Prismatic Optical Design
The principal purpose of prismatic glass optics is to improve lighting efficiency by reflecting maximum quantities of light and directing it precisely where it is needed with an optical device that will not deteriorate with time.
In addition to this, Holophane glass reflector/refractors are specifically designed to allow some light to transmit through the prismatic structure, creating a controlled upward light component above the luminaire resulting in brighter ceilings and roof structures with improved vertical illuminances and visual acceptability.
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| Downward light only | Downward light with controlled upward light |
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| Total internal reflection from an accurate 45°/90° glass prism. All light is reflected backwards. | Holophane glass reflector/refractors allow some
light to transmit whilst the majority is reflected. |
Self Cleaning EffectThe open bottom and open top reflector design of Holophane industrial luminaires uses the heat generated by the lamp to create a constant air flow through the reflector. This is called the 'Venturi effect'. Dirt particles pass through the reflector and out of the open top, keeping the smooth inner surface of the reflector/refractor cleaner for longer. When cleaning is required, a simple wiping of the smooth inner surface will restore ‘as new’ efficiency. |
Venturi effect self-cleaning airstream |
Glass Reflector/RefractorThe major advantage of glass over aluminium or plastic is its low electrostatic charge, which makes it less attractive to dust and dirt accumulation over time. A glass reflector/refractor has a much lower light depreciation over time than either aluminium or plastic. Fewer luminaires are required, significantly reducing installation, operating and maintenance costs. |
Electrostatic Charge |
Luminaire MaintenanceThe graph below shows the Holophane glass reflector/refractor maintenance factors over a 10 year period without cleaning. These curves can be used with confidence to calculate accurate illuminance levels throughout the chosen maintenance life of the installation. The lower dirt depreciation of Holophane industrial luminaires ensures more light from fewer luminaires yielding lower operating costs. |
Prismpack Example |
Years installed without cleaning |
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