JP3362431B2 - CD player access method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for accessing a CD player, and more particularly to a method for accessing a CD player capable of performing focusing efficiently. 2. Description of the Related Art On a compact disk (hereinafter abbreviated as CD), a plurality of music programs are sequentially recorded spirally on a plurality of tracks, and a lead-in area on the innermost circumference has a Information (TOC) such as the number of music pieces and playing time on the CD is recorded. Also, information on the currently reproduced position, such as the number of the song, the time from the start of the song, and the time from the beginning of the recording unit (subcode:
SUBQ) is recorded in the track of the music signal. A conventional CD player includes an optical head for reading information from a CD via a laser beam, a translation driving means for moving the optical head in a direction parallel to the CD, and a moving means for moving the optical head in a direction perpendicular to the CD. A vertical drive unit for rotating the CD, a rotary drive unit for rotating the CD, an amplifier for amplifying a signal read by the optical head, a digital signal processing circuit for converting an analog signal from the amplifier into a digital signal, and a digital signal processing circuit. Control means for checking the focusing on the basis of the above signal and controlling each driving means. A focusing operation at the time of starting reproduction of a CD player will be described with reference to a flowchart of FIG. [0005] The control means controls the translation drive means to move the optical head to the innermost circumference of the CD (step S1 in FIG. 6). [0006] Further, the control means is that the optical head is a CD.
The optical head is moved outward by a fixed amount by controlling the parallel movement driving means so as to be positioned at the reflection portion (step S2 in FIG. 6). [0007] The optical head irradiates the CD with laser light and outputs reflected light from the CD surface to a digital signal processing circuit. [0008] The digital signal processing circuit converts an analog signal from the optical head into a digital signal and outputs the digital signal to the control means. [0009] The control means controls the vertical movement driving means based on the signal level from the digital signal processing circuit to perform focusing (step S3 in FIG. 6). [0010] The control means checks whether the focusing has been successful (step S4 in FIG. 6). [0011] If the focusing is successful, the control means shifts to a disk playing process for playing music (step S5 in FIG. 6). However, if the focusing fails, the number of failures is checked (step S6 in FIG. 6), and if the number is less than a preset number, the focusing is retried. On the other hand, when the number of failures reaches a preset number, the operation is stopped (step S in FIG. 6).
7). Next, the operation when the optical head jumps due to vibration or the like during the reproducing process will be described with reference to the flowchart of FIG. [0015] The control means checks the flying of the optical head (step S1 in FIG. 7). [0016] When the control unit detects the jump of the optical head, it controls the vertical movement driving unit based on the signal level from the digital signal processing circuit to perform focusing (step S2 in FIG. 7). [0017] The control means checks whether the focusing has been successful (step S3 in FIG. 7). [0018] If the focusing is successful, the control means continues disc play (step S in FIG. 7).
4). However, if the focusing fails, the number of failures is checked (step S5 in FIG. 7), and if the number is less than a preset number, the focusing is retried. On the other hand, when the number of failures reaches a preset number, the reproduction process is stopped (step S6 in FIG. 7). However, in the above-mentioned conventional example, since the focusing process at the time of starting reproduction is performed only at one position, there is a flaw or the like at that position, If the camera cannot move to the reflection portion, it fails even after performing the focusing a specified number of times, and there is a disadvantage that the reproduction process cannot be performed. Also, the focusing process when the head jumps,
Since the operation is performed only at one jump destination, if the position is a non-reflection position or if there is a flaw or the like at the position, even if the focusing operation is performed a specified number of times, a failure occurs and the reproduction process cannot be performed. there were. It is an object of the present invention to provide a method for accessing a CD player which can solve the disadvantages of the prior art and in particular can automatically perform focusing at a place where laser light is normally reflected. Is to do. According to the present invention, a first access step for focusing a laser beam on a CD at a current position of an optical head, and the optical head is moved to the CD by a predetermined distance. A second access step moving in parallel;
A third access step for focusing the laser beam at the position set by the second access step ;
And a fourth access step of moving the optical head from the innermost position to the reflection portion that is a fixed amount outside . Then, if the focusing in the first access step is unsuccessful ,
Within a preset number of times until the point matching is successful
The second and third access steps are repeatedly executed, and the second and third access steps are repeated a predetermined number of times.
If the focusing is unsuccessful even after several repetitions , the focusing is successful again after executing the fourth access step.
The second or third number within a preset number of times
, Etc. are repeatedly executed. This aims to achieve the above-mentioned object. In the first access step, the laser beam is focused on the CD at the current position of the optical head. For example, focusing of laser light is performed at the current position of the optical head based on the output level of the optical head. In the second access step, the optical head is moved parallel to the CD by a predetermined distance. For example,
If the focusing is unsuccessful in the first access step, the optical head is moved parallel to the CD by a preset distance. In the third access step, the laser beam is focused at the position set in the second access step. For example, based on the output level of the optical head, the laser light is focused at the set position of the optical head in the second access step. In the fourth access step, the innermost circumference of the CD
The optical head is moved to a reflective portion that is a fixed amount outside from the position . That is , the optical head is moved to the innermost circumference of the CD, and the optical head is further moved outward by a fixed amount so as to be located at the reflection portion of the CD. This fourth access step includes the first access step.
