Patent Application
20200411779
The present invention relates to a display device.
In recent years, in the field of display devices that include a flexible display panel and housing, there has been active development of technology for fixing a flexible display to a housing of a display device used in a smart phone, television, or the like, with a region of a display region of the flexible display panel flat and unbent and another region of the display region bent (curved), for example, only ends of the display region of the flexible display panel being bent.
PTL 1: JP 2007-86771A (published on Apr. 5, 2007).
However, when the flexible display panel is fixed to the housing of the display device with one region of the display region flat and unbent and another region bent, the bending portion of the display region is under constant stress due to the bending. Thus, an active element (for example, a thin film transistor element (TFT element)) and/or a display element (for example, an organic EL element) provided at the bending portion of the display region of the flexible display panel may crack or break.
PTL 1 describes a configuration in which a stress relief layer is provided throughout a display region of a flexible display panel. The stress relief layer is provided near a specific layer, i.e., a conductive layer that is very brittle with respect to bending and with an easily breakable film to mitigate stress applied to the conductive layer. This allows cracking and the like in the specific layer to be suppressed.
However, the active element and display element provided at the bending portion of the display region of the flexible display panel is constituted by a plurality of layered films. Thus, the configuration described in PTL 1, in which the stress relief layer is provided to mitigate the stress applied to the specific layer, does not sufficiently produce an effect of suppressing breakage of the active elements and display elements provided at the bending portion of the display region of the flexible display panel due to there being constant stress caused by the bending of the display region of the flexible display panel.
To solve the problems described above, a display device according to the present invention includes:
a flexible display panel including a lower face film and a layered film, the layered film being formed above the lower face film and including a resin layer, a moisture-proof layer, a TFT layer, a display element layer, and a sealing layer; and
a housing,
wherein the housing includes a curved face region with curvature and a planar face region,
a stress adjustment layer is provided in the layered film in a first region of the flexible display panel, the first region overlapping the curved face region, or in the layered film in a second region of the flexible display panel, the second region overlapping the planar face region, and
when curvature of the flexible display panel is zero, an absolute value of film stress of a first layered film is greater than an absolute value of film stress of a second layered film, the first layered film being all layered film that is formed above the lower face film and includes the layered film in the first region, and the second layered film being all layered film that is formed above the lower face film and includes the layered film in the second region.
According to the above-described configuration, a display device can be provided that is capable of preventing breaking of a plurality of transistor elements in the TFT layer and a plurality of display elements in the display element layer provided in the first region, which is a bending region, when the flexible display panel is bent in a specific direction in the first region, which is a bending region.
According to an aspect of the present invention, a display device can be provided that is capable of preventing breaking of a plurality of transistor elements in the TFT layer and a plurality of display elements in the display element layer provided in the first region, which is a bending region, when the flexible display panel is bent in a specific direction in the first region, which is a bending region.
A description follows regarding embodiments of the present invention, with reference to
Note that, in the following embodiments, description is made of an organic electro luminescence (EL) element as an example of a display element (optical element). However, the embodiment is not limited thereto, and may be, for example, a reflective-type liquid crystal display element, in which luminance and transmittance are controlled by a voltage and background light is not required.
The display element (optical element) is an optical element whose luminance and transmittance are controlled by an electric current, and examples of the electric current-controlled optical element include an organic electro luminescence (EL) display provided with an organic light emitting diode (OLED), an EL display such as an inorganic EL display provided with an inorganic light emitting diode, or a quantum dot light emitting diode (QLED) display provided with a QLED.
In the following, a flexible organic EL display panel 2 of a comparative example and a flexible organic EL display panel 2a of the first embodiment of the present invention will be described with reference to
In the following, a “same layer” refers to a layer formed in the same process using the same material, a “lower layer” refers to a layer formed in a process before the layer being compared, and an “upper layer” refers to a layer formed in a process after the layer being compared.
A process of manufacturing the flexible organic EL display panel 2 will be described with reference to
First, a resin layer 12 is formed above a transparent support substrate (for example, a mother glass substrate) that is removed and replaced with a lower face film 10 in a later process (step S1). Next, a barrier layer 3 is formed (step S2). Next, a TFT layer 4 is formed (step S3). Next, an organic EL element layer 5, i.e., a light-emitting element layer, is formed as a display element (step S4). Next, a sealing layer 6 is formed (step S5). Next, a lower face of the resin layer 12 is irradiated with laser light through the support substrate to reduce a bonding force between the support substrate and the resin layer 12, and the support substrate is peeled from the resin layer 12 (step S6). This step is also referred to as a Laser Lift Off process (LLO process). Next, the lower face film 10 is bonded to the face of the resin layer 12 from which the support substrate was peeled off with an adhesion layer therebetween (step S7). Next, a layered body including the lower face film 10, the resin layer 12, the barrier layer 3, the TFT layer 4, the organic EL element layer 5, and the sealing layer 6 is divided and a plurality of individual pieces are obtained (step S8). Next, an electronic circuit board (for example, an IC chip) is crimped and mounted on a terminal TM of an edge portion using an Anisotropic Conductive Film (ACF) (step S9).
Examples of the material of the lower face film 10 include polyethylene terephthalate (PET), but are not limited thereto.
Examples of the material of the resin layer 12 include a polyimide resin, an epoxy resin, and a polyamide resin, but are not limited thereto.
The barrier layer 3 is a layer that inhibits moisture or impurities from reaching the TFT layer 4 and the organic EL element layer 5 when a flexible organic EL display panel 2 is being used, and may be constituted, for example, by a silicon oxide film, a silicon nitride film, or a silicon oxynitride film, or by a layered film of these films, formed using chemical vapor deposition (CVD).
The TFT layer 4 is provided on a layer above the resin layer 12 and the barrier layer 3. The TFT layer 4 includes a semiconductor film 15, an inorganic insulating film 16 (a gate insulating film) as an upper layer of the semiconductor film 15, a gate electrode GE as an upper layer of the inorganic insulating film 16, an inorganic insulating film 18 as an upper layer of the gate electrode GE, capacity wiring CE as an upper layer of the inorganic insulating film 18, an inorganic insulating film 20 as an upper layer of the capacity wiring CE, a source-drain wiring line SH including a source-drain electrode as an upper layer of the inorganic insulating film 20, and a flattening film 21 as an upper layer of the source-drain wiring line SH.
In other words, the layer that forms a thin film transistor Tr (TFT) as an active element includes the semiconductor film 15, the inorganic insulating film 16 (gate insulating film), the gate electrode GE, the inorganic insulating film 18, the inorganic insulating film 20, the source-drain wiring line SH, and the flattening film 21.
The semiconductor film 15 is formed of low-temperature polysilicon (LTPS) or an oxide semiconductor, for example. Note that, although the TFT provided with the semiconductor film 15 as the channel is illustrated as having a top gate structure in
Each of the gate electrodes GE, the capacitance electrodes CE, the source-drain wiring line SH, the terminal wiring lines TW, and the terminals TM is formed of, for example, a monolayer film or a layered film of metal containing at least one of aluminum (Al), tungsten (W), molybdenum (Mo), tantalum (Ta), chromium (Cr), titanium (Ti), and copper (Cu).
The inorganic insulating films 16, 18, 20 may be formed, for example, by CVD, of a silicon oxide (SiOx) film, a silicon nitride (SiNx) film, or a silicon oxynitride film, or by a layered film of these.
The flattening film (interlayer insulating film) 21 may be formed, for example, of a coatable photosensitive organic material, such as a polyimide resin and an acrylic resin.
The organic EL element layer 5 is provided with an anode 22 in an upper layer overlying the flattening film 21, a bank 23 that covers an edge of the anode 22, an electroluminescence (EL) layer 24 in an upper layer overlying the anode 22, and a cathode 25 in an upper layer overlying the EL layer 24. A light-emitting element and includes the anode 22 having an island shape, the EL layer 24, and the cathode 25 on a per subpixel SP basis. The bank 23 (anode edge cover) 23 can be formed of a coatable photosensitive organic material, such as a polyimide resin or an acrylic resin, for example. The organic EL element layer 5 forms a display region and is provided on a layer above the TFT layer 4.
For example, the EL layers 24 are formed by layering a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, and an electron injection layer in this order, from the lower layer side. The light-emitting layer is formed in an island shape for each subpixel by a vapor deposition method or ink-jet method, but the other layers may be a solid-like common layer. A configuration is also possible in which one or more layers are not formed, out of the hole injection layer, the hole transport layer, the electron transport layer, and the electron injection layer.
The anode (anode electrode) 22 is photoreflective and is formed by layering Indium Tin Oxide (ITO) and an alloy containing Ag, for example. The cathode 25 may be formed of a transparent conductive material such as Indium Tin Oxide (ITO) or Indium Zinc Oxide (IZO).
Holes and electrons are recombined in the EL layer 24 by a driving current between the anode 22 and the cathode 25 in the organic EL element layer 5, and the excitons generated thereby fall to the ground state such that light is emitted. Since the cathode 25 is transparent and the anode 22 has light reflectivity, the light emitted from the EL layer 24 travels upward and becomes top-emitting.
The sealing layer 6 is transparent, and includes a first inorganic sealing film 26 that covers the cathode 25, an organic sealing film 27 that is formed on the first inorganic sealing film 26, and a second inorganic sealing film 28 that covers the organic sealing film 27. The sealing layer 6 covering the organic EL element layer 5 inhibits foreign matter, such as water and oxygen, from penetrating to the organic EL element layer 5.
Each of the first inorganic sealing film 26 and the second inorganic sealing film 28 may be formed of, for example, a silicon oxide film, a silicon nitride film, or a silicon oxynitride film, or of a layered film of these, formed through CVD. The organic sealing film 27 is thicker than the first inorganic sealing film 26 and the second inorganic sealing film 28, is a transparent organic film, and can be formed of a coatable photosensitive organic material such as a polyimide resin or an acrylic resin.
In the example given above, the flexible organic EL display panel 2 of the comparative example is manufactured by a manufacturing process including a LLO process, but the embodiment is not limited thereto. For example, in an example in which a flexible substrate with high heat resistance capable of withstanding the heat of the process from step S1 to step S5 described above is used as a support substrate, the substrate does not need to be replaced. Thus, step S6 and step S7 described above can be omitted.
(a) of
In the flexible organic EL display panel 2 illustrated in (a) of
As illustrated in (a) of
Note that the position of the neutral plane CM in the thickness of the lower face film 10 is slightly above the immediate region. This is because in the case of the flexible organic EL display panel 2, the lower face film 10 have a structure with sufficiently high rigidity with respect to the layered film 11.
As illustrated in (c) of
Thus, the transistor element (Tr) and the organic EL element provided in the layered film 11 in the first regions R1, R2 of the flexible organic EL display panel 2 may break due to the tensile stress described above.
As illustrated in (c) of
(b) of
As illustrated in (b) of
As illustrated in (d) of
Thus, the transistor element (Tr) and the organic EL element provided in the layered film 11 in the first regions R1, R2 of the flexible organic EL display panel 2 may break due to the compressive stress described above.
As illustrated in (d) of
Hereinafter, a display device of the present embodiment including a flexible organic EL display panel and a housing will be described. The display device of the present embodiment is capable of suppressing breakage of a transistor element (Tr) and/or an organic EL element provided in the first regions R1, R2 when the first regions R1, R2, which are bending regions, are bent outward.
