JP2001194584A - Projection lens and video projecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the deterioration of a projected image caused by image blurring and to obtain the high-quality projected image. SOLUTION: A 1st lens group G1 and a 2nd lens group G2 having positive refractive power as a whole are arranged in order from an image surface side. A 1st lens component L which has negative refractive power and whose convex surface faces to an image side is arranged nearest to the object side in the 1st lens group G1. A 2nd lens component L2 whose convex surface faces to the object side and at least one surface of which consists of a bonded surface is arranged nearest to the image surface side in the 2nd lens group G2, and a 3rd lens component L3 having positive refractive power is arranged nearest to the object side in the 2nd lens group G2. The 3rd lens component L3 is a lens component for correcting the image blurring and is constituted to move in directions X and Y orthogonal to an optical axis O.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection lens and an image projection apparatus for projecting an optically provided image on a screen or the like while correcting image shake.

[0002]

2. Description of the Related Art Conventionally, a projection lens has been used for an optical system of a projection apparatus for projecting an image recorded on a movie film onto a screen, for example. Also, the projection lens is
For example, it is also used in an optical system of a telecine device that shoots an image recorded on a movie film with a camera and converts the image into a video signal. Further, projection lenses are used in optical systems of various video projectors for projecting optically provided video, in addition to so-called film processing devices such as projection devices and telecine devices.

[0003]

By the way, conventionally,
In the image projection device, a phenomenon in which the position of the projected image is displaced (hereinafter, such a phenomenon is referred to as "image blur") has become a problem. For example, in a film processing apparatus, image blurring occurs when the running position of the film is not always set to a fixed position. In the film processing apparatus, there are a continuous feeding system and an intermittent feeding system as a system of a film traveling system, and the blur occurs in any of the systems. For example, in the continuous feed system,
There is a disadvantage that it is difficult to completely synchronize the scanning of the illumination light with the movement of the motion picture film, which causes image blurring. In the intermittent feeding method, pins called registration pins are inserted into feed holes called perforations provided at both ends in the width direction of the movie film to position the movie film. It is necessary to provide a gap between the registration pin and the perforation in order to avoid damage to the film, which causes displacement of the film position and image blurring.

When such image blur occurs, for example, in a projection apparatus, an image is magnified several hundred times by a projection lens and projected on a screen. Will deteriorate. In addition, there is a problem that the deterioration of the image quality due to the image blur causes a viewer to be tired.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to reduce the deterioration of a projected image due to image blur and to obtain a high-quality projected image and a video projection. It is to provide a device.

[0006]

A projection lens according to the present invention is a projection lens for projecting an optically provided image, and has a plurality of lens components and at least one of the plurality of lens components. The apparatus is configured to be movable in a direction orthogonal to the optical axis in accordance with the shake of the image so that the shake of the image to be projected is corrected.

Here, in the projection lens according to the present invention, for example, at least a first lens group having a positive refractive power and a second lens group having a positive refractive power are arranged in this order from the image plane side. The first lens group is arranged closest to the object side and includes a first lens component having a negative refractive power and a convex surface facing the image side, and the second lens group is most A second lens component, which is arranged on the image surface side and faces the object side and has at least one surface formed of a cemented surface, and a second lens component which is arranged closest to the object side and has a positive refractive power. And a third lens component, or the second lens component and the third lens component are desirably configured to be movable in a direction orthogonal to the optical axis.

An image projection apparatus according to the present invention is an image projection apparatus for projecting an optically provided image via a projection lens, wherein the projection lens has a plurality of lens components and a plurality of lens components. At least one is configured to be movable in a direction orthogonal to the optical axis according to the shake of the image so that the shake of the image to be projected is corrected.

In the projection lens and the image projection apparatus according to the present invention, at least one of the plurality of lens components moves in a direction perpendicular to the optical axis in accordance with the shake of the image to be projected, thereby correcting the image shake. Is done.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a diagram showing a main structure of a projection device as an image projection device according to an embodiment of the present invention.
The projection device 1 is for projecting an image recorded on a movie film 2, and as shown in FIG. 1, the movie film 2 to be projected is held at a predetermined position so as to be clamped. A gate section 21, an intermittent feeding section 22 for intermittently feeding the movie film 2, and a lamp house section 24 containing a light source 24A for emitting light L1 for projection toward the movie film 2 held by the gate section 21; Inside,
The camera includes a lens unit 27 on which a projection lens 28 for optically enlarging an image recorded on the movie film 2 is arranged, and a screen 29 on which the image enlarged by the projection lens 28 is projected. Although not shown, the projection device 1 further includes a supply reel for supplying the movie film 2, a take-up reel for winding the movie film 2 supplied from the supply reel, and a sound recorded on the movie film 2. And a sound reproducing unit for reproducing. The gate section 21 and the intermittent feed section 22 are arranged between the supply reel and the take-up reel.

