JPH1064179A - Optical recording medium discriminating device, and optical recording and reproducing device equipped with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely discriminate the kind of an optical recording medium in a short time without leaving a flaw or an unrecoverable trace on the optical recording medium and yet to enable the manufacture of an optical recording medium discriminating means at a low cost. SOLUTION: To a carriage 20, a light source sensor 30 constituting a part of a reflecting surface detecting means is attached so as to be positioned side by side with an optical head 21. This light source sensor 30 is composed of a light emitting part 31 consisting of a light emitting diode and a light receiving part 32 consisting of a photodiode, etc., adjacent to this light emitting part 31 in the radial direction (tracking direction) of the disk medium.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording medium discriminating apparatus and an optical recording / reproducing apparatus using the same, and more particularly to a technique suitable for an optical recording / reproducing apparatus which can handle a plurality of types of optical recording media.

[0002]

2. Description of the Related Art At present, various optical recording media and optical recording / reproducing apparatuses are commercially available. In particular, various types of detachable optical recording media are used. For example, as an optical recording medium, a CD-ROM (Compact Disk-Read only)
memory), CD-R (Compact Disk-Recordable) and the like, and DVD (Digital Video Disk) has also been developed.

[0003] Each of these various optical recording media has advantages and disadvantages. From the viewpoint of the user, it is desired that a plurality of optical recording media be properly used as needed. However, providing separate drive devices corresponding to the respective optical recording media, that is, optical recording / reproducing devices, is disadvantageous in terms of cost and installation location, and is also difficult to use.

Therefore, recently, an optical recording / reproducing apparatus corresponding to a plurality of types of optical recording media has been actively developed. For example, various optical recording / reproducing apparatuses have been proposed to support two optical recording media, CD-ROM and DVD. As a method for dealing with a plurality of types of optical recording media, a method using a bifocal lens constituted by a hybrid lens or a hologram as an objective lens of an optical head, a method using two objective lenses by switching an optical path, a method using a single lens, There are a type in which two objective lenses are switched for use in the optical path, a type in which two light sources are switched, and a type in which the aperture of the light beam is changed by aperture limiting means.

[0005]

However, in the above-mentioned optical recording / reproducing apparatus, for example, in order to discriminate between a CD and a DVD, a focus search is performed by an optical head, a focus is detected, and the thickness of the disc is determined. It is necessary to determine the disc size and to perform the switching operation according to the above-described method in accordance with the result of the determination, so that it takes a long time to discriminate the disc. Moreover, if the first switching state corresponds to a different type of disk from the loaded disk, after switching the state of the optical head, it is necessary to determine again whether or not the disk is another disk. This may not be the case, so it may take longer.

[0008] As shown in FIG. 8, C shown in FIG.
In the case of DVD shown by D or Y in the figure, the reflectance of the recording surface shows almost the same high value over a relatively wide frequency range, but in the case of CD-R shown by Z in the figure, the recording surface is C
It has a high reflectivity for light having a recording / reproducing wavelength of 780 nm for D, but has a considerably low reflectivity for light having a recording / reproducing wavelength of 650 nm for DVD. Therefore, when a CD-R is inserted into an optical recording / reproducing apparatus, the reflectance of the recording surface is extremely reduced with light having a wavelength of 650 nm used for DVD, so that the amount of reflected light required for obtaining a servo error signal cannot be secured. There is a problem. Moreover, since the reflectance of the recording surface of the CD-R is low, the absorptivity of light energy is high, and recording is performed on the recording surface even with low power, and the recording area cannot be used thereafter. .

SUMMARY OF THE INVENTION Accordingly, the present invention is to solve the above-mentioned problems, and its object is to make it possible to reliably determine the type of the optical recording medium in a short period of time, and to prevent damage or irreparable traces on the optical recording medium. An object of the present invention is to realize an optical recording medium discriminating means which can be manufactured at a low cost without leaving the optical recording medium and an optical recording / reproducing apparatus using the same.

[0008]

Means taken by the present invention to solve the above-mentioned problem is a recording medium discriminating apparatus used in an optical recording / reproducing apparatus for recording and / or reproducing information on / from an optical recording medium. In addition, apart from an optical head for recording and / or reproducing information on and from the optical recording medium, a reflection surface detecting means for optically detecting a position of the reflection surface of the optical recording medium in a thickness direction is provided. Wherein the optical recording medium is determined based on the position of the reflection surface detected by the reflection surface detection means.

According to this means, the optical recording medium can be reliably determined based on the position in the thickness direction of the reflection surface detected by the reflection surface detection means, and the reflection surface detection means is provided separately from the optical head. By being
Since the detection can be performed in parallel with the operation of the optical head, the detection can be completed in a short time.

The above-mentioned reflection surface includes any optically detectable reflection surface in addition to the recording surface of the optical recording medium. Further, the determination of the optical recording medium is not limited to the determination of the type, but includes the determination of the front and back sides and the determination of various optical recording media having different reflection surface positions.

Here, the position of the reflection surface is measured by the reflection surface detecting means within a period from when the optical recording medium is mounted on the optical recording / reproducing apparatus to when light irradiation is performed by the optical head, It is preferable to determine the optical recording medium.

