JPH0112258Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a lens mount that supports a long projection lens of a slide projector.

[Conventional technology]

BACKGROUND ART Recently, at various exhibitions and academic conferences, it has become extremely common to use multiple slide projectors to project various types of images onto a screen either sequentially or simultaneously.

In the case of a large venue, the location of the slide projector is usually limited to a place far away from the screen, and it is necessary to maintain a certain level of brightness inside the venue, so it is not used. The projection lens also requires a large aperture lens with a long focus and a small F number.

[Problem that the invention attempts to solve]

However, commonly used slide projectors are intended for use at home or in small halls, and the interchangeable lenses are held by felt or felt provided on the outer circumferential surface of the lens barrel and the inner circumferential surface of the lens mounting mount. It relies on frictional force with leaf springs, etc., and there is considerable play between the two.

Therefore, when using a short, lightweight, small-diameter projection lens, the optical axis of the lens can be kept perpendicular to the center of the slide surface by the frictional force between it and the inner peripheral surface of the lens mounting mount. In the case of a long, large-diameter projection lens, the front part of the lens barrel sags due to its weight, the optical axis is oblique to the slide surface, causing distortion and unilateral blur in the projected image, and focus adjustment becomes extremely difficult. There was a problem with that.

In addition, the rear part of the housing is supported by fixed legs provided on both the left and right sides, and the front part is supported by adjustable legs for adjusting the elevation angle provided in the center. In the case of a projector mounted on the screen, there was also the problem that the housing would tilt due to the weight of the projection lens.

The purpose of this invention is to provide a lens mount that can solve these conventional problems.

[Means for solving the problem] Therefore, the lens mount according to this invention has an opening through which the projection lens is inserted in the vertical surface of the approximately L-shaped frame that can be attached and detached to a slide projector in which a plurality of projection lenses can be exchanged. A pair of adjustment screws are screwed into the horizontal surface portion at a plurality of symmetrical positions with respect to the vertical plane including the lens optical axis so that the height can be adjusted. The lower surface of the barrel of the projection lens is slidably supported.

[Effect]

By configuring as described above, a frame body is attached to the front of the slide projector, and one pair of frames is placed at a symmetrical position corresponding to the projection lens to be used among a plurality of symmetrical positions with respect to a vertical plane including the lens optical axis on its horizontal surface. By screwing in the adjustment screw and adjusting the height of its tip, the optical axis of the attached projection lens can be made perpendicular to the center of the sliding surface.

In this state, the projection lens is held in the correct position by the mount of the slide projector and the tip of the adjustment screw, and even if the lens barrel is moved back and forth to adjust the focus, the outer circumferential surface of the lens barrel will not touch the adjustment screw. The lens optical axis does not change due to free sliding of the tip.

In addition, when replacing the projection lens, unscrew the adjustment screw from the horizontal surface of the frame, screw it into the symmetrical position corresponding to the replaced projection lens, and adjust the height to adjust the projection lens light. The axes can be aligned with the regular axes.

〔Example〕

Embodiments of this invention will be described below with reference to FIGS. 1 to 4 of the accompanying drawings.

The figure shows an embodiment of this invention.
consists of a horizontal surface portion 11, left and right side views 12, 13, and a vertical surface portion 14, and the horizontal surface portion 11 has a plurality of pairs of screw holes 11a, 11a, 11b, 11b, 11a, 11b, 11a, 11b, 11a, 11b, 11a, 11a, 11a, 11a, 11a, 11b, 11b, 11
c, 11c are provided.

A pair of adjustment screws 2, 2 are removably screwed into these screw holes 11a to 11c, and a cap 3, made of a synthetic resin with a low coefficient of friction such as polyamide, polyacetal, or fluorine resin, is attached to the tip of the adjustment screw 2, 2. 3 are each screwed on.

Further, a support member 4 is provided on the inner surface of the left side portion 12 so as to be slidable up and down through a long hole 4a, and can be fixed at a required height with a set screw 5 and a nut 6.

Further, a fixing screw 7 constituting a fixing means to the slide projector 20 is screwed onto the upper bent portion 14a of the vertical surface portion 14, and the projections 14b and 14c are inserted into the positioning grooves 20b and 20c of the slide projector 20. When the fixing screw 7 is tightened, the frame 1 is placed in the opening 14d of the slide projector 20.
The lens mounting mount 20a can be fixed with its center concentric with the lens mounting mount 20a.

As a result, the vertical plane including the lens optical axis of the projection lens mounted on the lens mounting mount 20a passes through the center line XX of the frame horizontal surface section 11, and the screw holes 11a, 11a, 11b, 11b, 1
1c and 11c are symmetrical positions with respect to the vertical plane.

