Microlenses and microlens arrays formed on a glass plate by use of a CO_2 laser

Abstract

Microlenses and microlens arrays were formed directly on a surface of a glass plate by use of a CO(2) laser. When the surface of a glass plate is heated locally to a working point of the glass material by use of a focused CO(2) laser beam, it tends to become a hyperboloid owing to surface tension, which results in a microlens. A profile of the microlens was measured with an ultrahigh accurate three-dimensional profilometer (Model UA3P, Matsusita Electric Industrial Company Ltd.) that utilizes a specially designed atomic force microscope. An intensity profile and a spot diameter at the focus of the microlens were measured with a microscope and a CCD system utilizing a He-Ne laser as a light source. The focused spot FWHM diameter of 1.35 mum was obtained, and the modulation transfer function was derived from the spot profile. Microlens arrays were also fabricated and characterized.

Laser micro-fabrication of concave, low-roughness features in silica

“…1,2 Owing to the surface-minimizing effect of the surface tension, melting of large-scale domains which penetrate considerably into the volume will result in the formation of convex structures. While this behaviour has been successfully employed for the fabrication of convex micro-optical structures, [3][4][5][6] it is undesired in the context of surface polishing. At higher intensities, material removal by evaporation becomes important.…”

Comparing glass and plastic refractive microlenses fabricated with different technologies

“…Various fabrication techniques have been proposed for this purpose [2]; among these are photothermal expansion [3], ion exchange [4], CO 2 laser irradiation [5] and reactive ion etching [6]. More recently fabrication techniques of microoptical components in new lightweight optical materials have become the research topic of interest.…”

Fabrication of Microlens Array Using Photoresist Thermal Reflow

“…포토 레지스트를 사용한 reflow 방법, [3][4] 건식 에칭 방법, [5] CO2 가 스 레이저를 사용한 유리 표면 가공 방법, [6] 용해된 유리의 표면 장력을 이용한 방법, [7] 폴리머의 레이저 증착과 이온빔 가공법, [8] 잉크젯 기술, [9] PR 가열법, [10] 그레이-스케일 마스 법 [11] 등 매우 다양하게 제작할 수 있다. [12] 본 논문에서는 그 중 포토레지스트 [13] 를 사용한 thermal reflow 방법을 이용 하여 MLA 시트를 제작하였고, 최적의 노광조건과 reflow 온 도와 시간을 구하였다.…”