Floating Image Display Device

Abstract

This improves the sense of floating and resolution of floating images displayed by the floating image display device. [Solution] The floating image display device 1 of the present disclosure comprises a display unit 2, an optical system 3 that forms an image of the image light L emitted from the display unit 2 as a floating image F of a real image, and a cover member 4 located between the optical system 3 and the imaging position 12 of the floating image F. The cover member 4 has a light-shielding portion 61 that shields a part of the image light L and a plurality of light-transmitting portions 62 that transmit another part of the image light L. At least one of the plurality of light-transmitting portions 62 has a shape with multiple sides.

Description

[Technical Field]

[0001] This disclosure relates to a floating image display device. [Background technology]

[0002] Conventionally, various devices have been proposed for forming an image in the air using image light. For example, Patent Document 1 discloses an aerial imaging device comprising an image light emission device, an imaging element for forming an image in the air using image light emitted from the image light emission device, and a decorative sheet for making the image light emission device and the imaging element difficult to observe from the outside. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-76811 [Overview of the project] [Problems that the invention aims to solve]

[0004] Conventional aerial imaging devices have room for improvement in terms of enhancing the sense of floating and resolution of the images projected into the air. [Means for solving the problem]

[0005] The floating image display device of this disclosure comprises a display unit and An optical system that forms an image of a floating real image from the image light emitted from the display unit, The optical system and the imaging position of the floating image are provided, The cover member has a light-shielding portion that blocks a portion of the image light and a plurality of light-transmitting portions that transmit another portion of the image light, and at least one of the plurality of light-transmitting portions has a shape with multiple sides.

[0006] Furthermore, the floating image display device of this disclosure includes a display unit and An optical system that forms an image of the image light emitted from the display unit as a real floating image, A reflective polarizing plate positioned between the optical system and the imaging position of the floating image, The reflective polarizing plate transmits polarized light having a polarization axis in a first direction and reflects polarized light having a polarization axis in a second direction orthogonal to the first direction.

Advantages of the Invention

[0007] According to the present disclosure, the resolution and floating feeling of the floating image can be improved.

Brief Description of the Drawings

[0008] [Figure 1] It is a cross-sectional view showing an example of a floating image display device of the first embodiment. [Figure 2] It is a cross-sectional view showing another example of the floating image display device of the first embodiment. [Figure 3] It is a cross-sectional view showing the configuration of a cover member. [Figure 4] It is a diagram showing an excerpt of a part of a decorative film viewed in the depth direction. [Figure 5] It is a diagram showing an excerpt of a part of a decorative film viewed in the depth direction. [Figure 6] It is a diagram showing an excerpt of a part of a decorative film viewed in the depth direction. [Figure 7] It is a diagram showing an excerpt of a part of a decorative film viewed in the depth direction. [Figure 8] It is a cross-sectional view showing the configuration of a cover member. [Figure 9] It is a diagram showing an example of a light-transmitting part viewed in the depth direction. [Figure 10] It is a graph showing the relationship between the modulation transfer function and the spatial frequency of the image light transmitted through the light-transmitting part of FIG. 9. [Figure 11] It is a diagram showing an example of a light-transmitting part viewed in the depth direction. [Figure 12] It is a graph showing the relationship between the modulation transfer function and the spatial frequency of the image light transmitted through the light-transmitting part of FIG. 11. [Figure 13]It is a diagram showing an enlarged view of a part of the display surface that the user views through the optical system. [Figure 14] It is a diagram showing an excerpt of a part of the decorative film viewed in the depth direction. [Figure 15] It is a diagram showing an excerpt of a part of the decorative film viewed in the depth direction. [Figure 16] It is a diagram showing an example of the decorative film viewed in the depth direction. [Figure 17] It is a cross-sectional view showing the configuration of the cover member. [Figure 18] It is a cross-sectional view showing the configuration of the cover member. [Figure 19] It is a cross-sectional view showing the configuration of the cover member. [Figure 20] It is a cross-sectional view showing the configuration of the cover member. [Figure 21] It is a cross-sectional view showing the configuration of the cover member. [Figure 22] It is a cross-sectional view showing the configuration of the cover member. [Figure 23] It is a cross-sectional view showing the main configuration of the floating image display device of the second embodiment. [Figure 24] It is a cross-sectional view showing the configuration of the cover member and the reflective polarizing plate. [Figure 25] It is a cross-sectional view showing the configuration of the cover member and the reflective polarizing plate. [Figure 26] It is a cross-sectional view showing the configuration of the cover member and the reflective polarizing plate.

Embodiments for Carrying Out the Invention

[0009] Embodiments of this disclosure will be described below with reference to the drawings. The figures referenced below show the main components of the floating image display device according to the embodiment. The floating image display device according to the embodiment may include well-known components such as a display unit holding member and an optical system holding member, which are not shown. The figures referenced below are schematic, and the dimensional ratios etc. on the drawings do not necessarily correspond to those in reality. In this specification, in some drawings, a Cartesian coordinate system XYZ is defined for convenience. The X-axis direction is also referred to as the first direction. The Y-axis direction is also referred to as the second direction. The Z-axis direction is also referred to as the third direction or depth direction. In the description of the embodiments below, the positive direction of the Y-axis direction is considered upward, and terms such as upper end and lower end may be used. The second direction may be the vertical direction (i.e., the direction of gravity), but is not limited to the vertical direction, and may be a direction intersecting the vertical direction. The first direction may be the horizontal direction (a direction perpendicular to the vertical direction), but is not limited to the horizontal direction, and may be a direction intersecting the horizontal direction.

[0010] Figure 1 is a cross-sectional view showing an example of a floating image display device according to the first embodiment, and Figure 2 is a cross-sectional view showing another example of a floating image display device according to the first embodiment. Figure 3 is a cross-sectional view showing the configuration of the decorative film of the cover member, Figures 4 to 7 are diagrams showing excerpts of the decorative film as viewed in the depth direction, and Figure 8 is a cross-sectional view showing the configuration of the decorative film of the cover member. Figure 9 is a diagram showing an example of a light-transmitting portion as viewed in the depth direction, Figure 10 is a graph showing the relationship between the modulation transfer function of the image light transmitted through the light-transmitting portion of Figure 9 and the spatial frequency, Figure 11 is a diagram showing an example of a light-transmitting portion as viewed in the depth direction, and Figure 12 is a graph showing the relationship between the modulation transfer function of the image light transmitted through the light-transmitting portion of Figure 11 and the spatial frequency. Figure 13 is a diagram showing an enlarged view of a part of the display surface that the user sees through the optical system, Figures 14 and 15 are diagrams showing excerpts of the decorative film as viewed in the depth direction, Figure 16 is a diagram showing an example of the decorative film as viewed in the depth direction, and Figures 17 to 22 are cross-sectional views showing the configuration of the cover member. In Figures 4-7, 9, 11, and 14-16, hatching is added to the light-shielding areas to facilitate illustration.

[0011] The floating image display device 1 of the first embodiment comprises a display unit 2, an optical system 3, and a cover member 4, as shown in Figure 1. The floating image display device 1 displays a floating image F, which is a real image, in the air within the user's 5 field of view.

[0012] The display unit 2 has a display surface 2a and displays an image formed on the display surface 2a as a floating image F. In other words, the display unit 2 emits image light L, which is formed as a floating image F, from the display surface 2a.

[0013] The display unit 2 includes multiple pixels. The multiple pixels are arranged in a matrix and partitioned from each other by a grid-like black matrix. Each of the multiple pixels includes multiple subpixels. Each of the multiple subpixels may correspond to one of the colors R (red), G (green), and B (blue).