(a) of
As illustrated in (a) of
Specifically, as will be described later, in the present embodiment, the second layered film 11a is formed with the film stress of the second layered film 11a, from the lower face film 10, formed in the second region R3 of the flexible organic EL display panel 2a being approximately zero, i.e., there being essentially no film stress.
On the other hand, the film stress of the first layered film 31, from the lower face film 10, formed in the first regions R1, R2 of the flexible organic EL display panel 2a is compressive stress. In other words, the first layered film 31 is formed with the film stress of the first layered film 31, from the lower face film 10, formed in the first regions R1, R2 being compressive stress in a state before the first regions R1, R2 of the flexible organic EL display panel 2a are bent.
As illustrated in the drawings, the compressive stress of the first layered film 31, from the lower face film 10, in a state before the first regions R1, R2 are bent and the tensile stress of the first layered film 31, from the lower face film 10, caused by outward bending of the first regions R1, R2 counteract one another.
Accordingly, the first layered film 31 is preferably formed with the amount of the tensile stress of the first layered film 31, from the lower face film 10, caused by outward bending of the first regions R1, R2 and the amount of compressive stress of the first layered film 31, from the lower face film 10, in a state before the first regions R1, R2 are bent being approximately equal.
Thus, in the flexible organic EL display panel 2a, the transistor element (Tr) and/or the organic EL element provided in the first regions R1, R2 can be prevented from breaking when the first regions R1, R2 are bent.
In the display device 60a illustrated in (a) of
Note that the housing 40, 40′ is bent outward and includes the curved face regions having a curvature and a planar face region.
In the case the flexible organic EL display panel 2a illustrated in (a) of
The first layered film 31 formed in the first regions R1, R2 includes the resin layer 12, a first moisture-proof layer 3a where film stress from the lower face film 10 corresponds to compressive stress, a second moisture-proof layer 3b where film stress from the lower face film 10 corresponds to tensile stress, a first stress adjustment layer 32 formed above the second moisture-proof layer 3b where the film stress of the first layered film 31, from the lower face film 10, corresponds to compressive stress, the TFT layer 4, the organic EL element layer 5, and the sealing layer 6.
Note that in a case in which the first stress adjustment layer 32 is formed only the first regions R1, R2, the first stress adjustment layer 32 is leveled by the flattening film 21, which is the top layer of the TFT layer 4. Thus, the organic EL element layer 5 and the sealing layer 6 are formed at the same position in terms of height in the first regions R1, R2 and the second region R3.
The first moisture-proof layer 3a and the second moisture-proof layer 3b are formed with the amount of compressive stress of the first moisture-proof layer 3a, from the lower face film 10, provided in the flexible organic EL display panel 2a illustrated in (a) of
In the present embodiment, the first moisture-proof layer 3a is formed of silicon oxide (SiOx), and the second moisture-proof layer 3b is formed of silicon oxynitride (SiNxOy), but no such limitation is intended. Stress can be controlled by adjusting CVD deposition conditions, film thickness, and the like of the first moisture-proof layer 3a and the second moisture-proof layer 3b.
Note that the first stress adjustment layer 32 can be formed using, for example, silicon nitride (SiNx), silicon oxide (SiOx), polyimide resin, or the like and so that the film stress of the first layered film 31 from the lower face film 10 corresponds to compressive stress.
To make the amount of tensile stress of the first layered film 31, from the lower face film 10 when the first regions R1, R2 are bend outward, that includes the first stress adjustment layer 32 and the amount of compressive stress of the first layered film 31, from the lower face film 10 in state before the first regions R1, R2 are bent (the curvature of the flexible organic EL display panel 2a is zero), that includes the first stress adjustment layer 32 approximately equal, the CVD deposition conditions and the film thickness can be adjusted in the case of the first stress adjustment layer 32 being formed of silicon nitride (SiNx) or silicon oxide (SiOx), and the material, film thickness, and cure conditions can be adjusted in the case of the first stress adjustment layer 32 being formed of a polyimide resin.
According to the flexible organic EL display panel 2a illustrated in (a) of
In the case the flexible organic EL display panel 2a illustrated in (b) of
The second layered film 11a formed in the second region R3 includes the resin layer 12, the first moisture-proof layer 3a where film stress from the lower face film 10 corresponds to compressive stress, the second moisture-proof layer 3b where film stress from the lower face film 10 corresponds to tensile stress, the TFT layer 4, the organic EL element layer 5, and the sealing layer 6. The second moisture-proof layer 3b is a stress adjustment layer formed above the first moisture-proof layer 3a with the absolute value of the compressive stress of the first layered film 31 being greater than the absolute value of the film stress of the second layered film 11a.
Note that in a case in which the second moisture-proof layer 3b is formed only in the second region R3, the first stress adjustment layer 32 is leveled by the flattening film 21, which is the top layer of the TFT layer 4. Thus, the organic EL element layer 5 and the sealing layer 6 are formed at the same position in terms of height in the first regions R1, R2 and the second region R3.
The first moisture-proof layer 3a and the second moisture-proof layer 3b are formed with the amount of compressive stress of the first moisture-proof layer 3a, from the lower face film 10, provided in the flexible organic EL display panel 2a illustrated in (b) of
To make the amount of tensile stress of the first layered film 31, from the lower face film 10 when the first regions R1, R2 are bend outward, that includes the first moisture-proof layer 3a and the amount of compressive stress of the first layered film 31, from the lower face film 10 in state before the first regions R1, R2 are bent (the curvature of the flexible organic EL display panel 2a is zero), that includes the first moisture-proof layer 3a approximately equal, the CVD deposition conditions and film thickness of the first moisture-proof layer 3a can be adjusted.
