JP2005032689A - Plaster type desiccant for organic electroluminescence - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plaster type desiccant for organic EL equipped with a plurality of slits over both front and rear faces and prevented from being blocked on adhesive faces in a shape of bubbles by leaking air outside from the slits even when entrainment of the air occurs at its adhesion to a sealing cap. <P>SOLUTION: The plaster type desiccant 1 for an organic EL is made equipped with a plurality of linear slits 1a in parallel with a feeding direction of a cardboard tape 5 for supplying the desiccant 1 to an adhering process, so that air entrained at the adhesion can be discharged from the slits 1a not to generate protruded parts. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  When manufacturing an organic EL display device, the organic EL element is sealed in a case made of a glass substrate and a sealing cap to improve moisture resistance. In this case, the desiccant is in the form of a plaster (adhesive plaster) for improving workability and can be attached by sticking.

This type of conventional desiccant is composed of a compound that chemically adsorbs moisture and maintains a solid state even after moisture absorption, and the compound is an alkali metal oxide or alkaline earth metal oxide. In addition, when it is disposed in a case, the organic EL element is disposed separately from the organic EL element, and an adhesive is used for the placement in the case.
Japanese Patent Laid-Open No. 09-148066

  The arrangement of the desiccant in the solid state in the case as described above requires, for example, a number of steps such as a pressure-sensitive adhesive application step, an adhesion step, and a drying step, resulting in a problem that production efficiency decreases. It was. As a solution to this problem, the desiccant processed into a granular form, for example, is applied to the other surface of a flexible base material having an adhesive applied on one surface, and the entire plaster (appropriately flexible) Adhesive bandage) It is formed in advance as a desiccant, and this plaster desiccant 90 is attached to a backing tape 91 as shown in FIG. For example, there is one that can be automatically attached to a predetermined position of the sealing cap 12 constituting the case 13 with the glass substrate 11 by an industrial robot.

  However, as described above, the desiccant in the form of a plaster has certainly simplified and speeded up the process of mounting in the case. On the other hand, as shown in FIG. At the time of sticking, air or a dry gas that is the atmosphere of the working environment is entrained to generate a bubble-like protruding portion 90a, and depending on the protruding amount of the protruding portion 90a, it is attached to the glass substrate 11 side. This may cause contact with the organic EL element 14.

  Here, when the desiccant comes into contact with the organic EL element 14, the humidity absorbed by the desiccant affects the organic EL element 14, generates a black spot, and significantly deteriorates the life of the organic EL element 14. Arise. At this time, if the sealing cap 12 has a sufficient depth in order to avoid contact between the desiccant and the organic EL element 14, the organic material is advantageous in that it is originally thin. The characteristics of the EL display device 10 are lost.

  As a specific means for solving the above-described conventional problems, the present invention provides an organic EL element that is attached to the inner surface of the sealing cap with an adhesive when the organic EL element is sealed with a glass substrate and a sealing cap. In the plaster type desiccant, the organic EL plaster type desiccant has a plurality of linear slits parallel to the feed direction of the mount tape for supplying the organic EL plaster type desiccant to the attaching step. By providing the plaster type desiccant for organic EL, which is provided, the problem is solved as the gas does not entrain on the sticking surface at the time of sticking.

  The plaster type desiccant for organic EL of the present invention is provided with a plurality of slits across the front and back surfaces, so that when the gas is entrained at the time of adhering to the sealing cap, the slit causes the gas to the outside. Is prevented from being trapped in the form of bubbles on the sticking surface. Therefore, since the plaster type desiccant for organic EL of the present invention is always in close contact and secured to the sealing cap, the case may be of the minimum necessary thickness, and the organic EL display device Thinning is possible.

  Further, since the above-described configuration does not cause contact between the desiccant and the organic EL element, the organic EL display device can be guaranteed the original lifetime, and the reliability is improved. Furthermore, by making the direction of the slit parallel to the feeding direction of the mount tape, there is also an advantage of reducing the occurrence of defects during the sticking operation.

