JP2004095994A - Light source equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide light source equipment which enhances reliability for an optical performance by firmly fixing the collimator lenses. <P>SOLUTION: Cylindrical portions 22a, 22b are each provided with a plurality of first notches 23 which pass through the inner and outer peripheries thereof. Protrusions 25, which are formed between the first notches 23, for supporting the collimator lenses 3a, 3b are arranged at positions for providing even intervals therebetween with respect to the outer periphery of each of the collimator lenses 3a, 3b. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a light source device suitable for an image forming apparatus such as a laser beam printer or a digital copying machine having an electrophotographic process. More particularly, the present invention relates to a multi-beam laser light source device which is used by simultaneously scanning a plurality of laser beams on a photosensitive drum or the like on a surface to be scanned.
[0002]
[Prior art]
In recent years, in order to obtain a high-speed or high-definition image, a multi-beam scanning optical device that scans a plurality of light beams on a photoconductor has been put to practical use.
[0003]
On the other hand, there is also a multi-beam scanning optical device which simultaneously scans a plurality of photoconductors used for in-line color with a plurality of light beams.
[0004]
These are multi-beam scanning optical devices that arrange the respective light beams emitted from a plurality of semiconductor lasers, which are light sources, close to each other, and combine or split the light beams depending on the application to emit the plurality of light beams.
[0005]
For example, there is a multi-beam scanning optical device S shown in FIG. In the multi-beam scanning optical device S of FIG. 6, the plurality of light beams L emitted from the light source device R are substantially coaxial with the optical axis of the imaging lens by the beam combining means including the prism A disposed in the housing. The images are synthesized, deflected and scanned by a scanner motor provided with a polygon mirror D via a cylindrical lens B, and imaged on a photoreceptor I via imaging lenses F and G and a reflection mirror H.
[0006]
Conventionally, as an example of the light source device R used in the above-described multi-beam scanning optical device S, for example, a plurality of semiconductor lasers as a light source described in Patent Document 1 and laser light emitted from each of the semiconductor lasers are substantially described. A multi-beam light source device including a plurality of collimator lenses that collimate light has been proposed.
[0007]
[Patent Document 1]
JP-A-11-153737
As shown in FIG. 7, in the multi-beam light source device, the lens supporting portion 123 of the holder member 102 holding each of the semiconductor laser 101 and the collimator lens 103 has a specific arc region with respect to the outer periphery of the collimator lens 103. This is a cantilever support configuration in which the collimator lens 103 is partially adhered and fixed.
[0009]
[Problems to be solved by the invention]
In the above prior art, the collimator lens is adjusted with high precision with respect to the holder member holding the semiconductor laser, and fixed and held without destroying the relative positional relationship between the semiconductor laser and the collimator lens. Accuracy is required.
[0010]
In addition, this relationship must be maintained under any environment in each state where the light source device and the scanning optical device are assembled.
[0011]
However, a multi-beam light source device that has a plurality of pairs of a semiconductor laser and a collimator lens and emits a plurality of laser beams in which these are integrated has the following problems.
[0012]
In an optical system that simultaneously scans a beam using a beam combining unit after a plurality of light beams are emitted, a beam pitch interval in the sub-scanning direction is required with very high accuracy.
[0013]
Therefore, if the beam optical axis is deviated from the optical axis of the imaging lens, or if the beam emission angle is different, the beam pitch interval changes and image deterioration is a concern.
[0014]
The same applies to an optical system that scans beams on a plurality of photoconductors using a beam separation unit or the like after a plurality of light beams are emitted. For example, when used in in-line color or the like, the relative irradiation position of the beam changes, causing color shift.
[0015]
These factors include, for example, a method of bonding a collimator lens described later in the related art.
[0016]
As a method for bonding the collimator lens 103 in FIG. 7, first, an adhesive is applied to an arc portion of the lens support portion 123 of the holder member 102.
[0017]
Later, the collimator lens 103 held by a lens clamp tool inserted from an open space other than the lens support portion determines the focal length (optical axis direction) and the irradiation position (the direction orthogonal to the optical axis) of the collimator lens. Adjust to position.
