自由立体显示器定向背光侧面发光光纤

Side-Glowing Optical Fiber as Directional Backlight in Autostereoscopic Display

设计并研究了一种采用激光打标机在塑料光纤(POF)表面雕刻散射点的侧面均匀发光光纤,可用作自由立体显示器的定向背光光源。通过建立激光打标凹形散射点的POF均匀发光模型,推导了POF均匀发光的散射点坐标计算公式。针对设计的凹形散射点参数,用SolidWorks软件构建侧面发光光纤模型,用TracePro软件进行光线追迹仿真。结果表明,散射点长度半圆心角(用于表征凹形散射点的深度和横向长度)的微小变化对发光亮度均匀度影响较大,而凹形散射点轴向宽度的微小变化对POF侧面发光均匀度影响很小。对各参数进行设计优化后,得到POF半径R=0.25 mm,凹形散射点宽度d=0.15 mm,散射点长度半圆心角θ=15°,POF长度L=600 mm,TracePro软件仿真得到POF侧面发光亮度均匀度为87.5%。根据设计优化后的参数采用激光打标机进行激光雕刻POF表面散射点,得到单根POF的侧面发光亮度均匀度为80.90%。将100根侧面发光POF紧密排布成面光源,得到面光源发光亮度均匀度为88.91%。实验结果表明所提出的设计方法和制作的POF面光源能满足自由立体显示器指向性背光源设计的要求。

A kind of uniformly-side-glowing optical fiber is designed and studied, which is obtained by scattering points graved on the plastic optical fiber （POF） by laser marking. This new fiber can be used as a directional backlight source for the autostereoscopic display. The model for a uniform side-glowing POF with laser marking engraved concave scattering points is established and used to derive the formula for calculating the scattering point coordinates. With the designed concave scattering point parameters, the model of side-glowing plastic optical fiber is established by the SolidWorks software, and the light ray tracing simulation is carried out based on the TracePro software. The results show that the tiny length semicircular angle change of scattering points, used for the characterization of depth and horizontal length of concave scattering points, has a large impact on the luminance uniformity. In contrast, the tiny axial width change of concave scattering points has a little impact on the sideglowing luminance uniformity. When the parameters are optimized, one can get the POF radius of R = 0.25 mm, the concave scattering point width of d = 0.15 mm, the scattering point length semicircular angle of θ=15°, the POF length of L = 600 mm and the POF side-glowing luminance uniformity of 87.5 % obtained by the TracePro simulation. According to the optimized design parameters, laser marking is used for graving scattering points on the POF surface and the obtained side-glowing luminance uniformity of single POF is 80. 90%. Furthermore, a luminescence uniformity of 88.91% can be realized if the surface light source is composed of 100 side-glowing POFs. The experimental results show that the proposed design method and the fabricated POF surface light sources can meet the requirements of the directional backlight source design for 3D autostereoscopic display.