JPH11259965A - Device and method for discriminating optical record medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately and speedily discriminate many kinds of disks by simultaneously lighting a first and a second light beams, simultaneously moving the corresponding objective lenses and discriminating the kind of an information record medium from the focus error signals generated at the focal positions of these beams. SOLUTION: The inter-peak distance of the sigmoid curve is read by a LD3e for CD generated at a focal point and stored in a memory 10. Then, the peak to peak distance of the sigmoid curve is read by a LD3d for DVD and stored in the memory 10. The obtained FEcd value is read from the memory 10, compared against a reference value and it is discriminated as a CD if the FEcd is equal to 1.0 Vp-p or more. If the FEcd is less than 1.0 Vp-p, the obtained FEdvd value is read from the memory 10, compared against the reference value and it is discriminated to be a DVD if an FEdvd is equal to 1.0 Vp-p or more. If the FEdvd value is less than 1.0 Vp-p, it is discriminated to be a CD-RW.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention
The present invention relates to an optical recording medium discriminating apparatus and method for discriminating a plurality of types of optical recording media having different thicknesses and reflectivities such as D, CD-R, and CD-RW.

[0002]

2. Description of the Related Art In recent years, as optical disks, in addition to CDs (compact disks), DVDs (digital video disks) and Cs, which have a much larger storage capacity than CDs, have been used.
DR (writable only once), CD-RW (writable a predetermined number of times), and the like have been developed.

An optical recording medium having different thicknesses and different reflectivities is irradiated with a light beam as information reproducing light,
The following recording / reproducing apparatus reproduces information recorded on an optical recording medium by the reflected light.

FIG. 11 is a block diagram showing a configuration of a conventional recording / reproducing apparatus.

In this recording / reproducing apparatus, a signal from, for example, a compact disc (hereinafter, referred to as a CD) set is read by a pickup 103 for reproducing a CD and input to a preamplifier 105. Further, a disc 104 having a thickness different from that of a CD, for example, a DVD playback pickup 104 is also provided. When a DVD is set, the output of the pickup 104 is similarly input to the preamplifier 105.

The preamplifier 105 includes a pickup 103
Alternatively, an RF signal, a tracking error signal (TE), and a focus error signal (FE) are generated by the output of 104.

Further, APC circuits 123 and 124 are provided for controlling the power of the laser light emitted in the pickups 103 and 104, respectively, and these are controlled by the CPU 121. The CPU 121 also controls on / off of the laser light.

[0008] The FE signal generated by the preamplifier 105 is input to the servo amplifier 106, and the A / D converter 106a
After being converted to an analog signal by a D / A converter 106c via a circuit 106b of an equalizer (EQ) and an amplifier (Amp), the signal is input to a driver circuit 107 for driving a focus coil. And CD / DVD
Switch 110 is set to CPU 1
21 to switch the pickup 103 or 1
Drive the focus coil in 04.

The TE generated by the preamplifier 105
The signal is input to the A / D converter 106d, and is passed through a circuit 106e including an equalizer (EQ) and an amplifier (Amp).
After being converted into an analog signal by the D / A converter 106f, the signal is input to the driver circuit 108 for driving the tracking coil. The switch 109 is switched by the CPU 121 to drive the tracking coil in the pickup 103 or 104 depending on which of CD and DVD is reproduced.

Note that the A / D converters 106a and 106d
Is connected so that data can be read from the CPU 121,
The CPU stores the read data in the memory 122.

On the other hand, the RF generated by the preamplifier 105
The signal is input to the decoder 125 and the A / D converter 125
a, the equalizer (EQ) and amplifier (Amp) circuit 125b and the synchronization detection circuit 12
5e, a spindle (SPDL) error circuit 12
5j. In the SPDL error circuit 125j,
After an error is generated and converted into an analog signal by the D / A converter 125k, the spindle motor 102 is driven by the driver circuit 127.

Further, an equalizer (EQ) and an amplifier (A
mp) to generate a track count signal based on the RF signal via the circuit 125b.
c and the Bottom detector 125d to generate top and bottom envelope signals, respectively.

The top and bottom envelope signals are added by an adder 125f to generate a signal having an amplitude due to a track cross formed from the upper and lower envelopes of the RF signal. This signal is sliced at a fixed slice level, and the track count circuit 125g counts tracks at the time of search. Based on the result, a carriage error is generated by the carriage error circuit 125h, and further converted into an analog signal by the D / A converter 125i, and then input to the driver circuit 126. Driver circuit 1
The CARG signal output from the switch 26 is switched by the switch 111 depending on which of CD and DVD is reproduced, and drives the carriage motor 103A or 104A.

In the recording / reproducing apparatus having such a configuration, when reproducing a CD and a DVD as disks having different thicknesses, the CD is normally irradiated with a laser having a wavelength of 780 nm, and the DVD is reproduced by a laser having a wavelength of 650 nm. Before the reproduction, it is necessary to determine which type of disc is set.

As a method of discriminating the type of the disc, for example, the CD laser is first turned on, then the focus actuator is turned up / down, and the level of the focus error signal FE obtained at the focused point is compared with a reference value. In some cases, discrimination between CD and DVD is performed (first
Conventional example).

A specific description will be given with reference to FIG. After the disc 101 is set in the recording / reproducing apparatus, first, for example, the laser in the CD pickup 103 is emitted. Next, the focus actuator in the pickup 103 is lowered to the bottom and raised (T11 in FIG. 12). At this time, since an S-shaped curve appears in the focus error signal FE near the focus, the level of this error signal is read by the CPU 121 and stored in the memory 122.

The CPU 121 reads the stored S
The character curve level is compared with a reference value set in advance in the CPU internal ROM to determine whether it is a CD or DVD. For example, if the disc 101 is a CD, C
When the laser of the D pickup 103 is irradiated with the laser, the S-shaped level becomes 1.3 Vp-p (T13).
01 is a DVD, a CD pickup 103
In such a case, the error signal FE cannot obtain a sufficient level because the beam cannot be sufficiently stopped, and the like.
−p (T12).

As shown in FIG. 12, the reason why the S-shaped curve of the DVD appears before the S-shaped curve of the CD is that the thickness up to the reflection surface of the disc is different and the DVD is thinner, that is, closer. It is. For this reason, for example, 1.0 Vp-p
If so, it is determined to be a CD. If it is determined that the switch is a CD, the control signal from the CPU 121 becomes, for example, “H” level, and the switches 109, 110, 111
Remain connected to the CD pickup 103 side.

