Display module, driving method thereof, and display device

Abstract

The present disclosure relates to the technical field of display, in particular to a display module, a driving method thereof and a display device. The display module comprises a display panel, an eyeball tracking sensor and a processor. The display panel comprises a substrate, a plurality of light emitting elements, an electrochromic layer, and an eyeball tracking sensor. The light emitting element comprises a first electrode, a second electrode, and a light emitting layer between the first electrode and the second electrode. The second electrode is located on the side of the light emitting layer away from the substrate. The first electrode is a full reflection electrode, and the second electrode is a semi-transparent and semi-reflective electrode. The electrochromic layer is located on the side of the second electrode away from the substrate. The vertical projection of the light emitting layer on the substrate is within the vertical projection of the electrochromic layer on the substrate. The eyeball tracking sensor is used to detect the current viewing angle direction of the user's eyeball in real time. The processor is used to adjust the refractive index of the electrochromic layer according to the current viewing angle direction. The present disclosure can improve the large viewing angle display effect while retaining the advantages of high luminous efficiency, high brightness and low power consumption at normal viewing angle.

Description

Technical Field

[0001] This disclosure relates to the field of display technology, and in particular to a display module and its driving method, and a display device. Background Technology

[0002] Organic light-emitting diode (OLED) display panels typically employ a top-emitting device structure to achieve high aperture ratio and high light extraction efficiency. In top-emitting OLEDs, an optical microcavity is formed between the anode (usually a total reflection electrode) and the cathode (a semi-transparent, semi-reflective electrode). This microcavity structure can resonate selectively with the photons generated by the emitting layer, altering the light field distribution at various angles, thereby significantly enhancing the light extraction intensity at the forward viewing angle and improving the color purity at specific wavelengths. However, the microcavity effect also introduces a significant viewing angle dependence problem.

[0003] At wide viewing angles, the interference optical path of light within the microcavity changes compared to the direct viewing angle, effectively narrowing the effective optical length of the microcavity and causing a deviation in the resonance condition. When a user views the display panel from a side viewpoint, the brightness attenuation curves with viewing angle are inconsistent due to differences in the position and optical characteristics of the emitting layers of each color sub-pixel within the microcavity. Simultaneously, the resonant wavelength of the microcavity undergoes a blue or red shift with the viewing angle, resulting in different color change patterns for different color sub-pixels. The combined effect of these brightness attenuation differences and color shifts causes a significant deviation in the color coordinates of the mixed white light from the direct viewing angle, resulting in a color shift at different viewing angles. This color shift is particularly pronounced at wide viewing angles, severely impacting the color fidelity of the displayed image and the viewing experience. Summary of the Invention

[0004] In order to solve the above-mentioned technical problems, or at least partially solve the above-mentioned technical problems, this disclosure provides a display module and its driving method and display device, which can improve the display effect at wide viewing angles while retaining the advantages of high luminous efficiency, high brightness and low power consumption at normal viewing angles.

[0005] In a first aspect, this disclosure provides a display module, including: a display panel, an eye-tracking sensor, and a processor, wherein the processor is electrically connected to the display panel and the eye-tracking sensor respectively; the display panel includes: a substrate; a plurality of light-emitting elements located on one side of the substrate, each light-emitting element including a first electrode, a second electrode, and a light-emitting layer located between the first electrode and the second electrode, the second electrode being located on the side of the light-emitting layer away from the substrate, the first electrode being a total internal reflection electrode, and the second electrode being a semi-transparent and semi-reflective electrode; an electrochromic layer located on the side of the second electrode away from the substrate, wherein the vertical projection of the light-emitting layer onto the substrate is located within the vertical projection of the electrochromic layer onto the substrate; the eye-tracking sensor is used to detect the current viewing angle direction of the user's eyeball in real time; and the processor is used to adjust the refractive index of the electrochromic layer according to the current viewing angle direction.

[0006] Secondly, this disclosure provides a driving method for a display module, applied to the display module provided in this disclosure; the driving method includes: real-time detection of the current viewing angle direction of the user's eyeball; and adjustment of the refractive index of the electrochromic layer according to the current viewing angle direction.

[0007] Thirdly, this disclosure also provides a display device including the aforementioned display module.

[0008] The technical solution provided in this disclosure has the following advantages compared with the prior art: In the display module provided in this disclosure, the display panel includes an electrochromic layer located on the side of the second electrode away from the substrate. The vertical projection of the light-emitting layer onto the substrate lies within the vertical projection of the electrochromic layer onto the substrate. That is, the electrochromic layer completely covers the light-emitting area in the horizontal direction. This ensures that light rays emitted from the light-emitting layer at all angles must pass through the electrochromic layer after leaving the microcavity. The display module also includes an eye-tracking sensor and a processor. The processor is electrically connected to both the eye-tracking sensor and the display panel. The eye-tracking sensor collects the user's gaze direction information in real time and calculates the angle between the current user's line of sight and the normal to the display panel, i.e., the current viewing angle, using an algorithm. After receiving this viewing angle data, the processor dynamically calculates the refractive index adjustment required to compensate for the microcavity optical path difference offset under this viewing angle, based on a built-in optical compensation algorithm, and then applies a corresponding driving voltage to the electrochromic layer. Under voltage drive, the electrochromic layer rapidly changes its molecular orientation or band state, causing its refractive index to change precisely to the target value, thereby achieving real-time adjustment of the optical path length of light rays passing through it. This disclosure achieves dynamic compensation for the optical path difference of light rays at wide viewing angles by adjusting the refractive index of the electrochromic layer. This keeps the optical length of the equivalent microcavity stable under different viewing angles, thus maintaining consistent resonance conditions and effectively suppressing the drift of the white light color coordinates with viewing angle, significantly improving the color fidelity of the displayed image at wide viewing angles. Furthermore, this disclosure does not alter the microcavity structure or light-emitting characteristics of the light-emitting element itself, nor does it block or absorb any emitted light. The compensation is achieved entirely by adjusting the refractive index of the electrochromic layer. Therefore, the high luminous efficiency, high brightness, and low power consumption advantages of the display panel at normal viewing angles are fully preserved, while the display effect at wide viewing angles is enhanced, achieving a balance between high efficiency and wide viewing angles. Attached Figure Description

[0009] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure.

