JP2018169609A - Lens system, and image projection device and imaging device having lens system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lens system having a small lens diameter in which various aberrations are suppressed, and an image projection device and an image pickup device having the same. SOLUTION: Each of an enlarged conjugate point on an enlarged side and a reduced conjugate point on a reduced side and an intermediate imaging position inside a lens system are coupled to form an image, and an optical system on the enlarged side from the intermediate imaging position is enlarged. Optical system, the optical system on the reduction side from the intermediate image formation position is the relay optical system, and the lens system satisfying the conditions (1) and (2): 0.08 ≦ fp / fr ≦ 0.8 ... 1), {Ymax-ft ・ tan (ωmax)} / {ft ・ tan (ωmax)} ≦ -0.3 ... (2) Here, fr: Relay optics on the reduction side of the intermediate image formation position. System composite focal length, fp: Composite focal length of the magnified optical system on the magnified side of the intermediate image formation position, Ymax: Radius of effective image circle diameter, ωmax: Maximum half angle, ft: Focus of the entire lens system The distance. [Selection diagram] Fig. 1

Description

  The present disclosure relates to a lens system that forms an image by a lens system having a plurality of lens elements, and an image projection apparatus and an imaging apparatus having the lens system.

  Patent Document 1 includes a projection optical system, a relay optical system, and a display element that are arranged in order from the screen side along the optical axis. The projection optical system screens an image primarily formed by the relay optical system. An enlarged projection optical system including a negative group having a negative optical power and a positive group having a positive optical power, which are arranged in order from the screen side, is disclosed. As a result, an enlargement projection optical system that can ensure a very long back focus and has small chromatic aberration despite the short focal length is realized.

International Publication No. 2009/107553

  The present disclosure provides a lens system having a small lens diameter while suppressing various aberrations, and an image projection apparatus and an imaging apparatus having the lens system.

  A lens system in the present disclosure is a lens system that forms an image in a conjugate manner with each of an enlargement conjugate point on the enlargement side and a reduction conjugate point on the reduction side and an intermediate image formation position inside the lens system, and includes a plurality of lens elements. A positive power magnifying optical system located on the magnification side from the intermediate imaging position, and a positive power relay optical system having a plurality of lens elements and located on the reduction side from the intermediate imaging position, And satisfy the following conditions (1) and (2).

0.08 ≦ fp / fr ≦ 0.8 (1)
{Ymax−ft · tan (ωmax)} / {ft · tan (ωmax)} ≦ −0.3
... (2)
here,
fr: Composite focal length of relay optical system on the reduction side with respect to the intermediate imaging position fp: Composite focal length of enlargement optical system on the enlargement side with respect to the intermediate imaging position Ymax: Radius of effective image circle diameter ωmax: Half maximum Angle of view ft: focal length of the entire lens system.

  An image projection apparatus according to the present disclosure includes the lens system and an image forming element that generates an image to be projected onto a screen.

  An imaging apparatus according to the present disclosure includes the lens system and an imaging element that receives an optical image formed by the lens system and converts the optical image into an electrical image signal.

  According to the present disclosure, it is possible to realize a lens system having a small lens diameter while suppressing various aberrations.

Lens arrangement diagram showing in-focus state at a projection distance of 4000 mm of the lens system of Example 1 Lens arrangement showing the optical path of the lens system of Example 1 Longitudinal aberration diagram in the lens system of Example 1 Lens arrangement diagram showing in-focus state at a projection distance of 4000 mm of the lens system of Example 2 Lens arrangement showing the optical path of the lens system of Example 2 Longitudinal aberration diagram in the lens system of Example 2 Lens arrangement diagram showing in-focus state at a projection distance of 4000 mm of the lens system of Example 3 Lens arrangement showing the optical path of the lens system of Example 3 Longitudinal aberration diagram in the lens system of Example 3 Lens arrangement diagram showing in-focus state at a projection distance of 4000 mm of the lens system of Example 4 Lens arrangement showing the optical path of the lens system of Example 4 Longitudinal aberration diagram in the lens system of Example 4 Lens arrangement diagram showing in-focus state at a projection distance of 4000 mm of the lens system of Example 5 Lens arrangement showing the optical path of the lens system of Example 5 Longitudinal aberration diagram of the lens system of Example 5 Lens arrangement diagram showing in-focus state at a projection distance of 4000 mm of the lens system of Example 6 Lens arrangement showing the optical path of the lens system of Example 6 Longitudinal aberration diagram in the lens system of Example 6 Lens arrangement diagram showing in-focus state at a projection distance of 4000 mm of the lens system of Example 7 Lens arrangement showing the optical path of the lens system of Example 7 Longitudinal aberration diagram in the lens system of Example 7 Lens arrangement diagram showing the infinitely focused state of the lens system of Example 8 Lens arrangement showing the optical path of the lens system of Example 8 Longitudinal aberration diagram in the lens system of Example 8 Lens arrangement diagram showing the infinitely focused state of the lens system of Example 9 Lens arrangement showing the optical path of the lens system of Example 9 Longitudinal aberration diagram in the lens system of Example 9 Lens arrangement diagram showing the infinite focus state of the lens system of Example 10 Lens arrangement showing the optical path of the lens system of Example 10 Longitudinal aberration diagram in the lens system of Example 10 Lens arrangement diagram showing the infinitely focused state of the lens system of Example 11 Lens arrangement showing the optical path of the lens system of Example 11 Longitudinal aberration diagram in the lens system of Example 11

  Hereinafter, embodiments will be described in detail with reference to the drawings as appropriate. However, more detailed description than necessary may be omitted. For example, detailed descriptions of already well-known matters and repeated descriptions for substantially the same configuration may be omitted. This is to avoid the following description from becoming unnecessarily redundant and to facilitate understanding by those skilled in the art.

