JP3422710B2 - Optical lens joining device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical lens joining device, and more particularly to an optical lens joining device in which an optical lens is incorporated into a lens barrel by using a joining member such as an integral plastic ring.

[0002]

2. Description of the Related Art In recent years, laser printers, copiers,
With the expansion of laser application fields such as laser microscopes, there has been a demand for higher resolution and higher accuracy of laser application devices. In order to achieve such high resolution and high accuracy, it is necessary to stably narrow the laser beam diameter over a wide scanning width. In general, a microscope has a narrow field of view when the resolution is increased, and a laser microscope is no exception. Further, in order to realize high resolution, for example, high performance of a laser scanner or the like is required. Therefore, in the optical system, it is important to improve the accuracy of the scanning lens that images the laser over a wide scanning width.

FIG. 6 shows a longitudinal sectional view of a scanning lens system in the prior art. The lens barrel 600 is provided with lenses 61 to 66 in order from the laser incident direction on the right side in the figure. The lenses 61 to 66 are cemented in the lens barrel 600 by a cementing method. Each of these lenses 6
Reference numerals 1 to 66 are for making a laser enter from the direction of arrow 1 and passing it through to form an image on the image point 3 on the image plate 2.

[0004]

In order to realize the high resolution and high accuracy as described above, it is necessary to position the scanning lens group with high accuracy. However, in the prior art, since the method of joining the scanning lens group and the lens barrel is basically clearance fit, each lens may be decentered at the time of joining. Therefore, conventionally, there has been a limit in the precision of laser focusing. Further, with this method, mass production is difficult, and in addition, each lens is likely to be decentered at the time of joining, so that the imaging accuracy of the laser is limited. Further, since there is a large difference in the coefficient of thermal expansion between the lens and the lens barrel, the lens is affected by the temperature change, and the imaging performance is further deteriorated.

In the present invention, in order to minimize the eccentricity of the lens, an optical lens joining device by shrink fit using a shrink fitter (joining member) is provided as an example to improve the resolution of laser application devices. The purpose is to achieve high precision.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an optical lens joining device capable of joining lenses by an interference fit by using a joining member made of a polymer material which is integral with the lens group and the lens barrel. . SUMMARY OF THE INVENTION It is an object of the present invention to provide an optical lens joining device to which an interference fit can be applied even if the lens groups in the lens barrel have different diameters or the same diameter, different shapes or the same shape, and plural or singular shapes. . Further, according to the present invention, an optical lens joining device capable of accurately positioning the axial distance of the lens at the time of inserting the lens group into the joining member and then incorporating the lens in the lens barrel is provided. The purpose is to provide. Further, it is an object of the present invention to provide an optical lens joining device capable of improving decentering of a lens and easily disassembling and reassembling.

[0007]

According to the solution of the present invention, a first optical lens having a first diameter, and a second optical lens having a diameter different from the diameter of the first optical lens, A lens barrel that houses the first and second optical lenses therein, and a polymeric material having a coefficient of thermal expansion larger than that of the lens barrel, corresponding to the diameters of the first and second optical lenses. There is provided an optical lens joining device having joining portions having different inner diameters and including a joining member for joining the lens barrel and the first and second optical lenses.

[0008]

1 is a longitudinal sectional view of a first embodiment of an optical lens joining device according to the present invention. Here, the scanning lens group and the like will be described as an example, but the present invention is not limited to this and can be applied to various optical devices such as laser application devices. In addition, the dimensions in the drawings are examples and are not limited thereto.

The optical lens joining device in FIG. 1A comprises a lens barrel 100, scanning lens groups 11 to 16 and shrink fitters (joining members) 110 and 111. The lens barrel 100 can be formed of a metal such as aluminum. The lens barrel 100 includes lenses 11 to 16 and shrink fitters 110 and 111 in order from the direction in which the laser enters (for example, the right side in the drawing). Each lens 1
Although a plurality of 1 to 16 are provided in this figure, the number can be changed as appropriate and may be one. The lenses 11 to 16 are cemented in the lens barrel 100 by shrink fitters 110 and 111. The diameters of the lenses 11 to 16 may be different or the same, and the shape of the lenses 11 to 16 may be an appropriate shape such as convex or concave.

The shrink fitters 110 and 111 are
It is a cylindrical mechanical element made of a polymer material having a thermal expansion coefficient larger than that of a lens barrel 100 made of a metal such as aluminum. Here, as an example, heat-resistant polymer material such as polyimide or acrylic is used as a material. In the optical lens joining device of the present invention, by using such shrink fitters 110 and 111, it is possible to apply an interference fit. The shrink fitter 111 has grooves 120 and 121 in the outer circumferential direction surrounding the lens group, but the grooves 120 and 121 can be provided as needed. In this embodiment, the groove 120
And 121 are shown, and grooves 120 and 12 are shown.
Reference numeral 1 is for fixing the shrink fitter 110 that joins the lens groups by passing a wire or string. Also, the shrink fitter 110 or 1
A slit 11 may be provided in the radial direction of the lens group. The slit may be formed so as to completely divide the shrink fitter, or may be partially left and not divided. By providing the above-described slits in the shrink fitters 110 and 111 in the radial direction and optimizing the thickness of the shrink fitters 110 and 111, the thermal expansion in the radial direction of the lens can be effectively utilized and the shrinkage can be reduced. Can be prevented. In addition,
Although the eccentricity of the lens decreases as the shimeshiro is increased,
The spherical surface of the lens is largely deformed and the imaging accuracy is deteriorated. Therefore, if optimal dimension design is performed, the interference can be made constant regardless of the temperature change, and the interference fit can be applied to the joining of optical components. The setting of this interference can be obtained by, for example, a three-dimensional FEM analysis.

