Display device

Abstract

The invention discloses a display device. The display device comprises a transparent substrate and a plurality of display units located on one side of the transparent substrate. The transparent substrate comprises a first light emitting surface far away from one side of the display unit; the display device further comprises a dimming layer, and the dimming layer is arranged on the side, away from the display unit, of the transparent substrate. The dimming layer is used for taking out light emitted from the display units to the first light-emitting face and reflecting light totally reflected on the face, away from the first light-emitting face, of the dimming layer towards the outside of the multiple display units. The problem of optical crosstalk can be solved, and the contrast ratio of the display device is improved.

Description

Technical Field

[0001] This invention relates to the field of display technology, and more particularly to a display device. Background Technology

[0002] Micro-LED (Micro Light Emitting Diode) has become the core direction of next-generation display technology due to its significant advantages such as self-illumination, high brightness, high response speed (microsecond level), long life (more than 100,000 hours) and low power consumption. It is widely used in high-end consumer electronics, professional displays, automotive displays, AR (Augmented Reality) and VR (Virtual Reality) fields.

[0003] However, with the increasing demand for display resolution, the pixel size of Micro-LEDs continues to shrink. Currently, the pixel pitch of mainstream products has dropped to below 5μm, and high-end AR devices have even reached the 1μm level, significantly reducing the physical distance between adjacent pixels. Because Micro-LED chips have a large emission angle and the emission areas of each chip in the pixel array lack efficient isolation, some light diffuses into adjacent pixel areas through the substrate, encapsulation layer, or air gaps, causing optical crosstalk. Optical crosstalk causes the light from adjacent pixels to overlap, resulting in increased brightness in dark conditions and blurred boundaries in bright conditions, thus reducing the contrast of the display device. Summary of the Invention

[0004] This invention provides a display device to improve the problem of optical crosstalk.

[0005] According to one aspect of the present invention, a display device is provided, the display device comprising a transparent substrate and a plurality of display units located on one side of the transparent substrate; the transparent substrate includes a first light-emitting surface on the side away from the display units; The display device further includes a dimming layer disposed on the side of the transparent substrate away from the display unit; the dimming layer is used to extract the light emitted from the display unit onto the first light-emitting surface, and to reflect the light that is totally reflected on the side away from the first light-emitting surface toward the outside of the plurality of display units.

[0006] Optionally, the dimming layer includes a window layer and an adhesive layer; The adhesive layer is used to bond the window layer and the transparent substrate; The thickness of the window layer satisfies the following relationship: Wherein, r1 is the emission angle of the preset light emitted from the display unit, the preset light is the light with the minimum emission angle that undergoes total internal reflection when incident from the light-emitting surface into the air, r2 is the emission angle of the preset light after it is incident on the transparent substrate, r3 is the emission angle of the preset light after it is incident on the adhesive layer, and r4 is the emission angle of the preset light after it is incident on the window layer; h0 is the thickness of the display unit, h1 is the thickness of the adhesive layer, d is the thickness of the transparent substrate, H is the thickness of the window layer, and L is the distance between the two display units with the largest distance.

[0007] Optionally, the refractive index range of the adhesive layer and the window layer is 0.9×n2 to 1.1×n2; where n2 is the refractive index of the transparent substrate.

[0008] Optionally, the display unit is disposed in contact with the transparent substrate, and the refractive index of both the adhesive layer and the window layer is greater than the refractive index of the transparent substrate.

[0009] Optionally, the display device further includes a connection layer disposed between the display unit and the transparent substrate; the refractive index of the connection layer is less than the refractive index of the transparent substrate; The refractive indices of the adhesive layer and the window layer are both greater than the refractive index of the connecting layer, and less than or equal to the refractive index of the transparent substrate.

[0010] Optionally, the difference between the thermal expansion coefficient of the window layer and the thermal expansion coefficient of the transparent substrate is within a first preset threshold. And / or, the glass transition temperature of the adhesive layer is greater than the application temperature of the display device.

[0011] Optionally, the side of the dimming layer away from the transparent substrate has a convex shape.

[0012] Optionally, the dimming layer includes an edge region surrounding the orthographic projection of the plurality of display units onto the dimming layer; the side of the dimming layer near the transparent substrate is located in the portion of the edge region, and / or the sidewalls of the dimming layer are coated with a light-absorbing material.

[0013] Optionally, an antireflective film is provided on the side of the dimming layer away from the transparent substrate, and the thickness of the antireflective film is: d1=λ / 4n; where d1 is the thickness of the antireflective film, λ is the target wavelength of the display device, and n is the refractive index of the antireflective film.

