JPS62129807A - Lens holding device - Google Patents

Abstract

PURPOSE:To improve the precision of a device for a long period by providing the external frame of a lens barrel, an engagement part perpendicular to an optical axis which is provided to the lens barrel, an engagement piece which is movable while engaging the engagement part, and a means which fixes the engagement piece with the external frame. CONSTITUTION:An eccentric pin is inserted into a guide hole 39 and the tip of the eccentric pin is engaged with the groove 33 of a split lens barrel 20; and a master lens part 34 is rotated in the optical-axis directions by rotating the eccentric pin to adjust a back focus. At this time, a stopper 37 engages a groove 33, so it moves together with the master lens part 34 and the stopper 37 is formed in a U shape covering a projection part 36 and movable only in the optical-axis directions under the guidance of the projection part 36. A fixing screw 38 is clamped tightly after the adjustment and the eccentric pin is detached from a master flange 35, so that the back focus adjustment is completed. Thus, the outer periphery of the lens barrel is not pressed with strong force directly, so the precision is maintained for a long period.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a lens holding device that can be used in optical equipment such as video cameras.

BACKGROUND OF THE INVENTION In recent years, the applications of optical-related equipment have rapidly expanded due to advances in electronics, and along with this, the demand for improved productivity has also increased. Attempts are being made to improve productivity and reduce costs by using resin for so-called lens barrels that support optical elements.

Hereinafter, an example of the conventional lens assembly mentioned above will be described with reference to the drawings.

FIG. 4 shows a perspective view of a conventional lens holding device, and the structure in which a lens barrel 2 holding several lens groups (1 is one of them) is fixed to another lens barrel 3 is as follows: This is often used to fix a so-called master lens group. To explain in more detail, the lens barrel 3 is supported on the device main body through the mounting hole 5 provided in the 7 flange portion 4 of the lens barrel 3, the lens barrel 2 is fitted inside the lens barrel 3, and the lens barrel The groove 6 provided in the lens barrel 3
After that, the eccentric bottle 10, in which the shafts 8 and 9 are eccentric, is roughly positioned so that it looks into the hole 7 provided in the
By rotating the eccentric bin 10 with the shaft 9 engaged with the hole 7 and the shaft 8 engaged with the groove 6, the lens barrel 2 is moved in the direction of the optical axis of the lens, and the bank focus is adjusted. After the adjustment is completed, screw the screw 12 into the screw hole 11 provided in the lens barrel 3, press the tip of the screw 12 against the lens barrel 2 and fix it, and then remove the eccentric bottle. Focusing of the lens system is completed. (For example, in 1987-
(No. 84914 Publication) Problems to be Solved by the Invention However, with the above configuration, there is no problem at all in the case of a lens barrel using metal parts, but in the case of a lens barrel using a resin material, it may deteriorate over time during use. Due to such changes, the tightening force of the screws decreased, and there was a risk that the position of the lens barrel would move and the focus would shift.

There is also the problem that if the screw is tightened strongly in advance by increasing the tightening force by the amount of the decrease in tightening force, the lens barrel will be deformed and the optical performance will deteriorate.

In view of the above-mentioned problems, the present invention provides a lens holding device that accurately fixes a lens barrel made of resin material over a long period of time.

Means for Solving the Problems In order to solve the above problems, the lens holding device of the present invention includes an outer frame for holding the outer periphery of the lens barrel, and an outer frame provided on the lens barrel in a direction perpendicular to the optical axis. The device includes an engaging portion, a locking piece that engages with the engaging portion and is movable in the optical axis direction, and a fixing means for fixing the locking piece to the outer frame.

Effects of the Invention With the above-described configuration, the present invention does not directly press the outer periphery of the lens barrel with a strong force, so that the lens barrel is less deformed and the resin lens barrel can be accurately fixed for a long period of time.

Examples Below, regarding lens holding devices according to examples of the present invention,
This will be explained with reference to the drawings.

FIG. 1 is a sectional view of a lens holding device according to an embodiment of the present invention, FIG. 2 is a side view, and FIG. 3 is a perspective view of a master lens section.

1 to 3, lenses 21, 22, and 23 are inserted into two identically shaped segmented lens barrels 20 molded from glass-filled polycarbonate resin. The outer peripheral part of the lens 21 is held by a lens holding part 24 on the inner peripheral surface of the divided lens barrel 2o, and the lens 21 is pressed against the lens regulating part 26 by an elastic piece 25 provided on the inner surface of the divided lens barrel 20. This enables positioning in the optical axis direction.

