JPH0545550A - Lens holding structure - Google Patents

Abstract

PURPOSE:To provide a lens holding structure capable of rightly fixing a lens in a lens frame and also surely adjusting an optical axis with reference to a lens barrel with accuracy. CONSTITUTION:A tapered surface 2b which is connected with a groove 2a formed in a circumferential direction is formed on the outer circumferential part of the lens barrel 2 for fixing the lens 3, and it is fitted in the groove with keeping a prescribed clearance with reference to the circumference of the lens barrel 1, and by pressing the semispherical leading end part 5b of a screw member 5 which is screwed and fixed while facing the outer circumferential surface of the lens barrel 1 against the tapered surface 2b, the optical axis of the lens 3 is made to agree with the axial core of the lens barrel 1 and also by simultaneously pressing it against an abutting wall 1b, the lens frame 2 is fixed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens holding structure for housing and fixing a lens in a lens frame or further in a lens barrel.

[0002]

2. Description of the Related Art In many cases, a lens is housed in a lens frame based on its outer diameter, and the lens frame is incorporated into a lens barrel circle based on its outer diameter. As a result, the optical axis of the lens may deviate from the axial center of the lens barrel by a so-called optical axis shift that exceeds the allowable amount.

In order to suppress the deviation of the optical axis, it is necessary to process each component such as a lens with extremely high precision, and naturally, the equipment, the work, the inspection, etc. require a cost and man-hours, and thus the cost is high. I was in a situation where I couldn't get it.

[0004]

As a means for correcting the optical axis shift, as shown in FIG. 6A, the lens frame 20 having the lens 10 attached thereto is housed in the lens barrel 30 and then outside the lens barrel 30. From tools
A method is used in which the lens 10 is fixed by inserting 40 and applying a light shock to the embossing lens frame 20 to align the optical axes and then tightening the presser bar 50.

However, this method has many problems such that the adjustment amount of the optical axis is unstable and it takes time to repeat the work, and when dust or the like appears on the lens surface due to vibration, it is suitable for practical use. is not.

On the other hand, looking at the relationship between the lens 10 and the lens frame 20, as shown in FIG. 6B, the lens 10 is in contact with the edge portion of the lens frame 20 regardless of whether it is convex or concave. Lens 10 due to burrs on the edge, etc.
Is easily tilted and may be distorted on the lens surface when tightened by the presser bar 60.

As a result of solving these problems and improving the present invention, the adjustment of the optical axis position of the lens is easy and reliable, and the lens is mounted and supported perpendicularly to the lens barrel axis without tilting. The purpose of the invention is to provide a lens holding structure.

[0008]

In the lens holding structure for fixing a lens frame containing a lens in a lens barrel, a taper surface is formed on a part of the outer periphery of the lens frame. A lens holding structure characterized in that the optical axis position of the lens is adjusted by pressing a plurality of pairs of screw members opposed to the outer periphery of the lens barrel, and a lens having a curved surface of the lens. In a lens holding structure that is housed and fixed in a lens frame by abutting, the abutting portion of the lens frame that abuts the lens is formed with a curvature surface equivalent to the curved surface of the lens. Achieved by the retaining structure.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention is shown in FIGS.
The second embodiment is shown in FIGS.

FIG. 1 is a sectional view of a lens holding structure according to claim 1 of the present invention, and FIG. 2 is a sectional view taken along the line AA in FIG. 1, in which 1 is a part of a lens barrel, 2 is a lens frame, and 3 is a lens frame. Is a lens, and the lens 3 is housed and fixed in the lens frame 2 by a presser bar 4.

The lens barrel 1 is provided with four screw holes 1a having counterbore portions at positions equally dividing the outer peripheral surface, and the screw holes 1a have a slit as shown in FIG. Optical axis adjusting screw members 5 each having a head portion 5a fitted to the spot facing portion and a hemispherical tip portion 5b are screwed.

On the other hand, the lens frame 2 is formed with a circumferential groove 2a and a taper surface 2b connected to the circumferential groove 2a on the outer peripheral surface thereof, and an optical axis adjustment amount, which will be described later, is applied to the inner circumference of the lens barrel 1. It is fitted with a corresponding clearance.

