SENSOR DEVICE

Abstract

A sensor device comprising at least a first substrate, a capacitive sensor for recording the approach of an object, a piezoelectric sensor for recording a pressure, wherein the capacitive sensor is arranged on a first side of the first substrate and the piezoelectric sensor is arranged on a second side of the first substrate, wherein the second side is opposite the first side, or wherein the capacitive sensor and the piezoelectric sensor are arranged on the same side of the substrate.

Claims

1. Sensor device (1), comprising: a first substrate (3); a capacitive sensor (4) for detecting an approach of an object, wherein at least a portion of the capacitive sensor (4) is arranged on a first side of the first substrate (3); and a piezoelectric sensor (5) for detecting a pressure or a pressure change, wherein the piezoelectric sensor (5) is arranged in the sensor device (1) spaced from a second side of the first substrate (3), the second side of the first substrate (3) being opposite to the first side thereof.

2. Sensor device (1) as claimed in claim 1, further comprising: a second substrate (10); wherein the capacitive sensor (4) is arranged on the first substrate (3); and wherein the piezoelectric sensor (5) is arranged on the second substrate (10); and wherein the second substrate (10) is laminated onto the first substrate (3).

3. Sensor device (1) as claimed in claim 1, wherein a base surface of the capacitive sensor (4) substantially matches a base surface of the piezoelectric sensor (5).

4. Sensor device (1) as claimed in claim 1, further comprising a shield (7) between the capacitive sensor (4) and the piezoelectric sensor (5).

5. Sensor device (1) as claimed in claim 4, wherein the shield (7) is arranged on a second side of the first substrate (3).

6. Sensor device (1) as claimed in claim 1, wherein the capacitive sensor (4) comprises: an electrode layer (4a); a bottom electrode (4b); wherein the electrode layer (4a) and the bottom electrode (4b) are insulated from one another by the first substrate (3).

7. Sensor device (1) as claimed in claim 1, wherein the piezoelectric sensor (5) further comprises: a bottom electrode layer (5a); a ferroelectric copolymer layer (5b); and a top electrode layer (5c), wherein the ferroelectric copolymer layer (5b) is located between the top and bottom electrode layers (5a, 5c).

8. Sensor device (1) as claimed in claim 1, further comprising a lacquer layer (9) for protecting a surface of the sensor device (6).

9. Sensor device (1) as claimed in claim 4, further comprising: a second dielectric insulation layer (8) between the shield (7) and the piezoelectric sensor (5).

10. A system comprising: at least one sensor device (1) as claimed in claim 1; a device for approach recognition (17) for detecting a first signal (16) from the capacitive sensor (4), wherein the first signal (16) is an approach signal; and a device for contact recognition (19) for detecting a second signal (18) from the piezoelectric sensor (5), wherein the second signal (18) is a contact signal.

11. Manipulator device, comprising at least one manipulator finger (14), wherein each individual manipulator finger (14) comprises at least one sensor device (1) as claimed in claim 1 for detecting a holding force in a tactile manner during a gripping procedure of the manipulator device.

12. (canceled)

13. Sensor device (1) as claimed in claim 6, wherein the electrode layer (4a) is arranged on the first side of the first substrate (3) and the bottom electrode (4b) is arranged on the second side of the first substrate (3).

14. Sensor device (1) as claimed in claim 1, wherein the capacitive sensor (4) comprises: an electrode layer (4a); a bottom electrode (4b); and a first dielectric insulation layer (4c), wherein the electrode layer (4a) and the bottom electrode (4b) are insulated from one another by the first dielectric insulation layer (4c).

15. Sensor device (1) as claimed in claim 14, wherein the capacitive sensor (4) is wholly arranged on the first side of the first substrate (3).

16. Sensor device (1) as claimed in claim 1, wherein the capacitive sensor (4) and the piezoelectric sensor (5) form a stack sensor (2).

