FR3082626A1 - DISPLAY DEVICE AND MANUFACTURING METHOD THEREOF - Google Patents

Abstract

The invention relates to a display device (200) comprising: - an optical surface (10), - at least one external layer covering at least part of the optical surface (10), - at least one opaque zone (14) comprising an opaque element (16) disposed between the optical surface (10) and the external layer, and - at least one translucent display area (18) delimited by at least one edge (20) of the opaque element (16) . The display device (200) includes a translucent transition element (24) disposed on the optical surface (10), the transition element (24) extending to the display area (18) from an edge in contact with the opaque element (16).

Description

Display device and associated manufacturing method

The present invention relates to a display device comprising:

- an optical surface,

- at least one outer layer covering at least part of the optical surface,

at least one opaque zone comprising an opaque element disposed between the optical surface and the external layer, and

- at least one translucent display area delimited by at least one edge of the opaque element.

Such a display device is for example integrated in a trim element of a vehicle, such as a dashboard cover, a door panel or the like. The device is typically intended to display information useful to the driver and / or passengers such as GPS navigation information, pictograms, or the like.

The opaque element generally forms a mask extending over the optical surface and makes it possible to delimit one or more display zones with aesthetic and decorative outlines or delimiting the shape of a screen, a pictogram or the like.

The outer layer is for example a layer of translucent appearance deposited in the form of a film intended to fix a second optical surface on the first optical surface. Preferably, the outer layer is a layer of OCA film (Optically Clear Adhesive, in English, optically transparent adhesive, in French). The external layer in particular makes it possible to improve the optical performance of the display, for example by limiting reflections or by improving the display contrast. This is particularly advantageous inside the passenger compartment of a vehicle where the brightness varies greatly depending on the movement of the vehicle. Finally, the outer layer improves the strength and longevity of the display device. Indeed, thanks to the outer layer, the first optical surface is protected against shocks, scratches, and is less susceptible to significant temperature differentials, etc.

When the outer layer is applied to the optical surface and to the opaque appearance layer, and particularly when the appearance layer is thick, air bubbles can however be created at the interface between the outer layer, the surface optical layer and the opaque appearance layer, as shown in Figure 1, which degrades the quality of the image displayed by the display device.

In this context, an objective of the invention is to propose a display device which is simple and quick to manufacture and which makes it possible to avoid the creation of air bubbles at the interface between the optical surface, the opaque element. and the outer layer.

To this end, the invention relates to a display device of the aforementioned type in which said display device comprises a translucent transition element disposed on the optical surface, the transition element extending towards the display area at from an edge in contact with the opaque element.

Thus, the translucent transition element makes it possible to eliminate as much as possible the formation of air bubbles at the interface between the external layer, the opaque element and the optical surface, without degrading the optical quality perceived thanks to its translucent nature. . Indeed, the transition element extends where these air bubbles are likely to form and it forms with the outer layer a substantially uniform optical quality.

According to different embodiments, the display device has one or more of the characteristics below, considered individually or in all technically possible combinations:

- the transition element has a decreasing thickness from the edge in contact with the opaque element towards the display area;

the opaque element and the transition element respectively comprise at least one layer of opaque ink and at least one layer of translucent ink;

- The transition element comprises at least a first layer of translucent ink and a second layer of translucent ink, the second layer of translucent ink covering part of the first layer of translucent ink;

- In a local direction perpendicular to the opaque element, a dimension of the second layer of translucent ink is less than a dimension of the first layer of translucent ink;

the opaque element and the transition element comprise the same number of layers of opaque ink and of translucent ink respectively;

- the thickness of the translucent ink layer and the thickness of the opaque ink layer are identical;

- the thickness of the translucent ink layer and / or the thickness of the opaque ink layer is between 0.01 mm and 0.1 mm.

The invention also relates to a method of manufacturing a display device as described above, comprising:

- an optical surface;

- at least one outer layer covering at least part of the optical surface;

- at least one opaque zone comprising an opaque element disposed between the optical surface and the external layer;

- at least one translucent display area delimited by at least one edge of the opaque element;

characterized in that the method comprises a step of placing a translucent transition element disposed on the optical surface, the transition element extending towards the display area from an edge in contact with the opaque element.

According to different embodiments, the manufacturing process has one or more of the characteristics below, considered individually or according to all technically possible combinations:

the step of placing the transition element comprises depositing at least one layer of translucent ink, the method further comprising a step of depositing at least one layer of opaque ink in contact with the translucent ink layer, the opaque ink layer forming the opaque element;

- the translucent ink layer and / or the opaque ink layer are deposited by an additive manufacturing process.