[0014] Optionally, the display device further includes an array substrate located on the side of the display unit away from the transparent substrate, the array substrate being used to drive the display unit.

[0015] The technical solution of this invention employs a display device including a transparent substrate and a plurality of display units located on one side of the transparent substrate. The transparent substrate includes a first light-emitting surface on the side away from the display units. The display device further includes a dimming layer disposed on the side of the transparent substrate away from the display units. The dimming layer is used to extract light emitted from the display units onto the first light-emitting surface and to reflect light that is totally reflected on the side away from the first light-emitting surface toward the outside of the plurality of display units. By providing a dimming layer, light that would be totally reflected onto the display units and form far-field crosstalk in related technologies is reflected to the outside of the display units, thereby solving the problem of far-field crosstalk and improving the contrast of the display device.

[0016] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A schematic diagram illustrating the principle of generating far-field crosstalk for display devices based on related technologies; Figure 2 This is a schematic diagram of the structure of a display device provided in an embodiment of the present invention; Figure 3 A top view of a display device provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of another display device provided in an embodiment of the present invention; Figure 5 This is a schematic diagram of the structure of another display device provided in an embodiment of the present invention; Figure 6 for Figure 2 Corresponding simulation result diagram; Figure 7 for Figure 5 Corresponding simulation result diagram; Figure 8 This is a schematic diagram of another display device provided in an embodiment of the present invention. Detailed Implementation

[0019] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0020] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0021] The display devices in related technologies suffer from severe optical crosstalk. Through extensive research, the inventors discovered that the cause of this problem lies in the fact that Micro-LED devices, from a fabrication perspective, can be divided into two main categories: mass transfer and monolithic integration. Mass transfer involves separating micron-sized LED chips from the growth substrate and then transferring millions of them onto the driver substrate at once using high-precision equipment. Monolithic integration can be further divided into two types: one where the substrate is removed after flip-chip bonding, and the other where the substrate is retained.

[0022] Optical crosstalk in Micro-LED displays is of two types: inter-pixel crosstalk and near-field crosstalk. Inter-pixel crosstalk occurs when a pixel is lit, causing the light emitted to illuminate several adjacent or nearby pixels. Near-field crosstalk exists in all types of Micro-LED displays. Related technologies focus on protecting against near-field crosstalk, such as placing barriers between pixels, using microlens arrays on the light-emitting side of the display, or employing thin-film arrays with gradient refractive indices. However, as the pixel pitch of Micro-LEDs becomes increasingly smaller, implementing these solutions to near-field crosstalk becomes increasingly difficult.

[0023] Another type of optical crosstalk originates from the substrate and is called far-field crosstalk, which exists in inherited Micro-LED display devices that do not have their substrate removed. For example... Figure 1 As shown, Figure 1 This is a schematic diagram illustrating the principle of generating far-field crosstalk in a display device of related technology. The display device includes a transparent substrate 11 and multiple display units 12 disposed on one side of the transparent substrate 11. The refractive indices of both the transparent substrate 11 and the display units 12 are greater than the refractive index of air. For example, the refractive index of the display unit 12 is 2.3, and the refractive index of the transparent substrate 11 is 1.77. Light emitted from the display unit 12, after being incident on the transparent substrate 11, travels a certain distance to the interface between the transparent substrate 11 and air. When the incident angle is large, the light will undergo total internal reflection. For example, if the preset light ray G1 is the light ray corresponding to the minimum incident angle that causes total internal reflection, the emission angle of the display unit 12 corresponding to this light ray is the first angle r1, and the incident angle corresponding to the interface between the transparent substrate 11 and air is the second angle r2. According to Fresnel's law, r2 = arcsin(1 / 1.77) = 34.4°. The first angle r1 is: r1 = arcsin(sin(r2) × 1.77 / 2.3) = 25.7°. That is, light emitted from display unit 12 with an angle greater than 25.7° will be reflected within the transparent substrate 11, forming a far-field crosstalk ring 12C. Assuming the thickness of display unit 12 is h and the thickness of transparent substrate 11 is d, the radius of the far-field crosstalk ring 12C is: R = 2 × d × tan(r2) + h × tan(r1); when h is 5 μm and d is 500 μm, R = 0.684 mm. When the pixel pitch is 24.3 μm, the emitted light from a certain display unit 12 will affect other display units 12 spaced R / Pitch = 28, forming far-field crosstalk. In other words, the display units 12 within the far-field crosstalk ring 12C are illuminated, leading to problems such as insufficient contrast in the display device.