  The accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.

  1, 4, 7, 10, 13, 16, 19, 22, 25, 28, and 31 are lens arrangement diagrams of lens systems according to Examples 1 to 11, respectively. During focusing, the entire lens system moves in the optical axis direction. 1, 4, 7, 10, 13, 16, and 19, the arrow below the lens group symbol indicates a field curvature correcting lens group that moves along the optical axis when adjusting the field curvature amount. It moves to the enlargement side or the reduction side depending on the object distance and the radius of curvature of the screen surface.

  In each drawing, the enlargement-side image formation position is located on the left side, and the reduction-side image formation position is located on the right side. In each figure, the straight line described on the rightmost side (reduction side) represents the position of the original image S, and the optical element P is located on the left side (enlargement side) of the original image S. The optical element P represents an optical element such as a color separation / color combining prism, an optical filter, a parallel plate glass, a quartz low-pass filter, an infrared cut filter, or the like. When a lens element having a negative power and a lens element having a positive power are cemented, the positive power and the negative power are determined based on the total power of the cemented lens.

  2, 5, 8, 11, 14, 17, 20, 23, 26, 29, and 32 are optical sectional views showing optical paths of the lens systems according to Examples 1 to 11, respectively. With the intermediate image formation position MI as a boundary, the enlargement side is the enlargement optical system Op, and the reduction side is the relay optical system Ol. If the intermediate image formation position MI is inside the lens element, the relay optical system Ol is included including the lens element at the intermediate image formation position MI. The lens system according to the present disclosure conjugates each of the enlargement-side enlargement conjugate point (projected image) and the reduction-side reduction conjugate point (original image S) and the intermediate image formation position MI inside the lens system.

  The magnifying optical system Op includes a lens unit located on the magnifying side from a lens element having positive power on the most magnifying side as a front group Opf of the magnifying optical system, and includes a lens element having positive power located on the most magnifying side. The lens group on the side is provided as a rear group Opr of the magnifying optical system. When the cemented lens is located at the boundary between the front group Opf and the rear group Opr, the cemented lens is the rear group Opr when the total power is positive, and the cemented lens is the front group Opf when the total power is negative.

  3, 6, 9, 12, 15, 18, and 21 are longitudinal aberration diagrams of the lens systems according to Examples 1 to 7, respectively. (A), (b), and (c) in each figure are longitudinal aberration diagrams when the object distance of the lens system of the present disclosure is 4000 mm, 2000 mm, and 7000 mm, respectively.

  24, 27, 30 and 33 are longitudinal aberration diagrams of the lens systems according to Examples 8 to 11 in the infinitely focused state, respectively.

  Each longitudinal aberration diagram shows spherical aberration (SA (mm)), astigmatism (AST (mm)), and distortion (DIS) in order from the left side. In the spherical aberration diagram, the vertical axis represents the F number (indicated by F in the figure), the solid line is the d line (d-line), the short broken line is the F line (F-line), and the long broken line is the C line (C- line). In the astigmatism diagram, the vertical axis represents the image height, the solid line is the characteristic of the sagittal plane (indicated by s in the figure), and the broken line is the characteristic of the meridional plane (indicated by m in the figure). In the distortion diagram, the vertical axis represents the image height. Distortion aberration represents distortion aberration with respect to equidistant projection.

  Further, the lens system of the following embodiment is a projector that projects image light of an original image S obtained by spatially modulating incident light by an image forming element such as liquid crystal or DMD (Digital Micro-Mirror Device) based on an image signal onto a screen. A case of being used in (an example of an image projection apparatus) will be described. In the lens system of the present disclosure, a screen (not shown) is arranged on the extension line on the enlargement side, and the original image S such as a liquid crystal panel arranged on the reduction side is enlarged and projected onto the screen.

(Embodiments 1 and 2)
The configuration of the lens system according to Embodiments 1 and 2 will be described with reference to FIGS. The lens systems according to Embodiments 1 and 2 include a magnifying optical system Op and a relay optical system Ol.

  The magnifying optical system Op includes first to eleventh lens elements L11. The magnifying optical system Op includes a front group Opf and a rear group Opr. The front group Opf of the magnifying optical system Op includes a negative meniscus first lens element L1 having a convex surface on the magnifying side and a negative meniscus second lens having a convex surface on the magnifying side in order from the magnifying side to the reducing side. The lens element L2. The rear group Opr of the magnifying optical system Op includes, in order from the magnification side to the reduction side, a positive meniscus third lens element L3 with a convex surface facing the reduction side, and a fourth lens with a positive meniscus shape with the convex surface facing the object side. Lens element L4, biconcave fifth lens element L5, biconvex sixth lens element L6, biconvex seventh lens element L7, biconcave eighth lens element L8, reduction A positive meniscus ninth lens element L9 having a convex surface facing the side, a biconvex tenth lens element L10, and a positive meniscus eleventh lens element L11 having a convex surface facing the enlargement side. The seventh lens element L7 and the eighth lens element L8 are a field curvature correction lens group that moves along the optical axis when the field curvature amount is adjusted.

