WO2008111591A1

WO2008111591A1 - Projection optical system, projector device, and image reading device

Info

Publication number: WO2008111591A1
Application number: PCT/JP2008/054431
Authority: WO
Inventors: Osamu Nagase; Yoshitsugu Kono
Original assignee: Ricoh Optical Industries, Co., Ltd.
Priority date: 2007-03-07
Filing date: 2008-03-05
Publication date: 2008-09-18

Abstract

It is possible to realize a novel projection optical system which can project a projection image of preferable quality on a large screen with a short entire length by combining a lens system and a concave mirror. The optical system enlarges and projects an image displayed on an image display surface IP onto a projection surface PS. The optical system includes a lens system L having a plurality of lenses and one or more curved mirrors. After emission of light from the lens system L toward the projection surface side, the light firstly comes onto the concave surface of the mirror surface MS of the curved mirror. The optical system satisfies the condition 20 < OAL/Y < 30, wherein OAL is a distance from the image display surface IP to the curved mirror surface nearest to the projection surface side along the optical axis shared by the largest number of lenses among optical axes of lenses constituting the lens system L, and Y is a distance up to the image display surface end portion farthest from the optical axis shared by the largest number of lenses within the image display surface IP.

Description

Specification

¾W optical system, projector device and image reading technology field

The present invention relates to an optical system, a projector apparatus, and a tw image reading apparatus. Background art

The optical system used in projectors is an optical system for enlarging and projecting an image displayed on a liquid crystal non-linear type, digital mirror device, etc., on a projection surface. Things are known.

Such an optical system must have long knock focus, high telecentricity of the incident light J of the enlarged imaging light beam, well-corrected chromatic aberration / distortion aberration, high MT F ½, and solution Etc. Power is required.

In addition, there is a strong demand for projectors with larger screens and smaller devices. A compact projector was realized as a rear projector using an optical system that combines a lens system and a concave mirror.

Japanese Patent Laid-Open No. 2 0 0 6-2 3 5 5 1 6

Those described in (1) are known. Disclosure of the invention

The invention is going to solve! ¾

The present invention is intended to realize a novel ¾l optical system that combines a lens system and a concave mirror and can produce a good ¾ image on a large screen while being short and full length.

The present invention also designates a projection optical system that can project a high-quality image on a large screen while having a short overall length, and in which ¾t is variable!

In addition, a compact projector and image reading using these projection optical systems will be realized.

Means for solving 1¾

1. The projection optical system according to the present invention is an optical system that projects an image displayed on the image display surface onto the surface. The image display surface is a surface on which an image to be enlarged is displayed. Specifically, the image display surface is a panel surface of a mold or a reflective liquid crystal panel, a mirror arrangement surface of a digital mirror device, or the like. The heel surface is a surface on which a heel image obtained by enlarging the image displayed on the image display surface is formed and projected, and is actually a model, a screen of a shape, or the like.

The optical system has a lens system and one or more curved mirrors.

The lens system has a plurality of lenses, and is positioned closer to the image display surface than one or more curved mirrors. '

The one or more curved mirrors have a concave or convex mirror surface, and are positioned on the carrying surface side of the lens system on the imaging optical path of the enlarged imaging light beam. That is, the expanded image-forming light beam from the image display surface is mfed by the one or more curved mirrors after being moved through the lens system, and is projected onto the t-plane. The enlarged image forming light beam is a light beam for forming an enlarged image.

Of the one or more curved mirrors, the mirror surface of the curved mirror that is initially the enlarged imaging light beam emitted from the lens system toward the projection surface is concave.

Since the number of curved mirrors is 1 or more, the minimum number of curved mirrors required is 1. Of the optical axes of the multiple lenses that make up the lens system, along the optical axis shared by the largest number of lenses, the OAL that extends from the image display surface to the curved mirror surface closest to the projection surface,

In the image display plane, the distance from the optical axis shared by the largest number of lenses to the edge of the most image display plane: Y is the condition:

(1) 2 0 <OA L / Y 3 0

Satisfied.

In other words, if the number of lenses constituting the lens system is n, all of these n lenses may share the optical axis, but the lens optical axes are deviated from each other, and the nl lenses are mutually optical. There can be multiple groups for each lens sharing the optical axis, such as n two lenses sharing the optical axis with each other. This ^^, even if there is only one lens in each group, at least one of the gnoles includes multiple lenses.

Among these groups, the optical axis shared by the lenses of the group including the largest number of lenses is the optical axis shared by the largest number of lenses. If there are multiple groups that contain the largest number of lenses, that is, if there are two or more groups that share the same number of lenses sharing the optical axis, then Y is the largest Y among these groups. Shall be said. O: OAL extends from the image display surface to the most surface side of the image display surface, which is developed by extending the optical axis, which is formed by the lens at the maximum position, to the image display surface side and the υ¾ projection surface side. It is the length to a mirror surface of a curved mirror, and when this B_h includes a ¾¾ί (color synthesis prism, etc.) that has no bending force between the image display surface and the lens system, this physical The value obtained by dividing the thickness by the refractive index of the e-line is used for the calculation of «: OAL.

2. The optical system described in 1 above can change the screen size of the Si image on the surface. ^^ When changing the screen size, the image forming surface forms an expanded image beam. The optical path is also kept constant to the mirror surface of the curved mirror with ltL, and according to the change in the distance from the mirror surface to the surface of the most curved mirror, the image display surface and the curved mirror with the most It is possible to change the position of some or all of the optical elements between the mirror surface.

