Plastic Lenses Research Articles

Boronic acid fluorescent sensors for monosaccharide signaling based on the 6-methoxyquinolinium heterocyclic nucleus: progress toward noninvasive and continuous glucose monitoring

The synthesis, characterization, and spectral properties of strategically designed boronic acid containing fluorescent sensors, o-, m-, p-BMOQBA, for the potential detection of tear glucose concentrations when immobilized in plastic disposable contact lenses is described. The new probes, BMOQBAs, consist of the 6-methoxyquinolinium nucleus as a fluorescent indicator, and the boronic acid moiety as a glucose chelating group. A control compound BMOQ, which has no boronic acid group and therefore does not bind monosaccharides has also been prepared. In this paper, we show that structural design considerations of the new probes have afforded for their compatibility within the lenses, with reduced probe sugar-bound p K a favorable with the mildly acidic lens environment. In addition, the new probes are readily water soluble, have high quantum yields, and can be prepared by a simple one-step synthetic procedure.

Vertical cavity surface emitting laser focusing using a miniature precision molded plastic lens

We report the design of a vertical cavity surface emitting laser (VCSEL) focusing module, suitable for barcode scanning applications. The dimensions of the plastic lens housing are precisely controlled to set the distance between the laser and the focusing lens, without the need of alignment. Measurement results of prototype devices are also reported.

Lens Design of Compatible Objective Lens for Blu-ray Disc and Digital Versatile Disk with Diffractive Optical Element and Phase Steps

A two-element objective lens which is compatible with for digital versatile disk (DVD) and Blu-ray Disc (BD) and has adequate optical performances in terms of off-axis wavefront and on-axis chromatic aberration for both optical heads has been designed. The first-order diffracted light is used for DVD and the second-order one is used for BD. We analyzed chromatic spherical aberration and found that using first- and second-diffracted lights causes 20 mλ/nm chromatic spherical aberration at a wavelength of 400 nm. However, using 5λ and 10λ phase steps can reduce chromatic spherical aberration to 7 mλ/nm. The designed two-element lens consists of the first plastic lens, on which there is diffractive optical element, and the second plano-convex glass molded lens.

The quasi-optical analysis of Bessel beams in the far infrared

We discuss the Gaussian beam mode analysis of Bessel beams, eigen-solutions of the wave-equation in cylindrical polar coordinates which neither change form nor spread out as they propagate. Approximate, limited diffraction finite aperture, pseudo-Bessel beams having intense on-axis spots with large depths of field can be produced experimentally in the far infrared by using plastic conical lenses, known as axicons. We illustrate the physical insight provided by Gaussian beam mode analysis of such systems. Such pseudo-Bessel beams can be usefully approximated by high-order Gaussian–Laguerre modes, which have similar propagation characteristics. The size of the on-axis spot produced by an axicon, and its depth of focus, can be estimated from a single best-fit high-order Gaussian–Laguerre mode, and a more detailed description of behaviour can be achieved by adding a few additional modes of neighbouring orders. The strength of Gaussian beam mode analysis is that it is straightforward to model the propagation of Bessel beams through complex systems of long wavelength optical components, such as apertures, mirrors, and lenses. We report the experimental generation and measurement of a 0.1 THz Bessel beam, and show that useful performance is possible for an axicon having a scale size just one order of magnitude greater than the wavelength. This work confirms the technical feasibility of designing and building long-wavelength optical systems based on Bessel beams.

Elimination of the Circumferential Part of a Plastic Rod Lens for Improving its Optical Resolution

A commercially available plastic rod-lens array has an optical resolution applicable to 200 dots per inch (dpi) devices. Recently, we developed a technique for dyeing the circumferential part of the rod lens, which achieved a sufficient resolution for 300 dpi devices but not for 400 dpi devices. In this study, we have developed a technique of eliminating the circumferential part of the rod lens for improving its optical resolution. Both higher resolution applicable to 400 dpi devices and high durability have been realized by this surface eliminating technique.

Improvement of chromatic aberration of a plastic rod lens array. 1. Combination-color lens arrays consisting of several kinds of rod lenses with different gradient constants and different color filter functions.

