Optical glasses and filter configuration elements: CSS special optical filter glasses one pair 490nm special optical filter glasses one pair CSS special optical filter one slice 490nm special optical filter one slice 415nm special optical filter glasses one pair 415nm special optical filter one slice 450nm special optical filter glasses one pair 450nm special optical filter one slice 510nm special optical filter glasses one pair 510nm special optical filter one slice 530nm special optical filter glasses one pair 530nm special optical filter one slice 470nm special optical filter glasses one pair 470nm special optical filter one slice 555nm special optical filter glasses one pair 555nm special optical filter one slice I. operational principle of multi-band light source Multi-band light source has two functions: first, emit the light to excite the fluorescence of evidence; second, physical evidence and background contrast will change by using different wavelengths of light to irradiate the evidence. Exciting fluorescence of evidence is the main function of multi-band light source. By using the excitation light of multi-band light source to irradiate the physical evidence, the evidence absorbs some of the energy of the excitation light, then longer wavelength light is released, which is fluorescent. The brightness of the fluorescence is much lower than that of the irradiation light. So it cannot be seen by the naked eyes. Multi-band light source has a wide band-pass spectrum, tens of nanometers (as shown in the figure below, BP490). The wavelength of fluorescence is longer than that of irradiation light. The long wavelength filter lets the light of long wavelength pass while block the short which is shorter than a specific wavelength λ (as shown in the figure below, the LP530). Selecting the appropriate filter to block the irradiation light in front of eyes, the fluorescence of physical evidence can be observed with human eyes. II, the factors affecting the fluorescence intensity 1, The higher the intensity of the irradiation light, the higher the luminance of the phosphor. 2, In the circumstances of effectively blocking the irradiation light, the observed fluorescence intensity is higher when the cutoff point of the long-wave pass filter is closer to the end wavelength of irradiation light. The measurement is simple: determine the two points of spectral curves of irradiation light and long-pass wavelength, respectively. The distance between two points is called the matching coefficient D, the smaller the D value, the higher the brightness of the fluorescence. 3, The experimental results show that the matching coefficient D can be controlled within the range of 40nm. In order to get the best fluorescent effect, the relationship between irradiating light and long pass filter must meet this condition. If the matching coefficient D is too large, some fluorescent will be blocked by the long-pass filter. III, the problems of traditional multi-band light sources The bands used by multi-band light source to excite fluorescence: 365nm UV light and dozens of visible wave bands within 400nm-570nm. The wavelength longer than 570nm to excite fluorescence belongs to the far red and infrared regions, and the fluorescence is too weak to be observed by naked eyes. Corresponding to the dozens of the irradiation light, the general multi-band light source is equipped with only red, orange, and yellow long-pass filters. The matching coefficient D of some of the irradiation light wavelengths with the value of the long-wave pass filter will be much greater than 40nm, and some fluorescence will be blocked by the long-pass filter. IV, BT400 characteristics 1, BT400 outputs twelve bands: white, 365nm, CSS, 415nm, 450nm, 470nm, 490nm, 510nm, 530nm, 555nm, 590nm, 610nm. 2, Based on the principle of matching coefficient D is less than 40nm, for CSS, 415nm, 450nm, 470nm, 490nm, 510nm, 530nm, and 555nm, total eight bands, each is equipped with a special long-wave band pass filter and a long-pass glasses. So the ability of exciting fluorescence of each band is greatly enhanced. 3, BT400 is 400W Xenon lamp bulb, and the light intensity of each band is very high, exciting high intensity fluorescence. V, the technical parameters bulb Philips 400-watt xenon lamp AC power source AC 220v, 50Hz lamp life 5000 hours light pipe length 1.5 m White color temperature 6000K Host size 280 x 190 x 150mm White light intensity 10000lux with spot Φ60cm Host Weight 4.5kg