High-Uniformity Planar Mini-Chip-Scale Packaged LEDs with Quantum Dot Converter for White Light Source

Chen, Lung-Chien; Tien, Ching-Ho; Chen, De Fu; Ye, Zhi Ting; Kuo, Hao‐Chung

doi:10.1186/s11671-019-2993-z

Cited by 13 publications

(12 citation statements)

References 36 publications

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“…Another modification may be to use a quantum dot film on the diffuser plate below which only blue micro-LEDs are arranged [13]. Second, the difference in refractive index between the beads and the matrix of the diffuser plate can be increased, such as by using an air pore or a high-index particle such as TiO 2 , to enhance the scattering efficiency caused by the beads.…”

Section: Resultsmentioning

confidence: 99%

Optimization of the optical structure of thin direct-lit LED backlights for LCD applications by using micro-LEDs

Lee

2019

Journal of Information Display

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The optimized optical structure of the micro-LED-based direct-lit backlight was investigated through optical simulation. The backlight consisted of only one diffuser plate and an array of micro-LEDs with a reflection film positioned on the bottom of the backlight. An additional reflector was put on top of each micro-LED to prevent the formation of bright spots. Under several number density conditions of the microbeads in the diffuser plate, stable regions were found on the gap-pitch plot, where a high Mura index of ∼ 1 was secured. The bead density needed to be small (around 10 4 mm −3) to maintain above 60% transmittance, because the transmittance of the backlight was significantly reduced at higher bead densities. Under the 10 4 mm −3 bead density condition, the gap can be reduced to 1.5 mm at a 3 mm pitch. The gap can be further reduced if additional optical films, such as a diffuser sheet, a prism film, and a reflective polarizer, will be adopted in the backlight. This work demonstrated that micro-LEDs are ideal light sources for realizing a thin direct-lit backlight for LCD applications.

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Section: Resultsmentioning

confidence: 99%

Optimization of the optical structure of thin direct-lit LED backlights for LCD applications by using micro-LEDs

Lee

2019

Journal of Information Display

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“…Among the aforementioned parameters, low central light intensity and increased peak luminous angle help improve the uniformity and viewing angle [45]. This study presents the design of a highly reflective thin-film (HRTF) layer on the surface of the micro-LEDs chip, which includes a dielectric film made of TiO 2 /SiO 2 stacked dielectric materials and a metal film made of Al.…”

Section: Micro-leds Chip Sizes and Light Field Typesmentioning

confidence: 99%

Highly Reflective Thin-Film Optimization for Full-Angle Micro-LEDs

Ho²,

Chen

2021

Nanoscale Res Lett

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Displays composed of micro-light-emitting diodes (micro-LEDs) are regarded as promising next-generation self-luminous screens and have advantages such as high contrast, high brightness, and high color purity. The luminescence of such a display is similar to that of a Lambertian light source. However, owing to reduction in the light source area, traditional secondary optical lenses are not suitable for adjusting the light field types of micro-LEDs and cause problems that limit the application areas. This study presents the primary optical designs of dielectric and metal films to form highly reflective thin-film coatings with low absorption on the light-emitting surfaces of micro-LEDs to optimize light distribution and achieve full-angle utilization. Based on experimental results with the prototype, that have kept low voltage variation rates, low optical losses characteristics, and obtain the full width at half maximum (FWHM) of the light distribution is enhanced to 165° and while the center intensity is reduced to 63% of the original value. Hence, a full-angle micro-LEDs with a highly reflective thin-film coating are realized in this work. Full-angle micro-LEDs offer advantages when applied to commercial advertising displays or plane light source modules that require wide viewing angles.

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“…QLEDs (quantum dots light-emitting diodes) utilize QDs display technology. QDs are characterized by wide absorption and narrow emission [ 21 , 22 ]. Backlight blue LEDs produce excellent red, green, and blue light through QDs films, which provide excellent color saturation performance.…”

Section: Introductionmentioning

confidence: 99%

Use of Recycling-Reflection Color-Purity Enhancement Film to Improve Color Purity of Full-Color Micro-LEDs

2022

Nanoscale Res Lett

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A common full-color method involves combining micro-light-emitting diodes (LEDs) chips with color conversion materials such as quantum dots (QDs) to achieve full color. However, during color conversion between micro-LEDs and QDs, QDs cannot completely absorb incident wavelengths cause the emission wavelengths that including incident wavelengths and converted wavelength through QDs, which compromises color purity. The present paper proposes the use of a recycling-reflection color-purity-enhancement film (RCPEF) to reflect the incident wavelength multiple times and, consequently, prevent wavelength mixing after QDs conversion. This RCPEF only allows the light of a specific wavelength to pass through it, exciting blue light is reflected back to the red and green QDs layer. The prototype experiment indicated that with an excitation light source wavelength of 445.5 nm, the use of green QDs and RCPEFs increased color purity from 77.2% to 97.49% and light conversion efficiency by 1.97 times and the use of red QDs and RCPEFs increased color purity to 94.68% and light conversion efficiency by 1.46 times. Thus, high efficiency and color purity were achieved for micro-LEDs displays. Graphical Abstract

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High-Uniformity Planar Mini-Chip-Scale Packaged LEDs with Quantum Dot Converter for White Light Source

Cited by 13 publications

References 36 publications

Optimization of the optical structure of thin direct-lit LED backlights for LCD applications by using micro-LEDs

Optimization of the optical structure of thin direct-lit LED backlights for LCD applications by using micro-LEDs

Highly Reflective Thin-Film Optimization for Full-Angle Micro-LEDs

Use of Recycling-Reflection Color-Purity Enhancement Film to Improve Color Purity of Full-Color Micro-LEDs

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