Miniature optics are used in many applications and particularly in consumer optics for such products as webcams, mobile phones, automotive components, endoscopes, tablets, and many other connected devices. Mobile phon...
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ISBN:
(数字)9781510629028
ISBN:
(纸本)9781510629028
Miniature optics are used in many applications and particularly in consumer optics for such products as webcams, mobile phones, automotive components, endoscopes, tablets, and many other connected devices. Mobile phone cameras are probably the ones that have driven the race for shorter TTL over the past 10 years. Ten years ago, cell phone cameras were composed of 3-4 optical plastic elements within one camera lens;today it takes more than 6 optical elements to obtain mega pixel resolution. But it is still not enough. The market has an insatiable appetite for greater optical performance. Consequently, the lens system has become more complex and now may require more optical elements with more complex optical functions. In this context, can the metasurface lens play a role? In this paper, we will try to address this question and discuss how metasurfaces promise to become a game changer in the consumer electronics market.
This study presents a new method for selecting a pair of optical glass and housing material to achromatize and athermalize a lens system, by use of the factor of determination for material selection. To effectively ob...
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ISBN:
(数字)9781510629028
ISBN:
(纸本)9781510629028
This study presents a new method for selecting a pair of optical glass and housing material to achromatize and athermalize a lens system, by use of the factor of determination for material selection. To effectively obtain an optimum combination for materials, we newly propose the sequential material selection method by introducing the factor of determination for material selection, which depends on the level of contribution to correct these aberrations and the availability to be used as a suitable material. Even though there are many cases for material combinations, we can sequentially identify the best pair of glass and housing materials by checking the factor of determination. Using this design approach, we efficiently obtain an achromatic and athermal system through an optimum combination of materials, over the specified ranges in temperature and waveband.
We proposed a novel structure to perform photon recycling for a double-light-source illumination system pumped by a laser. In the design, two kinds of phosphor are located at the two focus of an elliptical reflective ...
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ISBN:
(数字)9781510629028
ISBN:
(纸本)9781510629028
We proposed a novel structure to perform photon recycling for a double-light-source illumination system pumped by a laser. In the design, two kinds of phosphor are located at the two focus of an elliptical reflective surface separately, after the phosphor on the first focus pumped by laser, the backward scattering light will refocus at the other phosphor layer at the second focus. The absorption spectrum of the second phosphor should fit that of the emission light by the first phosphor. When the emission spectrum covers red light, the whole system is a double-light-source module.
Minimal refractive index data in the near-infrared spectrum are available for optical plastics. Typically, refractive index measurements are made by fabricating a prism of candidate optical material and using appropri...
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ISBN:
(数字)9781510629028
ISBN:
(纸本)9781510629028
Minimal refractive index data in the near-infrared spectrum are available for optical plastics. Typically, refractive index measurements are made by fabricating a prism of candidate optical material and using appropriate metrology equipment. Few plastics are available in thicknesses adequate to fabricate appropriate size prisms;however, almost all optical plastics can be acquired in a flat plate form. The investigation considered two fundamental approaches to measure the refractive index by (i) rotating a flat plate and measure the beam displacement and ( ii) measuring the optical focal shift. The rotation method was determined not accurate enough. An optical focal shift method optical(n = t(optical)/t(mechanical)) was developed that utilized existing laboratory equipment. The shift of focus when the plastic plate sample was inserted was located by determining the position of maximum contrast of the projection of a Ronchi ruling target when illuminated by flux from a Cary Eclipse covering the spectral range of 550-975 nm. The instrumentation, data processing, and measurement performance are presented.
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 f...
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ISBN:
(数字)9781510629028
ISBN:
(纸本)9781510629028
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.
A head-mounted display (HMD) requires a large field of view (FOV) and a large exit pupil diameter while maintaining a compact structure. In this paper, we show a head-mounted display design comprising two freeform mir...
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ISBN:
(数字)9781510629028
ISBN:
(纸本)9781510629028
A head-mounted display (HMD) requires a large field of view (FOV) and a large exit pupil diameter while maintaining a compact structure. In this paper, we show a head-mounted display design comprising two freeform mirrors covering a 28 degrees full field-of-view with an eye relief of 15mm. The simplified partial differential equation (PDE) method is applied in the design of a two-mirror HMD system. Then the data points on the unknown freeform mirrors are calculated using the rays from multiple fields and are used to construct the freeform mirrors in the HMD system, which is taken as a starting point. This simplified partial differential equation method makes calculations easier. The anamorphic surface and the XY polynomial freeform surface are used in the two freeform mirrors for improving the image quality, respectively. The optimization strategy is also described in detail. The final HMD system operates at F/3.75 with 8mm exit pupil diameter achieving good imaging performance.
