Patent Application
20210308293
The present disclosure pertains to the field of lighting devices and, more specifically, proposes a safeguarded germicidal lighting device.
UV light is known to be effective in killing bacteria and viruses and thus has been used in germicidal lighting applications. It is also known that direct exposure of human skin to UV light may lead to skin cancer or other health-related issues. As a result, UV-based germicidal lighting device is generally placed in a concealed environment or at an upper room location to avoid directly shining on people. However, there are situations where it is necessary or desirable to use UV light to clean viruses and bacteria on a desktop surface at close distances. In these situations, the UV light should be turned on only when no one is around. This approach requires user compliance and is used in medical environments where users are properly trained in safety practices. In a residential setting with children, however, it is not practical to rely on user compliance with the safety practices of UV germicidal lighting. Hence a better approach, with a guaranteed safeguard against the misuse of UV germicidal lighting, is necessary.
The present disclosure introduces a dual-mode lighting device that can be used for general lighting as well as germicidal lighting. In the germicidal lighting mode, an automatic safeguard mechanism is provided to prevent direct human exposure to UV light.
In one aspect, the lighting device comprises a light head, two light sources, and a safeguard mechanism. The light head houses the two light sources. The first light source emits predominantly UV light (<400 nm) for germicidal illumination, and the second light source emits predominantly visible light (>400 nm) for general lighting. The lighting device may operate in two modes. The first operation mode is the general lighting mode. In this mode, only the second light source is on for providing general lighting. The second operation mode is the germicidal lighting mode. In this mode, the first light source is on for providing germicidal lighting. The safeguard mechanism is responsible for preventing the first light source in the germicidal lighting mode from turning on and causing accidental human exposure to the UV light from the first light source.
The two operation modes may be implemented by one switch with a two-stage setting, where Stage 1 is for the general lighting mode and Stage 2 is for the germicidal lighting mode. Alternatively, two switches may be used, where Switch 1 is used for turning on the general lighting mode and Switch 2 is used for turning on the germicidal lighting mode. Under such implementation, it is foreseeable that the first light source and the second light source may be turned on at the same time. This may be desirable for some applications. For example, for a hallway or stairwell fixture, it is necessary to have the second light source (visible light) on when the first light source (UV light) is on in order to provide sufficient lighting for a safety camera to function properly.
There are different implementations of the safeguard mechanism for turning on the first light source. In some embodiments, the safeguard mechanism may be a pressable switch such that the first light source turns on while a user presses the switch continuously. Once the user releases the switch, the first light source shuts off. With the safeguard mechanism thus implemented through a pressable switch, a user must consciously activate the first light source continuously, thus effectively preventing accidental use of the first light source and avoiding accidental human exposure to the UV light from the first light source.
In some other embodiments, the safeguard mechanism may be a motion sensor. The motion sensor automatically shuts off the first light source in the germicidal lighting mode upon detecting motion in the surrounding area of the lighting device. With the motion sensor as a safeguard mechanism, it shuts off the first light source when an individual comes too close to the light device in the germicidal mode, thus freeing parents from concerns of accidental exposure of their children to UV light. There is no restriction on the type of motion sensor. It may be IR based or microwave based or even sound based, so long as it provides adequate motion detection.
In some other embodiments, the safeguard mechanism may be a timer. The timer sets the on-time duration of the first light source in the germicidal lighting mode, e.g., to 15 minutes, thus protecting a user from being exposed to UV light for more than 15 minutes. Different safeguard mechanisms may be combined for a more effective safeguard. For example, a motion sensor can be used together with a timer for the present disclosure such that if a user comes near the light device when the first light source is on, the motion sensor would shut off the first light source. And the timer would shut off the first light source after the on-time duration expires even if no motion is detected during that time. There are two benefits of this combined safeguard approach. Firstly, it saves energy that would be lost due to unnecessary UV lighting. Secondly, it serves as a double safeguard in case the motion detector malfunctions.
When using narrow-band UV light as the first light source, no visible light is emitted from the first light source while it is on, since UV light (<400 nm) is outside the visible wavelength spectrum (>400 nm). This means that a user may not be able to tell whether the first light source is on by simply looking at the first light source. It is necessary to have another safeguard mechanism for informing the user whether the first light source is on or not. Therefore, in some embodiments, an LED indicator light may be used to indicate the on/off status of the first light source.
