Operator Control Unit For a Measuring Instrument For Process or Automation Engineering, and Measuring Instrument Having an Operator Control Unit of This Kind

Abstract

The invention relates to an operator control unit for a measuring instrument for process or automation engineering, the operator control unit consisting of at least two adjacently arranged control panels (10a), the control panels (10a) being operated by pressing on a respective shape-variable or elastic housing region (2a) having a respective capacitive sensor element (11) disposed thereunder. The sensor elements (11) each have a first electrode (11a) as a lower plate capacitor and a counter-electrode (11b) arranged in parallel thereabove as an upper plate capacitor, and pressing on one of the housing regions (2a) causes the respective upper plate capacitor (11b) to approach the respective 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 adjacently to one another in an uninterrupted manner, and the sensor elements (11) are parts of a multi-layered composite printed circuit board (100), which bears against the inner sides of the housing regions (2a), wherein the composite printed circuit board (100) comprises at least the first carrier material (12), which consists of a plurality of segments of rigid circuit boards each with flexible intermediate pieces arranged therebetween, and the second carrier material (13) in the form of a conductive layer, which two carrier materials are spaced apart from one another via an interposed plastic layer (15), forming a measuring chamber (17), and wherein the plastic layer (15) has a plurality of interruptions for forming the sensor elements (11) and a decoupling region (16) between the control panels (10a).

Claims

1. Operator control unit for a measuring instrument of process or automation engineering, consisting of at least two operating panels (10a) arranged next to each other, wherein the operating panels (10a) are operated by respectively pressing on a shape-changing or elastic housing region (2a) each comprising a capacitive sensor element (11) disposed underneath, wherein the sensor elements (11) each comprise a first electrode (11a) as a lower capacitor plate and a counter electrode (11b) arranged in parallel thereabove as an upper capacitor plate and wherein by pressing one of the housing regions (2a) an approach of the respective upper capacitor plate (11b) to the respective lower capacitor plate (11a) and thus a change in capacitance occurs, wherein the first electrode (11a) is applied onto a first carrier material (2) and the counter electrode (11b) is applied onto a second carrier material (13), characterized in that the housing regions (2a) are arranged next to one another without interruption, and in that the sensor elements (11) are parts of a multilayer printed circuit board composite (100) which abuts the inner sides of the housing regions (2a), wherein the printed circuit board composite (100) comprises at least the first carrier material (12), which consists of several segments of rigid printed circuit boards with flexible intermediate pieces respectively arranged therebetween, and the second carrier material (13) in the form of a conductive layer, both of which are separated from one another by an intermediate plastic layer (15) while forming a measuring chamber (17), and wherein the plastic layer (15) comprises a plurality of interruptions for forming the sensor elements (11) and a decoupling area (16) between the control panels (10a).

2. Operator control unit according to claim 1, characterized in that the elastic housing regions (2a) each have a partial weakening (2b) in the area of the upper capacitor plate (11b), which are respectively formed as a haptically perceptible depression in the outer housing wall.

3. 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 sides of the housing regions (2a).

4. 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 sides of the housing regions (2a) by means of a clamping device.

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

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

7. Operator control unit according to any one of the preceding claims, characterized in that the housing regions (2a) are formed from a metal.

8. Measuring instrument of process or automation engineering, comprising a multi-part housing (2), wherein in the lower part (4) of the housing a sensor unit or an interface for connecting a sensor unit is arranged and the upper part (3) of the housing is provided for accommodating an electronic unit for evaluating the measurement signals supplied by the sensor unit, and a housing head (5) mounted on the upper part (3) of the housing (2) and comprising 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 the preceding claims.

Description

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

[0018] The drawing schematically show:

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

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

[0021] FIG. 3 a side view of a housing head comprising an operator control unit according to the invention consisting of three control panels;

[0022] FIG. 4 a top view of the housing head from FIG. 3;

[0023] FIG. 5 a sectional view through a control panel according to the invention; and

[0024] FIG. 6 a sectional view through an operator control unit according to the invention consisting of two control panels.

[0025] In the following description of the preferred embodiments, identical reference symbols denote identical or comparable components.

[0026] FIGS. 1 and 2 show a measuring instrument 1 for process measurement engineering in accordance with the prior art, in this case a pressure measuring instrument, which is sold by the applicant under the designation PNxxxx. The measuring instrument 1 essentially consists of a housing 2, which is divided into an upper part 3 and a lower part 4. The lower part, also referred to as process connection, comprises on the one hand the sensor unit, for example a pressure measuring cell in the case of a pressure measuring instrument, and on the other hand enables the mechanical connection of the measuring instrument 1 to the container or pipe containing the medium. Alternatively, in the lower part 4 there can also be provided an interface for connecting a remotely located sensor unit. In the upper part 3 the electronic unit is disposed, which is used for the evaluation and conditioning of the measurement signals supplied by the sensor unit, which can then be tapped via the plug connection shown and forwarded, for example, to a PLC.

[0027] A housing head 5, comprising among others a display device 6 and three operating elements 10 according to the invention, is mounted on the upper part 3. FIG. 2, which shows the separated housing head 5, once 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 carry out a parameterization or a setting of essential key data, such as, for example, the switching points. The respective actions are indicated to the user via the display 6.

