JP6123624B2 - Image display device - Google Patents

Description

The present invention relates to an image display device.
The image display device can be suitably implemented as a projector device.

  In recent years, a front projection type projector device that projects an enlarged image on a screen in front of the device has been widely used for presentations in companies, education in schools, and home use.

  In recent years, a zoom lens for projection has been required to be “high magnification and wide angle”.

  As what meets such a request, those described in Patent Documents 1 and 2 are known.

  The projection zoom lens described in Patent Document 1 has a negative, negative, positive, negative, and positive five-lens group configuration, and aberrations at the time of zooming are sufficiently suppressed, but a half angle of view at the wide angle end: ωw is 30. Stays at °.

  The projection zoom lens described in Patent Document 2 has a negative, negative, positive, positive, and positive five lens group configuration and sufficiently suppresses aberration, but the half angle of view at the wide angle end: ωw is 20.8 °. Stay on.

In general, a “lens used for image projection” is different from a camera lens system in that “oblique light” is used as an imaging light beam.
In the case of a camera taking lens, the entire effective area of the lens can be used. On the other hand, in a lens used for image projection, a projected image is formed by oblique rays.
For this reason, in the lens used for image projection, the range that can be used as the image projection area is a part of the effective area of the lens.

  For this reason, in order to increase the area of the projection surface onto which the image is projected, it is necessary to widen the angle of the projection zoom lens.

  Further, recently, there is a strong demand to reduce the projection distance of the projector device and “place the projector device closer to the projection surface”.

  In order to realize a projection surface having a large area with such a close arrangement to the projection surface, further widening of the angle is desired for the projection zoom lens.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to realize a novel image display device having a large angle of view of a projected image.

The image display device of the present invention is a light source, an image display element that displays an image for projection, an illumination optical system that illuminates the image display element with light emitted from the light source, and is irradiated by the illumination optical system, A projection optical system that receives a projection light beam modulated by a projection image displayed on the image display element and projects a magnified image of the image on a projection surface, and is reduced as a projection optical system from the enlargement side. toward the side, a fifth lens group structure formed by arranging the first lens group to the fifth lens group, the first lens group has a negative refractive power, the second lens group, the negative refractive power The third lens group has a positive refractive power, and among the first to fifth lens groups, the fifth lens group has the smallest refractive power in absolute value, and telephoto from the wide-angle end. upon zooming to end, the first lens group is fixed, the fifth lens group expansion Go to the side, the spacing between the lens groups adjacent changes,
Half angle of view at wide-angle end: ωw, conditions:
(1) A projection zoom lens satisfying 34 degrees ≦ ωw <45 degrees is used.

According to the present invention, a novel image display device capable of displaying a projection image having a large angle of view can be realized.
In the following, “to” is a symbol that abbreviates “to”.

3 is a cross-sectional view illustrating a configuration of a projection zoom lens according to Embodiment 1. FIG. 3 is an aberration curve diagram of the projection zoom lens of Example 1. FIG. 6 is a cross-sectional view illustrating a configuration of a projection zoom lens according to Example 2. FIG. FIG. 6 is an aberration curve diagram of the projection zoom lens according to Example 2. 6 is a cross-sectional view illustrating a configuration of a projection zoom lens according to Example 3. FIG. 6 is an aberration curve diagram of the projection zoom lens of Example 3. FIG. 6 is a cross-sectional view illustrating a configuration of a projection zoom lens according to Example 4. FIG. 6 is an aberration curve diagram of the projection zoom lens of Example 4. FIG. 10 is a cross-sectional view illustrating a configuration of a projection zoom lens according to Example 5. FIG. FIG. 10 is an aberration curve diagram of the projection zoom lens according to Example 5. 10 is a cross-sectional view illustrating a configuration of a projection zoom lens according to Example 6. FIG. 10 is an aberration curve diagram of the projection zoom lens of Example 6. FIG. 10 is a cross-sectional view illustrating a configuration of a projection zoom lens according to Example 7. FIG. 10 is an aberration curve diagram of the projection zoom lens of Example 7. FIG. 10 is a cross-sectional view illustrating a configuration of a projection zoom lens according to Example 8. FIG. FIG. 10 is an aberration curve diagram of the projection zoom lens according to Example 8. 10 is a cross-sectional view illustrating a configuration of a projection zoom lens according to Example 9. FIG. 10 is an aberration curve diagram of the projection zoom lens of Example 9. FIG. 10 is a cross-sectional view illustrating a configuration of a projection zoom lens according to Example 10. FIG. FIG. 10 is an aberration curve diagram of the projection zoom lens according to Example 10; 14 is a cross-sectional view illustrating a configuration of a projection zoom lens according to Example 11. FIG. FIG. 14 is an aberration curve diagram of the projection zoom lens according to Example 11; 14 is a cross-sectional view illustrating a configuration of a projection zoom lens according to Example 12. FIG. FIG. 14 is an aberration curve diagram of the projection zoom lens according to Example 12; FIG. 14 is a cross-sectional view illustrating a configuration of a projection zoom lens according to Example 13; FIG. 20 is an aberration curve diagram of the projection zoom lens according to Example 13; FIG. 22 is a cross-sectional view illustrating a configuration of a projection zoom lens according to Example 14; FIG. 20 is an aberration curve diagram of the projection zoom lens according to Example 14; It is a schematic block diagram of the projector apparatus as an image display apparatus. It is sectional drawing which shows the structure of the zoom lens for a projection of a comparative example. It is an aberration curve figure of the zoom lens for projection of a comparative example. FIG. 2 is a chromatic aberration diagram of magnification of the projection zoom lens of Example 1; 6 is a chromatic aberration diagram of magnification of a projection zoom lens according to Example 2. FIG. FIG. 6 is a chromatic aberration diagram of magnification of the projection zoom lens of Example 3; FIG. 6 is a chromatic aberration diagram of magnification of the projection zoom lens of Example 4; FIG. 9 is a chromatic aberration diagram of a magnification of the projection zoom lens of Example 5. FIG. 10 is a chromatic aberration diagram of magnification of a projection zoom lens according to Example 6. FIG. 10 is a chromatic aberration diagram of a magnification of the projection zoom lens of Example 7. FIG. 12 is a chromatic aberration diagram of a magnification of a projection zoom lens according to Example 8. 10 is a chromatic aberration diagram of magnification of the projection zoom lens of Example 9. FIG. FIG. 10 is a chromatic aberration diagram of magnification of a projection zoom lens according to Example 10; FIG. 10 is a chromatic aberration diagram of magnification of a projection zoom lens according to Example 11; FIG. 22 is a chromatic aberration diagram of magnification of a projection zoom lens according to Example 12; FIG. 20 is a chromatic aberration diagram of magnification of a zoom lens for projection according to Example 13. FIG. 20 is a chromatic aberration diagram of magnification of a projection zoom lens according to Example 14;

  Hereinafter, embodiments for carrying out the invention will be described.

The zoom lens used in the image display device of the present invention is the “projection zoom lens” as described above.
As described above, in the “projection lens”, the imaging light beam is “oblique light beam”.

  The projection zoom lens used as the projection optical system in the image display apparatus of the present invention also uses “oblique light beam” as the projection light beam for forming the projected image.

  1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, and 27, the zoom lens for projection is implemented. 14 examples are shown.

The zoom lenses according to these embodiments correspond to specific examples 1 to 14 described later in this order.
In each of the above figures, the left side of the figure is the “enlargement side” and the right side is the “reduction side”. In order to avoid complications, the symbols are shared in these drawings.
In each of the drawings, reference numeral G1 indicates a first lens group, reference numeral G2 indicates a second lens group, reference numeral G3 indicates a third lens group, reference numeral G4 indicates a fourth lens group, and reference numeral G5 indicates a fifth lens group.

  That is, the projection zoom lens shown in each of the above embodiments has a five-lens group configuration in which the first to fifth lens groups G1 to G5 are arranged from the enlargement side toward the reduction side.

  An “aperture stop” is disposed below the third lens group G3.

  Further, in each of the above drawings, the symbol CG indicates “a cover glass of an image display element (light valve)”.

  For each lens, in the i-th lens group Gi (i = 1 to 5), the j-th lens counted from the magnification side is denoted by reference symbol Lij.

  In these embodiments and examples, “DMD as a micromirror device” is assumed as the light valve, but of course, the light valve is not limited to this.

  In the above figures, the upper diagram shows “lens group arrangement at the wide angle end (indicated as wide angle)”, and the lower diagram shows “lens group arrangement at the telephoto end (indicated as telephoto)”.

  Also, the arrows drawn between the upper and lower figures in these figures indicate the transition of the second lens group G2 to the fifth lens group G5 during zooming from the wide-angle end to the telephoto end. Indicates direction.

