An optical disc and an optical disc apparatus

Abstract

This invention discloses an optical disc and an optical disc device. The optical disc includes a groove bottom channel and a groove top channel formed by spiral grooves. Both the groove bottom channel and the groove top channel have a plurality of recording blocks capable of recording data. Each recording block contains a predetermined number of frames, and each frame has a frame synchronization field of length T at a predetermined position. In adjacent groove bottom channels and groove top channels along the radial direction of the optical disc, the recording block in the groove bottom channel is the first recording block, and the recording block in the groove top channel is the second recording block. The first recording block and the second recording block are offset from each other by an angular offset length along the circumference of the optical disc. The optical disc disclosed in this invention has the advantages of a small reading signal amplitude during optical disc reading, thus eliminating the need for a large dynamic range and very high SNR performance in the reading signal processing circuit, thereby simplifying the implementation of the reading signal processing circuit.

Description

Technical Field

[0001] This invention relates to the field of information storage technology, and in particular to an optical disc and an optical disc device. Background Technology

[0002] Currently, various optical discs exist as media for storing images and data, such as DVDs and Blu-ray discs (hereinafter referred to as BD). From the perspective of space efficiency in data storage, there are technologies that increase the recording capacity per unit volume without increasing the cost of the optical disc, namely, increasing line density and channel density.

[0003] Among techniques for improving line density, Partial Response Most Likelihood (PRML) signal processing is widely used. Optical discs record binary signals of markers and spaces in their channels. When reading this binary signal, the bandwidth of the detected read signal is limited to the low-frequency range based on the beam's detection frequency characteristics. This is due to the simultaneous reading of multiple markers and spaces according to the beam's diffraction limit, a phenomenon known as inter-symbol interference (ISI). PRML signal processing involves an adaptive equalization circuit that equalizes the reproduced signal waveform to approximate the desired waveform based on ISI, and an optimal circuit that estimates the recorded binary signal by comparing and selecting the equalized read signal waveform and the desired waveform. To improve line density, PRML signal processing techniques that increase the ISI bandwidth are used.

[0004] As a technique to improve channel density, there is slot top (between slots) - slot bottom (groove) recording and reading technology. This technology has been used in DVD-RAM to improve channel density by recording data that was previously only recorded at the slot bottom or slot top in the slot bottom and slot top. Furthermore, a crosstalk cancellation technique for reducing crosstalk components from the channel is disclosed.

[0005] As a crosstalk cancellation technique, the read signal waveform of the target channel (which is used to read data) and the reproduced signal waveforms from two adjacent channels are simultaneously input into the adaptive equalization circuit of the PRML signal processing technique. There is also a multi-track crosstalk cancellation technique (Patent Document 3) that obtains the equalized read signal waveform by eliminating noise crosstalk components from adjacent channels.

[0006] In addition, there is a 1-track crosstalk cancellation technique that divides the beam of reflected light from the object channel of the read data into multiple regions for detection, and simultaneously inputs these detected multiple read signal waveforms into the adaptive equalization circuit of PRML signal processing technology to eliminate crosstalk components and obtain the equalized read signal waveform (Patent Document 4).

[0007] Data recording on optical disc channels is performed in units of a predetermined number of frame-sized recording blocks. Each recording block includes a runin region for determining block boundaries and a data region. If the block boundaries cannot be correctly detected and the position determined during reading, data cannot be read. Therefore, a recording mode that more easily detects, for example, runin boundaries and determines position is needed. Existing technologies involve synchronization modes such as FrameSync for position determination within the runin and data regions.

[0008] Optical discs record data in a format consisting of recording blocks at the bottom of the groove and the top of the slot. The Runin and FrameSync modes are composed of long markers and spaces, and are contained in predetermined positions for easy detection during reading. In these mode sections, even when reading from only one channel at the bottom of the groove or the top of the slot, the amplitude of the detected read signal is more likely to increase, thus making it easier to detect.

