Display device with cover lens, and manufacturing method thereof

Abstract

Display device with cover lens, and associated manufacturing method The present invention relates to a display device (10) comprising a display assembly (12), and a cover lens (14), the display assembly (12) being adapted to display an image on a display face (18) of the display assembly (12), the cover lens (14) comprising a rear face (20) extending opposite the display face (18), the display face (18) and the rear face (20) of the cover lens (14) being spaced apart from each other, the display device (10) comprising a lens anti-reflection layer (36) and a polarizing layer (38), the polarizing layer (38) being arranged against the rear face (20) of the cover lens (14), the lens anti-reflection layer (36) being arranged against the polarizing layer (38), preferably by lamination or varnishing.The invention further relates to an associated manufacturing method. Figure for abstract: Fig 1.

Description

Title of the invention: Display device with cover lens, and associated manufacturing method

[0001] The present invention relates to a display device comprising a display assembly, and a cover lens, the display assembly and the cover lens being spaced apart from each other.

[0002] The present invention further relates to an associated manufacturing method.

[0003] Such display devices are known.

[0004] However, the space between the display assembly and the cover lens results in a so-called "airgap" effect, in which the contrast of the image visible to a user of the display device is reduced, reflections are likely to impede viewing of the image displayed by the display assembly, and the quality of the comfort display is reduced.

[0005] One solution is to inject an optically clear liquid adhesive between the display assembly and the cover lens or to place an optically clear adhesive in a form other than liquid between the display assembly and the cover lens, to fill the air gap.

[0006] However, this is very expensive. In particular, for injecting a silicone-based liquid adhesive, the material is likely to cost between 10 and 20% of the cost to manufacture the device as a whole.

[0007] Furthermore, the addition of a layer of optically transparent adhesive that fills the entire gap between the display assembly and the cover lens makes the device significantly heavier.

[0008] Finally, such a device is not repairable or recyclable due to the optical silicone bonding.

[0009] The aim of the invention is therefore to propose a display device which does not have a so-called "airgap" effect, is economical, has no excess mass, and is more easily repairable and / or recyclable.

[0010] For this purpose, the subject of the invention is a display device comprising a display assembly, and a cover lens, the display assembly being adapted to display an image on a display face of the display assembly, the cover lens comprising a rear face extending opposite the display face, the display face and the rear face of the cover lens being spaced apart from each other, the display device comprising a lens anti-reflection layer and a polarizing layer, the polarizing layer being arranged against the rear face of the cover lens, the lens anti-reflection layer being arranged against the polarizing layer, preferably by lamination or varnishing.

[0011] The anti-reflection layer limits reflection at the back of the lens, which accumulates in light from the display assembly. In addition, the polarizing layer selects light from the display assembly.

[0012] According to other advantageous aspects of the invention, the display device comprises one or more of the following characteristics, taken individually or in all technically possible combinations:

[0013] - the display device comprises an anti-reflection display layer on the face display;

[0014] - the anti-reflection display layer has nanostructures having a length between 220 nm and 250 nm, or the display anti-reflection layer has a first reflective surface, a second reflective surface and a quarter-wave plate, the first reflective surface and the second reflective surface being separated from the quarter-wave plate;

[0015] - the anti-reflection lens layer has nanostructures having a length between 220 nm and 250 nm, or the lens anti-reflection layer has a first reflective surface, a second reflective surface and a quarter-wave plate, the first reflective surface and the second reflective surface being separated from the quarter-wave plate;

[0016] - the space between the display face and the back face of the cover lens is consisting of air except for the lens anti-reflection layer and the polarizing layer, and where applicable the display anti-reflection layer;

[0017] - the polarizing layer comprises a rectilinear polarizer adapted to select in any incident light wave a preferential direction of polarization, more particularly adapted to absorb between 40% and 80%, preferentially between 40% and 60% of the unpolarized light or having a polarization different from the preferential direction of polarization and lets pass all of the polarized light according to the preferential direction of polarization;

[0018] - the display assembly emits polarized light according to the polarization direction preferential;

[0019] - the cover lens is smoked; and / or

[0020] - the rear face of the cover lens is curved.

[0021] The invention also relates to a method of manufacturing the display device as described above, comprising the following steps:

[0022] - provision of a display assembly adapted to display an image on one face display of the display assembly,

[0023] - providing a cover lens comprising a rear face, a po layer being arranged against the rear face of the cover lens, a layer anti-reflection lens being arranged against the polarizing layer, preferably by lamination or by varnishing, and

[0024] - arrangement of the cover lens opposite the display assembly, so that the back face of the cover lens extends opposite the display face.

