JP3472508B2 - Projection lens, image enlargement projection system using the same, video projector, rear projector, and multi-vision system - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection lens, and more particularly to a projection lens for a projector for enlarging and projecting an image of a spatial light modulator on a screen and a projector using the same.

[0002]

2. Description of the Related Art As a method of obtaining a large screen image, there is a method of forming an optical image according to an image signal on a spatial light modulator, irradiating the optical image with light, and enlarging and projecting it on a screen by a projection lens. Are known. Recently, a projector using a liquid crystal panel as a spatial light modulator has been receiving attention. If a reflective liquid crystal panel is used as the spatial modulation element, the illumination light from the light source can be guided to the projection lens more effectively.

As a method of obtaining a color image, R, G,
A method of combining the images of the three liquid crystal panels using a dichroic prism by using three liquid crystal panels corresponding to the image signals of each color of B, and the light from the light source is temporally R, G, B It is known how to divide into.

[0004]

A projector using a prism requires a projection lens having a long back focus because a large space is required between the lens and the spatial modulation element.

Further, in a projector using a prism, since the incident angle largely depends on the prism, a light ray incident at an angle other than the designed incident angle has a change in transmittance, resulting in uneven color on the screen. Brightness unevenness occurs. Therefore, the projection lens is required to have telecentricity.

In a projector for data display or graphic display in which performance around the screen is strictly required, it is important that there is no graphic distortion or color bleeding. Therefore, distortion of the projection lens and chromatic aberration of magnification occur. It must be well corrected.

In addition, these projectors are required to have brightness around the screen, and a peripheral light amount ratio of 70% or more is required.

Japanese Unexamined Patent Publication No. 2-228620 discloses a projection lens in which back focus, telecentricity and distortion are corrected, but it has the following problems. That is, there is a problem that the half field angle is as small as 36 ° and the set size becomes too large for use as a projection television.

The present invention has been made in order to solve the above problems in the prior art, and by appropriately setting the lens configuration, the half angle of view is as large as 40 ° or more, and the back focus is long. Bright to the periphery of the screen,
An object of the present invention is to provide a projection lens capable of sufficiently correcting distortion and chromatic aberration of magnification and obtaining a high-quality image over the entire screen, and a projector using the projection lens.

[0010]

To achieve the above object, a projection lens according to a first aspect of the present invention has a first lens group arranged in order from the screen side and a second lens group having a positive power. A projection lens including a group, wherein the I-th lens group is arranged in order from the screen side,
A positive meniscus lens having a convex surface facing the screen side, a first negative meniscus lens having a convex surface facing the screen side, a second negative meniscus lens having a convex surface facing the screen side, and a surface having a small radius of curvature facing the screen side. A biconcave lens directed toward, a biconvex lens, and a biconvex lens. The second lens group includes a cemented concave lens and at least two convex lenses arranged in order from the screen side. An aperture is provided in the lens group, the focal length of the entire projection lens system is f0, the focal length of the I-th lens group is fI,
FII is the focal length of the second lens group, ndII1 is the refractive index of the lens closer to the screen of the cemented concave lens in the II lens group, and ndII1 is the refractive index of the lens farther from the screen of the cemented concave lens in the II lens group. The refractive index is ndII2, the Abbe number of the lens of the second lens group closer to the cemented concave lens screen is νdII1, the Abbe number of the lens of the second lens group farther from the cemented concave lens screen is νdII2, and The partial dispersion ratio (ng-nF) / (nF-nC) of the lens closer to the screen of the cemented concave lens of the II-th lens group to (g-nF) / (nF-nC) is PgFII1,
Partial dispersion ratio (ng-nF) / g line and F line of the lens farther from the screen of the cemented concave lens of the II lens group
When (nF-nC) is PgFII2 and the focal length of the cemented concave lens of the second lens group is fII12, the following expressions (1) to (6) are satisfied.

(1) 2.5 <| fI / f0 | (2) 1.8 <fII / f0 <4.5 (3) | ndII1-ndII2 | <0.001 (4) | νdII1-νdII2 | < 5 (5) 0.01 <| PgFII1-PgFII2 | (6) -5 <fII12 / f0 <-1.8 According to the first configuration of this projection lens, the axial ray is increased in the I-th lens group. As a result, distortion and chromatic aberration of magnification that occur in the concave lens group can be easily corrected while ensuring a long back focus.

A second configuration of the projection lens according to the present invention is a projection lens including an I lens group arranged in order from the screen side and a II lens group having a positive power, The I-th lens group includes a first negative meniscus lens having a convex surface directed toward the screen side, a biconvex lens, a second negative meniscus lens having a convex surface directed toward the screen side, which are arranged in order from the screen side. A positive meniscus lens having a concave surface directed to the side, and a biconcave lens. The second lens group includes a cemented concave lens and at least two convex lenses, which are sequentially arranged from the screen side. A diaphragm is provided in the lens group, the focal length of the entire projection lens system is f0, the focal length of the I-th lens group is fI, the focal length of the II-th lens group is fII, and the second lens group is fII.
The refractive index of the lens closer to the screen of the cemented concave lens of the II lens group is ndII1, and the refractive index of the lens of the second lens group distant from the screen of the cemented concave lens is nd.
II2, the Abbe number of the lens closer to the screen of the cemented concave lens of the II lens group is νdII1, the Abbe number of the lens of the cemented concave lens of the II lens group distant from the screen is νdII2, the II lens The partial dispersion ratio (ng-nF) / (nF-nC) of the lens closer to the screen of the cemented concave lens of the group to the g-line and F-line is PgFII
1. The partial dispersion ratio (ng-nF) / (nF-nC) of the lens farther from the screen of the cemented concave lens of the second lens group PgFII2, the cemented lens of the second lens group When the focal length of the concave lens is fII12, the following expressions (1) to (6) are satisfied.

(1) 2.5 <| fI / f0 | (2) 1.8 <fII / f0 <4.5 (3) | ndII1-ndII2 | <0.001 (4) | νdII1-νdII2 | < 5 (5) 0.01 <| PgFII1-PgFII2 | (6) -5 <fII12 / f0 <-1.8 According to the second configuration of this projection lens, the back focus is made relatively short and the optical system The whole can be made compact.

A third configuration of the projection lens according to the present invention is a projection lens comprising an I lens group arranged in order from the screen side and a II lens group having a positive power, The I-th lens group includes a first negative meniscus lens having a convex surface facing the screen side, a biconvex lens, and a second negative meniscus lens having a convex surface facing the screen side, which are arranged in order from the screen side. A cemented lens of a concave lens and a biconvex lens, wherein the second lens group has a cemented concave lens and at least two convex lenses, which are sequentially arranged from the screen side, and an aperture is provided in the first lens group. Is provided, the focal length of the entire projection lens system is f0, the focal length of the I-th lens group is fI, the focal length of the II-th lens group is fII, and it is close to the cemented concave lens screen of the II-lens group. The refractive index of the other lens is ndII
1. The refractive index of the lens farther from the screen of the cemented concave lens of the second lens group ndII2, the Abbe number of the lens of the lens closer to the screen of the cemented concave lens of the second lens group νdII1, the second lens II The Abbe number of the lens farther from the screen of the cemented concave lens of the group is vdI
I2, PgFII1, the partial dispersion ratio (ng-nF) / (nF-nC) of the lens closer to the screen of the cemented concave lens to the g-line and F-line to PgFII1, and the cemented lens of the II-th lens group Partial dispersion ratio (ng-nF) / (nF-n) for g-line and F-line of the lens far from the concave lens screen
C) is PgFII2, and the focal length of the cemented concave lens of the second lens group is fII12, the following formulas (1) to
It is characterized in that the relationship of (6) is satisfied.

(1) 2.5 <| fI / f0 | (2) 1.8 <fII / f0 <4.5 (3) | ndII1-ndII2 | <0.001 (4) | νdII1-νdII2 | < 5 (5) 0.01 <| PgFII1-PgFII2 | (6) -5 <fII12 / f0 <-1.8 According to the third configuration of this projection lens, the cemented concave lens of the II lens group and the Due to the effect of cementing the cemented lens of the biconcave lens and the biconvex lens in the lens group, it is possible to easily correct chromatic aberration of magnification.

A fourth configuration of the projection lens according to the present invention is a projection lens comprising an I lens group arranged in order from the screen side and a II lens group having a positive power, The I-th lens group includes, in order from the screen side, a negative meniscus lens having a convex surface facing the screen side, a cemented lens of a first positive meniscus lens having a concave surface facing the screen side and a biconcave lens, and a screen. A second positive meniscus lens having a convex surface directed to the side, and a biconvex lens, wherein the second lens group has a cemented concave lens and at least two convex lenses arranged in order from the screen side, A diaphragm is provided in the I-th lens group, the focal length of the entire projection lens system is f0, the focal length of the I-th lens group is fI, the focal length of the II-th lens group is fII, the II-lens group. , The refractive index of the lens closer to the screen of the cemented concave lens is ndII1, the refractive index of the lens of the second lens group farther from the screen of the cemented concave lens is ndII2, the screen of the cemented concave lens of the II lens group. The Abbe number of the lens closer to νdII
1. The Abbe number of the lens farther from the screen of the cemented concave lens of the II lens group is νdII2, and the partial dispersion ratio of the lens closer to the screen of the cemented concave lens of the II lens group to g line and F line (Ng-nF) / (nF-
nC) is PgFII1, the partial dispersion ratio (ng-nF) / (nF-nC) of the lens farther from the screen of the cemented concave lens of the second lens group is PgFII2, and the second lens group is the second lens group. The focal length of the cemented concave lens is fII1
When it is set to 2, it is characterized by satisfying the relationships of the following expressions (1) to (6).

(1) 2.5 <| fI / f0 | (2) 1.8 <fII / f0 <4.5 (3) | ndII1-ndII2 | <0.001 (4) | νdII1-νdII2 | < 5 (5) 0.01 <| PgFII1-PgFII2 | (6) -5 <fII12 / f0 <-1.8 According to the fourth configuration of this projection lens, the concave surface is directed toward the screen side of the I-th lens group. By the cementing effect of the cemented lens of the first positive meniscus lens and the biconcave lens, the principal ray is kept high at the position of the second positive meniscus lens having the convex surface toward the screen side having positive power and the biconvex lens. Therefore, the distortion aberration can be easily corrected.

A fifth configuration of the projection lens according to the present invention is a projection lens comprising an I lens group arranged in order from the screen side and a II lens group having a positive power, The I-th lens group includes a first negative meniscus lens having a convex surface facing the screen side, a cemented lens of a positive meniscus lens having a concave surface facing the screen side, and a biconcave lens, which are sequentially arranged from the screen side. A cemented lens of a convex lens and a second negative meniscus lens having a concave surface facing the screen, and a biconvex lens,
The II lens group includes a cemented concave lens and at least two convex lenses, which are sequentially arranged from the screen side, a diaphragm is provided in the I lens group, and the focal length of the entire projection lens system is f0. The focal length of the I-th lens group is fI, the focal length of the II-th lens group is fII, the refractive index of the lens closer to the screen of the cemented concave lens of the II-lens group is ndII1, and the refractive index of the II-lens group is The refractive index of the lens farther from the screen of the cemented concave lens is ndII2,
The Abbe number of the lens of the II lens group closer to the screen of the cemented concave lens is νdII1, the Abbe number of the lens of the lens group distant from the screen of the cemented concave lens of the II lens group is νdII2, and the cemented lens of the II lens group The partial dispersion ratio (ng-nF) / (nF-nC) of the concave lens closer to the screen to g-line and F-line is PgFII1,
Partial dispersion ratio (ng-nF) / g line and F line of the lens farther from the screen of the cemented concave lens of the lens group
When (nF-nC) is PgFII2 and the focal length of the cemented concave lens of the second lens group is fII12, the following expressions (1) to (6) are satisfied.