The projection apparatus 1 further includes a motion picture film 2
A position detection unit 33 that outputs detection signals SX0 and SY0 corresponding to the amount of positional deviation in the width direction and the longitudinal direction, a main control unit 34 that controls each unit of the projection device 1, and an amount of positional deviation of the movie film 2. The image blur correction mechanism 41 for moving the lens component for image blur correction in the projection lens 28 in a direction orthogonal to the optical axis in response to the image blur correction control signals SX1 and SY1 from the main controller 34. And a drive control unit 42 for driving and controlling the correction mechanism unit 41.

Although not shown, the movie film 2 is provided with perforations called perforations for synchronizing running at predetermined intervals at both ends in the width direction. An image recording area for optically recording an image is provided between two rows of perforations provided at both ends in the width direction of the movie film 2. At least one end in the width direction of the movie film 2 is provided with a digital audio recording area in which digital audio is optically recorded and an analog audio recording area in which analog audio is optically recorded.

The lamp house 24 has, in addition to the light source 24A, a shutter 24B that opens and closes in conjunction with the intermittent feeding operation of the movie film 2, and a motor 24C that drives the shutter 24B.

The gate section 21 has a picture gate 21A and a pressure plate 21B, and is configured such that the movie film 2 is sandwiched between the picture gate 21A and the pressure plate 21B.
A steel band 31 is provided on a surface of the picture gate 21A facing the movie film 2. A guide shoe 32 having a curved surface is provided on the surface of the pressure plate 21B facing the movie film 2. The picture gate 21A and the pressure plate 21B are provided with a picture aperture (not shown) having a size corresponding to the video recording area of the movie film 2.

The intermittent feed portion 22 has an intermittent feed sprocket 22A and a sprocket shoe 22B, and is configured to sandwich the movie film 2 between the intermittent feed sprocket 22A and the sprocket shoe 22B. In the intermittent feed section 22, the intermittent feed sprocket 22A sequentially rotates by a predetermined angle at a predetermined timing based on the drive control of the servomotor 23, whereby each video recording area of the movie film 2 is transferred to the gate section 21. Momentarily (for example, at a rate of 24 times / second)
The movie film 2 is intermittently fed so as to stop sequentially.

When the motion picture film 2 stops at the gate, the position detection section 33 detects the amount of displacement in the width direction and the length direction of the motion picture film 2 at the stop position.
The detection signals SX0 and SY0 corresponding to the displacement are output to the main control unit 34. The position detection unit 33
For example, the position of the perforation provided in the movie film 2 in the width direction and the longitudinal direction is determined by the picture gate 2.
By comparing the position of a picture aperture (not shown) provided on the pressure plate 1B and the pressure plate 21B, the amount of positional deviation of the movie film 2 is detected. The main control unit 34 sends image drive correction control signals SX1 and SY1 for correcting image drive to the drive control unit 42 based on the position shift amount of the movie film 2 detected by the position detection unit 33. It has become. In addition,
The main control unit 34 has a memory for storing a relation table indicating the relation between the amount of position shake detected by the position detection unit 33 and the amount of movement of the lens component for image shake correction.

In the projection device 1 having such a configuration, the movie film 2 is continuously supplied from the supply reel (not shown) to the gate section 21 and the supplied movie film 2 is continuously supplied to the take-up reel (not shown). It is wound up. The intermittent feed sprocket 22A of the intermittent feed unit 22 sequentially rotates by a predetermined angle at a predetermined timing, whereby each image recording area of the movie film 2 continuously supplied from the supply reel is instantaneously transferred to the gate unit 21. The movie film 2 is intermittently fed so as to stop intermittently.

In the projection apparatus 1, the shutter 24B of the lamp house 24 is interlocked with the intermittent feeding operation of the movie film 2.
Are opened and closed, and when the video recording area of the movie film 2 stops at a predetermined position of the gate section 21, light from the lamp house 24 is projected onto the video recording area of the movie film 2. The projection light transmitted through the image recording area of the movie film 2 is enlarged and projected on a screen 29 by a projection lens 28 of a lens unit 27. The sound recorded on the movie film 2 is reproduced by a sound reproducing unit (not shown).

Further, in the projection apparatus 1, when the movie film 2 stops at the gate portion, the amount of displacement in the width direction and the longitudinal direction of the movie film 2 at the stop position is detected by the position detection unit 33, and Detection signals SX0 and SY0 corresponding to the amount of positional deviation are output to the main control unit 34. The main control unit 34 sends image shake correction control signals SX1 and SY1 for correcting image shake to the drive control unit 42 based on the amount of position shake detected by the position detection unit 33.
The drive control unit 42 drives the image blur correction mechanism unit 41 based on the image blur correction control signals SX1 and SY1, and
Is moved in the direction orthogonal to the optical axis. As described above, in the projection device 1, even if the motion of the movie film 2 stopped at the gate unit 21 is displaced, the lens component for correcting the image shake of the projection lens 28 is orthogonal to the optical axis in accordance with the displacement. , And the optical axis of the projection light is corrected. As a result, in the projection device 1, even if the movie film 2 is displaced, the image shake of the projected image on the screen 29 is corrected.

