JP4693436B2 - Organic EL display device - Google Patents

Description

  The present invention relates to an organic EL display device that constitutes a display using organic electroluminescence (EL). In more detail, the display image is displayed on the dark background with good contrast over the entire front surface of the display panel, and the organic structure has a structure capable of preventing the deterioration of display quality by preventing light from being lost in the display image. The present invention relates to an EL display device.

  An EL element using an organic substance has been developed as an inexpensive display element of a solid light emitting type. For example, as shown in FIG. 3, a conventional organic EL display device includes a plurality of strip-like anode electrodes 63 made of ITO or the like provided in parallel on one surface of a transparent substrate 62 such as glass. An insulating film 64 made of, for example, a positive type photoresist is formed on the band-shaped ITO film 63 where light is not emitted (will not be a pixel) by a photolithography technique, and further on the surface thereof, for example, a negative type photo A plurality of partition walls 65 are formed in parallel with the anode electrode 63 in a direction perpendicular to the anode electrode 63 by application of resist or the like and patterning. Then, the organic layer 66 is formed in a vacuum deposition apparatus, and aluminum (Al) is deposited on the surface thereof to a thickness of about 0.1 μm by the vacuum deposition apparatus, whereby the cathode electrode 67 is an anode made of ITO. It is formed in a strip shape in a direction orthogonal to the electrode 63. Since the organic layer 66 is easily deteriorated by moisture, oxygen, or the like, it is covered with a sealing member 68 such as glass or stainless steel, and a moisture absorbent 69 is provided inside. A circularly polarizing plate 60 (a combination of a linearly polarizing plate and a quarter wavelength plate) is provided on the other surface side of the transparent substrate 62.

  In this circularly polarizing plate 60, when the external light P incident from the transparent substrate 62 side is reflected by Al of the cathode electrode 67 and comes out to the display surface side, the external light is reflected in the light of the image emitted from the organic layer. This makes it difficult to see the image, and the light reflected by the metal film reverses the direction of rotation of the circularly polarized light, cancels out the light whose phases are reversed, and makes it impossible to transmit the circularly polarizing plate to darken the background. This is because the contrast ratio with the display image is increased to prevent surrounding reflections and improve display quality (for example, see Patent Document 1).

  In this configuration, a portion where the orthogonal anode electrode 63 and the cathode electrode 67 intersect becomes a pixel, a voltage is applied only to the pixel selected by both electrodes, the desired pixel is turned on, and the other surface side of the transparent substrate 62 The image is displayed by being irradiated from. In the above-described example, partition walls 65 are formed between the pixels, and Al is also deposited on the partition walls 65, so that external light is reflected by the above-described circularly polarizing plate over almost the entire display area. However, when the electrode wiring is formed at an interval of about 10 μm or less, the light leaks from between the electrodes without forming such a partition wall 65. It hardly happens.

However, for example, as shown in a schematic diagram of the front of the display panel in FIG. 4, the electrode 71 formed in the display area A is connected to one side of the transparent substrate by the wiring pattern 72 formed outside the display area A. The display data is input by being drawn out to the opposite sides. The wiring pattern 72 is formed by providing at least a metal film in order to reduce the resistance component. However, since the thickness is thin and the width is narrow, the resistance cannot be completely eliminated. On the other hand, in the organic EL display device that is current-driven when the resistance varies depending on the electrode, the brightness changes depending on the pixel, thereby degrading the display quality. Therefore, the width of the wiring pattern 72 is limited so that the resistance is almost the same for any electrode.
JP 2000-3793 A

  As described above, a metal film is used for the cathode electrode constituting the pixel, and between the pixels in the area where the image is displayed, the distance between the metal film on the partition wall or the pixel electrode is reduced in the image. There is almost no reflection of outside light, and a clear image can be displayed. However, in the actual display panel, the effective display area indicated by B in FIG. 4 is exposed on the front surface of the display panel other than the display area A where the pixels are formed. As a result, the area where the wiring pattern 72 is formed is also within the effective display area B. If external light is reflected in this area, the visual characteristics of the display image are degraded. However, since the thickness (width) of the wiring pattern 72 actually needs to be formed so that the resistance value is equal in each pixel as described above, for example, as shown by C in FIG. There are some areas where the wiring pattern spacing is wide. For this reason, there is a problem that the visual characteristics are deteriorated even when the display image itself does not include external light.

  The present invention has been made in view of such a situation, and displays a display image in a dark background with a dark background in the entire effective display area (an area exposed as a display screen including an area other than a pixel portion). An organic EL display device having a structure capable of improving display quality is provided.

