KR20090021714A - Organic light emitting diode - Google Patents

Abstract

An organic electroluminescent device having spacer is provided to improve uniformity of an electrode in forming a metal electrode layer inside a sub pixel by forming a spacer into a tapered shape. An organic electroluminescent device comprises a plurality of sub pixels(120), an insulated film, and a spacer(140). A plurality of sub pixels is arranged on a substrate into a matrix shape. The insulated film divides a plurality of sub pixels. The spacer has a tapered shape, and crosses a row between a plurality of sub pixels on the insulated film. Width ratio between the insulated film and the spacer is 1 : 0.3 ~ 0.9. Width(z) of the insulated film is 25um ~ 55um in case a plurality of sub pixels is emitted to a substrate direction. The width of the insulated film is 8um ~ 25um in case a plurality of sub pixels is emitted to an opposite direction of the substrate. Width(x) of the spacer is 16um ~ 30um.

Description

Organic Light Emitting Diode

The present invention relates to an organic electroluminescent device.

An organic light emitting display device used in an organic light emitting display device is a self-light emitting device in which a light emitting layer is formed between two electrodes positioned on a substrate.

In addition, the organic light emitting display device has a top emission method and a bottom emission method according to a direction in which light is emitted. This is divided into a passive matrix type and an active matrix type according to the driving method.

In general, organic light emitting diodes are fabricated through an anode patterning process, an insulating film process, organic material and cathode deposition, and a passivation and encapsulation process on a substrate.

In this manufacturing process, a spacer capable of performing various purposes such as a supporting role of the metal mask and a supporting member of the sealing member is formed on the substrate. In addition, the spacer can also achieve the purpose of preventing stress due to external air or external pressure, etc., and the frequency of applying the spacer is gradually increasing.

Meanwhile, as described above, although the various objects can be achieved, the conventional spacers have not been clearly formed to improve the purpose or effect of use.

As a result, during the manufacturing process, the mask applies an impact or scratch to the organic light emitting layer in the subpixel, causing a problem of increasing the defect rate or deteriorating the uniformity of the deposited thin film.

An object of the present invention for solving the above problems of the background art is to provide a spacer that can effectively perform a variety of purposes in the manufacturing process of the organic light emitting device to improve the production yield as well as to improve the reliability.

The present invention as a means for solving the above problems, the present invention comprises: a plurality of subpixels positioned in a matrix form on a substrate; An insulating film for dividing a plurality of sub pixels; Provided is an organic electroluminescent device comprising a spacer positioned in a tapered shape so as to cross rows between a plurality of sub pixels on an insulating film, wherein a ratio of the width between the insulating film and the spacer is 1: 0.3 to 0.9.

When the plurality of subpixels emit light toward the substrate, the width of the insulating layer may range from 25 μm to 55 μm.

When the plurality of sub pixels emit light in a direction opposite to the substrate, the width of the insulating film may range from 8 μm to 25 μm.

The width of the spacer may range from 16 μm to 30 μm.

The width of the spacer may range from 6 μm to 16 μm.

The height of the insulating film may be higher than the height of the electrode layer adjacent to the lower portion of the insulating film.

The material of the spacer and the insulating layer may be the same or different.

The spacers are positioned in the form of bars to cross rows between subpixels, or are divided to be spaced apart from each other on the same line, and the divided spacers may have the same or different lengths.

Spacers may be located between rows between subpixels or with one or more rows empty.

The height from the bottom surface of the insulating film to the top surface of the spacer may range from 3 μm to 6 μm.

The plurality of subpixels may include one or more transistors, capacitors, and organic light emitting diodes positioned on the substrate.

The present invention is to provide a spacer that can effectively perform a variety of purposes in the manufacturing process of the organic light emitting device to improve the production yield as well as to improve the reliability.

1 is a schematic diagram of an organic light emitting display device according to an embodiment of the present invention.

The substrate 110 may be selected as a member for forming an element having excellent mechanical strength and dimensional stability. As the material of the substrate 110, a glass plate, a metal plate, a ceramic plate or a plastic plate (polycarbonate resin, acrylic resin, vinyl chloride resin, polyethylene terephthalate resin, polyimide resin, polyester resin, epoxy resin, silicone resin, fluorine) Resin, etc.) is mentioned.

