JPS59157223U - 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 1a is a schematic diagram showing an example of an optical pickup device capable of tracking servo and focus servo; Figure 1a is a pattern diagram of the light receiving surface of the photodetector in Figure 1;
Figures a and b are diagrams for explaining detection of tracking error signals and focus error signals; Figures 3a and b are diagrams for explaining detection of tracking error signals and focus error signals;
1 is a schematic diagram of an optical pickup device showing an embodiment of this invention, and a pattern diagram of its photodetector. In the figure, 1 is a laser light source, 2 is a PBS, 3 is a frimeter lens, 4 is a quarter wavelength plate, 5 is an objective lens, 6 is a photodetector, and 7 is a diffraction grating.

Claims (1)

[Scope of utility model registration request] An optical pickup device that detects return light completely reflected from a disk surface and performs at least focusing and tracking servo, which includes first and second photocathodes for detecting side spots of the return light, and a second photocathode for detecting a main spot. 3 photocathode are arranged, a tracking error signal is detected by the difference output of the signals detected by the first and second photocathode, and the third photocathode is divided into three in the track direction, and a central photocathode is formed. , an optical pickup device is characterized in that a focus error signal is detected by the differential output of signals detected by outer photocathodes on both sides thereof.