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Precision optical systems, such as lithographic projection lens or cameras for satellites, typically composed of glass or ceramics optical components. In the manufacturing processes of glass and ceramics components, grinding is a key technique for curvature generation (CG) of optical surface. However, dimension errors and sub-surface damage (SSD) of components occur during the CG process. High material removal rates during the CG leads to deeper SSD on optical surface. The SSD must be removed by subsequent lapping and polishing processes to ensure high optical surface quality. However, these processes are complex, and a precise process to remove SSD from the aspheric surfaces with tens or hundreds of microns of departure from best fit sphere (BFS) is required. Thus, an efficient precision lens fabrication method can reduce the depth of SSD and help to control the dimension error during the CG process. We developed a five-axis grinding system with intelligent machining techniques to improve the quality of CG process. The intelligent grinding system based on the Tongtai five-axis machine (GT-630) was combined with two measurement modules of the Renishaw measurement probe. A customized computer-aided manufacturing software was developed and applied to this grinding system. Spherical and aspherical components with a maximum diameter of 600 mm can be fabricated using the grinding system. To improve the grinding efficiency, an ultrasonic-assisted module was combined with the BBT 40 tool arbor. The frequency range, amplitude, and power of the ultrasonic device were 15–40 kHz, 0.2–2 μm, and 1000 W, respectively. The intelligent grinding system included several vibration, temperature, and acoustic emission sensors and a microphone to monitor the dynamic status of machine during the grinding process and help to quality control. The wear of the diamond grinding wheel could be predicted immediately by analyzing the collected data in this system. A five-axis machine was applied to an intelligent grinding system for large glass lenses. The fabrication time of 200 mm diameter aspheric lenses reduced about 3 weeks by using this intelligent grinding system to integrate aspherization processes into curvature generation to become an aspheric curvature generation step.

This research increases the ability and value of a traditional vertical lathe and applies to manufacture a precise lens cell for the optical industry. The optical performance is limited by the residual centration error and position accuracy of conventional assembly methods. Recently, the development of a poker-chip assembly system with high-precision lens barrels has overcome these limitations and provided a solution for ultra-high-performance optical systems. To develop a high-precision lens cell by using poker-chip assembly, an alignment turning system (ATS), is developed based on a vertical lathe and equipped with tactile and optical measurement modules. Inside the ATS, the building-in the vibration/temperature monitoring sensors, which help to self-monitoring and network communication with the intelligent manufacturing techniques, to understand and master the reliability and efficiency of ATS. This system can manufacture precise lens cells, applied for optical metrology, high numerical aperture objective lenses, and lithography projection lenses. This paper describes the design and development of the ATS and its capabilities. The ATS is composed of measurement, alignment, and turning modules. After the ATS completes the measurement, alignment, and turning processes, the centration error of a lens cell, which is 200 mm in diameter, can be controlled to within 10 arcsec. Here, a lens cell with three subcells was assembled through the poker-chip method; each subcell was measured and then it underwent alignment and turning processes. The lens assembly test was performed five times by three technicians, and the average transmission centration error of the assembly lens was 12.45 arcsec. The results demonstrate that the ATS can achieve considerable assembly efficiency for high-precision optical systems.

A thermal deformation monitoring system was developed in this study by applying the thermocouple sensors and capacitive displacement sensors, along with a Long Short Term Memory (LSTM) Network Model classifier, for the alignment turning system (ATS). An ATS can simultaneously provide the functions of measuring the centration error and dimensions of the lens cell in-line, and machining the lens barrel housing with reference to the lens optical axis. The ATS can manufacture precise lens cells, applied for optical metrology, high numerical aperture objective lenses, and lithography projection lenses. While rising temperature, the thermal error would occur on hydrostatic spindle which build in ATS. Therefore, the predetermined machining point would offset, thereby resulting in the machining error. In order to acquire the oil temperature of rotor and the relative thermal displacement between hydrostatic spindle and turret, the thermocouple sensors and capacitive displacement sensors were assembling on ATS. According to the measurement of oil temperature and relative displacement, the thermal deformation monitoring system of ATS hydrostatic spindle was established. Cause of the high resolution of capacitive displacement sensors, the more precise measurement values could be obtain so that the monitoring system would have higher accuracy. LSTM is a variant of Recurrent Neural Network (RNN) and could remember longer information changes than traditional RNN. The thermal deformation monitoring system with LSTM could be applied to compensate the thermal error to improve the workpiece quality in real-time, and also could save time and money of warming up centering machines in the future. Results shows that the mean square error (MSE) and RScore of forecasting thermal error is less than 0.0002 and higher than 0.997, which is highly accurate forecasting.

