CN105206758A - Organic light emitting diode display - Google Patents

Abstract

The invention discloses an organic light emitting diode display. The organic light emitting diode display is provided with a plurality of pixel regions and comprises a substrate, a first electrode layer, a second electrode layer, a pixel definition layer and a light absorption composite layer. The first electrode layer is formed on the substrate, and the second electrode layer is formed on the first electrode layer. The pixel regions are separated by a pixel definition layer. The light absorption composite layer is formed on the substrate, wherein the light absorbed by the light absorption composite layer has a wavelength range of about 380-780 nm. The light absorption composite layer comprises a first light absorption layer and a second light absorption layer, and the second light absorption layer is formed on the first light absorption layer. The first light absorption layer absorbs light with shorter wavelength and the second light absorption layer absorbs light with longer wavelength different from that absorbed by the first light absorption layer in the wavelength range of about 380-780 nm.

Description

Organic Light Emitting Diode Display

technical field

The present invention relates to an organic light emitting diode display, and in particular to an organic light emitting diode display with good suppression of lateral light leakage.

Background technique

Organic light-emitting diode (OLED) displays have the advantages of thin thickness, active light emission without backlight, and no viewing angle limitation. As consumers expect high display quality of electronic products, the image resolution of organic light-emitting diode displays must develop toward high-resolution pixels (HighPPI; HighPixelperInch).

However, in the process of manufacturing the light-emitting elements in the OLED display, due to variations in the manufacturing process conditions, etc., the panels display color unevenness, abnormality, side light leakage, or color shift. Therefore, research and development of organic light emitting diode displays with both high resolution and high display quality is one of the most important issues at present.

Contents of the invention

The object of the present invention is to provide an OLED display. In an organic light-emitting diode display, the light-absorbing composite layer formed by the first light-absorbing layer and the second light-absorbing layer can absorb the wavelength of light that can effectively cover the entire range of visible light, thus effectively preventing sideways between pixel regions. To prevent light leakage, thereby improving the color saturation and display effect of the display.

To achieve the above purpose, according to an embodiment of the present invention, an organic light emitting diode display is provided. The OLED display has a plurality of pixel areas and includes a substrate, a first electrode layer, a second electrode layer, a pixel definition layer and a light-absorbing composite layer. The first electrode layer is formed on the substrate, and the second electrode layer is formed on the first electrode layer. Pixel regions are separated by pixel definition layers. The light-absorbing composite layer is formed on the substrate, wherein the light absorbed by the light-absorbing composite layer has a wavelength range of about 380-780 nanometers. The light-absorbing composite layer includes a first light-absorbing layer and a second light-absorbing layer, and the second light-absorbing layer is formed on the first light-absorbing layer. The light absorbed by the first light absorbing layer has a shorter wavelength, and the light absorbed by the second light absorbing layer has a longer wavelength different from the light absorbed by the first light absorbing layer in the wavelength range of about 380-780 nanometers.

In order to have a better understanding of the above-mentioned and other aspects of the present invention, the preferred embodiments are specifically cited below, together with the accompanying drawings, and described in detail as follows:

Description of drawings

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

2 is a schematic diagram of an organic light emitting diode display according to another embodiment of the present invention;

3 is a schematic diagram of the relationship between the thickness of the first light-absorbing layer and the second light-absorbing layer relative to the average light transmittance according to an embodiment of the present invention;

4 is a schematic diagram of the relationship between the light emission wavelength range and the light transmittance of the first light absorbing layer according to an embodiment of the present invention;

5 is a schematic diagram of the relationship between the emission wavelength range and the light transmittance of the second light-absorbing layer according to an embodiment of the present invention;

6 is a schematic diagram of the relationship between the light emission wavelength range and the light transmittance of the light-absorbing composite layer according to an embodiment of the present invention;

FIG. 7 is a schematic diagram of the relationship between the thickness of the first light absorbing layer and the second light absorbing layer relative to the light absorbing rate according to an embodiment of the present invention.