Here, when the organic light emitting diode is a passive matrix type, the organic light emitting layer may be positioned between the anode and the cathode positioned on the substrate 110 in the subpixel 120.

On the other hand, when the organic light emitting diode is an active matrix type, the subpixel 120 may have an organic light emitting layer positioned between an anode and a cathode connected to a source or drain electrode of a driving transistor included in a transistor array on the substrate 110. Can be. Here, the transistor array may include one or more transistors and capacitors.

The red, green, and blue subpixels 120R, 120G, and 120B may be defined as one unit pixel. In the illustrated drawing, one subpixel 120 is represented as including only red, green, and blue. However, this is only an example of an embodiment, and the subpixel 120 may further include four or more light emitting colors such as white, and may emit other colors (for example, orange, yellow, etc.). have.

Here, the subpixel 120 may include at least an organic emission layer. The organic light emitting layer may further include at least one of a hole injection layer, a hole transport layer, an electron transport layer, or an electron injection layer. In addition, the organic emission layer may further include a buffer layer, a blocking layer, and the like to control the flow of holes or electrons between the anode and the cathode. It may be.

On the other hand, the transistor can be largely divided into a switching transistor for switching the scan signal and a driving transistor for driving the data signal.

In addition, the organic light emitting display device may display a desired image by emitting light of a sub-pixel selected by a data signal and a scan signal supplied from the outside.

Hereinafter, the cross-sectional structure will be described in more detail with an example that the sub-pixel is an active matrix type.

2 is a cross-sectional view of a subpixel.

Referring to FIG. 2, a buffer layer 111 may be located on the substrate 110. The buffer layer 111 may be formed to protect the thin film transistor formed in a subsequent process from impurities such as alkali ions flowing out of the substrate 110. The buffer layer 111 may use silicon oxide (SiO ₂ ), silicon nitride (SiNx), or the like.

The semiconductor layer 112 may be positioned on the buffer layer 111. The semiconductor layer 112 may include amorphous silicon or polycrystalline silicon obtained by crystallizing the same. Although not shown here, the semiconductor layer 112 may include a channel region, a source region, and a drain region, and the source region and the drain region may be doped with P-type or N-type impurities.

The gate insulating layer 113 may be positioned on the substrate 110 including the semiconductor layer 112. The gate insulating layer 113 may be selectively formed using silicon oxide (SiO ₂ ), silicon nitride (SiNx), or the like.

The gate electrode 114 may be positioned on the gate insulating layer 113 to correspond to the channel region of the semiconductor layer 112. The gate electrode 114 includes aluminum (Al), aluminum alloy (Al alloy), titanium (Ti), silver (Ag), molybdenum (Mo), molybdenum alloy (Mo alloy), tungsten (W), tungsten silicide (WSi). It may include any one of ₂ ).

An interlayer insulating film 115 may be positioned on the substrate 110 including the gate electrode 114. The interlayer insulating film 115 may be an organic film or an inorganic film, or may be a composite film thereof.

When the interlayer insulating film 115 is an inorganic film, the interlayer insulating film 115 may include silicon oxide (SiO ₂ ), silicon nitride (SiNx), or SOG (silicate on glass). On the other hand, the organic film may include an acrylic resin, a polyimide resin or a benzocyclobutene (BCB) resin. First and second contact holes 115a and 115b may be disposed in the interlayer insulating layer 115 and the gate insulating layer 113 to expose a portion of the semiconductor layer 112.

The first electrode 116a may be positioned on the interlayer insulating film 115. The first electrode 116a may be an anode and may include a transparent conductive layer such as indium tin oxide (ITO) or indium zinc oxide (IZO), and the first electrode 116a may have a stacked structure such as ITO / Ag / ITO. It can have

Source and drain electrodes 116b and 116c may be positioned on the interlayer insulating film 115. The source electrode and the drain electrode 116b and 116c may be electrically connected to the semiconductor layer 112 through the first and second contact holes 115a and 115b. A portion of the drain electrode 116c may be positioned on the first electrode 116a and electrically connected to the first electrode 116a.

