Flat lens, preparation method thereof and electronic device

Abstract

The embodiment of the invention relates to the technical field of display, and provides a flat lens, a preparation method of the flat lens and an electronic device. The flat lens comprises a light-transmitting first substrate, an anti-fake layer located on the surface of the first substrate and an optical waveguide layer attached to the side, away from the first substrate, of the anti-fake layer. The anti-counterfeiting layer comprises a high-refractive-index layer and a low-refractive-index layer which are alternately stacked, the refractive index of the high-refractive-index layer is larger than that of the low-refractive-index layer, and the anti-counterfeiting layer allows visible light to penetrate but does not allow ultraviolet light to penetrate. The optical waveguide comprises a plurality of first reflection units and a plurality of second reflection units, each first reflection unit extends in the first direction, each second reflection unit extends in the second direction, the first reflection units and the second reflection units are arranged in an orthogonal mode in the third direction, and every two of the first direction, the second direction and the third direction are perpendicular to each other. The flat lens has an anti-counterfeiting function.

Description

Technical Field

[0001] This application relates to the field of display technology. Specifically, it relates to a flat lens, a preparation method thereof, and an electronic device. Background Art

[0002] At present, interactive aerial imaging technology is applied in various fields. As the core component of this technology, there are various counterfeit equivalent negative refractive flat lenses on the market. Therefore, it is necessary to provide an equivalent negative refractive flat lens with an anti-counterfeiting function. Summary of the Invention

[0003] In a first aspect of this application, a flat lens is provided. The flat lens includes:

[0004] A light-transmitting first substrate;

[0005] An anti-counterfeiting layer located on the surface of the first substrate. The anti-counterfeiting layer includes alternately stacked high-refractive-index layers and low-refractive-index layers. The refractive index of the high-refractive-index layer is greater than that of the low-refractive-index layer. The anti-counterfeiting layer allows visible light to pass through but does not allow ultraviolet light to pass through; and

[0006] An optical waveguide layer attached to the side of the anti-counterfeiting layer away from the first substrate. The optical waveguide includes a plurality of first reflection units and a plurality of second reflection units. Each first reflection unit extends in a first direction, and each second reflection unit extends in a second direction. In a third direction, the first reflection units and the second reflection units are orthogonally arranged, and the first direction, the second direction, and the third direction are perpendicular to each other in pairs.

[0007] The flat lens in the first aspect of this application includes an anti-counterfeiting layer that allows visible light to pass through but does not allow ultraviolet light to pass through. Thus, on the one hand, the anti-counterfeiting layer allows visible light to pass through without affecting the imaging of the flat lens itself. On the other hand, the anti-counterfeiting layer does not allow ultraviolet light to pass through. When it is necessary to conduct an anti-counterfeiting inspection on the flat lens, an ultraviolet light source is placed on one side of the flat lens, and an ultraviolet test card is placed on the other side. The surface of the ultraviolet test card is coated with a layer of ultraviolet-sensitive fluorescent material. When ultraviolet light irradiates the ultraviolet test card, the fluorescent material will fluoresce to generate the brightness of visible light. The brightness of this visible light is proportional to the radiation intensity of ultraviolet light. Since the ultraviolet light emitted by the ultraviolet light source cannot pass through the anti-counterfeiting layer in the flat lens, the ultraviolet test card does not receive ultraviolet light at the position corresponding to the anti-counterfeiting layer. Therefore, the area corresponding to the anti-counterfeiting layer on the ultraviolet test card will not emit visible light, while the other areas on the ultraviolet test card will emit visible light, thereby presenting the information of the anti-counterfeiting layer and further realizing the anti-counterfeiting function.

[0008] In a second aspect of this application, a preparation method of a flat lens is provided. The preparation method of the flat lens includes:

[0009] A security layer is formed on the surface of a light-transmissive first substrate. The security layer includes alternately stacked high-refractive-index layers and low-refractive-index layers. The refractive index of the high-refractive-index layer is greater than that of the low-refractive-index layer. The security layer allows visible light to pass through but does not allow ultraviolet light to pass through; and

[0010] The optical waveguide layer is bonded to the side of the first substrate where the security layer is formed. The optical waveguide includes a plurality of first reflection units and a plurality of second reflection units. Each of the first reflection units extends in a first direction, and each of the second reflection units extends in a second direction. In a third direction, the first reflection units and the second reflection units are orthogonally arranged, and the first direction, the second direction, and the third direction are perpendicular to each other pairwise.

[0011] A third aspect of the present application provides an electronic device. The electronic device includes:

[0012] A display for emitting image light; and

[0013] The flat lens according to the first aspect of the present application, located on one side of the display;

[0014] Wherein, the flat lens is used to converge the image light to form a floating real image on the side of the flat lens away from the display.

[0015] The electronic device according to the third aspect of the present application has the same advantages as the flat lens according to the first aspect of the present application, and will not be elaborated herein. Description of the Drawings

[0016] Figure 1 It is a schematic structural diagram of the electronic device according to the first embodiment of the present application.