Here, the optical element is each of a plurality of lenses constituting the lens system and one or more curved mirrors.

3. In the lens system in the projection optical system described in 1 or 2 above, all the lenses constituting the lens system can share the optical axis. Of course, in this ^^, the lens system itself has a single optical axis, and this single optical axis is the optical axis shared by the above-mentioned most lenses.

4. In the carrying optical system described in any one of 1 to 3 above, it is preferable that the numerical aperture on the image display surface side is larger than 0.25.

5. In the projection optical system described in any one of 1 to 4 above, the negative lens located closest to the image display surface among the negative lenses included in the lens system has a surface on the image display surface side. It is preferably in contact with air and having a concave shape on the image display surface side.

6. The optical system described in any one of 1 to 5 above preferably has an aperture stop between the lens on the image display surface side and the lens on the most ¾ | † surface side in the lens system. .

7. The positive lens located closest to the image display surface among the positive lenses included in the lens system of the projection optical system described in any one of 1 to 6 above is the refractive index for the e-line of the lens material. : NPe force Condition:

(2) 1.45 <nPe <1.65

Is preferably satisfied.

8. The curved mirror with the imaging optical path on the carrying surface side of the optical system described in any one of the forces 1 to 7 described above has an optical axis shared by many lenses in the lens system. ^ And It is preferable that the surface be an axial surface. This ^^ is also the optical axis that gives the "maximum Y" when there are multiple optical axes shared by the largest number of lenses.

9. The optical system described in any one of 1 to 8 above has an aperture stop between the lens closest to the image display surface and the lens closest to the projection surface in the lens system. Refractive index at the e-line of the lens material of each spherical negative lens (negative lens with a spherical lens surface) positioned between the aperture stop and the curved mirror: n N e force condition

(3) 2. 0> n N e> 1. 6 5

Is preferably satisfied.

1 0. In the optical system according to any one of 1 to 9, the number of curved mirrors can be one.

Of course, the carrying optical system described in any one of 1 to 10 above can have one or more plane mirrors for bending the imaging optical path in the optical path according to actual use conditions.

1 1. A projector device according to the present invention is a projector device equipped with the Si optical system according to any one of the above 1. K. et al.

1 2. In addition, the image reading apparatus of the present invention uses the carrying device described in any one of the above 1. Force 1 0. as a reduction optical system, and places the light receiving surface of the image sensor at a position to be an image display surface. This is an image reading apparatus that is arranged and captures an image.

It goes without saying that an image recording apparatus can be configured by adding a recording unit that indicates image information read by the image reading apparatus. Note that the position where the light receiving surface of the image sensor is arranged should be the image display surface, not only the position that fits the image display surface, but also the position equivalent to the image display surface, that is, the connection of the reduction optical system. ^: The image position of the reduction optical system can be any position, and both the image display surface and the image sensor can be provided.

The carrying optical system of the present invention is an optical system having a short overall length, but projects a large screen.

As a matter of course, in a projection optical system using only ordinary lenses, the total lens length is almost determined by the F picker and half angle of view.

The projection optical system of the present invention has a curved mirror mirror set in the lens system. However, the »-like part has many in common with the property of the lens only, and the image display range on the image display surface increases. That is, the larger the value of Y mentioned above, the more difficult it is to secure the performance. To secure the performance, it is necessary to increase the total length of the optical system (the aforementioned distance: approximately OA L). It becomes good for the time.

Condition (1) is a condition for ensuring performance and taking the balance of the total length of the optical system that determines the overall size. Parameter: When OA LZY is smaller than the lower limit, “how large the total length” is. However, the image plane is not uniform and sufficient performance as an optical system cannot be secured. Also, if the optical parameter: OA LZY exceeds the upper limit of condition (1), the optical system becomes long, and the optical path is bent by a flat mirror, etc., as in the optical system of a rear projection television. Otherwise, it will be difficult to use.

The optical system of the present invention can be used for both a rear projector and a front projector, but it is used for a front projector ^, like the projection optical system described in 2. above, a screen (projection) that projects an image from the projection optical system. The image size can be changed by changing the distance to the screen.

In this case, in contrast to the so-called focusing, the change in the image plane and the distortion of the screen outline caused by the image size change are mainly projected on some lenses and all lenses depending on the lens configuration. It can be corrected by moving it according to the change in distance.

The same effect is obtained by changing the position of the curved mirror that is the most mt from the image display surface relative to the image display surface. Therefore, high accuracy is required. There is also a need to accompany the movement of lighting systems such as lamps.

The curved mirror closest to the projection surface on the imaging optical path is inevitably large, leading to an increase in the size of the movable part for moving the large curved mirror, increasing the size of the entire system, and increasing costs. Leads to.

For this reason, to change the image size, move some or all of the lenses included in the lens system to correct image plane tilt and distortion of the screen outline when SliSgi changes. It is good.

In addition, by decentering some lenses in the lens system with respect to other lenses, the degree of freedom of component placement can be increased and the function can be improved. However, the lens is deflected by an exact amount. In some cases, it is more difficult to align the lenses than aligning the lenses.

The lens system of the projection optical system of the present invention also shares a unique optical axis, that is, stable performance can be ensured by not decentering each lens, but the condition (1) must be satisfied. This ensures performance even when the lens is decentered. Further, when the projection optical system of the present invention is used for a front projector, the optical system needs to be a bright optical system so that a portable image can be recognized even in a bright place. By making the numerical aperture on the side larger than 0.25, a bright optical system can be achieved.