[0018]
After the adjustment, the holder is fixed to the collimator lens 103 by irradiating ultraviolet rays or the like to the bonding site to cure the adhesive.
[0019]
Here, the bonding area of the collimator lens 103 is bonded to the outer peripheral surface of the collimator lens 103 only at a part of the arc portion. At this time, the irradiation position of the collimator lens 103 is changed only in one direction where the adhesive layer exists due to the curing shrinkage of the adhesive, so that the collimator lens 103 is shifted with respect to the optical axis of the imaging lens.
[0020]
Further, since the arc-shaped support portion 123 holding the collimator lens 103 is cantilevered depending on the subsequent atmospheric environment, the lens support portion 123 is easily deformed due to thermal expansion, and the rigidity is inferior.
[0021]
Further, depending on changes in temperature or humidity of the environment, etc., the collimator lens 103 is tilted to both sides in the optical axis direction with the adhesion portion as a fulcrum due to stress generated from expansion of the adhesive due to heat or moisture absorption, thereby causing the inclination of the lens optical axis. Deteriorates, the irradiation position fluctuates, and the focal length shifts. In other words, there has been a concern about deterioration of optical performance such as a change in the sub-scanning beam pitch interval and the beam emission angle (parallelism).
[0022]
In addition, since the fixing portion of the collimator lens 103 is limited, and the design is limited by optical design and processing, the thickness of the lens is generally reduced, so that the bonding area is narrowed and the bonding strength of the collimator lens 103 is reduced. There is a concern that the lens may be easily peeled off, a load may be applied due to environmental resistance, vibration, impact, or the like, and the lens may be displaced.
[0023]
Furthermore, since the collimator lens 103 is open except for the fixed portion, it is necessary to pay sufficient attention to external contact, impact, and the like during the operation in the assembly process and when assembling the unit.
[0024]
SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a light source device in which a robust collimator lens is fixed to enhance the reliability of optical performance.
[0025]
[Means for Solving the Problems]
In order to achieve the above object, in the present invention,
A light source comprising: a plurality of semiconductor lasers serving as a light source; a collimator lens that converts each laser beam emitted from the semiconductor laser into substantially parallel light; and a holder member that holds a plurality of sets of the semiconductor laser and the collimator lens. In the device,
The holder member includes a cylindrical portion that holds each of the collimator lenses,
The cylindrical portion has a plurality of first notches penetrating the inner and outer circumferences,
The projections formed between the first cutouts and holding the collimator lens are arranged at equal circumferential intervals with respect to the outer periphery of each of the collimator lenses.
[0026]
In the above configuration, the plurality of protrusions holding the collimator lens form an adhesive layer on the circumference of each collimator lens so as to be evenly divided, whereby the collimator cures or shrinks due to the adhesive, or the thermal expansion of the holder member or the like. By dispersing the behavior of the lens in the circumferential direction with a good balance, the direction of displacement of the collimator lens can be stabilized, and the amount of fluctuation can be reduced. Therefore, the fixing accuracy is improved, and it is possible to suppress the relative positional deviation of each optical axis inclination.
[0027]
Further, the plurality of protrusions for bonding and fixing the collimator lens can increase the rigidity of the holding portion for holding the collimator lens, and increase the bonding area, thereby obtaining the bonding strength. The direction can be stabilized, and the amount of fluctuation can be reduced. Therefore, similarly to the above, the fixing accuracy is improved, and it is possible to suppress the relative positional deviation of each optical axis inclination.
[0028]
It is preferable that a second cutout portion used for filling the adhesive is provided on the protrusion.
[0029]
In the above configuration, the adhesive filling the groove of the second cutout is filled while sneaking into the gap between the engaging portion of the collimator lens and the holder member. Enables accurate bonding and fixing.
[0030]
It is preferable that at least one of the plurality of protrusions supporting the collimator lens is shared.
[0031]
In the above configuration, since each collimator lens can be arranged closer to each other, the distance between optical axes can be reduced, and the unit can be made compact. In addition, by reducing the distance between the optical axes, it is generally possible to suppress the sensitivity of a beam combining optical system to a low level, so that the beam irradiation position accuracy can be relaxed and restrictions due to mechanical design and optical design are reduced. This is advantageous because it can be alleviated.
