JPS5969707A - Method and device for manufacturing lens system - Google Patents

Abstract

PURPOSE:To eliminate the movement of a lens after assembly and the performance drop due to a clearance by filling a range of an effective diameter of an air space part between each lens with resin which is hardened by a light source of a specified wavelength area, and coupling each lens as one body. CONSTITUTION:A lens L1 is placed closely onto the bell upper edge of a reference base 6, light from a laser oscillator 8 is detected by a detector 13, the lens L1 is held at a prescribed position by adjusting the circumferential part of the lens L1 by an adjusting screw 15 of a casting frame 5, and subsequently, a transparent resin 16 is injected into an enclosed space between the reference base 6 and the lens L1. In the same way, lenses L2, L3 are placed, and the resin 16 is injected. Subsequently, when a beam of a specified wavelength range is irradiated, the resin of only the part to which the beam is irradiated is hardened, and the lenses L1, L2 and L3 are coupled as one body. Accordingly, as for a lens system after assembly, no movement of a lens for performance drop due to a clearance is caused, and a lens system which is free from time ageing and has high accuracy can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a lens system composed of a plurality of lenses, a method for manufacturing the same, and an apparatus for manufacturing the same.

The lens design of an optical system determines the lens shape spatially,
The arrangement of the lenses is determined, and the design of the lens barrel that holds the lenses constituting the lens system in the designed arrangement is done after that. A single lens system is completed only when the two are combined, but when assembling the lens barrel conventionally, lens quality has deteriorated due to clearance and other factors. Furthermore, even if eccentricity was measured and assembled at the time of assembly, adjustment was difficult and time consuming due to constraints on the size of the lens barrel. Even after assembly, the lens sometimes moved within the lens barrel, significantly reducing lens performance.

The present invention eliminates the above-mentioned drawbacks of conventional lens systems due to the conventional construction and assembly method.Each lens is accurately assembled in a spatial arrangement that plays a role, and the assembly is performed by subsequent lens movement and clearance. It is an object of the present invention to provide a lens system that does not cause performance deterioration, and a method and apparatus for manufacturing the same.

Hereinafter, the present invention will be explained in detail based on embodiments shown in the drawings.

FIG. 1 is a diagram showing the configuration of an embodiment of a lens system according to the present invention. The lens system of this example has three lenses t, 1
, t,2, and t,3, at least the range of the effective diameter of the portion corresponding to the air gap between each lens is filled with transparent resin 16. This resin is cured in only the required portions by the manufacturing method according to the present invention, which will be described later, to integrally bond the lens system. A resin is used that hardens by irradiating the area with light. It goes without saying that in this lens design, the refractive index of the air gap is calculated as the refractive index of the above-mentioned resin. Figures 2 and 3 show an example of a jig for manufacturing a lens system according to the present invention. be. A reference stand 6 having a bell shape with an upwardly opened mouth is mounted on the base 7. The aperture of this bell is sized so that the lens Ll of the lens system to be manufactured on it can be supported at the periphery.
Lens Ll'f: The upper edge of the bell is finished completely horizontally and smoothly so that when placed on this, the upper edge of the bell and the lower surface of the lens Ll are in close contact with each other without any gaps. A cylindrical resin casting frame 5 is removably provided on the reference stand 6. Its inner diameter and height are large enough to accommodate the lens system to be manufactured, and it is positioned by fitting into a step provided on the reference stand 6 concentrically with the bell. 1. In this state, it is integrated with the reference stand 6 to form a casting space. In the casting frame 5, with the reference lens Ll placed on the bell of the reference stand 6, three lenses are placed on the circumference at positions corresponding to the end faces of each lens Ll, L2, L3. Adjustment screw 1
5 is provided through the tapped hole so that its position can be adjusted.

Further, the screws 14a that respectively support the split bell rings 14 that support the peripheral parts of the lower surfaces of the second lens L2 and the third lens L3 in predetermined positions with high accuracy pass through screw holes provided in the casting frame 5. It is provided so that its position can be adjusted.

When the screw 14 is fully tightened against the casting frame 5, the split pellet ring is in a position suitable for supporting lenses L2 and L3 around the periphery, and the screw 14a is moved radially outward. In this state, a lens placed below the split Pell ring 14 can freely pass through the inside of the split Pell ring 14.

A laser oscillator 8 is provided below the substrate 7, and the laser light emitted from it passes through a beam expander 9 and is reflected by a reflecting mirror 1.
1, passes through the axis of the reference stand 6, and passes through the half mirror 3 installed on the top of the jig 5.6 at an angle of 45° with respect to the axis. It is detected by a detector 13 provided on the axis.

On the side of the half mirror 3, there is a light source l that emits light in a specific wavelength range, for example, near ultraviolet range, for curing the resin.
and a lens 2 that converts the light beam emitted from this into a parallel light beam.
is provided. An aperture 4 is provided between the mirror 3 and the casting device, and circuit breakers 12 are provided between the laser oscillator 8 and the beam extractor 9 and directly below the hole 7a of the base 7, respectively. A method of manufacturing a lens system using the apparatus constructed as described above will be described below.