An organic EL display device according to the present invention includes a translucent first substrate and a plurality of first electrodes formed on one surface of the first substrate so as to extend in a vertical direction within a display region where pixels are formed. an organic layer formed on said plurality of first electrodes, said organic layer, and a plurality of second electrodes provided in the lateral direction is a direction orthogonal to the first electrode, the display of the first substrate A plurality of first electrode wiring patterns and second electrode wiring patterns formed of a conductive film having at least a metal film on the one surface outside the region and connected to each of the plurality of first electrodes and second electrodes ; a second substrate provided so as to cover the first for the first electrode on the substrate wiring pattern and the second electrode wiring pattern and the organic layer is provided partially, on the other side of the first substrate consists of a provided circularly polarizing plate, before the first electrostatic number of Kifuku All of use wiring pattern and the second electrode wiring pattern terminals, an organic EL display device is led out to one side of the first substrate which is one end portion side of the first electrode, in front of the display panel In the effective display area exposed as a display area , at least a first dummy pattern is formed in a gap between boundaries of the plurality of first electrode wiring pattern groups and the plurality of second electrode wiring pattern groups . of the second electrode wiring pattern, the second dummy gap between the first electrode and the parallel end portion of the effective display area and the second electrode wiring pattern of the farthest position from the one side end pattern further third dummy pattern in the gap portion of the other end portion and the one side end and the opposite side of the end portion of the effective display area of the first electrode, and a second for each of the plurality of first electrode Wiring patterns for electrodes, and said plurality of first electrode and second electrode and electrically isolated have been made Rikatachi by the metal film.

  Here, the region where light transmission is conspicuous means a region where light leaks to such an extent that external light is reflected in the display screen of the display panel and deteriorates the visual recognition characteristics, and the first substrate and the second substrate. Between the first substrate and the second substrate such as one surface of the first substrate, the surface of the organic layer laminated on the first substrate, and the inner surface of the second substrate. Means the layer. Furthermore, the second substrate means a member that seals the organic layer and the like together with the first substrate, and is not limited to a plate-like body such as glass, but includes an insulating film formed by a CVD method or the like. Including meaning.

The first to third dummy patterns may be formed on one surface of the first substrate with the same material as the wiring pattern, and on the surface of the organic layer on which the second electrode is formed. It may be formed of the same material simultaneously with the formation of the two electrodes. It can also be formed on one surface of the second substrate. In this case, there is no problem even if a dummy pattern is formed in a wide range as well as a region where light transmission is conspicuous.

  With this structure, for example, when a dummy pattern is formed in the gap between the wiring patterns of the first substrate, patterning is performed so that the dummy pattern remains when the wiring pattern is formed, and etching is performed. In addition, when forming a dummy pattern on the surface of the organic layer, when forming the cathode electrode by vapor deposition or the like, similarly to the mask for vapor deposition, match the shape of the dummy pattern. By simply forming the opening, it can be easily formed without requiring any special man-hours or materials. In addition, since the metal film is formed in a portion where the external light is reflected, such as a gap in the wiring pattern, the external light is reflected by the circularly polarizing plate provided on the other surface side of the first substrate even if the external light is incident. The circularly polarized light becomes circularly polarized light, and the direction of rotation of the circularly polarized light is reversed by the reflection of the metal film and cannot be transmitted through the circularly polarizing plate. On the other hand, since the metal film is formed on the part where the wiring pattern and the cathode electrode are formed, the incident external light can be similarly transmitted through the circularly polarizing plate again with the rotation direction of the circularly polarized light reversed. become unable. As a result, even if outside light enters the entire display screen of the display panel, the light is not further reflected and returned to the viewer side of the display panel, but becomes dark, and the light emission color by the organic EL light emitting unit is within the dark color. The display screen is observed and has very good visual characteristics.

