KR102614071B1 - Organic Light Emitting Display Device - Google Patents

Abstract

The present invention relates to an organic light emitting display device that prevents direct reflection of external light and improves the transmission effect of internal light by changing the surface structure of the substrate. The present invention relates to an organic light emitting display device, which has an inner surface of the second substrate facing at least one sub-pixel, It is provided with a scattering unit made of a plurality of irregularities.

Description

Organic Light Emitting Display Device

The present invention relates to a display device, and more particularly to an organic light emitting display device that prevents direct reflection of external light and improves the transmission effect of internal light by changing the surface structure of the substrate.

Specific examples of display devices include Liquid Crystal Display device (LCD), Organic Emitting Display Device, Plasma Display Panel device (PDP), and Quantum Dot Display Device. , Field Emission Display device (FED), and Electrophoretic Display Device (EPD), etc., which commonly have a flat display panel that implements images as an essential component. The display panel has a structure in which a pair of transparent insulating substrates are bonded together with an inherent light-emitting, polarizing, or other optical material layer in between.

Among these, organic light emitting display devices that can be lightweight by omitting a light source and have rich color expression are currently attracting attention.

Meanwhile, an organic light emitting display device includes an organic light emitting diode in each sub-pixel to emit light. The organic light emitting diode includes first and second electrodes facing each other and an organic light emitting layer between them. However, one of the first and second electrodes is used as a reflective electrode, but a problem is pointed out that external light is reflected by the reflective electrode and is perceived by the viewer as a defect.

The present invention is intended to solve the above-mentioned problems and proposes an organic light emitting display device that prevents direct reflection of external light and improves the transmission effect of internal light by changing the surface structure of the substrate.

The organic light emitting display device of the present invention changes the shape of the substrate surface to prevent reflection effects from external light and improve the efficiency of internal light coming from the organic light emitting diode.

For this purpose, an organic light emitting display device according to an embodiment of the present invention includes a first substrate having a plurality of sub-pixels, a first electrode sequentially stacked on the plurality of sub-pixels on the first substrate, and an organic light-emitting layer. and an organic light emitting diode including a second electrode, a second substrate facing the first substrate, a scattering portion made of a plurality of irregularities on an inner surface of the second substrate facing at least one sub-pixel, and the first substrate facing the first substrate. It includes an adhesive layer filled between one substrate and the second substrate.

A color filter may be provided on the inner side of the second substrate to correspond to a sub-pixel where the scattering portion is not located.

In the scattering unit, the average thickness of the second substrate is preferably smaller than the average thickness of the second substrate on which the scattering unit is not located.

It is preferable that the plurality of irregularities of the scattering portion have an irregular shape.

Meanwhile, the plurality of sub-pixels may include a red sub-pixel, a green sub-pixel, a blue sub-pixel, and a white sub-pixel. In this case, the scattering unit may be located opposite the white sub-pixel, and a color filter layer may be provided opposite the red sub-pixel, green sub-pixel, and blue sub-pixel, respectively.

Additionally, a scattering portion may be further included between the color filter layers.

Meanwhile, a bank dividing the sub-pixels may be further included on the first substrate. In this case, the scattering portions between the bank and the color filter layer may face each other.

The organic light emitting display device of the present invention has the following effects.

By providing a scattering portion made of irregular irregularities on the inner surface of the upper substrate, external light is scattered by the scattering portion, thereby preventing external light such as sparkles from being recognized as direct light. At the same time, when the light emitted from the internal organic light-emitting diode passes directly through the irregularities of the scattering portion, it is not totally reflected but is transmitted, thereby increasing the efficiency of using the internal light.

In particular, the organic light emitting display device of the present invention can reduce direct reflection of external light and minimize light loss of internal light by providing a scattering part in the white sub-pixel, which is severely affected by incident external light. Additionally, in the white sub-pixel, the roughness of the inner and outer surfaces of the upper substrate can be changed to increase the transmittance of internal light, thereby improving luminous efficiency.

