JP2005266077A - Display panel and its wiring method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the non-display area on a display panel. <P>SOLUTION: The display panel 40 is built by sequentially stacking anodes 12, an organic layer 36 which includes a light emitting layer of an organic EL device, and cathodes 14 on a glass substrate 28; and disposing the anode wiring 31 on the cover glass 30, then spatially connecting the anode wiring 31 and the anodes 12 with an ACF 33. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a display panel configured by arranging a plurality of light emitting elements in a matrix at each intersection of a plurality of anode lines and a plurality of cathode lines, and a wiring method for the display panel.

  As a mounting structure of a display panel configured by arranging light emitting elements in a matrix, an electrode is taken out on one side of a glass substrate and a driver IC is mounted on the glass substrate, or a driver IC is mounted on a tape. In general, a TCP (Tape Carrier Package) package is mounted on a glass substrate by ACF (Anisotropic Conductive Film). By taking out a large number of electrodes on one side of the glass substrate, the panel size can be reduced in the state after mounting, and the manufacturing process can be simplified. Patent Document 1 discloses an example of such a technique.

FIG. 6 shows a driving method of a display panel using a conventional organic EL (Electro Luminescence) element disclosed in Patent Document 2, for example. In the display panel 1, the plurality of EL elements 2 are arranged in a matrix at intersections of the plurality of anode lines 3 (1) to 3 (m, for example, 256) and the plurality of cathode lines 4 (1) to 4 (n, for example, 64). Is arranged.
Then, either the anode line 3 or the cathode line 4 (for example, the cathode line 4) is scanned so as to be sequentially connected to the ground by switching the scanning switches 5 (1) to 5 (n) at a constant period, and the scanning period. In synchronism with this, the other (for example, anode line 3) drive switches 6 (1) to 6 (m) are switched and sequentially connected to the current sources 7 (1) to 7 (n), so that EL elements at arbitrary intersection positions 2 is made to emit light. The scan switches 5 (1) to 5 (n) are configured as a scan driver IC 9, and the drive switches 6 (1) to 6 (m) and the current sources 7 (1) to 7 (m) are signal drivers. It is configured as IC8.

  For example, when the EL element 2 (1, 1) and the EL element 2 (1, 2) are caused to emit light, the scanning switch 5 (1) is switched to the ground side as shown in FIG. 1) is set to the ground potential, the drive switches 6 (1) and 6 (2) are switched to the current sources 7 (1) and 7 (2), and the drive switches 6 (3) to 6 (256) are switched. Switch to the ground side. Then, a drive current is supplied only to the EL elements 2 (1, 1) and 2 (1, 2) to emit light.

  Such switching of the scanning switch 5 and the driving switch 6 is repeated at high speed so that the EL element 2 at an arbitrary position emits light, and the human eye can visually recognize that a plurality of EL elements 2 emit light simultaneously. Image data is displayed on the display panel 1. Further, by applying a reverse bias voltage Vcc having the same potential as the power supply voltage to the non-selected cathode lines 4 (2) to 4 (64), the other EL elements 2 are prevented from erroneously emitting light.

  FIG. 7 shows a mounting structure substantially similar to the display panel disclosed in Patent Document 2. On the glass substrate 11, a plurality of anodes 12 are formed in the vertical direction in FIG. 7A, and an organic material is sealed thereon to form a light emitting layer 13. The anode 12 is made of a transparent material such as ITO (Indium Tin Oxide). A plurality of cathodes 14 are formed on the light emitting layer 13 in the left-right direction in FIG. The cathode 14 is formed of a material such as Al (aluminum). An organic EL element is formed at the intersection of the anode 12 and the cathode 14.

