JP2006032058A - Light emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light emitting device having an enhanced capability of preventing intrusion of water or the like by employing anode bonding to seal a glass substrate for incorporating an organic light emitting element and a protecting plate, thereby solving the problem that, while the development of a light emitting device using an organic EL element has been pursued, it has been difficult to prevent the intrusion of gas, water or the like because a UV-type adhesive has been used for sealing the glass substrate and the protecting plate. <P>SOLUTION: First and second electrode layers 13, 15 sandwiching an organic light emitting layer 14 therebetween are provided on the surface of a transparent glass substrate 11, and they are covered with a protecting plate 17, with a bonding metal layer 16 interposed between the protecting plate 17 and the glass substrate 11. The metal layer 16 is subjected to anode bonding to the glass substrate 11 and the protecting plate 17. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a light emitting device using an organic electroluminescence element, and more particularly to a light emitting device in which an organic electroluminescence layer is reliably sealed with a glass substrate and a protective plate.

  Conventionally, a large display screen with a large number of light bulbs arranged in a flat shape is used to display image data that informs a large number of spectators about the players participating, odds, scores, etc. in a wide area such as a racetrack or baseball field Has been. In addition to such a large display screen, a liquid crystal display device has recently been frequently used in place of a light bulb display on a display screen for notifying a destination display at a station or airport, a departure time, an arrival time, etc. It is becoming.

  Advantages of using this liquid crystal display device include that it consumes less power than a light bulb display and is excellent in miniaturization. On the other hand, as a liquid crystal display device, a liquid crystal display panel, a backlight for illuminating the display panel, and a large number of component parts are included. Due to the large number of component parts, the display device is expensive. There is a problem that the thickness of the device itself increases.

  However, the biggest problem with this liquid crystal display device is that the viewing angle is narrow, so that the visibility from the side of the display device is extremely high even though the visibility from the front is excellent. bad. Improvements are currently being made to remedy this problem, but it has not yet been realized as a display device with sufficient visibility.

  On the other hand, in order to improve the problems of the liquid crystal display device, recently, an organic electroluminescence (organic EL) element has been developed, and its application to such a display device is being studied. Since this organic EL element is a light emitting element that emits light by itself, it does not require a light source such as a backlight unlike a liquid crystal display device, so that not only the number of components is reduced, but also the thickness of the device. Further, it can be made thin, can be reduced in weight, and can have a wide viewing angle. Therefore, it is suitable for use in a display device.

  As shown in FIG. 10, the light-emitting device provided with this organic EL element forms a first electrode layer 82 made of a transparent conductive film made of ITO (Indium Tin Oxide) on a transparent glass substrate 81. An organic light emitting layer 83 such as α-NPD or Alq3 is stacked on the electrode layer 82, and a second electrode layer 84 such as lithium fluoride or aluminum is formed on the organic light emitting layer 83. Thus, one end portions of the first and second electrode layers 82 and 84 are led to the end portion of the glass substrate 81 along the surface of the glass substrate 81.

  Since these electrode layers 82 and 84 and the organic light emitting layer 83 are vulnerable to moisture and oxygen in the outside air, these first and second electrode layers 82 and 84 and the organic light emitting layer 83 are made of glass or Sealing is performed using a protective plate 85 such as stainless steel. For this sealing, a UV curable adhesive 86 is applied to the peripheral edge of the protective plate 85, and is attached to the surface of the glass substrate 81 so as to cover the organic light emitting layer 83, and this attached UV curable adhesive is attached. The adhesive 86 is subjected to UV exposure in a state where light is shielded so that the internal organic light emitting layer 83 is not irradiated with UV, and the adhesive 86 is cured and hermetically sealed.

  However, in such a sealing configuration using the UV curable adhesive 86, it is difficult to completely shut off gas and moisture. For this reason, the internal space of the sealed sealing material 85 is difficult. A desiccant (not shown) is used to adsorb gas or moisture released inside or gas or moisture that permeates through the sealing portion such as the adhesive 86 and enters the internal space of the container. ) Is built-in.

  In addition, the first and second electrode layers 82 and 84 are also used as terminals for external connection. However, the terminal part also deteriorates in airtightness, so that oxygen and moisture that enter during lighting can be lost. For this reason, there are problems such as a decrease in luminous efficiency, generation of dark spots, and enlargement of the dark spots.

  Furthermore, since a UV-type adhesive is used for sealing, UV light leaks and reaches the organic light-emitting layer during the curing operation of the adhesive, not only deteriorating the organic light-emitting layer, but also bonding. The cost was increased by the use of chemicals.

