Exposure device

Abstract

According to the scheme, the utility model discloses an exposure device which is used for exposing a holographic photosensitive material in a waveguide sheet to form a volume holographic grating. The exposure device comprises a light emitting assembly, a prism and a first supporting assembly, the light emitting assembly is used for emitting signal light and reference light to a holographic photosensitive material, the prism is arranged on a light path of the signal light and / or the reference light, the prism is provided with a light inlet face and a light outlet face, and a waveguide sheet is attached to the light outlet face of the prism. Signal light and / or reference light are / is vertically incident from the light incident surface of the prism and are / is emergent from the light emergent surface of the prism to the holographic photosensitive material, and the first supporting assembly is used for supporting the waveguide plate to avoid relative slippage of the waveguide plate and the prism. According to the scheme, the first supporting assembly is adopted to directly support the waveguide sheet instead of indirectly supporting the waveguide sheet through the supporting prism, so that the waveguide sheet can be effectively positioned in the vertical direction, the waveguide sheet is prevented from sliding due to insufficient constraint and self-gravity action, exposure is ensured to always and accurately occur in a design area, and the exposure efficiency is improved. And the product yield is improved.

Description

TECHNICAL FIELD

[0001] The scheme belongs to the technical field of volume holographic grating, and particularly relates to an exposure device for exposing holographic photosensitive material in a waveguide sheet to form a volume holographic grating. BACKGROUND

[0002] In today's rapidly changing technology, augmented reality (AR) technology is gradually penetrating every corner of our lives with its unique charm and is widely used in education, entertainment, medical treatment, industrial manufacturing and other fields. As the core carrier of this technology, the performance of the optical display system of the AR device is directly related to the user experience and market acceptance. At present, the AR display system on the market generally uses a micro display screen and an optical combiner to realize the fusion of virtual information and the real world, and the optical combiner is a combination of prisms, free-form surfaces, BirdBath, optical waveguides and other optical elements, the design of which is particularly critical and is also a key part that distinguishes AR display systems. Among many optical combination schemes, the optical waveguide scheme is considered as the most promising technical path due to its excellent optical effect, compact appearance and good mass production prospects.

[0003] Optical waveguides can be generally divided into two categories: geometric optical waveguides and diffractive optical waveguides. Geometric optical waveguides, also known as array optical waveguides, realize image output and eyebox expansion through array mirror stacking. Although this technology can provide clear image quality, its complex manufacturing process and high cost limit its widespread application in the consumer market. Diffractive optical waveguides mainly include surface relief optical waveguides and volume holographic optical waveguides. Surface relief optical waveguides can be mass-produced by nanoimprint technology, which has attracted great interest from AR optical module manufacturers. They have the advantages of large field of view and large eye movement range, but also bring the problems of light leakage and environmental light rainbow lines. Meanwhile, the related micro-nano processing technology is also a great challenge. The volume holographic grating in the volume holographic optical waveguide is a Bragg grating that will be diffracted with extremely high diffraction efficiency when the incident light wavelength and angle meet the Bragg matching condition, thus having good angle selectivity and wavelength selectivity. These two characteristics can greatly suppress light leakage and environmental light rainbow lines. In addition, volume holographic gratings also have the advantages of high diffraction efficiency, fast development iteration, large-area preparation and low cost.

[0004] Volume holographic optical waveguides are manufactured based on holographic interference technology and are usually exposed by a double-beam interference method. Figure 1As shown, the double-beam interference method mainly uses two coherent lights to irradiate on the holographic photosensitive material at a certain angle. Due to the interference of the two lights, an interference pattern, i.e. a periodic intensity change, is formed in the material, thereby forming a grating in the holographic photosensitive material. Before exposure, the exposure surface of the waveguide sheet containing the holographic photosensitive material is dripped with refractive index matching oil to form an oil film, and then the waveguide sheet is attached to the light exit surface of the prism through the oil film. During the exposure process, the two coherent lights are incident from the two light entrance surfaces of the prism and finally exit from the light exit surface of the prism, thereby exposing the holographic photosensitive material in the waveguide sheet. However, in the existing volume holographic grating exposure device, the waveguide sheet is usually placed in a vertical state, and it only relies on the adsorption of the oil film on the exposure surface to maintain contact with the prism. During the exposure process, the waveguide sheet will produce a continuous micro-displacement under the action of its own gravity, which will cause the two coherent light beams to fail to accurately project onto the preset exposure area, ultimately resulting in the process defect of exposure pattern shift. Practical new type content

