Optical system and projector

Abstract

To provide an optical system of an ultra short focus system in which a curvature of field easily occurs.SOLUTION: An optical system comprises: a first optical system that has a first optical element; and a second optical system that is arranged on a reduction side of the first optical system. An intermediate image conjugate with a reduction-side conjugate surface and an enlargement-side conjugate surface is formed between the first optical system and the second optical system. The first optical element has a first reflection surface with a concave shape. The second optical system has a first relay element, a second relay element that is arranged on an enlargement side of the first relay element, and a correction optical element that is arranged on the enlargement side of the first relay element. The first relay element has a first relay reflection surface with a concave shape. The second relay element has a second relay reflection surface with a convex shape. The correction optical element curves the intermediate image created by the first relay element and the second relay element to reduce a curvature of field generated by the first optical element.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an optical system and a projector. [Background technology]

[0002] A projection optical system that forms an intermediate image between a reduction-side image forming surface and a magnification-side image forming surface is described in Patent Document 1. The projection optical system in this document includes a relay optical system with a life-size magnification that forms an intermediate image conjugate with the reduction-side image forming surface, and an magnification optical system that enlarges and projects the intermediate image. The relay optical system includes a first lens element with positive refractive power, a reflecting member with positive refractive power, and a second lens element with positive refractive power. Light from the reduction-side image forming surface side passes through the first lens element and is reflected by the reflecting member. The light reflected by the reflecting member passes through the second lens element to form an intermediate image. The first lens element and the second lens element are formed as an integrated lens element with positive refractive power. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-138086 Summary of the Invention [Problem to be solved by the invention]

[0004] In the projection optical system of Patent Document 1, the intermediate image is the same size as the reduction-side conjugate plane and there is almost no curvature of field. Therefore, it is difficult to use an ultra-short focus optical system, which is prone to curvature of field, as the magnifying optical system. [Means for solving the problem]

[0005] In order to solve the above problem, the optical system of the present invention projects a projected image formed on a reduction-side conjugate plane as an enlarged image onto an enlargement-side conjugate plane, and includes a first optical system having a first optical element and a second optical system arranged on the reduction-side of the first optical system, and an intermediate image conjugate to the reduction-side conjugate plane and the enlargement-side conjugate plane is formed between the first optical system and the second optical system, the first optical element having a concave first reflecting surface, the second optical system having a first relay element, a second relay element arranged on the enlargement side of the first relay element, and a correction optical element arranged on the enlargement side of the first relay element, the first relay element having a concave first relay reflecting surface, and the second relay element having a second relay reflecting surface, and the correction optical element curves the intermediate image generated by the first relay element and the second relay element to reduce the field curvature caused by the first optical element.

[0006] Next, a projector of the present invention includes a light modulation element disposed on the reduction-side conjugate plane and modulating light emitted from a light source, and the above-described optical system that projects the light modulated by the light modulation element. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram showing a schematic configuration of a projector including an optical system according to an embodiment of the present invention. [Figure 2] 1 is a ray diagram schematically illustrating the entire optical system of Example 1. FIG. [Figure 3] FIG. 2 is a ray diagram of the optical system of the first embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] An optical system and a projector according to an embodiment of the invention will be described below with reference to the drawings.

[0009] (projector) 1 is a diagram showing a schematic configuration of a projector equipped with an optical system 3 of the present invention. As shown in Fig. 1, the projector 1 is equipped with an image forming unit 2 that generates a projection image to be projected onto a screen S, an optical system 3 that enlarges the projection image and projects the enlarged image onto the screen S, and a control unit 4 that controls the operation of the image forming unit 2.

[0010] (Image forming unit and control unit) The image forming unit 2 includes a light source 10, a first integrator lens 11, a second integrator lens 12, a polarization conversion element 13, and a superimposing lens 14. The light source 10 is, for example, an ultra-high pressure mercury lamp, a solid-state light source, or the like. The first integrator lens 11 and the second integrator lens 12 each have a plurality of lens elements arranged in an array. The first integrator lens 11 splits the light beam from the light source 10 into a plurality of beams. Each lens element of the first integrator lens 11 focuses the light beam from the light source 10 near each lens element of the second integrator lens 12.