According to the flexible organic EL display panel 2a illustrated in (b) of
The flexible organic EL display panel 2a illustrated in (a) of
The two first regions R1, R2 are located between the one second region R3 and are regions located at or near either end of the display region DA in the left-right direction of the drawing.
According to the flexible organic EL display panel 2a illustrated in (a) of
The flexible organic EL display panel 2b illustrated in (b) of
The two first regions R4, R5 are located between the one second region R3 and are regions located at or near either end of the display region DA in the up-down direction of the drawing.
According to the flexible organic EL display panel 2b illustrated in (b) of
The flexible organic EL display panel 2c illustrated in (c) of
The one first region R6 is located around the one second region R3 and is a region located at or near the edge of the display region DA.
According to the flexible organic EL display panel 2c illustrated in (c) of
As illustrated in (a) of
The flexible organic EL display panel 2a illustrated in (a) of
As illustrated in (b) of
The flexible organic EL display panel 2a illustrated in (b) of
In addition, because the changes in the properties of the transistor elements (Tr) from the first regions R1, R2 to the second region R3 are subtle, display unevenness at the boundary portion between the first regions R1, R2 and the second region R3 can be suppressed.
(a) of
As illustrated in (a) of
The second layered film 11 is the same as the layered film 11 illustrated in
The second layered film 11 is formed with the film stress of the second layered film 11, from the lower face film 10, formed in the second region R3 of the flexible organic EL display panel 2a illustrated in (a) of
On the other hand, the film stress of the first layered film 31, from the lower face film 10, formed in the first regions R1, R2 of the flexible organic EL display panel 2a is compressive stress. In other words, the first layered film 31 is formed with the film stress of the first layered film 31, from the lower face film 10, formed in the first regions R1, R2 being compressive stress in a state before the first regions R1, R2 of the flexible organic EL display panel 2a are bent (when the curvature of the flexible organic EL display panel 2a is zero).
As illustrated in the drawings, the compressive stress of the first layered film 31, from the lower face film 10, in a state before the first regions R1, R2 are bent and the tensile stress of the first layered film 31, from the lower face film 10, caused by outward bending of the first regions R1, R2 counteract one another.
Accordingly, the first layered film 31 is preferably formed with the amount of the tensile stress of the first layered film 31, from the lower face film 10, caused by outward bending of the first regions R1, R2 and the amount of compressive stress of the first layered film 31, from the lower face film 10, in a state before the first regions R1, R2 are bent being approximately equal.
Thus, in the flexible organic EL display panel 2a, the transistor element (Tr) and/or the organic EL element provided in the first regions R1, R2 can be prevented from breaking when the first regions R1, R2 are bent outward in the case of the flexible organic EL display panel 2a being fixed to the housing 40 of a display device.
In the display device 60a illustrated in (a) of
In the case the flexible organic EL display panel 2a illustrated in (a) of
The TFT layer 4a is different from the TFT layer 4 of the second layered film 11 formed in the second region R3 in that the TFT layer 4a includes a second stress adjustment layer 21a. In other words, in the case of the TFT layer 4a, the flattened layer includes the second stress adjustment layer 21a and the flattening film 21.
The second stress adjustment layer 21a can be formed similarly to the first stress adjustment layer 32 illustrated in (a) of
To make the amount of tensile stress of the first layered film 31, from the lower face film 10 when the first regions R1, R2 are bend outward, that includes the second stress adjustment layer 21a and the amount of compressive stress of the first layered film 31, from the lower face film 10 in state before the first regions R1, R2 are bent, that includes the second stress adjustment layer 21a approximately equal, the CVD deposition conditions and the film thickness can be adjusted in the case of the second stress adjustment layer 21a being formed of silicon nitride (SiNx) or silicon oxide (SiOx), and the material, film thickness, and cure conditions can be adjusted in the case of the second stress adjustment layer 21a being formed of a polyimide resin.
According to the flexible organic EL display panel 2a illustrated in (a) of
In the case of the flexible organic EL display panel 2a illustrated in (b) of
The sealing layer 6a is different from the sealing layer 6 of the second layered film 11 formed in the second region R3 in that the sealing layer 6a includes a third stress adjustment layer 27a. In other words, in the sealing layer 6a, the third stress adjustment layer 27a is formed between the first inorganic sealing film 26 and the organic sealing film 27.
The third stress adjustment layer 27a can be formed similarly to second stress adjustment layer 21a illustrated in (a) of
To make the amount of tensile stress of the first layered film 31, from the lower face film 10 when the first regions R1, R2 are bend outward, that includes the third stress adjustment layer 27a and the amount of compressive stress of the first layered film 31, from the lower face film 10 in state before the first regions R1, R2 are bent, that includes the third stress adjustment layer 27a approximately equal, the CVD deposition conditions and the film thickness can be adjusted in the case of the third stress adjustment layer 27a being formed of silicon nitride (SiNx) or silicon oxide (SiOx), and the material, film thickness, and cure conditions can be adjusted in the case of the third stress adjustment layer 27a being formed of a polyimide resin.
According to the flexible organic EL display panel 2a illustrated in (b) of
Next, the second embodiment according to the present invention will be described with reference to
(a) of
As illustrated in (a) of
In the present embodiment, the second layered film 11a is formed with the film stress of the second layered film 11a, from the lower face film 10, formed in the second region R3 of the flexible organic EL display panel 2d being approximately zero, i.e., there being essentially no film stress.
On the other hand, the film stress of the first layered film 33, from the lower face film 10, formed in the first regions R1, R2 of the flexible organic EL display panel 2d is tensile stress. In other words, the first layered film 33 is formed with the film stress of the first layered film 33, from the lower face film 10, formed in the first regions R1, R2 being tensile stress in a state before the first regions R1, R2 of the flexible organic EL display panel 2d are bent (when the curvature of the flexible organic EL display panel 2d is zero).