[0024] To address the aforementioned technical problems, the present invention proposes the following solutions: Figure 2 This is a schematic diagram of the structure of a display device provided in an embodiment of the present invention, with reference to... Figure 2 The display device includes a transparent substrate 11 and a plurality of display units 12 located on one side of the transparent substrate 11; the transparent substrate 11 includes a first light-emitting surface 101 on the side away from the display units 12; the display device also includes a dimming layer 14, which is disposed on the side of the transparent substrate 11 away from the display units 12; the dimming layer 14 is used to extract the light emitted from the display units 12 onto the first light-emitting surface 101, and to reflect the light that is totally reflected on the side away from the first light-emitting surface 101 toward the plurality of display units 12.

[0025] Specifically, the display device in this embodiment is, for example, a Micro-LED display device. The transparent substrate 11 is the substrate required during the growth of the display unit 12. When the display device is used subsequently, one side of the transparent substrate 11 is the light-emitting side; therefore, the transparent substrate 11 has transparent properties and can be glass or sapphire, etc. The display unit 12 may include sequentially stacked n-type semiconductor layers, active layers, p-type semiconductor layers, and electrode layers, etc. These semiconductor layers can be grown sequentially using processes such as epitaxial growth. The semiconductor material in the display unit 12 can be GaN, InGaN, AlGaN, or other III-V group materials, etc.

[0026] In this embodiment, a dimming layer 14 is also provided on the first light-emitting surface 101 of the transparent substrate 11. The dimming layer 14 has two functions: first, it extracts the light incident from the transparent substrate 11 onto the first light-emitting surface 101, preventing it from being directly reflected back to the display unit 12 from the first light-emitting surface 101; in other words, the light emitted from the display unit 12, after incident on the first light-emitting surface 101, can all enter the dimming layer 14. It should be noted that although the greater the thickness of the transparent substrate 11, the smaller the degree of far-field crosstalk, and even the possibility of no far-field crosstalk, the thickness of the transparent substrate 11 is not too thick due to factors such as cost and manufacturing process. The second function of the transparent substrate 11 is that on the side away from the first light-emitting surface 101, which can be defined as the second light-emitting surface 102, a portion of the light incident from the first light-emitting surface 101 onto the interior of the dimming layer 14 is transmitted, and the portion that undergoes total internal reflection is reflected to the outside of the display unit 12. In other words, the light that is totally reflected back into the transparent substrate 11 by the second light-emitting surface 102 will not strike any one of the display units 12, but will instead strike outside the multiple display units 12. The intersection of this light with the plane containing the display units 12 is located outside the multiple display units 12. Since the totally reflected light will not strike any one of the display units 12, there will be no far-field crosstalk problem, thereby greatly improving the contrast of the display device and thus improving the display effect.

[0027] In addition, it should be noted that although some of the light that does not undergo total internal reflection on the second light-emitting surface 102 will still be reflected into the display device in addition to the transmitted part, the crosstalk caused by this part of the beam energy is small and can be ignored.

[0028] The technical solution of this embodiment employs a display device including a transparent substrate and multiple display units located on one side of the transparent substrate. The transparent substrate includes a first light-emitting surface on the side away from the display units. The display device also includes a dimming layer disposed on the side of the transparent substrate away from the display units. The dimming layer is used to extract light emitted from the display units onto the first light-emitting surface and to reflect light that is totally reflected on the side away from the first light-emitting surface away from the multiple display units. By providing a dimming layer, light that would be totally reflected onto the display units and form far-field crosstalk in related technologies is reflected to the outside of the display units, thereby solving the problem of far-field crosstalk and improving the contrast of the display device.

[0029] Optionally, continue to refer to Figure 2 The display device also includes an array substrate 13, which is located on the side of the display unit 12 away from the transparent substrate 11 and is used to drive the display unit 12.

[0030] Specifically, the array substrate 13 is provided with a plurality of pixel circuits, each of which can drive at least one display unit 12. The pixel circuits are, for example, digitally driven pixel circuits, analog-driven pixel circuits, or mixed-signal driven pixel circuits. The specific circuit structure and working principle of the pixel circuits are well known to those skilled in the art and will not be described in detail here.

[0031] Optionally, in some embodiments, the emission color of multiple display units 12 can be the same, for example, all of them can emit blue light. In subsequent practical applications, structures such as quantum dots and phosphors can be set on the display device to achieve color display. That is, green quantum dots are set at the display units that need to display green light, and red quantum dots are set at the display units that need to display red light. Of course, this embodiment is not limited to this.

