JP2014174340A - Zoom projection optical system and image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a zoom projection optical system capable of effectively reducing variation associated with zooming operation of light volume used for projecting an expanded image.SOLUTION: A zoom projection optical system expands and projects an image being displayed on a light valve 1 onto a screen S with variable magnification, and includes a dioptric system 3 having two or more lens groups and an aperture stop ST. The dioptric system 3 has a zoom capability and, when zooming, a lens group located on the most light valve 1 side in the dioptric system and the aperture stop interlockingly move, changing the distance therebetween.

Description

  The present invention relates to a zoom projection optical system and an image display device.

  The image display device can be implemented as a projector device.

  A projector device is widely known as an image display device that enlarges and projects an image displayed on a light valve onto a screen surface by a projection optical system.

  The projection optical system of the projector device preferably has a “zoom function” that can change the size of a projected image (referred to as an image projected on a screen) at the same projection distance.

  As zoom projection optical systems having a zoom function, those disclosed in Patent Documents 1 to 3 are conventionally known.

  The zoom projection optical systems disclosed in Patent Documents 1 to 3 do not leave room for improvement in terms of reducing the change accompanying “magnification” of “the amount of light applied to the projection of the enlarged image”.

  It is an object of the present invention to realize a zoom projection optical system that can effectively reduce the change accompanying the magnification change in the amount of light applied to the projection of an enlarged image.

  The zoom projection optical system according to the present invention has a refractive optical system having two or more lens groups and an aperture stop in a zoom projection optical system for enlarging and projecting an image displayed on a light valve on a screen with variable magnification. The refractive optical system has a zoom function, and when zooming, the lens group closest to the light valve of the refractive optical system and the aperture stop move in conjunction with each other while changing the distance between them. Features.

  According to the present invention, it is possible to effectively reduce a change in the amount of light applied to the projection of the enlarged image due to the magnification change.

It is a figure for demonstrating the mode of image formation of a zoom projection optical system. It is a figure which expands and shows the part of the refractive optical system 2 and the mirror 4 of FIG. 1 is a diagram illustrating a configuration of Example 1. FIG. It is a figure which shows the data of Example 1. FIG. FIG. 6 is a diagram illustrating lens intervals regarding the zoom function and the focus function according to the first exemplary embodiment. It is a figure which shows the aspherical surface data of Example 1. It is a figure for demonstrating a light valve. FIG. 6 is a diagram illustrating a specific example of an image on an enlargement-side screen during short distance projection of the zoom projection optical system according to the first embodiment. FIG. 6 is a diagram illustrating a specific example of an image on a reduction-side screen during short distance projection of the zoom projection optical system according to the first embodiment. FIG. 6 is a diagram illustrating a specific example of an image on an enlargement-side screen during reference projection of the zoom projection optical system of Example 1. FIG. 5 is a diagram illustrating a specific example of an image on a reduction-side screen during reference projection of the zoom projection optical system according to the first embodiment. FIG. 6 is a diagram illustrating a specific example of an image on a screen on an enlargement side during long distance projection of the zoom projection optical system according to the first embodiment. FIG. 6 is a diagram illustrating a specific example of an image on a reduction-side screen during long distance projection of the zoom projection optical system according to the first exemplary embodiment. 6 is a diagram illustrating a configuration of Example 2. FIG. It is a figure which shows the data of Example 2. FIG. FIG. 6 is a diagram illustrating lens intervals related to a zoom function and a focus function in Example 2. It is a figure which shows the aspherical surface data of Example 2. It is a figure for demonstrating a light valve. FIG. 10 is a diagram illustrating a specific example of an image on a screen on an enlargement side when a short-distance projection is performed by the zoom projection optical system according to the second embodiment. FIG. 10 is a diagram illustrating a specific example of an image on a reduction-side screen during short-distance projection of the zoom projection optical system according to the second embodiment. FIG. 10 is a diagram illustrating a specific example of an image on an enlargement-side screen during reference projection of the zoom projection optical system according to the second embodiment. FIG. 10 is a diagram illustrating a specific example of an image on a reduction-side screen during reference projection of the zoom projection optical system according to the second embodiment. FIG. 12 is a diagram illustrating a specific example of an image on a screen on an enlargement side during long-distance projection of the zoom projection optical system of Example 2. FIG. 10 is a diagram illustrating a specific example of an image on a reduction-side screen during long-distance projection of the zoom projection optical system according to the second embodiment. 6 is a diagram illustrating a configuration of Example 3. FIG. It is a figure which shows the data of Example 3. FIG. 10 is a diagram illustrating lens intervals regarding the zoom function and the focus function according to the third exemplary embodiment. It is a figure which shows the aspherical surface data of Example 3. It is a figure for demonstrating a light valve. FIG. 10 is a diagram illustrating a specific example of an image on a screen on the enlargement side during short-distance projection of the zoom projection optical system of Example 3. FIG. 10 is a diagram illustrating a specific example of an image on a reduction-side screen during short-distance projection of the zoom projection optical system of Example 3. FIG. 10 is a diagram illustrating a specific example of an image on an enlargement-side screen during reference projection of the zoom projection optical system of Example 3. FIG. 10 is a diagram illustrating a specific example of an image on a reduction-side screen during reference projection of the zoom projection optical system of Example 3. FIG. 12 is a diagram illustrating a specific example of an image on a screen on an enlargement side during long-distance projection of the zoom projection optical system of Example 3. FIG. 10 is a diagram illustrating a specific example of an image on a reduction-side screen during long-distance projection of the zoom projection optical system of Example 3. It is a figure which shows the data of the focal distance of Examples 1-3. It is a figure for demonstrating one Embodiment of an image display apparatus.

