Projection optical system and projection type display device

Abstract

The invention provides an optical system for projection, which is compact in structure and has good optical performance, and a projection type display device provided with the optical system for projection. The projection optical system projects an image on the reduction side to the enlargement side, does not include a reflective surface having refractive power, and includes a first optical system and a second optical system in this order along an optical path from the enlargement side to the reduction side. An intermediate image is formed between the first optical system and the second optical system, and the first optical system includes an optical path deflection surface that deflects an optical path. The projection optical system satisfies 0.2 < Imax / Ddef < 0.7, where Imax is the radius of the maximum effective image circle on the reduction side, and Ddef is the distance on the optical axis from the lens surface closest to the enlargement side of the first optical system to the optical path deflection surface.

Description

Technical Field

[0001] The technology of the present invention relates to a projection optical system and a projection display device. Background Art

[0002] As an optical system applicable to a projection display device, an optical system described in Japanese Patent Document 1 listed below is known.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2014-029392

[0004] There is a demand for projection optical systems that are compact and have good optical performance, and these requirements are increasing year by year. Summary of the invention

[0005] The present invention has been made in view of the above circumstances, and provides a projection optical system which is compact and has excellent optical performance, and a projection type display device including the projection optical system.

[0006] A first aspect of the present invention is a projection optical system for projecting an image on a reduction side onto an enlargement side, wherein the projection optical system does not include a reflective surface having optical power, and includes a first optical system and a second optical system in sequence along an optical path from the enlargement side to the reduction side, an intermediate image is formed between the first optical system and the second optical system, and the first optical system includes an optical path deflection surface for deflecting the optical path, and satisfies the conditional formula (1) represented by the following formula:

[0007] 0.2<Imax / Ddef<0.7 (1).

[0008] In the present invention, the symbols of the conditional expressions are defined as follows. The radius of the maximum effective image circle on the reduction side is set to Imax. The distance on the optical axis from the lens surface closest to the magnification side to the optical path deflection surface of the first optical system is set to Ddef. In addition, when the projection optical system is a variable magnification optical system, Ddef is set to the value at the wide-angle end.

[0009] According to the second embodiment of the present invention, in the projection optical system of the first embodiment, the first optical system includes, in sequence from the magnification side to the reduction side along the optical path, a front group with negative optical focal length, an optical path deflecting component including an optical path deflecting surface, and a rear group with positive optical focal length.

[0010] A third aspect of the present invention is the projection optical system of the second aspect, wherein the front group includes one or more positive lenses.

[0011] According to a fourth aspect of the present invention, in the projection optical system of the second aspect, the outermost periphery of the optically effective surface closest to the magnification side of the first optical system is located closer to the reduction side than the intersection of the optically effective surface and the optical axis in the optical axis direction.

[0012] According to a fifth aspect of the present invention, in the projection optical system of the third aspect, when the average value of the Abbe numbers of all negative lenses included in the front group on the d-line basis is set to νnave, and the average value of the Abbe numbers of all positive lenses included in the front group on the d-line basis is set to νpave, the projection optical system satisfies the conditional formula (2) represented by the following formula:

[0013] 10<v nave-v pave<40 (2).

[0014] According to a sixth aspect of the present invention, in the projection optical system of the third aspect, when the average value of the refractive indexes of all the negative lenses included in the front group with respect to the d-line is set to Nnave, and the average value of the refractive indexes of all the positive lenses included in the front group with respect to the d-line is set to Npave, the projection optical system satisfies the conditional formula (3) represented by the following formula:

[0015] 0.15<Npave-Nnave<0.45 (3).

[0016] According to a seventh aspect of the present invention, in the projection optical system of the second aspect, at least a part of the rear group moves during focusing.

[0017] According to an eighth aspect of the present invention, in the projection optical system of the first aspect, the second optical system includes two or more moving groups that move along the optical axis during magnification change.

[0018] A ninth aspect of the present invention is the projection optical system of the eighth aspect, wherein the moving group closest to the magnification side among the moving groups of the second optical system has positive refractive power.

[0019] According to a tenth aspect of the present invention, in the projection optical system of the second aspect, when the air conversion distance on the optical axis from the surface closest to the reduction side of the front group to the surface closest to the magnification side of the rear group is set to Dfr, and when the projection optical system is a variable power optical system, Dfr is set to a value at the wide-angle end, the projection optical system satisfies the conditional formula (4) represented by the following formula:

[0020] 0.5 <Imax / Dfr<0.9(4)。

[0021] According to an eleventh aspect of the present invention, in the projection optical system of the second aspect, the optical path deflecting surface is a surface of a prism.

[0022] According to a twelfth aspect of the present invention, in the projection optical system of the eleventh aspect, when the thickness of the prism along the optical axis is set to Dpr and the refractive index of the prism with respect to the d-line is set to Npr, the projection optical system satisfies the conditional formula (5) represented by the following formula:

[0023] 0.9 <Imax / (Dpr / Npr)<1.3 (5)。

[0024] According to a thirteenth aspect of the present invention, in the projection optical system of the first aspect, when the maximum effective radius of the lens surface of the first optical system closest to the magnification side is set to ERf and the maximum value of the maximum effective radius of all lens surfaces of the projection optical system is set to ERmax, the projection optical system satisfies the conditional formula (6) represented by the following formula:

[0025] 0 <ERf / ERmax<0.7 (6)。

[0026] According to a 14th aspect of the present invention, in the projection optical system of the 1st aspect, when the maximum value of the height of the on-axis marginal light rays on all lens surfaces of the first optical system from the optical axis is set to AH1, and the maximum value of the height of the on-axis marginal light rays on all lens surfaces of the second optical system from the optical axis is set to AH2, the projection optical system satisfies the conditional formula (7) represented by the following formula:

[0027] 0 <AH1 / AH2<0.7 (7)。

[0028] According to the fifteenth mode of the present invention, in the projection optical system of the first mode, an aperture stop is included at a position closer to the reduction side than the intermediate image, a real image of the aperture stop exists inside the first optical system, and when the position of the real image of the aperture stop in the optical axis direction is set as the first position, and the position farthest from the first position among the positions where light emitted from any point within the maximum effective image circle on the reduction side and passing through the center of the aperture stop toward the magnification side intersects the optical axis at a position closer to the magnification side than the intermediate image is set as the second position, the intersection of the light path deflection surface and the optical axis is located in the range from the first position to the second position in the optical axis direction.

[0029] The 16th aspect of the present invention is that in the projection optical system of the 15th aspect, when a natural number from 1 to 10 is set as k, a point on the maximum effective image circle on the reduction side whose height from the optical axis is k tenths of the radius of the maximum effective image circle is set as point PHk, a position where a light ray emitted from point PHk and passing through the center of the aperture stop toward the magnification side intersects the optical axis at a position closer to the magnification side than the intermediate image is set as position Pk, a position on the optical axis with the longest air-converted distance from the first position in position Pk is set as the third position, an air-converted distance from the first position to the third position is set as DifP, in the sign of DifP, the distance on the reduction side is set as positive and the distance on the magnification side is set as negative with the first position as a reference, and when the projection optical system is a variable-power optical system, DifP is set as a value at the wide-angle end, the projection optical system satisfies the conditional formula (8) represented by the following formula:

[0030] -3 <DifP / Imax<-0.2 (8)。

[0031] According to a 17th aspect of the present invention, in the projection optical system of the 16th aspect, the first optical system includes a front group, an optical path deflecting component including an optical path deflecting surface, and a rear group in order from the magnification side to the reduction side along the optical path, and when the air conversion distance on the optical axis from the surface of the front group closest to the reduction side to the surface of the rear group closest to the magnification side is set to Dfr, and when the projection optical system is a variable magnification optical system, Dfr is set to a value at the wide-angle end, the projection optical system satisfies the conditional formula (9) represented by the following formula:

[0032] 0.4<DifP / Dfr<0.7 (9).

[0033] According to an eighteenth aspect of the present invention, in the projection optical system of the sixteenth aspect, the optical path deflecting surface is a surface of a prism.

[0034] According to a 19th aspect of the present invention, in the projection optical system according to the 18th aspect, when the thickness of the prism along the optical axis is set to Dpr and the refractive index of the prism with respect to the d-line is set to Npr, the projection optical system satisfies the conditional equation (10) represented by the following equation:

[0035] 0.7<DifP / (Dpr / Npr)<1.8(10).

[0036] A twentieth aspect of the present invention is a projection display device comprising the projection optical system according to any one of the first to nineteenth aspects.

[0037] In addition, the terms "including..." and "including..." in this specification mean that, in addition to the listed constituent elements, the following may also be included: lenses that essentially have no optical focal length (refractive power), and optical elements other than lenses such as apertures, masks, filters, cover glasses, plane mirrors and prisms, as well as mechanical parts such as lens flanges, lens barrels, camera elements and hand-shake correction mechanisms.

[0038] In this specification, "a group having positive power" and "a group having positive power" mean that the group as a whole has positive power. Similarly, "a group having negative power" and "a group having negative power" mean that the group as a whole has negative power. In this specification, "front group", "rear group", "focusing group", and "lens group" are not limited to structures including multiple lenses, but may also be structures including only one lens.

[0039] A composite aspheric lens (a lens (e.g., a spherical lens) and a film having an aspheric shape formed on the lens are integrated and function as a single aspheric lens as a whole) is used as a single lens and is not considered a cemented lens. Unless otherwise specified, the sign of the optical power and the surface shape associated with the lens including an aspheric surface use the sign of the optical power and the surface shape of the paraxial region. Unless otherwise specified, the "distance on the optical axis" used in the conditional expression is a geometric distance. The "focal length" used in the conditional expression is the paraxial focal length. The values ​​used in the conditional expression are values ​​based on the d-line.

[0040] The "d line", "C line", and "F line" described in this specification are clear lines, and the wavelength of the d line is considered to be 587.56 nm (nanometers), the wavelength of the C line is considered to be 656.27 nm (nanometers), and the wavelength of the F line is considered to be 486.13 nm (nanometers).

[0041] Effects of the Invention

[0042] According to the present invention, it is possible to provide a projection optical system that is compact and has excellent optical performance, and a projection type display device including the projection optical system. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 Corresponding to the projection optical system of Example 1, this is a cross-sectional view showing the structure and light flux of the projection optical system according to one embodiment.

[0044] Figure 2 yes Figure 1 A partial enlarged view of the optical system for projection.

[0045] Figure 3 It means expansion Figure 1 A cross-sectional view of the structure of the optical path and the luminous flux of the projection optical system.

[0046] Figure 4 It is a diagram for explaining the maximum effective radius.

[0047] Figure 5 It means in Figure 1 A diagram of light rays that originate from a point within the maximum effective image circle on the reduction side and pass through the center of the aperture stop toward the magnification side in a projection optical system.

[0048] Figure 6 yes Figure 5 An enlarged view of the main part.

[0049] Figure 7 It means in Figure 1 A diagram of light that originates from point PHk on the reduction side and passes through the center of the aperture stop toward the magnification side in a projection optical system.

[0050] Figure 8 yes Figure 7 An enlarged view of the main part.

[0051] Fig. 9 1 and 2 are diagrams showing various aberrations of the projection optical system of Example 1.

[0052] Fig.10 It is a cross-sectional view showing the structure and luminous flux of the projection optical system of Example 2.

[0053] Fig.11 It means expansion Fig.10 A cross-sectional view of the structure of the optical path and the luminous flux of the projection optical system.

[0054] Fig.12 1 and 2 are diagrams showing various aberrations of the projection optical system of Example 2.

[0055] Fig.13 It is a cross-sectional view showing the structure and luminous flux of the projection optical system of Example 3.

[0056] Fig.14 It means expansion Fig.13 A cross-sectional view of the structure of the optical path and the luminous flux of the projection optical system.

[0057] Fig.15 1 and 2 are diagrams showing various aberrations of the projection optical system of Example 3.

[0058] Fig.16 It is a cross-sectional view showing the structure and luminous flux of the projection optical system of Example 4.

[0059] Fig.17 It means expansion Fig.16 A cross-sectional view of the structure of the optical path and the luminous flux of the projection optical system.

[0060] Fig.18 These are various aberration diagrams of the projection optical system of Example 4.

[0061] Fig.19 It is a schematic structural diagram of a projection display device according to one embodiment.

[0062] Fig. 20 It is a schematic structural diagram of a projection display device according to another embodiment.

[0063] Fig.21 It is a schematic structural diagram of a projection display device according to still another embodiment.

[0064] Fig. 22 It is a schematic structural diagram of a projection display device according to still another embodiment.