Next, the projection lens 28 according to the present embodiment
Will be described in detail.

FIG. 2 shows an example of the lens configuration of the projection lens 28. In FIG. 2, the cross-sectional structure of the projection lens device 28 in a plane including the optical axis O is shown. Reference numerals S1 to S6 and S8 to S12 in the drawing indicate surface numbers of the respective lens elements, and reference numeral S7 indicates an aperture stop. Reference numeral S13 indicates a film surface (object surface) of the movie film 2. Therefore, in the figure, the lens surface S1
The direction is the image surface side (projection side), and the film surface S13 direction is the object side. In the figure, a plurality of light beam groups passing through the projection lens 28 are shown together with the lens elements of the projection lens 28.

As shown in the figure, the projection lens 28
The whole is configured as a so-called Gaussian lens, and in order from the image plane side, at least a first lens group G1 having a positive refractive power and a second lens group G2 having a positive refractive power
Are arranged. Second lens group G2
Is disposed closer to the object side than the first lens group G1 via the aperture stop S7. Therefore, in the projection lens 28,
When an optical image is provided on the object side by irradiating the cinema film 2 with light, the image is incident from the object side in the order of the second lens group G2 and the first lens group G1, and the screen A projection image enlarged toward 29 (FIG. 1) is formed.

The first lens group G1 includes a positive meniscus lens E1 having a convex surface facing the image surface, a positive meniscus lens E2 having a convex surface facing the image surface, and a negative meniscus lens E2 having a convex surface facing the image surface. And a meniscus lens E3 (L1). In the first lens group G1, lenses E1, E2, and E3 are arranged in this order from the image plane side. As described above, the negative meniscus lens E3 as the first lens component L1 having the convex surface facing the image side is disposed closest to the object side of the first lens group G1.

The second lens group G2 includes a second lens component L2 having a convex surface facing the object side, at least one surface of which is a cemented surface, and a biconvex lens E6 having a positive refractive power.
(L3). The second lens component L2 has a negative refracting power as a whole, and in the example of the figure, has a cemented lens in which a biconcave lens E4 and a biconvex lens E5 are cemented at a surface S9. . Second lens group G
2, the lenses E4, E5, E
6 are arranged in this order. As described above, the second lens component L2 is disposed closest to the aperture stop S7 on the image plane side of the second lens group G2, and is closest to the object side.
A biconvex lens E6 as the third lens component L3 is arranged.

At least one of the lens components of the projection lens 28 is configured to be movable in a direction orthogonal to the optical axis O in accordance with the shake of the image so that the shake of the image to be projected is corrected. I have. In the present embodiment, the second
The third lens component L3 of the lens group G2 is a lens component for image blur correction, and is in the X direction orthogonal to the optical axis O and in the Y direction.
It is configured to be movable in the direction. Note that the moving direction of the lens component for image blur correction cannot always be completely orthogonal to the optical axis O due to mechanical accuracy. In the present embodiment, the moving directions of the lens components for image blur correction need only be substantially orthogonal as long as image blur can be corrected.

Here, in the projection lens 28, it is desirable that at least one lens surface of at least one of the first lens group G1 and the second lens group G2 is formed as an aspheric surface. In the present embodiment, for example, as shown in FIG. 3, the image-side surface S3 of the meniscus lens E2 in the first lens group G1 and the second object component of the second lens component L2 in the second lens group G2 The side surface S10 is formed of an aspheric surface. When at least one surface of the projection lens 28 is formed as an aspheric surface as described above,
Mainly, spherical aberration and coma can be effectively removed. In particular, if the surface close to the aperture stop S7 is formed of an aspherical surface, it is effective for removing spherical aberration, and since the lens surface forming the aspherical surface has a small diameter, highly accurate aspherical processing can be performed. Become.

In the projection lens 28, when the focal length of the second lens group G2 is f2 and the focal length of the entire lens system is f, it is desirable that the following conditional expression (1) is satisfied. .

0.5 <f2 / f <1.5 (1)

This conditional expression (1) satisfies the second lens group G2
An appropriate range is determined for the ratio of the focal length f2 of the lens system to the focal length f of the entire lens system. When the value goes below the lower limit of conditional expression (1), spherical aberration tends to be excessive on the negative side, which is disadvantageous in terms of performance. On the other hand, when the value exceeds the upper limit of the conditional expression (1), the spherical aberration tends to be excessive on the negative side, which is disadvantageous in terms of performance. When the value exceeds the upper limit value of the conditional expression (1), the Petzval sum tends to largely shift to the positive side, and the focus position on the film surface S13 tends to bend in the negative direction, which is not preferable.

