Ricoh Company, Ltd.

Issei Abe

Kazuhiro Fujita

Atsushi Takaura

Tatsuya Takahashi

Hayato Yoshida

Naoki Moniwa

Osamu Nagase

Yoshitsugu Kohno

Akihiro Yamakage

Hiroyuki Satoh

Yasushi Takahashi

Ryosuke Kasahara

Masahiro Itoh

Kiichiro Nishina

Toshiyuki Kawasaki

Jun Kishiwada

Yukiko Hamano

Kento Nakamura

Atsuhsi Takaura

An imaging device includes an imaging element, and an image capturing optical system configured to generate an image of an object on the imaging element. The image capturing optical system has a gradient decreasing region in which a change of a gradient of an image magnification rate with respect to an angle of view of the image generated on the imaging element decreases as a concerned position deviates farther away from an optical axis of the image capturing optical system, and a gradient increasing region in which the change of the gradient of the image magnification rate with respect to the angle of view of the image generated on the imaging element increases as the concerned position deviates farther away from the optical axis of the image capturing optical system.

Imaging device, image capturing optical system, and movable apparatus

A projection optical system is disclosed. The projection optical system includes a first optical system configured to form a first image conjugated with an object and a second optical system configured to project a second image conjugated with the first image toward a projection surface. At least one of the first optical system and second optical system includes at least one optical element(s) movable relative to the object is provided. An image distance of the projection optical system is changed and a size of the second image is changed, by moving at least one of the optical element(s) relative to the object.

Projection optical system and image projecting apparatus

Disclosed is a projection optical system including a first optical system configured to form a first image conjugate to an object and have an optical axis and a second optical system configured to project a second image conjugate to the first image onto a surface to be projected on, wherein the first image satisfies a condition of:&#x2266;1.70wherein Im denotes a length of the first image in a direction of an optical axis of the first optical system, normalized by a focal length of the first optical system, and Tr denotes a throw ratio for the projection optical system.

A lighting device includes a first light source which emits excitation light, a wavelength convertor which generates fluorescence containing at least a first wavelength range and a second wavelength range by excitation with the excitation light, a second light source which emits light containing a third wavelength range different from the first wavelength range and the second wavelength range, an optical path-combining element which combines an optical path for the fluorescence from the wavelength convertor and an optical path for the light from the second light source, so as to guide the combined optical paths to a single emission optical path, and a light separator disposed in the emission optical path, which obtains and emits at least the first wavelength range and the second wavelength range of the fluorescence and at least the third wavelength range of the light from the second light source.

Lighting device, projector including the same, and lighting method

A disclosed projection optical system projects images on a surface to be projected on. The projection optical system includes a first optical system including at least one refraction optical system and having positive power as a whole, a folding mirror, and a second optical system including at least one reflection surface having power and having positive power as a whole. Further the folding mirror folds a light path from the first optical system to the second optical system, and in a plane including an optical axis of the first optical system and a normal line of the surface to be projected on, the following conditional expressions (1) through (3) are satisfied (1) 0.43&#x2266;d, (2) 0.43&#x2266;d, and (3) 0.7&#x2266;d/d&#x2266;2.0.

Projection optical system and image projection device

A wide-angle lens comprising: an imaging lens system, including: a front lens group, an aperture, and a rear lens group, arranged in that order from an object side to an image side; wherein said front lens group comprises first and second lens elements, having negative power respectively, and a third lens that is a positive lens, arranged in that order from the object side to an aperture side; wherein said rear lens group comprises fourth and fifth lens elements, having positive power respectively, arranged in order from the aperture side to the image side; where an incident angle to an optical axis of the imaging lens system of a chief ray of a maximum angle of view passing through the aperture is &#x3b8;I, the following Expression 1 is satisfied.40&#xb0; (degrees)&#x3c;&#x3b8;&#x3c;60&#xb0; (degrees)&#x2003;&#x2003;Expression 1.

Wide-angle lens and imaging apparatus using the same

An image projection apparatus includes: an optical image generating unit to generate an optical image based on image data; a projection surface; a projection optical system including a plurality of optical elements and configured to form an projected image, onto a projection surface, coupled with the optical image generated by the optical image generating unit; a projected image shifting unit to shift the projected image by changing a posture of at least one of the plurality of optical elements included in the projection optical system; a tilt sensor to detect a posture of the optical element of which posture is changed by the projected image shifting unit; and a trapezoidal distortion correction unit to correct the optical image generated by the optical image generating unit so as to prevent the trapezoidal distortion of the projected image from occurring based on the detection result of the tilt sensor.

