Head-mounted viewable device and eye-tracking system for use in head-mounted viewable device

A head-mounted viewable device, comprising:

• a display configured for displaying and projecting a virtual scene image to at least one eyeball of the user who is wearing said head-mounted viewable device;
• a VR (Virtual Reality) optical lens configured to form an optical path between said display and the one or more eyeballs of the user for allowing said virtual scene image being displayed at and projected from said display to reach the eyeball of the user through said VR optical lens;
• and
• an eye-tracking system configured to detect a sight direction of the eyeball of the user and adjust a display position of said virtual scene image at said display according to said detected sight direction, wherein said eye-tracking system comprises:
• at least one light source configured to project a detection light to the one or more eyeballs of the user;
• and
• a receiving module configured to receive said detection light reflected by the eyeball of the user so as to detect said sight direction of the eyeball of the user, wherein said receiving module is positioned at a side of said VR optical lens for facing towards the eyeball of the user, such that said detection light reflected by the eyeball of the user is directly received by said receiving module, wherein said receiving module comprises an optical lens unit and a photosensitive element, wherein said optical lens unit comprises at least one optical lens configured for receiving said detection light reflected by the eyeball of the user, wherein a plane defined by said photosensitive element and a plane defined by said at least one optical lens have an including angle defined therebetween, wherein said including angle between said plane defined by said photosensitive element and said plane defined by said at least one optical lens is determined based on an included angle defined between an object optical axis defined by the eyeball of the user and a detecting optical axis defined by said receiving module, as well as optical parameters of said at least one optical lens, wherein said included angle between the object optical axis defined by the eyeball of the user and the detecting optical axis defined by said receiving module is determined based on a distance between the eyeball of the user and said VR optical lens, a predetermined diameter of the respective eyeball of the user, and a distance between said VR optical lens and said receiving module, wherein said included angle between the object optical axis defined by the eyeball of the user and the imaging optical axis defined by said receiving module is ranged 25.0° to 40.0°.