[0017] Figure 2 It is a schematic structural diagram of the optical display module according to an embodiment of the present application.

[0018] Figure 3 It is a side view of the flat lens according to an embodiment of the present application.

[0019] Figure 4 It is a schematic diagram of the mask plate for forming the security layer of the flat lens according to an embodiment of the present application.

[0020] Figure 5 It is a schematic diagram of the reflectivity of the security layer according to an embodiment of the present application at different wavelengths.

[0021] Figure 6 It is a schematic structural diagram for anti-counterfeiting inspection of the flat lens according to an embodiment of the present application.

[0022] Figure 7Schematic diagram of the anti-counterfeiting layer according to an embodiment of the present application.

[0023] Figure 8 Stereogram of the flat lens according to an embodiment of the present application.

[0024] Figure 9 Schematic diagram of the structures of the first optical waveguide array and the second optical waveguide array in the flat lens according to an embodiment of the present application.

[0025] Figure 10 Planar schematic diagram of the first optical waveguide array and the second optical waveguide array in the flat lens according to an embodiment of the present application.

[0026] Figure 11 Schematic diagram of the structures of the first reflection unit and the second reflection unit in the flat lens according to an embodiment of the present application.

[0027] Figure 12 Schematic diagram of the imaging principle of the flat lens according to an embodiment of the present application.

[0028] Figure 13 Schematic diagram of the structure of the electronic device according to the second embodiment of the present application.

[0029] Figure 14 Flowchart of the preparation method of the flat lens according to an embodiment of the present application.

[0030] Description of the main component symbols:

[0031] Electronic device 100

[0032] Optical display modules 110, 110’

[0033] Imaging modules 110a, 110a’

[0034] Flat lens 10

[0035] First substrate 11

[0036] Anti-counterfeiting layer 12

[0037] High refractive index layer 12H

[0038] Low refractive index layer 12L

[0039] Optical waveguide layer 13

[0040] First optical waveguide array 131

[0041] First reflection unit 131a

[0042] Second optical waveguide array 132

[0043] Second reflection unit 132a

[0044] Reflection film 133

[0045] Second substrate 14

[0046] Adhesive 15

[0047] Display 20

[0048] Total reflection mirror 30

[0049] Detection module 110b

[0050] Control module 110c

[0051] Main control system 120

[0052] Mask plate 200

[0053] Ultraviolet light source 300

[0054] Ultraviolet test card 400

[0055] Pattern P

[0056] Floating real image E

[0057] Virtual image V

[0058] First direction X

[0059] Second direction Y

[0060] Third direction Z

[0061] Image light L Detailed implementation manners [[ID=�6]]

[0062] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments.

[0063] Such as Figure 1As shown, the electronic device 100 includes an optical display module 110 and a main control system 120 electrically connected to the optical display module 110. The optical display module 110 includes an imaging module 110a, a detection module 110b, and a control module 110c. The imaging module 110a is configured to image and display the screen of the optical display module 110 in the air. The detection module 110b can detect the user's interaction operation to generate interaction information and transmit the interaction information to the control module 110c. The control module 110c determines the specific operation content of the user according to the internal instruction set and the interaction information, generates a corresponding control signal, and sends the control signal to the main control system 120. The main control system 120 can control the electronic device 100 to complete various operations according to the control signal. At the same time, the control module 110c transmits the operation interface or control result corresponding to the control signal to the imaging module 110a, and the imaging module 110a displays the image in the air to facilitate the user's next operation or to know the control result.

[0064] As Figure 2 shown, the imaging module 110a includes a flat lens 10 and a display 20. The display 20 is disposed on one side of the flat lens 10. The display 20 is configured to emit image light L. The flat lens 10 is configured to converge the image light L to form a floating real image E opposite to the display 20 on the side of the flat lens 10 away from the display 20. The detection module 110b is configured to detect the operation of the user on the floating real image E and feedback the detected interaction signal to the control module 110c. Specifically, the optical display module 110 can present the status information of the electronic device 100 and information such as operation buttons displayed on the display 20 on the floating real image E. The user can understand the current status of the electronic device 100 through the floating real image E and control the electronic device 100 by clicking on the virtual button of the floating real image E.

[0065] In some embodiments, the electronic device 100 can be a household appliance (such as a refrigerator, a washing machine, a dishwasher, etc.), a self-service terminal (such as a medical self-service machine, a bank self-service machine, etc.), or other devices with a display 20 (such as a head-mounted display device). The user can perform operations such as clicking and swiping on the floating real image E to improve the user experience.

[0066] In some embodiments, the display 20 can be a Light Emitting Diode (LED) display, a Liquid Crystal Display (LCD), a Liquid Crystal on Silicon (LCoS) device, an Organic Light-Emitting Diode (OLED) display, a projection, a laser, a laser diode, or any other suitable display or a stereoscopic display, and is not limited thereto.

