CN120802542A - Optical module, preparation method of optical module and optical system - Google Patents

Abstract

The embodiment of the application relates to an optical module, a preparation method thereof and an optical system. The optical module comprises a first functional substrate, a second functional substrate and an electrolyte layer. The first functional substrate comprises a first substrate, a first diffraction grating formed on a first surface of the first substrate, and a first electrochromic layer formed on a second surface of the first substrate opposite to the first surface. The second functional substrate comprises a second substrate, a second diffraction grating formed on a third surface of the second substrate, and a second electrochromic layer formed on a fourth surface of the second substrate opposite to the third surface, wherein the second surface and the fourth surface are arranged at intervals in a face-to-face manner. An electrolyte layer is sandwiched between the first electrochromic layer and the second electrochromic layer to constitute an electrochemical cell. By applying a variable voltage to the electrochemical cell, the effective refractive index of the second diffraction grating and the light absorption coefficient of the electrochemical cell can be changed, and the coupling angle and the light transmittance of the optical module can be dynamically regulated.

Description

Optical module, preparation method of optical module and optical system

Technical Field

The embodiment of the application relates to the technical field of optics, in particular to an optical module, a preparation method of the optical module and an optical system.

Background

In an optical system such as augmented reality (Augmented Reality, AR) glasses, a conventional optical module has a dimming function, and an optical waveguide sheet is generally adopted to package an electrochromic device externally. However, the scheme has the defects of large packaging thickness, influence on wearing comfort and light and thin design, more alignment times in the manufacturing process, reduction of production yield, fixed coupling angle of the grating, incapability of dynamically adjusting a light path, limited brightness adjustment range, limitation of a use scene, single control mechanism and lack of elasticity for dual regulation and control of refractive index and color.

Disclosure of Invention

In view of the foregoing, it is desirable to provide an optical module, a method for manufacturing the optical module, and an optical system for solving at least one of the above problems.

The first aspect of the present application provides an optical module. The optical module comprises a first functional substrate, a second functional substrate and an electrolyte layer. The first functional substrate comprises a first substrate, a first diffraction grating formed on a first surface of the first substrate, and a first electrochromic layer formed on a second surface of the first substrate, wherein the first surface is opposite to the second surface. The second functional substrate comprises a second substrate, a second diffraction grating formed on a third surface of the second substrate, and a second electrochromic layer formed on a fourth surface of the second substrate, wherein the third surface is opposite to the fourth surface, and the second surface and the fourth surface are arranged at intervals in a face-to-face manner. The electrolyte layer is sandwiched between the first electrochromic layer and the second electrochromic layer to form an electrochemical cell. By applying a variable voltage to the electrochemical cell, the effective refractive index of the second diffraction grating and the light absorption coefficient of the electrochemical cell can be changed, and the coupling angle and the light transmittance of the optical module can be dynamically regulated.

In the optical module of the related art, the diffraction grating and the electrochromic layer are designed as independent substrates, and the optical module of the embodiment of the application integrates the diffraction grating and the electrochromic layer into a double-sided design, wherein the first diffraction grating and the first electrochromic layer are independent, the functional layering is not interfered with each other, the first substrate is shared, the second diffraction grating and the second electrochromic layer are independent, the functional layering is not interfered with each other, and the second substrate is shared, so that the problems of large thickness and complex packaging existing in the scheme of the externally-hung electrochromic structure in the traditional optical module are solved, and the optical module is lighter and thinner and has shorter light path.

Functionally, the coupling angle of the grating is fixed, the optical path cannot be dynamically adjusted, and the brightness cannot be changed, while the optical module of the embodiment of the application uses the voltage input of the electrochemical unit, the effective refractive index change of the second diffraction grating and the light absorption coefficient change of the electrochemical unit are dynamically controlled, so that the light coupling angle is changed, the light coupling efficiency is improved, stray light is actively restrained, and display uniformity and the like are optimized.

In the optical module of the related art, multiple bonding processes are required, and the process is complex, but the optical module of the embodiment of the application is beneficial to reducing the pairing times because the diffraction grating and the electrochromic layer share the substrate.

In terms of cost, at least four substrates are needed in the optical module of the related art, and the preparation of each substrate is an independent process, so that the cost is high.

The second aspect of the present application provides a method for manufacturing an optical module, which includes:

providing a first functional substrate, wherein the first functional substrate is integrated with a first diffraction grating and a first electrochromic layer;

Providing a second functional substrate integrated with a second diffraction grating and a second electrochromic layer, and

The first functional substrate and the second functional substrate are assembled through an alignment and lamination process, and an electrolyte layer is formed between the first functional substrate and the second functional substrate to form an electrochemical unit.

