Device, system and method for changing the direction of emitted light cones

An optical system (500) comprising:

• a combiner (510);
• and
• an image generator device (100),
• wherein:
• the image generator device (100) comprises an image generator (130) and a fibre optical faceplate (110) having a first (112) and a second surface (113),
• the second surface (113) is a curved or freeform surface, the fibre optical faceplate (110) being arranged to transmit light from the image generator (130) so at least a part of light entering the first surface (112) of the fibre optical faceplate (110) exits through the second surface (113) of the fibre optical faceplate (110),
• the fibre optical faceplate (110) comprises a multitude of optical fibres (111) and light exiting the second surface (113) through optical fibres (111) each form an emitted light cone,
• a surface structure (120) is arranged at the second surface (113) of the fibre optical faceplate (110) the surface structure (120) being at least one of:
• a geometry engraved or etched into the second surface (113), or
• a structure separate from and positioned on top of the second surface (113), the structure being deposited by one of:
• photolithography, molding on top of the second surface, machining into a material separately deposited on top of the second surface, or three-dimensionally printed on top of the second surface, and the surface structure (120) comprises at least one step structure (121) that alters a surface normal of the second surface (113) to be constant across an entirety of the second surface (113), such that the surface structure (120) is arranged to, by refraction, change the direction of at least one emitted light cone of light exiting the second surface (113) towards an eye box (520) via the combiner (510).

A method (700) for changing the direction of at least one emitted light cone, the method comprising:

• transmitting (710) light from an image generator (130) to a first surface (112) of a fibre optical faceplate (110), whereby forming a generated image plane at the first surface (112) of the fibre optical faceplate (110),
• transmitting (720) at least part of the light entering the first surface (112) of the fibre optical faceplate (110) to a curved or freeform second surface (113) of the fibre optical faceplate (110), whereby for each at least one fibre (111) of the fibre optical faceplate (110) an emitted light cone of light exiting the second surface (113) is formed,
• generating (730) a transformed generated image plane at the second surface (113) of the fibre optical faceplate (110), and
• changing (740) by refraction the direction of the at least one emitted light cone of light exiting the fibre optical faceplate (110) through the second surface (113) towards an aperture (220;520), said changing occurring via a surface structure (120) arranged at the second surface (113) of the fibre optical faceplate (110), the surface structure (120) comprising at least one step structure (121) that alters a surface normal of the second surface (113) to be constant across an entirety of the second surface (113), such that the surface structure (120) and being at least one of:
• a geometry engraved or etched into the second surface (113), or
• a structure separate from and added on top of the second surface (113), the structure being deposited by one of:
• photolithography, molding on top of the second surface, machining into a material separately deposited on top of the second surface, or three-dimensionally printed on top of the second surface.