JP2015011763A - OLED display panel and manufacturing method thereof - Google Patents

Abstract

An OLED display panel capable of simplifying alignment between a device substrate and a counter glass substrate while preventing a problem that a fill agent pushes out a dam agent from the inside and breaks it. I will provide a. A damming agent 3 applied so as to surround the outer edge of the display area is provided between a device substrate 7 having a display area for displaying an image formed thereon and a counter glass substrate 6. is filled with a filling agent 4 dropped inside. The dam agent 3 is an epoxy resin with relatively high viscosity before curing, and the filling agent 4 is an epoxy resin with relatively low viscosity before curing. A frame-shaped SOC member 5 made of acrylic resin is formed around the application position of the damming agent 3 on the lower surface of the opposing glass substrate 6 , and the tip of the SOC member 5 is in contact with the surface of the device substrate 7 . [Selection drawing] Fig. 1

Description

  The present invention relates to an OLED display panel having a sealing means for an OLED (organic light-emitting diode) element and a method for manufacturing the same.

  In recent years, OLED display panels have been developed for the purpose of reducing the thickness, increasing the brightness, and increasing the speed of display panels. This OLED display panel has a TFT drive circuit layer, a reflective electrode, a hole injection layer, a hole transport layer, an organic light emitting layer, an electron transport layer, and an electron injection corresponding to each pixel on a single glass substrate. An OLED element which is a kind of light emitting diode constituted by laminating a layer and a transparent electrode is provided. Such an OLED display panel has a fast reaction speed because the OLED element does not operate mechanically, and each pixel itself emits light, so that a high-intensity display is possible and a backlight is not required, so that it can be thinned. Therefore, it is expected as a next-generation display panel.

  However, since the organic light emitting layer constituting the OLED element is rapidly deteriorated when exposed to moisture in the atmosphere, it is necessary to be sealed from the outside air. Therefore, various structures for sealing the OLED element have been proposed.

  The structure proposed in the early stage is to seal a glass substrate (device substrate) on which an OLED element is formed with a sealing glass and a sealing material, leaving a space between the device substrate and the sealing glass. Met. However, according to this structure, it is necessary to process the sealing glass in order to secure a place for arranging the desiccant for drying the space, or sealing is performed by applying an external force to the sealing glass. There has been a problem that the inner surface of the glass stop comes into contact with the OLED element and causes black spot defects.

  Therefore, next, a device substrate and a counter glass substrate (when color display is performed using a white light emitting OLED element, a color filter is provided on the inner surface of the counter glass in accordance with the OLED element. A structure has been proposed in which a transparent epoxy resin adhesive is filled in the space between the space and the space between the space and the space. In this structure, how to keep the distance between the device substrate and the counter glass substrate (color filter substrate) constant is a problem. A manufacturing method proposed to solve this problem is a manufacturing method called a DAM / FILL method.

  The DAM / FILL method is a comparison in which gap spacers (polymer beads) are kneaded around a region (display region) where OLED elements are densely formed on the device substrate, as shown in FIG. By interposing a dam agent, which is a hard epoxy resin (having a relatively low viscosity before curing), between the device substrate and the opposing glass substrate (color filter substrate), the distance between the two is fixed. In addition to bonding, the space surrounded by the dam agent is filled with a fill agent that is an epoxy resin having a relatively high viscosity before curing, thereby eliminating air in the space. Thus, since the dam agent having a relatively low viscosity before curing surrounds the fill agent having a relatively high viscosity before curing, the fill agent does not flow out to the surroundings even before the curing, so that the fill agent is all OLED elements. It spreads all over.

  In the manufacturing apparatus adopting such a DAM / FILL method, a dam material is applied on the surface of the device substrate by a dispenser so as to surround the outer edge of the display area along the peripheral edge thereof. Next, the manufacturing apparatus drops a large number of fill agents in the form of dots inside the dam agent. In this way, the filling agent is dropped in the form of dots because the dropped filling agent takes a spherical shape due to its surface tension, so even the filling agent arranged in the form of dots alone is inside the dam agent. This is because a sufficient volume can be obtained. Next, the manufacturing apparatus highly depressurizes the inside of the chamber, and superimposes the device substrate and the counter glass substrate (color filter substrate) while aligning each other. As a result, the filling agent is pushed out, the gap (vacuum) between them is filled, and the space surrounded by both the device substrate and the counter substrate and the dam agent is filled. After that, the manufacturing device performs the curing treatment of the dam agent and the fill agent, returns the atmospheric pressure in the chamber to atmospheric pressure, takes out the one on which the device substrate and the counter glass substrate (color filter substrate) are bonded, and makes a product unit. Cut into

JP 2010-287421 A

When the above-mentioned DAM / FILL method is adopted, the height of the dam agent can be controlled relatively strictly by mixing the gap spacer, so that the distance between the device substrate and the counter glass substrate (color filter substrate) determined by this can be adjusted. If the same amount of fill agent as the volume of the inner space of the dependent dam agent is dropped, the fill agent will not leak to the outside of the dam agent.