In the projection lens 28, the focal length of the third lens component L3 is f4, and the magnitude of the maximum displacement of the third lens component L3 in the direction orthogonal to the optical axis O during image blur correction. Is ΔS, it is desirable to satisfy the following conditional expression (2).

ΔS / f4 <0.01 (2)

This conditional expression (2) defines an appropriate range for the ratio between the magnitude ΔS of the maximum displacement in the direction orthogonal to the optical axis O and the focal length f4 in the lens component for image blur correction. It is. If conditional expression (2) is not satisfied,
The value ΔS of the maximum displacement amount of the lens component for image blur correction at the time of image blur correction becomes too large, and the aberration fluctuation amount at the time of image blur correction becomes large, which is disadvantageous in performance.

Further, in the projection lens 28, the focal length of the whole lens system is f, the maximum object height (the size of the movie film 2) is Y _max, and the third lens which is a lens component for image blur correction is used. When the value of the Abbe number of the component L3 is νa, it is desirable that the following conditional expressions (3) and (4) are satisfied.

0.18 <Y _max /f<0.4 (3) 45 <νa (4)

Here, the conditional expression (3) satisfies the maximum object height Y
_An appropriate range is defined for the ratio of the focal length f of the entire lens system to _max . When the value exceeds the upper limit of conditional expression (3), the Petzval sum tends to be excessively large on the positive side, which is disadvantageous in performance. Conversely, when the value goes below the lower limit of conditional expression (3), the angle of view becomes too large, and off-axis aberrations and
In particular, field curvature and coma cannot be corrected completely, which is inconvenient in terms of performance. If the lower limit of conditional expression (3) is not reached, the back focus tends to be insufficient, which is inconvenient. Conditional expression (4) is an important condition for obtaining good chromatic aberration correction even when image blur correction is performed, that is, when a lens component for image blur correction is moved. If conditional expression (4) is not satisfied, the axial chromatic aberration of a short wavelength will be excessive on the negative side during image blur correction, making it difficult to obtain good imaging performance.

FIG. 3 shows the specification values of the projection lens 28 in the lens configuration shown in FIG. In the figure, f represents the focal length, and Bf represents the back focus. Fno represents an F number in a projection state from infinity. The surface number indicates the order of the lens surface from the image surface side opposite to the direction in which the light rays travel (projection direction).
, S1 to S13. The refractive index and Abbe number indicate values for the d-line (wavelength λ = 587.6 nm). The units of the values of the radius of curvature, the surface interval, the focal length f, and the back focus Bf are millimeters (mm).

The values of the aspherical coefficients A, B, C, D, and E shown in FIG. 3B are coefficients in a predetermined aspherical polynomial representing the aspherical shape. Here, the aspherical polynomial is obtained by taking the Z axis in the optical axis direction and the H axis in the direction orthogonal to the optical axis O, making the traveling direction of light negative, and R as the paraxial radius of curvature, and the following equation (A ).

Z = ((1 / R) H ² ) / [1+ {1- (H / R) ² } ^1/2 ] + AH ² + BH ⁴ + CH ⁶ + DH ⁸ + EH ¹⁰ (A)

In the equation (A), H represents a distance from the optical axis O, and Z represents a sag amount of the lens at a distance H from the optical axis O. Aspheric coefficient A,
In Equation (A), B, C, D, and E are, respectively, quadratic,
These are fourth, sixth, eighth and tenth order coefficients. In the aspherical polynomial of the formula (A), when the second-order aspherical coefficient A is zero, it indicates that the surface shape of the paraxial lens is spherical.

FIG. 9C shows the above-mentioned conditional expressions (1) to (5).
The value corresponding to (4) is shown. As shown in the figure, in the projection lens 28 according to the present embodiment, the value of the focal length f of the entire lens system is 100 mm,
Since the value of the focal length f2 of the lens group G2 is 82.5 mm, f2 / f = 0.825, which satisfies the conditional expression (1).

In the projection lens 28, the value ΔS of the maximum displacement in the direction orthogonal to the optical axis O of the third lens component L3 at the time of image blur correction is 0.2 mm. The value of the focal length f4 of the lens component L3 is 99.
Since it is 2 mm, ΔS / f4 = 0.0020, and
The conditional expression (2) is satisfied.

Further, in the projection lens 28, the value of the focal length f of the entire lens system is 100 mm, and the value of the maximum object height (the size of the movie film 2) Y _max is 27.2 m.
Since m, Y _max /f=0.272, which satisfies the conditional expression (3). Furthermore, the projection lens 2
In No. 8, since the value of the Abbe number νa of the third lens component L3 is 47.5, the above-mentioned conditional expression (4) is satisfied.