[0067] In some embodiments, the brightness of the display 20 can be set to not less than 500 cd / m 2 , so as to reduce the influence caused by brightness loss during the optical path propagation. Of course, in actual applications, the display brightness of the display 20 can be adjusted according to the brightness of the ambient light.

[0068] In some embodiments, performing a viewing angle control process on the surface of the display image of the display 20 can reduce the afterimage of the floating virtual image E, improve the picture quality, and also prevent others from peeping, so it can be widely applied to other input devices that require privacy information protection.

[0069] In some embodiments, the detection module 110b can be a far and near infrared sensor, an ultrasonic sensor, a laser interference sensor, a grating sensor, an encoder, a fiber optic sensor, or a charge-coupled device (CCD) sensor. That is to say, the sensing forms of the detection module 110b include but are not limited to far and near infrared, ultrasonic, laser interference, grating, encoder, fiber optic, or CCD (charge-coupled device), etc. The sensing area of the detection module 110b is in the same plane as the floating virtual image E and includes the three-dimensional space where the floating virtual image E is located. The best sensing form can be selected according to the installation space, viewing angle, and use environment, which is convenient for users to operate the floating virtual image E in the best posture and improves the sensitivity and convenience of user operation.

[0070] In some embodiments, the control module 110c and the imaging module 110a, and the control module 110c and the detection module 110b can be connected in a wired or wireless manner to transmit digital or analog signals, so as to flexibly control the volume of the optical display module 110 and enhance the electrical stability of the optical display module 110.

[0071] Next, the structure of the flat lens 10 in the embodiments of the present application will be described.

[0072] As Figure 3 shown, the flat lens 10 includes a first substrate 11, an anti-counterfeiting layer 12, an optical waveguide layer 13, and a second substrate 14 stacked in sequence. The anti-counterfeiting layer 12 is located on the surface of the first substrate 11 facing the optical waveguide layer 13. The optical waveguide layer 13 includes a first optical waveguide array 131 and a second optical waveguide array 132. The first optical waveguide array 131 is located between the anti-counterfeiting layer 12 and the second optical waveguide array 132. The first optical waveguide array 131 and the second optical waveguide array 132 are closely attached in the same plane.

[0073] Both the first substrate 11 and the second substrate 14 have two optical surfaces. The first substrate 11 and the second substrate 14 have a light transmittance of 90% to 100% for light with a wavelength between 390 nm and 760 nm. The materials of the first substrate 11 and the second substrate 14 can both be glass or plastic (such as acrylic resin) for protecting the optical waveguide layer 13 and filtering out excess light. In other embodiments, if the strength is sufficient after the first optical waveguide array 131 and the second optical waveguide array 132 are closely orthogonally attached, or there are thickness limitations in the installation environment, the second substrate 14 can be omitted.

[0074] The anti-counterfeiting layer 12 is an optical film with a specific pattern. Specifically, the anti-counterfeiting layer 12 can be formed by using a mask plate during the coating process. As Figure 4 shown, the mask plate 200 has a hollowed-out pattern P. The pattern P is text (DCT equivalent negative refractive index flat lens). During the process of forming the anti-counterfeiting layer 12 by coating, the evaporated film material can pass through the hollowed-out pattern P of the mask plate 200 and form on the surface of the first substrate 11. In other embodiments, the pattern P is not limited to text and can also be a graphic or a combination of a graphic and text.

[0075] As Figure 5 shown, the anti-counterfeiting layer 12 exhibits high transmittance (transmittance > 98%) in the visible light band of 400 nm to 700 nm, that is, the setting of the anti-counterfeiting layer 12 does not affect the optical performance of the flat lens 10 itself. In the ultraviolet band of 355 nm to 365 nm, it has a relatively high reflectivity (reflectivity ≥ 80%), making the ultraviolet light unable to pass through the anti-counterfeiting layer 12 of the flat lens 10. Therefore, it can also be said that the anti-counterfeiting layer 12 allows visible light to pass through but does not allow ultraviolet light to pass through.

[0076] As Figure 6 shown, when it is necessary to conduct an anti-counterfeiting inspection on the flat lens 10, an ultraviolet light source 300 is placed on one side of the flat lens 10, and an ultraviolet test card 400 is placed on the other side. The surface of the ultraviolet test card 400 is coated with a layer of ultraviolet-sensitive fluorescent material. When ultraviolet light irradiates on the ultraviolet test card 400, the fluorescent material will fluoresce to generate the brightness of visible light. The brightness of this visible light is proportional to the radiation intensity of the ultraviolet light. Since the ultraviolet light emitted by the ultraviolet light source 300 cannot pass through the anti-counterfeiting layer 12 in the flat lens 10, the ultraviolet test card 400 does not receive ultraviolet light at the position corresponding to the anti-counterfeiting layer 12. Therefore, the area corresponding to the anti-counterfeiting layer 12 on the flat lens 10 on the ultraviolet test card 400 will not emit visible light, while the other areas on the ultraviolet test card 400 will emit visible light, thereby presenting the pattern P of the anti-counterfeiting layer 12.

