JP2003296945A - Optical disk drive - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the reliability of access by realizing the stable focus jump in a recordable multi-layer optical disk having two or more laminated information surfaces including a double-layer optical disk. <P>SOLUTION: This optical disk drive carried out the focus jump operation by using an output signal of a photodetector, by which the quantity of reflected light beam from an information carrier is detectable. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk device for optically recording or reproducing information, and in particular, interlayer movement (hereinafter, focus) of a multi-layered information carrier (hereinafter, referred to as an optical disk) having information surfaces laminated. The present invention relates to an optical disk device that performs a moving operation while detecting a plurality of types of signals when performing a "jump".

[0002]

2. Description of the Related Art In a conventional optical disk device, when a focus control state in which a light beam is focused on an information surface of a multi-layer optical disk having a plurality of information surfaces is moved from a focus control state to another information surface at a high speed. , The focus control is temporarily disabled, and the condenser lens is accelerated / decelerated in the focus direction based on the level of the amount of light reflected from each information surface and the pull-in level set on each information surface to move to another information surface. Go, do a focus jump. This is described in, for example, Japanese Patent Laid-Open No. 9-326123.

A conventional optical disk device will be described with reference to FIG. In FIG. 21, the moving means is the focus actuator 6, the convergence state detecting means is the focus error generator 9 (hereinafter referred to as FE generator 9), the focus control means is the focus control filter 10 (hereinafter referred to as Fc filter 10), the focus. The jump means is a jump pulse generator 12 and a jump command device 13.

A semiconductor laser 3, a condenser lens 5, a polarization beam splitter 4, a focus actuator 6 (hereinafter referred to as Fc actuator 6), and a photodetector 8 are attached to the optical head 2. The light beam generated by the semiconductor laser 3 passes through the polarization beam splitter 4 and is converged on the disc-shaped optical disc 1 by the condenser lens 5. The reflected light beam then passes through the condenser lens 5 again, is reflected by the polarization beam splitter 4, and is applied to the photodetector 8. The condenser lens 5 is supported by an elastic body (not shown), and when an electric current is passed through the Fc actuator 6, the condenser lens 5 moves in the focus direction by an electromagnetic force.

The photodetector 8 sends the detected light amount signal to the FE generator 9. The FE generator 9 uses the light amount signal of the photodetector 8 to respond to an error signal indicating the convergence state of the light beam on the information surface of the optical disc 1, that is, the position shift of the focus of the light beam with respect to the information surface of the optical disc 1. Error signal (hereinafter,
(Referred to as an FE signal) to stabilize the focus control, the Fc filter 10 and the selector 1 that perform phase compensation.
4 and the focus driver 11 (hereinafter, Fc driver 11
Is called) to the Fc actuator 6. The Fc actuator 6 drives the condenser lens 5 in the focus direction so that the light beam converges on a certain information surface of the optical disc 1 in a predetermined state. This is focus control.
The photodetector 8 sends a light amount signal to the FE generator 9 using the light beam reflected by the polarization beam splitter 4.

The FE generator 9 sends the FE signal to the Fc filter 10, the jump pulse generator 12 and the jump commander 13 by using the light amount signal of the photodetector 8. Fc filter 1
0 uses the FE signal of the FE generator 9 to send a focus drive signal for focus control to the selector 14. The jump command device 13 sends a low-level jump operation signal to the jump pulse generator 12 and the selector 14 in the initial state, and sends a high-level jump operation signal to the jump pulse generator 12 and the selector 14 after the focus jump start timing. Further, after receiving the FE signal of the predetermined condition from the FE generator 9, the low-level jump operation signal is sent to the jump pulse generator 12 and the selector 14. The jump pulse generator 12 receives FE while receiving a high-level jump operation signal from the jump command device 13.
A jump pulse signal is sent to the selector 14 according to the value of the signal.

When the selector 14 receives the low-level jump operation signal from the jump command device 13, it sends the focus drive signal sent from the Fc filter 10 to the Fc driver 11, and the jump command device 13 outputs the high-level jump operation signal. When receiving the jump pulse generator 31
The jump pulse signal sent from the Fc driver 1
Send to 1. The Fc driver 11 sends the actuator drive signal sent from the selector 14 to the Fc actuator 6. The Fc actuator 6 performs focus control and focus jump by driving the condenser lens 5 in the focus drive direction based on the drive signal of the Fc driver 11.