Below the glass substrate 11, a TCP having a driver IC 16 mounted on a tape 15 is ACF-connected. Here, the driver IC 16 is obtained by integrating the scanning driver IC 9 and the signal driver IC 8. The driver IC 16 and the anode 12 are connected by extending the wiring electrode portion 17 made of ITO to one side (tape 15 side) of the glass substrate 11. On the other hand, the driver IC 16 and the cathode 14 are connected by separately forming a wiring electrode 18 made of ITO, and the wiring electrode 18 and one of the left and right ends of the cathode 14 are alternately connected to the odd number and even number. And it is drawn around to one side of the glass substrate 11.
JP-A-6-11721 JP-A-11-311978

  When such a mounting configuration is employed, a portion corresponding to a so-called “frame” around the area of the region where screen display is performed using the organic EL element as a pixel by extending the wiring electrode 18 on the cathode 14 side long. The area of will become large. For example, when there are 64 cathodes 14 and the wiring pitch is 0.1 mm, a frame with a width of 6.4 mm occupies the outside of the display area. In particular, in the case of using a current-driven pixel such as an organic EL element, it is necessary to design the wiring resistance to be smaller than that of, for example, a liquid crystal display panel. It must be large.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a display panel and a display panel wiring method capable of reducing the area occupied by the non-display region.

  According to the display panel of claim 1, the anode line, the light emitting layer of the light emitting element, and the cathode line are sequentially laminated on the first substrate, and at least one of the cathode side wiring and the anode side wiring is formed on the second substrate of the upper layer. Place one. Then, at least a part of the wiring on the second substrate side is arranged so as to pass through a portion corresponding to the display region constituted by the arrangement of the plurality of light emitting elements, and the wiring and the electrode on the second substrate side are arranged in a space. Wiring connection. Here, the “electrode” means a cathode, an anode, or both. If comprised in this way, the freedom degree of wiring will improve by performing wiring using a 2nd board | substrate. Accordingly, since the amount of wiring arranged on the first substrate side can be reduced, the area of the non-display area can be reduced and the entire display panel can be made smaller.

  According to the display panel of claim 2, since the laminated body composed of the anode line, the light emitting layer of the light emitting element, and the cathode line laminated on the first substrate is covered with the insulating protective film, the laminated body, the second substrate, It is no longer necessary to provide a space for ensuring insulation between the display panels, and the display panel can be made thinner.

  According to the display panel of the third aspect, since the concave portion is formed on the side where the wiring of the second substrate is arranged, the first, first, and the like without using an insulating protective film as in the second aspect. Insulation between the second substrates can be achieved, and the display panel can be configured to be thin.

  According to the display panel of the fourth aspect, both ends of the cathode line are short-circuited using the wiring electrodes arranged on the second substrate. If comprised in this way, the wiring resistance by the side of a cathode line can be reduced and generation | occurrence | production of brightness irregularity can further be suppressed.

(First embodiment)
Hereinafter, a first embodiment in which the present invention is applied to a display panel configured with organic EL elements as pixels will be described with reference to FIG. The same parts as those in FIGS. 6 and 7 are denoted by the same reference numerals and description thereof is omitted, and only different parts are described below. In the first embodiment, a tape 32 on which a driver IC (anode side drive unit, cathode side drive unit) 16 is mounted on a glass substrate (first substrate) 28 instead of the glass substrate 11 is provided on the left side in FIG. Is arranged. A cathode-side wiring 23 (made of ITO) for connecting the cathode (cathode line) 14 and the terminal of the driver IC 16 is linearly arranged so as to be continuous in the wiring direction of the cathode 14, and the driver IC 16 It is connected with the terminal of the shortest distance.

An insulating protective film 29 is formed so as to cover the cathode 14. An anode side wiring 31 is formed and arranged on the side of the cover glass (second substrate) 30 facing the protective film 29, and the anode 12 and the anode are formed on the glass substrate 28 side in the same manner as in FIG. Electrical connection with the side wiring 34 is made through the ACF 33.
As a result, the other ends of all the cathode side wirings 23 and the anode side wirings 34 are located on the left side of the glass substrate 28, and are connected to the wirings on the tape 32 side via the ACF 33. In the above description, the display panel 40 is configured by removing the driver IC 16 and the tape 32. Note that the driving method of the display panel 40 is not different from the known technology.