[0077] As Figure 7As shown, the anti-counterfeiting layer 12 includes alternately stacked high refractive index layers 12H and low refractive index layers 12L. The refractive index of the high refractive index layer 12H is greater than that of the low refractive index layer 12L. By alternately stacking material layers with different refractive indices in the anti-counterfeiting layer 12, and taking advantage of the different reflection and refraction effects of light with different wavelengths at the interfaces between the high refractive index layer 12H and the low refractive index layer 12L, the anti-counterfeiting layer 12 has a high reflectivity to ultraviolet light and a high transmittance to visible light.

[0078] In some embodiments, the refractive index of the high refractive index layer 12H is not less than 1.9 (such as 1.9 to 2.0, 2.0 to 2.4, 2.5 to 2.7), and the refractive index of the low refractive index layer 12L is not greater than 1.55 (such as 1.45 to 1.55, 1.8 to 2), but is not limited thereto. If the refractive index of the high refractive index layer 12H is too high, it is not conducive to the transmission of visible light and affects the transparency of the anti-counterfeiting layer 12. If the refractive index of the low refractive index layer 12L is too low, it may cause insufficient effective interference of ultraviolet light at the interfaces between the high refractive index layer 12H and the low refractive index layer 12L, ultimately being not conducive to the improvement of the reflectivity of ultraviolet light.

[0079] In some embodiments, the thickness range of the high refractive index layer 12H is 15 nm to 224 nm (such as 15 nm to 26 nm, 26 nm to 44 nm, 44 nm to 47 nm, 47 nm to 51 nm, 51 nm to 224 nm), and the thickness range of the low refractive index layer 12L is 32 nm to 229 nm (such as 32 nm to 35 nm, 35 nm to 42 nm, 42 nm to 45 nm, 45 nm to 84 nm, 84 nm to 146 nm, 146 nm to 229 nm), but is not limited thereto. Specifically, if the thickness of the high refractive index layer 12H is too high, it may lead to an excessive enhancement of the reflection of ultraviolet light, while affecting the overall light transmittance of the anti-counterfeiting layer 12 in the visible light range, and may also cause unnecessary optical losses and dispersion effects. If the thickness of the high refractive index layer 12H is too low, it may not be able to effectively reflect ultraviolet light due to the too thin high refractive index layer 12H, or may not be able to produce the required interference effect with the low refractive index layer 12L. If the thickness of the low refractive index layer 12L is too high, it will increase the propagation path of visible light, thereby increasing the scattering and absorption of visible light, and further affecting the overall light transmittance of the anti-counterfeiting layer 12 in the visible light range. If the thickness of the low refractive index layer 12L is too low, it is not sufficient to produce effective interference with the high refractive index layer 12H, and may cause an increase in the transmittance of ultraviolet light.

[0080] In some embodiments, the total number of high refractive index layers 12H and low refractive index layers 12L is not less than 9 layers (such as 9 to 10 layers, 10 to 15 layers, 15 to 30 layers). Specifically, if the total number of high refractive index layers 12H and low refractive index layers 12L is too small, it means that the high refractive index layers 12H and low refractive index layers 12L form a weak interference effect, which may cause ultraviolet light to pass through the anti-counterfeiting layer 12 and fail to achieve the required optical effect. If the total number of high refractive index layers 12H and low refractive index layers 12L is too large, the cost will increase and the preparation will be complex. Moreover, when the total number of high refractive index layers 12H and low refractive index layers 12L reaches a certain number, the performance improvement brought by each additional layer will become smaller and smaller.

[0081] In some embodiments, the material of the high refractive index layer 12H is selected from at least one of titanium dioxide and zinc oxide, and the material of the low refractive index layer 12L is selected from at least one of silicon dioxide and silicon oxynitride. Specifically, both titanium dioxide and zinc oxide have good ultraviolet light reflection ability. Titanium dioxide is more chemically stable than zinc oxide. Zinc oxide has a lower cost than titanium dioxide. Silicon dioxide has stable chemical properties and good transparency in the ultraviolet to infrared band. Its refractive index is lower than that of silicon oxynitride, which can form a contrast with the high refractive index layer 12H and enhance the ultraviolet light reflection ability. In addition, the cost of silicon dioxide is lower than that of silicon oxynitride. Silicon oxynitride is superior to silicon dioxide in mechanical properties and can provide good impact resistance.

[0082] The following takes the material of the high refractive index layer 12H as titanium dioxide, the material of the low refractive index layer 12L as silicon dioxide, and the total number of high refractive index layers 12H and low refractive index layers 12L as 15 layers as an example for illustration. Specifically, when the material of the first substrate 11 is glass, since the bonding force between silicon dioxide and glass is better than that between titanium dioxide and glass, the film layer in the anti-counterfeiting layer 12 that is in direct contact with the first substrate 11 is silicon dioxide. Further, since silicon dioxide has better wear resistance than titanium dioxide, the outermost layer of the anti-counterfeiting layer 12 is also silicon dioxide.

[0083] The following describes the specific structure of the optical waveguide layer 13.

