Optical film with multiple periodic gratings
By combining the design of a multi-period grating structure and photoelectric sensor, the existing grating diffraction devices have solved the problem of high incidence angle requirements, and the expansion of the incident angle range and continuous angle work are achieved, which improves the sensitivity and usage experience of the interactive system.
Patent Information
- Application Number
- CN202510863273.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-25
- Publication Date
- 2025-08-12
AI Technical Summary
The existing grating diffraction devices have high requirements for incident angles and narrow working angles, which limit the viewing angle and interaction angle of the interactive system and affect the user's experience of use.
An optical film with multiple periodic gratings is designed. The grating includes multiple periodic structures, each period corresponds to an incident angle range. The grating structure is arranged according to the periodic size. The upper boundary of the incident angle of the adjacent grating structures meets a certain relationship. The diffracted light is received in conjunction with the photoelectric sensor to determine the incident position.
The angle range of incident light is expanded, the continuous operation of incident angle is achieved, and the sensitivity and usage experience of the interactive system are improved.
Smart Images
Figure CN120468985A_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to an optical film having multiple periodic gratings, and belongs to the technical field of optical devices. Background Art
[0002] Grating diffraction technology has applications in many fields, such as light interaction, light modulation, and optical illumination. When light is incident on the grating, it diffracts and couples into the waveguide layer. The grating waveguide can transmit the incident light to the side, creating a filtering effect.
[0003] However, most current grating diffraction devices have very high requirements for incident angles and a narrow operating angle. This is because the gratings they use have a single-period structure, which results in a high diffraction efficiency at only a specific angle for incident light of a certain wavelength. If the light is incident at other angles, the diffraction efficiency decreases rapidly until it becomes inoperable. This characteristic not only limits the viewing and interaction angles of interactive systems, affecting their sensitivity, but also significantly impacts the user experience. Summary of the Invention
[0004] In order to overcome the above problems, the present disclosure provides an optical film having multiple periodic gratings.
[0005] The technical solutions disclosed in this disclosure are as follows:
[0006] The present disclosure provides an optical film having multiple periodic gratings, comprising a grating disposed above a waveguide, wherein a photoelectric sensor is disposed on a side of the waveguide; the wavelength of the incident light is an operating wavelength;
[0007] The grating includes grating structures of multiple periods, each period of the grating structure corresponds to an incident angle range, and when incident light within a specific incident angle range is diffracted by the corresponding grating structure and enters the waveguide, total internal reflection is achieved in the waveguide;
[0008] Arrange the grating structures according to the period size, and any two adjacent grating structures satisfy:
[0009] The upper boundary of the incident angle corresponding to the grating structure with a larger period is not less than the lower boundary of the incident angle corresponding to the grating structure with a smaller period;
[0010] The photoelectric sensor is used to receive the diffracted light propagating in the waveguide.
[0011] Furthermore, the grating includes a plurality of grating units composed of grating structures, the structures of the grating units are completely the same, and the grating units are one-dimensional grating units or two-dimensional grating units.
[0012] Furthermore, the grating unit includes a grating structure arranged in a transverse and / or longitudinal direction, and the grating structure arranged in a transverse and / or longitudinal direction includes a grating structure with multiple periods, and the photoelectric sensors are arranged around the waveguide.
[0013] Furthermore, grating structures arranged along the same direction and having different periods are arranged side by side along the grating direction.
[0014] Furthermore, the grating structures arranged in the same direction and having different periods are arranged along the vertical direction of the grating.
[0015] In one embodiment of the present disclosure, the photoelectric sensor determines the horizontal coordinate of the incident position of the incident light based on the position of the diffracted light output after diffraction by the transversely arranged grating structure, determines the vertical coordinate of the incident position of the incident light based on the position of the diffracted light output after diffraction by the longitudinally arranged grating structure, and determines the incident position of the incident light based on the horizontal coordinate and the vertical coordinate.