(1) 2.5 <| fI / f0 | (2) 1.8 <fII / f0 <4.5 (3) | ndII1-ndII2 | <0.001 (4) | νdII1-νdII2 | < 5 (5) 0.01 <| PgFII1-PgFII2 | (6) -5 <fII12 / f0 <-1.8 According to the fifth configuration of this projection lens, the concave surface is directed to the screen side of the I-th lens group. By the effect of cementing the cemented lens of the positive meniscus lens and the biconcave lens,
The biconvex lens having positive power, the second negative meniscus lens having a concave surface on the screen side, and the biconvex lens can be kept at high positions, so that distortion can be easily corrected and the second lens Due to the effect of cementing the cemented concave lens of the group, the biconvex lens of the I-th lens group, and the second negative meniscus lens having a concave surface facing the screen side, it is possible to easily correct chromatic aberration of magnification.

The sixth configuration of the projection lens according to the present invention is a projection lens comprising an I lens group arranged in order from the screen side and a II lens group having a positive power, The I-th lens group includes, in order from the screen side, a positive meniscus lens having a convex surface directed toward the screen side, a first negative meniscus lens having a convex surface directed toward the screen side, and a first meniscus lens having a convex surface directed toward the screen side. No. 2 negative meniscus lens, a biconcave lens, and a biconvex lens, and the second lens group II has a cemented concave lens and at least two convex lenses arranged in order from the screen side. A diaphragm is provided in the lens group, the focal length of the entire projection lens system is f0, the focal length of the I-th lens group is fI, the focal length of the II-th lens group is fII, and the second lens group is fII.
The refractive index of the lens closer to the screen of the cemented concave lens of the II lens group is ndII1, and the refractive index of the lens of the second lens group distant from the screen of the cemented concave lens is nd.
II2, the Abbe number of the lens closer to the screen of the cemented concave lens of the II lens group is νdII1, the Abbe number of the lens of the cemented concave lens of the II lens group distant from the screen is νdII2, the II lens The partial dispersion ratio (ng-nF) / (nF-nC) of the lens closer to the screen of the cemented concave lens of the group to the g-line and F-line is PgFII
1. The partial dispersion ratio (ng-nF) / (nF-nC) of the lens farther from the screen of the cemented concave lens of the second lens group PgFII2, the cemented lens of the second lens group When the focal length of the concave lens is fII12, the following expressions (1) to (6) are satisfied.

(1) 2.5 <| fI / f0 | (2) 1.8 <fII / f0 <4.5 (3) | ndII1-ndII2 | <0.001 (4) | νdII1-νdII2 | < 5 (5) 0.01 <| PgFII1-PgFII2 | (6) -5 <fII12 / f0 <-1.8 According to the sixth configuration of this projection lens, the lens closest to the screen of the I-th lens group is Since it is a positive meniscus lens, it is possible to easily correct distortion.

The seventh construction of the projection lens according to the present invention is a projection lens comprising an I lens group arranged in order from the screen side and a II lens group having a positive power, The I-th lens group includes a first positive meniscus lens having a convex surface directed toward the screen and a first positive lens having a convex surface directed toward the screen, which are arranged in order from the screen side.
Negative meniscus lens, a second negative meniscus lens having a convex surface facing the screen side, a cemented lens of a second positive meniscus lens having a concave surface facing the screen side and a biconcave lens, and a convex surface facing the screen side A third positive meniscus lens, the second lens group II has a cemented concave lens element and at least two convex lens elements arranged in order from the screen side, and a diaphragm is provided in the first lens element group I. And the focal length of the entire projection lens system is f0, the focal length of the I-th lens group is fI, the focal length of the II-lens group is fII, and the lens closer to the screen of the cemented concave lens of the II-lens group. The refractive index of ndII1, the lens of the second lens group farther from the screen of the cemented concave lens is ndII2, the one of the second lens group closer to the screen of the cemented concave lens νdII the Abbe number of the lens
1. The Abbe number of the lens farther from the screen of the cemented concave lens of the II lens group is νdII2, and the partial dispersion ratio of the lens closer to the screen of the cemented concave lens of the II lens group to g line and F line (Ng-nF) / (nF-
nC) is PgFII1, the partial dispersion ratio (ng-nF) / (nF-nC) of the lens farther from the screen of the cemented concave lens of the second lens group is PgFII2, and the second lens group is the second lens group. The focal length of the cemented concave lens is fII1
When it is set to 2, it is characterized by satisfying the relationships of the following expressions (1) to (6).

(1) 2.5 <| fI / f0 | (2) 1.8 <fII / f0 <4.5 (3) | ndII1-ndII2 | <0.001 (4) | νdII1-νdII2 | < 5 (5) 0.01 <| PgFII1-PgFII2 | (6) -5 <fII12 / f0 <-1.8 According to the seventh configuration of this projection lens, the lens closest to the screen of the I-th lens group is Since it is a positive meniscus lens, it is possible to easily correct distortion, and at the same time, a cemented concave lens of the II lens group, a second positive meniscus lens having a concave surface facing the screen side of the I lens group, and a biconcave lens. Due to the effect of cementing the cemented lens with, the chromatic aberration of magnification can be easily corrected.

An eighth configuration of the projection lens according to the present invention is a projection lens including an I lens group arranged in order from the screen side and a II lens group having a positive power, The I-th lens group includes a cemented lens of a first negative meniscus lens having a convex surface facing the screen side and a first positive meniscus lens having a convex surface facing the screen side, which are sequentially arranged from the screen side, and a screen side. A second negative meniscus lens having a convex surface directed to, a third negative meniscus lens having a convex surface directed to the screen side, a cemented lens of a second positive meniscus lens having a concave surface directed to the screen side and a biconcave lens, And a biconvex lens,
The II lens group includes a cemented concave lens and at least two convex lenses, which are sequentially arranged from the screen side, a diaphragm is provided in the I lens group, and the focal length of the entire projection lens system is f0. The focal length of the I-th lens group is fI, the focal length of the II-th lens group is fII, the refractive index of the lens closer to the screen of the cemented concave lens of the II-lens group is ndII1, and the refractive index of the II-lens group is The refractive index of the lens farther from the screen of the cemented concave lens is ndII2,
The Abbe number of the lens of the II lens group closer to the screen of the cemented concave lens is νdII1, the Abbe number of the lens of the lens group distant from the screen of the cemented concave lens of the II lens group is νdII2, and the cemented lens of the II lens group The partial dispersion ratio (ng-nF) / (nF-nC) of the concave lens closer to the screen to g-line and F-line is PgFII1,
Partial dispersion ratio (ng-nF) / g line and F line of the lens farther from the screen of the cemented concave lens of the lens group
When (nF-nC) is PgFII2 and the focal length of the cemented concave lens of the second lens group is fII12, the following expressions (1) to (6) are satisfied.

(1) 2.5 <| fI / f0 | (2) 1.8 <fII / f0 <4.5 (3) | ndII1-ndII2 | <0.001 (4) | νdII1-νdII2 | < 5 (5) 0.01 <| PgFII1-PgFII2 | (6) -5 <fII12 / f0 <-1.8 According to the eighth configuration of this projection lens, the convex surface is directed toward the screen side of the I-th lens group. Since the first negative meniscus lens and the first positive meniscus lens having a convex surface facing the screen side constitute a positive meniscus lens, it is possible to easily correct distortion and to form a cemented concave lens in the second lens group. , The first with the convex surface facing the screen side of the I-th lens group
Of the cemented lens of the negative meniscus lens and the first positive meniscus lens having the convex surface facing the screen side, and the cementing of the cemented lens of the second positive meniscus lens having the concave surface facing the screen side and the biconcave lens Due to the effect, the chromatic aberration of magnification can be easily corrected.

In the first to eighth structures of the projection lens of the present invention, it is preferable that at least two aspherical surfaces are provided. According to this preferable example, the distortion aberration can be easily corrected.

[0027]

Further, the configuration of the image enlarging and projecting system according to the present invention comprises a light source, a spatial light modulator which is illuminated by light emitted from the light source and which forms an optical image.
Projection means for projecting an optical image on the spatial light modulator, and the projection lens of the present invention is used as the projection means. According to the configuration of the image magnifying and projecting system, the optical image formed on the spatial light modulation element illuminated by the light source can be magnified and projected on the focus surface by the projecting unit. In this case, since the projection lens of the present invention is used as the projection means, it is possible to realize a compact image magnifying projection system with a short projection distance.

Further, the structure of the video projector according to the present invention comprises a light source, means for temporally limiting the light from the light source to three colors of blue, green and red, and illumination by the light emitted from the light source. 3 of blue, green, and red that change over time as they are played
It is characterized by comprising a spatial light modulation element for forming an optical image corresponding to a color and a projection means for projecting the optical image on the spatial light modulation element, wherein the projection lens of the present invention is used as the projection means. . According to the configuration of this video projector, the light from the light source is temporally decomposed into the three colors of blue, green and red by the means for temporally limiting the three colors of blue, green and red, and the spatial light modulation is performed. Illuminate the element. Three types of optical images of blue, green, and red are temporally divided and formed on the spatial light modulator, and enlarged and projected by the projection means. In this case, since the projection lens of the present invention is used as the projection means, the chromatic aberration of magnification is satisfactorily corrected, and blue, green, and red are included.
Since a color image can be projected on the screen without shifting, a high-definition image that is bright and has little color bleeding or distortion can be obtained. Also, since the projection distance is short,
It is possible to realize a video projector that can be used even in a narrow space.

The rear projector according to the present invention has a structure in which a video projector, a mirror that bends the light projected from the projection means in the video projector, and a transmissive screen that projects the projected light as an image. And a video projector of the present invention is used as the video projector. According to this configuration of the rear projector, the image projected from the video projector is reflected by the mirror and focused on the transmissive screen. In this case, since the video projector of the present invention equipped with a projection lens having a short projection distance is used as the video projector, the depth and height of the set can be suppressed to a small size, and a compact set can be realized. it can.

Further, the configuration of the multi-vision system according to the present invention comprises a plurality of systems comprising a video projector and a transmissive screen for projecting light projected from the projection means in the video projector as an image, and an image. And a video division circuit for dividing the video projection circuit according to the present invention as the video projector.
According to the configuration of this multi-vision system, the video signal is processed and divided by the video division circuit and sent to the plurality of video projectors. The image projected from the video projector is imaged on the transmissive screen. In this case, since the video projector of the present invention having a projection lens with a short projection distance is used as the video projector, a compact set with a short depth can be realized.

[0032]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail below with reference to embodiments.

In the present invention, a suitable lens arrangement is used to realize a large angle of view and a long back focus while satisfying distortion, telecentricity, and chromatic aberration of magnification.

In order to obtain telecentricity, it is necessary to bend the chief ray from a half angle of view according to the specifications of the lens to the horizontal. For this reason, the chief ray is largely bent as compared with a lens having no telecentricity.
This imposes a great burden on correction of distortion and chromatic aberration of magnification.

It is known that it is advantageous to adopt a symmetric configuration with respect to the diaphragm when correcting distortion and chromatic aberration of magnification, but as long as it is telecentric, symmetry of the chief ray cannot be obtained. . In order to obtain a longer back focus, the configuration is an inverse telephoto type, and the concave lens in the front part is a source of distortion and chromatic aberration of magnification.

In the present invention, a cemented lens having a combination of a small difference in refractive index and a small difference in Abbe number and a large difference in partial dispersion ratio is arranged in the rear of the diaphragm to correct lateral chromatic aberration. Is being done.

The final positive lens group requires a large power in order to realize telecentricity, but even if it is composed of a lens with a large Abbe number, the chief ray height is high, so F
Lines and g lines are refracted to a greater extent than d lines, causing chromatic aberration of magnification.

It is the negative lens located on the screen side of the final positive lens group that corrects the chromatic aberration of this magnification. This negative lens is composed of glass with a small Abbe number to correct chromatic aberration of magnification, but since the Abbe number and the partial dispersion ratio are in inverse proportion, glass with a small Abbe number has a large partial dispersion ratio. . Therefore, if the lateral chromatic aberration is corrected with the F line, the g line will be overcorrected.

