.
Signal processing. Then, the RF signal processed by the digital block 113 is converted from a digital signal to an analog signal by a D / A conversion circuit, amplified by an amplifier 115, and output from a terminal 120.

The digital block 113 is, for example, a DSP
(Digital Signal Processer) etc.
It performs data extraction by a digital PLL (Phase Locked Loop), EFM (Eight to Fourteen Modulation) demodulation and error correction.

The digital block 113 is connected to a memory 117 having a buffer function, and has a buffer management function, an interface function, and the like.

Servo block 116 (digital servo)
Is configured as a part of the digital block 113 described above. From the servo block 116, a position control signal for controlling the position of the optical pickup 111,
A rotation control signal for controlling the rotation of the spindle motor 119 is output.

The operations of the digital block 113 and the servo block 116 are performed by a CPU (Central Process
ng Unit).

Next, the configuration of the optical system of the optical pickup provided in the above-described optical disk device will be described.

FIG. 3 shows a specific example of the optical pickup 111.

The laser light emitted from the semiconductor laser (LD) 100a formed on the substrate 100c of the light emitting / receiving element 100 is reflected on the prism 1 provided on the substrate 100c.
00b is reflected by the slope on which the half mirror of 00b is formed, and travels toward the optical disk 110. This laser light is diffracted by a diffraction grating (grating) 11 to be converted into three beams consisting of a main beam (zero-order light) and two sub-beams (± first-order diffracted light). The light is condensed by the lens 13 and the signal surface 11 of the optical disc 110 is collected.
0a.

On the other hand, the return light from the optical disk 110 is
The beam splitter 12 separates an optical path toward the light receiving / emitting element 100 and an optical path toward the light receiving element 10.

In the light receiving element portion of the light receiving / emitting element 100, the return light incident on the prism 100b through the half mirror is converted into the prism 100 on which a mirror having a high reflectance is formed.
The light is reflected on the upper surface of the light receiving portion b and is incident on the light receiving portions 41 and 42 formed on the substrate 100c. In response to the return light, a signal DP1 and a signal DP for generating the focus error signal FE from the light receiving unit 41 and the light receiving unit 42.
2 is output.

According to such a configuration, the E signal component and the F signal component included in the return light of the light beam applied to the light disk 110 via the diffraction grating 11 are converted into the RF signal output from the light receiving element 10. , So that the RF signal does not deteriorate.

FIG. 4 schematically shows the light receiving surface of the light receiving element 10 used in the above optical pickup.

The light receiving element 10 has three light receiving surfaces for receiving three light beams in the three-beam method. More specifically, a light receiving unit 1 that receives a main beam and outputs only an RF signal, and receives a pair of sub beams symmetrically arranged on both sides of the light receiving unit 1 to output an E signal and an F signal. A light receiving section 2 and a light receiving section 3 are provided.

FIG. 5 shows the light emitting and receiving element 100 described above.
3 shows a more detailed configuration example.

This light emitting / receiving element 100 is
Light emitting element 100a that generates a light beam irradiated to zero
And two light receiving units 41 and 42 for receiving the light beam reflected from the optical disk 110, and a prism 100b for guiding the light beam emitted from the light emitting element 100a to the optical disk 110 and the light receiving unit 41 and the light receiving unit 42. It is formed integrally on the substrate 100c. Such a light receiving and emitting element is one in which each optical element is integrated using semiconductor technology, a semiconductor laser (LD) is used as the light emitting element, and a photodiode (PD) is used as the light receiving element. Is used.

Light beam 1 emitted from light emitting element 100a
Reference numeral 8 denotes an inclined surface 105 of the prism 100b on which a semi-transmissive film (half mirror) is formed, and a part of the reflected light is incident on the objective lens 13. The objective lens 13 focuses this light beam on the signal surface 110a of the optical disc 110.
The light beam focused on the signal surface 110a is
The slope 1 is reflected by 10a and again through the objective lens 13.
05, and a part of the light is transmitted to the light receiving unit 41 through the slope 105.

Since a half mirror is formed on the surface of the light receiving section 41, a part of the irradiated light passes through the half mirror and is incident on the light receiving section 41. Outputs the corresponding signal. The light reflected by the half mirror on the surface of the light receiving unit 41 is further reflected by the reflecting surface 106 formed on the upper surface of the prism 100b and is incident on the light receiving unit 42. The light receiving unit 42 outputs a signal corresponding to the amount of incident light. Is output. The light receiving section 41 and the light receiving section 42
Is an optical element 110 for returning light from the optical disc.
Are located before and after the conjugate point for. In addition,
The above conjugate point is also a conjugate point with respect to the converging point of the light irradiated on the optical disc 110. And this light receiving section 41
And the signal PD2 from the light receiving unit 42 are used for focus control.

