Optical fiber type interference exposure system and interference exposure adjusting method

Abstract

The invention discloses an optical fiber type interference exposure system and an interference exposure adjustment method, and relates to the technical field of holographic gratings, and the system comprises a light guide assembly which comprises a first optical fiber and a second optical fiber; the grating substrate is provided with a plurality of exposure positions, and the first coherent light and the second coherent light led out by the light guide assembly form an interference exposure field on the grating substrate; the compensation device is provided with a plurality of compensation areas, each compensation area is provided with a compensation deflection angle corresponding to one exposure position, and the compensation device is arranged on a propagation path of at least one beam of light in the first coherent light and the second coherent light. Therefore, the interference solid angles of the incident first coherent light and the second coherent light at the corresponding exposure positions are adjusted through the compensation area on the compensation device, so that the grating obtained by interference exposure has the same grating angle at different exposure positions of the grating substrate, and the consistency and uniformity of the grating angle are ensured; and a good imaging effect of the grating is achieved.

Description

Technical Field

[0001] The present application relates to the technical field of holographic gratings, and more specifically, to a fiber-optic interference exposure system and an interference exposure adjustment method. Background Art

[0002] In the field of Augmented Reality (AR) optical waveguide display, the waveguide solution with array grating as the mainstream technology is becoming the mainstream technology. Commonly used array gratings mainly include one-dimensional gratings including tilted gratings, trapezoidal gratings, blazed gratings and rectangular grating structures. At present, the interference exposure method is generally used for grating preparation. The laser double-beam interference exposure system uses the divergent light fields emitted by two or more optical fibers to perform spatial interference to form an interference exposure field, and uses the interference exposure field to expose the photoresist on the grating substrate and perform subsequent operations to finally form a grating.

[0003] However, since the two beams of light emitted from the optical fiber will form an uneven spatial solid angle in space, the grating formed by its interference exposure will have an uneven grating deflection angle distribution at different positions, causing the imaging of the grating after pupil expansion to have ghosting, affecting the display effect of the grating in practical applications. Summary of the invention

[0004] The present application proposes a fiber-optic interference exposure system and an interference exposure adjustment method to improve the above-mentioned defects.

[0005] In a first aspect, an embodiment of the present application provides a fiber-type interference exposure system, comprising: a light guide component, the light guide component comprising a first optical fiber and a second optical fiber, the first optical fiber being used to lead out a first coherent light, and the second optical fiber being used to lead out a second coherent light; a grating substrate, the grating substrate having a plurality of exposure positions, the first coherent light and the second coherent light being propagated to the grating substrate via different paths to form an interference exposure field; a compensation device, the compensation device having a plurality of compensation areas, each of the compensation areas corresponding to one of the exposure positions, and each of the compensation areas having a corresponding compensation deflection angle, the compensation device being arranged on a propagation path of at least one beam of the first coherent light and the second coherent light, and being used to adjust the interference solid angle of the first coherent light and the second coherent light at the corresponding exposure position through the compensation area, so that the grating angles of the gratings formed under the interference exposure field at the plurality of exposure positions are all the same.

[0006] Optionally, the compensation device is a holographic optical element, and the refractive index of each compensation region is set based on its corresponding compensation deflection angle to adjust the interference solid angle of the first coherent light and the second coherent light passing through the holographic optical element.

[0007] Optionally, the compensation device is a curved lens, and the surface curvature of each compensation area is set based on its corresponding compensation deflection angle to adjust the interference solid angle of the first coherent light and the second coherent light passing through the curved lens.

[0008] Optionally, the placement center of the compensation device is located on the bisector of an angle formed by the light outlet of the first optical fiber, the light outlet of the second optical fiber and the center point of the grating substrate.

[0009] Optionally, the compensation device is a reflector, and the reflectivity of each of the compensation areas is set based on its corresponding compensation deflection angle. The reflector is arranged on the propagation path of the specific coherent light, and is used to change the incident angle of the specific coherent light incident on the exposure plane to adjust the interference solid angle of the first coherent light and the second coherent light, wherein the specific coherent light is the first coherent light or the second coherent light.

[0010] Optionally, the reflection center of the reflector completely coincides with the position of the coherent light spot when the specific coherent light enters the reflector.

[0011] Optionally, the system further comprises a mask, wherein the mask is arranged on an optical path of the first coherent light and the second coherent light emitted from the compensation device to the grating substrate.

