Infinity mirror

Abstract

To provide an infinity mirror that shows an observer a pattern, displayed with images including a still image and a moving image, such that the pattern is present repeatedly in a depth direction.SOLUTION: An infinite mirror 10 comprises: a display panel 11; a half-mirror surface of an internal half-mirror 13 superposed on a display surface 12 of the display panel 11 in parallel with it; and a half-mirror surface of an external half-mirror 15 superposed on the half-mirror surface of the internal half-mirror 13 in parallel with it. The infinite mirror 10 reflects image light Im emitted from the display surface 12 repeatedly between the half-mirror surface of the half-mirror 13 and the half-mirror surface of the external half mirror 15, so that a pattern formed with the image light Im appears to be present repeatedly in a depth direction beyond the half-mirror surface of the internal half-mirror 13.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an infinity mirror. [Background technology]

[0002] Patent Document 1 discloses an infinity mirror. The infinity mirror includes a frame, a reflector attached to the rear surface of the frame, LED light-emitting elements attached to the inner surface of the frame, and a magic mirror attached to the front surface of the frame. When one looks into the infinity mirror through the magic mirror, one can see that the LED light-emitting elements are repeated infinitely in the depth direction of the infinity mirror.

[0003] Patent Document 2 discloses an optical structure consisting of a half mirror made of a first support having a half-mirror coating and a second support having a selective reflection film laminated thereon. The selective reflection film faces the half-mirror coating. A display panel is further placed opposite the back surface of the second support. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Utility Model Registration No. 3219537 [Patent Document 2] International Publication No. 2022 / 009784 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention provides an infinity mirror that allows a viewer to see a pattern displayed by an image, including still and moving images, repeating in the depth direction. [Means for solving the problem]

[0006] <1> A display panel; an internal half mirror surface superimposed on and parallel to the display surface of the display panel; an outer half mirror surface superimposed on the inner half mirror surface in parallel thereto; Equipped with By repeatedly reflecting the image light emitted from the display surface between the internal half mirror surface and the external half mirror surface, a pattern formed by the image light appears to exist repeatedly in the depth direction beyond the internal half mirror surface. Infinity mirror.

[0007] an internal half mirror having the internal half mirror surface, the internal half mirror has a transparent plate with a half-mirror coating applied to the display surface side, and a selective reflection film facing the half-mirror coating, the image light incident on the selective reflection film from the display surface is circularly polarized light, The selective reflection film transmits circularly polarized light having the same rotation direction as the image light (hereinafter referred to as F-polarized light) more efficiently than circularly polarized light having the opposite rotation direction to the image light (hereinafter referred to as R-polarized light), the reflectance of the selective reflection film for R-polarized light is higher than the reflectance of the half mirror coating for F-polarized light over the entire visible light band; the distance between the selective reflection film and the half mirror coating is narrower than the distance between the external half mirror surface and the internal half mirror surface; Infinity mirror above.

[0008] an external half mirror having the external half mirror surface, The external half mirror has a transparent plate on the internal half mirror side that is coated with a half mirror coating. Infinity mirror above.

[0009] The double-sided half mirror constituting the inner half mirror surface and the outer half mirror surface includes a transparent plate having a half mirror coating on both sides thereof, and a selective reflection film facing the half mirror coating on the display surface side; the image light incident on the selective reflection film from the display surface is circularly polarized light, The selective reflection film transmits circularly polarized light having the same rotation direction as the image light (hereinafter referred to as F-polarized light) more efficiently than circularly polarized light having the opposite rotation direction to the image light (hereinafter referred to as R-polarized light), the reflectance of the selective reflection film for R-polarized light is higher than the reflectance of the half mirror coating on the display surface side for F-polarized light over the entire visible light band; a gap between the selective reflection film and the half mirror coating on the display surface side is narrower than a gap between the external half mirror surface and the internal half mirror surface; Infinity mirror above.

[0010] the image light emitted from the display surface is linearly polarized light, A quarter-wave plate is further provided between the selective reflection film and the display surface, the fast axis or the slow axis of the quarter-wave plate is inclined at 45 degrees with respect to the azimuth angle of the linearly polarized light, The quarter-wave plate converts the image light from linearly polarized light to F-polarized light. 5. The infinity mirror according to claim 2.