In the projection zoom lens according to the embodiment shown in each of the drawings, both the first lens group G1 and the second lens group G2 have a negative refractive power, and the third lens group has a positive refractive power.
That is, in the first to fifth lens groups, the refractive power distribution of the first lens group G1 to the third lens group G3 is “negative / negative / positive”.

The refractive power of the fourth lens group G4 and the fifth lens group G5 can be positive for the fourth lens group and “positive or negative” for the fifth lens group.
The refractive power of the fourth lens group G4 and the fifth lens group G5 can also be negative for the fourth lens group and “positive or negative” for the fifth lens group.
That is, combinations of refractive powers of the fourth and fifth lens groups G4 and G5 can be combinations of “positive / negative”, “positive / positive”, “negative / negative”, and “negative / positive”.
In general, it is known that the chromatic aberration of magnification can be effectively reduced by applying a symmetric configuration of a lens in a “positive-negative-negative-positive” configuration that is a Gaussian type of a single focus lens.
However, the symmetry configuration in the zoom lens is not known.
In the present invention, by changing the first lens group as a fixed group (focus group) during zooming and moving the fifth lens group from the second lens group, fluctuations in various aberrations during zooming can be suppressed small.
In addition, the configuration of the second lens group to the fifth lens group is changed to “negative / positive / positive / negative” having a symmetrical configuration with the third lens group and the fourth lens group as a boundary, so that even during zooming, In addition, the lateral chromatic aberration and distortion can be controlled to be small.
Examples 1, 2, 3, 4, 5, 8, 9, 10, 11, and 14, which will be described later, have “negative / positive / positive / negative” configurations in which the second to fifth lens groups are symmetrical. It is.
With respect to the chromatic aberration of magnification for these examples, as shown in FIGS. 32, 33, 34, 35, 36, 39, 40, 41, 42, and 45, high-level chromatic aberration correction can be performed.
In addition, even if the second lens unit to the fifth lens unit are set to “negative / positive / negative / negative”, if the first lens unit is included, the symmetrical “negative / negative / positive” centering on the third lens unit is included. It becomes a “negative / negative” configuration, and it becomes possible to control the lateral chromatic aberration and distortion aberration to be small.
The twelfth embodiment has a “negative / negative / positive / negative / negative” configuration in which the first to fifth lens groups are symmetrical.
As shown in FIG. 43, the chromatic aberration diagram of the twelfth embodiment can highly correct lateral chromatic aberration.
Further, even in the configurations of “negative / positive / positive / positive” and “negative / positive / negative / positive” in which the second lens unit to the fifth lens unit have no symmetry, the positive lens unit on the most reduction side (the fifth lens unit) By making the power (= 1 / focal length) of the lens group the smallest among all the lens groups, it becomes possible to correct lateral chromatic aberration correction equivalent to that of a symmetrical lens configuration. In this regard, Example 6 and Example 7 have a “negative / positive / positive / positive” configuration, and FIGS. 49 and 50 show lateral chromatic aberration diagrams of Examples 5 and 6, respectively.
In addition, FIG. 56 shows a chromatic aberration diagram of magnification in Example 13 in which the second lens unit to the fifth lens unit are “negative / positive / negative / positive”.
The chromatic aberration of magnification is almost the same as that of the symmetrical configuration, and the chromatic aberration of magnification can be reduced by making the fifth lens group the weakest power.
In addition, when the moving group at the time of zooming is “negative / positive / positive / negative” or “negative / positive / positive / positive”, the lens configuration of the moving group is the most enlarged side of the moving group. The 2 lens group is composed of 4 lenses of “Positive / Negative / Positive / Negative”, and the 5th lens group on the most reducing side of the moving group is composed of 4 lenses of “Negative / Positive / Negative / Positive”. Thus, the chromatic aberration of magnification can be further reduced by adopting a “symmetrical” lens configuration in the second lens group and the fifth lens group.

Condition (1) defines the range of the half angle of view at the wide angle end.
That is, the half angle of view at the wide angle end of the projection zoom lens according to the present invention is not less than 34 degrees and less than 45 degrees, and the zoom lens has a very wide angle of view.

  In order to satisfy these conditions, the negative lens group leading type is preferable, and the negative lens group is advanced by setting the refractive power distribution of the first lens group G1 to the third lens group G3 to “negative / negative / positive”. ing.

  By setting the negative lens group in advance, the principal ray height can be further reduced, and the effective lens diameter can be reduced. Therefore, a wide-angle projection zoom lens can be realized in a compact manner.

  In addition, the “light beam jump angle” from the second lens group to the first lens group during image projection can be kept small.

  At the time of image projection, a projection light beam (light beam by oblique rays) from the light valve side is guided from the fifth lens group side to the first lens group side.

  At this time, since both the first lens group G1 and the second lens group G2 are negative, the divergence angle of the light beam from the third lens group can be easily expanded by the second and first lens groups.

  Therefore, as described above, the jump angle of the light beam transferred from the second lens group to the first lens group can be kept small, and the divergence angle of the radiated light beam from the first lens group can be increased reasonably.

  In addition, there is an effect of suppressing performance deterioration due to the eccentricity of the lens at the time of manufacture.

  At the time of zooming from the wide angle end to the telephoto end, the fifth lens group G5 moves to the enlargement side.

  By moving the fifth lens to the enlargement side, it is possible to reduce the “aberration fluctuation accompanying zooming”, and in particular, it is possible to reduce the fluctuation amount of the field curvature.

  In addition, it is possible to correct axial chromatic aberration.

  The projection zoom lens used in the image display apparatus according to the present invention can realize further better performance by satisfying one or more of the following conditions (2) and (3) in addition to the above-described configuration.

(2) | F4 | <| F5 |
(3) 0.9 <F4-5w / F4-5t <1.1.

  The meanings of the parameter symbols in the conditions (2) and (3) are as follows.

  “F4” is the focal length of the fourth lens group, and “F5” is the focal length of the fifth lens group.

  “F4-5w” is the combined focal length of the fourth lens group and the fifth lens group at the wide-angle end, and “F4-5t” is the combined focal length of the fourth lens group and the fifth lens group at the telephoto end.

  As described above, the combination of the refractive power of the fourth lens group and the refractive power of the fifth lens group can be “positive / negative, positive / positive, negative / negative, negative / positive”.

  Therefore, the combined focal lengths F4 and F5 may be “positive” or “negative”.

  Condition (2) defines the magnitude relationship between the absolute values of these combined focal lengths: F4 and F5.

  When the condition (2) is not satisfied, it is difficult to balance the power distribution of the entire projection zoom lens system, and various aberrations are likely to increase.

  By satisfying the condition (2), it is easy to balance the power distribution of the entire system, and it is easy to correct various aberrations.

The refractive power of the fifth lens group is the smallest in “absolute value ” among the first to fifth lens groups .
If the refractive power of the fifth lens group is larger than the refractive power of the other lens groups in absolute value, it becomes difficult to balance the power distribution of the entire system, which tends to increase various aberrations.

  If the upper limit of the condition (3) is exceeded, the “difference in the combined focal length of the fourth lens group and the fifth lens group” becomes large during zooming, and spherical aberration and axial chromatic aberration tend to become large during zooming.

  Also, astigmatism at the telephoto end tends to increase.

  When the lower limit of condition (3) is exceeded, coma at the telephoto end tends to increase.

By satisfying condition (3), it is possible to suppress an increase in astigmatism and coma at the telephoto end, and to effectively suppress variations in spherical aberration and axial chromatic aberration during zooming.
As described above, the refractive power of the fourth lens group can be “positive” or “negative”.
When the refractive power of the fourth lens group is “negative”, the following conditions in the range of the condition (1):
(1A) 43 degrees <ωw <45 degrees
It is better to satisfy the following conditions:
(2A) | F4 | <| F5 |
(3A) 0.9 <F4-5w / F4-5t <1.1
It is preferable to satisfy one or more of the following. These conditions (1A) to (3A) are within the ranges of the conditions (1) to (3).
The parameters of the conditions (2A) to (3A) are the same as the parameters of the above conditions (2) to (3).
In the configuration in which the fourth lens group has a “negative” refractive power, by satisfying the condition (1A), and further satisfying one or more of the conditions (2A) and (3A), the above-described condition (1 ) To (3) can function in the same manner.
When the refractive power of the fourth lens group is “positive”, the following conditions in the range of the condition (1):
(1B) 34 degrees ≦ ωw <45 degrees
It is better to satisfy the following conditions:
(2B) | F4 | <| F5 |
(3B) 0.9 <F4-5w / F4-5t <1.1
It is preferable to satisfy one or more of the following.
These conditions (1B) to (3B) are within the ranges of the conditions (1) to (3).
The parameters of the conditions (2B) to (3B) are the same as the parameters of the above conditions (2) to (3).
In the configuration in which the fourth lens group has a “positive” refractive power, by satisfying the condition (1B) and further satisfying one or more of the conditions (2B) and (3B), the above-described condition (1 ) To (3) can function in the same manner.