Recently, freeform surfaces have been widely used in various optical systems because of their high flexibility and ability to correct aberrations when off-axis optical components are considered. Among freeform optics there are the head-up displays (HUDs) for vehicles, HUDs are increasingly used in new vehicles as they keep the driver’s head up and eyes focused on the road for the sake of improved safety. Fora compact size in the limited space of the vehicle, an HUD is typically an off-axis mirror system (including the windshield). The freeform mirror is not only employed to correct the off-axis aberrations caused by the windshield but also is used to provide an optical power for system magnification. This paper focuses on the design, fabrication, and measurement of a freeform mirror developed for a vehicle HUD system. We herewith report the design of the freeform surface including extended its polynomials description and its optimization. Using an ultra-high precision manufacturing and metrology strategy that is based on the use of a multi-axis machining center and advanced nano-metric profiler, the form error of the freeform mirror was precisely controlled according to system requirement. The fabricating method was realized on a machine equipped with a servo tool servo (STS) a and the combination of CXZ coordinates was programmed,. Finally, the freeform surface is fabricated and measured experimentally by ultrahigh accurate 3D profilometer.

Indoor positioning systems (IPSs) provide physical location information of indoor targets (i.e., people or devices). Traditional optical lens manufacturing companies must enable the operator and customers to grasp the progress of optical lens production, a goal that the global manufacturing industry has been now pursuing. This study incorporates an IPS design into the manufacturing and processing procedures of optical lenses and uses an indoor positioning algorithm to calculate location-based information to achieve effective indoor positioning. Therefore, in this paper, this study proposes that using Bluetooth low energy sensors to perform signal strength fingerprinting identification can increase the accuracy of positioning. The results reveal that the proposed method can attain a certain level of accuracy in indoor positioning, and integrated into the optical lens production management systems, to achieve optical lens smart manufacturing.

The spectrophotometer is one of the instruments designed and manufactured by the advanced opto-mechanical technologies. To maintain its accuracy and preciseness, the instruments are required to be calibrated frequently. The transmittance measurement uncertainty of a spectrophotometer with considerations of the normal incidence of light beam and operator manipulation factors is performed. The calibration data and regular measured data can be transferred to the servo data center via internet for further data analysis, instrument healthy examination and predicted maintenance period. A double beam spectrophotometer is utilized, taking advantage of the direct comparison of the luminous intensity to evaluate the uncertainty. To measure the transmittance of a sample with a few tenths percent in calibration, the sample is required to be smooth surface, uniform and homogeneous composition, and environmental stability. The measured transmitted beam should be focused inside and no light will be scattered outside of the collecting integrating sphere. A series of transparent thin films, including absorb Ni film, high index TiO 2 film and low index SiO 2 film alternatively deposited carefully on the fused quartz substrates, are the calibration samples. Equations are given to calculate the transmittance for beam being normally incident on the substrate. Factors such as material aging and non-uniform optical thickness can introduce systematic errors into the calibration, and the errors must be minimized by proper choice of materials and preparation techniques. The environmental range of the temperature and the relative humidity during the measuring process are controlled as 23±1.5 °C and 50%±10% respectively. The calibrated transmittance ranges are within 10%–100%. The optimal expanded combination uncertainties of the system are found to be 0.23247 (T1-1: above T30 %), 0.13265 (T1-2:T30%∼8%), 0.04728 (T1-3:T8%∼0.92%) and 0.02910 (T1-4:T0.92%∼0.107%) in the wavelength ranges of 400 nm–700 nm.