  The relay optical system Ol includes, in order from the enlargement side to the reduction side, a twelfth lens element L12 having a positive power, a biconcave thirteenth lens element L13, and a positive meniscus-shaped first lens with a convex surface facing the reduction side. A 14th lens element L14, a biconvex 15th lens element L15, a biconcave 16th lens element L16, a negative meniscus 17th lens element L17 with a convex surface facing the enlargement side, and a biconvex shape An eighteenth lens element L18, a negative meniscus nineteenth lens element L19 with a convex surface facing the reduction side, a biconvex twentieth lens element L20, and a negative meniscus twenty-first lens with a convex surface facing the reduction side It consists of an element L21 and a biconvex 22nd lens element L22. There is an intermediate imaging position MI between the eleventh lens element L11 and the twelfth lens element L12. A stop A is disposed between the sixteenth lens element L16 and the seventeenth lens element L17.

(Embodiments 3 to 4)
The configuration of the lens system according to Embodiments 3 and 4 will be described with reference to FIGS. The lens systems according to Embodiments 3 and 4 include a magnifying optical system Op and a relay optical system Ol.

  The magnifying optical system Op includes first to twelfth lens elements L1 to L12. The magnifying optical system Op includes a front group Opf and a rear group Opr. The front group Opf of the magnifying optical system Op includes a negative meniscus first lens element L1 having a convex surface on the magnifying side and a negative meniscus second lens having a convex surface on the magnifying side in order from the magnifying side to the reducing side. It consists of a lens element L2 and a biconcave third lens element. The rear group Opr of the magnifying optical system Op includes, in order from the magnification side to the reduction side, a biconvex fourth lens element L4, a positive meniscus fifth lens element L5 with a convex surface facing the reduction side, and a biconcave A sixth lens element L6 having a shape, a seventh lens element L7 having a biconvex shape, an eighth lens element L8 having a biconvex shape, a ninth lens element L9 having a biconcave shape, and a positive surface having a convex surface directed toward the reduction side. It comprises a meniscus tenth lens element L10, a biconvex eleventh lens element L11, and a positive meniscus twelfth lens element L12 with the convex surface facing the enlargement side.

  In the lens system according to Embodiment 3, the field curvature correcting lens group that moves along the optical axis when adjusting the field curvature amount is, as shown in FIG. 7, the ninth lens element L9 and the tenth lens. In the lens system according to Embodiment 4, the element L10 and the eleventh lens element L11 are the eighth lens element L8 and the ninth lens element L9 as shown in FIG.

  The relay optical system Ol includes, in order from the enlargement side to the reduction side, a positive meniscus thirteenth lens element L13 having a convex surface facing the reduction side, a biconcave fourteenth lens element L14, and a convex surface facing the reduction side. A positive meniscus fifteenth lens element L15, a negative meniscus sixteenth lens element L16 with a convex surface facing the enlargement side, a biconvex seventeenth lens element L17, and a negative meniscus with a convex surface facing the magnification side 18th lens element L18 having a shape, 19th lens element L19 having a biconvex shape, 20th lens element L20 having a biconcave shape, 21st lens element L21 having a biconvex shape, and negative with a convex surface facing the reduction side It comprises a meniscus 22nd lens element L22 and a biconvex 23rd lens element L23. There is an intermediate imaging position MI between the twelfth lens element L12 and the thirteenth lens element L13. A diaphragm A is disposed between the seventeenth lens element L17 and the eighteenth lens element L18.

(Embodiments 5 to 7)
The configuration of the lens system according to Embodiments 5, 6 and 7 will be described with reference to FIGS. 13, 14, 16, 17, 19 and 20. The lens systems according to Embodiments 5, 6, and 7 include the magnifying optical system Op and the relay optical system Ol.

  The magnifying optical system Op includes first to twelfth lens elements L1 to L12. The magnifying optical system Op includes a front group Opf and a rear group Opr. The front group Opf of the magnifying optical system Op includes a negative meniscus first lens element L1 having a convex surface on the magnifying side and a negative meniscus second lens having a convex surface on the magnifying side in order from the magnifying side to the reducing side. It comprises a lens element L2 and a negative meniscus third lens element with a convex surface facing the enlargement side. The rear group Opr of the magnifying optical system Op includes, in order from the magnification side to the reduction side, a biconvex fourth lens element L4, a positive meniscus fifth lens element L5 with a convex surface facing the reduction side, and a biconcave A sixth lens element L6 having a shape, a seventh lens element L7 having a biconvex shape, an eighth lens element L8 having a biconvex shape, a ninth lens element L9 having a biconcave shape, and a positive surface having a convex surface directed toward the reduction side. It comprises a meniscus tenth lens element L10, a biconvex eleventh lens element L11, and a positive meniscus twelfth lens element L12 with the convex surface facing the enlargement side. The eighth lens element L8 and the ninth lens element L9 are a field curvature correcting lens group that moves along the optical axis when the field curvature amount is adjusted.

