TW202407176A - Post-processing optical loss recovery methods - Google Patents

Abstract

The disclosed method for recovering optical properties of transparent substrates may include performing a post-etching annealing process on a transparent substrate. The method may also include applying a plasma treatment to the transparent substrate, performing an atomic layer etching treatment on the transparent substrate, and/or performing a cleaning process. Various other methods, devices, and systems are also disclosed.

Description

Post-processing light loss recovery methods

The present invention relates to a post-processing light loss recovery method. Cross-references to related applications

This application claims the rights and interests of U.S. Provisional Application No. 63/325,882 filed on March 31, 2022 and U.S. Non-provisional Application No. 18/159,842 filed on January 26, 2023. The disclosure content is quoted in full. method is incorporated into this article.

Substrates with optical properties (eg, transparent substrates) can be used to fabricate a variety of structures and devices with optical properties, such as waveguides. However, some fabrication processes (eg, etching processes such as reactive ion etching and ion beam etching) applied to substrates can cause undesirable changes to the substrate, such as inducing surface roughness and/or changing surface composition. These changes can interfere with the optical properties of the substrate, such as transmittance, refractive index, and scattering losses.

One aspect of the present invention is a method for restoring optical properties of a transparent substrate. The method includes: performing a post-etch annealing process on the transparent substrate.

Methods according to aspects of the invention further include applying a plasma treatment to the transparent substrate.

The method according to the aspect of the invention further includes performing an atomic layer etching process on the transparent substrate.

Methods according to aspects of the invention further include subsequently performing a cleaning process.

Methods according to aspects of the invention further include subsequently applying a surface passivation layer to the transparent substrate.

In the method according to the aspect of the invention, the post-etch annealing process includes an oxidation annealing process.

In the method according to the aspect of the invention, the post-etch annealing process includes a reduction annealing process.

In the method according to the aspect of the present invention, the post-etching annealing process includes an oxidation annealing process and a reduction annealing process in sequence.

Methods according to aspects of the invention further include subsequently performing a cleaning process.

Methods according to aspects of the invention further include subsequently applying a surface passivation layer to the transparent substrate.

In the method according to the aspect of the present invention, the post-etch annealing process is performed at 1600 degrees Celsius or lower.

In the method according to the aspect of the invention, the post-etch annealing process is performed at or below 1400 degrees Celsius.

In the method according to the aspect of the present invention, the post-etch annealing process is performed at 1200 degrees Celsius or lower.

In the method according to the aspect of the invention, the annealing process includes using a mixture of at least one of Ar gas or N ₂ gas and H ₂ gas, wherein the H ₂ gas accounts for approximately 10% of the gas mixture by volume. 10% or less; the annealing process is performed at about 1200 degrees Celsius or less than 1200 degrees Celsius; and the annealing process is performed for about 3 hours or less.

The method according to the aspect of the invention further includes a plasma treatment process, wherein: the plasma treatment process includes using a plasma treatment mixture of at least one of Ar gas or N ₂ gas and H ₂ gas, wherein the _H gas constitutes about 10% or less by volume of the plasma processing gas mixture; the plasma processing process is performed at about 500 degrees Celsius or less; the plasma processing process is performed for about 1 hour or less ; and the plasma treatment process is performed with a radio frequency power of about 1 kilowatt or less.

Methods according to aspects of the invention further comprise an annealing process, wherein: the annealing process includes using a gas at least partially containing _O2 ; the annealing process is performed at about 1200 degrees Celsius or less; and the annealing process is performed at about 1200 degrees Celsius or less. 3 hours or less.

In the method according to the aspect of the present invention, the annealing process is performed at about 500 degrees Celsius or less; the annealing process is performed at about 1 hour or less; and the annealing process is performed by about 1 kilowatt or less Performs at 1 kilowatt of RF power.

Methods according to aspects of the invention further include performing a wet cleaning process.

Another aspect of the invention is a device including an etched transparent substrate modified by a post-etch annealing process.

Yet another aspect of the invention is a system including a head mounted display including a waveguide modified by a post-etch annealing process.

This disclosure describes various manufacturing processes for recovering transparent substrates after initial processing. These processes can restore and/or improve the optical properties of the substrate by, for example, reducing surface roughness, restoring and/or modifying the surface composition of the substrate, and the like. Processing described herein may include, but is not limited to, oxidation or reduction annealing, plasma treatment, atomic layer etching, cleaning processes, and/or application of surface passivation layers.

The transparent substrate may include any of a variety of materials, including, but not limited to, lithium niobate, zinc sulfide, indium tin oxide, aluminum oxide, titanium oxide, hafnium oxide, silicon carbide, quartz, diamond, and/or glass.

In some examples, processing to restore and/or modify the transparent substrate after initial processing (eg, etching, such as ion beam etching) may include performing an oxidation anneal on the substrate. In some examples, the oxidation anneal can be performed at temperatures between 10 degrees Celsius and 1200 degrees Celsius. In some examples, the oxidation anneal can be performed at temperatures between 10 degrees Celsius and 1400 degrees Celsius. In some examples, the oxidation anneal can be performed at temperatures between 10 degrees Celsius and 1600 degrees Celsius. In some examples, the oxidation anneal can be performed at a temperature between 1200 degrees Celsius and 1400 degrees Celsius.

Additionally or alternatively, methods for restoring and/or modifying a transparent substrate after initial processing may include performing a reduction anneal on the substrate. In some examples, reduction annealing can be performed at temperatures between 10 degrees Celsius and 1200 degrees Celsius. In some examples, reduction annealing can be performed at temperatures between 10 degrees Celsius and 1400 degrees Celsius. In some examples, reduction annealing can be performed at temperatures between 10 degrees Celsius and 1600 degrees Celsius. In some examples, reduction annealing can be performed at temperatures between 1200 degrees Celsius and 1400 degrees Celsius.

