Nowadays, light emitting diodes (LEDs) have been widely used in backlight module for display technology. Most of researches tend to improve optical performance in specific applications, such as sufficient efficiency, ...
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ISBN:
(纸本)9781628412192
Nowadays, light emitting diodes (LEDs) have been widely used in backlight module for display technology. Most of researches tend to improve optical performance in specific applications, such as sufficient efficiency, desired intensity distribution and high illuminance uniformity. However, most of phosphor converted white LEDs have the problem of inducing impure white light. The undesired phenomenon of yellow ring or blue ring becomes more serious through incorrect secondary opticaldesign. In this paper, we emphasize on enhancing the spatial color and illuminance uniformity of LED direct-lit backlight using nonimaging achromatic lensdesign. We propose a new design method to re-distribute and uniform the ratio of blue and yellow light on the target surface. Moreover, we further apply it in direct-lit LED backlight lensdesign, in which the uniformity of illuminance on the out coupling surface can be as much as 83.7% and the color uniformity (Delta u'v') is improved to 0.0039. Therefore, the result of high color and illumination uniformity can be achieved simultaneously.
The Fine Guidance Sensor (FGS) is part of the science instrumentation for the James Webb Space Telescope (JWST). The FGS is required to operate at 37 K and provide the data needed to facilitate fine pointing and attit...
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ISBN:
(纸本)9780819482822
The Fine Guidance Sensor (FGS) is part of the science instrumentation for the James Webb Space Telescope (JWST). The FGS is required to operate at 37 K and provide the data needed to facilitate fine pointing and attitude stabilization necessary to meet the requirements of the mission's science and engineering operations. We describe here the selection of the proper opticaldesign form to meet requirements and its relative merits. The FGS has progressed with the successful completion of several key design reviews. The opticaldesign of the current stage will be discussed here in detail.
A traditional zoom system is composed of several elements moving relatively toward other components to achieve zooming. Unlike tradition system, an electrically control zoom system with liquid crystal (LC) lenses is d...
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ISBN:
(纸本)9781510612082;9781510612075
A traditional zoom system is composed of several elements moving relatively toward other components to achieve zooming. Unlike tradition system, an electrically control zoom system with liquid crystal (LC) lenses is demonstrated in this paper. To achieve zooming, we apply two LC lenses whose optical power is controlled by voltage to replace two moving lenses in traditional zoom system. The mechanism of zoom system is to use two LC lenses to form a simple zoom system. We found that with such spherical electrodes, we could operate LC lens at voltage range from 31v to 53 v for 3X tunability in optical power. For each LC lens, we use concave spherical electrode which provide lower operating voltage and great tunability in optical power, respectively. For such operating voltage and compact size, this zoom system with zoom ratio approximate 3: 1 could be applied to mobile phone, camera and other applications.
Satellite-based remote sensing offers the best opportunity for studying the properties of atmospheric aerosols and their radiative effects on the global scale over extended periods Tropospheric aerosols represent the ...
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ISBN:
(纸本)0819454613
Satellite-based remote sensing offers the best opportunity for studying the properties of atmospheric aerosols and their radiative effects on the global scale over extended periods Tropospheric aerosols represent the largest uncertainty in predicting the radiative forcing of climate (IPCC, 2001). A key question is whether atmospheric aerosols contribute to warming or cool the climate system. Since the sign of direct radiative forcing is controlled by the ability of aerosol particles to absorb light, the information on the single scattering albedo of different aerosol types and its variations with aerosol lifecycles is clearly very desirable. Furthermore, the wavelength-dependent values of single scattering albedo from the Uv to IR are important in retrieving aerosol optical depth from satellites passive remote sensing and for climate modeling. We describe the design of a space-borne polarimeter that was derived from the key science requirements. The performance of this candidate polarimeter, operating in the Uv/vIS/NIR spectral regions, is described. The opticaldesign form and various optical performance parameters, including transmittance calculations of the polarimeter's spectral channels showing the "leakage" of polarization states, as well as the degree of polarization as function of wavelength and field of view are presented for the various wavelength regions. An overview of the instrument performance and driving operational parameters is presented.
A refractive astigmatic lens is employed to generate a focus error signal (FES) for servo control in general optical pickup. In this paper, a diffractive optical element (DOE) is designed to implement optical function...
