Patent Application
20120075167
The present invention relates to a head-mounted display apparatus. More particularly, the present invention relates to a head-mounted display apparatus having a wireless controller that is physically detached from a head-mounted display
Head-mounted displays are widely used in gaming and training applications. Such head-mounted displays typically use electronically controlled displays mounted on a pair of glasses or a helmet with supporting structures such as ear, neck, or head pieces that are worn on a user's head. Displays are built into the glasses together with suitable optics to present electronic imagery to a user's eyes.
Most head-mounted displays provide an immersive effect in which scenes from the real world are obscured and the user can see, or is intended to see, only the imagery presented by the displays. Immersive displays can include cameras to capture images of the scene in front of the user so that this image information can be combined with other images to provide a combined image of the scene where portions of the scene image have been replaced to create a virtual image of the scene. In such an arrangement, the display area is opaque. Such displays are commercially available, for example from Vuzix Corporation.
Alternatively, some head-mounted displays provide a see-through display for an augmented-reality view in which real-world scenes are visible to a user but additional image information is overlaid on the real-world scenes. Such an augmented-reality view is provided by helmet-mounted displays found in military applications and by heads-up displays (HUDs) in the windshields of automobiles. In this case, the display area is transparent.
U.S. Pat. No. 6,829,095 describes a device with the head-mounted display 10 or augmented-reality display in a glasses format where image information is presented within the lens areas 12 of the glasses. The lens areas 12 of the glasses in this patent include waveguides to carry the image information to be displayed from an image source, with a built-in array of partially reflective surfaces to reflect the information out of the waveguide in the direction of the user's eyes.
It is important that head-mounted displays be portable and comfortable for users. Generally, a light weight and a small form factor are critical factors for user comfort. To enable a light-weight and a small form factor, it is helpful to reduce the size and weight of the various elements that make up the head-mounted display, including the control electronics and any power needed to drive the control electronics. There is a need, therefore, for an improved head-mounted display apparatus that reduces the physical size and weight of the head-mounted display.
In accordance with the present invention, there is provided a head-mounted display apparatus, comprising:
a head-mounted display, the head-mounted display including a viewing area that displays information to a user of the head-mounted display and including a display wireless communication circuit for receiving wireless control signals;
a controller including a controller wireless communication circuit, wherein the controller controls the information displayed in the head-mounted display by communicating the wireless control signals to the display wireless communication circuit with the controller wireless communication circuit and wherein the controller is physically separate from the head-mounted display; and
a distance-monitoring circuit in the controller or the head-mounted display that monitors the distance between the controller and the head-mounted display and, when the distance between the controller and the head-mounted display is greater than a pre-determined distance, initiating a range signal to the user.
In another aspect of the present invention, a head-mounted display apparatus, comprises:
a head-mounted display, the head-mounted display including a viewing area that displays information to a user of the head-mounted display and including a display wireless communication circuit for receiving wireless control signals; and
a controller physically separate from the head-mounted display and a controller wireless communication circuit, wherein the controller controls the information displayed in the head-mounted display by causing the wireless control signals to communicate from the control wireless communication circuit to the display wireless communication circuit
An important feature of the present invention, by having a head-mounted display having a physically separate controller, a more comfortable and efficient head-mounted display is provided and a head-mounted display device is responsive to different controllers in different locations thereby improving the versatility and utility of the head-mounted display.
The above and other objects, features, and advantages of the present invention will become more apparent when taken in conjunction with the following description and drawings, wherein identical reference numerals have been used, where possible, to designate identical features that are common to the figures, and wherein:
A wide variety of head-mounted displays are known in the art. The head-mounted displays include a microprojector or image scanner to provide image information, relay optics to focus and transport the light of the image information to the display device and a display device that is viewable by the user's eyes. Head-mounted displays can provide image information to one eye of the user or both eyes of the user. Head-mounted displays that present image information to both eyes of the user can have one or two microprojectors. Monoscopic viewing, in which the same image information is presented to both eyes, is done with head-mounted displays that have one or two microprojectors. Stereoscopic viewing typically requires a head-mounted display that has two microprojectors.
The microprojectors include image sources to provide the image information to the head-mounted display. A variety of image sources are known in the art including, for example, organic light-emitting diode (OLED) displays, liquid crystal displays (LCDs), or liquid crystal on silicon (LCOS) displays.
The relay optics can include refractive lenses, reflective lenses, diffractive lenses, holographic lenses or waveguides. For a see-through display, the display should permit at least a partial view of the ambient environment or scene outside the head-mounted display within the user's line of sight. Suitable displays known in the art in which a digital image is presented for viewing by a user include a device or surface including waveguides, polarized reflecting surfaces, partially reflecting surfaces, or switchable mirrors. The present invention concerns display devices that are useable as see-through displays and that are useable to present information to a user.
