JP4978438B2 - Deposition method - Google Patents

Description

  The present invention relates to a film forming method for forming a film containing a material containing a functional substance having various functions such as a light emitting function and a color forming function on a substrate.

  An organic light emitting diode (OLED), that is, an organic EL (electro luminescent) element, has attracted attention as a thin and light-emitting source, and an image display apparatus including a large number of organic EL elements has been developed. The organic EL element has a structure in which an organic thin film containing an organic EL substance as the functional substance is sandwiched between a pixel electrode and a counter electrode. Each of such organic EL elements can constitute a pixel in the image display apparatus.

The aforementioned image display device typically has an image display area and its peripheral area on, for example, an element substrate.
Here, the image display area is an area in which the above-mentioned many organic EL elements are arranged in a matrix, for example. In this case, a common organic thin film may be formed for all of these organic EL elements, but the organic thin film may be formed so that each of the organic EL elements has one organic thin film. . In the latter case, each pixel is distinguished from each other by, for example, forming an insulating film or a partition wall (so-called bank) for regulating the light emitting region.
On the other hand, the peripheral area is provided with a power supply circuit for supplying various signals to the organic EL element, various signal processing circuits, and input / output terminals used for exchanging signals with the outside. .
As such an image display device, for example, those disclosed in Patent Documents 1 and 2 are known.
JP 2005-259717 A JP 2006-51412 A

By the way, in the image display apparatus as described above, the organic thin film is formed on the element substrate by using, for example, a droplet discharge method (inkjet method). Here, the liquid means a solution in which the solute as the organic EL substance as an active ingredient is dispersed or dissolved in an appropriate dispersion medium or solvent (hereinafter sometimes referred to as “organic solution”).
In such a method for producing an organic thin film, the amount of organic solution held by each organic EL element or each pixel is the same in order to achieve uniform emission characteristics of all organic EL elements in the image display region. Is desirable. This is because, after the solvent is evaporated, the amount of the solute (that is, the organic EL substance) held by each organic EL element is substantially the same.

However, it is generally difficult to satisfy such a requirement. This is because the difference in the discharge mode of the droplets (for example, the difference in the amount of each droplet), the influence of the surface tension of the droplets, or the position within the element substrate surface after applying the organic solution. This is because a difference in the amount of the organic EL material held in each pixel can be caused by the influence of the difference in the partial pressure of the solvent molecules in the organic solution corresponding to the difference. In some cases, the organic EL material is also biased within one pixel.
In particular, the cause relating to the partial pressure of the solvent molecules is that the evaporation of the solvent in the central portion of the image display region is generally less active than that in the peripheral portion. In this case, the organic EL element in the peripheral portion is likely to have a smaller amount of organic EL material. A similar phenomenon also occurs inside a pixel located in a peripheral portion in the image display area. That is, the central portion of the pixel holds more organic EL material, and the peripheral portion holds less organic EL material.

Therefore, conventionally, in order to solve such a problem, for example, as in Patent Document 1, a so-called dummy pixel having a structure similar to that of the organic EL element on the image display area is provided on the peripheral area. (Patent Document 1 [Claim 1], [FIG. 12], [FIG. 4], etc.). According to this, the dummy pixel formation region can take charge of the portion where the amount of the organic EL material is reduced as described above. That is, the “evaporation promotion phenomenon in the peripheral portion” is generated in the dummy image formation region so that the organic EL element in the image display region is not affected by the phenomenon. As described above, all the pixels can hold substantially the same amount of the organic EL material.
However, in order to realize such an object, it is usually necessary to provide a relatively large number of dummy pixels. Accordingly, the peripheral area needs to have a relatively large area accordingly, and as a result, there is a possibility that the size of the entire apparatus may be increased.

On the other hand, in Patent Document 2, although the dummy pixels as described above are not provided, the “liquid medium” of the “functional liquid” that is the basis of the “film made of a functional material” with the same awareness of the problem as described above. And a film forming method in which “a solvent having the same or substantially the same vapor pressure” is applied to the “peripheral region of the film forming region” is disclosed (in the above, “” is disclosed in Patent Document 2 [Claim 1]. ]). Even when these “functional liquid” and “solvent” are vaporized at the same time, the above-described evaporation promotion phenomenon occurs with respect to the “solvent”. It becomes possible to have almost the same amount of organic EL material. In addition, in this method, “dummy pixels” are not provided in the peripheral region, that is, an organic solution is not applied to the peripheral region. (Patent Document 2 [0010]) has no advantage.
However, even in this Patent Document 2, there is no significant gap with the Patent Document 1 in terms of using the “peripheral area” (“peripheral area” in terms of terms used so far). The above-mentioned problems such as the expansion of the peripheral area and the increase in the size of the entire apparatus are still related.

  Note that the above-described problems can occur not only in the case of manufacturing organic EL elements but also in the case of manufacturing color filters and the like provided in liquid crystal display devices and the like. In this case, if the term “organic EL substance” is replaced with “coloring substance”, “substance that transmits only light having a predetermined wavelength”, etc., almost the same problem situation is exhibited.

The present invention has been made in view of the above-described problems, and allows all pixels in the image display region to hold substantially the same amount of functional substance while enabling the peripheral region surrounding the image display region to be narrowed. It is an object to provide a film formation method.
Another object of the present invention is to provide a film forming method capable of solving the problems related to this.

In order to solve the above-described problem, a light-emitting device according to a first aspect of the present invention includes a solute containing a functional substance in each of the first regions on the substrate and the small regions dividing the first region into a predetermined number. A first application step of applying a first material containing the first solvent and a solvent thereof; and applying a second material containing at least the same material as the solvent in a second region surrounding the first region on the substrate. 2 application step, and an evaporation step for evaporating both the solvent in the first material and the material in the second material, and the first region is added to the small region in the interior thereof. Including a partition region that partitions adjacent small regions among the small regions, one small region and one partition region constitute one unit region, and the second region in the second coating step The width includes a total width of the small regions in the first region, and the first region. In the case where the second material applied to the outside small area of the outside single unit area consisting of the outside small area and the outside partition area having the same arrangement structure as the one unit area is evaporated in the area, the outside area The time point at which the total amount of the second material applied to the small region evaporates is set to be substantially the same as the time point at which the total amount of the first material applied to the small region of the first region evaporates. It is set based on the product of the square root of the number of out-of-area small areas.
A first application step of applying a first material containing a solute containing a functional substance and a solvent thereof in each of the first areas on the substrate and dividing the first area into a predetermined number; A second application step of applying a second material containing the same material as the solvent on the substrate so as to surround the first region; and the solvent in the first material and the second material in the second material. An evaporation step for evaporating the material together, wherein the second application step connects the second material to a certain one small region located at the outermost contour of the first region. Applying to the outer second region and so that its volume corresponds to a value determined based on the unit volume of the first material applied for one of the subregions. To be implemented.

According to the present invention, the second material is applied so as to surround the first region, whereby the thickness of the first material in the first region after the evaporation step including the functional substance such as the organic EL substance is reduced. It can be made substantially uniform.
In addition, in the present invention, the volume of the second material to be applied to the second region (which, by definition, is included in the region “surrounding the first region”) can be appropriately determined. It has become. This is due to the following circumstances.
That is, since the “unit volume” defined above is a value defined for “one of the small regions”, a film forming method that involves a material application step for each small region as in the present invention. In terms of, in various cases, it can be said that the value has a qualification that can be a minimum unit or a reference unit. For example, in order to satisfy a condition (hereinafter, also referred to as “uniformization condition”) necessary for making the film thickness in the first region of the first material after the evaporation step substantially uniform, The value of “unit volume” can be used as a standard (in fact, the policy of providing “dummy pixels” described in the above [Problems to be solved by the invention] is based on such an idea. This is because in such a strategy, the organic solution applied to each of the dummy pixels (which is very close to the concept of “unit volume”) is completely This is because it can be considered as a standard for uniformizing the amount of organic EL material held in the pixel.)
Then, the volume of the second material to be applied to the second region is determined based on the “unit volume”. As the uniformizing condition, the “unit volume” is used as an intermediary. This means that the possibility of suitably determining the volume of the second material is guaranteed.
And the suitable volume which can be calculated | required in this way is directly linked with the suitable quantity of the said 2nd material.
From the above, according to the present invention, since the amount of the second material to be applied can be suitably limited while satisfying the homogenization condition, the second material is a peripheral region around the first region. Is not overoccupied.
Therefore, according to the present invention, it is possible to hold the substantially same amount of functional substance in all the small areas in the first area, and it is also possible to realize a narrow frame.

