JPH08112940A - Light source device - Google Patents

Abstract

PURPOSE: To integrate the lens holder and optical iris of a collimator lens. CONSTITUTION: A collimator lens 3 is held to a lens holder 7 having a transparent cylindrical part 7a and the lens holder 7 is bonded to a mirror cylinder 2 by curing the UV curable adhesive 8 between the cylindrical part 7a and the mirror cylinder 2 holding semiconductor laser. The lens holder has a opaque part constituting an optical iris 4 and is molded by two-color molding mixing a dye with a part of a transparent material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light source device such as a scanning optical device used in an image forming apparatus such as a laser beam printer or a digital copying machine.

[0002]

2. Description of the Related Art A scanning optical device used in an image forming apparatus such as a laser beam printer, a laser facsimile or a digital copying machine will be described with reference to FIG. The scanning optical device of FIG. 4 includes a light source unit E that emits a laser beam L _0.
0 and a rotary polygon mirror R that deflects and scans the laser light L _{0. The} laser light deflected and scanned by the rotary polygon mirror R is passed through an imaging lens F and a folding mirror M to a photoconductor on a rotating drum (not shown). Form an image. The laser light imaged on the photoconductor forms an electrostatic latent image by main scanning by rotation of the rotary polygon mirror R and sub-scanning by rotation of the rotary drum.
Further, a part of the laser beam deflected and scanned by the rotary polygon mirror R is introduced into the scanning start signal detector D by the detection mirror B, and the light source unit E ₀ is scanned by the scanning start signal detector D.
The write modulation is started by the output signal of. The light source unit E ₀ , the rotary polygon mirror R, the imaging lens F, the detection mirror B, the scanning start signal detector D, the folding mirror M, etc. are attached to the optical box H, and the upper opening of the optical box H is a lid (not shown). Is blocked by.

As shown in FIG. 5, the light source unit E ₀ includes a circuit board 103 on which a laser driving circuit is mounted, a lens barrel 104a having a collimator lens 104 inside, a lens barrel holder 104b for holding the lens barrel 104a, and a metal member. The unit is composed of the base 103a and the semiconductor laser 101, but after these are assembled as a unit, the optical box H
It is fixed to the outer surface of the side wall by screws or the like.

The semiconductor laser 101 is fixed to a base 103a made of metal together with the circuit board 103, and then fixed to a lens barrel holder 104b having a collimator lens 104 inside by screws or the like. The lead pins 101a to 101c of the semiconductor laser 101 penetrate the circuit board 103 from the inner surface 103c toward the outer surface 103b, and the outer surface 10
It is soldered to the connection wiring printed on 3b. On the outer surface 103b of the circuit board 103, various electronic components (not shown) of a laser drive circuit for driving the semiconductor laser 101 to emit the same are mounted, and the semiconductor laser 101 includes the lead pins 101a to 101c and the above-mentioned connection. It is connected to these electronic parts via wiring.

Laser chip 101 of semiconductor laser 101
Focusing of the laser light generated from d and the collimator lens 104 is performed by sliding the lens barrel 104a in the cylindrical portion 104c of the lens barrel holder 104b in the optical axis direction of the laser light, and the fixation is fixed. Instant adhesive is dropped on the sliding surface. The collimator lens 104 and the optical axis of the laser beam are aligned by adjusting the mounting position of the base 103a with respect to the lens barrel holder 104b, and the fixation thereof is performed by the screws or the like as described above.

[0006]

However, according to the above-mentioned prior art, when the collimator lens is assembled, the lens barrel holding the collimator lens is aligned with the optical axis and then focused, and then the lens barrel holder is fixed with an instant adhesive. Since it adheres to the collimator lens, the volatile component of the instant adhesive may contaminate the collimator lens.
In addition, the position of the optical axis and the focal position of the collimator lens may be displaced due to the displacement of the lens barrel due to the injection of the instant adhesive.

In addition to the collimator lens, the lens barrel and the lens barrel holder for holding the collimator lens, an optical diaphragm for narrowing the laser beam collimated by the collimator lens to a predetermined beam diameter is provided downstream of the collimator lens. However, there is an unsolved problem that the light source device has a large number of parts to be assembled and the assembly process is complicated.

The present invention has been made in view of the above-mentioned unsolved problems of the prior art, and it is easy to assemble a collimator lens and an optical diaphragm, and the number of assembling parts is small. It is an object of the present invention to provide a light source device capable of significantly reducing an assembly error.

