The theoretical, design, technological and software aspects of creating a dynamically controlled LED surgical lamp for contrast visualization of biological tissues during surgical operations are considered. The concept of design a surgical lamp, which combines white light illumination and dynamic control colored illumination, is proposed. It allowed both to reach high-quality illumination of the operational field and to improve the contrast of visualization of different biological tissues and objects. An optical system of the lamp, which allows achieving maximum and uniform illumination and provides uniform color mixing all over the operating field, is considered. Surgical lamp used both phosphor-conversion white LEDs for general illumination and monochrome AlInGaN, AlGaInP LEDs for precision control of color illumination. The developed software allows you to independently change the intensity of six spectral LED components: blue (460 nm), cian (505 nm), green (530 nm), lime (550 nm), orange (590 nm) and red (630 nm) to synthesize colored lighting in wide chromaticity scale. Also, within a wide range, it is possible to change the luminance and color temperature of the general illumination from white phosphor LEDs. Color and luminance evels are controlled by pulse-width modulation of the LED current. The light parameters of the surgical lamp are set by remote computer connected to the lamp via Bluetooth. To determine optimum illumination conditions for contrast visualization, optical characteristics of different biological tissues in combination with color LED emission are investigated. As a result, the experiments on animals showed the contrast of biological tissues imaging increases when they were illuminated with specially selected spectra emitted by developed lamp.
To determine optimal lighting conditions for contrast imaging of surgical objects, optical characteristics of biological tissues and spectral characteristics of smart light "LED light" source based on RGBW LED are compared. The spectral characteristics of tissues and organs have been investigated. Optimal lighting conditions for contrast imaging of biological tissues during surgery were studied. The optimal colour of light for working with individual organs against the background of the whole organism is selected. Perspective of light fixture application with the possibility of dynamic colour control is shown.
This paper presents a comprehensive analysis of the electroluminescence (EL) and current distributions in connection with heat transfer (thermal resistance) in high-power “vertical" and "face-up" AlGaInN light emitting diodes (LEDs). The study was carried out using a combination of high-resolution EL mapping techniques giving information on the lateral distributions of near-field light emission intensity and thermal transient measurements for evaluation of thermal resistance of LEDs and its elements. It was shown that poor current spreading at high current density causes increase in thermal resistance.
The foundation of measurement systems for environmental and structural health monitoring based on molecular condensation nuclei (MCN) detector is the measurement of the intensity of light scattered by aerosol particles. Aerosol particles are formed in the condensation chamber around single molecules of detected impurities (harmful and dangerous substances in the case of environmental monitoring and biomarkers in the case of structural health monitoring). The size of an aerosol particle is about 106 times larger than the size of the original impurity molecule. The ability of the aerosol particle to scatter incident light also increases ~1014÷1016 times compared with the original molecule. By measuring the light scattering intensity the concentration of chemical impurities in the air is determined. The paper investigates many aspects of the detection process - the optical scattering by aerosol particles inside the photometer of MCN detector; signal conditioning, processing of light scattering measurements results, determination of the criteria for making a decision about the presence of detected impurities in the environment; multi-component sensing of detected impurities and graphical user interface design. Experimental results of the detection of toxic substances in micro-concentrations in the environment are presented.
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