[0025] The invention will appear more clearly on reading the description which follows, given solely by way of non-limiting example, and made with reference to the drawings in which:

[0026] [Fig-1] [Fig.l] is a schematic sectional view of an example of a device display according to one embodiment of the invention.

[0027] An example of a display device according to an embodiment of the invention is shown in [Fig.l].

[0028] The display device 10 comprises a display assembly 12 and a cover lens 14.

[0029] The display device 10 further comprises here a support assembly 16.

[0030] The display assembly 12 has a display face 18.

[0031] A longitudinal direction X is defined corresponding to the direction perpendicular to the display face 18.

[0032] The display assembly 12 is adapted to display an image on the display face 18.

[0033] The display assembly 12 is, for example, a liquid crystal display module.

[0034] The cover lens 14 has a rear face 20.

[0035] The rear face 20 extends opposite the display face 18.

[0036] The cover lens 14 further comprises a front face 22 opposite the rear face 20, more particularly opposite in the longitudinal direction X.

[0037] The cover lens 14 has an optical axis parallel to the longitudinal direction X.

[0038] The display face 18 and the rear face 20 are spaced from each other in the longitudinal direction X.

[0039] More particularly, the distance between the display face 18 and the rear face 20 is between 0.2 mm and 10 mm.

[0040] The maximum distance measured in the longitudinal direction X between the display face 18 and the rear face 20 is between 0.2 mm and 10 mm.

[0041] The projection of the display face 18 onto the rear face 20 in the longitudinal direction X is included in the rear face 20.

[0042] In other words, the lens extends at least opposite the entire display face.

[0043] The rear face 20 of the cover lens 14 is, for example, curved here.

[0044] More particularly, the cover lens 14 is here convex at the level of the rear face 20.

[0045] The cover lens 14 is, for example, a concave-convex lens.

[0046] The distance between the rear face 20 and the front face 22 is, for example, constant over the entire extent of the rear face 20 and the front face 22.

[0047] The cover lens 14 is, for example, made of polycarbonate.

[0048] The cover lens 14 here has a so-called neutral tint, that is to say that it does not does not modify the colorimetry of the transmitted light, in particular the a and b values ​​of the light in the L*a*b* CIE 1976 or CIELab color space.

[0049] In a particular embodiment, the cover lens 14 is smoked, for example during its manufacture.

[0050] More particularly, the lens has a light transmission rate of between 70% and 90%.

[0051] Smoking improves the continuity of appearance between the display area of ​​the screen and the decorative outline, generally black, when the screen is off.

[0052] Alternatively, the cover lens 14 is optically transparent.

[0053] The cover lens 14 is fixed relative to the display assembly 12.

[0054] The support assembly 16 is adapted to hold the cover lens 14 and the display assembly 12 together.

[0055] The support assembly 16 comprises, for example, a housing 24 and a holding structure 26 of the display assembly 12.

[0056] The housing 24 has, for example, a bottom wall 28 and side walls 30, together defining a receiving volume 32 for the display assembly 12.

[0057] The housing 24 is, for example, opaque here.

[0058] The end of the side walls opposite the bottom wall 28 is, for example, here provided with a rim 34.

[0059] The rim 34 here extends over the entire contour formed by the end.

[0060] The rim 34 here extends perpendicular to the longitudinal direction X.

[0061] The rim 34 extends here from the end towards the receiving volume 32.

[0062] The rim 34 is opaque here.

[0063] The cover lens 14 is here secured to the side walls 30, opposite the bottom wall 28.

[0064] The cover lens 14 closes the receiving volume 32.

[0065] The rim 34 extends, for example, between the cover lens 14 and the side walls 30.

[0066] The rim 34 is, for example, dimensioned perpendicular to the longitudinal direction, more particularly in a direction tangent to the side wall 30 cor corresponding, so that the contour of the display assembly 12 extends opposite the rim 34 in the longitudinal direction X, more particularly extends opposite a distal end of the rim 34 in the longitudinal direction X.

[0067] The rim 34 makes it possible in particular to hide what is arranged next to the display assembly 12 in the receiving volume 32.

[0068] The holding structure 26 of the display assembly 12 holds the display assembly and is fixed relative to the housing 24.

[0069] More particularly, the holding structure 26 is fixed to the bottom wall.

[0070] Thus, the support assembly holds the cover lens and the display assembly relative to each other.

[0071] Further, only the cover lens and the housing form the exterior of the display device 10.

[0072] According to the invention, the display device 10 comprises a lens anti-reflection layer 36 and a polarizing layer 38, the lens anti-reflection layer 36 and the polarizing layer 38 being arranged on the rear face 20 of the cover lens 14.

[0073] More particularly, the polarizing layer 38 being arranged against the rear face 20 of the cover lens 14, the lens anti-reflection layer 36 being arranged against the polarizing layer 38, preferably by lamination or by varnishing.

[0074] In a particular embodiment of the invention, the display device 10 further comprises an anti-reflection display layer 40 on the display face 18.

[0075] The space between the display face 18 and the rear face 20 of the cover lens 14 is made of air with the exception of the lens anti-reflection layer 36 and the polarizing layer 38, and where applicable the display anti-reflection layer 40.

[0076] The polarizing layer 38 extends at least over the entire portion of the rear face 20 of the cover lens 14 extending opposite the display face 18.

[0077] More particularly, here, the polarizing layer 38 extends against the entire rear face 20 arranged inside relative to the rim 34.

[0078] The polarizing layer 38 comprises, for example, a rectilinear polarizer selecting a preferential polarization direction in any incident light wave.

[0079] The polarization direction here corresponds to a polarization direction of the light emitted by the display assembly 12.

[0080] More particularly here, the polarizing layer absorbs between 40% and 80%, preferably between 40% and 60% of the unpolarized light or light having a polarization different from the preferred polarization direction and lets all of the polarized light pass according to the preferred polarization direction.

[0081] This makes it possible in particular to filter a part of the light wave which does not correspond not to the light emitted by the display assembly 12, since it does not correspond to the polarization direction of the light emitted by the display assembly 12.

[0082] The lens anti-reflection layer 36 extends at least opposite the entire portion of the rear face 20 of the cover lens 14 extending opposite the display face 18.

[0083] More particularly, here, the lens anti-reflection layer 36 extends over the entire polarizing layer 38.

[0084] The lens anti-reflection layer 36 has, for example, nanostructures having a length between 220 nm and 250 nm.

[0085] The anti-reflection lens layer 36 here has the nanostructures over an entire surface 42, more particularly over an entire surface 42 extending opposite the polarizing layer 38.

[0086] The surface 42 extends at least opposite the display face 18.

[0087] The lens anti-reflection layer 36 is, for example, a film having said nanostructures, for example a so-called “moth eye” film.

[0088] Alternatively, the nanostructures are overmolded on the rear face 20, for example in polyurethane, or alternatively molded in polycarbonate.

[0089] In an alternative embodiment, the lens anti-reflection layer 36 has a first reflective surface, a second reflective surface, and a quarter-wave plate, the first reflective surface and the second reflective surface being separated by the quarter-wave plate.

[0090] More particularly, each reflective surface is reflective for light incident on one side of the surface, here for light coming from the lens, and transmits light incident on the other side of the surface.

[0091] The first reflective surface has, for example, a first reflection coefficient RI for light incident from the lens 14 on the first reflective surface, and the second reflective surface has a second reflection coefficient R2 for light incident from the lens 14 on the second reflective surface.

[0092] The first reflection coefficient RI and the second reflection coefficient are, for example, such that R2 is equal to RI divided by (1-R1).

[0093] This allows in particular that the intensity of the light reflected by the second reflecting surface is equal to the intensity of the light reflected by the first reflecting surface.

[0094] The first reflective surface here corresponds to the entire surface extending opposite the polarizing layer 38.

[0095] The second reflective surface is opposite the first reflective surface.

[0096] The quarter-wave plate here has a thickness equal to a quarter of the wavelength of 550 nm.

[0097] Said wavelength is the wavelength most sensitive to the eye.

[0098] Alternatively, the lens anti-reflection layer 36 comprises a plurality of quarter-wave plates, each quarter-wave plate separating two reflective surfaces, as described above, for different wavelengths of the visible spectrum. The lens anti-reflection layer 36 comprises, for example, up to six quarter-wave plates.

[0099] The quarter-wave plate is, for example, produced by a coating or varnish, in particular produced by a sol-gel process.

[0100] The first reflecting surface reflects a first portion of the incident light from the cover lens 14, therefore from the polarizing layer 38, and transmits a second portion of the incident light towards the second reflecting surface.

[0101] The quarter-wave plate creates a phase shift of 90°, that is to say a delay of a quarter of a wavelength.

