提出一种具有凹面阴极结构的电子束自会聚型后栅场发射显示器(FED)。利用Ansys软件模拟此器件的电场分布和电子束轨迹，研究凹面阴极不同曲率半径对阳极光斑尺寸的影响，并与平面阴极型后栅FED进行比较。仿真结果表明此器件可有效减小电子束的发散角和阳极光斑尺寸，阳极光斑尺寸随着凹面阴极曲率半径的减小而减小，同时可获得更高的电流密度。利用丝网印刷技术制备10 cm×10 cm的电子束自会聚型后栅FED，对其场发射性能进行测试。结果表明此器件可有效减小阳极光斑尺寸，提高显示器的分辨率；阳极电压为600 V，栅极电压在100～250 V范围内对电子发射有良好的调控作用。

An under-gate field emission display (FED) with a concave cathode is proposed. Ansys software is used to simulate the electric field distribution and the focus effect of electron beams. The curvature radius of a concave cathode which affects the self-focus is investigated. The results demonstrate that the concave cathode focuses electron beams which emit from cathode obviously. As the curvature radius of a concave cathode decreases, the focus effect is enhanced and the radius of spots on the anode decreases too. A 10 cm×10 cm FED with a good self-focus effect is successfully prepared using screen printing. The field emission image shows that the structure can decrease the size of spots and improve the resolution. The anode current is well modulated by a gate voltage of 100～250 V under an applied anode voltage of 600 V.