KR100889834B1 - Mesuring device for permeation rate of water and oxygen of protective layer in organic electronic device and measuring method using the device - Google Patents

Abstract

The present invention relates to an apparatus for measuring moisture permeability and oxygen permeability of an organic electronic device protective layer and a measuring method using the apparatus, and more specifically, comprising: a glass substrate; A pair of electrode layers oppositely stacked on the glass substrate; A calcium layer laminated on the glass substrate; A moisture-permeable and oxygen-permeable substrate stacked on the calcium layer; A measurement target organic electronic device protective layer stacked on the moisture permeable and oxygen permeable substrate; And a sealing material applied along an outer surface of the protective layer of the organic electronic device to be measured, wherein one end of the electrode layer is embedded in the calcium layer, and the other end is electrically connected to an external resistance measuring device. The present invention relates to an apparatus for measuring moisture permeability and oxygen permeability of an electronic device protective layer and a measuring method using the apparatus.

According to the present invention, by using the principle that the electrical characteristics of the measuring device is changed as the protective layer is breathable or oxygen permeable, it is not influenced by the reflectivity or transmittance of the protective layer, and is applicable to various organic electronic device protective layer processes. Unlike the prior art, there is no need to perform averaging of defects on the calcium layer inside the device, and a highly reliable moisture permeability and oxygen permeability measuring device for an organic electronic device protective layer and a measuring method using the device Can be provided.

Organic electronic device, protective layer, moisture permeability, oxygen permeability

Description

Measuring device for permeation rate and oxygen permeability of the organic electronic device protective layer and measuring method using the device {Mesuring device for permeation rate of water and oxygen of protective layer in organic electronic device and measuring method using the device}

1 shows a schematic plan view of a measuring device according to the invention.

FIG. 2 is a schematic cross-sectional view of the device of FIG. 1 viewed along line I-I of FIG.

FIG. 3 is a graph illustrating moisture permeability characteristics when a glass substrate is applied as a material to be measured to the measuring apparatus shown in FIGS. 1 and 2, and a plastic substrate (b) having no protective layer formed thereon. to be.

FIG. 4 illustrates a case in which a conventional protective layer material is further formed on the plastic substrate in addition to the glass substrate (a) and the plastic substrate (b) shown in FIG. 3 and formed on both sides of the plastic substrate. It is a graph showing the moisture vapor transmission characteristics for case (d).

<Brief description of the major symbols in the drawings>

110, 210: calcium layer 120, 220: sealing material

130, 230: moisture-permeable and oxygen-permeable substrates 140, 240: protective layer

150, 250: electrode 160, 260: glass substrate

170, 270: resistance measuring device

The present invention relates to an apparatus for measuring moisture permeability and oxygen permeability of an organic electronic device protective layer and a measuring method using the apparatus. More specifically, the principle that the electrical characteristics of the measuring apparatus changes as the protective layer is permeable or oxygenated. By increasing the efficiency of the protective layer process of various organic electronic devices without being affected by the reflectivity or transmittance of the protective layer, it is necessary to perform averaging of defects on the calcium layer inside the device differently from the prior art. The present invention relates to an apparatus for measuring moisture permeability and oxygen permeability of an organic electronic device protective layer having high reliability and a measuring method using the apparatus.

Organic light emitting diode (OLED) is a self-luminous display that electrically excites fluorescent organic compounds to emit light, which can be driven at low voltage, is easy to thin, and is pointed out as a problem in liquid crystal display devices such as wide viewing angle and fast response speed. It is attracting attention as the next generation display that can solve the shortcomings.

However, the internal light emitting layer and the other functional layers constituting the organic electronic device including the organic light emitting device are composed of organic materials, and due to the nature of the organic materials, they react sensitively to the external environment, especially moisture and outdoor air, and thus have a long lifetime. In order to secure long-life characteristics without any change in color purity and characteristics even if used, an encapsulation structure or a sealing structure is required to prevent the penetration of moisture and external air.

As a technology for preventing the penetration of moisture and outside air of the organic electronic device, conventionally, a metal can or glass is processed in the form of a cap to have a groove, and a desiccant for absorbing moisture is mounted in the groove in powder form, or a film It was prepared in the form of a double-sided tape was used to adhere (US Pat. No. 5,771,562 and Japanese Patent Laid-Open No. 03-261091), and also by alternately depositing organic and inorganic on the organic light emitting unit alternately a protective layer. Forming methods are also used (US Pat. No. 6,266,695 and US Pat. No. 6,570,325).