According to this means, since the determination of the optical recording medium is completed before the optical head starts the operation of accessing the optical recording medium, the optical head is adjusted to the determined optical recording medium without performing useless operation. The optical recording / reproducing apparatus can be operated by using the optical recording / reproducing apparatus, the initial operation of the optical recording / reproducing apparatus can be performed quickly, and the optical recording medium can be identified before the optical recording medium is irradiated with light from the optical head. , An optical recording medium that may be damaged by light irradiation such as a CD-R can be prevented.

[0013] The reflecting surface detecting means may include a light emitting unit for irradiating the optical recording medium with light, and a detecting position or a detecting range of reflected light from the reflecting surface obtained by irradiating the light emitting unit with light. It is preferable that the light-receiving unit further include a light-receiving unit for detecting, and that the position in the thickness direction of the reflection surface is detected based on the detection position or the detection range of the reflected light.

According to this means, the position of the reflecting surface in the thickness direction can be easily detected with a simple configuration by combining the light emitting section and the light receiving section.

When the detection position or the detection range of the reflected light is detected, the light irradiation direction of the light emitting unit is set obliquely with respect to the reflection surface, and the detection of the reflected light is performed according to the position in the thickness direction of the reflection surface. The principle that the position or the detection range moves may be used, or the principle that the detection range expands or contracts by increasing or decreasing the spread of the reflected light depending on the position of the reflection surface in the thickness direction may be used.

[0016] In this case, the light receiving section includes at least two light detecting sections for detecting the reflected light, and based on a difference in the amount of light detected by the light detecting section, the position of detecting the reflected light or the position of the reflected light. It is desirable to be configured to detect the detection range.

According to this means, the detection position or the detection range of the reflected light is detected based on the difference between the detected light amounts of the two or more light detection units, so that the stability of detection with respect to noise can be improved, and Detection can be prevented.

In this case, it is preferable that a condensing means for the light emitted from the light emitting unit is provided between the light emitting unit and the optical recording medium.

According to this means, the spread of the light beam emitted from the light emitting section can be limited by the light condensing means.
Detection accuracy and detection intensity can be increased.

At this time, for an optical recording medium far from the reflection surface, the focal position of the light condensing means is set so as to be closer to the optical recording medium than the light receiving position of the light receiving section. It is effective that the focal position of the light condensing means is set so as to be closer to the optical recording medium than the light receiving position of the light receiving unit with respect to the optical recording medium close to the optical recording medium.

According to this means, since the focal position of the light condensing means is set so as to be located before and after the light receiving section depending on the type of the optical recording medium, the spread of the reflected light in the light receiving section is extremely widened. Can be prevented.

At this time, it is effective that the light emitting section, the light receiving section and the light collecting means are integrated by a resin mold, and the light collecting means is formed by the resin mold.

The size can be reduced because the components are integrated by the resin mold, the handling such as assembling and replacement is easy, and the number of parts is reduced because the light collecting means is constituted by the resin mold itself. Therefore, the manufacturing cost can be reduced.

Further, it is preferable that the type of the optical recording medium is determined based on the position of the reflection surface in the thickness direction and the amount of reflected light detected by the light receiving section.

According to this means, the type of the optical recording medium can be determined not only by the position of the reflecting surface in the thickness direction but also by the amount of reflected light. It is possible to make a determination.

Preferably, the type and front / back of the optical recording medium are determined based on the position in the thickness direction of the reflection surface detected by the reflection surface detection means.

According to this means, in addition to the type of the optical recording medium, it is possible to determine whether the optical recording medium is front or back.

It is preferable that the reflection surface detecting means detects the inclination angle of the reflection surface and detects the inclination of the reflection surface.

By detecting the inclination angle of the reflection surface, it becomes possible to control the attitude of the optical head in order to more reliably perform the recording / reproducing operation by the optical head.

Next, in an optical recording / reproducing apparatus which performs recording and / or reproduction on an optical recording medium, an optical head for recording and / or reproducing on the optical recording medium, Reflecting surface detecting means for optically detecting the position of the reflecting surface in the thickness direction, and determining means for determining the optical recording medium based on the position of the reflecting surface detected by the reflecting surface detecting means, There is a case where the optical head or the access method of the optical head is switched according to the result of the determination by the determining means.

Here, it is preferable that the determination means is configured to determine the optical recording medium based on the position of the reflection surface and the amount of reflected light detected by the reflection surface detection means.

Preferably, the determination means is configured to determine the type and front / back of the optical recording medium based on a position in the thickness direction of the reflection surface detected by the reflection surface detection means.

Further, it is preferable that the reflection surface detecting means detects the inclination angle of the reflection surface and drives the optical head in accordance with the inclination angle.

[0034]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of an optical recording medium discriminating means and an optical recording / reproducing apparatus using the same will be described with reference to the accompanying drawings. FIG. 1 is an explanatory diagram showing a schematic configuration of the optical recording / reproducing apparatus of the present embodiment. The optical disk 10 is, for example, a CD-ROM, a CD-R,
DE (Compact Disk-Erasable), DVD (one recording layer), DVD (two recording layers), DV
DR (Digital Video Disk-Recordable), DVD-
ROM (Digital Video Disk-Read Only Memory)
), DVD-RAM (Digital Video Disk-Random A)
ccess Memory).