Even if the second and third access steps are repeatedly executed a preset number of times when the focusing in the access step is unsuccessful, the second and third access steps are executed when the focusing is unsuccessful. After executing the fourth access step, the second to third access steps are repeatedly executed a predetermined number of times. Therefore, in the case where the focusing is unsuccessful, the optical head is temporarily moved to the reference position before the second access step. Instead, focusing can be performed at the head position on the reflection portion. An embodiment of the present invention will be described below with reference to FIGS. The embodiment shown in FIGS. 1 to 4 is a first access step for focusing the laser beam 6 on the CD 5 at the current position of the optical head 4 and the optical head 4 is moved to the CD 5 by a predetermined distance. A second access step that moves in parallel, a third access step that focuses the laser beam 6 at a position set by the second access step, and a certain amount from the innermost peripheral position of the CD 5
And a fourth access step of moving the optical head 4 to the side reflection portion . If the focusing in the first access step is unsuccessful, the second or third access step is repeatedly executed a predetermined number of times. If the focusing is unsuccessful, After the fourth access step is executed, the second to third access steps are repeatedly executed a preset number of times. More specifically, the embodiment shown in FIG. 1 includes an optical head 4 for reading information from a CD 5 by using a laser beam 6 as a medium, a thread feed motor 1 for moving the optical head 4 in parallel with the CD 5, and an optical head. A vertical drive 2 for moving the head 4 vertically to the CD 5, a spindle motor 3 for rotating the CD 5, an RF amplifier 7 for amplifying a signal read by the optical head 4, and a digital signal for converting an analog signal from the RF amplifier 7 A digital signal processing circuit 8 for converting the optical head 4 into a focusing signal based on a signal from the digital signal processing circuit 8;
Microcomputer 9 for calculating position control data
And a servo controller 10 for controlling the sled feed motor 1, the vertical drive 2, and the spindle motor 3 based on signals from the microcomputer 9. Next, in this embodiment, the focusing operation at the start of reproduction of a CD will be described with reference to the flowchart of FIG. [0033] The microcomputer 9 controls the thread feed motor 1 via the servo controller 10 to move the optical head 4 to the innermost circumference of the CD 5 (FIG. 2).
Step S1). [0034] The microcomputer 9 controls the thread feed motor 1 via the servo controller 10 to move the optical head 4 outward by a fixed amount so that the optical head 4 is positioned at the reflection portion of the CD 5 as shown in FIG. (Step S2 in FIG. 2). [0035] The optical head 4 converts the laser beam 6 to a CD5
And outputs the reflected light from the surface of the CD 5 to the RF amplifier 7. [0036] The RF amplifier 7 amplifies the signal from the optical head 4 and outputs the signal to the digital signal processing circuit 8. [0037] The digital signal processing circuit 8 converts an analog signal from the RF amplifier 7 into a digital signal and outputs the digital signal to the microcomputer 9. [0038] The microcomputer 9 controls the vertical movement driving means 2 via the servo controller 10 based on the signal level from the digital signal processing circuit 8 (Step S3 in FIG. 2). That is, the optical head 4 is moved perpendicularly to the CD 5 so that the signal level from the digital signal processing circuit 8 becomes maximum. [0039] The microcomputer 9 checks whether the focusing has been successful based on the signal level from the digital signal processing circuit 8 (Step S4 in FIG. 2). That is, if the maximum value of the signal level from the digital signal processing circuit 8 is equal to or greater than a preset value, it is determined that the focusing has been successful. [0040] When the focusing is successful, the microcomputer 9 shifts to a disc play, that is, a music reproduction process (step S5 in FIG. 2). On the other hand, if focusing fails, the microcomputer 9 controls the sled feed motor 1 via the servo controller 10 to avoid scratches and the like, and moves the optical head 4 outward by several mm (FIG. 2). Step S6). [0042] The microcomputer 9 checks the number of failed focusing operations (step S7 in FIG. 2), and if the number of failed focusing operations is within a preset number, retry the focusing. On the other hand, if the number of failures has reached the preset number, the microcomputer 9 stops its operation (step S8 in FIG. 2). Next, in this embodiment, the focusing operation when the optical head 4 jumps due to vibration or the like during music reproduction will be described with reference to the flowchart of FIG. [0045] The microcomputer 9 checks the flying of the optical head 4 (step S1 in FIG. 3). That is, the signal level from the digital signal processing circuit 8 is
When the value becomes equal to or less than a preset value, it is determined that the optical head 4 has jumped. [0046] When the microcomputer 9 detects the jump of the optical head 4, the microcomputer 9 controls the vertical movement driving means 2 via the servo controller 10 to perform focusing (step S2 in FIG. 3). [0047] The microcomputer 9 checks whether the focusing has been successful based on the signal level from the digital signal processing circuit 8 (Step S3 in FIG. 3). That is, if the maximum value of the signal level from the digital signal processing circuit 8 is equal to or greater than a preset value, it is determined that the focusing has been successful. [0048] When the focusing is successful, the microcomputer 9 continues the disc play, that is, the music reproduction process (step S4 in FIG. 3). [0049] If the focusing fails, the microcomputer 9 controls the sled feed motor 1 via the servo controller 10 to avoid scratches and the like, and moves the optical head 4 outward by several mm (step S in FIG. 3).
