JPH0526257B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a beam shutter for optical pickup, and more particularly, a light beam passing hole is formed in a vertical plate constituting a U-shaped parallel plate spring, and the parallel plate spring is The vertical plate faces the emission surface of the semiconductor laser at a short distance from one end of the parallel plate, and the light beam passage hole extends in the longitudinal direction of the vertical plate with respect to the optical axis of the semiconductor laser. A magnetic shutter plate, which is fixed to the optical pick-up housing in a shifted manner and has a light beam passage hole formed therein, faces the emission surface of the semiconductor laser and aligns the light beam passage hole with the shutter plate. hand,
A linear electromagnetic drive section formed by winding a coil around a magnetic body fixed to the vertical plate and installed on the upper and lower surfaces of two permanent magnets to form a square frame-shaped permanently closed magnetic circuit is attached to the parallel plate spring. A part of the shutter plate and the emission surface of the semiconductor laser are disposed perpendicularly to the optical axis of the semiconductor laser so that the shutter plate and the emission surface of the semiconductor laser are disposed in the hollow part of the permanently closed magnetic circuit, and are fixed to an optical pickup housing. When the player is not in operation, the light beam passing hole is deviated from the optical axis of the semiconductor laser and blocks the light beam, and when the player is in operation, the electromagnetic force generated by the current in the coil causes the shutter plate to pass through the semiconductor laser. The present invention relates to a beam shutter for optical pickup, which is slid in a direction perpendicular to the optical axis to align the optical beam passing hole with the optical axis of the semiconductor laser and allow the optical beam to pass therethrough.

The beam shutter of a conventional optical pickup is
As shown in FIG. 1, it is placed between an objective lens A and a 90° polarizing mirror B. The beam shutter, as shown in FIG. A roughly F-shaped shutter frame 5 is disposed inside the pick-up housing 2, to which the blocking plate 1 is fixed, the other end is disposed outside the optical pick-up housing 2, and a roller is pivotally connected; is inserted into the pin 3, one end is fixed to one end of the shutter frame 5,
The other end consists of a torsion coil spring 7 fixed within the optical pickup housing 2. The roller 4 then comes into contact with a plate 7 provided on a player (not shown), and the optical pickup housing 2 moves along the plate 7.

When the player is operated, the plate 7 is pushed toward the optical pickup housing 2, and accordingly, the shutter frame 5 is pushed toward the optical pickup housing 2 via the roller 4 and rotates counterclockwise about the pin 3 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 player is inactive, 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. Therefore, 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 spring, E is a collimator lens,
F indicates a quarter-wave plate, and G indicates 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 space loss is therefore 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 has been made by focusing on the problems of the prior art. A shutter plate is disposed near the emission surface of a semiconductor laser, and the shutter is driven by a linear electromagnetic drive section in an optical pickup housing. By sliding the tar plate in a direction perpendicular to the optical axis of the semiconductor laser,
The purpose is to solve the above problems.

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, to explain the structure, reference numeral 10 is a U-shaped parallel plate spring, which is composed of parallel plates 10A and 10B parallel to the optical axis 11a of the semiconductor laser 11 and a vertical plate 10C perpendicular to the optical axis 11a of the semiconductor laser 11. ing. The light beam passage hole 10E is formed in the vertical plate 10C of the parallel plate spring 10 at a position offset from the center thereof. One end of the parallel plates 10A and 10B constituting the parallel plate spring 10 has a vertical plate 10C facing the emission surface of the semiconductor laser 11 at a short distance, and a light beam passage hole 10E facing the optical axis 11a of the semiconductor laser 11. The optical pickup housing 12 is shifted in the longitudinal direction of the vertical plate 11C.
It is fixed to the inner wall 12A with screws 13.
A passage hole 10D through which reflected light from the disk passes is bored in the parallel plate 10B disposed on the side where the optical sensor 14 is attached.

