Exposure apparatus for display screen production

Abstract

The application discloses a kind of exposure equipment for display screen production, it is related to the technical field of display screen production exposure, including detection platform, which is equipped with sliding support plate, initial position and exposure position are set on detection platform;Flattening plate is assembled on detection platform and is located on the movement path between initial position and exposure position, and the flattening plate is in contact with substrate for flattening substrate;Support panel is provided with a plurality of negative pressure through holes, a plurality of the negative pressure through holes are communicated with main air pipe, and the physical flattening of flattening plate is combined with negative pressure adsorption, to forcibly eliminate substrate warping, fundamentally avoid the quality problems such as pattern misplacement and defocus caused by uneven substrate during exposure, and the entire process is completely completed by equipment mechanical linkage automatically from putting into substrate to completing exposure and taking plate.Flattening action itself is used as power source, to trigger subsequent adsorption and positioning action, to ensure that the position of substrate in exposure position is accurate and consistent, to improve the consistency and yield of product.

Description

Technical Field

[0001] This invention relates to the field of display screen exposure technology, and in particular to an exposure device for display screen production. Background Technology

[0002] During transport and processing, substrates undergo minute deformations or warping. Exposure machines identify "alignment marks" distributed on the substrate to precisely overlay the mask pattern onto existing circuit layers. This process is called "overlay." Once the substrate warps or deforms, the spatial positions of these alignment marks change slightly in three dimensions. The substrate deformation means its surface is no longer a perfect focal plane. During exposure, only the highest or lowest point of deformation can be precisely focused, while other areas remain out of focus. The newly exposed pattern layer cannot be precisely aligned with the old pattern layer, causing incorrect circuit connections, short circuits, or open circuits between layers, resulting in drastic fluctuations in yield within and between batches, and disrupting stable production. Summary of the Invention

[0003] The purpose of this invention is to provide an exposure device for display screen production, which combines physical flattening with negative pressure adsorption to forcibly eliminate substrate warping. This fundamentally avoids quality problems such as pattern misalignment and defocusing caused by uneven substrates during exposure. From substrate placement to substrate removal after exposure, the entire process is fully automated through mechanical linkage. The flattening action itself serves as a power source, triggering subsequent adsorption and positioning actions to ensure precise and consistent substrate positioning at the exposure location, thereby improving product consistency and yield.

[0004] To achieve the above objectives, the present invention provides the following technical solution: an exposure apparatus for display screen production, comprising: The testing platform is equipped with a sliding support plate. An initial position and an exposure position are set on the testing platform. The support plate is used to transport the substrate of the display screen back and forth between the initial position and the exposure position. The pressure plate is mounted on the detection platform and is located on the moving path between the initial position and the exposure position. The pressure plate can be raised and lowered, and the pressure plate contacts the substrate to flatten the substrate. The support panel is provided with several negative pressure through holes, which are connected to the main air pipe. The main air pipe is connected to the negative pressure pump. The support panel is connected to the support plate through an elastic telescopic rod. A valve, installed inside the main air pipe, is rotated to control the opening or closing of the main air pipe. A switch controlling the rotation of the valve is connected to a rotating shaft, which is mounted on a support panel. The lifting and lowering of the pressure plate causes the support panel to lift and lower synchronously. A ratchet on the support panel is connected to the rotating shaft, driving the rotating shaft during one lifting and lowering process. During one lifting and lowering process, the support panel drives the rotating shaft and the switch to rotate synchronously to open the main air pipe. During the next lifting and lowering process, the support panel rotates synchronously through the rotating shaft and the switch to close the main air pipe. This allows the pressure plate to open the main air pipe while lowering and flattening the substrate of the display screen as it moves to the exposure position. Negative pressure is used to hold the substrate of the display screen to maintain flatness.

[0005] As an optional implementation, the pressure plate is connected to the cylinder / hydraulic cylinder on the testing platform, and the area of ​​the pressure plate is larger than the upper part of the support panel.

[0006] As an optional implementation, the ratchet component includes an upper plate, a lower plate, an upper ratchet seat, and a lower ratchet seat. The upper ratchet seat is fixed on the upper plate, and the lower ratchet seat is fixed on the lower plate. The upper plate and the lower plate are connected to the support rod on the support panel. The tooth grooves between the upper ratchet seat and the lower ratchet seat are staggered and form a control channel.