The focus jump in this conventional example will be described with reference to FIG. 22 by taking a dual-layer disc having two information surfaces as an example. The waveform a shows the FE signal from the FE generator 9, the waveform b shows the actuator drive signal from the Fc driver 11, and the waveform c shows the jump operation signal from the jump command unit 13. At time t50, the jump command device 13 sends a high-level jump operation signal to the selector 14 to start the focus jump, and at time t53.
From the point of time, the jump command unit 13 sends a low-level jump operation signal to the selector 14 to indicate that the focus jump has ended, and the focus control operation section before time t50 and after time t53 is from time t50 to time t5.
Sections up to 3 indicate focus jump control operation sections.

At time t51 in the focus jump control operation section, at time t52, the jump pulse generator 12 detects that the level of the FE signal exceeds s51 from bottom to top and ends the acceleration operation. Indicates that the jump pulse generator 12 has detected that the level of the FE signal has exceeded s52 from above to below and has started deceleration operation. Of the focus jump control section, the section from time t50 to time t51 is the acceleration pulse output section, time t5.
The section from 1 to time t52 is called a deceleration start waiting section, and the section from time t52 to time t53 is called a deceleration pulse output section. Among these, in the deceleration start waiting section, the Fc driver 11 sends a zero level signal to the Fc actuator 6. In this way, the focus jump is realized by outputting the acceleration / deceleration pulse with the level of the FE signal as the output condition.

[0010]

As described above, the length of the deceleration start waiting section depends on the variation in the interlayer distance of the optical disc 1 to be controlled. When the interlayer distance of the optical disc 1 to be controlled becomes long, the deceleration start waiting section in which open control that cannot cope with disturbance is performed becomes long and the focus jump becomes unstable.

FE is set as the output condition of the acceleration / deceleration pulse.
Since the signal is used, the acceleration / deceleration pulse can be output only within the detection range of the FE signal. Therefore, when the FE signal detection range is narrow, it may not be possible to obtain a sufficient acceleration / deceleration output time for moving to the target information surface. Also, when the detection range of the FE signal becomes narrow, the deceleration start waiting section occupies most of the jump operation, and during the deceleration start waiting, the focus jumps by returning to the information surface that was the focus control target at the start of the jump. Becomes unstable.

The present invention has been made to solve the above problems, and realizes stable focus jump in a recordable multi-layer optical disc having two or more laminated information surfaces including a double-layer optical disc. , Aims to improve the reliability of access.

[0013]

In an optical disk device according to the present invention, a convergence point of a light beam converged on an information carrier having a plurality of stacked information surfaces is moved in a direction substantially perpendicular to the information surfaces. Moving means, a convergent state detecting means for generating a signal according to the convergent state of the light beam on the information carrier, and driving the moving means according to a focus error signal which is an output signal from the convergent state detecting means. Focus control means for controlling the convergence state of the light beam on the information carrier to be substantially constant, and a predetermined signal is output to the focus control means and a signal is output to the moving means to converge the light beam. Focus jump means for moving a point from any information surface of the information carrier to another information surface, and stray light measuring means for measuring the amount of reflected light from the information surface adjacent to the information surface on which the light beam is converged Depending on the result of the stray light measuring means,
A jump signal output setting means for setting a signal output of the focus jump means is provided.

The jump signal output setting means of the optical disk apparatus according to the present invention comprises an interlayer distance detecting means for obtaining an interval between adjacent information surfaces based on a signal from the stray light measuring means, and a focus according to a result of the interlayer distance detecting means. It is characterized in that it comprises a parameter setting means for setting a parameter of the jump means.

The signal output from the focus jump means of the optical disk device according to the present invention is composed of an acceleration pulse and a deceleration pulse according to the parameters set toward the desired information surface, and the parameter setting means is the interlayer distance detecting means. The peak value of the acceleration pulse or the deceleration pulse of the focus jump means is changed according to the result.

The parameter setting means of the optical disk apparatus according to the present invention is set so as to reduce the peak value of the acceleration pulse or deceleration pulse of the focus jump means when the result of the interlayer distance detection means is shorter than a predetermined distance. Is characterized by.

The parameter setting means of the optical disk device according to the present invention is set to increase the peak value of the acceleration pulse or deceleration pulse of the focus jump means when the result of the interlayer distance detection means is longer than a predetermined distance. Is characterized by.

The parameter setting means of the optical disk device according to the present invention is characterized in that the output time width of the acceleration pulse or deceleration pulse of the focus jump means is changed according to the result of the interlayer distance detection means.

The parameter setting means of the optical disk device according to the present invention is characterized in that the output time width of the acceleration pulse or deceleration pulse of the focus jump means is shortened when the result of the interlayer distance detection means is shorter than a predetermined distance. And

The parameter setting means of the optical disc apparatus according to the present invention is characterized in that when the result of the interlayer distance detecting means is longer than a predetermined distance, the acceleration pulse or deceleration pulse output time width of the focus jump means is lengthened. To do.