The annealing steps described herein can be performed in any suitable environment. In some examples, the annealing steps described herein may be performed in Ar gas, _H gas, or mixtures thereof. By way of example, and without limitation, the annealing step may be performed in a H ₂ /Ar gas mixture having 3% H ₂ or less, 4% H ₂ or _less by volume , 5% H ₂ or less, 10% H ₂ or less, and/or between 1% and 4% H ² . In some examples, the gas composition may include one or more oxidizing gases (eg, steam, O ₂ ), one or more inert gases (eg, Ar, N ₂ ), and/or one or more reducing gases (eg, NH ₃ , CH ₄ ).

The annealing steps described herein can be performed at any suitable amount of pressure. By way of example, and without limitation, the annealing steps described herein may be performed at a pressure between 0.01 atmosphere and 1 atmosphere. In some examples, the annealing steps described herein may be performed at pressures greater than 1 atmosphere. In some examples, the annealing steps described herein may be performed between 400 and 600 Torr, between 300 and 700 Torr, between 200 and 800 Torr, and/or between 100 and 900 Torr.

In some examples, the method may also include performing a plasma treatment on the substrate in addition to and/or in lieu of performing the one or more annealing steps. For example, the method may include performing an oxidative plasma treatment on the substrate. Additionally or alternatively, the method may include performing a reducing plasma treatment on the substrate. Plasma treatment may include any form of oxidative plasma treatment and/or reducing plasma treatment. Plasma treatment may include suitable types of plasma, including, but not limited to, argon-based plasma, helium-based plasma, nitrogen-based plasma, oxygen-based plasma, and/or hydrogen-based plasma.

In some examples, in addition to any combination of the steps described above, the method may include performing an atomic layer etching process on the substrate.

In some examples, the method may sequentially include both oxidation and reduction treatments. In some examples, the method may include first an oxidation treatment and then a reduction treatment. In some examples, the method may first include a reduction process and then an oxidation process.

In some examples, in addition to any combination of the steps described above, the method may include cleaning the substrate (eg, after the processing described above).

In some examples, the method may include applying a surface passivation layer (eg, after the processing described above) in addition to any combination of the steps described above. Any suitable deposition technique may be used to apply the surface passivation layer. For example, atomic layer deposition can be used to apply a surface passivation layer.

As described above, in some examples, methods for restoring and/or modifying a transparent substrate after initial processing may include performing an oxidation annealing and/or cleaning process on the substrate. In this manner, the method can clean surface contaminants from the substrate and reintroduce a protective surface oxide layer to the substrate. The method may include any suitable oxidation annealing and/or cleaning process. In some examples, the method may include a dry oxidation process.

The dry oxidation process can be performed for any suitable amount of time. In some examples, the dry oxidation process may be performed for a period ranging from one second to 10 hours. In some examples, the dry oxidation process may be performed for a period ranging from one minute to two hours. The dry oxidation process can be performed at any suitable temperature. For example, the dry oxidation process can be performed at a temperature in the range of 10 degrees Celsius to 1200 degrees Celsius, in the range of 10 degrees Celsius to 1000 degrees Celsius, in the range of 10 degrees Celsius to 600 degrees Celsius, in the range of 10 degrees Celsius to 400 degrees Celsius, or in the range of 10 degrees Celsius to 100 degrees Celsius. performed at temperatures within the range. The dry oxidation process can be performed at any suitable pressure. For example, a dry oxidation process can be performed at pressures ranging from 0.1 Torr to 100 Torr. The dry oxidation process can be performed using any suitable oxidizing gas. For example, the dry oxidation process can be performed using O ₂ , Ar, Cl ₂ , HBr, SF ₆ , N ₂ O, and/or CO ₂ . In some examples, dry oxidation processes can be performed using a mixture of gases. For example, the dry oxidation process can be performed using a mixture of O ₂ and Ar or a mixture of O ₂ and N ₂ .

The dry oxidation process can use radio frequency plasma within any suitable power range. For example, dry oxidation processes can use radio frequency plasma between zero and six kilowatts. In addition, the dry oxidation process can be performed within any suitable bias power range. For example, a dry oxidation process can be performed at a bias power between zero and six kilowatts.

As discussed above, methods for restoring and/or modifying a transparent substrate after initial processing may include performing an oxidation annealing and/or cleaning process on the substrate. In some examples, the oxidation annealing and/or cleaning process may include a wet oxidation process.

The wet oxidation process can be performed in any suitable manner and with any suitable parameters. For example, a wet oxidation process may include a cleaning process using a solution of sulfuric acid and hydrogen peroxide. For example, the wet oxidation process can use piranha solution, NANO-STRIP solution, etc.

The wet oxidation process can be performed at any suitable temperature. In some examples, the wet oxidation process can be performed at a temperature range between 10 degrees Celsius and 30 degrees Celsius. The wet oxidation process can be performed at any suitable relative humidity level. In some examples, the wet oxidation process can be performed within a relative humidity range of 10% to 100%.

In some examples, the wet oxidation process may include applying hydrofluoric acid to the surface of the substrate. In some examples, hydrofluoric acid can be applied at a temperature ranging from 10 degrees Celsius to 30 degrees Celsius.

In some examples, a wet oxidation process may include applying water to the surface of the substrate. In some examples, water can be applied at a temperature ranging from 100 degrees Celsius to 400 degrees Celsius.

In some examples, the wet oxidation process may include a steam annealing process. Steam annealing can be performed at any suitable temperature. For example, steam annealing can be performed at temperatures ranging from 20 degrees Celsius to 1200 degrees Celsius.

