CN113594386B

CN113594386B - Display panel and display device

Info

Publication number: CN113594386B
Application number: CN202110859924.7A
Authority: CN
Inventors: 黄冠达; 陈小川; 李育豪; 王辉; 段东东; 申晓斌; 童慧; 杨盛际; 卢鹏程
Original assignee: BOE Technology Group Co Ltd; Yunnan Chuangshijie Optoelectronics Technology Co Ltd
Current assignee: BOE Technology Group Co Ltd; Yunnan Chuangshijie Optoelectronics Technology Co Ltd
Priority date: 2021-07-28
Filing date: 2021-07-28
Publication date: 2022-09-23
Anticipated expiration: 2041-07-28
Also published as: CN113594386A

Abstract

The embodiment of the disclosure provides a display panel and a display device, relates to the technical field of display, and aims to solve the problem that in the display device, the color cast of a display picture is displayed under a side view angle. The display panel comprises a plurality of sub-pixels, wherein the actual light-emitting area of one sub-pixel comprises a central light-emitting area and an edge light-emitting area, and a micro-cavity with uniform cavity length is formed in the central light-emitting area; when the sub-pixel is applied with the corresponding maximum gray scale voltage, the area ratio of the central light-emitting area to the edge light-emitting area is the area ratio of the sub-pixel. The at least one sub-pixel includes a first sub-pixel and a second sub-pixel, a spectral peak wavelength of light emitted from the center emission region of the first sub-pixel is substantially the same as a spectral peak wavelength of light emitted from the edge emission region, and a spectral peak wavelength of light emitted from the center emission region of the second sub-pixel is different from the spectral peak wavelength of light emitted from the edge emission region. And the area ratio of the second sub-pixel is less than or equal to 15.

Description

Display panel and display device

Technical Field

The invention relates to the technical field of display, in particular to a display panel and a display device.

Background

The micro display technology of silicon-based OLED (Organic Light Emitting Diode) is the combination of OLED photoelectronic technology and silicon-based integrated circuit microelectronic technology, and is mainly applied in the micro display field. In the current silicon-based OLED display device, a phenomenon of displaying a color cast of a picture at a side viewing angle exists.

Disclosure of Invention

Embodiments of the present invention provide a display panel and a display device, so as to solve the problem of color cast of a display screen in a side view of the display device.

In order to achieve the above purpose, the embodiment of the invention adopts the following technical scheme:

in a first aspect, there is provided a display panel including a plurality of sub-pixels, an actual light-emitting area of a sub-pixel including a central light-emitting area and an edge light-emitting area, the sub-pixels forming a microcavity having a uniform cavity length in the central light-emitting area, the edge light-emitting area being an area of the actual light-emitting area other than the central light-emitting area; the actual light-emitting area of the sub-pixel is an area which can emit light when the sub-pixel is applied with the maximum gray scale voltage corresponding to the sub-pixel, and the ratio of the area of the central light-emitting area of the sub-pixel to the area of the edge light-emitting area of the sub-pixel is the area ratio of the sub-pixel. In the display panel, the plurality of sub-pixels include a first sub-pixel configured to emit a first color light and a second sub-pixel configured to emit a second color light, a spectral peak wavelength of the first color light emitted from a central emission region of the first sub-pixel is substantially the same as a spectral peak wavelength of the first color light emitted from an edge emission region of the first sub-pixel, and a spectral peak wavelength of the second color light emitted from a central emission region of the second sub-pixel is different from a spectral peak wavelength of the second color light emitted from an edge emission region of the second sub-pixel. And the area ratio of the second sub-pixel is less than or equal to 15.

In some embodiments, the area ratio of the second sub-pixel is less than or equal to 10.

In some embodiments, the area ratio of the first sub-pixel is greater than the area ratio of the second sub-pixel.

In some embodiments, the area of the central light emitting area of the first sub-pixel is larger than the area of the central light emitting area of the second sub-pixel.

In some embodiments, the at least one sub-pixel further comprises a third sub-pixel configured to emit light of a third color. The spectral peak wavelength of the third color light emitted from the central emitting region of the third sub-pixel is substantially the same as the spectral peak wavelength of the third color light emitted from the edge emitting region of the third sub-pixel, and the area ratio of the third sub-pixel is larger than that of the second sub-pixel.

In some embodiments, the second sub-pixel emits the second color light as red light.

In some embodiments, a subpixel includes a light emitting device configured to emit white light and a color filter pattern.

In some embodiments, a light emitting device includes first and second electrodes disposed opposite to each other, and a light emitting function layer disposed between the first and second electrodes. In one sub-pixel, the area of the edge light-emitting area is the product of the perimeter of the central light-emitting area and a width parameter, and the width parameter is obtained according to the thickness of the light-emitting functional layer in the sub-pixel and the maximum gray scale voltage corresponding to the sub-pixel.

In some embodiments, the thickness of the light emitting functional layer is greater than or equal to 300 nm.

In some embodiments, the display panel further comprises a driving backplane configured to carry the light emitting devices. The driving back plate comprises a silicon substrate and at least one pixel driving circuit arranged on the silicon substrate, wherein one pixel driving circuit is coupled with the light emitting device in one sub-pixel.

In some embodiments, the resolution of the display panel is greater than or equal to 3500 ppi.

In some embodiments, the edges of the central light-emitting area in a sub-pixel are circular, elliptical or polygonal.

In a second aspect, a display device is provided, and the display device includes the display panel provided in any of the above embodiments.

