JPS6395409A - Lens moving device - Google Patents

Abstract

PURPOSE:To obtain a high-performance zoom lens which is not affected by any ghost flare, by performing anti-reflection treatment to a movement preventing member. CONSTITUTION:The convex guide member 10a provided at the bottom section of a fixed lens barrel 10 in an extended state has a rectangular cross section and anti-reflection treatment is performed to the upper surface 10f of the guide member 10a in such a way that numerous minute cuts are formed in the upper surface 10f, and so forth. Both sides of the guide member 10a are finished to mirror surfaces. The concave guide section 24a formed at the bottom section of a variator holding and moving frame 24 has a rectangular cross section and a width which is a little wider than that of the guide member 10a. The side faces of the guide section 24a facing each other are finished to have mirror surfaces and the guide member 10a is put in the guide section 24a in a state where the upper surface of the member 10a, to which the anti-reflection treatment is performed, is not brought into contact with the bottom section of the guide section 24a. Therefore, deterioration of lens performance due to the influences of a ghost flare produced by internal reflection can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a lens moving device for a zoom lens, an internal focusing lens, etc., which includes a lens that moves within a fixed lens barrel.

[Prior Art] A zoom lens, an internal focusing lens, or the like includes a lens that moves within a fixed lens barrel. The structure of a conventional zoom lens, which is an example of such a lens, will be explained based on FIG. 4. Although FIG. 3A shows a zoom lens to which one embodiment of the present invention is applied, since it is substantially the same as a conventional zoom lens except for the guide portions 22c and 24c of the guide member 1001, this FIG. 3A will also be referred to.

Generally, zooming with a zoom lens is performed by relatively moving two sets of lenses, a variator 40 and a compensator 42. Hereinafter, the movement 11 grooves of the variator 40 and the convencator 42 will be explained. The variator 40 is fixed to a variator holding/moving frame 42, and the pump sweater 42 is fixed to a convencator holding/moving frame 46. Each holding/moving frame 44, 46 has a cylindrical guide tube, '18. Guide balls 52, 54 (3rd A) fixed to
(See guide balls 32 and 34 in the figure), respectively. Further, the guide balls 52 and 54 are connected to the holding/moving frame 4
There is one hole drilled at 6.44.

Reference numeral 56 designates cam bins installed in the variator holding/moving frame 40 and 58 in the convencator holding/moving frame 42, respectively. These cam pins 56 and 58 are fitted into cam grooves of a cam cylinder fitted into a fixed lens barrel (see fixed lens barrel 10 and cam cylinder 12 in Fig. 3A), and are held and held in accordance with the rotation of the cam cylinder. The moving frames 44 and 46 are moved in the optical axis direction.

In the process of this holding/moving frame 44, 46 moving,
The optical axes of the variator 40 and the convencator 42 must always coincide with the optical axis of the entire optical system.

Therefore, the movement must be smooth and without vibration or twisting. For this purpose, conventionally, a steady rest ball 60 is provided in addition to the guide balls 52 and 54. The steady rest ball 60 is fixed to the bottom of the holding/moving frame 44.46, and the U-shaped grooves 44a and 46a formed at the bottom of each holding/moving frame 44.46 are fitted into the steady rest ball 60. Shaking is prevented.

The guide balls 52, 54 and steady rest balls 60 are mirror-finished to ensure smooth sliding, and are coated with a lubricant such as grease to fit the guide tubes 48, 50 and grooves 53.
54 to eliminate looseness and allow smooth sliding.

Since the conventional zoom lens has the above structure, each ball 52° 54, 6 guiding the holding/moving frame 44, 46
0 reflects light on its surface, causing ghost and flare.

In normal usage, the camera is used in an upright position, while a light source such as the sun or an electric light is outside the angle of view and located above the camera. Therefore, the light from the light source enters the lens from the front upper side of the camera, and after passing through the lens, it travels below the optical axis. Therefore, the light reflected by the steady rest ball 60 on the lower side of the fixed lens barrel is reflected by the guide ball 52.5 on the upper side.
more than the light reflected by 4.

Therefore, a device for preventing the reflection from the steady rest ball 52 is disclosed in Japanese Utility Model Application Laid-Open No. 58-16604@. That is, in this invention, a large number of notches are formed in the upper part of the steady rest ball to prevent reflection.

However, this idea has the problem that when assembling the lens, it takes time and effort to install and fix the steady rest ball with the notch facing upward.

[Problems to be Solved by the Invention] An object of the present invention is to provide a lens moving device that prevents the occurrence of ghost flare and is easy to assemble.

[Means for Solving the Problems] In order to achieve the above object, the present invention includes one or more guide balls provided in a fixed vL cylinder parallel to the optical axis, In the transfer device 8, in which a lens holding/moving frame is mounted so as to be movable in parallel, a concave or convex guide member is provided within the fixed lens barrel and extends parallel to the optical axis apart from the guide ball. The holding/moving frame is provided with a convex or concave guide portion that fits into or fits into the guide member and is slidable in the optical axis direction.