As discussed above, methods for restoring and/or modifying a transparent substrate after initial processing may include performing a reduction annealing and/or cleaning process on the substrate. In some examples, the reduction process may anneal the crystal defects and/or trap states from the substrate. Additionally or alternatively, the reduction process can cap reactive interfacial bonds. In some examples, the reduction annealing and/or cleaning process may include a dry reduction process.

The dry reduction process can be performed for any suitable length of time. In some examples, the dry reduction process can be performed for a duration ranging from one second to three hours. In some examples, the dry reduction process may be performed for a duration ranging from one minute to two hours.

The dry reduction process can be performed at any suitable temperature. For example, the dry reduction process may be performed at a temperature in the range of 10 degrees Celsius to 1200 degrees Celsius, in the range of 10 degrees Celsius to 1000 degrees Celsius, in the range of 10 degrees Celsius to 600 degrees Celsius, or in the range of 10 degrees Celsius to 400 degrees Celsius.

The dry reduction process can be performed at any suitable pressure. For example, dry reduction processes can be performed at pressures ranging from 0.1 Torr to 800 Torr.

The dry reduction process can be performed using any suitable gas composition. For example, the dry reduction process can be performed using H ₂ , a mixture of H ₂ and N ₂ , a mixture of H ₂ and Ar, NH ₃ , CO, a mixture of H ₂ and He, and/or CH ₄ .

The dry reduction process can use RF plasma within any suitable power range. For example, dry reduction processes can use radio frequency plasma between zero and six kilowatts. In addition, the dry reduction process can be performed within any suitable bias power range. For example, a dry reduction process can be performed at a bias power between zero and six kilowatts.

In some examples, methods for restoring and/or modifying a transparent substrate after initial processing may include by first applying oxidized ash to the substrate and then performing a wet piranha clean on the substrate (e.g., using sulfuric acid and hydrogen peroxide solution) to clean residual foreign matter from the substrate.

In some examples, oxidation of ash can be performed using _O2 . Oxidation of ash can be performed at any suitable pressure. In some examples, oxidation of ash can be performed in the range of 100 mTorr to 2 Torr. For example, oxidation of ash may be performed at approximately 500 mTorr. Oxidizing the ash may involve the use of radio frequency plasma within any suitable power range. In some examples, oxidizing the ash may include using radio frequency plasma between 100 and 600 watts. In one example, oxidizing the ash may include using approximately 300 watts of radio frequency plasma. Oxidation of ash can be performed for any suitable amount of time. In some examples, oxidizing ash may be performed for a period ranging from 1 minute to 10 minutes. In one example, oxidation of ash can be performed for approximately 4 minutes.

In some examples, wet piranha cleaning can be performed in about 10 minutes. In some examples, wet piranha cleaning can be performed at temperatures ranging from 10 degrees Celsius to 30 degrees Celsius.

In some examples, methods for restoring and/or modifying a transparent substrate may include repairing damage to the substrate during an ion beam etching process by applying a plasma to the substrate using a mixture of _H2 and Ar. The _H2 /Ar plasma can be applied at any suitable temperature. In some examples, the _H2 /Ar plasma can be applied at a temperature in the range of 300 degrees Celsius to 600 degrees Celsius. In one example, the _H2 /Ar plasma can be applied at about 400 degrees Celsius. The gas may be applied at any suitable flow rate and/or ratio of flow rates. For example, in some examples, Ar gas may be applied at a greater flow rate than _H gas. In various examples, Ar gas may be applied at a flow rate that is at least 3 times greater than _H2 gas, at least 5 times greater than _H2 gas, or at least 7 times greater than _H2 gas. In one example, Ar gas can be applied at a flow rate approximately nine times greater than _H gas. By way of example, Ar gas may be applied at a flow rate of 135 sccm/min and _H gas may be applied at a flow rate of 15 sccm/min.

The _H2 /Ar plasma can be applied at any suitable power level. For example, _H2 /Ar plasma can be applied at power levels in the range of 150 watts to 300 watts. In one example, the _H2 /Ar plasma can be applied at a power level of approximately 200 watts. The _H2 /Ar plasma can be applied at any suitable pressure. In some examples, the _H2 /Ar plasma can be applied at a pressure in the range of 1 Torr to 10 Torr. In one example, the _H2 /Ar plasma can be applied at a pressure of approximately 4 Torr. The _H2 /Ar plasma can be applied for any suitable amount of time. In some examples, the _H2 /Ar plasma can be applied for a period of time ranging from 1 minute to 1 hour. In one example, the _H2 /Ar plasma may be applied for a period of approximately 15 minutes.

In some examples, methods for restoring and/or modifying a transparent substrate may first include applying a plasma to the substrate using a mixture of _H2 and Ar (e.g., according to the example of applying _H2 /Ar plasma described above any combination). The method may next include applying an oxidizing plasma to the substrate. The oxidation plasma may use any suitable gas or combination of gases, including, for example, _O2 and Ar.

The oxidizing plasma can be applied at any suitable temperature. In some examples, the oxidation plasma can be applied at a temperature in the range of 300 degrees Celsius to 600 degrees Celsius. In one example, the oxidation plasma can be applied at about 400 degrees Celsius. The gas may be applied at any suitable flow rate and/or ratio of flow rates. For example, in some examples, Ar gas may be applied at a greater flow rate than O _gas . In various examples, Ar gas may be applied at a flow rate that is at least 1.5 times greater than _O2 gas, at least 2 times greater than _H2 gas, or at least 3 times greater than _O2 gas. In one example, Ar gas can be applied at a flow rate approximately 4 times greater than _O2 gas. By way of example, Ar gas can be applied at a flow rate of 80 sccm/min and _O2 gas can be applied at a flow rate of 20 sccm/min.

