FR2558628A1 - SWITCHING DEVICE / DISPLAY - Google Patents

Abstract

THE INVENTION RELATES TO A DISPLAY SWITCHING DEVICE THAT CAN DISPLAY DIFFERENT INDICATIONS. IT INCLUDES A TRANSPARENT DIELECTRIC PANEL 10 CARRYING, ON ITS REAR FACE, A FIRST SET OF PARALLEL AND EXTENDED ELECTRODES 11 IN TRANSPARENT CONDUCTIVE MATERIAL, A LAYER 13 OF LUMINESCENT SUBSTANCE IN CONTACT WITH THE ELECTRODES 11 AND A SECOND SET OF ELONGATED ELECTRODES 14 IN CONTACT WITH THE BACK SURFACE OF LAYER 13, THE ELECTRODES 14 BEING INCLINED WITH RESPECT TO THE ELECTRODES 11 SO AS TO FORM A MATRIX OF CROSSING POINTS. A CONDUCTIVE TRANSPARENT LAYER 12 IS APPLIED TO THE FRONT SIDE OF THE PANEL 10, ABOVE THE FIRST SET OF ELECTRODES 11. FIELD OF APPLICATION: COMBINED SWITCHING AND DISPLAY DEVICES INTENDED IN PARTICULAR FOR USE WITH MICROPROCESSOR SYSTEMS, ETC.

Description

The invention relates to switching / display devices. The patent

  British Patent No. 2,002,522 discloses a touch switch which incorporates an electroluminescent display element. The switch may be arranged to be illuminated, or so that an inscription it carries is illuminated,

  when actuating said switch. The illuminated area

  The switch is defined by an insulating mask which determines the excitation range of a phosphor layer. The area that can be illuminated must therefore be fixed to the manufacture of the switch and the latter is therefore suitable for the control only of a

  function. The invention relates to a switching device

  display in which the display can be modified

  electronically, which makes it possible to obtain a

  programmable multi-function controller.

  According to one aspect of the invention, a switching / display device comprises: a transparent dielectric panel; a first set of elongate parallel electrodes formed of a transparent conductive material on the back surface of the

  dielectric panel; a layer of phosphor

  in contact with the first set of electrodes; a second set of elongated parallel electrodes mounted in contact with the rear surface of the phosphor layer, the second set of electrodes being inclined with respect to the first set of electrodes so that the electrodes of the first set overlap those of the first set of electrodes; another game to form a matrix of points; and a transparent conductive layer formed on the front of the dielectric panel and extending

  above the first set of electrodes.

  The conductive layer on the front of the dielectric panel may be formed on the front surface of the panel. In this embodiment, the conductive layer performs a capacitive coupling

  with the electrodes of the back surface of the panel.

  This capacitive coupling can be modified by applying an electrical charge to the conductive layer, for example by touching or grounding the conductive layer, and this coupling modification can be used to produce a signal for of commutation. In a variant, the conductive layer

  may be spaced from the front surface of the dielectric panel

  but arranged so as to be brought into contact with the panel. In this arrangement, the electrodes of the rear surface of the panel are not initially capacitively coupled, but they are coupled when the conductive layer is brought into contact with the panel. As before, this modification of the coupling can be used to

  produce a signal used for switching purposes.

  For switching functions, one can

  divide the first set of electrodes into two groups.

  Reading pulses can be applied to one of these electrode groups by means of a circuit

  suitable. The other group of electrodes can be connected

  to a circuit capable of detecting the change of

  signal of this group of electrodes, as a result of a change in

  capacitive coupling between the groups of electrodes when the switch is actuated, the circuit being also capable of triggering a switching action according to this change. Alternatively, other electrodes may be provided on the back surface of the dielectric panel to resume the function of either one of the electrode groups so that, for example, read pulses may be applied to the whole set of electrodes carried by the back side of the dielectric panel and that a separate electrode can be used to

detection purposes.

