Chongfan Technology
News
02
2024
-
12
Image sensor technology continues to break through, and short-wave infrared imaging is gradually becoming mainstream.
Author:
According to Mems Consulting, shortwave infrared (SWIR) imaging technology has been applied in military, defense, satellite imaging, anti-counterfeiting, and cultural relic analysis for decades. However, due to the high cost and complexity of manufacturing indium gallium arsenide (InGaAs) image sensors, shortwave infrared cameras have not been widely used in the industrial sector until now. Nevertheless, recent breakthroughs in image sensor technology have led to the development of low-cost, compact shortwave infrared cameras with extended spectral capabilities, which have been validated in machine vision applications ranging from food and beverage to waste recycling.
The prospects for shortwave infrared sensors are bright.
In the past, it was challenging to manufacture InGaAs image sensors with pixels smaller than industrial-grade CMOS image sensors using traditional pixel-level bump bonding technology. This technology requires a certain bump spacing to bond the InGaAs photodiode layer to the silicon readout circuit layer. Sony's new SenSWIR technology employs copper-copper (Cu-Cu) direct bonding interconnect technology, allowing the pixel chip and logic circuit chip of stacked CMOS image sensors to be directly interconnected without the need for dedicated connection areas, enabling the production of image sensors with smaller pixel spacing and pixels.
With the development of shortwave infrared sensors (such as Sony's SenSWIR), machine vision manufacturers now have more options for shortwave infrared cameras at lower prices.
Sony's hybrid shortwave infrared technology was delayed in its release in 2021 due to the impact of the COVID-19 pandemic, but it has now begun to be launched on a large scale. Today, many machine vision camera manufacturers have introduced smaller, higher-resolution, and lower-cost shortwave infrared cameras, with detection wavelength ranges covering 400 to 1700 nm.
According to Mems, in the field of shortwave infrared image sensors, onsemi recently acquired SWIR Vision Systems, which developed shortwave infrared sensors based on colloidal quantum dot (CQD) thin-film photodiodes manufactured on silicon readout wafers. These nanoscale semiconductor materials enable CQD-based sensors to image in the wavelength range of 400 to 1700 nm, while also extending to 2100 nm. Through this acquisition, onsemi plans to combine its silicon-based CMOS image sensors and manufacturing technology with CQD technology to provide highly integrated shortwave infrared sensors at lower costs and greater volumes.
The prices of shortwave infrared cameras have significantly decreased, and with the completion of this acquisition by onsemi, costs are expected to drop further, providing machine vision manufacturers with a richer and more economical selection of shortwave infrared cameras. In fact, advancements in shortwave infrared imaging technology and the reduction in entry costs have already sparked a huge response in the machine vision field. Currently, shortwave infrared imaging technology has become one of the fastest-growing areas in the machine vision market. Market research firm Yole Group predicts that due to technological advancements, stable demand, and cost reductions, the compound annual growth rate of the shortwave infrared imaging sensor market will reach 28%, with the market size rapidly growing from $89 million in 2022 to $395 million by 2028.
Breaking the imaging barrier.
Another novelty of the new shortwave infrared sensor technologies from Sony and onsemi is that their sensors can now cross the 1 µm imaging barrier, providing a typical usable spectral response of 400 to 1900 nm. In the past, traditional InGaAs shortwave infrared sensors had almost no response in the visible range, with a usable range around 1 μm. Similarly, silicon-based CMOS image sensors also lose response at 1 μm, which is why it is referred to as the '1 μm barrier' in machine vision and imaging fields. The new shortwave infrared image sensors can now provide continuous response across the visible and shortwave infrared spectral ranges, thereby expanding the multispectral imaging applications in the machine vision market.
Multispectral imaging technology is driving many emerging imaging and machine vision applications, including agricultural applications. For example, multispectral cameras can be used to distinguish color-similar green plants, separate weeds from target crops, identify fruits in leaves, pick stones or other objects from the soil, or assess moisture content. In other areas, the application of multispectral imaging technology in waste recycling is also becoming increasingly widespread, as multispectral cameras can sort specific types of materials, such as high-density polyethylene (HDPE), from waste, which is too costly and data-intensive for hyperspectral imaging technology.
Response from LED manufacturers.
Even before the development of these new technologies, shortwave infrared systems have proven to be very useful in machine vision applications that require imaging beyond visible light. For example, in food inspection, shortwave infrared cameras can identify damaged or bruised fruit beneath the surface or detect food through plastic packaging. In other applications, shortwave infrared cameras are also very useful, such as detecting fill levels in non-transparent containers, identifying moisture content in packaging, anti-counterfeiting, wafers, and solar cell production.
For system integrators experienced in machine vision technology, deploying shortwave infrared cameras is not fundamentally different from visible light imaging systems. Today, as the cost threshold decreases, the demand and deployment of shortwave infrared cameras are rapidly increasing, as this technology provides machine vision users with a very useful new tool. The development of image sensors has driven the popularization of shortwave infrared technology, and lighting manufacturers need to keep pace.
Although some manufacturers are quickly bringing lenses suitable for shortwave infrared imaging systems to market, the pace of lighting manufacturers has been relatively slow due to the limitations and corresponding high costs of shortwave infrared LED technology. However, with advancements in technology and growing demand, LED manufacturers are adapting to the new market changes. Novel shortwave infrared LEDs can produce more light output and less heat per watt of power while also increasing the absolute intensity of shortwave infrared light output.
Although shortwave infrared LED lighting is still a custom or semi-custom product for most lighting manufacturers, several manufacturers in the market have begun to offer standard products at shortwave infrared wavelengths, and the number of options is also increasing. Currently, shortwave infrared lighting products on the market cover wavelengths from 1050 nm to 1550 nm, with multi-zone lighting products that combine different wavelengths in one housing.
Multi-source controllers drive multispectral technology forward.
Multi-source controllers are also essential components for building the next generation of multispectral machine vision systems. Multispectral imaging involves capturing multiple images at specific wavelengths to display the characteristics of the target object in narrowband responses. Detection applications may be relatively simple, such as analyzing a single image with software, treating it as monochromatic detection. However, more commonly, a series of images are fused into a multispectral image through weighted filters, or compared with reference images for addition, subtraction, or differentiation to achieve the desired imaging results.
To simplify the programming and acquisition process of these images, the newly launched lighting controller provides a programmable sequence and a four-channel constant current LED driver in a single package. This controller can be used with linear, ring, or spherical multi-channel lighting, each offering three or four channels. Through a TCP/IP interface, this controller allows users at any level to intuitively program any type of imaging sequence.
With these new technologies, users can select wavelengths from 420 nm to 1650 nm, choosing each available channel individually according to the specific needs of their applications. These advancements, along with the latest short-wave infrared cameras, mean that today's machine vision users can access better and richer multispectral imaging technologies at a lower entry cost than ever before. The prospects for multispectral imaging technology across a broader range of wavelengths are very promising.
LATEST NEWS
Thank you for visiting the official website of Chongfan Technology. If you have cooperation intentions or suggestions, please contact us through the following methods, and we will reply as soon as possible, thank you!
Address: Room 403, Building 6, Phase III of R&D, No. 36 Xiyong Avenue, High tech Zone, Chongqing, China.
Telephone: +86-13658337211
E-mail: Sales@cfkeji.net
Website: www.cfkeji.net
Mobile Version