Of the above-mentioned plurality of types of optical discs 10, C
In D, the thickness from the light incident surface to the recording surface is 1.2 mm, and the recording / reproducing wavelength is 780 nm.
In D, the thickness from the light incident surface to the recording surface is 0.6
mm, and the recording / reproducing wavelength is 650 nm. The optical disk 10 shown in FIG. 1 basically represents a DVD, and has a recording surface 10a substantially at the center in the thickness direction of the disk.

The optical head 21 is mounted on a carriage 20, and the carriage 20 is configured to be movable by a voice coil motor or the like along a guide shaft 22 fixed in a radial direction of the disk. In the optical head 21,
An internal mechanism (not shown) is provided which can move slightly with respect to the carriage 20 in both the focusing direction, which is the vertical direction in the figure, and the tracking direction, which is the horizontal direction in the figure. Recording and reproduction are performed while being controlled by a servo.

The carriage 20 is provided with a light source sensor 30 which constitutes a part of the reflection surface detecting means so as to be aligned with the optical head 21. The light source sensor 30 includes a light emitting unit 31 formed of a light emitting diode, and a light receiving unit 32 formed of a photodiode or the like adjacent to the light emitting unit 31 in a disk radial direction (tracking direction).

FIG. 2 shows the optical sensor 30 in an enlarged manner.
(A) and (b). Optical disk 10 of FIG.
Is a recording surface 10a such as a DVD as shown in FIG.
Is located close to the light incident surface of the disc,
The optical disk 10 shown in FIG. 2B has a recording surface 10a located far from the light incident surface of the disk, such as a CD-ROM.

The optical path of the light emitted from the light emitting section 31 is set so as to advance in a direction having an inclination angle θ in the radial direction with respect to the recording surface 10a of the optical disk 10. With respect to the light emitting section 31, the two light detecting sections 32A and 32 constituting the light receiving section 32 are arranged in the inclination direction of the optical path.
B are arranged.

When the recording surface 10a is close to the light incident surface as shown in FIG. 2 (a), the center of the reflected light from the recording surface is directed to the light detecting portion 32A close to the light emitting portion 31. )
When the recording surface 10a is distant, the center of the reflected light is directed to the light detection unit 32B as shown in FIG. Therefore, by comparing the light receiving intensities of the photodetectors 32A and 32B, it is possible to know which structure the optical disc 10 has been loaded.

The number of light detecting sections in the light receiving section 32 is arbitrary, and can be provided as needed. Further, the light receiving section 32 may be constituted by a split diode having two or more light detecting sections. Further, the inclination direction of the optical path of the light emitted from the light emitting unit 31 and the arrangement direction of the light emitting unit 31 and the light receiving unit 32 may be a direction other than the radial direction of the optical disc 10.

FIG. 3 shows that the optical sensor 30 is provided with a condenser lens 3.
3 is provided. This condenser lens 33
Is arranged between the light emitting unit 31 and the optical disc 10 so as to condense the light emitted from the light emitting unit 31 and irradiate the recording surface 10a of the optical disc. Condensing lens 33
Is generally set to a distance that is approximately the same as the optical path length that travels from the light emitting section 31 to the recording surface of the optical disk, is reflected and returns to the light receiving section 32. This is because the light emitted from the light emitting unit 31 can be detected most efficiently and accurately in the light receiving unit 32.

However, as shown in FIGS. 3A and 3B, when the position of the recording surface 10a of the optical disk 10 changes, the focus positions F1 and F2 with respect to the light receiving portion 32 are changed.
Changes greatly. Therefore, any optical disk 10
In order to suppress the spread of the reflected light as much as possible in the vicinity of the light receiving portion 32 even when the optical sensor 3 is loaded, as shown in FIG.
When the distance is close to 0, the focal position F1 is closer to the recording surface 10a of the optical disc 10 than the light receiving unit 32. When the recording surface 10a is far, the focal position F2 is closer to the recording surface 10a than the light receiving unit 32. Preferably, there is.

In this way, in any of the cases shown in FIGS. 3A and 3B, the spread of the reflected light can be suppressed, so that the intensity of the reflected light can be easily maintained. Detection accuracy can be improved, and detection errors can be reduced.

FIG. 9 shows an example of a signal processing circuit applicable to each of the above embodiments. This signal processing circuit
The photocurrents generated by the two photodiodes forming the light detection units 32A and 32B of the light receiving unit 32 are converted into output potentials corresponding to the photocurrents by current-voltage conversion units 41A and 41B forming an integration circuit. Then, a differential amplifier 42A that takes a difference between these two output potentials and an addition amplifier 42B that takes a sum of the two output potentials are provided.

The difference output output from the differential amplifier 42A is input to an AGC (auto gain control) circuit 43, normalized by the sum output output from the addition amplifier 42B, and output from the output terminal 44 as a normalized difference output. Is done. The sum output is output from the output terminal 45 as it is.

FIG. 10 is a plot of the above-described normalized difference output with respect to the distance from the light incident surface of the optical disk to the recording surface. In the figure, E indicates the position of the recording surface of the DVD,
In the figure, F indicates the position of the recording surface of the CD. In this way, it is possible to distinguish between a CD and a DVD based on the value of the normalized difference output.

FIG. 11 shows a judgment circuit in this case, in which the normalized difference output of the output terminal 44 is input to the comparator 47 together with the comparator level potential 46, and the output terminal 48 outputs a binary potential. It is configured.
For example, when the normalized difference output is higher than the compare level potential 46, the potential of the output terminal 48 becomes high level "H", and it is detected that the optical disk is a DVD. When the normalized difference output is lower than the compare level potential 46, the potential of the output potential 48 becomes low level “L”.
And it is detected that the optical disk is a CD.

FIG. 12 shows a judgment circuit connected to the output terminal 45 for outputting the sum output shown in FIG.
The circuit portion for outputting the sum output of the signal processing circuit and the determination circuit shown in FIG. 12 are circuits for determining the optical disk based on the reflectance of the recording surface. In the present embodiment, a discrimination function based on reflectance is added to the above-described discrimination of an optical disk by detecting the position of the recording surface, whereby discs having the same recording surface position but different types can be recorded. It is possible to discriminate different types of discs that do not slightly enter the surface position.

In the present embodiment, the light emitting section 31 is 600 to 7
The optical recording medium emits light having a wavelength of 00 nm (for example, 650 nm). By detecting the reflected light in the light receiving section 32, an optical recording medium having a recording surface having different reflectances in the wavelength band can be obtained. Can be determined. For example, a CD-ROM or DVD and a CD-R
As shown in FIG. 8, since the reflectivity is largely different in the wavelength band of 600 to 700 nm, the two can be clearly distinguished by detecting the amount of reflected light.

The output terminal 45 is connected to a comparator 51. The comparator 51 compares the first comparator level potential 53 with the sum output of the output terminal 45, and as a result, outputs a binary first comparator output. Output terminal 55
Output to On the other hand, the comparator 52 is connected to the output terminal 45
Output from the second comparator level potential 5
4 and outputs a binary second comparator output to the output terminal 54 as a result.

Here, the first compare level potential 53
Is set higher than the second compare level potential 54. The sum output output to the output terminal 45 essentially indicates the total amount of reflected light detected by the light receiving section 32, and takes different values depending on the reflectance of the recording surface of the optical disk. Therefore, the first compare level potential 5
By setting 3 and the second compare level potential 54 as appropriate, it is possible to discriminate an optical disk having a recording surface having three or more different reflectivities.

That is, in the present embodiment, the first compare level potential 53 is set to the CD, CD-ROM, D
VD (one layer recording surface), DVD-
It is lower than the sum output obtained by the reflectivity of the recording surface of the ROM, and is lower than the recording surface of the CD-E, CD-R, DVD (having a two-layer recording surface), DVD-R, and DVD-RAM. It is set higher than the sum output obtained by the reflectance, and the second comparator level potential 54 is set to CD, CD−
ROM, CD-E, DVD (one having a single-layer recording surface and one having a two-layer recording surface), D
The sum output can be set lower than the sum output obtained by the reflectance of the recording surface of the VD-ROM and DVD-R, and higher than the sum output obtained by the recording surface of the CD-R and DVD-RAM.

By setting the first compare level potential 53 and the second compare level potential 54 as described above, a plurality of optical recording media can be determined as follows.

[0055]

[Table 1]

The above two comparator level potentials 53,
54 is appropriately determined according to the type of the optical disk that needs to be distinguishable from the reflectance of the recording surface, but the number of the comparator level potentials can also be set appropriately according to the number of types of the optical disk that need to be determined. it can.
For example, when there are only two types of optical disks that need to be determined based on the reflectance, the compare level potential may be single.

FIG. 4 shows that the light receiving section 32 is set at the inclination angle θ.
Is replaced with an optical linear sensor 34 extending in the inclination direction. The optical linear sensor 34 changes the potential difference in the extension direction substantially linearly by moving the position where the reflected light is incident. This optical linear sensor 34
, The signal processing circuit can be simplified, and a recording surface formed at an arbitrary position can be detected.

FIG. 5 shows a structure in which the optical sensor 30 is formed integrally with a resin mold. The optical sensor 30 can be configured by a light emitting element and a light receiving element mounted on a single semiconductor chip, and it is desirable that the optical sensor be formed by molding the outside with a resin if possible. In this case, as shown in FIG. 5A, the light sensor 30 and the light receiving unit 32 are integrally sealed with a resin mold 35 in a state where the light emitting surface and the light receiving surface are optically exposed. The four terminals 36 protrude from the side surface of the resin mold 35. Further, this resin also has an optical filter function of transmitting only the wavelength of the light emitting section. As a result, the resin mold 35 covering the light receiving unit 32 transmits only the light emitted from the light emitting unit 31, so that the light receiving unit 32 is subjected to disturbance due to intrusion of light having a wavelength other than the wavelength of the light emitted from the light emitting unit 31. Disappears.