The oxidizing plasma can be applied at any suitable power level. For example, the oxidizing plasma can be applied at a power level in the range of 150 watts to 300 watts. In one example, the oxidizing plasma may be applied at a power level of approximately 200 watts. The oxidizing plasma can be applied at any suitable pressure. In some examples, the oxidation plasma can be applied at a pressure in the range of 1 Torr to 10 Torr. In one example, the oxidation plasma can be applied at a pressure of about 4 Torr. The oxidizing plasma can be applied for any suitable amount of time. In some examples, the oxidizing plasma may be applied for a period of time ranging from 1 minute to 1 hour. In one example, the oxidizing plasma may be applied for a period of approximately 15 minutes.

The method may next include cleaning the substrate using a buffered oxide etch process. The buffered oxide etch process may include applying a solution of ammonium fluoride and hydrofluoric acid. The buffered oxide etch process can be performed for any suitable amount of time. In some examples, the buffered oxide etch process may be performed for a time period in the range of 1 minute to 1 hour. In some examples, the buffered oxide etch process can be performed for about 10 minutes. In some examples, the buffered oxide etch process may be performed at temperatures ranging from 10 degrees Celsius to 30 degrees Celsius.

In one example, a method for restoring and/or modifying a transparent substrate after damage caused during an ion beam etching process may include applying oxidized ash. In some examples, oxidation of ash can be performed using _O2 . Oxidation of ash can be performed at any suitable pressure. In some examples, oxidation of ash can be performed in the range of 100 mTorr to 2 Torr. For example, oxidation of ash may be performed at approximately 500 mTorr. Oxidizing the ash may involve the use of radio frequency plasma within any suitable power range. In some examples, oxidizing the ash may include using radio frequency plasma between 100 and 600 watts. In one example, oxidizing the ash may include using approximately 300 watts of radio frequency plasma. Oxidation of ash can be performed for any suitable amount of time. In some examples, oxidizing ash may be performed for a period ranging from 1 minute to 10 minutes. In one example, oxidation of ash can be performed for approximately 4 minutes.

In some examples, the methods described herein for restoring and/or modifying transparent substrates can produce transformed substrates. The converted substrate may have undergone a manufacturing process (such as reactive ion etching or ion beam etching) and, nonetheless, maintain one or more optical properties close to, at, or better than the specifications of the substrate prior to the manufacturing process. In some examples, the transformed substrate can operate as an optical waveguide. In some examples, such optical waveguides may be used in augmented reality devices and/or virtual reality devices.

Figure 1 illustrates an example method 100 for post-processing light loss recovery. As shown in Figure 1, at step 110, the method 100 optionally includes etching the transparent substrate. By way of example, the transparent substrate may be an optical waveguide under fabrication. In some examples, the method may begin after the optical waveguide in fabrication has been etched.

At step 120, method 100 may include post-etch annealing of the transparent substrate. Post-etch annealing may include an oxidation anneal step 122, a reduction annealing step 124, or both. If the post-etch anneal includes both step 122 and step 124, these steps may occur in any order (eg, step 122 is performed before step 124 in order 126, or step 124 is performed before step 122 in order 128). The post-etch anneal of method 100 may include any of the techniques, conditions, and/or parameters for annealing described herein.

At step 130, method 100 may include plasma treatment of the transparent substrate. In some examples, step 130 may be omitted from method 100. The plasma treatment of method 100 may include any of the techniques, conditions, and/or parameters described herein for plasma treatment.

At step 140, method 100 may include cleaning of the transparent substrate. Cleaning may include a wet cleaning step 142 and/or a dry cleaning step 144 . Wet cleaning step 142 and dry cleaning step 144 may occur in any order. In some examples, step 140 may be omitted from method 100. Cleaning of method 100 may include any of the techniques, conditions, and/or parameters described herein for cleaning.

At step 150, method 100 may include applying a surface passivation layer to the transparent substrate. In some examples, step 150 may be omitted from method 100. The surface passivation layer step of method 100 may include any of the techniques, conditions, and/or parameters described herein for applying a surface passivation layer.

Figure 2 illustrates an example test procedure 200 for post-processing light loss recovery. As shown in FIG. 2 , the testing procedure 200 may begin with a transparent substrate 210 . The initial absorbance of the transparent substrate 210 may be measured at one or more locations (eg, such as the front and back sides of the transparent substrate 210 at location 214, as shown in Figure 212). Transparent substrate 210 can be cleaned and a protective layer can be applied, resulting in transparent substrate 220 .

A photolithography process may be performed on the transparent substrate 220 , and then ion beam etching (IBE) may be performed on the transparent substrate 220 , followed by a resist ashing process. Half of the transparent substrate 220 may be shielded, and half of the transparent substrate 220 may be exposed to an etching process, thereby producing a transparent substrate 230 .

A protective layer ashing process may be performed on the transparent substrate 230 , and a cleaning process may be performed on the transparent substrate 230 , thereby producing a transparent substrate 240 . Absorbance measurements of transparent substrate 240 may be taken at one or more locations, such as location 214. After performing the absorbance measurement, one or more of the post-etch processes described herein may be applied to transparent substrate 240 , resulting in transparent substrate 250 . Absorbance measurements of transparent substrate 250 may be taken at one or more locations, such as location 214.

Figure 3 illustrates example light loss after etching. As shown in Figure 3, after an etching process (eg, the etching process described with respect to Figure 2), the transparent substrate may experience light loss across wavelengths. For example, graph 302 shows a transparent substrate experiencing an average absolute change in light loss between 0.078% and 0.143% after an etching process. Graph 304 shows the percent absorbance across wavelengths as measured at various transparent substrate positions, such as position 214 illustrated in graph 212 of FIG. 2 . For example, post-etch residue and increased surface roughness can cause light loss. High light losses can be associated with a negative impact on the optical performance of various optical devices (eg, waveguide throughput).

