JPS61105519A - Lens holding device and lens centering device using it - Google Patents

Abstract

PURPOSE:To center even a lens having a relatively large curvature and fix and hold it easily in this state by forming a slope on the outside peripheral surface of the lens and using the cooperative action of this slope and a member which is brought into contact with this slope to press the lens. CONSTITUTION:When a retaining ring 11 is screwed in, the inside peripheral end part in the screwing-in direction of the retaining ring 11 is brought into contact with a slope 13. When the retaining ring 11 is screwed in furthermore, a lens 9 is centered by the principle of the bell clamp system. Since contacting parts between the lens 9 and a lens holding step part 14 and between the lens 9 and the retaining ring 11 are so inclined that angles theta2 and theta3 of friction (angles made between common tangents on respective contacting faces between the lens 9 and the lens holding step part 14 and between the lens 9 and the retaining ring 11 and planes orthogonal to an optical axis l), the contact resistance (the force of friction) is reduced very much, and consequently, each contacting part is moved light, and the centering operation is performed smoothly.

Description

TECHNICAL FIELD The present invention relates to a lens holding device and a lens centering method using the holding device.

Prior art As a device for holding a lens in a lens frame, the first type of device is generally used.
A device as shown in the figure is known.

That is, this lens holding device 1 has a stepped portion 4 for positioning the lens 3 formed on the inner circumferential surface of a cylindrical lens frame 2, and this stepped portion supports the outer circumferential portion of one side of the lens 3. , the lens can be pressed and fixed via a lens holding ring 7 having a male threaded part 6 which is screwed into a female threaded part 5 screwed onto the inner circumferential surface of the lens frame 2.

According to the above configuration, the lens 3 can be held with a desired holding force by moving the presser ring 7 forward and backward in the axial direction.

Furthermore, it is well known that by using the lens holding device 1, the optical axis of the lens 3 can be aligned with the axis of the lens frame 2 based on a principle called the so-called bell clamp method.

However, the conventional lens holding device 1 and the lens centering method using the device have the following problems.

That is, in the above lens centering method, when the lens 3 is pressed through the presser ring 7, the lens 3 is decentered in the direction in which it is aligned at the contact portion with the stepped portion 4 and the contact portion with the presser ring 7. Since the lens 3 is centered by moving by the same amount, the contact resistance at the contact portion between the lens 3 and the stepped portion 4 and/or the contact resistance at the contact portion between the lens 3 and the presser ring 7 is large. sometimes.

There was a problem in that the lens 3 could not be moved smoothly, making so-called centering of the lens 3 difficult or impossible. Therefore, if (=, friction angle (angle between the common tangent on the respective contact surfaces of the lens 3 and the stepped portion 4 or the lens 3 and the presser ring T and the plane orthogonal to the optical axis) θ1 is small, in other words, When the radius of curvature of lens 3 is large,
Contact resistance (!l! friction force) between the lens 3 and each contact portion when centering and fixing the lens 3 while pressing it through the holding ring 7
As a result, the movement of the lens 3 becomes heavy, making it extremely difficult to perform centering using the bell clamp method, making accurate centering impossible.

OBJECT OF THE INVENTION The present invention has been made in view of the problems of the prior art described above, and its purpose is to easily and accurately adjust the centering of lenses even when the radius of curvature is large, and to place lenses within a lens frame. It is an object of the present invention to provide a lens holding device capable of fixedly holding a lens and a method for centering a lens using the device.

Summary of the Invention The present invention provides a lens having an inclined surface formed on the entire circumference or continuous portion of the outer peripheral surface, a lens frame that houses the lens, and a lens that is in contact with the inclined surface of the lens that is housed in the Akatsuki frame. A lens holding device comprising: a lens holding portion for holding the lens; and a holding member screwed onto the lens frame so as to be movable in an axial direction and holding the lens in cooperation with the lens holding portion; It is therefore an object of the present invention to provide a method for centering a lens using the apparatus.

Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to FIG. 2 and subsequent drawings.

FIG. 2 shows a first embodiment of a lens holding device 8 according to the present invention. As shown in the figure, the lens holding device 8 is composed of a lens 9 as an object to be held, a lens frame 10 for storing and holding the lens 9, a presser ring 11 for pressing and holding the lens 9 in the lens frame 10, etc. It is.

The lens 9 is a lens in which both surfaces, that is, an object side surface (lower surface) 9a and an image side surface (upper surface) 9b, are formed with a relatively large curvature, and the outer edges of each surface 9a and 9b are appropriately shaped. The inclined surfaces 12 and 13 are respectively formed.

