System for projection onto a projection screen having a dark part and a transparent part

Abstract

One aspect of the invention relates to a projection system (1) comprising: - a projector (11); - a diffuse-reflection projection screen (12) having a dark part (12b) and a transparent part (12a), said projector (11) being positioned opposite the projection screen (12) such that a light beam (111) emitted by the projector (11) covers both the dark part (12b) and the transparent part (12a) of the projection screen (12).

Description

DESCRIPTION TITLE: Projection system on a projection screen comprising a dark part and a transparent part TECHNICAL FIELD OF THE INVENTION

[0001] The technical field of the invention is that of the projection of information for use in interior partitions in public transport (trains, buses, metros, trams, etc.) and more generally for any type of partition whatever the field (building, museums, commercial premises, etc.).

[0002] The present invention relates to a projection system, a projection method and methods of manufacture. TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0003] In certain locations such as train stations or airports, or in certain vehicles such as trains or airplanes, the display of important information intended for passengers, such as train / airplane arrival times and destination, requires specific contrast.

[0004] In trains, for example, train stations or airports, the display devices on which information can be projected are transparent glazing with diffuse reflection, for example, which does not provide the specific contrast necessary for good viewing of the information. Usually, reflection by a glazing is said to be diffuse when radiation incident on the glazing with a given angle of incidence is reflected by the glazing in a plurality of directions. Reflection by a glazing is said to be specular when radiation incident on the glazing with a given angle of incidence is reflected by the glazing with an angle of reflection equal to the angle of incidence. By analogy, transmission through a glazing is said to be specular when radiation incident on the glazing with a given angle of incidence is transmitted by the glazing with an angle of transmission equal to the angle of incidence.

[0005] One solution to achieve a higher specific contrast than with transparent glazing is the use of black or dark glazing onto which information can be projected, the glazing using absorbent layers, for example, to increase its contrast.

[0006] However, transport regulations require that the projection screens used, or in other words, the glazing, have a large transparent area - in order to be able to see through the glazing - and, as far as possible, respect a usual aspect ratio (4:3, 16:9 or 16:10). The extent of the dark area must therefore be relatively limited.

[0007] In view of these technical and regulatory constraints, a person skilled in the art is naturally encouraged to implement a projector having either a screen area with a usual aspect ratio but whose surface area is reduced so that it can be contained in the dark area or a screen area with an aspect ratio adapted to the extent of the dark area.

[0008] Such technical solutions, although partially satisfactory, have significant drawbacks, such as the reduction of the screen area or the specific adaptation of digital content and the projector to screen areas with an unusual aspect ratio.

[0009] There is a need to improve such state-of-the-art solutions. SUMMARY OF THE INVENTION

[0010] The invention provides a solution to the problems mentioned above, by making it possible to display content with better contrast than the information displays cited in the state of the art.

[0011] A first aspect of the invention relates to a projection system comprising: a projector; a diffusely reflective projection screen comprising a dark portion and a transparent portion; said projector being positioned opposite the projection screen so that a light beam emitted by the projector covers both the dark portion and the transparent portion of the projection screen.

[0012] By means of the invention, it is possible to project the light beam of the projector onto a larger dark area, while maintaining a usual aspect ratio (4:3, 16:9 or 16:10), and without the need for specific adaptation of the projector. It is further possible to project a light beam, comprising content such as written information or images, onto both the dark part and on the transparent part and to observe a selective contrast depending on the sensitivity of the projected content, the use of the dark part allowing to obtain a better contrast of the information displayed compared to the transparent screen. Note that the transparent and dark parts allow projection of information thanks to the diffuse reflection properties of the projection screen. By projecting a light beam on both the transparent part and the dark part of the screen, the regulations are respected and the contrast of the information displayed (included in the light beam) is improved. In addition, a single projector is sufficient to display information on both the transparent part and the dark part of the screen. A projection system according to the invention is therefore easier to integrate into a vehicle or a building.

[0013] It is understood that the diffuse reflection projection screen is a passive device, that is to say in particular that the appearance of the diffuse reflection projection screen itself is not modified by an external energy source, for example electrical. The diffuse reflection projection screen therefore has the same appearance whether an image is projected on it or not, apart from the formation of the projected image by the projector.

[0014] It is therefore understood that the dark part and the transparent part of the diffuse reflection projection screen are static parts whose respective areas cannot be modified.

[0015] In addition to the characteristics which have just been mentioned in the preceding paragraph, the projection system according to the first aspect of the invention may have one or more additional characteristics among the following, considered individually or according to all technically possible combinations: An intensity of the light beam received by the dark part of the projection screen is different from an intensity of the light beam received by the transparent part of the projection screen. The dark part has an area substantially equal to or different from a transparent part area. The projection screen is a layered element comprising: a lower substrate comprising a smooth upper surface and a smooth lower surface; an absorbing layer extending along a portion of the lower substrate; a lower layer made of dielectric materials, said lower layer being arranged above the lower substrate; an upper layer made of dielectric materials, the lower layer and the upper layer having substantially identical refractive indices;a central layer interposed between the lower layer and the upper layer, this central layer being formed either by a single layer which is a dielectric layer with a refractive index different from that of the external layers or a metallic layer, or by a stack of layers which comprises at least one dielectric layer with a refractive index different from that of the external layers or a metallic layer, where each contact surface between two adjacent layers of the projection screen which are one dielectric and the other metallic, or which are two dielectric layers with different refractive indices, is textured and parallel to the other textured contact surfaces between two adjacent layers which are one dielectric and the other metallic or which are two dielectric layers with different refractive indices.; The projection screen includes a first outer surface and a second outer surface, and the projector faces the outer surface of the projection screen furthest from the absorbing layer among the first outer surface and the second outer surface. The top layer is a glass substrate comprising a smooth top surface and a textured bottom surface, the textured bottom surface being in contact with the core layer. According to one embodiment: the first outer surface of the projection screen is the upper surface of the upper layer; the second outer surface of the projection screen is the lower surface of the lower substrate; and the outer surface furthest from the absorbent layer is the first outer surface. The projection screen comprises an outer substrate in contact with the outer layer and comprises an intermediate layer, preferably made of a polymer material, the assembly formed by the upper layer, the central layer, the lower layer and the intermediate layer being comprised between the lower substrate and the upper substrate.

