Optical unit, virtual image display device, and method for measuring optical unit

Abstract

To facilitate correcting an optical component and facilitate ensuring and improving the quality of a virtual image.SOLUTION: An optical unit 100 and a virtual image display device, which is an HMD 301 include a plurality of optical members 10. The plurality of optical members 10 each have measurement reference members 11 to 15 that provide references related to the arrangement in non-contact parts. The directions of the plurality of measurement reference members 11 to 15 of the plurality of optical members 10 are unified.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an optical unit constituting a head-mounted display device or the like, a virtual image display device including the optical unit, and a method for measuring the optical unit. [Background technology]

[0002] With regard to an imaging optical system incorporated in a display device or the like, there is a disclosure of a method in which an optical element constituting the imaging optical system, specifically a lens having a free-form surface, is provided with a cylindrical piece-shaped edge and a horizontal reference surface, and the edge and horizontal reference surface are brought into contact with the object, thereby attaching the lens to a measuring instrument or a lens barrel (Patent Document 1). In this case, the optical elements constituting the imaging optical system, such as lenses and mirrors, each have a positioning part, and each optical element is held in a lens barrel, and the lens barrels are connected directly or indirectly, which is thought to ensure the image quality of the virtual image. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-127865 Summary of the Invention [Problem to be solved by the invention]

[0004] While the above-mentioned methods are effective in reducing the relative positional deviation of the optical components that make up the imaging optical system, it is difficult to accurately grasp the degree of positional deviation of each optical component when actually assembled. As a result, it is difficult to correct the optical unit that combines multiple optical components, and it is not easy to ensure or improve the image quality of the virtual image. [Means for solving the problem]

[0005] An optical unit in one aspect of the present invention is an optical unit for imaging that includes a plurality of optical elements, each of which is fixedly positioned at a connected portion and has a measurement reference element at a non-connected portion that provides a reference for positioning. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 2 is an external perspective view illustrating the wearing state of the HMD of the first embodiment. [Figure 2] FIG. 1 is a perspective view showing the appearance of an HMD and the interior with the exterior member removed. [Figure 3] 1A and 1B show a plan view and a side view of an optical unit. [Figure 4] 1A and 1B show a front view and a side view of an optical unit. [Figure 5] FIG. 2 is a conceptual cross-sectional side view illustrating the optical system inside the HMD. [Figure 6] 10A and 10B are diagrams illustrating a method for fixing a prism mirror and a wedge-shaped optical element. [Figure 7] 10A and 10B are diagrams illustrating the fixing of a projection lens to an optical block main body. [Figure 8] 10A and 10B are diagrams illustrating the fixing of a combiner to an optical block. [Figure 9] FIG. 10 is a conceptual side view illustrating a measurement reference member provided on a plurality of optical members. [Figure 10] FIG. 2 is a partially enlarged perspective view illustrating the shape of a measurement reference member. [Figure 11] FIG. 2 is a conceptual diagram illustrating a measurement system of an optical unit. [Figure 12] FIG. [Figure 13] FIG. 10 is a perspective view illustrating a modified example of the measurement reference member. [Figure 14] 10A and 10B show a front view and a side view of an optical unit according to a second embodiment. [Figure 15] FIG. 10 is a conceptual side view illustrating the arrangement of a measurement reference member, etc. [Figure 16]FIG. 16 is a conceptual side view illustrating a modified example of the optical unit of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0007] [First embodiment] Hereinafter, a first embodiment of an optical unit and a virtual image display device according to the present invention will be described with reference to the drawings.

[0008] FIG. 1 is a diagram illustrating a wearing state of an image display device 300. The image display device 300 is a head-mounted virtual image display device, i.e., a head-mounted display (hereinafter also referred to as HMD) 301, and allows an observer or wearer US wearing the device to recognize an image as a virtual image. In FIG. 1 etc., X, Y, and Z are Cartesian coordinate systems, with the +X direction corresponding to the lateral direction in which the eyes EY of the observer or wearer US wearing the HMD 301 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.

[0009] The image display device 300 includes a main body device 300a arranged to cover the eyes of the wearer US, and a pair of temple-shaped support devices 300b that support the main body device 300a. From a functional perspective, the device main body 300a includes a first display device 100a for the left eye and a second display device 100b for the right eye. The first display device 100a is composed of a first display driver 102a arranged at 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 at the top and a second combiner 103b shaped like a pair of glasses that covers the eyes.

[0010] The structure of main body device 300a of image display device 300 will be described with reference to Fig. 2. In Fig. 2, area AR1 is an external perspective view of main body device 300a, and area AR2 is a perspective view exposing the inside of main body device 300a.

[0011] The pair of display drivers 102a, 102b located on the +Y side, i.e., the upper side, of main device 300a 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.

[0012] The first display device 100a for the left eye includes a first image element 41a, a first optical system 20a, a first frame 61a, and a first combiner 103a. The first optical system 20a and the first combiner 103a are fixed to the first frame 61a, and the first image element 41a is fixed to the first optical system 20a. The second display device 100b for the right eye includes a second image element 41b, a second optical system 20b, a second frame 61b, and a second combiner 103b. The second display device 100b for the right eye has the same structure and function as the first display device 100a for the left eye. In other words, the second image element 41b is similar to the first image element 41a, the second optical system 20b is similar to the first optical system 20a, and the second combiner 103b is similar to the first combiner 103a.

[0013] 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 first display device 100a and the second display device 100b in a relatively positioned state. One of the first frames 61a is a semicircular metal member, and its inner end portion closer to the second frame 61b is connected to one end of a rod-shaped fixing member 78 made of metal. The other of the second frames 61b is a semicircular metal member, and its inner end portion closer to the first frame 61a is connected to the other end of the rod-shaped fixing member 78. The pair of frames 61a and 61b are arranged to cover a pair of openings having similar contours formed in the lower exterior member 107b.

[0014] 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 operation of the first image element 41a and the second image element 41b. The control device 92 outputs drive signals corresponding to the display image to the left and right image elements 41a and 41b, thereby controlling the display operation of the left and right image elements 41a and 41b. The control device 92 can perform correction processing such as distortion on the display image. The control device 92 includes, for example, an IF circuit, a signal processing circuit, etc., and causes the left and right image elements 41a and 41b 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 also includes a main board that has an interface function for communicating with an external device (not shown) and an integration function for coordinating the operation of the first display device 100a and the operation of the second display device 100b.

[0015] 3 and 4 show the optical unit 100 constituting the first display device 100a. In FIG. 3, region BR1 is a plan view of the optical unit 100, and region BR2 is a side view of the optical unit 100. In FIG. 4, region CR1 is a front view of the optical unit 100, and region CR2 is a side view of the optical unit 100. The optical unit 100 is an imaging optical system and includes a first optical system 20a, a first frame 61a, and a first combiner 103a, and is also referred to as an optical module. The first display device 100a is formed by assembling a first image element 41a to the optical unit 100. The optical unit 100 forms a virtual image from the image light incident from the first image element 41a.

[0016] In the optical unit 100, the first optical system 20a 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 20a includes a barrel 31 that supports optical elements. The barrel 31 is a support member disposed between the prism mirror 22 and the first combiner 103a, etc., and supports the prism mirror 22 at its upper part on the +Y side and is fixed to the first frame 61a at its lower part via a wedge-shaped optical element 23. The prism mirror 22 supports the projection lens 21 at its front, i.e., on the +Z side, and the projection lens 21 supports the first image element 41a at its end opposite the prism mirror 22 via a first holder 72a.

