Reflector Cup Research Articles

Design and Application of Liquid Silicone Rubber Light Guide in Compact Automotive Headlamps

Traditional car headlights use halogen or high-intensity discharge (HID) lamps paired with a reflector cup, fisheye lens, and shading plate to comply with ECE112B (Headlamps with an Asymmetrical Passing Beam) regulations. This design has issues such as large and bulky volumes, and it sacrifices optical efficiency due to the shading plate. This paper proposes a solution using an LED light source coupled with a Liquid Silicone Rubber-Light Guide (LSR-LG) for compact automotive low-beam headlights. By employing the principle of total internal reflection, the light beam is confined within the LSR-LG to reduce the volume of the car lamp. Simultaneously, optimized the structure and adjusted the light distribution. In the prototype measurements, the LED combined with the LSR-LG in the compact automotive headlamps module exhibited light intensities of 11,942 cd, 12,898 cd, and 298.2 cd at measurement points 75 R, 50 R, and BR, respectively, by ECE R112B standards. Simultaneously, the design effectively reduced the car lamp module’s volume to 90.63 mm × 164.53 mm × 73.37 mm. This design offers advantages such as energy efficiency, lightweight construction, and compact size. It also complies with ECE R112B regulations, showing promising potential as an excellent choice for the next generation of automotive low-beam headlights.

Optimization research based on LED reflective cup system

Optimization research based on LED reflective cup system

Angular Color Uniformity Enhancement for Color-Mixed LEDs by Introducing a Diffusing Coating Layer

In this study, a simple and low-cost method is proposed to enhance angular color uniformity (ACU) of color-mixed light-emitting diodes (cm-LEDs) by introducing a diffuse coating layer. Optical models of the proposed cm-LEDs packaging modules were constructed by Monte Carlo ray-tracing simulation. The simulation results demonstrate the ACU enhancement of the cm-LEDs packaging modules with the application of the diffuse coating layer on the reflection cup. Owing to the strong light scattering and diffuse reflection effects of the diffuse coating layer, the different color light emitted from the different chip are sufficiently mixed. The diffuse coating layer was fabricated by spraying method. Its optical performance was demonstrated by experiments. The correlated color temperature (CCT) deviations of the cm-LEDs applying the diffuse coating layer have been reduced from 1174 K to 138 K at viewing angles ranging from -80° to +80°. A lowest luminous flux loss of 3.54% is obtained. The diffuse coating layer could also maintain the excellent ACU performance when the average CCTs changes from about 2000 K to 5200 K. Extremely small CCT deviations were obtained, which are less than 300 K at average CCTs ranging from 2000 K to 5200 K. The results demonstrate that the diffuse coating layer on reflection cup is a feasible and effective method to enhance the ACU of the cm-LEDs.

Design of rectangular composite paraboloid three-dimensional two-way lighting and energy-saving reflective cup

提出了充分利用灯具空间，具有单体双向多功能的光学设计新理念。结合LED与CPC，根据光学扩展量守恒，借助光路可逆原理与边缘光线原理，构造矩形复合抛物面。根据我国最新的《读写作业台灯性能要求》GB/T 9473-2017，以出光口半宽、台灯辐照高度、截短后杯体长度比为3个因素，设计正交实验，确定台灯矩形复合抛物面最适合参数为：出光口半宽50 mm、最大进光半角47.73°、截取杯体长度36 mm。在照明方面，该矩形复合抛物面能够满足关于A、AA级的照度和照度均匀度要求；在弱光聚集方面，其太阳能芯片位置的照度是不经聚光情况的1.25倍；在聚光模式下，太阳能芯片的光伏转化效率是非聚光模式下的1.66倍。这是对当前市面上非聚光模式收集太阳能方式的补充。

Effects of Phosphor Concentration and Leadframe Reflectivity for Phosphor-Converted LEDs

We propose the effects of phosphor concentration and leadframe reflectivity on phosphor-converted LEDs (pc-LEDs) manufactured using the dispensing method in this study. Simulation results showed that the luminous flux increased with the phosphor concentration and reflectivity of the reflective cup, even as the total output power decreased as the phosphor concentration increasing. It was also found that the leadframe reflectivity would dominate the optical and chromatic characteristics of pc-LEDs as well as the phosphor concentration. Specifically, for the pc-LEDs with a low phosphor concentration, the leadframe reflectivity and phosphor concentration were crucial factors determining the total output power and chromaticity deviation. However, for the pc-LEDs with a high phosphor concentration, only the phosphor concentration determined the chromaticity deviation.

