JPS6344811Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a collimator lens barrel for a laser unit using a semiconductor laser, such as a laser beam printer.

For example, a conventional laser unit has a configuration as shown in Fig. 1, and this can be briefly explained as follows.
The semiconductor laser is enclosed in a laser package 1 sealed with dry nitrogen gas, and this laser package 1 is fixed to a laser support member 2 with machine screws or the like. Attached to the laser support member 2 are a temperature control means 3 such as a heater for controlling the semiconductor laser at a constant temperature, a printed board 4, and a protective cover 5. On the other hand, a collimator lens for collimating the laser beam emitted from the semiconductor laser is comprised of several spherical lenses and is housed in the lens barrel 6. A thread is cut on the outer diameter of this lens barrel 6, and after adjusting the optical axis direction, it is fixed to a holder 8 with a lock nut 7. Further, the holder 8 is fixed on the surface of the laser support member 2 with a machine screw or the like after adjustment in a direction perpendicular to the optical axis direction.

Considering the adjustment of the collimator lens in the optical axis direction, the collimator lens is rotated by twisting the lens barrel 6, the collimator lens is moved in the optical axis direction, and the positions of the collimator lens and the laser emitting part are adjusted. However, the screw gap is about 100 μm even when using JIS class 1 screws, and the surface of the screw thread is not smooth, so when tightening with the lock nut 7, the lens barrel 6 tilts irregularly. However, the alignment between the collimator lens and the laser emitting section has an accuracy of several μm or less, and the inclination of the lens barrel 6 makes adjustment extremely difficult.

The present invention aims to solve this problem and provide a laser unit that is easy to adjust.

To achieve the above object, the present invention includes a semiconductor laser and
a collimator lens that converts the laser light emitted from the semiconductor laser into parallel light; and a cylindrical member having a cylindrical portion that supports the collimator lens.
In the laser unit having a holder having a fitting hole provided along the optical axis direction for holding the tubular member inside, the tubular member is characterized in that it has a magnetic portion at least at the tip on the laser light emission side that can be attracted by a magnet.

Hereinafter, an embodiment of the present invention will be described using FIG. 2. FIG. 2 is a longitudinal sectional view showing an embodiment of the present invention. Although this invention uses a fiber lens (a rod lens whose refractive index changes in a parabolic curve in the radial direction), which has a greater effect, a conventional collimator lens using several spherical lenses can also have a great effect. . The fiber lens 9 is fitted on the inner surface, and the outer surface has a gap of several μm.
A hollow circular tube-shaped lens barrel 6 that fits with the
Magnetic material is used in some parts.

In the case of the fiber lens 9, the parallelism between the optical axis and the outer diameter is very accurate.
As shown in Fig. 4, if the slot 6a is inserted into the lens barrel 6 and the fiber lens 9 is lightly press-fitted, the parallel deviation between the outer surface of the lens barrel 6 and the optical axis will be kept at a very high level of several μm or less. be able to. The outer surface of the lens barrel 6 and the holder 8 are fitted with a gap of several μm, and the optical axis direction can be adjusted by attaching the lens barrel 6 to a magnet held movably in the optical axis direction, and moving the magnet to adjust the optical axis direction. If the method of adjusting the barrel 6 is used, the lens barrel 6 will move smoothly with almost no inclination. And after the position is given,
Adjustment is easily completed by pouring adhesive into the hole 8' formed in the holder 8 and fixing the lens barrel 6. Furthermore, in the case of the fiber lens 9, aperture is necessary because the aberration is large at the periphery.
The diaphragm 10 may be made of a magnetic material and attached to the output side as shown in FIG. In this case, it is preferable to provide a taper in the optical axis direction so that it can be easily press-fitted into the aperture 10 and to prevent the collimated laser light from being reflected by the aperture 10 and returning to the light emitting section and disturbing the laser light emission. Alternatively, as shown in FIG. 6, a lens barrel 6 made of a magnetic material may be formed by drilling the inner diameter of the lens barrel to form a taper and an integrated aperture. Furthermore, when a spherical lens is used, the retaining ring or diaphragm on the exit side may be made of a magnetic material. Further, as shown in FIG. 7, a magnetic body 11 such as an iron piece may be attached to the lens barrel 6.

As described above, in the laser unit, the cylindrical member having the cylindrical part that supports the collimator lens has a magnetic part that can be attracted by a magnet at least at the tip on the laser beam emission side, so that the inclination of the optical axis of the lens can be reduced. Since it can be reduced, the aberration of the lens can be reduced. Also, the lens barrel may tilt when adjusting or fixing.
Since it does not move irregularly, adjustments can be made very easily and in a short time. Furthermore, since the configuration is simple, an inexpensive laser unit can be provided.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing a conventional example, FIG. 2 is a longitudinal sectional view showing an embodiment of the present invention, FIGS. 3 and 4 are a longitudinal sectional view and a side view showing the lens barrel of FIG. 2, FIG. 5 is a longitudinal sectional view showing another embodiment of the invention, FIG. 6 is a longitudinal sectional view showing still another embodiment of the invention, and FIG. 7 is a longitudinal sectional view showing another embodiment of the invention. It is a diagram. DESCRIPTION OF SYMBOLS 1... Laser package, 2... Laser support member, 3... Temperature control means, 4... Printed board, 5...
Protective cover, 6... Lens barrel, 7... Lock nut,
8...Holder, 9...Fiber lens, 10...
Aperture, 11...Magnetic material.

Claims (1)

[Claims for Utility Model Registration] 1. A semiconductor laser, a collimator lens that converts laser light emitted from the semiconductor laser into parallel light, a cylindrical member having a cylindrical portion that supports the collimator lens, and In a laser unit having a holder having a fitting hole provided along the optical axis direction for holding the cylindrical member inside, the cylindrical member has a magnet at least at the tip on the laser beam output side. A laser unit characterized by having a magnetic part that can be attracted. 2. The laser unit according to claim 1, wherein the cylindrical member has a lens barrel that supports a collimator lens and a diaphragm for the collimator lens, and the diaphragm is made of a magnetic material. 3. The laser unit according to claim 1, wherein the cylindrical member has a lens barrel that supports a collimator lens and a holding ring on the emission side, and the holding ring is made of a magnetic material. .