Therefore, the development of an apparatus and method capable of effectively, accurately and conveniently measuring the moisture permeability and oxygen permeability of various organic and inorganic materials that can be employed in organic electronic devices is essential in the development of the encapsulation structure or the sealing structure of the organic electronic device. In the protective layer currently employed in organic light emitting devices, the moisture vapor transmission rate of water vapor and oxygen is 10 ^-6 g / m ² / day and 10 ^-3 cm ³ / m of water vapor at an appropriate temperature and pressure. ^It should be measured very precisely up to ² / day.

In the case of Mocon Inc. (Minneapolis, MN, USA) equipment of the United States, which is widely used to measure the moisture permeability of organic electronic devices, the moisture permeability is measured in a limited range up to 5 × 10 ^-3 g / m ² / day. can do. However, such a measurement range has a problem that it is difficult to obtain a quantitatively accurate value in manufacturing a protective layer of an organic electronic device. In addition, another method is to measure moisture permeability by optically analyzing the surface of the oxidized calcium while observing the growth of point defects in the calcium layer over time and measuring the degree of oxidation. There is also a method of measuring the moisture permeability by measuring the degree of oxidation by measuring the reflectance or transmittance of. However, these methods also adopt a method of taking average values by measuring the transmittance of each point in the total area of the calcium layer, and there is a problem that a very complicated task is involved because the protective layers have different initial transmittance and wavelength ranges.

Accordingly, the first technical problem to be achieved by the present invention is not affected by the reflectivity or transmittance of the protective layer, and has excellent applicability to various organic electronic device protective layer processes, and performs averaging of defects on the calcium layer inside the device. There is no need to perform, and to provide a device for measuring the moisture permeability and oxygen permeability of a highly reliable organic electronic device protective layer.

In addition, a second technical problem to be achieved by the present invention is to provide a method for measuring the moisture permeability and oxygen permeability of the protective layer of the organic electronic device using the device.

The present invention to achieve the first technical problem,

Glass substrates;

A pair of electrode layers oppositely stacked on the glass substrate;

A calcium layer laminated on the glass substrate;

A moisture-permeable and oxygen-permeable substrate stacked on the calcium layer;

A measurement target organic electronic device protective layer stacked on the moisture permeable and oxygen permeable substrate; And

It includes a sealing material applied along the outer periphery of the measurement target organic electronic device layer,

One end of the electrode layer is embedded in the calcium layer, the other end provides an apparatus for measuring the moisture permeability and oxygen permeability of the organic electronic device protective layer, characterized in that it is electrically connected to the external resistance measuring device.

According to a preferred embodiment of the present invention, the electrode layer may be an Ag material layer or Au material layer.

According to another preferred embodiment of the present invention, the lamination thickness of the calcium layer may be 50nm to 500nm.

According to another preferred embodiment of the present invention, the moisture-permeable and oxygen-permeable substrate may be a plastic selected from the group consisting of polyethylene, polypropylene, polystyrene, polyethersulfone and polycarbonate or a synthetic resin substrate using the same.

According to another preferred embodiment of the present invention, the sealing material may be a UV curable epoxy resin.

In addition, the present invention to achieve the second technical problem,

Stacking a protective object organic electronic device protective layer on the moisture-permeable and oxygen-permeable substrate of the device;

Measuring a change in resistance value over time while applying a voltage to the one end of the electrode layer of the device through the external resistance measuring device;

Measuring the change in height over time of the calcium layer by substituting the measured resistance into Equation 1; And

The moisture permeability and oxygen permeability of the protective layer of organic electronic device comprising the step of measuring the change in the height of the calcium layer in the following equation (2) and (3) to measure the moisture permeability and oxygen permeability of the protective target organic electronic device layer. Provide a measurement method:

In Equations 1 to 3,

Δh is the change in height of the calcium layer (the height of the reacted calcium layer), R is the resistance value of the calcium layer, R _i is the initial resistance value of the calcium layer, and h _i is the initial height of the calcium layer (the amount of deposited calcium Height), M (H ₂ O) is the molecular weight of water, M (Ca) is the molecular weight of calcium, M (O ₂ ) is the molecular weight of oxygen, δ is the density of calcium, and Δhr is the elapsed time. .