  Next, the organic EL display device of the present invention will be described with reference to the drawings. The organic EL display device of the present invention has a translucent explanatory view of one embodiment thereof and a schematic plan explanatory view of a state in which an electrode and a wiring pattern of a first substrate are formed as shown in FIG. On one surface of the first substrate 1, a plurality of first electrodes (for example, anode electrodes) 2 are formed in a vertical direction in a display area A where pixels are formed, an organic layer 3 is laminated on the anode electrode 2, and A second electrode (for example, a cathode electrode) 4 is formed on the organic layer 3 in a strip shape in a direction orthogonal to the first electrode 2, thereby forming the organic EL light emitting unit 10. And the wiring pattern 5 (5a, 5b) which has at least the metal film 51 on one surface where the first electrode 2 is formed outside the display area A of the first substrate 1 and is connected to the first electrode 2 and the second electrode 4. ) Is formed. And the 2nd board | substrate (sealing layer) 7 is provided so that the part in which the wiring pattern 5 and the organic layer 3 on the 1st board | substrate 1 were provided may be provided, and a linearly-polarizing plate is provided on the other surface side of the 1st board | substrate 1. And a circularly polarizing plate 8 made of a quarter-wave retardation plate. In the present invention, as shown in a schematic plan view of the first substrate 1 in FIG. 1 (b), the gap portion of the wiring pattern 5 exposed on the front surface of the display panel and the second electrode 4 and the wiring pattern 5 are both The wiring pattern 5, the first electrode 2, and the second electrode 4 are electrically separated in any layer between the first substrate 1 and the second substrate 7 in a region where light transmission is conspicuous without being provided. The dummy pattern 9 (9a, 9b, 9c) is formed by the metal film.

  In the example shown in FIG. 1, a dummy pattern 9 is formed on one surface of the first substrate 1 simultaneously with the formation of the wiring pattern 5. That is, the wiring pattern 5 is formed so that the terminals of the first electrode 2 and the second electrode 4 can be drawn to the end of the display panel so that a signal can be applied. In the example shown in FIG. A wiring pattern 5a for one electrode (anode electrode) is continuously formed on the lower side of the first substrate 1 with the first electrode 2, and wiring for a second electrode (cathode electrode) for connection to the second electrode 4 is provided. A pattern 5b is formed from the left and right sides of the first substrate 1 to the lower side. The first electrode 2 needs to transmit light in order to observe a display image from the other surface side of the first substrate 1, and is formed of a transparent electrode, that is, ITO, indium oxide, tin oxide, or the like. However, since the wiring pattern 5 (5a, 5b) is not a pixel, it is not necessary to transmit light, but rather it is necessary to transmit a signal with low resistance while being thinned. In the example shown in FIG. 1, after being formed simultaneously with the first electrode 2 by a transparent conductive film 52 such as ITO, a metal film 51 such as molybdenum (Mo) is further formed on the surface thereof. However, it may be formed only by the metal film 51. In addition, the part located outside the effective display area B at the end portions of the wiring patterns 5a and 5b is a terminal portion 5c connected to a wiring such as a circuit board. The metal film 51 is not provided, and only from the ITO film 52. It has become.

  The second electrode wiring pattern 5b is formed by extending the second electrode 4 to the connection region 6 when the organic layer 3 and the second electrode 4 are formed on the first electrode 2 described later. In the connection region 6 which is one end portion of the second electrode wiring pattern 5b, it is connected to the second electrode 4 and formed from the left and right side portions to the lower end portion of the first electrode 2. The terminal portions 5c of both electrodes are all aligned at the lower end portion of the first substrate 1, but it is not necessary to align them on one side of the first substrate 1, and they may be drawn out to both the upper and lower end portions. It can also be used.

  In the example shown in FIG. 1, since the terminals of all the electrodes 2 and 4 are drawn out by the wiring patterns 5a and 5b on one side of the first substrate 1, the group of the first electrode wiring pattern 5a and the second electrode A gap is formed with the group of wiring patterns 5b, the first dummy pattern 9a is formed, and the number of wiring patterns on the upper side of the second electrode wiring pattern 5b is reduced. The second dummy pattern 9b is formed in the gap. Further, in the example shown in FIG. 1, a gap is also formed on the upper side of the first substrate 1 due to the fact that all the wiring patterns 9 are drawn to the lower side of the first substrate 1. A third dummy pattern 9c is formed in the gap. That is, on one surface of the first substrate 1, the effective display area B (the area that is not covered by the frame and that faces the front of the display panel) other than the display area (the area where the pixels are formed) A substantially covers the entire area. There are only gaps of about 10 μm or less, and the other portions are covered with a metal film (wiring pattern 5 and second electrode 4).

  In the example shown in FIG. 1, the dummy patterns 9 are all formed on the first substrate 1, but the second electrode 4 is formed in the case of the third dummy pattern 9c or the second dummy pattern 9b, for example. In this case, it can be formed on the surface of the organic layer 3. Further, as will be described later, it can be formed in advance on the inner surface of the second substrate 7 or the like. In other words, it may be formed on any layer between the first substrate 1 and the second substrate 7. When it is provided on such an organic layer 3 or the second substrate 7, it is not necessary to worry about contact with the wiring pattern 5, so it can be formed in a larger pattern.