[0016] According to one embodiment: the first outer surface of the projection screen is the upper surface of the upper substrate; the second outer surface of the projection screen is the lower surface of the lower substrate; and the outer surface furthest from the absorbing layer is the first outer surface. The lower substrate is glass. The lower substrate is transparent. The lower substrate is absorbent.

[0017] Another aspect of the invention relates to a projection method implemented by the projection system according to the invention comprising a step of positioning the projector opposite the screen and a step of projecting a light beam covering both the transparent part and the dark part of the projection screen.

[0018] Another aspect of the invention relates to a method for manufacturing a projection system according to the invention, the method comprising the following steps: obtaining a first substrate, preferably made of glass, comprising a first smooth main surface and a second smooth main surface opposite each other, said substrate forming the lower substrate, the first smooth main surface being the lower surface of the lower substrate and the second main surface being the upper surface of the lower substrate; depositing, preferably by screen printing, the absorbent layer on the lower substrate, the absorbent layer extending along a portion of the lower substrate; obtaining a second substrate, preferably made of glass, comprising a smooth main surface and a textured main surface, said second substrate forming the upper layer, said smooth main surface being the upper surface of the upper layer and said textured surface being the lower surface of the upper layer; deposition, preferably by magnetron and / or screen printing, of a conformal layer on the upper layer and in particular on the lower, textured surface of the upper layer, said conformal layer forming the central layer; assembly by lamination of the assembly formed by the upper layer and the central layer with the lower substrate, the assembly being carried out via an interlayer, preferably made of polymer, adapted to deform in order to match a textured surface of the central layer, the interlayer forming the lower layer.

[0019] Another aspect of the invention relates to a method for manufacturing a projection system according to the invention, the method comprising the following steps: obtaining a first substrate, preferably made of glass, comprising a first smooth main surface and a second smooth main surface opposite each other, said first substrate forming the lower substrate, the first smooth main surface being the lower surface of the lower substrate and the second main surface being the upper surface of the lower substrate; depositing, preferably by screen printing, the absorbent layer on the lower substrate, the absorbent layer extending along a portion of the lower substrate;obtaining a second substrate, preferably made of glass, comprising a first smooth main surface and a second smooth main surface, said second substrate forming the upper substrate, said first smooth main surface being the upper surface of the upper substrate, and said second smooth main surface being the lower surface of the upper substrate; obtaining a third substrate, preferably in the form of a plastic film, comprising a smooth main surface and a textured main surface, said smooth main surface being the lower surface of the; lower layer and said textured surface being the upper surface of the lower layer; deposition, preferably by magnetron and / or screen printing, of a conformal layer on the lower layer and in particular on the textured upper surface of the lower layer, said conformal layer forming the central layer; assembly by lamination of the lower substrate with the assembly formed by the lower layer and the central layer, the assembly being carried out via the intermediate layer; assembly by lamination of the upper substrate with the assembly formed by the lower layer, the central layer, the intermediate layer and the lower substrate, the assembly being carried out via the upper layer which is adapted to deform in order to match a textured surface of the central layer.

[0020] The invention and its various applications will be better understood by reading the following description and examining the accompanying figures. BRIEF DESCRIPTION OF THE FIGURES

[0021] The figures are presented for information purposes only and in no way limit the invention. [Fig. 1] shows a schematic representation of a projection system according to a first aspect of the invention. [Fig. 2] shows a schematic representation of one embodiment of the projection screen included in the projection system. [Fig. 3] shows a schematic representation of a variant of [Fig. 2]. [Fig. 4] shows a schematic representation representing the transparent and dark parts of the screen according to the embodiment of [Fig. 1]. [Fig. 5] shows a schematic representation of a second embodiment of the projection screen included in the projection system. [Fig. 6] shows a schematic representation of a variant of [Fig. 5] [Fig. 7] shows a schematic representation representing the transparent and dark parts of the screen according to the embodiment of [Fig. 5]. [Fig. 8] is a block diagram of a projection method implemented by the projection system according to the invention. [Fig. 9] is a block diagram of a method of manufacturing the projection screen of the system according to the invention according to a first embodiment. [Fig. 10] is a block diagram of a method of manufacturing the projection screen of the system according to the invention according to a second embodiment. DETAILED DESCRIPTION

[0022] Unless otherwise specified, the same element appearing in different figures has a single reference.

[0023] A first aspect of the invention relates to a projection system comprising a projector and a diffusely reflective projection screen comprising a dark portion and a transparent portion. According to the invention, the projector is positioned so as to emit a light beam covering both the dark portion of the screen and the transparent portion of the screen, the dark portion being opposite said projector and the transparent portion being opposite the projector as well.

