JP3015120B2 - How to attach a synthetic resin lens - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for mounting a synthetic resin lens used in a laser printer or the like.

[0002]

2. Description of the Related Art In recent years, it has become common to use a synthetic resin lens for a lens group of a scanning optical system used for a laser printer or the like. FIG. 5 shows a scanning optical system, in which a laser beam incident from a laser beam generating unit 1 is deflected and scanned by a rotary polygon mirror 3 via a cylindrical lens 2 and fθ
The light passes through the lens 4 and becomes uniform light to form an image on the photosensitive drum 5. The lens group such as the fθ lens 4 used here has been manufactured from optical glass until now. However, due to high cost and difficulty in manufacturing a lens having a complicated shape,
Synthetic resins that are low in cost and easy to mold have become widespread as materials.

[0003] As a method for fixing a synthetic resin lens, screwing through a sheet metal or bonding with an adhesive is generally used. At present, the most effective method for fixing a synthetic resin lens is an ultraviolet curing adhesive. It was adhesive. In many cases, bonding is performed on the entire surface or a plurality of small bonding surfaces in a state where the side surface of the synthetic resin lens 4 abuts against a positioning projection 7 provided on the mounting substrate 6.

[0004]

However, in the above-mentioned conventional example, it is necessary to provide the projection 7 for positioning the synthetic resin lens 4. The projection 7 has no purpose other than positioning, and has no advantage in the optical performance of the lens 4. In addition, in consideration of miniaturization of the entire scanning optical system, it may become an obstacle to miniaturization of the lens 4.

[0005] Further, the difference in the material of the lens 4 and the mounting substrate 6 causes a difference in the amount of expansion due to the difference in the coefficient of thermal expansion between the members. 4 will cause distortion and deformation, which significantly reduces the performance of the optical system. In addition, a wide adhesive surface increases the amount of adhesive used and prolongs the curing time of the adhesive, so that it is necessary to increase the performance of the device for curing the adhesive, leading to an increase in cost. come.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned drawbacks, to make the scanning optical system compact,
An object of the present invention is to provide a method of attaching a synthetic resin lens that does not degrade the performance of the lens.

[0007]

According to the present invention, there is provided a method of mounting a synthetic resin lens, comprising: holding a synthetic resin lens by a jig; and pressing a predetermined position of a mounting member by the jig. Meanwhile, only a part of the bottom of the synthetic resin lens at the substantially central portion is fixed to the mounting member with an adhesive, and the jig is withdrawn after the adhesive is solidified.

[0008]

In the method of mounting a synthetic resin lens having the above-described configuration, the mounting position of the synthetic resin lens is determined accurately by using a jig without using a positioning protrusion. There is no need to provide a part that fits with the positioning protrusion on the synthetic resin lens, and the lens only needs to have its own function, and the size of the scanning optical device can be reduced.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the embodiments shown in FIGS.

FIG. 1 is a perspective view for explaining the method of the first embodiment, and FIG. 2 is a sectional view of a mounting substrate and a synthetic resin lens. In FIG. 1, a substantially plate-shaped synthetic resin lens 11 is arranged on a mounting substrate 10, and a jig 12 attached to an automatic machine tool is arranged above the synthetic resin lens 11. Jig 12
Is for transporting the synthetic resin lens 11, performing accurate positioning, and crimping the synthetic resin lens 11,
The jig 12 has a lens holding part 13 for holding the synthetic resin lens 11 and a lens crimping part 14.

The jig 12 automatically moves to a predetermined position on the mounting substrate 10 while holding the synthetic resin lens 11 by the lens holding portion 13. A small amount of an ultraviolet curable adhesive is applied to an adhesive surface 15 that adheres the mounting substrate 10 and the synthetic resin lens 11. After applying the ultraviolet curing adhesive, the synthetic resin lens 11 is accurately placed on the mounting substrate 10 and the jig 12
Is pressed against the mounting substrate 10 by the lens pressing portion 14. In this state, ultraviolet irradiation is performed, and the pressing of the synthetic resin lens 11 by the jig 12 continues until the ultraviolet curing adhesive is completely cured. Then, after the ultraviolet-curing adhesive is cured, the jig 12 is moved up by lifting the jig 12 upward.

In this embodiment, unlike the conventional example, there is no need to provide a positioning protrusion for the lens on the mounting substrate 10, and a structure for fixing the synthetic resin lens 11 itself is not required, so that a compact lens can be designed. Also, adhesive surface 1
5 is about 20 to 30% of the total area under the synthetic resin lens 11, and the thickness of the adhesive is also about several μm, so that the inclination and the like of the synthetic resin lens 11 due to adhesion can be suppressed as much as possible. By reducing the area of the bonding surface 15 and reducing the thickness of the adhesive, the influence of thermal expansion and expansion and contraction due to temperature changes can be suppressed. In addition, it is desirable to use an adhesive having low viscosity in order to reduce the thickness of the adhesive.

