Optical devices, projectors, and imaging devices

Abstract

To make optical devices more compact. [Solution] The optical device 50 comprises a first reflective surface 4a having power, a second reflective surface 4b having power and positioned on the enlarged side of the first reflective surface 4a, and a first optical element 42a positioned on the enlarged side of the second reflective surface 4b. The first optical element 42a has a first transmissive surface 5a arranged sequentially from the contraction side to the enlargement side, a third reflective surface 4c having a concave shape that reflects light inside the first optical element 42a, and a second transmissive surface 5b different from the first transmissive surface 5a. A first light absorbing member AB01 is positioned outside the effective light ray passage region EA4b on the second reflective surface 4b, and this first light absorbing member AB01 has an inclined surface that slopes outward from the corresponding second reflective surface 4b as it moves away from the corresponding second reflective surface 4b.

Description

[Technical Field]

[0001] The present invention relates to an optical device, and to a projector and imaging device equipped with an optical device. [Background technology]

[0002] As an imaging optical system for an imaging device, there is a known system that includes a block-shaped reflecting refractive element having two refractive surfaces and two reflective surfaces, wherein a shielding portion is provided in the region opposite each reflective surface between the incident light beam to each reflective surface and the reflected light beam from the reflective surface (Patent Document 1). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-106566 [Overview of the project] [Problems that the invention aims to solve]

[0004] In the imaging optical system of Patent Document 1, only light rays that pass through a wedge-shaped spatial region with a pointed cross-section that avoids a predetermined optical path facing the reflective surface are targeted for shielding. It is not easy to block stray light, which has various optical paths. In other words, light rays from unintended optical paths generated on or around the reflective surface may be reflected by, for example, the holding members of optical elements present in the optical system, and become stray light. [Means for solving the problem]

[0005] An optical device in one aspect of the present invention comprises a first reflective surface having power, a second reflective surface having power positioned on the enlarged side of the first reflective surface, a first optical element positioned on the enlarged side of the second reflective surface and arranged sequentially from the contraction side toward the enlargement side, having a first transmissive surface, a third reflective surface having power and a concave shape, and a second transmissive surface different from the first transmissive surface, and at least one light absorbing member from a first light absorbing member positioned outside the effective light ray passage region of the second reflective surface, and a second light absorbing member positioned outside the effective light ray passage region of the first reflective surface, wherein at least one light absorbing member has an inclined surface that slopes outward from the corresponding reflective surface as it moves away from the corresponding reflective surface.

[0006] In one aspect of the present invention, the projector comprises the optical device described above and an image forming unit that forms an image on the reduced-side conjugate surface of the optical device.

[0007] An imaging device in one aspect of the present invention comprises the optical device described above and an image sensor disposed on the conjugate surface of the optical device on the reduction side. [Brief explanation of the drawing]

[0008] [Figure 1] This diagram illustrates the structure of a projector incorporating the optical device of the first embodiment. [Figure 2] This diagram shows the projection state of the optical device onto the screen. [Figure 3] This is a cross-sectional view illustrating the optical device or projection optical system of Example 1. [Figure 4] This is a front view illustrating the first light-shielding member, which includes a third light-absorbing member. [Figure 5] This is a front view illustrating the second light-shielding member, which includes the first light-absorbing member. [Figure 6] The lateral aberration characteristics of the projection optical system of Example 1 are shown. [Figure 7] The lateral aberration characteristics of the projection optical system of Example 1 are shown. [Figure 8] This diagram illustrates the relationship between the display surface and the projection surface in Example 1. [Figure 9]It is a cross-sectional view for explaining the optical device or projection optical system of the second embodiment. [Figure 10] It is a front view for explaining the first light shielding member including the second light absorption member. [Figure 11] It is a front view for explaining the second light shielding member including the first light absorption member. [Figure 12] Shows the lateral aberration characteristics of the projection optical system of Example 2. [Figure 13] Shows the lateral aberration characteristics of the projection optical system of Example 2. [Figure 14] It is a diagram for explaining the relationship between the display surface and the projection surface of Example 2. [Figure 15] It is a diagram for explaining the structure of an imaging device incorporating the optical device of the third embodiment.

[0009] 〔First Embodiment〕 Hereinafter, with reference to the drawings, an optical device according to the first embodiment of the present invention and a projector incorporating the same will be described.

[0010] FIG. 1 is a diagram for explaining the structure of a projector 2 incorporating an optical device 50 according to the first embodiment. As shown in FIG. 1, the projector 2 includes an optical system portion 60 that projects image light and a circuit device 80 that controls the operation of the optical system portion 60. The optical system portion 60 has an image display device 20 that displays image light or video light and a projection optical system 40 that projects the image light onto a screen SC (see FIG. 2).

[0011] The image display device 20 has a light source device 10, a separation optical system 20a, an image forming portion 20b, and a prism PR. In the present embodiment, the optical device 50 is a projection optical device 51, which is a combination of the prism PR and the projection optical system 40.

[0012] The light source device 10 emits light including R light, G light, and B light in a homogenized state. The light source device 10 includes, for example, a light source lamp such as an ultra-high pressure mercury lamp, a two-stage integrator lens having a plurality of lens elements arranged in an array, a polarization conversion element that converts the light passing through the two-stage integrator lens into a predetermined linear polarization, and a superimposing lens that superimposes the illumination light emitted from the rear-stage integrator lens on the display areas of the liquid crystal panels 29R, 29G, and 29B.

[0013] The separation optical system 20a separates the light emitted from the light source device 10 into three colors of R, G, and B. The separation optical system 20a includes a first dichroic mirror 21, a second dichroic mirror 22, relay lenses 23 and 24, reflection mirrors 25, 26, and 27, and field lenses 28R, 28G, and 28B. The image forming unit 20b includes liquid crystal panels 29R, 29G, and 29B which are light modulation elements OM.

[0014] The first dichroic mirror 21 reflects the R light incident from the light source device 10 and transmits the G light and the B light. The R light reflected by the first dichroic mirror 21 is incident on the liquid crystal panel 29R through the reflection mirror 25 and the field lens 28R. The liquid crystal panel 29R forms an R-color image by modulating the R light according to the image signal.

[0015] The second dichroic mirror 22 reflects the G light from the first dichroic mirror 21 and transmits the B light. The G light reflected by the second dichroic mirror 22 is incident on the liquid crystal panel 29G through the field lens 28G. The liquid crystal panel 29G forms a G-color image by modulating the G light according to the image signal. The B light transmitted through the second dichroic mirror 22 is incident on the liquid crystal panel 29B through the relay lenses 23 and 24, the reflection mirrors 26 and 27, and the field lens 28B. The liquid crystal panel 29B forms a B-color image by modulating the B light according to the image signal. [[ID=#]]

[0016] The liquid crystal panels 29R, 29G, and 29B, which are the image forming units 20b, form an image on their display surfaces, that is, on the reduced conjugate plane RC of the projection optical system 40 (see Figure 3).

[0017] The prism PR is, for example, a cross dichroic prism 31. The cross dichroic prism 31 is a prism for photosynthesis, which synthesizes the light modulated by each liquid crystal panel 29R, 29G, and 29B to form image light, which is then directed to the projection optical system 40.

[0018] The projection optical system 40 is a projection lens that projects the image light, which is modulated by each liquid crystal panel 29R, 29G, and 29B and combined by the cross dichroic prism 31, onto the screen SC (see Figure 2).

[0019] The circuit device 80 includes an image processing unit 81 to which an external image signal IS such as a video signal is input, a display drive unit 82 that drives liquid crystal panels 29R, 29G, and 29B provided in the optical system section 60 based on the output of the image processing unit 81, a lens drive unit 83 that adjusts the state of the projection optical system 40 by operating a moving mechanism AN provided in the projection optical system 40, and a main control unit 88 that comprehensively controls the operation of these circuit sections 81, 82, 83, etc.

[0020] The image processing unit 81 converts the input external image signal IS into an image signal that includes the gradation of each color. The image processing unit 81 can also perform various image processing operations on the external image signal IS, such as distortion correction and color correction.

[0021] The display drive unit 82 can operate the liquid crystal panels 29R, 29G, and 29B based on the image signal output from the image processing unit 81, and can form an image on the liquid crystal panels 29R, 29G, and 29B that corresponds to the image signal or an image that has been processed therefrom.

[0022] The lens drive unit 83 operates under the control of the main control unit 88 and adjusts the focus of the projection optical system 40 by appropriately moving the lens 41 constituting the projection optical system 40 or optical device 50 along the optical axis OA of the device using the moving mechanism AN. Here, the optical axis OA of the device is the axis passing through the center of the lens 41 in the optical device 50, or the central axis OX passing through the center of the conjugate plane RC on the reduction side (see Figure 3). The moving mechanism AN includes, for example, an actuator.

[0023] The lens drive unit 83 can be omitted. In this case, the lens 41 may be manually moved using a mechanical mechanism including a cam mechanism as the moving mechanism AN, and the focus of the projection optical system 40 may be adjusted.

[0024] The optical device 50 will be described in detail below with reference to Figures 2 and 3. Figure 2 shows the projection state of the optical device 50 onto the screen SC. Figure 3 is a diagram illustrating the configuration of the optical device 50 and the light rays. Note that the optical device 50 illustrated in Figure 3 has the same configuration as the optical device 50 of Example 1, which will be described later.

[0025] As shown in Figure 2, the optical device 50 comprises a prism PR and a projection optical system 40. The optical device 50 projects the image formed on the display surface 2a or projection surface of the image forming unit 20b onto the projection surface 2b of the screen SC. In other words, the image light ML emitted from the display surface 2a of the image forming unit 20b passes through the prism PR and the projection optical system 40 and is incident on the projection surface 2b of the screen SC. Here, a prism PR corresponding to the cross dichroic prism 31 in Figure 1 is positioned between the projection optical system 40 and the image forming unit 20b.

