Patent Grant
12178109
The disclosure relates to a display device.
As to the above display device, use of, for example, the secondary ion mass spectrometry (SIMS) is known to inspect for deterioration of the analysis layer formed of a plurality of organic layers including the light-emitting layer.
If SIMS, which involves emitting ions, is applied to a known display device, charges are gradually accumulated in the analysis layer. Because of the accumulated charges, the deterioration inspection might not be conducted appropriately. In particular, if the display device is used for, for example, a mobile device and includes a small display element (a display pixel), the analysis element (the analysis layer) is also small. Hence, the charges are accumulated in the analysis layer for a short time, making it difficult to appropriately conduct the deterioration inspection.
In view of the above problems, the disclosure is intended to provide a display device to be appropriately and readily inspected for deterioration even if the display element is downsized.
A display device according to an aspect of the disclosure includes: a display element provided to a display region; an analysis element provided to a frame region disposed around the display region; and a sealing layer sealing the display element and the analysis element. The display element includes: a TFT layer including a resin film; and a light-emitting element layer including a first electrode, a functional layer, and a second electrode. The analysis element includes: a first metal film formed on the resin film; an analysis layer formed on the first metal film; a second metal film formed to cover at least a portion of an edge of the analysis layer, and electrically connected to the first metal film; and a ground wire electrically connected through the first metal film to the second metal film.
An aspect of the disclosure makes it possible to appropriately and readily conduct an inspection for deterioration even if the display element is downsized.
In the description below, the term “same layer” means that constituent features are formed in the same process (in the same film deposition process). The term “lower layer (or layer below)” means that a constituent feature is formed in a previous process before a comparative layer is formed. The term “upper layer (or layer above)” means that a constituent feature is formed in a successive process after a comparative layer is formed.
An illustration (a) of
The display device 1 is a small panel to be used for such a mobile appliance as a smartphone. The display device 1 includes: a display region R1 provided with a plurality of display elements D (equivalent to a “display element” in claims) formed in a matrix; and a frame region R2 disposed around the display region R1 and provided with an analysis pixel T (equivalent to an “analysis element” of claims). The analysis pixel T is disposed closer to a terminal unit disposed in a portion of the frame region R2.
Each of the display pixels D includes: a sub-pixel DR that glows red; a sub-pixel DG that glows green; and a sub-pixel DB that glows blue. The analysis pixel T includes: an analysis sub-pixel TR corresponding to the sub-pixel DR; an analysis sub-pixel TG corresponding to the sub-pixel DG; and an analysis-sub-pixel TB corresponding to the sub-pixel DB.
When observed from a direction perpendicular to the display region R1, the analysis sub-pixel TR is larger than the sub-pixel DR, the analysis sub-pixel TG is larger than the sub-pixel DG, and the analysis sub-pixel TB is larger than the sub-pixel DB. When observed from the perpendicular direction, each of the analysis sub-pixels TR, TG, and TB is shaped into a square a side of which has a length “d” of 50 μm or longer.
The sub-pixel DR and the analysis sub-pixel TR are different in size in plan view but the same in structure. The sub-pixel DG and the analysis sub-pixel TG are also different in size in plan view but the same in structure. Moreover, the sub-pixel DB and the analysis sub-pixel TB are also different in size in plan view but the same in structure.
A base material 12 may be either a glass substrate, or a flexible substrate including a resin film such as polyimide. The flexible substrate may include: two resin films; and an inorganic insulating film sandwiched between the two resin films. A film made of, for example, polyethylene terephthalate may be attached to a lower surface of the base material 12. When the base material 12 is a flexible substrate, the display device 1 can be formed to be flexible.
A barrier layer 3 prevents such foreign objects as water and oxygen from reaching a thin-film transistor (TFT) layer 4 and a light-emitting element layer 5. An example of the barrier layer 3 includes a silicon oxide film, a silicon nitride film, or a silicon oxide nitride film formed by the chemical-vapor deposition (CVD), or a multilayer film including those films.
As illustrated in
The semiconductor layer is formed of, for example, amorphous silicon, low-temperature polysilicon (LIPS), or an oxide semiconductor. A thin-film transistor (TFT) TR is formed to include the gate electrode GE and the semiconductor film 15. In
In the display pixel D, each of the sub-pixels SP (DC, DR, and DB) is provided with: a light-emitting element Xr; and a control circuit for the light-emitting element Xr. The TFT layer 4 includes: the control circuit; and a wire connecting to the control circuit. The control circuit includes: a drive transistor to control a current of the light-emitting element Xr; a write transistor electrically connecting to a scanning signal line; and a light-emission control transistor electrically connecting to a light-emission control line.
The first metal layer, the second metal layer, and the third metal layer are each formed of a metal monolayer film or a metal multilayer film including at least one of, for example, aluminum, tungsten, molybdenum, tantalum, chromium, titanium, and copper.
The inorganic insulating films 16, 18, and 20 can be, for example, a silicon oxide (SiOx) film, or a silicon nitride (SiNx) film formed by the CVD, or a multilayer film including these films. The planarization film 21 may be made of an applicable organic material such as polyimide and acrylic resin.
The light-emitting element layer 5 includes: a first electrode (an anode) 22 above the planarization film 21; an edge cover film 23 (an edge cover) covering an edge of the first electrode 22 and providing insulation; an EL layer 24 (a functional layer) above the edge cover film 23; a second electrode (a cathode) 25 above the EL layer 24; and a Cap layer 27 above the second electrode 25. The edge cover film 23 is formed of, for example, an organic material such as polyimide and acrylic resin. The organic material is applied to the edge of the first electrode 22, and then patterned by photolithography to form the edge cover film 23.
The light-emitting element layer 5 includes the light-emitting element for including a plurality of light-emitting elements Xr. Each of the light-emitting elements Xr includes: the first electrode 22 shaped into an island; the EL layer 24 (including a light-emitting layer) shaped into an island; and the second electrode 25. The second electrode 25 is a monolithic common electrode formed in common among the light-emitting elements Xr.
Each light-emitting element Xr may be, for example, an organic light-emitting diode (OLED) including an organic layer as the light-emitting layer, or a quantum dot light-emitting-diode (QLED) including a quantum-dot layer as the light-emitting layer.
When the organic layer (the light-emitting layer) of the OLED is vapor-deposited, a fine metal mask (FMM) is used. The FMM is a sheet including many openings. Organic material passing through one opening forms an organic layer (corresponding to one sub-pixel) shaped into an island.
The quantum-dot layer (the light-emitting layer) of the QLED is formed of, for example, a solvent into which quantum dots are dispersed. The solvent is applied and then patterned by photolithography to form the quantum-dot layer (corresponding to one sub-pixel) shaped into an island.
The first electrode 22 (the anode) is, for example, a light-reflective multilayer formed of indium tin oxide (ITO) and silver (Ag), or of ITO and an alloy including Ag. The second electrode 25 (the cathode) is a light-transparent thin film formed of, for example, an Mg Ag alloy.
If the light-emitting element Xr is the OLED, holes and electrons recombine together in the tight-emitting layer by a drive current between the first electrode 22 and the second electrode 25, which forms an exciton. While the exciton transforms to the ground state, light is emitted. Because the second electrode 25 is highly transparent to light and the first electrode 22 is light-reflective, the light emitted from the EL layer 24 travels upward. This is how the light-emitting element layer 5 is of a top emission type.
If the light-emitting element Xr is the QLED, holes and electrons recombine together in the light-emitting layer by a drive current between the first electrode 22 and the second electrode 25, which forms an exciton. While the exciton transforms from the conduction band level to the valence band level of the quantum dots, light (fluorescence) is emitted.
The light-emitting element layer 5 may include a light-emitting element (e.g. an inorganic light-emitting diode) other than the MED and the QLED.
The sealing layer 6 is a light-transparent barrier layer including, for example, an inorganic insulating film and an organic insulating film. The sealing layer 6 prevents such foreign objects as water and oxygen from penetrating into the light-emitting element layer 5.
The functional film 39 has at least one of such functions as optical compensation, touch sensing, and protection.
In the planarization film 21, a trench 21t is formed. As shown in plan view in the illustration (a) of
In the frame region R2, the analysis sub-pixels TR, TG, and TB may be positioned closer to the trench 21t and either toward or away from the display region R1. Preferably, as shown in the illustration (b) of
An illustration (a) of
The analysis sub-pixels TR, TG, and TB are the same in cross-sectional structure. Representing these analysis sub-pixels, described here is the cross-sectional structure of the analysis sub-pixel TR. The analysis sub-pixel TR includes: a first metal film 22T formed on the planarization film 21; an analysis EL layer 24T (an analysis layer, or an analysis light-emitting layer) formed on the first metal layer 22T; a second metal film 25T formed on the first metal film 22T to cover the analysis EL layer 24T; and a Cap film 27T formed between the second metal film 251 and the sealing layer 6.