[0012] In a second aspect, an embodiment of the present application further provides an interference exposure adjustment method, which is applied to the above-mentioned fiber-optic interference exposure system, and the method includes: adjusting the interference solid angle of the first coherent light and the second coherent light at the corresponding exposure position through the compensation angle of the compensation area, so that the grating angles of the grating formed under the interference exposure field at the exposure position are all the same.

[0013] Optionally, the method further includes: acquiring first relative position data between the light outlet of the first optical fiber and the center point of the grating substrate, and second relative position data between the light outlet of the second optical fiber and the center point of the grating substrate; and calculating the compensation angle according to the first relative position data and the second relative position data.

[0014] Optionally, the maximum value θ of the compensation deflection angle is max Satisfy: θ max ≥θ 1 / 2-θ 2 / 2; where θ 1 is the angle formed by the equivalent light vector of the first coherent light and the equivalent light vector of the second coherent light at the center point of the grating substrate, θ 2is the angle formed by the equivalent light vector of the first coherent light and the equivalent light vector of the second coherent light at the point on the grating substrate farthest from the central point.

[0015] Therefore, the present application provides a fiber-type interference exposure system, comprising: a light guide component, the light guide component comprising a first optical fiber and a second optical fiber, the first optical fiber being used to lead out a first coherent light, and the second optical fiber being used to lead out a second coherent light; a grating substrate, the grating substrate having a plurality of exposure positions, the first coherent light and the second coherent light being propagated to the grating substrate via different paths to form an interference exposure field; a compensation device, the compensation device having a plurality of compensation areas, each of the compensation areas corresponding to one of the exposure positions, and each of the compensation areas having a corresponding compensation deflection angle, the compensation device being arranged on the propagation path of at least one beam of light among the first coherent light and the second coherent light, so that the interference solid angle of the incident first coherent light and the second coherent light at the corresponding exposure position can be adjusted through the compensation area on the compensation device, so that the grating obtained by interference exposure under the interference exposure field formed by the first coherent light and the second coherent light has the same grating angle at different exposure positions of the grating substrate, thereby ensuring the consistency and uniformity of the grating angle, and ensuring the imaging effect of the grating obtained by the interference exposure system.

[0016] Other features and advantages of the embodiments of the present application will be described in the subsequent description, and partly become apparent from the description, or can be understood by practicing the embodiments of the present application. The purposes and other advantages of the embodiments of the present application can be realized and obtained by the structures specifically pointed out in the written description, claims, and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0018] Figure 1 A schematic diagram of a grating formed by two spherical wave interference exposure in an embodiment of the present application is shown.

[0019] Figure 2 A grating angle distribution diagram of two spherical wave interference exposure in an embodiment of the present application is shown.

[0020] Figure 3 A schematic structural diagram of a fiber-optic interference exposure system according to an embodiment of the present application is shown.

[0021] Figure 4A schematic structural diagram of another fiber-optic interference exposure system according to an embodiment of the present application is shown.

[0022] Figure 5 A schematic structural diagram of another fiber-optic interference exposure system according to an embodiment of the present application is shown.

[0023] Figure 6 A method flow chart of an interference exposure adjustment method provided in an embodiment of the present application is shown.

[0024] Figure 7 A flow chart of a method for obtaining a compensation angle of a compensation device in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0025] In order to make those skilled in the art better understand the present application scheme, the technical scheme in the present application embodiment will be clearly and completely described below in conjunction with the drawings in the present application embodiment. Obviously, the described embodiment is only a part of the present application embodiment, rather than all the embodiments. The components of the present application embodiment usually described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the present application for protection, but merely represents the selected embodiment of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present application.

[0026] It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. At the same time, in the description of this application, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0027] In the prior art, an interference exposure system is generally composed of a laser light source, two optical fibers and an exposure plane, wherein each optical fiber has a corresponding light outlet. The interference exposure system divides the laser light emitted by the laser light source into two coherent light beams, and uses two optical fibers to guide the two coherent light beams out, so that the two coherent light beams are emitted from their respective optical fiber light outlets. The divergent light fields of the two coherent light beams are spatially interfered, and an illuminated area and a non-illuminated area are formed through constructive and destructive interference, thereby forming an interference exposure field on the exposure plane to expose the photoresist on the exposure plane and finally form a grating. Generally speaking, before designing an interference exposure system, it is necessary to first obtain the theoretical relative position data between the two optical fiber light outlets and the grating substrate based on the design and production requirements of the grating, and determine and set the specific positions of the optical fiber light outlets and the grating substrate according to the theoretical relative position data. However, due to the inevitable positional deviation in the actual setting process, there is a certain deviation between the actual relative position data between the two optical fiber light outlets and the grating substrate in the actual interference exposure system and the theoretical data, so that the spatial solid angle formed in space by the spherical waves corresponding to the two coherent light beams emitted from the two optical fiber light outlets is not the theoretically expected solid angle distribution, that is, in actual circumstances, the spatial solid angle formed in space by the spherical waves corresponding to the two coherent light beams emitted from the two optical fiber light outlets is uneven, resulting in uneven interference exposure fields formed by the two coherent light beams on the exposure plane, which will cause different grating deflection angles formed by the interference exposure field at different positions on the exposure plane, ultimately affecting the imaging effect of the grating formed under the interference exposure field.

