- AS7331 from ams OSRAM provides separate sensor channels for UV-A, UV-B and UV-C - a new combination in a CMOS sensor
- A small device in a radiation-hardened surface-mount package, the AS7331 enables manufacturers to implement UV monitoring in cost-sensitive products for home use
- AS7331 allows manufacturers to accurately limit emissions from a UV-C light source to the required dose, improving performance, saving power and giving better value to end users
The AS7331, which is aimed at the consumer and industrial markets, offers very high sensitivity and high dynamic range. Customers also benefit from the cost efficiency of CMOS device fabrication.
High sensitivity of up to 421 counts/(µW/cm2) in the UV-A range means that the AS7331 can detect biofluorescence – a function required in water quality monitoring – or partial discharges in electric motors. Low-cost UV sensor chips on the market today are not sensitive enough to detect such weak UV signals. High dynamic range of 3.43E+10 gives product designers the flexibility to implement UV monitoring under both strong and weak sources of radiation. At 125µs, minimum measurement time is four times faster than the next best UV sensor currently available in the consumer market.
Markus Busz, senior product manager for spectral sensing at ams OSRAM, said: ‘The introduction of the AS7331 means that high-sensitivity UV dosage monitoring is now affordable enough to be built into devices for home use such as robotic floor cleaners, coffee brewing machines and home, water, and air purifiers. It fills a new position in the market between low-cost UV sensors which offer very low sensitivity, and high-performance, lab-grade UV sensors which are too expensive for devices intended for home use.’
The sensor is also suitable for applications such as UV curing and phototherapy. Markus Busz added: ‘Today, consumer disinfection and purification products typically include no UV-C monitoring capability because of the high cost of existing UV-C sensors. In the absence of accurate dosage information, these products are set to produce very high radiation and treatment times to ensure that the minimum necessary dosage is exceeded. This wastes power and accelerates the aging of UV light sources and irradiated materials. The launch of the AS7331 enables manufacturers to accurately limit emissions from a UV-C light source to the minimum necessary, improving performance and giving better value to the end user.’
By combining UV-A, UV-B and UV-C monitoring in a single device, the AS7331 also enables manufacturers to save space and reduce bill-of-materials cost in multi-function applications. For instance, in water purification systems the AS7331 can analyze the quality of the water by measuring the absorption of UV-A light. It can then measure UV-C radiation to check that a sufficient dose is administered to fully purify the water.
Precise optical performance characteristics
The AS7331 is a three-channel sensor which uses interference filters to produce precisely characterized responsivity to radiation in the UV-A (315nm-410nm), UV-B (280nm-315nm) and UV-C (240nm-280nm) wavelength bands. The filters also provide excellent rejection of interference from ambient visible and near infrared light sources.
The AS7331 features an internal temperature sensor to support temperature compensation of measurement outputs. Digital measurements of radiant intensity are supplied in up to 24-bit resolution via a 16-bit I2C interface output.
Low power consumption makes the AS7331 suitable for use in mobile or battery-powered products such as robotic floor cleaners. Operating current in active measurement mode is a typical 1.5mA at a 3.3V supply voltage, and the device draws a maximum current of just 970µA in stand-by mode.
Housed in a 16-lead OLGA package, the AS7331 has a footprint of 3.65mm x 2.60mm, and is 1.09mm high. The AS7331 UV sensor is complemented by a wide range of UV LEDs from ams OSRAM, such as the new OSLON® UV 6060. This high-power UV-C LED offers market-leading wall-plug efficiency at highest germicidal effectiveness.
The AS7331 UV sensor is available for sampling now. Mass production is expected to start in the first quarter 2023.
AS7331 from ams OSRAM provides separate sensor channels for UV-A, UV-B and UV-C - a new combination in a CMOS sensor
Image: ams OSRAM
AS7331 allows manufacturers to accurately limit emissions from a UV-C light source to the required dose, improving performance, saving power and giving better value to end users
Image: ams OSRAM
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About ams OSRAM
The ams OSRAM Group (SIX: AMS) is a global leader in optical solutions. By adding intelligence to light and passion to innovation, we enrich people’s lives. This is what we mean by Sensing is Life.
With over 110 years of combined history, our core is defined by imagination, deep engineering expertise and the ability to provide global industrial capacity in sensor and light technologies. We create exciting innovations that enable our customers in the consumer, automotive, healthcare and industrial sectors maintain their competitive edge and drive innovation that meaningfully improves the quality of life in terms of health, safety and convenience, while reducing impact on the environment.
Our around 23,000 employees worldwide focus on innovation across sensing, illumination and visualization to make journeys safer, medical diagnosis more accurate and daily moments in communication a richer experience. Our work creates technology for breakthrough applications, which is reflected in over 15,000 patents granted and applied. Headquartered in Premstaetten/Graz (Austria) with a co-headquarters in Munich (Germany), the group achieved over EUR 5 billion revenues in 2021 and is listed as ams-OSRAM AG on the SIX Swiss Exchange (ISIN: AT0000A18XM4).
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