The curved mirror on the most magnified image side (curved mirror closest to the surface in the imaging optical path) that greatly contributes to image performance is less likely to cause a difference in properties depending on the direction if it has an axial shape. Although there is an advantage that the aspect ratio can be easily maintained, it is also effective to use an axially asymmetric surface, a so-called free-form surface, in order to obtain a certain level of resolution and distortion. The lens system of the optical system according to the present invention is practically composed of a lens system having a rotationally symmetric lens surface, and has a strong positive power as a whole lens unit. In order to use the oblique light beam as the enlarged image light beam, the screen system tilts the enlarged image surface to the back of the screen. This tilting of the magnified image plane can be corrected by pulling the magnified image plane back to the front of the screen with a concave curved mirror. However, it is mainly the so-called meridian image plane that is corrected flatly by such correction, and the so-called spherical image plane tends to be undercorrected. As in the case of the carrying optical system described in 5. above, the surface on the image display surface side of the negative lens located closest to the image display surface is in contact with air having a large refractive index difference from the lens material, and By making the shape concave toward the image display surface, it is possible to compensate for insufficient correction of the spherical image surface without significantly affecting the meridian image surface.

In addition, as in the optical system described in 6. above, various apertures can be corrected in a balanced manner by providing an aperture stop between the lens on the image display surface 彻 J and the lens closest to the projection surface. It is.

Condition (2) to be satisfied by the projection optical system described in 7. above is a condition for ensuring uniformity of the image plane. When the upper limit is exceeded, the image plane is closer to the projection plane (screen) than the projection plane (screen). If the image falls below the lower limit, the image plane will fall to the back of the ¾ t plane.

The condition (3) to be satisfied by the projection optical system described in 9 above is to ensure the uniformity of the image plane. In the case of a normal projection system having only a lens, it is ideal to use a material with a low refractive index for the negative lens in order to reduce the Petzval sum. On the other hand, since the balance with the curvature of field generated by the curved mirror is balanced, it is advantageous to improve the performance by using a material having a large refractive index for the negative lens.

If the lower limit of condition (3) is exceeded, the image plane will be at the back of the screen. It will be on the near side of the clean and it will be difficult to correct with other factors.

A plurality of curved mirrors may be used as long as they do not obstruct the optical path. By using a plurality of curved mirrors, it is possible to obtain a better image by dispersing or canceling the generation of the convergence.

In addition, the projection optical system of the present invention uses S ^ as the front projection for observing ¾f light using the S screen, but for rear projection using ¾1 ^ 1 "from the back of the screen using the mold screen. Can also be used.

The ¾ | † optical system of the present invention can also be used as a reduction optical system by arranging a light receiving element such as a CCD or CMOS at a position on the image display surface or a position i i from the image display surface. Lean) It is also possible to use the image reading apparatus for capturing image information at a position.

The invention's effect

As described above, according to the present invention, in spite of a short total length of the optical system, the projection optical system has little distortion in the projected image, has a high resolving power, and is capable of ¾ # ί on a large screen. An optical system capable of changing the surface size can be realized, and a projector apparatus using a large projection optical system and image reading can be performed.

Brief Description of Drawings

FIG. 1 is a diagram showing an embodiment of a projector apparatus.

FIG. 2 is a diagram showing a specific example (Example 1) of the projection optical system in the embodiment of FIG. FIG. 3 is a spot diagram for the 78 inch projection of Example 1.

FIG. 4 is a spot diagram at the time of 64 inch projection in Example 1.

FIG. 5 is a diagram showing another embodiment of the projector apparatus.

FIG. 6 is a diagram showing a specific example (Example 2) of the projection optical system in the embodiment of FIG. FIG. 7 is a spot diagram at the time of 78-inch projection in Example 2.

FIG. 8 is a spot diagram of Example 2 at the time of 64 inch projection.

FIG. 9 is a diagram showing another embodiment of the projector apparatus.

FIG. 10 is a diagram showing a specific example (Example 3) of the projection optical system in the embodiment of FIG. FIG. 11 is a spot diagram at the time of 78-inch projection of the third embodiment.

FIG. 12 is a spot dyaram at the time of 64 inch projection in the third embodiment.

FIG. 13 is a diagram showing another embodiment of the projector apparatus.

FIG. 14 is a diagram showing a specific example (Example 4) of the projection optical system in the embodiment of FIG. FIG. 15 is a spot diagram when projecting 100 inches according to the fourth embodiment.

FIG. 16 is a spot diagram at the time of 70-inch projection in Example 4.

FIG. 17 is a spot diagram when carrying 50 inches according to the fourth embodiment.

Explanation of symbols

I P • IS image table missing

P: Prism

L: Lens system

S: Aperture stop

MS: Mirror surface

P S: Projection surface

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the invention will be described.

FIG. 1 is a diagram showing an embodiment of a projector apparatus.

In the figure, symbol IΡ indicates an image display surface, symbol Ρ is a prism, symbol L is a lens system, symbol MS is a mirror surface of a curved mirror ¾T surface, and symbol PS is a screen surface that is a surface. Show.

Specifically, the image display surface IP is, for example, a non-i-type or mirror liquid crystal panel, a mirror arrangement surface of a digital mirror device, or the like.

The prism P is a prism such as a color synthesis prism. The lens system L includes a plurality of lenses.