The source and drain electrodes 116b and 116c may include a low resistance material to lower the wiring resistance. The source electrode and the drain electrode 116b and 116c may be a multilayer film made of Mo, Mo, Tungsten, MoW, Titanium, Al, or Al alloy. A multilayer structure of titanium / aluminum / titanium (Ti / Al / Ti) or molybdenum / aluminum / molybdenum (Mo / Al / Mo) or molybdenum tungsten / aluminum / molybdenum tungsten (MoW / Al / MoW) may be used. . However, the multilayer film is not limited thereto.

The transistor located on the ideal substrate 110 may include a gate electrode 114, a source electrode, and a drain electrode 116b and 116c, and a transistor array having a plurality of transistors and capacitors may be electrically connected to the following organic light emitting diodes. have. (However, the structure of the capacitor is omitted)

An insulating layer 117 exposing a portion of the first electrode 116a may be disposed on the first electrode 116a (eg, an anode). The insulating layer 117 may include an organic material such as benzocyclobutene (BCB) resin, acrylic resin, or polyimide resin.

The organic light emitting layer 118 may be disposed on the exposed first electrode 116a, and the second electrode 119 (eg, a cathode) may be positioned on the organic light emitting layer 118. The second electrode 119 may be a cathode for supplying electrons to the organic light emitting layer 118, and may include magnesium (Mg), silver (Ag), calcium (Ca), aluminum (Al), or an alloy thereof. have.

The organic light emitting diode connected to the source or drain electrodes 116b and 116c of the transistor array on the ideal substrate 110 includes a first electrode 116a, an organic light emitting layer 118, and a second electrode 119. can do.

However, the first electrode 116a positioned on the source electrode or the drain electrodes 116b and 116c of the transistor array may be positioned on a planarization film that planarizes the surface of the transistor array. In addition, the structure of the transistor array may vary depending on whether it is a top gate or a batam gate. In addition, their structures may vary depending on the number of masks and semiconductor layer materials used when forming the transistor array. Therefore, the structure of the subpixel is not limited thereto.

Referring back to FIG. 1, a spacer 140 may be positioned between a plurality of sub pixels 120 positioned in a matrix form on the substrate 110. The spacer 140 may be positioned to cross a row between the subpixels 120 in a bar shape. In detail, the spacer 140 may be positioned to pass between a subpixel located in an nth row and a subpixel located in an n + 1th row.

However, as shown in FIG. 1, the spacer 140 may not be positioned for each row between the subpixels 120, but may be positioned only in a row selected to leave one or more rows empty. In addition, the spacers 140 may be formed in the same shape or in the same pattern as the spacers positioned in other rows. In addition, the spacer 140 may be formed of a different material from the insulating layer 117 or may be formed of the same material. Here, when the spacer 140 and the insulating film 117 are the same material, the spacer 140 may have a form extending from the bottom of the insulating film 117.

Hereinafter, the cross-sectional structure of the spacer is attached and described in more detail.

3 is a cross-sectional view of the spacer.

Referring to FIG. 3, the spacer 140 used in the present invention may have a forward taper shape in which a lower portion of the spacer 140 facing the insulating layer 117 is wider than an upper portion thereof.

The spacer 140 having such a shape may serve to ensure that the metal electrode layer (eg, the cathode of the organic light emitting diode) formed on the spacer 140 is uniformly positioned within each sub-pixel. In addition, it may serve to prevent scratches caused by contact between the subpixel and the metal mask. To this end, the spacer 140 may have a regular taper shape having a taper angle r of 30 ° to 40 ° or less. In addition, the spacer 140 may serve as a structure that provides various advantages in the manufacturing process.