To alleviate this tendency, it is desirable to use lanthanum flint type glass instead of flint or heavy flint as the glass for the negative lens. Since the lanthanum flint type glass has a smaller partial dispersion ratio with respect to the Abbe number than that of the heavy flint glass, it is possible to suppress overcorrection at the g line. However, since the lanthanum flint type glass has a larger Abbe number than that of the heavy flint glass, the correction of the chromatic aberration of the magnification at the F line is insufficient and a sufficient correction state cannot be obtained.

In the present invention, by using the above-mentioned cemented lens, it is possible to correct lateral chromatic aberration at each wavelength of C-line, d-line, e-line, F-line and g-line. In each of the examples described below, the refractive index of the d line is 1.74 and the Abbe number of the d line is 3 as the glass of the concave lens of the cemented lens on the screen side.
1.7, a glass having a partial dispersion ratio of g-line to F-line of 0.5906 is used, and as a glass for a convex lens on the non-screen side, the refractive index of d-line is 1.74077 and the Abbe number of d-line is 27. 76, partial dispersion ratio of g-line and F-line is 0.60794
6 glasses are used. The composite Abbe number of the cemented lens is 35.89, and the composite partial dispersion ratio is 0.572. As a glass having a similar Abbe number to this synthetic Abbe number, there is a lanthanum flint glass having a d-line refractive index of 1.92250 and a d-line Abbe number of 35.95, but there is a partial dispersion of g-line and F-line. The ratio is 0.578, which is larger than that of the cemented lens of the present invention. Therefore, the use of the cemented lens of the present invention is more effective than the use of the lanthanum flint glass in reducing the partial dispersion ratio and the chromatic aberration of magnification.

<First Embodiment> First, the first embodiment of the present invention will be described.
The projection lens of the embodiment will be described with reference to the drawings. FIG. 1 is a layout diagram showing the configuration of the projection lens in the present embodiment.

As shown in FIG. 1, the projection lens of the present embodiment has an I-th lens group GI and a II-th lens arranged in order from the screen side (left side in FIG. 1) on a common optical axis. And group GII.

The I-th lens group GI includes a positive meniscus lens I1 having a convex surface facing the screen side, a negative meniscus lens I2 having a convex surface facing the screen side, and a convex surface facing the screen side, which are arranged in order from the screen side. A negative meniscus lens I3, a biconcave lens I4 having a small radius of curvature facing the screen side, a biconvex lens I5, a biconvex lens I6, a biconvex lens I7, and a negative meniscus lens I8 having a concave surface on the screen side. It is composed of a cemented lens.

The second lens group GII includes a cemented lens of a biconcave lens II1 and a positive meniscus lens II2 having a convex surface facing the screen, which are sequentially arranged from the screen side, a positive lens II3, a positive lens II4, and a positive lens II4. It is composed of a lens II5.

The biconvex lens I in the I-th lens group GI
A diaphragm S is arranged between the lens 5 and the biconvex lens I6.

Further, a spatial light modulator III1 is arranged on the side opposite to the screen of the second lens group GII, and a prism III2 is arranged between the spatial light modulator III1 and the lens group.

As described above, since the prism III2 is interposed between the spatial light modulation element III1 and the projection lens (the first lens group GI and the second lens group GII), the space between the projection lens and the spatial light modulation element III1 is increased. Requires a long air gap. That is, a long back focus is required. Further, in order to prevent color unevenness and brightness unevenness due to the incident angle dependence of the prism III2, it is necessary that the telecentricity is good.

In the projection lens of this embodiment, the focal length of the entire projection lens system is f0, the focal length of the I-th lens group GI is fI, the focal length of the II-th lens group GII is fII, and the II-lens group GII is The refractive index of the biconcave lens II1 is ndII1, the refractive index of the positive meniscus lens II2 of the second lens group GII is ndII2,
The Abbe number of the biconcave lens II1 of the II lens group GII is νdII
1, the Abbe number of the positive meniscus lens II2 of the second lens group GII is νdII2, and the partial dispersion ratio (ng-nF) / (nF-nC) of the biconcave lens II1 of the second lens group GII to the g line and the F line
PgFII1, a positive meniscus lens of the second lens group GII
Partial dispersion ratio (ng-nF) / (nF) of II2 for g-line and F-line
-NC) is PgFII2 and the focal length of the cemented lens of the second lens group GII is fII12, the following formulas (1) to (6)
Are satisfied with the relationship.

(1) 2.5 <| fI / f0 | (2) 1.8 <fII / f0 <4.5 (3) | ndII1-ndII2 | <0.001 (4) | νdII1-νdII2 | < 5 (5) 0.01 <| PgFII1-PgFII2 | (6) -5 <fII12 / f0 <-1.8 The above formula (1) is a formula relating to the power of the I-th lens group GI. When fI / f0 becomes −2.5 or less, distortion cannot be corrected. When fI / f0 is 2.5 or more, the back focus cannot be secured.

The above equation (2) is an equation relating to the power of the second lens group GII. When fII / f0 becomes 1.8 or less, it becomes impossible to correct distortion and lateral chromatic aberration. When fII / f0 is 4.5 or more, it becomes impossible to correct field curvature and coma.

The above formula (3) is a formula relating to the difference in refractive index with respect to the d-line of the two lenses (the biconcave lens II1 and the positive meniscus lens II2) which form the cemented lens of the second lens group GII. When | ndII1-ndII2 | becomes 0.001 or more, it becomes impossible to correct lateral chromatic aberration.

The above formula (4) is a formula relating to the difference in Abbe number with respect to the d-line of the two lenses (the biconcave lens II1 and the positive meniscus lens II2) which form the cemented lens of the second lens group GII. When | νdII1-νdII2 | becomes 5 or more,
It becomes impossible to correct chromatic aberration of magnification.

The above formula (5) is a formula relating to the difference in the partial dispersion ratios of the two lenses (the biconcave lens II1 and the positive meniscus lens II2) constituting the cemented lens of the second lens group GII with respect to the g-line and the F-line. is there. If | PgFII1-PgFII2 | becomes 0.01 or less, it becomes impossible to correct lateral chromatic aberration.

The above equation (6) is an equation relating to the power of the cemented lens of the second lens group GII. fII12 / f0 is-
When it is 5 or less, the telecentricity cannot be satisfied. When fII12 / f0 is -1.8 or more, it becomes impossible to correct distortion and lateral chromatic aberration.

The projection lens of this embodiment will be described below with reference to specific examples.

(Example 1) In this example, the F number F _NO
= 3.0, focal length f = 10.37, half angle of view ω = 43 °
In the projection lens having the configuration shown in FIG.
By satisfying the relationships (1) to (6), the back focus is long, the telecentricity is satisfied, and the distortion and the chromatic aberration of magnification are corrected.

Specific values are shown in the following (Table 1). In the following (Table 1), ri is the radius of curvature of each surface of the lens, di is the lens thickness or inter-lens spacing, ni is the refractive index at the d-line of each lens, and νi is the Abbe number at the d-line of each lens. . Further, the aspherical shape is a rotationally symmetric aspherical surface represented by the following (Formula 1), where X is a displacement amount from the lens apex at the position of the radial distance h of the opening from the optical axis of the lens.

[0058]

[Equation 1]

[0059]

[Table 1]         f0 = 10.37, aperture ratio 1: 3.0, ω = 43 °         fI / f0 = -215.9         fII / f0 = 4.05         ndII1-ndII2 = -0.00077         νdII1-νdII2 = 3.94         PgFII1-PgFII2 = -0.0173         fII12 / f0 = -4.18                         Axis between faces       Surface radius (mm) Direction distance (mm) Nd νd     r1 = 48.219 d1 = 3.0 n1 = 1.77250 ν1 = 49.62     r2 = 53.544 d2 = 0.5     r3 = 21.123 d3 = 1.5 n2 = 1.77250 ν2 = 49.62     r4 = 9.197 d4 = 7.0     r5 = 27.128 d5 = 1.5 n3 = 1.77250 ν3 = 49.62     r6 = 9.633 d6 = 7.0     r7 = -19.253 d7 = 2.0 n4 = 1.77250 ν4 = 49.62     r8 = 921.365 d8 = 4.0     r9 = 59.031 d9 = 5.0 n5 = 1.78800 ν5 = 47.49     r10 = -1655.729 d10 = 1.0     r11 = 59.633 d11 = 2.9 n6 = 1.80450 ν6 = 39.64     r12 = -44.333 d12 = 3.0     r13 = 0.0 d13 = 3.8     r14 = 2071.084 d14 = 6.1 n7 = 1.56384 ν7 = 60.83     r15 = -18.620 d15 = 1.3 n8 = 1.74000 ν8 = 31.7     r16 = -43.557 d16 = 14.0     r17 = -133.206 d17 = 1.9 n9 = 1.74000 ν9 = 31.7     r18 = 21.886 d18 = 3.5 n10 = 1.74077 ν10 = 27.76     r19 = 43.255 d19 = 1.1     r20 = -233.308 d20 = 5.6 n11 = 1.49700 ν11 = 81.5     r21 = -50.519 d21 = 0.3     r22 = 187.323 d22 = 6.4 n12 = 1.49700 ν12 = 81.5     r23 = -53.707 d23 = 0.3     r24 = 41.313 d24 = 7.3 n13 = 1.49700 ν13 = 81.5     r25 = -58.833 d25 = 30.0     r26 = 0.0 d26 = 24.0 n14 = 1.51680 v14 = 64.2     r27 = 0.0 d27 = 1.4 The aspherical coefficients of each surface are shown below.

Aspherical coefficient of five surfaces A4 = 2.06598 × 10 ^-4 A6 = 4.16479 × 10 ^-6 A8 = -3.41833 × 10 ^-8 A10 = 0.0 Seven surface aspherical coefficient A4 = -8.93742 × 10 ^-5 A6 = -1.66492 × 10 ^-5 A8 = 4.326 14 × 10 ^-7 A10 = 0.0 FIGS. 2A, 2B, and 2C show the spherical aberration, astigmatism, and distortion of the projection lens in this example.

According to this embodiment, the half angle of view ω = 43 °
With a wide angle, a long back focus and telecentricity are satisfied, and distortion and chromatic aberration of magnification are sufficiently corrected.

<Second Embodiment> Next, the second embodiment of the present invention will be described.
The projection lens of the embodiment will be described with reference to the drawings. FIG. 3 is an arrangement diagram showing the configuration of the projection lens in the present embodiment.

As shown in FIG. 3, the projection lens according to the present embodiment has an I-th lens group GI and a II-th lens arranged in order from the screen side (left side in FIG. 3) on a common optical axis. And group GII.

The I-th lens group GI includes a negative meniscus lens I1 having a convex surface directed toward the screen, a biconvex lens I2, a negative meniscus lens I3 having a convex surface directed toward the screen, and a screen arranged in order from the screen side. A positive meniscus lens I4 having a concave surface facing the side and a biconcave lens I4
5, a biconvex lens I6, and a cemented lens of a biconvex lens I7 and a negative meniscus lens I8 having a concave surface facing the screen side. The structure of the second lens group GII is the same as that of the first embodiment.

The biconvex lens I in the I-th lens group GI
A diaphragm S is arranged between 6 and the biconvex lens I7.

Further, a spatial light modulator III1 is arranged on the side opposite to the screen of the second lens group GII, and a prism III2 is arranged between the spatial light modulator III1 and the lens group.

The projection lenses of the present embodiment also satisfy the above expressions (1) to (6).

The projection lens of this embodiment will be described below with reference to specific examples.

(Embodiment 2) In this embodiment, the F number F _NO
= 3.0, the focal length f = 10.7, and the half angle of view ω = 43 ° in the projection lens of the configuration shown in FIG.
By satisfying the relationship of (6), the back focus is long, the telecentricity is satisfied, and
It is designed for the purpose of correcting distortion and chromatic aberration of magnification.

