Patent Description:
Head-Mounted Displays (HMDs), which include monocular and binocular near eye displays, are being developed for a range of diverse uses, including military, commercial, industrial, fire-fighting, and entertainment applications. In conventional HMDs, both immersive and transparent to the real world, virtual images are formed that must be positioned relative to a user's eye. Furthermore, there is a need to be able to position the virtual image so that it does not obstruct the user's field of view.

In order to form a virtual image at an intended position for a viewer, the optical apparatus must satisfy various geometric and positional requirements. These requirements often impact design and usability factors such as viewer position and placement of the optical system relative to the eye of the viewer. The optical system, for example, may not be able to position the virtual image at precisely the position at which it would be most useful for a particular viewer or purpose due to anatomical variations between viewers. The viewer may want the virtual image content available within the field of view, but may not want image content directly superimposed onto, and partially obscuring, real-world objects in the field of view. Or, in a partially occluded system, the viewer may want to position the virtual image in an upper portion of the field of view so that hands are visible in a lower portion. Rigid constraints typical of a number of previous HMD optics designs can make the HMD system awkward to use for practical functions.

Furthermore, proper positioning of an image has both lateral and angular aspects and these can be interrelated, so that an adjustment in one direction affects other adjustments. Simply repositioning an HMD higher on the viewer's head may not be sufficient for repositioning the image that is formed and may even cause the exiting rays from the HMD to miss the viewer's pupil entirely. Similarly, tilting an HMD without any lateral movement may make it impossible to view the virtual image.

Mechanical adjustments provided for existing HMD systems may allow a measure of adjustment, but are often awkward and difficult for the viewer to adjust without assistance.

Thus, it can be appreciated that there would be practical utility in methods and apparatus that provide some measure of flexibility in placement of optical components used for virtual imaging, allowing adjustment in placement of the virtual image itself. It would be advantageous to allow flexible placement with relation to the three orthogonal linear dimensions, as well as to the three angular dimensions, and to provide this capability within a compact form factor.

<CIT> discloses a display unit coupled with a telescopic arm via a first connection mechanism. The first connection mechanism is a spherical coupling mechanism having three degrees of freedom. The display unit is coupled with a head holding member via a second connection mechanism. The second connection mechanism comprises a convex spherical portion coupled with an ear pad of the head holding member, a concave spherical portion, and a screw passing through the concave spherical portion and the convex spherical portion and threaded with a block.

<CIT> discloses a display unit having an arm, composed of two hollow pipes, connected to a head holding member via a second connection mechanism. The arm forms a sliding for adjusting the length of the arm in a long side direction.

Head-set display devices are disclosed in <CIT> and <CIT>.

<CIT> discloses a head-mounted display device which has a first casing, a second casing, and a coupling portion for movably coupling the second casing to the first casing.

It is an object of the present disclosure to advance the art of image presentation within compact head-mounted (near-eye) displays. In addition, it would be advantageous to provide a design that allows the viewer to manually adjust the relative position of the virtual image content without removing the wearable display and without interrupting visibility of the virtual content display.

This object is solved by the adjustable imaging apparatus of claim <NUM>. Preferred embodiments of the apparatus are subject-matter of claims <NUM> to <NUM>.

These and other aspects, objects, features and advantages of the present invention will be more clearly understood and appreciated from a review of the following detailed description of the preferred embodiments and appended claims, and by reference to the accompanying drawings.

According to an aspect of the present disclosure, there is provided an adjustable imaging apparatus including a support that mounts a display apparatus against the head of a viewer. A ball joint is fitted within the support and coupled to a clamp that extends from the support. A slide is translatable within the clamp in a first direction and holds a display module for forming the display image. A display coupled to the display module and rotatable in a first arc about a vertical axis extends in a second direction that is orthogonal to the first direction and further rotatable in a second arc about a horizontal axis that is substantially orthogonal to the vertical axis.

While the specification concludes with claims particularly pointing out and distinctly claiming the subject matter of the present invention, it is believed that the invention will be better understood from the following description when taken in conjunction with the accompanying drawings.

The present description is directed in particular to elements forming part of, or cooperating more directly with, apparatus in accordance with the invention. It is to be understood that elements not specifically shown or described may take various forms well known to those skilled in the art.

