JP4848600B2 - Display element and display device using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a plurality of display elements or display units and a display device or display using the same, and more particularly to a display element suitable for a display using a self-luminous display element and a display device using the same.
[0002]
[Background]
Recently, liquid crystal displays have become very popular and have features such as low voltage drive, low power consumption, miniaturization and thinning, etc., such as televisions, PCs (personal computers), portable information devices, mobile phones, watches, calculators, etc. Is widely used in various products.
[0003]
However, since this liquid crystal display is not self-luminous, a backlight is required to obtain a bright image. A reflective liquid crystal display that does not require a backlight has been studied, but a sufficiently satisfactory contrast has not been obtained. In addition, liquid crystal displays are not suitable for large displays because of their narrow viewing angles. Furthermore, since the display method is based on the alignment state of the liquid crystal molecules, the contrast changes depending on the angle even within the viewing angle, and the dynamic range at the time of alignment change cannot be widened, so it is not suitable for moving image display. There are also inconveniences.
[0004]
On the other hand, recently, a self-luminous display, specifically, a display using a plasma display element, an inorganic electroluminescent element, an organic electroluminescent element or the like has attracted attention. A self-luminous display
(1) Wide viewing angle compared to liquid crystal elements,
(2) Good contrast and excellent visibility.
(3) Since no backlight is required, it can be made thinner and lighter.
It is suitable for large displays.
[0005]
[Problems to be solved by the invention]
However, when obtaining a large display, the size of the display element (display panel) per substrate is limited due to restrictions on the manufacturing process. For example, when an organic electroluminescent element is used, the element is formed on a glass substrate on which a conductive electrode is formed by a vacuum deposition method using a low molecule, a spin coating method using a polymer, a printing method, an ink jet method, or the like. However, in any of these methods, the size of the display element is limited. Further, in the case of a large screen, a decrease in yield when a defect occurs in a part of the screen is unavoidable, and it is difficult to ensure in-plane uniformity. Therefore, as a method for obtaining a large-screen display, a method of bonding a plurality of display elements can be considered. However, in this method, it is important that the boundary between adjacent display element units is not conspicuous.
[0006]
The present invention pays attention to the above points, and an object of the present invention is to provide a pixel (pixel) configuration capable of making the boundary of bonding in a display having a divided screen configuration inconspicuous. Another object is to widen the margin in bonding. Still another object is to reduce deterioration from a bonded portion, particularly when an organic electroluminescent element is used.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a display element in which one unit pixel is composed of a plurality of sub-pixels, and a plurality of the sub-pixels are bonded together to obtain a large-screen display. Sub-pixels are formed in the vicinity of the boundary so as to constitute one unit pixel across the bonding boundary . In addition, the number of subpixels included in a pixel located on the bonding boundary of the display element is smaller than the number of subpixels included in other pixels not positioned on the bonding boundary.
[0008]
According to the present invention, one unit pixel includes a plurality of sub-pixels. At the bonding boundary of the display elements, the pixels are configured so that the subpixels sandwich the boundary. Accordingly, the boundary of the display element passes through the center of the pixel and becomes inconspicuous, and a sufficient margin for bonding can be obtained. The above and other objects, features and advantages of the present invention will become apparent from the following detailed description and the accompanying drawings.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
<Embodiment 1> First, a first embodiment of the present invention will be described with reference to FIG. 1 and FIG. In this embodiment, as shown in FIG. 2 (A), a large-screen display is formed by adjoining display elements (display panels) 20 and 30 on a glass substrate (glass substrate) 10 for bonding. It is something to get. A side view seen from the direction of arrow F20 is as shown in FIG.
