JPS59148012A - Zoom lens device - Google Patents

Abstract

PURPOSE:To simplify the constitution of a zoom lens device by forming a cam surface for moving the 2nd lens on the end surface of a holding member for the 1st lens. CONSTITUTION:A zoom ring 30 is rotated to rotate the holding member 16 for the 1st lenses 10-14 through a pin 26, and it moves back while rotating along a cam groove 28 cut in a lens barrel 18. The 2nd lens 22, on the other hand, moves back according to the rotation of the 1st lens holding member 16 to vary the focal length because a spring 38 is interposed between the lens barrel 18 and the holding member for the 2nd lens and one terminal of the holding member 24 for the 2nd lens serves as a cam follower 40 and abuts on an end surface cam part formed on the end surface of the holding member 16 for the 1st lens. Thus, a cam surface and the cam follower are provided to the end surface of the lens holding member to simplify the constitution.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a lens assembly, particularly a so-called zoom lens device capable of changing image magnification, and is effective for use in, for example, videos, cameras, etc. .

Conventional Structure and Problems Generally, a zoom lens assembly consists of a first zoom lens and a second zoom lens that change the image magnification by moving along the optical axis.

In conventional zoom lens devices, the structure of the sliding guide means for the two moving lenses is complicated and expensive.

OBJECTS OF THE INVENTION The present invention provides a zoom lens device that solves the above-mentioned conventional problems, has a simple structure, and can be manufactured at low cost.

Ifllt Construction of the Invention The lens device of the present invention has a first lens device that can change the image magnification by moving in the optical axis direction.
A zoom lens group and a second zoom lens assembly, and a first zoom lens assembly that holds the first zoom lens group.
M4A, a second zoom lens holding part that holds all of the second zoom lens 7111, and a second zoom lens holding part that engages with the two lens holding parts and rotates the 17th lens holding part about the optical axis. a lens barrel that freely and slidably guides the second zoom lens holder in the optical axis direction, controls rotation of the second zoom lens holder about the optical axis, and slides the lens barrel in the optical axis direction; and the second zoom lens holder A tool 9ii1L for forcing the lens member in the direction of the first lens holding member, and a cam means on an end surface of at least one of the two lens holding members on the side opposite to each other. 114, so as to drive the second zoom lens holding member in the optical axis direction by the cam means following rotation of the first zoom lens holding member around the optical axis and movement in the optical axis direction. It is composed of

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings.

In FIG. 1, the outer circumferential surface of the first zoom lens holder 16 that holds the first zoom lenses 1Q and 12° 14 is in a fitting relationship with the guide portion 2Q on the inner circumferential surface of the lens barrel 18. The movement is as if the lens barrel 1B is slidably guided by a guide portion 20 shown in the drawings.

Similarly, the second arm lens 22 is held by the second
-1- Also the outer circumferential surface of the lens holding part 24" Niki Kagami 111
It is in a fitting relationship with the guide portion 20 on the inner circumferential surface of 1s, and movement in the optical axis direction is as if guided by sliding.

In fact, the movement of the two zoom lens holders 16 and 24 in the optical axis direction is guided by guide portions 20 on the inner peripheral surface of the lens barrel 18 having the same 71-mm inner diameter. The movement of the first zoom lens holding member 16 and the second lens holding member 24 in the optical axis direction is achieved by moving the pin 26 implanted in the lens holding member 16 into the bell barrel 18. The first cam groove 28 formed therethrough is in a mating relationship with the first kite 132 parallel to the optical axis of the zoom lens 30, and
The pin 34 implanted in the smoothens holding part 4: J24 is in an engagement relationship with the second guide groove 36 extending in the XJi direction to the optical axis of the L marking barrel 18. 1. A spring 38 is arranged between the lens holding member 24 and the second
The zoom lens holding member 24 is biased parallel to the optical axis in the direction of the first zoom lens holding member 16, and the cam follower portion 40 provided on the second zoom lens holding member 24 is biased toward the first zoom lens holding member 24.
The end face cam part 42 provided on the zoom lens holding part 16 faces and abuts against it, and the second zoom lens holding part 24 follows the movement of the first zoom lens holding part 16 in the optical axis direction. is configured to move in the light i1t+l+ direction, and this can be done by rotating the zoom link 30 around the optical axis.

