We present a two-step two-frequency up-conversion (TSTF-UC) fluorescent material based crossed-beam display (CBD) apparatus. 3D voxels are addressed by two IR laser beams, which are driven by fast acousto-optic light deflectors (AOLD). The compact scanning system can cover a display volume of 100mmx100mmx100mm. Initial demonstration was carried out with a piece of 0.5-mol % Er<sup>3+</sup>-doped ZBLAN glass (23mmx23mmx17mm). It was found that the 3D image brightness dropped dramatically when refresh rate was increased. Also “ghost” voxels appeared with increasing refresh rate. A simplified rate-equation analysis was performed to address the issues.