Aspheric mould design includes the top-down design and reversal design. In this paper, a new framework of reversal
design is proposed combining with cloud supported collaborative design (CSCD) based on aspheric measurement. The
framework is a kind of collaborative platform, which is composed of eight modules, including the computerized aspheric precision measurement module (CAPM), computer-aided optical design of aspheric lens system (CAOD),
computer-aided design of lens mould (CADLM), FEM(finite element method) simulation of lens molding module
(FEMLM), computer-aided manufacture of lens and moulds (CAMLM), measurement data analysis module (MDAM),
optical product lifecycle management module (OPLM) and cloud computing network module (CCNM). In this framework, the remote clients send an improved requirement or fabrication demand about optical lens system through CCNM, which transfers this signal to OPLM. In OPLM, one main server is in charge of the task distribution and
collaborative work of other six modules. The first measurement data of aspheric lens are produced by clients or our proposed platform CAPM, then are sent to CAOD for optimization and the electronic drawings of lens moulds are generated in CADLM module. According the design drawings, the FEMLM could give the lens-molding simulation
parameters through FEM software. The simulation data are used for the second design of moulds in CADLM module. In this case, the moulds could be fabricated in CAMLM by ultra-precision machine, and the aspheric lens could be also
produced by lens-molding machine in CAMLM. At last, the final shape of aspheric lens could be measured in CAPM and the data analysis could be conducted in MDAM module. Through the proposed framework, all the work described
above could be performed coordinately. And the optimum design data of lens mould could be realized and saved, then shared by all the work team.
Lens molding has become the promising technique to conduct mass produce of aspheric glass lens. It overcomes some
disadvantages of traditional grinding or turning methods, such as high cost, low efficiency, unstable accuracy, and so on.
Up to now, the lens molding process has been looked on as one of the reliable methods in fabrication of aspheric glass
lens. However, in real production, one has found that it’s hard to control the molding parameters, e.g. molding
temperature, molding period, molding speed and pressing pressure, etc. Therefore it’s necessary to develop the specific
molding processes for a certain glass material. In this paper, SCHOTT P-SK57 is adopted to carry out the lens molding
analysis in order to achieve the relative processing parameters. The molding cases are analyzed based on three different
temperatures of 510°C, 520°C, and 530°C, higher than transition point 493°C of P-SK57. Through continuous heating
and pressing simulation, the results show that the best pressing temperature could be about 530°C, at which the residual
stress is only 5.22MPa (with the molding speed of 0.1mm/s).
Single crystal germanium is used in infrared spectroscopes and other optical equipment as an excellent infrared optical
material. The development of germanium Fresnel lenses not only improves the optical imaging quality but also enables
the miniaturization of optical systems. In a previous work, a Fresnel lens with precise curvatures, sharp edges and precise
cross-sectional profiles were fabricated. However, sometimes, microcracks will occur to the edge of grooves when the
wear of the diamond tool is large in the machining process. In the present work, in order to minimize the effect of the
tool tip wear to the groove edge of Fresnel lens, a novel machining process and machining conditions are proposed for
fabricating a high-precision Fresnel lens.
A novel car camera lenses have been designed. To reduce the cost, the system gives up the glued lenses. The whole
optical system is made of six separated lenses and an IR-Cut Filter, among which there is two aspheric lenses and four
spherical lenses. All lenses are made of glass. The resolutions of car camera system is three million pixels and the field
angle is 150°.The Tangential MTF is 0.2 at spatial frequency of 300 cycles/mm when field angle is equal to 150°. The
axis MTF is 0.7 at spatial frequency of 150 cycles/mm. The overall length of system is 18.23mm. The F-number is 2.8
and the effective focus length is 1.6mm. The new-designed car camera lenses can provide high-resolutions and very wide
field angle. At the same time, the glass structure of lenses enjoys better thermal and mechanical stability than polymer
lenses. The novel car-camera lenses will be then tested in the experiment.
KEYWORDS: Digital holography, Holograms, 3D image reconstruction, Phase shifts, Digital imaging, Demodulation, Digital recording, Charge-coupled devices, CCD image sensors, Holography
A novel one-shot in-line digital holography based two-dimensional Hilbert demodulation is proposed. By weakening the
object wave compared with the reference wave and applying natural logarithmized operation on the in-line digital
hologram, the real part of object wave can be well extracted. Then utilizing two-dimensional Hilbert transform to
digitally realize π / 2 phase-shift makes it possible to reconstruct the object wave front from single-exposure in-line
digital hologram. Preliminary experimental results are presented to demonstrate the proposed method. This technique
can be used for real time imaging and monitoring moving objects.
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