[0011] the sum of the transmittance for F-polarized light incident on the internal half mirror surface from the display surface and the reflectance for R-polarized light reflected on the external half mirror surface and returning to the internal half mirror surface exceeds 100%; Infinity mirror above.

[0012] the selective reflection film is made of a liquid crystal selected from the group consisting of nematic liquid crystal and smectic liquid crystal; the liquid crystal is in a chiral phase, The phase is composed of liquid crystal molecules to which a chiral dopant has been added, or is composed of liquid crystal molecules having chirality. Infinity mirror above.

[0013] The selective reflection film is made of a cholesteric liquid crystal. Infinity mirror above.

[0014] further comprising a black bezel surrounding the display surface; the pattern is superimposed on a black background in the image; the pattern does not extend to the edge of the display surface, and the black background extends to the edge of the display surface; Infinity mirror above. [Effects of the Invention]

[0015] The present invention provides an infinity mirror that allows a viewer to see a pattern displayed by an image, including still and moving images, repeating in the depth direction. [Brief explanation of the drawings]

[0016] [Figure 1] Perspective view of an infinity mirror [Figure 2] Infinity mirror left side view [Figure 3] Infinity mirror front view [Figure 4] Left side view of the internal half mirror [Figure 5] Left side view of modified infinity mirror DETAILED DESCRIPTION OF THE INVENTION

[0017] <Infinity Mirror Overview>

[0018] FIG. 1 shows an infinity mirror 10 viewed obliquely. The infinity mirror comprises a display panel 11, an internal half mirror 13, and an external half mirror 15. The internal half mirror 13 is superimposed on a display surface 12 of the display panel 11. The external half mirror 15 is superimposed on the internal half mirror 13 and parallel to the internal half mirror 13. For ease of explanation, the side of the external half mirror 15 will be referred to as the front of the infinity mirror 10, and the side of the display panel 11 will be referred to as the back.

[0019] In one embodiment shown in FIG. 1, the display panel 11 is a flat display panel. The display panel 11 is any of a liquid crystal display, an organic electroluminescence (EL) display, a micro LED display, and other displays. The liquid crystal display has any of a twisted nematic (TN) system, an in-plane switching (IPS) system, a vertical alignment (VA) system, and other display systems. The display panel 11 preferably emits linearly polarized light or circularly polarized light. The display panel 11 may also be a display made of a polarized self-luminous device such as a laser.

[0020] The display surface 12 shown in FIG. 1 presents an image including a pattern 20 and an image including its background. The image may be a still image or a moving image. The pattern 20 may change every time a predetermined time elapses, or may disappear and reappear. The image data may be stored in the display panel 11. Alternatively, an image signal may be continuously sent from an external device to the display panel 11, and the display panel 11 may generate an image from the signal.

[0021] 2 shows the infinity mirror 10 as seen from the left side. Image light Im is emitted from a display surface 12. The infinity mirror 10 repeatedly reflects the image light Im between an internal half mirror 13 and an external half mirror 15. The structures of these half mirrors will be described later.

[0022] Figure 3 shows the infinity mirror 10 as viewed from the front. When the infinity mirror 10 is observed from the front, the pattern 20 formed by the image light appears to be repeated beyond the internal half mirror in the depth direction. The apparent repeat interval is twice the distance D1 between the internal coating 22 of the internal half mirror 13 and the external coating 17 of the external half mirror 15 shown in Figure 2.

[0023] 2, the distance D1 preferably has a value obtained by adding the thickness of the transparent plate 21 of the internal half mirror 13 to the thickness of the space between the internal half mirror 13 and the external half mirror 15, which is 0 to 100 mm. In one embodiment, the distance D1 is any one of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 30, 40, 50, 60, 70, 80, 90, and 100 mm, or a distance close thereto. In another embodiment, the thickness of the transparent plate 21 is any one of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90, and 100 mm, or a thickness close thereto.

[0024] <Half mirror configuration>

[0025] Returning to Figure 2, the external half mirror 15 is made of a transparent plate 16 with a half-mirror coating called an external coating 17 applied to the surface facing the internal half mirror 13. For example, the external coating 17 is laminated directly onto the surface of the transparent plate 16. In other embodiments, one or more other layers are interposed between the external coating 17 and the transparent plate 16. The external coating 17 forms an external half-mirror surface.

