JP2007220397A - Connection structure of voltage driving type element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a leakage current of an inorganic EL element without changing the structure of the inorganic EL element, in a connection structure for connecting the inorganic EL element and a driving circuit via wiring. <P>SOLUTION: The inorganic EL element 10 is formed on a glass substrate 11 wherein a pair of insulating layers 13, 15 sandwiches a luminescent layer 14 from both sides and a pair of electrodes 12, 16 sandwiches them from their outside. A connection part of the wiring 30 of a first electrode 12 and a driving circuit 20 is electrically connected by capacity coupling in a state where an insulation layer 40 for a capacitor used as a capacitor made of same material as a second insulation layer 15 for structuring the inorganic EL element 10 is inserted in series between the wiring 30 and the driving circuit 20. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a connection structure in which a voltage-driven element such as a light emitting element utilizing an electroluminescence (EL) phenomenon is connected to an external circuit.

  For example, inorganic EL elements are known as voltage driven elements. In general, the inorganic EL element has a first electrode, a first insulating layer, a light emitting layer, a second insulating layer, and a second electrode, which are sequentially stacked, and is interposed between the first and second electrodes. The light emitting layer emits light by applying a voltage.

  In addition, such an inorganic EL element has a wiring electrically connected to the inorganic EL element and a drive circuit as an external circuit electrically connected to the inorganic EL element via a flexible printed wiring board or a bonding wire. By connecting to the external circuit, it is connected to the external circuit.

As described above, the inorganic EL element is formed by sandwiching both sides of the light emitting layer with a pair of insulating layers and further sandwiching the outside with a pair of electrodes. However, since the drive voltage is relatively high, the cost of the drive circuit is low. Becomes higher. Therefore, conventionally, as a method for lowering the drive voltage of the inorganic EL element, a method for increasing the capacity of the insulating layer has been proposed (see, for example, Patent Document 1 and Patent Document 2).
JP-A-1-107495 Japanese Patent Laid-Open No. 2004-234889

When the insulating layer of the inorganic EL element is simply thinned to increase the capacity, the withstand voltage is lowered, which is insufficient for driving the inorganic EL element. Conventionally, an Al ₂ O ₃ film is used as the insulating layer. ATO by a TiO ₂ film and formed by alternately stacking Al ₂ O ₃ / TiO ₂ multilayer structure film (hereinafter referred to as ATO film) used to increase the ratio of the TiO ₂ film occupied in the ATO film Even if the film is thinned, the withstand voltage can be secured.

  However, the inorganic EL element using the ATO film has a large leakage current because the ATO film is thin. Further, when the leakage current increases, there is a problem that power consumption for obtaining necessary element characteristics increases and reliability of the element decreases.

  In any case, it is not limited to such an example of an inorganic EL element, and in any case, it is preferable to change the configuration of the voltage-driven element side to suppress the leakage current because it causes various problems in the voltage-driven element. Absent.

  The present invention has been made in view of the above problems. In a connection structure in which a voltage-driven element and an external circuit are connected via a wiring, the voltage-driven element can be used without changing the configuration of the voltage-driven element. An object is to prevent leakage current of the element.

  In order to achieve the above object, the present inventor has studied a method for suppressing the leakage current of the voltage driven element.

  In the case of a voltage-driven element, in order to make the element function for a necessary time, when the voltage-driven element is made to function, a voltage having a stronger electric field strength is applied and held for a certain period of time than the voltage when the element is not made to function. . When the voltage-driven element is not functioned, the voltage is returned to a voltage that weakens the electric field strength.

  Therefore, it is necessary to suppress the leakage current while maintaining the electric field strength. In addition, since the switching of these functions is alternating, it is necessary not to disturb the function of alternating current.

  Based on such examination results, it was considered to insert a capacitor between the external circuit for driving the voltage-driven element and the voltage-driven element. This can be expected to suppress the leakage current when the voltage is held at a constant voltage.

