JPS60129733A - Projecting lens and film projector - Google Patents

Abstract

PURPOSE:To improve operability at the replacement of a lens and positional accuracy by forming an engaging part to be attachably/detachably engaged with a device body in a direction rectangular to an optical axis on the peripheral part of a projecting lens. CONSTITUTION:A lens fixing member 30 formed unitedly with a hook part 30c is fitted to the device body. A hook part 20i to be engaged with the hook part 30c is formed on the periphery of a lens holder supporting member 20c in the direction rectangular to the optical axis of the lens. To detach the lens, the hook part 20i is picked up and pulled in the arrow Y direction. At the attachment of the lens, the lens is inserted in the reverse direction against the Y direction through a guide plate of the fixing member 30, so that the hook part 30c is engaged with the hook part 20i and the lens is simply fixed. Thus, the operation for the replacement of the lens is easy and simple and the positional accuracy can be highly maintained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a projection lens and a film projection device using the same, such as a microfilm reader or a microfilm reader printer, and in particular, a projection lens that is replaceable to change the projection magnification. The present invention relates to a film projection device.

A conventional device using this type of projection lens, such as a microfilm reader, generally has a configuration as shown in FIG. This is achieved by irradiating illumination light from below onto the film F held between the pressure plate glass 1a and the lower plate glass 1b.
A projected image of the film F is formed on the transmission screen 6 via the second mirror 5. The illumination light is generated by condensing the light emitted by the illumination lamp 7 with a reflecting mirror 8, condensing lenses 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 1a, the lower glass plate 1b, and the handle 1 (together constitute the film carrier 1, and by moving the handle 1C back and forth and left and right, the pressure plate glass 1
The film F held between the lower glass plate 1b and the lower glass plate 1b is appropriately aligned.

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 disposed inside the lens portion 3a according to its projection magnification. The lens part 3a is a lens holder 3
b so as to be removably fitted from above. The lens holder 3b is screwed into a holder support member 3c,
This 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. When the leaf spring 13 extending from the main body side presses the post 3d downward, the holder support member 3c is pressed onto the pressure plate glass la, and the position in the front, rear, left and right directions is also restricted. In addition, the lens holder 3b
A ring 3e is provided around the ring 3e, and a longitudinal knob 3f is fitted into a screw hole formed in the ring 3e 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 1. 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. In addition, when converting the projection magnification, pull out the lens part 3a upward from the lens holder 3b,
This is done by replacing the lens with another lens having the desired magnification.

However, when trying to replace the lens section 3a to change the projection magnification, the first
mirror 4 is disposed, and there is almost no space left for the insertion and removal of the lens portion 3a. Therefore, the only option is to move the entire projection lens 3 out of the lower range of the first mirror 4, or to remove the first mirror 4 and then replace the lens portion 3a. Therefore, the operation for converting the projection magnification becomes complicated, and the position of the lens cannot be accurately maintained due to positional errors due to movement of mirrors and misalignment between the lens section 3a and the lens holder 3b. There were drawbacks.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a projection lens and a film projection apparatus which can eliminate the above-mentioned drawbacks and which can be easily replaced, have good operability, and can maintain high positional accuracy.

In order to achieve the above object, the present invention provides an apparatus for engaging the outer circumference of a detachable projection lens with the main body of a film projection device by moving the projection lens in a direction substantially perpendicular to its optical axis. each engaging portion is provided so that the projection lens is uniformly set at a predetermined position of the main body by the engagement.
The projection lens can be freely attached and detached by a simple operation.

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

An embodiment of the present invention is schematically illustrated as a whole based on FIG. Here, as in FIG. 1, the film carrier 1 is integrally constituted by a pressure plate glass la, a lower glass plate 1b, and a handle 1C. In order to illuminate the film F held between the pressure plate glass 1a and the lower glass plate 1b, the light from the illumination lamp 7 is focused by a concave reflecting mirror 8, passed through a condenser lens 9.10, and then reflected by a cold mirror 12. Only the cold light is directed upward by 90 degrees and further effectively guided to the film F via the condenser lens 11. The light transmitted through the film F passes through the projection lens 20 fixed by the lens fixing member 3O, which is a feature of the present invention.
via the first and second mirrors 4. -5 and forms a projected image on the transmission screen 6.

