Optical module and head-mounted display device

Abstract

To provide an optical module or the like that has an improved optical performance.SOLUTION: An optical module 100 comprises: video elements 11a, 11b; a prism mirror 22 that reflects video light ML emitted from the video elements 11a, 11b on an internal reflection surface 22b; combiners 103a, 103b that reflect the video light ML from the prism mirror 22 toward pupil positions; and a barrel 31 that is arranged between the prism mirror 22 and the combiners 103a, 103b and determines a position of the prism mirror 22. The barrel 31 has first positioning surfaces 52a, 52b that are in contact with the prism mirror 22 in a second direction y1 parallel to the normal of a second virtual plane VP2 perpendicular to a first virtual plane VP1 and on which the video light ML emitted from an emission surface of the prism mirror 22 is incident, and a second positioning surface 52c that is in contact with the prism mirror 22 in a third direction z1 perpendicular to a first direction x1 and intersecting the second direction y1.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to an optical module that enables observation of a virtual image and a head-mounted display device equipped with the optical module. to Regarding. [Background technology]

[0002] A head-mounted display device that enables viewing of virtual images includes a plurality of prisms incorporating oblique incidence mirrors, and image light from an imaging element is incident on the user's eyes via a zigzag optical path due to reflection by the mirrors (see Patent Document 1). In this device, when assembling a first prism and a second prism, two first connectors and two second connectors are used to prevent misalignment of the assembled position of the second prism relative to the second prism. For example, the first connector is a connector provided on the first prism and has a convex portion, and the second connector is a connector provided on the second prism and has a concave portion (see Figure 8 of Patent Document 1, etc.). The first prism and the second prism are aligned by fitting the convex portions of the first connectors into the corresponding concave portions of the second connectors. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-333098 Summary of the Invention [Problem to be solved by the invention]

[0004] In the device of Patent Document 1, alignment is performed by fitting a convex portion into a concave portion, and a gap inevitably forms between these portions, causing misalignment. If the accuracy of the alignment between the prisms decreases in this way, there is a risk that the optical performance of the display device will deteriorate. [Means for solving the problem]

[0005] An optical module or a head-mounted display device according to one aspect of the present invention includes: Emits image light A video element; The aforementioned Video light an incident surface onto which the image light is incident, an exit surface from which the incident image light is emitted, and From the incident surface and a reflecting surface that reflects the image light toward the exit surface. a first reflecting optical member, and a second reflecting optical member for reflecting the image light from the first reflecting optical member toward a pupil position; to make a second reflective optical member; In the optical path of the image light, Disposed between the first reflecting optical member and the second reflecting optical member a first limiting surface, a second limiting surface facing the first limiting surface in a first direction, a pair of first positioning surfaces contacting the first reflecting optical member in a second direction intersecting the first direction, and a second positioning surface contacting the first reflecting optical member in a third direction perpendicular to the first direction and intersecting the second direction. a support member; The pair of first positioning surfaces are spaced apart in the first direction and have flat surfaces that extend perpendicular to the first direction and the second direction. .

[0006] In one aspect of the present invention, there is provided a method for manufacturing an optical module including: an imaging element; a first reflective optical member that causes imaging light emitted from the imaging element to enter through an incident surface, be reflected by an internal reflective surface, and exit through an exit surface; a second reflective optical member that reflects the imaging light from the first reflective optical member toward a pupil position; and a support member that is disposed between the first and second reflective optical members and positions the first reflective optical member, wherein the first reflective optical member is oriented in a direction that intersects with the optical axis of the imaging light that enters the incident surface when viewed from a first direction that is parallel to a normal to a first imaginary plane that includes the optical axis of the imaging light that enters the incident surface and the optical axis of the imaging light that exits from the exit surface. The support member has a first limiting surface and a second limiting surface facing the first reflecting optical member in a first direction, and the support member has a first positioning surface that contacts the first reflecting optical member in a second direction that is perpendicular to the first imaginary plane and parallel to the normal of a second imaginary plane on which the image light that is output from the output surface of the first reflecting optical member is incident, and a second positioning surface that contacts the first reflecting optical member in a third direction that is perpendicular to the first direction and intersects with the second direction, and the first reflecting optical member is positioned by fitting using the first limiting surface and the second limiting surface, and by offsetting using the first positioning surface and the second positioning surface. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is an external perspective view illustrating a state in which an HMD according to an embodiment is worn. [Figure 2] 1 shows a perspective view of the HMD main body and a perspective view of the inside with the exterior member removed. [Figure 3] 1A and 1B show a plan view and a left side view of an optical module. [Figure 4] FIG. 2 is a conceptual cross-sectional side view illustrating the optical system inside the HMD. [Figure 5] 10A and 10B are diagrams illustrating correction of distortion of a display image. [Figure 6] FIG. 2 is a side cross-sectional view illustrating the arrangement relationship of optical elements that configure the first optical system. [Figure 7] 10A and 10B are diagrams illustrating the positioning of a prism mirror relative to a barrel. [Figure 8] 1A and 1B are diagrams illustrating a barrel, a prism mirror, etc. [Figure 9] 5A and 5B are diagrams illustrating the positioning of a projection lens relative to a prism mirror. [Figure 10] 4A and 4B are diagrams illustrating the positioning of lenses in a projection lens. [Figure 11] FIG. 10 is a diagram illustrating the positioning of a combiner relative to a frame. [Figure 12] FIG. 10 is a plan view illustrating the positioning of the combiner relative to the frame. [Figure 13] FIG. 10 is a side cross-sectional view illustrating an optical module according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0008] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the optical module and head-mounted display device according to the present invention will be described with reference to the drawings.

[0009] FIG. 1 is a diagram illustrating a wearing state of an image display device 200. The image display device 200 is a head-mounted display device, i.e., a head-mounted display (hereinafter also referred to as HMD) 201, and allows an observer or wearer US wearing the image display device to recognize an image as a virtual image. In FIG. 1 and other figures, X, Y, and Z represent a Cartesian coordinate system, with the +X direction corresponding to the lateral direction in which the eyes EY of the observer or wearer US wearing the image display device 200 or HMD 201 are aligned, the +Y direction corresponding to the upward direction perpendicular to the lateral direction in which the eyes EY are aligned for the wearer US, and the +Z direction corresponding to the forward or front direction for the wearer US. The ±Y directions are parallel to the vertical axis or vertical direction.

[0010] The image display device 200 includes a main body 200a arranged to cover the eyes of the wearer US, and a pair of temple-shaped support devices 200b that support the main body 200a. From a functional perspective, the main body 200a includes a first display device 100a for the right eye and a second display device 100b for the left eye. The first display device 100a is composed of a first display driver 102a arranged on the top and a first combiner 103a shaped like a pair of glasses that covers the eyes. Similarly, the second display device 100b is composed of a second display driver 102b arranged on the top and a second combiner 103b shaped like a pair of glasses that covers the eyes.

[0011] The structure of the main body 200a of the image display device 200 will be described with reference to Fig. 2. In Fig. 2, an area AR1 is an external perspective view of the main body 200a, and an area AR2 is a perspective view in which the upper part of the main body 200a is exposed.

[0012] The pair of display drivers 102a, 102b located on the +Y side, i.e., the upper side, of main body 200a are connected and integrated, and are covered by a dome-shaped upper exterior member 107a that is elongated in the horizontal direction and a flat, plate-shaped lower exterior member 107b. First combiner 103a and second combiner 103b have a shape like a hemisphere with the top cut off and protruding forward, i.e., in the +Z direction, and are arranged to protrude downward from lower exterior member 107b.

[0013] The first display device 100a for the right eye includes a first image element 11a, a first optical system 12a, a first frame 61a, and a first combiner 103a. The first optical system 12a is covered by a first cover member 71a, which is an inner cover. The first image element 11a is disposed so as to cover an opening 71o of the first cover member 71a, and is fixed to the first optical system 12a via a rectangular frame-shaped first holder 72a. The first image element 11a and the first optical system 12a correspond to a first display driver 102a.

[0014] The second display device 100b for the left eye includes a second image element 11b, a second optical system 12b, a second frame 61b, and a second combiner 103b. The second optical system 12b is covered by a second cover member 71b, which is an inner cover. The second image element 11b is disposed so as to cover an opening 71o of the second cover member 71b and is fixed to the second optical system 12b via a rectangular frame-shaped second holder 72b. The second image element 11b and the second optical system 12b correspond to a second display driver 102b. The second display device 100b for the left eye has the same structure and function as the first display device 100a for the right eye. That is, the second image element 11b is similar to the first image element 11a, the second optical system 12b is similar to the first optical system 12a, and the second combiner 103b is similar to the first combiner 103a.

