A method for improving light extraction efficiency of a silicon-based microdisplay

Abstract

The present application relates to the technical field of micro display, and especially relates to a method for improving light extraction efficiency of a silicon-based micro display, wherein a TFLN film obtained by peeling from an LNOI substrate is attached to a TFE encapsulation layer of a top-emitting OLED device through a transfer process to form a composite light extraction structure in which light is emitted to air after sequentially passing through an organic light-emitting layer, a semi-transparent cathode layer, a CPL cover layer, the TFE encapsulation layer and the TFLN film, wherein the thickness of the TFLN film is controlled to be lambda / 2n~lambda / n, lambda is the emission wavelength of the organic light-emitting layer in the top-emitting OLED device, and n is the refractive index of the TFLN material. The present application prepares micro-nano light extraction structures such as nano-gratings, photonic crystals and tapered structures on the surface of the TFLN film, and effectively avoids the role bias problem existing in the traditional MLA light extraction structure by using the wide-band and wide-angle response characteristics of the micro-nano light extraction structures, so that the display viewing angle uniformity is significantly improved.

Description

Technical Field

[0001] This invention relates to the field of microdisplay technology, specifically to a method for improving the light extraction efficiency of silicon-based microdisplays. Background Technology

[0002] OLEDoS combines the self-emissive properties of OLED with the precision driving advantages of silicon-based semiconductors, making it a core component in high-end display fields such as near-eye displays and automotive HUDs. With the increasing popularity of AR / VR in consumer applications, the requirements for brightness, power consumption, and lifespan of OLEDoS are becoming increasingly stringent, and light extraction efficiency is the core optical parameter that determines the performance of these three aspects.

[0003] Currently, mainstream top-emitting silicon-based OLED devices suffer from significant optical loss bottlenecks: the light emitted by the organic light-emitting layer undergoes total internal reflection at the interfaces between different layers within the device, with approximately 70% to 80% of the light being confined within the device to form waveguide modes, failing to effectively escape into the air. This results in an external quantum efficiency that is generally below 20%, making it difficult to meet the application requirements of high brightness and low power consumption.

[0004] To address the aforementioned low light extraction efficiency, existing technologies typically employ a light extraction scheme that fabricates a microlens array (MLA) on the device surface. However, this approach is prone to causing severe pixel crosstalk issues within the microlens array. Since the size of the microlens is usually comparable to or larger than that of a single pixel, cross-coupling of light emitted from adjacent pixels can occur, resulting in decreased display contrast, color distortion, and severely impacting display quality. Furthermore, the fabrication of microlens arrays requires high-precision imprinting molds and complex alignment processes. During mass production, issues such as lens deformation and positional deviations can easily arise, leading to poor consistency in device optical performance, low yield, and high manufacturing costs. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a method for improving the light extraction efficiency of silicon-based microdisplays. This method has the advantages of having a micro-nano light extraction structure with a size smaller than a single pixel and a wide-band, wide-angle response, while solving the problems of pixel crosstalk and severe positional bias that are easily caused by traditional microlens arrays (MLAs).

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0007] A method for improving the light extraction efficiency of silicon-based microdisplays includes the following steps:

[0008] The TFLN film obtained from the LNOI substrate is attached to the TFE encapsulation layer of the top-emitting OLED device through a transfer process, forming a composite light-emitting structure in which light passes sequentially from the organic light-emitting layer through the semi-transparent cathode layer, CPL capping layer, TFE encapsulation layer, and TFLN film before being emitted into the air.

[0009] The thickness of the TFLN film is controlled to be λ / 2n~λ / n, where λ is the emission wavelength of the organic light-emitting layer in the top-emitting OLED device, and n is the refractive index of the TFLN material.

[0010] Preferably, the TFLN film peeling preparation step specifically includes:

[0011] S1. Photoresist is sequentially coated, exposed, developed, and etched on an LNOI substrate to obtain a patterned TFLN layer and a SiO2 insulating layer.

[0012] S2. Photoresist is coated on the patterned TFLN layer surface to form a photoresist protective layer covering the TFLN layer and a chain structure for suspending the TFLN.

[0013] S3. The sacrificial portion of the SiO2 insulating layer is removed by selective etching to obtain a TFLN sheet suspended above the LNOI substrate.