Ceramic-on-ceramic total hip arthroplasty in patients younger than 55 years.

To review the outcomes of 65 patients younger than 55 years who underwent uncemented total hip arthroplasty (THA) using third-generation ceramic-on-ceramic prostheses. Medical records of 30 men and 35 women (80 hips) aged 18 to 55 (mean, 39) years who underwent uncemented THA using third-generation ceramic-onceramic prostheses by a single surgeon were reviewed. 61 THAs used the Reflection cup with the Synergy stem (n=49), Spectron stem (n=7), or Anthology stem (n=5), and 19 THAs used the Trident cup with the Secur-Fit stem. Outcomes were assessed based on the UCLA Activity Score and Harris Hip Score, as well as radiolucency around the implants, malposition, and subsidence on radiographs. Patients were asked about their satisfaction with current activity level (yes/no), activity limitation (no limitation, musculoskeletal limitation, psychological impediments and lack of motivation, and pain or disability of the operative hip), and change in occupational activity level (same or similar, more active, and less active or disability). The mean follow-up period was 54 (range, 24-110) months. Six patients were excluded from the analysis owing to prosthetic failure secondary to ceramic liner fracture after falling (n=2), acetabular component loosening (n=1), intolerable squeak (n=1), periprosthetic fracture (n=1), and instability (n=1). The mean UCLA Activity Score improved from 4.0 (range, 1-10) to 7.7 (range, 2-10) [p<0.001], and the mean Harris Hip Score improved from 52.8 (range, 25-69) to 91.0 (range, 38-100) [p<0.001]. No hip had evidence of subsidence, loosening, or osteolysis. 52 (80%) patients were satisfied with their activity level; 28 (43%) patients reported no activity limitation; and 57 (88%) patients kept the same or similar occupation. Ceramic-on-ceramic THA achieved acceptable clinical and radiographic outcomes.

Thermal and Optical Performance of a Light-Emitting-Diode Metal Package With an Integrated Reflector and Heat Spreader Structure

We develop a light-emitting diode (LED) metal package consisting of a reflector integrated with a heat spreader as one body. The structure functions obtained from the thermal transient measurement reveals that the integrated structure of the metal package leads to improved thermal performance. We make significant efforts to clarify the interaction between the extracted light from the LED chip and the inside surface of the metal package. The radiant flux from the LED chip is calculated from the definition of thermal resistance and is implemented as an input parameter to predict the optical power and ray tracing. The simulated optical output power in the far-field mode is 145.3 mW, which is in good agreement with the value measured by an integrating sphere. It is shown that a large portion of the emitted light (37.12 mW) is lost by the interaction with the package surface before it reaches the far-field receiver. It is demonstrated that the angle of the first reflector cup is one of the critical design parameters in the metal package structure that we investigate. When the first reflector angle is optimized from 80° to 55° (with the second reflector angle of 50°), the optical power increases from its original value of 145.3-170.15 mW with an improved optical extraction efficiency from 75.63% to 88.57%. The ray tracing and illuminance raster charts also confirm that the improved optical performance of the metal package mainly stems from the optimization of the reflector angles.

Design of High Power RGB White Light Emitting Diodes

In this paper, thermal performance of RGB white LED packages was optimized by thermal simulation using the Finite Volume method. A Monte Carlo photon simulation method was utilized for the analysis of optical performance of LED in quantitative terms. It was found that the distribution of RGB chips has great effect both on the thermal and optical performance of the RGB white LEDs. The tilted angle, material of the reflection cup, and the shape of encapsulant were found to be the key factors which determine the extraction efficiency of LED package. It is demonstrated that the combination of optical and thermal simulation provides a comprehensive optimization approach for a design of high efficient RGB white LED package.

Design of the Diffuse Reflector Cup with Microstructure and the Research on the Optical Performance

The reflective properties and illumination uniformity of the polymer can be improved effectively with microstructure on the surface and scattering particles with high refractive index inside. The paper is based on the early research of the author. The reflector cup is processed by injection molding using the polymer of high reflective properties, which can achieve high efficiency of the light energy utilization and the uniform emergent ray.