[0015] The first display device 100a and the second display device 100b are internally connected and fixed via a fixing member 78. That is, the fixing member 78 supports the pair of frames 61a and 61b incorporated into the pair of display devices 100a and 100b at the center, maintaining the relative positioning of the first display device 100a and the second display device 100b. Specifically, the first frame 61a is connected to one end of a rod-shaped fixing member 78 at its inner end closer to the second frame 61b, and the second frame 61b is connected to the other end of the rod-shaped fixing member 78 at its inner end closer to the first frame 61a. The first frame 61a and the second frame 61b are semicircular metal members formed of, for example, a magnesium alloy. The fixing member 78 is also formed of, for example, a magnesium alloy. By forming the first frame 61a and the second frame 61b from a material with high heat dissipation properties such as a magnesium alloy, the heat dissipation efficiency of the image element 11a and the like can be improved. By forming the fixing member 78 from a material with high heat dissipation properties, such as a magnesium alloy, it is possible to provide the effect of cooling the first frame 61a and the second frame 61b by dissipating heat.

[0016] A rectangular circuit board 91 is disposed above the fixing member 78 and between the left and right display devices 100a and 100b. The circuit board 91 includes a control device 92 that controls the display operations of the first image element 11a and the second image element 11b. The control device 92 outputs drive signals corresponding to display images to the left and right image elements 11a and 11b to control the display operations of the left and right image elements 11a and 11b. The control device 92 includes, for example, an IF circuit, a signal processing circuit, etc., and causes the left and right image elements 11a and 11b to display two-dimensional images in response to image data or image signals received from an external device. Although not shown, the control device 92 includes a main board that controls the operations of the first display device 100a and the second display device 100b. The main board may have, for example, an interface function for communicating with an external device (not shown) and converting signals received from the external device, and an integration function for coordinating the display operations of the first display device 100a and the second display device 100b.

[0017] FIG. 3 shows the optical module 100 constituting the first display device 100a. In FIG. 3, region BR1 is a plan view of the optical module 100, and region BR2 is a side view of the optical module 100. The first optical system 12a is fixed to the upper surface of a plate-shaped first frame 61a by adhesive or the like, and the first combiner 103a is fixed at its upper end to the front half of the periphery of the first frame 61a by adhesive or the like. The first optical system 12a includes a barrel 31 that supports optical elements. The barrel 31 is disposed between the prism mirror 22, which is a first reflective optical element that bends the optical path by reflection, and the first combiner 103a, which is a second reflective optical element that reflects the image light from the prism mirror 22 toward the pupil position, and serves as a support member for positioning the prism mirror 22. The first combiner 103a is a second reflective optical element that reflects the image light from the prism mirror 22 toward the pupil position. The barrel 31 is a frame-shaped member having a rectangular opening in a plan view, and supports the prism mirror 22 at its upper part, and is fixed at its lower part to the first frame 61a via a wedge-shaped optical element 28. The prism mirror 22 supports the projection lens 21 at its rear, i.e., -Z side, and the projection lens 21 supports the first image element 11a at its end opposite the prism mirror 22 via a first holder 72a.

[0018] FIG. 4 is a side cross-sectional view illustrating the optical structure of the first display device 100a. The first display device 100a includes a first image element 11a and an imaging optical system 20. The imaging optical system 20 includes a projection lens 21, a prism mirror 22, a wedge-shaped optical element 28, and a see-through mirror 23. Of the imaging optical system 20, the projection lens 21, the prism mirror 22, and the wedge-shaped optical element 28 correspond to the first optical system 12a shown in FIG. 3 and other figures, and the see-through mirror 23 corresponds to the first combiner 103a. The first image element 11a, the projection lens 21, the prism mirror 22, and the wedge-shaped optical element 28 are fixed to the first frame 61a in a mutually aligned state, and the main body of the first image element 11a, the projection lens 21, and the prism mirror 22 are housed in a space SP1 sandwiched between the first cover member 71a and the first frame 61a. The wedge-shaped optical element 28 is disposed so as to fit into a step formed in the optical opening OA of the first frame 61a, and the periphery of the optical opening OA is kept airtight.

[0019] The first image element 11a is a self-luminous display device. The first image element 11a is, for example, an organic electroluminescence (EL) display, and forms color still or moving images on a two-dimensional display surface 11d. The first image element 11a is arranged along an xy plane that is slightly rotated and tilted around the X axis relative to the XY plane. The first image element 11a is driven by a circuit board 91 to perform a display operation. The first image element 11a is not limited to an EL display, but can be replaced with a micro LED display, or a display device using an inorganic EL, organic LED, laser array, quantum dot luminescent element, or the like. The first image element 11a is not limited to a self-luminous image light generating device, but may also be composed of an LCD or other light modulation element, and form an image by illuminating the light modulation element with a light source such as a backlight. Instead of an LCD, the first image element 11a can also be composed of an LCOS (Liquid Crystal on Silicon, LCoS is a registered trademark), a digital micromirror device, or the like.

[0020] The projection lens 21 includes a first lens 21p and a second lens 21q. The first lens 21p has an incident surface 21a and an exit surface 21b, and the second lens 21q has an incident surface 21c and an exit surface 21d. The projection lens 21 receives the image light ML emitted from the first image element 11a and makes it incident on the prism mirror 22. The projection lens 21 condenses the image light ML emitted from the first image element 11a into a nearly parallel beam. The prism mirror 22 has an incident surface 22a, an internal reflection surface 22b, and an exit surface 22c. The prism mirror 22 outputs the image light ML incident from the front so as to reflect it in a direction inclined with respect to a direction obtained by reversing the incident direction (the direction of the light source as viewed from the prism mirror 22). Wedge-shaped optical element 28 has first surface 28a and second surface 28b, and passes image light ML emitted from prism mirror 22 and directed toward see-through mirror 23. See-through mirror 23 has reflective surface 23a and outer surface 23o. See-through mirror 23 magnifies the intermediate image formed on the light-emitting side of prism mirror 22.

[0021] The imaging optical system 20 is an off-axis optical system OS due to the see-through mirror 23 being a concave mirror, etc. In this embodiment, the projection lens 21, the prism mirror 22, and the see-through mirror 23 are arranged non-axisymmetrically and have non-axisymmetric optical surfaces. The imaging optical system 20 being an off-axis optical system OS means that the optical path as a whole is bent before and after the light beam is incident on multiple reflective or refracting surfaces in the optical elements 21, 22, 28, and 23 that make up the imaging optical system 20. In this imaging optical system 20, i.e., the off-axis optical system OS, the optical axis AX is bent so that it extends along an off-axis plane (a plane parallel to the YZ plane) corresponding to the paper surface. In this imaging optical system 20, the optical axis AX is bent within the off-axis plane parallel to the YZ plane, and the optical elements 21, 22, 28, and 23 are arranged along this off-axis plane. The optical axis AX of the imaging optical system 20 is arranged along an off-axis plane (a plane parallel to the YZ plane), which is a reference plane extending in the vertical direction, and includes optical axis portions AX1, AX2, and AX3 that are inclined relative to each other before and after the reflecting surface. The optical axis AX as a whole extends along the optical path of the chief ray emitted from the center of the first image element 11a and passes through the eye ring ER, which corresponds to the eyepoint, or the center of the pupil. When viewed in a cross section parallel to the YZ plane, the optical axis AX is arranged in a Z-shape by the multiple optical axis portions AX1, AX2, and AX3. In other words, on the off-axis plane parallel to the YZ plane, an optical path P1 from the projection lens 21 to the internal reflecting surface 22b, an optical path P2 from the internal reflecting surface 22b to the see-through mirror 23, and an optical path P3 from the see-through mirror 23 to the pupil position PP are arranged in two stages in a Z-shape. The imaging optical system 20 is arranged vertically. The off-axis plane (a plane parallel to the YZ plane) that is the reference plane extends parallel to the vertical Y direction. In this case, the optical elements 21, 22, 28, and 23 that make up the first display device 100a are arranged with their height positions changed in the vertical direction, which prevents the width of the first display device 100a from increasing.

