JPH08184735A - Light source unit - Google Patents

Abstract

PURPOSE: To provide the light source device which consists of a small number of constituent components, has no possibility of a position shift at the time of its manufacture, facilitates the automation of assembly adjustments, and enables the use of an ultraviolet-ray setting adhesive, and is inexpensive, high in precision, and highly flexible. CONSTITUTION: The light source unit is constituted by fixing a holding part 15 which has a penetrating fitting hole in the center, a semiconductor laser 13 which is fitted in the fitting hole 15a, a printed circuit board 9 which is electrically connected to the semiconductor layer 3 and fixed to the holding part 15, a collimator lens 8 which has a reference surface 15f parallel to an optical axis and is held at the holding part 15, an aperture 16 which adjusts laser light emitted by the collimator lens 8, and a holding structure for the collimator lens 8 by using the ultraviolet-ray setting type adhesive.

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 using a semiconductor laser used in a digital copying machine, a laser printer or the like.

[0002]

2. Description of the Related Art In a light source device using a semiconductor laser, the directionality (optical axis characteristic) of laser light emitted from the device and the parallelism (collimate characteristic) of a light beam are required as its optical characteristics. For this reason, the light source device usually adjusts the relative position of the light emitting point of the semiconductor laser and the collimator lens in three axes (x, y, z directions), and the positional accuracy is required to be micron or less. ing.

Therefore, a light source having a semiconductor laser and a collimator lens must be constructed so that it can be adjusted in the three axial directions and fixed at the adjusted position. When the collimator lens is fixed with an adhesive, the required positional accuracy in the z direction (optical axis direction) is particularly high, so it is desirable that the collimator lens be configured so that the contraction direction does not occur in the z direction. Therefore, the adhesive layer is usually set in a direction substantially parallel to the optical axis (direction parallel to the z axis).

A conventional light source device (Japanese Patent Laid-Open No. 5-88061).
(See Japanese Patent Laid-Open Publication) will be described with reference to the vertical sectional view of FIG. As shown in FIG. 3, a semiconductor laser 3 for irradiating a laser beam is press-fitted and fixed in a stepped hole 2 provided in a base 1. The flange 5 attached to the base 1 with the two screws 4 is provided with a fitting hole 6 facing the stepped hole 2, and the left side portion of the fitting hole 6 is 0.1 mm thicker than the fitting hole 6.
An inlet portion 6a having a relatively large diameter is formed.

The fitting hole 6 has a clearance of 0.01 to
A cylindrical lens holder 7 having a thickness of 0.03 mm is fitted therein, and a collimator lens 8 for converting a laser beam into a substantially parallel light flux is held in the lens holder 7. The guide pin 11 protruding from the end face of the base 1 is fitted into the positioning hole 10 provided in the printed board 9, and the tip portion of the guide pin 11 is thermally deformed to fix the printed board 9 to the base 1. The lead wire 12 of the semiconductor laser 3 is soldered to the conductive pattern portion of the printed board 9.

The flange 5 is provided with a notch 13 connected to the inlet portion 6a, and the notch 13 is adjusted after the light source of the semiconductor laser 3 is aligned with the focal position of the collimator lens 8 (adjustment in the z-axis direction). The lens holder 7 is fixed by infiltrating the adhesive flowing in from the inlet 6a. The screw 4 is loosened before fixing the lens holder 7, and the screw 4 is adjusted after the light emitting point of the semiconductor laser 3 is aligned with the optical axis of the collimator lens 8 (adjustment in the x and y axis directions). Is tightened to fix the flange 5 to the base 1.

The aperture forming member 14 transmits the collimator lens 8 and forms an aperture 14a for forming a laser beam which becomes a substantially parallel light beam, and a notch 13 in the flange 5.
To form a protrusion 14b corresponding to
3 and the aperture forming member 14 is fixed.
When this light source device is attached to a main body of a digital copying machine or a laser printer, a reference plane is a plane 5a perpendicular to the optical axis of the flange 5, and the optical characteristics are also adjusted with reference to the plane 5a.

In the light source device of FIG. 4, a lens barrel 26 to which a collimator lens 8 is fixed is inserted into a holder 23, and a base 24 to which a substrate 25 on which a semiconductor laser 3 is mounted is fixed is a claw-shaped projection of the holder 23. 23d, holder 2
Adhesive is injected from the grooves 23a and 23b and the hole 23c of No. 3 to fix the base 24 and the lens barrel 26 to the holder 23. This type of light source device is disclosed in Japanese Patent Laid-Open No. 5-136952.
The light source device is disclosed in Japanese Patent Laid-Open No. 5-2733483.

