JPH0352819U

JPH0352819U -

Info

Publication number: JPH0352819U
Application number: JP11182589U
Authority: JP
Priority date: 1989-09-25
Filing date: 1989-09-25
Publication date: 1991-05-22

Description

[Brief explanation of the drawing]

第１図、第７図はそれぞれ本考案になる光ピツ
クアツプ装置の一実施例構成図、第２図〜第４図
Ａ〜Ｃは本考案の要部である回折手段の第１実施
例〜第３実施例図、第５図は第３図、第４図に示
す回折手段の調整を示す図、第６図は第４図Ｂに
示す圧電型アクチエータを駆動する配線状態を示
す図、第８図はデイスク上に照射されたセンター
ビーム及びサイドビームにより形成されたスポツ
ト光Ｓ，Ａ，Ｂと情報信号トラツクＴとの関係を
説明する図、第９図Ａ〜Ｃはオフセツト角度θが
所定値よりも大、所定値、所定値よりも小の場合
の２本のサイドビームの反射光を検出して得た２
つの検出信号Ｃ，Ｄ波形をそれぞれ示し、同図Ｄ
〜Ｆは同図Ａ〜Ｃに示した状態における検出信号
Ｃ，Ｄの差信号Ｃ−Ｄであるトラツキングエラー
信号波形をそれぞれ示す図、第１０図、第１１図
は光軸に対する回折格子の回折角度の調整が固定
式の光ピツクアツプの移送状態をそれぞれ説明す
る図である。１……光ピツクアツプ装置、１ａ……光ピツク
アツプ、２……光源、３……回折格子（回折手段
）、４……回折格子アクチエータ（調整手段）、
５……回転角度検出器（検出手段）、１５……Ｔ
Ｅアンプ（トラツキングエラー信号抽出手段）、
２６……デイスク（記録媒体）、Ｐ……トラツク
ピツチ、Ｔ……情報信号トラツク、Ｔ_１……走査
方向、θ……トラツクオフセツト角度。 FIGS. 1 and 7 are configuration diagrams of one embodiment of the optical pickup device of the present invention, and FIGS. 2 to 4 A to C show first to fourth embodiments of the diffraction means, which are the essential parts of the present invention. Figure 5 is a diagram showing the adjustment of the diffraction means shown in Figures 3 and 4. Figure 6 is a diagram showing the wiring state for driving the piezoelectric actuator shown in Figure 4B. The figure is a diagram explaining the relationship between the spot lights S, A, and B formed by the center beam and side beams irradiated onto the disk and the information signal track T. In FIGS. 9A to 9C, the offset angle θ is a predetermined value. 2 obtained by detecting the reflected light of the two side beams when the value is larger than, a predetermined value, and smaller than the predetermined value.
The waveforms of detection signals C and D are shown, respectively.
-F are diagrams showing the tracking error signal waveforms, which are the difference signals C-D of the detection signals C and D in the states shown in A to C of the same figure, respectively. FIG. 4 is a diagram illustrating the transport state of an optical pickup in which the diffraction angle is fixedly adjusted. 1... Optical pickup device, 1a... Optical pickup, 2... Light source, 3... Diffraction grating (diffraction means), 4... Diffraction grating actuator (adjustment means),
5...Rotation angle detector (detection means), 15...T
E amplifier (tracking error signal extraction means),
26...Disk (recording medium), P...Track pitch, T...Information signal track, _T1 ...Scanning direction, θ...Track offset angle.

Claims

[Scope of Claim for Utility Model Registration] A center beam for information signal reproduction and a side beam for tracking error correction are irradiated onto a recording medium in which information signal tracks are sequentially formed with a predetermined track pitch, and by this irradiation, tracking error signal extracting means for extracting a tracking error signal from reflected light corresponding to the side beam reflected from the recording medium; diffraction means for emitting light; detection means for detecting rotation of the diffraction means and outputting a first signal; and the first signal and the tracking error signal and light obtained from the tracking error signal extraction means. adjustment means for adjusting the rotation angle of the diffraction means with respect to the optical axis using a signal of a difference between a pickup and a second signal corresponding to a position allocation signal corresponding to a transfer position of the recording medium in the radial direction; and when the difference signal becomes zero, the operation of the adjusting means is stopped, thereby adjusting the track formed by the scanning direction of the center beam on the recording medium and the spot light formed by the irradiation of the side beam. An optical pickup device characterized in that the offset angle is always maintained at a predetermined value.