[0022] In the imaging optical system 20, an optical path P1 from the projection lens 21 to the internal reflective surface 22b extends obliquely upward toward the rear. That is, in the optical path P1, the optical axis portion AX1 extends in a direction close to halfway between the -Z direction and the +Y direction. An optical path P2 from the internal reflective surface 22b to the see-through mirror 23 extends obliquely downward toward the front. That is, in the optical path P2, the optical axis portion AX2 extends in a direction close to halfway between the +Z direction and the -Y direction. However, when the water surface direction (XZ plane) is used as a reference, the inclination of the optical path P2 is greater than the inclination of the optical path P1. An optical path P3 from the see-through mirror 23 to the pupil position PP is nearly parallel to the Z direction, but in the illustrated example, the optical axis portion AX3 is at an angle of about -10° toward the +Z direction, with downward being negative. In other words, the exit optical axis EX, which is an extension of the optical axis portion AX3, extends at a downward tilt of approximately 10° with respect to the central axis HX, which is parallel to the forward +Z direction. This is because the human gaze is stable with eyes slightly downcast, tilted approximately 10° below the horizontal. Note that the central axis HX, which extends horizontally with respect to the pupil position PP, is designed to assume that the wearer US wearing the first display device 100a is in an upright, relaxed position, facing forward, and gazing horizontally or at the horizon. Although the head shapes and postures of individual wearers US wearing the first display device 100a, including the positions of the eyes and ears, vary, an average central axis HX can be set for the first display device 100a of interest by assuming an average head shape or head posture of the wearers US.

[0023] The incident surface 21a and the exit surface 21b of the first lens 21p constituting the projection lens 21 are asymmetrical about the optical axis AX in the vertical direction parallel to the YZ plane and intersecting the optical axis AX, and are symmetrical about the optical axis AX in the horizontal direction or X direction. The incident surface 21c and the exit surface 21d of the second lens 21q constituting the projection lens 21 are asymmetrical about the optical axis AX in the vertical direction parallel to the YZ plane and intersecting the optical axis AX, and are symmetrical about the optical axis AX in the horizontal direction or X direction. The first lens 21p and the second lens 21q are formed of, for example, resin, but can also be made of glass. The incident surface 21a and the exit surface 21b of the first lens 21p are, for example, free-form surfaces. The incident surface 21a and the exit surface 21b are not limited to free-form surfaces and can also be aspherical surfaces. The incident surface 21c and the exit surface 21d of the second lens 21q are, for example, free-form surfaces. The entrance surface 21c and the exit surface 21d are not limited to free-form surfaces, but may also be aspherical. By making the entrance surfaces 21a, 21c or the exit surfaces 21b, 21d free-form or aspherical, aberrations can be reduced. In particular, when a free-form surface is used, it becomes easy to improve the optical performance of the decentered system, making it easy to reduce aberrations in the imaging optical system 20, which is a non-coaxial off-axis optical system OS. Although detailed illustration is omitted, anti-reflection coatings are formed on the entrance surfaces 21a, 21c and the exit surfaces 21b, 21d.

[0024] The prism mirror 22 is a refractive / reflective optical element that combines the functions of a mirror and a lens. It refracts and reflects the image light ML from the projection lens 21. The prism mirror 22 is a first reflective optical element. The image light ML enters the interior through the incident surface 22a, is totally reflected by the internal reflection surface 22b in a non-frontal direction, and is then emitted to the exterior through the exit surface 22c. The incident surface 22a and the exit surface 22c are curved optical surfaces, contributing to improved resolution compared to a reflective surface alone or a flat surface. The optical surfaces that make up the prism mirror 22—the incident surface 22a, the internal reflection surface 22b, and the exit surface 22c—are asymmetric about the optical axis AX in the vertical direction, which is parallel to the YZ plane and intersects the optical axis AX, and symmetric about the optical axis AX in the horizontal direction or X direction. The prism mirror 22 is formed, for example, from resin, but can also be made of glass. The refractive index of the body of the prism mirror 22 is set to a value that achieves total internal reflection, taking into account the reflection angle of the image light ML. The optical surfaces of the prism mirror 22, i.e., the incident surface 22a, the internal reflection surface 22b, and the exit surface 22c, are, for example, free-form surfaces. The incident surface 22a, the internal reflection surface 22b, and the exit surface 22c are not limited to free-form surfaces, but can also be aspherical. By making the optical surfaces 22a, 22b, and 22c of the prism mirror 22 free-form or aspherical, aberrations can be reduced. In particular, using free-form surfaces facilitates improving the optical performance of the decentered system. The internal reflection surface 22b is not limited to a surface that reflects the image light ML by total reflection, but can also be a reflection surface made of a metal film or a dielectric multilayer film. In this case, a reflection film made of a single layer or multilayer film made of a metal such as Al or Ag is formed on the internal reflection surface 22b by vapor deposition or the like, or a sheet-like reflection film made of metal is attached. Although not shown in detail, an anti-reflection film is formed on the incident surface 22a and the exit surface 22c.

[0025] The wedge-shaped optical element 28 is disposed between the prism mirror 22 and the see-through mirror 23 and is optically transparent. The wedge-shaped optical element 28 serves to improve the imaging state. The first surface 28a provided on the entrance side of the wedge-shaped optical element 28 is a flat but free-form surface, and is asymmetric about the optical axis AX in the vertical direction parallel to the YZ plane, and symmetric about the optical axis AX in the X direction perpendicular to the YZ plane, i.e., the horizontal direction. An anti-reflection coating is formed on the first surface 28a. The second surface 28b provided on the exit side of the wedge-shaped optical element 28 is flat and is also formed with an anti-reflection coating. The thickness of the wedge-shaped optical element 28 is increased on the +Z side, which is the front side. This makes it possible to suppress distortion caused by the prism mirror 22, etc. The refractive index of the wedge-shaped optical element 28 is different from that of the prism mirror 22. This makes it possible to adjust the degree of refraction and dispersion between the wedge-shaped optical element 28 and the prism mirror 22, etc., making it easier to achieve achromatism, for example.

[0026] The see-through mirror 23 is a curved, plate-like optical element that functions as a concave surface mirror and reflects the image light ML from the prism mirror 22. That is, the see-through mirror 23 reflects the image light ML from the emission region of the first optical system 12a toward the pupil position PP. The see-through mirror 23 covers the pupil position PP where the eye EY or pupil is located, and has a concave shape toward the pupil position PP and a convex shape toward the outside. The see-through mirror 23 is a concave transmission mirror that covers the entire effective area of ​​the screen within the field of view. The see-through mirror 23 is a collimator with a converging function that converges, to the pupil position PP, the chief rays of the image light ML that are emitted from each point on the display surface 11d and that once spread due to imaging near the emission region of the first optical system 12a. The see-through mirror 23 is a mirror plate having a structure in which a transparent mirror film 23c is formed on the front or back surface of a plate-like body 23b. The see-through mirror 23 and the reflecting surface 23a are asymmetric about the optical axis AX in the vertical direction, which is parallel to the YZ plane and intersects the optical axis AX, and are symmetric about the optical axis AX in the horizontal direction or X direction. The reflecting surface 23a of the see-through mirror 23 is, for example, a free-form surface. The reflecting surface 23a is not limited to a free-form surface, but can also be an aspherical surface. By making the see-through mirror 23 a free-form or aspherical surface, aberrations can be reduced, and in particular, when a free-form surface is used, it becomes easier to reduce aberrations in the imaging optical system 20, which is an off-axis optical system or a non-coaxial optical system.

[0027] The see-through mirror 23 is a transmissive reflective element that transmits a portion of light upon reflection. The reflective surface 23a or mirror film 23c of the see-through mirror 23 is formed of a semi-transparent reflective layer. This allows external light OL to pass through the see-through mirror 23, enabling a see-through view of the external world and allowing a virtual image to be superimposed on the external world image. In this case, if the plate-like body 23b supporting the mirror film 23c is thin (several millimeters or less), the change in magnification of the external world image can be minimized. The reflectivity of the mirror film 23c for the image light ML and the external world light OL is set to 10% to 50% within the expected range of incident angles of the image light ML, in order to ensure the brightness of the image light ML and facilitate the observation of the external world image through see-through. The plate-like body 23b, which is the base material of the see-through mirror 23, is formed of, for example, resin, but can also be made of glass. The plate-like body 23b is formed of the same material as the support plate 83 that supports it from the periphery and has the same thickness as the support plate 83. The mirror film 23c is formed of, for example, a dielectric multilayer film consisting of multiple dielectric layers with adjusted thicknesses. The mirror film 23c may be a single-layer film or a multilayer film made of a metal such as Al or Ag with adjusted thicknesses. The mirror film 23c can be formed by laminating layers, but can also be formed by attaching a sheet-like reflective film. An anti-reflection film is formed on the outer surface 23o of the plate-shaped body 23b.