  At the time of zooming from the wide angle end to the telephoto end, it is preferable that the second lens group gently moves to the reduction side, and the third lens group and the fourth lens group individually move to the enlargement side.

  When zooming from the wide-angle end to the telephoto end, if the second lens group to the fourth lens group are moved as described above, it is possible to reduce the aberration fluctuation, particularly the coma aberration fluctuation quantity associated with the zooming. .

  In this case, if the first lens group G1 is fixed, the third, fourth, and fifth lens groups are displaced toward the enlargement side, and the second lens group is displaced toward the reduction side.

By making the displacement of the first lens group to the fifth lens group in this way, it is easy to suppress aberration fluctuations at the time of zooming, and it is possible to realize a compact and high-performance projection zoom lens.
Further, since the third lens unit to the fifth lens unit are displaced to the enlargement side at the time of zooming from the wide angle end to the telephoto end, a “long back focus” can be ensured even at the time of zooming.

  Therefore, it is easy to use a micromirror device such as DMD as a light valve of a projection zoom lens.

Before giving a specific example of a zoom lens, a mode of a projector apparatus will be briefly described with reference to FIG.
The projector device is an example of an image display device, and includes a light source, an image display element, an illumination optical system, and a projection optical system.
The “image display device” is a light valve and displays a projection image.
The “illumination optical system” illuminates the image display element with light emitted from a light source.
The “projection optical system” is irradiated with a projection light beam that is irradiated by the illumination optical system and modulated by the projection image displayed on the image display element, and projects an enlarged image of the image onto the projection surface.

  The projector apparatus 1 shown in FIG. 29 is an example in which a DMD that is a micromirror device is employed as the light valve 3.

  The projector device 1 includes an illumination system 2, a DMD 3 that is a light valve, and a projection zoom lens 4.

  As the projection zoom lens 4, one described in any one of claims 1 to 7, specifically, any one of Examples 1 to 14 is used.

  The “light of three colors RGB” is temporally separated from the illumination system 2 and irradiated to the DMD 3, and the tilt of the micromirror corresponding to each pixel is controlled at the timing when each color light is irradiated.

  In this way, the “image to be projected” is displayed on the DMD 3, and the light whose intensity is modulated by the image is enlarged by the projection zoom lens 4 and enlarged and projected on the screen 5.

The tilt angle of the micromirror is about ± 10 degrees, and the effective reflected light (effective light) and the invalid reflected light (ineffective light) are switched by switching the tilt angle.
When a micromirror device is used as a light valve, the projection zoom lens needs to capture the effective light satisfactorily and not capture invalid light as much as possible.

  In order to meet this need, the projection zoom lens is preferably arranged in the “normal direction of the image display surface on which micromirrors are arrayed”.

  In such an arrangement of the projection zoom lens, the light source of the illumination system needs to be installed adjacent to the projection zoom lens.

  Therefore, it is necessary to reduce the lens diameter on the light valve side of the projection zoom lens so that the reduction side portion of the projection zoom lens does not block the illumination light with respect to the image display surface.

  The illumination system 2 includes a light source 21, a condenser lens CL, an RGB color wheel CW, and a mirror M, and it is necessary to “ensure a certain amount of space” for arranging the light source 21.

For this reason, it is necessary to increase the incident angle of the illumination light incident on the DMD 3 from the illumination system 2 to some extent.
Due to the above-described relationship between the space between the projection zoom lens 4 and the illumination system 2, the back focus of the projection zoom lens 4 needs to be "secured to some extent".

  The condenser lens CL, the RGB color wheel CW and the mirror M constitute an “illumination optical system”.

In the following, 14 specific examples of the projection zoom lens according to the present invention will be described.
In the following, a lens group having a positive refractive power is referred to as a “positive group”, and a lens group having a negative refractive power is referred to as a “negative group”.

The meanings of symbols in each embodiment are as follows.
F: Focal length of the entire optical system
Fno: numerical aperture R: radius of curvature (“paraxial radius of curvature” for aspheric surfaces)
D: Surface spacing Nd: Refractive index Vd: Abbe number
BF: Back focus.

  The aspherical surface is represented by the following well-known expression.

^{X = (H 2 / R)} / [1+ {1-K (H / r) 2} 1/2]
+ C4 · H ⁴ + C6 · H ⁶ + C8 · H ⁸ + C10 · H ¹⁰ +.

  In this equation, X is “displacement in the direction of the optical axis at the position of the height H from the optical axis with respect to the surface vertex”, K is the “conical coefficient”, C4, C6, C8, C10. Aspheric coefficient.

"Example 1"
The projection zoom lens of Example 1 is shown in FIG.

  As shown in FIG. 1, the first lens group G1 includes lenses L11 to L13, and the second lens group G2 includes lenses L21 to L24.

  The third lens group G3 is composed of one lens L31, and the fourth lens group G4 is composed of two lenses L41 and L42.

  The fifth lens group G5 is composed of four lenses L51 to L54.

  As described above, a DMD is assumed as the light valve, and the DMD has a cover glass CG.

  During zooming from the wide-angle end to the telephoto end, the second lens group G2 moves to the reduction side, and the third lens group G3 to the fifth lens group G5 move to the enlargement side.

  The first lens group G1 is a negative group, and includes a negative meniscus lens L11 that is convex on the enlargement side, a negative lens L12 that has a concave surface on the enlargement side, and a negative meniscus lens L13 that is concave on the reduction side.

  The second lens group G2 is a negative group, and includes a biconvex lens L21, a biconcave lens L22, a positive meniscus lens L23 convex on the reduction side, and a negative meniscus lens L24 concave on the enlargement side.

  The positive meniscus lens L23 and the negative meniscus lens L24 are cemented.

The third lens group G3 is a positive group and includes a single biconvex lens L31.
The fourth lens group G4 is a positive group, and includes a positive meniscus lens L41 that is convex on the enlargement side, and a positive meniscus lens L42 that is convex on the enlargement side.

  The fifth lens group G5 is a negative group, and includes a negative meniscus lens L51 that is convex on the enlargement side, a biconvex lens L52, a negative meniscus lens L53 that is concave on the enlargement side, and a biconvex lens L54.

  The negative meniscus lens L51 and the biconvex lens L52 are cemented.

  In the description regarding Examples 1 to 14, the “biconvex lens” is a positive lens, and the “biconcave lens” is a negative lens.

  The focal length: F range, F number, half angle of view at the wide angle end: ωw of the entire system in Example 1 are as follows.

F = 13.0 to 19.6 mm, Fno = 2.55 to 3.34, ωw = 42.1 °
The data of Example 1 is shown in Table 1.

  In Table 1, the surface number is the number of the surface counted from the enlarged side, and includes the surface of the aperture stop (surface number: 20 in the table) and the surface of the cover glass CG (surface numbers: 28, 29 in the table). .

  “INF” in the table indicates that the radius of curvature is infinite. Furthermore, “*” indicates that the surface with this symbol is “aspherical surface”.

These matters are the same in each of the following embodiments.
In the first exemplary embodiment, the group configuration of the first lens unit G1 to the fifth lens unit G5 is “negative / negative / positive / positive / negative”.

"Aspherical data"
The aspherical data is shown in Table 2.

  In Table 1, S6, S13, S15, and S20 represent lens group intervals that change during zooming.

  Table 3 shows the distance between the lens groups when the projection distance is 1600 mm for the wide-angle end, the middle, and the telephoto end.

"Parameter values for each condition"
Table 4 shows parameter values of the conditions (1) to (3).

FIG. 2 shows aberration diagrams of Example 1.
The upper part of FIG. 2 shows the aberration at the “wide-angle end (displayed as wide angle)”, the middle part shows the aberration at “intermediate focal length (displayed as intermediate)”, and the lower part shows the aberration at the “telephoto end (displayed by telescope)”.

  In the aberration diagrams at each stage, the left diagram is “spherical aberration”, the middle diagram is “astigmatism”, and the right diagram is “distortion aberration”.

R, G, and B in the “spherical aberration” diagram represent wavelengths: R = 625 nm, G = 550 nm, and B = 460 nm, respectively.
In the “astigmatism” diagram, “T” indicates tangential and “S” indicates sagittal rays.

  Astigmatism and distortion are shown for a wavelength of 550 nm.

These indications in the aberration diagrams are the same in the aberration diagrams of Examples 2 to 14 below.
FIG. 32 shows a chromatic aberration diagram of magnification in Example 1.
The upper part of FIG. 32 shows the chromatic aberration of magnification at the “wide-angle end”, the middle part at “intermediate focal length (displayed as intermediate)”, and the lower part at the “telephoto end”.
In the figure, the alternate long and short dash line (BR) represents “blue lateral chromatic aberration when red is used as a base”, and the solid line (RG) represents “red lateral chromatic aberration when green is used as a base”.