Specific values are shown in the following (Table 2). Each symbol in the following (Table 2) is the same as in the case of Example 1 above. Further, the aspherical shape is a rotationally symmetric aspherical surface represented by the above (Formula 1), where X is a displacement amount from the lens apex at the position of the radial distance h of the opening from the optical axis of the lens.

[0071]

[Table 2]         f0 = 10.7, aperture ratio 1: 3.0, ω = 43 °         fI / f0 = 6.3         fII / f0 = 2.5         ndII1-ndII2 = -0.00077         νdII1-νdII2 = 3.94         PgFII1-PgFII2 = -0.0173         fII12 / f0 = -2.73                         Axis between faces       Surface radius (mm) Direction distance (mm) Nd νd     r1 = 44.014 d1 = 2.1 n1 = 1.69100 ν1 = 54.7     r2 = 11.839 d2 = 5.0     r3 = 35.308 d3 = 3.2 n2 = 1.71736 ν2 = 29.5     r4 = -42.208 d4 = 0.5     r5 = 48.794 d5 = 1.6 n3 = 1.66546 ν3 = 55.42     r6 = 6.921 d6 = 5.3     r7 = -23.512 d7 = 3.2 n4 = 1.66546 ν4 = 55.42     r8 = -7.528 d8 = 0.5     r9 = -54.438 d9 = 2.1 n5 = 1.66546 ν5 = 55.42     r10 = 19.115 d10 = 4.7     r11 = 76.645 d11 = 3.1 n6 = 1.68712 ν6 = 31.08     r12 = -51.788 d12 = 0.8     r13 = 1593.370 d13 = 3.2 n7 = 1.56384 ν7 = 60.83     r14 = -14.325 d14 = 1.0 n8 = 1.74000 ν8 = 31.7     r15 = -33.510 d15 = 6.3     r16 = -89.687 d16 = 1.3 n9 = 1.74000 ν9 = 31.7     r17 = 14.736 d17 = 2.3 n10 = 1.74077 ν10 = 27.76     r18 = 29.124 d18 = 0.8     r19 = -109.312 d19 = 3.8 n11 = 1.49700 ν11 = 81.5     r20 = -18.031 d20 = 0.2     r21 = 152.040 d21 = 4.3 n12 = 1.49700 ν12 = 81.5     r22 = -36.922 d22 = 0.2     r23 = 20.888 d23 = 4.9 n13 = 1.49700 ν13 = 81.5     r24 = 251.657 d24 = 7.1     r25 = 0.0 d25 = 24.0 n14 = 1.51680 ν14 = 64.2     r26 = 0.0 d26 = 0.3 The aspherical surface coefficient of each surface is shown below.

Aspherical coefficient of 6 surfaces A4 = 2.80585 × 10 ^-5 A6 = -1.57106 × 10 ^-5 A8 = 3.77659 × 10 ^-7 A10 = -4.0231 × 10 ^-9 Aspherical coefficient of 8 surfaces A4 = 1.03552 × 10 ^-3 A6 = -1.57717 x 10 ^-5 A8 = 1.77342 x 10 ^-7 A10 = 0.0 Aspherical surface coefficient A4 = -1.22782 x 10 ^-3 A6 = 3.41760 x 10 ^-5 A8 = -3.55817 x 10 ^-7 A10 = 0.0 11 Aspherical coefficient of the surface A4 = -1.27879 × 10 ^-4 A6 = 7.08344 × 10 ^-6 A8 = -8.80713 × 10 ^-8 A10 = 0.0 Figure 4 (a), (b), (c) 7 shows spherical aberration, astigmatism, and distortion of the projection lens in Examples.

According to this embodiment, the first lens group GI
Even if the negative meniscus lens I1 and the biconvex lens I2 are arranged in this order from the screen side, the long back focus and the telecentricity are satisfied while the half angle of view ω = 43 ° and the wide angle are satisfied. Chromatic aberration is sufficiently corrected.

<Third Embodiment> Next, the third embodiment of the present invention will be described.
The projection lens of the embodiment will be described with reference to the drawings. FIG. 5 is an arrangement diagram showing the configuration of the projection lens in the present embodiment.

As shown in FIG. 5, the projection lens according to the present embodiment has an I-th lens group GI and a II-th lens arranged in order from the screen side (left side in FIG. 5) on a common optical axis. And group GII.

The I-th lens group GI includes, in order from the screen side, a negative meniscus lens I1 having a convex surface facing the screen side, a biconvex lens I2, a negative meniscus lens I3 having a convex surface facing the screen side, and both lenses. Concave lens I4
And a biconvex lens I5, and a biconcave lens I6
And a positive meniscus lens I with a concave surface facing the screen side
7 and a cemented lens of a biconvex lens I8 and a negative meniscus lens I9 having a concave surface facing the screen side. The structure of the second lens group GII is the same as that of the first embodiment.

The biconvex lens I in the I-th lens group GI
A diaphragm S is arranged between the lens 7 and the biconvex lens I8.

Further, a spatial light modulation element III1 is arranged on the side opposite to the screen of the second lens group GII, and a prism III2 is arranged between the spatial light modulation element III1 and the lens group.

The projection lenses of the present embodiment also satisfy the above expressions (1) to (6).

The projection lens of this embodiment will be described below with reference to specific examples.

(Embodiment 3) In this embodiment, the F number F _NO
= 3.0, the focal length f = 10.7, and the half angle of view ω = 43 ° in the projection lens having the configuration shown in FIG.
By satisfying the relationship of (6), the back focus is long, the telecentricity is satisfied, and
It is designed for the purpose of correcting distortion and chromatic aberration of magnification.

Specific values are shown in the following (Table 3). Each symbol in the following (Table 3) is the same as in Example 1 above. Further, the aspherical shape is a rotationally symmetric aspherical surface represented by the above (Formula 1), where X is a displacement amount from the lens apex at the position of the radial distance h of the opening from the optical axis of the lens.

[0083]

[Table 3]         f0 = 10.7, aperture ratio 1: 3.0, ω = 43 °         fI / f0 = 3.06         fII / f0 = 2.68         ndII1-ndII2 = -0.00077         νdII1-νdII2 = 3.94         PgFII1-PgFII2 = -0.0173         fII12 / f0 = -2.73                         Axis between faces       Surface radius (mm) Direction distance (mm) Nd νd     r1 = 44.014 d1 = 2.1 n1 = 1.69100 ν1 = 54.7     r2 = 11.839 d2 = 5.0     r3 = 52.355 d3 = 3.2 n2 = 1.76180 ν2 = 26.91     r4 = -44.453 d4 = 0.5     r5 = 30.872 d5 = 1.6 n3 = 1.66546 ν3 = 55.42     r6 = 7.647 d6 = 5.3     r7 = -23.175 d7 = 1.5 n4 = 1.49700 ν4 = 81.5     r8 = 28.995 d8 = 4.5 n5 = 1.66546 ν5 = 55.42     r9 = -8.188 d9 = 0.5     r10 = -34.077 d10 = 2.1 n6 = 1.66546 ν6 = 55.42     r11 = 13.654 d11 = 4.6     r12 = -73.149 d12 = 3.0 n7 = 1.66546 ν7 = 55.42     r13 = -16.435 d13 = 0.7     r14 = 1593.369 d14 = 3.1 n8 = 1.56384 ν8 = 60.83     r15 = -14.325 d15 = 1.0 n9 = 1.74000 ν9 = 31.7     r16 = -33.510 d16 = 7.0     r17 = -89.687 d17 = 1.2 n10 = 1.74000 ν10 = 31.7     r18 = 14.735 d18 = 2.3 n11 = 1.74077 ν11 = 27.76     r19 = 29.123 d19 = 3.7     r20 = -45.070 d20 = 5.1 n12 = 1.49700 ν12 = 81.5     r21 = -14.838 d21 = 1.0     r22 = -132.221 d22 = 4.3 n13 = 1.49700 ν13 = 81.5     r23 = -37.312 d23 = 0.5     r24 = 24.357 d24 = 4.9 n14 = 1.49700 ν14 = 81.5     r25 = 306.211 d25 = 7.0     r26 = 0.000 d26 = 24.0 n15 = 1.51680 ν15 = 64.2     r27 = 0.000 d27 = 2.3 The aspherical surface coefficient of each surface is shown below.

Aspherical coefficient of 6 surfaces A4 = 1.18467 × 10 ^-4 A6 = -1.64323 × 10 ^-5 A8 = 4.87396 × 10 ^-7 A10 = -6.11554 × 10 ^-9 Aspherical coefficient of 9 surfaces A4 = 8.41633 × 10 -4 A6 = -1.24330 × 10 ^-5 A8 = 1.49025 × 10 ^-7 A10 = 0.0 11 Aspherical surface coefficient A4 = -9.81060 × 10 ^-4 A6 = 2.78845 × 10 ^-5 A8 = -3.13363 × 10 ^-7 A10 = 0.0 12 surface aspherical coefficient A4 = -1.06860 × 10 ^-4 A6 = 6.33588 × 10 ^-6 A8 = -8.98549 × 10 ^-8 A10 = 0.0 Figure 6 (a), (b), (c) 7 shows spherical aberration, astigmatism, and distortion of the projection lens in Examples.

According to this embodiment, the I-th lens group GI
Are arranged in order of the negative meniscus lens I1 and the biconvex lens I2 from the screen side, and the biconcave lens I4 and the biconvex lens I
Since 5 and 5 are joined, it is easy to correct lateral chromatic aberration, and a wide angle of half field angle ω = 43 °,
Long back focus and telecentricity are satisfied, and distortion and lateral chromatic aberration are sufficiently corrected.

<Fourth Embodiment> Next, a fourth embodiment of the present invention will be described.
The projection lens of the embodiment will be described with reference to the drawings. FIG. 7 is an arrangement diagram showing the configuration of the projection lens in the present embodiment.

As shown in FIG. 7, the projection lens of the present embodiment has an I-th lens group GI and a II-th lens arranged in order from the screen side (left side in FIG. 7) on a common optical axis. And group GII.

The I-th lens group GI is a cemented lens of a negative meniscus lens I1 having a convex surface facing the screen side, a positive meniscus lens I2 having a concave surface facing the screen side, and a biconcave lens I3, which are sequentially arranged from the screen side. And a positive meniscus lens I4 having a convex surface on the screen side,
It is composed of a biconvex lens I5, a negative meniscus lens I6 having a convex surface facing the screen side, and a cemented lens of a biconvex lens I7 and a negative meniscus lens I8 having a concave surface facing the screen side. The structure of the second lens group GII is the same as that of the first embodiment.

The biconvex lens I in the I-th lens group GI
A diaphragm S is arranged between 6 and the biconvex lens I7.

Further, a spatial light modulation element III1 is arranged on the opposite screen side of the second lens group GII, and a prism III2 is arranged between the spatial light modulation element III1 and the lens group.

The projection lenses of the present embodiment also satisfy the above expressions (1) to (6).

The projection lens of this embodiment will be described below with reference to specific examples.

(Embodiment 4) In this embodiment, the F number F _NO
= 3.0, the focal length f = 10.7, and the half angle of view ω = 43 ° in the projection lens having the configuration shown in FIG.
By satisfying the relationship of (6), the back focus is long, the telecentricity is satisfied, and
It is designed for the purpose of correcting distortion and chromatic aberration of magnification.

Specific values are shown in the following (Table 4). Each symbol in the following (Table 4) is the same as in Example 1 above. Further, the aspherical shape is a rotationally symmetric aspherical surface represented by the above (Formula 1), where X is a displacement amount from the lens apex at the position of the radial distance h of the opening from the optical axis of the lens.

