JPH0513027A - Noctovision - Google Patents

Abstract

PURPOSE:To form the best-quality image that is already focused on every target- body in a field of vision. CONSTITUTION:As for a long-distance target body 1 in a field of vision, its best-quality image is formed at a position near the focal distance of an object lens 3 from a position at the principal point of the object lens 3. As for also a short-distance target body 2, its best-quality image is formed at a position distant from the focal distance of the object lens 3. A substrate 7 for entering subsidiary light into a photoelectric surface, made up of an optical fiber and having its cross-sectionally wedge-shaped specified inclination, is attached to a substrate 41 for entering light into the photoelectric surface of an image intensifier tube 4, so that the best-quality image that can secure focal conformity with any target-body of every distance in the field of vision may be obtained.

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 which enables visual recognition while focusing from a short distance to a long distance in a visual field.

[0002]

2. Description of the Related Art A conventional night-vision device has a structure as shown in FIG. Light from the long-distance target object 1 and the short-distance target object 2 which are illuminated by weak light such as starlight is collected by the objective lens 3 and is focused on the photocathode light incident substrate 41 of the image intensifier tube 4 to form an image. It is amplified by the intensifier tube 4 and displayed on the phosphor screen 42. This image is magnified by the eyepiece 5 and visually recognized by the eye 6.

[0003]

In the conventional night-vision device described above, the optical axis of the objective lens 3 and the optical axis of the image intensifier tube 4 coincide with each other as shown in FIG. Since the photocathode 42 of No. 4 and the photocathode light incident substrate 41 are perpendicular to the optical axis of the objective lens 3, only the target object at a certain distance in the field of view is focused, and the target objects at other distances are focused. However, there is a drawback in that the focus shifts and the focus shifts, so-called defocusing occurs.

An object of the present invention is to eliminate the above-mentioned drawbacks and to provide a night-vision device in which defocusing with respect to all target objects included in the visual field is significantly suppressed.

[0005]

SUMMARY OF THE INVENTION A night-vision device of the present invention comprises an objective lens for forming an image of a target object under low light and an image intensifier tube for electrically amplifying the image and displaying it on a fluorescent screen. And a night-vision device comprising an eyepiece that magnifies the image displayed on the fluorescent screen, in the surface of the photocathode light input substrate as the light-receiving surface of the image intensifier tube, a short distance within the field of view. The light receiving side of the target object is thin, and the light receiving side of the long-distance target object in the field of view has a thicker wedge-shaped cross section. It has a structure in which a substrate is attached.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of a night-vision device according to an embodiment of the present invention.

The night-vision device shown in FIG. 1 has the same objective lens 3 and image intensifier tube 4 as those shown in FIG.
In addition to the eyepiece lens 5, the present invention is directly related to the present invention and includes a tilted photocathode sub-light incident substrate 7 made of an optical fiber.

The objective lens 3 forms an image of the long-distance target object 1 or the short-distance target object 2 to obtain an image. The image intensifier tube 4 is for electrically amplifying the image formed by the objective lens 3 and displaying it on the fluorescent screen 42, and the eyepiece 5 is displayed on the fluorescent screen 42. This is to enlarge the increase so that it can be visually recognized by the eye 6.

On the photocathode light incident substrate 41 of the image intensifier tube 4, a sub-light incident substrate 7 made of an optical fiber and having a wedge-shaped cross section is attached.

In this way, the long-distance target object 1 in the field of view is the best image in which the defocus is remarkably suppressed from the position of the principal point of the objective lens 3 to the focal length f of the objective lens 3. It is imaged.

Further, the long-distance target object 2 in the field of view has the best image formed at a position farther from the principal point of the objective lens 3 than the focal length f of the objective lens 3.

Therefore, by attaching the inclined photocathode sub-light incidence substrate 7 made of an optical fiber to the photocathode light incidence substrate 41 of the image intensifier tube 4, any target object at any distance within the field of view can be obtained. The best image is formed.

For example, assuming a case of viewing within the range of 5 to 50 m, if the focal length of the objective lens is 50 mm and the effective diameter of the photocathode light incident substrate 41 of the image intensifier tube 4 is 25 mm, then 50 m ahead. Long-distance target object 1
Forms the best image at a position of about 50.25 mm from the principal point of the objective lens 3, and the short-range target object 2 located 5 m ahead is at a position of about 50.505 mm from the principal point of the objective lens 3. Form the best image.

In this case, if the inclination θ of the photocathode sub-light incident substrate having an inclination made of an optical fiber is set to about 1 ° 5 minutes, an image with less out-of-focus can be obtained for all target objects in the visual field. .

[0016]

As described above, according to the present invention, a wedge-shaped photocathode sub-light entrance substrate made of an optical fiber and having a cross-section inclined so as to match the focal points of all targets in the field of view is used. Adhesion to the above has an effect of obtaining an image in which defocus is significantly suppressed from a short distance to a long distance in the visual field of the night vision device.

[Brief description of drawings]

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

FIG. 2 is a configuration diagram of a conventional night-vision device.

[Explanation of symbols]

 1 Long-distance Target Object 2 Near-distance Target Object 3 Objective Lens 4 Image Intensifier Tube 5 Eyepiece 6 Eye 7 Photoelectric Surface Sub-light Incident Substrate 41 Photoelectric Surface Light Incident Substrate 42 Fluorescent Surface

Claims (1)

Claim: What is claimed is: 1. An objective lens for forming an image of a target object under low light, an image intensifier tube for electrically amplifying the formed image and displaying the image on a fluorescent screen, and In a night-vision device comprising an eyepiece that magnifies the displayed image,
On the surface of the photocathode light input substrate serving as the light receiving surface of the image intensifier tube, a wedge-shaped cross section in which the light receiving side of the short-range target object in the field of view is thin and the light receiving side of the long-range target object in the field of view is thick A night-vision device, comprising: a photocathode sub-light incidence substrate of an optical fiber, which has substantially the same focus for all target objects in the field of view.