scholarly journals Fabrication of Random Microlens Array for Laser Beam Homogenization with High Efficiency

Micromachines ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 338 ◽  
Author(s):  
Li Xue ◽  
Yingfei Pang ◽  
Wenjing Liu ◽  
Liwei Liu ◽  
Hui Pang ◽  
...  
Keyword(s):  
Laser Beam ◽  
High Efficiency ◽  
Cost Effective ◽  
Microlens Array ◽  
High Energy ◽  
Light Spot ◽  
Energy Utilization ◽  
Utilization Rate ◽  
Laser Systems ◽  
High Coherence

The miniaturized and integrated microlens array (MLA) can effectively achieve the beam homogenization, compactness and miniaturization of laser systems. When the high-coherence laser beam is homogenized by means of using the MLA, interference fringes will occur in the homogenized light spot due to the periodicity of the MLA, which seriously affects the uniformity of the homogenized light spot. To solve this problem, a novel random microlens array (rMLA) structure was proposed for the purpose of achieving beam homogenization. The coherence in the homogenization process is suppressed by means of breaking the periodicity of the MLA. The homogenized light spot with a high energy utilization is then obtained accordingly. In the fabrication process, a clever method of combining chemical etching with lithography technology is performed to fabricate a honeycomb rMLA and a rectangular rMLA. The experimental results show that the energy utilization rate of the two types of the rMLAs is about 90%, and the uniformity of the homogenized light spots generated by the honeycomb rMLA and the rectangular rMLA are more than 80% and 85%, respectively. Meanwhile, fully cost-effective fabrication is possible to be realized.

scholarly journals Integrated Double-Sided Random Microlens Array Used for Laser Beam Homogenization

Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 673
Author(s):  
Wei Yuan ◽  
Cheng Xu ◽  
Li Xue ◽  
Hui Pang ◽  
Axiu Cao ◽  
...  
Keyword(s):  
Laser Beam ◽  
Microlens Array ◽  
Energy Utilization ◽  
Utilization Rate ◽  
Periodic Lattice ◽  
Lattice Distribution ◽  
Speckle Field ◽  
High Laser ◽  
Alignment Problem ◽  
In Series

Double microlens arrays (MLAs) in series can be used to divide and superpose laser beam so as to achieve a homogenized spot. However, for laser beam homogenization with high coherence, the periodic lattice distribution in the homogenized spot will be generated due to the periodicity of the traditional MLA, which greatly reduces the uniformity of the homogenized spot. To solve this problem, a monolithic and highly integrated double-sided random microlens array (D-rMLA) is proposed for the purpose of achieving laser beam homogenization. The periodicity of the MLA is disturbed by the closely arranged microlens structures with random apertures. And the random speckle field is achieved to improve the uniformity of the homogenized spot by the superposition of the divided sub-beams. In addition, the double-sided exposure technique is proposed to prepare the rMLA on both sides of the same substrate with high precision alignment to form an integrated D-rMLA structure, which avoids the strict alignment problem in the installation process of traditional discrete MLAs. Then the laser beam homogenization experiments have been carried out by using the prepared D-rMLA structure. The laser beam homogenized spots of different wavelengths have been tested, including the wavelengths of 650 nm (R), 532 nm (G), and 405 nm (B). The experimental results show that the uniformity of the RGB homogenized spots is about 91%, 89%, and 90%. And the energy utilization rate is about 89%, 87%, 86%, respectively. Hence, the prepared structure has high laser beam homogenization ability and energy utilization rate, which is suitable for wide wavelength regime.

scholarly journals Research on Green Productivity of Chinese Real Estate Companies—Based on SBM-DEA and TOBIT Models

2020 ◽  
Vol 12 (8) ◽  
pp. 3122
Author(s):  
Zhao Yang ◽  
Hong Fang
Keyword(s):  
Real Estate ◽  
Information Disclosure ◽  
Negative Impact ◽  
Malmquist Index ◽  
High Energy ◽  
Energy Utilization ◽  
Productivity Index ◽  
Utilization Rate ◽  
Green Innovation ◽  
Green Productivity