[0065] Explanation of symbols

[0066] 2-point, 4-intersection, 10-optical system for projection, 11a~11c-transmissive display element, 12-dichroic mirror, 13-dichroic mirror, 14-cross-dichroic prism, 15-light source, 16a~16c-condensing lens, 18a~18c-total reflection mirror, 21a~21c-DMD element, 24a~24c-TIR prism, 25-polarization beam splitter prism, 31a~31c-reflective display element, 32-dichroic mirror, 33-dichroic mirror, 34-cross-dichroic prism, 35a~35c-polarization Beam splitter, 38-total reflection mirror, 61-light source, 62-color wheel, 63-light guide optical system, 64-DMD element, 65-TIR prism, 66-optical system for projection, 67-screen, 100-projection display device, 105-screen, 200-projection display device, 205-screen, 210-optical system for projection, 215-light source, 300-projection display device, 305-screen, 310-optical system for projection, 315-light source, 600-projection display device, AH1 - maximum value, AH2 - maximum value, B0 - axial luminous flux, BOM - axial marginal ray, B1 - luminous flux at maximum viewing angle, B2 - luminous flux at maximum viewing angle, Ddef - distance, Dpr - thickness, ER - maximum effective radius, G1 - 1st optical system, G1F - front group, G1R - rear group, G2 - 2nd optical system, G2A - 2A lens group, G2B - 2B lens group, G2C - 2C lens group, G2D - 2D lens group, G2E - 2E lens group, G2F - 2F lens Group, Imax-radius L1a~L2n-lens, Lx-lens, MI-intermediate image, Mr-plane mirror, PH1-point, PH10-point, PP-optical component, Pch-position, Pdef-position, Pist-position, Pmax-position, Pr-prism, Prs-reflecting surface, Px-position, Ry1-light, Ry10-light, Rys-light, Sim-display surface, St-aperture stop, Xa-light flux on the axis, Xb-light flux outside the axis, Xb1-light, Z-optical axis. DETAILED DESCRIPTION

[0067] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0068] Figure 1 , a cross-sectional view showing the structure and light flux of a projection optical system according to an embodiment of the present invention is shown. Figure 1 In FIG. 1 , as luminous flux, the axial luminous flux B0 and the luminous fluxes B1 and B2 at the maximum viewing angle are shown. Figure 1 The example shown corresponds to the projection optical system of Example 1 described later. Figure 1In the figure, the upper left side is the enlarged side, and the lower right side is the reduced side.

[0069] exist Figure 1 In the figure, an example is shown in which an optical system for projection is assumed to be mounted in a projection-type display device, and an optical component PP and a display surface Sim of a light valve are arranged on the reduction side of the optical system for projection. The light valve is a display element that outputs an optical image, and the optical image is displayed on the display surface Sim in the form of an image. As the light valve, for example, an image display element such as a liquid crystal display element or a DMD (digital micromirror device: registered trademark) can be used. The optical component PP is a component that is assumed to be a filter, a cover glass, and a color synthesis prism. The optical component PP is a component that does not have optical power. The material, length, and number of components of the optical component PP can be appropriately changed, and it can also be a structure in which the optical component PP is omitted.

[0070] The projection optical system is, for example, mounted on a projection-type display device, and enlarges and projects the image displayed on the display surface Sim of the display element on the reduction side onto the projection surface on the magnification side. In a projection-type display device, the luminous flux imparted with image information on the display surface Sim is incident on the projection optical system via the optical component PP, and is projected onto a screen (not shown) serving as a projection surface by the projection optical system. That is, the display surface Sim and the screen are located at optically conjugate positions. The display surface Sim corresponds to the conjugate surface on the reduction side, and the screen corresponds to the conjugate surface on the magnification side. In addition, in this specification, the "screen" refers to the object on which the projection image formed by the projection optical system is projected. As a screen, in addition to a dedicated screen, it can also be a wall surface, a floor surface, a ceiling, and an outer wall of a building in a room.

[0071] In the description of this specification, "magnification side" refers to the screen side on the optical path, and "reduction side" refers to the display surface Sim side on the optical path. In this specification, "magnification side" and "reduction side" are determined along the optical path. And, "adjacent" related to the configuration of the constituent elements means adjacent as the arrangement order on the optical path. In the following, in order to avoid the description becoming redundant, "from the magnification side to the reduction side along the optical path in sequence" is sometimes recorded as "from the magnification side to the reduction side in sequence".

[0072] The projection optical system of the present invention is configured to not include a reflective surface with optical power. In the projection optical system, a structure is sometimes adopted to displace the center position of the image of the display surface Sim from the optical axis Z of the projection optical system in a direction perpendicular to the optical axis Z. In the projection optical system including a reflective surface with optical power such as a concave mirror, there is an area near the optical axis Z in the image circle that is blocked by the projection type display device and cannot be used, so the displacement is mostly fixed. In contrast, in the projection optical system that does not include a reflective surface with optical power as in the present invention, there is no problem of blocking as described above, and the displacement can be changed within the image circle, so it can be set to a structure with a high degree of freedom.

[0073] The projection optical system of the present invention includes a first optical system G1 and a second optical system G2 in order along the optical path from the magnification side to the reduction side, and an intermediate image MI is formed between the first optical system G1 and the second optical system G2. In the case of shortening the focal length of the projection optical system to implement wide angle, if the required optical performance is achieved while ensuring the back focal length required in the projection optical system, the lens on the magnification side tends to become huge. By setting it as a relay optical system in which the intermediate image MI is formed, the back focal length of the optical system closer to the magnification side than the intermediate image MI can be shortened, and the diameter of the lens on the magnification side can be reduced, which is conducive to miniaturization.

[0074] The first optical system G1 is configured to include an optical path deflecting surface that deflects the optical path. By deflecting the optical path, the optical system can be configured compactly, which is advantageous for miniaturization.

[0075] As an example, Figure 1 The projection optical system is constructed as follows. The first optical system G1 includes a front group G1F, a prism Pr, and a rear group G1R in order from the magnification side to the reduction side. The front group G1F includes lenses L1a to L1d in order from the magnification side to the reduction side. The rear group G1R includes lenses L1e to L1n in order from the magnification side to the reduction side. The second optical system G2 includes lens L2a, a plane mirror Mr, lenses L2b to L2h, an aperture stop St, and lenses L2i to L2m in order from the magnification side to the reduction side along the optical path. In addition, Figure 1 The aperture stop St shown does not indicate the size or shape, but indicates the position in the optical axis direction. The same method of illustrating the aperture stop St is also used in other drawings. Figure 1 In FIG. 1 , the intermediate image MI is conceptually shown by a dotted line. Figure 1 The shape of the middle like MI is not accurate.

[0076] exist Figure 2 Shown in Figure 1 An enlarged view of the prism Pr and the lenses near it in the projection optical system. Figure 2In the figure, the luminous flux only represents the axial luminous flux B0. The prism Pr includes a reflecting surface Prs inside. The reflecting surface Prs is an example of a light path deflecting surface for deflecting the light path of the present invention. The prism Pr is an example of a light path deflecting component of the present invention. By setting the light path deflecting surface as the surface of the prism Pr, it is helpful to ensure the performance during assembly. In addition, the surface of the prism formed with a reflective film can be used as the light path deflecting surface, and the surface of the prism can also be used as the light path deflecting surface by using total reflection.

[0077] The outermost periphery of the optically effective surface closest to the magnification side of the first optical system G1 is preferably located closer to the reduction side in the optical axis direction than the intersection of the optically effective surface and the optical axis Z. This is advantageous in correcting distortion.

[0078] exist Figure 1 In the projection optical system of , the optically effective surface of the first optical system G1 closest to the magnification side is located on the surface of the lens L1a on the magnification side. Figure 2 , a point 2 on the outermost periphery of the optically effective surface of the first optical system G1 closest to the magnification side and an intersection 4 of the optically effective surface and the optical axis Z are shown. Figure 2 As shown, in the optical axis direction, point 2 is located closer to the reduction side than intersection point 4.

[0079] In addition, the "optically effective surface" is usually a mirror-finished surface. In this specification, the "optically effective surface" of a lens is a surface that includes the surface within the effective diameter through which the imaging light passes, and extends radially outward in the same shape as the surface shape within the effective diameter. The same shape refers to a surface having a shape formed according to the same design data. "The same design data" means that when the shape is a spherical surface, the radius of curvature is the same, when the shape is an aspherical surface, the aspherical type and aspherical coefficient are the same, and when the shape is a free-form surface, the free-form surface type and free-form surface coefficient are the same.

[0080] Preferably, the optical power of the front group G1F is negative, and the optical power of the rear group G1R is positive. By configuring the first optical system G1 to include the front group G1F with negative optical power, the optical path deflection component, and the rear group G1R with positive optical power in order from the magnification side to the reduction side, it is advantageous to achieve miniaturization while ensuring a wide angle.

[0081] The front group G1F preferably includes one or more positive lenses, which is advantageous for correcting chromatic aberration and field curvature.

[0082] At least a portion of the rear group G1R preferably moves along the optical axis Z during focusing. With this structure, a projection optical system with a focusing function can be formed. In addition, in such a case, the front group G1F is fixed during focusing, and a structure without a focusing mechanism can be provided in the front group G1F, which is conducive to miniaturization of the lens closest to the magnification side. Hereinafter, the group that moves during focusing is referred to as the focusing group. The focusing group performs focusing by moving along the optical axis Z.

[0083] exist Figure 1 In the example of FIG. 1 , the focus group includes lenses L1g to L11. Figure 1 and Figure 3 The brackets and double arrows around the lenses L1g to L1l indicate that the lenses L1g to L1l form a focusing group. Figure 3 Yes Expand Figure 1 A cross-sectional view of the optical path of the projection optical system. Figure 3 In the figure, the reflecting surface Prs, the plane mirror Mr, and the luminous flux B2 at the maximum viewing angle are omitted.

[0084] The second optical system G2 preferably includes two or more moving groups that move along the optical axis Z when changing the magnification. With this structure, a projection optical system with a variable magnification function can be formed. In addition, by configuring the moving group on the second optical system G2 with a small diameter, the load of the variable magnification mechanism can be reduced. In addition, the variable magnification optical system can be formed within the range of the refractive optical system that does not include the deflection optical path, so it is easy to ensure mechanical accuracy.

[0085] The moving group closest to the magnification side among the moving groups of the second optical system G2 preferably has a positive optical focal length. In this case, it is more advantageous to reduce the diameter of the moving group on the reduction side than the moving group closest to the magnification side. Furthermore, it is easy to ensure a long air gap that is closer to the reduction side than the intermediate image MI and closer to the magnification side than the moving group closest to the magnification side. If a component that deflects the optical path is disposed in the long air gap, the optical path can be deflected more than twice in the entire projection optical system, which is more advantageous for miniaturization. Figure 1 In the second optical system G2, the optical path is deflected by 90 degrees by the plane mirror Mr arranged in the long air gap.

[0086] The second optical system G2 preferably includes one positive lens on the most reduced side and includes a fixed group fixed to the display surface Sim during zooming. In this case, it is easy to ensure telecentricity on the reduced side.

[0087] As an example, Figure 3 As shown, Figure 1The second optical system G2 includes five lens groups, namely, a 2A lens group G2A, a 2B lens group G2B, a 2C lens group G2C, a 2D lens group G2D, and a 2E lens group G2E, in order from the magnification side to the reduction side. Figure 3 The lens groups are constructed as follows. The 2A lens group G2A includes lens L2a. The 2B lens group G2B includes lenses L2b~L2e. The 2C lens group G2C includes lenses L2f~L2h, an aperture stop St, and a lens L2i. The 2D lens group G2D includes lenses L2j~L21. The 2E lens group G2E includes lens L2m. When changing the magnification, the 2A lens group G2A and the 2E lens group G2E are fixed on the display surface Sim, and the 2B lens group G2B, the 2C lens group G2C and the 2D lens group G2D change the interval with the adjacent lens groups and move along the optical axis Z. Figure 3 In the figure, brackets and arrows indicating the approximate movement direction of each lens group when zooming from the wide-angle end to the telephoto end are written below the lens group that moves when zooming.

[0088] Next, the preferred structure and possible structure related to the conditional formula of the projection optical system of the present invention are described. In the description related to the following conditional formula, in order to avoid redundant description, the same symbols are used for the parts with the same definition, thereby omitting the repeated description of the symbols. And, in order to avoid redundant description, the "projection optical system of the present invention" is also referred to as "projection optical system" for short.