Meanwhile, since the overall shape of the spacer 140 may be determined based on the insulating film 117 disposed below the spacer 140, the width x of the spacer 140 may be equal to the width z of the insulating film 117. It can be formed in preparation. Here, the width z of the insulating film 117 may be defined as an upper surface of the insulating film 117. This is because the spacer 140 is formed on the upper surface of the insulating film 117. In addition, the width x of the spacer 140 may be defined as a lower surface of the spacer 140. This is because the spacer 140 has a regular tapered shape having a wide lower portion and a narrow upper portion.

Hereinafter, the relationship between the width of the insulating film and the width of the spacer will be described in more detail.

4 is a view for explaining the width of the insulating film and the width of the spacer.

The substrate 110 illustrated in FIG. 4 may be defined as light emitting regions B1 and B2 and non-light emitting regions y and z. The light emitting regions B1 and B2 may be defined as a plurality of subpixels 120 positioned in a matrix form, and the non-light emitting regions y and z may be defined as all regions other than the subpixels 120. Can be. In more detail, the light emitting regions B1 and B2 may be opening regions in which the organic light emitting layer is positioned in the subpixel 120, and the non-light emitting regions y and z are insulating layers in which an insulating material is formed in regions other than the openings. 117) an area.

An area corresponding to “y” in the non-light emitting areas y and z becomes an element for setting the row spacing between the subpixels 120. The region corresponding to "z" becomes an element for setting the column spacing between the subpixels 120. "y" and "z" become elements for setting the size and resolution of the subpixel.

Here, the region corresponding to "z" may be a region where the spacer 140 may be located. Accordingly, an element capable of setting the width x of the spacer 140 may be "z". That is, the width x of the spacer 140 may depend on the width z of the insulating layer positioned in the “z” region.

Meanwhile, the width x of the spacer 140 and the width z of the insulating layer may be 1: 1.1 to 2.8 times. As shown in these width ratios, it can be seen that the width z of the insulating film is wider than the width x of the spacer 140.

However, the width z of the insulating film and the width x of the spacer 140 may vary according to the light emitting method of the organic light emitting diode, and thus, the width z of the insulating layer and the top light emitting method of the insulating layer 140 will be described.

Batam light emitting method

For the sake of understanding, a batam light emitting organic electroluminescent device having a resolution of QVGA (320 × 240) class and a width z of an insulating film having a range of 25 μm to 55 μm will be described as an example.

As an example, it is assumed that the width z of the insulating layer is 25 μm and the width x of the spacer 140 is 15 μm. In this case, it can be seen that the ratio of the width z of the insulating film and the width x of the spacer 140 is 1.6: 1.

As another example, it is assumed that the width z of the insulating film is 45 μm and the width x of the spacer 140 is 25 μm. In this case, it can be seen that the ratio of the width z of the insulating film and the width x of the spacer 140 is 1.8: 1.

As another example, it is assumed that the width z of the insulating film is 54.5 μm and the width x of the spacer 140 is 20 μm. In this case, the ratio of the width z of the insulating film to the width x of the spacer 140 may be understood to be 2.72: 1.

[Top emission method]

For convenience of explanation, a top emission type organic light emitting display device having a resolution of QVGA (320 × 240) class and a width z of an insulating film having a range of 8 μm to 25 μm will be described as an example.

As an example, it is assumed that the width z of the insulating layer is 19 μm and the width x of the spacer 140 is 10 μm. In this case, it can be seen that the ratio of the width z of the insulating film and the width x of the spacer 140 is 1.9: 1.

As another example, it is assumed that the width z of the insulating film is 12 μm and the width x of the spacer 140 is 8 μm. In this case, it can be seen that the ratio of the width z of the insulating film and the width x of the spacer 140 is 1.5: 1.

As another example, it is assumed that the width z of the insulating film is 8 μm and the width x of the spacer 140 is 7 μm. In this case, it can be seen that the ratio of the width z of the insulating film and the width x of the spacer 140 is 1.14: 1.

The numerical range according to the above two light emission methods indicates that the width z of the insulating layer 117 and the width x of the spacer 140 may be differently formed according to the light emission method.

