Operator control unit for measuring instruments in process or automation engineering and measuring instrument having such an operator control unit

Abstract

The invention relates to an operator control unit for a measuring instrument in process or automation engineering, which operator control unit consists of at least two adjacent control panels (10a), the control panels (10a) being operated by pressing corresponding shape-variable or elastic housing regions (2a) which have corresponding capacitive sensor elements (11) arranged therebelow. The sensor elements (11) each have a first electrode (11a) as the lower plate capacitor and a counter electrode (11b) arranged parallel above the first electrode as the upper plate capacitor, and pressing one housing region (2a) causes the corresponding upper plate capacitor (11b) to approach the corresponding lower plate capacitor (11a), thus changing the capacitance. The first electrode (11a) is attached to a first carrier material (12), and the counter electrode (11b) is attached to a second carrier material (13). According to the invention, the housing regions (2a) are arranged adjacent to one another in an uninterrupted manner, and the sensor elements (11) are part of a multilayer composite printed circuit board (100) which abuts against the inner side of the housing regions (2a), wherein the composite printed circuit board (100) at least comprises: a first carrier material (12) which consists of multi-segment rigid circuit boards, with flexible intermediate pieces arranged between the segments respectively; and a second carrier material (13) in the form of a conductive layer, the two carrier materials being separated from one another via an inserted plastic layer (15), which forms a measuring chamber (17), and wherein the plastic layer (15) comprises a plurality of interruptions for forming the sensor elements (11) and separation regions (16) between the control panels (10a).

Description

Field of the Invention

[0001] The present invention relates to an operator control unit for a measuring instrument in the field of process or automation engineering and to a measuring instrument having such an operator control unit. Background Art

[0002] In automation and process engineering, sensors and measuring instruments are frequently used, which transmit measured values (such as pressure, temperature, flow rate, and distance or vibration) into an output signal representing the measured value in the form of an analog or digital current or voltage signal and provide this signal at their cable or plug connections (but sometimes also wirelessly) to a higher-level control unit (such as a PLC) for further processing.

[0003] Typical measuring instruments mainly consist of a sensor element (also called a transducer), which is used to detect the physical measurement variable of a process value and convert it into a measurement signal. In addition, an evaluation unit is provided, which is usually implemented as a microcontroller, and in this evaluation unit, the measurement signal generated by the sensor element is conditioned (i.e., amplified) and usually also already processed. On the output side, the evaluation unit is connected both to a display unit and to a communication interface, via which the conditioned measurement signal can be transmitted to the above-mentioned control unit. The current measured value is displayed on the display unit. In addition, the display unit is usually also used to set up and parameterize the measuring instrument. For this purpose, the measuring instrument also includes corresponding input options. In typical measuring instruments of the type under discussion, these input options are designed as operating keys, the actuation of which affects micro buttons. In this regard, reference is made, for example, to DE 102014206486 A1.

[0004] In addition to mechanical switches and buttons, various possibilities for operating a device by merely touching the device through an enclosing housing wall are also known. For example, magnetic actuation is known, in which a reed contact inside the device is actuated by a magnet movably attached to the outside of the housing. In addition, optical reflection actuation through a transparent housing wall (such as the glass plate of a display instrument) is known. Optical reflection actuation is often used in the field of indicators. For example, an automation device is known from DE 102005048021 B3, which can be operated locally by means of a passive infrared sensor.

[0005] However, all these switches and buttons require interrupting the housing in which, for example, a glass plate is inserted, which results in tightness problems or complex structures attached to the outside of the housing (such as in the form of a magnet).

[0006] It is known from German Patent Specification DE 102013225076 B4 to detect a keystroke by touching a sensitive surface provided on a housing wall by enclosing the housing wall (i.e., according to the calorimetric principle). In this case, the temperature change caused by touching the sensitive surface as a result of the occurring heat transport is determined.