[0032]
Further, the degree of freedom of the movable region of the clamp tool for adjusting each collimator lens is increased, and the work can be performed efficiently, so that the assemblability can be improved.
[0033]
It is preferable that the protruding portion is disposed on a side facing the first notch.
[0034]
In the above configuration, the light irradiation direction when the photocurable adhesive is used can secure a space for irradiating light from the radial direction opposite to the collimator lens bonding portion, other than above the collimator lens.
[0035]
Therefore, the degree of freedom in the light irradiation direction is increased, and the assembling workability is improved, and at the same time, the curing time can be shortened, and the cost can be reduced by the assembling process.
[0036]
At this time, it is also effective to obtain a light collecting effect such that light incident on the arc portion of the collimator lens irradiates the adhesive portion facing the incident portion, and the reliability of curing the adhesive is further improved.
[0037]
It is preferable that the protrusions are arranged symmetrically with respect to a line passing through the center of a plurality of lens optical axes and perpendicular to the arrangement direction of the collimator lenses.
[0038]
In the above configuration, the direction and amount of change of each beam irradiation position due to the deformation of the holding unit that holds the collimator lens can be made equal, and the relative difference between the optical axis shifts can be reduced.
[0039]
BEST MODE FOR CARRYING OUT THE INVENTION
Preferred embodiments of the present invention will be illustratively described in detail below with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention thereto unless otherwise specified. Absent.
[0040]
An embodiment will be described with reference to FIGS. In the present embodiment, a multi-beam light source device R1 used in a multi-beam scanning optical device S as shown in FIG. 6 will be described. Since the multi-beam scanning optical device S is the same as that described in the related art, the description is omitted.
[0041]
FIG. 1 is a schematic diagram showing a configuration of a multi-beam light source device R1 according to the present embodiment that best represents the present invention. FIG. 2 is a schematic sectional view showing the configuration of the multi-beam light source device R1 according to the present embodiment that best represents the present invention.
[0042]
The first semiconductor laser 1a is a semiconductor laser as a light source. The second semiconductor laser 1b is a semiconductor laser similar to the first semiconductor laser 1a.
[0043]
The holder member 2 holds the semiconductor lasers 1a and 1b and collimator lenses 3a and 3b described later.
[0044]
The first collimator lens 3a forms the laser light into substantially parallel light. The second collimator lens 3b is similar to the first collimator lens 3a.
[0045]
The laser drive circuit board 4 is for emitting the semiconductor lasers 1a and 1b.
[0046]
In the holder member 2, press-fit holes 21a and 21b for holding the semiconductor lasers 1a and 1b, cylindrical portions 22a and 22b for holding the collimator lenses 3a and 3b, and a clamp tool 5 for holding the collimator lenses 3a and 3b (FIG. 3), a first cutout portion 23 serving as a movable region, a projection portion 25 serving as an adhesion portion of the collimator lenses 3a and 3b, and an ultraviolet curing adhesive 8 filled with the collimator lenses 3a and 3b and the projection portion 25. A second notch 24 used to pour the adhesive into the gap between the engaging portions, optical apertures 26a and 26b for forming the laser beam into a predetermined shape, and a mounting portion 27 for fixing the laser drive circuit board 4 by screws. And a mounting portion 28 for screw-fixing the integrated multi-beam light source device R1 to a housing of a scanning optical device (not shown).
[0047]
The protrusion 25 is divided into three equal parts on the outer periphery of each of the collimator lenses 3a and 3b, and has a protrusion shared between the arrangement directions of the collimator lenses 3a and 3b.
[0048]
The collimator lenses 3a and 3b include outer peripheral surfaces 31a and 31b that are directly bonded to the holder member 2.
[0049]
In the above configuration, the semiconductor lasers 1a and 1b are fixedly held in the press-fit holes 21a and 21b of the holder member 2 by press-fitting.
[0050]
The lead pins 11a and 11b of the semiconductor lasers 1a and 1b are fixed to the laser drive circuit board 4 by soldering.
[0051]
On the other hand, the laser drive circuit board 4 is fastened to the holder member 2 by screwing the screw 7 into the mounting portion 27.
