Method for manufacturing digital display device and digital display device

Abstract

The invention relates to a method for producing a digital display device, the digital display device comprising an optically active medium arranged between at least one electrode (10) and at least one corresponding counter-electrode (14), the optical properties of the optically active medium being modifiable by applying a current or a voltage between the at least one electrode (10) and the at least one corresponding counter-electrode (14), the digital display device comprising a transparent display surface (34) through which at least one item of information displayed by the digital display device can be seen, the method comprising the step of providing the transparent display surface (34) of the digital display device with at least one first decorative and / or functional pattern (36) and at least one second decorative and / or functional pattern (38), the first pattern (36) having a thickness different from that of the second pattern (38). The invention also relates to a timepiece and a digital display device.

Description

Technical Field

[0001] The present invention relates to a manufacturing method of a digital display device and a digital display device, and more particularly to a manufacturing method for providing a decorative and / or functional pattern for a digital display device. Background Art

[0002] The present invention focuses on display devices of the digital type, that is to say display devices capable of displaying information in alphanumeric form, as opposed to analog display devices which display information by means of one or more pointers moving next to a scale.

[0003] A well-known family of digital display devices includes liquid crystal display devices. These liquid crystal display devices generally comprise a transparent front substrate, situated on the viewer's side, and a transparent or opaque rear substrate, extending parallel to and away from the front substrate. The two front and rear substrates are generally connected together by a sealing frame, which defines a tight enclosure in which the liquid crystal composition is confined. Finally, the front and rear substrates are coated on their opposite faces with conductive transparent electrodes and counter-electrodes; by applying an electric field between an electrode and a corresponding counter-electrode, the optical properties of the liquid crystal composition are altered at the intersection of the electrode in question and the counter-electrode.

[0004] Another well-known family of digital display devices includes organic light-emitting diode display units, also known as OLEDs. These are monolithic semiconductor components that typically include a series of organic thin films sandwiched between two conductive thin film electrodes. When an electric current is applied to the organic light-emitting diode component, an electric field is generated between the two electrodes, under the action of which charge carriers, electrons and holes, migrate from the electrodes in the organic thin film until they recombine in the emission region by forming excitons, that is, electron-hole pairs bound by Coulomb forces. Once formed, these excitons or excited states relax to lower energy levels by emitting photons (electroluminescence) and heat, thereby generating a light signal that can be seen by the human eye through electrodes arranged on the exit face of the organic light-emitting diode component.

[0005] More generally, therefore, the present invention focuses on digital display devices comprising an optically active medium disposed between at least one electrode and a corresponding counter-electrode, the optical properties of the optically active medium being modifiable by applying a current or voltage between the at least one electrode and at least one corresponding counter-electrode.

[0006] A digital display device of the type briefly described above can be fitted in particular to many wearable objects such as wristwatches, thereby providing an alternative to wristwatches provided with a dial on which hands move.

[0007] Among the advantages offered by digital display devices, one can mention their low weight, extremely low power consumption, or the possibility of displaying information in alphanumeric form, which attracts a large part of consumers, especially the youngest among them.

[0008] However, digital displays, and especially liquid crystal displays, also present some disadvantages, the first of which is their boring and repetitive appearance. With liquid crystal displays, the combination of the look / look, colour, material, shape etc. provided by the dial with hands of a wristwatch really loses a lot. In fact, all digital displays have more or less the same appearance and it is difficult to give, for example, a watch equipped with a liquid crystal display a look that would allow it to be distinguished from competing liquid crystal display watches. Summary of the invention

[0009] The object of the present invention is to overcome the above-mentioned problems and others by providing a method for manufacturing a liquid crystal display device which allows to give such a display device a more original appearance, thereby making it stand out from competing liquid crystal display devices.

[0010] To this end, the present invention relates to a method for manufacturing a digital display device, which includes an optically active medium arranged between at least one electrode and a corresponding counter-electrode, and the optical properties of the optically active medium can be modified by applying an electric current or a voltage between the at least one electrode and the at least one corresponding counter-electrode. The digital display device includes a lower surface and an upper surface, through which at least one information displayed by the digital display device can be seen, and the manufacturing method includes the step of providing the upper surface of the digital display device with at least one first decorative and / or functional pattern and at least one second decorative and / or functional pattern, the thickness of the first pattern being different from the thickness of the second pattern.

