Fig. 1. Schematic diagrams of curved optical element surface illumination. (a) Large divergence angle illumination; (b) small divergence angle illumination

Fig. 2. Schematic diagrams of illumination effect at different angle of incidence. (a) Ideal angular incidence; (b) large angle incidence; (c) small angle incidence

Fig. 3. Annular light source illumination. (a) Schematic diagram of multi-angle illumination; (b) schematic diagram of azimuthal symmetrical illumination compensation

Fig. 4. Schematic diagram of key parameter calculation for extended source plano-convex lens

Fig. 5. Schematic diagram of plano-convex lens design

Fig. 6. Plano-convex lens model. (a) Lens profile busbar; (b) lens 3D model

Fig. 7. Illumination at working distance of 150 mm. (a) Normal illumination; (b) oblique illumination; (c) symmetric illumination; (d) illuminance distribution of normal illumination; (e) illuminance distribution of oblique illumination; (f) illuminance distribution of symmetric illumination

Fig. 8. Illuminance distribution and divergence angle. (a) Lateral illuminance distribution curves for normal incidence at different distances; (b) angular distribution of light emitted from a single light source

Fig. 9. Illumination models with incident angles. (a) 60° incident illumination; (b) 45° incident illumination; (c) 30° incident illumination; (d) illuminance distribution of 60° illumination; (e) illuminance distribution of 45° illumination; (f) illuminance distribution of 30° illumination

Fig. 10. Illuminance distribution of ring light at different incident angles

Fig. 11. Curved optical element simulation models. (a) Concave simulation model; (b) convex simulation model

Fig. 12. Simulating the camera’s reception of reflected light. (a) Design light source; (b) 45° illumination; (c) 50° illumination; (d) classical ring light model; (e) classical ring light 45° illumination; (f) classical ring light 50° illumination

Fig. 13. Analysis of surface machining influence factors. (a) Impact of machining precision; (b) impact of cyclic errors

Fig. 14. Illuminance distribution with a 0.1 mm light source translation. (a) Illuminance distribution along the X-axis; (b) illuminance distribution along the Y-axis