Research Of Light Source System Design For The Adjustable Red-blue Associative Photodynamic Therapeutic Equipment

With the development of semiconductor technology, LED products withhigh-performance have extended to all walks of life gradually. The application of all-bandLED in the field of biomedical is becoming one of the most popular research topic，especially the photodynamic light therapy with LEDs used as light source, which is therelatively new treatment in the field of dermatology phototherapy, as well as a hot research.This method takes use of the characteristics of LEDs, such as green, environmental friendly,operated at low voltage, long life and cold light source, which can achieve light medicalmore efficiently, safely, and with no side effects. However, the power of LEDs is small andthe light extraction efficiency is poor, which means that the LEDs chip array is essential tothe application of LEDs in the field of medical. Therefore, a reasonable and effective opticaldesign is significantly meaningful to the promotion of the LED products’ application. Thispaper mainly researched the secondary optical design of LED optical system base on thetheory of nonimaging optics, and combined with the corresponding design of LED driver,then implementation the preparation of entity model for LED photodynamic therapeuticequipment, to meet the basic requirements of the treatment for facial skin disease. The maincontent and its achievements of this paper are as follows:Firstly, the secondary optical design of LED point light source was studied in this paper.Based on the demand of achieveing a uniform illumination sent from a point light source,related optical lens have been designed. Then the spatial distributions of intensity andillumination have been analyzed by using the optical simulation software Tracepro, andfinally achieve the LED point light source which can meet the require of intensity,illumination and the uniform of illumination by several feedback optimization design.Secondly, the optical design of photodynamic therapeutic equipment has beeninvestigated, and the free surface optical design scheme has been put forward creatively tosimulate the model of free surface of light source. After several rounds of feedback design,the design requirements of photodynamic for facial skin with dose of3.3J/cm2and theillumination uniformity up to80%have been achieved.Finally, the circuit design of a light therapy device has been investigated. Aiming at theoutput power and working conditins of630nm LED and415nm LED are different from each other, and also phototherapy require the instruments to meet certain power intensity, mode(continuous or pulsed) and time adjustable functions. In this paper, the off-line buck circuithas been used, and two-way adjustable and controllable have been achieved. By optimizingthe thermal structure of the slab model, the system operating temperature has been reduced.