[0089] The projection optical system preferably satisfies the following conditional expression (1). Here, the radius of the maximum effective image circle on the reduction side is set to Imax. The distance on the optical axis from the lens surface closest to the magnification side to the light path deflection surface of the first optical system G1 is set to Ddef. Imax is the maximum image height on the reduction side. As an example, Figure 1 The above-mentioned radius Imax and distance Ddef are shown in FIG. In addition, when the projection optical system is a variable magnification optical system, Ddef is set to the value at the wide-angle end. By making the corresponding value of conditional expression (1) not reach below the lower limit value, the enlargement of the lens closest to the magnification side can be suppressed. By making the corresponding value of conditional expression (1) not reach above the upper limit value, it is beneficial to maintain good optical performance and specifications.

[0090] 0.2 <Imax / Ddef<0.7 (1)

[0091] In order to obtain better characteristics, the lower limit value of the conditional expression (1) is more preferably 0.25, and further preferably 0.3. In order to obtain better characteristics, the upper limit value of the conditional expression (1) is more preferably 0.6, and further preferably 0.5.

[0092] The projection optical system preferably satisfies the following conditional expression (2). Here, the average value of the Abbe numbers of the d-line reference of all negative lenses included in the front group G1F is set to ν nave. The average value of the Abbe numbers of the d-line reference of all positive lenses included in the front group G1F is set to ν pave. By making the corresponding value of the conditional expression (2) not reach below the lower limit value, it is beneficial to correct chromatic aberration. By making the corresponding value of the conditional expression (2) not reach above the upper limit value, it is beneficial to correct the secondary spectrum of chromatic aberration.

[0093] 10 <V nave-v pave<40 (2)

[0094] In order to obtain better characteristics, the lower limit value of conditional expression (2) is more preferably set to 12, and further preferably set to 15. In order to obtain better characteristics, the upper limit value of conditional expression (2) is more preferably set to 36, and further preferably set to 32.

[0095] The projection optical system preferably satisfies the following conditional formula (3). Here, the average value of the refractive index of all negative lenses included in the front group G1F with respect to the d-line is set to Nnave. The average value of the refractive index of all positive lenses included in the front group G1F with respect to the d-line is set to Npave. By making the corresponding value of the conditional formula (3) not reach below the lower limit value, it is beneficial to correct the image plane curvature. By making the corresponding value of the conditional formula (3) not reach above the upper limit value, it is beneficial to correct the spherical aberration.

[0096] 0.15 <Npave-Nnave<0.45 (3)

[0097] In order to obtain better characteristics, the lower limit value of conditional expression (3) is more preferably 0.18, and more preferably 0.2. In order to obtain better characteristics, the upper limit value of conditional expression (3) is more preferably 0.36, and more preferably 0.3.

[0098] The projection optical system preferably satisfies the following conditional expression (4). Here, the air-converted distance on the optical axis from the surface of the front group G1F closest to the reduction side to the surface of the rear group G1R closest to the magnification side is set to Dfr. In addition, when the projection optical system is a variable-power optical system, Dfr is set to the value at the wide-angle end. Conditional expression (4) is a formula that specifies the ratio of the maximum image height on the reduction side to the space in which the optical path deflection component is configured. By conditional expression (4), the diameter of the luminous flux in the optical path deflection component can be suppressed. By making the corresponding value of conditional expression (4) not reach below the lower limit value, the enlargement of the lens closest to the magnification side can be suppressed. By making the corresponding value of conditional expression (4) not reach above the upper limit value, the space through which the luminous flux deflected by the optical path passes can be ensured.

[0099] 0.5 <Imax / Dfr<0.9 (4)

[0100] In order to obtain better characteristics, the lower limit value of the conditional expression (4) is more preferably set to 0.6. In order to obtain better characteristics, the upper limit value of the conditional expression (4) is more preferably set to 0.8.

[0101] The projection optical system preferably satisfies the following conditional expression (5). Here, the thickness of the prism Pr along the optical axis Z is set to Dpr. The refractive index of the prism Pr with respect to the d-line is set to Npr. As an example, Figure 3 The thickness Dpr is shown in FIG. Conditional expression (5) is a formula that specifies the ratio of the maximum image height on the reduction side to the thickness of the prism Pr converted to air. By making the corresponding value of conditional expression (5) not below the lower limit, the enlargement of the lens closest to the magnification side can be suppressed. By making the corresponding value of conditional expression (5) not above the upper limit, the space through which the light flux that deflects the optical path passes can be ensured.

[0102] 0.9 <Imax / (Dpt / Npr)<1.3 (5)

[0103] In order to obtain better characteristics, the lower limit value of the conditional expression (5) is more preferably set to 1. In order to obtain better characteristics, the upper limit value of the conditional expression (5) is more preferably set to 1.2.

[0104] The projection optical system preferably satisfies the following conditional expression (6). Here, the maximum effective radius of the lens surface closest to the magnification side of the first optical system G1 is set to ERf. The maximum value of the maximum effective radius of all lens surfaces of the projection optical system is set to ERmax. Regarding the lower limit value of the conditional expression (6), since ERf>0 and ERmax>0, it becomes ERf / ERmax>0. By making the corresponding value of the conditional expression (6) not reach the upper limit value, it is possible to suppress the enlargement of the lens closest to the magnification side, or it is beneficial to correct the off-axis aberration.

[0105] 0 <ERf / ERmax<0.7 (6)

[0106] In order to obtain better characteristics, the upper limit value of conditional expression (6) is more preferably set to 0.6.

[0107] refer to Figure 4 , the maximum effective radius is explained. Figure 4 is a diagram for illustration. Figure 4 In the , the left side is the magnified side, and the right side is the reduced side. Figure 4 The axial luminous flux Xa and the off-axis luminous flux Xb passing through the lens Lx are shown in FIG. Figure 4In the example, the light ray Xb1, which is the upper light ray of the off-axis light flux Xb, is the light ray that passes through the outermost side. The "outer side" mentioned here refers to the radial outer side with the optical axis Z as the center, that is, the side away from the optical axis Z. In this specification, the distance from the position Px of the intersection of the light ray passing through the outermost side and the lens surface to the optical axis Z is the maximum effective radius ER of the lens surface. Figure 4 In the example of , the upper ray of the off-axis light flux Xb is the ray that passes closest to the outside, but which ray becomes the ray that passes closest to the outside varies depending on the optical system.

[0108] In the case where condition (6) is satisfied Figure 3 In the example, the diameter of the lens closest to the magnification side is smaller than the diameter of the lens in the middle of the projection optical system. Generally, in the projection optical system, the diameter of the lens closest to the magnification side is often larger, but in Figure 3 In the example of FIG. 1 , the diameter of the lens closest to the magnification side is appropriately reduced.

[0109] The projection optical system preferably satisfies the following conditional expression (7). Here, the maximum value of the height of the on-axis marginal light ray B0m from the optical axis Z on all lens surfaces of the first optical system G1 is set to AH1. The maximum value of the height of the on-axis marginal light ray B0m from the optical axis Z on all lens surfaces of the second optical system G2 is set to AH2. As an example, in Figure 1 In the projection optical system, the height of the on-axis marginal ray B0m from the optical axis Z on the surface of the lens L1f on the magnification side is AH1, and the height of the on-axis marginal ray B0m from the optical axis Z on the surface of the lens L2c on the reduction side is AH2. Figure 2 The maximum value AH1 is shown in Figure 3 The maximum value AH2 mentioned above is shown in . In addition, when the projection optical system is a variable magnification optical system, AH1 and AH2 are the maximum values ​​in the entire variable magnification area. Regarding the lower limit value of conditional expression (7), since AH1>0 and AH2>0, it becomes AH1 / AH2>0. By making the corresponding value of conditional expression (7) not reach the upper limit value, the expansion of the luminous flux width near the optical path deflection surface can be suppressed, so that the enlargement of the lens closest to the magnification side can be suppressed.

[0110] 0 <AH1 / AH2<0.7 (7)

[0111] Next, refer to Figure 5 and Figure 6 The preferred position for configuring the light path deflection surface is described below. Figure 5 , a diagram showing the light path being expanded so as to form a straight light path. Figure 6An enlarged view of the prism Pr portion is shown in FIG. 1 . When the projection optical system includes an aperture stop St on the reduction side closer to the intermediate image MI, and the real image of the aperture stop St exists inside the first optical system G1, the position of the optical path deflection surface is preferably set as follows. Here, the position of the real image of the aperture stop St in the optical axis direction is set as position Pist. The position farthest from position Pist among the positions where a light ray emitted from any point within the maximum effective image circle on the reduction side and passing through the center of the aperture stop St toward the magnification side intersects with the optical axis Z closer to the magnification side than the intermediate image MI is set as position Pch. The intersection of the optical path deflection surface and the optical axis Z is preferably located in the range from position Pist to position Pch in the optical axis direction. In such a case, the optical path deflection surface can be arranged near the real image of the pupil. In addition, when the projection optical system is a variable magnification optical system, at the wide-angle end, the intersection of the optical path deflection surface and the optical axis Z is preferably located in the above-mentioned range.

[0112] As an example, in Figure 5 and Figure 6 In the figure, double-dotted lines are used to indicate Figure 1 The projection position Pi st in the optical system is represented by a short dashed line, the position Pch is represented by a long dashed line, and the position Pdef of the intersection of the light path deflection surface and the optical axis Z is represented by a long dashed line. Figure 5 and Figure 6 In the figure, these positions in the direction of the optical axis are shown. Figure 5 and Figure 6 In FIG. 1 , a plurality of light rays Rys are also shown, which are emitted from a plurality of points within the maximum effective image circle on the reduction side and pass through the center of the aperture stop St toward the magnification side. Figure 1 In the projection optical system, the above three positions are all located inside the prism Pr which serves as the light path deflecting component.

[0113] With regard to the above-mentioned position Pist, the projection optical system preferably satisfies the following conditional expression (8). Figure 7 and Figure 8 Conditional formula (8) is explained below. Figure 7 In FIG. 1 , a diagram showing the light path being expanded so as to form a straight light path is shown. Figure 8, an enlarged view of the prism Pr portion is shown. Here, a natural number from 1 to 10 is set as k. That is, k=1, 2, 3, 4, 5, 6, 7, 8, 9, 10. In addition, a point on the maximum effective image circle on the reduction side whose height from the optical axis Z is k tenths of the radius Imax of the maximum effective image circle is set as point PHk. The position where the light emitted from point PHk and passed through the center of the opening aperture St toward the magnification side intersects with the optical axis Z closer to the magnification side than the intermediate image MI is set as position Pk. The position in position Pk where the air-converted distance from position Pist is the longest is set as position Pmax. In addition, the air-converted distance on the optical axis from position Pist to position Pmax is set as DifP. The sign of DifP is based on position Pist, and the distance on the reduction side is set as positive, and the distance on the magnification side is set as negative. In addition, when the projection optical system is a variable magnification optical system, DifP is set to the value at the wide-angle end. It can be said that conditional expression (8) is a formula that specifies the ratio of pupil aberration to maximum image height. By making the corresponding value of conditional expression (8) not below the lower limit value, the total length of the optical system can be suppressed from being increased. By making the corresponding value of conditional expression (8) not above the upper limit value, the enlargement of the lens closest to the magnification side can be suppressed.

[0114] -3<DifP / Imax<-0.2 (8)

[0115] In order to obtain better characteristics, the lower limit value of the conditional expression (8) is more preferably set to -2.5. In order to obtain better characteristics, the upper limit value of the conditional expression (8) is more preferably set to -0.5.

[0116] As an example, in Figure 7 and Figure 8 In the figure, double-dotted lines are used to indicate Figure 1 The position Pist in the projection optical system is indicated by the dotted line, and the position Pmax is indicated by the dotted line. Figure 7 and Figure 8 In the figure, these positions in the direction of the optical axis are shown. Figure 7 and Figure 8 In FIG. 1 , 10 light rays Ry1, ..., Ry10 are shown which are emitted from a point PHk on the maximum effective image circle on the reduction side and whose height from the optical axis Z is k tenths of the radius Imax of the maximum effective image circle and pass through the center of the aperture stop St toward the magnification side. In addition, in order to avoid complicating the figure, Figure 7 In , only points PH1 and PH10 in PHk are marked with symbols. Figure 1 In the projection optical system, position Pist and position Pmax are located inside the prism Pr which serves as a light path deflecting component.

