KR100282532B1 - Night vision relay optical system - Google Patents

Abstract

A visual relay optical system employing a holographic lens is disclosed.

This visual relay optical system is disposed on the optical axis between the visual amplification tube (IIT) and the camera, and is sequentially arranged from the image amplification tube side so that the image formed on the upper surface of the image amplification tube can be transmitted to the camera. A first lens of; A second lens having a convex entrance surface and an exit surface having a hologram pattern formed thereon; A biconvex third lens; A fourth lens of calico; It is characterized by consisting of five lenses including a biconvex fifth lens.

Description

Night vision relay optical system

The present invention relates to a night vision relay optical system, and more particularly, to a night vision relay optical system employing a holographic lens.

In general, goggles or night vision in the form of attachment to a helmet is used to identify or photograph objects at night using infrared light. To this end, the night vision mirror is provided with an imaging intensifying tube (Amaging Intensifying Tube) for amplifying light with an optical device, a camera having an upper image forming image, and a phosphorescent upper surface formed between the image amplifier and the camera. Relay optical system for transmitting to the camera.

1 is a schematic diagram illustrating an optical arrangement of a conventional night vision relay optical system.

As shown, the night vision relay optical system includes seven lens units and an aperture stop. In the figure, F1 represents the top surface (Phosphore surface) of the image amplification tube, F2 represents the top surface of the camera. The lens unit includes two positive meniscus lenses (L1) (L3), two biconvex lenses (L2) (L4), one biconvex lens (L5), and two sheets Is made up of the flat convex lenses L6 and L7. Further, an aperture A is further provided on the optical path between the biconvex lens L5 and the flat convex lens L6. As described above, the conventional relay optical system has a Modulation Transfer Function (MTF) of 0.80 / 10 lps on the optical axis, an MTF of 0.45 / 10 lps on the peripheral image, and has a distortion performance of about 5%. .

As described above, the configured relay optical system does not have a big problem in its optical performance, but has a disadvantage in that the optical arrangement is difficult and the manufacturing cost is high because it is composed of seven lens units.

Accordingly, an object of the present invention is to provide a night vision relay optical system capable of reducing assembly number and cost by reducing the number of lenses.

1 is a schematic diagram showing an optical arrangement of a conventional night vision relay optical system.

Figure 2 is a schematic diagram showing the optical arrangement of the optical relay optical system according to an embodiment of the present invention.

3 shows a theoretical hologram profile of a portion of a second lens according to an embodiment of the invention.

4 shows an actual hologram profile of a portion of a second lens according to an embodiment of the invention.

<Description of the code | symbol about the principal part of drawing>

1.Top of image amplification tube 3 ... Top of camera 11 ... First lens

12 ... second lens 13 ... third lens 14 ... fourth lens

15 ... Fifth Lens 20 ... Aperture

In order to achieve the above object, the present invention is disposed on the optical axis between the night vision amplifier (IIT) and the camera, in the relay optical system for vision for transmitting the image formed on the upper surface of the video amplifier tube to the camera, A biconvex first lens sequentially from the image amplifying tube; A second lens having a convex entrance surface and an exit surface having a hologram pattern formed thereon; A biconvex third lens; A fourth lens of calico; It characterized in that it comprises a biconvex fifth lens.

Hereinafter, a relay optical system according to an exemplary embodiment of the present invention will be described in detail with reference to the accompanying drawings and tables.

Figure 2 is a block diagram showing the optical arrangement of the optical relay optical system according to the present invention.

As shown in the drawing, the first lens 11 to the fifth lens 15 are sequentially disposed toward the camera 3 from the IIT 1 and the second lens. The emission surface of (12) is characterized in that a hologram pattern is formed.

The first lens 11 is disposed adjacent to the image surface of the IIT 1 and is a biconvex lens designed to reduce the degree of divergence of an image incident from the IIT 1. The second lens 12 is a flat convex lens having a convex entrance surface and a plane exit surface, and a hologram pattern is formed on the exit surface. The second lens 12 reduces the degree of divergence of the image passing through the first lens 11. The third lens 13 and the fourth lens 14 are disposed adjacent to each other, the third lens 13 is a biconvex lens, and the fourth lens 14 is a biconcave lens. That is, the exit surface of the third lens 13 and the entrance surface of the fourth lens 14 have the same curvature. The third lens 13 converges the image passing through the first and second lenses 11 and 12, and the fourth lens 14 corrects the aberration of the image passing through the first to third lenses. do. The fifth lens 15 is a biconvex lens that converges the image transmitted through the first to fourth lenses so as to be formed on the image surface 3 of the camera.

Preferably, the diaphragm 20 is further provided between the fourth lens 14 and the fifth lens 15. The diaphragm 20 blocks an incident image incident on the IIT upper surface 1 side.

, 인접한 렌즈면 사이의 광축상의 거리들 및, 렌즈의 재료의 일 데이터를 표1에 나타내었다.A radius of curvature and an effective opening radius of each lens and an image surface of the relay optical system;

Table 1 shows the distances on the optical axis between adjacent lens surfaces and the material of the lens material.

(i = 1, 2, 3, ... 10)로 정의된다. 여기서, R_i는 렌즈 각 면의 곡률반경이고, Y_i는 각 렌즈면의 높이를 말한다.Where SAG =

(i = 1, 2, 3, ... 10) Here, R _i is the radius of curvature of each lens surface, Y _i is the height of each lens surface.

The emission surface of the second lens, that is, the R4 surface, is a hologram surface, and a hologram pattern as shown in FIGS. 3 and 4 is formed, and the data are shown in Table 2. FIG. 3 shows a profile of a theoretical hologram pattern, and FIG. 4 shows an actual profile, that is, a profile quantized to eight levels. That is, the height of the theoretical profile of the hologram pattern is 0.709 mu m, and the total height of the profile quantized to eight levels is 0.620 mu m. Then, 19 profiles as described above are gathered to form an exit surface of the second lens. The hologram pattern as described above obtains a fine shape by a dry etching method using an ion beam.

The visual relay optical system according to the present invention, configured as described above, has a Modulation Transfer Function (MTF) of 0.81 / 10 lps on its axis, 0.6 / 10 lps of MTF on the peripheral upper surface, and a distortion aberration. It has about 5% optical performance.

Therefore, the visual relay optical system according to the present invention has excellent optical performance as compared with the relay optical system implemented with the conventional seven-lens lens and implemented by five lenses, so that the installation of the optical system is easy, and the optical system Not only can the overall weight be reduced, but manufacturing costs can be greatly reduced. Therefore, it is very useful when applied to the device which requires small size and light weight such as goggles night view or HMD.

Claims (4)

In the visual relay optical system disposed on the optical axis between the visual amplification tube (IIT) and the camera, and transmits the image formed on the upper surface of the image amplifier tube to the camera, Sequentially arranged from the image amplifying tube side, A biconvex first lens; A second lens having a convex entrance surface and an exit surface having a hologram pattern formed thereon; A biconvex third lens; A fourth lens of calico; The visual relay optical system comprising a five-piece lens including a biconvex fifth lens. The visual relay optical system of claim 1, further comprising an aperture between the fourth lens and the fifth lens to limit a passing area of an image to be transmitted. The optical relay optical system of claim 2, wherein each of the first to fifth lenses and the aperture satisfy Table 1 below. TABLE 1

The relay optical system according to claim 1 or 2, wherein the emission surface of the second lens satisfies Table 2 below. TABLE 2

Images