  However, in reality, the volume of the fill agent that can be accommodated in the inner space of the dam agent is larger than the volume of the dropped fill agent due to the bending of an external force applied to the center of the counter glass substrate (color filter substrate). It may become smaller. In this case, since all of the dropped fill agent cannot be kept in the inner space of the dam agent, the excess fill agent pushes the dam agent before curing from the inside, causing the dam agent to break, and to the outside. Leaks out. Such a problem can also occur due to other causes such as the height of the dam agent and the variation in the application position.

  In order to prevent such dam agent breakage, it is sufficient to predict the amount of deflection of the counter glass substrate (color filter substrate) in advance and reduce the total amount of fill agent by the amount of decrease in the inner space of the dam agent. Conceivable. However, in reality, as the counter glass substrate (color filter substrate) does not bend as expected, there is a problem that bubbles (vacuum voids) are generated in the fill agent filled in the inner space of the dam agent. Arise.

  In FIG. 7 of Patent Document 1, a spacer layer is provided on the counter glass substrate (color filter substrate) side to secure a distance from a bump (partition wall) separating OLED elements existing on the outer edge of the display area on the device substrate. Since the spacer layer is pierced into the dam agent applied on the bump, the effect of pressing the dam agent and the fill agent into the spacer layer is expected. However, in such a configuration, when the OLED element constituting the display region is made high definition, it becomes difficult to pierce the dam agent applied to the upper surface of the bump (partition wall), and in some cases, the spacer layer There is a problem that the dam agent is cut by itself and the inside and outside communicate with each other.

In view of the above, the problem of the present invention is that the alignment between the device substrate and the counter glass substrate can be prevented despite the fact that the fill agent can completely prevent the problem that the dam agent is pushed out from the inside and destroyed. An OLED display panel that can be simplified and a method for manufacturing the same are provided.

  An OLED display panel according to the present invention is an OLED display panel formed by sealing a display region having an OLED element, the device substrate on which the display region is formed, a transparent counter glass substrate, the device substrate, and the device substrate. Between the counter glass substrate, a dam agent which is an adhesive disposed so as to surround an outer edge of the display region, and a space surrounded by the device substrate, the counter glass substrate and the dam agent were filled. A fill agent, which is a transparent adhesive having a higher viscosity before curing than the dam agent, and a surface of the device substrate bonded to the dam agent, and the dam agent in the device substrate is surrounded by the dam agent. And a frame member in contact with the surface bonded to the surface.

  A method for manufacturing an OLED display panel according to the present invention is a method for manufacturing an OLED display panel in which a display region having an OLED element is sealed. The display region is formed on the surface of a device substrate, and is transparently opposed. Form a frame member surrounding the application position of the dam agent set in the shape and size of the frame surrounding the outer edge of the display area on the surface of the glass substrate, and adhere to the application position on the surface of the counter glass substrate An agent is applied as the dam agent, and in a region surrounded by the dam agent on the surface of the counter glass substrate, a fill agent that is a transparent adhesive having a higher viscosity before curing than the dam agent is dropped, and With the dam agent positioned so as to surround the display area, the tip of the frame member and the dam agent are brought into contact with the surface of the device substrate, and the dam agent and the fill agent The curing, characterized.

According to the OLED display panel and the manufacturing method thereof according to the present invention configured as described above, it is possible to completely prevent the problem that the fill agent pushes the dam agent from the inside and breaks it. The effect that the alignment of a device substrate and a counter glass substrate can be simplified is acquired.