  The relay optical system Ol includes, in order from the enlargement side to the reduction side, a positive meniscus thirteenth lens element L13 having a convex surface facing the reduction side, a biconcave fourteenth lens element L14, and a convex surface facing the reduction side. The positive meniscus fifteenth lens element L15, the biconvex sixteenth lens element L16, the biconcave seventeenth lens element L17, and the negative meniscus eighteenth lens element L18 with the convex surface facing the enlargement side. A biconvex 19th lens element L19, a biconcave 20th lens element L20, a biconvex 21st lens element L21, and a negative meniscus 22nd lens element with a convex surface facing the reduction side L22 and a biconvex 23rd lens element L23. There is an intermediate imaging position MI between the twelfth lens element L12 and the thirteenth lens element L13. A diaphragm A is disposed between the seventeenth lens element L17 and the eighteenth lens element L18.

(Embodiments 8 to 9)
The configuration of the lens system according to Embodiments 8 and 9 will be described with reference to FIGS. The lens systems according to Embodiments 8 and 9 include a magnifying optical system Op and a relay optical system Ol.

  The magnifying optical system Op includes first to tenth lens elements L10. The magnifying optical system Op includes a front group Opf and a rear group Opr. The front group Opf of the magnifying optical system Op includes a negative meniscus first lens element L1 having a convex surface on the magnifying side and a negative meniscus second lens having a convex surface on the magnifying side in order from the magnifying side to the reducing side. The lens element L2. The rear group Opr of the magnifying optical system Op includes, in order from the magnification side to the reduction side, a positive meniscus third lens element L3 having a convex surface on the reduction side, and a negative meniscus fourth lens having a convex surface on the reduction side. A lens element L4, a positive meniscus fifth lens element L5 with a convex surface facing the reduction side, a positive meniscus sixth lens element L6 with a convex surface facing the reduction side, and a positive meniscus with a convex surface facing the reduction side A seventh lens element L7 having a shape, an eighth lens element L8 having a negative meniscus shape with a convex surface facing the reduction side, a ninth lens element L9 having a biconvex shape, and a tenth lens element L10 having a biconvex shape. . The third lens element L3 and the fourth lens element L4 are cemented and have a total positive power.

  The relay optical system Ol includes, in order from the enlargement side to the reduction side, an eleventh lens element L11 having negative power, a negative meniscus twelfth lens element L12 having a convex surface facing the reduction side, and a biconcave shape. A thirteenth lens element L13, a positive meniscus fourteenth lens element L14 with a convex surface facing the reduction side, a biconvex fifteenth lens element L15, and a positive meniscus sixteenth lens with the convex surface facing the magnification side Element L16, biconcave seventeenth lens element L17, positive meniscus eighteenth lens element L18 with a convex surface facing the enlargement side, biconvex nineteenth lens element L19, and convex surface facing the magnification side The negative meniscus twentieth lens element L20, the biconvex twenty-first lens element L21, the biconcave twenty-second lens element L22, and the negative meniscus shape with the convex surface facing the enlargement side 23 lens elements L23, and the 24 lens element L24 having a biconvex shape, consisting of 25 lens elements L25 of a positive meniscus shape with a convex surface on the enlargement side. The seventeenth lens element L17 and the eighteenth lens element L18, the twenty-first lens element L21 and the twenty-second lens element L22, and the twenty-third lens element L23 and the twenty-fourth lens element L24 are cemented. In addition, an intermediate imaging position MI is in the eleventh lens element L11. A diaphragm A is disposed between the 22nd lens element L22 and the 23rd lens element L23.

(Embodiments 10 to 11)
The configuration of the lens system according to Embodiments 10 and 11 will be described with reference to FIGS. 28, 29, 31 and 32. FIG. The lens systems according to the tenth and eleventh embodiments include a magnifying optical system Op and a relay optical system Ol.

  The magnifying optical system Op is composed of the first lens element L1 to the eighth lens element L8. The magnifying optical system Op includes a front group Opf and a rear group Opr. The front group Opf of the magnifying optical system Op includes a negative meniscus first lens element L1 having a convex surface on the magnifying side and a negative meniscus second lens having a convex surface on the magnifying side in order from the magnifying side to the reducing side. The lens element L2. The rear group Opr of the magnifying optical system Op includes, in order from the magnification side to the reduction side, a biconvex third lens element L3, a negative meniscus fourth lens element L4 with a convex surface facing the reduction side, and a reduction side A positive meniscus fifth lens element L5 with a convex surface facing the convex side, a positive meniscus sixth lens element L6 with a convex surface facing the reduction side, and a negative meniscus seventh lens element L7 with the convex surface facing the reduction side And a biconvex eighth lens element L8. The third lens element L3 and the fourth lens element L4 are cemented and have a total positive power.

  The relay optical system Ol includes, in order from the enlargement side to the reduction side, a biconvex ninth lens element L9, a biconcave tenth lens element L10, a biconvex eleventh lens element L11, and an enlargement side. A positive meniscus twelfth lens element L12 with a convex surface facing the lens, a biconcave thirteenth lens element L13, a biconvex fourteenth lens element L14, and a negative meniscus lens with a concave surface facing the reduction side. 15 lens elements L15, negative meniscus sixteenth lens element L16 with a convex surface facing the enlargement side, biconvex seventeenth lens element L17, and positive meniscus eighteenth lens element with a convex surface facing the magnification side L18. The tenth lens element L10 and the eleventh lens element L11, the fourteenth lens element L14 and the fifteenth lens element L15, and the sixteenth lens element L16 and the seventeenth lens element L17 are cemented. Further, there is an intermediate imaging position MI between the eighth lens element L8 and the ninth lens element L9. A diaphragm A is disposed between the fifteenth lens element L15 and the sixteenth lens element L16.

