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This study establishes the polymer-stacking and metal-electroplating processes on Si-substrate to implement a flexible and transparent substrate with alignment mesa, distributed though-hole-vias, and multi-layer electrical routings. This process is especially useful for 3D integration of micro optical components on flexible substrate. The integrated chips can be further protected and sealed by an additional parylene coating. More micro-optical components can also be vertically integrated by additional polymer molding. To demonstrate the feasibility of this approach, LED chips are bonded and sealed in flexible substrate, and the polymer microlens is further integrated with the lighting chips using molding process. The lighting of packaged LED chips is demonstrated in both air and water.

This study presents a novel thermal isolation component “polymer joint” to reduce the current and heat flow (by conduction) between micro thermal actuators. An optical stage consisted of V-beam thermal actuators for optical-tracking and thermal-driven focal-length tunable micro polymer lens for optical-focusing is employed to demonstrate the present concept. To overcome the thermal coupling of these two actuators by heat-conduction, the two components fabricated by SOI wafer (Si∼150W/m-k) are connected by the low thermal conductivity joints (polymer∼0.2W/m-k). The displacement provides by the V-beam actuator is about ±13µm. The temperature difference is about 80°C measurement by infrascope. The variation of micro lens radius of curvature is about 1%.

This study implements a novel lighting chip with tunable radiation pattern. The lighting chip consists of polymer-dispersed liquid crystal (PDLC) microprism array, LED, and Si-carrier. By integrating the characteristics of microprism and the scattering/transmitting modes of PDLC, the PDLC-microprism enables the tuning of radiation pattern when applying voltage. The lighting chip with PDLC-microprism has the following advantages, (1) no moving parts are required to tune the radiation pattern, (2) the shape of PDLC-microprism array can be easily changed by molding processes, and (3) the fabrication and packaging are performed at low temperature and the damage to PDLC is prevented.

This research demonstrates a solid microlens formation technology to realize the plano-convex and biconvex lens in multi-phase liquid ambiance. The liquid polymer droplet is shaped by surface tension equilibrium in liquid-liquid and liquid-solid ambience. The radii of curvature of the lens are easily controlled by varying the liquid ambiance. The microlens is implemented using a commercial liquid-polymer dispensing system, and its dimensions can be precisely controlled. The microlens can either be a discrete optical component, or directly integrated with MEMS structures during the process to form a SiOB (silicon-optical-bench). To date, the plano-convex (X=1) microlens with radius ranging 0.35mm∼2mm and surface roughness ≪10nm are fabricated, and the biconvex lens (0≪X≪1) is also demonstrated.

This study presents a novel microlens formation technology to implement a polymer ball lens in liquid medium. The highly symmetric ball lens is achieved due to the lower gravity influence in liquid. The microlens' diameter is controlled by the volume of the dispensed polymer. Moreover, it is easy to dispense, form, and align the liquid-phase polymer microlens with MEMS structures while processing in liquid. Thus, the microlens can either be a discrete optical component, or directly integrated with MEMS structures during the process to form a SiOB (silicon-optical-bench). To date, ball lenses with diameter ranging 200?m~600?m and surface roughness ≪10nm are fabricated. A typical sphericity is 8.6?m for a 525?m diameter ball lens. The integration of such polymer micro ball lens on SiOB is also demonstrated.

This study presents a novel lens formation technology to implement a 3D polymer lens in buffer liquid. The integration of such 3D polymer lens on SiOB and the application for barcode scanner are also demonstrated.

A MEMS batch assembly process for fabricating small form factor optical pickup head is proposed to minimize the complexity of assembly. Electrical and optical components are sealed in a chamber. A silicon optical bench with a packaged laser diode and crystalline-plane mirrors is demonstrated.