[0032] Optionally, Figure 3 This is a top view of a display device provided in an embodiment of the present invention, with reference to... Figure 2 and Figure 3 The dimming layer 14 includes a window layer 142 and an adhesive layer 141; the adhesive layer 141 is used to bond the window layer 142 and the transparent substrate 11; the thickness of the window layer 142 satisfies the following relationship: Wherein, r1 is the emission angle of the preset light ray G1 emitted from the display unit, the preset light ray G1 is the light ray with the minimum emission angle that undergoes total internal reflection when it is incident on the air from the light-emitting surface, r2 is the emission angle of the preset light ray G1 after it is incident on the transparent substrate 11, r3 is the emission angle of the preset light ray G1 after it is incident on the adhesive layer 141, and r4 is the emission angle of the preset light ray G1 after it is incident on the window layer; h0 is the thickness of the display unit, h1 is the thickness of the adhesive layer 141, d is the thickness of the transparent substrate, H is the thickness of the window layer 142, and L is the distance between the two display units 12 with the largest distance.

[0033] Specifically, as mentioned above, once the thickness of the display unit 12, the refractive index of the display unit 12, and the refractive index of the transparent substrate 11 are known, the emission angle of the preset ray G1, i.e., r1, can be calculated according to Fresnel's law. In some embodiments, the thickness of the display unit 12 can be understood as the distance between the light-emitting layer of the display unit 12 and the surface near the first light-emitting surface 101; of course, to simplify the calculation, the total thickness of the display unit 12 can also be used directly for calculation. According to trigonometric relationships, the distance k1 between the incident point of the preset ray G1 on the transparent substrate 11 and the light-emitting center in the first direction X can be obtained as: k1 = h0 × tan(r1). According to Fresnel's law, the refraction angle of the preset ray G1 in the transparent substrate 11 can be obtained. This refraction angle is the same as the incident angle at the interface between the transparent substrate 11 and the adhesive layer 141, i.e., r2, so r2 = arcsin(n1 × sin(r1) / n2); where n1 is the refractive index of the display unit 12 and n2 is the refractive index of the transparent substrate 11. Since the thickness d of the transparent substrate 11 and r2 are known, the distance k2 between the exit point and the incident point of the preset ray G1 in the first direction X can be calculated using trigonometric relationships. The formula is: k2 = d × tan(r2). Similarly, the refraction angle r3 of the preset ray G1 in the adhesive layer 141 can be calculated using Fresnel's law, which is r3 = arcsin(n2 × sin(r2) / n3); where n3 is the refractive index of the adhesive layer 141. Since the thickness h1 of the adhesive layer 141 and r3 are known, the distance k3 between the exit point and the incident point of the preset ray G1 in the first direction X can be calculated using trigonometric relationships. The formula is: k3 = h1 × tan(r3). Similarly, according to Fresnel's law, the angle of refraction of the preset ray G1 in the window layer 142, i.e., r4, can be calculated, thus r4 = arcsin(n3 × sin(r3) / n4); where n4 is the refractive index of the window layer 142. The thickness H of the window layer 142 is unknown, and r3 is known. Based on trigonometric relationships, the distance k4 between the exit point and the incident point of the preset ray G1 in the first direction X can be calculated using the formula: k4 = H × tan(r4). According to the principle of light reversibility, the distance k5 between the incident point of the preset ray G1 reflected back to the interface between the display unit 12 and the transparent substrate 11 and the light-emitting center in the first direction X is k5 = k1 + 2 × k2 + 2 × k3 + 2 × k4. In other words, in a display device, as long as the distance between the two farthest display units 12 is less than k5, it can be guaranteed that light emitted from any display unit 12 at any angle will not be reflected back to any display unit 12 after total internal reflection. Therefore, the equation k5 > L can be solved simultaneously, and the range of values ​​for H can be obtained from this equation.

[0034] It should be noted that the second direction Y is the thickness direction of the display device, and the first direction X is perpendicular to the second direction Y.

[0035] It is understandable that when the overall outline of the multiple display units 12 in the display device is rectangular, L is the length of the diagonal of the rectangle; when the overall outline of the multiple display units 12 in the display device is circular, L is the diameter of the circle; of course, when the overall outline of the multiple display units 12 in the display device is other irregular shapes, L can be calculated according to the specific shape.

[0036] Optionally, in some embodiments, the adhesive layer 141 may be a solid material or a liquid material, and may be cured by means of thermosetting or ultraviolet curing.

[0037] Alternatively, in some embodiments, the material of the window layer 142 can be a high refractive index material with good light transmittance, such as sapphire, glass, or organic sheet.