  In the lens systems according to Embodiments 1 to 11, each of the enlargement-side enlargement conjugate point and the reduction-side reduction conjugate point and the intermediate image formation position inside the lens system are conjugately formed. In addition, the lens systems according to Embodiments 1 to 11 include a magnifying optical system composed of lens elements located on the magnification side from the intermediate image formation position, and a relay composed of lens elements located on the reduction side from the intermediate image formation position. And an optical system. When the intermediate image formation position is inside the lens element, the lens group on the enlargement side of the lens element is an enlargement optical system, and the lens group on the reduction side from the lens element at the intermediate image formation position is a relay optical system. It is. By forming an intermediate image of the original image by the relay optical system, it is easy to correct various aberrations, and in particular, it is easy to correct chromatic aberration of magnification.

  The lens systems according to Embodiments 1 to 11 include a front group Opf composed of lens elements on the enlargement side with respect to the positive power lens element arranged on the most enlargement side of the enlargement optical system Op, and the enlargement optical system Op. And a rear group Opr composed of a positive power lens element arranged on the most enlargement side to a reduction side lens element, and a magnifying optical system Op. As a result, the light incident on the enlargement side lens can be incident on the incident surface and the exit surface without being obliquely incident, thereby reducing the loss of light quantity due to reflection and suppressing aberrations of field curvature. it can.

  The lens systems according to Embodiments 1 to 11 include, in order from the enlargement side to the reduction side in the enlargement optical system Op, the negative meniscus first lens element L1 having a convex shape on the enlargement side, and the negative lens having a convex shape on the enlargement side. A front group Opf having a meniscus second lens element L2 is provided. As a result, a light beam incident on the lens on the enlargement side with a wide angle of view like a so-called fisheye lens can be incident on the incident surface and the exit surface without being obliquely incident, reducing the loss of light amount due to reflection, Aberration of field curvature can be reduced.

  The lens systems according to Embodiments 1 to 11 include, in the magnifying optical system Op, a rear group having a field curvature correcting lens group that moves in the optical axis direction when adjusting the amount of field curvature. As a result, it is possible to set an optimum amount of field curvature according to the object distance and the radius of curvature of the screen surface to be seen.

  The following description is given for conditions preferred to be satisfied by a lens system such as the lens systems according to Embodiments 1 to 11. A plurality of preferable conditions are defined for the lens system according to each embodiment, but a lens system configuration that satisfies all of the plurality of conditions is most desirable. However, by satisfying individual conditions, it is also possible to obtain lens systems that exhibit corresponding effects.

  The lens systems according to Embodiments 1 to 11 are lens systems that conjugately form each of an enlargement-side enlargement conjugate point and a reduction-side reduction conjugate point and an intermediate imaging position inside the lens element, A positive power magnifying optical system having a plurality of lens elements on the enlargement side from the intermediate imaging position, and a positive power relay optical system having a plurality of lens elements on the reduction side from the intermediate imaging position (Hereinafter, this lens configuration is referred to as a basic configuration of the embodiment). It is preferable that the lens system satisfies the following conditions (1) and (2).

0.08 ≦ fp / fr ≦ 0.8 (1)
{Ymax−ft · tan (ωmax)} / {ft · tan (ωmax)} ≦ −0.3
... (2)
here,
fr: Composite focal length of relay optical system on the reduction side with respect to the intermediate imaging position fp: Composite focal length of enlargement optical system on the enlargement side with respect to the intermediate imaging position Ymax: Radius of effective image circle diameter ωmax: Half maximum Angle of view ft: focal length of the entire lens system.

  Condition (1) is a conditional expression for defining the relationship between the combined focal length of the magnifying optical system and the relay optical system. By satisfying this condition, a lens system having a wide angle and a small lens diameter can be realized. . If the upper limit of condition (1) is exceeded, the effective diameter of the lens element closest to the enlargement side becomes too large. On the other hand, when the value is below the lower limit value, the effective diameter of the positive power lens element that is closer to the enlargement side than the intermediate imaging position and is closest to the intermediate imaging position becomes too large. That is, the effective diameter of the lens element of the magnifying optical system Op, which tends to be large in the fisheye lens, can be reduced by designing in the range of the condition (1).

  In addition, the said effect can be further achieved by satisfying at least one of the following conditions (1A) and (1B).

0.15 ≦ fp / fr (1A)
fp / fr ≦ 0.7 (1B)
Furthermore, by satisfying at least one of the following conditions (1C) and (1D), the above effect can be further achieved.

0.18 ≦ fp / fr (1C)
fp / fr ≦ 0.6 (1D)
Condition (2) represents distortion in a normal optical system with respect to the effective image circle diameter. By satisfying this condition, a wide-angle lens system can be realized. If the upper limit of condition (2) is exceeded, it becomes difficult to widen the angle.

  For example, a lens system having a basic configuration like the lens systems according to Embodiments 1 to 11 preferably satisfies the following condition (3).

0.4 ≦ fpf / (ft · ωmax · π / 180) ≦ 1.8 (3)
here,
fpf: the combined focal length of the front group of the magnifying optical system.