An embodiment of the projection lens 20, which is a feature of the present invention, will be described based on FIGS. 3 to 8. As shown in the plan view of FIG. 3, the projection lens 20 schematically includes a lens portion 20a, a lens holder 20b, and a holder support member 2.
0C so that they can be attached and detached from each other, and integrally configured so that the focus can be adjusted by rotating as described later.

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 20'd are arranged radially along the outer periphery 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 it is also possible to have a plurality of handle portions 20 (1 You can also hold it by wrapping it from the outside.Of course,
Other shapes, such as elongated rods, can 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 cylindrical portion 20e
The lens part 20a is tightly fitted and dropped into the lens part 20a, and normally the claw part 2Of engages with the stepped part 20g of the lens part 20a, so that the lens part 20a and the lens holder 20b are integrally formed. becomes 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 the cylindrical portion 20h, with its center axis aligned, and further provided with an elastic member 20j interposed therebetween. The hook portion 20i acts as an engaging portion with the main body of the device, as will be described in detail later. Elastic member 20j
As is clear from FIG. 7, it has a shape that is rotationally symmetrical by 120 degrees 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.
Furthermore, it allows for appropriate movement in the vertical direction of the figure, and also allows for so-called gyroscopic movement, which allows for tilting of the central axis k in either a slanted direction or a slanted direction. Further, a threaded portion 20k is formed inside the cylindrical portion 20h, and the lens holder 20
As shown in FIG. 4, the threaded portion 20/ formed on the outer lower side of This is to change the relative position of the lens part 2 fitted in the lens holder 20b.
By changing the distance between Oa and the film F shown in FIG. 2, the projected image of the film F formed on the transmission screen 6 is focused.

Next, the means for engaging the projection lens 2O and the main body of the apparatus, which is the most characteristic feature of the present invention, will be described. The main body of the apparatus is provided with a lens fixing portion 30 as shown in FIGS. 2, 9, and 10.

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

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 when the hook portion 20i of the holder support portion 20C is completely housed in the guides 30a and 30b, the hook portion 30C engages with the hook portion 20i. , is fixed in place as shown in FIG. Such engagement means are not limited to the hook portions 20i, 30C, and the intended purpose can also be achieved by using, for example, a so-called roller catch, ball catch, magnet, or the like. Also, the hook 30C is inserted from below,
The hooks 20i may be configured to engage from above.

Note that the upper guide 30a and the lower guide 30b are
As shown in the figure, the projection lens 20 is kept at a constant distance from the pressure plate glass la so as to be in close contact with the pressure plate glass la,
It is also desirable to arrange it horizontally. The above-mentioned interval is set so that the projection lens 2O is appropriately pressed onto the pressure plate glass la by the elastic deformation of the elastic member 20j when the projection lens 2O is mounted, as shown in FIG.

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) When removing the projection lens 20, (1i) When attaching, and (11) When focusing the projection lens 20 will be explained together with their respective 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, their engagement can be released by simply pinching the left end of the hook portion 20i and pulling it with a moderate 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 20, it is possible to easily take out only the projection lens 20 without having to move or remove it. Furthermore, the hook portion 20i is connected to the projection lens 20.
Since it is provided continuously around the outer circumference, the part to be pinched is not limited to one place (it can be pinched from any direction, and the force is shared by pinching in three places using both hands). , it can also be pulled out more easily.

Ql) At the time of installation: Select the desired one from among the projection lenses 20 with various magnifications prepared in advance. Since the hook portion 20i is continuously formed on the outer periphery of the projection lens 20, when the projection lens 20 is attached to the main body, any part of the hook portion 20i can be pinched from any direction.

Then, it is lightly pinched and slid on the pressure plate glass la, and inserted into the lens fixing member 30 from the direction of the arrow X shown in FIG. When the hook portion 20i engages with the hook portion 30C, attachment to the predetermined position is completed. In this manner, even when the mirror 4 is attached, it is not necessary to move the mirror 4, etc., and the mirror 4 can be easily and reliably used. Furthermore, the lens portion 20a
There is no need to install the lens holder 20b and the holder support member 20C separately (because they can be installed as one piece from the beginning, there is no possibility that the relative positions of these individual members will be distorted each time they are replaced. High accuracy can be maintained.