The resin mold 35 is, for example, a transparent wrapping around the outside of a semiconductor chip (IC chip) on which a light emitting diode, a two-part photodiode, a signal processing circuit and a judgment circuit (these constitute a reflection surface detecting means) are formed. It is preferably a resin. In this case, the light emitting surface of the light emitting diode and the light receiving surface of the photodiode can be configured to be covered with a thin transparent resin mold film. Also,
By forming the transparent resin covering the light emitting surface of the light emitting diode into a lens shape, a lens portion 35 a having a function equivalent to that of the above condensing lens 33 can be configured by a part of the resin mold 35.

FIG. 5 (b) shows the resin mold 3
A hologram 35b is formed on the light emitting surface of the light emitting diode No. 5 and the hologram 35b is used to form the condensing lens 33.
It is intended to have the same light condensing function as described above.

FIG. 6 shows another example of the structure of the integrated optical sensor 30 shown in FIG. This optical sensor 30
5A, in the basic structure shown in FIG. 5A, the four light detection sections 32A-1, 32A-2, 32B-1, and 32 are provided on the light receiving section 32 sealed by the resin mold 35.
B-2 is provided. Here, the arrow R in FIG. 5 indicates the radial direction (radial direction) of the optical disk, and the arrow T indicates the tangential direction (tangential direction of rotation) of the optical disk.

In the optical sensor 30 shown in FIG. 6, since four light detecting sections are provided adjacent to both the radial direction and the tangential direction, the reflected light moves in any direction. Can be detected.

For example, the photodetectors 32A-1, 32A-2 and 32B-1, 32B-2 arranged in the tangential direction.
The distance of the recording surface can be determined based on the difference in the amount of received light. Here, each of the two photodetectors 32A
By adding the light receiving signals of -1 and 32A-2 or 32B-1 and 32B-2, and taking the difference between the added values, it is possible to accurately determine the distance of the recording surface.

On the other hand, the light detectors 32A arranged in the radial direction
Based on the difference in the amount of received light between -1, 32B-1 and 32A-2, 32B-2, it is possible to detect the inclination of the recording surface due to the bowl-shaped warpage or distortion of the optical disk. Optical recording media such as optical discs are usually slightly deformed in a bowl shape, albeit slightly, and this deformation causes the recording surface to be inclined, causing coma aberration in the light spot of the optical head. I do. In order to prevent this, in the present embodiment,
The inclination of the recording surface is also measured by the optical sensor 30, and the lens skew actuator of the optical head is controlled according to the measurement result, so that the optical axis of the light beam emitted from the optical head is always perpendicular to the recording surface. So hold.

FIG. 7 shows a method for detecting the inclination angle of the recording surface of the optical disk. As shown in FIG. 7A, of the four photodetectors, for example, when the recording surface of the optical disk is vertical (perpendicular to the optical axis of the light emitted from the optical head), the recording surface is When a closer DVD is loaded, reflected light due to light emitted from the light emitting unit is received in the area A. When a CD-ROM whose recording surface is farther from the optical sensor 30 is loaded, the reflected light becomes Light is received in region B. At this time, the areas A and B are
The light detectors 32A-1 and 32A-2, or 3
2B-1 and 32B-2.
The reflected light impinges on the three photodetectors almost uniformly.

However, when the optical disk is curved and the recording surface is inclined in the radial direction, the areas A and B of the reflected light are shifted right and left as indicated by the dotted lines in each case. This shift is determined by the difference in the amount of received light between the light detectors 32A-1 and 32A-2, or the difference between the light detectors 32B-1 and 32B-.
2 can be detected based on the difference in the amount of received light. FIG. 7B shows the relationship between the tilt output (V) indicating the tilt of the recording surface obtained by such a difference in the amount of received light between the photodetectors and the tilt (degree) of the recording surface of the optical disc. .

As shown in FIG. 7B, the relationship between the inclination output and the inclination of the recording surface can be obtained in advance by calculation or experiment. The inclination angle can be detected. By controlling the lens skew actuator based on this, the optical head can always be kept in a proper posture with respect to the recording surface.

FIG. 13 shows the flow of control signals when the above-described optical recording medium discriminating apparatus is applied to an optical recording / reproducing apparatus. The disc discriminating unit 60 includes the above-described optical sensor 30, a signal processing circuit, and a judging circuit, and outputs the above-described comparator output, first comparator output, and second comparator output each formed of a binary signal. The signals are output from the output terminals 48, 53, 54 to the control circuit 61.

The control circuit 61 sends a control signal corresponding to the signal output from the output terminal to the optical head drive section 62 comprising an actuator or a light emission control circuit. Here, the configurations of the control circuit 61 and the optical head driving unit 62 and the control signals transmitted and received by them vary depending on the method of recording and reproducing a plurality of types of optical disks described in the section of the prior art.

For example, when an optical system corresponding to a plurality of optical discs is provided, and the system is adapted to switch these appropriately according to the type of optical disc, the control circuit 61 transmits a control signal corresponding to the selection of the optical system to an optical system. The optical head drive unit 62 sends the data to the head drive circuit 62, and drives the optical head drive unit 62 to select an optical system corresponding to the control signal.

In the case where a light emitting element (such as a recording / reproducing laser diode) corresponding to a plurality of optical discs is provided and these are appropriately switched according to the type of the optical disc, the control circuit 61 controls the light emitting element. A control signal corresponding to the selection is transmitted to the optical head driving unit 62, and the optical head driving unit 62 is driven to select a light emitter corresponding to the control signal.