[0010] To more clearly illustrate the technical solutions in the embodiments of this disclosure or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0011] Figure 1 This is a schematic diagram of the structure of a display module provided in this disclosure; Figure 2 yes Figure 1 A plan view of the display panel in the aforementioned display module; Figure 3 yes Figure 2 A cross-sectional view of the display panel along line A-A'; Figure 4 yes Figure 2 The diagram shows a light source of the display panel. Figure 5 yes Figure 2 Another cross-sectional view of the display panel along A-A'; Figure 6 yes Figure 2 Another cross-sectional view of the display panel along A-A'; Figure 7 yes Figure 2 A cross-sectional view of the display panel along B-B'; Figure 8 This is a flowchart of a driving method for a display module provided in this disclosure; Figure 9 This is a plan view of a display device provided in this disclosure. Detailed Implementation

[0012] To better understand the above-mentioned objectives, features, and advantages of this disclosure, the solutions disclosed herein will be further described below. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other.

[0013] Numerous specific details are set forth in the following description in order to provide a full understanding of this disclosure, but this disclosure may also be implemented in other ways different from those described herein; obviously, the embodiments in the specification are only some, and not all, of the embodiments of this disclosure.

[0014] Figure 1 This is a schematic diagram of the structure of a display module provided in this disclosure. Figure 2 yes Figure 1 A plan view of the display panel in the aforementioned display module. Figure 3 yes Figure 2A cross-sectional view of the display panel along A-A', see reference. Figures 1-3 This disclosure provides a display module, which includes a display panel 100, an eye-tracking sensor 200, and a processor 300, wherein the processor 300 is electrically connected to the display panel 100 and the eye-tracking sensor 200 respectively. The display panel 100 includes: Substrate 110; Multiple light-emitting elements 120 are located on one side of the substrate 110. Each light-emitting element 120 includes a first electrode 121, a second electrode 122, and a light-emitting layer 123 located between the first electrode 121 and the second electrode 122. The second electrode 122 is located on the side of the light-emitting layer 123 away from the substrate 110. The first electrode 121 is a total reflection electrode, and the second electrode 122 is a semi-transparent and semi-reflective electrode. The electrochromic layer 130 is located on the side of the second electrode 122 away from the substrate 110, and the vertical projection of the light-emitting layer 123 onto the substrate 110 is located within the vertical projection of the electrochromic layer 130 onto the substrate 110. The eye-tracking sensor 200 is used to detect the current viewing direction of the user's eyes in real time; The processor 300 is used to adjust the refractive index of the electrochromic layer 130 according to the current viewing direction.

[0015] Specifically, this embodiment provides a display module, which includes a display panel 100. The display panel 100 includes a substrate 110 and a plurality of light-emitting elements 120 arranged in an array on one side of the substrate 110. The light-emitting elements 120 are top-emitting OLED devices, and each light-emitting element 120 includes a first electrode 121, a second electrode 122, and a light-emitting layer 123 located between the first electrode 121 and the second electrode 122. The second electrode 122 is located on the side of the light-emitting layer 123 away from the substrate 110. The first electrode 121 is a total internal reflection electrode, and the second electrode 122 is a semi-transparent and semi-reflective electrode. A Fabry-Perot optical microcavity is formed between the first electrode 121 and the second electrode 122. Photons generated by the light-emitting layer 123 are reflected back and forth within the microcavity and interfere. Light of a specific wavelength is resonantly enhanced and then efficiently emitted from the direction away from the substrate 110 from the second electrode 122, thereby significantly improving the forward brightness.

[0016] Figure 4 yes Figure 2 The diagram shown illustrates a type of light pattern on a display panel. (Reference) Figure 4 Photons generated by the light-emitting layer 123 are reflected back and forth and interfere within the microcavity formed between the first electrode 121 and the second electrode 122. Light of wavelength that satisfies the resonance condition is coherently enhanced within the microcavity and is emitted from the side of the second electrode 122 away from the substrate 110, forming outgoing light rays.

[0017] In this diagram, ray L1 represents the light emitted from the frontal viewing direction (i.e., perpendicular to the surface of the display panel), and ray L2 represents the light emitted from the lateral viewing direction (i.e., at a certain angle θ to the normal direction of the display panel). For the frontal viewing ray L1, it is emitted along the normal direction of the display panel, and its round-trip propagation path within the microcavity is perpendicular to the microcavity. Its effective optical path is the product of the physical thickness of the microcavity and the refractive index of each layer of the medium. For the lateral viewing ray L2, because the light propagates at an inclined angle and is reflected within the microcavity, its actual geometric path for round-trip propagation within the microcavity is longer than that of the frontal viewing ray L1. However, it is important to note that the effective optical path of microcavity interference depends not only on the geometric path length but also on the phase jump generated at the reflection interface. Under large viewing angles, the reflection phase of the light at the second electrode 122 (semi-transparent and semi-reflective electrode) changes significantly with increasing incident angle, causing the total phase change accumulated between the two reflections of ray L2 to change relative to the frontal viewing ray L1. Considering the combined effects of geometric path changes and reflection phase changes, the effective interference optical path of the lateral viewing angle ray L2 is significantly shorter than that of the frontal viewing angle ray L1, meaning the equivalent microcavity's optical length is narrower at large viewing angles. A stronger microcavity effect results in more significant resonance enhancement at the frontal viewing angle, leading to higher luminous brightness and color purity. However, this also increases the microcavity's directivity, causing more severe brightness attenuation and color shift at large viewing angles, and narrowing the effective viewing angle range of the display panel. If the microcavity effect is weakened to widen the viewing angle, it must come at the cost of sacrificing brightness at the frontal viewing angle and increasing device power consumption.