In the display panel, in the actual light emitting region of the first sub-pixel, the center light emitting region includes a microcavity structure, and the spectral peak wavelengths of the first color light emitted by the center light emitting region and the first color light emitted by the edge light emitting region are substantially the same. In this way, under the combined action of the central light-emitting region and the edge light-emitting region, the luminance change tendency of the first color light emitted by the first sub-pixel is steadily decreased as the side viewing angle is increased. In the actual light-emitting area of the second sub-pixel, the central light-emitting area comprises a micro-cavity structure, and the spectral peak wavelengths of the second color light emitted by the central light-emitting area and the second color light emitted by the edge light-emitting area are different, so that under the combined action of the central light-emitting area and the edge light-emitting area, the brightness attenuation trend of the second color light emitted by the second sub-pixel is firstly stably reduced and then improved along with the increase of the side viewing angle. At the stage of increasing the brightness of the second color light emitted by the second sub-pixel, the display frame of the display panel has a color cast phenomenon because the brightness change trend of the second color light emitted by the second sub-pixel is not in accordance with the brightness change trend of the first color light emitted by the first sub-pixel. Also, because in the display panel provided by the embodiment of the present disclosure, the area ratio of the second sub-pixel, that is, the ratio of the area of the central light-emitting area of the second sub-pixel to the area of the edge light-emitting area of the second sub-pixel when the second sub-pixel is applied with the corresponding maximum gray scale voltage is less than or equal to 15, in the actual light-emitting area of the second sub-pixel, the influence of the edge light-emitting area becomes large, and the luminance of the second color light emitted by the second sub-pixel can be stably reduced in a larger viewing angle range. Therefore, in a larger viewing angle range, the brightness attenuation trend of the light emitted by the second sub-pixel is consistent with the brightness attenuation trend of the light emitted by the first sub-pixel, and the color cast phenomenon of a display picture of the display panel under a large viewing angle can be improved.

It can be understood that the display device according to the second aspect includes the display panel, and therefore, the beneficial effects achieved by the display device can refer to the beneficial effects of the display panel, which are not described herein again.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is a partial structural diagram of a display panel according to an embodiment of the disclosure;

FIG. 2A is a cross-sectional view of the display panel of FIG. 1 taken along line SS';

FIG. 2B is a cross-sectional view of the display panel of FIG. 1 taken along line SS';

FIG. 2C is a cross-sectional view of the display panel of FIG. 1 taken along line SS';

fig. 3 is a spectrum diagram of a light emitting device in a display panel emitting white light according to an embodiment of the present disclosure;

fig. 4 is a schematic view illustrating a change rate of the viewing angle brightness of different sub-pixels in the display panel according to the embodiment of the disclosure;

FIG. 5 is a schematic diagram illustrating a relationship between a C/E value and a spectral peak wavelength of a sub-pixel in a display panel according to an embodiment of the present disclosure;

fig. 6 is a schematic diagram illustrating a trend that luminance of a sub-pixel attenuates with an increasing viewing angle under different C/E values when a ratio of an area of a central light-emitting area to an area of an edge light-emitting area of the sub-pixel is different in a display panel provided by an embodiment of the present disclosure;

fig. 7 is a schematic diagram illustrating a relationship between a thickness and a voltage of a light-emitting functional layer of a light-emitting device of a sub-pixel in a display panel and a width parameter of the sub-pixel according to an embodiment of the disclosure;

fig. 8 is a schematic diagram illustrating a relationship between a thickness of a light-emitting functional layer of a light-emitting device of a sub-pixel in a display panel, a C/E value of the sub-pixel, and a resolution of the display panel according to an embodiment of the disclosure;

fig. 9 is a schematic diagram illustrating a relationship between a thickness of a light-emitting functional layer of a light-emitting device of a sub-pixel in a display panel, a C/E value of the sub-pixel, and a resolution of the display panel according to an embodiment of the present disclosure.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without inventive step based on the embodiments of the present invention, are within the scope of protection of the present invention.

In the description of the present invention, it is to be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be construed as limiting the present invention.

Unless the context requires otherwise, throughout the description and the claims, the word "comprise" and its other forms, such as "comprises" and "comprising", will be interpreted as open, inclusive meaning that the word "comprise" and "comprises" will be interpreted as meaning "including, but not limited to", in the singular. In the description of the specification, the terms "one embodiment", "some embodiments", "example", "specific example" or "some examples" and the like are intended to indicate that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present disclosure. The schematic representations of the terms used above are not necessarily referring to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics may be included in any suitable manner in any one or more embodiments or examples.

In the following, the terms "first", "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the embodiments of the present disclosure, "a plurality" means two or more unless otherwise specified.

In describing some embodiments, the expressions "coupled" and "connected," along with their derivatives, may be used. For example, the term "connected" may be used in describing some embodiments to indicate that two or more elements are in direct physical or electrical contact with each other. As another example, some embodiments may be described using the term "coupled" to indicate that two or more elements are in direct physical or electrical contact. However, the terms "coupled" or "communicatively coupled" may also mean that two or more elements are not in direct contact with each other, but yet still co-operate or interact with each other. The embodiments disclosed herein are not necessarily limited to the contents herein.

At least one of "A, B and C" has the same meaning as "A, B or at least one of C," both including the following combination of A, B and C: a alone, B alone, C alone, a combination of a and B, a combination of a and C, a combination of B and C, and a combination of A, B and C.

"A and/or B" includes the following three combinations: a alone, B alone, and a combination of A and B.

"plurality" means at least two.

The use of "adapted to" or "configured to" herein means open and inclusive language that does not exclude devices adapted to or configured to perform additional tasks or steps.

Additionally, the use of "based on" is meant to be open and inclusive in that a process, step, calculation, or other action that is "based on" one or more stated conditions or values may, in practice, be based on additional conditions or exceed the stated values.

As used herein, "about," "approximately," or "approximately" includes the stated values as well as average values that are within an acceptable range of deviation for the particular value, as determined by one of ordinary skill in the art in view of the measurement in question and the error associated with measurement of the particular quantity (i.e., the limitations of the measurement system).

Example embodiments are described herein with reference to cross-sectional and/or plan views as idealized example figures. In the drawings, the thickness of layers and regions are exaggerated for clarity. Variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, the exemplary embodiments should not be construed as limited to the shapes of regions illustrated herein but are to include deviations in shapes that result, for example, from manufacturing. For example, an etched region shown as a rectangle will typically have curved features. Thus, the regions illustrated in the figures are schematic in nature and their shapes are not intended to illustrate the actual shape of a region of a device and are not intended to limit the scope of the exemplary embodiments.

