JP4083825B2 - Light source device - Google Patents

Description

[0001]
BACKGROUND 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]
[Prior art]
In a light source device using a semiconductor laser, the directivity (optical axis property) of laser light emitted from the light source device and the parallelism (collimating property) of a light beam are required as optical characteristics. For this reason, the light source device normally adjusts the relative position of the light emitting point of the semiconductor laser and the collimator lens in the triaxial (x, y, z) directions, and the positional accuracy is required to be less than a micron. ing. Therefore, a light source device having a semiconductor laser and a collimator lens must have a structure capable of adjusting the position in the three axial directions and fixing at the adjusted position.
[0003]
When the collimator lens is fixed with an adhesive, shrinkage of the adhesive occurs at the time of curing. Therefore, it is ideal to minimize the adverse effect on the optical characteristics due to the shrinkage. In particular, since the required accuracy in the z direction (optical axis direction) is high in the light source device, it is desirable to configure the contraction direction not to occur in the z axis direction. For this reason, the adhesive layer is usually set in a direction substantially parallel to the optical axis (direction parallel to the z-axis), and other axis directions (x and y directions) are also easily adjusted. It is desirable that the contraction direction be one direction of the x-axis or y-axis direction as much as possible.
[0004]
FIG. 5 shows an example of a conventional light source device (Japanese Patent Laid-Open No. 5-88061).
This light source device was previously filed by the present applicant, and as shown in the figure, a semiconductor laser 103 for irradiating laser light is press-fitted and fixed in a stepped hole 102 provided in a base 101 as a holding member. ing. A flange 105 attached to the base 101 by two screws 104 and 104 is formed with a fitting hole 106 at a position facing the stepped hole 102, and a fitting hole 106 is fitted at the left end of the fitting hole 106. An inlet portion 106 a having a diameter of about 0.1 mm larger than the joint hole 106 is formed.
[0005]
A cylindrical lens holder 107 having a clearance of about 0.01 to 0.03 mm from the fitting hole 106 is fitted into the fitting hole 106, and laser light is parallelized in the lens holder 107. A collimator lens 108 for conversion to a light beam is held.
[0006]
On the other hand, a guide pin 111 protruding from the end surface of the base 101 is inserted into the positioning hole 110 formed in the printed circuit board 109, and the tip portion of the guide pin 111 is melted by heat as indicated by a virtual line. By crushing, the base 101 and the printed circuit board 109 are fixed. The lead wire 112 of the semiconductor laser 103 is passed through a lead wire insertion hole formed in the printed circuit board 109 and soldered to a conductive pattern for wiring on the back surface side of the printed circuit board.
[0007]
The flange 105 is fixed to the base 101 by a screw 104 after adjusting the position in the x and y directions so that the light emitting point of the semiconductor laser 103 coincides with the optical axis of the collimator lens 108.
[0008]
The flange 105 attached to the base 101 is formed with a notch 113 connected to the inlet 106a. The lens holder 107 is moved in the z direction so that the light source position of the semiconductor laser 103 coincides with the focal position of the collimator lens 108. After the position adjustment, the lens holder 107 is fixed to the flange 105 by injecting an adhesive from the notch 113 and penetrating the adhesive.
[0009]
The aperture forming member 114 is a shielding cap for taking out and shaping a parallel light beam in the vicinity of the center of the light beam that has passed through the collimator lens 108, and is fitted to the aperture 114 a made up of a light beam selection hole and the flange 105. The aperture forming member 114 is fixed to the flange 105 by fitting the projection 114b into the notch 113 of the flange 105.
[0010]
When the light source device is attached to a digital copying machine or a laser printer main body, a plane 105a perpendicular to the optical axis of the flange 105 serves as a reference plane, and optical characteristics are adjusted based on this plane 105a.
[0011]
[Problems to be solved by the invention]
However, the above-described conventional light source device has the following problems.
