FR2562359A1 - Optical switch with light source and signal generator - Google Patents

Abstract

The signals, generated by a photosensitive device, characterised the light magnitude impinging on the device. Between the light source and this device is provided a photosensitive path. Numerous switching members comprise an actuating part and a shutter element each, both interconnected for a commom movement over a corresponding path across the light path. Each shutter element is marked with a unique surface pattern blocking selectively the light transmission along the photosensitive path when the shutter element moves across the photosensitive path. The state of the switching members is detected by insertion of the identifying sgnal. Pref. the light path is formed by an optical glass fibre with an intermediate space, through the shutter elements can be selectively moved.

Description

"Optical switching device, and apparatus for implementing it
The invention relates to the field of switches, and more generally of switching devices.

It presents a switching device using optical elements.

 The prior art includes a large number of switching devices, controlled by an operator, and intended to selectively control a plurality of loads, as can be found in domestic installations or in automobiles. For example, in the case of a direct switching control device, a switch is provided for direct control of each of the loads.

In this type of device, the total load current flows through each of the switches, which requires the use of high-power switches and wiring. In addition, this type of device has safety risks to the extent that in the event of a switch failure, the operator is likely to receive an electric shock. Another type of switching device is the electrical switching matrix, which uses low-voltage signals, time-sharing, over a series of lines, to code the switching inputs. Low voltage operation makes the matrix sensitive to electromagnetic noise, and the multi-line coding diagram requires a large number of controls and inputs, and extensive wiring.

 Consequently, an object of the present invention is to provide an improved switching device which is not subject to the shortcomings and disadvantages of the devices of the prior art, and more particularly which is not sensitive to noise. electromagnetic and does not present a risk of electric shock to the operator.

 With the advent of micro-computer control of installations, great flexibility can be obtained. However, the use of microcomputers imposes certain constraints. For example, the number of inputs to a microcomputer is limited. Likewise, the signals introduced into a microcomputer must be digital by nature. It is therefore another object of the present invention to provide a switching device which is compatible for use with a microcomputer, and which requires only one input to the microcomputer, this input being in digital form.

 In addition, in an automobile having a large number of electrically controlled devices, such as locking the doors, operating the windows, opening the trunk, etc., the driver's door or the dashboard may include a large number switches. It would be desirable to reduce or limit the number of wiring wires connected to the door or dashboard. Automobiles are therefore using more and more microcomputers, which corresponds to the same objectives listed above.

 According to the invention, the objects mentioned above, as well as other objects, are achieved by means of an optical switching device characterized in that it comprises a light source; photosensitive means providing a signal representative of the amount of light they receive; means for routing the light beam between said light source and said photosensitive means; a plurality of interrupting elements, each comprising an operating mechanism, as well as a screen element connected to said operating mechanism and driven by said movement of the mechanism along a path transversely intercepting the light beam, each of said screen elements being marked by an original configuration of zones selectively interrupting the transmission of light of said light beam when said screen elements interceptht said light beam; and means for using said signal to determine the state of each of said interrupt elements.

 According to an advantageous characteristic of the invention, the light conveying means comprise a fiber optic light guide, having at least one pure beam, through which the screen elements can selectively be moved.

 According to another characteristic of the invention, each of the screen elements comprises a transparent substrate, carrying a coded configuration of parallel opaque bands, the bands extending transversely to the direction of movement of the screen element towards the beam. luminous.

 The invention also relates to an apparatus for implementing the device considered, characterized in that it comprises a shoemaker; a first conduit passing through said shoemaker; a plurality of interrupting elements, each comprising an operating mechanism, and a screen element, connected to said operating mechanism, and driven in movement with said mechanism along a path transversely intercepting said first channel, each of said screen elements being identified by an original configuration of zones selectively interrupting the transmission of light along said first conduit when said screen intercepts said conduit; a plurality of secondary conduits made in said case, each of said secondary conduits crossing said first conduit, and being dimensioned to receive and guide a screen element through the intersection of said secondary conduit with said first conduit; means for connecting a light source to a first end of said first conduit; and finally, means for connecting a light detector to a second end of said first conduit.

