Optical Design And Research Of Direct-lit LED Lamps

With the rapid development of solid-state lighting technology,the LED lamp has been widely applied into indoor and outdoor lighting and special lighting.Aiming at addressing the problem of optical lens for the mainstream lamp,such as the LED panel light and the LED advertising light boxes,a new corresponding optical lens for LED lamps is designed.And aiming at addressing the problems of uniformity of spatial spectral distribution for the LED neonatal jaundice phototherapy lamp,the array arrangement that consists of different monochromatic LEDs is designed on the same substrate,which improves the lighting quality of the LED lamps effectively.First of all,to reduce further the thickness of the direct-lit LED panel light,the illumination distribution of the target plane of the Lambertian type LED at a height of 96 mm is used as the designed illumination distribution to optimize the feedback of the large angle LED lens,and form a light field with a designed illumination distribution on a target plane with a height of 25 mm.The software LightTools is used to simulate and analyze the illumination uniformity of the target plane of LED lens unit array.Results show that the illumination uniformity value of the target plane at a height of 25 mm is approximately 0.88,which meets the national technical requirements for the application of the LED indoor lighting.Then,the large angle LED lens and the white LEDs in the commercial market are selected to match,which forms a large light field on a target plane at a height of 30 mm.And the illumination distribution on the target plane is similar to the illumination distribution of the target plane of the Lambertian type LED at a height of 132 mm.Finally,this article produces an ultra-thin direct-lit LED panel light whose actual height of the target plane is 29.5 mm and the illumination distribution uniformity value of the target plane is approximately 0.84.Secondly,the secondary lens and the LED could be matched to design the large rectangular direct-lit LED advertising light boxes in general,which easily makes energy waste and forms a terrible illumination distribution.Based on the law of conservation of energy and the mesh generation method,a first LED lens for the large rectangular LED advertising light boxes is designed,which could achieve a uniform rectangular light field.The software LightTools is used to simulate and analyze the illumination uniformity of LED first lens unit array on the target plane at a height of 100 mm,and results show that the uniformity value of the illumination distribution on the target plane is approximately 0.92.Finally,to address the problem of low uniformity of spatial spectral distribution and low energy efficiency on the receiving surface(baby crib)for the direct-lit LED jaundice phototherapy lamp which consists of four kinds of monochromatic LEDs with different peak wavelength and number.According to the order of the number of LED from less to more,the array arrangement which consists of four kinds of monochromatic LEDs is designed on the same substrate,which could achieve uniform spatial spectral distribution on the illuminance surface of the LED jaundice phototherapy lamp and further realize uniform spatial spectral distribution on the receiving surface.Placing the diffusion plate or brightness enhancement film on the illuminance surface of direct-lit LED jaundice phototherapy lamp respectively,two kinds of LED jaundice phototherapy lamp samples are produced and the corresponding experiments are tested.Results show that two kinds of LED jaundice lamp samples all achieve uniform spatial spectral distribution and illumination distribution on the receiving surface,and the LED jaundice lamp sample placing the brightness enhancement film in its illuminance surface can make the receiving surface receive more energy.