1 is a schematic longitudinal sectional view of an OLED display panel according to a first embodiment of the present invention. A longitudinal sectional view showing a part of FIG. 1 in detail The longitudinal cross-sectional view which expanded and showed the OLED element in FIG. The top view which shows the manufacturing process of an OLED display panel The top view which shows the manufacturing process of an OLED display panel The top view of the OLED display panel by 2nd Embodiment of this invention. Explanatory drawing of 2nd Embodiment

Hereinafter, the best mode for carrying out an OLED display panel according to the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 shows a schematic longitudinal section during the manufacturing process of the OLED display panel according to the first embodiment of the present invention (immediately before separation for each product). As shown in FIG. 1, an OLED display panel 1 includes an OLED substrate 10 formed by forming OLED elements 12 for a large number of pixels (only six are shown in FIG. 1) on the upper surface of a glass substrate 11, and each OLED element. 12 surrounds the display area 12 (area where the OLED elements 13 are densely formed) between the lower surface of the opposing glass substrate 2 and the upper surface of the OLED substrate 11. A dam agent (transparent epoxy adhesive with a relatively low viscosity before curing) 3 applied to a rectangular frame mold and a fill agent (a transparent with a relatively high viscosity before curing) filled in the inner space of the dam agent 3 (Epoxy adhesive) 4 and a rectangular frame-shaped SOC member 5 formed at a position surrounding the application position of the dam agent 4 on the lower surface of the counter glass substrate 2.

  FIG. 2 is an enlarged longitudinal sectional view of the OLED display panel 1 including the OLED elements 13 existing on the outer edge of the display area 12, and FIG. 3 is an enlarged longitudinal sectional view further showing a detailed structure of the OLED elements 13. .

  The OLED element 13 is roughly composed of a drive circuit layer 14 and an OLED layer 15. The drive circuit layer 14 is formed so as to cover the first insulating layer 16 formed on the upper surface of the glass substrate 11, the gate wiring 17 formed by patterning on the insulating layer 16, and the gate wiring 17. A second insulating layer 18; a semiconductor layer 20 formed above the end (gate electrode) of the gate wiring 17 with the second insulating layer interposed therebetween; a planarizing layer 19 that embeds the semiconductor layer 20; A pair of wirings (source wiring 21 and drain wiring) which are patterned on the layer 19 and whose end portions extend into contact holes formed on the upper surface of the planarizing layer 19 and face each other with the semiconductor layer 20 interposed therebetween. 22), and an anode 23 formed at the other end of the drain wiring 22 so as to have a shape corresponding to each pixel is a main component.

  The OLED layer 15 is flat on the anode 23 in order to separate the organic EL layer 25 formed to have a similar shape to the anode 23 from the organic EL layer 25 of other adjacent pixels. The bank 24 formed on the activating layer 19, the organic EL layer 25, the transparent cathode 26 formed on the upper surface of the bank 24, and the OLED protective film 27 formed so as to cover the transparent cathode 26 are mainly used. As a component.

  In more detail, the organic EL layer 25 includes a hole transport layer 25a, a hole transport layer 25b, a light emitting layer 25c, an electron transport layer 25d, and an electron injection layer 25e that are stacked in this order from the anode 23 side. Has been. Then, according to a signal applied to the gate wiring 17, the field effect transistor (gate electrode, semiconductor 17, source wiring 21, drain wiring 22) supplies holes to the anode 23 and electrons supplied to the transparent cathode 27. However, they reach the light emitting layer 25c through the hole transport layer 25a, the hole transport layer 25b, the electron injection layer 25e, and the electron transport layer 25d, respectively, and recombine in the light emitting layer 25c to emit light.

  The SOC member 5 is a frame member formed from a photocurable acrylic resin. Since this SOC member 5 is sufficiently harder than the dam agent 3 before curing, it functions as a gap spacer that keeps the distance between the surface of the OLED substrate 10 and the lower surface of the counter glass substrate 2 constant. Accordingly, the thickness of the SOC member 5 is designed to be the same value as the design value of the distance between the surface of the OLED substrate 10 and the lower surface of the counter glass substrate 2.

  The dam agent 3 adheres and fixes the upper surface of the OLED substrate 10 and the lower surface of the counter glass substrate 2 between the OLED element 12 and the SOC member 5 existing at the outer edge of the display area on the OLED substrate 10, It serves to seal the gap. Although the SOC member 5 is provided, the dam agent 3 is still necessary because the SOC member 5 formed on the lower surface of the counter glass substrate 2 is simply in contact with the OLED substrate 10. This is because the function of preventing the leakage of the fill agent 4 cannot be achieved. However, since the SOC member 5 functions as a spacer, the kneading of the gap spacer (polymer beads) into the dam agent 3 is omitted.