It is also possible to correspond to a large number of types of optical disks by combining a plurality of types corresponding to the above two examples. In such a case, the control circuit 61 issues a control signal. The optical head driving unit 62 may be configured to select a plurality of types of selection elements in accordance with a signal.

As shown in FIGS. 6 and 7, when the tilt angle of the recording surface can be measured, a tilt output signal corresponding to the measured tilt angle of the recording surface is sent to the control circuit 61.
The control circuit 61 converts the tilt output into an appropriate control signal, and drives an optical head driving unit including a lens skew actuator capable of changing the tilt angle of the optical head according to the control signal.

Next, with reference to FIGS. 14 to 16, a description will be given of a configuration in which a function for determining the front and back of the optical disk is provided in addition to the configuration for detecting the position of the recording surface of the optical disk. In this case, the light sensor 30 is provided with the light emitting unit 31 and the light receiving unit 32 as shown in FIG. The three photodetectors 32A arranged in the tilting direction,
The difference is that 32B and 32C are provided.

Here, when the optical disk 10 is a DVD, as shown in FIG. 14A, the light reflected by the recording surface 10a is mainly detected by the light detector 32A. When the optical disk 10 is a CD, as shown in FIG. 14B, the light reflected by the recording surface 10a is mainly detected by the light detection unit 32B. Further, when the optical disk is loaded upside down, regardless of whether the optical disk 10 is a CD or a DVD, light is emitted by ink or the like printed on the back surface 10b as shown in FIG. Since the light is reflected, the reflected light is mainly detected by the light detection unit 32C.

It is possible to determine the states of FIGS. 14A and 14B, respectively, by obtaining the above-mentioned difference output for the light detection units 32A and 32B as described above. On the other hand, in order to discriminate between (a) or (b) in FIG. 14 and (c) in FIG. 14, that is, to discriminate the front and back of the optical disc, a signal processing circuit shown in FIG. 15 is provided. In this signal processing circuit, a current-to-voltage converter 41C for converting the photocurrent of the photodetector 41C is provided in addition to the current-voltage converters 41A and 41B for converting the photocurrent of the photodetectors 32A and 32B. Then, the output of the current-voltage converter 41C and the output of the current-voltage converter 41A are input to the differential amplifier 42C, and the output of the current-voltage converter 41C and the output of the current-voltage converter 41B are input to the differential amplifier 42D. I do.

Here, a difference signal obtained by the differential amplifier 42C (corresponding to a signal corresponding to the amount of light received by subtracting the amount of light received by the light detection unit 32A from the amount of light received by the light detection unit 32C) is output to the output terminal 49C. And a difference signal obtained by the differential amplifier 42D (corresponding to a signal corresponding to the amount of light received by subtracting the amount of light received by the light detection unit 32B from the amount of light received by the light detection unit 32C) from the output terminal 49D. To get.

The output terminal 49 of the signal processing circuit shown in FIG.
The outputs of C and 49D are input to a determination circuit (not shown),
If the outputs of the output terminals 49C and 49D are both at a positive potential, it is determined that the optical disk is loaded upside down. If at least one of the output terminals 49C and 49D has a negative potential, it is determined that the optical disk is normally loaded, and the type of the optical disk is determined based on the position of the recording surface described above. This determination method will be described below.

[0079]

[Table 2]

A circuit shown in FIG. 16 can be used in place of the above signal processing circuit. This signal processing circuit connects the potential output from the light detection unit 32C and the current-voltage conversion unit 41C to the inverting input terminal of the differential amplifier 42E, and connects the output of the addition amplifier 42B to the non-inverting input terminal of the differential amplifier 42E. To output to the output terminal 49E an output signal indicating whether the light reception amount of the light detection unit 32C is larger than the sum of the light reception amounts of the light detection units 32A and 32B. I have.

In this signal processing circuit, the output terminal 49
If the output potential of E is positive, it is determined that the optical disk is loaded upside down, and if the output potential of the output terminal 49E is negative, it is determined that the optical disk is loaded normally. judge. This determination method will be described below.

[0082]

[Table 3]

As described above, in the present embodiment, not only the disc type is determined based on the reflected light from the recording surface of the optical disc, but also the reflection from the printing surface and other reflecting surfaces in addition to the recording surface. It is also possible to determine the front and back of the disc based on the light. Therefore, the discrimination of the optical disk by the optical sensor according to the present embodiment is not limited to the recording surface, and can be performed based on some other reflective surface. In addition, the present invention can be applied to a case in which a plurality of optical disks having a reflective surface dedicated to determination at different positions are distinguished from each other even if the optical disks are of the same type and the same format.

FIG. 17 shows the operation period of the optical recording medium discriminating apparatus of the present embodiment. In this figure, disc insertion, disc clamp, spindle motor operation, LD
(Laser Diode of Optical Head) The steps of light emission, focus search, focus servo, tracking servo, and seek operation indicate the operation sequence of the optical recording / reproducing apparatus when an optical disk is inserted into the optical recording / reproducing apparatus.