[0028] See also Figure 1 , Figure 1 A schematic diagram of a grating formed by two spherical wave interference exposure in an embodiment of the present application is shown, wherein the exposure position O is the center point on the grating substrate, and the exposure position A is the point on the grating substrate farthest from the center point O. It can be seen that the angle of the grating at the exposure position farthest from the center point O is significantly different from the angle of the grating at the exposure position located at the center point of the grating substrate. For further information, please refer to Figure 2 , Figure 2 A deflection angle distribution diagram of a two-spherical wave interference exposure in an embodiment of the present application is shown, where the x-axis in the diagram refers to the horizontal axis of a rectangular coordinate system established with the grating substrate as a plane and the center point O of the grating substrate as the origin, and the y-axis in the diagram refers to the vertical axis in the above rectangular coordinate system. It can be understood that the x-axis can represent the horizontal coordinate (unit mm) of the point corresponding to each exposure position on the grating substrate, and the y-axis can represent the vertical coordinate (unit mm) of the point corresponding to each exposure position on the grating substrate. Any point on the plane formed by the x-axis and the y-axis can correspond to any exposure position on the grating substrate, and the z-axis is used to represent the grating angle (unit °) of the exposure position of each corresponding point coordinate on the grating substrate. Therefore, it can be obtained by Figure 2It can be seen that, in general, when the interference exposure system is used to expose the grating substrate, the grating angle when the exposure position coordinates on the grating substrate are (0,0), that is, the exposure position is the center point of the grating substrate, is significantly different from the grating angle when the exposure position on the grating substrate is not the center point of the grating substrate, and the grating angles at different exposure positions on the grating substrate are different.

[0029] Therefore, please refer to Figure 3 , Figure 3 The schematic diagram of the structure of a fiber-type interference exposure system of an embodiment of the present application is shown, comprising: a light guide component, a grating substrate 120 and a compensation device 130, wherein the light guide component comprises a first optical fiber 101 and a second optical fiber 102, the first optical fiber 101 is used to lead out a first coherent light, and the second optical fiber 102 is used to lead out a second coherent light, and the first coherent light is emitted from the light outlet of the first optical fiber 101, and the second coherent light is emitted from the light outlet of the second optical fiber 102, and propagates to the grating substrate along different paths, and interferes to form an interference exposure field. The compensation device 130 has a plurality of compensation areas, and each compensation area corresponds to an exposure position, and each compensation area has a corresponding compensation deflection angle. The compensation device 130 is arranged on the propagation path of at least one beam of the first coherent light and the second coherent light, and is used to adjust the interference solid angle of the first coherent light and the second coherent light at the corresponding exposure position through the compensation deflection angle of the compensation area, so that the interference exposure field formed by the first coherent light and the second coherent light adjusted by the compensation device 130 and the grating obtained by interference exposure on the grating substrate have the same grating angle at each exposure position.

[0030] As an embodiment, the system may further include a laser light source and a spectrometer (not shown in the figure), the spectrometer splits the light emitted by the laser light source into two coherent light beams, one beam is drawn out by the first optical fiber 101 as the first coherent light, and the other beam is drawn out by the second optical fiber 102 as the second coherent light, wherein the spectrometer may be a fiber optic beam splitter. It can be understood that obtaining the first coherent light and the second coherent light is not limited to the method shown in this embodiment and is not limited here.

