Projection optical system and projector device

Abstract

Provided is a projection optical system and a projector device that enable further shortening of the focal length and miniaturization. The projection optical system is a projection optical system for enlarging and projecting an image or a video. The projection optical system includes a refractive section and a reflective section. The refractive section includes a plurality of lens groups. The reflective section includes a concave mirror that reflects light that has passed through the refractive section. The plurality of lens groups includes a focal group and at least one fixed group. The focal group is capable of changing the projection size of the image or the video. The focal group includes two lens groups. In the case of focusing, the two lens groups are moved along the optical axis by different displacement amounts. The lens located at the most magnification side among the plurality of lenses included in the refractive section, the second lens from the most magnification side, and the third lens from the most magnification side each have a negative refractive power.

Description

Technical Field

[0001] This application relates to projection optical systems and projector devices. Background Technology

[0002] A projector device magnifies and projects an image or video displayed in the image forming section of an image display element onto a projection surface (e.g., a screen). Hereinafter, the image or video magnified and projected onto the projection surface will be simply referred to as a "magnified image." Furthermore, examples of image display elements include liquid crystal panels and DMDs (Digital Micromirror Devices).

[0003] For example, in recent years, front-projection projectors that project magnified images onto a screen in front of the user have become widely used in businesses, schools, and homes. These projectors include a projection optics system. The projection optics system projects the image or picture formed by the image display element onto the projection surface in a magnified manner. In recent years, there has been a demand for further miniaturization and ultrashort focal length reduction in projection optics systems. However, to achieve ultrashort focal length reduction in projection optics, the number of lenses and / or lens groups in the refractive optics system included in the projection optics system increases. As a result, the overall length of the projection optics system becomes longer.

[0004] As a structure capable of short-focus projection optical systems, structures combining a refractive optical system and a reflector are known (Patent Documents 1-5, etc.). The refractive optical system consists of multiple lenses, and the reflector reflects light that has passed through the refractive optical system in the opposite direction. By combining the refractive optical system and the reflector, a short projection distance that is difficult to achieve with a refractive optical system alone can be realized.

[0005] The projection optical system disclosed in Patent Document 1 has a six-lens group structure. Moreover, this projection optical system has a reflective element.

[0006] Patent Document 2 discloses a projection optical system with a four-lens structure and two reflective elements. In this projection optical system, from the reduction side to the magnification side, a lens group with positive optical power, a lens group with positive optical power, a lens group with negative optical power, and a lens group with positive optical power are arranged sequentially.

[0007] Patent Document 3 discloses a projection optical system with a two-lens structure and a reflective element. In this projection optical system, a lens group with positive optical power and a lens group with negative optical power are arranged sequentially from the reduction side to the magnification side.

[0008] Patent Document 4 discloses a projection optical system with a four-lens group structure and a reflective element. In this projection optical system, from the reduction side to the magnification side, a lens group with positive optical power, a lens group with positive optical power, a lens group with positive optical power, and a lens group with negative optical power are arranged sequentially.

[0009] Patent Document 5 discloses a projection optical system with a three-lens structure and two reflective elements. In this projection optical system, from the reduction side to the magnification side, a lens group with positive optical power, a lens group with negative optical power, and a lens group with positive optical power are arranged sequentially.

[0010] Prior technology literature

[0011] [Patent Documents]

[0012] [Patent Document 1] Japanese Patent No. 6811636

[0013] [Patent Document 2] Japanese Patent No. 6497573

[0014] [Patent Document 3] Japanese Patent No. 5950000

[0015] [Patent Document 4] Japanese Patent Application Publication No. 2011-33737

[0016] [Patent Document 5] Japanese Patent No. 6252974 Summary of the Invention

[0017] The problem to be solved by the present invention

[0018] In the projection optical systems disclosed in Patent Documents 1-5, the overall length is not sufficiently short. Furthermore, the projection ratio (Throw Ratio (TR)) is not sufficiently small. In other words, the short focal length is insufficient.

[0019] This application is made to solve such problems, and its purpose is to provide a projection optical system and projector device that can achieve further short focal length reduction and miniaturization.

[0020] Solution for solving the problem

[0021] One aspect of this application provides a projection optical system for magnifying and projecting images or videos. This projection optical system includes a refractive section and a reflective section. The refractive section comprises multiple lens groups. The reflective section is composed of a concave mirror that reflects light transmitted through the refractive section. The multiple lens groups include a focal group and at least one fixed group, the focal group being movable when the projection size of the image or video changes. The focal group comprises two lens groups. During focusing, the two lens groups move along the optical axis with different displacements. The lens located on the magnification side, the second lens from the magnification side, and the third lens from the magnification side in the refractive section each have negative optical power.

[0022] Furthermore, another aspect of the projector device of this application includes the aforementioned projection optical system. The projection optical system further includes a light modulation element that modulates light from a light source to form image light. The image light passes through the projection optical system.

[0023] According to this application, a projection optical system and projector device capable of achieving further short focal length reduction and miniaturization can be provided. Attached Figure Description

[0024] Figure 1 It is a diagram showing the relationship between the projection optical system and the screen, and an example of a magnified view of the projection optical system.

[0025] Figure 2 This is a cross-sectional view schematically showing the structure of the projection optical system of Embodiment 1.

[0026] Figure 3 It is a diagram that schematically shows the positional relationship between the display element and the optical axis in a projection optical system.

[0027] Figure 4 This is a diagram illustrating an example of an image projected onto a flat screen during close-range projection (equivalent to approximately 80 inches) using the projection optics system of Embodiment 1.

[0028] Figure 5 This is a diagram illustrating an example of an image projected onto a flat screen during reference projection (equivalent to approximately 120 inches) based on the projection optics system of Embodiment 1.

[0029] Figure 6 This is a diagram illustrating an example of an image projected onto a flat screen during long-distance projection (equivalent to approximately 150 inches) using the projection optics system of Embodiment 1.

[0030] Figure 7This is a spot diagram showing a near-field projection (equivalent to approximately 80 inches) of the projection optical system based on Embodiment 1.

[0031] Figure 8 This is a diagram showing a dot plot of the reference projection (equivalent to approximately 120 inches) based on the projection optical system of Embodiment 1.

[0032] Figure 9 This is a dot plot showing a projection of the projection optical system LM1 based on Embodiment 1 at a distance (equivalent to about 150 inches).

[0033] Figure 10 It is a diagram showing the relationship between the projection optical system of Embodiment 2 and the screen, and an enlarged view of the projection optical system of Embodiment 2.

[0034] Figure 11 This is a cross-sectional view schematically showing the structure of the projection optical system of Embodiment 2.

[0035] Figure 12 This is a diagram illustrating an example of an image projected onto a flat screen at close range (approximately 100 inches) when projected using the projection optics system of Embodiment 2.

[0036] Figure 13 This is a diagram illustrating an example of an image projected onto a flat screen during reference projection (equivalent to approximately 125 inches) based on the projection optics system of Embodiment 2.

[0037] Figure 14 This is a diagram illustrating an example of an image projected onto a flat screen during long-distance projection (equivalent to approximately 150 inches) using the projection optics system of Embodiment 2.

[0038] Figure 15 This is a diagram showing a dot plot of the projection optical system based on Embodiment 2 at close range (equivalent to about 100 inches).

[0039] Figure 16 This is a diagram showing a dot plot of the reference projection (equivalent to approximately 125 inches) based on the projection optical system of Embodiment 2.

[0040] Figure 17 This is a dot plot showing a projection at a distance (equivalent to about 150 inches) based on the projection optics system of Embodiment 2.

[0041] Figure 18 It is a diagram showing the relationship between the projection optical system of Embodiment 3 and the screen, and an enlarged view of the projection optical system of Embodiment 3.

[0042] Figure 19This is a cross-sectional view schematically showing the structure of the projection optical system of Embodiment 3.

[0043] Figure 20 This is a diagram illustrating an example of an image projected onto a flat screen during close-range projection (equivalent to approximately 80 inches) using the projection optics system of Embodiment 3.

[0044] Figure 21 This is a diagram illustrating an example of an image projected onto a flat screen during reference projection (equivalent to approximately 125 inches) based on the projection optics system of Embodiment 3.

[0045] Figure 22 This is a diagram illustrating an example of an image projected onto a flat screen during long-distance projection (equivalent to approximately 150 inches) using the projection optics system of Embodiment 3.

[0046] Figure 23 This is a dot plot showing a near-distance projection (equivalent to about 80 inches) of the projection optical system based on Embodiment 3.

[0047] Figure 24 This is a diagram showing a dot plot of the reference projection (equivalent to approximately 125 inches) based on the projection optical system of Embodiment 3.

[0048] Figure 25 This is a dot plot showing a projection at a distance (equivalent to about 150 inches) based on the projection optics system of Embodiment 3.

[0049] Figure 26 It is a diagram showing the relationship between the projection optical system of Embodiment 4 and the screen, and an enlarged view of the projection optical system of Embodiment 4.

[0050] Figure 27 This is a cross-sectional view schematically showing the structure of the projection optical system of Embodiment 4.

[0051] Figure 28 This is a diagram illustrating an example of an image projected onto a flat screen at close range (approximately 100 inches) when projected using the projection optics system of Embodiment 4.

[0052] Figure 29 This is a diagram illustrating an example of an image projected onto a flat screen during reference projection (equivalent to approximately 125 inches) based on the projection optics system of Embodiment 4.

[0053] Figure 30 This is a diagram illustrating an example of an image projected onto a flat screen during long-distance projection (equivalent to approximately 150 inches) using the projection optics system of Embodiment 4.

[0054] Figure 31This is a diagram showing a dot plot of the projection optical system based on Embodiment 4 at close range (equivalent to about 100 inches).

[0055] Figure 32 This is a diagram showing a dot plot of the reference projection (equivalent to approximately 125 inches) based on the projection optics system of Embodiment 4.

[0056] Figure 33 This is a dot plot showing a projection at a distance (equivalent to about 150 inches) based on the projection optics system of Embodiment 4.

[0057] Figure 34 It is a diagram showing the relationship between the projection optical system of Embodiment 5 and the screen, and an enlarged view of the projection optical system of Embodiment 5.

[0058] Figure 35 This is a cross-sectional view schematically showing the structure of the projection optical system of Embodiment 5.

[0059] Figure 36 This is a diagram illustrating an example of an image projected onto a flat screen at close range (approximately 100 inches) when projected using the projection optics system of Embodiment 5.

[0060] Figure 37 This is a diagram illustrating an example of an image projected onto a flat screen during reference projection (equivalent to approximately 125 inches) based on the projection optics system of Embodiment 5.

[0061] Figure 38 This is a diagram illustrating an example of an image projected onto a flat screen during long-distance projection (equivalent to approximately 150 inches) using the projection optics system of Embodiment 5.

[0062] Figure 39 This is a diagram showing a dot plot of the projection optical system based on Embodiment 5 at close range (equivalent to about 100 inches).

[0063] Figure 40 This is a diagram showing a dot plot of the reference projection (equivalent to approximately 125 inches) based on the projection optical system of Embodiment 5.

[0064] Figure 41 This is a dot plot showing a projection at a distance (equivalent to about 150 inches) based on the projection optics system of Embodiment 5.

[0065] Figure 42 It is a diagram showing the relationship between the projection optical system of Embodiment 6 and the screen, and an enlarged view of the projection optical system of Embodiment 6.

[0066] Figure 43This is a cross-sectional view schematically showing the structure of the projection optical system of Embodiment 6.

[0067] Figure 44 This is a diagram illustrating an example of an image projected onto a flat screen at close range (equivalent to approximately 100 inches) when projected using the projection optics system of Embodiment 6.

[0068] Figure 45 This is a diagram illustrating an example of an image projected onto a flat screen during reference projection (equivalent to approximately 125 inches) based on the projection optics system of Embodiment 6.

[0069] Figure 46 This is a diagram illustrating an example of an image projected onto a flat screen during long-distance projection (equivalent to approximately 150 inches) using the projection optics system of Embodiment 6.

[0070] Figure 47 This is a diagram showing a dot plot when projecting at close range (equivalent to about 100 inches) using the projection optics system based on Embodiment 6.

[0071] Figure 48 This is a diagram showing a dot plot of the reference projection (equivalent to approximately 125 inches) based on the projection optics system of Embodiment 6.

[0072] Figure 49 This is a dot plot showing a projection at a distance (equivalent to about 150 inches) based on the projection optics system of Embodiment 6.

[0073] Figure 50 It is a diagram showing the relationship between the projection optical system of Embodiment 7 and the screen, and an enlarged view of the projection optical system of Embodiment 7.

[0074] Figure 51 This is a cross-sectional view schematically showing the structure of the projection optical system of Embodiment 7.

[0075] Figure 52 This is a diagram illustrating an example of an image projected onto a flat screen at close range (approximately 100 inches) when projected using the projection optics system of Embodiment 7.

[0076] Figure 53 This is a diagram illustrating an example of an image projected onto a flat screen during reference projection (equivalent to approximately 125 inches) based on the projection optics system of Embodiment 7.

[0077] Figure 54 This is a diagram illustrating an example of an image projected onto a flat screen during long-distance projection (equivalent to approximately 150 inches) using the projection optics system of Embodiment 7.