"Example 2"
The projection zoom lens of Example 2 is shown in FIG.

As shown in FIG. 3, the first lens group G1 includes lenses L11 to L13, and the second lens group G2 includes lenses L21 to L24.
The third lens group G3 includes one lens L31, the fourth lens group G4 includes lenses L41 and L42, and the fifth lens group G5 includes lenses L51 to L54.

  During zooming from the wide-angle end to the telephoto end, the second lens group G2 moves to the reduction side, and the third lens group G3 to the fifth lens group G5 move to the enlargement side.

  The first lens group G1 is a negative group, and includes a negative meniscus lens L11 convex on the enlargement side, a negative negative lens L12 on the enlargement side, and a negative meniscus lens L13 concave on the reduction side.

  The second lens group G2 is a negative group, and includes a biconvex lens L21, a biconcave lens L22, a positive meniscus lens L23 convex on the reduction side, and a negative meniscus lens L24 concave on the enlargement side.

  The positive meniscus lens L32 and the negative meniscus lens L24 are cemented.

  The third lens group G3 is a positive group and includes a single biconvex lens L31.

  The fourth lens group G4 is a positive group, and includes a positive meniscus lens L41 that is convex on the enlargement side, and a biconvex lens L42 that has a large curvature on the convex surface on the enlargement side.

  The fifth lens group G5 is a negative group, and includes a biconcave lens L51, a biconvex lens L52, a negative meniscus lens L53 concave on the enlargement side, and a biconvex lens L54.

  The biconcave lens L51 and the biconvex lens L52 are cemented.

  In Example 2, the focal length of the entire system: F range, F number, and half angle of view at the wide-angle end: ωw are as follows.

F = 13.0 to 19.6 mm, Fno = 2.55 to 3.34, ωw = 42.1 °
The data of Example 2 is shown in Table 5.

In Example 2, the group configuration of the first lens group G1 to the fifth lens group G5 is “negative / negative / positive / positive / negative”.
"Aspherical data"
Table 6 shows the aspherical data.

  Table 7 shows lens group intervals: S6, S13, S15, and S20 when the projection distance is 1600 mm for the wide-angle end, the middle, and the telephoto end.

"Parameter values for each condition"
Table 8 shows parameter values of the conditions (1) to (3).

  FIG. 4 is an aberration diagram of Example 2 similar to FIG. FIG. 33 shows a chromatic aberration diagram of magnification in Example 2.

"Example 3"
The projection zoom lens of Example 3 is the one shown in FIG.

As shown in FIG. 5, the first lens group G1 is composed of lenses L11 to L13, and the second lens group G2 is composed of lenses L21 to L24.
The third lens group G3 includes a lens L31, the fourth lens group G4 includes lenses L41 and L42, and the fifth lens group G5 includes lenses L51 to L54.

  During zooming from the wide-angle end to the telephoto end, the second lens group G2 moves to the reduction side, and the third lens group G3 to the fifth lens group G5 move to the enlargement side.

  The first lens group G1 is a negative group, and includes a negative meniscus lens L11 convex on the enlargement side, a negative negative lens L12 on the enlargement side, and a negative negative meniscus lens L13 on the reduction side.

  The second lens group G2 is a negative group, and includes a biconvex lens L21, a biconcave lens L22, a positive meniscus lens L23 convex on the reduction side, and a negative meniscus lens L24 concave on the enlargement side.

  The positive meniscus lens L23 and the negative meniscus lens L24 are cemented.

  The third lens group G3 is a positive group and includes a single biconvex lens L31.

  The fourth lens group G4 is a positive group, and includes a positive meniscus lens L41 and a biconvex lens L42 that are convex on the enlargement side.

  The fifth lens group G5 is a negative group, and includes a negative meniscus lens L51 that is convex on the enlargement side, a biconvex lens L52, a negative meniscus lens L53 that is concave on the enlargement side, and a biconvex lens L54.

  The negative meniscus lens L51 and the biconvex lens L52 are cemented.

  In Example 3, the focal length of the entire system: the range of F, the F number, and the half field angle at the wide angle end: ωw are as follows.

F = 13.0 to 19.6 mm, Fno = 2.55 to 3.34, ωw = 42.1 °
The data of Example 3 is shown in Table 9.

In Example 3, the group configuration of the first lens group G1 to the fifth lens group G5 is “negative / negative / positive / positive / negative”.
"Aspherical data"
Table 10 shows the aspheric data.

  Table 11 shows the lens group intervals S6, S13, S15, and S20 when the projection distance is 1600 mm for the wide-angle end, the middle, and the telephoto end.

"Parameter values for each condition"
Table 12 shows parameter values of the conditions (1) to (3).

  FIG. 6 is an aberration diagram of Example 3 similar to FIG. FIG. 34 shows a chromatic aberration diagram of magnification in Example 3.

"Example 4"
The projection zoom lens of Example 4 is shown in FIG.

As shown in FIG. 7, the first lens group G1 includes lenses L11 to L13, and the second lens group G2 includes lenses L21 to L24.
The third lens group G3 includes lenses L31 and L32, the fourth lens group G4 includes lens L41, and the fifth lens group G5 includes lenses L51 to L54.

  During zooming from the wide-angle end to the telephoto end, the second lens group G2 moves to the reduction side, and the third lens group G3 to the fifth lens group G5 move to the enlargement side.

  The first lens group G1 is a negative group, and includes a negative meniscus lens L11 that is convex on the enlargement side, a negative meniscus lens L12 that is concave on the enlargement side, and a negative meniscus lens L13 that is concave on the reduction side.

The second lens group G2 is a negative group, and includes a biconvex lens L21, a biconcave lens L22, a positive meniscus lens L23 convex on the reduction side, and a negative meniscus lens L24 concave on the enlargement side.
The positive meniscus lens L23 and the negative meniscus lens L24 are cemented.

  The third lens group G3 is a positive group, and includes a biconvex lens L31 and a positive meniscus lens L32 convex on the enlargement side.

  The fourth lens group G4 is a positive group and includes a biconvex lens L41.

  The fifth lens group G5 is a negative group, and includes a negative meniscus lens L51 that is concave on the reduction side, a biconvex lens L52, a negative meniscus lens L53 that is concave on the enlargement side, and a biconvex lens L54.

  The negative meniscus lens L51 and the biconvex lens L52 are cemented.

  In Example 4, the focal length of the entire system: F range, F number, and half angle of view at the wide angle end: ωw are as follows.

F = 13.0 to 19.6 mm, Fno = 2.55 to 3.34, ωw = 42.1 °
The data of Example 4 is shown in Table 13.

In Example 4, the group configuration of the first lens group G1 to the fifth lens group G5 is “negative / negative / positive / positive / negative”.
"Aspherical data"
Table 14 shows the aspheric data.

  Table 15 shows lens group intervals S6, S13, S17, and S20 when the projection distance is 1600 mm for the wide-angle end, the middle, and the telephoto end.

"Parameter values for each condition"
Table 16 shows parameter values of the conditions (1) to (3).

  FIG. 8 shows aberration diagrams of Example 4 according to FIG. FIG. 35 shows a chromatic aberration diagram of magnification in Example 4.

"Example 5"
The projection zoom lens of Example 5 is shown in FIG.

  As shown in FIG. 9, the first lens group G1 is composed of lenses L11 to L13, and the second lens group G2 is composed of lenses L21 to L24.

  The third lens group G3 is composed of one lens L31, the fourth lens group G4 is composed of one lens L41, and the fifth lens group G5 is composed of lenses L51 to L54.

  During zooming from the wide-angle end to the telephoto end, the second lens group G2 moves to the reduction side, and the third lens group G3 to the fifth lens group G5 move to the enlargement side.

  The first lens group G1 is a negative group, and includes a negative meniscus lens L11 convex on the enlargement side, a negative negative lens L12 on the enlargement side, and a negative meniscus lens L13 concave on the reduction side.

The second lens group G2 is a negative group, and includes a biconvex lens L21, a biconcave lens L22, a positive meniscus lens L23 convex on the reduction side, and a negative meniscus lens L24 concave on the enlargement side.
The positive meniscus lens L23 and the negative meniscus lens L24 are cemented.

  The third lens group G3 is a positive group and includes a single biconvex lens L31.

  The fourth lens group G4 is a positive group and includes a single biconvex lens L41.

  The fifth lens group G5 is a negative group, and includes a biconcave lens L51, a biconvex lens L52, a negative meniscus lens L53 concave on the enlargement side, and a biconvex lens L54.

  The biconvex lens L51 and the biconcave lens L52 are cemented.

  In Example 4, the focal length of the entire system: F range, F number, and half angle of view at the wide angle end: ωw are as follows.

F = 13.0 to 19.6 mm, Fno = 2.55 to 3.35, ωw = 42.1 °
The data of Example 5 is shown in Table 17.