Each of the inclined surfaces 12 and 13 is formed so that the lens diameter gradually increases toward the central portion (=) of the lens 9, i.e.,
The friction angle θ between the lens holding step 14 of the frame 10 and the lens 9 and the friction angle θ between the lens 9 and the holding ring 11, which will be described later, are the friction angles before the inclined surfaces 12 and 13 are formed. It has a sloped configuration so that it is larger than the actual size. In addition, each inclined surface 12
, 13 are designed so as not to affect the effective luminous flux of the lens 8.

The lens frame 10 is formed into a cylindrical shape, and an inclined surface 1 formed on the object side surface 9a of the lens 9 accommodated therein is formed on the inner peripheral surface of the lens frame 10.
A lens C (a stepped portion 14 is formed for holding and positioning the lens 9 by contacting with the lens 9, and a female screw 15 is screwed on the inner circumferential surface of the image side surface 9b of the lens 9. This female thread 15 has a male thread 1 that screws into the female thread 15.
A retainer ring 11 having a ring 6 screwed onto its outer peripheral surface is screwed so as to be freely movable forward and backward in the axial direction of the lens frame 2. An optical path through hole 11 is formed through the axis of the holding member 11, and the diameter of this through hole 17 is set to match the effective luminous flux diameter of the lens 8. The screw-in direction end of the inner peripheral surface of the presser ring 11 formed by the through hole 17 is
The lens 9 is configured to freely come into contact with an inclined surface 13 formed on the image-side surface 9b of the lens 9. Note that the diameter dimension d of the inner peripheral surface of the lens frame 10 formed by the lens holding stepped portion 14 of the lens frame 10 is
It is also shaped so that the effective luminous flux diameter can be maintained.

A method for centering the lens 8 using the lens holding device 8 having the above configuration will be described. First, the lens 9 is inserted into the lens frame 10. At this time, the object side surface 9a of the lens 9
Insert it so that it faces down as shown in the figure. Then, the inclined surface 12 formed on the object-side surface 9a of the lens 9 aligns with the lens frame 1.
The lens 9 comes into contact with the lens holding step 14 of No. 0, and the lens 9 is positioned.

Thereafter, the presser ring 11 is screwed into the lens frame 10 via the screws 16 and 15. When the presser ring 11 is screwed in, the end of the inner circumferential surface of the presser ring 11 in the screwing direction comes into contact with the inclined surface 13 of the lens 9 . After the presser ring 11 and the inclined surface 13 come into contact, the presser ring 11 is screwed in. This screwing operation causes the lens B to be pressed down with a predetermined force, but the presser ring 11 is screwed into the lens so that this pressing force is within a range that does not change the optical characteristics of the lens 9. 8 in the optical axis direction.

Next, the effects of the holding device 8 and the lens centering method using the holding device 8 will be explained.

When the lens 9 is dropped into the lens frame 10, the optical axis of the lens e and the axis of the lens frame 10 often do not coincide.

Here, as the presser ring 11 is screwed in, the inner circumferential end of the presser ring 11 in the screwing direction comes into contact with the inclined surface 13. Presser ring 11
When the lens 9 is screwed in further, the lens 9 tends to be centered by the principle of the so-called Pell clamp method. Here, the mutual contact portions of the lens 9 and the lens holding step 14 and the lens 9 and the presser ring 11 have a friction angle of M (the contact portions of the lens 9 and the lens holding step 14 and the lens 9 and the presser ring 11, respectively). Since the surface (the angle between the common tangent at = and the plane perpendicular to the optical axis ρ) θ1.θ is large (=inclined), the contact resistance (frictional force) is extremely small, and therefore each contact As a result, even in the case of a lens having a lens surface with a large radius of curvature, the lens 9 can be accommodated and held within the lens frame 10. Lens 9 with high precision
The optical axis of the lens frame 10 can be made to coincide with the axis of the lens frame 10.

In FIG. 2, the stepped portion 14 that holds the lens 9 by coming into contact with the inclined surface 12 of the lens 9 is integrally provided, but the stepped portion 14 is constructed separately, and the mirror It may be configured to be fixed to the inner peripheral surface of the frame 10.

FIG. 3 shows a second embodiment of the invention. The feature of this embodiment is that the lens holding step portion 14 in the first embodiment is constructed as a separate body, and the second retaining ring 18 constructed as a separate body is connected to a male screw portion 19 on the retaining ring 18 side. Female thread part 20 on the side of the lens frame 10
The lens frame 10 has two screws attached to each other through the lens frame 10.The rest of the structure is the same as that of the first embodiment, so the same members are given the same reference numerals and the explanation thereof will be omitted. Note that although the figure illustrates a double-sided concave lens 9, the shape of the lens is of course not limited.