Embodiments of the present disclosure provide a display device. The display device is a product having an image display function, and may be, for example: a display, a television, a billboard, a Digital photo frame, a laser printer with a display function, a telephone, a mobile phone, a tablet computer, a game machine, a Personal Digital Assistant (PDA), a Digital camera, a camcorder, a viewfinder, a navigator, a vehicle, a large-area wall, a home appliance, an information inquiry apparatus (e.g., a business inquiry apparatus, a monitor, etc. in the departments of e-government, bank, hospital, electric power, etc.).

The display device may include a display panel, and the display device may further include a driving circuit coupled to the display panel, the driving circuit being configured to provide an electrical signal to the display panel. Illustratively, the driving circuit may include: a Source Driver IC (Source Driver IC) configured to supply a data driving signal (also referred to as a data signal) to the display panel. The driving circuit may further include a Timing Controller (TCON) or the like coupled to the source driver.

Illustratively, the display panel may be an OLED (Organic Light Emitting Diode) display panel, a QLED (Quantum Dot Light Emitting Diode) display panel, a micro LED (including a miniLED or a micro LED, where the LED is a Light Emitting Diode) display panel, or the like. The OLED display panel will be described as an example.

The display panel may include at least one pixel (e.g., a plurality of pixels). A pixel (e.g., each pixel) may include a plurality of sub-pixels having different emission colors, that is, the display panel may include a plurality of sub-pixels. Fig. 1 is a partial structural view of a display panel, showing the structure of a pixel. Referring to fig. 1, the plurality of subpixels may include a first subpixel 10 and a second subpixel 20. The first sub-pixel 10 emits the first color light and the second sub-pixel 20 emits the second color light. By controlling the intensity of the first color light and the intensity of the second color light, the pixel can be made to display patches of different colors. In some embodiments, the plurality of sub-pixels in a pixel further includes a third sub-pixel 30, the third sub-pixel 30 emitting a third color light. At this time, by controlling the intensity of the first color light, the intensity of the second color light, and the intensity of the third color light, the pixel can be made to display patches of different colors. Illustratively, the display panel may include three primary color sub-pixels, for example, the display panel may include a red sub-pixel emitting red light, a green sub-pixel emitting green light, and a blue sub-pixel emitting blue light. Accordingly, the first sub-pixel may be a blue sub-pixel, the second sub-pixel may be a red sub-pixel, and the third sub-pixel may be a green sub-pixel. Alternatively, the first sub-pixel may be a green sub-pixel; the second sub-pixel may be a red sub-pixel; the third sub-pixel may be a blue sub-pixel.

In some embodiments, referring to fig. 2A, fig. 2A is a cross-sectional view of the display panel of fig. 1 along SS'. A subpixel may include a light emitting device 110 configured to emit white light and a color film pattern 120. Illustratively, the first subpixel is a blue subpixel, and the first subpixel may include a white OLED (i.e., an OLED for emitting white light) and a blue color film pattern; the second sub-pixel is a red sub-pixel, and the second sub-pixel can comprise a white light OLED and a red color film pattern; the third sub-pixel is a green sub-pixel, and the third sub-pixel may include a white OLED and a green color film pattern.

Among them, the light emitting device 110 emitting white light may be a white OLED. Specifically, the spectrum of white light emitted by the white OLED may be as shown in fig. 3, and referring to fig. 3, the white light may include three wavelength bands: the blue wavelength band, for example, includes 450nm to 470 nm; the green wavelength band, for example, including 520nm to 550 nm; and a red light band, including 610nm to 700nm, for example. In addition, the white light spectrum includes three intrinsic emission peaks, wherein the intrinsic emission peaks refer to emission peaks in the spectrum of light emitted by the material itself, and can be used for characterizing the light emission characteristics of the material itself. The three intrinsic emission peaks are, for example, intrinsic emission peaks located in the blue light band, and the peak wavelength thereof may be between 450nm and 470nm, for example, 460 nm; an intrinsic emission peak in the green wavelength band, the peak wavelength of which may be between 520nm and 550nm, for example 530 nm; the intrinsic emission peak in the red band may have a peak wavelength between 610nm and 700nm, for example 620 nm.

On this basis, with continued reference to fig. 1 and fig. 2A, the color film pattern 120 may enable the light emitted by the light emitting device 110 to pass through the color film pattern 120 and then emit light of a corresponding color. For example, for a blue sub-pixel, the blue color film pattern included therein may allow blue light to exit and block part or all of light in other wavelength bands, for example, the blue color film pattern allows blue light with a wavelength in a range of 450nm to 470nm to exit; for the green sub-pixel, the green color film pattern included therein may allow green light to exit and block part or all of light in other wavelength bands, for example, the green color film pattern allows green light with a wavelength of 520nm to 550nm to exit; for the red sub-pixel, the red color film pattern included therein may allow red light to exit and block part or all of light in other wavelength bands, for example, the red color film pattern may allow red light with a wavelength of 610nm to 700nm to exit.