Hereinafter, embodiments will be described.
FIG. 1 is a diagram for explaining a state of image formation of the zoom projection optical system.
In FIG. 1, a zoom projection optical system 100 enlarges and projects an image displayed on a light valve 1 on a screen 2 with a variable enlargement magnification.

The zoom projection optical system 100 includes a refractive optical system 3, and an aperture stop ST is disposed in the refractive optical system 3.
A zoom projection optical system 100 shown in FIG. 1 has a mirror 4 that reflects the light beam from the refractive optical system 3 to the screen 2 side. The mirror 4 is a concave mirror and has a positive refractive power.

  As described above, the zoom reflecting optical system of the present invention can have a mirror having refractive power in addition to the refractive optical system, but the mirror is not an essential component of the zoom reflecting optical system.

  FIG. 2 shows an enlarged view of the refractive optical system 2 and the mirror 4 shown in FIG.

The light valve 1 has a surface on which an image is displayed (hereinafter also referred to as “image display surface”), but a known appropriate light valve 1 can be used as the light valve 1.
That is, various types of transmissive and reflective liquid crystal panels, digital mirror devices (hereinafter referred to as “DMD”), and the like can be used.

  The refractive optical system 3 has two or more lens groups and an aperture stop ST.

  In the example shown in FIG. 2, during zooming, the “first lens group” closest to the light valve 1 and the “second lens group” on the enlargement side (right side in the figure) are displaced to perform zooming.

  In this example, the aperture stop ST is formed on the “lens surface closest to the light valve 1” of the second lens group. Of course, the aperture stop can be configured independently of the lens.

  In the example of FIG. 2, the aperture stop ST is integral with the second lens group, and zooming (also referred to as “zooming”) is performed when the first and second lens groups are displaced together.

  Accordingly, the first lens group closest to the light valve 1 and the aperture stop ST are displaced.

  This displacement is performed so that the distance between the first lens group and the aperture stop ST changes.

  At this time, by adjusting the displacement of the first lens group and the displacement of the aperture stop ST, the change in the numerical aperture (hereinafter also referred to as “NA”) on the light valve side of the refractive optical system can be adjusted.

  In other words, the change in the numerical aperture accompanying the zooming can be reduced, and in particular, the numerical aperture can be substantially unchanged.

  When zooming is performed so that the numerical aperture on the light valve side does not substantially change, the amount of light applied to the image formation is constant even if the magnification of the projected image projected on the screen changes.