5). [0050] Subsequently, the microcomputer 9 checks the number of failed focusing operations (step S in FIG. 3).
6) If the number of times is within the preset number, retry focusing. On the other hand, if the number of failures has reached the preset number, it is checked whether or not the focusing processing is the first place (step S in FIG. 3).
7). [0052] If the focusing process is not the first position, the microcomputer 9 stops the operation (step S8 in FIG. 3). On the other hand, if the focusing process is the first position, the microcomputer 9 controls the thread feed motor 1 via the servo controller 10 to move the optical head 4 to the innermost circumference (FIG. 3). Step S9). Further, the microcomputer 9 controls the sled feed motor 1 via the servo controller 10 so that the optical head 4 is positioned at the reflection portion of the CD 5.
Is moved outward by a fixed amount (step S10 in FIG. 3), and focusing is performed again. As described above, when the optical head 4 is located within the reflection portion of the CD 5 but abnormal reflection occurs due to a flaw or the like and focusing cannot be performed, the optical head 4 is slightly moved parallel to the CD 5. Move and refocus. When the optical head 4 is located at the non-reflection portion M where the laser beam 6 is not reflected and returns as shown in FIGS. 4 and 5, the optical head 4 is moved to the reference position. And focus again. In this case, access to the CD player is performed in the following procedure. That is, at the current position of the optical head 4, the CD 5
A first access step of focusing the laser light 6 on the optical head 6, and moving the optical head 6 by a predetermined distance to the CD 5.
A second access step of moving parallel to a third access step of performing focusing of the laser beam 6 at a position set by the second access process, the innermost position of the CD5
And a fourth access step of moving the optical head 4 to the reflection portion that is a fixed amount outside from the position. And if the focusing in the first access step is unsuccessful ,
Until the set succeeds, the second
With repeats the stone third access step, the
Repeat the second to third access steps a preset number of times
If the focusing is unsuccessful even after the reverse execution , the fourth access step is performed and the focusing is successful again.
Within the range of the preset number of times,
Process is repeated. Therefore, the position S where the laser light is reflected normally
, And the reproduction of the CD is performed smoothly. Further, even if a CD having a flaw is reproduced, it is very unlikely that the reproduction cannot be performed due to a failure in focusing, so that the operation of the system becomes easy and the optical head flies to a portion where the laser light is not reflected by a large vibration. Even if it does, it can recover, and the recovery performance against vibration improves. Since the present invention is constructed and functions as described above, according to the present invention, it is possible to automatically perform focusing at a place where laser light is normally reflected. Even when reproducing a CD, or when the head jumps to a portion where laser light is not normally reflected due to large vibration during reproduction, it is possible to perform reproduction of a CD smoothly, which is an unprecedented advantage. A CD player access method can be provided. Moreover, if the focusing is unsuccessful, the optical head is moved by a preset distance.
Since the optical head is moved to the reference position once before moving in parallel with the CD , even if the optical head moves to the non-reflective part by repeating retry, the disk is focused on the head position on the reflective part without stopping the disk. Can be matched.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a configuration diagram showing one embodiment of the present invention. FIG. 2 is a flowchart for explaining the operation of the embodiment shown in FIG. 1; FIG. 3 is a flowchart for explaining another operation of the embodiment shown in FIG. 1; FIG. 4 is a schematic plan view of the CD shown in FIG. FIG. 5 is a schematic sectional view taken along line AA of FIG. 4; FIG. 6 is a flowchart showing the operation of the conventional example. FIG. 7 is a flowchart showing another operation of the conventional example. [Description of Signs] 3 Spindle motor 4 Optical head 5 Compact disk (CD) 6 Laser beam 7 RF amplifier (high frequency amplifier) 8 Digital signal processing circuit 9 Microcomputer 10 Servo controller

Claims (1)

(57) [Claim 1] A first access step for focusing a laser beam on a compact disc at a current position of an optical head, and the compact disc is moved by a predetermined distance from the compact disc. A second access step of moving the laser beam in parallel with the second access step, and a third access step of performing focusing of the laser beam at a position set by the second access step.
A certain amount of reflection from the innermost position of the compact disc
And a fourth access step of moving the optical head to a portion. If the focusing in the first access step is unsuccessful, a predetermined number of times until the focusing is successful.
The second and third access steps are repeatedly executed within the box, and the second and third access steps are repeated a predetermined number of times.
If even a few repeatedly executed focusing is unsuccessful, again focusing later executing the fourth access steps
Until succeeding, the second number is set within a preset number of times.
A method for accessing a CD player, comprising repeatedly executing a third access step .