NB HINGE structure: sunken rotating shaft

The fixed point of the sinking shaft is located in the thick main engine part, which is not related to the thickness of A part. When notebooks entered the ultrabook era, in order to make notebooks more thin and light, rotating shaft manufacturers developed a sunken rotating shaft, the screen is no longer limited by the thickness of the body. The disadvantage is that due to the increase in the difficulty of design and production process, the screen is farther from the eye, and the opening and closing Angle of a large seam between the two faces is not large enough, which also reduces the number of interfaces of the notebook, but does not affect the user's yearning for mobile portability.