[0017] The projection lens 21 includes a first lens 21p and a second lens 21q. The first lens 21p has a first measurement reference member 11, which is a protruding portion, formed on it. The second lens 21q has a second measurement reference member 12, which is a protruding portion, formed on it. The prism mirror 22 has a third measurement reference member 13, which is a protruding portion, formed on it. The wedge-shaped optical element 23 has a fourth measurement reference member 14, which is a protruding portion, formed on it. The see-through mirror 25, which is the first combiner 103a, has a fifth measurement reference member 15, which is a protruding portion, formed on it. The first measurement reference member 11, the second measurement reference member 12, the third measurement reference member 13, the fourth measurement reference member 14, and the fifth measurement reference member 15 are all aligned in the same direction (see arrows in Figures 3 and 4 ) to provide a reference using their shape characteristics or to be positioned relative to one another. The external appearance of each of the first, second, second, third, third, fourth, and fifth measurement reference members 11, 12, 13, 14, and 15 can be observed collectively from above, i.e., the +Y side, and can also be observed collectively from behind, i.e., the -Z side. In other words, these measurement reference members 11-15 can provide relative positional relationships through collective measurement and are used to determine the positional relationships of the projection lens 21, prism mirror 22, wedge-shaped optical element 23, and first combiner 103a. The first lens 21p, the second lens 21q, the prism mirror 22, and the wedge-shaped optical element 23 correspond to the first optical member, the second optical member, the third optical member, and the fourth optical member, respectively. The see-through mirror 25 or the first combiner 103a corresponds to the fifth optical member. These optical members each have a connecting portion. The first optical member and the second optical member are directly fixed at the connecting portion, the second optical member and the third optical member are directly fixed at the connecting portion, the third optical member and the fourth optical member are directly fixed at the connecting portion, and the fourth optical member and the fifth optical member are directly fixed at the connecting portion. The first measurement reference member 11, the second measurement reference member 12, the third measurement reference member 13, the fourth measurement reference member 14, and the fifth measurement reference member 15 are formed in the non-connected portions of the respective optical members other than the connected portions.

[0018] 5 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 41a and an optical unit 100. The optical unit 100 includes, as optical elements, a projection lens 21, a prism mirror 22, a wedge-shaped optical element 23, and a see-through mirror 25. Of the optical unit 100, the projection lens 21, the prism mirror 22, and the wedge-shaped optical element 23 correspond to the first optical system 20a shown in FIG. 2, and the see-through mirror 25 corresponds to the first combiner 103a. In the optical unit 100, the wedge-shaped optical element 23 is disposed so as to fit into a step formed in the optical opening OA of the first frame 61a.

[0019] The first image element 41a is a self-luminous display device. The first image element 41a is, for example, an organic electroluminescence (EL) display, and forms color still or moving images on a two-dimensional display surface 41d. The first image element 41a is not limited to an organic EL display, but can be replaced with a micro LED display, or a display device using an inorganic EL, an organic LED, a laser array, a quantum dot luminescent element, or the like. The first image element 41a is not limited to a self-luminous image light generating device, but may be composed of an LCD or other light modulation element, and may 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 41a can also be composed of 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 41a and makes it incident on the prism mirror 22. The projection lens 21 condenses the image light ML emitted from the first image element 41a 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 turn it back in a direction tilted downward with respect to a direction obtained by reversing the incident direction (the direction of the light source as seen from the prism mirror 22). Wedge-shaped optical element 23 has incident surface 23a and exit surface 23b, and passes image light ML emitted from prism mirror 22 and directed toward see-through mirror 25. See-through mirror 25 has reflective surface 25a and an outer surface 25o. See-through mirror 25 magnifies the intermediate image formed on the light exit side of prism mirror 22.

[0021] The optical unit 100 is an off-axis optical system OS due to the see-through mirror 25 being a concave mirror, among other factors. In this embodiment, the optical elements, specifically the projection lens 21, prism mirror 22, wedge-shaped optical element 23, and see-through mirror 25, are arranged non-axisymmetrically and have non-axisymmetric optical surfaces. In this optical unit 100, 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, and the optical elements 21, 22, 23, and 25 are arranged along this off-axis plane. When viewed in a cross section parallel to the YZ plane, the optical axis AX is arranged in a Z-shape with multiple optical axis portions AX1, AX2, and AX3 that are inclined relative to each other before and after the reflecting surface. That is, on an off-axis plane parallel to the YZ plane, an optical path P1 from the projection lens 21 to the internal reflective surface 22b, an optical path P2 from the internal reflective surface 22b to the see-through mirror 25, and an optical path P3 from the see-through mirror 25 to the pupil position PP are folded back in two stages in a Z shape. The off-axis plane (a plane parallel to the YZ plane) that serves as a reference plane extends parallel to the vertical Y direction. In this case, the optical members 21, 22, 23, and 25 that constitute the first display device 100a are arranged with their height positions changed in the vertical direction.

[0022] 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 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 incident surface 21c and the exit surface 21d are not limited to free-form surfaces, but may be aspherical. Although not shown in detail, anti-reflection coatings are formed on the incident surfaces 21a and 21c and the exit surfaces 21b and 21d.

[0023] The prism mirror 22 is a refractive / reflective optical element that combines the functions of a mirror and a lens, and refracts and reflects the image light ML from the projection lens 21. The prism mirror 22 allows the image light ML to enter through the entrance surface 22a, totally reflects the incident image light ML off-front by the internal reflection surface 22b, and emits the incident image light ML to the outside through the exit surface 22c. The entrance surface 22a, the internal reflection surface 22b, and the exit surface 22c, which are optical surfaces that make up the prism mirror 22, are asymmetric about the optical axis AX in the vertical direction that 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 prism mirror 22 is made of 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 reflection on the internal surface, 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. 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 detailed illustration is omitted, an anti-reflection film is formed on the incident surface 22a and the exit surface 22c.

[0024] The wedge-shaped optical element 23 is disposed between the prism mirror 22 and the see-through mirror 25 and serves to improve the imaging state. The entrance surface 23a and exit surface 23b of the wedge-shaped optical element 23 are 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. The wedge-shaped optical element 23 is formed of resin, but can also be made of glass. The entrance surface 23a and exit surface 23b of the wedge-shaped optical element 23 are, for example, free-form surfaces. The entrance surface 23a and exit surface 23b are not limited to free-form surfaces, and can also be aspherical. Although detailed illustrations are omitted, an anti-reflection coating is formed on the entrance surface 23a and exit surface 23b. The wedge-shaped optical element 23 is thicker on the +Z side, which is the front side. This makes it possible to suppress distortion caused by the prism mirror 22 and the like. The refractive index of the wedge-shaped optical element 23 is different from the refractive index of the prism mirror 22. This makes it possible to adjust the degree of refraction and dispersion between the wedge-shaped optical element 23 and the prism mirror 22, etc., making it easier to achieve achromatism, for example.

[0025] The see-through mirror 25 is a curved, plate-like optical element that functions as a concave mirror and reflects the image light ML from the prism mirror 22. That is, the see-through mirror 25 reflects the image light ML from the first optical system 20a toward the pupil position PP. The see-through mirror 25 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 25 covers the entire effective area of ​​the screen within the field of view. The see-through mirror 25 is a collimator with a converging function, and reflects and converges the chief rays of the image light ML emitted from each point on the display surface 41d, which are temporarily spread by image formation near the emission area of ​​the first optical system 20a, toward the pupil position PP. The see-through mirror 25 is a mirror plate having a structure in which a transparent mirror film 25c is formed on the front or back surface of a plate-shaped body 25b. The see-through mirror 25 and the reflecting surface 25a are asymmetric about the optical axis AX in the vertical direction, which is parallel to the YZ plane and intersects with the optical axis AX, and are symmetric about the optical axis AX in the horizontal direction or X direction. The reflecting surface 25a of the see-through mirror 25 is, for example, a free-form surface. The reflecting surface 25a is not limited to a free-form surface, and can also be an aspherical surface.

[0026] The see-through mirror 25 is a transmissive reflective element that transmits a portion of light upon reflection. The mirror film 25c of the see-through mirror 25 is formed of a semi-transparent reflective layer. This allows external light OL to pass through the see-through mirror 25, 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-shaped body 25b supporting the mirror film 25c is thin (several millimeters or less), the change in magnification of the external world image can be minimized. The reflectance of the mirror film 25c 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-shaped body 25b, which is the base material of the see-through mirror 25, is formed of, for example, resin, but can also be made of glass. The plate-shaped body 25b 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 25c is formed of, for example, a dielectric multilayer film consisting of multiple dielectric layers with adjusted thicknesses. The mirror film 25c 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 25c 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 25o of the plate-shaped body 25b.

[0027] In the above, by making the lenses 21p, 21q, prism mirror 22, wedge-shaped optical element 23, and see-through mirror 25 that constitute the projection lens 21 free-form or aspherical, aberrations can be reduced, and 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 optical unit 100, which is a non-coaxial off-axis optical system OS.