Figure 4 illustrates example post-processing of light loss recovery. As shown in Figure 4, the transparent substrate may exhibit reduced light loss after a post-etch recovery process, such as one or more of the processes described herein. For example, graph 402 shows that a transparent substrate experiences an average reduction in light loss across wavelengths of greater than 100%. Graph 404 shows the percent absorbance across wavelengths as measured at various transparent substrate locations, such as location 214 illustrated in graph 212 of FIG. 2 . Reduced light loss can be associated with a positive impact on the optical performance of various optical devices (eg, waveguide throughput).

Figure 5 illustrates example post-processing of light loss recovery. As shown in Figure 5, graph 500 shows hydrogen concentration at various depths for six transparent substrate samples. All samples may have undergone an etch process, but only samples 3 and 6 may have been processed with a post-process recovery process, such as one or more of the post-etch recovery steps described herein (e.g., including H ₂ /Ar plasma processing steps). As can be seen in graph 500, samples 3 and 6 may exhibit hydrogen concentrations near the surface that are significantly higher than those of the remaining samples.

Specific examples of the invention may include or be implemented in conjunction with various types of artificial reality systems. Artificial reality can be a form of reality that has been adjusted in some way before being presented to the user. It can include, for example, virtual reality, augmented reality, mixed reality, mixed reality or some combination thereof and/or derivative. Artificial reality content may include entirely computer-generated content or computer-generated content combined with captured (eg, real-world) content. Artificial reality content may include video, audio, haptic feedback, or some combination thereof, any of which may be presented in a single channel or in multiple channels (such as creating a three-dimensional (3D) effect for the viewer) Effect of stereoscopic video). In addition, in some specific examples, artificial reality may also be related to applications, products, products that are used, for example, to generate content in the artificial reality and/or are otherwise used in the artificial reality (e.g., performing activities in the artificial reality). Accessories, services, or some combination thereof.

Artificial reality systems can be implemented in a variety of appearance sizes and configurations. Some artificial reality systems can be designed to work without near-eye displays (NEDs). Other artificial reality systems may include NEDs that also provide visibility into the real world (such as, for example, augmented reality system 600 in FIG. 6 ) or allow users to visually immerse themselves in artificial reality (such as, for example, FIG. 7 in the virtual reality system 700). While some artificial reality devices may be self-contained systems, other artificial reality devices may communicate and/or coordinate with external devices to provide artificial reality experiences to users. Examples of such external devices include handheld controllers, mobile devices, desktop computers, devices worn by the user, devices worn by one or more other users, and/or any other suitable external system.

Referring to Figure 6, augmented reality system 600 may include eyewear device 602 having a frame 610 configured to hold left and right display devices 615(A), 615(B) in front of the user's eyes. Display devices 615(A) and 615(B) may function together or independently to present an image or series of images to a user. Although augmented reality system 600 includes two displays, embodiments of the invention may be implemented in augmented reality systems with a single NED or more than two NEDs.

In some embodiments, augmented reality system 600 may include one or more sensors, such as sensor 640 . Sensors 640 may generate measurement signals in response to movement of augmented reality system 600 and may be located on virtually any portion of frame 610 . Sensor 640 may represent one or more of a variety of different sensing mechanisms, such as a position sensor, an inertial measurement unit (IMU), a depth camera assembly, a structured light emission device and/or detector, or any combination thereof. In some embodiments, augmented reality system 600 may or may not include sensor 640 or may include more than one sensor. In specific examples where sensor 640 includes an IMU, the IMU can generate calibration data based on measurement signals from sensor 640 . Examples of sensors 640 may include, but are not limited to, accelerometers, gyroscopes, magnetometers, other suitable types of sensors for detecting motion, sensors for error correction of IMUs, or some combination thereof.

In some examples, augmented reality system 600 may also include a microphone array having a plurality of sound transducers 620(A)-620(J), collectively referred to as sound transducers 620. Sound transducer 620 may represent a transducer that detects air pressure changes induced by sound waves. Each sound transducer 620 may be configured to detect sound and convert the detected sound into an electronic format (eg, analog or digital format). The microphone array in Figure 6 may include, for example, ten sound transducers: 620(A) and 620(B), which may be designed to be placed inside corresponding ears of the user; sound transducer 620(C) , 620(D), 620(E), 620(F), 620(G) and 620(H), which may be positioned at various positions on the frame 610; and/or the sound transducer 620(I) and 620(J), which may be positioned on the corresponding neckband 605.

In some embodiments, one or more of sound transducers 620(A)-(J) may serve as an output transducer (eg, a speaker). For example, sound transducers 620(A) and/or 620(B) may be earbuds or any other suitable type of headset or speaker.

The configuration of the sound transducer 620 of the microphone array may vary. Although augmented reality system 600 is shown in Figure 6 as having ten sound transducers 620, the number of sound transducers 620 may be greater or less than ten. In some embodiments, using a higher number of sound transducers 620 may increase the amount of audio information collected and/or the sensitivity and accuracy of the audio information. In contrast, using a lower number of sound transducers 620 may reduce the computing power required by the associated controller 650 to process the collected audio information. In addition, the position of each sound transducer 620 of the microphone array can be different. For example, the location of the sound transducers 620 may include a defined position with respect to the user, defined coordinates with respect to the frame 610, an orientation associated with each sound transducer 620, or some combination thereof.

Sound transducers 620(A) and 620(B) may be positioned on different parts of the user's ear, such as behind the auricle, behind the tragus, and/or within the auricle or fossa. Alternatively, in addition to the sound transducer 620 inside the ear canal, there may be additional sound transducers 620 on or around the ear. Positioning the sound transducer 620 proximate the user's ear canal allows the microphone array to collect information about how sound reaches the ear canal. By positioning at least two of the sound transducers 620 on either side of the user's head (eg, as binaural microphones), the augmented reality device 600 can simulate binaural hearing and capture the user's head Surrounding 3D stereo sound field. In some embodiments, sound transducers 620(A) and 620(B) may be connected to augmented reality system 600 via wired connection 630, and in other embodiments, sound transducers 620(A) and 620 (B) Can be connected to the augmented reality system 600 via a wireless connection (eg, Bluetooth connection). In still other embodiments, sound transducers 620(A) and 620(B) may not be used in conjunction with augmented reality system 600 at all.