[0018] Based on this, the display panel 100 also includes an electrochromic layer 130, which is located on the side of the second electrode 122 away from the substrate 110. The electrochromic layer 130 is made of a material whose refractive index can change with the applied voltage. The vertical projection of the light-emitting layer 123 onto the substrate 110 lies within the vertical projection of the electrochromic layer 130 onto the substrate 110. That is, the electrochromic layer 130 completely covers the light-emitting area in the horizontal direction. This ensures that light rays at all angles emitted from the light-emitting layer 123 (including frontal and lateral wide-angle light rays) must pass through the electrochromic layer 130 after leaving the microcavity. The display module also includes an eye-tracking sensor 200 and a processor 300. The processor 300 is electrically connected to both the eye-tracking sensor 200 and the display panel 100. The processor 300 can be directly electrically connected to the electrochromic layer 130. The eye-tracking sensor 200 collects the user's gaze direction information in real time and calculates the angle between the current user's line of sight and the normal of the display panel 100, i.e., the current viewing angle direction, through an algorithm. After receiving this viewing angle data, the processor 300 dynamically calculates the amount of refractive index adjustment required to compensate for the microcavity optical path difference shift at this viewing angle based on a built-in optical compensation algorithm, and then applies a corresponding driving voltage to the electrochromic layer 130. Under voltage driving, the electrochromic layer 130 rapidly changes its molecular orientation or band state, causing its refractive index to change precisely to the target value, thereby achieving real-time adjustment of the optical path length of light passing through it. In other words, this disclosure dynamically compensates for the optical path difference of light at large viewing angles by adjusting the refractive index of the electrochromic layer 130, keeping the optical length of the equivalent microcavity stable at different viewing angles, thus maintaining consistent resonance conditions, effectively suppressing the drift of white light color coordinates with viewing angle, and significantly improving the color fidelity of the display image at large viewing angles.

[0019] Furthermore, this disclosure does not alter the microcavity structure and light-emitting characteristics of the light-emitting element 120 itself, nor does it block or absorb any emitted light. The compensation is achieved entirely by adjusting the refractive index of the electrochromic layer 130. Therefore, the display panel 100 retains its advantages of high luminous efficiency, high brightness, and low power consumption at a normal viewing angle, while simultaneously enhancing the wide viewing angle display effect, achieving a balance between high efficiency and wide viewing angle.

[0020] Continue to refer to Figures 1-3 In some alternative embodiments, the electrochromic layer 130 is made of liquid crystal or semiconductor material.

[0021] Specifically, the electrochromic layer 130 can be made of liquid crystal. Liquid crystal materials have birefringence properties, with ordinary refractive index n0 and extraordinary refractive index n0. e There are differences. When different voltages are applied to both sides of the electrochromic layer 130, the liquid crystal molecules undergo orientation shift under the drive of the electric field, causing the equivalent refractive index of the liquid crystal layer to the transmitted light to differ between n0 and n... eThe equivalent refractive index can be continuously adjusted by precisely controlling the magnitude of the driving voltage.

[0022] The electrochromic layer 130 can be made of a semiconductor material. When a voltage is applied to the semiconductor electrochromic layer, charge carriers (electrons or holes) are injected into the semiconductor material, causing a change in the concentration of free charge carriers in the material. According to plasma oscillation theory, the change in the concentration of free charge carriers alters the dielectric constant of the material, thereby causing a change in the refractive index. For example, the electrochromic layer 130 can be made of an electro-optic material, such as lithium niobate, lithium tantalate, potassium dideuterium phosphate, gallium arsenide, etc., or it can be a phase change material, such as a germanium-antimony-tellurium alloy, etc.

[0023] Figure 5 yes Figure 2 Another cross-sectional view of the display panel along A-A', see reference. Figure 1 , Figure 2 and Figure 5 In some alternative embodiments, the display panel 100 further includes a third electrode 140, which is located on the side of the second electrode 122 away from the substrate 110, and the third electrode 140 is a semi-transparent and semi-reflective electrode. The electrochromic layer 130 is located between the second electrode 122 and the third electrode 140.

[0024] Specifically, the display panel 100 also includes a third electrode 140, which is a semi-transparent and semi-reflective electrode, meaning it partially transmits and partially reflects visible light. The third electrode 140 can be made of the same material as the second electrode 122, or it can be made of a different material. The third electrode 140 is located on the side of the second electrode 122 away from the substrate 110, and the electrochromic layer 130 is located between the second electrode 122 and the third electrode 140. Because the third electrode 140 is a semi-transparent and semi-reflective electrode, light modulated by the electrochromic layer 130 can partially pass through the third electrode 140 and be emitted outwards, thus entering the human eye and enabling normal viewing of the displayed image. Simultaneously, the third electrode 140 can reflect some of the light, which is reflected back towards the electrochromic layer 130 and the light-emitting element 120. Under appropriate phase conditions, this reflected light can further participate in microcavity resonance or assist in optical path compensation. In addition, the third electrode 140 can also provide physical protection for the electrochromic layer 130, preventing the electrochromic layer 130 from being damaged during subsequent processes or use.

[0025] Optionally, when driving electrodes are provided on both sides of the electrochromic layer 130 to provide an electric field to adjust the electrochromic layer 130, the second electrode 122 and the third electrode 140 can be reused as driving electrodes of the electrochromic layer 130.

[0026] Figure 6 yes Figure 2 Another cross-sectional view of the display panel along A-A', see reference. Figure 1 , Figure 2 and Figure 6 In some alternative embodiments, the display panel 100 further includes an encapsulation layer 150, which is located on the side of the light-emitting element 120 away from the substrate 110. The encapsulation layer 150 includes a first inorganic encapsulation layer 151 and a second inorganic encapsulation layer 152. The electrochromic layer 130 is located between the first inorganic encapsulation layer 151 and the second inorganic encapsulation layer 152.

[0027] Specifically, the display panel 100 also includes an encapsulation layer 150, which is located on the side of the light-emitting element 120 away from the substrate 110. The encapsulation layer 150 is used for thin-film encapsulation (TFE) of the light-emitting element 120 to prevent external moisture and oxygen from penetrating the interior of the light-emitting element 120 and extend the device's lifespan. The encapsulation layer 150 includes a first inorganic encapsulation layer 151 and a second inorganic encapsulation layer 152. An electrochromic layer 130 is located between the first inorganic encapsulation layer 151 and the second inorganic encapsulation layer 152.