FIG. 2 shows a process for producing a display panel. First, the anode 12, the cathode side wiring 23, and the anode side wiring 34 are formed on the glass substrate 28 by using a transparent electrode film such as ITO using a sputtering method, a photolithography method, or the like (see FIG. 2A). . The anode 12 is patterned in a stripe shape extending in the vertical direction of the glass substrate 28. As shown in the plan view of FIG. 2A, the cathode side wiring 23 is arranged on the left end side of the glass substrate 28 in accordance with the position of the cathode 14 to be formed later, and the cathode side wiring 23 is sandwiched therebetween. Anode-side wiring 34 is arranged above and below.
Further, on the upper end side and the lower end side of the cover glass 30, anode side wirings 31 for connecting the anode 12 on the glass substrate 28 side and the anode side wirings 34 are formed of a transparent electrode film such as ITO (FIG. 2 (b)).

  Next, after filling the insulating material 25 between the anode side wirings 31 on the glass substrate 28 side, the organic layer 36 is formed by vapor deposition (see FIG. 2C). The organic layer 36 is, for example, formed by sequentially forming a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, an electron injection layer, and the like from the anode side, and the light emitting layer contains a fluorescent dye. In the light emitting layer, light is emitted by energy generated when electrons and holes are recombined.

Subsequently, the cathode 14 is formed of a metal such as aluminum on the organic layer 36 by vapor deposition or laser patterning (see FIG. 2D). In this case, the cathode 14 is patterned in a stripe shape extending in a direction orthogonal to the anode 12. Then, an organic EL element is formed at the intersection of the cathode 14 and the anode 12.
Then, a laminate 37 composed of the anode 12, the organic layer 36, and the cathode 14 on the glass substrate 28 is covered with a protective film 29 (see FIG. 2E). The protective film 29 is formed by, for example, an ALE (Atomic Layer Epitaxicy) method using H ₂ O as a film forming material. For example, H ₂ O and TMA (tetramethylaluminum) are used as raw materials, and the protective film 29 made of Al ₂ O ₃ is formed. That is, by alternately supplying H ₂ O and TMA into the film forming chamber, an Al ₂ O ₃ film is grown by a reaction between the _two . The film formation conditions are, for example, a film formation temperature of 100 degrees,
TMA: 1 second introduction → N2 purge → H ₂ O: 1 second introduction → N2 purge →
By repeating 5000 for one cycle, the thickness of the protective film 29 becomes about 250 nm.

  Next, the cover glass 30 is overlapped on the glass substrate 28 side and spatially connected by the ACF 39. At this time, the anode 12 and the anode side wiring 31, and the anode side wiring 31 and the anode side wiring 34 are also electrically connected by the ACF 39 (see FIG. 2F). The above constitutes the display panel 40. Finally, the cathode side wiring 23 and the anode side wiring 31 on the glass substrate 28 are connected to the wiring on the tape 32 and the anode side wiring 34 by using the ACF 33 to rearrange the electrodes.

  As described above, according to the present embodiment, the anode 12, the organic layer 36 including the light emitting layer of the organic EL element, and the cathode 14 are sequentially laminated on the glass substrate 28, and the anode-side wiring 31 is disposed on the cover glass 30. The anode-side wiring 31 and the anode 12 were spatially connected by the ACF 33. That is, by using the cover glass 30, the degree of freedom of wiring is improved, and the amount of wiring arranged on the glass substrate 28 side can be reduced.

  Since at least a part of the anode-side wiring 31 on the cover glass 30 side is arranged so as to pass through a portion corresponding to the display area in which the organic EL elements as pixels in the display panel 40 are arranged in a matrix, display The portion outside the region, that is, the portion corresponding to the “frame” in the so-called painting is reduced, and the entire display panel 40 can be made smaller. By further reducing the area of the non-display area, the entire display panel can be further reduced in size. In addition, since the wiring resistance of the cathode-side wiring 23 is reduced, it is possible to reduce the light emission luminance and the luminance unevenness of the display panel 40 as compared with the conventional case.