In the case of the batam emission method, since the light must be emitted toward the substrate in which the transistor array is located, the margin width should be large when the insulating layer 117 and the spacer 140 are designed. That is, in the case of the batam emission method, the transistor array positioned on the substrate may affect the size of the opening. Accordingly, the width z of the insulating film 117 of Batam emission type may have a range of 25 μm to 55 μm, and the width x of the spacer 140 is approximately 16 μm compared to the width z of the insulating film 117. It may have a range of ~ 30 ㎛.

In view of these numerical relationships, it can be seen that the ratio of the width x of the spacer 140 of the batam emission type to the width z of the insulating layer 117 may be approximately 1: 1.5 to 2.8 times. .

When the above ratio is described in terms of the spacer 140, the width x of the spacer 140 may have about 0.36 to 0.67 times the width z of the insulating layer 117.

Here, if the width (x) of the spacer 140 is formed in a range of 0.36 or more compared to the width (z) of the insulating film 117, the spacer 140 serves to support the metal mask with a minimum width during the deposition process. can do. In addition, the electrical characteristics and uniformity of the material (eg, aluminum) of the metal electrode layer (eg, the cathode of the organic light emitting diode) formed on the insulating layer 117 and the spacer 140 may be improved.

And, if the width (x) of the spacer 140 is formed to be within the range of 0.67 or less than the width (z) of the insulating film 117, the shadow phenomenon due to the width (x) of the spacer 140 during the deposition process can be prevented. have. In addition, the role of supporting the metal mask may of course be formed to be rigid enough to support the sealing member after the sealing process.

In the case of the top emission type, since light is emitted in a direction opposite to the substrate on which the transistor array is located, the margin width can be set small when the insulating layer 117 and the spacer 140 are designed. That is, in the top emission method, the transistor array positioned on the substrate may not affect the size of the opening. Accordingly, the width z of the top emission insulating layer 117 may range from 8 μm to 25, and the width x of the spacer 140 is approximately 6 μm to the width z of the insulating layer 117. It may have a range of 16 μm.

In view of these numerical relationships, it can be seen that the ratio of the width x of the spacer 140 of the batam emission type to the width z of the insulating layer 117 may be approximately 1: 1.1 to 1.6. All.

When the above ratio is described in terms of the spacer 140, the width x of the spacer 140 may have approximately 0.62 to 0.90 times the width z of the insulating layer 117.

Here, if the width (x) of the spacer 140 is formed in a range of 0.62 or more than the width (z) of the insulating film 117, the spacer 140 serves to support the metal mask with a minimum width during the deposition process. can do. In addition, the electrical characteristics and uniformity of the material (eg, aluminum) of the metal electrode layer (eg, the cathode of the organic light emitting diode) formed on the insulating layer 117 and the spacer 140 may be improved. As a result, the phenomenon in which charge is concentrated in the metal electrode layer can be prevented, and a phenomenon in which streaks appear on the screen can be prevented.

When the width x of the spacer 140 is formed to be 0.90 or less than the width z of the insulating layer 117, the shadow phenomenon due to the width x of the spacer 140 may be prevented during the deposition process. have. In addition, it is possible to prevent the occurrence of foreign matter in the openings of the subpixels. In addition, the role of supporting the metal mask may of course be formed to be rigid enough to support the sealing member after the sealing process.

The above has described numerically the ratio which can ensure the opening ratio of an organic light emitting layer by setting the width x of the spacer 140 with respect to the width z of the insulating film 117. As described above, when the insulating layer 117 and the spacer 140 are formed, the opening ratio may be improved by approximately 20% or more. However, the ratio relationship described above may further consider one or more of the height of the spacer 140, the resolution (area of the subpixel), or the material properties.

On the other hand, the present invention can be applied in various forms as well as the spacer 140 of FIG. Hereinafter, this will be described in more detail with reference to FIGS. 5A to 5C.

5A through 5C are schematic plan views of an organic light emitting display device according to another exemplary embodiment of the present invention.

First, referring to FIG. 5A, unlike FIG. 1, the spacer 140 is divided into bars in one row. Here, the spacers 140 may have a structure divided into the same or different lengths so as to be spaced apart from each other by a predetermined interval on the same line (on the same scan line). Here, the divided spacers may have the same or different lengths.

