Organic light-emitting diode display

Abstract

This invention discloses an organic light-emitting diode (OLED) display. The OLED display includes a first stack having a first emitting layer and a second emitting layer. The first emitting layer emits red, green, or blue light. The OLED display also includes a second stack having a second emitting layer and a second emitting layer. The angular spectral distribution of the light emitted from the second stack differs from that of the light emitted from the first stack. Furthermore, the thickness of the second layer differs from that of the first layer, such that light emitted from the first emitting layer resonates at a first degree within the first stack, and light emitted from the second emitting layer resonates at a second degree within the second stack, where the first degree is greater than the second degree.

Description

Technical Field

[0001] This disclosure generally relates to organic light-emitting diode (OLED) displays. Background Technology

[0002] There are many types of OLED displays. Some OLED displays have pixelated OLED display panels, which consist of arrays of individually addressable OLED pixels or subpixels. These pixelated OLED displays are increasingly popular for use in various electronic devices, such as mobile phones, televisions, and similar end-uses. Some OLED displays, called "bottom-emitting" OLED displays, emit light through a semi-transparent substrate on which the OLED display is fabricated. Other OLED displays, called "top-emitting" OLED displays, emit light in the opposite direction, i.e., away from the substrate, and are fabricated on the substrate.

[0003] In various configurations of OLED displays, each of the red, green, and blue subpixels can exhibit color shift depending on the viewing angle, especially when OLED subpixels are optimized for high axial efficiency. Therefore, there is a trade-off between the axial efficiency and color shift of a subpixel. Typically, axial efficiency is sacrificed to achieve lower color shift in OLED displays. However, this trade-off can lead to lower efficiency and uneven color distribution. Summary of the Invention

[0004] Generally, this disclosure relates to organic light-emitting diode (OLED) displays. This disclosure may also relate to OLED displays having enhanced color uniformity and high axial efficiency.

[0005] In one embodiment of this disclosure, the OLED display includes a pixelated OLED display panel comprising a plurality of pixels. Each pixel includes a plurality of subpixels, wherein each subpixel has a plurality of OLED layers. The OLED display includes a first reflective electrode and a second reflective electrode configured to reflect at least a portion of incident light. The OLED display also includes a first semi-reflective electrode and a second semi-reflective electrode disposed opposite to the first and second reflective electrodes, respectively. The first and second semi-reflective electrodes are configured to allow at least a portion of the incident light to pass through them. The OLED display includes a first stack having a first emitting layer disposed between the first reflective electrode and the first semi-reflective electrode. The first emitting layer emits red, green, or blue light. The first stack includes a first layer disposed between the first emitting layer and one of the first reflective electrode or the first semi-reflective electrode. The OLED display includes a second stack spaced apart from the first stack. The second stack has a second emitting layer disposed between the second reflective electrode and the second semi-reflective electrode. The angular spectral distribution of the light emitted from the second stack is different from the angular spectral distribution of the light emitted from the first stack. The second stack includes a second layer disposed between the second emitting layer and one of the second reflective electrode or the second semi-reflective electrode. The thickness of the second layer is different from the thickness of the first layer, such that light emitted from the first emitting layer resonates at a first degree within the first stack and light emitted from the second emitting layer resonates at a second degree within the second stack, the first degree being greater than the second degree.

[0006] In some embodiments, the first layer is a hole transport layer disposed between the first reflective electrode and the first emitter layer. In some embodiments, the second layer is a hole transport layer disposed between the second reflective electrode and the second emitter layer.

[0007] In some embodiments, the first layer is an electron transport layer disposed between the first half-reflective electrode and the first emitting layer. In some embodiments, the second layer is an electron transport layer disposed between the second half-reflective electrode and the second emitting layer.

[0008] In some embodiments, the thickness of the first layer is from about 95 nm to about 114 nm. In some embodiments, the thickness of the second layer is from about 115 nm to about 175 nm.

[0009] In some embodiments, the first emitting layer emits blue light. In some embodiments, the ratio of the thickness of the second layer to the thickness of the first layer is about 1.3 to about 1.6.

[0010] In some embodiments, the first emitting layer emits green light. In some embodiments, the thickness ratio of the second layer to the first layer is about 1.25 to about 1.35.

[0011] In some embodiments, the first emitting layer emits red light. In some embodiments, the ratio of the thickness of the second layer to the thickness of the first layer is about 0.8 to about 1.25.

