Patent application number | Description | Published |
20140160217 | OPTICAL SCANNING APPARATUS, IMAGE FORMING APPARATUS, AND SUPPORT MEMBER FOR AN OPTICAL SCANNING APPARATUS - Provided is an optical scanning apparatus, including: an optical deflector having a polygon mirror reflecting a light flux emitted from a light source to carry out scanning, a drive unit rotating the polygon mirror about a rotation shaft, and a board supporting the drive unit; an optical box to which the board is fixed; two holes provided in the optical box, through which two screws fixing the board are inserted, respectively; two bearing surfaces provided on the optical box at positions around the two holes, respectively, the two bearing surfaces supporting the board; and an abutment portion provided on the optical box and abutting against a portion that is prevented from being pressed by the two screws in the board which is sandwiched between the two screws and the two bearing surfaces so as to be fixed to the optical box. | 06-12-2014 |
20140292996 | IMAGE FORMING APPARATUS FOR DETERMINING A TIME TO START FORMING AN IMAGE - The image forming apparatus includes a determination unit configured to determine whether or not a polygon mirror has converged to the number of rotations that allows image formation to be performed, and the determination unit is capable of detecting a first timing and a second timing and determines that the polygon mirror has converged to a number of rotations that allows the image formation to be performed based on an earlier one of the first timing and the second timing. | 10-02-2014 |
20150055967 | IMAGE FORMING APPARATUS FOR DETERMINING A TIME TO START FORMING AN IMAGE - The image forming apparatus includes a determination unit configured to determine whether or not a polygon mirror has converged to the number of rotations that allows image formation to be performed, and the determination unit is capable of detecting a first timing and a second timing and determines that the polygon mirror has converged to a number of rotations that allows the image formation to be performed based on an earlier one of the first timing and the second timing. | 02-26-2015 |
Patent application number | Description | Published |
20140111868 | VARIABLE-MAGNIFICATION PROJECTION OPTICAL SYSTEM AND PROJECTION DISPLAY DEVICE - A variable-magnification projection optical system substantially consists of a negative first lens group that is disposed at the most enlargement-side position and is fixed during magnification change, a positive last lens group that is disposed at the most reduction-side position and is fixed during magnification change, and a plurality of lens groups that are disposed between the first lens group and last lens group and are moved during magnification change. The lens groups that are moved during magnification change substantially consist of three lens groups, wherein the most enlargement-side lens group is a negative lens group. Predetermined conditional expressions relating to a back focus of the entire system on the reduction side at the wide-angle end, a focal length of the entire system at the wide-angle end, a focal length of the last lens group, and a focal length of the first lens group are satisfied. | 04-24-2014 |
20140126067 | VARIABLE-MAGNIFICATION PROJECTION OPTICAL SYSTEM AND PROJECTION DISPLAY DEVICE - A variable-magnification projection optical system substantially consists of a negative first lens group that is disposed at the most enlargement-side position and is fixed during magnification change, a positive last lens group that is disposed at the most reduction-side position and is fixed during magnification change, and a plurality of lens groups that are disposed between the first lens group and last lens group and are moved during magnification change. The most enlargement-side lens group (the second lens group) of the lens groups that are moved during magnification change has a negative refractive power. Predetermined conditional expressions relating to a back focus of the entire system on the reduction side at the wide-angle end, a focal length of the entire system at the wide-angle end, a focal length of the second lens group and a focal length of the last lens group are satisfied. | 05-08-2014 |
20140307327 | PROJECTION LENS AND PROJECTION DISPLAY APPARATUS - A projection lens that projects image information displayed on the reduction side conjugate position onto the magnification side conjugate position includes an aspherical lens having a positive refractive power that satisfies predetermined conditional expressions and, when the back focus of the entire system is taken as Bf, the focal length of the entire system is taken as f, the maximum effective image circle diameter on the reduction side is taken as Imφ, and the distance from the reduction side conjugate position to the reduction side pupil position is taken as dexp, satisfies conditional expressions (6): Bf/f>2 and (7): 0.5<|Imφ/dexp|<1. | 10-16-2014 |
20140347740 | OPTICAL SYSTEM FOR PROJECTION AND PROJECTION-TYPE DISPLAY APPARATUS - In an optical system for projection that is telecentric on a reduction side, a correction lens group substantially consisting of a part of lens groups in the optical system for projection is configured to move in the direction of an optical axis to correct a shift in a focal position caused by a change in temperature, and predetermined conditional formulas are satisfied. | 11-27-2014 |
