BACKGROUND OF THE INVENTION

Modern computing and display technologies have facilitated the development of systems for so-called “virtual reality” or “augmented reality” experiences, wherein digitally produced images or portions thereof are presented in a wearable device to a user in a manner wherein they seem to be, or may be perceived as, real. A virtual reality, or “VR,” scenario typically involves presentation of digital or virtual image information without transparency to other actual real-world visual input; an augmented reality, or “AR,” scenario typically involves presentation of digital or virtual image information as an augmentation to visualization of the actual world around the user.

The wearable device may include augmented and/or virtual reality glasses. The image can be displayed using image frames or raster scanned images. In a scanning image display system, each of the light beams defines the pixels of the image. By scanning the mirrors in two orthogonal axes, a two-dimensional field of view (FOV) can be created. The images can be projected onto the spectacle lens, which can include waveguide-based eyepieces and other optical elements, such as optical fibers. The image display systems can be mounted on each of the left and right side the glasses frames.

SUMMARY OF THE INVENTION

Conventional scanning image displays in a wearable device for virtual reality or augmented reality applications often have limited field of view, because the scanning mirror has limited range of scan motion and design constraints in the arrangement of optical elements. However, this arrangement can lead to a larger device size, which can be undesirable. Embodiments of the present invention provide scanning image display systems with large field of view while maintaining a small device form factor. In some embodiments, the larger field of view can be achieved by scanning multiple incoming light beams at the same time and combining the individual fields of view into a larger composite field of view.

Embodiments of the present invention relate generally to image display systems. According to some embodiments of the invention, an image display system includes a scanning mirror for receiving two or more incoming light beams and providing a plurality of reflected light beams. Each of the plurality of reflected light beams is configured to provide an image in a respective field of view. The image display system also includes a waveguide having an input coupling optical element and an output coupling optical element. The input coupling optical element is configured for coupling the plurality of reflected light beams into the waveguide. The output coupling optical element is configured for projecting a plurality of output light beams from the waveguide to form a projected image in a composite field of view.

According to some embodiments of the invention, an image display system includes an optical subsystem configured to emit a first light beam and a second light beam, wherein the first light beam illuminates a first portion of a composite field of view and the second beam illuminates a second portion of the composite field of view. A scanning mirror is positioned to intercept and reflect the first light beam and the second light beam. The system also has a waveguide with at least one input coupling optical element for receiving the first light beam and the second light beam into the waveguide. The waveguide also has an output coupling optical element for projecting a plurality of output light beams derived from the first light beam and the second light beam from the waveguide to illuminate the composite field of view.

In some embodiments, the image display system also includes two or more RGB (Red-Blue-Green) combiners disposed on an opposite side of the waveguide from the scanning mirror. The RGB combiners are configured to provide the two or more incoming light beams having different incident angles. The input coupling optical element is configured to allow the incoming light beams to pass through the waveguide to reach the scanning mirror. The input coupling optical element is also configured to couple the reflected light beams into the waveguide.

In some embodiments of the image display system, the two or more RGB combiners are disposed at different angles with respect to the scanning mirror to provide the two or more incoming light beams having different incident angles.

In alternative embodiments, the two or more RGB combiners are disposed at the same angle with respect to the scanning mirror, and the image display system further includes reflective optical elements to provide two or more light beams having different incident angles.

In some embodiments, the input coupling optical element is a polarization sensitive diffractive input coupling grating (ICG).

In some embodiments, the image display system also includes a polarization control element disposed between the scanning mirror and the waveguide to convert the incoming beam to a polarization for which the incoupling element is transmissive.

In some embodiments, the image display system also includes a polarization control element disposed between the waveguide and the two or more RGB combiners. The polarization element is configured to convert the incoming light beams to a first polarization state, and the scanning mirror is configured to convert the first circular polarization state to a second circular polarization state. The polarization sensitive input coupling optical element is configured to allow light of the first circular polarization state to pass through and is configured to couple light of the second circular polarization state into the waveguide.

In some embodiments, the image display system also includes two or more RGB combiners disposed on the same side as the waveguide relative the scanning mirror. The two or more RGB combiners provide the two or more incoming light beams having different incident angles. The image display system also includes a quarter wave plate disposed adjacent to the scanning mirror and a polarization sensitive beam splitter disposed between the quarter wave plate and the waveguide. The polarization sensitive beam splitter is configured to direct the two or more incoming light beams from the RGB combiners through the quarter wave plate towards the scanning mirror, and light beams reflected from the scanning mirror are configured to propagate through the quarter wave plate and the polarization sensitive beam splitter and coupled into the waveguide by the input coupling optical element.