[0084] As Figure 8 shown, the first optical waveguide array 131 includes a plurality of first reflection units 131a with rectangular cross-sections. The second optical waveguide array 132 includes a plurality of second reflection units 132a with rectangular cross-sections.

[0085] As Figure 9As shown, the lengths of the first reflection units 131a are restricted by the outer dimensions of the first optical waveguide array 131, so they are of different lengths. The lengths of the second reflection units 132a are restricted by the outer dimensions of the second optical waveguide array 132, so they are of different lengths. Each first reflection unit 131a extends along the first direction X, and each second reflection unit 132a extends along the second direction Y. When viewed from the third direction Z (i.e., the thickness direction of the optical waveguide layer 13), the extension directions of the first reflection units 131a and the second reflection units 132a are perpendicular to each other. The first direction X, the second direction Y, and the third direction Z are perpendicular to each other pairwise. That is, the first optical waveguide array 131 and the second optical waveguide array 132 are orthogonally arranged, so that two light beams in the orthogonal directions converge at a point, and it is ensured that the object image plane (light source side and imaging side) is symmetric with respect to the flat lens 10, generating an equivalent negative refraction phenomenon and realizing aerial imaging.

[0086] As Figure 10 shown, the first optical waveguide array 131 is composed of first reflection units 131a arranged side by side at an angle θ in the lower left direction and having a rectangular cross-section. The second optical waveguide array 132 can be composed of second reflection units 132a arranged side by side at 45° in the lower right direction and having a rectangular cross-section. The arrangement directions of the reflection units in the two groups of optical waveguide arrays can be interchanged. For example, the extension direction of the reflection units in the first optical waveguide array 131 is the second direction Y, and the extension direction of the reflection units in the second optical waveguide array 132 is the first direction X. The angle θ can be 45°, but is not limited thereto. The optical refractive index of the material of the first optical waveguide array 131 or the second optical waveguide array 132 is greater than 1.4, such as 1.5, 1.8, 2.0, etc.

[0087] As Figure 11 shown, for the first optical waveguide array 131 and the second optical waveguide array 132, there are two interfaces between the first reflection unit 131a and the adjacent second reflection unit 132a, and each interface is joined by an adhesive 15 with good light transmittance. The adhesive 15 can be a photosensitive adhesive or a thermosetting adhesive. The thickness of the adhesive 15 is greater than 0.001 mm (such as 0.002 mm, 0.003 mm, or 0.0015 mm). In addition, adhesives 15 are provided between the first optical waveguide array 131 and the second optical waveguide in the flat lens 10, between the first optical waveguide array 131 and the first substrate 11, and between the second optical waveguide array 132 and the second substrate 14 to increase firmness.

[0088] In some embodiments, the cross-section of the first reflection unit 131a can be rectangular, and a reflection film 133 is disposed along one or both side surfaces of the first reflection unit 131a. Similarly, the cross-section of the second reflection unit 132a can be rectangular, and a reflection film 133 is disposed along one or both side surfaces of the second reflection unit 132a. Specifically, in the thickness direction of the optical waveguide layer 13, reflection films 133 are plated on both sides of each of the first reflection units 131a and both sides of each of the second reflection units 132a. The material of the reflection film 133 can be a metal material such as aluminum or silver that enables total reflection, or other non-metal compound materials. The function of the reflection film 133 is to prevent light from entering the adjacent optical waveguide array due to lack of total reflection and forming stray light, which affects imaging. Alternatively, a dielectric film can be added to the reflection film 133, and the function of the dielectric film is to improve the light reflectivity.

[0089] In some embodiments, the cross-section width and cross-section length of a single first reflection unit 131a and a single second reflection unit 132a both satisfy being greater than or equal to 0.1 mm and less than or equal to 5 mm. Further, in order to obtain a better imaging effect, the cross-section width and cross-section length of a single first reflection unit 131a and a single second reflection unit 132a both satisfy being greater than or equal to 0.1 mm and less than or equal to 2 mm. For example, the cross-section width and cross-section length of a single first reflection unit 131a and a single second reflection unit 132a are both 0.2 mm or both 0.5 mm. When displaying on a large screen, large-size requirements can be achieved by splicing multiple optical waveguide arrays.

[0090] In some embodiments, both the first optical waveguide array 131 and the second optical waveguide array 132 are integrally in a rectangular structure, the reflection units at two diagonals are triangular, and the middle reflection units are in a trapezoidal structure. The lengths of the single reflection units are not equal, the reflection unit located on the diagonal of the rectangle has the longest length, and the reflection units at both ends have the shortest length. In other embodiments, the overall shapes of the first optical waveguide array 131 and the second optical waveguide array 132 are set according to the application scenario requirements.