  The fill agent 4 adheres and fixes the upper surface of the OLED substrate 10 and the lower surface of the counter glass substrate 2 together with the dam agent 3, and the space surrounded by the OLED substrate 10, the counter glass substrate 2, and the dam agent 3. It fills and functions to prevent air from entering the space.

  The manufacturing process of the OLED display panel 1 configured as described above will be described. First, by forming a display area (OLED display element 12) for a plurality of products on a single large substrate glass 11, OLED substrates 10 for a plurality of products are created.

  On the other hand, as shown in FIG. 4, SOC members 5 for a plurality of products are formed on the lower surface of one large counter glass substrate 2. The SOC member 5 may be formed by a method in which a photocurable acrylic resin is applied in a rectangular shape by a dispenser and then photocured, or after the photocurable acrylic resin is uniformly applied to the lower surface of the counter glass substrate 2. Alternatively, photolithography may be used in which light is irradiated through a mask having a rectangular pattern.

  Next, as shown in FIG. 5, an uncured dam agent 3 is applied to the inside of each SOC member 5 formed on the lower surface of the counter glass substrate 2 in a rectangular shape by a dispenser. Inside, the fill agent 4 is dropped at predetermined pitches in two orthogonal directions. The amount of the fill agent 4 is determined based on the distance between the upper surface of the OLED substrate 10 regulated by the SOC member 5 and the lower surface of the counter glass substrate 2 on the assumption that the counter glass substrate 2 is not bent. It matches the volume of the internal space.

  Then, the OLED substrate 10 and the counter glass substrate 2 are accommodated in a chamber (not shown), the inside of the chamber is decompressed, and then the OLED substrate so that each dam agent 3 surrounds each display region on the upper surface of the OLED substrate 10. In a state where the counter glass substrate 2 is aligned with respect to 10, the tips of the SOC members 5 are brought into contact with the periphery of the display area on the upper surface of the OLED substrate 10 to bond them together. At this time, the drop of the fill agent 4 is spread by the lower surface of the opposing glass substrate 2, but in an ideal state where the opposing glass substrate 2 is not bent and no air molecules are present in the internal space of the dam agent 3. If there is, the whole of the filling agent 4 is completely accommodated in the space surrounded by the OLED substrate 10, the counter glass substrate 2 and the dam agent 3. Although it is spread over the entire space surrounded by the substrate 10 and the counter glass substrate 2 and the dam agent 3 (FIGS. 1 and 2), the fill agent 4 does not push the dam agent 3 outward.

  Moreover, the total volume of the fill agent 4 and the dam agent 3 is only slightly smaller than the volume of the space surrounded by the OLED substrate 10, the counter glass substrate 2 and the SOC member 53. Therefore, due to the counter glass substrate 2 being bent, the volume of the space surrounded by the OLED substrate 10 and the counter glass substrate 2 and the dam agent 3 becomes smaller than the volume of the fill agent 4, and as a result, the fill agent 4. Even if the dam agent 5 is pushed outward, the SOC member 5 regulates the movement of the dam agent 5, so that the force that the fill agent 4 pushes the dam agent 5 outward is equal over the entire circumference of the dam agent 5. (The dam agent 5 is evenly pushed outward on the inside of the SOC member 5). Therefore, it is avoided that the force with which the filling agent 4 pushes the dam agent 5 outward is concentrated in one place, so that the dam agent 5 is prevented from being broken.

  Therefore, a manufacturing apparatus (not shown) cures the dam agent 3 and the fill agent 4 by performing a curing process (heat irradiation, light irradiation, etc.) according to the characteristics of the dam agent 3 and the fill agent 4.

Finally, the chamber is returned to atmospheric pressure, the bonded product of the OLED substrate 10 and the counter glass substrate 2 is taken out, and the bonded product is cut into each product, thereby completing the OLED display panel 1 for a plurality of products. To do. At this time, as described above, since the dam agent 3 is not broken, the fill agent 4 is not scattered outside the SOC member 5. Therefore, the cutting process can be shortened in time.
(Embodiment 2)

  According to the first embodiment described above, as long as air molecules do not remain in the chamber, even if the counter glass substrate 2 is bent, the extrusion of the dam agent 3 due to it is held down by the SOC member 5, and the dam agent 3 is distributed evenly over the entire circumference of the dam agent (the dam agent 5 is evenly pushed outward inside the SOC member 5), so that the dam agent 3 gets over the SOC member 5 and the SOC member 5 There is no problem that the space between the OLED substrate 10 and the OLED substrate 10 is spread or broken as a result.

