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Light field imaging, which captures spatio-angular information of incident light on image sensor, enables many interesting applications like image refocusing and augmented reality. However, due to the limited sensor resolution, a trade-off exists between the spatial and angular resolution. To increase the angular resolution, view synthesis techniques have been adopted to generate new views from existing views. However, traditional learning-based view synthesis mainly considers the image quality of each view of the light field and neglects the quality of the refocused images. In this paper, we propose a new loss function called refocused image error (RIE) to address the issue. The main idea is that the image quality of the synthesized light field should be optimized in the refocused image domain because it is where the light field is perceived. We analyze the behavior of RIL in the spectral domain and test the performance of our approach against previous approaches on both real and software-rendered light field datasets using objective assessment metrics such as MSE, MAE, PSNR, SSIM, and GMSD. Experimental results show that the light field generated by our method results in better refocused images than previous methods., Accepted to IEEE Transactions on Image Processing

A programmable ultraviolet light-emitting diode (UVLED) array with a transfer lens forms an adjustable intensity distribution upon a mask, whether for the uniform distribution or variable distribution for compensate wavefront error introduced by the lithographic lens, so as to fabricate an aberration-free pattern on a wafer. The collimating and aligning all rays in one aperture lens with a N × N two-dimensional UVLED array is designed and fabricated by integrating with lithographic lens to form aberration-free smallest linewidth in integrated circuit wafer. Our work provides a transfer lens for the UVLED array to manipulate the intensity distribution fitted for the aligner in the soft- and near-contact mode and steppers.

In making sensors require multiple processing by using different masks to accomplish, it needs reload and multiple aligning for a wafer in order to make a functional wafer, thus, the consuming for making mask are wasted, and used lamps toxic. In the study, a ULVLED stepper with Programmable LCoS or DLP as mask for multiple process wafer is proposed. By a programmable ultraviolet light-emitting diode (UVLED) array with a collimated lens as a transfer lens forms uniform source, to expose programmable LCoS or DLP as mask by using a 1 to 1 lithographic lens. Sensors and optical binary lens are easily made.

The design of four mirrors anti-astigmatism astronomical telescope is carried out for low earth orbit satellite. By integrating with Cassagrain and Schwartzschild eyepieces configurations, the telescope has been designed and fabricated. It contains four mirrors with conic surface, to form an astigmatism aberration free telescope. The system contains two parts: first part is the Cassagrain type telescope for pick up the ground object to form image in the stop position, and the second part is Schwartzschild configurations as relay optics, which is to relay the image of stop to high resolution CCD sensor to provide 0.5 GSD(ground space distance) image within the low orbit as 500 km above sea level. The mechanical system is cylindrical symmetric with optics aberration free and the size is less than a one meter cubic fitted for small satellite. Assembling four with UV, Visible, Near IR and Far IR them in 2X2 stack clustering is fitted for broad bands observation.

A light field display for near eye viewing to reduce the human eye vergence-accommodation conflict (VAC) existing in most stereoscopic VR devices is designed and demonstrated . The 3D perception of the resulting light field is verified by using eye models. The Light Field Displays for Near Eye has verified by focal adjustable camera, and proved its function for free of VAC.

UVLED array aligner for proximity and soft contact exposure has been designed and fabricated. The source is designed for a lithography aligner, each UVLED is arranged in a plate with equal space to form UVLED array source. With AAAAS illumination optics, the aligner is built and has provided the uniformly source. 12 inches wafer with 0.6 micron mask for TSV process has proved in soft contact and proximity exposure modes, with less 1 microns for soft contact. 20 microns for 100 microns proximity exposure, with deviation of 1 micron.

We developed a modified photonic Doppler velocimetry (PDV) configuration which possesses the ability to record wide-range velocity information to evaluate composite material fracture behavior. With the laminate and tunnel design of a fragment generator, the controllable parameters such as fragment size and applied voltage can provide the flexibility for dynamic evaluation under different momentum conditions. We obtained velocity profiles using continuous wavelet transforms and by using our proposed velocity line tracing algorithm. Simulated heterodyne signals and surface morphology of fractures were examined to verify the heterodyne signals. We observed that the obtained tunnel-end velocity of the fragment generator was proportional to the applied voltage.