  Therefore, even if the size of the projected image changes, the “change in brightness of the projected image” can be reduced.

  Further, when zooming is performed by moving the first lens group closest to the light valve, the degree of freedom in designing the zoom projection optical system becomes larger than in the case where this is used as a fixed group.

  Supplementally, the aperture stop can be provided independently of the lens constituting the refractive optical system and can be displaced independently of the lens group during zooming.

  However, as in the above example, it can be provided in the second lens group and displaced together with the second lens group.

  Furthermore, when the aperture stop is provided in the lens group, the lens group provided with the aperture stop can be provided not only in the second lens group from the light valve side but also in the third and subsequent lens groups.

  That is, the aperture stop can be provided in the second and subsequent lens groups from the light valve side.

  As described above, the zoom projection optical system of the present invention can be constituted only by a refractive optical system having an aperture stop. However, a mirror having refractive power may be disposed between the refractive optical system and the screen.

  When a mirror having refractive power is used, a zoom projection optical system including the function of the mirror can be designed, the degree of freedom in designing the zoom projection optical system is increased, and good performance can be easily realized.

  Further, the refracting power of the mirror can be utilized for the magnification, and the magnification can be further increased as compared with the case of only the refractive optical system, and a “shorter projection distance” is possible.

  “Projection distance” is a “distance on the optical axis” between the screen vertex and the surface vertex on the most enlarged side on the optical axis of the optical element (lens, mirror) constituting the zoom projection optical system.

  Therefore, the shorter the “projection distance” is, the closer the zoom projection optical system is to the screen.

  It is preferable that the lens group closest to the light valve 1 (the first lens group in the above description) is moved toward the light valve when zooming from the high magnification side to the low magnification side.

  In addition, two or more lens groups that do not move during zooming can be provided among a plurality of lens groups constituting the refractive optical system, and two or more of these can be used as “focus groups”.

  The “focus group” is a lens group that performs a focus function, that is, a function of focusing a projected image on a screen at different projection distances.

  Thus, by separating the lens group that moves at the time of zooming and the “lens group that moves at the time of focusing”, it becomes easy to focus the projected image with high accuracy.

  It is preferable that “focal length with respect to e line: f1” and “combined focal length with respect to e line of refractive optical system: f” of the lens group closest to the light valve satisfy the following condition (1).

(1) 2.4 <f1 / f <6.2
Condition (1) regulates the refractive power of the lens group closest to the light valve.

  When the upper limit of the condition (1) is exceeded, the refractive power of the lens group closest to the light valve becomes relatively weak with respect to the refractive power of the entire refractive optical system.

  For this reason, the spherical aberration in the entire zoom projection optical system tends to be insufficiently corrected.

  When the lower limit of the condition (1) is exceeded, the refractive power of the lens group closest to the light valve becomes relatively stronger than the refractive power of the entire refractive optical system.

  For this reason, the spherical aberration in the entire zoom projection optical system tends to be overcorrected.

  Therefore, outside the range of the condition (1), it is difficult to properly correct spherical aberration, and the image quality of the projected image is likely to be deteriorated due to deterioration of coma aberration.

  By satisfying the condition (1), it is easy to realize a high-quality projection image.

  The lens group constituting the refractive optical system requires a lens group used as a focus group in addition to the “lens group closest to the light valve” that moves during zooming.

  When the aperture stop moves independently of the other lens groups during zooming, the number of lens groups constituting the refractive optical system is at least two.

  In view of the performance of the zoom projection optical system, ease of zooming, compactness, etc., the lens group constituting the refractive optical system preferably has about five groups.

  Thus, when the refractive optical system is constituted by five lens groups, it is preferable that four of the lens groups have “positive refractive power”.

  The image display device of the present invention can be realized by using a DMD or various liquid crystal panels as light valves and using the zoom projection optical system of the present invention.

  Three specific examples of the zoom projection optical system will be described below.

  In the following examples, the unit of the quantity having the dimension of length is “mm” unless otherwise specified.