However, in the case of an apparatus that reproduces not only CDs and DVDs but also CD-RWs, the S-curve level of the CD-RWs at the CD pickup 103 is only 0.3 Vp-p. It is determined to be a DVD. Therefore, when it is determined that the set disc is not a CD, the disc is DVD or CD-RW.
Since it is not yet known, the mode is switched to the DVD pickup 104, and the disk 101 is irradiated with the DVD laser (T14 in FIG. 12). When the DVD laser is applied to the DVD, for example, an S-curve level of 1.3 Vp-p is obtained, and an S-curve level of CD-RW is 0.9 pp (T15). As a result, if the determination level is set to 1.0 Vp-p, DVD and CD
-RW can be determined.

As a technique for quickly and accurately discriminating various kinds of optical disks, there is one disclosed in Japanese Patent Application Laid-Open No. 9-265722 (second conventional example).

This technique uses an effective numerical aperture N of an objective lens.
A detects / determines the peak value or the number of peaks of the S-shaped curve of the focus error signal detected in the process of performing the focus servo using an optical pickup suitable for recording / reproducing on an optical disk having a thin substrate. FIG. 13 shows the structure of a pickup used in this publication.

In FIG. 13, a light beam emitted from a semiconductor laser 201 passes through a diffraction grating 202, a collimating lens 203, a polarizing beam splitter 204, and a quarter-wave plate 205 sequentially, and further passes through an aperture 206. Is focused by the objective lens 207 and
It is irradiated to 0.

The light beam reflected by the optical disk 300 passes through the objective lens 207, the aperture 206, and the quarter-wave plate 205 sequentially, and returns to the polarization beam splitter 204. This polarization beam splitter 204
After being reflected in the direction perpendicular to the direction of the incident beam, the light passes through the condenser lens group 208 and is detected by the photodetector 209.

The aperture 206 of this optical pickup
Has a structure in which the effective numerical aperture NA can be changed in order to enable compatible reproduction of a CD and a DVD (one layer, two layers). This is because the distance from the substrate surface to the signal recording surface is different between CD and DVD, and it is not possible to focus them with a single objective lens. Therefore, the effective numerical aperture NA is set according to the distance to the signal recording surface. By changing
It is designed to be able to focus on signal recording surfaces at two different distances.

In the state where the effective numerical aperture NA is set to 0.6, the focus search is started after the optical disk is mounted, and the optical detector 209 of the optical pickup shown in FIG. 14A or FIG. When an S-shaped curve as shown in the figure is detected, a DVD (one layer) has a larger peak value of the detected S-shaped curve, and a CD has a smaller peak value.
Is determined. FIG. 14B or FIG.
When an S-shaped curve as shown in (c) is detected,
The number of detected S-shaped curves can be determined. If the number of S-shaped curves is two, the disc is determined as DVD (two layers).

[0026]

However, in the first and second conventional examples which are the conventional disk discriminating methods,
There were the following problems.

(1) In the first conventional example, if the disc to be discriminated is of two types, CD and DVD, discrimination can be made quickly and accurately, but the object to be reproduced is C
D, CD-R, CD-RW, DVD (single layer), DVD
As the number of types increased (e.g., two layers), it was not possible to discriminate all disks by simply irradiating a laser for CD and performing one up / down operation. Therefore, DVD
Up / down by irradiating laser for CD, or laser for CD → DVD laser → CD laser → DVD
In some cases, the disc is discriminated by irradiating / turning off the laser many times like a laser. In this method, depending on the disc, it takes a very long time until the disc is finally discriminated, and the laser is frequently irradiated / turned off, so that the life of the laser may be shortened.

(2) In the disk discriminating method disclosed in the above publication,
By using a semiconductor laser of one wavelength and raising / lowering the objective lens in a state where the effective numerical aperture NA of the objective lens is 0.6, a CD, a DVD (single layer) and a DVD (two layers) are discriminated. CD-R as a disc type to be discriminated,
When the CD-RW is added, the levels of the S-shaped curves are close to each other, so that there is a problem that the discrimination method cannot accurately discriminate.

The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to provide an optical recording medium discriminating apparatus capable of discriminating various kinds of discs accurately and quickly. And a method.

[0030]

Means for Solving the Problems To achieve the above object, a first aspect of the present invention is directed to an information recording surface of the first information recording medium for reproducing recorded information from the first information recording medium. First light beam lighting means for lighting a first light beam applied to the first light beam, a first objective lens for forming a focal point of the light beam on the optical axis of the first light beam, Second light beam lighting means for lighting a second light beam applied to an information recording surface of the second information recording medium for reproducing recorded information from the second information recording medium; and the second light beam. A second objective lens for forming a focal point of the light beam on the optical axis of the beam; and a first objective lens, a second objective lens, and an information recording surface of the first or second information recording medium. In order to change the relative distance parallel to the optical axis, the first and second
Lens moving means for moving the objective lens, and receiving the reflected light from the information recording surface by the first and second light beams in accordance with the change of the relative distance, and receiving the first and second light, respectively. First and second light receiving means for outputting a signal,
A focus error signal generating unit for generating a focus error signal corresponding to the first and second light receiving signals based on the first and second light receiving signals; and a focus error signal generating unit corresponding to the first and second light receiving signals. A pickup including an RF signal generating unit for generating an RF signal, the first and second light beam lighting units, the first and second objective lenses, the lens moving unit, and the first and second light receiving units. A pickup moving means for moving the first and second light beams simultaneously to the inner and outer peripheries of the information recording surface, wherein the first and second light beams are simultaneously turned on and the first and second light beams are turned on. Control means for simultaneously moving the two objective lenses, storage means for storing focus error signals respectively generated at the in-focus positions of the first and second light beams, and In that a discrimination means from 憶 focus error signal to determine the type of the first and second information recording medium.