The optical disk device according to the present invention comprises moving means for moving the convergent point of a light beam converged on an information carrier having a plurality of stacked information surfaces in a direction substantially perpendicular to the information surface, and information. Convergence state detection means for generating a signal according to the convergence state of the light beam on the carrier, and driving the moving means in response to a focus error signal which is an output signal from the convergence state detection means Focus control means for controlling the focusing position of the beam to be substantially constant, and outputting a predetermined signal to the focusing control means so that the convergence point of the light beam is changed from any information surface of the information carrier to another information surface. Total reflection for detecting the light amount of the light beam outside the detection range of the focus state detecting means and the focus state detecting means, and generating a signal according to the total light amount of the light beam reflected from the information carrier. Includes a quantity detecting means, the focus jump means, based on a signal from the total reflected light amount detecting means, characterized in that it comprises a jump signal generating means for generating a jump signal for driving the moving means.

The jump signal generating means of the optical disk device according to the present invention generates an acceleration pulse and a deceleration pulse that are output toward the desired information surface, and based on the result of the total reflection light amount detecting means, The output timings of the acceleration pulse and the deceleration pulse are controlled.

The jump pulse generating means of the optical disk device according to the present invention is such that when the result of the total reflection light amount detecting means during the output of the acceleration pulse becomes smaller than a predetermined result,
It is characterized in that the acceleration pulse output of the focus jump means is terminated.

The jump pulse generating means of the optical disk device according to the present invention outputs the deceleration pulse output of the focus jump means when the result of the total reflection light amount detecting means waiting for the deceleration pulse output becomes larger than a predetermined result. It is characterized by starting.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below.

(Embodiment 1) FIG. 1 is a block diagram of an optical disk device according to the first embodiment. In FIG. 1, the same components as those of FIG. 21, which is a conventional technique, are denoted by the same reference numerals and description thereof will be omitted. The stray light measuring means is the stray light measuring device 21. The interlayer distance detecting means is an interlayer distance detector 2
It is 2. The parameter setting means is the parameter setter 23
Is.

The split photodetector 24 sends a light amount signal to the FE generator 9 and the stray light measuring device 21 using the light beam reflected by the polarization beam splitter 4. With the focus point of the light beam being focus-controlled on a certain information surface on the optical disc having a plurality of information surfaces, the stray light measuring instrument 21 is divided into the divided photodetectors 24.
From the information surface that is not the focus control target (hereinafter referred to as NS signal) to the interlayer distance detector 22. The interlayer distance detector 22 detects the distance between the current information surface of the focus control target and the information surface of the focus jump target from the value of the NS signal, and outputs a signal according to the distance (hereinafter referred to as an information surface distance signal). It is sent to the parameter setter 23. The parameter setter 23 sends a signal related to the acceleration pulse crest value and deceleration pulse crest value of the jump pulse according to the information surface distance signal to the jump pulse generator 1.
Send to 2.

The split photodetector 24 will be described with reference to FIGS. FIG. 2 shows the arrangement of the photodetectors of the split photodetector 24. A sub-photodetector 31 is installed outside the four-divided main photodetector 30 so that a sufficient amount of received light can be obtained even when the convergence point on the information surface of the light beam is blurred. The elliptical shape of the light beam on the split photodetector 24 changes depending on the position of the convergence point due to astigmatism. FIG. 3 shows the light receiving states of the main photo detector 30 and the sub photo detector 31 when the convergence point of the light beam is in front of the information surface of the control target. FIG. 4 shows the light receiving state of the photodetector when the convergence point of the light beam is converged on the information surface of the control target. FIG. 5 shows the light receiving state of the photodetector when the converging point of the light beam is behind the information surface of the control target. As shown in FIGS. 3 and 5,
When the converging point of the light beam is separated from the information surface, the converging point of the light beam on the photodetector is also blurred, so that the amount of light incident on the sub-photodetector 31 increases.

The signal generated by the split photodetector 24 will be described with reference to FIG. FIG. 6 shows a photodetector A 32, a photodetector B 33, a photodetector C 34, a photodetector D 35, and a sub-photodetector 31 which constitute the main photodetector 30. The split photodetector 24 sends the received light amounts of the photodetector A 32, the photodetector B 33, the photodetector C 34, and the photodetector D 35 to the FE generator 9.
The split photodetector 24 sends the amount of light received by the sub-photodetector 31 to the stray light measuring instrument 21.