FIG. 1B is a partially enlarged view of the optical lens joining device according to the present invention. 1 (B) is shown in FIG. 1 (A).
3 is a partially enlarged view of a part surrounded by a broken line in FIG. Figure 1 (B)
The inner lens 16 is concave on both sides and has a wide joint surface, so that it is likely to be deformed by a slight tightening pressure. In order to prevent such deformation, as shown in the figure, a joint surface 130 that is narrower than the outer peripheral thickness of the lens is provided so that the joint width of the shrink fitter 111 and the lens 16 is smaller than the thickness of the lens. The joint surface is concentrated on the part where the lens is difficult to deform. Such a joint surface 130 can be provided for a lens having an appropriate shape at an appropriate position.

FIG. 2 shows a vertical sectional view of a second embodiment of the optical lens joining device according to the present invention. The optical lens joining device in FIG. 2 includes a lens barrel 200, lens groups 21 to 26, and a shrink fitter 210. The lens barrel 200 and the lens groups 21 to 26 of the optical lens joining device of FIG.
The material and configuration of the shrink fitter 210 are shown in FIG.
The same as in the case of is used. However,
In FIG. 2A, the shrink fitters 110 and 111 are separated, but the shrink fitter 21 in FIG.
0 is different in that it is an integrated type.

The lens barrel 200 includes lenses 21 to 26 and a shrink fitter 210 in order from the direction in which the laser enters (for example, the right side in the drawing). Each lens 21-
Although there are a plurality of 26 as in the case of FIG. 1A described above, the number can be appropriately changed and may be one, and the diameter of the lens can be different or the same. Furthermore, the shape of the lens can be convex or concave. The shrink fitter 210 has grooves 220 and 221 in the outer circumferential direction surrounding the lens group. In addition, dimensions such as the part where the lens 26 is tightened and the inner and outer diameters are
The shape is the same as in the case of FIG. 1 in which the shrink fitters 210 are individually separated, and the shrink fitters 210 can be manufactured without slits without considering the temperature change.

FIG. 2B is a partially enlarged view of the optical lens joining device according to the present invention. 2 (B) is shown in FIG. 2 (A).
3 is a partially enlarged view of a part surrounded by a broken line in FIG.

The lens 26 in FIG. 2B is the same as that shown in FIG.
Similarly, since both sides are concave, a slight tightening pressure causes deformation. In order to prevent such deformation, Fig. 1
Similar to (B), the joint surface 230 as shown is provided,
The shrink width of the shrink fitter 210 and the lens 26 is smaller than the thickness of the lens.

Next, the result of comparison between the present invention and the prior art will be described. FIG. 3 is a block diagram of an experimental device for measuring the characteristics of the optical lens joining device according to the present invention. The experimental apparatus of FIG. 3 includes a mirror 30 cut at 45 degrees, an optical lens joining apparatus 300 of the present invention or the related art, and a spot measuring apparatus 32.

Next, the operation of this experimental apparatus will be described. The laser light from the light source is mirror 30 cut at 45 degrees.
Scanning width -15mm ~ + 15m by rotating
scanned with m. The scanned laser light forms an image on the image forming surface 33, and the spot diameter on the image forming surface 33 is measured. The measurement is performed for both the half width of the beam spot and 1 / e ² .

FIG. 4 shows an explanatory view of the measured laser light. FIG. 4 (A) shows a laser intensity distribution diagram measured by the experimental apparatus of FIG. Further, FIG. 4B shows a characteristic diagram of the spot shape measured by the experimental apparatus of FIG. Generally, in a laser application device such as a laser scanner, the width of 1 / e ² in FIG. 4A is particularly related to the performance of the optical lens joining device.

FIG. 5 shows a characteristic diagram of the spot diameter by the present invention and the conventional optical lens joining device. Here, the laser scans only in the X direction. FIG. 5A shows the spot diameter in the X direction, and FIG. 5B shows the spot diameter in the Y direction. In each of FIG. 5 (A) and (B),
The plot lines are those of the conventional optical lens joining device, the plot lines are those of the optical lens joining device of the first embodiment using the separate shrink fitter according to the present invention, and the plot lines are the The optical lens joining device of the second embodiment using the integral shrink fitter according to the invention is shown respectively.