[0016] Furthermore, the incident light enters the waveguide after being diffracted by the grating, satisfying the diffracted light coupling equation:
[0017]
[0018] Where n1 is the refractive index of the waveguide, n0 is the refractive index of the cover layer above the waveguide, T is the period of the grating structure, θ i is the incident angle of the incident light, θ j is the diffraction angle, m=±n, n is an integer, λ is the operating wavelength;
[0019] The ±1st order diffracted light is output as a waveguide, and the diffraction angle must be greater than or equal to the total reflection angle θ C , and is less than 90°, that is:
[0020]
[0021] Furthermore, the operating wavelength is 980 nm, the transversely arranged grating structure includes a grating structure with a period of 600 nm and a grating structure with a period of 700 nm, and the longitudinally arranged grating structure includes a grating structure with a period of 600 nm and a grating structure with a period of 700 nm.
[0022] Furthermore, the area of the grating unit is smaller than the area of the incident light spot.
[0023] Furthermore, the material of the waveguide is one or more of PET, glass, TAC, COP and PC; the material of the grating is one or more of silica gel, resin, UV glue and PC;
[0024] The grating structure is prepared by UV transfer, hot stamping or photolithography;
[0025] The shape of the grating unit is square, triangle, fan or circle.
[0026] The present disclosure has the following beneficial effects:
[0027] The optical film disclosed herein comprises a plurality of periodic units, each of which integrates a grating structure of a plurality of periods. Working wavelengths at different angles have gratings of corresponding periods to generate diffracted light that satisfies total internal reflection in the waveguide. Moreover, for two adjacent periods, the upper boundary of the incident angle range of the grating with a larger period is greater than or equal to the lower boundary of the incident angle range of the grating with a smaller period, thereby achieving the effect of increasing the incident angle range and satisfying the continuity of the incident working angle. BRIEF DESCRIPTION OF THE DRAWINGS
[0028] Figure 1 Schematic diagram of the working principle of the present invention.
[0029] Figure 2 Schematic diagram of a one-dimensional grating structure according to an embodiment of the present disclosure.
[0030] Figure 3 Schematic diagram of one-dimensional grating composite structure in different directions according to an embodiment of the present disclosure.
[0031] Figure 4 Schematic diagram of a two-dimensional grating structure according to an embodiment of the present disclosure.
[0032] Figure 5 Schematic diagram of a grating unit according to an embodiment of the present disclosure.
[0033] Figure 6 and 7 Schematic diagram of the incident angle range of grating structures with different periods according to the embodiment of the present disclosure.
[0034] Figure 8 and 9 Schematic diagram of the grating structure arrangement according to an embodiment of the present disclosure.
[0035] Figure 10 Schematic diagram of the parallel arrangement of one-dimensional gratings with different periods.
[0036] Figure 11 Schematic diagram of one-dimensional gratings with different periods arranged in sequence.
[0037] Figure 12 Schematic diagram of the direction of diffracted light generated by arranging one-dimensional gratings of different periods in parallel.
[0038] Figure 13 Schematic diagram of the direction of diffracted light generated by arranging one-dimensional gratings of different periods in sequence.
[0039] The reference numerals in the figures are as follows:
[0040] 1. Incident light; 2. Waveguide; 3. Grating; 4. Diffracted light; 5. Photoelectric sensor; 6. Grating unit. DETAILED DESCRIPTION
[0041] In order to make the purpose, technical solutions and advantages of the embodiments of the present disclosure more clear, the technical solutions of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.
[0042] Unless otherwise defined, the technical or scientific terms used in this disclosure should have the usual meanings understood by people with ordinary skills in the field to which this disclosure belongs. The "first", "second" and similar words used in this disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly. In order to keep the following description of the embodiments of the present disclosure clear and concise, the present disclosure omits detailed descriptions of some known functions and known components.
[0043] The present disclosure will be described in detail below with reference to the accompanying drawings and specific embodiments.
