Integrated Automatic Optical Inspection and Image Processing Procedure for Smart Sensing in Production Lines.

An integrated automatic optical inspection (iAOI) system with a procedure was proposed for a printed circuit board (PCB) production line, in which pattern distortions and performance deviations appear with process variations. The iAOI system was demonstrated in a module comprising a camera and lens, showing improved supportiveness for commercially available hardware. The iAOI procedure was realized in a serial workflow of image registration, threshold setting, image gradient, marker alignment, and geometric transformation; furthermore, five operations with numerous functions were prepared for image processing. In addition to the system and procedure, a graphical user interface (GUI) that displays sequential image operation results with analyzed characteristics was established for simplicity. To demonstrate its effectiveness, self-complementary Archimedean spiral antenna (SCASA) samples fabricated via standard PCB fabrication and intentional pattern distortions were demonstrated. The results indicated that, compared with other existing methods, the proposed iAOI system and procedure provide unified and standard operations with efficiency, which result in scientific and unambiguous judgments on pattern quality. Furthermore, we showed that when an appropriate artificial intelligence model is ready, the electromagnetic characteristic projection for SCASAs can be simply obtained through the GUI.

Wearable and wireless performance evaluation system for sports science with an example in badminton.

Two capacitive sensing units were designed, fabricated, and embedded into two corresponding fingerstalls through microelectronic and additive manufacturing with flexible materials and ergonomic considerations in this study. The sensing units were routed to an adaptor, which in turn was routed to a transmission port (comprising a signal converter and a Bluetooth module), realizing a wearable and wireless force sensing system for sports science applications as the objective. The collected capacitive signals were converted through a preliminarily established database, indicating local force distributions on finger segments. Practical examinations with badminton actions (forehand cross-net shots) were conducted by players to show the effectiveness of the proposed system as an application example. Statistical and quantified results reflected the visual observations on valid shots (67% and 39% for the professional and amateur players, respectively) and well-controlled racket-holding attitude (19.69% and 35.31% force application difference between the first two segments of the index finger of the professional and amateur player, respectively). These proved that the proposed system outperforms existing similar systems in the market and is able to not only classify players with different skill levels but also distinguish attitude stability and controllability, showing scientific evidence in sports science for the first time.

Near-infrared imaging system for nondestructive inspection of micro-crack in wafer through dicing tape.

Detection of wafer/die crack after the wafer dicing process is important for yield rate control prior to packaging. The traditional approach of microscopic examination is done after the dies are stripped from the dicing tape, and further crack propagation could result from this pick-and-place process. An on-tape crack inspection technique is proposed in this paper so that the crack from the dicing process can be clearly identified. The issues of seeing through the silicon substrate and the scattering at the dicing tape have been resolved, respectively, using a near-infrared wavelength of 1100 nm for illumination and using a feeding index matching liquid for filling the rough surface of the tape. Both the illumination and imaging optics of the inspection system have been designed and simulated with a ray-tracing program, and the prototype demonstrates the ability of seeing through the silicon substrate and dicing tape as well as detecting micro-crack down to 1.25 µm, whose resolution is sufficient for most applications of die crack inspection.

Thermoresistive strain sensor and positioning method for roll-to-roll processes.

This study uses the Joule heating effect-generated temperature difference to monitor in real-time and localize both compressive and tensile strains for the polymer substrates used in the roll-to-roll process. A serpentine gold (Au) line was patterned on a polyethylenenaphthalate (PEN) substrate to form the strain sensor based on thermoresistive behavior. This strain sensor was then subjected to either current or voltage to induce the Joule heating effect on the Au resistor. An infrared (IR) detector was used to monitor the strain-induced temperature difference on the Au and PEN surfaces and the minimal detectable bending radius was 0.9 mm with a gauge factor (GF) of 1.46. The proposed design eliminates the judgment ambiguity from conventional resistive strain sensors where resistance is the only physical quantity monitored. This study precisely and successfully indicated the local strain quantitatively and qualitatively with complete simulations and measurements.

Post-lithography pattern modification and its application to a tunable wire grid polarizer.

This study reports a simple and cost-effective post-lithography solution for reducing the characteristic dimensions of structures on the nanometer scale using an external mechanical force without any modification of the existing exposure system. In particular, this study presents a tunable aluminum wire grid polarizer (WGP) made by a laser interference lithography and i-line (365 nm) exposure setup on polyethylene naphthalate. The WGP achieves a 58% maximum linewidth shrinkage of the metal nanowire on the polymer substrate, and further improved the polarization extinction ratio by 83% with a defined operation window and optimized strain. The simulations in this study prove the rise of the extinction ratio with the modulation of the WGP pattern. Physical evidence explains the fall of the extinction ratio for both the increase of the metal crack volume and the delaminated randomly oriented fall-on fragments under extensive operation.

A high sensitivity three-dimensional-shape sensing patch prepared by lithography and inkjet printing.

A process combining conventional photolithography and a novel inkjet printing method for the manufacture of high sensitivity three-dimensional-shape (3DS) sensing patches was proposed and demonstrated. The supporting curvature ranges from 1.41 to 6.24 × 10(-2) mm(-1) and the sensing patch has a thickness of less than 130 µm and 20 × 20 mm(2) dimensions. A complete finite element method (FEM) model with simulation results was calculated and performed based on the buckling of columns and the deflection equation. The results show high compatibility of the drop-on-demand (DOD) inkjet printing with photolithography and the interferometer design also supports bi-directional detection of deformation. The 3DS sensing patch can be operated remotely without any power consumption. It provides a novel and alternative option compared with other optical curvature sensors.