Patent Application
20240036320
The present application is based on, and claims priority from JP Application Serial Number 2022-122356, filed Jul. 29, 2022, the disclosure of which is hereby incorporated by reference herein in its entirety.
The present disclosure relates to an image display device and an optical unit that enable observation of a virtual image.
There is an image display device including a display element that displays an image, an ocular prism that guides image light from the display element to an optical pupil and allows the outside world to be seen therethrough, and a housing that contains and holds the display element and part of the ocular prism, wherein a packing is provided so as to be in contact with the periphery of the ocular prism and the housing.
Image light is made incident on an end portion of an ocular prism in a device disclosed in JP-A-2009-157291. In an image display device of the type in which the image light is made incident on one surface of a combiner that enables the outside world to be seen, an optical path from an optical element on the upstream side of the combiner to the one surface of the combiner is exposed. Thus, the optical element needs to be protected.
An image display device according to an aspect of the present disclosure includes: an image element, a first optical member disposed on a light emission side of the image element, a second optical member including an incident surface disposed on the light emission side of the first optical member, a reflection surface configured to bend an optical axis, and an emitting surface, and a barrel configured to accommodate the first optical member and hold the second optical member, wherein the emitting surface of the second optical member is exposed through an opening of the barrel, and an outer edge of the emitting surface is surrounded by an edge portion of the opening.
Next, an image display device according to an embodiment of the present disclosure will be described with reference to
The HMD 200 includes a first display device 100A for the right eye, a second display device 100B for the left eye, a pair of temple type support devices 100C that support the display devices 100A and 100B, and a user terminal 90 that is an information terminal. The first display device 100A includes: a first display drive part 102a that is disposed at an upper portion thereof and independently functions as an image display device, and a first combiner 103a that has a spectacle lens shape and covers the front of the eye. The second display device 100B similarly includes: a second display drive part 102b that is disposed at an upper portion thereof and independently functions as an image display device, and a second combiner 103b that has a spectacle lens shape and covers the front of the eye. The support devices 100C are each a mounted member mounted to the head of the wearer US, and supports the upper end side of the pair of combiners 103a and 103b via the display drive parts 102a and 102b integrated in external view. The first display device 100A and the second display device 100B are optically the same or are inverted left and right, and hereinafter, the detailed description on the second display device 100B will be omitted.
The barrel 41 that supports the optical members 2a and 2b constituting the first projection optical system 12a is supported by a first frame 52a and is disposed on the lower side of the first frame 52a. The first frame 52a is covered by a cover 71, and the barrel 41 is also entirely covered by the cover 71. The first frame 52a is formed of a metal material. The barrel 41 and the cover 71 are formed of a light-shielding resin material, and one surface of the prism mirror 22 is exposed through an opening 410 of the barrel 41. The barrel 41 has a barrel cover 41u of the upper portion for example, in contact with the first frame 52a in a fitted manner, to be fixed in a state of being suspended from the first frame 52a. As a result, the first display part 20a is fixed in a state of being suspended from the first frame 52a via the barrel 41. The first frame 52a has, on the upper side, a recess RE for arranging the first circuit member 80a.
In the first display device 100A, the first image element 11a is a spontaneous light emission type image light generating device. The first image element 11a emits the image light ML to the first projection optical system 12a. The barrel 41 accommodates and supports the first image element 11a together with the optical elements constituting the first projection optical system 12a. The first image element 11a is, for example, an organic electroluminescence (EL) display, and forms a color still image or moving image on a two-dimensional display surface 11d. The first image element 11a is driven by the first circuit member 80a, in particular, a display control device 88 to perform a display operation. The first image element 11a is not limited to the organic EL display, and can be replaced with a display device using inorganic EL, an organic LED, an LED array, a laser array, a quantum dot light emission element, or the like. The first image element 11a is not limited to the spontaneous light emission type image light generating device, may include an LCD or another light modulation element, and may form an image by illuminating the light modulation element with a light source such as a backlight. As the first image element 11a, a liquid crystal on silicon (LCOS) (LCoS is a registered trademark), a digital micro-mirror device, or the like may be used instead of the LCD. A device obtained by omitting the display control device 88 from the first display device 100A is also referred to as the image display device 100.
