WO2005059907A1

WO2005059907A1 - Optical information recording/reproduction device and optical information recording/reproduction method

Info

Publication number: WO2005059907A1
Application number: PCT/JP2004/018377
Authority: WO
Inventors: Kousei Sano; Shin-Ichi Kadowaki
Original assignee: Matsushita Electric Industrial Co., Ltd.
Priority date: 2003-12-16
Filing date: 2004-12-09
Publication date: 2005-06-30

Abstract

There are provided an optical information recording/reproduction device and method capable of stably recording/reproducing information by accurately correcting the aberration of an optical disc (information storage medium) having two or more recording layers. The optical information recording/reproduction device includes: an optical head device for writing and reading a signal; a signal processing circuit for generating a signal as an index (inclination and thickness error of the protection layer, etc.) of characteristic of the optical disc; and a memory for storing the index. The index is acquired from the signal when reproducing the non-transparent layer of the optical disc and stored in memory. When recording/reproducing a translucent layer of the optical disc, the control circuit drives correction means according to the index recorded in the memory, thereby accurately correcting the aberration even in the translucent layer where an inspection error is easily caused by the recording film thickness irregularities or the like and stably performing information recording/reproduction.

Description

Specification

Optical information recording / reproducing apparatus and optical information recording / reproducing method

Technical field

The present invention relates to an optical information recording / reproducing apparatus for recording (writing) and Z or reproducing (reading) information on / from an information storage medium such as an optical disk or an optical card, and an optical information recording / reproducing method. is there.

Background art

[0002] Conventionally, for example, recording of an information signal and reproduction of an information signal recorded on the information storage medium such as an optical disk or an optical card (hereinafter simply referred to as information recording and Z or reproduction as appropriate) As an optical information recording / reproducing device capable of performing recording / reproducing, the optical beam reflected by the optical disk (information storage medium) is used to detect the characteristics of the optical disk, such as thickness error, and to detect such characteristics. A device that controls a correcting unit so as to correct generated aberration is known (for example, see Patent Document 1).

[0003] In the present specification, "recording and Z or (playback or recording / reproduction of information signal on information storage medium)" means "recording (information signal on information storage medium) and (recording information signal on information storage medium)". At least one of the reproduction of the information signal recorded in the above), which is described in a simplified manner. Therefore, "an optical information recording / reproducing apparatus or an optical information recording / reproducing method for recording and Z or reproducing (information signal on an information storage medium)"

, `` There is an optical information recording / reproducing device capable of both recording (information signal on the information storage medium) and reproducing (information signal recorded on the information storage medium)! However, the present invention also encompasses "a read-only optical information reproducing apparatus or an optical information reproducing method capable of only reproducing (information signals recorded on an information storage medium!)".

FIG. 13 is an explanatory diagram schematically showing a configuration of an aberration detecting mechanism of the conventional optical information recording / reproducing apparatus.

As shown in FIG. 13, in the conventional optical information recording / reproducing apparatus, the light beam emitted from the semiconductor laser 101 is transmitted through the half mirror 102 and then becomes parallel light by the collimator lens 103. The collimated light beam passes through the liquid crystal element (wavefront conversion element) 104 and passes through the objective lens. The light becomes convergent light at the point 105 and is focused on the information recording layer 107 of the optical disk 106. On the other hand, the light reflected by the information recording layer 107 passes through the objective lens 105 again, becomes parallel light, passes through the liquid crystal element 104 and the collimator lens 103, and is reflected by the half mirror 102. This reflected light beam is split into several light beams by the hologram element 108 and received by the photodetector 109. The photodetector 109 outputs an electric signal corresponding to the received light intensity, and inputs the signal to the aberration signal processing circuit 110. The aberration signal processing circuit 110 calculates the amount of aberration from the input signal, and outputs a drive signal required for the correction to the liquid crystal element 104.

FIG. 14 is an explanatory diagram showing an example of aberration detection using the aberration detection mechanism. As shown in this figure, the light beam 111 applied to the hologram element 108 is diffracted at different angles depending on the irradiation location. In FIG. 14, the light irradiated to the hatched area becomes a light beam 112 (see the dashed line), and the light irradiated to the inner semicircular area becomes the light beam 113 (see the dashed line). ). The light beam 112 is applied to a dividing line separating the detection area 114 and the detection area 115, and the light beam 113 is applied to a dividing line separating the detection area 116 and the detection area 117.

[0006] The cross-sectional shape of the light beam 112 and the light beam 113 changes in the front-back relationship between the focal position and the detection surface of the photodetector. When the focal point is on the near side of the detector (that is, on the hologram side), the cross-sectional shape is inverted from the cross-sectional shape on the hologram, and the light amount on the detection region 115 (or the detection region 117) side increases. On the other hand, when the focal point is farther from the detector (that is, on the opposite side of the hologram), the cross-sectional shape is similar to the cross-sectional shape on the hologram, and the light amount on the detection area 114 (or the detection area, 116) side is reduced. growing. When the focal point is on the plane of the detector, the light beam has a substantially circular shape, and the light amounts of the detection regions 114 and 115 (or the detection regions 116 and 117) are substantially equal.

[0007] Therefore, from the differential signal of the signals obtained from the detection area 114 and the detection area 115, it is possible to detect the focal position in the shaded area. Similarly, from the differential signal of the signals obtained from the detection area 116 and the detection area 117, it is possible to detect the focal position of the area inside the shaded area. As is well known, spherical aberration occurs when there is a thickness error in a transparent substrate that is a protective layer of an optical disk. When there is this spherical aberration, the inner circumference near the optical axis of the light beam and the optical axis The focal position is different from the outer peripheral portion where the force is far. A signal proportional to the spherical aberration can be obtained from the difference between the signal that detects the focal position of the hatched portion and the signal that detects the focal position of the area inside the hatched portion.

