Foldable display screen and display device

Abstract

The application belongs to the technical field of display, and provides a foldable display screen and a display device. The foldable display substrate in the foldable display screen comprises a driving layer and a light-emitting layer. The light-emitting layer comprises a plurality of pixel units arranged in an array. Each pixel unit comprises a first sub-pixel, a second sub-pixel and a third sub-pixel. The second sub-pixel is located between the first sub-pixel and the third sub-pixel. The foldable display substrate has a bendable area and a non-bendable area adjacent to the bendable area. The optical functional layer in the foldable display screen comprises an encapsulation layer and a touch layer. The encapsulation layer comprises a first organic film. The touch layer comprises a second organic film. The refractive index of the second organic film is greater than the refractive index of the first organic film. The optical functional layer is used to reduce the difference between the light-emitting angle of at least part of the sub-pixels in the bendable area from the light-emitting surface of the optical functional layer and the light-emitting angle of the sub-pixels in the non-bendable area from the light-emitting surface of the optical functional layer. The foldable display screen provided by the application can reduce the crease effect of the bendable area.

Description

Technical Field

[0001] This application belongs to the field of display technology, and in particular relates to a foldable display screen and display device. Background Technology

[0002] With the development of technology, the functions of displays in display devices have become increasingly powerful, requiring corresponding increases in display size to provide users with more information and operations. However, the increased display size has severely impacted the portability of display devices. To enable display devices with larger or even larger screens while still being easy for users to carry, after many years of unremitting efforts, foldable displays have emerged on the market.

[0003] The cover plates and support plates used in current foldable displays are often made of polymer materials. Whether the display is folded in a U-shape or a teardrop shape, the polymer materials will undergo plastic deformation under long-term repeated bending, inevitably leading to creases. Furthermore, after prolonged bending, the optically clear adhesive (OCA) in the foldable display will flow and accumulate, also contributing to creases. As usage time increases, these creases become more pronounced, severely impacting the display's aesthetic appeal and performance. Summary of the Invention

[0004] The purpose of this application is to provide a foldable display screen and a display device. The foldable display screen has a screen design that reduces the crease effect in the bendable area, resulting in high product quality and good market competitiveness.

[0005] A first aspect of this application provides a foldable display screen, including:

[0006] A foldable display substrate includes a driving layer and a light-emitting layer disposed on one side of the driving layer. The light-emitting layer includes a plurality of pixel units arranged in an array. Each pixel unit includes a first sub-pixel, a second sub-pixel, and a third sub-pixel. The second sub-pixel is located between the first sub-pixel and the third sub-pixel. The foldable display substrate has a bendable region and a non-bendable region adjacent to the bendable region.

[0007] An optical functional layer is disposed on the light-emitting side of the light-emitting layer. The optical functional layer includes an encapsulation layer and a touch layer. The touch layer is disposed on the side of the encapsulation layer away from the light-emitting layer. The encapsulation layer includes a first organic film, and the touch layer includes a second organic film. The refractive index of the second organic film is greater than that of the first organic film. The optical functional layer is used to reduce the difference between the light emission angle of at least a portion of the sub-pixels in the bendable region from the light-emitting surface of the optical functional layer and the light emission angle of the sub-pixels in the non-bendable region from the light-emitting surface of the optical functional layer. There is a first distance and a second distance between the light rays emitted from the light-emitting surfaces of the first and third sub-pixels and the light rays emitted from the light-emitting surfaces of the second sub-pixel. There is a first spacing and a second spacing between the first and third sub-pixels and their adjacent non-bendable regions in a direction parallel to the light-emitting layer. The optical functional layer has a first thickness in a direction perpendicular to the light-emitting layer.

[0008] Through the above technical solution, the optical functional layer has a first organic layer and a second organic layer in the bendable area. The second organic layer is located on the light-emitting side of the first organic layer, and the refractive index of the first organic layer is less than that of the second organic layer. Based on the principle that the incident angle of light in a medium with a low refractive index is greater than the exit angle of light in a medium with a high refractive index, the light emission angle of at least some sub-pixels located in the bendable area on the light-emitting surface of the foldable display can be adjusted. That is, by changing the screen structure, the light emission path is changed, thereby reducing the difference between the light emission angle of at least some sub-pixels in the bendable area and the light emission angle of sub-pixels in the non-bendable area. This changes the optical display effect, reduces the perceptual difference between the bendable and non-bendable areas, thereby reducing the crease appearance in the bendable area of ​​the foldable display, improving the display effect of the foldable display, and providing a better user experience. At the same time, by using the original encapsulation layer and touch layer in the foldable display as the optical functional layer, the thickness and cost of the foldable display can be reduced.

[0009] Thus, the foldable display screen provided in this application embodiment has a screen design that reduces the crease effect in the bendable area, which is beneficial for industrial production and application.

[0010] In some embodiments, the optical functional layer further includes a third organic film disposed on the side of the touch layer away from the light-emitting layer, and the refractive index of the third organic film is greater than that of the second organic film.