[0009]

The conventional light source device as described above has the following problems. (1) Since the x- and y-direction adjustment (optical axis characteristic adjustment) section and the z-direction adjustment (collimation characteristic, that is, focus direction adjustment) section are separate mechanisms, the number of components of the light source device is large. However, there is a drawback that the product becomes expensive. Further, since the accuracy of the required fitting of the outer diameter of the lens holder 7 and the inner diameter of the fitting hole 6 of the flange 5 becomes high, there is a problem that the manufacturing cost of both parts also becomes high.

(2) Since the screw 4 is tightened and the flange 5 is fixed to the base 1 after the adjustment in the x and y directions, when the screw 4 is tightened, the screw seat on the end face of the base 1 and the flange The biting of No. 5 may cause misalignment in the x and y directions, and the accuracy of the laser directionality (optical axis characteristic) may be low.

(3) The laser light of the semiconductor laser used in the light source device has a constant spread angle, and not all the laser light is incident on the collimator lens 8. The semiconductor laser has a legal standard from the viewpoint of safety for the human body, and it is desirable that the laser light of the semiconductor laser does not leak outside the direction other than the optical axis direction. This is the same not only during use but also during adjustment in the manufacturing process. The flange 5 and the base 1 need to be made of a material that prevents laser light from leaking to the outside. Light must not be transmitted. By the way, current semiconductor lasers are mainly infrared and red light, which are low cost).

On the other hand, the adhesive used for fixing the collimator lens 8 is an ultraviolet curable adhesive which can be optionally cured in a short time, which is advantageous for shortening the production tact time.
It is also highly reliable. However, JP-A-5-88061
JP-A-5-136952, JP-A-5-27348
In the configuration described in the publication No. 3, when the flange or the holder is made of a material through which ultraviolet rays do not pass, even if the ultraviolet rays are radiated through the gap filled with the ultraviolet curable adhesive, the entire adhesive cannot be evenly radiated and the adhesive is cured. Since unevenness and an uncured portion occur and curing of the uncured portion is delayed, problems such as positional displacement and cracking of the fixed object occur.

Materials that do not transmit infrared rays and red light are
Normally, it does not transmit light of wavelengths shorter than that, and therefore does not transmit ultraviolet light. If only the ultraviolet region is transmitted, there is a problem that a special filter is added or a special coating is applied to the flange itself, resulting in a significant increase in cost. Therefore, an ultraviolet curable adhesive cannot be used as an adhesive for fixing the collimator lens.

(4) Collimator lens 8 in the light source device
Focus position adjustment (adjustment in the z direction) of the aperture 14a.
The parallelism (collimation characteristic) of the emitted laser light flux formed by is detected and adjusted. In general, a light flux that has passed through the aperture 14a tends to spread due to the diffraction phenomenon of light, so that the parallelism of the light flux changes with and without the aperture 14a. Due to the difference in individual characteristics of the semiconductor laser 3, the degree of change also varies.

Further, the parallelism of the laser light flux required in the light source device is a characteristic of the light flux in the range emitted from the aperture 14a, and the light passing near the outer circumference of the collimator lens 8 is unnecessary. Around the outer circumference of the collimator lens 8, the influence of aberration is large, and the lens performance of the collimator lens 8 varies widely. Therefore, even if the parallelism is detected by the characteristics of the entire light flux and the required accuracy is satisfied, there are cases where the light flux near the center is not satisfied.

For the above reasons, it is ideal that the focus position of the collimator lens is adjusted with the aperture forming member 14 attached. However, in the configuration disclosed in Japanese Patent Laid-Open No. 5-88061, the collimator lens 8 is not used. Since the aperture forming member 14 covers, the position of the collimator lens 8 cannot be adjusted with the aperture 14a attached, and the parallelism of the laser light flux varies after the aperture 14a is attached.

(5) When the light source device is attached to the main body of a copying machine or a printer, it is general to fix the reference surface of the flange with screws, but depending on the requirements of the main body, it may be fixed by screwing from above or from the side. It may be fixed by tightening screws.

