Varifocal display with actuated reflectors

A non-transitory computer readable medium configured to store program code instructions, when executed by a processor, cause the processor to perform steps comprising:

• determining a position and an orientation of a head-mounted display (HMD) worn by a user, the HMD including an electronic display, a front optical element, and a back optical element that is between the front optical element and the electronic display;
• determining a portion of a virtual scene based on the determined position and orientation of the HMD;
• displaying the determined portion of the virtual scene being on the electronic display of the HMD;
• determining an eye position for each eye of the user using an eye tracking module;
• determining a vergence depth based on an estimated intersection of gaze lines corresponding to the determined eye position for each eye;
• and
• adjusting an optical power of the HMD based on the determined vergence depth by simultaneously adjusting a position of the back optical element with respect to the electronic display at a first rate of adjustment and adjusting a position of the front optical element with respect to the electronic display with the back optical element between the front optical element and the electronic display at a second rate of adjustment that is a same as the first rate of adjustment to vary an adjustable distance between the back optical element and the front optical element in accordance with the vergence depth.

A method comprising:

• determining a position and an orientation of a head-mounted display (HMD) worn by a user, the HMD including an electronic display, a front optical element, and a back optical element that is between the front optical element and the electronic display, the back optical element including a reflective polarizer surface and a waveplate surface that is opposite to the reflective polarizer surface and spaced apart from the reflective polarizer surface by one or more side surfaces of the back optical element that are connected to the reflective polarizer surface and the waveplate surface, the reflective polarizer surface configured to reflect linearly polarized light having a first polarization, and transmit linearly polarized light having a second polarization that is orthogonal to the first polarization, and the waveplate surface configured to shift a polarization state of light received from the reflective polarizer surface;
• determining a portion of a virtual scene based on the determined position and orientation of the HMD;
• displaying the determined portion of the virtual scene being on the electronic display of the HMD;
• determining an eye position for each eye of the user using an eye tracking module;
• determining a vergence depth based on an estimated intersection of gaze lines corresponding to the determined eye position for each eye;
• and
• adjusting an optical power of the HMD based on the determined vergence depth by simultaneously adjusting a position of the back optical element with respect to the electronic display and adjusting a position of the front optical element with respect to the electronic display to vary an adjustable distance between the back optical element and the front optical element in accordance with the vergence depth.