JPS62264038A - Variable power lens device - Google Patents

Abstract

PURPOSE:To easily focus a projection lens with a simple structure by providing a means which holds the projection lens upward and downward movably, a focusing means, a connecting means and constituting a device as specified. CONSTITUTION:The means which holds projection lenses 1 and 2 upward and downward movably in positions equally distant from the center of rotation of a turret base 5, focusing means 11a and 12a which are rotatably provided on the opposite sides of projection lenses 1 and 2 with respect to the center of rotation of the turret base 5 and face these projection lenses 1 and 2, and connecting means (focusing shafts 11 and 12, screw parts 3a-5a, wheel gears 3b and 4b, and warm gears 11b and 12b) which connect these means 11a and 12a to corresponding projection lens holding means and move upward and downward projection lenses 1 and 2 in accordance with the turning operation of focusing means 11a and 12a for the purpose of focusing lenses are provided. Thus, projection lenses in deep positions are focused by focusing means 11a and 12a to improve the operability. Further, the device is made light-weight and compact.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a variable magnification lens device that is used in league printers and the like and is capable of changing the image projection magnification, and more particularly to one in which a plurality of projection lenses can be switched and set.

2. Description of the Related Art In general, microfilms with various reduction ratios are used, which are widely used for recording literature, documents, etc.

In league printers that read and copy these films, there is a limit to the size of an enlarged image that can be projected with a single projection lens having a fixed focal length.

To this end, conventional apparatuses have been provided in which a plurality of projection lenses are built into the apparatus, and a projection lens having a focal length suitable for the purpose can be selectively placed at a projection position. However, in such an apparatus, the reflective optical system for projecting onto the screen is provided protruding from the front side of the apparatus, so the projection lens is disposed at a deep position in the apparatus. For this reason, there was a problem in that it became difficult to adjust the focus of the projection lens.

Therefore, in order to adjust the focus from the front side,
Japanese Patent No. 153,504 proposes a device that performs focus adjustment by vertically moving a turret disc itself that holds a plurality of projection lenses using focusing means provided in front.

In addition, Japanese Utility Model Publication No. 55-52401 discloses that a desired projection lens is selected by moving a holding plate that holds a plurality of projection lenses, and a focus gear provided on each projection lens and one focus adjustment A device that adjusts focus by meshing gears has been proposed.

Problems to be Solved by the Invention However, in the proposed device for moving the turret disk itself up and down, all the projection lenses are moved up and down at the same time to adjust the focus, so focus adjustment is performed every time the projection lenses are switched. It is inconvenient to have to do so.

On the other hand, a device that engages one focus adjustment gear with the focus gear provided on each projection lens requires a mechanism to engage the focus adjustment gear and the focus gear, and malfunction may occur when switching lenses. In order to prevent this, it is necessary to separate the two gears. Therefore, the device becomes complicated and it becomes difficult to make it compact.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems and to propose a variable magnification lens device that has a simple structure and allows easy focus adjustment.

Means for Solving the Problems In order to achieve the above object, the present invention provides means for vertically movably holding each projection lens at a position equidistant from the center of rotation of the turret base, and focusing means rotatably provided on the opposite side of each projection lens with respect to the center of rotation and corresponding to each projection lens, and connecting these focusing means with corresponding projection lens holding means; and a connecting means for moving the projection lens up and down for focus adjustment in response to the rotational movement of the projection lens. Each projection lens and focus means are connected to the projection lens at the projection position so that the focus means connected to the projection lens is placed at a position that is easily adjusted.

Focus adjustment of a projection lens located at a projection position remote from the operator is performed by a focusing means provided around another projection lens located on the near side.

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

1 and 2 are a plan view and a sectional view taken along line A-A' of the variable power lens device in this embodiment. This variable magnification lens device is a reader printer as shown in FIG. 3, and is disposed directly above the illumination device of the optical system, magnifies an image, and projects it onto a screen or photoreceptor.

First and second projection lenses 1.2 having different magnifications are fitted and held in first and second outer cylinders 3, 4, respectively. These two-sided cylinders 3 and 4 each have threaded portions 3a+4a on their outer peripheral walls.
There are two threaded portions 5a formed on the turret stand 5.
and are positioned equidistant from the center of rotation of the turret table 5. This turret stand 5 has a disk shape and is fitted into a fixed stand 6 fixed to the device.
The removal is prevented by means not shown (FIG. 3).

Furthermore, the outer circumferential upper part of the turret stand 5 has a larger diameter than the outer circumferential upper part fitted into the fixed stand 6, and protrudes to the outside of the fixed stand 6, and a knurling portion 5b is provided on the outer circumferential surface thereof. Further, a click ball 8 that engages with a hole 7 of the fixing base 6 is provided at one location in the circumferential direction on the upper part of this outer periphery by a presser spring 9, and the turret base 5 is attached to this click ball 8.
Due to the engagement between the projection lens ltD and the hole 7 provided at a predetermined position, either one of the projection lenses ltD or 2 is positioned so as to stop at the projection position.

