JPH04245061A - Optical disk reproducing device - Google Patents

Abstract

PURPOSE:To control the gain of the rotation servo of a spindle motor by discriminating the magnitude of the diameter of a compact disk even when the compact disk is rotationally driven. CONSTITUTION:The gain of a gain amplifier 15 in the route of the rotation servo 14 of a spindle motor 3 is controlled through a control circuit by detecting total recording time in the index information (TOC) of a compact disk 1 or 2.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disc reproducing apparatus, and is particularly suitable for application to an optical disc reproducing apparatus that reproduces a plurality of types of optical discs of different sizes.

0002

2. Description of the Related Art Various types of conventional optical discs, particularly compact discs (hereinafter referred to as CDs), have been proposed. Its diameter is 120 mm, which is used in CD digital audio systems, and its linear velocity is 1.2.
~1.4 meters/sec CLV (constant L
inner velocity) method is the standard.

[0003] Recently, the diameter size is 80 mm and the playing time is 2.
CLV format CD singles with a length of approximately 0 minutes are also available on the market.

[0004] In such an optical disc playback device for driving a plurality of different types of CDs, a spindle motor that drives the CD is rotated based on a phase comparison signal between a clock signal separated from a CD playback signal and a predetermined reference signal. PLL (Phase Locked Loop) in servo system path
The servo gain of this PLL control is automatically switched according to CDs with different diameters.

For this reason, it becomes necessary to detect the size (diameter) of a CD placed on a spindle hub driven by a spindle motor.

[0006] The most common detection method for determining this diameter is optical or mechanical detection, but since CD single discs use an adapter, it is difficult to remove optically and mechanically, resulting in false detection. There were many problems.

[0007] In order to solve such problems, the applicant of the present invention, in Japanese Patent Application Laid-Open No. 2-216663, detected the startup response state of the spindle motor, and based on the result, the C
We proposed an optical disc playback device that detects the type of D.

To explain the outline of the operation shown in the above publication, the spindle motor that drives the spindle hub on which the CD is placed and rotated has a frequency generator, and the spindle motor drives the spindle hub on which the CD is placed and rotates. An output signal proportional to the speed is taken out, and the spindle motor is driven by a reference starting signal, but at that time, a PLL servo is applied, which is driven by a comparison signal between the reference starting signal and a frequency generator. There is.

That is, when the reference activation signal is supplied, the
As shown in A, the voltage is raised to the reference activation signal voltage VREF. Therefore, the rotational speed of the spindle motor gradually increases as the reference starting signal voltage VREF rises.

[0010] In such a spindle motor, the starting response state changes depending on the type of CD.
Since a CD with a diameter of 80 mm is heavier than a CD with a diameter of 80 mm, the activation response state is delayed.

Therefore, when driving a CD with a diameter of 80 mm, the output signal V of the frequency generator is as shown in FIG. 6B.
While F rises to a constant voltage in a short time, 12
When driving a normal CD of 0 mm Φ, the output signal VF of the frequency generator rises in a longer time than for a CD of 80 mm Φ, as shown in FIG. 6C.

[0012] Therefore, this rise time t0 to t
By counting the time from 11 and t0 to t12 using a predetermined clock, it is possible to determine whether it is a standard CD disc or a CD single disc.

[0013]

[Problems to be Solved by the Invention] According to the above-described configuration, a device that does not particularly require an optical or mechanical detection mechanism can be obtained. ), in order to reduce battery consumption, a kick pulse is supplied to the spindle motor to rotate the CD and perform focus retraction, etc.

That is, the focus is pulled in using the inertia of the rotation system including the spindle motor and the CD, and after the focus is pulled in, the spindle servo is being carried out.

[0015] Therefore, when measuring the time from when the spindle motor is stopped to when the number of revolutions reaches the normal speed, there is no reference stopped state, so there is a problem in that the CD size cannot be determined.

The present invention has been made to solve the above-mentioned problems, and its purpose is to provide an optical disc playback device that can determine the size of a CD even when the spindle motor is rotating. It is in.

[0017]

Means for Solving the Problems The optical disc reproducing apparatus of the present invention, as shown in FIG. An extraction means 12 for extracting the table of contents information recorded on the inner periphery of the recording area of the optical discs 1 and 2, and a disk size for determining whether the total recording time in the table of contents information extracted by the extraction means 12 is within a predetermined time. The apparatus is equipped with a control means 11 that controls the motor 3 that rotates the optical disk using the determination means 13.

