485nm Bandpass Filter

485nm light belongs to the blue light spectrum, characterized by high energy, narrow spectral bandwidth, and strong detectability by specific fluorescent materials or photosensitive components;

  • Application 1: In fluorescence microscopy systems, it eliminates extraneous light to precisely capture signals from biological samples labeled with 485nm-excited fluorescent dyes, enhancing imaging clarity and specificity.
  • Application 2: For water quality monitoring devices, it isolates the 485nm wavelength to quantify concentrations of specific pollutants like fluorescent tracers or organic contaminants through targeted spectral analysis.
  • Application 3: In LED optical communication networks, it acts as a spectral purity enhancer, filtering out unwanted noise to ensure stable transmission and accurate reception of 485nm wavelength signals in high-speed data transfer systems.

485nm Filter Selection Guide

1. GFP Labeling Imaging in Fluorescence Microscopy

In fluorescence microscopy, 485nm filters are primarily used to excite fluorescent markers such as enhanced green fluorescent protein (eGFP), which has an excitation peak at 485nm and an emission peak at 507nm. The filter configuration for this application should meet the following requirements:

Filter Configuration Details:

  1. Excitation Filter
  • Specification: Narrowband pass filter with a central wavelength of 485nm and 20nm bandwidth (e.g., 475–495nm range).
  • Performance: Transmittance >90% in the passband, and optical density (OD) >5 in the stopbands below 460nm and above 510nm.
  • Rationale: This precise spectral matching ensures efficient energy transfer to eGFP while suppressing background noise from non-target wavelengths.
  1. Dichroic Mirror
  • Specification: Reflects 485nm excitation light and transmits 507nm emission light, with >95% reflectivity at 485nm and >90% transmittance for wavelengths above 500nm.
  • Rationale: Separates excitation and emission paths to prevent direct excitation light from contaminating the detection channel, thereby enhancing signal purity.
  1. Emission Filter
  • Specification: Bandpass filter with a central wavelength of 520nm and 20nm bandwidth (e.g., 500–540nm range).
  • Performance: Transmittance >90% in the passband, and OD >5 for wavelengths below 485nm.
  • Rationale: Blocks residual excitation light while allowing only eGFP fluorescence to pass through, significantly improving the signal-to-noise ratio (SNR).

Core Value of Selection:

By aligning with eGFP's spectral characteristics, this filter combination addresses key challenges in fluorescent imaging:

  • The narrowband excitation filter reduces non-target excitation light to <0.01% (OD >4), minimizing cross-excitation of background molecules.
  • The high-stop emission filter limits excitation light leakage to <0.01%, ensuring clear visualization of fluorescent structures even in complex biological samples with high auto-fluorescence backgrounds.

2. Machine Vision Structured Light Inspection in High-Temperature Environments

In industrial inspection, 485nm filters are critical for blue structured light 3D measurement systems, especially when analyzing red-hot metal workpieces (e.g., 440–485nm blue light projection gratings). The filter configuration must optimize imaging quality under extreme conditions:

Filter Configuration Details:

  1. Bandpass Filter
  • Specification: Broadband pass filter with a central wavelength of 485nm and 40nm bandwidth (e.g., 465–505nm range).
  • Performance: Transmittance >85% in the passband, and OD >4 for wavelengths below 340nm (UV) and above 540nm (IR).
  • Rationale: Excludes high-temperature thermal radiation (IR >540nm) and UV interference (<340nm), preserving only the blue structured light signal for accurate 3D reconstruction.
  1. Environmental Resistance Coating
  • Specification: Hardened multi-layer dielectric coating (e.g., alternating TiO₂/SiO₂ layers) with:

90% transmittance at 485nm

  • Temperature resistance up to 150°C
  • Enhanced scratch and chemical resistance
  • Rationale: Withstands harsh industrial conditions (dust, oil, temperature fluctuations), ensuring long-term stability and consistent optical performance.

Core Value of Selection:

This configuration solves the critical issue of thermal radiation-induced image distortion in structured light systems:

  • Reduces background IR noise to <0.01% of original intensity, eliminating interference from 1000°C+ heat sources.
  • Maintains blue light signal loss <10%, enabling sub-millimeter 3D measurement accuracy (±0.1mm) even in molten metal environments.
  • The robust coating extends filter service life by 50% compared to standard coatings in dusty or corrosive settings.

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