[0026] As shown in Figure 3, the projection optical system 40 of the optical device 50 comprises a lens 41, an internal reflective element 42, and a mirror element 43. The projection optical system 40 is an eccentric or off-axis optical system, and the optical axis OA of the device, which extends along the optical path through the center of the image forming unit 20b, is arranged along a plane of symmetry parallel to the YZ plane. In other words, the projection optical system 40 is asymmetric with respect to the vertical Y direction and symmetric with respect to the YZ plane. The projection optical system 40 of the optical device 50 comprises, as a general set of components, a first reflective surface 4a having power, a second reflective surface 4b having power and positioned on the enlarged side of the first reflective surface 4a, and a first optical element 42a having a first transmissive surface 5a, a third reflective surface 4c having a concave shape that reflects light internally, and a second transmissive surface 5b different from the first transmissive surface 5a, which are positioned on the enlarged side of the second reflective surface 4b and arranged sequentially from the reduction side to the enlargement side. Furthermore, the projection optical system 40 includes a third optical element 42c having a fourth reflective surface 4d positioned on the enlarged side of the second reflective surface 4b in the optical path between the second reflective surface 4b and the first optical element 42a, and a fifth reflective surface 4e positioned between the fourth reflective surface 4d and the first transmissive surface 5a. Here, the third reflective surface 4c has positive power, and the fourth reflective surface 4d is spatially positioned on the contraction side conjugate surface RC side of the first reflective surface 4a and the third reflective surface 4c. As will be described in detail later, the first optical element 42a and the third optical element 42c are included in the internal reflective element 42. The internal reflective element 42 and mirror element 43 constituting the projection optical system 40 are held in the lens barrel member 49 shown in Figure 2 and are aligned with each other.

[0027] Lens 41 is a positive lens positioned between the retraction-side conjugate surface RC and the first reflective surface 4a of the optical device 50 or projection optical system 40. This allows the retraction side of the optical device 50 to be made telecentric. It also suppresses the spread of the light beam, allowing the entire optical system of the optical device 50 to be miniaturized. Note that telecentricity includes the case where the principal ray is approximately parallel to the optical axis OA of the device. Lens 41 can be moved along the lens optical axis OA2 or the central axis OX of the retraction-side conjugate surface RC by the movement mechanism AN. This enables a focusing function in the optical device 50.

[0028] The internal reflective element 42 has a first optical element 42a, a second optical element 42b, and a third optical element 42c. The first optical element 42a, the second optical element 42b, and the third optical element 42c are an integrated internal reflective element 42. The internal reflective element 42 is an internal reflective type refractive optical element that has both internal reflection and refraction functions in a single element. Since the first to third optical elements 42a to 42c are an integrated component, that is, composed of the same element, cost reduction and improved assembly accuracy can be achieved. As will be described in detail later, the internal reflective element 42 has one or more reflective surfaces that are internal reflective surfaces W1. The internal reflective element 42 is formed from a light-transmitting material. Examples of light-transmitting materials include resin and glass. The light-transmitting material is formed, for example, by molding.

[0029] The first optical element 42a is positioned on the magnifying or upper side of the internal reflective element 42. The first optical element 42a has a first transmissive surface 5a, a third reflective surface 4c having a concave shape in the direction of the incident light ray, and a second transmissive surface 5b different from the first transmissive surface 5a, arranged sequentially from the reduction side to the magnification side. In other words, in the first optical element 42a, and by extension the internal reflective element 42, the final reflective surface on the magnification side has a concave shape. The third reflective surface 4c is an internal reflective surface W1 that reflects or reflects light from the back surface inside the first optical element 42a. Because the first optical element 42a has a first transmissive surface 5a and a second transmissive surface 5b, the transmissive surface through which the incident light passes (incident surface) and the transmissive surface through which the emitted light passes (exit surface) are located in different regions of the first optical element 42a. This makes it possible to improve optical performance by giving separate functions to the first transmission surface 5a, which is the incident surface of the first optical element 42a, and the second transmission surface 5b, which is the exit surface.

[0030] A boundary, not shown, is provided between the first transmissive surface 5a and the second transmissive surface 5b, specifically a linear or strip-shaped boundary in which the curvature, etc., changes discontinuously. This boundary may be provided with a light-absorbing member to suppress the leakage of incident or reflected light to the first optical element 42a into an optical path outside the specified path and back into the specified optical path from another location.

[0031] In this embodiment, at least one of the first transmissive surface 5a, the third reflective surface 4c, and the second transmissive surface 5b has power. In this embodiment, the first transmissive surface 5a, the third reflective surface 4c, and the second transmissive surface 5b have positive power. This makes it possible to utilize the refractive power of the first transmissive surface 5a and the second transmissive surface 5b that are close to the third reflective surface 4c, which facilitates ray control and is advantageous for miniaturizing and improving the performance of the optical device 50. The sign of the power of the first transmissive surface 5a, the third reflective surface 4c, and the second transmissive surface 5b can be changed as appropriate, but it is preferable that the third reflective surface 4c and the second transmissive surface 5b have positive power.

[0032] In the optical device 50, an intermediate image is formed between the first transmission surface 5a and the third reflection surface 4c. In other words, the intermediate image is formed within the first optical element 42a. As a result, the intermediate image is formed in the optical path on the reduced side of the third reflection surface 4c, and by re-imaging the intermediate image with the concave third reflection surface 4c, it becomes possible to shorten the focal length.

[0033] The second optical element 42b is positioned on the reduced side or below the internal reflective element 42. The second optical element 42b has a first reflective surface 4a and a third transmissive surface 5c. The third transmissive surface 5c transmits both incident light incident on the first reflective surface 4a and reflected light reflected by the first reflective surface 4a. By having the incident and exit rays to the second optical element 42b pass through the third transmissive surface 5c, which is the same refractive surface W3, ray control that is not possible with surface reflection becomes possible, and optical performance can be improved in a space-saving manner.

[0034] A ring-shaped, three-dimensional third light-absorbing member AB03 is provided on the third transmissive surface 5c, surrounding it. A ring-shaped aperture diaphragm ST1 is provided on the first reflective surface 4a, surrounding it. The third light-absorbing member AB03 and the aperture diaphragm ST1 prevent light rays from unintended optical paths generated around or near them from bending into the optical path and becoming stray light. The third transmissive surface 5c and the first reflective surface 4a correspond to the aperture surfaces of the entire system, and the third light-absorbing member AB03 also functions as an aperture diaphragm.

[0035] The third optical element 42c is positioned in the internal reflective element 42 between the first optical element 42a and the second optical element 42b. The third optical element 42c has a fourth reflective surface 4d positioned on the enlarged side of the second reflective surface 4b of the mirror element 43, which will be described later.

[0036] A ring-shaped, three-dimensional fourth light-absorbing member AB04 is provided on the fourth reflective surface 4d, surrounding it. The fourth light-absorbing member AB04 prevents light rays from unintended optical paths generated around or near it from bending into the optical path and becoming stray light.

[0037] Figure 4 is a conceptual plan view illustrating the third light-absorbing member AB03 attached to the third transmissive surface 5c and the fourth light-absorbing member AB04 attached to the fourth reflective surface 4d, showing each member as viewed from the front of the third transmissive surface 5c and the fourth reflective surface 4d. The third light-absorbing member AB03 and the fourth light-absorbing member AB04 are connected to form a single first light-shielding member SM1, but they may remain separate and unconnected. The first light-shielding member SM1 may be manufactured as a single unit, or it may be integrated by individually manufacturing the third light-absorbing member AB03 and the fourth light-absorbing member AB04 and joining them together. The third light-absorbing member AB03 is fixed to the periphery of the third transmissive surface 5c using adhesive or a bonding agent, or fixed to the lens barrel member 49 (see Figure 2). The fourth light-absorbing member AB04 is fixed to the periphery of the fourth reflective surface 4d using an adhesive or glue, or it is fixed to the lens barrel member 49 (see Figure 2).

[0038] The third light-absorbing member AB03, on the other hand, is approximately circular overall. The third light-absorbing member AB03 has an annular inclined surface SS3 on its inside and a partially annular outer surface SO3, except for the portion that overlaps with the fourth light-absorbing member AB04. The third light-absorbing member AB03 and the fourth light-absorbing member AB04 are connected, and the boundary portion P1 is a common part of the third light-absorbing member AB03 and the fourth light-absorbing member AB04. In other words, the +Y side portion of the third light-absorbing member AB03 is consequently positioned between the effective light-passing region EA5c of the third transmission surface 5c and the effective light-passing region EA4d of the fourth reflection surface 4d. This boundary portion P1 suppresses stray light from unintended optical paths generated on the third transmission surface 5c, the fourth reflection surface 4d, and their surroundings. The lower end or bottom inner edge of the inclined surface SS3 coincides with the outer edge of the effective light-passing region EA5c of the third transmission surface 5c. The inclined surface SS3 and the outer surface SO3 are both smooth, continuous curved surfaces that touch each other at their upper ends away from the third transmissive surface 5c (i.e., corresponding to the -Z side shown in Figure 3), forming a knife-ridge-like apex. The inclined surface SS3 is set to have the same angle of passage as the effective light rays passing through the third transmissive surface 5c. In the illustrated example, the inclined surface SS3 is inclined outward from the corresponding third transmissive surface 5c as it moves away from the corresponding third transmissive surface 5c. Here, the inclination of the inclined surface SS3 is based on the concave third transmissive surface 5c, and although it appears to be inclined inward in the drawing, when based on the normals at each position of the third transmissive surface 5c, it is inclined outward from the third transmissive surface 5c at the tip (see the cross-sectional view in Figure 3). When the optical device 50 is used as a projection optical device 51, the light emitted from the liquid crystal panel 29G or the like, which is a display device, is restricted by the third light absorbing member AB03 in the initial stage of the optical system, thereby preventing unnecessary diffuse reflection within the optical system of the optical device 50. In particular, by positioning the inclined surface SS3 to surround the corresponding third transmissive surface 5c, unwanted light that causes stray light can be blocked not only in the eccentric or off-axis direction, but also in the direction perpendicular thereto.The third light-absorbing member AB03 is three-dimensional, and the inclined surface SS3 on the inside of the third light-absorbing member AB03 follows the contour shape of the light beam, which is a combination of the image light ML incident on the third transmissive surface 5c toward the first reflecting surface 4a and the image light ML passing through the third transmissive surface 5c toward the second reflecting surface 4b. If the inclined surface SS3 follows the outer shape of the light beam that is incident on and emitted in this way, the effect of suppressing unwanted light generated on and around the corresponding third transmissive surface 5c is enhanced. Furthermore, the inclined surface SS3 of the third light-absorbing member AB03 indirectly corresponds to the effective light ray passage region of the first reflecting surface 4a, and follows the contour shape of the light beam that is reflected by the first reflecting surface 4a and passes through the third transmissive surface 5c.

