DE202004003618U1 - Push button sensor as a touch or tactile switch - Google Patents

Abstract

The invention relates to a touch sensor as an electrical touch or tactile switch, characterized in that the switching and contact surface of the touch sensor is made of electrically conductive plastic.

Description

The invention relates to a push button sensor as an electrical touch or tactile switches primarily for use in the field of Low-voltage switchgear for example as a product or device switch.

Low voltage electrical switches, as a group of switchgear, are adequate known; they are classified according to different criteria, according to standard VDE0660, Part 1, after

• 1. the mechanical behavior in the switch positions: Latch, key, lock switch
• 2. the type of actuation: Hand foot-, Kicking off-, Auxiliary, remote, jump switches, contactors, switches with positive opening
• 3. the switching capacity: Empty, load, motor, power switch
• 4. the type of arc quenching: Air, oil, gas, Vacuum switch
• 5. the intended use: protection, separation, choice, conversion, tax, Limit switch, guard, limiter
• 6. the type of installation or connection: Fixed, insertable, pluggable devices.

There is also a standard Series of partly general, partly special electrical parameters for low-voltage switchgear.

Electrical latching switches can be used Actuation by pressure or tension, torsion, by touch or without contact to be served. The user / operator expects an answer via his deliberate / executed Switching action in the form of a mechanical, electrical, optical or acoustic signal. With a latching switch, the triggered switching action can visually perceived by mechanical position of the shift lever / button or felt become; the detent switches have a mechanical, electrical or optical storage of the switch position.

With the in its initial position after actuation back sweeping switch is an additional message / display via the Switch position required. The electrical push button provides a special form of switch than that the result of the switching action must be disclosed to the user. Like the electrical snap switch, there are also the above-mentioned designs for pushbuttons; Keys through Pressure, tension, torsion, touch or contactless Move.

Show latching and pushbutton switches in short-stroke design only on the short switching travel / stroke or have a mechanical, pneumatic, hydraulic or electrical translation and can by Jog mode can be operated with low pressure, tension or torsion.

With the foil or membrane switch or keyboard are thin, electrically conductive contact foils, consisting of three layers including insulating middle layer or two-layer with insulating mesh covering between the conductive layers. The switching action is done by light mechanical pressure and production of a electrical contact at the contact point between the top and bottom film; the middle film has a recess at the contact point.

With contactless switching or pushing through Light, daytime, active / passive infrared (IR), ultra violet (UV) light, induction (Hall generator, field plate), capacity (Piezo effect) or acoustics are sufficient a field change through defined movement as a switching signal at a given distance from the marked switch / button.

With the push button sensor as a touch or tactile switch must be one frictional Touch or a touch with the button with or without pressure, depending on the technical structure of the sensor execution a switching operation take place. Switching or keying is usually done logically with low performance; Function and performance are in the aftermath through logic and reinforcement defined, as well as the response signal to an executed switching operation.

According to the prior art, a number of embodiments of touch sensors of different technologies are known. In patent specification CH 693 075 A5 / DE 196 15 827.3 a push button sensor with an infrared receiver is shown, which is connected to a bus coupling unit for data exchange. The push button sensor consists of several manually operated buttons, to which switching contacts are stored; feedback is provided via separate visual displays. The design of the push button sensor is very complex, consists of many individual parts, the assembly is not easy to assemble. The keyboard structure consists of printed individual keys that determine the product design, and their hygiene is also complex.

Patent specification CH 664 831 A5 / US 476 685 has an x-element tactile matrix push button. At a 90 ° angle to each other running, parallel, mutually insulated conductors of two horizontal Levels are over at printing an isolated, horizontal, third middle layer, which at the intersection of the leads on both conductor levels, vertical, conductive pins the pressure points electrically connected to each other. The vertical Standing, conductive pins have cross-sections that change logarithmic when printed Call the electrical contact resistance. The structure of the Matrix keyboard is very complex, but it has an easy-care, smooth surface. Statements about a designed response signal are not hit.

The disclosure DE 39 14 555 A1 presents an electronic push button, consisting of elastic material with a defined electrical conductivity that is contacted such that there is a deformation of the pressure surface when the pressure changes results in a change in electrical resistance. If a line or matrix structure is built on this basis, the electronic push-button sensor with one-dimensional diode decoupling allows one- or two-dimensional direction detection. No statement was made about the product design.

The PCT registration DE 198 59 779.7 / EP 1 142 118 A1 / WO 00/39 927 discloses a push button sensor in which a fiber is connected to a transducer designed as a capacitor in such a way that contact of the free end of the fiber with an object is converted into electrical signals. The sensor also allows the registration of dynamic movements and thus the determination of the relative speed between the sensor and the object. Robotics is intended as an area of application.

The Dutch application NL C 10 02 907 describes a matrix Push button sensor consisting of pressure-sensitive, layered segments, the OHM resistance decreases as the force is applied. The matrix structure enables two-dimensional direction detection given.