[0038] Alternatively, in some embodiments, other methods can be used to fix the window layer 142 to the transparent substrate 11. For example, it can be fixed by heat pressing or by fixing it on the side. However, it should be noted that the window layer 142 and the transparent substrate 11 need to be tightly bonded. In this embodiment, no adhesive layer 141 is required, and the thickness of the window layer 142 satisfies the following relationship: .

[0039] Optionally, in some embodiments, the refractive index of the adhesive layer 141 and the window layer 142 is in the range of 0.9×n2 to 1.1×n2; where n2 is the refractive index of the transparent substrate 11.

[0040] Specifically, in this embodiment, the refractive index of the adhesive layer 141 and the refractive index of the transparent substrate 11 are relatively close, and their refractive indices match. This ensures that when the transparent substrate 11 directly interacts with air, light that would normally undergo total internal reflection at the air interface is guided into the adhesive layer 141 instead of being completely reflected back into the transparent substrate 11. Furthermore, the refractive index of the window layer 142 is also relatively close to that of the transparent substrate 11, and their refractive indices match. This ensures that light incident on the adhesive layer 141 can be guided into the window layer 142 without total internal reflection. In summary, in this embodiment, the refractive indices of both the adhesive layer 141 and the window layer 142 match the refractive index of the transparent substrate 11, achieving the effect of extracting light emitted from the display unit 12 onto the first light-emitting surface 101.

[0041] Alternatively, in some embodiments, if the thickness of the window layer 142 is constant, the refractive index range of the window layer 142 can also be calculated according to the formula relating the window layer 142 to L.

[0042] Optionally, in some embodiments, the difference between the coefficient of thermal expansion of the window layer 142 and the coefficient of thermal expansion of the transparent substrate 11 is within a first preset threshold.

[0043] Specifically, the first preset threshold is, for example, 10% of the thermal expansion coefficient of the transparent substrate 11. The display unit 12 is a Micro-LED chip, which generates significant heat during operation. If the thermal expansion coefficient of the window layer 142 differs significantly from that of the transparent substrate 11, the difference in thermal expansion between the window layer 142 and the transparent substrate 11 can cause the window layer 142 to detach from the transparent substrate 11 when the temperature difference is large during application. This embodiment ensures that the difference in thermal expansion coefficients between the window layer 142 and the transparent substrate 11 is small, preventing the window layer 142 from detaching from the transparent substrate 11 when the temperature difference is too large, thus ensuring the stability of the display device and improving its lifespan.

[0044] Alternatively, in some embodiments, the glass transition temperature of the adhesive layer 141 is greater than the application temperature of the display device.

[0045] Specifically, the application temperature of a display device can be understood as the maximum temperature of its application scenario. If the display device is mainly used in the personal consumer field, its application temperature will not exceed 60 degrees Celsius; while if the display device is mainly used in the industrial field, its application temperature may exceed 100 degrees Celsius. When there is a high temperature state in the application temperature, by setting the glass transition temperature Tg of the adhesive layer 141 to be higher than the application temperature, it can be ensured that the adhesive layer 141 will not enter a high elastic state at the application temperature, thereby ensuring that the window layer 142 will not shift and will not affect the crosstalk removal effect of the window layer 142.

[0046] Optionally, in some embodiments, the refractive index of the window layer 142 can be gradually varied, wherein the gradual variation occurs from the edge of the window layer 142 towards the center. The direction from the edge towards the center is not the thickness direction of the window layer 142, but rather a direction parallel to the thickness direction. That is, the refractive index of the window layer 142 is high at the edge and decreases towards the center. This arrangement ensures that when light is incident on the edge of the window layer 142, the outgoing light is closer to the center of the display device, thereby improving the front light emission rate of the display device.

[0047] Optionally, refer to Figure 2 In some embodiments, the display unit 12 is disposed in contact with the transparent substrate 11, and the refractive index of the adhesive layer 141 and the window layer 142 is greater than the refractive index of the transparent substrate 11.

[0048] Specifically, in this embodiment, after the display unit 12 is epitaxially formed on the transparent substrate 11, it is not necessary to temporarily peel off the transparent substrate 11. The connection between the display unit 12 and the transparent substrate 11 is tighter, and the arrangement of multiple display units 12 will not be misaligned due to peeling. In this embodiment, the refractive indices of the adhesive layer 141 and the window layer 142 are both greater than the refractive index of the transparent substrate 11. Therefore, when the light emitted from the display unit 12 enters the transparent substrate 11 and is incident on the interface between the transparent substrate 11 and the adhesive layer 141, it is incident from a less dense area to a denser area, and total internal reflection will not occur. That is, it can be guided into the dimming layer 14.