Symbol Description

100, 200: OLED displays

110: Substrate

120: first electrode layer

130: second electrode layer

140: Pixel definition layer

140a: opening

150: light absorbing composite layer

151: first light absorbing layer

153: Second light absorbing layer

160: luminescent layer

I, II: curve

P: pixel area

Detailed ways

According to an embodiment of the present invention, in an organic light-emitting diode display, the light-absorbing composite layer formed by the first light-absorbing layer and the second light-absorbing layer can absorb light with wavelengths that can effectively cover the entire range of visible light, thereby effectively preventing The phenomenon of light leakage between pixel areas improves the color saturation and display effect of the display. Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The same reference numerals are used in the drawings to designate the same or similar parts. It should be noted that the drawings have been simplified to clearly illustrate the content of the embodiments, and the detailed structures proposed in the embodiments are for illustration purposes only, and are not intended to limit the scope of protection of the present invention. Those with ordinary knowledge can modify or change these structures according to the needs of actual implementation.

FIG. 1 is a schematic diagram of an OLED display 100 according to an embodiment of the present invention. As shown in FIG. 1 , the OLED display 100 has a plurality of pixel regions P. As shown in FIG. The OLED display 100 includes a substrate 110 , a first electrode layer 120 , a second electrode layer 130 , a pixel definition layer 140 and a light-absorbing composite layer 150 . The first electrode layer 120 is formed on the substrate 110 and disposed corresponding to the pixel region P, and the second electrode layer 130 is formed on the first electrode layer 120 . Each pixel region P is separated by a pixel definition layer 140 . The light-absorbing composite layer 150 is formed on the substrate 110 and at least corresponding to the pixel definition layer 140 . The light absorbed by the light-absorbing composite layer 150 covers the wavelength range of visible light, and the absorbed light has a wavelength range of 380-780 nanometers. The light-absorbing composite layer 150 includes at least a first light-absorbing layer 151 and a second light-absorbing layer 153, the first light-absorbing layer 151 absorbs light including the first wavelength range, and the second light-absorbing layer 153 is located in the first light-absorbing layer 151 and absorb light including the second wavelength range. Wherein, the first wavelength range is different from the second wavelength range, and both the first wavelength range and the second wavelength range cover at least part of the visible light wavelength range. The aforementioned different wavelength ranges mean that the wavelength ranges of light absorbed by the two are not exactly the same, so the wavelength ranges of light absorbed by the first light-absorbing layer and the second light-absorbing layer may partially overlap, adjoin or separate.

In an embodiment, the light transmittance of the first light absorbing layer 151 in the first wavelength range is, for example, 20-80%, and the light transmittance of the second light absorbing layer 153 in the second wavelength range is, for example, 20-80%. %.

In an embodiment, the first light-absorbing layer 151 can also absorb light with a second wavelength range, and the light transmittance of the first light-absorbing layer 151 in the first wavelength range is, for example, smaller than the light transmittance in the second wavelength range. transmittance.

In an embodiment, the second light absorbing layer 153 can also absorb light having a first wavelength range, and the light transmittance of the second light absorbing layer 153 in the first wavelength range is, for example, greater than the light transmittance in the second wavelength range. transmittance.

In an embodiment, the thicknesses of the first light-absorbing layer 151 and the second light-absorbing layer 153 may be respectively between 500-4000 angstroms.

In the embodiment, the organic light emitting diode display 100 is, for example, a white light organic light emitting diode display, the light of each pixel region P corresponds to a specific color block of the color filter, and the pixel regions P corresponding to different color blocks are connected to each other through the pixel Define layer 140 to separate. Since the light absorbed by the light-absorbing composite layer 150 has a wavelength range of about 380-780 nanometers, which covers the range of visible light, the light-absorbing composite layer 150 can absorb the light emitted from the pixel area P to the adjacent pixel area P, effectively The lateral light leakage phenomenon between the plurality of pixel regions P is prevented.

Compared with directly manufacturing a single-layer pixel definition layer or patterned mask layer, it is usually necessary to use an exposure and development process combined with an ultraviolet curing process to produce the pattern of the pixel definition layer or patterned mask layer. But in order for the pixel definition layer or the patterned mask layer to be curable by ultraviolet light, the material of the pixel definition layer or the patterned mask layer must be able to allow blue-violet light to pass through it to cure into the desired pattern . Therefore, the pixel definition layer or the patterned mask layer produced in this way cannot be pure black, and thus cannot absorb light covering the entire wavelength range of visible light. That is to say, such a single-layer pixel definition layer or patterned mask layer cannot absorb or block light in the entire visible wavelength range (380-780 nanometers), at least blue-violet light still has a chance to pass through, so the pixel The light between the regions still cannot be completely isolated, and the light leakage between the pixel regions cannot be effectively prevented.

