1. Field of the Invention
The present invention relates to a sensing device, a control method thereof, and a recording medium.
2. Description of the Related Art
Due to the recent proliferation of electronic devices, such as smart phones, the development of technologies relating to sensing functions/operations of a touch screen mounted in the smart phones has steadily increased. In order to input a specific command in relation to a smart phone or a touch screen, a user may input the specific command or designate a specific icon by touching with a finger or a stylus pen using an Electromagnetic Induction (EI) (hereinafter, electromagnetic induction pen) to a specific location of the touch screen.
In order to utilize the stylus pen using electromagnetic induction, a loop coil is disposed in the electronic device, and a control is made such that voltage is applied to the loop coil to generate an electromagnetic field that is transferred to the electromagnetic induction pen. The electromagnetic induction pen includes a capacitor and a loop, and converts the transferred electromagnetic field into an electromagnetic field having a predetermined frequency component to be re-discharged.
The discharged electromagnetic field from the electromagnetic induction pen is re-transferred to the loop coil of the circuit board, which makes it possible to determine a location where the electromagnetic induction pen closely approaches the touch screen.
In conventional electromagnetic induction methods, channels for processing input and output signals have to be assigned to all loop coils included in a circuit board of an electronic device in order to apply an electromagnetic field to the electromagnetic induction pen. When a plurality of loop coils exists on the circuit board, a plurality of channels are required, which leads to an increase in the amount of calculation for processing signals from the plurality of channels. In addition, a high-performance processor may be required to process the increasing calculation, which is burdensome on firmware.
Furthermore, when a touch location is determined through the electromagnetic induction methods, if the area of a display for which the touch screen is employed increases, such as an electronic bulletin board, the strength of signals decreases toward the central portion of the touch screen due to the arrangement of multiple coils, rendering it difficult to accurately determine the touch location.