[0078] Figure 55 This is a diagram showing a dot plot of the projection optical system based on Embodiment 7 at close range (equivalent to about 100 inches).

[0079] Figure 56 This is a diagram showing a dot plot of the reference projection (equivalent to approximately 125 inches) based on the projection optical system of Embodiment 7.

[0080] Figure 57 This is a dot plot showing a projection at a distance (equivalent to about 150 inches) based on the projection optics system of Embodiment 7.

[0081] Figure 58 This is a schematic diagram illustrating an example of the cross-sectional structure of a projector assembly containing a projection optics system.

[0082] Explanation of reference numerals in the attached figures

[0083] 11 Projector unit, 12 Illumination system, 13, P1 Display element, 14, LM1 Projection optical system, 15 Dustproof glass, AX1 Optical axis, CG1 Cover glass, CG2 Optical components, D1 Aperture, G1 First lens group, G1-1 and G1-2 lens groups, G2 Second lens group, G3 Third lens group, G4 Fourth lens group, L1, L2, L3, L4, L5, L6, L7, L8, L9, L10, L11, L12, L13, L14, L15, L16, L17, L18, L19, L20, L21, and L22 Lenses, M1 Reflector, PR1 Prism, S1 Screen. Detailed Implementation

[0084] Hereinafter, a detailed description of one aspect of the embodiments of this application will be provided using the accompanying drawings. It should be noted that the objects in the drawings are appropriately omitted or exaggerated and depicted schematically for ease of understanding.

[0085] Figure 1 This is a diagram showing the relationship between the projection optical system LM1 and the screen S1 in this embodiment, and an enlarged view of an example of the projection optical system LM1. Figure 1 Above, an example is shown of the path of light emitted through display element P1 to reach screen S1. Furthermore, in Figure 1 Below, an enlarged view of an example of the projection optical system LM1 is shown.

[0086] Reference Figure 1Light emitted from display element P1 passes through multiple lens groups, is reflected at reflector M1, and reaches screen S1. This projects a magnified image onto screen S1. In projection optical system LM1, a beam of oblique light is used as the projection beam for imaging the magnified image onto screen S1. Because the light is reflected back at reflector M1, projection optical system LM1 can achieve a short focal point.

[0087] Figure 2 This is a cross-sectional view schematically showing the structure of the projection optical system LM1 of Embodiment 1. Figure 11 This is a cross-sectional view schematically showing the structure of the projection optical system LM1 in Embodiment 2. Figure 19 This is a cross-sectional view schematically showing the structure of the projection optical system LM1 in Embodiment 3. Figure 27 This is a cross-sectional view schematically showing the structure of the projection optical system LM1 in Embodiment 4. Figure 35 This is a cross-sectional view schematically showing the structure of the projection optical system LM1 in Embodiment 5. Figure 43 This is a cross-sectional view schematically showing the structure of the projection optical system LM1 of Embodiment 6. Figure 51 This is a cross-sectional view schematically showing the structure of the projection optical system LM1 in Embodiment 7. Figure 2 , Figure 11 , Figure 19 , Figure 27 , Figure 35 , Figure 43 and Figure 51 The structure of the projection optical system LM1 shown corresponds to the structure of the projection optical system in Examples 1-7 described later.

[0088] In respectively Figure 2 , Figure 11 , Figure 19 , Figure 27 , Figure 35 , Figure 43 and Figure 51 (Hereinafter referred to as "each structural diagram"), the left side of the diagram is the "reduction side," and the right side is the "enlargement side." To avoid complexity, the symbols are common across the structural diagrams. For example, in each structural diagram, the symbol Gi represents the i-th lens group counted from the reduction side, and the symbol Lj represents the j-th lens counted from the reduction side.

[0089] Referring to the structural diagrams, the projection optical system LM1 includes multiple lens groups, display element P1, cover glass CG1, prism PR1, optical components CG2, aperture D1, and reflector M1.

[0090] Display element P1 displays an image or video (hereinafter also referred to as "image, etc."). Display element P1 is, for example, composed of a liquid crystal panel or a DMD. Cover glass CG1 is mounted on display element P1. Prism PR1 is, for example, composed of a TIR (Total Internal Reflection) prism and is disposed between cover glass CG1 and optical element CG2. Optical element CG2 is disposed between prism PR1 and lens L1. Reflector M1 is, for example, composed of a concave mirror. Reflector M1 is disposed at a position closer to the magnification side than the lens located on the magnification side among the multiple lenses included in projection optical system LM1. Reflector M1 reflects light that has passed through the multiple lens groups.

[0091] Figure 2 , Figure 11 and Figure 19 The projection optical systems LM1 shown are four-lens groups. In these projection optical systems LM1, from the reduction side to the magnification side, the first lens group G1, the second lens group G2, the third lens group G3, and the fourth lens group G4 are arranged sequentially. That is, the first lens group G1, the second lens group G2, the third lens group G3, and the fourth lens group G4 constitute the "refracting section".

[0092] in addition, Figure 27 , Figure 35 , Figure 43 and Figure 51 The projection optical systems LM1 shown are three-lens structures. In these projection optical systems LM1, the first lens group G1, the second lens group G2, and the third lens group G3 are arranged sequentially from the reduction side to the magnification side. That is, the first lens group G1, the second lens group G2, and the third lens group G3 constitute the "refracting section".

[0093] Aperture D1 is an open aperture. In the projection optical system LM1 shown in the various structural diagrams, aperture D1 is disposed within the first lens group G1. Since aperture D1 is disposed within the first lens group G1 closest to the narrowing side, the outer diameter of each lens contained in the first lens group G1 can be reduced.

[0094] The arrows shown in the structural diagrams indicate the direction of displacement of the i-th lens group Gi when adjusting the focus from the near-distance side to the far-distance side. Figure 2 , Figure 11 and Figure 19 In the projection optical system LM1 shown, the first lens group G1, the fourth lens group G4, and the reflector M1 are fixed. On the other hand, the second lens group G2 and the third lens group G3 move along the optical axis. When focusing from the near distance side to the far distance side, the second lens group G2 and the third lens group G3 move along the optical axis with different displacements in the direction from the reduction side to the magnification side.

[0095] In addition, Figure 27 , Figure 35 , Figure 43 and Figure 51 In the projection optical system LM1 shown, the first lens group G1 and the reflector M1 are fixed. On the other hand, the second lens group G2 and the third lens group G3 move along the optical axis. When focusing from the near distance side to the far distance side, the second lens group G2 and the third lens group G3 move along the optical axis with different displacements in the direction from the magnification side to the reduction side.

[0096] In addition, the optical power of each lens group is as described below. Figure 2 , Figure 11 and Figure 19 In the projection optical system LM1 shown, the first lens group G1 has positive optical power, the second lens group G2 has positive optical power, the third lens group G3 has negative optical power, and the fourth lens group G4 has negative optical power. Furthermore, in Figure 27 , Figure 35 , Figure 43 and Figure 51 In the projection optical system LM1 shown in each diagram, the first lens group G1 has positive optical power, the second lens group G2 has positive optical power, and the third lens group G3 has negative optical power. Thus, in the projection optical system LM1 shown in each structural diagram, the lens group located on the side closest to the magnification has negative optical power.

[0097] In the projection optical system LM1 shown in the various structural diagrams, the third lens group G3 is a negative lens group, which further reduces the height of the principal ray and decreases the effective diameter of the lens. As a result, the miniaturization of the projection optical system LM1 can be achieved. During the projection of images, the beam diameter of the imaging beam converges at the first lens group G1 and the second lens group G2, and then diverges due to the negative optical power of the third lens group G3.

[0098] Furthermore, the projection optical system LM1 shown in each structural diagram is telecentric. In the case of a telecentric optical system, a beam of light with a constant angular direction is emitted from the display element P1, which can suppress the difference in brightness between the center and the periphery of the image with respect to the light emitted from the projection system.

[0099] The projection optical system LM1 shown in each structural diagram preferably satisfies one or more of the following conditions (1)-(8).

[0100] (1)-2.5 <FN / FP<0.0

[0101] (2) 0.1 < |FoN / FoP| < 1.0

[0102] (3) 0.9 <LW1 / LW2<6.0

[0103] (4)-1.5 <LW3 / LW4<0.0

[0104] (5)7 <F1 / F<15

[0105] (6) 0.1 <F1-1 / F1-2<1.2

[0106] (7)|Ds / W|≤0.22

[0107] (8) 75° < θM

[0108] It should be noted that "FP" represents the focal length of the focal group with positive optical power (second lens group G2), and "FN" represents the focal length of the focal group with negative optical power (third lens group G3). "FoP" represents the amount of movement of the lens group with positive optical power (second lens group G2) when focusing from the near side to the far side, and "FoN" represents the amount of movement of the lens group with negative optical power (third lens group G3) when focusing from the near side to the far side.

[0109] "LW1" represents the focal length of the lens located on the magnification side among the multiple lenses included in the projection optical system LM1; "LW2" represents the focal length of the second lens from the magnification side among the multiple lenses included in the projection optical system LM1; "LW3" represents the focal length of the third lens from the magnification side among the multiple lenses included in the projection optical system LM1; and "LW4" represents the focal length of the fourth lens from the magnification side among the multiple lenses included in the projection optical system LM1.

[0110] “F” represents the focal length of the entire projection optical system LM1, and “F1” represents the focal length of the lens group closest to the reduction side (first lens group G1). “F1-1” represents the focal length of the system from the lens closest to the reduction side (lens L1) in the first lens group G1 to the system of aperture D1 (lens group G1-1), and “F1-2” represents the focal length of the system of the system from aperture D1 to the lens closest to the magnification side in the first lens group G1 (lens group G1-2). “Ds” represents the distance from the reflector M1 to the screen S1, and “W” represents the horizontal length of the magnified image. “θM” represents the maximum angle of incidence towards the screen S1.

[0111] The projection optical system LM1 shown in the structural diagrams is a projection optical system for magnifying and projecting images or videos. The projection optical system LM1 includes a refractive section and a reflective section M1. The refractive section includes multiple lens groups (e.g., a first lens group G1, a second lens group G2, a third lens group G3, and a fourth lens group G4, or a first lens group G1, a second lens group G2, and a third lens group G3). The reflective section M1 is composed of a concave mirror that reflects light transmitted through the refractive section. The multiple lens groups include a focal group that can move when the projected size of the image or video changes, and at least one fixed group. The focal group includes two lens groups (e.g., a second lens group G2 and a third lens group G3). In the case of focusing, the two lens groups move along the optical axis with different displacements. The lens located on the magnification side, the second lens from the magnification side, and the third lens from the magnification side in the refractive section each have negative optical power. The inventors have discovered that this allows for further shortening and miniaturization of the projection optical system LM1. Details are described in the embodiments described later.

[0112] The projection optical system LM1 shown in each structural diagram preferably satisfies the above condition (1). Condition (1) is related to the optical performance of focusing. Condition (1) is the condition for the magnification allocation as a focus group. If condition (1) is not satisfied, the image projected onto the screen S1 is affected. When FN / FP becomes below the lower limit of condition (1), the magnification allocation as a focus group becomes disordered. As a result, coma aberration and distortion aberration are affected when the size of the magnified image is changed. Therefore, it is preferable to satisfy condition (1).

[0113] Condition (2) is related to the amount of movement of each focus group during focusing. If |FoN / FoP| is above the upper limit of condition (2) or below the lower limit of condition (2), the balance during focusing is disordered. As a result, the optical performance on both the near and far sides is affected, and therefore is not preferred.

[0114] Condition (3) is related to distortion aberration. If LW1 / LW2 is below the lower limit of condition (3), distortion aberration on the far side is more likely to be affected. If LW / LW2 is above the upper limit of condition (3), distortion aberration on the near side is more likely to be affected. Therefore, this condition is not preferred.

[0115] Condition (4) is related to coma. If LW3 / LW4 is below the lower limit of condition (4), coma is more likely to be affected on the far side, so it is not preferred.

[0116] Condition (5) is a condition for achieving short focal length and high performance. In the projection optical system LM1, the first lens group G1 plays a role in correcting various optical aberrations. If F1 / F is above the upper limit of condition (5), a wider field of view can be achieved, but there is a tendency for coma aberration to increase. Moreover, if F1 / F is below the lower limit of condition (5), there is a tendency for the focal length of the optical system to become longer. As a result, there is a tendency for the optical performance to become better, but there is a tendency for the overall optical system to become larger. Therefore, this is not preferred.

[0117] Condition (6) is related to the magnification distribution between lens group G1-1 and lens group G1-2. If F1-1 / F1-2 is above the upper limit of condition (6) or below the lower limit of condition (6), the magnification distribution within the first lens group G1 is disordered, thus affecting coma aberration and distortion aberration, etc. Therefore, it is not preferred.

[0118] Condition (7) is related to the projection size and the distance to the screen. Condition (7) indicates that the projection optical system LM1 has a short focal point. If condition (7) is not met, there is a tendency for the size of the magnified image to decrease or the projection distance to increase.

[0119] Condition (8) is related to the maximum angle of incidence toward screen S1. Condition (8) indicates that the maximum angle of incidence of the light emitted from the projection optical system LM1 relative to screen S1 is greater than 75°.