[0005] The present scheme aims to overcome at least one of the defects in the prior art, and provides an exposure device for solving the problem of continuous micro-displacement of the waveguide sheet.

[0006] In order to solve the above technical problems, the present scheme proposes an exposure device for exposing the holographic photosensitive material in the waveguide sheet to form a volume holographic grating. The exposure device comprises an light exit assembly, a prism and a first supporting assembly. The light exit assembly is used to emit signal light and reference light onto the holographic photosensitive material. The prism is arranged on the light path of the signal light and / or the reference light. The prism is provided with a light entrance surface and a light exit surface. The waveguide sheet is attached to the light exit surface of the prism. The signal light and / or the reference light is perpendicularly incident from the light entrance surface of the prism and exits from the light exit surface of the prism to the holographic photosensitive material. The first supporting assembly is used to support the waveguide sheet to avoid the relative sliding of the waveguide sheet and the prism.

[0007] The above-mentioned scheme uses the first supporting assembly to directly support the waveguide sheet, rather than indirectly supporting the waveguide sheet by supporting the prism. The waveguide sheet can be effectively positioned in the vertical direction, avoiding the continuous micro-sliding (referred to as sliding sheet) of the waveguide sheet relative to the prism due to insufficient constraint and its own gravity. The relative positional relationship between the waveguide sheet and the prism and the light exit assembly is always consistent during the exposure process, thereby ensuring that the exposure always occurs accurately in the designed area, and improving the product yield.

[0008] The first supporting assembly is preferably provided with a first clamping seat, which is provided with a groove, the opening of the groove is upward, forming a space for accommodating at least the lower part of the waveguide sheet, and the groove is open at least at one end, so that the waveguide sheet is attached to the light-out surface of the prism. The first clamping seat supports the waveguide sheet in a lifting manner, which is easy and effective, and provides great support for the stable attachment of the waveguide sheet to the light-out surface of the prism, and also provides more stable and reliable protection for the optical connection between the waveguide sheet and the prism, so that the exposure device can accurately expose the holographic photosensitive material, and provides a strong guarantee for forming a high-quality volume holographic grating on the waveguide sheet.

[0009] The first clamping seat is preferably provided in a flat plate structure, having a first surface and a second surface opposite to each other; the groove includes a first groove and a second groove, the first groove is open at one end and extends to the first surface, and the second groove is open at one end and extends to the second surface, the cross-sectional shape and / or size of the first groove and the second groove are different, so as to accommodate waveguide sheets of different specifications. The design of the double-sided groove can improve the utilization rate of the first clamping seat, and the first groove or the second groove can be selectively used during exposure according to the specification of the waveguide sheet.

[0010] The groove is preferably provided with a first side wall, a second side wall and a groove bottom, the first side wall and the second side wall are respectively connected perpendicularly to the two sides of the groove bottom, so as to accommodate rectangular or right trapezoidal waveguide sheets, meeting the supporting needs of most waveguide sheets. The groove bottom can be parallel to the horizontal plane, or can intersect with the horizontal plane, and the latter is more conducive to the positioning of the waveguide sheet.

[0011] The first supporting assembly is preferably provided with a first support, and the first clamping seat is detachably fixed and installed on the first support for replacement. The first support provides stable support for the first clamping seat, ensuring that the first clamping seat and the waveguide sheet supported thereby are stably positioned during exposure, which helps to reduce exposure errors caused by vibration or displacement, and further improves the stability and consistency of exposure quality.