(1) Since the x- and y-direction adjustment unit (optical axis characteristic adjustment unit) and the z-direction adjustment unit (collimation characteristics, that is, the focal direction adjustment unit) have separate structures, the components of the light source device The score is high and the product is expensive.
[0012]
(2) Since the screw 104 is tightened after adjusting in the x and y directions and the flange 105 is fixed to the base 101, the screw seat on the end surface of the base 101 and the flange 105 are engaged when the screw 104 is tightened. As a result, positional deviation in the x and y directions may occur, and the accuracy of laser directionality (optical axis characteristics) may be reduced.
[0013]
(3) The laser light of the semiconductor laser 103 used in the light source device has a certain spread, and not all of the laser light is incident on the collimator lens 108. The semiconductor laser has a legal standard from the viewpoint of safety to the human body, and it is desirable that the laser beam does not leak outside the optical axis direction. This is the same not only during use but also at the time of adjustment in the manufacturing process, and the flange 105 and the base 101 need to be made of a material that does not leak laser light to the outside.
[0014]
On the other hand, as the adhesive used for fixing the lens holder 107, an ultraviolet curable adhesive that can be arbitrarily cured in a short time is advantageous for shortening the production tact and has excellent reliability. However, when the base 101 or the flange 105 is made of a material that does not allow ultraviolet light to pass therethrough as in the light source device of the prior application, the filled adhesive can be used even if ultraviolet rays are irradiated through a gap filled with an ultraviolet curable adhesive. The whole cannot be irradiated evenly, resulting in uneven curing and uncured portions. For this reason, distortion due to curing shrinkage acts unevenly, resulting in problems such as displacement of the lens holder 107 and cracking of the constituent members.
[0015]
A material that does not transmit laser light such as infrared light and red light emitted from the laser light source 103 does not transmit ultraviolet light having a shorter wavelength. For this reason, if only ultraviolet rays are transmitted, a special filter must be added or a special coating must be applied to the flange 105 itself, resulting in a problem that the cost is significantly increased. Therefore, an ultraviolet curable adhesive cannot be used as an adhesive for fixing the collimator lens 108.
[0016]
(4) Since the adhesive layer exists on the entire circumferential surface of the lens holder 107, that is, in all directions of x and y, the curing shrinkage direction of the adhesive in the x and y directions is not determined, and the positional accuracy in the x and y directions varies. Will occur. To ensure positional accuracy after bonding, it is also necessary to offset the initial position in anticipation of a certain amount of contraction, but if the contraction direction of the adhesive layer is not constant, it is difficult to provide an offset, and the laser direction Accuracy (optical axis characteristics) may be reduced.
[0017]
The present invention has been made in order to solve the above-described problems. The number of components is small, and there is no risk of displacement during assembly, and a collimator lens is bonded using a photo-curing adhesive. An object of the present invention is to provide an inexpensive and highly accurate light source device.
[0018]
[Means for Solving the Problems]
In order to solve the above problems, the present invention employs the following means.
That is, a first aspect of the present invention, a base having a fitting hole penetrating a substrate and a base said front and back to front and the opposite side attached substrate side and back to the substrate, the holding the back side of the base and the semiconductor laser is fitted in the fitting hole, the semiconductor laser of the optical axis coaxial with the exit position of the semiconductor laser than the opening of the a front side of the base fitting hole a collimator lens that is, an aperture forming member for shaping a laser beam emitted from the collimator lens, and the base of the front side in adjacent to the opening of the fitting hole lens supporting portion formed integrally on the base In the light source device, the lens support portion has an arc surface on the optical axis side in which a shape of a cross section in a plane perpendicular to the optical axis of the semiconductor laser is an arc,
The diameter of the circle including the arc of the arc surface is slightly larger than the outer circumference circle in the cross section of the collimator lens, and the center of the circle including the arc is on the optical axis of the semiconductor laser, and arc of the arc surface is less semicircle, the adhesive of the photocurable type is interposed between the outer periphery of the circular arc surface and the collimator lens of the lens support portion, said collimator lens to said lens supporting portion on There is characterized in that it is directly bonded and fixed.