[0120] in addition, Figure 2 , Figure 11 and Figure 19 The projection optical system LM1 shown can satisfy one or more of the following conditions (9)-(12).

[0121] (9) Dl-m / OALl-m<0.48

[0122] (10)-1.0 <F2 / F3<-0.4

[0123] (11)7 <F1 / F<10

[0124] (12)1.0 <F3 / F4<2.0

[0125] It should be noted that "Dl-m" represents the distance from the surface of the refracting component closest to the reflecting part M1 to the reflecting part M1 in the projection optical system LM1, and "OALl-m" represents the distance from the surface of the refracting component closest to the reducing side to the reflecting part M1 in the projection optical system LM1. "F2" represents the focal length of the second lens group G2, "F3" represents the focal length of the third lens group G3, and "F4" represents the focal length of the fourth lens group G4.

[0126] Figure 2 , Figure 11 and Figure 19 The projection optical system LM1 shown is a projection optical system for magnifying and projecting images or videos. The projection optical system LM1 includes: a refractive section having multiple lens groups; and a reflective section. The multiple lens groups include four lens groups, including a focal group that can move when the projected size of the image or video changes, and a fixed group that remains fixed when the projected size of the image or video changes. The reflective section is composed of a concave mirror that reflects light. The projection optical system LM1 satisfies the above condition (9).

[0127] Condition (9) is related to the size of the projection system. If condition (9) is not met, there is a tendency for the overall length of the projection optical system LM1 to become longer. By satisfying condition (9), a wide field of view and a small projection system can be achieved. Therefore, satisfying condition (9) is preferred for the high performance of the projection optical system LM1.

[0128] Condition (10) is the condition for the magnification allocation of the focus group. If condition (10) is not met, the image projected onto screen S1 is affected. If F2 / F3 falls below the lower limit of condition (10), the magnification allocation of the focus group becomes disordered. As a result, coma and distortion aberrations are affected when the size of the magnified image is changed. Therefore, it is preferable to satisfy condition (10).

[0129] Condition (11) is a condition for achieving short focal length and high performance. In the projection optical system LM1, the first lens group G1 plays a role in correcting various optical aberrations. If F1 / F is above the upper limit of condition (11), a wider field of view can be achieved, but there is a tendency for coma aberration to increase. Moreover, if F1 / F is below the lower limit of condition (11), there is a tendency for the focal length of the optical system as a whole to increase. As a result, there is a tendency for the optical performance to become better, but there is a tendency for the overall optical system to become larger. Therefore, this is not preferred.

[0130] Condition (12) specifies the preferred magnification distribution between the third lens group G3 and the fourth lens group G4. If condition (12) is not met, it affects the movement of the lens groups and distortion aberrations. If F3 / F4 is below the lower limit of condition (12), the negative magnification of the third lens group G3 decreases, or the negative magnification of the fourth lens group G4 increases. Therefore, there is a tendency for the movement of the third lens group G3 to increase, and this affects distortion aberration correction. If F3 / F4 is above the upper limit of condition (12), the negative magnification of the third lens group G3 increases, or the negative magnification of the fourth lens group G4 decreases. Therefore, the movement of the third lens group G3 decreases, but there is a tendency for the fourth lens group G4 to increase. This is therefore not preferred.

[0131] Figure 58 This is a schematic cross-sectional view of an example of a projector assembly 11 including the projection optical system LM1. (Refer to...) Figure 58 The projector assembly 11 includes an illumination system 12, a display element 13, a projection optics system 14, and a dustproof glass 15. As the projection optics system 14, for example, [missing information - likely a specific type of glass] is used. Figure 2 , Figure 11 , Figure 19 , Figure 27 , Figure 35 , Figure 43 and Figure 51 LM1 is one of the projection optical systems shown in the diagram.

[0132] The illumination system 12 illuminates the display element 13 with light of three colors, consisting of RGB, separated in time. The timing of illuminating each color of light is controlled, for example, by adjusting the tilt of the micromirrors constituting the DMD. Thus, an image to be projected is displayed on the display element 13. Light (image light) whose intensity has been modulated by the image displayed on the display element 13 (an example of a "light modulation element") passes through the projection optics system 14, and is projected onto the screen, for example, as a magnified image.

[0133] The lighting system 12 includes, for example, a condenser lens and a reflector in addition to the light source. Therefore, the space required to accommodate the lighting system 12 tends to increase. Furthermore, in the projection optical system 14, since prisms are arranged between the display element 13 and multiple lens groups, it is necessary to ensure the back focus of the projection optical system 14 to a certain extent. Moreover, a dustproof glass 15 is provided to prevent dust or dirt from entering the projector unit 11. The dustproof glass 15 is, for example, made of flat glass.

[0134] In the projection optical system 14, during zooming from the near side to the far side, the second lens group G2 with positive optical power and the third lens group G3 with negative optical power move along the optical axis from the reduced side to the magnified side or from the magnified side to the reduced side with different displacements.

[0135] As described above, the projection optical system LM1 of this embodiment is a projection optical system for magnifying and projecting images or videos. The projection optical system LM1 includes a refractive section and a reflective section M1. The refractive section includes multiple lens groups (e.g., a first lens group G1, a second lens group G2, a third lens group G3, and a fourth lens group G4, or a first lens group G1, a second lens group G2, and a third lens group G3). The reflective section M1 is composed of a concave mirror that reflects light transmitted through the refractive section. The multiple lens groups include a focal group that can move when the projection size of the image or video changes, and at least one fixed group. The focal group includes two lens groups (e.g., a second lens group G2 and a third lens group G3). In the case of focusing, the two lens groups move along the optical axis with different displacements. The lens located on the magnification side, the second lens from the magnification side, and the third lens from the magnification side among the multiple lenses included in the refractive section each have negative optical power. This enables further shortening and miniaturization of the projection optical system LM1.

[0136] The embodiments of this application have been illustrated above. Specifically, detailed descriptions and drawings have been provided for illustrative purposes. Therefore, the constituent elements described in the detailed descriptions and drawings sometimes include elements that are not essential for solving the problem. Thus, although these non-essential constituent elements are described in the detailed descriptions and drawings, they should not be directly considered as essential.

[0137] Furthermore, the above embodiments are merely illustrative examples of this application at all points. Various modifications and alterations can be made to the above embodiments within the scope of this application. That is, in the implementation of this application, specific structures can be appropriately adopted according to the embodiments.

[0138] Furthermore, in the embodiments described below, the DMD is conceived as a display element, but the display element is not limited to a DMD. Also, in the embodiments described below, the "lens group with a positive refractive index" constituting the lens group of the projection optical system is also referred to as the "positive group," and the "lens group with a negative optical power" constituting the lens group of the projection optical system is also referred to as the "negative group." Moreover, a "biconvex lens" is one type of positive lens, and a "biconcave lens" is one type of negative lens.

[0139]

Example

[0140] Specific embodiments 1-7 of the projection optical system of the present invention will be described below. First, the common aspects in embodiments 1-7 will be explained. The meanings of the various symbols in each embodiment are as follows.

[0141] F: Focal length of the entire optical system

[0142] f: Focal length of the lens

[0143] fg: Focal length of the lens group

[0144] fg2: Focal length of each lens group before and after aperture D1 in the first lens group G1.

[0145] NA: Number of openings

[0146] R: Radius of curvature (or paraxial radius of curvature in the case of aspherical lenses)

[0147] D: Surface spacing

[0148] Nd: Refractive index relative to the d-line

[0149] vd: Abbe number of the d-line

[0150] Furthermore, aspherical surfaces are represented by the well-known formula (A1).

[0151] X=(H^2 / R) / [1+{1-K(H / r)2}^(1 / 2)]+c4·H^4+c6·H^6+c8·H^8+c10·H^10+……(A1)

[0152] In the above formula (A1), X represents "the displacement in the direction of the optical axis at a position at a height H from the optical axis with the vertex of the face as the reference", K represents "conic coefficient", and c4, c6, c8, c10... represent "aspheric coefficients" respectively.

[0153] <Example 1>

[0154] The structure of the projection optical system in Example 1 is as follows: Figure 2 As shown. Moreover, in Figure 1 The diagram illustrates the relationship between the optical path of the projection optical system LM1 in Embodiment 1 and the screen S1. For example... Figure 1 As shown, in the projection optical system LM1, light is reflected back through the reflector M1, thereby achieving short focal length.

[0155] like Figure 2 As shown, the projection optical system LM1 includes a first lens group G1, a second lens group G2, a third lens group G3, and a fourth lens group G4.

[0156] The first lens group G1 includes lenses L1-L10. In the first lens group G1, lenses L1-L10 are arranged sequentially from the narrowing side. The second lens group G2 includes lenses L11-L13. In the second lens group G2, lenses L11-L13 are arranged sequentially from the narrowing side.

[0157] The third lens group G3 includes lenses L14-L16. In the third lens group G3, lenses L14-L16 are arranged sequentially from the reduced side. The fourth lens group G4 is composed of lens L17. The reflecting part M1 is composed of a concave mirror. The reflecting part M1 is located below the optical axis AX1.

[0158] In the projection optical system LM1, an image is displayed on the left-hand side of the cover glass CG1 mounted on the display element P1. Prism PR1 and optical component CG2 are respectively positioned between the display element P1 and lens L1.

[0159] When focusing from the near distance side to the far distance side, the second lens group G2, which has positive optical power, and the third lens group G3, which has negative optical power, move from the reduced side to the magnified side, respectively.

[0160] The first lens group G1 is the positive group, as described above, including lenses L1-L10. Lens L1 is a Meniscus lens that convexes towards the reduction side. Lens L2 is a biconvex positive lens. Lens L3 is a biconvex positive lens. Lens L4 is a negative Meniscus lens that is concave towards the reduction side. Lens L5 is a biconvex positive lens. Lens L6 is a biconcave negative lens. Lens L7 is a Meniscus lens that convexes towards the reduction side. Lens L8 is a biconvex positive lens. Lens L9 is a Meniscus lens that convexes towards the magnification side. Lens L10 is a biconcave negative lens.

[0161] Two lenses are formed by lenses L3 and L4. Three lenses are formed by lenses L5-L7. Two lenses are formed by lenses L9 and L10. Furthermore, both surfaces of lens L2 are aspherical.

[0162] Aperture D1 is positioned within the first lens group G1, between lenses L7 and L8. That is, aperture D1 is located within the first lens group G1. Aperture D1 and the first lens group G1 are fixed together.

[0163] Furthermore, the first lens group G1 includes lens groups G1-1 and G1-2. Lens group G1-1 is composed of lenses located in the region from the narrowest side to the aperture D1 among the multiple lenses included in the first lens group G1. Specifically, lens group G1-1 includes lenses L1-L7. Lens group G1-2 is composed of lenses located in the region from the aperture D1 to the magnifying side among the multiple lenses included in the first lens group G1. Specifically, lens group G1-2 includes lenses L8-L10.

[0164] The second lens group G2 is a positive group, as described above, including lenses L11-L13. Lens L11 is a biconvex positive lens. Lens L12 is a biconcave negative lens. Lens L13 is a biconvex positive lens. Furthermore, both surfaces of lens L11 are aspherical.

[0165] The third lens group G3 is a negative group, as described above, including lenses L14-L16. Lens L14 is a positive convex-concave lens that bulges towards the reduction side. Lens L15 is a biconcave negative lens. Lens L16 is a biconcave negative convex-concave lens with a small thickness ratio, where the peripheral portion of the lens is bent towards the reduction side. Furthermore, both surfaces of lens L16 are aspherical.

[0166] The fourth lens group, G4, is a negative group, as described above, and includes lens L17. Lens L17 is a biconcave negative lens.

[0167] In Example 1, the focal length (F), number of apertures (NA), and maximum incident angle (θM) of the entire projection optical system LM1 are as follows.

[0168] F = 1.9mm

[0169] NA = 0.23

[0170] θM=78°

[0171] The data (RDN) of the projection optical system LM1 in Example 1 are shown in Table 1 below.

[0172] Table 1

[0173]

[0174] In Table 1, the lens surfaces marked with an asterisk (*) are aspherical. Specifically, surfaces 10, 11, 25, 26, 35, 36, and 39, marked with an asterisk, are aspherical. The parameters of each aspherical surface in equation (A1) are shown in Table 2 below.

[0175] Table 2

[0176] K -1.782 -94.028 -4.503 17.666 4.256 -31.235 -3.762 C4 -1.63863E-05 1.15457E-05 1.24280E-05 -2.34499E-06 -1.34474E-06 -4.24941E-05 -4.60988E-06 C6 -2.80601E-08 -7.90482E-09 2.44122E-08 -3.46444E-08 3.35112E-08 3.76767E-08 2.90629E-09 C8 1.52881E-11 -7.54032E-11 1.98789E-10 3.35513E-10 -6.72459E-11 4.58370E-12 -1.67568E-12 C10 4.46415E-13 1.30739E-12 -8.82034E-13 -9.75581E-13 0.00000E+00 -7.48874E-14 6.59545E-16 C12 3.89666E-15 1.83688E-15 -1.03079E-16 4.93151E-15 0.00000E+00 2.60289E-17 -1.67128E-19 C14 8.71043E-18 1.56081E-18 -4.10083E-18 -4.64533E-18 0.00000E+00 2.78608E-20 2.40332E-23 C16 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 -4.37216E-23 -1.51673E-27

[0177] Regarding D (interval) in Table 1, for surfaces marked with "S", displacement is achieved through focusing. During focusing, "S24" between the first lens group G1 and the second lens group G2, "S30" between the second lens group G2 and the third lens group G3, and "S36" between the third lens group G3 and the fourth lens group G4 are displaced respectively. Furthermore, the displacement between the reflector M1 and the screen surface is "S39". Since light is reflected, S39 is set to negative (-). Table 3 below shows how S24, S30, S36, and S39 are displaced. It should be noted that the distances to the screen are selected as close (approximately 80 inches), reference (approximately 120 inches), and far (approximately 150 inches) as references.