[0026] As shown in Figure 2, the internal half mirror 13 includes a transparent plate 21. A half-mirror coating called an internal coating 22 is applied to the surface of the transparent plate 21 facing the display surface 12. The internal coating 22 is laminated directly onto the surface of the transparent plate 21. In other embodiments, one or more other layers are interposed between the internal coating 22 and the transparent plate 21. The internal coating 22 forms an internal half-mirror surface. The image light Im is repeatedly reflected between the external coating 17 and the internal coating 22.

[0027] In each half mirror shown in FIG. 2, the reflectance for the repeatedly reflected image light Im is greater than or less than the transmittance, or the reflectance is equal to the transmittance. These half mirrors have a reflectance of 30% or more and less than 100% for the image light Im with a wavelength of 550 nm. In one embodiment, the reflectance is any of 35, 40, 45, 50, 52, 54, 56, 58, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 75, 80, 85, 90, and 95%. Note that in this specification, the term "half mirror" is not limited to mirrors whose transmittance and reflectance are the same or close to each other. The term "half mirror" can be replaced with the terms "magic mirror" and "beam splitter."

[0028] In one embodiment shown in Figure 2, each transparent plate has a transmittance of 20% or more and 100% or less across a wide band in the visible light spectrum, preferably across the entire visible light spectrum. In the optical materials that form the transparent plates and other optical elements, light is reflected at their interfaces. The transmittance of the optical material itself, which does not take such reflection into account, is sometimes referred to as internal transmittance. The overall transmittance, which takes into account reflection at interfaces, is sometimes referred to as external transmittance. In this specification, transmittance refers to external transmittance unless otherwise specified. The same interpretation applies to transmittance in other elements in this specification.

[0029] In one embodiment shown in FIG. 2 , the transmittance of each transparent plate is 30% or more and less than 100%. In one embodiment, the transmittance is any of 30, 40, 50, 60, 70, 80, and 90%. The transparent plates are colorless or colored. The surfaces of the transparent plates are smooth. In one embodiment, the transparent plates are made of inorganic glass. In one embodiment, the inorganic glass is soda-lime glass with a low Fe content. In one embodiment, the inorganic glass is alkali-free glass. Alkali-free glass has better rigidity than soda-lime glass. In one embodiment, the inorganic glass is laminated glass. In another embodiment, the transparent plates are made of plastic. In one embodiment, the plastic is either acrylic or polycarbonate. In another embodiment, the transparent plates are made of inorganic glass and another member. In such an embodiment, light transmits through the region made of inorganic glass. In one embodiment, the other member is plastic. In one embodiment, the plastic is acrylic, polycarbonate, or another plastic. Transparent plates 16 and 21 may be made of the same material or different materials.

[0030] 2, the transparent plate 16 is made of inorganic glass having a thickness of 0.5 to 10 mm, and in one embodiment, the thickness is any one of 1, 2, 3, 4, 5, 6, 7, 8, and 9 mm.

[0031] The outer coating 17 and inner coating 22 shown in FIG. 2 are made of partially reflective films. Partially reflective films partially transmit light. Partially reflective films partially reflect light. In one embodiment, the partially reflective film is a thin film made of a metal, metal oxide, or other dielectric. In one embodiment, the metal is aluminum. In one embodiment, the metal oxide includes either titanium oxide or niobium oxide. In one embodiment, the partially reflective film is a single layer of metal oxide. In another embodiment, the partially reflective film is a dielectric multilayer film. In one embodiment, the dielectric multilayer film includes a layer of either metal oxide or metal fluoride. The ratio of reflectance to transmittance of a single layer of metal oxide or a dielectric multilayer film is easier to adjust than other thin films.

[0032] In another embodiment shown in Figure 2, the partially reflective coating constituting the outer coating 17 and the inner coating 22 is a thin metal film. In one embodiment, a transparent protective film is formed on top of the thin metal film to protect it. In one embodiment, the transparent protective film is an organic thin film. The thickness of the thin metal film is appropriately designed according to the desired transmittance.