Sound transducers 620 on frame 610 may be positioned in a number of different ways, including along the length of the temples, across the bridge, above or below display devices 615(A) and 615(B), or some combination thereof. Sound transducer 620 may also be oriented such that the microphone array can detect sound in a wide range of directions surrounding the user wearing augmented reality system 600. In some embodiments, an optimization process may be performed during manufacturing of augmented reality system 600 to determine the relative positioning of each sound transducer 620 in the microphone array.

In some examples, augmented reality system 600 may include or be connected to an external device (eg, a pair of devices), such as neckband 605 . Neckband 605 generally represents any type or form of paired device. Accordingly, the following discussion of neckband 605 may also apply to a variety of other paired devices, such as charging cases, smart watches, smartphones, wristbands, other wearable devices, handheld controllers, tablets, laptops , other external computing devices, etc.

As shown, neckband 605 may be coupled to eyewear device 602 via one or more connectors. Connectors may be wired or wireless, and may include electrical and/or non-electrical (eg, structural) components. In some cases, eyewear device 602 and neckband 605 may operate independently without any wired or wireless connection therebetween. Although FIG. 6 illustrates components of eyewear device 602 and neckband 605 in exemplary positions on eyewear device 602 and neckband 605 , these components may be located elsewhere and/or distributed differently on eyewear device 602 and/or On the neck strap 605. In some embodiments, components of eyewear device 602 and neckband 605 may be located on one or more additional peripheral devices paired with eyewear device 602, neckband 605, or some combination thereof.

Pairing an external device such as the neckband 605 with the augmented reality eyewear device can enable the eyewear device to achieve the appearance of a pair of glasses while still providing sufficient battery power and computing power for expansion capabilities. Some or all of the battery power, computing resources, and/or additional features of the augmented reality system 600 may be provided by the paired device or shared between the paired device and the eyewear device, thereby reducing the weight and heat distribution of the eyewear device as a whole. and appearance dimensions while still maintaining the desired functionality. For example, the neck strap 605 may allow components that would otherwise be included on an eyewear device to be included in the neck strap 605 because the user may bear a heavier weight load on the shoulders than the user would bear on the head. . The neckband 605 may also have a larger surface area to spread heat over it and disperse the heat to the surrounding environment. Thus, the neckband 605 may allow for greater battery and computing capacity than might otherwise be present on a stand-alone eyewear device. Because the weight carried in the neckband 605 can be less intrusive to the user than the weight carried in the eyewear device 602, the user can afford to wear the lighter eyewear device and carry or wear a pair. The duration of the device is greater than the length of time a user would endure wearing a heavier stand-alone eyewear device, thereby allowing the user to more fully integrate the artificial reality environment into daily activities.

Neckband 605 may be communicatively coupled with eyewear device 602 and/or other devices. These other devices may provide certain functionality to augmented reality system 600 (eg, tracking, positioning, depth mapping, processing, storage, etc.). In the specific example of Figure 6, neckband 605 may include two sound transducers (eg, 620(I) and 620(J)) that are part of a microphone array (or may form its own microphone sub-array) . Neckband 605 may also include a controller 625 and a power source 635.

Sound transducers 620(I) and 620(J) of neckband 605 may be configured to detect sounds and convert the detected sounds into an electronic format (analog or digital). In the specific example of Figure 6, sound transducers 620(I) and 620(J) may be positioned on neckband 605, thereby adding neckband sound transducers 620(I) and 620(J) to those positioned on The distance between other sound transducers 620 on the eyewear device 602. In some cases, increasing the distance between sound transducers 620 of a microphone array can improve the accuracy of beamforming performed by the microphone array. For example, if sound is detected by sound transducers 620(C) and 620(D) and the distance between sound transducers 620(C) and 620(D) is greater than, for example, sound transducers 620( D) and 620(E), the determined source location of the detected sound may be more accurate than if the sound was detected by sound transducers 620(D) and 620(E).

The controller 625 of the neckband 605 may process information generated by the sensors on the neckband 605 and/or the augmented reality system 600 . For example, controller 625 may process information from the microphone array describing sounds detected by the microphone array. For each detected sound, controller 625 may perform a direction-of-arrival (DOA) estimation to estimate the direction from which the detected sound reaches the microphone array. When the microphone array detects sound, the controller 625 may populate the audio data set with information. In specific examples where augmented reality system 600 includes an inertial measurement unit, controller 625 may calculate all inertial and spatial calculations based on the IMU located on eyewear device 602 . The connector can transmit information between the augmented reality system 600 and the neckband 605 and between the augmented reality system 600 and the controller 625 . This information may be in the form of optical data, electrical data, wireless data, or any other transmittable data form. Moving the processing of information generated by the augmented reality system 600 to the neckband 605 can reduce weight and heat in the eyewear device 602, thereby making the eyewear device more comfortable for the user.

Power supply 635 in neckband 605 can provide power to eyewear device 602 and/or neckband 605 . The power source 635 may include, but is not limited to, a lithium ion battery, a lithium polymer battery, a lithium primary battery, an alkaline battery, or any other form of power storage. In some cases, power supply 635 may be a wired power supply. Including the power supply 635 on the neckband 605 rather than on the eyewear device 602 may help better distribute the weight and heat generated by the power supply 635.