In Example 5, the group configuration of the first lens group G1 to the fifth lens group G5 is “negative / negative / positive / positive / negative”.
"Aspherical data"
Table 18 shows the aspheric data.

  Table 19 shows lens group intervals S6, S13, S15, and S18 when the projection distance is 1600 mm for the wide-angle end, the middle, and the telephoto end.

"Parameter values for each condition"
Table 20 shows parameter values of the conditions (1) to (3).

  FIG. 10 is an aberration diagram of Example 5 similar to FIG. FIG. 36 shows a chromatic aberration diagram of magnification in Example 5.

"Example 6"
The projection zoom lens of Example 6 is the one shown in FIG.

  As shown in FIG. 11, the first lens group G1 includes lenses L11 to L13, and the second lens group G2 includes lenses L21 to L24.

  The third lens group G3 includes one lens L31, the fourth lens group G4 includes L41 and L42, and the fifth lens group G5 includes lenses L51 to L54.

  During zooming from the wide-angle end to the telephoto end, the second lens group G2 moves to the reduction side, and the third lens group G3 to the fifth lens group G5 move to the enlargement side.

  The first lens group G1 is a negative group, and includes a negative meniscus lens L11 convex on the enlargement side, a negative negative lens L12 on the enlargement side, and a negative meniscus lens L13 concave on the reduction side.

  The second lens group G2 is a negative group, and includes a biconvex lens L21, a negative meniscus lens L22 concave on the reduction side, a positive meniscus lens L23, and a negative meniscus lens L24.

  The positive meniscus lens L23 is “convex on the reduction side” and the negative meniscus lens L24 is “concave on the enlargement side”. These positive and negative meniscus lenses L23 and L24 are cemented.

  The third lens group G3 is a positive group and includes a single biconvex lens L31.

  The fourth lens group G4 is a positive group, and includes a positive meniscus lens L41 and a biconvex lens L42 that are convex on the enlargement side.

  The fifth lens group G5 is a positive group, and includes a biconcave lens L51, a biconvex lens L52, a negative meniscus lens L53 concave on the enlargement side, and a biconvex lens L54.

  The biconcave lens L51 and the biconvex lens L52 are cemented.

  In Example 6, the focal length of the entire system: the range of F, the F number, and the half angle of view at the wide-angle end: ωw are as follows.

F = 13.0 to 19.6 mm, Fno = 2.58 to 3.24, ωw = 42.1 °
The data of Example 6 is shown in Table 21.

In Example 6, the group configuration of the first lens group G1 to the fifth lens group G5 is “negative / negative / positive / positive / positive”.
The focal lengths (mm) of the first lens group G1 to the fifth lens group G5 are sequentially
-23.2, -58.4, 62.9, 26.3, 406.3
The power (1 / focal length) of the fifth lens group G5 is the smallest.
"Aspherical data"
Table 22 shows the aspherical data.

  Table 23 shows lens group intervals S6, S13, S15, and S20 when the projection distance is 1600 mm for the wide-angle end, the middle, and the telephoto end.

"Parameter values for each condition"
Table 24 shows parameter values of the conditions (1) to (3).

  FIG. 12 is an aberration diagram of Example 6 similar to FIG. FIG. 37 shows a chromatic aberration diagram of magnification in Example 6.

"Example 7"
The projection zoom lens of Example 7 is shown in FIG.

  As shown in FIG. 13, the first lens group G1 includes lenses L11 to L13, and the second lens group G2 includes lenses L21 to L24.

  The third lens group G3 includes one lens L31, the fourth lens group G4 includes lenses L41 and L42, and the fifth lens group G5 includes lenses L51 to L54.

  During zooming from the wide-angle end to the telephoto end, the second lens group G2 moves to the reduction side, and the third lens group G3 to the fifth lens group G5 move to the enlargement side.

  The first lens group G1 is a negative group, and includes a negative meniscus lens L11 convex on the enlargement side, a negative negative lens L12 on the enlargement side, and a negative negative meniscus lens L13 on the reduction side.

  The second lens group G2 is a negative group, and includes a biconvex lens L21, a negative meniscus lens L22 concave on the reduction side, a positive meniscus lens L23, and a negative meniscus lens L24.

  The positive meniscus lens L23 is “convex on the reduction side”, the negative meniscus lens L24 is concave on the enlargement side, and these positive and negative meniscus lenses L23 and L24 are cemented.

  The third lens group G3 is a positive group and includes a single biconvex lens L31.

  The fourth lens group G4 is a positive group, and includes a positive meniscus lens L41 and a biconvex lens L42 that are convex on the enlargement side.

  The fifth lens group G5 is a positive group, and includes a biconcave lens L51, a biconvex lens L52, a negative meniscus lens L53 concave on the enlargement side, and a biconvex lens L54.

  The biconcave lens L51 and the biconvex lens L52 are cemented.

  In Example 7, the focal length of the entire system: the range of F, the F number, and the half angle of view at the wide angle end: ωw are as follows.

F = 13.0 to 19.6 mm, Fno = 2.58 to 3.24, ωw = 42.1 °
The data of Example 7 is shown in Table 25.

In Example 7, the group configuration of the first lens group G1 to the fifth lens group G5 is “negative / negative / positive / positive / positive”.
The focal lengths (mm) of the first lens group G1 to the fifth lens group G5 are sequentially
-24.0, -55.9, 47.0, 30.2, 2433.5
The power (1 / focal length) of the fifth lens group G5 is the smallest.
"Aspherical data"
Table 26 shows the aspherical data.

  Table 27 shows the lens group spacings S6, S13, S15, and S20 when the projection distance is 1600 mm for the wide-angle end, the middle, and the telephoto end.

"Parameter values for each condition"
Table 28 shows parameter values of the conditions (1) to (3).

  FIG. 14 is an aberration diagram of Example 7 similar to FIG. FIG. 38 shows a chromatic aberration diagram of magnification in Example 7.

"Example 8"
The projection zoom lens of Example 8 is shown in FIG.

As shown in FIG. 15, the first lens group G1 is composed of lenses L11 to L13, and the second lens group G2 is composed of lenses L21 to L24.
The third lens group G3 includes one lens L31, the fourth lens group G4 includes lenses L41 and L42, and the fifth lens group G5 includes lenses L51 to L54.

  During zooming from the wide-angle end to the telephoto end, the second lens group G2 moves to the reduction side, and the third lens group G3 to the fifth lens group G5 move to the enlargement side.

  The first lens group G1 is a negative group, and includes a negative meniscus lens L11 convex on the enlargement side, a negative negative lens L12 on the enlargement side, and a negative meniscus lens L13 concave on the reduction side.

  The second lens group G2 is a negative group, and includes a biconvex lens L21, a biconcave lens L22, a positive meniscus lens L23 having a convex surface on the reduction side, and a negative meniscus lens L24 having a concave surface on the enlargement side.

  The positive meniscus lens L23 and the negative meniscus lens L24 are cemented.

  The third lens group G3 is a positive group and includes a single biconvex lens L31.

  The fourth lens group G4 is a positive group, and includes a positive meniscus lens L41 and a biconvex lens L42 that are convex on the enlargement side.

  The fifth lens group G5 is a negative group, and includes a negative meniscus lens L51 that is convex on the enlargement side, a biconvex lens L52, a negative meniscus lens L53 that is concave on the enlargement side, and a biconvex lens L54.

The negative meniscus lens L51 and the biconvex lens L52 are cemented.
Although the refractive power of the fifth lens group G5 is negative, this negative refractive power is weak.

  In Example 8, the focal length of the entire system: the range of F, the F number, and the half angle of view at the wide angle end: ωw are as follows.

F = 14.2 to 21.1 mm, Fno = 2.55 to 3.34, ωw = 39.6 °
The data of Example 8 is shown in Table 29.

In Example 8, the group configuration of the first lens group G1 to the fifth lens group G5 is “negative / negative / positive / positive / negative”.
"Aspherical data"
Table 30 shows the aspherical data.

  Table 31 shows lens group intervals S6, S13, S15, and S20 when the projection distance is 1600 mm for the wide-angle end, the middle, and the telephoto end.

"Parameter values for each condition"
Table 32 shows parameter values of the conditions (1) to (11).

  FIG. 16 is an aberration diagram of Example 8 similar to FIG. FIG. 39 shows a chromatic aberration diagram of Example 8 in magnification.

"Example 9"
The projection zoom lens of Example 9 is shown in FIG.

  As shown in FIG. 1, the first lens group G1 includes lenses L11 to L13, and the second lens group G2 includes lenses L21 to L24.

  The third lens group G3 includes one lens L31, the fourth lens group G4 includes lenses L41 and L42, and the fifth lens group G5 includes lenses L51 to L54.