[0007] US2013 / 0126325 A1 discloses an operator control unit for an electronic device implemented by means of a capacitive touch sensor. By pressing a deformable area of metal, the capacitance value of the capacitive sensor changes, such that a keystroke can thus be detected. However, the solution shown there can only be applied to operator control units or control panels with a very thin housing thickness. In the case of the measuring instruments discussed, which are intended for automation and process engineering, their housings must be designed correspondingly thicker and thus more stable in order to withstand often very harsh industrial conditions.

[0008] It is known from DE 102011075942 A1 an operating device for an electrical appliance. The operating device includes an uninterrupted housing area, a multi-layer conductive composite, and a plastic layer, which includes a number of interruptions and forms a measuring chamber.

[0009] It is known from US 5086652 A a touch sensor for measuring forces at a plurality of locations, wherein the individual sensors are interconnected by a flexible layer of Mylar polyester. Summary of the Invention

[0010] The object of the present invention is to provide an alternative possibility for operating a measuring instrument of the above type through a robust, enclosed housing wall.

[0011] According to the invention, this object is achieved by an operator control unit having the features of the embodiment and by a measuring instrument for process or automation engineering having the features of the embodiment, which measuring instrument includes such an operator control unit. Advantageous embodiments of the invention are indicated in the examples.

[0012] The measuring instrument is operated by pressing a control panel in the form of a shape-variable or elastic housing area of the operator control unit. Capacitive sensor elements are respectively arranged below the housing areas. Each sensor element includes a first electrode as the lower capacitor plate and a counter electrode arranged parallel thereto as the upper capacitor plate. Pressing a housing area causes the corresponding upper capacitor plate to approach the corresponding lower capacitor plate, thereby triggering a change in capacitance.

[0013] The first electrode is deposited on a first carrier material, and the counter electrode is deposited on a second carrier material. According to an advantageous further refinement, the elastic housing areas each include local weakening portions in the area of the upper capacitor plate, which are each formed as tactilely perceptible depressions of the outer housing wall.

[0014] Important for the present invention is that the housing regions (and thus the overall housing of the measuring instrument) are arranged adjacent to one another without interruption, and that the sensor element is part of a multilayer printed circuit board complex that abuts against the inner side of the housing regions. Preferably, the housing regions are formed of metal, but other suitable materials (such as plastics) can also be considered. Thus, the housing of the measuring instrument can advantageously be designed as a deep-drawn part, which significantly reduces the manufacturing costs, and the printed circuit board complex is bonded (e.g., firmly bonded, preferably by means of an adhesive) to the inner side of the housing regions, or alternatively is pressed against the inner side of the housing regions (i.e., over the entire control panel) by means of clamping devices. This ensures a permanent and firm connection between the housing regions and the printed circuit board complex.

[0015] The printed circuit board complex at least comprises: a first carrier material, which consists of several segments of rigid printed circuit boards, with flexible intermediate pieces arranged between these segments, and the first carrier material is preferably designed as a rigid-flex printed circuit board; and a second carrier material in the form of a conductive layer, the conductive layer being preferably designed as a conductive film, and both the first carrier material and the second carrier material are separated from one another by an inserted plastic layer. The plastic layer includes several interruptions to form separation regions between the sensor elements and the operator control units. In the context of the present invention, a conductive film is understood to be a polyimide substrate with structured conductive traces, and a rigid-flex printed circuit board is a complex of several segments of conventional rigid printed circuit boards, with each segment of the printed circuit board connected to one another by means of a film-like and thus flexible intermediate piece.

