JPH01319716A - Adhered structure of lens - Google Patents

Abstract

PURPOSE:To decrease the errors of an optical system and to improve the accuracy thereof by providing adhesive surfaces to plural pieces of lenses exclusive of the light transmission surfaces thereof and coating an adhesive agent to the recesses in the frame of the outer peripheral part, thereby adhering the lenses. CONSTITUTION:The molded plastic lenses 5a', 5b', and 7a', 7b' are adhered at top and bottom by the adhesive agent 6. Although the upper lenses 5a', 7a' are not particularly worked at the base, the recesses 5c', 7c' are provided to the central part of the front surfaces of the lower lenses 5b', 7b' and frame parts 5d', 7d' are formed to the circumference of the front surfaces. The adhesive agent 6 is applied to several points of the recesses and the lenses are superposed on top and bottom and are irradiated with UV rays from the outside to cure the adhesive agent. Since the UV curing type adhesive agent develops the max. adhesive effect at about 100mum thickness, the depth of the recesses 5c', 7c' is set at about 100mum with respect to the frame parts 5d', 7d'. The frame parts 5d', 7d' constitute the reference planes for adhesion and prevent the outflow of the adhesive agent to the outside; therefore, the adhesion with good accuracy is executed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an adhesive structure for lenses constituting an optical system of a scanning optical device such as a laser printer or a laser copying machine.

[Prior Art] In recent years, it has become desirable for laser printers and laser copying machines to print in multiple colors and to print in more detail. It is necessary to scan the photoreceptor using a light source. For this purpose, for example, it is conceivable to simply combine a plurality of conventional scanning optical devices each having a single light source. However, this method requires a considerably large machine and is expensive in terms of cost, so it is not practical.
Conventionally, it has been considered that multiple light sources are installed in one scanning optical device, and the optical system for scanning the light beams emitted from these light sources is shared and arranged in one optical frame. ing.

FIG. 5 is a perspective view showing the configuration of the optical system of the scanning optical device as described above, in which a plurality of light sources 1a and 1b have collimator lenses 2a and 2b, a cylindrical lens 3a, 3b are arranged in sequence.

Furthermore, a rotating polygon mirror 4 is commonly installed on the optical axis extension of the cylindrical lenses 3a and 3b, and the reflection direction of this rotating polygon mirror 4 has different f and θ characteristics at the top and bottom corresponding to the respective optical ray axes. The first imaging lens 5 is formed by integrally molding the lenses 5a and 5b with the adhesive 6, and the lens 7a is similarly formed.
, 7b integrally molded, a second imaging lens 7, and a photoreceptor 8.
are arranged sequentially.

Here, the lenses 5a and 5b and 7a and 7b are bonded together simply by the adhesive 6 by overlapping their boundary surfaces. Therefore, the light beam B emitted from the light sources 1a and 1b
1 and B2 are scanned by a rotating polygon mirror 4 via collimator lenses 2a and 2b and cylindrical lenses 3a and 3b, and are scanned by a photoreceptor 8 via a first imaging lens 5 and a second imaging lens 7. irradiated on top.

However, in the method of simply bonding two lenses 5a and 5b and 7a and 7b with adhesive 6 as described above, if the amount of adhesive 6 is too large when the lenses are overlapped,
As shown in the figure, there is a disadvantage that the adhesive 6 flows out to the side surfaces and adheres particularly to the side surfaces of the lower lenses 5b and 7b. Additionally, if the amount of adhesive 6 is small, there is a drawback that strong and uniform adhesion cannot be achieved, and the amount of adhesive 6 causes distortion in the optical system, reducing the accuracy of the image obtained on photoreceptor 8. .

Furthermore, as shown in FIG. 6, there is a possibility that the adhesive 6 is applied unevenly between the lenses 7a and 7b, and in this case, since the lens 7a is tilted, the light beam B1 may be applied to the photoreceptor. Even if the scanning line S2 formed on the light beam B1 is not curved, the scanning line S1 formed by the light beam B1 is curved. Therefore, for example, two light beams B1. In the case of a machine that performs two-color development using B2, there is also the problem that color shift occurs in the resulting image. Although FIG. 6 shows only the case of lenses 7a and 7b, lens 5
A similar problem exists for a and 5b.

[Object of the Invention] The object of the present invention is to eliminate the drawbacks of the above-mentioned conventional examples, and to provide a method that enables lenses to be bonded together using an adhesive uniformly and firmly, without causing errors in the optical system, and with high precision. The purpose of the present invention is to provide an adhesive structure for lenses.

[Summary of the Invention] J: The gist of the present invention for achieving the above-mentioned object is to provide a lens structure in which a plurality of lenses have an adhesive surface formed in addition to the light transmitting surface, and these adhesive surfaces are overlapped. This lens bonding structure is characterized in that a frame-shaped outer circumferential portion is provided on the bonding surface, and an adhesive is applied to a recessed portion surrounded by the outer circumferential portion for bonding.

[Embodiments of the Invention] The present invention will be described in detail based on embodiments illustrated in FIGS. 1 to 4.

FIG. 1(a) is a perspective view of a device similar to the scanning optical device shown in FIG. 5 constructed using the lens bonding structure according to the present invention, and FIG. 1(b) is a cross-sectional view of the bonded lens. The configuration other than the bonded portions of lenses 5a' and 5b' and 7a' and 7b' is the same as that shown in FIG. 5, so a description of the same components will be omitted.