[0010]
The basic structures of the display elements 20 and 30 are the same, and element layers 24 and 34 including organic electroluminescent layers are provided on transparent glass substrates 22 and 32. The adhesive 12 is applied to the surfaces of the element layers 24 and 34, and the display elements 20 and 30 are bonded on the glass substrate 10 so that the bonding surfaces 26 and 36 are in contact with each other. As the adhesive 12, an ultraviolet curable resin such as an epoxy resin is used. From each of the display elements 20 and 30, image light is output from the glass substrates 22 and 32 side as indicated by an arrow F22.
[0011]
An enlarged view of the layered structure of the pixel portions of the element layers 24 and 34 is as shown in FIG. A large number of transparent anode electrodes 101 are formed in a stripe pattern on the glass substrates 22 and 32 by sputtering. In the glass substrate 32, the stripe width of the transparent anode electrode 101 adjacent to the bonding surface 36 is formed narrower than the stripe width of the other transparent anode electrodes 101.
[0012]
Next, a hole injection layer 102, a hole transport layer 104, a light emitting layer 106, and an electron transport layer 108 are sequentially stacked on the transparent anode electrode 101 by a vacuum deposition method. As a result, the organic electroluminescent layer 100 is obtained. On the electron transport layer 108, a cathode electrode 112 and a protective layer (passivation film) 114 are laminated and formed by vacuum deposition or sputtering, respectively. Note that a hole-transporting light-emitting layer may be used instead of the hole-transporting layer 104 and the light-emitting layer 106, and an electron-transporting light-emitting layer may be used instead of the electron-transporting layer 108 and the light-emitting layer 106. Further, the electrode and each layer may be formed as a single layer with one material, or may be a laminated structure with a plurality of materials. Specific examples of these layers will be described later.
[0013]
A pixel configuration of the display elements 20 and 30 is shown in FIG. FIG. 2A shows a state before bonding. In the display elements 20 and 30, pixels P20 and P30 are formed on the glass substrates 22 and 32 at regular intervals, respectively. Among these, the pixel P20 is composed of two subpixels P20a and P20b, and the pixel P30 is composed of two subpixels P30a and P30b. A subpixel P22a is provided in a portion adjacent to the bonding surface 26 of the display element 20, and a subpixel P32b is provided on the bonding surface 36 side of the display element 30. Margins at these joint surfaces 26 and 36 are W22 and W32, respectively.
[0014]
When these display elements 20 and 30 are bonded together as shown in FIG. 2, the result is as shown in FIG. That is, at the boundary 27, the subpixel P22a and the subpixel P32b are adjacent to each other. In this embodiment, one unit of pixel P23 is constituted by these adjacent subpixels P22a and P32b. Therefore, the boundary 27 between the display elements 20 and 30 passes through the center of the pixel P23 and becomes almost unnoticeable. For this reason, it becomes possible to obtain sufficient margins W22 and W32 for bonding the display elements 20 and 30 at the boundary 27, so that the bonding operation can be performed with a margin. In addition, the organic electroluminescent element is severely deteriorated by moisture or oxygen due to its properties, but by taking a sufficient margin at the boundary 27, the element and the outside air can be well sealed, and the bonding is performed. Deterioration from the part is reduced.
[0015]
Note that the sub-pixels constituting each pixel are driven simultaneously, for example. Simultaneous driving can be realized by commonly connecting electrode patterns between sub-pixels or providing TFT circuits in common among sub-pixels. However, simultaneous driving may be performed by a driving circuit. For example, as shown in FIG. 1B, when the pixels P20, P23, and P30 are driven by the scanning line driving circuit 14 and the data line driving circuit 16, the sub-pixels P20a, P20b, and P22a are connected to the data line driving circuit 16, respectively. A simultaneous drive circuit 18 for simultaneously driving P32b, P30a and P30b is provided.
[0016]
<Embodiment 2> Next, Embodiment 2 will be described with reference to FIG. In addition, the same code | symbol is used for the component corresponding to Embodiment 1 mentioned above. In the first embodiment, one unit pixel is configured by two adjacent subpixels. However, in this embodiment, one unit pixel is configured by three subpixels.
