Illumination angle

About: Illumination angle is a research topic. Over the lifetime, 859 publications have been published within this topic receiving 7423 citations.

The Amsterdam Library of Object Images

Abstract: We present the ALOI collection of 1,000 objects recorded under various imaging circumstances. In order to capture the sensory variation in object recordings, we systematically varied viewing angle, illumination angle, and illumination color for each object, and additionally captured wide-baseline stereo images. We recorded over a hundred images of each object, yielding a total of 110,250 images for the collection. These images are made publicly available for scientific research purposes.

Fundamental principles of optical lithography

Abstract: 1.3. Mask Illumination Purpose: The purpose of this section is to describe how masks are illuminated in lithographic imaging systems and how this illumination affects image formation. Objectives: Upon completion of this section, you will be able to:  Describe the effect of illumination angle on the diffraction pattern  Define partial coherence  Describe the impact of illumination on resolution  Define Kohler illumination

Lens-free optical tomographic microscope with a large imaging volume on a chip

Abstract: We present a lens-free optical tomographic microscope, which enables imaging a large volume of approximately 15 mm3 on a chip, with a spatial resolution of < 1 μm × < 1 μm × < 3 μm in x, y and z dimensions, respectively. In this lens-free tomography modality, the sample is placed directly on a digital sensor array with, e.g., ≤ 4 mm distance to its active area. A partially coherent light source placed approximately 70 mm away from the sensor is employed to record lens-free in-line holograms of the sample from different viewing angles. At each illumination angle, multiple subpixel shifted holograms are also recorded, which are digitally processed using a pixel superresolution technique to create a single high-resolution hologram of each angular projection of the object. These superresolved holograms are digitally reconstructed for an angular range of ± 50°, which are then back-projected to compute tomograms of the sample. In order to minimize the artifacts due to limited angular range of tilted illumination, a dual-axis tomography scheme is adopted, where the light source is rotated along two orthogonal axes. Tomographic imaging performance is quantified using microbeads of different dimensions, as well as by imaging wild-type Caenorhabditis elegans. Probing a large volume with a decent 3D spatial resolution, this lens-free optical tomography platform on a chip could provide a powerful tool for high-throughput imaging applications in, e.g., cell and developmental biology.

Fiber based organic photovoltaic devices

Abstract: A fiber-shaped organic photovoltaic cell is demonstrated, utilizing concentric thin films of small molecular organic compounds. Illuminated at normal incidence to the fiber axis through a thin metal electrode, the cell exhibits 0.5% power conversion efficiency, compared to 0.76% for a planar control device. The fiber device efficiency is nearly independent of illumination angle, increasing its power generation over the planar counterpart for diffuse illumination. Losses due to partial shading of the fiber surface are minimal, while the coated fiber length is limited only by the experimental deposition chamber geometry—factors favoring scale-up to woven energy harvesting textiles.

Understanding the forbidden pitch and assist feature placement

Abstract: Optical proximity effect is a well-known phenomenon in photolithography. Such an effect results from the structural interaction between the main feature and the neighboring features. Recent observations have shown that such structural interactions not only affect the critical dimension of the main feature at the image plane, but also the exposure latitude of the main feature. In this paper, it has been shown that the variation of the critical dimension as well as the exposure latitude of the main feature is a direct consequence of light field interference between the main feature and the neighboring features. Depending on the phase of the field produced by the neighboring features, the main feature critical dimension and exposure latitude can be improved by constructive light field interference, or degraded by destructive light field interference. The phase of the field produced by the neighboring features can be shown to be in the location where the field produced by the neighboring features can be shown to be dependent on the pitch as well as the illumination angle. For a given illumination, the forbidden pitch lies in the location where the field produced by the neighboring features interferes with the field of the main feature destructively. The theoretical analysis given here offers the tool to map out the forbidden pitch locations for any feature size and illumination conditions. More importantly, it provides the theoretical ground for illumination design in order to suppress the forbidden pitch phenomenon, and for scattering bar placement to achieve optimal performance as well.