Other characteristics and advantages of the invention will emerge from the detailed description which is given below, by way of indication and in no way limitative, with reference to the appended figures among which:

- Figure 1 is a schematic section of a part of a display device having the drawbacks mentioned in the introductory part of this application,

FIG. 2 is a schematic section of a part of a display device according to the invention, in a local direction perpendicular to the opaque element, and

- Figure 3 is a schematic section of a part of a display device of Figure 2 according to a particular embodiment.

In the following description, the term "translucent" is said to be a light transmitting body, that is to say having a light transmission rate of between 5% and 100%.

The term “transparent” means a body transmitting light by refraction and through which objects are clearly visible, that is to say a body having a light transmission rate greater than 95%, by example close to 100%.

The term "opaque" designates a body that lets little or no light pass, that is to say an object with a light transmission rate of less than 5%, or even close to 0%.

Light is considered in the visible range, that is to say composed of electromagnetic waves whose wavelength is generally between 380 nm and 780 nm.

The terms "outside" and "outside" qualify what is facing the outside of the display.

Figure 1 and Figure 2 respectively illustrate a display device 100 which have the drawbacks mentioned in the introduction to the present application and a display device 200 according to the invention which overcomes these drawbacks.

The display devices 100, 200 are for example navigation assistants intended to be fixed inside the passenger compartment of a vehicle, in particular in a trim panel of the vehicle.

Each display device 100, 200 comprises an optical surface 10.

For example, the optical surface 10 is a screen surface, a translucent protective element or a translucent tactile layer.

As shown in Figures 1 and 2, the optical surface 10 is substantially planar.

Alternatively, the optical surface 10 is curved.

The display devices 100, 200 also include at least one external layer 12 covering at least part of the optical surface 10. According to one embodiment, the external layer 12 covers the entire optical surface 10.

For example, the external layer 12 is a layer of translucent adhesive suitable for allowing the assembly by gluing of an external optical surface (not shown) on the optical surface 10.

The adhesive is for example a translucent liquid or a translucent gel.

Alternatively, the adhesive is transparent.

For example, the adhesive is a photopolymer suitable for polymerizing upon exposure to ultraviolet light.

As a variant, the external layer 12 is a layer of translucent or transparent appearance forming the external surface of the display device.

For example, the outer layer 12 is a skin of translucent or transparent appearance. The appearance skin is for example a translucent or transparent film.

The display devices 100, 200 comprise at least one opaque zone 14 comprising an opaque element 16 disposed between the optical surface 10 and the external layer 12. The opaque zone 14 therefore does not allow light to pass through coming from the optical surface 10 .

The opaque element 16 is preferably fixed to the optical surface 10.

The display devices 100, 200 comprise at least one translucent display area 18 delimited by at least one edge 20 of the opaque element 16. The shape of the display area is therefore defined by the shape of one or more several opaque elements 16 surrounding the display area. In the case of a screen, the display area 18 is for example of substantially rectangular shape. The display device could comprise several opaque elements 16 defining for example a backlit pattern on the external surface of the display device by delimiting several display areas of particular shapes.

As can be seen in FIG. 1, when the thickness of the opaque element is large, for example greater than or equal to 0.01 mm, air bubbles 22 may appear at the interface between the optical surface 10, the element opaque 16 and the outer layer 12 due to the difference in height between the outer surface of the opaque element 16 and the optical surface 10. In this case, the outer layer 12 may not fill the corner formed between the opaque element 16 and the optical surface 10.

To overcome this problem, the device 200 according to the invention (FIG. 2) comprises a translucent transition element 24 placed on the optical surface 10 against the opaque area 14 and extending towards the display area 18.

The transition element 24 includes an edge 26 in contact with the opaque element 16.

The transition element 24 extends to the display area 18 from the edge 26. The transition element 24 thus partially covers the display area 18.

Advantageously, the transition element 24 has a decreasing thickness from the edge 26 in contact with the opaque element 16 towards the display area 18 in order to ensure a substantially continuous and gradual transition between the exterior surface of the opaque element. 16 and the optical surface 10.

This transition lets light pass in the same way as the outer layer 12 so that the image displayed in the display area 18 and in the transition area has the same appearance and the same sharpness.

Advantageously, the transition element 24 and the outer layer 12 have an identical light transmission rate.

According to one embodiment, the opaque element 16 comprises at least one layer 28 of opaque ink (FIG. 3).

According to one embodiment, the transition element 24 comprises at least one layer 30 of translucent ink.

The term “opaque ink” is understood here to mean any opaque composition in liquid form or in gel form, for example colored or tinted with dyes or pigments.

The term “translucent ink” is understood here to mean any translucent composition in liquid form or in gel form. According to one embodiment, the composition is non-colored.

