JPH09197292A - Head part of pipe camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the head part of the pipe camera which need not be increased in the number of components so much, makes it easy to obtain airtightness, and prevents light from traveling around. SOLUTION: A CCD camera 11 is arranged at the center part in a housing 1 and a light source 10 for lighting is arranged at the periphery of this CCD camera 11; and a glass plate 3 for airtight holding is held atop of the housing 1 in front of the CCD camera 11 and the light source 10 for lighting at the periphery of the CCD camera 11 is arranged nearby the glass plate 3 for airtight holding. Further, a glass plate 4 which has a lower refractive index than the glass plate 3 for airtight holding is arranged on the inner peripheral side of the light source 10 for lighting in contact with the glass plate 3 for airtight holding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION Various pipe cameras have been proposed in the past. The basic structure of the head is as shown in FIG. This includes a light guide 10 (in the present invention, which emits light like a light guide, an end portion thereof is also referred to as a light source for illumination) in a cylindrical housing 1, and an observation device 2 such as a CCD camera 11 is built therein. A disk-shaped glass plate 31 for maintaining airtightness is arranged in front of these observation devices 2. In the case of the head of this structure, a part of the light emitted from the light guide 10 is reflected by the glass plate 31 for maintaining the airtightness provided at the front side, and so-called light wraparound enters the CCD camera 11, so that the CCD camera. There is a problem that the image picked up at 11 is deteriorated.

As a means for solving this problem, a head of a pipe camera shown in FIG. 4 has been proposed. This head is
A ring-shaped outer glass plate 41 is arranged ahead of the observation device 2, an inner glass body 42 is arranged concentrically inside the outer glass plate 41, and between the outer glass plate 41 and the inner glass body 42. Further, a metallic ring-shaped support tool 43 for supporting the inner peripheral edge of the outer glass plate 41 and the outer peripheral edge of the inner glass body 42 is arranged.

[0003]

A ring-shaped support tool 43 is provided.
By providing the glass plate 31 of FIG. 3 with the outside glass plate 41 of the light guide 10 for illumination and the CCD camera 1.
The inner glass body 42 for 1 is divided into the light guide 1
This prevents a part of the light emitted from 0 from entering the CCD camera 11. However, this head not only increases the number of parts and increases the cost, but also the ring-shaped support tool 43, the outer glass plate 41, and the inner glass body 42.
There is a problem that it becomes difficult to keep the airtightness.

The present invention solves the above-mentioned problems, makes it easy to keep airtight without increasing the number of parts so much,
It is an object of the present invention to provide a pipe camera head capable of preventing light from wrapping around.

[0005]

The present invention has the following means to solve the above problems.

In the head of the pipe camera of the present invention, a CCD camera is arranged in the center of the housing, an illumination light source is arranged around the CCD camera, and a glass plate for maintaining airtightness is provided in front of the CCD camera. In the head of the pipe camera, which is held at the tip of the housing, the light source for illumination around the CCD camera is arranged close to the glass plate for maintaining airtightness, and the light source for illumination has the above-mentioned inner peripheral side. It is characterized in that a glass plate having a lower refractive index than the glass plate for maintaining airtightness is arranged in a state of being in close contact with the glass plate for maintaining airtightness.

According to the head of the pipe camera of the present invention, C
By arranging a glass plate having a lower refractive index than the glass plate in close contact with the inside of the glass plate for maintaining airtightness provided in front of the CD camera, a part of the light emitted from the illumination light source is a glass plate. Even if it is reflected by, it will not enter the CCD camera because it is reflected again by the glass plate having a low refractive index inside the glass plate. Further, according to the head of the pipe camera of the present invention, the glass plate for maintaining the airtightness provided on the front side of the CCD camera is integral, and it is particularly difficult to hold the glass plate airtightly at the tip of the housing. Not a thing. Further, since the glass plate having a low refractive index is simply placed inside the glass plate so as to be in close contact with the glass plate, the number of parts is increased and the cost is not increased particularly.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION An example of an embodiment of the head of a pipe camera of the present invention will be described in more detail below with reference to FIG. In FIG. 1, reference numeral 1 is a metal casing of a pipe camera, and 2 is an observation device. The observation device 2 includes a light guide 10 for optical transmission and a CCD camera 11 for imaging.
Consists of