"Example 1"
The block diagram of Example 1 is shown in FIG.

  As shown in FIG. 3, the refractive optical system 3 includes five lens groups and an aperture stop ST from the light valve 1 side on the reduction side to the enlargement side.

  The five lens groups are a first lens group 3A, a second lens group 3B, a third lens group 3C, a fourth lens group 3D, and a fifth lens group 3E, arranged in the above order from the reduction side to the enlargement side. Yes.

  The first lens group 3A is composed of first to third lenses, and the second lens group 3B is composed of fourth to seventh lenses.

  The third lens group 3C is composed of an eighth lens to a tenth lens, and the fourth lens group 3D is composed of an eleventh lens and a twelfth lens.

  The fifth lens group 3E includes one thirteenth lens.

  These first to fifth lens groups 3A to 3E all have “positive refractive power”.

  The aperture stop ST is provided in the second lens group 3B. More specifically, it is formed on the reduction side surface of the fourth lens of the second lens group 3B.

  The first lens group 3A and the second lens group 3B constitute a “zoom group” that moves and changes magnification during zooming.

The third lens group 3C and the fourth lens group 3D constitute a focus group, and the fifth lens group 3E is a fixed group.
That is, the fifth lens group 3E does not move during zooming or focusing.

  The first lens group 3A moves away from the light valve 1 when zooming to the high magnification side, and moves closer to the light valve 1 when zooming to the low magnification side.

  In FIG. 4, “reduced” means “low magnification side”, and “expanded” means “high magnification side”. The same applies to the following.

  The second lens group 3B moves closer to the light valve 1 when zooming to the high magnification side, and moves away from the light valve 1 when zooming to the low magnification side.

  Accordingly, the aperture stop ST provided in the second lens group 3B moves in the opposite direction to the first lens group 3A in conjunction with the first lens group 3A during zooming.

  When focusing from the short distance side to the long distance side, the third lens group 3C and the fourth lens group 3D are moved away from the light valve 1 as shown in the figure.

  The zoom projection optical system of Embodiment 1 has a concave mirror 4 having refractive power on the image side of the refractive optical system 3.

The mirror 4 is a “rotationally symmetric aspherical surface”, and its rotational symmetry axis coincides with the optical axis of the refractive optical system 3, and the position of (Y = 0, Z = 278.16) in the “YZ plane” of FIG. The vertex of the face is matched.

  The origin (Y = 0, Z = 0) of the YZ coordinates is the intersection of the optical axis of the refractive optical system 3 and the “image display surface” of the light valve 1.

  The data of the zoom projection optical system of Example 1 is shown in FIG.

  The left column of FIG. 4 represents “surface number”, “r” is the radius of curvature of the surface, “d” is the wavefront spacing, “nd” is the refractive index of the lens material, and “νd” is the Abbe number. “D-line reference”.

  FIG. 5 shows lens interval data regarding the zoom function and the focus function of the zoom projection optical system according to the first embodiment.

  The aspherical surface is represented by the well-known lower formula by the height from the optical axis: Y and the distance from the tangential plane at the aspherical vertex of the aspherical surface at the height Y from the optical axis: Z.

Z = (1 / R) Y ² / [1-√ {1- (1 + K) (Y / R) ² }]
+ A4 ・ Y ⁴ + A6 ・ Y ⁶ + A8 ・ Y ⁸ + A10 ・ Y ¹⁰ + A12 ・ Y ¹² + A14 ・ Y ¹⁴
In the right side of the above formula, “R” is the paraxial radius of curvature of the surface, “K” is the conic constant, and A4, A6, etc. are “high-order aspherical coefficients”.

  Aspherical data are shown in FIG. 6 together with surface numbers “K, A4 to A14”.

In the notation shown in FIG. 6, for example, “9.62896E-11” means “9.62896 × 10 ⁻¹¹ ”. The same applies to the following.

  In the first embodiment, the numerical aperture on the object side is kept constant at 0.195 on both the enlargement side and the reduction side. That is, the numerical aperture is practically constant during zooming.