  Condition (3) defines the relationship between the combined focal length of the magnifying optical system and the ideal image height in equidistant projection. By satisfying this condition, lateral chromatic aberration can be suppressed. If the upper limit of the condition (3) is exceeded, the lateral chromatic aberration will increase. Conversely, if the lower limit is exceeded, the lateral chromatic aberration will similarly increase.

  In addition, the above effect can be further achieved by further satisfying at least one of the following conditions (3A) and (3B).

0.6 ≦ fpf / (ft · ωmax · π / 180) (3A)
fpf / (ft · ωmax · π / 180) ≦ 1.6 (3B)
For example, a lens system having a basic configuration like the lens systems according to Embodiments 1 to 11 preferably satisfies the following condition (4).

60 <| (Lt · ft · ωmax · π / 180) / ft ² | <200 (4)
here,
Lt: The optical total length of the lens system.

  Condition (4) is a conditional expression that defines the relationship between a value obtained by normalizing the entire length of the lens system with the focal length and a value obtained by normalizing the ideal image height in equidistant projection with the focal length. If the upper limit of condition (4) is exceeded, the total length becomes too long. Conversely, if the lower limit is exceeded, lateral chromatic aberration increases.

  In addition, the said effect can be further achieved by satisfying at least one of the following conditions (4A) and (4B).

70 <| (Lt · ft · ωmax · π / 180) / ft ² | (4A)
| (Lt · ft · ωmax · π / 180) / ft ² | <160 (4B)
For example, a lens system having a basic configuration like the lens systems according to Embodiments 1 to 11 preferably satisfies the following condition (5).

| T / ft | ≦ 3.0 (5)
here,
t: Distance on the optical axis between the most demagnifying lens surface of the front group of the magnifying optical system and the most enlarging lens surface of the rear group of the magnifying optical system.

  Condition (5) is that the distance on the optical axis between the most demagnifying lens surface of the front group of the magnifying optical system and the most enlarging lens surface of the rear group of the magnifying optical system, and the focal length of the entire lens system It is a conditional expression that defines the relationship. By satisfying this relationship, the effective diameter of the lens element located on the most enlarged side can be reduced. If the upper limit is exceeded, the effective diameter of the lens element on the most magnified side will be too large.

  In addition, the said effect can be further achieved by satisfying the following conditions (5A).

| T / ft | ≦ 2.5 (5A)
For example, a lens system having a basic configuration like the lens systems according to Embodiments 1 to 11 preferably satisfies the following condition (6).

36 <| (Lr · ft · ωmax · π / 180) / ft ² | <150 (6)
here,
Lr: distance on the optical axis from the intermediate image forming position to the image forming position on the reduction side.

  Condition (6) is a value obtained by normalizing the distance on the optical axis from the intermediate image forming position to the image forming position on the reduction side with the focal length, and a value obtained by normalizing the ideal image height in equidistant projection with the focal length output. Is a conditional expression that defines the relationship between By satisfying this condition, it is possible to suppress lateral chromatic aberration while reducing the overall length. If the upper limit of condition (6) is exceeded, the overall length becomes too long. Conversely, if the lower limit is exceeded, lateral chromatic aberration increases.

  In addition, the said effect can be further achieved by satisfying at least one of the following conditions (6A) and (6B).

40 <| (Lr · ft · ωmax · π / 180) / ft ² | (6A)
| (Lr · ft · ωmax · π / 180) / ft ² | <120 (6B)
For example, a lens system having a basic configuration like the lens systems according to Embodiments 1 to 11 preferably satisfies the following condition (7).

2.9 <SFL1 <5.0 (7)
here,
SFL1: A shape factor of the lens element on the most enlargement side in the lens system.

  Condition (7) defines the shape factor of the lens element on the most enlarged side of the lens system. If the upper limit of condition (7) is exceeded, the effective diameter of the lens element on the most magnified side will be large, and conversely if below the lower limit, the lens element on the most magnified side will be difficult to manufacture. .

  In addition, the above effect can be further achieved by further satisfying at least one of the following conditions (7A) and (7B).

3.0 <SFL1 (7A)
SFL1 <4.5 (7B)
For example, as in the lens systems according to Embodiments 1 to 7, a field curvature correction group that has a basic configuration and moves along the optical axis when adjusting the field curvature amount to the rear group of the magnifying optical system. It is preferable that the lens system having the lens system satisfies the following condition (8).

10 <| fas / (ft · ω · π / 180) | <1000 (8)
here,
fas: the combined focal length of the field curvature correction group.

  Condition (8) defines the relationship between the combined focal length of the field curvature correction group and the ideal image height in equidistant projection. By satisfying this condition, it is possible to correct the curvature of field while suppressing a change in back focus while being small. If the upper limit of the condition (8) is exceeded, the amount of movement of the field curvature correction group becomes too large to correct the field curvature, and the total length becomes large. The back focus changes due to the movement of the correction group, and as the field curvature correction group moves, it is necessary to adjust the back focus, which takes time and effort to correct the field curvature.

  In addition, the above effect can be further achieved by further satisfying at least one of the following conditions (8A) and (8B).

30 <| fas / (ft · ω · π / 180) | (8A)
| Fas / (ft · ω · π / 180) | <700 (8B)
For example, a lens system having a basic configuration like the lens systems according to Embodiments 1 to 11 preferably satisfies the following condition (9).