[0008] As described above, in the optical information recording / reproducing apparatus according to the above-described conventional example, the optical beam force generated by irradiating the optical disk and the spherical aberration detection signal are generated, and the liquid crystal element 104 is directly controlled. Was corrected.

In Patent Document 1, in addition to the spherical aberration, a method of detecting coma caused by the tilt (tilt) of the optical disk with respect to the optical head device, a method of detecting astigmatism generated by birefringence of the optical disk, and the like. The detection method is also disclosed.

[0009] Patent Document 2 discloses another detection method for detecting spherical aberration and comma aberration generated due to the tilt (tilt) of an optical disk.

FIG. 15 is an explanatory diagram schematically showing the configuration of the optical information recording / reproducing apparatus according to the conventional example, and explains the recording / reproducing of information on / from a two-layer disc. As shown in this figure, the optical beam emitted from the optical head device 120 is applied to the optical disk 121. The optical disc 121 has two information layers, an information layer 122 having a non-transmissive film and an information layer 123 having a semi-transmissive film. The light beam applied to the optical disc 121 is reflected by the information layer and returns to the optical head device 120 again. The returned light beam is detected by the detection unit 124.

[0010] The signal processing circuit 125 receives the signal output from the detection unit 124 and detects the amount of coma aberration. The control circuit 126 receives a signal proportional to the coma aberration and outputs a drive signal required for correction. The tilt actuator 127 receives a drive signal from the control circuit 126 and corrects coma aberration by tilting the objective lens. The optical head device 120 can also move the inner peripheral force of the optical disk 121 to an arbitrary position up to the outer periphery by the transfer mechanism 128. The optical disk 121 is rotated by a motor 129. Thus, the optical head device 120 can access an arbitrary position on the optical disk 121.

Patent Document 1: JP-A-2000-155979 (Page 13, FIG. 1, FIG. 6)

Patent Document 2: JP-A-2002-190125 (Page 17, FIG. 2, FIG. 6)

Disclosure of the invention

Problems the invention is trying to solve [0011] In the conventional configuration (see FIG. 15) for recording / reproducing information to / from a multi-layer optical disc, in a multi-layer optical disc 121 such as a two-layer disc, aberrations and the like are detected for each of the information layers 122 and 123, Had control. However, in the case of the multilayer disc 121, a semi-transparent film is formed near the light incident side and the layer 123 is required to transmit light, and the innermost layer 122 is formed. With regard to, a light-impermeable film is formed because it is not necessary to transmit light. For this reason, although the composition of each of the information layers 122 and 123 is different, in particular, the characteristics of a semi-permeable film tend to vary because the film thickness cannot be too large. Therefore, when the aberration detection is performed on the information layer 123 having the semi-transmissive film, it is difficult to perform stable aberration detection and perform accurate correction.

[0012] The present invention has been made in view of a large technical problem, and has been described in detail with respect to a multilayer disc having two or more layers having a semi-permeable film, which stably detects aberrations and the like, and corrects the aberration. It is an object of the present invention to provide an optical information recording / reproducing apparatus and an optical information recording / reproducing method capable of accurately controlling the information.

Means for solving the problem

[0013] In order to solve the above-mentioned conventional problems, an optical information recording / reproducing apparatus of the present invention provides an information signal recording and Z or reproduction on an information storage medium capable of recording and / or reproducing information signals by light. An optical head device, a signal processing circuit that outputs an index indicating characteristics of the information storage medium, a storage unit that stores the index, a correction unit that corrects aberration based on the index, and the correction unit The information storage medium has at least two or more information layers, and an index obtained when the optical head device records or reproduces a specific layer among the information layers. Is stored in the storage means, and when the optical head device records or reproduces a layer other than the specific layer, an index for the specific layer stored in the storage means is indicated. And controlling the correction means using It is a sign.

With this configuration, aberrations can be accurately corrected even in an information storage medium having two or more layers.

Further, the optical information recording / reproducing apparatus of the present invention has means for detecting a positional relationship between the optical head device and the information storage medium, and the optical head device also records the specific layer. Alternatively, the index obtained at the time of reproduction is stored in the storage means in association with the positional relationship, and when the optical head device records or reproduces a layer other than the specific layer, the index is stored in the storage means. Preferably, the correction means is controlled using a value related to the positional relationship among the indices.

According to this configuration, aberration can be accurately corrected even if the characteristics of the information storage medium change depending on the location in the information storage medium having two or more layers.

[0015] In the optical information recording / reproducing apparatus of the present invention, one of the two or more information layers is a non-transmissive layer that does not transmit light, and the other information layer is a semi-transmissive layer that transmits some light. And the specific layer may be a non-transmissive layer.

In this case, accurate aberration correction can be performed in an information storage medium having two or more layers having a non-transmissive layer and a semi-transmissive layer.

[0016] In the optical information recording / reproducing apparatus of the present invention, the index may indicate an inclination of the information storage medium.

In this case, the inclination of the information storage medium having two or more layers can be accurately corrected.

[0017] It is preferable that the correcting means of the optical information recording / reproducing apparatus of the present invention corrects coma.

According to this configuration, it is possible to accurately correct coma caused by the inclination of the information storage medium having two or more layers.

In the optical information recording / reproducing apparatus according to the present invention, the index may indicate a thickness error of a protective layer of the information storage medium.

In this case, it is possible to accurately correct the thickness error of the protective layer of the two or more information storage media.

It is preferable that the correcting means of the optical information recording / reproducing apparatus of the present invention corrects spherical aberration.

According to this configuration, it is possible to accurately correct spherical aberration caused by a thickness error of the protective layer of the two or more information storage media.

In the optical information recording / reproducing apparatus according to the present invention, the index may indicate a birefringence of the information storage medium. In this case, the birefringence of the information storage medium having two or more layers can be accurately corrected.

Further, it is preferable that the correcting means of the optical information recording / reproducing apparatus of the present invention corrects astigmatism.

According to this configuration, astigmatism generated by birefringence of the information storage medium having two or more layers can be accurately corrected.

