DISPLAY DEVICE

According to one embodiment, a display device includes a substrate, a display area displaying an image, a surrounding area surrounding the display area, a display element arranged above the substrate, a first sealing layer formed of an inorganic material and covering the display element, a resin layer arranged on the first sealing layer, a second sealing layer formed of an inorganic material and covering the resin layer, a conductive pad arranged in the surrounding area, and a polarizer arranged above the second sealing layer. At least one of an end portion of the first sealing layer and an end portion of the second sealing layer is located closer to the pad than an end portion of the polarizer is.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2023-142336, filed Sep. 1, 2023, the entire contents of which are incorporated herein by reference.

FIELD

BACKGROUND

Recently, various types of display devices have been proposed. As an example, a display device comprises a polarizer covering a display area and a moisture-proof member in contact with an end portion of the polarizer. The moisture-proof member has a function of preventing moisture from infiltrating a mount area on which a flexible substrate and the like are mounted.

However, contraction of a polarizer due to a

temperature change may form gaps between the polarizer and a moisture-proof member. Moisture may infiltrate mounting area through these gaps.

DETAILED DESCRIPTION

In general, according to one embodiment, a display device comprises a substrate, a display area displaying an image, a surrounding area surrounding the display area, a display element located above the substrate, a first sealing layer formed of an inorganic material and covering the display element, a resin layer arranged on the first sealing layer, a second sealing layer formed of an inorganic material and covering the resin layer, a conductive pad arranged in the surrounding area, and a polarizer arranged above the second sealing layer. At least one of an end portion of the first sealing layer and an end portion of the second sealing layer is located closer to the pad than an end portion of the polarizer is.

The embodiment can provide a display device capable of preventing moisture from infiltrating the mounting area.

Embodiments will be described with reference to the accompanying drawings.

The disclosure is merely an example, and proper changes in keeping with the spirit of the invention, which are easily conceivable by a person of ordinary skill in the art, come within the scope of the invention as a matter of course. In addition, in some cases, in order to make the description clearer, the widths, thicknesses, shapes, etc., of the respective parts are schematically illustrated in the drawings, compared to the actual modes. However, the schematic illustration is merely an example, and adds no restrictions to the interpretation of the invention. In addition, in the specification and drawings, structural elements which function in the same or a similar manner to those described in connection with preceding drawings are denoted by like reference numbers, detailed description thereof being omitted unless necessary.

In the drawings, in order to facilitate understanding, an X-axis, a Y-axis and a Z-axis orthogonal to each other are shown depending on the need. A direction parallel to the X-axis is referred to as a first direction X. A direction parallel to the Y-axis is referred to as a second direction Y. A direction parallel to the Z-axis is referred to as a third direction Z. When various elements are viewed parallel to the third direction Z, the appearance is defined as a plan view.

FIG.1is a plan view showing a schematic configuration example of a display device DSP. The display device DSP shown inFIG.1as an example is a display device including an organic light emitting diode (OLED) as a display element. However, the display device DSP may be a liquid crystal display device including a liquid crystal layer as a display element or a light emitting diode (LED) display device including an LED as a display element.

The display device DSP comprises a substrate10, a plurality of conductive terminals TM, and a flexible substrate5. The substrate10includes a circular body portion10aand an extending portion10bextending from the body portion10ain the second direction Y. The extending portion10bhas a trapezoidal shape whose width in the first direction X decreases as being remote form the body portion10a. The shape of the substrate10in a plan view is not limited to a trapezoidal shape and may be another shape such as a rectangular shape, a square shape, or an elliptic shape. The substrate10is formed of, for example, an insulating material such as glass or plastic.

The display device DSP further comprises a display area DA, which displays an image, and a surrounding area SA, which surrounds the display area DA. The display area DA overlaps with the body portion10ain plan view. In the present embodiment, the display area DA is circular as seen in plan view. The shape of the display area DA in plan view may be another shape such as a rectangular shape, a square shape, or an elliptic shape.

The surrounding area SA includes a mounting area MA. The mounting area MA corresponds to an area overlapping with the extending portion10bin plan view. The plurality of terminals TM are arranged in the mounting area MA (surrounding area SA). In the example inFIG.1, the plurality of terminals TM are arranged at regular intervals in the first direction X. The flexible substrate5is connected to the plurality of terminals TM by an adhesive AD2to be described later. In addition to the flexible substrate5, an IC chip and the like may be further mounted on the mounting area MA.

The display area DA includes a plurality of pixels PX arrayed in a matrix in the first direction X and the second direction Y. Each of the pixels PX comprises a plurality of sub-pixels SP. For example, the pixel PX comprises a red sub-pixel SP1, a green sub-pixel SP2, and a blue sub-pixel SP3. In addition to the sub-pixels of the above three colors, the pixel PX may comprise four or more sub-pixels including a sub-pixel of another color such as white.

The sub-pixel SP comprises a pixel circuit1and a display element20driven by the pixel circuit1. The pixel circuit1comprises a pixel switch2, a drive transistor3, and a capacitor4. The pixel switch2and the drive transistor3are, for example, switching elements consisting of thin-film transistors.

In the pixel switch2, a gate electrode is connected to a scanning line GL. One of the source electrode and drain electrode of the pixel switch2is connected to a signal line SL. The other is connected to the gate electrode of the drive transistor3and the capacitor4. For example, the scanning lines GL extend in the first direction X and the signal lines SL extend in the second direction Y. The signal line SL connects the pixel circuit1with the terminal TM. In the drive transistor3, one of the source electrode and the drain electrode is connected to a power line PL and the capacitor4, and the other is connected to an anode of the display element20. The configuration of the pixel circuit1is not limited to the example shown in the figure.

The display element20is an organic light emitting diode (OLED) in the example inFIG.1. For example, the sub-pixel SP1comprises a display element that emits light corresponding to a red wavelength, the sub-pixel SP2comprises a display element that emits light corresponding to a green wavelength, and the sub-pixel SP3comprises a display element that emits light corresponding to a blue wavelength. The display device DSP further comprises an inner dam ID surrounding the display area DA and an outer dam OD surrounding the display area DA and the inner dam ID. Each of the inner dam ID and the outer dam OD is arranged in the surrounding area SA. The inner dam ID includes an arc portion IDaand a straight portion IDb, which extends in the first direction X. The outer dam OD includes an arc portion ODaand a straight portion ODb, which extends in the first direction X. Centers of the arc portion IDa, the arc portion ODa, the display area DA, and the body portion10aare the same. Centers of the arc portion IDa, the arc portion ODa, the display area DA, and the body portion10amay be different from one another. The straight portion IDband the straight portion ODbare located between the display area DA and the plurality of terminals TM. The number of the dams which the display device DSP comprises is not limited to two: one inner dam ID and one outer dam OD. The number of dams may be one or may be three or more.

The display device DSP further comprises a sealing layer SE1, a sealing layer SE2, a polarizer16, and a moisture-proof member MO1. Dotted areas inFIG.1correspond to the sealing layer SE1and the sealing layer SE2. Each of the sealing layer SE1and the sealing layer SE2overlaps with the inner dam ID and the outer dam OD in plan view.

The sealing layer SE1includes a circular body portion S1aand an extending portion S1bextending from the body portion S1ain the second direction Y. The sealing layer SE2includes a circular body portion S2aand an extending portion S2bextending from the body portion S2ain the second direction Y. The body portion S1a, the body portion S2a, and the polarizer16entirely overlap with an area surrounded by the outer dam OD in plan view. The body portion S1a, the body portion S2a, and the polarizer16may be larger than or smaller than the area surrounded by the outer dam OD in plan view. The sizes of the body portion S1a, the body portion S2a, and the polarizer16may be different from one another.

Each of the boundary between the body portion S1aand the extending portion S1band the boundary between the body portion S2aand the extending portion S2bmay overlap with the straight portion ODbof the outer dam OD in plan view. In the example shown inFIG.1, the extending portion S1band the extending portion S2bare formed in a rectangular shape having long sides overlapping with the straight portion ODbin plan view. In addition, in the example shown inFIG.1, the extending portion S1band the extending portion S2bdo not overlap with the flexible substrate5in plan view.

In the example inFIG.1, the moisture-proof member MO1is formed in a rectangular shape having long sides overlapping with the straight portion ODbin plan view. The moisture-proof member MO1overlaps with the extending portion S1b, the extending portion S2b, and the flexible substrate5in plan view.