[0017]
First, in the example shown in FIG. 3A, in the display element 40, one unit of pixel P40 is formed by the subpixels P40a, P40b, and P40c, and in the display element 50, one unit of pixel P40a, P50b, and P50c is used. Pixel P50 is configured. Further, adjacent to the boundary 27, a subpixel P42a is provided on the display element 40 side, and subpixels P52b and P52c are provided on the display element 50 side. These subpixels P42a, P52b, and P52c constitute one unit of pixel P45. Note that two subpixels may be provided on the display element 40 side and one subpixel may be provided on the display element 50 side with the boundary 27 interposed therebetween.
[0018]
Next, the embodiment of FIG. 3B has a configuration in which the number of subpixels included in the pixels located on the boundary 27 is smaller than the number of subpixels of other pixels. That is, in the example in which one subpixel is removed from the pixels on the boundary in the embodiment of FIG. 3A, the subpixel P42a adjacent to the boundary 27 of the display element 41 and the subpixel adjacent to the boundary 27 of the display element 51 are displayed. One unit of pixel P46 is constituted by the pixel P52c. Since the number of subpixels included in the pixel P46 is one less than that of the other pixels P40 and P50, the margins W41 and W51 along the boundary 27 of the display elements 41 and 51 are made larger than in the embodiment of FIG. Can be taken. The margins W41 and W51 may be the same or different.
[0019]
Third Embodiment Next, a third embodiment will be described with reference to FIG. The embodiment described above is an example in which pixels are arranged in a stripe type, a mosaic type, or a square type, but this embodiment is an example of a delta type pixel arrangement. In FIG. 4, in the display element 60, one unit pixel P60 is constituted by subpixels P60a and P60b, and in the display element 70, one unit pixel P70 is constituted by subpixels P70a and P70b. Further, adjacent to the boundary 27, a subpixel P62a is provided every other horizontal line on the display element 60 side, and a subpixel P72b is provided every other horizontal line on the display element 70 side. These subpixels P62a and P72b constitute one unit of pixel P67. That is, the boundary 27 between the display elements 60 and 70 is configured to pass through the pixels every other horizontal line.
[0020]
The example of FIG. 4B is an example in which the example of FIG. 4A is applied to color display. There may be various modes as to which R (red), G (green), and B (blue) correspond to which pixel in a certain order, but in the example of FIG. The pixel P67 located on the boundary 27 is G.
[0021]
In the example of FIG. 4C, one unit pixel P80 constituting the display element 80 is constituted by four subpixels P80a to P80d, and one unit pixel P90 constituting the display element 90 is four subpixels. It is comprised by P90a-P90d. Further, adjacent to the boundary 27, subpixels P81a, P81a to P81c are alternately provided every other horizontal line on the display element 80 side, and subpixels P91b to P91b are arranged every other horizontal line on the display element 90 side. P91d and P91d are provided alternately. The subpixels P81a and P91b to P91d constitute one unit of pixel P89A, and the subpixels P81a to P81c and P91d constitute one unit of pixel P89B. According to this example, the boundary 27 of the display elements 80 and 90 passes through the pixels in any horizontal line. Of course, this example may also be applied to color display as shown in FIG.
[0022]
<Embodiment 4> Next, Embodiment 4 will be described with reference to FIG. This embodiment is an example in which the display elements 200, 210, 220, and 230 are bonded together as shown in FIG. In this example, as shown in FIG. 5B, one unit pixel P200 is constituted by four adjacent subpixels P200a, P200b, P200c, and P200d. The same applies to the boundaries of the display elements 200 to 230, and one unit pixel P202 is constituted by the four subpixels P202a, P202b, P202c, and P202d adjacent to the bonding surfaces or boundaries 240 and 242 of each panel. The same applies to the center of the panel with which the display elements 200 to 230 are in contact. According to this example, the panel boundary is located in the pixel both on the top, bottom, left, and right, and the boundary becomes inconspicuous even if a large margin is provided at the panel joint portion.
