3D Sensors Add Depth to Surveillance and Gaming
More 3D-enabled consumer devices, coupled with increased sensing in gaming and sophisticated security and surveillance systems, show the 3D sensors market cleared for take-off.
3D sensors, i.e. image sensors, position sensors, accelerometers and acoustic sensors, are seeing a rise in demand, as they are used in consumer and wearable devices, security and surveillance systems, automotive, and industrial applications. Market size estimates vary widely, from $3.92 billion in 2022 (Global 3D Sensor Market . . . 2017-2022 – Mordor Intelligence) to $12 billion by 2025 (Global 3D Sensors Market Analyst & Trends Industry Forecast to 2025 – Reportlinker). However all report significant Compound Annual Growth Rates (CAGR) of between 17 percent (Reportlinker) to 26.5 per cent (3D Sensors Market . . Global Trends & Forecast to 2022 – Markets & Markets).
Of the technologies used in 3D sensors, stereo vision, structured light, ultrasound, and Time of Flight (ToF), it is ToF that is expected to control a major share of the total market. ToF sensing sends a light or acoustic signal to a target and determines when the reflected signal is received from the target, to ascertain movement direction and speed. It is not the light reflected back from the object, which can be altered by color and surface, that is measured, but rather the time the light takes to travel to the nearest object and reflect back to the sensor. Hence its name; it measures the time of flight for the signal.
Time of Flight Technology
ToF is also expected to have the fastest growth of all the 3D sensor technologies, as buyers and specifiers exploit its higher frame rate, compared with other sensor technologies. The compact form factor is also finding favor with developers in healthcare, aerospace, and defense applications.
The imaging and proximity sensing technology can be used for remote control and auto-focus assist in communication and consumer devices. For home appliances, it adds convenience with gesture control. Robot cleaners and drinking machines employ the technology to signal when objects are present, as do toys. Gesture control also has an increasing presence in vehicles for console control of the on-board computer. For the industrial sector it adds safety and security, with proximity and light detection for objects and personnel as well as for door control and robotics.
In the consumer market, Apple is using a customized ToF sensor from STMicroelectronics in the iPhone 7 Plus. It is used as a proximity sensor and the camera’s range finder. The customized ToF sensor is in an optical Land Grid Array (LGA) and is smaller than any other proximity sensor offered by STMicroelectronics, measuring 2.8 x 2.4mm. The sensor is based on STMicroelectronics’ FlightSense technology, using a Vertical-Cavity Surface-Emitting Laser (VECSEL) and a collector element based on the company’s Single Photon Avalanche Diode (SPAD).
The VL6180X is STMicroelectronics’ most recent proximity sensor, gesture and Ambient Light Sensing (ALS) module, based on FlightSense technology (Figure 1).
The three-in-one optical module is for low-power operation and measures an absolute range of up to 100mm. The host system can use the distance and signal level for gesture recognition functionality in smartphones and devices with touchscreens, as well as tablet and laptop computers and gaming devices and also domestic appliances and industrial equipment. The company also offers the VL53L0X ToF laser-ranging module (Figure 2) which is housed in a small package, measuring just 4.4 x 2.4 x 1.0mm. It uses STMicroelectronics’s second generation of FlightSense technology.
Like the VL6180X, it is also based on a SPAD array and combines a 940nm VCSEL emitter and internal physical infrared (IR) filters to provide a longer range; measuring absolute distances of up to 2m. It operates in high IR ambient light levels and has embedded optical cross-talk compensation to expand the glass cover options available for use.
Introducing Augmented Reality
German chip manufacturer Infineon also uses ToF technology in its REAL3 image sensor chip family. At CES 2017, it announced that a REAL3-based 3D ToF camera is used in the ASUS Zenfone AR (Figure 3).
The image sensor technology used in the camera is scalable and counters the effects of texture and surfaces with the patented Suppression of Background Illumination (SBI) circuitry in every pixel, as well as the use of active modulated IR light. The monocular architecture means that shutter speed is fast, with a low latency of one to four milliseconds (typical). There is also no need for mechanical alignment or angle correction and no special requirements are needed for mechanical stability when using the ToF camera.
Is it just a gimmick, or can AR enhance the user experience? It obviously enhances any gaming apps on the smartphone, and can also be used in consumer applications, such as projecting a virtual object into the real-world environment, for example, projecting a chair into the room setting before making that online purchase. AR can also be used in industrial settings, to maintain equipment.
The Zenfone AR is small, with a height of less than 9.0mm. The camera module is just 5.9mm and draws less than 150mW during operation to meet the power consumption needs of the smartphone, which is powered by a 3,300mAh battery.
For real future-thinking for 3D sensing research, I would hand a 3D sensor-enabled device to a seven-year-old and a 15-year old and see what they do with it. I predict the possibilities are endless.
Caroline Hayes has been a journalist covering the electronics sector for more than 20 years. She has worked on several European titles, reporting on a variety of industries, including communications, broadcast and automotive.