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ISBN:
(纸本)9780819468154
A refractive astigmatic lens is employed to generate a focus error signal (FES) for servo control in general optical pickup. In this paper, a diffractive optical element (DOE) is designed to implement optical functions of astigmatic focusing for a MEMS-based miniature optical pickup at 650nm wavelength. We present a diffractive astigmatic lens with its internal zones and external zones quantized into four, two phase levels, respectively based on fabrication consideration. The optical simulation based on scalar diffraction theory shows the efficiency of this quantized lens for astigmatic focusing and a comparison of the FES in the optical pickup system has been plotted.
An overview of optical systems utilized in JPL's optical Communications research is provided here. These include discussions on the flight terminal optics, the ground receiver aperture and the uplink beacon or com...
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ISBN:
(纸本)0819450464
An overview of optical systems utilized in JPL's optical Communications research is provided here. These include discussions on the flight terminal optics, the ground receiver aperture and the uplink beacon or command optical system. On-going efforts on these and beam-coupling techniques will be described.
We present a method for measuring an optical system's effective focal length with a single mode fiber array and a wedge prism. Light emitted by the input fiber near the focal plane is collimated, reflected back in...
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ISBN:
(纸本)0819454613
We present a method for measuring an optical system's effective focal length with a single mode fiber array and a wedge prism. Light emitted by the input fiber near the focal plane is collimated, reflected back in two angularly separated beams, and detected by the output fibers in the auto-collimation configuration. Measurement precision of a Micron can be achieved due to the precision of fiber spacing and the position sensitivity of single-mode coupling. Absolute accuracy depends on factors such as opticaldesign configuration, metrology, aberrations, and environmental control, and can be better than 10 micron. By varying input wavelength and field angle, this technique can be utilized to precisely characterize chromatic dispersion and distortion of the optics. Furthermore, because the technique only requires compact opto-mechanical accessories and electronic apparatus, it can be readily carried out on large optical systems in the field.
Most imaging systems today include a mosaic detector array in the focal plane. opticaldesigners of astronomical telescopes typically produce a design that yields a superb on-axis aerial image in the focal plane, and ...
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ISBN:
(纸本)0819454613
Most imaging systems today include a mosaic detector array in the focal plane. opticaldesigners of astronomical telescopes typically produce a design that yields a superb on-axis aerial image in the focal plane, and detector effects are included only in the analysis of the final system performance. Aplanatic opticaldesigns (corrected for spherical aberration and coma) are widely considered to be superior to non-aplanatic designs. However, there is little merit in an aplanatic design for wide-field applications because one needs to optimize some field-weighted-average measure of resolution over the desired operational field-of-view (OFOv). Furthermore, when used with a mosaic detector array in the focal plane, detector effects eliminate the advantage of the aplanatic design even at small field angles. For wide fields-of-view, the focal plane is frequently despaced to balance field curvature with defocus thus obtaining better overall performance. We will demonstrate that including detector effects in the design process results in a different optimal (non-aplanatic) design for each OFOv that is even superior to an optimally despaced aplanatic design.
The multi-configurative microscopic system for inspecting the wire-bonding of reed frame is designed. Object rays is nearly collimated by a objective lens group which is a common lens group of x2 and x6 imaging lens s...
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ISBN:
(纸本)0819454613
The multi-configurative microscopic system for inspecting the wire-bonding of reed frame is designed. Object rays is nearly collimated by a objective lens group which is a common lens group of x2 and x6 imaging lens systems and is splitted by two beam-splitters composed of a penta-prism and a refracting prism. And object rays started from the central region and the boundary region(reed frame region) on semiconductor chip(that is, the object) are imaged at the two different imaging planes by x2 and x6 imaging lens groups, respectively. The x6 imaging lens system with a constant object distance and a constant magnification is well designed by general imaging optics system design method. However, since the depth of wire structure on the reed frame has about +/-3 mm, in order to observe by a constant magnification and at a fixed imaging plane without the dependency on the variation of objective distance generated by the depth of wire structure on the reed frame, the imaging lens system is composed of two separated groups, which should be moved along nonlinear locus like mechanically compensated zoom lenses. The nonlinear equations for zoom locus are derived by using the Gaussian bracket. Refraction powers and positions of each groups are numerically determined by solving the equations, and initial design data for each groups is obtained by using Seidel third order aberration theory. The optimization technique is finally utilized to obtain this multi-configurative microscopic system.
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