A hole 10 is provided at the lens projection position of the fixed base 6, that is, directly above the illumination means (not shown), in order to project light from the direction indicated by the arrow in FIG. 2 onto the screen or photoreceptor through the lens 1 or 2. It is formed.

On the other hand, the first. Turret stand 5 on the outer peripheral wall of the second outer cylinders 3 and 4
Wheel gears 3b and 4b are respectively attached to the protruding parts.
is provided. These wheel gears 3b, 4b mesh with worm gears llb, 12b of the focus shaft 11.12 on the turret stand 5, respectively.

The first of each. The second focus axis 11.12
．． It is a means for adjusting the focus provided for the second projection lenses 1 and 2, and two pairs (D .Both focus axes 11°1
2 has operation knobs at each end.
and worm gears Ilb, 12b, and each of the worm gears Ilb, 12b connects each lens outer cylinder 3,
The operating knob lla l 12a is in a position where it meshes with the wheel gears 3b and 4b of No. 4 and projects on the opposite side from the lenses 1 and 2 with respect to the center of rotation of the turret stand 5.

Next, the operation of selecting a projection lens and adjusting its focus will be explained.

First, by rotating the turret table 5, the projection lens 1 or 2 depending on the film magnification is positioned at the projection position. At this time, the projection lens 1 or 2 is located on the optical axis and enlarges and projects the light from the illumination device onto the screen or photoreceptor.

Focus adjustment of both projection lenses 1 or 2 is performed by rotating the operating knob lla or 12a corresponding to each lens. The rotation of the operation knobs 11a+12j is controlled by the worm gear llb via the focus shaft 11.12.
Rotate 12b. This one - Mugia 11b, 12
The rotation of b is transmitted to the outer cylinders 3 and 4 via wheel gears 3b and 4b.
is rotated, and since the outer cylinders 3 and 4 are screwed to the turret stand 5, they move in the vertical direction, that is, in the optical axis direction.

When adjusting the focus of the projection lens 1 or 2 in this way, use the operation knob lla or 12a located in front to adjust the focus of the projection lens 1 or 2, which is located at the back side from the position where the image is projected, that is, from the operator. It is easy to operate because it can be carried out by Furthermore, since the focus of one lens does not move when the other lens is adjusted, there is no need to readjust the focus each time when the turret table 5 is rotated many times and both lenses are used repeatedly. Note that the focus amount of a lens used in a reader printer is usually about ±2 mm.

The focus amount in this embodiment is the wheel gear 3b,
It is determined by the pitch of the worm gear llb, 12b of 4b or the threaded portion 3aT41, and sufficient performance can be ensured by selecting an appropriate value.

Further, in this embodiment, two lenses are used to adjust the focus, but the present invention can also be used when three or more lenses are arranged on the turret disk.

Furthermore, in this embodiment, a worm gear and a wheel gear are used as a means of connecting the outer cylinder that holds the lens and the focus shaft for each lens, but other means, such as a pinion on the focus shaft side, are also used. A rack may be provided on the outer wall of the outer cylinder, and the focus axis and the outer cylinder may be interlocked by coupling them together.

As described in detail, in the present invention, in a variable magnification lens device having a plurality of projection lenses, a focusing means for adjusting the focal point of a projection lens is arranged opposite to the projection lens with respect to the rotation center of the turret table. Since it is provided on the side, the focusing means provided on the front side can adjust the focus of the projection lens, which is located at the projection position and is located at a distance from the operator, thereby improving its operability. Also, one)
Since focus adjustment of the projection lens does not cause other lenses to move, there is no need to perform focus adjustment each time the projection lens is repeatedly switched and set. Also,
Since the configuration is simple, the device can be made lighter and more compact.

[Brief explanation of drawings]

1 and 2 are a plan view and an A-A' sectional view of a variable magnification lens device according to an embodiment of the present invention, and FIG. 3 is a perspective view showing a reader printer in which a variable magnification lens device according to an embodiment of the present invention is installed. It is. 1...First projection lens 2...Second projection lens 3...First outer cylinder 4...Second outer cylinder 5...Turret stand applicant Minolta Camera Co., Ltd. No. 3 @ -〇 He . Shinto 1 blowout

Claims (1)

[Claims] 1. In a variable magnification lens device that changes the image projection magnification by switching and setting a plurality of projection lenses on a turret base based on the rotation of the turret base, means for holding each of the projection lenses in a vertically movable manner at a separate position; It is characterized by comprising a focusing means, and a connecting means that connects each of these focusing means with a corresponding projection lens holding means, and moves the projection lens up and down for focus adjustment in accordance with the rotational movement of the focusing means. Variable magnification lens device.