[0024] The projector is positioned so as to emit a beam that completely or partially covers the dark part, and completely or partially covers the transparent part at the same time.

[0025] The transparent part of the projection screen forms a transparent screen, and the dark part of the projection screen forms a dark screen.

[0026] According to the invention, a transparent element is an element through which there is a transmission of radiation at least in the wavelength ranges useful for the intended application of the element. In the context of the invention, each layered element is transparent at least in the visible wavelength range. In particular, the transmission of radiation through said element is preferably specular.

[0027] [Fig. 1] shows a schematic representation of the projection system 1 according to the invention.

[0028] The projection system 1 comprises the projector 11 and the projection screen 12.

[0029] Preferably, the projector 11 is a video projector.

[0030] Thus, the projector 11 is positioned so as to be opposite the diffuse reflection projection screen 12.

[0031] The projection screen 12 comprises a transparent portion 12a and a dark portion 12b.

[0032] The transparent part 12a and the dark part 12b are both opposite the projector 11.

[0033] The projector 11 is positioned so as to emit at least one light beam 111 covering both the transparent part 12a and the dark part 12b.

[0034] In particular, the beam 111 emitted by the projector makes it possible to display content on the projection screen 12, said content possibly comprising a first sub-content projected onto the transparent portion 12a and a second sub-content projected onto the dark portion 12b. Thus, a first portion of the light beam covers the transparent portion 12a and a second portion of the beam covers the dark portion 12b. For example, the light intensity of the portion of the light beam received by the transparent portion 12a differs from the light intensity of the portion of the light beam received by the dark portion 12b.

[0035] An area of ​​the transparent portion 12a may be substantially equal to or different from an area of ​​the dark portion 12b.

[0036] The area of ​​the transparent portion 12a may be less than or greater than the area of ​​the dark portion 12b.

[0037] In particular, the projection screen 12 is a layered element.

[0038] Throughout the description, a projection screen according to the invention is considered to be placed horizontally, with a first face facing downwards defining a lower external surface and a second face, opposite the first face, facing upwards defining an upper external surface. The meanings of the expressions "above" and "below" are thus to be considered in relation to this orientation. The terms "lower" and "upper" are also used herein with reference to this positioning.

[0039] The screen 12 includes a lower substrate, a lower layer deposited on the lower substrate, a top layer and a middle layer interposed between the top layer and the bottom layer, and an absorbent layer extending along a portion of the lower substrate.

[0040] The screen 12 includes a first outer surface and a second outer surface.

[0041] The projector 11 is positioned so as to be opposite the outer surface, among the first outer surface and the second outer surface, the furthest from the absorbent layer. A portion of the incident beam is thus reflected diffusely, before it can reach the absorbent layer.

[0042] The lower substrate, the bottom layer, the core layer and the absorbent layer are arranged in parallel.

[0043] The lower substrate comprises a smooth upper surface and a smooth lower surface.

[0044] A smooth surface (respectively interface) is a surface (respectively interface) for which the surface (respectively interface) irregularities are smaller than the wavelength of the radiation incident on the surface / interface, so that the radiation is not deflected by these surface (respectively interface) irregularities. The incident radiation is then transmitted and reflected specularly by the surface / interface.

[0045] The lower substrate is preferably made of glass (mineral) and is preferably transparent.

[0046] The lower substrate may also be made of a polymeric material. Examples of suitable transparent polymers for the lower substrate include, but are not limited to, polycarbonate and PMMA (an acronym for "polymethyl methacrylate").

[0047] An example of a glass substrate that can be used directly as a lower substrate is the glass substrate marketed by Saint-Gobain Glass in the PARSOL ULTRA GREY VENUS range (VG10, VG20, VG40).

[0048] In particular, the lower substrate may be entirely transparent or absorbent and transparent.

[0049] There is no limitation on the dimensions of the lower substrate. For example, the lower substrate 121 may have a thickness of between 1.1 mm and 12 mm, more particularly between 1.6 mm and 6 mm, even more particularly between 1.6 mm and 2.6 mm, or even for example substantially equal to, or equal to, 2 mm.

[0050] The lower layer is formed of at least one electrical material.

[0051] The top layer is formed of at least one dielectric material.

[0052] The dielectric material forming the lower layer has a refractive index substantially equal to the dielectric material forming the upper layer.

[0053] Two dielectric materials have their refractive indices substantially equal, when the absolute value of the difference between their refractive indices at 550 nm is less than or equal to 0.15. Preferably, the absolute value of the difference in refractive index at 550 nm between the respective dielectric materials of the two outer layers of the layered element is less than 0.05, more preferably less than 0.015.

[0054] According to one embodiment, the central layer comprises a single layer formed of a dielectric material with a refractive index different from the refractive index of the dielectric material forming the lower layer (and consequently different from the refractive index of the dielectric material forming the upper layer).

[0055] According to one embodiment, the central layer is formed by a stack of layers, the stack of layers comprising at least one layer formed from a dielectric material with a refractive index different from that of the dielectric material of the first outer layer and that of the dielectric material of the second outer layer.

[0056] According to one embodiment, the central layer comprises a single metallic layer.

[0057] According to one embodiment, the central layer is formed by a stack of layers, the stack of layers comprising at least one metal layer.

[0058] The core layer includes a first textured surface and a second textured surface.

