JP2006302419A - Optical disk player - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical disk player using an optimization processing circuit (playback part) capable of optimizing an electric signal input from a PU (optical pickup part) without using a test signal generator or waveform observation equipment and without expanding an operation environment of genetic algorithm. <P>SOLUTION: The optical disk player has the optical pickup part (PU 2) for reading a plurality of record bits recorded on an optical disk 1, a buffer part (BUFF 9) for storing a signal obtained by photoelectrically converting information read by the optical pickup part, a control part 9a for reading the signal from the buffer part, a response characteristic adjusting part (lowpass waveform adjusting part 12) for adjusting a response characteristic of the signal read by the control part 9a, a boost adjusting part 11 for amplifying the high frequency of the signal read by the control part, a gain adjusting part 10 for adjusting the low frequency region gain of the signal read by the control part, and an adding part 13 for adding signals whose response characteristic and high frequency region are amplified and signals whose low frequency region gain is adjusted. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical disc reproducing apparatus, and an optimization processing circuit (reproducing unit) that uses a light reception signal of reflected light of a recording bit obtained by irradiating a recording bit recorded on an optical disc as an optimum information signal. The present invention relates to an optical disc reproducing apparatus having

  The reflected light of the recording bit obtained by irradiating the recording bit recorded on the optical disk with the light beam is affected by the light beam, and the reflected light shape of the recording bit is deformed. In particular, when the recording bit is small or when the interval between two recording bits is narrow, the deformation of the reflected light shape is remarkable.

For this reason, in the conventional optical disk reproducing apparatus, in order to remove the deformation of the reflected light shape, after receiving the reflected light and converting it into an electric signal, optimization is performed to remove the deformation of the reflected light shape from the electric signal. An optimization processing circuit was used.
FIG. 8 is a block diagram for explaining a conventional optical disk reproducing apparatus using this optimization processing circuit. FIG. 8A is a diagram showing the configuration of the optical disk reproducing apparatus, and FIG. It is a figure for demonstrating the structure and adjustment method of an optimization processing circuit.
FIG. 9 is a diagram showing frequency characteristics of the optimization processing circuit.

Next, a conventional optical disk apparatus will be described with reference to FIGS.
As shown in FIG. 8 (A), the conventional optical disk reproducing apparatus receives the reflected light by emitting an optical beam and irradiating the recording bit of the optical disk by emitting a light beam on the surface as characters, images, etc. as recording bits. An optical pickup (PU51) that converts the electric signal into an electric signal, and an optimization processing circuit 52 that receives the electric signal T0 input from the PU51 and outputs an electric signal T1 that has been optimized by removing the deformation of the reflected light shape; The AGC 53 that automatically adjusts the signal level of the electrical signal T1 and outputs the electrical signal T2 of a predetermined level, the A / D 54 that converts the electrical signal T2 that is an analog signal into the digital signal T3, and the digital signal T3 A decoding circuit 55 that decodes the information signal T4 such as characters and images, and corrects an error in the signal arrangement of the decoded information signal T4 and outputs a digital output signal T5. And error correction circuit 56, the PLL57 for outputting a clock F1 of a predetermined frequency in an electric signal T1 to the reference, and a.

  As shown in FIG. 8 (B), an optimum electric signal T1 that is an input of the electric signal T0 input from the PU 51 and that is optimized by removing the deformation of the reflected light shape, which constitutes the conventional optical disk reproducing apparatus, is configured. The processing circuit 52 outputs a low-frequency waveform adjusting unit 100 that outputs a correction signal T100 obtained by adjusting the delay amount and gain of the low-frequency waveform of the electric signal T0, and the high-frequency waveform delay amount and gain of the correction signal T100. The high-frequency waveform adjusting unit 101 that outputs the adjusted correction signal T101, and the noise removal circuit 102 that removes noise in the frequency band of the correction signal T101 that has no recording bit information of the optical disc in particular.

Next, an optimization process of the optimization processing circuit 52 that obtains an electric signal from which the deformation of the reflected light shape is removed will be described.
Since the electric signal T0 having a reduced frequency component of the high frequency having the PU input signal frequency characteristic shown in FIG. 9 is input from the PU 51 to the optimization processing circuit 52, this is recorded on the optical disc 50 shown in FIG. Optimized processing frequency characteristics of the information signal corresponding to the bit.