[0014] The display unit 2 may be composed of a transmissive display device. The transmissive display device may be a liquid crystal display device including a backlight and a liquid crystal panel. The backlight may be a direct-lit backlight having a plurality of light sources arranged two-dimensionally on the back side of the liquid crystal panel. The backlight may also be an edge-lit backlight having a plurality of light sources arranged on the outer edge of the liquid crystal panel. The edge-lit backlight may have a lens array, a light guide plate, a diffuser plate, etc., for uniformly illuminating the liquid crystal panel. The light source of the backlight may be, for example, a light-emitting diode (LED) element, a semiconductor laser (LD) element, a cold cathode fluorescent lamp, a halogen lamp, a xenon lamp, etc.

[0015] The liquid crystal panel may be any known liquid crystal panel. Known liquid crystal panels may be, for example, IPS (In-Plane Switching), FFS (Fringe Field Switching), VA (Vertical Alignment), or ECB (Electrically Controlled Birefringence) liquid crystal panels.

[0016] Transmissive display devices are not limited to liquid crystal displays; they may also be MEMS (Micro Electro Mechanical Systems) shutter-type display devices.

[0017] The display unit 2 is not limited to a transmissive display device, but may be composed of a self-emissive display device. A self-emissive display device has a plurality of light-emitting elements arranged in two dimensions. The light-emitting elements may be, for example, LED elements, organic electroluminescence (OEL) elements, organic light-emitting diode (OLED) elements, LD elements, etc.

[0018] The optical system 3 images the image light L emitted from the display unit 2 into a floating image F of the real image in the air. The optical system 3 images the image light L at an imaging position 12 within a virtual imaging plane 11. The optical system 3 may have a first concave mirror 31 and a second concave mirror 32, as shown in Figure 1.

[0019] The first concave mirror 31 has a concave first reflective surface 31a. The first concave mirror 31 reflects the image light L emitted from the display unit 2 in a direction different from the direction toward the display unit 2.

[0020] The second concave mirror 32 has a concave second reflective surface 32a. The second concave mirror 32 reflects the image light L reflected by the first concave mirror 31 in a direction different from the direction toward the first concave mirror 31, and forms an image as a floating image F of the real image.

[0021] The optical system 3 is not limited to the configuration shown in Figure 1. The optical system 3 may have a first concave mirror 31, a second concave mirror 32, and a convex mirror 33, as shown in Figure 2.

[0022] The convex mirror 33 has a convex third reflective surface 33a. The convex mirror 33 is located in the optical path of the image light L between the first concave mirror 31 and the second concave mirror 32. The convex mirror 33 reflects the image light L reflected by the first concave mirror 31 toward the second concave mirror 32. The second concave mirror 32 reflects the image light L reflected by the convex mirror 33 toward a direction different from the direction toward the convex mirror 33, forming a floating image F of the real image.

[0023] The first concave mirror 31 may be a free-form concave mirror in which the first reflective surface 31a is defined by a free-form surface. The second concave mirror 32 may be a free-form concave mirror in which the second reflective surface 32a is defined by a free-form surface. The convex mirror 33 may be a free-form convex mirror in which the third reflective surface 33a is defined by a free-form surface.

[0024] The freeform surfaces defining the first reflecting surface 31a, the second reflecting surface 32a, and the third reflecting surface 33a may be XY polynomial surfaces (also called SPS XYP surfaces) defined by the following equations (1) and (2). The XY polynomial surface is expanded into polynomials up to the 10th order that are added to the reference conic surface. Therefore, in equations (1) and (2), the sum of m and n is 10 or less. In equation (1), z is the sag of a plane parallel to the z-axis (also called the optical axis), c is the vertex curvature, and r is the radial distance (i.e., r 2 =x 2 +y 2 ) where k is the conic constant and Cj is a monomial x m y n This is the coefficient.

[0025]

number

[0026]

number

[0027] The first concave mirror 31, the second concave mirror 32, and the convex mirror 33 may be aspherical mirrors in which the first reflecting surface 31a, the second reflecting surface 32a, and the third reflecting surface 33a are defined by quadratic surfaces such as parabolas, ellipsoids, and hyperbolas. The first concave mirror 31, the second concave mirror 32, and the convex mirror 33 may also be spherical mirrors in which the first reflecting surface 31a, the second reflecting surface 32a, and the third reflecting surface 33a are defined by spheres.

[0028] The optical system 3 includes only reflective members such as the first concave mirror 31 and the second concave mirror 32, and does not include semi-transmitting and semi-reflective members such as half mirrors, beam splitters, and wire grid polarizers. Therefore, the optical system 3 can reduce the degradation of the resolution of the floating image F due to refraction, deflection, etc. of the image light L, and can also increase the utilization rate of the image light L. Furthermore, the optical system 3 can reduce the distortion of the floating image F as seen by the user 5. In particular, when the first concave mirror 31, the second concave mirror 32, and the convex mirror 33 are free-form mirrors, the optical system 3 can reduce the distortion of the floating image F as seen by the user 5, especially the distortion of the peripheral part of the floating image F.

[0029] The floating image display device 1 comprises a housing 7 that houses a display unit 2 and an optical system 3. The housing 7 has an aperture 7a through which the image light L emitted from the optical system 3 passes.

[0030] As shown in Figure 1, the cover member 4 is located in the optical path of the image light L between the optical system 3 and the imaging position 12 of the floating image F. The cover member 4 may be located in the opening 7a of the housing 7. The cover member 4 may at least partially cover the opening 7a.

[0031] The cover member 4 transmits a portion of the image light L emitted from the optical system 3, while blocking the other portion of the image light L emitted from the optical system 3.

[0032] As shown in Figure 3, the cover member 4 has a light-shielding portion 61 and a plurality of light-transmitting portions 62. The light-shielding portion 61 shields a portion of the image light L emitted from the optical system 3. The light-transmitting portions 62 transmit another portion of the image light L emitted from the optical system 3. A portion of the image light L transmitted through the light-transmitting portions 62 is diffracted. The image light L that is not diffracted by the light-transmitting portions 62 displays a high-resolution floating image F at the imaging position 12, and the image light L that is diffracted by the light-transmitting portions 62 displays an image (also called a virtual image) V with lower resolution than the floating image F on the emission surface of the cover member 4 (the surface on the user 5 side) or in the vicinity of the emission surface. The user 5 can see the floating image F displayed at the imaging position 12, and also see the virtual image V displayed behind the floating image F from the user 5's perspective, but it is easier to direct visual attention to the high-resolution floating image F. As a result, user 5 can easily compare the display positions of the floating image F and the virtual image V in the depth direction, and can perceive the floating image F with an improved sense of floating (the feeling that the floating image F appears to be floating in the air). In the following, it is assumed that the cover member 4 has a decorative film 6 which is composed of a light-shielding portion 61 and a plurality of light-transmitting portions 62.

[0033] The decorative film 6 may consist of a base material 63, a light-shielding layer 64, and a transmittance-adjusting layer 65, as shown in Figure 3.

[0034] The base material 63 is plate-shaped and has a surface 63a on the optical system 3 side (also called the incident surface) and a surface 63b on the user 5 side (also called the output surface). The base material 63 may transmit image light L with a predetermined transmittance. The predetermined transmittance may be, for example, 10 to 100%. The base material 63 may be made of a highly light-transmitting resin such as polyethylene terephthalate resin, polycarbonate resin, polystyrene resin, or acrylic resin. The base material 63 may be a flat plate with the incident surface 63a and the output surface 63b substantially perpendicular to the depth direction. The base material 63 may also be a flat plate with the incident surface 63a and the output surface 63b inclined with respect to the depth direction, or it may be a curved plate, bent plate, corrugated plate, or other curved plate shape.