In the structure described in Japanese Patent Laid-Open No. 5-88061, since the reference surface of the flange 5 is perpendicular to the outgoing optical axis, the structure is attached only from the side, and the mounting from above is required. In this case, there is a problem that an intermediate mounting member is required, the cost becomes high, and the accuracy of the intermediate mounting member is disadvantageous in the accuracy of the optical axis characteristics, resulting in poor versatility.

The configurations described in Japanese Patent Laid-Open No. 5-136952 and Japanese Patent Laid-Open No. 5-273483 are mounted only from above. Similarly, the cost and the accuracy of the optical axis characteristic are disadvantageous and the versatility is poor. There is a problem.

(6) The semiconductor laser used in the light source device is a component that is easily deteriorated or destroyed by electrical noise such as static electricity. Therefore, it is ideal to assemble and adjust the light source fully automatically in order to eliminate the influence of static electricity from the human body. When the assembly and adjustment of the light source device is automated, improvement in quality and yield can be expected along with cost merit due to reduction of labor cost.

In the case of automation, the work set reference plane of the automatic machine is not limited to the light source device but is set horizontally.
This structure is advantageous for loading and unloading workpieces. When the light source device described in JP-A-5-88061 is automated, the light source device is set to face downward (laser light emission is face down) because the reference plane of the light source device is the plane 5a perpendicular to the optical axis. This is an automatic machine configuration that is easy to automate. In this case, the adhesive injection after the automatic adjustment of the focus position of the collimator lens 8 is performed from the downward direction or the lateral direction, and it is difficult to inject the adhesive considering the dripping of the adhesive. In addition, the subsequent process of inserting the aperture is also from the downward direction, and it is necessary to consider a complicated automatic machine or another process.

The present invention has been made in view of the above-mentioned problems, has a small number of constituent parts, does not have a risk of positional displacement during manufacture, and facilitates automation of assembly adjustment.
It is an object of the present invention to provide an inexpensive, highly accurate, and highly versatile light source device that can use an ultraviolet curable adhesive.

[0023]

In order to achieve the above object, a first invention is to provide a first holding part for holding a semiconductor laser, a second holding part for holding a lens, and a laser beam of the semiconductor laser. A light source device having an aperture for adjusting, wherein the first holding unit has a surface perpendicular to the optical axis of the laser light of the semiconductor laser, and the second holding unit has a surface perpendicular to the optical axis. A light source device having parallel surfaces. A second aspect of the invention is a light source device according to the first aspect of the invention, in which the first and second holding bodies are integrated. A third invention is a light source device having a first holding part for holding a semiconductor laser, a second holding part for holding a lens, and an aperture for adjusting a laser beam of the semiconductor laser. A third holding part is provided perpendicular to the optical axis, the second holding part is provided in front of the first holding part to support the lens from below, and the second holding part is provided to support the aperture from below. The light source device is characterized in that a holding portion is provided.

Further, in a fourth aspect based on the third aspect, the reference surface for positioning the upper unit mounting position on the vertical surface of the first holding portion and the lower surface for positioning the upper unit mounting position on the bottom surface of the second holding portion. Is a light source device. A fifth invention is a light source device according to any one of the first to fourth inventions, characterized in that the supporting surface for supporting the lens is a concave surface. The sixth invention is the same as the third invention.
The light source device is characterized in that the third holding portion supports the aperture by an elastic function provided in the aperture.
A seventh invention is the light source device according to the third invention, wherein the first to third holding portions are integrated.
An eighth invention is the light source device according to any one of the first to fourth inventions, characterized in that the first and second holding portions are L-shaped.

Further, the first holding portion is an infrared ray (about 780
(nm) or less and a material that does not transmit a wavelength of less than or equal to (nm), and the lens is preferably a material that can transmit an ultraviolet ray. Further, it is preferable that the lens is set parallel to the optical axis and fixed to the third holding portion with an ultraviolet curing adhesive.

[0026]

The light source device of the present invention configured as described above is
The holding portion for holding the semiconductor laser has a surface vertical to the optical axis, and the second holding portion for holding the lens has a surface parallel to the optical axis. Also, the light source device can be securely attached to the main body or the upper unit without impairing the collimating characteristics of the light source device.
Further, since the holding portion can be integrally formed, the number of parts can be reduced. Further, since the recollimators and the aperture can be incorporated from the vertical direction, automation becomes easy.