[0018]

[Operation] According to the optical disc reproducing apparatus of the present invention, the table of contents information (Ta
ble of contents: hereinafter referred to as TOC)
is read out, the difference in diameter of the optical disc is determined, and the rotational servo gain is controlled, so the type of optical disc can be determined even while the optical disc is rotating.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The optical disk reproducing apparatus of the present invention will be described in detail below with reference to FIGS. 1 to 5.

FIG. 1 is a system diagram showing an embodiment of the optical disc reproducing apparatus of the present invention. In the figure, 1 is a CD single disc with a diameter of 80 mm (hereinafter referred to as a single CD) placed on a spindle hub rotated by a spindle motor 3. 2 is a CD standard disc with a diameter of 120 mm (hereinafter referred to as a single CD). (hereinafter referred to as standard CD).

Reference numeral 4 denotes an optical pickup which has a two-axis actuator structure and includes a focus servo and a tracking servo actuator.

The optical pickup 4 is moved by a pickup feed motor 6 along a drive screw 5 in the radial direction of the CD 1 or 2 to extract data from the pits recorded on the CD and reproduce music.

The output signal taken out from the optical pickup 4 is supplied to a signal processing circuit 9. This circuit includes a low-pass filter (LPF), a crystal oscillator, a decoder, etc., and left and right audio output signals are taken out via a digital-to-analog conversion circuit (D/A) 10.

The output from the signal processing circuit 9 is further supplied to a control circuit 11.

Furthermore, the output of the optical pickup 4 is supplied to an error signal forming circuit 7 and a TOC extracting circuit 12.

The error signal forming circuit 7 detects the tracking error signal and the focus error signal, and feeds them back to the tracking and focus actuator of the optical pickup 4 via the servo circuit 8, thereby performing focus and tracking servo.

[0027] Also, the TOC extracted by the TOC extraction circuit 12
C is supplied to a discrimination circuit 13 that discriminates whether it is a single CD or a standard CD, and the discrimination result is supplied to a control circuit 11.

The output of the control circuit 11 controls the optical pickup feeding motor 6 and also controls the gain of the spindle motor 3 through the rotation servo circuit 14 with the gain amplifier 15 .

That is, based on the TOC determination result, the gain of the gain amplifier 15 is set to match the CD for 80 mm Φ or the CD for 120 mm Φ.

[0030] Below, the above-mentioned single CD1 and standard C
The TOC recorded in D2 will be explained using FIGS. 2 to 4.

FIG. 2 shows the format of the sub-coding frame, and data are recorded in the form of pits on a CD frame by frame. This one frame has a frame synchronization signal of 24 bits, and one subcoding symbol = 14
Consists of 32 symbols x 14 bits, data and parity, and a frame synchronization signal of 24 bits.
It is regarded as one symbol, and three bits for combining these symbols are used as a link, and it is composed of 588 channel bits.

[0032] In the above sub-coding, there are 98 frames of 1-byte additional information containing information other than music.
Each bit is treated as a P, Q, R, S, T, U, V and W channel, and currently only P and Q of these bits
channels are used. The P channel is used for cueing, and there are synchronization frames called S0 and S1 in the first and second frames of subcoding. This is used for accessing P1 to P96 and Q1 to Q96.

[0033] The contents of the Q channel are So and S1 mentioned above.
After the 2 bits, as shown in Figure 3, there are 4 control bits that identify the number of audio channels, etc., and 4 bits that indicate the address. Address = 0001 (mode 1)
The mode of has primary meaning.

After the 4 bits of the address are 72 bits of data, and the next 16 bits are a CRC for detecting errors in the cyclic code.

The data structure of the lead-in track of 72 bits of data (track number TNO=00), ie, TOC, in the case of mode 1 with the address=0001 described above is configured as shown in FIG.

In FIG. 4, the first 8 bits are the track number (T
00 indicates a lead-in portion. The next 8-bit index (POINT) is a TNO index and is expressed by two BCD digits, but it does not exist in the lead-in track, and the 8-bit index of this part and the part after all 8 bits are zero, A table of contents, ie, TOC, is written in each 8 bits of seconds and frames. The lead-in portion of TNO=00 is continuously and repeatedly recorded.

[0037] The contents of the TOC are the time code values at which the songs start in order for all songs on the CD,
The numbers of the first and last songs on the CD, the absolute time until the songs are completed, etc. are recorded.

In FIG. 4, the 8 bits of minutes, seconds, and frames after the 8 bits of the index indicate the running time of the song.