A ferromagnetic shutter plate 15 is smaller than the vertical plate 10C and is attached to the surface of the vertical plate 10C on the semiconductor laser 11 side. The shutter plate 15 is provided with a light beam passage hole 15A through which the light beam of the semiconductor laser 11 passes, and the size of the light beam passage hole 15A and the light beam passage hole 10E of the vertical plate 10C are equal, and the center thereof is are on the same line. The shutter plate 15 is arranged near the emission surface of the semiconductor laser 11.

16 is a permanently closed magnetic circuit in the shape of a rectangular frame, with rod-shaped permanent magnets 16A, 16B; permanent magnets 16A, 16B;
Rod-shaped magnetic bodies 16C, 16 installed on the upper and lower surfaces of
It is composed of D. The permanently closed magnetic circuit 16 includes the semiconductor laser 11 such that a portion of the parallel plates 10A and 10B, the vertical plate 10C, the shutter plate 15, and the emission surface of the semiconductor laser 11 are arranged in the hollow portion 16E of the permanently closed magnetic circuit 16. The optical pickup housing 12 is arranged perpendicular to the optical axis 11a and near the semiconductor laser 11, and is fixed to the base (not shown) of the optical pickup housing 12.

When the beam shutter is open, the parallel plate 10A
is in contact with the side surface of the permanent magnet 16A, and the permanent magnet 16
A acts as a stopper. Then, with the parallel plate 10A in contact with the side surface of the permanent magnet 16A, the center of the light beam passing hole 10E of the vertical plate 10C coincides with the optical axis 11a of the semiconductor laser 11, and the shutter plate 15 The position of the light beam passage hole 10E is determined so as to allow the eleven light beams to pass therethrough.

A coil 17 is wound around a part of the magnetic bodies 16C and 16D, and the direction of current flowing through the coil 17 is shown in FIG.

A linear electromagnetic drive section is formed by the permanently closed magnetic circuit 16 and the coil 17, and the shutter plate 15 linearly moves toward the permanent magnet 16A according to Fleming's left hand rule.

In Fig. 6, 18 is a polarizing beam splitter, 19 is a collimator lens, 20 is a quarter wavelength plate,
21 is a 90° deflection mirror.

Next, the action will be explained.

When the player is not operating, no current is flowing through the coil 17, so the shutter plate 15 is not subjected to electromagnetic force. Therefore, parallel leaf spring 1
The center of the vertical plate 10C of 0 coincides with the optical axis 11a of the semiconductor laser 11, and the light beam passage hole 10E of the vertical plate 10C and the light beam passage hole 15A of the shutter plate 15 are offset from the center of the vertical plate 10C. , the shutter plate 15 is the semiconductor laser 1
The beam shutter is in a closed state by blocking the light beam No. 1.

Next, when the player is operated, current flows through the coil 17, and the shutter plate 15 is moved by the permanent magnet 16A.
receives electromagnetic force on the side. Therefore, the parallel plate spring 10 integrated with the shutter plate 15 also receives a force from the permanent magnet 16A side, and the parallel plate 10 fixed to the inner wall 12A of the optical pickup housing 12
It moves toward the permanent magnet 16A using the other end of A, 10B as a fulcrum. The parallel plate 10A then comes into contact with the side surface of the permanent magnet 16A. In this state, the vertical plate 10
Since the light beam passing hole 10E of C and the light beam passing hole 15A of the shutter plate 15 are aligned with the optical axis 11a of the semiconductor laser 11, the light beam of the semiconductor laser 11 passes through the shutter plate 15 and the vertical plate 10C. The beam shutter will be open.

Next, to change the beam shutter from the open state to the closed state, the current in the coil 17 is cut off. Then,
The electromagnetic force that the shutter plate 15 was receiving disappears, and the force of the parallel leaf spring 10 causes the shutter plate 15 and the parallel leaf spring 10 to move around the permanent magnet 1.
It moves to the 6B side and the beam shutter becomes closed.