[0019]
In such a configuration, since the number of components of the light source device can be reduced, the structure is simplified and the position accuracy can be increased. Further, in the production thereof, curing can be performed by directly irradiating a curing light beam such as ultraviolet rays from above the collimator lens toward the adhesive layer. Further, since the lens support portion is formed concentrically with the optical axis of the semiconductor laser, the adhesive layer formed between the collimator lens and the lens support portion has a uniform thickness. For this reason, since the entire surface of the adhesive layer is uniformly solidified, there is no unevenness in curing, and displacement of the collimator lens is prevented.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 to 4 show an example of the light source device of the present invention. 1 is a longitudinal sectional view of a light source device, FIG. 2 is an exploded perspective view thereof, FIG. 3 is a schematic front view of a collimator lens and a lens support portion, and FIG. 4 is a schematic longitudinal sectional view of a collimator lens and a lens support portion. .
[0025]
1 and 2, reference numeral 1 denotes a printed circuit board, 2 denotes a semiconductor laser, 3 denotes a base serving as a holding member for the semiconductor laser 2, 4 denotes a collimator lens, and 5 denotes an aperture forming member. The base 3 is made of a material that does not transmit infrared laser light (for example, 780 nm) emitted from the semiconductor laser 2 and light having a shorter wavelength. The semiconductor laser 2 is press-fitted and fixed from the back side of the base into a stepped fitting hole 3a formed at the center of the base 3 and penetrating the front and back.
[0026]
Two spacers 3b and 3b are formed on the back side of the base 3, and screw holes 3c and 3c for fixing the printed circuit board are formed in the spacers 3b and 3b. Two through holes 1a and 1a are formed in the printed circuit board 1 at positions opposite to the screw holes 3c. By screwing the screws 6 into the screw holes 3c through the through holes 1a, the base 3 The printed circuit board 1 is fixed. The screw hole 3c may be a round hole without a thread groove, and the screw 6 may be a tapping screw.
[0027]
The three lead wires 2a of the semiconductor laser 2 are respectively inserted into three lead wire insertion holes 1b formed in the printed circuit board 109, and soldered to a conductive pattern for wiring on the back surface side of the printed circuit board.
[0028]
In order to directly bond and fix the collimator lens 4 to the base 3, the base 3 is positioned on the front surface side of the fitting hole 3 a and has a slightly larger diameter than the outer circumferential circle of the collimator lens 4 (for example, 0. A lens support portion 3d having an arc-shaped cross section is integrally formed concentrically with the optical axis of the semiconductor laser 2.
[0029]
The dimension of the lens support portion 3d in the optical axis direction (z direction) is such that even if the adhesive is excessively filled, the collimator lens 4 is not attached to other portions in the optical axis direction (z direction). Longer than the lens thickness. Further, the shape when viewed from the front side is an arc of a cross section of a semicircle or less. Note that the shape when viewed from the front is preferably a symmetrical circular arc that is opened at about 60 °, as shown in FIG. 3, for ease of position adjustment and bonding work.
[0030]
The collimator lens 4 is made of a material that can transmit ultraviolet rays. A plastic lens or a glass lens can be considered as a lens of such a material, but a glass lens having excellent optical characteristics is more preferable. When the collimator lens 4 is assembled, as shown in FIG. 3, the collimator lens 4 is held by chucks 7 and 7 whose positions can be adjusted in the three-axis (x, y, z) directions, and the light of the semiconductor laser 2 is placed on the lens support portion 3d. Arranged concentrically with the shaft.
[0031]
Then, after filling the gap formed between the adhesive surface 3e of the lens support 3d and the outer peripheral surface of the collimator lens 4 with an ultraviolet curable adhesive 8, the optical characteristics are inspected by an inspection device (not shown). After finely adjusting the position of the collimator lens 4 and determining the position where the desired optical characteristics can be obtained, the chucks 7 and 7 are fixed at the position, and the adhesive is applied from above the collimator lens 4 as shown in FIGS. 8 is irradiated with ultraviolet rays L by an ultraviolet irradiator 9.