  FIG. 7 is a specific example of a light valve. In this specific example, a digital micromirror device (DMD) having a diagonal length of 0.65 inches is assumed as the light valve.

  Of course, the light valve is not limited to this example. For example, the size of the light valve may be set to a diagonal length of 0.55 inch.

  Of course, a transmissive or reflective liquid crystal panel can be used as a light valve.

  In the first embodiment, the distance between the optical axis of the refractive optical system and the “lower side in FIG. 3” of the image display surface of the light valve is shifted by 1.2 mm, but this distance can also be arbitrarily changed.

FIG. 8 is a specific example of a projection image with the maximum magnification on the screen during short-distance projection of the zoom projection optical system of the first embodiment.
This projection image is obtained by displaying the projection image on the screen at the maximum magnification by the zoom projection optical system of Example 1 using the light valve whose data is shown in FIG. 7 as the image display surface.

  The center diagram of FIG. 8 shows the arrangement of the imaging positions in the projection image of 25 pixels by causing “5 × 5 pixels” to emit light on the image display surface of the light valve.

  The upper diagram (upper side) and the lower diagram (lower side) in FIG. 8 show the imaging positions of 7 pixels at equal intervals on the uppermost side and the lowermost side in the center diagram of FIG.

  The left figure (left side) of FIG. 8 shows the imaging positions of five pixels on the left end side in the center figure of FIG. In each drawing of FIG. 8, the unit is “mm” for both the vertical and horizontal axes.

  9 and the subsequent drawings are the same as FIG.

  In FIG. 8, (enlarged side) means “maximum magnification”. The same applies to the following.

FIG. 9 is a specific example of a projected image with the minimum magnification on the screen during short-distance projection of the zoom projection optical system of the first embodiment.
This projection image is obtained by displaying the projection image on the screen at the minimum magnification by the zoom projection optical system of Example 1 using the light valve whose data is shown in FIG. 7 as the image display surface.

  In FIG. 9, (reduction side) means “minimum magnification”. The same applies to the following.

  FIG. 10 is a specific example of a projection image with the maximum magnification on the screen at the time of reference projection in the zoom projection optical system of the first embodiment.

  This projection image is obtained by displaying the projection image on the screen at the maximum magnification by the zoom projection optical system of Example 1 using the light valve whose data is shown in FIG. 7 as the image display surface.

  FIG. 11 is a specific example of a projection image of the minimum magnification on the screen at the time of standard projection of the zoom projection optical system of the first embodiment.

  This projection image is obtained by displaying the projection image on the screen at the minimum magnification by the zoom projection optical system of Example 1 using the light valve whose data is shown in FIG. 7 as the image display surface.

FIG. 12 is a specific example of a projection image with the maximum magnification on the screen during long distance projection of the zoom projection optical system of the first embodiment.
This projection image is obtained by displaying the projection image on the screen at the maximum magnification by the zoom projection optical system of Example 1 using the light valve whose data is shown in FIG. 7 as the image display surface.

FIG. 13 is a specific example of a projected image with the minimum magnification on the screen during long distance projection of the zoom projection optical system of the first embodiment.
This projection image is obtained by displaying the projection image on the screen at the minimum magnification by the zoom projection optical system of Example 1 using the light valve whose data is shown in FIG. 7 as the image display surface.

"Example 2"
FIG. 14 shows a configuration diagram of a specific example 2 of the zoom projection optical system.

  As shown in FIG. 14, the refractive optical system 3 includes five lens groups and an aperture stop ST from the light valve 1 side which is the reduction side to the enlargement side.

  The five lens groups are a first lens group 3F, a second lens group 3G, a third lens group 3H, a fourth lens group 3I, and a fifth lens group 3J, arranged in the above order from the reduction side to the enlargement side. Yes.

  The first lens group 3F is composed of first to third lenses, and the second lens group 3G is composed of fourth to seventh lenses.

  The third lens group 3H is composed of an eighth lens to a tenth lens, and the fourth lens group 3I is composed of an eleventh lens and a twelfth lens.

  The fifth lens group 3J includes one thirteenth lens.