  As the transparent substrate 1, transparent substrates such as glass and various insulating plastics such as a polyimide film, a polyester film, a polyethylene film, a polyphenylene sulfide film, and a polyparaxylene film can be used. The size can be freely set according to the desired size of the display device. For example, a glass substrate of about 25 mm × 20 mm and a thickness of about 0.7 mm is used.

  The organic EL light emitting unit 10 includes a first electrode 2, an organic layer 3, and a second electrode 4. The first electrode 2 is formed, for example, by forming ITO on the entire surface by vacuum deposition or the like and then patterning it by a photolithography process. For example, about 96 strip electrodes having a width of, for example, about 150 μm are formed at intervals of about several μm to several tens of μm. An organic layer 3 is formed on the entire surface, and a metal film such as Al is formed thereon by vacuum deposition using a metal mask. About 64 second electrodes 4 are formed in a direction perpendicular to the first electrodes 2. They are formed with a width of about 150 μm at intervals of about several μm to several tens of μm. However, the interval between the cathodes (second electrodes) is preferably about 10 μm or less because the reflection of external light becomes conspicuous if the distance becomes too large.

  For example, when the first electrode 2 is an anode electrode, the organic layer 3 is formed in a structure including a hole transport layer 31, a light emitting layer 32, and an electron transport layer 33 as shown in FIG. The electron injection layer 4a is formed between the (cathode electrode) 4 and the organic layer 3 is not limited to this three-layer structure, as long as at least a light emitting layer is formed, Each layer can also be made into multiple layers. Further, when the anode and the cathode are turned upside down, the laminated structure of the organic layer 3 is also reversed.

  The hole transport layer 31 generally has a small ionization energy to improve the hole injection property to the light emitting layer 32 and improve the stable transport of holes, and confine electrons (energy) to the light emitting layer 32. And an amine-based material such as a triphenyldiamine derivative, a styrylamine derivative, an amine derivative having an aromatic condensed ring, and the like is used, and it is 10 to 100 nm, preferably 20 to 50 nm. Provided to a thickness of about. Although not shown in the figure, a hole injection layer is provided between the hole transport layer 31 and the anode electrode 3 to further improve the carrier injection property to the hole transport layer 31. . Also in this case, in order to improve the injectability of holes from the anode electrode 2, a material having good ionization energy consistency is used, and as a typical example, an amine or phthalocyanine is used. In the example shown in FIG. 2, NPB is provided as a hole transport layer 41 with a thickness of 35 nm.

  The light emitting layer 32 is selected according to the emission wavelength. For example, a DSA-based material is used as a blue material, Alq is used as a green and red light-emitting material, and the thickness is about 35 nm. Is provided. The light emitting layer 32 can obtain an emission color unique to the doping material by doping an organic fluorescent material, and can improve the light emission efficiency and stability. This doping is performed at about several weight (wt)% (0.1 to 20 wt%) with respect to the light emitting material.

  As the fluorescent substance, quinacridone, rubrene, styryl dyes and the like can be used. Alternatively, quinoline derivatives, tetraphenylbutadiene, anthracene, perylene, coronene, 12-phthaloperinone derivatives, phenylanthracene derivatives, tetraarylethene derivatives, and the like can be used. Further, it is preferably used in combination with a host material capable of emitting light by itself, and as the host material, a quinolinolato complex is preferable, an aluminum complex having 8-quinolinol or a derivative thereof as a ligand is preferable, A phenylanthracene derivative, a tetraarylethene derivative, or the like can be used.

  The electron transport layer 33 has a function of improving the injectability of electrons from the cathode electrode 4 and a function of stably transporting electrons. In the example shown in FIG. 2, Alq3 (tris (8-quinolinolato) aluminum) Is provided with a thickness of 25 nm. When this layer becomes too thick, light is emitted from this layer instead of the light emitting layer. Therefore, the layer is not made too thick, and is usually provided in a thickness of about 10 to 80 nm, preferably about 2 to 50 nm. As the electron transport layer 33, in addition to the above materials, a quinoline derivative, a metal complex having 8-quinolinol or a derivative thereof as a ligand, a phenylanthracene derivative, a tetraarylethene derivative, or the like can be used. When the gap between the electron transport layer 33 and the cathode electrode 4 is large, an electron injection layer 4a made of LiF or the like is provided similarly to the hole side.

  As the second electrode 4 serving as the cathode electrode, a metal having a small work function is mainly used in order to improve the electron injection property. As typical examples, Mg, K, Li, Na, Ca, Sr, Ba, Al, Ag, In, Sn, Zn, Zr and the like are generally used. A transparent film such as indium oxide can also be used. In order to prevent and stabilize the oxidation of these metals, alloying with other metals is often performed. In the example shown in FIG. 2, an Al layer is formed to a thickness of about 110 nm via the LiF layer 4a. Thus, the cathode electrode 4 is formed.