[0032]
The ultraviolet light L irradiated from the ultraviolet irradiator 9 is transmitted through the collimator lens 4 and irradiated onto the adhesive 8 portion, and the entire adhesive 8 is uniformly cured. Therefore, a uniform and symmetrical adhesive layer having a gap dimension (about 0.3 mm) is formed between the adhesive surface 3e of the lens support portion 3d and the collimator lens 4, and the collimator lens 4 is formed of the adhesive layer. Is fixed on the lens support portion 3d while maintaining predetermined optical characteristics.
[0033]
In particular, as shown in FIG. 3, when the lens support portion 3d has a left-right symmetrical circular arc shape opened at about 60 °, the collimator lens 4 can be easily and reliably supported by the chucks 7 and 7. The ultraviolet light L emitted from the ultraviolet irradiator 9 can be evenly applied to the entire surface of the adhesive surface 3e through the collimator lens 4, and the adhesive can be cured uniformly and completely. For this reason, a completely solidified and uniform adhesive layer can be obtained, and the occurrence of unevenness in curing and misalignment of the collimator lens 4 based on the uncured portion can be eliminated.
[0034]
Further, distortion due to curing shrinkage of the adhesive occurs in the x direction (left and right direction) symmetrically and is canceled out, and is limited to only one direction in the y direction (up and down direction). Therefore, it is possible to slightly offset the position in the y direction of the collimator lens 4 before curing in anticipation of the contraction amount, and the accuracy of the optical characteristics after the collimator lens 4 is fixed is improved.
[0035]
The aperture forming member 5 is formed with an aperture 5a, two protrusions 5b and 5b for fixing to the base 3, and two arc-shaped grooves 3g and 3g for alignment. Then, after the adhesive fixing of the collimator lens 4 is completed as described above, the two arc-shaped protrusions 5c, 5c of the aperture forming member 5 are arranged around the circular step portion 3h formed at the base portion of the lens support portion 3d. The two arc-shaped grooves 3g, 3g on the surface are aligned and face each other, and in this state, the aperture forming member 5 is pushed toward the base 3 side. Accordingly, the two protrusions 5b and 5b of the aperture forming member 5 are fitted into the two notches 3f and 3f on the circumferential surface of the circular step portion 3h, and the aperture forming member 5 is fixed to the circular step portion 3h.
[0036]
Two elongated holes 3i, 3i formed at both left and right ends of the base 3 are mounting holes for mounting the light source device to a digital copying machine or a laser printer body. At the time of this attachment, the vertical plane 3j on the surface side of the base 3 and the outer peripheral surface of the circular step portion 3h serve as a reference plane for alignment.
[0037]
In the example described above, an ultraviolet curable adhesive is used, but not only the ultraviolet curable adhesive, but any photocurable adhesive can be used.
[0038]
【The invention's effect】
As has been the description, when according to the invention of claim 1 wherein, fitted to the substrate, and the opposite side as the back of the attached substrate side to said substrate a base to the table through the front and back base, a semiconductor laser from the back side of the base is fitted into the fitting hole, the semiconductor laser in the injection position of the the opening of the a front side of the base fitting hole semiconductor laser having a hole of the collimator lens held in the optical axis coaxial with the aperture forming member for shaping the laser beam emitted from the collimator lens, adjacent to the opening of the fitting hole on the front side of the base integrally with the base In the light source device including the formed lens support portion , the lens support portion has an arc surface on the optical axis side in which a cross-sectional shape of the surface perpendicular to the optical axis of the semiconductor laser is an arc. Arc The diameter of the circle including the arc is slightly larger than the outer circumference circle in the cross section of the collimator lens, the center of the circle including the arc is on the optical axis of the semiconductor laser, and the arc surface the arc is less semicircle, wherein the arc surface of the lens supporting portions and the photocurable adhesive is interposed between the outer periphery of said collimator lens, said collimator lens is directly on the lens supporting portions on the adhesive Since it is fixed, the excellent effects described in (1) to ( 5 ) below are exhibited.