Reference numeral 3 in FIG. 1 denotes a disk-shaped outer glass plate attached to the front end of the housing 1 for keeping airtightness, and 4 denotes a concentric circle inside the outer glass plate 3 for preventing light from wrapping around. It is a disk-shaped inner glass plate. The inner glass plate 4 has a lower refractive index than the outer glass plate 3. Outside glass plate 3
As shown in FIG. 1, the outer peripheral surface thereof is airtightly adhered and fixed to the inner peripheral surface of the cylindrical casing 1 with an adhesive. The outer glass plate 3 and the inner glass plate 4 are firmly fixed to each other with an optical adhesive. A predetermined number of light guides 10 are arranged on the outer periphery of the inner glass plate 4 in a state in which the tip portion of the light guide 10 is close to the inner surface of the outer glass plate 3.

A case where light is emitted from the tip of the light guide 10 in the head of the pipe camera constructed as described above will be described with reference to FIG. Part of the light emitted from the tip of the light guide 10 passes through the optical path of A0 and is partly reflected by the surface of the outer glass plate 3 to form A1.
And is returned to the inside of the outer glass plate 3. A part of the light passing through the optical path A1 is reflected at the boundary between the outer glass plate 3 and the inner glass plate 4. The light that is not reflected at the boundary between the outer glass plate 3 and the inner glass plate 4 enters the inner glass plate 4 along the optical path A2. The light incident on the inner glass plate 4 through the optical path A2 is reflected by the surface of the inner glass plate 4 and returned to the inside of the inner glass plate 4 so as not to enter the CCD camera 11. Although the light guide is used as the illumination light source in the above embodiment, the illumination light source is not limited to the light guide and may be a well-known illumination lamp.

[0011]

As described above, according to the head of the pipe camera of the present invention, the glass plate having a lower refractive index than the glass plate inside the airtightness maintaining glass plate provided in front of the CCD camera. By placing them in close contact,
Even if a part of the light emitted from the illumination light source is reflected by the glass plate, it is reflected again by the glass plate having a low refractive index inside the glass plate, so that it does not enter the CCD camera. According to the head of the pipe camera of the present invention,
An airtight glass plate provided in front of the CCD camera is integrated, and it is not particularly difficult to airtightly hold this glass plate at the tip of the housing. Further, since the glass plate having a low refractive index is simply placed inside the glass plate so as to be in close contact with the glass plate, the number of parts is increased and the cost is not increased particularly. Furthermore, since the glass plate is closely attached to the inside of the outer glass plate for maintaining the airtightness, the strength of the glass plate is increased as compared with the case of the outer glass plate alone, and the head portion of the pipe camera itself becomes stronger.

[Brief description of drawings]

FIG. 1 is a sectional view showing an example of an embodiment of a head of a pipe camera of the present invention.

FIG. 2 is an explanatory diagram showing a state of light emission from the head of the pipe camera of FIG.

FIG. 3 is a cross-sectional view showing an example of the head of a conventional pipe camera.

FIG. 4 is a cross-sectional view showing another example of the head of the conventional pipe camera.

[Explanation of symbols]

 1 Pipe camera housing 2 Observation equipment 3 Airtight outer glass plate 4 Inner glass plate to prevent light from wrapping around 10 Light guide 11 CCD camera

Claims (1)

[Claims] 1. A CCD camera is arranged in the center of the housing, and an illumination light source is arranged around the CCD camera.
At the head of the pipe camera in which a glass plate for maintaining airtightness is held at the tip of the housing in front of the CCD camera, a light source for illumination around the CCD camera is arranged close to the glass plate for maintaining airtightness. In the pipe camera, a glass plate having a refractive index lower than that of the glass plate for maintaining airtightness is arranged in close contact with the glass plate for maintaining airtightness on the inner peripheral side of the light source for illumination. head.