JP2010169798A5 - - Google Patents

Description

The present invention relates primarily to the image screen other zoom lens lens aperture is less for enlarging and projecting from the light valve for forming an image by changing the reflecting direction of the light, such as DMD.

Thus, by mounting the zoom lens of the present invention on a projector device, the entire device can be reduced in size (claim 6), and a thin projector device that is convenient for carrying can be provided.

1 is a configuration diagram showing a lens configuration of a first example of a zoom lens according to the present invention. FIG. It is an aberration diagram showing various aberrations of the lens of the first example. It is a block diagram which showed the lens structure of 2nd Example of the zoom lens of this invention. It is an aberration diagram showing various aberrations of the lens of the second example. It is a block diagram which showed the lens structure of 3rd Example of the zoom lens of this invention. It is an aberration diagram showing various aberrations of the lens of the third example.

Hereinafter, the present invention will be described with respect to specific numerical examples. In the zoom lenses of the following first to third embodiments, in order from the magnification side, the first lens group LG1 having a negative refractive power as a whole, the second lens group LG2 having a negative refractive power as a whole, and the whole as a whole. The first lens group LG1 includes a third lens group LG3 having a positive refractive power. The first lens group LG1 is a lens having a negative meniscus shape convex to the enlargement side in order from the enlargement side (lens name L11, enlargement side surface). 101, reduction side surface 102) (hereinafter negative lens), negative lens (lens name L12, enlargement side surface 103, reduction side surface 104), lens having positive refractive power (lens name L13, enlargement side surface 105, reduction side surface 106) (hereinafter referred to as “lens side L”). A positive lens), a negative lens (lens name L14, enlargement side 107, reduction side 108), and a positive lens (lens name L15, enlargement side 108, reduction side 109). The second lens group LG2 is composed of five lenses including three positive lenses and two negative lenses (lens names L21, L22,... The third lens group LG3 is composed of a single positive lens (lens name is L31, enlargement side name is 301, reduction). The name of the side surface is 302). A cover glass CG (C01 is an enlarged side surface and C02 is a reduced side surface) which is a component of a light valve such as a DMD with a slight air gap between the reduced side of the third lens group LG3 and the light valve surface. ) Is arranged. The third lens group LG3 is fixed during zooming operation, and the first lens group LG1 is enlarged from the wide-angle end to the intermediate area from the enlargement side to the reduction side, and from the intermediate area to the telephoto end is enlarged from the reduction side. The second lens unit LG2 moves on the optical axis in the lateral direction, and the entire lens system is zoomed by moving on the optical axis from the reduction side to the enlargement side from the wide-angle end to the telephoto end.

[Example 1]
Table 1 shows numerical examples of the first embodiment of the zoom lens of the present invention. FIG. 1 is a diagram showing the lens configuration, and FIG. 2 is a diagram showing various aberrations thereof. In the table and drawings, f is the focal length of the zoom lens system, F _no is the F-number, 2 [omega a total angle of view of the zoom lens. In addition, r is a radius of curvature, d is a lens thickness or a lens interval, n _d is a refractive index with respect to the d line, and ν _d is an Abbe number of the d line (however, the numerical value that changes due to the focusing operation in the table is 101 plane) The numerical value in the in-focus state with the object distance from 1700 mm). CA1, CA2, and CA3 in the spherical aberration diagrams in the various aberration diagrams are aberration curves at wavelengths of CA1 = 550.0 nm, CA2 = 450.0 nm, and CA3 = 620.0 nm, respectively. In the astigmatism diagram, S indicates sagittal and M indicates meridional. In addition, unless otherwise specified throughout, the wavelength used for calculation of various values is CA1 = 550.0 nm.

[Example 2]
Table 2 shows the numerical example will be given of a second embodiment of a zoom lens of the present invention. FIG. 3 is a diagram showing the lens configuration, and FIG. 4 is a diagram showing various aberrations thereof.

[Example 3]
Table 3 shows the numerical examples of the third embodiment of the zoom lens of the present invention. FIG. 5 is a diagram showing the lens configuration, and FIG. 6 is a diagram showing various aberrations.

Claims (6)

