JP4686063B2 - Image display panel - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image display panel using a film-like display element such as organic electroluminescence or liquid crystal.
[0002]
[Prior art]
A display element using organic electroluminescence (hereinafter simply referred to as “organic EL”) uses, for example, a polymer (plastic) film such as polycarbonate or polyethersulfone as a transparent substrate, and a transparent film serving as an anode is formed on the transparent substrate. An electrode, an organic functional layer, and a metal electrode for a cathode are sequentially laminated. Here, the organic functional layer is a single layer structure of only the light emitting layer, or a three layer structure of an organic hole transport layer and a light emitting layer and an organic electron transport layer, or a two layer structure of an organic hole transport layer and a light emitting layer, Refers to a laminate having a structure in which an electron or hole injection layer or a carrier block layer is inserted between these appropriate layers.
[0003]
An organic EL element having light emitting cells of so-called three primary colors of red (hereinafter simply referred to as “R”), green (hereinafter simply referred to as “G”) and blue (hereinafter simply referred to as “B”) is described above. A full color display using an organic EL can be configured by arranging these light emitting cells in a matrix on a transparent substrate. An important process at the time of manufacturing such an organic EL full color display is a process in which R, G, and B light emitting cells of the organic EL are separately applied by masking or the like. This is because the positional deviation accuracy of each R, G, B light emitting cell has been strictly demanded along with the high definition of full color display pixels.
[0004]
On the other hand, since organic materials used for organic EL dislike moisture, acid, alkali, etc., so-called wet processes such as etching using these solutions cannot be used in mask processing. For this reason, in the mask processing of the organic functional layer, a so-called dry process using a technique such as vapor deposition under a high temperature or high pressure environment is generally used.
[0005]
However, in a plastic film used as a transparent substrate for organic EL, expansion / contraction due to thermal stress such as heating / cooling appears remarkably. Therefore, in order to manufacture a full color display using an organic EL using such a plastic film as a transparent substrate, it is necessary to position each of the R, G, B light emitting cells by a highly accurate layering or film forming technique. For this reason, the complexity of the manufacturing process in the dry process at the time of manufacturing an organic EL full-color display panel and the increase in manufacturing cost have been problems.
[0006]
[Problems to be solved by the invention]
The present invention has been made to solve such a problem, and an object of the present invention is to provide a plastic transparent substrate for an organic EL display panel that has very little expansion / contraction due to thermal stress.
[0007]
[Means for Solving the Problems]
The present invention is an image display panel including an image display light emitting layer including a plurality of light emitting cells and a transparent substrate supporting the image display light emitting layer, including an insulating partition that separates each of the light emitting cells, The transparent substrate is made of a plastic layer, and a restraining member having a thermal expansion coefficient lower than that of the plastic layer is embedded in at least a part of the plastic layer below the insulating partition wall .
[0008]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of a transparent substrate for an organic EL display element according to the present invention is shown in the structural diagram of FIG.
In FIG. 1, the substrate 10 of the transparent substrate is a plastic film having flexibility such as polycarbonate, polyethersulfone, or acrylic as described above. In the present embodiment, lattice-shaped concave portions are formed on both surfaces of the plastic film (or only on one surface on which the organic EL layer is formed) by, for example, molding.
[0009]
The mesh member 20 is formed using a polymer material such as polyester having a lower coefficient of thermal expansion than the base material 10, and the dimensions of the mesh member 20 are the dimensions of the recesses provided in the base material 10. Match. In the present embodiment, the transparent member for the organic EL display element is realized by fitting and embedding the mesh member 20 in the concave portion of the base material 10.
[0010]
Note that the transparent substrate according to the present embodiment may be formed by forming a material having a low thermal expansion coefficient, such as silicon oxide (SiO 2), in the concave portion of the base material 10 by a process such as vapor deposition.
Incidentally, FIG. 1A is a plan view of a transparent substrate based on this embodiment, FIG. 1B is a cross-sectional view of the transparent substrate viewed from the AA ′ direction, and FIG. Sectional drawing seen from the BB 'direction is represented.
[0011]
An example of a method for manufacturing a transparent substrate based on the present embodiment is as follows.
First, at least the organic EL layer forming surface of the substrate 10 of the transparent substrate is provided with a lattice-shaped recess by a molding method using a mold or the like.
Next, in order to prevent scratches on the surface of the transparent substrate and to improve adhesion to inorganic substances, a hard coat layer such as an epoxy resin, an acrylic resin, a urethane resin, or the like is formed. Alternatively, such a hard coat layer may be formed by depositing SiO2 on the substrate surface.