[0035] The light-shielding layer 64 may be located on the incident surface 63a of the substrate 63. The light-shielding layer 64 may block the image light L with a predetermined shielding ratio. The predetermined shielding ratio may be, for example, 90 to 100%.

[0036] The light-shielding layer 64 may consist of a binder resin and light-absorbing particles dispersed in the binder resin. The binder resin may be, for example, an acrylic resin. The light-absorbing particles may be, for example, a black pigment, a gray pigment, a brown pigment, etc.

[0037] The light-shielding layer 64 may have a shape such as a roughly grid or mesh when viewed in the depth direction. The light-shielding layer 64 may form a design that is visible to the user 5. The design may be, for example, a wood grain pattern, a marble pattern, or a wallpaper pattern.

[0038] The transmittance adjustment layer 65 may be located on the incident surface 63a of the substrate 63. The transmittance adjustment layer 65 may be located on the incident surface 63a of the substrate 63 in areas where the light-shielding layer 64 is not located (gaps in the light-shielding layer 64, such as a roughly grid-like or mesh-like structure). The transmittance adjustment layer 65 may transmit image light L with a predetermined transmittance. The predetermined transmittance may be, for example, 90 to 100%.

[0039] The transmittance adjustment layer 65 may consist of a binder resin and light-absorbing particles dispersed in the binder resin. The binder resin may be, for example, an acrylic resin. The light-absorbing particles may be, for example, a black pigment, a gray pigment, a brown pigment, etc.

[0040] The light-shielding portion 61 is the portion of the decorative film 6 where the light-shielding layer 64 and the base material 63 overlap in the depth direction. The light-transmitting portion 62 is the portion of the decorative film 6 where the light-shielding layer 64 is absent when viewed in the depth direction.

[0041] As shown in Figure 4, when viewed in the depth direction, the decorative film 6 has a shape in which at least one of the multiple translucent portions 62 (also called translucent portion 62') has multiple sides 62a, 62b, ... At least one of the multiple sides 62a, 62b, ... does not have to be a line segment (straight line) in the strict sense, and may be curved. Also, the corner 62c formed by two adjacent sides 62a, 62b among the multiple sides 62a, 62b, ... does not have to be a corner in the strict sense, and may be rounded.

[0042] Multiple light-transmitting sections 62 may be configured to have a roughly circular or roughly polygonal shape. A roughly circular shape includes, for example, a circle, an ellipse, etc. A roughly polygonal shape includes, for example, a triangle, a quadrilateral, a pentagon, a hexagon, etc., and also includes a polygon in which at least one corner is rounded. A roughly polygonal shape may include a rounded rectangle (racetrack shape). A quadrilateral shape includes a rectangle (rectangle or square), a rhombus, a trapezoid, a kite shape, etc. At least one light-transmitting section 62' may have a roughly polygonal shape.

[0043] The multiple translucent portions 62 do not all have to have the same shape. The decorative film 6 may include at least one substantially circular translucent portion 62 and at least one translucent portion 62', as shown in Figure 4.

[0044] If the fine light-transmitting areas 62 are uniformly distributed, the user's visual attention will be less likely to be directed towards the light-blocking areas 61, and the user will be able to more easily see the floating image F with an improved sense of floating. The fine light-transmitting areas 62 may be light-transmitting areas 62 with an aperture width of, for example, about 1.0 mm or less. As will be described in detail later, if the light-transmitting areas 62 are too fine, the effect of diffraction of image light L in the light-transmitting areas 62 will increase, and there is a risk that the resolution of the floating image F will decrease.

[0045] Figures 5-7 show excerpts of the decorative film 6. As shown in Figure 5, the decorative film 6 may include a region where, when viewed in the depth direction, multiple light-transmitting sections 62 are arranged in a matrix, and light-shielding sections 61 are located in the gaps between the light-transmitting sections 62. The light-transmitting sections 62 may be rectangular in shape, with opening widths a1 in the first direction and b1 in the second direction being approximately 0.4 to 1.0 mm when viewed in the depth direction. The light-transmitting sections 62 may be square in shape, with opening widths equal in the first direction and the second direction. The light-shielding sections 61 may have widths c1 in the first and second directions being approximately 0.5 mm when viewed in the depth direction. The width of the light-shielding section 61 refers to the length of the portion located between adjacent light-transmitting sections 62, as shown in Figure 5.

[0046] As shown in Figure 6, the decorative film 6 may include a region where, when viewed in the depth direction, multiple light-transmitting portions 62 are arranged in a staggered pattern, and light-shielding portions 61 are located in the gaps between the light-transmitting portions 62. The light-transmitting portions 62 may be circular in shape with an opening width (diameter) a2 of approximately 0.4 to 1.0 mm when viewed in the depth direction. The light-shielding portions 61 may have a width b2 of approximately 0.5 mm in the first direction. The width of the light-shielding portions 61 refers to the length of the portion located between adjacent light-transmitting portions 62, as shown in Figure 6. The pitch (center-to-center distance) c2 between adjacent light-transmitting portions 62 in the first direction may be approximately 0.45 to 1.25 mm. The pitch d2 between adjacent light-transmitting portions 62 in the second direction may be approximately 0.8 to 1.4 mm.

[0047] The decorative film 6 may have a configuration in which multiple light-transmitting portions 62 are uniformly distributed when viewed in the depth direction. If the light-transmitting portions 62 are unevenly distributed, there will be areas on the decorative film 6 where light-blocking portions 61 are unevenly distributed, and the user's visual attention will be more easily drawn to these areas where light-blocking portions 61 are unevenly distributed. As a result, it will be difficult for the user 5 to see the floating image F. By having the light-transmitting portions 62 uniformly distributed, it is possible to make it difficult for the user 5's visual attention to be drawn to the light-blocking portions 61, and it will be easier for the user 5 to see the floating image F.

[0048] The decorative film 6 is not limited to the configuration shown in Figures 5 and 6. The decorative film 6 may include a plurality of light-shielding portions 61 and light-transmitting portions 62. The plurality of light-shielding portions 61 may be arranged in a substantially matrix on the incident surface 63a of the substrate 63. The plurality of light-shielding portions 61 may be substantially circular or substantially polygonal in shape. The light-transmitting portions 62 may be located in the gaps between the light-shielding portions 61.

[0049] As shown in Figure 7, the decorative film 6 may include a region in which, when viewed in the depth direction, multiple light-shielding portions 61 are arranged in a staggered pattern, and light-transmitting portions 62 are located in the gaps between the light-shielding portions 61. The light-shielding portions 61 may be circular in shape with an opening width (diameter) a3 of approximately 0.4 to 1.0 mm when viewed in the depth direction. The light-transmitting portions 62 may have a width b3 of approximately 0.5 mm in the first and second directions. The width of the light-shielding portions 61 refers to the length of the portion located between adjacent light-shielding portions 61, as shown in Figure 7. The pitch c3 between adjacent light-shielding portions 61 in the first direction may be approximately 0.45 to 1.25 mm. The pitch d3 between adjacent light-shielding portions 61 in the second direction may be approximately 0.8 to 1.4 mm.