[0031] Furthermore, the light outlet of the first optical fiber and the second optical fiber are point light sources, and the light emitted outward can be regarded as a spherical wave, whose equiphase surface is a concentric spherical surface that gradually expands with increasing distance from the light outlet. In other words, the first coherent light and the second coherent light have multiple equivalent light vectors with different directions in space. Figure 3The equivalent light vectors of the first coherent light and the second coherent light pointing in two directions are shown, wherein the light vectors L1 and L2 propagate along the path to the exposure position point 0 of the grating substrate 120 and interfere with each other, and the light vectors L3 and L4 propagate along the path to the exposure position point A of the grating substrate 120 and interfere with each other. According to the above analysis, since the spherical waves corresponding to the first coherent light and the second coherent light will form a non-uniform spatial solid angle in space, if the light vector L1 and the light vector L2 interfere directly at the exposure position 0, the grating angle formed by them is also inconsistent with the grating angle formed by the light vector L3 and the light vector L4 directly interfering at the exposure position A. However, since the compensation device 130 has a plurality of compensation areas, and each compensation area has a compensation deflection angle corresponding to an exposure position, that is, as long as the corresponding compensation deflection angle is set on the corresponding compensation area of ​​the compensation device 130 based on the grating angle deviation between the gratings formed by the first coherent light and the second coherent light at different exposure positions, the first coherent light and the second coherent light can be made to compensate for the angle deviation generated in the propagation process by the compensation deflection angle after entering the compensation device 130, so as to achieve that the grating angles of the gratings formed by the interference exposure of the grating substrate 120 at each exposure position are the same.

[0032] As an implementation method, Figure 3 As shown, the compensation device 130 may be a holographic optical element. The holographic optical element is an optical element made based on the holographic principle, and is usually made on a photosensitive film material. Furthermore, the multiple compensation areas of the holographic optical element have different refractive indices, and the refractive index of each compensation area is set based on the compensation deflection angle corresponding to the compensation area. Since the compensation deflection angle of each compensation area corresponds to an exposure position, Figure 3Taking an example for explanation, it can be understood that the exposure position point A on the grating substrate 120 corresponds to a compensation area where the first coherent light L3 is incident and a compensation area where the second coherent light L4 is incident on the compensation device 130. Therefore, as long as the grating angle formed by the unadjusted first coherent light L3 and the second coherent light L4 at the exposure position point A is determined, the coherent optical parameters of the two spherical waves of the first coherent light and the second coherent light can be derived, and the interference solid angle deviation of the two spherical waves in the interference process can be further obtained. Based on the obtained solid angle deviation, different compensation deflection angles can be achieved by setting different refractive indices on the compensation area of ​​the compensation device 130 accordingly, so that after the first coherent light L3 and the second coherent light L4 are incident on the corresponding compensation area, the interference solid angle deviation between the two spherical waves can be compensated by compensating the compensation deflection angle. Exemplarily, the compensation deflection angle may be obtained by measuring the actual relative position data between the light outlet of the first optical fiber and the light outlet of the second optical fiber and the grating substrate in the actual interference exposure system, and then calculating the grating angles of different exposure positions on the grating substrate based on the actual relative position data, and finally using the spatial stereo wave function simulation to solve the coherence distribution of the first coherent light spherical wave and the second coherent light spherical wave to obtain the offset value of the spatial distribution of the stereo angle during the interference exposure of the two spherical waves, and then the value of the compensation deflection angle can be obtained based on the offset value of the spatial distribution of the stereo angle.

[0033] Furthermore, when the compensation device is a holographic optical element, its preparation process may be: after the coherence distribution of the first coherent light spherical wave and the second coherent light spherical wave is solved based on the above steps, the spherical wave optical parameters such as amplitude, phase and light intensity of the two spherical waves corresponding to the grating angles at different exposure positions on the grating substrate are also obtained, and the film material for preparing the holographic optical element contains a photosensitive factor, and the photosensitive factor can record the phase through a photopolymerization reaction, that is, it can record the value of the grating angle corresponding to the spherical wave optical parameter, that is, the material refractive index for compensating the deflection angle of the grating angle can be further obtained. Taking the case where the equivalent light vector of the first coherent light is incident on a certain exposure position on the grating substrate as an example, after calculating the grating angle corresponding to the exposure position on the grating substrate, that is, the amplitude, phase and light intensity of the two spherical waves and other spherical wave optical parameters, the incident angle of the equivalent light vector of the first coherent light at the exposure position can be calculated, and based on the deviation between the actual grating angle and the theoretical grating angle, the compensation deflection angle that needs to be compensated at this point can be obtained, that is, the exit angle of the first coherent light after exiting the corresponding compensation area of ​​the compensation device can be obtained. Therefore, based on the law of refraction, it can be known that the refractive index of the compensation area should be equal to the ratio of the exit angle to the incident angle, and the calculation method of the refractive index of other compensation areas on the compensation device is the same as above. Therefore, by inputting the obtained spherical wave optical parameters into the exposure optical path of the holographic optical element to expose the thin film material of the holographic optical element, the refractive index of the compensation area can be obtained. The holographic optical element is set based on its corresponding compensation deflection angle, and the spherical wave interference solid angle of the first coherent light and the second coherent light can be adjusted by the holographic optical element.