[0178] Table 3

[0179] close up 5.786 8.131 3.601 -346.674 benchmark 6.083 8.789 2.646 -513.346 long distance 6.205 9.013 2.3 -638.35

[0180] Furthermore, in the projection optical system LM1 of Embodiment 1, the horizontal and vertical dimensions of the display element P1 located on the side closest to the reduction are shown in Table 4 below.

[0181] Table 4

[0182] Longitudinal length 5.82mm Distance from the optical axis to the bottom edge of the display panel 1.313mm

[0183] Figure 3 This diagram schematically illustrates the positional relationship between the display element P1 and the optical axis AX1 in the projection optical system LM1. Figure 3 The image shows the state of display element P1 as viewed from a magnified perspective. Figure 3 In the diagram, the horizontal length of display element P1 is represented by "H", and the vertical length of display element P1 is represented by "V". Furthermore, the distance from the optical axis AX1 to the lower end of display element P1 is represented by "y".

[0184] Figure 4 This is a diagram illustrating an example of an image projected onto a flat screen during close-range projection (equivalent to approximately 80 inches) using the projection optics system LM1 based on Embodiment 1. Figure 5 This is a diagram illustrating an example of an image projected onto a flat screen during reference projection (equivalent to approximately 120 inches) using the projection optical system LM1 based on Embodiment 1. Figure 6 This is a diagram illustrating an example of an image projected onto a flat screen during a long-distance projection (equivalent to approximately 150 inches) using the projection optics system LM1 based on Embodiment 1. Figure 4 , Figure 5 and Figure 6The simulation results of grid distortion on the screens at near distance (approximately 80 inches), reference distance (approximately 120 inches), and far distance (approximately 150 inches) are shown respectively. Figure 4 , Figure 5 and Figure 6 As shown, good corrections were performed in the projection optical system LM1 of Example 1.

[0185] Furthermore, in the projection optical system LM1 of Embodiment 1, the X and Y coordinates of the display element P1 are specified as shown in Table 5 below. It should be noted that, since it is symmetrical about the X-axis, the coordinates are specified only on one side.

[0186] Table 5

[0187] F1 -5.184 7.145 F2 -2.592 7.145 F3 0 7.145 F4 -5.184 5.687 F5 -2.592 5.687 F6 0 5.687 F7 -5.184 4.229 F8 -2.592 4.229 F9 0 4.229 F10 -5.184 2.771 F11 -2.592 2.771 F12 0 2.771 F13 -5.184 1.313 F14 -2.592 1.313 F15 0 1.313

[0188] Figure 7 This is a dot plot showing a near-field projection (equivalent to about 80 inches) of the projection optical system LM1 based on Embodiment 1. Figure 8 This is a dot plot showing the reference projection (equivalent to about 120 inches) of the projection optical system LM1 based on Embodiment 1. Figure 9 This is a dot plot showing the projection distance (approximately 150 inches) of the projection optical system LM1 based on Embodiment 1. These dot plots were simulated under the conditions shown in Table 5 above. Figure 7 , Figure 8 and Figure 9 As shown, good corrections were performed in the projection optical system LM1 of Example 1.

[0189] Furthermore, the parameters of the projection optical system LM1 in Embodiment 1 are shown in Table 6 below. It should be noted that "OAL" represents the total length of the projection optical system LM1 from the display element P1 to the reflector M1. Moreover, the other parameters are as described in the above embodiments, and this is also true in Embodiments 2-7 described later.

[0190] Table 6

[0191]

[0192] In the projection optical system LM1 of Embodiment 1, the values ​​of conditions (1)-(8) above are shown in Table 7 below. That is, in the projection optical system LM1 of Embodiment 1, conditions (1)-(8) above are satisfied respectively.

[0193] Table 7

[0194]

[0195] Alternatively, from another perspective, the parameters of the projection optical system LM1 in Embodiment 1 are shown in Table 8 below.

[0196] Table 8

[0197]

[0198] In the projection optical system LM1 of Embodiment 1, the values ​​of the above conditions (9)-(12) are shown in Table 9 below. That is, in the projection optical system LM1 of Embodiment 1, the above conditions (9)-(12) are satisfied respectively.

[0199] Table 9

[0200]

[0201] As described above, the projection optical system LM1 in Embodiment 1 is as follows: Figures 4-9 The sample has good optical properties and satisfies conditions (1)-(12).

[0202] <Example 2>

[0203] The structure of the projection optical system in Example 2 is as follows: Figure 11 As shown. Moreover, Figure 10 This is a diagram showing the relationship between the projection optical system LM1 and the screen S1 in Embodiment 2, and an enlarged view of the projection optical system LM1 in Embodiment 2. Figure 10 For example, the relationship between the optical path of the projection optical system LM1 and the screen S1 in Embodiment 2 is shown. Figure 10 As shown, in the projection optical system LM1, the light is reflected back by the reflector M1, thereby achieving short focal length.

[0204] like Figure 11 As shown, the projection optical system LM1 includes a first lens group G1, a second lens group G2, a third lens group G3, and a fourth lens group G4.

[0205] The first lens group G1 includes lenses L1-L10. In the first lens group G1, lenses L1-L10 are arranged sequentially from the narrowing side. The second lens group G2 includes lenses L11-L13. In the second lens group G2, lenses L11-L13 are arranged sequentially from the narrowing side.

[0206] The third lens group G3 includes lenses L14-L16. In the third lens group G3, lenses L14-L16 are arranged sequentially from the reduced side. The fourth lens group G4 is composed of lens L17. The reflecting part M1 is composed of a concave mirror. The reflecting part M1 is located below the optical axis AX1.

[0207] In the projection optical system LM1, an image is displayed on the left-hand side of the cover glass CG1 mounted on the display element P1. Prism PR1 and optical component CG2 are respectively positioned between the display element P1 and lens L1.

[0208] When focusing from the near side to the far side, the second lens group G2 and the third lens group G3 move from the reduced side to the magnified side, respectively.

[0209] The first lens group G1 is the positive group, as described above, and includes lenses L1-L10. Lens L1 is a positive convex-concave lens that convex towards the reduction side. Lens L2 is a biconvex positive lens. Lens L3 is a biconvex positive lens. Lens L4 is a negative convex-concave lens that is concave towards the reduction side. Lens L5 is a biconvex positive lens. Lens L6 is a biconcave negative lens. Lens L7 is a positive convex-concave lens that convex towards the reduction side. Lens L8 is a biconvex positive lens. Lens L9 is a positive convex-concave lens that convex towards the magnification side. Lens L10 is a biconcave negative lens.

[0210] Two lenses are formed by lenses L3 and L4. Three lenses are formed by lenses L5-L7. Two lenses are formed by lenses L9 and L10. Furthermore, both surfaces of lens L2 are aspherical.

[0211] Aperture D1 is positioned within the first lens group G1, between lenses L7 and L8. That is, aperture D1 is located within the first lens group G1. Aperture D1 and the first lens group G1 are fixed together.

[0212] Furthermore, the first lens group G1 includes lens groups G1-1 and G1-2. Lens group G1-1 is composed of lenses located in the region from the narrowest side to the aperture D1 among the multiple lenses included in the first lens group G1. Specifically, lens group G1-1 includes lenses L1-L7. Lens group G1-2 is composed of lenses located in the region from the aperture D1 to the magnifying side among the multiple lenses included in the first lens group G1. Specifically, lens group G1-2 includes lenses L8-L10.

[0213] The second lens group G2 is a positive group, as described above, and includes lenses L11-L13. Lens L11 is a biconvex positive lens. Lens L12 is a biconcave negative lens. Lens L13 is a biconvex positive lens. Furthermore, both surfaces of lens L11 are aspherical.

[0214] The third lens group G3 is the negative group, as described above, and includes lenses L14-L16. Lens L14 is a positive convex-concave lens that bulges towards the narrowing side. Lens L15 is a biconcave negative lens. Lens L16 is a biconcave negative convex-concave lens with a small thickness ratio, and its peripheral portion bends towards the narrowing side. Furthermore, both surfaces of lens L16 are aspherical.

[0215] The fourth lens group, G4, is a negative group, as described above, and includes lens L17. Lens L17 is a biconcave negative lens.

[0216] In Example 2, the focal length (F), number of apertures (NA), and maximum incident angle (θM) of the entire projection optical system LM1 are as follows.

[0217] F = 1.9mm

[0218] NA = 0.23

[0219] θM=78°

[0220] The data (RDN) of the projection optical system LM1 in Example 2 are shown in Table 10 below.

[0221] Table 10

[0222]

[0223] In Table 10, the lens surfaces with an asterisk (*) in the number column are aspherical. That is, the 10th, 11th, 25th, 26th, 35th, 36th, and 39th surfaces marked with an asterisk are aspherical. The parameters of each aspherical surface in the above formula (A1) are shown in Table 11 below.

[0224] Table 11

[0225] K -1.678 -62.691 -9.894 20.593 2.465 -26.07 -3.667 C4 -1.49220E-05 7.17372E-06 -1.48392E-05 -9.52969E-06 -2.09691E-06 -3.90742E-05 -4.51732E-06 C6 -9.23162E-09 -6.74689E-09 2.34502E-08 -3.03554E-08 3.93557E-08 2.97436E-08 2.86207E-09 C8 -1.08218E-10 -1.05245E-10 6.10015E-11 3.69731E-10 -645810E-11 1.56333E-11 -1.66994E-12 C10 -5.15388E-14 -2.14913E-13 -1.31770E-12 -1.47550E-12 0.00000E+00 -6.01001E-14 6.61121E-16 C12 0 0 0 0 0 9.95416E-18 -1.67266E-19 C14 0 0 0 0 0 0.00000E+00 2.38629E-23 C16 0 0 0 0 0 0.00000E+00 -1.48699E-27

[0226] Regarding D (interval) in Table 10, for surfaces marked with "S", displacement is achieved through focusing. During focusing, "S24" between the first lens group G1 and the second lens group G2, "S30" between the second lens group G2 and the third lens group G3, and "S36" between the third lens group G3 and the fourth lens group G4 are displaced respectively. Furthermore, the displacement between the reflector M1 and the screen surface is "S39". Since light is reflected, S39 is set to negative (-). Table 12 below shows how S24, S30, S36, and S39 are displaced. It should be noted that the distances to the screen are selected as close (approximately 100 inches), reference (approximately 125 inches), and far (approximately 150 inches) as references.

[0227] Table 12

[0228] close up 6.041 1.1 2.573 -430 benchmark 6.198 1.377 2.138 -534.4 long distance 6.299 1.549 1.866 -638.8

[0229] Furthermore, in the projection optical system LM1 of Embodiment 2, the horizontal and vertical dimensions of the display element P1 located on the side closest to the reduction are shown in Table 13 below.

[0230] Table 13

[0231] Longitudinal length 5.82mm Distance from the optical axis to the bottom edge of the display panel 1.313mm

[0232] Figure 12 This is a diagram illustrating an example of an image projected onto a flat screen during close-range projection (equivalent to approximately 100 inches) using the projection optics system LM1 based on Embodiment 2. Figure 13 This is a diagram illustrating an example of an image projected onto a flat screen during reference projection (equivalent to approximately 125 inches) using the projection optical system LM1 based on Embodiment 2. Figure 14 This is a diagram illustrating an example of an image projected onto a flat screen during long-distance projection (equivalent to approximately 150 inches) using the projection optics system LM1 based on Embodiment 2.

[0233] Figure 12 , Figure 13 and Figure 14 Simulation results of the grid distortion grid on the near-field side (approximately 100 inches), the reference side (approximately 125 inches), and the far-field side (approximately 150 inches) are shown respectively. Figure 12 , Figure 13 and Figure 14 As shown, good corrections were performed in the projection optical system LM1 of Example 2.

[0234] Furthermore, in the projection optical system LM1 of Embodiment 2, the X and Y coordinates of the display element P1 are specified as shown in Table 14 below. It should be noted that, since it is symmetrical about the X-axis, the coordinates are specified only on one side.