[0044] like Figure 1 As shown, in one embodiment of the present disclosure, an optical film having multiple periodic gratings is provided, including a grating 3 disposed above a waveguide 2, a photoelectric sensor 5 being disposed on the side of the waveguide 2; the wavelength of the incident light 1 is the operating wavelength;
[0045] The grating 3 includes grating structures of multiple periods, each period of the grating structure corresponds to an incident angle range. When the incident light 1 incident within a specific incident angle range is diffracted by the corresponding grating structure and enters the waveguide 2, it satisfies total internal reflection in the waveguide 2.
[0046] Arrange the grating structures according to the period size, and any two adjacent grating structures satisfy:
[0047] The upper boundary of the incident angle corresponding to the grating structure with a larger period is not less than the lower boundary of the incident angle corresponding to the grating structure with a smaller period;
[0048] The photoelectric sensor 5 is used to receive the diffracted light 4 propagating in the waveguide 2 .
[0049] like Figure 6 and 7 As shown, since the optical film includes a grating structure with multiple periods, the grating structures with different periods can diffract the incident light 1 with different incident angles and couple it into the waveguide 2, thereby expanding the incident angle range of the optical film to the incident light 1.
[0050] In one embodiment of the present disclosure, the grating 3 includes a plurality of grating units 6 composed of grating structures. The structures of the grating units 6 are completely identical. The grating units 6 are one-dimensional grating units or two-dimensional grating units.
[0051] Figure 2 is a one-dimensional grating unit 6, Figure 4 It is a two-dimensional grating unit 6.
[0052] like Figure 5 、 8 As shown in FIG9 , the optical film is composed of completely identical grating units 6 , so that the incident light 1 can be emitted uniformly on the optical film.
[0053] In one embodiment of the present disclosure, the grating unit 6 includes a grating structure arranged in the horizontal and / or vertical direction, and the grating structure arranged in the horizontal and / or vertical direction includes a grating structure with multiple periods, and the photoelectric sensors 5 are arranged around the waveguide 2.
[0054] Figure 2 The grating unit 6 only includes grating structures arranged horizontally or vertically.
[0055] Figure 3 The grating unit 6 includes both horizontally and vertically arranged grating structures.
[0056] When the grating unit 6 includes a grating structure arranged horizontally or vertically, the light can be emitted from a specific direction. When the grating unit 6 includes a grating structure arranged horizontally and vertically, the light can be emitted from two perpendicular directions.
[0057] like Figure 10 and 12 As shown, in one embodiment of the present disclosure, grating structures arranged along the same direction and with different periods are arranged side by side along the grating direction.
[0058] One-dimensional gratings of different periods arranged in parallel have the same period in the propagation direction of the diffracted light, and the diffraction angle of the diffracted light generated is the same. In addition, the wavelength of the diffracted light generated by gratings with the same period is the same, so there is no interference with each other, and the diffraction efficiency is high; while one-dimensional gratings of different periods arranged in sequence have different periods in the propagation direction of the diffracted light, and the diffraction angle of the diffracted light generated is also different. The wavelength of the diffracted light generated by gratings with different periods is also different, so they will interfere with each other, thereby reducing the propagation diffraction efficiency.
[0059] like Figure 11 and 13 As shown, in one embodiment of the present disclosure, grating structures arranged in the same direction and with different periods are arranged along the vertical direction of the grating.
[0060] In one embodiment of the present disclosure, the photoelectric sensor 5 determines the horizontal coordinate of the incident position of the incident light 1 based on the position of the diffracted light 4 output after diffraction by the transversely arranged grating structure, determines the vertical coordinate of the incident position of the incident light 1 based on the position of the diffracted light 4 output after diffraction by the longitudinally arranged grating structure, and determines the incident position of the incident light 1 based on the horizontal coordinate and the vertical coordinate.
[0061] In one embodiment of the present disclosure, the incident light 1 enters the waveguide 2 after being diffracted by the grating 3, satisfying the diffracted light coupling equation:
[0062]
[0063] Wherein, n1 is the refractive index of the waveguide 2, n0 is the refractive index of the cover layer above the waveguide 2, T is the period of the grating structure, θ i is the incident angle of the incident light, θ j is the diffraction angle, m=±n, n is an integer, λ is the operating wavelength;
[0064] The ±1st order diffraction light 4 is output as waveguide 2, and the diffraction angle must be greater than or equal to the total reflection angle θ C , and less than 90°.
