JPS59101041A - Beam shutter for optical pickup - Google Patents

Abstract

PURPOSE:To extremely minimize the operating stroke of a shutter rod so that the shutter rod can be adopted to a small-sized optical pickup, by sliding the shutter rod in the direction intersecting the optical axis of a semiconductor laser at right angle by the attracting force of an electromagnet in an optical pickup housing. CONSTITUTION:A shutter rod 10 is located near to the emitting surface of a semiconductor laser 11 so that the axial direction of the shutter rod 10 intersects the optical axis 11a of the semiconductor laser 11 at right angle. An electromagnet is composed of an iron core 13 and electromagnetic coil 14 and fitted to an optical pickup housing 12. When a player is operated, an electric current is made to flow through the electromagnetic coil 14 and the iron core 13 becomes an electromagnet and attracts the shutter rod 10 against the force of a coiled spring 15. Therefore, the shutter rod 10 is moved to the iron core 13 side. Accordingly, a light beam passing hole 10A coincides with the optical axis 11a of the semiconductor laser 11 and a shutter section 10B passes the light beam of the laser 11 and, therefore, a beam shutter is set to the open state.

Description

[Detailed Description of the Invention] The present invention relates to a beam shutter for optical pick-up, and in particular, one end thereof is inserted into a cavity of an electromagnet, and the end surface of the one end is in contact with the iron core of the electromagnet. A shutter rod that is in contact with one end of the coil spring, the other end of which is housed in a bored hole, and has a light beam passage hole bored in the middle part, is placed near the emission surface of the semiconductor laser to align it with the optical axis of the semiconductor laser. The invention relates to a beam shutter for optical pickup, which is disposed perpendicularly to the iron core, and slides the shutter rod P by suction of the one end to the iron core to allow the light beam of the semiconductor laser to pass through.

The beam shutter of a conventional optical pickup is arranged between an objective lens A and a 90° deflection mirror B, as shown in FIG. As shown in FIG. 2, the beam shutter consists of a blocking plate 1 that blocks the light beam, and a pin 6 whose middle part is fixed inside the optical pickup housing 2.
A blocking plate 1 is fixed to one end which is pivotally connected to the optical pickup housing 2 and arranged inside the optical pickup housing 2, and a roller 4 is pivotally connected to the other end which is arranged outside the optical pickup housing 2. Approximately A-shaped shutter frame 5. It consists of a torsion coil spring 6 which is inserted into the pin B, has one end fixed to one end of the shutter frame 5, and the other end fixed inside the optical pick-up haw and rung 2. Then, roller 4 plays the player (
(not shown), and the optical pickup nozzle 2 moves along the plate 7.

When the player operates, the plate 7 is pushed toward the optical pickup housing 2, and accordingly, the shutter frame 5 is pushed toward the shutter ring 2 via the roller 4 and rotates counterclockwise about the pin 6 as a fulcrum. . Therefore, the blocking plate 1 also rotates and the beam shutter opens.

Even if the optical pickup housing 2 moves, the roller 4 rolls along the plate 7, so the beam shutter remains open.

When the shutter 1/- is inoperative, the plate 7 returns to its original state, so the pressure contact between the plate 7 and the roller 4 is released, and the shutter frame 5 is rotated clockwise by the restoring force of the torsion coil spring 6. Accordingly, the blocking plate 1 also rotates and the beam shutter is closed.

In FIG. 1, C is a semiconductor laser, D is a polarizing beam splitter, E is a collimator lens, F is a quarter wavelength plate, and G is a disk.

In this prior art, the beam shutter is operated with the diameter of the light beam increasing as shown in FIG. 1, so the operating stroke is large and, as a result, the space loss is large. Although this is not a particular problem in large-sized optical pickups, it becomes a serious problem in small-sized optical pickups.

The present invention was made by focusing on the problems of the prior art.The shutter rod P is arranged near the emission surface of the semiconductor laser, and the shutter rod P is attracted by the electromagnet in the optical pickup housing. The purpose is to solve the above problems by sliding the semiconductor laser in a direction perpendicular to the optical axis.

The present invention will be explained below based on the drawings.

FIG. 3 to FIG. 6 are diagrams showing one embodiment of the present invention.

First, the configuration will be described. Reference numeral 10 denotes a shutter rod, and its axial direction is perpendicular to the optical axis 11a of the semiconductor laser 11, and the shutter rod is disposed near the emission surface of the semiconductor laser 11. The shutter rod 10 has a longitudinal section extending from a shutter portion 10B, which is the middle portion of a rectangular longitudinal section, and both ends of the shutter portion 10B, in which a light beam passing hole 10A through which the light beam of the semiconductor laser 11 passes is bored. It is composed of a circular one end portion 100 and the other circular end portion 10D.

One end portion 10C passes through a through hole 12A provided in the optical pick-up 12 and slides on the inner surface of the through hole 12A. The other end 10. D is housed in a borehole 12B provided in the optical pickup housing 12,
It slides on the inner surface of the bored hole 12B.

The centers of the through hole 12A and the bored hole 12B are on the same line.

The electromagnet consists of an iron core 16 and an electromagnetic coil 14, and is attached to the optical pick-up housing 12.