As shown in the figure, the conventional average spot diameter is 1
It is 3.4 μm, and it can be seen that the spot diameter is extremely widened with respect to the theoretical value of 6.6 μm with increasing distance from the central portion. On the other hand, in the case of the optical lens joining device according to the first embodiment using the separated shrink fitter according to the present invention, the average spot diameter is 9.4 μm,
It can be seen that the spot diameter is clearly improved as it approaches both ends. However, the spot diameter still widens at both ends. It is considered that this is because the shrink fitter is individually manufactured according to the diameter of the lens, so that the influence of the shape error is remarkable. Further, in the case of the optical lens joining device according to the second embodiment using the integral shrink fitter according to the present invention, it is better than the one using the separate shrink fitter as can be seen from the drawing. I understand.

From the results of the above experiments, the spot diameter is improved in the case of the optical lens joining device of the second embodiment, which is manufactured as an integrated type, as compared with the case where the shrink fitter is separately manufactured. You can see that it will be even more.
By integrating the shrink fitter, it is possible not only to improve the eccentricity of the lenses, but also to facilitate disassembly and reassembly when the lens groups are joined in the lens barrel. Furthermore, by changing the dimension of one of the spacers in the axial direction, the distance between the lens 23 and the lens 24 is 0.2 m from the design value.
By separating them by m, it is possible to narrow down to 6.9 μm.

[0022]

According to the present invention, in order to minimize the eccentricity of the lens, an optical lens joining device by shrink fit using a shrink fitter (joining member) is provided as an example, and it is possible to improve the performance of laser application devices and the like. It is possible to achieve higher resolution and higher accuracy.

According to the present invention, it is possible to provide an optical lens joining device capable of joining lenses by an interference fit by using a joining member made of a polymer material in which the lens group and the lens barrel are integrated. According to the present invention, the interference fit can be applied whether the lens groups in the lens barrel have different diameters or the same diameter, or a plurality or a single lens group. Further, according to the present invention, the axial distance between the lenses can be accurately positioned at the time of inserting the lens group into the cemented member, and then the lens can be incorporated in the lens barrel. Further, according to the present invention, the eccentricity of the lens can be improved, and disassembly and reassembly can be easily performed.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of a first embodiment of an optical lens joining device according to the present invention.

FIG. 2 is a vertical sectional view of a second embodiment of an optical lens joining device according to the present invention.

FIG. 3 is a configuration diagram of an experimental device for measuring the characteristics of the optical lens joining device according to the present invention.

FIG. 4 is an explanatory diagram of measured laser light.

FIG. 5 is a characteristic diagram of a spot diameter according to the present invention and the conventional optical lens joining device.

FIG. 6 is a vertical cross-sectional view of a scanning lens system according to a conventional technique.

[Explanation of symbols]

21-26 lenses 200 lens barrel 210 Integrated shrink fitter 230 joining surface

Claims (7)

(57) [Claims] 1. A first optical lens having a first diameter, a second optical lens having a diameter different from the diameter of the first optical lens, and the first and second optical lenses inside. a lens barrel for housing, are formed in a large polymeric material than the thermal expansion coefficient of the lens barrel, and the junction portion of different inner diameters corresponding to the diameters of the first and second optical lens, said first and second 2 optical lenses
An optical lens joining device having a joining surface for joining with a joining width narrower than the width of the outer periphery thereof, and comprising a joining member for joining the lens barrel and the first and second optical lenses. 2. A first optical lens having a first diameter, a second optical lens having a diameter different from the diameter of the first optical lens, and the first and second optical lenses inside. A lens barrel to be housed, a joint portion formed of a polymer material having a thermal expansion coefficient larger than that of the lens barrel, and having different inner diameters corresponding to the diameters of the first and second optical lenses, and a string-shaped member. The joint
For fixing the first and second optical lenses in the material
An optical lens joining device having a groove in a circumferential direction and provided with a joining member for joining the lens barrel and the first and second optical lenses. 3. A first optical lens having a first diameter, a second optical lens having a diameter different from the diameter of the first optical lens, and the first and second optical lenses inside. A lens barrel to be housed, a joint portion formed of a polymer material having a thermal expansion coefficient larger than that of the lens barrel, and having different inner diameters corresponding to the diameters of the first and second optical lenses ; Half over thickness
A slit is provided in the radial direction, and the lens barrel and the first and second
And an optical lens joining device for joining the optical lens. Wherein said first and second optical lenses, optical lens bonding apparatus according to claim 1 or 2 or 3, characterized in that a plurality of lens shape conformal and / or profiles. 5. The joining member passes through a string-shaped member and is connected to the front.
Fix the first and second optical lenses in the joining member.
A groove is provided in the circumferential direction for the purpose of :
1. The optical lens joining device according to 1 or 3 . Wherein said bonding member includes an optical lens bonding apparatus according to claim 1 or 2, further comprising a slit in a radial direction across the thickness of the part or the whole. Wherein said joint member, according to claim 2 or 3, characterized in that it comprises a bonding surface for bonding said first and second optical lens with a narrow bonding width than the width of the outer peripheral Optical lens joining device.