A feature of the second invention is that a first light beam for illuminating a first light beam applied to an information recording surface of the first information recording medium to reproduce recorded information from the first information recording medium is provided.
A light beam lighting means, a first objective lens for forming a focal point of the light beam on an optical axis of the first light beam, and a light source for reproducing recorded information from a second information recording medium. Second light beam lighting means for lighting a second light beam applied to the information recording surface of the second information recording medium; and forming a focal point of the light beam on the optical axis of the second light beam. And a first objective lens for changing a relative distance parallel to the optical axis between the first objective lens and an information recording surface of the first or second information recording medium. First lens moving means for moving a lens;
Second lens moving means for moving the second objective lens to change a relative distance between the objective lens and the information recording surface of the first or second information recording medium parallel to the optical axis; With the change of the relative distance by the first and second lens moving means, light reflected from the information recording surface by the first and second light beams is received, and the first and second light receptions are performed. First and second light receiving means for outputting a signal, and a focus error signal generating means for generating a focus error signal corresponding to the first and second light receiving signals based on the first and second light receiving signals And R for generating RF signals corresponding to the first and second light receiving signals.
F signal generating means, the first and second light beam lighting means, the first and second objective lenses, the first and second light beams
An optical recording medium discriminating apparatus comprising: a lens moving unit; and a pickup moving unit that moves a pickup having the first and second light receiving units to the inner and outer peripheries of the information recording surface. And control means for controlling the first and second light beams simultaneously by controlling the first and second light beams by controlling the first and second light beams, and the first and second light beams. Storage means for storing a focus error signal generated at each in-focus position of the light beam, and determination means for determining the types of the first and second information recording media from the focus error signal stored in the storage means. Have prepared.

A feature of the third invention is that a first light beam for illuminating a first light beam applied to an information recording surface of the first information recording medium to reproduce recorded information from the first information recording medium is provided.
A light beam lighting means, a first objective lens for forming a focal point of the light beam on an optical axis of the first light beam, and a light source for reproducing recorded information from a second information recording medium. Second light beam lighting means for lighting a second light beam applied to the information recording surface of the second information recording medium; and forming a focal point of the light beam on the optical axis of the second light beam. And a first objective lens for changing a relative distance parallel to the optical axis between the first objective lens and an information recording surface of the first or second information recording medium. First lens moving means for moving a lens;
Second lens moving means for moving the second objective lens to change a relative distance between the objective lens and the information recording surface of the first or second information recording medium parallel to the optical axis; With the change of the relative distance by the first and second lens moving means, light reflected from the information recording surface by the first and second light beams is received, and the first and second light receptions are performed. First and second light receiving means for outputting a signal, and a focus error signal generating means for generating a focus error signal corresponding to the first and second light receiving signals based on the first and second light receiving signals And R for generating RF signals corresponding to the first and second light receiving signals.
F signal generating means, the first and second light beam lighting means, the first and second objective lenses, the first and second light beams
An optical recording medium discriminating apparatus comprising: a lens moving unit; and a pickup moving unit that moves a pickup having the first and second light receiving units to the inner and outer peripheries of the information recording surface. And the first objective lens is moved, and then the first objective lens is moved.
Control means for turning on the second light beam and moving the second objective lens before turning off the light beam of
Storage means for storing focus error signals respectively generated at the in-focus positions of the first and second light beams; and determining the types of the first and second information recording media from the focus error signals stored in the storage means. Determining means for determining.

A fourth aspect of the present invention is characterized in that first light beam lighting means for lighting a first light beam for reproducing recorded information from a first information recording medium, and a light beam of the first light beam. A first objective lens for forming a focal point of the light beam on the axis, and a second light beam lighting means for lighting a second light beam for reproducing recorded information from a second information recording medium; A second objective lens for forming a focal point of the light beam on the optical axis of the second light beam; an information recording surface of the first objective lens and the first or second information recording medium; A first lens moving means for moving the first objective lens to change a relative distance parallel to the optical axis with the first objective lens and the second objective lens and the first or second information recording medium. Before changing the relative distance parallel to the optical axis with the information recording surface, A second lens moving means for moving a second objective lens, and a change in the relative distance by the first and second lens moving means, from the information recording surface by the first and second light beams. First and second light receiving means for receiving the reflected light of the first and second and receiving the first and second light receiving signals, respectively, based on the first and second light receiving signals, Focus error signal generating means for generating a focus error signal corresponding to a light receiving signal; RF signal generating means for generating an RF signal corresponding to the first and second light receiving signals; and the first and second light beams Lighting means, the first and second objective lenses, the first and second lens moving means, and the first and second objective lenses;
An optical recording medium discriminating device comprising: a pickup moving means for moving a pickup having light receiving means to the inner and outer peripheries of the information recording surface, wherein the first and second light beams are turned on simultaneously or separately. Control means for moving the second objective lens at a speed different from the moving speed of the first objective lens after or simultaneously with moving the first objective lens, and the first and second lights Storage means for storing a focus error signal generated at each focus position of the beam; and determination means for determining the type of the first and second information recording media from the focus error signal stored in the storage means. It is in.

A fifth aspect of the present invention is characterized in that a first light beam for illuminating a first light beam applied to an information recording surface of the first information recording medium in order to reproduce recorded information from the first information recording medium.
Light beam lighting means, and a second light beam lighting means for lighting a second light beam applied to an information recording surface of the second information recording medium in order to reproduce recorded information from the second information recording medium. Means, an objective lens for forming a focal point of the light beam on the optical axis of the first and second light beams, the objective lens and an information recording surface of the first or second information recording medium. Lens moving means for moving the objective lens in order to change the relative distance parallel to the optical axis; and, from the information recording surface by the first and second light beams with the change in the relative distance. Light separating means for separating reflected light, and first and second light receiving means for outputting first and second light receiving signals corresponding to the respective reflected lights received through the light separating means.
A focus error signal generating means for generating a focus error signal corresponding to the first and second light receiving signals based on the first and second light receiving signals; and the first and second light receiving means. A pickup having an RF signal generating means for generating an RF signal corresponding to the light receiving signal, the first and second light beam lighting means, the objective lens, the lens moving means, and the first and second light receiving means; An optical recording medium discriminating device comprising: a pickup moving means for moving the objective lens to the inner and outer peripheries of the information recording surface, wherein the first and second light beams are simultaneously turned on and the objective lens is simultaneously moved. Control means for causing
Storage means for storing focus error signals respectively generated at the in-focus positions of the first and second light beams; and determining the types of the first and second information recording media from the focus error signals stored in the storage means. Determining means for determining.

According to a sixth aspect of the present invention, in the first to fifth aspects, the storage means stores an S-shaped curve in a focus error signal generated at a focus position of each of the first and second light beams. And the discrimination means compares the signal level stored in the storage means with a reference value to determine the type of the first and second information recording media. I did it.

According to a seventh aspect of the present invention, in the first to fifth aspects, the storage means stores an S-shaped curve in a focus error signal generated at a focus position of each of the first and second light beams. The peak-to-peak level and the shape of each of the S-shaped curves are stored, and the determination means compares the signal level stored in the storage means with a reference value, and determines the shape of each of the S-shaped curves. And that the types of the first and second information recording media are determined based on the comparison results.