[0009]

In order to achieve the above object, the light source device of the present invention comprises a light source supported by a light source supporting means and a lens holder for transmitting light for curing a photo-curing adhesive. It has at least one optical lens assembled to the light source supporting means by a member, and at least a part of the lens holding member is made of a material that blocks the illumination light generated from the light source. .

Further, it is preferable that a part of the lens holding member constitutes an optical diaphragm for narrowing the illumination light to a predetermined beam diameter.

The lens holding member may have a body portion made of a transparent material and an opaque portion made of a colored material.

The lens holding member may be made of a material that transmits the light for curing the photo-curing adhesive and blocks the illumination light.

[0013]

Since the lens holding member is adhered to the light source holding means such as the lens barrel by a photo-curing adhesive such as an ultraviolet-curing adhesive, no trouble occurs when using an instant adhesive. There are few assembly errors.

Further, since at least a part of the lens holding member is made of a material which blocks the illumination light, by using this part as, for example, an optical diaphragm, the number of assembling parts of the light source device is greatly reduced and the assembling process is simplified. Can be converted.

If the lens holding member is formed by two-color molding of a transparent material and an opaque material, the assembling process is simple and the increase in manufacturing cost can be avoided.

Further, if the entire lens holding member is made of a material which transmits the light for curing the photo-curing adhesive and blocks the illumination light, the molding process is further simplified.

[0017]

Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic sectional view showing a light source device E ₁ of a scanning optical device according to the first embodiment, which is a semiconductor laser 1 which is a light source for generating a laser beam L ₁ which is illumination light, It has a lens barrel 2 which is a light source supporting means for supporting the same, a collimator lens 3 which is an optical lens for collimating the laser light L ₁ , and an optical diaphragm 4 which is arranged downstream thereof.
The semiconductor laser 1 is fixed in the center hole 2a of the lens barrel 2 by a known method such as press fitting, and the lens barrel 2 has its flange portion 2b fastened to the side wall of the optical box 6 with a screw 5.

The circuit board 1a on which the drive circuit for the semiconductor laser 1 is mounted has a through hole 1b through which the screw 5 passes.
It is fastened to the lens barrel 2 with a screw (not shown).

The collimator lens 3 is held by a lens holder 7 which is a lens holding member, and the lens holder 7 has a cylindrical portion 7a which is a main body portion made of a transparent material and which has a cylindrical portion 7a. After covering the tubular portion 2c of the lens barrel 2 with the optical axis of the collimator lens 3 and focusing, the UV curable adhesive 8 previously applied to the tubular portion 2c of the lens barrel 2 is whitened. It is adhered to the lens barrel 2 by being cured by the ultraviolet rays shown by the extraction arrow A.

As described above, the lens holder 7 has the transparent cylindrical portion 7a and the opaque portion 7b which constitutes the optical diaphragm 4 for narrowing the laser light to a predetermined beam diameter, and is made of acrylic, polycarbonate, or the like. It is integrally molded using a transparent resin, and is manufactured by so-called two-color molding in which only a few percent of a coloring agent, for example, carbon is mixed in only the opaque portion 7b at the time of molding.

A transparent material other than the above-mentioned transparent resin may be used as the material of the lens holder 7 as long as it transmits light for curing the photo-curing adhesive.
It goes without saying that the opaque portion 7b can also be obtained by injecting an opaque resin that blocks the laser beam only into a predetermined portion of the molding die.

Generally, the outer diameter of the cylindrical portion 2c of the lens barrel 2 is set to be smaller than the inner diameter of the cylindrical portion 7a of the lens holder 7 by about 1 mm, and the optical axis alignment of the collimator lens 3 is performed by the lens barrel 2. This is performed by moving the lens holder 7 in the direction perpendicular to the optical axis of the laser beam L ₁ within a range allowed by the size of the gap formed between the cylindrical portion 2c and the cylindrical portion 7a of the lens holder 7, Further, the focusing of the collimator lens 3 is performed by moving the cylindrical portion 7 a of the lens holder 7 to the lens barrel 2.
It is carried out by sliding in the axial direction on the cylindrical portion 2c.

As described above, the laser light collimated by the collimator lens 3 and narrowed to a predetermined beam diameter by the optical diaphragm 4 is linearly condensed on the reflecting surface of the rotary polygon mirror by a cylindrical lens (not shown), The light is deflected and scanned by the rotary polygon mirror, and an image is formed on the photoconductor of the rotary drum through an imaging lens and the like. The laser light imaged on the photoconductor is
An electrostatic latent image is formed by main scanning by rotation of the rotary polygon mirror and sub-scanning by rotation of the rotary drum.