[0028] The encapsulation layer 150 employs a multilayer thin-film stacked structure, comprising at least two inorganic insulating films: a first inorganic encapsulation layer 151 and a second inorganic encapsulation layer 152. The inorganic encapsulation layers are typically made of silicon nitride (SiN). x ), silicon dioxide (SiO) x Materials with excellent water and oxygen barrier properties, such as silicon oxynitride (SiON) and aluminum oxide (Al2O3), are prepared by chemical vapor deposition (CVD), atomic layer deposition (ALD), or physical vapor deposition (PVD). The inorganic encapsulation layer has high density and low pinhole density, which can effectively block the penetration of water vapor and oxygen, providing reliable environmental protection for the underlying light-emitting element 120.

[0029] It should be noted that the encapsulation layer 150 may further include an organic encapsulation layer (not shown in the figure) located between the first inorganic encapsulation layer 151 and the second inorganic encapsulation layer 152. The organic encapsulation layer is typically made of organic materials such as acrylic resin, epoxy resin, or polyimide, formed by inkjet printing or coating processes. Its function is to cover particle defects on the surface of the inorganic encapsulation layer, release film stress, and planarize the surface, thereby providing a smooth substrate for the deposition of the second inorganic encapsulation layer 152. When the encapsulation layer 150 includes an organic encapsulation layer, the electrochromic layer 130 can be disposed at the location of the organic encapsulation layer, i.e., the electrochromic layer 130 can replace or serve as the organic encapsulation layer, or an additional electrochromic layer 130 can be added between the organic encapsulation layer and the second inorganic encapsulation layer 152.

[0030] The electrochromic layer 130 is located between the first inorganic encapsulation layer 151 and the second inorganic encapsulation layer 152. That is, the electrochromic layer 130 is completely encapsulated between the first inorganic encapsulation layer 151 and the second inorganic encapsulation layer 152, and is both physically protected by the two inorganic encapsulation layers, and also avoids the corrosion of the electrochromic layer 130 material by external water and oxygen due to the excellent barrier properties of the inorganic encapsulation layers.

[0031] Optionally, when driving electrodes are provided on both sides of the electrochromic layer 130 to provide an electric field for adjusting the electrochromic layer 130, this can be achieved in various ways. In one feasible implementation, the first inorganic encapsulation layer 151 and the second inorganic encapsulation layer 152 themselves have certain conductivity or surface charge characteristics and can be used directly or indirectly as driving electrodes. In another implementation, conductive thin film layers (such as transparent conductive oxides ITO, IZO, or thin metal layers) can be provided between the first inorganic encapsulation layer 151 and the electrochromic layer 130, and between the electrochromic layer 130 and the second inorganic encapsulation layer 152, respectively, as independent driving electrode pairs.

[0032] Continue to refer to Figures 1-3 In some alternative embodiments, the processor 300 is used to calculate the compensated optical path difference based on the current viewing direction and adjust the refractive index of the electrochromic layer 130 based on the compensated optical path difference.

[0033] Specifically, in the display panel 100, the light emitted by the light-emitting layer 123 is reflected and interfered with within the Fabry-Perot optical microcavity formed between the first electrode 121 (total internal reflection electrode) and the second electrode 122 (semi-transparent and semi-reflective electrode). The resonance condition of the microcavity is determined by the optical path difference, which is the total optical path length traversed by the light in one round trip within the microcavity, including the product of the geometric path and the refractive index of each film layer, as well as the additional optical path corresponding to the phase jump that occurs at the two reflective interfaces.

[0034] When a user views the display panel 100 from a normal angle (i.e., the line of sight is perpendicular to the surface of the display panel 100), the light emitted from the light-emitting element 120 is emitted along the vertical direction of the microcavity. At this time, the microcavity has a defined effective optical path difference D0, and the corresponding resonant wavelength λ0 satisfies the enhanced interference condition. When the user views the display panel 100 from a side angle (i.e., the angle between the line of sight and the normal direction of the display panel 100 is θ), the light propagates at an angle within the microcavity. The reflection phase of the light at the second electrode 122 changes, and the geometric path of the oblique propagation is also different from that of the vertical propagation. These two factors cause the effective optical path difference of the microcavity to change from D0 to Dθ. This change in the effective optical path difference causes the resonant wavelength to shift to λθ, and different color sub-pixels exhibit inconsistent offsets and brightness attenuation patterns due to the different positions of the light-emitting layer 123 within the microcavity, thus causing viewing angle color shift.

[0035] The processor 300 can accurately calculate the optical path difference compensation based on the current viewing angle and translate it into fine adjustment of the refractive index of the electrochromic layer 130, so that the effective optical path of the microcavity at a wide viewing angle is actively restored to a level comparable to the normal viewing angle. As a result, the resonant wavelength at different viewing angles remains stable, the emitted spectrum of each color sub-pixel does not shift significantly with the viewing angle, and the color coordinates of the mixed white light remain consistent at different viewing angles, fundamentally eliminating viewing angle distortion and achieving color fidelity display across the entire viewing angle range.

[0036] Continue to refer to Figures 1-4 In some alternative embodiments, the processor 300 is used to calculate the compensation optical path difference according to the following formula: ; in, To compensate for the optical path difference, The optical path difference of the light rays from the light-emitting element 120 at a positive viewing angle. It is the angle between the current viewing direction and the forward viewing direction.

[0037] Specifically, in the display panel 100, the microcavity structure of the light-emitting element 120 is composed of a first electrode 121 (total internal reflection electrode) and a second electrode 122 (semi-transparent and semi-reflective electrode). When a user views the light at a normal viewing angle (θ=0°, i.e., the line of sight is perpendicular to the surface of the display panel 100), the light generated by the light-emitting layer 123 is emitted along the direction perpendicular to the microcavity, and the effective optical path difference experienced by the light traveling back and forth once within the microcavity is D0. This D0 value is determined by the physical thickness of the microcavity, the refractive index of each film layer, and the phase transition of light at the two reflective interfaces, and is an intrinsic parameter related to the specific structure of the light-emitting element 120.

[0038] When a user views the microcavity from a side angle (θ>0°), the light rays exit at an angle. Under large viewing angles, the reflection phase of the light rays at the second electrode 122 (a semi-transparent, semi-reflective electrode) changes with increasing incident angle, and the geometric path of the oblique propagation also differs from that of perpendicular propagation. The combined effect of these two factors alters the effective optical path difference of the microcavity from the side angle relative to the normal viewing angle. Based on the principles of optical interference and the Fabry-Perot microcavity theory, the effective optical path difference Dθ from the side angle and the optical path difference D0 from the normal viewing angle have the following relationship: .

[0039] The physical meaning of this relationship is that when light rays emerge at an angle θ, the effective optical length of the microcavity in the direction of light propagation is reduced to a factor of cosθ in the vertical direction, meaning the equivalent microcavity narrows at large viewing angles. Therefore, the change in effective optical path difference ΔD caused by the viewing angle shift is equal to the optical path difference D0 at the normal viewing angle and the effective optical path difference at the lateral viewing angle. Difference: .

[0040] As can be seen from the above formula, when θ=0 (positive viewing angle), cosθ=1, ΔD=0, meaning no optical path compensation is needed. This aligns with the optimal display effect and lack of color shift at the positive viewing angle. As θ increases from 0° to 90°, cosθ decreases from 1 to 0, while ΔD increases from 0 to D0. This means the compensation for the optical path difference increases monotonically with the viewing angle, and the compensation requirement rises as the degree of viewing angle shift intensifies. This monotonically increasing relationship conforms to the physical law that the larger the viewing angle, the more severe the color shift, and the stronger the required compensation.

[0041] After calculating the compensated optical path difference ΔD, the processor 300 uses it as an intermediate variable for subsequent refractive index adjustment of the electrochromic layer 130. Specifically, the processor 300 determines the magnitude of the driving voltage to be applied to the electrochromic layer 130 based on the value of ΔD, causing a corresponding change in the refractive index of the electrochromic layer 130. This change in refractive index increases the optical path length of light rays from a side viewing angle as they pass through the electrochromic layer 130 by ΔD, thereby compensating the effective optical path difference of the microcavity from D0×cosθ back to D0, restoring the resonance condition to the positive viewing angle state.

[0042] Optionally, during actual control, the processor 300 performs the above calculations and adjustments in real time, frame by frame. When each frame is displayed, the processor 300 reads the latest viewing direction data θ provided by the eye-tracking sensor 200, substitutes it into the formula to calculate ΔD, and then outputs a corresponding driving voltage based on ΔD to adjust the refractive index of the electrochromic layer 130. The entire calculation and adjustment process is completed within the frame scan cycle, ensuring the real-time nature and synchronization of the compensation.

[0043] Optionally, the optical path difference D0 of the light-emitting element 120 at a normal viewing angle is a key parameter in this formula. In practical applications of display modules, the display panel 100 typically includes red, green, and blue sub-pixels. The light-emitting layers 123 of the different colored sub-pixels are located in different positions within the microcavity, resulting in differences in their respective D0 values. For example, the light-emitting layer of the red sub-pixel is typically located in a position with a larger optical thickness within the microcavity to satisfy long-wavelength resonance conditions, while the light-emitting layer of the blue sub-pixel is located in a position with a smaller optical thickness.

[0044] Therefore, the D0 parameters stored in the processor 300 can be set separately for sub-pixels of different colors. Specifically, the processor 300's storage unit pre-stores the optical path difference D0_R for red sub-pixels, the optical path difference D0_G for green sub-pixels, and the optical path difference D0_B for blue sub-pixels. When calculating the compensation optical path difference, the processor 300 reads the corresponding D0 value according to the currently driven sub-pixel color and calculates the required compensation optical path difference for each color sub-pixel, thereby achieving fine-grained color separation compensation. The D0 value can be obtained through optical simulation calculation of the light-emitting element 120, or it can be calibrated through experimental testing, and the calibration result is written into the processor 300's storage unit.

[0045] Continue to refer to Figures 1-4 In some alternative embodiments, the processor 300 is used to adjust the refractive index of the electrochromic layer 130 according to the following formula: ; in, The refractive index of the electrochromic layer 130 after adjustment. is the initial refractive index of the electrochromic layer 130.

[0046] Specifically, in the display panel 100, the optical path length of light passing through the electrochromic layer 130 is equal to the product of the refractive index of the electrochromic layer 130 and the geometric path length of the light propagating within it. To restore the total optical path length of light at lateral viewing angles to a level comparable to that at the frontal viewing angle, an additional optical path increment needs to be introduced into the electrochromic layer 130, which is equal to the compensation optical path difference ΔD. Given a fixed physical thickness d of the electrochromic layer 130, the relationship between the optical path increment ΔD and the refractive index change Δn is: ΔD = Δn × d, where d is the geometric path length of light propagating in the electrochromic layer 130, which, under vertical emission conditions, is the film thickness of the electrochromic layer 130.

[0047] Considering that the optical thickness design of the electrochromic layer 130 in this embodiment is generally related to its initial refractive index n0, and that to achieve a large refractive index adjustment range, the film thickness d of the electrochromic layer 130 satisfies the approximate relationship d ≈ 1 / n0. Therefore, the refractive index adjustment amount Δn' = ΔD / n0. Adding the initial refractive index n0 of the electrochromic layer 130 to this adjustment amount yields the adjusted target refractive index: .

[0048] The initial refractive index n0 of the electrochromic layer 130 refers to the effective refractive index of the electrochromic layer 130 in the visible light band when no driving voltage is applied (or an initial bias voltage is applied). The value of n0 depends on the specific material and processing conditions used in the electrochromic layer 130.

[0049] At the same time, in the formula This section represents the permissible error tolerance. This tolerance setting provides the system with a ±10% refractive index adjustment range, meaning the actual value of Δn can be between n0 + ΔD / n0 - n0×0.1 and n0 + ΔD / n0 + n0×0.1.

[0050] This formula directly transforms the abstract compensation optical path difference ΔD into the refractive index change of the electrochromic layer 130, establishing a clear physical correspondence between optical path compensation and refractive index adjustment. This clear physical correspondence facilitates theoretical modeling, parameter design, and effect verification of the system, providing a solid theoretical foundation for the engineering implementation of the viewing angle compensation scheme. Furthermore, in the formula... The error tolerance term provides a ±10% fluctuation range for refractive index adjustment. This tolerance setting ensures that most of the optical path difference compensation is effectively achieved, guaranteeing that the improvement in visual angle deviation is clearly perceptible to the human eye. It also avoids control instability caused by factors such as material response deviations, environmental temperature changes, and limitations in the precision of the drive circuit. The introduction of this tolerance relaxes the precision requirements for various components and process steps, which is beneficial for improving mass production yield and product consistency.

[0051] Optionally, the processor 300 follows the specific procedure when performing refractive index adjustment: First, the processor 300 reads the pre-stored value of n0 from the storage unit and obtains the compensated optical path difference ΔD from the aforementioned calculation steps. Second, it substitutes n0 and ΔD into the formula Δn = n0 + ΔD / n0 to calculate the theoretical target refractive index. Third, based on preset control precision and error tolerance, it determines the acceptable range of the target refractive index (i.e., n0 + ΔD / n0 ± n0 × 0.1), and selects a specific target value within this range. This selection process can be based on pre-calibrated electrochromic layer refractive index and driving voltage response curves to select the target value that best matches the actual driving capability. Finally, based on the selected target refractive index, the processor 300 queries the correspondence between the refractive index and driving voltage of the electrochromic layer 130 (which can be stored in the form of a lookup table or fitting function), outputs the corresponding driving voltage to the electrochromic layer 130, so that the actual refractive index of the electrochromic layer 130 reaches the target value Δn.

[0052] The entire adjustment process is repeated within each frame display cycle to ensure that the refractive index remains synchronized with the current viewing direction. When the viewing direction θ changes, ΔD changes accordingly, and Δn is updated accordingly, achieving dynamic tracking compensation.

[0053] Continue to refer to Figures 1-3In some alternative embodiments, the processor 300 is also used to adjust the initial refractive index of the electrochromic layer 130 based on the light intensity and / or color purity of the light emitted by the light-emitting element 120 at a positive viewing angle.

[0054] Specifically, the initial refractive index n0 of the electrochromic layer 130 does not necessarily have to passively accept the inherent value of the material. Instead, it can be used as an actively designed degree of freedom for adjustment. By pre-setting and adjusting n0, the electrochromic layer 130 can produce a beneficial modulation effect on the emitted light of the light-emitting element 120 at a positive viewing angle. Specifically, this can enhance the emitted light intensity at a positive viewing angle, adjust the hue of the emitted light, and improve color purity.

[0055] It should be noted that this function does not conflict with the aforementioned technical solution of dynamically adjusting the refractive index of the electrochromic layer 130 based on the current viewing angle; the two belong to different levels of control mechanisms. The former's function is to dynamically adjust the refractive index of the electrochromic layer 130 according to the real-time viewing angle detected by the eye-tracking sensor 200 during the operation of the display module, in order to compensate for the optical path difference over a large viewing angle. The function of this optional embodiment is to optimize the initial refractive index n0 of the electrochromic layer 130 during the setting or calibration phase based on the actual luminous characteristics (light intensity and / or color purity) of the light-emitting element 120 at a positive viewing angle, so that the electrochromic layer 130 is already in the optimal optical state conducive to obtaining high brightness and high color purity positive viewing angle emission without the application of dynamic compensation voltage. The two complement each other, jointly achieving high-quality display of the display panel across the entire viewing angle range.

[0056] In one implementation, the processor 300 adjusts the initial refractive index of the electrochromic layer 130 to maximize the light intensity emitted from the positive viewing angle. Specifically, during the initial calibration phase of the display module, the processor 300 controls the application of a series of different bias voltages to the electrochromic layer 130, causing the refractive index of the electrochromic layer 130 to change stepwise within a certain range. In each step, the processor 300 acquires the light intensity data of the light-emitting element 120 from the positive viewing angle through an optical detection device (such as a photodiode or spectrometer) located inside or outside the display panel 100. The processor 300 performs correlation analysis between the light intensity and the corresponding refractive index, finds the refractive index that maximizes the light intensity, sets this value as the initial refractive index n0 of the electrochromic layer 130, and stores it in the processor 300's memory unit. Subsequently, when the display module is working normally, the processor 300 maintains the refractive index of the electrochromic layer 130 at this optimized value without applying a dynamic compensation voltage.

[0057] In another implementation, the processor 300 adjusts the initial refractive index of the electrochromic layer 130 to optimize the color purity of the emitted light at the normal viewing angle. Color purity can be quantitatively evaluated by the deviation of the full width at half maximum (FWHM) or CIE color coordinates from the standard color gamut. During the calibration phase, the processor 300 also controls the step change of the refractive index of the electrochromic layer 130, while simultaneously acquiring the emitted spectrum at the normal viewing angle of the light-emitting element 120 and calculating the color purity index under each refractive index state. The processor 300 sets the refractive index corresponding to the optimal color purity as the initial refractive index n0. This optimization process is particularly important for blue sub-pixels because blue light-emitting materials typically have a broad spectrum. By using the microcavity effect in conjunction with the optimization of the refractive index of the electrochromic layer, the blue spectrum can be effectively narrowed, improving the color purity of the blue sub-pixels and thus expanding the overall color gamut of the display panel.

[0058] Figure 7 yes Figure 2 A cross-sectional view of the display panel along B-B', see reference. Figure 1 , Figure 2 and Figure 7 In some alternative embodiments, the vertical projection of the light-emitting layer 123 onto the substrate 110 lies within the vertical projection of the same electrochromic layer 130 onto the substrate 110.

[0059] Specifically, the vertical projection of the light-emitting layer 123 onto the substrate 110 refers to the planar area obtained by orthographically projecting the light-emitting layer 123 onto the plane of the substrate 110 along a direction perpendicular to the surface of the substrate 110. This projection area corresponds to the actual area occupied by the light-emitting layer 123 on the plane of the display panel 100. For the display panel 100, each of the multiple light-emitting elements 120 has an independent light-emitting layer 123, thus there are multiple vertical projections of the light-emitting layer 123, each corresponding to the light-emitting area of ​​each sub-pixel.