[0012] The first clamping seat is preferably installed on the side surface of the first support, and the first support is fixedly installed below the prism, and the side surface of the first support on which the first clamping seat is installed is flush with the light-out surface of the prism, so that the waveguide sheet accommodated in the first clamping seat is close to the light-out surface of the prism, facilitating the installation and removal of the first clamping seat on the first support, thereby facilitating the replacement of the first clamping seat.

[0013] The exposure device is preferably provided with a second supporting assembly, which is used for detachably fixing and installing the prism, so as to replace the prism with different positional relationship between the light-in surface and the light-out surface according to the designed exposure angle, ensuring that the light in the light path can be vertically incident from the light-in surface of the prism and directly emitted from the light-out surface of the prism to the waveguide sheet and the holographic photosensitive material at the designed angle.

[0014] The second supporting assembly is preferably provided with a second clamping seat, which comprises a first seat body and a second seat body and is provided with a groove, the groove has an opening facing upward, forming a space for accommodating the lower part of the prism, the groove spans the first seat body and the second seat body, so that the prism is clamped by the locking connection of the first seat body and the second seat body, and the first seat body and / or the second seat body is provided with a notch penetrating the groove, so that the waveguide sheet is attached to the light emitting surface of the prism. The design of the groove not only provides space for the installation of the prism, but also ensures that the upper part of the prism can freely transmit light, meeting the high requirements of the exposure process on light transmission. The design of the groove spanning the two seat bodies enables the prism to be clamped by the locking connection of the first seat body and the second seat body, and this detachable fixed installation method not only facilitates the installation and disassembly of the prism, but also is conducive to the maintenance and replacement of the prism, improving the flexibility and maintainability of the device. The design of the notch greatly facilitates the installation of the first supporting assembly, which is conducive to simplifying the structure of the first supporting assembly.

[0015] The second supporting assembly further comprises a second support, and the first seat body and / or the second seat body is detachably fixed and installed on the second support for replacement. The second support provides stable support for the second clamping seat, ensuring that the second clamping seat and the prism supported thereby are stably positioned during the exposure process, which helps to reduce exposure errors caused by vibration or displacement, and further improves the stability and consistency of exposure quality.

[0016] Compared with the prior art, the present scheme has the following beneficial effects: the first supporting assembly directly supports the waveguide sheet, rather than indirectly supporting the waveguide sheet through the prism, so that the waveguide sheet can be effectively positioned in the vertical direction, avoiding the continuous slight sliding (referred to as sliding sheet) of the waveguide sheet relative to the prism due to insufficient constraint and the gravity of the waveguide sheet itself, ensuring that the relative positional relationship between the waveguide sheet and the prism and the light emitting assembly remains consistent during the exposure process, thereby ensuring that the exposure always occurs accurately in the designed area, and improving the product yield. BRIEF DESCRIPTION OF DRAWINGS

[0017] The drawings are only used for illustrative description and cannot be understood as a limitation on the present scheme; in order to better illustrate the present scheme, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0018] Figure 1 is a schematic diagram of double-beam interference.

[0019] Figure 2 is a schematic diagram of the exposure light path of the holographic photosensitive material in the waveguide sheet.

[0020] Figure 3 is a schematic diagram of the reconstruction light path of the volume holographic grating in the waveguide sheet.

[0021] Figure 4 is a structural schematic diagram of an exposure device with the signal light path and the reference light path configured with the same prism.

[0022] Figure 5 is a structural schematic diagram of an exposure device with the signal light path and the reference light path configured with different prisms.

[0023] Figure 6 is a structural schematic diagram of an exposure device with the signal light path configured with a prism.

[0024] Figure 7 is a structural schematic diagram of an exposure device with the reference light path configured with a prism.

[0025] Figure 8 is a structural schematic diagram of an exposure device from a certain perspective (omitting the light emitting assembly).

[0026] Figure 9 is a structural schematic diagram of an exposure device from another perspective (omitting the light emitting assembly).

