Aerial image forming device and laminate

Abstract

To provide an aerial image forming device with which generation of ghost images is suppressed and the impact of white blurs is reduced, and a laminate for forming the aerial image forming device.SOLUTION: Provided is an aerial image forming device 10 comprising: a display unit 1 having a display surface, with light emitted from the display surface; a light diffusion control unit 2 for diffusing or transmitting the light depending on its incident angle; and a light-transmission / image formation unit 3 for transmitting the light having passed through the light diffusion control unit 2 and forming an image at a position on the side opposite the light diffusion control unit 2. The light diffusion control unit 2 is either a film laminate 2a in which at least two layers of a film are stacked one on another that has a louver-shaped regular internal structure provided with a plurality of plate-like regions whose refractive index is relatively high in a region whose refractive index is relatively low, or a single film 2b in which louver-shaped regular internal structure provided with a plurality of plate-like regions whose refractive index is relatively high in a region whose refractive index is stacked at least two high.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an aerial image forming device and a laminate for forming the aerial image forming device. [Background technology]

[0002] Aerial images are images formed at any position in space by reflecting and refracting light emitted from a light source using optical elements. There is no screen or display at the position where the aerial image is displayed, so viewers who view the aerial image experience a mysterious sensation. For this reason, aerial images have been used in a variety of applications in recent years, including virtual reality.

[0003] For example, Patent Document 1 discloses an aerial image forming device that includes at least a display unit and a light-transmitting imaging unit, in which an image (real image) displayed on the display unit is displayed as an aerial image primarily through the action of the light-transmitting imaging unit. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-060752 Summary of the Invention [Problem to be solved by the invention]

[0005] When an aerial image forming device is operated, an unintended image called a ghost image may be displayed simultaneously with the aerial image. The occurrence of a ghost image is unintended and cannot be said to accurately reflect the real image. In addition, the ghost image may overlap with the aerial image, making it difficult to clearly view the aerial image.

[0006] In order to suppress the occurrence of such ghost images, the inventors have found that the occurrence of ghost images can be effectively suppressed by providing a light diffusion control film in the aerial image forming device that diffuses or transmits light depending on the angle of incidence. However, they have also confirmed that in this case, a white haze may appear on the aerial image, hindering good visibility.

[0007] The present invention has been made in consideration of the above-described situation, and aims to provide an aerial image forming device that effectively suppresses the occurrence of ghost images and reduces the effects of haze, as well as a laminate for forming the aerial image forming device. [Means for solving the problem]

[0008] In order to achieve the above-mentioned object, first, the present invention provides an aerial image forming device comprising: a display unit having a display surface and emitting light from the display surface; a light diffusion control unit arranged on the display surface side of the display unit and diffusing or transmitting the light depending on the angle of incidence; and a light-transmitting image forming unit laminated on the side of the light diffusion control unit opposite the display unit and transmitting the light that has passed through the light diffusion control unit and forming an image at a position on the side opposite the light diffusion control unit, wherein the light diffusion control unit is a film laminate formed by laminating at least two films each having a louvered regular internal structure with a plurality of plate-like regions with a relatively high refractive index within a region with a relatively low refractive index, or a single film formed by laminating at least two layers of a louvered regular internal structure with a plurality of plate-like regions with a relatively high refractive index within a region with a relatively low refractive index (Invention 1).

[0009] In the above invention (Invention 1), it is preferable that the display unit is arranged relative to the light diffusion control unit and the light-transmitting image forming unit so that the display surface and the surface of the light diffusion control unit opposite the light-transmitting image forming unit are non-parallel (Invention 2).

[0010] In the above inventions (Inventions 1 and 2), for at least one of the regular internal structures within the film stack or within the single film, if a direction perpendicular to the longitudinal direction of the plate-like region and existing within the plane opposite the translucent imaging section in the light diffusion control section is defined as a first direction, it is preferable that each of the plate-like regions is inclined toward the first direction within the light diffusion control section (Invention 3).

[0011] In the above inventions (Inventions 1 to 3), it is preferable that the light-transmitting imaging section includes a retrotransmitting optical element that retrotransmits incident light (Invention 4).

[0012] In the above invention (Invention 4), the retrotransmitting optical element is preferably formed by stacking two layers each having a plurality of reflective surfaces, and in each of the two layers, the plurality of reflective surfaces are arranged perpendicular to one side of the retrotransmitting optical element and at a predetermined distance from each other, and the two layers are preferably stacked so that the reflective surface in one layer is perpendicular to the reflective surface in the other layer (Invention 5).

[0013] Secondly, the present invention provides a laminate comprising a light-transmitting imaging section that forms an image of light incident from one side at a position on the other side of the light-transmitting imaging section, and a light diffusion control section laminated on one side of the light-transmitting imaging section, wherein the light diffusion control section diffuses or transmits light that enters the light diffusion control section depending on the angle of incidence, and the light diffusion control section is a film laminate formed by laminating at least two films having a louvered regular internal structure with a plurality of plate-like regions with a relatively high refractive index within a region with a relatively low refractive index, or a single film formed by laminating at least two layers of a louvered regular internal structure with a plurality of plate-like regions with a relatively high refractive index within a region with a relatively low refractive index (Invention 6). [Effects of the Invention]

[0014] The aerial image forming device according to the present invention can effectively suppress the occurrence of ghost images and reduce white haze. Furthermore, the laminate according to the present invention can form the above-mentioned aerial image forming device. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a cross-sectional view schematically illustrating an example of an aerial image forming device according to an embodiment of the present invention. [Figure 2] FIG. 3 is a cross-sectional view schematically showing a light diffusion control section. [Figure 3] FIG. 2 is a perspective view schematically showing the internal structure of the light diffusion control film. [Figure 4] 10A and 10B are diagrams illustrating the relationship between the optical characteristics of a light diffusion control unit and light that forms an aerial image and a ghost image. [Figure 5] 1 is a cross-sectional view schematically showing light diffusion control sections according to Example 1, Comparative Example 1, and Comparative Example 2. FIG. [Figure 6] 10 is a graph showing the results of measurement of the optical characteristics of the light diffusion control portion in Test Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, an embodiment of the present invention will be described. [Aerial image forming device] Fig. 1 is a cross-sectional view schematically illustrating an example of an aerial image forming device according to this embodiment. As shown in Fig. 1, an aerial image forming device 10 according to this embodiment includes a display unit 1 having a display surface and emitting light from the display surface, a light diffusion control unit 2 disposed on the display surface side of the display unit 1 and diffusing or transmitting the light depending on the angle of incidence, and a light-transmitting image forming unit 3 disposed on the side of the light diffusion control unit 2 opposite the display unit 1 and transmitting the light that has passed through the light diffusion control unit 2 to form an image at a position on the side opposite the light diffusion control unit 2.