[0050] The width of the light-shielding portion 61 (width in the first and / or second directions) may be determined based on the Landolt ring used in visual acuity tests for the human eye. For example, a person with visual acuity of 1.0 can distinguish a gap (break in the ring) with a width of approximately 1.454 mm in a Landolt ring with a diameter of approximately 7.272 mm from a distance of 5 m from the Landolt ring. Therefore, if user 5 has visual acuity of 1.0 and the distance between user 5's eye and the decorative film 6 is 650 mm, user 5 can see a light-shielding portion 61 with a width of approximately 0.19 mm. By making the width of the light-shielding portion 61 approximately 0.19 mm or less, it becomes more difficult for user 5 to see the light-shielding portion 61, and user 5's visual attention is less likely to be directed towards the light-shielding portion 61. As a result, user 5 can see a floating image F with an improved sense of floating.

[0051] The width of the light-shielding portion 61 may be approximately 0.5 mm or less. According to experiments by the inventors, if the light-shielding portion 61 has a uniform pattern, it was found that if the width of the light-shielding portion 61 is approximately 0.5 mm or less, the user 5 will have difficulty noticing the light-shielding portion 61. The aperture width of the multiple light-transmitting portions 62 may be approximately 0.4 mm or more. In this case, it is possible to reduce the degradation of the resolution of the floating image F while making it difficult for the user 5 to notice the light-shielding portion 61. Therefore, the user 5 can see the floating image F with an improved sense of floating.

[0052] The decorative film 6 is not limited to the configuration shown in Figure 3. The decorative film 6 may be composed of two substrates 63, a light-shielding layer 64, and a transmittance adjustment layer 65, as shown in Figure 8. The two substrates 63 include a substrate 63 located on the optical system 3 side (also called the first substrate) and a substrate 63 located on the user 5 side (also called the second substrate). The second substrate 63 may be arranged parallel to the first substrate 63. The light-shielding layer 64 is located between the first substrate 63 and the second substrate 63. The transmittance adjustment layer 65 is located on the incident surface 63a of the first substrate 63. The light-shielding layer 64 may be substantially grid-like when viewed in the depth direction. The transmittance adjustment layer 65 may be composed of a binder resin and light-absorbing particles dispersed in the binder resin. The binder resin may be, for example, an acrylic resin. The light-absorbing particles may be, for example, a black pigment, a gray pigment, a brown pigment, etc. The transmittance adjustment layer 65 may transmit image light L at a predetermined transmittance. The predetermined transmittance may be 90-100%, or 95-100%. The light-transmitting portion 62 may be defined by the area where the light-shielding layer 64 does not exist when the decorative film 6 is viewed in the depth direction.

[0053] This section explains the effect of diffraction of image light L in the light-transmitting section 62 on the modulation transfer function (MTF) which represents the resolution (contrast value) of the floating image F. The following sections describe the cases where the light-transmitting section 62 is circular and where it is rectangular. MTF is a performance index used to evaluate the resolution of the optical system 3 and can be used as a resolution index to evaluate the resolution of the floating image F. MTF is a function of spatial frequency ν (cycles / millimeter), and is maximum when spatial frequency ν is 0. MTF may be normalized so that its maximum value is 1; in this case, the closer the MTF value is to 1, the higher the resolution of the floating image F. In the following explanation, it is assumed that MTF is normalized so that its maximum value is 1.

[0054] Optical devices such as imaging devices and display devices can be said to be able to capture or display high-resolution images over a wide range of spatial frequencies ν if the MTF value is 0.6 or higher at a spatial frequency ν of 3 [cycles / mm].

[0055] First, let's explain the case where the translucent portion 62 is circular. The intensity distribution I(r) of the diffracted light produced by the circular translucent portion 62 (see Figure 9) can be expressed using the JINC function. Here, the JINC function is J1(r) / r (where r is the position coordinate), and J1(r) is the Bessel function of the first kind. The I(ν) obtained by Fourier transforming the intensity distribution I(r) of the diffracted light is also called the optical transfer function of the translucent portion 62, and when the translucent portion 62 is circular, it can be expressed by the following equation (3).

[0056]

number

[0057] In equation (3), φ is expressed by the following equation (4), where ν is the spatial frequency, λ is the wavelength of the image light L, and NA is the numerical aperture of the decorative film 6.

[0058]

number

[0059] In equation (4), NA is expressed by the following equation (5), where D is the aperture width (diameter) of the light-transmitting section 62, f is the projection distance of the floating image F, and n is the refractive index of the medium. Note that f is the projection distance of the floating image F, which is the projection distance in the depth direction (Z-axis direction) relative to the decorative film 6.

[0060]

number

[0061] The optical system 3 of the floating image display device 1 can reduce the degradation of the resolution of the floating image F due to refraction, deflection, etc. of the image light L, and can also reduce the distortion of the floating image F. In the floating image display device 1, the degradation of the resolution of the floating image F that occurs in the optical system 3 is small, and the degradation of the resolution of the floating image F occurs substantially in the decorative film 6. Therefore, the MTF of the floating image F can be expressed by equation (3).

[0062] Figure 10 is a graph showing the relationship between the MTF expressed by equation (3) and the spatial frequency ν. To obtain the results shown in Figure 10, the projection distance f of the floating image F was set to 150 mm, the wavelength λ to 550 nm (green light), and the refractive index n of the medium (air) to 1.0. In the graph of Figure 10, the solid line corresponds to D=2.0 mm, the dashed line corresponds to D=1.0 mm, the dashed line corresponds to D=0.75 mm, and the dashed line corresponds to D=0.5 mm.

[0063] As can be seen from Figure 10, the resolution of the floating image F decreases as the diameter D of the light-transmitting portion 62 decreases. If the diameter D of the light-transmitting portion 62 is 0.75 mm or more, the MTF value can be set to 0.6 or more when the spatial frequency ν is 3 cycles / millimeter, allowing the user 5 to see a high-resolution floating image F.

[0064] Next, the case where the light-transmitting portion 62 is rectangular will be described. The intensity distribution I(r) of diffracted light generated by the rectangular light-transmitting portion 62 (see FIG. 11) can be expressed using the sinc function. Here, the sinc function mentioned is sin(r) / r. When the light-transmitting portion 62 is rectangular, the optical transfer function I(ν) of the light-transmitting portion 62 is expressed by the following formula (6).

[0065] [Number]

[0066] I in formula (6) x,y (ν) comprehensively represents the optical transfer function I x (ν) in the first direction and the optical transfer function I y (ν) in the second direction. Also, D x,y represents the aperture width D x of the light-transmitting portion 62 in the first direction and the aperture width D y of the light-transmitting portion 62 in the second direction in a comprehensive manner. Regarding ν, λ, and f in formula (6), they are the same as in formulas (3) to (5).

[0067] As described above, in the floating image display device 1, the resolution degradation of the floating image F generated in the optical system 3 is small, and the resolution degradation of the floating image F substantially occurs in the decorative film 6. Therefore, the MTF of the floating image F may be expressed by formula (6).

[0068] FIG. 12 is a graph showing the relationship between the MTF expressed by formula (6) and the spatial frequency ν. In obtaining the results shown in FIG. 12, the protrusion distance f of the floating image F was set to 150 mm, the wavelength λ was set to 550 nm (green light), and the refractive index n of the medium (air) was set to 1.0. In the graph of FIG. 12, the solid line corresponds to D x,y = 2.0 mm, the dashed line corresponds to D x,y = 1.0 mm, the dash-dotted line corresponds to D x,y = 0.75 mm, the dotted line corresponds to D x,y = 0.65 mm, and the double-dashed line corresponds to D x,y = 0.5 mm.