In the lens holding device 8 having the above structure, the lens 9 can be centered easily and with high precision using the same centering method as in the first embodiment.

FIG. 4 shows a third embodiment of the invention. As shown in the figure, a holding part 22 that locks and holds the aperture member 21 is integrally provided on the inner periphery of the lens frame 10 on one end side (lower end side in the figure). The diaphragm member 21 is provided with a diaphragm portion 21a, and the aperture diameter of the diaphragm portion 21a is shaped to be the effective luminous flux diameter of the object-side surface 24a of the cemented lens 24 cemented to the first lens 23. . Further, the other end of the diaphragm member 21 has an inner peripheral end formed on the inclined surface 25 formed in the cemented lens 24.
The cemented lens 24 is configured so as to be able to position and hold the cemented lens 24 by abutting against the lens. The cemented lens 24 is cemented to the first lens 23 having a small radius of curvature, and the object side surface 24a of the cemented lens 24 is formed to have a large medium diameter of curvature. The object-side surface 24a has a friction angle θ.

An inclined surface 25 is provided to increase the size.

A second lens 21 is housed above the first lens 23 via a spacing ring 26, and an inclined surface 28 is formed on the contact surface of the second lens 27 with the spacing ring 26. be. Note that the surface 27a of the second lens 27 on the joining side with the spacing ring 26 is formed with a large curvature, and the other side,
That is, the surface 27b on the contact side with the presser ring 11 has a small curvature.
It is shaped like this.

A lens centering method using the holding device 8 having the above configuration will be explained. First, the cemented lens 24 and the first lens 2
3 into the mirror frame 10. Next, the spacing ring 26 is stored, and the second lens 27 is further dropped. Finally, the holding ring 11 is screwed onto the lens frame 1G, and the holding ring 11 is screwed in the optical axis direction to attach each lens 24, 2.
3, press 27.

According to the above-mentioned centering method, each of the plurality of lenses 24, 23, 27 is operated in the same manner as in the first embodiment.

The centering of the lenses 24, 23, and 27 can be easily and precisely performed by holding the lenses 24, 23, and 27 in place.

In addition, in the above structure, the joint surface of the first lens 23 with the spacing ring 26 and the joint surface of the second lens 27 with the presser ring 11 may be formed into inclined surfaces to increase the friction angle. Of course.

FIG. 5 (1) shows a fourth embodiment of the present invention. As shown in the figure, the lens frame is composed of first and second lens frames 29 and 30, and both lens frames 29 and 30 are threaded. The two are connected to each other via 31 and 32.The inner peripheral surface of the first lens frame 29 (:
, step portions 36 and 37 are formed to hold the cemented lens 34 of the first lens 33 and the second lens 35, and the other surface of the cemented lens 34 is attached to the first lens frame 29. It is held by the inner circumferential end of a presser ring 38 that is screwed on. A stepped portion 40 for holding the aperture member 39 is formed at the end of the first lens frame 2g on the side connected to the second lens frame 30. Further, a stepped portion 42 for holding the third lens 41 is formed on the inner circumferential surface of the second lens frame 30.
is brought into contact with a lens surface 41a formed with a relatively small curvature. The cemented lens 34 and the second lens 3
The outer peripheral edges of each of the lenses 5 are provided with inclined surfaces 43, 44, 45, and 46 for increasing the friction angle, similar to the lenses of the first to third embodiments.

Further, the outer peripheral surface of the third lens 41 is also formed into an inclined surface 47. Note that 48 and 49 indicate adhesives.

A lens centering method using the holding device 8 having the above configuration will be explained. First lens 33. The method of centering the cemented lens 34 is based on the first embodiment.

Centering of the second lens 35 is performed as follows.

First, the second lens 35 is dropped onto the stepped portion 37.

Next, the second lens 35 around the stepped portion 37 and the first lens frame 2
An uncured adhesive 48 is filled between the inner circumferential surface of the adhesive 9 and the inner circumferential surface of the adhesive 9 . Next, the second lens 35 is pressed in the optical axis direction via a lens suppressing member (not shown) that comes into contact with the inclined surface 4B of the second lens 35, and the lens 3 of t42 is pressed by the bell clamp method.
Perform centering in step 5. After the adhesive 48 has hardened, the suppressing member is removed.

The method for centering the third lens 41 can be performed in a similar manner. After fixing the aperture member 39 (second, first,
The second lens frame 29 and 3G may be fixed respectively.

According to the lens holding device 8 and the lens centering method configured as described above, in addition to the effects of the first to third embodiments, the distance between each of the plurality of lenses 34, 35, and 41 is set small, making it compact. A holding device can be provided.