[0009] If the same running pattern is recorded in the running regions of recording blocks that are adjacent at the same angular position at the top and bottom of the trench, the amplitude of the regenerated signal during reading will increase in the long mark and long space portions. To suppress the increase in the reading signal amplitude, the running pattern recorded in the bottom of the trench and the running pattern recorded in the top of the trench are different from each other (Patent Document 5).

[0010] However, in order to increase the recording density of optical discs, the channel spacing (the interval between grooves) is reduced. Not only in the runin area, but also in adjacent positions at the bottom of the groove and the top of the slot, the same recording pattern will overlap, making the reading signal amplitude very large. This requires a large dynamic range in the reading signal processing circuit. Furthermore, in order to process the reading signal correctly even in the small amplitude part, very high SNR performance is required, which makes the implementation of the reading signal processing circuit difficult.

[0011] [Patent Document 1] Japanese Patent Application Publication No. 2003-141823

[0012] [Patent Document 2] Japanese Patent Application Publication No. 10-261272

[0013] [Patent Document 3] Japanese Patent Application Publication No. 2012-79385

[0014] [Patent Document 4] Patent No. 5810300

[0015] [Patent Document 5] Patent No. 6803518 (US10,002,633b2)

[0016] Patent document 5 describes different modes for suppressing interference from runin at the top and bottom of the trench.

[0017] However, as mentioned earlier, if the channel spacing is reduced in order to further increase the recording density of the disk, the runin mode alone cannot completely solve the problem, and new challenges will arise. Summary of the Invention

[0018] The present invention addresses the above-mentioned problems by proposing an optical disc.

[0019] The technical means employed in this invention are as follows:

[0020] An optical disc includes a groove bottom channel and a groove top channel formed by spiral grooves. Both the groove bottom channel and the groove top channel have a plurality of recording blocks capable of recording data. Each recording block contains a predetermined number of frames, and each frame has a frame synchronization field of length T at a predetermined position. In adjacent groove bottom channels and groove top channels along the radial direction of the optical disc, the recording block in the groove bottom channel is a first recording block, and the recording block in the groove top channel is a second recording block. The first recording block and the second recording block are offset from each other by an angular offset length along the circumferential direction of the optical disc.

[0021] Furthermore, the offset length of the first recording block and the second recording block in the circumferential direction of the optical disc by an angular position is such that the projections of the frame synchronization domain of the first recording block and the frame synchronization domain of the second recording block on the same ring of the optical disc do not overlap.

[0022] Furthermore, the offset length L of the angular position is:

[0023] L≥T + 0.25xλ / NA (1)

[0024] Where: T is the frame synchronization domain length, λ is the wavelength, and NA is the number of apertures.

[0025] Furthermore, the wavelength λ = 405 nm; the aperture number NA ≥ 0.85.

[0026] Furthermore, the offset length L of the angular position is less than the initial response length S of the tracking control signal of the optical disc device, the tracking control signal being used to control the laser head of the optical disc device to follow and scan the groove bottom channel and / or slot top channel of the optical disc.

[0027] An optical disc apparatus for recording and reading the optical disc described in this application, comprising,

[0028] A recording signal processing circuit that converts data to be recorded or read into recording or reading signals in units of a specified number of frames;

[0029] A laser head that records data by illuminating a channel on an optical disc with a wavelength of λ through an objective lens with an aperture number of NA and controlling the power of the laser based on the recording signal;

[0030] The recording signal processing circuit controls the laser head to deflect sequentially in the adjacent groove bottom channel and slot top channel in the radial direction of the optical disc by a set angular offset length, so as to record and read the first recording block in the groove bottom channel and the second recording block in the slot top channel.

[0031] Furthermore, the offset length L of the angular position is:

[0032] L≥T + 0.25xλ / NA (1)

[0033] Where: T is the frame synchronization domain length, λ is the wavelength, and NA is the number of apertures.

[0034] Furthermore, the wavelength λ = 405 nm; the aperture number NA ≥ 0.85.

[0035] Furthermore, the recording signal processing circuit includes a tracking control circuit for controlling the laser head to follow and scan the groove bottom channel and / or groove top channel of the optical disc, wherein the initial response length S of the tracking control signal of the tracking control circuit is greater than or equal to the offset length L of the angular position.

[0036] Compared with existing technologies, the optical disc disclosed in this invention has the following beneficial effects: The optical disc disclosed in this invention, because it has recording areas at both the bottom of the groove and the top of the slot, increases the recording density. Simultaneously, because the recording areas on adjacent groove bottom and top channels are offset along the circumference of the disc, the operating areas of the two recording areas on adjacent groove bottom and top channels do not completely overlap in the circumferential direction. This prevents the aforementioned pattern portions from overlapping at adjacent positions at the bottom of the groove and the top of the slot, reducing the correlation of signals within the operating areas of adjacent channels. This, in turn, reduces the amplitude of the read signal during disc reading. As a result, a large dynamic range and very high SNR performance are not required in the read signal processing circuit, making the implementation of the read signal processing circuit easier. Furthermore, by setting an offset that does not affect the servo controlling the position of the light spot illumination, stable recording and reading can be achieved. Attached Figure Description

[0037] Figure 1 This is a magnified planar schematic diagram of the recording block area arrangement and signal processing of an optical disc channel, as disclosed in the prior art.

[0038] Figure 2This is a magnified planar schematic diagram of the arrangement of recording block regions and signal processing of the optical disc channel disclosed in this invention.

[0039] Figure 3 The signal waveform diagram of scanning and reading a mark of a certain reference length recorded on an optical disc channel.

[0040] Figure 4 This is a waveform diagram of the tracking error signal when the offset length between the first and second recording blocks of the optical disc disclosed in this invention is too large.

[0041] Figure 5 This is a circuit diagram of the optical disc device disclosed in this invention. Detailed Implementation

[0042] Hereinafter, embodiments will be described in detail with appropriate reference to the accompanying drawings. However, sometimes unnecessary detailed descriptions will be omitted. For example, detailed descriptions of known matters or repeated descriptions of substantially the same configurations may be omitted. This is to avoid unnecessary verbosity in the following description and to facilitate understanding by those skilled in the art.

[0043] It should be noted that the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the contents of this disclosure, and are not intended to limit the subject matter described in the claims.

[0044] Figure 1 For recording and reading from previous optical discs. For example... Figure 1 As shown, the optical disc includes alternating groove bottom channels and slot top channels arranged along the radial direction of the disc. Specifically, the disc-shaped optical disc has multiple grooves spirally processed, and a spiral slot top structure is formed between two adjacent grooves. Both the groove bottom and the slot top can be used for data recording, thus forming the groove bottom channel and the slot top channel. Figure 1 The diagram schematically illustrates alternating arrangements of Groove 1, Land 1, Groove 2, and Land 2.

[0045] Data recording on an optical disc channel is performed in defined record blocks. Each record block includes a runin region for identifying block boundaries and a data region. If the block boundaries cannot be correctly detected and the position determined during reading, data cannot be read. Therefore, a recording mode that more easily detects, for example, runin boundaries and determines position is needed. Existing technologies involve synchronization modes such as FrameSync for position determination within the runin and data regions. To ensure easier detection of synchronization modes, each synchronization mode consists of a long marker with increased read signal amplitude and a space. For example... Figure 1As shown, when reading slot 1, the amplitude of the read signal increases in the RuninL mode of the running area (A in the figure) and the FrameSync position in the data area (B in the figure).