The method for manufacturing an optical module according to the second aspect of the present application has at least the same advantages as those of the optical module according to the first aspect of the present application, and will not be described again.

A third aspect of the present application provides an optical system comprising the optical module of the first aspect of the present application and a control unit. The control unit is electrically connected with the electrochemical unit and is configured to send a variable voltage to the electrochemical unit to cooperatively regulate the effective refractive index and the light absorption coefficient.

The optical system of the third aspect of the present application has at least the same advantages as the optical module of the first aspect of the present application, and will not be described again.

Drawings

Fig. 1 is a schematic view of a partial cross-sectional structure of an optical module of the related art.

Fig. 2 is a schematic partial cross-sectional view of an optical module according to an embodiment of the application.

FIG. 3 is a graph showing the relationship between the light absorption coefficient and the coupling efficiency according to an embodiment of the present application.

FIG. 4 is a graph showing the relationship between refractive index variation and effective refractive index according to an embodiment of the present application.

FIG. 5 is a diagram showing the relationship between the effective refractive index of an optical module and the grating period and the coupling angle according to an embodiment of the present application.

FIG. 6 is a graph showing coupling efficiency profiles corresponding to different grating depths of a second diffraction grating in an optical module according to an embodiment of the present application.

Fig. 7 is a schematic structural diagram of an optical system according to an embodiment of the application.

Description of main reference numerals:

The application will be further described in the following detailed description in conjunction with the above-described figures.

Detailed Description

Fig. 1 is a schematic partial cross-sectional structure of a related art optical module 100'. The optical module 100' can be applied to full-color AR glasses, so that the AR glasses have dimming or color-changing functions. As shown in fig. 1, the optical module 100' includes a first layer substrate 1, a second layer substrate 2, a third layer substrate 3, a fourth layer substrate 4, a fifth layer substrate 5, an electrolyte layer 6, a lamination adhesive layer 7, a lamination adhesive layer 8, and a lamination adhesive layer 9.

In use, external ambient light is incident from the side of the first layer substrate 1. The fifth layer substrate 5 is adjacent to the eye E of the person. The fourth substrate 4 is used as a first optical waveguide for coupling light. The fifth layer substrate 5 acts as a second optical waveguide for coupling out light into the user's eye E. The fourth layer of substrate 4 and the fifth layer of substrate 5 are connected through the adhesive layer 9.

The third layer substrate 3 is connected with the fourth layer substrate 4 through the adhesive layer 8. The electrolyte layer 6 is sandwiched between the third layer substrate 3 and the second layer substrate 2. The electrolyte layer 6 may be an electrolyte gel layer and also serves to bond the third layer substrate 3 and the second layer substrate 2. The side of the third layer substrate 3 close to the electrolyte layer 6 is used for forming an upper electrochromic layer, and the side of the second layer substrate 2 close to the electrolyte layer is used for forming a lower electrochromic layer. The third layer substrate 3 and the second layer substrate 2 and the layers between them (such as the lower electrochromic layer, the lower electrochromic layer and the electrolyte layer 6) together constitute an electrochromic structure.

The first layer substrate 1 is used as a lens and is connected with the second layer substrate 2 through the adhesive layer 7.

The following definition is that the direction from the first layer substrate 1 to the fifth layer substrate 5 in the thickness direction Z of the optical module 100' is the outside-in direction. I.e. the direction in which the ambient light is located is outside and the direction in which the eyes of the user are located is inside.

As can be seen from fig. 1, the optical module 100' at least includes five substrates, three adhesive layers and one electrolyte adhesive layer, and has a large overall thickness. In addition, in the process, alignment and bonding are needed between every two substrates, so that four alignment and bonding processes are needed for five substrates. In addition, in the optical module 100', the coupling angle of the grating is fixed, the brightness cannot be effectively adjusted, and the control mechanism is single.

Fig. 1 illustrates an optical module of full-color AR glasses as an example. The optical module of the single-color AR glasses is different in that only one optical waveguide is needed to allow light with a specific wavelength to pass through (such as one of red light, green light or blue light), but it still needs four substrates, three times of alignment and lamination, and there is still a problem of single control mechanism.

Fig. 2 is a schematic partial cross-sectional view of an optical module 100 according to an embodiment of the application. As shown in fig. 2, the optical module 100 includes a first functional substrate 10, a second functional substrate 20, and an electrolyte layer 30.

