Test element for automated testing of a touch panel

Abstract

A test element 1 for automated testing of a touch panel (20, fig 10) comprises a pin 10, and a touch element 11 flexibly mounted on the pin. The touch element may be flexibly mounted on the pin with a

Description

The present invention is related to a test element for automated testing of a touch panel. The invention is further directed towards a test system comprising such test element. In modern motor vehicles, an increasing amount of information is provided for the driver or other vehicle occupants, which goes far beyond the display of the vehicle's condition. Conventional combination instruments are therefore increasingly being replaced by freely programmable, digital displays. Nowadays, those displays are often provided with a touch functionality. Such touch panels enable a user to input commands by touching the display screen rather than relying on traditional inputs such as buttons. Before a touch panel is brought to market, it typically undergoes testing to ensure that the touch panel is fully functional and operational upon deployment. To this end, a measurement robot with at least one artificial finger may be used. For example, US 2012 / 0146956 A1 discloses a touch panel test arrangement comprising a robot with a touch element that can simulate a finger. The touch panel can be touched simultaneously with two touch elements that can be adjusted relative to each other. DE 10 2015 102 238 A1 discloses a method for checking a function-triggering surface by applying pressure to the surface, said surface reacting in a haptically-detectable manner following an application of pressure which triggers the function. The surface reaction triggered by this application of pressure is detected by a vibration sensor which is integrated in a sensor element. With the known test systems, measurements need to be performed perpendicular to the surface of the touch panel. In case of curved displays, which are often used in automotive applications, this requires a mathematical model of the display surface to properly position the robot finger. However, the mathematical model does not necessarily represent the reality. Curved displays do typically not have one radius, but up to three. This makes a mathematical approach more difficult. Furthermore, known artificial fingers do sometimes not have sufficient degrees of freedom. Therefore, they cannot match every curved surface. It is an object of the present invention to provide an improved solution for automated testing of a touch panel. This object is achieved by a test element according to claim 1 and by a test system according to claim 11. The dependent claims include advantageous further developments and improvements of the present principles as described below. According to a first aspect, a test element for automated testing of a touch panel comprises a pin and a touch element, wherein the touch element is flexibly mounted on the pin. The pin preferably is a metallic pin. When the touch element gets in contact with the surface of the touch panel, it will automatically align with this surface. This self-aligning ensures that the touch element is always perpendicular to the touch panel, which is particularly advantageous for curved displays with a touch functionality. There is no need to make use of a camera system or other sensors incorporating complex algorithms to ensure perpendicular placement of the test element, as the touch element will automatically align correctly relative to the surface. In an advantageous embodiment, the touch element is flexibly mounted on the pin with a rubber element. Using a rubber element for mounting has the advantage that the solution can be implemented at low cost. For example, the rubber element may be made of an Elastomer, e.g. Caoutchouc. In an advantageous embodiment, the pin has a tip, and the touch element is flexibly mounted on the tip of the pin with a magnetic element. Using a magnetic element for mounting has the advantage that a magnetic element is more durable than a rubber element. Furthermore, a larger tilting range for the touch element can be achieved. For example, the magnetic element may be a Neodymium magnet. In an advantageous embodiment, the magnetic element has a conical or spherical bore configured to accommodate the tip of the pin. The bore ensures a proper alignment of the touch element relative to the pin. Furthermore, when the tip of the metallic pin is inserted into the bore, it will be magnetized. In this way, no further steps are needed for mounting the touch element. In an advantageous embodiment, the pin has a tip, and the touch element is self-aligning on the touch panel. For example, the touch element may have the shape of a disc. In an advantageous embodiment, the pin is mounted movably in an axial direction. The test element will usually be mounted on a robotic arm of a test system. When the pin is mounted movably in an axial direction, the pin will move in the axial direction when the touch element gets in contact with the surface of the touch panel. Therefore, fast movements of the robotic arm are possible without the risk of damaging the touch panel. In an advantageous embodiment, the test element further comprises a linear guiding system for the pin. The linear guiding system provides a robust bearing of the pin. In an advantageous embodiment, the test element further comprises a spring configured to push the pin in the axial direction. The spring ensures that the touch element is reliably pushed against the surface of the touch panel. Furthermore, the spring allows a large movement of a robotic arm of a test system and, therefore, a long time to regulate the touch force. In an advantageous embodiment, the pin is interchangeably fastened to a holder of the test element. Alternatively or in addition, the touch element may be interchangeably fastened to the pin. Both solutions are particularly useful if tests with touch elements of different sizes are to be performed. Advantageously, a test system for automated testing of a touch panel comprises a robotic arm and a test element according to the invention. Such a system is well suited for testing whether a touch panel is fully functional and operational upon deployment. In an advantageous embodiment, the test system is configured to coarsely align the test element in relation to a surface of the touch panel using the robotic arm. In this way, only small tilting movements occur when the touch element gets in contact with the surface of the touch panel. Further features of the present invention will become apparent from the following description and the appended claims in conjunction with the figures. Figures Fig. 1 shows a first embodiment of a test element according to the invention for automated testing of a touch panel; Fig. 2 shows a holder of the test element of Fig. 1; Fig. 3 shows a second