[0028] Regarding the optical path, the image light ML from the first image element 41a 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 at the exit surface 22c. The image light ML from the prism mirror 22 enters the see-through mirror 25 via the wedge-shaped optical element 23, and is reflected by the reflection surface 25a at a reflectance of approximately 50% or less. The image light ML reflected by the see-through mirror 25 enters the pupil position PP, where the eye EY or pupil of the wearer US is located. External light OL that passes through the see-through mirror 25 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] Although not shown, light blocking members are disposed at appropriate positions between adjacent elements among the projection lens 21, the prism mirror 22, the wedge-shaped optical element 23, and the see-through mirror 25.

[0030] The following describes the positioning and fixing of elements such as the prism mirror 22, the wedge-shaped optical element 23, and the projection lens 21 that constitute the first optical system 20a or the optical block OB shown in FIG. 3 and other figures.

[0031] 6 is a diagram illustrating a method for fixing the prism mirror 22 and the wedge-shaped optical element 23 via the barrel 31. In FIG. 6, region DR1 is a side view of the optical block main body 30 integrated by the barrel 31, and region DR2 is a plan view of the optical block main body 30. Note that the optical block OB in which the prism mirror 22 and the wedge-shaped optical element 23 are integrated by the barrel 31 is referred to as the optical block main body 30.

[0032] The prism mirror 22 is fixed to the barrel 31 in a positioned state using fitting and offset. Specifically, the upper surfaces of a pair of fitting portions 31y formed on the upper portion 31a of the barrel 31 and the inner surface of the limiting plate 31z abut against the lower surface of the flange portion 22f of the prism mirror 22, and while the prism mirror 22 is supported on the fitting portions 31y in an inclined state, the stepped side surface 22g of the flange portion 22f is sandwiched between the inner surfaces of the fitting portions 31y. This positions the prism mirror 22 relative to the barrel 31 in terms of its arrangement in three axial directions (X, Y, and Z directions) and its rotational posture about the three axes. A photocurable adhesive, ultrasonic fusion, or the like can be used to bond the prism mirror 22 to the barrel 31.

[0033] A quadrangular prism-shaped third measurement reference member 13 is formed on flange portion 22f of prism mirror 22. Third measurement reference member 13 is provided so as to protrude laterally from flange portion 22f in a side surface region of flange portion 22f, which is a frame FL3 provided on the outside of prism mirror 22, that is exposed as the exterior of optical block OB, which is the internal structure. The location where third measurement reference member 13 is formed is a region of step side surface 22g excluding contact surfaces and connection portions such as recesses 22s, which will be described later, in other words, a non-connection portion PN.

[0034] The wedge-shaped optical element 23 is fixed in a state where it is positioned using fitting relative to the barrel 31. Specifically, the inner surface and lower end surface of fitting portion 31x, which correspond to the four sides of the lower portion 31b of the barrel 31, fit into the stepped side surface 23g and stepped upper surface 23h of the flange portion 23f of the wedge-shaped optical element 23. This positions the wedge-shaped optical element 23 relative to the barrel 31 in terms of the arrangement in the three axial directions and the rotational posture about the three axes. A photo-curing adhesive, ultrasonic fusion, or the like can be used to bond the wedge-shaped optical element 23 and the barrel 31.

[0035] A triangular prism-shaped fourth measurement reference member 14 is formed on the flange portion 23f of the wedge-shaped optical element 23. The fourth measurement reference member 14 is provided so as to protrude laterally from the flange portion 23f in a side surface region that is exposed as the exterior of the optical block OB, of the flange portion 23f, which is a frame FL4 provided on the outside of the wedge-shaped optical element 23. The location where the fourth measurement reference member 14 is formed is a region of the step side surface 23g and the step top surface 23h excluding connection portions such as abutment surfaces, that is, a non-connection portion.

[0036] The fixing of the projection lens 21 to the optical block main body 30 will be described with reference to Fig. 7. In Fig. 7, an area ER1 is a perspective view of the optical block main body 30 before the fixing of the projection lens 21. In Fig. 7, an area ER2 is a perspective view of the optical block main body 30 to which the projection lens 21 is fixed and the projection lens 21.

[0037] The projection lens 21 is fixed directly to the prism mirror 22 of the optical block main body 30. At this time, the projection lens 21 is fixed in a state in which it is positioned relative to the prism mirror 22 by fitting and offsetting. Specifically, a pair of claws 21y (only one of which is shown) formed on a flange portion 21f of a second lens 21q constituting the projection lens 21 is inserted into a pair of recesses 22s formed on the flange portion 22f of the prism mirror 22 so as to sandwich the pair of recesses 22s. As a result, the pair of claws 21y of the second lens 21q grips the flange portion 22f of the prism mirror 22. At this time, the pair of claws 21y fit into the pair of recesses 22s, and offsetting is performed so that reference surfaces provided on both lenses abut against each other. As a result, the second lens 21q, i.e., the projection lens 21, is positioned relative to the prism mirror 22 in terms of the arrangement in the three axial directions and the rotational posture about the three axes. The second lens 21q and the prism mirror 22 can be bonded together using a photo-curing adhesive, ultrasonic fusion, or the like.

[0038] A triangular prism-shaped second measurement reference member 12 is formed on the flange portion 21f of the second lens 21q. The second measurement reference member 12 is provided so as to protrude laterally from the flange portion 21f in a side surface region of the flange portion 21f, which is a frame FL2 provided on the outside of the second lens 21q and is exposed as the exterior of the optical block OB (see FIG. 4). The area where the second measurement reference member 12 is formed is an area excluding connection portions such as the recesses 21s, i.e., a non-connection portion.

[0039] In the projection lens 21, the first lens 21p is directly fixed to the second lens 21q. At this time, the first lens 21p is fixed in a state in which it is positioned relative to the second lens 21q by fitting. Specifically, two sets of claws 21t (only one set is shown) formed on a flange portion 21n of the first lens 21p are inserted into a pair of recesses 21s (only one is shown) formed on a flange portion 21f of the second lens 21q so as to sandwich the pair of recesses 21s. As a result, the multiple claws 21t of the first lens 21p grip the flange portion 21f of the second lens 21q. At this time, the two sets of claws 21t fit into the pair of recesses 21s. As a result, the first lens 21p is positioned relative to the second lens 21q in terms of its arrangement in three axial directions and its rotational posture about three axes. A photocurable adhesive, ultrasonic fusion, or the like can be used to bond the first lens 21p and the second lens 21q.

[0040] A triangular prism-shaped first measurement reference member 11 is formed on flange portion 21n of first lens 21p. First measurement reference member 11 is provided so as to protrude laterally from flange portion 21n in a side surface region of flange portion 21n, which is a frame FL1 provided on the outside of first lens 21p and is exposed as the exterior of optical block OB (see FIG. 4). The area where first measurement reference member 11 is formed is an area excluding connection portions such as recesses 21r, i.e., a non-connection portion.

[0041] The first holder 72a supporting the first image element 41a is directly fixed to the first lens 21p of the projection lens 21 using a pair of recesses 21r formed in the flange portion 21n of the first lens 21p in a manner similar to that used to fix the first lens 21p to the second lens 21q.

[0042] As described above, the prism mirror 22 and projection lens 21 that make up the optical block OB are directly fixed to each other using a structure that positions them relative to each other, without the need for common components such as a lens frame or case. This makes it possible to miniaturize the optical block OB while increasing the assembly precision between the necessary components (specifically, between the prism mirror 22 and the projection lens 21).

[0043] Fixing the see-through mirror 25 or the first combiner 103a to the first frame 61a will be described with reference to Fig. 8. In Fig. 8, area FR1 is a side view showing a part of the first display device 100a, and area FR2 is an exploded side view showing a part of the first display device 100a.

[0044] The see-through mirror 25 is fixed to a plate-shaped first frame 61a that supports the optical block 30, in a state where it is positioned using fitting and offset. Specifically, a pair of protrusions 63 (only one is shown) is formed on the underside of the first frame 61a in the ±X directions, i.e., at the left and right end portions 62. The see-through mirror 25 has a pair of left and right ribs 83d (only one is shown) formed on the inside in the -Z direction along the upper edge 83a. The reference surfaces, which are the front ends of the protrusions 63 formed on the first frame 61a, abut against the reference surfaces, which are the rear ends of the ribs 83d formed on the see-through mirror 25. Furthermore, the reference surfaces, which are the lower and side surfaces of the end portion 62 of the first frame 61a, abut against the reference surfaces, which are the upper surfaces of the ribs 83d of the see-through mirror 25 and the inner surface of the upper edge 83a. As described above, the see-through mirror 25 is positioned relative to the first frame 61a in terms of its arrangement in the three axial directions and its rotational posture about the three axes. A photocurable adhesive, ultrasonic fusion, or the like can be used to join the first frame 61a and the see-through mirror 25. The wedge-shaped optical element 23 of the optical block main body 30 is fixed in a positioned state to the first frame 61a, and as a result, the see-through mirror 25 is fixed in a positioned state relative to the wedge-shaped optical element 23.