[0052]
The collimator lenses 3a and 3b are held by a clamp tool 5 (shown in FIG. 3) inserted from the first cutout portion 23 in such a manner that the bonding portions of the collimator lenses 3a and 3b of the holder member 2 are oriented vertically. The focal length and the irradiation position of the laser light emitted from the semiconductor lasers 1a and 1b are adjusted to predetermined positions in three axes (X, Y, Z) directions.
[0053]
At this time, the depth of the second notch 24 in the optical axis direction is closer to the center of the outer peripheral surfaces 31a, 31b of the collimator lenses 3a, 3b than the adjustment positions of the collimator lenses 3a, 3b in FIG. In addition, the tip of the projection 25 protrudes from the exit surfaces of the collimator lenses 3a and 3b.
[0054]
The second cutout portion 24 is filled with the ultraviolet curable adhesive 8, and flows into the gap between the holder member 2 and the collimator lenses 3a, 3b by its own weight and flows around.
[0055]
An adhesive is filled between the second cutout portion 24 and the engaging portion, and the collimator lenses 3a and 3b are bonded and fixed in a state of being irradiated with ultraviolet rays.
[0056]
Then, the clamp tool 5 retreats after the collimator lenses 3a and 3b are fixed by bonding.
[0057]
As described above, the components are integrated to form the multi-beam light source device R1.
[0058]
As shown in FIGS. 1 and 2, in the present embodiment, the second cutout portion 24 is provided with three projections 25 for each of the collimator lenses 3a and 3b, but the number thereof is not limited. What is necessary is just to arrange | position to the circumference of each collimator lens 3a, 3b, a circumference equally, or the opposing surface side of the 1st notch part 23. Further, they may be arranged symmetrically about the center line OO of the holder member 2.
[0059]
The three projections 25 holding the collimator lenses 3a and 3b, respectively, disperse the behavior of the collimator lenses 3a and 3b in the circumferential direction in a well-balanced manner due to curing contraction by an adhesive or thermal expansion of the holder member 2. Thus, the direction of the displacement of the collimator lenses 3a and 3b can be stabilized, and the amount of fluctuation can be reduced. Therefore, the fixing accuracy is improved, and the relative displacement of each lens optical axis can be suppressed.
[0060]
At this time, since at least one projection 25 holding the collimator lenses 3a and 3b is shared, the distance between the optical axes can be designed to be narrower, so that the sensitivity on the optical image plane is reduced. It is possible to reduce and at the same time to make it compact.
[0061]
Next, as shown in FIG. 4, the irradiation direction of the ultraviolet light P for curing the adhesive is the vertical direction of the holder member 2 and the second direction provided by the cylindrical portions 22a and 22b to which the collimator lenses 3a and 3b are bonded. Irradiation can be performed from the side opposite to the notch 24, so that the number of bonding parts and the part in the irradiation direction can be set arbitrarily, and bonding can be performed in a short time. Is also possible.
[0062]
In fixing the collimator lenses 3a and 3b by irradiating ultraviolet rays, since the vicinity of the bonding portion is open, the air permeability is excellent. In addition to preventing the heat from being stuck by the adhesive and the holder member 2, the bonded portions of the collimator lenses 3a and 3b disperse the deformation due to thermal expansion equally around the circumference, so that the relative positions of the respective collimator lenses 3a and 3b are relatively large. Suppress misalignment.
[0063]
Therefore, when the first and second cutouts 23 and 24 come into contact with the outside air, the behavior of the collimator lenses 3a and 3b due to the heat of the curing reaction of the adhesive and the thermal expansion of the holder member 2 can be suppressed to a minimum, and the time is short. As a result, the optical performance can be stabilized, so that high-precision bonding can be achieved.
[0064]
The holding of the collimator lenses 3a and 3b shown in FIG. 2 is made up of the second cutout portion 24 and the holder member 2 and the engaging portions of the outer peripheral surfaces 31a and 31b of the collimator lenses 3a and 3b. And the plurality of projections 25 hold the collimator lenses 3a and 3b, so that the adhesive strength is improved. In addition, the effect is better obtained when each bonding surface is roughened.