In the optical information recording / reproducing apparatus of the present invention, it is preferable to use address information for detecting the positional relationship.

According to this configuration, the positional relationship can be reliably detected.

In the optical information recording / reproducing apparatus of the present invention, it is more preferable that the information storage medium has a disk shape, and the positional relationship indicates a radial position of the information storage medium. According to this configuration, the characteristic of the disc-shaped information storage medium that changes in the radial direction can be accurately corrected.

[0024] In the optical information recording / reproducing apparatus of the present invention, the information storage medium may have a disk shape, and the positional relationship may indicate an angular position of the information storage medium in a rotation direction.

In this case, the characteristics of the disc-shaped information storage medium that changes in the rotation direction can be accurately corrected.

In the optical information recording / reproducing apparatus of the present invention, the index is stored in the storage means over the entire surface of the information storage medium, and thereafter, the optical head device records or reproduces a layer other than a specific layer. At this time, it is possible to control the correction means using the index stored in the storage means.

According to this configuration, since all indices are captured first, subsequent recording and playback can be performed smoothly.

[0026] In the optical information recording / reproducing device of the present invention, when the optical head device records or reproduces a layer other than the specific layer, the optical recording device reproduces the specific layer as needed to read the information storage medium. The index can be stored in a storage unit, and when the optical head device records or reproduces a layer other than the specific layer, the correction unit can be controlled using the index stored in the storage unit. According to this configuration, the start-up is quick because much time is not taken for the first acquisition.

[0027] Further, the optical information recording / reproducing apparatus of the present invention may be a reproduction-only apparatus including an optical head device that performs only reproduction of information on an information storage medium.

In this case, in a reproduction-only medium, the difference can be accurately corrected even with an information storage medium having two or more layers.

[0028] Further, the optical information recording / reproducing method of the present invention can record and Z or reproduce information by light, and can record and Z or reproduce information on an information storage medium having at least two or more information layers. An optical information recording / reproducing method for recording and / or reproducing information on / from the information storage medium using an optical head device for recording / reproducing a specific layer among the information layers. Obtaining an index indicating the characteristics of the information storage medium; storing the index in a storage unit for storing the index; and storing the index when the optical head device records or reproduces a layer other than the specific layer. Controlling the correction means using the indices stored in the means to correct aberrations.

With this method, aberrations can be accurately corrected even for information storage media with two or more layers.

[0029] In the optical information recording / reproducing method of the present invention, when the optical head device stores in a storage means an index obtained when recording or reproducing the specific layer, the optical head device and the optical head device are used to store the index. When the optical head device records or reproduces a layer other than the specific layer, a value related to the positional relationship among the indices stored in the storage means is recorded in association with the positional relationship with the information storage medium. It is preferable to control the correction means by using.

According to this method, aberration can be accurately corrected even if the characteristics of the information storage medium change depending on the location in the information storage medium having two or more layers.

[0030] In the optical information recording / reproducing method of the present invention, one of the two or more information layers is a non-transmission layer that does not transmit light, and the other information layer is a semi-transmission layer that transmits some light. And the specific layer may be a non-transmissive layer.

In this case, the information storage medium having two or more layers having a non-transmissive layer and a semi-transmissive layer It is possible to perform accurate aberration correction.

In the optical information recording / reproducing method according to the present invention, the index may indicate an inclination of the information storage medium.

[0032] Further, in the optical information recording / reproducing method of the present invention, it is preferable that the correction means corrects coma.

According to this method, it is possible to accurately correct coma caused by the inclination of the information storage medium having two or more layers.

[0033] In the optical information recording / reproducing method of the present invention, the index may indicate a thickness error of a protective layer of the information storage medium.

[0034] In the optical information recording / reproducing method of the present invention, it is preferable that the correcting means corrects spherical aberration.

According to this method, it is possible to accurately correct a spherical aberration caused by a thickness error of a protective layer of two or more information storage media.

[0035] In the optical information recording / reproducing method of the present invention, the index may indicate a birefringence amount of the information storage medium.

In this case, the birefringence of the information storage medium having two or more layers can be accurately corrected.

[0036] In the optical information recording / reproducing method of the present invention, it is preferable that the correcting means corrects astigmatism.

According to this method, astigmatism generated by birefringence of an information storage medium having two or more layers can be accurately corrected.

In the optical information recording / reproducing method of the present invention, it is preferable to use address information for detecting the positional relationship.

According to this method, the positional relationship can be reliably detected.

In the optical information recording / reproducing method according to the present invention, it is preferable that the information storage medium has a disk shape, and the positional relationship indicates a radial position of the information storage medium. According to this method, the characteristics of the disc-shaped information storage medium that changes in the radial direction can be accurately corrected.

In the optical information recording / reproducing method according to the present invention, the information storage medium may have a disk shape, and the positional relationship may indicate an angular position of the information storage medium in a rotation direction.

[0040] In the optical information recording / reproducing method of the present invention, the index is stored in the storage means over the entire surface of the information storage medium, and when the optical head device records or reproduces a layer other than the specific layer thereafter. Then, the correction means can be controlled using the index stored in the storage means.

According to this method, all indexes are first captured, so that subsequent recording and playback can be performed smoothly.

[0041] In the optical information recording / reproducing method of the present invention, when the optical head device records or reproduces a layer other than the specific layer, the optical recording device reproduces the specific layer as necessary to read the information storage medium. The index is stored in the storage means, and when the optical head device records or reproduces a layer other than the specific layer, the correction means can be controlled using the index stored in the storage means.

According to this method, the startup is quicker because the initial acquisition is less time-consuming.

[0042] Further, the optical information recording / reproducing method of the present invention can be applied to reproduction-only operation of reproducing information only from an information storage medium.

According to this method, in the case of reproduction only, aberration can be accurately corrected even in an information storage medium having two or more layers.