[0095]

[Table 4]         f0 = 10.7, aperture ratio 1: 3.0, ω = 43 °         fI / f0 = 4.88         fII / f0 = 2.63         ndII1-ndII2 = -0.00077         νdII1-νdII2 = 3.94         PgFII1-PgFII2 = -0.0173         fII12 / f0 = -2.73                         Axis between faces       Surface radius (mm) Direction distance (mm) Nd νd     r1 = 25.197 d1 = 2.1 n1 = 1.69100 ν1 = 54.7     r2 = 12.382 d2 = 5.3     r3 = -39.853 d3 = 5.0 n2 = 1.75520 ν2 = 27.53     r4 = -25.000 d4 = 3.0 n3 = 1.66546 ν3 = 55.42     r5 = 10.172 d5 = 3.0     r6 = 22.106 d6 = 15.6 n4 = 1.74950 ν3 = 35     r7 = 86.812 d7 = 0.5     r8 = 27.639 d8 = 2.1 n5 = 1.66546 ν5 = 55.42     r9 = -44.543 d9 = 4.6     r10 = 71.730 d10 = 3.0 n6 = 1.66546 ν6 = 55.42     r11 = 51.606 d11 = 0.7     r12 = 1593.369 d12 = 3.1 n7 = 1.56384 ν7 = 60.83     r13 = -14.325 d13 = 1.0 n8 = 1.74000 ν8 = 31.7     r14 = -33.510 d14 = 6.2     r15 = -89.687 d15 = 1.2 n9 = 1.74000 ν9 = 31.7     r16 = 14.735 d16 = 2.3 n10 = 1.74077 ν10 = 27.76     r17 = 29.123 d17 = 0.7     r18 = -60.655 d18 = 3.7 n11 = 1.49700 ν11 = 81.5     r19 = -13.145 d19 = 0.1     r20 = 185.021 d20 = 4.3 n12 = 1.49700 ν12 = 81.5     r21 = -32.690 d21 = 0.1     r22 = 50.241 d22 = 4.9 n13 = 1.49700 ν13 = 81.5     r23 = -168.982 d23 = 7.0     r24 = 0.000 d24 = 24.0 n14 = 1.51680 ν15 = 64.2     r25 = 0.000 d25 = 0.2 The aspherical surface coefficient of each surface is shown below.

Aspherical surface coefficient A4 = -3.20071 × 10 ^-4 A6 = 1.11983 × 10 ^-6 A8 = -1.94202 × 10 ^-8 A10 = 0.0 9 Aspherical surface coefficient A4 = 1.06292 × 10 ^-4 A6 = 4.89329 × 10 ^-7 A8 = 0.0 A10 = 0.0 10 surface aspherical coefficient A4 = 4.71461 × 10 ^-5 A6 = 2.92440 × 10 ^-7 A8 = 0.0 A10 = 0.0 Figs. 8 (a), (b), (c) The spherical aberration, astigmatism, and distortion of the projection lens in this example are shown in FIG.

According to this embodiment, the I-th lens group GI
Is arranged in order of the negative meniscus lens I1, the positive meniscus lens I2, and the biconcave lens I3 from the screen side, the long back focus and telecentricity are achieved even though the half field angle ω = 43 ° and the wide angle. Is satisfied, and distortion and chromatic aberration of magnification are sufficiently corrected.

<Fifth Embodiment> Next, the fifth embodiment of the present invention will be described.
The projection lens of the embodiment will be described with reference to the drawings. FIG. 9 is a layout diagram showing the configuration of the projection lens in the present embodiment.

As shown in FIG. 9, the projection lens according to the present embodiment has the I-th lens group GI and the II-th lens arranged in order from the screen side (the left side in FIG. 9) on the common optical axis. And group GII.

The I-th lens group GI is a cemented lens of a negative meniscus lens I1 having a convex surface facing the screen side, a positive meniscus lens I2 having a concave surface facing the screen side, and a biconcave lens I3, which are sequentially arranged from the screen side. A cemented lens of a biconvex lens I4 and a negative meniscus lens I5 having a concave surface facing the screen, a biconvex lens I6, a biconcave lens I7, a biconvex lens I8, and a negative meniscus lens I9 having a concave surface facing the screen. It is composed of a cemented lens. The configuration of the second lens group GII is
It is similar to the first embodiment.

The biconcave lens I in the I-th lens group GI
A diaphragm S is arranged between the lens 7 and the biconvex lens I8.

Further, a spatial light modulation element III1 is arranged on the side opposite to the screen of the second lens group GII, and a prism III2 is arranged between the spatial light modulation element III1 and the lens group.

The projection lenses of the present embodiment also satisfy the above expressions (1) to (6).

The projection lens of this embodiment will be described below with reference to specific examples.

(Embodiment 5) In this embodiment, the F number F _NO
= 3.0, the focal length f = 10.7, and the half angle of view ω = 43 ° in the projection lens having the configuration shown in FIG.
By satisfying the relationship of (6), the back focus is long, the telecentricity is satisfied, and
It is designed for the purpose of correcting distortion and chromatic aberration of magnification.

Specific values are shown in the following (Table 5). Each symbol in the following (Table 5) is the same as in Example 1 above. Further, the aspherical shape is a rotationally symmetric aspherical surface represented by the above (Formula 1), where X is a displacement amount from the lens apex at the position of the radial distance h of the opening from the optical axis of the lens.

[0107]

[Table 5]         f0 = 10.7, aperture ratio 1: 3.0, ω = 43 °         fI / f0 = 9.21         fII / f0 = 2.26         ndII1-ndII2 = -0.00077         νdII1-νdII2 = 3.94         PgFII1-PgFII2 = -0.0173         fII12 / f0 = -2.73                         Axis between faces       Surface radius (mm) Direction distance (mm) Nd νd     r1 = 25.197 d1 = 2.1 n1 = 1.69100 ν1 = 54.7     r2 = 12.382 d2 = 5.5     r3 = -40.715 d3 = 4.5 n2 = 1.75520 ν2 = 27.53     r4 = -26.672 d4 = 3.0 n3 = 1.66546 ν3 = 55.42     r5 = 9.846 d5 = 3.0     r6 = 30.098 d6 = 10.0 n4 = 1.74950 ν4 = 35     r7 = -40.589 d7 = 2.7 n5 = 1.75211 ν5 = 25.1     r8 = -94.683 d8 = 0.5     r9 = 38.575 d9 = 2.1 n6 = 1.66546 ν6 = 55.42     r10 = -23.250 d10 = 4.6     r11 = -416.044 d11 = 3.0 n7 = 1.66546 ν7 = 55.42     r12 = 31.921 d12 = 0.7     r13 = 1593.369 d13 = 3.1 n8 = 1.56384 ν8 = 60.83     r14 = -12.495 d14 = 1.0 n9 = 1.74000 ν9 = 31.7     r15 = -33.510 d15 = 7.0     r16 = -89.687 d16 = 1.2 n10 = 1.74000 ν10 = 31.7     r17 = 14.735 d17 = 2.3 n11 = 1.74077 ν11 = 27.76     r18 = 29.123 d18 = 1.5     r19 = -1489.102 d19 = 4.5 n12 = 1.49700 ν12 = 81.5     r20 = -14.683 d20 = 0.9     r21 = -115.070 d21 = 4.3 n13 = 1.49700 ν13 = 81.5     r22 = -30.839 d22 = 0.1     r23 = 54.940 d23 = 4.9 n14 = 1.49700 ν14 = 81.5     r24 = -44.825 d24 = 7.0     r25 = 0.000 d25 = 24.0 n15 = 1.51680 ν15 = 64.2     r26 = 0.000 d26 = 0.2 The aspherical coefficients of each surface are shown below.

Aspherical coefficient of 5 surfaces A4 = -2.98684 × 10 ^-4 A6 = 9.97723 × 10 ^-7 A8 = -2.03662 × 10 ^-8 A10 = 0.0 Aspherical coefficient of 10 surface A4 = 7.76778 × 10 ^-5 A6 = -2.47327 × 10 ^-7 A8 = 0.0 A10 = 0.0 11 Aspherical surface coefficient A4 = 4.07966 × 10 ^-5 A6 = -6.67566 × 10 ^-8 A8 = 0.0 A10 = 0.0 FIGS. 10 (a), (b), ( c) shows spherical aberration, astigmatism, and distortion of the projection lens in this example.

According to this embodiment, the I-th lens group GI
Is arranged in order of the negative meniscus lens I1, the positive meniscus lens I2, and the biconcave lens I3 from the screen side, and the biconvex lens I4 and the negative meniscus lens I5 are cemented, so that it is easy to correct chromatic aberration of magnification. At the same time, the wide angle of view is ω = 43 ° and the long back focus and telecentricity are satisfied.
The distortion and the chromatic aberration of magnification are sufficiently corrected.

<Sixth Embodiment> Next, the sixth embodiment of the present invention will be described.
The projection lens of the embodiment will be described with reference to the drawings. FIG. 11 is an arrangement diagram showing the configuration of the projection lens in the present embodiment.

As shown in FIG. 11, the projection lens according to the present embodiment has the I-th lens group GI and the II-th lens group GI arranged in order from the screen side (left side in FIG. 11) on the common optical axis.
The lens group GII.

The I-th lens group GI includes a positive meniscus lens I1 having a convex surface facing the screen side, a negative meniscus lens I2 having a convex surface facing the screen side, and a convex surface facing the screen side, which are arranged in order from the screen side. Negative meniscus lens I3, biconcave lens I4, and biconvex lens I
5 and a cemented lens of a biconvex lens I6 and a negative meniscus lens I7 having a concave surface facing the screen side. The structure of the second lens group GII is the same as that of the first embodiment.

The biconvex lens I in the I-th lens group GI
A diaphragm S is arranged between the lens 5 and the biconvex lens I6.

Further, a spatial light modulation element III1 is arranged on the opposite screen side of the second lens group GII, and a prism III2 is arranged between the spatial light modulation element III1 and the lens group.

The projection lenses of the present embodiment also satisfy the above expressions (1) to (6).

The projection lens of this embodiment will be described below with reference to specific examples.

(Embodiment 6) In this embodiment, the F number F _NO
= 3.0, the focal length f = 10.7, and the half angle of view ω = 43 °, the projection lens having the configuration shown in FIG.
By satisfying the relationships (1) to (6), the back focus is long, the telecentricity is satisfied, and the distortion and the chromatic aberration of magnification are corrected.

Specific values are shown in the following (Table 6). Each symbol in the following (Table 6) is the same as in Example 1 above. Further, the aspherical shape is a rotationally symmetric aspherical surface represented by the above (Formula 1), where X is a displacement amount from the lens apex at the position of the radial distance h of the opening from the optical axis of the lens.

[0119]

[Table 6]         f0 = 10.7, aperture ratio 1: 3.0, ω = 43 °         fI / f0 = 624.8         fII / f0 = 2.27         ndII1-ndII2 = -0.00077         νdII1-νdII2 = 3.94         PgFII1-PgFII2 = -0.0173         fII12 / f0 = -2.41                         Axis between faces       Surface radius (mm) Direction distance (mm) Nd νd     r1 = 139.100 d1 = 3.0 n1 = 1.84666 ν1 = 23.83     r2 = 303.243 d2 = 0.5     r3 = 21.923 d3 = 1.5 n2 = 1.77250 ν2 = 49.62     r4 = 11.653 d4 = 5.0     r5 = 16.692 d5 = 1.5 n3 = 1.77250 ν3 = 49.62     r6 = 6.472 d6 = 5.0     r7 = -103.720 d7 = 2.0 n4 = 1.77250 ν4 = 49.62     r8 = 24.552 d8 = 0.2     r9 = 13.330 d9 = 8.8 n5 = 1.80518 ν5 = 25.46     r10 = -49.815 d10 = 1.7     r11 = 0.000 d11 = 2.6     r12 = 1231.765 d12 = 3.6 n6 = 1.56384 ν6 = 60.83     r13 = -8.721 d13 = 0.8 n7 = 1.80518 ν7 = 25.46     r14 = -20.264 d14 = 4.0     r15 = -79.223 d15 = 1.1 n8 = 1.74000 ν8 = 31.7     r16 = 13.016 d16 = 2.0 n9 = 1.74077 ν9 = 27.76     r17 = 25.725 d17 = 2.1     r18 = -3143.507 d18 = 3.3 n10 = 1.49700 ν10 = 81.5     r19 = -26.914 d19 = 0.1     r20 = -70.134 d20 = 3.8 n11 = 1.49700 ν11 = 81.5     r21 = -20.334 d21 = 0.1     r22 = 30.225 d22 = 5.5 n12 = 1.49700 ν12 = 81.5     r23 = -37.780 d23 = 12.0     r24 = 0.000 d24 = 24.0 n13 = 1.51680 ν13 = 64.2     r25 = 0.000 d25 = 0.2 The aspherical surface coefficient of each surface is shown below.