[0235] Table 14

[0236] F1 -5.184 7.145 F2 -2.592 7.145 F3 0 7.145 F4 -5.184 5.687 F5 -2.592 5.687 F6 0 5.687 F7 -5.184 4.229 F8 -2.592 4.229 F9 0 4.229 F10 -5.184 2.771 F11 -2.592 2.771 F12 0 2.771 F13 -5.184 1.313 F14 -2.592 1.313 F15 0 1.313

[0237] Figure 15 This is a dot plot showing a near-field projection (equivalent to about 100 inches) of the projection optical system LM1 based on Embodiment 2. Figure 16 This is a dot plot showing the reference projection (equivalent to approximately 125 inches) of the projection optical system LM1 based on Embodiment 2. Figure 17 This is a dot plot showing the projection distance (approximately 150 inches) of the projection optical system LM1 based on Embodiment 2. These dot plots were simulated under the conditions shown in Table 14 above. Figure 15 , Figure 16 and Figure 17 As shown, good corrections were performed in the projection optical system LM1 of Example 2.

[0238] In addition, the parameters of the projection optical system LM1 in Embodiment 2 are shown in Table 15 below.

[0239] Table 15

[0240]

[0241] In the projection optical system LM1 of Embodiment 2, the values ​​of conditions (1)-(8) above are shown in Table 16 below. That is, in the projection optical system LM1 of Embodiment 2, conditions (1)-(8) above are satisfied respectively.

[0242] Table 16

[0243]

[0244] Alternatively, from another perspective, the parameters of the projection optical system LM1 in Embodiment 2 are shown in Table 17 below.

[0245] Table 17

[0246]

[0247] In the projection optical system LM1 of Embodiment 2, the values ​​of the above conditions (9)-(12) are shown in Table 18 below. That is, in the projection optical system LM1 of Embodiment 2, the above conditions (9)-(12) are satisfied respectively.

[0248] Table 18

[0249]

[0250] As described above, the projection optical system LM1 in Embodiment 2 is as follows: Figure 12-17 The sample has good optical properties and satisfies conditions (1)-(12).

[0251] <Example 3>

[0252] The structure of the projection optical system in Example 3 is as follows: Figure 19 As shown. Moreover, Figure 18 This is a diagram showing the relationship between the projection optical system LM1 and the screen S1 in Embodiment 3, and an enlarged view of the projection optical system LM1 in Embodiment 3. Figure 18 For example, the relationship between the optical path of the projection optical system LM1 and the screen S1 in Embodiment 3 is shown. Figure 18 As shown, in the projection optical system LM1, the light is reflected back by the reflector M1, thereby achieving short focal length.

[0253] like Figure 19As shown, the projection optical system LM1 includes a first lens group G1, a second lens group G2, a third lens group G3, and a fourth lens group G4.

[0254] The first lens group G1 includes lenses L1-L10. In the first lens group G1, lenses L1-L10 are arranged sequentially from the narrowing side. The second lens group G2 includes lenses L11-L13. In the second lens group G2, lenses L11-L13 are arranged sequentially from the narrowing side.

[0255] The third lens group G3 includes lenses L14-L16. In the third lens group G3, lenses L14-L16 are arranged sequentially from the reduced side. The fourth lens group G4 is composed of lens L17. The reflecting part M1 is composed of a concave mirror. The reflecting part M1 is located below the optical axis AX1.

[0256] In the projection optical system LM1, an image is displayed on the left-hand side of the cover glass CG1 mounted on the display element P1. Prism PR1 and optical component CG2 are respectively positioned between the display element P1 and lens L1.

[0257] When focusing from the near side to the far side, the second lens group G2 and the third lens group G3 move from the reduced side to the magnified side, respectively.

[0258] The first lens group G1 is the positive group, as described above, and includes lenses L1-L10. Lens L1 is a positive convex-concave lens that convex towards the reduction side. Lens L2 is a biconvex positive lens. Lens L3 is a biconvex positive lens. Lens L4 is a negative convex-concave lens that is concave towards the reduction side. Lens L5 is a biconvex positive lens. Lens L6 is a biconcave negative lens. Lens L7 is a positive convex-concave lens that convex towards the reduction side. Lens L8 is a biconvex positive lens. Lens L9 is a positive convex-concave lens that convex towards the magnification side. Lens L10 is a biconcave negative lens.

[0259] Two lenses are formed by lenses L3 and L4. Three lenses are formed by lenses L5-L7. Two lenses are formed by lenses L9 and L10. Furthermore, both surfaces of lens L2 are aspherical.

[0260] Aperture D1 is positioned within the first lens group G1, between lenses L7 and L8. That is, aperture D1 is located within the first lens group G1. Aperture D1 and the first lens group G1 are fixed together.

[0261] Furthermore, the first lens group G1 includes lens groups G1-1 and G1-2. Lens group G1-1 is composed of lenses located in the region from the narrowest side to the aperture D1 among the multiple lenses included in the first lens group G1. Specifically, lens group G1-1 includes lenses L1-L7. Lens group G1-2 is composed of lenses located in the region from the aperture D1 to the magnifying side among the multiple lenses included in the first lens group G1. Specifically, lens group G1-2 includes lenses L8-L10.

[0262] The second lens group G2 is a positive group, as described above, and includes lenses L11-L13. Lens L11 is a biconvex positive lens. Lens L12 is a biconcave negative lens. Lens L13 is a biconvex positive lens. Furthermore, both surfaces of lens L11 are aspherical.

[0263] The third lens group G3 is the negative group, as described above, and includes lenses L14-L16. Lens L14 is a positive convex-concave lens that bulges towards the narrowing side. Lens L15 is a biconcave negative lens. Lens L16 is a biconcave negative convex-concave lens with a small thickness ratio, and its peripheral portion bends towards the narrowing side. Furthermore, both surfaces of lens L16 are aspherical.

[0264] The fourth lens group, G4, is a negative group, as described above, and includes lens L17. Lens L17 is a biconcave negative lens.

[0265] In Example 3, the focal length (F), number of apertures (NA), and maximum incident angle (θM) of the entire projection optical system LM1 are as follows.

[0266] F = 1.9mm

[0267] NA = 0.23

[0268] θM=78°

[0269] The data (RDN) of the projection optical system LM1 in Example 3 are shown in Table 19 below.

[0270] Table 19

[0271]

[0272] In Table 19, the lens surfaces with an asterisk (*) in the number column are aspherical. That is, the 10th, 11th, 25th, 26th, 35th, 36th, and 39th surfaces marked with an asterisk are aspherical. The parameters of each aspherical surface in the above formula (A1) are shown in Table 20 below.

[0273] Table 20

[0274] K -1.782 -94.028 -4.503 17.666 -20.637 -32.801 -3.762 C4 -1.63863E-05 1.15457E-05 -1.24280E-05 -2.34499E-06 -3.33590E-06 -4.20083E-05 -4.60988E-06 C6 -2.80601E-08 -7.90482E-09 2.44122E-08 -3.46444E-08 3.29998E-08 3.68600E-08 2.90629E-09 C8 1.52881E-11 -7.54032E-11 1.98789E-10 3.35513E-10 -6.50160E-11 1.97977E-12 -1.67568E-12 C10 4.46415E-13 1.30739E-12 -8.82034E-13 -9.75581E-13 0.00000E+00 -6.12551E-14 6.59545E-16 C12 3.89666E-15 1.83688E-15 -1.03079E-16 4.93151E-15 0.00000E+00 3.07946E-17 -1.67128E-19 C14 8.71043E-18 1.56081E-18 -4.10083E-18 -4.64533E-18 0.00000E+00 -4.18571E-20 2.40332E-23 C16 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 2.28092E-23 -1.51673E-27

[0275] Regarding D (interval) in Table 19, for surfaces marked with "S", displacement is achieved through focusing. During focusing, "S24" between the first lens group G1 and the second lens group G2, "S30" between the second lens group G2 and the third lens group G3, and "S36" between the third lens group G3 and the fourth lens group G4 are displaced respectively. Furthermore, the displacement between the reflector M1 and the screen surface is "S39". Since light is reflected, S39 is set to negative (-). Table 21 below shows how S24, S30, S36, and S39 are displaced. It should be noted that the distances to the screen are selected as close (approximately 80 inches), reference (approximately 125 inches), and far (approximately 150 inches) as references.

[0276] Table 21

[0277] close up 5.64 7.75 3.65 -346.8 benchmark 5.94 8.51 2.59 -534.2 long distance 6.02 8.7 2.32 -638.1

[0278] Furthermore, in the projection optical system LM1 of Embodiment 3, the horizontal and vertical dimensions of the display element P1 located on the side closest to the reduction are shown in Table 22 below.

[0279] Table 22

[0280] Longitudinal length 5.82mm Distance from the optical axis to the bottom edge of the display panel 1.313mm

[0281] Figure 20 This is a diagram illustrating an example of an image projected onto a flat screen during close-range projection (equivalent to approximately 80 inches) using the projection optics system LM1 based on Embodiment 3. Figure 21 This is a diagram illustrating an example of an image projected onto a flat screen during reference projection (equivalent to approximately 125 inches) using the projection optical system LM1 based on Embodiment 3. Figure 22 This is a diagram illustrating an example of an image projected onto a flat screen during long-distance projection (equivalent to approximately 150 inches) using the projection optical system LM1 based on Embodiment 3. Figure 20 , Figure 21 and Figure 22 Simulation results of the grid distortion grid on the near-field side (approximately 80 inches), the baseline side (approximately 125 inches), and the far-field side (approximately 150 inches) are shown respectively. Figure 20 , Figure 21 and Figure 22 As shown, good corrections were performed in the projection optical system LM1 of Example 3.

[0282] Furthermore, in the projection optical system LM1 of Embodiment 3, the X and Y coordinates of the display element P1 are specified as shown in Table 23 below. It should be noted that, since it is symmetrical about the X-axis, the coordinates are specified only on one side.

[0283] Table 23

[0284] F1 -5.184 7.145 F2 -2.592 7.145 F3 0 7.145 F4 -5.184 5.687 F5 -2.592 5.687 F6 0 5.687 F7 -5.184 4.229 F8 -2.592 4.229 F9 0 4.229 F10 -5.184 2.771 F11 -2.592 2.771 F12 0 2.771 F13 -5.184 1.313 F14 -2.592 1.313 F15 0 1.313

[0285] Figure 23 This is a dot plot showing a near-distance projection (equivalent to about 80 inches) of the projection optical system LM1 based on Embodiment 3. Figure 24 This is a dot plot showing the reference projection (equivalent to approximately 125 inches) of the projection optical system LM1 based on Embodiment 3. Figure 25 This is a dot plot showing the projection distance (approximately 150 inches) of the projection optical system LM1 based on Embodiment 3. These dot plots were simulated under the conditions shown in Table 23 above. Figure 23 , Figure 24 and Figure 25 As shown, good corrections were performed in the projection optical system LM1 of Example 3.

[0286] In addition, the parameters of the projection optical system LM1 in Embodiment 3 are shown in Table 24 below.

[0287] Table 24

[0288]

[0289] In the projection optical system LM1 of Embodiment 3, the values ​​of conditions (1)-(8) above are shown in Table 25 below. That is, in the projection optical system LM1 of Embodiment 3, conditions (1)-(8) above are satisfied respectively.

[0290] Table 25

[0291]

[0292] Alternatively, from another perspective, the parameters of the projection optical system LM1 in Embodiment 3 are shown in Table 26 below.

[0293] Table 26

[0294]

[0295] In the projection optical system LM1 of Embodiment 3, the values ​​of the above conditions (9)-(12) are shown in Table 27 below. That is, in the projection optical system LM1 of Embodiment 3, the above conditions (9)-(12) are satisfied respectively.

[0296] Table 27

[0297]

[0298] As described above, the projection optical system LM1 in Embodiment 3 is as follows: Figure 20-25 The sample has good optical properties and satisfies conditions (1)-(12).

[0299] <Example 4>

[0300] The structure of the projection optical system in Example 4 is as follows: Figure 27 As shown. Moreover, Figure 26 This is a diagram showing the relationship between the projection optical system LM1 and the screen S1 in Embodiment 4, and an enlarged view of the projection optical system LM1 in Embodiment 4. Figure 26 For example, the relationship between the optical path of the projection optical system LM1 and the screen S1 in Embodiment 4 is shown. Figure 26 As shown, in the projection optical system LM1, the light is reflected back by the reflector M1, thereby achieving short focal length.

[0301] like Figure 27 As shown, the projection optical system LM1 includes a first lens group G1, a second lens group G2, and a third lens group G3.

[0302] The first lens group G1 includes lenses L1-L12. In the first lens group G1, lenses L1-L12 are arranged sequentially from the narrowing side. The second lens group G2 includes lenses L13-L15. In the second lens group G2, lenses L13-L15 are arranged sequentially from the narrowing side.

[0303] The third lens group G3 comprises lenses L16-L22. In the third lens group G3, lenses L16-L22 are arranged sequentially from the reduced-size side. The reflecting part M1 is composed of a concave mirror. The reflecting part M1 is located below the optical axis AX1.

[0304] In the projection optical system LM1, an image is displayed on the left-hand side of the cover glass CG1 mounted on the display element P1. Prism PR1 and optical component CG2 are respectively positioned between the display element P1 and lens L1.

[0305] When focusing from the near side to the far side, the second lens group G2 and the third lens group G3 move from the magnifying side to the reducing side, respectively.