Further, the hook portion 20i includes upper and lower guides 30a.

The holder support member 20C is securely clamped and held in its position by the holder support member 20B through the elastic member 20j having a specific shape and movement direction (as shown in FIGS. 7 and 8).
is combined with 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 la changes in the vertical direction, the holder support member 20C performs vertical movement and gyro movement as shown in FIG. There is no deviation in the relative position of the front, rear, right, and left sides of the pressure plate glass 1a, and subtle deviations of the optical axis are prevented and accuracy is improved.

(iii) Focusing: Focusing is performed by rotating the lens holder 20b with respect to the holder support portion 20C and changing its 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 knob part is not limited to one place, and the handle part 20 at the most easily operated position can be pinched from any direction. It is also possible to operate the device while holding it in a wrap-around manner, giving a large degree of freedom in operating the device.

As another example, FIG. 12 shows a lens fixing member 30 in which two hook portions 30C are formed.

FIG. 13 is a sectional view taken along the line E-E. By providing a plurality of engagement points in this way, it is possible to more reliably and accurately position the projection lens.

Further, FIG. 14 shows another embodiment of the holder support member 20C. In this case, instead of the continuous circular hook portion 20i as shown in FIG. 7, a plurality of hook portions 20m are formed intermittently in a circular shape. Even in this case, easy engagement with the hook portion 30C on the main body side is possible,
It accomplishes the intended purpose. Moreover, this figure shows an example without an elastic member, and the elastic member can be released by maintaining the accuracy of the hook portion 3Qc on the main body side.

Furthermore, in the embodiment described above, the holder support member 2
Although the 0C is shown as being circular, it is not limited to this, and may have any shape as long as it is easy to attach and detach and can be reliably positioned. For example, even if the lens has an elliptical, pentagonal, or hexagonal shape, the same effect can be obtained by providing a lens fixing member having a shape corresponding to the shape.

As described above, the present invention includes an engaging part on the outer peripheral part of the projection lens, and the engaging part is completely connected to another engaging part formed on the projector main body side from a substantially horizontal direction. Because the projection lens can be replaced, even if there is no space above the lens, it is possible to attach and remove the projection lens without moving any other optical system.
Therefore, it is possible to maintain an optical system with excellent operability and high precision, 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. FIG. 4 is a partial sectional 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. FIG.
-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 CC sectional view of FIG. 7,
FIG. 9 is a plan view showing an embodiment of the lens fixing member according to the present invention, FIG. 10 is a sectional view taken along line DD in FIG. 9, and FIG. 11 is a front view showing a state in which the projection lens is attached to the lens fixing member. A partial partial view, FIG. 12 is another example of the lens fixing member,
FIG. 13 is a sectional view taken along the line EE in FIG. 12, FIG. 14 is another embodiment of the holder support member, and FIG. 15 is a front view of FIG. 14. 20... Projection lens, 20a... Lens section, 20b
...Lens holder, 20c...Holder support member, 2
0d...handle part, 20e...cylindrical part, 20f...
・Claw part, 20g...Step part, 20h...Cylindrical part,
20i...Hook part, 20J...Elastic member, 2
0, 20A'...screw part, 20m...hook part,
30... Lens fixing member, 30a... Upper guide,
30b downstream guide, 30C... hook part, 30
d...Tip. Figure 1 Figure 2 Figure 4 Figure 5 Figure 6 Figure 12 Figure 30 Figure 13 Figure 14 Figure 15

Claims (2)

[Claims] (1) A projection lens that can be attached to and detached from a film projection device, wherein an engaging portion that is detachably attached to the main body of the device is provided on the outer periphery of the projection lens in a direction substantially perpendicular to the optical axis of the projection lens. A projection lens characterized by: (2) In a film projection device having a detachable projection lens, the projection lens is detachably attached to the main body of the device in a direction substantially perpendicular to the optical axis of the projection lens, and when attached, the projection lens is attached to the main body of the device. A film projection device characterized in that engaging portions are provided on the outer circumferential portion of the projection lens and on the main body, respectively, so as to be arranged at predetermined positions.