DE102021125967A1 - electronic input device - Google Patents

Abstract

An electronic input device comprises a frame (16) and a touch-sensitive display unit which is arranged on the frame (16) and is designed to recognize a user's touch as an input. At least one force sensor (42) is arranged on the frame (16), which is designed to detect a force exerted on the display unit when the user makes an entry and to provide a corresponding electrical signal. The force sensor (42) is electrically connected via at least one signal line (46, 48) to a connection element (36) arranged on the frame (16) and the signal line (46, 48) is printed at least in sections on the frame (16), integrated in a flexible printed circuit board glued to the frame (16), integrated into the frame (16) as an injection-molded circuit carrier, and/or at least partially in the frame (16) or in a lacquer layer or adhesive layer (30 , 34) is embedded.

Description

The invention relates to an electronic input device.

In the case of electronic input devices, an input from a user is usually recognized by the input device and a corresponding electrical signal is output, for example to a central electronic control system which controls the input device.

Typical examples of such input devices are touch screens (also known as touch screens), which use a resistive, capacitive or inductive panel to detect a user touch and emit a corresponding electrical touch signal that also includes information about the position of the touch screen touch.

A position or an area of the user's input on the input device can therefore be determined on the basis of the output electrical signal.

In the case of input devices in motor vehicles in particular, it is advantageous for the force of the touch to be determined in addition to touching the input device. In this way, for example, intentional touching can be distinguished from unintentional touching of the input device.

For this purpose, input devices are known from the prior art that additionally have a force sensor or multiple force sensors that detect the force exerted on the input device.

In particular, the electrical connection of the at least one force sensor poses a challenge.

It is therefore the object of the invention to enable simple electrical contacting of the force sensor.

The object is achieved by an electronic input device which has a frame and a touch-sensitive display unit which is arranged on the frame and which is designed to recognize a touch by a user as an input. In this case, a force sensor is arranged on the frame, which is designed to detect a force exerted on the display unit when the user makes an input and to provide a corresponding electrical signal. The force sensor is electrically connected via a signal line to a connection element arranged on the frame, and the signal line is printed at least in sections on the frame, integrated in a flexible circuit board glued to the frame, integrated into the frame as an injection-molded circuit carrier and/or into the frame or a embedded on the frame located layer of paint or adhesive layer.

The basic idea of the invention consists in arranging the signal line of the force sensor in a compact manner on the frame and leading it to a connection element via which the force sensor can be connected to a central control circuit board. The signal line is at least partially applied to the frame, in particular printed on it, integrated in a flexible printed circuit board glued to the frame, integrated into the frame as an injection-molded circuit carrier and/or embedded in the frame or in a layer of lacquer or adhesive layer located on the frame. In this way, a signal line with a smaller diameter can be used, at least in the corresponding sections, since there is no need for surrounding electrical insulation. Cables laid loosely on the frame are also superfluous.

The display unit displays a graphical interface via which the user can interact with a computer program that controls the display unit. The computer program is implemented, for example, on a microprocessor of the central control electronics, such as the control board.

Information for the user is thus displayed on the display unit and the user can make inputs by touching operating elements or generally information displayed on the display unit.

For example, the display unit is a capacitive display unit.

The electronic input device is connected to the control board via the connection element, which is usually manufactured separately from the input device and is connected to it when the input device is inserted into the corresponding product or into the corresponding device.

In a motor vehicle, the input device is typically a component that is supplied and only connected to the control circuit board via the connection element when the input device is installed in the motor vehicle.

Accordingly, the electrical signal provided by the force sensor is transferred to the control board via the connection element.

The computer program implemented in the processor or the microprocessor then only recognizes the user's input if the user presses on the display unit with a certain minimum force.

For example, a corresponding threshold value is stored on the control circuit board, for example a minimum voltage that must be present on the signal line.

One aspect of the invention provides that the signal line is completely printed onto the frame, integrated into a flexible printed circuit board glued to the frame, integrated into the frame as an injection-molded circuit carrier and/or embedded into the frame or into a layer of lacquer or adhesive layer located on the frame is. In this way, the connection element can be contacted in a particularly compact manner.

In configurations in which the signal line is printed on, this signal line can additionally be protected from vibrations and the effects of strong forces by an adhesive applied to the printed line or by the frame itself.

The force sensor can also be connected to the connection element via at least one power line. In this case, the power line is printed at least in sections on the frame and/or embedded in the frame. This means that the power is also supplied via the frame. This enables a very compact configuration of the input device.

In general, the power line can also be completely printed onto the frame, integrated into a flexible printed circuit board glued to the frame, integrated into the frame as an injection-molded circuit carrier and/or embedded into the frame or into a layer of lacquer or adhesive layer on the frame.

An electrical voltage can be applied to the force sensor via the energy line and a voltage can be tapped off via the signal line, the value of which is characteristic of the deformation of the force sensor, i.e. characteristic of the force applied to the display unit.

In some configurations, a thin insulation layer can be provided on the signal lines and/or on the power lines, for example as a coating that can be applied in a dip coating process. Thus, in particular, crossing of the signal lines or power lines can be made possible.

In those variants in which the signal line and/or the power line is/are designed as an injection-molded circuit carrier (MID, English: Molded Interconnect Device), this can in particular be a three-dimensional injection-molded circuit carrier. Crossings of the signal and power lines can also be implemented advantageously by means of an embodiment as a three-dimensional injection-molded circuit carrier.

For example, the force sensor is a strain gauge that registers an elongation, ie an extension or compression, of a section of the frame. Strain gauges make it possible to measure even small forces.