[0011] In some embodiments, the third organic membrane includes at least one submembrane.

[0012] In some embodiments, when the third organic film comprises multiple sub-films, the refractive index of the multiple sub-films increases sequentially along the light emission direction of the light-emitting layer.

[0013] In some embodiments, the foldable display screen further includes a lens layer disposed on the side of the optical functional layer away from the light-emitting layer. The lens layer includes a plurality of convex lenses arranged in an array, the center of each convex lens coinciding with the light-emitting point of the light emitted from the light-emitting surface of each sub-pixel from the optical functional layer.

[0014] In some implementations, there is a third distance between the light rays emitted from the light-emitting surface of the first sub-pixel and the light rays emitted from the light-emitting surface of the second sub-pixel, and there is a fourth distance between the light rays emitted from the light-emitting surface of the third sub-pixel and the light rays emitted from the light-emitting surface of the second sub-pixel.

[0015] The third distance is greater than the first distance, and the fourth distance is greater than the second distance.

[0016] In some embodiments, the foldable display substrate includes a first non-bending region, a bendable region, and a second non-bending region. The first non-bending region is connected to the bendable region and the second non-bending region. A third spacing is provided between the first sub-pixel and the first non-bending region along a direction parallel to the light-emitting layer. A fourth spacing is provided between the third sub-pixel and the second non-bending region along a direction parallel to the light-emitting layer. The third spacing is smaller than the first spacing, and the fourth spacing is smaller than the second spacing.

[0017] In some embodiments, the optical functional layer has a second thickness along a direction perpendicular to the light-emitting layer, the second thickness being less than the first thickness.

[0018] In some implementations, the first sub-pixel is a red sub-pixel, the second sub-pixel is a green sub-pixel, and the third sub-pixel is a blue sub-pixel.

[0019] A second aspect of this application provides a foldable display device, including the foldable display screen described above. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of a foldable display screen in a U-shaped bent state, which is part of a related technology.

[0022] Figure 2 This is a schematic diagram of a foldable display screen in a teardrop-shaped bent state, which is part of a related technology.

[0023] Figure 3This is a schematic diagram of the structure of a foldable display screen in its unfolded state after multiple bends, according to related technologies.

[0024] Figure 4 This is a schematic diagram of the structure of the first foldable display screen provided in the embodiments of this application;

[0025] Figure 5 This is a structural schematic diagram of a foldable display screen in related technologies;

[0026] Figure 6 This is a schematic diagram of the structure of the second foldable display screen provided in the embodiments of this application;

[0027] Figure 7 This is a structural schematic diagram of the third foldable display screen provided in the embodiments of this application;

[0028] Figure 8 This is a structural schematic diagram of the fourth foldable display screen provided in the embodiments of this application;

[0029] Figure 9 This is a structural schematic diagram of the fifth foldable display screen provided in the embodiments of this application. Detailed Implementation

[0030] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0031] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, this component can be directly on or indirectly on the other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to the other component.

[0032] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0033] Furthermore, the terms "first," "second," "third," "fourth," "fifth," and "sixth" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first," "second," "third," "fourth," "fifth," or "sixth" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0034] Most display devices today have screens, and with technological advancements, these screens are becoming increasingly powerful. As screen functionality increases, the required screen size also grows, enabling the provision of more information and operations for users, thus making the display device more powerful. However, the increased screen size significantly impacts the portability of display devices. For example, with a mobile phone, users typically want to hold it in one hand; if the screen is too large, it may be impossible to hold it with one hand. Therefore, after many years of effort, foldable displays have emerged to provide larger screens while maintaining portability. Foldable displays allow for more powerful functionality while reducing the device's size when folded, making it easier for users to carry.

[0035] Figure 1 A schematic diagram of a foldable display screen in a U-shaped bent state is shown in the related art. (Reference) Figure 1 As shown, the foldable display screen includes a bending portion 110 and non-bending portions 120 located on both sides of the bending portion 110. The non-bending portions 120 on both sides of the bending portion 110 are connected through the bending portion 110. The non-light-emitting layer in the non-bending portion 120 ( Figure 1 (Not shown in the image) is supported by support plate 130. Currently, most foldable displays on the market feature a U-shaped bend, but the U-shaped bend design has the following problems: In the U-shaped bend state, the support plates 130 located on both sides of the non-bend portion 120 of the foldable display are supported along the first direction (…). Figure 1 The spacing D1 in the oz direction is relatively large, resulting in a larger cover plate for the foldable display (in the oz direction). Figure 1 The large spacing between the U-shaped bends (not shown in the image) results in a thicker overall display device, such as a mobile phone, making it inconvenient for the user to hold. Furthermore, the U-shaped bends typically have a smaller bending angle at the center, leading to noticeable creases on the bend portion 110 after prolonged bending.

[0036] Figure 2 This diagram illustrates a foldable display screen in a teardrop-shaped bent state, according to related technologies. (Reference) Figure 2As shown, the teardrop-shaped bending state can increase the radius of the bending part 110 in the foldable display. This can reduce the thickness D2 of the foldable display after bending along the oz direction, and also effectively reduce the risk of breakage of the foldable display during bending, as well as the stress on the various film layers inside the foldable display, in order to reduce the crease depth and thus improve the bending performance of the foldable display.