In an embodiment, as shown in FIG. 1 , the first light-absorbing layer 151 is stacked on the second light-absorbing layer 153 and directly contacts the second light-absorbing layer 153 . In an embodiment, the first light-absorbing layer 151 absorbs light in a first wavelength range including shorter wavelengths, such as light in a range of 380-480 nanometers, which is the wavelength range of light in the blue-violet system. In other words, in this embodiment, the second light absorbing layer 153 absorbs the light in the second wavelength range with a wavelength range that at least covers the range of 480-780 nanometers. That is to say, through the first light-absorbing layer 151 and the second light-absorbing layer 153, the wavelength of light absorbed by the light-absorbing composite layer 150 can effectively cover the entire range of visible light, so the light-absorbing composite layer 150 can have the characteristics of pure black, All visible light can be absorbed, and lateral light leakage between multiple pixel regions can be effectively prevented. In this way, the purity of a single color in each pixel area P can be improved, and the color saturation of the display can also be improved, thereby improving the display effect.

Furthermore, by forming the light-absorbing composite layer 150 with the first light-absorbing layer 151 and the second light-absorbing layer 153, the light absorption of the two stacked film layers has an additive effect, which is higher than that of a single-layer structure. The light absorption is more helpful to isolate the light leakage between the pixel areas.

In an embodiment, at least one of the first light-absorbing layer 151 and the second light-absorbing layer 153 may include an organic material, such as a material commonly used in a hole transport layer, an emission layer and/or an electron transport layer. Compared with using polymer as the material of the first light-absorbing layer 151 and the second light-absorbing layer 153, a spin-coating process (spincoating process) is required during production, which is a wet-type production process, and there will be solvents or pollution in the production process. thing. In contrast, according to an embodiment of the present invention, small molecules or a small number of vapor-depositable high-molecular organic materials are used as the materials of the first light-absorbing layer 151 and the second light-absorbing layer 153, which can be produced through an evaporation process. This is a dry process, so there is no problem of solvents or pollutants, and there is relatively no problem of moisture, so the purity and quality of the first light-absorbing layer 151 and the second light-absorbing layer 153 can be improved. In addition, the first light-absorbing layer 151 and the second light-absorbing layer 153 fabricated by using organic materials through an evaporation process may have a smaller thickness, for example, 500˜4000 angstroms. In an embodiment, the thickness of the light-absorbing composite layer 150 is, for example, 4000 angstroms. When the existing first light-absorbing layer 151 and the second light-absorbing layer 153 are used as materials for the hole transport layer, light-emitting layer and/or electron transport layer, the thickness often needs to be made very thin to avoid the effect of absorbing light. , to avoid poor light extraction efficiency of the organic light-emitting element, so the thickness is often below 100 angstroms, and this embodiment uses its absorption properties as the material of the light-absorbing composite layer 150 , so it needs to have a certain thickness.

In an embodiment, at least one of the first light-absorbing layer 151 and the second light-absorbing layer 153 may include one of the following compounds or a combination of any two or more of them: (CuPc; wavelength range of absorbed light: 600-800 nm), (ZnPc; wavelength range of absorbed light: 600-700 nm), (SubPc; wavelength range of absorbed light: 450-600 nm), (SubNc; wavelength range of absorbed light: 500-750 nm), (Perylene), (PTCDA; wavelength range of absorbed light: 400-600 nm), (PTCDI; wavelength range of absorbed light: 400-600 nm), (P3HT; wavelength range of absorbed light: 400-650 nm), (PCBM; wavelength range of absorbed light: 300-600 nm), (DCJTB; wavelength range of absorbed light: 400-650 nanometers), Fe ₂ O ₃ (wavelength range of absorbed light: 300-600 nanometers).

Since each material has a different wavelength range of light absorption, the light-absorbing composite layer 150 can be made by using the first light-absorbing layer 151 and the second light-absorbing layer 153 to adjust the most suitable light-absorbing layer. wavelength range, and then fabricate a light-absorbing composite layer 150 with pure black characteristics.

In an embodiment, at least one of the first light absorbing layer 151 and the second light absorbing layer 153 may include a P-type dopant, such as F4-TCNQ.

In an embodiment, the first electrode layer 120 is, for example, an anode, and the second electrode layer 130 is, for example, a cathode. Wherein, the first electrode layer 120 is, for example, a reflective electrode layer.