  For this purpose, first, a test signal shown in FIG. 9 having a flat frequency characteristic over the entire frequency band is input from the test signal generator 103 instead of the electric signal T0. Then, the waveform observation device 104 observes the electric signal T1 that is the output of the optimization processing circuit 52, and the delay amount adjustment B0 and the gain adjustment of the low-frequency waveform so that the frequency characteristic of the output signal shown by the solid line in FIG. B1 is performed by the low frequency waveform adjustment unit 100, and the high frequency waveform delay unit B2 and the gain adjustment B3 are performed by the high frequency waveform adjustment unit 101. Next, a test signal having only a reference frequency is input from the test signal generator 103 to the optimization processing circuit 52. This test signal is input to the PLL 57 via the optimization processing circuit 52, and the frequency adjustment B4 is performed by the PLL frequency adjustment unit 57a. However, the frequency measuring device 105 is adjusted so that the clock F1 has a predetermined frequency.

  In this way, the frequency characteristic of the output signal (T1) shown in FIG. 9 for taking out only the optimization processing circuit 52 and obtaining the optimization processing frequency characteristic of the information signal corresponding to the recording bit as shown in FIG. Optimal processing can be performed.

Patent Document 1 describes that a genetic algorithm is used instead of the frequency characteristic of the output signal (T1) as shown in FIG. This is because the optimization data for the boost characteristics (QB value) and amplitude level are stored in advance in the microcomputer for the multiple types, and the optimization data with the least error is extracted when using the optical disk playback device. Is to do.
JP 2003-109227 A

However, in the conventional optimization processing circuit 52 that performs the optimization processing by the test signal using the test signal generator 103 and the waveform observation device 104, the light beam is emitted to irradiate the recording bit of the optical disc 50 and the reflected light is emitted. The characteristics of the electrical signal obtained in the PU 51 that receives light and converts it into an electrical signal are not necessarily constant. For example, the frequency characteristics and the gain of the electrical signal are different in each optical disc reproducing apparatus. Even if the optimization processing circuit 52 is strictly adjusted so as to obtain the frequency characteristic of T1), when the optimization processing circuit 52 is actually used by being incorporated in an optical disk reproducing apparatus, an error occurs. There was a point.
Further, in the method of performing the optimization process using the genetic algorithm described in Patent Document 1 instead of the frequency characteristics as shown in FIG. 9, the optimization process takes time, and the genetic algorithm There was a problem that the operating environment had to be expanded.

  Therefore, the present invention has been made to solve the above-described problems, and an optical disc can be used without using a test signal generator or a waveform observation device and without adding an operating environment for a genetic algorithm. It is an object of the present invention to provide an optical disc reproducing apparatus using an optimization processing circuit that makes a light reception signal of reflected light of a recording bit obtained by irradiating a recorded recording bit with a light beam as an optimum information signal.

  According to a first aspect of the present invention, there is provided an optical disc playback apparatus having a playback section (optimization processing circuit) that reads a plurality of recording bits recorded in a data area of an optical disk and plays back information. An optical pickup that reads a plurality of recording bits recorded in a data area of the optical disc as optical information, a buffer unit that stores an electrical signal obtained by photoelectrically converting optical information read by the optical pickup as the information signal, and the buffer A control unit that reads out the information signal from the unit, a response characteristic adjustment unit that adjusts a response characteristic of the information signal read out by the control unit, and a high-frequency region of the information signal read out by the control unit A boost adjustment unit that amplifies the information signal, and a gain adjustment unit that adjusts a gain in a low frequency region of the information signal read by the control unit And an adder for adding the response signal, the information signal in which the high frequency region is amplified, and the information signal in which the gain in the low frequency region is adjusted. It is.

 According to the present invention, in an optical disc playback apparatus having a playback unit that reads a plurality of recording bits recorded in a data region of an optical disc and plays back information, the playback unit (optimization processing circuit) An optical pickup that reads a plurality of recording bits recorded on the optical information as optical information, a buffer unit that accumulates electrical signals obtained by photoelectrically converting optical information read by the optical pickup as information signals, and reads information signals from the buffer unit A control unit, a response characteristic adjustment unit that adjusts the response characteristic of the information signal read by the control unit, a boost adjustment unit that amplifies the high-frequency region of the information signal read by the control unit, and a read by the control unit A gain adjusting unit that adjusts the gain of the low frequency region of the received information signal, the response characteristics, the information signal in which the high frequency region is amplified, and the low frequency region And an addition unit for adding the adjusted information signal, and the reflected light reception signal of the recording bit obtained by irradiating the recording beam recorded on the optical disc with the light beam is the optimum information signal. can do.