[0028] Regarding the optical path, the image light ML from the first image element 11a enters the projection lens 21 and is emitted from the projection lens 21 in a substantially collimated state. The image light ML that passes through the projection lens 21 enters the prism mirror 22, passes through the entrance surface 22a while being refracted, is reflected by the internal reflection surface 22b at a high reflectance close to 100%, and is refracted again by the exit surface 22c. The image light ML from the prism mirror 22 enters the see-through mirror 23 via the wedge-shaped optical element 28, and is reflected by the reflection surface 23a at a reflectance of approximately 50% or less. The image light ML reflected by the see-through mirror 23 enters the pupil position PP, where the eye EY or pupil of the wearer US is located. External light OL that has passed through the see-through mirror 23 and the support plate 83 surrounding it also enters the pupil position PP. That is, the wearer US wearing the first display device 100a can observe a virtual image formed by the image light ML superimposed on an image of the outside world.

[0029] As shown in FIG. 5, the display image formed on the display surface 11d of the first image element 11a is a corrected image DA1 that is pre-imposed with distortions such as trapezoidal distortion. Because the imaging optical system 20 is an off-axis optical system OS, it is not easy to completely eliminate distortions such as trapezoidal distortion using the optical system itself. Therefore, by providing the image displayed on the first image element 11a with distortions that offset the distortions created by the projection lens 21, prism mirror 22, wedge-shaped optical element 28, and see-through mirror 23, the pixel arrangement of the virtual projected image IG1 observed at pupil position PP through the imaging optical system 20 can be a grid pattern corresponding to the original display image DA0, resulting in a rectangular outline. In other words, the first image element 11a corrects the distortions created by the projection lens 21, prism mirror 22, wedge-shaped optical element 28, and see-through mirror 23. As a result, aberrations can be suppressed overall, including the first image element 11a, while allowing for distortions created by the see-through mirror 23 and other components. This increases the degree of freedom in the arrangement and size of optical elements such as the prism mirror 22, making it possible to easily ensure the optical performance of the first display device 100a while achieving a reduction in size of the first display device 100a.

[0030] 6, the relative positions of the projection lens 21, prism mirror 22, and wedge-shaped optical element 28 that constitute the first optical system 12a will be described. As shown in the figure, the distance d12 from the see-through mirror 23 to the wedge-shaped optical element 28 for the lower angle of view light MLa, indicated by the dashed line, is longer than the distance d11 from the see-through mirror 23 to the wedge-shaped optical element 28. This results in decentering aberration. Similarly, in the prism mirror 22, the distance d22 from the internal reflecting surface 22b of the prism to the incident surface 22a for the upper angle of view light MLb is longer than the distance d21 from the internal reflecting surface 22b of the prism to the incident surface 22a for the lower angle of view light MLa, which results in decentering aberration. In this case, decentering aberrations caused by the wedge-shaped optical element 28 and the like can be suppressed by making the optical path lengths of the lower angle of view light MLa and the upper angle of view light MLb as equal as possible. By tilting the optical axis portion AX1 in the direction of the arrow DR and reducing the angle between the optical axis portion AX1 and the optical axis portion AX2, decentering aberrations can be suppressed. In this way, reducing the angle between the optical axis portion AX1 and the optical axis portion AX2 on the internal reflecting surface 22b also has the effect of reducing the amount of forward protrusion of the entire optical system. However, tilting the optical axis portion AX1 on the incident side of the prism mirror 22 in the direction of the arrow DR brings the lower end of the first image element 11a closer to the see-through mirror 23. When the inclination of optical axis portion AX1 is large in this way, if wedge-shaped optical element 28 were positioned near output surface 22c of prism mirror 22 as shown by the dotted line, the lower end of first image element 11a would be positioned below and beyond extension line EL of second surface 28b of wedge-shaped optical element 28, and parts related to the structure or exterior that holds wedge-shaped optical element 28 would have to avoid first image element 11a, complicating the structure of the parts and, further, causing discomfort to the wearer US because the parts would be within the see-through field of view of the wearer US. Therefore, by lowering wedge-shaped optical element 28 to the position shown by the solid line, the lower end of first image element 11a is prevented from being positioned below and beyond the extension line of second surface 28b of wedge-shaped optical element 28.As a result, the wedge-shaped optical element 28 is spaced a predetermined distance from the prism mirror 22, and the distance between the prism mirror (first reflective optical element) 22 and the projection lens (front optical element) 21 in the optical axis direction is shorter than the distance between the prism mirror (first reflective optical element) 22 and the wedge-shaped optical element (rear optical element) 28 in the optical axis direction. In this case, even if the angular difference between the incident optical axis and the exit optical axis of the prism mirror 22 (i.e., the angle between the optical axis portion AX1 and the optical axis portion AX2) is reduced, the first image element 11a is less likely to interfere with the rear optical element in terms of position, reducing geometric constraints on the first frame 61a and the like, allowing for a simplified shape. However, if the wedge-shaped optical element 28 is placed closer to the see-through mirror 23, the see-through viewing angle will be narrowed. In the configuration of this embodiment, the position of the wedge-shaped optical element 28 is lowered while ensuring a see-through viewing angle of approximately 15° to 20° upward. This makes it possible to suppress decentering aberrations and the amount of projection of the optical system toward the front, simplifies the structure of the parts that hold the wedge-shaped optical element 28, reduces discomfort for the wearer US, and ensures the necessary see-through field of view.

[0031] However, if the wedge-shaped optical element 28 is lowered to increase the distance between the wedge-shaped optical element 28 and the prism mirror 22, it becomes difficult to directly cement the wedge-shaped optical element 28 and the prism mirror 22, and it also becomes difficult to ensure accurate positioning. In particular, the prism mirror 22, which has the internal reflective surface 22b, must be positioned with high precision relative to the wedge-shaped optical element 28 and the projection lens 21; otherwise, misalignment may result in degradation of optical performance. In particular, improving the positioning accuracy of the prism mirror 22 and the wedge-shaped optical element 28 in the direction along the YX plane, which is the decentering direction, is important from the perspective of ensuring the optical performance of the entire first optical system 12a, which is composed of the projection lens 21, the prism mirror 22, and the wedge-shaped optical element 28. Furthermore, the first optical system 12a must be strong enough to withstand assembly and impacts such as being dropped. Therefore, the wedge-shaped optical element 28 and the prism mirror 22 are assembled via a barrel 31, as shown in FIG. 3 .

[0032] The barrel 31 shown in FIG. 3 is connected to the see-through mirror 23 or the first combiner 103a via the first frame 61a. The barrel 31 is disposed between the prism mirror 22, which is a first reflecting optical member, and the first combiner 103a, which is a second reflecting optical member, and functions as a support member that positions the prism mirror (first reflecting optical member) 22 with respect to the first combiner (second reflecting optical member) 103a. The projection lens 21, which serves as a front optical member, is disposed on the first image element 11a side of the prism mirror 22, and the projection lens (front optical member) 21 is fixed in a state where it is positioned relative to the prism mirror 22. As described above, due to the small angle formed between the optical axis portion AX1 and the optical axis portion AX2 on the reflecting surface 22b of the prism mirror 22, the barrel (support member) 31 has an opening OP on the incident surface 22a side of the prism mirror 22. In other words, the opening OP increases the degree of freedom in placement, reducing the angular difference between the optical axis portion (incident optical axis) AX1 and the optical axis portion (exit optical axis) AX2 of the first optical axis reflecting optical member. This allows the projection lens (front optical member) 21 to be positioned closer to the exit surface 22c of the prism mirror 22 and the wedge-shaped optical element (rear optical member) 28. As a result, geometric constraints on parts related to the structure or exterior are reduced, allowing for a simpler shape. Meanwhile, a wedge-shaped optical element 28 is positioned as a rear optical member on the first combiner 103a side of the prism mirror 22, and the wedge-shaped optical element (rear optical member) 28 is fixed in a positioned state to the prism mirror 22. The first combiner (second reflecting optical member) 103a is fixed in a positioned state to the first frame 61a, which is a frame member. The first frame (frame member) 61a supports the barrel (support member) 31 via the wedge-shaped optical element 28.

[0033] 3 and 4, the flange portion around the inner reflecting surface 22b is used to position and fix the prism mirror 22 because the optical path is folded back at the inner reflecting surface 22b and the position of the inner reflecting surface 22b has the greatest effect on accuracy compared to the other refracting surfaces 22a and 22c. When positioning and fixing the prism mirror 22, it is necessary to reduce rotational deviation and positional deviation, and in particular, because the prism mirror 22 has a reflective surface, it is desirable to reduce rotational deviation about all axes, and because the prism mirror 22 constitutes an off-axis optical system OS, it is necessary to prioritize reducing positional deviation in the specific direction in which the axis is off.