  During zooming from the wide-angle end to the telephoto end, the second lens group G2 moves to the reduction side, and the third lens group G3 to the fifth lens group G5 move to the enlargement side.

  The first lens group G1 is a negative group, and includes a negative meniscus lens L11 convex on the enlargement side, a negative negative lens L12 on the enlargement side, and a negative meniscus lens L13 concave on the reduction side.

  The second lens group G2 is a negative group, and includes a biconvex lens L21, a biconcave lens L22, a positive meniscus lens L23 convex on the reduction side, and a negative meniscus lens L24 concave on the enlargement side.

  The positive meniscus lens L23 and the negative meniscus lens L24 are cemented.

  The third lens group G3 is a positive group and includes a single biconvex lens L31.

  The fourth lens group G4 is a positive group, and includes a positive meniscus lens L41 and a biconvex lens L42 that are convex on the enlargement side.

  The fifth lens group G5 is a negative group having a weak refractive power, and includes a negative meniscus lens L51 convex to the enlargement side, a biconvex lens L52, a negative meniscus lens L53, and a biconvex lens L54.

  The negative meniscus lens L53 is “concave on the enlargement side”. The negative meniscus lens L51 and the biconvex lens L52 are cemented.

  The focal length of the entire system in Example 9: F range, F number, and half angle of view at the wide angle end: ωw are as follows.

F = 13.8 to 20.5 mm, Fno = 2.55 to 3.34, ωw = 40.4 °
The data of Example 9 is shown in Table 33.

In Example 9, the group configuration of the first lens group G1 to the fifth lens group G5 is “negative / negative / positive / positive / negative”.
"Aspherical data"
Table 34 shows the aspherical data.

  Table 35 shows lens group intervals S6, S13, S15, and S20 when the projection distance is 1600 mm for the wide-angle end, the middle, and the telephoto end.

"Parameter values for each condition"
Table 36 shows parameter values of the conditions (1) to (3).

  FIG. 18 is an aberration diagram of Example 9 similar to FIG. FIG. 40 shows a chromatic aberration diagram of magnification in Example 9.

"Example 10"
The projection zoom lens of Example 10 is shown in FIG.

  As shown in FIG. 19, the first lens group G1 is composed of lenses L11 to L13, and the second lens group G2 is composed of lenses L21 to L24.

  The third lens group G3 is composed of a single lens L31, the fourth lens group G4 is composed of lenses L41 and L42, and the fifth lens group G5 is composed of lenses L51 to L54.

  During zooming from the wide-angle end to the telephoto end, the second lens group G2 moves to the reduction side, and the third lens group G3 to the fifth lens group G5 move to the enlargement side.

  The first lens group G1 is a negative group, and includes a negative meniscus lens L11 convex on the enlargement side, a negative negative lens L12 on the enlargement side, and a negative meniscus lens L13 concave on the reduction side.

  The second lens group G2 is a negative group, and includes a biconvex lens L21, a biconcave lens L22, a positive meniscus lens L23 convex on the reduction side, and a negative meniscus lens L24 concave on the enlargement side.

  The positive meniscus lens L23 and the negative meniscus lens L24 are cemented.

  The third lens group G3 is a positive group and includes a single biconvex lens L31.

  The fourth lens group G4 is a positive group, and includes a positive meniscus lens L41 and a biconvex lens L42 that are convex on the enlargement side.

  The fifth lens group G5 is a negative group having a weak refractive power, and includes a negative meniscus lens L51 having a convex surface on the enlargement side, a biconvex lens L52, a negative meniscus lens L53, and a biconvex lens L54.

  The negative meniscus lens L53 is “concave on the enlargement side”, and the negative meniscus lens L51 and the biconvex lens L52 are cemented.

  In Example 10, the focal length of the entire system: the range of F, the F number, and the half angle of view at the wide angle end: ωw are as follows.

F = 12.4 to 18.5 mm, Fno = 2.56 to 3.34, ωw = 43.3 °
The data of Example 10 is shown in Table 37.

In Example 10, the group configuration of the first lens group G1 to the fifth lens group G5 is “negative / negative / positive / positive / negative”.
"Aspherical data"
Table 38 shows the aspherical data.

  Table 39 shows lens group intervals S6, S13, S15, and S20 when the projection distance is 1600 mm for the wide-angle end, the middle, and the telephoto end.

"Parameter values for each condition"
Table 40 shows parameter values of the conditions (1) to (3).

  FIG. 20 is an aberration diagram of Example 10 similar to FIG. FIG. 41 shows a chromatic aberration diagram of magnification in Example 10.

"Example 11"
The projection zoom lens of Example 11 is the one shown in FIG.

  As shown in FIG. 21, the first lens group G1 includes lenses L11 to L13, and the second lens group G2 includes lenses L21 to L24.

  The third lens group G3 includes one lens L31, the fourth lens group G4 includes lenses L41 and L42, and the fifth lens group G5 includes lenses L51 to L54.

  During zooming from the wide-angle end to the telephoto end, the second lens group G2 moves to the reduction side, and the third lens group G3 to the fifth lens group G5 move to the enlargement side.

  The first lens group G1 is a negative group, and includes a negative meniscus lens L11 convex on the enlargement side, a negative negative lens L12 on the enlargement side, and a negative meniscus lens L13 concave on the reduction side.

  The second lens group G2 is a negative group, and includes a biconvex lens L21, a biconcave lens L22, a positive meniscus lens L23 convex on the reduction side, and a negative meniscus lens L24 concave on the enlargement side.

  The positive meniscus lens L23 and the negative meniscus lens L24 are cemented.

  The third lens group G3 is a positive group and includes a single biconvex lens L31.

  The fourth lens group G4 is a positive group, and includes a positive meniscus lens L41 and a biconvex lens L42 that are convex on the enlargement side.

  The fifth lens group G5 is a negative group having a weak refractive power, and includes a negative meniscus lens L51 that is convex on the enlargement side, a biconvex lens L52, a negative meniscus lens L53, and a biconvex lens L54.

  The negative meniscus lens L53 is “concave on the enlargement side”, and the negative meniscus lens L51 and the biconvex lens L52 are cemented.

  In Example 11, the focal length of the entire system: F range, F number, and half angle of view at the wide angle end: ωw are as follows.

F = 11.8 to 17.6 mm, Fno = 2.56 to 3.34, ωw = 44.8 °
The data of Example 11 are shown in Table 41.

In Example 11, the group configuration of the first lens group G1 to the fifth lens group G5 is “negative / negative / positive / positive / negative”.
"Aspherical data"
Table 42 shows aspherical data.

  Table 43 shows lens group intervals S6, S13, S15, and S20 when the projection distance is 1600 mm for the wide-angle end, the middle, and the telephoto end.

"Parameter values for each condition"
Table 44 shows parameter values of the conditions (1) to (3).

  FIG. 22 shows aberration diagrams of Example 11 following FIG. FIG. 42 shows a chromatic aberration diagram of magnification in Example 11.

"Example 12"
The projection zoom lens of Example 12 is shown in FIG.

  As shown in FIG. 23, the first lens group G1 includes lenses L11 and L12, and the second lens group G2 includes lenses L21 to L24.

  The third lens group G3 is composed of lenses L31 and L32, the fourth lens group G4 is composed of lenses L41 to L44, and the fifth lens group G5 is composed of a single lens L51.

  During zooming from the wide-angle end to the telephoto end, the second lens group G2 moves to the reduction side, and the third lens group G3 to the fifth lens group G5 move to the enlargement side.

  The first lens group G1 is a negative group, and includes a negative meniscus lens L11 that is convex on the enlargement side, and a negative lens L12 that is concave on the reduction side.

  The second lens group G2 is a negative group, and includes a negative meniscus lens L21 convex on the enlargement side, a positive meniscus lens L22 convex on the enlargement side, a biconcave lens L23, and a biconvex lens L24.

  The negative meniscus lens L21 and the positive meniscus lens L22 are cemented.

  The third lens group G3 is a positive group, and includes a positive meniscus lens L31 and a biconvex lens L32 that are convex on the enlargement side.

  The fourth lens group G4 is a negative group, and includes a biconcave lens L41, a biconvex lens L42, a negative meniscus lens L43 concave on the enlargement side, and a biconvex lens L44.

  The biconcave lens L41 and the biconvex lens L42 are cemented.

  The fifth lens group G5 is a negative group, and includes a single negative meniscus lens L51 that is concave on the enlargement side.

  In Example 12, the focal length of the entire system: the range of F, the F number, and the half field angle at the wide angle end: ωw are as follows.

F = 12.3 to 17.9 mm, Fno = 2.56 to 3.34, ωw = 43.6 °
The data of Example 12 is shown in Table 45.

In Example 12, the group configuration of the first lens unit G1 to the fifth lens unit G5 is “negative / negative / positive / negative / negative”.
"Aspherical data"
Table 46 shows aspherical data.