According to a preferred embodiment of the present invention, the voltage application range through the external resistance measuring device may be 0.1mV to 20mV.

According to another preferred embodiment of the present invention, the moisture permeability and permeation of the protective layer of the organic electronic device on the basis of the change in the resistance value with respect to the moisture permeable and permeable substrate itself and the change in resistance over time with respect to the glass substrate as a reference value The method may further include measuring a small rate.

According to another preferred embodiment of the present invention, the organic electronic device may be selected from the group consisting of an organic light emitting device, an organic thin film transistor and an organic capacitor.

According to the present invention, by using the principle that the electrical characteristics of the measuring device is changed as the protective layer is breathable or oxygen permeable, it is not influenced by the reflectivity or transmittance of the protective layer, and is applicable to various organic electronic device protective layer processes. Unlike the prior art, there is no need to perform averaging of defects on the calcium layer inside the device, and a highly reliable moisture permeability and oxygen permeability measuring device for an organic electronic device protective layer and a measuring method using the device Can be provided.

Hereinafter, the present invention will be described in more detail.

The present invention is conceived in view of the fact that the electrical resistance value of calcium, which is very vulnerable to moisture and oxygen in the atmosphere, changes with time. In particular, calcium is a conductive metal, but when reacted with moisture and oxygen in the atmosphere, it is converted into calcium hydroxide, which is electrically insulated. When measuring the change in resistance of calcium over time, the amount of calcium hydroxide produced and the amount of residual calcium The amount of water and oxygen permeated can be obtained quantitatively. At this time, the chemical reaction of calcium with water and oxygen is as shown in Schemes 1 to 3 below:

One calcium atom in Schemes 1 and 2 reacts with two H ₂ O molecules to produce Ca (OH) ₂ , and one calcium atom in Scheme 3 reacts with 0.5 O ₂ molecules to generate CaO. At this time, oxygen and water vapor are independent and have different permeation mechanisms, and in order to measure the moisture permeability rate and the oxygen permeability rate, an environment in which water and oxygen are mostly in a closed space is required. Therefore, after setting an inert gas environment such as nitrogen in the measurement chamber, it is preferable to measure the moisture permeability and oxygen permeability using a method of injecting water vapor or oxygen.

In order to measure the moisture permeability and oxygen permeability using the calcium, the present invention provides a glass substrate; A pair of electrode layers oppositely stacked on the glass substrate; A calcium layer laminated on the glass substrate; A moisture-permeable and oxygen-permeable substrate stacked on the calcium layer; A measurement target organic electronic device protective layer stacked on the moisture permeable and oxygen permeable substrate; And a sealing material applied along an outer surface of the protective layer of the organic electronic device to be measured, wherein one end of the electrode layer is embedded in the calcium layer, and the other end is electrically connected to an external resistance measuring device. Provided is an apparatus for measuring moisture permeability and oxygen permeability of an electronic device protective layer.

1 and 2 show a schematic plan view and a cross-sectional view of the measuring device according to the present invention. Referring to FIGS. 1 and 2, first, the moisture permeability is 10 ⁻⁶ g / m ² / day or less, which is extremely moisture permeable. On the weak glass substrates 160 and 260, a pair of electrode layers 150 and 250 are formed by a thermal evaporation process or the like.

The electrode layers 150 and 250 are very resistant to electrochemical corrosion and are not easily oxidized compared to other metals, and are preferably metal layers having low resistance and low oxidation, but are not limited thereto. Or Ag material layer. This is because the present invention adopts a method of calculating the moisture permeability through the electrical properties, the electrochemical corrosion between the electrode layers 150 and 250 and the probe of the external resistance measuring device 170 and 270 or the oxidation of the electrode itself. This is because accurate measurement is impossible.

1 and 2, calcium layers 110 and 210 are formed on the electrode layers 150 and 250, where calcium is easily oxidized in the atmosphere as described above. 110 and 210, the vacuum state in the chamber for thermal deposition should be a high vacuum state of <10 ^-6 torr or less.

