JP2019207370A - Image display device - Google Patents

Abstract

To provide an image display device capable of improving the quality of a displayed image.SOLUTION: An image display device 1 includes: a half mirror 30; a display 20 for applying light L1 to one surface 30S of the half mirror 30; a retroreflective member 50 for retroreflecting light L2 reflected by the one surface 30S of the half mirror 30 or light transmitted by the half mirror 30; and a lens 40 provided on an optical path of light L3 which has been reflected by the retroreflective member 50, so as to return to the half mirror 30.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an image display device, and more particularly to an image display device including a retroreflective member.

  As an image display device that can visually recognize a three-dimensional image without using dedicated glasses, an image display device including a display that emits light constituting the image, a half mirror, and a retroreflective member is widely known.

  For example, Patent Document 1 below describes an imaging device that is an example of an image display device. This imaging apparatus includes a display, a retroreflective member, and a polarizing filter that functions as a half mirror. In this imaging apparatus, the light emitted from the display is reflected by one surface of the polarizing filter, then retroreflected by the retroreflective member, returns to the polarizing filter again, passes through the polarizing filter, and the other surface of the polarizing filter. It is imaged in the air in the side.

  Patent Document 2 below describes an aerial display device that is an example of an image display device. This aerial display device is an image display device having a convex lens disposed in front of the display. In this aerial display device, a convex lens arranged in front of the display enlarges an image displayed on the display. The light that forms the enlarged image is reflected by one surface of the half mirror, then retroreflected by the retroreflective member, and then returns to the half mirror again and is half-similar to the imaging device disclosed in Patent Document 1. The light passes through the mirror and is imaged in the air on the other side of the half mirror.

JP 2011-253128 A JP 2018-31925 A

  However, in the image display device using the retroreflective member as described in Patent Document 1, a part of the light retroreflected by the retroreflective member may be diffused to blur the outline of the image displayed in the air. is there. Further, when an image displayed on the display is enlarged by a lens and then retroreflected by a retroreflective member as in the aerial display device of Patent Document 2, the image displayed in the air is more easily blurred and unclear.

  SUMMARY An advantage of some aspects of the invention is that it provides an image display device capable of improving the quality of an image to be displayed.

  The image display device of the present invention for solving the above-described problems includes a half mirror, a display for irradiating light on one surface of the half mirror, and light reflected on the one surface of the half mirror or the half mirror. A retroreflective member that retroreflects the light that passes through the lens, and a lens that is disposed on the optical path of the light that is reflected by the retroreflective member and returns to the half mirror.

  The light retroreflected by the retroreflective member may diffuse as described above. Even when a retroreflective member that easily diffuses the retroreflected light is used, the lens disposed between the retroreflective member and the half mirror is a converging lens such as a convex lens. The light retroreflected by the reflecting member is transmitted through the lens, so that the diffusion of the light is suppressed. Therefore, blurring of the outline of the image displayed by the image display device can be suppressed. That is, the image display device of the present invention can improve the quality of the displayed image.

  On the other hand, when the lens disposed between the retroreflective member and the half mirror is a diverging lens such as a concave lens, light traveling from the half mirror toward the retroreflective member is diverged by passing through the lens. Therefore, the irradiation range of the retroreflective member for the light is expanded as compared with the case where the image display device does not include a lens. Therefore, light can be irradiated to many retroreflective elements as compared with the case where the image display device does not include a lens. Therefore, when some retroreflective elements have a defect in the retroreflective member, the influence due to the defect can be suppressed. That is, when a retroreflective member having a defect in a part of the retroreflective element is used, the lens disposed between the retroreflective member and the half mirror is a divergent lens such as a concave lens. The influence by is suppressed. As a result, the image display device of the present invention can improve the quality of the displayed image.

  The retroreflective member retroreflects the light reflected by the one surface of the half mirror, and the lens is reflected from the retroreflective member on the optical path of the light returning to the half mirror and from the display. It is preferable to be disposed over the optical path of the light toward the half mirror.

  By arranging the lens on the optical path of the light from the display toward the half mirror, the image displayed on the display can be enlarged. Therefore, the image display device can enlarge an image to be displayed.

  Moreover, it is preferable that the retroreflective element of the retroreflective member is smaller than the pixel of the display.

