Communication terminal apparatus and method for supplying terminal power source

1. A communication terminal comprising:

a display;

a battery;

a wireless communication interface configured to communicate with another communication terminal;

a power transmitting interface configured to transmit contactless electric power to the another communication terminal; and

circuitry configured to

determine, before the contactless electric power is transmitted to the another communication terminal and when an operation is performed in the communication terminal while the contactless electric power is transmitted to the another communication terminal, whether an amount of power remaining in the battery is larger than a predetermined amount;

control the wireless communication interface to transmit, to the another communication terminal, an instruction for receiving the contactless electric power transmitted from the power transmitting interface; and

control the display to display to a user the amount of power remaining in the battery at least one of before, during and after the contactless electric power is transmitted to the another communication terminal and, if it is determined, before the contactless electric power is transmitted to the another communication terminal or when the operation is performed in the communication terminal while the contactless electric power is transmitted to the another communication terminal, that the amount of power remaining is not larger than the predetermined amount, to prompt the user to confirm that the contactless electric power is to be transmitted to the another communication terminal.

2. The communication terminal of claim 1 , wherein the wireless communication interface is configured to communicate with the another communication terminal via a base station of a wireless communication network.

3. The communication terminal of claim 1 , wherein the wireless communication interface is configured to communicate with the another communication terminal via a short-range wireless link.

4. The communication terminal of claim 3 , wherein the short range wireless link is a wireless local area network (LAN) link, a near field communications (NFC) link, a Bluetooth link or an infrared link.

5. The communication terminal of claim 1 , wherein the power transmitting interface is configured to transmit the contactless electric power at a predetermined resonance frequency.

6. The communication terminal of claim 5 , wherein the circuitry is configured to control the wireless communication interface to transmit information indicating the predetermined resonance frequency to the another communication terminal as the instruction.

7. The communication terminal of claim 1 , wherein the power transmitting interface is configured to transmit the contactless electric power at a plurality of resonance frequencies that vary in multiple stages over time.

8. The communication terminal of claim 7 , wherein the circuitry is configured to control the wireless communication interface to transmit information indicating the plurality of resonance frequencies and the timing at which they vary in multiple stages over time as the instruction.

9. The communication terminal of claim 1 , wherein the power transmitting interface is configured to transmit the contactless electric power at a plurality of resonance frequencies that vary continuously over time.

10. The communication terminal of claim 9 , wherein the circuitry is configured to control the wireless communication interface to transmit information indicating the plurality of resonance frequencies and the timing at which they continuously vary over time as the instruction.

11. The communication terminal of claim 1 , further comprising:

a power receiving interface configured to receive contactless electric power.

12. The communication terminal of claim 11 , wherein the circuitry is configured to control a resonance frequency of the power receiving interface based on an instruction received via the wireless communication interface.

13. The communication terminal of claim 1 , wherein the another terminal is one of a mobile telephone, a wireless headset and a notebook personal computer (PC).

14. A power transfer method performed by a communication terminal, the method comprising:

determining, before contactless electric power is transmitted to another communication terminal and when an operation is performed in the communication terminal while the contactless electric power is transmitted to the another communication terminal, whether an amount of power remaining in a battery of the communication terminal is larger than a predetermined amount;

transmitting, from a wireless communication interface of the communication terminal to the another communication terminal, an instruction for receiving the contactless electric power transmitted from a power transmitting interface of the communication terminal;

transmitting, by the power transmitting interface of the communication terminal, the contactless electric power to the another terminal in accordance with the instruction;

displaying to a user an amount of power remaining in the battery of the communication terminal at least one of before, during and after the contactless electric power is transmitted to the another communication terminal; and

if it is determined, before the contactless electric power is transmitted to the another communication terminal or when the operation is performed in the communication terminal while the contactless electric power is transmitted to the another communication terminal, that the amount of power remaining is not larger than a predetermined amount, prompting the user to confirm that the contactless electric power is to be transmitted to the another communication terminal.

15. The method of claim 14 , wherein the contactless power is transmitted from the power transmitting interface at a predetermined resonance frequency.

16. The method of claim 14 , wherein the contactless power is transmitted from the power transmitting interface at a plurality of resonance frequencies that vary in multiple stages over time.

17. The method of claim 14 , wherein the contactless power is transmitted from the power transmitting interface at a plurality of resonance frequencies that vary continuously over time.

18. The method of claim 14 , further comprising:

receiving, at a power reception interface of the communication terminal, contactless electric power.