JPS60129734A - Projecting lens - Google Patents

Abstract

PURPOSE:To remove the positional shift of a lens and to provide a highly accurate photographing lens by arranging an elastic member for contacting the lens against a body on the peripheral part of the photographing lens rotationally symmetrically around an optical axis. CONSTITUTION:A ring-like hook part 20i formed on the periphery of a lens holder supporting member 20c through the elastic member 20j and the elastic member 20j is formed as a rotationally symmetrical shape by 120 deg. around the center axis of a cylindrical part 20h. When the hook part 20i is fixed on the body, the cylindrical part 20h is inhibited to move in a direction rectangular to a shaft k and is moved properly in the vertical direction and the center axis k is inclined to k' or k'' to attain so-called gyro-motion. Consequently, the positional shift of the photographing lens is not generated and the highly accurate photographing lens can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a projection lens used in a Mykyuro film reader, a microfilm reader printer, or the like.

A conventional device using this type of projection lens, such as a microfilm reader, generally has a configuration as shown in FIG. This is pressure plate glass 1a and lower plate glass l.
By irradiating illumination light from below onto the film F held between It forms an image. The above illumination light is
The light emitted by the illumination lamp 7 is focused by a reflecting mirror 8, and then condensed by a condenser lens 9, 10, 11, and a cold mirror 12.
It is obtained by effectively guiding the film F through the film F. The pressure plate glass 1a1, the lower glass plate 1b and the handle 1C together constitute the film carrier 1, and by moving the handle 1C back and forth and left and right, the pressure plate glass 1
Appropriate positioning of the film F held between a and the lower glass plate lb is performed.

The projection lens 3 includes a lens portion 3a, a lens holder 3b, and a holder support member 3C. A plurality of optical lenses are fixedly arranged inside the lens section 3a according to the projection magnification. The lens portion 3a is removably fitted into the lens holder 3b from above.

The lens holder 3b is screwed into the holder support member 3C, and its rotation causes the lens holder 3b to move in the vertical direction.

As shown in FIG. 1, bosses 3d are formed on the front side and the back side of the holder support member 3C. As the leaf spring 13 extending from the main body side presses the boss 3d downward, the holder support member 3C is pressed onto the pressure plate glass la, and its position in the front, rear, left and right directions is also regulated. Also, the lens holder 3
A ring 3e is provided around b, and the ring 3e
A longitudinal knob 3f is fitted into a screw hole formed in the screw hole so as to be movable in the longitudinal direction.

Therefore, in the conventional example described above, the focus of the projected image on the transparent screen 6 is adjusted by pinching the knob 3f and slightly rotating it left and right about the optical path 4. That is, this is done by rotating the lens holder 3b with respect to the holder support member 3C and changing the relative distance between the lens portion 3a and the film F.

Further, when converting the projection magnification, the lens portion 3a is extracted upward from the lens holder 3b [5] and replaced with another lens portion having the desired magnification.

However, the above-mentioned leaf spring 13 rotates in the direction of the arrow R about the fulcrum 13a at °C with the vertical movement of the pressure plate glass la, and the boss 3d also moves in an arc.

Therefore, the projection lens 3 is misaligned in the direction of the arrow S with respect to the pressure plate glass 1a. Even if this positional shift is minute, it has a large adverse effect on the projected image on the transmission screen 6.

It is an object of the present invention to solve the above problems and provide a highly accurate projection lens that is free from positional deviation.

In order to achieve the above object, the present invention provides an elastic member disposed around the outer periphery of a projection lens so as to be rotationally symmetrical about the optical axis of the projection lens. This makes it possible to position the projection lens by pressing it against the main body of the film projection device.

Embodiments of the present invention will be described below with reference to the drawings.

A microfilm reader to which an embodiment of the present invention is applied will be schematically explained based on FIG. 2. Here, as in FIG. 1, the film carrier l is the pressure plate gasis I.
a, a lower glass plate 1b, and a handle 1C. In order to illuminate the film F sandwiched between the pressure plate glass 1a and the lower plate glass 1b, the light from one illumination lamp 7 is focused by a concave reflecting mirror 8, and then passed through a condenser lens 9.
Only the cold light is transmitted through cold mirror 12 through 9
The direction is changed upward by 0 degrees and the film is effectively guided to the film F via the condenser lens 11. The light transmitted through the film F is reflected by the first and second mirrors 4.5 through the projection lens 20 fixed by the lens fixing member 30, which is a feature of the present invention, and is projected onto the transmission screen 6. It forms an image.

An embodiment of the projection lens 20, which is a feature of the present invention, will be explained based on FIGS. 3 to 8.

As shown in the plan view of FIG. 3, the projection lens 20 is generally configured integrally with a lens portion 20a, a lens holder 20b, and a holder support portion A'A' 20c so that they can be attached to and detached from each other. Ru.

As shown in FIG. 4, the lens portion 20a has a plurality of optical lenses L therein, and the optical lenses L have their optical axes aligned with each other and are arranged at predetermined intervals according to the projection magnification. has been done.