The lens L1 is placed on the bell of the reference stand 6 with the resin casting frame 5 removed. Thereafter, the casting frame 5 is fitted into the stepped portion of the reference stand 6 and set, and the 3-point adjustment is made with the position adjustment screw 15 with respect to the lens Ll, and the circuit breaker 1 is held.
0 and 12 are opened, a laser beam is emitted from the laser oscillator 8, passed through the lens, and detected by the detector 13.
Adjust and hold in position. Next, transparent resin 16'f, which is cured by irradiation with light in a specific wavelength band (near ultraviolet region in this case), is poured into the casting frame in liquid form.

Since the lower surface of the second lens L2 and the edge of the bell of the reference stand 6 are in a sealed state, liquid resin does not enter the inside of the bell. Next, the split bell ring 14 for the second lens L2 is set with the screw 14a at a predetermined position that supports the lens L2, and the second lens L2 is placed thereon. In this case, if the lower surface of the lens is concave as shown in the figure, consideration must be taken such as inserting it into the liquid resin while tilting it so that no air remains in the concave part, and then placing it horizontally on the bell ring. . As in the case of the rear cylinder lens Ll, the eccentricity is adjusted and maintained using the adjustment screw 15. Regarding the third lens L3, the divided Pell ring 14 is similarly moved and placed in a predetermined position, and the eccentricity is adjusted using the screw 15. At this time, it is necessary to determine in advance the amount of resin to be injected so that the effective diameter of the upper surface of the third lens L3 is not immersed in the liquid resin.

Alternatively, a bell larger than the effective diameter may be brought into contact with the upper surface of the lens. Note that when the lower surfaces of the second and third lenses are convex, the resin may be injected after setting and adjusting the lenses.

As described above, the eccentricity of each lens is adjusted and positioned at predetermined intervals. Then, the circuit breaker, IO, 12 is closed to block the laser light, and near-ultraviolet light is emitted from the light source I.
The light beam is turned into a parallel light beam by the lens 2, reflected by the half mirror 3, and then passed through the lenses L3, L2. The light enters LL so that the optical axis is parallel to the main axis of the lens system. At this time, the opening degree of the diaphragm 4 is set so that the luminous flux has a predetermined effective diameter at the lenses Ll, L2, and L3. Only the portion of the resin 16 in the casting frame 5 that is hit by the light is cured, and the other portions are not cured and are maintained in a liquid state. In this way, the lens Ll,
Since L2 and L3 are joined together through a hardened resin, loosen the adjustment screw 15 and turn the screw 14a to shift the split Pell ring 14 outward from the range of the lens, and then adjust the end face of the lens L3 by appropriate means. By grasping and pulling up the lens system, the lens system that has been joined together can be taken out from the liquid resin, and in this way, one lens system shown in FIG. 1 can be obtained. Uncured resin adhering to the lens of this lens system and the surface of the cured resin can be removed by cleaning. Further, the uncured resin remaining in the casting frame 5 is recovered by appropriate means.

As described above, a lens system in which the constituent lenses are arranged and fixed as designed can be obtained, so that lens performance extremely close to the designed value can be obtained.

This lens system is a solid body that is integrated into one unit, so it can not only be used as is, but it can also be inserted into a lens barrel and fixed in the lens barrel. It can also be used in In that case, the above lens system and lens barrel are fixed integrally, so there is no performance deterioration due to lens movement or clearance after assembly.
A highly accurate lens system that does not change over time can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the configuration of an embodiment of a lens system according to the present invention, FIG. 2 is a longitudinal cross-sectional view showing an embodiment of a lens system manufacturing apparatus according to the present invention, and FIG. 3 is a section II-II in FIG.
FIG. 1-4...Resin curing specific wavelength light irradiation means 5...Resin casting frame 6...Reference stands 8-13...Optical axis eccentricity reading means 14, 148...Lens spacing adjustment means 15... - Lens decentering adjustment means 16...Resin Ll that hardens with light in a specific wavelength range,
L2, L3... Lens agent Patent attorney Takehisa Ito

Claims (3)

[Claims] (1) In a lens system composed of multiple lenses, at least the range of the effective diameter of the portion corresponding to the air gap between each lens is filled with a resin that hardens with light in a specific wavelength range, and A lens system characterized by combining each lens into one. (2) Consisting of multiple lenses, at least the range of the effective diameter of the part corresponding to the air gap between each lens is filled with a resin that hardens with light in a specific wavelength range, and each lens is joined together via this resin. In the method for manufacturing a lens system, the eccentricity and mutual spacing of each lens are adjusted, and the gap between each lens is filled with the liquid resin so that no air bubbles remain, and then the wavelength of the resin is cured. A lens system characterized in that the lens system is illuminated with a light beam of a region to harden the resin within at least an effective diameter range, and the lens system is taken out as a lens system integrally joined by the hardened resin. Production method. (3) Consisting of multiple lenses, at least the effective diameter range of the portion corresponding to the air gap between each lens is filled with a resin that hardens with light in a specific wavelength range, and each lens is integrated via a tube. A lens system manufacturing apparatus coupled to a lens system includes: a reference stand having a bell-shaped portion that hermetically supports a reference lens of the lens system at its periphery; A resin casting frame capable of accommodating the lens system, means for adjusting eccentricity and lens spacing of each lens one by one, optical axis eccentricity reading means, and a light beam in a specific wavelength range for curing the resin described above to be applied to the lens. 1. A lens system manufacturing apparatus, comprising: an irradiation device that illuminates the system parallel to its optical axis.