Introduction
Outside of the typical visible light spectrum lies a range of longer wavelengths,Ā the infrared range. This range is typically separated intoĀ fourĀ segments: Long Wave (LWIR)Ā 8-12Ā Āµm, Mid Wave (MWIR)Ā 3-5Ā Āµm, Short Wave (SWIR)Ā 1.0-2.5Ā Āµm, and Near (NIR)Ā 0.7-1.0Ā ĀµmĀ Infrared. The latter two are typically consideredĀ mostĀ similar toĀ visible wavelengthsĀ with a light source and a target. The longer wavebands areĀ emitted by objects due to their temperature.Ā
Though NIR and SWIR act similarly toĀ visibleĀ light, they are not visible to the human eye. As a result, these spectrums presentĀ valuableĀ informationĀ whichĀ can show artifacts or damage that wouldĀ otherwiseĀ not be seen.Ā Click hereĀ to see some examples of how SWIR is being used in existing applications today.Ā Ā
Pixel Architecture
Many CMOS sensorsĀ are able toĀ see into the NIR range with their standard architectureĀ but cannot see into the SWIR range.Ā These silicon sensors have an upper range limit around 1.0 Āµm.Ā ToĀ lookĀ deeper into the SWIR range,Ā InGaAsĀ isĀ used as aĀ sensorĀ material.Ā It isĀ a semiconductorĀ grown with a specific ratio ofĀ (Indium,Ā GalliumĀ and Arsenic)Ā giving itĀ a spectral responseĀ ofĀ 1.1-1.7Ā Āµm.Ā TheĀ typicalĀ drawback to these sensors is that they cannot see the shorter, visibleĀ colorĀ wavelengthsĀ due to the manufacturing process.Ā Ā
For applications that want to see in both the visible and SWIR ranges,Ā two sensorsĀ areĀ needed to seeĀ theseĀ independentlyĀ andĀ thenĀ their imagesĀ canĀ be mergedĀ into one. This can be challenging to do as theĀ cameras and captured imagesĀ need to have similar fields of view,Ā andĀ opticsĀ being positioned very close to each other to minimize anyĀ disparity. This process often has alignment issues in the final images that make them difficult to get the best resultsĀ forĀ a given application. New technology and sensorĀ substrates are being developed that are making it possible to overcome these challenges with only a few drawbacksĀ or sacrifices.Ā Ā
SonyāsĀ SenSWIRĀ TechnologyĀ
The demand for higher productivity is driving the growing interest in image capture in both the visible spectrum and SWIR wavelengths.Ā SenSWIRĀ from SonyĀ can captureĀ wavelengths from 0.4 ā 1.7Ā ĀµmĀ allowingĀ oneĀ image sensorĀ to see both the visible andĀ SWIR spectrums of lightĀ simultaneously.Ā For this reason, the market trend for SWIR sensors is promising and technical developments are progressing rapidly.Ā Do you already knowĀ SenSWIR?Ā
SonyāsĀ SenSWIRĀ technology,Ā leverages SonyāsĀ semiconductor processing and theirĀ copper-to-copper connectionĀ producing smaller pixels, not otherwise available withĀ InGaAsĀ sensors. As a result, smaller high-resolution cameras can be developed, which can support higher inspection precision.Ā
Image Source: https://www.sony-semicon.co.jp/e/products/IS/industry/technology/swir.html
The demand for higher productivity is driving the growing interest in image capture in both the visible spectrum and SWIR wavelengths. For this reason, the market trend for SWIR sensors is promising and technical developments are progressing rapidly.Ā
- Clever solution: A wide-band and high-sensitivity SWIR image sensor technology implemented by the combination of compound semiconductor InGaAs photodiodes and Si readout circuits through Cu-Cu bonding.
- Finer pixel pitch: Sonyās SWIR sensors feature smallest pixels in the industry (as of May 2020).
- Broad imaging: IMX990 and IMX991 sensors cover SWIR wavelengths from 0.4Ī¼m to 1.7Ī¼m.
- Visible and SWIR sensitivity in a single sensor is now possible.
Under visible light
Under SWIR imaging conditions
Image Source: https://www.sony-semicon.co.jp/e/products/IS/industry/technology/swir.html
Explore the advantages in a variety of applications
Sorting of Products
Ideal for applications such as sorting fruits and vegetables, as light in the SWIR band enables detection of moisture content, which is difficult to determine under visible light.
Foreign Material Inspection
Properties of light absorption and reflection in SWIR imaging are applied to distinguish substances that would be difficult to differentiate under visible light alone.
Semiconductor Inspection
Light in the SWIR band passes through material made of silicon. This aspect of SWIR imaging is applied in semiconductor production and inspection.
Temperature Estimation
Around hot objects, light in the SWIR band shines quite brightly. Temperature can be estimated from differences in brightness among several wavelengths. This is used to estimate the temperature of welds or other hot areas.
Remote Observation
Light in the SWIR band has longer wavelengths than visible light. This makes the light less susceptible to scattering, thus apply SWIR imaging successfully in remote observation.
Learn more details about the possibilities provided by Sonyās SWIR technology
The advances in performance and functionality introduced by the IMX990 and IMX991 pave the way for the development of SWIR industrial cameras and inspection equipment for a diverse range of applications such as inspection, identification, and measurement.Ā
Sensors
Sony IMX991-AABJ ES
Sony IMX991-AABA ES
Sony IMX990-AABJ ES
Sony IMX990-AABA ES
Evaluation Kits
Sony IMX991-AABJ EVB-Kit
Sony IMX991-AABA EVB-Kit
Sony IMX990-AABJ EVB-Kit