Fig. 1. PCB substrate

Fig. 2. I-V characteristic curves non-aging and after 500, 1000, 1500 h aging under working conditions

Fig. 3. Spectra curves non-aging and after 500, 1000, 1500 h aging under working conditions

Fig. 4. Radiant efficiency of non-aging and after 500, 1000, 1500 h aging under working conditions

Fig. 5. Radiant flux maintenance change over time

Fig. 6. Normal failure probability distribution curve of L₇₀ on actually testing

Fig. 7. Exponential fitting model. (a) 500‒3500 h; (b) 500‒4500 h; (c) 500‒5500 h

Fig. 8. LED#5. (a) MCMC sampling trajectory; (b) distribution diagram

Fig. 9. LED#10. (a) MCMC sampling trajectory; (b) distribution diagram

Fig. 10. Bayesian MCMC fitting diagram

Fig. 11. Power function fitting diagram

Fig. 12. Logarithmic function fitting diagram

Fig. 13. Comparison of fitting model errors