[0027] Figure 10 is a sectional view of an exposure device (omitting the light emitting assembly).

[0028] Figure 11 is a partial enlarged view of Figure 10 .

[0029] Figure 12 is an exploded view of an exposure device from a certain perspective.

[0030] Figure 13 is an exploded view of an exposure device from another perspective.

[0031] Figure 14 is a structural schematic diagram of a first support.

[0032] BRIEF DESCRIPTION OF THE DRAWINGS Waveguide sheet 010, holographic photosensitive material 011, volume holographic grating 012, light emitting assembly 100, signal light generator 110, reference light generator 120, prism 200, first support assembly 300, first clamping seat 310, groove 311, groove bottom 3111, first side wall 3112, second side wall 3113, first support 320, second support assembly 400, second clamping seat 410, first seat body 411, second seat body 412, recess 413, notch 414, second support 420. DETAILED DESCRIPTION

[0033] In order to enable those skilled in the art to better understand the present scheme, the present scheme will be further described in detail below in conjunction with specific embodiments.

[0034] Figures 2-3Exposure light path and reconstruction light path of volume holographic grating in waveguide sheet are shown. Volume holographic grating is made of holographic photosensitive material 011, signal light and reference light are irradiated on holographic photosensitive material 011 to form double-beam interference, as shown in Figure 2 Holographic photosensitive material 011 records interference fringe distribution in the form of refractive index change distribution, which corresponds to the required grating structure, i.e. volume holographic grating 012. Reconstruction light path of the obtained volume holographic grating is shown in Figure 3 When light is incident on volume holographic grating 012 along the direction of reference light, diffraction occurs, producing straight-through light L0 (0-order light) and diffracted light L +1 (+1-order light), the direction of straight-through light is consistent with the direction of reference light, and the direction of diffracted light is consistent with the direction of signal light. Therefore, after recording signal light on holographic photosensitive material 011 using reference light to form volume holographic grating 012, signal light can be reconstructed by light whose direction is consistent with the direction of reference light.

[0035] Figures 4-14 Exposure device for exposing holographic photosensitive material 011 in waveguide sheet 010 to form volume holographic grating 012 in waveguide sheet 010 is shown. The exposure device is configured with light emitting assembly 100, prism 200 and first supporting assembly 300, light emitting assembly 100 is used to emit signal light and reference light to holographic photosensitive material 011, prism 200 is used to transmit signal light and / or reference light to enable signal light and / or reference light to be incident on waveguide sheet 010 and its holographic photosensitive material 011 at a designed angle, and first supporting assembly 300 is used to support waveguide sheet 010 to prevent waveguide sheet 010 from slipping relative to prism 200.

[0036] Light emitting assembly 100 includes signal light generator 110 and reference light generator 120, signal light generator 110 is used to emit signal light to holographic photosensitive material 011, and reference light generator 120 is used to emit reference light to holographic photosensitive material 011. Signal light generator 110 and reference light generator 120 can share one light source, which is divided into two beams by a beam splitter, and the two beams are emitted as signal light and reference light through signal light generator 110 and reference light generator 120 respectively. Signal light generator 110 and reference light generator 120 can also have independent light sources, i.e. signal light source and reference light source respectively. In addition to the light source, signal light generator 110 can also be configured with a first lens group to shape the light beam emitted by the light source and emit signal light. The first lens group can shape the light beam emitted by the light source into a parallel light beam, or shape it into a divergent light beam. Reference light generator 120 can also be configured with a second lens group to shape the light beam emitted by the light source and emit reference light. The second lens group can also shape the light beam emitted by the light source into a parallel light beam, or shape it into a divergent light beam.