  Next, the present invention will be described in detail. 1 to 2 is a plaster desiccant for organic EL according to the present invention (hereinafter abbreviated as a plaster desiccant 1). The plaster desiccant 1 is, for example, a resin member. The base material 2 is formed of an appropriately flexible member that does not absorb humidity, and the adhesive material 3 is applied to the sticking surface side, and the desiccant 4 in the form of particles, for example, is attached to the back surface side. It is what. The desiccant 4 may be integrated by being kneaded into the base material 2 or the base material 2 itself has hygroscopicity and has the function of the desiccant 4. It is also good.

  Here, in the present invention, a plurality of slits 1a extending from the sticking surface side to the back surface side of the plaster desiccant 1 are provided, and when the sticking is performed by providing the slits 1a, the sticking surface is provided. Even when air or gas is entrained on the side, air and gas are released from the sticking surface side to the outside through the slit 1a to prevent the formation of bubble-like protrusions.

  As a result of trial production and examination by the inventor for realizing the present invention, it has been found that the position, shape and the like of the slit 1a have a great influence on the required function, work efficiency, cost and the like. Below, the test result of the slit 1a of various shapes which the inventor performed is demonstrated by comparison with a prior art example.

  FIG. 3 shows the situation when the above test is performed, and the conditions are matched with the actual production process. First, the plaster desiccant 1 is adhered to the mount tape 5 at a constant pitch, and the mount tape 5 is wound into a roll shape and supplied to the suction head 20 of the industrial robot. . The suction head 20 sucks and peels off the plaster desiccant 1 from the mount tape 5 and attaches it to a predetermined position of the sealing cap 12 as shown in FIG.

  5 to 10 show the shape of the plaster-type desiccant 1 when the above test is performed. First, the plaster-type desiccant 1 (F) shown in FIG. 10 is a conventional example in which no slit is provided. The results obtained with the plaster type desiccant 1F of this conventional example are used as a reference, and the degree of improvement is determined by comparison with the results.

  FIG. 5 shows the shape of the slit 1a in the plaster desiccant 1 (A). In this embodiment, the slit 1a is the direction of travel of the mount tape 5 to which the plaster desiccant 1A is attached. A plurality of slits 1a are formed in a straight line that is parallel to the. Needless to say, the slit 1a is provided so as to penetrate from the front surface to the back surface of the plaster desiccant 1 (A).

  FIG. 6 shows the shape of the slit 1b in the plaster desiccant 1 (B). In this embodiment, the slit 1b is provided in the form of a number of needle holes on the entire surface of the plaster desiccant 1 (B). ing. FIG. 7 shows the shape of the slit 1c in the plaster desiccant 1 (C). In this embodiment, a plurality of slits 1b are formed in an x shape.

  Furthermore, what is shown in FIG. 8 shows the shape of the slit 1d in the plaster desiccant 1 (D). In this embodiment, the slit 1d has a plurality of linear shapes orthogonal to the traveling direction of the mount tape 5. A slit 1d is formed. In addition, FIG. 9 shows the shape of the slit 1e in the plaster desiccant 1 (E). In this embodiment, the slit 1e has a circular shape.

  Table 1 lists the test results of the plaster type desiccants 1 (A) to (F), and the examination is based on the state at the time of peeling off the mount tape 5 by the suction head 20, and the sealing. Evaluation is performed in terms of the state at the time when the stopper cap 12 is attached to a predetermined position and the manufacturing cost.

  First, in the plaster type desiccant 1 (F) of the conventional example, there is no problem in the process of peeling off from the first mount tape 5, and the pasting to the sealing cap 12 in which 80 out of 80 sheets continue. In this sticking process, gas entrainment was observed in 35 of the 80 sheets, and the overall yield rate was about 56%. However, since the processing for providing the slit is not performed on the plaster type desiccant 1F, the manufacturing cost is the lowest.

  In the plaster type desiccant 1 (A), no defect occurs even in the process of peeling from the backing tape 5 or in the process of sticking to the sealing cap 12, and the overall yield rate is 100. %Met. Further, the process for providing the slit 1a may be performed with a minimum increase in the number of man-hours, and the manufacturing cost is not increased as much.