[0011] Polarization conversion element 13 converts the light from second integrator lens 12 into predetermined linearly polarized light. Superimposing lens 14 superimposes the images of each lens element of first integrator lens 11 via second integrator lens 12 onto the display areas of liquid crystal panels 18R, 18G, and 18B, which will be described later.

[0012] The image forming unit 2 also includes a first dichroic mirror 15, a reflecting mirror 16, a field lens 17R, and a liquid crystal panel 18R. The first dichroic mirror 15 reflects R light, which is a portion of the light incident from the superimposing lens 14, and transmits G light and B light, which are also portions of the light incident from the superimposing lens 14. The R light reflected by the first dichroic mirror 15 passes through the reflecting mirror 16 and the field lens 17R and is incident on the liquid crystal panel 18R. The liquid crystal panel 18R is a light modulation element. The liquid crystal panel 18R modulates the R light in accordance with an image signal to form a red projection image.

[0013] The image forming unit 2 further includes a second dichroic mirror 21, a field lens 17G, and a liquid crystal panel 18G. The second dichroic mirror 21 reflects G light, which is a portion of the light from the first dichroic mirror 15, and transmits B light, which is a portion of the light from the first dichroic mirror 15. The G light reflected by the second dichroic mirror 21 passes through the field lens 17G and enters the liquid crystal panel 18G. The liquid crystal panel 18G is a light modulation element. The liquid crystal panel 18G forms a green projection image by modulating the G light in accordance with an image signal.

[0014] The image forming unit 2 also includes a relay lens 22, a reflecting mirror 23, a relay lens 24, a reflecting mirror 25, a field lens 17B, a liquid crystal panel 18B, and a cross dichroic prism 19. The B light transmitted through the second dichroic mirror 21 passes through the relay lens 22, the reflecting mirror 23, the relay lens 24, the reflecting mirror 25, and the field lens 17B, and is incident on the liquid crystal panel 18B. The liquid crystal panel 18B is a light modulation element. The liquid crystal panel 18B forms a blue projection image by modulating the B light in accordance with an image signal.

[0015] Liquid crystal panels 18R, 18G, and 18B surround cross dichroic prism 19 on three sides. Cross dichroic prism 19 is a prism for light synthesis, and generates a projection image by synthesizing the light modulated by each of liquid crystal panels 18R, 18G, and 18B.

[0016] The optical system 3 projects the projection image synthesized by the cross dichroic prism 19 onto the screen S in an enlarged scale.

[0017] The control unit 4 includes an image processing unit 6 to which external image signals such as video signals are input, and a display driving unit 7 that drives the liquid crystal panels 18R, 18G, and 18B based on the image signals output from the image processing unit 6.

[0018] Image processing unit 6 converts an image signal input from an external device into an image signal including the gradation of each color. Display drive unit 7 operates liquid crystal panels 18R, 18G, and 18B based on the projection image signals of each color output from image processing unit 6. As a result, image processing unit 6 displays a projection image corresponding to the image signal on liquid crystal panels 18R, 18G, and 18B.

[0019] (optical system) Fig. 2 is a ray diagram showing a schematic representation of the entire optical system. Fig. 3 is a ray diagram of the optical system. As shown in Figs. 2 and 3, a liquid crystal panel 18 is disposed on the reduction-side conjugate plane of the optical system 3.

[0020] For convenience, in the following description, three mutually perpendicular axes are referred to as the X-axis, Y-axis, and Z-axis. The width direction of the screen S, which is the magnification-side conjugate plane, is referred to as the X-axis direction, the vertical direction of the screen S as the Y-axis direction, and the direction perpendicular to the screen S as the Z-axis direction. In the Y-axis direction, the direction above the screen S is referred to as the Y1 direction, and the direction below the screen S as the Y2 direction. In the Z-axis direction, the side where the screen S is located is referred to as the Z1 direction, and the opposite side is referred to as the Z2 direction.