[0017] In this embodiment, the light diffusion control section 2 is a film laminate consisting of at least two films each having a louvered regular internal structure with a plurality of plate-like regions with a relatively high refractive index in a region with a relatively low refractive index, or a single film consisting of at least two layers of a louvered regular internal structure with a plurality of plate-like regions with a relatively high refractive index in a region with a relatively low refractive index.

[0018] FIG. 2 is a cross-sectional view that schematically shows the light diffusion control section 2 in this embodiment. In particular, FIG. 2(a) is a schematic cross-sectional view of the film laminate 2a. The film laminate 2a is formed by laminating two layers of light diffusion control films 21. Each light diffusion control film 21 has a regular internal structure in which plate-like regions 201 are regularly arranged. Furthermore, FIG. 2(b) is a schematic cross-sectional view of the single film 2b. In the single film 2b, two layers of regular internal structures in which plate-like regions 201 are regularly arranged are laminated.

[0019] The regular internal structure in the film laminate 2a (light diffusion control film 21) and the single film 2b will be described in more detail with reference to FIG. 3. FIG. 3 is a perspective view schematically illustrating the internal structure of the light diffusion control film 21. As shown in FIG. 3, the light diffusion control film 21 has a louver-like regular internal structure that includes multiple plate-like regions 201 with a relatively high refractive index within regions 202 with a relatively low refractive index. The regular internal structure of the light diffusion control film 21 allows incident light that is incident on the surface of the light diffusion control film 21 within a predetermined range of incident angles to exit while being strongly diffused at a predetermined angle of divergence. On the other hand, when the incident angle is outside the above range, the light is either transmitted without being diffused or is emitted with less diffusion than light incident within the range of incident angles. This property is also true for the single film 2b, which has a two-layer regular internal structure. The direction perpendicular to the longitudinal direction of the plate-shaped region 201 and present on the surface of the light diffusion control unit 2 opposite the translucent imaging unit 3 (the direction indicated by "D1" in Figure 3) is referred to as the "first direction."

[0020] In the aerial image forming device 10 according to this embodiment, when a desired image (real image) is displayed on the display surface of the display unit 1, an image (aerial image) formed by the real image being focused in the air can be seen at the position indicated by reference numeral "4" in Fig. 1 when viewed from a predetermined observation point 5. In this specification, the surface at the position indicated by reference numeral "4" will be referred to as the "aerial image observation surface."

[0021] In conventional aerial image forming devices, an image known as a ghost image may also be displayed along with the aerial image. A ghost image is an image that reflects a real image and is displayed around the aerial image on the aerial image observation surface 4, even though it is not displayed on the display surface of the display unit 1. To suppress the occurrence of such ghost images, optical elements that block only the light that contributes to the formation of ghost images are sometimes used. However, because these optical elements block a portion of the light emitted from the display unit 1, they reduce the brightness of the aerial image, making it difficult for the viewer to view the aerial image.

[0022] In contrast, the aerial image forming device 10 according to this embodiment is equipped with the light diffusion control unit 2, and is therefore able to effectively suppress the occurrence of ghost images while maintaining sufficient brightness of the aerial image. As will be explained below, this effect is presumed to be due to the action of the light diffusion control unit 2. However, this effect is not limited to this action, and the possibility of other effects also exists.

[0023] FIG. 4 is a diagram for explaining the action of the light diffusion control unit 2, and in particular, a diagram for explaining the relationship between the optical characteristics of the light diffusion control unit 2 and the light that forms the aerial image and the ghost image.

[0024] As described above, the light diffusion control unit 2 diffuses and transmits light incident within a predetermined incident angle range, and transmits light incident outside this incident angle range with almost no diffusion. The graph in FIG. 4 shows the relationship between the incident angle of light incident on the light diffusion control unit 2 and the haze value. Specifically, it shows that for light incident from an incident angle range of approximately -10° to approximately 10°, the haze value exceeds 80% (i.e., the light is diffused and transmitted). On the other hand, it shows that for light incident from an incident angle range of approximately -70° to approximately -20°, the haze value is approximately 15% (i.e., the light is transmitted with almost no diffusion). The incident angle at which the haze value fluctuates significantly (around -15° in FIG. 4) is sometimes referred to as the "threshold value."

[0025] Here, the "haze value" mentioned above differs from ordinary "haze" in that it is a measurement value obtained by placing a predetermined distance between the integrating sphere opening and the sample and varying the angle of incidence onto the sample. In the measurements herein, the predetermined distance is set to 20 mm, but the value is not particularly limited as long as it allows for confirmation of the straight transmission / diffuse transmission of incident light.

[0026] In the aerial image forming device 10 according to this embodiment, the light diffusion controller 2 exhibiting the above optical characteristics is located between the display unit 1 and the translucent imaging unit 3. This allows the light for forming the aerial image to reach the translucent imaging unit 3 effectively, while allowing the light for forming the ghost image to reach the translucent imaging unit 3 in a diffused state. This allows the viewer to clearly view the aerial image while making it difficult to view the ghost image. Furthermore, because the light diffusion controller 2 controls the diffusion of light rather than blocking light, it is possible to display the aerial image with sufficient brightness while suppressing the occurrence of ghost images.

[0027] Furthermore, by appropriately adjusting the type of light diffusion control unit 2 and the stacking state with the light-transmitting imaging unit 3, etc., so that the threshold is positioned between the range of incident angles of light for forming an aerial image and the range of incident angles of light for forming a ghost image, as shown in Figure 4, a better effect can be achieved.

[0028] Furthermore, in conventional aerial image forming devices, white haze occurs on the aerial image observation surface 4, which can hinder good visibility of the aerial image, but the aerial image forming device 10 of this embodiment can reduce the effects of such white haze. Here, white haze refers to a phenomenon in which the light of ghost images is diffused, causing the periphery of these images to appear white.

[0029] In the aerial image forming device 10 according to this embodiment, the light diffusion control section 2 uses a film laminate 2a formed by stacking at least two layers of light diffusion control film 21, or a single film 2b formed by stacking at least two layers of the above-described regular internal structure, thereby more effectively diffusing light passing through the light diffusion control section 2. As a result, it is possible to move the position where white haze caused by ghost images occurs away from the aerial image, or to suppress the occurrence of white haze itself. As a result, the aerial image forming device 10 according to this embodiment can suppress the effects of white haze and clearly view the aerial image.

[0030] 1.Display section The display unit 1 constituting the aerial image forming device 10 according to this embodiment is not particularly limited as long as it has a display surface and can display an image on the display surface and emit the light toward the light diffusion control unit 2 and the translucent imaging unit 3. For example, the display unit 1 can be a liquid crystal (LCD) display, a light emitting diode (LED) display, an organic electroluminescence (OLED) display, or the like.