17. Sensor device (1) as claimed in claim 7, wherein the bottom electrode layer (5a) is formed from PEDOT:PSS.

18. Sensor device (1) as claimed in claim 8, wherein the lacquer layer (9) is formed on the capacitive sensor (4).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Different exemplified embodiments of the invention will be described in greater detail hereinafter. In the drawing:

[0034] FIG. 1 shows a schematic structure of a first exemplified embodiment of the sensor device in accordance with the invention;

[0035] FIG. 2 shows a schematic structure of a second exemplified embodiment of the sensor device in accordance with the invention;

[0036] FIG. 3 shows an exemplified embodiment of a capacitive sensor;

[0037] FIG. 4 shows an exemplified embodiment of a piezoelectric sensor; and

[0038] FIG. 5 shows an exemplified embodiment of a robot finger in accordance with the invention;

[0039] FIG. 6 shows a schematic overview of signals output by the sensor device.

DESCRIPTION OF THE FIGURES

[0040] FIG. 1 shows a schematic structure of a first exemplified embodiment of a sensor device 1 in accordance with the invention. The sensor device 1 is formed by means of a layer stack 2. The layer stack 2 comprises a first substrate 3. A capacitive sensor 4 is arranged on a first side (the upper side in the illustration) of the first substrate 3. The capacitive sensor 4 serves to detect an approach of an object to the sensor 1 in a contactless manner.

[0041] A piezoelectric sensor 5 is arranged on a second side of the first substrate 3 (the lower side in the illustration). The piezoelectric sensor 5 serves to detect a pressure and thus to determine a holding force which the object exerts on the sensor 1 when it is in contact with a surface of the sensor device 6.

[0042] The capacitive sensor 3 is formed by means of an electrode layer 4a and a bottom electrode 4b. Arranged between the electrode layer 4a and the bottom electrode 4b is a first dielectric insulation layer 4c which insulates the electrode layer 4a and the bottom electrode 4b of the capacitive sensor 4 from one another. The electrodes of the electrode layer 4a consist preferably of an ink having a silver proportion.

[0043] The piezoelectric sensor 5 is formed by means of three layers. A first layer 5a of the piezoelectric sensor 5 forms a bottom electrode layer. The bottom electrode layer 5a is formed preferably from PEDOT. It has a thickness of ca. 1 μm. A second layer 5b of the piezoelectric sensor 5 is a ferroelectric copolymer layer which is formed preferably from PVDF:TrFE in a ratio of 70:30 mol. % and has a thickness of ca. 5 μm. A third layer 5c of the piezoelectric sensor 5 is a top electrode which consists preferably of PEDOT and has a thickness of ca. 1 μm. A shield (Shield GND) 7 is arranged on the second side of the first substrate 3. The shield 7 serves to electrically shield the capacitive sensor 4 and the piezoelectric sensor 5 from one another. The shield 7 consists preferably of silver paste and is electrically coupled to earth.

[0044] The sensor device 1 further comprises a second dielectric insulation layer 8. The second insulation layer 8 is arranged between the first substrate 3 and the piezoelectric sensor 5 and serves to insulate the piezoelectric sensor 5 from the first substrate 3. The shield 7 is arranged between the first substrate 3 and the second dielectric insulation layer 8.

[0045] A further insulation layer (protective layer) 9 is arranged on the capacitive sensor 4. It is formed by means of a lacquer and serves to protect the sensor device 1 during the detection of compressive forces resulting from the contact of objects.

[0046] Within the layer stack 2, the capacitive sensor 4 and the piezoelectric sensor 5 are oriented with respect to one another. The base surfaces of the capacitive sensor 4 and the piezoelectric sensor 5 correspond substantially to one another. The entire sensor device 1 forms a flexible foil.