In the first display part 20a, the optical path portion P1 from the projection lens 21 to the reflection surface 22b extends upward slightly obliquely or in a direction close to being parallel to the Z direction, toward the backward side from the viewpoint. The optical path portion P2 from the reflection surface 22b to the see-through mirror 23 extends downward obliquely toward the front side. The optical path portion P2 is inclined more than the optical path portion P1 relative to the horizontal direction (X-Z plane). The optical path portion P3 from the see-through mirror 23 to the pupil position PP extends in the upward direction slightly obliquely or a direction close to being parallel to the Z direction toward the backward side. In the illustrated example, a portion of the optical axis AX corresponding to the optical path portion P3 is about −10°, where a downward orientation in the +Z direction is negative. Thus, the partially transmissive mirror 123 reflects the image light ML, with the optical axis AX or the optical path portion P3 directed upward by a predetermined angle, that is, upward by about 10°. As a result, an emission optical axis EX that is an extension of the optical axis portion AX3 corresponding to the optical path portion P3 is inclined downward by about 10° with respect to a center axis HX parallel to the +Z direction on the front side and extends. This is because a line of sight of a human being is stable in a slightly lowered eye state in which the line of sight is inclined downward by approximately 10° with respect to a horizontal direction. The center axis HX that extends in the horizontal direction with respect to the pupil position PP assumes a case in which the wearer US wearing the first display device 100A relaxes in an upright posture and faces the front and gazes at the horizontal direction or the horizontal line.
In the first display part 20a, the projection lens 21 includes a first lens 21o, a second lens 21p, and a third lens 21q. The projection lens 21 receives the image light ML emitted from the first image element 11a and makes the image light ML incident on the prism mirror 22. The projection lens 21 focuses the image light ML emitted from the first image element 11a into a state close to a parallel luminous flux. The first lens 21o, the second lens 21p, and the third lens 21q, constituting the projection lens 21, respectively include an incident surface 21a and an emitting surface 21b, an incident surface 21c and an emitting surface 21d, and an incident surface 21e and an emitting surface 21f that are freely-curved surfaces or aspherical surfaces The optical surfaces 21a, 21b, 21c, 21d, 21e, and 21f are asymmetrical about the optical axis AX relative to the longitudinal direction, which is parallel to the Y-Z plane and crosses the optical axis AX, and are symmetrical about the optical axis AX relative to the transverse direction or the X direction. The first lens 21o, the second lens 21p, and the third lens 21q are formed of resin for example, but may also be formed of glass. An antireflection film can be formed on the optical surfaces of the first lens 21o, the second lens 21p, and the third lens 21q constituting the projection lens 21.
The prism mirror 22 is an optical member having a refractive and reflection function that is a function of combining a mirror and a lens, and reflects the image light ML from the projection lens 21 while refracting it. The prism mirror 22 includes the incident surface 22a disposed on the light emission side of the first optical member, the reflection surface 22b for bending the optical axis AX, and the emitting surface 22c disposed in a direction opposite to the reflection surface 22b and symmetrical to the incident surface 22a. The prism mirror 22 emits the image light ML incident from the front where the projection lens 21 is disposed, such that it is bent in a direction inclined downward with respect to a direction in which an incident direction is reversed (a direction of the light source seen from the prism mirror 22). The incident surface 22a, the reflection surface 22b, and the emitting surface 22c, which are optical surfaces forming the prism mirror 22, are asymmetrical about the optical axis AX relative to the longitudinal direction, which is parallel to the Y-Z plane and crosses the optical axis AX, and are symmetrical about the optical axis AX relative to the transverse direction or the X direction. The optical surface of the prism mirror 22, that is, the incident surface 22a, the reflection surface 22b, and the emitting surface 22c are, for example, freely-curved surfaces. The incident surface 22a, the reflection surface 22b, and the emitting surface 22c are not limited to freely-curved surfaces, and may be aspherical surfaces. The prism mirror 22 may be formed of, for example, a resin, but may also be formed of glass. The reflection surface 22b is not limited to one that reflects the image light ML by total reflection, and may be a reflection surface formed of a metal film or a dielectric multilayer film. In this case, for example, a reflection film formed of a single layer film or multilayer film formed of a metal such as Al or Ag is formed on the reflection surface 22b by vapor deposition or the like, or a sheet-shaped reflection film formed of a metal is affixed thereto. Although detailed illustration is omitted, an antireflection film can be formed on the incident surface 22a and the emitting surface 22c.