[0014] Preferably, the transfer process employs the PDMS elastic stamp transfer method, specifically: using a PDMS elastic stamp to pick up the suspended TFLN sheet, align it, and attach it to the surface of the top-emitting OLED device that has completed TFE encapsulation and OC planarization layer preparation.

[0015] Preferably, after the bonding is completed, a low-temperature bonding treatment is performed with a bonding temperature ≤150℃ to improve the interfacial adhesion between the TFLN film and the TFE encapsulation layer.

[0016] Preferably, after the TFLN film is attached, the photoresist protective layer on the surface of the TFLN film is removed by an oxygen plasma process to expose the surface of the TFLN film.

[0017] Preferably, a micro-nano light extraction structure is prepared on the upper surface of the TFLN film, wherein the micro-nano light extraction structure includes any one or more combinations of nanogratings, photonic crystals, conical structures, and pyramidal structures.

[0018] Preferably, the micro-nano light extraction structure is prepared by electron beam lithography combined with ICP etching, and its structural size is smaller than the size of a single pixel in a top-emitting OLED device.

[0019] Preferably, a refractive index matching layer is provided between the TFLN film and the TFE encapsulation layer, and the refractive index of the refractive index matching layer is between the refractive index of the TFLN film and the refractive index of the TFE encapsulation layer.

[0020] It includes a silicon substrate, a first ITO anode layer, a metal reflective layer, a second ITO anode layer, an organic light-emitting layer, a semi-transparent cathode layer, a CPL capping layer, a TFE encapsulation layer, and a TFLN light extraction layer, which are stacked sequentially.

[0021] The TFLN light extraction layer is a TFLN thin film obtained by peeling off from the LNOI substrate, with a thickness of λ / 2n to λ / n, where λ is the emission wavelength of the organic light-emitting layer and n is the refractive index of the TFLN material.

[0022] By employing the above technical solution, the present invention provides a method for improving the light extraction efficiency of silicon-based microdisplays, which has at least the following beneficial effects:

[0023] 1. The method for improving the light extraction efficiency of silicon-based microdisplays involves preparing micro-nano light extraction structures such as nanogratings, photonic crystals, and conical structures on the surface of TFLN thin films. By utilizing their wide-band and wide-angle response characteristics, the method effectively avoids the role bias problem existing in traditional MLA light extraction structures and significantly improves the uniformity of display viewing angle.

[0024] 2. The method for improving the light extraction efficiency of silicon-based microdisplays uses a TFLN thin film as an independent light extraction layer. By taking advantage of its excellent optical properties of having no intrinsic absorption in the visible light band (450~650nm) and a transmittance of over 98%, it eliminates the additional light loss introduced by traditional light extraction materials such as MLA and scattering films, and significantly improves the light extraction efficiency of the device.

[0025] 3. The method for improving the light extraction efficiency of silicon-based microdisplays adopts a heterogeneous integration process that involves peeling off the TFLN thin film from the LNOI substrate and then transferring and bonding it at low temperature. The entire process temperature is ≤150℃, which is fully compatible with existing silicon-based OLED mass production lines and will not cause any thermal damage to the prepared organic light-emitting layer, electrodes and CMOS driving circuit.

[0026] 4. This method for improving the light extraction efficiency of silicon-based microdisplays physically blocks the propagation of light between adjacent pixels by controlling the size of the micro-nano light extraction structure to be smaller than the size of a single pixel in the silicon-based microdisplay. This completely solves the pixel crosstalk problem inherent in traditional MLA light extraction structures and significantly improves display contrast and color purity. Attached Figure Description

[0027] The accompanying drawings, which are provided to further illustrate the invention, constitute a part of this application:

[0028] Figure 1 This is a schematic diagram of the structure of a conventional silicon-based top-emitting OLED device and a microlens array (MLA) light extraction layer in the prior art;

[0029] Figure 2 This is a schematic diagram of the silicon-based top-emitting OLED device, the TFLN light extraction layer, and the surface micro / nano light extraction structure of the present invention.

