Abstract: There are provided a small distance measuring device which enables an accurate distance measurement and has a wide range of measurable distances and a projector which is provided with the distance measuring device.

Abstract: A zoom lens system comprising, arranged sequentially from the enlarging side to the reducing side, a first lens group having a negative refractive power as a whole, a second lens group having a positive refractive power as a whole and a third lens group having a positive refractive power as a whole. The third group is fixed during the zooming. The first lens group moves along an optical axis from the enlarging side to the reducing side during zooming from the wide angle end to the intermediate area. The first lens group also moves along the optical axis from the reducing side to the enlarging side during zooming from the intermediate area to the telephoto end. The second lens group moves along the optical axis from the reducing side to the enlarging side during zooming from the wide angle end to the telephoto end. Thus, the zooming operation of the whole lens system is achieved.

Abstract: A high-performance lens system includes lens elements of small diameters for projecting enlarged images from light valves (mainly Digital Micromirror Devices (DMDs))for forming images by changing reflecting directions of light. The lens system includes, sequentially in order from a magnifying side, a first lens group which makes up a substantially afocal optical system as a whole and a second lens group having a positive refractive power as a whole. Depending on the application a third lens group made up of a single positive lens element is provided in the vicinity of the light valve on a contracting side of the second lens group.

Abstract: A zoom lens system comprising, arranged sequentially from the enlarging side to the reducing side, a first lens group having a negative refractive power as a whole, a second lens group having a positive refractive power as a whole and a third lens group having a positive refractive power as a whole. The third group is fixed during the zooming. The first lens group moves along an optical axis from the enlarging side to the reducing side during zooming from the wide angle end to the intermediate area. The first lens group also moves along the optical axis from the reducing side to the enlarging side during zooming from the intermediate area to the telephoto end. The second lens group moves along the optical axis from the reducing side to the enlarging side during zooming from the wide angle end to the telephoto end. Thus, the zooming operation of the whole lens system is achieved.

Abstract: A high-performance lens system includes lens elements of small diameters for projecting enlarged images from light valves (mainly Digital Micromirror Devices (DMDs)) for forming images by changing reflecting directions of light. The lens system includes, sequentially in order from a magnifying side, a first lens group which makes up a substantially afocal optical system as a whole and a second lens group having a positive refractive power as a whole. Depending on the application a third lens group made up of a single positive lens element is provided in the vicinity of the light valve on a contracting side of the second lens group.

Abstract: A high-performance lens system includes lens elements of small diameters for projecting enlarged images from light valves (mainly Digital Micromirror Devices (DMDs)) for forming images by changing reflecting directions of light. The lens system includes, sequentially in order from a magnifying side, a first lens group which makes up a substantially afocal optical system as a whole and a second lens group having a positive refractive power as a whole. Depending on the application a third lens group made up of a single positive lens element is provided in the vicinity of the light valve on a contracting side of the second lens group.

Abstract: To provide a compact, high-performance zoom lens having a small lens aperture for enlarging an image from a light valve such as a DMD for forming an image by changing a reflecting direction of light and projecting the image so enlarged on to a screen or the like, the zoom lens includes, in order from a magnifying side, a first lens group having a negative refractive power as a whole and a second lens group having a positive refractive power as a whole, wherein changing the magnification of a whole lens system thereof is attained by configuring such that while a magnification varying operation is in effect, the first lens group and the second lens group are made to move on the optical axis.

Abstract: A compact zoom lens which projects an image from a DMD on to a screen in an enlarged scale is provided. There is provided a zoom lens including, in order from a magnifying side, a first lens group having a positive or negative refractive power as a whole, a second lens group having a negative refractive power as a whole, a third lens group having a positive or negative refractive power as a whole, a fourth lens group having a positive refractive power as a whole and a fifth lens group having a positive refractive power as a whole, wherein a variable power as a whole lens system of the zoom lens is established by configuring such that the first lens group and the fifth lens group are left fixed, the second lens group, the third lens group and the fourth group are made to move on an optical axis.

Abstract: To provide a high performance compact zoom lens with a small lens aperture which projects an image from a light bulb such as a DMD in which an image is formed by changing reflecting directions of light on to a screen or the like in an enlarged fashion, according to the invention, there is provided zoom lens comprising, in order from a magnifying side thereof, a first lens group having a negative refractive power as a whole, a second lens group having a positive or negative refractive power as a whole and a third lens group having a positive refractive power as a whole, wherein changing the magnification of the whole lens system thereof is attained by configuring such that the first lens group and the second lens group are made to move on an optical axis in such a manner as to move in a direction from a magnifying side to a contracting side over a range from a wide angle end to an intermediate area and to move in a direction from the contracting side to the magnifying side over a range from the intermediate ar

Abstract: To provide a compact, high-performance zoom lens having a small lens aperture for enlarging an image from a light valve such as a DMD for forming an image by changing a reflecting direction of light and projecting the image so enlarged on to a screen or the like, and a zoom lens so provided includes, in order from a magnifying side, a first lens group having a negative refractive power as a whole, a second lens group having a positive refractive power as a whole, and a third lens group having a positive refractive power as a whole, wherein changing the magnification of a whole lens system thereof is attained by configuring such that while a magnification varying operation is in effect, the third lens group is left fixed, the first lens group and the second lens group are made to move on the optical axis.