  The present invention has been made based on such an idea. In the connection structure in which the voltage-driven element (10) and the external circuit (20) are connected via the wiring (30), the wiring (30) And at least one of the connections between the external circuit (20) and the external circuit (20) is electrically connected by capacitive coupling with a capacitor (40) inserted in series between the wiring (30) and the external circuit (20) It is characterized by that.

  According to this, since the DC component can be cut by the capacitor (40) provided between the wiring (30) and the external circuit (20), the voltage driven element can be changed without changing the configuration of the voltage driven element (10). The leakage current of (10) can be prevented.

  Here, the capacitor (40) may be disposed between the external circuit (20) and the voltage driven element (10), and may be disposed on the external circuit (20) side, or the voltage driven element (10) may be disposed. You may provide in the support substrate (11) side provided.

  In addition, when the voltage-driven element (10) is formed on the support substrate (11) and includes the dielectric (13, 15), a capacitor (on the support substrate (11)) ( 40) may be made of a thin film dielectric made of a material having a higher dielectric constant than the dielectrics (13, 15) constituting the voltage-driven element (10).

  The capacitor (40) inserted between the wiring (30) and the external circuit (20) is preferably higher than the capacity of the voltage driven element (10), and constitutes the voltage driven element (10). If it is made of a material having a dielectric constant higher than that of the dielectric (13, 15), it is easy to increase its capacity.

  In addition, when the voltage-driven element (10) is formed on the support substrate (11) and includes the dielectric (13, 15), a capacitor (on the support substrate (11)) ( 40) may be made of a thin film dielectric made of the same material as the dielectrics (13, 15) constituting the voltage driven element (10).

  According to this, a new process for forming the capacitor (40) disposed on the support substrate (11) is unnecessary, and cost reduction is expected.

  Here, a light-emitting element (10) using an electroluminescence phenomenon can be adopted as the voltage-driven element. As such a light-emitting element, both sides of the light-emitting layer (14) are provided on a pair of insulating layers (13). 15), and an inorganic EL element (10) in which the outside is sandwiched between a pair of electrodes (12, 16).

  Moreover, such an inorganic EL element (10) may be driven by a segment type driving method.

  When the inorganic EL element (10) is used in a segment type, since a region that does not emit light, that is, a non-light emitting region is large, if this non-light emitting region is a wiring (30), a capacitor (such as a dielectric) on the wiring (30) ( When 40) is arranged, the arrangement area of the capacitor (40) can be increased, and the capacity of the capacitor (40) can be easily increased.

  When the voltage-driven element is an inorganic EL element (10), the entire capacity of the electrical path to the external circuit (20) on one side of the light emitting layer (14) and the other of the light emitting layer (14) The total capacity of the electrical path to the external circuit (20) on the side is preferably equal.

  Inorganic EL elements are usually driven by a sine wave or square wave alternating current. At this time, in the electrical path to the external circuit located on both sides of the light emitting layer (14), if the capacitances of the insulating layers (13, 15) and the capacitor (40) are made the same, the bias of charge can be suppressed, and the voltage-luminance characteristics. Is preferable because it is possible to reduce the change with time.

  In addition, the code | symbol in the parenthesis of each means described in a claim and this column is an example which shows a corresponding relationship with the specific means as described in embodiment mentioned later.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, parts that are the same or equivalent to each other are given the same reference numerals in the drawings in order to simplify the description.

(First embodiment)
FIG. 1 is a diagram showing a schematic cross-sectional configuration of a connection structure of an inorganic EL element 10 as a voltage driven element according to the first embodiment of the present invention.

  The connection structure of this embodiment is roughly driven by an inorganic EL element 10 that is a voltage-driven element, a wiring 30 that is electrically connected to the inorganic EL element 10, and driving as an external circuit that drives the inorganic EL element 10. The circuit 20 is provided, and the wiring 30 and the external circuit 20 are electrically connected.