2 <| f1 / (f · ω · π / 180) | <10 (9)
here,
f1: It is the focal length of the lens element located closest to the magnification side in the lens system.

  Condition (9) defines the relationship between the focal length of the lens element closest to the magnification side in the lens system and the ideal image height in equidistant projection. By satisfying this condition, it is possible to suppress an increase in the size of the lens element located on the most enlarged side with a wide angle of view. If the upper limit of the condition (9) is exceeded, the effective diameter of the lens element on the most magnified side will be large, and conversely if below the lower limit, the power of the lens element on the most magnified side will be too weak and widening the angle. In order to achieve this, the lens shape becomes difficult to manufacture.

  In addition, the above effect can be further achieved by further satisfying at least one of the following conditions (9A) and (9B).

3 <| f1 / (f · ω · π / 180) | (9A)
| F1 / (f · ω · π / 180) | <8 (9B)
For example, a lens system having a basic configuration like the lens systems according to Embodiments 1 to 11 preferably satisfies the following condition (10).
0.8 <φpfmax / φprmax <1.3 (10)
here,
φpfmax: Maximum lens effective diameter of the lens element in the front group of the magnifying optical system φprmax: Maximum lens effective diameter of the lens element in the rear group of the magnifying optical system.

  Condition (10) is a conditional expression for defining the ratio between the maximum lens effective diameter of the lens elements in the front group of the magnifying optical system and the maximum lens effective diameter of the lens elements in the rear group of the magnifying optical system. is there. If the upper limit is exceeded, the effective diameter of the lens element that is closest to the enlargement side becomes too large. Conversely, if the lower limit is exceeded, the effective diameter of the lens element that is on the enlargement side due to the intermediate imaging position and is close to the intermediate imaging position Becomes too big.

  In addition, the above effect can be further achieved by further satisfying at least one of the following conditions (10A) and (10B).

0.9 <φpfmax / φprmax (10A)
φpfmax / φprmax <1.2 (10B)
As described above, the embodiments have been described as examples of the technology disclosed in the present application. However, the technology in the present disclosure is not limited to this, and can also be applied to an embodiment in which changes, replacements, additions, omissions, and the like are appropriately performed.

  Hereinafter, numerical examples of the lens systems of Examples 1 to 11 will be described. In each numerical example, the unit of length in the table is “mm”, and the unit of angle of view is “°”. In each numerical example, r is a radius of curvature, d is a surface interval, nd is a refractive index with respect to the d line, and vd is an Abbe number with respect to the d line.

(Numerical example 1)
Table 1 shows surface data, Table 2 shows various data, and Table 3 shows single lens data for the lens system of Numerical Example 1 (corresponding to Embodiment 1).

(Numerical example 2)
Table 4 shows surface data, Table 5 shows various data, and Table 6 shows single lens data for the lens system of Numerical Example 2 (corresponding to Embodiment 2).

(Numerical Example 3)
Table 7 shows surface data, Table 8 shows various data, and Table 9 shows single lens data for the lens system of Numerical Example 3 (corresponding to Embodiment 3).

(Numerical example 4)
Table 10 shows surface data, Table 11 shows various data, and Table 12 shows single lens data for the lens system of Numerical Example 4 (corresponding to Embodiment 4).

(Numerical example 5)
Table 13 shows surface data, Table 14 shows various data, and Table 15 shows single lens data for the lens system of Numerical Example 5 (corresponding to Embodiment 5).

(Numerical example 6)
Table 16 shows surface data, Table 17 shows various data, and Table 18 shows single lens data for the lens system of Numerical Example 6 (corresponding to Embodiment 6).

(Numerical example 7)
Table 19 shows surface data, Table 20 shows various data, and Table 21 shows single lens data for the lens system of Numerical Example 7 (corresponding to Embodiment 7).

(Numerical example 8)
Table 22 shows surface data, Table 23 shows various data, and Table 24 shows single lens data for the lens system of Numerical Example 8 (corresponding to Embodiment 8).

(Numerical Example 9)
Table 25 shows surface data, Table 26 shows various data, and Table 27 shows single lens data for the lens system of Numerical Example 9 (corresponding to Embodiment 9).

(Numerical Example 10)
Table 28 shows surface data, Table 29 shows various data, and Table 30 shows single lens data for the lens system of Numerical Example 10 (corresponding to Embodiment 10).

(Numerical Example 11)
Table 31 shows surface data, Table 32 shows various data, and Table 33 shows single lens data for the lens system of Numerical Example 11 (corresponding to Embodiment 11).

  Table 34 below shows corresponding values of the conditions in the lens systems of the numerical examples.

(Other embodiments)
In the first to eleventh embodiments, the case where the lens system of the present disclosure is used in a projector has been described. However, the lens system of the present disclosure receives an optical image formed by the lens system and converts it into an electrical image signal. It can be used for an imaging device by combining with an imaging element that performs the above.

  The present disclosure can be applied to an image projection apparatus such as a projector or a head-up display, an imaging apparatus such as a digital still camera, a digital video camera, a surveillance camera in a surveillance system, a Web camera, or an in-vehicle camera. In particular, the present disclosure can be applied to a photographing optical system that requires high image quality, such as a projector, a digital still camera system, and a digital video camera system.

