Sony Semiconductor Solutions Unveils Groundbreaking SPAD Depth Sensor for Automotive LiDAR
In an exciting development for the automotive industry, Sony Semiconductor Solutions Corporation (SSS) has announced the forthcoming release of its IMX479 SPAD depth sensor. This innovative sensor, designed for automotive Light Detection and Ranging (LiDAR) systems, promises to deliver unprecedented levels of high-resolution and high-speed performance. It aims to enhance the capabilities of Advanced Driver Assistance Systems (ADAS) and automate driving technologies, thereby contributing to safer and more reliable transportation.
Overview of the IMX479 Sensor
The IMX479 is a stacked, direct Time of Flight (dToF) sensor that leverages Single Photon Avalanche Diode (SPAD) technology. SPAD is a highly sensitive photon detector capable of counting single photons, which makes it ideal for LiDAR applications. The sensor features a dToF pixel unit comprised of a 3×3 array of SPAD pixels, which improves measurement accuracy through line scan methodologies. This sophisticated design allows the sensor to achieve a frame rate of up to 20 frames per second (fps), setting a new benchmark for high-resolution SPAD sensors with 520 dToF pixels.
How the Sensor Works
LiDAR technology is crucial for detecting and recognizing road conditions, as well as identifying the position and shape of objects such as vehicles and pedestrians. The IMX479 sensor utilizes the dToF measurement method, which calculates the distance to an object by measuring the time it takes for light to travel from the source, reflect off the object, and return to the sensor. This method is particularly effective for automotive applications, where precision is paramount.
Technological Innovations
The IMX479 incorporates several proprietary technologies developed by SSS. Among these is the back-side illuminated, stacked structure, a design that enhances light sensitivity and efficiency. Additionally, the sensor employs Cu-Cu (copper-copper) connections, which are used to stack pixel chips with logic chips. This allows for electrical continuity and a compact design, resulting in improved performance and productivity.
Furthermore, the integration of newly developed distance measurement circuits directly onto the sensor chip allows for high-speed data processing. This, combined with the sensor’s small pixel size of 10 micrometers squared, enables it to offer a high resolution of 520 dToF pixels.
Key Features and Benefits
- High Frame Rate and Resolution: The sensor can achieve a frame rate of up to 20 fps, which is the fastest for a 520 dToF pixel SPAD depth sensor. This high-speed performance is complemented by a high resolution, which allows for detailed object detection.
- Enhanced Vertical Detection Accuracy: The sensor delivers a vertical angular resolution equivalent to 0.05 degrees, enhancing detection accuracy by 2.7 times compared to conventional products. This capability is essential for identifying three-dimensional objects, such as tires or other road obstacles, at distances of up to 250 meters.
- Superior Distance Resolution: The IMX479 features proprietary circuits that process each SPAD pixel’s data individually, improving the LiDAR’s distance resolution to 5 cm intervals. This level of precision is crucial for applications requiring detailed environmental mapping.
- High Photon Detection Efficiency: With a photon detection efficiency of 37% for the 940 nm wavelength, the sensor can detect objects at distances of up to 300 meters. This efficiency is achieved through an optimized on-chip lens shape and textured surfaces that enhance light absorption.
- Robust Performance in Bright Conditions: The sensor can maintain high detection accuracy even in bright light environments, where background light levels exceed 100,000 lux. This capability ensures reliable performance in various lighting conditions.
Technical Specifications
- Model Name: IMX479
- Effective SPAD Pixels: 105 × 1,568 pixels, approximately 164,000 pixels
- Vertical Effective dToF Pixel Count: 520 dToF pixels
- Image Size: Diagonal 15.8 mm (1-type)
- Recommended Light Source Wavelength: 940 nm
- SPAD Unit Cell Size: 10.08 μm × 10.08 μm
- Photon Detection Efficiency: 37% (940 nm wavelength)
- Response Speed: Approximately 6 nanoseconds
- Max Detection Distance: 300 meters
- Distance Precision at 300 meters: Minimum 5 cm equivalent
Evaluation and Development
To facilitate product evaluation and development, SSS has developed a mechanical scan LiDAR unit equipped with the IMX479 sensor. This unit will be made available to customers and partners, supporting their efforts in LiDAR development and product evaluation. Mechanical scanning involves using a rotating mirror to reflect the beam from a fixed laser light source, allowing for wide-area horizontal scanning.
Industry Implications
The introduction of the IMX479 sensor marks a significant advancement in automotive LiDAR technology. As the demand for autonomous driving solutions grows, innovations like the IMX479 will play a crucial role in enabling higher levels of automation and safety. The sensor’s high-speed, high-resolution capabilities position it as a critical component in the development of Level 3 automated driving systems, which allow for autonomous vehicle control under certain conditions.
Conclusion
Sony Semiconductor Solutions’ announcement of the IMX479 SPAD depth sensor represents a major step forward in the evolution of automotive LiDAR technology. By offering unmatched performance in terms of speed, resolution, and detection accuracy, the sensor is poised to enhance the capabilities of ADAS and automated driving systems. As the automotive industry continues to innovate, technologies like the IMX479 will be at the forefront of efforts to create safer and more reliable mobility solutions.
For those interested in learning more about this groundbreaking sensor and its applications, additional information is available on the official Sony Semiconductor Solutions website.
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