[0117] Furthermore, regarding the above-mentioned DifP, the projection optical system preferably satisfies the following conditional formula (9). It can be said that conditional formula (9) is a formula that specifies the ratio of pupil aberration to the space in which the optical path deflection component is configured. By conditional formula (9), the diameter of the luminous flux in the optical path deflection component can be suppressed. By making the corresponding value of conditional formula (9) not reach below the lower limit value, the enlargement of the lens closest to the magnification side can be suppressed. By making the corresponding value of conditional formula (9) not reach above the upper limit value, the space through which the luminous flux deflected by the optical path passes can be ensured.

[0118] 0.4<DifP / Dfr<0.7 (9)

[0119] In order to obtain better characteristics, the lower limit value of the conditional expression (9) is more preferably set to 0.45. In order to obtain better characteristics, the upper limit value of the conditional expression (9) is more preferably set to 0.6.

[0120] The projection optical system preferably satisfies the following conditional formula (10). It can be said that conditional formula (10) is a formula that specifies the ratio of pupil aberration to the thickness of the prism Pr converted to air. By making the corresponding value of conditional formula (10) not reach below the lower limit value, the enlargement of the lens closest to the magnification side can be suppressed. By making the corresponding value of conditional formula (10) not reach above the upper limit value, the space through which the luminous flux that deflects the optical path passes can be ensured.

[0121] 0.7<DifP / (Dpr / Npr)<1.8(10)

[0122] In order to obtain better characteristics, the lower limit value of the conditional expression (10) is more preferably set to 0.75. In order to obtain better characteristics, the upper limit value of the conditional expression (10) is more preferably set to 1.2.

[0123] in addition, Figure 1 The example shown is only an example, and various modifications can be made without departing from the technical spirit of the present invention. For example, the number of lenses included in each optical system and the shape of the lenses can also be different. Figure 1 The example is different. Figure 1 In the example, the optical elements having optical power are all refractive elements, but the projection optical system of the present invention may also include diffractive optical elements.

[0124] The light path deflection surface may also be the surface of a reflector. In this case, it is beneficial to weight reduction. The reflector may be a metal mirror or a dielectric multilayer mirror. Furthermore, the number of light path deflection surfaces included in the projection optical system can be set arbitrarily. If the angle at which the light path deflection surface deflects the light path is 90 degrees, it is beneficial to manufacturing, but it may also be an angle other than 90 degrees. In addition, the above-mentioned "90 degrees" includes the error actually allowed in the technical field to which the technology of the present invention belongs. Regarding the error, for example, it can be set within a range of more than -1 degree and less than +1 degree.

[0125] The above-mentioned preferred structures and possible structures including structures related to conditional expressions can be arbitrarily combined, and are preferably appropriately and selectively adopted according to required specifications.

[0126] As an example, a preferred embodiment of the present invention is a projection optical system that projects an image on the reduction side onto the magnification side, wherein the projection optical system does not include a reflective surface with optical focal length, and includes a first optical system G1 and a second optical system G2 in sequence along the optical path from the magnification side to the reduction side, an intermediate image MI is formed between the first optical system G1 and the second optical system G2, the first optical system G1 includes an optical path deflection surface for deflecting the optical path, and the projection optical system satisfies the above-mentioned conditional expression (1).

[0127] Next, embodiments of the projection optical system of the present invention are described with reference to the accompanying drawings. In addition, the reference symbols marked on the cross-sectional views of each embodiment are used independently in each embodiment to avoid the complication of the description and the accompanying drawings caused by the increase in the number of digits of the reference symbols. Therefore, even if the same reference symbols are marked in the accompanying drawings of different embodiments, they are not necessarily the same structures.

[0128] [Example 1]

[0129] The structure of the projection optical system and the cross-sectional view of the light flux of Example 1 are shown in Figure 1 , its diagrammatic method and structure are as described above, so some repeated descriptions are omitted here. The projection optical system of Example 1 includes the first optical system G1 and the second optical system G2 in sequence along the optical path from the magnification side to the reduction side, and an intermediate image MI is formed between the first optical system G1 and the second optical system G2. The first optical system G1 includes a prism Pr inside. The prism Pr has a reflecting surface Prs, and the reflecting surface Prs functions as an optical path deflecting surface that deflects the optical path by 90 degrees. The second optical system G2 includes 5 lens groups, of which 3 lens groups change the interval with the adjacent lens groups and move when changing the magnification. The second optical system G2 includes a plane mirror Mr that deflects the optical path by 90 degrees.

[0130] Regarding the projection optical system of Example 1, basic lens data are shown in Table 1A and Table 1B, specifications and variable surface intervals are shown in Table 2, and aspheric coefficients are shown in Table 3. Here, in order to avoid the lengthening of one table, the basic lens data are divided into two tables, Table 1A and Table 1B. The first optical system G1 is shown in Table 1A, and the second optical system G2 is shown in Table 1B.

[0131] The table of basic lens data is as follows. In the Sn column, the surface numbers are shown with the surface closest to the magnification side as the first surface and the numbers increasing one by one toward the reduction side. Among them, "Prs" is recorded in the surface number column of the surface corresponding to the reflection surface Prs, and "Mr" is recorded in the surface number column of the surface corresponding to the plane mirror Mr. In addition, in the surface number column of the surface corresponding to the aperture stop St, the surface number and "(St)" are recorded. In the R column, the radius of curvature of each surface is shown. In the D column, the surface spacing on the optical axis between each surface and the surface adjacent to its reduction side is shown. In the Nd column, the refractive index of each component relative to the d-line is shown. In the νd column, the Abbe number of each component based on the d-line is shown. In the ER column, the maximum effective radius of each surface is shown. In the AH column, the height of the on-axis edge light ray B0m of each surface from the optical axis Z is shown. The value shown in the AH column is the maximum value in the entire zoom range.

[0132] In the table of basic lens data, the sign of the curvature radius of the surface that makes the convex shape toward the magnification side is set to positive, and the sign of the curvature radius of the surface that makes the convex shape toward the reduction side is set to negative. In the table of basic lens data, the symbol DD[] is used for the variable surface interval when changing magnification, and the surface number on the magnification side of the interval is marked in [] and recorded in the D column.

[0133] In Table 2, the zoom ratio Zr, the absolute value of the focal length f, the back focus Bf measured in terms of air conversion distance, the F value FNo., the maximum total angle of view 2ω, and the variable surface interval are indicated by the d-line reference. The [°] in the 2ω column indicates that the unit is degree. In Table 2, the columns labeled "Wide" and "Tele" respectively show the values ​​of the wide-angle end state and the telephoto end state.

[0134] In the basic lens data, the surface number of the aspheric surface is marked with an *, and the value of the paraxial curvature radius is recorded in the curvature radius column of the aspheric surface. In Table 3, the surface number of the aspheric surface is shown in the Sn row, and the numerical values ​​of the aspheric coefficients of each aspheric surface are shown in the KA and Am (m = 3, 4, 5, 6, ..., 20) rows. The "E±n" (n: integer) numerical values ​​of the aspheric coefficients in Table 3 refer to "×10 ±n KA and Am are aspherical coefficients in the aspherical formula represented by the following formula.

[0135] Zd=C×h 2 / {1+(1-KA×C 2 ×h 2 ) 1 / 2}+∑Am×h m

[0136] in,

[0137] Zd: depth of aspheric surface (the length of the perpendicular line from a point on the aspheric surface at height h to a plane tangent to the vertex of the aspheric surface and perpendicular to the optical axis Z);

[0138] h: height (the distance from the optical axis Z to the lens surface);

[0139] C: the reciprocal of the paraxial curvature radius;

[0140] KA, Am: Aspheric coefficients,

[0141] The ∑ of the aspherical type is the sum related to m.

[0142] In the data of each table, degrees are used as the unit of angle, and mm (millimeter) is used as the unit of length. Since the optical system can be used in both enlarged and reduced proportions, other appropriate units can also be used. In addition, the values ​​rounded to a specified number of digits are recorded in each table shown below.

[0143] [Table 1A] Example 1

[0144] Sn R D Nd vd ER AH *1 55.4661 1.4326 1.85135 40.10 14.000 2.331 *2 13.0558 9.6112 10.583 2.298 3 -32.5700 1.1781 1.43700 95.10 9.484 3.418 4 19.9925 2.2649 8.795 3.615 5 27.2753 5.4996 1.86314 39.62 8.974 4.201 6 -64.0682 0.4229 8.708 4.501 7 -46.2386 1.0954 1.55871 46.08 8.652 4.519 8 1307.5561 4.7797 8.457 4.609 9 ∞ 10.0000 1.71299 53.87 7.774 5.123 Prs ∞ 10.0000 1.71299 53.87 - - 10 ∞ 2.0000 8.500 6.376 11 ∞ 1.5429 1.84850 43.79 9.578 6.592 12 -90.1791 0.1205 9.844 6.667 13 104.2212 2.0349 1.90265 35.77 10.324 6.693 14 -160.5365 1.8050 10.501 6.681 15 -12636.1009 1.5152 1.77561 32.21 10.993 6.579 16 24.4442 6.4041 1.59282 68.62 11.558 6.509 17 -47.6438 16.3917 11.980 6.508 18 90.0046 1.9995 1.83897 25.48 15.633 5.093 19 51.6637 1.1605 15.689 4.944 20 87.2454 1.6306 1.76650 27.90 15.741 4.891 21 47.5342 10.2174 1.52841 76.45 16.031 4.800 22 -57.2897 5.6282 16.880 4.359 *23 -43.3566 6.9499 1.51623 64.05 17.495 3.139 *24 -63.4052 11.3084 18.791 3.434 25 167.8508 10.0000 1.90996 19.46 23.273 2.376 26 -164.8461 8.8085 23.951 1.828 *27 46.1822 8.1977 1.51007 56.24 25.038 0.801 *28 40.5431 19.2956 24.013 0.130

[0145] [Table 1B]

[0146] Example 1

[0147] Sn R D Nd νd ER AH 29 86.6404 5.6681 1.91001 36.51 25.991 2.273 30 5524.0670 34.7570 25.873 2.565 Mr ∞ DD

[30] - - 31 129.8877 1.5106 1.51860 69.89 16.109 10.361 32 29.7122 9.1201 1.43700 95.10 15.911 10.464 33 -47.8171 0.1203 15.903 10.812 34 51.3729 5.0098 1.80809 22.74 15.044 10.768 35 1166.9307 0.1000 14.390 10.355 36 80.4971 1.9990 1.61212 36.74 13.867 10.224 37 51.6449 DD

[37] 13.055 9.848 38 25.9182 9.5222 1.72846 55.03 12.166 9.584 39 63.1918 2.0324 9.086 7.557 40 -24139.9598 1.3556 1.67361 32.11 8.117 7.003 41 17.0824 3.4448 7.065 6.474 42 -30.2900 1.9991 1.84648 24.12 6.709 6.377 43 -255.3679 0.1000 6.581 6.542 44(St) ∞ 1.4366 6.560 6.560 45 -464.6426 3.7641 1.80817 48.65 6.939 6.109 46 -25.0208 DD

[46] 7.357 6.895 47 -23.8127 1.8860 1.89286 20.36 7.503 6.452 48 88.6952 0.2234 8.097 6.659 49 112.9907 4.4054 1.43875 94.66 8.163 6.694 50 -37.2521 5.1522 8.975 7.118 51 -1270.9380 4.3323 1.81110 28.65 12.103 7.685 52 -36.2710 DD

[52] 12.718 7.864 53 52.2089 5.9995 1.72916 54.61 15.389 7.258 54 -186.0535 12.3352 15.368 6.663 55 ∞ 23.0000 1.51633 64.14 14.426 3.888 56 ∞ 3.0000 1.48749 70.44 13.327 0.560 57 ∞ 0.5049 13.184 0.117

[0148] [Table 2] Example 1

[0149] Wide Tele Zr 1.00 1.15 |f| 10.26 11.80 Bf 29.96 29.94 FNo. 2.3 2.5 2ω[°] 104.4 96.6 DD[301 49.14 40.73 DD

[37] 0.92 1.22 DD

[46] 3.21 5.22 DD

[52] 5.41 11.52

[0150] [Table 3]