This research demonstrates three novel concave-based micro optical components. A double-concave (DCV) lens is realized by a simple polymer dispensing and sucking process. The DCV component consists of a high-aspect-ratio lens frame structure and dispensed UV-curable polymer lens. Moreover, this study further employs the process for DCV to implement the concave-mirror and the doublet. The measurements show a typical DCV (made of NOA63 polymer) has negative focal lengths of -1.42 mm (for 632.8 nm red-laser) and -1.17 mm (for 473 nm blue-laser), and a typical concave mirror has a focal-length of 3.28mm. The NOA63/PDMS doublet is also demonstrated.

Hepatocellular carcinoma (HCC) is the leading cause of death in male cancer patients in Asia. PPARγ exhibited an inhibitory role in hepatocarcinogenesis in vitro and in vivo. Recently, it was found that honokiol functions not only as a RXR agonist but also a PPARγ agonist, and is capable of potentiating the activation of PPARγ in the presence of PPARγ agonist rosiglitazone in HLE human hepatoma cells. It also has been reported that honokiol exerts inhibitory effects on the growth and migration in hepatoma cells. However, whether PPARγ overexpression modulates the honokiol-induced growth inhibition in hepatoma cells is not known. Firstly, we examined the expression of PPARγ in tumor samples from 83 HCC patients by immunohistochemical staining. Our results showed that 53 samples had no PPARγ and the clinical parameters including tumor number, stages, and macroscopic vascular invasion (MVI) showed significant negative correlation with PPARγ expression. However, the expression of PPARγ was not associated with disease free survival or overall survival of patients with HCC. Using PPARγ overexpressed SK-Hep1 cells (SK-Hep1-PPARγ) for in vitro analyses, we found that 40 μM honokiol treatment of SK-Hep1-PPARγ cells induced a 20% increase of growth inhibition at 48 hour as compared to vector control cells by MTT assay. This corresponded well with the 15% increase in G0/G1 phase after honokiol treatment at 24 hour compared to vector control cells. In addition, honokiol treatment resulted in decreased cyclin D1, increased p21 and KLF4 expressions in SK-Hep1-PPARγ cells. Moreover, miRNA array analyses showed that increased expression of miR-222, let-7i, miR-628-3p and miR-664 as well as decreased miR-1291, miR184 and miR1249 were observed in SK-Hep1-PPARγ cells. In conclusion, PPARγ is not only a biomarker for prognosis of patients with HCC but also play an important role in the honokiol-induced growth inhibition of hepatoma cells. The functional importance of PPARγ regulated miRNA is currently under further investigation. Citation Format: Chin-Wen Chi, Hui-Tzu Hsu, Jia-Dong Hou, Chih-Chun Lee, Ying-Ju Kuo, Hsin-Chen Lee, Cheng-Yuan Hsia. Study of the functional importance of PPARγ in honokiol-induced apoptosis of hepatoma cells. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3612. doi:10.1158/1538-7445.AM2015-3612

This study presents the approach to implement the electrostatically-controlled thin film optical filter by using a nanoporous anodic aluminum oxide (np-AAO) layer as the key suspended micro structure. The bi-stable optical filter operates in the visible spectral range. In this work, the presented bi-stable optical filter has averaged reflectivity of 60%, and the central wavelengths are 580 and 690 nm respectively for on and off states. The presented np-AAO layer offers the following merits for the thin film optical filter: (1) material properties of np-AAO film, such as refractive index, elastic modulus and dielectric constant, can be easily changed by a low temperature pore-widening process, (2) in-use stiction of the suspended np-AAO structure can be reduced by the small contact area of nanoporous textures, (3) driving (pull-in) voltage can be reduced due to a large dielectric constant (eAAO is 7.05) and small stiffness of np-AAO film and (4) dielectric charging can be reduced by the np-AAO material; thus the offset voltage is small. The study reports the design, fabrication and experimental results of the bi-stable optical filter to demonstrate the advantages of the presented device. The np-AAO material also has the potential for applications of other electrostatic drive micro devices.