[0016] The manufacture of the printed circuit board complex and its installation in the measuring instrument are both relatively simple, such that the present invention (especially in combination with a measuring instrument housing produced by a deep-drawing process) provides a cost-effective solution for the operator control unit of a measuring instrument with an uninterrupted housing. Deformations that frequently occur due to the deep-drawing process are compensated for by the flexible printed circuit board complex, where the printed circuit board complex is given the necessary stability by a certain proportion of rigid PCB segments that act as a kind of foundation. In particular, when the measuring instrument in question is to be used in the sanitary field, the provision of an operator control unit at the measuring instrument often poses special challenges. The present invention now makes it possible to equip a measuring instrument that must be operable on-site with a hygienically suitable operator control unit at low cost. Description of the Drawings

[0017] The present invention will be explained in more detail below based on exemplary embodiments with reference to the drawings.

[0018] The drawings schematically show:

[0019] Figure 1is a measuring instrument for process measurement engineering according to the prior art;

[0020] Figure 2 is according to the prior art Figure 1 of the housing head of the measuring instrument;

[0021] Figure 3 is a side view of the housing head including an operator control unit according to the present invention, the operator control unit being composed of three control panels;

[0022] Figure 4 is Figure 3 top view of the housing head;

[0023] Figure 5 is a cross-sectional view of the control panel according to the present invention; and

[0024] Figure 6 is a cross-sectional view of the operator control unit composed of two control panels according to the present invention.

[0025] In the following description of the preferred embodiments, the same reference numerals denote the same or equivalent components. Detailed Description of the Invention

[0026] Figure 1 and Figure 2 show a measuring instrument 1 for process measurement engineering according to the prior art, in this case a pressure measuring instrument, which is sold by the applicant under the name PNxxxx. The measuring instrument 1 basically consists of a housing 2, which is divided into an upper part 3 and a lower part 4. The lower part, also called the process connection, on the one hand includes a sensor unit (e.g., a pressure measuring unit in the case of a pressure measuring instrument), and on the other hand enables the measuring instrument 1 to be mechanically connected to a container or pipe containing the medium. Alternatively, in the lower part 4, an interface for connecting a remotely located sensor unit can also be provided. An electronic unit is arranged in the upper part 3, which is used to evaluate and adjust the measurement signals supplied by the sensor unit, and these measurement signals can then be tapped via the shown plug connectors and forwarded, for example, to a PLC.

[0027] On the upper part 3, a housing head 5 is mounted, which according to the present invention includes, among other things, a display device 6 and three operating elements 10. The separated housing head 5 is shown Figure 2 again clearly shows the arrangement of the display 6 and the three operating elements 10. The operating elements 10 are used to operate the measuring instrument 1, i.e., to parameterize or set basic key data (e.g., switch points). Each action is indicated to the user via the display 6.

[0028] Figure 3 and Figure 4The housing head 5 of the operator control unit 10 according to the invention is shown respectively, in which a known operating concept with three key-type input options 10a is employed. However, compared with Figure 1 and Figure 2 known measuring instruments, there are no separate keys here, but rather the housing area 2a is designed to continuously surround the operator control unit 10 without interruption and is only designed as a haptically perceptible depression introduced into the housing area 2a. The surface of the housing area 2a may include corresponding markings that enable the user to correspondingly specify the housing area 2a to be actuated. The dashed circles are intended to indicate these control panels 10a. Thus, the measuring instrument 1 can be operated through the closed housing wall.

[0029] Figure 5 A cross-sectional view of a control panel 10a according to the invention that is part of the operator control unit 10 composed of a number of control panels 10a is shown. Basically, the control panel 10a is composed of a printed circuit board complex 100 that abuts against the inner side of the housing area 2a of the measuring instrument housing 2. In the case of the present invention, the printed circuit board complex 100 is firmly bonded to the inner side of the housing area 2a by means of an adhesive layer 14. However, other fastening or connection options are also conceivable, in particular pressing the printed circuit board complex 100 against the inner side of the housing area 2a by means of a clamping device in the form of a spring element, for example.

[0030] The printed circuit board complex 100 is basically composed of a first carrier material 12 and a second carrier material 13 in the form of a conductive layer. The first carrier material is preferably designed in the form of a rigid-flex printed circuit board, and the conductive layer is preferably formed as a conductive film. The two carrier materials 12, 13 are separated from each other by a segmented plastic layer 15 serving as a spacer in such a way that a measuring chamber 17 is formed between them.