FIG. 6 shows the structure of the light receiving element of the light receiving and emitting element 100 described above.

The light receiving element portion of the light receiving / emitting element 100 used in this optical pickup includes a light receiving section 41 and a light receiving section 42 each having a light receiving surface divided into three.

A light receiving surface A, which is a pair of second light receiving surfaces, and a light receiving surface A, which is a pair of second light receiving surfaces, are provided on both sides of a light receiving surface B, which is a first light receiving surface, provided at the center among the three light receiving surfaces of the light receiving portion 41. The light receiving surface C, which is the light receiving surface of No. 3, is arranged symmetrically. Similarly, on both sides of a light receiving surface B ′ as a first light receiving surface provided at the center of the three light receiving surfaces of the light receiving portion 42, a light receiving surface A ′ as a pair of second light receiving surfaces is provided. And the light receiving surface C ′ as the third light receiving surface are symmetrically arranged.

The signal B output from the light receiving surface B of the light receiving unit 41 and the signal A ′ output from the light receiving surface A ′ of the light receiving unit 42
The signal C ′ output from the light receiving surface C ′ is added by the operational amplifier 56 and output as a signal PD1.
Similarly, a signal B ′ output from the light receiving surface B ′ of the light receiving unit 42, a signal A ′ output from the light receiving surface A ′ of the light receiving unit 41, and a signal C ′ output from the light receiving surface C ′ ,
The signals are added by the operational amplifier 57 and output as a signal PD2.

Although FIG. 6 does not show a current-voltage conversion amplifier for converting a signal current output from each light receiving surface in accordance with the amount of incident light into a voltage, the number of currents equal to the number of light receiving surfaces is omitted. Usually, a voltage conversion amplifier is provided.
The signals output from the respective light receiving surfaces are converted into voltages and then subjected to arithmetic processing such as addition.

FIG. 7 shows a connection example in which the number of current-voltage conversion amplifiers is reduced in the above-mentioned light receiving and emitting element.

More specifically, the light receiving surfaces A and C at both ends of the light receiving portion 41 are connected to the central light receiving surface B ′ of the light receiving portion 42, and the signal PD is output via the current / voltage conversion amplifier 45.
1 is output. Similarly, the light receiving surfaces A ′ and C ′ at both ends of the light receiving unit 42 are connected to the light receiving surface B at the center of the light receiving unit 41, and the current-voltage conversion amplifier 46
To output the signal PD2 via the.

The current-voltage conversion amplifiers 45 and 46 may be omitted to output a signal current. Further, a calculation means for generating a signal (PD1-PD2) which is a difference between the signal PD1 and the signal PD2 may be further provided to generate and output the focus error signal FE.

Next, the operation of generating a focus signal in the light emitting / receiving element 100 of the optical pickup will be described.

When the main beam irradiated on the optical disk 110 is focused on the track on the signal surface 110a (just focus), the spot diameters of the return lights entering the two light receiving portions 41 and 42 are equal to each other. It is to be. That is, the signal B and the signal (A ′ +
C ′) and the sum of the signal B ′ and the signal (A + C) are made equal to each other.

Therefore, at the time of just focus, the first
Signal PD1 and the second signal PD2
Are equal to each other, and the value of the generated focus error signal FE becomes 0.

On the other hand, in the above configuration, the optical disc 1
When the distance between the signal surface 110a of the reference numeral 10 and the objective lens 13 is too short or too far from a predetermined distance, the spot of the return light incident on the two light receiving sections 41 and 42 described above. The diameters are not equal to each other, and the value of the generated focus error signal FE does not become zero.

The value of the focus error signal FE is a deviation from the above-mentioned predetermined distance, that is, a defocus amount which is a deviation amount of the converging point of the light beam irradiated on the optical disk from the signal surface in the optical axis direction. It becomes a value according to.

For example, the objective lens 13 and the optical disk 11
0 is too far away, the value of signal PD1 is positive,
The value of the signal PD2 becomes negative, and the signal (P
The value of D2-PD1) becomes negative. This is optical disk 1
Since the opening angle of the return light from the optical disk 110 becomes smaller than the opening angle of the light beam toward the optical disk 110, the return light incident on the prism 100b is focused before being reflected on the upper surface of the prism 100b. , Light receiving section 41
This is because the upper spot diameter becomes smaller than the spot diameter on the light receiving section 42.