[0034] Further, the placement center of the holographic optical element is located on the bisector of the angle formed by the light outlet of the first optical fiber, the light outlet of the second optical fiber and the center point O of the grating substrate, wherein the placement center of the holographic optical element may refer to the geometric center of the holographic optical element. It can be understood that after determining the placement position of the compensation device, it is easier to determine the position of the compensation area corresponding to different compensation deflection angles on the compensation device by calculating the offset value of the spatial distribution of the solid angle during the interference exposure of the two spherical waves, thereby improving the compensation accuracy of the compensation device.

[0035] As an implementation method, see Figure 4 , Figure 4A schematic diagram of the structure of another fiber-optic interference exposure system of an embodiment of the present application is shown, wherein the compensation device 130 may be a curved lens, and further, different surface curvatures are provided on multiple compensation areas of the curved lens, and the surface curvature of each compensation area is set based on the compensation deflection angle corresponding to the compensation area. Similarly, since the compensation deflection angle of each compensation area corresponds to an exposure position, as long as the grating angle formed by the unadjusted first coherent light L3 and the second coherent light L4 at the exposure position is determined, the coherent optical parameters of the two spherical waves of the first coherent light and the second coherent light can be derived, and the interference solid angle deviation of the two spherical waves in the interference process can be further obtained. Based on the obtained solid angle deviation, different compensation deflections are achieved by correspondingly setting different surface curvatures on the compensation area of ​​the compensation device 130, so that after the first coherent light L3 and the second coherent light L4 are incident on the corresponding compensation area, the interference solid angle deviation between the two spherical waves can be compensated by compensating the compensation deflection angle. Among them, the method for obtaining the compensation deflection angle can refer to the above-mentioned implementation method, that is, based on the actual relative position data between the light outlet of the first optical fiber and the light outlet of the second optical fiber and the grating substrate in the actual interference exposure system, the grating angles at different exposure positions on the grating substrate are calculated, and the offset value of the spatial distribution of the solid angle during the interference exposure of the two spherical waves is obtained, and finally the value of the compensation deflection angle is obtained.

[0036] Further, the placement center of the curved lens is located on the bisector of the angle formed by the light outlet of the first optical fiber and the light outlet of the second optical fiber and the center point O of the grating substrate, wherein the placement center may refer to the geometric center of the curved lens. It is understandable that after determining the placement position of the compensation device, it is easier to determine the position of the compensation area corresponding to different compensation deflection angles on the compensation device by calculating the offset value of the spatial distribution of the solid angle during the interference exposure of the two spherical waves, thereby improving the compensation accuracy of the compensation device.

[0037] As an implementation method, see Figure 5 , Figure 5A schematic diagram of the structure of another fiber-optic interference exposure system according to an embodiment of the present application is shown, wherein the compensation device 130 may be a reflector, exemplarily, a free-form surface reflector, and has different reflectivities on multiple compensation areas of the reflector, and the reflectivity of each compensation area is set based on its corresponding compensation deflection angle. Similarly, the compensation deflection angle corresponding to each compensation area is related to the grating angle at the exposure position corresponding to the compensation area. Therefore, when the grating angle formed by the unadjusted first coherent light L3 and the second coherent light L4 at each exposure position is determined, the interference solid angle deviation of the two spherical waves of the first coherent light and the second coherent light in the interference process can be derived, and based on the interference solid angle deviation, different compensation deflections are realized by setting different reflectivities on the compensation area of ​​the compensation device 130 accordingly, so that after the first coherent light L3 or the second coherent light L4 is incident on the corresponding compensation area, the interference solid angle deviation between the two spherical waves can be compensated by compensating the compensation deflection angle. The method for obtaining the compensation deflection angle can refer to the above-mentioned embodiment, which will not be repeated here.