  The retroreflective member has a plurality of retroreflective elements that retroreflect light. Since the retroreflective element is smaller than the display pixel, light emitted from one pixel of the display is easily retroreflected by the plurality of retroreflective elements. Therefore, the image display device can display a high-definition image.

  The lens is preferably a converging lens.

  Since the lens disposed between the retroreflective member and the half mirror is a convergent lens, the image display apparatus can improve the quality of the displayed image as described above.

  It is also preferable that the lens is a diverging lens.

  Since the lens disposed between the retroreflective member and the half mirror is a diverging lens, the image display apparatus can improve the quality of the displayed image as described above.

  As described above, according to the present invention, it is possible to provide an image display device capable of improving the quality of an image to be displayed.

It is a figure which shows roughly the cross section of the image display apparatus concerning 1st Embodiment of this invention. It is a figure which shows roughly the cross section of the image display apparatus concerning 2nd Embodiment of this invention. It is a figure which shows schematically the cross section of the image display apparatus concerning 3rd Embodiment of this invention.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a preferred embodiment of an image display device according to the invention will be described in detail with reference to the drawings.

(First embodiment)
FIG. 1 is a diagram schematically showing a cross section of an image display apparatus according to a first embodiment of the present invention. As shown in FIG. 1, the image display apparatus 1 according to the present embodiment includes a housing 10, a display 20, a half mirror 30, a lens 40, and a retroreflective member 50 as main components.

  The housing 10 of this embodiment is configured in a box shape having one opening by a bottom wall 11 and a frame wall 12 surrounding the outer periphery of the bottom wall 11. The opening is closed by a plate-like half mirror 30. That is, one opening of the cylinder formed by the frame wall 12 is closed by the bottom wall 11, and the other opening is closed by the plate-like half mirror 30. The display 20, the lens 40, and the retroreflective member 50 are accommodated in a space surrounded by the housing 10 and the half mirror 30.

  The display 20 of this embodiment is attached to the housing 10 via the first base plate 13. More specifically, the display 20 is fixed to the first pedestal plate 13, and the first pedestal plate 13 is connected to the bottom wall 11 and the frame wall 12 of the housing 10 so that the display 20 has a predetermined shape. Fixed in posture. The display 20 and the first base plate 13 are fixed to each other by, for example, an adhesive or a screw. The first base plate 13 may be fixed to the housing 10 with, for example, an adhesive or a screw, or may be formed integrally with the housing 10.

  In addition, the display 20 has a display surface 20S that emits light L1 constituting the image F1. In FIG. 1, an image F1 displayed on the display 20 is virtually indicated by a broken line. The display 20 is arranged such that light L1 emitted in a direction substantially perpendicular to the display surface 20S is incident obliquely on one surface 30S that is the surface of the half mirror 30 on the display 20 side. That is, the display 20 and the half mirror 30 are arranged so that the display surface 20S of the display 20 and the one surface 30S of the half mirror 30 are non-vertical and non-parallel.

  Such a display 20 is not particularly limited as long as it is an image output device that displays an image F1 having a predetermined brightness. For example, a liquid crystal display, a liquid crystal projector, an LED (Light Emitting Diode) display, an OLED (Organic Light Emitting Diode) display, a plasma display, a laser display, a CRT (Cathode Ray Tube), or the like can be used as the display 20. Moreover, as a light source with which the display 20 is provided, an incandescent lamp, a fluorescent lamp, a high-intensity discharge lamp (HID), LED, OLED, various lasers etc. are mentioned, for example.

  The display 20 may be configured by a plurality of image output devices. The image output from the display 20 may be a still image or a moving image.

  The half mirror 30 of the present embodiment is a plate-like member that reflects at least a part of L1 emitted from the display 20 by the surface 30S on the display 20 side. The ratio of light transmittance and reflectance (transmittance / reflectance) of the half mirror 30 can be, for example, 95/5 to 5/95, and can be in the range of 80/20 to 20/80. preferable.

  Such a half mirror 30 is, for example, a film in which a reflective film is coated on one side of a white plate such as transparent resin or glass, or a glass or film in which a thin metal layer is formed on one side by vapor deposition or sputtering, a wire It is composed of a grid polarizer, a reflective polarizer, a beam splitter, and the like.