Conformal Phosphor Distribution for White Lighting Emitting Diode Packaging by Conventional Dispensing Coating Method With Structure Control

Conformal phosphor distribution is a well known way to improve optical performance for white light emitting diode (LED) packaging. However, it is difficult to be realized by mature and cheap dispensing coating methods. In this paper, with consideration given to the effect of boundary constraint on liquid wetting morphology, a method to achieve phosphor conformal distribution is presented by conventional dispensing coating with controlling the slanting angle of reflector cups. The numerical simulations and experiments on phosphor dispensed into reflector cups with different slanting angles are conducted. The results show that uniform phosphor distribution can be obtained when the slanting angle is the same as the contact angle between the phosphor slurry and the reflector cup side wall. The rule can be used to guide the design of the reflector cup and a simple change of reflector cup can realize phosphor conformal coating for white LEDs by the low cost traditional dispensing coating process.

High Efficient Color-Separation Backlight

To replace the color filter in the conventional display, we describe a color-separation backlight consisting of three modules: the light collimation module, the light guide and the micro-lens array. With angularly positioned color LEDs, the displaying method requires only two two-color filter layers to display color images. In the light collimation module, the angular rays of two colors from each LED are collimated by a reflective cup and a collimation lens. After entering the light guide, which is composed of V-groove structures at the bottom above a reflective layer, the angular collimated color beams are redirected to the normal of the top surface of light guide. Finally, the output rays are converged by a micro-lens array and mapped into corresponding sub-pixel positions for efficiently displaying color image. The three main advantages of such technology are the reduction of the dye color filter layers from conventional 3 to 2, the gain factor of transmission efficiency two times more than that of conventional color filters, and the larger color gamut.

Separation Distance Dependence of Luminous Efficiency in Phosphor-Converted White-Light-Emitting Diodes Fabricated Using Open Remote Method

Phosphor-converted white-light-emitting diodes (WLEDs) were fabricated using the open remote method. The separation distance between the blue LED chip and phosphor layer was varied to examine the effects of blue lights penetrating through the annular gaps between the phosphor layer edge and reflector cup walls on the luminous efficiency of the WLED. The WLEDs with a separation distance of 0.55 mm showed the highest luminous efficiency which was close to that of the slurry sample, while the amount of phosphors used was less than 25% of the amount used in the slurry sample. These results suggest that the phosphor quantity used for fabricating the WLEDs can be reduced considerably by the open remote method without any significant loss of luminous efficiency.

Highly visible-light reflective SiOxNy nanowires for bright-white reflector applications

Large quantities of single-crystal silicon oxynitride (SiOxNy) nanowires were synthesized on silicon substrate by a vapor–solid mechanism without using any catalyst. These single crystalline nanowires are 50 to 200nm in diameter, and a few hundreds of micrometers to several millimeters in length with high N concentration. The obtained SiOxNy nanowires are attractive by their exceptional whiteness, perceived brightness, and optical stability at high temperature. The experimental results show that the nanowire mat displays strong diffusive reflection over the whole visible wavelength, with more than 80% of light reflected at the wavelength range from 400 to 780nm. It is also demonstrated that the grown nanowires can be applied as coating material over reflector cup surface for white light-emitting diode lamp. It is shown that trapped modes can be significantly reduced by increasing the diffuse reflectivity of the reflector cup thus improving the lighting efficiency.

Effects of packaging structure on optical performances of phosphor converted light emitting diodes

Effects of tilt angles of reflective cup structure and phosphor surface geometries on light extraction efficiency and angular color uniformity (ACU) of phosphor converted light emitting diodes (pcLED) are investigated by Monte Carlo ray-tracing simulations. It is found that tilt angles of reflective cup and phosphor surface geometries affect the light extraction efficiency and the ACU distinctly. When the tilt angle varied from 60° to 15°, the light extraction efficiency of LED can achieve the improvements of 13.87%, 18.25% and 14.79% respectively, when the phosphor surface geometry is concave, flat and convex, respectively. It is also found the variety law of phosphor concentrations with the change of tilt angles and phosphor surface geometries to maintain a fixed correlated color temperature (CCT).