In addition, a microcavity structure may also be formed in the light emitting device 110. In some embodiments, the light emitting device emitting white light in the sub-pixel may be a top emission type OLED in which a microcavity structure may be formed. In some possible implementations, the display panel 1 further includes a driving backplane 130, the driving backplane 130 is configured to carry the light emitting device 110, and the driving backplane 130 may include a silicon substrate 131 and at least one pixel driving circuit 132 disposed on the silicon substrate 131. A pixel driving circuit 132 may be coupled to the light emitting device 110 in a sub-pixel to provide an electrical signal to the light emitting device 110. Specifically, one pixel driving circuit 132 may include a plurality of transistors and at least one (e.g., one) capacitor, for example, the pixel driving circuit 132 may have a structure of "2T 1C", "6T 1C", "7T 1C", "6T 2C", or "7T 2C". Here, "T" represents a transistor, the number located in front of "T" represents the number of transistors, "C" represents a capacitor, and the number located in front of "C" represents the number of capacitors. Wherein one transistor may include: source 132s, drain 132d, and gate 132 g. The driving circuit 132 may further include a first metal layer m1 coupled with the pixel driving circuit, for example, the first metal layer m1 is coupled with one transistor in the pixel driving circuit through a first contact hole 132c, wherein the first contact hole 132c may be filled with tungsten or other metal. The driving circuit 132 may further include a second metal layer m2 coupled to the first metal layer m1, for example, the first metal layer m1 is coupled to the second metal layer m2 through a second contact hole 132w, so that a data signal (e.g., a data voltage) provided by the pixel driving circuit is applied to the first electrode 111 through the first contact hole 132c, the first metal layer m1, the second metal layer m2, and the second contact hole 132 w. OLEDs disposed on a silicon substrate may be referred to as silicon-based OLEDs. Since the silicon substrate is opaque, the silicon-based OLED may be a top-emission type OLED capable of emitting light to a side facing away from the silicon substrate 131.

Specifically, the structure of the light emitting device is explained by taking a top emission type silicon-based OLED as an example. With continued reference to fig. 2A, the top-emission type silicon-based OLED may include a first electrode 111 and a second electrode 112 disposed opposite to each other, and a light emitting functional layer 113 disposed between the first electrode 111 and the second electrode 112. In the display panel 1, a pixel defining layer 114 may be further disposed on the driving backplane 130 and configured to separate adjacent light emitting devices to reduce leakage current.

Here, the first electrode 111 may be an anode, for example. In one example, referring to fig. 2A, the first electrode 111 itself may reflect light, for example, when the first electrode 111 includes a metal pattern, the first electrode 111 may reflect light. The first electrode 111 may be a stacked structure, that is, a stacked structure including a plurality of (at least two) conductive patterns stacked, for example, the first electrode 111 is a stacked structure of Ti/Al/Ti, Ti/Al/Ti/Mo, or Ti/Ag/ITO; wherein, Ti/Al/Ti refers to a laminated structure formed by three conductive patterns, and the materials of the three conductive patterns are Ti, Al and Ti in sequence according to the direction close to the second electrode 112; other stack structures may also be explained with reference to this document. At this time, the first electrode 111 may be a light reflecting layer. In another example, referring to fig. 2B, the first electrode 111 may be a transparent conductive layer, for example made of ITO, and a light reflective layer may be further disposed on a side of the first electrode 111 away from the second electrode 112, for example, the second metal layer m2 is configured as a light reflective layer, so that in the silicon-based OLED, the light reflective layer may reflect light. Accordingly, the second electrode 112 may be a cathode, and the material thereof may be a metal or an alloy, for example, Al, Mg, Ag. The second electrode 112 may be a translucent electrode (also referred to as a semi-transmissive electrode). Also illustratively, the first electrode 111 may be a cathode and the second electrode 112 may be an anode.

Thus, in the silicon-based OLED, a microcavity structure may be formed between the light reflective layer (e.g., the first electrode 111 or the first electrode 111 disposed on a side away from the second electrode 112) and the second electrode 112. The microcavity structure has a microcavity effect, and can selectively enhance light with a specific wavelength in the light emitted from the light-emitting functional layer 113 in the silicon-based OLED, and suppress light with other wavelengths. The wavelength of light that the microcavity can enhance can be characterized by a microcavity emission peak wavelength in the spectrum of light emitted by the light-emitting device, e.g., the microcavity can selectively enhance light having a wavelength of Ynm, and the microcavity emission peak wavelength can be Ynm in the spectrum of light emitted by the light-emitting device that includes the microcavity.

In the display panel provided by the embodiment of the present disclosure, when a voltage is applied to the light emitting device in a sub-pixel, the sub-pixel may emit light. When the maximum gray scale voltage corresponding to the sub-pixel is applied to the sub-pixel, the area where the sub-pixel can emit light is called an actual light emitting area. Specifically, for a sub-pixel, the maximum gray scale voltage corresponding to the sub-pixel may be the voltage applied to the sub-pixel when the gray scale data of the sub-pixel is 255. Taking the first sub-pixel 10 in fig. 2A as an example, the actual light emitting region thereof may be the region Aa. Also as described above, a microcavity may be formed in the light emitting device 110. Based on this, the actual emission region Aa of the first sub-pixel 10 can be divided into the central emission region Ca and the edge emission region Ea, wherein the first sub-pixel 10 can form a microcavity having a uniform cavity length in the central emission region Ca; accordingly, the edge light-emitting area Ea is an area other than the center light-emitting area Ca in the actual light-emitting area Aa.

Referring to fig. 2A and 2B, the cavity length of the microcavity may be directly proportional to the distance d between the light reflecting layer and the second electrode 112, and in this case, the microcavity of the first subpixel 10 in the central light-emitting region Ca has a uniform cavity length meaning that: in the first sub-pixel 10, the reflective layer is substantially parallel to the second electrode 112 in the central emission region Ca. In the embodiment of the present invention, the two (e.g., the light reflecting layer and the second electrode 112) are substantially parallel to each other, which means: the difference between the maximum distance and the minimum distance is less than or equal to the product of the minimum distance and a set proportion, wherein the set proportion can be set according to actual needs, such as 20%, 10%, 8%, 5%, and the like. In one example, referring to fig. 2A, the light reflective layer is the first electrode 111, and the central light-emitting region Ca of the sub-pixel 10 is the region of the sub-pixel 10 where the first electrode 111 and the second electrode 112 are substantially parallel. In another example, referring to fig. 2B, a light reflecting layer (e.g., the second metal layer m2) is disposed on a side of the first electrode 111 away from the second electrode 112, the light reflecting layer and the first electrode 111 may be substantially parallel, and then the central light-emitting area Ca of the sub-pixel 10 may also be a region where the first electrode 111 and the second electrode 112 are substantially parallel.