Other characteristics and advantages of the invention will appear on reading the following description of a preferred embodiment of the invention, as well as the appended drawings, in which the same reference numerals designate the same elements: q; 1 represents a schematic block diagram of a system comprising a switching device according to 1 1invention;
- Fig. 2 shows a plan view of an embodiment of a switching device constructed according to the principles of the invention;
- Fig. 3 shows a view, in partial section, substantially corresponding to section 3-3 of Figure 2;
- Fig. 4 is a detailed view of part of the device shown in Figures 2 and 3, along line 4-4 of Figure 3;
- Fig. 5 is an enlarged view showing a detail of a screen element of the device shown in FIGS. 2, 3 and 4.

 Referring to the drawings, Figure 1 schematically shows, by way of illustration, a system for describing the principles of the present invention. This system comprises a control unit 10 with microcomputer, for controlling a plurality of loads 12 as a function of a program stored in the microcomputer 14, this through a plurality of relays 16. This system can other, for example, a washing machine dishes, in which the loads 12 correspond to the various operational components of the machine, such as the filling valve, the detergent supply device, the drain pump, etc., these elements being controlled according to a program stored at inside the microcomputer 14, and according to the operating cycle selected by the operator.

According to another application, the system can be intended to control individual loads in an automobile. The control of the system represented in FIG. 1, by an operator, is carried out by means of a switching device 18, coupled to the microcomputer 14. In its simplest form, the switching device 18 comprises a light source 20, a light detector 22, and means for routing a light beam between the light source 20 and the light detector 22,
Preferably, these means of routing the light beam comprise a light guide 24 of optical fiber. The light guide 24 is discontinuous in a certain number of places, in order to present a plurality of cuts. Each of these cuts corresponds to an interrupting element controllable by the operator. Each of the interrupting elements comprises an operating mechanism 26, and a screen element 28, coupled to the operating mechanism 26, so as to be driven in movement. The interrupting elements are arranged in such a way that when the operator moves one of the operating mechanisms 26, the screen element 28 which corresponds to it moves along a path crossing the corresponding cut in the fiber light guide 24 optical. Each of the screen elements 28 is marked by an original configuration of zones, which selectively intercept the light emitted by the source 20, when the screen 28 moves in the cut.

 The light detector 22 then produces a signal constituting the input to the microcomputer 14, said signal being digital by nature, and providing a unique signature corresponding to one of the elements 28 forming a screen which has been moved. The microcomputer 14 uses this signal to determine the state of the interrupting elements.

 It can be noted, from the device represented in FIG. 1, that the interrupting elements are arranged in such a way that the light guide 24 with optical fiber connects them all in series. With this device, it is only necessary to have a single light source 20 to supply the light, and a single light detector 22 will suffice to read all the interrupt codes. The code read by the light detector 22, and supplied to the microcomputer 14 contains three pieces of information for the use of the microcomputer 14. The first piece of information is a unique code of the controlled interrupt element, which allows to identify it from others. The code also contains information regarding the direction in which the screen is moving. The microcomputer 14 can use this information to assess, if necessary, how long the interruption is maintained. The final piece of information is the speed at which the screen crosses the cutoff. The microcomputer 14 uses this speed information to read the code. Only one of the interrupting elements can be actuated at any given time, the microcomputer 14 being configured to detect and ignore multiple inputs.