[0034] First, we will explain rotational misalignment of the prism mirror 22. Consider two intersecting directions within the YZ plane along a first imaginary plane VP1, which includes the optical axis AX of the image light ML incident on the entrance surface 22a of the prism mirror 22 and the optical axis AX of the image light ML exiting from the exit surface 22c, and the X direction, which corresponds to the normal direction to the first imaginary plane VP1. Adjusting the rotational orientation with respect to the two intersecting directions within the YZ plane (e.g., the Y and Z directions) and the X direction—that is, positioning with respect to the angle with respect to the X direction and the angle with respect to the two intersecting directions within the YZ plane—is extremely important because it significantly affects resolution performance and distortion. Specifically, if rotational misalignment of the prism mirror 22 occurs around an axis parallel to the X direction and the positioning accuracy with respect to the angle around the X axis deteriorates, for example, focusing on the chief ray of light at the central angle of view, the angle of incidence on the internal reflecting surface 22b changes, resulting in optical axis misalignment. Furthermore, this affects not only the light at the central angle of view but also light at other angles of view, resulting in a decrease in resolution performance and distortion in the entire optical system. The above has described the case where the positioning accuracy regarding the angle around the X axis has deteriorated, but the same applies when the positioning accuracy regarding the angle around the Y axis or Z axis has deteriorated, and it is necessary to improve the positioning accuracy of the prism mirror 22 regarding rotation in the three axial directions.

[0035] The following describes positional deviation of the prism mirror 22. Comparing the two intersecting directions in the YZ plane along the first imaginary plane VP1, which includes the optical axis AX of the image light ML, before and after incidence on the prism mirror 22, with the X direction, which corresponds to the normal direction to the first imaginary plane VP1, it is clear that the two intersecting directions in the YZ plane require higher positioning accuracy in relation to the optical characteristics of the prism mirror 22. Specifically, the imaging optical system 20, including the prism mirror 22, is an off-axis optical system OS, which decenters and tilts optical components in the YZ direction or uses free-form surfaces. Therefore, if the prism mirror 22 is misaligned in a direction parallel to the YZ plane, for example, focusing on the chief ray of the central angle of view, the incident position on the internal reflecting surface 22b changes in the YZ plane, resulting in not only a positional deviation in the YZ plane but also a relatively large angular change corresponding to the positional deviation. Therefore, it is necessary to improve the positioning accuracy of the prism mirror 22 in the two intersecting directions in the YZ plane. On the other hand, since the imaging optical system 20 including the prism mirror 22 is an axisymmetric system with respect to the X direction, the required accuracy for positioning the prism mirror 22 in the X direction is relatively lower than in the two intersecting directions in the YZ plane.

[0036] 7 and 8, the fixing of the prism mirror 22 and the like to the barrel 31 will be described. In FIG. 7, region CR1 is a side view of the optical block 30 integrated by the barrel 31, region CR2 is a plan view of the optical block 30, region CR3 is a side view of the barrel 31, region CR4 is a plan view of the barrel 31, and region CR5 is a front view of the barrel 31. In FIG. 8, regions DR1 and DR2 are perspective views of the barrel 31, and regions DR3, DR4, and DR5 are perspective views of the prism mirror 22 and the wedge-shaped optical element 28. The prism mirror 22 is fixed in a state where it is positioned relative to the barrel 31 using fitting and offset.

[0037] The upper end 31a of the barrel 31 has a first limiting surface 51a and a second limiting surface 51b that face a pair of side surfaces 22g that extend parallel to each other and are formed on the flange portion 22f of the prism mirror 22 in a first direction x1 (i.e., the X direction) that is parallel to the normal to the first imaginary plane VP1. The first limiting surface 51a and the second limiting surface 51b extend parallel to the YZ plane. The side surface 22g of the prism mirror 22 is positioned in the first direction x1 by being sandwiched between the first limiting surface 51a and the second limiting surface 51b of the barrel 31. As described above, the prism mirror 22 is positioned relative to the barrel 31 in the first direction x1.

[0038] The upper end 31a of the barrel 31 has a pair of first positioning surfaces 52a, 52b that contact a pair of reference surfaces 22h, 22i formed on the flange portion 22f of the prism mirror 22 in a second direction y1 that is perpendicular to the first imaginary plane VP1 and parallel to the normal of a second imaginary plane VP2 onto which the image light ML exiting the exit surface 22c of the prism mirror 22 is incident. The upper end 31a of the barrel 31 also has a second positioning surface 52c that contacts a reference surface 22j formed on the flange portion 22f of the prism mirror 22 in a third direction z1 that is perpendicular to the first direction x1 and intersects with the second direction y1. As described above, the prism mirror 22 is positioned with high precision relative to the barrel 31 in the second direction y1 and the third direction z1. The first direction x1, the second direction y1, and the third direction z1 form local coordinates for positioning the prism mirror 22. The second direction y1 and the third direction z1 are perpendicular to the first direction x1, but the second direction y1 and the third direction z1 are not necessarily perpendicular to each other.

[0039] In the above, the pair of first positioning surfaces 52a, 52b are a pair of band-shaped flat surfaces that are spaced apart in the first direction x1 across the optical axis AX of the image light ML and extend in a direction perpendicular to the first direction x1 and the second direction y1. Since the pair of first positioning surfaces 52a, 52b extend in a direction perpendicular to the first direction x1 and the second direction y1, rotation of the prism mirror 22 around an axis α1 parallel to the first direction x1 can be restricted. Furthermore, since the pair of first positioning surfaces 52a, 52b are spaced apart in the first direction x1 across the optical axis AX, rotation of the prism mirror 22 around an axis β1 perpendicular to the first direction x1 and the second direction y1 can be restricted. Furthermore, the second positioning surface 52c is a band-shaped flat surface that extends in the first direction x1. As a result, the second positioning surface 52c can restrict rotation of the prism mirror 22 around an axis γ1 perpendicular to the first direction x1 and the third direction z1. As a result, the rotational posture of the prism mirror 22 can be set appropriately with respect to the three intersecting axes α1, β1, and γ1.

[0040] The prism mirror 22 is positioned relative to the upper end 31a of the barrel 31 by utilizing (1) the fit between the first limiting surface 51a and the second limiting surface 51b, and (2) the bias relative to the first positioning surfaces 52a, 52b and the second positioning surface 52c, and is fixed to the barrel 31 using a photocurable adhesive, ultrasonic fusion, or the like while maintaining this positioning state.

[0041] The wedge-shaped optical element 28 is fixed in a state where it is positioned relative to the barrel 31 using fitting. A flange portion 28f of the wedge-shaped optical element 28 fits into a lower end portion 31b of the barrel 31. At this time, a stepped side surface 28g of the flange portion 28f faces a lateral limiting surface 53a formed along the inner periphery of the four sides of the barrel 31, and a stepped upper surface 28h of the flange portion 28f faces a lower limiting surface 53b formed along the lower ends of the four sides of the barrel 31. Although a detailed description will be omitted, the stepped fitting structure formed between the lower end portion 31b of the barrel 31 and the wedge-shaped optical element 28 positions the wedge-shaped optical element 28 in the X, Y, and Z directions and with respect to rotation about the X, Y, and Z axes.

[0042] The above describes the structure for positioning and fixing the prism mirror 22 and the wedge-shaped optical element 28 that constitute the first optical system 12a, but the structure for positioning and fixing the optical elements that constitute the second optical system 12b is similar to the structure for positioning and fixing the optical elements that constitute the first optical system 12a.

[0043] Although detailed explanation will be omitted, the structure for positioning and fixing the wedge-shaped optical element 28 relative to the first frame 61a is similar to the structure for positioning and fixing the wedge-shaped optical element 28 relative to the barrel 31, and a step-type fitting structure is used.

[0044] The fixing of the projection lens 21 to the prism mirror 22 will be described with reference to Fig. 9. In Fig. 9, area ER1 is a front view of the optical block 30, area ER2 is a side view of the optical block 30, area ER3 is a perspective view of the optical block 30, and area ER4 is a perspective view of the projection lens 21. The projection lens 21 is fixed in a state where it is positioned relative to the prism mirror 22 of the optical block 30 using fitting and offset.