The invention's effect

According to the present invention, even in an information recording medium having a semi-transmissive layer such as a two-layer disc, the error can be corrected stably, and the recording and z or reproduction of the information signal can be reliably performed. In addition, according to the present invention, since the initial loading is not time-consuming, the startup is quick. The

Brief Description of Drawings

FIG. 1 is an explanatory view schematically showing a configuration of an optical information recording / reproducing apparatus according to Embodiment 1 of the present invention.

FIG. 2 is a configuration diagram of the optical information recording / reproducing apparatus for explaining recording / reproduction on a semi-transmissive layer of an optical disc.

FIG. 3 is a flowchart for explaining coma aberration correction control by the optical information recording / reproducing apparatus.

FIG. 4 is an explanatory diagram showing an example of a table of information stored in a memory of the optical information recording / reproducing device.

FIG. 5 is an explanatory view schematically showing a configuration of an optical information recording / reproducing apparatus according to Embodiment 2 of the present invention.

FIG. 6 is a configuration diagram of an optical information recording / reproducing apparatus according to a second embodiment for explaining recording / reproduction on a semi-transmissive layer of an optical disc.

FIG. 7 is a flowchart for explaining thickness error correction control by the optical information recording / reproducing apparatus of Embodiment 2.

FIG. 8 is an explanatory diagram showing an example of a table of information stored in a memory according to the second embodiment.

FIG. 9 is an explanatory view schematically showing a configuration of an optical information recording / reproducing apparatus according to Embodiment 3 of the present invention.

FIG. 10 is a configuration diagram of an optical information recording / reproducing apparatus according to a third embodiment for explaining recording / reproduction on a semi-transmissive layer of an optical disc.

FIG. 11 is an explanatory diagram showing an example of a table of information stored in a memory according to the third embodiment.

FIG. 12 is an explanatory sectional view of an optical disc showing another example of the optical disc (information storage medium) according to the embodiment of the present invention.

FIG. 13 is an explanatory diagram schematically showing a configuration of an aberration detection mechanism of a conventional optical information recording / reproducing device.

FIG. 14 is an explanatory diagram showing an example of aberration detection by the aberration detection mechanism.

[FIG. 15] An optical information recording / reproducing apparatus according to another conventional example, which records information on a double-layer disc. FIG. 2 is an explanatory diagram schematically showing a configuration of a device for performing reproduction.

Explanation of symbols

[0045] 1, 51 optical disk (information storage medium)

2, 52 Non-transmissive layer

3, 53, 54 translucent layer

7 Tilt actuator (correction means)

8 Transfer mechanism

9 motor

10, 31, 41 Optical head device

14, 33, 43 detector

21, 34, 44 signal processing circuit

22 Head position detector

23, 36, 47 memory (storage means)

24, 37, 48 control circuit

32 beam expander (correction means)

35 Address analysis circuit

42 Liquid crystal element (correction means)

45 Motor with encoder

46 Encoder reading device

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

(Embodiment 1)

FIG. 1 is an explanatory diagram schematically showing a configuration of an optical information recording / reproducing apparatus according to Embodiment 1 of the present invention.

First, as an index of the characteristics of the optical disk (information storage medium), the inclination of the disk is detected using a signal from the non-transmissive layer and stored in a memory (storage means). An example in which the tilt actuator (correction means) is controlled using information from the memory will be described. In FIG. 1, in the optical head device 10, focus control is applied to the non-transmissive layer 2 of the optical disc (information storage medium) 1. The light reflected by the non-transmissive layer 2 returns to the optical head device 10 and is converted into an electric signal by the detection unit 14. The signal processing circuit 21 receives the signal from the detection unit 14, detects the coma aberration, and outputs a signal (tilt signal) proportional to the amount of tilt of the optical disc 1 with respect to the optical head device 10.

The head position detecting means 22 detects the position of the optical head device 10 in the radial direction with respect to the optical disk 1, and outputs this detection signal as head position information. The memory (storage means) 23 receives the signals from the signal processing circuit 21 and the head position detecting device 22 and correlates these signals. .

[0048] The control circuit 24 outputs a signal for driving the tilt actuator (correction means) 7, and during this time, outputs a control signal for controlling the tilt actuator to maintain a constant attitude. .

The optical head device 10 can be moved in the radial direction of the optical disc 1 by the transfer mechanism 8. When the optical disk 1 is loaded, the transfer mechanism 8 moves the optical head device 10 from the inner circumference to the outer circumference of the disk 1, and at each point where the radial direction of the disk 1 is divided into, for example, 10, the head position and the optical data are read. The amount of tilt of the disk is recorded in the memory.

[0049] Although not specifically shown, the optical information recording / reproducing apparatus more preferably includes, for example, a controller mainly including a microcomputer in order to control the operation of the entire apparatus. (Equipment controller) is provided, and all the components such as the tilt actuator 7, the transfer mechanism 8, the motor 9, the optical head device 10, the signal processing circuit 21, the memory 23, and the control circuit 24 are all provided. Are connected to the device controller so as to be able to send and receive signals. In the optical information recording / reproducing apparatus shown in FIG. 1, the optical disk 1, the tilt actuator 7, the transfer mechanism 8, the motor 9, and the optical head device 10 are the optical disk 121, the tilt actuator shown in FIG. The writer 127, the transfer mechanism 128, the motor 129, and the optical head device 120 basically have the same configuration and perform the same operation.

FIG. 2 is a configuration diagram of the optical information recording / reproducing apparatus for explaining recording / reproducing on the semi-transmissive layer of the optical disc 1.

In the optical head device 10, focus control is applied to the semi-transmissive layer 3 of the optical disc 1. The head position detection device 22 detects a position in the radial direction with respect to the optical disc 1, and outputs this detection signal as head position information. When receiving the signal from the head position detecting device 22, the memory 23 outputs a tilt signal indicating a tilt amount corresponding to the head position based on the related information stored in advance. Then, the control circuit 24 generates a drive signal based on the tilt signal, and drives the tilt actuator 7. As a result, the objective lens is tilted according to the tilt amount of the optical disk, and the coma aberration is corrected.