The thickness of the calcium layers 110 and 210 is preferably 50 nm to 500 nm. Laminating the calcium layer below 50 nm is difficult in the process, and when it exceeds 500 nm, a long time is required to detect a change in electrical characteristics. This is because it is not preferable because there is a problem that the sensitivity is lowered during measurement.

Subsequently, in the apparatus according to the present invention, the moisture-permeable and oxygen-permeable substrates 130 and 230 are laminated on the calcium layers 110 and 210, which are subjected to various protective layer processes. It should be made of a material that can be applied and that is very easy to penetrate moisture and oxygen compared to the protective layer. Thus, but not limited thereto, a plastic selected from the group consisting of polyethylene, polypropylene, polystyrene, polyethersulfone, and polycarbonate or a synthetic resin substrate using the same may be used. The plastic substrate not only serves as a support for supporting the protective layers 140 and 240, but also serves to allow the moisture and oxygen passing through the protective layers 140 and 240 to react with calcium in a short time. The moisture permeability and oxygen permeability of the protective layers 140 and 240 can be evaluated.

Next, after applying the sealing material 120 and 220 to the edge of the substrate to which the protective layers 140 and 240, which are the objects of measurement of moisture permeability and oxygen permeability, are applied through an injector, FIG. 1 through hardening of the sealing material. And in the form as shown in FIG. 2. UV-curable epoxy resin may be used as the sealant 120 and 220.

The sealing member 120 and 220 should be able to block the penetration of moisture and outside air so that the moisture infiltration at the edge portion does not determine the moisture permeability, for this purpose, the sealing material is applied to the edge multiplely, or a getter is provided. By doing so, it is possible to more completely block the penetration of moisture and outside air at the edges.

The entire process of the manufacturing process for the device according to the invention described above takes place under a glove-box system, ie an inert gas environment such as nitrogen, and the thermal evaporation chamber is also located in this glove-box. This is to prevent the calcium layers 110 and 210 from oxidizing during the manufacture of the device.

After curing of the sealant 120 and 220, the device according to the invention comprising the measurement sample is transferred to a measurement chamber set in a moisture or oxygen environment, wherein the electrode layer is embedded by the calcium layers 110 and 210. The other electrode layer end which is connected to the end is electrically connected to the external resistance measuring apparatus 170 and 270. The external resistance measuring devices 170 and 270 are devices capable of measuring voltage or current over time. The external resistance measuring devices 170 and 270 may be multimeter systems such as Keithley 237, and the measurement is performed through an I-V curve over time.

The present invention also to achieve the above other technical problem,

Depositing a measurement target organic electronic device protective layer on the moisture-permeable and oxygen-permeable substrate of the device; Measuring a change in resistance value over time while applying a voltage to one end of the electrode layer of the device through the external resistance measuring device; Measuring the change in height over time of the calcium layer by substituting the measured resistance into Equation 1; And measuring the moisture permeability and oxygen permeability of the measurement target organic electronic device protective layer by substituting the height change amount of the calcium layer into Equations 2 and 3 below. Provides a small rate measurement method:

<Equation 1>

<Equation 2>

<Equation 3>

In Equations 1 to 3,

Δh is the change in height of the calcium layer (the height of the reacted calcium layer), R is the resistance value of the calcium layer, R _i is the initial resistance value of the calcium layer, and h _i is the initial height of the calcium layer (the amount of deposited calcium Height), M (H ₂ O) is the molecular weight of water, M (Ca) is the molecular weight of calcium, M (O ₂ ) is the molecular weight of oxygen, δ is the density of calcium, and Δhr is the elapsed time. .

In this case, in order to minimize the electrochemical corrosion between the electrode layers 150 and 250 and the probe of the external resistance measuring device, the applied voltage preferably has a voltage value of about 0.1 mV to 20 mV, and also an external resistance measuring device. The 4-point probe system can be used to prevent short circuits or minute shaking of current values when measuring micro currents.

In the apparatus and method for measuring moisture permeability and oxygen permeability according to the present invention, the moisture permeation or oxygen permeation is made only through the moisture permeable and oxygen permeable substrates 130 and 230 and the protective layers 140 and 240 stacked on top of the apparatus. In other words, moisture permeation and oxygen permeation through the electrode layers 150 and 250, the sealing materials 120 and 220 and the lower glass substrates 160 and 260 are hardly achieved and are in the range of 10 ^-6 g / m ² / day or less. If it is made to satisfy the moisture permeability reproduction range for the organic light emitting device protective film.

In the present invention, the principle that the resistance value of the device changes is as follows. That is, the oxidation starts from the upper surface of the calcium layer (110 and 210) due to the penetration of moisture, the CaO layer is generated on the upper surface of the calcium layer (110 and 210) according to the reaction formula 1, and further moisture permeation In the CaO and the water reacts to form a Ca (OH) ₂ layer in accordance with Scheme 2, the resistance is further increased as this process proceeds.

Typically, the water vapor transmission rate is expressed in g / m ² / day, and the initial calcium height can be normalized to the initial current value (V / R) immediately after the start of the measurement. For example, when all of calcium becomes calcium hydroxide and becomes an insulator, the resistance value becomes infinity and the current value also appears as zero. In this respect, the measurement of the resistance value is an indication of its thickness and can be usefully used to determine the moisture permeability. As a result, the height of the reduced calcium layer 110 and 210 with respect to the elapsed time may be derived from the following Equation 1 through the change in the electrical properties according to the oxidation of the calcium layer 110 and 210:

<Equation 1>

.

.

Subsequently, the height change of the calcium layer obtained from Equation 1 may be used to calculate the moisture permeability and oxygen permeability by substituting Equations 2 and 3 below:

<Equation 2>

<Equation 3>

In Equations 1 to 3,

Δh is the change in height of the calcium layer (the height of the reacted calcium layer), R is the resistance of the calcium layer, R _i is the initial resistance of the calcium layer, and h _i is the initial height of the calcium layer (the amount of deposited calcium Height), M (H ₂ O) is the molecular weight of water, M (Ca) is the molecular weight of calcium, M (O ₂ ) is the molecular weight of oxygen, δ is the density of calcium, and Δhr is the elapsed time. .

In this case, the amount of change in resistance over time for the moisture permeable and oxygen permeable substrate itself, and the amount of change in resistance over time with respect to the glass substrate may be used as reference values for measuring the moisture permeability and oxygen permeability of the protective layer to be measured. .

In the practical application of the device or method according to the invention, the decrease in calcium height is not horizontal, for example, even if one calcium molecule reacts, the changed resistance value is the extent to which the decrease is horizontally dispersed and reduced. Same as This is possible because it is the premise that the calcium layer is a set of resistors, and in this respect, it can be seen that the present invention enables accurate measurement of moisture permeability and oxygen permeability in a short time compared to conventional methods.

The device or method according to the present invention can be used to measure the moisture permeability and oxygen permeability of various organic electronic devices, and can be applied to organic electronic devices selected from the group consisting of organic light emitting devices, organic thin film transistors and organic capacitors. In addition to the application to the display, it can be variously applied to the process requiring the measurement of the permeability of moisture and oxygen, such as substrate and encapsulation process, microsystem packaging process.

Example

Preparation of the device according to the invention

A glass substrate having a thickness of 1.1 mm was used as a substrate. A 250 nm thick Ag electrode was formed on the substrate, and a calcium layer was deposited to a thickness of 500 nm to bury the end of the electrode. As the moisture-permeable and oxygen-permeable substrate, a polyether sulfone plastic film having a thickness of 200 μm was used.

FIG. 3 is a graph showing moisture permeability characteristics when a glass substrate is applied as a material to be measured to the measuring apparatus shown in FIGS. 1 and 2 (a) and a plastic substrate (b) having no protective layer formed thereon. Is shown.

In FIG. 3, the x-axis represents elapsed time, and the y-axis represents a degree of decrease in current, that is, a decrease in height of calcium during continuous constant voltage application. The water vapor transmission rates of the glass substrate (a) and the plastic (b) are 10 ⁻⁶ g / m ² / day or less and 10 ¹ g / m ² / day, respectively, and are represented in parallel on the x and y axes on the graph, This proves that the device according to the invention is very suitable for measuring the water vapor transmission rate from 10 ¹ g / m ² / day to 10 ⁻⁶ g / m ² / day. In addition, the inset graph of FIG. 3 illustrates a degree of reduction in calcium height measured by varying time ranges when a plastic substrate is applied as a measurement target material.

Moisture permeability  Measure

As the protective layer, an organic-inorganic thin film made of an inorganic material and an organic material was used. As the inorganic material, a silicon oxide layer was laminated at a thickness of 50 nm, and the organic material was an acrylic resin laminated at a thickness of 50 nm.

The water vapor transmission characteristics for the case where the protective layer of the above embodiment is formed on the plastic substrate (c) and on the upper and lower surfaces of the plastic substrate (d) are shown in FIG. 4.

It can be seen from the results of FIG. 4 that the protective layer is formed on both the upper and lower surfaces of the plastic substrate to have a better moisture-proof effect, and in the case of (c) and (d), the moisture permeability of Equation 2 is shown. The measurement formula shows that it has a water vapor transmission rate of 10 ⁻¹ g / m ² / day and 10 ⁻³ g / m ² / day.

According to the present invention, by using the principle that the electrical characteristics of the measuring device is changed as the protective layer is breathable or oxygen permeable, it is not influenced by the reflectivity or transmittance of the protective layer, and is applicable to various organic electronic device protective layer processes. Unlike the prior art, there is no need to perform averaging of defects on the calcium layer inside the device, and a highly reliable moisture permeability and oxygen permeability measuring device for an organic electronic device protective layer and a measuring method using the device Can be provided.

Claims (9)

Glass substrates; A pair of electrode layers oppositely stacked on the glass substrate; A calcium layer laminated on the glass substrate; A moisture-permeable and oxygen-permeable substrate stacked on the calcium layer; A measurement target organic electronic device protective layer stacked on the moisture permeable and oxygen permeable substrate; And It includes a sealing material applied along the outer periphery of the measurement target organic electronic device layer, One end of the electrode layer is embedded in the calcium layer, the other end is the moisture permeability and oxygen permeability measuring device of the organic electronic device protective layer, characterized in that electrically connected to the external resistance measuring device. The apparatus of claim 1, wherein the electrode layer is an Ag material layer or an Au material layer. The apparatus of claim 1, wherein the calcium layer has a lamination thickness of about 50 nm to about 500 nm. The moisture permeability of the organic electronic device protective layer according to claim 1, wherein the moisture-permeable and oxygen-permeable substrate is a plastic selected from the group consisting of polyethylene, polypropylene, polystyrene, polyether sulfone, and polycarbonate, or a synthetic resin substrate using the same. And oxygen content measuring device. The device of claim 1, wherein the sealing material is a UV curable epoxy resin. Laminating a protective object organic electronic device protective layer on the moisture permeable and oxygen permeable substrate of the device according to any one of claims 1 to 5; Measuring a change in resistance value over time while applying a voltage to one end of the electrode layer of the device through the external resistance measuring device; Measuring the change in height over time of the calcium layer by substituting the measured resistance into Equation 1; And The moisture permeability and oxygen permeability of the protective layer of organic electronic device comprising the step of measuring the change in the height of the calcium layer in the following equation (2) and (3) to measure the moisture permeability and oxygen permeability of the protective target organic electronic device layer. How to measure: <Equation 1>

<Equation 2>

<Equation 3>

In Equations 1 to 3, Δh is the change in height of the calcium layer (the height of the reacted calcium layer), R is the resistance value of the calcium layer, R _i is the initial resistance value of the calcium layer, and h _i is the initial height of the calcium layer (the amount of deposited calcium Height), M (H ₂ O) is the molecular weight of water, M (Ca) is the molecular weight of calcium, M (O ₂ ) is the molecular weight of oxygen, δ is the density of calcium, and Δhr is the elapsed time. . The method of claim 6, wherein the voltage application range through the external resistance measuring device is in the range of 0.1 mV to 20 mV. The method of claim 6, wherein the moisture permeability and the oxygen permeability of the protective layer of the organic electronic device are measured based on the amount of change in resistance over time of the moisture permeable and oxygen permeable substrate and the amount of change in resistance over time on a glass substrate. Method for measuring the moisture permeability and oxygen permeability of the organic electronic device protective layer characterized in that it further comprises a step. The method of claim 6, wherein the organic electronic device is selected from the group consisting of an organic light emitting device, an organic thin film transistor, and an organic capacitor.

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