According to an eighth aspect of the present invention, in the first to fifth aspects, the storage means stores an S-shaped curve in a focus error signal generated at a focus position of each of the first and second light beams. And the discriminating means stores the peak-to-peak level of each S stored in the storage means.
The type of the first and second information recording media is determined from the signal level of the character curve.

A ninth aspect of the present invention is characterized in that a first light beam for irradiating an information recording surface of the first information recording medium with light to reproduce recorded information from the first information recording medium is turned on.
A light beam lighting means, a first objective lens for forming a focal point of the light beam on an optical axis of the first light beam, and a light source for reproducing recorded information from a second information recording medium. Second light beam lighting means for lighting a second light beam applied to the information recording surface of the second information recording medium; and forming a focal point of the light beam on the optical axis of the second light beam. A second objective lens for lighting the first and second light beams simultaneously to record information on the first and second objective lenses and the first or second information recording medium. The first and second objective lenses are simultaneously moved to change a relative distance parallel to the optical axis with respect to a plane, and the information recording is performed by the first and second light beams with the change in the relative distance. Receiving the reflected light from the surface and outputting the first and second light receiving signals, respectively. Then, a focus error signal corresponding to the first and second light receiving signals is generated based on the first and second light receiving signals, and generated at the in-focus positions of the first and second light beams, respectively. And storing the focus error signal in the storage means, and determining the types of the first and second information recording media from the focus error signal stored in the storage means.

[0039]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an optical recording medium discriminating apparatus according to the present invention will be described below.

(First Embodiment) FIG. 1 is a block diagram showing a configuration of a recording / reproducing apparatus equipped with an optical recording medium discriminating apparatus according to a first embodiment of the present invention.

In the vicinity of the disk 1 set in this recording / reproducing apparatus, a spindle motor 2 for rotating the disk 1 and a pickup (PU) 3 for irradiating a light beam to read information recorded on the disk 1 And are arranged. The pickup 3 has an optically two-system structure corresponding to the type of the disc as shown in FIG.
The drive of the carriage motor 4 moves the inner and outer circumferences of the disk 1.

A preamplifier 5 is connected to the output side of the pickup 3. The preamplifier 5 includes an RF signal and a tracking error signal T as in the conventional device (FIG. 11).
E is a circuit configuration that generates two focus error signals FE corresponding to the two systems of the pickup 3 in addition to generating E. That is, the focus error signal FE
As a result, the FE (1) signal from the light emitting element (LD) for CD and the FE (2) signal from the LD for DVD are output.

The output side of the preamplifier 5 is connected to a servo amplifier 6. The servo amplifiers 6 correspond to the focus error signal FE and the tracking error signal TE in the same manner as in the above-described conventional device, and correspond to the A / D converters 6a, 6a.
d, and circuit units 6b and 6e comprising an equalizer and an amplifier.
And D / A converters 6c and 6f. However, unlike the conventional device, the A / D converter 6a is configured to take in the above-mentioned FE (1) signal and FE (2) signal generated at the same time in a time-sharing manner and binarize it. FO is provided on the output side of the D / A converters 6c and 6f of the servo amplifier 6.
The driver 7 that outputs the CS signal and the driver 8 that outputs the TRKG signal are connected to each other, and the output FO
The CS signal and the TRKG signal are fed back to the pickup 3.

On the other hand, the CPU 9 stores the conversion results of the A / D converters 6a and 6d in the memory 10 and controls the APC circuits 11 and 12, as in the conventional device. Flow chart shown in FIG. 4 (described later)
Disc discrimination control according to the above.

The RF signal output from the preamplifier 5 is input to the decoder 13. The decoder 13 includes an A / D converter 13a, a circuit 13b including an equalizer and an amplifier, a Top detector 13c, and a Bo, as in the conventional device.
ttom detector 13d, synchronization detection circuit 13e, adder 1
3f, track count 13g, carriage error 13
h, D / A converter 13i, SPDL error circuit 13j,
And a D / A converter 13k.

The output of the D / A converter 13i drives the carriage motor 4 of the pickup 3 as a CARG signal via the driver 14, and the D / A converter 1
The 3k output SPDL drives the spindle motor 2 via the driver 15.

FIG. 2 is a diagram showing the structure of the pickup 3 shown in FIG.

For example, when the disk to be reproduced is a CD, CD-RW or DVD,
An objective lens 3a for DVD, an objective lens 3b for DVD,
Object lens 3a for CD and object lens 3b for DVD
Coil 3c, DVD semiconductor laser (LD) 3d, CD semiconductor laser (LD) 3e, CD half mirror 3h and mirror 3i, DVD half mirror 3f and mirror 3g.

For example, a laser beam emitted from a semiconductor laser 3e for CD passes through a half mirror 3h, is reflected in a right angle direction by a mirror 3i, is condensed by an objective lens 3a, and is irradiated on the disk 1. You. And disk 1
The laser light reflected by the light source passes through the objective lens 3a in a direction opposite to that of the incident light, and is reflected by the mirror 3i and the half mirror 3h in directions perpendicular to each other, and then enters the light receiving element 3k.

Similarly, the laser light emitted from the DVD semiconductor laser 3d passes through the half mirror 3f, is reflected by the mirror 3g in a right angle direction, and then is reflected by the objective lens 3b.
And irradiates the disk 1. Then, the laser beam reflected by the disk 1 passes through the objective lens 3b in a direction opposite to the direction of the incident light, and the mirror 3g and the half mirror 3f
After being reflected in the directions perpendicular to each other, the light enters the light receiving element 3i.

As described above, the pickup 3 has an optically two-system structure corresponding to the type of the disc. The semiconductor lasers 3e and 3d are connected to the output sides of the APC circuits 11 and 12, respectively, and the light-receiving elements 3k and 3k are connected. 3 j is connected to the input side of the preamplifier 5.

Next, the operation of the present embodiment configured as described above will be described.

FIG. 3 is a diagram showing waveforms at various points in the present embodiment.

First, the focus coil 3c is lowered, and C
The LD 3e for D and the LD 3d for DVD emit light (T 3 in FIG. 3).
1) The disk is raised toward the disk 1. When the set disc is a DVD, the S-shaped curve (FE2) of the focus error signal FE (1) by the CD LD 3e is used.
= 0.6 Vp-p) and the S-shaped curve of the focus error signal FE (2) by the LD 3d for DVD (FE5 = 1.
3Vpp) (T2).