As shown in the illustration (b) of
The illustration (b) of
Furthermore, in the above description, the illustration (b) of
After that, as shown in the illustration (b) of
The analysis EL layer 241 is formed in the same layer, and of the same material, as the EL layer 24 of the sub-pixel DR is. The analysis EL layer 241 is larger in plan view than the EL layer 24. The analysis EL layer 24T includes an analysis light-emitting layer 30T corresponding to the light-emitting layer 30 of the EL layer 24. The first metal film 22T is formed in the same layer, and of the same material, as the first electrode 22 of the sub-pixel DR is. Preferably, the first metal film 22T is formed of ITO. For example, the first metal film 22T is of a three-layer multilayer structure of ITO/Ag/ITO, or ITO/AL/ITO. ITO may be replaced with IZO. The second metal film 25T is formed in the same layer, and of the same material, as the second electrode 25 is. Preferably, the second metal film 25T is formed of silver. The ground wire GW is formed in the same layer, and of the same material, as the first metal film 22T is.
The analysis sub-pixel TR is not provided with the edge cover film 23 so that the first metal film 22T is at least partially exposed.
When the analysis light-emitting layer 30T of the analysis EL layer 24T in the analysis sub-pixel TR (TG, or TB) is inspected for amount of deposition and deterioration by water and oxygen by the time-of-flight secondary ion mass spectrometry (TOE-SIMS), the sealing layer 6 is, as shown in the illustration (b) of
In the example shown in the illustration (a) of
The TOE-SIMS analyzer 41 includes: the sputter gun (a gas cluster ion beam or GCIB) 42 for digging the surface of the analysis EL layer 24T; the primary ion gun 43 emitting pulsed primary ions to the surface of the analysis EL layer 24T; and a detector 44 catching secondary ions 45 ejected, from the surface of the analysis EL layer 24T, by the emitted pulsed primary ions.
This TOF-SIMS analyzer 41 has specifications below:
The TOF-SIMS analyzer 41 of the above configuration analyzes the analysis EL layer 24T as described below.
First, as shown in the illustrations (a) and (b) of
Next, as shown in the illustration (a) of
Next, the process of the illustrations (a) to (c) is repeated. On the basis of the spectrum analysis according to mass, a composition profile is obtained for each of the layers of the analysis EL layer 241. Each obtained composition profile is several nanometers long along the depth of the analysis EL layer 24T.
Preferably, the analysis EL layer 24T is formed on a flat place. The flat place can keep the surface of the analysis EL layer 24T from being angled. As a result, when the TOF-SIMS analyzer 41 analyses the analysis EL layer 24T, the sputter gun 42 can be kept from digging a wrong layer on the surface of the analysis EL layer 24T, making it possible to conduct the analysis appropriately and readily.
An illustration (a) of
The analysis sub-pixel 9TR includes: a first metal film 92T formed on the planarization film 21; an analysis EL layer 941 formed on the first metal film 92T; a second metal film 95T formed on the analysis EL layer 94T; and a Cap film 97T formed between the second metal film 95T and a sealing layer 96.
When the analysis EL layer 94T of the analysis sub-pixel 9TR (910, or 9TB) has a light-emitting layer inspected for deterioration by the TOF-SIMS, the sealing layer 96 is, as shown the illustration (b) of
In this comparative example, when the analysis EL layer 94T is treated with the sputter gun 42 and the primary ion gun 43, charges are accumulated on the surface of the analysis EL layer 94T. The amount of the charges to be accumulated on the surface of the analysis EL layer 94T increases as the sputtering time proceeds. Hence, a problem of the comparative example is that, as the sputtering time proceeds, a profile of an intensity signal according to the mass-separation is disturbed. Consequently, output of the intensity signal stops.
In this embodiment, when the analysis EL layer 24T is treated with the sputter gun 42 and the primary ion gun 43, charges accumulated on the surface of the analysis EL layer 24T can be dissipated through the second metal film 25T, the first metal film 221, and the ground wire GW. Such a feature can reduce the risk that the charges are accumulated on the surface of the analysis EL layer 241 during the analysis. Hence, the feature can solve the problems of (i) the charges accumulated in a shorter period of time when an analysis element (an analysis layer) is downsized as a display element is downsized, and (ii) the resulting difficulty in appropriate inspection for deterioration. As a result, the feature makes it possible to appropriately and readily conduct an inspection for deterioration even if the display device is downsized.
