CN101840047B - Focusing device in long-focus and heavy-caliber optical system - Google Patents

Abstract

The invention relates to a focusing device in a long focal length and large aperture optical system, relating to the technical field of optical mechanics. The invention aims to solve the problems that it is difficult to determine the coaxial precision of the optical axis of the existing focusing mechanism and other fixed mirror groups during installation, and the installation and adjustment is difficult and the focusing error is large. The device of the present invention includes an electronically controlled displacement platform and a focusing mirror group, and it also includes a slide rail seat, a shift fork and two cylinders, the focusing mirror group is arranged in the slide rail seat, and the shift fork is arranged outside the slide rail seat , the shift fork is fixedly connected with the electronically controlled displacement platform; the focusing lens group is connected with two cylinders by threads, the two ends of the shift fork are respectively provided with U-shaped grooves, and two long slot holes are opened on the slide rail seat, so The cylinder passes through the long slot hole on the slide rail seat and the U-shaped slot on the shift fork in sequence. The invention is widely used in optical systems.

Description

Focusing Device in Long Focal Length and Large Aperture Optical System

technical field

The invention relates to the field of optical machinery technology, in particular to a focusing device in an optical system.

Background technique

At present, the application environment of long focal length and large aperture optical systems is often relatively harsh, and the environment has many influences on the optical system. For example: changes in ambient temperature, changes in atmospheric pressure, system vibration, external shocks and other factors will cause the focal plane of the optical system to have a certain degree of axial offset, which will adversely affect the imaging quality of the system. The existing focusing mechanism is shown in Figure 1. The focusing mechanism is mainly composed of a focusing lens group and a high-precision electronically controlled mobile platform. The coaxial accuracy of the shaft is difficult to guarantee, the installation and adjustment are difficult, and the focusing error is large; the cost of the high-precision electronically controlled mobile platform is relatively high. In order to ensure the imaging quality of the optical system, it is necessary to adjust the axial position of the optical components in the optical system so as to reversely correct the defocus of the focal plane of the system.

Contents of the invention

In order to solve the problems that the existing focusing mechanism is difficult to determine the coaxial accuracy of the optical axis of other fixed mirror groups during installation, the installation and adjustment is difficult, and the focusing error is large, the present invention provides a long focal length, large aperture optical system. the focusing device.

The device of the present invention includes an electronically controlled displacement platform and a focusing mirror group, and it also includes a slide rail seat, a shift fork and two cylinders, the focusing mirror group is arranged in the slide rail seat, and the shift fork is arranged on the slide rail seat On the outside, the shift fork is fixedly connected with the electronically controlled displacement platform; the focusing lens group is connected with two cylinders by threads, the two ends of the shift fork are respectively provided with U-shaped grooves, and two long slot holes are opened on the slide rail seat. The cylinder passes through the long slot hole on the slide rail seat and the U-shaped groove on the shift fork in turn; the slide rail seat and the fixed lens seat in the optical system are designed to be integrated, so that the center of the round hole of the slide rail seat and the fixed lens seat The center of the round hole is coaxial with high precision.

Principle of the present invention: the present invention integrates the design of the seat of the fixed lens in the slide rail seat and the optical system, so that the center of the round hole of the slide rail seat (the round hole for placing the focusing lens group) and the center of the round hole of the fixed lens seat High-precision coaxial; the cylinder set on the focusing lens group is moved by the fork, so that the focusing lens group moves back and forth along the axis of the slide rail seat; the gap between the focusing lens group and the slide rail seat is within 3- Between 5 microns, so as to achieve high-precision coaxiality of the optical axis during the focusing process; there will be no error in the optical axis shaking of the focusing lens group; at the same time, a long slot hole is opened on the slide rail seat, and the long slot The length range of the hole is the focusing range of the focusing lens group. There is a U-shaped groove on the shift fork. The width of the U-shaped groove is precisely matched with the size of the outer circle of the cylinder. When the shift fork is moved, there will be no focus The error of the optical axis movement of the mirror group and the empty return; the shift fork is installed on the electronically controlled displacement platform, thus realizing the design of the focusing device in the long focal length and large aperture optical system.

Beneficial effects of the present invention: the focusing device described in the present invention is simple in structure, easy to install and adjust, and the slide rail seat and the non-moving lens seat are designed as one body, and the focusing precision is high.