  When the half mirror 30 is formed by depositing aluminum on the surface of the glass plate so as to have a thickness of about 50 nm to about 80 nm, both the specular reflectance and light transmittance of the half mirror 30 may be about 50%. it can.

  When the half mirror 30 is a reflective polarizing plate, the half mirror 30 reflects light having a predetermined polarization direction and transmits light having a polarization direction substantially perpendicular to the polarization direction of the light. In the case where the half mirror 30 of the present embodiment is a reflective polarizing plate, when the light emitted from the display 20 is polarized, the half mirror 30 reflects the polarized light and is approximately perpendicular to the polarization direction of the polarized light. It arrange | positions so that the light of a polarization direction may be permeate | transmitted. Examples of the reflective polarizing plate used as the half mirror 30 include a reflective polarizing plate composed of a multilayer laminate represented by 3M trade names DBEF and APF, and a trade name WGFTM manufactured by Asahi Kasei E-Materials. A reflective polarizing plate provided with a representative wire grid polarizer can be used. Moreover, as a reflective polarizing plate used as the half mirror 30, a film made of polyvinyl alcohol dyed with iodine, a protective film made of triacetyl cellulose, etc. are laminated on both sides or one side of the film made of polyvinyl alcohol dyed with iodine. Examples include a laminate of a reflective polarizing plate composed of the above multilayer laminate on an absorption polarizing plate. In this case, the reflective polarizing plate composed of the multilayer laminate is located closer to the display 20 than the absorption polarizing plate, and the transmission axis of the reflective polarizing plate composed of the multilayer laminate is the absorption polarizing plate. It arrange | positions so that it may become substantially parallel to a transmission axis.

  The lens 40 of the present embodiment is arranged over the optical path where the light L1 emitted from the display 20 goes to the half mirror 30 and the optical path where the light L2 reflected by the half mirror 30 goes to the retroreflective member 50. . Since the retroreflective member 50 retroreflects incident light in a direction substantially opposite to the incident direction of the light, the arrangement of the lens 40 is the light L3 reflected by the retroreflective member 50 and returning to the half mirror 30. It is also on the street. In other words, the lens 40 of the present embodiment is disposed across the optical path of the light L3 that is reflected by the retroreflective member 50 and returns to the half mirror 30, and the optical path of the light L1 that travels from the display 20 to the half mirror 30.

  Further, the lens 40 of the present embodiment is a converging lens. Examples of the converging lens include a convex lens such as a biconvex lens, a plano-convex lens, and a convex meniscus lens, a Fresnel lens, a micro lens, and a cylindrical lens.

  Further, the position and orientation of the lens 40 of the present embodiment are defined so that the image F2 displayed by the image display device 1 is an enlarged image than the image F1 displayed by the display 20. In FIG. 1, an image F2 displayed by the image display device 1 is virtually indicated by a broken line. For example, the size of the image F <b> 2 can be adjusted by adjusting the distance between the lens 40 and the half mirror 30 and the distance between the lens 40 and the display 20.

  The retroreflective member 50 of this embodiment is attached to the housing 10 via the second pedestal plate 14. More specifically, the retroreflective member 50 is fixed to the second pedestal plate 14 and the second pedestal plate 14 is connected to the bottom wall 11 and the frame wall 12 of the housing 10 in a bracing manner, whereby the retroreflective member. 50 is fixed in a predetermined posture. The retroreflective member 50 and the second base plate 14 are fixed to each other by, for example, an adhesive or a screw. The second base plate 14 may be fixed to the housing 10 with, for example, an adhesive or a screw, or may be formed integrally with the housing 10. In addition, the 2nd base plate 14 may have a curved surface, and the retroreflection member 50 may be arrange | positioned along the curved surface.

  Further, the retroreflective member 50 of the present embodiment includes a plurality of retroreflective elements formed on the surface of the base material layer 51 and the base material layer 51 opposite to the side on which the light reflected by the half mirror 30 is incident. 52. However, the plurality of retroreflective elements 52 may be formed on both surfaces of the base material layer 51. The plurality of retroreflective elements 52 are preferably formed without gaps on one or both surfaces of the base material layer 51.