[0045] A triangular prism-shaped fifth measurement reference member 15 is formed on the upper edge 83a of the see-through mirror 25. The fifth measurement reference member 15 is provided so as to protrude upward from the upper edge 83a in an area of ​​the upper edge 83a, which is a frame FL5 provided on the outside of the see-through mirror 25, that is exposed as the exterior of the optical unit 100 when removed from the HMD 301. The location where the fifth measurement reference member 15 is formed is an area of ​​the upper edge 83a excluding connection portions such as the inner surface that abuts against the first frame 61a, i.e., a non-connection portion.

[0046] The first measurement reference member 11, the second measurement reference member 12, the third measurement reference member 13, the fourth measurement reference member 14, and the fifth measurement reference member 15 are integrally formed as a single unit so as to be accessible from the outside when the first lens 21p, the second lens 21q, the prism mirror 22, and the see-through mirror 25 are manufactured. In particular, by adjusting their relative positions, not only is the positioning accuracy of the measurement reference members 11 to 15 relative to the main body ensured, but these measurement reference members 11 to 15 can also be observed collectively. Any one of the measurement reference members 11 to 15 can be used as a datum reference for the optical unit 100, but all do not have to be datum references.

[0047] Hereinafter, the specific shapes of the individual measurement reference members 11 to 15 will be described with reference to FIG. 9 and other figures.

[0048] As shown in FIGS. 9 and 10 , the first measurement reference member 11 is a member formed in association with the first lens 21p. The first measurement reference member 11 includes three measurement reference surfaces RS11, RS12, and RS13 as measurement reference shapes, and three measurement reference lines RL11, RL12, and RL13. Here, the measurement reference line RL11 corresponds to the intersection line of the pair of measurement reference surfaces RS11 and RS12, the measurement reference line RL12 corresponds to the intersection line of the pair of measurement reference surfaces RS12 and RS13, and the measurement reference line RL13 corresponds to the intersection line of the pair of measurement reference surfaces RS13 and RS11. The first measurement reference member 11 provides an origin O1 and local coordinates X1, Y1, and Z1 with respect to the arrangement and orientation of the first lens 21p. The local coordinates X1, Y1, and Z1 correspond to the coordinates obtained by rotating the overall Cartesian coordinate system X, Y, and Z around the X axis, and are mutually orthogonal. Measurement is performed on the assumption that the local coordinates X1, Y1, and Z1 are approximately perpendicular to each other in the actual object. In the illustrated example, the local coordinate X1 is on an extension of the measurement reference line RL11, the local coordinate Y1 coincides with the measurement reference line RL12, and the local coordinate Z1 coincides with the measurement reference line RL13.

[0049] 9, the second measurement reference member 12 is a member formed accompanying the second lens 21q. The second measurement reference member 12 includes three measurement reference surfaces RS21, RS22, and RS23 and three measurement reference lines RL21, RL22, and RL23 as a measurement reference shape. Here, the measurement reference line RL21 corresponds to the intersection line of the pair of measurement reference surfaces RS21 and RS22, the measurement reference line RL22 corresponds to the intersection line of the pair of measurement reference surfaces RS22 and RS23, and the measurement reference line RL23 corresponds to the intersection line of the pair of measurement reference surfaces RS23 and RS21. The second measurement reference member 12 provides an origin O2 and local coordinates X2, Y2, and Z2 for the arrangement and attitude of the second lens 21q. The local coordinates X2, Y2, and Z2 correspond to the overall Cartesian coordinate system X, Y, and Z rotated around the X axis, and in design, their orientations are aligned with the local coordinates X1, Y1, and Z1 of the first measurement reference member 11. Measurement is performed on the assumption that the orientations of the local coordinates X2, Y2, and Z2 do not strictly match those of the local coordinates X1, Y1, and Z1 in the actual object. In the illustrated example, the local coordinate X2 is on an extension of the measurement reference line RL21, the local coordinate Y2 coincides with the measurement reference line RL22, and the local coordinate Z2 coincides with the measurement reference line RL23.

[0050] The third measurement reference member 13 is a member formed accompanying the prism mirror 22. The third measurement reference member 13 includes three measurement reference surfaces RS31, RS32, and RS33 as a measurement reference shape, and three measurement reference lines RL31, RL32, and RL33. Here, the measurement reference line RL31 corresponds to the intersection line of the pair of measurement reference surfaces RS31 and RS32, the measurement reference line RL32 corresponds to the intersection line of the pair of measurement reference surfaces RS32 and RS33, and the measurement reference line RL33 corresponds to the intersection line of the pair of measurement reference surfaces RS33 and RS31. The third measurement reference member 13 provides an origin O3 and local coordinates X3, Y3, and Z3 for the arrangement and attitude of the prism mirror 22. The local coordinates X3, Y3, and Z3 correspond to the overall Cartesian coordinate system X, Y, and Z rotated around the X axis, and in design, their orientations are aligned with the local coordinates X1, Y1, and Z1 of the first measurement reference member 11. The local coordinates X3, Y3, and Z3 are measured on the assumption that, strictly speaking, the orientations of the actual object do not match those of the local coordinates X1, Y1, and Z1. In the illustrated example, the local coordinate X3 is on an extension of the measurement reference line RL31, the local coordinate Y3 is on an extension of the measurement reference line RL32, and the local coordinate Z3 is on an extension of the measurement reference line RL33.

[0051] The fourth measurement reference member 14 is a member formed accompanying the wedge-shaped optical element 23. The fourth measurement reference member 14 includes three measurement reference surfaces RS41, RS42, and RS43 as a measurement reference shape, and three measurement reference lines RL41, RL42, and RL43. Here, the measurement reference line RL41 corresponds to the intersection line of the pair of measurement reference surfaces RS41 and RS42, the measurement reference line RL42 corresponds to the intersection line of the pair of measurement reference surfaces RS42 and RS43, and the measurement reference line RL43 corresponds to the intersection line of the pair of measurement reference surfaces RS43 and RS41. The fourth measurement reference member 43 provides an origin O4 and local coordinates X4, Y4, and Z4 regarding the arrangement and attitude of the wedge-shaped optical element 23. The local coordinates X4, Y4, and Z4 correspond to the overall Cartesian coordinate system X, Y, and Z rotated around the X axis, and in design, their orientations are aligned with the local coordinates X1, Y1, and Z1 of the first measurement reference member 11. The local coordinates X4, Y4, and Z4 are measured on the assumption that, strictly speaking, the orientations of the actual object do not match those of the local coordinates X1, Y1, and Z1. In the illustrated example, the local coordinate X4 is on an extension of the measurement reference line RL41, the local coordinate Y4 is on an extension of the measurement reference line RL42, and the local coordinate Z4 is aligned with the measurement reference line RL43.

[0052] The fifth measurement reference member 15 is a member formed accompanying the see-through mirror 25 or the first combiner 103a. The fifth measurement reference member 15 includes three measurement reference surfaces RS51, RS52, and RS53 as a measurement reference shape, and three measurement reference lines RL51, RL52, and RL53. Here, the measurement reference line RL51 corresponds to the intersection line of the pair of measurement reference surfaces RS51 and RS52, the measurement reference line RL52 corresponds to the intersection line of the pair of measurement reference surfaces RS52 and RS53, and the measurement reference line RL53 corresponds to the intersection line of the pair of measurement reference surfaces RS53 and RS51. The fifth measurement reference member 53 provides an origin O5 and local coordinates X5, Y5, and Z5 for the arrangement and orientation of the see-through mirror 25. The local coordinates X5, Y5, and Z5 correspond to the overall Cartesian coordinate system X, Y, and Z rotated around the X axis, and in design, their orientations are aligned with the local coordinates X1, Y1, and Z1 of the first measurement reference member 11. The local coordinates X5, Y5, and Z5 are measured on the assumption that, strictly speaking, the orientations of the actual object do not match those of the local coordinates X1, Y1, and Z1. In the illustrated example, the local coordinate X5 is on an extension of the measurement reference line RL51, the local coordinate Y5 is on an extension of the measurement reference line RL52, and the local coordinate Z5 is aligned with the measurement reference line RL53.