[0011] Thanks to these characteristics, the invention provides a manufacturing method that allows obtaining a digital display device, through which the information items generated and displayed by the digital display device can be seen, provided with at least one first pattern and at least one second pattern, the thickness of the at least one first pattern being different from the thickness of the at least one second pattern. These patterns of different thickness form a relief on the surface of the digital display device, giving volume to the surface of the digital display device on which these patterns are arranged, through the effect of shadows on the ridges of the patterns and reflections of ambient light. This impression of volume is further enhanced by the fact that these patterns have different thicknesses, thus giving a sense of variable depth when examining the surface of the digital display device on which these patterns are arranged. Therefore, depending on whether the area in which the first pattern is located or the area in which the second pattern is located is viewed, the observer has the impression that the information items displayed in either of these two areas are not located at the same depth relative to the transparent display surface of the digital display device.

[0012] According to a particular embodiment of the invention, the at least one first pattern and the at least one second pattern are formed directly on the transparent display surface of the digital display device by applying and structuring one or more layers consisting of at least one photosensitive resin.

[0013] According to another particular embodiment of the invention, said one or more layers consisting of at least one photosensitive resin are structured by photolithography.

[0014] According to yet another embodiment of the present invention, the at least one first pattern and the at least one second pattern are directly formed on the transparent display surface of the digital display device in the following manner:

[0015] - depositing a layer of a photopolymerizable resin;

[0016] - replicating at least one first pattern and at least one second pattern in the photopolymerizable resin layer by means of a mold;

[0017] - curing the photopolymerizable resin layer by exposure to light radiation; and

[0018] -Remove resin that has not been exposed to light radiation.

[0019] According to another embodiment of the present invention, the photopolymerizable resin is exposed to ultraviolet radiation.

[0020] According to yet another embodiment of the present invention, the at least one first pattern and the at least one second pattern are produced in relief in a transparent plate, which is then attached to the display surface of the digital display device.

[0021] According to another embodiment of the present invention, the transparent embossed plate is produced by one of the following techniques:

[0022] - by injection of plastic materials;

[0023] - by depositing a photopolymerizable resin layer on a transparent plate, then replicating the at least one first pattern and the at least one second pattern in the photopolymerizable resin layer by means of a mold, then curing the photopolymerizable resin layer by exposing it to light radiation, and finally removing the resin that has not been exposed to the light radiation;

[0024] - by hot stamping of transparent sheets; and

[0025] - Moulding the transparent sheet by using a two-component adhesive in a mould.

[0026] According to yet another embodiment of the present invention, the thickness of the patterns is in the range of 1 micrometer to 1 millimeter.

[0027] According to yet another embodiment of the present invention, the digital display device is a liquid crystal display unit or an organic light emitting diode display unit.

[0028] The invention also relates to a timepiece comprising a digital display device obtained by implementing the method according to the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Other features and advantages of the invention will emerge more clearly from the following detailed description of an embodiment of the method according to the invention, which example is given purely in an illustrative and non-limiting manner in conjunction with the accompanying drawings, in which:

[0030] Figure 1 is a cross-sectional view of a liquid crystal display unit, on the transparent display surface of which first and second patterns of different thicknesses have been provided;

[0031] Figures 2A to 2D The steps of a method for producing first and second patterns by replication using a mold on a photosensitive resin layer are shown;

[0032] Figure 3 yes Figure 1 A cross-sectional front view of a liquid crystal display unit having a transparent plate attached to a display surface thereof and having first and second patterns formed on the transparent plate; and

[0033] Figure 4 is a top view of a wristwatch equipped with a liquid crystal display unit obtained by implementing the method according to the present invention. DETAILED DESCRIPTION

[0034] The invention proceeds from a general inventive concept, which is to provide a transparent display surface of a digital display device, such as a liquid crystal display unit or a display unit with organic diodes, which transparent display surface has at least one decorative and / or functional first pattern and at least one decorative and / or functional second pattern, which differ from each other in that they have different thicknesses. Due to their height difference, these first and second patterns provide the transparent display surface with a relief / concave-convex structure, through which the information generated and displayed by the digital display unit can be seen. In fact, by reflecting on the edges of the first and second patterns, the light changes direction several times, which highlights the height difference between the first and second patterns and gives the impression that the information displayed by the digital display unit is in different planes, thus giving the transparent display surface a more luxurious and refined appearance.

[0035] The invention will be described more specifically in connection with a digital display device of the liquid crystal display unit type. However, it should be understood that the invention is not limited to this particular example and that it is applicable to any type of digital display device provided with such a transparent display surface through which the information generated by the digital display device can be seen. In particular, organic light emitting diode display units are considered.