Where they are used herein, the terms "first", "second", and so on, do not necessarily denote any ordinal, sequential, or priority relation, but are simply used to more clearly distinguish one element or set of elements from another, unless specified otherwise. The terms "top" and "bottom" do not necessarily designate spatial position but provide relative information about a structure, such as to distinguish opposing surfaces of a planar (flat) waveguide.

In the context of the present disclosure, the terms "viewer", "operator", "observer", and "user" are considered to be equivalent and refer to the person who wears the HMD viewing device.

As used herein, the term "energizable" relates to a device or set of components that perform an indicated function upon receiving power and, optionally, upon receiving an enabling signal.

The term "actuable" has its conventional meaning, relating to a device or component that is capable of effecting an action in response to a stimulus, such as in response to an electrical signal, for example.

The term "set", as used herein, refers to a non-empty set, as the concept of a collection of elements or members of a set is widely understood in elementary mathematics. The term "subset", unless otherwise explicitly stated, is used herein to refer to a non-empty proper subset, that is, to a subset of the larger set, having one or more members. For a set S, a subset may comprise the complete set S. A "proper subset" of set S, however, is strictly contained in set S and excludes at least one member of set S.

In the context of the present disclosure, the term "oblique" means at an angle that is not an integer multiple of <NUM> degrees. Two lines, linear structures, or planes, for example, are considered to be oblique with respect to each other if they diverge from or converge toward each other at an angle that is at least about <NUM> degrees or more away from parallel, or at least about <NUM> degrees or more away from orthogonal.

In the context of the present disclosure, the terms" wavelength band" and "wavelength range" are equivalent and have their standard connotation as used by those skilled in the art of color imaging and refer to a range of light wavelengths that are used to form one or more colors in polychromatic images. Different wavelength bands are directed through different color channels, such as to provide red, green, and blue primary colors in conventional color imaging applications.

As an alternative to real image projection, an optical system can produce a virtual image display. In contrast to methods for forming a real image, a virtual image is not formed on a display surface. That is, if a display surface were positioned at the perceived location of a virtual image, no image would be formed on that surface. A virtual image display has a number of inherent advantages for an augmented reality display. For example, the apparent size of a virtual image is not limited by the size or location of a display surface. Additionally, the source object for a virtual image may be small; a magnifying glass, as a simple example, provides a virtual image of its object. In comparison with systems that project a real image, a more realistic viewing experience can be provided by forming a virtual image that appears to be some distance away. Providing a virtual image also obviates any need to compensate for screen artifacts, as may be necessary when projecting a real image.

In the context of the present disclosure, the term "coupled" is intended to indicate a physical association, connection, relation, or linking, between two or more components, such that the disposition of one component affects the spatial disposition of a component to which it is coupled. For mechanical coupling, two components need not be in direct contact, but can be linked through one or more intermediary components. A component for optical coupling allows light energy to be input to, or output from, an optical apparatus. The terms "beam expander" and "pupil expander" are considered to be synonymous, used interchangeably herein.

The perspective views of <FIG> and <FIG> show an adjustable imaging apparatus <NUM> that allows viewer adjustment of the position of a displayed image with respect to all three translational axes and all three rotational axes. A portion of a head mount <NUM> is shown in <FIG>, with various features that are used to fit head mount <NUM> against the head of the viewer and allow the adjustment of the position of an image display <NUM> relative to the eye of a viewer. Display <NUM> is provided at the end of a display module <NUM>. A slide <NUM>, coupled to mount <NUM> by a ball joint <NUM>, allows translation of display module <NUM> along an axis extending forward of the viewer. Optics and components of projector <NUM> are fitted within the display module <NUM>. A display mount <NUM> then provides rotation about a number of axes as indicated.

<FIG>, <FIG>, <FIG>, and <FIG> are schematic views that show how imaging apparatus <NUM> can be adjusted for various positions of display <NUM>, relative to mutually orthogonal X, Y, and Z coordinate axes, and show corresponding axial rotations. A ball joint <NUM>, shown in more detail subsequently, allows pitch adjustment as well as elevation adjustment and horizontal displacement for variable positioning of imaging light guide mount <NUM> to suit the head size of the viewer, with translational motion along the X axis and Y axis. Z axis translation of display module <NUM>, in a forward direction with respect to the viewer, is provided by slide <NUM>, as noted previously. Head mount <NUM> can be positioned along the head of the viewer using conventional methods, such as a strap arrangement or can be mounted in a helmet, as part of a frame, or as part of other headgear. A vertical hinge <NUM> allows rotation about vertical axis Y, which is substantially orthogonal to the forward direction defined by slide <NUM>. A horizontal hinge <NUM> allows rotation about horizontal axis X, which is substantially orthogonal to vertical axis Y.