The design of four mirrors anti-astigmatism astronomical telescope is carried out for low earth orbit satellite. By integrating with Cassagrain and Schwartzschild configurations, the telescope is design. It contains four mirrors with conic surface, to form an aberration free. The system contains two parts: first part is the Cassagrain type telescope for pick up the ground object to the stop position, and the second part is Schwartzschild configurations as relay optics, which is to relay the image to high resolution CCD sensor to provide 0.5 ground space distance image. The system is symmetric with aberration free within a one cubic size fitted for small satellite. The optic mechanical is simple easy to assemble for optical calibration, while the body is rigid in space.

To achieve the smallest line width of IC requires the spherical and coma aberration free lithography optics. Once the aberration of lens is formed, it is hard to amend the mask to original requirement, unless the light pattern figure is adjustable. A programmable UVLED array with a collimated lens as Fourier transfer lens forms an adjustable pattern as the intensity profile to amend the aberration of mask to form aberration free mask intensity pattern into wafer. A 25 X 25 UVLED array with collimated lens is applied to correct the aberration contained mask, is to form a corrected pattern under the requirement for reducing aberration mask to form a smallest line width.

A 1:1 lithography projection has been designed and is fabricated for a 3D integrated circuit fabrication platform. Using a dual triplet as an initial type to form a one-to-one lens and applying a tele-centric structure, the optical common components of an optical system have been designed. The tolerance of the mechanical mounts is simulated by tilting the mounts to single and two aspheric surfaces of lens to show the degradation in the modulation transfer function; thus, the single aspheric-tilted mount in a system is suggested to reach the precision. Furthermore, Koehler illumination is used. By applying partial coherence analysis, the optimized relative numerical aperture was found. As the system is built, optimized performance should be expected.

Due to the lithography demanding high performance in projection of semiconductor mask to wafer, the lens has to be almost free in spherical and coma aberration, thus, in situ optical testing for diagnosis of lens performance has to be established to verify the performance and to provide the suggesting for further improvement of the lens, before the lens has been build and integrated with light source. The measurement of modulation transfer function of critical dimension (CD) is main performance parameter to evaluate the line width of semiconductor platform fabricating ability for the smallest line width of producing tiny integrated circuits. Although the modulation transfer function (MTF) has been popularly used to evaluation the optical system, but in lithography, the contrast of each line-pair is in one dimension or two dimensions, analytically, while the lens stand along in the test bench integrated with the light source coherent or near coherent for the small dimension near the optical diffraction limit, the MTF is not only contributed by the lens, also by illumination of platform. In the study, the partial coherence modulation transfer function (PCMTF) for testing a lithography lens is suggested by measuring MTF in the high spatial frequency of in situ lithography lens, blended with the illumination of partial and in coherent light source. PCMTF can be one of measurement to evaluate the imperfect lens of lithography lens for further improvement in lens performance.

Smartphone require limit space for image system, current lens, used in smartphones are refractive type, the effective focal length is limited the thickness of phone physical size. Other, such as optro-electronics sensing chips, proximity optical sensors, and UV indexer chips are integrated into smart phone with limit space. Due to the requirement of multiple lens in smartphone, proximity optical sensors, UV indexer and other optro-electronics sensing chips in a limited space of CPU board in future smart phone, optro-electronics 3D IC’s integrated with optical lens or components may be a key technology for 3 C products. A design for reflective lens is fitted to CMOS, proximity optical sensors, UV indexer and other optro-electronics sensing chips based on 3-D IC. The reflective lens can be threes times of effective focal lens, and be able to resolve small object. The system will be assembled and integrated in one 3-D IC more easily.