An optical disk reproducing apparatus according to an embodiment of the present invention will be described below with reference to FIGS.
FIG. 1 is a diagram showing a block diagram for explaining an optical disk reproducing apparatus using an optimization processing circuit according to an embodiment of the present invention, and FIG. 1 (A) is a diagram showing a configuration of the optical disk reproducing apparatus. FIG. 7B is a diagram for explaining the configuration of the optimization processing circuit and the adjustment method.
FIG. 2 is a diagram showing a plurality of recording bits recorded in the data area of the optical disc, and FIG. 2A is a diagram showing the shapes of the plurality of recording bits recorded in the data area of the optical disc. ) Is a diagram showing a reflected light shape and PU output signal on a PU reflected by irradiating a plurality of recording bits recorded in the data area of the optical disc with a light beam, and (C) is an optimization process. It is a figure which shows the reproduction signal and reproduction shape by which the PU output signal was optimized by the circuit.
FIG. 3 shows a diagram in which an electrical signal is converted into a digital signal, (A) shows a diagram in which a PU output signal is converted into a digital output signal, and (B) shows a digitally output reproduction signal that has been optimally processed. The figure converted into the signal is shown, (C) shows the figure which converted the excessive reproduction signal which was excessively processed optimally into the digital output signal.
FIG. 4 is a diagram illustrating frequency characteristics of each adjustment portion of the optimization processing circuit.
FIG. 5 is a diagram showing a correction state of a reproduction signal, (A) is a diagram showing a correction state of a rising edge, and (B) is a diagram showing a correction state of a falling edge.
FIG. 6 is a flowchart illustrating adjustment of the optimization processing circuit in the process adjustment.
FIG. 7 is a diagram illustrating a flowchart for adjusting the optimization processing circuit for set adjustment.

  As shown in FIG. 1 (A), an optical disk reproducing apparatus according to an embodiment of the present invention irradiates a recording bit of an optical disk by emitting a light beam and recording an optical disk 1 on which characters, images, etc. are recorded as recording bits. PU2 that receives the reflected light and converts it into an electrical signal, and an optimization processing circuit 3 that receives the electrical signal S0 input from PU2 and outputs the electrical signal S1 that is optimized by removing the deformation of the reflected light shape. (Reproducing unit), AGC 4 that automatically adjusts the signal level of the electric signal S1 and outputs an electric signal S2 of a predetermined level, and A / D5 that converts the electric signal S2 that is an analog signal into a digital signal D0 and outputs it A decoding circuit 6 that decodes the digital signal D0 into an information signal D1 such as characters and images, and an error that corrects an error in the signal arrangement of the decoded information signal D1 and outputs a digital output signal D2 Positive circuit 7, and PLL8 for outputting a clock F0 of predetermined frequency in the electrical signal S1 to the reference, and a.

  Then, as shown in FIG. 1B, the electric signal S0 input from the PU 2 constituting the optical disc reproducing apparatus according to the embodiment of the present invention is input, and the electric signal optimized by removing the deformation of the reflected light shape is input. The optimization processing circuit 3 that outputs S1 includes a buffer unit (BUFF9) that accumulates an electrical signal obtained by photoelectrically converting optical information read by the optical pickup PU2 as an information signal, and a control unit 9a that reads the information signal from the buffer unit. A response characteristic adjusting unit (low-frequency waveform adjusting unit 12) that adjusts the response characteristic of the information signal read by the control unit 9a, and a boost adjustment that amplifies the high-frequency region of the information signal read by the control unit 9a Unit 11, gain adjustment unit 10 that adjusts the gain in the low frequency region of the information signal read out by control unit 9 a, response characteristics, the information signal in which the high frequency region is amplified, and the low frequency region An addition unit 13 for adding the information signal whose gain is adjusted, an LPF band adjustment unit 14 for adjusting the trailing edge of the signal, and a noise removal unit 15 for removing noise in a frequency band without recorded bit information of the optical disc. Composed.

