Overview

In the industrial equipment fields, there is high demand for camera-based inspections for a diversity of purposes, and requirements for image sensor performance become increasingly stringent year after year. Against this backdrop, the scope of application for ultraviolet (UV) imaging cameras is expanding. By combining UV lighting and UV-compatible lenses, cameras equipped with UV image sensors can provide special visual information which ordinary cameras for visible light imaging cannot.

Ultraviolet is a spectrum of shorter wavelengths than those of visible light. For this property, it is utilized for detecting minute scratches and other defects that are undetectable in visible light. UV cameras can also identify objects of transparent materials such as plastic and PET, which may not be easily discernible in visible light, as these materials absorb UV rays at different rates. UV imaging thus has a potential for applications such as sorting materials.

The diagram below is a simple illustration of the light spectrum. UV (ultraviolet) is shorter in wavelength, between 10 and 400 nm, than visible light (400–780 nm). IMX487, Sony’s latest image sensor with a UV spectrum capability covers the range between 200–400 nm, which is a segment of UV spectrum that is suitable for industrial use, such as inspections.

[Fig. 1] Wavelength of light (ultraviolet 10nm to 400nm)

[Fig. 1] Wavelength of light (ultraviolet 10nm to 400nm)

Sony's UV Image Sensor

Technical Features

High-speed UV imaging enabled by incorporating global shutter function

IMX487, Sony’s latest image sensor with a UV spectrum capability, deploys Pregius S technology, a global shutter pixel technology, enabling it to deliver undistorted images even of fast-moving objects.

The back-illuminated pixel structure offers high flexibility of metal wiring design inside the image sensor, facilitating a high-spec frame rate at 193 fps (when operating in the 10-bit mode). It opens up new applications in areas that demand high speed operations, such as UV-based plastic material sorting at recycling plants.

Find out more about Pregius / Pregius S

Design specialized for UV imaging

Quartz glass, which has high UV transmittance, is used for the cover glass of the image sensor while the chip-on lens is also made using a highly-UV-transmissive material, together enabling to deliver the performance dedicated to UV imaging. (Top image in Fig. 2)
The unique light receiving structure specially designed for UV sensing realizes high sensitivity while minimizing noises. (Bottom image in Fig. 2)

Design specialized for UV imaging
reference image Zoom Zoom

Fig. 2 IMX487 in section view

Design specialized for UV imaging

Fig. 2 IMX487 in section view

Applications

Detection of fine scratches and defects

UV image sensors are used for detecting defects in various manufacturing processes. Ultraviolet light has a short wavelength and is easily scattered by even the slightest unevenness on the surface of an object. Using this property, UV image sensors can detect defects on microscopic objects such as semiconductor patterns. It can also visualize fine scratches on metal parts that are barely visible to the human eye, making it ideal for visual inspection of products and components. The high-definition image sensor IMX487 realizes both high sensitivity and low noise, enhancing the precision of inspections.

Comparing images of metal plate scratch inspection

Under visible light

Under visible light

Under UV light

Under UV light

Inspection of transparent resin coating

In electronics manufacturing, UV image sensors can be used to inspect the quality of resin coating. Resin coating is a colorless transparent material, but when photographed under UV light, the areas coated with the resin material appear black, while the areas without the coating appear white due to the reflection of the metal parts. This allows immediate identification of coating unevenness.

Comparing images of transparent resin coating

Comparing images of transparent resin coating
reference image Zoom 拡大アイコン

*The appearances of resins may vary depending on the type of resin used.

Comparing images of transparent resin coating

*The appearances of resins may vary depending on the type of resin used.

Related sectors

Electronics Manufacturing

Sorting materials

UV image sensor can be utilized at recycling sites. While plastics, glasses, and other transparent materials cannot be discerned easily with visible light cameras, UV cameras can be utilized, for example, at recycling plants for the purpose of material sorting, leveraging the varying degrees of UV transmittance of different materials. IMX487 can handle high-speed imaging of, for example, sorting machines by means of the global shutter feature, capable of capturing undistorted images of fast-moving objects.

Related sectors

Recycling

Discharge inspections

When electric power infrastructure suffers ageing degradation, its power cables may discharge electricity from the damaged part, which would then release ultraviolet radiation. Using UV cameras helps to easily identify deteriorated parts in the power system, making it a possibility to automate, and/or streamline labor costs of, facility maintenance. IMX487 has approximately 8.13 effective megapixels, and this multi-pixel UV image sensor can be deployed outdoor in remote places or for wide-area inspections.

Related sectors

Infrastructure Facility Inspection

Download

Opening up New Frontiers with Invisible Light - Leveraging UV Image Sensors

Introducing application examples of UV image sensors in 5 categories, arranged according to the viewpoint of the principle.

Ultraviolet (UV) Image Sensor

2-page summary of Sony's UV image sensors

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