[0060] The vertical projection of the light-emitting layer 123 onto the substrate 110 lies within the vertical projection of the electrochromic layer 130 onto the substrate 110. That is, the electrochromic layer 130 extends continuously in a direction parallel to the substrate 110, and its coverage encompasses the light-emitting layers 123 of all light-emitting elements 120 in the display area. This coverage relationship ensures that light rays emitted from the light-emitting layer 123 at any angle toward the electrochromic layer 130 (including light rays emitted perpendicularly at a normal viewing angle and lateral light rays emitted at a certain tilt angle) will all pass through the electrochromic layer 130 in their propagation path. Specifically, for light rays at a normal viewing angle, which are emitted from the light-emitting layer 123 in a direction perpendicular to the substrate and fall within the coverage area of ​​the electrochromic layer 130 in the vertical projection relationship, they will inevitably pass through the electrochromic layer 130. For lateral tilted light, although its actual geometric propagation path has an angle with the vertical direction, since the vertical projection of the light-emitting layer 123 is completely within the vertical projection of the electrochromic layer 130, and the distance between the electrochromic layer 130 and the light-emitting layer 123 is usually much smaller than the extension dimension of the electrochromic layer 130 in the planar direction, the tilted light is still within the planar coverage of the electrochromic layer 130 when it reaches the height of the electrochromic layer 130 in all angle ranges on the light-emitting side of the light-emitting layer 123.

[0061] Since the electrochromic layer 130 covers the entire vertical projection of the light-emitting layer 123, light emitted from any light-emitting element 120, regardless of its emission angle, will pass through the electrochromic layer 130 after leaving the light-emitting element 120. This ensures that the electrochromic layer 130 modulates the emitted light from all light-emitting areas of the display panel 100. Therefore, the viewing angle compensation effect can be uniformly applied to the entire display area, avoiding inconsistencies in the display image where some parts are compensated and others are not.

[0062] Meanwhile, the electrochromic layer 130 can be prepared through a single-layer coating, vapor deposition, or chemical vapor deposition process. This process is simple and efficient, avoiding the increased complexity and cost associated with multiple alignment and patterning steps, thus improving production efficiency and product yield. Furthermore, the continuous electrochromic layer 130 can be directly driven without requiring separate driving circuits for each sub-pixel or color region. The driving voltage output by the processor 300 allows for synchronous changes in the refractive index of the entire electrochromic layer 130. This unified driving method features simple control logic, easy driving circuit design, and high reliability, avoiding uneven compensation issues caused by parameter differences between numerous independent driving units.

[0063] Figure 8 This is a flowchart of a driving method for a display module provided in this disclosure, combined with... Figures 1-3 and Figure 8This disclosure provides a driving method for a display module, which is applied to the display module provided in this disclosure.

[0064] The driving methods include: Step S10: Real-time detection of the user's current visual orientation; Step S20: Adjust the refractive index of the electrochromic layer according to the current viewing angle.

[0065] Specifically, this disclosure provides a driving method for a display module, applied to the display module provided in this disclosure. The display module includes a display panel 100. The display panel 100 includes a substrate 110 and a plurality of light-emitting elements 120 arranged in an array on one side of the substrate 110. The light-emitting elements 120 are top-emitting OLED devices, and each light-emitting element 120 includes a first electrode 121, a second electrode 122, and a light-emitting layer 123 located between the first electrode 121 and the second electrode 122. The second electrode 122 is located on the side of the light-emitting layer 123 away from the substrate 110. The first electrode 121 is a total internal reflection electrode, and the second electrode 122 is a semi-transparent and semi-reflective electrode. A Fabry-Perot optical microcavity is formed between the first electrode 121 and the second electrode 122. Photons generated by the light-emitting layer 123 are reflected back and forth within the microcavity and interfere. Light of a specific wavelength is resonantly enhanced and then efficiently emitted from the direction away from the substrate 110 from the second electrode 122, thereby significantly improving the forward brightness.

[0066] Figure 4 yes Figure 2 The diagram shown illustrates a type of light pattern on a display panel. (Reference) Figure 4 Photons generated by the light-emitting layer 123 are reflected back and forth and interfere within the microcavity formed between the first electrode 121 and the second electrode 122. Light of wavelength that satisfies the resonance condition is coherently enhanced within the microcavity and is emitted from the side of the second electrode 122 away from the substrate 110, forming outgoing light rays.

[0067] In this diagram, ray L1 represents the light emitted from the frontal viewing direction (i.e., perpendicular to the surface of the display panel), and ray L2 represents the light emitted from the lateral viewing direction (i.e., at a certain angle θ to the normal direction of the display panel). For the frontal viewing ray L1, it is emitted along the normal direction of the display panel, and its round-trip propagation path within the microcavity is perpendicular to the microcavity. Its effective optical path is the product of the physical thickness of the microcavity and the refractive index of each layer of the medium. For the lateral viewing ray L2, because the light propagates at an inclined angle and is reflected within the microcavity, its actual geometric path for round-trip propagation within the microcavity is longer than that of the frontal viewing ray L1. However, it is important to note that the effective optical path of microcavity interference depends not only on the geometric path length but also on the phase jump generated at the reflection interface. Under large viewing angles, the reflection phase of the light at the second electrode 122 (semi-transparent and semi-reflective electrode) changes significantly with increasing incident angle, causing the total phase change accumulated between the two reflections of ray L2 to change relative to the frontal viewing ray L1. Considering the combined effects of geometric path changes and reflection phase changes, the effective interference optical path of the lateral viewing angle ray L2 is significantly shorter than that of the frontal viewing angle ray L1, meaning the equivalent microcavity's optical length is narrower at large viewing angles. A stronger microcavity effect results in more significant resonance enhancement at the frontal viewing angle, leading to higher luminous brightness and color purity. However, this also increases the microcavity's directivity, causing more severe brightness attenuation and color shift at large viewing angles, and narrowing the effective viewing angle range of the display panel. If the microcavity effect is weakened to widen the viewing angle, it must come at the cost of sacrificing brightness at the frontal viewing angle and increasing device power consumption.

[0068] Based on this, the display panel 100 also includes an electrochromic layer 130, which is located on the side of the second electrode 122 away from the substrate 110. The electrochromic layer 130 is made of a material whose refractive index can change with the applied voltage. The vertical projection of the light-emitting layer 123 onto the substrate 110 lies within the vertical projection of the electrochromic layer 130 onto the substrate 110. That is, the electrochromic layer 130 completely covers the light-emitting area in the horizontal direction. This ensures that light rays at all angles emitted from the light-emitting layer 123 (including frontal and lateral wide-angle light rays) must pass through the electrochromic layer 130 after leaving the microcavity. The display module also includes an eye-tracking sensor 200 and a processor 300. The processor 300 is electrically connected to both the eye-tracking sensor 200 and the display panel 100. The processor 300 can be directly electrically connected to the electrochromic layer 130. The eye-tracking sensor 200 collects the user's gaze direction information in real time and calculates the angle between the user's current line of sight and the normal of the display panel 100, i.e., the current viewing angle direction, using an algorithm. After receiving this viewing angle data, the processor 300 dynamically calculates the refractive index adjustment required to compensate for the microcavity optical path difference shift at this viewing angle, based on a built-in optical compensation algorithm, and then applies a corresponding driving voltage to the electrochromic layer 130. Under voltage drive, the electrochromic layer 130 rapidly changes its molecular orientation or band state, causing its refractive index to precisely change to the target value, thus achieving real-time adjustment of the optical path length of light passing through it. In other words, this disclosure dynamically compensates for the optical path difference of light at large viewing angles by adjusting the refractive index of the electrochromic layer 130 according to the current viewing angle direction, keeping the optical length of the equivalent microcavity stable at different viewing angles, thereby maintaining consistent resonance conditions, effectively suppressing the drift of white light color coordinates with viewing angle, and significantly improving the color fidelity of the display image at large viewing angles.

[0069] Furthermore, this disclosure does not alter the microcavity structure and light-emitting characteristics of the light-emitting element 120 itself, nor does it block or absorb any emitted light. The compensation is achieved entirely by adjusting the refractive index of the electrochromic layer 130. Therefore, the display panel 100 retains its advantages of high luminous efficiency, high brightness, and low power consumption at a normal viewing angle, while simultaneously enhancing the wide viewing angle display effect, achieving a balance between high efficiency and wide viewing angle.

[0070] like Figure 9 As shown, Figure 9This is a plan view of a display device provided in this disclosure. The embodiment of this disclosure provides a display device 1000, which includes a display module 400 provided in this disclosure embodiment. It is understood that the display device provided in this disclosure embodiment can be any electronic product with display function, including but not limited to the following categories: mobile phones, televisions, laptops, desktop monitors, tablet computers, digital cameras, smart bracelets, smart glasses, in-vehicle displays, medical devices, industrial control equipment, touch interactive terminals, etc. This disclosure embodiment does not impose any special limitations on these categories.

[0071] The display device provided in this embodiment has the same technical features as the display module provided in the above embodiment, so it can also solve the same technical problems and achieve the same technical effects.

[0072] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0073] The above description is merely a specific embodiment of this disclosure, enabling those skilled in the art to understand or implement it. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this disclosure. Therefore, this disclosure is not to be limited to the embodiments described herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A display module, characterized in that, include: The display panel, the eye-tracking sensor, and the processor are electrically connected to the display panel and the eye-tracking sensor, respectively. The display panel includes: Substrate; Multiple light-emitting elements are located on one side of the substrate. Each light-emitting element includes a first electrode, a second electrode, and a light-emitting layer located between the first electrode and the second electrode. The second electrode is located on the side of the light-emitting layer away from the substrate. The first electrode is a total reflection electrode, and the second electrode is a semi-transparent and semi-reflective electrode. An electrochromic layer is located on the side of the second electrode away from the substrate, and the vertical projection of the light-emitting layer on the substrate is located within the vertical projection of the electrochromic layer on the substrate; Eye-tracking sensors are used to detect the current viewing direction of the user's eyes in real time; The processor is used to adjust the refractive index of the electrochromic layer according to the current viewing direction.

2. The display module according to claim 1, characterized in that, The electrochromic layer is made of liquid crystal or semiconductor material.

3. The display module according to claim 1, characterized in that, The display panel further includes a third electrode, which is located on the side of the second electrode away from the substrate, and the third electrode is a semi-transparent and semi-reflective electrode; The electrochromic layer is located between the second electrode and the third electrode.

4. The display module according to claim 1, characterized in that, The display panel further includes an encapsulation layer located on the side of the light-emitting element away from the substrate, and the encapsulation layer includes a first inorganic encapsulation layer and a second inorganic encapsulation layer. The electrochromic layer is located between the first inorganic encapsulation layer and the second inorganic encapsulation layer.

5. The display module according to claim 1, characterized in that, The processor is used to calculate the compensated optical path difference based on the current viewing direction, and adjust the refractive index of the electrochromic layer based on the compensated optical path difference.

6. The display module according to claim 5, characterized in that, The processor is used to calculate the compensated optical path difference according to the following formula: ； in, To compensate for the optical path difference, The optical path difference of the light emitted by the light-emitting element at a positive viewing angle. The angle between the current viewing direction and the positive viewing direction is given.

7. The display module according to claim 6, characterized in that, The processor is used to adjust the refractive index of the electrochromic layer according to the following formula: ； in, The refractive index of the electrochromic layer after adjustment. is the initial refractive index of the electrochromic layer.

8. The display module according to claim 1, characterized in that, The processor is also used to adjust the initial refractive index of the electrochromic layer based on the light intensity and / or color purity of the light emitted by the light-emitting element at a positive viewing angle.

9. The display module according to claim 1, characterized in that, The vertical projection of the light-emitting layer onto the substrate lies within the vertical projection of the electrochromic layer onto the substrate.

10. A driving method for a display module, characterized in that, Applied to the display module according to any one of claims 1-9; the driving method includes: Real-time detection of the user's current eye position; Adjust the refractive index of the electrochromic layer according to the current viewing angle.

11. A display device, characterized in that, The display device includes the display module according to any one of claims 1-9.

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