[0031] The positional relationship between the display unit 1 and the light diffusion control unit 2 and the translucent imaging unit 3 is not particularly limited. As shown in FIG. 1, it is preferable that the display unit 1 and the light diffusion control unit 2 are sufficiently separated, with a space therebetween. It is also preferable that the display unit 1 is disposed relative to the light diffusion control unit 2 and the translucent imaging unit 3 so that the display surface of the display unit 1 and the surface of the light diffusion control unit 2 opposite to the translucent imaging unit 3 are non-parallel. This positional relationship makes it possible to display aerial images more clearly.

[0032] 2. Translucent imaging section The light-transmitting imaging unit 3 constituting the aerial image forming device 10 according to this embodiment is not particularly limited as long as it can transmit light originating from the display unit 1 and form an aerial image on a predetermined aerial image observation plane. An example of such a light-transmitting imaging unit 3 is a retrotransmitting optical element that retrotransmits incident light.

[0033] Although conventionally known retrotransmitting optical elements can be used, from the viewpoint of facilitating good aerial image formation, it is preferable to use a retrotransmitting optical element having a two-sided orthogonal reflector array structure or a retrotransmitting optical element having a two-sided corner reflector array structure, and it is more preferable to use a retrotransmitting optical element having a two-sided orthogonal reflector array structure. Examples of retrotransmitting optical elements having a two-sided orthogonal reflector array structure include those described in Japanese Patent No. 5085631. That is, it is preferable to use a retrotransmitting optical element having two layers stacked together, each layer having multiple reflective surfaces. In particular, in the retrotransmitting optical element, it is preferable that multiple reflective surfaces in each of the two layers are arranged perpendicular to one surface of the retrotransmitting optical element and at a predetermined distance from each other, and that the two layers are stacked so that the reflective surface in one layer is perpendicular to the reflective surface in the other layer. Specifically, a retrotransmitting optical element having a dihedral corner reflector array structure may have the structure described in International Publication WO2007 / 116639.

[0034] The thickness of the light-transmitting imaging section 3 is preferably 0.1 to 20 mm, more preferably 0.5 to 15 mm, particularly preferably 1 to 12 mm, further preferably 2 to 10 mm, and most preferably 4 to 8 mm. When the thickness of the light-transmitting imaging section 3 is within the above range, the aerial image forming device 10 according to this embodiment can more easily display a brighter aerial image.

[0035] 3. Light diffusion control section The light diffusion control unit 2 constituting the aerial image forming device 10 of this embodiment is not particularly limited as long as it is a film laminate 2a consisting of at least two light diffusion control films 21 having a louvered regular internal structure laminated together, as described above, or a single film 2b consisting of at least two layers of a louvered regular internal structure laminated together.

[0036] From the viewpoint of facilitating the formation of the regular internal structure, whether the light diffusion control section 2 is a film laminate 2a or a single film 2b, it is preferable that the light diffusion control film 21 and the single film 2b constituting the film laminate 2a are each formed by curing a composition for a light diffusion control section containing a high refractive index component and a low refractive index component having a refractive index lower than that of the high refractive index component. In particular, it is preferable that the high refractive index component and the low refractive index component each have one or two polymerizable functional groups.

[0037] From the perspective of the SDGs, the material that constitutes the light diffusion control section may be a material with a high biomass content, a material that can be recycled or reused, or a recycled or reused material.

[0038] (1) High refractive index component Preferred examples of high refractive index components include (meth)acrylic acid esters containing an aromatic ring, and particularly preferred are (meth)acrylic acid esters containing multiple aromatic rings. Examples of (meth)acrylic acid esters containing multiple aromatic rings include biphenyl (meth)acrylate, naphthyl (meth)acrylate, anthracyl (meth)acrylate, benzylphenyl (meth)acrylate, biphenyloxyalkyl (meth)acrylate, naphthyloxyalkyl (meth)acrylate, anthracyloxyalkyl (meth)acrylate, benzylphenyloxyalkyl (meth)acrylate, and the like, some of which are substituted with halogen, alkyl, alkoxy, alkyl halide, or the like. Among these, biphenyl (meth)acrylate is preferred from the viewpoint of facilitating the formation of a good regular internal structure, and specifically, o-phenylphenoxyethyl acrylate, o-phenylphenoxyethoxyethyl acrylate, and the like are preferred. In this specification, (meth)acrylic acid refers to both acrylic acid and methacrylic acid. The same applies to other similar terms.

[0039] The molecular weight of the high refractive index component is preferably 150 to 2500, particularly preferably 200 to 1500, and even more preferably 250 to 1000. Having the molecular weight within this range facilitates the formation of a light diffusion control section 2 having a desired regular internal structure. When the theoretical molecular weight of the high refractive index component can be determined based on its molecular structure, the molecular weight of the high refractive index component refers to this theoretical molecular weight. On the other hand, when the theoretical molecular weight is difficult to determine because the high refractive index component is, for example, a polymer component, the molecular weight of the high refractive index component refers to the weight-average molecular weight obtained as a value converted into standard polystyrene by gel permeation chromatography (GPC). In this specification, the weight-average molecular weight is measured using the GPC method and converted into standard polystyrene.

[0040] The refractive index of the high refractive index component is preferably 1.45 to 1.70, more preferably 1.50 to 1.65, particularly preferably 1.54 to 1.62, and even more preferably 1.56 to 1.59. This makes it easier to form light diffusion control parts 2 having a desired regular internal structure. Note that the refractive index in this specification means the refractive index of a predetermined component before curing the composition for light diffusion control part, and this refractive index is measured in accordance with JIS K0062:1992.

[0041] The content of the high refractive index component in the composition for light diffusion controlling portions is preferably 25 to 400 parts by mass, more preferably 50 to 350 parts by mass, particularly preferably 75 to 300 parts by mass, and even more preferably 100 to 200 parts by mass, relative to 100 parts by mass of the low refractive index component. This ensures that the regions derived from the high refractive index component and the regions derived from the low refractive index component are present in the desired ratio in the regular internal structure of the formed light diffusion controlling portions 2, making it easier to form the desired regular internal structure.

[0042] (2) Low refractive index component Preferred examples of the low refractive index component include urethane (meth)acrylate, (meth)acrylic polymers having (meth)acryloyl groups in their side chains, (meth)acryloyl group-containing silicone resins, and unsaturated polyester resins. Among these, urethane (meth)acrylate is particularly preferred because it is easy to form a good regular internal structure. More specifically, it is preferred to use a urethane (meth)acrylate formed from (a) a compound containing at least two isocyanate groups, (b) a polyalkylene glycol, and (c) a hydroxyalkyl (meth)acrylate.

