Visible and infrared light are frequently present in the light source signal. A cold/hot mirror is a dichroic filter optical element that separates visible light from infrared light and collects only visible light in order to prevent infrared radiation-induced system heating. Alfa Chemistry can provide a typical cold/heat reflector coating with a high-quality multilayer dielectric film for your glass substrate surface. Reflectors with our standard coating return infrared radiation to the light source rather than absorbing it as a filter, so they don't grow hot. Before it enters the optical system, thermal energy is successfully prevented and reflected.
Applications and Benefits of Protected Silver Mirror Coating
In the visible spectrum, thermal reflector coatings have a high transmittance and a high reflectance in the near infrared spectrum. Our multi-layer dielectric coating on thermal mirrors effectively reduces heat, reducing the influence on optical system performance. It also has a stronger and more neutral optical transmission of visible light, as well as a substantially more effective thermal radiation reflection in the near-infrared region. Infrared cut-off filters for camera chips, infrared reflective optics in lighting systems, measurement and sensor technology, and lighting applications in the automobile industry are all examples of where the coating is used.
Fig 1. Software predicted (a) transmittance spectra and (b) reflectance spectra of TiO2/Cu/TiO2 THR with different thickness of Cu layer ranging from 10 nm to 40 nm and fixed thickness of TiO2. (c) shows average transmittance in wavelengths ranging from 400 to 700 nm and average reflectance in the wavelengths ranging from 700 to 1000 nm. (d) Schematic diagram of transparent heat reflector (THR) using symmetrical dielectric (TiO2) and identical thickness over and below Cu layer. (Dalapati G. K, et al. 2016)
High reflectivity in the visible range and high transmission in the near infrared wavelengths characterize the spectral features of cold mirror coatings. With our typical coatings, cold mirrors give excellent optical reflection in the visible wavelength range and great transmission in the infrared area, with over 90% transmission. They're perfect for eliminating heat and extracting cold visible light from the beam path while keeping image quality. Cold mirrors in lighting systems, sensor technologies, highly reflecting mirrors, medical lighting equipment, and heat dissipation filters in optical systems all benefit from the coatings.
Alfa Chemistry Standard Optical Coating
In the visible spectrum, thermal reflector coatings have a high transmittance and a high reflectance in the near infrared spectrum. Our multi-layer dielectric coating on thermal mirrors effectively reduces heat, reducing the influence on optical system performance. It also has a stronger and more neutral optical transmission of visible light, as well as a substantially more effective thermal radiation reflection in the near-infrared region. Infrared cut-off filters for camera chips, infrared reflective optics in lighting systems, measurement and sensor technology, and lighting applications in the automobile industry are all examples of where the coating is used.
| Surface Roughness | 4 - 6λ |
| Coating Construction | Designed for 0° angle of incidence
Fully dielectric, multi-layer filter coating
Custom cut-off wavelengths and cut-off wavelengths upon request |
| Visible Transmittance | Tavg＞90%@425-675nm |
| Visible Reflectance | Ravg＞95%@750-1150nm |
| Optical Flatness | Depending on glass thickness; Defined flatness per inquiry |
| Standards | Abrasion MIL-C-675 C tape test
Abrasion resistance according to MIL-M-13508 C |
High reflectivity in the visible range and high transmission in the near infrared wavelengths characterize the spectral features of cold mirror coatings. With our typical coatings, cold mirrors give excellent optical reflection in the visible wavelength range and great transmission in the infrared area, with over 90% transmission. They're perfect for eliminating heat and extracting cold visible light from the beam path while keeping image quality. Cold mirrors in lighting systems, sensor technologies, highly reflecting mirrors, medical lighting equipment, and heat dissipation filters in optical systems all benefit from the coatings.
| Surface Roughness | 4 - 6λ |
| Wavelength Range | 425 - 1200 nm |
| Coating Construction | Metal-free 100% dielectric layers |
| Visible Transmittance | Ravg＞95%@425-675nm |
| Visible Reflectance | Tavg＞90%@750-1150nm |
| Optical Flatness | Depending on substrate material and thickness |
| Standard Glass Thicknesses | 1.00 mm ± 0.10 |
| Standards | Abrasion MIL-C-675 C tape test
Abrasion resistance according to MIL-M-13508 C |
Reference
- Dalapati G. K, et al. (2016). "Color Tunable Low Cost Transparent Heat Reflector Using Copper and Titanium Oxide for Energy Saving Application." Scientific Reports. 6: 20182.