  The inorganic EL element 10 includes a first electrode 12, a first insulating layer 13, a light emitting layer 14, and a second insulating layer on one surface of a glass substrate 11 that is a support substrate of a voltage-driven element and is an insulating substrate. 15 and the second electrode 16 are sequentially laminated.

  In other words, the inorganic EL element 10 is formed by sandwiching both sides of the light emitting layer 14 between the pair of insulating layers 13 and 15 and sandwiching the outside between the pair of electrodes 12 and 16. Here, at least the light extraction side of the first electrode 12, the first insulating layer 13, the second insulating layer 15, and the second electrode 16 is made of a light-transmitting material.

  The first electrode 12 and the second electrode 16 are made of a transparent ITO (Indium Tin Oxide) film. A portion where the first electrode 12 and the second electrode 16 intersect with each other together with the first insulating layer 13, the second insulating layer 15, and the light emitting layer 14 sandwiched between the electrodes 12, 16. Is configured.

  Then, by applying an AC voltage between the first electrode 12 and the second electrode 16, the light emitting layer 14 emits light in this pixel. In this example, the light of the light emitting layer 14 is transmitted through the first insulating layer 13, the first electrode 12 and the glass substrate 11, and is extracted from the other surface of the glass substrate 11.

  The light emitting layer 14 is made of, for example, a semiconductor material such as ZnS or ZnSe, and Mn, Tb, Sm, or the like can be used as the light emission center. When Mn is used as the light emission center, yellow-orange light is emitted, when Tb is used, green light is emitted, and when Sm is used, red light is emitted. In this example, the light emitting layer 14 is a ZnS: Mn film.

The first insulating layer 13 and the second insulating layer 15 are formed by alternately stacking an ATO film, an HfO ₂ film and a TiO ₂ film, in which Al ₂ O ₃ films and TiO ₂ films are alternately stacked. HTO film, ZrO ₂ film and TiO ₂ film alternately stacked ZTO film, transparent electrical insulation composed of dielectric such as TiO ₂ , Al ₂ O ₃ , SiO ₂ , Si ₃ N ₄ It is a sex film. These can be formed by the ALE method (atomic layer epitaxial growth method), sputtering, CVD, or the like.

In this embodiment, the 1st insulating layer 13 and the 2nd insulating layer 15 consist of an ATO film | membrane, and were formed into a film by the ALE method. Specifically, in this example, the ATO film has an Al ₂ O ₃ film thickness of 5 nm, a TiO ₂ film thickness of 30 nm, and the number of layers is the same as that of the Al ₂ O ₃ film. There are 6 layers and 5 layers of TiO ₂ films.

Considering the case where the ATO film is formed on the atomic layer order using the ALE method, the film thickness per layer of the Al ₂ O ₃ film is preferably 0.5 nm to 100 nm. In case where the film thickness per one layer of the Al ₂ O ₃ film is thinner than 0.5 nm, the Al ₂ O ₃ film does not function as an insulator, if thicker than 100nm, the effect of improving the breakdown voltage of the laminate structure This is because of a decrease.

  Here, the application of the AC voltage between the first electrode 12 and the second electrode 16 is performed by the drive circuit 20 as an external circuit. The configuration of the connecting portion between the first electrode 12 and the second electrode 16 and the drive circuit 20 is based on a conventional general configuration, and the first electrode 12 and the second electrode 16 are respectively connected to the drive circuit 20. It extends to the peripheral part of the glass substrate 11, and this extended part is used as a wiring, and this wiring and the drive circuit 20 are connected.

  In FIG. 1, the wiring 30 of the first electrode 12 is shown, and the wiring of the second electrode 16 is omitted. The wiring 30 is made of an ITO film integrated with the first electrode 12, and this ITO film is extended to the peripheral portion of the glass substrate 11.