If the information on the position just corresponding to the detection signal from the head position detecting device 22 is not present in the memory 23, the inclination amount supplemented based on the information on the inclination amount of a position near the position is stored. Is generated and a tilt signal is output. As this interpolation method, for example, the inclination amount data at the two closest points across the position is extracted, and a proportional operation is performed based on each inclination amount data and each distance from the position to the two points. Various known interpolation techniques such as a method for performing the interpolation can be applied.

The flowchart of FIG. 3 explains the coma aberration correction control.

The control starts when the optical disk is newly loaded or when the power of the optical information recording / reproducing device is turned on. First, in step S1, focus control is applied to the non-transmissive layer 2 (see FIG. 1). Next, in step S2, by moving the position of the optical head 10 by driving the transfer mechanism 8, the optical head 10 scans the entire surface of the optical disc 1, and a signal (tilt) proportional to the amount of tilt at each position. Signal) and the position of the optical head 10 are recorded in the memory 23 in association with each other.

Thereafter, in step S3, the semi-transmissive layer 3 is subjected to focus control (see FIG. 2). Then, in step S4, the tilt amount is output to the control circuit 24 based on the position information of the optical head 10 from the head position detecting device 22 and the information recorded in the memory 23, and in step S5, the control circuit 24 drives the tilt actuator 7 to correct coma. The above correction control is more preferably performed by the above-described device controller (not shown).

FIG. 4 shows an example of a table of information stored in the memory 23. As shown in this figure, at each address (memory address) of the memory 23, a radial position and a tilt amount of the disk 1 at this position are stored in association with each other.

Conventionally, a signal obtained by irradiating the semi-transmissive layer 3 with a light beam is used even in the semi-transmissive layer 3. Aberration correction. However, as is well known, it is difficult to form a uniform and stable film over the entire surface of the information storage medium, which is difficult to form. In particular, when detecting the aberration and the like by dividing the far field of the light beam, the light amount becomes uneven due to the portion in the far field. If there is such uneven light amount, an error occurs in the original aberration detection. Therefore, it has been difficult to accurately correct aberration.

According to the configuration of the present embodiment, when recording / reproducing information to / from the semi-transmissive layer 3, the amount of inclination (index) of the optical disc 1 detected by the non-transmissive layer 2 is used, whereby the semi-transmissive layer 3 is used. The error in detecting the amount of tilt due to the variation in the film of No. 3 is eliminated, the amount of tilt of the optical disc 1 can be accurately corrected, and the information signal can be stably recorded and reproduced on the semi-transmissive layer 3 as well. .

Further, according to the configuration of the present embodiment, when information is recorded and reproduced on the semi-transmissive layer 3, the tilt amount (index) of the optical disc 1 detected by the non-transmissive layer 2 is used. It is possible to save time when detecting the amount of inclination of the semi-transmissive layer 3. As a result, the initial learning time required to start playing or recording on the optical disk can be reduced to about half. As a result, it is possible to reduce the waiting time from the insertion of the disc to the start of reproduction or recording, and to reduce the possibility of missing important scenes.

In the present embodiment, the position detecting means 22 is provided as a method of obtaining the radial position. However, when a so-called stepping motor is used as the motor for driving the transfer mechanism 8 instead, The radial position may be obtained based on the number of driving steps of the motor. In this case, first, the origin may be determined by pressing the optical head 14 against a stopper or the like, and the relationship between the number of steps and the radial position may be calibrated. By employing a powerful configuration, it is not necessary to separately provide the position detecting means 22, and it is possible to contribute to a reduction in manufacturing cost of the apparatus.

Further, in the present embodiment, the index is stored in the memory in association with the position. If the correction can be performed with one index over the entire disk, the index value detected at the initial position is stored in the disk. You may use it over the whole surface. In this case, it is not necessary to associate the index value with the position, so that the memory area can be saved.

(Embodiment 2)

FIG. 5 schematically shows a configuration of an optical information recording / reproducing apparatus according to Embodiment 2 of the present invention. FIG. In FIG. 5, components having the same configuration as in FIG. 1 and performing the same operations are denoted by the same reference numerals, and further description will be omitted.

In the second embodiment, the thickness of the protective layer of the disk is detected as an index of the characteristics of the optical disk (information storage medium) by using a signal from the non-transmissive layer, stored in the memory (storage means), and stored in the memory (storage means). The following describes an example of controlling the beam expander (correction means) using information from the memory during recording and reproduction.

As shown in FIG. 5, in the present embodiment, the optical head device 31 has a beam expander (correction means) 32 composed of two lenses, and changes the distance between the two lenses to change the light. The spherical aberration caused by the thickness error of the protective layer of the disk 1 is corrected. In FIG. 5, in the optical head device 31, focus control is applied to the non-transmissive layer 2 of the optical disc (information storage medium) 1. The light beam emitted from the optical head 31 is reflected by the non-transmissive layer 2 of the optical disc 1, and the reflected light returns to the optical head device 31 and is converted into an electric signal by the detection unit 33. The signal processing circuit 34 outputs a signal proportional to the thickness error of the protective layer (that is, the amount of spherical aberration) based on the signal obtained from the detection unit 33.

The address analysis circuit 35 receives a signal from the detection unit 33, analyzes an address recorded on the optical disc 1, and outputs an address value. The memory (storage means) 36 receives the signals from the signal processing circuit 34 and the address analysis circuit 35 and stores them in association with each other. The control circuit 37 outputs a signal for driving the beam expander (correction means) 32. During this time, the control circuit 37 outputs a control signal for controlling the beam expander to be at a fixed position. More preferably, also in the second embodiment, an apparatus controller (not shown) is provided as in the case of the first embodiment.

FIG. 6 is a configuration diagram of the optical information recording / reproducing device for explaining recording / reproducing on the semi-transmissive layer of the optical disc 1.