  For lighting, impulses of a

  polarity are applied to one or more of the electro-

  of the first set and pulses of opposite polarity are applied to one or more of the electrodes of the second set. When an electrode of the first set receiving pulses passes over an electrode of the second set also receiving pulses, it is applied

  through the intermediate layer of phosphor

  sufficient potential to excite that subsi-

  tance and cause lighting at this point. The symbol or indication requested can therefore consist of several illuminated points, by the application of impulses

  to the appropriate electrodes of each set of electrodes.

  Generally, the first and second elongated electrode sets can contain between 20 and 40 electrodes

per centimeter.

  The reading pulses that are applied

  electrodes for switching purposes can generally

  have a voltage as low as 10 volts

  can be of one polarity or the other. It is, however,

  it is appropriate to use the same circuit to apply the read pulses and the illumination control pulses to the electrode set of the back panel of the dielectric panel. Reading impulses

  are applied at intervals between the impulses

  lighting. For example, the potential difference

  The minimum requirement for luminescence is generally 80 volts. Lighting pulses of +40 to +60 volts are therefore applied to the appropriate electrodes of a set and pulses of -40 to -60 volts are

  applied to the appropriate electrodes of the other set.

  These pulses generally have a duration of 10 to 30 microseconds, at a frequency of 0.5 to 2 kHz. of the

  read pulses of the same magnitude as the pulses

  Illumination (ie +40 to +60 volts) are applied to all the electrodes of the first set or to a group of electrodes of the first set, between the lighting pulses. These pulses generally have a duration of 10 microseconds at a frequency of

500 Hz.

  The invention will be described in more detail with reference to the accompanying drawings by way of non-limiting examples and in which: FIG. 1 is a diagrammatic view of

  exploded perspective of a switching / display device

  chage according to the invention; FIG. 2 is a cross-section of the switching / display device illustrated in FIG. 1; - Figure 3 is a section along the line III-III of Figure 2; FIG. 4 is a view similar to that

  of FIG. 3, showing a modified embodiment

  connected with the switching / display device;

  FIGS. 5 and 6 are cross sections.

  schematic diagrams showing variants of the

  switching / display circuits illustrated in the figures

1 to 4;

  FIG 7 is a cross section

  schematic of another embodiment of the

  switching / display device according to the invention; and - Figure 8 is a view similar to that

  FIGS. 3 and 4, illustrating a network of 2 x 6

  Switching / display circuits according to the invention.

  The switching / display device, illustrated in Figures 1 to 3 comprises a panel 10 made of a transparent dielectric material, for example glass. A set of elongated transparent parallel electrodes 11, made of an electrically conductive material such as tin oxide,

  is applied to the back surface of the panel 10.

  A transparent layer 12 of a conductive material is applied to the front surface of the panel 10 to extend above the set of electrodes 11 of the

back surface of the panel 10.

  A layer 13 of phosphor is applied to the rear side of the set of electrodes 11 and a second set of elongate parallel electrodes 14 is applied to the rear surface of the phosphor layer 13. The second set of electrodes 14 is disposed of to be oriented perpendicular to the first set of electrodes 11, each electrode of a game thus passing over all the electrodes

  from the other game to form a matrix of points.

  As illustrated in Figure 3, the electro

  11 have input connections 15 which can be connected to a circuit suitable for the application

  voltage pulses individually at each elec-

  trode. The electrodes 14 have similar input connections (not shown) by means of which

  they can be connected to a circuit designed to

  application of a voltage pulse of opposite polarity to that of the pulses applied to the electrodes 11, individually to each electrode 14. Generally, the phosphor layer used has a luminescence threshold of 80 to 120 volts and the applied voltage pulse at the electrodes 11 can be from to 60 volts, while the applied pulses

  electrodes 14 may be from -40 to -60 volts.

  If pulses are applied to an electrode of each of the sets 11 and 14, a potential of 80 to 120 volts is applied across the phosphor layer 13 at the point of overlap of these electrodes 11 and 14. This potential excites this portion. of the luminescent layer 13 and produces an illuminated dot. By simultaneously applying pulses to the appropriate electrodes of each set of electrodes 11 and 14, several points may be illuminated to form an inscription or symbol. registration

  or the symbol may be modified by the application of impulse

  at different electrodes of the games 11 and 14.