[0021] 2, the optical system 3 of this example includes, in order from the enlargement side to the reduction side, a first optical system 31 and a second optical system 32. The first optical system 31 and the second optical system 32 are arranged along the Y-axis direction. The screen S is located in the Z1 direction of the optical system 3.

[0022] Next, we will explain the specific configuration of the optical system 3 of this example. As shown in Figure 3, the optical system 3 includes, in order from the enlargement side to the reduction side, a first optical element 33, a second optical element 34, a correction optical element 36, a second relay element 37, and a first relay element 38.

[0023] The first optical element 33 consists of one optical element. The first optical element 33 is located in the Z2 direction of the second optical element 34. The first optical element 33 has a first transmitting surface 41, a first reflecting surface 42 located on the reduction side of the first transmitting surface 41, and a second transmitting surface 43 located on the reduction side of the first reflecting surface 42.

[0024] The first transmitting surface 41 has a convex shape facing the Y1 direction. The first transmitting surface 41 has positive power. The first transmitting surface 41 has an aspherical shape.

[0025] The first reflecting surface 42 is located in the Y2 direction of the first transmitting surface 41. The first reflecting surface 42 has a concave shape recessed in the Z2 direction and has positive power. The first reflecting surface 42 has an aspherical shape. The first reflecting surface 42 is formed by providing a reflective coating layer on the outer surface of the first optical element 33 in the Z2 direction.

[0026] The second transmitting surface 43 has a convex shape facing the Z1 direction. The second transmitting surface 43 has positive power. The second transmitting surface 43 has an aspherical shape.

[0027] The second optical element 34 is composed of a single optical element. The second optical element 34 is located in the Z1 direction of the first optical element 33. The second optical element 34 has a third transmitting surface 51, a second reflecting surface 52 located on the reduction side of the third transmitting surface 51, and a fourth transmitting surface 53 located on the reduction side of the second reflecting surface 52.

[0028] The third transmitting surface 51 faces the second transmitting surface 43 in the Z-axis direction. The third transmitting surface 51 has a convex shape facing the Z2 direction and has positive power. The third transmitting surface 51 has an aspherical shape.

[0029] The second reflecting surface 52 is a flat mirror with no power. The second reflecting surface 52 is inclined at 45° with respect to the Y-axis and the Z-axis. The second reflecting surface 52 bends the optical path by 90° between the third transmitting surface 51 and the fourth transmitting surface 53. The second reflecting surface 52 is formed by providing a reflective coating layer on the outer surface of the second optical element 34 in the Z1 direction.

[0030] The fourth transmitting surface 53 faces in the Y2 direction. The fourth transmitting surface 53 has positive power. The fourth transmitting surface 53 has an aspherical shape.

[0031] The correction optical element 36 is made of a resin lens. The correction optical element 36 is located in the Y2 direction of the second optical element 34. The correction optical element 36 has negative power. The correction optical element 36 has a first surface 71 on the magnification side that is convex, and a second surface 72 on the reduction side that is concave. The first surface 71 and the second surface 72 have aspherical shapes.

[0032] The second relay element 37 is located in the Y2 direction of the correction optical element 36. The second relay element 37 has a second relay reflecting surface 73. The second relay reflecting surface 73 has a convex shape. The second relay reflecting surface 73 has an aspheric shape.

[0033] The first relay element 38 is located in the Y1 direction of the second relay element 37. The first relay element 38 has a first relay reflecting surface 74. The first relay reflecting surface 74 has a concave shape. The first relay reflecting surface 74 has an aspherical shape.

[0034] In this example, the first optical element 33 and the third transmitting surface 51 of the second optical element 34 constitute the first optical system 31. The fourth transmitting surface 53 of the second optical element 34, the correction optical element 36, the second relay element 37, and the first relay element 38 constitute the second optical system 32. The second optical system 32 is a relay optical system.

[0035] 2, the liquid crystal panel 18, which is disposed on the reduction-side conjugate plane of the optical system 3, forms a projected image. After passing through the second optical system 32, light from the liquid crystal panel 18 side is bent 90 degrees by the second reflecting surface 52 of the second optical element 34 and headed in the Z2 direction. The light headed in the Z2 direction is bent by the first reflecting surface 42 of the first optical element 33 in the Z1 and Y1 directions and reaches the screen S.

