Electronic paper display

Abstract

Electronic paper display (100), with: a thin-film transistor layer (101) which is bounded by an end wall (107); a reflective ink layer (103) which is arranged above the thin-film transistor layer (101), wherein the ink layer (103) is bounded by an end wall (105); a light-transparent cover (109) which is arranged above the ink layer (103), wherein the light-transparent cover (109) has a flat underside (111) which faces the ink layer (103); and a seal (113) which at least partially covers the end wall (107) of the thin-film transistor layer (101) and the end wall (105) of the ink layer (103) and is bonded to the flat underside (111) of the light-transparent cover (109) in a flat and materially bonded manner.

Description

[0001] The present invention relates to an Electronic Paper Display (EPD).

[0002] The patent application US 2010 / 0 327 737 A1 describes an electro-optical device.

[0003] The translation DE 699 18 308 T2 of the European patent EP 1 105 772 B1 describes an electronic display based on organic field-effect transistors.

[0004] Disclosure US 2013 / 0 222 725 A1 describes a liquid crystal display.

[0005] Disclosure document US 2015 / 0 360 606 A1 describes an LED film.

[0006] Modern EPDs are typically used to display text such as books. The text content is usually displayed using a reflective ink layer, which is controlled by a thin-film transistor layer (TFT; Thin Film Technology) that is typically located underneath.

[0007] An EPD (Electronic Product Declaration) is structured in layers, with further layers arranged on top of each other. The ink layer is typically covered by a protective layer, which may also include a backlighting layer with light elements such as OLEDs. A touch-sensitive layer may be placed on top of the backlighting layer, covered by a transparent cover, usually made of plastic. The light emitted by the backlighting layer is reflected by the ink layer and is visible through the transparent cover.

[0008] The ink layer of an EPD must be sealed against humidity. This is achieved, among other things, by the protective layer directly on the EPD, possibly in conjunction with the thin-film transistor layer beneath it. Additionally, a sealing adhesive is used, which adheres to the thin-film transistor layer and protects the protective layer, along with the ink layer, from moisture penetration. For this to work, however, the ink layer must be shorter than the thin-film transistor layer so that the sealing adhesive can be applied across its entire surface. Shortening the ink layer reduces the size of the display area formed by the ink layer. Furthermore, the thin-film transistor layer becomes larger than necessary, increasing manufacturing costs.

[0009] It is therefore the object of the present invention to design the seal in such a way that the ink layer does not have to be shortened relative to the thin-film transistor layer.

[0010] This problem is solved by the features of the independent claims. Advantageous embodiments of the invention are the subject of the dependent claims, the description, and the accompanying figures.

[0011] The invention is based on the finding that the above problem can be efficiently solved by attaching the seal to the light-transparent cover of an EPD. The light-transparent cover is generally somewhat larger, and in particular somewhat longer, than the ink layer. Furthermore, the light-transparent cover is less expensive to manufacture than the thin-film transistor layer.

[0012] The sealant or sealing compound is bonded to the flat underside of the translucent cover, creating a strong and stable bond. The sealing structure is reversed compared to the prior art, as the sealant extends from the cover down to the thin-film transistor layer. This allows for optimal dimensioning of the thin-film transistor layer. Furthermore, the size of the ink layer, particularly its length, can be adapted to the size or length of the thin-film transistor layer. This enables an increased display size without compromising the sealing effect against moisture. This also offers the advantage of allowing for a thinner frame surrounding the cover.

[0013] According to a first aspect, the invention relates to an electronic paper display comprising: a thin-film transistor layer; a reflective ink layer arranged above the thin-film transistor layer, wherein the ink layer is bounded by an end wall; a light-transparent cover arranged above the ink layer, wherein the light-transparent cover has a flat underside facing the ink layer; and a seal which at least partially covers the end wall of the thin-film transistor layer and the end wall of the ink layer and is bonded to the flat underside of the light-transparent cover in a planar and metallurgically bonded manner.

[0014] The seal can be made from an elastic and / or thermodeformable plastic, such as silicone or elastomer. A subgroup of elastomers are thermoplastic elastomers (TPE) or cross-linked thermoplastic elastomers (TPV). Examples of such thermoplastic elastomers include a mixture of polypropylene and ethylene propylene diene monomer (EPDM), syndiotactic polystyrene (SPC), and styrene-butadiene polyethylene styrene (SPE). However, the seal can also be created using an adhesive.

[0015] The sealant extends over several, and in particular all, layers of the EPD. This results in a particularly effective seal against moisture. Furthermore, the end-face bonding of the EPD layers to the sealant improves the stability of the EPD, as the sealant provides a counter-bearing surface for the stacked layers.

[0016] In one embodiment, the seal partially or completely covers the end wall of the thin-film transistor layer.

[0017] In one embodiment, the seal completely covers the end wall of the ink layer.

[0018] In one embodiment, the reflective ink layer is arranged on the thin-film transistor layer, in particular directly.

[0019] In one embodiment, the electronic paper display comprises a protective layer arranged on the reflective ink layer, wherein the protective layer has an end wall, and wherein the seal covers the end wall of the protective layer.

[0020] In one embodiment, the protective layer and the thin-film transistor layer are of the same size, in particular of the same length, within a tolerance range, for example 1%, 2% or 5%.

[0021] In one embodiment, the electronic paper display comprises an illumination layer which is arranged above the ink layer, in particular on a protective layer, wherein the illumination layer has a plurality of light sources, in particular OLEDs, which are configured to illuminate the reflective ink layer, wherein the illumination layer is bounded by an end wall, and wherein the seal covers the end wall.

[0022] In one embodiment, the electronic paper display comprises a touch-sensitive layer which is arranged above the ink layer, in particular on a illumination layer, wherein the touch-sensitive layer is bounded by an end wall and wherein the seal covers the end wall of the touch-sensitive layer.

[0023] The touch-sensitive layer can be designed to detect touches capacitively, inductively, or by means of light barriers.

[0024] In one embodiment, the normals of the end faces point in the same direction within a tolerance range, for example 1%, 2%, or 5%. In other words, the end faces of all layers are arranged one above the other. However, the layers can have different lengths, i.e., different extensions in the direction of the end faces.

[0025] In one embodiment, the seal is bonded to the respective end wall in a material-bonded manner.

[0026] In one embodiment, the seal is formed from a sealing adhesive or from an elastic plastic.

[0027] In one embodiment, the seal is formed as a plug, in particular as a plastic plug.

[0028] In one embodiment, the light-transparent cover is non-reflective within a tolerance range, for example 1%, 2%, 5% or 10% of the reflectivity.

[0029] In one embodiment, the thin-film transistor layer is designed to influence the reflective properties of the reflective ink layer.

[0030] In one embodiment, the light-transparent cover is made of glass or plastic.

[0031] According to a second aspect, the invention relates to a method for manufacturing an electronic paper display comprising a thin-film transistor layer, a reflective ink layer arranged above the thin-film transistor layer and bounded by an end wall, and a light-transparent cover arranged above the ink layer, wherein the light-transparent cover has a flat underside facing the ink layer; comprising: covering the end wall of the thin-film transistor layer and the end wall of the ink layer at least partially by a seal; and bonding the seal to the flat underside of the light-transparent cover in a material-bonded and flat manner.

[0032] The method can be used to manufacture the electronic paper display according to the first aspect. Further process steps arise directly from the characteristics of the electronic paper display according to the first aspect.

[0033] All layers of the electronic paper display can also be laminated.

[0034] Further embodiments are explained with reference to the accompanying drawings. These show: Fig. 1 an electronic paper display according to one embodiment; and Fig. 2 an electronic paper display according to one embodiment.

[0035] Fig. Figure 1 schematically shows an electronic paper display 100, comprising a thin-film transistor layer 101 and a reflective ink layer 103, which is arranged above the thin-film transistor layer 101 and bounded by an end wall 107. The thin-film transistor layer 101 is also bounded by an end wall 107.

[0036] The electronic paper display 100 further comprises a light-transparent cover 109, which is arranged above the ink layer 103, wherein the light-transparent cover 109 has a flat underside 111 which faces the ink layer 103.

[0037] The electronic paper display 100 also has a seal 113 which at least partially covers the end wall 107 of the thin-film transistor layer 101 and the end wall 105 of the ink layer 103 and is bonded to the flat underside 111 of the light-transparent cover 109 in a flat and materially bonded manner.

[0038] As it is in Fig. As indicated in Figure 1, additional layers with different functions may optionally be arranged between the ink layer 103 and the cover 109.

[0039] In one embodiment, the ink layer 103 is arranged directly on the thin-film transistor layer 101. The cover 109 can be arranged directly on the ink layer 103 or on a protective layer (not shown) which can cover the ink layer 103.

[0040] Fig. Figure 2 schematically shows the electronic paper display 100 according to an embodiment with six exemplary layers arranged one above the other.

[0041] A protective layer 115 is arranged on the ink layer 103, protecting the ink layer 103 and bounded by an end wall 117. The seal 113 covers the end wall 117 of the protective layer 115.

