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Demand for optical glass device used for lighting could increase rapidly because of LED lighting market growth. The optical glass devices that have been formed by hot press molding process the desired optical performance without being subjected to mechanical processing such as curve generation or grinding. EL-Max material has been used for many engineering applications because of their high wear resistance, high compressive strength, corrosion resistant and very good dimensional stability. EL-Max is very useful for a glass lens mold especially at high temperature and pressure. The performance and reliability of optical components are strongly influenced by the surface damage of EL-Max during grinding process. Therefore, the severe process condition optimization shall be necessary for the highly qualified EL-Max glass lens mold. To get the required qualified surface of EL-Max, the selection of type of the diamond wheel is also important. In this paper, we report best grinding conditions of ultra-precision grinding machining. The grinding machining results of the form accuracy and surface roughness have been analyzed by using Form Talysurf and NanoScan.

Oblique astigmatism according to the rotation of the eye has to be removed for obtaining peripheral clear vision in ophthalmic lenses. For this reason, we calculated tangential and sagittal power using third-order approximation theory and then controlled conic constant for the difference of the two powers to converge to 0 regardless of the rotation angle of the eye. As a result, an aspherical ophthalmic lens without oblique astigmatism was designed. Also, we found optimal machining condition to the lens material using factorial design and finally fabricated the designed lens through ultra-precision machining with that condition.

The use of LED for illumination offers significant advantages, such as lower power consumption, longer lifetime and improved colour management. Sharp gradients in luminous intensity patterns of LED are commonly controlled by the use of secondary optics that are mostly axisymmetric. In the current study, we proposed LED secondary optics forming non-axisymmetric luminous intensity distribution with an extremely narrow view angle. The proposed secondary optics dramatically reduced the view angle of the LED, with a view angle ( 10º) in full width at half maximum (FWHM) in simulations. Afterward, a prototype of the proposed lens was machined by single point diamond turning (SPDT). Luminous intensity distribution of the machined lens was off by about 8º from the optical axis and maintained a view angle of 12º. The peak luminous intensity was folded more than thirty-two times. The proposed lens showed high optical performance and can be used for specialized optical applications.

In this paper, we demonstrated the machining process of a novel Light Emitting Diodes (LED) beam shaping lens, called TIR Fresnel lens, for GaN-based blue Chip Scale Packaged (CSP) LEDs. Upon achieving a precise alignment of the tool and identifying the best manufacturing condition, we have successfully fabricated a prototype of this lens on poly methyl methacrylate (PMMA) plate. The form error of the central aspheric lens was less than 1 μm deviation, and surface quality of the Fresnel facets were sufficient for Total Internal refraction without any burr or adhesion of the machined chip. Fabricated TIR Fresnel lens reduced the viewing angle of the testing CSP LED from 140° to 17.4° in FWHM. The proposed lens produced extreme compactness as well as high collimation efficiency, thereby applicable to an ultra-thin optical system.

The microstructure of as-cast Mg-xAl-2Sn alloys consists of an α-Mg matrix, a Mg17Al12 eutectic phase and a Mg2Sn phase. In as-cast alloys, the Mg17Al12 eutectic phase was located at along grain boundaries. The eutectic phase of the extruded alloys was elongated in the extrusion direction and crushed into fine particles because of deformation during hot extrusion, and the grain size was refined with an increased Al content. The maximum values of the yield strength and tensile strength were 240 MPa and 300 MPa at 9 wt.% containing Al element, respectively.

AZ31 Mg / 5083 Al clad sheet was fabricated by the hot rolling method and its mechanical properties were investigated in this study. The tensile strength and yield strength of Mg- Al clad samples were slightly higher than that of AZ31 Mg sample, resulting in high strength 5083 Al alloy. Also, in the case of the AZ31 Mg sample, tensile strength indicated different values to the rolling directions. The thickness of interface layers between magnesium and aluminum materials increased with increasing rolling temperature. The thickness of interface layer was about 1.2 μm and 1.6 μm, respectively. The difference of thickness on the interface layer with variation of rolling temperature was attributed to promote the diffusion between magnesium and aluminum materials. The Vickers hardness of Mg-Al interface layer was around 125 Hv. The interface layer composed of hard inter-metallic phases which may act a increment of Vickers hardness depending upon its thickness.

Generally, the core component of small precise optical device demands high accuracy of manufacturing processes. Although, the geometry of it is simple, the manufacturing technique to materialize is categorized as the ultra precision machining and it must be done with the specialized machines and by the trained operator. Typical examples of small precise optical device are laser printer and phone camera. The shape is very simple but required manufacturing technology is very difficult. It belongs to fine precision machining technique and needs an ultra precision machining center and an assignment researcher. Laser printers and phone cameras are representative examples in small precise optical device. Recently, small sized display device is being developed and has an inclined polygon mirror as core part. The inclined polygon mirror is different with the previous polygon mirror in the point of view that it has a variety of reflection angle. With the result that, multi lines were achieved at screen. It could not be fabricated with conventional machine for a typical polygon mirror. It was manufactured in the process of fly-cutting with Al material on which was coated electroless-Ni for enhancement of hardness. Owing to process of polishing has bad influence on reflection angle, the inclined polygon mirror must be only fabricated with fly-cutting and have surface roughness R max = 10 nm and form error R a = λ /10 ( λ = 632 nm).

