Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H13/00—Switches having rectilinearly-movable operating part or parts adapted for pushing or pulling in one direction only, e.g. push-button switch
  • H01H13/70—Switches having rectilinearly-movable operating part or parts adapted for pushing or pulling in one direction only, e.g. push-button switch having a plurality of operating members associated with different sets of contacts, e.g. keyboard
  • H01H13/702—Switches having rectilinearly-movable operating part or parts adapted for pushing or pulling in one direction only, e.g. push-button switch having a plurality of operating members associated with different sets of contacts, e.g. keyboard with contacts carried by or formed from layers in a multilayer structure, e.g. membrane switches
• • H—ELECTRICITY
  • H03—ELECTRONIC CIRCUITRY
  • H03K—PULSE TECHNIQUE
  • H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
  • H03K17/94—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the way in which the control signals are generated
  • H03K17/965—Switches controlled by moving an element forming part of the switch
  • H03K17/975—Switches controlled by moving an element forming part of the switch using a capacitive movable element
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H1/00—Contacts
  • H01H1/0036—Switches making use of microelectromechanical systems [MEMS]
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H2219/00—Legends
  • H01H2219/002—Legends replaceable; adaptable
  • H01H2219/014—LED
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H2231/00—Applications
  • H01H2231/03—Elevator
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H2239/00—Miscellaneous
  • H01H2239/006—Containing a capacitive switch or usable as such
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H2239/00—Miscellaneous
  • H01H2239/01—Miscellaneous combined with other elements on the same substrate
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
  • H01H2239/00—Miscellaneous
  • H01H2239/052—Strain gauge