The first functional substrate 10 includes a first substrate 11, a first diffraction grating 12 formed on one side of the first substrate 11, and a first electrochromic layer 13 formed on the other side of the first substrate 11. The first substrate 11 includes opposite first and second faces 11a and 11b. The first diffraction grating 12 is formed on the first surface 11a of the first substrate 11. The first electrochromic layer 13 is formed on the second surface 11b of the first substrate 11.

The second functional substrate 20 includes a second substrate 21, a second diffraction grating 22 formed on one side of the second substrate 21, and a second electrochromic layer 23 formed on the other side of the second substrate 21. The second substrate 21 includes opposite third and fourth faces 21c and 21d. The second diffraction grating 22 is formed on the third surface 21c, and the second electrochromic layer 23 is formed on the fourth surface 21d. The second face 11b is spaced from and disposed face-to-face with the fourth face 21d.

The electrolyte layer 30 is sandwiched between the first electrochromic layer 13 and the second electrochromic layer 23 to constitute an electrochemical cell EC, or the electrochemical cell EC includes the first electrochromic layer 13, the second electrochromic layer 23, and the electrolyte layer 30.

In the optical module 100, by applying a variable voltage to the electrochemical cell EC, the effective refractive index of the second diffraction grating 22 can be changed, so as to dynamically adjust and control the coupling angle of light, and the light absorption coefficient of the electrochemical cell EC can be changed, so as to dynamically adjust and control the light transmittance of the optical module 100.

In the optical module 100 'of the related art, the diffraction grating and the electrochromic layer are designed as separate substrates, but in the optical module 100 of the embodiment of the application, the diffraction grating and the electrochromic layer are integrated into a double-sided design, wherein the first diffraction grating 12 and the first electrochromic layer 13 are independent, the functional layering is not interfered with each other, the first substrate 11 is shared, the second diffraction grating 22 and the second electrochromic layer 23 are independent, the functional layering is not interfered with each other, and the second substrate 21 is shared, so that the problems of large thickness and complex packaging existing in the scheme of externally hanging the electrochromic structure in the traditional optical module 100' are solved, and the optical module 100 is lighter and thinner and has shorter optical path.

Functionally, in the optical module 100' of the related art, the coupling angle of the grating is fixed, the optical path cannot be dynamically adjusted, and the brightness cannot be changed, but in the optical module 100 of the embodiment of the present application, the effective refractive index change of the second diffraction grating 22 and the light absorption coefficient change of the electrochemical cell EC are dynamically controlled by using the voltage input of the electrochemical cell EC, so as to further realize the effects of changing the wavelength or the coupling angle of the optical coupling, improving the optical coupling efficiency, and actively suppressing the stray light, so as to optimize the effects of display uniformity and the like.

In the optical module 100' of the related art, multiple bonding processes are required, and the process is complicated, but the optical module 100 of the embodiment of the application is beneficial to reducing the number of times of alignment because the diffraction grating and the electrochromic layer share the substrate.

In terms of cost, at least four substrates are required in the optical module 100' of the related art, and each substrate is prepared by an independent process, so that the cost is high, but the optical module 100 of the embodiment of the application reduces the number of substrates, reduces the bonding times, simplifies the process, and the like, thereby being beneficial to reducing the material cost and the process cost.

In some embodiments, the first diffraction Grating 12 is a Bragg Grating (Bragg Grating) for light coupling-in and the second diffraction Grating 22 is a sub-wavelength relief Grating (Subwavelength RELIEF GRATING) for light coupling-out.

In the above embodiments, different types or hybrid functional gratings are used, where the bragg grating has high angle selectivity and high wavelength selectivity, and is suitable for coupling in, and the sub-wavelength relief grating (SRG) has high design freedom, and is easy to combine with the electrochromic layer to achieve effective adjustment of the effective refractive index, and is suitable for coupling out.

In some embodiments, the sub-wavelength relief grating has a grating period of 450nm to 900nm, a depth of 50nm to 200nm, and a duty cycle (ratio of trench width to period width) of 0.1 to 0.6. Therefore, the effective refractive index is in the range of 1.6-2.3, and the dynamic regulation and control of the optical coupling angle in the range of 30-60 degrees are facilitated.

In the above embodiment, the specific geometric parameter range (period, depth, duty cycle) of the sub-wavelength relief grating is a preferred interval obtained by simulation according to the coupled wave analysis (Rigorous Coupled-WAVE ANALYSIS, RCWA), which is beneficial to ensuring that the sub-wavelength relief grating can maintain high coupling efficiency when the effective refractive index changes, and realizing high-performance dynamic optical path regulation.