Further, since the adhesive filling the gap between the positioned lens and the surface of the holding member by using the ultraviolet transmissive lens is irradiated with the ultraviolet rays passing through the lens, the entire adhesive is It is hardened uniformly. Furthermore, since the member that holds the semiconductor laser is a material that does not transmit a wavelength of infrared rays (about 780 nm) or less, the infrared laser does not leak except in the optical axis direction. Safety is assured when mounting or when using the light source device.

[0028]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view showing a light source device according to the present invention, and FIG. 2 is a front view. The same parts as those in the conventional example are designated by the same reference numerals. In the embodiment of FIG. 1, the semiconductor laser 3 for irradiating the laser light, the collimator lens 8 for converting the laser light into a substantially parallel light flux, and the semiconductor laser 3
The base 15 is provided as a holding member. Base 15
Is a material that does not transmit light having a wavelength of infrared rays (about 780 mm) or less.

The semiconductor laser 3 is fixed by being press-fitted into a stepped hole 15a formed in the center of the base 15. The printed circuit board 9 is a guide pin 1 formed at the tip of two spacers 15b integrally provided on the base 15.
Correspondingly, 5c is fitted and fixed in the positioning hole 9a of the printed board 9 formed slightly smaller than the outer shape of the guide pin 15c. Then, with the base 15 fixed to the printed circuit board 9, the respective lead wires 12 of the semiconductor laser 3 are placed substantially at the center of the printed circuit board 9.
The holes 9b corresponding to the number of holes are inserted into the holes 9b, and they are joined to the conductive pattern portions on the printed board 9 by soldering.

The aperture forming member 16 forming the aperture 16a has a cut and bent portion 16b, is inserted into a groove 15d formed in the base 15, and is fixed by the spring force of the cut and bent portion 16b. The base 15 is provided with a concave surface 15e, and the collimator lens 8 having an outer periphery substantially parallel to the concave surface 15e is held by a chuck (not shown) whose position can be adjusted in three axes (x, y, z). A gap of about 0.5 mm is formed between the groove 8 and the concave surface 15e. The adhesive is injected into this gap.

The collimator lens 8 is made of a material capable of transmitting ultraviolet rays, and a plastic molded product or a glass pressed product is considered, but a glass pressed product having excellent optical characteristics is preferable. The collimator lens 8 is an aperture forming member 16
After fixing, the adhesive 21 is filled in the gap while finely adjusting in the x, y, and z directions while inspecting the optical characteristics such as the collimating characteristics of the laser light emitted through the aperture 16a, and the ultraviolet irradiator. UV light from 22
1 is solidified in a short time. Since the collimator lens 8 is transparent to ultraviolet light, the adhesive 21 is uniformly solidified and the collimator lens 8 is fixed. Therefore, the collimator lens 8
Is fixed to the concave surface 15e of the holding portion with the adhesive 21 while maintaining the collimator characteristics.

Next, a method for mounting the light source device according to the present invention on a main body of a digital copying machine, a laser printer, or the like, or a host unit in which the light source device is incorporated will be described. The base 15 is L-shaped, and the first reference surface 15f of the base 15 is a plane parallel to the outgoing optical axis.
The reference surface 15g is a plane perpendicular to the outgoing optical axis. When the light source device is attached to the main body or the upper unit from above, positioning is performed in the rotation direction (x, z directions) by the two positioning holes 15h, 15h, and then by the two screw holes 15i, 15i. The light source device is fixed by screwing it from above and bringing the first reference surface 15f into close contact with the reference surface of the main body or the upper unit. When the light source device is attached to the main body or the upper unit from the side surface, the two positioning holes 15j and 15j are used for positioning in the rotational direction (x and y directions), and the two screw holes 15k and 15k are used to screw from the side surface. Then, the second reference surface 15g is brought into close contact with the reference surface of the main body or the upper unit to fix the light source device.

Next, when the light source device according to the present invention is automatically assembled and adjusted by an automatic machine, first, the second reference surface 15g of the base 15 is installed horizontally, and the lead wire 12 of the semiconductor laser 3 is installed from above. It is joined to the conductive pattern portion of the printed board 9 by soldering. The optical characteristics are adjusted with the first reference surface 15f of the base 15 installed horizontally.
In this case, the aperture forming member 16 is inserted, the adhesive 21 is applied, the collimator lens 8 is installed and the position is adjusted, and the ultraviolet irradiation is performed by the ultraviolet irradiation device 22 from above. Is easy.