[0065]
Further, the plurality of projections 25 uniformly hold the collimator lenses 3a and 3b from the outer peripheral direction and have sufficient rigidity, so that the optical characteristics are deteriorated due to deformation of the holder member 2 due to an environmental change or thermal expansion. And can be stabilized at the same time.
[0066]
In FIGS. 1 and 2, the bonding portion of the collimator lenses 3a and 3b is formed by an engagement portion between the outer peripheral surfaces 31a and 31b of the collimator lenses 3a and 3b and the inner circumference of the cylindrical portions 22a and 22b. As shown in (1), after the collimator lenses 3a and 3b are once adhered and fixed to the holder member 2, an adhesive is applied to the outgoing surface side outside the effective diameter (broken line portion), and the collimator lens 3a is formed again. , 3b can be strengthened while maintaining the bonding position, and the reliability can be further improved by suppressing the displacement of the collimator lenses 3a, 3b.
[0067]
In the unitized multi-beam light source device R1, as shown in FIG. 2, the projection 25 holding the collimator lenses 3a, 3b protrudes from the exit surface side of the adhesively fixed collimator lenses 3a, 3b. Further, since the collimator lenses 3a and 3b are protected without being opened, an operator or the like may erroneously touch the lens surface to make the lens surface dirty, or may be subjected to an external impact during work in an assembling process or during assembly of the unit. The deterioration of optical characteristics is prevented.
[0068]
In the present embodiment, an ultraviolet-curable adhesive is used, but another light-curable adhesive may be used. The light beam emitted from the semiconductor laser may have one or a plurality of light emitting points, and is arbitrary.
[0069]
【The invention's effect】
As described above, the present invention can stabilize the fixing accuracy and reduce the relative displacement of the collimator lens by holding each collimator lens at a plurality of portions. Further, in addition to increasing the bonding strength of the collimator lens and the rigidity of the bonding portion, since it is protected from external contact and impact, a more reliable multi-beam laser light source device can be obtained.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing a multi-beam light source device according to an embodiment.
FIG. 2 is a schematic sectional view showing a multi-beam light source device according to an embodiment.
FIG. 3 is a schematic diagram illustrating a collimator lens adjustment of the embodiment.
FIG. 4 is a schematic view showing a collimator lens bonding step of the embodiment.
FIG. 5 is a schematic view showing another example of the collimator lens bonding portion of the embodiment.
FIG. 6 is a schematic diagram showing a multi-beam scanning optical device.
FIG. 7 is a schematic diagram showing a conventional multi-beam light source device.
[Explanation of symbols]
1a First semiconductor laser 1b Second semiconductor laser 2 Holder member 3a First collimator lens 3b Second collimator lens 4 Laser drive circuit board 5 Clamp tool 7 Screw 8 Ultraviolet curing adhesive 11a, 11b Lead pins 21a, 21b Press-fit holes 22a, 22b Cylindrical portion 23 First cutout portion 24 Second cutout portion 25 Projection portions 26a, 26b Optical aperture 27 Mounting portion 28 Mounting portions 31a, 31b Outer peripheral surface

Claims (5)

A light source including: a plurality of semiconductor lasers serving as a light source; a collimator lens that converts each laser beam emitted from the semiconductor laser into substantially parallel light; and a holder member that holds a plurality of sets of the semiconductor laser and the collimator lens. In the device,
The holder member includes a cylindrical portion that holds each of the collimator lenses,
The cylindrical portion has a plurality of first notches penetrating the inner and outer circumferences,
A light source device, wherein projections formed between the first cutouts and holding the collimator lens are arranged at equal circumferential intervals with respect to the outer periphery of each of the collimator lenses. The light source device according to claim 1, further comprising a second cutout portion used for filling the adhesive on the protrusion. The light source device according to claim 1, wherein at least one of the plurality of protrusions supporting the collimator lens is shared. 4. The light source device according to claim 1, wherein the protrusion is disposed on a side facing the first cutout. 5. The light source according to any one of claims 1 to 4, wherein the protrusions are arranged symmetrically with respect to a line passing through a center of a plurality of lens optical axes and perpendicular to an arrangement direction of the collimator lenses. apparatus.

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