JPS59157222U - Optical pickup device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Brief explanation of the drawing]

Figure 1 a and b are the tiger tsuking servo and four forces.
. A schematic diagram showing an example of an optical pickup device capable of servo control and a diagram showing a pattern of the photocathode of a photodetector, Figure 2a
, b are diagrams showing the spot position in the case of a focus error signal, and Figures 3a and b are schematic diagrams of an optical pick-up device showing an embodiment of this invention. 4a and 4b are characteristic diagrams of the detection signal, and FIG. 5 is a diagram showing the pattern of the photocathode showing another embodiment of this invention. In the figure, 1 is a laser light source, 2 is a PBS, 3 is a collimator lens, 4 is a 1-wavelength plate, 5 is an objective lens, 6 is a photodetector, and 8 is a diffraction grating.

Claims (1)

[Scope of utility model registration request] In an optical pickup device that detects return light reflected from a disk surface and performs at least focusing and tracking servo, first and second photoelectric surfaces for detecting side spots of the return light; A third photocathode for spot detection is arranged, a tracking error signal is detected by the difference output detected by the first and second photocathode, and the center of the third photocathode is divided into three in the radial direction. An optical pickup device characterized in that a focus error signal is detected by a difference output between a signal detected by a photocathode and an outer photocathode provided at both ends of the photocathode.