Generally, the basic components of known magnetic sensors are a magnetization coil and a detection coil. When metal substances are put near a sensor, the magnetic field changes due to the electric eddy current generated for the one side nearest the metal substances. The above mentioned change of magnetic field affects detection coil output. This process is utilized to detect magnetism. The magnetic sensor, because of its structure, is not easily affected by heat, light, or the surface of matters for detection. Moreover, it is possible to make small and light magnetic sensors.
The weak magnetic sensor of the prior existing technology has included the following characteristics: the magnetic sensor has adopted highly permeable magnetic materials for its core component. The sensor is composed of a primary coil and a secondary coil. The primary coil senses magnetism while the secondary coil detects the degree of saturation. The secondary coil has a magnetic axis in two directions so it can obtain the vector difference axis. Thus, the magnetic direction of weak-field magnetism can be measured.
In the prior technology, the magnetic materials were processed with precision. Then, the primary and the secondary coil were made utilizing a known wire coil technology. The wire coil technology was applied according to the positioning accuracy of the copper wires covered with the insulator. However, some magnetic materials with high permeability required a specific precision process. Moreover, the need for a separate primary and secondary coil positioning processes caused the following problem: it was difficult to maintain a certain coil pressure as well as evenly maintain the positioning accuracy of coils. Thus, the range of both the degree of detection errors and the level of reception became uncertain. Therefore, it has not been possible to make a thin and small sensor in terms of the structure. The prior art was easily affected by surrounding factors such as broken wires.