We present a portable non-contact displacement sensor (NCDS) based on astigmatic method for micron displacement measurement. The NCDS are composed of a collimated laser, a polarized beam splitter, a 1/4 wave plate, an aspheric objective lens, an astigmatic lens and a four-quadrant photodiode. A visible laser source is adopted for easier alignment and usage. The dimension of the sensor is limited to 115 mm x 36 mm x 56 mm, and a control box is used for dealing with signal and power control between the sensor and computer. The NCDS performs micron-accuracy with ±30 μm working range and the working distance is constrained in few millimeters. We also demonstrate the application of the NCDS for lens centration error measurement, which is similar to the total indicator runout (TIR) or edge thickness difference (ETD) of a lens measurement using contact dial indicator. This application has advantage for measuring lens made in soft materials that would be starched by using contact dial indicator.

The poker chip assembly with high precision lens barrels is widely applied to ultra-high performance optical system. ITRC applies the poker chip assembly technology to the high numerical aperture objective lenses and lithography projection lenses because of its high efficiency assembly process. In order to achieve high precision lens cell for poker chip assembly, an alignment turning system (ATS) is developed. The ATS includes measurement, alignment and turning modules. The measurement module is equipped with a non-contact displacement sensor (NCDS) and an autocollimator (ACM). The NCDS and ACM are used to measure centration errors of the top and the bottom surface of a lens respectively; then the amount of adjustment of displacement and tilt with respect to the rotational axis of the turning machine for the alignment module can be determined. After measurement, alignment and turning processes on the ATS, the centration error of a lens cell with 200 mm in diameter can be controlled within 10 arcsec. Furthermore, a poker chip assembly lens cell with three sub-cells is demonstrated, each sub-cells are measured and accomplished with alignment and turning processes. The lens assembly test for five times by each three technicians; the average transmission centration error of assembly lens is 12.45 arcsec. The results show that ATS can achieve high assembly efficiency for precision optical systems.

In general, the drop-in and cell-mounted assembly are used for standard and high performance optical system respectively. The optical performance is limited by the residual centration error and position accuracy of the conventional assembly. Recently, the poker chip assembly with high precision lens barrels that can overcome the limitation of conventional assembly is widely applied to ultra-high performance optical system. ITRC also develops the poker chip assembly solution for high numerical aperture objective lenses and lithography projection lenses. In order to achieve high precision lens cell for poker chip assembly, an alignment turning system (ATS) is developed. The ATS includes measurement, alignment and turning modules. The measurement module including a non-contact displacement sensor and an autocollimator can measure centration errors of the top and the bottom surface of a lens respectively. The alignment module comprising tilt and translation stages can align the optical axis of the lens to the rotating axis of the vertical lathe. The key specifications of the ATS are maximum lens diameter, 400mm, and radial and axial runout of the rotary table < 2 μm. The cutting performances of the ATS are surface roughness Ra < 1 μm, flatness < 2 μm, and parallelism < 5 μm. After measurement, alignment and turning processes on our ATS, the centration error of a lens cell with 200mm in diameter can be controlled in 10 arcsec. This paper also presents the thermal expansion of the hydrostatic rotating table. A poker chip assembly lens cell with three sub-cells is accomplished with average transmission centration error in 12.45 arcsec by fresh technicians. The results show that ATS can achieve high assembly efficiency for precision optical systems.

Collimator design is essential for meeting the requirements of high-precision telescopes. The collimator diameter should be larger than that of the target for alignment. Special supporting structures are required to reduce the gravitational deformation and control the surface deformation induced by the mounting force when inspecting large-aperture primary mirrors (M1). A ZERODURÂŽ mirror 620 mm in diameter for a collimator was analyzed using the finite element method to obtain the deformation induced by the supporting structures and adjustment mechanism. Zernike polynomials were also adopted to fit the optical surface and separate corresponding aberrations. The computed and measured wavefront aberration configurations for the collimator M1 were obtained complementally. The wavefront aberrations were adjusted using fine adjustment screws using 3D optical path differences map of the mirror surface. Through studies using different boundary conditions and inner ring support positions, it is concluded that the optical performance was excellent under a strong enough supporter. The best adjustment position was attained and applied to the actual collimator M1 to prove the correctness of the simulation results.