[0046] like Figure 1 As shown, in the past, the recording areas of optical disc channels were configured by placing recording blocks at the same angular position in two adjacent channels (bottom of the trench and top of the slot). The RuninG mode for recording blocks in the bottom of the trench channel and the RuninL mode for recording blocks in the top of the slot channel were different modes to suppress the increase in read signal amplitude due to mutual interference. However, when the polarity of the FrameSync mode (FSY) markers and spaces in the bottom of the trench and top of the slot is the same, as shown... Figure 1 As shown, the amplitude of the slot top 1 read signal becomes very large (amplitude 1 in the figure). Because the read signal amplitude is large in the FrameSync section of the slot top 1 read signal, a large dynamic range is required in the circuitry processing the read signal. The amplitude of the slot top 1 read signal in the FrameData section, which records user data (amplitude 2 in the figure), is smaller than amplitude 1. Therefore, to correctly decode user data from the read signal of the FrameData section with its smaller amplitude, very high SNR performance is required, making the implementation of the read signal processing circuitry difficult.

[0047] Figure 2 The recording and reading of an optical disc according to the present invention are illustrated. Figure 2 As shown, the configuration of the recording blocks in the optical disc channels disclosed in this invention allows the recording blocks in two adjacent channels (groove bottom and slot top) to be offset by a certain angle (in the same circumferential direction) in the circumferential direction of the optical disc, and the runin regions of adjacent groove bottoms and slot tops do not overlap with the synchronization patterns composed of long marks and spaces in FrameSync. In this invention, because the synchronization patterns of the groove bottoms and slot tops do not overlap in the circumferential direction, the problem of overlap in the groove bottoms and slot tops is avoided. Figure 1 The Land1 read signal, as shown, exhibits an excessively large amplitude. Figure 2 As shown, the amplitude of the read signal in the synchronization pattern section (amplitude 3 in the figure) becomes relatively small. This is because the amplitude is smaller than... Figure 1 As shown in the figure, amplitude 1, therefore there is no need to increase the dynamic range of the read signal processing circuit. Since the difference between amplitude 2 of the FrameData section and amplitude 3 of the synchronization mode section becomes smaller, even when processing read signals with small amplitudes, SNR performance and dynamic range are both taken into account, and the read signal processing circuit becomes simpler.

[0048] As a way to stagger the recording positions so that Figure 2The amount L shown is the amount of the synchronous patterns at the bottom and top of the trench that do not overlap.

[0049] L≥T + 0.25xλ / NA (1)

[0050] In equation (1), T represents the frame synchronization domain length (FrameSync pattern length); λ represents the wavelength; NA represents the number of apertures; λ = 405 nm; NA ≥ 0.85.

[0051] Figure 3 The offset L is described. Figure 3 The diagram illustrates a marker of a certain reference length recorded on an optical disc channel and the waveform of the signal when read using a spot of light from the marker shown in the diagram. The spot is larger than the recorded marker. Therefore, the waveform of the read signal obtained by scanning the channel with the spot is such that, relative to the marker, the signal amplitude begins to change from a position close to the end of the spot, with the largest amplitude at the position where the marker position and the center position of the spot overlap, forming a wider, mountain-shaped waveform than the recorded marker.

[0052] Therefore, when multiple markers are recorded within a range smaller than the width of the mountain shape, Figure 3 The waveform of the reproduced signal shown will become multiple overlapping interference waveforms depending on the marker positions. Conversely, when multiple markers are recorded at positions larger than the width of the hill, the overlap of the readout signal waveforms is small, and no interference is formed. The amplitude at which the interference is large and the separation and discrimination of the readout signal corresponding to the marker becomes difficult is called the diffraction limit. Figure 3 The length of the read signal width, which is half the amplitude of the waveform shown, is the diffraction limit, calculated from 0.5xλ / NA.

[0053] The offset L of the recording position in this invention is obtained by adding the length T of the FrameSync and the interference width (a length greater than half the diffraction-limited length) of the end of the FrameSync, 0.25xλ / NA, as shown in equation (1), i.e., L≥T+0.25xλ / NA. This prevents the reading signal amplitude from being too large due to the overlap of the FrameSync at the top and bottom of the trench.