GaN-based blue LEDs with various types of phosphor has been providing high brightness in lighting application with the integration of various nonimaging optical parts for controlling luminous intensity distribution. Such secondary optics, particularly in road lighting, inherently lose light flux of 15% with additional manufacturing and assembling cost. Making primary optics of LED as functional as secondary optics will cut off this additional cost and further increase the efficacy of luminaire. In this paper, we present the design procedure of LED primary optics as functional as road lighting secondary optics. The compact freeform lens has been designed with precise optical modeling of the target LED. Machining of primary optics mold comprise a determinant solution in generating specific luminous intensity distribution for road lighting. Optical performance of the primary optics had advantages of much smaller size in volume (~1/10), lumen efficacy (~93.9%).

In this study, we presented a light-emitting diode-based (LED) miniaturized optical pattern imager for slim mobile phone application. To meet volume constraints, we designed a miniaturized compact illuminating and imaging optical component. The objective was to minimize optical loss using several nano- and micro-fabrication methods. After integration into a single optical body, the prototype imager–with dimensions of 6.8 × 2.2 × 2.5 mm and a weight of 0.4 g–demonstrated clear feasibility in measuring 2D micropatterns with widths of 50 and 10 μm.

This paper presents a novel method in near-field beam shaping based on the precise optical modeling of a gallium nitride light-emitting diode (GaN LED). A Monte Carlo ray tracing simulation has been utilized to calculate the spatial photon distribution near the LED's top. By analyzing the ray data in near-field, the miniaturized lens profile is created and machined with aspherical surfaces and total internal reflection (TIR) Fresnel facets. The prototype lens reduce the viewing angle of the LED from 150 degrees to 17.5 degrees at full width half maximum (FWHM) while increasing the peak luminous intensity 10 times. The array of proposed lens with CSP LEDs exhibits feasibility of ultra thin uniform illumination in near-field.

Light-emitting diodes (LEDs) have begun to penetrate the traditional lighting industry and have left a profound impact on the illumination of thin and portable personnel telecommunication devices. Aside from this, LEDs can also be used in the design of visible optical wireless communication systems. In lighting applications, Surface Mount Device (SMD) LEDs play an important role; however, their low light flux brought about by the large viewing angle should be redistributed to increase luminescence and the communication range in communication applications. For this reason, the current study issue in this application is how to achieve a long data transmission range while dramatically reducing the overall system size for use in thin electronic products. This work presents a proposed design of an ultra-thin secondary lens for visible light communication based on white LEDs. The accurate physical modeling of a chip die and its package can make ray-trace simulation a powerful tool in predicting power distribution of the SMD LEDs in the near-field. To verify the proposed method, modeled ray data was compared with measured data. While relaxing several design constraints, the secondary light colliminator was carried out with a solution of a central refractive aspheric surface and an outer reflective surface. The optical performance of the modeled LEDs was very similar to the real one. The designed lens reduced the viewing angle of white SMD LEDs from 120° to 20° in FWHM. The proposed lens is extremely compact and efficient and is a good starting point in achieving an effective design of visible light communication between personnel telecommunication devices.

By developing a pyramid-shaped reflector, we were able to remove the optical filter that causes the decline in light efficiency in existing systems. A pyramid-type glass optical multiplexer (MUX) can be designed for beam coupling efficiency >60% in a combined module. The module was designed and optimized using CODE V, which utilizes nonlinear curve fitting numerical analysis. Based on optical design data, aspheric grinding paths were developed using ULG APS software. Tungsten carbide optical MUX mold cores were fabricated with an ultraprecision grinding machining device [ULG-100C(H3)] and optimum grinding machining of optical surface roughness ( 99.985%. A pyramid-type glass optical MUX molding technique was developed using an optical mold design, ultraprecision grinding machining technology, and a hot press molding system.

The liquid-phase sintering method was used to prepare a glass lens forming core composed of SiC-. Spark plasma sintering was used to obtain dense sintered bodies. The sintering characteristics of different SiC sources and compositions of additives were studied. Results revealed that, owing to its initial larger surface area, -SiC offers sinterability that is superior to that of -SiC. A maximum density of (theoretical density [TD] of 99.7%) was obtained in -SiC-10 wt% () sintered at without high-energy ball milling. The maximum hardness and compression stress of the sintered body reached 2870 Hv and 1110 MPa, respectively. The optimum ultra-precision machining parameters were a grinding speed of 1243 m/min, work spindle rotation rate of 100 rpm, feed rate of 0.5 mm/min, and depth of cut of . The surface roughnesses of the thus prepared final products were Ra