  A capacitor insulating layer 40 as a capacitor is laminated on the connection portion of the wiring 30 to the drive circuit 20, and further, on the capacitor insulating layer 40, electrical connection with the drive circuit 20 is performed. The connection electrodes 50 are stacked.

  That is, the connection portion between the wiring 30 and the drive circuit 20 is electrically connected by capacitive coupling in a state where the capacitor insulating layer 40 as a capacitor is inserted in series. The capacitor insulating layer 40 is provided on the glass substrate 11 on which the inorganic EL element 10 is formed.

  Here, the capacitor insulating layer 40 is made of the same insulating film material as the first insulating layer 13 and the second insulating layer 15. That is, in this example, the capacitor insulating layer 40 is made of a thin film dielectric made of the same material as the insulating layers 13 and 15 as dielectrics constituting the inorganic EL element 10.

  In this example, the capacitor insulating layer 40 is formed by the same film formation process as that of the second insulating layer 15, that is, made of the same material as that of the second insulating layer 15.

  The connection electrode 50 is made of the same material as that of the second electrode 16 and is formed by the same film formation process as that of the second electrode 16. The connection electrode 50 and the drive circuit 20 are electrically connected by FPC (flexible printed circuit board), wire bonding, or the like.

  Although the wiring of the second electrode 16 is omitted in the drawing, a part of the second electrode 16 is extended to the peripheral portion of the glass substrate 11. Here, the wiring of the second electrode 16 is electrically connected to the drive circuit 20 by FPC, wire bonding, or the like, as in a general EL.

  Next, a manufacturing method of the present inorganic EL element 10 will be described based on the above specific example. First, the first electrode 12 and the wiring 30 are formed on the glass substrate 11 by forming and patterning an optically transparent ITO film using a sputtering method or a photolithography technique.

  Further, an ATO film is formed as the first insulating layer 13 by the ALE method. Since the formation of the ATO film by the ALE method is the same as the formation of the second insulating layer 15 and the capacitor insulating layer 40 described later, the details will be described later.

  Next, a light emitting layer 14 made of ZnS: Mn is formed on the first insulating layer 13 by a vapor deposition method. The film thickness of the light emitting layer 14 is preferably 100 to 2000 nm. This is because when the thickness is less than 100 nm, the number of regions that do not contribute to light emission increases and the light emission efficiency is extremely reduced. When the thickness is greater than 2000 nm, the drive voltage increases.

  Next, an ATO film as the second insulating layer 15 and the capacitor insulating layer 40 is formed by the ALE method in the same manner as the first insulating layer 13. The ALE method for forming the ATO film as each of the insulating layers 13, 15, and 40 is specifically performed as follows.

Here, aluminum trichloride (AlCl ₃ ) and H ₂ O are used as raw materials for forming the Al ₂ O ₃ film, and titanium tetrachloride (TiCl ₄ ) and H ₂ O are used as raw materials for forming the TiO ₂ film.

First, as a first step, an Al ₂ O ₃ film is formed using AlCl ₃ as an Al source gas and H ₂ O as an oxygen (O) source gas. In the ALE method, source gases are alternately supplied to form films one atomic layer at a time.

Accordingly, in this case, AlCl ₃ is introduced into the reaction furnace with a carrier gas of nitrogen (N ₂ ) for 1 second, and then a purge sufficient to exhaust the AlCl ₃ gas in the reaction furnace is performed.

Next, H ₂ O is similarly introduced into the reaction furnace with a nitrogen carrier gas for 1 second, and then a purge sufficient to exhaust the H ₂ O in the reaction furnace is performed. This cycle is repeated to form an Al ₂ O ₃ film having a predetermined thickness.

As a second step, a TiO ₂ film is formed using TiCl ₄ as a Ti source gas and H ₂ O as an oxygen source gas. Specifically, similarly to the first step, TiCl ₄ is introduced into the reaction furnace with a nitrogen carrier gas for 1 second, and then purge sufficient to exhaust the TiCl ₄ in the reaction furnace is performed.

