Minus Blue Illumination Filter

Add versatile Keyence fluorescence capability with the NIGHTSEA adapter system

The NIGHTSEA Model SFA Fluorescence Adapter system adds a versatile fluorescence imaging capability to the Keyence VHX series of digital microscopes. A growing number of Keyence owners are using the system successfully for a variety of applications. Visit our gallery of images made with the NIGHTSEA adapter and the Keyence microscope.

Fluorescence solutions for most Keyence lenses

Our adaptations to the Keyence system are concerned with the lens, not the microscope model (VHX-5000, -6000, etc.). We offer variants of our fluorescence adapter system that work with the most commonly used Keyence lenses – the VH-Z00, -Z20, -Z50, -Z100, -ZST, and with two of the lenses incorporated in the VHX-7100 Fully Integrated head (VHX-E20 and -E100).

The key elements of any fluorescence system are

  • a light source that produces sufficient energy in the appropriate wavelength range to excite fluorescence in the sample of interest
  • a barrier filter in the viewing path that blocks reflected excitation light while transmitting the fluorescence emitted by the sample

NIGHTSEA implements these for the Keyence system with

  • high intensity LED light sources available in five excitation wavelength ranges (see list further down page)
  • emission barrier filters that can be added to the Keyence lenses easily and non-invasively

The components of a NIGHTSEA system that adds a single excitation/emission wavelength combination on a Keyence microscope are:

  • Flexible gooseneck lamp base with LED drive circuit and intensity control;
  • Universal power supply (120/240VAC, 50/60Hz) with international plug set
  • Excitation light source
  • Emission barrier filter
  • Barrier filter glasses for fluorescence viewing and eye safety
  • Padded carrying case

Additional wavelength sets are implemented by adding a matched set (light plus filter set) consisting of a light source, barrier filter, and filter glasses.

Lens-specific solutions

The implementation approaches for the supported Keyence lenses are summarized here

  • VHX-7100 Fully Integrated (FI) Head
    • VHX-E20 and -E100
      • Light source – placed to the side of the microscope stage
      • Barrier filter – inserts in the Analyzer slot at the right side of the FI head
    • VHX-E500 and -E2500
      • Use with these lenses is likely not practical due to short working distance

Comprehensive solution kit

We have configured Keyence fluorescence adapter kits that include the three most useful excitation wavelengths for varied industry applications, and that are suited to various combinations of the supported Keyence lenses. The kit price is significantly less than purchasing the items separately.

Each Industry Kit includes the following items, or a subset that is suited to the particular Keyence lenses you want to outfit:

  • Three excitation light heads – Ultraviolet (UV), Violet (VI), and Royal Blue (RB)
    • This recommendation is based on our experience with varied applications.
  • Three barrier filters, of one or more types depending on the lens(es) to be supported
  • Matching barrier filter glasses for each excitation wavelength
  • Accessory hardware for mounting the NIGHTSEA light head over the VH-ZST fiber optic input port (enhanced performance at high magnification)*
  • Gooseneck lamp base with dimming control
  • Universal power supply – 120/240VAC, 50/60Hz, with international plug set
  • Packing/carrying case with custom-cut foam

*Only included with systems that support the VH-ZST lens

Why we recommend a set of three excitation wavelengths for industry needs

We have found that the combination of the Ultraviolet, Violet, and Royal Blue excitation/emission sets addresses a wide variety of industrial imaging challenges. The most common misconception we encounter is that fluorescence is uniquely associated with ultraviolet (UV) light and many customers immediately ask for that wavelength. However we have found in several cases – even some in which UV was specifically recommended by a dye manufacturer – that either Violet or Royal Blue provided superior performance. For example

  • A prospective customer wanted to image concrete thin sections impregnated with fluorescent dye. The dye supplier recommended UV, and it is true that UV will make the dye fluoresce nicely. We found that our Royal Blue excitation produced significantly brighter fluorescence.
  • Similar to above, except that a fluorescence epoxy had been used to highlight surface cracks in a test sample. Royal Blue excitation yielded brighter fluorescence.
  • A prospective customer sent us a sample of material that was known to fluoresce under UV. The goal was to see the distribution of non-fluorescent particles in a fluorescent matrix. While both UV and Royal Blue excited fluorescence in the sample, the best imaging contrast was achieved with Violet excitation.
  • We achieve enhanced performance with the ZST lens by mounting the light head on the lens' fiber optic port, but that path does not transmit UV well. In many cases, for example to inspect conformal coating, Violet is an excellent alternative to UV.

Acquiring the three-color system will provide the highest chance of success and will equip you with a versatile toolkit to address new fluorescence imaging challenges as they arise. Contact us if you would like to discuss your application further.

Performance expectations

The microscopes in the Keyence VHX series were not designed for fluorescence. That said, the NIGHTSEA adapter system adds a fluorescence capability that is proving to be valuable for a growing number of users. Several companies have purchased multiple adapters so that they could replicate the performance across multiple microscopes. In at least one case the customer only purchased their Keyence system because of the added NIGHTSEA fluorescence capability that enabled a critical analysis function for them.

Wavelength sets

There are five excitation/emission wavelength combinations available for the system.

Color Designation Excitation Emission
Ultraviolet UV 360 - 380 nm 415 nm longpass
Violet VI 400 - 415 nm 450 nm longpass
Royal Blue RB 440 - 460 nm 500 nm longpass
Cyan CY 490 - 515 nm 550 nm longpass
Green GR 510 - 540 nm 600 nm longpass

Enhanced performance with the VH-ZST

Pack: Each