Incidentally, the inclined surface formed on the lens may be formed as an inclined surface 30 in only one direction in the entire outer circumferential surface of the lens 29 = the optical axis direction, as shown in FIG. 6, or, As shown in FIG. 7, an appropriate number of inclined surfaces 32 in the optical axis direction may be formed on the outer peripheral surface of the lens 29. Moreover, the inclined surface may be a flat surface or a curved surface.

Further, as shown in FIG. 8, between each inclined surface 32 of the lens 31 shown in FIG. 7, an inclined surface 33 whose inclination direction is opposite to that of each inclined surface 32 is formed in the optical axis direction. You may. The inclined surface 32 of the lens 31 shown in FIGS. 7 and 8
, 33 to center the lens 31,
It may be made of metal such as aluminum or brass that does not deform during compression, or plastic such as Teflon or epoxy resin, and its shape may be, for example, as shown in Fig. f49 (al, (b)).
, it may be configured as shown in FIG. , that is,
FIGS. 9(a) and 9(b) show the annular interval I
A protrusion 35 that engages with the inclined surfaces 32 and 33 of the lens 31 is provided on the inner peripheral surface of J34.
The figure shows protrusions 36, 3 that engage with the inclined surfaces 32, 33 of the lens 31 on the upper and lower surfaces of the annular interval 3II34.
7 are respectively provided in a protruding manner.

By using such a spacing ring 34, FIG.

A lens 31 having inclined surfaces 32 and 33 as shown in FIG. 8 can be fixedly held while adjusting its centering. Note that the portions of the projections 35 , 38 , 37 that engage the inclined surfaces 32 , 33 of the lens 31 preferably have sharp edges, but may be slightly chamfered.

Further, the lens to which the present invention can be applied is a glass lens.

It can be applied not only to plastic lenses but also to combinations or cemented lenses. or,
By adding a material such as Teflon resin, which has a coefficient of friction smaller than that of the lens material, outside the effective luminous flux diameter of the lens, and forming an inclined surface with this Teflon resin, the movement of the lens becomes lighter and centering becomes easier. This can be done more easily and with higher precision.

Effects of the Invention As described above, the present invention has an inclined surface formed on the outer peripheral surface of the lens, and the lens is centered by the cooperative action of this inclined surface and a member that comes into contact with the inclined surface and presses the lens. This is a lens holding device that is configured to be able to hold the lens securely and securely, and a lens centering method that uses this device, so even lenses with relatively large curvature can be easily fixed in a highly precisely centered state. It can be maintained and applied to automation.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional explanatory diagram of the prior art, and Figure 82 is the first diagram of the present invention.
Fig. 3 is a cross-sectional view showing an embodiment of i2 of the present invention. Figure A and Figure 4 are cross-sectional explanatory diagrams showing the third embodiment of the present invention, Figure 5 is cross-sectional explanatory diagrams showing the fourth embodiment of the present invention, Figures 21!6, Figures 7, and 8. Figure, No. 9
Figures (a), (b) and Fig. 10 are explanatory diagrams showing other embodiments of the main part of the present invention. 9.23, 27, 34, 35. 41・River・・Lens 10
．． 29.30・・・・・・・・・Mirror frame 11 ・
・・・・・・・・・・・・・・・・・・ Presser ring 14
．． 36, 37. 42... Lens holding step portion 12.
13, 25.2B, 43, 44.45, 46.47...
...Slope Figure 3 Figure 4 Figure 5 Figure 6 Figure 7

Claims (5)

[Claims] (1) A lens having an inclined surface formed on the entire circumference or a suitable part of the outer peripheral surface, a lens frame that houses the lens, and a lens that is in contact with the inclined surface of the lens that is housed in the lens frame. and a holding member that is screwed onto the lens frame so as to be movable in the axial direction and that cooperates with the lens holder to hold the lens. Device. (2) The lens holding device according to claim 1, wherein the inclined surface of the lens is formed in at least one direction. (3) The lens holding device according to claim 1 or 2, wherein the inclined surface of the lens is a flat surface. (4) The lens holding device according to claim 1 or 2, wherein the inclined surface of the lens is a curved surface. (5) A lens having an inclined surface formed on the entire circumference or an appropriate part of the outer peripheral surface is housed in a lens frame, and the inclined surface of the lens is held in contact with a lens holding part in the lens frame, and the lens is The lens is pressed in the optical axis direction via a member screwed into the frame so as to be movable in the axial direction, and the optical axis of the lens and the axis of the lens frame are connected via the lens holding portion and the member. A lens centering method characterized by aligning the lenses.