JP2864937B2 - Information recording disk playback device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording disk reproducing apparatus for reproducing recorded information using optical means.

[0002]

2. Description of the Related Art In recent years, information recording disk reproducing apparatuses have been widely applied in the consumer field, and reproducing apparatuses such as compact disks and laser visions have been actively developed.

[0003] A conventional information recording disk reproducing apparatus will be described below. FIG. 3 shows a block diagram of this conventional information recording disk reproducing apparatus.

[0004] In FIG. 3, 1 is a light detector for focus error detection, a differential amplifier 2 to generate a focus error, respectively system for 3p and 3n is the focal position adjustment
Two focus balance adjustment voltage control amplifiers having different polarities , 6 is a gain control terminal of the voltage control amplifiers 3p and 3n.
This is a voltage source that stores a focus balance adjustment value to be supplied to the element.

[0005] The two signals of the photodetector 1 are input to voltage control amplifiers 3p and 3n, respectively, amplified by a focus balance given by a voltage source 6, and then converted into a focus error by a differential amplifier 2.

Here, the focus balance provided by the voltage source 6 is adjusted in advance so that the reproduction capability is maximized. When the focus error, which is the output of the differential amplifier 2, becomes zero, the information is adjusted. The focus is adjusted so that the information surface of the recording disk coincides with the focal point of the light beam.

[0007]

However, in the above-described conventional configuration, when the focus balance is adjusted so that the reproduction capability is maximized, the amplification factor of the voltage amplifiers 3p and 3n greatly differs depending on the state of the optical system. Occurs, and the maximum output voltage of the voltage control amplifier 3p and the maximum output voltage of the voltage control amplifier 3n greatly differ, and the dynamic range of the focus error signal becomes unbalanced as shown by the curve 22 in FIG. There are cases.

[0008] When the focus pull-in is performed in such a focus balance adjustment state, there is a problem that the focus pull-in may fail due to a shortage of a dynamic range.

An object of the present invention is to solve the above-mentioned conventional problems, and an object of the present invention is to provide an information recording disk reproducing apparatus capable of maximizing not only reproduction capability but also focus pull-in capability.

[0010]

In order to achieve this object, an information recording disk reproducing apparatus according to the present invention separately outputs two outputs of a multi-divided photodetector which outputs according to incident light. What is claimed is: 1. An information recording disk reproducing apparatus for detecting a focus error of an incident light by amplifying and adding, comprising two voltage controlled amplifiers having different control polarities, each of which receives two outputs of a photodetector and adjusts a balance. When,
Focus balance to maximize focus pull-in performance
Voltage to provide a regulated state, and a focus to maximize the playback capacity
And two variable voltage sources and voltage applied to scan balancing state, the voltage selector switch supplies the selected one of the voltage of the variable voltage source to the gain control terminal of the voltage control amplifier, electrostatic
It has a configuration in which a control unit for switching the pressure change-over switch.

[0011]

According to the present invention, it is possible to use the focus balance adjustment value that maximizes the reproduction capability at the time of reproduction and the focus balance adjustment value that maximizes the pull-in capability at the time of focus pull-in. In addition, it is possible to provide an information recording disk reproducing device that can maximize the focus pull-in capability.

[0012]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an information recording disk reproducing apparatus according to an embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes a photodetector for detecting a focus error, 2 denotes a differential amplifier for generating a focus error, and 3p and 3n denote two focus balances having different control polarities for adjusting a focus position. An adjustment voltage control amplifier, 5 is a voltage source storing two kinds of focus balances, and 4 is a voltage switch (hereinafter simply referred to as a switch).
(Referred to as a changeover switch) .

FIG. 2 is a characteristic diagram showing how the focus error signal changes depending on the lens position with respect to the disk. The curve 21 shows the focus error when the focus balance adjustment value having the maximum focus pull-in performance is used. The curve 22 shows a focus error when the focus balance adjustment value having the maximum reproduction performance is used.