When the set disc is a CD, the reflection surface is farther than the DVD, so that the focus error signal F by the CD LD 3e is delayed later than the case of the DVD.
An S-shaped curve of E (1) (FE1 = 1.3 Vp-p),
Focus error signal FE by DVD LD3d
The S-shaped curve (FE4 = 0.5 Vp-p) of (2) occurs (T3).

The levels of these S-shaped curves are as follows:
The data is binarized by the A / D converter 6a and the data is
Via the memory 10.

Next, a method of discriminating the disc type from the S-curve level recorded in the memory 10 will be described with reference to the flowchart shown in FIG.

First, it is checked whether the disk 1 is set (step S1), and if it is set, the focus coil 3c is lowered (step S2). Next, in order to wait for the focus actuator having the focus coil 3c to stabilize, the LD 3e for CD and the LD 3d for DVD are turned on after the elapse of a waiting time of, for example, 10 msec (step S3), and the focus coil 3c is
(Step S4).

Then, the LD 3e for CD generated at the focal point
Peak-to-peak (FEcd) of S-shaped curve
Is read and stored in the memory 10 (step S5). Further, the peak-to-peak (FEdvd) of the S-shaped curve by the DVD LD 3d is read and stored in the memory 10 (step S6). Store the obtained FEcd value in the memory 1
It is read from 0 and compared with a reference value (for example, 1.0 Vp-p) (step S7). If FEcd = 1.0 Vp-p or more, it is determined that the CD is a CD (step S8).

In step S7, FEcd is 1.0 Vp-p
If it is less than FEdvd, the obtained FEdvd value is read from the memory 10 and compared with a reference value (for example, 1.0 Vp-p) (step S9), and FEdvd = 1.0 Vp-p.
If it is the above, it is determined as a DVD (step S10). If the FEdvd value is less than 1.0 Vp-p in step S9, it is determined that the CD-RW is used (step S11).

According to the discrimination method of this embodiment, the CD L
D3e and the LD 3d for DVD emit light simultaneously, and the focus error signal FE obtained by the LD 3e for CD
Since the level of (1) and the level of the focus error signal FE (2) obtained by the DVD LD 3d can be obtained by one up / down of the focus coil,
The determination time can be reduced.

In this embodiment, the CD, DVD, C
Although an example in which only three types of D-RWs are discriminated has been described, even if a CD-R or the like is added, the FEcd after step S7 is performed.
It is possible to make a determination by changing the determination level between FEdvd and FEdvd, or by comparing the FEcd level again after step S9.

In this embodiment, the CD LD 3e and the DVD LD 3d are turned on and off at the same time. However, it is sufficient that the light is emitted stably until the focal point is reached. Can achieve the same effect.

Further, in this embodiment, the LD 3e for CD is used.
And the focus error level obtained by the LD 3d for DVD was determined by comparing with the reference value.
It is also possible to determine from the focus error level ratio obtained by the VD LD 3d depending on the optical characteristics of the pickup. For example, in the case of the example shown in FIG. 3, when the set disc is a CD, FEcd / FEdvd = 1.3 Vp-p / 0.5 Vp-
p = 2.6, and when the set disc is DVD, FEcd / FEdvd = 0.6 Vp-p / 1.3 Vp-
p = 0.38, and when the set disc is a CD-RW, FEcd / FEdvd = 0.3Vp-p / 0.5Vp-
Since p = 0.6, in the determination flow shown in FIG. 4, step S7 is replaced with processing for determining whether or not FEcd / FEdvd> 1, and step S9 is replaced with FEc
By substituting the processing for determining whether or not d / FEdvd <0.5, the discrimination between a CD, a DVD, and a CD-RW can be accurately performed.

In this embodiment, each of the focus error signals F by the LD 3e for CD and the LD 3d for DVD is used.
Since E (1) and FE (2) occur at the same time, these signals are time-divisionally taken in when binarized by the A / D converter 6a. Thus, the A / D converter 6a can be constituted by a single converter.
3e focus error A / D converter and DVD
An A / D converter for focus error by the LD 3d may be provided, and may be constituted by two converters.

In this embodiment, an example has been described in which the type of the disc is determined without moving the position of the pickup 3. However, the discrimination position may be such that a constant voltage is applied to the carriage 4 to another position even on the inner circumference of the disc. , RP signal or TE signal.

(Second Embodiment) FIG. 5 is a block diagram showing a configuration of a recording / reproducing apparatus equipped with an optical recording medium discriminating apparatus according to a second embodiment of the present invention, and FIG. FIG. 2 is a diagram showing a configuration of a pickup 30 according to an embodiment. 1 and 2 are denoted by the same reference numerals,
The description is omitted.

The pickup 30 of the present embodiment differs from the pickup 3 of the first embodiment as shown in FIG.
A focus coil 30d for moving the objective lens 30a for CD and a focus coil 30c for moving the objective lens 30b for DVD are provided, and two focus coils are separately arranged.

Further, these CD focus coils 3
In order to simultaneously drive 0d and the DVD focus coil 30c, a driver circuit 20 is provided in addition to the driver circuit 7 as a focus driver, and the focus drive system is divided into two systems. Then, a constant voltage is generated from the CPU 9 so that the focus coils 30d and 30c
Are simultaneously moved up and down, the same effect as in the first embodiment can be obtained.

The present embodiment is an example in which a separate focus driver is provided for the case where the characteristics of the CD focus coil 30d and the DVD focus coil 30c are different and the two coils cannot be driven simultaneously. However, when the characteristics of these two coils 30d and 30c are not so different and the driving force of the driver 7 can drive the two coils 30d and 30c at the same time,
One driver circuit may be used. Furthermore, two coils 3
If the driver has a driving force even if the characteristics of 0d and 30c are different, for example, the driver 7 and the focus coil 30c
Alternatively, the same effect as described above can be obtained by substituting an attenuator for attenuation (such as resistance division) between 30d and 30d.

(Third Embodiment) FIG. 7 is a block diagram showing a configuration of a recording / reproducing apparatus equipped with an optical recording medium discriminating apparatus according to a third embodiment of the present invention. Are denoted by the same reference numerals, and description thereof is omitted.

In the present embodiment, pickups 41 and 42 for CD and DVD having the same configuration as the conventional apparatus (FIG. 11).
And two focus drive circuits 7 and 20 similar to those of the second embodiment. The second
In the embodiment, as shown in FIG. 6, a method has been described in which one pickup has separate focus coils for CD and DVD, and two discs are simultaneously moved up / down when discs are discriminated. In this embodiment, the disc and the focus coils for CD and DVD are driven at different timings to discriminate the disc.