As illustrated in the drawings, the tensile stress of the first layered film 33, from the lower face film 10, in a state before the first regions R1, R2 are bent and the compressive stress of the first layered film 33, from the lower face film 10, caused by inward bending of the first regions R1, R2 counteract one another.
Accordingly, the first layered film 33 is preferably formed with the amount of the compressive stress of the first layered film 33, from the lower face film 10, caused by inward bending of the first regions R1, R2 and the amount of tensile stress of the first layered film 33, from the lower face film 10, in a state before the first regions R1, R2 are bent being approximately equal.
Thus, in the flexible organic EL display panel 2d, the transistor element (Tr) and/or the organic EL element provided in the first regions R1, R2 can be prevented from breaking when the first regions R1, R2 are bent inward in the case of the flexible organic EL display panel 2d being fixed to the housing 50 of the display device 70a.
In the display device 70a illustrated in (a) of
Note that the housing 50, 50′ is bent inward and includes the curved face regions having a curvature and a planar face region.
In the case the flexible organic EL display panel 2d illustrated in (a) of
The first layered film 33 formed in the first regions R1, R2 includes the resin layer 12, a first moisture-proof layer 3a where film stress from the lower face film 10 corresponds to compressive stress, a second moisture-proof layer 3b where film stress from the lower face film 10 corresponds to tensile stress, a fourth stress adjustment layer 34 formed above the second moisture-proof layer 3b where the film stress of the first layered film 33, from the lower face film 10, corresponds to tensile stress, the TFT layer 4, the organic EL element layer 5, and the sealing layer 6.
Note that in the present embodiment, the fourth stress adjustment layer 34 may be formed of silicon oxynitride (SiNxOy), however no such limitation is intended. The fourth stress adjustment layer 34 may be formed of a silicon nitride (SiNx), a polyimide resin, or an organic film, for example, as long as the fourth stress adjustment layer 34 can be formed with the film stress of the first layered film 33, from the lower face film 10, that includes the fourth stress adjustment layer 34 corresponding to tensile stress.
To make the amount of compressive stress of the first layered film 33, from the lower face film 10 when the first regions R1, R2 are bend inward, that includes the fourth stress adjustment layer 34 and the amount of tensile stress of the first layered film 33, from the lower face film 10 in state before the first regions R1, R2 are bent, that includes the fourth stress adjustment layer 34 approximately equal, the CVD deposition conditions and the film thickness can be adjusted in the case of the fourth stress adjustment layer 34 being formed of silicon oxynitride (SiNxOy) or silicon nitride (SiNx), and the material, film thickness, and cure conditions can be adjusted in the case of the fourth stress adjustment layer 34 being formed of a polyimide resin or an organic film.
According to the flexible organic EL display panel 2d illustrated in (a) of
In the case the flexible organic EL display panel 2d illustrated in (b) of
A second layered film 11b formed in the second region R3 includes the resin layer 12, the second moisture-proof layer 3b where film stress from the lower face film 10 corresponds to tensile stress, the first moisture-proof layer 3a where film stress from the lower face film 10 corresponds to compressive stress, the TFT layer 4, the organic EL element layer 5, and the sealing layer 6. The first moisture-proof layer 3a is a stress adjustment layer formed above the second moisture-proof layer 3b with the absolute value of the tensile stress of the first layered film 33 being greater than the absolute value of the film stress of the second layered film 11b.
The first moisture-proof layer 3a and the second moisture-proof layer 3b are formed with the amount of compressive stress of the first moisture-proof layer 3a, from the lower face film 10, provided in the flexible organic EL display panel 2d illustrated in (b) of
To make the amount of compressive stress of the first layered film 33, from the lower face film 10 when the first regions R1, R2 are bend inward, that includes the second moisture-proof layer 3b and the amount of tensile stress of the first layered film 33, from the lower face film 10 in state before the first regions R1, R2 are bent, that includes the second moisture-proof layer 3b approximately equal, the CVD deposition conditions and film thickness of the second moisture-proof layer 3b can be adjusted.
According to the flexible organic EL display panel 2d illustrated in (b) of
As illustrated in (a) of
The flexible organic EL display panel 2d illustrated in (a) of
As illustrated in (b) of
The flexible organic EL display panel 2d illustrated in (b) of
In addition, because the changes in the properties of the transistor elements (Tr) from the first regions R1, R2 to the second region R3 are subtle, display unevenness at the boundary portion between the first regions R1, R2 and the second region R3 can be suppressed.
(a) of
As illustrated in (a) of
The second layered film 11 is the same as the layered film 11 illustrated in
The second layered film 11 is formed with the film stress of the second layered film 11, from the lower face film 10, formed in the second region R3 of the flexible organic EL display panel 2d illustrated in (a) of
On the other hand, the film stress of the first layered film 33, from the lower face film 10, formed in the first regions R1, R2 of the flexible organic EL display panel 2d is tensile stress. In other words, the first layered film 33 is formed with the film stress of the first layered film 33, from the lower face film 10, formed in the first regions R1, R2 being tensile stress in a state before the first regions R1, R2 of the flexible organic EL display panel 2d are bent.
As illustrated in the drawings, the tensile stress of the first layered film 33, from the lower face film 10, in a state before the first regions R1, R2 are bent and the compressive stress of the first layered film 33, from the lower face film 10, caused by inward bending of the first regions R1, R2 counteract one another.
Accordingly, the first layered film 33 is preferably formed with the amount of the compressive stress of the first layered film 33, from the lower face film 10, caused by inward bending of the first regions R1, R2 and the amount of tensile stress of the first layered film 33, from the lower face film 10, in a state before the first regions R1, R2 are bent being approximately equal.
Thus, in the flexible organic EL display panel 2d, the transistor element (Tr) and/or the organic EL element provided in the first regions R1, R2 can be prevented from breaking when the first regions R1, R2 are bent inward in the case of the flexible organic EL display panel 2d being fixed to the housing 50 of the display device 70a.
In the display device 70a illustrated in (a) of
In the case the flexible organic EL display panel 2d illustrated in (a) of
The TFT layer 4b is different from the TFT layer 4 of the second layered film 11 formed in the second region R3 in that the TFT layer 4b includes fifth stress adjustment layers 18a, 20a. In other words, the TFT layer 4b includes, instead of the inorganic insulating film 18 and the inorganic insulating film 20 provided in the TFT layer 4, the fifth stress adjustment layers 18a, 20a where the film stress of the first layered film 33, from the lower face film 10, corresponds to tensile stress.
The fifth stress adjustment layers 18a, 20a can be formed similarly to the fourth stress adjustment layer 34 illustrated in (a) of
Note that in the present embodiment, to prevent a large difference between the element properties of the transistor elements (Tr) provided in the first regions R1, R2 and the element properties of the transistor elements (Tr) provided in the second region R3 from forming, the fifth stress adjustment layers 18a, 20a are inorganic films formed of silicon oxynitride (SiNxOy), however no such limitation is intended. The fifth stress adjustment layers 18a, 20a may be formed of a silicon nitride (SiNx), a polyimide resin, or an organic film, for example, as long as the fifth stress adjustment layers 18a, 20a can be formed with the film stress of the first layered film 33, from the lower face film 10, that includes the fifth stress adjustment layer 18a, 20a corresponding to tensile stress.
To make the amount of compressive stress of the first layered film 33, from the lower face film 10 when the first regions R1, R2 are bend inward, that includes the fifth stress adjustment layers 18a, 20a and the amount of tensile stress of the first layered film 33, from the lower face film 10 in state before the first regions R1, R2 are bent, that includes the fifth stress adjustment layers 18a, 20a approximately equal, the CVD deposition conditions and the film thickness can be adjusted in the case of the fifth stress adjustment layers 18a, 20a being formed of silicon oxynitride (SiNxOy) or silicon nitride (SiNx), and the material, film thickness, and cure conditions can be adjusted in the case of the fifth stress adjustment layers 18a, 20a being formed of a polyimide resin or an organic film.
Note that the present embodiment is an example in which the fifth stress adjustment layer 18a, 20a is formed of two layers, however no such limitation is intended. The fifth stress adjustment layers 18a, 20a may be formed of one layer or three or more layers, for example, as long as the fifth stress adjustment layers 18a, 20a can be formed with the film stress of the first layered film 33, from the lower face film 10, that includes the fifth stress adjustment layers 18a, 20a corresponding to tensile stress.
According to the flexible organic EL display panel 2d illustrated in (a) of
In the case the flexible organic EL display panel 2d illustrated in (b) of
The sealing layer 6b is different from the sealing layer 6 of the second layered film 11 formed in the second region R3 in that the sealing layer 6b includes sixth stress adjustment layers 26a, 28a. In other words, the sealing layer 6b includes, instead of the first inorganic sealing film 26 and the second inorganic sealing film 28 provided in the sealing layer 6, the sixth stress adjustment layers 26a, 28a where the film stress of the first layered film 33, from the lower face film 10, corresponds to tensile stress.
The sixth stress adjustment layers 26a, 28a can be formed similarly to the fourth stress adjustment layer 34 illustrated in (a) of
Note that in the present embodiment, to prevent a large difference between the reliability of the transistor elements (Tr) and the organic EL elements provided in the first regions R1, R2 and the reliability of the transistor elements (Tr) and the organic EL elements provided in the second region R3 from forming, the sixth stress adjustment layers 26a, 28a are inorganic films formed of silicon oxynitride (SiNxOy), however no such limitation is intended. The sixth stress adjustment layers 26a, 28a may be formed of a silicon nitride (SiNx), a polyimide resin, or an organic film, for example, as long as the sixth stress adjustment layers 26a, 28a can be formed with the film stress of the first layered film 33, from the lower face film 10, that includes the sixth stress adjustment layers 26a, 28a corresponding to tensile stress.
To make the amount of compressive stress of the first layered film 33, from the lower face film 10 when the first regions R1, R2 are bend inward, that includes the sixth stress adjustment layers 26a, 28a and the amount of tensile stress of the first layered film 33, from the lower face film 10 in state before the first regions R1, R2 are bent, that includes the sixth stress adjustment layers 26a, 28a approximately equal, the CVD deposition conditions and the film thickness can be adjusted in the case of the sixth stress adjustment layers 26a, 28a being formed of silicon oxynitride (SiNxOy) or silicon nitride (SiNx), and the material, film thickness, and cure conditions can be adjusted in the case of the sixth stress adjustment layers 26a, 28a being formed of a polyimide resin or an organic film.
Note that the present embodiment is an example in which the sixth stress adjustment layers 26a, 28a is formed of two layers, however no such limitation is intended. The sixth stress adjustment layers 26a, 28a may be formed of one layer or three or more layers, for example, as long as the sixth stress adjustment layers 26a, 28a can be formed with the film stress of the first layered film 33, from the lower face film 10, that includes the sixth stress adjustment layers 26a, 28a corresponding to tensile stress.
According to the flexible organic EL display panel 2d illustrated in (b) of
Next, the third embodiment according to the present invention will be described with reference to
The single display region DA of the flexible organic EL display panel 2e illustrated in (a) of
The first regions RA, RB are located at or near the edge of the display region DA in the left-right direction of the drawing. In the first regions RA, RB, the first layered film 31 is formed with the amount of the tensile stress of the first layered film 31, from the lower face film 10, caused by outward bending of the first regions RA, RB and the amount of compressive stress of the first layered film 31, from the lower face film 10, in a state before the first regions RA, RB are bent being approximately equal.