[0039] The third light-absorbing member AB03 is made of, for example, aluminum. More specifically, the third light-absorbing member AB03 is formed of aluminum, and the inclined surface SS3 and the outer surface SO3 are anodized. The third light-absorbing member AB03, made of aluminum with an anodized surface, has high shape accuracy, high heat resistance, and minimal accuracy degradation even under strong light rays.

[0040] The third light-absorbing member AB03 may, for example, have a main body made of various metals, with the inclined surface SS3 and outer surface SO3 treated with black baked paint. A metal third light-absorbing member AB03 has high heat resistance and high shape accuracy.

[0041] The third light-absorbing member AB03 may, for example, have a main body made of metal or heat-resistant resin, with a light-absorbing film placed on the surface of the inclined surface SS3 or the outer surface SO3. In this case, the light-absorbing film is fixed to the surface of the inclined surface SS3 or the outer surface SO3 by an adhesive or the like. If the third light-absorbing member AB03 is made of metal, its durability is increased, and if the third light-absorbing member AB03 is made of heat-resistant resin, it is relatively inexpensive and easy to process. The light-absorbing film on the surface can be formed from a light-absorbing material, but the light absorption performance can be improved by, for example, forming a microstructure on the surface. The third light-absorbing member AB03 may be entirely made of a light-absorbing resin material.

[0042] The fourth light-absorbing member AB04 of the first light-shielding member SM1 is generally rectangular in shape. The fourth light-absorbing member AB04 has an inner rectangular frame-shaped inclined surface SS4 and an outer surface SO4 that is partially rectangular frame-shaped except for the portion that overlaps with the third light-absorbing member AB03. The lower end or inner edge of the bottom of the inclined surface SS4 coincides with the outer edge of the effective light-passing region EA4d of the fourth reflective surface 4d. Both the inclined surface SS4 and the outer surface SO4 are smooth, continuous curved surfaces that touch each other at their upper ends away from the fourth reflective surface 4d, forming a knife-ridge-like apex. The inclined surface SS4 is inclined outward from the corresponding fourth reflective surface 4d as it moves away from it. Here, the inclination of the inclined surface SS4 is based on the slightly convex fourth reflective surface 4d, and is inclined outward from the fourth reflective surface 4d at the tip (see cross-sectional view in Figure 3). By positioning the inclined surface SS4 to surround the corresponding fourth reflective surface 4d, unwanted light that causes stray light can be blocked not only in the eccentric or off-axis direction, but also in the direction perpendicular thereto. The fourth light absorbing member AB04 is three-dimensional, and the inclined surface SS4 on the inside of the fourth light absorbing member AB04 follows the contour shape of the light beam, which is a combination of the image light ML incident on the fourth reflective surface 4d and the image light ML reflected by the fourth reflective surface 4d. If the inclined surface SS4 follows the outer shape of the light beam that is incident on and reflected in this way, the effect of suppressing unwanted light generated on and around the corresponding fourth reflective surface 4d is enhanced.

[0043] Of the fourth light-absorbing member AB04, the outer surface SO4 at the +Y side end has a surface shape that does not obstruct the path of the image light ML that is reflected by the fifth reflective surface 4e and incident on the first transmissive surface 5a.

[0044] The fourth light-absorbing member AB04 is made of, for example, aluminum. More specifically, the fourth light-absorbing member AB04 is formed of aluminum, and the inclined surface SS4 and the outer surface SO4 are anodized.

[0045] The fourth light-absorbing member AB04 may, for example, have a main body made of various metals, with the inclined surface SS4 and the outer surface SO4 having a black baked coating applied to their surfaces.

[0046] The fourth light-absorbing member AB04 may, for example, have a main body made of metal or heat-resistant resin, with a light-absorbing film placed on the surface of the inclined surface SS4 or the outer surface SO4. In this case, the light-absorbing film is fixed to the surface of the inclined surface SS4 or the outer surface SO4 by an adhesive or the like.

[0047] The fourth light-absorbing member AB04 is not limited to a three-dimensional structure as shown in the figure, but can also be in the form of a thin film or a sheet.

[0048] Referring to Figure 3, in the internal reflective element 42, a light-absorbing member ABB for light shielding can be attached to the back surface 6a so as to cover the entire back surface 6a sandwiched between the first reflective surface 4a and the third reflective surface 4c.

[0049] The mirror element 43 is spatially positioned in the -Z direction relative to the internal reflective element 42, that is, on the contraction-side conjugate plane RC side. The mirror element 43 has a second reflective surface 4b and a fifth reflective surface 4e. The second and fifth reflective surfaces 4b and 4e are surface reflective surfaces W4 that reflect incident light off the surface of the mirror element 43. The second and fifth reflective surfaces 4b and 4e face the internal reflective element 42 at a position closer to the center, avoiding the upper and lower ends of the internal reflective element 42. In other words, the second and fifth reflective surfaces 4b and 4e are spatially positioned on the contraction-side conjugate plane RC side relative to the third reflective surface 4c. The second reflective surface 4b is spatially positioned on the lower side of the optical device 50, that is, on the contraction side. Furthermore, the second reflective surface 4b is positioned between the third transmission surface 5c and the fourth reflective surface 4d in the optical path. The fifth reflective surface 4e is positioned on the upper side of the optical device 50, that is, on the expansion side. Furthermore, the fifth reflective surface 4e is positioned between the fourth reflective surface 4d and the first transmissive surface 5a in the optical path. The mirror element 43 is integrally formed such that the fifth and second reflective surfaces 4e and 4b are arranged vertically. This makes it possible to miniaturize and reduce the cost of the optical system of the optical device 50. The substrate of the mirror element 43 is made of, for example, resin, metal, etc.

[0050] A stepped boundary is provided between the second reflective surface 4b and the fifth reflective surface 4e. On one of the second reflective surfaces 4b, a ring-shaped, three-dimensional first light absorbing member AB01 is provided so as to surround it. On the other fifth reflective surface 4e, a ring-shaped, three-dimensional fifth light absorbing member AB05 is provided so as to surround it. The first light absorbing member AB01 and the fifth light absorbing member AB05 prevent light rays from unintended optical paths generated around or near them from bending into the optical path and becoming stray light.

[0051] Figure 5 is a conceptual plan view illustrating the first light-absorbing member AB01 attached to the second reflective surface 4b and the fifth light-absorbing member AB05 attached to the fifth reflective surface 4e, showing each member as viewed from the front of the second reflective surface 4b and the fifth reflective surface 4e. The first light-absorbing member AB01 and the fifth light-absorbing member AB05 are connected to form a single second light-shielding member SM2, but they may remain separate and not connected. The second light-shielding member SM2 may be manufactured as a single unit, or it may be integrated by individually manufacturing the first light-absorbing member AB01 and the fifth light-absorbing member AB05 and joining them together. The first light-absorbing member AB01 is fixed to the periphery of the second reflective surface 4b using adhesive or a bonding agent. The fifth light-absorbing member AB05 is fixed to the periphery of the fifth reflective surface 4e using adhesive or a bonding agent.

[0052] The first light-absorbing member AB01 is roughly rectangular in shape. The first light-absorbing member AB01 has an inner rectangular frame-shaped inclined surface SS1 and an outer surface SO1 that is partially rectangular frame-shaped, except for the portion that overlaps with the fifth light-absorbing member AB05. The first light-absorbing member AB01 and the fifth light-absorbing member AB05 are connected, and the boundary portion P2 is a common portion of the first light-absorbing member AB01 and the fifth light-absorbing member AB05. In other words, the +Y side portion of the first light-absorbing member AB01 is consequently positioned between the effective light-passing region EA4b of the second reflective surface 4b and the effective light-passing region EA4e of the fifth reflective surface 4e. This boundary portion P2 suppresses stray light from unintended optical paths generated on the second reflective surface 4b, the fifth reflective surface 4e, and their surroundings. The lower end or bottom inner edge of the inclined surface SS1 coincides with the outer edge of the effective light-passing region EA4b of the second reflective surface 4b. The inclined surface SS1 and the outer surface SO1 are both smooth, continuous curved surfaces that touch each other at their upper ends away from the second reflective surface 4b, forming a knife-ridge-like apex. The inclined surface SS1 is inclined outward from the corresponding second reflective surface 4b as it moves away from it. Here, the inclination of the inclined surface SS1 is based on the slightly convex second reflective surface 4b, and is inclined outward from the second reflective surface 4b at the tip (see cross-sectional view in Figure 3). By providing the inclined surface SS1 to surround the corresponding second reflective surface 4b, unwanted light that causes stray light can be blocked not only in the eccentric or off-axis direction, but also in the direction perpendicular thereto. The first light absorbing member AB01 is three-dimensional, and the inclined surface SS1 on the inside of the first light absorbing member AB01 follows the contour shape of the light beam, which is the sum of the image light ML incident on the second reflective surface 4b and the image light ML reflected by the second reflective surface 4b. If the inclined surface SS1 follows the shape of the outer contour of the incident and reflected light beam, the effect of suppressing unwanted light generated on the corresponding second reflective surface 4b and its surroundings is enhanced.