Of course, the force sensor can also have more than one strain gauge.

For example, the at least one strain gauge is embodied in a Wheatstone measuring bridge. In this way, the sensitivity of the force sensor is further improved and external influences such as temperature fluctuations can be reduced.

It is conceivable that the measuring bridge is designed as a half bridge (with two strain gauges and two resistors) or as a full bridge (with a total of four strain gauges).

In this case, the force sensor is connected to the connection element via a first signal line, a second signal line, a first power line and a second power line.

In this case, all signal lines and all power lines are advantageously completely embedded in the frame or printed onto the frame.

In other words, a signal line or a power line can be printed onto the frame in a first section and otherwise embedded in the frame. A mixture of embedded sections and printed sections is therefore conceivable.

In order to enable a precise measurement of the force exerted, the frame can have a measuring bar which is fixedly connected to the frame at one end and is in contact with another component of the input device at the other end. In this case, the force sensor is arranged on the measuring beam or is formed in the measuring beam. A force exerted on the display unit thus results in the measuring bar being stretched between the first end and the second end or is compressed. This stretching or compression is in turn measured by the force sensor, ie a corresponding electrical signal is provided and the force exerted on the display unit is accordingly recorded.

The additional component can be the display unit.

In this case, the force exerted on the display unit acts directly on the measuring bar, so that the force acting on the display unit leads directly to a stretching of the measuring bar.

It can be provided that the measuring bar extends in a recess open on one side at the edge of the measuring frame or that the bar extends within a window of the measuring frame. In this way, the measuring bar is integrated into the measuring frame.

A further aspect of the invention provides that the distance between the two ends of the bar is greater than the thickness of the measuring bar.

The thickness designates the extension of the measuring bar in a direction perpendicular to the input surface of the input device.

For example, the spacing is at least 3 times the thickness.

In other words, the measuring bar is narrow and a comparatively small force already leads to a measurable stretching of the measuring bar.

The measuring bar can be prestressed in the direction of the further component of the input device. If there is no force acting on the display unit, the measuring bar is already stretched and a small force acting on the display unit already leads to a measurable stretching of the measuring bar.

A fastening section which extends away from the measuring bar perpendicularly to the measuring bar can be formed on the measuring bar. The measuring bar is in contact with the further component of the input device via the fastening section. In this way, the measuring bar is supported on the further component and a force acting on the display unit is completely transferred to the measuring bar. The fastening section can also be used to fasten the further component to the frame. For example, the display unit can be fastened to the frame by means of the fastening sections.

For example, the measuring bar is glued to the further component via the fastening section and/or connected to it in a positive or non-positive manner.

In one embodiment of the invention, a further force sensor is arranged on the frame, which is electrically connected to the connection element via a further signal line. In this case, the additional signal line is printed at least in sections, in particular completely, on the frame and/or embedded in the frame. In this way, several force sensors can be electrically connected via a connection element. It is therefore no longer necessary to provide connecting elements for each force sensor.

The further signal line can be formed separately from the (first) signal line. In this case, the area in which a force is exerted on the display unit can also be identified.

Alternatively, the additional signal line can also be electrically connected to the (first) signal line. In this way, the number of lines required is reduced.

If a Wheatstone measuring bridge is used, then all of the first and all of the second signal lines are formed separately from one another or are formed as a common first and second signal line. The first and second power line is preferably always designed as a common first and second power line.

It can be provided that the frame has a number of measuring bars corresponding to the number of force sensors and that a corresponding force sensor is arranged or formed on or in each measuring bar. In this way, the force with which the user acts on the display unit is measured at many points on the frame.

In one embodiment of the invention, the input device has a second connection element, with at least one force sensor being electrically connected to the first connection element and at least one force sensor being electrically connected to the second connection element. In this way, various boundary conditions can be implemented through the design of the control board. In addition, the overall length of laid cables is reduced.

The frame and the display unit can be of rectangular design, with at least one force sensor being arranged on each side of the frame. The force sensors are thus evenly distributed and a force acting on the display unit at one Any position of the display unit can be detected by at least one of the force sensors.

For example, the force sensors are evenly distributed along the frame, such as centered on each side of the frame.

In order to achieve an even higher detection sensitivity, at least two force sensors can be arranged on each long side of the rectangular frame. In this embodiment, the frame has a total of six force sensors.

In practice, it has been found to be advantageous that the distance between the force sensors on the long side is 1.5 to 2.5 times the length of the distance between the force sensors and the adjacent short side.

In particular, the distance between the force sensors on the long side is twice the length of the respective distance to the adjacent short side.

In one embodiment of the invention, the frame is made of plastic and is injection molded. The signal line or the signal lines is or are injected into the frame, laid in grooves of the frame or embedded in the frame by ultrasonic wire embedding. Above all, the injection, the groove(s) or the ultrasonic wire embedding allows several signal lines to be positioned at different depths of the frame, so that many lines can be integrated into the frame.

In particular, all of the first and second signal lines and/or all of the first and second power lines can be injected into the frame made of plastic, placed in grooves in the frame, or embedded in the frame by ultrasonic wire embedding.

Of course, different combinations of the embedding processes are also conceivable.

For example, the power lines can be placed in grooves in the frame and the power lines injected into the frame or embedded in the frame by means of ultrasonic wire embedding. The power lines can also be integrated into the frame as an injection-moulded line carrier.

So that good force transmission of the force applied to the display unit to the measuring bar is ensured, the measuring bar can be designed in one piece with the frame.