  The retroreflective element 52 is preferably formed integrally with the base material layer 51. That is, it is preferable that the base material layer 51 and the retroreflective element 52 are composed of the same composition, and the retroreflective member 50 is a single layer. If the retroreflective member 50 is a single layer, when the light L2 is incident on the retroreflective element 52, light loss due to reflection between layers that may occur when the retroreflective member 50 is a multilayer, image shift Since no blur or distortion occurs, the image display device 1 can display a clear image F2. In addition, when the retroreflective member 50 is a single layer, there is no peeling between layers due to the influence of heat or the like, which may occur when the retroreflective member 50 is a multilayer, and bubbles are not generated between the layers, and the image display device 1 is clear. The image F2 can be displayed.

  The retroreflective element 52 is a prism type retroreflective element such as a linear prism element, a cross prism element, a triangular pyramid type retroreflective element, a full cube corner type retroreflective element, a tent type retroreflective element, and a conical type retroreflective element. is there. However, the retroreflective element 52 is preferably a triangular pyramid retroreflective element or a full cube corner retroreflective element. The triangular-pyramidal retroreflective element has three triangular reflecting surfaces that are substantially perpendicular to each other. These reflecting surfaces share one vertex and adjacent reflecting surfaces share one side. Yes. A full cube corner retroreflective element has three rectangular reflecting surfaces that are substantially perpendicular to each other. These reflecting surfaces share one vertex and adjacent reflecting surfaces share one side. ing. When the retroreflective element 52 is a triangular pyramid type retroreflective element or a full cube corner type retroreflective element, it is easy to accurately manufacture a mold used when the retroreflective element 52 is manufactured.

  As the prism type retroreflective element, an internal total reflection type retroreflective element and a specular reflection type retroreflective element are known. When the retroreflective element 52 is an internal total reflection type retroreflective element, the retroreflective element 52 is preferably made of a transparent material and disposed so as to be in contact with air. Due to the difference in refractive index between the transparent material and air, the light incident on the reflection surface of the retroreflective element 52 at an angle exceeding the critical angle is totally internally reflected. More specifically, the light incident on the retroreflective element 52 at an angle within a predetermined range undergoes total internal reflection three times in total by sequentially total internal reflection on each of the three reflecting surfaces of the retroreflective element 52, Retroreflected. In the case where the retroreflective element 52 is an internal total reflection type retroreflective element, the reflectance at the three reflecting surfaces of the retroreflective element 52 can be 99% or more. In general, the internal total reflection type retroreflective element exhibits higher retroreflection performance than the specular reflection type retroreflective element. Therefore, when the retroreflective element 52 is an internal total reflection type retroreflective element, the image display apparatus 1 can easily display a bright image F2.

  By the way, the image F2 displayed by the image display device 1 is composed of light of various wavelengths. When the retroreflective element 52 is an internal total reflection type retroreflective element as described above, the critical angle of the reflective surface of the retroreflective element 52 depends on the wavelength of light incident on the reflective surface. Therefore, when the retroreflective element 52 is an internal total reflection type retroreflective element, light of some wavelengths may not be retroreflected by the retroreflective element 52. On the other hand, when the retroreflective element 52 is a specular reflection type retroreflective element, the retroreflective element 52 can retroreflect light regardless of the wavelength of light incident on the reflective surface. The reflective surface of the specular reflection type retroreflective element is formed by a specular reflection layer made of metal such as aluminum or silver. Such a specular reflection layer is provided by evaporating or sputtering a metal on the surface of the prism type retroreflective element. The thickness of the specular reflection layer is not particularly limited as long as it can sufficiently reflect light, but is 80 nm or more and 200 nm or less, for example. In the case where the retroreflective element 52 is a specular reflection type retroreflective element, the light incident on the retroreflective element 52 is specularly reflected by the respective specular reflection layers in order to be specularly reflected three times and retroreflected. When the retroreflective element 52 is a specular reflection type retroreflective element, the reflectivity at the three reflective surfaces of the retroreflective element 52 can be set to about 90%. When the retroreflective element 52 is a specular reflection type retroreflective element, as described above, the retroreflective element 52 retroreflects the light regardless of the wavelength of the light incident on the reflective surface, thereby forming the light L3 constituting the image F2. Is considered to be easy to form an image.