[0151] Example 1

[0152] Sn 1 2 23 24 KA 1.0000000E+00 1.0000000E+00 1.0000000E+00 1.0000000E+00 A3 -2.4593902E-04 -1.5584110E-04 -1.0968426E-05 -3.8343722E-05 A4 2.4332496E-04 2.5981924E-04 6.2879283E-06 3.4681362E-05 A5 -1.0572463E-05 -1.7860592E-05 2.9621638E-06 -2.7033865E-06 A6 -5.3949936E-06 -8.3491770E-06 2.6161942E-08 5.0981941E-07 A7 5.9098467E-07 1.8611166E-06 -4.0955743E-08 2.1842210E-10 A8 5.0533088E-08 -1.9060062E-08 4.7147176E-10 -7.9044432E-09 A9 -9.9523006E-09 -4.6162863E-08 3.2504256E-10 3.9829721E-10 A10 -8.2327068E-11 5.5308896E-09 -5.9777206E-12 4.7083609E-11 A11 8.3062404E-11 3.6762772E-10 -1.6934531E-12 -3.8499584E-12 A12 -2.0368362E-12 -1.1394439E-10 3.9096192E-14 -1.1715551E-13 A13 -3.8107237E-13 2.6335832E-12 5.5493626E-15 1.6412310E-14 A14 1.7076147E-14 9.9570558E-13 -1.5362499E-16 1.5851739E-17 A15 9.5012085E-16 -6.7135567E-14 -1.0757647E-17 -3.6275704E-17 A16 -5.9337785E-17 -3.3698633E-15 3.4028375E-19 4.9449822E-19 A17 -1.1308829E-18 4.3383214E-16 1.1165761E-20 4.0568931E-20 A18 9.7332939E-20 -2.3130246E-18 -3.8624133E-22 -9.0400917E-22 A19 4.0583938E-22 -9.5984432E-19 -4.7608019E-24 -1.8166065E-23 A20 -6.0219046E-23 2.7977393E-20 1.7367763E-25 5.0923109E-25

[0153] Sn 27 28 KA 1.0000000E+00 1.0000000E+00 A3 2.4369099E-04 1.0637544E-03 A4 -5.1802200E-05 -1.3632167E-04 A5 2.0802070E-06 -6.8692714E-06 A6 3.0408678E-07 1.8230914E-06 A7 -1.7673594E-08 -3.1543679E-09 A8 -1.3249198E-09 -1.1480385E-08 A9 6.1107858E-11 2.1124449E-10 A10 4.6781038E-12 4.0231747E-11 A11 -1.2051446E-13 -9.6597569E-13 A12 -1.1943463E-14 -8.5307476E-14 A13 1.5446305E-16 2.0959335E-15 A14 1.9795275E-17 1.1249126E-16 A15 -1.3534868E-19 -2.4629487E-18 A16 -1.9825578E-20 -9.0535997E-20 A17 7.4116501E-23 1.5051303E-21 A18 1.0838744E-23 4.0818345E-23 A19 -1.8376356E-26 -3.7437512E-25 A20 -2.4763175E-27 -7.9114102E-27

[0154] Fig. 9 , various aberration diagrams of the projection optical system of Example 1 are shown when the projection distance is 1.55 m (meters). The projection distance is the distance on the optical axis from the projection surface to the lens surface closest to the magnification side. Fig. 9In the figure, spherical aberration, astigmatism, distortion aberration, and lateral chromatic aberration are shown from left to right. In the spherical aberration diagram, aberrations related to the d-line, C-line, and F-line are shown with solid lines, long dashed lines, and short dashed lines, respectively. In the astigmatism diagram, aberrations related to the d-line in the sagittal direction are shown with solid lines, and aberrations related to the d-line in the meridional direction are shown with short dashed lines. In the distortion aberration diagram, aberrations related to the d-line are shown with solid lines. In the lateral chromatic aberration diagram, aberrations related to the C-line and F-line are shown with long dashed lines and short dashed lines, respectively. In the spherical aberration diagram, the value of the F value is shown after "FNo.=". In the other aberration diagrams, the value of the maximum half viewing angle is shown after "ω=".

[0155] Unless otherwise specified, the symbols, meanings, recording methods, and illustration methods of various data related to the above-mentioned embodiment 1 are basically the same in the following embodiments, and therefore repeated descriptions are omitted below.

[0156] [Example 2]

[0157] The structure of the projection optical system and the cross-sectional view of the light flux of Example 2 are shown in FIG. Fig.10 A cross-sectional view of the optical path of the projection optical system of Example 2 is shown in FIG. Fig.11 The projection optical system of Example 2 includes a first optical system G1 and a second optical system G2 in order from the magnification side to the reduction side along the optical path, and an intermediate image MI is formed between the first optical system G1 and the second optical system G2.

[0158] The first optical system G1 includes a front group G1F, a prism Pr, and a rear group G1R in order from the magnification side to the reduction side along the optical path. The front group G1F includes lenses L1a to L1d in order from the magnification side to the reduction side along the optical path. The rear group G1R includes lenses L1e to L1n in order from the magnification side to the reduction side along the optical path. The reflection surface Prs inside the prism Pr functions as an optical path deflection surface that deflects the optical path by 90 degrees. The focusing group includes lenses L1g to L11.

[0159] The second optical system G2 includes, in order from the magnification side to the reduction side, the 2A lens group G2A, the plane mirror Mr, the 2B lens group G2B, the 2C lens group G2C, the 2D lens group G2D, and the 2E lens group G2E along the optical path. The 2A lens group G2A includes lens L2a. The 2B lens group G2B includes lenses L2b to L2e. The 2C lens group G2C includes lenses L2f to L2h, an aperture stop St, and lenses L2i to L2j. The 2D lens group G2D includes lenses L2k to L2m. The 2E lens group G2E includes lens L2n. When changing the magnification, the 2A lens group G2A and the 2E lens group G2E are fixed on the display surface Sim, and the 2B lens group G2B, the 2C lens group G2C, and the 2D lens group G2D change the intervals with the adjacent lens groups and move along the optical axis Z. The plane mirror Mr functions as an optical path deflecting surface for deflecting the optical path by 90 degrees.

[0160] Regarding the projection optical system of Example 2, basic lens data are shown in Tables 4A and 4B, specifications and variable surface spacing are shown in Table 5, aspheric coefficients are shown in Table 6, and various aberration diagrams are shown in Table 8. Fig.12 Each aberration diagram is a diagram when the projection distance is 1.55 m (meter).

[0161] [Table 4A]

[0162] Example 2

[0163] Sn R D Nd νd ER AH *1 48.4236 1.1001 1.85135 40.10 14.000 2.443 *2 13.0628 9.4046 10.943 2.411 3 -34.0606 1.0001 1.44357 88.81 10.467 3.503 4 20.1686 2.3467 10.021 3.679 5 26.8039 5.1211 1.87572 39.71 10.258 4.295 6 -64.2992 0.4281 9.980 4.553 7 -46.3881 1.3572 1.54626 62.35 9.926 4.569 8 -8402.6270 4.1608 9.542 4.668 9 ∞ 10.0000 1.71299 53.87 8.500 5.072 Prs ∞ 10.0000 1.71299 53.87 - - 10 ∞ 2.0000 8.500 6.201 11 ∞ 1.7077 1.84850 43.79 9.616 6.395 12 -91.7061 0.1200 9.934 6.472 13 104.9199 2.0482 1.90265 35.77 10.438 6.492 14 -162.6580 3.2808 10.623 6.474 15 -4952.3799 1.5008 1.78880 28.42 11.502 6.283 16 24.2648 7.1431 1.59410 60.47 12.145 6.212 17 -47.0946 14.3378 12.653 6.202 18 85.5795 1.5006 1.76079 30.28 16.413 4.970 19 51.1078 1.9140 16.494 4.856 20 85.4665 1.5001 1.88236 30.25 16.795 4.158 21 49.1983 8.0260 1.52731 75.16 17.018 4.670 22 -50.5847 5.3003 17.385 4.322 *23 -43.8618 6.6221 1.51623 64.05 17.988 3.102 *24 -60.7351 10.3192 19.211 3.380 25 173.0631 5.2008 1.91000 19.46 23.208 2.329 26 -171.6878 9.3727 23.411 2.025 *27 43.9674 8.1188 1.51007 56.24 24.596 0.855 *28 38.7487 19.1475 23.431 0.142

[0164] [Table 4B] Example 2

[0165] Sn R D Nd νd ER AH 29 84.5114 6.7423 1.87140 24.81 25.889 2.420 30 4988.0432 39.7070 25.737 2.801 Mr ∞ DD

[30] - - 31 95.1999 1.5009 1.57099 50.80 19.097 11.966 32 26.6600 11.1982 1.55032 75.50 18.457 12.031 33 -97.1306 0.1202 18.294 12.221 34 51.0227 4.0252 1.91000 36.31 17.132 12.147 35 543.6240 0.1000 16.742 11.792 36 84.4754 1.3798 1.48750 61.11 15.944 11.608 37 55.8501 DD

[37] 15.179 11.255 38 34.7378 6.1641 1.88972 31.91 14.159 10.936 39 3356.6178 0.1647 12.744 9.773 40 1399.7529 5.3163 1.85451 25.15 12.509 9.672 41 51.6937 2.0324 9.674 8.069 42 -843.4900 1.8530 1.63984 36.51 8.877 7.558 43 17.2426 4.4449 7.489 6.849 44(St) ∞ 1.2200 6.604 6.604 45 -28.0717 1.2002 1.76203 26.89 6.665 6.573 46 333.1824 0.4862 7.055 6.707 47 149.2192 2.6801 1.79350 50.13 7.270 6.183 48 -27.8054 DD

[48] 7.520 6.870 49 -22.6796 1.2004 1.89286 20.36 7.894 6.458 50 88.6952 0.1845 8.545 6.645 51 112.9907 3.4344 1.43875 94.66 8.602 6.675 52 -27.8000 8.2045 9.127 6.988 53 -490.6920 4.1713 1.88144 24.70 13.180 7.104 54 -38.2290 DD

[54] 13.705 7.873 55 52.0708 5.4090 1.69560 59.05 16.287 7.634 56 -166.5303 12.3352 16.251 7.085 57 ∞ 23.0000 1.51633 64.14 14.943 4.171 58 ∞ 3.0000 1.48749 70.44 13.439 0.687 59 ∞ 0.9514 13.239 0.224

[0166] [Table 5] Example 2

[0167] Wide Tele Zr 1.00 1.15 |f| 10.25 11.79 Bf 30.40 30.38 FNo. 2.2 2.4 2ω[°] 104.0 96.4 DD

[30] 51.32 42.81 DD

[37] 0.94 1.38 DD

[48] 3.21 5.36 DD

[54] 1.13 7.06

[0168] [Table 6]

[0169] Example 2

[0170] Sn 1 2 23 24 KA 1.0000000E+00 1.0000000E+00 1.0000000E+00 1.0000000E+00 A3 -2.4395674E-04 -2.0636963E-04 -9.6774835E-06 -3.6872622E-05 A4 2.4102913E-04 2.5095320E-04 7.7452762E-06 3.4068742E-05 A5 -1.0498608E-05 -1.4070929E-05 2.9186023E-06 -2.6922482E-06 A6 -5.3405823E-06 -8.1075050E-06 -3.0821221E-11 5.2069539E-07 A7 5.8534489E-07 1.6958391E-06 -4.0497421E-08 -2.7640254E-10 A8 4.9714033E-08 -1.9339357E-08 7.6074809E-10 -8.0171753E-09 A9 -9.8261705E-09 -4.1881091E-08 3.2342705E-10 4.0375327E-10 A10 -7.4543885E-11 5.3860015E-09 -7.9926685E-12 4.7775790E-11 A11 8.1639891E-11 2.9945916E-10 -1.6954644E-12 -3.8808383E-12 A12 -2.0836008E-12 -1.1004476E-10 4.7992720E-14 -1.1979815E-13 A13 -3.7196382E-13 3.3076681E-12 5.5806501E-15 1.6510857E-14 A14 1.7251268E-14 9.4545835E-13 -1.7825711E-16 2.2161158E-17 A15 9.1653687E-16 -7.1173003E-14 -1.0850626E-17 -3.6453922E-17 A16 -5.9729744E-17 -3.0129092E-15 3.8151859E-19 4.8540446E-19 A17 -1.0644149E～18 4.4725343E-16 1.1286119E-20 4.0739329E-20 A18 9.7810153E-20 -3.6544451E-18 -4.2428173E-22 -8.9682291E-22 A19 3.5114197E-22 -9.7886443E-19 -4.8200712E-24 -1.8233051E-23 A20 -6.0464134E-23 3.0063539E-20 1.8849956E-25 5.0685609E-25

[0171] Sn 27 28 KA 1.0000000E+00 1.0000000E+00 A3 2.2525733E-04 1.1302044E-03 A4 -5.3223601E-05 -1.3977962E-04 A5 2.3673330E-06 -7.6931590E-06 A6 3.2537079E-07 1.8538876E-06 A7 -2.0161644E-08 2.0083361E-09 A8 -1.4757407E-09 -1.1639746E-08 A9 7.2937229E-11 1.9153278E-10 A10 5.2787388E-12 4.0742808E-11 A11 -1.5289625E-13 -9.1806091E-13 A12 -1.3374041E-14 -8.6356556E-14 A13 2.0696929E-16 2.0226481E-15 A14 2.1873269E-17 1.1386966E-16 A15 -1.8516737E-19 2.3953502E-18 A16 -2.1628138E-20 -9.1654814E-20 A17 9.9676089E-23 1.4709578E-21 A18 1.1696307E-23 4.1328187E-23 A19 -2.3852095E-26 -3.6712248E-25 A20 -2.6484155E-27 -8.0110037E-27

[0172] [Example 3]

[0173] The structure of the projection optical system and the cross-sectional view of the light flux of Example 3 are shown in FIG. Fig.13 A cross-sectional view of the optical path of the projection optical system of Example 3 is shown in FIG. Fig.14The projection optical system of Example 3 includes a first optical system G1 and a second optical system G2 in order from the magnification side to the reduction side along the optical path, and an intermediate image MI0 is formed between the first optical system G1 and the second optical system G2.