In some possible implementations, the central light-emitting region Ca may be a region corresponding to the first electrode 111 exposed by the pixel defining layer 114; specifically, the pixel defining layer 114 is provided with openings 114a, and one opening 114a exposes at least a portion of one of the first electrodes 111, and at this time, a lower edge (edge close to the first electrode 111) of the opening 114a determines an edge of the central light-emitting region Ca. In other possible implementations, referring to fig. 2C, the central light-emitting region Ca may be a region corresponding to a portion of the second electrode 112 that is concave and flat toward the first electrode 111.

As for the central light-emitting region Ca, since the light-reflecting layer located in the central light-emitting region Ca and the second electrode 112 are substantially parallel, a microcavity structure having a uniform cavity length can be formed therebetween, and thus, the light intensity of a specific wavelength band in the light emitted from the light-emitting functional layer 113 can be enhanced. Further, a microcavity emission peak (which means an emission peak corresponding to a wavelength at which the microcavity is enhanced) exists in the spectrum of the light emitted from the central light-emitting region Ca. For the edge emitting region Ea, since the cavity length of the microcavity is changed or the microcavity structure is not present, the microcavity effect of the edge emitting region Ea is reduced or absent, and it can be considered that the desired microcavity effect is not present in the edge emitting region Ea, so that an intrinsic emission peak is present in the spectrum of the light emitted by the edge emitting region Ea without a microcavity emission peak.

The microcavity effect can be utilized to adjust the light emitting characteristics of the light emitting device. Exemplarily, referring to fig. 3, in the intrinsic spectrum of the white OLED, the intensity of blue light is small compared to green and red light. By adjusting the microcavity structure of the OLED in the blue sub-pixel, for example, adjusting the microcavity length of the OLED, light in a blue wavelength band in the OLED of the blue sub-pixel can be enhanced, and the intensity of blue light emitted by the blue sub-pixel is further improved.

Further, the microcavity structures of the light emitting devices in the blue sub-pixel, the green sub-pixel, and the red sub-pixel may be respectively set (for example, the microcavity length of the OLED is set), so that the light emitting intensities of the blue sub-pixel, the green sub-pixel, and the red sub-pixel may be adjusted according to actual needs. Illustratively, to match the color-resolving power of the human eye, and in accordance with the standard NTSC (National Television Standards Committee) of conventional displays, when designing the microcavity structure for the blue, green and red sub-pixels, it is desirable that the microcavity emission peak wavelength for the blue sub-pixel be between 455nm and 465nm, such as 460 nm; the microcavity emission peak wavelength of the green sub-pixel is between 520nm and 545nm, for example 530 nm; the microcavity emission peak wavelength of the red sub-pixel is between 620nm and 640nm, such as 620nm or 630 nm.

However, for silicon-based OLED display devices, the resolution is generally higher, for example, over 3000ppi (pixel per inch, number of pixels in a diagonal) resolution. To achieve such resolution, the size of the sub-pixels in the silicon-based OLED display device is required to be small. For example, in the case of a rectangular sub-pixel (the rectangular sub-pixel may be a sub-pixel in which the central light-emitting region is rectangular), the length or width of at least one side thereof (for example, one side of the central light-emitting region) is 5 μm or less; for a circular sub-pixel (which may be a sub-pixel having a circular central light emitting area), its diameter (which may be the diameter of the central light emitting area of the circular sub-pixel) is below 5 μm, e.g. 3.7 μm or 2.5 μm. Due to the fact that the size of the sub-pixels is small, when the micro-cavity structure of the white OLED in the sub-pixels is designed, considering process difficulty, manufacturing time and manufacturing cost, it is technically difficult to design proper micro-cavity lengths for the sub-pixels with different colors respectively. In the practical production of the silicon-based OLED display device, the microcavity lengths of the light-emitting devices in the blue sub-pixel, the green sub-pixel and the red sub-pixel can be uniformly set, so that under the microcavity effect, the microcavity emission peak exists in the blue light wave band of the light emitted by the light-emitting devices in the blue sub-pixel, and the intensity of the blue light emitted by the blue sub-pixel is further increased; the light emitted by the light-emitting device in the green sub-pixel has a microcavity emission peak in a green light band, so that the intensity of green light emitted by the green sub-pixel is increased; and the light emitted by the light-emitting device in the red sub-pixel has a microcavity emission peak in a red light band, so that the intensity of red light emitted by the red sub-pixel is increased.

Further, when the micro-cavity lengths of the white OLEDs in the blue sub-pixel, the green sub-pixel, and the red sub-pixel are uniformly set, the design of the micro-cavity lengths of the white OLEDs preferably satisfies the requirements of the blue sub-pixel and the green sub-pixel, so that the micro-cavity emission peak wavelength is substantially the same as the intrinsic peak wavelength. For example, the microcavity length may be set so that the microcavity emission peak wavelength in the blue wavelength band is 460nm and the microcavity emission peak wavelength in the green wavelength band is 520nm to 540nm in the spectrum of light emitted from the light-emitting device. However, in this case, after the design of the microcavity length of the white OLED preferentially satisfies the requirements of the blue sub-pixel and the green sub-pixel, the requirement of the red sub-pixel may not be satisfied, and the microcavity emission peak wavelength in the red band may deviate from the range of the intrinsic emission peak wavelength (620nm to 640nm), for example, the microcavity emission peak wavelength in the red band is 680nm, and the intrinsic emission peak wavelength in the red band is 620 nm. At this time, since the central light emitting region of the red sub-pixel has the microcavity effect, in the spectrum of light emitted from the central light emitting region, a microcavity emission peak exists in a red wavelength band, and the peak wavelength thereof is 680 nm; and the microcavity effect does not exist in the edge light emitting region, and the emission of the edge light emitting region has an intrinsic emission peak in a red light wave band, and the peak wavelength of the emission peak is 620 nm. Thus, in the red sub-pixel, the spectral peak wavelength (microcavity emission peak wavelength) of the emission from the central emission region is different from the spectral peak wavelength (intrinsic peak wavelength) of the emission from the edge emission region. And for the blue and green sub-pixels, the spectral peak wavelength (microcavity emission peak wavelength) of the light emitted from the central light-emitting region is the same as the spectral peak wavelength (intrinsic peak wavelength) of the light emitted from the edge light-emitting region.