Referring to
The head-mounted display 10 includes a display wireless communication circuit 24 for receiving wireless control signals through a wireless communication channel 40 communicated from a controller wireless communication circuit 22 located in the controller 20. The controller 20 communicates information through controller wireless communication circuit 22 to the display wireless communication circuit 24 in the head-mounted display 10 to present information to the user. Wireless communication is enabled by a variety of technologies, including point-to-point radio communications, networked wireless communications such as WiFi, or other standard wireless communication methods such as Bluetooth.
The controller 20 can also be implemented as one component of another system, which is enabled to communicate with the head-mounted display 10 to integrate control of the head-mounted display 10 into the natural control mechanisms of the other system, for example steering-wheel-mounted controls in an automobile or other vehicle. Such a controller is integrated into large items or much smaller items limited only by the physical size required for the controller 20.
Because the head-mounted display 10 and the controller 20 are physically separate, they can become disassociated, i.e. one of the two elements is lost or separated from the other such that communication between them is not possible. To assist in preventing this eventuality, in another aspect of the present invention, a distance-monitoring circuit 52, 54 is located in the controller 20 or the head-mounted display 10, respectively, or both, that monitors the distance between the controller 20 and the head-mounted display 10 and, when the distance between the controller 20 and the head-mounted display 10 is greater than a pre-determined distance, initiates a range signal to the user. In another embodiment, the distance-monitoring circuits 52, 54 are included in the display wireless communication circuit 24, the controller wireless communication circuit 22, or both the display wireless communication circuit 24 and the controller wireless communication circuit 22. The distance-monitoring circuits 52, 54 can have mutually cooperative circuits.
In various embodiments of the present invention, the distance-monitoring circuits 52, 54 can include one or more of a variety of arrangements to monitor the distance between the controller 20 and the head-mounted display 10. In one embodiment, the distance-monitoring circuit measures a propagation delay for a wireless signal to be communicated from the controller 20 to the head-mounted display 10 or from the head-mounted display 10 to the controller 20. The distance-monitoring circuit can measure a propagation delay for a wireless signal to be communicated from the controller 20 to the head-mounted display 10 and back or from the head-mounted display 10 to the controller 20 and back. The elapsed time (subtracting any computational and circuit overhead) is indicative of the distance, since electromagnetic signals travel at approximately one foot per nanosecond. Circuits are known that enable measurements and switching times of substantially less than one nanosecond.
In an alternative embodiment of the present invention, the distance monitoring circuits 52, 54 include a global positioning satellite (GPS) unit. By locating a global positioning satellite unit 72 in the controller 20 and a global positioning satellite unit 74 in the head-mounted display 10, the positions of the controller 20 and the head-mounted display 10 can be determined and a comparison of the position of the controller 20 and the position of the head-mounted display 10 made. Thus, the relative distance between the controller 20 and the head-mounted display 10 can be found, within the accuracy of the GPS circuits and satellites. Circuitry for finding the distance between two positions is within the capability of those knowledgeable in the computing arts and can include, for example, comparative circuits, digital logic, and the like.
In yet another embodiment of the present invention, the distance-monitoring circuitry initiates a range signal when the controller 20 fails to communicate with the head-mounted display 10 or the head-mounted display 10 fails to communicate with the controller 20 when desired. In one embodiment, a point-to-point low-power, local electromagnetic transmission is used. When the distance between the controller and the head-mounted display is too great, the signal has too low a power and communication cannot occur, as is found for example in devices employing the Bluetooth standard. In an embodiment of the present invention, the controller 20 and the head-mounted display 10 periodically communicate with each other sending a ‘heartbeat’ signal to ensure mutual presence. The distance-monitoring circuitry initiates a range signal when it fails to receive some number of heartbeat signals in a row. The actual number used for various heartbeat systems can vary based on the reliability of the signal and the expected interference that can cause temporary failures to receive the heartbeat signal, or system design constraints.
In a further embodiment of the present invention, the head-mounted display 10 monitors the signal strength of the signal from the controller 20 and compares that with known expected strength for various distances between the controller 20 and the head-mounted display 10. Since signal strength is affected by battery strength, the circuit can adjust for current battery level in the controller 20 and in the head-mounted display 10. In such an embodiment, the controller 20 and the head-mounted display 10 can exchange information relating to battery strength as part of the data communicated between the display wireless communication circuit 24 and the controller wireless communication circuit 22. Circuitry for measuring signal strength and battery strength is within the capability of those knowledgeable in the computing arts and signal communication arts and can include, for example, comparative circuits, digital logic, and the like.