1 is a cross-sectional view schematically showing an organic light emitting display device of the present invention.
Figure 2 is a cross-sectional view showing the configuration of the second substrate of the organic light emitting display device of the present invention.
Figure 3 is a diagram showing internal light transmission and external light scattering corresponding to the configuration of the scattering unit of Figure 2.
Figure 4 is a graph showing the intensity of internal light and external light by wavelength in the scattering part of Figure 2
Figures 5a to 5d are optical photographs of the shape of the scattering area according to the number of sandpapers.
6 is a cross-sectional view showing the organic light emitting display device of the present invention in detail.

The advantages and features of the invention and methods for achieving them will become clear by referring to the various embodiments described in detail below in conjunction with the accompanying drawings. However, the present invention is not limited to the various embodiments disclosed below and will be implemented in various different forms. The various embodiments of the present invention only serve to ensure that the disclosure of the present invention is complete and will be used in the technical field to which the present invention pertains. It is provided to fully inform those skilled in the art of the scope of the invention. Accordingly, the invention is defined by the scope of the claims.

The shapes, sizes, proportions, angles, numbers, etc. disclosed in the drawings for explaining various embodiments of the present invention are illustrative, and the present invention is not limited to the matters shown in the drawings. Like reference numerals refer to like elements throughout this specification. Additionally, in describing the present invention, if it is determined that a detailed description of related known technologies may unnecessarily obscure the gist of the present invention, the detailed description will be omitted. When 'includes', 'has', 'consists of', etc. mentioned in this specification are used, other parts may be added unless 'only' is used. When a component is expressed in the singular, the plural is included unless specifically stated otherwise.

In interpreting the components included in various embodiments of the present invention, it is interpreted to include a margin of error even if there is no separate explicit description.

In explaining various embodiments of the present invention, when describing positional relationships, for example, 'on top', 'on top', 'on bottom', 'next to', etc. When the positional relationship of parts is described, one or more other parts may be located between the two parts, unless 'immediately' or 'directly' is used.

In explaining various embodiments of the present invention, when explaining temporal relationships, for example, temporal relationships such as 'after', 'after', 'after', 'before', etc. When described, non-contiguous cases may be included unless 'immediately' or 'directly' is used.

Each of the features of the various embodiments of the present invention can be partially or entirely combined or combined with each other, various technical interconnections and operations are possible, and each of the various embodiments may be implemented independently of each other or together in a related relationship. It may be possible.

1 is a cross-sectional view schematically showing an organic light emitting display device of the present invention.

As shown in FIG. 1, the organic light emitting display device of the present invention includes a first substrate 100 having a plurality of sub-pixels, and organic light-emitting diodes (OLEDs) provided in each of the plurality of sub-pixels on the first substrate 100. 120), a second substrate 200 facing the first substrate 100, and a plurality of irregularities 200a located on the inner surface of the second substrate 200 facing at least one sub-pixel. It includes a scattering portion 200 made of and an adhesive layer 300 filled between the first substrate 100 and the second substrate 200.

In FIG. 1 , an unexplained reference numeral '130' that protrudes from the organic light emitting diode 120 and has a shape that partially penetrates the surface of the organic light emitting diode 120 is referred to as a 'bank' or 'protrusion'. This divides the light-emitting area of each sub-region and defines the light-emitting area of the organic light-emitting diode for each sub-region.

In addition, below the organic light emitting diode 120, a thin film transistor array 110 electrically connected to the organic light emitting diode 120 is located on the first substrate 100. The thin film transistor array 110 may include two or more thin film transistors and one or more capacitors in at least each sub-pixel, and one of the thin film transistors is electrically connected to the organic light emitting diode 120. In this case, the thin film transistor connected to the organic light emitting diode 120 is called a driving thin film transistor.

As will be described later in the drawings, the organic light emitting diode 120 is formed by sequentially stacking a first electrode, an organic light emitting layer, and a second electrode, and the bank 130 is formed before forming the organic light emitting layer. As shown in 1, the formation surface of the bank 130 may be above the first electrode, and may be located above a portion of the components forming the organic light emitting diode 120. However, the present invention is not limited to this, and the formation surface of the bank 130 may be in contact with the surface of the thin film transistor array 110 below. In some cases, a first electrode may be located inside the bank 130.