[0039]
(1) Since the collimator lens is configured to be directly fixed to the lens support unit formed integrally with the base, the number of parts of the light source device can be reduced, and the light source device can be provided at low cost.
[0040]
(2) Also, the collimator lens is configured to be directly fixed to the lens support part that is integrally formed on the base, so that the tightening part such as screws is eliminated, and there is no displacement of the parts when tightening, and a high-precision light source device Can be provided.
[0041]
(3) The collimator lens can be bonded and fixed using a photo-curing adhesive, despite the structure in which the semiconductor laser beam does not leak outside the optical axis direction.
[0042]
(4) Since the collimator lens is adhesively fixed on the lens support portion having a circular arc cross section using a photo-curing adhesive, a curing light beam is directed from above the collimator lens toward the adhesive layer in the production. Direct irradiation can cure the adhesive. Further, since the lens support part is formed concentrically with the optical axis of the semiconductor laser, the adhesive layer formed between the lens support part and the collimator lens can be made to have a uniform thickness. For this reason, since the entire surface of the adhesive layer is uniformly solidified, there is no unevenness in curing, and a high-quality light source device free from misalignment of the collimator lens due to curing shrinkage can be provided.
[0044]
(5) The adhesive layer is only the lower half of the outer periphery of the collimator lens, and the direction of curing shrinkage appears, so it is possible to offset the initial position of the collimator lens with a certain amount of shrinkage, and the positional accuracy after fixing Can be improved. Furthermore, irradiation of the curing light beam from above the collimator lens is facilitated, and curing unevenness is further eliminated. For this reason, position accuracy can be improved more.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing an example of a light source device of the present invention.
2 is an exploded perspective view of the light source device of FIG. 1. FIG.
FIG. 3 is a schematic front view of a collimator lens and a lens support portion.
FIG. 4 is a schematic cross-sectional view of a collimator lens and a lens support portion.
FIG. 5 is a longitudinal sectional view of a conventional light source device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Printed circuit board 1b Lead wire penetration hole 2 Semiconductor laser 2a Lead wire 3 Base 3a Fitting hole 3b Spacer 3c Screw hole 3d Lens support part 3e Adhesive surface 3f Notch part 3g Circular groove 3h Circular step part 3i Long hole 3j Vertical plane 4 Collimator lens 5 Aperture forming member 5a Aperture 5b Protrusion 5c Arc-shaped protrusion 6 Screw 7 Chuck 8 UV curable adhesive L UV

Claims (1)

A substrate,
A base having a fitting hole penetrating the front and back of the substrate side mounted on the substrate and the opposite side as the back a base to the table,
A semiconductor laser which is fitted into the fitting hole from the back side of the base,
A collimator lens held in the optical axis coaxial with the semiconductor laser in the injection position of the semiconductor laser than the opening of the fitting hole a front side of said base,
An aperture forming member for shaping a laser beam emitted from the collimator lens,
In a light source device comprising a lens support portion formed integrally with the base adjacent to the opening of the fitting hole on the front side of the base ,
The lens support portion has an arc surface on the optical axis side in which the shape of a cross section in a plane perpendicular to the optical axis of the semiconductor laser is an arc,
The diameter of the circle including the arc of the arc surface is slightly larger than the outer circumference circle in the cross section of the collimator lens, and the center of the circle including the arc is on the optical axis of the semiconductor laser, and The arc of the arc surface is less than a semicircle,
The adhesive of the photocurable type is interposed between the outer periphery of the circular arc surface and the collimator lens of the lens support portion, characterized in that said collimator lens is adhered and fixed directly to the lens support portion on Light source device.

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