In an embodiment, the OLED display 100 may further include a light emitting layer 160 formed on the substrate 110 and covering the pixel definition layer 140 and the first electrode layer 120, while the second electrode layer 130 is located on the substrate 110 And cover the light emitting layer 160 , that is, the light emitting layer 160 is located between the first electrode layer 120 and the second electrode layer 130 .

As shown in FIG. 1 , the light-absorbing composite layer 150 is formed between the substrate 110 , the first electrode layer 120 , and the pixel definition layer 140 . That is, the light-absorbing composite layer 150 is disposed corresponding to the plurality of pixel regions P and the pixel definition layer 140 . In an embodiment, the light-absorbing composite layer 150 of the OLED display 100 is a whole film layer, and the whole light-absorbing composite layer 150 is formed under the first electrode layer 120 . Since the light-absorbing composite layer 150 is formed at the bottom, in addition to absorbing the light emitted by the light-emitting layer 160 and entering the bottom through the pixel definition layer, the problem of lateral light leakage caused by light reflected at the bottom to adjacent pixels is also avoided. When the area of the pixel definition layer 140 is viewed from the outside, it will be seen as black, which can reduce the influence of the light reflected by the first electrode layer 120, increase the contrast when viewed outside, and increase the readability.

In addition, the light-absorbing composite layer 150 is a whole-surface film layer without a pattern corresponding to the pixel area P, so it does not need to be manufactured by precise photomask etching process, and it is not easy to cause defects caused by poor alignment accuracy. question.

FIG. 2 is a schematic diagram of an OLED display 200 according to another embodiment of the present invention. The components in this embodiment that are the same as those in the previous embodiments use the same component numbers, and for the related description of the same components, please refer to the above, and details will not be repeated here.

As shown in FIG. 2 , in this embodiment, the light-absorbing composite layer 150 is located on the pixel definition layer 140 . In detail, the light-absorbing composite layer 150 is only formed on the pixel definition layer 140 , and the pixel region P is exposed outside the light-absorbing composite layer 150 . In this embodiment, the light-absorbing composite layer 150 is formed between the light-emitting layer 160 and the pixel definition layer 140 . That is to say, the light-absorbing composite layer 150 of the OLED display 200 has the break opening 140a corresponding to the pattern of the pixel regions P, so that the light leakage between the pixel regions P can be isolated more effectively.

In yet another embodiment, the light-absorbing composite layer 150 of the OLED display may further include a third light-absorbing layer (not shown). The third light-absorbing layer is formed on the second light-absorbing layer 153, and the light absorbed by the third light-absorbing layer has a wavelength range different from that of the light absorbed by the first light-absorbing layer 151 and the wavelength of the light absorbed by the second light-absorbing layer 153. scope.

The following examples will be further described. In the following embodiments, taking the first light absorbing layer 151 comprising P-type dopant material and the second light absorbing layer 153 comprising CuPc as an example, FIG. 3 shows the first light absorbing layer 151 and the second The relationship between the thickness of the light-absorbing layer 153 and the average light transmittance; FIG. 4 shows the relationship between the light-emitting wavelength range and the light transmittance of the first light-absorbing layer 151 according to an embodiment of the present invention; FIG. 5 shows According to an embodiment of the present invention, the relationship between the emission wavelength range and the light transmittance of the second light-absorbing layer 153; FIG. The relationship of the transmittance; FIG. 7 shows the relationship of the thickness of the first light absorbing layer 151 and the second light absorbing layer 153 with respect to the light absorbing rate according to an embodiment of the present invention. However, the following examples are for illustrative purposes and should not be construed as limitations on the practice of the present invention. It should be noted that light transmittance and light absorbance have complementary properties, when the first light absorbing layer 151 and/or the second light absorbing layer 153 has a high light transmittance for a light, then it has a low light transmittance for this light. Absorption rate.

FIG. 3 is a measurement of the average light transmittance of light emitted in the wavelength range of 550-750 nanometers. As shown in FIG. 3, the average light transmittance and the thickness of the film layer have an approximately inversely proportional relationship. Curve I represents the first light-absorbing layer 151 of P-type doped material, and curve II represents the second light-absorbing layer 153 of CuPc. After the first light-absorbing layer 151 and the second light-absorbing layer 153 are laminated to form the light-absorbing composite layer 150 , the overall average light transmittance may be lower due to the additive effect.