The organic light emitting diode 120 emits white light upward, and for this purpose, the first electrode may be a reflective electrode and the second electrode may be a transparent electrode. In addition, the organic light-emitting layer may include a single organic light-emitting layer that emits white light, or may have a stacked structure that includes a plurality of stacked organic light-emitting layers of different colors and mixes the light coming from them to emit white light. In addition, a common layer for transport of electrons and holes may be further provided on the top and bottom of the organic light emitting layer.

And, on the second substrate 200, color filters 210a, 210b, and 210c are provided on the inner surface of the second substrate 200, corresponding to sub-pixels in which the scattering unit 220 is not located. You can. The color filters 210a, 210b, and 210c may be color filters of different colors. For example, the first to third color filters 210a, 210b, and 210c may be red, green, and blue color filters, respectively. there is. However, it is not limited to the illustrated colors, and a color filter layer with a different color combination may be provided as long as white can be displayed by mixing light from the provided color filters.

These color filters (210a, 210b, 210c) serve to selectively transmit white light coming from the bottom in the color of the corresponding color filter (210a, 210b, 210c) for each sub-pixel, and the color filters (210a, 210b, 210c) ) Sub-pixels corresponding to the scattering portion 220 where ) are not located transmit the lower white light as is.

Here, the scattering portion 220 is defined by having a plurality of irregularities on the inner surface of the second substrate 200, as shown, and when external light enters through the second substrate 200, the scattering portion 220 It scatters external light passing through the scattering unit 220 or prevents direct external light in a specific direction from being incident on the second substrate 200. This prevents external direct light from being reflected from the reflective electrode of the organic light emitting diode, for example, the second electrode, causing sparkle.

In addition, the scattering unit 220 allows light emitted from the organic light emitting diode 120 to meet the irregularities of the scattering unit 220, and increases the amount of light extraction due to the irregular texture effect of the irregularities, thereby increasing the amount of external light. Improves emission efficiency.

Here, the area where the scattering unit 220 is located uses the internal light emitted from the organic light emitting diode 120 located on the first substrate 100 side without an additional filter, and corresponds to a white sub-pixel.

Also, in the scattering unit 220, the average thickness of the second substrate 200 is preferably smaller than the average thickness of the second substrate 200 of other sub-pixels where the scattering unit is not located. This is because the scattering part 220 has some of its thickness irregularly removed through physical or chemical etching to make the surface uneven, and the inner surface of the other flat sub-pixel where the first to third color filters 210a, 210b, and 210c are located. The thickness of the second substrate 200 is lower than that of the second substrate 200.

Meanwhile, in the drawing, the first to third color filters 210a, 210b, and 210c are shown as having a high center and low edges, but the first to third color filters 210a, 210b, and 210c are It may have the same thickness without deviation in the center and at the edges.

In addition, the adhesive layer 300 is cured after bonding between the first and second substrates 100 and 200, and is made of a heat or UV curable material. The refractive index in the cured state may be different from that of the second substrate 200.

FIG. 2 is a cross-sectional view showing the configuration of the second substrate of the organic light emitting display device of the present invention, and FIG. 3 is a diagram showing internal light transmission and external light scattering corresponding to the configuration of the scattering portion of FIG. 2.

2 and 3, in the second substrate 200 on which external light is directly incident and internal light is emitted, the sub-pixels on which the color filter layers 210a, 210b, and 210c are located are the color filter layers 210a, 210b, Due to the selective transparency for each wavelength of 210c), external light and wavelength bands other than those transmitted by the color filter layers 210a, 210b, and 210c are blocked. Accordingly, the sub-pixels where the color filter layers 210a, 210b, and 210c are located are hardly affected by direct light reflection. However, in the case of a white sub-pixel without a color filter layer, if the second substrate 200 is maintained with both inner and outer surfaces being flat, external light enters directly and is reflected on the reflective electrode of the organic light-emitting diode, making it visible to the viewer. There is a high risk of becoming This appears as a glint-like visibility defect when the viewer turns in a specific direction.

