Manufacturing method of large-area grating

Abstract

According to the manufacturing method of the large-area grating, the grating device comprises a base sheet and a grating, the method comprises the steps that a laser device is used for emitting a detection laser beam, the detection laser beam penetrates through a first substrate and irradiates a second grating, a diffraction laser beam is generated, and the diffraction laser beam penetrates through the first substrate in a transmission mode so as to enter air; the light entering the air is reflected to a target plate through a reflector, a diffraction laser beam is received on the target plate, and the center of a laser spot is marked on the target plate and marked as a point P; translating the grating device to form a P'point; if the P'point and the P point do not coincide, the grating lines of the first grating and the second grating are not parallel, the grating device horizontally rotates the first substrate in a glued uncured state, and the laser spot on the target plate is observed until the P 'point and the P point coincide, other devices do not need to be added in a holographic recording light path, the technology is simple, and the cost is low.

Description

Technical Field

[0001] The invention belongs to the technical field of optical element manufacturing methods, and in particular relates to a method for manufacturing a large-area grating. Background Art

[0002] Holographic gratings are the core components of new HUDs and head-mounted displays. They have been used by companies such as BAE to develop HUDs and head-mounted displays. The optical systems of HUDs and head-mounted displays containing holographic gratings are compact, light, and have large exit pupils, which have great display performance advantages. Large-area holographic gratings are key components in HUDs, and the parallelism of the holographic grating lines is very high. The production of large-area holographic gratings is limited by the aperture of the holographic recording optical system. Therefore, the method of splicing two holographic gratings is considered to produce large-area holographic gratings, and the gluing alignment method is used to ensure the parallelism of the holographic grating lines.

[0003] In the prior art, the method of multiple exposure stitching alignment is generally used, which requires adding piezoelectric ceramic feedback in the holographic recording optical path, adjusting and observing the moiré fringes, and repeatedly exposing and developing the same holographic dry plate, which is not suitable for recording materials such as silver halide and gelatin. This technology is complex, difficult, has a low success rate, and is costly. Summary of the invention

[0004] In view of this, the method for making a large-area grating provided by the present invention reduces costs by making two gratings separately, splicing them into a large-area grating by gluing, and ensuring the parallelism of the holographic grating lines by alignment.

[0005] A method for manufacturing a large-area grating is suitable for manufacturing and testing a grating device on an optical display device or a spectroscopic device. The grating device comprises a substrate and a grating. The substrate comprises a first substrate and a second substrate of the same size. The grating comprises a first grating and a second grating. The sum of the lengths of the first grating and the second grating is less than or equal to the length of the substrate, or the sum of the lengths of the first grating and the second grating is less than or equal to the length of the first substrate or the second substrate. The first grating is arranged on one end of the bottom surface of the first substrate, and the second grating is arranged on the top surface of the second substrate aligned with the end corresponding to the first grating. The first substrate and the second substrate are glued together to form the grating device. The manufacturing method comprises:

[0006] Using a laser to emit a detection laser beam, the laser beam passes through the first substrate at a preset angle and illuminates the second grating to generate a diffracted laser beam, and the diffracted laser beam passes through the first substrate in a transmission manner, thereby entering the air;

[0007] The light entering the air is reflected by the reflector to the target plate, where the diffracted laser beam is received. The center of the laser spot is marked on the target plate, which is recorded as point P.

[0008] The grating device is translated to make the detection laser beam illuminate the first grating and generate a diffracted laser beam. The diffracted laser beam passes through the first substrate and enters the air again. The light is reflected to the target plate by the reflector, and the center of the laser spot is marked on the target plate, which is recorded as point P'.

[0009] If point P' and point P do not overlap, it is considered that the grating lines of the first grating and the second grating are not parallel. Then, the grating device is horizontally rotated on the first substrate in the uncured state of the glue, and the laser spot on the target plate is observed until point P' and point P overlap.

[0010] The technical beneficial effects of the present invention are:

[0011] The present invention adopts the method of gluing and alignment to realize the production of large-area holographic gratings. Holographic gratings of two regions can be made separately, and then spliced ​​into a large-area holographic grating by gluing, and the holographic grating lines of the two regions are made parallel to each other by alignment. Since the holographic gratings are made separately, the production success rate is greatly improved. This method does not need to add other devices in the holographic recording optical path, and the technology is simple and the cost is low. The present invention adopts the method of gluing and alignment to realize the production of large-area holographic gratings. Holographic gratings of two regions can be made separately, and then spliced ​​into a large-area holographic grating by gluing, and the holographic grating lines of the two regions are made parallel to each other by alignment. Since the holographic gratings are made separately, the production success rate is greatly improved. This method does not need to add other devices in the holographic recording optical path, and the technology is simple and the cost is low. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0013] Figure 1 is a schematic diagram of a first glass plate and a first holographic grating;

[0014] Figure 2 is a schematic diagram of a second glass plate and a second holographic grating;

[0015] Figure 3 is a schematic diagram of stacking the first and second glass plates;

[0016] Figure 4 Schematic diagram of laser beam test;

[0017] Figure 5 This is a schematic diagram of gluing alignment.