[0023]
<Embodiment 1> Next, an embodiment that is experimentally produced with respect to the present invention will be described. First, Example 1 will be described with reference to the cross section of the main part of FIG. 6A and the chemical structural formula of FIG. This example is an example of a passive drive type. A glass substrate 300 of 500 mm × 500 mm is prepared, and ITO having a film thickness of about 100 nm is formed thereon by sputtering. The ITO is patterned in a stripe shape using a wet etching technique. The stripe width is, for example, 500 μm, that is, a 500 μm subpixel pitch. Two lines of 500 μm ITO are treated as one unit pixel. Such striped ITO becomes the transparent anode electrode 302.
[0024]
Next, an organic electroluminescent layer is formed on the transparent anode electrode 302. First, m-MTDATA (4,4 ′, 4 ″ -tris (3-methylphenylphenylamino) triphenylamine, the structural formula is shown in FIG. 7A) is used as the hole injection layer 304 over the entire main surface of the substrate. The film is formed at a thickness of 2 to 0.4 nm / sec and 30 nm under vacuum by a vacuum deposition method. Next, α-NPD (α-naphtyl phenyl diamine, see FIG. 7B for the structural formula) is used as the hole transport layer 306 under vacuum by a vacuum deposition method at a deposition rate of 0.2 to 0.4 nm / sec. To 30 nm. Next, as the electron-transporting light-emitting layer 308, Alq ₃ (8-hydroxy quinorine alminum, see FIG. 7C for the structural formula) is vacuum-deposited by a vacuum deposition method at a deposition rate of 0.2 to 0.4 nm / sec. A 50 nm vapor deposition is formed below. The organic electroluminescent layer 310 is formed by the above layers.
[0025]
Next, the cathode electrode 312 is formed by vacuum deposition in a direction orthogonal to the stripe direction of the transparent anode electrode 302. That is, using a cathode electrode deposition mask in which slit-like openings having a width of 2 mm are arranged at a pitch of 1 mm, an Mg-Ag alloy (Mg: Ag = 9: 1 in film thickness ratio) is deposited at a deposition rate of 0 to 0. The cathode electrode 312 is obtained by depositing about 0.5 nm at 3 nm / sec. Next, as the cathode sealing layer 314, an Al—Cu alloy (Cu is 1 wt%) is deposited by 200 nm, and as the conductive sealing layer 316, an Au—Ge alloy (Ge is 12 wt%). Deposit 200 nm.
[0026]
Next, on the conductive sealing layer 316, as the inorganic sealing layer 318, SiNx is formed to a thickness of 2 μm by plasma CVD. Note that the inorganic sealing layer 318 is formed using a predetermined mask in addition to a portion where the transparent anode electrode 302 or the cathode electrode 312 contacts the external circuit.
[0027]
Bonding as shown in FIG. 2 is performed on the display element by the organic electroluminescence element matrix thus manufactured. A glass substrate of 900 mm × 450 mm is prepared as a glass substrate for bonding, and UV resin (ultraviolet curable resin) is applied thereon. The display element was placed on a glass substrate for bonding so that the area where the inorganic sealing layer 318 other than the contact was formed was in contact with the UV resin, and UV irradiation was performed to bond the two together. At this time, the test was performed under the condition of eliminating the flatness of the glass interface and the protrusion of the UV resin.
[0028]
At the junction boundary of the bonded organic electroluminescence matrix display produced in this way, the image was displayed so that the two sub-bixels sandwiching the interface would be one unit pixel. That is, matrix driving is performed in the embodiment as shown in FIG. As a result of observing the display image, it was possible to drive the display element without conspicuous the junction.