Although the ultraviolet curable adhesive is used in this embodiment, it goes without saying that a photocurable adhesive other than the ultraviolet curable adhesive may be used.

According to the present embodiment, a part of the lens holder for assembling the collimator lens to the lens barrel of the semiconductor laser is transparent, and the lens holder is UV-curable by the ultraviolet rays transmitted through the transparent part and irradiated. Since the adhesive is fixed to the lens barrel by being hardened, there is no possibility that the collimator lens is contaminated by the volatile component of the adhesive as in the case of using the instant adhesive.

Further, the uncured UV-curable adhesive is applied to the cylindrical portion of the lens barrel in advance, the optical axis of the collimator lens is adjusted and the focus is adjusted, and then the adhesive is cured by irradiating UV rays. Therefore, the work of aligning the optical axis and focusing of the collimator lens is easy and the accuracy thereof is greatly improved.

In addition, since the lens holder has an opaque portion formed by two-color molding, and this constitutes an optical diaphragm, it is assembled as compared with the case where the optical diaphragm is individually manufactured and assembled in an optical box or the like. The number of parts is greatly reduced and the assembly process is greatly simplified.

As a result, an inexpensive and high-performance light source device can be realized.

FIG. 2 is a schematic cross-sectional view showing a modification of the first embodiment, which is similar to the lens holder 7 in the opaque portion 17b of the lens holder 17 and the collimator lens 1 is provided.
3 is held, and an optical diaphragm 14 is arranged on the upstream side of the collimator lens 13.

The collimator lens 13 is attached to the lens holder 17
It has the advantage that it can be assembled from the end face on the downstream side of.

FIG. 3 is a schematic sectional view showing a light source device E _{2 according} to the second embodiment. This is a substitute for the two-color molding lens holders 7 and 17 according to the first embodiment and its modification.
The lens holder 27 is made of a material that does not transmit laser light but transmits light that cures a photo-curing adhesive, for example, only ultraviolet light.

The lens holder 27 holds the collimator lens 23 on the end face on the downstream side along the laser beam L _1, and has an inner diameter reducing portion 27b which constitutes an optical diaphragm 24 on the upstream side of the collimator lens 23.

As a material which blocks laser light and transmits ultraviolet rays, it is preferable to use a transparent resin such as acrylic or polycarbonate mixed with a dye that transmits only ultraviolet rays, for example, a dye used for a colored glass filter or the like.

Since the semiconductor laser 1, the circuit board 1a, the optical box 6, the adhesive 8 and the like are the same as those in the first embodiment, they are designated by the same reference numerals and their description is omitted.

The present embodiment has an advantage that the manufacturing process of the lens holder is simple because it is not necessary to perform two-color molding when molding the lens holder. Other points are the same as the first embodiment.

[0037]

Since the present invention is configured as described above, it has the following effects.

The collimator lens assembly error is small, the collimator lens and the optical diaphragm are easily assembled, and the number of assembly parts is small.

As a result, an inexpensive and high-performance light source device can be realized.

By using such a light source device, it is possible to greatly contribute to cost reduction and high performance of the image forming apparatus and the like.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing a light source device according to a first embodiment.

FIG. 2 is a schematic cross-sectional view showing a modified example of the first embodiment.

FIG. 3 is a schematic sectional view showing a light source device according to a second embodiment.

FIG. 4 is a perspective view showing an entire scanning optical device.

FIG. 5 is a schematic cross-sectional view showing a light source device according to a conventional example.

[Explanation of symbols]

 1 semiconductor laser 2 lens barrel 3,13,23 collimator lens 4,14,24 optical diaphragm 6 optical box 7,17,27 lens holder 8 adhesive

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location H04N 1/04 101

Claims (4)

[Claims] 1. A light source supported by the light source support means, and at least one optical lens assembled to the light source support means by a lens holding member that transmits light for curing a photocurable adhesive. However, at least a part of the lens holding member is made of a material that blocks the illumination light generated from the light source. 2. The light source device according to claim 1, wherein a part of the lens holding member constitutes an optical diaphragm for narrowing the illumination light to a predetermined beam diameter. 3. The light source device according to claim 1, wherein the lens holding member has a body portion made of a transparent material and an opaque portion made of a colored material. 4. The light source device according to claim 1, wherein the lens holding member is made of a material that transmits light for curing the photo-curable adhesive and blocks illumination light.