FIG. 2 is a diagram showing the relationship between the position of the nut lens from a certain reference position and the angle of rotation θ about the optical axis of the zoom link. In the figure, curve a corresponds to the first zoom lens, and curve tab corresponds to the second zoom lens. As shown in FIG. 1, the second nude lens holding part 24 follows the movement trap of the first sumlens ('; transfertlit
3, but at this time, the first zoom lens holding section (116
also rotates around the optical axis, and the position of the end cam that comes into contact with the cam follower sound 1!40 changes depending on the rotation angle of the zoom link 30, the gap 1 between curves a and b shown in FIG. However, the displacement curve of the end cam portion 42 is different from that of the zoom ring 3.
By correcting the change in the gear knob 1 corresponding to the rotation angle o, the distance from the reference position of the first zoom lens and the second zoom lens is calculated by the amount represented by the two curves a and b in Fig. 2. It is formed to look like this.

In the above-mentioned (74 configuration), the pin 26 that rotates the zoom link 30 around the optical axis receives a biasing force around the optical axis, rotates around the optical axis along the cam groove 28 provided in the lens barrel 18, and rotates the zoom link 30 around the optical axis. Therefore, the first lens holding part 16 rotates around the optical axis and moves in the optical axis direction following the movement of the bottle 26.The second lens holding part 24 is moved by the cam follower part by the spring 38. 40
is pressed against the end face cam portion 42. Therefore, due to the rotation of the first rotation holding part 16 around the optical axis and the movement in the optical axis direction, the end face force J of the cam follower part 40 and the part 4 are
The abutment position of 2-\ changes, and the second lens holding part 24 moves in the optical axis direction following the curve of the end face cam part 420.

That is, the first zoom lens holding part 16 moves in the optical axis direction as shown by curve a in FIG. 2 according to the rotation angle of the zoom cylinder 30, and the second zoom lens holding part 4J24 The image magnification is changed by moving in the optical axis direction as shown by the curve in FIG.

Effects of the Invention As explained in detail above, the zoom lens device of the present invention includes an elastic member set such as a spring that is biased in the direction of the moon, and
Since cam means that engage with each other are provided on the opposite end surfaces of the two zoom lens holders H to drive the zoom lens, it is extremely simple.
It has the excellent feature of being able to be manufactured at low cost with an integrated process.

Furthermore, since the movement of the two movable zoom lens holding parts in the optical axis direction is guided by the guide part 20 on the inner peripheral part of the lens barrel 14 having the same dimensions and inner diameter, the processing accuracy of the lens barrel 14 can be improved. Only one guide surface is required (17H construction is simple, processing can be done with high precision and quickly, and productivity is greatly improved. In fact, the use of two lens holders is greatly improved. It has the advantage that it is easy to achieve concentricity, and it also improves the performance of each lens assembly.

In the above embodiment, the engagement relationship between the end cam portion 42 and the cam follower portion 40 is a sliding relationship e, but the force l
・) A rotating roller or the like may be arranged in the A lower part to form a rolling contact relationship.

The end cam part is attached to the first zoom lens holding part H, and the second
A cam follower part was installed in the Soumerenne holding unit, but the first
There is no problem in providing a cam follower section on the second zoom lens holding section and an end cam on the second zoom lens holding section.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an embodiment of the present invention, and FIG. 2 is a characteristic diagram showing the relationship between the position of the zoom lens and the rotation angle of the lens and IJ sync in the same embodiment. 10.12.14... 1st summurence, 16.
---First zoom lens holder, 18... Lens barrel, 20... Guide ff1L22... Second zoom lens, 24... Second zoom lens holder 38...-Spring, 40...-Cam follower section, 42,..., g7 surface cam section. Name of agent: Patent attorney Toshio Nakao and 1 other person
1 figure

Claims (1)

[Claims] A first zoom lens group and a second zoom lens group that can change image magnification by moving in the optical axis direction, a first zoom lens holding member that holds the first zoom lens group, and a second zoom lens group. a second zoom lens holding member that holds a lens group; and a second zoom lens holding member that engages with the two lens holding members and guides the first zoom lens holding member rotatably around the optical axis and slidably in the optical axis direction. , and a lens barrel that restricts rotation of the second zoom lens holding member around the optical axis and slides and guides the second zoom lens holding member in the optical axis direction; and a lens barrel that moves the second zoom lens holding member in the direction of the first zoom lens holding member. the first zoom lens holding member is provided with an elastic member set for urging, and has a cam means on an end surface of at least one of the two lens holding members on the side that is in line with the other, and the optical axis of the first zoom lens holding member is The cam means drives the second soot lens holder in the optical axis direction following the rotation around the circumference and the movement in the optical axis direction (111).