  Among these five lens groups, the fourth lens group 3I has “negative refractive power”, and the other four lens groups 3F, 3G, 3H, and 3J all have “positive refractive power”.

  The aperture stop ST is provided in the second lens group 3G. More specifically, it is formed on the reduction side surface of the fourth lens of the second lens group 3G.

  The first lens group 3F and the second lens group 3G constitute a “zoom group” that moves during zooming and performs zooming.

The third lens group 3H and the fourth lens group 3I constitute a focus group, and the fifth lens group 3J is a fixed group.
That is, the fifth lens group 3J does not move during zooming or focusing.

  The first lens group 3F moves away from the light valve 1 when zooming to the high magnification side, and moves closer to the light valve 1 when zooming to the low magnification side.

  The second lens group 3G moves closer to the light valve 1 when zooming to the high magnification side, and moves away from the light valve 1 when zooming to the low magnification side.

  Therefore, the aperture stop ST provided in the second lens group 3G moves in the opposite direction to the first lens group 3F in conjunction with the first lens group 3F during zooming.

  When focusing from the short distance side to the long distance side, the third lens group 3H and the fourth lens group 3I move in a direction away from the light valve 1, as shown in the figure.

  The zoom projection optical system of Example 2 also has a concave mirror 4 having refractive power on the image side of the refractive optical system 3.

The mirror 4 is a “rotationally symmetric aspherical surface”, and its rotational symmetry axis is made coincident with the optical axis of the refractive optical system 3, and the position of (Y = 0, Z = 286.50) in the “YZ plane” of FIG. The vertex of the face is matched.

  The origin (Y = 0, Z = 0) of the YZ coordinates is the intersection of the optical axis of the refractive optical system 3 and the “image display surface” of the light valve 1.

  Data of the zoom projection optical system of Example 2 is shown in FIG. 15 following FIG.

  FIG. 16 is a diagram similar to FIG. 5 showing lens interval data regarding the zoom function and the focus function of the zoom projection optical system according to the second embodiment.

  Aspherical data is shown in FIG. 17 according to FIG.

  The numerical aperture on the object side is kept constant at 0.195 on both the enlargement side and the reduction side. That is, the numerical aperture is practically constant during zooming.

  A specific example of the light valve is shown in FIG.

  The light valve in FIG. 18 is the same as that shown in FIG. 7, but the distance between the optical axis of the refractive optical system and the “lower side in FIG. 14” of the image display surface of the light valve is shifted by 1.0 mm. ing.

  The light valve shown in FIG. 18 assumes a DMD having a diagonal length of 0.65 inches.

  The size and type of the light valve are not limited to this, and it may be a transmissive or reflective liquid crystal panel as in the case of the embodiment.

  Also, the shift amount between the optical axis and the lower side of the image display surface can be arbitrarily changed.

FIG. 19 shows a specific example of a projection image with the maximum magnification on the screen at the time of short distance projection in the zoom projection optical system of Example 2 according to FIG.
FIG. 20 shows a specific example of the projection image with the minimum magnification on the screen at the time of short-distance projection in the zoom projection optical system of Example 2 according to FIG.
FIG. 21 shows a specific example of the projection image with the maximum magnification on the screen at the time of the standard projection in the zoom projection optical system of Example 2 according to FIG.

  FIG. 22 shows a specific example of the projected image with the minimum magnification on the screen at the time of the standard projection in the zoom projection optical system of Example 2, following FIG.

FIG. 23 shows a specific example of a projection image of the maximum magnification on the screen at the time of long-distance projection of the zoom projection optical system of Example 2 according to FIG.
FIG. 24 shows a specific example of the projection image with the minimum magnification on the screen at the time of long-distance projection of the zoom projection optical system of Example 2 according to FIG.
"Example 3"
FIG. 25 shows a block diagram of a specific example 3 of the zoom projection optical system.

  As shown in FIG. 25, the refractive optical system 3 includes five lens groups and an aperture stop ST from the light valve 1 side on the reduction side toward the enlargement side.