 Figures 2 to 5 show an apparatus for implementing, by way of illustration, the switching device 18 of Figure 1. The switching device illustrated in Figures 2 to 5 comprises nine interrupting elements, although 'It is clear that any lower or higher number of elements can be considered. The switching device comprises a case, which is composed of four blocks 30, 32, 34 and 36. The blocks 30 to 36 are fixed to each other by means of nuts 40 cooperating with threaded rods 38 passing through bores aligned made through the blocks 30 to 36, and counter-bored in the blocks 30 and 36. The blocks 30 to 36 have open grooves, or else conduits 42, which are closed by means of the plate 44 of the shoemaker. The blocks 30, 32 and 34 also include countersunk conduits 46, which are closed by the adjoining walls of the blocks 32, 34 and 36. These conduits 46 cross the conduits 42 and are dimensioned to receive the screen elements, as described in detail below.

The shoemaker's plate 44 is provided with orifices 48 which are the extension of the conduits 46. The plate 44 is fixed to the block 30 and 36 by means of the threaded ends of the exagonal spacers 50 of support, to which is fixed in its turn a plate of base 52.

Each of the interrupting elements comprises a control rod, having a flat head portion 54, mounted on a shoulder rod, threaded at the end opposite to the head portion 54. The rod 56 is mounted in an orifice 58 drilled in the shoemaker, the orifice 58 being dimensioned to receive the widest part of the rod 56. The narrowest part of the rod 56 passes through an opening 60 of suitable size, made in the spike 44 of the shoemaker. A compression spring 62 surrounds the smallest portion of the rod 56, and is in contact between the plate 44 of the shoemaker and the shoulder of the pin 56, in order to elastically push the head portion 54 relative to the shoemaker . An action block 64 is mounted on the rod 56. This is achieved by practicing a partially tapped hole passing through the block 64 to which the rod 56 is fixed, a nut 66 being screwed to the end of the rod 56 projecting from the block 64. A centering pin 68 forcibly mounted in a corresponding orifice in the block 64 is housed in a slightly oversized orifice 70 made in the case, after having passed through a hole in the plate 44. The centering pin ensures the guiding the actuating block 64 and prevents it from rotating when it moves with the rod 56. A screen element 72 is mounted on each of the actuating blocks 64. The screen element 72 is formed in the form of a '' a generally rectangular transparent substrate, for example mylar with a unique configuration of opaque bars, some being narrow and some wide. These bars provide a code corresponding to each individual interrupt element. Each of the actuating blocks 64 comprises a duct 74 in which the screen element 72 is mounted, for example by means of a screw 76 and a nut 78 passing through aligned bores made in the actuating block 64 and the screen element 72. For the routing of light between a light source and a light detector, a fiber optic light guide is used. This fiber optic light guide is mounted inside the duct 42 and forms loops, as shown in FIG. 2, in order to constitute a single light path crossing in series all the elements 72 forming a screen. The light guide 80 with optical fiber is interrupted to form cuts, for example of a wide z of 0.38 millimeter, at the level of the conduits 46 daa lesqrffl the elements 72 are shielded,
When the operator wishes to actuate a particular interrupting element, the head 54 of the positioning rod 56 is pressed in the direction of the case. This causes the downward movement of the block 64 carrying the element 72 forming a screen , as shown in Figure 3. As can be seen on the interrupting element located furthest to the right in Figure 3, in the rest position the e light guide 80 with optical fiber is located next to a portion "clear" of the element 72 forming a screen, which allows the light to continue its path along the light guide 80. When the element 72 forming a screen is moved downward, the configuration of opaque bars crosses the corresponding cut of the light guide 80, which causes the production of a single configured signal generated at the light detector output, and corresponding to this particular interrupting element. When the actuating rod 56 is moved towards bottom, spring 62 is compressed, and lo When the operator releases the pressure, the interrupting element returns to its rest position. As illustrated by the interrupting element located in the middle of FIG. 3, the complete movement of the actuating rod 56 causes only the entire configuration of the elements 72 forming the screen to pass past the light guide 80.