[0031] In the area of the control panel 10a, the rigid-flex printed circuit board 12 includes a flexible intermediate piece 12b. On the lower side of the intermediate piece, the actual conductive traces 12c are arranged, and on the upper side of the intermediate piece, circuit board segments 12a are arranged. Here, the conductive traces 12c also extend transversely through the flexible intermediate piece 12b and the circuit board segments 12a, and form a layered first electrode 11a on the upper side of the circuit board segments 12a in the area of the measuring chamber 17.

[0032] The opposite side of the measuring chamber 17 is formed by the conductive film 13. In this case, the polyimide carrier substrate faces the housing walls 10, 10a, while the copper layer forming the conductive traces faces the measuring chamber 17. This copper layer formed in a layered shape represents a counter electrode 11b in the area of the measuring chamber 17.

[0033] This structure on the one hand gives the printed circuit board composite 100 a certain flexibility, which enables the printed circuit board composite to conform to the interior of the housing and compensate for minor inhomogeneities, especially those caused by manufacturing. And on the other hand, due to the rigid printed circuit board segments 12a in this proportion, the printed circuit board composite is given the necessary stability, and these rigid printed circuit board segments almost act as a kind of foundation.

[0034] The first electrode 11a and the counter electrode 11b together form a capacitive sensor element 11 in the form of a measuring capacitor. The sensor element 11 is arranged below the deformable or elastic housing region 2a, and this housing region is deformed or deflected by the pressure of the applied finger. Due to the firm contact between the printed circuit board composite 100 and the interior of the housing, when the housing region 2a is deformed, the counter electrode 11b deforms in parallel together. The deformation of the counter electrode 11b causes it to move closer to the first electrode 11a arranged parallel to it, which results in a change in the capacitance of the formed capacitor.

[0035] The polyimide carrier of the conductive film 13 additionally serves as an electrical insulator because the housing region 2a itself or its material has no influence on the sensor element 11. First of all, the housing region 2a itself does not represent an electrode, so the housing can be made of any material.

[0036] For better tactile perception and to produce a predetermined bending point, the housing region 2a includes a local weakening portion 2b in the form of a groove-like depression above the sensor element 11.

[0037] This figure is not to scale and is only intended to illustrate the basic structure. The thickness of the housing 10, 10a in the depression area is about 1 mm. Of course, the overall material thickness of the housing 10 can also be greater. The conductive film 13 has a thickness in the range of about 90 μm, while the plastic layer 15 is about 50 μm thick (plus a possible adhesive layer), and the rigid-flex printed circuit board 12 has a total thickness of about 1.6 mm. The width of the measuring chamber 17 is about 13 mm.

[0038] Figure 6 A cross-sectional view of an operator control unit 10 according to the present invention, which consists of two control panels 10a as shown, is shown. To avoid repetition, only additional elements will be discussed here. Figure 5 As can be seen, the housing regions 2a of the two control panels 10a are arranged adjacent to each other without interruption, so that the measuring instrument can be formed by a continuous housing at least in the region of the operator control unit. It can also be seen that the plastic layer 15 includes several interruptions, not only for forming the measuring chamber 17 (as already referred to

[0039] Figure 5 Figure 5described), and is used to form a separation region 16 between two control panels 10a, by means of which the two control panels 10a are mechanically separated from each other, and the pressing of the control panel 10a is not transmitted to the other. The PCB assembly 100 can thus be formed as a unitary body and extend across all control panels 10a.

[0040] The width of the operator control panel 10a is preferably about 20 mm, while the separation region is about 5 mm wide. Figure 6 The operator control unit 10 shown thus has a total width of about 45 mm.

