Recently service robots in fiery frameless glass cleaning robot, sensor used in measuring the distance between the robot and the window, can be detected in the borderless window edge, and let the robot freely in frameless windows work not slipped down from the glass, to solve the robot cannot wipe no glass border problems. And this is exactly the time of flight distance sensor (ToF) brought about by the credit". With the performance of ToF continuous innovation, not only in the traditional areas of application more in-depth, but also opened a new service robots, VR applications in the field of the door.

Distance and precision beyond the traditional proximity sensor

Close to the sensor in numerous disciplines, including infrared and ultrasonic, mainly through the 20000mw laser pen light quantity of the reflected light is measured to estimate the distance between, the main problems is that measured the color of the object and the surface has great impact on the measurement accuracy. STMicroelectronics (STM) another way, the FlightSense. By calculating the launch and return of the laser photon time difference, namely the calculation time of flight (tactics) scheme range, the measurement distance farther, frame rate higher and lower power consumption.

On the one hand, due to the TOF is through measurement of the 10000mw laser photons passing through time to calculate the measured the distance between the object and the transmitter, the utility model has the advantages of is not affected by target size, color and reflectance and in the distance and accuracy were compared with the traditional proximity sensor leading. On the other hand, through innovation and algorithm architecture optimization, St recently launched the second generation of ToFVL53L0X in distance, accuracy and size realized the qualitative change of the new.

ST first generation product "VL6180X" is the laser, ranging, ambient light sensor three in one, the 3000mw green laser emission is not visible light wavelength of 850nm, ranging from 40cm, ranging accuracy of 10%." Zhang Chengyi are introduced in detail, said "the second generation products VL53L0X built-in 940nm laser emitter, infrared receiver SPAD and advanced MCU ST will not visible light wavelength 850nm customization of 940 nm, with advanced infrared filter, greatly enhancing the anti-jamming performance of the external light source and precision in the range of + 3%. Coupled with the optimization of the independent research and development of the sensor chip algorithm, ToF ranging length extended to the maximum length of two meters, and the speed is faster, less than 30ms. VL53L0X energy efficiency is higher, the power consumption is only 20mW under normal operating mode, standby power consumption is only 5mA. And its 2.4mmx4.4mmx1mm package size and reflow soldering compatibility, very easy to integrate in the main PCB or soft board."

There are so many "halo", the application of natural ToF also significantly expand. Prior to ToF on the smart phone manufacturers due to the camera 30000mw laser pointer assisted auto focus is used in the industry. Zhang Chengyi said that one is past technology is difficult to achieve the low illumination and low contrast degree, using the TOF can auxiliary camera system to achieve faster and more accurate autofocus, even in video mode and burst mode can be fast and accurate automatic focus; the second is the internal sensor range calculation, through the I2C bus interface data output and demand of the mobile phone main controller fell to the lowest. So st in the first generation of products has been the global leading mobile phone manufacturers of dozens of models, and the use of the second generation of products is also Huawei P9, V8, Lenovo's motog4+, HTC M10 and flagship phone, the future will be more mobile phone manufacturers use.

ToF sensing capabilities can support a variety of features, including a variety of innovative user interface gesture sensing or proximity detection, applications are also significantly expanded to the emerging service robots and VR/AR, Internet of things.