For example, the frame and the molded measuring bar are an injection molded part. The force sensor can be injected into the measuring beam.

In order to provide an inexpensive input device, the display unit may comprise an LCD unit which is integrally attached to the frame.

For example, the LCD unit is glued to the frame with an adhesive tape.

In one embodiment, the input device has a rear frame that includes a backlight unit (also known as a backlight unit). The frame is attached to the rear frame at least in sections. The frame is therefore arranged spatially between the display unit and the rear frame.

In this case, the frame acts as a kind of measuring frame. The meter bar is in contact with the rear frame and a force applied to the display unit is transmitted to the meter bar through the frame.

In other words, the additional component can also be the measuring frame.

An air gap can be formed between the rear frame and the frame, or the rear frame can be attached to the frame over the entire circumference of the frame by means of an elastic intermediate layer, in particular an adhesive tape.

Furthermore, an elastic intermediate layer, in particular an adhesive tape, can also be provided between the rear frame and the display unit.

The purpose of the backlight unit is to enable the corresponding images to be displayed on the LCD unit. For this purpose, the liquid crystals in a liquid crystal display are controlled in such a way that they influence the direction of polarization of the light of the backlighting unit.

In some configurations, the display unit is alternatively designed to be self-illuminating and in particular comprises a light-emitting diode arrangement, for example an arrangement with organic light-emitting diodes, OLED.

Likewise, an LED arrangement based on inorganic materials, such as a micro-LED arrangement, can be provided.

Furthermore, a mini-LED arrangement can also be provided, which combines an LCD unit with an integrated LED arrangement as background lighting.

Furthermore, a fluorescent display unit can be provided.

In order to enable the at least one measuring beam to be fastened in a non-positive manner, the rear frame can have a fastening opening. The at least one measuring bar is attached to the rear frame via the attachment section and the attachment opening.

For example, the attachment section has a collar in the area of the second end, which is pushed through the attachment opening in the axial direction when the measuring bar is in the attached position on the rear frame. The measuring beam is then attached to the rear frame via an attachment element which is arranged axially between the collar and the attachment opening. In this case, the measuring bar is detachably attached to the rear frame.

Alternatively, the measuring bar can have fastening extensions in the area of the second section, which can be moved relative to one another, the fastening extensions being pushed through the fastening opening in the fastened position of the measuring element and engaging an area of the rear frame surrounding the fastening opening. In other words, the measuring bar is attached to the rear frame with a kind of clip connection. In this way, the measuring bar can simply be plugged into the rear frame.

In order to ensure precise positioning of the measuring bar relative to the fastening opening, a stop can be formed on the measuring bar, which rests on the rear frame when the measuring bar is in the fastened position.

In one embodiment of the invention, the connection element or elements is or are a flexible printed circuit board. The flexible printed circuit board ensures a high level of flexibility when making contact with the central control electronics.

Alternatively, the connection element or elements can be a plug-in connection element.

For example, the display unit is attached to a first side of the frame and contact can be made with the plug connection element from a second side arranged opposite to the first side. This allows for a simple plug-in connection to the control board.

It can be provided that the plug connection element can be contacted with a control circuit board when the rear frame is fastened. In this way, the electrical contact is routed from the frame to the rear frame.

For example, for this purpose the rear frame has a recess or cutout in the area of the plug-in connection element, via which contact can be made with the plug-in connection element.

Alternatively, a plug-in connection element adapted to the plug-in connection element can be formed on the rear frame, with the plug-in connection element being plugged into the plug-in connection element and being electrically contactable via the plug-in connection element.

A further aspect of the invention provides that the plug connection element has at least one via which extends from the first side to the second side of the frame. The force sensor is electrically connected to the via on the first side of the frame. The force sensor can thus be arranged in the vicinity of the display unit and the through-contact leads the electrical contact to the side on which the control circuit board is usually arranged.

For example, the via extends away from the second side of the frame, and a guide contour is disposed circumferentially around the via and extends away from the second side of the frame. In this way, the insertion of a connecting plug on the plug-in connection element is simplified and an improper application of force to the via, ie the pins protruding from the second side, is prevented.

The display unit can have a flexible printed circuit board, which is guided to the outside via a guide area in the frame. In this case, the flexible printed circuit board is accommodated in the guide area, in particular without force, so that display errors on the display unit are avoided. In addition, guiding the printed circuit board to the outside via the guiding area enables simple contacting of the display unit to a central control board.

For example, the guide area is a recess in the frame.

It is conceivable that the frame has a stabilization area in the area of the guide area having. In this way, the frame is reinforced in the area of the guide area.

In a further embodiment of the invention, the frame and the display unit can be round or rounded, with at least one force sensor being arranged on the frame. For example, three force sensors can be arranged along the frame. The force sensors can in particular be evenly distributed and a force acting on the display unit at any position of the display unit can be detected by at least one of the force sensors.

The display unit can have a flexible printed circuit board, which is guided to the outside via a guide area in the frame. In this case, the flexible printed circuit board is accommodated in the guide area, in particular without force, so that display errors on the display unit are avoided. In addition, guiding the printed circuit board to the outside via the guiding area enables simple contacting of the display unit to a central control board.

For example, the guide area is a recess in the frame.

It is conceivable that the frame has a stabilization area in the area of the guide area. In this way, the frame is reinforced in the area of the guide area.