[0043] Preferred examples of the (a) compound containing at least two isocyanate groups include aromatic polyisocyanates such as 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, and 1,4-xylylene diisocyanate, aliphatic polyisocyanates such as hexamethylene diisocyanate, alicyclic polyisocyanates such as isophorone diisocyanate and hydrogenated diphenylmethane diisocyanate, and biurets and isocyanurates thereof, as well as adducts thereof that are reaction products with low-molecular-weight active hydrogen-containing compounds such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, and castor oil. Among these, alicyclic polyisocyanates are preferred, and alicyclic diisocyanates are particularly preferred.

[0044] Preferred examples of the (b) polyalkylene glycol include polyethylene glycol, polypropylene glycol, polybutylene glycol, polyhexylene glycol, etc., and among these, polypropylene glycol is preferred. The weight-average molecular weight of the (b) polyalkylene glycol is preferably 2,300 to 19,500, more preferably 3,000 to 14,300, and even more preferably 4,000 to 12,300.

[0045] Preferred examples of the (c) hydroxyalkyl(meth)acrylate include 2-hydroxyethyl(meth)acrylate, 2-hydroxypropyl(meth)acrylate, 3-hydroxypropyl(meth)acrylate, 2-hydroxybutyl(meth)acrylate, 3-hydroxybutyl(meth)acrylate, and 4-hydroxybutyl(meth)acrylate, and among these, 2-hydroxyethyl(meth)acrylate is preferred.

[0046] The synthesis of urethane (meth)acrylate using the above-mentioned components (a) to (c) as raw materials can be carried out by a conventional method. In this case, the blending ratio of components (a) to (c) is preferably component (a):component (b):component (c)=1-5:1:1-5, particularly preferably 1-3:1:1-3, from the viewpoint of efficient synthesis of the urethane (meth)acrylate.

[0047] The weight average molecular weight of the low refractive index component is preferably 3000 to 20000, particularly preferably 5000 to 15000, and further preferably 7000 to 13000. This makes it easier to form the light diffusion controlling parts 2 having a desired regular internal structure.

[0048] The refractive index of the low refractive index component is preferably 1.30 to 1.59, more preferably 1.38 to 1.50, particularly preferably 1.42 to 1.49, and further preferably 1.46 to 1.48, which makes it easier to form the light diffusion controlling parts 2 having a desired regular internal structure.

[0049] (3) Other additives The composition for light diffusion control portion described above may contain other additives in addition to the high refractive index component and the low refractive index component, such as a polyfunctional monomer, a photopolymerization initiator, an antioxidant, an ultraviolet absorber, a light stabilizer, an antistatic agent, a polymerization accelerator, a polymerization inhibitor, an infrared absorber, a plasticizer, a diluting solvent, and a leveling agent.

[0050] Among the above, the composition for light diffusion controlling portion preferably contains a photopolymerization initiator, which makes it easier to efficiently form the light diffusion controlling portion 2 having a desired regular internal structure.

[0051] Examples of photopolymerization initiators include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylaminoacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-propan-1-one, 4-(2-hydroxyethoxy)phenyl-2-(hydroxy-2- propyl ketone, benzophenone, p-phenylbenzophenone, 4,4-diethylaminobenzophenone, dichlorobenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzyl dimethyl ketal, acetophenone dimethyl ketal, p-dimethylamine benzoic acid ester, oligo[2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propane], etc. These may be used alone or in combination of two or more.

[0052] When a photopolymerization initiator is used, the content of the photopolymerization initiator in the composition for light diffusion controlling portion is preferably 0.2 to 20 parts by mass, more preferably 0.5 to 16 parts by mass, particularly preferably 1 to 13 parts by mass, and even more preferably 0.8 to 10 parts by mass, relative to 100 parts by mass of the total amount of the high refractive index component and the low refractive index component. This makes it easy to efficiently form light diffusion controlling portion 2 having the desired regular internal structure.

[0053] (4) Preparation of composition for controlling light diffusion The composition for light diffusion controlling portion can be prepared by uniformly mixing the above-mentioned high refractive index component and low refractive index component, and, if desired, other additives such as a photopolymerization initiator and an ultraviolet absorber.

[0054] During the mixing, a uniform composition for controlling light diffusion may be obtained by stirring while heating to a temperature of 40 to 80° C. Furthermore, a dilution solvent may be added and mixed so that the resulting composition for controlling light diffusion has a desired viscosity.

[0055] (5) Regular internal structure As described above, the light diffusion control film 21 and the single film 2b in the film laminate 2a have a louvered regular internal structure with multiple plate-like regions 201 with a relatively high refractive index within a region 202 with a relatively low refractive index.

[0056] In the light diffusion control film 21 and the single film 2b, it is preferable that each of the plate-like regions 201 is inclined in the first direction D1 within the light diffusion control film 21 and the single film 2b, as shown in Fig. 3. This makes it easier for the aerial image forming device 10 according to this embodiment to suppress the occurrence of ghost images and to display brighter aerial images.

[0057] When the plate-like region 201 is inclined as described above, the angle of inclination relative to the thickness direction of the light diffusion control unit 2 is preferably 0° to 30°, more preferably 1° to 20°, particularly preferably 2° to 15°, and even more preferably 3° to 10°. This makes it easier for the aerial image forming device 10 according to this embodiment to suppress the occurrence of ghost images and to display brighter aerial images.

[0058] The light diffusion control film 21 and the single film 2b may have a structure other than the regular internal structure as shown in Fig. 3. For example, the plate-like region 201 may be bent partway along the thickness direction of the light diffusion control section 2. Here, some of the light diffusion control films 21 constituting the film laminate 2a may have bent plate-like regions 201, and the other light diffusion control films 21 may have unbent plate-like regions 201.

[0059] (6) Thickness of the light diffusion control section When the light diffusion control section 2 is a film laminate 2a, the thickness of the light diffusion control film 21 is preferably 1 to 500 μm, more preferably 10 to 300 μm, particularly preferably 50 to 250 μm, further preferably 80 to 200 μm, and of these, preferably 100 to 160 μm. This makes it easier for the aerial image forming device 10 according to this embodiment to suppress the occurrence of ghost images and to display brighter aerial images.

[0060] When the light diffusion control section 2 is a single film 2b, the thickness of the light diffusion control section 2 is preferably 2 to 1000 μm, more preferably 20 to 600 μm, particularly preferably 100 to 500 μm, further preferably 160 to 400 μm, and of these, preferably 200 to 320 μm. This makes it easier for the aerial image forming device 10 according to this embodiment to suppress the occurrence of ghost images and to display brighter aerial images.

[0061] (7) Method for forming light diffusion control section The method for forming the light diffusion control portions 2 is not particularly limited, and they can be formed by a conventionally known method.

[0062] When the light diffusion control section 2 is a film laminate 2a, first, a required number of light diffusion control films 21 are prepared, and these are laminated to form the film laminate 2a.

