The Freeform Reflector for Uniform Rectangular Illumination

Ding, Yi; Gu, Peng; Zheng, Zhou

doi:10.1143/jjap.46.7771

Cited by 15 publications

(14 citation statements)

References 6 publications

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“…According to light transmission energy conservation condition, the output of source is equal to the flux incident in the target plane. Assuming the half viewing angle of the source is (8) where E(t) is the luminance at point t, A is the area illuminated. I(I(φ)) is LED emitting intensity in the direction of I(φ).…”

Section: Energy Conservationmentioning

confidence: 99%

“…When target plane T is fixed, θ and φ can be gotten though Eq. (8). After replacing the corresponding items in Eqs.…”

Section: Energy Conservationmentioning

confidence: 99%

“…In this paper, a new freeform optical lens design method is proposed. Based on the Snell's law and the energy conservation [6][7][8][9], we can deduce from the characteristics of the source and the desired illumination, to get a set of firstorder partial differential equations. By solving these equations numerically, we can get the refractive freeform lens.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Freeform LED lens for uniform illumination

Ding¹,

Liu²,

Zheng³

et al. 2008

Opt. Express

Self Cite

357

192

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Light flux from LED must be redistributed to meet the needs of lighting in most cases, a new method is proposed for its secondary optic design. Based on refractive equation and energy conservation, a set of first-order partial differential equations which represent the characters of LED source and desired illumination were presented. The freeform lens was constructed by solving these equations numerically. The numerical results showed that we can get a freeform lens for the illumination of uniformity near to 90%, with considerable high computation speed. This method can shorten the designing time of the freeform lens with high accepted tolerance.

show abstract

Section: Energy Conservationmentioning

confidence: 99%

“…When target plane T is fixed, θ and φ can be gotten though Eq. (8). After replacing the corresponding items in Eqs.…”

Section: Energy Conservationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Freeform LED lens for uniform illumination

Ding¹,

Liu²,

Zheng³

et al. 2008

Opt. Express

Self Cite

357

192

View full text Add to dashboard Cite

show abstract

“…Although some techniques have been proposed to deal with off-axis illumination problems, such as the partial differential equation (PDE) method, 16 the Monge-Ampère (MA) equation method, 17 equi-flux grids mapping method, 18 and triangular-mesh optimization, 19 a more universal and effective method is still urgently needed. In this paper, a kind of dedicated OI system is presented in order to introduce an effective technique into OI design.…”

Section: Introductionmentioning

confidence: 99%

Design of freeform reflector array for oblique illumination in general lighting

Chen

2015

Opt. Eng

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Downloaded From: http://opticalengineering.spiedigitallibrary.org/ on 08/15/2015 Terms of Use: http://spiedigitallibrary.org/ss/TermsOfUse.aspxAbstract. With increasing concerns about light pollution and energy waste in general lighting, efficient and effective lighting techniques have become imperative. We present the design of a kind of dedicated oblique illumination (OI) system to solve the problems of light pollution and the waste of energy in general lighting. The OI system consists of an extended (actual) light source, a collimator, and a freeform reflector array. Two different layouts of the OI system are proposed for different lighting situations, and design models of the two layouts are also given by use of the Monge-Ampère equation method. Two typical lighting situations, street lighting and advertising board lighting, are given here to illustrate the proposed OI system, and characteristics of the OI system are explored. The results show the light distribution is well controlled with a pretty good optical performance and the OI system has a large tolerance to the change of intensity distribution of the light source and to the size of the light source. Downloaded From: http://opticalengineering.spiedigitallibrary.org/ on 08/15/2015 Terms of Use: http://spiedigitallibrary.org/ss/TermsOfUse.aspx Optical Engineering 065103-2 June 2015 • Vol. 54(6) Chen and Wu: Design of freeform reflector array for oblique illumination in general lighting Downloaded From: http://opticalengineering.spiedigitallibrary.org/ on 08/15/2015 Terms of Use: http://spiedigitallibrary.org/ss/TermsOfUse.aspx Optical Engineering 065103-7 June 2015 • Vol. 54(6) Chen and Wu: Design of freeform reflector array for oblique illumination in general lighting Downloaded From: http://opticalengineering.spiedigitallibrary.org/ on 08/15/2015 Terms of Use: http://spiedigitallibrary.org/ss/TermsOfUse.aspx Optical Engineering 065103-8 June 2015 • Vol. 54(6) Chen and Wu: Design of freeform reflector array for oblique illumination in general lighting Downloaded From: http://opticalengineering.spiedigitallibrary.org/ on 08/15/2015 Terms of Use: http://spiedigitallibrary.org/ss/TermsOfUse.aspx Optical Engineering 065103-10 June 2015 • Vol. 54(6) Chen and Wu: Design of freeform reflector array for oblique illumination in general lighting Downloaded From: http://opticalengineering.spiedigitallibrary.org/ on 08/15/2015 Terms of Use: http://spiedigitallibrary.org/ss/TermsOfUse.aspx

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“…In the first place, uniformity is one of the most important factors for illumination quality as it is essential to achieve a good image signal. A lot of effort has been made to achieve illumination uniformity, mostly by employing sophisticated optical components, such as lens arrays [1], freeform lenses [2], and freeform reflectors [3]. These components can help achieve uniform illumination in particular situations, but not necessarily in a practical optical imaging system where undesired features cannot be neglected, that is, ambient light, uneven target surfaces, inhomogeneous reflection-absorption properties of the target, and so on.…”

Section: Introductionmentioning

confidence: 99%

Approach of self-adaptive illumination for optical imaging systems

et al. 2014

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An optical imaging signal is vulnerable to undesired features such as ambient light illumination and partial specular reflection from the target; the success of extracting target features from images depends largely on appropriate design of illumination. This paper presents an approach for self-adaptive illumination for optical imaging systems. The proposed illumination system projects a reference image to a target surface as an initial structured illumination, and then adjusts the projected image automatically to compensate the negative influences of undesired features. After this self-adaptive control process, undesired features would appear mostly invisible in the captured images. The signal-to-noise ratio would be improved dramatically well before subsequent image processing. In the validation experiments, several images with uniform brightness were offered as reference images; the captured images could achieve high brightness uniformity, even when the target surface was uneven or was illuminated by ambient light. In a further experiment of selective vessel illumination on a human palm, simulated vessel regions were selectively illuminated. Undesired features, like palm prints, almost disappeared in the images captured.

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The Freeform Reflector for Uniform Rectangular Illumination

Cited by 15 publications

References 6 publications

Freeform LED lens for uniform illumination

Freeform LED lens for uniform illumination

Design of freeform reflector array for oblique illumination in general lighting

Approach of self-adaptive illumination for optical imaging systems

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