  Further, since the laminated body 37 composed of the anode 12, the organic layer 36, and the cathode 14 laminated on the glass substrate 28 is covered with the insulating protective film 29, the laminated body 37 and the anode-side wiring 31 on the cover glass 30 side, It is no longer necessary to provide a space for securing insulation between the display panel 40 and the display panel 40 can be made thinner.

(Second embodiment)
FIG. 3 shows a second embodiment of the present invention. The description of the same parts as in the first embodiment is omitted, and only different parts will be described below. The basic configuration of the second embodiment is the same as that of the second embodiment. However, in the second embodiment, the cathode 14 is connected to the cathode-side wiring 23 in the first embodiment on the side opposite to the left end. The right end is also configured to connect with the wiring on the tape 32.

That is, the cover glass 30 is formed with a cathode-side wiring 41 for connecting the right end portion of the cathode 14 and the wiring on the tape 32, and the two are connected by ACF (not shown). Other configurations are the same as those of the first embodiment, and the above constitutes the display panel 42.
As described above, according to the second embodiment, since both ends of the cathode 14 are short-circuited using the cathode-side wiring 41 arranged on the cover glass 30, the wiring resistance on the cathode line 14 side is equivalently reduced. As a result, the occurrence of uneven brightness in the display panel 42 can be further suppressed.

(Third embodiment)
FIG. 4 shows a third embodiment of the present invention, and only the parts different from the first embodiment will be described. In the configuration of the third embodiment, the protective film 29 covering the stacked body 37 is removed from the display panel 40 of the first embodiment. Instead of the cover glass 30, a cover glass (second substrate) 43 having a recess 43 a formed on the side where the anode-side wiring 31 is disposed is used. That is, the cover glass 43 is a so-called dug glass, and the anode side wiring 31 is disposed inside the recess 43a. And the cover glass 43 and the glass substrate 28 side are connected by ACF44. Other configurations are the same as those of the first embodiment, and the above constitutes the display panel 44.

  As described above, according to the third embodiment, since the recess 43a is formed on the side of the cover glass 43 on which the anode side wiring 31 is disposed, the glass without using the protective film 29 as in the second embodiment. Insulation between the wiring on the substrate 28 side and the wiring on the cover glass 43 side can be achieved, and the display panel 44 can be made thin.

(Fourth embodiment)
FIG. 5 shows a fourth embodiment of the present invention. The configuration of the fourth embodiment is similar to the configuration shown in FIG. 7, in which a TCP on which the tape 46 and the driver IC 16 are mounted is arranged on the lower side of the glass substrate (first substrate) 45 in FIG. ACF connected. The driver IC 16 and the anode 12 are connected by extending the anode-side wiring 47 made of ITO to the lower side of the glass substrate 45 as in FIG. However, the anode-side wiring 47 is arranged so that the wiring from the center toward the left and right sides is gradually bent toward the center so that the wiring pitch is narrower than that of the anode 12.

  On the other hand, for the connection between the driver IC 16 and the cathode 14, a cathode side wiring 48 made of ITO is formed on the cover glass (second substrate) 49 side, and one end of either the left side or the right side of the cathode side wiring 48 and the cathode 14 is formed. Are alternately connected in odd-numbered and even-numbered ones, and are routed to the lower side of the glass substrate 45. Other configurations are the same as those in the first embodiment, and the above constitutes the display panel 50. In the case of the fourth embodiment configured as described above, the same effect as that of the first embodiment can be obtained.

The present invention is not limited to the embodiments described above and illustrated in the drawings, and the following modifications or expansions are possible.
The element constituting the pixel is not limited to the organic EL element, and may be any element that emits light by current driving.
The material of the substrate is not limited to glass, and a material having transparency at least on the side where light emission display is performed may be used.
In the first embodiment, the cathode side wiring may be arranged on the cover glass 30 side.
You may implement combining 2nd Example and 3rd Example.