Description of drawings

Fig. 1 is a structural schematic diagram of an existing focusing device;

Fig. 2 is a schematic diagram of the positional relationship between the slide rail seat and the focusing lens group in the present invention;

Fig. 3 is the structural representation of device of the present invention;

Fig. 4 is a schematic diagram of the connection relationship between the focusing lens group and the cylinder in the present invention;

Fig. 5 is a schematic structural view of the slide rail seat in the present invention;

Fig. 6 is a schematic diagram of the structure of the shift fork in the present invention.

In the figure: 1. Electronically controlled displacement platform, 2. Focusing lens group, 3. Slide rail seat, 3-1. Long slot hole, 4. Shift fork, 4-1. U-shaped groove, 5. Column.

Detailed ways

Specific Embodiment 1: This embodiment is described in conjunction with Fig. 2 to Fig. 6, the focusing device in the optical system with long focal length and large aperture includes an electronically controlled displacement platform 1 and a focusing mirror group 2, and it also includes a slide rail seat 3, A shift fork 4 and two cylinders 5, the focusing lens group 2 is arranged in the slide rail seat 3, the shift fork 4 is arranged on the outside of the slide rail seat 3, and the shift fork 4 is fixedly connected with the electric control displacement platform 1; The focusing lens group 2 and the two cylinders 5 are threadedly connected, the two ends of the shift fork 4 are respectively provided with U-shaped grooves 4-1, and the slide rail seat 3 is provided with two long slot holes 3-1, and the cylinders 5 Sequentially pass through the slotted hole 3-1 on the slide rail seat 3 and the U-shaped groove 4-1 on the shift fork 4; the slide rail seat 3 and the fixed lens seat in the optical system are designed to be integrated, so that the The center of the round hole is coaxial with the center of the round hole of the fixed lens seat with high precision.

The precision of the electronically controlled displacement platform 1 in this embodiment is not limited.

The two slotted holes 3 - 1 on the slide rail seat 3 described in this embodiment are symmetrically distributed on the circumferential surface of the slide rail seat 3 at an interval of 180 degrees.

The gap between the mating surfaces of the focusing lens group 2 and the slide rail seat 3 in this embodiment is between 3-5 microns.

In this embodiment, the width of the long slot hole 3-1 on the slide rail seat 3 is precisely matched with the diameter of the outer circle of the cylinder 5, and the matching gap is less than 0.01 mm.

The length range of the slot hole 3 - 1 on the slide rail seat 3 in this embodiment is the same as the focusing range of the focusing lens group 2 .

In this embodiment, the U-shaped groove 4-1 on the shift fork 4 is precisely matched with the outer diameter of the cylinder 5, and the matching gap is less than 0.01 mm.

Claims (5)

1. the focus control in long-focus, the heavy-caliber optical system, comprise automatically controlled displacement platform (1) and focusing lens group (2), it is characterized in that, it also comprises slide track seat (3), shift fork (4) and two cylinders (5), described focusing lens group (2) is arranged in the slide track seat (3), shift fork (4) is arranged on the outside of slide track seat (3), and shift fork (4) is fixedlyed connected with automatically controlled displacement platform (1); Described focusing lens group (2) adopts with two cylinders (5) and is threaded, the two ends of shift fork (4) are respectively equipped with U type groove (4-1), have two long slot bores (3-1) on the slide track seat (3), described cylinder (5) passes the U type groove (4-1) on long slot bore (3-1) and the shift fork (4) on the slide track seat (3) successively; The design of fixed lens seat is made of one in slide track seat (3) and the optical system, makes the circular hole center of slide track seat (3) coaxial with the circular hole height of center precision of fixed lens seat.

2. the focus control in long-focus according to claim 1, the heavy-caliber optical system is characterized in that, the width of the long slot bore (3-1) on the described slide track seat (3) and the outside diameter precision-fit of cylinder (5), and tolerance clearance is less than 0.01mm.

3. the focus control of long-focus according to claim 1, heavy-caliber optical system is characterized in that, the length range of the slotted eye (3-1) on the described slide track seat (3) is identical with the focusing range of focusing lens group (2).

4. the focus control of long-focus according to claim 1, heavy-caliber optical system is characterized in that, U type groove (4-1) width on the described shift fork (4) and the outside diameter precision-fit of cylinder (5), and tolerance clearance is less than 0.01mm.

5. the focus control of long-focus according to claim 1, heavy-caliber optical system is characterized in that, the mating surface gap of described focusing lens group (2) and slide track seat (3) is between the 3-5 micron.

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