Such a structure can increase step-coverage when forming a metal electrode layer in the sub-pixel 120 as well as improve the uniformity of the electrode. In the structure of the divided spacer, the spacer 140 may be positioned to partially overlap the region of one first spacer positioned in the nth row and the region of one second spacer positioned in the n−1 th row. have. That is, the divided spacer 140 may be disposed in a zigzag form or a zigzag form on the substrate 110. When the divided spacer 140 is positioned in this manner, the metal mask may be prevented from sagging in a specific area.

In addition, referring to FIG. 5B, although the spacer 140 has a bar shape as shown in FIG. 1, it has a structure connected to each other by a connecting portion 140c connecting the end and the end of the spacer 140.

Such a structure can perform a role of preventing stress due to external pressure as well as a role of preventing moisture permeation by external air. In addition, when the encapsulation substrate is glass, the encapsulation substrate may be supported on all surfaces of the substrate 110.

In addition, referring to FIG. 5C, the spacer 140 having the same shape as that of FIG. 5A may also form a connection portion 140c to connect the end and the end of the spacer 140 to each other.

The spacer 140 as described above may use a black series to shield or absorb external light incident from the outside. That is, it can play a role similar to that of the black matrix.

The present invention is to provide a spacer that can effectively perform a variety of purposes in the manufacturing process of the organic light emitting display device to improve the production yield as well as to improve the reliability.

Although the embodiments of the present invention have been described above with reference to the accompanying drawings, the technical configuration of the present invention described above may be modified in other specific forms by those skilled in the art to which the present invention pertains without changing its technical spirit or essential features. It will be appreciated that it may be practiced. Therefore, the embodiments described above are to be understood as illustrative and not restrictive in all aspects. In addition, the scope of the present invention is shown by the claims below, rather than the above detailed description. Also, it is to be construed that all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts are included in the scope of the present invention.

1 is a schematic view of an organic light emitting display device according to an embodiment of the present invention.

2 is a cross-sectional view of a subpixel.

3 is a cross-sectional view of the spacer.

4 is a view for explaining the width of the insulating film and the width of the spacer.

5A to 5C are schematic views of an organic light emitting display device according to another embodiment of the present invention.

Floor plan.

<Explanation of symbols on main parts of the drawings>

110: substrate 117: insulating film

120: subpixel 140: spacer

Claims (11)

A plurality of subpixels positioned in a matrix form on the substrate; An insulating film for dividing the plurality of sub pixels; And a spacer positioned on the insulating layer in a regular tapered shape to cross rows between the plurality of subpixels. The ratio of the width between the insulating film and the spacer is an organic light emitting device is located 1: 1: 0.3. The method of claim 1, When the plurality of sub pixels emit light toward the substrate, The width of the insulating film has an organic light emitting device having a range of 25 ㎛ to 55 ㎛. The method of claim 1, When the plurality of sub pixels emit light in the opposite direction of the substrate, The width of the insulating film has an organic light emitting device having a range of 8 ㎛ to 25 ㎛. The method of claim 2, The width of the spacer, An organic light emitting display device having a range of 16 μm to 30 μm. The method of claim 3, The width of the spacer, An organic light emitting display device having a range of 6 μm to 16 μm. The method of claim 1, The height of the insulating film, And an organic light emitting device that is higher than the height of the electrode layer adjacent to the lower portion of the insulating film. The method of claim 6, The material of the spacer and the insulating layer is the same or different organic light emitting device. The method of claim 1, The spacer, Positioned in a bar shape to cross rows between the subpixels, The organic light emitting device is divided so as to be spaced apart from each other on the same line, and the divided spacers have the same or different lengths. The method of claim 1, The spacer, An organic light emitting diode positioned between rows of the subpixels or at least one row is left empty; The method of claim 6, An organic light emitting diode having a height from a lower surface of the insulating film to an upper surface of the spacer is in the range of 3 μm to 6 μm. The method of claim 1, The plurality of subpixels, An organic light emitting device comprising at least one transistor, a capacitor and an organic light emitting diode positioned on the substrate.

Images