  Generally, these light pulses have a duration of 10 to 30 microseconds and can be applied to the electrodes at a frequency of 0.5 to 2 kHz, while

  the display element is lit or illuminated.

  For switching, the electrode set 11 is divided into two groups X and Y, as shown in Fig. 3. The group Y has a set of output connections 16 through which it can be connected to a suitable detection circuit. Reading pulses can also be applied simultaneously to all electrodes 11 of group X and these

  are then placed in capacitive coupling, via

  of the conductive layer 12, with the electrodes 11il of the group Y and an output pulse is therefore transmitted to the electrodes 11 of the group Y. This pulse

  output can be detected by the detection circuit.

  To actuate the switch, an electric charge is applied to the conductive layer 12, for example by a person touching this conductive layer 12. This charge reduces the capacitive coupling between groups X and Y of the electrode set 11 and therefore reduces the signal present on the electrodes 11 of the group Y. This reduction of the signal can be sensed by the detection circuit and used to perform a

switching.

  For the sake of convenience, the circuit for applying illumination pulses to the electrodes 11 may also be used to apply the read pulses but, instead of applying individual pulses to the electrodes 11, as is necessary for the purposes of lighting circuit, the circuit is designed to apply pulses simultaneously to all the electrodes 11 of the group X. These pulses

  readings are applied between the light impulses

  and generally have a duration of the order of 10 microseconds at a frequency of 500 Hz. Since no pulse is applied to the electrodes 14 when the read pulses are applied to the electrodes 11, the potential established across the layer of phosphor does not reach the illuminance threshold and, therefore, the display is not affected. The switching / display device described above provides a display that can be modified as desired. The switch can therefore be used as a multi-function programmable switch, the display being designed to change depending on the operation of the switch or in response to the actuation of other switches belonging, for example, to a switch network. switching devices /

similar display.

  Instead of dividing the set of electrodes 11 il into two X and Y groups as previously described, an additional electrode 20 can be provided on the rear surface of the panel 10 as shown in FIG. 4. The phosphor layer 13

  and the second set of parallel electrodes 14 are

  on the back side of the first set of electrodes 11il and the display is controlled as previously described. However, for switching purposes, read pulses are applied simultaneously to all the electrodes 11 of the set. The conductive layer 12 is extended to extend both on the set of electrodes 11 and on the electrode 20 and thus performs a coupling between the electrodes 11 and the electrode 20. The latter is connected to a suitable detection circuit so that a signal change

  when applying a charge to the conductive layer

  trice 12, can be detected and that a switch is triggered as previously described. An additional safety electrode 21 is provided on the rear surface of the panel 10, between the set of electrodes 11 and the electrode 20. This safety electrode 21 is connected to the ground in order to minimize any coupling.

  direct electrodes 11 with the electrode 20.

  The switching / display devices described above can be modified as illustrated in FIG. 5, by setting up a transparent, elastic and conductive membrane 40 in front of the conductive layer 12, said membrane 40 being spaced from the conductive layer 12 by insulating spacers 41. A person actuates the modified switching / display device by pressing the membrane 40 until it comes into contact with the conductive layer 12. The latter is then connected to the ground through the membrane 40 and the person touching the membrane, and the resulting electric charge imposed on the conductive layer 12 causes a reduction of the capacitive torque of the switch, as previously described. The movement of the membrane 40 gives

  a tactile sensation of reaction to the action-person

  the switch. The membrane 40 may be molded to form a bubble or a blister on top of the conductive layer 12 so that when it is

  pressed, it comes into contact with the conductive layer.

  trice by giving an elastic triggering sensation.

  These embodiments in bubble or blister can also serve to separate the membrane 40 from the conductive layer

12, in place of the spacers 41.

  In the switch shown in Fig. 6, a membrane 45 is formed of a transparent non-conductive elastic plastic material and is molded to form a bubble or blister 46 which extends

  above the conductive layer 12 and is separated therefrom.