[0029]
Example 2 Next, Example 2 will be described with reference to FIGS. 6B, 7 and 8. In addition, the same code | symbol is used for the component corresponding to Example 1 mentioned above. This embodiment is an example applied to a TAC (TOP Emitting Adoptive Current Drive) display device. On a 300 mm × 350 mm evaluation low-temperature polysilicon TFT substrate 400, a pixel driving TFT 402 having a size basically the same as the above size is disposed. Then, thereon, to form a Cr layer as the anode electrode 404, a width 1 mm, the opening of the light emitting area of length 2 mm, are used to pattern Si0 _2. The basic pixel arrangement of this embodiment is the same as that of the first embodiment. In this embodiment, two subpixels formed as described above are treated as one unit pixel.
[0030]
Next, an organic electroluminescent layer is manufactured. A hole injection layer 304, a hole transport layer 306, and an electron transport light emission are formed on the main surface of the substrate so as to cover the light emitting area using a mask having a dot-type opening. Layers 308 are sequentially stacked. As a result, an organic electroluminescent layer 310 similar to that in Example 1 is obtained. Then, an Mg—Ag alloy (Mg: Ag = 9: 1 in a film thickness ratio) is deposited on the entire surface of the organic electroluminescent layer 310 so as to cover the light emitting surface of the organic electroluminescent layer 310 at a deposition rate of about 0.3 nm / sec. The cathode electrode 312 is obtained by 5 nm vapor deposition. Next, an inorganic sealing layer 318 is formed on the cathode electrode 312 in the same manner as in Example 1.
[0031]
The display device using the organic electroluminescence device matrix thus manufactured is bonded as shown in FIG. FIG. 8 shows a state at the time of bonding. A 300 mm × 500 mm glass substrate is prepared as the glass substrate 10 for bonding, and a UV resin (ultraviolet curable resin) 406 is applied thereon. In this example, since light output from the organic electroluminescent layer 310 is output to the outside through the UV resin 406, a transparent material is used even after curing by UV irradiation. Then, by placing the display elements 450 and 460 on the glass substrate 10 for bonding so that the area where the inorganic sealing layer 318 other than the contact is formed is in contact with the UV resin 406, UV irradiation is performed. Both were bonded together.
[0032]
In the bonding of the bonded organic electroluminescence matrix display produced in this way, the image was displayed so that the two sub-vicels sandwiching the interface would be one unit pixel. That is, matrix driving is performed in the embodiment as shown in FIG. As a result of observing the display image, it was possible to drive the display element without conspicuous the junction.
[0033]
The present invention has many embodiments, and various modifications can be made based on the above disclosure. For example, the following are included.
(1) In the above embodiment, the case where the pixels and sub-pixels are rectangular has been mainly described. However, various shapes such as a circle, an ellipse, and a polygon may be used. Further, the arrangement of pixels and sub-pixels may be changed as appropriate. The number of subpixels included in one pixel may be four or more.
(2) Each subpixel may of course be driven simultaneously, but this does not prevent non-simultaneous driving.
(3) As a material of each part, you may use various well-known things other than what was mentioned above. Further, each of the above-described layers may have a known laminated structure, and if necessary, a filter or a black matrix may be provided. In particular, it is effective to provide a filter or a black matrix so as to hide the bonding site.
(4) In the above-described embodiment, the base for bonding is used. However, only the display element may be bonded, and any bonding method may be applied.
(5) Although the said embodiment is an example which applied this invention to the display which uses an organic electroluminescent element, it is applicable similarly to the display which uses a plasma light emitting element and an inorganic electroluminescent element in addition. Further, the display driving method can be applied to either a passive type (simple matrix type) or an active type (TFT driving type). Furthermore, it can be applied to both color display and single color display (monochrome display).
[0034]
【The invention's effect】
As described above, the present invention has the following effects.
(1) Since the pixels in the display element are composed of a plurality of subpixels, and the subpixels sandwich the boundary at the bonding boundary of the display elements, the boundary becomes inconspicuous.