[0030] Figure 3 This is a schematic diagram of the stacked structure of an LNOI wafer;

[0031] Figure 4 This is a schematic diagram of the patterned TFLN layer and the SiO2 insulating layer.

[0032] Figure 5 A schematic diagram of a TFLN layer with a photoresist protective layer covering its surface and forming a suspension chain structure;

[0033] Figure 6 A schematic diagram of the structure of a TFLN sheet that is finally suspended above an LNOI substrate after the SiO2 sacrificial layer is etched;

[0034] Figure 7 A schematic diagram of the structure for transferring and low-temperature bonding TFLN sheets to a silicon-based OLED device that has completed TFE encapsulation and OC planarization;

[0035] Figure 8 A schematic diagram of the overall device structure after removing the photoresist protective layer on the TFLN thin film surface;

[0036] Figure 9 A schematic diagram of the final device structure after fabricating a micro / nano photoextraction structure on the surface of a TFLN thin film;

[0037] Figure 10 This is a schematic diagram of the disassembled structure of the silicon-based microdisplay of the present invention.

[0038] Figure label:

[0039] 1. Silicon substrate; 2. First ITO anode layer; 3. Metal reflective layer; 4. Second ITO anode layer; 5. Organic light-emitting layer; 6. Semi-transparent cathode layer; 7. CPL capping layer; 8. TFE encapsulation layer; 9. TFLN light extraction layer. Detailed Implementation

[0040] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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 are within the scope of protection of the present invention.

[0041] The following describes, with reference to the accompanying drawings, a method for improving the light extraction efficiency of a silicon-based microdisplay, according to some embodiments of the present invention.

[0042] Example 1:

[0043] Combination Figures 1-9 As shown, the present invention provides a method for improving the light extraction efficiency of silicon-based microdisplays, comprising the following steps:

[0044] The TFLN film obtained from the LNOI substrate is attached to the TFE encapsulation layer 8 of the top-emitting OLED device through a transfer process, forming a composite light-emitting structure in which light passes sequentially from the organic light-emitting layer 5 through the semi-transparent cathode layer 6, the CPL capping layer, the TFE encapsulation layer, and the TFLN film before being emitted into the air. The thickness of the TFLN film is controlled to be λ / 2n~λ / n, where λ is the emission wavelength of the organic light-emitting layer 5 in the top-emitting OLED device, and n is the refractive index of the TFLN material.

[0045] TFLN films exhibit no intrinsic absorption in the visible light band of 450~650nm and have a transmittance of ≥98%, effectively avoiding the additional light loss of traditional light extraction materials. Subsequently, micro-nano light extraction structures such as nanogratings, photonic crystals, and conical structures can be fabricated on the surface of TFLN films according to light extraction requirements to further improve light extraction efficiency and enhance angular characteristics.

[0046] The specific steps for preparing the TFLN film by peeling are as follows:

[0047] S1. Photoresist is sequentially coated, exposed, developed, and etched on the LNOI substrate to obtain a patterned TFLN layer and a SiO2 insulating layer. The etching process adopts ICP dry etching process to ensure that the edge perpendicularity and surface roughness of the TFLN film meet the optical grade requirements.

[0048] S2. Photoresist is coated on the patterned TFLN layer to form a photoresist protective layer covering the TFLN layer and a tethering structure for suspending the TFLN. The photoresist protective layer is used to prevent the TFLN film from being damaged during subsequent etching, and the tethering structure is used to maintain the mechanical connection between the TFLN layer and the LNOI substrate to prevent the TFLN layer from falling off after the sacrificial layer is etched.

[0049] S3. The sacrificial portion of the SiO2 insulating layer is removed by selective etching to obtain a TFLN film suspended above the LNOI substrate. The etching process uses an etching solution that is highly selective to SiO2 and non-corrosive to TFLN and photoresist to ensure the integrity of the TFLN film.

[0050] Furthermore, the transfer process employs the PDMS flexible stamp transfer method, specifically: using a PDMS flexible stamp to pick up the suspended TFLN sheet, align it, and attach it to the surface of the top-emitting OLED device that has completed TFE encapsulation and OC planarization layer preparation.