High efficiency coupling of the array of UV light diode light source could be able to replace the traditional mercury light source, while mercury light source requires a large amount of electricity, condenser optics and volume, with hazard environmental issue. It is an urgent need for further requirement of light source for lithography. Although array UVLED could be a replacement of light sources of lithography, there are some existent optical parameters that not fit for optical coupling, such as large divergent cone angle of single chip and half divergent angle of array, which are weak the possibility of application in lithography. Before the broadly accepted by lithography, those shortages have to be overcome. Some techniques, such as designing small divergent cone angle of single chip, or eliminating divergent angle have suggested by fly eye and other methods, yet all of those methods, only improve the coupling efficiency and uniformity of emitted surface in some limited extent. The project is to develop a high coupling efficiency of the optical system used in the array of UV light diodes, which can make the high coupling efficiency, despite UVLED has a small size and large divergent angle. The optical design of illumination has carried out for array UVLED, an illumination optics has designed based on Koehler type illumination, and it has shown reducing the divergent angle to increase in coupling efficiency between the Array UVLED to the mask of lithography. The uniformity of average power has shown excellently fitted for high quality lithography in direct exposure or lens exposure.

The critical dimension(CD) is main factor to determine the line width of semiconductor equipment fabricating ability for the smallest line width of produced electronic components. Modulation transfer function(MTF) has been popularly used to evaluation the optical system, due to the contrast of each line-pair in dimension analytically, however, while the light source is coherent or near coherent for the small dimension near the optical diffraction limit, the MTF is hard to achieve consistently. The study of ultra-violet partial coherence modulation transfer function is to calculate the 1-D and 2-D the line with anoptical design program, to estimate the MTF near the size of diffraction limit. It provides fabricating parameter for a 1-to-1 TSV lithographic system. By applying partial coherence analysis, the optimized relative numerical aperture (RNA) has found. As the system is built, the optimized performance should be expected.

The design and fabrication of common optical components lithography Lens has been carried out for a 1 to 1 stepper. The specification of lens is fulfilled the 3-D lithography system as 2 micron in resolution for 1 inch x 2.8 inches system. The lens has been sophistically designed by dual path in a triplet to reduce the number of components. A single aspherical surface has been applied to reduce the aberration to diffraction limit in lens. The well-made shapes of lens have been suggested. Then, the fabrication of lens has been in the process. Finally, the optical axis of tolerance optical mechanical mountings for lens system in assembly has been analyzed, and valuable for assembly and fabrication.

In the past decade, the display format from (HD，High Definition) through Full HD(1920X1080)，to UHD(4kX2k), mainly guides display industry to two directions: one is liquid crystal display(LCD) from 10 inch to 100 inch and more, and the other is projector. Although LCD has been popularly used in market; however, the investment for production such kind displays cost more money expenditure, and less consideration of environmental pollution and protection[1]. The Projection system may be considered, due to more viewing access, flexible in location, energy saving and environmental protection issues. The topic is to design and fabricate a short throw factor liquid crystal on silicon (LCoS) projection system for cinema. It provides a projection lens system, including a tele-centric lens fitted for emitted LCoS to collimate light to enlarge the field angle. Then, the optical path is guided by a symmetric lens. Light of LCoS may pass through the lens, hit on and reflect through an aspherical mirror, to form a less distortion image on blank wall or screen for home cinema. The throw ratio is less than 0.33.

An ultrashort throw liquid crystal on silicon (LCoS) projector for home cinema, virtual reality, and automobile heads-up display has been designed and fabricated. To achieve the best performance and highest-quality image, this study aimed to design wide-angle projection optics and optimize the illumination for LCoS. Based on the telecentric lens projection system and optimized Koehler illumination, the optical parameters were calculated. The projector’s optical system consisted of a conic aspheric mirror and image optics using either symmetric double Gauss or a large-angle eyepiece to achieve a full projection angle larger than 155 deg. By applying Koehler illumination, image resolution was enhanced and the modulation transfer function of the image in high spatial frequency was increased to form a high-quality illuminated image. The partial coherence analysis verified that the design was capable of 2.5 lps/mm within a 2 m×1.5 m projected image. The throw ratio was less than 0.25 in HD format.

We discovered that the transmission spectra of bending long period fiber gratings (LPGs) exhibit a splitting of loss peaks. This phenomenon allows LPGs can be used as the strain sensors and the accelerometer.