[0102] A third portion of the second portion of the incident light is then reflected by the second reflecting surface towards the first reflecting surface.

[0103] The quarter-wave plate then again creates a phase shift of 90°, that is to say a total delay of half a wavelength compared to the first portion of the light.

[0104] The reflection coefficients being chosen such that the intensity of the third portion is substantially equal to the intensity of the first portion, the third portion cancels the first portion of light thanks to the phase shift.

[0105] Alternatively, the lens anti-reflection layer 36 is made in any other way.

[0106] In the embodiment shown, the back face 20 of the cover lens 14, the polarizing layer 38, and the lens anti-reflection layer 36 are arranged in this order.

[0107] Alternatively, the back face 20 of the cover lens 14, the lens anti-reflection layer 36, and the polarizing layer 38 are arranged in this order.

[0108] In this alternative, the nano-structures of the lens anti-reflection layer 36 are, for example, molded directly with the lens in the lens material. The lens anti-reflection layer 36 is then included in the lens material.

[0109] The production of the polycarbonate nanostructures with a polycarbonate lens allows for better recyclability of the device, by separating the lens with the lens anti-reflection layer 36 from the rest of the device, which allows the lens to be recycled with the lens anti-reflection layer.

[0110] The display anti-reflection layer 40 extends over the entire display face 18.

[0111] The display anti-reflection layer 40 has, for example, nanostructures having a length between 220 nm and 250 nm.

[0112] The anti-reflection display layer 40 here has the nanostructures over an entire surface, more particularly over the entire surface 44 extending opposite the cover lens 14.

[0113] Here, the nanostructures extend over the entire surface extending opposite the display face 18.

[0114] The anti-reflection display layer 40 is, for example, a film having said nanostructures, for example a so-called “moth eye” film.

[0115] In an alternative embodiment, the display anti-reflective layer 40 has a first reflective surface, a second reflective surface, and a quarter-wave plate, the first reflective surface and the second reflective surface being separated by the quarter-wave plate.

[0116] More particularly, each reflective surface is reflective for light incident on one side of the surface, here for light coming from the lens, and transmits light incident on the other side of the surface.

[0117] The first reflective surface has, for example, a first reflection coefficient RI for light incident from the lens, and the second reflective surface has a second reflection coefficient R2 for light incident from the first reflective surface.

[0118] The first reflection coefficient RI and the second reflection coefficient are, for example, such that R2 is equal to RI divided by (1-R1).

[0119] This allows in particular that the intensity of the light reflected by the second reflecting surface is equal to the intensity of the light reflected by the first reflecting surface.

[0120] The first reflective surface here corresponds to the entire surface 44 extending opposite the cover lens 14.

[0121] The second reflective surface is opposite the first reflective surface.

[0122] The second reflective surface extends against the display face 18.

[0123] The quarter-wave plate here has a thickness equal to a quarter of the wavelength of 550 nm.

[0124] Said wavelength is the wavelength most sensitive to the eye.

[0125] Alternatively, the lens anti-reflection layer 36 comprises a plurality of quarter-wave plates, each quarter-wave plate separating two reflective surfaces, as previously described, for different wavelengths of the visible spectrum. The lens anti-reflection layer 36 comprises, for example, up to six quarter-wave plates.

[0126] The quarter-wave plate is, for example, produced by a coating or varnish, in particular produced by a sol-gel process.

[0127] The first reflective surface reflects a first portion of the incident light toward the display assembly and transmits a second portion of the incident light toward the second reflective surface.

[0128] The quarter-wave plate creates a phase shift of 90°, that is to say a delay of a quarter of a wavelength.

[0129] A third portion of the second portion of the incident light is then reflected by the second reflecting surface towards the first reflecting surface.

[0130] The quarter-wave plate then again creates a phase shift of 90°, that is to say a total delay of half a wavelength compared to the first portion of the light.

[0131] The reflection coefficients being chosen such that the intensity of the third portion is substantially equal to the intensity of the first portion, the third portion cancels the first portion of light thanks to the phase shift.

[0132] Alternatively, the display anti-reflection layer 40 is made in any other way.

[0133] The display anti-reflection layer limits the reflection of incident light at the display face, which is added to the light emitted by the display device.

[0134] A method of manufacturing a display device 10 as described previously will now be described.