In the figure, reference numeral 21 is an adjustable leg for adjusting the elevation angle provided at the front of the slide projector 20, and 22 is a rotary magazine that accommodates a large number of slides and rotates.

Next, the operation of the embodiment having such a configuration will be explained.

When the projections 14b and 14c of the lens mount 1 are inserted into the positioning grooves 20b and 20c of the slide projector 20 and the fixing screws 7 are screwed in, the vertical surface portion 1 of the frame 1
4 is in close contact with the front surface of the slide projector 20, and the opening 14d is fixed to the slide projector 20 so as to be substantially concentric with the lens mounting mount 20a.

The screw hole (in the illustrated embodiment, the screw hole 11a,
11a), and screw the caps 3, 3 onto the tips thereof.

In this state, attach the required long focus large diameter projection lens 30 to the lens attachment mount 20a, rotate the adjustment screws 2, 2, and support the lower surface of the lens barrel with the caps 3, 3 to set the lens optical axis at a predetermined value. It is fixed by nuts 8, 8 so as to coincide with the projection axis of .

Furthermore, after rotating the adjustment legs 21 of the slide projector 20 to match the projection screen with the screen surface, the support member 4 is moved up and down to make the slide projector 20
The support member 4 is fixed at that position by the set screw 5 to prevent the projection screen from tilting due to the weight of the projection lens 30.

Finally, when the projection lens 30 is moved back and forth by operating the focus adjustment member (not shown) of the slide projector 20, the lower surface of the lens barrel slides into contact with the caps 3, 3, and focuses back and forth in the optical axis direction. If the projection lens 30 is a zoom lens, the size of the projection screen can be freely changed by rotating the zoom ring.

In addition, adjust screw 2 depending on the projection lens used.
By screwing the lens into one of the screw holes 10a, 10b, and 10c, projection lenses of any size can be accommodated.

Further, instead of screwing the caps 3, 3 onto the adjusting screws 2, 2, the adjusting screws themselves may be made of synthetic resin having a small coefficient of friction.

Furthermore, instead of providing screw holes at a plurality of symmetrical positions with respect to the vertical plane including the lens optical axis in the horizontal surface portion 11, elongated holes are provided symmetrically with respect to the vertical plane including the lens optical axis, and the adjustment screws are inserted into the elongated holes. It goes without saying that the means for fixing the frame 1 to the slide projector 20 may have a different structure depending on the type of slide projector.

Furthermore, this lens mount is not limited to slide projectors, and can be applied to cine projectors, real projectors, etc. without any problems.

[Effects of the invention] As described above, the lens mount according to this invention has an opening through which the projection lens is inserted, and means for fixing it to the slide projector, in the vertical surface of the approximately L-shaped frame that can be attached to and detached from the slide projector. At the same time, a pair of adjustment screws are screwed onto the horizontal surface part at a plurality of symmetrical positions with respect to the vertical plane including the lens optical axis so that the height can be adjusted, and the tip of the adjustment screw can freely slide on the lower surface of the projection lens barrel. As a result, the front part of the long projection lens barrel, which tends to sag when attached to the lens mounting mount due to its weight, is lifted, and the optical axis is aligned perpendicular to the center of the slide surface. It becomes possible to do so.

As a result, the focus can be easily adjusted without causing distortion or blurring of the projected image.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing an embodiment of this invention, Fig. 2 is a plan view thereof, Fig. 3 is a side view showing the state in which it is mounted on a slide projector, and Fig. 4 is a front view thereof. . DESCRIPTION OF SYMBOLS 1... Frame body, 2... Adjustment screw, 3... Cap, 4... Support member, 5... Set screw, 7... Fixing screw (fixing means), 11... Horizontal surface part, 12...
Left side view, 13... Right side part, 14... Vertical surface part, 20... Slide projector, 30... Projection lens.

Claims (1)

[Claims for Utility Model Registration] 1. An opening through which the projection lens is inserted, and means for fixing it to the slide projector, in a vertical surface of a substantially L-shaped frame that is removably attached to a slide projector in which a plurality of projection lenses can be exchanged. In addition to providing
A pair of adjustment screws are screwed into the horizontal surface part at a plurality of symmetrical positions with respect to the vertical plane including the lens optical axis so that the height can be adjusted, and the tip of the adjustment screw can freely slide on the lower surface of the lens barrel of the projection lens. A lens mount characterized by supporting the lens. 2. The lens mount according to claim 1, wherein the adjustment screw has a cap made of a material with a small coefficient of friction screwed onto the tip of the adjustment screw that slides into contact with the projection lens barrel. 3. The lens mount according to claim 1 or 2, wherein the frame has a support member that prevents the slide projector from tilting due to the weight of the projection lens.