[0054] In addition, if the recording position is significantly deviated from the above-mentioned position, a mixture of unrecorded and recorded areas will be generated at the beginning and end of the recording block. Figure 4 This indicates the channel state where a mixing phase has occurred. The tracking error signal is used to control the illumination position (tracking) of the light spot, ensuring the light spot scans the channel at the center. If the tracking error signal is 0, it is considered to indicate that the tracking position of the light spot is at the center of the channel. However, to increase density, if adjacent trench bottom and trench top channels become very close, the tracking error signal will be affected by whether or not a marker is recorded on the adjacent channel. Figure 4As shown, even if the tracking position of the light spot is at the center of the channel, the tracking error signal becomes non-zero, and the tracking position of the light spot will be controlled to a position off-center from the channel. To prevent the impact of such tracking position deviation from the recording position from increasing, it is necessary to suppress the amount L of deviation from the recording position to a necessary minimum. Tracking position control based on the tracking error signal has the characteristic of responding to low-frequency layer components. Shortening the offset L of the recording position makes the response of the tracking position control sufficiently small, i.e., the offset length L of the angular position is less than the length S of the tracking control start response.

[0055] Figure 5 This is a structural diagram of an optical disc device 10 based on the present invention, used for recording and reading optical discs. Figure 5 As shown, the optical disc device 10 includes: a laser head 101, a spindle motor 102, a servo controller 103, a laser drive circuit 104, a modulation circuit 105, an error correction encoding circuit 106, a read signal detection circuit 107, a PRML circuit 108, a demodulation circuit 109, an error correction decoding circuit 110, a servo signal detection circuit 111, an I / F circuit 112, a memory circuit 113, a system controller 114, and a read-only memory (ROM) 115.

[0056] The optical disc device 10 records and reads user data on the optical disc 100. On the optical disc 100, a spiral channel is formed from the inner circumference to the outer circumference. The channel includes a groove bottom track formed by the bottom of the groove and a groove top channel formed adjacently by the top of the groove. Both the groove bottom channel and the groove top channel can be used to record user data.

[0057] The spindle motor 102 rotates the optical disc 100. By shining a light beam onto the optical disc 100, the laser head 101 records user data onto the optical disc 100 and reads user data from the optical disc 100.

[0058] The servo controller 103 controls the laser head 101 and the spindle motor 102, controlling the laser beam irradiated from the laser head 101 onto the optical disc 100 to scan along a track set on the optical disc 100, and controlling the movement of the target channel to be accessed. The servo controller 103 controls the position of the laser head 101 and the rotation speed of the spindle motor 102, so that the laser head 101 scans the optical disc 100 at a predetermined linear speed.

[0059] I / F circuit 112 receives user data to be recorded on optical disc 100 from host 116 and stores it in memory circuit 113. Additionally, I / F circuit 112 reads optical disc 100 and transmits the user data stored in memory circuit 113 to host 116. User data stored in memory circuit 113 can be sent to other internal blocks, or conversely, user data received from other internal blocks can be stored in memory circuit 113.

[0060] Error correction coding circuit 106 adds parity check codes for error correction to user data received from I / F circuit 112, thereby generating coded data.

[0061] The modulation circuit 105 receives encoded data from the error correction coding circuit 106 and generates a modulated signal modulated according to a predetermined modulation symbol. This modulated signal is recorded on a channel on the optical disc 100.

[0062] The laser drive circuit 104 converts the modulation signal into optical pulses to correctly form marks on the optical disc 100 and drives the semiconductor laser of the laser head 101. The heat from the irradiated beam forms marks on the optical disc 100.

[0063] On the other hand, the user data recorded on the optical disc 100 is reproduced by the read signal detection circuit 107, the PRML circuit 108, the demodulation circuit 109, and the error correction decoding circuit 110.