  The inner surface of the membrane 45 is coated with

  transparent conductor 48 which is connected to ground. When this switch is actuated by pressing on the blister 46, the conductive layer 12 is connected directly to ground via the coating 48. The resulting change in capacitance is therefore independent of the person operating the switch, and we obtain thus a more regular variation of the signal when the switch is actuated. In addition, this form of switch can be operated by non-conductive means. When the pressure is released from the blister 46, the latter comes back abruptly away from the conductive layer 12, so that the capacitive characteristics of the switch

  return to their initial values when switching

driver is no longer operated.

  The central portion of the blister 46 may be made to form a lens 47 across

which display is magnified.

  In the switching device / display

  illustrated in FIG. 7, the arrangement of the elec-

  trodes 11 and 14 and the layer 13 of phosphor

  on the rear side of the dielectric panel is the same as that described with reference to FIGS.

  I to 3. However, instead of forming a conductive layer

  12 on the front surface of the panel 10, a coating 52 is applied to the rear surface of a blister 51 formed in a transparent, elastic and non-conductive membrane 50, placed in front of the panel 10 to extend over of the electrode group 11il and to be spaced from the front surface of the panel

  10. The conductive layer 52 is electrically insulated.

  With this embodiment, the coupling between

  groups X and Y of electrodes 11, when the switching

  is in its unactuated state, is weak or nil. Therefore, when reading pulses

  applied to group X of electrodes 11, the electrodes

  11 of the Y group do not produce output pulses, or produce only a very weak output pulse. However, when the blister 51 is pressed so that the coating 52 bears against the upper surface of the panel 10, the electrodes 11 of groups X and Y are capacitively coupled via the coating 52. A pulse of reading applied to electrodes 11 of group X

  then produces a large amplitude output pulse

  on the electrodes 11 of the group Y, and this impulse

  can be used to trigger a switch.

  This form of switch, in which the conductive layer 52 is spaced from the front surface of the dielectric panel 10, can be used with other electrode arrangements on the back surface of the dielectric panel 10, for example

  the form described with reference to FIG.

  The switches described above may be used individually, or more than one of these switches may be used together. However, this embodiment is suitable for producing a network of switching / display devices

  on a single panel, as shown in Figure 8.

  The latter shows a network of 2 x 6 switching / display devices, two rows of six switching / display devices being formed on one panel

  dielectric 30. Two sets of elongated electrodes trans-

  relative rows 31 are provided on the rear face of the panel 30. Two rows of six separate transparent electrodes 32 are also formed on the rear face of the panel

  between the sets of electrodes 31. Each set of electrodes

  of the 31 establishes a capacitive coupling with the row

  adjacent electrode 32 by means of conductive layers

  these individual transparencies 33 formed on the front surface of the panel 30. Each conductive layer 33 extends above a different one of the electrodes 32 and a portion of the adjacent set of electrodes 31. As previously described, both sets of electrodes 31 may be connected to a circuit for applying read pulses, while the electrodes 32 may be connected to a suitable detection circuit. The application of an electric charge to one of the conductive layers 33 modifies the coupling between the set of electrodes 31 and the electrode 32 covered by this conductive layer 33, and the change made to the signal present on the electrode 32 can be detected for an appropriate switching action on this

switch is performed.

  A layer of phosphor is applied to the back surface of the electrodes 31

  and 32 and two other parallel elongated electrode sets

  they are applied on the back side of the luminescent layer, as previously described. The display means of each switch can therefore

  be controlled by the application of impulses to electri-

  trodes, on each side of the

  as described with reference to the individual devices

dual switching / display.

  Similarly, switches of the form described with reference to FIG.

be made into a network.

  The switching / display devices of these networks may comprise elastic membranes in the manner described with reference to FIGS. 5 to 7. In such networks, the membranes associated with each switch are advantageously made in the form of a single sheet, for example example a sheet

  in which come from molding individual blisters-

  the 46 or 51 each associated with a switch. When the membrane carries a conductive coating, as described with reference to Figures 6 and 7, this coating can also be formed in one piece on the whole

of the leaf.