[0049] Optionally, in some embodiments, the refractive index of the window layer 142 may be greater than that of the adhesive layer 141, thereby ensuring that light in the adhesive layer 141 can be guided into the window layer 142 and will not undergo total internal reflection within the adhesive layer 141.

[0050] Optionally, Figure 4 This is a schematic diagram of the structure of another display device provided in an embodiment of the present invention, with reference to... Figure 4 The display device also includes a connection layer 15, which is disposed between the display unit 12 and the transparent substrate 11. The refractive index of the connection layer 15 is less than that of the transparent substrate 11. The refractive indices of the adhesive layer 141 and the window layer 142 are both greater than that of the connection layer 15 and less than or equal to that of the transparent substrate 11.

[0051] Specifically, because the transparent substrate 11 has a high refractive index, therefore... Figure 2In the illustrated embodiment, to ensure that light within the transparent substrate 11 can be guided into the dimming layer 14, the refractive index of the dimming layer 14 needs to be greater than that of the transparent substrate 11. This requires the dimming layer 14 to have a higher refractive index, but there are fewer types of dimming layers 14 with higher refractive indices available, and their cost is also higher. In this embodiment, by providing the connecting layer 15, the refractive index requirement for the dimming layer 14 can be reduced, thereby reducing the cost of the dimming layer 14. More specifically, after the display unit 12 is grown on the transparent substrate 11, the transparent substrate 11 and the display unit 12 can be peeled off first. Then, a connecting layer 15 can be provided between the transparent substrate 11 and the display unit 12, and the three can be bonded together to form a stacked structure of the transparent substrate 11, the connecting layer 15, and the display unit 12. The refractive index of the connecting layer 15 is less than that of the transparent substrate 11 but greater than that of air. Therefore, as long as the light emitted from the display unit 12 can enter the connecting layer 15 and then from the connecting layer 15 into the transparent substrate 11, it follows a path from less dense to denser light, allowing all of it to enter the transparent substrate 11. Furthermore, in this embodiment, the refractive indices of the adhesive layer 141 and the window layer 142 can be set to be less than that of the transparent substrate 11 but greater than that of the connecting layer 15. For light that can enter the connecting layer 15, although it passes through the high-refractive-index transparent substrate 11, the angle of incidence is smaller than that of the light emitted from the display unit when it enters the dimming layer 14. This can still be equivalently understood as a path from less dense to denser light, meaning all of it can enter the dimming layer 14.

[0052] Furthermore, since the refractive index of the connecting layer 15 is greater than that of air, the light emitted from the display unit 12 must eventually exit into the air. In other words, light that cannot enter the connecting layer 15 will also not be able to exit into the air. Therefore, setting the connecting layer 15 will not reduce the light output of the display device.

[0053] In summary, by setting the connecting layer 15, the dimming layer 14 can be made of a material with a lower refractive index, which has a wider range of options and is also cheaper.

[0054] For example, the bonding layer 15 may be an adhesive layer.

[0055] Optionally, in some embodiments, the refractive index of the connecting layer 15 is 1.6, and the refractive indices of the adhesive layer 141 and the window layer 142 are both 1.61.

[0056] Optionally, in some embodiments, the refractive indices of the window layer 142, the adhesive layer 141, and the transparent substrate 11 are all the same. Light incident on the transparent substrate 11 does not change its path when it reaches the adhesive layer 141 and the window layer 142; all light can enter the adhesive layer 141 and the window layer 142, resulting in high light extraction efficiency. Furthermore, calculating the thickness of the window layer 142 is easier in this case, which helps reduce the design complexity of the display device.

[0057] Optionally, Figure 5 This is a schematic diagram of the structure of another display device provided in an embodiment of the present invention, with reference to... Figure 5 The side of the dimming layer 14 away from the transparent substrate 11 has a convex shape.

[0058] Specifically, the side of the dimming layer 14 away from the transparent substrate 11, which is also the side of the window layer 142 away from the transparent substrate 11, can serve as the light-emitting surface of the entire display device. By setting this surface to a convex shape, the dimming layer 14 becomes a curved dimming layer. Compared to a planar type, the incident angle of light at the interface between the window layer 142 and the air becomes smaller, that is, the angle r4 becomes smaller, thereby allowing light that would otherwise undergo total internal reflection to enter the air, thus increasing the light extraction efficiency.