[0018] Among them, 101, the first substrate; 102, the first grating; 103, the second substrate; 104, the second grating; 105, the optical glue; 201, the illumination light at the use angle; 202, the diffraction light at the use angle; 203, the detection laser beam; 204, the diffracted laser beam; 205, the diffracted laser beam parallel to the surface of the optical platform after adjustment by the reflector; 206, the laser; 207, the reflector; 208, the target plate. DETAILED DESCRIPTION

[0019] The embodiments of the present disclosure are described in detail below with reference to the accompanying drawings.

[0020] The following describes the embodiments of the present disclosure through specific examples, and those skilled in the art can easily understand other advantages and effects of the present disclosure from the contents disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, rather than all of the embodiments. The present disclosure can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present disclosure. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present disclosure.

[0021] It should be noted that various aspects of the embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on the present disclosure, it should be understood by those skilled in the art that an aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects described herein can be used to implement the device and / or practice the method. In addition, other structures and / or functionalities other than one or more of the aspects described herein can be used to implement this device and / or practice this method.

[0022] like Figures 1 to 5The method for manufacturing a large-area grating shown is suitable for manufacturing and testing a grating device on an optical display device or a spectrometer. The grating device includes a substrate and a grating. The substrate includes a first substrate 101 and a second substrate 103 of the same size. The grating or holographic grating includes a first grating 102 and a second grating 104. The sum of the lengths of the first grating 102 and the second grating 104 is less than or equal to the length of the substrate, or the sum of the lengths of the first grating 102 and the second grating 104 is less than or equal to the length of the first substrate 101 or the second substrate 103. The first grating 102 is arranged on one end of the bottom surface of the first substrate 101 in an aligned manner, for example, by bonding with optical glue 105, and the second grating 104 is arranged on the top surface of the second substrate 103 in an aligned manner with the end corresponding to the first grating 102. See Figure 1 The first grating 102 is on the left side of the first substrate 101, see Figure 2 The second grating 104 is on the right side of the second substrate 103. The first substrate 101 and the second substrate 103 are glued together to form a grating device, and the two gratings are located in the middle to form a holographic grating. The manufacturing method includes:

[0023] Using a long-wave test, a laser 206 is used to emit a detection laser beam 203, which passes through the first substrate 101 and irradiates the second grating 104 at a preset angle, the preset angle range is 10°-60°, and generates a diffracted laser beam 204. The diffracted laser beam 204 passes through the first substrate 101 in a transmission manner, thereby entering the air and forming a diffracted laser beam 204;

[0024] The light entering the air passes through the reflector 207, forming a diffracted laser beam 205 that is adjusted by the reflector 207 and parallel to the surface of the optical platform. The diffracted laser beam 205 that is adjusted by the reflector 207 and parallel to the surface of the optical platform is received by the target plate 208, and the center of the laser spot is marked on the target plate 208, which is recorded as point P. The test using a long wave at a non-use angle: The holographic grating in the HUD is generally a holographic waveguide grating. When the illumination light illuminates the second grating 104 at the use angle, the diffracted light will be totally reflected and transmitted at a large angle in the glass plate, and cannot enter the air, making it inconvenient to be observed. Therefore, a laser 206 with a wavelength greater than the illumination light is used to emit a detection laser beam 203 at an appropriate angle greater than the use angle to illuminate the second grating 104, so that the diffracted laser beam 204 can pass through the first substrate 101 and enter the air, making it easier to be observed. It should be pointed out that when the illumination light 201 at the use angle is incident, the diffracted light 202 at the use angle cannot be diffracted to the reflector 207.

[0025] The grating device is translated so that the detection laser beam 203 irradiates the first grating 102 and generates a diffracted laser beam 204. The diffracted laser beam 204 passes through the first substrate 101 and enters the air again. The light is reflected to the target plate 208 by the reflector 207. The center of the laser spot is marked on the target plate 208, which is recorded as point P'.

[0026] like Figure 5 As shown, if point P' and point P do not overlap, it is considered that the grating lines of the first grating 102 and the second grating 104 are not parallel. Then, the grating device is in an uncured state of bonding, the first substrate is horizontally rotated, and the laser spot on the target plate 208 is observed until point P' and point P overlap. Preferably, different types of grating devices correspond to different distances of the target plate 208. For example, the overlap accuracy of point P' and point P is related to the placement position of the target plate. The farther the target plate 208 is, the higher the correction accuracy.

[0027] In the above description, the first substrate and the second substrate are made of glass or other transparent materials, and the wavelength of the detection laser beam 203 emitted by the laser 206 is 650 nm.

[0028] Example

[0029] The following is an example of a holographic grating element for a head-up display. The element has two layers of glass plates glued together, the holographic grating is in the glued layer, the type of holographic grating is a volume holographic waveguide grating, the material of the glass plate is fused quartz, and the recording medium of the holographic grating is dichromated gelatin.