In some embodiments of the present disclosure, there is provided a display panel in which a microcavity length of a light emitting device in a first sub-pixel and a microcavity length of a light emitting device in a second sub-pixel may be the same. And the spectral peak wavelength of the first color light emitted from the central light-emitting region of the first sub-pixel is substantially the same as the spectral peak wavelength of the first color light emitted from the edge light-emitting region of the first sub-pixel; the spectral peak wavelength of the second color light emitted from the central light-emitting area of the second sub-pixel is different from the spectral peak wavelength of the second color light emitted from the edge light-emitting area of the second sub-pixel. Wherein, the two peak wavelengths are different, which means that the absolute value of the difference value of the two peak wavelengths is larger than 30 nm. Accordingly, the two peak wavelengths being substantially equal may mean that an absolute value of a difference of the two peak wavelengths is less than or equal to 30 nm. In some possible implementations, the microcavity length of the light-emitting device in the first sub-pixel, the microcavity length of the light-emitting device in the second sub-pixel, and the microcavity length of the light-emitting device in the third sub-pixel may all be the same. And, the spectral peak wavelength of the third color light emitted from the central light emitting region of the third sub-pixel is substantially the same as the spectral peak wavelength of the first color light emitted from the edge light emitting region of the third sub-pixel.

Illustratively, the first sub-pixel is a blue sub-pixel, the second sub-pixel is a red sub-pixel, and the third sub-pixel is a green sub-pixel. For the blue sub-pixel, the edge emitting region has no microcavity effect, and the spectral peak wavelength of the emitted light includes the intrinsic emission peak wavelength, e.g., 460 nm; the central light-emitting region emits light under the microcavity effect at spectral peak wavelengths including the microcavity emission peak wavelength, e.g., 460nm, and the peak wavelengths of the light-emitting regions emit light at about the same wavelength. For the green sub-pixel, the edge emitting region has no microcavity effect, and the spectral peak wavelength of the emitted light includes the intrinsic emission peak wavelength, e.g., 530 nm; the central light-emitting region emits light under the microcavity effect at spectral peak wavelengths including the microcavity emission peak wavelength, e.g., 530nm, and the spectral peak wavelengths of the light-emitting regions emit light at about the same wavelength. However, for the red sub-pixel, the edge emitting region has no microcavity effect, and the spectral peak wavelength of the emitted light includes the intrinsic emission peak wavelength, e.g., 620 nm; the central light-emitting region emits light under the microcavity effect at a peak wavelength in the spectrum of the light including the microcavity emission peak wavelength, e.g., 680nm, and the spectral peak wavelengths of the light emitted by the two light-emitting regions may not be the same. Illustratively, the central light-emitting region, under the microcavity effect, may include multiple peaks in the spectrum of the emitted light, at least one of which is a peak enhanced by the microcavity effect, which may be referred to as a microcavity emission peak. When the absolute value of the difference between the peak wavelength of the microcavity emission and the peak wavelength of the intrinsic emission peak in the spectrum of the light emitted by the edge light-emitting region is greater than 30nm, the peak wavelength of the spectrum of the light emitted by the center light-emitting region is said to be different from the peak wavelength of the spectrum of the light emitted by the edge light-emitting region.

Thus, in a pixel, the spectral peak wavelengths of light emitted by the central light-emitting region and the edge light-emitting region are substantially the same for the first sub-pixel (e.g., blue sub-pixel and green sub-pixel); whereas for the second sub-pixel (e.g., the red sub-pixel), the spectral peak wavelengths of the light emitted from the central light-emitting region and the edge light-emitting region are different. Fig. 4 shows, for example, the red sub-pixel, the luminance of the light emitted from the sub-pixel as a function of the viewing angle in both cases where the spectral peak wavelengths of the light emitted from the central light-emitting region and the edge light-emitting region are approximately the same and where the spectral peak wavelengths of the light emitted from the central light-emitting region and the edge light-emitting region are different. Referring to fig. 4, as the side view angle increases, the luminance of the sub-pixels with substantially the same peak wavelength of the spectrums emitted by the central light-emitting area and the edge light-emitting area steadily decreases, and the luminance of the sub-pixels with different peak wavelengths of the spectrums emitted by the central light-emitting area and the edge light-emitting area steadily decreases and then increases under the combined action of the two areas. As the brightness attenuation trends of the first sub-pixel and the second sub-pixel are different along with the increase of the side viewing angle, the color block displayed by the pixel comprising the first sub-pixel and the second sub-pixel has the color cast phenomenon under the large side viewing angle, and further, the color cast phenomenon exists on the picture displayed by the display panel under the large side viewing angle.

The color shift problem can be improved by adjusting the relationship between the central light-emitting area and the edge light-emitting area of a sub-pixel. When the spectral peak wavelengths of the light emitted by the central light-emitting area and the edge light-emitting area of a sub-pixel are different, the influence of the edge light-emitting area can be increased by reducing the influence of the central light-emitting area, and the brightness attenuation trend of the sub-pixel along with the increase of the side viewing angle can be adjusted. For example, the area of the central light-emitting area can be reduced and/or the area of the edge light-emitting area can be increased, so that the influence of the central light-emitting area can be reduced, the influence of the edge light-emitting area can be increased, and the brightness attenuation tendency of the sub-pixel along with the increase of the side viewing angle can be adjusted.

For convenience of description, when the maximum grayscale voltage corresponding to a sub-pixel is applied to the sub-pixel, the ratio of the area of the central light-emitting region of the sub-pixel to the area of the edge light-emitting region of the sub-pixel is the area ratio of the sub-pixel, where the area of the central light-emitting region can be denoted as C, the area of the edge light-emitting region can be denoted as E, and the area ratio of a sub-pixel can be denoted as C/E.