We propose a new type of rod lens array with improved chromatic aberration. The new rod lens array consists of several kinds of rod lenses with different gradient constants and different color filter functions. The gradient constant of each lens was prepared such that the total conjugate length was identical to the specific wavelength of the lens with a constant lens length. We call our new type of rod lens array a combination-color lens array. The characteristics of this color-type lens array are as follows: high angular aperture, short focal length, and ease of production with established procedures. The optical resolution of the rod lens array is 300 dpi in a wide wavelength range that is high enough to be applied to color scanners.

Optimization design of the split doublet using the shape factors of the third-order aberrations for a thick lens

An improved optimization method is presented for doublet design using the shape factor of the third-order aberrations of a thick lens to compensate high-order aberrations. This method can effectively evaluate a minimal area of aberration curves bounded by the ray-fan diagram. For the proposed optimization program, taking the RMS value of the spot diagram to be less than the diffraction limited value of the point spread function (PSF) as the evaluated criterion is suggested. The design specifications for the optimized doublet are F/3.333 and semi-field angle of 1°, within the visible spectral range. Two design examples of the doublet, one a glass lens and the other a plastic lens, are presented. The results show well-designed doublets when compared with Kingslake's design.

Optimization design of the split doublet using the shape factors of the third-order aberrations for a thick lens

Abstract An improved optimization method is presented for doublet design using the shape factor of the third-order aberrations of a thick lens to compensate high-order aberrations. This method can effectively evaluate a minimal area of aberration curves bounded by the ray-fan diagram. For the proposed optimization program, taking the RMS value of the spot diagram to be less than the diffraction limited value of the point spread function (PSF) as the evaluated criterion is suggested. The design specifications for the optimized doublet are F/3.333 and semi-field angle of 1°, within the visible spectral range. Two design examples of the doublet, one a glass lens and the other a plastic lens, are presented. The results show well-designed doublets when compared with Kingslake's design.

Focused Ion Beam Machining of Precision Die for Micro Optical Lens Molding

Glass-like carbons (GCs) for press molding die of micro optical glass lens and electroless Ni-P alloy films for injection molding die of micro optical plastic lens were machined by focused ion beam (FIB) and their dimensional accuracy, surface roughness and transcriptional performance were investigated. The GCs completed a fine surface roughness of Ra=1nm after FIB machining, although their FIB etching rate was decreased to a half rate of Si(100) single crystal. On the other hand, amorphous Ni-P alloy films containing phosphorus more than 7wt% possessed higher etching rate than Si(100) crystal, as well as fine surface roughness less than 8nm. Precision GCs and Ni-P alloy films molding dies with 3-D microlens array of 7μm square were fabricated by FIB. Subsequently, transcriptional performance to micro optical lens was evaluated on precision GC dies.

Dyeing of the Circumferential Part of a Plastic Rod Lens for Improving its Optical Resolution

A plastic rod-lens array that we developed industrially with a continuous spinning technique has an optical resolution of 200 dpi (4 lp/mm), and it has been used for facsimile machines and other applications. However, this resolution is still insufficient for its application in image scanners, copy machines, and light emitting diode (LED) printers. During the study for improving the optical resolution of the plastic rod-lens array, we have confirmed that this resolution is determined by the deviation of refractive index distribution from the ideal one at the outer circumferential part. Therefore, we have developed a technique for dyeing the outer circumferential part of the rod lens in order to achieve the higher optical resolution power of 300 dpi (6 lp/mm).

System for the design, manufacture, and testing of custom lenses with known amounts of high-order aberrations.

Now that excimer laser systems can be programmed to correct complex aberrations of the eye on the basis of wave-front measurements, a method is needed to test the accuracy of the system from measurement through treatment. A closed-loop test method was developed to ensure that treatment plans generated by a wavefront measuring system were accurately transferred to and executed by the excimer laser. A surface was analytically defined, and a Shack-Hartmann-based wave-front system was used to formulate a treatment plan, which was downloaded to an excimer laser system. A plastic lens was ablated by the laser and then returned to the wave-front device, where it was measured and compared with the analytically defined wave-front surface. The two surfaces agreed up to 6th-order Zernike terms, validating the accuracy of the system.

Mutual diffusion process for continuous fabrication of graded-index plastic rod lenses.