[0036] 2 and 3 , the optical system 3 forms an intermediate image 30 conjugate with the magnification-side conjugate plane and the reduction-side conjugate plane between the first optical system 31 and the second optical system 32. In this example, the intermediate image 30 is formed between the third transmitting surface 51 of the second optical element 34 and the second reflecting surface 52 of the second optical element 34. At this time, since the corrective optical element 36 is a lens having power, the corrective optical element 36 curves and magnifies the intermediate image 30 generated by the first relay element 38 and the second relay element 37. Since the fourth transmitting surface 53 has power, the fourth transmitting surface 53 curves and magnifies the intermediate image 30 generated by the corrective optical element 36.

[0037] 2 and 3, if a virtual axis V is a line connecting a first intersection V1 where a chief ray F at an image height corresponding to the center of the enlarged image projected onto the screen S intersects with the second reflecting surface 52 and a second intersection V2 where the chief ray F intersects with the liquid crystal panel 18, the virtual axis V is parallel to the screen S. Here, the image height corresponding to the center of the enlarged image refers to the image height at the center of the enlarged image in the Y-axis and X-axis directions.

[0038] The lens data for optical system 3 is as follows. Surface numbers are assigned in order from the reduction side to the magnification side. The symbols refer to the liquid crystal panel, dichroic prism, lens, and screen. Data for surface numbers that do not correspond to the liquid crystal panel, dichroic prism, lens, and screen are dummy data. Surfaces with an * next to the surface number are aspheric. R is the radius of curvature. D is the on-axis surface spacing. nd is the refractive index. νd is the Abbe number. Y is the aperture radius. The units for R, D, and Y are mm. The lens data in this example was designed using CODE V by Synopsys.

[0039] Sign Surface No. RD nd vd Mode Y 18 0 0.00000 22.000000 Refraction 19 1 0.00000 37.300000 1.516800 64.17 Refraction 19.5290 2 0.00000 131.867527 Refraction 20.8530 38 *3 -209.12031 -145.000000 Reflection 28.1090 37 *4 -385.71827 66.496815 Reflection 20.0000 36 *5 -110.41423 28.901060 1.509398 56.47 Refraction 27.5930 *6 -122.04370 109.288489 Refraction 27.1590 34 *7 5510.58422 82.175433 1.509398 56.47 Refraction 59.4390 8 0.00000 -17.756111 1.509398 56.47 Reflection 84.0620 *9 -104.13541 -3.819383 Refraction 66.6210 33 *10 -66.33908 -130.000000 1.509398 56.47 Refraction 55.9260 *11 36.50445 0.000000 1.509398 56.47 Reflection 54.8470 *12 -70.00000 0.000000 Refraction 45.6220 13 0.00000 0.000000 Refraction 1899.6260 S 14 0.00000 0.000000 Refraction 2140.4110

[0040] The aspherical coefficients are as follows:

[0041] Face number 3 4 5 6 Conic constant 1.396563E+01 0 -6.289454E+00 8.223611E+00 4th order coefficient 1.838498E-07 -1.570685E-07 -3.731301E-07 4.325503E-07 6th order coefficient 3.818978E-11 2.731995E-11 -1.473192E-11 3.231727E-10 8th order coefficient 3.335276E-15 -2.695231E-13 1.198218E-14 -3.663914E-13 10th order coefficient 4.333801E-18 2.674525E-16 -1.184285E-16 2.484916E-16

[0042] Face number 7 9 10 11 Conic constant 6E+01 -4.686224E-02 6.538515E-02 -1.662726E+00 4th order coefficient -4.450294E-07 5.883883E-06 9.967068E-07 -1.300763E-06 6th order coefficient 3.101317E-10 -1.450153E-09 1.399283E-09 2.646661E-10 8th order coefficient -5.044936E-14 1.776836E-13 -5.306366E-13 -8.123003E-15 10th order coefficient 0 -8.00476E-18 7.865811E-17 -1.278694E-18