• - 1 eine perspektivische Seitenansicht einer erfindungsgemäßen Eingabevorrichtung in einer ersten Ausführungsform,
• - 2 eine Seitenansicht der Eingabevorrichtung der 1 ohne einen Abdeckrahmen,
• - 3 eine Draufsicht auf einen Rahmen der Eingabevorrichtung der 1,
• - 4 einen schematischen Schaltplan von Kraftsensoren, die am Rahmen der 3 angeordnet sind,
• - 5 eine perspektivische Seitenansicht der Eingabevorrichtung der 1 im Bereich einer Aussparung des Rahmens,
• - 6 ein Detail B der 5 in einer Seitenansicht,
• - 7 ein Detail A der 3 in einer Draufsicht,
• - 8 eine Schnittansicht eines Anschlusselements der 7 entlang der Schnittlinie VIII-VIII in 7,
• - 9 das Anschlusselement der 8 in einem befestigten Zustand an einem Verbindungssteckelement,
• - 10 eine Ansicht von unten auf eine weitere Ausgestaltung der Eingabevorrichtung der 1 bis 9,
• - 11 eine Draufsicht auf einen Teil des Rahmens der Eingabevorrichtung in einer weiteren Ausgestaltung,
• - 12 eine weitere Ausführung der Befestigung eines Messbalkens an einem Hinterrahmen der Eingabevorrichtung in einer Schnittansicht,
• - 13 eine weitere Ausgestaltung des Messbalkens in einer perspektivischen Ansicht,
• - 14 eine weitere Ausführung des Anschlusselements am Rahmen in einer Draufsicht,
• - 15 eine Schnittansicht des Anschlusselements der 14 entlang der Schnittlinie XV-XV der 14,
• - 16 eine zweite Ausführungsform der erfindungsgemäßen Eingabevorrichtung in einer perspektivischen Ansicht,
• - 17 eine Draufsicht auf einen Rahmen einer erfindungsgemäßen Eingabevorrichtung in einer dritten Ausführungsform,
• - 18 eine Draufsicht auf einen Rahmen einer erfindungsgemäßen Eingabevorrichtung in einer vierten Ausführungsform,
• - 19 in einer Seitenansicht eine erfindungsgemäße Eingabevorrichtung gemäß einer fünften Ausführungsform,
• - 20 einen Rahmen der Eingabevorrichtung der 19 in einer perspektivischen Ansicht, und
• - 21 in einer perspektivischen Ansicht einen Teil des Rahmens der 19 und 20.

Further features and advantages of the invention result from the following description and from the accompanying drawings, to which reference is made below. In the drawings show:

• - 1 a perspective side view of an input device according to the invention in a first embodiment,
• - 2 a side view of the input device of FIG 1 without a cover frame,
• - 3 a plan view of a frame of the input device of FIG 1 ,
• - 4 a schematic circuit diagram of force sensors attached to the frame of 3 are arranged
• - 5 a perspective side view of the input device of FIG 1 in the area of a recess in the frame,
• - 6 a detail B the 5 in a side view,
• - 7 a detail A the 3 in a top view,
• - 8th a sectional view of a connecting element 7 along section line VIII-VIII in 7 ,
• - 9 the connection element 8th in an attached state to a connector plug,
• - 10 a bottom view of a further embodiment of the input device 1 until 9 ,
• - 11 a plan view of part of the frame of the input device in a further embodiment,
• - 12 a further embodiment of the attachment of a measuring bar to a rear frame of the input device in a sectional view,
• - 13 a further embodiment of the measuring beam in a perspective view,
• - 14 another version of the connection element on the frame in a plan view,
• - 15 a sectional view of the connection element 14 along the section line XV-XV of 14 ,
• - 16 a second embodiment of the input device according to the invention in a perspective view,
• - 17 a plan view of a frame of an input device according to the invention in a third embodiment,
• - 18 a plan view of a frame of an input device according to the invention in a fourth embodiment,
• - 19 in a side view an input device according to the invention according to a fifth embodiment,
• - 20 a frame of the input device 19 in a perspective view, and
• - 21 in a perspective view a part of the frame 19 and 20 .

1 FIG. 1 shows an electronic input device 10 that includes a cover frame 12, a touch-sensitive display unit 14, a frame 16, and a back frame 18. FIG.

In the design of 1 the input device 10 is rectangular. Accordingly, the display unit 14, the frame 16 and the rear frame 18 are rectangular.

The cover frame 12 frames the display unit 14 and covers part of the display unit 14 away. In this case, the cover frame 12 defines an area 20 in which a user can make an entry on the display unit 14 .

The display unit 14 includes an LCD unit 22 (also liquid crystal screen, LCD panel) via which the user can make an input. More specifically, a user touches a cover glass of the LCD unit 22.

The LCD unit 22 is illuminated by a backlight unit 24 ( 2 ) illuminated.

In the first embodiment, the backlight unit 24 is integrated into the rear frame 18 .

In general, the backlight unit 24 can also be integrated in the frame 16 . In this case, the input device 10 does not have a rear frame 18 .

Information 26 , for example a button, is displayed on the display unit 14 in a manner known per se. Since the display unit 14 is touch-sensitive, touching the display unit 14 by a user is registered and the user can make an entry on the input device if he presses on the corresponding information 26, i.e. touches the display unit 14 in the area of the information 26 displayed.

As schematically in the 2 shown, the frame is arranged spatially between the display unit 14 and the rear frame 18 and is integrally connected to the display unit 14 and the rear frame 18 .

More specifically, the frame 16 is bonded to the display unit 14 on a first side 28 by a first layer of adhesive 30 and to the rear frame 18 on a second side 32 by a second layer of adhesive 34.