 Consequently, the described optical switching device has a large number of advantages. This device is not sensitive to electromagnetic noise, since the transmission channel transmits light energy. s A single fiber optic loop is used to transmit and receive signals from multiple switches. As a result, only one computer input is needed to "read" multiple switches. The light signal is digital by nature, and is therefore not sensitive to minor modifications to components, while being directly compatible with the computer. When reprogramming the computer, the operation of one of the switches switches can be changed, for example to provide alternating action instead of momentary action, or its function in the system can be changed. As the electricity does not intervene in the interrupting elements, there is no danger of electric shock.

 it is clear that the preceding description relates to a preferred embodiment of the invention, given by way of illustration, but that the present application aims to protect all the possible variants without departing from the spirit of the invention. By way of example, another embodiment may include switches which are not push-button switches but, for example, limit switches, quick switches, or even position encoders Similarly, the fibers optics may further be multiplied and then combined so that a single source and a single detector can be connected by multiple fiber paths Finally, although the example taken concerns the transmission of light, the design of the system can be modified so that the light emanating from the source fiber is reflected or not in the detector fiber, rather than transmitted or blocked as in the case described.

Claims (4)

CLAIMS 10) Optical switching device characterized in that it comprises a light source (20); photosensitive means (22) providing a signal representative of the amount of light they receive; means (24) for routing the light beam between said light source t20) and said photosensitive means (22); a plurality of interrupting elements, each comprising an operating mechanism (26), as well as a screen element (28) connected to said operating mechanism (26) and driven by said movement of the mechanism (26) along a path transversely intercepting the light beam, each of said screen elements (28) being marked only by an original configuration of zones selectively interrupting the transmission of light of said light beam when said screen elements (28) intercept said light beam; and means (14) for using said signal to determine the state of each of said interrupt elements. 20) Device according to claim 1, characterized in that said means for routing the light beam comprise a light guide (24) with optical fiber having at least one cut, through which said elements (28) forming a screen are selectively movable . 30) Device according to claim 1, characterized in that each of said screen elements (28) comprises a transparent substrate having a coded configuration of parallel opaque bands, said bands extending transversely to the direction of movement of the parts (28) forming screen towards said beam.  40) Apparatus for implementing the optical switching device according to any one of claims 1 to 3, characterized in that it comprises  - a bootmaker (30,32,34,36);  - a first conduit (42) passing through said shoemaker;  - A plurality of interrupting elements, each comprising an operating mechanism (64), and a screen element (72), connected andit operating mechanism (64), and driven in movement with said mechanism along a transversely intercepting path said first channel (42), each of said screen elements (72) being marked by an original configuration of zones selectively interrupting the transmission of light along said first conduit (42) when said screen (72) intercepts said conduit (42); ;  - a plurality of secondary conduits (46) produced in said housing, each of said secondary conduits (46) crossing said first conduit (42), and being dimensioned to receive and guide a screen element (72) through the intersection of said conduit secondary with said first conduit;  - means for connecting a light source to a first end of said first conduit (42); and means for connecting a light detector to a second end of said first conduit (42).  5) Apparatus according to claim 4, characterized in that it comprises an optical fiber (80) inside said p @ emier conduit (42), said fiber (80) having a plurality of @ braces, each disposed at l 'intersection of one of said secondary co @@ u @ ts (46) with said first conduit (42).  6) Apparatus according to claim 4, characterized in that each of said elements (72) forming a screen comprises a transparent aubstuat carrying a coded configuration of parallel opaque bands, said bands extending transversely to the said displacement of the element. (72) forming a screen at the corresponding secondary interior.  7) Apparatus according to claim 6, characterized in that each of said operating mechanisms (64) comprises @@ @@ oc movens for mounting said element (72) forming @@@ an @@@ said block, a member of maneuver accessible to the o @@@@@@@ conu @ ecté audit blce. and movable with respect to said @@@@@@ such that the screen element (72) is  @@@@@@@ @@@@ @ @ @ @ elongation of the secondary duct (46) which co @ @@@@@@@ @@ @ when said @ @@ is moved by an operator, er means of elastic reop @ of said organ in a given direction