In the optical head device 10, focus control is applied to the semi-transmissive layer 3 of the optical disc 1. The address analysis circuit 35 receives the signal from the detection unit 33, analyzes the address recorded on the optical disc 1, and outputs an address value. The memory 36 receives the signal of the address analysis circuit 35, and based on the related information stored in advance, the optical disk 1 and the optical head device 3 A thickness error signal corresponding to the position of 1 is output.

The control circuit 37 generates a drive signal based on the signal of the thickness error, and drives the beam expander 32. As a result, the beam expander 32 is driven according to the thickness error of the protective layer of the optical disc 1, and the spherical aberration is corrected.

If there is no information on the position corresponding to the signal of the address analysis circuit 35 in the memory 23, for example, the same method as in the first embodiment, the nearest two points across the address are used. Based on the thickness error data at the address, a known interpolation method is applied to generate an interpolated thickness error at the address, and output a signal.

The flowchart in FIG. 7 explains the thickness error correction control.

The control starts when the optical disc 1 is newly loaded or when the power of the optical information recording / reproducing apparatus is turned on. First, in step S11, is there any necessary correction information for a required target position? It is determined whether or not. In the case of this determination result power O (when there is no necessary information), the non-transmissive layer 2 is focused in step S12. Next, while scanning the disk 1 for a certain period of time, the thickness error signal and the address value obtained based on the signal returned from the non-transmissive layer are stored in the memory 36 (step S13). In this way, data is taken into the memory 36 as necessary.

On the other hand, when the result of the determination in step SI 1 is YES (when there is necessary information), the semi-transparent layer is focused in step S 14. Next, in step S15, a thickness error signal is output to the control circuit 37 for the address value and the information capacity in the memory 36.

Then, the control circuit 37 outputs a drive signal to control the beam expander 32 (correction means) to a position corrected in consideration of the thickness between the semi-transmissive layer 3 and the non-transmissive layer 2, and reduces the spherical aberration. Correct (step S16).

Thereafter, in step S17, it is determined whether or not the optical head device 31 has moved to a new location on the optical disk 1 within a predetermined time set in advance, and if this determination result is YES (moving In this case, the process returns to step S11, and thereafter, a similar series of steps is repeated. On the other hand, if the decision result in the step S17 is NO, the necessary moving operation of the optical head device 31 has been completed (that is, the necessary recording and reproduction of the semi-transmissive layer 3 has been completed), and thus the control ends. It has become. The above-described correction control is more preferably performed by the above-described device control. Controller (not shown).

FIG. 8 shows an example of a table of information stored in the memory 36. As shown in this figure, at each address (memory address) of the memory 36, an address value of the non-transmissive layer 2 of the optical disc 1, a corresponding address value of the semi-transmissive layer 3, and a thickness error amount of the protective layer are shown. Stored in association. The relationship between the address value of the semi-transmissive layer 3 and the address value of the non-transmissive layer 2 is calculated by a predetermined mathematical formula.

As described above, according to the configuration of the second embodiment, when information is recorded and reproduced on the semi-transmissive layer 3 of the optical disc 1, the protection layer of the optical disc 1 detected by the non-transmissive layer 2 By using the thickness error (index), it is possible to eliminate the detection error of the thickness error amount due to the variation of the film of the semi-transmissive layer 3, and to correct the thickness error of the optical disc 1 accurately. The information can also be recorded and reproduced stably on 3.

Further, according to the configuration of the present embodiment, when recording and reproducing information on the semi-transmissive layer 3, the thickness error (index) of the protective layer of the optical disc 1 detected by the non-transmissive layer 2 is used. This can save time when detecting a thickness error for the semi-transmissive layer 3. As a result, the initial learning time required for starting reproduction or recording of the optical disk can be reduced to about half. As a result, the waiting time from when the disc is inserted to when the reproduction or recording is started can be shortened, and the possibility of missing important scenes can be reduced.

As described above, by using the address value recorded on the optical disc 1 as the information indicating the positional relationship, the positional relationship can be reliably and accurately identified, and a special position sensor is not required. This is advantageous in terms of cost.

In this embodiment, the method of using the address as a method of obtaining the radial position has been described. However, as described in the first embodiment, the position detecting means is used, or the number of driving steps of the stepping motor is used. You can do it.

(Embodiment 3)

FIG. 9 is an explanatory diagram schematically showing a configuration of an optical information recording / reproducing apparatus according to Embodiment 3 of the present invention. In FIG. 9, components having the same configuration as in FIG. 1 and performing the same operations are denoted by the same reference numerals, and further description will be omitted. In the second embodiment, the birefringence of the disc is detected using a signal from the non-transmissive layer as an index of the characteristics of the optical disc (information storage medium), stored in the memory (storage means), and recorded on the semi-transmissive layer. · An example of controlling the liquid crystal element (correction means) using information from the memory during reproduction will be described.

As shown in FIG. 9, in the present embodiment, the optical head device 41 has a correction unit including a liquid crystal element 42, and corrects astigmatism. In FIG. 9, in the optical head device 41, the focus control is applied to the non-transmissive layer 2 (not shown in FIG. 9) of the optical disk (information storage medium) 1. The light beam emitted from the optical head 41 is reflected by the non-transmissive layer 2 of the optical disc 1, and the reflected light returns to the optical head device 41 and is converted into an electric signal by the detection unit 43. The signal processing circuit 44 outputs a signal proportional to the amount of astigmatism due to birefringence of the optical disc 1 based on the signal obtained from the detection unit 43.

On the other hand, the motor 45 for rotating the optical disc 1 is provided with an encoder, and the encoder reader 46 reads the angular position of the optical disc 1 in the rotation direction. The memory (storage means) 47 receives the signals from the signal processing circuit 44 and the encoder reading device 46 and stores them in association with each other. The control circuit 48 outputs a signal for driving the liquid crystal element 42. During this time, the control circuit 48 outputs a control signal for controlling the correction amount of the liquid crystal element 42 to be constant.