Optical interference coatings designed for use in a space-grade multispectral assembly in a complementary metal-oxide‐semiconductor sensor were deposited on glass by ion-beam-assisted deposition for a Cassegrain-type space-based remote-sensing platform. The patterned multispectral assembly containing blue, green, red, near infrared, and panchromatic multilayer high/low alternated dielectric band-pass filter arrays in a single chip was fabricated by a mechanical mask and the photolithography process. The corresponding properties of the films were investigated by in situ optical monitoring and spectrometry. It was found that the optical properties were significantly improved by employing ion-beam-assisted deposition. The average transmittances were above 88% for the multispectral assembly, with a rejection transmittance of less than 1% in the spectral range 350–1100 nm. To estimate the optical stability of optical coatings for aerospace applications, a space environment assuming a satellite orbiting the Earth at an altitude of near 800 km was simulated by a Co60 gamma (γ) radiation test.

Direct imaging has widely applied in lithography for a long time because of its simplicity and easy-maintenance. Although this method has limitation of lithography resolution, it is still adopted in industries. Uniformity of UV irradiance for a designed area is an important requirement. While mercury lamps were used as the light source in the early stage, LEDs have drawn a lot of attention for consideration from several aspects. Although LED has better and better performance, arrays of LEDs are required to obtain desired irradiance because of limitation of brightness for a single LED. Several effects are considered that affect the uniformity of UV irradiance such as alignment of optics, temperature of each LED, performance of each LED due to production uniformity, and pointing of LED module. Effects of these factors are considered to study the uniformity of LED Light Illumination. Numerical analysis is performed by assuming a serious of control factors to have a better understanding of each factor.

A precision angle measurement system, also called autocollimator, is a precise module at optical testing or fabricating system. A precision angle measurement system can be measured straightness of guideway, accuracy of rotating platform, parallel and decentered of optical components. Instrument Technology Research Center (ITRC), National Applied Research Laboratories (NARLabs) develops precise opto-mechanical engineering over 35 years, and has many experiences for the development of opto-mechanical system. In recent years, ITRC develops high precise optical components and modules using in semiconductor equipment. In order to upgrade self-made abilities of high precision angle measurement system in Taiwan, ITRC develops a precision angle measurement system with 300 mm in focal length, 46 mm in diameter, and 6.5 in f/# in this paper.

This paper introduces the development of a double-sided micro lens array (DSMLA) for application in micro laser projectors. For commercial mass production, it is necessary to investigate the concurrent engineering of optical design, mold fabrication, and plastic injection molding at once. This experiment based the design of the micro lens array on the scalar diffraction theory. The proposed DSMLA can simultaneously shape red, green, and blue laser beams into a uniform projection pattern. An ultra precision diamond turning machine using a slow tool servo method fabricated the mold. The study considered optical design constraints from the feedback of mold fabrication and plastic injection molding, measuring and comparing fabricated samples with calculated results. Experimental results show that the fabricated DSMLAs achieve the desired function and application feasibility for micro laser projectors.

A RGB lasers illuminated three-panel LCoS projector has been developed to demonstrate the viability of a double-side microlens array as a diffractive beam shaper. By oscillating the beam shaper, both the uniformity and speckle pattern were significantly improved. The contrast ratio of the image speckle was measured to be below 8%.

Focal plane assembly (FPA) is an important component for modern remote sensing instruments. Array or linear CCD/CMOS detectors are usually applied. Linear detectors are often used in the space project to have a wider swath. In a remote-sensing project, five spectral ranges are desired. The spectral ranges are designated to be one panchromatic (PAN) band from 450 to 700 nm and four multispectral (MS) bands from 455 to 900 nm. Pixel size of the PAN band is 10 μm, and those for MS are 20 μm. Pixel numbers are 12,000 and 6,000 for PAN and MS bands, respectively. The FPA is consisted of a filter with five stripe band-pass thin films, filter mask and a five-line detector. The arrangement of the detector is B1, B2, Pan, B3 and B4 from the top to the bottom. In order to give the alignment tolerance, an analysis of the parameters of each component in FPA has been performed. Ray tracing method has been applied to have an image projection onto the plane where thin films are located. Spread sheet computation was adopted to simulate the situations when the alignment parameters were changed. According to the analysis, some supplement wideness to the stripe thin films has to be added to have a satisfied alignment tolerance.