[0037] Figure 3 This diagram illustrates a foldable display screen in its unfolded state after multiple folds, according to related technologies. (Reference) Figure 3 As shown, due to the cover plate used in current foldable displays ( Figure 3 (not shown in the image) and support plate ( Figure 3 (Not shown in the image) and other materials are often made of polymers. Even when foldable displays are bent into a teardrop shape, the polymers will undergo plastic deformation under long-term repeated bending, inevitably leading to creases. These creases become more pronounced over time. Furthermore, after prolonged bending, the OCA adhesive in the bending section 110 will flow and accumulate, which will also make the bending section 110 prone to creases. This severely affects the foldable display's refined appearance, resulting in poor performance and a poor user experience.

[0038] Based on the above, this application provides a foldable display screen. (See reference...) Figure 4 As shown, the foldable display screen provided in this application embodiment may include: a foldable display substrate 10 and an optical functional layer.

[0039] The foldable display substrate 10 may include a driving layer 11 and a light-emitting layer 12. The light-emitting layer 12 is disposed on one side of the driving layer 11 and includes a plurality of pixel units arranged in an array. Each pixel unit includes a first sub-pixel, a second sub-pixel, and a third sub-pixel arranged in an array. The second sub-pixel is located between the first sub-pixel and the third sub-pixel. The foldable display substrate 10 has a bendable region F and a non-bendable region E, and the bendable region F is adjacent to the non-bendable region E.

[0040] The optical functional layer may include an encapsulation layer 13 and a touch layer. The encapsulation layer 13 is disposed on the side of the light-emitting layer 12 away from the driving layer 11, and the touch layer is disposed on the side of the encapsulation layer 13 away from the light-emitting layer 12. The encapsulation layer 13 includes a first organic film 132, and the touch layer includes a second organic film 141. The refractive index of the second organic film 141 is greater than the refractive index of the first organic film 132. The optical functional layer is used to reduce the light emission angle of at least some sub-pixels in the bendable region F from the light-emitting surface of the optical functional layer and the light emission angle of sub-pixels in the non-bendable region E. The difference between the light emission angles of the light-emitting surfaces of the optical functional layer; there is a first distance d1 between the light emitted from the light-emitting surface of the first sub-pixel located in the bendable region F and the light emitted from the light-emitting surface of the second sub-pixel located in the bendable region F, and a second distance d2 between the light emitted from the light-emitting surface of the third sub-pixel located in the bendable region F and the light emitted from the light-emitting surface of the second sub-pixel located in the bendable region F, and the optical functional layer is perpendicular to the direction of the foldable display base 10. Figure 4 The first thickness is (in the oz direction).

[0041] In practical applications, the driving layer 11 can provide driving signals to the light-emitting layer 12 and play a role in buffering, protection, and support. The driving layer 11 may include a substrate and an array circuit disposed on the substrate. The specific type of substrate is not limited here. For example, the substrate may be a flexible substrate, which can be formed of any suitable insulating material with flexibility. For example, the material of the flexible substrate may include any one of polyimide (PI), polycarbonate (PC), polyethersulfone (PES), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and fiber reinforced plastics (FRP); or, the substrate may be a rigid substrate, such as a glass substrate, depending on the actual application.

[0042] The aforementioned light-emitting layer 12 includes multiple pixel units arranged in an array. Each pixel unit includes a first sub-pixel, a second sub-pixel, and a third sub-pixel arranged in an array. The color of each sub-pixel is not specifically limited. For example, the first sub-pixel can be a red sub-pixel, the second sub-pixel can be a green sub-pixel, and the third sub-pixel can be a blue sub-pixel; or, the first sub-pixel can be a green sub-pixel, the second sub-pixel can be a red sub-pixel, and the third sub-pixel can be a blue sub-pixel; or, the first sub-pixel can be a blue sub-pixel, the second sub-pixel can be a green sub-pixel, and the third sub-pixel can be a red sub-pixel; or, the first sub-pixel can be a red sub-pixel, the second sub-pixel can be a yellow sub-pixel, and the third sub-pixel can be a blue sub-pixel, etc., depending on the actual application. The following explanation uses the example of each pixel unit having a red sub-pixel, a green sub-pixel, and a green sub-pixel for the specific illustration.

[0043] The foldable display substrate 10 in this embodiment may further include a pixel delimiting layer surrounding the sub-pixels. The pixel delimiting layer has multiple pixel openings, and each sub-pixel is located in one pixel opening of the pixel delimiting layer. This avoids short circuits between different sub-pixels and delineates the boundary of each sub-pixel.

[0044] In this embodiment, the foldable display screen located in the bendable area F can be bent to achieve folding of the foldable display screen. Here, there are no specific limitations on the number and arrangement of the bendable area F and the non-bendable areas E. For example, the foldable display substrate 10 may have one bendable area F and two non-bendable areas E. Both non-bendable areas E are adjacent to the bendable area F, that is, the two non-bendable areas E are located on both sides of one bendable area F, and one non-bendable area E is connected to the other non-bendable area E through the bendable area F.

