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EP-4738707-A1 - KNOB AND RELATED SENSING CIRCUIT

EP4738707A1EP 4738707 A1EP4738707 A1EP 4738707A1EP-4738707-A1

Abstract

A knob is disposed on a touch panel including a first touch sensor, a second touch sensor and a third touch sensor. The knob includes a bottom surface and a first connector. The bottom surface includes a sensing electrode aligned with the first touch sensor, a first common electrode aligned with the second touch sensor and receiving a first reference voltage from the second touch sensor, and a second common electrode aligned with the third touch sensor and receiving a second reference voltage from the third touch sensor. The first connector controls the sensing electrode to be conducted with the first common electrode and the second common electrode or not when the knob rotates. A touch sensing circuit of the touch panel determines a rotation direction of the knob according to a signal variation of the first touch sensor.

Inventors

  • TSAI, WU-CHUAN

Assignees

  • Novatek Microelectronics Corp.

Dates

Publication Date
20260506
Application Date
20250408

Claims (18)

  1. A knob (30) disposed on a touch panel (300), the touch panel (300) comprising a first touch sensor (S1), a second touch sensor (S2) and a third touch sensor (S3), characterized by the knob (30) comprising: a bottom surface, comprising: a sensing electrode (RX), aligned with the first touch sensor (S1); a first common electrode (COM1), aligned with the second touch sensor (S2) and receiving a first reference voltage from the second touch sensor (S2); and a second common electrode (COM2), aligned with the third touch sensor (S3) and receiving a second reference voltage from the third touch sensor (S3); and a first connector (406, 408) to control the sensing electrode (RX) to be conducted with the first common electrode (COM1) and the second common electrode (COM2) or not when the knob (30) rotates; wherein a touch sensing circuit (1100) of the touch panel (300) determines a rotation direction of the knob (30) according to a signal variation of the first touch sensor (S1).
  2. The knob (30) of claim 1, characterized in that the first common electrode (COM1) or the second common electrode (COM2) further receives a third reference voltage from a touch object operating the knob (30), to form the signal variation of the first touch sensor (S1).
  3. The knob (30) of claim 2, characterized by further comprising: a conductor, coupled to the first common electrode (COM1) or the second common electrode (COM2), to receive the third reference voltage from the touch object when the touch object operates the knob (30).
  4. The knob (30) of claims 1-3, characterized in that the first common electrode (COM1) and the second common electrode (COM2) have different sizes.
  5. The knob (70) of claims 1-4, characterized in that the bottom surface further comprises a third common electrode (COM3), which is electrically connected to the sensing electrode (RX) when the knob (70) is pressed and not electrically connected to the sensing electrode (RX) when the knob (70) is not pressed.
  6. The knob (70) of claim 5, characterized by comprising: a second connector (806) to control the sensing electrode (RX) to be conducted with the third common electrode (COM3) or not when the knob (70) is pressed.
  7. The knob (30, 70) of claims 1-6, characterized in that the knob (30, 70) comprises the only one sensing electrode (RX).
  8. The knob (30, 70) of claims 1-7, characterized in that at least one of the first reference voltage and the second reference voltage is a ground voltage.
  9. The knob (30, 70) of claims 1-8, characterized in that the first common electrode (COM1) is coupled to a common electrode ring (412), and the sensing electrode (RX) is coupled to a sensing electrode ring (402), wherein a connecting post (406) is disposed on the sensing electrode ring (402) and electrically connected to the sensing electrode ring (402).
  10. The knob (30, 70) of claim 9, characterized in that the common electrode ring (412) contacts the connecting post (406) and electrically connects the sensing electrode ring (402) when the knob (30, 70) rotates to a first angle, and the common electrode ring (412) does not contact the connecting post (406) when the knob (30, 70) rotates to a second angle.
  11. The knob (30, 70) of claims 9-10, characterized in that the sensing electrode ring (402) is fixed on the touch panel (300) and the common electrode ring (412) rotates with the knob (30, 70) when the knob (30, 70) rotates.
  12. The knob (30, 70) of claims 9-10, characterized in that the common electrode ring (412) is fixed on the touch panel (300) and the sensing electrode ring (402) rotates with the knob (30, 70) when the knob (30, 70) rotates.
  13. A sensing circuit (1100), coupled to a knob (30, 70), characterized by the sensing circuit (1100) comprising: a receiving circuit (1102) to receive a signal variation (VRX) from the knob (30, 70); and a processing circuit (1104), coupled to the receiving circuit (1102), to determine a rotation direction of the knob (30, 70) according to the signal variation (VRX); wherein the signal variation (VRX) is received through a first touch sensor (S1) aligned with and coupled to a sensing electrode (RX) of the knob (30, 70); wherein the signal variation (VRX) is generated according to whether the sensing electrode (RX) is conducted with a first common electrode (COM1) and a second common electrode (COM2) in the knob (30, 70).
  14. The sensing circuit (1100) of claim 13, characterized in that the knob (30, 70) comprises the only one sensing electrode (RX).
  15. The sensing circuit (1100) of claims 13-14, characterized in that a second touch sensor (S2) corresponding to the first common electrode (COM1) and a third touch sensor (S3) corresponding to the second common electrode (COM2) are applied with a first reference voltage and a second reference voltage, respectively, to generate the signal variation (VRX).
  16. The sensing circuit (1100) of claim 15, characterized in that at least one of the first reference voltage and the second reference voltage is a ground voltage.
  17. The sensing circuit (1100) of claims 15-16, characterized in that at least one of the first reference voltage and the second reference voltage is from a touch object operating the knob (30, 70).
  18. The sensing circuit (1100) of claims 13-17, characterized in that the processing circuit (1104) further determines whether the knob (30, 70) is pressed according to the signal variation (VRX).

Description

Field of the Invention The present invention relates to a knob sensing technique, and more particularly, to a sensing technique for a knob on a touch panel. Background of the Invention Touch functions gradually become popular in vehicles' center information display (CID) systems. When environmental settings of a car (such as the temperature of air conditioning and the volume of car audio) need to be adjusted, the driver must focus more on the touch position and relevant settings displayed on the screen, thus affecting driving safety. In order to improve driving safety, a knob on a touch panel may be applied in the CID system, where a physical knob is disposed on the touch screen. Therefore, the driver can easily adjust the settings by controlling the knob without being distracted by the displayed values. Summary of the Invention The present invention therefore provides a knob on a touch panel and related sensing circuit, in order to improve the driving safety in vehicle applications. This is achieved by a knob according to independent claim 1 or by a sensing circuit according to independent claim 13. The dependent claims pertain to corresponding further developments and improvements. As will be seen more clearly from the detailed description following below, a knob, which is disposed on a touch panel comprising a first touch sensor, a second touch sensor and a third touch sensor, comprises a bottom surface and a first connector. The bottom surface comprises a sensing electrode, which is aligned with the first touch sensor; a first common electrode, which is aligned with the second touch sensor and receives a first reference voltage from the second touch sensor; and a second common electrode, which is aligned with the third touch sensor and receives a second reference voltage from the third touch sensor. The first connector controls the sensing electrode to be conducted with the first common electrode and the second common electrode or not when the knob rotates. A touch sensing circuit of the touch panel determines a rotation direction of the knob according to a signal variation of the first touch sensor. In another aspect, a sensing circuit coupled to a knob comprises a receiving circuit and a processing circuit. The receiving circuit receives a signal variation from the knob. The processing circuit, coupled to the receiving circuit, determines a rotation direction of the knob according to the signal variation. The signal variation is received through a first touch sensor aligned with and coupled to a sensing electrode of the knob, and the signal variation is generated according to whether the sensing electrode is conducted with a first common electrode and a second common electrode in the knob. Brief Description of the Drawings FIG. 1 is a schematic diagram of the bottom of a knob.FIG. 2 is a schematic diagram of another knob.FIG. 3 is a schematic diagram of a knob according to an embodiment of the present invention.FIG. 4 illustrates the detailed structure of electrode rings of the sensing electrode and the common electrodes in a disassembled manner.FIG. 5 and FIG. 6 illustrate the side view of the electrode ring arrangement in the knob shown in FIG. 3.FIG. 7 is a schematic diagram of another knob according to an embodiment of the present invention.FIG. 8 illustrates the detailed structure of electrode rings of the sensing electrode and the common electrodes in a disassembled manner.FIG. 9 and FIG. 10 illustrate the side view of the electrode ring arrangement in the knob shown in FIG. 7.FIGs. 11-14 illustrate the sensing systems in which the knob is in 4 different states, respectively.FIG. 15 illustrates the correspondence of the equivalent capacitance and the sensing signal.FIG. 16 is a schematic diagram of the rotation operation of the knob corresponding to different states.FIG. 17 is a schematic diagram of the press operation of the knob corresponding to different states.FIG. 18 illustrates the knob state determined according to the correspondence of the equivalent capacitance and the sensing signal with threshold values.FIG. 19 is a schematic diagram of the signal distribution on the touch sensor corresponding to the sensing electrode according to an embodiment of the present invention.FIG. 20 is a schematic diagram of a conductor of a knob according to an embodiment of the present invention. Detailed Description FIG. 1 is a schematic diagram of the bottom of a knob 10. As shown in FIG. 1, the knob 10 may be attached on a touch panel. The bottom of the knob 10 includes an electrode RA. The position of the electrode RA may change by turning the knob 10. When a user contacts the knob 10, the voltage of the electrode RA may become the ground level through the knob 10 and the user. When the sensing circuit of the touch panel senses that the user is turning the knob 10 through the touch electrodes on the touch panel, the sensing circuit may determine the rotation direction and angle θ of the knob 10 based