[0065] Then the formula:
[0066]
[0067] Simplified to:
[0068]
[0069] The diffraction angle θ j Greater than or equal to the total reflection angle θ C Substituting into the above formula, we can get:
[0070] Also because Substitution
[0071] Also because Substitution
[0072] The diffraction angle θ j Less than 90°, and sin90=1, substitute into the formula We can get:
[0073]
[0074] Right now:
[0075]
[0076] In one embodiment of the present disclosure, the operating wavelength is 980 nm, the transversely arranged grating structure includes a grating structure with a period of 600 nm and a grating structure with a period of 700 nm, and the longitudinally arranged grating structure includes a grating structure with a period of 600 nm and a grating structure with a period of 700 nm.
[0077] In this embodiment, the incident angle corresponding to the 600nm grating is -39.05° to -2.86°, and the incident angle corresponding to the 700nm period grating is -23.58 to 10.37°, so that the incident angles of two adjacent periods overlap by 20.72°, so that the incident angle is expanded from 36.19° to 49.42°, and is continuous within this range.
[0078] The incident angle is the angle between the incident light and the normal line. An incident angle of 0° indicates that the incident light is perpendicular to the grating structure. For example, a clockwise rotation along the normal line is positive, and a counterclockwise rotation along the normal line is negative.
[0079] In one embodiment of the present disclosure, the area of the grating unit 6 is smaller than the spot area of the incident light 1 .
[0080] In one embodiment of the present disclosure, the material of the waveguide 2 is one or more of PET, glass, TAC, COP and PC; the material of the grating 3 is one or more of silica gel, resin, UV glue and PC;
[0081] The grating structure is prepared by UV transfer, hot stamping or photolithography;
[0082] The shape of the grating unit is square, triangle, fan or circle.
[0083] The flowcharts and block diagrams in the accompanying drawings illustrate the possible implementation architecture, functions and operations of the systems, methods and computer program products according to various embodiments of the present disclosure. In this regard, each box in the flowchart or block diagram can represent a module, program segment, or a part of code, and the module, program segment, or a part of code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in a different order than that marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or flowchart, and the combination of the boxes in the block diagram and / or flowchart, can be implemented with a dedicated hardware-based system that performs the specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.
[0084] The units involved in the embodiments described in this disclosure may be implemented in software or hardware, wherein the name of a unit does not necessarily limit the unit itself.
[0085] The functions described above herein may be performed, at least in part, by one or more hardware logic components. For example, and without limitation, exemplary types of hardware logic components that may be used include: field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), application specific standard products (ASSPs), systems on chip (SOCs), complex programmable logic devices (CPLDs), and the like.
[0086] The above description is merely a preferred embodiment of the present disclosure and an illustration of the technical principles employed. Those skilled in the art should understand that the scope of disclosure involved in the present disclosure is not limited to the technical solutions formed by the specific combination of the above-mentioned technical features, but also includes other technical solutions formed by any combination of the above-mentioned technical features or their equivalents without departing from the above-mentioned disclosed concepts. For example, a technical solution formed by replacing the above-mentioned features with (but not limited to) technical features with similar functions disclosed in this disclosure.
[0087] In addition, although each operation is described in a specific order, this should not be understood as requiring these operations to be performed in the specific order shown or in a sequential order. Under certain circumstances, multitasking and parallel processing may be advantageous. Similarly, although some specific implementation details have been included in the above discussion, these should not be interpreted as limiting the scope of the present disclosure. Some features described in the context of a separate embodiment can also be implemented in a single embodiment in combination. On the contrary, the various features described in the context of a single embodiment can also be implemented in multiple embodiments individually or in any suitable sub-combination mode.
[0088] Although the subject matter has been described in language specific to structural features and / or methodological logical acts, it should be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are merely example forms of implementing the claims.
[0089] Regarding this disclosure, the following points need to be explained:
[0090] (1) The drawings of the embodiments of the present disclosure only relate to the structures related to the embodiments of the present disclosure. Other structures may refer to conventional designs.