  Table 47 shows lens group intervals S4, S11, S16, and S23 when the projection distance is 1600 mm, at the wide-angle end, the middle, and the telephoto end.

"Parameter values for each condition"
Table 48 shows parameter values of the conditions (1) to (3).

  FIG. 24 shows aberration diagrams of Example 12 according to FIG. FIG. 43 shows a chromatic aberration diagram of magnification in Example 12.

"Example 13"
The projection zoom lens of Example 13 is shown in FIG.

  As shown in FIG. 25, the first lens group G1 includes lenses L11 and L12, and the second lens group G2 includes lenses L21 to L24.

  The third lens group G3 is composed of lenses L31 and L32, the fourth lens group G4 is composed of lenses L41 and L42, and the fifth lens group G5 is composed of a single lens L51.

  During zooming from the wide-angle end to the telephoto end, the second lens group G2 moves to the reduction side, and the third lens group G3 to the fifth lens group G5 move to the enlargement side.

  The first lens group G1 is a negative group, and includes a negative meniscus lens L11 that is convex on the enlargement side, and a negative lens L12 that is concave on the reduction side.

  The second lens group G2 is a negative group, and includes a negative meniscus lens L21 convex on the enlargement side, a positive meniscus lens L22 convex on the enlargement side, a biconcave lens L23, and a biconvex lens L24.

  The negative meniscus lens L21 and the positive meniscus lens L22 are cemented.

  The third lens group G3 is a positive group, and includes a positive meniscus lens L31 and a biconvex lens L32 that are convex on the enlargement side.

  The fourth lens group G4 is a negative group, and includes a biconcave lens L41, a biconvex lens L42, a negative meniscus lens L43 concave on the enlargement side, and a biconvex lens L44.

  The biconcave lens L41 and the biconvex lens L42 are cemented.

  The fifth lens group G5 is a positive group and includes a single biconvex lens L51.

  In Example 13, the focal length of the entire system: the range of F, the F number, and the half angle of view at the wide angle end: ωw are as follows.

F = 12.3 to 17.9 mm, Fno = 2.56 to 3.34, ωw = 43.6 °
The data of Example 13 are shown in Table 49.

In Example 13, the group configuration of the first lens group G1 to the fifth lens group G5 is “negative / negative / positive / negative / positive”.
The focal lengths (mm) of the first lens group G1 to the fifth lens group G5 are sequentially
-42.1, -43.4, 22.0, -63.3, 168.4
The power (1 / focal length) of the fifth lens group G5 is the smallest.
"Aspherical data"
Table 50 shows aspherical data.

  Table 51 shows lens group intervals S4, S11, S16, and S23 when the projection distance is 1600 mm, at the wide-angle end, the middle, and the telephoto end.

"Parameter values for each condition"
Table 52 shows parameter values of the conditions (1) to (3).

  FIG. 26 shows aberration diagrams of Example 13 following FIG. FIG. 44 shows a chromatic aberration diagram of Example 13 for magnification.

"Example 14"
The projection zoom lens of Example 14 is shown in FIG.

  As shown in FIG. 27, the first lens group G1 includes lenses L11 to L13, and the second lens group G2 includes lenses L21 to L24.

  The third lens group G3 includes one lens L31, the fourth lens group G4 includes lenses L41 and L42, and the fifth lens group G5 includes lenses L51 to L54.

  During zooming from the wide-angle end to the telephoto end, the second lens group G2 moves to the reduction side, and the third lens group G3 to the fifth lens group G5 move to the enlargement side.

  The first lens group G1 is a negative group, and includes a negative meniscus lens L11 convex on the enlargement side, a negative negative lens L12 on the enlargement side, and a negative meniscus lens L13 concave on the reduction side.

  The second lens group G2 is a negative group, and includes a biconvex lens L21, a biconcave lens L22, a positive meniscus lens L23 convex on the reduction side, and a negative meniscus lens L24 concave on the enlargement side.

  The positive meniscus lens L23 and the negative meniscus lens L24 are cemented.

  The third lens group G3 is a positive group and includes a single biconvex lens L31.

  The fourth lens group G4 is a positive group, and includes a positive meniscus lens L41 and a planoconvex positive lens L42 that are convex on the enlargement side.

  The fifth lens group G5 is a negative group, and includes a planoconcave negative lens L51, a biconvex lens L52, a negative meniscus lens L53 concave on the enlargement side, and a biconvex lens L54.

  The plano-concave negative lens L51 and the biconvex lens L52 are cemented.

  In Example 14, the focal length of the entire system: the range of F, the F number, and the half field angle at the wide angle end: ωw are as follows.

F = 17.4 to 26 mm, Fno = 2.55 to 3.33, ωw = 34.0 °
The data for Example 14 are shown in Table 53.

In Example 14, the group configuration of the first lens group G1 to the fifth lens group G5 is “negative / negative / positive / positive / negative”.
"Aspherical data"
Table 54 shows the aspherical data.

  Table 55 shows lens group intervals S6, S13, S15, and S20 when the projection distance is 1600 mm for the wide-angle end, the middle, and the telephoto end.

"Parameter values for each condition"
Table 56 shows parameter values of the conditions (1) to (3).

  FIG. 28 shows aberration diagrams of Example 14 according to FIG. FIG. 45 is a chromatic aberration diagram of magnification in Example 14.

As shown in the aberration diagrams, in the projection zoom lenses according to the respective embodiments, various aberrations are corrected at a high level, and spherical aberration, astigmatism, curvature of field, lateral chromatic aberration, and distortion are sufficiently corrected.
Further, as shown in the chromatic aberration diagram of magnification, the chromatic aberration of magnification is corrected at a high level even during zooming in each of the projection zoom lenses of the respective examples.
In addition, each of the projection zoom lenses according to Examples 1 to 14 satisfies the conditions (1) to (3).
In Example 12 and Example 13, the fourth lens group is a “negative group” and has negative refractive power, and the parameters of the conditions (1) to (3) are the conditions (1A) to (3A) described above. ) Is satisfied.
In Examples other than Examples 12 and 13, the fourth lens group is a “positive group” and has a positive refractive power, and each parameter of the conditions (1) to (3) is the same as the above-described condition (1B ) To (3B) are satisfied.

  As shown in Examples 1 to 14, the first lens group G1 is composed of two or three lenses.

  A lens having a large lens diameter is used as the first lens group, but the first lens group can be reduced in weight by using two or three first lens groups as in the embodiment.

This weight reduction can suppress the eccentricity of the lens due to its own weight.
In Examples 1 to 14, the first lens group G1 has a “correction effect for astigmatism and distortion”.

  In Examples 1 to 14, the first lens group G1 has “the most enlargement surface is convex on the enlargement side and the most reduction surface is concave”.

  By doing so, an effect of “reducing fluctuations in field curvature and distortion” at the time of zooming can be obtained.

  In any of the projection zoom lenses of Examples 1 to 14, the first lens group G1 is fixed and the fifth lens group G5 moves to the enlargement side during zooming from the wide-angle end to the telephoto end.

  Then, the second lens group gently moves to the reduction side, and the third lens group and the fourth lens group individually move to the enlargement side.

  The projection zoom lens according to the present invention has a “wide angle of view” in which the half angle of view at the wide angle end is larger than 34 degrees, and the second lens group G2 is gently moved to the reduction side when zooming to the telephoto end. I am letting.

  By doing so, fluctuations in various aberrations during zooming can be reduced.

  In each of the projection zoom lenses of Examples 1 to 14, the first lens group G1 is fixed when the zoom is changed from the wide angle end to the telephoto end with a "wide angle of view" in which the half angle of view at the wide angle end is 34 degrees or more. It is.

  The second lens group G2 moves to the reduction side, and the third lens group G3 to the fifth lens group G5 move to the enlargement side.

  By doing so, fluctuations in various aberrations during zooming can be reduced.

  As shown in Examples 1 to 14, the first lens group G1 is composed of two or three lenses.

  A lens having a large lens diameter is used as the first lens group. However, the first lens group can be reduced in weight by using two or three lenses.

This weight reduction can suppress the eccentricity of the lens due to its own weight.
The focal length of the first lens group: F1 and the focal length of the second lens group: F2 are regulated by the condition (5), but the ratio of F1, F2: F1 / F2 has the following range (a) preferable.

(A) 0.1 <F1 / F2 <1.0
The range (a) is effective for correcting astigmatism and field curvature.

  Further, it is preferable that the composite focal length f1_3w of the first lens group to the third lens group is in the following range (b).

(B) 0 <1 / | f1_3w | <0.14
The ratio of the combined focal length: f1_3w to the focal length: fw of the entire system at the wide angle end is preferably in the following range (c).

(C) 0.5 <| f1_3w / fw | <8.0
If 1 / | f1 — 3w | is in the range of (b), aberration correction by the second lens group G2 at the time of zooming is suitable, and it is effective for avoiding remaining aberrations such as coma.

