Home » IR640, 640nm Infrared cut-off filter for fluorescence microscopy, machine vision, biomedical testing

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IR640, 640nm Infrared cut-off filter for fluorescence microscopy, machine vision, biomedical testing

Product features

● Narrow transition zone slope less than 20nm transmission

● High transmittance over 92% or higher

● Deep cut-off depth and infrared light blocking

●Multiple substrates available

●Support Customization for cut-off wavelengths

Product Detail

Product Descriptions：

Characteristics:	640nm IR Cut-Off Filter
Type:	Interference type filter
Cut-off Wavelength(in nm):	640 nm
Average Transmittance(%) :	>95%(with AR coating) >92%(with deep blocking)
Optical Density (OD):	OD2
Color:	Blue
Surface Quality:	60/40 scratch-dig
Dimension(mm):	Standard for 86x86mm, 80x80mm, other can customized, max. 300x300mm
Thickness(mm):	Available: 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:380-1100nm

Spectral graph measurement

Picture 1: IR640nm + AR Spectral measurement graph

Picture 2: IR640nm spectral measurement graph

What is the 640nm IR Cut-Off Filter?

A 640nm IR cut-off filter, also called IR640 Filter is a type of short wavelength pass filter, which core function is to efficiently transmit visible light below 640nm while blocking or reflecting near-infrared light above 640nm. Particularly,The average transmittance of IR640 with Anti-reflective (AR) coating can reach above 95%.

What is typical application for the 640nm IR Cut-Off Filters?

The 640nm IR Cut-Off Filters find extensive application across various fields:

Fluorescence microscopy imaging: transmits excitation or emission fluorescence, blocks stray light & autofluorescence, improves signal-to-noise ratio.
Machine vision and industrial inspection: with blue or green illumination, rejects ambient IR, ensures visible-only imaging, boosts accuracy.
Precision spectroscopic analysis: isolates visible from NIR band, eliminates detector crosstalk, ensures spectral purity.
Biomedical testing: employed in devices such as pulse oximeters and flow cytometers to define the signal acquisition spectral range, ensuring data accuracy and measurement reliability.
Laser systems and optical communications: used to filter out pump light or stray infrared light, protecting optical components and improving system signal-to-noise ratio.
Security surveillance and night vision systems: used with fill lights to effectively suppress infrared interference in visible-light imaging mode, restoring true color reproduction.

What is key parameter when choose for suitable IR cut-off Filter?

When selecting IR cut-off filters, normally the following factors need to be taken into consideration：

Cut-off Wavelength: refers to the designated intermediated wavelength (e.g. 650nm) at transition from transmission to reflective zone, and measure at 50% transmittance.
Peak or Average Transmittance(in %): typically ≥90%, Higher transmittance might need Anti-reflective(AR) coating.
Blocking rate: usually in terms of optical density(OD), OD2-OD3 for standard and higher blocking rate 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.

Related products:

IR650 , 650nm Infrared cut-off Filter, Lens 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: Because the interference type filter varies its performance at different angles, the spectral parameters usually determine its appearance color; moreover, the pictures in this link may originate from various shooting angles, so the actual color should therefore rely on the final spectral parameters required as the standard.