JPH01143257A - Electrostatic shielding film - Google Patents

Abstract

PURPOSE:To reduce the influence of electrical noise by superimposing a conductive film and an insulating film on an insulating substrate and providing the conductive film with a specific potential. CONSTITUTION:An insulating substrate 11 includes an electrically conductive film 12 and an insulating thin film 13 superimposed thereon in order, the insulating thin film 13 having a thin film element 14 formed thereon. The electrically conducive film 12 is made at an earth potential or a specific potential, so that it serves as a shielding member for the thin film element 14, the member being located in close vicinity of the element. The effect of the shielding is further improved by superimposed an insulating layer 15 and an electrically conductive thin film 16 on the thin film element 14 and to sandwich the thin film element 14 between the electrically conductive thin films 12, 16.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to an electrostatic shielding film that reduces electrical noise in elements that handle weak electrical signals, such as contact image sensors and TPTs, and the structure of electronic devices using the film.

[Conventional technology] The prior art will be explained using an example.

Figure 1 shows a TPT using amorphous silicon, with an insulating substrate (1), a gate electrode (2), an insulating film (3), an amorphous silicon 71 layer (4), and an amorphous silicon n'
Ji (5) and an electrically conductive film (6) are laminated.

These TPT elements are arranged on a plane and used, for example, to drive a liquid crystal.

Since amorphous silicon TPT has a very high ON resistance, it is very susceptible to electrical noise when used in a microcurrent switching element.

Figure 2 shows an image sensor using amorphous silicon, which is a Schottky diode type image sensor consisting of an electrically conductive film (8), an amorphous silicon 71 layer (9), and a transparent electrically conductive film (00) on an insulating substrate (7). It is.

Usually, this type of image sensor has a dark current of only a few picoamperes (PA) L, so it is very susceptible to electrical noise.

Additionally, in the case of thin film devices, which end of the device is generally more susceptible to the effects of electrical noise.

[Structure of the Invention] The present invention is a structure in which the influence of electrical noise can be reduced by placing a conventional ground shield near a thin film element.

FIG. 3 shows the configuration of the present invention.

Figure (A) shows an electrically conductive film 02) on an insulating substrate 01),
Insulating thin film surfaces are sequentially laminated and a thin film element 04 is placed on top of the insulating thin film surface.
) to form. By setting the electrically conductive film Q2) to a ground potential or a specific potential, it can be used as a shield close to the thin film element 04).

In addition, in the same figure (B), an insulating layer 05) and an electrically conductive thin film 06) are laminated on the thin film element side, and a thin film element 04) is laminated on the electrically conductive thin film 0.
2) and 06) can be sandwiched together to further increase the shielding effect.

〔Example〕

FIG. 4 shows an embodiment of the present invention.

This example is an example in which the electrostatic shielding film of the present invention is applied to an image sensor.

A 1μ film of 5nOz08) was formed as an electrically conductive film on a glass substrate 07) by a known sputtering method, then a 1 μs film of 5iOz09) was formed by a known thermal CVD method, and a-3t film was formed on top of that by a known plasma CVD method. (to) n layer ■ layer n layer each 0.1.1. Olo, 1 μs film formation, epoxy resin (23) as an insulating layer was formed on it by a known screen printing method, and then Affi (23) was formed as an electrically conductive film.
4) was formed by a known sputtering method, thus completing a shield structure type Mi3i image sensor.

In order to demonstrate how excellent the electrical noise resistance of the image sensor of this example is, a comparison was made with an image sensor that does not use the electrostatic shielding film of the present invention.

Figure 5 (A) shows the reading signal when these two samples read the same original (pure black original).
) (B).

Figure (A) shows the read signal of the image sensor when the shielding film of the present invention is not used, and shows the signal output for each bit of the 8/4 image sensor, and it shows the switching noise for driving. , it can be clearly seen that each signal varies due to static electricity, etc.

In the case of the image sensor using the shielding film of Rikiki's invention, the signals for each bit are almost constant, and no variations are observed, as shown in FIG.

As described above, by using the shielding film of the present invention, it is possible to improve the shielding effect for thin film functional elements that handle extremely weak signals of several nanoamperes (nA) to several picoamperes (pA), and easily eliminate electrical noise. It has become possible to commercialize thin film applied products that are resistant to

[Effect] A shielding effect can be achieved for thin film elements that handle weak signals of several A to several pA, and it has become possible to easily put into practical use thin film applied products that are resistant to electrical noise.

Conventionally, noise had to be corrected using a correction circuit, etc.
For this reason, a complicated correction circuit was required, but the shielding film of the present invention has made it possible to realize it with only a simple correction circuit.

[Brief explanation of the drawing]

FIGS. 1 and 2 show the structure of a conventional element susceptible to electrical noise. 3 and 4 show the structure of an element to which the electrostatic shielding film of the present invention is applied. Part 5 shows the state of the read signal from the image sensor. P, very dangerous. Figure 5

Claims (1)

[Claims] 1. An electrostatic shielding film in which a conductive film and an insulating film are laminated on an insulating substrate, and the conductive film is set to a certain potential. 2. An electrostatic shielding film according to claim 1, in which an element for flowing a weak current is formed on an insulating film, and then an insulating layer and a conductive film are laminated, and the upper and lower conductive films are set to a specific potential.