Shih-Feng Tseng

The Mixed Processing Models Development Of Thermal Fracture And Laser Ablation On Glass Substrate

As the industries of cell phone and LCD TV were vigorously flourishing and the manufacturing requirements for LCD glass substrate were getting higher, the thermal fracture cutting technology (TFCT) has progressively become the main technology for LCD glass substrate cutting. Due to using laser as the heat source, the TFCT has many advantages, such as uniform heating, small heat effect zone, and high cutting speed, smooth cutting surface and low residual stress, etc. Moreover, a general laser ablation processing or traditional diamond wheel cutting does not have the last two advantages. The article presents a mixed processing of glass substrate, which consists of TFCT and laser ablation mechanisms, and how to enhance the cutting speed with little ablation laser energy. In this study, a 10W Nd:YAG laser and a 40W CO2 laser are used as the heat source of TFCT and laser ablation processing, respectively. The result indicates that the speed of the mixed processing is more than twice the speed of TFCT. Furtherm...

A Study on Thermal Fracture Processing Models Applied to Glass Substrate Cutting

Thermal fracture-cutting technology (TFCT) for brittle materials has become the main technology for LCD glass substrate cutting to meet the low residual thermal stresses requirement. Based on the thermal weight function principle of fracture mechanics, this paper presents thermal weight function distributions for the mode-I and mode-II fracture model, and the fracture phenomenon under a variety of cutting paths, such as tilt crack, split crack, twist crack, and local buckling.

Surface Formation of Nano- / Micro- Structures on Titanium Alloy Composites using Picosecond Laser Scanning Technology

This study reports on the development of picosecond laser system to titanium alloy surface treatment applications. In the picosecond laser-scanning system, that is based on the fiber-optics laser source and integrated with a designed optics / optical machine design and control technology of scanning system. To analyze the laser material interaction, the laser fluence, pulse repetition frequency of laser source, position of focused points, scan speed and pulse duration were adjusted. After laser surface treatment, the surface roughness and surface morphologies of treated surface were evaluated by using a field emission scanning electron microscope. Moreover, the contact angle measurement was used to analyze the hydrophilic and hydrophobic properties of the treatment surface with micro/ nanostructures.

Characteristics of Graphene Oxide Films Reduced by Using an Atmospheric Plasma System

The chemical oxidation method can be used to mass-produce graphene oxides (GOs) from highly oriented pyrolytic graphite. However, numerous oxygen-containing functional groups (hydroxyl, epoxy, carbonyl, etc.) exist in typical GO surfaces, resulting in serious electrical losses. Hence, GO must be processed into reduced graphene oxide (rGO) by the removal of most of the oxygen-containing functional groups. This research concentrates on the reduction efficiency of GO films that are manufactured using atmospheric-pressure and continuous plasma irradiation. Before and after sessions of plasma irradiation with various irradiation times, shelters, and working distances, the surface, physical, and electrical characteristics of homemade GO and rGO films are measured and analyzed. Experimental results showed that the sheet resistance values of rGO films with silicon or quartz shelters were markedly lower than those of GO films because the rGO films were mostly deprived of oxygen-containing functional groups. The lowest sheet resistance value and the largest carbon-to-oxygen ratio of typical rGO films were approximately 90 Ω/sq and 1.522, respectively. The intensity of the C–O bond peak in typical rGO films was significantly lower than that in GO films. Moreover, the intensity of the C–C bond peak in typical rGO films was considerably higher than that in GO films.

Process of opto-mechanical design and assembly for reflective mirror subsystem of lithographic projection lens

Considering the system performance of the projection lens, not only surface quality of the optics shall be concerned, misalignment between each optics and the wavefront distortion contributed by the mounting stress and gravity are also the factors degraded the optical performance. This article introduces the opto-mechanical design and stress-free assembly process of the reflective mirror subsystem with 300 mm in outer diameter of an I-line lithographic projection lens. The flexure with mounting position pass through the center gravity of the mirror can be adopted as supporting mechanism to prevent the gravity distortion. The distortion due to temperature difference can be avoided by adopting CLERACREAM®-Z glass ceramic and INVAR for material of reflective mirror and supporting flexure respectively. The adjustment mechanism of the mirror subsystem integrates the concepts of Kinematic and exact constraint to provide six degrees of freedom (6DoF) of posture adjustment of the mirror. Furthermore, the assembly process of the flexure which minimizes the mounting stress on the mirror is presented. In the end of this article, interferometric performance test of the reflective mirror after opto-mechanical assembly compared with the measurement result in manufacturing stage is also presented. With the proposed opto-mechanical design and stress-free mounting process of the mirror, the surface distortion contributed by the amount of mounting stress and gravity effect is less than P-V 0.02 wave @632.8 nm.