The organic light emitting display device of the present invention is provided with a scattering portion 220 having a plurality of irregularities in a white sub-pixel without a color filter layer on the inner surface of the second substrate 200 from which light is emitted, thereby emitting external light. By scattering in the scattering unit 220, external light is prevented from entering in one direction and causing direct light reflection. In addition, external light incident on the opposite side of the scattering unit 220 is significantly scattered and reflected in the scattering unit 220 due to glare reflection and is reduced, thereby preventing the external light from being transmitted to the organic light emitting diode in one direction. .

In this case, in the case of emitted light going from the bottom to the top, the extraction efficiency of the internal light can be increased by improving the extraction effect in the scattering unit 220. In addition, the light incident on the scattering unit 220 passes from the adhesive layer 300 through the scattering unit 220 to the second substrate 200, and when passing through media with different refractive indices, the light incident angle is varied. Light extraction efficiency can be increased by allowing light to be transmitted to the outer surface of the second substrate 200 in various directions within the second substrate 200.

Figure 4 is a graph showing the intensity of internal light and external light by wavelength in the scattering part of Figure 2.

4 shows, as shown in FIG. 3, the inner surface of the second substrate 200 is sanded 220, 600, and 1000 times, respectively, and the scattering part 220 is provided, and internal light (internal light) and external light (external light) are generated. The transmittance of light is measured by wavelength. The measured wavelength was measured only in the visible light range, which is perceptible to the human eye.

As shown in Figure 4, it was confirmed that the transmitted light intensity of internal light was greater than that of external light for each number of sandpaper types. In addition, it can be seen that as the number of sandpapers increases, the transmitted light intensity of the surface for external and internal light increases. This means that as the number of sandpapers increases, the size of the unevenness of the scattering area becomes smaller and the surface of the scattering area 220 becomes smoother. It is believed to occur.

Figures 5a to 5d are optical photographs showing the shape of the scattering area according to the number of sandpaper types.

Figures 5a to 5d show the states in which the number of sandings was 220, 600, 1000, and 2000 times, respectively, showing that the surface becomes smoother as the number of sandings increases.

Meanwhile, the light scattering and reflection characteristics can be adjusted to the degree of surface roughness of the scattering unit 220. Approximately, the size (diameter and height) of each irregularity 220a of the scattering unit 220 is within the visible light wavelength range to be transmitted. With the above, it is possible to improve efficiency without loss of emission of internal light and at the same time prevent reflection of external light. If both the inner and outer sides of the second substrate in the white sub-pixel are smooth, the glare reflection phenomenon will intensify, and if the size of the irregularities 220a is so fine that it is nano-sized, the surface is as if it were flat, and the transmittance of external light increases, preventing scattering. Since it does not occur effectively and direct external light reflection cannot be resolved, it is set to the visible light wavelength range or higher. In addition, the individual irregularities 220a are formed so that both the diameter and height do not exceed 6㎛ in order to sufficiently prevent reflection of external light without loss of internal light emission. If the size of the irregularities 220a is too large, the directivity of the emitted light may occur and be visible, and this is to prevent this. That is, the diameter of the individual irregularities 220a is set to be in the range of 380 nm to 6 ㎛ or less, and the height is set to be smaller than the above diameter.

In addition, it is preferable that the irregularities of the scattering unit 220 are arranged irregularly. If the irregularities have a certain regularity, the emitted light can be seen in different colors at different viewing angles due to the diffraction grating effect. Therefore, it is preferable that the irregularities 220a of the scattering portion 220 are irregular. That is, the diameter and height of the plurality of irregularities 220a may each be different. More specifically, in the three adjacent irregularities 220a, at least one must have a different shape (diameter or height) to reduce the diffraction grating effect caused by the repeated pattern.

