LP690 롱패스 필터(T>90%@700-1100nm, OD2@350-680nm)

Far-Red/NIR Fluorescence Imaging

This is the most common scientific application for an LP690 filter. It is used as an Emission Filter to block excitation light and pass the fluorescence signal from far-red fluorophores.

• Function: The filter blocks the visible excitation light (OD2 @ 350-680nm) while transmitting the longer-wavelength fluorescence emitted by the sample (T>90% @ 700-1100nm).
• Target Fluorophores: Dyes and proteins that fluoresce in the Near-Infrared (NIR) window, such as E2-Crimson, Cy5.5, Alexa Fluor 680, or 700, and IR-Dye 700.

Recommended Light Sources (Excitation)

• LEDs: High-power LEDs with peak wavelengths in the Orange to Deep Red range (e.g., 590nm, 630nm, or 660nm). The filter effectively blocks this source light from reaching the sensor.
• Lasers: 633nm HeNe lasers or 635-660nm diode lasers.

Machine Vision & Surveillance (NIR Imaging)

In industrial or security settings, this filter is used to remove visible light noise and strictly image in the Near-Infrared spectrum.

• Function: It blocks visible ambient light (sunlight glare, overhead room lighting) which can cause variable contrast, and only accepts controlled NIR illumination.
• Use Cases: Optical Character Recognition (OCR) on colored packaging, inspection of produce (bruise detection often requires NIR), and night-vision surveillance.

Recommended Light Sources (Illumination)

• NIR LEDs: The light source must emit in the filter's passband. Recommended peaks are 730nm, 850nm, or 940nm.
• Broadband IR Illuminators: Tungsten or Halogen lamps can be used if they are filtered or if the heat/broad spectrum is acceptable.