Hereinafter, the operation of this embodiment will be described in detail with reference to the waveform diagram of FIG.

First, the focus coil for CD (not shown) is lowered, the LD for CD (not shown) emits light (T1 in FIG. 8), and the lowered focus coil is raised toward the disk 1. Go.

When the set disc is a DVD,
S of focus error signal FE (1) by CD LD
A curve (FE2 = 0.6 Vp-p) occurs (T
3). Then, the level of the S-shaped curve is binarized by the A / D converter 6a and stored in the memory 10 via the CPU 9.

Before the end of capturing the focus error signal by the focus coil for CD, (T
2) The DVD focus coil (not shown) is lowered, the LD for the DVD emits light, and the LD 20 is raised toward the disk 1 by the driver 20. At this time, if the set disc is a DVD, the S-shaped curve (FE5 =
1.3 Vpp) (T5). And this S
The level of the curve is binarized by the A / D converter 6a,
The data is stored in the memory 10 via the PU 9.

As shown in FIG. 8, the generation timing of the focus error signal by the LD for CD and the generation timing of the focus error signal by the LD for DVD are generated at the same time because the two focus coils are separately started to rise. Will shift. For this reason, in the second embodiment, when the focus error signal by the CD LD 3e and the focus error signal by the DVD are converted and captured by the A / D converter 6a, time division is performed. Since the timing has been shifted as described above,
There is no need to perform time division, and one A / D converter can sufficiently cope with the problem.

Then, based on the taken focus error signal level, the focus error by the CD LD is compared with the reference value, the focus error by the DVD LD is compared with the reference value, and the focus error by the DVD LD and the reference value are compared. The disc is discriminated by comparing.

According to this embodiment, when the characteristics of the focus coil for CD and the focus coil for DVD are different, in order to accurately capture the focus error signal,
Up / down speed can be set separately.
Further, even when the focus coil up / down operation and the S-curve polarity of the focus error signal are different between the CD and DVD pickups, for example, the CD focus coil takes in the focus error signal at the time of the up, and focuses on the DVD. The coil can also take in the focus error signal at the time of down at once.

Further, in this embodiment, the case where the CD pickup and the DVD pickup are contained in completely different cases has been described. However, even in the configuration shown in FIG. Even if the pickup is housed in one case, the same effect can be obtained by separately driving the focus coils.

Also, the method of discriminating a disc is an LD for a CD.
Alternatively, the magnitude and shape of each focus error signal by the LD for DVD may be compared.

(Fourth Embodiment) FIG. 9 is a structural diagram of a pickup in an optical recording medium discriminating apparatus according to a fourth embodiment of the present invention. It is assumed that the recording / reproducing apparatus of the present embodiment has the same circuit configuration as that shown in FIG.

As shown in FIG. 9, the pickup according to the present embodiment comprises one objective lens and one focus coil, and has a CD LD 3n and a DVD LD 3o. The light beam of the LD 3n for CD is transmitted to the half mirror 3
The light is applied to the disk 1 via the mirror p, the mirror 3q, and the objective lens 31. The objective lens 31 is, for example, optimized at its middle circumference to the CD LD 3n. Then, the reflected light passes through the objective lens 31, the mirror 3 q, and the half mirror 3 p
The light is received by the light receiving element 3u via.

On the other hand, the light beam of the DVD LD 3o passes through the half mirror 3r and the mirror 3s and further passes through only the wavelength plate 3t, which passes only the wavelength of the light beam of the DVD LD 3o.
The light is applied to the disk 1 via the half mirror 3q and the objective lens 31. Here, for example, the outer periphery of the objective lens 3l is optimized for the LD 3o for DVD. Then, the reflected light passes through the objective lens 31, the half mirror 3 q,
The light is received by the light receiving element 3v via the wave plate 3t, the mirror 3s, and the half mirror 3r.

In the present embodiment, since the objective lens and the focus coil are each constituted by one, the first
As in the embodiment, at the same time, the LD is caused to emit light, the focus coil is moved up and down, and a focus error signal by the LD 3n for CD and a focus error signal by the LD 3o for DVD are taken in, and each focus error signal is compared with a reference value. Perform disc discrimination.

Also, the method of discriminating a disc is an LD for CD.
The magnitude and shape of the focus error signal by the 3n and the focus error signal by the DVD LD 3o may be compared.

(Fifth Embodiment) FIG. 10 shows a fifth embodiment of the present invention.
FIG. 3 is a diagram illustrating waveforms of respective units in the optical recording medium determination device according to the embodiment. It is assumed that the recording / reproducing apparatus of the present embodiment has the same circuit configuration as that shown in FIG.

In the first embodiment, the level of the focus error signal is binarized by the A / D converter 6a, the data is stored in the memory 10 via the CPU 9, and the data is compared with a reference value to determine Alternatively, the method of comparing and determining the level of the focus error signal has been described. On the other hand, in the present embodiment, the data stored in the memory 10 is:
Not only the peak-to-peak level, for example, S
Curve shape and upper level (FEcdh, FEdvd
h) and the lower level (FEcdl, FEdvdl) are also stored.

FIG. 10 shows the S of the focus error signal depending on the type of the disk due to the optical characteristics of the pickup.
An example in the case where the vertical balance of the character curve is disturbed is shown. When the disc 1 is a CD, the S-shaped curve of the focus error signal by the CD LD 3e is almost vertically symmetrical, and FEcdh = 0.65Vp-p FEcdl = 0.65Vp-p.

On the other hand, the S-curve of the focus error signal by the DVD LD 3d is not vertically symmetric, and FEdvdh = 0.1Vp-p FEdvdl = 0.4Vp-p.

In this case, since the vertical ratio of the S-shaped curve of the focus error signal by the DVD LD 3d is FEdvdh / FEdvdl = 0.25, the disc is determined with reference to this ratio.

In this embodiment, when the level difference between the peak-to-peak levels of the focus error S-curve is small and it is difficult to determine only by the level difference, the shape is referred to instead of the level alone. Therefore, more accurate determination can be made. This embodiment has been described in the first embodiment, but the same effects can be obtained in other embodiments.

[0093]

As described in detail above, according to the first aspect, it is possible to quickly and accurately determine the types of information recording media having different thicknesses and optical reflectivities.

According to the second aspect, the same effect as that of the first aspect can be obtained in a configuration in which the first and second objective lenses can be moved independently.