[0012] In some implementations, the OLED display is a top-emitting type. In some implementations, the OLED display includes drivers for each of the first and second stacks, wherein each driver operates independently. Attached Figure Description

[0013] This disclosure can be more fully understood in conjunction with the following specific embodiments and the accompanying drawings. The drawings are not necessarily drawn to scale. Similar numbers used in the drawings refer to similar parts. However, it should be understood that using numbers to refer to parts in a given drawing is not intended to limit parts labeled with the same numbers in another drawing.

[0014] Figure 1A and Figure 1B This is a schematic cross-sectional view of an organic light-emitting diode (OLED) display;

[0015] Figure 2A and Figure 2B This is a schematic top view of an exemplary OLED display;

[0016] Figures 3A to 3D This is an exemplary graph illustrating the performance of blue light from a tuned blue subpixel;

[0017] Figures 4A to 4D This is an exemplary graph illustrating the performance of combined blue light from tuned and detuned blue subpixels;

[0018] Figure 5 This is a table listing exemplary values ​​for various parameters to illustrate the performance of combined blue light from tuned and detuned blue subpixels;

[0019] Figures 6A to 6D This is an exemplary graph illustrating the performance of green light from a tuned green subpixel;

[0020] Figures 7A to 7D This is an exemplary graph illustrating the performance of combined green light from tuned and detuned green subpixels;

[0021] Figure 8 This is a table listing exemplary values ​​for various parameters to illustrate the performance of combined green light from tuned and detuned green subpixels;

[0022] Figures 9A to 9D This is an exemplary graph illustrating the performance of tuning the red light of the red sub-pixel;

[0023] Figures 10A to 10DThis is an exemplary graph illustrating the performance of combined red light from tuned and detuned red subpixels; and

[0024] Figure 11 This is a table listing exemplary values ​​for various parameters to illustrate the performance of the combined red light from the tuned and detuned red subpixels. Detailed Implementation

[0025] In the following description, reference is made to the accompanying drawings, which form a part thereof, and various embodiments are illustrated therein. It should be understood that other embodiments can be conceived and made without departing from the scope or spirit of this disclosure. Therefore, the following detailed description should not be considered limiting.

[0026] This disclosure relates to an organic light-emitting diode (OLED) display having a first stack and a second stack of layers. The angular spectral distribution of light emitted from the second stack differs from that of light emitted from the first stack. This is achieved by designing the first and second stacks such that light emitted from the first stack resonates while light emitted from the second stack does not. Specifically, the first and second stacks each comprise a first layer and a second layer, wherein the thickness of the second layer differs from the thickness of the first layer to achieve resonance in the first stack and non-resonance in the second stack. The combination of light emitted from the first and second stacks produces lower color shift and higher axial efficiency. OLED displays can be used in various devices, such as mobile phones, televisions, etc.

[0027] As used herein, the term "resonance" refers to the constructive interference of light within a subpixel of an OLED display. Specifically, subpixels can be designed such that, for a specific wavelength of light emitted within the stack, the distance between the electrodes allows the light beams to constructively interfere with each other, thereby producing enhanced light intensity. As used herein, the term "non-resonance" means that the light within the stack does not constructively interfere and the light intensity does not increase.

[0028] Figure 1A A schematic cross-sectional view of an organic light-emitting diode (OLED) display 100a is shown. The OLED display 100a includes a pixelated OLED display panel (not shown) having a plurality of pixels. Pixels are arranged repeatably in columns and rows. Each pixel has a plurality of subpixels. In one embodiment, each pixel includes a red (R) subpixel, a green (G) subpixel, and a blue (B) subpixel. Each subpixel has a plurality of OLED layers.

[0029] refer to Figure 1AThe OLED display 100a includes a first sub-pixel 102a and a second sub-pixel 104a. The first sub-pixel 102a and the second sub-pixel 104a each include a first reflective electrode 106a and a second reflective electrode 108a configured to reflect at least a portion of incident light. For example, the first reflective electrode 106a and / or the second reflective electrode 108a may be configured to reflect at least about 80%, at least about 85%, at least about 90%, at least about 92%, or at least about 95% of the incident light. The OLED display 100a also includes a first semi-reflective electrode 110a disposed opposite to the first reflective electrode 106a and a second semi-reflective electrode 112a disposed opposite to the second reflective electrode 108a. The first semi-reflective electrode 110a and the second semi-reflective electrode 112a are configured to allow at least a portion of the incident light to pass through them. For example, the first semi-reflective electrode 110a and / or the second semi-reflective electrode 112a may be configured to allow at least about 50%, or at least about 60%, or at least about 70% of the incident light to pass through it. In some embodiments, each of the first reflective electrode 106a and the second reflective electrode 108a may be considered an anode, while each of the first semi-reflective electrode 110a and the second semi-reflective electrode 112a may be considered a cathode.