The emitting surface 22c of the prism mirror 22 is concave as a whole, is concave on an off-axis plane parallel to the Y-Z plane and through which the optical axis portions AX1 to AX3 pass, that is, on the paper plane, and is also concave in a cross section CS (see
The emitting surface 22c of the prism mirror 22 is substantially parallel to the optical axis portion AX2 on the inner surface side of the intersecting position of the optical axis portion AX2. Thus, the amount of refraction on the emitting surface 22c can be reduced, and an increase in aberration can be suppressed. An inclination δ of the emitting surface 22c on the inner surface side of the intersecting position of the optical axis portion AX2 corresponds to an angle formed by the optical axis portion AX2 and the cross section CS perpendicular to the emitting surface 22c at the intersecting position of the optical axis portion AX2, and is, for example, ° or less.
The see-through mirror 23, that is, the first combiner 103a is a curved plate-shaped reflective optical member that functions as a concave surface mirror, and partially reflects the image light ML from the prism mirror 22, and partially transmits outside light OL. The see-through mirror 23 reflects the image light ML from the prism mirror 22 toward a pupil position PP. The see-through mirror 23 has a reflection surface 23c and an outer side surface 23o.
The see-through mirror 23 is a concave mirror that covers the pupil position PP at which the eye EY or the pupil is disposed, has a concave shape toward the pupil position PP, and has a convex shape toward the outside. The pupil position PP or its opening PPa is referred to as eye point or eye box. The pupil position PP or the opening PPa corresponds to an emission pupil EP on the emission side of the first display part 20a. The see-through mirror 23 is a collimator, and converges the main rays of the image light ML spread after the imaging in the vicinity of the emission side of the prism mirror 22 of the first projection optical system 12a, which are the main rays of the image light ML emitted from each of points on the display surface 11d, at the pupil position PP. The see-through mirror 23 serves as a concave mirror to enable magnified view of the intermediate image IM formed on the first image element 11a as the image light generating device and re-imaged by the first projection optical system 12a. More specifically, the see-through mirror 23 functions in the same manner as a field lens, and causes the image light ML from each point of the intermediate image IM formed behind the emitting surface 22c of the prism mirror 22 to be incident on the pupil position PP in a collimated state so as to be collected as a whole. The see-through mirror 23 is disposed between the intermediate image IM and the pupil position PP, and thus needs to spread to a size that is equal to or larger than the effective area EA corresponding to the angle of view. Here, the angle of view is a combination of viewing angles on the upper, lower, left, and right sides with respect to the optical axis AX extending in the forward direction of the eye, and is set to about 45° diagonally in a specific example. In the see-through mirror 23, an outer region extending to the outside of the effective area EA does not directly affect image formation, and thus can have any surface shape. Still, for ensuring a spectacle lens shape, preferably, the curvature of the outer region is the same as the curvature of the surface shape of the outer edge of the effective area EA, or the curvature of the outer region continuously changes from the outer edge.
The see-through mirror 23 is a semi-transmissive mirror plate having a structure in which a transmissive reflection film 23a is formed on a back surface of a plate-shaped body 23b. The reflection surface 23c of the see-through mirror 23 is asymmetrical about the optical axis AX relative to the longitudinal direction, which is parallel to the Y-Z plane and crosses the optical axis AX, and is symmetrical about the optical axis AX relative to the transverse direction or the X direction. The reflection surface 23c of the see-through mirror 23 is, for example, a freely-curved surface. The reflection surface 23c is not limited to a freely-curved surface, and may be an aspherical surface. The reflection surface 23c needs to spread to a size that is equal to or larger than the effective area EA. When the reflection surface 23c is formed in the outer region wider than the effective area EA, a difference in visibility is less likely to occur between an external image from behind the effective area EA and an external image from behind the outer region.