[0036] exist Figure 1 The liquid crystal display unit shown in front cross-section in the figure and generally indicated by reference numeral 1 comprises a front substrate 2 and a rear substrate 4, which extends parallel to the front substrate 2 and is separated from the front substrate 2 by a certain distance. The front substrate 2 is transparent, through which the information generated and displayed by the liquid crystal display unit 1 can be seen, and the rear substrate 4 can also be transparent or can be opaque. Figure 1 In the example shown, the rear substrate 4 is transparent, and both the front substrate 2 and the rear substrate 4 are made of plastic or glass.

[0037] The front substrate 2 and the rear substrate 4 are usually joined together by a sealing frame 6, which defines a tight enclosure 8 for confining the liquid crystal composition. At least one electrode 10 is constructed on the lower surface 12 of the front substrate 2, and at least one corresponding counter electrode 14 is constructed on the upper surface 16 of the rear substrate 4. By applying an electric field between the at least one electrode 10 and the at least one counter electrode 14, the optical properties of the liquid crystal composition are changed at the intersection of the electrodes in question. A transparent reflective polarizer 18 is attached to the inner surface 22 of the rear substrate, for example, by a transparent adhesive layer 20, and a black film 24 is attached to the transparent reflective polarizer 18, for example, by another transparent adhesive layer 26. Finally, a transparent absorptive polarizer 28 is attached to the upper surface 30 of the front substrate 2, for example, by a further transparent adhesive layer 32.

[0038] The front substrate 2 coated with the transparent absorbing polarizer 28 forms a transparent display surface 34 through which the information generated by the liquid crystal display unit 1 can be seen by the observer. According to the present invention, the transparent display surface 34 of the liquid crystal display unit 1 is respectively provided with at least one decorative and / or functional first pattern 36 and at least one decorative and / or functional second pattern 38, the thickness of the first pattern 36 being different from the thickness of the second pattern 38. The thickness of the first pattern 36 and the second pattern 38 is preferably in the range of 1 micrometer to 1 millimeter.

[0039] According to the first embodiment of the present invention, the first pattern 36 and the second pattern 38 are directly formed on the transparent display surface 34 of the liquid crystal display unit 1 by applying and structuring one or more layers composed of at least one photosensitive resin. The photosensitive resin layer is structured by photolithography. For example, a first resin layer of a first thickness is structured to form the first pattern 36, and then a second resin layer of a second thickness different from the first thickness is structured to form the second pattern 38.

[0040] according to Figure 2A In the second embodiment of the present invention shown in the subsequent figures, the first pattern 36 and the second pattern 38 are directly formed on the transparent display surface 34 of the liquid crystal display unit 1 in the following manner:

[0041] - Deposition of a photopolymerizable resin layer 40 ( Figure 2A );

[0042] - Replicating the first pattern 36 and the second pattern 38 in the photopolymerizable resin layer 40 by means of the mold 42 ( Figure 2B );

[0043] - exposing the photopolymerizable resin layer 40 to light radiation 44 transmitted through the mold 42 to cure the photopolymerizable resin layer 40 ( Figure 2C );as well as

[0044] - Remove the mold 42 ( Figure 2D ).

[0045] As a preferred but non-limiting example, the photopolymerizable resin is exposed to ultraviolet radiation 44 .

[0046] according to Figure 3 In the third embodiment of the present invention shown, instead of forming the first pattern 36 and the second pattern 38 directly on the transparent display surface 34 of the liquid crystal display unit 1, the first pattern 36 and the second pattern 38 may be embossed in a transparent plate 46, and then the transparent plate 46 is attached to the transparent display surface 34, for example, by an optically transparent layer adhesive 48.

[0047] The transparent plate 46 having the embossed first pattern 36 and second pattern 38 can be obtained by one of the following techniques:

[0048] - by injecting the plastic material into the mould;

[0049] - by hot stamping of a transparent starting sheet;

[0050] - Moulding by using a two-component adhesive in the mould;

[0051] - by depositing a photopolymerizable resin layer on a transparent substrate, then replicating the first and second patterns in relief in the photopolymerizable resin layer through a mold, then curing the photopolymerizable resin layer by exposing it to light radiation transmitted through the mold, and finally removing the mold.

[0052] Thus, a liquid crystal display unit 1 is obtained, whose transparent display surface 34 receives the first patterns 36 and the second patterns 38 of different thicknesses directly or through the transparent plate 46. Therefore, when light is reflected on the edges 50 of these first patterns 36 and the second patterns 38, the light changes direction multiple times, which emphasizes the height difference between the first patterns 36 and the second patterns 38 and gives the transparent display surface 34 of the liquid crystal display unit 1 an impression of depth and a more luxurious and refined appearance.

[0053] Figure 4 An example of a wristwatch 52 equipped with a liquid crystal display unit 1 according to the present invention is shown. Figure 4 It can be seen that the transparent display surface 34 of the liquid crystal display unit 1 has a rectangular first display area 54 which provides an indication of the current time, for example on a 24-hour basis. At this time, the first display area 54 indicates to the observer that it is 14 o'clock. The transparent display surface 34 is also provided with an annular second display area 56 which indicates the minutes of the current hour by means of a scale which increases in increments of 5 minutes. In this case, at Figure 4 In the example shown, the movable mark 58 points to indicate "10 minutes". It can therefore be understood that the time indicated by the watch 52 is 14:10. According to the present invention, the first display area 54 is surrounded by the first border 60 at its entire periphery, and the second display area 56 is surrounded by the inner border 62a and the outer border 62b concentric with each other at its entire circumference. According to the present invention, the first border 60 is thicker than the inner border 62a and the outer border 62b, in other words, higher. The effect of multiple reflections of light on the edges of the borders 62a, 62b enables the display areas 54 and 56 to obtain a depth effect, wherein the second display area 56 is felt to be at a lower height than the first display area 54.

[0054] It goes without saying that the invention is not limited to the embodiment that has just been described, and various modifications and simple variations of the invention may be considered without departing from the scope of the invention as defined by the appended claims. In particular, it should be understood that, although the invention has been described in conjunction with a liquid crystal display unit, it goes without saying that the invention is not limited to this single example and that the invention is applicable to other types of digital display devices, for example, in particular a display unit with an organic light-emitting diode, which may also have at least one first pattern and at least one second pattern on its transparent display surface, the first pattern and the second pattern having different thicknesses. It should also be understood that, although in the example described, the first and second patterns are constructed on a transparent absorptive polarizer attached to the upper surface of the front substrate of the liquid crystal display unit, this example is given in a purely illustrative and non-limiting manner, and these patterns may be constructed on, for example, a transparent plate that is then attached to the polarizer. It should also be understood that in order to produce an optical effect associated with the reflection of ambient light and to obtain the desired sense of depth, at least two patterns of different thicknesses are required, however, the number of these patterns may be much greater than 2. It should also be understood that it is necessary to ensure that the patterns are properly aligned relative to the display area of ​​the digital display device. These patterns can also be made into repeated relief structures to imitate the dial finishes encountered in the field of watchmaking, such as brushed dials, Clous De Paris or brushed sun-brushed finishes. These patterns are made by applying and structuring one or more layers consisting of at least one photosensitive resin. It is also interesting to polish the upper surface of the pattern so as to enhance the reflection of ambient light on these patterns, thereby giving more volume to the transparent display surface of the digital display device by highlighting some areas of the display surface that are transparent relative to other areas. It should also be understood that the more reflective the transparent display surface is, the higher its optical refractive index. The pattern can also be combined with an anti-glare treatment of the transparent display surface or transparent plate. These anti-glare treatments are, for example, of the "moth eye" type and are obtained by nano-structuring or micro-structuring the transparent display surface or the transparent plate. Another technology that can be used to make the pattern is inkjet printing, also known as digital printing. Depending on the thickness of the desired pattern, one or more layers of ink are applied and then air-dried, or dried. The deposited ink can also be photopolymerized.