Next, H ₂ O is similarly introduced into the reaction furnace with a nitrogen carrier gas for 1 second, and then a purge sufficient to exhaust the H ₂ O in the reaction furnace is performed. This cycle is repeated to form a TiO ₂ film having a predetermined thickness.

Thus, by repeating the second step of forming a first step and the TiO ₂ film to form Al ₂ O ₃ film, laminating the the Al ₂ O ₃ film and the TiO ₂ film alternately one layer Then, an ATO film having a predetermined thickness is formed. Then, the ATO film is patterned by etching or the like to form an ATO film as the first insulating layer 13 or the second insulating layer 15 and the capacitor insulating layer 40.

  Next, an ITO film as the second electrode 16 and the connection electrode 50 is formed on the second insulating layer 15 and the capacitor insulating layer 40 using a sputtering method or a photolithographic technique, respectively. Film formation and patterning are performed. Thus, the inorganic EL element 10 of this embodiment can be produced.

  Conventionally, the insulating film formed in the connection portion of the wiring 30 connected to the first electrode 12 and the external circuit 20 is removed by etching or the like, and the wiring 30 and the external circuit 20 are electrically connected. In this example, the insulating film formed in the connection portion with the external circuit 20 on the wiring 30 is not removed but left as the capacitor insulating layer 40, and the capacitor 40 is formed by forming the connection electrode 50. The external circuit 20 is connected by capacitive coupling.

  Thereby, in this embodiment, since the direct current component can be cut by the capacitor 40 provided between the wiring 30 and the external circuit 20, the inorganic EL element can be changed without changing the configuration of the inorganic EL element 10 as a voltage driven element. 10 leakage currents can be prevented.

  In FIG. 1, a capacitor in which the capacity of the capacitor insulating layer 40 in the connection portion was changed was manufactured, and an experiment was conducted to investigate how much leakage current can be suppressed by the capacity of the capacitor insulating layer 40. Here, the capacitance of the capacitor insulating layer 40 was changed by changing the area and thickness of the layer 40. The result is shown in FIG.

  FIG. 2 shows a case where the capacitor insulating layer 40 is not inserted, the case where the capacitor insulating layer 40 of 5.5 times the element capacity (capacity of the inorganic EL element 10) is inserted, and the case where the capacitor insulating layer 40 is 54 times larger. It is a figure which shows the relationship between the voltage applied to the inorganic EL element 10, and the leakage current about the case where it inserts.

  As shown in FIG. 2, the leakage current can be considerably suppressed by inserting the capacitor insulating layer 40. From the results shown in FIG. 2, the capacitance of the capacitor insulating layer 40 may be determined according to the target value of the drive voltage while considering the increase of the drive voltage.

  If the capacitor insulating layer 40 is inserted in series between the inorganic EL element 10 and the drive circuit 20, a voltage proportional to the inverse ratio of the respective capacities is applied, and the drive voltage for obtaining the same characteristics increases.

  Therefore, the capacitance of the capacitor insulating layer 40 is preferably higher than the element capacitance. For example, if the capacity of the capacitor insulating layer 40 is 10 times the capacity of the inorganic EL element 10, the required drive voltage is about 1.1 times, and if it is 50 times, the drive voltage is suppressed to 1.02 times. Can do.

  In this example, the capacitor insulating layer 40 as a capacitor is formed of the same material as the second insulating layer 15 that is a dielectric constituting the inorganic EL element 10, but the capacitor insulating layer 40 is formed of the first insulating layer. 13 may be formed of the same material as that of the first insulating layer 13 or a laminated film of the first insulating layer 13 and the second insulating layer 15.

  As described above, if the capacitor insulating layer 40 is composed of the insulating layers 13 and 15 as dielectrics constituting the inorganic EL element 10, the capacitor insulating layer is simultaneously formed by the film forming process of these insulating layers 13 and 15. 40 can be formed. As a result, a new process for forming the capacitor insulating layer 40 is unnecessary, and cost reduction is expected.

