JPS623889Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an imaging device, particularly to an arrangement structure of a bias light source.

In general, photoconductive image pickup tubes used in imaging devices have a so-called afterimage, in which there is a slight delay in the electrical signal following changes in the optical signal.
This often degrades the TV picture quality. It is known that, in an image pickup tube using a blocking photoconductive film such as Sachicon, this afterimage can be reduced by using a bias light that always provides a constant optical signal in a biased manner.

On the other hand, as a means of supplying bias light to the face plate of an image pickup tube, a bias light light source is provided outside the tube, a hole for bias light irradiation is provided in the electrode inside the tube, and the bias light is introduced into the tube through this hole. A method is adopted in which a bias light is irradiated onto a photoconductive target while causing diffuse reflection from the inner wall.

However, in the imaging device having such a configuration, it is extremely difficult to attach the bias light source to the outer surface of the tube closest to the irradiation hole due to structural constraints, and the light utilization rate is extremely poor.

In order to solve this problem, it has been proposed to provide convex lenses in front of bias light sources that are equally distributed, but such a configuration complicates the assembly and structure. At the same time, sufficient bias light could not be obtained.

Therefore, an object of the present invention is to provide an imaging device that can eliminate the above-mentioned conventional drawbacks and improve light utilization efficiency with a simple structure.

In order to achieve this purpose, the imaging device according to the present invention is provided with a ring-shaped condensing convex lens that covers the bias light source, and the bias light source is held and fixed, and the light is focused on the bias light irradiation hole. be. The imaging device according to the present invention will be described in detail below with reference to the drawings.

Figures 1 to 3 show an example of the imaging device according to the present invention, with Figure 1 being a sectional view of the main part, and Figure 2 being
The figure is a perspective view of the main part, and FIG. 3 is a sectional view taken along the line -' of FIG. 1. In these figures, the transparent envelope 1
A face plate 3 with a photoconductive target 2 formed on its inner surface is placed at the interface end of the indium metal 4.
A ring-shaped signal electrode 5 is provided on the outer peripheral surface of the indium metal 4 . Also, inside the envelope 1, a face plate 3 is provided.
A mesh electrode 6, a cylindrical accelerating electrode 7, etc. are arranged coaxially in order from the photoconductive target 2 side.
Bias light irradiation holes 8a, 8b, 8c, and 8d are provided on the circumferential surface of the accelerating electrode 7 so as to be equally distributed. Further, a ring-shaped convex convex lens 9 is disposed on the outer peripheral surface of the envelope 1 close to the irradiation holes 8a to 8d. Bias light sources 11a, 11b, 11c, and 11d are held and fixed to have an integrated structure so that bias light light 10 can be incident on each of them. In this case, the bias light sources 11a to 11d are fixed by providing mounting holes for the bias light sources 11a to 11d on the back surface of the convex lens 9 when forming the ring-shaped convex lens 9 by plastic molding. Insert 11a to 11d,
For example, it is fixed with adhesive or the like.

According to such a configuration, the light emitted from the bias light sources 11a, 11b, 11c, and 11d is efficiently focused by the ring-shaped convex condensing lens 9 to the irradiation holes 8a, 8b, 8c, 8d, the light utilization efficiency of the light sources 11a to 11d can be significantly improved. Also,
The condensing convex lens 9 is configured in a ring shape to form an envelope 1.
By arranging the bias light sources 11a to 11d on the outer peripheral surface of the convex lens 9, the bias light sources 11a to 11d can be held and fixed on the back side of the convex lens 9, thereby greatly simplifying the arrangement structure and assembly structure of the bias light sources 11a to 11d. be able to.

In the above embodiments, the bias light source may be a light bulb or a light emitting diode. Further, although the case where four bias light sources 11a to 11d are provided has been described, the present invention is not limited to this. Furthermore, the convex lens is not limited to a plastic lens.

As explained above, according to the present invention, it is possible to improve the light utilization efficiency with a simple configuration, so that an extremely excellent effect can be obtained that can significantly improve the reliability and productivity of the image pickup tube.

[Brief explanation of drawings]

1, 2, and 3 are a sectional view of a main part, a perspective view of a main part, and a sectional view taken along the line -' of FIG. 1, showing an example of an imaging device according to the present invention. 1... Envelope, 2... Photoconductive target, 3...
...Face plate, 4...Indium metal, 5
...Signal electrode, 6...Mesh electrode, 7...Acceleration electrode, 8a, 8b, 8c, 8d...Bias light irradiation hole, 9...Convex lens, 10...Light, 11
a, 11b, 11c, 11d...bias light source.

Claims (1)

[Scope of utility model registration request] A light-transmitting envelope, a photoconductive target formed on the inner surface of one end of the envelope, and an electron gun having at least one cylindrical electrode and forming an electron beam to scan the target. and a bias light light source for applying bias light to the photoconductive target, the imaging device includes a plurality of irradiation holes provided on the side surface of the cylindrical electrode, and a plurality of irradiation holes provided in the vicinity of the irradiation holes. a convex lens disposed on the outer periphery of the envelope, having a mounting hole for the bias light source at a position corresponding to the irradiation hole, and covering the bias light source mounted in the mounting hole; a ring-shaped condensing convex lens having a cross-sectional shape and surrounding the outer periphery;
and the bias light light source mounted in the mounting hole, and the light from the bias light light source is focused by the condensing convex lens, enters the irradiation hole, and is then reflected on the inner surface of the cylindrical electrode. An imaging device configured to illuminate the photoconductive target.