  The present invention has been made in view of the above-described conventional problems, and an organic light emitting layer sandwiched between first and second electrode layers is interposed between a glass substrate and a protective plate, and a bonding metal. By providing a light emitting device with sufficiently improved hermeticity by sealing by anodic bonding with a layer interposed, the problem to be solved is that a reliable hermetic sealing configuration can be achieved. There is in point to do.

  As a first means for solving the above problems, the present invention provides a glass substrate formed of a moisture-impermeable material, a first electrode layer formed on the glass substrate, and an electrode layer disposed on the electrode layer. An organic light emitting layer provided, a second electrode layer laminated so as to sandwich the organic light emitting layer with the first electrode layer, and a bonding metal layer disposed in a peripheral portion of the glass substrate, A protective plate made of a moisture-impermeable material that is in contact with the metal layer and disposed opposite to the glass substrate, and the glass substrate and the protective plate are anodically bonded via a bonding metal layer. It is sealed.

  According to the present invention, as a second means for solving the above-described problem, the bonding metal layer is formed at the same time as the first or second electrode layer using the same material as the first or second electrode layer. It is formed.

  As a third means for solving the above problems, the present invention includes at least one connection terminal provided so as to penetrate through the glass substrate and connected to one of the first and second electrode layers. And the other electrode layer not connected to the connection terminal extends to the periphery of the glass substrate to form a bonding metal layer.

  As a fourth means for solving the above-mentioned problems, the present invention is characterized in that a semiconductor film is interposed between the glass substrate and at least the first electrode layer.

  According to the present invention, the first and second electrode layers formed on one plane of the glass substrate and the protective plate made of a moisture-impermeable material protecting the organic light emitting layer are anodically bonded through the bonding metal layer. By sealing, the metal layer and the glass substrate and the metal layer and the protective plate can be more firmly fixed, so that the defense performance such as gas and moisture from the outside is improved, and the luminous efficiency is reduced. Generation of dark spots and the like can be suppressed, and an inexpensive adhesive can be formed because no adhesive is used.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  First, as shown in FIG. 1, a light emitting device according to the present invention includes two glass substrates 11 containing a non-moisture permeable transparent rectangular alkali metal ion formed through the glass substrate 11. External connection terminals 12 and 12 'are provided. A first electrode layer (positive electrode layer) 13 made of a transparent conductive film such as ITO is formed on the one connection terminal 12, and an organic material such as α-NPD or Alq 3 is formed on the electrode layer 13. The light emitting layer 14 is laminated.

  One end of the organic light emitting layer 14 extends on the surface of the glass substrate 11 along the side surface of the first electrode layer 13 so as to cover the end of the first electrode layer 13.

  Further, a conductive film such as lithium fluoride or aluminum is formed on the organic light emitting layer 14 in the same direction in which the organic light emitting layer 14 extends so that one end portion thereof extends to the surface of the glass substrate 11. A second electrode layer (negative electrode layer) 15 made of is formed and is connected to another connection terminal 12 ′ penetrating the glass substrate 16.

  In this way, the bonding metal layer 16 is formed on the peripheral portion of the glass substrate 11 on which the electrode layers 13 and 15 and the organic light emitting layer 14 are formed, and the inside is formed in a concave shape on the metal layer 16. A protective plate 17 made of a glass material is disposed so as to face the glass substrate 11. The glass substrate 11 and the protective plate 17 are bonded by anodic bonding using the bonding metal layer 16. In this anodic bonding, the glass substrate 11 containing alkali metal ions and the bonding metal layer 16 or the smooth surface of the metal layer 16 and the protective plate 17 are brought into contact with each other at a temperature at which thermal diffusion of the alkali metal ions occurs. A direct current voltage is applied between the glass substrate 11 and the protective plate 17 and the bonding metal layer 16 to generate an electrostatic attractive force between the glass substrate 11 and the protective plate 17 and the metal layer 16. A chemical bond is generated at the interface between the plate 17 and the metal layer 16 to firmly fix them.

  For example, a positive voltage is applied to the bonding metal layer 16 and a DC voltage is applied to the glass substrate 11 and the protective plate 17 so as to be a negative voltage or a ground voltage. is there. The protective plate 17 preferably has substantially the same thermal expansion coefficient as that of the glass substrate 11, and the surface roughness of the joint surface must be suppressed to 0.2 μm or less.

  According to the light emitting device configured as described above, the glass substrate 11 and the protective plate 17 are firmly fixed by anodic bonding through the bonding metal layer 16, so that the effect of blocking the outside from the inside is achieved. Is significantly improved, and it is possible to suppress the decrease in luminous efficiency during lighting and the generation and expansion of dark spots.

  A method for manufacturing the light emitting device will be described in detail with reference to FIG.

