Langfang Danmei security equipment Co., Ltd.
Langfang Danmei security equipment Co., Ltd.
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BTLY-I Red barrier filter glasses
BTLY-II Orange barrier filter glasses
BTLY-III Yellow barrier filter glasses
Purpose
Illuminate the evidence with the monochromatic light of the multi-band light source and observe the fluorescence of the evidence through the barrier filter
Structural material
| Color | Red/Orange/Yellow |
| Material of frame | plastic spectacle frame |
| Material of filters | glass-absorption longwave-pass filters |
Working principle
A. The monochromatic light output by multi-band light source is called excitation light. Illuminate the evidence with excitation light, part of the excitation light is reflected by the evidence, and part of the excitation light is absorbed by the evidence. After absorbing the energy of the excitation light, the evidence will release fluorescence. Since the fluorescence released by the evidence is much weaker than the excitation light reflected by the evidence, the fluorescence is invisible when observed directly.
B. The barrier filter goggles use long-wavelength pass filter, which blocks light shorter than a specific wavelength and transmits light longer than a specific wavelength. This specific wavelength is called the cutoff wavelength. The wavelength of the fluorescence is longer than that of the excitation light. When the cut-off wavelength of the barrier filter goggles is longer than that of the excitation light and shorter than the fluorescence's wavelength, the fluorescence of the evidence can be seen.
Technical parameter
Red block wavelength shorter than 560nm and transmits wavelength longer than 580nm;
Orange block wavelength shorter than 520nm and transmits wavelength longer than 540nm;
Yellow block wavelength shorter than 440nm and transmits wavelength longer than 460nm.
Application areas for our products include crime scene investigation, fingerprint collection and development, footprint collection and development, tool marks collection, trace evidence collection, documents examination, forensic medical examination, forensic evidence collection, DNA collection, DNA disinfection, criminal photography, criminal investigation light source, narcotic drugs test, poison test, evidence packaging, evidence marking, crime scene plotting, crime scene protection, human body protection on crime scene.
Our Service
We can provide reliable product and service for you.
1. Q: Is it a reliable company?
A: Beijing Bulant Police Equipment Co.,Ltd. is a company specialized in forensic product, such as: crime scene investigation, trace detection, fingerprint development and extraction, footprint extraction, micro-evidence extraction, files & documents inspection, gunshots detection, forensic examine, DNA extraction, criminal photograph, forensic light source, alcohol test, traffic scene investigation, drug & poison examine, evidence packaging, consumables in lab, etc.
2. Q: What about the delivery?
A: We can offer the door to door services by air or by sea just depend on your actual request. Such as DHL, UPS, TNT, FEDEX…
3. Q: What is the package?
A: Aluminum alloy case/carton case/wooden case.
4. Q: Do you have any timely technology supports?
A: We have a professional technology supporting team for your timely services. We prepare the technical documents for you, also you can contact us by telephone, webcam, online chat (google talk, MSN, skype, yahoo).
5. Q: What is the payment method?
A: T/T, WESTERN UNION, MONEY GRAM, ESCROW, PAYPAL
6. Q: Do you take part in the world exhibition every year?
A: Yes, we took part in exhibitions every year since 2008.