[0091] (2) In the absence of conflict, the embodiments of the present disclosure and the features therein may be combined with each other to form new embodiments.
[0092] The above descriptions are merely embodiments of the present disclosure and are not intended to limit the patent scope of the present disclosure. Any equivalent structures made using the contents of the present disclosure and the drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present disclosure.
Claims
1. An optical film having multiple periodic gratings, characterized in that: The invention comprises a grating (3) arranged above a waveguide (2), and a photoelectric sensor (5) is arranged on the side of the waveguide (2); the wavelength of the incident light (1) is the working wavelength; The grating (3) includes grating structures of multiple periods, each period of the grating structure corresponds to an incident angle range, and when the incident light (1) incident within the specific incident angle range is diffracted by the corresponding grating structure and enters the waveguide (2), total reflection is satisfied in the waveguide (2); Arrange the grating structures according to the period size, and any two adjacent grating structures satisfy: The upper boundary of the incident angle corresponding to the grating structure with a larger period is not less than the lower boundary of the incident angle corresponding to the grating structure with a smaller period; The photoelectric sensor (5) is used to receive the diffracted light (4) propagating in the waveguide (2).
2. The optical film having multiple periodic gratings according to claim 1, wherein: The grating (3) comprises a plurality of grating units (6) composed of grating structures, the structures of the grating units (6) are completely identical, and the grating units (6) are one-dimensional grating units or two-dimensional grating units.
3. The optical film having multiple periodic gratings according to claim 2, wherein: The grating unit (6) includes a grating structure arranged in a transverse and / or longitudinal direction, and the grating structure arranged in a transverse and / or longitudinal direction includes a grating structure with multiple periods. The photoelectric sensors (5) are arranged around the waveguide (2).
4. The optical film having multiple periodic gratings according to claim 1, wherein: Grating structures arranged in the same direction and with different periods are arranged side by side along the grating direction.
5. The optical film having multiple periodic gratings according to claim 1, wherein: The grating structures arranged in the same direction and with different periods are arranged along the vertical direction of the grating.
6. The optical film having multiple periodic gratings according to any one of claims 1 to 5, characterized in that: The photoelectric sensor (5) determines the horizontal coordinate of the incident position of the incident light (1) based on the position of the diffracted light (4) output after diffraction by the transversely arranged grating structure, determines the vertical coordinate of the incident position of the incident light (1) based on the position of the diffracted light (4) output after diffraction by the longitudinally arranged grating structure, and determines the incident position of the incident light (1) based on the horizontal coordinate and the vertical coordinate.
7. The optical film having multiple periodic gratings according to claim 6, wherein: The incident light (1) enters the waveguide (2) after being diffracted by the grating (3), satisfying the diffracted light coupling equation: Wherein, n1 is the refractive index of the waveguide (2), n0 is the refractive index of the cover layer above the waveguide (2), T is the period of the grating structure, θ i is the incident angle of the incident light, θ j is the diffraction angle, m=±n, n is an integer, λ is the operating wavelength; The ±1st order diffracted light (4) is output as the waveguide (2), and the diffraction angle must be greater than or equal to the total reflection angle θ C , and is less than 90°, that is:
8. The optical film having multiple periodic gratings according to claim 6, wherein: The operating wavelength is 980nm, the transversely arranged grating structure includes a grating structure with a period of 600nm and a grating structure with a period of 700nm, and the longitudinally arranged grating structure includes a grating structure with a period of 600nm and a grating structure with a period of 700nm.
9. The optical film having multiple periodic gratings according to claim 6, wherein: The area of the grating unit (6) is smaller than the spot area of the incident light (1).
10. The optical film having multiple periodic gratings according to claim 6, wherein: The material of the waveguide (2) is one or more of PET, glass, TAC, COP and PC; the material of the grating (3) is one or more of silica gel, resin, UV glue and PC; The grating structure is prepared by UV transfer, hot stamping or photolithography; The shape of the grating unit is square, triangle, fan or circle.