It is obvious that the holding member on which the first and second reference surfaces are formed may be a separate body or an integral body. Further, the portions to which the aperture forming member 16 and the collimator lens 8 are fixed may be the same member or different members, and these members and the holder of the base 15 on which the parallel reference plane is formed. It may be an integral body or a separate body. Of course, even if the portion where the collimator lens 8 is installed is a surface different from the horizontal reference plane, the collimator lens 8 is fixed with the adhesive 21 after the optical characteristics such as the collimator characteristics of the collimator lens 8 are confirmed. , Does not affect the collimation characteristics.

[0035]

Since the present invention is constructed as described above, it has the following effects. (1) The collimator lens has a vertical reference plane and a parallel reference plane with respect to the optical axis of the semiconductor laser, and the collimator lens is fixed according to the optical axis. There are advantages. (2) Since the holder can be integrally formed, the number of constituent parts of the light source device can be reduced, and an inexpensive light source device can be provided. Further, since the number of constituent parts is reduced and the tightening portion of the screw is eliminated, the deviation of the parts when tightening the screw is eliminated, and a highly accurate light source device can be provided.

(3) Since the ultraviolet-curable adhesive is solidified by the ultraviolet rays that have passed through the collimator lens, the adhesive can be uniformly irradiated and completely cured, and uneven curing and uncured portions can be prevented. . In addition, the semiconductor laser light has a structure that does not leak to the outside except in the optical axis direction, and thus it is possible to prevent the adhesive from changing with time.

(4) Since the focus position of the collimator lens can be adjusted after assembling the aperture, there is no variation in the optical characteristics after assembling the aperture, and a light source device having stable optical characteristics can be provided. (5) When the light source device is attached to the main body of a digital copying machine or a laser printer, or a host unit in which the light source device is incorporated, the first reference plane perpendicular to the emission optical axis of the laser light and the second reference plane parallel to the emission optical axis. Since it has a surface, it can be attached from above and laterally, and a highly versatile light source device can be provided. (6) By having the first reference surface that is perpendicular to the emission optical axis of the laser light, insertion of the aperture forming member, application of adhesive,
Since the position adjustment of the collimator lens and the irradiation of ultraviolet rays can all be performed from above, there is an advantage that it is possible to provide a light source device whose assembly and adjustment can be easily automated.

[Brief description of drawings]

FIG. 1 is a sectional view taken along the line AA of FIG. 2 showing a first embodiment of a light source device according to the present invention.

2 is a plan view of the embodiment of FIG. 1. FIG.

FIG. 3 is a cross-sectional view of a conventional light source device.

FIG. 4 is a perspective view of a conventional light source device.

[Explanation of symbols]

 3 semiconductor laser 8 collimator lens 9 printed board 11 guide pin 15 base 15a stepped hole 15b spacer 15c guide pin 15d groove 15e concave surface 15f first reference surface 15g second reference surface 15h, 15j positioning hole 15i, 15k screw hole 16 aperture formation Member 16a Aperture 16b Cutting / bending part 21 Adhesive

Claims (8)

[Claims] 1. A first holding unit for holding a semiconductor laser,
In a light source device having a second holding unit for holding a lens and an aperture for adjusting a laser beam of the semiconductor laser, the first holding unit includes a reference plane perpendicular to the optical axis of the laser beam of the semiconductor laser. In addition, the light source device is characterized in that the second holding portion is provided with a reference surface parallel to the optical axis. 2. The light source device according to claim 1, wherein the first and second holding portions are integrated. 3. A first holding part for holding a semiconductor laser,
In a light source device having a second holding part for holding a lens and an aperture for adjusting a laser beam of the semiconductor laser, the first holding part is provided perpendicular to an optical axis, and is provided in front of the first holding part. A light source device, comprising: the second holding portion that supports the lens from below; and the third holding portion that supports the aperture from below in the second holding portion. 4. The vertical surface of the first holding portion is provided with a first reference surface for positioning the upper unit mounting position, and the bottom surface of the second holding portion is provided with a second reference surface for positioning the upper unit mounting position. The light source device according to claim 3, wherein the light source device is a light source device. 5. The light source device according to claim 1, wherein a supporting surface that supports the lens is a concave surface. 6. The light source device according to claim 3, wherein the aperture is supported by the third holding portion by an elastic function provided in the aperture. 7. The light source device according to claim 3, wherein the first to third holding portions are integrated. 8. The light source device according to claim 1, wherein the first and second holding portions are L-shaped.