[0069] As can be seen from Figure 12, the aperture width D of the light-transmitting portion 62 in the first direction x As the size decreases, the resolution of the floating image F in the first direction decreases, and the aperture width D of the light-transmitting section 62 in the second direction decreases. y As the size decreases, the resolution of the floating image F in the second direction decreases. Aperture width D of the light-transmitting section 62 x,y If the value is 0.65 mm or greater, the MTF value can be set to 0.6 or greater when the spatial frequency ν is 3 cycles / millimeter, allowing the user 5 to see a high-resolution floating image F.

[0070] As can be seen from Figures 10 and 12, when the light-transmitting portion 62 is rectangular, the resolution of the floating image F is less likely to deteriorate compared to when the light-transmitting portion 62 is circular. Therefore, by making the light-transmitting portion 62 rectangular, the deterioration of the resolution of the floating image F can be reduced, and the user's visual attention is less likely to be directed towards the light-shielding portion 61. Although not explained here, when the light-transmitting portion 62 has multiple sides, the deterioration of the resolution of the floating image F can be reduced compared to when the light-transmitting portion 62 is circular, and the user's visual attention is less likely to be directed towards the light-shielding portion 61, thereby improving the floating sensation of the floating image F. Furthermore, when the light-transmitting portion 62 is roughly polygonal, especially rectangular, the deterioration of the resolution of the floating image F can be reduced even further, and the user's visual attention is less likely to be directed towards the light-shielding portion 61, thereby further improving the floating sensation of the floating image F.

[0071] The floating image display device 1 has at least one light-transmitting section 62' among the multiple light-transmitting sections 62, which has multiple sides. This reduces the degradation of the resolution of the floating image F and makes it less likely for the user 5's visual attention to be directed towards the light-shielding section 61. As a result, the user 5 can see a floating image F with an improved sense of floating by comparing the display position of the high-resolution floating image F with the display position of the low-resolution virtual image V. Therefore, the sense of floating of the floating image F seen by the user 5 can be improved. In addition, more than half of the multiple light-transmitting sections 62 of the floating image display device 1 may be light-transmitting sections 62'. In this case, the degradation of the resolution of the floating image F can be further reduced, and the user 5's visual attention can be less likely to be directed towards the light-shielding section 61. As a result, the user 5 can see a floating image F with an even improved sense of floating.

[0072] The light-transmitting portion 62' may be substantially polygonal in shape. In this case, the degradation of the resolution of the floating image F can be further reduced, and the user's visual attention can be less likely to be directed towards the light-shielding portion 61. As a result, the user 5 can perceive the floating image F with an improved sense of floating.

[0073] The light-transmitting portion 62' may be rectangular in shape. In this case, the degradation of the resolution of the floating image F can be further reduced, and the user's visual attention can be less likely to be directed towards the light-shielding portion 61. As a result, the user 5 can perceive a floating image F with improved floating sensation.

[0074] Aperture width D of the light-transmitting section 62' x,y This may be greater than or equal to the width of the portion of the light-shielding portion 61 located between the light-transmitting portion 62' and the light-transmitting portion 62 adjacent to the light-transmitting portion 62'. In this case, the degradation of the resolution of the floating image F is reduced, and the user's visual attention is less likely to be directed towards the light-shielding portion 61. As a result, the user 5 can perceive a floating image F with an improved sense of floating.

[0075] If the light-transmitting portion 62' is rectangular, the aperture width of the light-transmitting portion 62' may be 0.65 mm or more. In this case, the MTF value of the light transmitted through the light-transmitting portion 62' can be set to 0.6 or more at a spatial frequency ν of 3 cycles / millimeter. As a result, the degradation of the resolution of the floating image F is reduced, and the user's visual attention is less likely to be directed towards the light-shielding portion 61. As a result, the user 5 can perceive a floating image F with improved floating sensation.

[0076] Figure 13 is a magnified view of a portion of the display surface 2a as seen by the user 5 through the optical system 3. In Figure 13, the decorative film 6 is omitted, and adjacent pixels P1 and P2 and the black matrix BM located between pixels P1 and P2 are shown.

[0077] The image light L emitted from adjacent pixels P1 and P2 spreads out as image light L' at the imaging position 12 of the floating image F due to the diffraction effect caused by the decorative film 6. If the overlap of the image light L's becomes large, there is a risk that the resolution of the floating image F will deteriorate due to color mixing between pixels P1 and P2. The display unit 2 may be configured such that the pixel pitch between adjacent pixels P1 and P2 is greater than or equal to Rayleigh's resolution. In other words, the display unit 2 may be configured such that the center of the Airy disk of one of the pixels P1 and P2 does not overlap with the first dark ring of the Airy pattern of the other pixel. In this case, the deterioration of the resolution of the floating image F due to color mixing between pixels P1 and P2 can be reduced, and the user's visual attention will be less likely to be directed towards the light-shielding section 61. As a result, the user 5 can see a floating image F with an improved sense of floating.

[0078] The decorative film 6 may have an aperture width of the light-transmitting portion 62' that is greater than or equal to the width of one pixel of the display portion 2. In this case, it becomes easier to set the pixel pitch between adjacent pixels to be greater than or equal to Rayleigh's resolution, making it easier to reduce the degradation of the resolution of the floating image F due to color mixing between pixels. As a result, the user's visual attention is less likely to be directed towards the light-shielding portion 61, and the user can see the floating image F with an improved sense of floating. Multiple light-transmitting portions 62 may have an aperture width of greater than or equal to the width of one pixel of the display portion 2 for more than half of the light-transmitting portions 62. In this case, the degradation of the resolution of the floating image F due to color mixing between pixels is further reduced, and the user's visual attention is less likely to be directed towards the light-shielding portion 61. As a result, the user can see the floating image F with an even improved sense of floating.

[0079] As shown in Figure 14, the decorative film 6 may have different aperture widths for adjacent light-transmitting portions 62 in the first and / or second directions. In this case, the risk of increased overlap between image light rays L' at the imaging position 12 of the floating image F (see Figure 13) can be effectively reduced. This further reduces the degradation of the resolution of the floating image F and makes it less likely for the user 5's visual attention to be directed towards the light-shielding portion 61. As a result, the user 5 can perceive a floating image F with an improved sense of floating.

[0080] As shown in Figure 15, the decorative film 6 may include a first region R1 and a second region R2, each having one or more light-transmitting portions 62. The first region R1 and the second region R2 are at different distances from each other to the imaging position 12 of the floating image F, and the aperture width of the one or more light-transmitting portions 62 included in the first region R1 may be different from the aperture width of the one or more light-transmitting portions 62 included in the second region R2. For example, if the distance from the first region R1 to the imaging position 12 of the floating image F is greater than the distance from the second region R2 to the imaging position 12 of the floating image F, the aperture width of the one or more light-transmitting portions 62 included in the first region R1 may be greater than the aperture width of the one or more light-transmitting portions 62 included in the second region R2. In this case, even if the imaging surface 11 of the floating image F and the output surface of the decorative film 6 (the surface on the user 5 side) are not parallel, the aperture width of the light-transmitting portions 62 as seen from the user 5 can be kept substantially constant. As a result, the resolution may differ in each region of the floating image F, reducing the risk of a decrease in the display quality of the floating image F. The aperture width of one or more light-transmitting sections 62 included in the first region R1 may be the arithmetic mean of the aperture widths of one or more light-transmitting sections 62 included in the first region R1. The same applies to the aperture width of one or more light-transmitting sections 62 included in the second region R2.