FIG.2is a schematic cross-sectional view of the display device DSP in the display area DA. The display device DSP further comprises a circuit layer13, an insulating layer14, a rib15, a resin layer RS1, a resin layer RS2, and an adhesive AD1. The display element20includes a pixel electrode PE, an organic layer OR, and a common electrode CE.

The circuit layer13is provided on the substrate10described above. The circuit layer13includes various circuits such as the pixel circuit1shown inFIG.1and various lines such as the scanning line GL, the signal line SL, and the power line PL. As described in detail later, the circuit layer13includes an insulating layer11and an insulating layer12(refer toFIG.3). The circuit layer13is covered with the insulating layer14. The insulating layer14has a function of flattening irregularities formed by the circuit layer13. The insulating layer14is formed of an organic material. The display element20is arranged above the substrate10.

Each of the plurality of pixel electrodes PE is arranged on the insulating layer14. Though not shown inFIG.2, the pixel electrode PE is electrically connected with the pixel electrode1shown inFIG.1through a contact hole penetrating the insulating layer14.

The end portions of the pixel electrode PE

are covered with the rib15. The rib15is formed in a grating shape surrounding the plurality of sub-pixels SP in plan view. The rib15is formed of, for example, an organic material.

The organic layer OR is arranged on the pixel electrode PE. The common electrode CE is arranged on the organic layer OR and the rib15. For example, the common electrode CE is formed to spread across the sub-pixels SP.

The pixel electrode PE may be formed of a transparent conductive material such as an indium tin oxide (ITO) or an indium zinc oxide (IZO) or may be a stacked layer body of the transparent conductive material and a metal material. The common electrode CE is formed of a metal material such as magnesium and silver. Further, the common electrode CE may be formed of a transparent conductive material such as ITO or IZO. For example, the pixel electrode PE correspond to the anode of the display element20, and the common electrode CE corresponds to a cathode of the display element20.

The organic layer OR emits light according to an electric current flowing between the pixel electrode PE and the common electrode CE. For example, the organic layer OR comprises a multilayer structure consisting of a hole injection layer, a hole transport layer, an electron blocking layer, a light emitting layer, a hole blocking layer, an electron transport layer, and an electron injection layer. The organic layer OR may comprise a tandem structure including a plurality of light emitting layers.

The sealing layer SE1covers the display element20. More specifically, the sealing layer SE1covers the common electrode CE. The resin layer RS1is arranged on the sealing layer SE1. The sealing layer SE2covers the resin layer RS1. The resin layer RS2is arranged on the sealing layer SE2. The polarizer16is arranged above the sealing layer SE2. More specifically, the polarizer16is bonded to the resin layer RS2by the adhesive AD1.

The sealing layer SE1and the sealing layer SE2are formed of, for example, inorganic material such as silicon nitride (SiNx), silicon oxide (Siox), and silicon oxynitride (SiON). The resin layer RS1and the resin layer RS2are formed of, for example, a resinous material (organic insulating material) such as acrylic resin. The adhesive AD1is formed of, for example, optical clear adhesive (OCA) or the like.

FIG.3is a schematic cross-sectional view of the display device DSP along line A-A line inFIG.1. The circuit layer13includes the insulating layer11, the insulating layer12, and the signal line SL. The insulating layer11covers the substrate10. The signal line SL is arranged on the first insulating layer11. The insulating layer12covers the signal line SL. Each of the insulating layer11and the insulating layer12is formed of, for example, an inorganic material such as silicon nitride or silicon oxide.

The display device DSP further comprises the inner dam ID, the outer dam OD, the moisture-proof member MO1, a conductive layer CL, an insulating layer17, and a moisture-proof member MO2.

The inner dam ID and the outer dam OD are arranged on the insulating layer12. The inner dam ID includes a protrusion ID1and a protrusion ID2. The protrusion ID2covers the protrusion ID1. The outer dam OD includes the protrusion OD1and the protrusion OD2. The protrusion OD2covers the protrusion OD1. The protrusion OD1includes a part of the insulating layer17. The inner dam ID has a function of damming up the resin layer RS1. The outer dam OD has a function of damming up the resin layer RS2.

InFIG.3, an end portion16E of the polarizer16is located directly above the outer dam OD. In other words, the outer dam OD overlaps with the end portion16E of the polarizer16in plan view. The outer dam OD may not overlap with the end portion16E in plan view.

The conductive layer CL is arranged on the insulating layer12in the mounting area MA. The conductive layer CL is electrically connected to the signal line SL through a contact hole CH penetrating the insulating layer12.

The insulating layer17is arranged in the surrounding area SA. The insulating layer17covers the conductive layer CL. The protrusion ID1, the protrusion OD1, and the insulating layer17are formed, for example, of the same organic material as the insulating layer14shown inFIG.2and in the same manufacturing process as the insulating layer14shown inFIG.2. The protrusion ID2and the protrusion OD2are formed, for example, of the same organic material as the rib15shown inFIG.2and in the same manufacturing process as the rib15shown inFIG.2.

The insulating layer17overlaps with an aperture OP overlapping with the terminal TM. The flexible substrate5is bonded to the conductive layer CL through the aperture OP by the adhesive AD2. In the example inFIG.3, the adhesive AD2covers a part of the insulating layer12and a part of the insulating layer17. For example, a conductive member such as an anisotropic conductive film may be used as the adhesive AD2.

Each of the sealing layer SE1and the sealing layer SE2covers the inner dam ID (straight portion IDb) and the outer dam OD (straight portion ODb). In the example inFIG.3, the end portion of the resin layer RS1is located in the vicinity of the inner dam ID. In addition, the end portion of the resin layer RS2is located in the vicinity of the outer dam OD. The sealing layer SE1is provided on the resin layer17. In an area closer to the terminal TM than the end portion of the resin layer RS1is, an upper surface S1U of the sealing layer SE1is in contact with the sealing layer SE2.

An end portion S1E of the sealing layer SE1and an end portion S2E of the sealing layer SE2are closer to the terminal TM than the end portion16E of the polarizer16is. More specifically, each of the end portion S1E and the end portion S2E is located between the end portion16E and the aperture OP. In the example inFIG.3, the end portion S1E and the end portion S2E are not in contact with the adhesive AD2. The end portion S1E and the end portion S2E are arranged on the insulating layer17. InFIG.3, the end portion S1E overlaps with the end portion S2E. The end portion S1E may not overlap with the end portion S2E.

The moisture-proof member MO1is arranged above the insulating layer17and is in contact with the end portion16E of the polarizer16. The moisture-proof member MO1overlaps with the end portion S1E of the sealing layer SE1and the end portion S2E of the sealing layer SE2. InFIG.3, the moisture-proof member MO1covers the end portion S1E, the end portion S2E, and an end portion5E of the flexible substrate5. In the example inFIG.3, the moisture-proof member MO1is in contact with an upper surface S2U of the sealing layer SE2. In the mounting area MA, the sealing layer SE1and the sealing layer SE2are located between the insulating layer17and the moisture-proof member MO1. That is, each of a part of the sealing layer SE1and a part of the sealing layer SE2is arranged between the insulating layer17and the moisture-proof member MO1. InFIG.3, a moisture-proof member MO2is in contact with the substrate10, the insulating layer11, the adhesive AD2, and the flexible substrate5.

The moisture-proof member MO1and the moisture-proof member MO2are formed of, for example, resin material such as an epoxy resin and an acrylic resin. The moisture-proof member MO1has a function of preventing moisture from infiltrating the mount area MA, for example, between the end portion16E of the polarizer16and the end portion5E of the flexible substrate5. The moisture-proof member MO2has a function of preventing moisture from infiltrating the mounting area MA from the end portion of the substrate10.

FIG.4is a schematic plan view showing the terminal TM in enlarged manner. Next, effects exhibited by the display device DSP according to the present embodiment will be described with reference toFIG.3andFIG.4. An issue that may occur in a case where the end portion SIE of the sealing layer SE1and the end portion S2E of the sealing layer SE2are located closer to the display area DA shown inFIG.1than the end portion16E of the polarizer16is will be described below. A contraction of the polarizer16due to a temperature change may form gaps between the end portion16E and the moisture-proof member MO1. The outer dam OD located directly under the end portion16E is not covered with the sealing layer SE1and the sealing layer SE2. Thus, a moisture that has infiltrated the gaps reaches the protrusion OD2through an end portion ALE of the adhesive AD1. The protrusion OD2and the insulating layer17are formed of organic materials and thus are easily penetrated by moisture. Therefore, the moisture that has reached the protrusion OD2penetrates into the terminal TM through the insulating layer17. When moisture penetrates into an area AR shown inFIG.4(an area between adjacent terminals TM), electricity flows between the adjacent terminals TM via moisture. As a result, the terminals TM may be corrode due to a potential difference between the terminal TM (conductive layer CL) and moisture and may become easily detachable.