[0047] FIG. 2 shows a schematic structure of a second exemplified embodiment of the sensor device 1 in accordance with the invention. In contrast to FIG. 1, the sensor device 1 has an additional second substrate 10. The second substrate 10 is a PET substrate. The capacitive sensor 4 is arranged on the first substrate 3, i.e. the electrode layer 4a is applied to the first substrate 3. The bottom electrode 4b of the capacitive sensor 4 is arranged on a side of the first substrate 3 opposite the electrode layer 4a. The first substrate 3 insulates the electrode layer 4a from the bottom electrode 4b. In this embodiment, it assumes the function of the first dielectric layer 4c. The piezoelectric sensor 5 is arranged on the second substrate 10, i.e. the layers 5a, 5b, 5c are applied to the second substrate 10. The shield 7 is arranged between the first substrate 3 and the second substrate 10. The first substrate 3 is connected to the second substrate 10 by means of a laminate layer 11, wherein the laminate layer 11 is arranged between the bottom electrode 4b and the shield 7. The laminate layer 11 is an adhesive layer.

[0048] FIG. 3 shows an exemplified embodiment of a capacitive sensor 4. The capacitive sensor is designed as a foil and comprises the first substrate 3, to which the electrode layer 4a is applied. The electrode layer consists of three top electrodes and has a first geometric pattern 12. Located underneath the top electrode is a common bottom electrode 4b (also referred to as an active guard layer). The top electrode and the bottom electrode are insulated from one another by means of the first substrate 3.

[0049] FIG. 4 shows an exemplified embodiment of a piezoelectric sensor 5. The piezoelectric sensor 5 is designed as a foil and comprises the second substrate 10, to which the layers 5a, 5b, 5c are applied. The first layer 5a of the piezoelectric sensor 5 has a second geometric pattern 13. The first layer 5a of the piezoelectric sensor 5 is segmented and forms a 4×2 array. In the sensor device 1, the geometric patterns 12, 13 of the two sensors 4, 5 are oriented in relation to one another.

[0050] FIG. 5 shows an exemplified embodiment of a manipulator finger 14 in accordance with the invention. The manipulator finger 14 has a front side and a rear side, wherein the rear side carries a circuit board 15 which serves to control the sensor 1. The sensor device 1 is arranged on the (non-visible) front side of the manipulator finger 14. The front side of the manipulator finger 14 forms the gripping surface of the manipulator and carries the sensor device 1. The manipulator finger 14 has preferably a planar gripping surface of 62 mm×62 mm. In an operational state, the sensor device 1 is arranged on the manipulator limb 14. The sensor is oriented such that the protective layer 9 forms a sensor surface 6 which faces objects to be detected. The approach of an object to the sensor device 1 is detected in a contactless manner by means of the capacitive sensor 4. If an object is to be handled by means of the manipulator limb 14, the piezoelectric sensor 5 determines the forces, which occur between the manipulator limb 14 and object, after contact between the object and the surface of the sensor device 6 is established. By designing the sensors as flexible sensor stack foils, the forces are transmitted mechanically by the capacitive sensor 4 to the piezoelectric sensor 5 and are measured thereby.

[0051] FIG. 6 shows a schematic overview of signals output by the sensor device 1 or the fragmentation of an output signal into different signal components. The layer stack 2 which forms the sensor device 1 generates a signal which comprises two signal components. The capacitive sensor 4 generates a first signal component 16 which is interpreted and output as an approach signal by means of a device for approach recognition 17. The device for approach recognition 17 is connected to the sensor stack 2 by means of an electrical connection. The piezoelectric sensor 5 generates a second signal component 18 which is interpreted as a contact signal by means of a device for contact recognition 19. The device for contact recognition 19 is connected to the sensor stack 2 by means of an electrical connection. An approach signal can be a three-dimensional reconstruction of the surrounding space (x, y, z). However, an approach signal can also be interpreted as a sectional image, i.e. as a two-dimensional reconstruction (x, z or y, z) of the surrounding space. Pure distance information (z) can also be output. A limit value for the distance can be established. Below the limit value, a detection signal can be output, or an output of the approach signal can be restricted to cases in which the value is less than the distance limit value. This ensures that undesired detections are reduced.