In some embodiments, the first electrochromic layer 13 and the second electrochromic layer 23 form a complementary electrochromic system, the first electrochromic layer 13 includes a first transparent electrode layer 131 and a nickel oxide layer 132 sequentially stacked on the second surface 11b, and the second electrochromic layer 23 includes a second transparent electrode layer 231 and a tungsten oxide layer 232 sequentially stacked on the fourth surface 21 d.

In the above examples, niO (anodic color-changing material) and WO ₃ (cathodic color-changing material) are complementary electrochromic materials that are stable in performance, fast in response speed, and high in optical contrast. The nickel oxide layer 132 and tungsten oxide layer 232 work cooperatively to achieve a large dynamic range of optical properties (effective refractive index and light absorption coefficient) at lower voltages. The nickel oxide layer 132 and the tungsten oxide layer 232 have the advantage of being all solid and low power consumption.

In other embodiments, the first electrochromic layer 13 and the second electrochromic layer 23 may be other materials capable of forming a complementary electrochromic system, one of which is used as an anodic coloring material, and the other of which is used as a cathodic coloring material.

In some embodiments, the optical module 100 includes a visible area 100A and a bezel area 100B adjacent to the visible area 100A. For example, when the optical module 100 is applied to AR glasses, one optical module 100 is provided corresponding to each of the left and right eyes of the user. The frame area 100B surrounds the visible area 100A and is correspondingly mounted at the frame of the AR glasses. The visible area 100A of the optical module 100 is not blocked by the lens frame.

In some embodiments, the first electrochromic layer 13 further comprises a first metal layer 133 and the second electrochromic layer 23 further comprises a second metal layer 233. The first metal layer 133 is located between the first transparent electrode layer 131 and the nickel oxide layer 132, and is located in the frame region 100B. The second metal layer 233 is located between the second transparent electrode layer 231 and the tungsten oxide layer 232 and is located in the frame region 100B.

In some embodiments, the first metal layer 133 is located on a surface of the first transparent electrode layer 131 facing the nickel oxide layer 132, and the second metal layer 233 is located on a surface of the second transparent electrode layer 231 facing the tungsten oxide layer 232.

The first transparent electrode layer 131 and the second transparent electrode layer 231 are typically indium tin oxide, and the first transparent electrode layer 131 and the second transparent electrode layer 231 are not as conductive as metals. The first transparent electrode layer 131 and the second transparent electrode layer 231 have a certain sheet resistance (SHEET RESISTANCE). When the lens size of the AR glasses is large, if the current driving the entire lens to change color is conducted only by the first transparent electrode layer 131 and the second transparent electrode layer 231, the following problems may be caused:

first, the voltage drop is not uniform, and when current flows from the electrode contact at the edge of the lens to the center, the voltage gradually decreases due to the resistance of transparent materials such as indium tin oxide. This results in inconsistent actual voltages experienced by the area closer to the power source and the area farther from the power source (e.g., the center of the lens).

Second, the non-uniform response is that the non-uniform voltage results in a non-uniform chemical reaction rate of the electrochromic layers (nickel oxide and tungsten oxide). Eventually, the color of the lens is uneven visually, and plaques with different color shades from the edge to the center can appear, so that the user experience is affected.

Third, the response speed is slow, because the resistance of transparent materials such as indium tin oxide is large, the whole large-area capacitor structure needs longer time to charge/discharge, thereby reducing the switching speed of the glasses from transparent state to colored state (or vice versa).

In the embodiment of the present application, by introducing the first metal layer 133 and the second metal layer 233 (such as copper, silver, aluminum, etc.) having better conductivity than the materials (such as indium tin oxide) of the first transparent electrode layer 131 and the second transparent electrode layer 231, a low-resistance current path can be constructed, so that the current is rapidly transferred to each edge of the lens through the first metal layer 133 and the second metal layer 233, and then applied to the electrochromic layer (nickel oxide layer and tungsten oxide layer) along the thickness direction Z of the optical module 100 through the first transparent electrode layer 131 and the second transparent electrode layer 231. This is advantageous in reducing the voltage drop and ensuring that the voltage across the viewable area 100A is substantially uniform, thereby facilitating a rapid, uniform color change effect.

In addition, since the metal is opaque, if the metal layer is disposed corresponding to the visible area 100A, the user's vision is blocked. The lenses of AR spectacles are typically held by a frame. The rim area 100B is an area where the lens is blocked by the frame and the user's vision cannot pass through. The opaque but electrically conductive first and second metal layers 133 and 233 are disposed in this "hidden" region to serve the key function of optimizing electrical performance without affecting the light transmittance and clarity of the central viewable area 100B at all.