FIG. 4 shows an example of a table showing the relationship between the lens movement amount of the third lens component L3 in the projection lens 28 and the film movement amount (position shake amount) of the movie film 2. FIG. 5 is a graph showing the relationship between the lens movement amount and the film movement amount shown in FIG. In the present embodiment, when the motion of the movie film 2 is displaced, the third lens component L3, which is a lens component for image stabilization, is moved in the same direction as the moving direction of the movie film 2. It has become. Main control unit 3
4 (FIG. 1) stores the relationship table as shown in FIG. 4 in a memory (not shown) in advance. Main control unit 34
Obtains the amount of movement of the position detected by the position detection unit 33, calculates an appropriate value of the amount of movement of the lens from a relation table stored in advance, and calculates an appropriate amount of movement of the image in the same direction as the movement direction of the movie film 2. The image blur correction control signals SX1 and SY are sent to the drive control unit 42 to move the lens components.
Send 1

FIGS. 6 to 8 show various aberrations on the film surface S13 when light is back-projected from infinity to the projection lens 28 having the specification values shown in FIG. 3 (back-projection state). FIG. FIG. 6 shows the third lens component L
3 shows spherical aberration (FIG. 7A), astigmatism (FIG. 7B), and distortion (FIG. 7C) when the lens movement amount is zero. FIG. 7 shows the third lens component L
FIG. 8 shows lateral aberrations when the lens movement amount of the third lens component L3 is 0.2 mm as an example of lateral aberrations when image blur correction is performed. Shows the lateral aberration. In each of these aberration diagrams, the symbol Y represents the image height, and the symbol E represents the e-line (wavelength λ = 54).
6.1 nm), and the symbol F is F line (wavelength λ = 486.1n).
m), and the symbol C indicates a C line (wavelength λ = 656.3 nm). In the aberration diagram of FIG. 6B showing astigmatism, reference symbol S indicates a sagittal image plane, and reference symbol T indicates a meridional (tangential) image plane. The lateral aberrations shown in FIGS. 7 and 8 indicate aberrations in two directions X and Y (see FIG. 2) orthogonal to each other in the film plane for each image height.

As is clear from the aberration diagrams, the projection lens 28 can be moved not only when the amount of movement of the third lens component L3 is zero, but also when the third lens component L3 is moved for image blur correction. Also, it can be seen that various aberrations are satisfactorily corrected from the center to the periphery.

FIG. 9 is a diagram showing vignetting on the film surface S13 in the back projection state of the projection lens 28. In the figure, the horizontal axis indicates the height on the film surface S13, and the vertical axis indicates vignetting. In the figure, the vertical axis represents the state where vignetting is zero. As shown in the figure,
It can be seen that the projection lens 28 has no vignetting at all around the periphery. Therefore, the projection lens 28 according to the present embodiment has a high aperture efficiency and a bright lens performance from the center to the periphery.

In general, in the case of a projection optical system, the illuminance distribution on a screen onto which a projection image is projected is determined by the relationship between an illumination optical system such as a reflecting mirror and another lens system, and the projection lens alone. It is not determined by. However, vignetting of the projection lens has a considerable effect on the illuminance distribution on the screen, so the values of vignetting are shown here for reference.

As described above, according to the projection lens 28 and the projection device 1 according to the present embodiment, the motion of the movie film, that is, the motion of the motion picture film 2 is corrected so that the motion of the image to be projected is corrected. Since the lens component for image blur correction is moved in a direction orthogonal to the optical axis in accordance with the position shake of 2, the deterioration of the projected image due to the influence of the image shake is reduced, and a high-quality projected image is obtained. be able to.
As described above, according to the projection lens 28 and the projection device 1 according to the present embodiment, the influence of image blur can be reduced, and thus the viewer's fatigue due to image blur can be reduced.

The projection lens 28 according to the present embodiment
According to the above, the projection lens 28 is configured by arranging at least the first lens group G1 having a positive refractive power and the second lens group G2 having a positive refractive power in order from the image plane side,
The first lens group G1 is disposed closest to the object side, includes a first lens component L1 having a negative refractive power and a convex surface facing the image side, and the second lens group G2 is disposed closest to the image side. Surface side, with the convex side facing the object side, at least one
A second lens component L2 having two surfaces formed of a cemented surface,
Since the third lens component L3 having the positive refractive power and being disposed closest to the object side is provided, the image quality and aperture efficiency in the peripheral portion are improved, and a high-quality projected image is provided throughout. Can be obtained. Therefore, in the projection device 1 according to the present embodiment, a high-quality image can be projected over the entire screen. Further, according to the projection lens 28 of the present embodiment, since at least one surface is formed of an aspherical surface, spherical aberration and coma can be effectively removed.

[Modification] Next, a modification of the present invention will be described. In the following description, the same portions as the components in the above embodiment are denoted by the same reference numerals, and the description will be appropriately omitted. The overall configuration of a projection device as a video projection device according to this modification is the same as that of the projection device 1 shown in FIG. 1, but the configuration of a projection lens 28 applied to the lens unit 27 is different.