FIG. 3 shows a mounting board 1 according to a second embodiment.
0 is a sectional view of the synthetic resin lens 11. Mounting board 10
The method of mounting the synthetic resin lens 11 is almost the same as that of the first embodiment. In the second embodiment, the mounting substrate 1
The lens mounting surface of No. 0 is flat in the first embodiment, but has irregularities. That is, the bonding surface 15 of the mounting substrate 10 to which the synthetic resin lens 11 is bonded is slightly protruded from the reference height of the mounting substrate 10, and the partial support surface 16 supporting both ends of the synthetic resin lens 11 is bonded to the bonding surface 15.
It is molded so as to protrude only slightly. Since the partial support surface 16 has only a role to support the synthetic resin lens 11, care must be taken so that the ultraviolet curing adhesive is not applied to the partial support surface 16.

When the synthetic resin lens 11 is attached to the mounting substrate 10 with an ultraviolet-curing adhesive applied only to the bonding surface 15, the ultraviolet-curing adhesive has a property of contracting slightly upon curing. The synthetic resin lens 11 is attracted to the mounting substrate 10 and generates a stress on the partial support surface 16. This stress is applied to the mounting board 1
Since the fixing of the synthetic resin lens 11 to 0 is strengthened, the area of the bonding surface 15 can be reduced.

The shrinkage of the UV curable adhesive causes a stress between the mounting substrate 10 and the synthetic resin lens 11, but the thickness of the UV curable adhesive on the bonding surface 15 is very small. Synthetic resin lens 11 caused by
Degradation of optical performance due to deformation of can be ignored. However, in the bonding process, it is important to control the application amount of the ultraviolet curing adhesive and control the processing accuracy of the partial support surface 16 and the like.

The effect of thermal expansion in the direction of the bonding surface of the synthetic resin lens 11 is due to the fact that the partial support surface 16 is not bonded.
The mounting substrate 10 and the synthetic resin lens 11 can have their own thermal expansion and can be ignored. Therefore, the method of the second embodiment is effective for a scanning optical system that requires high precision and high quality. Further, in the second embodiment, the partial support surface 16 is provided on the mounting substrate 10, but the same effect can be obtained by providing the partial support surface 16 on the synthetic resin lens 11.

FIG. 4 is a perspective view of a third embodiment of the present invention. Unlike the first and second embodiments, the synthetic resin lens 1 is different from the first and second embodiments.
The first adhesive surface 15 is the bottom surface of the thin projection 17 projecting from the lower center of the synthetic resin lens 11. Synthetic resin lens 11
Is positioned by the jig 12 as in the previous embodiment, and the ultraviolet curing adhesive is applied to the bottom surface of the thin projection 17.

Also in the third embodiment, since the fixing of the synthetic resin lens 11 to the mounting substrate 10 is based on the bonding of only the bonding surface 15 in a narrow range, no distortion occurs. In addition, by increasing the distance between the thin projection 17 and the effective lens portion, it is possible to suppress the propagation of distortion to the effective lens portion due to adhesion. In addition, the thin protrusion 1
By reducing the thickness of 7, it is possible to increase the transmittance of ultraviolet rays and shorten the bonding process time.

[0019]

As described above, in the method of mounting a synthetic resin lens according to the present invention, since the mounting position of the synthetic resin lens is determined using a jig, it is necessary to provide positioning protrusions on the mounting member and the synthetic resin lens. Therefore, the size of the synthetic resin lens can be reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating a mounting method according to the present invention.

FIG. 2 is a cross-sectional view of an attached state.

FIG. 3 is a sectional view of a second embodiment.

FIG. 4 is a perspective view of a third embodiment.

FIG. 5 is a perspective view of a conventional scanning optical system.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Mounting board 11 Synthetic resin lens 12 Jig 13 Lens holding part 14 Lens crimping part 15 Adhesive surface 16 Partial support surface 17 Thin protrusion

Claims (3)

(57) [Claims] 1. A synthetic resin lens is held by a jig, and only a part of a seating surface at a substantially central portion of the synthetic resin lens is pressed by an adhesive to a predetermined position of the mounting member with an adhesive. Wherein the jig is removed after the adhesive is solidified. 2. The synthetic resin lens mounting method according to claim 1, wherein the synthetic resin lens or the mounting member is provided with a plurality of partial support surfaces slightly projecting from a portion to which the adhesive is applied. 3. A thin projection is provided at a lower center of the synthetic resin lens, and the adhesive is applied to a bottom surface of the projection.
The method for mounting a synthetic resin lens according to claim 1, wherein the synthetic resin lens is fixed.