The operation of the information recording disk reproducing apparatus of the present embodiment configured as described above will be described below.

First, a voltage that gives a focus balance adjustment value that maximizes the focus pull-in performance is set to the voltage source 6a, and a voltage that gives a focus balance adjustment value that maximizes the reproduction performance is set to the voltage source 6b. And

When the disc is set in the information recording disc reproducing apparatus and the focusing operation is performed, the control unit 4 switches the changeover switch 5 so that the voltage of the voltage source 6a is applied to the voltage control amplifiers 3p and 3n. . At this time, FIG.
As shown by the curve 21 , the dynamic range of the focus error becomes the maximum, and the focus pull-in can be performed stably.

When the focus pull-in is completed and the reproduction is started, the control unit 4 sets the voltage of the voltage source 6b to the voltage control amplifier 3p.
And 3n.
At this time, as shown by a curve 22 in FIG. 2 , when the focus error signal voltage is zero, the focus of the light beam coincides with the signal surface of the information recording disk, and the best reproduction signal quality can be obtained.

As described above, according to the present embodiment, two voltages of different control polarities, each of which receives two outputs of a multi-divided photodetector and adjusts the balance, which output according to the incident light. Maximum control amplifier and focus pull-in performance
And the voltage that gives the focus balance adjustment state
Give the focus balance adjustment state that maximizes the live performance
Providing two variable voltage sources of the voltage that the voltage selector switch supplies the selected one of the voltage of the variable voltage source to the gain control terminal of the voltage controlled amplifier, and a control unit for switching the voltage selector switch This allows the focus balance adjustment value that maximizes the playback capability to be used during playback, and the focus balance adjustment value that maximizes the pull-in capability to be used when pulling in the focus. It is possible to provide an information recording disk reproducing apparatus capable of performing the above.

[0021]

As described above, according to the present invention, the focus error of the incident light is obtained by individually amplifying the two outputs of the multi-divided photodetector, which is output according to the incident light, and then adding them. a detection information recording disk reproducing apparatus and to adjust the inputs, respectively balanced two outputs of the photodetector, two voltage controlled amplifier and having different control polarities, off
Focus balance adjustment for maximum focusing performance
Voltage to give state and focus to maximize playback capability
And two variable voltage sources and voltage to provide a balance state, and a voltage selector switch supplies by selecting one of the voltage of the variable voltage source to the gain control terminal of the voltage control amplifier, electrostatic
By providing a control unit for switching the pressure change-over switch, is using the focus balance adjustment value reproduction ability is maximum at the time of reproduction, can be used the focus balance adjustment value drawing power is maximized at the time of focus pull,
It is possible to provide an information recording disk reproducing device capable of maximizing not only reproduction capability but also focus pull-in capability.

[Brief description of the drawings]

FIG. 1 is a block diagram of an information recording disk reproducing apparatus according to an embodiment of the present invention.

FIG. 2 is a graph showing characteristics of a focus error signal in one embodiment of the present invention.

FIG. 3 is a block diagram of a conventional information recording disk reproducing apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photodetector 2 Differential amplifier 3p Voltage control amplifier 3n Voltage control amplifier 4 Control part 5 Changeover switch 6a Voltage source 6b Voltage source

Claims (1)

(57) [Claims] 1. An information recording disk for detecting a focus error of incident light by individually amplifying and adding two outputs of a multi-divided photodetector, which outputs according to incident light, respectively. a reproducing apparatus, to adjust the inputs, respectively balanced two outputs of the photodetector, two voltage controlled amplifier and having different control polarities, focus pull performance
That gives the focus balance adjustment state that maximizes
And focus balance adjustment state that maximizes playback capability
And two variable voltage sources and voltage applied to the control performed with the voltage change-over switch for supplying by selecting one of the voltage of the variable voltage source to the gain control terminal of the voltage controlled amplifier, the switching of the voltage selector switch Information recording disk reproducing device comprising: