CH716998A2 - Watch face having a display based on organic light emitting diodes. - Google Patents

Abstract

One aspect of the invention relates to a watch face having a display (10) based on organic light emitting diodes. The display comprises an anode (20), a structured layer of colored resin (16), preferably photosensitive, in contact with the anode. The display further comprises a stack of organic layers (14) in contact with the anode (20) and with the structured layer of colored resin (16). At least one of the organic layers is an electroluminiscent layer. The display also includes a cathode (12) in contact with the stack of organic layers (14). Other aspects of the invention relate to a watch comprising said dial as well as a method of manufacturing said dial.

Description

Technical area

The invention relates to a watch face having a display based on organic light emitting diodes, a watch comprising said watch face and a method of manufacturing a watch face having a display based on organic light emitting diodes.

Technological background

A display based on organic light-emitting diodes ("organic light-emitting diode" (OLED) in English) is composed of several layers of organic materials sandwiched between two electrodes. Light is emitted in one of the layers of organic material when a current passes through it (the display is in a so-called “ON” state). If it is desired to locate the light emitting zones between the two electrodes, an electrically insulating layer, called a passivation layer, is added to one of the electrodes. This passivation layer is transparent. The final rendering of a “bottom emission” type OLED display in the so-called “OFF” state, ie without through-current, is either the color of the cathode (metallic appearance), or completely black. if a circular polarizer is placed on the OLED display.

General description of the invention

A first aspect of the invention relates to a watch dial having a display based on organic light-emitting diodes. The display comprises an anode, a structured layer of colored resin, preferably photosensitive, in contact with the anode. The display further comprises a stack of organic layers in contact with the anode and with the structured layer of colored resin. At least one of the organic layers is an electroluminescent layer. The display also includes a cathode in contact with the stack of organic layers.

[0004] It will be appreciated that the watch face having a display based on organic light emitting diodes can be decorative even when the display is in an "OFF" state. Indeed, the structure of the structured layer of colored resin makes it possible to achieve, p. eg, a pattern in which parts of the cathode are visible, or at least partially visible, and other parts are hidden by the structured layer of colored resin. This is in contrast to the solutions of the prior art in which, in the “OFF” state, only a uniform color is visible (metallic or black if a circular polarizer is placed on the display).

[0005] According to one embodiment, several colored resins, having different colors, can be used to form the structured layer.

[0006] According to one embodiment, the organic layers are semiconductor.

[0007] The structured layer of colored resin can be covered with an electrically insulating layer. By electrically insulating layer is meant a layer formed of materials whose electrical conductivity does not exceed 10 <-8> Siemens / cm. It will be appreciated that covering the structured layer with an electrically insulating layer allows the use of resins which are optionally electrically conductive while retaining a decorative pattern in the "ON" state having high contrast.

[0008] The structured layer of colored resin can comprise vacancies in which the stack of organic layers is in direct contact with the anode. Conduction channels between the anode and the cathode can be created by gaps in the structured layer of colored resin. Typically the thickness of the colored resin layer (s) is between 500 nm and 2 microns.

[0009] According to one embodiment, the cathode is made of aluminum. According to a preferred embodiment, the thickness of the cathode is in the range from 50 nm to 100 nm. Preferably, the cathode is reflective.

The anode can be transparent, and is preferably made of indium-tin oxide (also called ITO layer). The thickness of the anode can be in the range from 100 nm to 200 nm.

The thickness of the organic stack can be in the range from 100 nm to 200 nm.

According to a preferred embodiment, the anode and / or the cathode are structured. It will be appreciated that the structuring allows certain zones to be selectively put in the “ON” state and others in the “OFF” state. It is thus possible to display information on demand, such as the time, the current date, and / or a logo.

[0013] According to one embodiment, a layer digitally printed by inkjet can be added to the transparent electrode.

A second aspect of the invention relates to a watch comprising a watch dial as described above.

A third aspect of the invention relates to a method of manufacturing a watch dial having a display based on organic light-emitting diodes preferably as described above. The method comprises: depositing a structured layer of colored resin on an anode, the colored resin preferably being photosensitive; • depositing a stack of organic layers on the anode and the structured colored resin layer, at least one of the organic layers being an electroluminescent layer; and • the deposition of a cathode on the stack of organic layers.