[0053] 11 is a conceptual diagram illustrating a measurement system 1 of an optical unit 100. The optical unit 100 shown in FIG. 3 and other figures includes, as optical elements, a plurality of optical members 10, specifically, lenses 21p, 21q, a prism mirror 22, a wedge-shaped optical element 23, and a see-through mirror 25 (see FIG. 5). The measurement system 1 uses two measurement methods to evaluate the shape accuracy, including the optical accuracy, of each optical member 10, and also evaluates the optical accuracy of an optical unit 100 assembled from a plurality of optical members 10. The measurement system 1 includes a first measurement device 2, a second measurement device 3, and an information processing device 4.

[0054] The first measurement device 2 is, for example, a known three-dimensional shape measurement device and includes a measurement head 2a, a stage 2b, and a drive control device 2c. When the first measurement device 2 is a three-dimensional shape measurement device, the measurement head 2a enables contact-type shape measurement using, for example, a probe that displaces three-dimensionally. The stage 2b supports the optical element 10 via a holder 2h, allowing the optical element 10 to be positioned and oriented as desired. The drive control device 2c operates the measurement head 2a and stage 2b to detect the surface shape of the optical element 10 with high accuracy. The drive control device 2c temporarily stores the measurement results of the surface shape of the optical element 10 and outputs the surface measurement data to the information processing device 4. The first measurement device 2 can measure the surfaces and lines that constitute a characteristic shape formed within or outside the optical surface of the optical element 10, thereby determining the position and orientation of the characteristic shape. When the optical element 10 has a plurality of optical surfaces and the first measuring device 2 cannot measure the plurality of optical surfaces simultaneously, the first measuring device 2 remeasures the optical element 10 after rearranging the setting by inverting the optical element 10 relative to the holder 2h.

[0055] The second measurement device 3 is, for example, a known tool microscope and includes a measurement head 3a, a stage 3b, and a drive control device 3c. When the second measurement device 3 is a tool microscope, the measurement head 3a enables non-contact dimensional measurement using, for example, an imaging optical system or an image sensor. The stage 3b supports the optical unit 100 and the optical member 10 via a holder 3h, enabling the desired position and orientation of the optical unit 100 and the optical member 10 to be set. The drive control device 3c operates the measurement head 3a and the stage 3b and measures shape information such as the position and dimensions of each part of the optical unit 100 and the optical member 10 with high accuracy through image processing of the obtained image data. The drive control device 3c temporarily stores the shape information of the optical unit 100 and the optical member 10 and outputs the shape measurement data to the information processing device 4. The second measurement device 3 can measure surfaces and lines constituting characteristic shapes formed within or outside the optical surface of the optical unit 100 and the optical member 10, thereby determining the position and orientation of the characteristic shapes associated with the optical unit 100, etc. When determining the position and orientation of the characteristic shape, a process such as fitting a scale or a figure to the target image is performed to assist the measurement. In addition, by using the stage 3b to observe from various directions while changing the orientation of the optical unit 100 and the optical member 10, the measurement accuracy of the characteristic shape can be improved.

[0056] The information processing device 4 is a computer and includes an arithmetic processing device 4a and a storage device 4b. The arithmetic processing device 4a calculates unified measurement information about the shapes and arrangement of the optical unit 100 and optical members 10 based on the surface measurement data obtained by the first measurement device 2 and the shape measurement data obtained by the second measurement device 3, and stores the calculation results in the storage device 4b. The information processing device 4 evaluates the optical shape of the optical members 10 based on the surface measurement data about the multiple optical members 10 obtained by the first measurement device 2, and evaluates the arrangement accuracy and assembly accuracy of the optical members 10 that constitute the optical unit 100, or the optical characteristics of the optical unit 100, etc., based on the shape measurement data of each part of the optical unit 100, etc., obtained by the second measurement device 3.

[0057] Specific measurements will be described. First, a first measuring device 2 shown in FIG. 11 is used to measure the multiple optical surfaces constituting each optical member 10 before assembly. Specifically, the optical surfaces constituting the optical member 10 are, for example, the entrance surface 21a and the exit surface 21b in the case of lens 21p, the entrance surface 21c and the exit surface 21d in the case of lens 21q, the entrance surface 22a, the internal reflection surface 22b, and the exit surface 22c in the case of prism mirror 22, the entrance surface 23a and the exit surface 23b in the case of wedge-shaped optical element 23, and the reflection surface 25a in the case of see-through mirror 25. When measuring the multiple optical surfaces constituting each optical member 10, for example, measurement reference members 11-15 or other measurement reference members can be used to determine the relative positions of the multiple optical surfaces constituting each optical member 10 via the measurement reference members.

[0058] Next, after assembling the optical unit 100 from the multiple optical members 10, the multiple measurement reference members 11-15 provided in the optical unit 100 are collectively measured using a second measurement device 3 shown in FIG. 11. By collectively measuring the measurement reference members 11-15 for each optical member 10, i.e., optical members 21p, 21q, 22, 23, and 25, using the second measurement device 3, it is possible to obtain information regarding the relative positional relationships between the first localized coordinates X1, Y1, and Z1, the second localized coordinates X2, Y2, and Z2, the third localized coordinates X3, Y3, and Z3, the fourth localized coordinates X4, Y4, and Z4, and the fifth localized coordinates X5, Y5, and Z5. This relative positional relationship includes the relative positional deviation of origins O2-O5 with respect to origin O1 and the tilt of the other localized coordinates with respect to the first localized coordinates X1, Y1, and Z1. The information processing device 4 can calculate and evaluate the relative rotational and translational amounts of each optical member 10 from the relative positional relationships obtained for the first localized coordinates X1, Y1, Z1, the second localized coordinates X2, Y2, Z2, the third localized coordinates X3, Y3, Z3, the fourth localized coordinates X4, Y4, Z4, and the fifth localized coordinates X5, Y5, Z5. That is, the arrangement and orientation of each optical member 10 constituting the optical unit 100 can be determined based on a single common localized coordinate, specifically, for example, the localized coordinates X1, Y1, Z1, and the optical performance of the optical unit 100 can be comprehensively evaluated. Note that, although it is desirable for the origins O1 to O5 to be on the same plane from the viewpoint of facilitating measurement, they may be positioned slightly offset in the X direction.

[0059] It is possible to temporarily assemble multiple optical elements 10 into the optical unit 100 and perform measurements while introducing various slight misalignments. Imaging characteristics, such as distortion, can be measured and stored in a database when the relative positional relationship between the measurement reference elements 11, 12, 13, 14, and 15 varies. By using such a database, the image formed on the first image element 41a of the assembled optical unit 100 can be corrected to offset the distortion based on the relative positional misalignment obtained by measuring the optical elements 21p, 21q, 22, 23, and 25. The image correction is performed, for example, by the control device 92. That is, the control device 92 corrects the image displayed on the first image element 41a based on the deviation from the basic relative positional relationship between the multiple optical elements 21p, 21q, 22, 23, and 25. In this case, a virtual image with improved accuracy can be formed while allowing for the relative positional misalignment between the optical elements 21p, 21q, 22, 23, and 25.

[0060] 12, an example of a method for measuring, using a unified standard, multiple optical surfaces constituting prism mirror 22, which is one of optical members 10. Prism mirror 22 includes a main body 51 having a contour similar to a triangular prism, and a pair of frames 52 (only one of which is shown) provided on both ends of main body 51 in the ±X directions.

[0061] As described above, the main body 51 has multiple optically effective surfaces, including the incident surface 22a, the internal reflecting surface 22b, and the exit surface 22c. The incident axis XP1 on the outside of the incident surface 22a, the principal axis XP3 of the internal reflecting surface 22b, and the exit axis XP2 of the exit surface 22c are all on the same plane but are inclined relative to one another. Here, the principal axis XP3 of the internal reflecting surface 22b corresponds to the bisector of the optical axis before and after passing through the inside of the main body 11 and being reflected by the internal surface of the internal reflecting surface 22b. The direction Da reflecting the incident axis XP1 of the incident surface 22a and the direction Dc reflecting the exit axis XP2 of the exit surface 22c form an angle of 90° or less with respect to each other. On the other hand, the direction Da reflecting the incident axis XP1 of the incident surface 22a or the direction Dc reflecting the exit axis XP2 of the exit surface 22c forms an angle of 90° or more with respect to the direction Db reflecting the principal axis XP3 of the internal reflecting surface 22b.