Similarly, the lens 22 is attached to the lens holding portion 27 of the divided lens barrel 20.
, elastic piece 28. The lens 23 is fixed by a lens holding part 301, an elastic piece 31, and a lens regulating part 32.

A groove 33 is provided on the outer periphery of the split lens barrel 2o in a direction perpendicular to the optical axis (circumferential direction), and the two split mirrors 111i12C
B = A master lens section 34 composed of lenses 21, 22, and 23 is housed inside a master 7 lunge 35. The tip 37 of the stopper 37 is guided by the protrusion 36 on the outer periphery of the master flange 36 and is movable in the optical axis direction.
& is engaged with a groove 33 provided on the outer periphery of the split lens barrel 20, and the stopper 37 is fixed to the master flange 35 with three fixing screws. The master flange 35 has a guide hole 39 for an eccentric bin (not shown) for finely adjusting the master lens portion 34 in the optical axis direction.

When assembling and adjusting the lens holding device configured as described above, first, the lenses 21 and 22 are attached to one of the split lens barrels 20.
．． 23 respectively, cover the other split lens barrel 2o, complete the master lens part 34, and install it in the master 7 flange 35. Insert the stopper 37 through the square hole 40 provided in the master flange 35, and insert the stopper 37 into the tip 37a. is engaged with the groove 33 of the split lens barrel 2o, and the fixing screw 3
Tighten 8 lightly.

Next, an eccentric bottle similar to the conventional example is inserted into the guide hole 39, the tip of the eccentric bottle is engaged with the groove 33 of the split lens barrel 2o, and the master lens portion 3 is rotated by rotating the eccentric bottle.
4 in the optical axis direction to perform back focus adjustment. At this time, the stopper 37 is engaged with the groove 33 and therefore moves together with the master lens portion 34. As shown in FIG. It is guided by the starting portion 36 and can move only in the optical axis direction. After the adjustment is completed, the fixing screw 38 is strongly tightened and the eccentric pin is removed from the master 7 lange 36 to complete the back focus adjustment.

As described above, according to this embodiment, the outer frame for holding the outer periphery of the lens barrel, the engaging portion provided on the lens barrel in the direction perpendicular to the optical axis, and the engaging portion that engages with the Since the axially movable locking piece and the fixing means for fixing the locking piece to the outer frame are provided, there is little deformation of the lens barrel, and the resin lens barrel can be accurately fixed for a long period of time.

In the above-described embodiment, the same groove is used as the groove for engaging the stopper and the groove for engaging the eccentric bottle, but it is also possible to provide dedicated grooves for each.

Effects of the Invention As described above, according to the present invention, even when the fixing screw is tightened with a strong force, the outer periphery of the lens barrel is not directly pressed with a strong force, so the lens barrel does not deform and the optical performance is not deteriorated. Therefore, even with a lens barrel made of a resin material, an excellent effect can be obtained in that the lens barrel can be accurately fixed for a long period of time without worrying that the position of the lens barrel will shift due to changes over time.

[Brief explanation of drawings]

Fig. 1 is a sectional view of a lens holding device according to an embodiment of the present invention, Fig. 2 is a side view, Fig. 3 is an exploded perspective view of a master lens section, and Fig. 4 is an exploded perspective view of a conventional lens holding device. It is a diagram. 2o...Split lens barrel, 21, 22.23...
・Lens, 33...Groove, 35...Group/Master flange, 37...Stroller, 38...
··Fixing screws. Name of agent: Patent attorney Toshio Nakao and 1 other person 20
--Ichimura Jx122--Lens゛33--Ichimura Figure 1
35---Master 7 Runcie'37---
-z)7 bar protection--Yen 2-Pill Fig. 3 Fig. 4

Claims (1)

[Claims] a lens barrel that accommodates a lens and is movable in the optical axis direction; an outer frame for holding the outer periphery of the lens barrel; an engaging portion provided on the lens barrel in a direction perpendicular to the optical axis; A lens holding device comprising: a locking piece that engages with an engaging portion and is movable in the optical axis direction; and a fixing means for fixing the locking piece to the outer frame.