In this embodiment, the disc type determination based on the position of the recording surface or other reflective surface of the optical disc and the disc type determination based on the reflectance of the recording surface are performed after the disc is inserted and clamped at a fixed position. From the time
This is performed within a period immediately before the light emitting element of the optical head emits light. This eliminates the necessity of erroneously irradiating an inappropriate laser beam before discrimination.
There is no danger of accidentally damaging R or the like. In addition, since an optical sensor different from the optical head is used, it is not necessary to perform a focus search, a servo operation, and a seek operation before determining the disc type, so that the determination can be performed in a short time.

The above-described detection of the inclination angle of the recording surface may be performed over the entire surface of the optical disk during a seek operation by moving the carriage 20 shown in FIG. 1, or may be performed constantly when recording or reproducing data. As shown in FIG.
Will be implemented in the period of.

The light emitting section 31 of the optical sensor 30 constituting the discriminating apparatus according to the present embodiment is preferably constituted by an inexpensive light source having a small light output and directivity such as a light emitting diode. This is because the discriminating device does not need a large light output such as laser light or a high directivity, does not need to narrow down the light spot, and can reduce the manufacturing cost. Also, the disc type can be safely determined for an optical disc such as a CD-R that can be written only once without losing the recordability.

The optical sensor 3 of the discriminating apparatus according to the present embodiment
0 can be arranged at any position as long as it can face the recording surface or other reflection surface of the optical disk. From the viewpoint of improving the compatibility with many optical discs, the position of the optical sensor is desirably close to the center of the optical head with respect to the optical disc. If the tilt angle of the recording surface is measured and the tilting attitude of the optical head is controlled so that the optical head has a function of keeping the optical path of the optical head perpendicular to the recording surface, the optical head seeks. During operation, the optical sensor can be moved together with the optical head, and the recording surface can be configured to measure the inclination angle of the recording surface at the start of recording or reproduction, or can be configured to always observe the inclination angle of the recording surface during recording or reproduction. Therefore, the optical head is preferably mounted on a carriage 20 of the optical head as shown in FIG.

[0089]

As described above, according to the present invention, the following effects can be obtained.

According to the first or eleventh aspect, the optical recording medium can be reliably determined based on the position of the reflection surface in the thickness direction detected by the reflection surface detection means, and the reflection surface detection means can detect the optical recording medium. Since the detection is performed separately from the operation of the optical head by being provided separately from the head, the detection can be completed in a short time.

According to the second aspect, since the determination of the optical recording medium is completed before the optical head starts the operation of accessing the optical recording medium, the determined optical recording medium can be used without performing useless operations. Since the optical recording / reproducing apparatus can be operated according to the time, the initial operation of the optical recording / reproducing apparatus can be performed quickly, and the optical recording medium can be determined before the optical recording medium is irradiated with light from the optical head. CD-R
Thus, it is possible to prevent an accident of an optical recording medium that may be damaged by light irradiation.

According to the third aspect, the position of the reflecting surface in the thickness direction can be easily detected with a simple configuration by combining the light emitting section and the light receiving section.

According to the fourth aspect, the detection position or the detection range of the reflected light is detected based on the difference between the detected light amounts of the two or more light detection units, so that the detection stability against noise can be improved. False detection can be prevented.

According to the fifth aspect, the spread of the light beam emitted from the light emitting section can be limited by the light condensing means.
Detection accuracy and detection intensity can be increased.

According to the sixth aspect, the focal position of the light condensing means is set so as to be located before and after the light receiving portion depending on the type of the optical recording medium. Can be prevented.

According to the seventh aspect, the size can be reduced because of being integrated by the resin mold, and the handling such as assembly and replacement is easy.
Since the light condensing means is constituted by the resin mold itself, the number of components can be reduced, so that the manufacturing cost can be reduced.

According to the eighth or twelfth aspect, the type of the optical recording medium can be determined not only by the position of the reflection surface in the thickness direction but also by the amount of reflected light. Can be accurately determined.

According to the ninth aspect or the thirteenth aspect, since the front and back sides can be determined in addition to the type of the optical recording medium, the erroneous loading can be surely known.

According to the tenth aspect or the fourteenth aspect, it is possible to control the attitude of the optical head so as to more reliably perform the recording / reproducing operation by detecting the inclination angle of the reflection surface.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a schematic structure of an embodiment of an optical recording medium discriminating apparatus according to the present invention.

FIGS. 2A and 2B are explanatory diagrams showing a principle of determining an optical recording medium according to an embodiment of the present invention.

FIGS. 3A and 3B are explanatory diagrams illustrating a principle of determining an optical recording medium according to different embodiments. FIGS.

FIGS. 4A and 4B are explanatory diagrams showing the principle of determining an optical recording medium in still another embodiment.

FIG. 5A is a perspective view illustrating an actual configuration of an optical sensor according to an embodiment of the present invention, and FIG. 5B is a perspective view illustrating an actual configuration of an optical sensor according to another embodiment.

FIG. 6 is a perspective view showing a substantial configuration of an optical sensor in still another embodiment.

FIGS. 7A and 7B are an explanatory diagram showing the operation principle in the embodiment shown in FIG. 6 and a graph showing the relationship between the tilt of the disk and the tilt output.

FIG. 8 is a graph showing a relationship between a recording / reproducing wavelength and a reflectance of a recording surface in an optical disc.