In other words, a planar adhesive surface is formed on the first side 28 and on the second side 32 .

For example, the adhesive layers 30, 34 are formed by an adhesive tape.

In the first embodiment, the frame 16 is therefore firmly connected to the display unit 14 and the rear frame 18 .

On the frame 16 is a connecting element 36 ( 3 ) is formed and the frame 16 has recesses 38 on the inside, in each of which a measuring bar 40 with a force sensor 42 extends.

The force sensors 42 are therefore arranged in the corresponding recesses 38 . At least one force sensor 42 is formed on each side of the frame 16 .

More precisely, the force sensors 42 are arranged centrally on the short sides of the rectangular frame 16 and two force sensors 42 are arranged on the long sides of the rectangular frame 16 .

Along the long side of the rectangular frame 16, the force sensors 42 are positioned at a certain distance from each other. The distance d ₁ of the force sensors 42 to one another, measured from the center of the force sensors 42 or the center of the respective measuring beam 40, is twice the distance d ₂ of the force sensors 42 to the corresponding outer edge of the adjacent short side.

In other words, the ratio of the distances d ₁ to d ₂ is 2:1.

In general, the distance d ₁ can also be 1.5 to 2.5 times the distance d ₂ .

The force sensors 42 are electrically connected to a connection point 44 and to the connection element 36 via the connection point 44 and signal lines 46 , 48 and power lines 50 , 52 .

All signal lines 46, 48 and all power lines 50, 52 in the embodiment of FIG 1 integrated into the frame by means of ultrasonic wire embedding.

The signal lines 46, 48 and the power lines 50, 52 therefore run within the frame 16.

In general, the signal lines 46, 48 and the power lines 50, 52 can also be injected into the frame 16 (in this case the frame is made of plastic), inserted into corresponding grooves of the frame or printed on the frame.

Provision can also be made for the signal lines 46 , 48 to be printed onto the frame 16 and for the power lines 50 , 52 to be inserted into corresponding grooves in the frame 16 .

Furthermore, the signal lines 46, 48 and the energy lines 50, 52 can be integrated in a flexible printed circuit board glued to the frame 16 be integrated as an injection-molded circuit carrier in the frame 16 in a lacquer layer located on the frame 16 or embedded in one of the adhesive layers 30, 34.

In general, any combination of the options mentioned for arranging the signal lines 46, 48 and the power lines 50, 52 on the frame 16 are also conceivable.

Each connection point 44 includes contacts 54, namely a first contact 54.1, a second contact 54.2, a third contact 54.3 and a fourth contact 54.4. For reasons of clarity, the contacts 54.1 to 54.4 are only for one of the connection points 44 in the 3 drawn.

The corresponding force sensors 42 are connected to each of the contacts 54.1 to 54.4 via separately formed lines. In 3 this is indicated by a line between the corresponding force sensor 42 and the associated connection point 44 .

Of course, four separate lines extend from the connection point 44 to the corresponding force sensors 42.

All first contacts 54.1 are connected to the connection element 36 via the first signal line 46, all second contacts 54.2 via the second signal line 48, all third contacts 54.3 via the first power line 50 and all fourth contacts 54.4 via the second power line 52.

In other words, the force sensors 42 are supplied with electrical energy via the energy lines 50, 52 and transmit an electrical signal to the connection element 36 via the signal lines 46, 48.

As in the schematic of 4 is shown schematically, each force sensor 42 includes a total of four strain gauges 56, which are interconnected in a ring or a square (Wheatstone bridge). For reasons of clarity, only the strain gauges 56 of the in 4 force sensor 42 shown on the right are provided with corresponding reference symbols.

In the design of 4 each force sensor 42 is therefore designed as a full bridge.

In general, all or only some of the force sensors 42 can also be designed as a half-bridge.

A supply voltage (Vcc) relative to ground is applied to each force sensor 42 via the power lines 50, 52, and an electrical signal S ₁ , S ₂ , i.e. a voltage that is characteristic of a deformation of the strain gauges 56, is tapped off via the signal lines 46, 48.

All force sensors 42 have common first and second signal lines 46, 48. Therefore, the deformation cannot be assigned to a specific force sensor 42, but the presence of a deformation can only be measured in general.

The force sensors 42 are accordingly designed to detect a stretching, ie a compression or a stretching, of the corresponding measuring beam 40 .

Each measuring bar ( 5 ) a measuring section 58 in which the corresponding force sensor 42 is arranged, and a fastening section 60 which is formed onto the measuring section 58 and extends perpendicularly away from the measuring section 58.

The measuring bar 40 is firmly connected to the frame 16 at a first end 62 . More specifically, the scale bar 40 is integrally formed with the frame 16 at the first end 62 .

However, the measuring bar 40 can also be a separate part that is firmly connected to the frame 16 . In this case, the measuring beam 40 is in particular not detachably connected to the frame 16 .

For example, the frame 16 is made of plastic and the recesses 38 and the measuring bar 40 are formed on the frame 16 by means of an injection mold.

At a second end 64, which is formed by the fastening section 60, the measuring bar 40 is in contact with a further component 66 of the input device 10. In the first embodiment, the additional component 66 is the rear frame 18.

In other words, the measuring beam 40 is only attached to the frame 16 at one end and not at the other end.

In this case, the measuring bar 40 is designed to be relatively thin. This means that the thickness b of the measuring bar 40 is smaller than the length I of the measuring bar 40 ( 6 ).

In particular, the ratio of the length l to the thickness b of the measuring beam 40 is more than 3:1. The measuring bar 40 is therefore more than three times as long as it is wide.

