Tunable attenuation of light transmission artifacts in wearable displays

A wearable display system, comprising:

• a frame, wearable by a user as eyewear, the frame housing an eyepiece stack having a world side and a user side opposite the world side, wherein during use a user positioned on the user side views displayed images delivered by the wearable display system via the eyepiece stack which augment the user's field of view of the user's environment;
• a tunable attenuator arranged on the world side of the of the eyepiece stack, the tunable attenuator comprising an electro-optic cell arranged between a pair of linear polarizers, wherein the electro-optic cell comprises a layer of a blue phase liquid crystal material;
• a camera module mounted to the frame and facing the world side;
• and
• an electronic processing module in communication with the tunable attenuator and the camera module, the electronic processing module being programmed to determine information about an angle of incidence of light from an ambient light source based on images captured by the camera module and to vary the attenuation of the tunable attenuator based on the angle of incidence, wherein for at least one state of the electro-optic cell, the tunable attenuator attenuates incident light such that all light having a wavelength in a wavelength range from 460 nm to 630 nm transmitted through the tunable attenuator has a transmission of greater than 10% compared to a transmission of normally incident light for angles of incidence of less than 50° and a transmission of less than 10% compared to the transmission of normally incident light for angles of incidence greater than 70°.

A method for displaying an image using a wearable display system, comprising:

• directing display light from a display towards a user through an eyepiece to project images in the user's field of view;
• determining a relative location between an ambient light source and the eyepiece;
• and
• adjusting an attenuation of ambient light from the ambient light source through the eyepiece such that all ambient light having a wavelength in a wavelength range from 460 nm to 630 nm has a transmission of greater than 10% compared to a transmission of normally incident light for angles of incidence of less than 50° and a transmission of less than 10% compared to the transmission of normally incident light for angles of incidence greater than 70°, and depending on the relative location between the ambient light source and the eyepiece, wherein the adjusting comprises, in order:
• polarizing the ambient light to provide polarized light,
• retarding the polarized light by a first amount to provide once retarded polarized light,
• polarizing the once retarded polarized light to provide twice polarized light,
• retarding the twice polarized light to provide twice retarded polarized light, and
• polarizing the twice retarded polarized light to provide thrice polarized light, an intensity of the thrice polarized light being attenuated relative to the ambient light.