[0053] Referring to Figure 3, the outer surface SO1 at the -Y side end of the first light absorbing member AB01 has a surface shape that does not obstruct the path of the image light ML that passes through the lens 41 and heads toward the first reflective surface 4a.

[0054] Returning to Figure 5, the first light-absorbing member AB01 is made of, for example, aluminum. More specifically, the first light-absorbing member AB01 is formed of aluminum, and the inclined surface SS1 and the outer surface SO1 are anodized.

[0055] The first light-absorbing member AB01 may, for example, have a main body made of various metals, with the inclined surface SS1 and the outer surface SO1 having a black baked coating applied to their surfaces.

[0056] The first light-absorbing member AB01 may, for example, have a main body made of metal or heat-resistant resin, with a light-absorbing film placed on the surface of the inclined surface SS1 or the outer surface SO1. In this case, the light-absorbing film is fixed to the surface of the inclined surface SS1 or the outer surface SO1 by an adhesive or the like.

[0057] The fifth light-absorbing member AB05 of the second light-shielding member SM2 is generally rectangular in shape. The fifth light-absorbing member AB05 has an inner rectangular frame-shaped inclined surface SS5 and an outer surface SO5 that is partially rectangular frame-shaped except for the portion that overlaps with the first light-absorbing member AB01. The lower end or inner edge of the bottom of the inclined surface SS5 coincides with the outer edge of the effective light-passing region EA4e of the fifth reflective surface 4e. Both the inclined surface SS5 and the outer surface SO5 are smooth, continuous curved surfaces that touch each other at their upper ends away from the fifth reflective surface 4e, forming a knife-ridge-like apex. The inclined surface SS5 is inclined outward from the corresponding fifth reflective surface 4e as it moves away from it. Here, the inclination of the inclined surface SS5 is based on the slightly concave fifth reflective surface 4e, and at the tip end, it is inclined outward from the fifth reflective surface 4e (see cross-sectional view in Figure 3). By positioning the inclined surface SS5 to surround the corresponding fifth reflective surface 4e, unwanted light that causes stray light can be blocked not only in the eccentric or off-axis direction, but also in the direction perpendicular thereto. The fifth light absorbing member AB05 is three-dimensional, and the inclined surface SS5 on the inside of the fifth light absorbing member AB05 follows the contour shape of the light beam, which is a combination of the image light ML incident on the fifth reflective surface 4e and the image light ML reflected by the fifth reflective surface 4e. If the inclined surface SS5 follows the outer shape of the light beam that is incident on and reflected in this way, the effect of suppressing unwanted light generated on and around the corresponding fifth reflective surface 4e is enhanced.

[0058] The fifth light-absorbing member AB05 is made of, for example, aluminum. More specifically, the fifth light-absorbing member AB05 is formed of aluminum, and the inclined surface SS5 and the outer surface SO5 are anodized.

[0059] The fifth light-absorbing member AB05 may, for example, have a main body made of various metals, with the inclined surface SS5 and the outer surface SO5 having a black baked coating applied to their surfaces.

[0060] The fifth light-absorbing member AB05 may, for example, have a main body made of metal or heat-resistant resin, with a light-absorbing film placed on the surface of the inclined surface SS5 or the outer surface SO5. In this case, the light-absorbing film is fixed to the surface of the inclined surface SS5 or the outer surface SO5 by an adhesive or the like.

[0061] The fifth light-absorbing member AB05 is not limited to a three-dimensional structure as shown in the figure, but can also be in the form of a thin film or a sheet.

[0062] Focusing on the optical surfaces of the internal reflective element 42 and the mirror element 43, the optical device 50 has, in the optical path, a third transmitting surface 5c, a first reflecting surface 4a, a third transmitting surface 5c, a second reflecting surface 4b, a fourth reflecting surface 4d, a fifth reflecting surface 4e, a first transmitting surface 5a, a third reflecting surface 4c, and a second transmitting surface 5b, in the order from the reduction side to the expansion side. In the optical device 50, the image light ML is reflected five times. By providing the optical device 50 with a plurality of reflecting surfaces 4a to 4e in a direction that projects magnified with respect to the central axis OX of the reduction-side conjugate surface RC, which is the reduction-side imaging surface, the reflection angle can be minimized and a decrease in optical performance can be suppressed.

[0063] Furthermore, when focusing on the optical surface of the internal reflective element 42 in a cross-sectional view, the third transmissive surface 5c, the fourth transmissive surface 4d, the first transmissive surface 5a, and the second transmissive surface 5b are arranged on the side of the internal reflective element 42 that is the conjugate surface RC, i.e., the second reflective surface 4b side. On the side of the internal reflective element 42 opposite to the conjugate surface RC, i.e., the first reflective surface 4a side, the back surface 6a and the third reflective surface 4c are arranged. In this way, in the projection optical system 40 of the embodiment, the internal reflective surface W1, the surface reflective surface W2, and the refractive surface W3 can be arranged three-dimensionally on the internal reflective element 42 while maintaining their functions. Specifically, they can be arranged side by side in the vertical Y direction and spaced appropriately apart in the front-to-back Z direction, which is advantageous for miniaturization. Specifically, the internal reflective surface W1 corresponds to the first and third reflective surfaces 4a and 4c. The surface reflective surface W2 corresponds to the fourth reflective surface 4d. The refractive surface W3 corresponds to the first to third transmission surfaces 5a to 5c.

[0064] In the internal reflective element 42, the internal reflective surface W1 and the surface reflective surface W2 may have a thin metal film such as aluminum or silver formed on their surface, or a dielectric multilayer film formed on their surface. The refractive surface W3 has an anti-reflective film formed on its surface. On the contraction side conjugate surface RC of the internal reflective element 42, the surface reflective surface W2 and the refractive surface W3 are provided on a continuous surface, and the reflective film constituting the surface reflective surface W2 and the anti-reflective film constituting the refractive surface W3 are formed in corresponding regions.

[0065] In the mirror element 43, the surface reflective surface W4 may be a reflective surface with a thin metal film such as aluminum or silver formed on its surface, or a reflective surface with a dielectric multilayer film formed on its surface.

[0066] The optical path of the optical device 50 will be described below. Image light from the image forming unit 20b passes through the prism PR and lens 41 and enters the third transmission surface 5c of the internal reflection element 42. The light that has passed through the third transmission surface 5c is refracted as appropriate and internally reflected by the first reflection surface 4a. The light reflected by the first reflection surface 4a passes through the third transmission surface 5c again. The light emitted from the third transmission surface 5c and refracted as appropriate is reflected by the second reflection surface 4b of the mirror element 43. The light reflected by the second reflection surface 4b is surface-reflected by the fourth reflection surface 4d of the internal reflection element 42 and reflected by the fifth reflection surface 4e of the mirror element 43. The light reflected by the fifth reflection surface 4e enters the first transmission surface 5a of the internal reflection element 42. The light that has passed through the first transmission surface 5a is refracted as appropriate and internally reflected by the third reflection surface 4c. Light reflected by the third reflective surface 4c passes through the second transmissive surface 5b, which is different from the first transmissive surface 5a. The light emitted from the second transmissive surface 5b and refracted as appropriate is projected onto the screen SC (see Figure 2).

[0067] The optical device 50 described above comprises a first reflective surface 4a having power, a second reflective surface 4b having power and positioned on the enlarged side of the first reflective surface 4a, and a first optical element 42a positioned on the enlarged side of the second reflective surface 4b. The first optical element 42a has a first transmissive surface 5a arranged sequentially from the contraction side to the enlargement side, a third reflective surface 4c having a concave shape that reflects light inside the first optical element 42a, and a second transmissive surface 5b different from the first transmissive surface 5a. At least one of the first transmissive surface 5a, the third reflective surface 4c, and the second transmissive surface 5b has power.

[0068] In the optical device 50 described above, by utilizing the refractive power of the first and second transmission surfaces 5a and 5b, which are close to the third reflection surface 4c, which is the inner reflection surface W1 of the first optical element 42a, ray control becomes easier, which is advantageous for miniaturization and high performance. Furthermore, the first and second transmission surfaces 5a and 5b can be given different functions to the incident and exit surfaces of the first optical element 42a, thereby improving optical performance. In addition, by making the third reflection surface 4c the inner reflection surface W1, the third reflection surface 4c can be made smaller, and the entire optical system can be miniaturized. As a result of the above, the optical device 50 can be made shorter in focal length and miniaturized.

[0069] Conventionally, when a projection optical system is composed solely of refractive elements, the number of lenses increases to correct for the spherical shape of the lenses and chromatic aberration, resulting in a linear projection lens with a long overall length. In contrast, the optical device 50 of the present invention can realize a three-dimensional optical system by utilizing multiple reflective surfaces and multiple refractive surfaces. Furthermore, since the internal reflective element 42 utilizes a molded reflective surface, it is not limited to a spherical shape, and by effectively utilizing the correction function of aspherical or free-form shapes on each surface, a projection system can be realized with a small number of surfaces and parts. As a result, the overall length of the optical system (i.e., the dimension in the Z direction) can be shortened, and a configuration in which the image is folded back towards the image forming unit 20b can be realized. In particular, when the focal length is shortened, the main body of the device can be placed near the screen SC, realizing a user-friendly projection configuration.