Meanwhile, as described above, the scattering portion 220 can be formed using a material method such as sanding, or a chemical method using an etchant. In the case of a chemical method, an etchant is formed by diluting a material that can dissolve the substrate, such as HF, in a solvent such as water, and the etchant is supplied at a speed above a certain level to irregularly break the molecular bonds on the surface of the substrate. Forms irregularities.

Figure 6 is a cross-sectional view showing the organic light emitting display device of the present invention in detail.

As shown in Figure 6, the organic light emitting display device of the present invention specifically includes a first substrate 100 on which first to fourth sub-pixels (R-sub, G-sub, B-sub, W-sub) are regularly arranged. and a thin film transistor array having a pixel circuit unit including a driving thin film transistor (D-TFT) provided in each sub-pixel (R-sub, G-sub, B-sub, W-sub) on the first substrate 100. (110), an organic light emitting diode (120) electrically connected to the driving thin film transistor (D-TFT) and each sub-pixel (R-sub, G-sub, B-sub, W-sub), and each of the A second substrate 200 having a color filter layer (210a, 210b, 210c) or a scattering portion 220 facing the sub-pixels (R-sub, G-sub, B-sub, W-sub), and It includes an adhesive layer 300 filled between the first substrate 100 and the second substrate 200.

The driving thin film transistor (D-TFT) includes, for example, a semiconductor layer 101, a gate electrode 102 formed on a gate insulating film 104 covering the semiconductor layer 102, and the semiconductor layer 101. It includes a source electrode (103a) and a drain electrode (103b) connected to both ends. The illustrated driving thin-film transistor (D-TFT) is formed by using the semiconductor layer 101 as, for example, polysilicon. The semiconductor layer 101 is not limited to this, and the semiconductor layer 101 is an oxide semiconductor, an amorphous silicon layer, or an amorphous silicon layer. It can be changed into various forms, such as the form of a stack of polysilicon. In addition, the stacking form of the driving thin film transistor (D-TFT) can also be changed to a top gate structure, unlike the bottom gate shown, or a structure that uses both bottom gate and top gate.

In addition, the thin film transistor array 110 includes the driving thin film transistor (D-TFT) described above, and an interlayer insulating film 105 located between the gate electrode 102 and the source electrode 103a and the drain electrode 103b. , and further includes an inorganic protective film 106 and an organic protective film 107 that sequentially cover the source electrode 103 and the drain electrode 103b.

Meanwhile, the organic protective film 107 and the inorganic protective film 106 are provided with a contact hole (CT1) exposing a portion of the drain electrode 103b, so that the first electrode 122 of the organic light emitting diode is connected to the lower drain. It is connected to the electrode 103b.

In addition, the organic light emitting diode 120 includes a first electrode 122 including at least one layer of a reflective electrode, an organic light emitting layer 123 that emits white light, and a transparent second electrode 124 on the organic light emitting layer 123.

Here, the first electrode 122 is separated for each sub-pixel, and a bank 121 is provided by partially overlapping the edge of the first electrode 122.

The bank 121 may be omitted depending on the case, and as shown, may overlap with the first electrode 122, or the first electrode 122 may be located within the bank 121.

Color filters of different colors can be placed in the first to third sub-pixels (R-sub, G-sub, and B-sub) as red, green, and blue color filter layers (210a, 210b, and 210c), respectively. , a black matrix layer may be located between the first to fourth sub-pixels (R-sub, G-sub, B-sub, and W-Sub).

In addition, the bank 121 may be made of a black organic material. In this case, color mixing of light generated from adjacent sub-pixels can be prevented, and the black matrix layer described above can be omitted and its function can be replaced.

In some cases, the color filter layers 210a, 210b, and 210c may not be spaced apart, but may be formed by contacting or overlapping adjacent sub-pixels. The effect of preventing external light in overlapping areas can be further improved.

Alternatively, the scattering portion 220 may be disposed in the spaced apart portion between the color filter layers 210a, 210b, and 210c without the black matrix layer. In this case, it will be possible to prevent direct reflection of external light from the scattering unit 220 and improve the internal light emission effect described above. Here, the scattering portions 200 between the bank 121 and the color filter layers 210a, 210b, and 210c may face each other.

