In this paper, different opticaldesigns, which are composed of different LWIR optical materials, are utilized for passive athermalization and their performance in athermalization are analyzed. The opticaldesigns are...
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ISBN:
(数字)9781510637719
ISBN:
(纸本)9781510637719
In this paper, different opticaldesigns, which are composed of different LWIR optical materials, are utilized for passive athermalization and their performance in athermalization are analyzed. The opticaldesigns are carried out by preserving the athermal property as well as keeping the image quality at higher levels within the working temperature between -40 degrees C and +60 degrees C. Our designs consist of two different infrared optical elements to maintain the focus positions as stable as possible within the working temperature. The passive athermalization process begins with the calculation of athermalization conditions of candidate material properties. By taking into account these conditions, athermal material pairs are chosen. The opticaldesign begins with an optimization process using paraxial optics. In order to reduce aberrations such as coma, astigmatism, spherical and chromatic, aspherical surfaces are utilized during the optimization process. At the end of the design phase, the performance of different configurations of athermal optical material pairs, which are enclosed by aluminum alloy housing material, are presented.
In the past two decades, to realize high resolutions and low distortions while miniaturizing optical systems, various ultrashort throw lenses (USTs) have been proposed. In this work, ultrashort throw lenses with a cat...
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ISBN:
(数字)9781510637719
ISBN:
(纸本)9781510637719
In the past two decades, to realize high resolutions and low distortions while miniaturizing optical systems, various ultrashort throw lenses (USTs) have been proposed. In this work, ultrashort throw lenses with a catadioptric relay (USTCRs) with rotational symmetry are proposed to provide the solution. First, the initial design method of the USTCR and the optimized design solution are presented. Although this optical system with a throw ratio of 0.26:1 has resolutions and distortions equivalent to those of conventional UST with one aspherical mirror, the depth of focus (DOF) on the panel side becomes 1.31 times deeper with appropriate corrections of the field curvature. The total length of the lens is reduced to 0.89 times, the area of the main mirror is reduced to 0.22 times, and the number of lenses is reduced from 13 to 9 elements. Based on these results, several opticaldesigns for USTCR have been tried and an opticaldesign with robustness has been proposed. By optimizing the power of each lens group, the decenter sensitivity improved to 0.46 times for parallel decenter and 0.55 times for tilt decenter. By optimizing glass materials, the shift of focal plane can be suppressed to 0.56 times when the temperature increases by 30 degrees C. An USTCR suited for a curved screen has also been proposed. By introducing appropriate constraints that correct distortions, high resolutions and low distortions have been realized while maintaining a wide angle of view. USTCRs suited for various curved screens are currently underway.
In conventional imaging, the information transfer from the object to the image plane is accomplished either with the help of a traditional lens that performs a one-to-one mapping or an unconventional lens that perform...
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ISBN:
(数字)9781510637719
ISBN:
(纸本)9781510637719
In conventional imaging, the information transfer from the object to the image plane is accomplished either with the help of a traditional lens that performs a one-to-one mapping or an unconventional lens that performs a one-to-many mapping. In the first case, the image is formed directly, whereas in the second case, the image is formed after a computation. The conventional lens approach is preferred in most cases due to the high signal-to-noise ratio achievable at each image pixel. By appealing to the fact that for most of the imaging applications, it is only the intensity, which is measured by the detector, the phase of the field in the image or focal plane is a free parameter, something that comes from the inverse diffraction transform. Therefore, it is easy to visualize that this phase of the plane wave after it transmits the lens can have multiple forms. Hence, the final choice can be made based upon specific application tailored requirements like achromaticity, depth-of-focus, wide-angle imaging, etc. This concept was exploited to design an achromatic MDL via inverse design across almost the entire electromagnetic spectrum (lambda = 450 nm to 15 mu m). Furthermore, a MDL with a Field Of View (FOV) up to 50 degrees for wide-angle imaging as well as a MDL to enable an extreme Depth of Focus (EDOF) imaging of up to 6 m in the NIR were also designed.