FIG. 7 shows each signal when the condenser lens 5 is moved toward the information surface of the optical disc 1. The waveform a is the position of the convergence point of the light beam, and the waveform b is the F from the FE generator 9.
The E signal and the waveform c indicate the NS signal from the stray light measuring instrument 21. In FIG. 7, the convergence point of the light beam is converged on the information surface of the control target at time t0. As the convergence point of the light beam approaches the information surface, the light beam converges into the main photodetector 30 and the subphotodetector 31.
The amount of received light is reduced and the output of the NS signal is reduced.

A method of detecting the interlayer distance in the case where the optical disc to be controlled has a multi-layer information surface will be described with reference to FIGS. 8 and 9 by taking a double-layer disc having two information surfaces as an example. FIG. 8 shows each signal when the condenser lens 5 is brought closer to the two-layer disc having a short information surface distance. The waveform a shows the position of the convergence point of the light beam with respect to the information surface, the waveform b shows the FE signal from the FE generator 9, and the waveform c shows the NS signal from the stray light measuring instrument 21, respectively.
In the case of a dual-layer disc, the light beam converges on the first information surface when viewed from the condenser lens 5 at time t10,
At 11, the light beam converges on the second information surface when viewed from the condenser lens 5. d10 indicates the distance between the two information surfaces. m10 indicates the detection level of the NS signal in each state at time t10, and m20 indicates the detection level of the NS signal in each state at time t20.

On the contrary, FIG. 9 shows each signal when the condensing lens 5 is brought closer to a two-layer disc having a distance between information surfaces. Similar to FIG. 8, the waveform a shows the position of the convergence point of the light beam with respect to the information surface, the waveform b shows the FE signal from the FE generator 9, and the waveform c shows the NS signal from the stray light measuring instrument 21, respectively. At time t20, the light beam converges on the first information surface as seen from the condenser lens 5, and at time t21, the light beam converges on the second information surface as seen from the condenser lens 5. d20 indicates the distance between the two information surfaces. m20 indicates the detection level of the NS signal in each state at the time t20 and m21 at the time t21.

In the case of a dual-layer disc, the information beam that is not the current focus control target is irradiated with the light beam, and as a result, the reflected light (hereinafter referred to as stray light) from the information surface is shown in FIGS. 3 and 5. Thus, the light enters the sub-photodetector 31. Therefore, even when the focus control is performed on either one of the information surfaces, the NS signal from the split photodetector 24 is output as a value larger than the zero level. The closer the distance between the information planes, the stronger the influence of stray light, and the higher the level of the NS signal output from the split photodetector 24. On the contrary, if the distance between the information planes is long,
Since the effect of stray light incident on the sub-photodetector 31 is weakened, the level of the NS signal output from the split photodetector 24 becomes low. 8 and 9, assuming that the distance relationship between the information surfaces is d10 <d20, the NS signal levels at the focus control points are m10> m20 and m11.
> M21.

A flow chart of the operation of the inter-layer distance detector 22 using the NS signal is shown in FIG. The interlayer distance detector 22 receives the NS signal from the stray light measuring instrument 21 in the focus control state (S100), and compares it with the value of the NS signal at the interlayer distance based on the value of the received NS signal (S101). If the NS signal in the converged state is higher than the level of the reference NS signal, it is determined that the distance to the information surface of another layer is close, and the information surface distance signal of the polarity indicating the closeness is output to the parameter setting unit 23. Yes (S10
2). On the contrary, if the NS signal is smaller than the reference NS signal level, the inter-layer distance detector 22 determines that the distance to the information surface of another layer is far, and sets a parameter of the information inter-distance distance signal having a polarity indicating that the distance is far. Output to the container 23 (S10
3).

Operation of the parameter setter 23 FIG.
1 is shown using a flowchart. Parameter setter 2
3 receives the information surface distance signal from the interlayer distance detector 22 (S200). The value of the inter-information-plane distance signal is compared with the reference value (S201), and when it is shown that the distance is longer than the reference inter-layer distance, the parameter setter 23 determines that the information plane is increased in order to increase the impulse of the jump pulse. The values of the acceleration pulse crest value and the deceleration pulse crest value of the focus jump are increased according to the value of the inter-distance signal (S202). On the contrary, when the value of the information surface distance signal is closer than the reference interlayer distance, the parameter setter 23 responds to the value of the information surface distance signal in order to reduce the impulse of the jump pulse. Then, the values of the acceleration pulse crest value and the deceleration pulse crest value of the focus jump are decreased (S203).