In the light emitting device of the present invention, the first region includes, in addition to the small region, a partition region for partitioning adjacent small regions among the small regions, one small region and one small region. The divided area constitutes one unit area, and the unit volume is arranged in the second area by an out-of-area small unit area and an out-of-area partitioned area having the same arrangement structure as the one unit area. Further, it may be configured to be determined based on the volume of the first material in the case where the first material is applied to one of the small outside regions.
According to this aspect, the first material may be applied to the “dummy pixel” described in the above [Problems to be Solved by the Invention] and “outside small area” basically in the same line. is assumed. The above-mentioned “unit volume” is determined based on the volume when the first material is applied to one of the small areas outside the region (and the volume of the second material is further increased). Determined based on "unit volume").
As such, in this aspect, from the viewpoint of the influence on the behavior of the first material and the second material in the evaporation process, if it is assumed that the “volume” of both materials can be equated, for example, Based on the amount of the second material when the dummy pixel is provided and the second material is applied to the formation region, the amount of the second material to be applied can be determined ( For example, when the first and second materials have the same composition, it is not necessary to make the above assumption.)
Therefore, according to this aspect, the above-described effects according to the present invention are more effectively achieved.
It should be noted that each area of “outside small area” and “outside partition area” and “outside one unit area” composed of these is actually secured on the substrate. That is not. Each of these regions is merely an “assumed existence” for suitably setting the “unit volume”. The term selection “when arranged and... Applied” in this embodiment implies such a situation.

In this aspect, the number of the one unit region outside the region that is supposedly arranged in the second region is determined so as to substantially uniform the film thickness in the first region of the first material after the evaporation step, The volume of the second material may be determined based on the total volume of the first material when the first material is applied to a plurality of small areas outside the region.
According to this, the technical idea of the above-described aspect is further promoted, and the volume of the second material is the case where the first material is applied to all the small areas outside the region consisting of the number satisfying the uniformization condition. , Based on the total volume. According to this, in principle, if the dummy pixel is provided and the second material is applied to the formation region, the amount of the second material is almost the same as the amount of the second material. It can be applied to the second region.
Therefore, according to this aspect, the above-described effect according to the present invention is more effectively achieved.
Incidentally, as in the case of the above-described embodiment, in this case, the peripheral region can be narrowed by at least the formation region of the above-described “partition region”. This is a remarkable and clear effect according to the present invention in comparison with the case where the “dummy pixel” is provided.

  In order to solve the above-described problem, a light-emitting device according to a second aspect of the present invention includes a solute containing a functional substance in each of the first regions on the substrate and each of the small regions dividing the first region into a predetermined number. And a first application step of applying a first material including the solvent and a second application of applying a second material including at least the same material as the solvent on the substrate so as to surround the first region. And an evaporation step for evaporating both the solvent in the first material and the material in the second material, wherein the second application step is such that the second material is the outermost portion of the first region. Connected to one small region located on the outer shell, in a second region outside the first region, and its surface area to a unit surface area of the first material applied for one of the small regions The process applied to match the value determined on the basis of, It is comprise embodiment.

According to the present invention, “surface area” is the central concept instead of “volume” described above. Although there is such a change, basically, in the description of the light-emitting device according to the first aspect of the present invention described above, the action understood by replacing “volume” with “surface area”, This is also achieved by the present invention.
Therefore, according to the present invention, it is possible to hold substantially the same amount of functional substance in all the small regions in the first region, and it is also possible to realize a narrow frame.

In the light emitting device of the present invention, the first region includes, in addition to the small region, a partition region for partitioning adjacent small regions among the small regions, one small region and one small region. The partitioned area constitutes one unit area, and the unit surface area is arranged in the second area with an out-of-area small unit area and an out-of-area partitioned area having the same arrangement structure as the one unit area. In addition, it may be configured to be determined based on the surface area of the first material when the first material is applied to one of the small areas outside the region.
According to this aspect, the above-described effect according to the present invention is more effectively exhibited for the same reason as described with respect to the aspect having the same concept having “volume” as a constituent element.
Note that the precautions regarding the “outside small area” and “outside partition area” and the “outside one unit area” are the same as described above.

In this aspect, the number of the one unit region outside the region that is supposedly arranged in the second region is determined so as to substantially uniform the film thickness in the first region of the first material after the evaporation step, The surface area of the second material is determined based on the total surface area of the first material when the first material is applied to the plurality of small areas outside the plurality of one area outside the plurality of areas. You may comprise.
According to this, the above-described effect according to the present invention is more effectively exhibited for the same reason as described with respect to the above-described aspect having the “volume” as a constituent element.

  In order to solve the above-described problem, a light-emitting device according to a third aspect of the present invention includes a solute containing a functional substance in each of the first regions on the substrate and each of the small regions that divide the first region into a predetermined number. And a first application step of applying a first material including the solvent and a second application of applying a second material including at least the same material as the solvent on the substrate so as to surround the first region. And a vaporizing step for evaporating both the solvent in the first material and the material in the second material, and the first region includes the small region in addition to the small region. Including a partition region that partitions between adjacent small regions, one small region and one partition region constitute one unit region, touch the outline of the first region, and One unit area outside the area (assuming that it is arranged away from the contour line) The term “outside one unit area” refers to an area composed of a small outside area and an outside partition area having the same arrangement structure as the one unit area). When the first material is applied and evaporated in a small area, the thickness of the first material is determined to be substantially uniform in the first area, and the second application step includes the step of The second material is applied so as to be applied to a distance determined based on the square root of the number of the one unit area outside the area as viewed from the outline of the first area.

According to the present invention, firstly, the second material is applied so as to surround the first region, thereby including a functional substance such as an organic EL substance in the first region of the first material after the evaporation step. It is possible to make the film thickness substantially uniform.
In addition, in the present invention, the size of the area around which the second material is to be applied around the first area can be appropriately determined. This is due to the following circumstances.
That is, in the present invention, the existence of “outside one unit region” including “outside small region” that is basically collinear with the concept of “dummy pixel” described in the above [Problems to be Solved by the Invention] is assumed. The “number” of the one unit region outside the region is determined so as to substantially uniform the film thickness in the first region of the first material after the evaporation step. The “number” defined here is based on the consideration of how many unit areas outside the area must be arranged to cover the area where the “evaporation promotion phenomenon” is expected to occur. It is a fixed number.
In the present invention, based on this “number”, more specifically, based on the “square root of the number”, the range (distance) of the region where the second material is to be applied is defined. Yes. Here, the reason why the “square root” appears is that “one unit area outside the area” is actually secured by the “number” determined as described above, and the second material is located in the small area outside the area. The amount of the second material in the case of being applied is the same as the amount of the second material to be applied in the present invention (that is, in the case where “outside one unit region” is not actually provided). It is in the technical idea to try. The relationship between this technical idea and the square root will be mentioned in the description of the later embodiments.
Thus, according to the present invention, the same amount of the second material as that in the case where the dummy pixel is provided is ensured (that is, while the equalization condition equivalent to that is satisfied), and the second material. The area where the coating is applied is preferably limited.
Therefore, according to the present invention, it is possible to realize a narrow frame while making it possible to hold substantially the same amount of functional substance in all the small regions in the first region.

In the light emitting device of the present invention according to the first to third aspects described above, the second material is applied to a space surrounded by a partition wall that divides a region surrounding the first region into a predetermined number of regions. It may be configured as follows.
According to this aspect, since the second material is applied to the space surrounded by the partition walls, for example, even if the substrate is tilted, the second material exists in a part of the substrate. Does not occur. Therefore, in the evaporation step, it is possible to uniformly evaporate the first material in the first region, and thus holding substantially the same amount of functional substance in all the small regions in the first region, More effectively.

In the light emitting device according to the first to third aspects of the present invention, the second material may include the solvent and not include the solute.
According to this aspect, since the second material does not contain a solute, the solute is not left around the first region after the evaporation step is completed. Therefore, for example, an electrode for supplying a current to the functional substance remaining in the small region can be installed in the region around the first region where the second material has been applied. For example, the peripheral area can be effectively used.