Next, the operation will be described.
As shown in FIG. 1A, the optical disk reproducing apparatus according to the embodiment of the present invention emits a light beam from the PU 2 to the optical disk 1 on which characters, images, etc. are recorded as recording bits on the surface, and records the recording bits of the optical disk. Irradiated and reflected light is received again by PU2, converted into an electric signal S0 and output. Next, the optimization processing circuit 3 removes the deformation of the reflected light shape of the electric signal S0 input from the PU 2 and outputs the electric signal S1, and the signal level of the electric signal S1 is automatically adjusted by the AGC 4 to a predetermined level. Is converted to a digital signal D0 by A / D5. Then, the decoding circuit 6 decodes the digital signal D0 into an information signal D1 such as a character or an image, and an error in the signal arrangement of the decoded information signal D1 is corrected by the error correction circuit 7 and output as a digital output signal D2. .

  Furthermore, the optimization adjustment of the optimization processing circuit shown in FIG. 1B is performed by first storing an electrical signal obtained by photoelectrically converting optical information read by the optical pickup PU2 as an information signal by the BUFF 9, and then from the BUFF 9 by the control unit 9a. Read as information signal S00, rise adjustment by low frequency waveform adjustment unit 12, adjustment of high frequency gain by boost adjustment unit 11, gain adjustment by gain adjustment unit 10, fall adjustment by LPF band adjustment unit 14, and jitter measurement The device 16 is installed on the output side of the optimization processing circuit 3, and the adjustment amount is increased or decreased at each of the adjustment points A0, A1, A2, and A3 so that each indicates the lowest jitter value. Similarly, the PLL 8 also sets the jitter of the clock F0 to the minimum jitter value by increasing or decreasing the adjustment amount by the adjustment point A4 of the PLL frequency adjusting unit 8a. Each set adjustment amount is stored in a storage unit (not shown) and used for the next operation of the optical disk reproducing apparatus.

  By installing the jitter measuring device 16 on the output side of the optimization processing circuit 3 in this way, the light reception signal of the reflected light of the recording bit obtained by irradiating the recording beam recorded on the optical disk with the light beam is optimized. Therefore, the optimization process to obtain a simple information signal can be easily performed while the optimization processing circuit 3 is incorporated in the optical disk reproducing apparatus.

Next, the optimization process using the jitter measuring device 16 of the optimization processing circuit 3 will be described in detail.
The small size width a0 of the optical disc recording bit shown in FIG. 2A is smaller than the width c in the reflected light shape of FIG. 2B, and the narrow interval b0 of the optical disc recording bit shown in FIG. However, the interval d is smaller in the reflected light shape of FIG.
Therefore, when the reflected light having the reflected light shape shown in FIG. 2B is converted into the electric signal S0, the optical disc recording bit shown in FIG. 2A is small and the optical disc recording bit shown in FIG. 2A is narrow. The level corresponding to the interval b0 is reduced in the PU output signal as the electric signal S0.

  Then, if the portion where the level is reduced is optimized as a reproduction signal by the optimization processing circuit 3 as shown in FIG. 2 (C), the optical disk recording shown in FIG. 2 (A) as shown in FIG. 2 (C). A reproduction shape having a width a1 substantially equal to the width a0 of a small bit size and an interval b1 substantially equal to the narrow interval b0 of the optical disk recording bits shown in FIG. 2A is obtained.

Next, changes in jitter included in the reproduction signal will be described with reference to FIG. Since the interval between the recording bits recorded on the optical disk is arranged to be constant, if the reproduction signal is optimized by the optimization processing circuit 3 as shown in FIG. Since the rising intervals T10, T11, and T12 of the digital playback signal (via A / D5) are all the same, no jitter occurs.
However, in FIG. 3A in which the optimization is not performed, as shown in FIG. 3, a time difference of t00 is generated at the rising portion with a small width and t01 at a narrow width portion with respect to the optimized digital reproduction signal. Therefore, the intervals T00, T01, and T02 are different and cause jitter.
As shown in FIG. 3C, when the optimization process is excessive, a time difference of t20 occurs at the rising portion with a small width and t21 occurs at a narrow width portion with respect to the optimized digital reproduction signal. The intervals T20, T21 and T22 are different and cause jitter.

  As described above, the optimization processing can be easily performed by measuring the jitter of the digital reproduction signal and adjusting the optimization processing circuit 3 so that the jitter becomes the minimum value.

  FIG. 4 is a diagram showing the frequency characteristics of each part of the optimization processing circuit 3. The gain adjustment unit 10 adjusts the signal level in the gain adjustment frequency band of FIG. 4, the boost adjustment unit 11 adjusts the gain in the boost frequency band of FIG. 4, and the low frequency waveform adjustment unit 12 The gain in the frequency band is adjusted, and in each adjustment, the jitter of each digital reproduction signal is measured and set so that the jitter becomes a minimum value.