S is located on the screen surface PS side, which is the third plane, on the imaging optical path, and is concave on the lens system L side. In this embodiment, all the lenses included in the lens system L share the optical axis.

As shown in FIG. 1, the image display surface IP is shifted downward in the figure with respect to the optical axis shared by all the lenses of the lens system L. Therefore, in FIG. 1, the 賺 between the optical axis of the lens system L and the lower end of the image display surface I P is 赚: Y.

Since the image display surface IP is thus shifted with respect to the optical axis of the lens system L, the projection optical system is an off-axis optical system that forms an image of a so-called oblique). The image displayed on the image display surface IP is enlarged and projected onto the screen surface PS as shown in the figure by the imaging action of the lens system L and the reflection mirror MS of the curved mirror.

FIG. 2 is a diagram showing a configuration of a specific example of the projection optical system in the embodiment shown in FIG. is there. S indicates a diaphragm provided in the lens system L.

The data of the optical system shown in Fig. 2 is shown below as Example 1. The meanings of the symbols in the data are as follows. The same applies to Examples 2 to 4 described later.

i The i-th surface from the image display surface side (prism surface lens surface diaphragm surface reflection surface)

IMG screen surface

R i Curvature of the i-th surface from the image display side ^ S

D i Distance from the i-th surface to the i + 1-th surface counted from the image display surface side D o IM from the image display surface to the first surface

J Lens number counted from the image display side

N j Refractive index ^ T on the d-line of the j-th lens from the image display side

V j Abbe number of the j-th lens from the image display side

The surface marked with (*) indicates a rotated * fl¾ ^ spherical surface.

The surface with (#) indicates that it is a free-form surface.

Unless otherwise noted, the amount of eccentricity of the lens and mirror is zero.

Rotational symmetry The spherical shape is: optical axis direction coordinate: _z , optical axis orthogonal direction coordinate: h, on-axis curvature radius: R i, conic constant: K, coefficient: A, B, C, D, E, Well-known formula by F, G:

z = (1ZR i) · h ² Z [l + ^ {1— (K + l)-(1 / R i) ² · h ² }]

+ A · h ⁴ + B · h ⁶ + C · h ⁸ + D · h ¹⁰ + E · h ¹² + F · h ^, + G · h ¹⁶

Is represented by

The shape of the free-form surface is as follows: screen horizontal coordinate: χ, vertical coordinate: y, X, y coordinate orthogonal to both directions: z, on-axis radius of curvature: R i, elliptic constant: K, coefficient: Using C j (j = 2 to 66), the following formula:

z = (1 / R i) · h z il + {1- (K + l) · (l / Ri) ² · h ² }]

+ ∑C j x ^m y ⁿ

Where j = [(m + n) ² + m + 3 n] / 2 +1

Is represented by

The calculation reference wavelength is 550 nm (^ fe).

Example 1

i R D j N V

0 ∞ 10.400 1 27.500 1.51680 64.2

2 ∞ variable

3 90.67541 11.466 1 1.61800 63.4

4 -36.32076 4.051

5 29.82045 4.500 2 1.48749 70.4

6 989.57270 4.312

7 -24.04669 1.800 3 1.75520 27.5

8 19.38336 5.800 4 1.49700 81.6

9 -121.56068 2.680

10 62.28636 7.972 5 1.59270 35.5

11 -24.68738 0.300

12 32.12683 1.500 6 1.80610 40.7

13 21.27498 1.834

14 21.72845 6.909 7 1.59270 35.5

15 962.64456 1.172

16-98.83816 1.500 8 1.77250 49.6

17 39.40166 2.076

18 (Aperture) ∞ 19.418

19 83.27478 6.299 9 1.58144 40.9

20 -343.22066 Variable

21 52.99491 6.439 10 1.80610 33.3

22 107.31174 11.198

23 -23.64924 2.275 11 1.69895 30.1

24 -44.35174 Variable

25 (*) -31.88842 5.500 12 1.53046 55.8

26 (*) 0.374805E-7 Variable

27 (#)-75.12400 Variable (Mira-surface)

IMG OO 0.0

The 25th surface is a rotating spherical surface, and the coefficients are as follows.

K = -0.647409 A = -0. 216474E-06, B = 0. 125574E-08, C = 0. 145745E-13, D = 0.0, E = 0, F = 0, G = 0 The coefficients are as follows.

K = -0. 336961E + 22

A = -0. 102806E-04, B = 0. 272899E ~ 08, C = ~ 0. 197767E-11, D = 0.0, Ε = 0, F = 0, G = 0 The coefficients are as follows.

Κ = -1. 0

C7 =-1. 0688E-05, C8 = -l. 2005E ~ 05, C9 = -4. 4146E-06, C10 =-1. 2968E-05

Cll = 7. 7094E-08, C12 = 2. 0953E ~ 07, C13 = 2. 3356E-07, C14 = 7. 2321E-08

C15 = 1. 5468E-07, C16 = 1. 0049E ~ 09, C17 =-3. 7655E-10, C18 =-6. 1907E-10

C19 = -3. 1177E-10, C20 = 6. 3132E-12, C21 = 2. 6661E-10, C22 =-1. 1863E-11

C23 =-8. 1479E-12, C24 =-2. 0740E-11, C25 =-4. 6813E-12, C26 =-2.2 1414E-11

C27 = -3. 1925E_12, C28 = _l. 0867E-11

C2 to C6 and C29 to C66 are 0.