As mentioned, instead of fusing artificial reality with actual reality, some artificial reality systems may essentially replace one or more of the user's sensory perceptions of the real world with a virtual experience. One example of this type of system is a head-mounted display system, such as virtual reality system 700 in Figure 7, which primarily or completely covers the user's field of view. The virtual reality system 700 may include a front rigid body 702 and a strap 704 shaped to fit around the user's head. Virtual reality system 700 may also include output audio transducers 706(A) and 706(B). Additionally, although not shown in FIG. 7 , the front rigid body 702 may include one or more electronic components, including one or more electronic displays, one or more inertial measurement units (IMUs), one or more tracking transmitters. device or detector and/or any other suitable device or system for generating artificial reality experiences.

Artificial reality systems can include various types of visual feedback mechanisms. For example, the display device in the augmented reality system 600 and/or the virtual reality system 700 may include one or more liquid crystal displays (LCD), light emitting diode (LED) displays. ,, micro LED displays, organic LED (organic LED; OLED) displays, digital light project (DLP) micro displays, liquid crystal on silicon (LCoS) micro displays, and/or any other suitable type display screen. These artificial reality systems may include a single display screen for both eyes or may provide a display screen for each eye, which may allow additional flexibility for zoom adjustments or for correcting the user's refractive error. Some of these artificial reality systems may also include an optical subsystem with one or more lenses (e.g., concave or convex lenses, Fresnel lenses, adjustable liquid lenses, etc.) through which a user can or multiple lenses to view the display screen. These optical subsystems can be used for a variety of purposes, including collimating light (e.g., making an object appear at a greater distance than its physical distance), amplifying light (e.g., making an object appear larger than its actual size), and/or or relay light (relaying light to, for example, the viewer's eyes). These optical subsystems can be used in non-pupil-forming architectures (such as single lens configurations that directly collimate light but create so-called pincushion distortion) and/or in pupil-forming architectures (such as create so-called barrel distortion to eliminate pincushion distortion). Distorted multi-lens configuration).

In addition to or instead of using a display screen, some of the artificial reality systems described herein may also include one or more projection systems. For example, display devices in augmented reality system 600 and/or virtual reality system 700 may include micro-LED projectors that project light (using, for example, waveguides) into display devices that, for example, allow the environment to Light passes through a clear combiner lens. The display device can refract the projected light toward the user's pupil and can enable the user to view both artificial reality content and the real world simultaneously. Display devices can accomplish this using any of a variety of different optical components, including waveguide components (eg, holographic, planar, diffractive, polarizing, and/or reflective waveguide elements), light-manipulating surfaces, and elements (such as diffractive, reflective and refractive elements and gratings), coupling elements, etc. The artificial reality system may also be configured with any other suitable type or form of image projection system, such as a retina projector used in a virtual retina display.

The artificial reality systems described herein may also include various types of computer vision components and subsystems. For example, the augmented reality system 600 and/or the virtual reality system 700 may include one or more optical sensors, such as two-dimensional (2D) or 3D cameras, structured light transmitters, and detectors. sensors, time-of-flight depth sensors, single-beam or swept laser rangefinders, 3D LiDAR sensors, and/or any other suitable type or form of optical sensor. Artificial reality systems may process data from one or more of these sensors to identify the user's location, map the real world, provide the user with context about the real-world environment, and/or perform a variety of other functions.

In some examples, augmented reality system 600 and/or virtual reality system 700 may include and/or be examples of head mounted displays.

Artificial reality systems described herein may also include one or more input and/or output audio transducers. Output audio transducers may include voice coil speakers, ribbon speakers, electrostatic speakers, piezoelectric speakers, bone conduction transducers, cartilage conduction transducers, tragus vibration transducers, and/or any other suitable type or form. Audio transducer. Similarly, input audio transducers may include condenser microphones, dynamic microphones, ribbon microphones, and/or any other type or form of input transducer. In some embodiments, a single transducer can be used for both audio input and audio output.

In some specific examples, the artificial reality systems described herein may also include tactile (i.e., tactile) feedback systems that may be incorporated into headgear, gloves, bodysuits, handheld controllers, environmental devices ( For example, chairs, floor mats, etc.) and/or any other type of device or system. Tactile feedback systems can provide various types of skin feedback, including vibration, force, traction, texture and/or temperature. Tactile feedback systems can also provide various types of kinesthetic feedback, such as movement and compliance. Tactile feedback can be implemented using electric motors, piezoelectric actuators, fluidic systems, and/or many other types of feedback mechanisms. The haptic feedback system may be implemented independently of, within, and/or in combination with other artificial reality devices.

By providing tactile sensations, auditory content, and/or visual content, artificial reality systems can generate entire virtual experiences or enhance users' real-world experiences in a variety of situations and environments. For example, artificial reality systems can assist or expand the user's perception, memory or cognition in a specific environment. Some systems enhance a user's interactions with others in the real world or enable more immersive interactions with others in a virtual world. Artificial reality systems may also be used for teaching purposes (e.g., for teaching or training in schools, hospitals, government organizations, military organizations, commercial enterprises, etc.), entertainment purposes (e.g., for playing video games, listening to music, watching video content, etc.) and/or for accessibility purposes (e.g., as hearing aids, visual aids, etc.). Specific examples disclosed herein may enable or enhance a user's artificial reality experience in one or more of these contexts and environments and/or in other contexts and environments.

The process parameters and step sequences described and/or illustrated herein are given as examples only and may be changed as necessary. For example, although the steps illustrated and/or described herein may be shown or discussed in a particular order, such steps do not necessarily need to be performed in the order illustrated or discussed. Various illustrative methods described and/or illustrated herein may also omit one or more of the steps described or illustrated herein or include additional steps in addition to those disclosed.

The foregoing description has been provided to enable one of ordinary skill in the art to best utilize the various aspects of the illustrative embodiments disclosed herein. This illustrative description is not intended to be exhaustive or limited to any precise form disclosed. Many modifications and variations are possible without departing from the spirit and scope of the invention. The specific examples disclosed herein are to be considered in all respects as illustrative and not restrictive. Reference should be made to the appended patent applications and equivalents when determining the scope of the invention.