[0038] The reflector is arranged on the propagation path of the specific coherent light, so as to adjust the interference solid angle of the first coherent light and the second coherent light by changing the incident angle of the specific coherent light incident on the grating substrate after being reflected by the reflector through the reflectivity of different compensation areas. Figure 5 In the example, the specific coherent light is taken as the first coherent light, but it should be understood that the specific coherent light can be the first coherent light or the second coherent light, and no limitation is made here. Further, the compensation deflection angle of the compensation area on the reflector can achieve that the first angle formed by the equivalent light vector of the first coherent light and the normal of the grating substrate at a certain exposure position of the grating substrate after being reflected by the reflector and reaching the grating substrate is equal to the second angle formed by the equivalent light vector of the second coherent light directly reaching the grating substrate and forming with the normal of the grating substrate at the same exposure position, thereby ensuring that the grating formed by the interference exposure of the first coherent light and the second coherent light on the grating substrate has the same grating angle at each exposure position.

[0039] Furthermore, the reflector is set so that its reflection center completely coincides with the position of the light spot of the specific coherent light incident on the reflector through the corresponding optical fiber light outlet, wherein the reflection center refers to the physical center point of the reflector, generally the geometric center. Exemplarily, when the specific coherent light is the first coherent light, that is, the position where the light spot of the light emitted from the light outlet of the first optical fiber is incident on the reflector completely coincides with the reflection center of the reflector, it can be understood that after determining the placement position, it is easier to determine the position of the compensation area corresponding to different compensation deflection angles on the compensation device by calculating the offset value of the spatial distribution of the stereoscopic angle during the interference exposure of the two spherical waves, thereby improving the compensation accuracy of the compensation device.

[0040] As an implementation method, see Figure 3 The fiber-optic interference exposure system also includes a mask 140. Generally, the process of making a grating in the interference exposure system includes the following steps: first, a photosensitive resin is coated on the photoresist layer, and then the pattern of the grating is irradiated onto the photosensitive resin by interference exposure. After irradiation, the unexposed part of the photosensitive resin is removed through process steps such as development and etching to form the pattern of the grating. Therefore, the mask is used to generate the shape of the grating during the interference exposure process. In this embodiment, the mask 140 is arranged on the optical path from the first coherent light and the second coherent light to the grating substrate through the compensation device, and is used to selectively transmit or block a part of the first coherent light and the second coherent light to generate a light field distribution with a specific shape and size, which can further ensure the uniformity of the grating angle in the effective exposure area on the grating substrate. It can be understood that in Figure 4 or Figure 5 The illustrated embodiment of a fiber-optic interference exposure system may also include a mask.

[0041] Therefore, the present application provides a fiber-type interference exposure system, comprising: a light guide component, the light guide component comprising a first optical fiber and a second optical fiber, the first optical fiber being used to lead out a first coherent light, and the second optical fiber being used to lead out a second coherent light; a grating substrate, the grating substrate having a plurality of exposure positions, the first coherent light and the second coherent light being propagated to the grating substrate via different paths to form an interference exposure field; a compensation device, the compensation device having a plurality of compensation areas, each of the compensation areas corresponding to one of the exposure positions, and each of the compensation areas having a corresponding compensation deflection angle, the compensation device being arranged on the propagation path of at least one beam of light among the first coherent light and the second coherent light, so that the interference solid angle of the incident first coherent light and the second coherent light at the corresponding exposure position can be adjusted through the compensation area on the compensation device, so that the grating obtained by interference exposure under the interference exposure field formed by the first coherent light and the second coherent light has the same grating angle at different exposure positions of the grating substrate, thereby ensuring the consistency and uniformity of the grating angle, and ensuring the imaging effect of the grating obtained by the interference exposure system.

[0042] See also Figure 6 , Figure 6 A method flow chart of an interference exposure adjustment method provided in an embodiment of the present application is shown, which is applied to the fiber-optic interference exposure system in the above embodiment. The method includes:

[0043] S110: adjusting the interference solid angle of the first coherent light and the second coherent light at the corresponding exposure position by means of the compensation deflection angle of the compensation area, so that the grating angles of the gratings formed in the interference exposure field at the exposure position are all the same.

[0044] The implementation of S110 may refer to the implementation of the aforementioned device, and will not be described in detail here.

[0045] As an implementation, see Figure 7 , Figure 7 A flow chart of a method for obtaining a compensation angle of a compensation device in an embodiment of the present application is shown, including:

[0046] S210: Acquire first relative position data between the light outlet of the first optical fiber and the center point of the grating substrate, and second relative position data between the light outlet of the second optical fiber and the center point of the grating substrate.