  That is, as shown in FIG. 2 (a), as shown in FIG. 2 (b), a glass substrate 11 made of a transparent glass material containing 2% or more of alkali components such as 1A group sodium, potassium, lithium, etc. Two connection terminals 12 and 12 ′ that are spaced apart from each other and penetrate the glass substrate 11 are hermetically sealed. Next, as shown in FIG. 2C, a bonding metal layer 16 is formed on the peripheral portion of the glass substrate 11, and the end surface of one connection terminal 12 is covered on the inner glass substrate 11 surface of the bonding metal layer 16. As shown in FIG. 2D, the first electrode layer 13 made of ITO is formed by sputtering.

  As shown in FIG. 2E, an organic light emitting layer 14 such as α-NPD or Alq3 is formed on the first electrode layer 13 by a vacuum deposition method. As shown in FIG. 2 (f), a second electrode layer 15 made of LiF, Al, or the like is formed on the organic light emitting layer 14, and the electrode layer 15 is formed on the glass substrate 11. It is connected to another connection terminal 12 '.

  Then, a protective plate 17 having a recess 18 that covers the first and second electrode layers 13 and 15 and the organic light emitting layer 14 is brought into contact with the bonding metal layer 16 at the end face thereof on the glass substrate 11. Be placed. In this state, a positive voltage is applied to the bonding metal layer 16 and the glass substrate 11 and the protective plate 17 are set to a negative voltage or a ground voltage, so that the light emitting device is formed.

  By configuring in this way, the bonding metal layer 16 can be independently formed on the glass substrate 11, so that a material suitable for sealing can be freely selected and used.

  The bonding metal layer 16 can be formed at the same time using the same material as that of the first electrode layer 13 when the first electrode layer 13 is formed.

  In addition, the detailed description is abbreviate | omitted by attaching | subjecting the same code | symbol about the part demonstrated in FIG.

  That is, the process shown in FIGS. 3A to 3B is the same as the process from FIGS. 2A to 2B, but as shown in FIG. At the same time as forming the first electrode layer 13, a bonding metal layer 16 is formed on the periphery of the glass substrate 11 with the same material as the first electrode layer 13.

  The subsequent steps from FIG. 3D to FIG. 3F are the same as the steps in FIG. 2E to FIG. 2G, and detailed description thereof will be omitted. Transparent conductive material is used.

  By forming the light emitting device in such a process, the number of manufacturing processes can be reduced as compared with the case where the bonding metal layer 16 is separately formed, and the manufacturing efficiency can be improved. The light emission direction in this case is the sealing material direction because the Al material is used for the first electrode layer 13.

  Further, the bonding metal layer 16 can be manufactured so as to be formed together with the formation of the second electrode layer 15.

  That is, the process from FIG. 4A to FIG. 4B is the same as the process from FIG. 2A to FIG. 2B, but after that, as shown in FIG. The first electrode layer 13 is formed on the surface of the glass substrate 11 on the 12 side, and then the organic light emitting layer 14 is formed on the first electrode layer 13 as shown in FIG. Thereafter, as shown in FIG. 4E, a second electrode layer 15 made of an Al material is formed on the organic light emitting layer 14. At this time, the second electrode is also formed on the periphery of the glass substrate 11. A bonding metal layer 16 is formed simultaneously with the same material as the layer 15.

  A protective plate 17 having a recess 18 that covers the first and second electrode layers 13 and 15 and the organic light emitting layer 14 is brought into contact with the glass substrate 11 by bringing the end surface into contact with the bonding metal layer 16. Opposed to each other. In this state, a positive voltage is applied to the bonding metal layer 16 and a negative or ground voltage is applied to the glass substrate 11 and the protective plate 17 side, whereby the first and second electrode layers 13 and 15 and the bonding metal layer 16 are mutually connected. The light-emitting device is manufactured by sealing the gap by anodic bonding.

  With this configuration, the bonding metal layer 16 can be formed as it is using the same material as the second electrode layer 15, so that the manufacturing process can be simplified. The light emission direction in this case is the glass substrate 11 side opposite to the second electrode layer 15 using the Al material.

  In the above description, a case is described in which the bonding metal layer 16 is formed in the peripheral portion of the glass substrate 11 and the anodic bonding is performed so that the end face of the protective plate 17 having the recess 18 is in contact. As shown in FIG. 5, a bonding metal layer (wall) 16 having a height sufficient to enclose the first and second electrode layers 13 and 15 and the organic light emitting layer 14 in the peripheral portion of the glass substrate 11 is formed. It is also possible to place the protective plate 17 formed flat without providing the recess 18 on the other end side of the metal layer 16 and to form them by anodic bonding.