More preferably, also in the third embodiment, an apparatus controller (not shown) is provided as in the first and second embodiments.

FIG. 10 is a configuration diagram of the optical information recording / reproducing apparatus for explaining recording / reproducing on the semi-transmissive layer of the optical disc 1.

In the optical head device 10, force control is applied to the semi-transmissive layer 3 (not shown in FIG. 10) of the optical disc 1. The encoder reading device 46 reads the encoder of the motor 45 with the encoder, and outputs an angular position signal of the optical disc 1. The memory 47 receives the signal of the encoder reading device 46 and, based on the related information stored in advance, generates a signal proportional to the amount of astigmatism corresponding to the angular position of the optical disc 1 and the optical head device 41. Output.

The control circuit 48 generates a drive signal based on the signal of the astigmatism amount, and controls the liquid crystal element 42 Drive. As a result, the liquid crystal element 42 is driven according to the birefringence of the optical disc 1, and astigmatism is corrected.

If there is no information on the position corresponding to the signal of the encoder reading device 46 in the memory 47, for example, in the same manner as in the first embodiment, the nearest two points across the position are used. Based on the astigmatism data at the position, a conventionally known interpolation method is applied to generate and output the interpolated astigmatism at the position.

FIG. 11 shows an example of a table of information stored in the memory 47. As shown in this figure, at each address (memory address) of the memory 47, the angular position of the optical disc 1 and the corresponding amount of astigmatism are stored in association with each other.

According to the configuration, when information is recorded on or reproduced from the semi-transmissive layer 3, the birefringence (index) of the optical disc detected by the non-transmissive layer 2 is used, so that the semi-transmissive layer 3 The detection error of the amount of birefringence due to the variation of the film of the optical disc 1 can be eliminated, the astigmatism due to the birefringence of the optical disc 1 can be corrected accurately, and the information can be stably recorded on the semi-transmissive layer 3. 'You can play it.

Further, according to the configuration of the present embodiment, when recording and reproducing information on the semi-transmissive layer 3, the birefringence amount (index) of the optical disc 1 detected by the non-transmissive layer 2 is used. In addition, it is possible to save time when detecting the amount of birefringence of the transflective layer 3. As a result, the initial learning time required to start reproduction or recording of the optical disk can be reduced to about half. As a result, the waiting time from when the disc is inserted to when reproduction or recording is started can be reduced, and the possibility of missing important scenes can be reduced.

In each of the embodiments described above, when correcting the characteristics of the non-transmissive layer 2, the characteristics of the non-transmissive layer 2 described in detail are stored in the memory. The correction may be performed using the index value, or may be corrected using the index value detected in real time.

Further, in the three embodiments described above, the optical disc (information storage medium) has an example in which it has two layers. The present invention is not limited to this. For example, as shown in FIG. The same applies to an optical disc 51 having three layers. In this case, the index value of the optical disc 51 is detected by the non-transmissive layer 52 and stored in the memory, and the semi-transmissive layer 53 is detected. When recording or reproducing information on or in the semi-transmissive layer 54, the correction means may be controlled using the information stored in the memory. In such a case, the same effects as those in the above embodiments can be obtained.

Further, the present invention can be similarly applied to the case where the number of layers is four, five, or more, and the effects of stable recording and reproduction and shortening of the rise time can be obtained. .

Further, in all of the above-described embodiments, a value serving as an index of the optical disc is detected in the non-transmissive layer and stored in the memory. Instead of using the stored information to control the correction means, instead of detecting the index value of the optical disc in the semi-transmissive layer and storing it in the memory, the non-transmissive layer On the other hand, when recording and reproducing the information signal, the correction means may be controlled using the information stored in the memory.

For example, when learning is performed by detecting the thickness error of the disk base material, the thickness of the protective layer alone can be measured by detecting with the semi-transmissive layer on the side closer to the detection system, but not on the side farther from the detection system. If detection is performed using the transmission layer, the sum of the thicknesses of the protective layer and the intermediate layer is measured, and an extra error is added. Therefore, when measuring only the thickness of the protective layer, it is more preferable to perform the learning by detecting in the semi-transmissive layer closer to the detection system.

Further, in each of the embodiments described above, the disc-shaped optical disc 1 has been described. However, the present invention is not limited to a powerful case. For example, a rectangular information storage medium such as an optical card However, the present invention can be similarly applied to a recording medium having two or more recording layers, and can achieve the same effect.

Further, in the above-described embodiment, examples of indices indicating the characteristics of the information storage medium include examples of coma due to tilt, spherical aberration due to a thickness error of the protective layer, and astigmatism due to birefringence. Increased force Similar effects can be obtained for other characteristics and aberrations. Also, regarding the method of detecting aberration and the method of correcting means, various known methods can be applied, which are not limited to the examples described in the above embodiments.

[0085] Furthermore, the present invention is applicable not only to an optical information recording / reproducing apparatus for recording and reproducing an information signal on and from an optical disc, but also to a reproduction-only apparatus or a recording-only apparatus. It can be applied effectively.

As described above, it is needless to say that the present invention is not limited to the above-described embodiment, but can be variously modified or improved without departing from the scope of the invention. Industrial applicability

The optical information recording / reproducing device according to the present invention has a function of recording and Z or reproducing information on an information storage medium, and is useful as a recording and Z or reproducing device for video and music. Further, the present invention can be applied to storage of computer data and programs, or storage of map data for car navigation.

Claims

The scope of the claims

[1] An optical head device for recording and / or reproducing information on / from an information storage medium capable of recording and / or reproducing information by light, and a signal processing for outputting an index indicating characteristics of the information storage medium A circuit, storage means for storing the index, correction means for correcting aberrations based on the index, and a control circuit for controlling the correction means,

The information storage medium has at least two or more information layers,

An index obtained when the optical head device records or reproduces a specific layer among the information layers is stored in the storage means, and when the optical head device records or reproduces a layer other than the specific layer. Controlling the correction means using the index of the specific layer stored in the storage means.