According to one embodiment, the opaque element 16 comprises a number of layers 28 of opaque ink between three and eight, for example four as illustrated in FIG. 3.

Preferably, the opaque element 16 and the transition element 24 comprise the same number of layers 28, 30 respectively of opaque ink and of translucent ink.

Also preferably, the thickness of each layer 30 of translucent ink and the thickness of each layer 28 of opaque ink are identical.

The thickness of each layer 30 of translucent ink and / or the thickness of layer 28 of opaque ink is for example between 0.01 mm and 0.1 mm.

Advantageously, the translucent element 24 comprises at least a first layer 32 of translucent ink and a second layer 34 of translucent ink, the second layer 34 of translucent ink covering part of the first layer 32 of translucent ink. Each layer of translucent ink has, for example, a height of between 1 and 5 μm depending on the viscosity of the material used to make the steps.

The dimension of the second layer 34 of translucent ink, measured in a local direction perpendicular to the opaque element, is less than the corresponding dimension of the first layer 32 of translucent ink. This corresponding dimension of the first layer 32 is for example substantially equal to 20 μm.

In the example shown in FIG. 3, the four layers 30 of translucent ink define a contact surface 36 with the outer layer 12.

The layers 30 define a plurality of steps 29 and risers 31 connecting the steps 29 to each other by an outer edge 33.

This is particularly advantageous since the transition element 24 ensures a less abrupt transition between the opaque zone 14 and the display zone 18, thus avoiding the creation of air bubbles at the interface between the external layer 12 , the optical surface 10 and the opaque element 16 because the external layer 12 is capable of being applied to the entire external surface of the transition element 24 without leaving a void devoid of material between the opaque element 16 and the layer external 12.

The average slope of the contact surface 36 with the outer layer 12 in the local direction perpendicular to the opaque element 16 is for example between 45 degrees and 2 degrees, for example 5 degrees.

The average slope of the contact surface 36 is defined as the inclination relative to the horizontal of a plane defined by the outer edges 33 or of a mean plane defined by the outer edges 33, for example obtained by regression by least squares.

The display device 200 comprises for example a second optical surface deposited on the external layer 12.

The outer layer 12 ensures the adhesion of the second optical surface.

The second optical surface is for example a translucent protective surface making it possible to protect the display device 200 from bumps and scratches. Furthermore, the second optical surface can also be a tinted surface which is opaque when it is not lit and is translucent when it is lit, for example, a tinted window.

A method of manufacturing a display device 200 as detailed above will now be described, in particular with reference to FIG. 3.

The method comprises a step of positioning the translucent transition element 24 disposed on the optical surface 10, between the opaque zone 14 and the display zone 18, the transition element 24 extending from the edge 20 in contact with the opaque element 16 towards the display area 18.

Preferably, the step of placing the transition element 24 comprises depositing at least one layer 30 of translucent ink in contact with the opaque element 16.

Advantageously, the transition element 24 and / or the opaque element 16 are formed by superposition of a plurality of layers 30, 28 of translucent and opaque ink respectively.

The layers 30, 28 are superimposed for example by additive manufacturing using a deposition device 38, shown diagrammatically in FIG. 3.

The deposition device 38 comprises for example a main body 40 and a support (not shown) intended to receive the first optical surface 10.

The main body 40 is for example movable in translation relative to the support in a direction or several directions substantially parallel to the plane in which the support extends.

As a variant, the main body 40 is fixed and the support is movable in translation relative to the main body 40.

The main body 40 comprises at least one deposition nozzle 42 adapted to deposit a layer 28 of opaque ink on the first optical surface 10, and at least one deposition nozzle 44 adapted to deposit a layer 30 of translucent ink on the first optical surface 10.

Preferably, the main body 40 also comprises at least one deposition nozzle (not shown) of a translucent compound, for example liquid or in the form of a gel, suitable for depositing at least one external layer 12 on the optical surface 10.

Preferably, the main body 40 also comprises a polymerization module 46 suitable for polymerizing the layer 28 of opaque ink and / or the layer 30 of translucent ink and / or the external layer 12 in order to fix and harden these.

For example, the polymerization module 46 comprises an element emitting ultraviolet radiation oriented towards the support, for example an ultraviolet lamp or a light-emitting diode (LED) with ultraviolet rays.

The depositing device 38 is preferably controlled by a computer (not shown).

Preferably, the method comprises the successive deposition on the optical surface 10 of a first layer 48 of opaque ink of the opaque element 16 and of the first layer 32 of translucent ink of the transition element 24.

Thus, the first layer 48 of opaque ink and the first layer 32 of translucent ink are deposited on the optical surface 10 in a single pass from the main body 40 of the deposition device 38.

Advantageously, each of the first layer 48 of opaque ink and first layer 32 of translucent ink are polymerized as they are deposited by the polymerization module 46.