[0045] Furthermore, the foldable display substrate 10 may have an inner bendable region and two non-bendable regions E.

[0046] In practical applications, the optical functional layer is located on the light-emitting side of the light-emitting layer 12. Thus, the optical functional layer can be used to change the light-emitting angle of at least some sub-pixels in the light-emitting layer 12. Specifically, the optical functional layer can be used to change the light-emitting angle of at least some sub-pixels located in the bendable region F of the light-emitting layer 12, but not to change the light-emitting angle of any sub-pixels located in the non-bendable region E of the light-emitting layer 12.

[0047] It should be understood that the aforementioned optical functional layer used to reduce the difference between the light-emitting angle of at least some sub-pixels in the bendable region F and the light-emitting angle of sub-pixels in the non-bendable region E from the light-emitting surface of the optical functional layer refers to: (reference) Figure 4As shown, the light emitted from any one of the two non-bending regions E is perpendicular to the second organic film 141, and the light emitted from any one of the bendable regions F is also perpendicular to the second organic film 141. However, the difference is that the light emitted from any one of the two non-bending regions E enters the second organic film 141 perpendicular to the second organic film 141, while in the bendable region F, because the green sub-pixel is located in a relatively central position, and the red and blue sub-pixels are located on both sides of the green sub-pixel, due to the influence of bending angle, only the light emitted from the green sub-pixel enters the second organic film 141 perpendicular to the second organic film 141. However, the light emitted from the red and blue sub-pixels enters the second organic film 141 in a direction that is not perpendicular to the second organic film 141.

[0048] Based on this, the angle between the direction of the light emitted by the red sub-pixel and the direction of the blue sub-pixel in the optical functional layer and the oz direction can both be 25-30°. For details, refer to... Figure 4 As shown, the angle α1 between the direction of light emitted from the red sub-pixel entering and exiting the first organic film 132 and the oz direction can both be 25-30°, and the angle between the direction of light emitted from the red sub-pixel entering and exiting the second organic film 141 and the oz direction can both be 25-30°; similarly, the angle α2 between the direction of light emitted from the blue sub-pixel entering and exiting the first organic film 132 and the oz direction can both be 25-30°, and the angle between the direction of light emitted from the blue sub-pixel entering and exiting the second organic film 141 and the oz direction can both be 25-30°.

[0049] The aforementioned optical functional layer can be an existing film layer in the foldable display screen, or it can be a newly added film layer in the foldable display screen. In order to reduce the thickness and cost of the foldable display screen, this application embodiment uses the existing film layer in the foldable display screen as the optical functional layer. Specifically, this application embodiment uses at least the encapsulation layer 13 and the touch layer as optical functional layers.

[0050] In this embodiment of the application, there is a first distance d1 between the light emitted from the optical functional layer of the red sub-pixel located in the bendable region F and the light emitted from the optical functional layer of the green sub-pixel located in the bendable region F, and there is a second distance d2 between the light emitted from the optical functional layer of the blue sub-pixel located in the bendable region F and the light emitted from the optical functional layer of the green sub-pixel located in the bendable region F. d1 and d2 may be the same or different, and no specific limitation is made here.

[0051] In practical applications, the aforementioned encapsulation layer 13 can be a thin film encapsulation (TFE) layer. The TFE layer can be used to encapsulate pixel units and can protect the light-emitting layer 12 and other film layers from external moisture and oxygen, thereby extending the service life of the foldable display screen.

[0052] It should be understood that in the embodiments of this application, the encapsulation layer 13 is disposed on the side of the light-emitting layer 12 away from the driving layer 11, which means that the encapsulation layer 13 is located on the light-emitting side of the light-emitting layer 12.

[0053] It should be understood that the touch layer in this embodiment enables the foldable display to achieve touch functionality. The touch layer is located on the light-emitting side of the light-emitting layer 12, and this structure belongs to the On-cell touch structure. The specific structure of the touch layer is not limited here; exemplarily, the touch layer may also include a touch substrate (…). Figure 4 (Not shown in the image) The touch layer is disposed on the side of the touch substrate away from the light-emitting layer 12. Specifically, an indium tin oxide (ITO) layer can be directly deposited on the outside of the touch substrate on the first organic film 132; or, a transparent PET layer can be first disposed on the outside of the touch substrate, and then the transparent PET can be used as a substrate to form an ITO layer thereon. No specific limitation is made in this regard.

[0054] In practical applications, the materials of the first organic membrane 132 and the second organic membrane 141 can both be acrylic resin materials.

[0055] Furthermore, the first organic membrane 132 and the second organic membrane 141 can be fabricated using processes such as chemical vapor deposition (CVD).

[0056] In practical applications, the aforementioned foldable display screen can be a flexible display screen (also known as a flexible screen), and can be a foldable display screen with display function that can be folded and bent at will.