[0064] The laser head 101 illuminates the optical disc 100 with a light beam and detects the reflected light from the optical disc 100. The laser head 101 outputs a light quantity signal based on the detected reflected light.

[0065] The servo signal detection circuit 111 generates a focus error signal and a tracking error signal based on the light quantity signal detected by the laser head 101. These signals are the source for the servo controller 103 to control the beam to focus on the channel.

[0066] After reducing the noise of the light signal through a low-pass filter, the reconstructed signal detection circuit 107 outputs a digital reconstructed signal sampled by an A / D converter.

[0067] The PRML circuit 108 decodes the digital readout signal to generate a decoded signal. Specifically, the PRML selects the closest expected value waveform from a comparison between the equalized reproduction signal obtained by inputting the digital readout signal to an adaptive equalization circuit and the expected value waveform. This selected waveform becomes the basis of the expected value waveform and is output as the decoded signal. The characteristics of the expected value waveform are determined by factors such as... Figure 3 The frequency characteristics of the detected beam shown are affected by bandwidth limitations.

[0068] The demodulation circuit 109 demodulates the encoded data from the decoded signal according to the predetermined modulation symbol.

[0069] The error correction decoding circuit 110 corrects errors in the demodulated encoded data and restores the user data.

[0070] ROM115 is made of flash memory. ROM115 stores the program used by system controller 114 to control the entire optical disc device 10.

[0071] System controller 114 reads and executes the program stored in ROM 115, thereby controlling various circuits and communication with host 116. Additionally, for convenience, Figure 5 The arrows indicating control of each component from the system controller 114 are omitted. In this embodiment, the system controller 114 of the optical disc device 10 controls the operation of circuits associated with the recording and reading of user data.

[0072] [The operation of the optical disc device]

[0073] The operation of the optical disc device 10 related to the present invention will now be described.

[0074] I / F circuit 112 acquires the recording data sent from host 116 and the logical address of the recording destination in optical disc 100. I / F circuit 112 divides the recording data into data blocks of predetermined units and transmits each data block to error correction coding circuit 106.

[0075] Error correction coding circuit 106 adds parity check codes to the recorded data, in blocks, to correct errors during rereading. Modulation circuit 105 modulates the recorded data with the added parity check codes onto a modulation signal according to prescribed modulation rules and the format of the recorded blocks. Figure 2 As shown, a Runin region is added to each data block, which is divided into FrameData and becomes the modulation signal of the record block with FrameSync inserted.

[0076] To correctly form recording marks on the optical disc 100, the laser drive circuit 104 converts the recording pulse waveform into a recording pulse waveform based on the modulation signal and outputs the recording pulse waveform to a drive signal for driving the semiconductor laser. The semiconductor laser of the laser head 101 irradiates the optical disc 100 with laser pulses according to the drive signal at the position on the optical disc 100 corresponding to the logical address of the recording target. Thus, the mark corresponding to the modulation signal is recorded on the channel of the optical disc 100.

[0077] System controller 114 controls the aforementioned recording operation. Based on the logical address of the recording destination obtained by I / F circuit 112, system controller 114 determines the recording position on optical disc 100 and controls servo controller 103 to move laser head 101 to the target position. System controller 114 operates error correction encoding circuit 106 before laser head 101 reaches the track serving as the target position, and operates modulation circuit 105 and laser drive circuit 104 to perform recording when laser head 101 reaches the target position. The target position for recording is controlled as described above, only... Figure 2 The L shown is offset by the bottom channel and the top channel of the trench.

[0078] The reading operation of the optical disc device 10 in this embodiment will be described next.

[0079] I / F circuit 112 acquires the logical address of the read destination from optical disc 100 sent from host 116. System controller 114 controls each circuit to play user data at the requested logical address.

[0080] System controller 114 controls servo controller 103 to move laser head 101 onto the target channel. Laser head 101 illuminates the target channel with a laser and outputs a light quantity signal from the reflected light. Read signal detection circuit 107 outputs a digital read signal obtained by sampling the light quantity signal through an A / D converter.