Moreover, in the light-emitting device which concerns on the 1st thru | or 3rd viewpoint of this invention, you may comprise so that a said 2nd application | coating process may be implemented before the said 1st application | coating process.
According to this, when the boiling point of the said solvent is comparatively low and vapor pressure is comparatively high, it can respond suitably. This is because, in such a case, since the spontaneous evaporation of the solvent is likely to be promoted, it is considered that the evaporation of the solvent in the first material proceeds even during the execution of the first application step. In this case, if the second material already exists, the evaporation phenomenon can be made uniform. If the first coating step and the second coating step are performed simultaneously or the latter is performed after the former, it is difficult to enjoy such benefits.

Or you may comprise so that the said 2nd application | coating process may be implemented simultaneously with the said 1st application | coating process.
According to this, contrary to the above, when the boiling point of the solvent is relatively high and the vapor pressure is relatively low, it is possible to cope with it suitably. In this case, contrary to the above, since there is no situation in which the spontaneous evaporation of the solvent is likely to be promoted, it is not particularly necessary to pay special attention to the execution timing of the first application step and the second application step. However, if that is the case, the first and second coating steps are the same coating step, and therefore it can be said that both are preferably performed simultaneously from the viewpoint of reducing the number of steps.
Thus, according to this aspect, it is possible to enjoy cost reduction due to reduction in the number of processes.
However, for the purpose of the present invention in general, the second coating step is performed after the first coating step when the boiling point of the solvent is relatively high and the vapor pressure is relatively low as described above. Or may be implemented before. In short, in this case, there is no need to pay attention to the evaporation during the first coating process, and from this point of view, it is not necessary to pay particular attention to the order of both processes.
Moreover, in said two aspects, the reference | standard which determines the height of a boiling point can be calculated | required in the temperature of 200 degreeC in 1 atmosphere. That is, it may be considered that the second coating step is performed in advance when the boiling point of the solvent is lower than 200 ° C., and the first and second coating steps are performed simultaneously when the boiling point of the solvent is lower than 200 ° C. it can.

In the light emitting device according to the first to third aspects of the present invention, the total number of the small regions dividing the first region is grouped into a plurality of small regions, and the first coating step includes the plurality of the small regions. Including the step of applying the first material to each of the small region groups, and the evaporation step may be performed individually so as to correspond to each of the plurality of small region groups. .
According to this aspect, typically, for example, the following film forming process is performed.
That is, first, the first material containing the functional substance A is applied to the first small region group, and then the evaporation process for the first material is performed. Second, the first material containing the functional substance B is applied to the second small region group, and then the evaporation step is performed. Hereinafter, the first material containing the functional substances C, D,... Is applied to the third, fourth,... Small region groups, and each evaporation step is performed next to each of the first materials.
In this case, the amount of the first material to be applied in each set including the application and evaporation steps is reduced as compared with the case where the first material is applied to all the small regions at once. . That is, in this case, the amount of the second material necessary for making the film thickness uniform in the first region of the first material becomes at least better. Therefore, the region where the second material is to be applied can be further narrowed in addition to the above.
As described above, according to this aspect, the effects according to the present invention described above are more effectively achieved.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. In these drawings and in each drawing after FIG. 12 to be referred to later, the ratio of dimensions of each part is appropriately changed from the actual one.

FIG. 1 is a plan view showing an example of an organic EL device manufactured by using the film forming method according to the present invention.
In FIG. 1, the organic EL device includes an element substrate 7 and various elements formed on the element substrate 7. Here, the various elements include the organic EL element 8, the scanning line 3 and the data line 6, the scanning line driving circuits 103A and 103B, the data line driving circuit 106, the precharge circuit 106A, and the counter electrode power line 201. Yes.

As shown in FIG. 1, a plurality of organic EL elements (light emitting elements) 8 are provided on an element substrate 7, and the plurality of organic EL elements 8 are arranged in a matrix. Each of the organic EL elements 8 includes a pixel electrode, a light emitting functional layer, and a counter electrode, and the light emitting functional layer is manufactured by the film forming method according to the present invention. These elements and their film forming methods will be described later.
The image display area 7a (corresponding to the “first area” in the present invention) is an area where the plurality of organic EL elements 8 are arranged on the element substrate 7. In the image display area 7 a, a desired image can be displayed based on individual light emission and non-light emission of each organic EL element 8. Hereinafter, the area excluding the image display area 7a on the surface of the element substrate 7 is referred to as a “peripheral area”.

  The scanning lines 3 and the data lines 6 are arranged so as to correspond to the respective rows and columns of the organic EL elements 8 arranged in a matrix. More specifically, as shown in FIG. 1, the scanning line 3 extends in the left-right direction in the drawing and is connected to scanning line driving circuits 103A and 103B formed on the peripheral region. On the other hand, the data line 6 extends along the vertical direction in the drawing and is connected to the data line driving circuit 106 formed on the peripheral region. A unit circuit (pixel circuit) P including the organic EL element 8 and the like described above is provided in the vicinity of each intersection of each scanning line 3 and each data line 6.

As shown in FIG. 2, the unit circuit P includes the organic EL element 8 described above, and also includes an n-channel first transistor 68, a p-channel second transistor 9, and a capacitor element 69.
The unit circuit P receives power from the current supply line 113. The plurality of current supply lines 113 are connected to a power source (not shown).
The source electrode of the p-channel type second transistor 9 is connected to the current supply line 113, while the drain electrode thereof is connected to the pixel electrode of the organic EL element 8. A capacitive element 69 is provided between the source electrode and the gate electrode of the second transistor 9. On the other hand, the gate electrode of the n-channel first transistor 68 is connected to the scanning line 3, its source electrode is connected to the data line 6, and its drain electrode is connected to the gate electrode of the second transistor 9.
In the unit circuit P, when the scanning line driving circuits 103A and 103B select the scanning line 3 corresponding to the unit circuit P, the first transistor 68 is turned on, and the data signal supplied via the data line 6 is transferred to the internal circuit P. It is held in the capacitor element 69. Then, the second transistor 9 supplies a current corresponding to the level of the data signal to the organic EL element 8. As a result, the organic EL element 8 emits light with a luminance corresponding to the level of the data signal.

On the peripheral region on the element substrate 7, a precharge circuit 106A is provided. The precharge circuit 106A is a circuit for setting the data line 6 to a predetermined potential prior to a data signal write operation to the organic EL element 8.
The counter electrode power supply line 201 (hereinafter simply referred to as “power supply line 201”) has a square shape in plan view so as to substantially follow the outline of the element substrate 7. The power supply line 201 supplies a power supply voltage such as a ground level to the counter electrode of the organic EL element 8. The power supply line 201 having the above-described shape corresponds to the counter electrode being formed in a rectangular shape as will be described later.
In the above description, an example in which all of the scanning line driving circuits 103A and 103B, the data line driving circuit 106, and the precharge circuit 106A are formed on the element substrate 7 has been described. Or a part may be formed in a flexible substrate. In this case, by providing appropriate terminals at both contact portions between the flexible substrate and the element substrate 7, electrical connection between the two can be achieved.

  An organic EL device having the above-described configuration in plan view includes a stacked structure as shown in FIG. 3 shows a cross-sectional view in which a viewpoint including the boundary between the image display area 7a in FIG. 1 and the peripheral area (reference numeral 93a in FIG. 3) is selected and viewed from the viewpoint.

As shown in FIG. 3, the stacked structure includes a circuit element thin film 11, a first interlayer insulating film 301, a second interlayer insulating film 302, a pixel electrode 13, and a light emitting function in order from the bottom in the figure with respect to the element substrate 7. The layer 18 and the counter electrode 5 are included.
Among these, the first and second interlayer insulating films 301 and 302 (hereinafter, simply referred to as “insulating films 301 and 302”) may prevent a short circuit between other conductive elements, or This contributes to realizing a suitable arrangement of the conductive elements in the laminated structure. Although these insulating films 301 and 302 can be made of various insulating materials with various thicknesses, it is preferable that the insulating films 301 and 302 are appropriately selected depending on the arrangement position and role of each insulating film in the laminated structure. Thickness and material may be selected.
More specifically, for example, the insulating films 301 and 302 are preferably made of SiO ₂ , SiN, SiON, or the like.

  The circuit element thin film 11 includes the first transistor 68 and the second transistor 9 included in the unit circuit P described above. Although the circuit element thin film 11 is drawn in a very simplified manner in the figure, the circuit element thin film 11 is composed of a semiconductor layer, a gate insulating film, a gate metal, etc. constituting these various transistors and an electrode thin film (capacitor element 69). (Not shown) and other metal thin films. In the laminated structure shown in FIG. 3, the scanning lines 3 and the data lines 6 are naturally constructed, but the illustration thereof is omitted.