[0059] For example, Figure 6 for Figure 2 The corresponding simulation result diagram, Figure 7 for Figure 5 The corresponding simulation results are illustrated in the diagram. During the simulation, the energy of the incident light beam was set to 1mW, and the energy of the light emitted from and reflected from the window layer 142 was detected. Specifically, a first light intensity detector 21 was placed on the side of the window layer 142 furthest from the display unit, and a second light intensity detector 22 was placed on the side of the display unit furthest from the window layer 142. The simulation results show that by making the side of the dimming layer 14 furthest from the transparent substrate 11 convex, less light is reflected back to the display unit. Figure 6 In the process, the energy detected by the first light intensity detector 21 is 0.178 mW, and the energy of the light (i.e., the energy of the crosstalk light) detected by the second light intensity detector 22 is 0.0129 mW. Figure 7 In the middle, the energy detected by the first light intensity detector 21 is 0.24mW, and the brightness is compared to Figure 6 The result shows a 35% improvement; the energy of the light detected by the second light intensity detector 22 is 0.0089mW, and the crosstalk is compared to... Figure 6 The result was a 69% reduction.

[0060] Furthermore, setting the side of the dimming layer 14 away from the transparent substrate 11 to a convex shape not only increases light intensity and reduces crosstalk, but also allows for changes in the light emission angle, display area size, and pixel size of the display device. In this case, the dimming layer 14 acts like a convex lens, and its curved shape can be adjusted according to specific needs, thereby altering the imaging effect. In summary, the curved dimming layer offers greater flexibility to adapt to a wider range of applications.

[0061] It should be noted that when the dimming layer 14 is a curved dimming layer, its minimum thickness range is the same as the range of H mentioned above.

[0062] Optionally, Figure 8 This is a schematic diagram of the structure of another display device provided in an embodiment of the present invention, with reference to... Figure 8 The dimming layer 14 includes an edge region NAA surrounding the orthographic projection of a plurality of display units 12 onto the dimming layer 14; the side of the dimming layer 14 near the transparent substrate 11 is located in the portion of the edge region NAA, and / or the sidewalls of the dimming layer 14 are coated with a light-absorbing material 16.

[0063] Specifically, the size of the dimming layer 14 can be larger than the size of the transparent substrate 11. That is, the area of ​​the orthographic projection of the transparent substrate 11 onto the dimming layer 14 is smaller than the area of ​​the dimming layer 14, and is entirely located within the dimming layer 14. Furthermore, the display units 12 in the display device are all disposed within the display area AA. The edge region NAA of the dimming layer 14 surrounds the display area AA. A light-absorbing material 16 is disposed on the surface of the edge region NAA near the transparent substrate 11 and on at least one sidewall of the dimming layer 14. This material can absorb crosstalk light guided into the window layer 142, preventing crosstalk light from re-entering the display unit after multiple reflections at the edge of the window layer 142. In other words, by providing a light-absorbing material, crosstalk can be further reduced and contrast improved.

[0064] Optionally, in some embodiments, the light-absorbing material 16 is, for example, a black coating. When the portion of the dimming layer 14 located in the edge region NAA includes both an area overlapping with the transparent substrate 11 and an area not overlapping with the transparent substrate, the area not overlapping with the transparent substrate and the sidewalls can be blackened using a black pen after the dimming layer 14 is bonded to the transparent substrate 11. Alternatively, the portion of the dimming layer 14 on the surface away from the transparent substrate 11 corresponding to the display area AA can be temporarily protected with non-residue tape, and then the sidewalls of the dimming layer 14 and the portion not overlapping with the transparent substrate 11 can be sprayed to ensure that each area is uniformly blackened, and then the tape can be removed. For the portion of the edge region NAA that overlaps with the transparent substrate 11, it can be blackened using screen printing. Alternatively, in some embodiments, the entire portion of the dimming layer 14 on the surface near the transparent substrate 11 in the edge region NAA can be screen printed to form the aforementioned light-absorbing material 16. By screen printing, a very thin light-absorbing material 16 can be formed, which avoids the height difference on the surface of the dimming layer 14 after the light-absorbing material 16 is set, and thus avoids the problem of gaps between the transparent substrate 11 and the dimming layer 14 after the dimming layer 14 is bonded to the transparent substrate 11.

[0065] Optionally, in some embodiments, an antireflective film is further provided on the side of the dimming layer 14 away from the transparent substrate 11. The thickness of the antireflective film is d1 = λ / 4n; where d1 is the thickness of the antireflective film, λ is the target wavelength of the display device, and n is the refractive index of the antireflective film.