[0030] In some embodiments, the first reflective electrode 106a and the second reflective electrode 108a, as well as the first semi-reflective electrode 110a and the second semi-reflective electrode 112a, are formed using conductive materials such as metals, alloys, metal compounds, conductive metal oxides, conductive dispersions, and conductive polymers, including, for example, gold, silver, nickel, chromium, barium, platinum, palladium, aluminum, calcium, titanium, indium tin oxide (ITO), tin fluoride oxide (FTO), antimony tin oxide (ATO), zinc indium oxide (IZO), poly(3,4-ethylenedioxythiophene) / poly(styrene sulfonic acid), polyaniline, other conductive polymers, alloys thereof, or combinations thereof. The first reflective electrode 106a and the second reflective electrode 108a, as well as the first semi-reflective electrode 110a and the second semi-reflective electrode 112a, can be a single layer of conductive material or can comprise multiple layers of conductive material.

[0031] The substrate material for coating the first reflective electrode 106a and the second reflective electrode 108a can be conductive. In some embodiments, the material used for coating the first reflective electrode 106a and the second reflective electrode 108a is indium tin oxide (ITO). Besides ITO, suitable materials may include indium oxide, tin fluoride oxyfluoride (FTO), zinc oxide, zinc indium oxide (IZO), vanadium oxide, zinc tin oxide, gold, platinum, palladium, aluminum, silver, other high work function metals, and combinations thereof. In one embodiment, the first reflective electrode 106a and the second reflective electrode 108a have an optically thick aluminum (Al) layer coated with a thin layer of indium tin oxide (ITO). The first reflective electrode 106a and the second reflective electrode 108a may have a thickness of approximately 100 nanometers (nm). However, the thickness of the first reflective electrode 106a and / or the second reflective electrode 108a may vary depending on application requirements.

[0032] The first semi-reflective electrode 110a and the second semi-reflective electrode 112a can be formed using low work function metals such as aluminum, barium, calcium, samarium, magnesium, silver, magnesium / silver alloys, lithium, ytterbium, and calcium / magnesium alloys. In one embodiment, the first semi-reflective electrode 110a and the second semi-reflective electrode 112a can be made of magnesium (Mg) and silver (Ag). For example, the composition of the first semi-reflective electrode 110a and the second semi-reflective electrode 112a can be about 90 wt% magnesium and about 10 wt% silver. The first semi-reflective electrode 110a and the second semi-reflective electrode 112a can have a thickness of about 10 nm. However, the thickness of the first semi-reflective electrode 110a and / or the second semi-reflective electrode 112a can vary according to application requirements.

[0033] The first sub-pixel 102a and the second sub-pixel 104a each include a first stack 114a and a second stack 116a, respectively. The second stack 116a is spaced apart from the first stack 114a. The first stack 114a and the second stack 116a have one or more layers. The first stack 114a includes a first emitting layer 118a disposed between the first reflective electrode 106a and the first half-reflective electrode 110a. The second stack 116a includes a second emitting layer 120a disposed between the second reflective electrode 108a and the second half-reflective electrode 112a. The first emitting layer 118a may include one or more organic layers that are modulated to emit light of a desired wavelength in response to a voltage applied between the first reflective electrode 106a and the first half-reflective electrode 110a.

[0034] In the illustrated embodiment, OLED display 100a is a top-emitting OLED display, wherein the first reflective electrode 106a is disposed below the first emitting layer 118a and extracts light from the top via the first semi-reflective electrode 110a. In alternative embodiments, OLED display 100a may be arranged in other configurations such as bottom-emitting or dual-emitting. In other words, the embodiments of this disclosure are not limited to the emission type of OLED display 100a.

[0035] The first emitting layer 118a and the second emitting layer 120a may include a light-emitting material, which is an electroluminescent material that emits light upon electrical activation. In one embodiment, the first emitting layer 118a and the second emitting layer 120a are configured to emit red, green, or blue light. Red, green, and blue light typically have wavelengths ranging from about 600 nm to about 700 nm, about 500 nm to about 560 nm, and about 430 nm to about 490 nm, respectively. In other embodiments, the first emitting layer 118a and the second emitting layer 120a may be configured to emit light of other colors, such as, but not limited to, cyan, magenta, yellow, and orange. In one embodiment, the first emitting layer 118a and the second emitting layer 120a may have a thickness of about 20 nm.