[0051] After attachment, a low-temperature bonding process is performed with a bonding temperature ≤150℃. This process enhances the interfacial adhesion between the TFLN film and the TFE encapsulation layer 8 through interfacial molecular interactions, preventing the TFLN film from detaching in subsequent processes. This low-temperature bonding process will not cause thermal damage to the fabricated OLED device and can be directly integrated into existing silicon-based OLED mass production lines.

[0052] Example 2:

[0053] Combination Figures 1-9 As shown in Example 1, a low-temperature bonding treatment is performed after attachment, with a bonding temperature ≤150℃, to improve the interfacial adhesion between the TFLN film and the TFE encapsulation layer 8. After the TFLN film and TFE encapsulation layer 8 are attached via PDMS transfer, they only rely on van der Waals forces to achieve initial bonding, resulting in weak interfacial adhesion and easy detachment in subsequent processes. Low-temperature bonding activates the thermal motion of interfacial molecules through heating, promoting a chemical reaction between the hydroxyl groups on the TFLN surface and the functional groups on the TFE encapsulation layer 8 surface, forming covalent bonds, thereby significantly improving the interfacial bonding strength. The bonding temperature is strictly controlled below 150℃ because the organic light-emitting layer 5 and electrode materials of silicon-based OLED devices are sensitive to high temperatures. Exceeding this temperature will lead to thermal decomposition of organic materials and oxidation of electrodes, causing a decrease in device brightness, shortened lifespan, or even failure. High-strength interfacial connection is achieved through covalent bonding, preventing the TFLN film from detaching during subsequent photolithography and etching processes.

[0054] Specifically, after attachment, the photoresist protective layer on the TFLN film surface is removed using an oxygen plasma process, exposing the TFLN film surface. Oxygen plasma is a mixture of active oxygen ions, oxygen atoms, and excited-state oxygen molecules generated by the ionization of oxygen under a high-frequency electric field. These active oxygen particles have strong oxidizing properties and can react with the organic polymers in the photoresist, decomposing them into carbon dioxide, water, and other volatile small molecule gases, which are then discharged through a vacuum system, thus achieving dry removal of the photoresist. Simultaneously, the oxygen plasma also etches and activates the TFLN film surface, introducing a large number of active functional groups such as hydroxyl groups to increase the surface energy.

[0055] Furthermore, a micro / nano light extraction structure is fabricated on the upper surface of the TFLN thin film. This structure includes any one or more combinations of nanogratings, photonic crystals, conical structures, and pyramidal structures. In top-emitting OLED devices, the light emitted from the organic light-emitting layer 5 undergoes total internal reflection at the interfaces between layers, with approximately 70%–80% of the light confined within the device to form waveguide modes, preventing emission. This is the main reason for the low light extraction efficiency of OLEDs. The micro / nano light extraction structure on the TFLN surface can break the total internal reflection condition, coupling the waveguide mode light into the air through diffraction and scattering, thereby significantly improving the light extraction efficiency. Different types of micro / nano structures possess different optical properties: nanogratings have directional light extraction characteristics, effectively improving viewing angle characteristics; photonic crystals have wide-band light extraction characteristics, suitable for full-color displays; and conical and pyramidal structures have wide-angle light extraction characteristics, enabling omnidirectional light extraction.

[0056] Example 3:

[0057] Combination Figures 1-9 As shown in Example 1, the micro / nano light extraction structure is fabricated using electron beam lithography combined with ICP etching. The structure size is smaller than a single pixel size in a top-emitting OLED device. Electron beam lithography uses a focused electron beam to create nanoscale patterns on photoresist, enabling the fabrication of micro / nano structures of arbitrary shapes. ICP etching uses high-density plasma to perform anisotropic dry etching of the TFLN thin film, achieving optical-grade structures with sidewall perpendicularity >85° and surface roughness <0.5nm, ensuring consistent light extraction efficiency. By strictly controlling the structure size to below the size of a single pixel, each micro / nano structure corresponds to only one pixel's light-emitting area, physically blocking light propagation between adjacent pixels and completely avoiding pixel crosstalk.

