JPS6224897B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an imaging device, and particularly to an imaging device in which bias light is supplied from the inner surface of a face plate.

In general, photoconductive image pickup tubes have a phenomenon called afterimage, in which there is a slight delay in electrical signals following changes in optical signals, which often deteriorates television image quality. It is known that, for example, in an image pickup tube using a blocking photoconductive film such as Saticon, this afterimage can be reduced by a bias light that always provides a constant optical signal in a biased manner.

On the other hand, as a method for supplying bias light to the face plate of an image pickup tube, a light source is provided inside an optical system consisting of an imaging lens or a color separation system, and the bias light is irradiated and superimposed on a photoconductive target from the face plate side. It has been adopted.

However, according to this method, since the light source is provided inside the optical system, it is difficult to uniformly irradiate the bias light onto the photoconductive target due to structural limitations of the optical system, and in a multi-tube camera, each It was difficult to uniformly illuminate the image pickup tube with the required amount of bias light.

Furthermore, according to the method of arranging the light source immediately before the face plate of the image pickup tube, that is, after the optical system, it is extremely difficult to design the light source if there is no space available. In addition, in this case, the light from the light source is not parallel to the tube axis, but enters the face plate from an oblique direction, and there is an optical discontinuity between the photoconductive target and the light source, for example. If the anti-flare glass chip is placed, it will cause uneven light intensity on the photoconductive target, impairing the uniformity of the imaged image.

Therefore, in an attempt to solve these drawbacks, a bias light source is placed on the stem side of the image pickup tube, a light pipe or a light diffusing plate is provided inside the tube, and the bias light is irradiated onto the photoconductive target. A method is proposed.

However, according to the above method, the light pipe or the light diffusing plate is usually made of glass or Teflon, which is not preferable in terms of handling or degassing for vacuum use.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide an imaging apparatus which eliminates the above-mentioned drawbacks and which uniformly and efficiently irradiates a photoconductive target with bias light.

In order to achieve this purpose, the imaging device according to the present invention includes a light source provided close to the envelope, and the light from the light source is introduced into the envelope to irradiate the photoconductive target with bias light. This is what I did. DESCRIPTION OF THE PREFERRED EMBODIMENTS An imaging device according to the present invention will be described in detail below with reference to the drawings.

The figure is a sectional view of essential parts showing an example of an imaging device according to the present invention. In the figure, 1 is an envelope made of a transparent material such as glass, and this envelope 1
A face plate 4 having a photoconductive target 3 formed by vapor deposition on its inner surface is sealed to the open end of the face plate 4 through a seal portion 2 made of, for example, indium, and is held inside the face plate 4 or in a vacuum. In addition, this envelope 1
Inside, facing the photoconductive target 3, a mesh electrode 5, a cylindrical acceleration electrode 6, a second grid electrode 7, a first grid electrode 8, and a cathode 9 are arranged on the same axis at a predetermined distance apart. It is stored. Furthermore, light sources 11a and 11b for bias light connected to a power source 10 are arranged close to the outer peripheral surface of the envelope 1. In this case, the light sources 11a, 1
1b can be housed in a recess provided in a structure such as a deflection coil or a focusing coil (not shown) wound around the outer periphery of the envelope 1. The envelope 1 facing the light sources 11a and 11b
The light sources 11a, 1 are provided on the side surface of the acceleration electrode 6 inside.
Light passing holes 6a for introducing the light 1b are provided axially symmetrically at a plurality of locations. Further, at one end of the accelerating electrode 6, a funnel-shaped light reflecting plate 6b whose inclined surface faces the light passing hole 6a is fixedly arranged.

In such a configuration, the light sources 11a and 11b
When the light sources 11a and 11b are turned on, the light emitted from the light sources 11a and 11b is introduced into the accelerating electrode 6 through the flesh of the envelope 1 and the light passing hole 6a, and is reflected by the light reflecting plate 6b and the inner wall surface of the accelerating electrode 6. Furthermore, the light from the light sources 11a and 11b that enters the flesh of the envelope 1 is reflected and diffused within the flesh, and is irradiated in the direction of the photoconductive target 3 to produce bias light beam 12.
As a result, three surfaces of the photoconductive target are uniformly irradiated. In this case, in order to make the bias light as uniform as possible on the surface of the photoconductive target 3, it is possible to easily achieve this by roughening the reflection surface of the light reflection plate 6b and making the incident light diffused. can. Further, in order to increase the number of reflections on the inner wall surface of the accelerating electrode 6 as much as possible to make the light uniform, this can be easily done by adjusting the inclination angle of the light reflecting plate 6b. According to this method, since the light reflecting plate 6b can be made of metal, handling problems and degassing are extremely easy. In addition, the bias light light sources 11a, 11
Since b can be provided inside a structure such as a deflection coil or a focusing coil (not shown), there is no spatial restriction at all.

As explained above, according to the imaging device according to the present invention, it is possible to uniformly irradiate a photoconductive target with bias light extremely easily and efficiently, and extremely excellent effects such as ease of handling can be obtained. It will be done.

[Brief explanation of the drawing]

The figure is a sectional view of essential parts showing an example of an imaging device according to the present invention. DESCRIPTION OF SYMBOLS 1... Envelope, 2... Seal part, 3... Photoconductive target, 4... Face plate, 5... Mesh electrode, 6... Accelerating electrode, 6a... Light passing hole, 6b... Light reflection Board, 7...Second grid, 8...
1st grid, 9... cathode, 10... power supply, 11a,
11b...Light source, 12...Bias light light.

Claims (1)

[Claims] 1. An electron gun that has a transparent envelope, a photoconductive target formed on the inner surface of one end of the envelope, and at least one cylindrical electrode, and forms an electron beam that scans the target. In an imaging device equipped with an image pickup tube, a plurality of light sources for bias light are arranged along the outer periphery of the envelope, a light passage hole is provided in the side surface of the cylindrical electrode, and the surface is rough. A funnel-shaped light reflecting plate is disposed within the cylindrical electrode so that its side surface is inclined at an acute angle with respect to the axis of the cylindrical electrode, and the light entering the cylindrical electrode through the light passage hole is disposed within the cylindrical electrode. An imaging device characterized in that the light from the light source is diffusely reflected by the light reflecting plate and then further reflected by the inner wall surface of the cylindrical electrode to illuminate the target.