On the contrary, if the objective lens 13 and the optical disk 110 are too close, the signal P
The value of D1 is negative, the value of signal PD2 is positive, and the value of the difference (PD2-PD1) is positive. This is because the opening angle of the return light from the optical disk 110 is larger than the opening angle of the light beam toward the optical disk 110, so that the return light incident on the prism 100b is focused after being reflected by the upper surface of the prism 100b. That is, the spot diameter on the light receiving unit 41 is larger than the spot diameter on the light receiving unit 42.

[0081]

As described above, according to the present invention,
Since the RF amplifier is provided with an input terminal dedicated to RF signals, an RF pickup from a small and thin optical pickup using a light receiving / emitting element in which a light emitting element, a light receiving element, and an optical element such as a prism are integrated. An optical disk device with less signal degradation can be provided.

[Brief description of the drawings]

FIG. 1 is a diagram showing a basic configuration of an optical pickup and an RF amplifier included in an optical disk device according to the present invention.

FIG. 2 is a block diagram illustrating a configuration of an optical disc device according to the present invention.

FIG. 3 is a diagram showing a specific example of an optical pickup included in the optical disc device according to the present invention.

FIG. 4 is a diagram for explaining a light receiving element for outputting an RF signal of the optical pickup according to the present invention.

FIG. 5 is a diagram showing an optical system of a light receiving / emitting element for outputting a focus error signal of the optical pickup according to the present invention.

FIG. 6 is a diagram illustrating a configuration example of a light receiving element unit of the light receiving and emitting element.

FIG. 7 is a diagram showing another configuration example of the light receiving element portion of the light receiving and emitting element.

FIG. 8 is a diagram showing a basic configuration of a conventional optical pickup.

FIG. 9 is a diagram for explaining a configuration of a conventional RF amplifier.

FIG. 10 is a diagram illustrating a basic configuration of an optical pickup using a light receiving / emitting element.

FIG. 11 is a diagram illustrating an example of a main part of an RF amplifier also having a signal processing function.

[Explanation of symbols]

10 light receiving elements, 23, 24, 26, 27 terminals,
25 RF signal input terminal, 61, 76, 77 operational amplifier, 100 light receiving / emitting element, 111 optical pickup, 112 RF amplifier

Claims (4)

[Claims] An optical disk apparatus for reproducing a recorded signal by irradiating a focused optical beam to an optical disk and receiving a return light from the optical disk and responding to a signal recorded on a track. A first light receiving means for outputting a reproduction signal, and a second light receiving means for outputting first and second focus signals corresponding to a shift amount between a focal point of a light beam irradiated on the optical disc and a signal surface. An optical disc device comprising: first processing means for calculating only the reproduction signal; and second processing means for calculating the first and second focus signals. 2. The first light receiving means receives a return light generated according to a signal recorded on a track of the optical disk, and outputs only a reproduction signal,
Receiving return light generated in accordance with the amount of deviation of the focal point of the light beam applied to the optical disk from the track position and symmetrically disposed with the first light receiving portion interposed therebetween, and responding to the amount of deviation. 2. The optical disk device according to claim 1, further comprising second and third light receiving units for outputting the respective signals. 3. The second light receiving means has a first light receiving portion and second and third light receiving portions symmetrically arranged with the first light receiving portion interposed therebetween. A first light receiving unit disposed before the point, a first light receiving unit, and second and third light receiving units disposed symmetrically with respect to the first light receiving unit; And a second light receiving means disposed before the conjugate point of the second light receiving means. The first light receiving part of the first light receiving means and the second and third light receiving parts of the second light receiving means A first focus signal corresponding to a shift amount of a light beam irradiated on the optical disk from a signal surface in an optical axis direction is output, and a first light receiving unit of the second light receiving unit and a first light receiving unit of the first light receiving unit are output. The light beam irradiating the optical disk from the second and third light receiving units is shifted in accordance with the amount of deviation from the signal surface in the optical axis direction. 2. The optical disk device according to claim 1, wherein the optical disk device outputs a second focus signal. 4. A diffraction grating for diffracting a light beam applied to the optical disk to generate two sub-beams, and an optical path for returning light from the optical disk, the first light receiving means and the second light receiving means. 2. The optical disk device according to claim 1, further comprising a separating unit that separates the optical disk from the optical disk.