Abstract: There is provided is a spectrometer having a concave reflection type diffraction element, wherein, among surfaces other than a diffraction surface of the diffraction element, non-diffraction surfaces which are located outside the diffraction surface at the same side as the diffraction surface are a glossy surface, the spectrometer includes a light detection unit which is located at an imaging position of a first-order diffracted light diffracted by the diffraction element to receive the first-order diffracted light, and the light detection unit is disposed inside optical paths of light beams regularly reflected on the non-diffraction surfaces outside the diffraction surface. Accordingly, it is possible to effectively suppress a stray light reflected on the surfaces other the diffraction surface from being incident into the light detection unit and to detect the light spectrally diffracted by the diffraction surface at high accuracy.

Abstract: An image reading apparatus sets an irradiation region below a fixed reading glass when light guide members diffuse light of LEDs upward so that the irradiation region corresponding to a significantly sagged portion in a main scanning direction is wider than that corresponding to portions on both sides of the significantly sagged portion, and sets a light intensity of a plurality of LEDs corresponding to the significantly sagged portion in the main scanning direction to be larger than that of a plurality of LEDs corresponding to the portions on both sides of the significantly sagged portion. Therefore, the degradation of the illuminance corresponding to the significantly sagged portion due to the pressed fixed reading glass can be prevented, and the entire document can be read with uniform reading precision.

Abstract: An image reading apparatus sets an irradiation region below a fixed reading glass when light guide members diffuse light of LEDs upward so that the irradiation region corresponding to a significantly sagged portion in a main scanning direction is wider than that corresponding to portions on both sides of the significantly sagged portion, and sets a light intensity of a plurality of LEDs corresponding to the significantly sagged portion in the main scanning direction to be larger than that of a plurality of LEDs corresponding to the portions on both sides of the significantly sagged portion. Therefore, the degradation of the illuminance corresponding to the significantly sagged portion due to the pressed fixed reading glass can be prevented, and the entire document can be read with uniform reading precision.

Abstract: A spectral colorimetric apparatus for detecting a color of an image of a subject, including: an illumination optical system illuminating the subject on a detection surface; a spectral optical system including a spectral element spectrally separating the beam diffused by the subject and a light receiving element array detecting a spectral intensity distribution; and a guiding optical system for guiding a beam diffused by the subject, wherein: the detection surface is parallel to a spectral plane including a principal ray of a beam entering the spectral optical system and a principal ray of a beam spectrally separated; the principal ray of the beam enters the spectral optical system within the spectral plane obliquely to a line joining a center of the light receiving element array with a surface vertex of the spectral element; and a light receiving surface of the light receiving element array is orthogonal to the spectral plane.

Abstract: A spectral colorimetric apparatus for detecting a color of an image of a subject, including: an illumination optical system illuminating the subject on a detection surface; a spectral optical system including a spectral element spectrally separating the beam diffused by the subject and a light receiving element array detecting a spectral intensity distribution; and a guiding optical system for guiding a beam diffused by the subject, wherein: the detection surface is parallel to a spectral plane including a principal ray of a beam entering the spectral optical system and a principal ray of a beam spectrally separated; the principal ray of the beam enters the spectral optical system within the spectral plane obliquely to a line joining a center of the light receiving element array with a surface vertex of the spectral element; and a light receiving surface of the light receiving element array is orthogonal to the spectral plane.

Abstract: A spectral colorimetric apparatus for detecting a color of an image of a subject, including: an illumination optical system illuminating the subject on a detection surface; a spectral optical system including a spectral element spectrally separating the beam diffused by the subject and a light receiving element array detecting a spectral intensity distribution; and a guiding optical system for guiding a beam diffused by the subject, wherein: the detection surface is parallel to a spectral plane including a principal ray of a beam entering the spectral optical system and a principal ray of a beam spectrally separated; the principal ray of the beam enters the spectral optical system within the spectral plane obliquely to a line joining a center of the light receiving element array with a surface vertex of the spectral element; and a light receiving surface of the light receiving element array is orthogonal to the spectral plane.

Abstract: Provided is an illuminator including a light source unit having a light emitting surface, and a light guiding member guiding a light beam to an original disposed on an original plate. An intersection of a center axis of a light emitting surface and the original plate is separated from a reading position of the original in a sub scanning direction, the light guiding member includes an incident surface to which the light beam emitted from the light source unit is incident, a reflection surface that reflects the incident light beam, and an exiting surface exiting the incident light beam and the reflected light beam, and in the sub scanning section, the light beam having the highest light intensity in the light beams from the light source unit is deflected at the incident surface toward the reading position of the original with respect to the center axis.