[0007] As an optional implementation, the rotating shaft includes an upper rotating shaft and a lower rotating shaft, which are connected by a ratchet assembly. The upper rotating shaft passes through the lower plate and the lower ratchet seat, and a side rod fixed to the top of the upper rotating shaft is located in the control channel.

[0008] As an optional implementation, the ratchet assembly includes a convex ring, an upper tooth, and a lower tooth. The convex ring has a "T" shaped cross-section. The convex ring is fixed on the top of the rotating lower shaft and is engaged in the annular groove of the rotating upper shaft, so as to keep the rotating upper shaft and the rotating lower shaft coaxial. The upper tooth is inserted into the groove at the bottom of the rotating upper shaft by a spring, and the lower tooth is fixed on the top of the rotating lower shaft. The upper and lower teeth are interlocked and arranged in a ring shape.

[0009] As an optional implementation, the lower rotating shaft is also connected to the positioning component on the support plate and the ratchet component on the detection platform.

[0010] As an optional implementation, the positioning component includes a turntable, a clamping rod, and an inner rod. The inner rod is fixed on the lower rotating shaft, and the top end of the inner rod passes through the upper rotating shaft and is connected to a spring. The turntable is sleeved on the inner rod, and the two rotate synchronously. The turntable can slide on the inner rod. Several arc grooves are provided on the turntable, and one end of the clamping rod passes through the arc groove. The support panel has a strip groove, the clamping rod passes through the strip groove and is locked in the strip groove, and the rotation of the turntable drives the clamping rod to move back and forth along the strip groove.

[0011] As an optional implementation, the top groove of the clamping rod is connected to the clamping head by a spring, and the movement of the clamping head is used to position the substrate.

[0012] As an optional implementation, the second ratchet assembly includes a rack, ratchet, baffle, and ring. The ring is mounted on the rotating lower shaft, the rack is set on the detection platform, the ratchet is hinged to the ring, the ratchet is also connected to the ring via a spring, and the baffle is fixed to the ring to limit the rotation direction of the ratchet.

[0013] As an optional implementation, when the ratchet moves from the initial position to the exposure position, the upper rotating shaft drives the lower rotating shaft to rotate, the lower rotating shaft opens the valve and the chuck clamps the substrate, and when the ratchet moves back from the exposure position to the initial position, the lower rotating shaft rotates in the opposite direction to close the valve and the chuck releases the substrate.

[0014] The technical effects and advantages of this invention are as follows: 1. The combination of physical flattening by the platen and negative pressure adsorption forcibly eliminates substrate warping and locks it in a flat state, fundamentally avoiding quality problems such as pattern misalignment and defocusing caused by uneven substrate during exposure.

[0015] 2. From placing the substrate to removing it after exposure, the entire process is fully automated by the mechanical linkage of the equipment. The flattening action itself serves as a power source, triggering subsequent adsorption and positioning actions. The single action of the pressing plate downward pressure is transformed into two major functions: controlling the opening and closing of the valve and driving the positioning mechanism, without the need for additional sensors or complex electronic control programs.

[0016] 3. While flattening, the mechanical transmission drives the clamping rod to simultaneously center and position the substrate, ensuring that the substrate is accurately and consistently positioned at the exposure location, thus improving product consistency and yield. Attached Figure Description

[0017] Figure 1 This is an overall isometric view of the present invention; Figure 2 This is a structural diagram of the support plate and support panel of the present invention; Figure 3 This is a partial bottom view of the present invention; Figure 4 This is a structural diagram showing the separation of the positioning component and the supporting panel of the present invention; Figure 5 This is a structural diagram of the ratchet component and ratchet assembly of the present invention; Figure 6 This is a structural diagram of the ratchet assembly of the present invention. Figure 7 This is a cross-sectional view of the upper gear and rotating upper shaft of the present invention; Figure 8 This is a structural diagram of the ratchet assembly of the present invention.

