Product Descriptions:
| Characteristics: | 650 & 850nm Dual Bandpass Filter |
| Type: | Interference Type Filter |
| Central Wavelength(in nm): | 650nm, 850nm |
| Peak Transmittance(%) : | >90% |
| Full Width at Half Maximum(FWHM): | 40nm |
| Optical Density (OD): | OD2 – OD3 |
| Shape: | Round, Square, Custom Shape |
| Color: | Light Green |
| Angle of Incidence(AOI): | 0° |
| Surface Quality: | 60/40 scratch-dig |
| Dimension(mm): | Customized, max. 300x300mm |
| Thickness(mm): | 0.21、0.3、0.55、0.7、1.0、1.1、1.5、1.8、2.0、3.0mm…etc. |
| Substrate materials: | Ultra-clear glass,K9,BK7,B270,D2637T, Quartz Glass(Fused Silica) or other specified. |
| Remark: Support customized for wavelength from 200-2500nm. | |
Measured Spectral Graph – 650 & 850nm Dual Bandpass filter:
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| Picture 1: 650 & 850nm Dual Bandpass Filters Spectral Graph measurement |
What is 650 & 850nm Dual Bandpass Filter?
A 650 & 850nm Dual Bandpass Filter is an optical filter to allow red light passing at around 650nm and near-infrared light around 850nm, making it a key optical component in day and night cameras.
What is the difference between a dual bandpass filter and a standard (single) bandpass filter?
The main difference between a dual bandpass filter and a standard (single) bandpass filter is that a standard bandpass filter focuses on a single specific spectral passband, while a dual bandpass filter integrates two spectral channels into a single optical component.
What is typical application for 650 & 850nm Dual Bandpass Filters?
Firstly, the typical application for 650 & 850nm dual bandpass filters are in security and surveillance cameras, and it passes red light for accurate daytime color imaging while the 850nm band transmits IR illumination for clear nighttime monochrome video. Additionally, traffic systems also use these filters for license plate recognition and red-light enforcement, along with machine vision and trail cameras.
What is key parameter when choose for right Dual Bandpass Filters?
When selecting a Dual Bandpass Filter, normally the following factors need to be taken into consideration：
- Central Wavelength (CWL)：Firstly, CWL is one of key parameter to designate, it refer to the central wavelength at stable high transmission rate passband.
- Peak or Average Transmittance: typically ≥90%, Higher transmittance might need Anti-reflective(AR) coating.
- Full width at half maximum (FWHM): it refer to the interval between the two wavelength points where the transmittance rate reaches 50%.
- Blocking rate: usually in terms of optical density(OD), OD2-OD3 for standard and higher will be OD4-OD6 per requirement.
- Angle of Incidence (AOI): AOI need to be considered as Interference Filter is angle sensitive, 0° AOI by default, other AOI e.g. 30/45° need to be specified.
- Physical and environmental requirement: Substrate type, dimensions and thickness, surface quality, and environmental durability.
Shenzhen Hengda Liyuan Optoelectronics introduced advanced optical technology that apply depositing nano-materials through ion-assisted evaporation onto a multilayer hard film in a high vacuum environment which coating layer is firm and has good tightness, and small bandwidth drift. Besides, Liyuan optoelectronics have been focus on optical coating for more than 17 years ,and the company offer one-stop optical filters solution including Narrow Bandpass Filters, IR cut-off Filters, Longpass & Short Filters, Notch Filters, ND filters, Star filters and Optical sapphire block.