[0081] As shown in Figure 16, the decorative film 6 may have a display area RD through which image light L is transmitted, and a peripheral area RP surrounding the display area. The display area RD may be the largest area in the decorative film 6 through which image light L can pass. The decorative film 6 may have aperture widths of one or more light-transmitting portions 62 included in the display area RD that are larger than the aperture widths of one or more light-transmitting portions 62 included in the peripheral area RP. Since the aperture widths of the light-transmitting portions 62 in the display area RD are relatively large, blurring of the floating image F due to diffraction of image light L can be reduced, and the resolution of the floating image F can be improved. Also, since the aperture widths of the light-transmitting portions 62 in the peripheral area RP are relatively small, the design layer of the light-shielding portion 61 provided in the peripheral area RP becomes more visible to the user 5, and the decorative effect of the design layer in the peripheral area RP can be improved. Note that the aperture widths of one or more light-transmitting portions 62 included in the display area RD may be the arithmetic mean of the aperture widths of one or more light-transmitting portions 62 included in the display area RD. The same applies to the aperture width of one or more light-transmitting sections 62 included in the surrounding region RP.

[0082] The cover member 4 may include a light-diffusing layer 8, as shown in Figures 17 and 18. The light-diffusing layer 8 may be located between the base material 63 and the light-shielding layer 64 in the decorative film 6. By diffusing ambient light L'' with the light-diffusing layer 8, the cover member 4 allows the user 5 to perceive a low-resolution diffused image (virtual image) V' of an object outside the device. Within the user 5's field of view, the virtual image V' may be located on or near the emission surface (emission surface 63b) of the decorative film 6, or it may be located inside the housing 7. By comparing the high-resolution floating image F with the low-resolution virtual image V', the user 5 can perceive a floating image F with an improved sense of floating.

[0083] The diffusion layer 8 may have the same outer shape as the light-shielding layer 64 when viewed in the depth direction. In this case, the image light L emitted from the optical system 3 is diffused by the diffusion layer 8, reducing the risk of stray light. The diffusion layer 8 may be enclosed by the light-shielding layer 64 when viewed in the depth direction. In other words, the diffusion layer 8 may be located on the incident surface 63a of the substrate 63 and covered by the light-shielding layer 64. In this case, the image light L emitted from the display unit 2 is diffused by the diffusion layer 8, effectively reducing the risk of stray light.

[0084] The diffusion layer 8 may consist of, for example, a binder resin and diffusion beads dispersed in the binder resin. The binder resin may be, for example, an acrylic resin or a urethane resin. The diffusion beads may consist of, for example, a silicone resin, a polystyrene resin, silica, calcium carbonate, etc. The diffusion beads may have shapes such as spherical, flaky, or cubic. The diffusion layer may also be a diffusion film.

[0085] The decorative film 6 shown in Figures 17 and 18 does not have a transmittance adjustment layer 65 (see Figure 3), but is not limited to this. The decorative film 6 may have a transmittance adjustment layer 65, as shown in Figures 19 and 20. The light-transmitting portion 62 may be a part where the light-shielding layer 64 does not exist when the decorative film 6 is viewed in the depth direction.

[0086] Furthermore, the decorative film 6 shown in Figures 17 and 18 has one base material 63, but is not limited to this. The decorative film 6 may also be composed of two base materials 63, a light-shielding layer 64, and a transmittance-adjusting layer 65, as shown in Figures 21 and 22.

[0087] A floating image display device according to the second embodiment of this disclosure will now be described. Figure 23 is a cross-sectional view showing the main components of the floating image display device of the second embodiment, and Figures 24 to 26 are cross-sectional views showing the cover member and the reflective polarizing plate. In Figure 23, the housing is omitted from the illustration. The floating image display device 1A of the second embodiment differs from the floating image display device 1 of the first embodiment in that the display unit 2 emits linearly polarized image light L and is equipped with a reflective polarizing plate 9, but the other components are the same, so the description of the similar components will be omitted.

[0088] As shown in Figure 23, the floating image display device 1A of the second embodiment comprises a display unit 2, an optical system 3, and a reflective polarizing plate 9.

[0089] The display unit 2 emits linearly polarized image light L. The following description will focus on the case where the display unit 2 emits S-wave polarized image light L, but it is not limited to this case; the display unit 2 may also emit P-wave polarized image light L.

[0090] As shown in Figure 23, the reflective polarizer 9 is located in the optical path of the image light L between the optical system 3 and the imaging position 12 of the floating image F. The reflective polarizer 9 transmits the image light L (S-wave polarized) emitted from the optical system 3 with relatively high transmittance. The reflective polarizer 9 can transmit the image light L, which is S-wave polarized, with a transmittance of, for example, 60% to 90%. The reflective polarizer 9 reflects a portion of the ambient light arriving from outside the device. The reflective polarizer 9 can reflect ambient light, which is P-wave polarized, with a reflectance of, for example, 60% to 90%.

[0091] The reflective polarizer 9 may be a wire grid polarizer comprising, for example, a substrate and a plurality of metal nanowires (metal nanowire grids) located on the surface of the substrate. The substrate may have a transmittance of 100% or nearly 100% for light in the visible light band. The substrate may be made of, for example, a resin material, a glass material, etc. The metal nanowires may be made of, for example, a metal material such as aluminum, chromium, or titanium oxide. The metal nanowires may be arranged along one direction. The reflective polarizer 9 can transmit light components vibrating in a direction perpendicular to the grid and can reflect light components vibrating in a direction parallel to the grid.

[0092] The reflective polarizing plate 9 reflects a portion of the ambient light L'''' arriving from outside the device, allowing the user 5 to perceive a reflected image (virtual image) V'' of an object O outside the device. Within the user 5's field of view, the virtual image V'' may be located inside the housing 7. By comparing the display positions of the floating image F and the virtual image V'' in the depth direction, the user 5 can perceive a floating image F with an improved sense of floating. The object O may be, for example, the user 5's face or head, or an object present around the user 5.

[0093] The floating image display device 1A may further include a cover member 4, as shown in Figure 24. The cover member 4 is located in the optical path of the image light L between the reflective polarizing plate 9 and the imaging position 12 of the floating image F. The cover member 4 may be in contact with the emission surface (the surface on the user 5 side) of the reflective polarizing plate 9. If the floating image display device 1A does not have a cover member 4, the resolution of the virtual image V displayed by the reflective polarizing plate 9 (in the user 5's field of view) will be higher than the resolution of the floating image F, making it difficult for the user 5 to direct their visual attention to the floating image F. By having a cover member 4 including a decorative film 6, the floating image display device 1A can maintain the high resolution of the floating image F while degrading (reducing) the resolution of the virtual image V. This makes it difficult for the user 5 to direct their visual attention to the virtual image V. As a result, the user 5 can perceive a floating image F with an improved sense of floating. Since the decorative film 6 has the same configuration as the decorative film 6 of the floating image display device 1, its description will be omitted.

[0094] The reflective polarizer 9 may be located on the side of the decorative film 6 that faces the optical system 3. A resin substrate 68 may be placed between the decorative film 6 and the reflective polarizer 9.

[0095] The decorative film 6 may have a texture layer 66 located on the exit surface 63b of the substrate 63. The texture layer 66 may have a thick film portion 66a and a thin film portion 66b with different heights in the depth direction from the exit surface 63b. By forming irregularities on the exit surface 63b of the substrate 63, the decorative film 6 can have a sense of depth. This makes it possible to enhance the design of the floating image display device 1A. The decorative film 6 may also have a hard coat layer 67 located on the exit surface 63b of the substrate 63.

[0096] The cover member 4 may have a dimming film 10. The dimming film 10 may be positioned between the decorative film 6 and the reflective polarizing plate 9. The dimming film 10 can adjust the transmittance of light passing through it (hereinafter also referred to as light transmittance) by applying a voltage. The dimming film 10 can switch between a state of high light transmittance and a state of low light transmittance by applying a voltage. The dimming film 10 may be composed of, for example, polymer-dispersed liquid crystal, electrochromic material, etc.