[0037] Prism 200 can be arranged on the light path of signal light (as shown in Figure 6), or on the light path of the reference light (such as Figure 7 ), or on the light path of both the signal light and the reference light (such as Figures 4-5 ). If the signal light and the reference light are incident into the waveguide sheet 010 and the holographic photosensitive material 011 from the same surface of the waveguide sheet 010, the device can be configured with a prism 200, which is located on both the light path of the signal light and the light path of the reference light, such as Figure 4 . If the signal light and the reference light are incident into the waveguide sheet 010 and the holographic photosensitive material 011 from different surfaces of the waveguide sheet 010, the device can be configured with two prisms 200, one of which is located on the light path of the signal light and the other of which is located on the light path of the reference light, such as Figure 5 ; or the device can be configured with a prism 200, which can be located on the light path of the signal light (such as Figure 6 ) or on the light path of the reference light (such as Figure 7 ).

[0038] The prism 200 is configured with an exit surface and a plurality of entrance surfaces, and the waveguide sheet 010 is attached to the exit surface of the prism 200 (such as Figures 10-11 ). The signal light and / or the reference light is / are perpendicularly incident from the entrance surfaces and then exits from the exit surface and directly enters into the waveguide sheet 010, so that the signal light and / or the reference light can be conveniently incident into the waveguide sheet 010 and the holographic photosensitive material 011 thereof at a design angle, so that the light beams can be reflected and propagated in the waveguide sheet 010 at the design angle during subsequent reproduction. The waveguide sheet 010 is attached to the exit surface of the prism 200 by means of the refractive index matching oil dropped on the surface of the waveguide sheet 010, so that the reflection or refraction of the signal light and / or the reference light at the interface between the waveguide sheet 010 and the prism 200 can be better avoided, and the signal light and / or the reference light can be more ensured to be incident into the waveguide sheet 010 and the holographic photosensitive material 011 thereof at the design angle. If the prism 200 is located on both the light path of the signal light and the light path of the reference light, the prism 200 is configured with at least two entrance surfaces, one of which is for the signal light and the other of which is for the reference light, such as Figure 4 . If the prism 200 is located only on the light path of the signal light or only on the light path of the reference light, the prism 200 can be configured with one entrance surface, which is for the light on the light path, such as Figures 5-7 .

[0039] The first supporting assembly 300 can be arranged below the waveguide sheet 010 to support the waveguide sheet 010 from the bottom, or above or beside the waveguide sheet 010 to support the waveguide sheet 010 by clamping, so as to avoid the waveguide sheet 010 from sliding downward due to its own gravity, ensure the relative position relationship between the waveguide sheet 010 and the prism 200 and the light emitting assembly 100 to be consistent during the exposure process, and ensure the exposure to occur in the designed area accurately, thereby improving the product yield.

[0040] As shown in Figures 8-14 The first supporting assembly 300 can be arranged with a first clamping seat 310, and the first clamping seat 310 is arranged with a groove 311. The groove 311 has an opening upward to form a space for accommodating at least the lower part of the waveguide sheet 010, so as to support the waveguide sheet 010 from the bottom. At least one end of the groove 311 is open, that is, the groove 311 can be an open groove 311 with both ends open, or a semi-closed groove 311 with one end open and the other end closed, so as to expose one surface of the waveguide sheet 010 installed in the groove 311, and facilitate the waveguide sheet 010 to be attached to the light emitting surface of the prism 200 through the open end. The first clamping seat 310 has a simple structure, and can support the waveguide sheet 010 easily and effectively by lifting, thereby providing great support for the waveguide sheet 010 to be stably attached to the light emitting surface of the prism 200, and providing more stable and reliable guarantee for the optical connection between the waveguide sheet 010 and the prism 200, so that the exposure device can accurately expose the holographic photosensitive material 011, and provide strong guarantee for forming high-quality volume holographic grating 012 on the waveguide sheet 010.

