Design And Evaluation Of UV-LED For Topical Fluorescence Examination

Surface fluorescence detection is an important way to diagnosis of skin diseases.We identify kinds of skin diseases through the UV light source excite fluorescence characteristics.At present,a lot of UV light source for surface fluorescence detection is gas source,the light radiation intensity of illumination is not homogeneous,adjustable.With the development of semiconductor technology,UV LED light source is used tomedical and biological factors because of its high luminous efficiency,long life.But requirements for UV LED light source is different in different occasions.at present,UV LED light is design for Curing and disinfection,there are few design in surface fluorescence detection.This article analyzed the process of surface fluorescence detection.I design a UV light source for surface fluorescence detection according to the demand.This design includes two kinds of LED light source,one kind is UV LED used for fluorescence excitation,the other is the white LED of color temperature of 6500 k used for general lighting.In order to adapt to different surface fluorescence detection environment,the brightness of the white LED and radiation intensity of UV LED array is adjustable.And white light intensity and ultraviolet radiation intensity of illumination should be uniformity.To meet the above requirements,this article includes three following parts:Current drive circuit design,this paper use two LM3404HV driver chip as the core decompression conversion circuit.9V input voltage is drop respectively to UV LED arrays and white LED of the work of the rated voltage.it provide LED with stable,reliable electric current.Control system design,this article use STC89C52 single-chip microcomputer control chip as the core,and adopts the PWM dimming method.The 52 microcontroller output PWM wave.I use PWM wave to control LM3404HV driver chip to control the radiation intensity of UV LED array and brightness of white LED.I use independent key keyboard as input signal,and using digital tube to display the current LED brightness level.Optical system design,this article studies the secondary design of LED point light source.By optimizing the arrangement of the UV LED array,makes close target surface to get uniform radiation.In order to further improve the light LED uniformity and efficiency,I design parabolic reflector.I use the optical design software tracepro to analysis intensity distribution of the sample surface and radiation distribution.making the light intensity,the intensity of illumination and the radiation intensity of illumination distribution reaches the design requirements by using feedback result to optimizate design.Finally,measuring the parameters of UV light source system,including the stability of light source,adjustable,uniformity.Then using UV light source system on the photosensitizer fluorescence detection application testing compared with wood lamp.