BTTS-II Portable 12-waveband light source with accurate matched filter

Purpose

A. Excite the fluorescence of many kinds of evidence to discover or develop evidence.

B. The background and evidence have different reflectance for different colors. Illuminate the evidence with different colors of the multi-band light sources, different contrast effects will be shown. Record the best contrast effect.

Feature

A. Shortage of ordinary multi-band light source

Ordinary multi-band light source is only equipped with red, orange, and yellow absorption barrier filter goggles and absorption filters. Match between the absorption filter and the output wavelength:

a. Yellow goggles match well with 415nm.

b. Orange goggles match with 450, 470, 490, 510, CSS; among them, CSS and 510nm have the best match effect with the orange goggles. But it does not match well with other wavelengths, which may lead to bad observation effect of fluorescence.

c. Red goggles can match with 530 and 555, but compared with 530, the match with 555 has better observation effect of fluorescence.

B. Advantages of multi-band light source with exact-match filters

Equipped with 7 sets of barrier filter goggles and absorption filters, corresponding to 8 wavelengths of 415, 450, 470, 490, 510, CSS, 530 and 555. 510 and CSS share an identical set of barrier filter goggles and absorption filters. The barrier filter goggles and the absorption filters are both interferometric longwave-pass filters, which, if accurately matched with the excitation light, can give the best fluorescence excitation effect for each wavelength.

Content

Specifications

A. General parameter

B. Output wavelength and luminous power

C. Reference table of output band, barrier filter goggles and absorption filter

Method of use

A. Built-in battery

a. Install the battery case, and wire the battery case to the light source assembly.

b. Connect the inlet of the light guide with the light outlet of the light source.

c. Switch the power option to "battery", then the light source starts to output light.

d. Rotate the knob to select the output wavelength.

e. Hold the light outlet of the light guide to illuminate the evidence, or fix the light outlet on the support and illuminate the evidence.

f. Wear barrier filter goggles that match the output light to observe the fluorescence.

g. Select the absorption filter that matches the output light and install it in front of the lens to photograph the fluorescent image.

B. AC power supply

a. Wire the AC power to the light source assembly.

b. Connect the inlet of the light guide with the light outlet of the light source.

c. Switch the power option to "AC", then the light source starts to output light.

d. Rotate the knob to select the output wavelength.

e. Hold the light outlet of the light guide to illuminate the evidence, or fix the light outlet on the support and illuminate the evidence.

f. Wear barrier filter goggles that match the output light to observe the fluorescence.

g.Select the absorption filter that matches the output light and install it in front of the lens to photograph the fluorescent image.

Application scope

A. Color separation illumination to improve trace contrast

a. Method: the multi-band light source can output different colors of light, including red, orange, yellow, cyan, blue and violet. Illuminate the trace with different colors of light. Since the trace and the background have different absorption rates for monochromatic light, the contrast between the trace and the background will change with the change of light. Choose the best contrast effect for photography.

b. Special band 415nm: The absorption peak of bloodstains is 415nm. Illuminating bloodstains with 415nm light can deepen the bloodstains color, which is quite effective for developing latent bloodstains on the light surface. Method: illuminate the evidence with 415nm light and white light alternately, and observe the nuance between the two.

c. Special band 580nm: The absorption peak of fingerprint developed by ninhydrin is 580nm. Illuminating the fingerprint with 580nm light can deepen the bloodstains color, which is quite effective for developing latent fingerprint on the light surface.

B. Excitation of evidence fluorescence

a. Working principle of fluorescence excitation by multi-band light source

a) Illuminate the evidence with the excitation light from the multi-band light source. The evidence transfers part of the excitation light it absorbs into light with longer wavelength, which is fluorescence.

b) Choose a suitable absorption filter and view the evidence through the absorption filter. The absorption filter blocks the excitation light but allows the fluorescence to pass through, so the fluorescence of the evidence can be seen.

c) Part of the excitation light that passes through the absorption filter will interfere with the fluorescence effect.

d) If the absorption filter blocks part of the fluorescence, the observed fluorescence intensity will decrease.

b. Working principle of multi-band light source with exact-match filters

The multi-band light source with exact-match filters is equipped with exclusive absorption barrier filter goggles and absorption filters for wavelengths of CSS, 415nm, 450nm, 470nm, 490nm, 510nm, 530nm and 555nm. The absorption barrier filter goggles can match exactly with the excitation filter of the light source. The matching method is as follows:

a) The transmittance at the intersection E between the spectral curve (transmittance-wavelength curve) of the excitation filter and that of the absorption filter is less than 10-4, which ensures that each absorption filter can completely block the excitation light, and there is no passing-through excitation light to interfere with the fluorescence.

b) Find the following points in the figure: point C=transmittance of 50% on the spectral curve of the excitation filter; point D=transmittance of 50% on the spectral curve of the absorption filter. The distance between point C and D of each group of excitation filter and absorption filter is less than 40nm. This ensures that the absorption filter blocks fluorescence as less as possible, so that the observed fluorescence is strong enough.

Figure 1: Match between 530nm excitation filter and interferometric absorption filter

c. Problems with ordinary multi-band light source

Multi-band light source is equipped with eight wavelengths for fluorescence excitation. Ordinary multi-band light source is only equipped with red, orange, and yellow absorption filters. Match between the absorption filter and the output wavelength: yellow goggles with 415; orange goggles with 450, 470, 490, 510, CSS; red goggles with 530 and 555. Among them, the following matches have the best effect: yellow goggles with 415, orange goggles with CSS, red goggles with 555. But for other wavelengths, the distance between point C and D of the excitation filter and the absorption filter is too large, part of the fluorescence will be blocked by the absorption filter, and the intensity of the fluorescence will be weakened.

d. Application scope of excitation of evidence fluorescence of multi-band light source with exact-match filters

e. Application cases of multi-band light source with exact-match filters

Excite the fluorescence of DFO-developed fingerprints with 530nm light. The observed fluorescence is significantly clearer than that of ordinary multi-band light source. The reason is that when the DFO-treated fingerprint is illuminated with the 530nm light of the ordinary light source and observed with red goggles, the red goggles match perfectly with the 555nm light but poorly with the 530nm light. While blocking the excitation light, the red goggles also block much fluorescence, so the observed fluorescence will be reduced significantly.

Fluorescence effect of combination of 510nm pbotostimulate luminescence and 510nm receiving filter

Fluorescence effect of combination of 530nm pbotostimulate luminescence and 530nm receiving filter

Fluorescence effect of combination of 555nm pbotostimulate luminescence and 555nm receiving filter

Product Application

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.