JP3713463B2 - EL display device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an EL display device including a light emitting layer made of a thin film of an EL (electroluminescence) material, particularly an organic EL material.
[0002]
[Prior art]
Organic EL displays have been put into practical use in part as self-luminous displays capable of high quality display and thinning instead of liquid crystal displays. This is because the use of an organic compound that can be expected to have good light-emitting characteristics for the light-emitting layer used in the EL display has led to an increase in efficiency and longevity that can withstand practical use.
[0003]
The organic EL display described above has a configuration in which a plurality of first electrode lines and a plurality of second electrode lines are stacked on a substrate so as to intersect (orthogonal) each other with an organic EL light emitting layer interposed therebetween. ing. As the first electrode line, a transparent first electrode line made of ITO (indium tin oxide), which is also a light transmissive material, is generally formed on a light transmissive substrate such as glass. Is used to pattern the stripe pattern.
[0004]
Then, a plurality of electrically insulating partition walls whose cross-sectional shape is substantially inverted isosceles trapezoidal shape is formed in a direction intersecting with the first electrode line, and an organic EL material layer is formed between the partition walls. To do. Further, on the organic EL material layer between the partition walls, for example, a metal second electrode line mainly composed of an aluminum material is formed. In this case, generally, the first electrode line constitutes an anode line, and the second electrode line constitutes a cathode line.
[0005]
In the EL display device having the above-described configuration, a plurality of electrically insulating partition walls are formed in advance so that an organic EL material is vapor-deposited thereon and further a second electrode line is formed. By sequentially depositing the material using, for example, resistance heating vapor deposition, the second electrode line as the cathode line is electrically separated through the protruding partition wall, and is formed in a stripe shape between the partition walls. . Therefore, the partition is also called a cathode partition.
[0006]
[Problems to be solved by the invention]
By the way, since the ITO constituting the first electrode line has a higher specific resistance than the second electrode line mainly composed of an aluminum material, for example, it is made of an organic EL material formed in the extending direction of the first electrode line. There arises a problem that the brightness of the light emitting pixels is uneven. Therefore, as means for solving such a problem, ITO constituting each first electrode line is divided into two at the substantially central portion of the glass substrate, and the outer ends of each divided first electrode line, that is, glass. It can be considered that the drive signals from the drive circuit are supplied to the first electrode lines at both ends of the substrate.
[0007]
FIG. 4 schematically shows such a state, and in the right end portion of the light emitting display panel, in particular, the central portion is enlarged, and the range from the central portion to the upper and lower end portions is omitted. In FIG. 4, reference numeral 1 denotes a light transmissive glass substrate, for example, and the first electrode lines 2 a 1 to 2 an and 2 b 1 to 2 bn made of ITO are formed on the glass substrate 1 so as to be parallel to each other. . The first electrode lines have a first group of electrode lines 2a1 to 2an and a second group of electrode lines 2b1 to 2bn with a substantially central part of the glass substrate 1 (a central part in the vertical direction in the figure) as a boundary. Each electrode line of the first group and each electrode line of the second group are isolated so as to face each other in the center and are electrically insulated.
[0008]
On the other hand, the cathode partition walls 4 are formed on the glass substrate 1 in parallel with each other so as to be orthogonal to the first electrode lines made of ITO through an insulating layer as will be described later. Then, in the state where the cathode partition 4 is formed, the organic EL material layer is formed by, for example, resistance heating evaporation, and the aluminum alloy layer is also formed by resistance heating evaporation. As a result, the organic EL material layer and the aluminum alloy layer are formed between the cathode barrier ribs 4 in a state where they are separated and electrically insulated by the cathode barrier ribs 4. The aluminum alloy layer formed between the cathode partition walls 4 constitutes the second electrode line 6.
[0009]
That is, the first electrode line and the second electrode line described above are formed on the glass substrate 1 so as to be orthogonal to each other, and are formed at the intersections between the first electrode line and the second electrode line. The organic EL material layer constitutes the light emitting pixel 7.
[0010]
And with respect to each electrode line 2a1-2an of the said 1st group which comprises a 1st electrode line, in the upper end part of the glass substrate 1, the extraction pad part 8a1-8an is each vapor-deposited, and this extraction pad part 8a1- An FPC (flexible circuit board) (not shown) is electrically connected to 8an by means such as thermocompression bonding. Similarly, lead pad portions 8b1 to 8bn are vapor-deposited at the lower end portion of the glass substrate 1 with respect to the second group of electrode wires 2b1 to 2bn constituting the first electrode wire, respectively. An FPC (not shown) is electrically connected to 8b1 to 8bn by the same means.