Aspherical surface coefficient A4 = 2.21607 × 10 ^-4 A6 = -4.26268 × 10 ^-7 A8 = 1.33169 × 10 ^-8 A10 = 0.0 Aspherical surface coefficient A4 = 5.56639 × 10 ^-5 A6 =- 1.53377 × 10 ^-6 A8 = 5.29892 × 10 ^-8 A10 = 0.0 FIGS. 12A, 12B, and 12C show the spherical aberration, astigmatism, and distortion of the projection lens of this example.

According to this embodiment, the I-th lens group GI
Is configured in the order of the positive meniscus lens I1, the negative meniscus lens I2, the negative meniscus lens I3, the biconcave lens I4, and the biconvex lens I5 from the screen side, by shortening the air gap between the final lens II5 and the prism III2, The whole lens system can be made compact as compared with the first embodiment, and the half angle of view ω = 43.
The wide back angle and telecentricity are satisfied while the angle is wide, and distortion and chromatic aberration of magnification are sufficiently corrected.

<Seventh Embodiment> Next, the seventh embodiment of the present invention will be described.
The projection lens of the embodiment will be described with reference to the drawings. FIG. 13 is an arrangement diagram showing the configuration of the projection lens in the present embodiment.

As shown in FIG. 13, the projection lens of the present embodiment is arranged such that the first lens group GI and the second lens group GI are arranged in order from the screen side (left side in FIG. 13) on a common optical axis.
The lens group GII.

The I-th lens group GI has a positive meniscus lens I1 having a convex surface facing the screen side, a negative meniscus lens I2 having a convex surface facing the screen side, and a convex surface facing the screen side, which are arranged in order from the screen side. A negative meniscus lens I3, a cemented lens of a positive meniscus lens I4 having a concave surface facing the screen side and a biconcave lens I5, and a positive meniscus lens I having a convex surface facing the screen side.
6 and a cemented lens of a biconvex lens I7 and a negative meniscus lens I8 having a concave surface facing the screen. The structure of the second lens group GII is the same as that of the first embodiment.

A diaphragm S is arranged between the positive meniscus lens I6 and the biconvex lens I7 in the I-th lens group GI.

Further, a spatial light modulation element III1 is arranged on the opposite screen side of the second lens group GII, and a prism III2 is arranged between the spatial light modulation element III1 and the lens group.

The projection lenses of the present embodiment also satisfy the above expressions (1) to (6).

The projection lens of this embodiment will be described below with reference to specific examples.

(Embodiment 7) In this embodiment, the F number F _NO
= 3.0, the focal length f = 10.7, and the half angle of view ω = 43 ° in the projection lens of the configuration shown in FIG.
By satisfying the relationships (1) to (6), the back focus is long, the telecentricity is satisfied, and the distortion and the chromatic aberration of magnification are corrected.

Specific values are shown in the following (Table 7). Each symbol in the following (Table 7) is the same as in Example 1 above. Further, the aspherical shape is a rotationally symmetric aspherical surface represented by the above (Formula 1), where X is a displacement amount from the lens apex at the position of the radial distance h of the opening from the optical axis of the lens.

[0131]

[Table 7]         f0 = 10.7, aperture ratio 1: 3.0, ω = 43 °         fI / f0 = -10.39         fII / f0 = 2.04         ndII1-ndII2 = -0.00077         νdII1-νdII2 = 3.94         PgFII1-PgFII2 = -0.0173       fII12 / f0 = -2.41                         Axis between faces       Surface radius (mm) Direction distance (mm) Nd νd     r1 = 82.150 d1 = 3.0 n1 = 1.75520 ν1 = 27.53     r2 = 109.876 d2 = 0.5     r3 = 18.687 d3 = 1.5 n2 = 1.66546 ν2 = 55.42     r4 = 9.395 d4 = 5.0     r5 = 15.447 d5 = 1.5 n3 = 1.66546 ν3 = 55.42     r6 = 6.655 d6 = 5.0     r7 = -165.259 d7 = 3.0 n4 = 1.66546 ν4 = 55.42     r8 = -14.000 d8 = 1.0 n5 = 1.49700 ν5 = 81.5     r9 = 14.502 d9 = 0.2     r10 = 13.198 d10 = 4.0 n6 = 1.80518 ν6 = 25.46     r11 = 780.636 d11 = 1.7     r12 = 0.000 d12 = 2.6     r13 = 1231.765 d13 = 3.6 n7 = 1.56384 ν7 = 60.83     r14 = -7.353 d14 = 0.8 n8 = 1.80518 ν8 = 25.46     r15 = -19.393 d15 = 4.0     r16 = -79.223 d16 = 1.1 n9 = 1.74000 ν9 = 31.7     r17 = 13.016 d17 = 2.0 n10 = 1.74077 ν10 = 27.76     r18 = 25.725 d18 = 2.1     r19 = -77.907 d19 = 3.3 n11 = 1.49700 ν11 = 81.5     r20 = -18.138 d20 = 0.1     r21 = -44.617 d21 = 3.8 n12 = 1.49700 ν12 = 81.5     r22 = -19.828 d22 = 0.1     r23 = 38.362 d23 = 5.5 n13 = 1.49700 ν13 = 81.5     r24 = -25.086 d24 = 12.0     r25 = 0.000 d25 = 24.0 n14 = 1.51680 ν14 = 64.2     r26 = 0.000 d26 = 0.2 The aspherical surface coefficient of each surface is shown below.

Aspherical coefficient of five surfaces A4 = 1.49605 × 10 ^-4 A6 = 2.08972 × 10 ^-7 A8 = 1.32888 × 10 ^-9 A10 = 0.0 Seven surface aspherical coefficient A4 = 1.10476 × 10 ^-4 A6 = -6.80057 × 10 ^-7 A8 = 7.57282 × 10 ^-8 A10 = 0.0 FIGS. 14A, 14B, and 14C show the spherical aberration, astigmatism, and distortion of the projection lens of this example.

According to this embodiment, the I-th lens group GI
Is arranged in order of the positive meniscus lens I1, the negative meniscus lens I2, and the negative meniscus lens I3 from the screen side, and since the positive meniscus lens I4 and the biconcave lens I5 are cemented, it is easy to correct the chromatic aberration of magnification, and A wide back angle of ω = 43 ° is satisfied, a long back focus and telecentricity are satisfied, and distortion and chromatic aberration of magnification are sufficiently corrected.

<Eighth Embodiment> Next, the eighth embodiment of the present invention will be described.
The projection lens of the embodiment will be described with reference to the drawings. FIG. 15 is a layout diagram showing the configuration of the projection lens in the present embodiment.

As shown in FIG. 15, the projection lens of the present embodiment has the I-th lens group GI and the II-th lens group GI arranged in order from the screen side (the left side in FIG. 15) on the common optical axis.
The lens group GII.

The I-th lens group GI includes, in order from the screen side, a cemented lens of a negative meniscus lens I1 having a convex surface facing the screen side and a positive meniscus lens I2 having a convex surface facing the screen side, and a cemented lens on the screen side. A negative meniscus lens I3 having a convex surface, a negative meniscus lens I4 having a convex surface facing the screen, a cemented lens of a positive meniscus lens I5 having a concave surface facing the screen and a biconcave lens I6, a biconvex lens I7, and a biconvex lens I7. It is composed of a convex lens I8 and a cemented lens of a negative meniscus lens I9 having a concave surface facing the screen. The structure of the second lens group GII is the same as that of the first embodiment.

The biconvex lens I in the I-th lens group GI
A diaphragm S is arranged between the lens 7 and the biconvex lens I8.

Further, a spatial light modulation element III1 is arranged on the opposite screen side of the second lens group GII, and a prism III2 is arranged between the spatial light modulation element III1 and the lens group.

The projection lenses of the present embodiment also satisfy the above expressions (1) to (6).

The projection lens of this embodiment will be described below with reference to specific examples.

(Embodiment 8) In this embodiment, the F number F _NO
= 3.0, the focal length f = 10.7, and the half angle of view ω = 43 ° in the projection lens of the configuration shown in FIG.
By satisfying the relationships (1) to (6), the back focus is long, the telecentricity is satisfied, and the distortion and the chromatic aberration of magnification are corrected.

Specific values are shown in the following (Table 8). Each symbol in the following (Table 8) is the same as in the case of Example 1 above. Further, the aspherical shape is a rotationally symmetric aspherical surface represented by the above (Formula 1), where X is a displacement amount from the lens apex at the position of the radial distance h of the opening from the optical axis of the lens.

[0143]

[Table 8]         f0 = 10.7, aperture ratio 1: 3.0, ω = 43 °         fI / f0 = -24.0         fII / f0 = 2.09         ndII1-ndII2 = -0.00077         νdII1-νdII2 = 3.94         PgFII1-PgFII2 = -0.0173         fII12 / f0 = -2.31                         Axis between faces       Surface radius (mm) Direction distance (mm) Nd νd     r1 = 81.640 d1 = 2.0 n1 = 1.78472 ν1 = 25.72     r2 = 35.000 d2 = 3.5 n2 = 1.75520 ν2 = 27.53     r3 = 166.278 d3 = 0.5     r4 = 35.146 d4 = 1.5 n3 = 1.66546 ν3 = 55.42     r5 = 9.742 d5 = 5.0     r6 = 11.139 d6 = 1.5 n4 = 1.66546 ν4 = 55.42     r7 = 6.194 d7 = 5.0     r8 = -273.664 d8 = 3.0 n5 = 1.66546 ν5 = 55.42     r9 = -20.000 d9 = 1.0 n6 = 1.49700 ν6 = 81.5     r10 = 17.059 d10 = 0.2     r11 = 13.603 d11 = 4.0 n7 = 1.80518 ν7 = 25.46     r12 = -331.765 d12 = 1.7     r13 = 0.000 d13 = 2.6     r14 = 1231.765 d14 = 3.6 n8 = 1.56384 ν8 = 60.83     r15 = -7.080 d15 = 0.8 n9 = 1.80518 ν9 = 25.46     r16 = -19.393 d16 = 4.0     r17 = -79.223 d17 = 1.1 n10 = 1.74000 ν10 = 31.7     r18 = 13.016 d18 = 2.0 n11 = 1.74077 ν11 = 27.76     r19 = 25.725 d19 = 2.1     r20 = -48.017 d20 = 3.3 n12 = 1.49700 ν12 = 81.5     r21 = -17.261 d21 = 0.1     r22 = -40.555 d22 = 3.8 n13 = 1.49700 ν13 = 81.5     r23 = -18.984 d23 = 0.1     r24 = 36.923 d24 = 5.5 n14 = 1.49700 ν14 = 81.5     r25 = -25.660 d25 = 12.0     r26 = 0.000 d26 = 24.0 n15 = 1.51680 ν15 = 64.2     r27 = 0.000 d27 = 0.2 The aspherical surface coefficient of each surface is shown below.

Aspherical coefficient of 6 surfaces A4 = 2.11156 × 10 ^-4 A6 = 4.35104 × 10 ^-8 A8 = 3.08002 × 10 ^-8 A10 = 0.0 Aspherical coefficient of 8 surfaces A4 = 9.97150 × 10 ^-5 A6 = -1.25920 × 10 ^-6 A8 = 1.21330 × 10 ^-7 A10 = 0.0 FIGS. 16A, 16B, and 16C show the spherical aberration, astigmatism, and distortion of the projection lens of this example.