Unless otherwise indicated, the terms "connected to" and "coupled to" (and derivatives) as used in this specification and claims are to be construed as permitting both direct and indirect (i.e., via other elements or components) connections. Both. In addition, the term "a (a or an)" as used in this specification and the scope of the patent application is interpreted to mean "at least one of". Finally, for ease of use, the terms "include" and "have" (and derivatives) as used in this specification and claims are interchangeable with and have the same meaning as the word "includes."

100:Method 110: Steps 120: Steps 122: Oxidation annealing step 124: Reduction annealing step 126:Sequence 128:Sequence 130: Steps 140: Steps 142: Wet cleaning steps 144: Dry cleaning steps 150: Steps 200:Test program 210:Transparent substrate 212: Figure 214: Location 220:Transparent substrate 230:Transparent substrate 240:Transparent substrate 250:Transparent substrate 302: Chart 304: Curve graph 402: Chart 404: Curve graph 500: Chart 600:Augmented reality system 602: Glasses device 605: Neck strap 610:Framework 615(A):Display device 615(B):Display device 620: Sound transducer 620(A): Sound transducer 620(B): Sound transducer 620(C): Sound transducer 620(D): Sound transducer 620(E): Sound transducer 620(F): Sound transducer 620(G): Sound transducer 620(H): Sound transducer 620(I): Sound transducer 620(J): Sound transducer 625:Controller 630:Wired connection 635:Power supply 640: Sensor 650:Controller 700:Virtual Reality System 702: Front rigid body 704:With 706(A): Output audio transducer 706(B): Output audio transducer

The accompanying drawings illustrate several illustrative embodiments and are a part of this specification. Together with the following description, the drawings present and explain various principles of the invention. [Figure 1] illustrates an example method for post-processing light loss recovery. [Figure 2] illustrates an example test procedure for post-processing light loss recovery. [Figure 3] illustrates example light loss after etching. [Figure 4] illustrates example post-processing of light loss recovery. [Figure 5] illustrates example post-processing of light loss recovery. [Fig. 6] is an illustration of exemplary augmented reality glasses that may be used in conjunction with specific examples of the present invention. [FIG. 7] is an illustration of an exemplary virtual reality headset that may be used in conjunction with specific examples of the present invention. Throughout the drawings, the same reference numbers and descriptions indicate similar, but not necessarily identical, elements. While the illustrative embodiments described herein are susceptible to various modifications and alternative forms, certain embodiments have been shown by way of example in the drawings and will be described in detail herein. However, the illustrative embodiments described herein are not intended to be limited to the specific forms disclosed. The fact is that the present invention covers all modifications, equivalents and alternatives falling within the scope of the appended patent application.

100:Method

110: Steps

120: Steps

122: Oxidation annealing step

124: Reduction annealing step

126:Sequence

128:Sequence

130: Steps

140: Steps

142: Wet cleaning steps

144: Dry cleaning steps

150: Steps

Claims (20)

A method for restoring optical properties of a transparent substrate, the method comprising: A post-etch annealing process is performed on the transparent substrate. For example, the method of request item 1 further includes: Plasma treatment is applied to the transparent substrate. For example, the method of request item 2 further includes: An atomic layer etching process is performed on the transparent substrate. The method of claim 3 further includes subsequently performing a cleaning process. The method of claim 4, further comprising subsequently applying a surface passivation layer to the transparent substrate. The method of claim 1, wherein the post-etching annealing process includes an oxidation annealing process. The method of claim 1, wherein the post-etching annealing process includes a reduction annealing process. The method of claim 1, wherein the post-etching annealing process includes an oxidation annealing process and a reduction annealing process in sequence. The method of claim 1 further includes subsequently performing a cleaning process. The method of claim 1, further comprising subsequently applying a surface passivation layer to the transparent substrate. The method of claim 1, wherein the post-etching annealing process is performed at 1600 degrees Celsius or lower than 1600 degrees Celsius. The method of claim 1, wherein the post-etching annealing process is performed at 1400 degrees Celsius or lower than 1400 degrees Celsius. The method of claim 1, wherein the post-etching annealing process is performed at 1200 degrees Celsius or lower than 1200 degrees Celsius. The method of claim 1, wherein: the annealing process includes using a mixture of at least one of Ar gas or N ₂ gas and H ₂ gas, wherein the H ₂ gas accounts for about 10% or more of the gas mixture by volume. less; the annealing process is performed at about 1200 degrees Celsius or less; and the annealing process is performed for about 3 hours or less. The method of claim 14, further comprising a plasma treatment process, wherein: the plasma treatment process includes using a plasma treatment mixture of at least one of Ar gas or N ₂ gas and H ₂ gas, wherein the H ₂ The gas constitutes about 10% or less by volume of the plasma treatment gas mixture; the plasma treatment process is performed at about 500 degrees Celsius or less; the plasma treatment process is performed for about 1 hour or less; and The plasma treatment process is performed with radio frequency power of about 1 kilowatt or less. The method of claim 14, further comprising an annealing process, wherein: the annealing process includes the use of a gas at least partially containing _O2 ; the annealing process is performed at about 1200 degrees Celsius or less than 1200 degrees Celsius; and the annealing process is performed for about 3 hours or less than 3 hours. Such as the method of request item 16, wherein: The annealing process is performed at about 500 degrees Celsius or less; The annealing process is performed for about 1 hour or less than 1 hour; and The annealing process is performed with RF power of about 1 kilowatt or less. The method of claim 14 further includes performing a wet cleaning process. A device includes an etched transparent substrate modified by a post-etch annealing process. A system includes a head mounted display including a waveguide modified by a post-etch annealing process.