The disadvantage of the presented solutions the stratification and matrix formation of the touch sensors, since the Manufacturing and assembly process too Extensively designed. The application of conductor tracks flexible circuit board material is fundamental possible, however, requires the use of expensive base materials. The visualization of the response signal to a tactile switching action can be difficult to achieve within the switching matrix. Often it should Operator interface simultaneously represent the outer surface of the device / housing.

The invention is therefore the object to avoid using a touch sensor as a touch or tactile switch to devalue the disadvantages mentioned above, its structure simple is designed so that a good ease of installation is given. Furthermore, the Insert the push button into the design language of the product. Under Hygiene aspects should be aimed at smooth, uninterrupted surfaces. The response signal to a switching operation must be user-friendly his.

This object is achieved according to the invention solved, that the Button and contact area of the push button sensor made of electrically conductive plastic is. Will the switch and contact surface, which has two connecting wires with an evaluation and power electronics is connected, changes the electrical resistance of the material of the switch and contact surface; this Material change resolves in the downstream electronics a switching action.

Another advantageous embodiment the invention is characterized in that the switching and contact surface electrically conductive, transparent plastic is executed.

The advantages achieved with the invention consist in particular in that the Button / contact area in the Housing surface of the Product design is integrated. This brings advantages for external care of the product, e.g. when used in the medical field. Furthermore the all-round conductive surface of the housing offers advantages in environmental aspects, such as electromagnetic compatibility (EMC) and electrostatic discharge (ESD) for radiation and radiation of fields.

The button / contact surface of the Push button sensor acts electrically on an evaluation electronics, which by means of logic and reinforcement Function and performance as well as the response signal to the switching operation carried out certainly. The electrical circuit is called sensitive electrical bridge performed; the push button sensor is switch-safe.

When applied in a 2-component spraying process transparent button / contact surface - if the surface of the housing is not designed to be transparent anyway - an optical response signal can be used by a light source, preferably a light-emitting diode (LED), deposit.

If the light source is provided with a light control, serves the light source above signaling additional functions, such as the lighting the button / contact area or a daylight / artificial light control or further reading / work light functionality.

Another advantageous embodiment the invention is given in that the highly transparent switch / contact surface of the Push button sensor has optical properties that can serve at the light emitted by the light source is directed / focused to make or the reverse process from the outside light by means of a / s photodiode / transistor derive a signaling in the push button sensor.

The button / contact area is inside an electrically conductive product surface, is the position of the switch / contact surface between the two connecting wires according to the rules of the electric flow field Are defined.

Another advantageous embodiment The invention lies in the production-related prefabrication the button / contact area with electrical connections as an insert.

Depending on the requirements of the push button sensor, According to a further embodiment of the invention, the switch / contact surface is geometrical shaped; the geometric shape has z. B. to the goal from one multi-step switching operation of the operator Derive algorithm in the downstream evaluation electronics.

A similar objective is pursued by a further embodiment of the invention in that the switching / contact surface made of conductive plastic has clearly defined or flowing zones of different has electrical conductivity to derive additional information for the switching operation when actuated.

The aim of the present invention is it to update the state of development of the push button sensor, the operation with increased clarity to simplify, increase operational safety, tool costs and reduce the variety of parts to make the market a modern product offer. The numerous possibilities and advantages of the embodiment of the invention are reflected in the Number of property rights claims contrary.

Claims (13)

The invention relates to a touch sensor as an electrical touch or tactile switch, characterized in that the switching and contact surface of the touch sensor is made of electrically conductive plastic. Push button sensor according to claim 1, characterized in that the Button and contact area is made of electrically conductive, transparent plastic. Push button sensor according to at least one of claims 1 and 2, characterized in that the switch / contact surface in the Housing surface of the Integrated product design is. Push button sensor according to at least one of claims 1 to 3, characterized in that the switching / contact surface is electrical on evaluation electronics, e.g. a sensitive, electrical Bridge, which works by means of logic and amplification function and performance as well as the response signal to the switching operation carried out. Push button sensor according to at least one of claims 1 to 4, characterized in that the Integration of a response signal via the completed switching operation in the button / contact area given is. Push button sensor according to at least one of claims 1 to 5, characterized in that the transparent Switch / contact area with a light source, e.g. a light emitting diode (LED), as optical response signal is stored. Push button sensor according to at least one of claims 1 to 6, characterized in that the transparent button / contact surface stored light source has a light control, its brightness levels serve to signal various functions. Push button sensor according to at least one of claims 1 to 7, characterized in that the high transparent, electrically conductive switch / contact surface optical Has properties. Push button sensor according to at least one of claims 1 to 8, characterized in that the product design surface of the Plastic housing electrically is designed to be conductive. Push button sensor according to at least one of claims 1 to 9, characterized in that the switching / contact area within given the electrically conductive product surface through electrical connections is. Push button sensor according to at least one of claims 1 to 10, characterized in that the switch / contact surface with electrical connections as Insert is manufactured. Push button sensor according to at least one of claims 1 to 11, characterized in that the switch / contact surface electrically conductive plastic for its intended use receives geometric shape. Push button sensor according to at least one of claims 1 to 12, characterized in that the switch / contact surface electrically conductive plastic for the intended use different electrical conductivities having.