[0174] The first optical system G1 includes a front group G1F, a prism Pr, and a rear group G1R in order from the magnification side to the reduction side along the optical path. The front group G1F includes lenses L1a to L1d in order from the magnification side to the reduction side along the optical path. The rear group G1R includes lenses L1e to L1n in order from the magnification side to the reduction side along the optical path. The reflection surface Prs inside the prism Pr functions as an optical path deflection surface that deflects the optical path by 90 degrees. The focusing group includes lenses L1g to L11.

[0175] The second optical system G2 includes, in order from the magnification side to the reduction side, a 2A lens group G2A, a plane mirror Mr, a 2B lens group G2B, a 2C lens group G2C, a 2D lens group G2D, a 2E lens group G2E, and a 2F lens group G2F. The 2A lens group G2A includes a lens L2a. The 2B lens group G2B includes lenses L2b to L2e. The 2C lens group G2C includes lenses L2f to L2g. The 2D lens group G2D includes a lens L2h, an aperture stop St, and lenses L2i to L2j. The 2E lens group G2E includes lenses L2k to L2m. The 2F lens group G2F includes a lens L2n. When changing the magnification, the 2A lens group G2A and the 2F lens group G2F are fixed on the display surface Sim, and the 2B lens group G2B, the 2C lens group G2C, the 2D lens group G2D, and the 2E lens group G2E change the intervals between the adjacent lens groups and move along the optical axis Z. The plane mirror Mr functions as an optical path deflecting surface that deflects the optical path by 90 degrees.

[0176] Regarding the projection optical system of Example 3, basic lens data are shown in Tables 7A and 7B, specifications and variable surface spacing are shown in Table 8, aspheric coefficients are shown in Table 9, and various aberration diagrams are shown in Table 10. Fig.15 Each aberration diagram is a diagram when the projection distance is 1.55 m (meter).

[0177] [Table 7A] Example 3

[0178] Sn R D Nd νd ER AH *1 51.8527 1.1176 1.85135 40.10 14.000 2.329 *2 13.0849 9.7306 10.916 2.302 3 -34.5112 1.0003 1.44687 88.43 10.326 3.409 4 20.2308 2.3960 9.896 3.576 5 26.1333 4.3328 1.87422 39.90 10.137 4.187 6 -64.0876 0.4235 9.950 4.399 7 -46.6061 1.0666 1.54236 73.24 9.895 4.415 8 -1190974.0101 4.2967 9.560 4.494 9 ∞ 10.0000 1.71299 53.87 8.500 4.902 Prs ∞ 10.0000 1.71299 53.87 - - 10 ∞ 2.0000 8.500 6.007 11 ∞ 1.6394 1.84850 43.79 9.603 6.197 12 -92.7529 0.1210 9.902 6.271 13 105.7967 2.0322 1.90265 35.77 10.395 6.290 14 -166.8938 2.6214 10.580 6.274 15 2931.5541 1.5003 1.78880 28.42 11.294 6.134 16 24.0765 6.9364 1.59410 60.47 11.929 6.071 17 47.8578 15.7348 12.431 6.078 18 85.2697 1.5008 1.77050 29.66 16.577 4.858 19 51.3624 1.9794 16.659 4.751 20 84.7300 1.5000 1.90881 36.72 16.995 4.662 21 49.4874 8.2063 1.53861 73.93 17.213 4.581 22 -49.1041 5.3847 17.568 4.263 *23 -43.5868 6.7759 1.51623 64.05 18.146 3.661 *24 -58.0750 11.0761 19.309 3.355 25 175.2052 5.0001 1.91000 19.52 23.412 2.271 26 -205.5821 9.5640 23.605 1.990 *27 45.7200 8.3113 1.51007 56.24 24.939 0.858 *28 40.2400 19.7669 23.591 0.162

[0179] [Table 7B]

[0180] Example 3

[0181]

[0182] [Table 8] Example 3

[0183] Wide Tele Zr 1.00 1.15 |f| 10.26 11.80 Bf 29.97 29.95 FNo. 2.3 2.5 2ω[°] 104.8 96.8 DD

[30] 49.54 40.58 DD

[37] 0.94 1.41 DD

[41] 2.07 2.00 DD

[48] 3.21 4.90 DD

[54] 3.87 10.73

[0184] [Table 9]

[0185] Example 3

[0186] Sn 1 2 23 24 KA 1.0000000E+00 1.0000000E+00 1.0000000E+00 1.0000000E+00 A3 -4.0974740E-05 1.1561689E-04 5.5398457E-05 3.2081785E-05 A4 9.7134805E-05 2.7997076E-05 -1.1455787E-05 9.4623093E-06 A5 -4.9095987E-06 1.5026191E-05 2.3474894E-06 -1.6433918E-06 A6 1.1791956E-07 -4.5926785E-06 5.5089662E-07 7.7764943E-07 A7 7.9405414E-08 1.4868092E-07 -6.3320933E-08 -1.6378125E-08 A8 -3.7263488E-08 2.0534231E-07 -4.7435005E-09 -9.2280303E-09 A9 2.0185181E-09 -3.1730803E-08 7.3348168E-10 4.7764533E-10 A10 5.5825545E-10 -3.4267698E-09 1.6402293E-11 5.0690497E-11 A11 -5.5078616E-11 9.6300750E-10 -4.5582968E-12 -3.9136378E-12 A12 -3.2116524E-12 8.4926775E-12 1.3345840E-14 -1.2557178E-13 A13 5.1272752E-13 -1.3277846E-11 1.6052678E-14 1.5716519E-14 A14 4.1304009E-15 3.8462387E-13 -2.7910859E-16 4.2497706E-17 A15 -2.3517279E-15 9.3426675E-14 -3.2041514E-17 -3.3697803E-17 A16 3.3802047E-17 -4.6161436E-15 8.5570179E-19 4.2762120E-19 A17 5.3796403E-18 -3.2123019E-16 3.3758519E-20 3.6976604E-20 A18 -1.4545891E-19 2.0293668E-17 -1.1237648E-21 -8.1733732E-22 A19 -4.9128890E-21 4.1698744E-19 -1.4577835E-23 -1.6328460E-23 A20 1.7272758E-22 -3.1243194E-20 5.5797714E-25 4.6598177E-25

[0187] Sn 27 28 KA 1.0000000E+00 1.0000000E+00 A3 3.71162047E-04 5.5067947E-04 A4 -7.6907998E-05 -3.9753037E-05 A5 1.4059114E-06 -3.7292776E-06 A6 6.3495144E-07 3.2581882E-07 A7 -2.7334338E-08 8.8384466E-09 A8 -2.6983425E-09 -1.0595168E-09 A9 1.4261145E-10 -7.9425591E-12 A10 6.5504918E-12 7.3837701E-13 A11 -3.8432694E-13 2.5375054E-14 A12 -9.2583166E-15 4.0860946E-15 A13 6.0050919E-16 -1.1465338E-16 A14 7.2724826E-18 -1.2011968E-17 A15 -5.4900926E-19 2.0611682E-19 A16 -2.6201004E-21 1.4218192E-20 A17 2.7282979E-22 -1.6105774E-22 A18 3.5256417E-26 -8.0652303E-24 A19 -5.6980627E-26 4.6529023E-26 A20 1.5638821E-28 1.8053546E-27

[0188] [Example 4]

[0189] The structure of the projection optical system and the cross-sectional view of the light flux of Example 4 are shown in FIG. Fig.16 A cross-sectional view of the optical path of the projection optical system of Example 4 is shown in FIG. Fig.17 The projection optical system of Example 4 includes a first optical system G1 and a second optical system G2 in order from the magnification side to the reduction side along the optical path, and an intermediate image MI0 is formed between the first optical system G1 and the second optical system G2.

[0190] The first optical system G1 includes a front group G1F, a prism Pr, and a rear group G1R in order from the magnification side to the reduction side along the optical path. The front group G1F includes lenses L1a to L1e in order from the magnification side to the reduction side along the optical path. The rear group G1R includes lenses L1f to L1o in order from the magnification side to the reduction side along the optical path. The reflection surface Prs inside the prism Pr functions as an optical path deflection surface that deflects the optical path by 90 degrees. The focusing group includes lenses L1h to L1m.

[0191] The second optical system G2 includes, in order from the magnification side to the reduction side, the 2A lens group G2A, the plane mirror Mr, the 2B lens group G2B, the 2C lens group G2C, the 2D lens group G2D, and the 2E lens group G2E along the optical path. The 2A lens group G2A includes lens L2a. The 2B lens group G2B includes lenses L2b to L2e. The 2C lens group G2C includes lenses L2f to L2g, an aperture stop St, and lenses L2h to L2i. The 2D lens group G2D includes lenses L2j to L21. The 2E lens group G2E includes lens L2m. When changing the magnification, the 2A lens group G2A and the 2E lens group G2E are fixed on the display surface Sim, and the 2B lens group G2B, the 2C lens group G2C, and the 2D lens group G2D change the intervals with the adjacent lens groups and move along the optical axis Z. The plane mirror Mr functions as an optical path deflecting surface for deflecting the optical path by 90 degrees.

[0192] Regarding the projection optical system of Example 4, basic lens data are shown in Tables 10A and 10B, specifications and variable surface spacing are shown in Table 11, aspheric coefficients are shown in Table 12, and various aberration diagrams are shown in Table 13. Fig.18Each aberration diagram is a diagram when the projection distance is 1.55 m (meter).

[0193] [Table 10A] Example 4

[0194] Sn R D Nd νd ER AH *1 47.8152 1.2606 1.85135 40.10 14.000 2.337 *2 12.8855 9.7591 10.676 2.303 3 -30.9716 1.0023 1.43700 95.10 9.692 3.401 4 19.6661 2.3807 8.903 3.576 5 26.8280 3.2573 1.87034 40.88 9.072 4.190 6 9304.9977 0.1202 8.895 4.358 7 -1387.3530 1.0010 1.55832 45.03 8.879 4.370 8 47.6368 0.5786 8.699 4.455 9 63.7999 3.2519 1.81850 42.58 8.683 4.543 10 1180.3462 3.8226 8.452 4.718 11 ∞ 10.0000 1.71299 53.87 7.876 5.127 Prs ∞ 10.0000 1.71299 53.87 - - 12 ∞ 2.0000 8.500 6.370 13 ∞ 1.6819 1.84850 43.79 9.576 6.584 14 -90.2206 0.121 9.877 6.667 15 104.2097 2.1263 1.90265 35.77 10.359 6.692 16 -160.3950 1.4528 10.548 6.678 17 -13989.4635 1.5001 1.77971 31.90 10.957 6.594 18 24.4484 6.5699 1.59282 68.62 11.511 6.523 19 -47.5919 16.3868 11.974 6.523 20 89.9903 1.9707 1.83685 28.11 15.627 5.111 21 51.6602 1.2579 15.684 4.964 22 87.2175 1.6512 1.76600 28.73 15.770 4.906 23 47.5685 10.2776 1.52841 76.45 16.061 4.813 24 -57.1845 5.8142 16.914 4.371 *25 -43.4160 7.0999 1.51623 64.05 17.539 3.729 *26 -63.3853 11.5240 18.856 3.415 27 166.8842 9.3602 1.90975 19.76 23.420 2.333 28 -162.5925 8.7117 24.021 1.819 *29 46.1391 7.9516 1.51007 56.24 25.036 0.802 *30 40.5409 18.4457 24.029 0.148