We propose a new process for fabrication of plastic rod lenses based on the traditional method of fiber extrusion. The process consists of the following steps: multilayer conjugate extrusion, monomer diffusion between adjacent layers, and photopolymerization of an uncured strand fiber. We call this process a mutual diffusion process for continuous plastic rod lens fabrication. Characteristics of this process are as follows: fast production speed (approximately 100 cm/min), precision control of refractive-index distribution, high angular aperture, and long-term reliability. The optical resolution of the rod-lens array is 300 dpi, which is high enough for application to G3 facsimiles with transmission time of less than 1 min and monochromatic scanners.

Light-emitting diode-based indirect fluorescence detection for simultaneous determination of anions and cations in capillary electrophoresis

This report presents simultaneous analysis of cations and anions by capillary electrophoresis (CE) in conjunction with indirect fluorescence detection using a blue light-emitting diode (LED), based on the displacement of fluorescein with anionic EDTA–metal complexes and anions. A new focusing system combined with a plastic lens and a 40× objective was developed and used effectively to focus the diverging beam of the LED on the capillary. The optimum compositions for simultaneous analysis of metal ions and anions are the samples prepared in 5 mM borate, pH 9.2, containing 2 mM EDTA and the background electrolytes (BGEs) consisting of 5 mM borate buffer, 5 μM fluorescein, and 1 μM NaCl at pH 9.2. Using this pre-capillary complexation method, the analysis of a sample containing five metal ions and eight anions was accomplished in 8 min, with the relative standard deviation values for the migration times less than 2.0%. The peak heights against the concentrations of the metal ions and anions are linear in 10–1000 and 50–2000 μM, with correlation coefficients better than 0.998, and 0.982, respectively. The limits of detection at a signal-to-noise ratio 3 of up to 14.6 μM for formate and as low as 3.7 μM for Ni 2+. The results of the analyses of pond water and a Chinese herbal soup present the advantages of this method, including simplicity, rapidity, reproducibility, and low costs.

정밀모형안을 이용한 Head Mounted Display용 렌즈계 설계

본 논문에서는 구면수차와 Stiles-Crowford 효과를 고려하여 인간의 눈을 모델링한 정밀모형안과 등가인 렌즈모듈 모형안의 설계에 관하여 논의하였고, 렌즈모듈 모형안을 적용한 Head Mounted Display(HMD)용 광학계를 설계 및 평가하였다. HMD용 광학계에서 요구되는 소형화, 고성능 및 고해상도 등의 필수조건들을 만족시키기 위해 회절광학소자와 비구면을 이용하여 색수차와 단색수차를 보정하였다. SVGA급 480,000화소를 갖는 0.47 인치 micro-display, 플라스틱 hybrid 렌즈, 그리고 렌즈모듈 모형안으로 HMD용 광학계를 구성하였다. 설계된 광학계의 초점거리는 31.25 mm, FOV는 24H<TEX>$\times$</TEX>18V<TEX>$\times$</TEX>30D degrees, 그리고 전장길이는 59.1 mm이다. 결과적으로, 사용자가 편안함을 느낄 수 있는 HMD에 유용한 광학계를 얻었다. We discussed the design of lens module schematic eyes equivalent to finite model eyes, which are used to model the human eye based on spherical aberration and Stiles-Crowford effect. The optical system for head mounted display (HMD) is designed and evaluated using lens module schematic eyes. In addition to a compact HMD system, an optical system with high Performance is required. To satisfy these requirements, we used diffractive optical elements and aspheric surfaces so that the color and mono-chromatic aberrations were corrected. The optical system for HMD is composed of 0.47 inch micro-display of SVGA grade with 480,000 pixels, a plastic hybrid lens for the virtual image, and the lens module schematic eyes. The designed optical system fulfills the current specifications of HMD: such as, EFL of 31.25 mm, FOV of 24H<TEX>$\times$</TEX>18V<TEX>$\times$</TEX>30D degrees, and overall length of 59.1 mm. As a result, we could design an optical system useful for HMD; the system is expected to be comfortable while the user wears it.