The deposition of the structured layer of colored resin is carried out by inkjet, by screen printing, by flexography and / or by heliography.

An electrically insulating layer can be deposited on the structured layer of colored resin before the deposition of the stack of organic layers.

The stack of organic layers can be carried out by vacuum evaporation, by vapor deposition and / or by digital printing by jet of one or more organic materials, optionally semiconductors, to be deposited to form the stack .

Brief description of the drawings

Other features and characteristics of the invention will emerge from the detailed description of certain advantageous embodiments presented below, by way of illustration, with reference to the accompanying drawings which show: FIG. 1: a simplified cross section of a watch dial display based on organic light-emitting diodes, according to a preferred embodiment of the invention; Fig.2: a decorative pattern in the “OFF” state of a watch dial display having a display based on organic light-emitting diodes according to one embodiment of the invention; and Fig.3: a decorative pattern of a watch dial display having a display based on organic light emitting diodes according to one embodiment of the invention.

Detailed description of several embodiments of the invention

[0020] FIG. 1 shows a simplified cross section of a watch dial display 10 according to a preferred embodiment of the invention. The display 10 is based on organic light emitting diodes. The display comprises a reflective aluminum cathode 12, a stack of organic layers 14, a structured layer of colored resin 16 (this resin layer being coated with an electrically insulating layer 18 when the resin layer 16 is semiconductor) and a transparent indium tin oxide anode 20 deposited on a glass substrate (not shown). The display is emission down ("bottom emission" in English) in the sense that the light emitted by the stack of organic layers 14 leaves the display 10 through the anode 20 and the substrate.

The cathode 12 and the anode 20 are configured to create a potential difference. This potential difference can induce a current in the case where the material or materials placed between the cathode 12 and the anode 20 are electrically conductive. In particular, the stack of organic layers 14 placed between the cathode 12 and the anode 20 is conductive or semiconductor, thus allowing current to pass through the stack. At least one of the layers of the stack of organic layers 14 is electroluminescent. The light emission from the electroluminescent layer is the result of the radiative recombination of electrons and the holes forming the current in said electroluminescent layer. The wavelength emitted by the electroluminescent layer depends among other things on the material of the electroluminescent layer.

As indicated above, the display comprises a structured layer of colored resin 16 coated with an electrically insulating layer 18. The electrically insulating layer 18 prevents the passage of a current between the cathode and the anode. Thus, no current is present in the areas comprising the electrically insulating layer 18. It should be noted that it is not necessary to coat the colored resin with an electrically insulating layer over its entire surface. Only the areas which would be in direct contact with the stack are to be coated (see Fig. 1). The colored resin can, in addition to being decorative (that is to say forming an interior decoration to the display), perform the function of the electrically insulating layer 18 in the case where the latter is itself electrically insulating.

The structured layer of colored resin 16 is structured so as to include gaps 24 in which the stack of organic layers is in direct contact with the anode 20 (see FIG. 1). Vertical conduction channels are created between anode 20 and cathode 12 by vacancies 24. Therefore, localized areas of light emission are created in the display.

The structuring of the colored resin layer 16 can make it possible to provide displays with decorative patterns visible both in the “OFF” state (without light emission) and in the “ON” state (with light emission). Fig. 2 shows, for example, a display showing skyscrapers in New York in the “OFF” state. The areas shown as black are areas covered with a black resin. Areas shown white (eg windows) are areas devoid of resins (gaps) making the cathode visible. Since the cathode is reflective, the incident light arriving in the zones revealing the cathode is reflected towards the user of the watch and gives a metallic appearance. In the “ON” state, the resin-free areas are traversed by a current and are illuminated by the emission of light in the electroluminescent layer.

The thickness of the cathode 12 is in the range from 50 nm to 100 nm. The thickness of the anode 20 is in the range from 100 nm to 200 nm. The thickness of the stack 14 is in the range from 100 nm to 200 nm. The thickness of the layers 16 and 18 are each between 500 nm and 1 micron.

The cathode 12 and / or the anode 20 can be structured. In this case, it is possible to selectively switch on certain display areas (only certain display areas are then in the "ON" state). The control of the zones to be lit or not can be carried out by means of a control circuit. In this way, it is possible to display information, such as the current time or date. Fig. 3 shows such a case. The number "23" is displayed by a current flow while no current passes through the rest of the decorative pattern (there is no light emitted at the windows). The windows remain clearly visible even if no light is emitted from them.