According to the third aspect of the invention, in addition to the same effect as the first aspect of the invention, since the generation timing of each focus error signal can be shifted, the time division of each focus error signal can be reduced. No longer needed
The configuration can be simplified.

According to the fourth aspect, in addition to the same effect as the first aspect, the moving speeds of the first and second objective lenses can be set separately, so that the focus error signal can be accurately obtained. It becomes possible to take in.

According to the fifth aspect of the present invention, in a pickup configuration having an objective lens for forming a focal point of the first and second light beams on the optical axis of the first and second light beams, a pickup similar to the first invention is provided. It works.

According to the sixth invention, in the first to fifth inventions, the signal level stored in the storage means is compared with the reference value to determine the type of the information recording medium. The type of the recording medium can be easily and accurately determined.

According to the seventh invention, in the first to fifth inventions, the signal level stored in the storage means is compared with a reference value, and further, the shape of each S-curve is compared. Since the type of the information recording medium is determined based on the result, it is possible to more accurately determine the type of the information recording medium.

According to the eighth aspect, in the first to fifth aspects, the type of the information recording medium is determined from the signal level of each S-curve stored in the storage means. It is possible to easily and accurately determine the type of the medium.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a recording / reproducing apparatus equipped with an optical recording medium discriminating apparatus according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a pickup 3 shown in FIG.

FIG. 3 is a diagram illustrating waveforms of respective units according to the first embodiment.

FIG. 4 is a flowchart illustrating a disc determination method according to the first embodiment.

FIG. 5 is a block diagram showing a configuration of a recording / reproducing apparatus equipped with an optical recording medium discriminating apparatus according to a second embodiment of the present invention.

FIG. 6 is a diagram illustrating a configuration of a pickup according to a second embodiment.

FIG. 7 is a block diagram showing a configuration of a recording / reproducing apparatus equipped with an optical recording medium discriminating apparatus according to a third embodiment of the present invention.

FIG. 8 is a waveform chart of each part of the third embodiment.

FIG. 9 is a structural diagram of a pickup in an optical recording medium discriminating apparatus according to a fourth embodiment of the present invention.

FIG. 10 is a diagram showing waveforms of respective units in an optical recording medium discriminating apparatus according to a fifth embodiment of the present invention.

FIG. 11 is a block diagram showing a configuration of a conventional recording / reproducing apparatus.

FIG. 12 is a waveform chart for explaining a disc discriminating method in the first conventional example.

FIG. 13 is a view showing a structure of a pickup in a second conventional example.

FIG. 14 is a waveform chart for explaining a disc discriminating method in a second conventional example.

[Description of Signs] 1 Disc 3, 30, 41, 42 Pickup 3a, 3b, 3l, 30a, 30b Objective Lens 3c, 3m, 30c, 30d Focus Coil 3d, 3e, 3n, 3o, 30e, 30f Light Emitting Element 3j, 3k, 3u, 3v, 30k, 30l Photodetector 5 Preamplifier 9 CPU 10 Memory

Claims (9)