Abstract: There is provided is a spectrometer having a concave reflection type diffraction element, wherein, among surfaces other than a diffraction surface of the diffraction element, non-diffraction surfaces which are located outside the diffraction surface at the same side as the diffraction surface are a glossy surface, the spectrometer includes a light detection unit which is located at an imaging position of a first-order diffracted light diffracted by the diffraction element to receive the first-order diffracted light, and the light detection unit is disposed inside optical paths of light beams regularly reflected on the non-diffraction surfaces outside the diffraction surface. Accordingly, it is possible to effectively suppress a stray light reflected on the surfaces other the diffraction surface from being incident into the light detection unit and to detect the light spectrally diffracted by the diffraction surface at high accuracy.

Abstract: A spectral colorimetric apparatus for detecting a color of an image of a test subject illuminated includes a stop; a spectral detection optical system for spectrally detecting a beam diffused in the test subject and passing through the stop; and a guiding optical system for guiding, toward the stop, the beam diffused in the test subject, wherein in a first section which is a section including an optical axis of the guiding optical system, condensing positions of the light beam condensed by the guiding optical system change depending on a position in a direction orthogonal to the first section, and the stop is disposed between condensing positions closest to and farthest from the guiding optical system, of condensing positions, in the first section, of the beam condensed by the guiding optical system, in a direction of the optical axis of the guiding optical system.

Abstract: An object is to provide an imaging optical system having a very simple structure that can read image while maintaining excellent image quality without suffering from significant asymmetrical aberrations. An imaging optical system for image reading is adapted to form an image of image information on a surface of an original onto a line sensor while changing a relative position of the original surface and the line sensor to allow the line sensor to read the image information. The imaging optical system includes two off-axial reflecting surfaces, and the two off-axial surfaces are a plus deflecting surface and a minus deflecting surface, or a minus deflecting surface and a plus deflecting surface disposed in the mentioned order from the original surface side, where an off-axial reflecting surface that deflects a reference axis beam clockwise is defined as a minus deflecting surfaces and an off axial reflecting surface that deflects the reference axis beam anticlockwise is defined as a plus deflecting surface.

Abstract: A spectral colorimetric apparatus for detecting a color of an image of a test subject illuminated includes a stop; a spectral detection optical system for spectrally detecting a beam diffused in the test subject and passing through the stop; and a guiding optical system for guiding, toward the stop, the beam diffused in the test subject, wherein in a first section which is a section including an optical axis of the guiding optical system, condensing positions of the light beam condensed by the guiding optical system change depending on a position in a direction orthogonal to the first section, and the stop is disposed between condensing positions closest to and farthest from the guiding optical system, of condensing positions, in the first section, of the beam condensed by the guiding optical system, in a direction of the optical axis of the guiding optical system.

Abstract: A spectral colorimetric apparatus for detecting a color of an image of a subject, including: an illumination optical system illuminating the subject on a detection surface; a spectral optical system including a spectral element spectrally separating the beam diffused by the subject and a light receiving element array detecting a spectral intensity distribution; and a guiding optical system for guiding a beam diffused by the subject, wherein: the detection surface is parallel to a spectral plane including a principal ray of a beam entering the spectral optical system and a principal ray of a beam spectrally separated; the principal ray of the beam enters the spectral optical system within the spectral plane obliquely to a line joining a center of the light receiving element array with a surface vertex of the spectral element; and a light receiving surface of the light receiving element array is orthogonal to the spectral plane.

Abstract: Provided is an illuminator including a light source unit having a light emitting surface, and a light guiding member guiding a light beam to an original disposed on an original plate. An intersection of a center axis of a light emitting surface and the original plate is separated from a reading position of the original in a sub scanning direction, the light guiding member includes an incident surface to which the light beam emitted from the light source unit is incident, a reflection surface that reflects the incident light beam, and an exiting surface exiting the incident light beam and the reflected light beam, and in the sub scanning section, the light beam having the highest light intensity in the light beams from the light source unit is deflected at the incident surface toward the reading position of the original with respect to the center axis.