when the image light ML is reflected, part of the light is reflected by the reflection surface 23c of the see-through mirror 23. Thus, because outside light OL passes through the see-through mirror 23, see-through view of the outside is enabled, and a virtual image can be superimposed on an outside image. At this time, when the plate-shaped body 23b has a thickness of less than or equal to approximately a few millimeters, a change in magnification of the outside image can be curbed to be small. A reflectance of the reflection surface 23c with respect to the image light ML and the outside light OL is set to 10% or more and 50% or less in a range (corresponding to an effective area EA) of an incident angle of the assumed image light ML from the viewpoint of ensuring a brightness of the image light ML and facilitating observation of the external image by see-through. The plate-shaped body 23b which is a base material of the see-through mirror 23 is formed of, for example, a resin, and may also be formed of glass. The plate-shaped body 23b is formed of the same material as the support plate 61 that supports the plate-shaped body 23b from the surrounding thereof, and has the same thickness as the support plate 61. The transmissive reflection film 23a is formed of, for example, a dielectric multilayer film configured of a plurality of dielectric layers having an adjusted film thickness. The transmissive reflection film 23a may be a single-layer film or a multilayer film of a metal such as Al or Ag of which a film thickness has been adjusted. The transmissive reflection film 23a may be formed by laminating using deposition, for example, and may also be formed by affixing a sheet-shaped reflection film. An antireflection film is formed on an outer surface 23o of the plate-shaped body 23b.
In describing the optical path, the image light ML from the first image element 11a is emitted from the projection lens 21 in a state in which it is incident on the projection lens 21 and is substantially collimated. The image light ML that has passed through the projection lens 21 is incident on the prism mirror 22, passes through the incident surface 22a while being refracted by it, is reflected by the reflection surface 22b with a high reflectance close to 100%, and is refracted again by the emitting surface 22c. After the tentative intermediate image IM is formed, the image light ML from the prism mirror 22 is incident on the see-through mirror 23 and is reflected by the reflection surface 23c with a reflectance of about 50% or less. The image light ML reflected by the see-through mirror 23 is incident on the pupil position PP at which the eye EY or pupil of the wearer US is placed. The outside light OL that has passed through the see-through mirror 23 and the support plate 61 therearound is also incident on the pupil position PP. In other words, the wearer US wearing the first display device 100A can observe a virtual image of the image light ML in a state in which it overlaps the external image.
The display control device 88 illustrated in
With reference to
In addition to the first frame 52a and the second frame 52b, a support device 50 includes a joint 50c that couples the first frame 52a and the second frame 52b to relatively fix them. The joint 50c is a member made of metal such as magnesium alloy, and is coupled to one end portion of the first frame 52a using a fastener 50g or the like, and is coupled to the other end portion of the second frame 52b using the fastener 50g or the like. The first frame 52a to which the first display part 20a is attached and the second frame 52b to which the second display part 20b is attached are fixed in a mutually optically aligned state via the joint 50c provided at the center.
A structure of the barrel 41 is described with reference to
The barrel 41 includes a barrel body 41a and a barrel cover 41u, accommodates the first optical member 2a, and holds the second optical member 2b. The barrel body 41a and the barrel cover 41u are formed of polycarbonate resin in consideration of support accuracy and strength for the optical elements fixed inside. The barrel body 41a is a bathtub-shaped container that is open on the upper side and has the opening 410 at part of the bottom. The barrel cover 41u is fixed so as to cover the barrel body 41a from the upper side. The barrel body 41a includes two side plate members 41c, a bottom plate member 41d, a front plate member 41e, and two protruding portions 41f and 41g. The two side plate members 41c extend substantially parallel to an off-axis plane SS (see
On the inner side of one side plate member 41c, there are formed stepped guide projection portions 45a, 45b, 45c, and 45d, as projections for supporting the first lens 21o, the second lens 21p, and the third lens 21q, which constitute the first optical member 2a, and the prism mirror 22 of the second optical member 2b. Although not illustrated, guide projection portions similar to the guide projection portions 45a, 45b, 45c, and 45d are formed on the inner surface of the other side plate member 41c (see
The barrel cover 41u is disposed on the opposite side from the bottom plate member 41d and covers the inside of the barrel body 41a to form an accommodation space IS. The barrel cover 41u includes a top plate 41x and a rear plate 41y. The top plate 41x extends in parallel with the X-Z plane, and the rear plate 41y is disposed to be inclined with respect to the X-Z plane and the X-Y plane so as to cover the outside of the reflection surface 22b of the prism mirror 22 of the second optical member 2b. The rear plate 41y has an inner surface 41m extending along and in the vicinity of the reflection surface 22b of the prism mirror 22. A uniform gap GA is formed between the outer side of the reflection surface 22b and the inner surface 41m of the rear plate 41y. The gap GA defines, for example, an interval of about 0.1 mm to 1 mm.