Definitions

• the present invention concerns a micromechanical press button in which a micromechanical pressure transducer produced on a silicon chip serves as switching element.
• a mechanical press button is composed of a button, of a spring transmitting the information of pressing, and of metallic contacts.
• the press button may be either a break or make switch.
• a pilot light is connected with the press button to indicate the state of the switch.
• pilot lights were incandescent bulbs, whereas nowadays light-emitting diodes are used .
• Electronic touch switches usually measure the capacitance between the switch and ground level. Any change in this capacitance triggers the switch. Switches of this type have no moving parts, and they are therefore in principle more reliable than equivalent mechanical press switches.
• the object of the present invention is to accomplish, applying said technology, a press switch which is free of the drawbacks mentioned.
• the press switch of the invention is mainly characterized in that the switching element has in part at least been formed on the same silicon chip on which the electronic circuitry receiving and interpreting the switching information has been integrated.
• the invention is based on machining and forming on a silicon chip a micromechanical switch, whereafter the requisite electronic circuitry is integrated on the same chip.
• the order ⁇ f operations may also be reversed, or both operations may be performed simul taneoulsy.
• the electronic circuitry may contain both analog and digital technics and it is implementable by one of the i ntegrated circuit manufacturing techniques known in the art (e.g. CMOS).
• the integrated press switch thus obtained has small size and it is reliable and, if desired, may be made intelligent enough to facilitate the installation and servicing work and so that the idea of decentralized control will be realized.
• the press button of the invention is not sensitive to static electric discharges, and it is well suited for mass production.
• the micromechanical push button is an a level with the traditional touch button.
• An advantageous embodiment of the press switch of the invention is characterized in that the switch element consists of a condensertype, capacitive pressure transducer with vacuum or air insulation, known in itself in the art, and produced in a silicon chip b machining and in which at least the thin condenser plate bending under effect of switch pressing is part of the same silicon chip on which said electronic circuitry has been integrated. It is thus understood that in this case the operation of the switch it. based on monitoring the change of capacitance.
• the switch element consists of a thin area produced by machining in a way known in itself in a piece of silicon and on the margins, or in the centre, of which impurity atoms have been processed to form a strain gauge bridge, and where the area bending under effect of switch pressing is part of the same silicon chip on which said electronic circuitry has been integrated.
• the operation of the strain gauge bridge may be based on the so-called piezoresistive phenomenon, and the processing may be carried out in well-known manner by diffusion or by ion planting. In this case, pressing the button causes the bridge to be unbalanced.
• the switch is particularly appropriate to be used in connection with lifts, where a switch located on a landing level records the outside calls and a switch provided in the lift car records the inside calls and both forward the information to the lift control system and govern the light-emitting diodes indicating the state of the lift.
• Fig. 1 presents the principle of the press switch, according to an embodiment of the invention
• Fig. 2 presents the principle of the press switch, according to another embodiment of the invention.
• Fig. 3 shows the press switch of the invention, seen from one side
• Fig. 4 presents, in the form of a block diagram, the call button system of a lift, implemented as taught by the invention
• Fig. 5 presents a practical embodiment of the call button system of Fig. 4.
• Fig. 1a the principle of a capacitive pressure transducer is shown.
• the silicon chip 1 has been machined a two-sided diminished portion 2, which constitutes one of the two condenser plates.
• the other, similarly machined (not shown), or smooth, condenser plate 3 is connected with the afore-mentioned plate so that in the space 4 between them remains air or vacuum.
• the silicon disks 1 and 3 are insulated, at the point where the condenser is formed, with a layer of insulating material 5.
• changes of pressure move the condenser plates closer to each other or away from each other, whereby its capacitance changes.
• Fig. 1b presents the equivalent circuit of this structure.
• Fig. 2a is shown the surface configuration of a piezoresistive resistance bridge 6.
• the bridge is processed on a silicon disk by diffusion or by ion planting. It is advantageous to machine in the silicon disk, at the site of the resistance bridge 6, a similar diminished portion as shown in Fig. 1a.
• all resistances R1-R4 of the bridge are equal.
• the characteristic resistance values of the resistances R1-R4 then change proportionally to the mechanical stresses present in them, whereby the resistance bridge goes out of balance, and this is measurable in a well-known manner, for finding the amount of pressure.
• Fig. 2b is shown the equivalent circuit of the bridge 6.
• a press switch comprising a front panel 7, to which an elastic press diaphragm 8 is affixed. Under the diaphragm 8 is provided a pressure limiter 9, which prevents excessive pressure from reaching the silicon pressure transducer, and a press switch hybrid circuit 10, affixed to the pressure limiter 9.
• the operation of the switch is as follows.
• the pressing information is transmitted through the press diaphragm 8 e.g. to a capacitive silicon pressure transducer located in the hybrid circuit 10.
• the electronics on the circuit board, controlled by the transducer then carries out the requisite functions for creating the switch function and for forwarding the pressing infor mation, as described in the example following later on.
• Fig. 4 is presented the block diagram of a press switch system intended for lift application, comprising the following principal components: 3 capacitive or piezoresistive silicon pressure transducer 11, pressure measuring electronics 12, intelligent holding and communications logics 13, a driver 14 for the light-emitting diodes 15, and the lift interface adapter 16. The change of pressure is recognized with the aid of the pressure measuring electronics 12.
• the holding circuit 13 records the call, and its communication logics transmit the respective information in serial or parallel format through the interface adapter 16 to the lift control system 17, whereupon the control system accepts/rejects the call and transmits an acknowledgement back through the interface adapter 16 to the holding and communications logics 13. If the call was accepted by the lift control system, the light-emitting diodes 15 are lighted through the driver 14. Upon serving the call, the control system transmits a call annulling command through the interface adapter 16 to the holding and communications logics 13.
• Fig. 5 is depicted a practical embodiment of the press switch system of Fig. 4.
• The-unit shown in the figure is a lift call button station for placement on a landing level, composed mainly of two press switches 18 and two arrows 19 indicating the direction of the call that was recorded.
• the unit is shown partly sectioned so that in the upper part is seen the outer housing of the station with its press-switch press diaphragm 20, and below can be seen the whole press switch station 18, mounted on a ceramic base 21.
• the base may equally consist of a plate made of another durable special material, such as epoxy for instance.
• the switch itself bears the reference numeral 22 and in its centre can be distinguished the pressure transducer 23.
• the electronics integrated on the same piece of silicon with the pressure transducer, has not been depicted, nor has the pressure limiter of the switch.
• the arrow symbol 19 assembled of light-emitting diodes has been mounted on the same ceramic base 21 together with the press switch 22.
• Reference numeral 24 indicates the supply voltage filter, which eliminates the ripple and interference peaks from the voltage supplied to the switch, and reference numeral 25 indicates the interface over which the call button station communicates with the lift control system.
• the respective light-emitting diode arrow 19 lights up, after the lift control system has first accepted the call and taken steps to serve it.

Landscapes

• Push-Button Switches (AREA)
• Elevator Control (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=8522108

Family Applications (1)

Country Status (3)

Cited By (2)

Families Citing this family (3)

Citations (3)

Family Cites Families (1)

• 1986
  • 1986-02-06 FI FI860549A patent/FI82332C/fi not_active IP Right Cessation
• 1987
  • 1987-02-05 WO PCT/FI1987/000019 patent/WO1987004878A1/en unknown
  • 1987-02-06 DE DE19873703666 patent/DE3703666C2/de not_active Expired - Fee Related

Patent Citations (3)

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