[0042] The electronic paper display 100 according to Fig. 2 further comprises an illumination layer 119, which is arranged above the ink layer 103 on the protective layer 115, wherein the illumination layer 119 has a plurality of light sources (not shown), in particular OLEDs, which are configured to illuminate the reflective ink layer 103. The illumination layer 119 is bounded by an end wall 121, wherein the seal 113 completely covers the end wall 119.

[0043] The electronic paper display 100 according to Fig.2 further comprises a touch-sensitive layer 123, which is arranged above the ink layer 103 on the illumination layer 119, wherein the touch-sensitive layer 121 is bounded by an end wall (125) and wherein the seal 113 covers the end wall 125 of the touch-sensitive layer 121. The touch-sensitive layer 121 can be configured to detect touches capacitively or resistively.

[0044] In one embodiment, the seal 113 is bonded to the respective end wall 105, 107, 117, 121, 125. This protects all layers of the electronic paper display 100 against the ingress of moisture.

Claims

[1] Electronic paper display (100), with: a thin-film transistor layer (101) which is bounded by an end wall (107); a reflective ink layer (103) which is arranged above the thin-film transistor layer (101), wherein the ink layer (103) is bounded by an end wall (105); a light-transparent cover (109) which is arranged above the ink layer (103), wherein the light-transparent cover (109) has a flat underside (111) which faces the ink layer (103); and a seal (113) which at least partially covers the end wall (107) of the thin-film transistor layer (101) and the end wall (105) of the ink layer (103) and is bonded to the flat underside (111) of the light-transparent cover (109) in a flat and materially bonded manner. [2] Electronic paper display (100) according to claim 1, wherein the seal (113) partially or completely covers the end wall (107) of the thin-film transistor layer (101). [3] Electronic paper display (100) according to one of the preceding claims, wherein the seal (113) completely covers the end wall (105) of the ink layer (103). [4] Electronic paper display (100) according to one of the preceding claims, wherein the reflective ink layer (103) is arranged on the thin-film transistor layer (101). [5] Electronic paper display (100) according to one of the preceding claims, comprising a protective layer (115) arranged on the reflective ink layer (103), wherein the protective layer (115) has an end wall (117), and wherein the seal (113) covers the end wall (117) of the protective layer (115). [6] Electronic paper display (100) according to claim 5, wherein the protective layer (115) and the thin-film transistor layer (101) are of the same size, in particular of the same length, within a tolerance range. [7] Electronic paper display (100) according to one of the preceding claims, with an illumination layer (119) which is arranged above the ink layer (103), in particular on a protective layer (115), wherein the illumination layer (119) has a plurality of light sources, in particular OLEDs, which are configured to illuminate the reflective ink layer (103), wherein the illumination layer (119) is bounded by an end wall (121), and wherein the seal (113) covers the end wall (121). [8] Electronic paper display (100) according to one of the preceding claims, comprising a touch-sensitive layer (123) which is arranged above the ink layer (103), in particular on a illumination layer (119), wherein the touch-sensitive layer (121) is bounded by an end wall (125) and wherein the seal (113) covers the end wall (125) of the touch-sensitive layer (121). [9] Electronic paper display (100) according to one of the preceding claims, wherein the normals of the end walls (105, 107, 117, 121, 125) point in the same direction within a tolerance range. [10] Electronic paper display (100) according to one of the preceding claims, wherein the seal (113) is bonded to the respective end wall (105, 107, 117, 121, 125). [11] Electronic paper display (100) according to one of the preceding claims, wherein the seal (113) is formed from a sealing adhesive or from an elastic plastic. [12] Electronic paper display (100) according to one of the preceding claims, wherein the seal (113) is formed as a plug, in particular as a plastic plug. [13] Electronic paper display (100) according to one of the preceding claims, wherein the light-transparent cover (109) is non-reflective. [14] Electronic paper display (100) according to one of the preceding claims, wherein the thin-film transistor layer (101) is configured to influence the reflective properties of the reflective ink layer (103). [15] Method for manufacturing an electronic paper display (100) comprising a thin-film transistor layer (101), a reflective ink layer (103) arranged above the thin-film transistor layer (101) and bounded by an end wall (105), and a light-transparent cover (109) arranged above the ink layer (103), wherein the light-transparent cover (109) has a planar underside (111) facing the ink layer (103); comprising: Covering the end wall (107) of the thin-film transistor layer and the end wall (105) of the ink layer (103) at least partially by a seal (113); and joining the seal (113) to the flat underside (111) of the light-transparent cover (109) in a material-coherent and planar manner.

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