Fig. 1. Schematic of using freeform surface array to achieve uniform illumination

Fig. 2. (a) Illuminance distribution of the collimated laser; (b) illuminance distribution of the collimated laser through the freeform surface array

Fig. 3. Structure of laser illumination system

Fig. 4. Schematic diagram of unit vector of outgoing ray calculation at any point of freeform surface

Fig. 5. Topological relation of coordinate system between the freeform surface and the target surface

Fig. 6. Schematic of freeform surface constructed by geometric method

Fig. 7. Illuminance distribution at X=0 and Y=0 on the focal plane of convergent lens

Fig. 8. Illuminance maps of target surface corresponding to different lengths of round bar. (a) 60 mm; (b) 70 mm; (c) 80 mm

Fig. 9. (a) Illuminance distribution of the emergent light from combiner system; (b) latitude and (c) longitude distribution of the energy density of the emergent light from combiner system

Fig. 10. (a) Schematic of freeform surface unit uniform light; (b) normal vector error of the freeform surface model; (c) illuminance distribution of target surface; (d) illuminance curves at X=0 and Y=0 on the target surface

Fig. 11. Results of laser illumination light path and ray tracing

Fig. 12. (a) Relationship between target surface uniformity and array number of freeform surface units with different aspect ratios; (b) illuminance distribution and (c) energy distribution of the 4.5455 mm×4.5455 mm freeform surface lens; (d) illuminance distribution and (e) energy distribution of the 6.25 mm×3.515625 mm freeform surface lens

Table 1. Parameters of convergent lens

Table 2. Parameters of collimating lens

Table 3. Size and array number of freeform surface units