This application relates to integration of capacitive sensing with head-mounted display (HMD) technology to create a more reliable and more intuitive user control interface.
The consumer electronics marketplace has witnessed increasing replacement of traditional switches (pushbutton, toggle, etc.) with capacitive sense technology. One of the most recognized implementations of this technology are gesture based touch-screens such as the Apple iPhone's unlock feature (Apple™ and iPhone™ are trademarks of Apple, Inc. of Cupertino, Calif.). The user simply pushes and slides their finger across the bottom of the screen to unlock the device. That motion is intuitive to figure out. Additionally, the action of doing so is such that it cannot be easily done inadvertently if the device is in one's pocket.
Another example of a capacitive sense toggle switch can be seen on the Sony Playstation 3 (PS3) console system. (Sony™, Playstation™, and PS3™ are trademarks of Sony Corporation of Tokyo, Japan). The on/off power switch and the eject button of the PS3 are both cap sense buttons with logos imprinted on the plastic so the user knows its function.
Capacitive sense technology can also be expanded to proximity sensing. To utilize the iPhone as an example once again, the iPhone senses when it is in close proximity to the users' face during a call. It shuts off the backlight to save power and disables operation off all the buttons so they are not accidentally pressed.
Head-mounted displays (HMDs) and video eyewear provide large format pictures in a small form factor. The HMD is a portable media device and as such the unit is designed to be small and lightweight. A typical HMD connects to a battery pack and another portable device that serves as the video source. The controls for the HMD are normally located on the battery pack itself. The controls can also be placed inline with the cable on a small push-button adapter that will lie somewhere between the person's head (HMD location) and the person's waist (battery pack location).
Another style of HMD design is the stand-alone configuration. In this type there is no cable and no battery pack. Instead, the batteries and controls are located inside or on the HMD itself. This style of HMD typically has push-buttons and slide switches located on the arms. However, the user must memorize the button locations and functions prior to putting on the eyewear or figure it out through trial and error. It is generally not an intuitive design.
As mentioned earlier, current HMD designs that offer controls on the HMD itself typically utilize push-button switches and lack an intuitive nature. Another major consequence of the prior designs is that to actuate the switch requires a significant amount of pressure. This can easily cause the HMD to move and thus disrupt the user's viewing of a video. On the other hand, capacitive sense arrays implemented as discussed herein, require little or no contact depending on the sensitivity of the electrode. The user can lightly press their finger to the plastics to control it and continue to watch the video unhindered.
The utilization of capacitive touch technology on an HMD greatly improves their design by making user control inputs more intuitive.
The capacitive sensor or sensor arrays can be placed on the arms of the HMD in a slider configuration for volume control. The sensed input can be integrated with on screen display to show the volume level, such as while the capacitive array is being pressed. The same concept can be used to control the display brightness, mode, etc.
The relative location of either display can be electronically adjusted to adjust the stereoscopic convergence or correct for a person's IPD (interpupillary distance) preference, such as by touching and sliding a finger on a capacitive array located on the front of the unit. Such an input moves the relative location of the two images electronically.
HMD power can also be controlled by a capacitive sensor arranged in proximity to the user's face. A low power standby mode is entered when the user's face is not present, and a power off mode is entered if the HMD is not used for some period of time. These features save battery life.
To further increase the intuitive nature of capacitive sensor control, their operation can be integrated with an on-screen display. For example, a volume level indication can be displayed as soon as the array is pressed, with adjustment possible after holding the finger on the array for a short period of time. This is desirable so that the user can be sure they are adjusting the proper button. Also, this time delay reduces the risk of inadvertent adjustments being made simply by grabbing the HMD.
Capacitive touch sensors also make button placement much more flexible because the electrodes can be positioned against the outer edge of the plastics when patterned on a flexible board. Therefore the volume control can be made closer to the ear, the brightness control a slider near the display. The designer no longer needs the same rigidity and size that would be required to hold physical moving buttons.
One of the major design metrics for HMDs is the weight of the unit. Using capacitive sense arrays in place of buttons is a definite advantage. The capacitive sense electrodes can be patterned onto a flex circuit which is very light weight. There is nothing mechanical about the array so there is much less worry about the device breaking from improper use or wear-and-tear over time like a normal switch.
Furthermore, interpupillary distance (IPD) is the distance between the centers of one's pupil to the other pupil. This varies a good amount from person to person, with the average adult male having an IPD of 63.5 mm. Typical adjustment methods are mechanical, where the two displays are physically moved by the user. Although this type of control works, it adds weight and complexity to the system adding another mechanism that can break.
With the integration of capacitive sense to a binocular HMD, it is possible to handle IPD adjustment electronically. The user can adjust the IPD to fit his personal preference, providing that there are some extra unused pixels horizontally on either side of the displays to allow for moving the image within it. Providing control to do this by sliding a finger near the display is much more intuitive than having to navigate through a menu system to accomplish the same thing. A pinch and spread motion between the two eyes is also an intuitive way to adjust IPD or even used to zoom in and out of the image is the display processing can handle it. The applications of such sensor arrays to control aspects of the multimedia presented on the HMD are really quite extensive.
At the HMD, it is also possible to utilize capacitive sensor as a proximity sensor. In portable electronics, battery life is extremely important. There is no need to be running the display or backlights if the user has taken the eyewear off or flipped it up into a stowed position. A capacitive sense electrode that is configured to be very sensitive is able to detect the presence of the user's face. This information can be used to enter standby mode if the viewer takes the eyewear off. Eyewear that is designed to flip up and stow without being removed from the user's head can also utilize this proximity sensor to enter standby. To do so the HMD should be mechanically designed to have a ground shield between the capacitive sensor and the user's head only when in the stowed position. The sensor in this design will have similar readings to that of being totally removed. After a prolonged period of standby time the software could shut the entire system off.
The proximity sensor idea can be expanded even further if the device is integrated with an external video player. Once the system enters standby, the HMD can send a message to the player issuing a pause command so that they can pick up right where they left off.
Many of these capacitive sense ideas mentioned in the context of HMDs above can be moved (physically) to an external battery pack electronics and not lose any of the added intuitive functionality. In fact, the battery pack allows for a larger rectangular area to work with when designing the electrodes. A push and hold power switch could replace a common slide switch.
The foregoing will be apparent from the following more particular description of example embodiments of the invention, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views.
The drawings are not necessarily to scale, emphasis instead being placed upon illustrating embodiments of the present invention.
A description of example embodiments of the invention follows.
Of particular interest to the present embodiment is the use of one or more capacitive touch sensors 200, 210, 220.
A first capacitive sensor 200 is embodied as a capacitive sensor array placed in the bridge area 170. Sensor array 200 is used for adjusting interpupillary distance (IPD) between the two presented images.
A second sensor array 210 is located on the left arm 150-L and is used such as to provide a volume control input.
A third sensor 220 is located in a portion of the HMD 100 that located near the user's 105 face when the HMD is being used.
Turning attention to
Visual feedback can be provided to the user in one of the displays 160-L and/or 160-R, such as by displaying a volume sliding bar 182. The volume bar 182 can be temporarily shown and/or shown only when the user presses their finger 107 against the sensor 210.
When the arms 150 are placed in the lower position (such as shown in
In the preferred embodiment, the HMD 100 uses an Advanced Reduced instruction set computer (RISC) Machine (ARM)/Digital Signal Processor (DSP) 512 (which may be an Open Multimedia Application Platform (OMAP) 3500 series processor, available from Texas Instruments of Dallas, Tex.), memory 514, Bluetooth interface 516 which may be provided by a Class 2 Bluetooth interface available from Cambridge Silicon Radio (CSR) of Cambridge, England), display driver 519 (which may, for example, be an SSD1508 or other suitable display driver available from Kopin Corporation of Westborough, Mass.), video level shifter circuits 520, a power supply 522 supported by a battery 524, universal receiver transmitters (UART) 526 (such as may be used for debugging) and memory 515. A Secure Digital (SD), eXtreme Digital (xD), USB SD (uSD) memory 517 or other similar interfaces may be used to store application programs, kernel directives, or configuration data, and/or connect to devices such as a digital camera. A number of input device 530 may be associated with the device (e.g., switch 1/switch 2/switch 3 and reset inputs), camera 546, Hall effect sensors 547, MIM diodes 548, accelerometers 549, track pads and scroll wheels, and an LED output 532 (led 1). A pair of VGA or better quality microdisplay elements 160-L, 160-R and audio input and output device(s), which may include microphone input 562 and stereo outputs 564, are also provided.
A video signal to be displayed to the user may be received over a Bluetooth™ wireless communication link 235 established using Serial Port Profile (SPP), as opposed to using any of the “advanced” Bluetooth modes, which provides greater throughput higher than the higher layer protocols imposed by such advanced modes that have been found not to be needed in this application. In the Bluetooth™ radio 516, a video signal received over the Bluetooth™ connection is sent over the USB connection 518 to the processor 512. One design consideration is to optimize data packet format, given known data buffer sizes. Internal to the Bluetooth™ radio 516 is a packet buffer default size of 1000 bytes. This may be modified to force streaming video signals to use only about a 990 byte buffer size. The processor 512 may expect the received video content to be encoded with the H.264 (Motion Picture Experts Group (MPEG)-4 part 10) formatting, using the so-called baseline profile or better.
In a preferred embodiment, the processor 512 may use a multi-tasking embedded operating system. The processor 512 operates on the received video signal as follows. An MPEG format container file (e.g., a .MP4 file) is made available. In one preferred embodiment, this may be a proprietary file format, although the specific details of the input .MP4 file format chosen are not important here, as long as the processor 512 is programmed to correctly process it. The processor 512 then opens a communication port to the host computing device and receives the file over the USB interface 518 from the Bluetooth™ radio 516.
An MP4 decoder in the processor 512 strips the file into respective audio and video streams. More particularly, the processor 512 decodes the input file H.264 compressed digital video signal into a YCbCr baseband component video signal. The processor 512 may also divide the associated compressed audio (formatted as an Advanced Audio Coding (AAC) format signal) into baseband stereo audio.
The processor 512 may output video in any suitable format such as an 8 bit, International Telecommunication Union Radiocommunication Sector (ITU-R) Recommendation BT. 656 or Society of Motion Picture and Television Engineers (SMPTE) 293M 16 bit YUV progressive scan signals with separate sync signals, to the display driver 519. The decompressed video signal is forwarded over an internal ARM bus of the processor 512. The ARM bus then sends the content directly to the display driver 519 via the SMPTE 293M interface. The Intelligent Interface Controller (I2C) interface 547 is used to configure the microdisplay elements 160. The processor 512 also outputs the baseband audio to the audio output Compression/Decompression Module (CODEC) 560. It may take mono or stereo audio input and produce suitable stereo output signals.
Also shown here are the connections of the capacitive sensors 200, 210, 220 to the processor 512. These sensors, as explained above, are used to control a volume for the audio output 564, aspects of the video presentation aspects such as IPD, stereoscopic convergence, or brightness, or control over the operation of the HMD in response to proximity of the user's face. These inputs are then used by the audio circuits 560 and/or display drivers 519 and/or power supply 522 for corresponding control.
In this example embodiment, there are a total of six digital scalers 1130 used (one each for the R, G, B channels for each of the left and right displays), since interpolation of each color channel is preferably done separately from the other channels. Digital scalers 1130 “make up” the difference in horizontal resolution between the higher resolution display and now lower resolution input signal fed to each eye. Digital scalers 1130 can be implemented as a simple repetition of pixels in the horizontal resolution of the input video stream and the two displays 160. In a case where the scale factor is a simple integer reciprocal (such as 2:1), scaling 1130 can be implemented as a simple repetition of pixels. However, in other cases, where the scale factor is not an integer reciprocal, more complicated scaling techniques such as linear interpolation may be used. In either case, scalers 1130 are preferably implemented in the digital domain, such as by the OMAP 512, which may achieve better results than possible with the prior art methods of resampling an analog signal.
Some example considerations for the digital scalers 1130 include the following:
After undergoing any necessary scaling by scalers 1130-L, 1130-R, the output streams pass to the left and right video display drivers 1140-L and 1140-R. Each display driver 1140 typically includes one or more D/A converters and one or more video amplifiers.
In an embodiment, the system may implement a 3D viewing mode that can be selectively switched to a 2D mode by changing the scaling factor in the digital scalers 1130. That is, instead of applying interpolation, the same buffer output, without scaling, is sent to each display 160-L, 160-R.
Soft IPD and Convergence Adjust
In another implementation, the HMD 100 may be adapted to provide soft Inter-Pupilliary Distance (IPD) or convergence adjustments.
In particular, it is not uncommon for the available resolution of the physical displays 160 to exceed that of the presented image in the input video stream. For example “wide VGA” displays such as the Kopin CyberDisplay® WVGA mentioned above may have up to 864 active columns, but are often used to display content with horizontal resolutions of only 854, 768, 720, or 640 pixels. In these situations, the drive electronics 100 will typically center the active image horizontally and drive the inactive “side” pixel columns to black. However, by varying the size of the resulting left and right black borders (refer back to
Because the HMD provides independent video signals to the two displays, it is possible to control the border sizes on left and right displays independently. For example, moving the left image to the right and the right image to the left would change the stereoscopic convergence and make the image appear closer to the user. In this way, the convergence of the stereoscopic images may be adjusted for optimal viewing via electronic controls, without requiring mechanical adjustments to the display or lens position. Such adjustments may be desirable to accommodate variations in the video source material or in the viewer's Interpupilliary Distance (IPD). This can then affect the 3D depth perceived by the viewer.
In such an embodiment, as shown in
It should be understood that the stereoscopic convergence or IPD adjustment need not depend on a particular scale factor, and indeed can be applied to other 2D or 3D video eyewear systems such as the systems that do not apply scale factors at all. The horizontal shift may be performed before or after scalers 1130-L, 1130-R such as by changing the address from which the digital scalers 1130-L, 1130-R read from the line buffer memory 1120 (as shown in
It should now be appreciated that the specific physical form of the HMD 100 in
Likewise, sensors 3200-L and 3200-R may be embedded in a plastic external eyepiece of another type of eyewear device as shown in
Many of the above ideas may also apply to capacitive touch sensors located on other portions of different types of HMDs, such as those that may have an external battery pack. Since the battery pack presents a large surface area it is possible to implement the touch sensors there.
The teachings of all patents, published applications and references cited herein are incorporated by reference in their entirety.
While this invention has been particularly shown and described with references to example embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention encompassed by the appended claims.
This application claims the benefit of U.S. Provisional Application No. 61/301,865, filed on Feb. 5, 2010. The entire teachings of the above application are incorporated herein by reference.
Number | Name | Date | Kind |
---|---|---|---|
3936869 | Jirka | Feb 1976 | A |
5129716 | Holakovszky et al. | Jul 1992 | A |
5990793 | Bieback | Nov 1999 | A |
6108197 | Janik | Aug 2000 | A |
6124976 | Miyazaki | Sep 2000 | A |
6204974 | Spitzer | Mar 2001 | B1 |
6325507 | Jannard et al. | Dec 2001 | B1 |
6349001 | Spitzer | Feb 2002 | B1 |
6798391 | Peterson, III | Sep 2004 | B2 |
6853293 | Swartz et al. | Feb 2005 | B2 |
6900777 | Hebert et al. | May 2005 | B1 |
6922184 | Lawrence et al. | Jul 2005 | B2 |
6956614 | Quintana et al. | Oct 2005 | B1 |
6966647 | Jannard et al. | Nov 2005 | B2 |
7004582 | Jannard et al. | Feb 2006 | B2 |
7082393 | Lahr | Jul 2006 | B2 |
7147324 | Jannard et al. | Dec 2006 | B2 |
7150526 | Jannard et al. | Dec 2006 | B2 |
7213917 | Jannard et al. | May 2007 | B2 |
7216973 | Jannard et al. | May 2007 | B2 |
7219994 | Jannard et al. | May 2007 | B2 |
7249846 | Grand et al. | Jul 2007 | B2 |
7278734 | Jannard et al. | Oct 2007 | B2 |
7331666 | Swab et al. | Feb 2008 | B2 |
7445332 | Jannard et al. | Nov 2008 | B2 |
7452073 | Jannard et al. | Nov 2008 | B2 |
7461936 | Jannard | Dec 2008 | B2 |
7494216 | Jannard et al. | Feb 2009 | B2 |
7512414 | Jannard et al. | Mar 2009 | B2 |
7682018 | Jannard | Mar 2010 | B2 |
7740353 | Jannard | Jun 2010 | B2 |
7744213 | Jannard et al. | Jun 2010 | B2 |
7753520 | Fuziak, Jr. | Jul 2010 | B2 |
7806525 | Howell et al. | Oct 2010 | B2 |
7918556 | Lewis | Apr 2011 | B2 |
7966189 | Le et al. | Jun 2011 | B2 |
7967433 | Jannard et al. | Jun 2011 | B2 |
7969383 | Eberl et al. | Jun 2011 | B2 |
7969657 | Cakmakci et al. | Jun 2011 | B2 |
7988283 | Jannard | Aug 2011 | B2 |
7997723 | Picnimaa et al. | Aug 2011 | B2 |
8020989 | Jannard et al. | Sep 2011 | B2 |
8025398 | Jannard | Sep 2011 | B2 |
8072393 | Riechel | Dec 2011 | B2 |
8092011 | Sugihara et al. | Jan 2012 | B2 |
8098439 | Amitai et al. | Jan 2012 | B2 |
8123352 | Matsumoto et al. | Feb 2012 | B2 |
8140197 | Lapidot et al. | Mar 2012 | B2 |
8144129 | Hotelling et al. | Mar 2012 | B2 |
8212859 | Tang et al. | Jul 2012 | B2 |
20020015008 | Kishida et al. | Feb 2002 | A1 |
20020094845 | Inasaka | Jul 2002 | A1 |
20030068057 | Miller et al. | Apr 2003 | A1 |
20040174605 | Olsson | Sep 2004 | A1 |
20050168438 | Casebolt et al. | Aug 2005 | A1 |
20050264527 | Lin | Dec 2005 | A1 |
20060007176 | Shen | Jan 2006 | A1 |
20060132382 | Jannard | Jun 2006 | A1 |
20070052672 | Ritter et al. | Mar 2007 | A1 |
20080088529 | Tang | Apr 2008 | A1 |
20080198324 | Fuziak | Aug 2008 | A1 |
20090128448 | Riechel | May 2009 | A1 |
20090153389 | Kerr et al. | Jun 2009 | A1 |
20090154719 | Wulff et al. | Jun 2009 | A1 |
20090174685 | Langella | Jul 2009 | A1 |
20090180195 | Cakmakci et al. | Jul 2009 | A1 |
20100020229 | Hershey et al. | Jan 2010 | A1 |
20100033830 | Yung | Feb 2010 | A1 |
20100053069 | Tricoukes et al. | Mar 2010 | A1 |
20100121480 | Stelzer et al. | May 2010 | A1 |
20100149073 | Chaum et al. | Jun 2010 | A1 |
20100171680 | Lapidot et al. | Jul 2010 | A1 |
20100238184 | Janicki | Sep 2010 | A1 |
20100271587 | Pavlopoulos | Oct 2010 | A1 |
20100277563 | Gupta et al. | Nov 2010 | A1 |
20100283711 | Sadler | Nov 2010 | A1 |
20100289817 | Meier et al. | Nov 2010 | A1 |
20110001699 | Jacobsen et al. | Jan 2011 | A1 |
20110089207 | Tricoukes et al. | Apr 2011 | A1 |
20110090135 | Tricoukes et al. | Apr 2011 | A1 |
20110214082 | Osterhout et al. | Sep 2011 | A1 |
20110221669 | Shams et al. | Sep 2011 | A1 |
20110221671 | King, III et al. | Sep 2011 | A1 |
20110227812 | Haddick et al. | Sep 2011 | A1 |
20110227813 | Haddick et al. | Sep 2011 | A1 |
20110254698 | Eberl et al. | Oct 2011 | A1 |
20110255050 | Jannard et al. | Oct 2011 | A1 |
20110273662 | Hwang et al. | Nov 2011 | A1 |
20120013843 | Jannard | Jan 2012 | A1 |
20120026071 | Hamdani et al. | Feb 2012 | A1 |
20120056846 | Zaliva | Mar 2012 | A1 |
20120062445 | Haddick et al. | Mar 2012 | A1 |
20120088245 | Rotter et al. | Apr 2012 | A1 |
20120105740 | Jannard et al. | May 2012 | A1 |
20120114131 | Tricoukes et al. | May 2012 | A1 |
20120188245 | Hyatt | Jul 2012 | A1 |
Number | Date | Country |
---|---|---|
WO 9521408 | Aug 1995 | WO |
WO 9523994 | Sep 1995 | WO |
WO 0079327 | Dec 2000 | WO |
WO 2009076016 | Jun 2009 | WO |
WO 2011051660 | May 2011 | WO |
WO 2012040386 | Mar 2012 | WO |
Entry |
---|
Notification of Transmittal of the International Search Report and the Written Opinion, including copies of International Search Report and Written Opinion; International Application No. PCT/US11/23898, Date of Mailing Mar. 30, 2011. |
International Preliminary Report on Patentability and Written Opinion, PCT/US2011/023898, date of mailing Aug. 16, 2012, 6 pages. |
Number | Date | Country | |
---|---|---|---|
20110194029 A1 | Aug 2011 | US |
Number | Date | Country | |
---|---|---|---|
61301865 | Feb 2010 | US |