JPS59157603A - Holding structure of lens - Google Patents

Abstract

PURPOSE:To incorporate a lens directly without using any other parts, etc., and to facilitate the incorporating operation and improve its accuracy by molding integrally collar parts, etc., on outer circumferences of molded lens bodies and reinforcing them by ion exchange, etc. CONSTITUTION:The molded lenses 1 and 2 are provided with the collar parts 1a and 2a on the outer circumferences of the main bodies; those collar parts require size precision and physical strength as abutting parts 1b and 2b and detaining parts 1c and 2c forming tapered surfaces 1d and 2d are the same. Glass surfaces at respective positions of the optical glass of each lens is made different in composition to increase the strength. For this purpose, a reinforcing treatment by ion exchange is carried out. Namely, lithium molten salt is brought into contact above the dislocation temperature of the glass materials of the molded lenses 1 and 2 and below the softening point to substitute glass composition components with Li.

Description

Detailed Description of the Invention The present invention relates to a lens holding structure for fixing a molded lens made of plastic material or optical glass material to a lens holding tube in a lens barrel. Lens materials that can be applied to lenses for cameras, microscopes, measuring instruments, and various optical instruments have been developed.

Further, molding techniques are being developed to use the above-mentioned materials for the above-mentioned purposes.

In the plastic material and optical glass material described above, a locking portion for locking the lens to a holding member can be formed on the outer periphery of the effective surface that performs optical functions such as refraction and reflection of the lens.

Fig. 1a and Fig. 1 show the shape of the molded lens 2 applied to the lens holding structure of the present invention.
The area centered at 0 and having predetermined diameters D1 and D2 is called an effective surface for the optical action, and the outer periphery thereof is called an ineffective surface.

la.2a is a flange integrally molded with the lens body l.2 on the outer periphery of the non-effective surface of the molded lens, and end surfaces 1b and 2b of the flange in the optical axis direction are abutting parts. . The abutting portions ib and 2b serve to determine the reference position for fixing the lenst 2 in the direction along the optical axis within the lens barrel when the lenst 2 is assembled into a lens holding member described later.
is a locking portion provided on the outer periphery of the molded lens 2. The locking portion is provided on the outer periphery of the flange portions la and 2a, and tapered surfaces 1d and 2d are provided on the negative side.

FIGS. 2a and 2b show an example of the lens holding member of the present invention, and the lens holding member 4 includes a fitting portion 4a that fits with the outer circumferential surface of the flange portion ia/2a of the molded lens, and the fitting portion The inner side of the lens 4a has an abutting portion 4b against which the abutting portions 1b and 2b of the molded lens 2 abut. Reference numeral 4C indicates a locking piece extending in the direction along the optical axis from the vertical end surface of the lens holding member 4 in the optical axis direction, and the tip of the locking piece 4c is pushed outward as shown by the dotted line in FIG. As shown in Figure 2a, it has a thinner wall that spreads out (td).
.

As shown in FIG. 2a, the locking pieces 4C may not be provided all the way around the optical axis from the end surface of the fitting portion 4a of the lens holding member 4, but may be provided at approximately three equal intervals. , or may be provided all around the circumference.

Figure 3 shows the molded lens 1 shown in Figure 1a in Figures 2a-b.
A cross-sectional view of the lens held by the lens holding member shown in lc is shown.

FIG. 3 shows an example in which the molded lens l is fixed to the lens holding member 4 via the lens 11.

First, the lens! , abuts the outer circumferential end of the molded lens 1 against the abutting portion 4b of the lens holding member 4, and then
The abutting portion 1b of is abutted on the outer periphery of the lens/I. Next, the locking piece 4c of the lens holding member 4 is
Push it outward as shown by the dotted line in the figure. Alternatively, when the molded lens l is press-fitted into the inner peripheral fitting surface of the fitting part 4a of the lens holding member, the locking piece 4c moves along the taper of the locking part IC of the molded lens l as indicated by the dotted line in FIG. As the width is expanded outwardly, the locking portion 1c of the molded lens fits into the hollow portion 4d of the locking piece. As a result, the lens/1 and the molded lens 1 are held by the lens holding member 4.

In the above configuration, the dimension A in the direction along the optical axis from the abutting portion of the lens holding member 417 to the position where the locking piece 4C locks with the locking portion 1c of the molded lens is lens l! ,
and the dimension B from the tip of the abutting portion of the molded lens l to the locking end surface of the locking portion is set to be s smaller than the sum of B, 1,000. This dimension A is
It is selected appropriately depending on the material of the lens holding member 4, the length and thickness of the locking piece 4C, etc.

FIG. 4 shows an example in which the present invention is applied to a lens barrel. In the embodiment shown in FIG. 4, the front group lenses l, .l, .I! 1 and rear group lens L! 4・l,・l! 6
is held.

In FIG. 4, reference numeral 8 denotes a fixed tube, and 10 denotes a double helicoid tube having helicoids on the outer and inner circumferences, which is disposed between the fixed tube 8 and the lens holding member 6. 12 is a distance ring fixed to the double helicoid by screws 14; 16 is the aperture setting ring. Said fixed tube 8・double helicoid tube 1o・
The configurations and functions of the distance ring 12, aperture setting ring L6, etc. are well known, so their explanation will be omitted.