Therefore, the first metal layer 133 and the second metal layer 233 are skillfully hidden in the frame area 100B, which is beneficial to solve the problem of insufficient conductivity of the first transparent electrode layer 131 and the second transparent electrode layer 231, so as to ensure that the electrochromic function of the AR glasses can respond quickly and uniformly, and the transparency of the visible area 100A is not sacrificed.

In some embodiments, the materials of the first substrate 11 and the second substrate 21 are each selected from at least one of rigid glass, ultra-thin flexible glass (Ultra THIN GLASS, UTG), or plastic.

In the above embodiment, the materials of the first substrate 11 and the second substrate 21 cover various options such as rigidity (glass), low cost (plastic) and flexibility (UTG), so as to enhance the applicable scene (such as curved display) of the optical module 100.

In the embodiment of the application, the ultrathin flexible glass refers to a glass material with a thickness of less than or equal to 100 micrometers.

In some embodiments, the optical module 100 further includes an outer lens 40. The outer lens 40 is disposed on the side of the first functional substrate 10 where the first diffraction grating 12 is located. The outer lens 40 has at least one of the following features that it has a diopter adjustment function, has a multilayer film structure on the surface, and has an antireflection film and/or an anti-fingerprint film on the surface, and is subjected to a yellowing-suppressing treatment.

In the above embodiment, the arrangement of the outer lens 40 enables the optical module 100 to combine with the vision correction function, and improves the durability and optical quality (e.g., anti-reflection, anti-fouling) of the final optical module 100.

In some embodiments, the optical module 100 further includes a lamination adhesive layer 50. The outer lens 40 is bonded to the first surface 11a of the first substrate 11 through the adhesive layer 50. The laminating adhesive layer 50 may be, but is not limited to, optically clear adhesive.

In some embodiments, the optical module 100 is applied to AR glasses, the second functional substrate 20 faces the eyes E of the user, and external ambient light is incident from the side of the outer lens 40.

The following describes how the optical module 100 according to the embodiment of the present application can dynamically modulate optical characteristics by applying a voltage, including but not limited to controlling the coupling angle or coupling efficiency of light by electrically controlling the effective refractive index of the second diffraction grating 22, and suppressing stray light or adjusting the overall light transmittance by electrically controlling the light absorption coefficient of the electrochromic layer.

According to the principle of optical absorption by Beer-Lambert Beer's law, there is the following formula (1):

Equation (1).

In the formula (1), η (V, λ) is the optical coupling efficiency of the wavelength λ under the control of the voltage V, η ₀ (λ) is the reference optical coupling efficiency when no voltage is applied, k (V, λ) is the optical absorption coefficient of the wavelength λ under the control of the voltage V, which affects the loss of stray light, and L is the effective propagation wavelength of light in the electrochromic layer.

As is clear from the formula (1), when the voltage V is applied to increase the light absorption coefficient k, the index term is rapidly decreased, and the final optical coupling efficiency η (V, λ) is also decreased accordingly, and the corresponding optical module is darkened, whereas when the voltage V is applied to decrease the light absorption coefficient k, the index term is rapidly increased, and the final optical coupling efficiency η (V, λ) is also increased accordingly, and the corresponding optical module is brightened.

Therefore, as can be seen from the formula (1) and fig. 3, η ₀ (λ) =1, the light absorption coefficient k can be changed in the range of 0 to 0.2 by voltage control, and the corresponding light coupling efficiency η can be changed in the range of 100% to 0%, so as to adjust the display brightness of the optical module, so as to suppress the stray light inside and outside, and improve the display contrast ratio. For example, when k=0, η=100% corresponds to the transparent state of the electrochemical cell, and when k=0.2, η corresponds to the colored state of the electrochemical cell, the optical coupling efficiency is reduced.

According to waveguide mode theory, there is the following formula (2):

Equation (2).

In the formula (2), n _eff (V, lambda) is the effective refractive index of the waveguide or the diffraction grating to the wavelength lambda under the control of the voltage V, the coupling condition is dynamically adjusted, gamma is the overlapping factor of the electrochromic layer to the waveguide mode, and delta n (V, lambda) is the variation amplitude of the refractive index of the material to the light with the wavelength lambda, which is regulated and controlled by the voltage V.

From equation (2), it is known that by applying the voltage V, the refractive index Δn (V, λ) can be changed to linearly change the effective refractive index n _eff.

