Seiko Epson Corporation

Nobutaka Minefuji

Eiji Morikuni

Koji Shiokawa

Masayuki Okoshi

Satoru Nagarekawa

Hitoshi Hirano

Naoto Takehana

Yasuyuki Kiyama

A projection system includes a first optical system and a second optical system disposed on an enlargement side of the first optical system. The first optical system includes a first lens group having positive power, a second lens group disposed on the enlargement side of the first lens group and having negative power, and an optical path deflector disposed between the first lens group and the second lens group. The second optical system includes a reflection member having a concave reflection surface. The second lens group includes three aspherical lenses. Conditional Expression (1) below is satisfied,0.25<|max<0.5  (1)where F represents the focal length of the entirety of the projection system, FNO represents the F number of the projection system, and Ymax represents a maximum image height in a reduction-side conjugate plane.

Projection system and projector

A projection system includes a first optical system and a second optical system. The second optical system includes a first lens group disposed on an enlargement side of an intersection position where a chief ray of an off-axis beam having a maximum angle of view intersects with an optical axis of the projection system in the second optical system, a second lens group disposed on the reduction side of the intersection position and having negative power, and a third lens group disposed on the reduction side of the second lens group and having positive power. The second lens group includes a first lens having positive power, a second lens disposed on the reduction side of the first lens and having positive power, and a third lens disposed on the reduction side of the second lens and having negative power. The third lens group includes two lenses each having positive power.

Projection system and projector with first optical system and second optical system

A projection optical system includes a first lens group having negative power, a second lens group having positive power and disposed at a reduction side of the first lens group, and a third lens group having positive power and disposed at the reduction side of the second lens group. The first lens group includes at least three negative lenses. The second lens group includes at least one positive lens. The third lens group includes a plurality of positive lenses. The at least three negative lenses of the first lens group are each a single lens. The third lens group includes a jointed lens including at least one of the plurality of positive lenses. NA is a reduction-side numerical aperture, Dst is a distortion aberration at a reduction-side maximum image height, and the projection optical system satisfies Conditional Expressions (1) and (2),0.2&#x3c;NA&#x2003;&#x2003;(1)&#x2212;45%&#x3c;Dst&#x3c;&#x2212;10%&#x2003;&#x2003;(2).

Projection optical system and projector

A projection optical system includes a first lens group having negative power and a second and third lens group having positive power, and a first optical path deflector disposed between two lens groups. The first lens group includes three negative lenses. The second lens group includes at least one positive lens. The third lens group includes a plurality of positive lenses. The three negative lenses of the first lens group are each a single lens. The third lens group includes a jointed lens including at least one of the plurality of positive lenses. f is a focal length of the entire project in optical system, d is a length between two lens groups where the first optical path defector is disposed, Dst is a distortion aberration at a reduction-side maximum image height, and the projection optical system satisfies Conditional Expressions (1) and (2) below:0.4&#x3c;&#x3c;12.0&#x2003;&#x2003;(1)&#x2212;45%&#x3c;&#x3c;&#x2212;10%&#x2003;&#x2003;(2).

A first optical group that forms an intermediate image and a second optical group that enlarges and projects the intermediate image formed by the first optical group satisfy a variety of conditions. Therefore, the overall length of the entire lens system of the projection system is reduced in a linear arrangement, or the distance between the first optical group and the second optical group is increased and an optical path deflector that deflects the optical path is disposed at the middle of the optical path between the first and second optical groups to fold the optical path.

Projection system and projection-type image display apparatus

A first optical group that forms an intermediate image and a second optical group that enlarges and projects the intermediate image formed by the first optical group satisfy a variety of conditions. Therefore, first of all, in a case where a projection system is incorporated in a projector, an ultrawide field angle that allows enlargement and projection of an image at a half angle of view of 50&#xb0; or greater is achieved. Further, an optical path deflection system including two optical path deflectors is disposed between the first optical group and the second optical group to allow the optical path to be folded with deterioration in performance of the projection system suppressed.

A projection optical system includes a first lens unit adapted to make a enlargement-side imaging surface and an intermediate image conjugate with each other, a second lens unit adapted to make the intermediate image and a reduction-side imaging surface conjugate with each other. The first lens unit has positive power, and the second lens unit has negative power. Defining a focal distance of the first lens unit as fU, a focal distance of the second lens unit as fU, a total lens length of the first lens unit as LLU, and a total lens length of the second lens unit as LLU, the following expression (1) and expression (2) are satisfied:&#x2212;0.3&#x3c;1/2&#x3c;&#x2212;0.005&#x2003;&#x2003;(1)0.5&#x3c;1/2&#x3c;0.9&#x2003;&#x2003;(2).