Absolute measurement method for correction of low-spatial frequency surface figures of aspherics

Abstract. An absolute measurement method involving a computer-generated hologram to facilitate the identification of manufacturing form errors and mounting- and gravity-induced deformations of a 300-mm aspheric mirror is proposed. In this method, the frequency and magnitude of the curve graph plotted from each Zernike coefficient obtained by rotating the mirror with various orientations about optical axis were adopted to distinguish the nonrotationally symmetric aberration. In addition, the random ball test was used to calibrate the rotationally symmetric aberration (spherical aberration). The measured absolute surface figure revealed that a highly accurate aspheric surface with a peak-to-valley value of 1/8 wave at 632.8 nm was realized after the surface figure was corrected using the reconstructed error map.

Inspection of Laser Ablated Transparent Conductive Oxide Thin Films by a Multifunction Optical Measurement System

In recent years, laser ablation method has been increasingly used in the touch panel industry. Touch panel devices are produced by applying laser ablation process on transparent conductive oxide (TCO) thin films coated on glass substrates. The pattern and the surface profile of the transparent conductive layer on glass substrates after laser ablation are crucial on the quality of the touch panel. Therefore, a self-assembled multifunction optical measurement system was employed to investigate the details of the surface of the test specimen of the TCO thin films after ablation. The system integrates both optical microscope and white-light scanning interferometer to inspect the specimen under the same field of view. The transparency of the test specimen was inspected by the optical microscope to examine the uniformity of the gray levels throughout the ablated region. The depth of the ablated thin films and whether the thin films are fully cut can be determined from the surface profile obtained from the white-light scanning interferometer. Based on the aforementioned experimental results, the self-assembled multifunction optical measurement system is full of potential to be used to determine the manufacturing parameters in laser ablation process.

Effects of UV laser milling parameters on the profile cutting of Gorilla glass substrates

The purposes of this study were to develop a high-speed milling system combined with an ablation path of the parallel lines and to investigate the cut quality on the glass substrates conducted by a nanosecond pulsed Nd:YVO4 laser (λ:355 nm). Experimental specimens were commercial Corning Gorilla glass with a thickness of 800 μm. Laser milling parameters including the laser fluence, number of milling pass, and scan speed of galvanometers along the processing path were adjusted for the profile cutting of the glass substrates. The laser milled depth, surface morphology, and surface roughness of the glass substrates after laser milling were measured by a 3D confocal laser scanning microscope. Experimental results showed that the milled depth outstandingly increased as increasing the laser fluence and the number of milling pass or decreasing the scan speed of galvanometers. The milled depths averagely increased from 38 μm to 107 μm when the scan speed of galvanometers decreased from 1500 mm/s to 300 mm/s with the laser fluence of 52 J/cm2 in a one-cycle milling process. Moreover, the milled depths averagely increased from 107 μm to 185 μm when the laser fluence decreased from 54 J/cm2 to 95 J/cm2 with the scan speed of galvanometers of 300 mm/s. When the number of milling pass increased to 5 with the laser fluences of 95 J/cm2 and scan speed of 300 mm/s, the Gorilla glass substrate was cut through a square hole. The edge of milled hollow square structures on the glass substrate had few of micro cracks, square angles, and steep and oblique walls around the milled boundaries as increasing the number of milling pass. In addition, the value of surface roughness increased with increasing the numbers of milling pass.

Parameters optimization of laser electrode patterning on ITO/glass using multi-performance characteristics analysis

The objective of this study was to obtain the optimal parameters for laser electrode patterning of indium-tinoxide (ITO) films coated on soda lime glass substrates; the parameters were determined through grey relational analysis. The electrode patterning parameters affecting the sheet resistance and optical transmittance of the film include the laser power, pulse repetition frequency, pulse duration, and focus point position. Multiple performance characteristics associated with the sheet resistance and optical transmittance were investigated by conducting experiments. An infrared (1064 nm) laser system was used to directly fabricate electrode patterns on ITO films, and the characteristics of the patterned films were systematically analyzed using an ultraviolet-visible-near-infrared spectrophotometer and a four-point probe instrument. The data obtained from the experiments were analyzed to optimize the laser patterning parameters correlated with multiple performance characteristics.

Aligning and measuring the curvature and thickness of high-precision lens

The radius of curvature is one of the most important specifications for spherical optics [1]. There are several methods and devices currently on the market that can be used to measure it, including optical level, non-contact laser interferometer (Interferometer), a probe-contact profiler (Profilometer), the centering machine and three-point contact ball diameter meter (Spherometer). The amount that can be measured with a radius of curvature of the lens aperture range depends on the interferometer standard lens f / number and lens of R / number (radius of curvature divided by the clear aperture of the spherical surface ratio between them). Unfortunately, for lens with diameter greater than 300 mm, the device is limited by the size of the holding fixture lenses or space. This paper aims to provide a novel surface contour detection method and machine, named “CMM spherometry by probe compensation,” to measure the radius and thickness of the curvature of the optical surface by a coordinate measurement machine (CMM). In order to obtain more accurate optimization results, we used probe and temperature compensation to discuss the effect. The trace samples and the measurement results of CMM and the centering machine, which has top and bottom autocollimators, are compared.