[Claims] 1. A first light beam lighting means for lighting a first light beam applied to an information recording surface of the first information recording medium to reproduce recorded information from the first information recording medium; A first objective lens for forming a focal point of the light beam on the optical axis of the first light beam, and a second information recording medium for reproducing recorded information from a second information recording medium A second light beam lighting means for lighting a second light beam applied to the information recording surface of the second light beam; and a second object for forming a focal point of the light beam on the optical axis of the second light beam. The first and second objectives for changing a relative distance parallel to the optical axis between a lens, the first and second objective lenses, and an information recording surface of the first or second information recording medium. A lens moving means for moving a lens; First and second light receiving means for receiving light reflected from the information recording surface by the second light beam and outputting the first and second light receiving signals, respectively, and the first and second light receiving means. Focus error signal generating means for generating a focus error signal corresponding to the first and second light receiving signals based on the signal; and an RF signal generating means for generating an RF signal corresponding to the first and second light receiving signals Means, a pickup having the first and second light beam lighting means, the first and second objective lenses, the lens moving means, and the first and second light receiving means, inside and outside the information recording surface. An optical recording medium discriminating device comprising: a pickup moving unit for moving the first and second objective lenses simultaneously, wherein the first and second light beams are simultaneously turned on, and the first and second objective lenses are simultaneously moved. Control means for causing the focus error signal to be generated at each of the focus positions of the first and second light beams; and storage means for storing the first and second information from the focus error signal stored in the storage means. An optical recording medium discriminating apparatus, comprising: a discriminating means for discriminating a type of a recording medium. 2. A first light beam lighting means for lighting a first light beam applied to an information recording surface of the first information recording medium to reproduce recorded information from the first information recording medium; A first objective lens for forming a focal point of the light beam on the optical axis of the first light beam, and a second information recording medium for reproducing recorded information from a second information recording medium A second light beam lighting means for lighting a second light beam applied to the information recording surface of the second light beam; and a second object for forming a focal point of the light beam on the optical axis of the second light beam. Moving the first objective lens to change a relative distance parallel to the optical axis between a lens, the first objective lens, and an information recording surface of the first or second information recording medium; Lens moving means, the second objective lens and the first or second information A second lens moving unit for moving the second objective lens to change a relative distance parallel to the optical axis with an information recording surface of a recording medium; and a second lens moving unit for moving the second objective lens. First and second light receiving means for receiving light reflected from the information recording surface by the first and second light beams and outputting respective first and second light receiving signals in accordance with a change in the relative distance. A focus error signal generating means for generating a focus error signal corresponding to the first and second light receiving signals based on the first and second light receiving signals; RF signal generating means for generating a corresponding RF signal, the first and second light beam lighting means, the first and second light beam lighting means,
An optical recording medium comprising: an objective lens, a pickup moving means for moving a pickup having the first and second lens moving means and the first and second light receiving means to an inner and outer periphery of the information recording surface. Control means for simultaneously turning on said first and second light beams and simultaneously moving said first and second objective lenses; and a control means for combining said first and second light beams. Storage means for storing a focus error signal generated at each focus position; and discrimination means for discriminating the types of the first and second information recording media from the focus error signal stored in the storage means. For determining an optical recording medium. 3. A first light beam lighting means for lighting a first light beam applied to an information recording surface of the first information recording medium for reproducing recorded information from the first information recording medium; A first objective lens for forming a focal point of the light beam on the optical axis of the first light beam, and a second information recording medium for reproducing recorded information from a second information recording medium A second light beam lighting means for lighting a second light beam applied to the information recording surface of the second light beam; and a second object for forming a focal point of the light beam on the optical axis of the second light beam. Moving the first objective lens to change a relative distance parallel to the optical axis between a lens, the first objective lens, and an information recording surface of the first or second information recording medium; Lens moving means, the second objective lens and the first or second information A second lens moving unit for moving the second objective lens to change a relative distance parallel to the optical axis with an information recording surface of a recording medium; and a second lens moving unit for moving the second objective lens. First and second light receiving means for receiving light reflected from the information recording surface by the first and second light beams and outputting respective first and second light receiving signals in accordance with a change in the relative distance. A focus error signal generating means for generating a focus error signal corresponding to the first and second light receiving signals based on the first and second light receiving signals; RF signal generating means for generating a corresponding RF signal, the first and second light beam lighting means, the first and second light beam lighting means,
An optical recording medium comprising: an objective lens, a pickup moving means for moving a pickup having the first and second lens moving means and the first and second light receiving means to an inner and outer periphery of the information recording surface. The first light beam is turned on and the first objective lens is moved, and the second light beam is turned on before turning off the first light beam thereafter; Control means for moving the second objective lens; storage means for storing focus error signals respectively generated at the in-focus positions of the first and second light beams; and focus error signals stored in the storage means. A discriminating means for discriminating the types of the first and second information recording media; 4. A first light beam lighting means for lighting a first light beam for reproducing recorded information from a first information recording medium; and a light beam on the optical axis of the first light beam. A first objective lens for forming a focal point, a second light beam lighting unit for lighting a second light beam for reproducing recorded information from a second information recording medium, and the second light beam A second focus for forming a focal point of the light beam on the optical axis of the beam;
Moving the first objective lens to change a relative distance parallel to the optical axis between the first objective lens and the information recording surface of the first or second information recording medium. First lens moving means, and the second objective lens for changing a relative distance parallel to the optical axis between the second objective lens and an information recording surface of the first or second information recording medium. Receiving the reflected light from the information recording surface by the first and second light beams in accordance with the change in the relative distance by the second lens moving means for moving the first lens and the second lens moving means First and second light receiving means for outputting respective first and second light receiving signals,
A focus error signal generating unit for generating a focus error signal corresponding to the first and second light receiving signals based on the first and second light receiving signals; and a focus error signal generating unit corresponding to the first and second light receiving signals. RF signal generating means for generating an RF signal; the first and second light beam lighting means; the first and second objective lenses; the first and second lens moving means; and the first and second lens moving means. An optical recording medium discriminating device comprising: a pickup moving means for moving a pickup having light receiving means to the inner and outer peripheries of the information recording surface, wherein the first and second light beams are turned on simultaneously or separately. Control means for moving the second objective lens at a speed different from the moving speed of the first objective lens after or simultaneously with or after moving the first objective lens; Storage means for storing a focus error signal generated at each in-focus position of the second light beam; and discrimination means for discriminating the types of the first and second information recording media from the focus error signal stored in the storage means. An optical recording medium discriminating device comprising: 5. A first light beam lighting means for lighting a first light beam applied to an information recording surface of the first information recording medium in order to reproduce recorded information from the first information recording medium; A second light beam lighting means for lighting a second light beam applied to an information recording surface of the second information recording medium to reproduce recorded information from the second information recording medium; An objective lens for forming a focal point of the light beam on the optical axis of the second light beam; and the objective lens and the first lens.
Or a lens moving means for moving the objective lens to change a relative distance parallel to the optical axis with the information recording surface of the second information recording medium; A light separating means for separating each reflected light from the information recording surface by the two light beams, and a first and a second light receiving signal for outputting first and second light receiving signals corresponding to the respective reflected lights received via the light separating means. First and second light receiving means; focus error signal generating means for generating a focus error signal corresponding to the first and second light receiving signals based on the first and second light receiving signals; Signal generating means for generating an RF signal corresponding to the first and second light receiving signals, the first and second light beam lighting means, the objective lens, the lens moving means, and the first and second light receiving means Have An optical recording medium discriminating device comprising: a pickup moving means for moving a pickup to the inner and outer peripheries of the information recording surface, wherein the first and second light beams are simultaneously turned on and the objective lens is Control means for simultaneously moving; a storage means for storing a focus error signal generated at each of the focus positions of the first and second light beams; and a first and a second based on the focus error signal stored in the storage means. And a discriminating means for discriminating the type of the information recording medium. 6. The storage unit stores a peak-to-peak level of an S-shaped curve in a focus error signal generated at each of the focus positions of the first and second light beams. Wherein the signal level stored in the storage means is compared with a reference value to determine the type of the first and second information recording media.
An optical recording medium discriminating apparatus according to claim 5. 7. The S-shaped curve peak-to-peak level and the shape of each of the S-shaped curves in the focus error signal generated at the in-focus position of the first and second light beams, respectively. The discrimination means compares the signal level stored in the storage means with a reference value, compares the shape of each of the S-shaped curves, and based on these comparison results, the first and second 6. The optical recording medium discriminating apparatus according to claim 1, wherein the type of the information recording medium is determined. 8. The storage means stores a peak-to-peak level of an S-shaped curve in a focus error signal generated at each of the focus positions of the first and second light beams, 2. The apparatus according to claim 1, wherein the type of said first and second information recording media is determined from the signal level of each S-shaped curve stored in said storage means.
An optical recording medium discriminating apparatus according to claim 5. 9. A first light beam lighting means for lighting a first light beam applied to an information recording surface of the first information recording medium to reproduce recorded information from the first information recording medium. A first objective lens for forming a focal point of the light beam on the optical axis of the first light beam, and a second information recording medium for reproducing recorded information from a second information recording medium A second light beam lighting means for lighting a second light beam applied to the information recording surface of the second light beam; and a second object for forming a focal point of the light beam on the optical axis of the second light beam. A lens is provided, and the first and second light beams are simultaneously turned on, and the optical axis between the first and second objective lenses and the information recording surface of the first or second information recording medium is provided. Moving the first and second objective lenses simultaneously to change the relative distance parallel to Receiving the light reflected from the information recording surface by the first and second light beams and outputting first and second light receiving signals, respectively, with the change in the relative distance; A focus error signal corresponding to the first and second light receiving signals is generated based on the second light receiving signal, and a focus error signal generated at each of the focus positions of the first and second light beams is stored. An optical recording medium discriminating method for discriminating the types of the first and second information recording media from a focus error signal stored in the storage unit.