The iron core 16 is arranged outside the through hole 12A. Then, the iron core 16 is attached to the upper cover part 16B1 attached to the upper surface of the cylindrical part 13A, and to the lower surface of the cylindrical part 13A. It is composed of a lid part 13D. A guide hole 1 into which the tip of the guide portion 10E protruding from the end surface of the one end portion 100 is inserted into the center of the lower surface of the upper lid portion 13B.
3E has been caved in. The center of the iron core 16 is the through hole 12A.
, is on the same line as the center of the borehole 12B.

The electromagnetic coil 14 is fixed to the inner surface of the cylindrical portion 13A of the iron core 16. The lead wire of the electromagnetic coil 14 is taken out to the outside through a through hole (not shown) formed in the iron core 16, and is connected to a switch and a power source. A portion of the one end portion 10C and the guide portion 10E are arranged in the gap of the electromagnet, that is, in the hollow portion of the electromagnetic coil 14.

Reference numeral 15 denotes a coil spring, which is arranged around the guy P section 10E, and its both ends meet the lower surface of the upper lid section 10B and one end m1 (
It is in contact with the end face of 100.

When the coil spring 15 is stretched, the optical beam passing hole 10A is shifted and the shutter part 10B blocks the light beam of the semiconductor laser 11, and when the coil spring 15 is compressed, the light beam is Beam passage hole 1
The light beam passing hole 10A is positioned so that the center of the hole 0A coincides with the optical axis 11a of the semiconductor laser 11 and the shutter portion 10B allows the light beam of the semiconductor laser 11 to pass through.

In addition, in FIG. 6, 16 is a polarizing beam splitter;
7 is a collimator lens, 18 is a quarter wavelength plate, 19 is a 9
0° deflection mirror, 20 is a light sensor.

Next, the effect will be explained.

When the player is not operating, no current flows through the electromagnetic coil 14, so the iron core 13 does not act as an electromagnet and does not attract the shutter rod P10. Therefore, the shutter rod '10 is pushed toward the borehole 12B by the force of the coil spring 15. Therefore, the light beam passage hole 10A is shifted from the optical axis 11a of the semiconductor laser 11, and the shutter part 10B blocks the light beam of the semiconductor laser 11, so that the beam shutter is in a closed state.

Next, when the player operates, current flows through the electromagnetic coil 14, the iron core 1 becomes an electromagnet, and the coil spring 15
Suction the shirt tarotsu 110 against the force of. Therefore, the shutter rod 10 moves toward the iron core 16 side. Therefore, the light beam passing hole 10A is aligned with the optical axis 11a of the semiconductor laser 11, and the shutter part 10B is aligned with the optical axis 11a of the semiconductor laser 11.
The beam shutter is in an open state, allowing one light beam to pass therethrough.

Next, in order to change the beam shutter from the open state to the closed state, the current in the electromagnetic coil 14 is cut off. Then, the suction state of the shutter rod 10 is released, and the force of the coil spring 15 moves the shutter rod 1510 toward the borehole 12B, and the beam shutter becomes closed.

Since the shutter rod 10 is arranged near the emission surface of the semiconductor laser 11, the diameter of the light beam at the position of the shutter rod P10 is extremely small, and therefore its operating stroke can be extremely small. Therefore, the space loss is small, and it is suitable for small-sized optical pickups.As explained above, in this invention, one end is inserted into the cavity of the electromagnet, and the end face of the one end is connected to the iron core of the electromagnet. A shutter rod, which is in contact with one end of the coil spring that is in contact with the semiconductor laser and whose other end is housed in a bored hole and has a light beam passage hole in the middle part, is placed near the emission surface of the semiconductor laser. By arranging the shutter rod perpendicularly to the optical axis of the hoop and sliding the shutter rod by suction of the one end to the iron core, the operating stroke of the shutter rod becomes extremely small.
This has the advantage that space loss can be extremely reduced, and it can also be applied to small-sized optical pickups.

[Brief explanation of drawings]

Figure 1 shows the arrangement of a conventional beam shutter, Figure 2 shows the arrangement of a conventional beam shutter.
3 is an exploded perspective view of a conventional beam shutter, FIG. 3 is an exploded perspective view of an embodiment of the present invention, FIG. 4 is a plan view of an embodiment of the invention in the beam shutter open state, and FIG. 5 is an exploded perspective view of a conventional beam shutter. 4 is a sectional view taken along the line A-A in FIG. 4, and FIG. 6 is a plan view of the beam shutter in a closed state, showing an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Shutoff plate, 2... Optical pick anzino 1 housing, 6... Pin, 4... Roller, 5... Shutter frame, 6... Torsion coil spring, 7...
Play 4.10...Shutter rod, 11...Semiconductor v-f, 13...Iron core, 14...Coil, 15...
...Coil spring patent applicant Akai Electric Co., Ltd. Figure 1 Figure 2 Figure 4

Claims (1)

[Claims] 1. A shutter rod P whose axial direction is perpendicular to the optical axis of the semiconductor laser and a light beam passage hole is bored in the middle part is arranged near the emission surface of the semiconductor laser, and one end of the shutter rod A coil spring is inserted between the end face of one end of the shutter rod and the iron core of the electromagnet, and the other end of the shutter rod is inserted into the gap of the electromagnet attached to the optical pickup housing. Beam shutter for optical pickup housed in a hole provided in the optical pickup housing