When a force F is applied by a user to the display unit 14, the frame 16 is deformed. After the measuring bars 40 are attached to the rear frame 18 via the corresponding fastening sections 60, the measuring sections 58 of the measuring bars 40 deform depending on the position of the force F and the amount of the force F, ie the force exerted.

In one variant, the attachment portions 60 can extend towards the rear frame 18 and bear against or be connected to it. In such variants, it is advantageous if the second adhesive layer 34 between the frame 16 and the rear frame 18 is comparatively soft, while the first adhesive layer 30 between the display unit 14 and the frame 16 is comparatively hard.

In other words, the second adhesive layer 34 is softer, i.e. more elastic, than the first adhesive layer 30

In this manner, the adhesive layer 34 acts as a resilient member and allows movement of the display unit 14 and frame 16 toward the rear frame 18, with the frame 16 and display unit 14 moving as a unit.

Alternatively, in another variation, the attachment portions 60 may extend from the frame 16 toward the display unit 14 . In this case, the first adhesive layer 30 is chosen to be comparatively soft and acts as an elastic element, while the second adhesive layer 34 between the frame 16 and the rear frame 18 is chosen to be comparatively hard. Thus, when a force F acts on the display unit 14, a relative movement of the display unit 14 in the direction of the frame 16 and the rear frame 18 can take place, as a result of which a deformation of the measuring bar 40 is achieved. In this variant, the frame 16 and the rear frame 18 thus form a “stationary” unit, in the direction in which the display unit 14 moves under the action of the force F.

In both variants, the adhesive tape, which is arranged on the side of the frame 16 on which the force sensors 42 are arranged, acts as an elastic element. In addition, it can act as a fastener and as a seal against escaping stray light and against penetrating moisture and particles such as dust. The other, hard adhesive layer acts in particular as a fastener and as a seal.

Usually, several measuring bars 40 are measurably deformed by the force F and accordingly several force sensors 42 detect the force F on the display unit 14 and provide the corresponding signals S ₁ , S ₂ on the signal lines 46 , 48 .

The electrical signals S ₁ , S ₂ measured by the force sensors 42 are transmitted to the connection element 36 via the first and second signal line 46 , 48 ( 7 ).

The connection element 36 has connection contacts 68, via which the signal lines 46, 48 and the power lines 50, 52 are electrically contacted.

The connection contacts 68 in the first specific embodiment are in the form of plated-through holes 70 and are arranged in series. Adjacent connection contacts 68 have a spacing a ₁ , for example a spacing a ₁ of 0.5 mm.

The vias 70 extend from the first side 28 of the frame 16 to the second side 32 and away from the second side 32 .

On the second side 32 of the frame 16 in the area of the plated-through holes 70 there is also a guide contour 72 which extends away from the second side of the frame 16 and which makes it easier to insert a connector plug into the connection element 36 .

For example, a plug-in connection element 76 is formed for this purpose on the rear frame 18 ( 9 ), via which the vias 70 are connected to electrical lines 78 of the rear frame 18 .

The connection element 36 is thus designed as a plug-in connection element 74 and thus the electrical lines 78 and the signal lines 46, 48 and the power lines 50, 52 can be easily contacted via the connection element 36.

Based on 10 until 21 further refinements and embodiments of the input device 10 are explained below. The other refinements and embodiments essentially correspond to the embodiment of FIG 1 until 9 , so that only the differences will be discussed below. Identical and functionally identical components are provided with the same reference symbols.

In contrast to the first embodiment, the rear frame 18 of 10 a recess 80 via which the connection element 36 can be contacted.

To put it more precisely, a ribbon connector 82 is connected to the connection element 36 and electrically connects the connection element 36 to a control circuit board 84 .

An electrical voltage is applied to the power lines 50 , 52 via the control circuit board 84 and a microprocessor 86 evaluates the voltages provided by the force sensors 42 . Accordingly, the microprocessor uses the voltages provided to calculate the force that a user has exerted on the display unit 14 .

For example, the microprocessor 86 recognizes user input as input only if the user pressed the display unit 14 with a minimum force.

For this purpose, a corresponding threshold value, i. H. a certain minimum voltage.

In addition, the microprocessor 86 is electrically connected (not shown) to the display unit 14 and drives it.

The arrangement of the control board 84 on the back of the rear frame 18 is to be understood as an example. The control circuit board 84 is usually arranged at a suitable location on a device, for example a motor vehicle, and is electrically connected to the connection element 36 via the ribbon connector 82 .

In the design of 11 the measuring bar 40 extends within a window 90 of the frame 16 instead of in a recess 38 open on one side.

Of course, part of the measuring bars 40 can be arranged in a corresponding recess 38 of the frame 16 and the other part of the measuring bars 40 can be arranged in corresponding windows 90 of the frame 16.

In the configurations of 12 and 13 the attachment of the measuring beam 40 to the rear frame 18 is changed.

To put it more precisely, the rear frame 18 has a fastening opening 92 in which the fastening section 60 of the measuring bar 40, that is to say the measuring bar 40, is fastened.

In the design of 12 the fastening section 60 has a collar 94 at the second end 64 which is pushed through the fastening opening 92 .

The dimensions of the collar 94 are therefore smaller than the dimensions of the attachment opening 92.

Axially offset in the direction of the measuring section 58, a stop 96 is also formed on the fastening section 60, which can be seen in the embodiment of FIG 12 extends perpendicularly away from the measurement section 58 and forms a second collar, the dimensions of which are larger than the dimensions of the attachment opening 92.