In the present invention, the size of the CD is determined by reading the TOC recorded on the CD 1 or 2, and the servo gain of the spindle motor 3 is controlled based on the result. This is shown in Figure 5.
The operation will be explained using the flowchart.

In a portable small optical disc playback device, before applying the focus servo, a kick pulse is supplied to the spindle motor 3 in order to enjoy long-time music playback with a limited battery. A rotating system including a single CD 1 and a standard CD 2 is rotated using inertia. In this state, the spindle motor 3 is started as shown in the first step ST1 in FIG.

Next, the control circuit 11 controls the optical pickup moving motor 6 to move the optical pickup 4 along the drive screw 5, and in the case of a standard CD 2, it moves the optical pickup 4 to the lead position at the innermost circumference of the disc, which is 23 mm from the center position of the spindle. Bring it to the in position (TOC position) (second step ST2
)

Here, a focus error or the like is detected by the error signal forming circuit 7 based on the output data from the optical pickup 4 and sent to the optical pickup 4 via the servo circuit 8.
Focus pull-in, etc. are performed (third step ST3
)

In the next fourth step ST4, the TOC signal recorded in the lead-in is sent to the TOC signal via the optical pickup 4.
The TOC is supplied to the OC extraction circuit 12 and the TOC is extracted.

[0044] In the next step ST5, the absolute time until the music recorded in the TOC is completed is detected, and it is determined whether the total recorded time is 22 minutes or more.

Specifically, the maximum recording capacity of a single CD with a diameter of 80 mm Φ is approximately 22 minutes in total playing time, so if the TOC is within this time, a single CD with a diameter of 80 mm Φ
It can be determined that it is D1.

Therefore, if the TOC recording time is 22 minutes or more in the fifth step ST5, the process advances to the sixth step ST6, and the control circuit 11 controls the rotation servo circuit 14 by supplying the determination result to the control circuit 11. The anti-rolling property of the spindle motor 3 rotating at the CLV is improved by increasing the gain of the gain amplifier 15 via the CLV.

If NO in the fifth step ST5, the seventh step ST5
It is sufficient to proceed to step ST7 and perform gain control for CD single 1 drive.
After steps ST6 and ST7 are completed, the process reaches the end.

Since the optical disc reproducing apparatus of the present invention operates as described above, it is not only possible to distinguish between a single CD and a standard CD even when focusing while rotating the spindle, but also to distinguish between a single CD and a standard CD. Compared to the method in which CDs of different sizes are determined by counting the rise time of the spindle, this method does not cause problems such as changes in the count time due to increases in the temperature of the spindle motor.

Furthermore, for devices that require anti-rolling properties such as portable optical disc playback devices, a diameter of 120 mm is required.
The amplifier gain that is insufficient when driving standard CD2 is TO
It is possible to obtain a product with improved anti-rolling properties by controlling C reading simultaneously.

[0050] In the above embodiment, a portable optical disc reproducing device was explained, but it is not limited to this, and the application is applicable not only to standard CDs but also to CDs with pictures recorded with TOC, etc. It is obvious that it can be done.

[0051]

[Effects of the Invention] According to the optical disc playback device of the present invention,
It is possible to obtain a device that can perform servo gain control of the spindle motor by determining the size of the CD diameter even when the spindle motor is rotating.

[Brief explanation of the drawing]

FIG. 1 is a system diagram of an optical disc reproducing apparatus of the present invention.

FIG. 2 is a diagram showing the format of a subcode frame used in the optical disc playback device of the present invention.

FIG. 3 is an explanatory diagram showing a frame structure of a Q channel used in the optical disc reproducing apparatus of the present invention.

[Figure 4] TOC used in the optical disc playback device of the present invention
It is an explanatory diagram showing the data structure inside.

FIG. 5 is a flowchart of the optical disc playback device of the present invention.

FIG. 6 is a signal waveform diagram showing a conventional CD size detection method.

[Explanation of symbols]

1 CD single disc 2 CD standard disc 3 Spindle motor 4 Optical pickup 11 Control circuit 12 TOC extraction circuit 13 80 mm Φ/120 mm Φ CD discrimination circuit 15
gain amplifier

Claims (1)

[Claims] 1. An optical disc reproducing device capable of reproducing a plurality of types of optical discs, comprising: extracting means for extracting table of contents information recorded on the inner periphery of a recording area of the optical disc; and a table of contents information extracted by the extracting means. An optical disc reproducing apparatus comprising: a control means for controlling a motor for rotationally driving the optical disc by means of a disc size determining means for determining whether the total recording time in the table of contents information is within a predetermined time.