  On the other hand, each of the aforementioned organic EL elements 8 includes a pixel electrode 13, a light emitting functional layer 18, and a counter electrode 5 among the above-described various elements constituting the laminated structure, as shown in FIG. 3.

Among these, the pixel electrodes 13 are formed on the element substrate 7 so as to be arranged in a matrix. The fact that the organic EL elements 8 are arranged in a matrix corresponds to the fact that the pixel electrodes 13 are arranged in a matrix like this (see FIGS. 1 and 3).
The pixel electrode 13 is electrically connected to the circuit element thin film 11 through the contact hole 360. Thereby, the pixel electrode 13 can apply a current supplied from the current supply line 113 to the light emitting functional layer 18 via the second transistor 9 shown in FIG. The contact hole 360 is formed so as to penetrate through the first and second interlayer insulating films 301 and 302.
Such a pixel electrode 13 is made of a translucent and conductive material such as ITO (Indium Tin Oxide).

As shown in FIG. 3, a partition wall (bank) 330 is formed in a region between adjacent pixel electrodes 13 in plan view. The actual height of the partition wall 330 in the vertical direction in the drawing is approximately 1 to 2 μm. The partition 330 plays a role of partitioning each organic EL element 8.
Such a partition 330 is preferably made of, for example, an insulating transparent resin material, particularly a material having liquid repellency (the reason will become clear later in the description of the film forming method). More specifically, for example, fluorine resin, or acrylic resin, epoxy resin, polyimide or the like can be used.
When the partition wall 330 is made of such various resin materials, the base layer may be made of an inorganic material such as SiO ₂ (that is, in this case, the partition wall 330 is on the lower layer side). It has a laminated structure of inorganic material and organic material on the upper layer side.) According to this, even when the pixel electrode 13 is made of ITO or the like as described above, the adhesion between the pixel electrode 13 and the partition wall 330 can be improved.

As shown in FIG. 3, the light emitting functional layer 18 is formed on the pixel electrode 13. The light emitting functional layer 18 includes at least an organic light emitting layer, and the organic light emitting layer is composed of an organic EL material that emits light by combining holes and electrons. In FIG. 3, the organic EL material is a polymer material and is formed by a film forming method described later. In this case, the organic EL material is supplied only in each space partitioned by the partition wall 330 (that is, for each pixel).
Thus, according to the aspect in which the organic EL material is supplied only to the space partitioned by the partition wall 330, the light emitting functional layer can be provided separately for each color. That is, for each space, for example, it is possible to form a light emitting functional layer including organic EL materials dedicated to red light, green light, and blue light.
As other layers constituting the light-emitting functional layer 18, part or all of an electron block layer, a hole injection layer, a hole transport layer, an electron transport layer, an electron injection layer, and a hole block layer may be provided.

The counter electrode 5 is in contact with the light emitting functional layer 18 of the plurality of organic EL elements 8. That is, the counter electrode 5 extends over the area of the light emitting functional layer 18 defined by the partition 330 and the partition 330 so as to be common to the plurality of pixel electrodes 13. The counter electrode 5 is formed in a rectangular shape in plan view (a so-called solid having no special opening, gap, or the like therein). The periphery of the counter electrode 5 is electrically connected to the power supply line 201 shown in FIG. 1 (the connection mode is not shown).
In this embodiment, the pixel electrode 13 is an anode and the counter electrode 5 is a cathode, but vice versa.
Such a counter electrode 5 may be made of a light-transmitting and conductive material such as ITO (Indium Tin Oxide), but in the case of FIG. 3, a metal having a relatively high light reflectance, such as aluminum, is used. It is made including. Thereby, the light emitted from the light emitting functional layer 18 is reflected by the lower surface of the counter electrode 5 in the drawing and proceeds to the side where the element substrate 7 exists. Thus, the organic EL device of this embodiment is a so-called bottom emission type. In the case where the counter electrode 5 is made of a light-transmitting material such as ITO, for example, a reflective layer may be provided separately on the lower layer side in the figure as viewed from the pixel electrode 13. In this case, the organic EL device is a so-called top emission type.

In the above configuration, when a current is passed between the pixel electrode 13 and the counter electrode 5, and simultaneously when a current is passed through the light emitting functional layer 18, the light emitting functional layer 18 emits light (already performed with reference to FIG. 2). See also explanation.) In addition, since the organic EL device of this embodiment is a bottom emission type, the element substrate 7 needs to be made from a translucent material. However, if the above-mentioned top emission type is adopted, the element substrate 7 may be made of an opaque material such as ceramics or metal. However, even in this case, there is no particular reason that it should not be a translucent material such as glass.
Further, as shown in FIG. 3, the structure of the laminated structure described above is formed so as to cover only the image display region 7a. Although a laminated structure is also formed in the peripheral region 93a, the laminated structure is different from that on the image display region 7a, and as shown in FIG. 3, the first and second interlayer insulating films 301 and 302, In addition, it has a structure including only a partition 332D formed as the same film as the partition 330. The partition wall 332D extends so as to border the outer contour of the element substrate 7.

  Hereinafter, a method for manufacturing the organic EL device as described above, in particular, a method for forming the light emitting functional layer 18 constituting the organic EL element 8 will be described.

<Substrate to which the film forming method of this embodiment is applied>
First, a substrate to which the film forming method of the present embodiment is applied, particularly its specific size and the like will be described.
In this embodiment, a glass substrate of 400 mm × 500 mm is prepared as a material for the element substrate 7. The element substrate 7 shown in FIG. 1 is included in this glass substrate as a chip having an outer shape of 50 mm × 40 mm.
More specifically, the element substrate 7 has the image display area 7a and the peripheral area 93a as described above. Of these, the image display area 7a has the organic EL elements 8 in a matrix as described above. Is defined as an area arranged in
Each of the organic EL elements 8 has a track shape in plan view as shown in FIG. Such a shape with rounded corners makes it possible to stably hold the ink in the inner region even though the ink supplied therein has surface tension. A partition region partitioning each of these organic EL elements 8 coincides with the above-described formation region of the partition wall 330.
Among such organic EL elements 8, the organic EL elements 8 arranged in the rightmost column in the drawing include a light emitting functional layer 18 containing an organic EL substance that emits blue light. Further, the organic EL elements 8 arranged in the left adjacent column have the light emitting functional layer 18 containing the organic EL substance that emits green light, and the organic EL elements 8 arranged further to the left of the organic EL element 8 emit light containing the organic EL substance that emits red light. Each of the functional layers 18 is provided. Hereinafter, blue, green, and red organic EL elements 8 are sequentially arranged.
Among the plurality of organic EL elements 8 arranged in this way, one set of three organic EL elements 8 for blue, green, and red constitutes a pixel G as shown in FIG. That is, one pixel G is configured with three pixels as a unit. Thus, in the present embodiment, the concept of “pixel” and the concept of pixel (that is, organic EL element 8) are properly used.
The “pixel” in the present embodiment corresponds to the “small region” in the present invention.

On the other hand, the peripheral area 93a is positioned so as to surround the periphery of the image display area 7a. Here, the present embodiment is particularly characterized in that the size of the peripheral region 93a is determined in advance as follows. That is, the distance WD shown in FIG. 4 satisfies the following expression.
WD = 3 · WP × SQR (10) (1)
Here, WP is the width of one organic EL element 8 in the horizontal direction in the drawing as shown in FIG. 4, and “SQR” represents the root sign.
Although the basis of this formula (1) will be described later, the peripheral region 93a in the present embodiment has a relatively small width (that is, the above-mentioned distance WD) determined based on this formula (1). This is defined as an area in which the strip has a border around the image display area 7a.

  Note that the width in the left-right direction of the organic EL element 8 shown in FIG. 4, that is, the pixel width WP, the width of the partition 330 between the organic EL elements 8 in the same direction, that is, the partition width WB, and the WD described above are In the form, they are 44 μm, 22 μm, and 417 μm (the last is obtained as 3 × 44 × SQR (10) from the above equation (1)). According to the former two, the pixel pitch between the organic EL elements 8 in the horizontal direction in the figure is 66 μm. The total number of organic EL elements 8 arranged in the image display area 7a is 176 RGB × 208.

  Now, the film forming method according to this embodiment is performed as follows on the element substrate 7 in which the size of the peripheral region 93a is determined as described above in relation to the image display region 7a.