[0043] Face number 12 Conic constant 0 4th order coefficient 5.316967E-09 6th order coefficient -6.475294E-12 8th order coefficient 3.281491E-15 10th order coefficient -5.46149E-19

[0044] The ray coordinates at the object plane are:

[0045] Ray number X coordinate Y coordinate 1 0 -17.20 2 0 -15.20 3 0 -13.20 4 0 -11.20 5 0 -9.20 6 1.60 -17.20 7 1.60 -15.20 8 1.60 -13.20 9 1.60 -11.20 10 1.60 -9.20 11 3.20 -17.20 12 3.20 -15.20 13 3.20 -13.20 14 3.20 -11.20 15 3.20 -9.20 16 4.80 -17.20 17 4.80 -15.20 18 4.80 -13.20 19 4.80 -11.20 20 4.80 -9.20 21 6.40 -17.20 22 6.40 -15.20 23 6.40 -13.20 24 6.40 -11.20 25 6.40 -9.20

[0046] In this example, the decentered surfaces have surface numbers 3, 4, 5, 6, 7, 8, 10, 11, 12, 13, and 14. The parameters of the decentered surfaces are as follows:

[0047] Face number 3 Eccentricity type: Decenter and bend Parameter X 0.0000 Parameter Y 0.0000 Parameter Z 0.0000 Parameter α -5.0000

[0048] Face number 4 Eccentricity type: Decenter and bend Parameter X 0.0000 Parameter Y 0.0000 Parameter Z 0.0000 Parameter α 9.0000

[0049] Face number 5 Eccentricity type: Normal Parameter X 0.0000 Parameter Y 7.6642 Parameter Z 0.0000 Parameter α 38.5647

[0050] Face number 6 Eccentricity type: Normal Parameter X 0.0000 Parameter Y -5.7937 Parameter Z 0.0000 Parameter α 0.0000

[0051] Face number 7 Eccentricity type: Normal Parameter X 0.0000 Parameter Y -101.0137 Parameter Z 0.0000 Parameter α -32.2800

[0052] Face number 8 Eccentricity type: Decenter and bend Parameter X 0.0000 Parameter Y 0.0000 Parameter Z 0.0000 Parameter α 45.0000

[0053] Face number 10 Eccentricity type: Normal Parameter X 0.0000 Parameter Y -3.6080 Parameter Z 0.0000 Parameter α 4.8964

[0054] Face number 11 Eccentricity type: Normal Parameter X 0.0000 Parameter Y 0.0000 Parameter Z 81.0000 Parameter α 2.0299

[0055] Face number 12 Eccentricity Type Global Coordinates Global Reference Plane 11 Parameter X 0.0000 Parameter Y -70.0000 Parameter Z 37.9493 Parameter α -90.0000

[0056] Face number 13 Eccentricity Type Global Coordinates Global Reference Plane 11 Parameter X 0.0000 Parameter Y 0.0000 Parameter Z 600.0000 Parameter α 0.0000

[0057] Face number 14 Eccentricity type: Decenter and bend Parameter X 0.0000 Parameter Y 0.0000 Parameter Z 0.0000 Parameter α 2.0197

[0058] (Action and effect) The optical system 3 of this example includes a first optical system 31 having a first optical element 33 and a second optical system 32 arranged on the reduction side of the first optical system 31. An intermediate image 30 conjugate to the reduction-side conjugate plane and the magnification-side conjugate plane is formed between the first optical system 31 and the second optical system 32. The first optical element 33 has a concave first reflecting surface 42. The second optical system 32 has a first relay element 38, a second relay element 37 arranged on the magnification side of the first relay element 38, and a correcting optical element 36 arranged on the magnification side of the first relay element. The first relay element 38 has a concave first relay reflecting surface 74. The second relay element 37 has a convex second relay reflecting surface 73. The correcting optical element 36 curves the intermediate image 30 generated by the first relay element 38 and the second relay element 37 to reduce the field curvature caused by the first optical element 33.