FIG. 23 shows a focus jump waveform when the crest value of the acceleration pulse and the crest value of the deceleration pulse are changed according to the interlayer distance between the information surfaces. Waveform a, waveform b, waveform c, and waveform d show respective signals when the distance between the information planes is short, the waveform a shows the position of the convergence point of the light beam with respect to the information plane, and the waveform b shows the signal from the FE generator 9. The FE signal, the waveform c represents the drive signal from the Fc driver 11, and the waveform d represents the NS signal from the stray light measuring instrument 21. A waveform e, a waveform f, a waveform g, and a waveform h represent respective signals of a focus jump when the distance between the information planes is long, the waveform e indicates the position of the convergence point of the light beam with respect to the information plane, and the waveform f indicates the FE generator. FE from 9
, The waveform g represents the drive signal from the Fc driver 11,
The waveform h shows the NS signal from the stray light measuring instrument 21.

In this way, as shown in FIG.
By increasing or decreasing the jump crest value corresponding to the interlayer distance between the information surfaces obtained using the signal, the focus jump time becomes constant regardless of the interlayer distance between the information surfaces, and an optical disc device with a stable focus jump is provided. Can be provided.

In the first embodiment, the photodetector in which the sub-photodetector is arranged so as to surround the main photodetector has been described, but it is possible to receive light even when the convergence point of the light beam is blurred. For example, if the sub-photodetectors are separately arranged outside the main photodetector and the sum signal thereof is used, the same effect can be obtained.

Although the first embodiment has been described by using the two-layer disc, it is clear that the present invention can be applied to the case of using the multi-layer disc having three or more information surfaces. There is no limitation whatsoever due to the description of those having.

In the first embodiment, the jump pulse crest value is changed to change the impulse. However, as shown in the flowchart of FIG. 12, the parameter setter 23 changes the jump pulse output time to set the force. Even when the product is changed, the same effect can be obtained as shown in FIG. FIG. 24 shows a focus jump waveform when the output time of the acceleration pulse and the output time of the deceleration pulse are changed according to the interlayer distance between the information surfaces. The waveform a, the waveform b, the waveform c, and the waveform d represent the respective signals when the distance between the information planes is short.
Is the position of the convergence point of the light beam with respect to the information surface, waveform b is the FE signal from the FE generator 9, waveform c is the drive signal from the Fc driver 11, and waveform d is the NS signal from the stray light measuring instrument 21. Waveforms e, f, g, and h indicate focus jump signals when the distance between the information planes is long, the waveform e indicates the position of the convergence point of the light beam with respect to the information plane, and the waveform f indicates FE. The FE signal from the generator 9 is converted into the waveform g
Indicates the drive signal from the Fc driver 11, and the waveform h indicates the NS signal from the stray light measuring instrument 21.

(Second Embodiment) FIG. 13 shows a block diagram of an optical disk device according to the second embodiment. In FIG. 13, FIG. 1 showing the first embodiment and FIG. 2 showing the conventional technique.
The same components as those of component 1 are designated by the same reference numerals and the description thereof will be omitted. The total reflection light measuring means is a total reflection light amount measuring device 40. The focus jump means is the jump command device 13 and the jump pulse generator 42.

The split photodetector 24 sends a light amount signal to the FE generator 9 and the total reflection light amount measuring device 40 using the light beam reflected by the polarization beam splitter 4. Total reflection light measuring instrument 4
0 uses the signal sum from the split photodetector 24 to send a signal (hereinafter referred to as a BS signal) corresponding to the level of the reflected light from the information surface to the jump pulse generator 42. While receiving the jump operation signal from the jump command device 13, the jump pulse generator 42 sends the jump pulse signal to the Fc driver 11 according to the FE signal from the FE generator 9 and the BS signal from the total reflection light amount measuring device 40. Send to.

The signal generated from the split photodetector 24 will be described with reference to FIG. FIG. 14 shows a photodetector A 32, a photodetector B 33, a photodetector C 34, a photodetector D 35, and a sub-photodetector 31 which constitute the main photodetector 30, respectively. The split photodetector 24 is a photodetector A3.
2, photo detector B33, photo detector C3
4. The FE generator 9 calculates the amount of light received by the photodetector D35.
And send it to the total reflection light quantity measuring device 40. The split photodetector 24 measures the amount of light received by the sub-photodetector 31 by the total reflection light amount measuring device 4
Send to 0.

The total reflected light amount will be described with reference to FIG. The total amount of light received by the main photodetector 30 divided into four and the amount of light received by the sub-photodetector 31, which are used to generate the FE signal, are added together and multiplied by a predetermined gain to be used as the amount of total reflected light.

FIG. 15 shows each signal when the condenser lens 5 is moved toward the information surface of the optical disc. The waveform a is the position of the convergence point of the light beam, and the waveform b is the F from the FE generator 9.
Waveform c shows the E signal, and the BS signal from the total reflection light amount measuring device 40. In FIG. 7, the point of time t30 is the state where the convergence point of the light beam is converged on the information surface of the control target.
As the convergence point of the light beam approaches the information surface, the BS signal level also increases. In FIG. 15, at time t30, the convergence point of the light beam is converged on the information surface of the control target, and the total reflected light amount is maximum. On the contrary, it decreases as the convergence point of the light beam moves away from the information surface.