The first lens group having a negative refractive power as a whole, the second lens group having a positive refractive power as a whole, and the third lens group having a positive refractive power as a whole in order from the magnification side, The lens group is composed of, in order from the magnifying side, five lenses: a meniscus lens convex on the magnifying side, a negative lens, a lens having a positive refracting power, a negative lens, and a positive lens. The second lens group includes a positive lens, a negative meniscus lens convex to the enlargement side, a positive lens, a negative lens, and a positive lens in order from the enlargement side, and the third lens. The group is a zoom lens capable of zooming comprising a single positive lens, and the third lens group is fixed during zooming operation, and the first lens group extends from the wide-angle end to an intermediate region. Up to the zoom-out side, and from the middle to the telephoto end Over the optical axis in the direction from the reduction side to the enlargement side, and the second lens group moves on the optical axis in the direction from the reduction side to the enlargement side from the wide-angle end to the telephoto end. The following conditional expression (1) is satisfied with respect to the distance on the optical axis from the magnifying side surface of the lens arranged closest to the magnifying side in the first lens group at the wide angle end to the in-focus position, and The following conditional expression (2) is satisfied with respect to the positional relationship between the second lens group and the third lens group at the end, and the following conditional expression (3) is satisfied with respect to the magnification at the wide angle end of the second lens group. The power of the first lens group satisfies the following conditional expression (4), and the magnification of the second lens group at the telephoto end satisfies the following conditional expression (5). zoom lens that.
(1) 7.0 <TL / _fw <10.0
(2) 1.8 < _dIIw / _fw <2.5
(3) −1.2 <m _{II w} <−0.5
_{(4) -1.0 <f w /} f I <-0.5
(5) 1.4 <m _{II T} / m _{II w} <2.8
However,
TL: Distance on the optical axis from the magnifying side surface of the lens arranged closest to the magnifying side in the first lens unit at the wide angle end to the in-focus position (according to the magnifying side object distance of 1700 mm from the magnifying side most of the first lens unit) Out of focus)
f _w : Combined focal length of the entire lens system at the wide-angle end (focused state on the enlargement side object distance of 1700 mm from the most enlargement side surface of the first lens group)
d _{II w} : Air distance between the second lens group and the third lens group at the wide angle end f _I : Composite focal length m _{II w} of the first lens group m 2 _T : Magnification m _{II T} of the second lens group at the wide angle end Magnification of the second lens group at the end Regard the dimensions of the optical axis of the first lens group, and satisfies the following conditional expression (6), satisfying the following conditional expression (7) with respect to a power of the lens element which is disposed outermost on the magnifying side of the first lens group The following conditional expression (8) is satisfied with respect to the shape of the reduction side surface of the lens arranged closest to the magnification side in the first lens group, and is used for each lens constituting the first lens group. The zoom lens according to claim 1, wherein the following conditional expression (9) is satisfied with respect to dispersion characteristics of the glass material.
_{(6) 1.4 <L I /} f w <2.7
_{(7) -0.8 <f w /} f 1 <-0.2
(8) 0.8 <f _w / r ₂ <1.6
(9) 16 <(V ₁ + V ₂ + V ₄ ) / 3- (V ₃ + V ₅ ) / 2
However,
L _I : Distance f ₁ on the optical axis between the enlargement side surface of the lens arranged closest to the enlargement side in the first lens group and the reduction side surface of the lens arranged closest to the reduction side in the first lens group f ₁ : first lens group The focal length r _{2 of} the lens arranged closest to the magnification side: radius of curvature V ₁ of the reduction side of the lens arranged closest to the magnification side in the first lens group V ₁ : negative arranged closest to the magnification side in the first lens group Lens Abbe number V ₂ : Abbe number of the negative lens disposed on the second lens from the magnification side in the first lens group V ₃ : Abbe number of the positive lens disposed on the third lens from the magnification side in the first lens group V ₄ : Abbe number of the negative lens disposed on the fourth lens from the magnification side in the first lens group V ₅ : Abbe number of the positive lens disposed on the most reduction side in the first lens group The focusing operation is achieved by moving the first lens group in the optical axis direction, and conditional expression (10) is satisfied for the second lens in the first lens group constituting the first lens group. 3. The zoom lens according to claim 1, wherein the zoom lens according to claim 1 , wherein the zoom lens is satisfied and at least one surface of the second lens disposed in the first lens group has an aspherical shape.
(10) −0.5 <f _w / f ₂
However,
f ₂ : Focal length of the second lens from the magnification side in the first lens group The second lens group, a positive lens in order from the magnifying side, a negative lens of a convex meniscus shape on the magnification side, a positive lens, a negative lens, is composed of five positive lenses, lens group constituting the second lens group The following conditional expression (11) is satisfied with respect to the shape on the magnification side of the lens arranged on the most magnification side, and the dispersion characteristics of the glass material used for each of the five lenses constituting the second lens group are as follows. The conditional expression (12) is satisfied, and the following conditional expression (13) is satisfied with respect to a dispersion characteristic of a glass material disposed on the most reduction side of the second lens group . Zoom lens .
(11) 0.2 <f _w / r _{II 1} <1.0
_{(12) 25 <(V 6} + V 8 + V 10) / 3- (V 7 + V 9) / 2
(13) 69 <V ₁₀
However,
r _{II 1} : radius of curvature V ₆ of the magnifying side surface of the lens arranged closest to the magnifying side of the second lens group V ₆ : Abbe number V _{7 of the} positive lens laid out closest to the magnifying side of the second lens group In the second lens group, the Abbe number V _{8 of} the second lens arranged from the magnifying side is V ₈ : The Abbe number V _{9 of the} positive lens arranged from the magnifying side in the second lens group is V ₉ : From the magnifying side in the second lens group Abbe number V _{10 of the} negative lens arranged in the fourth lens: Abbe number of the positive lens arranged closest to the reduction side in the second lens group At least one surface of the lens arranged on the most magnifying side of the second lens group has an aspherical shape, and the following conditional expression (14) regarding the power of the lens arranged on the fourth lens from the magnifying side of the second lens group 5. The zoom according to claim 4 , wherein the following conditional expression (15) is satisfied with respect to a shape of a reduction side surface of a lens arranged closest to the reduction side of the second lens group. Lens .
_{(14) -0.9 <f w /} f 9 <-0.7
(15) −0.6 <f _w / r _{II 10} <−0.1
However,
f ₉ : Focal length r _{II 10 of the} lens arranged on the fourth lens from the magnification side of the second lens group ₁₀ : Radius of curvature of the reduction side surface of the lens arranged closest to the reduction surface of the second lens group Projector apparatus, characterized in that is equipped with a zoom lens that will be described in at least one of one of claims 1 to 5.