FIG. 10 shows a projection lens 2 according to this modification.
This figure shows the lens configuration of 8 ', and the figure shows the cross-sectional structure of the projection lens device 28' in a plane including the optical axis O. Also, reference numerals S1 to S6, S8 to S1 in the drawing
Reference numeral 4 denotes a surface number of each lens element, and reference numeral S7 denotes an aperture stop. Reference sign S15 indicates the film surface (object surface) of the movie film 2. Therefore, in the drawing, the direction of the lens surface S1 is the image side (projection side), and the direction of the film surface S15 is the object side. In the figure, a plurality of light beams passing through the projection lens 28 'are shown together with the lens elements of the projection lens 28'.

As shown in the figure, the projection lens 28 '
Are, in order from the image plane side, at least a first lens group G1 'having a positive refractive power and a second lens group G2' having a positive refractive power, similarly to the projection lens 28 shown in FIG. Are arranged and configured. The second lens group G2 '
It is located closer to the object side than the first lens group G1 'via the aperture stop S7. Therefore, in the projection lens 28 ',
When an optical image is provided by irradiating the cinema film 2 with light on the object side, the image is incident from the object side in the order of the second lens group G2 'and the first lens group G1'. Thus, a projection image enlarged toward the screen 29 (FIG. 1) is formed.

The first lens group G1 'includes a positive meniscus lens E1' having a convex surface facing the image surface, a positive meniscus lens E2 'having a convex surface facing the image surface, and a convex meniscus lens E2' having a convex surface facing the image surface. And a negative meniscus lens E3 '(L1'). In the first lens group G1 ', lenses E1', E2 ', E3' are arranged in this order from the image plane side. As described above, the negative meniscus lens E is located closest to the object side of the first lens group G1 ', like the first lens group G1 of the projection lens 28 shown in FIG.
3 'is arranged as a first lens component L1'.

The second lens unit G2 'has a second lens component L2' having a convex surface facing the object side, at least one surface of which is a cemented surface, and a biconvex lens E having a positive refractive power.
7 ′ (L3 ′). Second lens component L
Reference numeral 2 'includes a biconcave lens E4', a biconvex lens E5 ', and a meniscus lens E6', and the overall refractive power is negative. The biconcave lens E4 'and the biconvex lens E5' of the second lens component L2 'form a cemented lens cemented at the surface S9. The meniscus lens E6 'of the second lens component L2' has a negative meniscus configuration with the convex surface facing the film surface S15. In the second lens group G2 ', lenses E4', E5 ', E6', and E7 'are arranged in this order from the image plane side. Thus, the second lens group G
A second lens component L2 'is disposed closest to the aperture stop S7 on the image plane side of 2', and a biconvex lens E7 'as a third lens component L3' is disposed on the most object side. ing.

In the projection lens 28 ', the second lens component L2' and the third lens component L3 'of the second lens group G2' are lens components for image blur correction. Is the projection lens 2 shown in FIG.
Like FIG. 8, it is configured to be movable in the X direction and the Y direction orthogonal to the optical axis O. Note that the moving direction of the lens component for image blur correction cannot always be completely orthogonal to the optical axis O due to mechanical accuracy. In the present modification, the moving directions of the lens components for image blur correction need only be substantially orthogonal as long as the image blur can be corrected.

Here, in the projection lens 28 ', the first
It is preferable that at least one lens surface of at least one of the lens group G1 'and the second lens group G2' is formed of an aspheric surface. In this modification,
For example, as shown in FIG. 11, the image-side surface S3 of the meniscus lens E2 'in the first lens group G1' is formed of an aspheric surface. The operation and effect of configuring at least one surface of the projection lens 28 'with an aspherical surface are as follows.
This is the same as the projection lens 28 shown in FIG.

In the projection lens 28 ', FIG.
As in the case of the projection lens 28 shown in FIG.
When the focal length of 2 ′ is f2 and the focal length of the entire lens system is f, it is desirable to satisfy the following conditional expression (1). The function and effect of satisfying conditional expression (1) are the same as those of projection lens 28 shown in FIG.

0.5 <f2 / f <1.5 (1)

In the projection lens 28 ', FIG.
Similarly to the projection lens 28 shown in FIG.
The focal length of 3 'is f4, and the third
When the magnitude of the maximum displacement of the lens component L3 ′ in the direction perpendicular to the optical axis O is ΔS, it is desirable that the following conditional expression (2) is satisfied. The function and effect of satisfying conditional expression (2) are as follows.
Is the same as

ΔS / f4 <0.01 (2)

Further, in the projection lens 28 ', the focal length of the entire lens system is f, the maximum object height (the size of the movie film 2) is Y _max, and it is one of the lens components for image blur correction. When the value of the Abbe number of the third lens component L3 ′ is νa, it is desirable that the following conditional expressions (3) and (4) are satisfied. The function and effect of satisfying conditional expressions (3) and (4) are the same as those of the projection lens 28 shown in FIG.

0.18 <Y _max /f<0.4 (3) 45 <νa (4)

FIG. 11 shows the specification values of the projection lens 28 'in the lens configuration shown in FIG. The meanings of the respective symbols in the figure are the same as in FIG.