3 차원 입체요소를 사용한 사출성형품의 잔류응력 예측 및 후변형 해석

Most of CAE analyses for injection molding heve been based on the Hele Shaw's approximation: two-dimensional flow analysis. In some cases, that approximation causes significant errors due to loss of the geometrical information as well as simplification of the flow characteristics in the thickness direction. Although injection molding analysis software using three-dimensional solid elements has been developed recently, such as Moldflow Flow3D, it does not contain a deformation analysis function yet. The present work covers three-dimensional deformation analysis of injection molded plastic parts using solid elements. Anumerical scheme for deformation analysis has been proposed from the results of injection molding analysis using Moldflow Flow3D. The accuracy of the proposed approach has been verified through a numerical analysis of rectangular plates with various thicknesses in comparison with the classical shell-based approach. In addition, the reliability of the approach has also been proved through an industrial example, an optical plastic lens, in comparison of real experiments.br/

Plastic lens moves IR thermometer into glass free zone

Plastic lens moves IR thermometer into glass free zone

Scratch and Abrasion Resistant Coatings on Plastic Lenses—State of the Art, Current Developments and Perspectives

The manufacturing of ophthalmic lenses is one of the most important markets worldwide and, therefore, strong research efforts are undertaken to continuously improve the quality of the products, either silicate glasses or organic polymer lenses. Hybrid sol-gel based materials play a major role in this highly competitive field and have contributed significantly to the commercial success of the organic base materials. Recent developments concern fast curing and patternable coatings that might soon become part of this business. The compatibility of hybrid sol-gel materials either with organic dyes or with inorganic vacuum borne coatings offers further possibilities to develop highly sophisticated lenses meeting not only customer needs like perfect corrective function, high optical quality and protection, but also high durability as well as cosmetic and decorative aspects. An overview and a few recent developments are outlined below.

Interferometric measurement of the refractive-index distribution in plastic lenses by use of computed tomography.

A nondestructive measurement method that makes possible the measurement of a three-dimensional refractive-index distribution of any shape plastic lens is presented. In this method, a Mach-Zehnder interferometer and shearing interferometer are combined into a single optical system and are used selectively. Interference fringes of a test object that is immersed in matching liquid are detected at various rotation angles. And transmitted wave fronts are calculated with these interference fringes. Finally, the refractive-index distribution is obtained by computed tomography analysis. In addition, accurate control of the matching liquid temperature makes it possible to measure the absolute refractive index of the test object. This system has good performance with a measurement accuracy of 10(-4) or better peak to valley.

A statistical experimental study of the injection molding of optical lenses

In the injection molding of plastic optical lenses, the processing conditions have critical effects on the quality of the molded lenses. Since there are many process parameters involved in an injection molding process, and more importantly, an optical lens needs precisely controlled surface contours, determination of the processing conditions for lens molding is very complicated. The objective of this work is to investigate experimentally some effects of the molding conditions on the surface contours of injection molded lenses. A spherical lens was molded using polycarbonate. The surface profiles of the lenses molded under different processing conditions were measured using a laser interferometer. The birefringence of the lenses was measured using a specially designed polarimeter to characterize the residual stress in the lenses. Statistical methods were employed in the experimental studies in order to systematically analyze the effects of various process parameters on the lens contour errors. The process parameters studied include injection speed, holding pressure and mold temperature, etc. The contour errors were correlated to the mold shrinkage and the residual stress in the molded lenses. The study shows that in addition to the mold shrinkage the stress also plays a vital role in determining the lens surface contours.

Development of a noncontact optical sensor for measuring the shape of a surface and thickness of transparent objects

This paper deals with the non-contact optical sensor to measure the shape and the thickness of transparent plates such as glass panel of LCD(Liquid Crystal Display). The conventional methods to obtain the shape or thickness of transparent plates are contact type sensor such as LVDT(Linear Variable Differential Transformer). Due to the contact between the tip of the sensor and the surface of objects, the tip is abraded. In addition the casting glass under high temperature results in extendin g the size of sensor body. The accuracy of the sensor is degraded due to these reasons. In this paper, to overcome these problems, we proposed a low cost non-contact optical sensor that is composed of a Hologram laser unit used for optical pickup of CD player and a plastic lens. To evaluate the performance of the proposed optical sensor, a series of experiments ware performed for various measurement conditions. Based upon observation of the experimental results, the proposed sensor shows a good performance in measuring the shape of transparent plates.