[0045] The prism mirror 22 has a third limiting surface 54a and a fourth limiting surface 54b that face a pair of parallel-extending inner surfaces 21g formed on a flange portion 21f of a second lens 21q in the subsequent stage of the projection lens 21 in a first direction x2 (i.e., the X direction) parallel to the normal to the first imaginary plane VP1. The third limiting surface 54a and the fourth limiting surface 54b extend parallel to the YZ plane. A pair of claws 21y formed on the flange portion 21f of the second lens 21q are positioned so that their inner surfaces 21g sandwich the third limiting surface 54a and the fourth limiting surface 54b of the prism mirror 22, thereby enabling positioning in the first direction x1. As described above, the projection lens 21 is positioned in the first direction x1 with respect to the prism mirror 22, i.e., the optical block 30.

[0046] The prism mirror 22 has a pair of third positioning surfaces 55a, 55b that contact a pair of reference surfaces 21h, 21i formed on a pair of claws 21y provided on the second lens 21q in a fourth direction z2 that is perpendicular to the first imaginary plane VP1 and parallel to the normal to a third imaginary plane VP3 on which the image light ML emitted from the exit surface 21d of the projection lens 21 is incident. The prism mirror 22 also has a pair of fourth positioning surfaces 55c, 55d that contact a pair of reference surfaces 21j, 21k formed on a pair of claws 21y provided on the second lens 21q in a fifth direction y2 that is perpendicular to the first direction x2 and intersects with the fourth direction z2. As described above, the projection lens 21 is positioned with high precision relative to the prism mirror 22 in the fourth direction z2 and the fifth direction y2. The first direction x2, the fourth direction z2, and the fifth direction y2 form local coordinates for positioning the projection lens 21. The fourth direction z2 and the fifth direction y2 are perpendicular to the first direction x2, but the fourth direction z2 and the fifth direction y2 are not necessarily perpendicular to each other. Furthermore, the fourth direction z2 may be the same direction as the third direction z1.

[0047] In the above, the pair of third positioning surfaces 55a, 55b are a pair of strip-shaped flat surfaces that are spaced apart in the first direction x2 with the optical axis AX of the image light ML between them and extend in a direction perpendicular to the first direction x2 and the fourth direction z2. Since the pair of third positioning surfaces 55a, 55b extend in a direction perpendicular to the first direction x2 and the fourth direction z2, rotation of the projection lens 21 about the axis α2 parallel to the first direction x2 can be restricted. Furthermore, since the pair of third positioning surfaces 55a, 55b are spaced apart in the first direction x2 with the optical axis AX between them, rotation of the second lens 21q or the projection lens 21 about the axis β2 perpendicular to the first direction x2 and the fourth direction z2 can be restricted. Furthermore, the fourth positioning surfaces 55c, 55d are a pair of flat surfaces that are spaced apart in the first direction x2 with the optical axis AX of the image light ML between them. As a result, the fourth positioning surfaces 55c and 55d can restrict rotation of the second lens 21q or the projection lens 21 around the axis γ2 perpendicular to the first direction x2 and the fifth direction y2. As a result, the rotational posture of the projection lens 21 can be appropriately set with respect to the three intersecting axes α2, β2, and γ2.

[0048] The projection lens 21 is positioned relative to the flange portion 22f of the prism mirror 22 by utilizing (1) the fitting between the third limiting surface 54a and the fourth limiting surface 54b, and (2) the bias relative to the third positioning surfaces 55a, 55b and the fourth positioning surfaces 55c, 55d, and while maintaining this positioning state, the projection lens 21 is fixed to the prism mirror 22 using a photocuring adhesive, ultrasonic fusion, or the like.

[0049] The fixation of the first lens 21p and the second lens 21q in the projection lens 21 will be described with reference to FIG. 10. In FIG. 10, region FR1 is a perspective view showing the first lens 21p and the like removed from the first optical system 12a, region FR2 is a perspective view showing the first lens 21p and the like, and region FR3 is a perspective view showing the first optical system 12a with the first holder 72a removed. The first lens 21p and the second lens 21q are positioned and fixed by fitting. At this time, positioning is performed by multiple claws 21t formed on a flange portion 21n of the first lens 21p gripping a flange portion 21f of the second lens 21q so as to sandwich multiple recesses 21s formed on the second lens 21q. The first holder 72a and the first lens 21p are fixed in a state where they are positioned by fitting. At this time, positioning is performed by a plurality of claws 72t formed on the first holder 72a gripping the flange portion 21f of the second lens 21q so as to sandwich a plurality of recesses 21r formed in the first lens 21p.

[0050] The first lens 21p and the second lens 21q can be joined together using a photo-curing adhesive, ultrasonic fusion, etc. After assembling and integrating the projection lens 21, it can be connected to the prism mirror 22, but the manufacturing procedure is not limited to this.

[0051] 11 and 12, the fixing of the see-through mirror 23 or the first combiner 103a to the first frame 61a will be described. In FIG. 11, area GR1 is a side view showing a part of the first display device 100a, and area GR2 is an exploded side view showing a part of the first display device 100a. The first combiner 103a is fixed to the plate-shaped first frame 61a that supports the optical block 30 in a state where it is positioned using fitting and offset.

[0052] The first frame 61a has, at its outer periphery 62, fifth and sixth limiting surfaces 57a and 57b that are slightly inclined symmetrically in opposite directions within the XZ plane with respect to a first direction x3 (i.e., the X direction) that is parallel to the normal to the first imaginary plane VP1. The upper end 83a of the first combiner 103a is positioned with its inner surface 83g sandwiched between the fifth and sixth limiting surfaces 57a and 57b of the first frame 61a, thereby positioning the first combiner 103a with respect to the first direction x3. As described above, the first combiner 103a is positioned with respect to the first frame 61a with respect to the first direction x3.

[0053] The first frame 61a has a pair of protrusions 63 on the lower surface sides of the left and right ends, and the pair of protrusions 63 has a pair of fifth positioning surfaces 58a, 58b that contact a pair of reference surfaces 83h, 83i formed on the rear end of a rib 83d provided on the inside of the upper end 83a of the first combiner 103a in a sixth direction z3 that is perpendicular to the first imaginary plane VP1 and parallel to the normal to a fourth imaginary plane VP4 on which the image light ML emitted from the reflecting surface 23a of the first combiner 103a is incident. In addition, the outer periphery 62 of the first frame 61a has a pair of sixth positioning surfaces 58c, 58d that contact a pair of reference surfaces 83j, 83k formed on the rib 83d of the first combiner 103a in a seventh direction y3 that is perpendicular to the first direction x3 and intersects the sixth direction z3. As a result, the first combiner 103a is positioned with high precision in the sixth direction z3 and the seventh direction y3 relative to the first frame 61a. Note that the first direction x3, the sixth direction z3, and the seventh direction y3 are local coordinates related to the positioning of the first combiner 103a. The sixth direction z3 and the seventh direction y3 are perpendicular to the first direction x3, but the sixth direction z3 and the seventh direction y3 are not necessarily perpendicular. Furthermore, the sixth direction z3 may be the same direction as the third direction z1 and the fourth direction z2. The seventh direction y3 may be the same direction as the fifth direction y2.

[0054] In the above, the pair of fifth positioning surfaces 58a, 58b are a pair of flat surfaces spaced apart in the first direction x3 with the optical axis AX of the image light ML between them. This allows the fifth positioning surfaces 58a, 58b to restrict rotation of the first combiner 103a around the axis γ3 perpendicular to the first direction x3 and the sixth direction z3. The pair of sixth positioning surfaces 58c, 58d are a pair of strip-shaped flat surfaces spaced apart in the first direction x3 with the optical axis AX of the image light ML between them, extending in directions slightly inclined symmetrically in opposite directions within the XZ plane with respect to the sixth direction z3. In this way, the pair of sixth positioning surfaces 58c, 58d extending approximately in the sixth direction z3 allows rotation of the first combiner 103a around the axis α3 parallel to the first direction x3 to be restricted. Furthermore, the fifth positioning surfaces 58a, 58b are spaced apart in the first direction x3 with the optical axis AX of the image light ML between them. This allows the fifth positioning surfaces 58a and 58b to restrict rotation of the first combiner 103a around the axis β3 perpendicular to the first direction x3 and the seventh direction y3. As a result, the rotational orientation of the first combiner 103a can be appropriately set with respect to the three intersecting axes α3, β3, and γ3.

[0055] The first combiner 103a is positioned relative to the outer periphery 62 of the first frame 61a by utilizing (1) the engagement between the fifth limiting surface 57a and the sixth limiting surface 57b, and (2) the bias relative to the fifth positioning surfaces 58a, 58b and the sixth positioning surfaces 58c, 58d, and is fixed to the first frame 61a using a photocurable adhesive, ultrasonic welding, or the like while maintaining this positioning state.