An exterior decoration D can be arranged on the surface 26, which is on the user's side, of a substrate 28 carrying the display 10, the latter being covered with an insulating coating material 30. The decor D is typically applied by printing, for example by inkjet printing. Alternatively, the decoration can be deposited on the surface 26 by screen printing, by pad printing, by flexography and / or by heliography.

According to an alternative embodiment, the display 10 illustrated in FIG. 1 could be with emission up ("top emission" in English). This embodiment differs from the embodiment illustrated in FIG. 1 in that the cathode is transparent and the anode is reflective.

The dial manufacturing process as described above comprises the following successive steps: the deposition and structuring of the anode 20 on the glass substrate, the deposition and structuring of a colored resin layer on the anode, the deposition and structuring of an electrically insulating layer on the structured layer of colored resin, the deposition and structuring of a stack of organic layers on the anode and the structured colored resin layer (at least one organic layers is an electroluminescent layer) and the deposition of a cathode on the stack of organic layers.

The deposition and the structuring can be carried out by photolithography, by inkjet, by screen printing, by flexography and / or by heliography. The resin is preferably photosensitive for deposition and structuring by photolithography.

The deposition of the stack of organic layers can be carried out by vacuum evaporation, by vapor deposition and / or by digital printing by jet of one or more materials, optionally semiconductors, organic to be deposited to form stacking.

While particular embodiments have just been described in detail, those skilled in the art will appreciate that various modifications and alternatives to these can be developed in light of the overall teaching provided by the present disclosure of invention. Therefore, the specific arrangements and / or methods described herein are intended to be given by way of illustration only, without the intention of limiting the scope of the invention.

Claims (18)

1. A watch face having an organic light emitting diode based display, the display comprising: an anode; a structured layer of colored resin in contact with the anode; a stack of organic layers in contact with the anode and with the structured layer of colored resin, at least one of the organic layers being an electroluminescent layer; and a cathode in contact with the stack of organic layers. 2. Watch dial according to claim 1, wherein the structured layer of colored resin is covered by an electrically insulating layer. 3. Watch dial according to any one of claims 1 to 2, wherein the structured layer of colored resin comprises vacancies in which the stack of organic layers is in direct contact with the anode. 4. Watch dial according to any one of claims 1 to 3, wherein conduction channels between the anode and the cathode are created by gaps in the structured layer of colored resin. 5. Watch dial according to any one of claims 1 to 4, wherein the cathode is reflective. 6. Watch dial according to any one of claims 1 to 5, wherein the cathode is made of aluminum. 7. Watch dial according to any one of claims 1 to 6, wherein the thickness of the cathode is in the range from 50 nm to 100 nm. 8. Watch dial according to any one of claims 1 to 7, wherein the anode is made of indium tin oxide. 9. Watch dial according to any one of claims 1 to 8, wherein the thickness of the anode is in the range from 100 nm to 200 nm. 10. Watch dial according to any one of claims 1 to 9, wherein the thickness of the stack is in the range from 100 nm to 200 nm. 11. Watch dial according to any one of claims 1 to 10, wherein the anode and / or the cathode are structured. 12. Watch dial according to any one of claims 1 to 11 wherein the thickness of the structured layer of colored resin in contact with the anode is between 500 nm and 1 micron. 13. Watch dial according to one of claims 2 to 12 wherein the thickness of the electrically insulating layer is between 500 nm and 1 micron. 14. Watch dial according to any one of the preceding claims, in which a decoration D is disposed on the surface of a substrate carrying the display, said surface being disposed on the side visible to the user. 15. Watch comprising a watch face according to any one of claims 1 to 14. 16. A method of manufacturing a watch face having a display based on organic light-emitting diodes comprising: depositing a structured layer of colored resin on an anode; depositing a stack of organic layers on the anode and the structured colored resin layer, at least one of the organic layers being an electroluminescent layer; and the deposition of a cathode on the stack of organic layers. 17. The method of claim 14, wherein the deposition of the structured layer of colored resin is carried out by photolithography, by inkjet, by screen printing, by flexography and / or by heliography. 18. The method according to any one of claims 16 to 17, wherein an electrically insulating layer is deposited on the structured layer of colored resin before the deposition of the stack of organic layers.