[0059] According to the present invention, the first optical system 31 disposed on the enlarged side of the intermediate image 30 includes the first optical element 33 having a concave first reflecting surface 42. Therefore, by increasing the power of the first reflecting surface 42, the focal length of the optical system 3 can be shortened. Here, increasing the power of the first optical element 33 causes field curvature, but this field curvature can be reduced by the correction optical element 36. Therefore, the field curvature occurring in the enlarged image formed on the screen S can be suppressed. Furthermore, because the concave first reflecting surface 42 is used to enlarge the intermediate image 30, the optical system 3 can be prevented from becoming larger in size compared to when the intermediate image 30 is enlarged using a lens with a convex transmitting surface or a reflecting member with a convex reflecting surface.

[0060] Furthermore, the second relay reflecting surface 73 has a convex shape. That is, the second relay reflecting surface 73 has power. Therefore, the second relay reflecting surface 73 can curve the intermediate image 30. This allows both the second relay reflecting surface 73 and the correction optical element 36 to share the function of reducing the field curvature caused by the first optical element 33.

[0061] In this example, the correction optical element 36 is a lens made of resin. Therefore, a complex shape can be used for each transmitting surface of the correction optical element 36. This makes it easy to reduce the curvature of field caused by the first optical element 33, making it easier to shorten the focal length of the optical system. In addition, the correction optical element 36 has aspherical shapes on both sides. Therefore, various aberrations in the intermediate image 30 can be corrected.

[0062] In this example, the first optical element 33 includes a first transmitting surface 41, a first reflecting surface 42 disposed on the reduction side of the first transmitting surface 41, and a second transmitting surface 43 disposed on the reduction side of the first reflecting surface 42. Therefore, the second transmitting surface 43 can control the light rays traveling from the intermediate image 30 side toward the first reflecting surface 42. In other words, the amount of field curvature of the intermediate image 30 formed on the reduction side of the first reflecting surface 42 can be controlled. This makes it possible to suppress an increase in the amount of field curvature of the intermediate image 30 generated in the first optical system, making it easier to shorten the focal length of the optical system 3. This also reduces the burden of field curvature correction on the second optical system 32 side.

[0063] In this example, the first transmitting surface 41 and the second transmitting surface 43 have aspherical shapes, which makes it easier to correct various aberrations in the magnified image.

[0064] Furthermore, in this example, if a line connecting a first intersection V1 where a chief ray F at an image height corresponding to the center of the enlarged image projected onto the screen S intersects with the second reflecting surface 52 and a second intersection V2 where the chief ray F intersects with the liquid crystal panel 18 is defined as a virtual axis V, the virtual axis V is parallel to the screen S. This allows optical elements arranged on the reduction side of the second optical element 34 having the second reflecting surface 52 to be arranged parallel to the enlargement-side image forming surface. This prevents optical elements arranged on the reduction side of the second optical element 34 from interfering with the enlargement-side image forming surface. This makes it possible to install the optical system 3 in a position close to the screen S.

[0065] This example also includes a second optical element 34 having a second reflecting surface 52. The second optical element 34 includes a third transmitting surface 51, a second reflecting surface 52 disposed on the reduction side of the third transmitting surface 51, and a fourth transmitting surface 53 disposed on the reduction side of the second reflecting surface. The third transmitting surface 51 constitutes the first optical system 31, and the fourth transmitting surface 53 constitutes the second optical system 32. The intermediate image 30 is formed between the second reflecting surface 52 and the third transmitting surface 51 within the second optical element 34. As a result, the third transmitting surface 51 and the fourth transmitting surface 53 are formed near the enlargement side and reduction side of the intermediate image 30. This makes it easy to correct various aberrations occurring in the enlarged image. Furthermore, the fourth transmitting surface 53 of the second optical element 34 can curve the intermediate image 30. This allows the fourth transmitting surface 53, the second relay reflecting surface 73, and the correction optical element 36 to share the function of reducing the field curvature caused by the first optical element 33.

