FR2596548A1 - Designation device for a digital calculator - Google Patents

Abstract

The invention relates to a designation device composed of sheets with conducting layers. These layers are divided into tracks distributed according to a binary numbering system 1. An associated switching device 2 allows indexing of the designation area by establishing a DC electrical link between the tracks of the designation area. The use of transparent sheets allows a touch screen to be produced.

Description

The present invention relates to a device intended to be used as a designation means for a digital computer.

 It belongs to the category of designation systems composed of sheets with a conductive layer.

Such a device consists of 2 or more flexible insulating sheets, transparent or not, one of the faces, possibly both, is made conductive by depositing a product having a reduced resistance to electric current, this product can be metallic nature.

The designation is obtained by exerting pressure at a point in the designable space, a contact then being established between two adjacent layers. This pressure can be carried out simply by touching with the finger, or by the intermediary of any suitable instrument.

The location of the designated area can be done either by dividing the conductive layers into rows and columns, or by performing a resistance measurement between the designated point and one of the edges of the sheet.

The drawbacks of these two methods are, in the first case, the need for a number of connections equal to the sum of the rows and columns, with a corresponding electronic interface, and in the second, the complexity of the electronic interface as well as the lack of reliability over time specific to analog systems in general.

The method according to the invention tends to reconcile the simplicity and reliability of the first of the above methods, with the great theoretical definition of the second.

The device comprises three or four sheets with a conductive layer, as well as a switching system. (2)

The following description relates only to two adjacent conductive layers, which are intended to come into contact at the time of designation.

One of these layers (denoted 1 in FIG. 1) is divided into a certain number of zones, these zones being materialized by conductive tracks called "tracks l" and "tracks 0". These tracks are distributed in accordance with the binary code of the zone concerned.

Each track is linked, according to its weight in the binary numbering system used, to the corresponding switching element.

The other layer (layer 3 is divided into conductive tracks which aim to establish connections between some of the tracks of layer 1. These tracks are shown hatched in Figure 1
These tracks are distributed so as to establish, at the time of designation, a continuous electrical connection between the switching elements and the tracks of layer 1
The digital computer connected to the system will be able to interrogate the designation device, this by successively displaying on the switching system all the codes corresponding to the different zones. When there is a correspondence between the displayed code and that of the designated area, a positive response is obtained to the continuity check of the electrical connection, thus allowing the location of the designated area.

The zones of layer 3 may be distributed in the form of rectilinear bands going from one edge to the other of the designatable space. The designation will relate to one or more of these bands. Another set of 2 sheets can then be placed on the first, the strips of the second set being oriented 90 of those of the first.

This will result in a row and column designation system with binary coding.

The two central sheets of this set may be replaced by a single one which will then have a conductive layer on each of these faces, these two conductive layers being similar to those of each of the two sheets removed.

When the number of zones in layer A will be such that the corresponding binary code will be composed of an odd number of bits, the return of the electrical connection will be made by a track (4) reserved for this purpose on layer 3 (See figure 2)
The switching system associated with the device is composed of a certain number of electrical or electronic switching elements, interconnected according to FIG. 2. The number of elements is equal to the number of bits of the binary code corresponding to the number of zones used.

The device according to the invention is particularly intended for use with a digital computer, the different areas of the designatable space being coded according to a binary number system.

If transparent sheets are used, the designation system can be placed on the screen of a display device. This produces a set known as the "touch screen".

Claims (3)

 1) Designation device composed of insulating sheets comprising conductive tracks distributed according to a binary numbering system, characterized in that the detection of the code of the designated area is carried out by the establishment of a continuous electrical connection between the tracks of the designated area via an associated switching device. 2) Device according to claim (1) characterized in that the establishment of the electrical connection takes place via the conductive tracks distributed on a second insulating sheet. 3) Device according to claim (2) characterized in that the return of the electrical connection is effected by a track provided for this purpose on the second sheet when the number of bits of the code used is odd.