[0033] In one embodiment shown in FIG. 2, the partially reflective film constituting the outer coating 17 and the inner coating 22 is formed directly on the back surface of each transparent plate. In another embodiment, a thin film is formed on another transparent substrate and then attached to a support to form a partially reflective film. In one embodiment, a transparent adhesive layer is used for attachment. In one embodiment, the transparent adhesive layer is made of OCA (Optical Clear Adhesive). In one embodiment, OCA is a film-like adhesive sheet that is used to attach films together. Hereinafter, unless otherwise specified, the term "transparent adhesive layer" used elsewhere refers to the same transparent adhesive layer.

[0034] <Reducing internally reflected light returning to the display panel>

[0035] As shown in Figure 2, image light Im incident on the back surface of the inner coating 22 can become internally reflected light Rf that is reflected toward the back surface. The internally reflected light Rf enters the display panel 11 and is absorbed within the display panel 11. By reducing the internally reflected light Rf, the pattern 20 shown in Figure 3 can be made brighter. In other words, the pattern 20 that is repeated in the depth direction can be seen further into the depth.

[0036] 2 further includes a selective reflection film 23 to reduce internally reflected light Rf. In one embodiment, the internal half mirror 13 further includes a quarter-wave plate 25 between the selective reflection film 23 and the display surface 12. In one embodiment, the quarter-wave plate 25 is attached to the back surface of the selective reflection film 23 with a transparent adhesive layer.

[0037] As shown in Figure 2, the selective reflection film 23 is located closer to the display surface 12 than the internal coating 22. The selective reflection film 23 faces the internal coating 22. In one embodiment, the selective reflection film 23 is bonded to the internal coating 22 with a transparent adhesive layer. In another embodiment, the selective reflection film 23 is in close contact with the internal coating 22 but is not adhered thereto. In other words, an air layer is interposed between the selective reflection film 23 and the internal coating 22. In one embodiment, no other optical elements are inserted between the selective reflection film 23 and the internal coating 22.

[0038] Figure 4 shows the internal half mirror 13 as viewed from the left side. Image light Im is incident on the selective reflection film 23 as circularly polarized light (a). Hereinafter, circularly polarized light having the same rotation direction as the image light Im will be referred to as F-polarized light. Also, circularly polarized light having the opposite rotation direction to the image light Im will be referred to as R-polarized light. If F-polarized light is left-handed circularly polarized light, then R-polarized light will be right-handed circularly polarized light. If F-polarized light is right-handed circularly polarized light, then R-polarized light will be left-handed circularly polarized light.

[0039] The selective reflection film 23 shown in Figure 4 transmits F-polarized light better than R-polarized light over a wide band within the visible light band, preferably over the entire visible light band. Image light Im emitted from the selective reflection film 23 is incident on the internal coating 22. A portion of the image light Im remains F-polarized and passes through the internal coating 22 (b). A portion of the image light Im is reflected by the internal coating 22 and converted to R-polarized light (c). The image light Im emitted from the internal coating 22 remains R-polarized and enters the selective reflection film 23.

[0040] The selective reflection film 23 shown in Figure 4 reflects R-polarized light better than F-polarized light over a wide band within the visible light band, preferably over the entire visible light band. Most of the image light Im reflected by the internal coating 22 is reflected by the selective reflection film 23. Most of the image light Im reflected by the selective reflection film 23 is not converted to F-polarized light when reflected by the selective reflection film 23 (d). A portion of the image light Im reflected by the selective reflection film 23 remains R-polarized and transmits through the internal coating 22. A portion of the image light Im incident on the internal coating 22 is reflected again by the internal coating 22 (c).

[0041] The reflectance of the selective reflection film 23 shown in Figure 4 for R-polarized light is higher than the reflectance of the inner coating 22 for F-polarized light over the entire visible light band. The image light Im is reflected by the selective reflection film 23 and preferentially exits toward the external half mirror 15. Therefore, the internally reflected light Rf returning to the display panel 11 as shown in Figure 2 is reduced or almost eliminated. Furthermore, as a result of the reduction in internally reflected light Rf, the image light Im (F-polarized light) that passes through the internal half mirror 13 and heads toward the front of the infinity mirror 10 increases.

