We fabricated transmissive optical diffusers with a randomized concavo-convex surface that was designed to control the irradiation distribution and can be fabricated easily. The diffusers were molded from acrylic using the mold cores machined by ultraprecision cutting or milling. Less stray light was observed from the diffuser molded with the cutting core compared with the milling core. As the Fourier optics simulation was consistent with the measured distribution, it was beneficial for the design evaluation of diffusers. Furthermore, we molded a Penrose-tiling micro-lens-array to generate uniform light distribution without random displacement of each lens. The measurement results showed the feasibility of the Penrosetiling micro-lens-array as a diffuser.
We report on an axially asymmetric beam shaping optical system including a diffraction grating. This optical system
compensates the astigmatism introduced by change in wavelength of a light source or change in ambient temperature.
The phase function of the diffraction grating is determined to minimize the astigmatism by equalizing variation in
distance from a light source to an image point on xz plane and variation in that distance on yz plane. This beam shaping
optical system relates to a laser printer having an axially asymmetric profile.
There are many features expected by printer users, which include high resolution, low price, compact size, color, high
speed printing and so on. Laser printers generally utilize a polygon mirror as a reflector in their optical configurations,
but the usual size of the polygon mirror prevents laser scanning unit from being made much smaller. We have been
conducting research on techniques which can contribute to reducing the optical unit size. Although oscillating mirror
made with MEMS technology enables the system to be compact, it requires a sophisticated optical design having an
increased number of constraints due to the change in angular velocity which varies depending on the orientation of the
mirror, while the polygon mirror allows the scanning with constant speed. Using a small MEMS mirror is one of the
critical issues concerning the reduction of cost. We have successfully resolved all the challenges listed above by using
high-precision free-form optical surfaces and an optical layout making efficient use of 3D space. Our techniques can
make the unit size much smaller and reduce the price. The optical path is designed to have a ray passing through a lens
twice. We report both theoretical and experimental results for this system.
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