[0097] The dimming film 10 may be controlled to have a high light transmittance when the display unit 2 is ON (displaying an image). As a result, the floating image display device 1A can form a high-resolution floating image F, and at the same time, reflect a portion of the ambient light L'' arriving from an object outside the device with the reflective polarizing plate 9, forming a low-resolution virtual image V'' within the user's field of view. Consequently, the user 5 can easily compare the display positions of the floating image F and the virtual image'' in the depth direction, and can perceive the floating image F with an improved sense of floating.

[0098] The dimming film 10 may be controlled to have a low light transmittance when the display unit 2 is OFF (not displaying an image). This allows the floating image display device 1A to absorb / scatter ambient light L''' with the dimming film 10. As a result, the design expressed by the design layer can be clearly seen by the user 5.

[0099] The floating image display device 1,1A includes a controller (not shown). The controller is connected to each component of the floating image display device 1,1A and controls each component.

[0100] The controller may have functions such as turning the display unit 2 ON / OFF, transmitting image signals to the display unit 2, and adjusting the brightness, chromaticity, frame frequency, etc., of the image displayed on the display unit 2. Furthermore, if the display unit 2 has a heat dissipation member or cooling member, the controller may have a function to adjust the temperature of the heat dissipation member or cooling member.

[0101] The controller may consist of one or more processors. The processors may include general-purpose processors configured to load specific programs and perform specific functions, and dedicated processors specialized for specific processing. Dedicated processors may include ASICs (Application Specific Integrated Circuits). Processors may also include PLDs (Programmable Logic Devices). PLDs may include FPGAs (Field-Programmable Gate Arrays). The controller may also be a System-on-a-Chip (SoC) or System-in-a-Package (SiP) configured with one or more processors working together.

[0102] The floating image display devices 1,1A may include a camera (not shown) for capturing images of the user's face 5. The camera may be a visible light camera or an infrared camera. The camera may include, for example, a CCD (Charge Coupled Device) or CMOS (Complementary Metal Oxide Semiconductor) image sensor. If the camera is an infrared camera, the decorative film 6 may transmit infrared light. In this case, the user's face can be captured by a camera placed inside the housing.

[0103] The controller may detect the position of the user's eyes based on the imaging data output from the camera. The controller may deform the image displayed on the display unit 2 based on the detected eye position. In this case, even if the position of the user's eyes moves, it becomes possible to reduce the distortion of the floating image F seen by the user 5.

[0104] The floating image display device 1,1A may include a drive unit that displaces and / or rotates at least one of the first concave mirror 31, the second concave mirror 32, and the convex mirror 33. The controller may control the drive unit to displace and / or rotate at least one of the first concave mirror 31, the second concave mirror 32, and the convex mirror 33 of the floating image display device 1,1A based on the detected position of the user's eyes 5. In this case, even when the position of the user's eyes 5 moves, it is possible to reduce the distortion of the floating image F seen by the user 5. The drive unit may include, for example, a motor, a piezoelectric element, etc.

[0105] The floating image display devices 1 and 1A may be configured such that a portion of the edge of the first concave mirror 31 and a portion of the edge of the second concave mirror 32 are in contact. For example, in the floating image display device 1 of Figures 1 and 2 and the floating image display device 1A of Figure 23, the upper edge of the first concave mirror 31 and the lower edge of the second concave mirror 32 may be in contact. In this case, the floating image display devices 1 and 1A can be made smaller in the height direction. Furthermore, since there is no gap between the upper edge of the first concave mirror 31 and the lower edge of the second concave mirror 32, leakage of image light L from the gap can be reduced, and as a result, the risk of a decrease in the brightness of the floating image F can be reduced.

[0106] The first concave mirror 31, the second concave mirror 32, and the convex mirror 33 may be made of a metal such as aluminum. The first concave mirror 31, the second concave mirror 32, and the convex mirror 33 may be made of a resin body and a reflective layer located on the main surface of the body. In this case, the weight of the first concave mirror 31, the second concave mirror 32, and the convex mirror 33 can be reduced compared to the case where the first concave mirror 31, the second concave mirror 32, and the convex mirror 33 are made of metal, and as a result, the weight of the floating image display device 1,1A can be reduced. The body may be made of a resin such as polyethylene terephthalate resin, acrylic resin, or polystyrene resin. The reflective layer may be a thin film made of a metal such as aluminum or silver.

[0107] Although embodiments of this disclosure have been described in detail above, this disclosure is not limited to the embodiments described above, and various modifications and improvements are possible without departing from the gist of this disclosure.

[0108] This disclosure can be implemented in the following manner (1) to (22).

[0109] (1) Display unit and, An optical system that forms an image of a floating real image from the image light emitted from the display unit, The optical system and the imaging position of the floating image are provided, The floating image display device comprises a cover member having a light-shielding portion that blocks a portion of the image light and a plurality of light-transmitting portions that transmit another portion of the image light, wherein at least one of the plurality of light-transmitting portions has a shape with multiple sides.

[0110] (2) The floating image display device according to (1) above, wherein the at least one light-transmitting portion is substantially polygonal in shape.

[0111] (3) The floating image display device according to (1) or (2) above, wherein at least one light-transmitting portion is rectangular in shape.

[0112] (4) The floating image display device according to any one of (1) to (3) above, wherein the opening width of the at least one light-transmitting portion is equal to or greater than the width of the portion of the light-shielding portion located between the at least one light-transmitting portion and the light-transmitting portion adjacent to the at least one light-transmitting portion.

[0113] (5) The floating image display device according to any one of (1) to (4) above, wherein at least one light-transmitting portion has an aperture width such that the modulation transfer function, which is the contrast value of the floating image and normalized to a maximum value of 1, is 0.6 or more at a spatial frequency of 3 cycles / millimeter.

[0114] (6) The floating image display device according to any one of (1) to (5) above, wherein the aperture width of at least one light-transmitting portion is 650 μm or more.

[0115] (7) The display unit includes a plurality of pixels, The floating image display device according to any one of (1) to (6) above, wherein the aperture width of at least one light-transmitting portion is greater than or equal to the width of one pixel.

[0116] (8) The floating image display device according to any one of (1) to (7) above, wherein the aperture width of the plurality of light-transmitting portions is 400 μm or more.

[0117] (9) The cover member includes a first region and a second region, each having one or more light-transmitting portions, The first region and the second region are such that the distances from the floating image to the imaging position are different from each other. A floating image display device according to any one of (1) to (8) above, wherein the aperture width of one or more light-transmitting portions included in the first region is different from the aperture width of one or more light-transmitting portions included in the second region.

[0118] (10) The floating image display device according to any one of (1) to (9) above, wherein the cover member includes a light-diffusing layer.

[0119] (11) Display unit and, An optical system that forms an image of a floating real image from the image light emitted from the display unit, The optical system includes a reflective polarizing plate located between the optical system and the imaging position of the floating image, The reflective polarizing plate transmits polarized light having a polarization axis in a first direction and reflects polarized light having a polarization axis in a second direction perpendicular to the first direction, in a floating image display device.

[0120] (12) The floating image display device according to (11), further comprising a cover member positioned between the imaging position of the floating image and the reflective polarizing plate.

[0121] (13) The floating image display device according to (12) above, wherein the cover member has a light-shielding portion that blocks a portion of the image light and a plurality of light-transmitting portions that transmit another portion of the image light, and at least one of the plurality of light-transmitting portions has a shape with multiple sides.