[0042] 4, the sum of the transmittance and reflectance of the internal half mirror 13 for the image light Im exceeds 100%. In one embodiment, the transmittance of the internal half mirror 13 for the image light Im is greater than 50%. In one embodiment, the reflectance of the internal half mirror 13 for the image light Im is greater than 50%. Here, the transmittance is the transmittance for F-polarized light that enters the internal half mirror 13 from the display surface 12. Furthermore, the reflectance is the reflectance for R-polarized light that is reflected by the external half mirror 15 and returns to the internal half mirror 13.

[0043] In one embodiment shown in Figure 4, the image light Im emitted from the display surface 12 is linearly polarized light. The fast axis or slow axis of the quarter-wave plate 25 is tilted 45 degrees with respect to the azimuth angle of the linear polarization of the image light Im. The quarter-wave plate 25 converts the image light Im from linearly polarized light to circularly polarized light. The circularly polarized light resulting from the conversion is F-polarized light.

[0044] 4, the display panel 11 is a TN liquid crystal display. In this embodiment, the polarization axis of the linearly polarized light is tilted 45 degrees relative to the vertical direction of the screen. Therefore, the fast axis of the quarter-wave plate 25 is either not tilted relative to the vertical direction of the screen, i.e., tilted 0 degrees, or tilted 90 degrees.

[0045] 4, the display panel 11 is an IPS or VA liquid crystal display. In one embodiment, the polarization axis of the linearly polarized light is not tilted with respect to the vertical direction of the screen, i.e., tilted at 0 degrees or 90 degrees. Therefore, the fast axis of the quarter-wave plate 25 is tilted at 45 degrees with respect to the vertical direction of the screen.

[0046] The return reflection between the selective reflection film 23 and the internal coating 22 shown in Fig. 4 and the repeated reflection between the internal half mirror 13 and the external half mirror 15 shown in Fig. 2 are used for different purposes. The distance D2 between the selective reflection film 23 and the internal coating 22 shown in Fig. 4 is narrower than the distance D1 between the internal half mirror 13 and the external half mirror 15. The optical path difference caused by the distance D2 is not large enough to contribute to the occurrence of repetition in the depth direction of the pattern 20 shown in Fig. 3.

[0047] <Configuration of selective reflection film>

[0048] In one embodiment shown in Figure 4, the selective reflection film 23 is made of either nematic or smectic liquid crystal. The liquid crystal is made of a phase having chirality. In one embodiment, such a phase is made of liquid crystal molecules to which a chiral dopant has been added. In another embodiment, such a phase is made of liquid crystal molecules having chirality. In one embodiment, the selective reflection film 23 is made of cholesteric liquid crystal. In another embodiment, the selective reflection film 23 is made of another liquid crystal having cholesteric regularity.

[0049] In one embodiment, cholesteric regularity refers to a state in which molecules aligned in one direction form layers, with the alignment direction slightly shifted between adjacent molecular layers, resulting in a helical structure of the molecular layers. Cholesteric regularity can also be seen in liquid crystals other than cholesteric liquid crystals. In one embodiment, to fix the cholesteric regularity, a liquid crystal phase having cholesteric regularity is fixed. In one embodiment, the selective reflection film is a polymer film obtained by curing a cholesteric liquid crystal film.

[0050] In another embodiment, the liquid crystal is a discotic liquid crystal having a helical axis. In one embodiment, a discotic liquid crystal having a helical axis is obtained by adding a chiral dopant to liquid crystal molecules of a discotic liquid crystal having no helical axis. In one embodiment, the discotic liquid crystal having a helical axis has cholesteric regularity.

[0051] The chiral dopant introduced into the liquid crystal molecules induces a twist in the liquid crystal molecules, thereby imparting optical rotation to the molecules. In one embodiment, the helical pitch of the chiral structure of the liquid crystal molecules is varied by adjusting the concentration of the chiral dopant. In another embodiment, the helical pitch is varied by changing the type of liquid crystal molecules or chiral dopant.

[0052] In one embodiment, the cholesterically ordered liquid crystal phase has a helical axis parallel to the normal to the selectively reflective film. In one embodiment, the orientation of the helical axes of all cholesterically ordered liquid crystal phases is parallel to the normal to the selectively reflective film. In one embodiment, the average orientation of the helical axes of the cholesterically ordered liquid crystal phases is parallel to the normal to the selectively reflective film.