According to some embodiments of the invention, an image display system includes a source of imagewise modulated light that outputs a collimated incoming light beam including multiple components differentiated by wavelength and/or polarization. The image display system also includes a scanning mirror with a diffractive surface for receiving the collimated incoming light beam and by diffraction angularly separating the beam components. Each of the plurality of reflected and diffracted beam components is configured to provide an image in a respective field of view. The image display system also includes a waveguide that has an input coupling optical element for coupling the plurality of reflected light beams into the waveguide, and an output coupling optical element for projecting a plurality of output light beams from the waveguide to form a projected image with a composite field of view.

According to some embodiments of the invention, an image display system includes a light source for providing a collimated incoming light beam, the collimated incoming light beam including multiple components. The system also includes a scanning mirror with a diffractive surface for receiving the collimated incoming light beam and for providing a plurality of reflectively diffracted light beams having different angles of diffraction. Each of the plurality of reflectively diffracted light beams is configured to illuminate a portion of a field of view (FOV). The system also includes a waveguide having an input coupling optical element for receiving the plurality of reflectively diffracted light beams into the waveguide, and an output coupling optical element for projecting a plurality of output light beams from the waveguide to form a projected image with a composite field of view (FOV). The plurality of output light beams is derived within the waveguide from the plurality of reflectively diffracted light beams.

In an embodiment of the above image display system, the multiple components can include components having different wavelengths. In another embodiment, the multiple components can include components having different polarization. In yet another embodiment, the multiple components can include a plurality of sets of red, green, and blue components.

In an embodiment of the above image display system, the input coupling optical element is polarization state selective.

In another embodiment, the scanning mirror is disposed on an opposite side from the light source with respect to the waveguide, and the input coupling optical element of the waveguide is configured to allow the collimated incoming light beam to pass through the input coupling element and the waveguide. The input coupling optical element is also configured to couple the plurality of reflectively diffracted light beams into the waveguide by diffracting the reflectively diffracted beam at an angle above a critical angle for the waveguide.

According to some embodiments of the invention, a method for providing a composite field of view includes directing at least two input light beams to a scanning mirror, and reflecting the at least two input light beams with the scanning mirror to provide at least two reflected beams. Each of the reflected beams provides a portion of the composite field of view. The method also includes receiving the at least two reflected beams in an eyepiece waveguide, and outputting a plurality of output light beams from the eyepiece waveguide to form a projected image in the composite field of view. The plurality of output light beams are derived from the at least two reflected light beams.

In an embodiment of the above method, the method also includes providing at least two Red-Blue-Green combiners disposed on an opposite side of the eyepiece waveguide from the scanning mirror and configured to direct the at least two input light beams at different incident angles on the scanning mirror. In this embodiment, directing the at least two input light beams to the scanning mirror includes directing the at least two light beams through the waveguide eyepiece.

In another embodiment, the method includes providing an input coupling optic element on the eyepiece waveguide. In this embodiment, directing the at least two input light beams to the scanning mirror includes directing the at least two light beams through the input coupling element. Receiving the at least two reflected beams in the eyepiece waveguide includes receiving the at least two reflected beams through the input coupling element.

In some embodiments, directing at least two input light beams to a scanning mirror includes reflecting at least one of the at least two input light beams to introduce an angular difference between the at least two input light beams.

In another embodiment, directing at least two input light beams to a scanning mirror comprises passing the at least two input light beams through a quarter wave plate.

According to some embodiments of the invention, a method for displaying an image includes impinging two or more input light beams on a scanning mirror at two or more angles. The method includes scanning the two or more input light beams to provide a plurality of reflected light beams. Each of the plurality of reflected light beams is configured to provide an image in a respective field of view (FOV). The plurality of reflected light beams is received in a waveguide, and the waveguide projects a plurality of output light beams from the waveguide to form a projected image in a composite field of view (FOV). In some embodiments of the method, the composite field of view is larger than the FOV provided by each of the two or more input light beams. The image in the composite FOV can be a tiled image including the images from each of the input light beams.

Additional features, benefits, and embodiments are described below in the detailed description, figures, and claims.

