JPS6230180Y2 - - Google Patents

Description

[Detailed explanation of the invention] (1) Technical field of the invention This invention is a digital audio disk (hereinafter referred to as
Regarding optical pickups such as DAD),
In particular, the present invention relates to an optical pickup device in which the height of the entire optical pickup device can be adjusted.

(2) Prior Art Conventionally, in an optical pickup device used in a DAD or the like, a focus servo for aligning the focal position of an objective lens with a signal pit on a disk is usually constructed as shown in FIG. That is, as shown in FIG. 1, there is a hollow protrusion 4a in the center.
A ring-shaped magnet 3 is fixed to a disk-shaped lower yoke 4b having a ring shape, and an upper yoke 4d having a protrusion 4c on the outer periphery and a through hole 4e in the center is fixed on the magnet. The leaf spring 1 is stretched around the outer peripheral protrusion of the upper yoke 4d, and the winding frame 6 for the coil is suspended from the center of the leaf spring, and the coil 5 is wound around the winding frame, and the objective lens 2 is wrapped around the coil winding frame. The coil 5 is placed in the through hole 4e of the upper yoke, and the magnet 3 and the upper and lower yokes 4b, 4d are fixed to each other.
The optical pickup 8 is constructed in such a way that the position l between the disk 7 and the objective lens is changed by passing a current through the coil 5 within the magnetic field formed by the magnetic field.

Here, the focus signal changes as shown by the smallness arrow by the current flowing through the coil 5, but when the distance l between the objective lens 2 and the disk 7 deviates from the optimum value by B and moves farther away, the focus signal changes. The result will be as shown in Figure 2 A, and if only B does not reach the optimum value, the result will be as shown in Figure 2 B.
When focus servo is applied in such a state, a bias current corresponding to the deviation flows through the coil 5, causing the coil 5 to generate heat, which increases the temperature of the laser (not shown) and shortens the life of the optical pickup.

(3) Purpose of the invention The present invention was developed in view of the above-mentioned drawbacks, and it is possible to adjust the height of the entire optical pickup by adding an adjustment mechanism to the optical pickup device to optimize the focus error signal. The purpose of this invention is to obtain an optical pickup device with a

(4) Structure and operation of the device The above object is to fix a shaft rotatably fitted to a bearing mounted on a base to an arm via a shaft fixing part, and to attach a light beam to the opposite side of the pivot point of the arm. The pick-up is fixed, an adjustment screw is provided in the bearing that pivots against the shaft, and by rotation of the adjustment screw, the distance from the bottom of the base to the arm is adjusted, and the distance between the end face of the optical pickup device and the disk is adjusted. This is achieved by an optical pickup device that allows the distance between the two to be varied. Hereinafter, one embodiment of the present invention will be described in detail with reference to FIGS. 3 to 5.

FIG. 3 is a side view of the optical pickup device of the present invention, with a part of the cross section taken along a schematic line, and FIG. 4 is a plan view, in which an optical pickup device 8 having the same configuration as shown in FIG. The disk 7 and the end face of the optical pickup device 8 are fixed at a predetermined distance l from each other. The arm 9 has a shaft 10 rotatably attached to a bearing 12 mounted on a base 13. The shaft 10 is inserted into and fixed to a shaft fixing part 14 fixed to the arm 9, and the bearing 12 is inserted through a counterbore hole 14a of the shaft fixing part 14.
When the optical pickup device 8 rotates about the shaft 10 from the inner circumference (outer circumference) to the outer circumference (inner circumference) of the disk 7, the arm 9 is set so as to take an appropriate offset angle θ so as to be tangential to the track of the disk 7. (See Figure 4). Furthermore base 1
A shaft 10 inserted through a bearing 12 fixed on the base 13 is supported in a pivot bearing manner by an adjusting screw 15 screwed into the bearing 12 at the lower end of the base 13.
Reference numeral 16 denotes a U-shaped metal fitting fixed on the base 13, which has a plate spring 17 on the upper part, and presses one end of the shaft 10 to connect the arm 9, the optical pickup device 8, the shaft fixing part 14,
The shaft 10 is integrally biased toward the base 13.

In the above configuration, by rotating the adjustment screw 15 and adjusting the distance l between the objective lens of the optical pickup device 8 and the disk 7, the focus error output can be made as shown in FIG.

FIG. 5 shows another embodiment of the present invention, in which a bearing 18 is used between the shaft 10 and the bearing without using the U-shaped metal fitting 16 and the plate spring 17 to bias the arm 9 toward the base 13. An E-ring 19 is fitted to the lower end of the shaft, and a coil spring 20 is interposed between the E-ring and the bearing to press the arm 9 toward the base 13.

(5) Effects of the invention Since the invention is configured and operates as described above, it is possible to perform servo that does not include a bias value in the focus servo coil of an optical pickup device, thereby reducing the heat generation of the coil and the temperature rise of the laser. The practical effect is great.

[Brief explanation of the drawing]

Figure 1 is a side sectional view of a conventional optical pickup device, Figures 2A and 2B are focus error signal waveform diagrams caused by the distance between the objective lens and the disk of the optical pickup device shown in Figure 1, and Figure 3. 4 is a side sectional view of the main parts of the optical pickup device of the present invention, and FIG.
FIG. 5 is a side sectional view of a rotating part showing another embodiment of the present invention, and FIG. 6 is a focus signal waveform diagram obtained by the optical pickup device of the present invention. In the figure, 1 is a leaf spring, 2 is an objective lens, 3 is a magnet, 4a is a protrusion, 4b is a disc-shaped lower yoke, 4c is an outer peripheral protrusion, 4e is a through hole, 4d is an upper yoke, and 6 is a winding frame. , 7 is a disk, 8 is an optical pickup device, 9 is an arm, 10 is a shaft, 12 is a bearing, 13 is a base, 14 is a shaft fixing part, and 15 is an adjustment screw.

Claims (1)

[Scope of utility model registration request] A shaft rotatably fitted to a bearing mounted on a base is fixed to an arm via a shaft fixing part, and an optical pick-up is fixed to the opposite side of the arm from the rotational fulcrum, and the shaft is inserted into the bearing. An optical pickup device is provided with an adjustment screw that pivots against the disk, and the distance between the end face of the optical pickup device and the disk can be varied by adjusting the distance from the bottom of the base to the arm by rotating the adjustment screw. .