[0059] In particular, the contact surface between two adjacent layers of the layered element which are one dielectric and the other metallic, or which are two dielectric layers of different refractive indices, is textured and parallel to the other textured contact surfaces between two adjacent layers which are one dielectric the other metallic or which are two dielectric layers of different refractive indices.

[0060] A textured surface of a substrate is a surface for which the surface properties vary on a scale larger than the wavelength of the radiation incident on the surface. The incident radiation is then transmitted and reflected diffusely by the surface. The texturing of a surface can be obtained by any known texturing method, for example by embossing the surface of the substrate previously heated to a temperature at which it is possible to deform it, in particular by rolling by means of a roller having on its surface a texturing complementary to the texturing to be formed on the substrate; by abrasion by means of abrasive particles or surfaces, in particular by sandblasting; by chemical treatment, in particular acid treatment in the case of a glass substrate; by molding, in particular injection molding in the case of a thermoplastic polymer substrate, by etching.

[0061] Preferably, the absorbent layer is dark or black. The absorbent layer may be a dark enamel, for example a black enamel, or a dark paint, for example a black paint.

[0062] An element is said to be dark if it has a black luminance of less than 30 cd / m 2in an environment illuminated at 350 LUX measured along the preferred diffusion direction. The "dark" color can also be evaluated using the colorimetric coordinates L*, a* and b* calculated by taking into account the illuminant D65 and the CIE-1931 reference observer. The L* component defines the lightness, which ranges from the value 0 for black to the value 100 for white. According to the invention, an element is said to be "dark" if it has a lightness such that the L* value measured in reflection is less than 50. According to a particular embodiment applicable to all the configurations described in the present text, the absorbent layer is opaque, in the sense that its lightness is close to 0. In other words, it is not possible for a user to see through such an opaque layer.

[0063] Two embodiments of the projection screen 12 are presented below.

[0064] [Fig. 2] is a representation of a first embodiment of the projection screen 12.

[0065] In the following description, each surface mentioned is a surface parallel to the plane (O,X,Z).

[0066] The display 12 includes the lower substrate 121.

[0067] The lower substrate comprises the smooth lower surface 121_inf and the smooth upper surface 121_sup.

[0068] The lower substrate 121 is preferably made of glass (mineral) and is preferably transparent.

[0069] The projection screen 12 further comprises the lower layer 122, the central layer 123, the upper layer 124 and the absorbing layer 125 which extends partially along the smooth upper surface 121_sup of the lower substrate along the X axis, and which extends along the entire upper surface 121_sup along the Z axis.

[0070] Referring to [Fig. 2], lower layer 122 comprises a smooth lower surface 122_inf and a textured upper surface 122_sup.

[0071] With reference to [Fig.2], the upper layer 124 comprises a smooth upper surface 124_sup and a textured lower surface 124_inf.

[0072] The lower surface 122_inf of the lower layer 122, directed towards the outside of the screen 12, allows specular transmission of radiation to the upper surface 122_sup of the lower layer 122, i.e. the entry of radiation into the lower layer 122 or the exit of radiation from the lower layer 121.

[0073] The upper surface 124_sup of the upper layer 124, directed towards the outside of the screen 12, allows specular transmission of radiation to the lower surface 124_inf of the upper layer 124, i.e. the entry of radiation into the upper layer 124 or the exit of radiation from the upper layer 124.

[0074] The textures of the surfaces 124_inf and 122_sup are complementary to each other. As clearly visible in [Fig. 2], the textured surfaces 124_inf and 122_sup are positioned opposite each other, in a configuration where their textures are strictly parallel to each other.

[0075] According to one embodiment, the upper layer 124 of the screen 12 is a textured glass. Examples of textured glasses that can be used as an upper layer are glass substrates marketed by the company Saint-Gobain Glass in the SATINOVO® range, which have on one of their surfaces a texture obtained by sandblasting or acid etching, the glass substrates marketed by the company Saint-Gobain Glass in the ALBARINO® S, P range or G in the MASTERGLASS® range, which has a texture obtained by lamination on one of their main surfaces.

[0076] According to the embodiment in which the upper layer 124 of the screen 12 is a textured glass, the lower layer 122 of the screen 12 is preferably made of PVB (acronym for the expression “polyvinyl butyral”).

[0077] According to one embodiment, the central layer 123 of the projection screen 12 comprises at least one thin layer made of a dielectric material with a high refractive index, different from the refractive index of the material(s) forming the lower layer 121, such as SisN4, SnO2, ZnO, AIN, NbO, NbN, TiO2, or made of a dielectric material with a low refractive index, different from the refractive index of the outer layers, such as SiO2, AI2O3, MgF2, AIF3. The central layer 123 of the projection screen may also comprise at least one thin metallic layer, in particular a thin layer of silver, gold, titanium, niobium, silicon, aluminum, nickel-chromium alloy (NiCr), stainless steel, or their alloys.

[0078] For the purposes of the invention, a thin layer is a layer with a thickness of less than 1 micrometer.

[0079] The dimension of the absorbent layer 125 along the X axis is strictly less than the dimension of the lower substrate 121 along the Y axis and is substantially identical to the dimension of the lower substrate 121, and the dimension of the absorbent layer 125.

[0080] Referring to [Fig. 2], the absorbent layer 125 partially covers the upper surface 121_sup of the lower substrate 121 along the X axis and covers the entire upper surface 121_sup along the Z axis.

[0081] According to one embodiment, not shown, the absorbent layer 125 covers more than half of the upper surface 121_sup along the X axis and less than the entire upper surface 121_sup along the X axis and covers the entire upper surface 121_sup along the Z axis.