There are different options for the technology of the first and the second light sources. In some embodiments, the first light source may be UV LEDs, and the second light source may be regular white light LEDs. Moreover, the technology of the UV LEDs enables the creation of narrow band UV LEDs for a particular UV wavelength range. Thus, the first light source may further comprise a third light source and a fourth light source. While the third and the fourth light sources both emit predominantly UV light (<400 nm), the main wavelength of the third light source is higher than the main wavelength of the fourth light source. Furthermore, in some embodiments, the third light source may be UVA LEDs emitting predominantly light in 315-400 nm wavelength range and the fourth light source may be UVC LEDs emitting predominantly light in 100-280 nm wavelength range. It is known that UVA light and UVC light each have a killing effect on certain bacteria and viruses. By using both UVA LEDs for the third light source and UVC LEDs for the fourth light source, the germicidal effect of the light device of the present disclosure is maximized.
The germicidal effect of the UV light is proportional to the coverage area of the germicidal light source. Thus, the wider the UV light coverage area, the wider the area that is cleaned by the UV light. Therefore, in some embodiments, the light head may be of elongated shape and the first and the second light sources may be of elongated shape, in order to provide a wider germicidal area.
In some embodiments, the light device also has an upholder. One end of the upholder connects to the light head, and the upholder supports the weight of the light head. In some cases, the upholder will be mounted on a base such that the lighting device of the present disclosure may be a free-standing lighting fixture. In some other cases, the upholder may be a ceiling-mounted chain or pole such that the light device of the present disclosure may be a pendant-mounted lighting fixture.
The germicidal effect of the UV light is proportional to the intensity of the UV light source. When the energy consumption of the UV light source is kept constant, the intensity of the UV light source remains constant for any given distance. However, if the distance of the UV light source to the surface to be cleaned is decreased, the germicidal cleaning effect may be increased without increasing the energy consumption of the UV light source. Therefore, in some embodiments, the upholder may have an adjustable mechanical structure for adjusting the position of the light head, and in the germicidal lighting mode, the first light head may be positioned within 30 cm of the surface illuminated by the lighting device for more effective germicidal cleaning.
The accompanying drawings are included to aid further understanding of the present disclosure, and are incorporated in and constitute a part of the present disclosure. The drawings illustrate a select number of embodiments of the present disclosure and, together with the detailed description below, serve to explain the principles of the present disclosure. It is appreciable that the drawings are not necessarily to scale, as some components may be shown to be out of proportion to size in actual implementation in order to clearly illustrate the concept of the present disclosure.
Various implementations of the present disclosure and related inventive concepts are described below. It should be acknowledged, however, that the present disclosure is not limited to any particular manner of implementation, and that the various embodiments discussed explicitly herein are primarily for purposes of illustration. For example, the various concepts discussed herein may be suitably implemented in a variety of lighting apparatuses having different form factors.
The present disclosure introduces a lighting device that comprises a light head, two light sources, and a motion sensor. The light head houses the two light sources. The first light source emits predominantly UV light (<400 nm) for germicidal illumination, and the second light source emits predominantly visible light (>400 nm) for general lighting. The lighting device may operate in two modes. The first operation mode is the general lighting mode, where the second light source is on for providing general lighting. The second operation mode is the germicidal lighting mode, where the first light source is on for providing germicidal lighting. The safeguard mechanism prevents the first light source in the germicidal lighting mode from turning on and causing accidental human exposure to the UV light from the first light source.
Although the techniques have been described in language specific to certain applications, it is to be understood that the appended claims are not necessarily limited to the specific features or applications described herein. Rather, the specific features and examples are disclosed as non-limiting exemplary forms of implementing such techniques.
As used in this application, the term “or” is intended to mean an inclusive “or” rather than an exclusive “or.” That is, unless specified otherwise or clear from context, “X employs A or B” is intended to mean any of the natural inclusive permutations. That is, if X employs A; X employs B; or X employs both A and B, then “X employs A or B” is satisfied under any of the foregoing instances. In addition, the articles “a” and “an” as used in this application and the appended claims should generally be construed to mean “one or more,” unless specified otherwise or clear from context to be directed to a singular form.