[0063] The light diffusion control film 21 can be formed, for example, by applying the above-mentioned composition for light diffusion control portion to one side of a process sheet to form a coating film, and then laminating one side (particularly the release side) of a release sheet to the side of the coating film opposite the process sheet. Subsequently, the coating film is irradiated with active energy rays through the process sheet or the release sheet to cure it, thereby forming the light diffusion control film 21. By laminating the release sheet on the coating film in this way, a gap is maintained between the release sheet and the process sheet, preventing the coating film from being crushed, making it easier to form a light diffusion control film 21 with a uniform thickness and a desired regular internal structure.

[0064] In addition, as a method for forming the single film 2b, for example, the composition for light diffusion control portion described above is applied to one side of a process sheet to form a coating film, and then one side (particularly the release side) of a release sheet is attached to the side of the coating film opposite to the process sheet. Subsequently, the coating film is irradiated with active energy rays through the process sheet or the release sheet to be cured.

[0065] Furthermore, the release sheet is peeled from the laminate of the process sheet, cured film, and release sheet formed as described above, and the composition for light diffusion control section described above is applied to the exposed surface to form a coating film. One side of the release sheet (particularly the release surface) is then laminated to the side of the coating film opposite the process sheet. Subsequently, the coating film is irradiated with active energy rays through the process sheet or the release sheet to cure it, thereby forming a light diffusion control film 2b. By laminating the release sheet on the coating film in this way, a gap between the release sheet and the process sheet is maintained, preventing the coating film from being crushed, making it easier to form a light diffusion control film 2b with a uniform thickness and the desired regular internal structure.

[0066] Examples of the release sheet include resin films such as polyethylene films, polypropylene films, polybutene films, polybutadiene films, polymethylpentene films, polyvinyl chloride films, vinyl chloride copolymer films, polyethylene terephthalate films, polyethylene naphthalate films, polybutylene terephthalate films, polyurethane films, ethylene vinyl acetate films, ionomer resin films, ethylene-(meth)acrylic acid copolymer films, ethylene-(meth)acrylic acid ester copolymer films, polystyrene films, polycarbonate films, polyimide films, and fluororesin films. Crosslinked films of these may also be used. Furthermore, laminated films of these may also be used. From the perspective of the SDGs, the material constituting the release sheet may be a material with a high biomass content, a recyclable or reusable material, or a recycled or reused material.

[0067] The release surface of the release sheet is preferably subjected to a release treatment. Preferred examples of the release agent used for the release treatment include alkyd-based, silicone-based, fluorine-based, unsaturated polyester-based, polyolefin-based, and wax-based release agents.

[0068] The thickness of the release sheet is not particularly limited, but from the viewpoint of excellent handleability and of being able to well protect the light diffusion control part until use, it is preferably 20 to 200 μm, more preferably 30 to 100 μm.

[0069] The process sheet can be the resin film, crosslinked film, or laminated film thereof used as the release sheet described above. The release sheet described above can also be used as the process sheet.

[0070] The thickness of the process sheet is preferably 20 to 250 μm, more preferably 30 to 200 μm, from the viewpoint of facilitating the formation of the desired light diffusion control parts and of being able to adequately protect the light diffusion control parts until use.

[0071] Examples of the coating method include knife coating, roll coating, bar coating, blade coating, die coating, and gravure coating. The composition for light diffusion control portion may be diluted with a solvent as needed.

[0072] The coating film can be irradiated with active energy rays by a conventionally known method. For example, a linear light source is used as a light source of active energy rays, and the surface of the target is irradiated with band-like (almost linear) light that is random in the width direction (TD) and approximately parallel in the flow direction (MD). Note that the inclination angle of the plate-like region 201 can also be adjusted by adjusting the irradiation angle of the light.

[0073] The active energy rays refer to electromagnetic waves or charged particle rays that have an energy quantum, and specific examples include ultraviolet rays, electron beams, etc. Among active energy rays, ultraviolet rays are particularly preferred because they are easy to handle and can easily form a desired regular internal structure.

[0074] When ultraviolet rays are used as the active energy rays, the irradiation conditions are as follows: the peak irradiance on the coating surface is 0.1 to 200 mW / cm 2 Furthermore, it is preferable that the integrated light amount on the coating surface is 5 to 300 mJ / cm. 2 Furthermore, the relative moving speed of the light source of the active energy rays with respect to the irradiation target is preferably 0.1 to 10 m / min.

[0075] From the viewpoint of completing the curing more reliably, it is also preferable to irradiate the cured product with normal active energy rays (active energy rays that have not been converted into parallel light or band-like light, scattered light) after curing using the band-like light as described above.

[0076] 4. Other components The aerial image forming device 10 according to this embodiment may include components other than the above-described display unit 1, light diffusion control unit 2, and translucent imaging unit 3. In particular, the aerial image forming device 10 according to this embodiment preferably includes a housing for fixing and accommodating the display unit 1, light diffusion control unit 2, and translucent imaging unit 3 at predetermined positions.

[0077] The material, shape, dimensions, etc. of the housing can be appropriately selected depending on the application and purpose. In particular, it is preferable that the housing is made of a light-blocking material, which can prevent unintended leakage of light from the display unit 1 to the outside and can prevent unintended intrusion of external light into the optical path from the display unit 1 to the light diffusion control unit 2.

[0078] 5. Positional relationship of each element 3 is assumed to be a first direction indicated by "D1" in Fig. 3, and the second direction is assumed to be a direction parallel to a plane perpendicular to both the display surface of the display unit 1 and one side of the light diffusion control unit 2, and to be a direction existing in the plane of the light diffusion control unit 2 opposite the light-transmitting image formation unit 3. It is preferable that the acute angle formed by the first direction and the second direction is between 0° and 90°. Regardless of the angle of the acute angle, by considering the angle of incidence to the light diffusion control unit 2 in a plane that includes D1 and is perpendicular to the light diffusion control unit 2, the aerial image forming device 10 according to this embodiment can more easily suppress the occurrence of ghost images and more easily display brighter aerial images.

[0079] Furthermore, when the aerial image forming device 10 according to this embodiment is equipped with the aforementioned retrotransmissive optical element having a two-sided corner reflector array structure as the light-transmitting imaging unit 3, or a retrotransmissive optical element consisting of two layers each having multiple reflective surfaces stacked together, it is also preferable that the following conditions be satisfied.

[0080] First, assume a plane F that is perpendicular to both the surface of the translucent imaging unit 3 opposite the light diffusion control unit 2 and the display surface of the display unit 1 and that passes through the center point of the translucent imaging unit 3. Also, the width of the translucent imaging unit 3 in a cross section obtained by cutting the translucent imaging unit 3 at the plane F is defined as width W.