<Steps until formation of partition wall 330>
First, the circuit element thin film 11, the insulating films 301 and 302, and the pixel electrode 13 are formed on the element substrate 7. In any of these film formations, a known film formation method such as a CVD (Chemical Vapor Deposition) method or a sputtering method, or a photolithography method is appropriately used. At that time, since the formation of the circuit element thin film 11 includes the manufacture of a TFT (Thin Film Transistor) such as the first transistor 68, a doping process or the like to the semiconductor layer is also performed, and the formation of the pixel electrode 13 is also performed. In the process, an appropriate etching process or the like is also performed in order to form the contact hole 360 in the insulating films 301 and 302.

Subsequently, as shown in FIG. 5, a partition wall 330 and a partition wall 332D are formed.
The outer shape of the partition wall 330 (element / partition wall) is formed through, for example, an exposure process and a development process after application of photosensitive polyimide. In the process of forming the element / partition, the partition 332D on the peripheral region 93a is also formed simultaneously as the same film as the element / partition.
Subsequently, the surface of the element / partition is given liquid repellency or ink repellency, for example, by subjecting the element / partition to an atmospheric pressure plasma treatment or the like. Here, the atmospheric pressure plasma treatment includes O ₂ —CF ₄ continuous plasma treatment and the like. In this case, for example, oxygen plasma treatment is preferably performed at atmospheric pressure, power of 300 W, electrode-substrate distance of 1 mm, oxygen gas flow rate of 100 ml / min, helium gas flow rate of 10 l / min, and then CF ₄ gas. CF ₄ plasma treatment is performed at a flow rate of 100 ml / min and a helium gas flow rate of 10 l / min. It should be noted that the time during which the element / partition is exposed to the plasma is preferably set to be relatively longer in the CF ₄ plasma treatment than in the oxygen plasma treatment.
As described above, the partition walls 330 and 332D are formed.

<Droplet coating process>
After the formation of the partition wall 330 is completed, the light emitting functional layer 18 is subsequently formed. In the present embodiment, an example in which the light emitting functional layer 18 including a hole injection layer and a light emitting layer is formed will be described. Both of the hole injection layer and the light emitting layer are formed by an ink jet method (droplet discharge method).

First, the hole injection layer 18P (see FIG. 8) is formed.
The material includes Bayer (registered trademark) of Bayer as a hole injection material, which is a polar solvent as a solvent, isopropyl alcohol, N-methylpyrrolidone, 1,3-dimethyl-2-imidazolidinone. The ink for forming a hole injection layer dispersed in the mixture is prepared. As shown in FIG. 6, the hole injection layer forming ink is ejected as droplets DR1 by the inkjet head IJH toward the space surrounded by the partition walls 330 on the pixel electrodes 13. The discharge process of the droplet DR1 is performed every pixel pitch of 66 μm described above.
When the droplet DR1 lands on the pixel electrode 13, as shown in FIG. 6, it becomes a droplet 18PD. Note that the use of these symbols “18PD” and “DR1” is merely used for convenience of explanation, and there is no essential difference between the droplets 18PD and DR1.
In such a droplet application process, both the droplet DR1 before landing and the droplet 18PD after landing behave so as to avoid the surface of the partition wall 330 having liquid repellency or ink repellency. As shown in FIG. 6, the droplet 18PD is suitably stored in an appropriate space (that is, a space surrounded by the partition wall 330).
For example, Epson's MJ-930C is preferably used as the ink jet head IJH used for discharging the droplet DR1 and the droplet DR2 described later.

On the other hand, the droplet DR2 discharge step is performed in parallel with the droplet DR1 discharge step. As shown in FIG. 6, this discharge process is performed such that the discharge is directed to the surface of the second interlayer insulating film 302 in the peripheral region 93a. Further, the droplet DR2 is composed only of the solvent constituting the hole injection layer forming ink.
When the droplet DR2 lands on the pixel electrode 13, a droplet 185PD is formed as shown in FIG. It should be noted that the proper use of the symbols “DR2” and “185PD” here is the same as the relationship with the droplets DR1 and 18PD described above. In other words, there is no essential difference between the two.

  Here, particularly in the present embodiment, it should be noted that the application of the droplet 185PD is performed only within the range defined by the distance WD described above. In addition, the present embodiment is also characterized in that the total mass of the droplet 185PD is adjusted to a constant value. Any of these points should be described with reference to a comparative example which will be described later with reference to FIGS. 9 and 10, and the description will be given at that time.

When the droplet discharge process as described above is completed, a state as shown in FIG. 7 appears on the element substrate 7. That is, in the image display region 7a, a plurality of droplets 18PD are provided for each space surrounded by the partition walls 330, and in the peripheral region 93a, the space on the second interlayer insulating film 302 surrounded by the partition walls 330 and 332D. It is said that a droplet 185PD is provided in If this is viewed in plan, the situation is such that the droplets 185PD surround the droplets 18PD arranged in a matrix (see FIG. 4; however, these droplets in FIG. Is not shown.)
As can be seen from the above, in this embodiment, the hole injection layer forming ink is applied for each organic EL element 8, that is, for each pixel. It is included in “applying for each small region” in the present invention. The application of the droplet 18PD may be performed simultaneously (simultaneously) for all or a part of the plurality of pixels occupying the image display region 7a, or more specifically, sequentially for each pixel. May be done. In the present invention, “applying for each small region...” Includes all of the above cases.

<Drying process (evaporation process)>
After the application of the droplets 18PD and 185PD is completed, a drying process for these is subsequently performed. Specifically, for example, in this drying process, first, in vacuum (1 torr (133.3 Pa)), after waiting for 20 minutes to elapse, after placing the substrate to be processed in the chamber at room temperature, secondly, In a nitrogen atmosphere, the process is performed including a step of performing a heat treatment for 10 minutes in an environment of 200 ° C. (a substrate to be processed is placed on a hot plate).
As a result, the solvent contained in the droplets 18PD and 185PD evaporates as shown in FIG. Regarding the droplet 18PD, after the solvent evaporates, the hole injection material as a solute still remains, but this becomes the hole injection layer 18P. On the other hand, since the droplet 185PD is made of only a solvent, in principle, nothing remains on the second interlayer insulating film 302 in the peripheral region 93a after the solvent evaporates.
During the drying process, the pixel G or pixel located relatively close to the boundary between the peripheral region 93a and the image display region 7a is helped by the relatively active evaporation of the droplet 185PD. There is no excessive acceleration of evaporation. That is, each pixel in the image display region 7a includes a hole injection layer 18P having a substantially same thickness (in other words, a hole injection layer 18P having substantially the same hole injection material). Become.

When the formation of the hole injection layer 18P is completed as described above, the light emitting layer is subsequently formed.
The formation process of the light emitting layer is basically the same as the formation process of the hole injection layer 18P described above. That is, in the light emitting layer forming step, the ink for forming the light emitting layer is ejected by the ink jet head IJH, whereby the ink applying step is performed, and thereafter, the ink is dried. Further, the former application step includes a step in which only the solvent constituting the light emitting layer forming ink is applied to the surface of the second interlayer insulating film 302 in the peripheral region 93a, and the latter drying step includes the solvent. (It is clear from this description that if these steps are illustrated, it will be drawn in the same manner as FIGS. 6 to 8 already referred to. (This is not shown to avoid duplication.)

  However, the material of the ink used in the coating process is naturally different in the formation process of the light emitting layer as compared with the formation process of the hole injection layer. That is, in the light emitting layer forming ink, for example, a polyfluorene-based material that emits red, green, and blue light is used as the organic EL material, and cyclohexylbenzene is used as the solvent. As a matter of course, the light emitting layer is not formed directly on the pixel electrode 13 but on the hole injection layer 18P.

As a result, the formation of the light emitting functional layer 18 is completed. After that, if the counter electrode 5 is formed by using a film forming method such as appropriate vapor deposition, the result is finally shown in FIG. The construction of the laminated structure will be completed.
The counter electrode 5 preferably contains aluminum or the like as described above, but more specifically includes, for example, a 2 nm LiF layer, a 20 nm Ca layer, and a 200 nm Al layer.
Further, in order to ensure proper driving of the organic EL device, it is possible to incorporate new elements even after the counter electrode 5 is formed. For example, a sealing film for suppressing the ingress of moisture and oxygen into the light emitting functional layer 18 is provided on the counter electrode 5, or the sealing film of the sealing film is secured to ensure the flatness of the sealing film. It is possible to provide a planarizing film formed as a base film.