Projection optical system and projection image display device

A projection optical system and that includes a relatively small number of lenses and are able to cover a wide zooming range and a projector. A 1-2 lens group which is a focus lens group is constituted with a lens which includes a single positive lens having a convex surface to the reduction side, a lens which includes a single negative meniscus lens having a convex surface to an enlargement side, and a lens which includes a single negative lens, and the 1-2 lens group is moved at the time of focusing accompanying magnification change.

A projection optical system capable of performing compact and proximate projection and a projector including the projection optical system. The projection optical system includes a first optical group which is a dioptric system and a second optical group which is a catoptric system. The second optical group includes a first catoptric system to a third catoptric system that have a first reflection surface with a concave surface shape, a second reflection surface with a curved surface shape, and a third reflection surface with a convex surface shape. The first catoptric system to the third catoptric system satisfy Conditional Expression (1) for focal distances. Image light emitted from the first optical group is reflected by the second optical group to be projected to a projection surface.

An imaging lens system (imaging lens) having a focal length f is formed of a first lens group formed of three negative lenses and a single positive lens or a cemented lens and a second lens group having a positive focal length with the first lens group and the second lens group sequentially arranged from the enlargement side and employs the stereographic projection method that satisfies a condition of y=a&#xb7;f&#xb7;tan(&#x3b8;/2) (&#x3b1;: 1.8&#x2264;&#x3b1;&#x2264;2.2). The thus configured imaging lens system readily allows distortion to be reduced at each image height y and the degree of compression to be also reduced for sufficient resolution at the periphery.

Imaging lens system, imaging apparatus and projector

First through third lens groups constituting a projection zoom lens can be configured as a zoom lens of the type in which the first and second lens groups, for example, are moved when zooming, and the first lens group, for example, is moved when focusing. Further, by fulfilling the conditional formula (1), it is possible to achieve that the back focus is prevented from becoming too short, and the back focus is prevented from becoming too long while ensuring the sufficient space on the reduction side, and the lens diameter on the reduction side is prevented from becoming too large in the case of adopting a roughly telecentric configuration on the reduction side.

Projection zoom lens and projection type image display device

A projector used a projection lens to enlarge and project image light generated by image generator. When it is assumed that the on-optical-axis position of a lens surface where the maximum of light ray passage ranges (effective diameter) is minimized in the projection lens is a minimum diameter position, a stop is provided on a lens shifted from the minimum diameter position toward the light exiting side. The lens on which the stop is provided is a lens (for example, fourth lens closest to minimum diameter position) that satisfies 0.8&#x3c6;&#x2266;&#x3c6;&#x2266;&#x3c6;, where &#x3c6;represents the light flux diameter on a surface where the on-axis light flux diameter is maximized, and &#x3c6;is the diameter of the stop.

Projection lens and projector

The 1-2nd lens group is divided into three lens groups which move when focusing is performed during the magnification change. Even in a case in which the second optical group is formed of one mirror, it is possible for a primary image to contain appropriate aberration and to hereby reduce aberration of an image which is finally projected onto a screen through the second optical group.

Projection optical system

To provide a projection optical system that can cover a wide range of magnification changes with a focus lens group in which the number of constituted lenses is decreased, and a projector including the projection optical system. A 1-2nd lens group as the focus lens group includes an Flens group configured of one positive lens, an Flens group configured of one positive lens and one negative lens, and an Flens group configured of one negative lens. At least the Flens group is caused to move when focusing is performed in response to a magnification change.

In a 1-2nd lens group, an aspherical resin lens is disposed on the outermost enlargement side, an enlargement-side fixed lens group (second fixed lens group) as a fixed group is disposed, a moving lens group, which move when focusing is performed in response to the magnification change, is disposed further on the reduction side from the second fixed lens group. Even in a case where the second optical group is configured of one mirror, it is possible for a primary image to have appropriate aberration and to hereby reduce aberration of an image which is finally projected onto a screen through the second optical group.

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Azumino, Japan

Nobutaka Minefuji