A fitting structure, such as a step, is provided between an outer edge 42q of the barrel cover 41u and an upper end 42p of the barrel body 41a to achieve mutual alignment for example. The gap between the outer edge 42q of the barrel cover 41u and the upper end 42p of the barrel body 41a may be filled with an adhesive or a sealing material. In this case, the airtightness of the accommodation space IS can be enhanced.
In the barrel 41, a diaphragm plate member 26 is disposed between the first optical member 2a and the second optical member 2b. Preferably, the diaphragm plate member 26 is disposed between the first image element 11a and the intermediate image IM, and at or vicinity of a position of an intermediate pupil where the luminous fluxes from respective points on the display surface 11d have the largest diameter. In the illustrated case, the diaphragm plate member 26 is attached adjacent to the incident surface 22a of the prism mirror 22. Referring to
Notches 26f are provided at four portions of the periphery of the diaphragm plate member 26. The notches 26f fit with four projections 22f formed on the outer side of the incident surface 22a of the prism mirror 22, that is, a side surface 22s side. Thus, the diaphragm plate member 26 is aligned with respect to the incident surface 22a of the prism mirror 22. The diaphragm plate member 26 is fixed to the projections 22f using adhesive around the notches 26f.
In the barrel 41, in a space ISa facing the front plate member 41e, the first image element 11a is inserted from above through a hole 41z and fixed in an aligned state.
Fixing of the second optical member 2b or the prism mirror 22 in the barrel 41 will be described. The prism mirror 22 includes projections 22t on the pair of side surfaces 22s sandwiched between the incident surface 22a, the reflection surface 22b, and the emitting surface 22c. A pair of first support surfaces 28a of the projection 22t on the incident surface 22a side are in contact with a pair of first placement surfaces 48a provided to the guide projection portions 45d formed on the barrel body 41a. A pair of second support surfaces 28b of the projection 22t on the emitting surface 22c side are in contact with a pair of second placement surfaces 48b provided to the guide projection portions 45d formed on the barrel body 41a. A pair of outward facing third support surfaces 28c provided on the lower side of the projections 22t in the side surfaces 22s are in contact with a pair of inwardly facing third placement surfaces 48c provided to the guide projection portions 45d formed on the barrel body 41a. By means of the contact between the first support surfaces 28a and the first placement surfaces 48a, the prism mirror 22 can be aligned in terms of the position in the Z direction and inclination around the Y axis and the X axis. By means of the contact between the second support surfaces 28b and the second placement surfaces 48b, the prism mirror 22 can be aligned in terms of the position in the Y direction and inclination around the Z axis. By means of the contact between the third support surfaces 28c and the third placement surfaces 48c, the prism mirror 22 can be aligned in terms of the position in the X direction. When the prism mirror 22 is assembled to the barrel body 41a, the barrel body 41a is vertically placed to have the guide projection portions 45d or the opening 410 disposed on the upper side. Thereafter, an adhesive AM is applied to appropriate portions of the first placement surfaces 48a, the second placement surfaces 48b, and the third placement surfaces 48c of the guide projection portions 45d and the prism mirror 22 is inserted like a drawer with the pair of projections 22t placed on the pair of guide projection portions 45d. The prism mirror 22 can be precisely fixed to the barrel body 41a by curing the adhesive AM of each part after the alignment has been completed. As the adhesive AM, for example, UV-curable adhesive can be used, but the adhesive AM is not limited thereto.
While the method of aligning and fixing the prism mirror 22 to the guide projection portions 45d formed on the barrel body 41a is described above, the method of fixing the first lens 21o, the second lens 21p, and the third lens 21q to the first guide projection portions 45a, the second guide projection portions 45b, and the third guide projection portions 45c is also the same as that in the case of the prism mirror 22, and the description thereof will be omitted. As for the order of assembly, first, the first lens 210 is fixed to the barrel body 41a, then the second lens 21p is fixed to the barrel body 41a, then the third lens 21q is fixed to the barrel body 41a, and finally the prism mirror 22 is fixed to the barrel body 41a.