According to the method for manufacturing an organic EL device as described above, in particular, the method for forming the light emitting functional layer 18 constituting the organic EL element 8, the following effects can be obtained.
That is, in this embodiment, since the size of the peripheral region 93a of the element substrate 7 is defined by the distance WD described above, the peripheral region 93a can be narrowed, that is, the frame can be narrowed. Such an effect can be understood more clearly by comparison with the comparative example shown in FIGS.

9 and FIG. 10 show conventional organic EL materials or the like possessed by the organic EL element 8 located near the boundary between the image display region 7a and the peripheral region 95a (in addition to the above-mentioned “organic EL material”, “hole injection”). In order to prevent a decrease in the amount of “material”, etc., hereinafter simply referred to as “functional substance” as compared with that of the other organic EL elements 8, as a dummy around the image display region 7 a. The present invention relates to a technology including an organic EL element (hereinafter referred to as “dummy element”) 8D. 9 and 10 correspond to FIGS. 3 and 4 as far as the purpose is concerned.
As shown in FIGS. 9 and 10, the dummy element 8D has almost the same structure as the structure of the organic EL element 8 provided in the image display region 7a. If such a dummy element 8D is provided, as already described in the above [Problems to be Solved by the Invention], the evaporation promotion phenomenon occurring in the peripheral portion occurs in the formation region of these dummy elements 8D. Thus, excessive evaporation of the organic EL element 8 in the image display region 7a is avoided, and as a result, all of the organic EL elements 8 can include substantially the same amount of functional substance.
However, in order to appropriately avoid the influence of such an evaporation promotion phenomenon, it is important how to set the amount of the solvent that takes over the phenomenon. In other words, while expecting the above-described evaporation promotion phenomenon, a suitable time point when it is completed (that is, when the whole amount of the solvent on the peripheral region 95a evaporates) and all the organic EL elements 8 in the image display region 7a. The point in time when the evaporation is complete must be almost simultaneously. If not (that is, if the evaporation promotion phenomenon in the peripheral area 95a is completed but the evaporation in the image display area 7a is not completed), the evaporation promotion phenomenon eventually occurs in the image display area 7a. This is because the significance of providing the dummy element 8D is lost (the evaporation promoting phenomenon here can also occur in the peripheral portion inside one pixel. As a result, there is a phenomenon that there are many functional substances in the center of the pixel and few in the periphery.)

  Therefore, conventionally, in order to suitably adjust the amount of such a solvent, the “number” of the dummy elements 8D has been adjusted. FIG. 10 shows an example of this, but assuming the above specific numerical examples (ie, WP, WB, number of pixels, etc.) relating to the present embodiment, the number is about 10 in number. Preferred. That is, as shown in the figure, if ten dummy pixels 8D are arranged on the peripheral region 95a so as to be connected to a certain pixel G, the evaporation promotion phenomenon is retained in the dummy pixels 8D. The solvent (refer to the droplet 18PD-D surrounded by the partition wall 330D in the drawing) is assumed, and when the phenomenon in the area is completed, the organic EL element 8 in the image display area 7a is dried. (In FIG. 10, only one column of dummy pixels 8D is shown. Actually, the dummy pixels 8D are arranged over the entire surface of the peripheral region 95a. Also, the volume of the droplet 18PD-D and the volume of the droplet 18PD may be considered equal.)

  However, arranging such a relatively large number of dummy pixels 8D requires a relatively large peripheral area 95a, as is apparent from FIG. Actually, according to the above specific numerical example, since the pixel pitch is 66 μm, the distance WDD shown in FIG. 10 is 66 × 3 × 10≈1.98 mm (where “10” is the number of pixels). End up.

However, in the present embodiment, such a problem that the peripheral area is enlarged is avoided. The above-described equation (1) is one solution for that.
WD = 3 · WP × SQR (10) (1) (repost)
In this equation (1), the numerical value “10” in the root sign is based on the number of the preferred dummy elements 8D arranged (that is, 10). Including this, equation (1) is further based on the grounds as represented in FIG.

First, in FIG. 11, each of a plurality of substantially semicircular shapes shown in the lower stage expresses the droplet 18PD-D held in the dummy element 8D shown in FIG. Moreover, the substantially semicircular shape shown in the upper stage expresses the droplet 185PD shown in FIG. Here, a certain substantially semicircular shape shown in the lower part of FIG. 11 is based on a comparison between FIG. 9 and FIG. 11, or because the size of each pixel is considerably small. The shape of the droplet 18PD-D on the element substrate 7 can be considered as it is expressed as it is (that is, both shapes are almost the same). This can also be said in relation to the substantially half shape shown in the upper part of FIG. 11 and the shape of the droplet 185PD on the element substrate 7.
Therefore, the substantially semicircular shape shown in the upper part of FIG. 11 is the “droplet 185PD” as it is, and the substantially semicircular shape shown in the lower part thereof is the “droplet 18PD-D” as it is. Each can be called.
Since these droplets 185PD and 18PD-D shown in FIG. 11 are droplets made of the same solvent, a substantially similar relationship is established between these two shapes. Further, the cross-sectional area of the liquid droplet 185PD shown in FIG. 11 represents the volume of the liquid 185PD, and the cross-sectional area of the liquid droplet 18PD-D shown in FIG. 11 represents the volume of the liquid 18PD-D. be able to.

Based on FIG. 11, the most basic idea in the present embodiment is that the volume (or mass) of the droplet 185PD in the upper part of the figure is the total volume of all droplets 185PD-D in the lower part of the figure ( Alternatively, it is intended to match the total mass). According to this, even when the dummy element 8D is not provided as in the present embodiment, the amount of solvent retained when the dummy element 8D is provided, that is, the amount of solvent that can bear the above-described evaporation promotion phenomenon is ensured. It will be. “=” Shown in FIG. 11 represents this.
Actually, the amount of the droplets DR2 or 185PD applied to the peripheral region 93a in the above-described <Droplet application step> is determined according to the above concept. Incidentally, in FIG. 4, FIG. 6, or FIG. 7, the hole injection layer forming ink ejected per pixel is 110 ng, and in that case, the region R2 which is a part of the peripheral region 93a of FIG. (This corresponds to the “second region” in the present invention.) The solvent of the ink ejected in the range indicated as 3.3 mg is 3.3 mg. In addition, the light emitting layer forming ink discharged per pixel is 100 ng, and the solvent of the ink discharged in the range shown as the region R2 in that case is 3.0 mg. Of course, this is just an example.

Subsequently, on the basis of such a basic idea, the solvent having the amount obtained as described above does not provide the partition 330D (see FIGS. 9 and 10) provided when the dummy elements 8D are arranged. In this case, it is estimated how much area can be applied if the area can be secured. That is, from the viewpoint of FIG. 11, the size of the length L1 shown in the figure is estimated.
For this purpose, the droplet 185PD and the droplet 18PD-D are substantially similar to each other, and the sectional area of the droplet 185PD or 18PD-D is approximately proportional to the square of the length L1 or L2 shown in FIG. Is done. From the above, it can be seen that the length L1 is proportional to the square root of the length L2 shown in FIG. The square root of the length L2 can be considered to be proportional to the number of dummy elements 8D or the square root of the number of pixels including three of these dummy elements 8D.
The above is the basis of “SQR (10)” in the formula (1), and further the basis of the formula (1) itself.

In this way, in this embodiment, if the peripheral region 93a defined by the distance WD is secured, the same amount of solvent as that in the case of providing the dummy element 8D can be secured, and accordingly, in the image display region 7a. It becomes possible to make the amount of the functional material finally held by the organic EL element 8 substantially the same.
In spite of this, in this embodiment, as clearly shown in FIG. 4 and FIG. 10 again, the extremely effective narrowing of the peripheral region (from “95a” in FIG. 10 to “93a in FIG. 4”). (Or numerically, from 1.98 mm to 417 μm as described above) is achieved.

  In the above description, the focus is mainly on the “volume” of the droplet, but the same reasoning as described above can be realized even if the “surface area” is focused. That is, if the surface area of the droplet 185PD is made to coincide with the total surface area of all the droplets 18PD-D, an evaporation process substantially similar to the evaporation process according to the latter can be realized in the former. Even in this case, since the mass can be obtained based on the surface area of the droplet 185PD determined as described above, the same effect as described above can be obtained after all.