  Setting | f1 — 3w / fw | within the range of (c) is effective in suppressing coma and lateral chromatic aberration.

  In the projection zoom lenses of Examples 1 to 14, the first lens group G1 is given “an effect of correcting astigmatism and distortion”.

  The first lens group G1 is “a lens surface closest to the enlargement is convex on the enlargement side, and a lens surface closest to the reduction is concave on the reduction side”.

  “The radius of curvature of the most magnified lens surface: R1f and the radius of curvature of the most demagnified lens surface: R1r” of the first lens group are preferably in the range of (A).

(A) 1.3 <R1f / R1r <2.1
Within the range of (A), the amount of refraction of the two surfaces can be well balanced, which is effective for “suppression of occurrence of color difference in coma”.

  Further, the ratio (fw / F1) between the focal length of the entire system at the wide-angle end: fw and the focal length of the first lens unit: F1: fw / F1 is preferably in the following range (B).

(B) 0.2 <| fw / F1 | <0.8
When fw / F1 is set within the range of (B), the negative power of the first lens group can easily balance the power distribution of the entire projection zoom lens well, and the balance of various aberrations can be made good.

  Further, the value “DISw” of the optical distortion in the effective image circle at the wide angle end at the projection distance: 1600 mm is preferably in the following range (C).

(C) -1.35% <DISw <0.0%
In this range of optical distortion, “TV distortion” is good.

  In this case, if an “aspheric lens” is arranged in the first lens group and its focal length: fsph is in the following range (D), it is easy to satisfy (C).

(D) 1.0 × 10 ⁻³ <1 / | fsph | <2.0 × 10 ⁻²
The “projection distance” refers to the distance between the projection surface and the most magnified lens surface of the projection zoom lens.

  In the projection zoom lens according to each embodiment, the first lens group G1 is a focus group, the second lens group G2 is a compensator (aberration correction group), and the third lens group is a zooming group.

  The material of the lens constituting the second lens group preferably satisfies one or more of the following (d) to (i).

(D) Nd2p · νd2p <Nd2n · νd2n
(E) 1.70 <Nd2p <2.10
(F) 18.0 <νd2p <30.0
(G) 1.45 <Nd2n <1.75
(H) 48.0 <νd2n <90.0
(I) 1.0 <| f2p / f2n | <2.0
In these conditions (d) to (i), the symbols of the parameters are as follows.

  “Nd2p” is the refractive index of the d-line of the “positive lens with the lowest d-line Abbe number” among the positive lenses arranged in the second lens group, and “νd2p” is the Abbe number of the d-line of the positive lens. Represents.

  “Nd2n” is the refractive index of the d-line of the “negative lens with the highest d-line Abbe number” among the negative lenses arranged in the second lens group, and “νd2n” is the d-line Abbe number of the negative lens. Represents.

  “F2p” represents the focal length of the “positive lens having the lowest Abbe number of d-line” among the positive lenses arranged in the second lens group.

  “F2n” represents the focal length of the “negative lens having the highest Abbe number of d-line” among the negative lenses arranged in the second lens group.

  “F2p2n” represents the combined focal length of “a positive lens with the lowest d-line Abbe number” and “a negative lens with the highest d-line Abbe number” among the lenses arranged in the second lens group.

  Each of the ranges (d) to (h) is effective for suppressing lateral chromatic aberration. In the range (d), the coma and astigmatism are well balanced.

  The range (i) is effective for suppressing the field curvature fluctuation at the time of zooming.

  In order to increase the projection magnification, it is effective to satisfy the following condition (j).

(J) 0.3 <D3 / F3 or D4 / F4 <0.6
“F3” is the focal length of the third lens group, and “F4” is the focal length of the fourth lens group.

  “D3” is the amount of movement of the third lens group that moves during zooming from the wide-angle side to the telephoto side.

  “D4” is the amount of movement of the fourth lens group that moves during zooming from the wide-angle side to the telephoto side.

  When the upper limit of the condition (j) is exceeded, the astigmatic difference on the telephoto side tends to increase, and when the lower limit is exceeded, it becomes difficult to achieve a zoom ratio of 1.5 times.

  By satisfying the condition (j), an optimum solution for astigmatism correction can be obtained even when the zoom ratio is 1.5 times or more, and an increase in field curvature can be effectively suppressed.

  Among Examples 1 to 14, Examples 1 to 11 and 14 have the fourth lens group having a positive refractive power, and in Examples 12 and 13, the fourth lens group has a negative refractive power. ing.

  The first lens group G1 is composed of three lenses in Examples 1 to 11 and 14, and is composed of two lenses in Examples 12 and 13.

  In any of Examples 1 to 14, the “second lens from the magnification side” in the first lens group is an aspherical lens, and both surfaces are aspherical.

  As described above, the projection zoom lens according to the present invention is characterized in that “the fifth lens unit moves to the enlargement side” upon zooming from the wide-angle end to the telephoto end.

  Here, for comparison, a projection zoom lens that “fixes the fifth lens group upon zooming from the wide-angle end to the telephoto end” is given as a comparative example.

  FIG. 30 is a cross-sectional view of the configuration of the comparative example of the projection zoom lens, following FIG.

"Comparative example"
In the comparative example, the focal length of the entire system: F range, F number, and half angle of view at the wide angle end: ωw are as follows.

F = 13.0 to 19.6 mm, Fno = 2.55 to 3.34, ωw = 42.1 °
The data of the comparative example is shown in Table 57 following Table 1.

  In Table 57, “spherical” and “aspherical surface” indicate that the lens surface is “spherical surface” and “aspherical surface”.

  “Aspherical data” is shown in Table 58.

  Table 59 shows lens group intervals S6, S13, S15, and S20 when the projection distance is 1600 mm for the wide-angle end, the middle, and the telephoto end.

  FIG. 31 is an aberration diagram of the comparative example, following FIG.

  As is apparent from comparison between the aberration diagrams of the respective examples and the aberration diagrams of the comparative example, it can be seen that the aberration is significantly deteriorated as compared with the example in which the fifth lens unit moves to the enlargement side at the time of zooming.

  From this, the technical significance of “moving the fifth lens unit to the enlargement side at the time of zooming” is clear.

G1 first lens group
G2 second lens group
G3 Third lens group
G4 4th lens group
G5 5th lens group

JP 2011-69959 A Japanese Patent No. 4972763

Claims (4)

A light source;
An image display element for displaying an image for projection;
An illumination optical system that illuminates the image display element with light emitted from the light source;
A projection optical system that is irradiated with the illumination optical system and receives a projection light beam modulated by a projection image displayed on the image display element, and projects an enlarged image of the image on a projection surface; and
As a projection optical system,
A five-lens group configuration in which the first to fifth lens groups are arranged from the magnification side to the reduction side,
The first lens group has negative refractive power,
The second lens group has negative refractive power,
The third lens group has a positive refractive power,
Among the first lens group to the fifth lens group, the refractive power of the fifth lens group is the smallest in absolute value,
During zooming from the wide-angle end to the telephoto end, the first lens group is fixed, the fifth lens group moves to the enlargement side, and the spacing between adjacent lens groups changes,
Half angle of view at wide-angle end: ωw, conditions:
(1) An image display apparatus using a projection zoom lens satisfying 34 degrees ≦ ωw <45 degrees. The image display device according to claim 1,
A projection zoom lens used as a projection optical system
During zooming from the wide-angle end to the telephoto end, the second lens group moves to the reduction side, the third lens group moves to the enlargement side, and the fourth lens group moves to the enlargement side. An image display device. The image display device according to claim 1 or 2,
A projection zoom lens used as a projection optical system
The combined focal length of the fourth lens group and the fifth lens group at the wide angle end : F4-5w, and the combined focal length of the fourth lens group and the fifth lens group at the telephoto end: F4-5t are:
(3) 0.9 <F4-5w / F4-5t <1.1
An image display device characterized by satisfying the above . A light source;
An image display element for displaying an image for projection;
An illumination optical system that illuminates the image display element with light emitted from the light source;
A projection optical system that is irradiated with the illumination optical system and receives a projection light beam modulated by a projection image displayed on the image display element, and projects an enlarged image of the image on a projection surface; and
As a projection optical system,
A five-lens group configuration in which the first to fifth lens groups are arranged from the enlargement side toward the reduction side;
The first lens group has negative refractive power,
The second lens group has negative refractive power,
The third lens group has a positive refractive power,
Among the first lens group to the fifth lens group, the refractive power of the fifth lens group is the smallest in absolute value,
At the time of zooming, the first lens group is fixed, and the second lens group, the third lens group, the fourth lens group, and the fifth lens group move to the reduction side or the enlargement side, respectively, and adjacent lenses An image display device using a projection zoom lens in which a distance between groups changes .

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