On this basis, fig. 5 illustrates, for example, a red sub-pixel including an OLED emitting red light (hereinafter referred to as a red OLED), the influence of the ratio of the area of the central light-emitting region and the area of the edge light-emitting region of a sub-pixel on the spectral peak wavelength of light emitted from the sub-pixel. Then, reference is also made to this figure for the emission of red spectra by the subpixels of the white OLED in combination with the red color film pattern. Wherein the thickness of the light-emitting functional layer in the red OLED is 300nm, the central light-emitting region of the sub-pixel is circular, the diameters of the circular central light-emitting region are 2 μm, 3.1 μm and 4.0 μm respectively, the maximum gray scale voltage applied to the sub-pixel is 9V (for example, the voltage difference between the cathode and the anode of the sub-pixel is set to 9V), the area ratio C/E of the sub-pixel is 5.1 (corresponding to a diameter of 2 μm), 8.0 (corresponding to a diameter of 3.1 μm) and 10.2 (corresponding to a diameter of 4.0 μm) respectively, the microcavity of the sub-pixel is configured to enhance light with a wavelength of 680nm, that is, the spectrum of the light emitted from the central light-emitting region may include a microcavity emission peak with a peak wavelength of 680 nm; and the intrinsic emission peak wavelength of the red light emitting material is 620 nm. Referring to fig. 5, in the red OLED, a peak in the spectrum of the red light emitting material is an intrinsic emission peak of the red OLED. The larger the area ratio C/E of a sub-pixel, the greater the intensity of the microcavity emission peak and the smaller the intensity of the intrinsic emission peak in the spectrum of the emitted light (i.e., the spectrum of the light emitted by the sub-pixel as a whole), i.e., the larger the area ratio C/E of a sub-pixel, the greater the influence of the central light-emitting area of the sub-pixel, and the greater the influence of the area having the microcavity effect. Conversely, the smaller the area ratio C/E of a sub-pixel, the greater the intensity of the intrinsic emission peak and the smaller the intensity of the microcavity emission peak in the spectrum of the emitted light, i.e., the smaller the area ratio C/E of a sub-pixel, the greater the influence of the edge light-emitting region of the sub-pixel, and the greater the influence of the region without microcavity effect. It can be seen that adjusting the area ratio C/E of a sub-pixel can adjust the magnitude of the influence of the region with microcavity effect and the influence of the region without microcavity effect in the sub-pixel.

Further, fig. 6 shows that in the case where the spectral peak wavelength of the second color light emitted from the central emission region of the second sub-pixel is not the same as the spectral peak wavelength of the second color light emitted from the edge emission region of the second sub-pixel, when the area ratio C/E of the second sub-pixel is different, the tendency that the luminance of the second sub-pixel attenuates as the viewing angle becomes larger is also different. Referring to fig. 6, when the area ratio C/E of the second sub-pixel is decreased, the influence of the edge light-emitting region in the second sub-pixel becomes large and the influence of the center light-emitting region, i.e., the region having the microcavity effect becomes small. Under the combined action of the first sub-pixel and the second sub-pixel, the brightness of the second sub-pixel can be stably reduced in a larger viewing angle range. Therefore, for a pixel, the brightness of the first sub-pixel and the second sub-pixel included in the pixel can be stably reduced in a larger visual angle range, namely, the brightness attenuation trends of the first sub-pixel and the second sub-pixel can be matched in the larger visual angle range, and the color cast phenomenon of a color block displayed by the pixel can be further improved.

In some embodiments, referring to fig. 2A, the area C of the central light emitting region Ca may be the area of the first electrode 111 exposed by the pixel defining layer 114. The area a of the actual light-emitting area Aa of the sub-pixel may be measured with reference to a point where the actual light-emitting area Aa of the sub-pixel is determined by applying the corresponding maximum gray scale voltage to the sub-pixel, lighting the sub-pixel, and measuring the actual light-emitting area Aa of the sub-pixel, for example, by attenuating the luminance to x% (x ≧ 10, for example, x ═ 10, 20, 30, 40, 50) of the center luminance of the sub-pixel as the boundary of the actual light-emitting area Aa of the sub-pixel. Accordingly, the area E of the edge light-emitting area Ea of the sub-pixel may be the difference between the area a of the actual light-emitting area Aa and the area C of the center light-emitting area Ca.

In other embodiments, the area E of the edge light-emitting area Ea may be a product of the circumference of the center light-emitting area Ca and a width parameter. Wherein, the circumference of the central light-emitting region Ca may be the circumference of the orthographic projection of the central light-emitting region Ca on the first electrode 111; the circumference of the central light emitting region Ca may also be the circumference of the first electrode 111 where the pixel defining layer 114 is exposed, i.e., the circumference of the lower edge of the opening 114a of the pixel defining layer 114. Referring to fig. 2A, the width parameter may be obtained according to the thickness of the light-emitting functional layer 113 in the sub-pixel and the maximum gray scale voltage corresponding to the sub-pixel. Illustratively, referring to fig. 7, the width parameter may be obtained according to the thickness of the specific light-emitting functional layer and the maximum gray scale voltage corresponding to the sub-pixel.

In the display panel provided by the embodiment of the present disclosure, the area ratio of the second sub-pixel (e.g., the red sub-pixel) is less than or equal to 15. At this time, the brightness of the second sub-pixel can be stably reduced in a larger viewing angle range, and further, the color shift problem of the display screen of the display panel under a large viewing angle can be improved. Exemplarily, the area ratio of the second sub-pixel is less than or equal to 10; still further illustratively, the area ratio of the second sub-pixel is less than or equal to 8. The area ratio of the second sub-pixel is, for example, 10, 9, 8, 7, 6, 5, 4, or 3.