An optical information recording / reproducing apparatus characterized by the above-mentioned.

[2] means for detecting a positional relationship between the optical head device and the information storage medium, and associating an index obtained when the optical head device records or reproduces the specific layer with the positional relationship. Stored in the storage means,

When the optical head device records or reproduces a layer other than the specific layer, the optical head device controls the correction means using a value related to the positional relationship among indices stored in the storage means.

2. The optical information recording / reproducing apparatus according to claim 1, wherein:

[3] One of the two or more information layers is a non-transmission layer that does not transmit light, the other information layer is a semi-transmission layer that transmits some light, and the specific layer is a non-transmission layer. The optical information recording / reproducing device according to claim 1 or 2, wherein

4. The optical information recording / reproducing apparatus according to claim 13, wherein the index indicates a tilt of the information storage medium.

5. The optical information recording / reproducing apparatus according to claim 4, wherein the correction unit corrects coma aberration.

6. The index according to claim 11, wherein the index indicates a thickness error of a protective layer of the information storage medium.

4. The optical information recording / reproducing apparatus according to any one of 3.

7. The optical information recording according to claim 6, wherein the correction unit corrects spherical aberration. Playback device.

8. The optical information recording / reproducing apparatus according to claim 13, wherein the index indicates an amount of birefringence of the information storage medium.

9. The optical information recording / reproducing apparatus according to claim 8, wherein the correction unit corrects astigmatism.

10. The optical information recording / reproducing apparatus according to claim 2, wherein the positional relationship is detected by using address information recorded on the information storage medium.

11. The optical information recording / reproducing apparatus according to claim 2, wherein the information storage medium has a disk shape, and the positional relationship indicates a position of the information storage medium in a radial direction.

12. The optical information recording / reproducing apparatus according to claim 2, wherein the information storage medium has a disk shape, and the positional relationship indicates an angular position of the information storage medium in a rotation direction.

[13] The index is stored in the storage means over the entire surface of the information storage medium, and thereafter, when the optical head device records or reproduces a layer other than the specific layer, the index is stored in the storage means. 3. The optical information recording / reproducing apparatus according to claim 1, wherein the correction unit is controlled using an index.

[14] When the optical head device records or reproduces a layer other than the specific layer, the optical head device reproduces the specific layer as necessary and stores an index of the information storage medium in the storage means. The method according to claim 1, wherein the head device controls the correction unit using an index stored in the storage unit when recording or reproducing a layer other than the specific layer. 4. Optical information recording / reproducing device.

[15] The optical information recording / reproducing apparatus according to any one of [11] to [14], wherein the optical information recording / reproducing apparatus is a reproduction-only apparatus including an optical head device for performing only information reproduction on the information storage medium.

[16] An optical information recording and reproducing method for recording and Z or reproducing information on and from an information storage medium having at least two or more information layers, capable of recording and Z or reproducing information by light, Using an optical head device for recording and z or reproducing information on the information storage medium

Obtaining an index indicating the characteristics of the information storage medium when recording or reproducing a specific layer of the information layers;

Storing the index in storage means for storing the index;

When the optical head device records or reproduces a layer other than the specific layer, the optical head device controls a correction unit using an index stored in the storage unit to correct the aberration. Optical information recording and reproducing method.

[17] When storing in the storage means an index obtained when the optical head device records or reproduces the specific layer, the index is associated with the positional relationship between the optical head device and the information storage medium. Do

When the optical head device records or reproduces a layer other than the specific layer, the optical head device controls the correction means using a value related to the positional relationship among the indexes stored in the storage unit. 17. The optical information recording / reproducing method according to claim 16, wherein:

[18] One of the two or more information layers is a non-transmission layer that does not transmit light, the other information layer is a semi-transmission layer that transmits some light, and the specific layer is a non-transmission layer. 18. The optical information recording / reproducing method according to claim 16, wherein:

[19] The optical information recording / reproducing method according to any one of claims 16 to 18, wherein the index indicates an inclination of the information storage medium.

20. The optical information recording / reproducing method according to claim 19, wherein said correction means corrects coma aberration.

21. The optical information recording / reproducing method according to claim 16, wherein the index indicates a thickness error of a protective layer of the information storage medium.

22. The optical information recording / reproducing method according to claim 21, wherein said correcting means corrects spherical aberration.

23. The optical information recording / reproducing method according to claim 16, wherein the index indicates an amount of birefringence of the information storage medium.

24. The optical information recording / reproducing method according to claim 23, wherein the correction unit corrects astigmatism.

25. The optical information recording / reproducing method according to claim 16, wherein the positional relationship is detected by using address information recorded on the information storage medium.

26. The optical information recording / reproducing method according to claim 17, wherein the information storage medium has a disk shape, and the positional relationship indicates a position of the information storage medium in a radial direction.

27. The optical information recording / reproducing method according to claim 17, wherein the information storage medium has a disk shape, and the positional relationship indicates an angular position in a rotation direction of the information storage medium.

[28] The index is stored in the storage means over the entire surface of the information storage medium, and thereafter, when the optical head device records or reproduces a layer other than the specific layer, the index is stored in the storage means. 19. The optical information recording / reproducing method according to claim 16, wherein the correction means is controlled using an index.

[29] When the optical head device records or reproduces a layer other than the specific layer, the optical head device reproduces the specific layer as necessary and stores an index of the information storage medium in the storage means. 19. The head device according to claim 16, wherein when the head device records or reproduces a layer other than the specific layer, the head device controls the correction device using an index stored in the storage device. The optical information recording / reproducing method according to one of the above.

30. The optical information recording / reproducing method according to any one of claims 16 to 29, wherein the optical information recording / reproducing method is applied only to reproduction for performing only reproduction of information on the information storage medium.