• Title/Summary/Keyword: lens process

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Micro replication quality of Fresnel lens using UV imprinting process (UV 임프린팅을 통한 프레넬 렌즈 제작 시 미세 복제 특성에 관한 연구)

  • Lim,, Ji-Seok;Kim, Byung-Wook;Kang, Shin-Ill
    • Transactions of the Society of Information Storage Systems
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    • v.6 no.1
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    • pp.37-40
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    • 2010
  • Fresnel lens is a kind of refractive optical lens with various advantages. It has nearly flat shaped optical lens that has small mass. Fresnel lens has number of applications in the compact optical systems. Recently, demands of high quality Fresnel lens for small size optical systems such as illumination units, compact imaging systems, display units, information storage systems, optical detecting units had increased rapidly. Conventional manufacturing process of high quality Fresnel lens is direct machining. However, it is not suitable for mass production because of high cost and long cycle time. Replication method can provide cost effective mass production process. However, there are various issues about replication of Fresnel lens. Fresnel lens has number of sharp blade shape prism. In the replication process, this blade shape causes defects that can affect optical efficiency. In this study, replication processes; injection molding process and UV imprinting process, were developed and evaluated using Fresnel lens that has maximum pattern height of $250\;{\mu}m$ and aspect ratio of 1.5.

Finite Element Analysis of Glass Lens Forming Process Using Open Die (개방형 금형을 이용한 유리 렌즈 성형 해석)

  • 나진욱;임성한;전병희;오수익
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2003.05a
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    • pp.143-147
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    • 2003
  • Despite of outstanding optical performance of glass lens, glass lens have not been widely used because of poor productivity and high cost due to manufacturing process i.e. grinding, polishing. However, press-forming method of glass lens overcomes this disadvantage because of mass production. When glass lens is produced by press-forming method using closed die, it is needed that the volume of glass lens preform precisely measured in order to prevent incomplete products and to increase in life of die. The present paper shows the shortcoming of forming process with closed die, and performs FEM simulation of forming process with open die in order to overcome this shortcoming. The design parameter of open die is selected in standard of assembly with optical module and maintenance of optical performance. FEM simulation is carried out with selected parameter of open die and two basic preform. According to distribution of effective strain in glass lens, optical property of glass lens formed at each set of die and preform is compared.

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A Study on the Effect of Shrinkage on Lens Deformation in Optical Lens Manufacturing Process Using Thermosetting Resin Material (열경화성 수지 재료를 이용한 광학 렌즈 제조공정에서 렌즈 변형에 대한 수축률이 영향에 관한 연구)

  • Park, Si Hwan
    • Design & Manufacturing
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    • v.16 no.3
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    • pp.9-15
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    • 2022
  • In order to reduce the manufacturing costs of the glass lens, it is necessary to manufacture a lens using a UV curable resin or a thermosetting resin, which is a curable material, in order to replace a glass lens. In the case of forming a lens using a thermosetting material, it is necessary to form several lenses at once using the wafer-level lens manufacturing technologies due to the long curing time of the material. When a lens is manufactured using a curable material, an error in the shape of the lens due to the shrinkage of the material during the curing process is an important cause of defects. The major factors for these shape errors and deformations are the shrinkage and the change of mechanical properties in the process of changing from a liquid material during curing to a solid state after complete curing. Therefore, it is necessary to understand the curing process of the material and to examine the shrinkage rate and change of physical properties according to the degree cure. In addition, it is necessary to proceed with CAE for lens molding using these and to review problems in lens manufacturing in advance. In this study, the viscoelastic properties of the material were measured during the curing process using a rheometer. Using the results, Rheological investigation of cure kinetics was performed. At the same time, The shrinkage of the material was measured and simple mathematical models were created. And using the results, the molding process of a single lens was analyzed using Comsol, a commercial S/W. In addition, the experiment was conducted to compare and verify the CAE results. As a result, it was confirmed that the shrinkage rate of the material had a great influence on the shape precision of the final product.

Micro-replication quality of Fresnel Lens in UV micro-replication process (프레넬 렌즈 UV 미세복제 공정에서의 전사특성에 관한 연구)

  • Lim J.;Lee N.;Kim S.;Kang S.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2005.10a
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    • pp.79-82
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    • 2005
  • Fresnel lens has number of applications in the optical systems because of its advantages. It is nearly flat lens that has small weight. It is conventionally used in lighthouse beacons, condensing unit of overhead projector and etc. Recently, demands of small size optical systems such as display units, information storage systems, optical detecting units had increased. Conventional manufacturing process of high quality Fresnel lens is direct machining. But it is not suitable for mass production because of high cost and long cycle time. Replication process is more suitable for mass production. But the Fresnel lens has number of sharp blade shape prism. In the replication process, this blade shape causes defects that can affect optical efficiency. In this study, replication process of blade shape pattern that has maximum height of $280{\mu}m$, aspect ratio 1.4 for Fresnel lens application.

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Finite Element Analysis of Glass Lens Forming Process Using Open Die (개방형 금형을 이용한 유리 렌즈 성형 해석)

  • 나진욱;임성한;오수익;전병희
    • Transactions of Materials Processing
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    • v.12 no.4
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    • pp.296-301
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    • 2003
  • Though a glass tens has outstanding optical performance, it has not been widely used because manufacturing process shows poor productivity and high cost. However, press-forming method of glass lens overcomes these disadvantages with mass production. When glass lens is produced by press-forming method using closed die, it is needed that the volume of glass lens preform is precisely measured in order to prevent incomplete products and to increase in life of die. The present. paper shows the shortcoming of forming process with closed die, and performs FEM simulation of forming process with open die in order to overcome this shortcoming. The design parameters of open die are selected on the basis of assembly with optical module and maintenance of optical performance. FEM simulation is carried out with selected parameter of open die and two basic preform. According to distribution of effective strain in glass lens, optical property of glass lens formed at each set of die and preform is compared.