The first region RC is a region centrally located in the display region DA in the left-right direction of the drawings. In the first region RC, two of the first layered films 31 are formed on either side of a single first layered film 33. In other words, the first layered films 31, 33 formed in the first region RC include a region where the film stress corresponds to compressive stress and a region where the film stress corresponds to tensile stress in a state before the flexible organic EL display panel 2e is bent.
The first layered film 31 is formed with the amount of the tensile stress of the first layered film 31, from the lower face film 10, caused by outward bending of the first region RC and the amount of compressive stress of the first layered film 31, from the lower face film 10, in a state before the first region RC is bent being approximately equal.
Also, the first layered film 33 is formed with the amount of the compressive stress of the first layered film 33, from the lower face film 10, caused by inward bending of the first region RC and the amount of tensile stress of the first layered film 33, from the lower face film 10, in a state before the first region RC is bent being approximately equal.
The single display region DA of the flexible organic EL display panel 2f illustrated in (b) of
The first regions RA, RB are located at or near the edge of the display region DA in the left-right direction of the drawing. In the first regions RA, RB, the first layered film 33 is formed with the amount of the compressive stress of the first layered film 33, from the lower face film 10, caused by inward bending of the first regions RA, RB and the amount of tensile stress of the first layered film 33, from the lower face film 10, in a state before the first regions RA, RB are bent being approximately equal.
The first region RC is a region centrally located in the display region DA in the left-right direction of the drawings. In the first region RC, two of the first layered films 33 are formed on either side of a single first layered film 31. In other words, the first layered films 31, 33 formed in the first region RC include a region where the film stress corresponds to compressive stress and a region where the film stress corresponds to tensile stress in a state before the flexible organic EL display panel 2f is bent.
The first layered film 33 is formed with the amount of the compressive stress of the first layered film 33, from the lower face film 10, caused by inward bending of the first region RC and the amount of tensile stress of the first layered film 33, from the lower face film 10, in a state before the first region RC is bent being approximately equal.
Also, the first layered film 31 is formed with the amount of the tensile stress of the first layered film 31, from the lower face film 10, caused by outward bending of the first region RC and the amount of compressive stress of the first layered film 31, from the lower face film 10, in a state before the first region RC is bent being approximately equal.
The single display region DA of the flexible organic EL display panel 2g illustrated in (c) of
The first regions RD, RF are located at or near the edge of the display region DA in the up-down direction of the drawing. In the first regions RD, RF, the first layered film 31 is formed with the amount of the tensile stress of the first layered film 31, from the lower face film 10, caused by outward bending of the first regions RD, RF and the amount of compressive stress of the first layered film 31, from the lower face film 10, in a state before the first regions RD, RF are bent being approximately equal.
The first region RE is a region centrally located in the display region DA in the up-down direction of the drawings. In the first region RE, two of the first layered films 31 are formed on either side of a single first layered film 33. In other words, the first layered films 31, 33 formed in the first region RE include a region where the film stress corresponds to compressive stress and a region where the film stress corresponds to tensile stress in a state before the flexible organic EL display panel 2g is bent.
The first layered film 31 is formed with the amount of the tensile stress of the first layered film 31, from the lower face film 10, caused by outward bending of the first region RE and the amount of compressive stress of the first layered film 31, from the lower face film 10, in a state before the first region RE is bent being approximately equal.
Also, the first layered film 33 is formed with the amount of the compressive stress of the first layered film 33, from the lower face film 10, caused by inward bending of the first region RE and the amount of tensile stress of the first layered film 33, from the lower face film 10, in a state before the first region RE is bent being approximately equal.
The single display region DA of the flexible organic EL display panel 2h illustrated in (d) of
The first regions RD, RF are located at or near the edge of the display region DA in the up-down direction of the drawing. In the first regions RD, RF, the first layered film 33 is formed with the amount of the compressive stress of the first layered film 33, from the lower face film 10, caused by inward bending of the first regions RD, RF and the amount of tensile stress of the first layered film 33, from the lower face film 10, in a state before the first regions RD, RF are bent being approximately equal.
The first region RE is a region centrally located in the display region DA in the up-down direction of the drawings. In the first region RE, two of the first layered films 33 are formed on either side of a single first layered film 31. In other words, the first layered films 31, 33 formed in the first region RE include a region where the film stress corresponds to compressive stress and a region where the film stress corresponds to tensile stress in a state before the flexible organic EL display panel 2h is bent.
The first layered film 33 is formed with the amount of the compressive stress of the first layered film 33, from the lower face film 10, caused by inward bending of the first region RE and the amount of tensile stress of the first layered film 33, from the lower face film 10, in a state before the first region RC is bent being approximately equal.
Also, the first layered film 31 is formed with the amount of the tensile stress of the first layered film 31, from the lower face film 10, caused by outward bending of the first region RE and the amount of compressive stress of the first layered film 31, from the lower face film 10, in a state before the first region RC is bent being approximately equal.
As described above, the flexible organic EL display panel 2e, 2f, 2g, 2h of the present embodiments includes both the inward bending region and the outward bending region in the single display region DA. The transistor element (Tr) and the organic EL element provided in this region can be prevented from breaking in the case of the flexible organic EL display panel being fixed to the housing 80, 81, 82, 83 of the display device 90, 91, 92, 93 with the flexible organic EL display panel being bent in a predetermined direction in this region.