An illustration (a) of
As seen in an area “B” of the illustration (b) of
In contrast, as seen in the illustration (a) of
An illustration (a) of
As seen in an area “C” of the illustration (b) of
In contrast, as seen in the illustration (a) of
An illustration (a) of
As seen in the illustration (b) of
In contrast, as seen in the illustration (a) of
An intensity signal S1 in the illustration of
This embodiment shows an example that the TOF-SIMS analyzer 41 analyzes the analysis sub-pixel TR. However, the disclosure shall not be limited to this example. The disclosure is applicable to analysis techniques in which the charges are gradually accumulated on an object to be analyzed, such as, for example, analyses by Auger electron spectroscopy (AES) and irradiation with ions.
A display device according to a first aspect includes: a display element provided to a display region; an analysis element provided to a frame region disposed around the display region; and a sealing layer sealing the display element and the analysis element. The display element includes: a TFT layer including a resin film; and a light-emitting element layer including a first electrode, a functional layer, and a second electrode. The analysis element includes: a first metal film formed on the resin film; an analysis layer formed on the first metal film; a second metal film formed to cover at least a portion of an edge of the analysis layer, and electrically connected to the first metal film; and a ground wire electrically connected through the first metal film to the second metal film.
In a second aspect, the analysis layer may be formed in the same layer, and of the same material, as the functional layer is.
In a third aspect, the functional layer may include a light-emitting layer, and >the analysis layer may include an analysis light-emitting layer corresponding to the light-emitting layer.
In a fourth aspect, the display element may include a plurality of sub-pixels having the functional layer including a plurality of the light-emitting layers each emitting light in a different color. The analysis pixel may include a plurality of analysis sub-pixels each corresponding to one of the sub-pixels, each of the analysis sub-pixels including a corresponding one of a plurality of analysis light-emitting layers each corresponding to one of the light-emitting layers.
In a fifth aspect, the analysis layer may be larger in plan view than the functional layer.
In a sixth aspect, the first metal film may be formed in the same layer, and of the same material, as the first electrode is.
In a seventh aspect, the first metal film may contain ITO.
In an eighth aspect, the second metal film may be formed in the same layer, and of the same material, as the second electrode is.
In a ninth aspect, the second metal film may contain silver,
In a tenth aspect, the light-emitting element layer may further include an edge cover covering an edge of the first electrode and having an opening to expose the first electrode. The analysis element does not have to be provided with the edge cover so that the first metal film is at least partially exposed.
In an eleventh aspect, the ground wire may be formed in the same layer, and of the same material, as the first metal film is.
In a twelfth aspect, the ground wire may intersect with, and extend out of, the sealing layer.
In a thirteenth aspect, the second metal film may be formed to cover a whole surface of the analysis layer.
In a fourteenth aspect, the display element may include a plurality of sub-pixels having the functional layer including a plurality of the light-emitting layers each emitting light in a different color. The analysis pixel may include a plurality of analysis sub-pixels each corresponding to one of the sub-pixels, each of the analysis sub-pixels including a corresponding one of a plurality of analysis light-emitting layers each corresponding to one of the light-emitting layers. The second metal film may be formed to cover one of four side edges of each of the analysis light-emitting layers of the analysis sub-pixels.
In fifteenth aspect, the second metal film may be formed in the same layer, and of the same material, as the second electrode is.
In a sixteenth aspect, the second metal film may contain silver.
The disclosure shall not be limited to the embodiment described above, and can be modified in various manners within the scope of claims. For example, the technical aspects disclosed in different embodiments are to be appropriately combined together to implement another embodiment. Such an embodiment shall be included within the technical scope of the disclosure. Moreover, the technical aspects disclosed in each embodiment may be combined to achieve a new technical feature.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2019/003886 | 2/4/2019 | WO |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2020/161774 | 8/13/2020 | WO | A |
| Number | Name | Date | Kind |
|---|---|---|---|
| 20110133636 | Matsuo | Jun 2011 | A1 |
| 20200373367 | Okabe | Nov 2020 | A1 |
| Number | Date | Country |
|---|---|---|
| 11311611 | Nov 1999 | JP |
| H11311611 | Nov 1999 | JP |
| 2018003356 | Jan 2018 | JP |
| 2018098070 | Jun 2018 | JP |
| Number | Date | Country | |
|---|---|---|---|
| 20220093703 A1 | Mar 2022 | US |