  In addition to the above, the manufacturing method or the film forming method according to the present embodiment also has the following effects. That is, in the present embodiment, since the droplet 185PD contains only the solvent for the hole injection layer forming ink as described above, almost all of the droplet 185PD is evaporated after the drying process is completed as shown in FIG. Resulting in. Therefore, the region where the droplet 185PD once existed can be effectively used as a region equipped with various elements for suitably operating the organic EL device. FIG. 1 referred to at the beginning can be seen as one example of this effective use. That is, in FIG. 1, the scanning line driving circuits 103A and 103B, the data line driving circuit 106, the precharge circuit 106A, and the power supply line 201 are provided around the image display area 7a. The surrounding area is nothing but the peripheral area 93a shown in FIG.

  In the above description, in order to match the reference numerals used in FIG. 7 and the like, for convenience of explanation, the droplet 18PD containing the hole injection layer forming ink and the droplet 185PD containing the solvent are taken into consideration. However, the above description also applies to droplets containing the light emitting layer forming ink and droplets containing the solvent. Needless to say.

Although the embodiments according to the present invention have been described above, the film forming method according to the present invention is not limited to the above-described embodiments, and can be applied to various modifications.
(1) In the embodiment described above, the partition wall 332D as the same film as the partition wall 330 is formed in the peripheral region 93a, and in the space surrounded by the partition walls 330 and 332D and on the second interlayer insulating film 302 However, the film forming method according to the present invention can be applied to cases other than such a case.
For example, as shown in FIG. 12, it is possible to adopt a form in which the third interlayer insulating film 331 is provided as the same film as the partition 330 instead of providing the partition 332D in the peripheral region 93a. However, compared with such a case, the above embodiment is advantageous in that the liquid droplets applied to the peripheral region 93a can be held relatively stably (see FIGS. 12 and 7). It is clear when compared to the comparison.)

(2) Alternatively, as shown in FIGS. 13 and 14, in addition to the partition wall 332D, the partition wall divides the peripheral region 93a into small regions having appropriate sizes, as shown in FIGS. A form in which 333D is provided can also be adopted. According to this, since the droplets applied to the peripheral region 93a are applied to the region surrounded by the partition walls 332D and 333D and the outermost partition wall 330, the droplets are larger than those in FIG. It is possible to obtain the advantage that the holding is stable.
As can be seen from FIG. 13, in this case, the movement of the droplets applied to each small region in the peripheral region 93a becomes more difficult. For example, even if the element substrate 7 is tilted, the liquid It does not occur that the droplet is biased to a part of the element substrate 7 (in the case of FIG. 12, such a case may also occur). Therefore, in the above-described <evaporation step>, it is possible to uniformly evaporate all of the droplets 18PD, and thus holding all the organic EL elements 8 in the image display region 7a with substantially the same amount of functional substance. More effectively.

(3) In the above-described embodiment, the film forming method is described in which the droplets 18PD are applied to all the organic EL elements 8 in the image display region 7a all at once, and the droplets 18PD are evaporated all at once. The present invention is not limited to such a form. For example, in some cases, first, the coating process and the evaporation process are performed only for the blue and green organic EL elements 8, and second, the coating process and the evaporation process are performed for the remaining red organic EL elements 8. You may perform the film-forming method of performing. According to this, the amount of the solvent in the solution containing the functional substance evaporated in each of the first and second sets is smaller than that in the above-described embodiment. Then, in this case, the amount of the solvent to be applied to the peripheral region, which is necessary for the organic EL elements 8 in the image display region 7a to be provided with substantially the same amount of the functional substance, becomes at least better. Therefore, the peripheral region can be further narrowed in addition to the above.
For example, in the above example, the amount of solvent that can correspond to the evaporation step for the two-color organic EL element 8 only needs to be ensured, so that the above equation (1) is, for example,
WD = 2 · WP × SQR (10) (1 ′)
Can be rewritten. In other words, according to this example, it is possible to further reduce the size of the peripheral area to 2/3 of the above embodiment as a reference.

(4) In the above-described embodiment, the example in which the droplet 18PD in the image display region 7a and the droplet 185PD in the peripheral region 93a are applied simultaneously has been described, but the present invention is not limited to such a form. . For example, depending on circumstances, the droplet 185PD may be performed first and the droplet 18PD may be performed later, or vice versa.
The order of the coating process relating to the image display area 7a (hereinafter referred to as “first process”) and that relating to the peripheral area 93a (hereinafter referred to as “second process”) is based on the nature of the solvent used. It should be done. For example, if the boiling point of the solvent is 200 ° C. or higher, the first step and the second step are carried out simultaneously, and if it is below 200 ° C., the second step is carried out first, and the first step is carried out later. It seems. The reason why the second step is performed first when the boiling point of the solvent is relatively low is that the spontaneous evaporation of the solvent is likely to be promoted in such a case, and thus an evaporation phenomenon that may occur even during the first step. It is because it becomes possible to make uniform.
Incidentally, in the above embodiment, the boiling points of N-methylpyrrolidone and 1,3-dimethyl-2-imidazolidinone, which are used as the solvent for the hole injection layer forming ink, are 202 ° C. and 225.5 ° C., respectively. Therefore, there is no particular problem even if the first step and the second step are performed simultaneously (note that the boiling point of isopropyl alcohol is 82.4 ° C., but in this case, the solvent is used as a mixture thereof) So no big problems will arise.) Rather, in this case, it is possible to enjoy cost reduction by reducing the number of processes by simultaneously performing the same coating process. The same applies to cyclohexylbenzene having a boiling point of 239 ° C., which is used as a solvent for the light emitting layer forming ink.

(5) In the above-described embodiment, the organic EL element 8 in a plan view is assumed to have a track shape (see FIG. 4), but the present invention is not limited to such a form. Other than that, for example, it may be circular, elliptical, square, rectangular, or the like. However, for the reasons already described (stable ink retention), a shape as if the corners are rounded is preferable to a shape having corners.
(6) Or, in relation to this, in the above-described embodiment, it is assumed that all the organic EL elements 8 have the same shape, but the present invention is not limited to such a form. For example, as shown in FIG. 15, the pixel width Wb of the organic EL element 8 ′ for blue is 58 μm, the pixel width Wg of the organic EL element 8 ′ for green is 30 μm, and the pixel of the organic EL element 8 ′ for red is used. The pixels for each color may have different shapes, such as a width of 44 μm, with different widths.
In this case, the equation (1) is rewritten as follows.
WD = (Wr + Wg + Wb) × SQR (10) (1 ″)
Further, the hole injection layer forming ink ejected to the blue, green, and red pixels is 145 ng, 75 ng, and 110 ng, and the region R2 that is a part of the peripheral region 93a in FIG. The solvent of the ink ejected in the range indicated as “(this corresponds to the“ second region ”in the present invention) is 3.3 mg.
On the other hand, regarding the light emitting layer forming ink, 132 ng (for blue), 68 ng (for green), and 100 ng (for red) are similarly ejected in the range indicated as the region R2 ′ in that case. The ink solvent is 3.0 mg.
The above is, of course, only an example.

(7) In further relation, in the above-described embodiment, the partition wall 330 is formed between all the organic EL elements 8, and each of these organic EL elements 8 is separated. The invention is not limited to such forms. For example, as shown in FIG. 16, in contrast to FIG. 4 and the like, an organic EL element 81 having a length twice as large as the vertical direction in the figure is formed, and a bank 335 corresponding to this is formed. It may be a form. Moreover, you may form a partition so that the organic EL element located in a line with an up-down direction may be connected.

(8) Further, in the above-described embodiment, an example in which three pixels (that is, the organic EL element 8) configure one pixel G as illustrated in FIG. The present invention is not limited to this. For example, in some cases, fewer than three pixels may constitute a single pixel, or a larger number of pixels may constitute a single pixel. As an example of the former, for example, the case where all organic EL elements include only an organic EL substance that emits the same color and one organic EL element constitutes one pixel is considered, and as the latter example, for example, RGB In addition, an organic EL element containing an organic EL substance that emits white light is provided, and one set of these four organic EL elements constitutes one pixel.

(9) During the description of the above-described embodiment or the modification example just described, the size of the peripheral region 93a on the element substrate 7 is determined by the above formula (1), formula (1 ′), and formula (1 ″). However, the present invention does not require the WD value itself to be strictly adhered to. In short, since it is a problem whether uniform evaporation regarding all the organic EL elements 8 in the image display region 7a is realized or not, according to various situations and the like, appropriate adjustment based on the WD, that is, WD ± α, Adjustment by “α” or the like can be made. However, in this case, if this α becomes too small, it becomes impossible to secure a sufficient amount of solvent on the peripheral region, and if it becomes too large (especially, it will reach “WDD” shown in FIG. 10). If α becomes such, the achievement of the objective of narrowing the peripheral area is hindered.
From the above viewpoint, the value WDr to be actually protected in the present invention is:
0.8WD ≦ WDr ≦ 2WD
(That is, WDr ranges from 80% to 200% based on WD determined by the above formula (1), formula (1 ′), and formula (1 ″)). Preferably within.)

