The new sensor is able to measure in a range more than five times larger than that possible with 3D sensors using the conventional indirect ToF method. This will help improve the operability and safety of autonomous drones and robot carriers, which are equipped with sensors that allow them to avoid obstacles. The hybrid ToF sensor also has a unique function to remove ambient light, making it the world’s first CMOS image sensor capable of measuring distances up to 20 meters in conditions with an illumination of 100,000 lux, equivalent to daylight in mid-summer.
Details of this new type of ToF sensor technology were presented at June 15 from Toppan, Brookman Technology and Shizuoka University at the IEEE Symposium on VLSI Technologies and Circuits (VLSI Symposium), an international conference on semiconductor technology held in 2022. Honolulu, Hawaiifrom From 13 to 17 June from the Institute of Electrical and Electronics Engineers.
The market for 3D sensors is expected to expand as smartphones and game consoles become more sophisticated and the use of stand-alone robots in the industry is growing. There are several different types of 3D sensors based on the different principles used to detect distances. ToF sensors estimate the distance to an object by measuring the time it takes for the emitted light to reflect back. Against the background of advances in technological development in recent years, the use of ToF sensors for smartphones and other devices is increasing due to their compact form factor and low power consumption.
Autonomous robots and drones must have an environmental mapping function that allows them to detect obstacles tens of meters in front and determine their own position from video images. However, the widespread use of 3D sensors using the conventional indirect ToF method is limited due to insufficient tolerance to ambient light when used outdoors.
With Brookman Technology already on board as a subsidiary, Toppan was able to use the strengths of both companies to stimulate the development of a new type of 3D sensor. This led to the development of hybrid ToF technology based on the refinement of Brookman Technology’s unique “short-pulse modulation”. a method allowing the measurement of long distances, exceptional tolerance to ambient light, high-speed images and the simultaneous use of multiple cameras.
“Together with Brookman Technology, we hope that these new sensors contribute to greater safety and convenience by acting as ‘3D sensor eyes’ that expand the capabilities of stand-alone robots and industrial devices,” they said. Tatsuo Noguchi, Head of ToF’s ToF Business Development Center. Toppan will stimulate the further development of cameras with range sensors using the new ToF technology, with a plan to offer models for testing from December this year and launch sales in the fall of 2023.
Features of the new ToF sensor
Measurement of distances up to 30 meters
Use on the hybrid ToF method makes it possible to measure distances up to 30 meters, about five times more than conventional models.
Noise suppression function to facilitate outdoor measurements in mid-summer conditions
Each pixel is equipped with a function to remove external light components. This removes noise from ambient light and makes accurate measurements possible even when the illuminance is in the range of 100,000 lux, equivalent to daylight in mid-summer.
High-speed display at 120 frames per second
Distances can be measured without blur, which can cause errors, as the measurement and elimination of ambient noise is done in one frame. This allows you to capture a maximum of 120 images with a range per second, approximately four times the capabilities of existing models.
Simultaneous operation of up to 256 cameras
Unique control technology makes it possible to cancel the signals emitted by other cameras by treating them as ambient light. This means that up to 256 cameras can be operated simultaneously without interference between cameras.
About Brookman Technology
Brookman Technology, Inc. starts in Hamamatsu, Japan in 2006 as Brookman Laboratory, Inc., by a leading expert on CMOS image sensors, Dr. Shoji Kawahito, a professor of electrical engineering at Shizuoka University. Since then, Brookman Technology has been working on multiple forms of CMOS analog and mixed signal IC design, specializing in the design of advanced CMOS image sensors for a wide range of applications. The company became a subsidiary of Toppan in March 2021 by acquiring 94.6% of its shares.
Created in Tokyo in 1900, Toppan was a leading and diversified global provider committed to providing sustainable, integrated solutions in areas including printing, communications, security, packaging, decoration materials, electronics and digital transformation. Toppan’s global team of more than 50,000 employees offers optimal solutions provided by industry-leading expertise and technology to meet the diverse challenges of each business sector and society and contribute to shared goals of sustainability.
For more information, visit https://www.toppan.com/en/ or follow Toppan on LinkedIn https://www.linkedin.com/company/toppan/.
1. The hybrid ToF method, proposed by Prof. Shoji Kawahito of Shizuoka University, is a new sensor technology based on the indirect ToF method for measuring distance by phase difference and combining it with a direct ToF methodology for measuring time difference. Since the travel time of light is calculated by combining multiple short-lived windows using so-called “multiple window technology”, the tolerance of the hybrid method to ambient noise, which can be problematic when performing outdoor detection, is more better than that of the conventional indirect ToF method.
2. As a ToF sensor with a conventional CMOS pixel structure of the image sensor that does not use an avalanche photodiode. Toppan study based on prior art documents and existing product catalogs (June 2022).
3. Unlike “continuous wave modulation”, which emits continuous waves of light, “short pulse modulation” is a method of measuring distance by emitting pulses of light of extremely short duration.