[0012]
Subsequently, in order to increase the contrast with the organic EL light emitting unit, a black pigment such as chromium oxide or copper oxide may be applied to at least the bottom surface in the recess of the base material 10. For the same purpose, a black pigment may be mixed into the mesh member 20 to be described later, or the black pigment may be applied to the surface of the mesh member 20.
Further, a desiccant may be sprayed or applied in the recesses of the transparent substrate in order to achieve moisture-proof treatment of the transparent substrate, or the net member 20 may be mixed with the desiccant and molded.
[0013]
Next, the mesh member 20 formed of a low thermal expansion material is embedded in the recess and pressed with a press to fit the substrate 10. Furthermore, heat treatment is applied to the entire transparent substrate in order to improve the adhesion between both members. Instead of fitting and pressing the mesh member 20 formed of a separate member into the recess of the base material 10, as described above, for example, a low thermal expansion material such as SiO2 is applied by vapor deposition or by applying and baking. The film member 20 may be formed into a film in the recess of the substrate 10.
[0014]
Subsequently, a protective film such as silicon nitride oxide (SiON) is formed on the surface of the completed substrate, and external light is reflected on the surface of the transparent substrate opposite to the organic EL light emitting layer. An AR (Anti-Reflection) film is formed. By providing such an AR film film, it is possible to reduce the reflectance of external light and improve the visibility of the display screen. The AR film may be formed by vapor deposition of SiO 2 or TiO 2 (titanium oxide), printing, or thin film coating.
[0015]
A normal organic EL light emitting layer generation process is performed on the transparent substrate completed through the above manufacturing steps.
As described above, in the transparent substrate based on the present embodiment, the reticulate member 20 having a low thermal expansion coefficient is fitted and embedded in the base material 10 made of a normal plastic film, and both members are closely formed. ing. For this reason, even when thermal stress is applied to the transparent substrate in the production process of the organic EL light emitting layer, the base material 10 of the transparent substrate is constrained by the mesh member 20, and expansion and contraction of the entire transparent substrate can be reduced. . Therefore, it is possible to accurately and easily position the organic EL light emitting cell generated on the transparent substrate.
[0016]
Incidentally, in order to verify the effect of this example, an acrylic plate (277x477x3 mm) having a thermal expansion coefficient of 7 × 10 ⁻⁵ / ° K is used as a plastic film substrate, and the thermal expansion coefficient is 2 × 10 ⁻⁵ / ° K. An experiment was conducted by forming a polyester material having a diameter of 30 μm into a mesh member of 90 mesh / inch and embedding it in the surface layer of the film substrate. In the experiment, the film base material in which the mesh member was embedded and the film base material to which no processing was applied were heated from 20 ° C. to 90 ° C. in a thermostatic bath, and after 15 minutes, The expansion / contraction rate was measured. As a result, a reduction effect of about 26% in the expansion / contraction rate was observed in the film base material in which the mesh member was embedded compared to the unprocessed film base material.
[0017]
In other words, when patterning a light-emitting film for a display that requires vapor deposition at a certain high temperature, the positional deviation of the patterning of the light-emitting cells can be effectively reduced by using the film substrate according to this embodiment. Can do.
In addition, each part dimension of the mesh member 20 and parameters, such as the area ratio of the base material 10 and the mesh member 20 on a transparent substrate, are not limited to the Example shown in FIG. It goes without saying that various values can be taken depending on various factors such as the subsequent generation process of the organic EL light emitting layer.
[0018]
In the present embodiment, the net members 20 are arranged on both surfaces of the base material 10 of the transparent substrate. However, such treatment may be performed only on at least one surface on which the organic EL light emitting layer is generated.
Moreover, the recessed part provided in the base material 10 is not limited to a right-angled lattice, For example, a rhombus lattice may be sufficient. Further, depending on the stretching characteristics of the base material 10 used as the transparent substrate, the shape of the concave portion is not a lattice shape, and for example, it may be provided as a stripe shape in a direction that suppresses expansion and contraction in the stretching direction. Furthermore, it is good also as a structure which provides curvilinear recessed parts, such as a helical curve and a sine curve. In addition, it goes without saying that the shape of the constraining member embedded in the concave portion of the base material also becomes a rhombus lattice net shape or a simple belt shape.
[0019]
Next, an example of a full color display using organic EL light emitting elements in which R, G and B organic EL light emitting cells are provided in a matrix on a transparent substrate based on this embodiment is shown in the structural diagram of FIG. . FIG. 2 shows an organic EL light emitting cell formed on a portion made of a normal plastic film in the transparent substrate shown in FIG.