Abstract: There is provided is a spectrometer having a concave reflection type diffraction element, wherein, among surfaces other than a diffraction surface of the diffraction element, non-diffraction surfaces which are located outside the diffraction surface at the same side as the diffraction surface are a glossy surface, the spectrometer includes a light detection unit which is located at an imaging position of a first-order diffracted light diffracted by the diffraction element to receive the first-order diffracted light, and the light detection unit is disposed inside optical paths of light beams regularly reflected on the non-diffraction surfaces outside the diffraction surface. Accordingly, it is possible to effectively suppress a stray light reflected on the surfaces other the diffraction surface from being incident into the light detection unit and to detect the light spectrally diffracted by the diffraction surface at high accuracy.

Abstract: An object is to provide an imaging optical system having a very simple structure that can read image while maintaining excellent image quality without suffering from significant asymmetrical aberrations. An imaging optical system for image reading is adapted to form an image of image information on a surface of an original onto a line sensor while changing a relative position of the original surface and the line sensor to allow the line sensor to read the image information. The imaging optical system includes two off-axial reflecting surfaces, and the two off-axial surfaces are a plus deflecting surface and a minus deflecting surface, or a minus deflecting surface and a plus deflecting surface disposed in the mentioned order from the original surface side, where an off-axial reflecting surface that deflects a reference axis beam clockwise is defined as a minus deflecting surfaces and an off axial reflecting surface that deflects the reference axis beam anticlockwise is defined as a plus deflecting surface.

Abstract: An object is to provide an imaging optical system having a very simple structure that can read image while maintaining excellent image quality without suffering from significant asymmetrical aberrations. An imaging optical system for image reading is adapted to form an image of image information on a surface of an original onto a line sensor while changing a relative position of the original surface and the line sensor to allow the line sensor to read the image information. The imaging optical system includes two off-axial reflecting surfaces, and the two off-axial surfaces are a plus deflecting surface and a minus deflecting surface, or a minus deflecting surface and a plus deflecting surface disposed in the mentioned order from the original surface side, where an off-axial reflecting surface that deflects a reference axis beam clockwise is defined as a minus deflecting surfaces and an off-axial reflecting surface that deflects the reference axis beam anticlockwise is defined as a plus deflecting surface.

Abstract: Obtained are an imaging optical system having a simple structure in which imaging position deviation due to deformation caused by a weight of an off-axial optical element is reduced and an image reading apparatus using the same. According to an imaging optical system for image reading, image information on an original surface is imaged on a sensor, and is read by the sensor. The imaging optical system includes reflection-type off-axial optical elements, each of which has an outer shape whose lengths in directions orthogonal to each other are different from each other and whose thickness is smaller than a length of the outer shape in a short-direction thereof and is made of a resin material. The plurality of off-axial optical elements are disposed such that mirror surfaces thereof are opposed to each other and constructed to satisfy a conditional expression.

Abstract: Obtained are an imaging optical system having a simple structure in which imaging position deviation due to deformation caused by a weight of an off-axial optical element is reduced and an image reading apparatus using the same. According to an imaging optical system for image reading, image information on an original surface is imaged on a sensor, and is read by the sensor. The imaging optical system includes reflection-type off-axial optical elements, each of which has an outer shape whose lengths in directions orthogonal to each other are different from each other and whose thickness is smaller than a length of the outer shape in a short-direction thereof and is made of a resin material. The plurality of off-axial optical elements are disposed such that mirror surfaces thereof are opposed to each other and constructed to satisfy a conditional expression.

Abstract: To provide a compact imaging optical system in which occurrence of an asymmetrical aberration is reduced and the optical performance is not deteriorated significantly by constituting the system by off-axial reflection surfaces, and an image reading apparatus using the same. The imaging optical system of the present invention is characterized in that, in the imaging optical system for imaging image information of an object surface on a line sensor, all of a plurality of reflection surfaces existing in an optical path from the original surface to the line sensor are off-axial reflecting surfaces.

Abstract: Obtained are an imaging optical system having a simple structure in which imaging position deviation due to deformation caused by a weight of an off-axial optical element is reduced and an image reading apparatus using the same. According to an imaging optical system for image reading, image information on an original surface is imaged on a sensor, and is read by the sensor. The imaging optical system includes reflection-type off-axial optical elements, each of which has an outer shape whose lengths in directions orthogonal to each other are different from each other and whose thickness is smaller than a length of the outer shape in a short-direction thereof and is made of a resin material. The plurality of off-axial optical elements are disposed such that mirror surfaces thereof are opposed to each other and constructed to satisfy a conditional expression.