When the distance-monitoring circuitry determines that a pre-determined distance has been exceeded, a variety of range signals are employed to alert a user to the situation. In one embodiment of the present invention, an range signal 62, 64 in either the controller 20 or the head-mounted display 10, or both the controller 20 and the head-mounted display 10, is employed. The range signal 62, 64 is an audible range signal, such as a tone, tone sequence, musical sequence, or other audio signal. In one embodiment of the present invention, the range signal 62, 64 includes words, for example, words that explain the situation or give useful instruction to remedy the situation.
In an alternative embodiment of the present invention, the range signal 62, 64 is presented as information in the head-mounted display 10, for example, as written words that explain the situation or give useful instruction to remedy the situation. Alternatively, flashing lights or other visual cues are employed. In another embodiment, a visual signal is combined with an audio signal. In situations in which the controller 20 is not able to transmit information for display to the user, the range signal 64 and its control is provided in the head-mounted display 10.
In another embodiment of the present invention, the range signal 64 is presented as haptic feedback in the head-mounted display. For example, a control in the head-mounted display 10 can vibrate once or periodically while the controller 20 is outside the specified range. In another embodiment, haptic feedback is combined with a visual signal, an audio signal or both a visual signal and an audio signal.
In an embodiment of the invention, the range signal 64, 62 can include a location of the head-mounted display 10 or the controller 20, or both. The range signal 64, 62 can include a relative location between the head-mounted display 10 and the controller 20 and the relative direction given as a compass direction or indicated with a directional indicator.
In a further embodiment of the present invention, the controller 20 includes a range signal 62 that is initiated by the head-mounted display 10. Alternatively, the head-mounted display 10 includes a range signal 64 that is initiated by the controller 20. The range signal 62, 64 can aid the user in finding one or the other of the head-mounted display apparatus components.
In one embodiment of the present invention, the controller 20 is known to be a temporary controller for the device that is expected to separate from the head-mounted display 10. A temporary controller 20 is part of a separate system and provides control to the head-mounted display 10 only when the head-mounted display 10 is in proximity to the system. Thus, as the head-mounted display 10 is moved from place to place, location-dependent controllers local to the places can provide information to the head-mounted display 10. In this embodiment, the range signal displayed can either be suppressed entirely or displayed is a less intrusive manner. The head-mounted display 10 can record global position satellite (GPS) 72, 74 coordinates and save the coordinates as a location. The head-mounted display 10 can then provide an option to the user to navigate back to the recorded location to return to the controller 20. Referring to
As shown in
In both states, information is projected and viewed by a user, but in the information state, the viewing area 16 is substantially opaque because in the transparent state the viewing area 16 is substantially transparent. Thus, the transparent state enables the user of the head-mounted display 10 to see at least portions of the ambient environment or scene in front of the user. In contrast, the information state enables the user to see projected digital images. The controller 20 of the present invention includes circuitry for producing a control signal for controlling the states of the switchable viewing elements 15. The controller 20 is, for example, a computer, a driver, or a controlling integrated circuit as is known in the computing arts. Circuitry can also be included in the head-mounted display to complement the controller 20 circuitry, particularly to manage the wireless communication and to directly drive the displays or microprojectors 8.
In one embodiment of the present invention, the controller 20 controls each of the switchable viewing elements 15 so that each of switchable viewing elements 15 is semi-transparent. As used herein, a semi-transparent element is an element that transmits some, but not all, of the light incident upon the element. A transparent element transmits substantially all the incident light and an opaque element does not transmit incident light. An opaque element is light-absorbing (e.g. black) or light reflective (e.g. a mirror). A semi-transparent element can transmit various amounts less than all but more than none of the light incident on the element, for example a semi-transparent element can transmit 10%, 30%, 50%, 70%, or 90% of the incident light. In one embodiment of the present invention, the controller 20 controls each of the switchable viewing elements 15 to have any of a plurality of different levels of transparency. For example, the controller 20 can control the switchable viewing elements 15 to be 90%, 50%, or 10% transmissive depending on the control signal provided, for example the strength of an applied electric field to a selected material layer. For the embodiment in which the opaque element is a light-scattering element (e.g. a polymer stabilized liquid crystal layer), light is actually transmitted but the image from the ambient environment is not transmitted because the transmitted light is scattered and as result, the opaque element appears white and the see-through image is not visible.
The invention has been described in detail with particular reference to certain preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention.
Reference is made to commonly assigned U.S. patent application Ser. No. 12/862,994, filed Aug. 25, 2010, entitled Switchable Head-Mounted Display, to John N. Border, et al, the disclosure of which is incorporated herein.