[0018] In the picture: 1. Testing platform; 2. Support plate; 3. Pressure plate; 4. Support panel; 41. Negative pressure through hole; 42. Main air pipe; 5. Valve; 51. Switch; 52. Rotating shaft; 521. Upper rotating shaft; 522. Lower rotating shaft; 6. Ratchet assembly; 61. Upper plate; 62. Lower plate; 63. Upper ratchet seat; 64. Lower ratchet seat; 7. Ratchet assembly one; 71. Convex ring; 72. Upper tooth; 73. Lower tooth; 8. Ratchet assembly two; 81. Rack; 82. Ratchet; 83. Baffle; 84. Ring body; 9. Positioning assembly; 91. Turntable; 92. Clamping rod; 921. Chuck; 93. Inner rod; 10. Side rod. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] participate Figures 1-8 An exposure apparatus for display screen production, comprising: The testing platform 1 is equipped with a sliding support plate 2. The testing platform 1 is set with an initial position and an exposure position. The support plate 2 is used to transport the substrate of the display screen to move back and forth between the initial position and the exposure position. The support plate 2 is driven to move back and forth by a linear motor. The pressure plate 3 is mounted on the detection platform 1 and is located on the moving path between the initial position and the exposure position. The pressure plate 3 can be raised and lowered. The pressure plate 3 contacts the substrate to flatten the substrate. The pressure plate 3 is connected to the cylinder / hydraulic cylinder on the detection platform 1, and the area of ​​the pressure plate 3 is larger than the upper part of the support panel 4.

[0021] The support panel 4 is provided with several negative pressure through holes 41, which are connected to the main air pipe 42. The main air pipe 42 is connected to the negative pressure pump. The support panel 4 is connected to the support plate 2 through an elastic telescopic rod. The support panel 4 moves synchronously with the support plate 2. When the support panel 4 moves to the initial position, the display substrate is placed on the support panel 4. When the support panel 4 moves to the bottom of the pressure plate 3, the pressure plate 3 is lowered or raised under the action of the cylinder / hydraulic cylinder. The pressure plate 3 descends and contacts the substrate, thereby flattening the warped part of the substrate. The substrate then adheres to the surface of the support panel 4. The negative pressure generated at the negative pressure through hole 41 is used to hold the substrate, keeping the substrate flat and avoiding the problem of substrate springback and warping.

[0022] The negative pressure through holes 41 are set to be large and sparse in the middle, while the negative pressure through holes 41 closer to the edge are small and dense. Since the warped part of the substrate is mostly near the edge, the adsorption force of the edge area is enhanced, making the flattening transition more natural and the adsorption effect more uniform and reliable. Valve 5 is installed inside the main air pipe 42. The rotation of valve 5 controls the opening or closing of the main air pipe 42. Switch 51, which controls the rotation of valve 5, is connected to shaft 52. Shaft 52 is mounted on support panel 4. The lifting and lowering of pressure plate 3 drives support panel 4 to lift and lower synchronously. Ratchet 6 on support panel 4 is connected to shaft 52. During one lifting and lowering process, shaft 52 is driven. During one lifting and lowering process, support panel 4 drives shaft 52 and switch 51 to rotate synchronously to open main air pipe 42. During the next lifting and lowering process, support panel 4 rotates synchronously through shaft 52 and switch 51 to close main air pipe 42. This allows pressure plate 3 to open main air pipe 42 while lowering and pressing the substrate of display screen flat during the process of support plate 2 moving to exposure position. Negative pressure is used to hold the substrate of display screen to keep it flat.

[0023] The downward force of the pressure plate 3 drives the rotating shaft 52 to rotate, thereby opening the switch 51. At this time, the negative pressure pump can generate negative pressure at the negative pressure through hole 41, allowing the flat substrate to move to the exposure position for exposure treatment, thus avoiding inaccurate positioning of the warped substrate during the exposure process, which would affect the quality of subsequent products.

[0024] The ratchet assembly 6 includes an upper plate 61, a lower plate 62, an upper ratchet seat 63, and a lower ratchet seat 64. The upper ratchet seat 63 is fixed on the upper plate 61, and the lower ratchet seat 64 is fixed on the lower plate 62. The upper plate 61 and the lower plate 62 are connected to the support rod on the support panel 4. The tooth grooves between the upper ratchet seat 63 and the lower ratchet seat 64 are staggered and form a control channel.

[0025] The rotating shaft 52 includes an upper rotating shaft 521 and a lower rotating shaft 522, which are connected by a ratchet assembly 7. The upper rotating shaft 521 passes through the lower plate 62 and the lower ratchet seat 64, and the side rod 10 fixed at the top of the upper rotating shaft 521 is located in the control channel.