[0053] Liquid crystals with cholesteric regularity have a specific helical structure. Such a helical structure reflects circularly polarized light that is incident from a direction parallel to the helical axis and has the same direction as the direction of rotation of the helical structure. A right-handed helical structure reflects right-handed circularly polarized light, i.e., left-handed circularly polarized light. A left-handed helical structure reflects left-handed circularly polarized light, i.e., right-handed circularly polarized light. The circularly polarized light reflected by a helical structure is the R-polarized light mentioned above. Reflecting R-polarized light is called selective reflection.

[0054] It transmits circularly polarized light that is incident from a direction parallel to its helical axis and has a direction opposite to the direction of rotation of its helical structure. A left-handed helical structure transmits right-handed circularly polarized light, i.e., left-handed circularly polarized light. A right-handed helical structure reflects left-handed circularly polarized light, i.e., right-handed circularly polarized light. The circularly polarized light transmitted by the helical structure is the F-polarized light described above. A selectively reflective film selectively reflects R-polarized light, and, conversely, selectively transmits F-polarized light. In one embodiment, the selectively reflective film transmits light other than circularly polarized light.

[0055] In selective reflection, the central wavelength λ of the reflected circularly polarized light is expressed as the product of the pitch p (μm) of the helical structure and the average refractive index n [av] of the liquid crystal in a plane perpendicular to the helical axis, as shown in the following equation (1).

[0056] λ=p×n[av] (Equation (1))

[0057] The bandwidth W of the wavelength of the reflection is expressed by the product of the birefringence anisotropy Δn of the liquid crystal and p, as shown in the following formula (2).

[0058] W=p×Δn (formula (2))

[0059] In one embodiment shown in FIG. 1, the selective reflection film 23 is a multi-layer film. In one embodiment, the selective reflection film 23 is a laminate of multiple films with different helical pitches. In one embodiment, these are laminated in order of the size of the helical pitch. The films with different helical pitches have different selective reflection bands. The bandwidth W of such a multi-layer selective reflection film is larger than that of a single-layer film. In one embodiment, the bandwidth W is broadband. In another embodiment, the bandwidth W is the entire visible light band.

[0060] In another embodiment, the selective reflection film 23 has selective reflectivity over a wide band despite being a single-layer film. This property is obtained by continuously changing the size of the helical pitch within the single-layer film. Alternatively, it is obtained by continuously changing the orientation of the helical axis within the single-layer film. In another embodiment, the selective reflection film is a laminate of multiple such single-layer films.

[0061] <Pattern and bezel>

[0062] Returning to Figure 1, pattern 20 is superimposed on a black background in the image. If the image did not include a black background and the pattern were spread across the entire image, repeated patterns would likely overlap. It would be difficult to see how the pattern repeats in the depth direction. The pattern shape and the way the black background is depicted require creative design ingenuity. The infinity mirror of this embodiment uses a display panel such as an LCD display, so the desired depiction can be achieved.

[0063] 1, the pattern 20 does not extend to the edge of the display surface 12. The black background extends to the edge of the display surface 12. In one embodiment shown in FIG. 2, the infinity mirror 10 has a bezel 14 on the display panel 11 side. The bezel 14 is provided on the back surface of the internal half mirror 13.

[0064] As shown in FIG. 3, the bezel 14 surrounds the display surface 12. In one embodiment, the front side of the bezel 14 is black. If the bezel is black and the edges of the background are black, the boundary between the bezel 14 and the display surface 12 is difficult to see. In this case, the repeated pattern 20 appears to be floating in the space within the infinity mirror 10. On the other hand, if the pattern 20 is interrupted at the edge of the display surface 12 or if the bezel 14 is a bright color, the viewer will easily recognize that the pattern 20 is an image displayed on the display panel.

[0065] <Modification> 5 is a left side view of the infinity mirror according to the modified example. The infinity mirror according to the modified example is made up of a double-sided half mirror 33. The display panel 11 and the quarter-wave plate are omitted from the drawing. The double-sided half mirror 33 repeatedly reflects the image light Im between the inner coating 22 and the outer coating 32.