[0062] The frame 52 has protrusions 54 formed on the incident surface 22a and the exit surface 22c. The optical surface-side surface 54a of the protrusion 54 reduces the step between the outer edge OE1 of the incident surface 22a and the outer edge OE3 of the exit surface 22c in the directions Da and Dc. Therefore, the incident surface 22a and the surface 54a arranged nearby can be positioned within the same measurement area and can be measured simultaneously in non-contact measurements using a microscope or the like, or contact measurements using a probe or the like. Reducing the step formed around the outer edge OE1 of the incident surface 22a and the outer edge OE3 of the exit surface 22c in this way makes it easier to simultaneously measure the incident surface 22a, the exit surface 22c, and the surface 54a arranged nearby.

[0063] A portion of the protrusion 54 near the boundary between the incident surface 22a and the exit surface 22c serves as a measurement reference member 16 that provides a reference for the arrangement of the incident surface 22a and the exit surface 22c, and includes a measurement reference shape 16a. The measurement reference shape 16a includes three measurement reference surfaces LS11, LS12, and LS13 and three measurement reference lines LL11, LL12, and LL13. Here, the measurement reference line LL11 corresponds to the intersection line of the pair of measurement reference surfaces LS11 and LS12, the measurement reference line LL12 corresponds to the intersection line of the pair of measurement reference surfaces LS12 and LS13, and the measurement reference line LL13 corresponds to the intersection line of the pair of measurement reference surfaces LS13 and LS11. The measurement reference shape 16a provides an origin OP1 and local coordinates x1, y1, and z1 with respect to the first surface F1 that includes the incident surface 22a and the exit surface 22c. The local coordinates x1, y1, and z1 correspond to the overall Cartesian coordinate system X, Y, and Z rotated around the X axis. In the illustrated example, the local coordinate x1 is on an extension of the measurement reference line LL11, the local coordinate y1 coincides with the measurement reference line LL12, and the local coordinate z1 is on an extension of the measurement reference line LL13.

[0064] The surface 52b on the optical surface side of the frame 52 has a reduced step with the outer edge OE2 of the internal reflective surface 22b in the direction Db. Therefore, the internal reflective surface 22b and the surface 52b arranged in the vicinity thereof can be arranged in the same measurement area and can be the subject of simultaneous measurement in non-contact measurement using a microscope or the like or contact measurement using a probe or the like. In this way, by reducing the step formed around the outer edge OE2 of the internal reflective surface 22b, it becomes easier to measure the internal reflective surface 22b and the surface 52b arranged in the vicinity thereof simultaneously, particularly in contact measurement.

[0065] A portion of the frame 52 on the inner reflective surface 22b side serves as a measurement reference member 17 that provides a reference for the positioning of the inner reflective surface 22b, and includes an overall reference shape 17a. The overall reference shape 17a corresponds to a datum reference, which is a design reference for the prism mirror 22. The overall reference shape 17a includes three measurement reference surfaces LS21, LS22, and LS23, and three measurement reference lines LL21, LL22, and LL23. Here, the measurement reference line LL21 corresponds to the intersection line of the pair of measurement reference surfaces LS21 and LS22, the measurement reference line LL22 corresponds to the intersection line of the pair of measurement reference surfaces LS22 and LS23, and the measurement reference line LL23 corresponds to the intersection line of the pair of measurement reference surfaces LS23 and LS21. The measurement reference shape 17a defines an origin OP2 and local coordinates x2, y2, and z2 with respect to the second surface F2, which includes the inner reflective surface 22b. The local coordinates x2, y2, and z2 correspond to the overall Cartesian coordinate system X, Y, and Z rotated around the X axis. In the illustrated example, the local coordinate x2 is on an extension of the measurement reference line L21, the local coordinate y2 is on an extension of the pair of measurement reference lines LL22, and the local coordinate z2 is on an extension of the measurement reference line LL23.

[0066] Specific measurements of the prism mirror 22 will now be described. First, the first surface F1 of the prism mirror 22 is measured using the first measurement device 2 shown in FIG. 11. The measurement results of the first surface F1 of the prism mirror 22 include information about the three-dimensional shapes of the entrance surface 22a and the exit surface 22c, as well as information about the three-dimensional shape of the measurement reference shape 16a. The information processing device 4 determines reference information for the first surface F1 (specifically, the origin OP1 and local coordinates x1, y1, z1) from the three-dimensional shape of the measurement reference shape 16a, and converts the three-dimensional shapes of the entrance surface 22a and the exit surface 22c into coordinate information based on the local coordinates x1, y1, z1. This coordinate conversion utilizes a known coordinate conversion method, i.e., calculation processing using matrices and vectors such as rotation and translation. Next, the second surface F2 of the prism mirror 22 is measured using the first measurement device 2. The measurement results of the second surface F2 of the prism mirror 22 include information about the three-dimensional shape of the internal reflection surface 22b and information about the three-dimensional shape of the measurement reference shape 17a. The information processing device 4 determines reference information for the second surface F2 (specifically, the origin OP2 and local coordinates x2, y2, z2) from the three-dimensional shape of the measurement reference shape 17a, and converts the three-dimensional shape of the internal reflection surface 22b into coordinate information based on the local coordinates x2, y2, z2. A known coordinate conversion method is used for this coordinate conversion. Then, the second measurement device 3 shown in FIG. 11 is used to simultaneously measure the measurement reference shape 16a of the first surface F1 and the measurement reference shape 17a of the second surface F2. Measurement using the second measuring device 3 can acquire information regarding the relative positional relationship between the local coordinates x1, y1, z1 and the local coordinates x2, y2, z2, and the information processing device 4 can calculate and evaluate the relative rotation and translational movement amounts between the local coordinates x1, y1, z1 and the local coordinates x2, y2, z2. This makes it possible to determine the three-dimensional shapes of the entrance surface 22a, the internal reflection surface 22b, and the exit surface 22c based on the common single local coordinates x2, y2, z2, that is, based on a datum, and to determine the relative positional relationship between the entrance surface 22a, the internal reflection surface 22b, and the exit surface 22c, thereby enabling a comprehensive evaluation of the optical performance of the prism mirror 22.

[0067] The above has been a description of the measurement of the prism mirror 22, but similar measurements are possible for the wedge-shaped optical element 23. In this case, measuring the entrance surface 23a of the wedge-shaped optical element 23 corresponds to measuring the entrance surface 22a and exit surface 22c of the prism mirror 22, and measuring the exit surface 23b of the wedge-shaped optical element 23 corresponds to measuring the internal reflection surface 22b of the prism mirror 22. In other words, the entrance surface 23a is measured together with the shape corresponding to the measurement reference shape 16a, and the exit surface 23b is measured together with the shape corresponding to the measurement reference shape 17a. This makes it possible to determine the relative positional relationship between the entrance surface 23a and the exit surface 23b of the wedge-shaped optical element 23, thereby enabling a comprehensive evaluation of the optical performance of the prism mirror 22. Although detailed description will be omitted for the lenses 21p, 21q, and see-through mirror 25, measurements similar to those for the wedge-shaped optical element 23 are possible.

[0068] The optical unit 100 and virtual image display device (i.e., HMD 301) according to the first embodiment described above include a plurality of optical members 10 (see FIG. 5 ). The plurality of optical members 10 each have measurement reference members 11-15 at their non-connected portions, which provide a reference for placement. The measurement reference members 11-15 of the plurality of optical members 10 are aligned in the same direction, either because they provide a reference based on their shape characteristics or because of their relative positional relationship. In this case, because the measurement reference members 11-15 that provide a reference for placement of the plurality of optical members 10 are aligned in the same direction, it is possible to easily and accurately grasp the relative positional relationship of each optical member 10 in a product assembled from the plurality of optical members 10, i.e., the assembly accuracy. This facilitates feedback, such as correction of optical components and correction of the display state, and makes it easier to ensure and improve the image quality of the virtual image.

