A contour calculation method for rapid freeform reflector construction with ellipsoid patches

This paper presents a field curvature correction method of designing an ultrashort throw ratio (TR) projection lens for an imaging system. The projection lens is composed of several refractive optical elements and an odd polynomial mirror surface. A curved image is formed in a direction away from the odd polynomial mirror surface by the refractive optical elements from the image formed on the digital micromirror device (DMD) panel, and the curved image formed is its virtual image. Then the odd polynomial mirror surface enlarges the curved image and a plane image is formed on the screen. Based on the relationship between the chief ray from the exit pupil of each field of view (FOV) and the corresponding predescribed position on the screen, the initial profile of the freeform mirror surface is calculated by using segments of the hyperbolic according to the laws of reflection. For further optimization, the value of the high-order odd polynomial surface is used to express the freeform mirror surface through a least-squares fitting method. As an example, an ultrashort TR projection lens that realizes projection onto a large 50 in. screen at a distance of only 510 mm is presented. The optical performance for the designed projection lens is analyzed by ray tracing method. Results show that an ultrashort TR projection lens modulation transfer function of over 60% at 0.5 cycles/mm for all optimization fields is achievable with f-number of 2.0, 126° full FOV, <1% distortion, and 0.46 TR. Moreover, in comparing the proposed projection lens' optical specifications to that of traditional projection lenses, aspheric mirror projection lenses, and conventional short TR projection lenses, results indicate that this projection lens has the advantages of ultrashort TR, low f-number, wide full FOV, and small distortion.

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“…The entire convex mirror surface is assembled by hyperbolic segments. Thus, it can be written as [25] R mirror surface ⋃ P k1 A k ;…”

Section: B Design Of the Odd Polynomial Mirror Surfacementioning

confidence: 99%

Field curvature correction method for ultrashort throw ratio projection optics design using an odd polynomial mirror surface

Zhuang

Chen

et al. 2014

Appl. Opt.

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Novel non-imaging optic design for uniform illumination

et al. 2016

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Multi-element direct design using a freeform surface for a compact illumination system

2017

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An iterative optimization algorithm is introduced to address the surface iterative errors as well as source extension issues in a freeform illumination system for producing satisfactory illumination distribution. A unique two-parameter coordinate system is utilized to represent the emitted ray directions. Then, the direction vector for the incident rays, which propagate through several surfaces, is obtained using ray-tracing techniques. Based on the mapping between the incoming rays and a target grid, a freeform surface is generated as a good starting design. An iterative optimization strategy is further employed to alleviate the deterioration of illumination distribution on the target region, and the uniformity of the illumination system is evaluated during optimization. Very few variables are demanded, and more flexibility in the design of the freeform surface is offered. Successive iterations can be performed until the desired result is attained. An optical system is used as an example to demonstrate the validity of the proposed method, and numerical simulations are carried out to evaluate the optical performance. The simulation results show that a small angular intensity distribution and prescribed rectangular illumination pattern can be achieved simultaneously.

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A contour calculation method for rapid freeform reflector construction with ellipsoid patches

Cited by 3 publications

References 22 publications

Field curvature correction method for ultrashort throw ratio projection optics design using an odd polynomial mirror surface

Field curvature correction method for ultrashort throw ratio projection optics design using an odd polynomial mirror surface

Novel non-imaging optic design for uniform illumination

Multi-element direct design using a freeform surface for a compact illumination system

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