[0066] Specifically, the antireflective coating can suppress Fresnel reflection on the surface of window layer 142, thereby further improving contrast. The antireflective coating can be formed by coating or directly bonded to window layer 142.

[0067] For example, this invention utilizes a gallium nitride-based green Micro-LED display device on a sapphire substrate for testing. The display device is equipped with an anti-reflection film and light-absorbing material, and the window layer is planar. The test item is contrast ratio, with a display device of the same parameters without a window layer as the comparison. According to the ANSI contrast ratio test method, a 16-grid black-and-white checkerboard pattern is used to test both display devices. A PR655 luminance meter is used to measure the brightness values ​​of the white and black areas of the checkerboard pattern, and the average values ​​are taken. The ratio of the average brightness value in the bright area to the average brightness value in the dark area is used as the contrast ratio of the display device. Without the window layer, the average brightness value in the bright area is 139.46, the average brightness value in the dark area is 6.45, and the absolute contrast ratio is 21.62. After attaching the window layer, the average brightness value in the bright area is 137.83, the average brightness value in the dark area is 1.54, and the absolute contrast ratio is 89.45. It can be seen that attaching the window layer increases the contrast ratio by 4.1 times.

[0068] Based on the same inventive concept, the present invention also provides a light field display device, which includes the display device provided in any embodiment of the present invention. Since the light field display device provided in the embodiments of the present invention includes the display device provided in any embodiment of the present invention, it also has the same beneficial effects, and will not be described again here.

[0069] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0070] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A display device, characterized in that, The display device includes a transparent substrate and a plurality of display units located on one side of the transparent substrate; the transparent substrate includes a first light-emitting surface on the side away from the display units; The display device further includes a dimming layer disposed on the side of the transparent substrate away from the display unit; the dimming layer is used to extract the light emitted from the display unit onto the first light-emitting surface, and to reflect the light that is totally reflected on the side away from the first light-emitting surface toward the outside of the plurality of display units.

2. The display device according to claim 1, characterized in that, The dimming layer includes a window layer and an adhesive layer; The adhesive layer is used to bond the window layer and the transparent substrate; The thickness of the window layer satisfies the following relationship: Wherein, r1 is the emission angle of the preset light emitted from the display unit, the preset light is the light with the minimum emission angle that undergoes total internal reflection when incident from the light-emitting surface into the air, r2 is the emission angle of the preset light after it is incident on the transparent substrate, r3 is the emission angle of the preset light after it is incident on the adhesive layer, and r4 is the emission angle of the preset light after it is incident on the window layer; h0 is the thickness of the display unit, h1 is the thickness of the adhesive layer, d is the thickness of the transparent substrate, H is the thickness of the window layer, and L is the distance between the two display units with the largest distance.

3. The display device according to claim 2, characterized in that, The refractive index range of the adhesive layer and the window layer is 0.9×n2 to 1.1×n2; where n2 is the refractive index of the transparent substrate.

4. The display device according to claim 3, characterized in that, The display unit is disposed in contact with the transparent substrate, and the refractive index of the adhesive layer and the window layer is greater than the refractive index of the transparent substrate.

5. The display device according to claim 3, characterized in that, The display device further includes a connection layer disposed between the display unit and the transparent substrate; the refractive index of the connection layer is less than the refractive index of the transparent substrate. The refractive indices of the adhesive layer and the window layer are both greater than the refractive index of the connecting layer, and less than or equal to the refractive index of the transparent substrate.

6. The display device according to claim 2, characterized in that, The difference between the thermal expansion coefficient of the window layer and the thermal expansion coefficient of the transparent substrate is within a first preset threshold. And / or, the glass transition temperature of the adhesive layer is greater than the application temperature of the display device.

7. The display device according to claim 1, characterized in that, The side of the dimming layer away from the transparent substrate has a convex shape.

8. The display device according to claim 1, characterized in that, The dimming layer includes an edge region surrounding the orthographic projection of the plurality of display units onto the dimming layer; the side of the dimming layer near the transparent substrate is located in the portion of the edge region, and / or the sidewalls of the dimming layer are coated with a light-absorbing material.

9. The display device according to claim 1, characterized in that, An antireflective film is provided on the side of the dimming layer away from the transparent substrate. The thickness of the antireflective film is: d1=λ / 4n; where d1 is the thickness of the antireflective film, λ is the target wavelength of the display device, and n is the refractive index of the antireflective film.

10. The display device according to claim 1, characterized in that, The display device further includes an array substrate located on the side of the display unit away from the transparent substrate, and the array substrate is used to drive the display unit.

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