[0041] The first holder 310 can be configured as a flat plate structure with a first surface and a second surface opposite to each other. The groove 311 can be configured as a first groove 311 and a second groove 311, one end of the first groove 311 being open and extending to the first surface, and one end of the second groove 311 being open and extending to the second surface. Two sub-grooves 311 with different cross-sectional shapes and / or sizes are formed on both sides of the first holder 310, so as to accommodate waveguide sheets 010 of different specifications, improve the utilization rate of the first holder 310, and selectively use the first groove 311 or the second groove 311 during exposure according to the specification of the waveguide sheet 010. The device can also be equipped with multiple first holders 310, and the cross-sectional shapes and / or sizes of the grooves 311 of these first holders 310 are different, so as to support waveguide sheets 010 of different specifications and meet the exposure needs of waveguide sheets 010 of more specifications. The other end of the first groove 311 and the other end of the second groove 311 can be through, forming an open stepped groove 311, or can be separated, forming two semi-closed sub-grooves 311. In comparison, the open groove 311 and the open stepped groove 311 greatly facilitate the process of fitting the waveguide sheet 010 with the light exit surface of the prism 200, improve the accuracy and efficiency of fitting, and are more convenient for the installation and removal of the waveguide sheet 010 on the prism 200 and the first holder 310.

[0042] The cross-sectional profile of the groove 311 matches the waveguide sheet 010 or the lower profile thereof. The waveguide sheet 010 is usually configured as a rectangle, so the groove 311 can be configured as a right-angled groove 311 with a rectangular or trapezoidal cross-sectional profile. Specifically, as shown in Figure 14 The right-angled groove 311 has a first side wall 3112, a second side wall 3113, and a groove bottom 3111. The first side wall 3112 and the second side wall 3113 are respectively connected perpendicularly to both sides of the groove bottom 3111, and can accommodate waveguide sheets 010 with two adjacent angles being right angles, such as rectangular and right-angled trapezoidal waveguide sheets 010. The groove bottom 3111 of the right-angled groove 311 can be parallel to the horizontal plane, or can intersect the horizontal plane. In comparison, the latter is more conducive to the positioning of the waveguide sheet 010.

[0043] The first support assembly 300 can also be configured with a first support 320 for fixing the first holder 310. The first support 320 provides stable support for the first holder 310, ensures stable positioning of the first holder 310 and the waveguide sheet 010 supported thereby during exposure, helps to reduce exposure errors caused by vibration or displacement, and further improves the stability and consistency of exposure quality. The first holder 310 is detachably fixed and installed on the first support 320, so as to be replaced by a first holder 310 with different cross-sectional shapes and / or sizes of the groove 311 according to the specification of the waveguide sheet 010. Specifically, as shown in Figure 12As shown, the first holder 310 can be mounted on the side of the first support 320, and the first support 320 can be fixedly mounted below the prism 200. The side of the first support 320 on which the first holder 310 is mounted is flush with the light exit surface of the prism 200, so that the waveguide sheet 010 accommodated in the first holder 310 is close to the light exit surface of the prism 200, facilitating the installation and removal of the first holder 310 on the first support 320, thereby facilitating the replacement of the first holder 310.

[0044] The exposure device can further be provided with a second supporting assembly 400 for detachably fixing and mounting the prism 200, so as to replace the prism 200 with different positional relationship between the light entrance surface and the light exit surface according to the designed exposure angle, ensuring that the light in the light path can be vertically incident from the light entrance surface of the prism 200 and directly emitted from the light exit surface of the prism 200 to the waveguide sheet 010 and the holographic photosensitive material 011 at the designed angle.

[0045] The second supporting assembly 400 can be provided with a second holder 410, as shown in FIG. 4B. Figures 12-13 As shown, the first holder 310 includes a first seat body 411 and a second seat body 412, and is provided with a recess 413. The slot of the recess 413 is upward, forming a space for accommodating the lower part of the prism 200, ensuring that the upper part of the prism 200 can transmit light. The recess 413 spans the first seat body 411 and the second seat body 412, so as to clamp the prism 200 through the locking connection of the first seat body 411 and the second seat body 412, realizing the detachable fixing and mounting of the prism 200. The second holder 410 is provided with a notch 414 on one side, so that the first holder 310 and the waveguide sheet 010 supported thereby can contact the light exit surface of the prism 200 through the notch 414, thereby facilitating the adhesion of the waveguide sheet 010 to the light exit surface of the prism 200. The notch 414 can be arranged on one side of the first seat body 411, or on one side of the second seat body 412, or span the first seat body 411 and the second seat body 412.