[0091] In some embodiments, the flat lens 10 may further include an anti-reflection component (not shown in the figure) and a viewing angle control component (not shown in the figure). The anti-reflection component can improve the overall transmittance of the flat lens 10 and enhance the clarity and brightness of the floating real image E. The viewing angle control component can be used to eliminate the afterimage of the floating real image E, reduce the dizziness of the observer, and at the same time prevent the observer from peeping into the interior of the device from other angles, improving the overall aesthetics of the electronic device 100. Among them, the anti-reflection component and the viewing angle control component can be combined, or can also be separately and independently disposed between the first substrate 11 and the first waveguide array, between the first waveguide array and the second waveguide array, between the second waveguide array and the second substrate 14, or on the outer layers of the first substrate 11 and the second substrate 14.

[0092] The aerial imaging principle of the flat lens 10 will be described below.

[0093] On the micron scale, a double-layer waveguide array structure that is mutually orthogonal is used to perform orthogonal decomposition on any optical signal. The original signal is projected onto the first optical waveguide array 131. Taking the projection point of the original signal as the origin and the direction perpendicular to the first optical waveguide array 131 as the x-axis, a rectangular coordinate system is established. In this rectangular coordinate system, the original signal is decomposed into two mutually orthogonal signals: the signal X located on the x-axis and the signal Y located on the y-axis. Among them, when the signal X passes through the first optical waveguide array 131, it undergoes total reflection on the surface of the reflection film 133 at a reflection angle equal to the incident angle. At this time, the signal Y remains parallel to the first optical waveguide array 131. After passing through the first optical waveguide array 131, it undergoes total reflection on the surface of the reflection film 133 at a reflection angle equal to the incident angle. The reflected optical signal formed by the reflected signal Y and the signal X is mirror-symmetric with the original optical signal. Therefore, light rays in any direction can achieve mirror symmetry after passing through this flat lens 10. The divergent light from any light source will re-converge into a floating real image E at the symmetric position after passing through this flat lens 10. The imaging distance of the floating real image E is the same as the distance between the flat lens 10 and the image source, i.e., the display 20, which is an equidistant imaging. Moreover, the position of the floating real image E is in the air and does not require a specific carrier, but directly presents a real image in the air. Therefore, the image seen by the user in the space is the image emitted by the display 20. When the light rays emitted by the display 20 pass through the flat lens 10, the above process occurs on the flat lens 10.

[0094] Specifically, as Figure 12 shown, the incident angles of the image light L emitted by the display 20 on the first optical waveguide array 131 are α1, α2, and α3 respectively, and the reflection angles of the light rays on the first optical waveguide array 131 are β1, β2, and β3 respectively, where α1 = β1, α2 = β2, α3 = β3. After being reflected by the first optical waveguide array 131, the incident angles on the second optical waveguide array 132 are γ1, γ2, and γ3 respectively, and the reflection angles on the second optical waveguide array 132 are δ1, δ2, and δ3 respectively, where γ1 = δ1, γ2 = δ2, γ3 = δ3.

[0095] Furthermore, the incident angles after converging to form an image are α1, α2, α3... αn respectively. The distance between the light source of the display 20 and the flat lens 10 is D. Then, the imaging position of the floating real image E is also D away from the flat lens 10, and the viewing angle of the floating real image E is 2 times max(α).

[0096] It can be understood that if the size of the optical waveguide array is small, the image can only be seen at a certain distance from the imaging side of the optical waveguide array; while if the size of the optical waveguide array becomes larger, a larger imaging distance can be achieved, thereby increasing the viewing rate.

[0097] In some embodiments, the included angle between the flat lens 10 and the display 20 is set within the range of 45° ± 5°, so as to effectively utilize the size of the flat lens 10, improve the imaging quality and reduce the influence of afterimage. In addition, if there are other requirements for the imaging position, other angles can also be selected at the expense of some imaging quality. In some embodiments, the size of the flat lens 10 is set to be able to display the floating real image E presented by the entire display 20. However, if only a part of the display screen of the display 20 needs to be seen during actual use, the size and position of the flat lens 10 can also be freely adjusted according to the actual display screen, and no limitation is imposed thereon.

[0098] The above mainly describes the imaging principle of the flat lens 10 adopting a double-layer optical waveguide array structure. In some other embodiments, if the surrounding surfaces are all provided with a plurality of cubic columnar reflection units attached with a reflective film 133, and the plurality of cubic columnar reflection units are arranged in an array along the first direction X and the second direction Y in a single-layer optical waveguide array structure, that is, the two-layer optical waveguide array is combined into one layer, its imaging principle is the same as that of the double-layer optical waveguide array structure, and it can also be used as the structure of the flat lens 10.

[0099] In some embodiments, the thicknesses of the first optical waveguide array 131 and the second optical waveguide array 132 are the same, so as to simplify the complexity of the structures of the first optical waveguide array 131 and the second optical waveguide array 132, reduce the manufacturing difficulty of the first optical waveguide array 131 and the second optical waveguide array 132, improve the production efficiency of the first optical waveguide array 131 and the second optical waveguide array 132, and reduce the production cost of the first optical waveguide array 131 and the second optical waveguide array 132. It should be noted that the same thickness here is a relative range, not absolutely the same, that is, for the purpose of improving production efficiency, a certain thickness difference can exist between the optical waveguide arrays on the premise of not affecting the aerial imaging quality.