FIG. 9C shows values corresponding to the above-mentioned conditional expressions (1) to (4), similarly to FIG. As shown in the figure, in the projection lens 28 'according to this modification, the value of the focal length f of the entire lens system is 100 mm.
And the value of the focal length f2 of the second lens group G2 'is 7
Since it is 9.3 mm, f2 / f = 0.793, and
The condition (1) is satisfied.

In the projection lens 28 ′, the value ΔS of the maximum displacement of the third lens component L 3 ′ in the direction orthogonal to the optical axis O during image blur correction is 0.2 mm.
Since the value of the focal length f4 of the third lens component L3 ′ is 73.7 mm, ΔS / f4 = 0.0027, which satisfies the conditional expression (2).

Further, in the projection lens 28 ', the value of the focal length f of the entire lens system is 100 mm, and the value of the maximum object height (the size of the movie film 2) Y _max is 27.2.
mm, Y _max /f=0.272, which satisfies the conditional expression (3). Further, in the projection lens 28 ', since the value of the Abbe number νa of the third lens component L3' is 47.5, the above-mentioned conditional expression (4) is satisfied.
Are satisfied.

FIG. 12 shows the amount of lens movement of the image blur correcting lens components (the second lens component L2 'and the third lens component L3') in the projection lens 28 'and the amount of film movement of the movie film 2 (position). 3 shows an example of a table indicating a relationship between the table and the shake amount. FIG. 13 is a graph showing the relationship between the lens movement amount and the film movement amount shown in FIG. In the present embodiment, when the motion of the motion picture film 2 is displaced, the second lens component L2 ′ and the third lens component L2 ′, which are Is moved. Main control unit 34
In FIG. 1, the relation table as shown in FIG. 12 is stored in a memory (not shown) in advance. Main control unit 34
Obtains the amount of movement of the position detected by the position detection unit 33, calculates an appropriate value of the amount of movement of the lens from a relation table stored in advance, and calculates an appropriate amount of movement of the image in the same direction as the movement direction of the movie film 2. The image blur correction control signals SX1 and SY are sent to the drive control unit 42 to move the lens components.
Send 1

FIGS. 14 to 16 show a film surface S15 in a state where light is back-projected from infinity to the projection lens 28 'having the specification values shown in FIG. 11 (back-projection state).
It is a figure showing the above-mentioned various aberrations. FIG. 14 shows the spherical aberration (FIG. 14A) and the astigmatism (FIG. 14B) when the lens movement amount of the second lens component L2 ′ and the third lens component L3 ′ is zero. And distortion (FIG. 2C). FIG. 15 shows the second lens component L2 ′ and the third lens component L2 ′.
FIG. 16 shows lateral aberrations when the lens movement amount of the lens component L3 ′ is zero, and FIG. 16 shows the second lens component L2 ′ and the third lens component as an example of lateral aberration when image blur correction is performed. The lateral aberration when the lens movement amount of L3 'is 0.2 mm is shown. In each of these aberration diagrams,
The meaning of each code is the same as in FIGS. 6 to 8 described above.

As is apparent from these aberration diagrams, the projection lens 28 'is not limited to the case where the movement amount of the lens component for image blur correction is zero, as well as the image blur, similarly to the projection lens 28 shown in FIG. It can be seen that even when the lens component for correction is moved, various aberrations are satisfactorily corrected from the center to the periphery.

FIG. 17 is a diagram showing vignetting on the film surface S15 in the back projection state of the projection lens 28 '.
In the figure, the horizontal axis indicates the height on the film surface S15, and the vertical axis indicates vignetting. In the figure, the vertical axis represents the state where vignetting is zero. As shown in the figure, it can be seen that the projection lens 28 'has no vignetting over the periphery. Therefore, the projection lens 28 'according to the present modification has a high aperture efficiency and a bright lens performance from the center to the periphery, similarly to the projection lens 28 shown in FIG.

As described above, according to the projection lens 28 'of the present modification, similarly to the projection lens 28 shown in FIG. 2, the deterioration of the projected image due to the influence of image blur is reduced, and A projection image can be obtained.

The present invention is not limited to the above-described embodiment, and various modifications can be made. For example, the projection lens of the present invention can be used not only for a projection device, but also for other film processing devices such as a telecine device that captures an image recorded on a movie film with a camera and converts the image into a video signal. It is possible. Further, the projection lens of the present invention is not limited to an apparatus for projecting an image recorded on a cinema film, but may be widely applied to other projection apparatuses for projecting images provided optically from other than a cinema film. Is possible.

[0074]

As described above, claims 1 to 6
According to the projection lens according to any one of the above and the image projection device according to the seventh aspect, the image blur is corrected by correcting at least one of the plurality of lens components so that the image to be projected is corrected. , So that it is possible to move in the direction orthogonal to the optical axis, so that the deterioration of the projected image due to image blur can be reduced, and the effect that a high-quality projected image can be obtained without being affected by image blur can be obtained. Play.