L1 1st lens element L2 2nd lens element L3 3rd lens element L4 4th lens element L5 5th lens element L6 6th lens element L7 7th lens element L8 8th lens element L9 9th lens element L10 10th lens element L11 11th lens element L12 12th lens element L13 13th lens element L14 14th lens element L15 15th lens element L16 16th lens element L17 17th lens element L18 18th lens element L19 19th lens element L20 20th lens element L21 21st lens element L22 22nd lens element L23 23rd lens element L24 24th lens element L25 25th lens element A Aperture MI Intermediate imaging position Ol Relay optical system Op Enlarging optical system Opf Enlarging optical system front group Opr Enlarging optical Rear group of system P Optical element S Image

Claims (12)

A lens system that conjugates the magnification conjugate point on the magnification side and the reduction conjugate point on the reduction side with an intermediate imaging position inside the lens system,
A positive power magnifying optical system having a plurality of lens elements and located on the magnifying side from the intermediate imaging position;
A positive optical relay optical system having a plurality of lens elements and located on the reduction side from the intermediate imaging position,
A lens system that satisfies the following conditions (1) and (2):
0.08 ≦ fp / fr ≦ 0.8 (1)
{Ymax−ft · tan (ωmax)} / {ft · tan (ωmax)} ≦ −0.3
... (2)
here,
fr: Composite focal length of relay optical system on the reduction side with respect to the intermediate imaging position fp: Composite focal length of enlargement optical system on the enlargement side with respect to the intermediate imaging position Ymax: Radius of effective image circle diameter ωmax: Half maximum Angle of view ft: The focal length of the entire lens system. The magnifying optical system includes a positive power lens element, and is arranged after the magnifying optical system including a lens element on the reduction side from the positive power lens element arranged on the most magnifying side of the magnifying optical system. A group and a front group of the magnifying optical system composed of lens elements on the magnifying side of the positive power lens element arranged on the most magnifying side of the magnifying optical system,
The lens system according to claim 1, satisfying the following condition (3):
0.4 ≦ fpf / (ft · ωmax · π / 180) ≦ 1.8 (3)
here,
fpf: the combined focal length of the front group of the magnifying optical system. The lens system according to claim 1, wherein the lens system satisfies the following condition (4):
60 <| (Lt · ft · ωmax · π / 180) / ft ² | <200 (4)
here,
Lt: The optical total length of the lens system. The magnifying optical system includes a positive power lens element, and is arranged after the magnifying optical system including a lens element on the reduction side from the positive power lens element arranged on the most magnifying side of the magnifying optical system. A group and a front group of the magnifying optical system composed of lens elements on the magnifying side of the positive power lens element arranged on the most magnifying side of the magnifying optical system,
The lens system according to any one of claims 1 to 3, wherein the following condition (5) is satisfied:
| T / ft | ≦ 3.0 (5)
here,
t: Distance on the optical axis between the most demagnifying lens surface of the front group of the magnifying optical system and the most enlarging lens surface of the rear group of the magnifying optical system. The lens system according to any one of claims 1 to 4, which satisfies the following condition (6):
36 <| (Lr · ft · ωmax · π / 180) / ft ² | <150 (6)
here,
Lr: distance on the optical axis from the intermediate image forming position to the image forming position on the reduction side. The front group of the magnifying optical system includes, in order from the magnifying side to the reducing side, a negative meniscus first lens element having a convex surface on the magnifying side and a negative meniscus second lens element having a convex surface on the magnifying side. And having
The lens system according to claim 1. The lens system according to any one of claims 1 to 6, which satisfies the following condition (7):
2.9 <SFL1 <5.0 (7)
here,
SFL1: A shape factor of the lens element on the most enlargement side in the lens system. The magnifying optical system includes a positive power lens element, and is arranged after the magnifying optical system including a lens element on the reduction side from the positive power lens element arranged on the most magnifying side of the magnifying optical system. A group and a front group of the magnifying optical system composed of lens elements on the magnifying side of the positive power lens element arranged on the most magnifying side of the magnifying optical system,
The rear group of the magnifying optical system has a field curvature correction lens group that moves in the optical axis direction when adjusting the amount of field curvature,
The lens system according to any one of claims 1 to 7, which satisfies the following condition (8):
10 <| fas / (ft · ω · π / 180) | <1000 (8)
here,
fas: the combined focal length of the field curvature correcting lens group. The lens system according to any one of claims 1 to 8, which satisfies the following condition (9):
2 <| f1 / (f · ω · π / 180) | <10 (9)
here,
f1: It is the focal length of the lens element located closest to the magnification side in the lens system. The magnifying optical system includes a positive power lens element, and is arranged after the magnifying optical system including a lens element on the reduction side from the positive power lens element arranged on the most magnifying side of the magnifying optical system. A group and a front group of the magnifying optical system composed of lens elements on the magnifying side of the positive power lens element arranged on the most magnifying side of the magnifying optical system,
The lens system according to any one of claims 1 to 9, which satisfies the following condition (10):
0.8 <φpfmax / φprmax <1.3 (10)
here,
φpfmax: Maximum lens effective diameter of the lens element in the front group of the magnifying optical system φprmax: Maximum lens effective diameter of the lens element in the rear group of the magnifying optical system. The lens system according to any one of claims 1 to 10,
An image forming element that generates an image to be projected on a screen;
Image projection device. The lens system according to any one of claims 1 to 10,
An imaging device comprising: an imaging element that receives an optical image formed by the lens system and converts the optical image into an electrical image signal.

Images