Apart from promoting social-economic development and increasing social employment, the real estate industry in China has also brought up problems such as high energy consumption and high emissions. Scholars now focus more on energy conservation, emission reduction and sustainable development of real estate companies in their current research. The data used by this paper are three-year panel data from 2015 to 2018, with observations from 15 representative real estate companies. CO2 and green credit index are introduced as the undesirable output and the green output of real estate companies respectively. First, with the DEA model and the Malmquist index model, this paper evaluates the green productivity of real estate companies statically and dynamically. The Tobit model is then employed by the author to analyze factors that may affect green productivity. Our results indicate that (1) the green productivities of 15 Chinese real estate companies have improved by various degrees. The average green productivity rises from 0.701 in 2015 to 0.849 in 2018, indicating that the energy utilization rate of enterprises has gradually increased. From the calculation and decomposition of the Malmquist total factor productivity index, we know that technological progress is vital in improving the green productivity of real estate companies. (2) As for the influencing factors, the green productivity is positively related to factors such as policy compliance indicator P, environmental responsibility commitment indicator R, indicator of green innovation capability I, and indicator of green development information disclosure M. The asset-liability ratio on the contrary has a negative impact on green productivity. It’s worth to point out that the green innovation index and green productivity is significantly correlated and the correlation coefficient can be up to 0.636, which implies that the key to improving green productivity is to increase research and development investment.

Design of Projection Light Source for Solid Volumetric True-3D Display

2013 ◽  
Vol 321-324 ◽  
pp. 466-469
Author(s):  
Guang Lei Yang ◽  
Chang Long Jing ◽  
Hui Hui Yao ◽  
Qi Bin Feng
Keyword(s):  
Light Source ◽  
High Power ◽  
High Energy ◽  
Luminous Flux ◽  
Energy Utilization ◽  
Utilization Rate ◽  
3D Display ◽  
High Brightness ◽  
Light Emitting ◽  
Measurement Results

The solid volumetric true−3D display requires light source with high brightness, high energy utilization rate and high frequency color field. So high−power red, green and blue LEDs with collimators were used as the projection light source. Firstly, the required quantity of LEDs was determined according to the required output luminance, the efficiency of the projector and the red, green and blue LEDs' parameters. Secondly, with the consideration of the LEDs' dimensions, light−emitting mode and output luminous flux, collimator was designed and simulation model was established. Simulation and practical measurement results both show that light source based on high−power LED meet the requirements of the solid volumetric true−3D display.

scholarly journals A Study of High-Efficiency Laser Headlight Design Using Gradient-Index Lens and Liquid Lens

2020 ◽  
Vol 10 (20) ◽  
pp. 7331
Author(s):  
Yi-Chin Fang ◽  
Yih-Fong Tzeng ◽  
Chan-Chuan Wen ◽  
Chao-Hsien Chen ◽  
Hsiao-Yi Lee ◽  
...  
Keyword(s):  
Laser Beam ◽  
Light Source ◽  
High Efficiency ◽  
Optical Design ◽  
Energy Conversion Efficiency ◽  
High Energy ◽  
Gradient Index ◽  
High Beam ◽  
Liquid Lens ◽  
Gradient Index Lens

In the field of vehicle lighting, due to the diode laser, its small size and high energy conversion efficiency, it can be effectively used as the headlight source of high beam. In recent years, it was adopted by European advanced car manufacturers as a new generation of automotive headlight lighting products. The current mature technology on the market is to extend the laser beam by means of reflection and to use a single high-power laser as the light source to meet the needs of surface lighting. In this research, we propose a new integrated optical design for an automotive headlight system with the rod lens, gradient-index lens (GRIN lens) and freeform lens to expand the laser beam. With regard to the diffusion of the beam by reflection and refraction, the liquid lens is used as a switch for the high beam and low beam lights to meet the needs of vehicle lighting functions and to use low-power diode lasers to synthesize the array light source. Compared with the 24-W LED headlight module available in the current market, the energy saved by this proposed optical design can increase efficiency by an average of 33%. The maximum illuminance is 56.6 lux in the high-beam mode, which is 18% higher than the standard value. Let the laser light meet the lighting requirements of regulatory standard values even beyond.

scholarly journals Technical economic model of energy utilization and energy saving for central heating system

2021 ◽  
Vol 25 (4 Part B) ◽  
pp. 3113-3121
Author(s):  
Guojing Geng ◽  
Xianzhe Li
Keyword(s):  
Energy Saving ◽  
Economic Model ◽  
Heating System ◽  
High Energy ◽  
Energy Utilization ◽  
Utilization Rate ◽  
Heating Method ◽  
Energy Saving Potential ◽  
Central Heating ◽  
Exergy Balance

Chinese heating method has gradually shifted from small fragments to centralized regional heating. This heating method has achieved obvious energy-saving benefits. The article establishes an economic model of the energy utilization rate of the central heating system and installs the system exergy balance equation at the same time. The simulation found that the energy utilization coefficient of the heating system is high and has a high energy-saving potential. The effect of energy utilization is poor, and it has great potential for energy saving.