[0046] The second supporting assembly 400 can further be provided with a second support 420 for fixing the second holder 410. The second support 420 provides stable support for the second holder 410, ensuring that the second holder 410 and the prism 200 supported thereby are stably positioned during the exposure process, which helps to reduce exposure errors caused by vibration or displacement, and further improves the stability and consistency of exposure quality. The second holder 410 is detachably fixed and mounted on the second support 420, so as to replace the prism 200 with different positional relationship between the light entrance surface and the light exit surface according to the designed exposure angle.

[0047] Obviously, the above embodiments of the present application are merely exemplary but not intended to limit the embodiments of the present application. Based on the above description, any other variations or modifications of the embodiments can be made by those skilled in the art without departing from the spirit and principles of the present application. It is to be understood that the present application is not limited to the above-described embodiments but covers any modifications or variations thereof within the spirit and principles of the present application.

Claims

1. An exposure device for exposing a holographic photosensitive material in a waveguide sheet to form a volume holographic grating, characterized in that the exposure device comprises a light emitting assembly for emitting a signal light and a reference light to the holographic photosensitive material, a prism provided in a light path of the signal light and / or the reference light, the prism being provided with an entrance surface and an exit surface, the waveguide sheet being attached to the exit surface of the prism, the signal light and / or the reference light being perpendicularly incident on the entrance surface of the prism and emitted from the exit surface of the prism to the holographic photosensitive material, and a first supporting assembly for supporting the waveguide sheet to avoid relative sliding between the waveguide sheet and the prism.

2. The exposure device according to claim 1, characterized in that the first supporting assembly comprises a first holder provided with a groove, the groove having an opening upward to form a space for accommodating at least a lower portion of the waveguide sheet, and the groove being open at least at one end to allow the waveguide sheet to be attached to the exit surface of the prism.

3. The exposure device according to claim 2, characterized in that the first holder is provided in a flat plate structure having a first surface and a second surface opposite to each other, the groove comprises a first groove open at one end and extending to the first surface, and a second groove open at one end and extending to the second surface, and the first groove and the second groove are different in cross-sectional shape and / or size to accommodate waveguide sheets of different specifications.

4. The exposure device according to claim 2, characterized in that the groove has a first side wall, a second side wall and a groove bottom, the first side wall and the second side wall being respectively connected perpendicularly to two sides of the groove bottom to accommodate a rectangular or right trapezoidal waveguide sheet.

5. The exposure device according to claim 4, characterized in that the groove bottom intersects with a horizontal plane.

6. The exposure device according to any one of claims 2 to 5, characterized in that the first supporting assembly further comprises a first support, and the first holder is detachably fixed to the first support to be replaced.

7. The exposure device according to claim 6, characterized in that the first holder is mounted on a side surface of the first support, the first support is fixedly mounted below the prism, and the side surface of the first support on which the first holder is mounted is flush with the exit surface of the prism to allow the waveguide sheet accommodated in the first holder to be close to the exit surface of the prism.

8. The exposure device according to any one of claims 1 to 5, characterized in that the exposure device further comprises a second supporting assembly for detachably fixing the prism.

9. The exposure device according to claim 8, characterized in that the second supporting assembly comprises a second holder, the second holder comprises a first seat body and a second seat body, and is provided with a recess, the recess having an opening upward to form a space for accommodating a lower portion of the prism, and the recess spanning the first seat body and the second seat body to clamp the prism by a locking connection between the first seat body and the second seat body, and the first seat body and / or the second seat body is provided with an aperture penetrating the recess to allow the waveguide sheet to be attached to the exit surface of the prism. ​ ​ ​ ​ ​ ​ ​ ​ ​ 10. The exposure apparatus according to any one of claims 1 to 9, wherein the second support assembly further includes a second bracket, and the first seat and / or the second seat is detachably fixed to the second bracket so as to be replaced.

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