[0082] According to one embodiment, the absorbent layer 125 covers less than half of the upper surface 121_sup along the X axis and covers the entire upper surface 121_sup along the Z axis.

[0083] According to a variant of the embodiment of [Fig. 1] shown in [Fig. 3], the absorbent layer 123 is located on the lower surface 121_inf of the lower substrate 121 and partially covers said lower surface 121_inf.

[0084] Referring to [Fig. 3], the absorbent layer 125 partially covers the lower surface 121_inf of the lower substrate 121 along the X axis and covers the entire lower surface 121_inf along the Z axis.

[0085] According to one embodiment, not shown, the absorbent layer 125 covers more than half of the lower surface 121_inf along the X axis and less than the entire lower surface 121_inf along the X axis and covers the entire upper surface 121_sup along the Z axis.

[0086] According to one embodiment, the absorbent layer 125 covers less than half of the lower surface 121_inf along the X axis and covers the entire lower surface 121_inf along the Z axis.

[0087] The transparent portion 12a of the projection screen 12 is the portion of the projection screen 12 for which each plane perpendicular to the projection screen 12, i.e. each plane perpendicular to the plane (O, Y, Z), and passing through the projection screen 12 does not pass through the absorbent layer 125.

[0088] The dark part 12b of the projection screen 12 is the part of the projection screen 12 for which each plane perpendicular to the projection screen 12, that is to say each plane perpendicular to the plane (O, Y, Z), and passing through the projection screen 12 necessarily passes through the absorbent layer 125.

[0089] [Fig. 4] is a schematic representation of the projection screen 12 on which the transparent part 12a of the projection screen 12 and the dark part 12b of the projection screen can be observed.

[0090] Thus, the transparent portion 12a of the projection screen does not include the absorbent layer 125, and includes a first portion of each layer among the lower substrate 121, the lower layer 122, the central layer 123 and the upper layer 124.

[0091] Thus, the dark portion 12b of the projection screen does not include the absorbing layer 125, and includes the second portion of each layer among the lower substrate 121, the lower layer 122, the central layer 123 and the upper layer 124 and includes the entire absorbing layer 125.

[0092] The projection screen 12 comprises a first outer surface and a second outer surface. According to the embodiment of [Fig. 2], the first outer surface of the projection screen 12 is the upper surface 124_sup of the upper layer 124 and the second outer surface of the projection screen 12 is the lower surface 121_inf of the lower substrate 121.

[0093] Advantageously, the upper layer 124 may comprise on its upper surface 124_sup (which represents the first external surface of the projection screen 12 according to the embodiment of [Fig. 2]) an anti-reflective coating, not shown at the interface between the air and the material constituting the upper layer 127 forming this external main surface. Thanks to the presence of this anti-reflective coating, radiation incident on the projection screen 12 on the side of this upper surface 124_sup is reflected in a preferred manner at each textured contact surface rather than on the smooth upper surface 124_sup of the projection screen 12, which corresponds to a diffuse reflection mode rather than a specular reflection mode. A diffuse reflection of the radiation by the projection screen 12 is thus favored compared to a specular reflection.

[0094] [Fig. 5] is a representation of a second embodiment of the projection screen 12.

[0095] Referring to [Fig. 5], the projection screen 12 comprises, from bottom to top, the lower substrate 121, the intermediate layer 126 extending along the lower substrate, the lower layer 122, the central layer 123, the upper layer 124 and the upper substrate 127.

[0096] The upper substrate 127 comprises a smooth upper surface 127_sup and a smooth lower surface 127_inf.

[0097] The upper layer 124 is in contact with the upper substrate 127_sup according to a smooth interface.

[0098] Referring to [Fig. 5], the lower layer 122 comprises the smooth lower surface 122_inf and a textured upper surface 122_sup'.

[0099] The intermediate layer 126 is interposed between the lower layer 122 and the lower substrate 121.

[0100] The upper substrate 127 is transparent and may be formed of a transparent polymer, transparent glass, or transparent ceramic. When the transparent substrate 127 is formed of a polymer, the polymer may be rigid or flexible.

[0101] Preferably, the upper substrate 127 is the glass substrate marketed by the company Saint-Gobain Glass in the SGG PLANICLEAR range.

[0102] Referring to [Fig. 5], the upper layer 124 is preferably formed from OCA (Optical Clear Adhesive). The transparent adhesive material "OCA" refers to a set of polymeric materials which, in the case of the present invention, are used as transparent adhesives. Examples of polymeric materials suitable for the dielectric layer of the inner layer include, but are not limited to, polyurethane, polyepoxide, polysiloxane, polyacrylate, polyester, etc.

[0103] Advantageously, an upper layer 124 formed of OCA makes it possible to reduce or even eliminate a potential “waviness” effect across the assembly {layered element + central substrate} when the main exterior surface of the outer substrate is observed. Indeed, a waviness effect tends to give a visual impression of undulation of the layers placed between the outer substrate and the central substrate.

[0104] For example, according to the previous embodiment, the lower layer 127 has a thickness of between 200 μm and 250 μm. Such thickness values ​​are however not limiting of the invention.

[0105] The top layer 124 may be formed from the transparent adhesive material OCA, or from PVB ("Polyvinyl Butyral") which is a synthetic thermoplastic polymer, or from EVA ("Ethylene Vinyl Acetate") of PU (polyurethane).