embodiment of a test element according to the invention for automated testing of a touch panel; Fig. 4 shows an exploded view of the test element of Fig. 3; Fig. 5 shows a cut through the test element of Fig. 3; Fig. 6 shows a first embodiment of a touch element mounted on a pin of a test element; Fig. 7 shows a cut through the touch element and the pin of Fig. 6; Fig. 8 shows a second embodiment of a touch element mounted on a pin of a test element; Fig. 9 shows a cut through the touch element and the pin of Fig. 8; and Fig. 10 shows a test system for automated testing of a touch panel. Detailed description The present description illustrates the principles of the present disclosure. It will thus be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described or shown herein, embody the principles of the disclosure. All examples and conditional language recited herein are intended for educational purposes to aid the reader in understanding the principles of the disclosure and the concepts contributed by the inventor to furthering the art and are to be construed as being without limitation to such specifically recited examples and conditions. Moreover, all statements herein reciting principles, aspects, and embodiments of the disclosure, as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof. Additionally, it is intended that such equivalents include both currently known equivalents as well as equivalents developed in the future, i.e., any elements developed that perform the same function, regardless of structure. Thus, for example, it will be appreciated by those skilled in the art that the diagrams presented herein represent conceptual views of illustrative components embodying the principles of the disclosure. Fig. 1 shows a first embodiment of a test element 1 according to the invention for automated testing of a touch panel. The test element 1 comprises a pin 10, which is interchangeably fastened to a holder 16, e.g., using a screw joint. A touch element 11 is flexibly mounted on the pin 10. In this embodiment, the holder 16 is a rod. A more detailed view of the holder 16 is shown in Fig. 2. The pin 10 is mounted movably in an axial direction Z. To this end, the test element 1 comprises a linear guiding system 14 for the pin 10. The linear guiding system 14 comprises a first bearing bush 140 and a second bearing bush 141, which are configured to guide the holder 16. The two bearing bushes 140, 141 are arranged in a cylindrical housing 19, which is closed at its ends by respective closure plates 191, 192. The closure plates 191, 192 are fastened to the housing 19 by several screws 193. On the inside, the housing 19 preferably has guide channels for accommodating corresponding protrusions 160 of the holder. At its upper end, the housing 19 may have a mounting plate for mounting the test element 1 on a robotic arm of a test system. The test element 1 comprises a spring 15 configured to push the pin 10 in the axial direction Z. The spring 15 is arranged around the holder 16 and pushes against a spring support 150, which is secured on the holder 16 by a circlip 151. A further circlip 161 secures the holder 16 in the linear guiding system 14. Fig. 3 shows a second embodiment of a test element 1 according to the invention. Fig. 4 and Fig. 5 show an exploded view of this test element 1 and a cut through this test element 1, respectively. The test element 1 comprises the pin 10, which is interchangeably fastened to the holder 16 using a screw joint 18. The touch element 11 is flexibly mounted on the pin 10. The pin 10 is mounted movably in an axial direction Z. To this end, the test element 1 comprises a linear guiding system 14 for the pin 10. The linear guiding system 14 comprises a linear stage 142, which is mounted on a base plate 143 using screws 144. The holder 16 is mounted on this linear stage 142 using screws 144 as well. At its end, a mounting plate 17 is fastened to the base plate 143 for mounting the test element 1 on a robotic arm of a test system. A rod 145 extends from the mounting plate 17 into a bore 162 of the holder 16. A spring 15, which is arranged around the rod 145 and pushes against the holder 16, is configured to push the pin 10 in the axial direction Z. Fig. 6 shows a first embodiment of a touch element 11 mounted on a pin 10 of a test element. Fig. 7 shows a cut through the touch element 11 and the pin 10. The touch element 11 has the shape of a disc with a diameter between 3 mm and 30 mm. In this embodiment, the touch element 11 is mounted on the pin 10 with a rubber element 12. The rubber element 12 has a bore 120, into which a connecting section 101 of the pin 10 is inserted. The rubber element 12 is flexible, which allows the touch element 11 to tilt relative to the Z axis when it gets in contact with the surface of a touch panel. In this way, the touch element 11 will automatically align with this surface. Fig. 8 shows a second embodiment of a touch element 11 mounted on a pin 10 of a test element. Fig. 9 shows a cut through the touch element 11 and the pin 10. The touch element 11 has the shape of a disc with a diameter between 3 mm and 30 mm. In this embodiment, the touch element 11 is mounted on the pin 10 with a magnetic element 13. The magnetic element 13 has a conical or spherical bore 130, into which a tip 100 of the pin 10 is inserted. If the pin 10 is made of a metal that can be magnetized, such as iron, the tip 100 will be magnetized when it is inserted into the bore 130. Due to the shape of the bore 130, the touch element 11 can tilt relative to the Z axis when it gets in contact with the surface of a touch panel. In this way, the touch element 11 will automatically align with this surface. Fig. 10 shows a test system 30 for automated testing of a touch panel 20. The test system 30 comprises a robotic arm 31, on which a test element 1 according to the invention is mounted. With the robotic arm 31, the test element 1 can be moved to different positions relative to the touch panel 20 for performing the desired tests. Preferably, the test system 30 is configured to coarsely align the test element 1 in relation to a surface of the touch panel 20 using the robotic arm 31. This is particularly advantageous for curved displays with a touch functionality, as in this way, only small tilting movements occur when the touch element of the test element 5 10 gets in contact with the surface of the touch panel 20. Reference numerals 1 Test element 10 Pin 100 Tip 101 Connecting section 11 Touch element 12 Rubber element 120 Bore 13 Magnetic element 130 Bore 14 Linear guiding system 140 Bearing bush 141 Bearing bush 142 Linear stage 143 Base plate 144 Screw 145 Rod 15 Spring 150 Spring support 151 Circlip 16 Holder 160 Protrusion 161 Circlip 162 Bore 17 Mounting plate 170 Screw 18 Screw joint 19 Housing 191 Closure plate 192 Closure plate 193 Screw 20 Touch panel 30 Test system 31 Robotic arm

Claims

1. A test element (1) for automated testing of a touch panel (20), comprising:- a pin (10); and- a touch element (11);wherein the touch element (11) is flexibly mounted on the pin (10).

2. The test element (1) according to claim 1, wherein the touch element (11) is flexibly mounted on the pin (10) with a rubber element (12).

3. The test element (1) according to claim 1, wherein the pin (10) has a tip (100), and the touch element (11) is flexibly mounted on the tip (100) of the pin (10) with a magnetic element (13).

4. The test element (1) according to claim 3, wherein the magnetic element (13) has a conical or spherical bore (130) configured to accommodate the tip (100) of the pin (10).

5. The test element (1) according to claim 1, wherein the pin (10) has a tip (100), and the touch element (11) is self-aligning on the touch panel (20).

6. The test element (1) according to one of the preceding claims, wherein the pin (10) is mounted movably in an axial direction (Z).

7. The test element (1) of claim 5, further comprising a linear guiding system (14) for the pin (10).

8. The test element (1) of claim 6 or 7, further comprising a spring (15) configured to push the pin (10) in the axial direction (Z).

9. The test element (1) according to one of the preceding claims, wherein the pin (10) is interchangeably fastened to a holder (16) of the test element (1).

10. The test element (1) according to one of the preceding claims, wherein the touch element (11) is interchangeably fastened to the pin (10).

11. A test system (30) for automated testing of a touch panel (20), comprising: - a robotic arm (31); and- a test element (1) according to one of the preceding claims.

12. The test system (30) according to claim 11, wherein the test system (30) is configured to coarsely align the test element (1) in relation to a surface of the touch 5 panel (20) using the robotic arm (31).

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