Accordingly, the stop 96 does not fit through the attachment opening 92 and rests on the rear frame 18 in the attached position of the measuring beam 40 .

To fasten the measuring bar 40 to the rear frame 18 , a U-shaped fastening element 98 is additionally fastened axially between the collar 94 and the stop 96 on the fastening section 60 , for example clipped to the fastening section 60 .

The fastening element 98 bears directly against the collar 94 and additionally against a region 100 of the rear frame 18 which surrounds the fastening opening 92 on the side facing away from the frame 16 .

The fastening section 60 is thus prestressed in the direction of the rear frame 18 by the fastening element 98 . In this way, a secure attachment of the measuring bar to the rear frame 18 is ensured, so that even a small force F acting on the display unit 14 leads to a measurable deformation of the measuring bar 40 .

In the design of 13 For example, no collar 94 is formed on the attachment section 60, but attachment extensions 102 extend away from the second end 64 of the measuring beam 40. The attachment extensions 102 are movable relative to each other and relative to the attachment portion 60 . The attachment extensions are in the direction of the in 13 shown position biased.

More precisely, the attachment extensions 102 are pressed against the attachment portion 60 during the passage of the attachment extensions 102 through the attachment opening 92 . As soon as the attachment extensions 102 have been passed through the attachment opening 92, the attachment extensions 102 move away from the attachment section 60 and act as a type of barb which engage in the area 100 of the attachment opening 92 and cause movement of the measuring ball kens 40 prevent through the mounting hole.

In general, of course, the fastening section 60 can also be fastened in the fastening opening 92 via a clip connection.

Another difference in the design of the 13 is that the force sensor 42 is located within the sensing portion 58 .

For example, the force sensor 42 has already been inserted into the injection mold and is correspondingly injected into the measuring beam 40 .

The 14 and 15 show a further embodiment of the connection element 36.

In this embodiment, the connection contacts 68 are not arranged in a row but in a square. Adjacent connection contacts 68 are at a distance a ₂ from one another.

For example, the distance a ₂ is 2 mm.

In the 16 a second embodiment of the input device 10 is shown. In contrast to the first embodiment, the input device 10 in the second embodiment does not have a rear frame 18 . Instead, the backlight unit 24 is integrated into the frame 16 . In this way, the input device 10 can be made particularly compact.

In addition, the measuring bar 40 is attached to the display unit 14 at the second end 64 . Thus, the display unit 14 is the further component 66. A force F on the display unit 14 acts directly on the measuring bar 40 and the measuring bar 40 is deformed directly because of the force F.

In addition, the frame 16 is made more rigid in the second embodiment than in the first.

For example, in the second embodiment, the frame 16 is formed of metal, or a metal framework partially or fully overmolded with plastic.

Alternatively, the frame can also consist of a fiber-reinforced plastic, in particular a glass-fiber-reinforced plastic.

The 17 12 shows a third embodiment of the input device 10. In contrast to the first embodiment, the first and second signal lines 46, 48 are formed separately from one another and are embedded in the frame 16. FIG.

Thus, an independent (separate) first signal line 46 and an independent (separate) second signal line 48 lead from the connection element 36 to each force sensor 42.

In this way, the electrical signals of each force sensor 42 can be read out on the connection element 36 and therefore the area of the force effect F can also be determined.

The power lines 50, 52 are in turn formed together.

All signal lines 46, 48 and all power lines 50, 52 are completely embedded in frame 16.

Alternatively, individual or all of the signal lines 46, 48 and/or power lines 50, 52 can also be printed onto the frame 16.

A further difference is that the connecting element 36 is designed as a flexible circuit board 104 which is routed to the control circuit board 84, for example, and is plugged into a corresponding receptacle on the control circuit board 84.

In the fourth embodiment of the 18 two connection elements 36 are formed on the frame 16 . More precisely, two flexible printed circuit boards 104.

Another difference is that only one measuring beam 40 with a corresponding force sensor 42 is arranged on each side of the frame 16 .

The frame 16 therefore has only four measuring beams 40 and four force sensors 42 . In this case, two force sensors 42 are each connected to a connection element 36 .

The 19 until 21 show a further embodiment of the input device 10. For the sake of clarity was in the 19 until 21 the signal lines 46, 48, the power lines 50, 52 and the connection element 36 or the connection elements 36 are not shown.

In contrast to the previous embodiments, guide areas 106 are formed on the frame 16, via which a flexible printed circuit board 108 is guided from the LCD unit 22 to the control board 84 in each case. The flexible printed circuit board 108 is used to control the LCD unit 22.

More precisely, the flexible printed circuit board 108 is guided outwards via the guide areas 106 , then extends laterally along the frame 16 and the rear frame 18 and is electrically connected to the control circuit board 84 on the rear side of the rear frame 18 .

The representation of 19 is only to be understood as an example. The control board 84 need not be located directly on the rear frame 18 of the input device 10 .

The guide areas 106 are adapted to the flexible printed circuit boards 108 and are designed as recesses in the frame 16 in the embodiment shown. The planar adhesive surface on the first side 28 of the frame 16 is thus partially interrupted and the printed circuit boards 108 are accommodated in the guide areas 106 without any force. In particular, an input by a user on the display unit 14 does not result in a force being applied to the printed circuit boards 108.

In the area of the guide areas 106, the frame 16 has stabilizing areas 110 offset in the direction of the rear frame 18, which are offset in the direction of the rear frame 18 relative to the first side (see FIG 21 ).

In other words, the stabilization regions 110 are designed in the manner of a bridge.