[0066] As shown in FIG. 5, the double-sided half mirror 33 is made of a transparent plate 31 with an external coating 32 applied to the front surface. The external coating 32 is a half-mirror coating. The rear surface of the transparent plate 31 is applied with an internal coating 22, similar to the transparent plate 21 shown in FIG. 2. The material and optical properties of the internal coating 22 are the same as those of the internal coating 22 shown in FIG. 2. In one embodiment, the external coating 32 and the internal coating 22 are laminated directly on the surface of the transparent plate 31. In another embodiment, one or more other layers are interposed between the external coating 32 and the transparent plate 31. Furthermore, one or more other layers are interposed between the internal coating 22 and the transparent plate 31.

[0067] As shown in Figure 5, image light Im is repeatedly reflected between the outer coating 32 and the inner coating 22. In each half-mirror coating shown in Figure 5, the reflectance of the repeatedly reflected image light Im is greater than or less than the transmittance, or the reflectance is equal to the transmittance. These half-mirror coatings have a reflectance of 30% or more and less than 100% for image light Im with a wavelength of 550 nm. In one embodiment, the reflectance is any of 35, 40, 45, 50, 52, 54, 56, 58, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 75, 80, 85, 90, and 95%.

[0068] 5, the transparent plate 31 has a transmittance of 20% or more and 100% or less over a wide band in the visible light spectrum, preferably over the entire visible light spectrum. Light is reflected at the interfaces between the optical materials forming the transparent plate and other optical elements.

[0069] In one embodiment shown in FIG. 5, the transmittance of the transparent plate 31 is 30% or more and less than 100%. In one embodiment, the transmittance is any of 30, 40, 50, 60, 70, 80, and 90%. The transparent plate 31 is colorless or colored. The surface of the transparent plate 31 is smooth. In one embodiment, the transparent plate is made of inorganic glass. In one embodiment, the inorganic glass is soda-lime glass with a low Fe content. In one embodiment, the inorganic glass is alkali-free glass. Alkali-free glass has better rigidity than soda glass. In one embodiment, the inorganic glass is laminated glass. In another embodiment, the transparent plate is made of plastic. In one embodiment, the plastic is either acrylic or polycarbonate. In another embodiment, the transparent plate 31 is made of inorganic glass and another member. In such an embodiment, light transmits through the region made of inorganic glass. In one embodiment, the other member is plastic. In one embodiment, the plastic is acrylic, polycarbonate, or another plastic.

[0070] The outer coating 32 shown in FIG. 5 is made of a partially reflective film. A partially reflective film partially transmits light. A partially reflective film partially reflects light. In one embodiment, the partially reflective film is a thin film made of a metal, metal oxide, or other dielectric. In one embodiment, the metal is aluminum. In one embodiment, the metal oxide includes either titanium oxide or niobium oxide. In one embodiment, the partially reflective film is a single layer of metal oxide. In another embodiment, the partially reflective film is a dielectric multilayer film. In one embodiment, the dielectric multilayer film includes a layer of either metal oxide or metal fluoride. The ratio of reflectance to transmittance of a single layer of metal oxide or a dielectric multilayer film is easier to adjust than other thin films.

[0071] In another embodiment shown in Figure 5, the partially reflective film constituting the outer coating 32 is a thin metal film. In one embodiment, a transparent protective film is formed on top of the thin metal film to protect it. In one embodiment, the transparent protective film is an organic thin film. The thickness of the thin metal film is appropriately designed according to the desired transmittance.

[0072] In one embodiment shown in FIG. 5, the partially reflective film constituting the outer coating 32 is formed directly on the back surface of each transparent plate. In another embodiment, a thin film is formed on another transparent substrate and then attached to a support, thereby forming a partially reflective film. In one embodiment, a transparent adhesive layer is used for attachment. In one embodiment, the transparent adhesive layer is made of OCA (Optical Clear Adhesive). In one embodiment, OCA is a film-like adhesive sheet that is used to attach films together.

[0073] 5, a distance D1 is shown between the inner coat 22 and the outer coat 32. In one embodiment, the distance D1 is any one of or approximately 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 30, 40, 50, 60, 70, 80, 90, and 100 mm. In one embodiment, the distance D1 corresponds to the thickness of the transparent plate 31. In one embodiment, the thickness of the transparent plate 31 is any one of or approximately 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90, and 100 mm.