[0057] The display screen of a foldable phone can be used to display images and videos, etc. The display screen may include multiple screens, and the screens may be flexible screens. For example, the flexible screens may be any of the following: organic light-emitting diode (OLED) screens, mini light-emitting diode (Mini LED) screens, and micro light-emitting diode (Micro LED) screens, etc., without being specifically limited here.

[0058] Based on the above, the specific structure of the foldable display screen in the embodiments of this application is not limited, and the following is an exemplary description.

[0059] For example, a foldable display screen may include: a buffer layer, an active layer, a first insulating layer, a gate metal layer (including a gate and a first electrode), a second insulating layer, an electrode layer (including a second electrode), an interlayer dielectric layer, a source / drain metal layer (including a source and a drain), a planarization layer, and a pixel defining layer, which are sequentially stacked on a substrate. The first and second electrodes are used to form storage capacitors.

[0060] The red sub-pixel may include an anode and a hole injection layer, a hole transport layer, an electron blocking layer, a blue light-emitting layer, a hole blocking layer, an electron transport layer, an electron injection layer, and a cathode, which are stacked sequentially on the anode. In this case, the foldable display screen is a top-emitting type.

[0061] At least one encapsulation layer 13 and a touch layer are provided on the side of the cathode away from the substrate.

[0062] It should be noted that the green emitting layer in the green subpixel and the blue emitting layer in the blue subpixel are made of different materials than the red emitting layer in the red subpixel. The red emitting layer emits red light, the green emitting layer emits green light, and the blue emitting layer emits blue light. Furthermore, the electron blocking layer in the green subpixel and the electron blocking layer in the blue subpixel are also made of different materials than the electron blocking layer in the red subpixel. Apart from the color emitting layer and the electron blocking layer, the other film layers in the green and blue subpixels are the same as those in the red subpixel, and will not be described further here.

[0063] For example, Figure 5 This diagram illustrates the light propagation path of a foldable display screen in an inwardly folded state, according to related technologies. (Reference) Figure 5 As shown, when the inward-folding foldable display is bent and then flattened, it presents a V-shaped fold. At this time, the position of the light source in the bendable area F of the foldable display changes, which changes the way the light is emitted from the bendable area F. Specifically, the light emission path of the bendable area F is different from the vertical light emission of the non-bendable area E. The bendable area F no longer emits light perpendicularly to the light-emitting surface. Instead, some sub-pixels of the bendable area F emit light at an angle to the light-emitting surface, resulting in a difference in light perception.

[0064] Therefore, the foldable display screen provided in the embodiments of this application refers to Figure 4As shown, the optical functional layer has a first organic layer and a second organic layer in the bendable region F. The second organic layer is located on the light-emitting side of the first organic layer, and the refractive index of the first organic layer is less than that of the second organic layer. Based on the principle that the incident angle of light in a medium with a low refractive index is greater than the exit angle of light in a medium with a high refractive index, the light emission angle of at least some sub-pixels located in the bendable region on the light-emitting surface of the foldable display can be adjusted. That is, by changing the screen structure, the light emission path can be changed, thereby reducing the difference between the light emission angle of at least some sub-pixels in the bendable region and the light emission angle of sub-pixels in the non-bendable region. This changes the optical display effect, reduces the perceptual difference between the bendable and non-bendable regions, and thus reduces the crease appearance of the bendable region in the foldable display, improving the display effect of the foldable display and providing a better user experience. At the same time, by using the original encapsulation layer and touch layer in the foldable display as the optical functional layer, the thickness and cost of the foldable display can be reduced, thus providing a screen design that reduces the crease effect in the bendable region, which is beneficial for industrial production and application.

[0065] In some implementations, reference Figure 6 As shown, the optical functional layer may further include a third organic film 151, which is disposed on the side of the touch layer away from the light-emitting layer 12, and the refractive index of the third organic film 151 is greater than that of the second organic film 141.

[0066] In practical applications, the material of the third organic membrane 151 can be an acrylic resin.

[0067] Furthermore, a third organic membrane 151 can be fabricated using processes such as CVD.

[0068] It should be noted that the number of layers of the third organic membrane 151 can be adjusted according to requirements such as the light emission position. For example, the third organic membrane 151 may include at least one sub-membrane.

[0069] As an example, the third organic membrane 151 includes a submembrane. Figure 6 The illustration is based on the third organic membrane 151, which includes a submembrane.

[0070] As another example, in the case where the third organic film 151 includes multiple sub-films, the refractive index of the multiple sub-films increases sequentially along the light emission direction of the light-emitting layer 12.

[0071] The foldable display provided in this application embodiment has an organic film on the light source with progressively increasing refractive index. Based on the principle that the incident angle of light in a medium with a low refractive index is greater than the exit angle of light in a medium with a high refractive index, the light emission angle of at least some sub-pixels located in the bendable area on the light-emitting surface of the foldable display can be adjusted. That is, by changing the screen structure, the light emission path is altered, reducing the difference between the light emission angle of at least some sub-pixels in the bendable area and the light emission angle of sub-pixels in the non-bendable area. This changes the optical display effect, reduces the perceptual difference between the bendable and non-bendable areas, thereby reducing the crease appearance in the bendable area of ​​the foldable display and improving the display effect, resulting in a better user experience. Simultaneously, by using the original encapsulation layer and touch layer in the foldable display as optical functional layers, the thickness and cost of the foldable display can be reduced, thus providing a screen design that mitigates the crease effect in the bendable area, which is beneficial for industrial production and application.

[0072] In some implementations, reference Figure 4 As shown, the encapsulation layer 13 may also include a coupled photonic layer (CPL) 131, which is disposed between the light-emitting layer 12 and the first organic film 132.

[0073] In the light emitted by the sub-pixel, some rays with large incident angles are reflected back by the cathode and cannot escape. Therefore, a light extraction layer 131 can be added between the sub-pixel and the encapsulation layer 13 (i.e., the side of the sub-pixel whose cathode is away from the anode) to change the light path and reduce the amount of light confined within the sub-pixel. With the light extraction layer 131 covering the cathode emitting side, the number of surface plasmon polaritons near the cathode electrode is reduced, thus reducing energy dissipation near the cathode electrode and increasing the effective transmittance of the cathode electrode.

[0074] In practical applications, the material of the light extraction layer 131 can be an organic material such as aluminum 8-hydroxyquinoline; or, the material of the light extraction layer 131 can be an inorganic material such as titanium dioxide (TiO2), magnesium oxide (MgO), magnesium fluoride (MgF2), and silicon dioxide (SiO2); or, the material of the light extraction layer 131 can be other suitable materials that can extract light.

[0075] Furthermore, the light extraction layer 131 can be fabricated using a fine metal mask (FMM), which allows the light extraction layer 131 to form light extraction units that correspond one-to-one with each different sub-pixel in the light-emitting layer 12 after fabrication.

[0076] The foldable display screen provided in this application embodiment can change the path of light emitted by sub-pixels through the light extraction layer, thereby reducing the light confined within the sub-pixels and improving the display effect of the foldable display screen.

[0077] In some implementations, reference Figure 7 As shown, the foldable display screen may also include a lens layer 161, which is disposed on the side of the optical functional layer away from the light-emitting layer 12. The lens layer 161 includes a plurality of convex lenses arranged in an array, and the center of each convex lens coincides with the light-emitting point of the light emitted from the light-emitting surface of each sub-pixel from the optical functional layer.

[0078] In practical applications, a lens layer 161 is added to the bendable region F, which allows the direction of light deflection in the bendable region F relative to the light in the non-bendable region E to be determined through multiple convex lenses. Any two adjacent convex lenses can be connected, or there can be a certain distance between any two adjacent convex lenses; no specific limitation is made here.

[0079] thus, Figure 7 The optical functional layer in the bendable region F is schematically drawn and configured as a convex lens structure to converge the light emitted from the bendable region F.

[0080] It should be noted that, Figure 7 In the diagram, c1 is the light-emitting point of the light emitted from the optical functional layer of the red sub-pixel, c2 is the light-emitting point of the light emitted from the optical functional layer of the green sub-pixel, and c3 is the light-emitting point of the light emitted from the optical functional layer of the blue sub-pixel.

[0081] The foldable display screen provided in this application embodiment can achieve further precise adjustment of the light emission angle of the foldable display screen located in the bendable area through the lens layer. This can further reduce the perceptual difference between the bendable area and the non-bendable area, while also reducing the light emission difference at different positions in the bendable area. This significantly reduces the crease appearance of the bendable area of ​​the foldable display screen and greatly improves the display effect of the foldable display screen.

[0082] In some implementations, reference Figure 8 and Figure 9 As shown, there is a third distance between the light rays emitted from the optical functional layer exiting surface of the first sub-pixel and the light rays emitted from the optical functional layer exiting surface of the second sub-pixel, and there is a fourth distance between the light rays emitted from the optical functional layer exiting surface of the third sub-pixel and the light rays emitted from the optical functional layer exiting surface of the second sub-pixel. The third distance is greater than the first distance, and the fourth distance is greater than the second distance.

[0083] When a foldable display is folded inwards, the non-foldable area of ​​the foldable display is positioned relative to it. With repeated inward bending over a long period, wrinkles will appear in the inward bending area, leading to creases. This causes the light emitted from some sub-pixels in the bendable area to have its emission angle relative to the light emitted from sub-pixels in the non-foldable area, deflecting towards the center of the bendable area. In other words, the light emitted from some sub-pixels in the inward bending area converges towards the center of the bendable area after emission.

[0084] Furthermore, due to the wrinkles that appear after bending the foldable display in the bendable area, some sub-pixels in the bendable area may experience varying degrees of brightness reduction, resulting in color shift issues in the foldable display within the bendable area. To improve this problem, three parameters can be coupled and adjusted: the pixel opening position between the pixel boundaries in the bendable area, the thickness of the organic film, and the radius of the bendable area. This allows adjustment of the light-emitting position of some sub-pixels in the bendable area, making their light sensitivity similar to, and ideally identical to, the light-emitting position of the non-bendable area. It should be noted that the radius of the bendable area determines which area of ​​the foldable display needs to have its pixel opening position and the thickness of the organic film in which area of ​​the foldable display needs to be changed. Additionally, the bending radius also determines the size of the bendable area.

