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A surface-sterilising light fixture

Figure newWEB© Appleyard Lees IP LLP

Worktop surfaces, including those in kitchens that are easily contaminated, are usually cleaned using antibacterial chemicals. Such chemicals can be harsh on surfaces and human skin, and may also be harmful to the environment. Plastic containers used for storing and transporting the chemicals may end up in landfill, and excess chemicals may be washed away into drainage systems.

In November 2021, Sensio Limited was granted UK patent GB2586572B titled Light fixture, which claims a light fixture for sterilising a surface in a kitchen. 

The light fixture comprises a visible light source, an ultra-violet (UV) light source that generates UV emissions to sterilise a surface, a sensor unit configured to sense the ambient environment of the light fixture, and a timer defining a time period during which the UV light source may be active. 

The sensor is configured to sense movement and luminosity in the ambient environment, and to deactivate the UV light source in response to at least one of sensing movement in the ambient environment and sensing the luminosity being greater than a pre-determined threshold. 

The UV light source is reactivated if no movement is sensed within a pre-determined period of time, the luminosity is below the pre-determined threshold, and the timer indicates that it is the time period in which the UV light source may be active. 

In Figure 1, a light fixture (100) is shown mounted in the vicinity of a work surface (160) to be sterilised. The light fixture may be mounted on a wall adjacent to the work surface, or on the underside of a cabinet (170) positioned above the work surface. 

In visible light mode, a visible light source (110) of the light fixture will be active while a UV light source (120) will be inactive.

The visible light mode and UV light mode may be activated at the same time, however, it is generally preferred that only one mode is activated at any one time.

Activation of the UV light source by the sensor unit (130) may require that the visible light source is inactive. 

The sensor unit (130) is configured to activate and deactivate the UV light source. In particular, the sensor unit is configured to deactivate the UV light source in response to an external stimulus, thereby preventing, for example, the UV irradiation of a person. 

Optionally, the sensor unit may be configured to detect movement via a passive infrared sensor (PIR, 131) and luminosity via a photodetector (PD, 132) or photocell, as shown in Figure 2 – a spotlight embodiment of the light fixture. 

The sensor unit may be configured by a manufacturer or user with a trigger condition or threshold for activating or deactivating the UV light source. For example, the trigger condition may be the activation of the UV light source when no movement is detected by the PIR sensor over a certain period of time. 

Figure 3 shows another example of the light fixture, which further includes a timer (140). The timer may provide a time period in which activation of the UV light source is allowable. 

Therefore, in addition to the trigger conditions, including, for example, no movement sensed for a pre-determined period of time and luminosity below a pre-determined threshold, the activation of the UV light source may further require the timer to indicate an allowable time period.

The patent further claims a lighting strip including the light fixture, as well as a cabinet including the light fixture or the lighting strip. 

Read the full patent here.

This article first appeared in the February 2022 issue of Materials World, the member magazine of the Institute of Materials, Minerals and Mining.