As can be seen from the combination of equation (2) and fig. 4, when Δn (V, λ) = +0.3, the effective refractive index n _eff is raised to 2.3 corresponding to the transparent state of the electrochemical cell, and when Δn (V, λ) = -0.3, the effective refractive index n _eff is raised to 1.7 corresponding to the colored state of the electrochemical cell.

According to the grating coupling formula, there is the following formula (3):

Equation (3).

In formula (3), n _eff is the effective refractive index, n ₀ is the air refractive index, n ₀ is assumed to be 1, θ is the coupling angle, m is the grating order, typically m= ±1, λ is the coupling wavelength, and Λ is the grating period.

From equation (3), if n ₀, λ, Λ, m are fixed. When the effective refractive index n _eff is changed, the coupling angle θ is changed. As can be seen from the formula (2), the change of the voltage V causes the change of the effective refractive index n _eff, so that the coupling angle θ can be dynamically controlled under a fixed incident wavelength by combining the formula (2) and the formula (3).

The first table shows the relationship among the state, voltage, effective refractive index, coupling angle, and light absorption coefficient at 940 nm.

List one

As can be seen from the reference formula (3), fig. 5 and the table, taking the SRG grating period of 700nm as an example, when the colored state (n _eff =1.7, the voltage is-2V) is changed to the transparent state (n _eff =2.1, the voltage is +2v), the coupling angle is changed from 15 ° to approximately 45 °, which represents that when the voltage is changed in the range of-2V to 2V, the dynamic change range of the coupling angle is approximately 30 °.

Fig. 6 is a simulation result of RCWA, in which yellow regions represent regions of higher coupling efficiency.

The grating depth corresponding to the graph (a) in fig. 6 is 100nm, the grating depth corresponding to the graph (b) in fig. 6 is 130nm, and the grating depth corresponding to the graph (c) in fig. 6 is 160nm.

As is clear from fig. 6 (a), when the grating depth is 100nm, the region having a relatively high coupling efficiency corresponds to a region having a grating period of 680nm to 720nm and a duty cycle of 0.5 to 0.6, and the optical coupling efficiency is 67.5% at the maximum.

As is clear from fig. 6 (b), when the grating depth is 130nm, the region corresponding to the high coupling efficiency is approximately 680nm to 730nm, and the optical coupling efficiency is 96% at the maximum in the region having the duty ratio of 0.55±0.05.

As is clear from fig. 6 (c), when the grating depth is 160nm, the region having a relatively high coupling efficiency corresponds to a region having a grating period of 650nm to 750nm and a duty cycle of 0.5 to 0.6, and the optical coupling efficiency is 67.5% at the maximum.

The embodiment of the application also provides a preparation method of the optical module. The preparation method of the optical module comprises the following steps S10 and S30. The order of certain steps or sub-steps of the method of manufacturing an optical module may be changed, and certain steps or sub-steps may be omitted or combined according to different needs. In addition, the optical module set of any one of the above embodiments is manufactured by the method. The method of manufacturing the optical module can be understood as follows with reference to fig. 2.

Step S10, providing a first functional substrate, wherein the first functional substrate is integrated with a first diffraction grating and a first electrochromic layer.

In some embodiments, step S10 includes forming a first diffraction grating 12 on a first side 11a of the first substrate 11, forming a first electrochromic layer 13 on a second side 11b of the first substrate 11, the first side 11a being opposite the second side 11 b.

In some embodiments, the first diffraction grating 12 may be formed by, but not limited to, nanoimprinting or etching.

In some embodiments, the first electrochromic layer 13 may be formed by, but not limited to, plating.

In the step S10, since the first diffraction grating 12 and the first electrochromic layer 13 are integrated in the first functional substrate 10, compared with the manner of aligning and bonding different substrates after the first diffraction grating and the first electrochromic layer are respectively formed on different substrates, the number of substrates and the times of aligning and bonding are reduced, which is beneficial to improving the yield and efficiency of the process and reducing the manufacturing cost.

Step S20, providing a second functional substrate, wherein the second functional substrate is integrated with a second diffraction grating and a second electrochromic layer.

In some embodiments, referring to fig. 2 in combination, step S20 includes forming a second diffraction grating 22 on a third surface 21c of the second substrate 21, forming a second electrochromic layer 23 on a fourth surface 21d of the second substrate 21, the fourth surface 21d being opposite to the third surface 21 c.

In some embodiments, the second diffraction grating 22 may be formed by, but not limited to, nanoimprinting or etching.