[0036] The first emitting layer 118a and the second emitting layer 120a may comprise one or more light-emitting polymers (LEPs) or other light-emitting materials, such as small molecule (SM) light-emitting compounds. The LEP material may be a conjugated polymer or oligomer with sufficient film-forming properties for solution processing. As used herein, “conjugated polymer or oligomer” refers to a polymer or oligomer having an unlocalized π-electron system along the polymer backbone. Such polymers or oligomers are semiconductive and can support positive and negative charge carriers along the polymeric or oligomeric chains. Exemplary LEP materials include poly(polyphenylacetylene), poly(p-phenylene), polyfluorene, and copolymers or blends thereof. Suitable LEPs may also be doped with small molecule light-emitting compounds, dispersed with fluorescent dyes or phosphorescent dyes or photoluminescent materials, mixed with active or inactive materials, dispersed with active or inactive materials, etc.

[0037] SM materials are typically non-polymeric, organic, or organometallic molecular materials that can be used in OLED displays and devices as light-emitting materials, charge-transporting materials, light-emitting layers (e.g., for controlling emission color), or dopants in charge-transporting layers. Exemplary SM materials include N,N'-bis(3-methylphenyl)-N,N'-diphenylbenzidine (TPD) and metal chelates such as tris(8-hydroxyquinoline)aluminum (Alq3) and biphenyloxybis(8-hydroxyquinoline)aluminum (BAlq).

[0038] In one embodiment, a first stack 114a is disposed between a first reflective electrode 106a and a first half-reflective electrode 110a. The first stack 114a includes a first layer 122a disposed between a first emitter layer 118a and a first reflective electrode 106a. A second stack 116a is disposed between a second reflective electrode 108a and a second half-reflective electrode 112a. The second stack 116a includes a second layer 124a disposed between a second emitter layer 120a and a second reflective electrode 108a. The first layer 122a and the second layer 124a can be hole transport layers, hole injection layers, electron blocking layers, buffer layers, or combinations thereof. The first emitter layer 118a and the second emitter layer 120a can be electron transport layers, electron injection layers, hole blocking layers, emitter layers, buffer layers, or combinations thereof.

[0039] In one embodiment, the first layer 122a is a hole transport layer disposed between the first reflective electrode 106a and the first emitter layer 118a. Within the first stack 114a, the hole transport layer facilitates the injection of holes from the first reflective electrode 106a and their migration toward the recombination region within the first emitter layer 118a. The hole transport layer also serves to block the transport of electrons to the first reflective electrode 106a. Furthermore, the second layer 124a may be a hole transport layer disposed between the second reflective electrode 108a and the second emitter layer 120a. The hole transport layer may include, for example, diamine derivatives (such as N,N'-di(3-methylphenyl)-N,N'-di(phenyl)benzidine (TPD), N,N'-di(2-naphthyl)-N,N'-di(phenyl)benzidine (β-NPB), N,N'-di(1-naphthyl)-N,N'-di(phenyl)benzidine (NPB) or the like); or triaromatic amine derivatives (such as 4,4′,4″-tris(N,N-diphenylamine)triphenylamine (TDATA), 4,4′,4″-tris(N-3-methylphenyl-N-phenyl)triphenylamine (MTDATA), 4,4′,4″-tris(N-phenazinyl)triphenylamine (TPOTA), 1,3,5-tris(4-diphenylaminophenyl)benzene (TDAPB) or the like).

[0040] Figure 1B A schematic cross-sectional view of an OLED display 100b according to another embodiment of this disclosure is shown. OLED display 100b has components similar to those of OLED display 100a. Figure 1BAs shown, the OLED display 100b includes a first sub-pixel 102b and a second sub-pixel 104b. The first sub-pixel 102b and the second sub-pixel 104b each include a first reflective electrode 106b and a second reflective electrode 108b configured to reflect at least a portion of incident light. The OLED display 100b also includes a first semi-reflective electrode 110b disposed opposite to the first reflective electrode 106b and a second semi-reflective electrode 112b disposed opposite to the second reflective electrode 108b. The first semi-reflective electrode 110b and the second semi-reflective electrode 112b are configured to allow at least a portion of the incident light to pass through them.