[0081] Furthermore, an observation point is assumed to exist within the plane F and to satisfy both the following conditions A and B. (Condition A) If the angle between the line segment connecting the observation point and the center point and the surface opposite the light diffusion control unit 2 in the light-transmitting imaging unit 3 is defined as angle α, and the angle between the plane including the display surface of the display unit 1 and the plane including the surface opposite the light diffusion control unit 2 in the light-transmitting imaging unit 3 is defined as angle β, the sum of angle α and angle β is 90°. (Condition B) The distance between the observation point and the center point is 1 to 10 times the width W.

[0082] As a supplementary note, the above condition A means that the position of the observation point is determined depending on the positional relationship between the display unit 1 and the light-transmitting imaging unit 3 in the aerial image forming device 10. For example, for an aerial image forming device 10 in which the display unit 1 and the light-transmitting imaging unit 3 are arranged so that the angle β is 45°, the angle α related to the observation point is 45°, and for an aerial image forming device 10 in which the angle β is 60°, the angle α related to the observation point is 30°.

[0083] Regarding the above condition B, the expression "1 to 10 times the width W" means that the observation point only needs to satisfy the condition of any one point within this range. In particular, it is preferable that condition B is "the distance between the observation point and the center point is 3.5 times the width W."

[0084] It is preferable that each element of the aerial image forming device 10 is configured so that the light diffusion control unit 2 simultaneously satisfies the following two conditions when the aerial image forming device 10 is observed from the observation point. (Condition 1) Of the light that is irradiated from any one point on the display unit 1 and reaches the observation point, the haze value for the light that is reflected by both of the two layers that make up the retrotransmitting optical element is 60% or less. (Condition 2) Of the light that is irradiated from any one point on the display unit 1 and reaches the observation point, the haze value for light that is reflected by only one of the two layers that make up the retrotransmitting optical element is 60% or more.

[0085] When the aerial image forming device 10 according to this embodiment satisfies the above conditions, it becomes easier to suppress the occurrence of ghost images and to display brighter aerial images.

[0086] Here, "reflection occurs in both layers" or "reflection occurs in only one of the two layers" does not refer to physical reflection, but rather to reflection in the sense of changing the direction of travel. Since parallel mirror surfaces are arranged in each layer of a retrotransmissive optical element, which is made up of two layers stacked together, each layer having multiple reflective surfaces, the direction of travel is changed by an odd number of reflections, but not by an even number of reflections. The phrase "reflection occurs" in the above can be rephrased as "reflection occurs an odd number of times, and the direction of travel is changed."

[0087] 6. Manufacturing method of aerial image forming device There are no particular limitations on the method for manufacturing the aerial image forming device 10 according to this embodiment. For example, after preparing the display unit 1, the light diffusion control unit 2, and the light-transmitting image forming unit 3, the display unit 1 is placed at a predetermined position on the housing, and a laminate of the light diffusion control unit 2 and the light-transmitting image forming unit 3 is placed, thereby obtaining the aerial image forming device 10.

[0088] 7. How to use the aerial image formation device The aerial image forming device 10 according to this embodiment can be used as a display device for displaying any image or video in the air. There are no specific limitations on how it can be used, and it can be used in the same way as a conventionally known display device.

[0089] [Laminate] The laminate according to this embodiment is the aerial image forming device 10 described above with the display unit 1 omitted. That is, the laminate according to this embodiment includes a light-transmitting imaging unit 3 that causes light incident from one surface to form an image at a position on the other surface, and a light diffusion control unit 2 laminated on one surface of the light-transmitting imaging unit 3. Details of the composition, structure, etc. of the light-transmitting imaging unit 3 and the light diffusion control unit 2 are as described above.

[0090] The laminate according to this embodiment can be obtained by preparing a light-transmitting imaging unit 3 and a light diffusion control unit 2 and then laminating them together. The laminate according to this embodiment can also be used to form an aerial image forming device 10 according to this embodiment. That is, the aerial image forming device 10 according to this embodiment can be obtained by placing a display unit 1 at a predetermined position on the laminate according to this embodiment.

[0091] In this specification, when it is written "X to Y" (X and Y are any numbers), it means "X or more and Y or less" unless otherwise specified, and also includes the meaning "preferably greater than X" or "preferably smaller than Y." Furthermore, when it is written "X or more" (X is any number), it means "preferably greater than X" unless otherwise specified, and when it is written "Y or less" (Y is any number), it also means "preferably smaller than Y" unless otherwise specified.

[0092] The above-described embodiments have been described to facilitate understanding of the present invention, and are not intended to limit the present invention. Therefore, each element disclosed in the above embodiments is intended to include all design modifications and equivalents that fall within the technical scope of the present invention. [Example]

[0093] The present invention will be explained in more detail below with reference to examples, but the scope of the present invention is not limited to these examples.

[0094] [Production Example 1] (Light diffusion control film A) (5° tilt, no bending) 1. Preparation of composition for light diffusion control film To 40 parts by mass (solids equivalent; same below) of polyether urethane methacrylate having a weight average molecular weight of 9,900 obtained by reacting polypropylene glycol, isophorone diisocyanate, and 2-hydroxyethyl methacrylate as a low refractive index component, 60 parts by mass of o-phenylphenoxyethoxyethyl acrylate having a molecular weight of 268 as a high refractive index component and 8 parts by mass of 2-hydroxy-2-methyl-1-phenylpropan-1-one as a photopolymerization initiator were added, and the mixture was heated and mixed at 80°C to obtain a composition for light diffusion control films.

[0095] Here, the weight average molecular weight (Mw) is a weight average molecular weight measured using gel permeation chromatography (GPC) under the following conditions (GPC measurement) and converted into standard polystyrene. <Measurement conditions> Measurement equipment: Tosoh HLC-8320 GPC columns (passed in the following order): Tosoh Corporation TSK gel superH-H TSK gel super HM-H TSK gel superH2000 Measurement solvent: tetrahydrofuran ·Measurement temperature: 40℃

[0096] 2. Formation of light diffusion control film The obtained composition for a light diffusion control film was applied to the release surface of a release sheet S1 (thickness: 188 μm) made by treating one side of a polyethylene terephthalate film with a silicone-based release agent as a processing sheet, to form a coating film. This resulted in a laminate consisting of the coating film and the processing sheet. Next, the release surface of a release sheet S2 (thickness: 38 μm) made by treating one side of a polyethylene terephthalate film with a silicone-based release agent was laminated on the coating film side of the laminate, resulting in a laminate consisting of the processing sheet, the coating film, and the release sheet S2 laminated in this order.

[0097] The resulting laminate was then placed on a conveyor. The release sheet S2 of the laminate was placed on top, and the longitudinal direction of the process sheet and release sheet S2 was parallel to the conveyor flow direction. An ultraviolet irradiation device (manufactured by Eye Graphics, product name "ECS-4011GX") equipped with a linear high-pressure mercury lamp and a cold mirror for focusing was then installed in front of the conveyor on which the laminate was placed. This device can irradiate a single point on the target with scattered ultraviolet light in a band shape (almost linear). The ultraviolet irradiation device was installed so that the longitudinal direction of the high-pressure mercury lamp was perpendicular to the conveyor flow direction.