The method of fixing the prism mirror 22 and the like to the barrel body 41a is not limited to the method using the bias described above, but may be replaced with a method using fitting or other various methods.
With reference to
A gap between the outer edge 22cp of the emitting surface 22c of the prism mirror 22 and the edge portion 44 of the opening 410 can be filled with an adhesive or a sealing material. In this case, the airtightness of the accommodation space IS can be enhanced.
In the optical unit 300, the pair of protruding portions 41f and 41g are formed on the front side of the barrel 41 so as to protrude outward in the transverse direction. A pair of attachment portions 62a and 62b are formed on an upper end 61g of the first combiner 103a so as to protrude inward. A pair of opposed 62s of the pair of attachment portions 62a and 62b are fitted to the pair of outward lateral side surfaces 51s of the barrel 41 so as to sandwich the same, whereby alignment in the ±X directions is performed so as to reduce the inclination. A pair of rear side surfaces 62t of the pair of attachment portions 62a and 62b come into contact with a pair of stepped front side surfaces 51r of the barrel 41, whereby alignment in the ±Z directions is performed so as to reduce the inclination. The plurality of protrusions 59p projecting from a bottom surfaces 59j of the pair of protruding portions 41f and 41g come into contact with a pair of upper surfaces 62j of the pair of attachment portions 62a and 62b, whereby alignment in the ±Y directions is performed. After the above-described alignment, that is, after the alignment of the six axes, an adhesive 49 is supplied between the bottom surfaces 59j of the protruding portions 41f and 41g and the and the upper surfaces 62j of the attachment portions 62a and 62b, and the supplied adhesive 49 is cured by ultraviolet rays or the like, thereby completing the fixing of the first combiner 103a to the barrel 41.
An image display device 100 according to the embodiment described above includes: the first image element 11a, the first optical member 2a disposed on a light emission side of the first image element 11a, the second optical member 2b including the incident surface 22a disposed on the light emission side of the first optical member 2a, the reflection surface 22b with which the optical axis AX is bent, and the concaved emitting surface 22c, and the barrel 41 configured to accommodate the first optical member 2a and hold the second optical member 2b, wherein the emitting surface 22c of the second optical member 2b is exposed through the opening 410 of the barrel 41, and the outer edge 22cp of the emitting surface 22c is surrounded by the edge portion 44 of the opening 41o.
In the image display device 100, the emitting surface 22c of the second optical member 2b is exposed through the opening 410 of the barrel 41, and the outer edge 22cp of the emitting surface 22c is surrounded by the edge portion 44 of the opening 41o. Thus, the emitting surface 22c of the second optical member 2b is protected by the edge portion 44 of the opening 410 of the barrel 41 and thus is less likely to be deteriorated by external force.
In the image display device 100 according to the present embodiment, the outer edge 22cp of the emitting surface 22c of the second optical member 2b is disposed to be more retracted that is more on the inner side than the edge portion 44 of the opening 410 of the barrel 41. In this case, the emitting surface 22c of the second optical member 2b is disposed deeper than the edge portion 44 of the opening 41o, whereby the emitting surface 22c of the second optical member 2b is reliably protected.
In the image display device 100 according to the present embodiment, the emitting surface 22c of the second optical member 2b is a concave surface. In this case, the emitting surface 22c of the second optical member 2b is entirely protected by the edge portion 44 of the opening 410 of the barrel 41, whereby the emitting surface 22c of the second optical member 2b is reliably protected.
Modifications and Others
Although the present disclosure has been described with reference to the above embodiments, the present disclosure is not limited to the above embodiments and can be implemented in various modes without departing from the spirit of the disclosure. For example, the following modifications are possible.
While the HMD 200 includes the first display device 100A and the second display device 100B in the above description, the HMD 200 or the image display device 100 may be configured such that one of the first display device 100A and the second display device 100B is supported in front of the eyes by the support device 100C.
While the first frame 52a and the second frame 52b are coupled to each other via the joint 50c in the above description, the first frame 52a and the second frame 52b may be directly coupled to each other, or the first frame 52a, the second frame 52b, and the joint 50c may be integrated into a metallic component.