The 2nd board | substrate 7 protects the organic layer 3, the electrode pattern 5, etc., and can also be called a sealing member. The aforementioned dummy pattern 9 can also be formed on this second substrate. By being covered with the second substrate 7, the organic layer 3 that is weak against moisture and oxygen is protected from water vapor and oxygen in the air. As the second substrate 7, a cap pressed into a can type with stainless steel or the like may be attached to the first substrate 1, but in general, a non-metal plate such as a glass plate is used, for example, by sandblasting or the like. A counterbore hole is provided, and is attached to one surface side of the transparent substrate 1 so that the above-described organic EL light emitting unit 10 and the like are accommodated in the counterbore hole. Further, since the second substrate 7 only needs to be able to block the organic EL light emitting unit 10 from the outside air, even if it is not a cap or a glass plate, a passivation film (sealing film) such as Si _x N _{y is} formed on the entire surface. It may have a structure coated by a CVD method or the like.

  The circularly polarizing plate 8 is a linearly polarizing plate that changes light whose vibration direction is random to light only in a certain vibration direction, and is set so that the optical axis forms an angle of 45 ° with the polarizing axis of the linearly polarizing plate. The circularly polarized light reflected by the metal film is formed by pasting together a / 4 wavelength phase difference plate, and the reflected light is reversed when the polarization direction is reversed and cancels out in opposite phases. Utilizes the property that it does not return through the circularly polarizing plate.

  According to the present invention, since the dummy pattern is formed in the part where there is no gap or pixel electrode in the wiring pattern and the circularly polarizing plate is provided on the surface side, the reflection of external light is confined, and the display screen There is no reflection of external light inside. Therefore, the background is dark, and the image formed by the pixels that emit light in the organic EL section is displayed in the dark color. Only the display image is clearly displayed on the dark (black) background, and the contrast ratio is high. An organic EL display device with very high quality and excellent visual characteristics can be obtained.

It is explanatory drawing which shows one Embodiment of the organic electroluminescent display apparatus by this invention. FIG. 2 is a cross-sectional explanatory view illustrating a structural example of the organic EL light emitting unit in FIG. 1. It is a partial cross section explanatory view showing an example of the conventional organic EL display. It is plane explanatory drawing which shows the example of arrangement | positioning of the electrode and wiring pattern of an example of the conventional organic electroluminescence display.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st board | substrate 2 1st electrode 3 Organic layer 4 2nd electrode 5 Wiring pattern 6 Connection area | region 7 2nd board | substrate 8 Circularly-polarizing plate 9 Dummy pattern 10 Organic electroluminescent light emission part

Claims (3)

A first light-transmitting substrate, at one surface of the first substrate, a plurality of first electrode which is formed so as to extend longitudinally within the display region where the pixel is formed, on said plurality of first electrode An organic layer to be laminated; a plurality of second electrodes provided on the organic layer in a lateral direction orthogonal to the first electrode; and at least a metal film on the one surface outside the display area of the first substrate A plurality of first electrode wiring patterns and second electrode wiring patterns connected to each of the plurality of first electrodes and second electrodes, and the first electrode on the first substrate . consists a second substrate electrode wiring pattern and the second electrode wiring pattern and the organic layer is provided so as to cover the portion provided, the circularly polarizing plate provided on the other surface of the first substrate, for the first electrode wiring pattern and the second electrode before Kifuku number Effective display area all the line patterns terminals, an organic EL display device is led out to one side of the first substrate which is one end portion side of the first electrode, which is exposed as a display area in front of the display panel The first dummy pattern is at least a gap between the plurality of first electrode wiring pattern groups and the plurality of second electrode wiring pattern groups , out of the plurality of second electrode wiring patterns. a second dummy pattern in the gap portion between the first electrode and the parallel end portion of the effective display area and the second electrode wiring pattern of the farthest position from the one side end further the first electrode the third dummy pattern in the gap portion of the other end portion and the one side end and the opposite side of the end portion of the effective display area, each of the plurality of wiring patterns for the first electrode and the second electrode, and Serial plurality of first electrode and second electrode electrically separated to an organic EL display device in which made Rikatachi by the metal film. 2. The organic EL display device according to claim 1, wherein the first to third dummy patterns are formed on the one surface of the first substrate with the same material at the same time as the wiring pattern is formed. 2. The organic EL display device according to claim 1, wherein the first to third dummy patterns are formed of the same material on the surface of the organic layer where the second electrode is formed simultaneously with the formation of the second electrode.

Images