[0069] A modified example will be described with reference to FIG. 13. FIG. 13 is a diagram showing the prism mirror 22 side of the second lens 21q, illustrating an example in which the location of the second measurement reference member 12 has been changed. The second measurement reference member 12 is formed on the flange portion 21f (i.e., the frame FL2) of the second lens 21q. However, the second measurement reference member 12 is not exposed on the side surface of the second lens 21q. In other words, the second measurement reference member 12 faces the prism mirror 22 and, after assembly, is hidden by the tab 21y and cannot be observed from the outside. The second measurement reference member 12 of the modified example is also a member formed accompanying the second lens 21q, and includes three measurement reference surfaces RS21, RS22, and RS23 and three measurement reference lines RL21, RL22, and RL23 as a measurement reference shape.

[0070] 13, in the assembled optical unit 100, the second measurement reference member 12 is disposed internally and cannot be observed externally. However, its internal location facilitates avoiding an increase in the size of the optical unit 100. Even when the second measurement reference member 12 is disposed internally, the location and orientation of the second measurement reference member 12 can be measured using X-ray CT or other fluoroscopic measurement techniques, allowing the placement accuracy and assembly accuracy of the second lens 21q to be measured with high accuracy. For optical members 21p, 22, 23, and 25 other than the second lens 21q, measurement reference members 11, 13, 14, and 15 are disposed internally, and the measurement reference members 11, 13, 14, and 15 can be measured externally using X-ray CT or other fluoroscopic measurement techniques, allowing the placement accuracy and assembly accuracy of the optical members 21p, 22, 23, and 25 to be measured, allowing the optical characteristics of the optical unit 100 to be evaluated.

[0071] 13 is preferably positioned to avoid the connection between components that would be hidden by the adhesion of the second lens 21q, specifically the connection points provided inside the claws 21y, etc. Avoiding the connection points can improve the accuracy and reliability of fluoroscopic observation.

[0072] [Second embodiment] Hereinafter, an optical unit and a virtual image display device according to a second embodiment of the present invention will be described. Note that the optical unit and the like of the second embodiment are partially modified versions of the optical unit and the like of the first embodiment, and a description of the common parts will be omitted.

[0073] Fig. 14 shows an optical unit 100 of the second embodiment. In Fig. 14, area GR1 is a front view of the optical unit 100, and area GR2 is a side view of the optical unit 100. In this case, the shapes and arrangements of the fourth measurement reference member 14 and the fifth measurement reference member 15 are different from those of the first embodiment.

[0074] 15, in the optical unit 100 of the second embodiment, the fourth measurement reference member 14 is associated with the wedge-shaped optical element 23, as in the first embodiment, and includes measurement reference surfaces RS41, RS42, and RS43 and measurement reference lines RL41, RL42, and RL43. The fourth measurement reference member 43 provides an origin O4 and local coordinates X4, Y4, and Z4 with respect to the arrangement and attitude of the wedge-shaped optical element 23. By design, the orientations of the local coordinates X4, Y4, and Z4 do not coincide with the orientations of the local coordinates X1, Y1, and Z1 of the first measurement reference member 12.

[0075] The fifth measurement reference member 15 is associated with the see-through mirror 25 or the first combiner 103a, as in the first embodiment, and includes measurement reference surfaces RS51, RS52, and RS53 and measurement reference lines RL51, RL52, and RL53. The fifth measurement reference member 15 provides an origin O5 and local coordinates X5, Y5, and Z5 for the arrangement and attitude of the wedge-shaped optical element 23. In design, the orientations of the local coordinates X5, Y5, and Z5 are aligned with the local coordinates X4, Y4, and Z4 of the fourth measurement reference member 14, but measurements are performed on the assumption that, strictly speaking, the orientations do not match the local coordinates X4, Y4, and Z4 in the actual object.

[0076] As is clear from the above, the orientation of the coordinate systems is uniform for the first measurement reference member 11, the second measurement reference member 12, and the third measurement reference member 13. Furthermore, the orientation of the coordinate systems of the fourth measurement reference member 14 and the fifth measurement reference member 15 is uniform, although they are different from the first measurement reference member 11, etc. That is, in the first optical member group G1 including the first lens 21p, the second lens 21q, and the prism mirror 22, the first measurement reference member 11, the second measurement reference member 12, and the third measurement reference member 13 formed thereon are uniformly oriented in a specific direction, while in the second optical member group G2 including the wedge-shaped optical element 23 and the see-through mirror 25, the fourth measurement reference member 14 and the fifth measurement reference member 15 formed thereon are uniformly oriented in a direction different from the specific direction. In other words, the plurality of measurement reference members 11, 12, and 13 formed on the plurality of optical members 21p, 21q, and 22 constituting the first optical member group G1 are unified in a specific first direction in the sense of providing a reference based on their geometric characteristics, and the plurality of measurement reference members 14 and 15 formed on the plurality of optical members 23 and 25 constituting the second optical member group G2 are unified in a different direction from the measurement reference members 11, 12, and 13 and are unified in a second direction in the sense of providing a reference based on their geometric characteristics. In this case, it becomes easy to perform collective measurement of the first optical member group G1 from the first lens 21p to the prism mirror 22, and it becomes easy to perform collective measurement of the second optical member group G2 from the wedge-shaped optical element 23 to the see-through mirror 25. By dividing the optical system into a first optical member group G1 at the front stage and a second optical member group G2 at the rear stage, the measurement standard is divided before and after the optical path of the image light ML is significantly bent by the prism mirror 22, making it relatively easy to manufacture and measure the measurement standard members 11, 12, 13, 14, and 15, and also making it easier to ensure measurement accuracy on a group-by-group basis or as a whole.

[0077] The optical unit 100 and virtual image display device (i.e., HMD 301) according to the second embodiment described above include a first optical member group G1 including a plurality of optical members 21p, 21q, and 22, and a second optical member group G2 including a plurality of other optical members 23 and 25, which are formed separately from the first optical member group G1 with a plurality of other measurement reference members 14 and 15 that are unified in a different direction from the plurality of measurement reference members 11, 12, and 13. In this case, the positional relationship of the optical members 21p, 21q, and 22 or the optical members 23 and 25 that constitute each of the optical member groups G1 and G2 can be measured for each of the optical member groups G1 and G2.

[0078] 16 is a conceptual diagram illustrating a modification of the optical unit 100 of FIG. 15. In this modification, the third measurement reference member 13 is associated with the see-through mirror 25, as in the first embodiment, and includes measurement reference surfaces RS31, RS32, and RS33 and measurement reference lines RL31, RL32, and RL33. The third measurement reference member 13 provides an origin O3 and local coordinates X3, Y3, and Z43 with respect to the arrangement and attitude of the wedge-shaped optical element 23. By design, the orientations of the local coordinates X3, Y3, and Z3 do not coincide with the orientations of the local coordinates X1, Y1, and Z1 of the first measurement reference member 12, but do coincide with the orientations of the local coordinates X4, Y4, and Z4 of the fourth measurement reference member 14. As a result, the plurality of measurement reference members 11, 12 formed on the plurality of optical members 21p, 21q constituting the first optical member group G1 are aligned in a specific direction, and the plurality of measurement reference members 13, 14, 15 formed on the plurality of optical members 22, 23, 25 constituting the second optical member group G2 are aligned in a different direction from the measurement reference members 11, 12. In this case, the wedge-shaped optical element 23 and the see-through mirror 25, which include reflective surfaces, are grouped together in the same second optical member group G2, making it possible to focus on understanding the positional relationship between reflective surfaces that have a large impact on display quality (i.e., the internal reflective surface 22b and the reflective surface 25a).

[0079] [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.

[0080] The shapes of the measurement reference members 11, 12, 13, 14, and 15 are not limited to triangular pyramids, but can be various shapes combining flat surfaces or edges. The measurement reference members 11, 12, 13, 14, and 15 do not need to be single structures but may be composed of multiple parts, such as a combination of multiple spherical surfaces or vertices to define a specific surface. The contour shapes and optically effective surface shapes of the optical members 21p, 21q, 22, 23, and 25 are not limited to those shown in the drawings and can be modified as appropriate depending on the application. Furthermore, the measurement reference member may be omitted for any specific optical member among the optical members 21p, 21q, 22, 23, and 25.

[0081] If, as a result of measuring the positional relationship of the measurement reference members 11, 12, 13, 14, and 15, the relative deviation is found to be greater than the allowable value and is different from the standard value, the optical members 21p, 21q, 22, 23, and 25 can be assembled so as to reduce the relative deviation when manufacturing the next optical unit 100. Alternatively, the optical members 21p, 21q, 22, 23, and 25 can be temporarily assembled, and the positional relationship of the measurement reference members 11, 12, 13, 14, and 15 can be measured and adjusted to reduce the error, and finally the fixation of the optical members 21p, 21q, 22, 23, and 25 can be confirmed.

