SPAD dToF Depth Sensor for
Automotive LiDAR Applications
- Home
- Products & Solutions
- Image Sensor
- Image Sensor for Automotive Use
- SPAD dToF Depth Sensor for Automotive LiDAR Applications
Overview
The Automotive Light Detection and Ranging(LiDAR), which can accurately detect and recognize road conditions and the positions and shapes of objects such as vehicles and pedestrians, is a technology that is becoming increasingly important for the spread of Advanced Driver Assistance Systems (ADAS) and the realization of Automated Driving.
A Single Photon Avalanche Diode(SPAD) is a pixel structure that uses “avalanche multiplication” to multiply electrons from a single incident photon, like a real world avalanche . It allows detection even when the incident light is weak. Distance measurement over long distances and with high accuracy are made possible by using this structure as the light receiving element in the SPAD ToF depth sensor. This sensor measures the distance to an object by detecting the Time of Flight (time difference )of a signal emitted from a light source until it returns to the image sensor, after being reflected by an object.
Technologies that Sony Semiconductor Solutions Corporation(SSS) has nurtured in CMOS image sensor development such as the back-illuminated structure, stacked structure, and Cu-Cu (copper-copper) connection*1 have been utilized in this product, to include the SPAD pixel and distance processing circuits in a single chip, realizing high resolution in a compact size.
By realizing high resolution, IMX459 has made it possible to measure distances rapidly with superior accuracy up to 300 m at 15 cm range resolutions*2. The product has improved reliability under the various harsh temperature and weather conditions required of automotive applications. The single-chip package also contributes to reducing the cost of LiDAR.
IMX479 integrates newly developed distance measurement circuits and SPAD pixels on a single chip, the new product has achieved a high-speed frame rate of up to 20 fps while delivering a high resolution of 520 dToF pixels with a small pixel size of 10 μm square.
*1) A technology used when a pixel chip (top) is stacked with a logic chip (bottom), to achieve electrical continuity by connecting the Cu (copper) pads to each other. This increases the freedom in the design, improves productivity, and enables a smaller size and higher performance compared with Through-Silicon Vias(TSV), where the upper and lower chips are connected by through electrodes around the circumference of the pixel area.
*2) When measuring an object of 1 m high and 10% reflectance, under cloudy daytime conditions with 6 pixels (H) x 6 pixels (V) in additive mode.
Features
IMX459
High-speed, high-precision distance measuring performance thanks to a stacked configuration with both 10 μm square SPAD pixels and distance measuring processing circuit
IMX459 employs a back-illuminated SPAD pixel structure that uses a Cu-Cu connection, to connect each pixel in the pixel chip (top) to the logic chip equipped with distance measuring processor circuits (bottom). Because this configuration places all circuits below light receiving pixels, it allows a high aperture ratio*3 and a high 24% photon detection efficiency rate. Even with its compact chip size, a high resolution of approximately 110,000 effective pixels (189 x 600 pixels) at a pixel size of 10 μm is achieved. This enables high-precision distance measuring at 15-centimeter range resolutions up to a distance of 300 meters, thereby contributing to improved LiDAR detection and recognition performance.
*3) Ratio of aperture section (section other than light-blocking sections) as viewed from the light incident side per pixel.
SPAD ToF depth sensor stacked configuration
(Top: point cloud, bottom: distance intensity image)
Imaging example of LiDAR with SPAD ToF depth sensor
(Top: SPAD pixels, bottom: distance measuring processing circuit)
IMX479
Delivering high-resolution and high-speed distance measuring performance simultaneously
IMX479 employs a dToF pixel unit composed of 3×3 (horizontal × vertical) SPAD pixels as a minimum element to enhance measurement accuracy using a line scan methodology. In addition, SSS’s proprietary device structure enables a frame rate of 20 fps*5, which is the fastest*4 for such a high-resolution SPAD depth sensor having 520 dToF pixels*4.
IMX479 enables the high-resolution and high-speed distance measuring performance demanded for an automotive LiDAR systems required in advanced driver assistance systems (ADAS) and automated driving (AD), contributing to safer and more reliable future mobility.
*4) According to SSS research (as of announcement on June 10, 2025)
*5) The frame rate may vary depending on horizontal FoV (Field of View) and its resolution.
Up to 20 fps frame rate, the fastest for a 520 dToF pixel SPAD depth sensor*4
IMX479 consists of a pixel chip (top) with back-illuminated dToF pixels and a logic chip equipped with newly developed distance measurement circuits (bottom) using a Cu-Cu connection on a single chip. This design enables a small pixel size of 10 μm square, achieving high resolution of 520 dToF pixels. The new distance measurement circuits handle multiple processes in parallel for even better high-speed processing.