[0026] The specific working process of the ratchet component 6 is as follows: During the process of the support panel 4 being pressed down and descending, the upper plate 61, lower plate 62, upper ratchet seat 63, and lower ratchet seat 64 descend synchronously. At this time, the side rod 10 on the rotating upper shaft 521 will contact the tooth groove surface of the upper ratchet seat 63. Since the position of the upper ratchet seat 63 will not rotate, the rotating upper shaft 521 and rotating lower shaft 522 connected to the side rod 10 will rotate. The rotating upper shaft 521 and rotating lower shaft 522 drive the switch 51 to rotate. At this time, the main air pipe 42 is in the open state, and the support panel 4 descends to the lowest position. The substrate pressed by the pressure plate 3 on the support panel 4 is flattened. The negative pressure generated by the negative pressure pump will suck the substrate and keep it flat.

[0027] Furthermore, as the support panel 4 rises, the side rod 10 contacts the lower ratchet seat 64, thereby causing the switch 51 to rotate, which plays a corrective role.

[0028] Since the substrate cannot be squeezed after exposure, ratchet assembly 7 and ratchet assembly 8 are provided to close the main air pipe 42 after exposure.

[0029] The ratchet assembly 7 includes a convex ring 71, an upper tooth 72, and a lower tooth 73. The convex ring 71 has a "T" shaped cross section and is fixed on the top of the rotating lower shaft 522. The convex ring 71 is engaged in the annular groove of the rotating upper shaft 521 to keep the rotating upper shaft 521 and the rotating lower shaft 522 coaxial. The upper tooth 72 is inserted into the groove at the bottom of the rotating upper shaft 521 by a spring, and the lower tooth 73 is fixed on the top of the rotating lower shaft 522. The upper tooth 72 and the lower tooth 73 are staggered and meshed to form a ring.

[0030] The structure of the convex ring 71 ensures that the upper rotating shaft 521 and the lower rotating shaft 522 will not separate, and the two will always remain coaxial. Furthermore, with the upper tooth 72 and the lower tooth 73 in place, the rotation of the upper rotating shaft 521 will drive the lower rotating shaft 522, while the rotation of the lower rotating shaft 522 will not drive the upper rotating shaft 521 to rotate in a unidirectional manner. Specifically, during the rotation of the upper rotating shaft 521 driven by the side rod 10, the upper tooth 72 of the upper rotating shaft 521 pushes the lower tooth 73 to rotate. At this time, the upper rotating shaft 521 and the lower rotating shaft 522 rotate synchronously, thereby driving the switch 51 to rotate in one direction to open the main air pipe 42. During the reverse rotation of the lower rotating shaft 522, the lower tooth 73 rotates towards the inclined surface of the upper tooth 72. At this time, the upper tooth 72 will retract into the groove of the upper rotating shaft 521 and compress the spring, thereby achieving the purpose of rotating the lower rotating shaft 522 while the upper rotating shaft 521 does not rotate. To ensure accurate positioning during subsequent exposures, a positioning component 9 is provided to move the substrate to the designated position. Additionally, a ratchet component 8 is provided to move from the exposure position to the initial position and close the control switch 51 after the substrate exposure is completed.

[0031] The lower rotating shaft 522 is also connected to the positioning component 9 on the support plate 2 and the ratchet component 8 on the detection platform 1. The positioning component 9 includes a turntable 91, a clamping rod 92 and an inner rod 93. The inner rod 93 is fixed on the lower rotating shaft 522. The top end of the inner rod 93 passes through the upper rotating shaft 521 and is connected to a spring. The turntable 91 is sleeved on the inner rod 93 and the two rotate synchronously. The turntable 91 can slide on the inner rod 93. Several arc grooves are opened on the turntable 91. One end of the clamping rod 92 passes through the arc groove. The support panel 4 has a strip groove. The clamping rod 92 passes through the strip groove and is locked in the strip groove. The turntable 91 rotates to drive the clamping rod 92 to move back and forth along the strip groove.

[0032] The top groove of the clamping rod 92 is connected to the chuck 921 by a spring, and the chuck 921 moves to position the substrate.

[0033] The lower rotating shaft 522 and the inner rod 93 rotate synchronously. When the substrate moves from the initial position to the exposure position, the lower rotating shaft 522 drives the turntable 91 to rotate during the rotation. The rotation of the turntable 91 pushes several clamping rods 92 to move simultaneously along the strip groove and the moving distance is the same, thereby pushing the substrate toward the center position to ensure that the substrate moves to the designated position. After the substrate moves to the designated position, the substrate is also flattened.