[0011]
Similarly, a drawing pad portion 9 is deposited on the second electrode line at the right end of the glass substrate 1 in FIG. 4, and an FPC (not shown) is electrically connected to each drawing pad portion 9 by the same means. Connected to.
[0012]
Then, a drive signal from a first anode drive circuit (not shown) is given through the FPC connected to each electrode line of the first group constituting the first electrode line, and each electrode line of the second group A drive signal from a second anode drive circuit (not shown) is given through the FPC connected to the. Further, a drive signal from a cathode drive circuit (not shown) is given through the FPC connected to the second electrode line.
[0013]
According to the configuration of the display panel shown in FIG. 4, the first group of electrode lines 2a1 to 2an and the second group of electrode lines 2b1 that constitute the first electrode lines at the substantially central portion of the substrate 1 in the vertical direction. ˜2bn is bisected at the substantially central portion of the glass substrate 1, and the anode drive signal is supplied from the outer ends thereof, so that the substantial length of the first electrode line can be halved. . Therefore, the influence of the specific resistance in the first electrode line formed of ITO can be reduced.
[0014]
By the way, in the display panel shown in FIG. 4 described above, the electrode lines of the first group and the electrode lines of the second group facing each other must be electrically insulated. Then, in order to form the second electrode lines, the cathode barrier ribs are formed at the facing portions of the first group electrode lines and the second group electrode lines, and the cathode barrier ribs are formed in parallel to the cathode barrier ribs. Are formed so as to be orthogonal to the first electrode line.
[0015]
Here, the facing portions of the first group of electrode lines 2a1 to 2an and the second group of electrode lines 2b1 to 2bn need to have a predetermined interval in order to ensure electrical insulation between them. In addition, the gap value A of the light emitting pixels 7 formed at the facing portions of the electrode lines of the first group and the second group must be relatively large as a result of the formation of the cathode barriers therebetween. I don't get it.
[0016]
On the other hand, the interval between the cathode partition walls 4 can be made relatively narrow, and accordingly, the light emission formed at portions other than the facing portions of the electrode lines of the first group and the second group. As a result, the gap value B of the pixel 7 can be made narrower than the gap value A.
[0017]
Therefore, the gap value A of the light-emitting pixel 7 is larger than the others in the facing portion between the first group and each electrode line of the second group. In the form shown in FIG. This causes a sense of incongruity as if a non-lighting region is formed in the left-right direction, and has the problem of reducing the commercial value.
[0018]
The present invention has been made paying attention to the technical problems described above, and has been described above even when the first electrode lines are configured to face each other separately in the first group and the second group. Thus, it is an object of the present invention to provide an EL display device capable of preventing a sense of incongruity as if a non-lighting region was formed at the facing portions.
[0019]
[Means for Solving the Problems]
The EL display device according to the present invention made to achieve the above object includes a plurality of first electrode lines arranged on a substrate and formed in a stripe shape, and a plurality extending in a direction intersecting the first electrode lines. An EL display device comprising: a second electrode line; and an EL material layer formed between the first electrode line and the second electrode line to form a light-emitting pixel, wherein the first electrode line is The electrode lines of the first group and the second group are formed so as to face each other at a predetermined position of the substrate, and the electrode lines of the first group and the second group are formed from the facing parts. Thus, the gap value between the light emitting pixels formed toward both outer sides is characterized in that it is configured to decrease stepwise.
[0020]
In this case, a plurality of partition walls preferably extending in a direction intersecting with the first electrode lines and protruding on the substrate are provided, and at least the EL material layer and the second electrode lines are provided between the partition walls. A film is formed.
[0021]
In a preferred embodiment, the size of the light emitting pixels formed from the facing portion along the electrode lines of the first group and the second group toward both outer sides is substantially the same, and the light emission is performed. As the gap value between the pixels decreases, the pitch between the light emitting pixels is changed.
[0022]
In another preferred embodiment, the pitch between the light emitting pixels formed toward the outer sides along the electrode lines of the first group and the second group from the facing portion is substantially the same, and The gap value is configured to decrease stepwise.
[0023]
Furthermore, the substrate and the first electrode line are preferably made of a light-transmitting material, and the EL material layer contains an organic compound material.
[0024]
According to the EL display device having the above-described configuration, the first electrode line is divided into two at a predetermined portion of the substrate on which the film is formed, for example, at substantially the center of the substrate, and the first group electrode line and the second group electrode line face each other. Formed into a state. For this reason, as described above, the gap value between the light emitting pixels must be formed to be large to some extent in the facing portion between the electrode lines of the first group and the second group.
[0025]
However, as described above, the gap value between the light emitting pixels formed toward the outer sides along the electrode lines of the first group and the second group from the facing portion is decreased in a stepwise manner. It is possible to prevent an uncomfortable feeling as if a non-lighting region was formed at the facing portion.
[0026]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an EL display device according to the present invention will be described based on an embodiment shown in the drawings. First, an example of a manufacturing process of this type of display panel will be described based on FIGS. 1 is a cross-sectional view showing a state in which the display panel is cut in a direction perpendicular to the cathode barrier rib, and FIG. 2 is a perspective view showing a part of the display panel in a state where the cathode barrier rib is formed. Yes.
[0027]
First, as shown in FIG. 1A, first electrode lines 2 are formed in a stripe shape on a transparent glass substrate 1. The first electrode line 2 is made of ITO as a transparent material having a relatively high work function, and is patterned by using a general photolithography method. Then, for example, by spin-coating polymer polyimide so as to have a predetermined film pressure, exposure and development, the insulating layer 3 is formed in a matrix as shown in FIG.
[0028]
Subsequently, the cathode barrier 4 is formed on the insulating layer 3. Here, a lift-off negative photoresist whose UV light transmission is intentionally lowered is spin-coated and prebaked. And it exposes by irradiating UV light through the hard chrome mask provided with the light transmission slit. At this time, since the above-described photoresist has a low transmittance of UV light, a difference in solubility in a developing solution occurs in the depth direction.
[0029]
Therefore, the cathode partition 4 having the overhang portion 4a is formed to protrude from the substrate 1 as shown in FIGS. 1B and 2 due to the difference in developability by spray showering the alkali developer on the substrate. Thereby, the cross-sectional shape orthogonal to the longitudinal direction in each cathode partition 4 is made into the structure which formed the substantially reverse isosceles trapezoid.
[0030]
In this way, when the second electrode line (cathode line), which will be described later, is formed by forming a structure in which the cross-sectional shape orthogonal to the longitudinal direction of each cathode partition 4 is substantially inverted isosceles trapezoid, the cathode partition 4 As a result, the adjacent cathode lines are separated, and sufficient electrical insulation can be ensured.
[0031]
Subsequently, after the above-described cathode barrier ribs are formed, the organic EL material layer 5 is formed by, for example, resistance heating vapor deposition as shown in FIG. In this case, the organic EL material layer 5 is formed between the partition walls 4 and is also formed on the upper portion of the partition walls 4 as indicated by reference numeral 5 ′. Further, as shown in FIG. 1D, the aluminum alloy layer 6 is formed by, for example, resistance heating vapor deposition.
[0032]
In this case, the aluminum alloy layer 6 is formed on the organic EL material layer 5 formed between the partition walls 4 and the organic EL material layer 5 ′ formed on the partition walls 4. A film is also formed as indicated by reference numeral 6 'above. However, the layers 5 'and 6' formed on the partition 4 do not contribute to the light emitting action as the display panel.
[0033]
By forming the aluminum alloy layer 6 as described above, the second electrode lines 6 are formed separately from each other in the region sandwiched between the cathode partition walls 4, which become the striped cathode lines. The organic EL material layer 5 has a configuration in which light emitting pixels 7 are arranged in a matrix between a first electrode line (anode line) 2 and a second electrode line (cathode line) 6 that intersect each other. That is, the light emitting pixels 7 are arranged in the openings in the insulating layer 3 formed in a matrix when viewed through the glass substrate 1 in FIGS.
[0034]
Finally, using the vapor deposition mask, as shown in FIG. 4, the first group of electrode lines 2a1 to 2an and the second group of electrode lines 2b1 to 2bn constituting the first electrode line (anode line). In contrast, drawer pad portions 8a1 to 8an and 8b1 to 8bn are formed, respectively. Further, a lead pad portion 9 is also formed for each second electrode line (cathode line) 6 by the same means.
[0035]
FIG. 3 shows a main part of the display panel showing the characteristic points of the EL display device according to the present invention, wherein the first and second group electrode lines constituting the first electrode line face each other. The portion arranged in the state and the vicinity of the end portion of the second group of electrode lines are shown enlarged while omitting the middle of the portion. In FIG. 3, parts corresponding to the parts already described are denoted by the same reference numerals.
[0036]
The basic configuration of the display panel shown in FIG. 3 is substantially the same as that shown in FIG. That is, the first group of electrode lines 2a1 to 2an constituting the first electrode line and the second group of electrode lines 2b1 to 2bn are opposed to each other. The gap value between the light emitting pixels 7 formed in the facing portion is set to A for the reason described above. On the other hand, the gap value between the light emitting pixels 7 formed along the other first electrode lines can be B as described above.