In the above notation, for example, [E ~ 05] represents [X 1 0 " ⁵ ]. The same applies to the following.

Surface size

78 inches 6 4 inches

D2 0. 200 0. 332

D20 1. 255 0. 300

D24 17. 706 17. 874

D26 173. 957 174. 612

D28 (Projection -494. 000 -416. 070

A = 0.25 on the image display side

0AL = 329. 62 Y = 12.5

Parameter value for condition (1): 26.7

Parameter value for condition (2): 1. 620

Parameter values for condition (3): 1. 704 (1st 1st lens Ne).

FIG. 3 shows a spot diagram on the screen surface PS of the first embodiment.

The spot diagram in Figure 3 shows an image ratio of 4: 3 and a diagonal length of 0.6 inch when the image on the LCD panel is enlarged to a diagonal length of 78 inches on the screen. of Is.

FIG. 4 shows a spot diagram on the screen surface PS of Example 1.

The spot diagram in Fig. 4 shows the image ratio of 4: 3 and diagonal length: 0.6 inch, when the image of the image display surface of a liquid crystal nonel is enlarged on the screen to a diagonal length of 6 4 inches. belongs to.

The values of port IJ in Fig. 3 are the X and y coordinates on the corresponding image display surface.

For example,

X 6. 1 5 y 1 0.9

There is

X = 6. 1 5 mm, y = 1 0.9 mm

Means. The same applies to FIG. 4, FIG. 7, FIG. 8, FIG. 11, FIG. 12, FIG. 15, FIG.

FIG. 5 is a diagram showing another embodiment of the projector apparatus. In order to avoid this problem, the same reference numerals as those in Fig. 1 are assigned to those that are not likely to be confused.

As in the embodiment of FIG. 1, in the embodiment of FIG. 5, all lenses share the optical axis in the lens system L.

As shown in FIG. 5, the image display surface IP is shifted downward in the figure with respect to the optical axis shared by all the lenses of the lens system L. Therefore, in FIG. 5, S¾ | between the optical axis of the lens system L and the lower end of the image display surface I P in the figure is a distance: Y.

Thus, since the image display surface IP is displaced with respect to the optical axis of the lens system L, the projection optical system is an off-axis optical system that forms a so-called oblique image. The image displayed on the image display surface IP is magnified as shown in the figure and imaged on the screen surface PS by the image forming action of the lens system L and the reflection mirror EMS of the curved mirror.

FIG. 6 is a diagram showing the configuration of a specific example of the projection optical system in the embodiment shown in FIG.

The optical system data shown in FIG. 6 is shown as Example 2 below.

Example 2

i R D j N v

0 ∞ 10. 800

1 ∞ 29. 200 1. 51680 64. 1

The 28th surface is a rotating sphere, and the coefficients are as follows.

K = 14. 722645

Α = 0. 419885Ε ~ 05, Β = 0.297558Ε-08, C = -0. 637756E-11, D = 0. 465514E-14

E = ~ 0.123269E-17, F = 0, G = 0

The 29th surface is a rotating ¾ · ^ aspherical surface, and the coefficients are as follows.

K = -200. 000

Α = -0. 397967Ε-05, B = 0. 401039E-O8, C = "0. 454979Ε- 11, D = 0. 251307E-14

E = ~ 0.425185E-18, F = 0, G = 0

The 30th surface is a rotating sphere, and the coefficients are as follows.

K =-2. 360048

Α = -0. 274563Ε-06, B = 0. 161310E-10, C = -0. 114777E-14, D = 0. 291873E-19

E = 0. 140965E— 23, F = -0. 184116E— 27, G = 0. 546153E-32

Variable part value

魏 Screen size

78 inches 6 4 inches

D21 24. 494 22. 999

D23 8. 310 8. 760

D27 6. 326 6. 107

D29 170. 000 171. 264

D30 (髓赚) 493. 000 -415. 670

NA on image display side = 0.27

0AL = 355. 027 Υ = 16

Parameter value for condition (1): 21.9

Parameter value for condition (2): 1. 498

Parameter values for condition (3): 1 · 839 (12th lens Ne), 1. 839 (13th lens Ne). FIG. 7 shows a [spot diagram] on the screen surface PS of Example 2. The spot diagram in Fig. 7 shows an image of an LCD panel with an aspect ratio of 4: 3 and a diagonal length of 0.78, and is enlarged on the screen to a diagonal length of 78 inches. is there.

FIG. 8 shows a [spot diagram] on the screen PS of Example 2. The spot diagram in Fig. 8 shows an aspect ratio of 4: 3 and a diagonal length of 0.7. When the image on the image display surface of an 8-inch LCD panel is enlarged on the screen to a diagonal length of 6 4 inches. belongs to.

As shown in the spot diagrams of FIGS. 3 and 4 and the spot diagrams of FIGS. 7 and 8, all the carrying optical systems of Example 2 have good performance.

FIG. 9 is a diagram showing another embodiment of the projector apparatus. In order to avoid this problem, the same reference numerals as those in FIG.

As in the embodiment of FIG. 1, in the embodiment of FIG. 9, in the lens system L, all lenses share the optical axis.

As shown in FIG. 9, the image display surface IP is shifted downward in the figure with respect to the optical axis shared by all the lenses of the lens system L. Therefore, in FIG. 9, the distance between the optical axis of the lens system L and the lower end of the image display surface IP in the figure is «: Y.