基于复合式抛物面聚光器的LED反光杯建模研究

基于复合式抛物面聚光器的LED反光杯建模研究

Growth of highly bright-white silica nanowires as diffusive reflection coating in LED lighting

Large quantities of silica nanowires were synthesized through thermal treatment of silicon wafer in the atmosphere of N(2)/H(2)(5%) under 1200 °C with Cu as catalyst. These nanowires grew to form a natural bright-white mat, which showed highly diffusive reflectivity over the UV-visible range, with more than 60% at the whole range and up to 88% at 350 nm. The utilization of silica nanowires in diffusive coating on the reflector cup of LED is demonstrated, which shows greatly improved light distribution comparing with the specular reflector cup. It is expected that these nanowires can be promising coating material for optoelectronic applications.

Investigation of the influence of structural parameters of a Fresnel-type lens on the narrowing of light-emitting diode light beams

In this study, an influence of the structural parameters of a three-dimensional (3D)-Fresnel-based lens which was designed as a primary optic on the narrowing of light-emitting diode (LED) light beams has been investigated and proposed to gather the emitted light into a narrow-angle light beam. Most conventional LEDs are not able to create a narrow-angle light beam without using a reflector cup or secondary optics, because the LED lighting angle is usually wide (±30 deg from the centerline of the light source). Nevertheless, the energy of the LED light within the range ±16 deg from the centerline of the light source can be greatly enhanced by the focusing effect of a 3D-Fresnel-based lens design as shown in this study. The illumination and the luminous flux of the LED light beam in comparison with the conventional LED have been respectively enhanced up to 61% and 20% respectively. The main contribution of this study is to adjust the height/width ratio of the ladder-shaped structure of a 3D-Fresnel-based lens in order to focus the LED light into a stronger beam, and to meet some specific working circumstances.

Optical Wireless Digital-Sound Transmission System With 1-Bit $\Delta \Sigma $-Modulated Visible Light and Spherical Si Solar Cells

Spherical Si solar cells (diameter of 1 mm) with a reflector cup (diameter of 2.2 mm) were used with 1-bit ΔΣ-modulated illumination from white LEDs to provide optical wireless digital-sound transmission. The solar cells have a high directivity with regard to incident light, thus largely eliminating the environmental noise from fluorescent lighting. An optical wireless transmission system consists of a transmitter and a receiver. The transmitter contains a battery-operated lamp with 50 white LEDs and a 1-bit ΔΣ modulator that controls the current to the lamp. The receiver consists of just a spherical-solar-cell module and an earphone. In the experiment, the transmitter converted a 1-kHz analog signal into digital pulses at a sampling frequency of 1 MHz and sent the digital data over a distance of 50 cm at an illumination of 70 lx. The measured output spectrum of the receiver showed that it recreated a sinusoidal waveform with little distortion. Even under fluorescent lighting with an illumination of 200 lx, the measured spectrum showed that a sinusoidal waveform with a signal-to-peak-noise ratio of 25 dB was obtained.

High extinction ratio polarized light guide with layered cross stacking nanostructure

Cross stacking of aluminum and PMMA strip nanostructure has been proposed as a reflective polarizer on the top surface of a solid light guide plate for polarization recycling in order to increase the efficiency of a side edge type backlight module for liquid crystal display. In order to exploit the range of light incident angle on the layered nanostructure with high extinction ratio, a dedicated backlight illumination optics for LED light source has been designed for controlling the light propagation direction within the light guide while achieving satisfactory uniformity in the meantime. The illumination optics features a reflective cup in front of the LED source and one-dimensional V-groove on the bottom surface of the light guide as the light extraction pattern. Ray tracing simulation has shown that a 4 in. diagonal light guide with proposed architecture has achieved uniformity of 75% while having the extracted light well constrained within the range of incident angle on the layered nanostructure where extinction ratio above 1000 can be obtained.

Enhanced Thermal Dissipation and Light Output of GaN/Sapphire Light-Emitting Diode by Direct Cu Electroplating

Using the self-alignment lithography and copper (Cu) electroplating techniques, a lateral-electrodes GaN light-emitting diode (LED) with a micro reflective cup and heat spreader has been demonstrated. In this work, the photoresist is used to be the electroplating forms and to produce micro reflective cup and 9 mm2 heat spreader. Under 1 A current driving, the LEDs with direct thermal spreader has an output power of 700 mW and a power conversion efficiency is upto 2 times as compared with that of the lateral-electrodes LEDs only on sapphire without current spreader. The performance of LEDs with a micro reflective cup and heat spreader is almost the same (even better) as the vertical-electrodes LEDs on Cu substrate.