Meanwhile, the adhesive layer 300 filled between the first and second substrates 100 and 200 is transparent and is made of a material that does not affect the transmission of white internal light. Additionally, the adhesive layer 300 may be a material that is hardened after the first and second substrates 100 and 200 are bonded together and has a refractive index lower than that of the second substrate 200 and higher than that of air in the cured state. When external light enters the second substrate 200, the large refractive index difference (n2-n1) between the air and the second substrate 200 (refractive index of the second substrate: n2, refractive index of air: n1) causes the scattering. In the portion 220, some of the external light has an incident angle lower than the critical angle, so some total reflection occurs within the second substrate 200, but when internal light is emitted, the refractive index difference (n2-) between the adhesive layer 300 and the second substrate 200 n3) (refractive index of the adhesive layer: n3) is small, and the angle of incidence is varied in the scattering part 220 compared to a flat surface, so a total reflection condition does not occur and it can be used for almost all emission, so it can be used for light emission compared to external light. The light emission effect is good.

In particular, the organic light emitting display device of the present invention can reduce direct reflection of external light and minimize light loss of internal light by providing a scattering part in the white sub-pixel, which is severely affected by incident external light. Additionally, in the white sub-pixel, the roughness of the inner and outer surfaces of the upper substrate can be changed to increase the transmittance of internal light, thereby improving luminous efficiency.

Although embodiments of the present invention have been described in more detail with reference to the accompanying drawings, the present invention is not necessarily limited to these embodiments, and may be modified and implemented in various ways without departing from the technical spirit of the present invention. . Accordingly, the various embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention, but are for illustrative purposes, and the scope of the technical idea of the present invention is not limited by these embodiments. Therefore, the various embodiments described above should be understood in all respects as illustrative and not restrictive. The scope of protection of the present invention should be interpreted in accordance with the claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of rights of the present invention.

100: first substrate 110: thin film transistor array
120: organic light emitting diode 121, 130: bank
122: first electrode 123: organic light-emitting layer
124: second electrode 200: second substrate
210a, 210b, 210c: color filter layer 220: scattering area
220a: unevenness 300: adhesive layer

Claims (10)

A first substrate having a plurality of sub-pixels;
An organic light emitting diode including a first electrode, an organic light emitting layer, and a second electrode sequentially stacked on the plurality of sub-pixels on the first substrate;
a second substrate facing the first substrate;
a scattering portion formed of a plurality of irregularities on an inner surface of the second substrate facing at least one sub-pixel;
an adhesive layer filled between the first substrate and the second substrate; and
a color filter corresponding to a sub-pixel in which the scattering portion is not located and in contact with an inner surface of the second substrate;
Each of the plurality of convexities and convexities has a convex portion as an inner plane portion of the second substrate, and a concave portion having a groove shape that goes inward from the inner plane portion of the second substrate,
In the scattering portion, the average thickness of the second substrate is smaller than the average thickness of the second substrate on which the scattering portion is not located.
delete delete According to clause 1,
The organic light emitting display device wherein each of the plurality of irregularities has a diameter of 380 nm to 6 ㎛ or less, and a height of each of the plurality of irregularities is smaller than the diameter. According to clause 4,
The organic light emitting display device wherein the plurality of irregularities of the scattering portion have an irregular shape, with at least one of the three adjacent irregularities having a different diameter or height. According to clause 1,
The plurality of sub-pixels include a red sub-pixel, a green sub-pixel, a blue sub-pixel, and a white sub-pixel. According to clause 6,
The scattering portion is located opposite the white sub-pixel,
An organic light emitting display device comprising a color filter layer opposite the red sub-pixel, green sub-pixel, and blue sub-pixel. According to clause 7,
An organic light emitting display device further comprising a scattering portion between the color filter layers. According to clause 7,
The organic light emitting display device further includes a bank dividing the sub-pixels on the first substrate. According to clause 9,
An organic light emitting display device in which a scattering portion between the color filter layers and the bank face each other.