Method for manufacturing display screen

Abstract

The invention relates to a method for manufacturing a color electronic display screen (10), said color electronic display screen (10) comprising an active unit (11) and at least one polarizing film (114), said polarizing film (114) comprising an optical layer (115) and a colored adhesive layer (116), said polarizing film (114) being bonded to said active unit (11) via said adhesive layer (116).

Description

Technical Field

[0001] The present invention relates to display screens, and more particularly to the field of electronic display screens. More specifically, the present invention relates to a method for manufacturing such a display screen. Background Art

[0002] There are many electronic display screen technologies, including liquid crystal displays which are very commonly used in all types of applications.

[0003] The liquid crystal display screen can be a raster scan display or a segmented display, and includes a liquid crystal cell, on both sides of which optical films, particularly polarizing films and color films, are arranged to endow the display screen with a given color.

[0004] Introducing color filters into the cell has many drawbacks.

[0005] More specifically, since its thickness can reach 100 μm, in some application fields of liquid crystal display screens where the goal is to miniaturize the component size as much as possible, such as in the watchmaking industry, color filters may be particularly redundant.

[0006] In addition, the color selection of color filters is limited, which restricts the aesthetic possibilities of the final product, and the manufacture of these color filters is not suitable for small batch production, which has a significant impact on the production cost depending on the number of color filters to be considered. For example, when the liquid crystal display screen is small, such as in the watchmaking industry, such small batch production is required. Summary of the Invention

[0007] The present invention overcomes the above drawbacks, and for this purpose, relates to a method for manufacturing a color electronic display screen as described above, the method comprising:

[0008] - a step of obtaining a polarizing film comprising an optical layer, with an adhesive layer extending on the optical layer,

[0009] - a step of dyeing the adhesive layer, and then

[0010] - a step of bonding the polarizing film to an active cell by means of the adhesive layer.

[0011] In a specific embodiment, the dyeing step comprises immersing the polarizing film in a dye bath so that the content of the bath diffuses into the adhesive layer.

[0012] In a specific embodiment, the dyeing step successively comprises an operation of dip-coating the polarizing film, an operation of rinsing the polarizing film, an operation of drying the polarizing film, and an operation of cutting the polarizing film to have a given size.

[0013] In a specific embodiment, the dip-coating operation is carried out for 10 to 60 seconds.

[0014] In certain embodiments, the drying operation is carried out by forced ventilation or by firing. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In reference Figure 1 Upon reading the following detailed description given by way of example and not limitation, other features and advantages of the present invention will become apparent. Figure 1 Figure 1 shows a cross-sectional view of a color electronic display screen in accordance with a preferred example of the present invention.

[0016] It should be noted that, for clarity, the drawings are not drawn to scale. DETAILED DESCRIPTION

[0017] Figure 1 An exemplary application of the color electronic display screen 10 according to the present invention is shown, wherein the electronic display screen 10 is formed by a liquid crystal display (LCD). It should be noted that the present invention can be applied to any type of electronic display screen, such as a display screen including at least one organic light emitting diode (OLED).

[0018] The object of the present invention is to impart a given monochromatic coloring to the display screen that is stable over time.

[0019] The electronic display screen 10 includes active units 11, which are formed by a liquid crystal cell for a segmented display in the exemplary embodiment shown in Figure 1 This liquid crystal cell is defined in a manner known per se to those skilled in the art between two substrates 110 made of, for example, glass or plastic material, with transparent electrodes 111 fixed to each substrate, and the two electrodes 111 are separated by a sealing frame 112 enclosing the liquid crystal 113.

[0020] It should be noted that the present invention can also be applied to liquid crystal display screens intended to display raster images.

[0021] The electronic display screen 10 includes at least one polarizing film 114, which includes an optical layer 115, and a colored adhesive layer 116 extends on the optical layer 115. The polarizing film 114 is adhered to the active unit 11 via the adhesive layer 116. The adhesive layer 116 is also known by the acronym "OCA" for "optically clear adhesives" and is made of, for example, an acrylic adhesive.