[0056] The above describes the structure for positioning and fixing optical elements such as the prism mirror 22 that constitute the first display device 100a, but the structure for positioning and fixing optical elements that constitute the second display device 100b is similar to the structure for positioning and fixing optical elements that constitute the first display device 100a.

[0057] 13 is a side cross-sectional view illustrating a modified first display device 100a. In this case, the first combiner 103a has a structure in which support members are integrated, and a support frame 85 connected to a support plate 83 supports the wedge-shaped optical element 28. A support portion 131 corresponding to the barrel 31 can be integrated with the support frame 85 and added. In this case, the wedge-shaped optical element 28 and the prism mirror 22 can be directly positioned and fixed to the first combiner 103a. Alternatively, the support frame 85 and the support portion 131 can be integrated, and the prism mirror 22 and the first combiner 103a can be fixed thereto using the same method as above.

[0058] The optical module 100 or HMD 201 of the above embodiment includes: image elements 11a, 11b; a prism mirror (first reflecting optical member) 22 that receives image light ML emitted from the image elements 11a, 11b through an incident surface 22a, reflects it on an internal reflecting surface 22b, and emits it from an exit surface 22c; combiners (second reflecting optical members) 103a, 103b that reflect the image light ML from the prism mirror 22 toward a pupil position; and a barrel (support member) 31 that is disposed between the prism mirror 22 and the combiners 103a, 103b and positions the prism mirror 22. The prism mirror 22 has an optical axis portion AX1 of the image light ML incident on the incident surface 22a and an optical axis portion AX2 of the image light ML emitted from the exit surface 22c. When viewed from a first direction x1 parallel to the normal to a first virtual plane VP1 including the optical axis portion AX2 of the image light ML, the image light ML is emitted from the exit surface in a direction intersecting the optical axis of the image light ML incident on the entrance surface, and the barrel 31 has a first limiting surface 51a and a second limiting surface 51b facing the prism mirror 22 in the first direction x1, and the barrel 31 has first positioning surfaces 52a, 52b that contact the prism mirror 22 in a second direction y1 that is perpendicular to the first virtual plane VP1 and parallel to the normal to a second virtual plane VP2 on which the image light ML exiting the exit surface of the prism mirror 22 is incident, and a second positioning surface 52c that contacts the prism mirror 22 in a third direction z1 that is perpendicular to the first direction x1 and intersects the second direction y1. In this optical module 100 or HMD 201, the arrangement of the prism mirror 22 is restricted by the first limiting surface and the second limiting surface with respect to the first direction x1, alignment is performed by the first positioning surfaces 52a and 52b with respect to the second direction y1, and alignment is performed by the second positioning surface 52c with respect to the third direction z1, thereby setting a three-dimensional arrangement for the prism mirror 22. This optical module 100 is an off-axis system when viewed from the first direction x1, that is, an off-axis optical system OS, but because it is an off-axis optical system OS, the prism mirror 22 is positioned using the first positioning surfaces 52a and 52b and the second positioning surface 52c in the second direction y1 and the third direction z1, which have a relatively large effect on accuracy, and deterioration of imaging accuracy due to positional deviation of the prism mirror 22 can be minimized.

[0059] [Variations and Others] The present invention has been described above in accordance with the embodiments, but the present invention is not limited to the above embodiments and can be implemented in various forms without departing from the spirit of the invention, and for example, the following modifications are also possible.

[0060] The imaging optical system 20 incorporated in the first display device 100a is not limited to the one shown in the figure and can have various configurations. Specifically, the imaging optical system 20 is described as an off-axis optical system OS having asymmetry in the Y direction or vertical direction, but it can also be an off-axis optical system having asymmetry in the X direction or horizontal direction. The optical elements constituting the imaging optical system 20 shown in FIG. 4 are also merely examples, and modifications such as increasing or decreasing the number of lenses, adding mirrors, or adding light-guiding members are possible.

[0061] A dimming device that adjusts light by limiting the amount of light transmitted through the combiners 103a and 103b can be attached to the exterior side of the combiners 103a and 103b. The dimming device adjusts transmittance electrically, for example. Examples of dimming devices that can be used include a mirror liquid crystal display and an electronic shade. The dimming device may also adjust transmittance according to the illuminance of external light.

[0062] The combiners 103a and 103b can be replaced with light-blocking mirrors, in which case the optical system becomes a non-see-through type that does not assume direct observation of the external image.

[0063] The projection lens 21 is configured to be fitted with the prism mirror 22 in the first direction, but a positioning surface may be provided on the projection lens 21 or the prism mirror 22 to position the projection lens 21 so that it is offset in the first direction.

[0064] In a specific embodiment, the optical module includes an imaging element, a first reflecting optical member that causes imaging light emitted from the imaging element to enter from an incident surface, be reflected by an internal reflection surface, and exit from an exit surface, a second reflecting optical member that reflects the imaging light from the first reflecting optical member toward a pupil position, and a support member that is disposed between the first reflecting optical member and the second reflecting optical member and positions the first reflecting optical member, and the first reflecting optical member is parallel to a normal to a first imaginary plane that includes an optical axis of the imaging light that enters the incident surface and an optical axis of the imaging light that exits from the exit surface. When viewed from a first direction, the image light is emitted from the exit surface in a direction intersecting the optical axis of the image light incident on the entrance surface, and the support member has a first limiting surface and a second limiting surface facing the first reflecting optical member in the first direction, and the support member has a first positioning surface that contacts the first reflecting optical member in a second direction that is perpendicular to the first imaginary plane and parallel to the normal of a second imaginary plane on which the image light exiting from the exit surface of the first reflecting optical member is incident, and a second positioning surface that contacts the first reflecting optical member in a third direction that is perpendicular to the first direction and intersects the second direction.

[0065] In the optical module, the arrangement of the first reflecting optical member is restricted by the first limiting surface and the second limiting surface in the first direction, alignment is performed by the first positioning surface in the second direction, and alignment is performed by the second positioning surface in the third direction, thereby setting a three-dimensional arrangement for the first reflecting optical member. This optical module is an off-axis system when viewed from the first direction, but the first reflecting optical member is positioned using the first positioning surface and the second positioning surface in the second and third directions, which are relatively affected by accuracy due to being an off-axis system, and deterioration of imaging accuracy due to positional deviation of the first reflecting optical member can be minimized.

[0066] In a specific aspect, the first positioning surface has a pair of band-shaped flat surfaces that are spaced apart in the first direction and extend perpendicular to the first and second directions, with the optical axis of the image light between them. In this case, the first positioning surfaces can restrict rotation of the first reflecting optical member about an axis parallel to the first direction. Furthermore, the pair of first positioning surfaces can restrict rotation of the first reflecting optical member about an axis perpendicular to the first and second directions. As a result, the rotational orientation of the first reflecting optical member can be appropriately set.

[0067] In a specific aspect, the second positioning surface has a strip-shaped flat surface extending in the first direction, in which case the second positioning surface can restrict rotation of the first reflecting optical member around an axis perpendicular to the first direction and the third direction.

[0068] In a specific aspect, the lens further includes a rear optical member disposed between the first and second reflecting optical members, and the support member supports the rear optical member on the opposite side of the first reflecting optical member in the second direction. The rear optical member serves to improve the imaging state with respect to distortion aberrations and the like.

[0069] In a specific aspect, the imaging device further includes a front optical member disposed between the imaging element and the first reflecting optical member, wherein the distance between the first reflecting optical member and the front optical member in the optical axis direction is shorter than the distance between the first reflecting optical member and the rear optical member in the optical axis direction. In this case, even if the angular difference between the incident optical axis and the exit optical axis of the first reflecting optical member is reduced, the front optical member is less likely to interfere with the exit surface of the first reflecting optical member or the rear optical member in terms of position, thereby reducing shape constraints on parts related to the structure or exterior and enabling a simplification of the shape.

[0070] In a specific aspect, the first reflecting optical element has a third positioning surface that contacts the front optical element in a fourth direction that is perpendicular to the first imaginary plane and parallel to the normal to a third imaginary plane on which image light exiting the exit surface of the front optical element is incident, and a fourth positioning surface that contacts the front optical element in a fifth direction that is perpendicular to the first direction and intersects with the fourth direction. In this case, the front optical element can form a virtual image with reduced aberration. Furthermore, the front optical element is positioned using the third positioning surface and the fourth positioning surface in the fourth and fifth directions, which have a relatively large effect on accuracy due to the off-axis system, and deterioration of imaging accuracy due to positional misalignment of the front optical element can be minimized.