[0066] (Other embodiments) In the optical system 3 of this example, the virtual axis V may be configured to move away from the screen S as it moves from the enlargement side to the reduction side. This allows optical elements arranged on the reduction side of the second optical element 34 to be arranged in a direction away from the enlargement-side image forming surface. This prevents optical elements arranged on the enlargement side of the second optical element 34 from interfering with the enlargement-side image forming surface. This makes it possible to install the optical system in a position close to the screen S. [Explanation of symbols]

[0067] 1...projector, 2...image forming unit, 3...optical system, 4...control unit, 6...image processing unit, 7...display driving unit, 10...light source, 11...integrator lens, 12...integrator lens, 13...polarization conversion element, 14...superimposing lens, 15...first dichroic mirror, 16...reflection mirror, 17R...field lens, 17G...field lens, 17B...field lens, 18 (18B, 18R, 18G)...liquid crystal panel, 19...cross dichroic prism, 21...second dichroic mirror, 22...relay lens, 2 3...reflecting mirror, 24...relay lens, 25...reflecting mirror, 30...intermediate image, 31...first optical system, 32...second optical system, 33...first optical element, 34...second optical element, 35...correction optical element, 37...second relay element, 38...first relay element, 41...first transmitting surface, 42...first reflecting surface, 43...second transmitting surface, 51...third transmitting surface, 52...second reflecting surface, 53...fourth transmitting surface, 71...first lens surface, 72...second lens surface, 73...second relay reflecting surface, 74...first relay reflecting surface, S...screen, V...virtual line, V1...first intersection, V2...second intersection.

Claims

1. In an optical system in which a projected image formed on a reduction-side conjugate plane is projected onto an enlargement-side conjugate plane as an enlarged image, a first optical system having a first optical element; and a second optical element disposed on the reduction side of the first optical system. Academic department and Equipped with Between the first optical system and the second optical system, the reduction-side conjugate surface and the enlargement-side conjugate surface are provided. a second optical element is disposed on which an intermediate image conjugate with the first optical element is formed and which has a second reflecting surface; the first optical element has a first reflecting surface having a concave shape; The second optical system includes a first relay element and a second relay element disposed on the magnification side of the first relay element. a correction optical element disposed on the magnification side of the first relay element, the first relay element has a first relay reflecting surface that is concave; the second relay element has a convex second relay reflecting surface; The correction optical element is a pre-generated optical element by the first relay element and the second relay element. curving the intermediate image to reduce the field curvature caused by the first optical element; The chief ray at the image height corresponding to the center of the enlarged image projected onto the enlargement-side conjugate plane is reflected by the second reflection surface. a first intersection point where the principal ray intersects with the reduction-side conjugate surface and a second intersection point where the principal ray intersects with the reduction-side conjugate surface; If a straight line is taken as a virtual axis, the virtual axis is parallel to the magnification-side conjugate plane, or As it goes from the enlargement side to the reduction side, it becomes farther from the enlargement side conjugate plane, The second optical element includes a third transmitting surface and a second reflecting surface disposed on the reduction side of the third transmitting surface. and a fourth transmitting surface disposed on the reduction side of the second reflecting surface, the third transmitting surface constitutes the first optical system, the fourth transmitting surface constitutes the second optical system, The intermediate image is formed inside the second optical element by the second reflecting surface and the third transmitting surface. formed between An optical system characterized by:

2. a light modulation element disposed on the reduction-side conjugate plane and modulating light emitted from the light source; the optical system according to claim 1 , which projects light modulated by the light modulation element; A projector comprising:

3. 3. The optical correction element according to claim 1, wherein the optical correction element is a lens made of resin. optical system.

4. 4. The optical element according to claim 3, wherein the correction optical element has aspherical shapes on both sides. system.

5. The first optical element includes a first transmitting surface and a first reflecting surface disposed on the reduction side of the first transmitting surface. and a second transmitting surface disposed on the reduction side of the first reflecting surface. Item 5. The optical system according to any one of items 1 to 4.

6. 6. The optical system according to claim 5, wherein the first transmitting surface and the second transmitting surface have aspherical shapes. The optical system according to claim 1.

Images