Product Descriptions
| Characteristics: | 640nm Longpass filter |
| Type: | Interference type |
| Cut-off Wavelength (nm): | 640nm |
| Average Transmittance(%): | >95% |
| Optical Density： | OD2-OD3 |
| Surface Quality: | 60/40 scratch-dig |
| Color: | Red |
| Shape: | Round or customized. |
| Dimension: | Customized, max. 300x300mm |
| Thickness: | 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: Spectral range:350-1800nm | |
Measured spectral graph
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Picture 1: LP640nm Spectral measurement graph |
What is typical application for 640nm longpass filter?
A 640nm longpass Filter is an optical component that transmits light with wavelengths longer than 640nm while blocking or cutting off light with wavelengths shorter than 640nm.
Most commonly, the 640nm LP Filters are widely used in beauty and medical devices , especially for beauty instruments such as laser hair removal machines and skin rejuvenation devices, they filter out harmful ultraviolet and short-wavelength light while selectively transmitting the 640nm–1200nm spectral band to achieve effects like hair removal and skin rejuvenation. Besides, In analytical instruments such as fluorescence microscopes and spectrometers, they serve as emission filters, allowing specific wavelengths of fluorescence to pass through. Additionally, they are applied in fields such as machine vision and industrial inspection, forensic detection, and defense and scientific research.
What is key parameter when choose for suitable Longpass filter?
When selecting a Longpass Filter, normally the following factors need to be taken into consideration：
- Cut-Off Wavelength: it is one of the most important parameters, typically defined as the wavelength transmittance at 50% .
- Average or Peak transmittance: usually average transmittance ≥90%, higher transmittance e.g. 92% or 95% on average or specific single point need to definite and communicate with manufacturer, higher transmittance need to additional AR coating.
- Blocking rate: usually expressed 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 consider 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.
Related products:
LP600, 600nm Longpass Filter, Support Customized
650nm Longpass Filter,LP650nm Long-wavelength pass Filter,Support customized
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！