  The area of the retroreflective element 52 when the retroreflective member 50 is viewed in plan is preferably smaller than the area of the pixels of the display 20. Since the retroreflective element 52 is smaller than the pixels of the display 20, light emitted from one pixel of the display 20 is easily retroreflected by the plurality of retroreflective elements 52. Therefore, the image display device 1 can display a high-definition image F2. The length of one side of the retroreflective element 52 when the retroreflective member 50 is viewed in plan is, for example, 10 μm to 300 μm, preferably 10 μm to 250 μm.

  Next, imaging of the image F2 by the image display device 1 will be described.

  As shown in FIG. 1, the light L <b> 1 emitted from the display 20 passes through the lens 40 and reaches the half mirror 30. Then, at least a part of the light L1 reaching the half mirror 30 is reflected by the surface 30S of the half mirror 30 on the display 20 side. At least a part of the light L2 reflected by the half mirror 30 passes through the lens 40 and reaches the retroreflective member 50, and is retroreflected by the retroreflective member 50 as described above. The light L3 retroreflected by the retroreflective member 50 passes through the lens 40 again and reaches the half mirror 30. Then, at least a part of the light L3 that reaches the half mirror 30 again passes through the half mirror 30. As a result, the image F2 is formed in the air on the surface side opposite to the surface 30S on the display 20 side of the half mirror 30.

  As described above, the image display device 1 according to the present embodiment includes the half mirror 30, the display 20 that irradiates light on one surface 30S of the half mirror 30, and the light that is reflected by the one surface 30S of the half mirror 30. And a lens 40 disposed on the optical path of the light reflected by the retroreflective member 50 and returning to the half mirror 30.

  As described above, the light L3 retroreflected by the retroreflective member 50 may diffuse. Even when the retroreflective member 50 that easily diffuses the retroreflected light is used, the lens 40 disposed between the retroreflective member 50 and the half mirror 30 is a convex lens as in the present embodiment. And the like, the light L3 retroreflected by the retroreflective member 50 is transmitted through the lens 40, so that the diffusion of the light L3 is suppressed. Therefore, blurring of the outline of the image F2 displayed by the image display device 1 can be suppressed. That is, the image display device 1 can improve the quality of the image F2 to be displayed.

  Further, in the image display device 1 of the present embodiment, the lens 40 is disposed on the optical path of light from the display 20 toward the half mirror 30. By arranging the lens 40 on the optical path of the light from the display 20 toward the half mirror 30, the image F1 displayed on the display 20 can be enlarged by the lens 40. Therefore, the image display device 1 can display the image F2 in which the blurring of the outline is suppressed while the image F1 is enlarged.

(Second Embodiment)
Next, a second embodiment of the present invention will be described in detail with reference to FIG. In addition, about the component which is the same as that of 1st Embodiment, or the equivalent, unless otherwise demonstrated, the same referential mark is attached | subjected and the overlapping description is abbreviate | omitted.

  FIG. 2 is a diagram schematically showing a cross section of an image display apparatus according to the second embodiment of the present invention. As shown in FIG. 2, the image display device 2 of the present embodiment is different from the image display device 1 of the first embodiment in that the lens 40 is not arranged on the optical path of light from the display 20 toward the half mirror 30. Mainly different.

  An image F2 by the image display device 2 is formed as follows.

  As shown in FIG. 2, the light L <b> 1 emitted from the display 20 reaches the half mirror 30 without passing through the lens 40. Then, at least a part of the light L1 reaching the half mirror 30 is reflected by the surface 30S of the half mirror 30 on the display 20 side. At least a part of the light L2 reflected by the half mirror 30 passes through the lens 40 and reaches the retroreflective member 50, and is retroreflected by the retroreflective member 50 as described above. The light L3 retroreflected by the retroreflective member 50 passes through the lens 40 again and reaches the half mirror 30. At this time, diffusion of the light L3 transmitted through the lens 40 is suppressed. Then, at least a part of the light L3 that reaches the half mirror 30 again passes through the half mirror 30. As a result, the image F2 is formed in the air on the surface side opposite to the surface 30S on the display 20 side of the half mirror 30.