The lens holder 20b, as shown in FIGS. 5 and 6,
A plurality of handle portions 20d are arranged radially along the outer circumference of the cylindrical portion 20e. The handle portions 20d have an appropriate length in the radial direction of the lens holder 20b so that they can be easily pinched, and are arranged at approximately constant intervals so that a normal person's fingers can fit comfortably therein. desirable. The handle portion 20d shown in the figure is a substantially rectangular flat plate, but if it is shaped like this, it is possible to provide ample space for inserting fingers, and the plurality of handle portions 20d can be attached to the outside. You can also hold it by wrapping it up. Of course, other shapes, such as elongated rods, may be arranged radially around the outer periphery to achieve the desired purpose. The cylindrical portion 20e is further formed with a plurality of claw portions 20f having appropriate elasticity at rotationally symmetrical positions. As shown in FIG. 4, the lens part 20a is closely fitted into the cylindrical part 20e and is dropped into the cylinder part 20e. Normally, the claw part 20f engages with the stepped part 20g of the lens part 20a, so that the lens part 20a is inserted into the cylinder part 20e. The portion 20a and the lens holder 20b are integrally fixed.

As shown in FIGS. 7 and 8, the holder support member 20c is provided with a ring-shaped hook portion 20i on the outer periphery of a cylindrical portion 20h, with its central axis aligned, and further provided with an elastic member 20j interposed therebetween. The hook portion 20i acts as a retaining portion with the main body of the device, as will be described in detail later. Elastic member 20j
As is clear from FIG. 7, the cylindrical portion 20h has a 120 degree rotational symmetry about the central axis k of the cylindrical portion 20h. This prevents the cylindrical portion 20h from moving in a direction perpendicular to its central axis k when the hook portion 20i is fixed to the main body of the device.
Moreover, it enables moderate movement in the vertical direction of the figure, and also enables so-called gyroscopic movement such as tilting of the central axis k, ' or k''. A portion 20k is formed, and the lens holder 20
It is not provided so that it can be screwed together with a threaded portion 201 formed on the lower outer side of b as shown in FIG.

This is because rotating the lens holder 20b with respect to the holder support member 20 (! By changing the distance to the film F, the projected image of the film F formed on the transmission screen 6 is focused.

Next, the means for securing the projection lens 20 and the main body of the apparatus will be explained. The main body of the apparatus is provided with a lens fixing member 30 as shown in FIGS. 2, 9, and 10.

The lens fixing portion 30 is integrally constituted by an upper guide 30a, a lower guide 30b, and a central hook portion 30e.

The upper guide 30a and the lower guide 30b have approximately U-shaped shapes corresponding to the outer shape of the hook portion 20i so as to wrap around approximately half of the hook portion 20i shown in FIG.
The hook portion 20i can be slid and held between the lower guide 30b and the lower guide 30b. Lens fixing member 300
The two tip portions 30d have hook portions 2 in the direction of the arrow X.
It has a relatively wide opening to facilitate insertion of Oi.

The hook portion 30C is formed with appropriate elasticity, and is engaged with the hook portion 20i when the hook portion 20i of the holder support portion 20c is completely accommodated within the guides 30a and 30b. , is fixed in place as shown in FIG. Such retaining means are not limited to those on the hook portions 2Qi and 3OC, and for example, so-called roller catches, ball catches, magnets, etc. can also be used. Alternatively, a configuration may be adopted in which the hook 30c engages from below and the hook 20i engages from above.

Note that the upper guide 30& and the lower guide 30b are the 11th
As shown in the figure, it is desirable that the pressure plate glasses xaKtJ are arranged horizontally and at a constant interval so that the projection lens 2O is brought into close contact with the pressure plate glass la.

As for the above-mentioned interval, the projection lens 20
When the elastic member 20j is attached, due to the elastic deformation of the elastic member 20j,
It is set so that it is appropriately pressed onto the pressure plate glass la.

Since this embodiment has the above configuration, the exchange and focusing of the projection lens 20 for projection magnification conversion can be performed as follows. (1) At the time of removing the projection lens 20, (11) At the time of attaching, and (B) At the time of focusing, each will be explained together with their functions and effects.

(1) At the time of removal: As shown in FIG. 11, the projection lens 20 is attached to the hook portion 20i.
and the hook portion 30C are elastically engaged from above and below. Therefore, in FIG. 11, they can be released by simply pinching the left end of the hook portion 201 and pulling it with an appropriate amount of force in the direction of the arrow Y over the pressure plate glass la. Therefore, even if the mirror 4 is disposed directly above and close to the projection lens 2o, it is possible to easily take out only the projection lens 2o without having to remove it. Furthermore, the hook portion 20i is connected to the projection lens 2.
Since it is provided continuously on the outer periphery of the 0, the part to be pinched is not limited to one place and can be pinched from any direction, and by using both hands to pinch the two cylindrical parts, the load is divided. It is lighter (and can be pulled out).

