Designing Illumination Optics

Muschaweck, Julius; Rehn, Henning

doi:10.1117/3.2618161

Cited by 6 publications

(3 citation statements)

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“…where dG is the etendue of an infinitesimal portion of light, n the refractive index, dA the infinitesimal surface element the light passes, θ the angle of the light in respect to the surface normal, and dΩ the solid angle the light fills [10,Sec. 2.2].…”

Section: Radiance Requirementsmentioning

confidence: 99%

Flexible illumination module for lab-on-chip applications

Müller,

Ghosh,

Ramsteiner

et al. 2024

Optical Diagnostics and Sensing XXIV: Toward Point-of-Care Diagnostics

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Lab-on-chip analysis for molecular diagnostics use an analyzer unit and cartridges. Since the cartridges are disposables, their development cycle can be much shorter than the one of the analyzer unit. Hence, it is important to have a high degree of flexibility in the analyzer unit to react to new cartridge developments. Our research tries to overcome limitations due to fixed interfaces by replacing a static illumination system for fluorescence analysis by an adjustable module. The benefit of adjustability goes along with harder requirements. In the case of the illumination system, that means a decrease in etendue of the optical system. Purpose of the presented research is to define the spectral radiance requirements on the light source as a bottleneck in an etendue limited optical system. As light source a phosphor converted light source should be used due to the benefits of a broad spectrum. First, the concept of etendue is used to specify a theoretical spectral radiance requirement on the light source. In the second step, the best available light source is used in a prototype to measure the performance of the adjustable illumination system and to derive a practical spectral radiance requirement. With the currently used light source in the lab prototype, requirements are fulfilled for one out of four spectral wavelength bands. The comparison between theory and experiment shows that the theoretical requirement must be corrected by a factor of two to a practical spectral radiance requirement of about 14 mW/(sr • mm 2 • nm). It can be concluded that especially in the blue and red wavelength range below 500 nm and over 600 nm bright phosphor converted light sources are required. Since the time the light source was selected, a new light source candidate with stronger emission for shorter wavelengths was found.

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Section: Radiance Requirementsmentioning

confidence: 99%

Flexible illumination module for lab-on-chip applications

Müller,

Ghosh,

Ramsteiner

et al. 2024

Optical Diagnostics and Sensing XXIV: Toward Point-of-Care Diagnostics

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“…Ray files model the luminance/radiance distribution of a source: how much power is emitted from a small area into a small solid angle, with proper application of the cosine correction factor and the refractive index. 1 This power can be correctly represented in a ray file by many rays with little power or few rays with much power. Both ray file variants should lead to the same virtual focus, which can only be achieved by taking the weights into account.…”

Section: Virtual Focus Definitionmentioning

confidence: 99%

“…For example, to collimate the light from an LED into the far field, one would place the LED at the focal plane of the collimator. Or, to use an LED in Köhler illumination, 1 one would image the LED into the center of the entrance pupil of the second lens, by placing the LED at the conjugate point of the image. The virtual focus then serves as the reference point.…”

Section: Appendix A: Matlab ® Implementationmentioning

confidence: 99%

Virtual focus of a ray data source

Muschaweck¹

2023

Opt. Eng.

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.Ray data files are a common way to model light sources, such as light emitting diodes (LEDs), in optical design software. Often, when an LED shall be placed at the focal point of a collimating lens, it is desirable to know the coordinates of just a single point, which is representative of the light source location, similar to the center of mass for a distribution of matter. In some communities, this point is known as the “virtual focus,” and some LED vendors publish the virtual focus coordinates with their ray data sources. However, it is hard to find a clear and precise definition of the virtual focus, and it is not clear how it can be computed in an efficient way. We explain our definition and provide an efficient algorithm and its MATLAB® implementation.

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