Short Wavelength Infra-Red Image Sensor Technology SenSWIR™
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Image Sensor for Industrial Use

Short Wavelength Infra-Red
Image Sensor Technology SenSWIR™

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Overview

SenSWIR is a wide-band and high-sensitivity SWIR image sensor technology implemented by the combination of compound semiconductor InGaAs photodiodes and Silicon readout circuits through Cu-Cu bonding.

SWIR light (shortwave infrared light) penetrates and is absorbed by different substances than visible light, so its attributes can be applied in a variety of different situations.

SenSWIR

*) SenSWIR and logo are registered trademarks or trademarks of Sony Group Corporation or its affiliates.

Technical Features

Higher pixel count, smaller systems

Creating SWIR sensors with smaller pixels than in current industrial CMOS image sensors has been challenging with conventional bump bonding, because a certain bump pitch must be maintained to bond the indium-gallium-arsenide (InGaAs) photodiode layer to the silicon readout circuit layer. With SenSWIR technology, Cu-Cu connection*1 enables a finer pixel pitch and smaller pixels. As a result, smaller high-resolution cameras can be developed, which can support higher inspection precision.

*1)A technique that provides electrical conduction by bonding copper pads, as the pixel chip (top) and logic chip (bottom) are stacked. Advantages over the previous through-silicon via approach (which electrically connects top and bottom chips at the edge of the pixel area) include smaller systems and improved performance, which affords greater freedom in design and promises higher productivity.

Broad imaging that extends to the visible spectrum

The top indium-phosphorus (InP*2) layer inevitably absorbs some visible light, but applying Sony's SWIR sensor technology makes this layer thinner, so that more light reaches the underlying InGaAs layer. The sensors have high quantum efficiency even in visible wavelengths. This enables broad imaging of wavelengths from 0.4 μm to 1.7 μm. A single camera equipped with the sensor can now cover both visible light and the SWIR spectrum, which previously required separate cameras. This results in lower system costs. Image processing is also less intensive, which accelerates inspection. These advances promise to expand the scope of inspection significantly.

*2) Substrate that forms the base of the InGaAs layer.

Broad imaging that extends to the visible spectrum
Reference Zoom Zoom
Broad imaging that extends to the visible spectrum

What's SWIR?

Generally, light with a wavelength of 400 nm to 780 nm is referred to as visible light, and light with a wavelength of 780 nm to 106 nm as infrared light. The wavelength band of SWIR is from 900 nm to 2,500 nm, which is the region of infrared light closest to visible light. Image sensors equipped with SenSWIR technology are capable of broad imaging over the range of 400 nm - 1,700 nm, including visible light as well as SWIR light.

What's SWIR?

Applications

Sorting fruits and vegetables

Water becomes black in an image taken with a SWIR image sensor set at the wavelength of 1,450 nm because water absorbs the light at this wavelength. Since this makes it possible to detect moisture contained in objects, it can be used for applications such as fruit and vegetable sorting.

Example of sorting fruits by detecting dents or scratches

Under visible light

Under visible light

Under SWIR (1,450 nm)

Under SWIR (1,450 nm)

SWIR imaging makes the moisture concentrating in dents on the apples visible.

Related sectors

Agriculture and Farming

Container content inspections

In food manufacturing processes, performing final content inspections is difficult if the food packages are opaque. In some cases contents are pinched in the sealing part when the package is closed, which are also hard to detect.

Even if packages appear opaque in the visible range, it may be possible for light in SWIR wavelengths to penetrate them and allow their contents to be observed. By using this property, the inner areas of packages can be checked non-destructively and pinching errors can also be detected.

Example of detecting content conditions by observation that penetrates through a plastic container

Under visible light

Under visible light

Under SWIR (1,550 nm)

Under SWIR (1,550 nm)

Explanation of photo: SWIR imaging makes it possible to check the content of opaque containers.

Related sectors

Food/Medicine/Cosmetic Manufacturing

Contaminant detection

In food product manufacturing, inspections to check for the introduction of contaminants are essential. However, if contaminants that have been mixed in with products are similar in color to the products themselves, it may be difficult to identify them using only visible light.

Utilizing the absorption and reflection properties of SWIR-band light can make it possible to perceive differences between substances that are difficult to see with visible light alone. By using these attributes, SWIR image sensors can be applied toward uses such as contaminant detection.

Example of contaminants mixed in with food products

Under visible light

Under visible light

Under SWIR (1,300 nm)

Under SWIR (1,300 nm)

SWIR imaging makes it possible to distinguish between food products (black beans) and black-colored contaminants.

Related sectors
Food/Medicine/Cosmetic Manufacturing

Sorting materials

There are many different types of plastics, and since each type requires a suitable method of recycling, the first step at recycling sites is to sort them apart from each other.

Since plastics are transparent in the visible range, the properties of each type of material cannot be identified, but by examining them with light in SWIR wavelengths (particularly multiple wavelengths), it will be possible to determine their properties and sort them accordingly.

Related sectors

Recycling

Positioning in Semiconductor Manufacturing

Due to the miniaturization of semiconductor devices in recent years, high accuracy has become required even in layering processes for silicon wafers. In order to raise their accuracy, it is important to accurately align marks used for wafer positioning.

Light in SWIR wavelength bands has the property of penetrating the silicon layers of wafers, so applying SWIR image sensors can make it possible to clearly confirm positioning marks. High definition SWIR image sensors from Sony are also anticipated to be used to improve edge detection accuracy.

Example of imaging by penetrating silicon wafers

Under visible light

Under visible light

Under SWIR (1,550 nm)

Under SWIR (1,550 nm)

The photograph on the right was taken under SWIR, so the resolution chart under the silicon wafer can be seen. Furthermore, high resolution SXGA imaging is possible, so even small marks can be detected with high accuracy.

Related sectors

Semiconductor Manufacturing

Temperature monitoring

Image sensors can perceive differences in the temperatures of substances as differences in luminance. Among them, substances at temperatures of roughly 250ºC or higher emit light in the SWIR band, so SWIR image sensors can be used in applications for monitoring high temperatures of 250ºC or higher. This characteristic is expected to be applied in the steel industry.

Example of monitoring the temperature at the tips of soldering irons

Under visible light

Under visible light

Under SWIR (1,550 nm)

Under SWIR (1,550 nm)

In the SWIR image, it is possible to confirm not only that the tips of the soldering irons have become hot, but also to identify their differences in temperature.

Related sectors

Heavy industry and plant manufacturing

Remote monitoring

In remote monitoring, airborne micro-particles can cause far-off targets to become blurred, making it difficult to accurately capture them with cameras. Comparatively, SWIR-band light, which has longer wavelengths than visible light, has the attribute of being affected to a lesser degree by airborne micro-particles than visible light, making it easier for far-off targets to be captured clearly. SWIR image sensors can therefore be utilized in applications for remote monitoring.

Related sectors

Remote and Wide-area Monitoring

Observation of agricultural lands

At agricultural sites, initiatives to observe agricultural lands from the sky with cameras are currently proceeding. Now that it has become possible to understand the growth conditions of crops, limited additional fertilizing and yield forecasts based on data can also be implemented.

However, it is not a simple task to make judgments on growth conditions using only color data. If SWIR image sensors are used, moisture content can be visualized so growth conditions and distribution according to moisture volume can also be expressed visually, and more accurate judgments can be made.

Related sectors

Agriculture and Farming

Download

Image Sensors with SenSWIR Technology

Image Sensors with SenSWIR Technology

Introducing the details of the technology used in this SWIR image sensors

SWIR Image Senser Overview

2-page summary of Sony's SWIR image sensors

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