[0030] (1) manufacturing a first holographic grating on a first glass substrate, wherein the first holographic grating is located below and to the right of the first glass substrate; manufacturing a second holographic grating on a second glass substrate, wherein the second holographic grating is located above and to the left of the second glass substrate;

[0031] (2) fixing the second glass substrate to the optical platform by using a magnetic stand to press against the side of the second glass substrate so that it cannot translate or rotate;

[0032] (3) Place the first glass substrate on top of the second glass substrate, fill the space between the second glass substrate and the first glass substrate with optical epoxy resin glue, and clamp the combination of the first glass substrate and the second glass substrate on a horizontally movable guide rail. Before the optical epoxy resin glue is cured, complete (4) to

[0033] (9) Operation;

[0034] (4) Use a laser to emit a detection laser beam, which passes through the first glass substrate at an appropriate angle, illuminates the second holographic grating, and generates a diffracted laser beam. The diffracted laser beam passes through the first glass substrate and enters the air. It should be noted that the holographic grating in the HUD is generally a holographic waveguide grating. When the illumination light illuminates the second holographic grating at a use angle, the diffracted light will be totally reflected and transmitted at a large angle in the glass plate, and cannot enter the air, making it inconvenient to be observed. Therefore, a laser with a wavelength greater than the illumination light is used to emit a detection laser beam at an appropriate angle greater than the use angle to illuminate the second holographic grating, so that the diffracted laser beam can pass through the first substrate and enter the air, making it easier to be observed. In this embodiment, the illumination light angle is 0°, the illumination light wavelength is 532nm, the laser wavelength is 650nm, the detection laser beam illuminates the first glass substrate at an incident angle of 60°, passes through the first glass substrate, illuminates the second holographic grating, and the diffracted laser beam passes through the first glass substrate and enters the air;

[0035] (5) inserting a reflector into the transmission optical path of the diffracted laser beam and adjusting the reflector so that the diffracted laser beam is parallel to the surface of the optical platform;

[0036] (6) Set up a target plate 10 meters away from the test point, i.e., where the detection laser beam illuminates the holographic grating, to receive the diffracted laser beam, and mark the center of the laser spot on the target plate, which is recorded as point P;

[0037] (7) Move the guide rail and translate the first glass substrate and the second glass substrate combination so that the detection laser beam irradiates the first holographic grating to generate a diffracted laser beam. The diffracted laser beam passes through the first glass substrate and enters the air. The diffracted laser beam is irradiated onto the target plate through the reflector, and the center of the laser spot is point P'. If the grating lines of the first holographic grating and the second holographic grating are not parallel, then point P' and point P do not coincide;

[0038] (8) Horizontally rotating the first glass substrate while observing the laser spot on the target plate to make point P' coincide with point P;

[0039] (9) After 24 hours, the epoxy resin glue is cured, and the production of the large-area holographic grating is completed.

[0040] The above are only specific embodiments of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present disclosure should be included in the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be based on the protection scope of the claims.

Claims

1. A method for manufacturing a large-area grating, which is suitable for manufacturing and testing grating devices on optical display devices or spectrometers, wherein the grating device comprises a substrate and a grating, and is characterized in that: The substrate sheet includes a first substrate and a second substrate of the same size, the grating includes a first grating and a second grating, the sum of the lengths of the first grating and the second grating is less than or equal to the length of the substrate sheet, or the sum of the lengths of the first grating and the second grating is less than or equal to the length of the first substrate or the second substrate, wherein the first grating is aligned with one end of the bottom surface of the first substrate, the second grating is aligned with one end of the top surface of the second substrate corresponding to the first grating, and the first substrate and the second substrate are glued together to form a grating device, and the manufacturing method includes: Using a laser to emit a detection laser beam, the laser beam passes through the first substrate at a preset angle and illuminates the second grating to generate a diffracted laser beam, and the diffracted laser beam passes through the first substrate in a transmission manner, thereby entering the air; The light entering the air is reflected by the reflector to the target plate, which receives the diffracted laser beam and marks the center of the laser spot on the target plate, which is recorded as point P. The grating device is translated to make the detection laser beam illuminate the first grating and generate a diffracted laser beam. The diffracted laser beam passes through the first substrate and enters the air again. The light is reflected to the target plate by the reflector, and the center of the laser spot is marked on the target plate, which is recorded as point P'. If point P' and point P do not overlap, it is considered that the grating lines of the first grating and the second grating are not parallel. Then, the grating device is horizontally rotated on the first substrate in the uncured state of the glue, and the laser spot on the target plate is observed until point P' and point P overlap.

2. The method according to claim 1, characterized in that: Different types of grating devices correspond to target plate positions at different distances.

3. The method according to claim 1, characterized in that: The first substrate and the second substrate are made of glass.

4. The method according to claim 1, characterized in that: The wavelength of the detection laser beam emitted by the laser is 650nm.

5. The method according to claim 1, characterized in that: The preset angles range from 10° to 60°.

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