[0195] [Table 10B]

[0196] Example 4

[0197]

[0198] [Table 11]

[0199] Example 4

[0200] Wide Tele Zr 1 1.15 |f| 10.26 11.79 Bf 30.65 30.63 FNo. 2.3 2.5 2ω[°] 104.2 96.4 DD

[32] 54 45.77 DD

[39] 0.94 1.26 DD

[48] 3.21 5.37 DD

[54] 4.14 9.88

[0201] [Table 12]

[0202] Example 4

[0203] Sn 1 2 25 26 KA 1.0000000E+00 1.0000000E+00 1.0000000E+00 1.0000000E+00 A3 -2.5362436E-04 -2.5435783E-04 1.2863124E-05 -3.4184462E-05 A4 2.5153380E-04 2.7471118E-04 5.0933375E-06 3.5180530E-05 A5 -1.0191539E-05 -7.4110073E-06 2.4099278E-06 -2.8148316E-06 A6 -5.7374933E-06 -1.0159658E-05 3.8439563E-08 4.9190492E-07 A7 5.8036604E-07 1.3257858E-06 -3.4036627E-08 1.7188671E-09 A8 5.8140470E-08 7.4989630E-08 4.4124905E-10 -7.6833004E-09 A9 -9.8275091E-09 -3.1289053E-08 2.7456531E-10 3.8851191E-10 A10 -1.8113197E-10 2.8680736E-09 -6.4161388E-12 4.5652846E-11 A11 8.2538943E-11 1.2312694E-10 -1.4726017E-12 -3.8182135E-12 A12 -1.2466625E-12 -6.8894374E-11 4.3148273E-14 -1.1181477E-13 A13 -3.8245430E-13 5.0783244E-12 4.9654112E-15 1.6369439E-14 A14 1.3133644E-14 5.2857242E-13 -1.6877601E-16 4.0723245E-18 A15 9.7058577E-16 -8.1678575E-14 -9.8479903E-18 -3.6289639E-17 A16 -4.7380601E-17 -4.6214315E-16 3.6985398E-19 5.0945514E-19 A17 -1.1988099E-18 4.8088493E-16 1.0400660E-20 4.0664022E-20 A18 7.7159126E-20 -1.2284789E-17 -4.1592484E-22 -9.1392514E-22 A19 4.8245222E-22 -1.0231752E-18 -4.4940690E-24 -1.8235044E-23 A20 -4.5688146E-23 4.2459394E-20 1.8580499E-25 5.1180323E-25

[0204] Sn 29 30 KA 1.0000000E+00 1.0000000E+00 A3 2.7151012E-04 1.0576983E-03 A4 -5.6211750E-05 -1.3775220E-04 A5 2.0484855E-06 -6.2255200E-06 A6 3.5486906E-07 1.8481872E-06 A7 -1.8864375E-08 -1.0054130E-08 A8 -1.6388025E-09 -1.1694898E-08 A9 6.9182121E-11 2.4454952E-10 A10 5.8343355E-12 4.1175930E-11 A11 -1.4460983E-13 -1.0547207E-12 A12 -1.4560704E-14 -8.7666119E-14 A13 1.9406829E-16 2.2346569E-15 A14 2.3455593E-17 1.1597507E-16 A15 -1.7253786E-19 -2.5896168E-18 A16 -2.2904236E-20 -9.3553384E-20 A17 9.2861154E-23 1.5676949E-21 A18 1.2265023E-23 4.2237268E-23 A19 -2.2318783E-26 -3.8729309E-25 A20 -2.7558203E-27 -8.1915463E-27

[0205] Table 13 shows the corresponding values ​​of conditional expressions (1) to (10) and the values ​​of Imax and DifP in the projection optical systems of Examples 1 to 4. The corresponding values ​​of the examples shown in Table 13 may be used as the upper limit or lower limit of the conditional expression to set the preferred range of the conditional expression.

[0206] [Table 13]

[0207]

[0208] The projection optical systems of Examples 1 to 4 have a full viewing angle of 100 degrees or more at the wide-angle end and have a wide angle. The F value at the wide-angle end of the projection optical systems of Examples 1 to 4 is 2.3 or less and has a small F value. In addition, in the projection optical systems of Examples 1 to 4, although they are compactly constructed, various aberrations are well corrected to achieve high optical performance.

[0209] Generally, there are many cases where a projection optical system requires a projection image with a wide viewing angle, and in recent years, there are also many cases where a large screen can be projected from near the screen. As a result, the lens closest to the magnification side of the projection optical system tends to be large-scale. In contrast, according to the projection optical system of the present invention, the miniaturization of the lens closest to the magnification side can be achieved. In addition, the projection optical system of the present invention includes an optical path deflection surface, so it can be compactly constructed and has a high degree of freedom in setting.

[0210] Next, a projection display device according to an embodiment of the present invention will be described. Fig.19 It is a schematic structural diagram of a projection display device according to one embodiment of the present invention. Fig.19 The projection display device 100 shown has: a projection optical system 10 according to an embodiment of the present invention; a light source 15; and transmissive display elements 11a to 11c as light valves corresponding to light of various colors and outputting optical images. Furthermore, the projection display device 100 has dichroic mirrors 12 and 13 for color separation, a cross dichroic prism 14 for color synthesis, condensing lenses 16a to 16c, and total reflection mirrors 18a to 18c for deflecting the light path. Fig.19 The projection optical system 10 is schematically shown in FIG. 1 . An integrator is arranged between the light source 15 and the dichroic mirror 12. Fig.19 The illustration is omitted.

[0211] The white light from the light source 15 is decomposed into three color light fluxes (green light, blue light, and red light) by the dichroic mirrors 12 and 13, and then is incident on the transmissive display elements 11a to 11c corresponding to the light fluxes of the respective colors through the condenser lenses 16a to 16c to be modulated, and then is color-synthesized by the cross dichroic prism 14, and then is incident on the projection optical system 10. The projection optical system 10 projects an optical image based on the modulated light modulated by the transmissive display elements 11a to 11c onto the screen 105.

[0212] Fig. 20 It is a schematic structural diagram of a projection display device according to another embodiment of the present invention. Fig. 20 The projection display device 200 shown has: a projection optical system 210 according to an embodiment of the present invention; a light source 215; and DMD (Digital Micromirror Device: registered trademark) elements 21a to 21c as light valves corresponding to light of various colors and outputting optical images. In addition, the projection display device 200 has TIR (Total Internal Reflection) prisms 24a to 24c for color separation and color synthesis, and a polarization beam splitter prism 25 for separating illumination light and projection light. In addition, Fig. 20 The projection optical system 210 is schematically shown in FIG. 2. In addition, an integrator is arranged between the light source 215 and the polarization beam splitting prism 25, but Fig. 20 The illustration is omitted.

[0213] The white light from the light source 215 is reflected by the reflection surface inside the polarization beam splitter prism 25, and then decomposed into three color light fluxes (green light, blue light, and red light) by the TIR prisms 24a to 24c. The decomposed light fluxes of each color light are respectively incident on the corresponding DMD elements 21a to 21c to be modulated, and after the TIR prisms 24a to 24c are reversed again to perform color synthesis, they are transmitted through the polarization beam splitter prism 25 and incident on the projection optical system 210. The projection optical system 210 projects an optical image based on the modulated light modulated by the DMD elements 21a to 21c onto the screen 205.

[0214] Fig.21 It is a schematic structural diagram of a projection display device according to still another embodiment of the present invention. Fig.21 The projection display device 300 shown has: a projection optical system 310 according to an embodiment of the present invention; a light source 315; and reflective display elements 31a to 31c as light valves corresponding to light of various colors and outputting optical images. Furthermore, the projection display device 300 has dichroic mirrors 32 and 33 for color separation, a cross dichroic prism 34 for color synthesis, a total reflection mirror 38 for deflecting the light path, and polarization beam splitting prisms 35a to 35c. In addition, Fig.21 In FIG. 3 , a projection optical system 310 is schematically shown. In addition, an integrator is arranged between the light source 315 and the dichroic mirror 32. Fig.21 The illustration is omitted.

[0215] The white light from the light source 315 is decomposed into three color light fluxes (green light, blue light, and red light) by the dichroic mirrors 32 and 33. The decomposed light fluxes of the various colors pass through the polarization beam splitting prisms 35a to 35c, respectively, and are incident on the reflective display elements 31a to 31c corresponding to the light fluxes of the various colors to be modulated, and after being color-synthesized by the cross dichroic prism 34, they are incident on the projection optical system 310. The projection optical system 310 projects an optical image based on the modulated light modulated by the reflective display elements 31a to 31c onto the screen 305.

[0216] Fig. 22 It is a schematic structural diagram of a projection display device according to still another embodiment of the present invention. Fig. 22 The projection display device 600 shown in the figure has: a projection optical system 66 according to an embodiment of the present invention; a light source 61; and a DMD element 64 as a light valve corresponding to each color of light and outputting an optical image. In addition, the projection display device 600 has a color wheel 62, a light guide optical system 63, and a TIR prism 65. Fig. 22 The projection optical system 66 is schematically shown in FIG.

[0217] In the color wheel 62, color filters of three colors, green, blue, and red, are arranged on the circumference. When the color wheel 62 rotates, the color filters of each color are sequentially embedded in the optical path. The white light from the light source 61 is incident on the rotating color wheel 62 and is time-divided into the luminous flux of three color lights (green light, blue light, and red light). The luminous flux of each color light after time-divided decomposition passes through the light guide optical system 63 and the TIR prism 65, and then enters the DMD element 64 to be modulated, and then passes through the TIR prism 65 again and enters the projection optical system 66. The projection optical system 66 projects the optical image based on the modulated light modulated by the DMD element 64 onto the screen 67.

[0218] The above embodiments and examples are used to illustrate the technology of the present invention, but the technology of the present invention is not limited to the above embodiments and examples, and various modifications are possible. For example, the radius of curvature, surface spacing, refractive index, Abbe number, and aspheric coefficient of each lens are not limited to the values ​​shown in the above embodiments, and other values ​​can be used.

[0219] Furthermore, the projection display device involved in the technology of the present invention is not limited to the above-mentioned structure. For example, the optical components and light valves used for light flux separation or light flux synthesis can be changed in various ways. The light valve is not limited to a method of spatially modulating the light from the light source through the image display element and outputting it as an optical image based on the image data. It can also be a method of outputting the light itself output from the self-luminous image display element as an optical image based on the image data. As a self-luminous image display element, for example, an image display element composed of a two-dimensional arrangement of light-emitting elements such as LED (Light Emitting Diode) or OLED (Organic Light Emitting Diode) can be cited.

[0220] The following supplementary notes are further disclosed with respect to the above-mentioned embodiments and examples.

[0221] [Note 1]

[0222] A projection optical system projects an image on a reduced side onto an enlarged side, wherein:

[0223] The projection optical system does not include a reflective surface having optical power,

[0224] The optical system includes a first optical system and a second optical system in order from the magnification side to the reduction side along the optical path, and an intermediate image is formed between the first optical system and the second optical system.

[0225] The first optical system includes a light path deflecting surface for deflecting the light path.

[0226] When the radius of the maximum effective image circle on the reduction side is set to Imax,

[0227] The distance on the optical axis from the lens surface closest to the magnification side of the first optical system to the light path deflecting surface is Ddef, and

[0228] When the projection optical system is a variable magnification optical system, when Ddef is set to a value at the wide-angle end,

[0229] The projection optical system satisfies the conditional formula (1) represented by the following formula:

[0230] 0.2 <Imax / Ddef<0.7 (1)。

[0231] [Note 2]

[0232] The projection optical system according to Supplement 1, wherein:

[0233] The first optical system includes, in order from the magnification side to the reduction side along the optical path, a front group having negative optical power, an optical path deflecting member including the optical path deflecting surface, and a rear group having positive optical power.

[0234] [Note 3]

[0235] The projection optical system according to Supplement 2, wherein:

[0236] The front group includes one or more positive lenses.

[0237] [Note 4]

[0238] The projection optical system according to Supplement 2 or 3, wherein:

[0239] The outermost periphery of the optically effective surface of the first optical system closest to the magnification side is located closer to the reduction side than an intersection of the optically effective surface and the optical axis in the optical axis direction.

[0240] [Note 5]

[0241] The projection optical system according to any one of Supplementary Notes 2 to 4, wherein:

[0242] The average value of the Abbe numbers of all negative lenses included in the front group on the d-line basis is νnave, and

[0243] When the average value of the d-line Abbe numbers of all the positive lenses included in the front group is defined as vpave,

[0244] The projection optical system satisfies the conditional formula (2) represented by the following formula:

[0245] 10<vnave-vpave<40 (2).