Abstract: There is provided a compact zoom lens having a small lens aperture which an image from a light valve such as a DMD is projected on to a screen in an enlarged scale. There is provided a zoom lens comprising, in order from a magnifying side, a first lens group having a negative refractive power as a whole, a second lens group having a positive or negative refractive power as a whole, a third lens group having a positive refractive power as a whole and a fourth lens group having a positive refractive power as a whole, wherein a variable power as a whole lens system thereof is established by configuring such that the fourth lens group is left fixed while a variable power is effected, and the first lens group, the second lens group and the third lens group are made to move on the optical axis.

Abstract: There are provided a small distance measuring device which enables an accurate distance measurement and has a wide range of measurable distances and a projector which is provided with the distance measuring device.

Abstract: To provide a high performance compact zoom lens with a small lens aperture which projects an image from a light valve such as a DMD (Digital Micromirror Device) in which an image is formed by changing reflecting directions of light on to a screen or the like in an enlarged fashion, according to the invention, there is provided zoom lens comprising, in order from a magnifying side thereof, a first lens group having a positive or negative refractive power as a whole, a second lens group having a negative refractive power as a whole, a third lens group having a positive or negative refractive power as a whole and a fourth lens group having a positive refractive power as a whole, wherein changing the magnification of the whole lens system thereof is attained by configuring such that the first lens group is left fixed while a magnification varying operation is effect, the second lens group, the third lens group and the fourth lens group are made to move on an optical axis.

Abstract: To provide a compact, high-performance zoom lens having a small lens aperture for enlarging an image from a light valve such as a DMD for forming an image by changing a reflecting direction of light and projecting the image so enlarged on to a screen or the like, the zoom lens includes, in order from a magnifying side, a first lens group having a positive or negative refractive power as a whole, a second lens group having a negative refractive power as a whole and a third lens group having a positive refractive power as a whole, wherein changing the magnification of a whole lens system thereof is attained by configuring such that while a magnification varying operation is in effect, the first lens group is left fixed, and the second lens group and the third lens group are made to move on the optical axis.

Abstract: A high-performance lens system including lens elements of small diameters for projecting on to a screen or the like in an enlarged fashion images from light valves such as mainly DMDs (Digital Micromirror Devices) for forming images by changing reflecting directions of light is provided. A lens system includes, sequentially in that order from a magnifying side, a first lens group which makes up a substantially afocal optical system as a whole and a second lens group having a positive refractive power as a whole, the second lens group being configured to include, sequentially in that order from a magnifying side thereof, a first sub-lens group or 2a lens group having a negative refractive power as a whole and a second sub-lens group or 2b lens group having a positive refractive power as a whole, and depending upon applications, a third lens group made up of a single positive lens element is provided in the vicinity of a light valve such as a DMD on a contracting side of the second lens group.

Abstract: A high-performance lens system including lens elements of small diameters for projecting on to a screen or the like in an enlarged fashion images from light valves such as mainly DMDs (Digital Micromirror Devices) for forming images by changing reflecting directions of light is provided. A lens system includes, sequentially in that order from a magnifying side, a first lens group which makes up a substantially afocal optical system as a whole and a second lens group having a positive refractive power as a whole, and depending upon applications, a third lens group made up of a single positive lens element is provided in the vicinity of a light valve such as a DMD on a contracting side of the second lens group.

Abstract: In a thin projector for projecting an image from a light valve such as a DMD, a compact zoom lens comprises, in order, a first lens group having a negative refractive power, a second lens group having a positive refractive power, a third lens-group having a negative refractive power, and a fourth lens group having a positive refractive power. The fourth lens group is fixed while the focal length is being changed. The first and second lens group are movable on an optical axis in a direction from the enlarging side towards the reducing side over a range from a wide angle end to an intermediate range, and are movable on the optical axis in a direction from the reducing side towards the enlarging side over a range from the intermediate range to a telephoto end. The third lens group moves on the optical axis in a direction from the reducing side to the enlarging side over a range from the wide angle end to the telephoto end, whereby the focal length of the whole lens system of the zoom lens is changed.

Abstract: A zoom lens includes a first lens group having positive or negative refractive power, a second lens group having negative refractive power, a third lens group having positive refractive power, and a fourth lens group having positive refractive power. A variable power is set such that the first and fourth lens group are left fixed, the second lens group is made to move from a magnifying side to a contracting side over a range from a wide angle end to an intermediate area and is made to move on an optical axis from the contracting side to the magnifying side over a range from the intermediate area to a telephoto end, and the third lens group is made to move on the optical axis from the contracting side to the magnifying side over a range from the wide angle end to the telephoto end.

Abstract: A high-performance lens system including lens elements of small diameters for projecting on to a screen or the like in an enlarged fashion images from light valves such as mainly DMDs (Digital Micromirror Devices) for forming images by changing reflecting directions of light is provided. A lens system includes, sequentially in that order from a magnifying side, a first lens group which makes up a substantially afocal optical system as a whole and a second lens group having a positive refractive power as a whole, the second lens group being configured to include, sequentially in that order from a magnifying side thereof, a first sub-lens group or 2a lens group having a negative refractive power as a whole and a second sub-lens group or 2b lens group having a positive refractive power as a whole, and depending upon applications, a third lens group made up of a single positive lens element is provided in the vicinity of a light valve such as a DMD on a contracting side of the second lens group.

Abstract: A high-performance lens system including lens elements of small diameters for projecting on to a screen or the like in an enlarged fashion images from light valves such as mainly DMDs (Digital Micromirror Devices) for forming images by changing reflecting directions of light is provided. A lens system includes, sequentially in that order from a magnifying side, a first lens group which makes up a substantially afocal optical system as a whole and a second lens group having a positive refractive power as a whole, and depending upon applications, a third lens group made up of a single positive lens element is provided in the vicinity of a light valve such as a DMD on a contracting side of the second lens group.