  In this case, in order to increase the capacity of the capacitor insulating layer 40, it is conceivable to make the capacitor insulating layer 40 thinner. In this case, it is necessary to change the film forming process of the capacitor insulating layer 40 with the insulating layers 13 and 15 of the inorganic EL element 10.

  Here, in order to form the capacitor insulating layer 40 simultaneously with the insulating layers 13 and 15 of the inorganic EL element 10 and realize an inexpensive manufacturing process, the film thickness of the capacitor insulating layer 40 is set to It is preferable to have the same thickness as the insulating layers 13 and 15. In this case, the capacitance of the capacitor insulating layer 40 can be increased by increasing the area of the connection electrode 50 formed on the capacitor insulating layer 40.

  In the above example, the dielectric of the same material as the insulating layers 13 and 15 constituting the inorganic EL element 10 is used as the capacitor insulating layer 40, but a different material may be used. That is, the capacitor insulating layer 40 may be made of a thin film dielectric made of a material having a higher dielectric constant than the insulating layers 13 and 15 as dielectrics constituting the inorganic EL element 10.

  As described above, the capacitor insulating layer 40 inserted between the wiring 30 and the external circuit 20 is desirably higher than the capacity of the inorganic EL element 10, and as described above, a material having a higher dielectric constant. If it is formed, the capacity can be easily increased.

  Examples of such a high dielectric constant material include tantalum oxide, barium titanate, strontium titanate, lead titanate, barium strontium titanate, lead zirconate titanate, and the like.

  Further, if the capacitor insulating layer 40 is not disposed in the display portion, the high dielectric material may not have translucency. The capacitor insulating layer 40 made of such a material can be formed by various film forming methods such as sputtering and CVD other than the ALE method described above.

  Further, in the present embodiment, the overall capacity of the electrical path to the drive circuit 20 on one side of the light emitting layer 14 is equal to the overall capacity of the electrical path to the drive circuit 20 on the other side of the light emitting layer 14. It is preferable.

  As described above, when the capacitor insulating layer 40 is inserted in series, the combined capacitance of the capacitor insulating layer 40 and the insulating layer on the inserted side changes as compared with a state where the capacitor insulating layer 40 is not inserted.

  In the example shown in FIG. 1, the electrical path to the first insulating layer 13, the first electrode 12, the wiring 30, the capacitor insulating layer 40, the connection electrode 50, and the drive circuit 20 with the light emitting layer 14 interposed therebetween. And the second insulating layer 15, the second electrode 16, the wiring on the second electrode 16 side (not shown), and the electric path to the drive circuit 20 are preferably different in capacitance in each electric path. Absent.

  Normally, an inorganic EL element is driven by an alternating current of a sine wave or a square wave. However, if the capacitances of the electrical paths formed on both sides of the light emitting layer are greatly different, a bias of charge occurs in the light emitting layer, resulting in luminance. -The change with time of the voltage characteristics becomes large.

  Therefore, even when the capacitor insulating layer 40 is inserted as described above, if the capacitances in both the electric paths are made equal, the bias of charge can be suppressed and the change with time of the voltage-luminance characteristics can be reduced. be able to. Here, that the capacity | capacitance in both electric paths is equal means not only making it equal completely but the thing which should just be equal in the range of +/- 10%.

(Second Embodiment)
FIG. 3 is a diagram showing a schematic cross-sectional configuration of the connection structure of the inorganic EL element 10 as the voltage driven element according to the second embodiment of the present invention.

  In the first embodiment, the capacitor 40 is provided on the support substrate 11 side on which the inorganic EL element 10 as a voltage-driven element is provided. However, the capacitor is provided between the drive circuit 20 and the inorganic EL element 10. It suffices if they are arranged between them, and they may be arranged on the drive circuit 20 side.

  As shown in FIG. 3, in the present embodiment, the capacitor 40 is made of a chip capacitor or the like, and is provided not in the glass substrate 11 as a support substrate but in the external circuit unit 21 having the drive circuit 20. For example, the external circuit unit 21 is configured by a circuit board or the like, and the capacitor 40 may be provided on the circuit board in front of the drive circuit 20.

  In this case as well, the entire capacitance of the electric path to the drive circuit 20 on the second electrode 16 side of the light emitting layer 14 and the drive circuit 20 including the capacitor 40 on the first electrode 12 side of the light emitting layer 14 are also provided. The total capacity of the electrical path is preferably equal.

(Third embodiment)
FIG. 4A is a diagram showing a schematic plan configuration of a connection structure of an inorganic EL element 10 as a voltage driven element according to the third embodiment of the present invention, and FIG. 4B is a general example as a comparative example. 1 is a diagram showing a schematic plan configuration of a connection structure of a typical inorganic EL element 10. In FIG. 4, hatching is performed for the purpose of identification.

  The inorganic EL element 10 in each of the above embodiments may be a dot matrix type driving method or a segment type driving method, but this embodiment is particularly suitable when the inorganic EL element 10 is driven by a segment type driving method. An example is given.

  First, in the comparative example shown in FIG. 4B, the first electrode 12 indicated by one-side oblique hatching is formed on the glass substrate 11. An inorganic EL element 10 having seven rectangular pixels 17 is formed on the first electrode 12. Each pixel 17 is point-hatched.

  Here, the entire inorganic EL element 10, that is, the pixel 17 as a whole, forms the number “8”. Of course, in each pixel 17, as shown in the above embodiment, the first electrode 12, the first insulating layer 13, the light emitting layer 14, the second insulating layer 15, and the second electrode 16 are stacked. It is configured, and for example, numbers from “0” to “9” can be displayed by causing each pixel 17 to emit light.

  As shown in FIG. 4B, when the inorganic EL element 10 is used in a segment type, a region that does not emit light, that is, a non-light emitting region is large. Here, the non-light emitting region is a region where the first electrode 12 is widely formed in addition to the pixel 17, and is the wiring 30 of the first electrode 12 in the inorganic EL element 10.

  Therefore, in FIG. 4A, the capacitor insulating layer and the connection electrode 50 similar to those of the above embodiment are formed on the wiring 30 located in the non-light emitting region as shown by cross hatching. Yes.

  Although not shown in FIG. 4A, the capacitor insulating layer only needs to be present below the connection electrode 50 and may be patterned as such, but the first electrode 12 including the pixel 17 may also be patterned. It may exist over the entire area.

  As described above, if the capacitor insulating layer and the connection electrode 50 are formed on the first electrode 12 in the non-light emitting region, that is, the wiring 30, the arrangement area of the capacitor insulating layer 40 can be increased. It is easy to increase the capacity.

  In the case of such a segment type, since the area of one segment that emits light, that is, the pixel 17 is large, there is a high probability that film defects such as the insulating layers 13 and 15 exist in the pixel 17.

  When such a film defect exists, the electric field in that portion becomes higher than that in a normal portion, and the leakage current increases. Therefore, it is effective to apply the present invention to such a segment type.

(Other embodiments)
In the first and second embodiments, the capacitor 40 is provided only on the wiring 30 on the first electrode 12 side of the inorganic EL element 10. However, the capacitor on the wiring on the second electrode 16 side is similar to this. The insulating layer 40 may be provided, or the capacitor 40 may be provided on the external circuit 20 side. Further, a capacitor may be provided for both the first electrode 12 side and the second electrode 16 side wiring.

  In the first and second embodiments, the intersection of the first electrode 12 and the second electrode 16 is the pixel 17. However, in the dot matrix type pixel configuration, the first electrode 12 and the second electrode 16. Are patterned into stripes intersecting each other to form matrix pixels.

  In this case, a capacitor may be provided for all of the plurality of first electrodes 12 and second electrodes 16, or a part of the first electrode 12 and the second electrode 16 or the first electrode 12. Alternatively, a capacitor may be provided only for one of the second electrodes 16. In short, the capacitor may be provided in at least one of the connection portions between the wiring and the external circuit.

  Moreover, as the inorganic EL element 10, the configuration of each of the electrodes 12, 16 and the light emitting layer 14 is not limited to that described in the above embodiment, and may be appropriately changed in design.

  Further, the voltage driven element may be a light emitting element utilizing an electroluminescence phenomenon other than the inorganic EL element described above. In addition, various devices can be used as long as they are driven by voltage.

It is a schematic sectional drawing of the connection structure of the inorganic EL element as a voltage drive type element which concerns on 1st Embodiment of this invention. It is a figure which shows the relationship between the voltage applied to the inorganic EL element, and the leakage current about the case where element capacitance is changed. It is a schematic sectional drawing of the connection structure of the inorganic EL element as a voltage drive type element concerning 2nd Embodiment of this invention. (A) is a schematic top view of the connection structure of the inorganic EL element as a voltage drive type element which concerns on 3rd Embodiment of this invention, (b) is a schematic plan view of the general connection structure as a comparative example. is there.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Inorganic EL element as a voltage drive type element, 11 ... Glass substrate as a support substrate,
12 ... 1st electrode, 13 ... 1st insulating layer, 14 ... Light emitting layer, 15 ... 2nd insulating layer,
16 ... 2nd electrode, 20 ... Drive circuit as external circuit, 30 ... Wiring,
40: An insulating layer for a capacitor as a capacitor.

Claims (9)

A voltage-driven element (10), a wiring (30) electrically connected to the voltage-driven element (10), and an external circuit (20) for driving the voltage-driven element (10), In the connection structure in which the wiring (30) and the external circuit (20) are electrically connected,
At least one of the connection portions between the wiring (30) and the external circuit (20) is a state in which a capacitor (40) is inserted in series between the wiring (30) and the external circuit (20). And a voltage-driven element connection structure, wherein the connection structure is electrically connected by capacitive coupling. The voltage-driven element connection structure according to claim 1, wherein the capacitor (40) is provided on the external circuit (20) side. The voltage-driven element (10) is formed on a support substrate (11),
The voltage-driven element connection structure according to claim 1, wherein the capacitor (40) is provided on the support substrate (11). The voltage-driven element (10) includes a dielectric (13, 15),
The capacitor (40) is composed of a thin film dielectric made of a material having a higher dielectric constant than the dielectrics (13, 15) constituting the voltage-driven element (10). The connection structure for a voltage-driven element according to claim 3. The voltage-driven element (10) includes a dielectric (13, 15),
The said capacitor | condenser (40) is comprised by the thin film dielectric material which consists of the same material as the said dielectric material (13,15) which comprises the said voltage drive type | mold element (10), The Claim 3 characterized by the above-mentioned. The connection structure of the voltage drive type element of description. The voltage-driven element connection structure according to any one of claims 1 to 5, wherein the voltage-driven element is a light emitting element (10) using an electroluminescence phenomenon. The light-emitting element is an inorganic EL element (10) in which both sides of a light-emitting layer (14) are sandwiched between a pair of insulating layers (13, 15) and the outside is sandwiched between a pair of electrodes (12, 16). The voltage-driven element connection structure according to claim 6. The voltage-driven element connection structure according to claim 7, wherein the inorganic EL element (10) is driven by a segment-type driving method. The total capacity of the electrical path to the external circuit (20) on one side of the light emitting layer (14) and the total capacity of the electrical path to the external circuit (20) on the other side of the light emitting layer (14). The voltage-driven element connection structure according to claim 7 or 8, wherein and are equal to each other.

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