[0081] The digital readout signal is input to the PRML circuit 108. The PRML signal processing selects the closest expected value waveform from the equalized playback signal obtained by inputting the digital playback signal to the adaptive equalization circuit and compares it with the expected value waveform. The pattern signal that will become the basis of the expected value waveform is output as the decoding signal.

[0082] Demodulation circuit 109, based on the target channel being played, modulates the signal with the target channel. Figure 2 The timing of the runin synchronization pattern is detected by matching the offset L of the recording position shown, and the start position of the recording block is determined. Furthermore, FrameSync is detected to determine the correction of the playback position in units of FrameData. Based on the determined position, the encoded data is demodulated from the decoded signal using predetermined modulation symbols. In the optical disc apparatus of the present invention, by offsetting the position of the recording block in the groove bottom channel and groove top channel, the quality of the read signal of the read signal detection circuit 107 and the PRML circuit 108 is more easily ensured, and the detection error rate of the runin and FrameSync synchronization modes in the demodulation circuit 109 can be reduced.

[0083] The error correction decoding circuit 110 corrects errors in the demodulated encoded data and obtains the result of recovering the user data in the memory circuit 113.

[0084] The system controller 114 controls the transmission of user data obtained from the memory circuit 113 to the host 116 via the I / F circuit 112, thereby completing the read operation.

[0085] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. An optical disc, comprising a groove bottom channel and a groove top channel formed by spiral-shaped grooves, wherein both the groove bottom channel and the groove top channel have a plurality of recording blocks capable of recording data, each recording block containing a predetermined number of frames, the frames having a frame synchronization field of length T at a predetermined position; characterized in that: In the adjacent groove bottom channel and slot top channel in the radial direction of the optical disc, the recording block in the groove bottom channel is the first recording block, and the recording block in the slot top channel is the second recording block; the first recording block and the second recording block are offset by an angular offset length in the circumferential direction of the optical disc; The offset length L of the angular position is: L≥T + 0.25xλ / NA(1) Where: T is the frame synchronization domain length, λ is the wavelength, and NA is the number of apertures; The offset length L of the angular position is less than the initial response length S of the tracking control signal of the optical disc device. The tracking control signal is used to control the laser head of the optical disc device to follow and scan the bottom groove channel and / or top groove channel of the optical disc.

2. The optical disc according to claim 1, characterized in that: The first recording block and the second recording block are offset by an angular position in the circumferential direction of the optical disc such that the projections of the frame synchronization domains of the first recording block and the second recording block onto the same ring of the optical disc do not overlap.

3. The optical disc according to claim 2, characterized in that: The wavelength λ = 405 nm; the aperture number NA ≥ 0.

85.

4. An optical disc apparatus for recording and reading the optical disc according to any one of claims 1 to 3, characterized in that: include, A recording signal processing circuit that converts data to be recorded or read into recording or reading signals in units of a specified number of frames; A laser head that records data by illuminating a channel on an optical disc with a wavelength of λ through an objective lens with an aperture number of NA and controlling the power of the laser based on the recording signal; The recording signal processing circuit controls the laser head to offset in the adjacent groove bottom channel and slot top channel in the radial direction of the optical disc by a set angular offset length in order to record and read the first recording block in the groove bottom channel and the second recording block in the slot top channel. The offset length L of the angular position is: L≥T + 0.25xλ / NA(1) Where: T is the frame synchronization domain length, λ is the wavelength, and NA is the number of apertures; The recording signal processing circuit includes a tracking control circuit for controlling the laser head to follow and scan the groove bottom channel and / or groove top channel of the optical disc. The initial response length S of the tracking control signal of the tracking control circuit is greater than the offset length L of the angular position.

5. The optical disc device according to claim 4, characterized in that: The wavelength λ = 405 nm; the aperture number NA ≥ 0.85.

Images