[0058] Furthermore, a refractive index matching layer is disposed between the TFLN film and the TFE encapsulation layer 8. The refractive index of the refractive index matching layer is between that of the TFLN film and the TFE encapsulation layer 8. When light is incident from one medium to another, it will be reflected at the interface, and the reflectivity is proportional to the difference in refractive index between the two media. The refractive index of the TFLN film is approximately 2.2 at 550 nm, while the refractive index of the semi-transparent cathode layer TFE encapsulation layer 8 at the 550 nm wavelength of the semi-transparent cathode layer is typically 1.5 to 1.7. The large refractive index difference between the two will cause approximately 10% to 12% of the light to be reflected at the interface and unable to enter the TFLN light extraction layer 9. The refractive index matching layer, by inserting a material with a suitable refractive index between the two media, can effectively reduce the refractive index difference at the interface, reduce interface reflection loss, and allow more light to enter the TFLN light extraction layer 9.

[0059] As can be seen from the embodiments, in Figure 3 Based on LNOI, by utilizing processes such as coating, exposure, development, and etching, patterned TFLN and SiO2 insulating layers that meet the requirements are obtained, such as... Figure 4 ;exist Figure 4 Based on this, processes such as coating, exposure, and development are used to obtain the photoresist coating layer and its chains, such as... Figure 5 ;exist Figure 5 Based on this, an etching process is used to obtain the final suspended TFLN sheet, such as... Figure 6 ;Will Figure 6 The suspended TFLN sheet is transferred to the device with completed TFE and OC planarization layers using a PDMS elastic stamp, and low-temperature bonding is performed to improve interface adhesion, such as... Figure 7 ;exist Figure 7 Based on this, the photoresist is removed using oxygen plasma to expose the TFLN, such as... Figure 8 ;exist Figure 8 Based on this, micro-nano gratings are fabricated on the surface of TFLN using processes such as coating, exposure, development, and etching. Figure 9 .

[0060] Example 4:

[0061] Combination Figure 10 As shown, based on Embodiment 1, the system includes a silicon substrate 1, a first ITO anode layer 2, a metal reflective layer 3, a second ITO anode layer 4, an organic light-emitting layer 5, a semi-transparent cathode layer 6, a CPL capping layer 7, a TFE encapsulation layer 8, and a TFLN light extraction layer 9, which are stacked sequentially. The silicon substrate 1 integrates a CMOS driving circuit, providing nanosecond-level precise current driving for each sub-pixel, which is the foundation for achieving ultra-high resolution. The first ITO anode layer 2 serves as an adhesion transition layer, enabling low-resistance electrical connection between the driving circuit and the upper electrode, while also improving the adhesion between the metal layer and the silicon substrate 1. The metal reflective layer 3 (typically a high-reflectivity silver layer) and the top semi-transparent cathode layer 6 form a Fabry-Perot optical microcavity, which totally reflects the light emitted downwards from the organic light-emitting layer 5 back to the light source, while selectively enhancing specific wavelengths through the microcavity resonance effect. Long light output and compressed spectral half-width at half-maximum; the second ITO anode layer 4 planarizes the surface roughness of the metal reflective layer 3, and at the same time serves as a hole injection layer to efficiently inject holes into the organic light-emitting layer 5; the organic light-emitting layer 5 is the electroluminescent core, where electrons and holes radiatively recombine to generate photons; the semi-transparent cathode layer 6 (ultra-thin silver or ITO / silver composite layer) has both electron injection and high light transmittance characteristics, allowing light to exit from the top of the device; the CPL capping layer 7 protects the fragile semi-transparent cathode layer 6 from damage by subsequent processes, while planarizing the surface to improve the adhesion and sealing of the TFE encapsulation layer 8; the TFE thin film encapsulation layer forms a dense water vapor and oxygen barrier through an inorganic / organic alternating stacking structure; the topmost TFLN light extraction layer 9 breaks the total internal reflection limitation inside the device, coupling the light that was originally confined to the waveguide mode into the air;

[0062] Since the preparation temperature of high-quality single-crystal TFLN thin films is usually >500℃, which is much higher than the thermal decomposition temperature of silicon-based OLED organic materials (<200℃), they cannot be directly deposited on OLED devices. To solve the above problem, the TFLN photoextraction layer 9 is a TFLN thin film obtained by peeling off the LNOI substrate, with a thickness of λ / 2n~λ / n, where λ is the emission wavelength of the organic light-emitting layer 5 and n is the refractive index of the TFLN material. First, a high-quality single-crystal TFLN thin film is grown on the LNOI (lithium niobate on insulating layer) substrate. The suspended TFLN sheet is obtained by etching the SiO2 sacrificial layer. Then, it is transferred and bonded to the OLED encapsulation layer at low temperature using a PDMS elastic stamp. The temperature throughout the process is ≤150℃, completely avoiding thermal damage.