[0306] The first lens group G1 is the positive group, as described above, and includes lenses L1-L12. Lens L1 is a biconvex positive lens. Lens L2 is a biconvex positive lens. Lens L3 is a negative convex-concave lens that is concave towards the reduction side. Lens L4 is a positive convex-concave lens that convex towards the reduction side. Lens L5 is a biconvex positive lens. Lens L6 is a biconcave negative lens. Lens L7 is a positive convex-concave lens that convex towards the reduction side. Lens L8 is a positive convex-concave lens that convex towards the magnification side. Lens L9 is a biconvex positive lens. Lens L10 is a biconcave negative lens. Lens L11 is a positive convex-concave lens that convex towards the reduction side. Lens L12 is a biconvex positive lens.

[0307] Two lenses are formed by lenses L2 and L3. Three lenses are formed by lenses L5-L7. Two lenses are formed by lenses L10 and L11. Furthermore, the reduced-width surface of lens L4 is aspherical, and both surfaces of lens L12 are aspherical.

[0308] Aperture D1 is positioned within the first lens group G1, between lenses L8 and L9. That is, aperture D1 is located within the first lens group G1. Aperture D1 and the first lens group G1 are fixed together.

[0309] Furthermore, the first lens group G1 includes lens groups G1-1 and G1-2. Lens group G1-1 is composed of lenses located in the region from the narrowest side to the aperture D1 among the multiple lenses included in the first lens group G1. Specifically, lens group G1-1 includes lenses L1-L8. Lens group G1-2 is composed of lenses located in the region from the aperture D1 to the magnifying side among the multiple lenses included in the first lens group G1. Specifically, lens group G1-2 includes lenses L9-L12.

[0310] The second lens group G2 is the positive group, as described above, and includes lenses L13-L15. Lens L13 is a positive convex-concave lens that bulges towards the magnifying side. Lens L14 is a negative convex-concave lens that is concave towards the reducing side. Lens L15 is a negative convex-concave lens that is concave towards the reducing side.

[0311] The third lens group G3 is the negative group, as described above, and includes lenses L16-L22. Lens L16 is a biconvex positive lens. Lens L17 is a negative convex-concave lens that is concave towards the reduction side. Lens L18 is a biconcave negative lens. Lens L19 is a positive convex-concave lens that convex towards the reduction side. Lens L20 is a biconcave negative convex-concave lens with a small peripheral thickness ratio. Lens L21 is a negative convex-concave lens that is concave towards the magnification side. Lens L22 is a negative convex-concave lens that is concave towards the reduction side and has a small peripheral thickness ratio.

[0312] In Example 4, the focal length (F), number of apertures (NA), and maximum incident angle (θM) of the entire projection optical system LM1 are as follows.

[0313] F = 1.9mm

[0314] NA = 0.23

[0315] θM=78°

[0316] The data (RDN) of the projection optical system LM1 in Example 4 are shown in Table 28 below.

[0317] Table 28

[0318]

[0319] In Table 28, the lens surfaces with an asterisk (*) in the number column are aspherical. That is, the 13th, 27th, 28th, 42nd, 43rd, 46th, 47th, and 48th surfaces marked with an asterisk are all aspherical. The parameters of each aspherical surface in the above formula (A1) are shown in Table 29 below.

[0320] Table 29

[0321] K -6.15 -12.246 78.608 -10.05 -77.526 0 0 -3.339 C4 -4.98270E-05 -1.55150E-05 -2.42390E-05 1.08030E-06 -3.37350E-05 4.15430E-06 1.28570E-06 -4.69800E-06 C6 -1.61900E-07 -1.35060E-07 -5.26240E-08 7.30390E-08 2.49600E-08 -4.98150E-09 -1.44850E-09 2.85850E-09 C8 4.79970E-10 3.57110E-10 4.66520E-10 -1.57860E-10 6.51630E-12 -1.41100E-11 -8.76030E-12 -1.67540E-12 C10 3.82880E-12 -1.47720E-11 -1.25180E-11 1.12960E-13 -1.62560E-14 -4.12140E-14 -8.18450E-15 6.68420E-16 C12 0.00000E+00 1.36810E-25 1.21020E-25 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 -1.71270E-19 C14 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 2.39880E-23 C16 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 -1.39670E-27

[0322] Regarding D (interval) in Table 28, for surfaces marked with "S", displacement is achieved through focusing. During focusing, the displacements are as follows: "S28" between the first lens group G1 and the second lens group G2, "S33" between the second lens group G2 and the third lens group G3, and "S47" between the third lens group G3 and the reflector M1. Furthermore, the displacement between the reflector M1 and the screen surface is "S48". Since light is reflected, S48 is set to negative (-). Table 30 below shows how S28, S33, S47, and S48 are displaced. It should be noted that the distances to the screen are selected as close (approximately 100 inches), reference (approximately 125 inches), and far (approximately 150 inches) as references.

[0323] Table 30

[0324] close up 6.126 1.756 67.642 -430 benchmark 4.772 3.278 67.475 -533.69 long distance 3.873 4.286 67.366 -637.36

[0325] Furthermore, in the projection optical system LM1 of Embodiment 4, the horizontal and vertical dimensions of the display element P1 located on the side closest to the reduction are shown in Table 31 below.

[0326] Table 31

[0327] Longitudinal length 5.82mm Distance from the optical axis to the bottom edge of the display panel 1.313mm

[0328] Figure 28This is a diagram illustrating an example of an image projected onto a flat screen during close-range projection (equivalent to approximately 100 inches) using the projection optics system LM1 based on Embodiment 4. Figure 29 This is a diagram illustrating an example of an image projected onto a flat screen during reference projection (equivalent to approximately 125 inches) using the projection optics system LM1 based on Embodiment 4. Figure 30 This is a diagram illustrating an example of an image projected onto a flat screen during long-distance projection (equivalent to approximately 150 inches) using the projection optics system LM1 based on Embodiment 4. Figure 28 , Figure 29 and Figure 30 Simulation results of the grid distortion grid on the near-field side (approximately 100 inches), the reference side (approximately 125 inches), and the far-field side (approximately 150 inches) are shown respectively. Figure 28 , Figure 29 and Figure 30 As shown, good corrections were performed in the projection optical system LM1 of Example 4.

[0329] Furthermore, in the projection optical system LM1 of Embodiment 4, the X and Y coordinates of the display element P1 are specified as shown in Table 32 below. It should be noted that, since it is symmetrical about the X-axis, the coordinates are specified only on one side.

[0330] Table 32

[0331] F1 -5.184 7.145 F2 -2.592 7.145 F3 0 7.145 F4 -5.184 5.687 F5 -2.592 5.687 F6 0 5.687 F7 -5.184 4.229 F8 -2.592 4.229 F9 0 4.229 F10 -5.184 2.771 F11 -2.592 2.771 F12 0 2.771 F13 -5.184 1.313 F14 -2.592 1.313 F15 0 1.313

[0332] Figure 31 This is a dot plot showing a close-range projection (equivalent to about 100 inches) of the projection optical system LM1 based on Embodiment 4. Figure 32 This is a dot plot showing the reference projection (equivalent to approximately 125 inches) of the projection optical system LM1 based on Embodiment 4. Figure 33 This is a dot plot showing the projection distance (approximately 150 inches) of the projection optical system LM1 based on Embodiment 4. These dot plots were simulated under the conditions shown in Table 32 above. Figure 31 , Figure 32 and Figure 33 As shown, good corrections were performed in the projection optical system LM1 of Example 4.

[0333] In addition, the parameters of the projection optical system LM1 in Embodiment 4 are shown in Table 33 below.

[0334] Table 33

[0335]

[0336] In the projection optical system LM1 of Embodiment 4, the values ​​of conditions (1)-(8) above are shown in Table 34 below. That is, in the projection optical system LM1 of Embodiment 4, conditions (1)-(8) above are satisfied respectively.

[0337] Table 34

[0338]

[0339] As described above, the projection optical system LM1 in Embodiment 4 is as follows: Figure 28-33 The sample has good optical properties and satisfies conditions (1)-(8).

[0340] <Example 5>

[0341] The structure of the projection optical system in Example 5 is as follows: Figure 35 As shown. Moreover, Figure 34 This is a diagram showing the relationship between the projection optical system LM1 and the screen S1 in Embodiment 5, and an enlarged view of the projection optical system LM1 in Embodiment 5. Figure 34 For example, the relationship between the optical path of the projection optical system LM1 and the screen S1 in Embodiment 5 is shown. Figure 34 As shown, in the projection optical system LM1, the light is reflected back by the reflector M1, thereby achieving short focal length.

[0342] like Figure 35 As shown, the projection optical system LM1 includes a first lens group G1, a second lens group G2, and a third lens group G3.

[0343] The first lens group G1 includes lenses L1-L11. In the first lens group G1, lenses L1-L11 are arranged sequentially from the narrowing side. The second lens group G2 includes lenses L12-L14. In the second lens group G2, lenses L12-L14 are arranged sequentially from the narrowing side.

[0344] The third lens group G3 includes lenses L15-L18. In the third lens group G3, lenses L15-L18 are arranged sequentially from the reduced-size side. The reflecting part M1 is composed of a concave mirror. The reflecting part M1 is located below the optical axis AX1.

[0345] In the projection optical system LM1, an image is displayed on the left-hand side of the cover glass CG1 mounted on the display element P1. Prism PR1 and optical component CG2 are respectively positioned between the display element P1 and lens L1.

[0346] When focusing from the near side to the far side, the second lens group G2 and the third lens group G3 move from the magnifying side to the reducing side, respectively.

[0347] The first lens group G1 is the positive group, as described above, and includes lenses L1-L11. Lens L1 is a positive convex-concave lens convex towards the reduction side. Lens L2 is a positive convex-concave lens convex towards the reduction side. Lens L3 is a biconvex positive lens. Lens L4 is a positive convex-concave lens convex towards the magnification side. Lens L5 is a biconcave negative lens. Lens L6 is a biconvex positive lens. Lens L7 is a positive convex-concave lens convex towards the magnification side. Lens L8 is a biconvex positive lens. Lens L9 is a biconcave negative lens. Lens L10 is a positive convex-concave lens convex towards the reduction side. Lens L11 is a biconvex positive lens.

[0348] A three-element joint lens is formed by lenses L4-L6. A two-element joint lens is formed by lenses L9 and L10. Furthermore, two surfaces of each of lenses L3 and L11 are aspherical.

[0349] Aperture D1 is positioned within the first lens group G1, between lenses L7 and L8. That is, aperture D1 is located within the first lens group G1. Aperture D1 and the first lens group G1 are fixed together.

[0350] Furthermore, the first lens group G1 includes lens groups G1-1 and G1-2. Lens group G1-1 is composed of lenses located in the region from the narrowest side to the aperture D1 among the multiple lenses included in the first lens group G1. Specifically, lens group G1-1 includes lenses L1-L7. Lens group G1-2 is composed of lenses located in the region from the aperture D1 to the magnifying side among the multiple lenses included in the first lens group G1. Specifically, lens group G1-2 includes lenses L8-L11.

[0351] The second lens group G2 is the positive group, as described above, and includes lenses L12-L14. Lens L12 is a positive convex-concave lens that bulges towards the magnifying side. Lens L13 is a negative convex-concave lens that is concave towards the reducing side. Lens L14 is a positive convex-concave lens that bulges towards the magnifying side.

[0352] The third lens group G3 is a negative group, as described above, and includes lenses L15-L18. Lens L15 is a positive convex-concave lens that bulges towards the reduction side. Lens L16 is a negative convex-concave lens that is concave towards the magnification side. Lens L17 is a biconcave negative lens with a bent peripheral portion. Lens L18 is a negative convex-concave lens that is concave towards the magnification side. Furthermore, both surfaces of lens L17 are aspherical.

[0353] In Example 5, the focal length (F), number of apertures (NA), and maximum incident angle (θM) of the entire projection optical system LM1 are as follows.

[0354] F = 2.1 mm

[0355] NA = 0.23

[0356] θM=77°

[0357] The data (RDN) of the projection optical system LM1 in Example 5 are shown in Table 35 below.

[0358] Table 35

[0359]

[0360] In Table 35, the lens surfaces with an asterisk (*) in the number column are aspherical. That is, the 12th, 13th, 26th, 27th, 37th, 38th, and 41st surfaces marked with an asterisk are aspherical. The parameters of each aspherical surface in the above formula (A1) are shown in Table 36 below.

[0361] Table 36

[0362] K -0.971 0 -21.428 101.153 -8.618 -22.09 -3.424 C4 -1.89029E-05 4.46338E-05 -1.34519E-05 -1.45302E-05 -1.39055E-05 -2.92771E-05 -4.76219E-06 C6 -1.93168E-07 -4.93836E-07 -1.76411E-08 1.29601E-08 2.52059E-07 1.08669E-07 2.91000E-09 C8 -5.54449E-10 -1.19586E-09 -3.86402E-10 -1.63061E-10 -1.10863E-09 -2.85170E-10 -1.67973E-12 C10 -1.11877E-11 4.88864E-12 -2.31678E-12 -3.04070E-12 2.84848E-12 4.05804E-13 6.66731E-16 C12 0 0 0 0 -4.48925E-15 4.21284E-17 -1.71162E-19 C14 0 0 0 0 3.87794E-18 -8.76630E-19 2.41442E-23 C16 0 0 0 0 -1.36507E-21 7.43802E-22 -1.39714E-27

[0363] Regarding D (interval) in Table 35, for surfaces marked with "S", displacement is achieved through focusing. During focusing, the displacements are as follows: "S27" between the first lens group G1 and the second lens group G2, "S32" between the second lens group G2 and the third lens group G3, and "S40" between the third lens group G3 and the reflector M1. Furthermore, the displacement between the reflector M1 and the screen surface is "S41". Since light is reflected, S41 is set to negative (-). Table 37 below shows how S27, S32, S40, and S41 are displaced. It should be noted that the distances to the screen are selected as close (approximately 100 inches), reference (approximately 125 inches), and far (approximately 150 inches) as references.