In some embodiments, the area ratio of the first sub-pixel is greater than the area ratio of the second sub-pixel. When the area ratio of a sub-pixel is large, the influence of the central light-emitting region, i.e., the region having the microcavity effect, is large, and when the area ratio of the sub-pixel is large, the microcavity effect in the sub-pixel is stronger, compared to the case where the area ratio of the sub-pixel is small, so that the intensity of light emitted by the sub-pixel is larger. When the area of the second sub-pixel is smaller and the area of the first sub-pixel is larger, the color cast problem of the display picture of the display panel under a larger side viewing angle can be improved, and the brightness of the display picture of the display panel can be improved. In some possible implementations, the area of the central light emitting area of the first sub-pixel is larger than the area of the central light emitting area of the second sub-pixel. In this way, in the first sub-pixel, the light emitting area under the action of the microcavity effect is larger, so that the intensity of light emitted by the first sub-pixel is larger, and the brightness of a display picture of the display panel can be further improved.

In some embodiments, the resolution of the display panel is greater than or equal to 3500 ppi. The resolution of the display panel is an actual resolution (also referred to as a physical resolution), and the logical resolution including the virtual pixels is not considered. I.e. how many first sub-pixels per diagonal of an inch the display panel comprises, then how large the resolution the display panel has accordingly. When the resolution of the display panel is greater than or equal to 3500ppi, the size of the sub-pixel in the display panel is small, and the influence of the edge light-emitting region in one sub-pixel is large, so that the area ratio of the central light-emitting region and the edge light-emitting region is more likely to fall within the range defined by the embodiment of the present disclosure.

In some embodiments, the thickness of the light emitting functional layer is greater than or equal to 300 nm. As described above, the area ratio of the sub-pixels is related to the thickness. Specifically, fig. 8 shows a relationship between the resolution of the display panel and the area ratio of the sub-pixels at different thicknesses of the light emitting function layer (denoted as EL in the figure) when the maximum grayscale voltage of the sub-pixels is 9V. Fig. 9 shows the corresponding C/E values versus resolution for different thicknesses of the light-emitting functional layer (100nm, 300nm, and 500 nm). Referring to fig. 8 and 9, when the thickness of the light emitting function layer is increased, the area ratio C/E of the sub-pixel is decreased significantly, and may fall within the range defined by the embodiments of the present disclosure with a smaller resolution.

In some embodiments, the edges of the central light emitting area in a sub-pixel are circular, elliptical, or polygonal. The polygon may be an axisymmetric figure, and may be a quadrangle, a pentagon, a hexagon, etc., having at least one axis of symmetry. Further, the polygon may be a regular polygon, such as a regular hexagon, or the like. At this time, the arrangement of the sub-pixels can be more compact. In addition, the three primary color sub-pixels can be arranged in a triangular shape, so that one sub-pixel is shared by a plurality of logic pixels (also called as virtual pixels), the logic resolution of the display panel is improved, and the display quality of the display panel is improved.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, and not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims

1. A display panel, comprising:

a plurality of sub-pixels, an actual light-emitting area of a sub-pixel including a central light-emitting area in which the sub-pixels form a micro-cavity having a uniform cavity length and an edge light-emitting area which is an area of the actual light-emitting area other than the central light-emitting area; the actual light-emitting area of the sub-pixel is an area which can emit light when the sub-pixel is applied with the maximum gray scale voltage corresponding to the sub-pixel, and the area ratio of the central light-emitting area of the sub-pixel to the area of the edge light-emitting area of the sub-pixel is the area ratio of the sub-pixel;

the plurality of sub-pixels includes a first sub-pixel configured to emit a first color light and a second sub-pixel configured to emit a second color light;

a spectral peak wavelength of the first color light emitted from the central light-emitting area of the first subpixel is substantially the same as a spectral peak wavelength of the first color light emitted from the edge light-emitting area of the first subpixel; a spectral peak wavelength of the second color light emitted from the central light-emitting area of the second sub-pixel is different from a spectral peak wavelength of the second color light emitted from the edge light-emitting area of the second sub-pixel;

the area ratio of the second sub-pixel is less than or equal to 15.

2. The display panel according to claim 1,

the area ratio of the second sub-pixel is less than or equal to 10.

3. The display panel according to claim 1,

the area ratio of the first sub-pixel is larger than the area ratio of the second sub-pixel.

4. The display panel according to claim 1,

the area of the central light-emitting area of the first sub-pixel is larger than that of the central light-emitting area of the second sub-pixel.

5. The display panel of claim 1, wherein the plurality of sub-pixels further comprises:

a third sub-pixel configured to emit a third color light;

a spectral peak wavelength of the third color light emitted from the central light-emitting area of the third sub-pixel is substantially the same as a spectral peak wavelength of the third color light emitted from the edge light-emitting area of the third sub-pixel;

the area ratio of the third sub-pixel is larger than the area ratio of the second sub-pixel.

6. The display panel according to claim 1,

the second color light emitted by the second sub-pixel is red light.

7. The display panel of claim 1, wherein a sub-pixel comprises: a light emitting device configured to emit white light and a color film pattern.

8. The display panel according to claim 7, wherein the light-emitting device comprises: the light-emitting device comprises a first electrode, a second electrode and a light-emitting functional layer, wherein the first electrode and the second electrode are oppositely arranged, and the light-emitting functional layer is arranged between the first electrode and the second electrode;

in one sub-pixel, the area of the edge light-emitting region is the product of the perimeter of the central light-emitting region and a width parameter, and the width parameter is obtained according to the thickness of a light-emitting functional layer in the sub-pixel and the maximum gray scale voltage corresponding to the sub-pixel.

9. The display panel according to claim 8,

the thickness of the light-emitting functional layer is greater than or equal to 300 nm.

10. The display panel according to claim 7, further comprising:

a driving backplane configured to carry the light emitting devices in the plurality of sub-pixels;

the driving back plate comprises a silicon substrate and at least one pixel driving circuit arranged on the silicon substrate, wherein one pixel driving circuit is coupled with a light emitting device in one sub-pixel.

11. The display panel according to any one of claims 1 to 10,

the resolution of the display panel is greater than or equal to 3500 ppi.

12. The display panel according to claim 1,

the edge of the central light-emitting area in a sub-pixel is circular, elliptical or polygonal.

13. A display device comprising the display panel according to any one of claims 1 to 12.