As shown in FIG. 4 , the first light-absorbing layer 151 of P-type doped material has good absorption in the emission wavelength range of about 380-500 nm, and its transmittance is at most 20%. As shown in FIG. 5 , the second light-absorbing layer 153 of CuPc has good absorption in the emission wavelength range of about 550-730 nm, and its transmittance is at most 20%. From the above, it can be seen that the main absorption wavelength ranges of the first light absorbing layer 151 of the P-type doped material and the second light absorbing layer 153 of CuPc are different. In FIG. 4 and FIG. 5, the first wavelength range of the first light-absorbing layer 151 of P-type dopant material can be defined as 380-500 nm, the second wavelength range is 500-780 nm, and the second light-absorbing layer of CuPc The first wavelength range of 153 is 400-550 nm, and the second wavelength range is 550-730 nm. Wherein, the first wavelength range (380-500 nm) of the first light-absorbing layer 151 is different from the second wavelength range (550-730 nm) of the second light-absorbing layer 153 , and the first wavelength range of the first light-absorbing layer 151 The light transmittance in the range (380-500 nm) is smaller than the light transmittance in the second wavelength range (500-780 nm), and the light transmittance in the first wavelength range (400-550 nm) of the second light-absorbing layer 153 The rate is greater than the light transmittance in the second wavelength range (550-730 nm). As shown in Figure 6, when the first light-absorbing layer 151 and the second light-absorbing layer 153 are stacked to form the light-absorbing composite layer 150, the light penetration in the wavelength range of 380-730 nanometers is lower than 20%. The ratio indicates that the light-absorbing composite layer 150 can effectively absorb visible light, and can effectively isolate light leakage between pixel regions.

As shown in FIG. 7, when the thicknesses of the first light-absorbing layer 151 of the P-type doped material and the second light-absorbing layer 153 of CuPc are greater than about 110 nanometers, both the light-absorbing layers 151 and 153 can have a thickness of about Greater than 50% light absorption.

In summary, although the present invention has been disclosed in conjunction with the above preferred embodiments, they are not intended to limit the present invention. Those skilled in the technical field of the present invention can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be defined by the appended claims.

Claims (10)

1. an organic light emitting diode display, has multiple pixel region, and this organic light emitting diode display comprises:

Substrate;

Pixel defining layer, those pixel regions are separated via this pixel defining layer; And

Light absorption composite bed, to be positioned on this substrate and to should pixel defining layer arrange, this light absorption composite bed comprises:

First light absorbing zone, this first light absorbing zone absorbs the light with a first wave length scope; And

Second light absorbing zone, is positioned on this first light absorbing zone, and this second light absorbing zone absorbs the light with a second wave length scope, and wherein, this first wave length scope is different from this second wave length scope.

2. organic light emitting diode display as claimed in claim 1, wherein the light transmittance of this first light absorbing zone under this first wave length scope is 20 ~ 80%, and the light transmittance of this second light absorbing zone under this second wave length scope is 20 ~ 80%.

3. organic light emitting diode display as claimed in claim 1, wherein this first light absorbing zone also absorbs the light with this second wave length scope, and the light transmittance of this first light absorbing zone under this first wave length scope is less than the light transmittance under this second wave length scope.

4. organic light emitting diode display as claimed in claim 3, wherein this second light absorbing zone also absorbs the light with this first wave length scope, and the light transmittance of this second light absorbing zone under this first wave length scope is greater than the light transmittance under this second wave length scope.

5. organic light emitting diode display as claimed in claim 1, wherein the thickness of this first light absorbing zone and the thickness of this second light absorbing zone are respectively between 500 ~ 4000 dusts.

6. organic light emitting diode display as claimed in claim 1, wherein this first light absorbing zone and this second light absorbing zone at least one of them comprises an organic material.

7. organic light emitting diode display as claimed in claim 1, wherein this light absorption composite bed is formed between this substrate and this pixel defining layer.

8. organic light emitting diode display as claimed in claim 1, wherein this light absorption composite bed is positioned in this pixel defining layer.

9. organic light emitting diode display as claimed in claim 1, also comprises:

First electrode layer, to be positioned on this substrate and to arranging by pixel region;

Luminescent layer, to be positioned on this substrate and to cover this pixel defining layer and this first electrode layer; And

The second electrode lay, to be positioned on this substrate and to cover this luminescent layer.

10. organic light emitting diode display as claimed in claim 9, wherein this light absorption composite bed is formed between this luminescent layer and this pixel defining layer.