  The five lens groups are a first lens group 3K, a second lens group 3L, a third lens group 3M, a fourth lens group 3N, and a fifth lens group 3O, arranged in the above order from the reduction side to the enlargement side. Yes.

  The first lens group 3K is composed of first to third lenses, and the second lens group 3L is composed of fourth to seventh lenses.

  The third lens group 3M is composed of an eighth lens to a tenth lens, and the fourth lens group 3N is composed of an eleventh lens and a twelfth lens.

  The fifth lens group 3O is composed of one thirteenth lens.

  Among these five lens groups, the fourth lens group 3N has “negative refractive power”, and the other four lens groups 3K, 3L, 3M, and 3O all have “positive refractive power”.

  The aperture stop ST is provided in the second lens group 3L. More specifically, it is formed on the reduction side surface of the fourth lens of the second lens group 3G.

  The first lens group 3K and the second lens group 3L constitute a “zoom group” that moves during zooming and performs zooming.

The third lens group 3M and the fourth lens group 3N constitute a focus group, and the fifth lens group 3O is a fixed group.
That is, the fifth lens group 3O does not move during zooming or when focusing.

  The first lens group 3K moves away from the light valve 1 when zooming to the high magnification side, and moves closer to the light valve 1 when zooming to the low magnification side.

  The second lens group 3L moves closer to the light valve 1 when zooming to the high magnification side, and moves away from the light valve 1 when zooming to the low magnification side.

  Therefore, the aperture stop ST provided in the second lens group 3L moves in the opposite direction to the first lens group 3K in conjunction with the first lens group 3L during zooming.

  When focusing from the short distance side to the long distance side, the third lens group 3M and the fourth lens group 3N move away from the light valve 1 as shown in the figure.

  The zoom projection optical system of Example 3 also has a concave mirror 4 having refractive power on the image side of the refractive optical system 3.

The mirror 4 is a “rotationally symmetric aspherical surface”, and its rotational symmetry axis is made coincident with the optical axis of the refractive optical system 3, and the position of (Y = 0, Z = 300.13) in the “YZ plane” of FIG. The vertex of the face is matched.

  The origin (Y = 0, Z = 0) of the YZ coordinate is the intersection of the optical axis of the refractive optical system 3 and the “image display surface” of the light valve 1.

  The data of the zoom projection optical system of Example 3 is shown in FIG.

  Further, FIG. 27 shows the lens interval data related to the zoom function and the focus function of the zoom projection optical system of Example 3 in accordance with FIG.

  Aspherical data is shown in FIG. 28 according to FIG.

  The numerical aperture on the object side is kept constant at 0.195 on both the enlargement side and the reduction side. That is, the numerical aperture is practically constant during zooming.

  A specific example of the light valve is shown in FIG. 29 following FIG.

  The light valve in FIG. 29 is the same as that shown in FIG. 7, but the distance between the optical axis of the refractive optical system and the “lower side in FIG. 25” of the image display surface of the light valve is shifted by 1.0 mm. ing.

  The light valve shown in FIG. 29 assumes a DMD having a diagonal length of 0.65 inches.

  The size and type of the light valve are not limited to this, and it may be a transmissive or reflective liquid crystal panel as in the case of the embodiment.

  Also, the shift amount between the optical axis and the lower side of the image display surface can be arbitrarily changed.

FIG. 30 shows a specific example of a projection image of the maximum magnification on the screen at the time of short distance projection of the zoom projection optical system of Example 3 according to FIG.
FIG. 31 shows a specific example of the projection image with the minimum magnification on the screen at the time of short-distance projection in the zoom projection optical system of Example 3 according to FIG.
FIG. 32 shows a specific example of the projection image with the maximum magnification on the screen at the time of the standard projection in the zoom projection optical system of Example 3 according to FIG.

  FIG. 33 shows a specific example of the projection image with the minimum magnification on the screen at the time of the standard projection in the zoom projection optical system of Example 2, following FIG.