[0028] FIGS. 3 and 4 respectively show a housing head 5 comprising an operator control unit 10 according to the invention, wherein the known operating concept with three key-type input options 10a has been adopted. In contrast to the known measuring instrument of FIGS. 1 and 2, however, no separate keys are present here, but the housing region 2a is designed around the operator control unit 10 without interruption and merely designed as a haptically perceptible depression introduced into the housing region 2a. The surface of the housing region 2a can comprise corresponding markings that enable the user to assign the housing region 2a to be actuated accordingly. The dashed circles are intended to indicate these control panels 10a. As a result, it is possible to operate the measuring instrument 1 through the closed housing wall.

[0029] FIG. 5 shows a sectional view through a control panel 10a according to the invention as a part of an operator control unit 10 consisting of several control panels 10a. Basically, the control panel 10a consists of a printed circuit board, composite 100, which abuts the inside of a housing region 2a of a measuring instrument housing 2. In the present case, the printed circuit board composite 100 is firmly bonded to the inside 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 composite 100 against the inside of the housing region 2a by means of a clamping device, e.g. in the form of spring elements.

[0030] The printed circuit board composite 100 essentially consists of a first carrier material 12, which is preferably designed in the form of a flex-rigid printed circuit board, and a second carrier material 13 in the form of a conductive layer, which is preferably formed as a conductor film. Both carrier materials 12, 13 are spaced apart from each other by a segment-like plastic layer 15 as a spacer in such a way that a measuring chamber 17 is formed between them.

[0031] In the area of a control panel 10a, the flex-rigid printed circuit board 12 comprises a flexible intermediate piece 12b, on the underside of which the actual conductor track 12c is arranged and on the upper side of which a printed circuit board segment 12a is arranged. Here, the conductor track 12c also extends transversely through the flexible intermediate piece 12b and the printed circuit board segment 12a and forms at the upper side of the printed circuit board segment 12a in the area of the measuring chamber 17 a laminar, first electrode 11a.

[0032] The opposite side of the measuring chamber 17 is formed by the conductor film 13. In this case, the polyimide carrier substrate faces the housing wall 10, 10a, while a copper layer forming the conductor track faces the measuring chamber 17. This copper layer, which is formed with a laminar shape, represents a counter-electrode 11b in the area of the measuring chamber 17.

[0033] This structure gives the printed circuit board composite 100, on the one hand, a certain flexibility which enables it to conform to the inside of the housing and to compensate for minor unevenness, in particular due to manufacturing, and, on the other hand, the necessary stability due to the proportion of rigid printed circuit board segments 12a which quasi 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. This sensor element 11 is arranged below a deformable or elastic housing region 2a, which is deformed or deflected by the pressure of an applied finger. As a result of the firm contact of the printed circuit board composite 100 with the inside of the housing, the counter-electrode 11b is co-deformed in parallel when the housing region 2a is deformed. The deformation of the counter electrode 11b causes it to move closer to the first electrode 11a arranged parallel thereto, which leads to a change in capacitance of the formed capacitor.

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

[0036] For a better haptic perception and in order to create a predetermined bend point, the housing region 2a comprises a partial weakening 2b in the form of a trough-like depression above the sensor element 11.

[0037] The illustration is not to scale and is only intended to clarify the basic structure. The thickness of the housing 10, 10a is about 1 mm in the area of the depression. The overall material thickness of the housing 10 can, of course, also be higher. 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 flex-rigid 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] FIG. 6 shows a sectional view through an operator control unit 10 according to the invention, consisting of two control panels 10a as shown in FIG. 5. To avoid repetition, only the additional elements will be discussed here.

[0039] It can be seen that the housing regions 2a of the two control panels 10a are arranged next to each other without interruption, so that the measuring instrument—at least in the area of the operator control unit—can be formed from a continuous housing. It can further be seen that the plastic layer 15 comprises several interruptions, not only for forming the measuring chamber 17, as already described with respect to FIG. 5, but also for forming a decoupling area 16 between the two control panels 10a, by means of which the two control panels 10a are mechanically separated from each other and a pressing of a control panel 10a is not transferred to the other. The PCB composite 100 can thus be formed as a single piece and extends across all of the control panels 10a.

[0040] The width of an operator control panel 10a is preferably about 20 mm, while the decoupling area is about 5 mm wide. The operator control unit 10 shown in FIG. 6 thus has an overall width of about 45 mm.

LIST OF REFERENCE SYMBOLS

[0041] 1 measuring instrument

[0042] 2 housing of the measuring instrument

[0043] 2a housing region

[0044] 2b partial weakening of the housing region

[0045] 3 upper part

[0046] 4 lower part

[0047] 5 housing head

[0048] 6 display

[0049] 10 operator control unit

[0050] 10a operating button/control panel

[0051] 11 capacitive sensor element

[0052] 11a first electrode

[0053] 11b counter electrode

[0054] 12 first carrier material, flex-rigid printed circuit board

[0055] 12a printed circuit board segment

[0056] 12b flexible intermediate piece

[0057] 12c conductor track

[0058] 13 second carder material, flexible conductor film

[0059] 14 adhesive layer

[0060] 15 spacer, plastic layer

[0061] 16 decoupling area

[0062] 17 measuring chamber

[0063] 100 printed circuit board composite