[0047] The center point of the grating substrate may refer to the geometric center of the grating substrate, and the relative position data between the optical fiber outlet and the center point of the grating substrate includes the position coordinates and angles of the optical fiber outlet and the center point of the grating substrate. As an implementation method, a high-precision microscope may be used for measurement, or an optical measuring instrument such as a laser interferometer may be used for precise measurement.

[0048] S220: Calculate the compensation angle according to the first relative position data and the second relative position data.

[0049] As an implementation mode, the method for calculating the compensation deflection angle according to the first relative position data and the second relative position data can be: using optical simulation software (such as FEMTO-photonics, etc.) to input data for simulation calculation, and finding the grating angle obtained by exposure, thereby, according to the obtained grating angle, using the spatial stereo wave function simulation to solve the coherent distribution of the spherical wave of the first coherent light and the spherical wave of the second coherent light, that is, the amplitude, wave number, angular frequency, radius and initial phase and other wave data of the two spherical waves can be obtained, that is, the distribution function of the two spherical waves is obtained, according to the principle of wave superposition, the coherent distribution of the two spherical waves is the superposition of the two spherical waves, therefore, by substituting the distribution function of the two spherical waves into the coherent distribution, the coherent distribution of the two spherical waves of the first coherent light and the second coherent light can be obtained, and then the offset value of the spatial distribution of the stereo angle of the two spherical waves during interference exposure is obtained from the coherent distribution of the two spherical waves, and the value of the compensation deflection angle is obtained based on the offset value of the spatial distribution of the stereo angle.

[0050] As an implementation method, the maximum value θ of the compensation deflection angle is max Satisfy: θ max >θ 1 / 2-θ 2 / 2; where θ 1 is the angle formed by the equivalent light vector of the first coherent light and the equivalent light vector of the second coherent light at the center point of the grating substrate, θ 2is the angle formed by the equivalent light vector of the first coherent light and the equivalent light vector of the second coherent light at the point on the grating substrate farthest from the center point. Figure 1 , Figure 1 The equivalent light vector n of the first coherent light directed toward the center point O of the grating substrate is also shown. 1 The equivalent light vector n of the second coherent light directed toward the center point O of the grating substrate 2 , and the equivalent light vector e of the first coherent light emitted to the point A on the grating substrate farthest from the center point 1 and the equivalent light vector e of the second coherent light directed toward the center point O of the grating substrate 2 , then, the conditions satisfied by the above compensation angle can be written as:

[0051]

[0052] It is worth noting that according to the above analysis and combined Figure 2 It can be seen that the compensation deflection angle of the compensation device is different according to the corresponding compensation area, and the specific value of the compensation deflection angle is also different. That is to say, the compensation deflection angle data of the compensation device obtained by calculation should actually be a range value, which includes the values ​​of the compensation deflection angles of different compensation areas corresponding to different exposure positions on the grating substrate. However, no matter what the value range of the actual compensation deflection angle calculated according to step S210 and step S220 is, the compensation deflection angle of the compensation device must satisfy its maximum value θ max Satisfy: θ max ≥θ 1 / 2-θ 2 / 2, this is because, θ 1 / 2-θ 2 The calculated value of / 2 is the difference between the grating angle of the exposure position on the grating substrate as the center point and the grating angle of the point farthest from the center point. That is to say, the compensation device must have the ability to compensate the grating angle of the exposure position farthest from the center point on the grating substrate and adjust it back to the same grating angle as the exposure position of the center point on the grating substrate. Therefore, if the maximum value of the range of the actual compensation deflection angle calculated according to step S210 and step S220 is less than θ 1 / 2-θ 2 / 2, the maximum value of the calculated compensation deflection angle should also be set to θ 1 / 2-θ 2 / 2.

