An image reading unit includes an illumination portion, a reading portion, a casing, and a reflection member including a reflecting surface. The casing is provided with an opening. The reflection member is held outside of the opening of the casing so that at least a part of the reflecting surface is exposed to the inside of the casing through the opening.

A reflective member is disposed on the optical path from the linear light source to the lens array. An ultraviolet light blocking filter is provided closer to a light-receiving unit than the reflective member. A color filter is provided closer to the light-receiving unit than the ultraviolet light blocking filter. A light-receiving surface of the light-receiving unit has a first region opposed to the reflective member without the ultraviolet light blocking filter and the color filter interposed therebetween, a second region opposed to the reflective member and the ultraviolet light blocking filter without the color filter interposed therebetween, and a third region opposed to the reflective member, the ultraviolet light blocking filter, and the color filter.

By overlapping lighting timings of light sources that emit lights of a plurality of different wavelength bands including a wavelength band of at least a visible light region and an infrared light region, the lights of the plurality of the different wavelength bands including the wavelength band of at least the visible light region and the infrared light region are emitted on a banknote while securing an overlap in timings thereof. Moreover, by using light receiving elements each including a bandpass filter that allows only light of a wavelength range that corresponds to the wavelength band of each of the light sources, received light intensities of the light of the wavelength range that corresponds to the wavelength band of each of the light sources are acquired simultaneously, and image data are formed based on the received light intensity of every acquired wavelength band.

An optical device detachably disposed on a scanner is provided, including a housing, a first opening, a second opening, a lens module, and a fixing member. The housing has a first surface and a second surface connected to the first surface. The first opening and the second opening are respectively formed on the first surface and the second surface. The lens module is disposed in the housing. The fixing member is detachably affixed to the scanner and pivotally connected to the housing. The light provided by the scanner enters the housing through the first opening, and the lens module guides the light to leave the housing through the second opening. The light leaving the housing through the second opening can fall on a scanned object.

An image reading apparatus includes a reader, a transmitter, an opposing part that is placed opposite to the transmitter, and a hardware processor that controls a position of the opposing part such that a gap between the transmitter and the opposing part becomes a first gap when images are read by the reader, and a gap between the transmitter and the opposing part becomes a second gap, which is wider than the first gap, when no image is read by the reader.

A method and device for the optical scanning of a chromatographic sample (3), where a sample plate (2) holding the sample (3) is illuminated with light from a first illumination device (13) and the light emitted by the sample plate (2) is detected by an optical detector device (15) which detects in cell form or area form, a second illumination device (14) is preferably firstly activated in a preparation step. The sample plate (2) is displaced in a first displacement direction relative to the detector device (15), illuminated by the first illumination device (13) and a first measurement image is recorded. The sample plate (2) is displaced in a second displacement direction relative to the detector device (15), illuminated by the second illumination device (14), and a second measurement image is recorded.

An image sensor unit includes: a linear light source that illuminates a document with a light; a first erecting equal-magnification lens array and a second erecting equal-magnification lens array arranged in the stated order away from the document so as to receive a light reflected from the document and form an erecting equal-magnification image; a slit provided on an intermediate imaging plane between the first erecting equal-magnification lens array and the second erecting equal-magnification lens array; a diffraction grating that disperses a light output from the second erecting equal-magnification lens array; and a linear image sensor that receives a light dispersed by the diffraction grating.

An image reading device (100) includes a first glass member (52), a plurality of condensing lenses (14) provided on a first surface (52a) of the first glass member (52), a first light blocking member (12) having a plurality of first openings (32) respectively corresponding to the plurality of condensing lenses (14), a second glass member (51) having a third surface (51a) in superimposition with the first light blocking member (12), a second light blocking member (11) having a plurality of second openings (31) respectively corresponding to the plurality of first openings (32), a third glass member (53) having a fifth surface (53a) in superimposition with the second light blocking member (11), a third light blocking member (15) having a plurality of third openings (34) respectively corresponding to the plurality of second openings (31), and a sensor unit (3) having a sensor substrate (9) and a plurality of light receiving pixels (10) arrayed in a predetermined array direction on the sensor substrate (9) and respectively corresponding to the plurality of third openings (34).

An optical device includes: a lens body including plural lenses arranged such that optical axes of the plural lenses extend along each other; and a light-blocking body disposed on a light incident side of the lens body and including light-transmitting portions that transmit light and light-blocking portions that block light, the light-transmitting portions and the light-blocking portions being continuously arranged in an alternating manner such that the light-transmitting portions are positioned at the plural lenses and that the light-blocking portions are positioned between the plural lenses.

An image reading apparatus includes: a reader that performs first reading of reading a document and second reading of reading a portion read through a first color in the first reading through a second color using an area sensor having a Bayer arrangement color filter; a generator that generates first image data represented by a plurality of adjacent pixels with a read value obtained through one Bayer arrangement in the first reading as one pixel, and generates second image data using, for each reading position, a value read through the first color in the first reading and a value read through the second color in the second reading; and a selector that selects one of the first image data or the second image data.