Eyeball tracking optical system and head-mounted device

An eyeball tracking optical system, comprising a light source module, a fixed-lens group module, a prism module, and an image acquisition module;

• the light source module is located at an edge of a side of the fixed-lens group module close to a user's eyeball, and is configured to emit a light ray with a preset wavelength to the user's eyeball;
• the light ray with the preset wavelength forms a reflected light ray after being reflected by the user's eyeball;
• the fixed-lens group module at least comprises a first fixed-lens and a second fixed-lens, the first fixed-lens and the second fixed-lens being sequentially arranged along a side far away from the user's eyeball, and the image acquisition module being located at an edge of a gap side between the first fixed-lens and the second fixed-lens;
• the prism module comprises at least one reflection prism, the at least one reflection prism being located at a front end of a light-sensitive surface of the image acquisition module;
• the reflected light ray penetrates through the first fixed-lens, is reflected by the second fixed-lens, then is reflected by the at least one reflection prism, and then enters the image acquisition module, and the image acquisition module is configured to generate an image of the user's eyeball.