(11) When installing: Select the desired one from among the gold-plated projection lenses 2o of various magnifications. Since the hook portion 20i is continuously formed on the outer periphery of the projection lens 2o, when attaching it to the main body, any part of the hook portion 2ol can be pinched from any direction. Then, lightly pinch it, slide it on the pressure plate glass la, and insert it into the lens fixing part 30 from the direction of arrow X shown in FIG. When the hook portion 2oi engages with the hook portion 30C, mounting at a predetermined position is completed. In this manner, even when mounted, the mJ can be used reliably without the need to move the mirror 4 or the like. Furthermore, a lens portion 20a.

There is no need to attach the lens holder 20b and the holder support member 20C separately, and they can be attached as one piece from the beginning. It is possible to maintain high accuracy without any problems.

Additionally, the hook portion 20i is connected to the upper and lower guides 30a13.
0b to maintain its position, and furthermore, as shown in FIGS. 7 and 8, it is connected to the holder support member 20c via an elastic member 2oj having a specific shape and movement direction.

Therefore, the projection lens 20 itself is reliably positioned on the pressure plate glass la. Furthermore, even if the relative positional relationship between the lens fixing member 30 and the pressure plate glass 1a changes in the vertical direction, the holder support member 20C performs vertical movement and gyroscopic movement as shown in FIG.
There is no deviation in the relative position of the optical axis 0 and the pressure plate glass 1a in the front, rear, left, and right directions, and even the slightest deviation of the optical axis is prevented, thereby increasing the positional accuracy.

- (iii) At the time of piston alignment: Focusing is performed by rotating the lens holder 20b with respect to the holder support member 2oc and changing the vertical position. Further, as shown in FIG. 5 and the like, the lens holder 20b is provided with a plurality of handles 20d at regular intervals around its outer periphery. When rotating the lens holder 20b, either handle portion 20d may be pinched and operated. Therefore, the grip portion is not limited to one location, and the handle portion 20 located at the most easily operated position can be gripped from any direction.

In addition, since it is possible to operate while holding the plurality of handles 20d so as to wrap around them from the outside,
A large degree of freedom is given to the operating means.

Other embodiments of the elastic member described above are shown in FIG.
This is shown in FIGS. 3, 14, and 15.

The elastic member 40.70 shown in FIG. 12.15 has a central axis k
It has a rotationally symmetrical shape of 1.80 degrees about.

Even with such a shape, the above-described gyroscopic movement of the projection lens is possible, and deviation in the direction perpendicular to the optical axis can be prevented. Furthermore, a face with a small diameter can also be used, such as the elastic member 50 shown in FIG. Further, as shown in FIG. 14, the same effect can be obtained by arranging the elastic members 60 radially so as to have a shape rotationally symmetrical at 90 degrees about the central axis k. Further, each of the above-mentioned elastic members can have various O-shapes corresponding to the shape of the hook portion 20i.

As explained above, the present invention provides the following features:
By disposing an elastic member that is rotationally symmetrical about the optical axis of the projection lens, the projection lens can be displaced along the pressure plate glass, and even minute lateral deviations in the set position of the projection lens can be prevented. Furthermore, since the structure is simple, it is possible to integrally form the elastic member and its peripheral portion, which is a very excellent effect.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram of a conventional microfilm reader, Fig. 2 is a schematic diagram showing an embodiment of a microfilm reader using a projection lens according to the present invention, and Fig. 3 is an embodiment of a projection lens according to the present invention. 4 is a partial plan view taken along line A-A in FIG. 3, FIG. 5 is a plan view showing an embodiment of the lens holder according to the present invention, and FIG. 6 is taken along line B--
B sectional view, FIG. 7 is a plan view showing one embodiment of the holder support member according to the present invention, FIG. 8 is a C-C sectional view of FIG. 7, and FIG. 9 is an embodiment of the lens fixing member according to the present invention. A plan view showing an example, FIG. 10 is a sectional view taken along the line DD in FIG. It is a top view which shows another Example of the elastic member which is the characteristic of this invention. 20... Projection lens 20a... Lens section 20b... Lens holder 20c...
・Holder support part 20d...Grip part 20e
...Cylindrical part 20f...Claw part 20
g...Step part 20h...Cylindrical
Part 20i...Hook part 20j...Elastic member 20k, 206...Threaded part 30...
・Lens fixing part 30a...Top guide 3
0b...Lower guide '-30c...Hook part 30d...Tip part 40.50.60
．． 70...Elastic member. Patent Applicant Canon Co., Ltd. Agent Wakabayashi Figures 2 to 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 12 Figure 14 Figure 13 Figure 15

Claims (1)

[Claims] A projection lens for a film projection device, wherein an elastic member for pressing the projection lens against the main body of the device is arranged around the outer periphery of the projection lens rotationally symmetrically about the optical axis of the projection lens. A projection lens featuring: