Apple invents XR Headset Finger Devices that include sensors with submicron resolution that detect the tiniest of movements
Patently Apple has covered a series of Apple patents relating to future HMD Finger Device Accessories over the last few years (01, 02, 03, 04, 05 and 06) and today the US Patent & Trademark Office published yet another one titled "Finger Devices With Self-Mixing Interferometric Proximity Sensors." Apple notes that the Finger Device's proximity sensor may have submicron resolution and may be configured to detect very small movements of the user's finger for accuracy in touching and controlling virtual objects and beyond. While the focus of the finger devices is on using them as an accessory to their future XR Headset, the invention could apply to using finger devices being used to control a display on Macs, an iPad, iPhone, TV and other devices.
In Apple's patent background they note that electronic devices such as computers can be controlled using computer mice and other input accessories. In virtual reality systems, force-feedback gloves can be used to control virtual objects. Yet devices such as these may not be convenient for a user, may be cumbersome or uncomfortable, or may provide inadequate feedback. Apple's latest invention is to provide a superior feedback system for their future XR Headset.
Apple's invention covers a system that may include one or more finger devices that gather input from a user's fingers. The system may include control circuitry that sends control signals to an electronic device based on the input gathered with the finger devices.
A finger device may include one or more proximity sensors that measure a distance to the user's finger. The proximity sensor may be an optical proximity sensor such as a self-mixing interferometric optical proximity sensor having a laser and photodiode.
The proximity sensor may have submicron resolution and may be configured to detect very small movements of the user's finger. The proximity sensor may measure changes in distance between the proximity sensor and a flexible membrane that rests against a side portion of the user's finger.
A self-mixing proximity sensor may have a coherent or partially coherent source of electromagnetic radiation. The source of radiation may, for example, be a coherent light source such as an infrared vertical cavity surface-emitting laser, a quantum cascade laser, or other laser.
The self-mixing proximity sensor may also have a light detector such as a photodiode and/or other electromagnetic-radiation-sensitive element. The photodiode may be stacked with the laser and/or may be an intra-cavity photodiode that is located within the laser cavity. In some arrangements, a single laser driver may drive the lasers of multiple self-mixing proximity sensors using time-multiplexing.
The self-mixing proximity sensor may operate according to a duty cycle. Interpolation and stitching may be used to determine the total displacement of the user's finger including both the on periods and off periods of the self-mixing proximity sensor.
The user may use finger devices in operating a virtual reality or mixed reality device (e.g., head-mounted equipment such as glasses, goggles, a helmet, or other device with a display) and/or in operating other equipment such as desktop computers, laptop computers, tablet computers, a television, an Apple Watch band, included in garments, in material in vehicles and other electronic devices.
During operation, the finger devices may gather user input such as information on interactions between the finger device(s) and the surrounding environment (e.g., interactions between a user's fingers and the environment, including finger motions and other interactions associated with virtual content displayed for a user).
The user input may be used in controlling visual output on the display. Corresponding haptic output may be provided to the user's fingers using the finger devices.
Haptic output may be used, for example, to provide the fingers of a user with a desired texture sensation as a user is touching a real object or as a user is touching a virtual object. Haptic output can also be used to create detents and other haptic effects.
Finger devices can be worn on any or all of a user's fingers (e.g., the index finger, the index finger and thumb, three of a user's fingers on one of the user's hands, some or all fingers on both hands, etc.). To enhance the sensitivity of a user's touch as the user interacts with surrounding objects, finger devices may have inverted U shapes or other configurations that allow the finger devices to be worn over the top and sides of a user's fingertips while leaving the user's finger pads exposed. In other words, the fiber device does not cover the user's finger pad surface. This allows a user to touch objects with the finger pad portions of the user's fingers during use. If desired, finger devices may be worn over knuckles on a user's finger, between knuckles, and/or on other portions of a user's finger. The use of finger devices on a user's fingertips is sometimes described herein as an example.
Apple's patent FIG. 1 is a schematic diagram of an illustrative system with a finger device; FIG. 2 is a top view of an illustrative finger of a user on which a finger device has been placed on; FIG. 3 is a cross-sectional side view of an illustrative finger device on the finger of a user.
Apple's patent FIG. 6A above is a cross-sectional side view of an illustrative self-mixing interferometric proximity sensor that includes a flexible membrane attached to rigid sidewalls;
Apple's patent FIG. 6B above is a cross-sectional side view of an illustrative self-mixing interferometric proximity sensor that includes a continuous flexible membrane.
Apple's patent FIG. 6C is a cross-sectional side view of an illustrative self-mixing interferometric proximity sensor that includes a rigid structure attached to flexible sidewalls.
Apple's patent FIG. 6D is a cross-sectional side view of an illustrative self-mixing interferometric proximity sensor that includes a semi-rigid, cantilever structure.
Apple's patent FIG. 4A above is a cross-sectional side view of an illustrative finger device with a self-mixing interferometric proximity sensor on the side of the finger of a user.
Apple's patent FIG. 9 below is a schematic diagram of illustrative sensing circuitry that may be used to determine displacement using the self-mixing interferometric proximity sensor.
Apple's patent FIG. 11 above is a series of graphs showing how an illustrative self-mixing interferometric proximity sensor may operate with a duty cycle and use interpolation and stitching to calculate a total displacement; and FIG. 13 is a schematic diagram showing how a single laser driver may operate multiple self-mixing interferometric proximity sensors using time-multiplexing.
For more details, review Apple's patent application #US 20230073039 A1.
- Mengshu Huang: Sensing HW Design
- Yuhao (Roy) Pan: Product Design Engineer
- Mehmet Mutlu: Engineering Manager, Display Optics Design (Now at Meta)
- Fatih Cihan: Optical Sensing Hardware Engineer (Now at Google)