In some embodiments, the second electrochromic layer 23 may be formed by, but not limited to, plating.

In the step S20, since the second diffraction grating 22 and the second electrochromic layer 23 are integrated in the second functional substrate 20, compared with the manner of aligning and bonding different substrates after the second diffraction grating and the second electrochromic layer are respectively formed on different substrates, the number of substrates and the times of aligning and bonding are reduced, which is beneficial to improving the yield and efficiency of the process and reducing the manufacturing cost.

Step S30, assembling the first functional substrate and the second functional substrate through an alignment and lamination process, and forming an electrolyte layer between the first functional substrate and the second functional substrate to form an electrochemical unit.

In some embodiments, referring to FIG. 2, step S30 includes disposing the second surface 11b of the first substrate 11 and the fourth surface 21d of the second substrate 21 in a spaced-apart and face-to-face arrangement by an alignment and lamination process, and then forming the electrolyte layer 30 between the first electrochromic layer 13 and the second electrochromic layer 23.

In the method for manufacturing an optical module, in the step S10, the first diffraction grating and the first electrochromic layer share the first substrate, and in the step S20, the second diffraction grating and the second electrochromic layer share the second substrate, so that the optical module can be formed by a single alignment and lamination process. Therefore, the traditional preparation method of the optical module is simplified into one step through multi-step alignment lamination, the process flow is greatly simplified, the production yield and efficiency are improved, and the manufacturing cost is reduced.

In some embodiments, the method further includes attaching an external lens to a side of the first diffraction grating of the first functional substrate. In this case, the number of substrates in the optical module is not more than three (the first substrate, the second substrate and the outer lens), and the bonding process between the two substrates is not more than two times (the first functional substrate is bonded once with the second functional substrate, and the outer lens is bonded once with the first functional substrate). Compared with the optical module 100' shown in fig. 1, the thickness of the two layers of substrates and the thickness of the two layers of bonding glue are reduced, and the twice assembling and bonding processes are reduced, so that the thickness of the optical module is reduced, the production flow is simplified, and the preparation cost is reduced.

The embodiment of the application also provides an optical system. The optical system includes the optical module and the control unit (not shown) of any of the above embodiments. The control unit is electrically connected with the electrochemical unit and is configured to send a variable voltage to the electrochemical unit to cooperatively regulate the effective refractive index and the light absorption coefficient.

In some embodiments, as shown in fig. 7, the optical system 1000 is AR glasses. The AR glasses include the optical module 100 and the lens frame 200 according to any of the above embodiments. The number of the optical modules 100 is two. The two optical modules 100 are mounted on a frame 200. When the user wears the AR glasses, the left and right eyes of the user correspond to one optical module 100, respectively.

Referring to fig. 2 and fig. 7 in combination, the visible area 100A of the optical module 100 is exposed at the frame 200, and the bezel area 100B is correspondingly mounted to the frame 200. After the user wears the AR glasses, the second functional substrate 20 is closer to the user's eyes E than the first functional substrate 10.

In some embodiments, the optical system is an augmented reality or virtual reality display system, the optical system further includes an image source, and the optical module is disposed on an optical path of the image source, for coupling and guiding image light emitted from the image source to eyes of an observer, and adjusting transmittance of ambient light in the optical module.

In some embodiments, the optical system is a Time-of-Flight (ToF) system or a Light Detection and ranging (LiDAR) system (also known as an optical radar system), and the optical system further comprises a Light source and a sensor, and the optical module is disposed in an outgoing Light path of the Light source and/or an incoming Light path of the sensor, and is configured to perform an angular scan on a Light beam emitted by the Light source and/or adjust a Light intensity entering the sensor. The light source may be, but is not limited to, a laser light source.

In some embodiments, the optical system is an adjustable optical filter, and the control unit is configured to adjust the variable voltage, so that the optical module selectively diffracts the light with a specific wavelength or an incident angle, and adjust the overall intensity of the light transmitted through the optical module.

In some embodiments, the optical system is a smart window or a light-adjusting glass, and the optical module forms at least one part of the smart window or the light-adjusting glass, for controlling the transmittance of the ambient light penetrating the at least one part, and/or changing the propagation direction of the light penetrating the at least one part.

In some embodiments, in smart windows or dimming glasses, the light transmittance of the glass can be adjusted in a large area by utilizing the dynamic adjustment and control of the light absorption coefficient k, so that energy conservation and privacy protection are realized.

The above embodiments are only for illustrating the technical solution of the present application and not for limiting the same, and although the present application has been described in detail with reference to the above preferred embodiments, it should be understood by those skilled in the art that modifications and equivalents may be made thereto without departing from the spirit and scope of the technical solution of the present application.