It is 1st Example at the time of applying this invention to the display panel comprised as an organic EL element as a pixel, (a) is the figure which looked at the display panel from the glass substrate side, (b) is (a). The figure which shows an AA 'cross section typically, (c) is a figure which shows the BB' cross section of (a) typically. The figure which shows the creation process of the display panel FIG. 1 equivalent view showing a second embodiment of the present invention. FIG. 1 equivalent view showing a third embodiment of the present invention. FIGS. 1A and 1B are diagrams showing a fourth embodiment of the present invention. Electrical configuration diagram explaining the driving method of a display panel of the prior art 1 (a), (b) equivalent diagram

Explanation of symbols

  In the drawing, 14 is an anode, 14 is a cathode, 16 is a driver IC, 28 is a glass substrate (first substrate), 29 is a protective film, 30 is a cover glass (second substrate), 31 and 34 are anode side wirings, 36 Is an organic layer (light emitting layer), 37 is a laminate, 40 is a display panel, 41 is a cathode side wiring, 42 is a display panel, 43 is a cover glass (second substrate), 43a is a recess, 44 is a display panel, 45 is A glass substrate (first substrate), 47 is an anode side wiring, 48 is a cathode side wiring, 49 is a cover glass (second substrate), and 50 is a display panel.

Claims (8)

A plurality of light emitting elements are arranged in a matrix at each intersection of a plurality of anode lines and a plurality of cathode lines, and the light emitting elements are connected to the plurality of anode lines and cathode lines by an anode side driving unit and a cathode side driving unit. In a display panel that emits light by being driven by current via
The anode line, the light emitting layer of the light emitting element, and the cathode line are sequentially laminated on the first substrate, and the second substrate is disposed on the upper layer.
At least a cathode side wiring for connecting the plurality of cathode lines and the cathode side driving unit to the second substrate, and an anode side wiring for connecting the plurality of anode lines and the anode side driving unit. Arranging either one and arranging at least a part of the wiring on the second substrate side so as to pass through a portion corresponding to a display region constituted by the arrangement of the plurality of light emitting elements,
A display panel comprising: wiring on the second substrate side and electrodes spatially connected by wiring.   The display panel according to claim 1, wherein a laminate including the anode line, the light emitting layer of the light emitting element, and the cathode line laminated on the first substrate is covered with an insulating protective film. .   The display panel according to claim 1, wherein the second substrate has a recess formed on a side where the wiring is disposed.   4. The display panel according to claim 1, wherein both ends of the cathode line are short-circuited using wiring electrodes arranged on the second substrate. 5. A plurality of light emitting elements are arranged in a matrix at each intersection of a plurality of anode lines and a plurality of cathode lines, and the light emitting elements are connected to the plurality of anode lines and cathode lines by an anode side driving unit and a cathode side driving unit. In a wiring method of a display panel that emits light by being driven by a current via
On the first substrate, the anode line, the light emitting layer of the light emitting element, and the cathode line are sequentially laminated,
A second substrate is disposed on the cathode line;
At least a cathode side wiring for connecting the plurality of cathode lines and the cathode side driving unit to the second substrate, and an anode side wiring for connecting the plurality of anode lines and the anode side driving unit. Arranging either one and arranging at least a part of the wiring on the second substrate side so as to pass through a part corresponding to a display region constituted by the arrangement of the plurality of light emitting elements,
A wiring method of a display panel, wherein the wiring on the second substrate side and the electrode are spatially connected by wiring.   A laminate including the anode line, the light emitting layer of the light emitting element, and the cathode line laminated on the first substrate is covered with an insulating protective film before the second substrate is disposed. The display panel wiring method according to claim 5.   7. The display panel wiring method according to claim 5, wherein the second substrate has a recess formed on a side where the wiring is arranged. 8. The display panel wiring method according to claim 5, wherein both ends of the cathode line are short-circuited using wiring electrodes disposed on the second substrate.

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