[0041] The first sub-pixel 102b includes a first stack 114b disposed between the first reflective electrode 106b and the first half-reflective electrode 110b. The first stack 114b includes a first layer 118b disposed between the first emitter layer 122b and the first half-reflective electrode 110b. The second sub-pixel 104b includes a second stack 116b disposed between the second reflective electrode 108b and the second half-reflective electrode 112b. The second stack 116b includes a second layer 120b disposed between the second emitter layer 124b and the second half-reflective electrode 112b. The first layer 118b and the second layer 120b can be an electron transport layer, an electron injection layer, a hole blocking layer, a buffer layer, or a combination thereof. The first emitter layer 122b and the second emitter layer 124b can be a hole transport layer, a hole injection layer, an electron blocking layer, an emitter layer, a buffer layer, or a combination thereof.

[0042] Within the first stack 114b, the electron transport layer facilitates the injection of electrons from the first half-reflective electrode 110b and their migration toward the recombination region within the first emitter layer 122b. The electron transport layer also serves to block the transport of holes to the first half-reflective electrode 110b. Furthermore, the second layer 120b may be an electron transport layer disposed between the second half-reflective electrode 112b and the second emitter layer 124b.

[0043] Electron transport layers can be formed using organometallic compounds such as tris(8-hydroxyquinoline)aluminum (Alq3) and biphenyloxybis(8-hydroxyquinoline)aluminum (BAlq)). Other examples of useful electron transport materials in electron transport layers include 1,3-bis[5-(4-(1,1-dimethylethyl)phenyl)-1,3,4-oxadiazon-2-yl]benzene; 2-(biphenyl-4-yl)-5-(4-(1,1-dimethylethyl)phenyl)-1,3,4-oxadiazole; 9,10-bis(2-naphthyl)anthracene (ADN); 2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole; or 3-(4-biphenyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (TAZ).

[0044] In sub-pixel 102a, light emitted from the first emitting layer 118a forms a microcavity, while simultaneously reciprocating between the first reflecting electrode 106a and the first semi-reflecting electrode 110a. Similar microcavities are also formed in sub-pixels 104a, 102b, and 104b. The first stack 114a can be designed to exhibit a resonant phenomenon, in which the light beams can constructively interfere with each other. Therefore, the light intensity extracted from the first stack 114a can be enhanced. In various embodiments of this disclosure, sub-pixel 102a may be referred to as tuned sub-pixel 102a. The thickness of the first layer 122a can be designed such that light emitted from the first emitting layer 118a resonates within the first stack 114a. In some embodiments, the thickness of the first layer 122a is about 95 nm to about 114 nm.

[0045] In sub-pixel 104a, the second stack 116a can be designed such that the light beams do not constructively interfere with each other and do not resonate. Specifically, the thickness of the second layer 124a can be designed such that light emitted from the second emitting layer 120a does not resonate within the second stack 116a. In various embodiments of this disclosure, sub-pixel 104a may be referred to as detuned sub-pixel 104a. The angular spectral distribution of light emitted from the second stack 116a differs from that of light emitted from the first stack 114a. For example, the light emitted from the second stack 116a may have a different brightness (or luminance) versus viewing angle or wavelength versus viewing angle distribution compared to the brightness (or luminance) versus viewing angle or wavelength versus viewing angle distribution of light emitted from the first stack 114a.

[0046] In some embodiments, light emitted from the first emitting layer 118a resonates at a first degree within the first stack 114a, while light emitted from the second emitting layer 120a resonates at a second degree within the second stack 116a. In some embodiments, the first degree is greater than the second degree.

[0047] In some embodiments, light emitted from the first emitting layer 118b resonates at a first degree within the first stack 114b, while light emitted from the second emitting layer 120b resonates at a second degree within the second stack 116b. In some embodiments, the first degree is greater than the second degree.

[0048] refer to Figure 1A The thickness of the second layer 124a differs from the thickness of the first layer 122a. In one embodiment, the thickness of the second layer 124a is approximately 115 nm to approximately 175 nm, and the thickness of the first layer 122a is approximately 95 nm to approximately 114 nm. Similarly, in the illustrated... Figure 1B In the implementation scheme, the thickness of the second layer 120b is different from the thickness of the first layer 118b.

[0049] The thicknesses of the first layer 122a and the second layer 124a can each depend on the color of the light emitted by the first emitting layer 118a and the second emitting layer 120a. For example, when the first emitting layer 118a and the second emitting layer 120a emit blue light, the ratio of the thickness of the second layer 124a to the thickness of the first layer 122a is approximately 1.3 to approximately 1.6. Similarly, when the first emitting layer 118a and the second emitting layer 120a emit green light, the ratio of the thickness of the second layer 124a to the thickness of the first layer 122a is approximately 1.25 to approximately 1.35. Furthermore, when the first emitting layer 118a and the second emitting layer 120a emit red light, the ratio of the thickness of the second layer 124a to the thickness of the first layer 122a is approximately 0.8 to approximately 1.25.