Since the shutter plate 15 is disposed near the emission surface of the semiconductor laser 11, the diameter of the light beam at the position of the shutter plate 15 is extremely small, so its operating stroke can be extremely small. Therefore, the space loss is extremely small, making it suitable for small optical pickups.

Furthermore, since there is no sliding part in this invention, reliability and durability are good.

As described above, in the present invention, a light beam passing hole is formed in a vertical plate constituting a U-shaped parallel plate spring, and one end of the parallel plate constituting the parallel plate spring is connected to the vertical plate. is fixed to the optical pickup housing so that the vertical plate faces the emission surface of the semiconductor laser at a short distance, and the light beam passage hole is shifted in the longitudinal direction of the vertical plate with respect to the optical axis of the semiconductor laser. A shutter plate made of a magnetic material and having a light beam passing hole formed therein is fixed to the vertical plate so as to face the emission surface of the semiconductor laser and the light beam passing hole is aligned with the light beam passing hole. A part of the parallel leaf spring, the shutter plate and The semiconductor laser is disposed perpendicularly to the optical axis of the semiconductor laser so that its emission surface is disposed in the hollow part of the permanently closed magnetic circuit, and is fixed to an optical pickup housing, so that when the player is not in operation, the light beam is The passage hole is deviated from the optical axis of the semiconductor laser and blocks the light beam, and when the player is operated, the shutter plate is slid in a direction perpendicular to the optical axis of the semiconductor laser by electromagnetic force caused by the current of the coil. By aligning the light beam passing hole with the optical axis of the semiconductor laser and allowing the light beam to pass through, the operating stroke of the shutter plate becomes extremely small, so space loss can be extremely reduced, and the compact optical The effect is that it can be applied to pickups.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the arrangement of a conventional beam shutter, Fig. 2 is an exploded perspective view of the conventional beam shutter, Fig. 3 is an exploded perspective view showing an embodiment of the present invention, and Fig. 4 is an exploded perspective view of the conventional beam shutter. FIG. 5 is a sectional view taken along the line AA in FIG. 4; FIG. 6 is a plan view of the beam shutter in an open state, showing an embodiment of the invention. It is. DESCRIPTION OF SYMBOLS 1...Shutoff plate, 2...Optical pick-up housing, 3...Pin, 4...Roller, 5...Shutter frame, 6...Torsion coil spring, 7
... Plate, 10 ... Parallel leaf spring, 11 ... Semiconductor laser, 14 ... Optical sensor, 15 ... Shutter plate, 16 ... Permanently closed magnetic circuit, 17 ...
…coil.

Claims (1)

[Claims] 1. A light beam passage hole is formed in a vertical plate constituting a U-shaped parallel plate spring, and one end of the parallel plate constituting the parallel plate spring is connected at a short distance between the vertical plate and the semiconductor laser emitting hole. The perpendicular plate is fixed to an optical pick-up housing so as to face the vertical plate, and has a light beam passage hole formed therein, facing the vertical plate and facing the vertical plate, and with the light beam passage hole being shifted in the longitudinal direction of the vertical plate with respect to the optical axis of the semiconductor laser. The magnetic shutter plate is
A permanently closed magnetic circuit in the shape of a rectangular frame is fixed to the vertical plate so as to face the emission surface of the semiconductor laser so that the light beam passage holes coincide with each other. A linear electromagnetic drive unit formed by winding a coil around the formed magnetic body is arranged such that a part of the parallel leaf spring, the shutter plate, and the emission surface of the semiconductor laser are arranged in the hollow part of the permanently closed magnetic circuit. The semiconductor laser is arranged perpendicularly to the optical axis of the semiconductor laser and fixed to the optical pickup housing, and when the player is not in operation, the light beam passing hole is deviated from the optical axis of the semiconductor laser and blocks the light beam, and the player During operation, the electromagnetic force generated by the current in the coil slides the shutter plate in a direction perpendicular to the optical axis of the semiconductor laser, aligns the light beam passage hole with the optical axis of the semiconductor laser, and transmits the light beam. Beam shutter for optical pickups that allows light to pass through