JPH04350607A - Lens barrel structure - Google Patents

Abstract

PURPOSE:To reduce component machining and adjusting operation in assembly, to reduce the cost, and to enable mold correction and prevent optical aberrations from deteriorating by providing a total reflecting mirror between a front and a rear group, setting the optical axis of the rear group at a certain angle to the optical axis of the front group, and providing a means which adjusts the angle. CONSTITUTION:A lens barrel 1 is in an L shape and provided with a rib 4 as the means for adjusting the angle at a refraction part, and the sizes (a) and (b) of the rib 4 are corrected when a mold is manufactured. The total reflecting mirror 2 which bends the optical axis by 90 is fitted to the refraction part of the lens barrel 1 at 45 with a mirror presser 3. Thus, the rib 4 is provided on the refraction part of the bent lens barrel 1 and its thickness and size are varied to improve the right-angle accuracy between the front group and rear group. Further, lens fitting in each group is performed in one direction to improve the coaxial accuracy and simplify the mold. Further, plane barrel fitting is employed for the lenses to correct the mold and improve the inclination accuracy.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens barrel structure, and more particularly to a folded lens barrel.

0002

2. Description of the Related Art Conventional folding lens barrels are known as camera angle finders, submarine periscopes, etc. that refract two independent optical systems to change the magnification or field of view.

0003

[Problems to be Solved by the Invention] However, in the above conventional system, two independent optical systems are used to change the field of view, and the structure consists of three parts: a front group, a refracting section, and a rear group.
Since the optical axis was adjusted using a reflective mirror in the refracting section, there was a problem in that it took a long time to make adjustments during parts processing and assembly, which increased costs.

Furthermore, in the refracting section, if the direction of the die is different and the front group and the rear group are assembled and the precision is poor, the shape cannot be corrected, so there may be problems with tilt or coaxiality. There is a problem in that the accuracy decreases and becomes a factor that deteriorates optical aberrations. The present invention aims to solve the above problems. That is, the present invention can reduce the adjustment work in parts processing and assembly, thereby reducing costs, and also enables mold correction in the case of poor assembly accuracy, thereby preventing deterioration of optical aberrations. The purpose of this is to provide a lens barrel structure that allows for

[0005]

[Means for Solving the Problems] In order to achieve the above object, the lens barrel structure of the present invention is an optical system composed of a front group and a rear group separated by a large air gap. It is a molded lens that has a total reflection mirror between the groups, and the optical axis of the rear group is oriented at a certain angle with respect to the optical axis of the front group. The bending section is provided with a means for adjusting the angle.

[0006]

[Function] According to the present invention, the lens is formed of a molded part in which the optical axis of the rear group is oriented at a certain angle with respect to the optical axis of the front group, and the refractive parts of the front group and the rear group are arranged at an angle. Since the adjustment means is provided, adjustment work during parts processing and assembly is reduced, and angle adjustment is also performed with high precision.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a sectional view showing one embodiment of the present invention, and FIG. 2 is a perspective view thereof.

In FIGS. 1 and 2, reference numeral 1 denotes a lens barrel, which has an L-shape (mold part), and is provided with a rib 4 as a means for adjusting the angle at the refractive part.
The dimensions a and b of are corrected. 2 is the optical axis 9
It is a total reflection mirror bent at 0°, and is attached to the refractive part of the lens barrel 1 at an angle of 45° with a mirror holder 3.

[0009] Also, G1, G2, G3, G4, G5, G
6 and G7 are lens groups each consisting of one or more optical lenses. Furthermore, 5 and 6 are the lenses G
3. This is the flat body attachment part when installing G5.

Here, in the folding lens barrel shown in FIG. 1, parts A and B near the total reflection mirror 2 are
Because the light passes through the lens barrel without going through the light, it tends to become ghost light.
As shown in an enlarged view in FIG. 3, a light shielding line is inserted to prevent ghosts.

[0011] The parts A and B near the total reflection mirror 2 have the same shape, and the lenses G1 to G7 each consist of one or more optical lenses, as described above, and their lens holders are is used as a C-ring holder.

As described above, by providing the ribs 4 at the bending portion of the bent lens barrel 1 and changing the thickness and dimensions, it is possible to improve the orthogonality accuracy between the front group and the rear group. Furthermore, by mounting the lens barrel in one direction within each group, it is possible to improve the accuracy of coaxiality and simplify the mold. Furthermore, the lens barrel is a flat barrel, which enables shape correction and improves tilt accuracy.

[0013] Due to the above, manufacturing errors in optical performance are small, and the adjustment mechanism for the reflection mirror 2 in the refracting section can be omitted. Therefore, the lens barrel 1 shown in FIG. 1 can be used as a projection device for projecting an image. If used for this purpose, the size of the device can be kept small.

[0014]

[Effects of the Invention] As explained above, according to the present invention,
Consisting of a single molded lens with the optical axis of the rear group at a certain angle relative to the optical axis of the front group, adjustment work during parts processing and assembly is significantly reduced, leading to cost reductions. . Furthermore, since the refracting portions of the front group and the rear group have means for adjusting the angle, the angle can be adjusted with high precision. Therefore, in the case of poor assembly accuracy, mold correction is possible, and deterioration of optical aberrations can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a perspective view of FIG. 1;

FIG. 3 is an enlarged cross-sectional view of a part of FIG. 1;

[Explanation of symbols]

1...Lens barrel
2... Total reflection mirror 3... Mirror holder
4...Ribs 5, 6...Flat body attachment part
G1 to G7...lens group

Claims (3)

[Claims] Claim 1: An optical system consisting of a front group and a rear group separated by a large air gap, which has a total reflection mirror between the front group and the rear group, and has a total reflection mirror along the optical axis of the front group. On the other hand, it consists of a molded lens that is configured with the optical axis of the rear group at a certain angle.
Moreover, the lens barrel structure is characterized in that the refracting portions of the front group and the rear group include means for adjusting the angle. 2. The lens barrel structure according to claim 1, wherein the diameters of the barrel portions of the optical systems of the front group and the rear group gradually increase from the side closer to the total reflection mirror toward the outside. 3. The lens barrel structure according to claim 1, wherein the barrel attachment portion of at least one optical system group is a flat barrel attachment.