FIG. 5 shows a case where the rising portion is adjusted by changing the low frequency group delay amount by the low frequency waveform adjustment unit 12 of the optimization processing circuit 3 and a high frequency group delay amount by the LPF band adjustment unit 14 is changed. The case where the falling part is adjusted by doing is shown.
In this way, jitter adjustment can be facilitated by individually controlling the rising and falling portions.

FIG. 6 is a flowchart of optimization processing at the time of process adjustment of the optical disk reproducing apparatus. By performing each jitter adjustment twice, the adjustment can be performed satisfactorily.
FIG. 7 shows an optimization process flowchart during set adjustment. Jitter is measured by setting a threshold value, and if it is within the threshold value, the optimization process adjustment ends at that point, so the adjustment is simpler. It will be a thing.

  As described above, according to the optical disk reproducing apparatus according to the embodiment of the present invention, the light receiving signal of the reflected light of the recording bit obtained by irradiating the recording bit recorded on the optical disk with the light beam is optimal. The optimization processing can be easily performed while the optimization processing circuit for the information signal is incorporated in the optical disc reproducing apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram for explaining an optical disc reproducing apparatus using an optimization processing circuit according to an embodiment of the present invention, (A) is a diagram showing a configuration of an optical disc reproducing apparatus, and (B) is an optimum one. It is a figure for demonstrating the structure and adjustment method of an optimization processing circuit. It is a figure which shows the some recording bit currently recorded on the data area of an optical disk, (A) is a figure which shows the shape of the some recording bit currently recorded on the data area of an optical disk, (B) is an optical disk It is a figure which shows the reflected light shape and PU output signal on PU reflected by irradiating the light beam to the several recording bit currently recorded on the data area | region, (C) is PU output by an optimization process circuit It is a figure which shows the reproduction | regeneration signal and reproduction | regeneration shape in which the signal was optimized. The figure which converted the electric signal into the digital signal is shown, (A) shows the figure which converted the PU output signal into the digital output signal, and (B) shows the optimally processed reproduction signal converted into the digital output signal. FIG. 6C shows a diagram in which an excessive reproduction signal subjected to excessive optimization processing is converted into a digital output signal. It is a figure which shows the frequency characteristic of each adjustment part of an optimization process circuit. It is a figure which shows the correction state of a reproduction | regeneration signal, (A) is a figure which shows the correction state of a rising edge, (B) is a figure which shows the correction state of a falling edge. It is a figure which shows the flowchart which adjusts an optimization process circuit in process adjustment. It is a figure which shows the flowchart which adjusts an optimization process circuit in set adjustment. It is a figure which shows the block diagram for demonstrating the conventional optical disk reproducing device using an optimization processing circuit, (A) is a figure which shows the structure of an optical disk reproducing device, (B) is a structure of an optimization processing circuit It is a figure for demonstrating the adjustment method. It is a figure which shows the frequency characteristic of an optimization process circuit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Optical disk, 2 ... PU, 3 ... Optimization processing circuit (reproducing part), 4 ... AGC, 5 ... A / D, 6 ... Decoding circuit, 7 ... Error correction circuit, 8 ... PLL (reference frequency setting unit), 9 ... BUFF, 9a ... control unit, 10 ... gain adjustment unit, 11 ... boost adjustment unit, 12 ... low Band waveform adjustment unit, 13... Addition unit, 14... LPF band adjustment unit, 15... Noise removal unit, 16.

Claims (1)

In an optical disc playback apparatus having a playback section for reading a plurality of recording bits recorded in a data area of an optical disc and playing back information,
The playback unit
An optical pickup that reads a plurality of recording bits recorded in the data area of the optical disc as optical information;
A buffer unit that stores an electrical signal obtained by photoelectrically converting optical information read by the optical pickup as the information signal;
A control unit for reading out the information signal from the buffer unit;
A response characteristic adjusting unit that adjusts a response characteristic of the information signal read by the control unit;
A boost adjustment unit for amplifying a high frequency region of the information signal read by the control unit;
A gain adjusting unit for adjusting a gain in a low frequency region of the information signal read by the control unit;
An adder for adding the response signal, the information signal in which the high frequency region is amplified, and the information signal in which the gain in the low frequency region is adjusted;
An optical disc reproducing apparatus comprising:

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