[0055] Reference numerals list

[0056] 1. Liquid crystal display unit

[0057] 2. Front base plate

[0058] 4. Rear substrate

[0059] 6. Sealing frame

[0060] 8. Sealed housing

[0061] 10. Electrodes

[0062] 12. Lower surface

[0063] 14. Counter electrode

[0064] 16. Upper surface

[0065] 18. Transparent reflective polarizer

[0066] 20. Transparent adhesive layer

[0067] 22. Lower surface

[0068] 24. Black film

[0069] 26. Transparent adhesive layer

[0070] 28. Transparent Absorbing Polarizer

[0071] 30. Upper surface

[0072] 32. Transparent adhesive layer

[0073] 34. Transparent display surface

[0074] 36. The first pattern

[0075] 38. Second pattern

[0076] 40. Photopolymerizable resin layer

[0077] 42. Mould

[0078] 44. Light Radiation

[0079] 46. ​​Transparent board

[0080] 48. Adhesive layer

[0081] 50. Edge

[0082] 52. Watches

[0083] 54.First display area

[0084] 56. Second display area

[0085] 58. Removable Marker

[0086] 60. The First Border

[0087] 62a. Inner Boundary

[0088] 62b. Outer boundary

Claims

1. A method for manufacturing a digital display device, the digital display device comprising an optically active medium arranged between at least one electrode (10) and at least one corresponding counter electrode (14), the optical properties of the optically active medium being modifiable by applying a current or a voltage between the at least one electrode (10) and the at least one corresponding counter electrode (14), the digital display device comprising a transparent display surface (34) through which at least one item of information displayed by the digital display device can be seen, the method comprising the steps of providing the transparent display surface (34) of the digital display device with at least one first decorative and / or functional pattern (36) and at least one second decorative and / or functional pattern (38), the thickness of the first pattern (36) being different from the thickness of the second pattern (38), in, The at least one first pattern (36) and the at least one second pattern (38) are formed directly on the transparent display surface (34) of the digital display device by applying and structuring one or more photosensitive resin layers composed of at least one photosensitive resin, and The one or more photosensitive resin layers composed of at least one photosensitive resin are constructed by photolithography, and the thickness of the at least one first pattern (36) and the at least one second pattern (38) is in the range of 1 micrometer to 1 millimeter.

2. The manufacturing method according to claim 1, characterized in that: The at least one first pattern (36) and the at least one second pattern (38) are directly formed on the transparent display surface (34) of the digital display device by: - depositing at least one layer of photopolymerizable resin (40); - replicating at least one first pattern (36) and at least one second pattern (38) in the photopolymerizable resin layer (40) by means of a mold (42); - curing the photopolymerizable resin layer (40) by exposing the photopolymerizable resin layer (40) to light radiation (44) transmitted through the mold (42); as well as - Removing the mould (42).

3. The manufacturing method according to claim 2, characterized in that: The photopolymerizable resin layer (40) is exposed to ultraviolet radiation.

4. The manufacturing method according to claim 1, characterized in that: The manufacturing method comprises the steps of manufacturing the at least one first pattern (36) in relief and the at least one second pattern (38) in relief in a transparent plate (46), and then attaching the transparent plate (46) to a transparent display surface (34) of the digital display device by means of an optically clear adhesive layer (48).

5. The manufacturing method according to claim 4, characterized in that: The transparent plate (46) with the relief is produced by one of the following techniques: - by injection of plastic materials; - by depositing a photopolymerizable resin layer on a starting transparent plate, then replicating the at least one first pattern and the at least one second pattern in the photopolymerizable resin layer by means of a mold, then curing the photopolymerizable resin layer by exposing it to light radiation transmitted through the mold, and finally removing the mold; - starting transparent sheet by hot stamping; - molding the transparent sheet by using a two-component adhesive in a mold; and -By inkjet printing.

6. The manufacturing method according to any one of claims 1 to 5, characterized in that: The digital display device is a liquid crystal display unit (1) or an organic light emitting diode display unit.

7. The manufacturing method according to any one of claims 1 to 5, characterized in that: The at least one first pattern (36) and the at least one second pattern (38) are made into a repeating relief structure to simulate brushed, brushed sunray, Paris hobnail, cork and woven watch dial finishes.

8. The manufacturing method according to any one of claims 1 to 5, characterized in that: The upper surface of the at least one first pattern (36) and the upper surface of the at least one second pattern (38) are polished.

9. The manufacturing method according to claim 4, characterized in that: The at least one first pattern (36) and the at least one second pattern (38) are combined with an anti-glare treatment of the transparent display surface (34) or the transparent plate (46).

10. The manufacturing method according to claim 9, characterized in that: The anti-glare treatment is obtained by performing nano-structuring treatment or micro-structuring treatment on the transparent display surface (34) or the transparent plate (46).

11. A timepiece comprising a digital display device obtained by implementing the manufacturing method according to any one of the preceding claims.

12. A digital display device comprising an optically active medium disposed between at least one electrode (10) and at least one corresponding counter electrode (14), the optical properties of the optically active medium being modifiable by applying a current or voltage between the at least one electrode (10) and the at least one corresponding counter electrode (14), the digital display device comprising a transparent display surface (34), through which at least one item of information displayed by the digital display device can be seen, the transparent display surface (34) being coated with at least one first decorative and / or functional pattern (36) and at least one second decorative and / or functional pattern (38), the thickness of the first pattern (36) being different from the thickness of the second pattern (38), the at least one first pattern (36) and the at least one second pattern (38) being both formed directly on the transparent display surface (34) of the digital display device, and the thickness of the at least one first pattern (36) and the at least one second pattern (38) being in the range of 1 micrometer to 1 millimeter.

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