Thus, the first layer 48 of opaque ink and the first layer 32 of translucent ink are solidified before a second layer 50 of opaque ink and that the second layer 34 of translucent ink are deposited respectively on the first layer 48 opaque ink and the first layer 32 of translucent ink, according to the same process.

The steps of depositing layers 28, 30 are repeated until the opaque element 16 and the transition element 24 are fully formed.

The method then comprises the deposition of at least one external layer 12.

Preferably, in the case where the outer layer 12 is formed of a liquid adhesive or in the form of a gel, the method comprises the deposition of a plurality of outer layers 12.

According to a particular embodiment, the deposition of the external layers 12 is advantageously carried out by additive manufacturing using the deposition device 38, by depositing a succession of external layers on the assembly formed by the optical surface 10, the element opaque 16 and the transition element 24.

Advantageously, each outer layer 12 is polymerized after its deposition with the polymerization module 46 in a similar manner to that which has been described previously.

Thus, the device 200 according to the invention and its associated manufacturing method are particularly advantageous since the transition element 24 provides a less abrupt transition between the opaque element 16 and the optical surface 10, which makes it possible to avoid creation air bubbles when the outer layer 12 is deposited on the optical surface 10. Thus, the quality of the image displayed by the display device is improved.

The manufacturing process for the display device 200 does not require an additional heating and pressurizing step in an autoclave. The manufacturing process is thus faster.

Finally, the method is particularly advantageous since the steps of placing the opaque element 16, the transition element 24 and depositing the external layer 12 are carried out with a single deposition device 38.

According to an alternative embodiment, the transition element 24 is an added element. The added element is for example a prism with a right triangle base.

The attached element is for example fixed by bonding in contact with the opaque element 16 and the optical surface 10.

Advantageously, the insert and the outer layer 12 have an identical light transmission rate.

Claims (11)

1Display device (200) comprising: - an optical surface (10), - at least one outer layer (12) covering at least part of the optical surface (10), - at least one opaque zone (14) comprising an opaque element (16) disposed between the optical surface (10) and the external layer (12), - at least one translucent display area (18) delimited by at least one edge (20) of the opaque element (16), characterized in that the display device (200) comprises a transition element (24) translucent disposed on the optical surface (10), the transition element (24) extending towards the display area (18) from an edge (26) in contact with the opaque element (16). 2, - display device (200) according to claim 1, wherein the transition element (24) has a decreasing thickness from the edge (26) in contact with the opaque element (16) towards the area of display (18). 3. - Display device (200) according to claim 1 or 2, wherein the opaque element (16) and the transition element (24) respectively comprise at least one layer (28) of opaque ink and at at least one layer (30) of translucent ink. 4, - display device (200) according to any one of claims 1 to 3, wherein the transition element (24) comprises at least a first layer (32) of translucent ink and a second layer (34 ) translucent ink, the second layer (34) of translucent ink covering part of the first layer (32) of translucent ink. 5. - display device (200) according to claim 4, in which, in a local direction perpendicular to the opaque element (16), a dimension of the second layer (34) of translucent ink is less than a dimension of the first layer (32) of translucent ink. 6. - Display device (200) according to any one of claims 3 to 5, in which the opaque element (16) and the transition element (24) comprise the same number of layers (28, 30) opaque ink and translucent ink respectively. 7. - Display device (200) according to any one of claims 3 to 6, in which the thickness of the layer (30) of translucent ink and the thickness of the layer (28) of opaque ink are the same. 8. - Display device (200) according to any one of claims 3 to 7, in which the thickness of the layer (30) of translucent ink and / or the thickness of the layer (28) of opaque ink is between 0.01 mm and 0.1 mm. 9. - Method of manufacturing a display device (200) comprising: - an optical surface (10), - at least one outer layer (12) covering at least part of the optical surface (10), - at least one opaque zone (14) comprising an opaque element (16) disposed between the optical surface (10) and the external layer (12), - at least one translucent display area (18) delimited by at least one edge of the opaque element (16), characterized in that the method comprises a step of placing a translucent transition element (24) disposed on the optical surface (10), the transition element (24) extending towards the display area (18) from an edge (26) in contact with the opaque element (16). 10. - A method of manufacturing a display device (200) according to claim 9, in which the step of placing the transition element (24) comprises depositing at least one layer (30) of translucent ink, the method further comprising a step of depositing at least a layer (28) of opaque ink in contact with the layer (30) of translucent ink, the layer (28) of opaque ink forming the opaque element (16). 11. - A method of manufacturing a display device (200) according to claim 10, in which the layer (30) of translucent ink and / or the layer (28) of opaque ink are deposited by an additive manufacturing process.