[0037]
Therefore, in the embodiment shown in FIG. 3, the gap value between the light-emitting pixels 7 formed from the facing portion to the outer sides along the electrode lines of the first group and the second group is the cap. It is formed so as to decrease stepwise from the value A toward the gap value B.
[0038]
That is, in the embodiment shown in FIG. 3, the gap value between the light emitting pixels 7 formed in the facing portion is set to A as described above, and the gap value between the adjacent light emitting pixels 7 is set to C1. The Further, the gap value between the adjacent light emitting pixels 7 is set to C2. Similarly, the gap value between the respective light emitting pixels 7 is set to C3, C4... Cn in order, and finally the gap value is set to B. That is, A>C1>C2>...>Cn> B.
[0039]
In this case, the plurality of light emitting pixels along the first electrode line may be configured as one unit with the same gap value, and the gap value may be decreased stepwise between the units. That is, A ≧ C1 ≧ C2... Cn ≧ B may be satisfied. In addition, the gap value may be configured to decrease stepwise from A to B along the first group and the second group of electrode lines, for example, until reaching an intermediate point. That is, in this case, the gap values between the light emitting pixels 7 from the intermediate point to both outer sides are all set to B.
[0040]
By configuring as described above, the gap value A between the light emitting pixels 7 formed in the facing portion decreases stepwise toward both outer sides of the first electrode line, and the gap value reaches B. Therefore, it is possible to prevent the display panel from giving a sense of incongruity as if a non-lighting region was formed, for example, at the central portion.
[0041]
In the embodiment shown in FIG. 3, the sizes of the light emitting pixels 7 formed toward both outer sides along the electrode lines of the first group and the second group are substantially the same, and the light emission is performed. As the gap value between the pixels 7 decreases, the pitches P1, P2, P3P,... Between the light emitting pixels are configured to decrease stepwise. However, the pitches P1, P2, P3P... Between the light emitting pixels 7 formed outwardly along the electrode lines of the first group and the second group are substantially the same, and the gap values A, Even if C1, C2,... B are configured to decrease stepwise, the same effect as described above can be obtained.
[0042]
【The invention's effect】
As is apparent from the above description, according to the EL display device of the present invention, the first electrode line is divided into two at the central portion of the substrate, for example, to form the first group and the second group of electrode lines. Since the gap value between the light emitting pixels formed toward the outer sides from the facing portions of the electrode lines of the first group and the second group is decreased stepwise, it is as if the central portion of the display panel It is possible to prevent an uncomfortable feeling that a non-lighting region is formed.
[Brief description of the drawings]
FIG. 1 is a stacked structure diagram illustrating an example of a manufacturing process of an EL display device.
2 is a perspective view showing a state of a substrate structure in the middle of the manufacturing process shown in FIG. 1. FIG.
FIG. 3 is a block diagram showing a main part of a display panel showing the characteristic points of an EL display device according to the present invention.
FIG. 4 is a configuration diagram showing a main part of a display panel in which a first electrode line is divided into two at a substantially central portion of a substrate.
[Explanation of symbols]
1 Substrate 2a1-2an First electrode line (anode line)
3 Insulating layer 4 Cathode partition 4a Overhang part 5 Organic EL material layer 6 Second electrode line (cathode line)
7 Light emitting pixels 8a1 to 8an Drawer pad part 9 Drawer pad part

Claims (6)

A plurality of first electrode lines arranged on a substrate in a stripe shape, a plurality of second electrode lines extending in a direction intersecting the first electrode lines, and the first electrode lines and the second electrode lines An EL display device comprising an EL material layer formed between them and forming a light emitting pixel,
The first electrode lines are bisected at predetermined positions of the substrate so that the electrode lines of the first group and the second group are formed in a face-to-face state, and the first group and the second group are formed from the facing part. An EL display device, characterized in that a gap value between light emitting pixels formed toward both outer sides along each electrode line is reduced stepwise. A plurality of partition walls extending in a direction intersecting with each first electrode line and protruding on the substrate are provided, and at least the EL material layer and the second electrode line are formed between the partition walls. The EL display device according to claim 1. The sizes of the light emitting pixels formed toward the outer sides along the electrode lines of the first group and the second group from the facing portion are made substantially the same, and as the gap value between the light emitting pixels decreases. The EL display device according to claim 1, wherein the EL display device is configured to change a pitch between the light emitting pixels. The pitch between the light emitting pixels formed toward the outer sides along the electrode lines of the first group and the second group from the facing portion is made substantially the same, and the gap value between the light emitting pixels decreases stepwise. The EL display device according to claim 1 or 2, wherein the EL display device is configured as described above. The EL display device according to claim 1, wherein the substrate and the first electrode line are made of a light-transmitting material. The EL display device according to claim 1, wherein the EL material layer includes an organic compound material.

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