[0050] The combination of detuned sub-pixel 104a and tuned sub-pixel 102a produces improved color uniformity and lower color shift. For example, when the first stack 114a emits blue light, the light from the detuned sub-pixel 104a mixes with the blue light from the tuned sub-pixel 102a, and the resulting blue light has better axial efficiency and lower color shift compared to light from the tuned sub-pixel 102a alone. Therefore, the color performance of the OLED display 100a is improved.

[0051] In some embodiments, the OLED display 100a includes a driver for each of the sub-pixels 102a and 104a. The driver can be configured to supply the current required to drive the sub-pixels. In one embodiment, each driver operates independently. The current supplied to the tuned sub-pixel 102a and the current supplied to the detuned sub-pixel 104a can be controlled independently of each other to achieve desired color shift and axial efficiency. Therefore, the detuned sub-pixel 104a provides additional degrees of freedom for controlling the OLED display 100a compared to a standard OLED display.

[0052] Figure 2A and Figure 2B The illustration shows a top view of an OLED display 200. The OLED display 200 includes a red (R) subpixel 202, a green (G) subpixel 204, a blue (B) subpixel 206, and a detuned subpixel 208. In the illustrated embodiment, the detuned subpixel 208 is associated with the blue subpixel 206. The blue subpixel 206 is designed to exhibit resonance (tuning), while the detuned subpixel 208 is designed to not exhibit resonance (detuning). Specifically, the thickness of each layer of subpixels 206 and 208 can be selected such that the blue subpixel 206 is tuned and the detuned subpixel 208 is detuned.

[0053] refer to Figure 2AWhen viewed from above, the blue subpixel 206 and the detuned subpixel 208 have similar cross-sectional dimensions. However, in other embodiments, when viewed from above, the detuned subpixel 208′ may have a smaller cross-sectional dimension compared to the blue subpixel 206, such as... Figure 2B As shown. Figure 2A and Figure 2B The configuration shown can be referred to as an RGBB′ ​​configuration with two blue sub-pixels (tuning (B) and detuning (B′)).

[0054] In various embodiments, the detuned subpixel 208 may be associated with either the red subpixel 202 or the green subpixel 204. For example, the OLED display 200 may have an RR′GB or RGG′B configuration. Furthermore, the OLED display 200 may include multiple detuned subpixels 208. For example, the OLED display 200 may include two detuned subpixels, resulting in an RR′GG′B, RR′GBB′, or RGG′BB′ configuration. In one embodiment, the OLED display 200 includes three detuned subpixels 208, one each for the red subpixel 202, the green subpixel 204, and the blue subpixel 206, resulting in an RR′GG′BB′ configuration. The aforementioned configurations may be needed to simultaneously optimize the performance of multiple colors in the OLED display 200. The use of red, green, and blue light in various embodiments of this disclosure is exemplary, and it should be understood that other colors of light, such as, but not limited to, cyan, magenta, yellow, and orange, may also be used.

[0055] Figures 3A to 3D This is an exemplary graph illustrating the performance of blue light from a tuned blue subpixel. Figure 3A This illustrates the relationship between the blue color shift of the tuned blue subpixel and the thickness of the hole transport layer (HTL) layer. Figure 3B This shows the relationship between the blue axial efficiency of the tuned blue subpixel and the thickness of the HTL layer. Figure 3A and Figure 3B The results show that the blue axial efficiency increases with the thickness of the tuned HTL, and the blue color shift also increases with the thickness of the tuned HTL. Therefore, it is difficult to achieve high axial efficiency without compromising the color shift. Figure 3C and Figure 3D This shows the relationship between the chromaticity coordinates (CIEx, CIEy) of the tuned blue subpixel and the thickness of the HTL layer.

[0056] Figures 4A to 4D This is an exemplary graph illustrating the performance of combined blue light from tuned and detuned blue subpixels. In these examples, the thickness of the HTL layer of the tuned subpixel is approximately 103 nm. The detuning current is defined as the percentage ratio of the current applied to the detuned subpixel to the total current applied to both the tuned and detuned subpixels. Figure 4AThe relationship between the blue color shift of the detuned blue subpixel for different values ​​of detuning current and the thickness of the HTL layer is shown. Figure 4B The relationship between the total blue axial efficiency of the detuned blue subpixel and the thickness of the HTL layer is shown for different values ​​of detuned current. Figure 4A and Figure 4B The results show that for a detuned HTL thickness of approximately 140 nm and a detuned current of 30%, a total blue axial efficiency of approximately 7.8 and a total blue color shift of approximately 0.012 can be achieved. Therefore, a combination of tuned and detuned blue subpixels can be used to achieve high axial efficiency and low color shift. Figure 4C and Figure 4D The relationship between the chromaticity coordinates (CIEx, CIEy) of the detuned blue subpixel for different values ​​of detuned current and the thickness of the HTL layer is shown.