[0122] (14) The floating image display device according to (13) above, wherein the at least one light-transmitting portion is substantially polygonal in shape.

[0123] (15) The floating image display device according to (13) or (14) above, wherein the at least one light-transmitting portion is rectangular in shape.

[0124] (16) The floating image display device according to any one of (13) to (15), wherein the opening width of the at least one light-transmitting portion is greater than or equal to the width of the portion of the light-shielding portion located between the at least one light-transmitting portion and the light-transmitting portion adjacent to the at least one light-transmitting portion.

[0125] (17) The floating image display device according to any one of (13) to (16), wherein the at least one light-transmitting portion has an aperture width such that the modulation transfer function, which is the contrast value of the floating image and normalized to a maximum value of 1, is 0.6 or more at a spatial frequency of 3 cycles / millimeter.

[0126] (18) The floating image display device according to any one of (13) to (17) above, wherein the aperture width of at least one light-transmitting portion is 650 μm or more.

[0127] (19) The display unit includes a plurality of pixels, A floating image display device according to any one of (13) to (18) above, wherein the aperture width of at least one light-transmitting portion is greater than or equal to the width of one pixel.

[0128] (20) The floating image display device according to any one of (13) to (19) above, wherein the aperture width of the plurality of light-transmitting portions is 400 μm or more.

[0129] (21) The cover member includes a first region and a second region, each having one or more light-transmitting portions, The first region and the second region are such that the distances from the floating image to the imaging position are different from each other. A floating image display device according to any one of (13) to (20) above, wherein the aperture width of one or more light-transmitting portions included in the first region is different from the aperture width of one or more light-transmitting portions included in the second region.

[0130] (22) The floating image display device according to any one of (12) to (21) above, wherein the cover member includes a light-diffusing layer. Industrial application fields

[0131] The floating image display device disclosed herein enables touchless operation of floating images and can be used in a variety of product fields, including, but not limited to, the following: for example, communication devices that conduct conversations and communications with floating images; medical consultation devices in which doctors conduct interviews with patients through floating images; navigation devices and driving control devices for vehicles such as automobiles; order placement and receiving devices and cash register devices for stores, etc.; operation panels for buildings, elevators, etc.; learning devices that conduct or receive lessons with floating images; office equipment that conducts business communications and instructions with floating images; amusement machines that play games with floating images; projection devices that project images onto the ground, walls, etc. in amusement parks, game centers, etc.; simulator devices that conduct simulated experiments using floating images in universities, medical institutions, etc.; large displays that display prices, etc. in markets, stock exchanges, etc.; and video viewing devices for viewing images of floating images. [Explanation of symbols]

[0132] 1.1A Floating Image Display Device 2 Display section 2a Display surface 3 Optical system 4 Cover component 5 User 6. Decorative film 7 cabinets 7a aperture 8. Diffusion layer 9 Reflective polarizer 10 Dimming Film 11 Image plane 12. Image formation position 31 1st concave mirror 31a 1st reflective surface 32 Second concave mirror 32a 2nd reflective surface 33 Convex mirror 33a Third reflective surface 61 Light-shielding part 62,62' Translucent part 62a, 62b sides 62c Corner 63 Base material 63a Entrance plane 63b Output surface 64 Light blocking layer 65 Transmittance adjustment layer 66 texture layers 66a Thick film part 66b Thin film part 67 Hard court layer 68 Resin substrate F Levitation L Image Light

Claims

1. Display unit and An optical system that forms an image of a floating real image from the image light emitted from the display unit, The optical system and the imaging position of the floating image are provided, A floating image display device, wherein the cover member has a light-shielding portion that blocks a portion of the image light and a plurality of light-transmitting portions that transmit another portion of the image light, and at least one of the plurality of light-transmitting portions has a shape with multiple sides.

2. The floating image display device according to claim 1, wherein the at least one light-transmitting portion has a substantially polygonal shape.

3. The floating image display device according to claim 1 or 2, wherein the at least one light-transmitting portion is rectangular in shape.

4. The floating image display device according to claim 1 or 2, wherein the opening width of the at least one light-transmitting portion is greater than or equal to the width of the portion of the light-shielding portion located between the at least one light-transmitting portion and the light-transmitting portion adjacent to the at least one light-transmitting portion.

5. The floating image display device according to claim 1 or 2, wherein the at least one light-transmitting portion has an aperture width such that the modulation transfer function, which is the contrast value of the floating image and whose maximum value is normalized to 1, is 0.6 or more at a spatial frequency of 3 cycles / millimeter.

6. The floating image display device according to claim 1 or 2, wherein the aperture width of at least one light-transmitting portion is 650 μm or more.

7. The display unit includes a plurality of pixels, The floating image display device according to claim 1 or 2, wherein the aperture width of at least one light-transmitting portion is greater than or equal to the width of one pixel.

8. The floating image display device according to claim 1 or 2, wherein the aperture width of the plurality of light-transmitting portions is 400 μm or more.

9. The cover member includes a first region and a second region, each having one or more light-transmitting portions. The first region and the second region are such that the distances from the floating image to the imaging position are different from each other. The floating image display device according to claim 1 or 2, wherein the aperture width of one or more light-transmitting portions included in the first region is different from the aperture width of one or more light-transmitting portions included in the second region.

10. The floating image display device according to claim 1 or 2, wherein the cover member includes a light-diffusing layer.

11. Display unit and An optical system that forms an image of a floating real image from the image light emitted from the display unit, The optical system includes a reflective polarizer positioned between the optical system and the imaging position of the floating image, The reflective polarizing plate transmits polarized light having a polarization axis in a first direction and reflects polarized light having a polarization axis in a second direction perpendicular to the first direction, in a floating image display device.

12. The floating image display device according to claim 11, further comprising a cover member positioned between the imaging position of the floating image and the reflective polarizing plate.

13. The floating image display device according to claim 12, wherein the cover member has a light-shielding portion that blocks a portion of the image light and a plurality of light-transmitting portions that transmit another portion of the image light, and at least one of the plurality of light-transmitting portions has a shape with multiple sides.

14. The floating image display device according to claim 13, wherein the at least one light-transmitting portion has a substantially polygonal shape.

15. The floating image display device according to claim 13 or 14, wherein the at least one light-transmitting portion is rectangular in shape.

16. The floating image display device according to claim 13 or 14, wherein the opening width of the at least one light-transmitting portion is greater than or equal to the width of the portion of the light-shielding portion located between the at least one light-transmitting portion and the light-transmitting portion adjacent to the at least one light-transmitting portion.

17. The floating image display device according to claim 13 or 14, wherein the at least one light-transmitting portion has an aperture width such that the modulation transfer function, which is the contrast value of the floating image and whose maximum value is normalized to 1, is 0.6 or more at a spatial frequency of 3 cycles / millimeter.

18. The floating image display device according to claim 13 or 14, wherein the aperture width of at least one light-transmitting portion is 650 μm or more.

19. The display unit includes a plurality of pixels, The floating image display device according to claim 13 or 14, wherein the aperture width of at least one light-transmitting portion is greater than or equal to the width of one pixel.

20. The floating image display device according to claim 13 or 14, wherein the aperture width of the plurality of light-transmitting portions is 400 μm or more.

21. The cover member includes a first region and a second region, each having one or more light-transmitting portions. The first region and the second region are such that the distances from the floating image to the imaging position are different from each other. The floating image display device according to claim 13 or 14, wherein the aperture width of the one or more light-transmitting portions included in the first region is different from the aperture width of the one or more light-transmitting portions included in the second region.

22. The floating image display device according to claim 12 or 13, wherein the cover member includes a light-diffusing layer.

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