For roll adjustment of the display <NUM> about the X axis, <FIG> shows rotation using horizontal hinge <NUM>. Rotation about horizontal hinge <NUM> shifts the relative position of a virtual image in the vertical direction. Where a real image is formed, horizontal hinge <NUM> allows movement of the real image in the roll direction, as shown in <FIG>.

For yaw adjustment, <FIG> shows rotation about the Y axis using vertical hinge <NUM>. Movement is thus about an axis that is substantially orthogonal to the motion about the X axis. Rotation about vertical hinge <NUM> shifts the relative position of a virtual image in the horizontal direction.

<FIG> shows an elevation adjustment for display mount <NUM> by pivoting from ball joint <NUM>.

It should be noted that the adjustments described with respect to <FIG>, and related adjustments, change the relative position of a real image formed on display <NUM> or, alternately, of a virtual image that appears in the viewer eye box.

<FIG> is a close-up perspective view that shows components of display mount <NUM> according to an embodiment.

<FIG> is a perspective view showing a portion of head mount <NUM> for an imaging apparatus <NUM> according to an embodiment. A clamp <NUM> is provided as a guide for holding the display module <NUM> (not shown in <FIG> for better visibility of the clamp <NUM>). Clamp <NUM> is coupled to head mount <NUM> by ball joint <NUM>. Clamp <NUM> allows the display module <NUM> to be separable from the head mount <NUM> arrangement.

<FIG> is a close-up perspective view showing clamp <NUM> and a cross-section of ball joint <NUM>.

<FIG> show, from a rear perspective view, how clamp <NUM> can be coupled to display module <NUM>.

<FIG> are close-up perspective views showing an alternate arrangement for clamp <NUM> in a configuration using eyeglass frame <NUM>.

<FIG> is a close-up perspective view of an alternate embodiment with a bracket <NUM> that attaches imaging apparatus <NUM> to a helmet.

<FIG> is an alternate embodiment that shows an imaging apparatus <NUM> that uses an optical waveguide <NUM> for forming a virtual image from a projector <NUM>. The waveguide is hinged relative to the optics providing side to side adjustment of the virtual image. The hinge allowing vertical movement is positioned closer to the ball joint to allow for movement of the input projector.

Claim 1:
An adjustable imaging apparatus (<NUM>), comprising:
a display module (<NUM>) having an inner surface and an outer surface, wherein the display module (<NUM>) is operable to form an image;
a support (<NUM>) operable to mount the display module (<NUM>) along a head of a viewer;
a ball joint (<NUM>) at least partially located within the support (<NUM>);
a first hinge (<NUM>);
a second hinge (<NUM>);
a clamp (<NUM>) coupled with the ball joint (<NUM>), wherein the clamp (<NUM>) extends from the support (<NUM>) via the ball joint (<NUM>), and the clamp (<NUM>) is operable to pivot relative to the support (<NUM>) via the ball joint (<NUM>);
a slide (<NUM>) coupled with the inner surface of the display module (<NUM>), wherein the slide (<NUM>) is translatable within the clamp (<NUM>) in a first direction; and
a display (<NUM>) coupled with the display module (<NUM>), wherein the display (<NUM>) is rotatable about a vertical axis (Y), wherein the vertical axis (Y) extends in a second direction that is orthogonal to the first direction, and wherein the first hinge (<NUM>) is operable to enable rotation of the display (<NUM>) about the vertical axis (Y), wherein the first hinge (<NUM>) is positioned between the ball joint (<NUM>) and the display (<NUM>) along the first direction,
wherein the display (<NUM>) is rotatable about a horizontal axis (X) that is substantially orthogonal to the vertical axis (Y) and the first direction, wherein the second hinge (<NUM>) is operable to enable rotation of the display (<NUM>) about the horizontal axis (X), whereby a position of the image formed by the display module (<NUM>) is operable to move in two dimensions;
wherein the slide (<NUM>) is separable from the clamp (<NUM>) via translation of the display module (<NUM>) in the first direction.