Electronic device including power-on button and inductive touch force sensor

An inductive force sensor comprising:

• a second part including a plurality of separated areas configured to be exposed to an external force in a Z-axis direction and to be elastically deformable along the Z-axis direction by the external force in the Z-axis direction;
• a plurality of inductive coils formed on a substrate that is spaced apart from the second part, and disposed to correspond to the plurality of separated areas and to face the plurality of separated areas respectively;
• a first channel resonance circuit coupled to a first inductive coil of the plurality of inductive coils, and configured to have a first resonant frequency attributable to first inductance due to the first inductive coil based on a first displacement of a first separated area relative to the first inductive coil;
• a first oscillator configured to apply a first AC signal to the first channel resonance circuit;
• a second channel resonance circuit coupled to a second inductive coil of the plurality of inductive coils, and configured to have a second resonant frequency attributable to second inductance due to the second inductive coil based on a second displacement of a second separated area relative to the second inductive coil;
• a second oscillator configured to apply a second AC signal to the second channel resonance circuit;
• a reference resonance circuit configured to have same impedance as a predetermined first state of states that the first channel resonance circuit has and a predetermined second state of states that the second channel resonance circuit has;
• a reference oscillator configured to:
• have same characteristics as the first oscillator and the second oscillator;
• and
• apply a reference AC signal to the reference resonance circuit;
• and
• a determination circuit configured to:
• receive a first electric signal formed in the first channel resonance circuit, a second electric signal formed in the second channel resonance circuit, and a reference electric signal formed in the reference resonance circuit;
• and
• determine the first displacement, the second displacement, a location at which the external force in the Z-axis direction has been input, and the external force based on the first resonant frequency of the first electric signal, the second resonant frequency of the second electric signal, and a reference resonant frequency of the reference electric signal.

A method of operating an inductive force sensor, the inductive force sensor comprising a first part configured to be exposed to an external force in a Z-axis direction and to be elastically deformable along the Z-axis direction by the external force in the Z-axis direction and an inductive coil formed on a substrate that is spaced apart from the first part;

• the method comprising:
• applying, by a first oscillator, a first AC signal to a first resonance circuit that is coupled to the inductive coil and has a first resonant frequency attributable to first inductance due to the inductive coil based on a displacement of the first part relative to the inductive coil;
• applying, by a reference oscillator having same characteristics as the first oscillator, a reference AC signal to a reference resonance circuit that has same impedance as a predetermined first state of states that the first resonance circuit can have;
• receiving, by a determination circuit, a first electric signal that is formed in the first resonance circuit by an influence of the first AC signal;
• receiving, by the determination circuit, a reference electric signal that is formed in the reference resonance circuit;
• and
• determining, by the determination circuit, a displacement of the first part and the external force in the Z-axis direction based on the first resonant frequency of the first electric signal and a reference resonant frequency of the reference electric signal.

A method of operating an inductive force sensor, the inductive force sensor comprising a second part including a plurality of separated areas configured to be exposed to an external force in a Z-axis direction and to be elastically deformable along the Z-axis direction by the external force in the Z-axis direction and a plurality of inductive coils formed on a substrate that is spaced apart from the second part and disposed to correspond to the plurality of separated areas and to face the plurality of separated areas respectively, the method comprising:

• applying, by a first oscillator, a first AC signal to a first channel resonance circuit coupled to a first inductive coil of the plurality of inductive coils and configured to have a first resonant frequency attributable to first inductance formed in the first inductive coil based on a first displacement of a first separated area relative to the first inductive coil;
• applying, by a second oscillator, a second AC signal to a second channel resonance circuit coupled to a second inductive coil of the plurality of inductive coils and configured to have a second resonant frequency attributable to second inductance formed in the second inductive coil based on a second displacement of a second separated area relative to the second inductive coil;
• applying, by a reference oscillator configured to have same characteristics as the first and second oscillators, a reference AC signal to a reference resonance circuit configured to have same impedance as a predetermined first state of states that the first channel resonance circuit has and a predetermined second state of states that the second channel resonance circuit has;
• receiving, by a determination circuit, a first electric signal formed in the first channel resonance circuit;
• receiving, by the determination circuit, a second electric signal formed in the second channel resonance circuit;
• receiving, by the determination circuit, a reference electric signal formed in the reference resonance circuit;
• and
• determining, by the determination circuit, the first displacement, the second displacement, a location at which the external force in the Z-axis direction has been input, and the external force based on the first resonant frequency of the first electric signal, the second resonant frequency of the second electric signal, and a reference resonant frequency of the reference electric signal.

An electronic device comprising:

• an enclosure configured to surround an interior of the electronic device;
• a first area disposed on the enclosure, and configured to operate as a power-on button;
• a plurality of second areas arranged to be elastically deformable in a Z-axis direction by an external force applied in the Z-axis direction in remaining areas of the enclosure excluding the first area;
• a pressure-sensing variable resistor disposed in the first area, and configured to respond to pressure from an outside;
• a power-on button on/off sensing circuit connected to the pressure-sensing variable resistor and an internal power of the electronic device;
• a plurality of inductive coils formed on a substrate that is spaced apart from the plurality of second areas inside the electronic device, and disposed to be opposite to the plurality of second areas, respectively;
• a plurality of individual channel resonance circuits coupled to the plurality of inductive coils, respectively, and configured to have individual channel resonant frequencies attributable to individual channel inductances formed in the plurality of inductive coils based on individual channel displacements of the plurality of second areas in the Z-axis direction relative to the plurality of inductive coils;
• a reference resonant circuit configured to have same impedance as a predetermined first state of states that the plurality of individual channel resonant circuits has;
• and
• a determination circuit configured to:
• receive a reference electric signal formed in the reference resonance circuit by an influence of a reference AC signal applied to the reference resonance circuit and a plurality of individual channel electric signals formed in the plurality of individual channel resonance circuits by an influence of individual channel AC signals applied to the plurality of individual channel resonance circuits;
• and
• determine the individual channel displacements, locations at which external forces applied in the Z-axis direction have been input in the plurality of second areas and the external forces applied in the Z-axis direction based on a reference resonant frequency of the reference electric signal and individual channel resonant frequencies of the plurality of individual channel electric signals.