[0364] Table 37

[0365] close up 6.41 1.1 83.314 -470 benchmark 4.94 2.77 83.115 -583.59 long distance 3.94 3.87 83.01 -701.69

[0366] Furthermore, in the projection optical system LM1 of Embodiment 5, the horizontal and vertical dimensions of the display element P1 located on the side closest to the reduction are shown in Table 38 below.

[0367] Table 38

[0368] Longitudinal length 5.82mm Distance from the optical axis to the bottom edge of the display panel 1.313mm

[0369] Figure 36 This is a diagram illustrating an example of an image projected onto a flat screen during close-range projection (equivalent to approximately 100 inches) using the projection optics system LM1 based on Embodiment 5. Figure 37 This is a diagram illustrating an example of an image projected onto a flat screen during reference projection (equivalent to approximately 125 inches) using the projection optical system LM1 based on Embodiment 5. Figure 38 This is a diagram illustrating an example of an image projected onto a flat screen during long-distance projection (equivalent to approximately 150 inches) using the projection optics system LM1 based on Embodiment 5. Figure 36 , Figure 37 and Figure 38 Simulation results of the grid distortion grid on the near-field side (approximately 100 inches), the reference side (approximately 125 inches), and the far-field side (approximately 150 inches) are shown respectively. Figure 36 , Figure 37 and Figure 38 As shown, good corrections were performed in the projection optical system LM1 of Example 5.

[0370] Furthermore, in the projection optical system LM1 of Embodiment 5, the X and Y coordinates of the display element P1 are specified as shown in Table 39 below. It should be noted that, since it is symmetrical about the X-axis, the coordinates are specified only on one side.

[0371] Table 39

[0372] F1 -5.184 7.145 F2 -2.592 7.145 F3 0 7.145 F4 -5.184 5.687 F5 -2.592 5.687 F6 0 5.687 F7 -5.184 4.229 F8 -2.592 4.229 F9 0 4.229 F10 -5.184 2.771 F11 -2.592 2.771 F12 0 2.77l F13 -5.184 1.313 F14 -2.592 1.313 F15 0 1.313

[0373] Figure 39 This is a dot plot showing a near-field projection (equivalent to about 100 inches) of the projection optical system LM1 based on Embodiment 5. Figure 40 This is a dot plot showing the reference projection (equivalent to approximately 125 inches) of the projection optical system LM1 based on Embodiment 5. Figure 41 This is a dot plot showing the projection distance (approximately 150 inches) of the projection optical system LM1 based on Embodiment 5. These dot plots were simulated under the conditions shown in Table 39 above. Figure 39 , Figure 40 and Figure 41 As shown, good corrections were performed in the projection optical system LM1 of Example 5.

[0374] In addition, the parameters of the projection optical system LM1 in Embodiment 5 are shown in Table 40 below.

[0375] Table 40

[0376]

[0377] In the projection optical system LM1 of Embodiment 5, the values ​​of conditions (1)-(8) above are shown in Table 41 below. That is, in the projection optical system LM1 of Embodiment 5, conditions (1)-(8) above are satisfied respectively.

[0378] Table 41

[0379]

[0380] As described above, the projection optical system LM1 in Embodiment 5 is as follows: Figure 36-41 The sample has good optical properties and satisfies conditions (1)-(8).

[0381] <Example 6>

[0382] The structure of the projection optical system in Example 6 is as follows: Figure 43 As shown. Moreover, Figure 42 This is a diagram showing the relationship between the projection optical system LM1 and the screen S1 in Embodiment 6, and an enlarged view of the projection optical system LM1 in Embodiment 6. Figure 42 For example, the relationship between the optical path of the projection optical system LM1 and the screen S1 in Embodiment 6 is shown. Figure 42 As shown, in the projection optical system LM1, the light is reflected back by the reflector M1, thereby achieving ultra-short focal length focusing.

[0383] like Figure 43 As shown, the projection optical system LM1 includes a first lens group G1, a second lens group G2, and a third lens group G3.

[0384] The first lens group G1 includes lenses L1-L12. In the first lens group G1, lenses L1-L12 are arranged sequentially from the narrowing side. The second lens group G2 includes lenses L13-L15. In the second lens group G2, lenses L13-L15 are arranged sequentially from the narrowing side.

[0385] The third lens group G3 includes lenses L16-L19. In the third lens group G3, lenses L16-L19 are arranged sequentially from the reduced-size side. The reflecting part M1 is composed of a concave mirror. The reflecting part M1 is located below the optical axis AX1.

[0386] In the projection optical system LM1, an image is displayed on the left-hand side of the cover glass CG1 mounted on the display element P1. Prism PR1 and optical component CG2 are respectively positioned between the display element P1 and lens L1.

[0387] When focusing from the near side to the far side, the second lens group G2 and the third lens group G3 move from the magnifying side to the reducing side, respectively.

[0388] The first lens group G1 is the positive group, as described above, and includes lenses L1-L12. Lens L1 is a biconvex positive lens. Lens L2 is a positive convex-concave lens that convex towards the reduction side. Lens L3 is a biconvex positive lens. Lens L4 is a biconvex positive lens. Lens L5 is a biconcave negative lens. Lens L6 is a positive convex-concave lens that convex towards the reduction side. Lens L7 is a positive convex-concave lens that convex towards the magnification side. Lens L8 is a negative convex-concave lens that is concave towards the magnification side. Lens L9 is a biconvex positive lens. Lens L10 is a biconcave negative lens. Lens L11 is a positive convex-concave lens that convex towards the reduction side. Lens L12 is a biconvex positive lens.

[0389] Three-element jointed lenses are formed by lenses L4-L6. Two-element jointed lenses are formed by lenses L8 and L9. Furthermore, two-element jointed lenses are formed by lenses L10 and L11. Moreover, two surfaces of each of lenses L3 and L12 are aspherical.

[0390] Aperture D1 is positioned within the first lens group G1, between lenses L7 and L8. That is, aperture D1 is located within the first lens group G1. Aperture D1 and the first lens group G1 are fixed together.

[0391] Furthermore, the first lens group G1 includes lens groups G1-1 and G1-2. Lens group G1-1 is composed of lenses located in the region from the narrowest side to the aperture D1 among the multiple lenses included in the first lens group G1. Specifically, lens group G1-1 includes lenses L1-L7. Lens group G1-2 is composed of lenses located in the region from the aperture D1 to the magnifying side among the multiple lenses included in the first lens group G1. Specifically, lens group G1-2 includes lenses L8-L12.

[0392] The second lens group G2 is a positive group, as described above, and includes lenses L13-L15. Lens L13 is a positive convex-concave lens that convexes towards the magnifying side. Lens L14 is a negative convex-concave lens that is concave towards the reducing side. Lens L15 is a biconvex positive lens.

[0393] The third lens group G3 is a negative group, as described above, and includes lenses L16-L19. Lens L16 is a positive convex-concave lens that convexes towards the reduction side. Lens L17 is a negative convex-concave lens that is concave towards the magnification side. Lens L18 is a biconcave negative convex-concave lens with a small thickness ratio, and its peripheral portion bends towards the reduction side. Lens L19 is a biconcave negative lens. Furthermore, both surfaces of lenses L18 and L19 are aspherical.

[0394] In Example 6, the focal length (F), number of apertures (NA), and maximum incident angle (θM) of the entire projection optical system LM1 are as follows.

[0395] F = 1.9mm

[0396] NA = 0.23

[0397] θM=78°

[0398] The data (RDN) of the projection optical system LM1 in Example 6 are shown in Table 42 below.

[0399] Table 42

[0400]

[0401] In Table 42, the lens surfaces with an asterisk (*) in the number column are aspherical. That is, the 12th, 13th, 27th, 28th, 39th, 40th, 41st, and 42nd surfaces marked with an asterisk are aspherical. The parameters of each aspherical surface in the above formula (A1) are shown in Table 43 below.

[0402] Table 43

[0403] K -1.57 0 -10.878 75.882 -15.135 -30.574 -3.018 0.426 -3.187 C4 -3.22781E-05 3.00152E-05 -1.66328E-05 -1.55155E-05 -5.38718E-06 -2.80490E-05 7.14529E-07 -4.36334E-08 -4.63888E-06 C6 -2.19802E-07 -4.97148E-07 -2.21066E-09 -2.40860E-08 6.30822E-08 3.13605E-08 -6.76569E-10 1.00871E-09 2.82128E-09 C8 -1.93907E-09 5.51257E-10 1.45059E-10 3.43826E-10 -1.17014E-10 2.61665E-12 -1.34769E-12 -6.18108E-14 -1.66372E-12 C10 2.55737E-12 -1.49619E-12 -3.40891E-12 -2.95634E-12 0.00000E+00 -6.52603E-14 -8.14355E-16 -3.27607E-15 6.61161E-16 C12 0 0 0 0 0 1.81807E-18 0 0 -1.68092E-19 C14 0 0 0 0 0 0 0 0 2.35386E-23 C16 0 0 0 0 0 0 0 0 -1.44590E-27

[0404] Regarding D (interval) in Table 42, for surfaces marked with "S", displacement is achieved through focusing. During focusing, the displacements are as follows: "S28" between the first lens group G1 and the second lens group G2, "S33" between the second lens group G2 and the third lens group G3, and "S41" between the third lens group G3 and the reflector M1. Furthermore, the displacement between the reflector M1 and the screen surface is "S42". Since light is reflected, S42 is set to negative (-). Table 44 below shows how S28, S33, S41, and S42 are displaced. It should be noted that the distances to the screen are selected as close (approximately 100 inches), reference (approximately 125 inches), and far (approximately 150 inches) as references.

[0405] Table 44

[0406] close up 7.666 1.1 77.231 -430 benchmark 5.053 3.908 77.036 -533.642 long distance 3.102 5.975 76.92 -641.482

[0407] Furthermore, in the projection optical system LM1 of Embodiment 6, the horizontal and vertical dimensions of the display element P1 located at the position closest to the reduction side are shown in Table 45 below.

[0408] Table 45

[0409] Longitudinal length 5.82mm Distance from the optical axis to the bottom edge of the display panel 1.313mm

[0410] Figure 44 This is a diagram illustrating an example of an image projected onto a flat screen during close-range projection (equivalent to approximately 100 inches) using the projection optics system LM1 based on Embodiment 6. Figure 45This is a diagram illustrating an example of an image projected onto a flat screen during reference projection (equivalent to approximately 125 inches) using the projection optics system LM1 based on Embodiment 6. Figure 46 This is a diagram illustrating an example of an image projected onto a flat screen during long-distance projection (equivalent to approximately 150 inches) using the projection optics system LM1 based on Embodiment 6. Figure 44 , Figure 45 and Figure 46 Simulation results of the grid distortion grid on the near-field side (approximately 100 inches), the reference side (approximately 125 inches), and the far-field side (approximately 150 inches) are shown respectively. Figure 44 , Figure 45 and Figure 46 As shown, good corrections were performed in the projection optical system LM1 of Example 6.

[0411] Furthermore, in the projection optical system LM1 of Embodiment 6, the X and Y coordinates of the display element P1 are specified as shown in Table 46 below. It should be noted that, since it is symmetrical about the X-axis, the coordinates are specified only on one side.

[0412] Table 46

[0413] F1 -5.184 7.145 F2 -2.592 7.145 F3 0 7.145 F4 -5.184 5.687 F5 -2.592 5.687 F6 0 5.687 F7 -5.184 4.229 F8 -2.592 4.229 F9 0 4.229 F10 -5.184 2.771 F11 -2.592 2.771 F12 0 2.771 F13 -5.184 1.313 F14 -2.592 1.313 F15 0 1.313

[0414] Figure 47 This is a dot plot showing a close-range projection (equivalent to about 100 inches) of the projection optical system LM1 based on Embodiment 6. Figure 48 This is a dot plot showing the reference projection (equivalent to approximately 125 inches) of the projection optical system LM1 based on Embodiment 6. Figure 49 This is a dot plot showing the projection distance (approximately 150 inches) of the projection optical system LM1 based on Embodiment 6. These dot plots were simulated under the conditions shown in Table 46 above. Figure 47 , Figure 48 and Figure 49 As shown, good corrections were performed in the projection optical system LM1 of Example 6.

[0415] In addition, the parameters of the projection optical system LM1 in Embodiment 6 are shown in Table 47 below.

[0416] Table 47

[0417]

[0418] In the projection optical system LM1 of Embodiment 6, the values ​​of conditions (1)-(8) above are shown in Table 48 below. That is, in the projection optical system LM1 of Embodiment 6, conditions (1)-(8) above are satisfied respectively.