In the present embodiment, the end portion S1E of the sealing layer SE1and the end portion S2E of the sealing layer SE2are closer to the terminal TM than the end portion16E of the polarizer16is. Therefore, inFIG.3, moisture that has infiltrated from gaps between the end portion16E and the moisture-proof member MO1will move along the end portion ALE of the adhesive AD1and reach the sealing layer SE2covering the outer dam OD. The sealing layer SE1and the sealing layer SE2are formed of inorganic material and thus are not easily penetrated by moisture. Therefore, the infiltration of moisture to the mounting area MA can be suppressed.

In addition, the infiltration of moisture to the mounting area MA can be further suppressed by stacking the sealing layer SE1and the sealing layer SE2, which are not easily penetrated by moisture. The sealing layers may be stacked layer of three or more layers. As described in detail below, the sealing layer may be a single-layer having the sealing layer SE1or the sealing layer SE2.

The display device DSP comprises the moisture-proof member MO1and the moisture-proof member MO2. The infiltration of moisture to the mounting area MA can be further suppressed. Further, the infiltration of moisture between the end portion5E and the end portion S1E and the end portion S2E can be suppressed by the moisture-proof member MO1covering the end portion5E of the flexible substrate5.

Next, another configuration example of the display device DSP will be described. In each example, the same or similar elements as those of the display device DSP described above are referred to by the same reference numbers and explanations of these elements are omitted.

FIG.5is a cross-sectional view showing another configuration example of the display device DSP. In the example shown inFIG.5, the end portion S1E of the sealing layer SE1is closer to the terminal TM than the end portion16E of the polarizer16is, and the end portion S2E of the sealing layer SE2is closer to the inner dam ID than the end portion16E of the polarizer16is. In other words, the sealing layer SE1is located directly below the end portion16E, but the sealing layer SE2is not located directly below the end portion16E. The moisture-proof member MO1is in contact with the upper surface SIU of the sealing layer SE1in the mounting area MA.

In the display device DSP having this configuration as well, the sealing layer SE1can prevent moisture from infiltrating the mounting area MA. The display device DSP ofFIG.5can achieve advantages similar to the above advantages.

FIG.6is a cross-sectional view showing yet another configuration example of the display device DSP. In the example shown inFIG.6, the end portion S2E of the sealing layer SE2is closer to the terminal TM than the end portion16E of the polarizer16is, and the end portion S1E of the sealing layer SE1is closer to the inner dam ID than the end portion16E of the polarizer16is. In other words, the sealing layer SE2is located directly below the end portion16E, but the sealing layer SE1is not located directly below the end portion16E.

In the display device DSP having this configuration as well, the sealing layer SE2can prevent moisture from infiltrating the mounting area MA. The display device DSP ofFIG.6can achieve advantages similar to the above advantages.

In the above example, for example, the sealing layer SE1corresponds to a first sealing layer, the sealing layer SE2corresponds to a second sealing layer, and the outer dam OD corresponds to a protrusion.

All of the display devices that can be implemented by a person of ordinary skill in the art through arbitrary design changes to the display device described above as the embodiment of the present invention come within the scope of the present invention as long as they are in keeping with the spirit of the present invention.

Various types of the modified examples are easily conceivable within the category of the ideas of the present invention by a person of ordinary skill in the art and the modified examples are also considered to fall within the scope of the present invention. For example, additions, deletions or changes in design of the constituent elements or additions, omissions, or changes in condition of the processes arbitrarily conducted by a person of ordinary skill in the art, in the above embodiments, fall within the scope of the present invention as long as they are in keeping with the spirit of the present invention.

In addition, the other advantages of the aspects described in the embodiments, which are obvious from the descriptions of the present specification or which can be arbitrarily conceived by a person of ordinary skill in the art, are considered to be achievable by the present invention as a matter of course.