Product Descriptions:
| Characteristics: | 640nm Bandpass Filter |
| Type: | Interference type |
| Central Wavelength (CWL): | 640+-5nm |
| Full Width at Half Maximum(FWHM): | 20nm |
| Peak Transmittance(%) : | >90% |
| Surface Quality: | 60/40 scratch-dig |
| Optical Density (OD): | OD2 |
| Color: | Red |
| Shape： | Round or customized. |
| 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: | Ultra-clear glass,K9,BK7,B270,D2637T, Quartz Glass(Fused Silica) or other specified. |
| Remark：Support customized for wavelength from 200-2000nm. | |
Measured Spectral Graph – 640nm Bandpass filter:
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| Picture 1: BP640-20nm Spectral Graph measurement |
What is typical application for 640nm Bandpass Filters?
A 640 nm bandpass filter is a specialized optical component that only transmits light within a narrow wavelength band centered at 640nm, while blocking all light outside this range. Typical application for 640nm bandpass filter is very broad, including biomedical fluorescence detection, biological microscopy and flow cytometry to select red fluorescence signals. It also serves for color imaging, LED spectral purification, optical sensing, industrial photoelectric detection and scientific spectroscopy, effectively filtering out stray light and improving signal purity and detection accuracy.
What are key parameters when choose for a suitable infrared bandpass filter?
When selecting a Narrow Bandpass Filter, normally the following factors need to be taken into consideration：
- Central Wavelength (CWL)：CWL is one of key parameter to designate first, 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): FWHM 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 vacuum 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 Filters, Shortpass Filters, Notch Filters, ND filters, Star filters and Optical sapphire block.
Remark：The appearance color of the optical filter is usually determined by the spectral parameters, the interference type filter varies at different angles, and the pictures in this link may have been taken from different angles, so the actual color should be based on the final spectral parameters required！