[0070] Furthermore, if the projection optical system is constructed using only surface reflective elements, as in conventional methods, the projection optical system becomes a large optical system with a large number of reflective surfaces. In contrast, the optical device 50 of the present invention uses an internal reflective element 42, which is an internal reflective type refractive optical element, and by utilizing the refractive effect at the transmission interface, the number of reflective surfaces can be reduced, thereby realizing a compact optical system.

[0071] In particular, by making the final reflective surface on the magnification side, specifically the third reflective surface 4c, a concave shape, the intermediate image formed in front of the third reflective surface 4c can be magnified and projected, thereby achieving wide-angle projection. Furthermore, the first light absorbing member AB01 is positioned outside the effective light ray passage region EA4b of the second reflective surface 4b, and this first light absorbing member AB01 has an inclined surface that slopes outward from the corresponding second reflective surface 4b as it moves away from the corresponding second reflective surface 4b. This prevents stray light from unintended optical paths generated around the second reflective surface 4b from bending into the optical path and becoming stray light, without obstructing the optical path of the target light ray.

[0072] Furthermore, the optical device 50 can be made into a single component by arranging the optical elements or optical surfaces together in the vertical direction and connecting each element. Since the shapes of multiple surfaces can be manufactured at once by integral molding of the optical elements, it is possible to realize an optical system that reduces the number of parts while ensuring assembly accuracy.

[0073] As described above, the optical device 50 is a compact device that is bright, produces high image quality, and has a wide angle of view.

[0074] The projector 2 described above comprises the optical device 50 and an image forming unit 20b that forms an image on the reduction-side conjugate surface RC of the optical device 50. This makes it possible to miniaturize the projector 2 equipped with the optical device 50.

[0075] [Examples] The following describes an embodiment of the optical device 50.

[0076] In the following examples, including Example 1, the displacement z of the surface on an aspherical surface is determined by the following polynomial (aspherical equation). TIFF2026109015000002.tif16166 However, c: Curvature (1 / R) h: Height from the optical axis k: Conic coefficient Ai: i-th order aspherical coefficients

[0077] The displacement z of a surface in an XY polynomial surface is determined by the following polynomial. TIFF2026109015000003.tif16166 However, c: Curvature (1 / R) k: Conic coefficient C mn :monomial x m y n coefficient r: Radial distance (r = √(x 2 +y 2 ))

[0078] (Example 1) Table 1 shows the optical surface data for Example 1. The terms used in Table 1 and the following tables are defined below. Surface number 1 refers to the reducing conjugate surface RC, and the last surface number refers to the expanding conjugate surface MC. "TC" means to refer to the eccentricity setting table. Data for surface numbers that do not correspond to the optical elements shown in Figure 3 are dummy data. SuNo: Face Number SuTy: Surface type Mt:Material SuFu: Surface function (refractory or reflective) SP: Spherical NP: Aspherical XY-FS:XY polynomial surface INF:Infinity OM1:SBSL7_OHARA OM2: Refractive index; 1.516745, Abbe number; 67.43 OM3:Z-330R DK: Refractive surface RH: Reflective surface R: paraxial curvature radius (unit: mm) D: Spacing on the shaft (unit: mm) Ar: Opening radius (unit: mm)

[0079] [Table 1] SuNo SuTy RD Mt SuFu Ar 1 SP INF 9.5000 DK 7.5472 2 SP INF 25.9100 OM1 DK 9.2096 3 SP INF 0.1000 DK 12.3490 4 NP 28.8770 6.9428 OM2 DK 12.8011 5 NP 47.6057 1.4383 DK 13.0167 6 SP INF TC DK 13.4207 7 NP -94.0326 TC OM3 DK 56.3488 8 NP -118.4506 TC OM3 RH 24.6180 9 NP -94.0326 TC DK 61.1608 10 XY-FS-96.6316 TC RH 34.1892 11 XY-FS 116.8783 TC RH 70.2483 12 XY-FS 291.7526 TC RH 58.1977 13 NP 41.5495 TC OM3 DK 40.5669 14 NP -63.1738 TC OM3 RH 25.6137 15 NP 24.5897 TC DK 24.1499 16 SP INF 0.0000 DK 112.8491 17 SP INF -608.6860 DK 112.8491 18 SP INF 0.0000 DK 998.8233

[0080] Table 2 shows the eccentricity settings for Example 1. The terms used in Table 2 and the following tables are defined below. The X-axis is the axis perpendicular to the plane of the paper, with the depth direction being positive. α rotation is the clockwise rotation around the X-axis when observed in the +X direction. The unit of distance is mm, and the unit of angle is °. Ec: Eccentricity XEc:X eccentricity YEc: Y-eccentricity ZEc:Z eccentricity αRo: α rotation Nr: Normal N / A: None DC & RE: Decenter and Return

[0081] [Table 2] CoNo Ec XEc YEc ZEc αRo 1 nr - - - - 2 N / A - - - - 3 N / A - - - - 4 N / A - - - - 5 N / A - - - - 6 dc & re - - 3.0000 - 7 dc & re - -37.3662 30.9474 -40.3930 8 dc & re - -4.1776 80.0000 -11.8012 9 dc & re - -37.3662 30.9474 -40.3930 10 dc & re - 46.7505 0.0000 15.4661 11 dc & re - -2.8256 62.0106 20.7235 12 dc & re - 81.6189 0.0000 -5.6859 13 dc & re - 100.5863 34.3353 1.4988 14 dc & re - 100.5863 80.0000 1.4988 15 dc & re - 100.5863 34.3353 1.4988 16 nr - - 80.0000 -

[0082] Table 3 shows the aspherical data for Example 1. The terms used in Table 3 and the following tables are defined below. Each item in the table is written in two rows. In Table 3 and the following tables, powers of 10 (e.g., 1.00 × 10) +18 This is expressed using E (for example, 1.00E+18). A: Fourth-order aspherical coefficients B: Sixth-order aspherical coefficients C: 8th-order aspherical coefficient [Table 3] SuNo 4 5 7 8 9 13 14 15 R 28.8770 47.6057 -94.0326 -118.4506 -94.0326 41.5495 -63.1738 24.5897 k 0 0 -4.56456798 -0.806373821 -4.56456798 -1.130497264 -1.223810266 0.0163858628 A -2.33958E-05 -8.62465E-06 -6.59366E-07 -6.44513E-08 -6.59366E-07 1.92800E-06 1.79185E-06 1.62137E-06 B -1.74199E-08 -2.81549E-08 5.14391E-11 -2.99274E-12 5.14391E-11 -6.00051E-10 -2.33459E-10 1.06802E-09 C -2.50049E-11 7.67102E-12 -6.52695E-15 1.45230E-15 -6.52695E-15 -3.50419E-15 -2.98931E-13 1.23508E-11

[0083] Table 4 shows the XY polynomial surface data for Example 1. In Table 4 and the following tables, C-xmyn is x m yn The coefficient C of the term (where m and n are integers greater than or equal to 0) mn is meant. When m or n is 0, or for x m or y n it is 1 and not shown.

[0084] [Table 4] SuNo 10 11 12 R -96.6316 116.8783 291.7526 k -0.0772 0.7438 16.6250 C-x4 -2.90007E-07 1.06165E-06 1.05110E+⁰¹ C-x2y2 -5.09409E-08 -2.36731E-06 1.84650E+⁰¹ C-y4 -1.67407E-07 -2.56278E-07 7.90174E+⁰⁰ C-x6 9.59623E-10 -4.03104E-10 -1.02890E+⁰¹ C-x4y2 3.17737E-10 1.51031E-10 -2.47269E+⁰¹ C-x2y4 2.14788E-10 5.34443E-10 -2.43574E+⁰¹ C-y6 1.04278E-10 -9.22891E-11 -6.86895E+⁰⁰ C-x8 2.58292E-13 -7.24293E-13 6.67097E+⁰⁰ C-x6y2 -1.46208E-12 1.64145E-13 2.55089E+⁰¹ C-x4y4 -2.13827E-13 -9.37039E-14 3.24116E+⁰¹ C-x2y6 -2.19981E-13 -4.83831E-14 2.12806E+⁰¹ C-y8 -5.24404E-14 1.92004E-14 3.70168E+⁰⁰ C-x10 0 1.86064E-15 7.98339E-⁰¹ Note: In scientific notation, the "⁰" in the exponent part is used to represent the power of 10 for better display in the translation. In the original text, it should be standard scientific notation like "E+01", etc.C-x8y2 0 -1.3112E-16 -1.53734E+01 C-x6y4 0 2.60133E-17 -2.31288E+01 C-x4y6 0 7.50031E-18 -2.05257E+01 C-x2y8 0 3.65135E-19 -1.08005E+01 C-y10 0 -1.46754E-18 -1.36452E+00

[0085] Figure 3 is a cross-sectional view of the optical device 50 of Example 1.

[0086] The optical device 50 includes a prism PR, a lens 41, an internal reflective element 42, and a mirror element 43. The internal reflective element 42 is an integrated unit comprising a first optical element 42a, a second optical element 42b, and a third optical element 42c. The third optical element 42c is positioned between the first optical element 42a and the second optical element 42b. The mirror element 43 is positioned opposite the internal reflective element 42.

[0087] The first optical element 42a has a first transmission surface 5a, a third reflection surface 4c, and a second transmission surface 5b. The third reflection surface 4c is a concave inner reflection surface W1. In the first optical element 42a, the refractive surfaces W3 through which incident and reflected light pass are different optical surfaces for the first transmission surface 5a and the second transmission surface 5b. The first transmission surface 5a, the third reflection surface 4c, and the second transmission surface 5b have positive power.