[0246] [Note 6]

[0247] The projection optical system according to any one of Supplementary Notes 2 to 5, wherein:

[0248] The average refractive index of all negative lenses included in the front group with respect to the d-line is Nnave, and

[0249] When the average refractive index of all positive lenses included in the front group with respect to the d-line is Npave,

[0250] The projection optical system satisfies the conditional formula (3) represented by the following formula:

[0251] 0.15 <Npave-Nnave<0.45 (3)。

[0252] [Note 7]

[0253] The projection optical system according to any one of Supplementary Notes 2 to 6, wherein:

[0254] At least a portion of the rear group moves during focusing.

[0255] [Note 8]

[0256] The projection optical system according to any one of Supplementary Notes 1 to 7, wherein:

[0257] The second optical system includes two or more moving groups that move along the optical axis during magnification change.

[0258] [Note 9]

[0259] The projection optical system according to Supplementary Note 8, wherein:

[0260] The moving group closest to the magnification side among the moving groups of the second optical system has positive refractive power.

[0261] [Note 10]

[0262] The projection optical system according to any one of Supplementary Notes 2 to 7, wherein:

[0263] When the air conversion distance on the optical axis from the surface of the front group closest to the reduction side to the surface of the rear group closest to the magnification side is set as Dfr, and when the projection optical system is a variable power optical system, Dfr is set to the value at the wide angle end,

[0264] The projection optical system satisfies the conditional formula (4) represented by the following formula:

[0265] 0.5 <Imax / Dfr<0.9 (4)。

[0266] [Note 11]

[0267] The projection optical system according to any one of Supplementary Notes 1 to 10, wherein:

[0268] The light path deflecting surface is a surface of a prism.

[0269] [Note 12]

[0270] The projection optical system according to Supplement 11, wherein:

[0271] When the thickness of the prism along the optical axis is set to Dpt, and

[0272] When the refractive index of the prism with respect to the d-line is Npr,

[0273] The projection optical system satisfies the conditional formula (5) represented by the following formula:

[0274] 0.9 <Imax / (Dpr / Npr)<1.3 (5)。

[0275] [Note 13]

[0276] The projection optical system according to any one of Supplementary Notes 1 to 12, wherein:

[0277] When the maximum effective radius of the lens surface closest to the magnification side of the first optical system is ERf, and

[0278] When the maximum value of the maximum effective radius of all lens surfaces of the projection optical system is set to ERmax,

[0279] The projection optical system satisfies the conditional formula (6) represented by the following formula:

[0280] 0 <ERf / ERmax<0.7 (6)。

[0281] [Note 14]

[0282] The projection optical system according to any one of Supplementary Notes 1 to 13, wherein:

[0283] The maximum value of the height of the axial marginal light rays from the optical axis on all lens surfaces of the first optical system is set to AH1, and

[0284] When the maximum value of the height of the on-axis marginal rays from the optical axis on all lens surfaces of the second optical system is defined as AH2,

[0285] The projection optical system satisfies the conditional formula (7) represented by the following formula:

[0286] 0 <AH1 / AH2<0.7 (7)。

[0287] [Note 15]

[0288] The projection optical system according to any one of Supplementary Notes 1 to 14, wherein:

[0289] including an aperture stop on the reduction side closer to the intermediate image,

[0290] The real image of the aperture stop exists inside the first optical system.

[0291] When the position of the real image in the optical axis direction is set to a first position, and

[0292] When a light ray emitted from an arbitrary point within the maximum effective image circle on the reduction side and passing through the center of the aperture stop toward the magnification side intersects the optical axis at a position closer to the magnification side than the intermediate image, the position farthest from the first position is set as the second position,

[0293] The intersection point of the optical path deflecting surface and the optical axis is located within a range from the first position to the second position in the optical axis direction.

[0294] [Note 16]

[0295] The projection optical system according to Supplement 15, wherein:

[0296] Let k be a natural number from 1 to 10,

[0297] A point on the maximum effective image circle on the reduced side whose height from the optical axis is k tenths of the radius of the maximum effective image circle is defined as point PHk.

[0298] The position where the light emitted from the point PHk and passing through the center of the aperture stop toward the magnification side intersects the optical axis at a position closer to the magnification side than the intermediate image is set as position Pk, and the position of the position Pk having the longest air conversion distance on the optical axis from the first position is set as a third position,

[0299] The air conversion distance from the first position to the third position is DifP,

[0300] In the sign of DifP, the distance on the reduction side is set as positive and the distance on the enlargement side is set as negative, based on the first position, and

[0301] When the projection optical system is a variable magnification optical system, when DifP is set to a value at the wide-angle end,

[0302] The projection optical system satisfies the conditional formula (8) represented by the following formula:

[0303] -3 <DifP / Imax<-0.2 (8)。

[0304] [Note 17]

[0305] The projection optical system according to Supplementary Note 16, wherein:

[0306] The first optical system includes a front group, an optical path deflecting component including the optical path deflecting surface, and a rear group in order from the magnification side to the reduction side along the optical path.

[0307] The air conversion distance on the optical axis from the surface of the front group closest to the reduction side to the surface of the rear group closest to the magnification side is denoted as Dfr, and

[0308] When the projection optical system is a variable magnification optical system, Dfr is set to a value at the wide-angle end.

[0309] The projection optical system satisfies the conditional formula (9) represented by the following formula:

[0310] 0.4<|DifP / Dfr|<0.7 (9).

[0311] [Note 18]

[0312] The projection optical system according to any one of Supplementary Notes 12 to 16, wherein:

[0313] The light path deflecting surface is a surface of a prism.

[0314] [Note 19]

[0315] The projection optical system according to Supplementary Note 18, wherein:

[0316] When the thickness of the prism along the optical axis is set to Dpr, and

[0317] When the refractive index of the prism with respect to the d-line is Npr,

[0318] The projection optical system satisfies the conditional formula (10) represented by the following formula:

[0319] 0.7<|DifP / (Dpr / Npr)|<1.8 (10).

[0320] [Note 20]

[0321] A projection display device comprises the projection optical system according to any one of Supplementary Notes 1 to 19.

Claims

1. A projection optical system that projects an image on a reduced side onto an enlarged side, wherein: The projection optical system does not include a reflective surface having optical power, The optical system includes a first optical system and a second optical system in order from the magnification side to the reduction side along the optical path, and an intermediate image is formed between the first optical system and the second optical system. The first optical system includes a light path deflecting surface for deflecting the light path. When the radius of the maximum effective image circle on the reduction side is set to Imax, The distance on the optical axis from the lens surface closest to the magnification side of the first optical system to the light path deflecting surface is Ddef, and When the projection optical system is a variable magnification optical system, when Ddef is set to a value at the wide-angle end, The projection optical system satisfies the conditional formula (1) represented by the following formula: 0.2 <Imax / Ddef<0.7 (1)。 2. The projection optical system according to claim 1, wherein: The first optical system includes, in order from the magnification side to the reduction side along the optical path, a front group having negative optical power, an optical path deflecting member including the optical path deflecting surface, and a rear group having positive optical power.

3. The projection optical system according to claim 2, wherein: The front group includes one or more positive lenses.

4. The projection optical system according to claim 2, wherein: The outermost periphery of the optically effective surface of the first optical system closest to the magnification side is located closer to the reduction side than an intersection of the optically effective surface and the optical axis in the optical axis direction.

5. The projection optical system according to claim 3, wherein: The average value of the Abbe numbers of all negative lenses included in the front group on the d-line basis is Vnave, and When the average value of the d-line-based Abbe numbers of all the positive lenses included in the front group is ν pave, the projection optical system satisfies the conditional formula (2) represented by the following formula: 10<v nave-v pave<40 (2).

6. The projection optical system according to claim 3, wherein: The average refractive index of all negative lenses included in the front group with respect to the d-line is Nnave, and When the average refractive index of all positive lenses included in the front group with respect to the d-line is Npave, The projection optical system satisfies the conditional formula (3) represented by the following formula: 0.15 <Npave-Nnave<0.45 (3)。 7. The projection optical system according to any one of claims 2 to 6, wherein: At least a portion of the rear group moves during focusing.

8. The projection optical system according to any one of claims 1 to 6, wherein: The second optical system includes two or more moving groups that move along the optical axis during magnification change.

9. The projection optical system according to claim 8, wherein: The moving group closest to the magnification side among the moving groups of the second optical system has positive refractive power.

10. The projection optical system according to any one of claims 2 to 6, wherein: The air conversion distance on the optical axis from the surface of the front group closest to the reduction side to the surface of the rear group closest to the magnification side is denoted as 1)fr, and When the projection optical system is a variable magnification optical system, when Dfr is set to a value at the wide-angle end, The projection optical system satisfies the conditional formula (4) represented by the following formula: 0.5 <Imax / Dfr<0.9 (4)。 11. The projection optical system according to any one of claims 2 to 6, wherein: The light path deflecting surface is a surface of a prism.

12. The projection optical system according to claim 11, wherein: When the thickness of the prism along the optical axis is set to Dpr, and When the refractive index of the prism with respect to the d-line is Npr, The projection optical system satisfies the conditional formula (5) represented by the following formula: 0.9 <Imax / (Dpt / Npr)<1.3 (5)。 13. The projection optical system according to any one of claims 1 to 6, wherein: When the maximum effective radius of the lens surface closest to the magnification side of the first optical system is ERf, and When the maximum value of the maximum effective radius of all lens surfaces of the projection optical system is set to FRmax, The projection optical system satisfies the conditional formula (6) represented by the following formula: 0 <ERf / ERmax<0.7 (6)。 14. The projection optical system according to any one of claims 1 to 6, wherein: The maximum value of the height of the axial marginal light rays from the optical axis on all lens surfaces of the first optical system is set to AH1, and When the maximum value of the height of the on-axis marginal rays from the optical axis on all lens surfaces of the second optical system is defined as AH2, The projection optical system satisfies the conditional formula (7) represented by the following formula: 0 <AH1 / AH2<0.7 (7)。 15. The projection optical system according to any one of claims 1 to 6, wherein: including an aperture stop on the reduction side closer to the intermediate image, The real image of the aperture stop exists inside the first optical system. When the position of the real image in the optical axis direction is set to a first position, and When a light ray emitted from an arbitrary point within the maximum effective image circle on the reduction side and passing through the center of the aperture stop toward the magnification side intersects the optical axis at a position closer to the magnification side than the intermediate image, the position farthest from the first position is set as the second position, The intersection point of the optical path deflecting surface and the optical axis is located within a range from the first position to the second position in the optical axis direction.

16. The projection optical system according to claim 15, wherein: Let k be a natural number from 1 to 10, A point on the maximum effective image circle on the reduced side whose height from the optical axis is k tenths of the radius of the maximum effective image circle is defined as point PHk. The position where the light emitted from the point PHk and passing through the center of the aperture stop toward the magnification side intersects the optical axis at a position closer to the magnification side than the intermediate image is defined as position Pk, The position Pk having the longest air-converted distance on the optical axis from the first position is set as the third position. The air conversion distance from the first position to the third position is DifP, In the sign of DifP, the distance on the reduction side is set as positive and the distance on the enlargement side is set as negative, based on the first position, and When the projection optical system is a variable magnification optical system, when DifP is set to a value at the wide-angle end, The projection optical system satisfies the conditional formula (8) represented by the following formula: -3<DifP / Imax<-0.2 (8).

17. The projection optical system according to claim 16, wherein: The first optical system includes a front group, an optical path deflecting component including the optical path deflecting surface, and a rear group in order from the magnification side to the reduction side along the optical path. The air conversion distance on the optical axis from the surface of the front group closest to the reduction side to the surface of the rear group closest to the magnification side is denoted as Dfr, and When the projection optical system is a variable magnification optical system, Dfr is set to a value at the wide-angle end. The projection optical system satisfies the conditional formula (9) represented by the following formula: 0.4<|DifP / Dfr|<0.7 (9).

18. The projection optical system according to claim 16 or 17, wherein: The light path deflecting surface is a surface of a prism.

19. The projection optical system according to claim 18, wherein: When the thickness of the prism along the optical axis is set to Dpr, and When the refractive index of the prism with respect to the d-line is Npr, The projection optical system satisfies the conditional formula (10) represented by the following formula: 0.7<|DifP / (Dpr / Npr)|<1.8 (10). 20 . A projection display device comprising the projection optical system according to claim 1 .

Images