According to this embodiment, the I-th lens group GI
Are arranged in that order from the screen side, the negative meniscus lens I1, the positive meniscus lens I2, the negative meniscus lens I3, and the negative meniscus lens I4.
And the positive meniscus lens I2 are cemented together, and the positive meniscus lens I5 and the biconcave lens I6 are cemented together,
It is easy to correct chromatic aberration of magnification and the half angle of view ω = 4
Despite the wide angle of 3 °, a long back focus and telecentricity are satisfied, and distortion and chromatic aberration of magnification are sufficiently corrected.

<Ninth Embodiment> FIG. 17 is a layout showing the structure of an image magnifying and projecting system according to a ninth embodiment of the present invention. As shown in FIG. 17, the image magnifying and projecting system according to the present embodiment includes a light source C, a spatial light modulator B that is illuminated by light emitted from the light source C, and forms an optical image, and a spatial light modulator. It is composed of a projection lens A for projecting an optical image on the element B. Here, as the projection lens A, the projection lens described in the first to eighth embodiments is used. Incidentally, FIG.
7, P is a focus plane of an image projected by the image magnifying and projecting system.

According to the image magnifying and projecting system of this embodiment, the optical image formed on the spatial light modulator B illuminated by the light source C can be magnified and projected on the focus plane P by the projection lens A. In this case, since the projection lens described in the first to eighth embodiments is used as the projection lens A, it is possible to realize a compact image magnifying projection system with a short projection distance.

<Tenth Embodiment> FIG. 18 is a layout showing the structure of a video projector according to the tenth embodiment of the present invention. As shown in FIG. 18, the video projector according to the present embodiment includes light sources C and R,
A means D for temporally limiting the light from the light source C to three colors of blue, green and red by rotating the G and B filters.
And a spatial light modulation element B which is illuminated by the light emitted from the light source C and forms an optical image corresponding to the three colors of blue, green, and red that change with time, and the spatial light modulation element B on the spatial light modulation element B. It is composed of a projection lens A for projecting an optical image. Here, as the projection lens A, the projection lens described in the first to eighth embodiments is used.

According to the video projector of this embodiment, the light from the light source C is temporally limited to the three colors of blue, green and red by the means D for temporally limiting the three colors of blue, green and red. It is disassembled and the spatial light modulator B is illuminated. Three types of optical images of blue, green, and red are temporally divided and formed on the spatial light modulator B, and enlarged and projected by the projection lens A. In this case, since the projection lens described in the first to eighth embodiments is used as the projection lens A, a bright image with less color bleeding and distortion can be obtained.
Since the projection distance is short, it is possible to realize a video projector that can be used in a narrow space.

<Eleventh Embodiment> FIG. 19 is a layout showing the structure of a rear projector according to an eleventh embodiment of the present invention. As shown in FIG. 19, the rear projector in the present embodiment is a video projector G, a mirror H that bends the light projected from the projection lens in the video projector G, and a transmissive type that further projects the projected light as an image. And a screen I. Here, as the video projector G, the video projector described in the tenth embodiment is used. In addition, in FIG. 19, J is a housing for housing the rear projector.

According to the rear projector of this embodiment, the image projected from the video projector G is reflected by the mirror H and focused on the transmissive screen I. In this case, as the video projector G, the first
Since the video projector described in the No. 0 embodiment is used, the depth and height of the set can be suppressed small, and a compact set can be realized.

<Twelfth Embodiment> FIG. 20 is a block diagram of a multivision system according to a twelfth embodiment of the present invention. As shown in FIG. 20, the multi-vision system according to the present embodiment includes a plurality of systems including a video projector G and a transmissive screen I for projecting light projected from a projection lens in the video projector G as an image, The image division circuit L divides an image. Here, as the video projector G, the video projector described in the tenth embodiment is used. In addition, in FIG.
K is a housing that houses each system.

According to the multivision system of the present embodiment, the video signal is processed and divided by the video division circuit L and sent to the plurality of video projectors G. The image projected from the video projector G is formed on the transmissive screen I. In this case, since the video projector described in the tenth embodiment is used as the video projector G, it is possible to realize a compact set having a short depth.

In the above embodiment, the half angle of view ω
Of 43 ° and the F number F _NO of 3.0 has been described as an example, but the present invention is not necessarily limited to the projection lens having this configuration. It is preferable that the half angle of view ω is 40 ° or more and the F number F _NO is 3.0 or less. When the F number F _NO is 3.0 or less, when a liquid crystal panel or a reflective mirror device is used as the spatial light modulation element, it is possible to obtain a maximum bright system without a decrease in contrast. When the angle of view ω is 40 ° or more, the distance projected on the screen can be further shortened, and the rear projection television can be made compact.

[0155]

As described above, according to the present invention,
By properly setting the lens configuration, the projection distance is short and compact, but the back focus is long,
It is possible to provide a projection lens that satisfies the telecentricity, has less color bleeding, and can realize an image with less distortion. Further, according to the present invention, by using such a projection lens, it is possible to provide an image magnifying projection system, a video projector, a rear projector, and a multivision system that can realize a bright and high-quality large screen image in a compact manner. it can.

[Brief description of drawings]

FIG. 1 is a layout diagram showing a configuration of a projection lens according to a first embodiment of the present invention.

2A is a spherical aberration diagram of the projection lens in Embodiment 1 of the present invention, FIG. 2B is an astigmatism diagram of the projection lens, FIG.
(C) is a distortion diagram of the projection lens.

FIG. 3 is a layout diagram showing a configuration of a projection lens according to a second embodiment of the present invention.

4A is a spherical aberration diagram of the projection lens in Embodiment 2 of the present invention, FIG. 4B is an astigmatism diagram of the projection lens, FIG.
(C) is a distortion diagram of the projection lens.

FIG. 5 is a layout diagram showing a configuration of a projection lens according to a third embodiment of the present invention.

6A is a spherical aberration diagram of the projection lens in Embodiment 3 of the present invention, FIG. 6B is an astigmatism diagram of the projection lens, FIG.
(C) is a distortion diagram of the projection lens.

FIG. 7 is an arrangement diagram showing a configuration of a projection lens according to a fourth embodiment of the present invention.

8A is a spherical aberration diagram of the projection lens in Embodiment 4 of the present invention, FIG. 8B is an astigmatism diagram of the projection lens, FIG.
(C) is a distortion diagram of the projection lens.

FIG. 9 is an arrangement diagram showing a configuration of a projection lens according to a fifth embodiment of the present invention.

10A is a spherical aberration diagram of the projection lens in Embodiment 5 of the present invention, FIG. 10B is an astigmatism diagram of the projection lens, and FIG. 10C is a distortion diagram of the projection lens.

FIG. 11 is a layout diagram showing a configuration of a projection lens according to a sixth embodiment of the present invention.

12A is a spherical aberration diagram of the projection lens in Embodiment 6 of the present invention, FIG. 12B is an astigmatism diagram of the projection lens, and FIG. 12C is a distortion diagram of the projection lens.

FIG. 13 is a layout diagram showing a configuration of a projection lens according to a seventh embodiment of the present invention.

14A is a spherical aberration diagram of the projection lens in Embodiment 7 of the present invention, FIG. 14B is an astigmatism diagram of the projection lens,
(C) is a distortion diagram of the projection lens.

FIG. 15 is a layout diagram showing a configuration of a projection lens according to an eighth embodiment of the present invention.

16A is a spherical aberration diagram of the projection lens in Example 8 of the present invention, FIG. 16B is an astigmatism diagram of the projection lens, FIG.
(C) is a distortion diagram of the projection lens.

FIG. 17 is a layout diagram showing a configuration of an image enlargement / projection system according to a ninth embodiment of the present invention.

FIG. 18 is a layout diagram showing a configuration of a video projector according to a tenth embodiment of the invention.

FIG. 19 is a layout diagram showing a configuration of a rear projector according to an eleventh embodiment of the present invention.

FIG. 20 is a configuration diagram of a multivision system according to a twelfth embodiment of the present invention.

[Explanation of symbols]

GI First lens group GI GII Second lens group S Aperture III1 Spatial light modulation element III2 Prism A Projection lens B Spatial modulation element C Light source D Means for temporally limiting light from the light source into three colors of blue, green and red G video projector H mirror I transmissive screen J case K case L image division circuit P focus plane of projected image

Claims (13)