[0071] In a specific aspect, the third positioning surface has a pair of band-shaped flat surfaces that are spaced apart in the first direction across the optical axis and extend perpendicular to the first and fourth directions. In this case, the third positioning surfaces can restrict rotation of the front optical member around an axis parallel to the first direction. Furthermore, the pair of third positioning surfaces can restrict rotation of the front optical member around an axis perpendicular to the first and fourth directions. As a result, the rotational orientation of the front optical member can be appropriately set.

[0072] In a specific aspect, the fourth positioning surface has a pair of flat surfaces spaced apart in the first direction across the optical axis of the image light. In this case, the fourth positioning surface can restrict rotation of the front optical member around an axis perpendicular to the first direction and the fifth direction. As a result, the rotational orientation of the front optical member can be appropriately set.

[0073] In a specific aspect, the support member is open on the side of the incident surface of the first reflecting optical member, in which case the angle difference between the incident optical axis and the exit optical axis of the first reflecting optical member can be reduced, and the front optical member can be disposed close to the exit surface of the first reflecting optical member.

[0074] In a specific aspect, the optical system further includes a frame member that positions the second reflecting optical member, and the frame member has a fifth positioning surface that contacts the second reflecting optical member in a sixth direction that is perpendicular to the first imaginary plane and parallel to the normal to a fourth imaginary plane on which image light emitted from the emission surface of the second reflecting optical member is incident, and a sixth positioning surface that contacts the second reflecting optical member in a seventh direction that is perpendicular to the first direction and intersects with the sixth direction. In this case, the second reflecting optical member is positioned using the fifth positioning surface and the sixth positioning surface in the sixth and seventh directions, which have a relatively large effect on accuracy due to being an off-axis system, and deterioration of imaging accuracy due to positional deviation of the second reflecting optical member can be minimized.

[0075] In a specific aspect, the fifth positioning surface has a pair of flat surfaces spaced apart in the first direction across the optical axis of the image light, in which case the fifth positioning surface can restrict rotation of the front optical member around an axis perpendicular to the first direction and the sixth direction.

[0076] In a specific aspect, the sixth positioning surface has a plane extending approximately perpendicular to the first and seventh directions and spaced apart in the first direction across the optical axis of the image light, and a plane extending approximately in the first direction. In this case, the sixth positioning surface can restrict rotation of the front optical member around an axis perpendicular to the first and seventh directions and around an axis parallel to the first direction.

[0077] In a specific aspect, the support member is connected to a frame member that positions the second reflecting optical member via the rear optical member.

[0078] A head-mounted display device in a specific embodiment includes the optical module described above and a control device that causes the image element to perform a display operation.

[0079] In a specific aspect, a method for manufacturing an optical module includes an imaging element, a first reflective optical member that causes imaging light emitted from the imaging element to enter from an incident surface, be reflected by an internal reflective surface, and exit from an exit surface, a second reflective optical member that reflects the imaging light from the first reflective optical member toward a pupil position, and a support member that is disposed between the first and second reflective optical members and positions the first reflective optical member, wherein the first reflective optical member is oriented in a direction that intersects with the optical axis of the imaging light that enters the incident surface when viewed from a first direction that is parallel to a normal to a first imaginary plane that includes the optical axis of the imaging light that enters the incident surface and the optical axis of the imaging light that exits from the exit surface. The support member has a first limiting surface and a second limiting surface facing the first reflecting optical member in a first direction, and the support member has a first positioning surface that contacts the first reflecting optical member in a second direction that is perpendicular to the first imaginary plane and parallel to the normal of a second imaginary plane on which the image light that is output from the output surface of the first reflecting optical member is incident, and a second positioning surface that contacts the first reflecting optical member in a third direction that is perpendicular to the first direction and intersects with the second direction, and the first reflecting optical member is positioned by fitting using the first limiting surface and the second limiting surface, and by offsetting using the first positioning surface and the second positioning surface.

[0080] In the above-mentioned method for manufacturing an optical module, the first reflective optical element is positioned by offset using the first positioning surface and the second positioning surface in the second and third directions, which have a relatively large impact on accuracy due to the off-axis system, and therefore deterioration of imaging accuracy due to misalignment of the first reflective optical element can be minimized. [Explanation of symbols]

[0081] 11a, 11b...image element, 11d...display surface, 12a...first optical system, 12b...second optical system, 20...imaging optical system, 21...projection lens, 21h, 21i...reference surface, 21j, 21k...reference surface, 22...prism mirror, 22a...incident surface, 22b...internal reflecting surface, 22c...exiting surface, 22g...side surface (for positioning), 22h, 22i...reference surface, 22j...reference surface, 23...see-through mirror, 23a...reflecting surface, 28...wedge-shaped optical element, 30...optical block, 31...barrel, 51a...first limiting surface, 51b...second limiting surface, 52a, 52b...first positioning surface, 52c...second positioning surface, 53a...lateral limiting surface, 53b...lower limiting surface, 54a...third limiting surface, 54b...fourth limiting surface, 55a, 55b...third positioning surface, 55c, 55d...fourth positioning surface, 57a...fifth limiting surface, 57b...sixth limiting surface, 58a, 58b...fifth positioning surface, 58c, 58d...sixth position Determination surface, 61... support plate, 61a... first frame, 61b... second frame, 78... fixing member, 83h, 83i... reference surface, 83j, 83k... reference surface, 100... optical module, 100a... first display device, 100b... second display device, 102... display drive unit, 103a... first combiner, 103b... second combiner, 200... image display device, AX... optical axis, AX1, AX2, AX3... optical axis portion, ER... eye ring, E Y...eye, ML...image light, OS...off-axis optical system, PP...pupil position, US...wearer, VP1...first virtual plane, VP2...second virtual plane, VP3...third virtual plane, VP4...fourth virtual plane, x1...first direction, x2...first direction, x3...first direction, y1...second direction, y2...fifth direction, y3...seventh direction, z1...third direction, z2...fourth direction, z3...sixth direction, α1,β1,γ1...axis, α2,β2,γ2...axis, α3,β3,γ3...axis

Claims

1. An image element that emits image light; a first reflective optical member having an incident surface on which the image light is incident, an exit surface from which the incident image light exits, and a reflecting surface that reflects the image light from the incident surface toward the exit surface; a second reflecting optical member that reflects the image light from the first reflecting optical member toward a pupil position; a rear optical member disposed between the first reflecting optical member and the second reflecting optical member in an optical path of the image light; a support member disposed between the first reflecting optical member and the second reflecting optical member in an optical path of the image light, the support member having a first limiting surface, a second limiting surface facing the first limiting surface in a first direction, a pair of first positioning surfaces contacting the first reflecting optical member in a second direction intersecting the first direction, and a second positioning surface contacting the first reflecting optical member in a third direction perpendicular to the first direction and intersecting the second direction, The pair of first positioning surfaces are spaced apart from each other in the first direction and have flat surfaces extending in a direction perpendicular to the first direction and the second direction, In the second direction, the support member supports the rear optical member opposite the first reflecting optical member.

2. The optical module according to claim 1 , wherein the second positioning surface has a strip-shaped flat surface extending in the first direction.

3. a front optical member disposed between the imaging element and the first reflecting optical member in an optical path of the imaging light, The optical module according to claim 1 , wherein a distance between the first reflecting optical member and the front optical member is shorter than a distance between the first reflecting optical member and the rear optical member.

4. The optical module described in claim 3, wherein the first reflective optical member has, on each of one side and the other side in the first direction, a third positioning surface that contacts the front optical member and a fourth positioning surface that contacts the front optical member and is different from the third positioning surface.

5. The optical module according to claim 4 , wherein the third positioning surface has a strip-shaped flat surface extending in a direction perpendicular to the first direction.

6. The optical module according to claim 4 , wherein the fourth positioning surface has a flat surface.

7. 7. The optical module according to claim 4, wherein the support member is open on a side opposite the second positioning surface in the third direction.

8. An optical module described in any one of claims 1 to 7, further comprising a frame member having a pair of fifth positioning surfaces in contact with the second reflective optical member, and a sixth positioning surface in contact with the second reflective optical member in the second direction and different from the pair of fifth positioning surfaces.

9. The optical module according to claim 8 , wherein the fifth positioning surface has a plane spaced apart in the first direction.

10. The optical module according to claim 8 , wherein the sixth positioning surface has a plane extending in the first direction.

11. The optical module according to claim 8 , wherein the rear optical member is connected to the frame member.

12. The optical module according to any one of claims 1 to 11, A control device that controls the display operation of the image element.

Images