Method for sensing biometric object

A method for sensing a biometric object using an electronic device, the electronic device including a liquid crystal display (LCD) and an optical sensing unit disposed under the LCD, the LCD including a display surface having a sensing region for the biometric object, and a color filter unit, a liquid crystal layer containing a plurality of liquid crystal molecules, and a backlight unit sequentially disposed under the display surface in such order, the method comprising steps of:

• (a) emitting a sensing light from the backlight unit upon the biometric object contacting the sensing region on the display surface, and allowing the sensing light to pass through the color filter unit and then reach and be reflected by the biometric object to return as a reflected light;
• and
• (b) controlling arrangement of the liquid crystal molecules located in a first region of the liquid crystal layer to define a first light path, the first region being underneath the sensing region of the display surface and corresponding in position to the color filter unit, and allowing the reflected light having predetermined wavelengths to pass through the color filter unit and the first light path to reach and be detected by the optical sensing unit.