<b>Purpose</b> <p>Neonatal jaundice is a common condition that can lead to serious complications if left untreated. Although phototherapy is the standard treatment, existing devices are often costly, energy-intensive and fail to deliver the required intensity or provide uniform irradiance, particularly in low-resource settings. This study aims to design and optimize a low-cost, energy-efficient phototherapy bed that meets clinical requirements for irradiance intensity and spatial uniformity.</p> <b>Methods</b> <p>A multi-objective photometric optimization approach was applied to design the phototherapy bed, focusing on balancing irradiance intensity, glare control, and dark spot avoidance. Simulations were performed using a Lambertian emission model to determine the ideal LED configuration. Different LED grid layouts with varying LED spacing were simulated. The optical properties of all materials, including the LEDs, diffuser, bed flat, and mattress, were tested. The device design and assembly are described.</p> <b>Results</b> <p>The optimal LED configuration, a hexagonal grid with approximately 9&#xa0;cm spacing, yielded the best performance. The measurement verification for the Lambertian emission model showed strong agreement with the simulation results. Prototype testing achieved a mean irradiance of 44.78&#xa0;μW/cm²/nm with a relative standard deviation of 0.36. The diffuser and mattress positively influenced irradiance by improving uniformity, avoiding dark spots, and reducing glare.</p> <b>Conclusions</b> <p>This system, with a material cost of approximately $80, offers an affordable and clinically effective solution for neonatal jaundice therapy in low-resource settings. It supports home treatment and promotes mother-infant bonding. The proposed optimization methodology can serve as a design reference for future light-based therapeutic systems.</p> Graphical Abstract <p></p>