[0135] The method comprises the following steps:

[0136] - providing a display assembly 12 as described previously, a layer display anti-reflection 40 being optionally arranged on the display face 18,

[0137] - providing a cover lens 14 as previously described, a lens anti-reflection layer 36 and a polarizing layer 38 being arranged on the back face 20 of the cover lens 14, and

[0138] - arrangement of the cover lens 14 opposite the display assembly 12, so that the rear face 20 of the cover lens 14 extends opposite the display face 18.

[0139] The polarizing layer 38 is, for example, previously arranged against the rear face 20 of the cover lens 14.

[0140] The lens anti-reflection layer 36 is then formed or arranged against the polarizing layer 38, preferably by lamination or by varnishing.

[0141] Where appropriate, the anti-reflection display layer 40 is previously formed or arranged against the display face 18, for example by applying a film, for example overmolding on the rear face 20, or by sol-gel process, as described previously.

[0142] Alternatively, the lens anti-reflection layer 36 is previously formed or arranged against the rear face 20 of the cover lens 14, for example by applying a film, by overmolding on the rear face 20, or by sol-gel process, as described previously.

[0143] The cover lens 14 and the display assembly 12 are secured to each other during arrangement, here by the support assembly 16.

[0144] Here, during the arrangement step, the display assembly 12 is placed so as to be held by the holding structure 26, the display face 18 being oriented opposite the opening of the receiving volume 32 delimited by the holding structure 26, for example by clipping in place, then the cover lens 14 is fixed on the ends of the side walls 30 opposite the bottom wall 28, for example by gluing, so that the rear face 20 extends opposite the display face 18.

[0145] A display device according to the invention makes it possible to limit the quantity of light which reaches the eyes of a user, other than the light emitted directly by the display device.

[0146] This allows in particular better contrasts, better display quality, fewer unwanted reflections and better repairability and recyclability in the absence of silicone optical bonding.

Claims

Claims

1. A display device (10) comprising a display assembly (12), and a cover lens (14), the display assembly (12) being adapted to display an image on a display face (18) of the display assembly (12), the cover lens (14) comprising a back face (20) extending opposite the display face (18), the display face (18) and the back face (20) of the cover lens (14) being spaced apart from each other, the display device (10) comprising a lens anti-reflection layer (36) and a polarizing layer (38), the polarizing layer (38) being arranged against the back face (20) of the cover lens (14), the lens anti-reflection layer (36) being arranged against the polarizing layer (38), preferably by lamination or varnishing.

2. A display device according to claim 1, comprising a display anti-reflection layer (40) on the display face (18).

3. The display device of claim 2, wherein the display anti-reflection layer (40) has nanostructures having a length of between 220 nm and 250 nm, or the display anti-reflection layer (40) has a first reflective surface, a second reflective surface and a quarter-wave plate, the first reflective surface and the second reflective surface being separated from the quarter-wave plate.

4. A display device according to any one of claims 1 to 3, wherein the lens anti-reflection layer (36) has nanostructures having a length of between 220 nm and 250 nm, or the lens anti-reflection layer (36) has a first reflective surface, a second reflective surface and a quarter-wave plate, the first reflective surface and the second reflective surface being separated from the quarter-wave plate.

5. A display device according to any one of claims 1 to 4, wherein the space between the display face (18) and the back face (20) of the cover lens (14) is air except for the lens anti-reflection layer (36) and the polarizing layer (38), and where applicable the display anti-reflection layer (40).

6. A display device according to any one of claims 1 to 5, wherein the polarizing layer (38) comprises a linear polarizer adapted to select from any incident light wave a preferential polarization direction, more particularly adapted to absorb between 40% and 80%, preferably between 40% and 60% of the unpolarized light or having a polarization different from the preferential polarization direction and allows all of the polarized light to pass according to the preferential polarization direction.

7. A display device according to claim 6, wherein the display assembly emits light polarized according to the preferred polarization direction.

8. A display device according to any one of claims 1 to 7, wherein the cover lens (14) is smoked.

9. A display device according to any one of claims 1 to 8, wherein the rear face (20) of the cover lens (14) is curved.

10. A method of manufacturing the display device (10) according to any one of claims 1 to 9, comprising the following steps: - providing a display assembly (12) adapted to display an image on a display face (18) of the display assembly (12), - providing a cover lens (14) comprising a rear face (20), a polarizing layer (38) being arranged against the rear face (20) of the cover lens (14), a lens anti-reflection layer (36) being arranged against the polarizing layer (38), preferably by lamination or by varnishing, and - arranging the cover lens (14) opposite the display assembly (12), such that the rear face (20) of the cover lens (14) extends opposite the display face (18).

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