  In the plaster desiccant 1 (B), no problem occurred in the process of peeling from the backing tape 5, but in the subsequent sticking process to the sealing cap 12, gas was discharged on 5 of the 80 sheets. The overall yield rate was about 94%. Further, the increase in the number of processing when the slit 1b is provided is minimal, but the production cost of the mold is slightly expensive, and the consumption of the mold is considered to be slightly faster. Cost is expected to increase.

  In the plaster type desiccant 1 (C), in the process of peeling from the backing tape 5, 7 peeling defects occurred in 80 sheets, and in the subsequent sticking process to the sealing cap 12, 73 in 80 sheets. Sheets were sent. And the defect did not arise in the sticking process. Therefore, the overall yield rate was about 91%. In addition, the increase in the number of processes when the slit 1c is provided is minimal, but the production cost of the mold is expected to be slightly high, so that the cost increases to about the middle between the slit 1a and the slit 1b. is expected.

  In the plaster desiccant 1 (D), 21 peeling defects occurred in 80 sheets in the process of peeling from the backing tape 5, and no defect occurred in the subsequent sticking process. Therefore, the overall yield rate was about 74%. Moreover, it is thought that the cost increase for providing the slit 1d is equivalent to the slit 1a described above.

  In the plaster desiccant 1 (E), no defect occurs in the process of peeling from the backing tape 5 or the process of attaching to the sealing cap 12, and therefore the overall yield rate is 100%. It was a grade. However, since the slit 1e has a circular shape and an area, after the formation process of the slit 1e, a so-called punched residue is generated, and it takes time and labor to completely remove the punched residue. It was found that the increase was significant.

  As a result of the above examination, the present invention adopts the shape of the slit 1a shown in FIG. 5, and in this way, an organic EL display device employing the plaster desiccant 1 according to the present invention. 4, since the adhesion of the plaster desiccant 1 to the sealing cap 12 can be ensured as shown in FIG. 4, there is a risk of contact between the organic EL element 14 and the plaster desiccant 1. Thus, the case 13 can be set to the minimum necessary thickness, and the organic EL display element 10 can be downsized without fear of affecting the performance such as the lifetime.

It is a perspective view which shows embodiment of the plaster type desiccant for organic EL which concerns on this invention. It is sectional drawing which follows the AA line of FIG. It is explanatory drawing which shows the state of the sticking in the production process of the plaster type desiccant for organic EL which concerns on this invention. It is explanatory drawing which shows the attachment state to the sealing cap of the plaster type desiccant for organic EL. It is explanatory drawing which shows 1st embodiment of the slit formed in the plaster type desiccant for organic EL. It is explanatory drawing which shows 2nd embodiment of the slit similarly formed in a plaster type desiccant. It is explanatory drawing which shows 3rd embodiment of the slit similarly formed in a plaster type desiccant. It is explanatory drawing which shows 4th embodiment of the slit similarly formed in a plaster type desiccant. It is explanatory drawing which shows 5th embodiment of the slit similarly formed in a plaster type desiccant. It is explanatory drawing which shows the plaster type desiccant of a prior art example. It is explanatory drawing which shows the sticking process of a prior art example. It is explanatory drawing which shows the sticking state of a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 (AF) ... Plaster type desiccant for organic EL 1a-1e ... Slit 2 ... Base material 3 ... Adhesive material 4 ... Desiccant 5 ... Mount tape 10 ... Organic EL display element 11 ... Glass substrate 12 ... Sealing cap 13 ... Case 14 ... Organic EL device 20 ... Suction head

Claims (1)

  In the organic EL plaster type desiccant that is attached to the inner surface of the sealing cap with an adhesive when the organic EL element is sealed with the glass substrate and the sealing cap, A plaster desiccant for organic EL, comprising a plurality of linear slits parallel to the feeding direction of the mount tape for supplying the plaster desiccant for EL to the adhering step.

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