In particular, according to the projection lens of the sixth aspect, in the projection lens of the second aspect, at least one lens surface of at least one of the first lens group and the second lens group is an aspheric surface. With this configuration, it is possible to more effectively remove spherical aberration and coma, and it is possible to obtain a higher-quality projected image.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a main configuration of a projection device as a video projection device according to an embodiment of the present invention.

FIG. 2 is a sectional view showing a configuration of a projection lens according to one embodiment of the present invention.

FIG. 3 is an explanatory diagram showing optical specification values of the projection lens shown in FIG.

FIG. 4 is an explanatory diagram showing an example of a table showing a relationship between a movement amount of a lens and a movement amount of a film in the projection lens shown in FIG.

FIG. 5 is an explanatory diagram showing the relationship between the amount of movement of the lens and the amount of movement of the film shown in FIG. 4 in a graph.

6 is an aberration diagram showing a spherical aberration, an astigmatism, and a distortion in a back projection state of the projection lens shown in FIG. 2;

FIG. 7 is an aberration diagram showing a lateral aberration in the back projection state of the projection lens shown in FIG. 2;

8 is an aberration diagram showing a lateral aberration at the time of image blur correction in the projection lens shown in FIG. 2;

FIG. 9 is an explanatory diagram showing vignetting in the back projection state of the projection lens shown in FIG. 2;

FIG. 10 is a cross-sectional view illustrating a configuration of a projection lens according to a modified example of the invention.

11 is an explanatory diagram showing optical specification values of the projection lens shown in FIG.

12 is an explanatory diagram showing an example of a table showing a relationship between a movement amount of a lens and a movement amount of a film in the projection lens shown in FIG.

FIG. 13 is an explanatory diagram showing the relationship between the amount of movement of the lens and the amount of movement of the film shown in FIG. 12 in a graph.

14 is an aberration diagram showing a spherical aberration, an astigmatism, and a distortion in a back projection state of the projection lens shown in FIG.

15 is an aberration diagram showing a lateral aberration in a back projection state of the projection lens shown in FIG.

16 is an aberration diagram showing a lateral aberration at the time of image blur correction in the projection lens shown in FIG.

FIG. 17 is an explanatory diagram showing vignetting in a back projection state of the projection lens shown in FIG. 10;

[Explanation of symbols]

G1, G1 ': first lens group, G2, G2': second lens group, L1, L1 ': first lens component, L2, L
2 ': second lens component, L3, L3': third lens component, 1: projection device, 2: movie film, 27: lens unit, 28: projection lens, 29: screen, 33: position detection unit, 34: Main control unit, 41: Image blur correction mechanism unit, 4
2. Drive control unit.

Claims (7)

[Claims] 1. A projection lens for projecting an optically provided image, comprising a plurality of lens components, wherein at least one of the plurality of lens components corrects a shake of an image to be projected. A projection lens that is configured to be movable in a direction orthogonal to the optical axis in accordance with a shake of an image. 2. The projection lens includes, in order from an image plane side, at least a first lens group having a positive refractive power and a second lens group having a positive refractive power are arranged. The first lens group includes a first lens component which is arranged closest to the object side and has a negative refractive power and has a convex surface facing the image side, and the second lens group is arranged closest to the image side. And with the convex surface facing the object side,
A second lens component having at least one surface formed of a cemented surface, and a third lens component disposed closest to the object and having a positive refractive power, wherein the third lens component; or The projection lens according to claim 1, wherein the second lens component and the third lens component are configured to be movable in a direction orthogonal to an optical axis. 3. When the focal length of the second lens group is f2 and the focal length of the entire lens system is f, the following expression is obtained: 0.5 <f2 / f <1.5 (1) The projection lens according to claim 2, wherein conditional expression (1) is satisfied. 4. The focal length of the third lens component is set to f4.
When the magnitude of the maximum displacement of the third lens component in the direction orthogonal to the optical axis at the time of image blur correction is ΔS, a conditional expression represented by ΔS / f4 <0.01 (2) 3. The projection lens according to claim 2, wherein (2) is satisfied. 5. When the focal length of the entire lens system is f, the maximum object height of the optically provided image is Y _max, and the value of the Abbe number of the third lens component is νa, .18 <Y _max /f<0.4 (3) 45 <νa (4) Satisfies conditional expressions (3) and (4). . 6. The projection lens according to claim 2, wherein at least one of the first lens group and the second lens group has at least one lens surface formed of an aspherical surface. 7. An image projection apparatus for projecting an optically provided image via a projection lens, wherein the projection lens has a plurality of lens components, and at least one of the plurality of lens components is: An image projection apparatus characterized in that it is configured to be movable in a direction orthogonal to the optical axis in accordance with the shake of the image so that the shake of the image to be projected is corrected.