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What is photoluminescence ?
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Is it environmental products?
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 What is photoluminescence? |
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Lightlead photoluminescent materials (commonly called ”°glow-in-the-dark”±) has the ability to absorb light (sunlight, fluorescent, incandescent,etc) and then to emit light. When ambient darkness occurs, it becomes highly visible, lasting at least 10 hours.
Upon removal of the light source, the stored light is gradually released, the strongest glow is produced during the first 30 minutes of darkness, the most critical period following a power failure or other emergency. Then it fades over a period of time, when there is light again, it stores energy again. So the photoluminescence process is circulatory.
The bases of most photoluminescent products are photoluminescent pigments that can be incorporated into coat, paint, ink, fabric, ceramic glaze or porcelain enamel, glass, flexible and rigid molded plastics. Typical products include self adhesive flexible vinyl tapes, rigid PVC marker strips, and silk-screened signage. Photoluminescent fabric, enamel-coated sheet metal and ceramic tiles are also available. |
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How bright are these photoluminescent products?
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Many manufacturers refer to the extinction time of their products, which is defined as the time required for the afterglow to diminish to one masb (0.032 mcd/m2, or about 100 times the limit of human perception). In practice, this is very difficult to see unless your eyes are fully dark-adapted and you are in a completely dark environment.
For practical purposes, luminances of one to two millicandela per square meter are more appropriate limits for life safety applications, and even this assumes a smoke-free environment. Thus, zinc sulphide products are useful for perhaps 30 to 45 minutes after their excitation source has been extinguished. The afterglow of strontium aluminate products, on the other hand, can be visible for several days or more.
At the other end of the time scale, strontium aluminate products can provide surprising amounts of initial afterglow. For example, a four-inch square of material held a few inches away from a magazine page can provide enough light to read by, at least for the first minute or so. In addition, microprismatic retroreflectors and other brightness enhancing techniques can increase the materials luminance by several times. |
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Can photoluminescence replace traditional emergency lighting? |
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Lightlead photoluminescent materials were originally designed to complement existing emergency lighting systems but continuous improvements in luminance performance mean that in certain circumstances high quality photoluminescent products can replace emergency lighting. They can be sited at waist or skirting level so they can still function if the ceiling lights become obscured by smoke. Similarly, life saving appliances and fire fighting equipment become more visible and are easily located in an emergency. Some emergency lighting can take up to 15 seconds to activate. In these instances, photoluminesce |
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How do the materials work? |
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S £® SHOW photoluminescent materials contain purpose designed inorganic phosphor compounds that are energised in seconds by the ultra violet and blue light wavelength energy that is present in nearly all light sources.
This high-energy source is converted into a lower energy source of light. The lower energy light source is yellow-green, the colour most readily perceived by the human eye and as specified by safety signs standards.
S.SHOW photoluminescent materials are non-radioactive and non-toxic and provide a strong light source. They are also self-extinguishing, so they carry on working when they are most needed. |
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Is it environmental products? |
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Lightlead photoluminescent materials are non-toxic, non-radioactive and contain no phosphorus or lead, or any other hazardous element or chemical. The term phosphorence is sometimes used to describe luminescence, but Lightlead photoluminescent materials contain no phosphorus.
Lightlead photoluminescent materials differ from reflective materials, which amplify and increase relative brightness when light is applied. Fluorescent materials are quite different from photoluminescent materials. Fluorescent materials (such as the 3M fluorescent work zone film or a "hot pink" tag) actually serve to borrow nearby light energy in nearby wavelengths and concentrate the amount of light returning to the viewer in a certain (for example, day-glo orange) wavelength. Fluorescent films are especially useful in dawn and dusk viewing times, when they appear particularly bright.Lightlead photoluminescent materials require prior exposure to a light source in order to glow in the dark. |
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>> Photoluminescent standards
>> Material safety data sheet(MSDS) |