Claims (10)

1. An optical module, comprising:

The first functional substrate comprises a first substrate, a first diffraction grating formed on a first surface of the first substrate and a first electrochromic layer formed on a second surface of the first substrate, wherein the first surface is opposite to the second surface;

A second functional substrate including a second substrate, a second diffraction grating formed on a third surface of the second substrate, the third surface being opposite to the fourth surface, the second surface being spaced apart from the fourth surface and arranged face to face, and a second electrochromic layer formed on a fourth surface of the second substrate, and

An electrolyte layer sandwiched between the first electrochromic layer and the second electrochromic layer to form an electrochemical cell;

The effective refractive index of the second diffraction grating and the light absorption coefficient of the electrochemical unit can be changed by applying a variable voltage to the electrochemical unit, so that the coupling angle and the light transmittance of the optical module can be dynamically regulated.

2. The optical module of claim 1 wherein the first diffraction grating is a bragg grating for light coupling in and the second diffraction grating is a sub-wavelength relief grating for light coupling out.

3. The optical module of claim 2, wherein the sub-wavelength relief grating has a grating period of 450nm to 900nm, a depth of 50nm to 200nm, and a duty cycle of 0.1 to 0.6.

4. The optical module of claim 1, wherein the first electrochromic layer and the second electrochromic layer form a complementary electrochromic system, the first electrochromic layer comprising a nickel oxide layer, the second electrochromic layer comprising a tungsten oxide layer.

5. The optical module of claim 1, wherein the materials of the first substrate and the second substrate are each selected from at least one of rigid glass, ultra-thin flexible glass, or plastic.

6. The optical module of any one of claims 1 to 5, further comprising an outer lens disposed on a side of the first functional substrate where the first diffraction grating is located, the outer lens having at least one of the following features:

the diopter adjusting function is provided;

The surface has a multilayer film structure comprising an anti-reflection film and/or an anti-fingerprint film;

Through yellowing inhibition treatment.

7. A method of manufacturing an optical module, comprising:

Providing a first functional substrate, wherein the first functional substrate is integrated with a first diffraction grating and a first electrochromic layer;

Providing a second functional substrate integrated with a second diffraction grating and a second electrochromic layer, and

And assembling the first functional substrate and the second functional substrate through an alignment and lamination process, and forming an electrolyte layer between the first functional substrate and the second functional substrate to form an electrochemical unit.

8. The method for manufacturing an optical module according to claim 7, it is characterized in that the method comprises the steps of,

The first functional substrate comprises a first diffraction grating formed on a first surface of the first substrate, and a first electrochromic layer formed on a second surface of the first substrate, wherein the first surface is opposite to the second surface;

Forming the second diffraction grating on a third surface of a second substrate, forming the second electrochromic layer on a fourth surface of the second substrate, the third surface being opposite to the fourth surface;

Assembling the first functional substrate with the second functional substrate includes disposing the second face of the first substrate and the fourth face of the second substrate in a spaced-apart and face-to-face relationship and forming the electrolyte layer between the first electrochromic layer and the second electrochromic layer.

9. An optical system, comprising:

the optical module according to claim 1 to 6, and

And the control unit is electrically connected with the electrochemical unit and is configured to send the variable voltage to the electrochemical unit so as to cooperatively regulate and control the effective refractive index and the light absorption coefficient.

10. The optical system of claim 9, wherein,

The optical system is an augmented reality or virtual reality display system, the optical system further comprises an image source, the optical module is arranged on a light path of the image source and used for coupling and guiding image light emitted by the image source to eyes of an observer and adjusting the transmissivity of ambient light in the optical module;

Or alternatively

The optical system is a time-of-flight system or an optical radar system, the optical system further comprises a light source and a sensor, and the optical module is arranged in an emergent light path of the light source and/or an incident light path of the sensor and is used for carrying out angle scanning on a light beam emitted by the light source and/or adjusting the light intensity entering the sensor;

Or alternatively

The optical system is an adjustable optical filter, and the control unit is configured to enable the optical module to selectively diffract light rays with specific wavelengths or incidence angles by adjusting and controlling the variable voltage, and adjust the overall intensity of the light rays transmitted through the optical module;

Or alternatively

The optical system is a light-adjusting glass, and the optical module forms at least one part of the light-adjusting glass and is used for controlling the light transmittance of the ambient light penetrating through the at least one part and/or changing the propagation direction of the light penetrating through the at least one part.