[0106] The intermediate layer 126 is preferably made of PMMA and may have, for example, a thickness of between 50 μm and 250 μm. However, nothing precludes considering other materials for producing said intermediate layer, such as, for example, polycarbonate. Still other examples of suitable materials for said intermediate layer include, in particular, polyesters such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), polyacrylates such as polymethacrylate methyl (PMMA), polycarbonate, polyurethane, polyamides, polyimides, cellulose triacetate (CTAC), etc.

[0107] Advantageously, an upper layer 124 formed of PU is more chemically compatible with an intermediate layer 126 formed of PMMA.

[0108] Advantageously, the upper substrate 127 may comprise on its upper surface 127_sup (which represents the first external surface of the projection screen 12 according to the embodiment of [Fig. 5]) an anti-reflective coating, not shown, at the interface between the air and the material constituting the external layer forming this external main surface. Thanks to the presence of this anti-reflective coating, radiation incident on the projection screen 12 on the side of this upper surface 127_sup is reflected in a preferred manner at each textured contact surface rather than on the smooth upper surface 127_sup of the projection screen, which corresponds to a diffuse reflection mode rather than a specular reflection mode. A diffuse reflection of the radiation by the projection screen 12 is thus favored compared to a specular reflection.

[0109] With reference to [Fig. 5], the central layer 123 of the projection screen 12 comprises at least one thin layer made of a dielectric material with a high refractive index, different from the refractive index of the material(s) forming the lower layer 121, such as SisN4, SnO2, ZnO, AIN, NbO, NbN, TiC, or made of a dielectric material with a low refractive index, different from the refractive index of the outer layers, such as SiC>2, AI2O3, MgF2, AIF3. The central layer 123 of the projection screen may also comprise at least one thin metallic layer, in particular a thin layer of silver, gold, titanium, niobium, silicon, aluminum, nickel-chromium alloy (NiCr), stainless steel, or their alloys.

[0110] With reference to [Fig. 5] The dimension of the absorbent layer 125 along the X axis is strictly less than the dimension of the lower substrate 121 along the Y axis and is substantially identical to the dimension of the lower substrate 121, and the dimension of the absorbent layer 125.

[0111] Referring to [Fig. 5], the absorbent layer 125 partially covers the upper surface 121_sup of the lower substrate 121 along the X axis and covers the entire upper surface 121_sup along the Z axis.

[0112] According to one embodiment, not shown, the absorbent layer 125 covers more than half of the upper surface 121_sup along the X axis and less than the entire upper surface 121_sup along the X axis and covers the entire upper surface 121_sup along the Z axis.

[0113] According to one embodiment, the absorbent layer 125 covers less than half of the upper surface 121_sup along the X axis and covers the entire upper surface 121_sup along the Z axis.

[0114] According to a variant of the embodiment of [Fig. 5] shown in [Fig. 6], the absorbent layer 125 is located on the lower surface 121_inf of the lower substrate 121 and partially covers said lower surface 121_inf.

[0115] According to the embodiment of [Fig. 5], the first outer surface of the projection screen 12 is the upper surface 127_sup of the upper substrate 127 and the second outer surface of the projection screen 12 is the lower surface 121_inf of the lower substrate 121.

[0116] The transparent portion 12a of the projection screen 12 is the portion of the projection screen 12 for which each plane perpendicular to the projection screen 12, i.e. each plane perpendicular to the plane (O, Y, Z), and passing through the projection screen 12 does not pass through the absorbent layer 125.

[0117] The dark part 12b of the projection screen 12 is the part of the projection screen 12 for which each plane perpendicular to the projection screen 12, that is to say each plane perpendicular to the plane (O, Y, Z), and passing through the projection screen 12 necessarily passes through the absorbent layer 125.

[0118] [Fig. 7] is a schematic representation of the projection screen 12 on which the transparent part 12a of the projection screen 12 and the dark part 12b of the projection screen can be observed when the projection screen 12 is produced according to the embodiment of [Fig. 5],

[0119] Thus, the transparent portion 12a of the projection screen does not include the absorbent layer 125, and includes a first portion of each layer among the lower substrate 121, the lower layer 122, the central layer 123 and the upper layer 124.

[0120] Thus, the dark portion 12b of the projection screen does not include the absorbent layer 125, and includes the second portion of each layer among the lower substrate 121, lower layer 122, middle layer 123 and upper layer 124 and includes the entire absorbent layer 125.

[0121] Another aspect of the invention relates to a projection method whose block diagram is shown in [Fig. 8]. The projection method 100 is implemented by the projection system 1 according to the invention, said method comprising a first step 101 consisting of positioning the projector 11 opposite the screen 12 and a step 102 of projecting a light beam 111 covering both the transparent part 12a and the dark part 12b of the projection screen 12.

[0122] Another aspect of the invention relates to a method of manufacturing the screen 12 according to the first embodiment shown in [Fig. 2], of the projection system 1 according to the invention. The block diagram of the method of manufacturing the screen 12 according to the embodiment of [Fig. 2] is shown in [Fig. 9],

[0123] The manufacturing method 200 comprises a first step 201 of obtaining a first glass substrate comprising a first smooth main surface and a second opposite smooth main surface, said substrate forming the lower substrate 121, the first smooth main surface being the lower surface 121_inf of the lower substrate 121 and the second main surface being the upper surface 121_sup of the lower substrate 121.

[0124] The method 200 comprises a step 202 of screen-printing the absorbent layer 125 onto the lower substrate 121, the absorbent layer 125 extending along a portion of the lower substrate 121, the portion of the lower substrate 121 not being able to be the entirety of the lower substrate 121.