[Function] According to the present invention, since the anti-reflection treatment is applied to the steady rest member, a high-performance zoom lens free from the effects of ghost and flare can be provided.

In addition, since the fixed lens barrel and guide member are integrally molded,
It is possible to reduce the number of parts, the number of assembly steps, and costs.

[Examples] Examples of the present invention will be described below with reference to the accompanying drawings.

Fig. 1 is a perspective view showing the main parts of an embodiment of the present invention;
The figure is a perspective view showing a modified example of the steady rest member, Figure 3A is a vertical sectional view of a zoom lens to which the device of the present invention is applied, and Figure 3B
The figure is A-AI in Figure 3A! FIG. In FIG. 3A, 10 is a fixed lens barrel, and 12 is a cam barrel, which is rotatably fitted into the fixed lens barrel 10. In FIG. This cam cylinder 12 is connected to a zoom operation ring 14 and rotates together with it.

Variator 20, compensator 22, variator holding/moving frame 24, compensator holding/moving frame 26 guide 028.30, guide ball 32.34, cam bin 36
, 38 M4 construction, and the operation is substantially the same as the conventional example described above, so a detailed explanation will not be given.

Next, the features of the present invention will be explained. Reference numeral 10a denotes a convex guide member extending parallel to the optical axis at the bottom of the fixed lens barrel 10, and has a rectangular cross section.

The upper surface 10r of this guide member 10a is subjected to anti-reflection processing such as forming a large number of minute notches, and both sides thereof are subjected to mirror finishing.

22a is a concave guide portion formed at the bottom of the variator holding/moving frame 44, and has a rectangular cross section. The width of the guide portion 22a is very slightly wider than the width of the guide member 10a, and opposing side surfaces are formed into mirror surfaces to fit into the guide member 10a. However, the bottom portion is formed so as not to come into contact with the anti-reflection treated upper surface of the guide member 10a. A guide portion 24a is similarly formed on the compensator holding/moving frame 24, and is fitted into the guide member 10a.

FIG. 2 shows another embodiment of the guide member 10b1 and the guide portion 22.
b is shown. In this embodiment, contrary to the previous embodiment, the guide member 10b is formed in a concave shape on the fixed lens barrel 10, the guide portion 22b is formed in a convex shape, and the bottom surface 10b' of the guide member 10b is treated with anti-reflection processing. It is alms.

FIG. 3B shows still another embodiment of the guide member 10c and the guide portion 24c.

The guide members 20a, 20b, 20c can be integrated with the fixed lens barrel 10 and molded in one step, for example, by injection molding of synthetic resin. By molding in this manner, the required finishing accuracy of the guide members 20a, 20b, and 20c can be easily obtained, and by making minute notches on a predetermined surface of the mold to prevent reflection, This eliminates the need for anti-reflection treatment.

In addition, the influence of the draft angle in molding the guide member can be considered, but if this gradient is applied in the optical axis direction, the width of the front and rear ends of the guide member will change significantly, causing a gap between the guide part of the lens holding/moving frame and the guide member. This causes rattling. Therefore, if this handling slope is applied in the radial direction, and a corresponding slope is also provided in the guide portion of the holding/moving frame, wobbling will not occur.

[Effects of the Invention] As is clear from the above description, according to the present invention, since the inward facing surface of the guide member is subjected to anti-reflection processing, deterioration of lens performance due to the effects of ghost and flare due to internal reflection can be prevented. .

Further, since the fixed lens barrel and the guide member are integrally molded, and anti-reflection processing, assembly work, etc. are not required, the number of parts and assembly steps are reduced, and costs can also be reduced.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing the main parts of an embodiment of the lens moving device of the present invention, Fig. 2 is a perspective view showing a steady rest member for cutting, and Fig. 3A is a perspective view showing the same lens moving device. A vertical cross-sectional view of the zoom lens, FIG. 3B is a cross-sectional view taken along the line 8-1 in FIG. 3A,
FIG. 4 is a perspective view showing the main parts of a conventional lens moving device. 10... Fixed lens barrel 10a, 10b, 10c
... Guide member 24 ... Variator holding/moving frame
24a, 24b, 24C...Guide part 2G
...Compensator holding/moving frames 26a, 26c
...Guide part patent applicant Tamron Co., Ltd. 1st cause 2nd figure 4th figure 3A figure 3B figure

Claims (2)

[Claims] (1) In a moving device in which one or more guide balls are provided in a fixed lens barrel parallel to the optical axis, and a lens holding/moving frame is attached to the guide balls so as to be movable parallel to the optical axis. , a concave or convex guide member is provided within the fixed lens barrel and extends parallel to the optical axis apart from the guide ball, and the guide member is fitted into or fitted into the holding/moving frame and extends in the optical axis direction. 1. A lens moving device comprising: a slidable convex or concave guide portion. (2) The lens moving device according to claim (1), wherein the top surface of the convex guide member or the bottom surface of the concave guide member is subjected to antireflection processing.