In this study, the Plücker coordinates representation is used to formulate the ruled surface and the molecular path for pumping speed performance evaluation of a molecular vacuum pump. The ruled surface represented by the Pliicker coordinates is used to develop a criterion for when gas molecules hit the pump surface wall. The criterion is applied to analyze the flow rate of a new developed vacuum pump in transition regimes by using the DSMC (Direct Simulation Monte Carlo) method. When a molecule flies in a neutral electrical field its path is a straight line. If the molecular path and the generators of a ruled surface are both represented by the Pliicker coordinates, the position of the molecular hit on the wall can be verified by the reciprocal condition of the lines. The Plücker coordinates representation is quite convenient in the DSMC method for this three-dimensional molecular flow simulation.

This article shows a spiral-grooved turbobooster pump, which has a momentum transfer-type vacuum pump function, and is capable of operation in a discharge pressure range up to 1000 Pa. Transitional flow pumping speeds are improved by a well-designed midsection element. Pumping performance of this new pump is predicted and examined by both of the computational fluid dynamics method and the direct simulation Monte Carlo method. These two complementary approaches are successfully being used to investigate the whole pumping speed curve from the viscous high-pressure to the molecular low-pressure range. Also, the developed pump is tested on an evaluation system constructed according to JVIS-005 standard. Good agreement between analytical results and experimental data are shown. Furthermore, to achieve a clean, safe, and reliable pumping process, this pump is designed with and operated by an innovative digital magnetic-bearing system.

Cassegrain optical systems are widely used in remote sensing instrument. Cassegrain telescope is composed of a primary mirror (M1), a secondary mirror (M2), and a set of correction lenses. The system aberrations of telescope could be corrected and balanced by M1 and M2. In the event of deformation of telescope assembly, the non-symmetry aberrations will be induced to the optical system and reduce the optical performance. The non-symmetry aberrations can be measured after completing M1 and M2 assembly and alignment processes. Compensating this identified error to M1 or M2 can improve the optical performance of the telescope system. The error compensation on M2 is more efficient due to its smaller aperture and quickly assembly and de-assembly processes. In this study, we map the system wavefront error caused by deformation of mirror supporting and gravity onto the designed aspheric surface of M2. The surface of M2 becomes a freeform from aspheric. The polishing process combines the techniques of conventional lapping and CNC polishing. We apply the conventional spherical lapping process to quick remove the sub-surface damage (SSD) layer and to get the accurate radius of best fit sphere of the designed aspheric surface with fine surface texture simultaneously. The polishing and metrology processes were performed by using Zeeko IRP1000 polisher and QED ASI. A Φ 150 mm mirror with freeform surface was completed.

Dry vacuum pump is a core device in semiconductor and electro-optic industries for vacuum purpose. The pumping characteristics of dry vacuum pump could affect significantly the performance of secondary pump. This article present a method which integrates a mobile device through the remote application program to measure the vacuum pressure, sound, vibration, and power for a dry vacuum pump system. Moreover, the LabVIEW was implemented to the system for pumping experiment control. The pumping characteristics monitored by mobile device can be useful for processing monitor.

A new design is the concept of using digital camera embedded with magnifier lens and LEDs adapter as a portable digital microscope inspecting instrument to recorder tiny target under quality assurance on production line. The apparatus is demonstrated and presented the difference between the other portable digital microscope.

In this paper, a fast auto-focus microscope system was developed based on the astigmatic method. A collimated infrared laser beam was employed in the infinite-corrected microscope optical axis by the beam splitter and reflected by the sample surface. By embedding an astigmatic lens in the system, the reflected laser beam has different focal lengths in the sagittal and tangential planes. As the microscope's relative distance varies, the reflected laser beam shape also varies and can be detected by an embedded four-quadrant photodiode, i.e., the focus error signal (FES) can be found. Then, a fast auto-focus system can be realized by converting the FES to the microscope's defocus distance. We designed an astigmatic auto-focus system for a 20× objective lens with a ±50 µm working range, and this system could also be used for 10× and 5× objectives with ±200 µm and ±800 µm working ranges, respectively.

This article successfully presented the concept of digital camera changing digital microscope using additional adapter with one lens, light emitting diodes, single AAA battery cell, and simple construction without interfering digital camera function. It will be very friendly using general instrument to record miniature target image data in scientific and engineering fields in the future.