Brightness increase in LED by recycling of light for projection applications

Ouyang, George; Li, Kenneth

doi:10.1117/12.717483

Cited by 5 publications

(3 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The case for mixed recycling is more complicated as both angular and spatial recycling is at work. However, it can be shown that with some simplifying assumptions we can arrive at the same power flow diagram [3]:…”

Section: Mixed Recyclingmentioning

confidence: 99%

14.2: A General Theory of Light Recycling with Light Pipes/Tunnels and Their Applications in LED Illuminators

Ouyang¹,

Li²

2007

Symp Digest of Tech Papers

Self Cite

View full text Add to dashboard Cite

show abstract

Section: Mixed Recyclingmentioning

confidence: 99%

14.2: A General Theory of Light Recycling with Light Pipes/Tunnels and Their Applications in LED Illuminators

Ouyang¹,

Li²

2007

Symp Digest of Tech Papers

Self Cite

View full text Add to dashboard Cite

show abstract

“…The etendue reduction ratio is the ratio of the total area of the output aperture over that of the uncoated window. The principle of enhancing brightness through light recycling has been explained in our previous work 5,6 . For the specific DPR system described above (output etendue = 50 mm 2 *steradian) and with a 4:1 etendue reduction ratio (recycling light pipe etendue = 200 mm 2 *steradian), simulation has shown that 40% of total lumen gain has been achieved.…”

Section: Fig 6 Output Aperture Of the Recycling Light Pipementioning

confidence: 99%

25.2: Invited Paper: Dual Paraboloid Reflector Illumination System for Digital Cinema

Ouyang¹,

Li²

2011

Symp Digest of Tech Papers

Self Cite

View full text Add to dashboard Cite

It has long been demonstrated that, besides extending the life time of UHP lamps, the Wavien patented dual paraboloid reflector (DPR) can also enhance the lamp brightness in the low etendue regime. As a follow-up to our previous work we examine the possibility of extending the same DPR advantages to xenon arc lamps used in digital cinema. With ray tracing, we calculate the throughput efficiencies of a standard compound elliptical reflector used in the industry and a DPR reflector of similar size at various etendue values. The resultant efficiency/etendue curves are plotted and it is shown that, at a typical etendue value of 50 mm 2 *steradian for digital cinema up to 100% brightness improvement can be achieved. Another unique feature of the DPR system is that light recycling can be realized through etendue reduction by a recycling light pipe. Up to 40% recycling gain has been demonstrated with a 1:4 input/output etendue ratio. In addition, it is expected that the lifetime xenon lamps with the DPR can also be extended.

show abstract

“…It can be shown that if one considers light recycling in LED chips, then the extracted light increases with respect to the case in which is disregarded [15,16]. Light recycling can also considerably increase the brightness of LEDs [34,35]. This denotes the importance of both an analysis of light recycling, and a good design of the mirror cup.…”

Section: A Flat Chipmentioning

confidence: 99%

Light-emitting diode spherical packages: an equation for the light transmission efficiency

2009

View full text Add to dashboard Cite

Virtually all light-emitting diodes (LEDs) are encapsulated with a transparent epoxy or silicone gel. Here we analyze the optical efficiency of spherical encapsulants. We develop a quasi-radiometric equation for the light transmission efficiency, which incorporates some ideas of Monte Carlo ray tracing into the context of radiometry. The approach includes the extended source nature of the LED chip and the chip radiance distribution. The equation is an explicit function of the size and the refractive index of the package, and also of several chip parameters such as shape, size, radiance, and location inside the package. To illustrate the use of this equation, we analyze several packaging configurations of practical interest, for example, a hemispherical dome with multiple chips, a flat encapsulation as a special case of the spherical package, and approximate calculations of an encapsulant with a photonic crystal LED or a photonic quasi-crystal LED. These calculations are compared with Monte Carlo ray tracing, giving almost identical values.

show abstract

Brightness increase in LED by recycling of light for projection applications

Cited by 5 publications

References 1 publication

14.2: A General Theory of Light Recycling with Light Pipes/Tunnels and Their Applications in LED Illuminators

14.2: A General Theory of Light Recycling with Light Pipes/Tunnels and Their Applications in LED Illuminators

25.2: Invited Paper: Dual Paraboloid Reflector Illumination System for Digital Cinema

Light-emitting diode spherical packages: an equation for the light transmission efficiency

Contact Info

Product

Resources

About