The display devices 90, 91, 92, 93 illustrated in (a) of
To solve the problems described above, a display device according to a first aspect of the present invention includes:
a flexible display panel including a lower face film and a layered film, the layered film being formed above the lower face film and including a resin layer, a moisture-proof layer, a TFT layer, a display element layer, and a sealing layer; and
a housing, wherein
the housing includes a curved face region with curvature and a planar face region; a stress adjustment layer is provided in the layered film in a first region of the flexible display panel, the first region overlapping the curved face region, or in the layered film in a second region of the flexible display panel, the second region overlapping the planar face region; and
when curvature of the flexible display panel is zero, an absolute value of film stress of a first layered film is greater than an absolute value of film stress of a second layered film, the first layered film being all layered film that is formed above the lower face film and includes the layered film in the first region, and the second layered film being all layered film that is formed above the lower face film and includes the layered film in the second region.
The display device according to a second aspect of the present invention is a display device according to the first aspect, wherein the film stress of the first layered film is compressive stress.
The display device according to a third aspect of the present invention is a display device according to the first aspect, wherein the film stress of the first layered film is tensile stress.
The display device according to a fourth aspect of the present invention is a display device according to the second aspect, wherein the flexible display panel is fixed to the housing and bent in a direction opposite an increasing direction of a thickness of the first layered film of the flexible display panel, with, in the first region, the film stress of the first layered film due to bending of the flexible display panel corresponding to tensile stress.
The display device according to a fifth aspect of the present invention is a display device according to the third aspect, wherein the flexible display panel is fixed to the housing and bent in an increasing direction of a thickness of the first layered film of the flexible display panel, with, in the first region, the film stress of the first layered film due to bending of the flexible display panel corresponding to compressive stress.
The display device according to a sixth aspect of the present invention is a display device according to the second or fourth aspect, wherein the stress adjustment layer is formed above the moisture-proof layer with the film stress of the first layered film corresponding to the compressive stress when, in the first layered film, the curvature of the flexible display panel is zero.
The display device according to a seventh aspect of the present invention is a display device according to the second or fourth aspect, wherein, in the second layered film, the stress adjustment layer is formed above the moisture-proof layer with an absolute value of the compressive stress of the first layered film being greater than an absolute value of film stress of the second layered film when the curvature of the flexible display panel is zero.
The display device according to an eighth aspect of the present invention is a display device according to the sixth aspect, wherein the stress adjustment layer is formed as a plurality of island shapes in a slit pattern.
The display device according to a ninth aspect of the present invention is a display device according to the eighth aspect, wherein a width of the plurality of island shapes in a slit pattern in a direction orthogonal to a longitudinal direction of the plurality of island shapes in a slit pattern decreases toward the second region.
The display device according to a tenth aspect of the present invention is a display device according to the second or fourth aspect, wherein the stress adjustment layer is formed in the TFT layer with the film stress of the first layered film corresponding to the compressive stress when, in the first layered film, the curvature of the flexible display panel is zero.
The display device according to an eleventh aspect of the present invention is a display device according to the second or fourth aspect, wherein the stress adjustment layer is formed in the sealing layer with the film stress of the first layered film corresponding to the compressive stress when, in the first layered film, the curvature of the flexible display panel is zero.
The display device according to a twelfth aspect of the present invention is a display device according to the third or fifth aspect, wherein the stress adjustment layer is formed above the moisture-proof layer with the film stress of the first layered film corresponding to the tensile stress when, in the first layered film, the curvature of the flexible display panel is zero.
The display device according to a thirteenth aspect of the present invention is a display device according to the third or fifth aspect, wherein, in the second layered film, the stress adjustment layer is formed above the moisture-proof layer with an absolute value of the tensile stress of the first layered film being greater than an absolute value of film stress of the second layered film when the curvature of the flexible display panel is zero.
The display device according to a fourteenth aspect of the present invention is a display device according to the twelfth aspect, wherein the stress adjustment layer is formed as a plurality of island shapes in a slit pattern.
The display device according to a fifteenth aspect of the present invention is a display device according to the fourteenth aspect, wherein a width of the plurality of island shapes in a slit pattern in a direction orthogonal to a longitudinal direction of the plurality of island shapes in a slit pattern decreases toward the second region.
The display device according to a sixteenth aspect of the present invention is a display device according to the third or fifth aspect, wherein the stress adjustment layer is formed in the TFT layer with the film stress of the first layered film corresponding to the tensile stress when, in the first layered film, the curvature of the flexible display panel is zero.
The display device according to a seventeenth aspect of the present invention is a display device according to the third or fifth aspect, wherein the stress adjustment layer is formed in the sealing layer with the film stress of the first layered film corresponding to the tensile stress when, in the first layered film, the curvature of the flexible display panel is zero.
The display device according to an eighteenth aspect of the present invention is a display device according to any one of the first to seventeenth aspect, wherein, in the flexible display panel, two of the first regions are disposed on either side of one of the second regions.
The display device according to a nineteenth aspect of the present invention is a display device according to any one of the first to seventeenth aspect, wherein, in the flexible display panel, one of the first regions is disposed surrounding one of the second regions.
The display device according to a twentieth aspect of the present invention is a display device according to the first aspect, wherein the flexible display panel includes a plurality of the second regions and a plurality of the first regions, each one of the plurality of the second regions being disposed between the plurality of the first regions;
the first layered film is formed in a first region, of the plurality of the first regions, disposed between two of the plurality of the second regions; and
the first layered film includes a region where film stress is compressive stress and a region where film stress is tensile stress.
The present invention is not limited to each of the embodiments described above, and various modifications may be made within the scope of the claims. Embodiments obtained by appropriately combining technical approaches disclosed in each of the different embodiments also fall within the technical scope of the present invention. Moreover, novel technical features can be formed by combining the technical approaches disclosed in the embodiments.
The present invention can be utilized for a display device.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2018/007525 | 2/28/2018 | WO | 00 |
