The invention provides a method of improving a flotation separation process. When the freewheeling MOSFET is turned on during the switching operation of the converter, while the low-side and energy transfer MOSFETs are turned off, the inductor current circulates or \u201cfreewheels\u201d through the freewheeling MOSFET. Each of the L-shaped portions reduces movement of the wire hooks inside the metal frame reducing noise and wear. When the soft material element is in contact with the surface of the lens body, this surface changes its optical feature. The CMOS image sensor converts the analog signal into a digital signal using a pipelined analog to digital converter. The light source is coupled to the FPC board and provides input light for the light guiding plate.