(10) Although the above-described embodiment describes an example in which the film forming method according to the present invention is applied to the organic EL device, particularly the light emitting functional layer 18 of the organic EL element 8 which is a constituent element thereof, the present invention is described. Is not limited to such a form. The present invention can also be applied to, for example, a color filter for an organic EL device or a liquid crystal display device.
In this case, pigments (organic pigments or inorganic pigments), dyes, natural pigments, or the like are used as materials (corresponding to “functional substances” in the present invention) that cause the color filter to be colored. More specifically, for example, organic pigments include compounds classified as Pigment in the Color Index (CI; issued by The Society of Dyers and Colorists), and more specifically, C.I. I. Pigment Yellow 1, 3, 12, etc., C.I. I. Pigment orange 1, 5, 13 etc., C.I. I. Pigment red 1, 2, 3, etc., C.I. I. Pigment Blue 15, 15: 3, 15: 4, etc. are preferable. These organic pigments can be used alone or in admixture of two or more. Alternatively, inorganic pigments include, for example, titanium oxide, barium sulfate, calcium carbonate, zinc white, lead sulfate, yellow lead, zinc yellow, red bean (red iron (III) oxide), cadmium red, ultramarine blue, bitumen, and chromium oxide. Examples include green, cobalt green, amber, titanium black, synthetic iron black, and carbon black.
Furthermore, in this case, as the solvent, for example, a diethylene glycol dialkyl ether solvent (= relatively high boiling point) or the like, or ethylene glycol monoalkyl ethers such as ethylene glycol monomethyl ether and ethylene glycol monoethyl ether (= relatively low boiling point) Etc.

<Application>
Next, an electronic apparatus to which the organic EL device according to the present invention is applied will be described. FIG. 17 is a perspective view showing a configuration of a mobile personal computer using the organic EL device according to the above-described embodiment as an image display device. The personal computer 2000 includes an organic EL device as a display device and a main body 2010. The main body 2010 is provided with a power switch 2001 and a keyboard 2002.
FIG. 18 shows a mobile phone to which the organic EL device according to the above embodiment is applied. A cellular phone 3000 includes a plurality of operation buttons 3001, scroll buttons 3002, and the organic EL device 1 as a display device. By operating the scroll button 3002, the screen displayed on the organic EL device is scrolled.
FIG. 19 shows an information portable terminal (PDA: Personal Digital Assistant) to which the organic EL device according to the embodiment is applied. The information portable terminal 4000 includes a plurality of operation buttons 4001, a power switch 4002, and an organic EL device as a display device. When the power switch 4002 is operated, various types of information such as an address book and a schedule book are displayed on the organic EL device.

  Electronic devices to which the organic EL device according to the embodiment is applied include those shown in FIGS. 17 to 19, digital still camera, television, video camera, car navigation device, pager, electronic notebook, electronic paper, calculator , A word processor, a workstation, a videophone, a POS terminal, a video player, a device equipped with a touch panel, and the like.

It is a top view which shows schematic structure of the organic EL apparatus which concerns on this embodiment of this invention. It is a circuit diagram which shows the detail of the unit circuit P of FIG. FIG. 2 is a cross-sectional view of a suitable fracture surface of the organic EL device shown in FIG. 1, particularly based on a fracture surface selected to include a boundary between the image display region 7 a and the peripheral region 93 a. FIG. 2 is a partially enlarged plan view of the organic EL device shown in FIG. 1. FIG. 4 is a sectional view having the same concept as in FIG. 3 and illustrating a method for manufacturing an organic EL device (from circuit element thin film 11 film formation to pixel electrode 13 film formation). FIG. 6 is a view (droplet discharge step) illustrating a method for manufacturing the organic EL device, following FIG. 5. FIG. 7 is a diagram illustrating a method for manufacturing the organic EL device (at the time of completion of the droplet discharge process), following FIG. 6. FIG. 8 is a diagram (drying process) illustrating the method for manufacturing the organic EL device, following FIG. 7. FIG. 4 is a cross-sectional view having the same concept as in FIG. 3 and showing an example in which a dummy element 8D is provided in a peripheral region 93a. FIG. 5 is a partially enlarged plan view having the same concept as in FIG. 4 and showing an example in which a dummy element 8D is provided in a peripheral region 93a. It is a conceptual diagram for demonstrating the basis of the distance WD which determines the magnitude | size of the peripheral region 93a which concerns on this embodiment. FIG. 4 is a cross-sectional view having the same concept as in FIG. 3, and is a diagram according to a modification in which a partition wall 332 </ b> D is provided in contrast to FIG. 3. FIG. 5 is a partially enlarged plan view having the same concept as in FIG. 4, and is a diagram according to a modified example that is different from FIG. 4 in that partition walls 332 </ b> D and 333 </ b> D are provided. FIG. 4 is a cross-sectional view having the same concept as in FIG. 3, and is a diagram according to a modified example that is different from FIG. 3 in that partition walls 332 </ b> D and 333 </ b> D are provided. FIG. 5 is a partially enlarged plan view having the same concept as in FIG. 4, and is a diagram according to a modification in which the size of each organic EL element 8 is different from that in FIG. 4. FIG. 5 is a partially enlarged plan view having the same concept as in FIG. 4, and is a diagram according to a modification in which an organic EL element 81 is provided in contrast to FIG. 4. It is a perspective view which shows the electronic device to which the organic electroluminescent apparatus which concerns on this invention is applied. It is a perspective view which shows the other electronic device to which the organic EL apparatus which concerns on this invention is applied. It is a perspective view which shows the further another electronic device to which the organic EL apparatus which concerns on this invention is applied.

Explanation of symbols

7: Element substrate, 7a: Image display area, 93a: Peripheral area, G: Pixel, 8: Organic EL element, 13: Pixel electrode, 18: Light emitting functional layer, 5: Counter electrode, DESCRIPTION OF SYMBOLS 11 ... Circuit element thin film, 301 ... 1st interlayer insulation film, 302 ... 2nd interlayer insulation film, 330, 332D, 333D ... Partition, 331 ... 3rd interlayer insulation film, 8D ... Dummy element, 330D ...... Partition walls, DR1, 18PD ... (including solute) droplets, DR2, 185PD, 18PD-D ... (including solvent only) droplets, 18P ... Hole injection layers 103A, 103B ... Scanning line drive circuit , 106... Data line drive circuit, 106 A... Precharge circuit, 201.

Claims (6)

A first application step of applying a first material containing a solute containing a functional substance and a solvent for each of the first areas on the substrate and for each of the small areas dividing the first area into a predetermined number;
The second material containing at least the solvent of the same material, and a second coating step of coating before Symbol second region surrounding the first region on the substrate,
An evaporation step of evaporating both the solvent in the first material and the material in the second material;
With
In addition to the small area inside the first area,
A partition area that partitions between adjacent small areas among these small areas,
One small area and one partition area constitute one unit area,
The width of the second region in the second application step is
A total width of the small regions in the first region;
In the case where the second material applied to the outer small area of the outer one unit area including the outer small area and the outer partition area having the same arrangement structure as the one unit area is evaporated in the second area. The time point when the total amount of the second material applied to the small area outside the region evaporates is set to be substantially the same as the time point when the total amount of the first material applied to the small region of the first region evaporates. The square root of the number of subregions to be
The film forming method is set based on the product of The second material is
The film forming method according to claim 1 , wherein a region surrounding the first region is applied to a space surrounded by a partition wall that is divided into a predetermined number of regions. The second material includes the solvent and does not include the solute.
The film forming method according to claim 1 or 2, characterized in that. The second application step is performed before the first application step;
The film deposition method according to any one of claims 1 to 3, characterized in that. The second application step is performed simultaneously with the first application step.
The film deposition method according to any one of claims 1 to 3, characterized in that. The total number of the small areas dividing the first area is grouped into a plurality of small areas,
The first application step includes
Applying the first material to each of the plurality of small region groups;
The evaporation step includes
Implemented individually to correspond to each of the plurality of small region groups,
The film deposition method according to any one of claims 1 to 5, characterized in that.

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