(2) Since the bonding boundary is not conspicuous, a large margin can be secured at the bonding site, and the bonding operation can be performed with a margin. In addition, the deterioration of the element from the bonded portion can be reduced.
[Brief description of the drawings]
FIG. 1 is a plan view showing a main part of a pixel configuration according to a first embodiment of the present invention.
FIG. 2 is a view showing a state of bonding and a laminated structure of an organic electroluminescent layer in the first embodiment.
FIG. 3 is a plan view showing a main part of a pixel configuration according to a second embodiment of the present invention.
FIG. 4 is a plan view showing a main part of a pixel configuration according to Embodiment 3 of the present invention.
FIG. 5 is a plan view showing a main part of a pixel configuration according to a fourth embodiment of the present invention.
FIG. 6 is a main cross-sectional view showing a laminated structure of organic electroluminescent layers in an example of the present invention.
FIG. 7 is a view illustrating a chemical structural formula of a main part of the organic electroluminescent layer.
8 is a cross-sectional view showing a schematic configuration of a TAC type of Example 2. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Glass substrate 12 ... Adhesive 14 ... Scan line drive circuit 16 ... Data line drive circuit 18 ... Simultaneous drive circuit 20,30,40,41,50,51,60,70,80,90,200,210,220 , 230 ... Display elements 22 and 32 ... Glass substrates 24 and 34 ... Element layers 27, 240 and 242 ... Boundaries 26 and 36 ... Bonding surface 100 ... Organic electroluminescent layer 101 ... Transparent anode electrode 102 ... Hole injection layer 104 ... Hole transport Layer 106 ... Light-emitting layer 108 ... Electron transport layer 112 ... Cathode electrode 114 ... Protective layer 300 ... Glass substrate 302 ... Transparent anode electrode 304 ... Hole injection layer 306 ... Hole transport layer 308 ... Electron transport light-emitting layer 310 ... Organic electroluminescent layer 312 ... Cathode electrode 314 ... Cathode electrode sealing layer 316 ... Conductive sealing layer 318 ... Inorganic sealing layer 400 ... Substrate 402 ... Pixel drive Use TFT
404 ... anode electrode 406 ... resin 450, 460 ... display element OLED ... organic electroluminescent elements P20, P23, P30, P40, P45, P46, P50, P60, P67, P70, P80, P90, P89A, P89B, P200, P202 ... Pixels P20a, P20b, P30a, P30b, P22a, P32b, P40a-P40c, P42a, P50a-P50c, P52b, P52c, P60a, P60b, P62a, P70a, P70b, P62a, P72b, P80a-P80d, P81a-P81c P90a to P90d, P90b to P90d, P200a to P200d, P202a to P202d ... subpixels

Claims (5)

1 and the unit pixel is composed of a plurality of sub-pixels, a display device for obtaining the display of a large screen by I if bonding a plurality, sandwiching the paste if I was a boundary of the display device 1 Forming sub-pixels near the boundary so as to constitute a unit pixel ;
The display element characterized in that the number of subpixels included in a pixel located on the bonding boundary of the display element is smaller than the number of subpixels included in another pixel not located on the bonding boundary . Display device according to claim 1, characterized in that the sub-pixels formed by the organic electroluminescent element. So that one unit pixel is a display device obtained by bonding a plurality of display elements which are composed of a plurality of sub-pixels constitute one unit of pixels adjacent to each other across the bonding if I was a boundary of the display device And forming subpixels in the vicinity of the bonding boundary of the display elements ,
The display device characterized in that the number of subpixels included in a pixel located on the bonding boundary of the display element is smaller than the number of subpixels included in another pixel not positioned on the bonding boundary . The display device according to claim 3, wherein the sub-pixel is formed of an organic electroluminescent element. With the single pixels by combining sub-pixels adjacent to each other across the bonding boundary, the display according to claim 3, comprising the simultaneous driving means for simultaneously driving the sub-pixels included in pixels apparatus.

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