[0100] The following refers to the attached Figure 13 Describe the electronic device of the second embodiment of the present application. Except that the structure of the optical display module 110' is different, the rest of the configurations are the same as those of the first embodiment, so the repeated description of the same configurations with the same symbols will be omitted.

[0101] The feature of the structure of the optical display module 110' is that a total reflection mirror 30 is added on the side of the flat lens 10 where the display 20 is located in the imaging module 110a'. The image light L emitted by the display 20 first passes through the reflection of the total reflection mirror 30, and then enters the flat lens 10, and finally converges on the other side of the flat lens 10, thereby forming a floating real image E. The functions and structures of the detection module 110b and the control module 110c are the same as those of the first embodiment.

[0102] It can be seen that after the image light L of the display 20 is reflected by the total reflection mirror 30, an equivalent virtual image V that is the same size as the display 20 and is face-symmetric with respect to the total reflection mirror 30 is formed on the other side of the total reflection mirror 30. The floating real image E is actually mirror-symmetric with respect to the virtual image V with respect to the flat lens 10.

[0103] In some embodiments, the angle between the flat lens 10 and the virtual image V is set in the range of 45° ± 5°, which can make more full use of the size of the flat lens 10, while obtaining better imaging quality and less influence of residual images. However, if there are other requirements for the imaging position, other angles can also be selected at the expense of some imaging quality. Similarly, in some embodiments, the sizes of the flat lens 10 and the total reflection mirror 30 are set such that the user can clearly see the entire floating real image E presented by the display 20 at a glance. However, if only a part of the content of the display 20 needs to be seen during actual use, the size of the flat lens 10 can also be freely adjusted in size and position according to the actual display screen.

[0104] The effect of this embodiment is that it can change the orientation of the display screen in the display 20, and the display 20 can be set closer to the flat lens 10. Without changing the distance between the floating real image E and the flat lens 10, the overall thickness of the optical display module 110' can be significantly reduced, so that it can be better integrated into the electronic device.

[0105] It can be understood that multiple total reflection mirrors 30 can also be provided in the optical display module 110. The light of the display 20 is reflected multiple times in the multiple total reflection mirrors 30 to form a virtual image V that is farther from the flat lens 10, thereby further reducing the thickness of the optical display module 110'.

[0106] As Figure 14 shown, the preparation method of the flat lens according to an embodiment of the present application includes the following steps S10 to S20. According to different requirements, the order of some steps or sub-steps of the preparation method of the flat lens can be changed, and some steps or sub-steps can be omitted or combined.

[0107] Step S10: Form an anti-counterfeiting layer on the surface of the light-transmitting first substrate.

[0108] Specifically, the anti-counterfeiting layer 12 can be formed by one of the processes of chemical vapor deposition, atomic layer deposition, magnetron sputtering, and evaporation. Hereinafter, the process of preparing the anti-counterfeiting layer 12 by magnetron sputtering will be used as an example for illustration.

[0109] In some embodiments, the coating equipment uses a two-chamber magnetron single machine, but is not limited thereto.

[0110] Specifically, the first substrate 11 (made of glass) is installed on the rotating rack of the coating equipment, and the surface of the first substrate 11 is shielded by a mask plate 200, and then it enters the rough pumping chamber. The fine pumping heating temperature is 200 °C, and the first substrate 11 is degassed for 30 minutes, and then ion cleaning is carried out. The purpose of the ion cleaning treatment is to process the surface impurities and particle points of the first substrate 11, and a low-power mode is adopted to prevent the surface of the first substrate 11 from being damaged, and the power does not exceed 1 KW. Among them, during the ion cleaning treatment, the target cleaning in the coating chamber can be synchronously started to clean the oxide on the target surface before coating.

[0111] After the ion cleaning and target cleaning are completed, the first substrate 11 enters the coating chamber to deposit the first layer of film. The target material is selected as Si target, and the power supply uses an intermediate frequency power supply. The intermediate frequency power supply uses a high-power power supply with a power of 50 kw. Then, 50 sccm of reaction gas oxygen is introduced into the coating chamber to ensure that silicon is completely oxidized to form silicon dioxide. The first layer of film is deposited using 2 pairs of targets, and the target material, power, power supply, and process gas are all the same. The cumulative thickness of the film layer is 229 nm.

[0112] Then, the second layer of film is deposited. The target material is selected as TiO target, the power supply uses an intermediate frequency power supply with a power of 25 kw, the single-layer film formation thickness is 229 nm, and 35 sccm of reaction gas oxygen is introduced to ensure that titanium oxide is completely oxidized to form titanium dioxide. The second layer of film is deposited using 2 pairs of targets, and the target material, power, power supply, and process gas are all the same. The cumulative thickness of the film layer is 19 nm.