The lens frame 2 is inserted into the inner circumference of the lens barrel 1 and
The position on the optical axis XY is determined by coming into contact with the inner butting wall 1b, and the screw members 5 are temporarily fixed in the lens barrel 1 by lightly tightening them while keeping the balance.

Next, the side wall 1c and the outer peripheral portion of the lens barrel 1 are set in the optical axis adjusting machine as a reference plane, and the respective screw members 5 are rotated to check the output of the optical axis adjusting machine while the lens frame 2 is set. The optical axis X of the lens 3 is moved by moving in the direction perpendicular to the optical axis XY.
Align Y with the axis of the lens barrel 1.

As the optical axis adjusting device, an optical decentering measuring device or a projection resolving power measuring device is used.

After the optical axes match, the screw members 5 are tightened so that the tightening forces are balanced, and the lens frame 2 is finally fixed to the lens barrel 1. At this time, each screw member 5 has its tip 5b.
Since the tapered surface of the lens frame 2 is pressed in the axial direction, the lens frame 2 is strongly pressed against the wall 1b so that the position in the optical axis XY direction is surely regulated. Further, since each screw member 5 has a hemispherical tip portion 5b, it can be sufficiently adjusted again without causing so-called galling even if it is tightly tightened. Although the structure for adjusting the optical axis of the lens frame with respect to the lens barrel has been described in the present embodiment, the present invention forms the circumferential groove and the tapered surface on the outer periphery of the lens to mount the lens on the lens frame. A structure for adjusting the optical axis can also be used.

On the other hand, FIGS. 4 and 5 show respective cross sections of the lens holding structure according to claim 2 of the present invention. In the lens 6A, the first surface is a convex surface having a curvature R1 and the second surface is a curvature R2.
And the lens 6B has a convex surface with a curvature R3 as the first surface and a convex surface with a curvature R4 as the second surface.

The lens frames 7A and 7B for accommodating the lenses 6A and 6B are provided with abutting portions 8A and 8B for abutting the concave surface having the curvature R2 and the convex surface having the curvature R4, respectively.
The lenses 6A and 6B are formed in a ring-shaped curved surface having the same curvature as the curvature R2 or the curvature R4, respectively, so that the lenses 6A and 6B can be brought into contact with each other with a slight surface.

Therefore, even if they are tightly tightened by the respective lens retainers 9A and 9B, the abutting portions 8A and 8B do not deform and each lens can be stably housed and fixed at a predetermined position. I can.

[0020]

According to the present invention, there is provided a lens holding structure capable of stably and securely fixing a single lens to a lens frame and adjusting the optical axis position of the lens with high precision by a simple operation. It will be provided.

[Brief description of drawings]

FIG. 1 is a sectional view of a lens holding structure of a first invention.

FIG. 2 is a sectional view taken along the line AA in FIG.

FIG. 3 is an external view of a screw member for adjusting an optical axis.

FIG. 4 is a cross-sectional view of a lens holding structure of a second invention.

5 is a cross-sectional view showing another embodiment of FIG.

FIG. 6A is a sectional view showing conventional optical axis adjustment, and FIGS.
FIG. 7 is a sectional view showing a conventional lens holding structure.

[Explanation of symbols]

 1 lens barrel 1a screw hole 1b abutting wall 1c side wall 2,7A, 7B mirror frame 2a circumferential groove 2b taper surface 3,6A, 6B lens 4,9A, 9B presser bar 5 screw member 5a head 5b tip 8A, 8B butting part

Claims (2)

[Claims] 1. In a lens holding structure for fixing a lens frame containing a lens in a lens barrel, a tapered surface is formed on a part of an outer circumference of the lens frame, and the tapered surface is opposed to the outer circumference of the lens barrel. The lens holding structure is characterized in that the optical axis position of the lens is adjusted by pressing with a plurality of pairs of screw members screwed together. 2. In a lens holding structure in which a lens is housed and fixed in a lens frame by abutting the curved surface of the lens, the abutting portion of the lens frame that abuts the lens is equivalent to the curved surface of the lens. A lens holding structure characterized by being formed with a curved surface.