[0088] The second optical element 42b has a first reflective surface 4a and a third transmissive surface 5c. The first reflective surface 4a is a concave inner surface reflective surface W1. In the second optical element 42b, the refractive surface W3 through which incident light and reflected light pass is a single third transmissive surface 5c, which is a common optical surface. An aperture diaphragm ST1 is placed on the first reflective surface 4a. A third light absorbing member AB03 is placed on the third transmissive surface 5c.

[0089] The third optical element 42c has a fourth reflective surface 4d, which is the surface reflective surface W2. The back surface 6a, which is the surface opposite to the fourth reflective surface 4d, is generally smooth but is not an optical surface. A fourth light absorbing member AB04 is placed on the fourth reflective surface 4d, and a light absorbing member ABB is placed on the back surface 6a.

[0090] The mirror element 43 has a second reflective surface 4b, which is a surface reflective surface W4, and a fifth reflective surface 4e, which is also a surface reflective surface W4. The second and fifth reflective surfaces 4b and 4e are integrated. A first light absorbing member AB01 is placed on the second reflective surface 4b, and a fifth light absorbing member AB05 is placed on the fifth reflective surface 4e.

[0091] The optical device 50 has, in the optical path, a third transmissive surface 5c, a first reflective surface 4a, a third transmissive surface 5c, a second reflective surface 4b, a fourth reflective surface 4d, a fifth reflective surface 4e, a first transmissive surface 5a, a third reflective surface 4c, and a second transmissive surface 5b, in the order from the reduction side to the expansion side. In the internal reflective element 42, the third transmissive surface 5c, the fourth reflective surface 4d, the first transmissive surface 5a, and the second transmissive surface 5b are arranged on the reduction side conjugate surface RC side, that is, on the second reflective surface 4b side. On the opposite side of the internal reflective element 42 from the reduction side conjugate surface RC, that is, on the first reflective surface 4a side, the back surface 6a and the third reflective surface 4c are arranged.

[0092] Figures 6 and 7 show the lateral aberration characteristics of the optical device 50 or projection optical system 40 of Example 1. Figure 8 is a diagram illustrating the relationship between the display surface 2a of the liquid crystal panel 29G and the projection surface 2b of the screen SC of Example 1. In the upper part of Figure 8, the ● marks indicate the position of light rays on the display surface 2a, and in the lower part of Figure 8, the ● marks indicate the position of light rays on the projection surface 2b. The coordinates shown in Figure 8 are based on the center of the display surface 2a or the center of the projection surface 2b. Since the light ray positions are symmetrical, the lateral aberration diagram shows the characteristics of nine points on one side corresponding to the coordinates on the display surface 2a.

[0093] The optical device 50 of the first embodiment shown in Figure 3, etc., is not limited to the illustrated structure, and various modifications are possible within the scope of the gist of the invention.

[0094] The first reflective surface 4a may be a surface reflective surface, in which case the third transmissive surface 5c is omitted. In this case, the second light absorbing member AB02 (see Figure 10), which will be described later, can be provided on the surface of the first reflective surface 4a.

[0095] [Second Embodiment] The optical apparatus of the second embodiment will now be described. Note that the optical apparatus of the second embodiment is a modified version of the optical apparatus of the first embodiment, and the parts common to both embodiments will not be described.

[0096] Figure 9 shows the configuration and ray diagram of the optical device 50. Note that the optical device 50 illustrated in Figure 9 has the same configuration as the optical device 50 of Embodiment 2 described later.

[0097] As shown in Figure 9, in this embodiment, the mirror element 43 has a second reflective surface 4b as one surface reflective surface W4. Also, the optical device 50 does not have a third optical element 42c as shown in Figure 3, etc. Furthermore, although the details will be described later, the lens 41 is eccentric. Because the lens 41 is eccentric, in the example of Figure 9, the lens 41 has the shape of only the upper half of a circular lens shape into which light rays are incident.

[0098] The internal reflective element 42 has a first optical element 42a and a second optical element 42b.

[0099] The first optical element 42a has a first transmissive surface 5a, a third reflective surface 4c which is an inner reflective surface W1, and a second transmissive surface 5b. The second optical element 42b has a first reflective surface 4a which is a surface reflective surface W2. A second light absorbing member AB02 is arranged on the first reflective surface 4a. The first reflective surface 4a is positioned at or near the pupil position of the entire system and functions as an aperture diaphragm.

[0100] Figure 10 is a conceptual plan view illustrating the second light-absorbing member AB02 provided in conjunction with the first reflective surface 4a, showing the member as viewed from the front of the first reflective surface 4a. The second light-absorbing member AB02 constitutes the first light-shielding member SM1 on its own. The second light-absorbing member AB02 is fixed to the periphery of the first reflective surface 4a using adhesive or a bonding agent.

[0101] The second light-absorbing member AB02 is approximately circular overall. The second light-absorbing member AB02 has an annular inclined surface SS2 on the inside and an annular outer surface SO2 on the outside. The second light-absorbing member AB02 suppresses stray light from unintended optical paths generated around the first reflective surface 4a and their surroundings. The lower end or bottom inner edge of the inclined surface SS2 coincides with the outer edge of the effective light-passing region EA4a of the first reflective surface 4a. Both the inclined surface SS2 and the outer surface SO2 are smooth, continuous curved surfaces that touch each other at their upper ends away from the first reflective surface 4a (i.e., corresponding to the -Z side shown in Figure 9), forming a knife-ridge-like apex. The inclined surface SS2 is inclined outward from the corresponding first reflective surface 4a as it moves away from the corresponding first reflective surface 4a. Here, the inclination of the inclined surface SS2 is based on the concave first reflective surface 4a, and at the tip side, it is inclined outward from the first reflective surface 4a (see the cross-sectional view in Figure 9). By positioning the inclined surface SS2 to surround the corresponding first reflective surface 4a, unwanted light that causes stray light can be blocked not only in the eccentric or off-axis direction, but also in the direction perpendicular thereto. The second light absorbing member AB02 is three-dimensional, and the inclined surface SS2 on the inside of the second light absorbing member AB02 follows the contour shape of the light beam, which is a combination of the image light ML incident on the first reflective surface 4a and the image light ML reflected by the first reflective surface 4a. If the inclined surface SS2 follows the outer shape of the light beam that is incident on and reflected in this way, the effect of suppressing unwanted light generated on and around the corresponding first reflective surface 4a is enhanced.

[0102] Above the second light-absorbing member AB02, i.e., on the +Y side, the outer surface SO2 is positioned to lie along the large step difference between the first transmissive surface 5a and the first reflective surface 4a.

[0103] The second light-absorbing member AB02 is made of, for example, aluminum. More specifically, the second light-absorbing member AB02 is formed of aluminum, and the inclined surface SS2 and the outer surface SO2 are anodized.

[0104] The second light-absorbing member AB02 may, for example, have a main body made of various metals, with the inclined surface SS2 and the outer surface SO2 having a black baked coating treatment.

[0105] The second light-absorbing member AB02 may, for example, have a main body made of metal or heat-resistant resin, with a light-absorbing film placed on the surface of the inclined surface SS2 or the outer surface SO2. In this case, the light-absorbing film is fixed to the surface of the inclined surface SS2 or the outer surface SO2 by an adhesive or the like.

[0106] As illustrated in Figure 9, a fourth light-absorbing member AB4 may be provided at the boundary between the first transmissive surface 5a and the second transmissive surface 5b to suppress incident or reflected light to the first optical element 42a from leaking into an unspecified optical path and returning to the specified optical path from another location.

[0107] In the internal reflective element 42, a light-shielding light-absorbing member ABB can be attached to the back surface 6a so as to cover the entire back surface 6a sandwiched between the first reflective surface 4a and the third reflective surface 4c.

[0108] Since the mirror element 43 consists only of the second reflective surface 4b, it can be miniaturized. A light-absorbing member AB01 is placed on the second reflective surface 4b as the second light-shielding member ST2.

[0109] Figure 11 is a conceptual plan view illustrating the first light-absorbing member AB01 provided in conjunction with the second reflective surface 4b, showing the member as viewed from the front of the second reflective surface 4b. The first light-absorbing member AB01 constitutes the second light-shielding member SM2 on its own. The first light-absorbing member AB01 is fixed to the periphery of the second reflective surface 4b using adhesive or a bonding agent.

[0110] The first light-absorbing member AB01 is substantially rectangular in shape. The first light-absorbing member AB01 has a rectangular frame-shaped inclined surface SS1 on the inside and a rectangular frame-shaped inclined surface S01 on the outside. The first light-absorbing member AB01 suppresses stray light from unintended optical paths generated around the second reflective surface 4b and their surroundings. The structure and function of the first light-absorbing member AB01 are the same as those described in the first embodiment with reference to Figure 5, etc., and will not be described here.

[0111] Referring to Figure 9, the optical axis OA2 of lens 41 is shifted on the opposite side of the enlargement-side conjugate plane MC (see Figure 2) corresponding to the screen SC, relative to the center of the display device (specifically, the liquid crystal panel 29G, etc.), the display surface 2a, or the center of the reduction-side conjugate plane RC. The optical axis OA2 is defined by the axis connecting the centers of the spheres of the incident and exit surfaces of lens 41. In other words, lens 41 is shifted downward, or in the -Y direction, in the vertical direction which is the Y direction perpendicular to the central axis OX passing through the center of the reduction-side conjugate plane RC or the reduction-side image plane. This allows the position of the first reflective surface 4a to be placed on the lower side, opposite to the enlargement-side conjugate plane MC or the enlargement-side image plane, relative to the central axis OX of the reduction-side conjugate plane RC, and reduces the height of the optical system positioned above the first reflective surface 4a.

