Laser excitation of red, green, blue and trichromatic white rare-earth phosphors for solid-state lighting applications

Sun

Light-Emitting Devices, Materials, and Applications

et al. 2019

We reported on the design, demonstration, and analysis of white lighting systems based on GaN laser diodes. Compared to light-emitting-diodes (LEDs), lasers have been proposed for the development of high-power light sources for many potential advantages, including circumventing efficiency droop, reduced light emitting surface, directional beam characteristics. Laser-based white light sources are also attractive for visible light communication (VLC) applications that enabling lighting and communication dual functionalities. In this work, we detailed the color-rendering index (CRI), correlated color temperature (CCT), and luminous flux analysis of laser white light sources by using the GaN laser diode exciting color converters at various driving conditions. By using a blue-emitting laser exciting a yellow YAG phosphor crystal, a luminous flux greater than 600 lm has been achieved with a moderate CRI of 67.2. By constructing a white lighting system using phosphor crystal array based on a reflection configuration, an improved CRI of 74.4 and a luminous flux of ~400 lm with a CCT of 6425 K was obtained at 3A. Using a novel ceramic phosphor plate as color converter, the CRI for the white light source has been further improved to ~ 84.1 with a CCT of ~ 4981 K, which suggests that the laserbased white light source is capable of high-quality illumination applications. The CCT of the white laser sources can be engineered from 5000 K to 6500 K and a potential approach to use laser array for high power white lighting is discussed.

Section: Blue Laser With Phosphorsmentioning

confidence: 99%

Study on laser-based white light sources

Sun

Light-Emitting Devices, Materials, and Applications

et al. 2019

“…Thus the choice of pump source is critical in attaining desired spectral attributes in the generated light. We have published our findings on LD‐based excitation of phosphors for SSL applications in another publication . This paper mainly concentrates on the, practically, more important case of phosphor excitation with LEDs.…”

Section: Pump Sources For Solid‐state Lightingmentioning

confidence: 99%

Preparation of balanced trichromatic white phosphors for solid‐state white lighting

et al. 2016

Self Cite

High quality white light-emitting diodes (LEDs) employ multi-component phosphor mixtures to generate light of a high color rendering index (CRI). The number of distinct components in a typical phosphor mix usually ranges from two to four. Here we describe a systematic experimental technique for starting with phosphors of known chromatic properties and arriving at their respective proportions for creating a blended phosphor to produce light of the desired chromaticity. This method is applicable to both LED pumped and laser diode (LD) pumped white light sources. In this approach, the radiometric power in the down-converted luminescence of each phosphor is determined and that information is used to estimate the CIE chromaticity coordinate of light generated from the mixed phosphor. A suitable method for mixing multi-component phosphors is also described. This paper also examines the effect of light scattering particles in phosphors and their use for altering the spectral characteristics of LD- and LED-generated light. This is the only approach available for making high efficiency phosphor-converted single-color LEDs that emit light of wide spectral width.

“…As a mature and economical solution, the laser‐activated phosphor has been widely used in the market as the preferred solution of laser display. Ce‐YAG and other kinds of phosphor are used to obtain light in visible bands activated by blue‐wavelength laser . In laser display, blue light is usually used to excite green, yellow, or red phosphors, or blue laser is used to excite yellow and green phosphors, and then filtered from yellow phosphor light to get red.…”

Section: Introductionmentioning

confidence: 99%

A laser current control algorithm to avoid color distortion in laser projection displays

Guo

Wang

et al. 2019

J Soc Info Display

Laser display technology has gradually become an important solution for large screen display. As a mature lighting technology in recent decades, phosphor has been widely used in the field of lighting and display. As a solid‐state light source, it has the advantages of low power consumption, environmental protection, rich color, and dynamic modulation. The luminescent efficiency of phosphors varies with temperature, which results in the nonlinearity of phosphor emission when the light source is dynamically modulated and the color temperature drift of the display image. In this paper, a control model of color temperature of laser TV display changing with laser current and temperature is established. The color temperature of laser TV is corrected by using current compensation control algorithm. The problem of color temperature drift caused by the change of phosphor conversion efficiency with t7emperature is solved. The color temperature deviation is 1118 K in the luminance range of the light source before compensation. By compensating and controlling the laser current, the ratio of blue light and phosphor is constant when the luminance changes, thus ensuring the color temperature constant when the luminance of the laser light source changes. The color temperature deviation is 50 K in the luminance range. By analyzing the different luminance of the display image, the stability of the color temperature is improved.