Bile leakage after hepatic resection can cause septic complications and mortality. This study evaluated the risk factors associated with postoperative bile leakage in hepatocellular carcinoma patients.Between July 1991 and December 2000, 605 consecutive hepatocellular carcinoma patients who underwent hepatic resection were enrolled. Risk factors associated with postoperative bile leakage were examined, with 38 clinicopathological variables being analyzed. Data were collected prospectively and analyzed retrospectively.Bile leakage developed in 35 (5.8%) of 605 patients. When compared with patients without bile leakage, those with bile leakage had higher risk for concomitant morbidities (54.3% vs. 29.2%, P=0.002), postoperative mortality (8.6% vs. 2.6%, P=0.045), and a prolonged postoperative hospital stay (29 days vs. 14 days, P0.001). The bile leakage rate of centrally located tumors (9.4%) was significantly higher than that of peripherally located tumors (3.5%; P=0.002). The bile leakage rate of patients with preoperative chemoembolization (13.8%) was significantly higher than those without chemoembolization (4.9%; P=0.004). Stepwise logistic regression analysis identified preoperative chemoembolization (OR=3.274, P=0.005) and tumor(s) being centrally located (OR=2.927, P=0.003) as the independent predictors of development of bile leakage.For HCC patients, preoperative chemoembolization and tumor(s) with central location are risk factors for post-hepatectomy bile leakage. As bile leakage can cause septic complications and liver failure, careful surgical procedures and use of preventive measures are necessary, especially in patients with high risk factors.

This study implements a compact solid-state lighting chip with changeable illumination map as well as radiation pattern. The lighting chip consists of a microprism array, light-emitting diode (LED) chip and Si carrier. The polydimethylsiloxane (PDMS) and polymer-dispersed liquid crystal (PDLC) layers are respectively employed to implement the passive and active microprism arrays. The specific radiation pattern can be defined by the shape of the passive PDMS-microprism. Moreover, by using the scattering and transmitting modes of the PDLC layer, the PDLC-microprism enables the changing of light shaping by applying voltage. Thus, the radiation pattern can be changed by the driving voltage on the PDLC layer, and the deformable and movable micro optical components are not required. This study has established the low-temperature fabrication and packaging processes to realize the lighting chip, and the damage of the PDMS and PDLC material is prevented. Typical dimensions of the PDMS lighting chip are 5 mm wide, 6 mm long and 1 mm thick, and The PDLC lighting chip is 550 µm thick. The measurement results show that the PDMS-microprism array can change the radiation pattern from a 70° half-maximum viewing angle to 52° and 40° half-maximum viewing angles on two orthogonal axes. In addition, the PDLC-microprism array can change the radiation pattern from 51° and 43° half-maximum viewing angles at 0 V (i.e. scattering mode) to 48° and 33° half-maximum viewing angles at 100 V (i.e. transmitting mode).

This paper presents a two-phase liquid micro lens formation technology to implement a polymer micro ball lens. A UV-curable polymer is dispensed into a buffer liquid to form the ball lens. The buffer liquid provides a gravity-free condition so that the ball lens has a highly symmetric shape. The diameter of the ball lens is controlled by the volume of the dispensed polymer. This technology implements either a discrete optical component, or a ball lens integrated with a MEMS (micro electrical mechanical system) structure to form a SiOB (silicon optical bench). To demonstrate the feasibility of this study, ball lenses with diameters ranging from 200 to 600 µm and root mean square (RMS) surface roughness of about 10 nm are fabricated using a commercial UV-curable polymer. The average roundness of a 550 µm diameter ball lens observed from different angles is 3.3 ± 0.4 µm. The peak-to-valley and RMS wavefront errors of a 550 µm diameter ball lens measured by a Mach–Zehnder interferometer are 0.3744 waves (237 nm) and 0.0766 waves (48 nm), respectively. The measured back focal length is about 99 µm, and the associated effective focal length is about 351 µm. The integration of such polymer micro ball lenses with suspended micromachined Si3N4 structures to form the SiOB is also demonstrated.