Most lens design problems involve the time-consuming task of finding a proper starting point, that is, a lens design that approximately fulfills the desired first-order specifications while decently correcting aberrat...
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ISBN:
(数字)9781510629028
ISBN:
(纸本)9781510629028
Most lens design problems involve the time-consuming task of finding a proper starting point, that is, a lens design that approximately fulfills the desired first-order specifications while decently correcting aberrations. In recent work, a fully-connected (FC) deep neural network was trained to learn this task by extrapolating from known lens design databases. Here, we introduce a new dynamic neural-network architecture for the starting point problem which is based on a recurrent neural network (RNN) architecture. As we show, the dynamic network can learn to infer good starting points on many lens design structures at once whereas the previous model was limited to a given sequence of glass elements and air gaps. We also show that a pretrained RNN model can generalize its knowledge over new lens design structures for which we have no reference lens design and obtain a significantly better optical performance than a RNN trained from scratch.
Directed energy propulsion for interstellar travel has been proposed as an ideal method for reaching appreciable speeds relative to the speed of light: 0.2c. However, the amount of energy required necessitates a large...
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ISBN:
(数字)9781510629028
ISBN:
(纸本)9781510629028
Directed energy propulsion for interstellar travel has been proposed as an ideal method for reaching appreciable speeds relative to the speed of light: 0.2c. However, the amount of energy required necessitates a large aperture, on the order of kilometers, while mitigation of atmospheric perturbations requires a discretization of the aperture into many individual laser elements. The use of fiber lasers for these elements obligates mode-matching the fiber to the desired 10 cm aperture for a collimated beam. Various collimation systems were designed and compared. A 3-lens system with one achromat and two aspheric lenses, with two of the lenses used as a Keplerian telescope to achieve a system-shortening effect was analyzed. A similar system made with a plano-convex lens replacing the large-aperture aspheric lens with two additional compensating lenses was compared. A single diffractive optic operating at F/8 was likewise considered. The optical performance of these systems was compared, as was the cost-effectiveness. Scalability to millions of elements was required, so cost-per-system was a crucial consideration factor. Possible manufacturing processes for a diffractive system were investigated, and stamping processes for replication were analyzed to determine the possibility of replication of such an optic reliably, cheaply, and with acceptable results.
CMOS technologies have swiftly ameliorated across the past few years. To meet the demand of high performance applications like compact disc players, high definition television (HDTV), radar, medical imaging etc., this...
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ISBN:
(纸本)9781728120683
CMOS technologies have swiftly ameliorated across the past few years. To meet the demand of high performance applications like compact disc players, high definition television (HDTV), radar, medical imaging etc., this employs info conversion system for processing at later stages. Accuracy is highly desirable in many functional systems like optical communication, military surveillance etc. In optical communication system, transimpedance amplifier (TIA) is the fundamental part of optical receiver which is required to convert the low level current signal from the photodiode to an operable output voltage for further processing. Here in this paper, we propose a CMOS TIA using class-AB flipped voltage follower having less output resistance. Simulation results of the proposed circuit in 0.18 mu m technology depicts that the bandwidth and the transimpedance gain obtained are increased by 3.3 times and 1.03 times respectively.
In this paper, a primary lens of concentrator photovoltaic (CPV) system is designed by using freeform optics. The designed lens is constructed based on a basic idea of a combination of Fresnel lens and freeform optics...
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ISBN:
(数字)9781510629028
ISBN:
(纸本)9781510629028
In this paper, a primary lens of concentrator photovoltaic (CPV) system is designed by using freeform optics. The designed lens is constructed based on a basic idea of a combination of Fresnel lens and freeform optics, in which the lens is divided into an array of sub-lenses, which are designed using the conservation of optical path length and the edge ray theorem to get uniform irradiance distribution over the receiver. In this design, every sub-lens is designed to guide the direct sunlight over the receiver with uniform irradiance so that the whole of the primary lens will converge uniformly the direct sunlight over the receiver. The structure of the lens is designed firstly by using Matlab program for every sublens. The Matlab data of the designed lens structure is then used to build the three-dimensional (3D) lens in LightTools (TM) software. The ray tracing technique in LightTools (TM) software is used to find out the optimum structure of the freeform lens. Furthermore, the simulation is performed to estimate the efficiency of the lens as a concentrator of a CPV system by using the light source with the sunlight spectrum. The designed lens can achieve high geometrical concentration ratio and uniform irradiance distribution over the receiver. The simulation results show that the lens can easily reach a high concentration ratio (494 times) with uniform irradiance distribution and good optical efficiency (86%).
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