Since the image display surface IP is thus deviated with respect to the optical axis of the lens system L, the optical system is an off-axis optical system that forms a so-called oblique image. The image displayed on the image display surface IP is enlarged as shown in the figure and imaged on the screen surface PS by the lens system L and the image forming action of the curved mirror ^ tffiMS.

FIG. 10 is a diagram showing the configuration of a specific example of the projection optical system in the embodiment shown in FIG.

The data of the projection optical system shown in FIG.

Example 3

1 R D J N V

0 CO 0. 500

1 oo 27. 000 1. 51680 64. 2

2 oo 0. 300

3 243. 39589 7. 876 1 1. 61800 63.4

4 -36. 80043 11. 415

5 38. 29383 4. 437 2 1. 48749 70. 4

6 -270. 48389 2. 620

7 -27. 82599 2. 000 3 1. 75 520 27. 5

8 25. 99933 5. 787 4 1. 49700 81. 6 9 -83. 09026 6. 394

0 64. 09770 10. 000 5 1. 59270 35. 51 -34. 66611 7. 002

2 (Aperture) ∞ 8. 461

3 -144. 06734 10. 000 6 1. 75 136 30. 44 -47. 22642 1. 885

5 -29. 11230 10. 000 7 1. 84666 23. 86 -51. 94609 41. 000

7 97. 21127 9. 964 8 1. 81305 40. 68-502. 02314 35. 220

9 -37. 09509 10. 000 9 1. 69895 30. 10-476. 03001 Variable

1 (*) -72. 82677 6. 600 10 1. 53046 55. 82 (*) -237. 58519 Variable

3 (#) -10000. 000-530. 000 (reflective surface)

IMG oo 0. 000

The second surface is an axial sphere, and the coefficients are as follows.

K = -16. 266645

A = 0.120791E-05, B = ~ 0.218628E-09, C = 0.199306E-13 The second 2nd surface is an axial sphere, and the coefficients are as follows.

K = -500. 0

A = -0. 219810E-05, B = -0. 388265E-09, C = 0.1118932E-12 The second 3rd surface is a free-form surface, and its coefficients are as follows.

K = -9. 7635Ε 03, C4 = -5. 9146E-03, C6 = -5. 7109E-03

C8 = 1. 3364E-06, C10 = -1. 8655E-05 Cll = 2. 1404E-10

C13 = -2. 0400E-07, C15 = 8. 1614E-07, C17 = -6. 5598E-11

C19 = 1. 087 E-08 C21 = -2. 0546E-08, C22 = -9. 8347E- 13 C24 = 3. 2450E-11 C26 = -3. 2424E-10, C28 = 3. 0791E-10 C30 = 6. 5044E-15 C32 = -1 3436E-12, C34 = 6. 5082E-12 C36 = -2. 6129E— 12 C37 = -2. 0976E-16, C39 = -3. 7751E-15 C41 = 1. 2508E-14 C43 = -8. 7230E-14, C45 = 9. 2980E-15

C47 = 2. 3106E-18 C49 = 1. 1024E-16, C51 = -3. 4790E-18

C53 = 6. 4308E-16 C55 = 1. 1821E-17, C56 = 7. 3701E-22

C58 = -7. 9731E-20 C60 = -8. 3892E-19, C62 = -3. 1803E-19

C64 = -1. 9714E-18 C66 = -1 3557E-19

In the above, the value of the aspherical coefficient and the coefficient of the free-form surface not specifically described are “0”. The same applies to Example 4 to be described later.

Variable part value

Screen size

78 inches 6 4 inches

D S2 0. 300 0. 333

D S20 13. 527 13. 885

D S22 176. 414 176. 022

D S23 -530. 000 -448.461

NA on the image display side: 0.29

0AL = 408.4

Object size y (straight direction) = 2. 2 to 1 4

(Horizontal direction) = — 8 to 8

Parameter value for condition (1): 25. 3,

Parameter value for condition (2): 1. 62032

Condition (3) value 1. 8550 (7th lens Ne) 1. 7044 (9th lens Ne)

Figure 11 shows a spot diagram on the screen surface PS of Example 3. The spot diagram in Fig. 1 shows an image of the image display surface of a liquid crystal panel with an aspect ratio of 4: 3 and a diagonal length of 0.78 inches, and a diagonal length of 78 inches on the screen. It is the one when enlarged to.

Figure 12 shows a spot diagram on the screen P S of Example 3. The spot diagram in Fig. 1 shows that the image of the image display surface of a liquid crystal panel with an aspect ratio of 4: 3 and a diagonal length of 0.78 inches was enlarged to a diagonal length of 64 inches on the screen. It's time.

FIG. 13 is a diagram showing another embodiment of the projector apparatus. To avoid Those that are considered not to have the same fear V are given the same reference numerals as in FIG.

In the embodiment shown in FIG. 13, in the lens system, the lens on the object side of the diaphragm S has an optical axis, and the lens on the image side of the diaphragm S also shares the optical axis. The optical axes shared by the lenses on both sides of the aperture do not coincide with each other, and the optical axis of the reflecting surface is also deviated from the optical axis shared by the lenses on the object side of the aperture S. The optical axis shared by is the optical axis shared by the lens arranged on the object side of the stop S.