[0125] According to a first embodiment, the absorbent layer 125 is deposited on an upper surface portion 121_sup of the lower substrate 121.

[0126] According to a first embodiment, the absorbent layer 125 is deposited on a lower surface portion 121_inf of the lower substrate 121.

[0127] The manufacturing method 200 comprises a step 203 of obtaining a second glass substrate comprising a smooth main surface and a textured main surface, said second glass substrate forming the upper layer 124, said smooth main surface being the upper surface 124_sup of the upper layer 124 and said textured surface being the lower surface 124_inf of the upper layer 124.

[0128] The manufacturing method 200 comprises a step 204 of magnetron deposition of a conformal layer on the upper layer 124 and in particular on the textured lower surface 124_inf of the upper layer 124, said conformal layer forming the central layer 123.

[0129] The manufacturing method further comprises a step 205 of assembling by lamination the assembly formed by the upper layer 124 and the central layer 123 with the lower substrate 121, the assembly being carried out via an intermediate layer made of polymer adapted to deform thanks to a lamination step in order to match the textured surface of the central layer, the intermediate layer forming the lower layer 122.

[0130] Another aspect of the invention relates to a method of manufacturing the projection screen 12 according to the embodiment shown in [Fig. 5], of the projection system 1 according to the invention. Said method of manufacturing the projection screen 12 according to the embodiment of [Fig. 5] is shown in [Fig. 10],

[0131] The manufacturing method 300 comprises a first step 301 of obtaining a first glass substrate comprising a first smooth main surface and a second opposite smooth main surface, said first substrate forming the lower substrate 121, the first smooth main surface being the lower surface 121_inf of the lower substrate 121 and the second main surface being the upper surface 121_sup of the lower substrate 121.

[0132] The method 300 comprises a step 302 of screen-printing the absorbent layer 125 onto the lower substrate 121, the absorbent layer 125 extending along a portion of the lower substrate 121, the portion of the lower substrate 121 not being able to be the entirety of the lower substrate 121.

[0133] According to a first embodiment, the absorbent layer 125 is deposited on an upper surface portion 121_sup of the lower substrate 121.

[0134] According to a first embodiment, the absorbent layer 125 is deposited on a lower surface portion 121_inf of the lower substrate 121.

[0135] The manufacturing method 300 comprises a step 303 of obtaining a second glass substrate comprising a first smooth main surface and a second smooth main surface, said second glass substrate forming the upper substrate 127, said first smooth main surface being the upper surface 127_sup of the upper substrate 127, and said second smooth main surface being the lower surface 127_inf of the upper substrate 127.

[0136] The manufacturing method 300 comprises a step 304 of obtaining a third substrate 122 in the form of a plastic film, comprising a smooth main surface and a textured main surface, said smooth main surface being the lower surface 122_inf of the lower layer 122 and said textured surface being the upper surface 122_sup of the lower layer 122.

[0137] The manufacturing method 300 comprises a step 305 of magnetron deposition of a conformal layer on the lower layer 122 and in particular on the textured upper surface 122_sup of the lower layer 122, said conformal layer forming the central layer 123.

[0138] The manufacturing method further comprises a step 306 of assembly by lamination of the lower substrate 121 with the assembly formed by the lower layer 122 and the central layer 123, the assembly being carried out via the intermediate layer 126.

[0139] The manufacturing method further comprises a step 307 of assembling by lamination the upper substrate 127 with the assembly formed by the lower layer 122, the central layer 123, the intermediate layer 126 and the lower substrate 121, the assembly being carried out via the upper layer 124 which is adapted to deform in order to match a textured surface of the central layer 123.

Claims

CLAIMS

1. Projection system (1) comprising: - a projector (11); - a diffusely reflective projection screen (12) comprising a dark part (12b) and a transparent part (12a); said projector (11) being positioned opposite the projection screen (12) so that a light beam (111) emitted by the projector (11) covers both the dark part (12b) and the transparent part (12a) of the projection screen (12).

2. Projection system (1) according to the preceding claim, characterized in that the intensity of the light beam received by the dark part (12b) of the projection screen is different from the intensity of the light beam received by the transparent part (12a) of the projection screen. [Claim s] Projection system (1) according to any one of the preceding claims characterized in that the dark part (12b) has an area substantially equal to or different from an area of ​​the transparent part (12a).

4. Projection system (1) according to any one of the preceding claims, characterized in that the projection screen (12) is a layered element comprising: - a lower substrate (121) comprising a smooth upper surface (121_sup) and a smooth lower surface (121_inf); - an absorbent layer (125) extending along a portion of the lower substrate (121); - a lower layer (122) made of dielectric materials, said lower layer (122) being arranged above the lower substrate (121); - an upper layer (124) made of dielectric materials, the lower layer (122) and the upper layer (124) having substantially identical refractive indices; - a central layer (123) interposed between the lower layer (122) and the upper layer (124), this central layer (123) being formed either by a single layer which is a dielectric layer of refractive index different from that of the external layers or a metallic layer, or by a stack of layers which comprises at least one dielectric layer of refractive index different from that of the external layers or a metallic layer; where each contact surface between two adjacent layers of the projection screen (12) which are one dielectric and the other metallic, or which are two dielectric layers of different refractive indices, is textured and parallel to the other textured contact surfaces between two adjacent layers which are one dielectric and the other metallic or which are two dielectric layers of different refractive indices. [Claim s] Projection system (1) according to the preceding claim, characterized in that the projection screen (12) comprises a first outer surface and a second outer surface, and in that the projector (11) is opposite the outer surface of the projection screen (12) furthest from the absorbent layer (125) among the first outer surface and the second outer surface. [Claim s] Projection system (1) according to any one of claims 4 to 5 characterized in that the upper layer (124) is a glass substrate comprising a smooth upper surface (124_sup) and a textured lower surface (124_inf), the textured lower surface (124_inf) being in contact with the central layer (123).