[0098] Furthermore, when viewed from the longitudinal direction of the high-pressure mercury lamp, the irradiation angle of the ultraviolet light irradiated from the high-pressure mercury lamp to the laminate was set to -5° with respect to the normal to the laminate surface. Note that the irradiation angle here refers to the acute angle formed by the normal to the laminate surface and the ultraviolet light, expressed as a plus sign, when the ultraviolet light is irradiated toward the downstream side of the conveyor flow, with respect to the position directly below the high-pressure mercury lamp on the laminate, and the acute angle formed by the normal to the laminate surface and the ultraviolet light, expressed as a minus sign, when the ultraviolet light is irradiated toward the upstream side of the conveyor flow.

[0099] Thereafter, the conveyor was operated to move the laminate at a speed of 1.0 m / min, while applying a peak irradiance of 2.5 mW / cm 2 to the coating surface. 2 , cumulative light intensity 40.0mJ / cm 2 The coating film in the laminate was cured by irradiating it with ultraviolet light through the release sheet under the conditions (this curing is sometimes referred to as "primary curing" for convenience).

[0100] Subsequently, while moving at a speed of 1.0 m / min, a peak irradiance of 190 mW / cm 2 was applied to the coating film via the release sheet S2. 2 , cumulative light intensity 180mJ / cm 2The coating film in the laminate was cured by irradiating it with ultraviolet light (scattered light) under the conditions (this curing is sometimes referred to as "secondary curing" for convenience). The peak irradiance and cumulative light amount mentioned above were measured by placing a UV meter (manufactured by Eye Graphics, product name "Eye Ultraviolet Integrating Illuminance Meter UVPF-A1") equipped with a photodetector at the position of the coating film.

[0101] Through the above primary curing and secondary curing, the above-mentioned coating film was sufficiently cured to form a light diffusion control film A. This resulted in a laminate comprising the process sheet, the light diffusion control film A having a thickness of 140 μm, and the release sheet S2 laminated in this order.

[0102] Furthermore, when the cross section of the formed light diffusion control film A was observed using a microscope, it was confirmed that a louver structure in which multiple plate-like regions 201 were arranged in parallel at predetermined intervals was formed inside the light diffusion control film A, as shown in Figure 3. The acute angle between the main surface of the louver structure and the normal to the light diffusion control film A was approximately 3°.

[0103] [Production Example 2] (Light diffusion control film B) (10° tilt, bent) To 40 parts by mass (solids equivalent; same below) of polyether urethane methacrylate with a weight average molecular weight of 9,900 obtained by reacting polypropylene glycol, isophorone diisocyanate, and 2-hydroxyethyl methacrylate as a low refractive index component, 60 parts by mass of o-phenylphenoxyethoxyethyl acrylate with a molecular weight of 268 as a high refractive index component, 8 parts by mass of 2-hydroxy-2-methyl-1-phenylpropan-1-one as a photopolymerization initiator, 0.5 parts by mass of an acrylic leveling agent (manufactured by BYK Japan, product name "BYK-361N"), and 0.08 parts by mass of a benzotriazole compound as an ultraviolet absorber (manufactured by BASF, product name "Tinuvin 384-2") were added, and the mixture was heated and mixed at 80°C to obtain a composition for light diffusion control films.

[0104] A laminate including a light diffusion control film B was obtained in the same manner as in Production Example 1, except that the composition for a light diffusion control film obtained as described above was used and the irradiation angle of ultraviolet light was changed to -10°.

[0105] Furthermore, when the cross section of the formed light diffusion control film B was observed under a microscope, it was confirmed that a plurality of plate-like regions 201 were arranged in parallel at predetermined intervals inside the light diffusion control film B, forming a louver structure bent in the film thickness direction. The acute angle formed by the main surface of the louver structure and the normal to the light diffusion control film B was approximately 7°.

[0106] [Production Example 3] (Light diffusion control film C) (5° tilt, bent) To 40 parts by mass (solids equivalent; same below) of polyether urethane methacrylate with a weight average molecular weight of 9,900 obtained by reacting polypropylene glycol, isophorone diisocyanate, and 2-hydroxyethyl methacrylate as a low refractive index component, 60 parts by mass of o-phenylphenoxyethoxyethyl acrylate with a molecular weight of 268 as a high refractive index component, 8 parts by mass of 2-hydroxy-2-methyl-1-phenylpropan-1-one as a photopolymerization initiator, 0.5 parts by mass of an acrylic leveling agent (manufactured by BYK Japan, product name "BYK-361N"), and 0.08 parts by mass of a benzotriazole compound as an ultraviolet absorber (manufactured by BASF, product name "Tinuvin 384-2") were added, and the mixture was heated and mixed at 80°C to obtain a composition for light diffusion control films.

[0107] A laminate including a light diffusion control film C was obtained in the same manner as in Production Example 1, except that the composition for a light diffusion control film obtained as described above was used and the irradiation angle of ultraviolet light was changed to -5°.

[0108] Furthermore, when the cross section of the formed light diffusion control film C was observed under a microscope, it was confirmed that a plurality of plate-like regions 201 were arranged in parallel at predetermined intervals inside the light diffusion control film C, forming a louver structure bent in the film thickness direction. The acute angle formed by the main surface of the louver structure and the normal to the light diffusion control film C was approximately 3°.

[0109] [Example 1] (Aerial image forming device) The process sheet was peeled off from the laminate obtained in Manufacturing Example 1, and the exposed surface of the light diffusion control film A was laminated to one side of a retrotransmitting optical element (manufactured by Asukanet Co., Ltd., product name "ASKA3D-200NT", length 200 mm x width 200 mm x thickness 6.3 mm) consisting of two layers with multiple reflective surfaces laminated together, as a translucent imaging section, via a 25 μm acrylic transparent adhesive.

[0110] Furthermore, the process sheet was peeled off from the laminate obtained in Production Example 2, and the exposed surface of the light diffusion control film B thus exposed was laminated, via a 25 μm acrylic transparent adhesive, to the surface of the laminate of the light diffusion control film A and the translucent image forming portion obtained as described above, from which the release sheet on the light diffusion control film A side had been peeled off. At this time, the light diffusion control film A and the light diffusion control film B were laminated so that the first direction (a direction perpendicular to the longitudinal direction of the plate-like region and present in the plane opposite the translucent image forming portion in the light diffusion control portion (light diffusion control film); D1 in FIG. 3) coincided, and the multiple plate-like regions 201 were tilted in opposite directions. This resulted in a laminate comprising a light diffusion control portion formed by laminating the light diffusion control film B and the light diffusion control film A, and a translucent image forming portion laminated on the surface of the light diffusion control portion facing the light diffusion control film A.