Image projection apparatus

A projection optical system includes first and second optical systems. The first optical system includes a transmissive-refractive element and the second optical system includes a reflective-refractive element. An image formed by a spatial light modulator is projected by the projection optical system on a projection surface. A light beam that travels along an optical path that leads from the second optical system to the projection surface in an optical path between a center of the image formed by the spatial light modulator and the projection surface is projected at an angle with respect to a normal to the projection surface. An optical axis of the first optical system is folded to a folded position by an optical path deflecting unit in an area of the first optical system where the light beam entering the optical path deflecting unit is a converging light beam or a substantially parallel light beam.

Projection optical system

A projection optical system includes a first optical system, a second optical system, and first and second reflection mirrors. The first and second reflection mirrors are arranged on an optical path between an image forming element and a reflection surface of the second optical system, so that a direction of an optical path of light beams from the second reflection mirror to the reflection surface contains a component of a direction opposite to a predetermined direction from the image forming element to the first optical system, and a projection image of the image forming element on a conjugate surface, a projection of the reflection surface onto the conjugate surface, and a projection of the image forming element onto the conjugate surface are arrayed in this order on the conjugate surface.

A wide angle lens whose field angle exceeds 160 degrees, includes a front group, an aperture stop, and a rear group arranged in this order from an object-side toward an image-side. The front group includes a first lens (negative meniscus) whose convex surface faces the object, a second lens (negative), a third lens (negative), and a fourth lens (positive), arranged in this order from the object-side toward the image-side. The rear group includes a fifth lens (positive), a sixth lens (negative), and a seventh lens (positive), arranged in this order from an aperture-side toward the image-side. The fifth and sixth lenses are combined, forming a cemented lens having positive refractive power. The fifth and sixth lenses are made of materials having Abbe numbers of greater than or equal to 50 and less than or equal to 30, respectively. A surface of the seventh lens facing the image is aspheric.

Wide angle lens and imaging device

A projection optical apparatus capable of providing high image quality and having a reduced size is disclosed. The projection optical apparatus includes a light valve and a projection optical system including a first optical system having a transmissive-refractive element and a second optical system having a reflective-refractive element. An image formed on the light valve is projected by the projection optical system on a projection surface. The optical axis in the first optical system is folded both vertically and horizontally. The first group of the first optical system is contained in a space (dead space) whose lower limit is defined by a lower edge of the second optical system, thereby reducing the depth of the apparatus.

Projection optical apparatus

A projection optical system configured to project an image onto a projection surface includes a first optical system including at least one dioptric system and having positive power as a whole; a second optical system including a reflection region and a transmission region; and a third optical system including at least one reflecting surface having power, and having positive power as a whole, wherein light entering the projection optical system passes through the first optical system to have a path thereof bent by the reflection region of the second optical system to be incident on the third optical system, and the light incident on the third optical system has the path thereof bent by the third optical system to pass through the transmission region of the second optical system to be incident on the projection surface.

Projection optical system and image projector

Disclosed is an image reading device configured to read information of an object, including an imaging optical system configured to image an image of an object and an image-capturing device configured to image-capture at least a portion of the image imaged by the imaging optical system, wherein the imaging optical system includes a first optical system configured to image an intermediate image of the object and a second optical system configured to image the imaged image of the intermediate image.

Image reading device and image forming apparatus

A variable magnification optical system projects an image onto a screen with a sufficient magnification without requiring a large-sized mirror. The variable magnification optical system includes a first optical system through which a light beam modulated with an image signal corresponding to the image is passed; a second optical system disposed downstream of the first optical system in a direction of travel of the light beam along an optical axis; and a reflective optical element having a magnification power that is configured to reflect the light beam from the second optical system toward the screen. A magnification of the image projected on the screen is changed by moving the reflective optical element relative to the object plane, thus changing a distance between the screen and the reflective optical element, while an incident angle of the light beam on the screen is maintained substantially constant.

Variable magnification optical system and projector

A projection optical system, in which a plurality of light flux emitted from one conjugate plane enters another conjugate plane and an image formed on the one conjugate plane is projected on the other conjugate plane, includes: a first optical system including at least one lens; and a second optical system which includes at least two reflecting surfaces with optical power, a normal line of the other conjugate plane from a center of an image projected on the other conjugate plane has no intersection with any space of the first optical system, or the second optical system, or a space between the first optical system and the second optical system, and when a plane defined by a vertical direction of the image projected on the other conjugate plane and an extending direction of the normal line is set as a YZ plane, from the first optical system to the other conjugate plane an optical path intersects only once on the YZ plane.

Growing community of inventors

Kanagawa, Japan

Issei Abe