As shown in FIG. 13, the image display surface I P is shifted downward in the figure with respect to the optical axis shared by the lens on the object side of the diaphragm S. Therefore, in FIG. 13, the 赚 between the optical axis shared by the object-side lens of the diaphragm S and the lower end of the image display surface I P is ある: Y. Thus, since the image display surface IP is shifted with respect to the optical axis shared by the lens on the object side of the diaphragm S, the projection optical system is a so-called off-axis optical system that forms an image of oblique rays. It has become. The image displayed on the image display surface I P is enlarged as shown in the figure and formed on the screen surface P S by the lens system L and the StffiM S imaging function of the curved mirror.

FIG. 14 is a diagram showing the configuration of a specific example of the projection optical system in the embodiment shown in FIG.

The data of the projection optical system shown in Fig. 14 is shown as Example 4 below.

Example 4

1 R D J N V

0 ∞ 10. 400

1 oo 27. 500 1. 51680 64. 2

2 oo 0. 000

3 221. 99060 5. 263 1 1. 51823 59. 0

4 -43. 32818 2. 131

5 427. 39205 3. 276 2 1. 51823 59. 0

6 -91. 87051 0. 300

7 48. 81452 4. 105 3 1. 48749 70. 4

8 -208. 55401 1. 560

9 -44. 36637 1. 600 4 1. 83400 37.3

10 43. 27898 5. 051 5 1. 49700 81. 6

11 -49. 78687 0. 300 12 29. 00567 5. 480 6 1. 48749 70. 4

13 -74. 96679 8. 863

14 -58. 28332 1. 400 7 1. 83400 37. 3

15 23. 44971 3. 790 8 1. 48749 70. 4

16 153. 56 154 6. 358

17 -331. 82123 3. 304 9 1. 84666 23. 8

18 -40. 46769 0. 371

19 (Aperture) OO variable

20 63. 89415 19. 060 10 1. 51680 64. 2

厶 Y = 5. 000

21 -53. 28671 Variable

22 (*)-312. 79326 5. 500 11 1. 53046 55.8

23 (*) -98. 78860 7. 165

24 (*) -59. 26451 5. 000 12 1. 53046 55.8

25 (*) 26. 71955 Variable

26 169. 96226 3.000 13 1. 83400 37. 3

27 52. 43843 pj strange

28 (*) -69. 59940 Variable projection surface)

厶 Υ = -5. 000

IMG ∞ 0. 000

The second 2nd surface is an axis and an aspheric surface, and the coefficients are as follows.

K = 0. 000000

A = -0. 258176E-04, B = 0. 862854E-08, C = 0. 593441E-11, D = ~ 0. 327956E-14 The second 3rd surface is the axis ^ sphere, and the coefficients are as follows is there.

A = -0. 525113E-05, B = 0. 674453E-08, C = -0. 450 325E-11, D = 0. 130656E-14 The second 4th surface is an axis ¾ ^ sphere, and the coefficients are as follows It is.

K = -4. 027985

A = 0. 115837E-04, B = -0. 915031E-09, C = -0. 826204E-11, D = 0.449270E-14 E = 0. 129610E-17, F = -0. 198992E-20, G = 0. 310917E-24 The second 5th surface is an axis ¾ ^ sphere and the coefficients are as follows:

K = -6. 045148

A = ~ ϋ. 126937E-04, = 0 = 0. 107777E-07, C = -0. 459001E-11 D = -0. 108 169E-14 E = 0. 630308E-18, F = 0. 683893E-21, G = -0. 451435E-24

The second 8th surface is an axis ¾ ^ aspherical, and the coefficients are as follows: _c

K = -2. 751902

A = -0. 552112E-06, B = 0. 704592E-10, C = -0. 740927E-14 D = 0. 173827E-18 E = 0. 399460E-22, F = -0. 390960E-26, G = 0. 981348E- 31

厶 Y represents the amount by which the center of the surface is shifted in the Y direction (, direct direction), and the subsequent surfaces follow it.

Variable part value

Screen size

100 inch 70 inch 50 inch

D S19 71. 548 70. 481 69. 002

D S21 6. 640 6. 604 6. 534

D S25 3. 086 3. 468 4. 092

D S27 154. 000 154. 718 155. 646

D S28 -623. 000 -449. 269 -333. 195

表示 on the image display side: 0.27

0AL = 366. 05

Object size y (vertical direction) = 1.9

X (horizontal direction) = —6.

Parameter value for condition (1) 27. 81

Value of parameter for condition (2) 1. 52033

Value of parameter in condition (3) 1. 83930 (for 13th lens)

Fig. 15 shows a spot diagram on the screen surface PS of Example 4. The spot diagram in Fig. 15 shows an image of the LCD panel with an aspect ratio of 4: 3 and a diagonal length of 0.78 inches, and is enlarged on the screen to a diagonal length of 100 inches. belongs to.

Fig. 16 shows a spot diagram on the screen PS of Example 4. The spot diagram in Figure 16 shows an image on the LCD panel with an aspect ratio of 4: 3 and a diagonal length of 0.7.8 inches, and a diagonal length of 70 inches on the screen. It is a thing when you do.

Fig. 17 shows a spot diagram on the screen surface PS of Example 4.

The spot diagram in Fig. 17 shows an image of the image display surface of a liquid crystal nonel with an aspect ratio of 4: 3 and a diagonal length of 0.78 on the screen enlarged to a diagonal length of 50 inches. It is a thing.