  However, when the degree of vacuum in the chamber is insufficient, air molecules remain between the dam agent 3 and the SOC member 5. In this case, since the air molecules should have existed evenly in the chamber, it is the reason that the air molecules remain inside the dam agent 3. Therefore, in this case, since the total amount of the fill agent 4 that can be accommodated in the inner space of the dam agent 3 is smaller than the ideal state described above, when the counter glass substrate 2 is bent, the dam agent is larger than the ideal state described above. 3 is pushed outward. In addition, in this case, since air molecules remain between the dam agent 3 and the SOC member 5, the dam agent 3 cannot move uniformly toward the SOC member 5 over the entire circumference. As a result, the dam agent 3 that has lost its place travels over the SOC member 5, spreads between the SOC member 5 and the OLED substrate 10, and as a result, the possibility of breaking down remains.

  Therefore, in this embodiment, even if the degree of vacuum in the chamber is insufficient, the dam agent 3 gets over the SOC member 5 and spreads between the SOC member 5 and the OLED substrate 10, or as a result, it breaks down. A device has been devised to avoid the problem of misuse. That is, in the present embodiment, as shown in FIG. 6, the four corners of the SOC member 5 are cut out.

  That is, the air molecules remaining between the dam agent 3 and the SOC member 5 gather together to form bubbles B and move to each corner of the SOC member 5 as shown in FIG. Present. Therefore, if a notch is provided at each corner, air molecules remaining between the dam agent 3 and the SOC member 5 can be excluded. Thereby, the dam agent 3 comes to be uniformly pushed outward until it contacts the SOC member 5 over the entire circumference.

  In addition, by cutting out each corner of the SOC member 5, the dam agent 3 can enter the cutout portion. As a result, a part of the dam agent 3 extruded larger than the ideal state described above due to the air molecules remaining in the internal space of the dam agent 3 is allowed to escape into the notch, and from the fill agent 4 added to the dam agent. Pressure can be relieved. However, since the width of the notch portion is narrow and the fill agent 4 together with the dam agent 3 does not bulge out from the notch portion, the dam agent 3 does not break.

DESCRIPTION OF SYMBOLS 1 OLED display panel 2 Opposite glass substrate 3 Dam agent 4 Fill agent 5 SOC member 11 Glass substrate 12 OLED element

Claims (8)

An OLED display panel formed by sealing a display region having an OLED element,
A device substrate on which the display area is formed;
A transparent counter glass substrate;
Between the device substrate and the counter glass substrate, a dam agent that is an adhesive disposed so as to surround an outer edge of the display area;
A fill agent which is a transparent adhesive having a higher viscosity before curing than the dam agent filled in the space surrounded by the device substrate and the counter glass substrate and the dam agent;
A frame member formed on a surface of the device substrate bonded to the dam agent, and surrounding the dam agent and contacting a surface of the device substrate bonded to the dam agent. OLED display panel. The display area is rectangular;
2. The OLED display panel according to claim 1, wherein a planar shape of the frame member is a rectangle. The OLED display panel according to claim 2, wherein each corner of the frame member is cut out. The OLED display panel according to claim 1, wherein the frame member is made of an acrylic resin material. A method for manufacturing an OLED display panel in which a display region having an OLED element is sealed,
Forming the display area on the surface of the device substrate;
Forming a frame member surrounding the application position of the dam agent set in a frame shape and a size surrounding the outer edge of the display region on the surface of the transparent counter glass substrate;
Applying an adhesive as the dam agent to the application position on the surface of the counter glass substrate,
In a region surrounded by the dam agent on the surface of the counter glass substrate, a fill agent that is a transparent adhesive having a higher viscosity before curing than the dam agent is dropped,
With the dam agent positioned so as to surround the display area, the tip of the frame member and the dam agent are brought into contact with the surface of the device substrate,
A method for manufacturing an OLED display panel, wherein the dam agent and the fill agent are cured. 6. The method of manufacturing an OLED display panel according to claim 5, wherein the total amount of the filling agent is the same as the volume of the space surrounded by the device substrate, the counter glass substrate, and the dam agent. The display area is rectangular;
6. The method of manufacturing an OLED display panel according to claim 5, wherein the planar shape of the frame member is rectangular. 8. The method of manufacturing an OLED display panel according to claim 7, wherein each corner of the frame member is cut out.

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