[0057] Figure 5 This table lists exemplary values ​​for various parameters to illustrate the performance of the combined blue light from the tuned and detuned blue subpixels. For example, when the tuned HTL thickness is approximately 104 nm, the detuned HTL thickness is approximately 146 nm, and the detuning current is approximately 10%, the combination of the tuned and detuned blue subpixels produces a blue color shift of approximately 0.06 and a total axial efficiency of approximately 5.2. Therefore, a low blue color shift can be achieved without significantly degrading the axial efficiency.

[0058] Figures 6A to 6D This is an exemplary graph illustrating the performance of green light from a tuned green subpixel. Figure 6A This illustrates the relationship between the green color shift of the tuned green subpixel and the thickness of the HTL layer. Figure 6B This illustrates the relationship between the green axial efficiency of tuned green subpixels and the thickness of the HTL layer. Figure 6C and Figure 6D This shows the relationship between the chromaticity coordinates (CIEx, CIEy) of the tuned green subpixel and the thickness of the HTL layer.

[0059] Figures 7A to 7D This is an exemplary graph illustrating the performance of combined green light from tuned and detuned green subpixels. In these examples, the thickness of the HTL layer for the tuned green subpixel is approximately 143 nm. Figure 7A The relationship between the green color shift of the detuned green subpixel for different values ​​of detuning current and the thickness of the HTL layer is shown. Figure 7B The relationship between the total green axial efficiency of the detuned green subpixel and the thickness of the HTL layer is shown for different values ​​of detuned current. Figure 7A and Figure 7BThe results show that for a detuned HTL thickness of approximately 194 nm and a detuning current of 5%, a total green axial efficiency of approximately 114.3 and a total green color shift of approximately 0.021 can be achieved. Therefore, a combination of tuned and detuned green subpixels can be used to achieve high axial efficiency and low color shift. Figure 7C and Figure 7D The relationship between the chromaticity coordinates (CIEx, CIEy) of the detuned green subpixels for different values ​​of detuned current and the thickness of the HTL layer is shown.

[0060] Figure 8 This table lists exemplary values ​​for various parameters to illustrate the performance of combined tuned and detuned green subpixels in green light. For example, when the tuned HTL thickness is approximately 144 nm, the detuned HTL thickness is approximately 194 nm, and the detuning current is approximately 10%, the combination of tuned and detuned green subpixels produces a green color shift of approximately 0.017 and a total axial efficiency of approximately 109.7. Therefore, a low green color shift can be achieved without significantly degrading the axial efficiency.

[0061] Figures 9A to 9D This is an exemplary graph illustrating the performance of tuning the red light of the red sub-pixel. Figure 9A This shows the relationship between the red color shift of the tuned red subpixel and the thickness of the HTL layer. Figure 9B This shows the relationship between the red axial efficiency of the tuned red subpixel and the thickness of the HTL layer. Figure 9C and Figure 9D This shows the relationship between the chromaticity coordinates (CIEx, CIEy) of the tuned red subpixel and the thickness of the HTL layer.

[0062] Figures 10A to 10D This is an exemplary graph illustrating the performance of combined red light from a tuned red subpixel and a detuned red subpixel. In these examples, the thickness of the HTL layer for the tuned red subpixel is approximately 198 nm. Figure 10A The relationship between the red color shift of the detuned red subpixel for different values ​​of detuned current and the thickness of the HTL layer is shown. Figure 10B The relationship between the total red axial efficiency of the detuned red subpixel and the thickness of the HTL layer is shown for different values ​​of detuned current. Figure 10A and Figure 10B The results show that for a detuned HTL thickness of approximately 230 nm and a detuning current of 1%, a total red axial efficiency of approximately 32 and a total red color shift of approximately 0.083 can be obtained. Therefore, it is possible to achieve high axial efficiency and low color shift using a combination of tuned and detuned red subpixels. Figure 10C and Figure 10DThe relationship between the chromaticity coordinates (CIEx, CIEy) of the detuned red subpixel for different values ​​of detuning current and the thickness of the HTL layer is shown.