The lenses 5a', 5b', and 7a', 7b' are molded plastic lenses made of, for example, acrylic resin, and are bonded vertically with an adhesive 6. Upper lens 5a
As shown in FIG. 1(b), ' and 7a' are not particularly processed on the bottom surface, but the lower lenses 5b' and 7b
Recesses 5c' and 7c' are provided in the center of the upper surface, respectively, and a frame 5d° is provided around the upper surface.

7d' is formed. Apply an adhesive 6, such as an ultraviolet curing adhesive, to several places in the recesses 5c' and 7c', and attach the lenses 5a', 5b', and 7a' from above and below, as shown in FIG. 1(b). Overlap 7b'.

Then, the adhesive 6 is cured and fixed by irradiating ultraviolet rays from the outside. The thickness of UV-curable adhesive is LOOp
It has the greatest adhesion effect when applied at a thickness of about m.
It is optimal that the depth of the recesses 5c', 7c' from the frame parts 5d'', 7d'' is approximately loO#Lm.

In this way, the recesses 5c' are formed in the lower lenses 5b' and 7b'.
, 70'', the frame portions 5d' and 7d' serve as reference surfaces when bonding the upper and lower lenses, and also serve as reference surfaces for bonding the upper and lower lenses.
It acts as a barrier to prevent the adhesive from flowing out to the sides, and furthermore, the adhesive 6
It also plays the role of a guide portion that spreads the lenses 5b' and 7b' in the longitudinal direction. Furthermore, when overlapping the lenses 5a'' and 5b' and 7a' and 7b', the adhesive 6 does not adhere to the frame parts 5d' and 7d' where the two lenses directly contact each other, and the adhesive 6 is not actually adhered. Since the only portions that are exposed are the concave portions 5c' and 7c', it is possible to prevent the lens from being tilted due to uneven thickness of the adhesive 6.

Furthermore, when using a lens made of a material that is easy to work with, such as a plastic lens, as shown in FIG. Therefore, it is also easy to provide positioning guide convex portions 10a at both ends of the upper lens 10 and guide recesses 11a at both ends of the lower lens 11. By providing the guide portions 10a and lla in this way, assembly efficiency can be improved.

Note that such an adhesion method is not limited to acrylic resin lenses, but can also be applied to glass lenses, etc. However, in the case of glass lenses, it is extremely difficult to provide the above-mentioned recesses in terms of processing. For this reason, FIG. 3 is a perspective view of a third embodiment applied to a lens made of a material that is difficult to work with, such as a glass lens, and the bottom surface of the upper lens 12 and the upper surface of the lower lens 13 remain merely flat. Not processed. However, a frame-shaped guide frame 14 that follows the shape of the upper lens 12 and the lower lens 13 is inserted between the upper lens 12 and the lower lens 13, and the adhesive 6 is applied at multiple locations on the upper surface of the lower lens 13 within the guide frame 14. , upper and lower lenses 12.13 are superimposed. If the thickness of this guide frame 14 is set to about 100 lm, which is the same as the depth of the recesses 5c' and 7c' in the first embodiment, the adhesive effect will be maximized, and the adhesive 6 will not flow out around the upper and lower parts. It is possible to prevent the lenses 12.13 from tilting. If the guide frame 14 is used in this way, there is no need to perform special processing on the joint surfaces of the upper and lower lenses 12 and 13, so it is possible to easily maintain a good bonding state even when lenses are made of materials that are difficult to work with, such as glass lenses. can be obtained.

Next, FIG. 4 is a perspective view of a fourth embodiment, which is a partially modified version of the third embodiment shown in FIG. Guide walls 14a' are provided at both ends to guide the bonding positions of the upper and lower lenses 12 and 13. Then, as in the third embodiment, adhesive 6 is applied on the lower lens 13 inside the guide frame 14', and the upper and lower lenses 12.
13 are overlapped with each other via a guide frame 14'. With this structure, positioning of the upper and lower lenses 12 and 13 becomes easy, so that assembly efficiency can be further improved.

[Effects of the Invention] As explained above, the lens adhesive structure according to the present invention has the following effects:
The outer periphery is formed into a frame shape, adhesive is applied to the recessed part of the outer periphery, and bonding is performed by overlapping the adhesive surfaces, so there is no risk of the adhesive leaking to the side of the lens or causing any damage to the adhesive. It becomes possible to prevent the lens from being tilted due to uniform coating, and it is possible to reduce errors in the optical system constituting the scanning optical device and the like, and improve the accuracy of the optical system.

[Brief explanation of the drawing]

1 to 4 show an embodiment of the lens adhesive structure according to the present invention, FIG. 1(a) is a perspective view of the first embodiment applied to an optical scanning device, and FIG. 1(b) is a perspective view thereof. Partial sectional view, 2nd
The figure is a perspective view of the second embodiment. FIG. 3 is a perspective view of the third embodiment, FIG. 4 is a perspective view of the fourth embodiment, FIG. 5 is a perspective view of a conventional optical scanning device, and FIG. 6 is an explanatory diagram of its operation. It is. Symbols 5a', 5b', 7a', and 7b' are lenses, 50'
. 7c' is a recess, 5d' and 7d' are frame parts, 6 is adhesive, 1
0.12 is the upper lens, 11.13 is the lower lens, 10
a is a guide convex portion, lla is a guide concave portion, 14.14° is a guide frame, and 14a' is a guide wall portion. Patent applicant Canon Co., Ltd.

Claims (1)

[Claims] 1. Forming an adhesive surface on multiple lenses other than the light transmitting surface,
In a lens structure in which these adhesive surfaces are overlapped, a frame-shaped outer periphery is provided on the adhesive surface, and an adhesive is applied to a recess surrounded by the outer periphery to bond the lens. Adhesive structure.