[0085] The following explanation uses the example of the first sub-pixel being red, the second sub-pixel being green, and the third sub-pixel being blue.

[0086] As an example, see reference Figure 8 As shown, the foldable display substrate may include two non-bending regions E (the one on the left is called the first non-bending region, and the one on the right is called the second non-bending region) and a bendable region F. The first non-bending region is connected to the second non-bending region through the bendable region F. The red sub-pixel is connected to the first non-bending region along a second direction ( Figure 8 The third spacing k3 in the ox direction is less than Figure 4 The first spacing k1 along the ox direction between the red sub-pixel and the first non-bending area; the fourth spacing k4 along the ox direction between the blue sub-pixel and the second non-bending area is less than... Figure 4 The second distance k2 between the blue sub-pixel and the second non-bending region along the ox direction. This alters the light path of the light emitted from the sub-pixel located in the bendable region, causing the light-emitting point to move towards the non-bending region E. Specifically, the third distance d3 between the light emitted from the optical functional layer exiting surface of the red sub-pixel located in the bendable region F and the light emitted from the optical functional layer exiting surface of the green sub-pixel located in the bendable region F is greater than d1, and the fourth distance d4 between the light emitted from the optical functional layer exiting surface of the blue sub-pixel located in the bendable region F and the light emitted from the optical functional layer exiting surface of the green sub-pixel located in the bendable region F is greater than d2.

[0087] The pixel defining layer includes multiple pixel defining portions, which can be determined by comparing the width of at least one pixel defining portion in the bendable region F with the shortest distance along the ox direction between it and the first non-bendable region along the ox direction. Figure 4 The size is reduced to shift the position of the red sub-pixel in the bendable region F to the left, causing its light-emitting position to shift to the left as well; simultaneously, this can be achieved by comparing the width of at least one pixel boundary portion in the bendable region F with the shortest distance along the ox direction between it and the second non-bendable region along the ox direction. Figure 4 By reducing the size of the blue sub-pixel in the bendable area F, the position of the blue sub-pixel is moved to the right, causing its light emission position to move to the right as well. Combined, this can effectively improve the problem of vertical light emission position offset in foldable displays.

[0088] Alternatively, the pixel defining layer includes multiple pixel defining portions, which can be achieved by comparing the width of at least one pixel defining portion in the first bending region along the ox direction. Figure 4 The size is reduced to shift the position of the red sub-pixel in the bendable region F to the left, thereby shifting its light-emitting position to the left; simultaneously, the width of at least one pixel boundary in the second bend region along the ox direction can also be reduced compared to... Figure 4 By reducing the size of the blue sub-pixel in the bendable area F, the position of the blue sub-pixel is moved to the right, causing its light emission position to move to the right as well. Combined, this can effectively improve the problem of vertical light emission position offset in foldable displays.

[0089] As another example, see Figure 9 As shown, the optical functional layer has a second thickness along a direction perpendicular to the foldable display substrate, and the second thickness is less than the first thickness.

[0090] In practical applications, the thickness of at least one film layer in the optical functional layer can be compared to... Figure 4 Thinning. Specifically, it can be done by... Figure 9 Compared to the thickness h12 of the light extraction layer 131 along the oz direction. Figure 4 The thickness h11 of the light extraction layer 131 along the oz direction is reduced, thus... Figure 9 The thickness h22 of the first organic film 132 along the oz direction is compared to Figure 4 The thickness h21 of the first organic film 132 along the oz direction decreases, thus... Figure 9 The thickness h32 of the second organic film 141 along the oz direction is compared to Figure 4 The thickness h31 of the second organic film 141 along the oz direction decreases, thus reducing the thickness of the second organic film 141. Figure 9 The thickness h42 of the third organic film 151 along the oz direction is compared to Figure 4The thickness h41 of the third organic film 151 along the oz direction decreases. As a result, the thickness of the optical functional layer decreases, which can change the light emission path of the sub-pixels located in the bendable region. The light emission point moves towards the non-bendable region E. That is, the fifth distance d5 between the light emitted from the light-emitting surface of the optical functional layer by the red sub-pixel located in the bendable region F and the light emitted from the light-emitting surface of the optical functional layer by the green sub-pixel located in the bendable region F is greater than d1, and the sixth distance d6 between the light emitted from the light-emitting surface of the optical functional layer by the blue sub-pixel located in the bendable region F and the light emitted from the light-emitting surface of the optical functional layer by the green sub-pixel located in the bendable region F is greater than d2.

[0091] Therefore, it can be set Figure 9 Compared to the thickness of the intermediate optical functional layer Figure 4 The angle of deflection of light emitted from the red sub-pixel into the optical functional layer is reduced, thereby improving the offset problem of light rays emitted from the optical functional layer.