The stabilization areas 110 stiffen the frame 16 in the area of the guide areas 106. In this way, an input by the user on the LCD unit 22 in the area of the guide areas 106 is reliably transmitted to the frame 16 and correspondingly detected by the force sensors 42.

Another difference is that a total of five force sensors 42 are embedded in the frame 16, for example in corresponding measuring beams 40, which are designed on the frame 16 in accordance with the previous embodiments.

Two force sensors 42, for example, are arranged on one long side of the rectangular frame 16 and three force sensors 42, for example, are arranged on the other long side.

It should be emphasized that the idea of the guide areas 106 is of course not only limited to the input devices of the previous embodiments.

Reference List

10

input device

12

cover frame

14

display unit

16

Frame

18

rear frame

20

Area

22

LCD unit

24

backlight unit

26

information

28

first page

30

first adhesive layer

32

second page

34

second adhesive layer

36

connection element

38

recess

40

measuring bar

42

force sensor

44

connection point

46

first signal line

48

second signal line

50

first power line

52

second power line

54

Contact

56

strain gauges

58

measurement section

60

attachment section

62

End

64

End

66

component

68

connection contact

70

vias

72

guide contour

74

plug connection element

76

connector plug

78

Management

80

recess

82

ribbon connector

84

control board

86

microprocessor

88

Storage

90

windows

92

mounting hole

94

collar

96

attack

98

fastener

100

Area

102

attachment extensions

104

circuit board

106

management area

108

flexible circuit board

110

stabilization area

Claims (15)

Electronic input device, with a frame (16) and a touch-sensitive display unit (14) arranged on the frame (16), which is designed to recognize a touch by a user as an input, wherein at least one force sensor (42) is arranged, which is designed to detect a force exerted on the display unit (14) when the user makes an entry and to provide a corresponding electrical signal (S ₁ , S ₂ ), the force sensor (42) being connected via at least one signal line (46 , 48) is electrically connected to a connection element (36) arranged on the frame (16), and wherein the signal line (46, 48) is printed at least in sections on the frame (16) and is integrated in a flexible printed circuit board glued to the frame (16). integrated into the frame (16) as an injection-moulded circuit carrier and/or embedded at least partially in the frame (16) or in a lacquer layer or adhesive layer (30, 34) on the frame (16). input device claim 1 , characterized in that the signal line (46, 48) is completely printed onto the frame (16), integrated into a flexible printed circuit board glued to the frame (16), integrated into the frame (16) as an injection-molded circuit carrier, and/or into the Frame (16) or in a paint layer or adhesive layer (30, 34) located on the frame (16). input device claim 1 or 2 , characterized in that the force sensor (42) is additionally connected to the connecting element (36) via at least one power line (50, 52), the power line (50, 52) being printed at least in sections, in particular completely on the frame (16), integrated in a flexible printed circuit board glued to the frame (16), integrated into the frame (16) as an injection-molded circuit carrier, and/or in the frame (16) or in a lacquer layer or adhesive layer (30, 34 ) is embedded. Input device according to one of the preceding claims, characterized in that a further force sensor (42) is arranged on the frame (16), the further force sensor (42) being electrically connected to the connection element (36) via a further signal line (46, 48). , wherein the further signal line (46, 48) is printed at least in sections, in particular completely on the frame (16), integrated in a flexible printed circuit board glued to the frame (16), integrated as an injection-molded circuit carrier in the frame (16), and/or is embedded in the frame (16) or in a layer of lacquer or adhesive layer located on the frame (16). input device claim 4 , characterized in that the further signal line (46, 48) is formed separately from the first signal line (46, 48) or is electrically connected to the first signal line (46, 48). input device claim 4 or 5 , characterized in that the input device (10) has a second connection element (36), at least one force sensor (42) being electrically connected to the first connection element (36) and at least one force sensor (42) to the second connection element (36). Input device according to one of the preceding claims, characterized in that the frame (16) and the display unit (14) are rectangular, with at least one force sensor (42) being arranged on each side of the frame (16). input device claim 7 , characterized in that at least two force sensors (42) are arranged on each long side of the rectangular frame (16). input device claim 8 , characterized in that the distance between the force sensors (42) on the long side is 1.5 to 2.5 times the length, in particular twice the length, of the distance between the force sensors (42) and the adjacent short side. Input device according to one of the preceding claims, characterized in that the frame (16) is made of plastic and is injection molded, the signal line (46, 48) and/or the power line (50, 52) being integrated into the frame (16). injected, inserted into grooves of the frame (16) or embedded in the frame (16) by ultrasonic wire embedding. input device claim 10 , characterized in that the signal line (46, 48) and/or the power line (50, 52) is embedded in the frame (16) by means of ultrasonic wire embedding in such a way that a surface of the signal line (46, 48) is partially exposed. input device claim 10 , characterized in that the signal line (46, 48) and/or the power line (50, 52) is embedded in the frame (16) by means of ultrasonic wire embedding in such a way that the surface of the signal line (46, 48) is completely covered by the plastic is surrounded. Input device according to one of the preceding claims, characterized in that the display unit (14) comprises an LCD unit (22) which is materially attached to the frame (16). Input device according to one of the preceding claims, characterized in that the input device (10) has a rear frame (18) which has a backlighting unit (24) of the display unit (14), the frame (16) being attached at least in sections to the rear frame (18). is. Input device according to one of the preceding claims, characterized in that the connection element (36) or the connection elements (36) is or are a flexible printed circuit board (104) or is or are a plug-in connection element (74).

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