[0419] Table 48

[0420]

[0421] As described above, the projection optical system LM1 in Embodiment 6 is as follows: Figures 44-49 The sample has good optical properties and satisfies conditions (1)-(8).

[0422] <Example 7>

[0423] The structure of the projection optical system in Example 7 is as follows: Figure 51 As shown. Moreover, Figure 50 This is a diagram showing the relationship between the projection optical system LM1 and the screen S1 in Embodiment 7, and an enlarged view of the projection optical system LM1 in Embodiment 7. Figure 50 For example, the relationship between the optical path of the projection optical system LM1 and the screen S1 in Embodiment 7 is shown. Figure 50 As shown, in the projection optical system LM1, the light is reflected back by the reflector M1, thereby achieving short focal length.

[0424] like Figure 51 As shown, the projection optical system LM1 includes a first lens group G1, a second lens group G2, and a third lens group G3.

[0425] The first lens group G1 includes lenses L1-L11. In the first lens group G1, lenses L1-L11 are arranged sequentially from the narrowing side. The second lens group G2 includes lenses L12-L14. In the second lens group G2, lenses L12-L14 are arranged sequentially from the narrowing side.

[0426] The third lens group G3 includes lenses L15-L18. In the third lens group G3, lenses L15-L18 are arranged sequentially from the reduced-size side. The reflecting part M1 is composed of a concave mirror. The reflecting part M1 is located below the optical axis AX1.

[0427] In the projection optical system LM1, an image is displayed on the left-hand side of the cover glass CG1 mounted on the display element P1. Prism PR1 and optical component CG2 are respectively positioned between the display element P1 and lens L1.

[0428] When focusing from the near side to the far side, the second lens group G2 and the third lens group G3 move from the magnifying side to the reducing side, respectively.

[0429] The first lens group G1 is the positive group, as described above, and includes lenses L1-L11. Lens L1 is a positive convex-concave lens convex towards the reduction side. Lens L2 is a positive convex-concave lens convex towards the reduction side. Lens L3 is a biconvex positive lens. Lens L4 is a biconvex positive lens. Lens L5 is a biconcave negative lens. Lens L6 is a biconvex positive lens. Lens L7 is a positive convex-concave lens convex towards the magnification side. Lens L8 is a biconvex positive lens. Lens L9 is a biconcave negative lens. Lens L10 is a positive convex-concave lens convex towards the reduction side. Lens L11 is a biconvex positive lens.

[0430] Three-element jointed lenses are formed by lenses L4-L6. Two-element jointed lenses are formed by lenses L9 and L10. Furthermore, two-element jointed lenses are formed by lenses L12 and L13. Moreover, two surfaces of each of lenses L3 and L11 are aspherical.

[0431] Aperture D1 is positioned within the first lens group G1, between lenses L7 and L8. That is, aperture D1 is located within the first lens group G1. Aperture D1 and the first lens group G1 are fixed together.

[0432] Furthermore, the first lens group G1 includes lens groups G1-1 and G1-2. Lens group G1-1 is composed of lenses located in the region from the narrowest side to the aperture D1 among the multiple lenses included in the first lens group G1. Specifically, lens group G1-1 includes lenses L1-L7. Lens group G1-2 is composed of lenses located in the region from the aperture D1 to the magnifying side among the multiple lenses included in the first lens group G1. Specifically, lens group G1-2 includes lenses L8-L11.

[0433] The second lens group G2 is a positive group, as described above, and includes lenses L12-L14. Lens L12 is a negative convex-concave lens that convexes towards the magnifying side. Lens L13 is a negative convex-concave lens that is concave towards the reducing side. Lens L14 is a biconvex positive lens.

[0434] The third lens group G3 is a negative group, as described above, and includes lenses L15-L18. Lens L15 is a positive convex-concave lens that convexes towards the reduction side. Lens L16 is a negative convex-concave lens that is concave towards the magnification side. Lens L17 is a biconcave negative convex-concave lens with a small thickness ratio, and its peripheral portion bends towards the reduction side. Lens L18 is a biconcave negative lens. Furthermore, both surfaces of lens L17 are aspherical.

[0435] In Example 7, the focal length (F), number of apertures (NA), and maximum incident angle (θM) of the entire projection optical system LM1 are as follows.

[0436] F = 1.9mm

[0437] NA = 0.23

[0438] θM=78°

[0439] The data (RDN) of the projection optical system LM1 in Example 7 are shown in Table 49 below.

[0440] Table 49

[0441]

[0442] In Table 49, the lens surfaces with an asterisk (*) in the number column are aspherical. That is, the 12th, 13th, 26th, 27th, 37th, 38th, and 41st surfaces marked with an asterisk are aspherical. The parameters of each aspherical surface in the above formula (A1) are shown in Table 50 below.

[0443] Table 50

[0444] K -1.303 0 -12.995 61.812 -7.383 -8.399 -3.205 C4 -2.76627E-05 4.00463E-05 -1.15735E-05 -2.12544E-05 -3.47198E-06 -2.52885E-05 -4.75323E-06 C6 -1.64120E-07 -4.14003E-07 2.44992E-08 2.65459E-08 6.85495E-08 3.10026E-08 2.85458E-09 C8 -9.09803E-10 -1.80520E-10 1.96277E-10 4.11051E-10 -1.36948E-10 2.71852E-12 -1.66739E-12 C10 2.45343E-12 -6.33657E-12 -3.63885E-12 -3.59817E-12 0.00000E+00 -6.44863E-14 6.58584E-16 C12 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 -1.00600E-17 -1.67752E-19 C14 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 -2.29099E-20 2.36463E-23 C16 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 0.00000E+00 1.21713E-23 -1.47148E-27

[0445] Regarding D (interval) in Table 49, for surfaces marked with "S", displacement is achieved through focusing. During focusing, the displacements are as follows: "S27" between the first lens group G1 and the second lens group G2, "S32" between the second lens group G2 and the third lens group G3, and "S40" between the third lens group G3 and the reflector M1. Furthermore, the displacement between the reflector M1 and the screen surface is "S41". Since light is reflected, S41 is set to negative (-). Table 51 below shows how S27, S32, S40, and S41 are displaced. It should be noted that the distances to the screen are selected as close (approximately 100 inches), reference (approximately 125 inches), and far (approximately 150 inches) as references.

[0446] Table 51

[0447] close up 6.892 1.1 76.713 -430 benchmark 5.088 3.094 76.523 -533.87 long distance 3.796 4.498 76.41 -641.89

[0448] Furthermore, in the projection optical system LM1 of Embodiment 7, the horizontal and vertical dimensions of the display element P1 located on the side closest to the reduction are shown in Table 52 below.

[0449] Table 52

[0450] Longitudinal length 5.82mm Distance from the optical axis to the bottom edge of the display panel 1.313mm

[0451] Figure 52 This is a diagram illustrating an example of an image projected onto a flat screen during close-range projection (equivalent to approximately 100 inches) using the projection optical system LM1 based on Embodiment 7. Figure 53This is a diagram illustrating an example of an image projected onto a flat screen during reference projection (equivalent to approximately 125 inches) using the projection optical system LM1 of Embodiment 7. Figure 54 This is a diagram illustrating an example of an image projected onto a flat screen during long-distance projection (equivalent to approximately 150 inches) using the projection optical system LM1 based on Embodiment 7. Figure 52 , Figure 53 and Figure 54 Simulation results of the grid distortion grid on the near-field side (approximately 100 inches), the reference side (approximately 125 inches), and the far-field side (approximately 150 inches) are shown respectively. Figure 52 , Figure 53 and Figure 54 As shown, good corrections were performed in the projection optical system LM1 of Example 7.

[0452] Furthermore, in the projection optical system LM1 of Embodiment 7, the X and Y coordinates of the display element P1 are specified as shown in Table 53 below. It should be noted that, since it is symmetrical about the X-axis, the coordinates are specified only on one side.

[0453] Table 53

[0454] F1 -5.184 7.145 F2 -2.592 7.145 F3 0 7.145 F4 -5.184 5.687 F5 -2.592 5.687 F6 0 5.687 F7 -5.184 4.229 F8 -2.592 4.229 F9 0 4.229 F10 -5.184 2.771 F11 -2.592 2.771 F12 0 2.771 F13 -5.184 1.313 F14 -2.592 1.313 F15 0 1.313

[0455] Figure 55 This is a dot plot showing a near-field projection (equivalent to about 100 inches) of the projection optical system LM1 based on Embodiment 7. Figure 56 This is a dot plot showing the reference projection (equivalent to approximately 125 inches) of the projection optical system LM1 based on Embodiment 7. Figure 57 This is a dot plot showing the projection distance (approximately 150 inches) of the projection optical system LM1 based on Embodiment 7. These dot plots were simulated under the conditions shown in Table 53 above. Figure 55 , Figure 56 and Figure 57 As shown, good corrections were performed in the projection optical system LM1 of Example 7.

[0456] In addition, the parameters of the projection optical system LM1 in Embodiment 7 are shown in Table 54 below.

[0457] Table 54

[0458]

[0459] In the projection optical system LM1 of Embodiment 7, the values ​​of conditions (1)-(8) above are shown in Table 55 below. That is, in the projection optical system LM1 of Embodiment 7, conditions (1)-(8) above are satisfied respectively.

[0460] Table 55

[0461]

[0462] As described above, the projection optical system LM1 in Embodiment 7 is as follows: Figures 52-57 The sample has good optical properties and satisfies conditions (1)-(8).

Claims

1. A projection optical system for magnifying and projecting images or videos, wherein, The projection optical system includes: The refractive section comprises multiple lens groups; and The reflective part is composed of a concave mirror, which reflects the light that has passed through the refractive part. The plurality of lens groups includes a focal group and at least one fixed group, wherein the focal group is movable in response to changes in the projection size of the image or video. The focal group has two lens groups. When focusing, the two lens groups move along the optical axis with different displacements. The refractive section includes a plurality of lenses, the lens located on the magnification side, the second lens from the magnification side, and the third lens from the magnification side, each having a negative optical power. When the focal length of the projection optical system is set to F, and the focal length of the lens group located on the narrowest side among the multiple lens groups is set to F1, the following condition (5) is satisfied. (5) 7 <F1 / F<15。 2. The projection optical system according to claim 1, wherein, One of the two lens groups has positive optical power. The other of the two lens groups has a negative optical power.

3. The projection optical system according to claim 2, wherein, When the focal length of the lens group with positive optical power in the two lens groups is set to FP, and the focal length of the lens group with negative optical power in the two lens groups is set to FN, the following condition (1) is satisfied. (1) -2.5 <FN / FP<0.0。 4. The projection optical system according to claim 2 or 3, wherein, Regarding the lens group with positive optical power among the two lens groups, the amount of movement during focusing from the near distance side to the far distance side is denoted as FoP. Regarding the lens group with negative optical power in the two lens groups, when the amount of movement when focusing from the near distance side to the far distance side is set as FoN, the following condition (2) is satisfied. (2) 0.1 < |FoN / FoP| < 1.

0.

5. The projection optical system according to any one of claims 1 to 3, wherein, When the focal length of the lens located on the magnification side is set to LW1, and the focal length of the second lens from the magnification side is set to LW2, the following condition (3) is satisfied. (3) 0.9 <LW1 / LW2<6.0。 6. The projection optical system according to any one of claims 1 to 3, wherein, When the focal length of the third lens from the magnifying side is set to LW3, and the focal length of the fourth lens from the magnifying side among the plurality of lenses is set to LW4, the following condition (4) is satisfied. (4) -1.5 <LW3 / LW4<0.0。 7. The projection optical system according to any one of claims 1 to 3, wherein, The refractive part also includes an aperture. The aperture is located within the lens group that is closest to the narrowing side among the plurality of lens groups.

8. The projection optical system according to claim 7, wherein, Regarding the lens group located closest to the narrowing side, the focal length from the narrowing side to the aperture is set to F1-1. Regarding the lens group located at the position closest to the narrowing side, if the focal length from the aperture to the position closest to the magnification side is set to F1-2, the following condition (6) is satisfied. (6) 0.1 <F1-1 / F1-2<1.2。 9. The projection optical system according to any one of claims 1 to 3, wherein, The projection optical system is a reduced telecentric system.

10. The projection optical system according to any one of claims 1 to 3, wherein, The refractive section includes a first lens group with positive optical power, a second lens group with positive optical power, a third lens group with negative optical power, and a fourth lens group with negative optical power. In the projection optical system, the first lens group, the second lens group, the third lens group, the fourth lens group, and the reflective part are arranged sequentially from the side closest to the reduction in size.

11. The projection optical system according to any one of claims 1 to 3, wherein, The refractive section includes a first lens group with positive optical power, a second lens group with positive optical power, and a third lens group with negative optical power. In the projection optical system, the first lens group, the second lens group, the third lens group, and the reflective part are arranged sequentially from the side closest to the reduction in size.

12. A projector apparatus comprising the projection optical system according to any one of claims 1 to 11, wherein, The projection optical system also includes a light modulation element that modulates light from a light source to form image light. The image light passes through the projection optics system.

Images