In other words, the projection optical systems of Examples 1 and 4 have little distortion, high resolution, high-capacity transport, and variable projection image screen size, despite the short overall length of the optical system. it can. The projection optical system of the first embodiment, et al. 4 is an optical system that enlarges and projects an image displayed on the image display surface IP onto the projection surface PS, and includes a lens system L having a plurality of lenses, and one or more The first mirror surface MS of the curved mirror that is Λΐί after exiting from the lens system L to the surface PS side is concave, and the optical axis of the plurality of lenses constituting the lens system L Along the optical axis shared by many lenses, from the above image display surface to the curved mirror surface closest to the projection surface! «: OA L, image display surface IP, shared by the largest number of lenses Distance from the optical axis to the edge of the image display surface that is the most li l: Y

(1) 20 0 OA L / Y 3 0

Satisfied.

In addition, the projection optical system of these examples has a variable screen size of the projection image on the Fuji surface PS. When changing the screen size, the image display surface IP and the image forming optical path from this image display surface ± ¾ Some optical elements are located between the image display surface and the mirror surface according to the change in the distance from the mirror surface MS to the projection surface PS. The position of is changed.

In the projection optical systems of Examples 1 to 4, all the lenses constituting the lens system L share the optical axis, and the numerical aperture on the image display surface side is larger than 0.25.

In the projection optical systems of Examples 1 to 4, among the negative lenses included in the lens system L, the negative lens located most on the image display surface side (j = 3, j = 4 in Example 4) The surface on the display surface side is in contact with air and has a concave shape on the image display surface side. Further, in the lens system L, an aperture stop S is provided between the lens closest to the image display surface and the lens closest to the projection surface.

In addition, among the positive lenses included in the lens system L, the positive lens located on the “most image display surface side” (j = 1) Refractive index at the e-line of the lens material: n Pe force Condition (2) is satisfied, and the mirror surface MS of the curved mirror closest to the projection surface in the imaging optical path is This is an axial plane with the optical axis shared by the largest number of lenses as ¾.

Embodiment 1 Both the ¾ t optical system of 4 and the like have an aperture stop S from the lens closest to the image display surface to the lens on the most ¾ surface side in the lens system L, and this aperture stop to the curved mirror For each spherical negative lens positioned between 1 and 2, the refractive index for the e-line of the lens material: n N e satisfies the condition (3). And there is one curved mirror.

In addition, in the optical arrangement of Fig.1, Fig.5, Fig.9 »Fig.13, the original is placed on the screen surface PS position, and the light receiving surface of the image sensor at the image display surface position or equivalent to the image display surface position If the projection optical system is used as a reduction optical system, image reading using the carrying optical system can be realized. Industrial applicability

As described above, the projection optical system of the present invention is useful as a projection optical system capable of projecting a high-quality projection image on a large screen while having a short length and a full length, and is suitable for use as a projector in an image reading apparatus. .

Claims

The scope of the claims

1. An optical system for enlarging and projecting an image displayed on an image display surface on a surface, having a lens system having a plurality of lenses, and one or more curved mirrors,

The magnified imaging light beam emitted from the lens system toward the ¾ † surface side is the turning surface of the mirror surface of the curved mirror that first Alts,

OA L from the image display surface to the curved mirror surface closest to the projection surface, along the optical axis shared by the most lenses among the optical axes of the plurality of lenses constituting the lens system, the image Within the display surface, the distance from the optical axis shared by the many I2S lenses to the edge of the image display surface that is the most 1¾τ: Y: Condition:

(1) 2 0 <OA L / Y <30

An optical system that satisfies the following.

2. The screen size of the projected image on the projection surface is variable,

When changing the screen size, the image display surface and the distance from the image display surface to the mirror surface of the curved mirror separated from the imaging optical path _h¾ are kept constant,

The position of some or all of the optical elements located between the image display surface and the mirror surface is changed in accordance with a change in the distance from the mirror surface to the projection surface. The jump optical system according to item.

3. The projection optical system according to claim 1, wherein all lenses constituting the lens system share an optical axis.

4. The optical system according to any one of claims 1 to 3, wherein the numerical aperture on the image display surface side is larger than 0.25.

5. Among the negative lenses included in the lens system, the negative lens located closest to the image display surface is such that the image display surface side is in contact with air and has a concave shape on the image display surface side. The projection optical system according to any one of claims 1 to 4, wherein:

6. The optical system according to any one of claims 1 to 5, wherein an aperture stop is provided between the lens closest to the image display surface and the lens closest to the projection surface in the lens system.魏 optical system.

7. Of the positive lenses included in the lens system, the refractive index of the positive lens located closest to the image display surface with respect to the e-line of the lens material: n Pe force Condition:

(2) 1.4 5 <n P e <1.6 5 The optical system according to any one of claims 1 to 6, wherein the optical system satisfies the following.

8. The curved mirror closest to the projection surface in the imaging optical path is an axial surface with the optical axis formed by the largest number of lenses in the lens system as ¾ ^. 8. The optical system according to any one of items 7 to 7.

9. In the lens system, there is an aperture stop between the lens closest to the image display surface and the lens closest to the projection surface, and for each spherical negative lens located between this aperture stop and the curved mirror, the lens material Refractive index of ¾ ~ between e-line: n N e force Condition:

(3) 2. 0> n N e> 1. 6 5

The projection optical system according to any one of claims 1 to 8, which satisfies the following requirement.

10. The optical system according to any one of claims 1 to 9, wherein the number of curved mirrors is one.

1 1. Projector equipped with the projection optical system according to any one of claims 1 to 10

1 2. The apparatus according to any one of claims 1 to 10 is used as a reduction optical system, and the light receiving surface of the image sensor is arranged at a position to be an image display surface. Images to capture images