In the description above, the image display device 100 is assumed to be mounted and used on a head, but the image display device 100 described above may also be used as a hand-held display that is not mounted on a head and is viewed into it like a pair of binoculars. In other words, the head-mounted display also includes a hand-held display in the present disclosure.
An image display device of a specific aspect includes: an image element, a first optical member disposed on a light emission side of the image element, a second optical member including an incident surface disposed on the light emission side of the first optical member, a reflection surface configured to bend an optical axis, and an emitting surface, and a barrel configured to accommodate the first optical member and hold the second optical member, wherein the emitting surface of the second optical member is exposed through an opening of the barrel, and an outer edge of the emitting surface is surrounded by an edge portion of the opening.
In the image display device described above, the emitting surface of the second optical member is exposed through the opening of the barrel, and the outer edge of the emitting surface is surrounded by the edge portion of the opening. Thus, the emitting surface of the second optical member is protected by the edge portion of the opening of the barrel and thus is less likely to be deteriorated by external force.
In the image display device of a specific aspect, the outer edge of the emitting surface of the second optical member is disposed to be more retracted that is more on the inner side than the edge portion of the opening of the barrel. In this case, the emitting surface of the second optical member is disposed deeper than the edge portion of the opening, whereby the emitting surface of the second optical member is reliably protected.
In the image display device of a specific aspect, the emitting surface of the second optical member is a concave surface. In this case, the emitting surface of the second optical member is entirely protected by the edge portion of the opening of the barrel, whereby the emitting surface of the second optical member is reliably protected.
In the image display device of a specific aspect, the barrel includes: a barrel body including two side plate members that extend substantially parallel to a plane in which the optical axis extends and spaced apart from each other, a bottom plate member that extends substantially along a plane perpendicular to the plane in which the optical axis extends and is provided with the opening, and a front plate member coupling front ends of the bottom plate member and the two side plate members, and a barrel cover that is disposed on an opposite side from the bottom plate member and covers an inner side of the barrel body to form an accommodation space. In this case, the first optical member and the second optical member can be easily disposed in the barrel having a container shape.
In the image display device of a specific aspect, the first optical member and the second optical member are aligned in the barrel body so as to be biased toward a guide projection portion projecting inward from the two side plate members. In this case, the first optical member and the second optical member can be placed on the guide projection portion to be held by the barrel body, whereby the first optical member and the second optical member can be easily aligned.
In the image display device of a specific aspect, the barrel cover covers outer side of the reflection surface of the second optical member, and the barrel cover has an inner surface extending along and in vicinity of the reflection surface. In this case, the reflection surface can be protected and prevented from coming into contact with the inner surface of the barrel cover.
The image display device of a specific aspect further includes a diaphragm plate member disposed between the first optical member and the second optical member, wherein the diaphragm plate member includes a central portion disposed in vicinity of the bottom plate member of the barrel and two side portions extending along the two side plate members from the central portion. With this configuration, even when the effective area of the second optical member is disposed in the vicinity of the outer edge on the barrel cover side, excessive light shielding by the diaphragm plate member can be prevented.
In the image display device of a specific aspect, a band-shaped portion extending along a plane perpendicular to the plane in which the optical axis extends in the barrel cover extends between end portions of the pair of side portions of the diaphragm plate member. In this case, the band-shaped portion can function as a part of the diaphragm.
The image display device of a specific aspect further includes a combiner disposed on the light emission side of the second optical member, wherein the combiner is aligned and fixed with respect to a pair of protruding portions extending on outer side of the barrel. In this case, arrangement accuracy of the combiner with respect to the barrel and the second optical member can be improved.
In the image display device of a specific aspect, the barrel is formed of polycarbonate resin.
The image display device of a specific aspect further includes a display control device configured to make the image element perform a display operation.
An optical unit according to an aspect of the present disclosure includes: an image element, a first optical member disposed on a light emission side of the image element, a second optical member including an incident surface disposed on the light emission side of the first optical member, a reflection surface configured to bend an optical axis, and an emitting surface, and a barrel configured to accommodate the first optical member and hold the second optical member, wherein the emitting surface of the second optical member is exposed through an opening of the barrel, and an outer edge of the emitting surface is surrounded by an edge portion of the opening.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2022-122356 | Jul 2022 | JP | national |