Static Converter for High Energy Utilization, Modular, Small Nuclear Power Plants

2002 ◽  
Author(s):  
Mohamed S. El-Genk ◽  
Jean-Michel P. Tournier
Keyword(s):  
Power Plants ◽  
High Efficiency ◽  
Sea Water ◽  
Thermal Power ◽  
Ambient Air ◽  
High Energy ◽  
Water Desalination ◽  
Energy Utilization ◽  
Space Heating ◽  
Thermodynamic Efficiency

This paper presents and analyzes the performance of high efficiency, high total energy utilization, static converters, which could be used in conjunction with small nuclear reactor plants in remote locations and in undersea applications, requiring little or no maintenance. The converters consist of a top cycle of Alkali Metal Thermal-to-Electric Conversion (AMTEC) units and PbTe thermoelectric (TE) bottom cycle. In addition to converting the reactor thermal power to electricity at 1150 K or less, at a thermodynamic efficiency in the low to mid thirties, the heat rejection from the TE bottom cycle could be used for space heating, industrial processing, or sea water desalination. The results indicated that for space heating applications, where the rejected thermal power from the TE bottom cycle is removed by natural convection of ambient air, a total utilization of the reactor thermal power of > 80% is possible. When operated at 1030 K, potassium AMTEC/TE converters are not only more efficient than the sodium AMTEC/TE converters but produce more electrical power. The present analysis showed that a single converter could be sized to produce up to 100 kWe and 70 kWe, for the Na-AMTEC/TE units when operating at 1150 K and the K-AMTEC/TE units when operating at 1030 K, respectively. Such modularity is an added advantage to the high-energy utilization of the present AMTEC/TE converters.

scholarly journals Vertical U-shaped heat exchangers for construction engineering: New promises and future challenges

2021 ◽  
pp. 113-113
Author(s):  
Yin Liu ◽  
Sensen Xu ◽  
Dongyan Yuan ◽  
Zhaofeng Meng ◽  
Long Gao
Keyword(s):  
Heat Exchangers ◽  
High Efficiency ◽  
Branch Pipe ◽  
Green Energy ◽  
Energy Utilization ◽  
Utilization Rate ◽  
Pump System ◽  
Technical Problems ◽  
Heat Pump System ◽  
Construction Engineering

The ground source heat pump system is a promising technology for building heating and cooling by using underground energy, however, many technical problems, e.g. low energy utilization rate and inefficiency operation, have greatly hindered its wide applications. This paper studies the key technologies of vertical U-shaped heat exchangers in construction engineering to solve the bottleneck problem and optimizes the system. Three commonly used backfill methods are analyzed, and a double U-shaped branch pipe is recommended to improve construction efficiency. The paper sheds a bright light on green energy utilization with high-efficiency, energy-saving, and environmental protection.

Janus – A New Approach to Air Combat Pilot Training

2019 ◽  
Vol 2019 (4) ◽  
pp. 7-22
Author(s):  
Georges Bridel ◽  
Zdobyslaw Goraj ◽  
Lukasz Kiszkowiak ◽  
Jean-Georges Brévot ◽  
Jean-Pierre Devaux ◽  
...  
Keyword(s):  
Low Cost ◽  
Cost Effective ◽  
High Energy ◽  
Training System ◽  
Embedded Sensors ◽  
Pilot Training ◽  
New Approach ◽  
Combat Aircraft ◽  
Air Combat ◽  
The Cost

Abstract Advanced jet training still relies on old concepts and solutions that are no longer efficient when considering the current and forthcoming changes in air combat. The cost of those old solutions to develop and maintain combat pilot skills are important, adding even more constraints to the training limitations. The requirement of having a trainer aircraft able to perform also light combat aircraft operational mission is adding unnecessary complexity and cost without any real operational advantages to air combat mission training. Thanks to emerging technologies, the JANUS project will study the feasibility of a brand-new concept of agile manoeuvrable training aircraft and an integrated training system, able to provide a live, virtual and constructive environment. The JANUS concept is based on a lightweight, low-cost, high energy aircraft associated to a ground based Integrated Training System providing simulated and emulated signals, simulated and real opponents, combined with real-time feedback on pilot’s physiological characteristics: traditionally embedded sensors are replaced with emulated signals, simulated opponents are proposed to the pilot, enabling out of sight engagement. JANUS is also providing new cost effective and more realistic solutions for “Red air aircraft” missions, organised in so-called “Aggressor Squadrons”.

Sign in / Sign up

Export Citation Format

Share Document