These technologies achieve a frame rate of up to 20 fps,the fastest for a 520 dToF pixel SPAD depth sensor.*4 They also deliver capabilities equivalent to 0.05 degrees vertical angular resolution, improving the vertical detection accuracy by 2.7 times that of conventional products.*6 These elements allow detection of three-dimensional objects that are vital to automotive LiDAR, including objects as high as 25 cm (such as a tire or other objects in the road) at a distance of 250 m.
*6) Compared with SSS’ IMX459 1/2.9-type 100,000-effective pixel stacked SPAD ToF Depth Sensor for Automotive LiDAR systems.
Excellent distance resolution of 5 cm intervals
The proprietary circuits SSS developed to enhance the distance resolution of this product individually processes each SPAD pixel data and calculates the distance. Doing so successfully improved the LiDAR distance resolution to 5 cm intervals.
High, 37% photon detection efficiency enabling detection of objects up to a distance of 300 m
IMX479 features an uneven texture on both the incident plane and the bottom of the pixels, along with an optimized on-chip lens shape. Incident light is diffracted to enhance the absorption rate to achieve a high, 37% photon detection efficiency for the 940 nm wavelength, which is commonly used on automotive LiDAR laser light sources. It allows the system to detect and recognize objects with high precision up to 300 m away even in bright light conditions where the background light is at 100,000 lux or higher.
IMX459, IMX479
What is direct Time of Flight (dToF)?
dToF is a measurement method that measures the distance to an object based on the Time of Flight (time difference) of a signal emitted from a light source until it returns to the image sensor, after being reflected by an object.
Depth sensors with dToF use SPAD pixels, which can detect a single photon, so they can achieve high-precision depth measurement even from a long distance.
The mechanism of SPAD (single photon avalanche diode) pixels
On a dToF depth sensor, SPAD pixel is able to detect single photons. Breakdown Voltage (VBD)*7 is applied to the electrodes in the SPAD pixel. By setting Excess bias Voltage (VEX)*8 exceeding VBD to the electrodes, when the pixel is hit by photons the electrons generated in photoelectric conversion are amplified via avalanche multiplication. Then, the voltage between electrodes lowers to the breakdown voltage and avalanche multiplication is stopped. After the electrons generated by avalanche multiplication are collected and the voltage has returned to the breakdown voltage (quenching action), the voltage between electrodes is set to the excess bias voltage once again to enable detection of the photon (recharge action). This multiplication of electrons triggered by the arrival of the photon is known as Geiger mode.
*7) Voltage at which avalanche multiplication begins
*8) Voltage that exceeds the breakdown voltage (VBD)
Compliant with the feature safety standards for automotive applications, improving the reliability of LiDAR systems
Both IMX459 and IMX479 have been certified with Grade 2 of AEC-Q100, the standards for reliability testing of automotive electronic devices. Our development process is also compliant with ASIL-B (D) under ISO 26262, the international standards for the safety of road vehicles, dealing with feature safety aspects like failure detection, notification and control. This contributes to the improvement of the reliability of LiDAR systems.
Product Lineup
| Product | Number of effective pixels | Image Size [Type] |
Pixel Size V=H[μm] |
Dead Time [ns] |
PDE (Photon Detection Efficiency) [%] |
I/F |
|---|---|---|---|---|---|---|
| New IMX479 |
164K | 1 | 10.08 | Approx. 6 ns | 37 λ=940nm | MIPI CSI-2 |
| IMX459 | 100K | 1/2.9 | 10.08 | TBD | 24 λ=905nm | MIPI CSI-2 |
Specifications
| Product Specifications | ||
|---|---|---|
| Model name | New IMX479 |
IMX459 |
| Number of effective pixels | 105(H) x 1560(V) 164K SPAD pixels | 597(H) x 168(V) 100K SPAD pixels |
| Vertical effective dToF pixel count | 520 dToF pixels | 192 dToF pixels |
| Element size | 3(H) x 3(V) SPAD pixels | 3(H) x 3(V) SPAD pixels |
| Image size | Diagonal 15.8 mm (Type 1) | Diagonal 6.25 mm (Type 1/2.9) |
| Unit cell size | 10.08 µm(H) x 10.08 µm(V) | 10.08 µm(H) x 10.08 µm(V) |
| Substrate material | Silicon | Silicon |
| Operation mode | Line mode | Line mode / Array mode |
Technology
Find out more about ToF（Time of Flight） used in this product.
Applications
These products are leveraged in automotive camera/LiDAR.
Related Links
Commercialized the Industry’s First*4 Stacked SPAD Depth Sensor for Automotive LiDAR Systems:
Contributing to the Future of Safe and Secure Mobility through the Evolution of Automotive LiDAR Detection and Recognition Performance
Contact Us
For inquiries about Sony Semiconductor Solutions Group and products / solutions, specifications, quotation / purchase requests, etc., please contact us using the Inquiry form from the button below.