US 8,531,530 B2 · Adjusting method for a lens unit, lens unit and image reading apparatus

Abstract

An adjusting method for a lens unit used in an image reading apparatus which images image information of an original onto an image reading unit by the lens unit and reads the image information, the lens unit including rotationally-symmetrical lenses, a lens barrel including the rotationally-symmetrical lenses and an adjusting lens, the adjusting method including: performing rotational adjustment of the lens barrel with respect to the adjusting lens; and imaging an adjusted chart onto one-dimensional photoelectric transducers via the lens unit, obtaining contrast depth characteristics of images corresponding to at least three angles of field of the lens unit among images of the adjusted chart, and, according to the obtained contrast depth characteristics, performing position adjustment of the adjusting lens in at least one of an array direction of the one-dimensional photoelectric transducers, a direction orthogonal to the array direction and an optical axis direction of the lens unit.

Claims17

Dependent claims

An adjusting method for a lens unit usable in an image reading apparatus that forms images of an original onto one-dimensional photoelectric transducers using the lens unit and reads image information of the original, the lens unit including a plurality of rotationally-symmetrical lenses, a lens barrel including the plurality of rotationally-symmetrical lenses and an adjusting lens disposed at an end portion of the lens barrel, the adjusting method comprising:

a rotational adjustment step of rotational adjusting the lens barrel with respect to the adjusting lens by rotating the lens barrel around symmetry axes of the plurality of rotationally-symmetrical lenses;
and
a contrast depth characteristics obtaining step of obtaining contrast depth characteristics of images of a chart formed on the one-dimensional photoelectric transducers corresponding to at least three angles of field of the lens unit;
and
a positional adjustment step of, according to the contrast depth characteristics obtained in the contrast depth characteristic obtaining step, adjusting a position of the adjusting lens with respect to the lens barrel in at least one of an array direction of the one-dimensional photoelectric transducers, an optical axis direction of the lens unit, or a direction perpendicular to the array direction and the optical axis direction.

2 more elements

A method of producing a lens unit usable in an image reading apparatus that forms images of an original onto one-dimensional photoelectric transducers using the lens unit and reads image information of the original, the lens unit including a plurality of rotationally-symmetrical lenses, a lens barrel including the plurality of rotationally-symmetrical lenses, and an adjusting lens disposed at an end portion of the lens barrel, the method comprising:

a rotational adjustment step of rotationally adjusting the lens barrel with respect to the adjusting lens by rotating the lens barrel around symmetry axes of the plurality of rotationally-symmetrical lenses;
a contrast depth characteristics obtaining step of obtaining contrast depth characteristics of images of a chart formed on the one-dimensional photoelectric transducers corresponding to at least three angles of field of the lens unit;
and
a positional adjustment step of, according to the contrast depth characteristics obtained in the contrast depth characteristics obtaining step, adjusting a position of the adjusting lens with respect to the lens barrel in at least one of an array direction of the one-dimensional photoelectric transducers, an optical axis direction of the lens unit, or a direction perpendicular to the array direction and the optical axis direction.

1 more element

Dependencies are inferred from the claim text.

Adjusting method for a lens unit, lens unit and image reading apparatus

Life of this patent

Adjusting method for a lens unit, lens unit and image reading apparatus

Life of this patent

Abstract

Claims17