The lens holding member 6 includes a cylinder main body part 6a provided with a helicoid that is helicoidally coupled to the double helical coid cylinder 10, and a cylinder main body part 6aVc that is continuous with the front lens group right to l.
The first lens holding cylinder part 6b that holds the rear lens l! ;~l, has a second lens holding cylinder part 6c for holding. Each lens l in Figure 4! ,~l! Among 6, 1!1 of the front group lens indicates the molded lens shown in Fig. 1 alC,
/S of the rear lens group indicates the molded lens 2 shown in FIG. The first and second lens holding cylinder parts 6b and 6c are the second lens holding cylinder parts 6b and 6c.
It has the same configuration as the lens holding member 4 shown in FIGS. a-b.

In the above-described embodiment, the notched portion 4d of the locking piece of the lens holding member 4 may be formed into a groove of any type.・Also, in the embodiments shown in FIGS. 3 and 4, the molded lens l or 2 may be replaced with another lens l! Although the molded lens 2 is abutted against the abutting part of the lens holding member through I/l<, the optical glass material abutting the lens holding member is directly molded by pressure molding, etc., without using conventional polishing process. The lens can be directly assembled into the lens holding member without using tightening screws, tightening rings, etc., making the kite-loading work easier and more accurate. .

Next, the molded lens 2 shown in FIGS. 1a-b and applied to the present invention will be described.

As described above, the molded lens is provided with a flange portion la and 2a on the outer periphery of the lens body. The flange is formed so as to extend in a ring shape around the outer periphery of the non-effective surface of the lens body, and one end of the flange abuts against the abutting part of the lens holding member 4 of the molded lens 2, and the lens-holding member Out of 4. On the outer periphery of the fitting portion that fits with the circumferential fitting surface, locking portions 1c and 2c are provided with tapered surfaces in a direction intersecting the optical axis. A molding piece 2 having such a shape can be processed using a molding die 20 shown in FIG. 5 as a method of press-molding a molten plastic material or an optical glass material. In FIG. 5, 20a and 20b indicate the lower die for award 20c and the upper die for molding.

For example, the molded lens 1 is molded using the molding ff120 in FIG.
When making an optical glass material from an optical glass material, it is possible to use the apparatus shown in the specifications of Patent Application Publication No. 38126 of 1978, U.S. Patent No. 416896X, U.S. Patent No. 4139677, etc. can.

As mentioned above, the molded lens 2 is provided with flanges 1a and 2a on the outer periphery of the lens body, and the flanges 1a and 2a are required to have dimensional accuracy and physical strength as disaster protection parts 1b and 2b. Further, the locking portions 1C and 2c formed with the tapers 11a and 2d are also required to have dimensional accuracy and physical strength.

Therefore, the molded lenst 2 according to the present invention has a non-effective diameter of the molded lenst 2 (Fig.
), especially the parts that abut, fit, and lock with the lens holding member 7 (abutting parts 1b and 2b, fitting parts, and locking parts IC and 2C) are chemically strengthened. The strength of the optical glass of the molded lens 2 is increased by changing the composition of the glass surface at each of the locations.

As a method of strengthening each of the above-mentioned parts, a strengthening treatment using ion exchange is performed. The glass material of the molded lens 2 is brought into contact with a molten salt of lithium (Li) in a temperature range above the transition temperature and below the softening point to cause Li substitution with the glass composition.

Further, after the molded lens 2 is molded into the shape shown in FIGS. 1a-b using the mold shown in FIG. 5, ion exchange at low temperature is performed as a method of strengthening the above-mentioned parts.

That is, ion deposition is performed by bringing the molded lens 2 into contact with a molten salt of an alkali having a larger ionic radius than the alkali contained in the lens at a temperature not exceeding the transition temperature.

[Brief explanation of the drawing]

FIGS. 1a-b are cross-sectional views of a molded lens used in the present invention. FIGS. 2a-b are a perspective view and a cross-sectional view of the lens holding member. FIG. 3 is an axial cross-sectional view when the lens is assembled into the lens holding member. FIG. 4 is an axial sectional view of another embodiment of the invention. FIG. 5 is a sectional view of a mold for molding the molded lens 2. l・2...Molded lens 4...Lens holding member 40μ

Claims (3)

[Claims] (1) In a holding structure for a molded lens in which the lens is molded from a plastic material or an optical glass material, a lens holding member that holds the molded lens is placed directly or indirectly on the outer periphery of the non-effective surface of the molded lens. A locking part having a tapered part inclined in a direction intersecting the optical axis is provided on the abutting part and the outer periphery, and the lens holding member has a fitting part that fits with the molded lens, and a locking part having a tapered part inclined in a direction intersecting the optical axis. The direction of the optical axis between the abutting part of the molded lens and the fitting part, which abuts directly or indirectly through another lens to determine the fixed reference position on the optical axis of the molded lens, is 3°. The molded lens has a thin locking piece that extends in the direction along the optical axis from the opposite end face and is provided with a slotted part, and the molded lens is expanded by pushing the locking piece of the lens holding member along the tapered part. The lens holding structure is characterized in that the molded lens is held on the lens holding member by engaging the locking part of the molded lens with the comb part and locking the locking piece and the locking part. . (2) The notched portion of the locking piece has a penetrating lens holding structure. (3) In order to hold the lens on the lens holding member, a flange that fits or locks with the lens holding member is molded integrally with the lens body on the outer circumference of the effective diameter of the lens, and the flange is attached to the lens. A lens holding structure characterized by using a molded lens that is partially reinforced with respect to the main body.