Adjusting the transmittance of lighting glass is crucial for balancing optical design and decorative effects. Coating technology, through innovative material selection and process technology, enables precise control from high transmittance to semi-transparency, meeting the lighting and aesthetic requirements of diverse scenarios. Anti-reflection (AR) coatings improve transmittance by reducing the surface reflectivity of the lighting glass. This approach involves depositing a low-refractive-index material (such as silicon dioxide or magnesium fluoride) onto the surface, forming an optical interference layer. This coating reduces light reflection losses on the glass surface, allowing more light to penetrate, increasing transmittance by 5%-10%. In lighting, this technology is often used in applications requiring high-brightness transmission, such as transparent lampshades for chandeliers and wall sconces. It ensures sufficient light distribution while preventing glare caused by reflected light.
Diffuse reflective coatings achieve uniform light transmission by scattering light. Their core approach is to create microscopic structures (such as particles or textures) on or within the lighting glass to diffusely reflect light. For example, a coating containing titanium dioxide or aluminum oxide particles is sprayed on the inner layer of lighting glass. Light passing through it is scattered and evenly distributed by the particles, avoiding the brightness differences caused by direct light. This coating is suitable for lighting fixtures that require softer light, such as table and floor lamp shades, creating a warm and comfortable lighting atmosphere while maintaining a certain degree of light transmittance.
Dimmable coating technology dynamically adjusts light transmittance through electric or optical field control. PDLC (polymer dispersed liquid crystal) coating is a typical example. This coating consists of two pieces of lighting glass, a conductive layer, and a liquid crystal film. When powered, the liquid crystal molecules align in an orderly manner, allowing light to pass through, making the lighting glass transparent. When powered off, the liquid crystal molecules scatter light in a disordered manner, making the lighting glass translucent. This technology is suitable for applications requiring both privacy and light adjustment, such as bathroom lighting and office partition lighting, allowing users to switch between light transmission modes as needed.
Photochromic coatings automatically adjust their transmittance based on light intensity. This principle is based on the reversible structural changes of photosensitive molecules (such as spiropyran and fulgide) within the coating under ultraviolet light, which alters their absorption of visible light. For example, in the absence of light, the coating is transparent and has high transmittance. Under strong light, the coating darkens in color and decreases in transmittance, effectively protecting against direct sunlight. This coating is suitable for outdoor lighting or indoor lighting exposed to direct sunlight, such as garden and balcony lights. It automatically adapts to changes in ambient light, extending the lifespan of the lighting.
Electrochromic coatings achieve continuous transmittance adjustment through electric field-driven operation. Their core principle is the electrochemical redox reaction of inorganic metal oxides (such as tungsten oxide and nickel oxide). Under the influence of an applied electric field, ions migrate between the anode and cathode, causing the electrochromic material to change its valence state, resulting in a corresponding change in color and dynamically adjustable transmittance. This coating is suitable for high-end smart lighting fixtures, such as dimmable chandeliers in conference rooms and hotel lobbies. Users can precisely adjust light transmittance via a mobile app or smart control system to meet the lighting needs of different scenarios.
Multi-layer composite coating technology achieves comprehensive performance improvements by stacking coatings with different functions. For example, combining an anti-reflective coating with a dimming coating can not only improve basic light transmittance but also enable dynamic adjustment. Or combining a diffuse reflective coating with a photochromic coating can enable lighting fixtures to switch between soft light and automatic dimming. This technology is suitable for lighting designs in complex settings, such as art installations and themed landscape lighting, balancing aesthetics and functionality.
From an industry perspective, the choice of coating technology requires a comprehensive consideration of the lighting type, usage scenario, and cost. For example, residential lighting fixtures prioritize uniform light transmittance and decorative effects, often using diffuse reflective coatings or multi-layer composite coatings. Commercial lighting fixtures emphasize intelligent control and energy conservation, often using dimming coatings or electrochromic coatings. Outdoor lighting fixtures need to adapt to environmental changes, making photochromic coatings more suitable. With the advancement of materials science and optical technology, coating technology is developing towards high precision, multi-function and environmental protection, providing more abundant solutions for adjusting the transmittance of lighting glass.