[0112] In the above, focusing on the optical surface of the internal reflective element 42, the optical device 50 has, in the optical path, a first reflective surface 4a, a second reflective surface 4b, a first transmitting surface 5a, a third reflective surface 4c, and a second transmitting surface 5b, in the order from the reduction side to the expansion side. In the optical device 50, the image light is reflected three times.

[0113] (Example 2) Table 5 shows the optical surface data for Example 2. The terms used in Table 5 are defined below. OM1=SBSL7_OHARA OM3=Z-330R OM6 = refractive index; 1.487490, Abbe number; 70.41 [Table 5] SuNo SuTy RD Mt SuFu Ar 1 SP INF 9.5000 DK 7.5472 2 SP INF 25.9100 OM1 DK 9.7316 3 SP INF 2.0000 DK 13.7947 4 SP INF 1.7952 DK 29.5718 5 NP -305.9334 4.4443 OM6 DK 29.8081 6 NP -106.1521 0.1000 DK 29.9102 7 SP INF TC DK 30.0793 8 XY-FS -153.7023 TC RH 34.0569 9 XY-FS -76.1137 TC RH 51.6330 10 NP 42.5040 TC OM3 DK 45.1329 11 XY-FS -57.3718 TC OM3 RH 53.8924 12 NP 350.6869 TC DK 48.1930 13 SP INF TC DK 169.8454 14 SP INF -428.0000 DK 169.8454 15 SP INF 0.0000 DK 773.3410

[0114] Table 6 shows the eccentricity settings for Example 2. [Table 6] CoNo Ec XEc YEc ZEc αRo 1 nr - - - - 2 N / A - - - - 3 N / A - - - - 4 nr - -20.3152 - - 5 N / A - - - - 6 N / A - - - - 7 dc & re - - 3.0000 - 8 dc & re - - 119.4592 -16.1328 9 dc & re - 93.4176 0.0000 36.2218 10 dc & re - 93.2930 52.2173 -8.1585 11 dc & re - 125.7550 117.3741 32.8682 12 dc & re - 93.2930 52.2173 -14.6886 13 nr - - 52.2173 - 14 dc & re - - - - 15 N / A - - - -

[0115] Table 7 shows the aspherical data for Example 2. The terms used in Table 7 are defined below. A: Fourth-order aspherical coefficients B: Sixth-order aspherical coefficients C: 8th-order aspherical coefficient D: 10th-order aspherical coefficient [Table 7] SuNo 5 6 10 12 R -0.0033 -0.0094 0.0235 0.0029 k -3.059334E+02 -1.061521E+02 4.250405E+01 3.506869E+02 A 0.000000E+00 0.000000E+00 -3.232399E-01 4.502167E+01 B 2.767998E-06 1.772463E-06 -1.711107E-06 2.614078E-06 C -1.877724E-09 -1.464826E-09 5.830137E-10 -6.789367E-10 D 4.69008E-13 2.98425E-13 -1.64402E-13 1.55824E-13

[0116] Table 8 shows the XY polynomial surface data for Example 2. [Table 8] SuNo 8 9 11 R -153.7022973 -76.11373632 -57.37178972 k -1.75E+00 -7.84E-01 -9.13E-01 C-x4 -6.14447E-08 -5.04573E-07 5.97035E-07 C-x2y2 -1.22579E-07 3.84921E-09 -3.71172E-06 C-y4 -6.15013E-08 -1.97105E-06 -2.14479E-07 C-x6 -2.24865E-13 -9.47912E-10 -1.74977E-09 C-x4y2 -1.57103E-12 6.46022E-10 -2.12943E-10 C-x2y4 -1.33344E-12 1.71838E-10 4.27392E-10 C-y6 -4.48952E-13 4.56109E-10 -2.64272E-10 C-x8 -6.52794E-17 8.18747E-13 1.26535E-12 C-x6y2 1.80997E-16 2.97945E-13 1.57809E-12 C-x4y4 1.7432E-16 -2.73843E-13 4.5708E-13 C-x2y6 -5.70596E-17 -5.6652E-14 1.80449E-13 C-y8 -6.55454E-18 -4.82723E-14 6.16036E-14

[0117] Figure 9 is a cross-sectional view of the optical device 50 of Example 2.

[0118] The optical device 50 includes a prism PR, a lens 41, an internal reflective element 42, and a mirror element 43. The internal reflective element 42 is an integrated first optical element 42a and a second optical element 42b. The mirror element 43 is positioned opposite the internal reflective element 42.

[0119] The first optical element 42a has a third reflective surface 4c, a first transmissive surface 5a, and a second transmissive surface 5b. The third reflective surface 4c is a concave inner surface reflective surface W1. In the first optical element 42a, the refractive surfaces W3 through which incident and reflected light pass are different for the first transmissive surface 5a and the second transmissive surface 5b. The first transmissive surface 5a, the third reflective surface 4c, and the second transmissive surface 5b have positive power.

[0120] The second optical element 42b has a first reflective surface 4a. The first reflective surface 4a is a concave surface reflective surface W2. A second light absorbing member AB02 is positioned on the first reflective surface 4a.

[0121] The mirror element 43 has a second reflective surface 4b, which is a surface reflective surface W4. The second reflective surface 4b is a convex surface reflective surface W4. The first light absorbing member AB01 is placed on the second reflective surface 4b.

[0122] The optical device 50 has a first reflective surface 4a, a second reflective surface 4b, a first transmitting surface 5a, a third reflective surface 4c, and a second transmitting surface 5b in the optical path, in the order from the reduction side to the expansion side. The first reflective surface 4a, the first transmitting surface 5a, and the second transmitting surface 5b are arranged on the reduction side conjugate surface RC side of the internal reflective element 42, that is, on the second reflective surface 4b side. The third reflective surface 4c is arranged on the opposite side of the reduction side conjugate surface RC of the internal reflective element 42, that is, on the opposite side of the first reflective surface 4a.

[0123] Figures 12 and 13 show the lateral aberration characteristics of the optical device 50 or projection optical system 40 of Example 2. Figure 14 is a diagram illustrating the relationship between the display surface 2a of the liquid crystal panel 29G and the projection surface 2b of the screen SC of Example 2.

[0124] The optical device 50 of the second embodiment shown in Figure 9, etc., is not limited to the illustrated structure and can be modified in various ways within the scope of the gist of the invention.

[0125] The first reflective surface 4a may also be a back surface reflective surface, in which case a third transmissive surface 5c, as shown in Figure 3, is added.

[0126] [Third Embodiment] The optical apparatus of the third embodiment will be described below. Note that the optical apparatus of the third embodiment is a partial modification of the optical apparatus of the first embodiment, and the parts common to the optical apparatus of the first embodiment will not be described.

[0127] Figure 15 is a diagram illustrating a camera 102 incorporating an optical device 150 according to the third embodiment. As shown in Figure 15, the camera 102 includes an optical system portion 60 that images the subject OB, and a circuit device 80 that controls the operation of the optical system portion 60. The optical system portion 60 includes an imaging optical system 140 that forms an image of the subject OB, and an image detection device 120 that detects the image.

[0128] The image detection device 120 has an image sensor 129. The image sensor 129 is positioned on the reduction-side conjugate surface RC of the optical device 150. In this embodiment, the optical device 150 is an imaging optical device 151. The optical device 150 illustrated in Figure 15 has the same configuration as the optical device 50 of Example 1 (see Figure 3, etc.). Alternatively, the optical device 150 may be the optical device 50 of Example 2 (see Figure 9, etc.). The imaging optical device 151 omits the prism PR that constitutes the optical device 50 of Examples 1 and 2, or replaces it with a cover glass that is not shown.

[0129] The optical device 150 forms an image of the subject OB using the imaging optical system 140 and acquires the image detected by the imaging surface 2c of the image sensor 129.

[0130] [Other matters] The structure described above is an example, and can be modified in various ways as long as similar functionality can be achieved.

[0131] For example, in each embodiment, the optical device 50 may have one or more substantially powerless lenses added to it.

[0132] Furthermore, the optical device 50 can project images not only formed by the liquid crystal panels 29R, 29G, and 29B, but also images formed by optical modulation elements such as digital micromirror devices.

[0133] Furthermore, the second light-absorbing member AB02, etc., may be omitted.

[0134] The optical devices 50 and 150 can be incorporated not only into projectors 2, but also into head-up displays, in-vehicle projection systems, and the like.

[0135] [Summary of this disclosure] A summary of this disclosure is provided below.

[0136] (Note 1) A first reflective surface that possesses power, A second reflective surface having power is positioned on the enlarged side of the first reflective surface, A first optical element having a first transmissive surface, a third reflective surface with a concave shape and power, and a second transmissive surface different from the first transmissive surface, arranged in order from the contraction side to the expansion side of the second reflective surface, A light absorbing member comprising at least one of the following: a first light absorbing member disposed outside the effective light ray passage region of the second reflective surface, and a second light absorbing member disposed outside the effective light ray passage region of the first reflective surface, Equipped with, The at least one light-absorbing member has an inclined surface that slopes outward from the corresponding reflective surface as it moves away from the corresponding reflective surface. optical equipment. The first and second transmitting surfaces allow the incident and exit surfaces of the first optical element to have different functions, thereby improving optical performance. Furthermore, by making the third reflecting surface an internal reflecting surface, the size of the third reflecting surface can be reduced, allowing for miniaturization of the entire optical system. As a result, it is possible to achieve a shorter focal length for the optical device and to miniaturize the optical device. In addition, the first or second light absorbing member, which is inclined toward the outside of the corresponding reflecting surface, prevents stray light from unintended optical paths generated around the second or first reflecting surface or its vicinity from bending into the optical path without obstructing the optical path of the target light ray.