[0063] Figure 11 This table lists exemplary values ​​for various parameters to illustrate the performance of the combined red light from the tuned and detuned red subpixels; for example, when the tuned HTL thickness is approximately 190 nm, the detuned HTL thickness is approximately 230 nm, and the detuning current is approximately 20%, the combination of the tuned and detuned red subpixels produces a red color shift of approximately 0.056 and a total axial efficiency of approximately 26.7. Therefore, a low red color shift can be achieved without significantly degrading the axial efficiency.

[0064] Unless otherwise stated, all figures used in the specification and claims to indicate feature dimensions, quantities, and physical properties should be understood to be modified by the term "about". Therefore, unless stated to the contrary, the numerical parameters listed in the foregoing specification and appended claims are approximations and can vary according to the desired properties sought by those skilled in the art using the teachings disclosed herein.

[0065] While specific embodiments have been illustrated and described herein, those skilled in the art will recognize that various alternative and / or equivalent embodiments may be used in place of the illustrated and described embodiments without departing from the scope of this disclosure. This application is intended to cover any modifications or variations of the specific embodiments discussed herein. Therefore, this disclosure is intended to be limited only by the claims and their equivalents.

Claims

1. An organic light-emitting diode (OLED) display, the OLED display comprising: A pixelated OLED display panel, the pixelated OLED display panel comprising a plurality of pixels, each pixel comprising a plurality of sub-pixels, each sub-pixel comprising a plurality of OLED layers; a first reflective electrode configured to reflect at least a portion of incident light; A first half-reflective electrode is disposed opposite to a first reflective electrode, and the first half-reflective electrode is configured to allow at least a portion of the incident light to pass through it; A second reflective electrode, configured to reflect at least a portion of the incident light; A second half-reflective electrode is disposed opposite to a second reflective electrode, and the second half-reflective electrode is configured to allow at least a portion of the incident light to pass through it; A first stack, the first stack comprising: A first emitting layer is disposed between the first reflective electrode and the first semi-reflective electrode, wherein the first emitting layer emits red light, green light, or blue light; and A first layer, wherein the first layer is disposed between the first emitting layer and one of the first reflective electrode or the first semi-reflective electrode; and A second stack, spaced apart from the first stack, includes: A second emitting layer is disposed between the second reflective electrode and the second semi-reflective electrode, wherein the light emitted from the second stack has the same color as the light emitted from the first emitting layer, and the angular spectral distribution of the light emitted from the second stack is different from that of the light emitted from the first stack; and A second layer is disposed between the second emitting layer and one of the second reflective electrode or the second half-reflective electrode, wherein the thickness of the second layer is different from the thickness of the first layer, such that light emitted from the first emitting layer resonates within the first stack, while light emitted from the second emitting layer does not resonate within the second stack. The first stack and the second stack are spaced apart. The first stack includes a first sub-pixel among a plurality of sub-pixels of a first pixel in the plurality of pixels. The second stack includes a second sub-pixel among the plurality of sub-pixels of the first pixel.

2. The OLED display according to claim 1, wherein the first layer is a hole transport layer disposed between the first reflective electrode and the first emitting layer.

3. The OLED display according to claim 1, wherein the second layer is a hole transport layer disposed between the second reflective electrode and the second emitting layer.

4. The OLED display according to claim 1, wherein the thickness of the second layer is from about 115 nm to about 175 nm.

5. The OLED display according to claim 1, wherein the thickness of the first layer is about 95 nm to about 114 nm.

6. The OLED display of claim 1, wherein the first emitting layer emits blue light.

7. The OLED display of claim 6, wherein the ratio of the thickness of the second layer to the thickness of the first layer is about 1.3 to about 1.

6.

8. The OLED display of claim 1, wherein the first emitting layer emits green light.

9. The OLED display of claim 8, wherein the ratio of the thickness of the second layer to the thickness of the first layer is about 1.25 to about 1.

35.

10. The OLED display of claim 1, wherein the first emitting layer emits red light.

11. The OLED display of claim 10, wherein the ratio of the thickness of the second layer to the thickness of the first layer is from about 0.8 to about 1.

25.

12. The OLED display according to claim 1, wherein the second layer is an electron transport layer disposed between the second semi-reflective electrode and the second emitting layer.

13. The OLED display according to claim 1, wherein the first layer is an electron transport layer disposed between the first semi-reflective electrode and the first emitting layer.

14. The OLED display of claim 1, wherein the OLED display is a top-emitting type.

15. The OLED display of claim 1, further comprising a driver for each of the first stack and the second stack, wherein each driver operates independently.

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