(Third embodiment)
Next, a third embodiment of the present invention will be described in detail with reference to FIG. In addition, about the component which is the same as that of 2nd Embodiment, or equivalent, except the case where it demonstrates especially, the same referential mark is attached | subjected and the overlapping description is abbreviate | omitted.

  FIG. 3 is a diagram schematically showing a cross section of an image display apparatus according to the third embodiment of the present invention. As shown in FIG. 3, the image display device 3 according to the present embodiment is different from the image display device according to the second embodiment in that the display 20 and the retroreflective member 50 are arranged on opposite sides of the half mirror 30. Mainly different from 2. In addition, the display 20 of the present embodiment is disposed along the frame wall 12, and the half mirror 30 is inclined with respect to the display surface 20 </ b> S of the display 20. The retroreflective member 50 is inclined with respect to the display surface 20 </ b> S of the display 20 and is disposed at a predetermined angle with respect to the half mirror 30.

  The image F2 by the image display device 3 is formed as follows.

  As shown in FIG. 3, at least a part of the light L <b> 1 emitted from the display 20 passes through the half mirror 30 and the lens 40 and reaches the retroreflective member 50. At least part of the light L1 that has reached the retroreflective member 50 is retroreflected by the retroreflective element 52. The light L4 retroreflected by the retroreflective element 52 passes through the lens 40 again and reaches the half mirror 30, and at least a part of the light L4 reaching the half mirror 30 is reflected by the half mirror 30. Thus, the light L5 reflected by the half mirror 30 forms an image to form an image F2.

  As mentioned above, although the said embodiment was demonstrated to the example about this invention, this invention is not limited to these.

  For example, the lens 40 may be a diverging lens such as a concave lens. When the lens 40 disposed between the retroreflective member 50 and the half mirror 30 is a diverging lens, the light L2 from the half mirror 30 toward the retroreflective member 50 is diverged by passing through the lens 40. Therefore, the irradiation range of the light L2 on the retroreflective member 50 is expanded as compared with the case where the image display device does not include the lens 40. Therefore, more retroreflective elements 52 can be irradiated with light than when the image display device does not include the lens 40. Therefore, even if some retroreflective elements 52 have a defect in the retroreflective member 50, the influence of the defect can be suppressed. That is, when the retroreflective member 50 having a defect in some of the retroreflective elements 52 is used, the lens 40 disposed between the retroreflective member 50 and the half mirror 30 is a divergent lens such as a concave lens. The influence by the malfunction of the retroreflection element 52 is suppressed. As a result, the image display device of the present invention can improve the quality of the displayed image.

  In the image display device of the present invention, configurations other than the display 20, the half mirror 30, the lens 40, and the retroreflective member 50 may be provided in the housing 10. For example, a phase difference member (¼λ plate) may be provided on the surface of the retroreflective member 50 on the light incident side. When a reflective polarizing plate is used as the half mirror 30, by providing a phase difference member on the incident surface side of the retroreflective member 50, the image display device improves the utilization efficiency of light emitted from the display 20, and the image F2 is displayed. It can display brighter. In addition, as said retardation member, the F film by the Gunze company whose base material is a cycloolefin polymer is marketed, for example.

  As described above, according to the present invention, an image display device capable of improving image quality is provided, and the image display device of the present invention is suitable for various signboards, information display devices, information input devices, and amusement devices, for example. Used.

1, 2, 3 ... Image display device 10 ... Housing 20 ... Display 30 ... Half mirror 40 ... Lens 50 ... Retroreflective member 52 ... Retroreflective element

Claims (5)

Half mirror,
A display that emits light to one surface of the half mirror;
A retroreflective member that retroreflects light reflected by the one surface of the half mirror or light transmitted through the half mirror;
A lens disposed on the optical path of the light reflected by the retroreflective member and returning to the half mirror;
An image display device comprising: The retroreflective member retroreflects the light reflected by the one surface of the half mirror,
2. The lens according to claim 1, wherein the lens is disposed across an optical path of light reflected by the retroreflective member and returning to the half mirror and an optical path of light traveling from the display toward the half mirror. The image display device described. The image display apparatus according to claim 1, wherein a retroreflective element of the retroreflective member is smaller than a pixel of the display. The image display apparatus according to claim 1, wherein the lens is a converging lens. The image display apparatus according to claim 1, wherein the lens is a diverging lens.

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