Note that the matrix arrangement of the R, G, and B organic EL light emitting cells shown in FIG. 2 is merely an example, and the arrangement of the organic light emitting cells according to this embodiment is not limited to the structure shown in FIG. In FIG. 2, the lattice of the mesh member 20 is provided for each of the R, G, and B cells. However, the present embodiment is not limited to this. For example, a plurality of R, G, and B You may provide the grid | lattice of the mesh member 20 so that the division of B light emitting cell may be included.
[0020]
Next, FIG. 3 shows a cross-sectional structure of the transparent substrate and the organic EL light emitting cell in the organic EL display panel of FIG.
In FIG. 3, the transparent substrate is composed of the base material 10 and the mesh member 20 as described above, and the protective film 30 made of SiO 2 or the like is formed on the upper surface thereof. An anode electrode 40 that is a transparent electrode, an organic EL light emitting layer 50, and a cathode electrode 60 that is a metal electrode are formed on the substrate. In addition, in order to separate each organic EL light emitting cell, an insulating partition 70 made of, for example, SiO 2 is provided for each cell.
[0021]
When the inner surface of the mesh member 20 or the concave portion of the base material 10 is colored black or the like, the position of the mesh member 20 as shown in FIG. 3 is prevented so as not to disturb the light emission from the organic EL light emitting layer 50. Is provided under the insulating partition 70 which is a non-light-emitting portion. However, even when the mesh member 20 is made of a transparent material such as SiO 2 and the concave portions of the base material 10 are not colored, the mesh member 20 is desirably provided under the insulating partition wall 70.
[0022]
The reason is that even if the mesh member 20 is transparent, if the mesh member 20 is provided in the light emission path, the light emission on the display screen is adversely affected due to the difference in refractive index from the base material 10. This is not limited to the net-like member shown in the present embodiment, but can generally be said about the relationship between the restraining member according to the present invention and the transparent substrate.
[0023]
As mentioned above, although the Example of the transparent substrate by this invention was described based on FIGS. 1-3, this invention is not limited only to the full color display using an organic electroluminescent light emitting element. For example, a so-called area color display in which only a part of the display screen is full color, or an organic EL display panel compatible with a mono-color display can be handled.
[0024]
Furthermore, the present invention can be applied as long as it has a structure in which a film-like display element is laminated on a transparent substrate. For example, the present invention can also be used for a liquid crystal display panel. ,
[0025]
【The invention's effect】
As described above in detail, according to the present invention, it is possible to easily and accurately position a light emitting cell such as an organic EL during patterning of the light emitting film.
[Brief description of the drawings]
1A is a plan view of a transparent substrate according to an embodiment of the present invention, FIG. 1B is a cross-sectional view taken along line AA ′ in FIG. 1A, and FIG. c) is a cross-sectional view taken along line BB ′ in FIG.
FIG. 2 is a structural diagram in the case where organic EL light emitting cells are configured in a matrix format on the transparent substrate of FIG.
3 is a structural diagram showing a cross-sectional structure of a transparent substrate and an organic EL light emitting cell in the organic EL display panel of FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Base material 20 ... Reticulated member 30 ... Protective film 40 ... Anode electrode 50 ... Organic EL light emitting layer 60 ... Cathode electrode 70 ... Insulating partition

Claims (8)

An image display panel comprising an image display light-emitting layer including a plurality of light-emitting cells, and a transparent substrate carrying the image display light-emitting layer,
Including an insulating partition separating each of the light emitting cells;
The image display panel, wherein the transparent substrate is made of a plastic layer, and a restraining member having a lower thermal expansion coefficient than that of the plastic layer is embedded in at least a part of the plastic layer below the insulating partition .   The said image display light emitting layer is at least 1 organic electroluminescent element which consists of an organic functional layer which consists of an organic compound, and a pair of display electrode which clamps the said organic functional layer. Image display panel. The image display panel according to claim 1 or 2, characterized in that said one of the upper and lower surfaces of the plastic layer is provided a lattice-like recess in at least one said restraining member is embedded in the recess. The image display panel according to claim 1 or 2, characterized in that said one of the upper and lower surfaces of the plastic layer provided stripe-shaped concave portion on at least one said restraining member is embedded in the recess. 5. The image display panel according to claim 3 , wherein at least a bottom surface of the concave portion is blackened, or the restraining member is blackened. 6. The image display panel according to claim 3, wherein a desiccant is mixed in the restraining member. 6. The image display panel according to claim 3, wherein a desiccant is applied to an inner surface of the recess. The image display light emitting layer and the plastic layer, an image display panel according to any one of claims 1 to 7, characterized in that it has a flexibility.

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