Bosch Sensortec has produced prototype smartglasses to demonstrate suitability for applications in head-up navigation, for messaging and notifications instead of smartwatch and for directed activities including to-do lists, shopping lists and other check lists.
The system level product is based on the BLM050 microscanner that was introduced in 2017 (see MEMS scanner projects Bosch Sensortec into displays, user interfaces).
The BLM050 is a generic two-MEMS optical scanner for RGB visible light and IR laser projection which is inherently in focus. The component can be used for the projection of images and the creation of a projected virtual user interface and Bosch has developed its geometry perspective scaling to allow images to appear correct when under oblique projection.
Bosch Sensortec is now offering the MEMS scanner along with laser, and beam shaper, control ASIC and Bluetooth communications on a PCB that can fit into the arm of smartglasses as part number BML500P. The unit weighs less than 10g and is compatible with curved lenses of prescription glasses.
The unit also includes the BHI260 smart accelerometer including 32bit MCU, the BMP388 barometric pressure sensor, and the BMM150 magnetometer. These sensors enable user interface features such as multi-tap functions on the frame to improve convenience while operating the glasses.
This is also an example of the platform approach to MEMS component selling previously advocated by Bosch Sensortec CEO Stefan Finkbeiner (see MEMS platforms are way to go, says Bosch’s Finkbeiner).
The display is laser-based with the beam of light scanned on to a transparent holographic element (HOE) embedded in the glasses and then on to wearers retina. The content is invisible to the outside world and is private to the user.
Bosch Sensortec can also provide a turnkey light-drive with holographic lens support for companies with less engineering resource or requiring faster time to market. The company claims the images are bright even in direct sunlight.
Next: Safer driving
“The Smartglasses Light Drive system is the smallest and lightest product on the market today and is, therefore, able to turn almost any regular spectacles into smartglasses,” said Finkbeiner in a statement. “By eliminating distracting phone usage, smartglasses can help improve driving safety and reduce the impulse of users to constantly check their mobile devices for notifications or messages.”
It may be remembered that one problem with Google Glass was that it ran so hot, particularly performing functions such as video conferencing, that it could burn the wearer if used for prolonged periods. This was partly because Glass was an ambitious demonstrator made with non-optimized components. Ultimately Glass failed for reasons of social acceptability.
The BML500P consumes considerably less power than Google Glass and is being aimed at simple display of text- and icon-based information. The claimed 14 hours operation from a 350mAh battery implies an average current draw of 25mA. With a typical voltage scheme this suggest a power consumption of about 80mW.
Bosch Sensortec claims it has also addressed problems with older competitor displays of a haze or rainbow that is visible when the system is switched off. Bosch’s holographic optical element removes these distracting internal reflections.
The BML500P measures 45mm to 75mm by 5mm to 10mm by 8mm. The final configuration is up to customers but should be more easily contained within glasses arms and able to make smartglasses less noticeable and more socially acceptable.
The Bosch Smartglasses products will be available in 2021 to high-volume manufacturers and Bosch said it will also be able to provide software and services for technical integration to complement the ramp-up to mass production.
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