ABSTRACT
This paper presents a miniaturized design of a 2× zoom lens for application to a one-megapixel image sensor in a capsule endoscope. The zoom lens is composed of four lenses, including three plastic aspheric lenses and one glass spherical lens, and adopts a three-lens group design. This capsule endoscope is mainly for observation of the small intestine, which has a radius of about 12.5 mm. The height of the object is thus set to 12.5 mm. The object surface is designed to be curved surface with a radius of curvature of 15 mm. The focal length of the zoom lens ranges from 1.064 mm to 2.039 mm, and the full angle of view ranges from 60° to 143°, the f-number is F/2.8-F/3.5, the zoom lens is 11.6 mm in length, and the maximum effective diameter of the zoom lens is 6 mm. The zoom lens design is divided into six segments, corresponding to the different magnifications from Zoom 1 to Zoom 6. The magnification ratios are -0.0845, -0.0984, -0.1150, -0.1317, -0.1482, and -0.1690, respectively. Comparing the positions from Zoom 1 to Zoom 6, the maximum optical distortion is -14.89% for the Zoom 1 and 1.45% for the Zoom 6. The maximum vertical video distortion is 8.19% for Zoom 1 and 1.00% for Zoom 6. At a 1.0 field of view, the minimum relative illuminance is 71.8% at a magnification of M = -0.1317. Finally, we perform the tolerance analysis and lens resolution analysis at different zooming positions. Our design can obtain high-quality images for capsule endoscope.
ABSTRACT
The aim of this study was to investigate biosynthesis genes and chemical components of the capsule of Avibacterium paragallinarum. The sequence of a 10-kb region containing the capsule biosynthetic locus of Av. paragallinarum was determined. Two reference strains, i.e., 221 (serovar A) and H18 (serovar C), together with four Taiwanese field strains (all serovar C) were sequenced. The results showed that there are two genotypes (I and II) of the capsule biosynthetic locus in Av. paragallinarum, and the capsule genotype is independent of the serovar. The capsule biosynthetic loci of genotypes I and II consisted of six and five genes, respectively. The genotype I genes encoded proteins that are most similar to proteins from Pasteurella multocida capsule types A and F while the genotype II genes encoded proteins most similar to proteins from P. multocida capsule type D and Escherichia coli K5. The results suggested that genotype I strains contain hyaluronan or chondroitin in the capsule wall while genotype II contain heparosan. Enzymatic digestion of the capsule materials extracted from Av. paragallinarum showed that genotype I strains contained chondroitin while genotype II strains contained heparosan in the capsule. This is the first report on the existence of different genotypes of capsule biosynthesis genes in Av. paragallinarum and the presence of chondroitin and heparosan as chemical components of the capsule of Av. paragallinarum.
