JPS62202620U

JPS62202620U -

Info

Publication number: JPS62202620U
Application number: JP8856586U
Authority: JP
Priority date: 1986-06-12
Filing date: 1986-06-12
Publication date: 1987-12-24
Also published as: JPH0433543Y2

Description

[Brief explanation of the drawing]

第１図および第２図は、この考案に係るフオー
カスサーボ装置の実施例を示すもので、第１図は
全体構成を示すブロツク図、第２図は第１図の要
部の動作説明用の特性図である。第３図乃至第５
図Ａ，Ｂは、従来例を示すもので、第３図はブロ
ツク図、第４図および第５図Ａ，Ｂはそれぞれ特
性図である。１：光ピツクアツプ、２：ＦＥ検出部、３：コ
ンパレータ、４：コントロール回路、５：補償回
路、６：フオーカスサーチ回路、７：出力アンプ
、８：デイスク、ＳＷ１，ＳＷ２，ＳＷ３：スイ
ネチ、ＯＦＳ……オフセツト電圧。 Figures 1 and 2 show an embodiment of the focus servo device according to this invention. Figure 1 is a block diagram showing the overall configuration, and Figure 2 is for explaining the operation of the main parts of Figure 1. FIG. Figures 3 to 5
Figures A and B show a conventional example, Figure 3 is a block diagram, and Figures 4 and 5 A and B are characteristic diagrams, respectively. 1: Optical pickup, 2: FE detection section, 3: Comparator, 4: Control circuit, 5: Compensation circuit, 6: Focus search circuit, 7: Output amplifier, 8: Disk, SW1, SW2, SW3: Switch, OFS ...Offset voltage.

Claims

[Claims for Utility Model Registration] (1) In a focus servo device configured to close a focus servo loop in response to the output of a detection means for detecting zero crossing of a focus error signal, An offset means for applying a negative or positive potential offset in advance is provided, and when the detection means detects a zero cross in the process of the actuator approaching the effective range of the focus error signal, the offset is set to approximately zero potential, The focus servo device is further configured to stop applying the offset and close the focus servo loop when the detection means detects a zero cross within the effective range of the focus error signal. (2) When the detection means detects a zero cross in the process of the actuator approaching the effective range of the focus error signal, the approximately zero potential offset applied to the focus error signal is changed to a slightly negative or positive potential. The focus servo device according to claim 1, further comprising an offset means configured to set the focus servo device. (3) The offset means is connected to a negative or positive power supply;
A first resistor, the negative or positive potential offset of which is configured to be applied to the input of a detection means for detecting a zero crossing of a focus error signal. The focus servo device according to item 1. (4) The offset means includes a first offset consisting of a negative or positive power supply and a first resistor, and a second offset provided by the output of the detection means for detecting the zero crossing of the focus error signal and a second resistor. Utility model registration claim 1 characterized in that the utility model is configured to give an offset equal to the sum of the offset of
The focus servo device described in . (5) The offset means includes a first offset consisting of a negative or positive power source and a first resistor, an output of the detection means for detecting the zero crossing of the focus error signal, and a second offset that provides a time constant for the output. 2. The focus servo device according to claim 1, wherein the focus servo device is configured to provide an offset equal to the sum of a second offset consisting of a resistor and a capacitor. (6) Utility model registration claim 1, characterized in that a switch means is provided for stopping the offset application of the offset means based on the detection output when the detection means detects a zero cross within the effective range of the focus error signal. The focus servo device described in .