The sub-photodetector 3 is added to the BS signal.
The detection range of the BS signal is wider than the detection range of the FE signal because the received light component of 1 is included and the reflected light can be detected even when the light beam is not sufficiently converged. As an example in the case where the optical disc to be controlled has a multi-layered information surface, each signal in the case of a dual-layer disc having two information surfaces is shown in FIG. Similar to FIG. 15, the waveform a shows the position of the convergence point of the light beam, the waveform b shows the FE signal from the FE generator 9, and the waveform c shows the BS signal from the total reflection light quantity measuring device 40.

The operation of the jump pulse generator 42 will be described with reference to the flowchart of FIG. The jump pulse generator 42 receives the BS signal from the total reflection light amount measuring device 40 (S300). The jump pulse generator 42 is BS
The value of the signal is compared with a predetermined pulse output condition (S30
1). If the value of the BS signal exceeds the predetermined level, the jump pulse generator 42 outputs the jump pulse signal to the selector 14 (S302). On the contrary, when the value of the BS signal does not exceed the predetermined level, the jump pulse generator 42 selects the jump pulse signal selector 1
A zero level signal to 4 is output (S303).

Regarding the focus jump method using the BS signal, two information planes (hereinafter referred to as L0 and L1 respectively)
A case of moving from L0 to L1 with a dual-layer disc having a (referred to as) will be described with reference to FIGS. 18 and 19. FIG. 18 shows a signal at the time of outputting an acceleration pulse when the focus jump is made from L0 to L1. Waveform a is FE
The FE signal from the generator 9, the waveform b, the BS signal from the total reflection light amount measuring device 40, the waveform c, the driving signal from the Fc driver 11, and the waveform d, the jump operation signal from the jump command device 13, respectively. ing. The acceleration pulse output continuation level is set to h40, and acceleration is started at time t40. Since the convergence point on the information surface of the light beam becomes blurred as it accelerates, the FE signal cannot be detected at time t41. When the output of the acceleration pulse is determined based only on the FE signal, the output of the acceleration pulse can be continued only until the time t41. However, due to the effect of the sub-photodetector 31 arranged so that a sufficient signal can be obtained in a wider range than that of the FE generator 9, it is possible to judge the output based on the BS signal.

The jump pulse generator 42 continues to output the acceleration pulse signal until time t42 when the BS signal becomes equal to or lower than the set level of h40. Since the jump pulse generator 42 continues to output the acceleration pulse until the time t42, it is possible to set an acceleration time longer than that of the conventional method, and sufficient acceleration can be achieved even when the FE signal detection range is narrow. It will be possible.

FIG. 19 shows signals at the time of deceleration pulse output after the acceleration pulse output at the time of the focus jump from L0 to L1. The waveform a is the FE from the FE generator 9.
The signal, the waveform b, the BS signal from the total reflection light amount measuring device 40, the waveform c, the drive signal from the Fc driver 11, and the waveform d, the jump operation signal from the jump command device 13, respectively. Deceleration pulse output level is set to h41,
Deceleration is started at time t43. Since it approaches L1, the FE signal can be detected from time t44. When the output of the deceleration pulse is determined based on the conventional FE signal, the output of the deceleration pulse cannot be started until the time t44. If the output determination is performed using the BS signal level in the same manner as during acceleration, the deceleration start pulse can be output from an earlier point.

The jump pulse generator 42 starts outputting the deceleration pulse at time t43 when the BS signal becomes equal to or higher than the set level of h41. Jump pulse generator 42 By starting the output of the deceleration pulse from this time t43, more deceleration time can be set than in the conventional method, and optimal deceleration is possible even when the detection range of the FE signal is narrow. Become.

FIG. 20 shows a focus jump waveform using the BS signal. The waveform a is the FE signal from the FE generator 9, the waveform b is the BS signal from the total reflection light amount measuring device 40, the waveform c is the drive signal from the Fc driver 11, and the waveform d is the jump from the jump command device 13. Each operation signal is shown. By extending the acceleration pulse output time and the deceleration pulse output time as compared with the conventional method using the FE according to the present embodiment, the deceleration pulse start waiting time (time t42) occupied during the jump operation (from time t40 to time t45). It is possible to provide a stable optical disk device that does not run backward during a focus jump.

In the second embodiment, the photodetector in which the sub photodetector is arranged so as to surround the main photodetector is used, but the FE generator 9 is used.
Even if the sub detectors are arranged outside the main photo detector to have a wider detection area than the main photo detector so that a sufficient amount of light can be detected even if the convergence point of the light beam is blurred, the sum signal is used. Naturally, the same effect can be obtained.

Naturally, when moving from L1 to LO, the same effect can be obtained with the same configuration.

Although the second embodiment has been described using the two-layer disc, it is obvious that the present invention can be applied to the case of using a multi-layer disc having three or more information surfaces. There is no limitation whatsoever due to the description of those having.

Further, in the second embodiment, both the acceleration pulse and the deceleration pulse are explained as the constant peak value, but the pulse peak value may be changed during the output.

[0057]

According to the present invention, the focus jump means for moving the convergence point of the light beam from any information surface of the information carrier to another information surface, and the focus jump means adjacent to the information surface on which the light beam is converged. Stray light measuring means for measuring the amount of reflected light from the information surface, and jump pulse setting means for setting the pulse output of the focus jump means according to the result of the stray light measuring means are provided, so that it is stable without being affected by stray light. Focus jump can be realized.

The jump pulse setting means of the optical disk device according to the present invention is an interlayer distance detecting means for obtaining an interval between adjacent information surfaces based on a signal of the stray light measuring means, and a focus jump according to the result of the interlayer distance detecting means. Since it has a parameter setting means for setting the parameters of the means,
A stable focus jump can be performed according to the distance between layers.

The signal output from the focus jump means of the optical disk device according to the present invention is composed of an acceleration pulse and a deceleration pulse according to the parameters set toward the desired information surface, and the parameter setting means is the interlayer distance detecting means. Since the peak value of the acceleration pulse or deceleration pulse of the focus jump means is changed according to the result, it is possible to realize a stable focus jump that is not affected by the interlayer distance.

Therefore, it is possible to provide a highly reliable and stable device.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a first embodiment.

FIG. 2 is a diagram showing the arrangement of photodetectors in a split photodetector 24.

FIG. 3 is an explanatory diagram of a light receiving state of each photodetector of the split photodetector 24 when the light is converged in front of the information surface.

FIG. 4 is an explanatory diagram of a photodetector light receiving state of the split photodetector 24 when it is focused on an information surface.

FIG. 5 is a split photodetector 2 when it is focused on the back of the information surface.
Explanatory drawing about each photodetector light receiving state of 4

FIG. 6 is an explanatory diagram of a signal output destination of the photodetector 8 in the first embodiment.

FIG. 7 is a signal waveform diagram when the condenser lens 5 is brought closer to the information surface in the first embodiment.

FIG. 8 is a signal waveform diagram when the condensing lens 5 is brought close to the information surface in the dual-layer disc in which the distance between the information surfaces is short in the first embodiment.

FIG. 9 is a signal waveform diagram when the condensing lens 5 is brought close to the information surface in the dual-layer disc in which the distance between the information surfaces is long in the first embodiment.

FIG. 10 is a flowchart showing the processing of the interlayer distance detector 14 in the first embodiment.

FIG. 11 is a flowchart showing processing of the parameter setting unit 23 in the first embodiment.

FIG. 12 is a flowchart showing processing when the parameter setter 23 changes the jump pulse output time in the first embodiment.

FIG. 13 is a block diagram showing the configuration of the second embodiment.

FIG. 14 is a connection diagram from the split photodetector 24 to the FE generator 9 and the total reflection light amount measuring device 40 in the second embodiment.

FIG. 15 is a signal waveform diagram when the condenser lens is brought closer to the information surface of the single-layer disc in the second embodiment.

FIG. 16 is a signal waveform diagram when the condenser lens is brought closer to the information surface of the dual-layer disc in the second embodiment.

FIG. 17 is a flowchart showing the process of the jump pulse generator 12 using the BS signal in the second embodiment.

FIG. 18 is a signal waveform diagram at the time of focus jump acceleration using the BS signal in the second embodiment.

FIG. 19 is a signal waveform diagram at the time of focus jump deceleration using the BS signal in the second embodiment.

FIG. 20 is a signal waveform diagram of the entire focus jump operation using the BS signal in the second embodiment.

FIG. 21 is a block diagram showing the configuration of a conventional device.

FIG. 22 is a diagram showing a focus jump waveform in a conventional device.

FIG. 23 is a signal waveform diagram when the jump crest value is changed according to the interlayer distance in the first embodiment.

FIG. 24 is a signal waveform diagram when the jump output time width is changed according to the interlayer distance in the first embodiment.

[Explanation of symbols]

1 optical disc 2 optical head 3 Semiconductor laser 4 Polarizing beam splitter 5 Condensing lens 6 Focus actuator 8 Photodetector 9 FE generator 10 Fc filter 11 Fc driver 12 Jump pulse generator 13 Jump command device 14 Selector 21 Stray light measuring instrument 22 Interlayer distance detector 23 Parameter setter 24-split photodetector 30 Main Photo Detector 31 Sub Photo Detector 32 Photo Detector A 33 Photo Detector B 34 Photo Detector C 35 Photo Detector D 40 Total reflection light quantity measuring instrument 42 Jump pulse generator

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Katsuya Watanabe             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. F-term (reference) 5D117 AA02 BB01 DD00 FF00 FF06

Claims (12)

[Claims] 1. A moving means for moving a convergence point of a light beam focused on an information carrier having a plurality of information planes stacked in a direction substantially perpendicular to the information surface, and a moving means for moving the light beam on the information carrier. A convergent state detecting means for generating a signal according to the convergent state, and the moving means in response to a focus error signal which is an output signal from the convergent state detecting means, so that the convergent state of the light beam on the information carrier is substantially A focus control means for controlling each of them to be constant, a predetermined signal is output to the focus control means, a signal is output to the moving means, and the convergence point of the light beam is changed from an arbitrary information surface of the information carrier to another. Focus jump means for moving to the information surface, stray light measuring means for measuring the amount of reflected light from the information surface adjacent to the information surface on which the light beam is converged, and the focus according to the result of the stray light measuring means. An optical disk device comprising jump signal output setting means for setting the signal output of the jump means. 2. The jump signal output setting means sets an interlayer distance detecting means for obtaining an interval between adjacent information surfaces based on a signal from the stray light measuring means, and a parameter of the focus jump means according to a result of the interlayer distance detecting means. The optical disk device according to claim 1, further comprising parameter setting means for setting. 3. A signal output from the focus jump means is composed of an acceleration pulse and a deceleration pulse according to a parameter set in the direction of a desired information plane, and the parameter setting means is responsive to the result of the interlayer distance detecting means. 3. The optical disk device according to claim 2, wherein the peak value of the acceleration pulse or deceleration pulse of the focus jump means is changed. 4. The parameter setting means is set to reduce the peak value of the acceleration pulse or deceleration pulse of the focus jump means when the result of the interlayer distance detection means is shorter than a predetermined distance. Item 3. The optical disk device according to item 3. 5. The parameter setting means is set to increase the peak value of the acceleration pulse or deceleration pulse of the focus jump means when the result of the interlayer distance detection means is longer than a predetermined distance. Item 3. The optical disk device according to item 3. 6. The optical disk device according to claim 2, wherein the parameter setting means changes the output time width of the acceleration pulse or deceleration pulse of the focus jump means according to the result of the interlayer distance detection means. 7. The parameter setting means shortens the output time width of the acceleration pulse or the deceleration pulse of the focus jump means when the result of the interlayer distance detecting means is shorter than a predetermined distance. The optical disk device described. 8. The parameter setting means lengthens the acceleration pulse or deceleration pulse output time width of the focus jump means when the result of the interlayer distance detecting means is longer than a predetermined distance. Optical disk device. 9. A moving means for moving a convergence point of a light beam converged on an information carrier having a plurality of stacked information surfaces in a direction substantially perpendicular to the information surface, and a moving means of the light beam on the information carrier. A convergent state detecting means for generating a signal according to the convergent state, and the moving means in response to a focus error signal which is an output signal from the convergent state detecting means so that the convergent position of the light beam on the information carrier is substantially Focus control means for controlling each of them to be constant, and focus jump means for outputting a predetermined signal to the focus control means to move the convergence point of the light beam from any information surface of the information carrier to another information surface. And a total reflection light amount detection means for detecting a light amount of the light beam outside the detection range of the convergence state detection means and generating a signal according to the total light amount of the light beam reflected from the information carrier. The dregs jumping means includes a jump signal generating means for generating a jump signal for driving the moving means based on a signal from the total reflection light amount detecting means. 10. The jump signal generating means generates an acceleration pulse and a deceleration pulse which are output toward a desired information surface, and based on the result of the total reflection light amount detecting means, the acceleration pulse and the deceleration pulse. 10. The optical disk device according to claim 9, wherein the output timing of the pulse is controlled. 11. The jump pulse generating means ends the acceleration pulse output of the focus jump means when the result of the total reflection light amount detecting means during the acceleration pulse output becomes smaller than a predetermined result. Claim 10
The optical disk device described. 12. The jump pulse generation means starts the deceleration pulse output of the focus jump means when the result of the total reflection light amount detection means waiting for the deceleration pulse output becomes larger than a predetermined result. The optical disk device according to claim 10.