FIG. 9 is a schematic circuit configuration diagram illustrating a configuration of a signal processing circuit according to an embodiment of the present invention.

FIG. 10 is a graph showing a relationship between a distance from a light incident surface to a recording surface of an optical disc and a difference output of a signal processing circuit.

FIG. 11 is a schematic circuit configuration diagram illustrating a configuration of a determination circuit for a difference output according to the embodiment of the present invention.

FIG. 12 is a schematic circuit configuration diagram showing a configuration of a determination circuit for a sum output of the embodiment.

FIG. 13 is a configuration block diagram illustrating a schematic configuration of an optical recording / reproducing apparatus including a disc determination unit in each embodiment.

FIGS. 14A, 14B, and 14C are explanatory diagrams illustrating a discrimination principle of an embodiment that also enables discrimination between front and back of an optical disc.

15 is a schematic circuit configuration diagram showing a configuration of a signal processing circuit in the embodiment shown in FIG.

FIG. 16 is a schematic circuit diagram showing a configuration of another signal processing circuit in the embodiment shown in FIG. 14;

FIG. 17 is a flowchart showing an initial operation flow of the optical recording / reproducing apparatus in each embodiment according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Optical disk 10a Recording surface 10b Back surface 30 Optical sensor 31 Light emitting part 32 Light receiving part 32A, 32B, 32C Light detection part

Claims (14)

[Claims] 1. A recording medium discriminating device used in an optical recording / reproducing apparatus for recording and / or reproducing data on / from an optical recording medium, comprising: a light source for recording and / or reproducing data on / from the optical recording medium. Separately from the head, a reflecting surface detecting means for optically detecting the position of the reflecting surface of the optical recording medium in the thickness direction is provided, and the light is reflected by the position of the reflecting surface detected by the reflecting surface detecting means. An optical recording medium discriminating apparatus for discriminating a recording medium. 2. The position of the reflection surface according to claim 1, wherein the position of the reflection surface is detected by the reflection surface detection means within a period from when the optical recording medium is mounted on the optical recording / reproducing apparatus to when light irradiation is performed by the optical head. And an optical recording medium discriminating apparatus configured to measure the optical recording medium. 3. The light-emitting device according to claim 1, wherein the reflection surface detecting means irradiates the optical recording medium with light, and detects light reflected from the reflection surface obtained by irradiating the light-emitting portion with light. An optical recording medium discriminating device configured to detect a position or a detection range of a light in a thickness direction of the reflection surface based on the detection position or the detection range of the reflected light. . 4. The light receiving section according to claim 3, wherein the light receiving section includes at least two light detecting sections for detecting the reflected light, and a detecting position of the reflected light based on a difference between light amounts detected by the light detecting sections. Alternatively, an optical recording medium discriminating device configured to detect a detection range. 5. The optical recording medium discriminating apparatus according to claim 3, wherein a light condensing unit for the light emitted from the light emitting unit is provided between the light emitting unit and the optical recording medium. 6. The optical recording medium according to claim 5, wherein a focal position of the light condensing unit is set closer to the optical recording medium than a light receiving position of the light receiving unit for the optical recording medium far from the reflection surface, An optical recording medium discriminating apparatus in which, for an optical recording medium close to the reflection surface, the focal position of the light condensing means is set so as to be closer to the optical recording medium than the light receiving position of the light receiving unit. . 7. The apparatus according to claim 5, wherein the light emitting unit, the light receiving unit, and the light collecting unit are integrated by a resin mold, and the light collecting unit is formed by the resin mold. 8. The optical recording medium according to claim 1, wherein the type of the optical recording medium is determined based on a position of the reflection surface in a thickness direction and a reflected light amount detected by the light receiving unit. apparatus. 9. The optical recording medium according to claim 1, wherein the type and the front and back of the optical recording medium are determined based on the position in the thickness direction of the reflection surface detected by the reflection surface detection means. Discriminator. 10. An optical recording medium discriminating apparatus according to claim 1, wherein said reflection surface detecting means detects an inclination angle of said reflection surface and detects an inclination of said reflection surface. 11. An optical recording / reproducing apparatus which performs recording and / or reproduction on an optical recording medium, an optical head for recording and / or reproducing on / from the optical recording medium, and a reflection surface of the optical recording medium. Reflective surface detecting means for optically detecting the position in the thickness direction of the optical recording medium; and determining means for determining the optical recording medium based on the position of the reflective surface detected by the reflective surface detecting means. An optical recording / reproducing apparatus configured to switch the optical head or an access method of the optical head to the optical recording medium according to a determination result of the means. 12. The optical recording / reproducing apparatus according to claim 11, wherein the discriminating means is configured to discriminate the optical recording medium based on a position of the reflecting surface and a reflected light amount detected by the reflecting surface detecting means. . 13. The optical disc drive according to claim 11, wherein the discriminating unit is configured to determine the type and the front and back of the optical recording medium based on a position in the thickness direction of the reflection surface detected by the reflection surface detection unit. Optical recording and reproducing device. 14. An optical recording / reproducing apparatus according to claim 11, wherein said reflection surface detection means detects an inclination angle of said reflection surface and drives said optical head in accordance with said inclination angle.