[0082] The imaging characteristics obtained while changing the relative positional relationship of the measurement reference members 11, 12, 13, 14, and 15 are measured and compiled into a database, and the imaging characteristics can be corrected while correcting the relative positional relationship. Note that an image reflecting the relative positional deviation of the optical members 21p, 21q, 22, 23, and 25 may be formed on the imaging element 41a.

[0083] The measurement reference members 11, 12, 13, 14, and 15 are not limited to those in which the planes or lines that specify the direction are arranged in parallel relation to one another, but can also be unified in terms of having a correlation based on a certain angular difference, such as being rotated in 90° increments.

[0084] The optical unit 100 incorporated into the first display device 100a is not limited to the one shown in the figure and can have various configurations. For example, the elements constituting the optical unit 100 shown in Fig. 11 are merely examples, and modifications are possible, such as increasing or decreasing the number of lenses, adding mirrors, or adding light-guiding members.

[0085] 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.

[0086] 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.

[0087] In a specific embodiment, the optical unit is an optical unit for imaging that includes a plurality of optical elements, each of which is fixedly positioned at the connected portion and has a measurement reference element at the non-connected portion that provides a reference for positioning.

[0088] The optical unit has measurement reference members at each non-connected section that provide a reference for positioning, making it possible to grasp the relative positions of each optical element in a product assembled from multiple optical elements, i.e., the assembly accuracy. This facilitates feedback such as correction of optical components and correction of display conditions, making it easier to ensure and improve the image quality of virtual images.

[0089] In a specific aspect, the orientation of the plurality of measurement reference members is unified, and in this case, the assembly accuracy of each optical member can be easily grasped with high accuracy.

[0090] In a specific aspect, the plurality of measurement reference members have a measurement reference shape including a plurality of planes or an intersection line of the plurality of planes, in which case the reference defined by the measurement reference members is specified as coordinate information by the plurality of planes or the intersection line of the plurality of planes.

[0091] In a specific aspect, the plurality of measurement reference members are formed on frames provided outside the plurality of optical members, respectively.

[0092] In a specific aspect, the measurement reference member is a protruding portion formed on the frame of the optical member, in which case the frame of the optical member can be effectively used to measure the positional relationship of each optical member.

[0093] In a specific aspect, the plurality of measurement reference members can be observed collectively in appearance, and in this case, the positional relationship of the plurality of measurement reference members can be measured collectively with high accuracy using an optical measurement method.

[0094] In a specific aspect, the optical element measuring device includes a first optical element group including a plurality of optical elements, and a second optical element group including a plurality of other optical elements, each of which is formed with a plurality of other measurement reference elements that are unified in a different direction from the plurality of measurement reference elements, separate from the first optical element group. In this case, the positional relationship of the optical elements that make up the optical element group can be measured for each optical element group.

[0095] In a specific aspect, the plurality of optical members include a first optical member, a second optical member, and a third optical member, the first optical member and the second optical member being fixed, the second optical member and the third optical member being fixed, the first optical member, the second optical member, and the third optical member having a first measurement reference member, a second measurement reference member, and a third measurement reference member at non-connected portions, respectively, and the first measurement reference member, the second measurement reference member, and the third measurement reference member are oriented in the same direction. In this case, the assembly accuracy of the first to third optical members can be easily determined with high accuracy.

[0096] A virtual image display device in a specific embodiment includes an image element that emits image light, and the above-described optical unit that forms a virtual image from the image light incident from the image element.

[0097] In a specific embodiment, the virtual image display device further includes a control device that corrects the image displayed on the image element based on the arrangement relationship of the plurality of optical members.

[0098] In a specific embodiment, the method for measuring an optical unit is a method for measuring an optical unit for imaging that includes a plurality of optical elements, each of which has a measurement reference element at a non-connected portion that provides a reference for positioning, the directions of the measurement reference elements of the plurality of optical elements are unified, and the relative positional relationship of the plurality of optical elements is determined by measuring the plurality of measurement reference elements collectively.

[0099] In the above measurement method, the relative positional relationship of multiple optical components is determined by simultaneously measuring multiple measurement reference components with uniform orientation, making it possible to easily and accurately grasp the assembly accuracy of a product made up of multiple optical components, facilitating feedback such as correction of optical components and correction of display conditions, and making it easier to ensure and improve the image quality of virtual images. [Explanation of symbols]

[0100] 10...optical element, 11, 12, 13, 14, 15...measurement reference member, 21...projection lens, 21p, 21q...lens, 21f, 21n...flange portion, 22...prism mirror, 22f...flange portion, 23...wedge-shaped optical element, 23f...flange portion, 25...see-through mirror, 25c...mirror film, 30...optical block, 31...barrel, 41a, 41b...image element, 61a, 61b...frame, 62...end, 63...protrusion, 83...support plate, 83a...upper edge, 83d...rib, 100...optical unit, 100a, 100b...display device, 102a, 102b...display driver, 103a, 103b...combiner, 300...image display device, AX...optical axis, AX1, AX2, AX 3...optical axis part, EY...eye, FL1 to F5...frame, G1, G2...optical component group, ML...image light, O1 to O5...origin, OL...external light, P1, P2, P3...optical path, PP...pupil position, RL11 to RL13, RL21 to RL23, RL31 to RL33, RL41 to RL43, RL51 to RL53...measurement reference line, RS11 to RS13, RS21 ~RS23, RS31~RS33, RS41~RS43, RS51~RS53...measurement reference plane, US...wearer, X, Y, Z...orthogonal coordinate system, X1, Y1, Z1...first local coordinate, X2, Y2, Z2...second local coordinate, X3, Y3, Z3...third local coordinate, X4, Y4, Z4...fourth local coordinate, X5, Y5, Z5...fifth local coordinate

Claims

1. An optical unit for imaging including a plurality of optical members, The plurality of optical members are fixedly arranged at the connection portions and are arranged independently at the non-connection portions. each having a measurement reference member that provides a reference for The plurality of measurement reference members are measurement reference members including any of a plurality of planes and intersections of the plurality of planes. An optical unit having a fixed reference shape.

2. The optical unit according to claim 1 , wherein the plurality of measurement reference members are aligned in the same direction.

3. The plurality of measurement reference members are formed on frames provided outside the plurality of optical members, respectively. The optical unit according to any one of claims 1 to 2,

4. The measurement reference member is a protruding portion formed on the frame of the optical member. The optical unit described.

5. The plurality of measurement reference members are externally observable collectively.

10. The optical unit according to claim 1 ,

6. a first optical member group including the plurality of optical members; and a second optical member group including the plurality of optical members, the first optical member group being separate from the first optical member group. A plurality of other measurement reference members are formed in a direction different from that of the measurement reference member. and a second optical member group including a plurality of other optical members. Item 1. An optical unit according to item 1.

7. the plurality of optical members include a first optical member, a second optical member, and a third optical member; The first optical member and the second optical member are fixed, and the second optical member and the third optical member are fixed. The materials are fixed, The first optical member, the second optical member, and the third optical member each include a first measurement a reference member, a second measurement reference member, and a third measurement reference member in the non-connected portion; The first measurement reference member, the second measurement reference member, and the third measurement reference member directions are The optical unit according to claim 1 , wherein the directions are uniform.

8. An imaging element that emits imaging light; Measurement points that are fixedly positioned at the connection and provide a reference for positioning at the non-connection a plurality of optical members each having a quasi-member, and an optical unit that forms a virtual image; Equipped with The plurality of measurement reference members are formed on frames provided outside the plurality of optical members, respectively. A virtual image display device.

9. an image element that emits image light; 8. The imaging device according to claim 1, wherein the imaging light incident from the imaging element is formed as a virtual image. The optical unit according to item A virtual image display device comprising:

10. The image to be displayed on the image element is corrected based on the arrangement relationship of the plurality of optical members. The virtual image display device according to claim 9 , further comprising a control device.

11. an optical unit for imaging including a plurality of optical members; The plurality of optical members are fixedly arranged at the connection portions and are arranged independently at the non-connection portions. Each of the measuring units has a measurement reference member that provides a reference for the measurement. Virtual image display device.

Images