[0092] The foldable display provided in this application embodiment can improve the vertical light emission position offset problem of the foldable display by changing the position of the pixel opening in the bendable area or the thickness of the optical functional layer, thereby making the light emission effect of the foldable display better and the performance of the foldable display better.

[0093] This application also provides a display device, including the foldable display screen described above.

[0094] The aforementioned display device can be a flexible display device (also known as a flexible screen), and this is not a limitation. The aforementioned display device can be an OLED display device. The aforementioned display device can be any product or component with display functionality, such as a television, digital camera, mobile phone, or tablet computer; the aforementioned display device can also be applied in fields such as identity recognition and medical devices, with products that have been promoted or have good promotion prospects including security identity authentication, smart door locks, and medical image acquisition. This display device has advantages such as high stability, high luminous efficiency, long lifespan, low voltage, good display effect, high contrast, good imaging quality, and high product quality.

[0095] It should be noted that the foldable display screen in this application embodiment can refer to the above embodiment, and will not be repeated here.

[0096] This section only introduces the content related to the invention point; other information can be obtained by referring to relevant technologies, and will not be explained in detail here.

[0097] The above are merely preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A foldable display screen, characterized in that, include: A foldable display substrate includes a driving layer and a light-emitting layer disposed on one side of the driving layer. The light-emitting layer includes a plurality of pixel units arranged in an array. Each pixel unit includes a first sub-pixel, a second sub-pixel, and a third sub-pixel. The second sub-pixel is located between the first sub-pixel and the third sub-pixel. The foldable display substrate has a bendable region and a non-bendable region adjacent to the bendable region. An optical functional layer is disposed on the light-emitting side of the light-emitting layer. The optical functional layer includes an encapsulation layer and a touch layer. The touch layer is disposed on the side of the encapsulation layer away from the light-emitting layer. The encapsulation layer includes a first organic film, and the touch layer includes a second organic film. The refractive index of the second organic film is greater than that of the first organic film. The optical functional layer is used to reduce the difference between the light emission angle of at least a portion of the sub-pixels in the bendable region from the light-emitting surface of the optical functional layer and the light emission angle of the sub-pixels in the non-bendable region from the light-emitting surface of the optical functional layer. There is a first distance and a second distance between the light rays emitted from the light-emitting surfaces of the first sub-pixel and the third sub-pixel, respectively, and the light rays emitted from the light-emitting surfaces of the second sub-pixel. There is a first spacing and a second spacing between the first sub-pixel and the adjacent non-bendable region, respectively, in a direction parallel to the light-emitting layer. The optical functional layer has a first thickness in a direction perpendicular to the light-emitting layer.

2. The foldable display screen according to claim 1, characterized in that, The optical functional layer further includes a third organic film, which is disposed on the side of the touch layer away from the light-emitting layer, and the refractive index of the third organic film is greater than that of the second organic film.

3. The foldable display screen according to claim 2, characterized in that, The third organic membrane includes at least one sub-membrane.

4. The foldable display screen according to claim 3, characterized in that, In the case where the third organic film comprises multiple sub-films, the refractive index of the multiple sub-films increases sequentially along the light emission direction of the light-emitting layer.

5. The foldable display screen according to any one of claims 1 to 4, characterized in that, The foldable display screen further includes a lens layer disposed on the side of the optical functional layer away from the light-emitting layer. The lens layer includes a plurality of convex lenses arranged in an array, and the center of each convex lens coincides with the light-emitting point of the light emitted from the light-emitting surface of each sub-pixel from the optical functional layer.

6. The foldable display screen according to claim 1, characterized in that, There is a third distance between the light emitted from the light-emitting surface of the first sub-pixel and the light emitted from the light-emitting surface of the second sub-pixel, and there is a fourth distance between the light emitted from the light-emitting surface of the third sub-pixel and the light emitted from the light-emitting surface of the second sub-pixel. The third distance is greater than the first distance, and the fourth distance is greater than the second distance.

7. The foldable display screen according to claim 6, characterized in that, The foldable display substrate includes a first non-bendable region, a bendable region, and a second non-bendable region. The first non-bendable region is connected to the bendable region and the second non-bendable region. A third spacing exists between the first sub-pixel and the first non-bendable region along a direction parallel to the light-emitting layer. A fourth spacing exists between the third sub-pixel and the second non-bendable region along a direction parallel to the light-emitting layer. The third spacing is smaller than the first spacing, and the fourth spacing is smaller than the second spacing.

8. The foldable display screen according to claim 6, characterized in that, The optical functional layer has a second thickness along a direction perpendicular to the light-emitting layer, and the second thickness is less than the first thickness.

9. The foldable display screen according to claim 6, characterized in that, The first sub-pixel is a red sub-pixel, the second sub-pixel is a green sub-pixel, and the third sub-pixel is a blue sub-pixel.

10. A foldable display device, characterized in that, Including the foldable display screen as described in any one of claims 1 to 9.

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