[0137] (Note 2) In the optical apparatus described in Appendix 1, The inclined surface is provided so as to surround the corresponding reflective surface. optical equipment. In this way, by surrounding the corresponding reflective surface, unwanted light that causes stray light can be blocked not only in the eccentric or off-axis direction, but also in the direction perpendicular to it.

[0138] (Note 3) In the optical apparatus described in Appendix 2, The optical device is characterized in that the inclined surface has a shape in plan view that follows the outer shape of the light beam incident on and reflected by the corresponding reflective surface. If the inclined surface follows the shape of the outer contour of the light beam that is incident on and reflected, the effect of suppressing unwanted light generated at the corresponding reflective surface is enhanced.

[0139] (Note 4) In an optical device described in any one of the appendices 1 to 3, The system comprises both the first light-absorbing member and the second light-absorbing member, optical equipment.

[0140] (Note 5) In the optical device described in any one of the appendices 1 to 3, The above second light-absorbing member and, A fourth reflective surface is positioned on the enlarged side of the second reflective surface, A fifth reflective surface is positioned between the fourth reflective surface and the first transmissive surface, Furthermore, A portion of the second light-absorbing member is positioned between the effective light-passing region of the second reflective surface and the effective light-passing region of the fifth reflective surface. optical equipment. In this case, it is possible to suppress the stray light from the fifth reflecting surface and from unintended optical paths generated around it.

[0141] (Note 6) In the optical apparatus described in Appendix 5, A second optical element having a first reflective surface and a third transmissive surface through which both incident light incident on the first reflective surface and reflected light reflected by the first reflective surface are transmitted. A third light-absorbing member is positioned outside the effective light-passing region of the third transmissive surface, Furthermore, optical equipment. In this case, the third light-absorbing member can suppress stray light from unintended optical paths generated on or around the third transmission surface.

[0142] (Note 7) In the optical apparatus described in Appendix 6, A portion of the third light-absorbing member is positioned between the effective light-passing region of the third transmissive surface and the effective light-passing region of the fourth reflective surface. optical equipment. In this case, it is possible to suppress the stray light from the fourth reflecting surface and from unintended optical paths generated around it.

[0143] (Note 8) In an optical device described in any one of the appendices 1 to 7, The at least one light-absorbing member is made of aluminum, The surface of the inclined surface is treated with anodizing. optical equipment. Light-absorbing components made of aluminum with an anodized surface offer high shape precision, high heat resistance, and minimal precision degradation even under strong light.

[0144] (Note 9) In an optical device described in any one of the appendices 1 to 7, The at least one light-absorbing member is made of metal, The surface of the aforementioned inclined surface is treated with baked paint. optical equipment.

[0145] (Note 10) In an optical device described in any one of the appendices 1 to 7, The at least one light-absorbing member is made of metal or heat-resistant resin. A light-absorbing film is placed on the surface of the inclined surface. optical equipment. Light-absorbing materials made of resin are highly durable, and light-absorbing materials made of heat-resistant resin are relatively inexpensive and easy to process. For light-absorbing films, the light-absorbing performance can be enhanced by forming a microstructure on the surface.

[0146] (Note 11) In an optical device described in any one of the appendices 1 to 10, An intermediate image is formed between the first transmission surface and the third reflection surface. optical equipment. This creates an intermediate image in the optical path on the reduced side of the concave third reflecting surface, and by re-imaging this intermediate image with the third reflecting surface, it becomes possible to shorten the focal length.

[0147] (Note 12) In an optical device described in any one of the appendices 1 to 11, The first and second transparent surfaces have power. optical equipment.

[0148] (Note 13) In an optical device described in any one of the appendices 1 to 12, The system further comprises a positive lens positioned between the conjugate surface on the reduction side and the first reflective surface. optical equipment. This allows for telecentricity on the reduction side. Furthermore, it suppresses the spread of the light beam, enabling miniaturization of the entire optical system.

[0149] (Note 14) In the optical apparatus described in Appendix 13, The optical axis of the aforementioned lens is shifted to the opposite side of the conjugate plane from the center of the conjugate plane on the reducing side, relative to the conjugate plane on the expanding side. optical equipment. This allows the first reflecting surface to be positioned on the lower side, opposite to the enlargement-side conjugate surface, relative to the central axis of the reduction-side conjugate surface, thereby reducing the height of the optical system positioned above the first reflecting surface.

[0150] (Note 15) An optical device described in any one of the appendices 1 to 14, The optical device comprises an image forming unit that forms an image on the reduced-side conjugate surface, Equipped with, projector. This makes it possible to miniaturize projectors equipped with optical devices while suppressing the generation of stray light.

[0151] (Note 16) An optical device described in any one of the appendices 1 to 14, An image sensor arranged on the reduced conjugate surface of the optical device, Equipped with, Imaging device. This makes it possible to miniaturize imaging devices equipped with optical devices while suppressing the generation of stray light. [Explanation of Symbols]

[0152] 2...Projector, 2a...Display surface, 2b...Projection surface, 2c...Imaging surface, 4a~4e...Reflective surface, 5a~5c...Transmitting surface, 10...Light source device, 20...Image display device, 20a...Separation optical system, 20b...Image forming unit, 29R,29G,29B...Liquid crystal panel, 31...Cross dichroic prism, 40...Projection optical system, 41...Lens, 42,142,145...Internal reflection element, 42a,42b,42c...Optical element, 43...Mirror element, 50...Optical device, 51...Projection optical device, 60...Optical system section, 80...Circuit device, 102...Camera, 120...Image detection device, 129...Imaging sensor, 140...Imaging optical system, 150...Optics Device, 151…Imaging optical device, AB1~AB4…Light absorbing member, AN…Movement mechanism, MC…Magnification side conjugate surface, OA…Device optical axis, OA2…Lens optical axis, OB…Subject, OM…Light modulation element, OX…Central axis, PR…Prism, RC…Reduction side conjugate surface, SC…Screen, ST1…Aperture diaphragm, AB01…First light absorbing member, AB02…Second light absorbing member, AB03…Third light absorbing member, SS1,SS2,SS3…Inclined surface, SM1…First light shielding member, SM2…Second light shielding member, W1…Inner surface reflective surface, W2,W4…Surface reflective surface, W3…Refracting surface, EA4a,EA4b,EA4d,EA4e,EA5c…Effective light ray passage region

Claims

1. A first reflective surface that possesses power, A second reflective surface having power is positioned on the enlarged side of the first reflective surface, A first optical element having a first transmissive surface, a third reflective surface with a concave shape and power, and a second transmissive surface different from the first transmissive surface, arranged in order from the contraction side toward the enlargement side of the second reflective surface, A light absorbing member comprising at least one of the first light absorbing member and the second light absorbing member, which are located outside the effective light ray passage region of the second reflective surface, Equipped with, The at least one light-absorbing member has an inclined surface that slopes outward from the corresponding reflective surface as it moves away from the corresponding reflective surface. optical equipment.

2. In the optical apparatus described in claim 1, The inclined surface is provided so as to surround the corresponding reflective surface. optical equipment.

3. In the optical apparatus described in claim 2, The optical device is characterized in that the inclined surface has a shape in plan view that follows the outer shape of the light beam incident on and reflected by the corresponding reflective surface.

4. In the optical apparatus according to either claim 1 or 2, The system comprises both the first light-absorbing member and the second light-absorbing member, optical equipment.

5. In the optical apparatus according to either claim 1 or 2, The first light-absorbing member and, A fourth reflective surface is positioned on the enlarged side of the second reflective surface, A fifth reflective surface is disposed between the fourth reflective surface and the first transmissive surface, Furthermore, A portion of the first light-absorbing member is positioned between the effective light-passing region of the second reflective surface and the effective light-passing region of the fifth reflective surface. optical equipment.

6. In the optical apparatus described in claim 5, A second optical element having a first reflective surface and a third transmissive surface through which both incident light incident on the first reflective surface and reflected light reflected by the first reflective surface are transmitted. A third light-absorbing member is positioned outside the effective light-passing region of the third transmissive surface, Furthermore, optical equipment.

7. In the optical apparatus according to claim 6, A portion of the third light-absorbing member is positioned between the effective light-passing region of the third transmissive surface and the effective light-passing region of the fourth reflective surface. optical equipment.

8. In the optical apparatus according to either claim 1 or 2, The at least one light-absorbing member is made of aluminum, The surface of the inclined surface is treated with anodizing. optical equipment.

9. In the optical apparatus according to either claim 1 or 2, The at least one light-absorbing member is made of metal, The surface of the aforementioned inclined surface is treated with baked paint. optical equipment.

10. In the optical apparatus according to either claim 1 or 2, The at least one light-absorbing member is made of metal or heat-resistant resin. A light-absorbing film is placed on the surface of the inclined surface. optical equipment.

11. In the optical apparatus according to either claim 1 or 2, An intermediate image is formed between the first transmission surface and the third reflection surface. optical equipment.

12. In the optical apparatus according to either claim 1 or 2, The first and second transparent surfaces have power. optical equipment.

13. In the optical apparatus according to either claim 1 or 2, The system further comprises a positive lens positioned between the conjugate surface on the reduction side and the first reflective surface. optical equipment.

14. In the optical apparatus according to claim 13, The optical axis of the aforementioned lens is shifted to the opposite side of the conjugate plane from the center of the conjugate plane on the reducing side, relative to the conjugate plane on the expanding side. optical equipment.

15. The optical apparatus according to claim 1, The optical device comprises an image forming unit that forms an image on the reduced-side conjugate surface, Equipped with, projector.

16. The optical apparatus according to claim 1, An image sensor arranged on the reduced conjugate surface of the optical device, Equipped with, Imaging device.

Images