Freeform surface lens for LED uniform illumination

Zheng, Zhou; Hao, Xiang; Liu, Xü

doi:10.1364/ao.48.006627

Cited by 131 publications

(54 citation statements)

References 9 publications

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“…[4,5] 이러한 문제를 극복하기 위해 단일 광학 소자인 자유 형상 렌즈(freeform lens)를 2차 광학 소자로 활용하는 방안이 제 안되었으며, [6] 관련 설계 방법에 대한 연구도 활발히 진행되 어 왔다. [12] . 그러나, 자유 형상 렌즈는 설정된 광원 특성에 맞춰 그 형상 이 최적화되므로, LED 광원의 방출 특성이나 배치 등이 설 계 조건으로부터 벗어날 경우 일반 렌즈에 비해 성능이 크게 저하될 여지가 있다.…”

Section: 서 론unclassified

Variation of Illumination Performance with Source Size and Tolerance Characteristics of Freeform LED Lenses

양재석¹,

김대찬²,

오범환³

et al. 2013

Korean Journal of Optics and Photonics

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Variation of Illumination Performance with Source Size and ToleranceCharacteristics of Freeform LED Lenses In this paper, the illumination performances of three freeform lenses optimally designed for a point source were investigated for several LEDs with different source sizes, and also the tolerance characteristics of the lenses were analyzed. For comparison, two lenses with different sizes were designed with a divergent illumination model, and the last one was done with an overlapped illumination model. As the LED source size increased, the illuminance uniformity decreased more strongly, and the influence of a source misalignment on illumination performance became insignificant. However, the variation of LED radiation characteristics had strong effect on the illumination performance, irrespective of LED source size. Even though the lens based on a divergent illumination model showed superior performance compared to the lens based on an overlapped illumination model, the latter was less sensitive to the variation of LED radiation characteristics.

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Section: 서 론unclassified

Variation of Illumination Performance with Source Size and Tolerance Characteristics of Freeform LED Lenses

양재석¹,

김대찬²,

오범환³

et al. 2013

Korean Journal of Optics and Photonics

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“…First of all, the ray transportation must satisfy the energy conservation among coordinate transformation. 14,15 The radiant intensity I (Watts∕sr) of a point source (in polar domain Ω θ ) and prescribed illuminance distribution E (Watts∕m 2 ) of the target region (in Cartesian domain Ω x ), in one dimension, can be related as Z…”

Section: Freeform Model In Localized Pdementioning

confidence: 99%

New approach to construct freeform surface by numerically differential formulation

et al. 2013

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Abstract. We proposed a new design method for single freeform reflective (or refractive) surface tailored to redistribute the radiant flux onto a prescribed illumination pattern. Unlike the conventional optimization approaches based on the grid mapping, in this study we estimated each segmental freeform surface by locally solving a second-order differential equation, which formulates the energy transportation between each domain cell. With finite element method via Hermite element, we validated a series of smooth reflective/refractive surfaces to reallocate the radiant flux from a point source toward a target plane with specific patterns. The proposed technique offers a large flexibility by varying the vectors of each ray with multiple refraction (or reflection), which imposes no restriction on the target distribution, collective solid angle, or even target topography.

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“…Free-form imaging optics is also present in the design of enhanced imaging systems ranging from high aspect on-axis systems [3] to both optical [4] and catoptrical [5] photographic lenses. The main applications of non-imaging optical systems with free form surfaces are illumination systems [6] and solar concentrators [7]. The usage of free-form surfaces allows for a greater number of degrees of freedom for the optical designer enabling, in this way, the design of enhanced optical systems.…”

Section: Introductionmentioning

confidence: 99%

Design and development of a profilometer for the fast and accurate characterization of optical surfaces

et al. 2015

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With the advent of techniques devised for the mass production of optical components made with surfaces of arbitrary form (also known as free form surfaces) in the last years, a parallel development of measuring systems adapted for these new kind of surfaces constitutes a real necessity for the industry. Profilometry is one of the preferred methods for the assessment of the quality of a surface, and is widely employed in the optical fabrication industry for the quality control of its products. In this work, we present the design, development and assembly of a new profilometer with five axis of movement, specifically suited to the measurement of medium size (up to 150 mm of diameter) "free-form" optical surfaces with sub-micrometer accuracy and low measuring times. The apparatus is formed by three X, Y, Z linear motorized positioners plus and additional angular and a tilt positioner employed to locate accurately the surface to be measured and the probe which can be a mechanical or an optical one, being optical one a confocal sensor based on chromatic aberration. Both optical and mechanical probes guarantee an accuracy lower than the micrometer in the determination of the surface height, thus ensuring an accuracy in the surface curvatures of the order of 0.01 D or better. An original calibration procedure based on the measurement of a precision sphere has been developed in order to correct the perpendicularity error between the axes of the linear positioners. To reduce the measuring time of the profilometer, a custom electronics, based on an Arduino TM controller, have been designed and produced in order to synchronize the five motorized positioners and the optical and mechanical probes so that a medium size surface (around 10 cm of diameter) with a dynamic range in curvatures of around 10 D, can be measured in less than 300 seconds (using three axes) keeping the resolution in height and curvature in the figures mentioned above.

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Freeform surface lens for LED uniform illumination

Cited by 131 publications

References 9 publications

Variation of Illumination Performance with Source Size and Tolerance Characteristics of Freeform LED Lenses

Variation of Illumination Performance with Source Size and Tolerance Characteristics of Freeform LED Lenses

New approach to construct freeform surface by numerically differential formulation

Design and development of a profilometer for the fast and accurate characterization of optical surfaces

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