20150036228 | LENS FOR PROJECTION AND PROJECTION-TYPE DISPLAY APPARATUS - A lens for projection substantially consists of a negative first lens group, a positive second lens group and a positive third lens group in this order from a magnification side. A reduction side is telecentric, and a most magnification-side lens is an aspheric plastic lens. The third lens group consists of a negative front group and a positive rear group in this order from the magnification side with an air space therebetween. The front group consists of a negative lens and a positive lens in this order from the magnification side with an air space therebetween, and the air space being narrower than the air space between the front group and the rear group. Conditional formula (1): −0.702-05-2015 | |
20150085375 | VARIABLE MAGNIFICATION OPTICAL SYSTEM FOR PROJECTION AND PROJECTION-TYPE DISPLAY APPARATUS - A variable magnification optical system for projection consists of a negative lens group and a positive lens group in this order from a magnification side. A distance on an optical axis between the negative lens group and the positive lens group changes during magnification change, and an entire system substantially consists of six lenses. The negative lens group consists of a first lens including an aspheric surface and a second lens that is a negative single lens in this order from the magnification side. | 03-26-2015 |
Patent application number | Description | Published |
20090109543 | PROJECTION LENS AND PROJECTION TYPE DISPLAY DEVICE USING THE SAME - A projection lens includes, in order form a magnification side: a first lens group having negative refractive power; and a second lens group having positive refractive power. An aspheric lens is arranged on the most magnification side of the first lens group. The conditional expressions 304-30-2009 | |
20090262437 | PROJECTION ZOOM LENS SYSTEM AND PROJECTION TYPE DISPLAY APPARATUS - A projection zoom lens includes a first lens group having a negative reflecting power and a second to fifth lens groups each having a positive reflecting power are provided in the order from the magnification side. Nine lenses are distributed in a manner that the first lens group has one lens, the second lens group has one lens, the third lens group has two lenses, the fourth lens group has four lenses and the fifth lens group has one lens. Since the second lens group, the third lens group and the fourth lens group are moved at the time of the power-varying operation, various kinds of aberrations may be made despite of simple configuration. The first lens group is an aspherical lens which concave surface is directed to the reduction side. | 10-22-2009 |
20100142060 | PROJECTION ZOOM LENS SYSTEM AND PROJECTION TYPE DISPLAY APPARATUS - In order from a magnification side of the projection zoom lens system, five lens groups are arranged. The fourth lens group includes, in order from the magnification side, a negative lens having at least one aspheric surface, a positive lens, a negative lens concave toward the magnification side, a positive lens convex toward the reduction side, and a positive lens. The fifth lens group is formed of one lens, and is configured so that a ratio of a focal length of the fifth lens group to a focal length of the whole system at a wide-angle end is within a numerical range of 3 to 8. | 06-10-2010 |
20110026111 | PROJECTION OPTICAL SYSTEM AND PROJECTION DISPLAY DEVICE USING THE SAME - Disclosed are a projection optical system that has a sufficiently small size to be provided in a front-projection-type projector and can effectively correct various aberrations and a projection display device using the same. | 02-03-2011 |
20110157716 | ZOOM LENS FOR PROJECTION AND PROJECTION-TYPE DISPLAY APPARATUS - A zoom lens for projection includes a first negative lens group, a second positive lens group, a third positive lens group, a fourth lens group, and a fifth positive lens group, which are sequentially arranged from the magnification side of the zoom lens. The first lens group and the fifth lens group are fixed, and the second lens group, the third lens group and the fourth lens group move along the optical axis of the zoom lens when magnification of the zoom lens is changed. Each of the first lens group and the second lens group is composed of two lenses. Each of the third lens group and the fifth lens group is composed of a positive lens, and the fourth lens group is composed of five lenses. Further, the reduction side of the zoom lens is telecentric. | 06-30-2011 |
20110249344 | VARIABLE MAGNIFICATION OPTICAL SYSTEM FOR PROJECTION AND PROJECTION-TYPE DISPLAY APPARATUS - A variable magnification optical system for projection includes a first-lens-group having negative refractive power, and which is fixed when magnification of the variable magnification optical system is changed, a second-lens-group having negative refractive power, and which is movable when magnification of the variable magnification optical system is changed, a third-lens-group having positive refractive power, and which is movable when magnification of the variable magnification optical system is changed, and a fourth-lens-group having positive refractive power, and which is fixed when magnification of the variable magnification optical system is changed, which are arranged from the magnification side of the variable magnification optical system in the order mentioned above. The reduction side of the variable magnification optical system is telecentric, and formula (11) is satisfied: | 10-13-2011 |