7. Projection system (1) according to the preceding claim, characterized in that: - the first outer surface of the projection screen (12) is the upper surface (124_sup) of the upper layer (124); - the second outer surface of the projection screen (12) is the lower surface (121_inf) of the lower substrate (121); and in that the outer surface furthest from the absorbent layer (125) is the first outer surface.

8. Projection system (1) according to one of claims 4 to 5 characterized in that the projection screen (12) comprises an outer substrate (127) in contact with the outer layer (124) and comprises an intermediate layer (126), preferably made of a material polymer, in contact along a smooth interface with the lower layer (122) and in contact along a smooth interface with the lower substrate (121), the assembly formed by the upper layer (124), the central layer (123), the lower layer (122) and the intermediate layer (126) being comprised between the lower substrate (121) and the upper substrate (127).

9. Projection system (1) according to the preceding claim, characterized in that: - the first outer surface of the projection screen (12) is the upper surface (127_sup) of the upper substrate (127); - the second outer surface of the projection screen (12) is the lower surface (121_inf) of the lower substrate (121); and in that the outer surface furthest from the absorbent layer (125) is the first outer surface.

10. Projection system (1) according to any one of claims 4 to 9 characterized in that the lower substrate (121) is made of glass.

11. Projection system (1) according to any one of claims 4 to 9 characterized in that the lower substrate (121) is transparent.

12. Projection system (1) according to the preceding claim characterized in that the lower substrate (121) is absorbent.

13. Projection method (100) implemented by the projection system (1) according to any one of claims 1 to 12 and comprising a step (101) of positioning the projector (11) opposite the screen (12) and a step (102) of projecting a light beam (111) covering both the transparent part (12a) and the dark part (12b) of the projection screen (12).

14. Method (200) of manufacturing a projection system (1) according to any one of claims 1 to 7 and claims 10 to 12, characterized in that it comprises the following steps: - obtaining (201) a first substrate, preferably made of glass, comprising a first smooth main surface and a second opposite smooth main surface, said substrate forming the lower substrate (121), the first smooth main surface being the surface lower (121_inf) of the lower substrate (121) and the second main surface being the upper surface (121_sup) of the lower substrate (121); - deposition (202), preferably by screen printing, of the absorbent layer (125) on the lower substrate (121), the absorbent layer (125) extending along a portion of the lower substrate (121); - obtaining (203) a second substrate, preferably made of glass, comprising a smooth main surface and a textured main surface, said second substrate forming the upper layer (124), said smooth main surface being the upper surface (124_sup) of the upper layer (124) and said textured surface being the lower surface (124_inf) of the upper layer (124); - deposition (204), preferably by magnetron and / or screen printing, of a conformal layer on the upper layer (124) and in particular on the lower surface (124_inf), textured, of the upper layer (124), said conformal layer forming the central layer (123); - assembly (205) by lamination of the assembly formed by the upper layer (124) and the central layer (123) with the lower substrate (121), the assembly being carried out via an intermediate layer, preferably made of polymer, adapted to deform in order to match a textured surface of the central layer (123), the intermediate layer forming the lower layer (122).

15. Method (300) of manufacturing a projection system (1) according to any one of claims 1 to 5 and 8 to 12, characterized in that it comprises the following steps: - obtaining (301) a first substrate, preferably made of glass, comprising a first smooth main surface and a second opposite smooth main surface, said first substrate forming the lower substrate (121), the first smooth main surface being the lower surface (121_inf) of the lower substrate (121) and the second main surface being the upper surface (121_sup) of the lower substrate (121); Tl - deposition (302), preferably by screen printing, of the absorbent layer (125) on the lower substrate (121), the absorbent layer (125) extending along a portion of the lower substrate (121); - obtaining (303) a second substrate, preferably made of glass, comprising a first smooth main surface and a second smooth main surface, said second substrate forming the upper substrate (127), said first smooth main surface being the upper surface (127_sup) of the upper substrate (127), and said second smooth main surface being the lower surface (127_inf) of the upper substrate (127); - obtaining (304) a third substrate (122), preferably in the form of a plastic film, comprising a smooth main surface and a textured main surface, said smooth main surface being the lower surface (122_inf) of the lower layer (122) and said textured surface being the upper surface (122_sup) of the lower layer (122); - deposition (305), preferably by magnetron and / or screen printing, of a conformal layer on the lower layer (122) and in particular on the textured upper surface (122_sup) of the lower layer (122), said conformal layer forming the central layer (123); - assembly (306) by lamination of the lower substrate (121) with the assembly formed by the lower layer (122) and the central layer (123), the assembly being carried out via the intermediate layer (126); - assembly (307) by lamination of the upper substrate (127) with the assembly formed by the lower layer (122), the central layer (123), the intermediate layer (126) and the lower substrate (121), the assembly being carried out via the upper layer (124) which is adapted to deform in order to match a textured surface of the central layer (123).

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