[0111] The obtained laminate of the light diffusion control section and the light-transmitting image forming section was then placed in a predetermined housing so that the main surface of the laminate was horizontal and the surface on the light diffusion control section side was facing downward. Furthermore, as a display section, a laptop computer screen was placed in the housing so that it faced the laminate of the light diffusion control section and the light-transmitting image forming section, and so that the multiple plate-like regions 201 of diffusion film A were inclined toward the display section, and the multiple plate-like regions 201 of diffusion film B were inclined in the direction opposite to the display section.

[0112] When the display unit was installed, the angle between the display surface of the display unit 1 and the main surface of the light diffusion control unit 2 was 45°, as shown in Fig. 5(a). The display unit was also installed so that the angle between the first direction and the second direction (a direction parallel to a plane perpendicular to both the display surface and one side of the light diffusion control unit, and a direction existing in the plane opposite the translucent image forming unit in the light diffusion control unit) was 0°. The display unit was also installed so that the distance between the center of the display surface of the display unit 1 and the center of the main surface of the light diffusion control unit 2 was 700 mm.

[0113] The housing is light-shielding so that light emitted from the display unit does not escape to the outside from any part other than the light diffusion control unit and the light-transmitting image forming unit.

[0114] As a result of the above, an aerial image forming device 10 was obtained in which the light-transmitting image forming unit 3, the light diffusion control unit 2, and the display unit 1 were arranged in a housing, as shown in FIG. 5(a).

[0115] Comparative Example 1 The process sheet was peeled off from the laminate obtained in Production Example 3, and the exposed surface of the light diffusion control film C thus exposed was laminated, via a 25 μm acrylic transparent adhesive, to one side of a retrotransmitting optical element (manufactured by Asukanet Co., Ltd., product name "ASKA3D-200NT", length 200 mm × width 200 mm × thickness 6.3 mm) consisting of two layers with multiple reflective surfaces as a translucent imaging unit. An aerial image forming device was obtained in the same manner as in Example 1, except that the resulting laminate of the light diffusion control unit (single layer of light diffusion control film C) and the translucent imaging unit was installed in a housing so that the multiple plate-shaped regions 201 of the diffusion film C were tilted in the direction opposite to the display unit.

[0116] Comparative Example 2 Except for not using the light diffusion control unit, an aerial image forming device was obtained in the same manner as in Example 1. That is, as shown in Fig. 5(b), an aerial image forming device was obtained in which a light-transmitting imaging unit 3 and a display unit 1 were arranged in a housing.

[0117] [Test Example 1] (Measurement of variable angle haze) For each of the light diffusion control films A to C produced in Production Examples 1 to 3, the haze value (%) was measured using a variable angle haze meter (manufactured by Toyo Seiki Seisaku-sho, product name "Haze Guard Plus, variable angle haze meter").

[0118] Specifically, one side of the light diffusion control film was irradiated with light while changing the angle of incidence relative to the normal to the film in the first direction (D1 in Figure 3) from -90° to 90°, and the haze value (%) was measured sequentially. The results are shown in Figures 6(a) to 6(c). In these figures, the vertical axis represents the haze value (%) and the horizontal axis represents the angle of incidence (°), and the curved line in the graph shows the change in haze value as the angle of incidence changes.

[0119] [Test Example 2] (Evaluation of ghost image reduction and white haze suppression) For the aerial image forming devices manufactured in the example and comparative example, an image measuring 70 mm in height and 100 mm in width was displayed on the display unit to generate an aerial image, which was then visually observed.

[0120] As a result, in Comparative Example 2, ghost images were clearly generated on the left and right sides of the aerial image, whereas in Example 1 and Comparative Example 1, the generation of ghost images was reduced to a level that was almost unnoticeable. Furthermore, compared to Comparative Example 1, in Example 1, the haze was less noticeable. [Industrial Applicability]

[0121] The aerial image forming device of the present invention can be suitably used as a display or the like that displays an aerial image. [Explanation of symbols]

[0122] 10...Aerial image forming device 1...Display section 2...Light diffusion control section 2a...Film laminate 21...Light diffusion control film 2b...Single film 201...Plate region 202: Area with relatively low refractive index 3... Translucent imaging section 4...Aerial image observation surface 5...Observation point

Claims

1. a display unit having a display surface and emitting light from the display surface; a light diffusion control unit disposed on the display surface side of the display unit and diffusing or transmitting the light depending on the incident angle of the light; a light-transmitting image forming section that is laminated on a surface of the light diffusion control section opposite to the display section, transmits the light that has passed through the light diffusion control section, and forms an image at a position on the surface opposite to the light diffusion control section; Equipped with The light diffusion control section A film laminate comprising at least two films laminated together, each having a louvered regular internal structure with a plurality of plate-like regions having a relatively high refractive index within a region having a relatively low refractive index, or It is a single film consisting of at least two layers of a louver-like regular internal structure with multiple plate-like regions with a relatively high refractive index in a region with a relatively low refractive index. An aerial image forming device characterized by:

2. The aerial image forming device of claim 1, characterized in that the display unit is positioned relative to the light diffusion control unit and the light-transmitting image forming unit so that the display surface and the surface of the light diffusion control unit opposite the light-transmitting image forming unit are non-parallel.

3. For at least one of the ordered internal structures within the film stack or within the single film: When a direction perpendicular to the longitudinal direction of the plate-like region and existing in a plane of the light diffusion control unit on the opposite side to the light-transmitting image forming unit is defined as a first direction, Each of the plate-like regions is inclined toward the first direction within the light diffusion control section.

2. The aerial image forming apparatus according to claim 1.

4. 2. The aerial image forming device according to claim 1, wherein the light-transmitting imaging unit includes a retrotransmitting optical element that retrotransmits incident light.

5. The retrotransmitting optical element is formed by stacking two layers each having a plurality of reflecting surfaces, In each of the two layers, the plurality of reflective surfaces are arranged perpendicular to one surface of the retrotransmissive optical element and at predetermined intervals from each other, The two layers are laminated so that the reflecting surface of one layer is perpendicular to the reflecting surface of the other layer.

5. The aerial image forming apparatus according to claim 4.

6. a light-transmitting imaging unit that causes light incident from one surface to form an image at a position on the other surface side; a light diffusion control section laminated on one side of the light-transmitting imaging section; Equipped with the light diffusion control section diffuses or transmits light incident thereon depending on the angle of incidence, The light diffusion control section A film laminate comprising at least two films laminated together, each having a louvered regular internal structure with a plurality of plate-like regions having a relatively high refractive index within a region having a relatively low refractive index, or It is a single film consisting of at least two layers of a louver-like regular internal structure with multiple plate-like regions with a relatively high refractive index in a region with a relatively low refractive index. A laminate characterized by:

Images