A Study on Key Parameters and Characteristics in the Manufacturing Process of the Dual Pickup Objective Lens (Dual Pickup 대물렌즈의 생산을 위한 주요 Parameter 및 특성에 관한 연구)

  • Woo, Sun-Hee;Lee, Dong-Ju
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.16 no.3
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    • pp.117-124
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    • 2007
  • In order to operate CD and DVD compatibly in a pickup system, the objective lens comprise diffractive optical element(DOE) zone and aspheric curvature on its lens surface. The DOE objective lens is effective to simplify this dual-purpose pickup system of the 655nm and 785nm wavelength by using only one lens, but requires more precision manufacturing process and system due to the complicated shape. This paper presents the overall manufacturing process of this objective lens and describes main parameters in each process, for the correction of the aspheric surface in its core, the shrinkage compensation after injection molding, and the uniformity compensation by adjusting molding conditions.

A Preliminary Study on the Lamination Characteristics of Inconel 718 Superalloy on S45C Structural Steel using LENS Process (LENS 공정을 이용한 Inconel 718 초합금의 S45C 구조용강 위 적층 특성 고찰에 관한 기초 연구)

  • Kim, Hyun-Sik;Lee, Hyub;Ahn, Dong-Gyu
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.20 no.1
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    • pp.16-24
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    • 2021
  • A laser-engineered net shaping (LENS) process is a representative directed energy deposition process. Deposition characteristics of the LENS process are greatly dependent on the process parameters. The present paper preliminarily investigates deposition characteristics of Inconel 718 superalloy on S45C structural steel using a LENS process. The influence of process parameters, including the laser power and powder feed rate, on the characteristics of the bead formation and the dilution in the vicinity of the deposited region is examined through repeated experiments. A processing map and feasible deposition conditions are estimated from viewpoints of the aspect ratio, defect formation, and the dilution rate of the deposited bead. Finally, an appropriate deposition condition considering side angle, deposition ratio, and buy-to-fly (BTF) is predicted.

A Study on the Thermal Stresses of the Glass Lens Mold Using in Progressive GMP Process (순차이송 GMP 방식용 유리렌즈 금형의 열응력에 관한 연구)

  • Chang, S.H.;Lee, Y.M.;Shin, G.H.;Yoon, G.S.;Jung, W.C.;Jung, T.S.;Heo, Y.M.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2007.10a
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    • pp.289-292
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    • 2007
  • To prevent the damage of glass lens molds and deterioration of glass lenses using in progressive GMP process, a thermal stress and a deformation of the glass lens molds at forming temperature should be considered in the design step. In this study, as a fundamental study to develop a multi cavity mold used in an aspheric glass lens molding, a heat transfer and a thermal stress analysis were carried out for the case of one cavity glass lens mold used in progressive GMP process. Finally, using analysis results, we estimated the thermal stress in a glass lens mold and predicted a modified height of guide ring that determines the forming height of a glass lens.

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Effect of Injection Molding Conditions of Effective Surface Properties of F-theta Lens (사출 성형 조건이 에프세타 렌즈의 유효면 특성에 미치는 영향)

  • Park, Yong-Woo;Zhang, Qi;Moon, Seong-Min;Lyu, Sung-Ki
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.20 no.9
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    • pp.20-27
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    • 2021
  • The effective surface of lens was studied for injection molding process and to enable mass production of f-theta lens, which is the primary component of laser printers and laser scanning systems. Injection molding is an optimal method if f-theta lens is frequently used for the mass production of plastic lenses as an aspherical lens that requires ultra-precision. A uniform injection molding system should be maintained to produce high quality lenses. Additionally, to maintain these injection molding systems, various factors such as pressure, speed, temperature, mold and cooling should be considered. However, a lens with the optical characteristics of an f-theta lens can be obtained. The effects of melting and cooling of plastic resin on the effective surface of f-theta lenses and the numerous factors that affect the injection molding process were studied.

Study on the Aspheric Glass Lens Forming Simulation in the Progressive GMP process (순차이송 GMP 공정에서의 비구면 유리렌즈 성형 해석에 관한 연구)

  • Chang, S.H.;Gang, J.J.;Shin, K.H.;Jung, W.C.;Heo, Y.M.;Jung, T.S.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2008.05a
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    • pp.539-542
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    • 2008
  • Recently, GMP(Glass Molding Press) process is mainly used to produce aspheric glass lenses. Because glass lens is heated at high temperature above Ty (yielding point) for forming glass, the quality of aspheric glass lens is deteriorated by residual stresses which are generated in a aspheric glass lens after forming. Before this study, as a fundamental study to develop forming conditions for progressive GMP process, compression, strain relaxation and thermal conductivity tests were carried out to obtain the visco-rigid plastic, the visco-elastic and thermal properties of K-PBK40 which is newly developed and applied for precision molding glass material, In this study, using the experimental results we obtained, a glass lens forming simulation in progressive GMP process was carried out and we could forecast the shape of deformed glass lenses and residual stresses contribution in the structure of deformed glass lenses after forming.

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