[0041] List of reference numerals

[0042] 1 Measuring instrument

[0043] 2 Housing of the measuring instrument

[0044] 2a Housing area

[0045] 2b Local weakening of the housing area

[0046] 3 Upper part

[0047] 4 Lower part

[0048] 5 Housing head

[0049] 6 Display

[0050] 10 Operator control unit

[0051] 10a Operating button / control panel

[0052] 11 Capacitive sensor element

[0053] 11a First electrode

[0054] 11b Counter electrode

[0055] 12 First carrier material, rigid-flex printed circuit board

[0056] 12a Printed circuit board segment

[0057] 12b Flexible intermediate

[0058] 12c Conductive trace

[0059] 13 Second carrier material, flexible conductive film

[0060] 14 Adhesive layer

[0061] 15 Spacer, plastic layer

[0062] 16 Separation region

[0063] 17 Measuring chamber

[0064] 100 Printed circuit board complex

Claims

1. An operator control unit for a measuring instrument in process or automation engineering, which is composed of at least two operating panels (10a) arranged adjacent to each other, wherein, the operating panels (10a) are operated by respectively pressing shape-changing or elastic housing regions (2a), and each housing region (2a) includes a capacitive sensor element (11) provided thereunder, wherein each of the sensor elements (11) includes a first electrode (11a) as a lower capacitor plate and a counter electrode (11b) arranged parallel above the first electrode (11a) as an upper capacitor plate, and wherein by pressing one of the housing regions (2a), the corresponding upper capacitor plate (11b) approaches the corresponding lower capacitor plate (11a), and thus a capacitance change occurs, wherein the first electrode (11a) is applied to a first carrier material (12), and the counter electrode (11b) is applied to a second carrier material (13), characterized in that, the housing regions (2a) are arranged adjacent to each other without interruption, and the sensor elements (11) are part of a multilayer printed circuit board composite (100) that abuts against the inner side of the housing regions (2a), wherein the printed circuit board composite (100) at least includes: the first carrier material (12), the first carrier material (12) is composed of several segments of rigid printed circuit boards, and flexible intermediates are respectively arranged between the segments; and the second carrier material (13) in the form of a conductive layer, the first carrier material (12) and the second carrier material (13) are separated from each other by an intermediate plastic layer (15), while forming a measuring chamber (17), and wherein the plastic layer (15) includes a plurality of interruptions for forming the sensor elements (11) and a separation region (16) between the operating panels (10a).

2. The operator control unit according to claim 1, characterized in that, each of the elastic housing regions (2a) has a local weakening portion (2b) in the region of the upper capacitor plate (11b), and the local weakening portions (2b) are respectively formed as tactilely perceptible depressions in the outer housing wall.

3. The operator control unit according to any one of claims 1 to 2, characterized in that, the printed circuit board composite (100) is firmly bonded to the inner side of the housing regions (2a).

4. The operator control unit according to any one of claims 1 to 2, characterized in that, the printed circuit board composite is pressed against the inner side of the housing regions (2a) by means of a clamping device.

5. The operator control unit according to any one of claims 1 to 2, characterized in that, the conductive layer of the second carrier material (13) is formed as a conductive film.

6. The operator control unit according to any one of claims 1 to 2, characterized in that, the first carrier material (12) has the form of a rigid-flex printed circuit board.

7. The operator control unit according to any one of claims 1 to 2, characterized in that, the housing area (2a) is formed of metal.

8. A measuring instrument for process or automation engineering, comprising: a multi-part housing (2), wherein a sensor unit or an interface for connecting a sensor unit is arranged in a lower part (4) of the housing, and an upper part (3) of the housing is provided for accommodating an electronic unit for evaluating measurement signals supplied by the sensor unit; and a housing head (5) mounted on the upper part (3) of the housing (2) and including a display device (6) and an operator control unit (10) for operating the measuring instrument (1), wherein the operator control unit (10) is configured according to any one of claims 1-7.

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