FIG. 34 shows a specific example of the projection image of the maximum magnification on the screen during long distance projection of the zoom projection optical system of Example 3 according to FIG.
FIG. 35 shows a specific example of the projected image with the minimum magnification on the screen at the time of long-distance projection of the zoom projection optical system of Example 3 according to FIG.
FIG. 36 shows values of the focal lengths f1 to f5 of the lens units of Examples 1 to 3, the focal length f of the refractive optical system, and the parameter f1 / f of the condition (1).
All of Examples 1 to 3 satisfy the condition (1).

  In the zoom projection optical system of the present invention, the refractive optical system has a zoom function.

  During zooming with a zooming operation, the “lens group closest to the light valve” of the refractive optical system and the aperture stop move in conjunction with each other while changing the distance between them.

  The displacement of the lens group closest to the light valve and the aperture stop that moves while changing the distance between them can be adjusted so as to “reduce the change accompanying the magnification of the amount of light applied to the projection of the enlarged image”.

  As shown in the above-described embodiment, such adjustment can be performed so that the “light quantity applied to the projection of the enlarged image” does not substantially change during zooming.

  FIG. 37 is a diagram for describing one embodiment of an image display device.

  The image display device 200 is a projector device, and as the zoom projection optical system 100, the zoom projection optical system of the present invention, specifically, any one of the wave embodiments 1 to 3 is mounted.

  Any one of the first to third embodiments is used as the zoom projection optical system 100, and the zooming and focusing of the projected image can be realized with high accuracy while keeping the light amount constant during zooming.

  Of course, the image display apparatus 200 includes an illumination unit 101 for illuminating the light valve 1 and various circuit units 102 inside the apparatus.

  The window 103 from which the light beam is projected outside the apparatus housing may include a “cover glass”. At this time, the cover glass also plays a role of dust prevention.

1 Light valve
2 screens
3 Refraction optical system
4 Mirror with refractive power
ST Aperture stop
100 Zoom projection optical system

JP 2006-0787702 A JP 2010-122573 A JP 2010-122574 A

Claims (9)

In the zoom projection optical system that projects the image displayed on the light valve on the screen with variable magnification,
A refractive optical system having two or more lens groups and an aperture stop;
The refractive optical system has a zoom function;
A zoom projection optical system characterized in that, during zooming, the lens group closest to the light valve of the refractive optical system and the aperture stop move in conjunction with each other while changing the distance therebetween. The zoom projection optical system according to claim 1,
An aperture stop is provided in any of the second and subsequent lens groups from the light valve side,
A zoom projection optical system characterized in that, when zooming, the lens group closest to the light valve of the refractive optical system and the lens group provided with the aperture stop move in conjunction with each other while changing the distance between them. system. The zoom projection optical system according to claim 1 or 2,
A zoom projection optical system, characterized in that a mirror having refractive power is disposed between the refractive optical system and the screen. In the zoom projection optical system according to any one of claims 1 to 3,
A zoom projection optical system, wherein the lens group closest to the light valve of the refractive optical system moves in a direction approaching the light valve when zooming from a high magnification side to a low magnification side. In the zoom projection optical system according to any one of claims 1 to 4,
A zoom projection optical system in which an aperture stop moves in a direction opposite to a lens group closest to a light valve during zooming. In the zoom projection optical system according to any one of claims 1 to 5,
The refractive optical system has two or more lens groups that do not move during zooming,
A zoom projection optical system, wherein at least two lens groups out of two or more lens groups that do not move during zooming are focus groups. In the zoom projection optical system according to any one of claims 1 to 6,
The focal length for the e-line of the lens group closest to the light valve: f1, and the combined focal length for the e-line of the refractive optical system: f:
(1) 2.4 <f1 / f <6.2
Zoom projection optical system characterized by satisfying The zoom projection optical system according to any one of claims 1 to 7,
The refractive optical system is composed of five lens groups, and at least four of these lens groups have positive refractive power. An image display device for displaying an image displayed on a light valve on a screen by magnifying and projecting an image with variable magnification,
A light valve and a zoom projection optical system;
An image display apparatus using the zoom projection optical system according to claim 1 as the zoom projection optical system.

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