低维相变薄膜显示器件的光学性质研究

发布时间：2018-07-29 07:54

【摘要】：基于相变材料的显示技术具有颜色对比度高、高分辨率、高速度、低功耗等突出特点。本文研究了基于相变材料的显示器件的光学性质和基于静电纺丝工艺的LED远程荧光技术所制备的背光源。将相变材料(GST)应用于显示器件,分析GST层的厚度和状态变化、ITO上下层的厚度变化对显示器件光学特性的影响。基于相变材料的显示器件本身不会发光,它需要背光光源来照明。理想的光源是全光谱光源。基于静电纺丝工艺的LED远程荧光技术所制备的光源,可以产生均匀的面光源,当采用PET塑料片时,其柔性薄片容易与显示面板集成。1.研究了相变薄膜显示器件的光学计算理论及方法和两种类型器件的反射或透射光谱与器件结构的关系。基于相变材料(GST)的显示器件的主要影响因素包括GST层的厚度及状态变化、ITO上下层的厚度,研究得出以下结论:对于反射型器件,不同下层ITO厚度下器件的反射光谱图形变化很大。当GST的状态变化时,器件显示的颜色将会出现变化。无论GST在晶态还是非晶态下,上层ITO的厚度均不影响最大反射率对应的波长。GST的厚度是11nm时,所消耗的电能最少并且器件有最好的颜色对比度。对于透射型器件,在GST薄膜层积的厚度增加后,器件的透明度降低。因此,在进行器件结构设计时要兼顾到器件的颜色对比度和透明度,可选择7nm-15nm的区域作为折中区域。2.研究了荧光片的静电纺丝制备工艺及其光学性能。得出以下结论:PVA溶液的浓度为9%,实验所加电压为25kV,喷丝头到载玻片的距离为9cm,是静电纺丝工艺的三个最优参数,纺丝效果最明显。基于静电纺丝工艺制备了黄色荧光片与红色荧光片,并测试分析了光学性能。使用分光光度计测黄色荧光片的透射率可知,荧光片的透光率很好。对使用荧光光谱测量系统测量的黄色荧光片的PL谱分析可得,光谱的峰值是不随纺丝时间的不同而有所改变的。因此,可以制备静电纺.丝时间不同的荧光片达到想要的理想效果和光学性能。利用快速光谱辐射计测量灯的光学性能参数:光通量、相关色温、光效。静电纺丝时间越长,光通量越低,光效也相应的降低。使用不同荧光粉含量的荧光片可以在保持高光效的同时,实现色温的宽幅度调节。因此,可以使用红色荧光片调整灯具发光光谱成分,改善照明质量。可通过改变荧光片的种类自由设置发光光谱成分。基于静电纺丝工艺的LED远程荧光技术所制备的光源,具有以下特性:光谱成分容易调整,结构灵活,薄层、柔性,因此适合作为背光源。
[Abstract]:The display technology based on phase change material has the advantages of high color contrast, high resolution, high speed and low power consumption. In this paper, the optical properties of the display devices based on phase change materials and the backlight prepared by the LED remote fluorescence technology based on the electrostatic spinning process are studied. The phase change material (GST) is applied to display devices, and the influence of the thickness of GST layer and its upper and lower layers on the optical properties of display devices is analyzed. The display device based on phase change material itself does not emit light, it needs backlight to illuminate. The ideal light source is a full spectrum light source. The light source prepared by LED remote fluorescence technology based on electrostatic spinning technology can produce uniform surface light source. When PET plastic sheet is used, the flexible sheet can be easily integrated with display panel. The optical calculation theory and method of phase change thin film display devices and the relationship between the reflectance or transmission spectra of two kinds of devices and the structure of the devices are studied. The main influencing factors of the display devices based on phase change material (GST) include the thickness of the GST layer and the thickness of the upper and lower layers of the GST layer. The reflectance spectra of the devices vary greatly with the thickness of the lower ITO. When the state of the GST changes, the color of the display changes. The thickness of the upper layer ITO does not affect the thickness of the wavelength corresponding to the maximum reflectivity when the thickness of the ITO is 11nm, the power consumption is the least and the device has the best color contrast, regardless of whether the GST is in the crystalline state or the amorphous state. For the transmissive devices, the transparency of the GST films decreases with the increase of the thickness of the layers. Therefore, the color contrast and transparency of the device should be taken into account in the design of the device structure, and the region of 7nm-15nm can be chosen as the compromise region. The preparation process and optical properties of fluorescent sheet by electrostatic spinning were studied. The following conclusions are drawn: the concentration of PVA solution is 9, the applied voltage is 25 kV, and the distance from the spinneret to the glass slide is 9 cm, which is the three optimal parameters of the electrostatic spinning process, and the spinning effect is the most obvious. Yellow and red fluorescent sheets were prepared based on electrostatic spinning process and their optical properties were tested and analyzed. The transmittance of yellow fluorescent film was measured by spectrophotometer. The PL spectra of the yellow fluorescent chips measured by the fluorescence spectrum measurement system show that the peak value of the spectrum does not change with the spinning time. Therefore, electrospinning can be prepared. The desired effect and optical properties are achieved with different filament time. The optical performance parameters of the lamp were measured by using a fast spectral radiometer: luminous flux, correlation color temperature, and light efficiency. The longer the electrostatic spinning time, the lower the luminous flux and the lower the light efficiency. The wide range of color temperature can be adjusted at the same time of keeping high luminous efficiency with different phosphor content. Therefore, we can use the red fluorescent chip to adjust the luminous spectral composition and improve the lighting quality. The luminescence spectrum can be freely set by changing the kind of fluorescence chip. The light source prepared by LED remote fluorescence technology based on electrostatic spinning process has the following characteristics: the spectral composition is easy to adjust, the structure is flexible, thin layer, flexible, so it is suitable as backlight source.
【学位授予单位】：天津工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN873

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