[0063] It should be noted that 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 process, method, article, or apparatus.

[0064] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for improving the light extraction efficiency of silicon-based microdisplays, characterized in that, Includes the following steps: The TFLN film obtained from the LNOI substrate is attached to the TFE encapsulation layer (8) of the top-emitting OLED device through a transfer process, forming a composite light-emitting structure in which light passes sequentially from the organic light-emitting layer (5) through the semi-transparent cathode layer (6), CPL capping layer (7), TFE encapsulation layer (8), and TFLN film before being emitted into the air. The thickness of the TFLN film is controlled to be λ / 2n~λ / n, where λ is the emission wavelength of the organic light-emitting layer (5) in the top-emitting OLED device, and n is the refractive index of the TFLN material.

2. The method for improving the light extraction efficiency of silicon-based microdisplays according to claim 1, characterized in that, The specific steps for preparing the TFLN film by peeling are as follows: S1. Photoresist is sequentially coated, exposed, developed, and etched on an LNOI substrate to obtain a patterned TFLN layer and a SiO2 insulating layer. S2. Photoresist is coated on the patterned TFLN layer surface to form a photoresist protective layer covering the TFLN layer and a chain structure for suspending the TFLN. S3. The sacrificial portion of the SiO2 insulating layer is removed by selective etching to obtain a TFLN sheet suspended above the LNOI substrate.

3. The method for improving the light extraction efficiency of silicon-based microdisplays according to claim 1, characterized in that, The transfer process employs the PDMS elastic stamp transfer method, specifically: using a PDMS elastic stamp to pick up the suspended TFLN sheet, align it, and attach it to the surface of the top-emitting OLED device that has completed TFE encapsulation and OC planarization layer preparation.

4. The method for improving the light extraction efficiency of silicon-based microdisplays according to claim 3, characterized in that, After the bonding is completed, a low-temperature bonding process is performed with a bonding temperature ≤150℃ to improve the interfacial adhesion between the TFLN film and the TFE encapsulation layer (8).

5. The method for improving the light extraction efficiency of silicon-based microdisplays according to claim 3, characterized in that, After attachment, the photoresist protective layer on the TFLN film surface is removed by oxygen plasma process, exposing the TFLN film surface.

6. The method for improving the light extraction efficiency of silicon-based microdisplays according to claim 1, characterized in that, A micro-nano light extraction structure is prepared on the upper surface of the TFLN film. The micro-nano light extraction structure includes any one or more combinations of nanogratings, photonic crystals, conical structures, and pyramidal structures.

7. The method for improving the light extraction efficiency of silicon-based microdisplays according to claim 6, characterized in that, The micro-nano light extraction structure is prepared by electron beam lithography combined with ICP etching, and its structural size is smaller than the size of a single pixel in a top-emitting OLED device.

8. The method for improving the light extraction efficiency of silicon-based microdisplays according to claim 1, characterized in that, A refractive index matching layer is provided between the TFLN film and the TFE encapsulation layer (8), and the refractive index of the refractive index matching layer is between the refractive index of the TFLN film and the refractive index of the TFE encapsulation layer (8).

9. A high light-efficiency silicon-based microdisplay, characterized in that, The material includes a silicon substrate (1), a first ITO anode layer (2), a metal reflective layer (3), a second ITO anode layer (4), an organic light-emitting layer (5), a semi-transparent cathode layer (6), a CPL cover layer (7), a TFE encapsulation layer (8), and a TFLN light extraction layer (9) stacked sequentially. The TFLN photoextraction layer (9) is a TFLN thin film obtained by peeling off the LNOI substrate, with a thickness of λ / 2n~λ / n, where λ is the emission wavelength of the organic light-emitting layer (5) and n is the refractive index of the TFLN material.

Images