JPH07104195A - Night viewer - Google Patents

Abstract

PURPOSE:To provide the night viewer capable of simultaneously outputting images of less out-of-focus to target objects existing at different distances. CONSTITUTION:This night viewer has an objective lens 1 for forming the images of the target objects, an image intensifier 2 for receiving the formed light images and electrically amplifying and displaying the images and an eyepiece lens 3 for magnifying the outputted images. The photodetecting surface of the image intensifier 2 is provided with a stepped light incident substrate 22 changed stepwise in thickness in a direction orthogonal with the optical axis. The target object 5 of a relatively short distance is focused in the thin part of the stepped light incident substrate 23 and the target object 4 of a relatively remote distance is focused in the thick part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a night-vision device, and more particularly to a night-vision device capable of simultaneously visually recognizing target objects having different distances within a visual field.

[0002]

2. Description of the Related Art A schematic structure of a conventional night vision device is shown in FIG. The main components of the night-vision device are an objective lens 1, an image intensifier (or an image intensifier) 2,
And the eyepiece 3. The objective lens 1 is a target object 4
The weak light from the light sources 5 and 5 is condensed to form an object image on the photocathode incidence substrate 21 of the image intensifier 2. The image intensifier 2 electrically amplifies the feeble light image received by the photocathode incidence substrate 21 and displays it on the fluorescent screen 22 as a bright image. This bright output image is magnified by the eyepiece 3 and visually recognized by the naked eye 6. The function of the image intensifier 2 enables the naked eye 6 to visually recognize the target object 4 or 5 illuminated by weak light such as starlight.

[0003]

However, in the above-mentioned conventional night-vision device, in order to make the optical axes of the objective lens 1 and the image intensifier 2 coincide with each other, the incident surface of the photocathode incidence substrate 21 is set to the objective lens 1. It is installed so that it is perpendicular to the optical axis. For this reason, there is a problem in that only a target object at a predetermined distance within the field of view is focused and images of objects at other distances are out of focus.

As a means for solving such a problem,
A night vision device has been proposed in which the surface of the photocathode incidence substrate has an inclination (Japanese Patent Laid-Open No. 63-148224). This makes it possible to obtain an image with little out-of-focus from a short distance to a long distance.

It is an object of the present invention to provide a night-vision device capable of simultaneously outputting images with little out-of-focus on target objects at different distances.

[0006]

A night vision device according to the present invention has a light receiving surface of an image intensifier which receives a formed light image, electrically amplifies and displays the light image, in a direction perpendicular to the optical axis. It is characterized in that a light-incident substrate with a step having a stepped shape is provided.

[0007]

The target object at a relatively short distance is focused on the thin portion of the light incident substrate with steps, and the target object at a relatively long distance is focused on the thick portion.

[0008]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic diagram showing an embodiment of a night vision device according to the present invention, and FIG. 2 is a perspective view of a light incident substrate with steps in this embodiment.

As shown in FIG. 1, the main components as a night vision device are an objective lens 1, an image intensifier 2 and an eyepiece lens 3. In the present embodiment, the image intensifier 2 is further added. The light incident substrate 23 with a step is attached on the photoelectric surface incident substrate 21.
The light image received through the stepped light incident substrate 23 is electrically amplified by the image intensifier 2,
A bright image is displayed on the fluorescent screen 22.

As shown in FIG. 2, the stepped light incident substrate 23 is formed of a bundle of optical fibers 231 and has a step on the light incident side. That is, the thick portion 232 is composed of a long optical fiber bundle, and the thin portion 233 is composed of a short optical fiber bundle. The size of this step difference is determined by the distance between the target objects 4 and 5 to be focused, as described below.

The objective lens 1 focuses weak light from the target objects 4 and 5 and forms an object image on the stepped light incident substrate 23 of the image intensifier 2. that time,
The target object 4 at a long distance forms the best image at a position close to the focal length of the objective lens 1, and the target object 5 at a short distance forms a best image at a position far from the focal length of the objective lens 1.
Therefore, if the surface of the thick portion 232 of the stepped light incident substrate 23 is arranged at the focal position of the objective lens 1, the thick portion 2
The best image of the long-distance target object 4 can be simultaneously captured by 32, and the best image of the short-distance target object 4 can be simultaneously captured by the thin portion 233 in the image intensifier 2. Therefore, target objects with different distances can be less out of focus. The images can be viewed simultaneously.

Next, a concrete example of setting the steps of the light incident substrate 23 with steps will be described. The objective lens 1 has a focal length of 25 m
m, the distance of the long-distance target object 4 from the principal point of the objective lens 1 is 5 m, and the distance of the short-distance target object 5 is 30 cm. Under such a condition, the image of the long-distance target object 4 is formed at a position of 25.1256 mm from the principal point of the objective lens 1, that is, in the vicinity of the focal point, and the image of the short-distance target object 5 is farther from the focal position. The image is formed at a position of 0.2727 mm.

Therefore, if the step of the stepped light incident substrate 23 is set to 2.1471 mm and the surface of the thick portion 232 is arranged at the focal position of the objective lens 1, the best image formation of the long-distance target object 4 5 m ahead is achieved. Through thick section 232 to 30c
The best image of the short-distance target object 5 at a distance of m
Through the image intensifier 2 at the same time, and images with less out-of-focus images of the target objects 4 and 5 can be obtained.

[0015]

As described above, the night-vision apparatus according to the present invention is provided with the stepped light-incident substrate having a stepwise change in thickness on the light-receiving surface of the image intensifier. It is possible to capture an in-focus image of an object at the same time and obtain a night-vision image with little out-of-focus.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of a night vision device according to the present invention.

FIG. 2 is a perspective view of a light incident substrate with steps in the present embodiment.

FIG. 3 is a schematic configuration diagram showing an example of a conventional night-vision device.

[Explanation of symbols]

 1 Objective Lens 2 Image Intensifier 3 Eyepiece 4 Long Distance Target Object 5 Near Distance Target Object 21 Photoelectric Surface Incident Substrate 22 Fluorescent Surface 23 Stepped Light Incident Substrate 231 Optical Fiber 232 Thin Part 233 Thick Part

Claims (3)

[Claims] 1. An objective lens system for forming an image of a target object, an image intensifier for receiving the formed optical image and electrically amplifying and displaying the image, and an eyepiece for enlarging the output image. In a night-vision device having a lens system, a dark-incidence substrate having a stepped light-incident substrate having a stepwise change in thickness in a direction orthogonal to an optical axis is provided on a light-receiving surface of the image intensifier. Vision device. 2. The night-vision apparatus according to claim 1, wherein the light-incident substrate with steps comprises a bundle of optical fibers having an optical axis that coincides with the optical axis direction. 3. The night-vision apparatus according to claim 1, wherein a surface of a thick portion of the stepped light input substrate is arranged at a focal position of the objective lens system.