[0022] In particular, in Figure 1In the exemplary embodiment shown, a polarizing film 114 is adhered to each substrate 110 of the active unit 11. The two adhesive layers 116 attached to the polarizing film 114 may be colored to increase the intensity of the color or to be closer to the perceived target color.

[0023] As used herein, as Figure 1 schematically shown, the relative terms "front" and "rear" respectively refer to the position of the elements of the electronic display screen 10 relative to the user when the user views the display.

[0024] The electronic display screen 10 thus includes a front polarizing film 114 and a rear polarizing film 114 adhered respectively through the front adhesive layer 116 and the rear adhesive layer 116. The rear adhesive layer 116 may be configured to have a light scattering ability.

[0025] As Figure 1 can be seen, the electronic display screen 10 further includes a back layer 117, for example black, which is adhered to the rear polarizing film 114 by means of a back adhesive layer 118.

[0026] Needless to say, all the adhesive layers of the present invention are transparent or at least translucent.

[0027] The color electronic display screen 10 is manufactured using a method including the steps of obtaining a polarizing film 114 on which the adhesive layer 116 extends, dyeing the adhesive layer 116, and then adhering the polarizing film 114 to the active unit 11 via the adhesive layer 116. These steps can be performed on multiple polarizing films 114 of the same electronic display screen 10.

[0028] The step of dyeing the adhesive layer 116 may include dipping the polarizing film 114 on which the adhesive layer 116 is deposited in a dye bath so that the contents of the bath diffuse into the adhesive layer 116. The bath may consist of an aqueous solution, a solvent and an acrylic pigment. Generally, within the ability of those skilled in the art, the bath may consist of a composition suitable for dyeing plastic materials. Advantageously, after the dyeing step, the adhesive layer 116 retains its adhesive properties. In addition, the dyeing step has the advantage of not affecting the thickness of the polarizing film 114.

[0029] In addition, the dyeing step may more specifically successively include the operations of dip-coating the polarizing film 114, rinsing the polarizing film 114, drying the polarizing film 114 and cutting the polarizing film 114 so that the polarizing film 114 has a given shape and size.

[0030] For example, the dip coating operation is carried out for 10 to 60 seconds, preferably between 30 and 45 seconds. It should be noted that the color intensity of the polarizing film 114 is proportional to the duration of the dip coating operation. This dip coating operation can be carried out cold, i.e., in a bath at ambient temperature, or it can be carried out hot, i.e., in a bath at a temperature higher than 50 °C. Carrying out the dip coating operation hot advantageously enables the color to be distributed more evenly and more quickly on the polarizing film 114.

[0031] In addition, the drying operation can be carried out using forced ventilation or by baking in an oven, for example, baking at 70 °C for 5 minutes.

[0032] More generally, it should be noted that the implementations and embodiments considered above have been described by way of non-limiting examples, and thus other alternatives are possible.

[0033] Advantageously, the present invention does not increase the thickness of the electronic display screen 10 because it eliminates the need for an additional color film. The present invention also enables fine control of the color of the electronic display screen 10 because controlling the composition of the bath, the dip coating time, and the bath temperature during the dip coating operation or even the combination of the dyeing of at least two polarizing films are all that is required to obtain the desired color.

Claims

1. A method for manufacturing a color electronic display screen (10), the method comprising: A step of obtaining a polarizing film (114) comprising an optical layer (115), an adhesive layer (116) extending on the optical layer (115), a step of dyeing the adhesive layer (116), and then a step of bonding the polarizing film (114) to an active unit (11) by means of the adhesive layer (116), wherein the dyeing step comprises immersing the polarizing film (114) in a dye bath so that the contents of the bath diffuse into the adhesive layer (116), and the dyeing step successively comprises an operation of dipping the polarizing film (114), an operation of rinsing the polarizing film (114), an operation of drying the polarizing film (114), and an operation of cutting the polarizing film (114) to have a given size. 2 . The manufacturing method according to claim 1 , wherein the dipping operation is performed for 10 to 60 seconds.

3. The manufacturing method according to claim 1, wherein the drying operation is performed by forced ventilation or by baking.

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