We present the general formula to generated aspheric collimator lens free of spherical aberration and astigmatism. The presented formula describes the second surface of the aspheric singlet such as it correct the sphe...
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ISBN:
(数字)9781510629028
ISBN:
(纸本)9781510629028
We present the general formula to generated aspheric collimator lens free of spherical aberration and astigmatism. The presented formula describes the second surface of the aspheric singlet such as it correct the spherical aberration generated and astigmatism by the first surface of the singlet.
We present an overview of the pros and cons of using GPUs in opticaldesign software. While GPUs can run multiple calculations in parallel, that parallelization comes with a price. We will discuss the trade-offs that ...
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ISBN:
(数字)9781510629028
ISBN:
(纸本)9781510629028
We present an overview of the pros and cons of using GPUs in opticaldesign software. While GPUs can run multiple calculations in parallel, that parallelization comes with a price. We will discuss the trade-offs that allow GPUs to run up to thousands of cores in parallel and how those trade-offs effect the use of GPUs in opticaldesign software. In particular, we review the use of GPUs in several steps of design calculations, including ray-tracing and computationally expensive steps such as calculating Huygens integrals.
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.
Most lensdesign problems involve the time-consuming task of finding a proper starting point, that is, a lensdesign 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 lensdesign problems involve the time-consuming task of finding a proper starting point, that is, a lensdesign 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 lensdesign 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 lensdesign 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 lensdesign structures for which we have no reference lensdesign and obtain a significantly better optical performance than a RNN trained from scratch.
This paper presents the theory for numerical evaluation of the spatial resolution along an optical axis of an optical microscope in case of oblique illumination. It considers the optical setup with a coherent light so...
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ISBN:
(数字)9781510629028
ISBN:
(纸本)9781510629028
This paper presents the theory for numerical evaluation of the spatial resolution along an optical axis of an optical microscope in case of oblique illumination. It considers the optical setup with a coherent light source, a microscope condenser, a grating located in a plane with an optical axis and with grating slits perpendicular to this axis and a microscope objective. It is proposed the analytical expression for calculation of the minimal resolvable period of this grating or the corresponded spatial cutoff frequency that characterizes the spatial resolution along the optical axis. It is demonstrated that this spatial cutoff frequency is not proportional to the angle of beam inclination. The proposed theory clearly explains why an optical microscope has the limited spatial resolution along an optical axis and how illumination can maximize this resolution.
A silicon Fresnel lens was designed and fabricated using a greyscale lithography technique to shape optical emissions from an edge-emitting semiconductor diode laser. The laser beam was collimated in the fast axis and...
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ISBN:
(数字)9781510629028
ISBN:
(纸本)9781510629028
A silicon Fresnel lens was designed and fabricated using a greyscale lithography technique to shape optical emissions from an edge-emitting semiconductor diode laser. The laser beam was collimated in the fast axis and allowed a +/- 3 degrees divergence in the slow axis along with bias angle accomplished through lens decentering. The lens had an aperture of 6.8 mm x 2.2 mm and 1 mm in total thickness. The lens was first designed as a contiguous surface using conventional ray-tracing methods, and then converted to a Fresnel sag model with an etch depth of 6.25 micrometers. The sag model along with the manufacturing tolerances were fed back through numerical tools to refine the design and modify the lens shape and laser position. optical profilometry of fabricated lens element found deviations from design and non-uniformity across the entire aperture, with over-etching in the center and under-etching toward the edge of the lens. Characterization of the fabricated lenses showed less than 5% deviation in etch depth. Collimation performance was measured to be less than 2 milliradians, which was in close agreement with design models. Greyscale fabrication of the lens element enabled complex curvatures to be combined and provided a compact solution for direct, single optic coupling of diode laser to free-space projection.
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