  It goes without saying that many modifications can be made to the device described and shown without departing from the scope of the invention. For example, in the network of switching / display devices, the two sets of electrodes 31 of the rear surface

  of the panel 30 may alternatively be arranged vertically

  As shown in FIG. 4 with switching / display networks of the type described above, the devices can be mounted in multiplexing under the control of a microprocessor.

  as described in British Patent No. 2,059,657.

  Finally, it should be noted that the drawings

  annexed are given only for the purpose of

  trative. They are not intended to indicate dimensions

  relative and particular thicknesses of the components.

  Generally, the thickness of the dielectric panel 10 is of the order of 3 mm, that of the luminescent layer 13 of the order of 40 microns and that of the various electrodes 11, 14, 20, 21, 31 and 32 and the layers

  conductive 12 and 33 of the order of 0.05 micrometer.

Claims (13)

  1. Switching / display device, characterized in that it comprises a transparent dielectric panel (10), a first set of parallel and elongated electrodes (11) formed of a transparent conductive material, on the rear face of the dielectric panel , a phosphor layer (13) in contact with the first set of electrodes (11), a second set of elongate and parallel electrodes (14) mounted in contact with the rear surface of the phosphor layer (13) the second set of electrodes (14) being inclined with respect to the first set of electrodes (11) so that the electrodes of one set overlap those of the other set to form a dot matrix, and a transparent conductive layer (12) formed in   front of the dielectric panel (10) and extending   above the first set of electrodes (11).   2. Switching / display device according to claim 1, characterized in that the first set of electrodes (11) is divided into two groups (X, Y), a group (X) of read electrodes designed   to be connected to means intended for their application   read pulses and the other group (Y) of detection electrodes adapted to be connected to means for pulsing them detection.   3. Switching / display device according to claim 1, characterized in that the   first set of electrodes (11) is designed to be connected   means for applying reading pulses thereto, and one or more additional transparent electrodes (20) are formed on the rear surface of the dielectric panel (10) which extends below the transparent conductive layer (12). , said further electrodes (20) being adapted to be connected to means for detecting   pulses traversing these additional electrodes.   4. Switching device / display   according to any of claims 1 to 3, characterized   in that the electrodes (11) designed to be connected to means for applying a reading pulse to them are separated from those intended to be connected to pulse detection means by a safety electrode (21) which is designed for to be connected to the ground.   5. Switching device / display   according to any one of claims 1 to 4, characterized   in that the transparent conductive layer (12) is disposed on the front surface of the dielectric panel (10). 6. Switching / display device according to claim 5, characterized in that an elastic and transparent conductive membrane (40) extends above the conductive layer (12) of which is spaced.   7. Switching / display device according to claim 6, characterized in that a non-conductive, transparent and elastic membrane (45) extends above the conductive layer (12) from which it is spaced, said membrane ( 45) having a conductive and transparent coating (48)   on its surface adjacent to the conductive layer (12).   8. Switching device / display   according to any one of claims 1 to 4, characterized   in that the transparent conductive layer (52) is spaced from the front surface of the dielectric panel   (10) and can be brought into contact with it.   Switching / display device according to claim 8, characterized in that the conductive transparent layer (52) is formed on the rear surface of a transparent conductive elastic membrane (50) which extends above the panel   dielectric (10) from which it is separated.   10. Network of switching devices /   display formed according to any one of the claims   1 to 9, characterized in that the switching / display devices are formed at a distance from one another on a common dielectric panel (30). Switchgear / display network according to claim 10, characterized in that a first set of electrodes (31) is common to   several switching / display devices.   12. Switching / display assembly   according to any one of the preceding claims,   characterized by comprising means for applying illumination pulses individually to each electrode of the first set of electrodes (11) and to each electrode of the second set of electrodes (14), means for applying reading pulses to a group of the first set of electrodes (11), and means for detecting capacitively transmitted pulses, via the conductive layer (12), to one or more other electrodes (11, 20) carried by the rear surface of the panel dielectric (10).   13. Switching / display assembly according to the   12, characterized in that the means for applying the illumination pulses individually to each electrode of the first set of electrodes (11) also serve to apply read pulses   simultaneously to a group of these electrodes.