[0074] <Application> In one aspect, the infinity mirror is used as digital signage for spatial presentation. One aspect of the digital signage is a table with a top made of an infinity mirror. However, the uses of the infinity mirror of this embodiment are not limited to these. [Explanation of symbols]

[0075] 10 infinity mirror, 11 display panel, 12 display surface, 13 internal half mirror, 14 bezel, 15 external half mirror, 16 transparent plate, 17 external coating, 20 pattern, 21 transparent plate, 22 internal coating, 23 selective reflection film, 25 1 / 4 wavelength plate, D1 spacing, D2 spacing, Im image light, Rf reflected light

Claims

1. A display panel; an internal half mirror surface superimposed on and parallel to the display surface of the display panel; an outer half mirror surface superimposed on the inner half mirror surface in parallel thereto; Equipped with By repeatedly reflecting the image light emitted from the display surface between the internal half mirror surface and the external half mirror surface, a pattern formed by the image light appears to exist repeatedly in the depth direction beyond the internal half mirror surface. Infinity mirror.

2. an internal half mirror having the internal half mirror surface, the internal half mirror has a transparent plate with a half-mirror coating applied to the display surface side, and a selective reflection film facing the half-mirror coating, the image light incident on the selective reflection film from the display surface is circularly polarized light, The selective reflection film transmits circularly polarized light having the same rotation direction as the image light (hereinafter referred to as F-polarized light) more efficiently than circularly polarized light having the opposite rotation direction to the image light (hereinafter referred to as R-polarized light), the reflectance of the selective reflection film for R-polarized light is higher than the reflectance of the half mirror coating for F-polarized light over the entire visible light band; the distance between the selective reflection film and the half mirror coating is narrower than the distance between the external half mirror surface and the internal half mirror surface; The infinity mirror of claim 1 .

3. an external half mirror having the external half mirror surface, The external half mirror has a transparent plate on the internal half mirror side that is coated with a half mirror coating.

3. The infinity mirror according to claim 2.

4. The double-sided half mirror constituting the inner half mirror surface and the outer half mirror surface includes a transparent plate having a half mirror coating on both sides thereof, and a selective reflection film facing the half mirror coating on the display surface side; the image light incident on the selective reflection film from the display surface is circularly polarized light, The selective reflection film transmits circularly polarized light having the same rotation direction as the image light (hereinafter referred to as F-polarized light) more efficiently than circularly polarized light having the opposite rotation direction to the image light (hereinafter referred to as R-polarized light), the reflectance of the selective reflection film for R-polarized light is higher than the reflectance of the half mirror coating on the display surface side for F-polarized light over the entire visible light band; a gap between the selective reflection film and the half mirror coating on the display surface side is narrower than a gap between the external half mirror surface and the internal half mirror surface; The infinity mirror of claim 1 .

5. the image light emitted from the display surface is linearly polarized light, A quarter-wave plate is further provided between the selective reflection film and the display surface, the fast axis or the slow axis of the quarter-wave plate is inclined at 45 degrees with respect to the azimuth angle of the linearly polarized light, The quarter-wave plate converts the image light from linearly polarized light to F-polarized light. The infinity mirror according to any one of claims 2 to 4.

6. the sum of the transmittance for F-polarized light incident on the internal half mirror surface from the display surface and the reflectance for R-polarized light reflected on the external half mirror surface and returning to the internal half mirror surface exceeds 100%; The infinity mirror according to any one of claims 2 to 4.

7. the selective reflection film is made of a liquid crystal selected from the group consisting of nematic liquid crystal and smectic liquid crystal; the liquid crystal is in a chiral phase, The phase is composed of liquid crystal molecules to which a chiral dopant has been added, or is composed of liquid crystal molecules having chirality. The infinity mirror according to any one of claims 2 to 4.

8. The selective reflection film is made of a cholesteric liquid crystal. The infinity mirror according to any one of claims 2 to 4.

9. further comprising a black bezel surrounding the display surface; the pattern is superimposed on a black background in the image; the pattern does not extend to the edge of the display surface, and the black background extends to the edge of the display surface; The infinity mirror according to any one of claims 1 to 4.

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