[0113] Then, other film layers are continuously formed. Specifically, for the third, fifth, seventh, ninth, eleventh, thirteenth, and fifteenth layers of film, the process parameters are the same as those for depositing the first layer of film, except for the film layer thickness. The thicknesses of the third, fifth, seventh, ninth, eleventh, thirteenth, and fifteenth layers of film are 45 nm, 35 nm, 32 nm, 32 nm, 146 nm, 42 nm, and 84 nm respectively. The film layer thickness is adjusted by controlling the change of the coating time. For the fourth, sixth, eighth, tenth, twelfth, and fourteenth layers of film, the process parameters are the same as those for depositing the second layer of film, except for the film layer thickness. The thicknesses of the fourth, sixth, eighth, tenth, twelfth, and fourteenth layers of film are: 44 nm, 47 nm, 51 nm, 26 nm, 15 nm, and 224 nm respectively. The film layer thickness is adjusted by controlling the change of the coating time. After the film is deposited, the rotating rack enters the rough pumping chamber, and the wafer is taken out to complete the coating of the anti-counterfeiting layer 12.

[0114] In other embodiments, the flow rate of the reaction gas oxygen for forming silicon dioxide and the power of the power supply are not limited to the above, and the flow rate of the reaction gas oxygen for forming titanium dioxide and the power of the power supply are not limited to the above.

[0115] Step S20: Bond the optical waveguide layer to the side of the first substrate where the anti-counterfeiting layer is formed.

[0116] In some embodiments, the flat lens 10 further includes a second substrate 14. The method for manufacturing the flat lens 10 further includes attaching the light-transmissive second substrate 14 to the side of the optical waveguide layer 13 away from the first substrate 11.

[0117] The above embodiments are only used to illustrate the technical solutions of the present application and not to limit them. Although the present application has been described in detail with reference to the above preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present application can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present application.

Claims

1. A flat lens, characterized in that, Comprising: A light-transmitting first substrate; An anti-counterfeiting layer located on the surface of the first substrate. The anti-counterfeiting layer includes alternately stacked high-refractive-index layers and low-refractive-index layers. The refractive index of the high-refractive-index layer is greater than that of the low-refractive-index layer. The anti-counterfeiting layer allows visible light to pass through but does not allow ultraviolet light to pass through; and An optical waveguide layer attached to the side of the anti-counterfeiting layer away from the first substrate. The optical waveguide includes a plurality of first reflection units and a plurality of second reflection units. Each first reflection unit extends in a first direction, and each second reflection unit extends in a second direction. In a third direction, the first reflection units and the second reflection units are orthogonally arranged, and the first direction, the second direction, and the third direction are perpendicular to each other in pairs.

2. The flat lens according to claim 1, characterized in that, The refractive index of the high-refractive-index layer is not less than 1.9, and the refractive index of the low-refractive-index layer is not greater than 1.

55.

3. The flat lens according to claim 1, characterized in that, The thickness of the high-refractive-index layer ranges from 15 nm to 224 nm, and the thickness of the low-refractive-index layer ranges from 32 nm to 229 nm.

4. The flat lens according to claim 1, wherein The total number of layers of the high-refractive-index layer and the low-refractive-index layer is not less than 9 layers.

5. The flat lens according to claim 1, characterized in that, The material of the high-refractive-index layer is selected from at least one of titanium dioxide and zinc oxide, and the material of the low-refractive-index layer is selected from at least one of silicon dioxide and silicon oxynitride.

6. The flat lens according to any one of claims 1 to 5, characterized in that, The flat lens further includes a light-transmitting second substrate attached to the side of the optical waveguide layer away from the first substrate.

7. A method for preparing a flat lens, characterized in that, Comprising: Forming an anti-counterfeiting layer on the surface of a light-transmitting first substrate. The anti-counterfeiting layer includes alternately stacked high-refractive-index layers and low-refractive-index layers. The refractive index of the high-refractive-index layer is greater than that of the low-refractive-index layer. The anti-counterfeiting layer allows visible light to pass through but does not allow ultraviolet light to pass through; And Attaching an optical waveguide layer to the side of the first substrate where the anti-counterfeiting layer is formed. The optical waveguide includes a plurality of first reflection units and a plurality of second reflection units. Each first reflection unit extends in a first direction, and each second reflection unit extends in a second direction. In a third direction, the first reflection units and the second reflection units are orthogonally arranged, and the first direction, the second direction, and the third direction are perpendicular to each other in pairs.

8. The manufacturing method of the flat lens according to claim 7, characterized in that, The anti-counterfeiting layer is formed by one of the processes of chemical vapor deposition, atomic layer deposition, magnetron sputtering, and evaporation.

9. The manufacturing method of the flat lens according to claim 7 or 8, characterized in that, The preparation method further includes attaching a light-transmitting second substrate to the side of the optical waveguide layer away from the first substrate.

10. An electronic device, characterized in that, Comprising: A display for emitting image light; And A flat lens according to any one of claims 1 to 6, located on one side of the display; Wherein, the flat lens is used to converge the image light to form a floating real image on the side of the flat lens away from the display.

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