[0053] Therefore, the present application provides an interference exposure adjustment method, which is applied to the fiber-optic interference exposure system in the above embodiment, and the system includes: a light guide component, the light guide component includes a first optical fiber and a second optical fiber, the first optical fiber is used to lead out the first coherent light, and the second optical fiber is used to lead out the second coherent light; a grating substrate, the grating substrate has a plurality of exposure positions, the first coherent light and the second coherent light are propagated to the grating substrate through different paths to form an interference exposure field; a compensation device, the compensation device has a plurality of compensation areas, each of the compensation areas corresponds to one of the exposure positions, and each of the compensation areas has a corresponding compensation deflection angle, and the compensation device is arranged on the propagation path of at least one beam of the first coherent light and the second coherent light. The method includes: adjusting the interference solid angle of the first coherent light and the second coherent light at the corresponding exposure position by the compensation deflection angle of the compensation area, so that the grating angles of the gratings formed under the interference exposure field at the exposure positions are all the same. Therefore, the interference solid angle of the incident first coherent light and the second coherent light at the corresponding exposure position can be adjusted through the compensation area on the compensation device, so that the grating obtained by interference exposure under the interference exposure field formed by the first coherent light and the second coherent light has the same grating angle at different exposure positions of the grating substrate, thereby ensuring the consistency and uniformity of the grating angle and ensuring the imaging effect of the grating obtained by the interference exposure system.

[0054] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A fiber-optic interference exposure system, characterized in that: include: A light guide assembly, the light guide assembly comprising a first optical fiber and a second optical fiber, the first optical fiber is used to lead out a first coherent light, and the second optical fiber is used to lead out a second coherent light; A grating substrate, wherein the grating substrate has a plurality of exposure positions, and the first coherent light and the second coherent light are propagated to the grating substrate via different paths to form an interference exposure field; A compensation device, wherein the compensation device has a plurality of compensation areas, each of the compensation areas corresponds to one of the exposure positions, and each of the compensation areas has a corresponding compensation deflection angle, and the compensation device is arranged on a propagation path of at least one beam of the first coherent light and the second coherent light, and is used to adjust the interference solid angle of the first coherent light and the second coherent light at the corresponding exposure position through the compensation area, so that the grating angles of the grating formed under the interference exposure field at the plurality of exposure positions are the same.

2. The optical fiber interference exposure system according to claim 1, characterized in that: The compensation device is a holographic optical element, and the refractive index of each compensation region is set based on its corresponding compensation deflection angle to adjust the interference solid angle of the first coherent light and the second coherent light passing through the holographic optical element.

3. The optical fiber interference exposure system according to claim 1, characterized in that: The compensation device is a curved lens, and the surface curvature of each compensation area is set based on its corresponding compensation deflection angle to adjust the interference solid angle of the first coherent light and the second coherent light passing through the curved lens.

4. The optical fiber interference exposure system according to claim 2 or 3, characterized in that: The placement center of the compensation device is located on the bisector of the angle formed by the light outlet of the first optical fiber, the light outlet of the second optical fiber and the center point of the grating substrate.

5. The optical fiber interference exposure system according to claim 1, characterized in that: The compensation device is a reflector, and the reflectivity of each compensation area is set based on its corresponding compensation deflection angle. The reflector is arranged on the propagation path of the specific coherent light, and is used to change the incident angle of the specific coherent light incident on the exposure plane to adjust the interference solid angle of the first coherent light and the second coherent light, wherein the specific coherent light is the first coherent light or the second coherent light.

6. The optical fiber interference exposure system according to claim 5, characterized in that: The reflection center of the reflector completely coincides with the position of the coherent light spot when the specific coherent light enters the reflector.

7. The optical fiber interference exposure system according to claim 1, characterized in that: The system further includes a mask, which is disposed on an optical path of the first coherent light and the second coherent light emitted from the compensation device to the grating substrate.

8. An interference exposure adjustment method, characterized in that: Applied to any one of claims 1 to 7 of the fiber-optic interference exposure system, the method comprising: The interference solid angle of the first coherent light and the second coherent light at the corresponding exposure position is adjusted by the compensation deflection angle of the compensation area, so that the grating angles of the grating formed under the interference exposure field at the exposure position are all the same.

9. The interference exposure adjustment method according to claim 8, characterized in that: The method further comprises: Acquire first relative position data between a light outlet of the first optical fiber and a center point of the grating substrate, and second relative position data between a light outlet of the second optical fiber and a center point of the grating substrate; The compensation angle is calculated based on the first relative position data and the second relative position data.

10. The interference exposure adjustment method according to claim 9, characterized in that: The maximum value of the compensation angle θ max Satisfy: θ max ≥θ1 / 2-θ2 / 2; Among them, θ1 is the angle formed by the equivalent light vector of the first coherent light and the equivalent light vector of the second coherent light at the center point of the grating substrate, and θ2 is the angle formed by the equivalent light vector of the first coherent light and the equivalent light vector of the second coherent light at the point farthest from the center point on the grating substrate.

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