Figure 4 shows a simulation model: a pixel of the image sensor is set as a virtual light source that emits rays reversely into the aperture layers and a virtual detector is placed on the object plane, counting the rays that reach. The variable parameters are the gaps between the surfaces and the aperture sizes on each aperture layer. We searched for a solution satisfying the condition that no obliquely emitting rays reach the virtual detector. One solution is the following: the aperture sizes are 48, 40, , respectively, in the order of the first to the third layer, and the gaps are 1.0, 0.4, 0.45 mm, respectively, in the order of L1 to L3 in Fig. 4. Also, the illuminated spot on the object plane shows a field of view area of one pixel. Suppose two of the spots are placed with a gap of , a pitch of 300 dpi. When the spot size is small enough to distinguish the two spots, it means that the optics has a resolution of 300 dpi at the object distance.