(57) [Claims] 1. A projection lens comprising an I-th lens group arranged in order from the screen side and a II-lens group having a positive power, wherein the I-lens group is arranged in order from the screen side. In addition, a positive meniscus lens having a convex surface facing the screen side, a first negative meniscus lens having a convex surface facing the screen side, a second negative meniscus lens having a convex surface facing the screen side, and a surface having a small radius of curvature are provided. A biconcave lens directed toward the screen side, a biconvex lens, and a biconvex lens, wherein the second lens group is arranged in order from the screen side;
A convex lens, and a diaphragm is provided in the I-th lens group. The focal length of the entire projection lens system is f0, the focal length of the I-th lens group is fI, and the focal length of the II-lens group is fII, the refractive index of the lens of the second lens group closer to the screen of the cemented concave lens is ndII1, the refractive index of the lens of the second lens group farther from the screen of the cemented concave lens is ndII2, the second lens The Abbe number of the lens closer to the screen of the cemented concave lens of the group is νdII1, the Abbe number of the lens of the lens distant from the screen of the cemented concave lens of the II lens group is νdII2, and the Abbe number of the cemented concave lens of the II lens group is PgFII is the partial dispersion ratio (ng-nF) / (nF-nC) for g-line and F-line of the lens closer to the screen.
1. The partial dispersion ratio (ng-nF) / (nF-nC) of the lens farther from the screen of the cemented concave lens of the second lens group PgFII2, the cemented lens of the second lens group The focal length of the concave lens is fII
A projection lens satisfying the following formulas (1) to (6) when the number is 12. (1) 2.5 <| fI / f0 | (2) 1.8 <fII / f0 <4.5 (3) | ndII1-ndII2 | <0.001 (4) | νdII1-νdII2 | <5 (5 ) 0.01 <| PgFII1-PgFII2 | (6) -5 <fII12 / f0 <-1.8 2. A projection lens comprising an I-th lens group arranged in order from the screen side and a II-lens group having positive power, wherein the I-lens group is arranged in order from the screen side. Also, a first negative meniscus lens having a convex surface facing the screen side, a biconvex lens, a second negative meniscus lens having a convex surface facing the screen side, a positive meniscus lens having a concave surface facing the screen side, and a biconcave lens. And the second lens group has a cemented concave lens and at least two convex lenses, which are sequentially arranged from the screen side. A diaphragm is provided in the first lens group, and the entire projection lens system is provided. F0, the focal length of the I-th lens group is fI, the focal length of the II-th lens group is fII, and the focal length of the second-lens group closer to the screen of the cemented concave lens. The refractive index of the lens is ndII1, the refractive index of the lens of the second lens group farther from the screen of the cemented concave lens is ndII2, and the Abbe number of the lens of the second lens group closer to the screen of the cemented concave lens is νdII1. , The Abbe number of the lens farther from the screen of the cemented concave lens of the second lens group is ν
dII2, the partial dispersion ratio (ng-nF) / (nF-nC) of the lens closer to the screen of the cemented concave lens of the second lens group to (g-nF) / (nF-nC) is PgFII1,
The partial dispersion ratio (n to the g-line and F-line of the lens farther from the screen of the cemented concave lens of the second lens group (n)
g-nF) / (nF-nC) as PgFII2,
The focal length of the cemented concave lens of the I lens group is fII12.
The projection lens is characterized by satisfying the following expressions (1) to (6). (1) 2.5 <| fI / f0 | (2) 1.8 <fII / f0 <4.5 (3) | ndII1-ndII2 | <0.001 (4) | νdII1-νdII2 | <5 (5 ) 0.01 <| PgFII1-PgFII2 | (6) -5 <fII12 / f0 <-1.8 3. A projection lens comprising an I-th lens group arranged in order from the screen side and a II-lens group having a positive power, wherein the I-lens group is arranged in order from the screen side. Further, it has a first negative meniscus lens having a convex surface facing the screen side, a biconvex lens, a second negative meniscus lens having a convex surface facing the screen side, and a cemented lens of a biconcave lens and a biconvex lens, Said I
The I lens group has a cemented concave lens and at least two convex lenses, which are sequentially arranged from the screen side, a diaphragm is provided in the I lens group, and the focal length of the entire projection lens system is f0. The focal length of the I-th lens group is fI, the focal length of the II-th lens group is fII, the refractive index of the lens closer to the screen of the cemented concave lens of the II-lens group is ndII1, and the refractive index of the II-lens group is The refractive index of the lens farther from the screen of the cemented concave lens is n
dII2, the Abbe number of the lens of the second lens group closer to the screen of the cemented concave lens is νdII1, the Abbe number of the lens of the second lens group distant from the screen of the cemented concave lens is νdII2, the II lens Partial dispersion ratio (ng-nF) / g line and F line of the lens closer to the screen of the cemented concave lens of the group
(NF-nC) is PgFII1, g of the lens farther from the screen of the cemented concave lens of the II lens group.
Partial dispersion ratio (ng-nF) / (nF-
nC) is PgFII2, and the focal length of the cemented concave lens of the II-th lens group is fII12, a projection lens satisfying the following expressions (1) to (6). (1) 2.5 <| fI / f0 | (2) 1.8 <fII / f0 <4.5 (3) | ndII1-ndII2 | <0.001 (4) | νdII1-νdII2 | <5 (5 ) 0.01 <| PgFII1-PgFII2 | (6) -5 <fII12 / f0 <-1.8 4. A projection lens comprising an I-th lens group arranged in order from the screen side and a II-lens group having a positive power, wherein the I-lens group is arranged in order from the screen side. Further, a negative meniscus lens having a convex surface facing the screen side, a cemented lens of a first positive meniscus lens having a concave surface facing the screen side and a biconcave lens, and a second positive meniscus lens having a convex surface facing the screen side , A biconvex lens, and the second lens group is
It has a cemented concave lens and at least two convex lenses arranged in order from the screen side, a diaphragm is provided in the I-th lens group, and the focal length of the entire projection lens system is f0,
The focal length of the I-th lens group is fI, the focal length of the II-th lens group is fII, and the refractive index of the lens closer to the screen of the cemented concave lens of the II-th lens group is nd.
II1, the refractive index of the lens farther from the screen of the cemented concave lens of the II lens group is ndII2, the Abbe number of the lens of the lens closer to the screen of the cemented concave lens of the II lens group is νdII1, the II lens The Abbe number of the lens farther from the screen of the cemented concave lens in the group is νdII2, and the partial dispersion ratio (ng-nF) / g line and F line of the lens closer to the screen of the cemented concave lens in the II lens group is (ng-nF) / (NF-nC) is PgFII1, and the partial dispersion ratio (ng-nF) / (nF-nC) for the g line and the F line of the lens farther from the screen of the cemented concave lens of the II lens group is PgFI.
I2, a projection lens satisfying the following expressions (1) to (6), where fII12 is the focal length of the cemented concave lens of the second lens group. (1) 2.5 <| fI / f0 | (2) 1.8 <fII / f0 <4.5 (3) | ndII1-ndII2 | <0.001 (4) | νdII1-νdII2 | <5 (5 ) 0.01 <| PgFII1-PgFII2 | (6) -5 <fII12 / f0 <-1.8 5. A projection lens comprising an I lens group arranged in order from the screen side and a II lens group having a positive power, wherein the I lens group is arranged in order from the screen side. Also, a first negative meniscus lens having a convex surface facing the screen side, a cemented lens of a positive meniscus lens having a concave surface facing the screen side and a biconcave lens, and a second negative meniscus lens having a concave surface facing the screen side. A cemented lens with a meniscus lens and a biconvex lens, and the second lens group II has a cemented concave lens element and at least two convex lens elements arranged in order from the screen side. Is provided with a diaphragm, the focal length of the entire projection lens system is f0, the focal length of the I-th lens group is fI, the focal length of the II-lens group is fII, and the focal length of the II-lens group is in front. The refractive index of the lens closer to the screen of the cemented concave lens is ndII1, the refractive index of the lens farther from the screen of the cemented concave lens of the II lens group is ndII2, and the refractive index of the cemented concave lens screen of the II lens group is The Abbe number of the closer lens is ν
dII1, the Abbe number of the lens farther from the screen of the cemented concave lens of the second lens group is νdII2,
The partial dispersion ratio (ng) of the lens closer to the screen of the cemented concave lens of the second lens group to the g line and the F line (ng
-NF) / (nF-nC) as PgFII1,
Partial dispersion ratio (ng-nF) for g-line and F-line of the lens farther from the screen of the cemented concave lens of the lens group
A projection lens satisfying the following expressions (1) to (6), where / (nF-nC) is PgFII2 and the focal length of the cemented concave lens of the second lens group is fII12. (1) 2.5 <| fI / f0 | (2) 1.8 <fII / f0 <4.5 (3) | ndII1-ndII2 | <0.001 (4) | νdII1-νdII2 | <5 (5 ) 0.01 <| PgFII1-PgFII2 | (6) -5 <fII12 / f0 <-1.8 6. A projection lens comprising an I lens group arranged in order from the screen side and a II lens group having positive power, wherein the I lens group is arranged in order from the screen side. A positive meniscus lens having a convex surface facing the screen side, a first negative meniscus lens having a convex surface facing the screen side, a second negative meniscus lens having a convex surface facing the screen side, a biconcave lens, and a biconvex lens. And the second lens group has a cemented concave lens and at least two convex lenses, which are sequentially arranged from the screen side. A diaphragm is provided in the first lens group, and the entire projection lens system is provided. F0, the focal length of the I-th lens group is fI, the focal length of the II-th lens group is fII, and the focal length of the second-lens group closer to the screen of the cemented concave lens. The refractive index of the lens is ndII1, the refractive index of the lens of the second lens group farther from the screen of the cemented concave lens is ndII2, and the Abbe number of the lens of the second lens group closer to the screen of the cemented concave lens is νdII1. , The Abbe number of the lens farther from the screen of the cemented concave lens of the second lens group is ν
dII2, the partial dispersion ratio (ng-nF) / (nF-nC) of the lens closer to the screen of the cemented concave lens of the second lens group to (g-nF) / (nF-nC) is PgFII1,
The partial dispersion ratio (n to the g-line and F-line of the lens farther from the screen of the cemented concave lens of the second lens group (n)
g-nF) / (nF-nC) as PgFII2,
The focal length of the cemented concave lens of the I lens group is fII12.
The projection lens is characterized by satisfying the following expressions (1) to (6). (1) 2.5 <| fI / f0 | (2) 1.8 <fII / f0 <4.5 (3) | ndII1-ndII2 | <0.001 (4) | νdII1-νdII2 | <5 (5 ) 0.01 <| PgFII1-PgFII2 | (6) -5 <fII12 / f0 <-1.8 7. A projection lens comprising an I lens group arranged in order from the screen side and a II lens group having positive power, wherein the I lens group is arranged in order from the screen side. In addition, a first positive meniscus lens having a convex surface facing the screen side, a first negative meniscus lens having a convex surface facing the screen side, a second negative meniscus lens having a convex surface facing the screen side, and a screen side It has a cemented lens of a second positive meniscus lens having a concave surface and a biconcave lens, and a third positive meniscus lens having a convex surface facing the screen side, and the second lens group is arranged in order from the screen side. Further, it has a cemented concave lens and at least two convex lenses, a diaphragm is provided in the I-th lens group, the focal length of the entire projection lens system is f0, and the focal length of the I-th lens group is The point distance is fI, the focal length of the second lens group is fII, and the refractive index of the lens of the second lens group closer to the screen of the cemented concave lens is ndI.
I1, the refractive index of the lens farther from the screen of the cemented concave lens of the II lens group is ndII2, the Abbe number of the lens of the lens closer to the screen of the cemented concave lens of the II lens group is νdII1, the II lens The Abbe number of the lens farther from the screen of the cemented concave lens in the group is νdII2, and the partial dispersion ratio (ng-nF) / g line and F line of the lens closer to the screen of the cemented concave lens in the II lens group is (ng-nF) / (NF-nC) as P
gFII1, the partial dispersion ratio (ng-nF) / (nF-nC) of the lens farther from the screen of the cemented concave lens of the second lens group to the g-line and the F-line is PgFII
2. When the focal length of the cemented concave lens of the second lens group II is fII12, a projection lens satisfying the following expressions (1) to (6). (1) 2.5 <| fI / f0 | (2) 1.8 <fII / f0 <4.5 (3) | ndII1-ndII2 | <0.001 (4) | νdII1-νdII2 | <5 (5 ) 0.01 <| PgFII1-PgFII2 | (6) -5 <fII12 / f0 <-1.8 8. A projection lens comprising an I lens group arranged in order from the screen side and a II lens group having a positive power, wherein the I lens group is arranged in order from the screen side. Also, a cemented lens of a first negative meniscus lens having a convex surface facing the screen side and a first positive meniscus lens having a convex surface facing the screen side, a second negative meniscus lens having a convex surface facing the screen side, The third negative meniscus lens having a convex surface on the screen side, a cemented lens of a second positive meniscus lens having a concave surface on the screen side and a biconcave lens, and a biconvex lens, wherein the second lens group is , A cemented concave lens and at least two convex lenses, which are sequentially arranged from the screen side, a diaphragm is provided in the I-th lens group, and the focal length of the entire projection lens system is f0, the focal length of the I-th lens group is fI, the focal length of the II-th lens group is fII, the refractive index of the lens closer to the screen of the cemented concave lens of the II-lens group is ndII1, the II-th lens The refractive index of the lens farther from the screen of the cemented concave lens in the group is ndII2, and the Abbe number of the lens closer to the screen of the cemented concave lens in the second lens group is ν
dII1, the Abbe number of the lens farther from the screen of the cemented concave lens of the second lens group is νdII2,
The partial dispersion ratio (ng) of the lens closer to the screen of the cemented concave lens of the second lens group to the g line and the F line (ng
-NF) / (nF-nC) as PgFII1,
Partial dispersion ratio (ng-nF) for g-line and F-line of the lens farther from the screen of the cemented concave lens of the lens group
A projection lens satisfying the following expressions (1) to (6), where / (nF-nC) is PgFII2 and the focal length of the cemented concave lens of the second lens group is fII12. (1) 2.5 <| fI / f0 | (2) 1.8 <fII / f0 <4.5 (3) | ndII1-ndII2 | <0.001 (4) | νdII1-νdII2 | <5 (5 ) 0.01 <| PgFII1-PgFII2 | (6) -5 <fII12 / f0 <-1.8 9. The projection lens according to any one of claims 1-8 having an aspheric surface at least two surfaces. 10. A light source, a spatial light modulation element that is illuminated by light emitted from the light source and forms an optical image, and projection means that projects the optical image on the spatial light modulation element. image enlargement projection system using a projection lens according to any one of claims 1 to 9 as a projection means. 11. A light source, a means for temporally limiting the light from the light source to three colors of blue, green and red, and blue which is illuminated by the light emitted from the light source and which temporally changes,
10. A spatial light modulation element for forming optical images corresponding to three colors of green and red, and a projection means for projecting an optical image on the spatial light modulation element, the projection means being any one of claims 1 to 10 . A video projector using the projection lens described in. 12. A rear projector comprising: a video projector, a mirror that bends light projected from projection means in the video projector, and a transmissive screen that projects the projected light as an image. A rear projector using the video projector according to claim 11 as the video projector. 13. A multi-system comprising a plurality of systems comprising a video projector and a transmissive screen for projecting light projected from projection means in the video projector as an image, and an image dividing circuit for dividing the image. A vision system, wherein the video projector according to claim 11 is used as the video projector.