激光直写凹球面网栅的电控实现

凹球面网栅激光直写系统采用同心结构,应用调节角速度的控制算法以及周期纬线纬纬相交形成网栅的图形结构,确保激光直写光斑在不同的纬度以不同角速度扫描,始终保持线速度和曝光量恒定,实现了在凹球面上以恒定曝光量激光直写网栅。分析了网格周期、角速度和纬线弧长等关键参数,设计了控制程序。在通光孔径60 mm的普通玻璃凹球面上进行了多组激光直写试验,设定周期450~800 μm,线速度1~20 mm/s,经显影、定影后由微米级读数显微镜测得网格实际周期与设定周期误差在±3%以内,原子力显微镜测得线宽小于5 μm。结果表明:采用同心结构及稳光、调速控制保证凹球面网栅激光直写系统的曝光量不变,线条侧壁陡直、平行,具有较好的均匀性,满足了设计要求。

Realization of electric control of laser direct writing mesh on concave spherical substrate

By using a concentrical configuration,a control arithmetic of adjusting the angular velocity and a mesh pattern of periodical latitude lines intersecting periodical latitude lines perpendicularly to ensure the writing spot scanning at different angular velocities in different latitudes and to keep the linear velocity and exposure dose invariable all the time in the laser direct writing system the invariable exposure dose laser direct writing mesh on the spherical substrate was realized.The key parameters such as the periods of gridding,the angular velocity and the arc length of the latitude lines were analyzed and the control program was designed.Several group experiments of laser direct writing mesh on the concave spherical substrate made of common glass with φ60 mm were done at periods of 450～800 μm and linear velocity of 1～20 mm/s.After development and fixation,the error of gridding periods measured by micron level reading-microscope is within ±3%.Line width measured by AFM is lessthan 5 μm.The experiments results indicate that the concentrical configuration and control of steady light and angular velocity adjusting have ensured the exposure dose invariable,which make laser direct writing lines on the spherical substrate have good uniformity,steep and straight side walls parallel to each other for satisfying the design requirements.