  If comprised in this way, since the protective plate 17 can be formed with a simple flat glass material etc., it becomes possible to abbreviate | omit trouble and processing, such as providing the recessed part 18.

  FIG. 6 shows a case where the first and second electrode layers 13 and 15 are reversed. At this time, as a material for the first electrode layer 13, a layer of LiF and Al is provided on the surface of the glass substrate 11 by a vacuum deposition method, and α-NPD and Alq 3 are stacked as an organic light emitting layer 14 thereon. On this organic light emitting layer 14, the 2nd electrode layer 15 which consists of transparent conductive films, such as ITO formed by sputtering method, was set as the structure. When a material such as Al is used as the first electrode layer 13 in this way, the connecting terminal 12 led out to the back side of the glass substrate 11 because the direction of the protective plate 17 is configured as the light emitting surface side. , 12 ′ have no effect on the light emitting surface, and there is no possibility that the connection terminals 12, 12 ′ are shielded from light, so that there is an effect that the wiring can be freely routed.

  Further, as shown in FIG. 7, the first electrode layer is formed so that the connection terminal 12 provided through the glass substrate 11 has a single configuration, and the first electrode layer 13 is connected to the connection terminal 12. 13 is formed on the glass substrate 11, and the second electrode layer 15 formed on the upper side of the organic light emitting layer 14 is not only extended to the surface of the glass substrate 11, but also the glass substrate along the surface of the glass substrate 11. It is good also as a structure formed even to the 11 peripheral part.

  As described above, by using the second electrode layer 15 as the external connection and the bonding metal layer 16, the number of connection terminals 12, 12 'can be reduced, and the man-hours associated therewith can be reduced. This contributes to shortening the working time.

  Further, as shown in FIG. 8, a SiO 2 layer (semiconductor layer) 19 is formed on the surface of the glass substrate 11, and the connection terminals 12 and 12 ′ are formed so as to penetrate the glass substrate 11 through the semiconductor layer 19. Then, the first electrode layer 13, the second electrode layer 15, and the organic light emitting layer 14 sandwiched between the electrode layers 13, 15 are formed on the semiconductor film 19.

  In the light emitting device having the semiconductor layer 19, the semiconductor layer is formed on the surface of the glass substrate 11 as shown in FIG. 9A and on the plane portion excluding the peripheral portion of the glass substrate 11 as shown in FIG. 19 is formed. The connection terminals 12 and 12 'are formed on the glass substrate 11 on which the semiconductor layer 19 is formed as shown in FIG. 9C, and the manufacturing method described above is used as shown in FIGS. These are manufactured in the same process, and the same parts are denoted by the same reference numerals, and detailed description thereof is omitted.

1 is a cross-sectional view showing a first embodiment of a light emitting device according to the present invention. Process explanatory drawing for demonstrating the manufacturing process of a light-emitting device similarly. Process explanatory drawing for demonstrating the manufacturing process by the other method similarly. Process explanatory drawing for demonstrating the manufacturing process by a different method similarly. Sectional drawing which similarly shows 2nd Embodiment. The perspective view which similarly shows 3rd Embodiment of the light-emitting device which concerns on this invention. Sectional drawing which similarly shows 4th Embodiment. Sectional drawing which similarly shows 5th Embodiment. Process explanatory drawing for demonstrating the manufacturing process of the light-emitting device which concerns on 5th Embodiment similarly. Sectional drawing which shows the conventional light-emitting device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11: Glass substrate 12,12 ': Connection terminal 13: 1st electrode layer 14: Organic light emitting layer 15: 2nd electrode layer 16: Metal layer for joining 17: Protection board 19: Semiconductor layer

Claims (4)

A glass substrate formed of a moisture-impermeable material;
A first electrode layer formed on the glass substrate;
An organic light emitting layer disposed on the electrode layer;
A second electrode layer laminated to sandwich the organic light emitting layer with the first electrode layer;
A bonding metal layer disposed on the periphery of the glass substrate;
A protective plate formed of a non-breathable material in contact with the metal layer and disposed opposite to the glass substrate;
A light-emitting device, wherein the glass substrate and the protective plate are sealed by anodic bonding through a bonding metal layer.   2. The light emitting device according to claim 1, wherein the bonding metal layer is formed at the same time when the first or second electrode layer is formed using the same material as the first or second electrode layer.   At least one connection terminal provided so as to penetrate through the glass substrate and connected to one of the first and second electrode layers is provided, and the other electrode layer not connected to the connection terminal is provided around the glass substrate. The light-emitting device according to claim 1, wherein the light-emitting device extends to a portion to form a bonding metal layer.   4. The light emitting device according to claim 1, wherein a semiconductor film is interposed between the glass substrate and at least the first electrode layer. 5.

Images