[0034] The second ratchet assembly 8 includes a rack 81, a ratchet 82, a baffle 83, and a ring 84. The ring 84 is mounted on the rotating lower shaft 522, the rack 81 is set on the detection platform 1, the ratchet 82 is hinged to the ring 84, and the ratchet 82 is also connected to the ring 84 by a spring. The baffle 83 is fixed to the ring 84 to limit the rotation direction of the ratchet 82. When the ratchet 82 moves from the initial position to the exposure position, the upper rotating shaft 521 drives the lower rotating shaft 522 to rotate. The lower rotating shaft 522 opens the valve 5 and the chuck 921 clamps the substrate. When the ratchet 82 moves back from the exposure position to the initial position, the lower rotating shaft 522 rotates in the opposite direction to close the valve 5 and the chuck 921 releases the substrate.

[0035] Since the ratchet 82 can rotate around the ring body 84 in one direction, when the substrate moves from the initial position to the exposure position, the ratchet 82 will pass through the rack 81. At the same time, the ratchet 82 rotates synchronously with the rotating lower shaft 522. During the rotation, the ratchet 82 can rotate around the ring body 84 and compress the spring. After exposure, when the ratchet 82 moves from the exposure position to the initial position, the ratchet 82 contacts the rack 81. At this time, the rack 81 pushes the ratchet 82 to rotate in the opposite direction. Due to the restriction of the baffle 83, the ratchet 82 drives the lower rotating shaft 522 to rotate in the opposite direction. The reverse rotation of the lower rotating shaft 522 pushes the clamping rod 92 to move in the opposite direction. It can also turn off the switch 51, which makes it convenient to remove the substrate later. The clamp 92 releases the base plate and rotates the lower shaft 522 in the direction of rotation. This rotation also pushes the upper tooth 72 to retract into the groove of the upper shaft 521 and compress the spring, thereby achieving the purpose of rotating the upper shaft 521 without rotating it, and keeping the position of the upper shaft 521 unchanged.

[0036] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An exposure device for display screen production, characterized in that, include: The testing platform (1) is equipped with a sliding support plate (2). The testing platform (1) is set with an initial position and an exposure position. The support plate (2) is used to transport the substrate of the display screen back and forth between the initial position and the exposure position. The pressure plate (3) is mounted on the detection platform (1) and located on the moving path between the initial position and the exposure position. The pressure plate (3) can be raised and lowered. The pressure plate (3) contacts the substrate to flatten the substrate warping. The support panel (4) is provided with a number of negative pressure through holes (41), and the number of negative pressure through holes (41) are connected to the main air pipe (42). The main air pipe (42) is connected to the negative pressure pump. The negative pressure through holes (41) are used to adsorb the flattened substrate. The support panel (4) is connected to the support plate (2) through an elastic telescopic rod. A valve (5) is installed inside the main air pipe (42). The valve (5) is rotated to control the opening or closing of the main air pipe (42). A switch (51) that controls the rotation of the valve (5) is connected to a rotating shaft (52). The rotating shaft (52) is mounted on a support panel (4). The pressure plate (3) is raised and lowered, which drives the support panel (4) to rise and fall synchronously. A ratchet (6) provided on the support panel (4) is connected to the rotating shaft (52). During one rise and fall, the rotating shaft (52) is driven. During one rise and fall, the support panel (4) drives the rotating shaft (52) and the switch (51) to rotate synchronously to open the main air pipe (42). During the next rise and fall, the support panel (4) rotates synchronously through the rotating shaft (52) and the switch (51) to close the main air pipe (42). This allows the pressure plate (3) to open the main air pipe (42) during the process of the support plate (2) moving to the exposure position and lowering to flatten the substrate of the display screen. The substrate of the display screen is held in place by negative pressure to keep it flat.

2. The exposure equipment for display screen production according to claim 1, characterized in that, The pressure plate (3) is connected to the cylinder / hydraulic cylinder on the testing platform (1), and the area of ​​the pressure plate (3) is larger than the area above the support panel (4).

3. The exposure equipment for display screen production according to claim 1, characterized in that, The ratchet component (6) includes an upper plate (61), a lower plate (62), an upper ratchet seat (63), and a lower ratchet seat (64). The upper ratchet seat (63) is fixed on the upper plate (61), and the lower ratchet seat (64) is fixed on the lower plate (62). The upper plate (61) and the lower plate (62) are connected to the support rod on the support panel (4). The tooth grooves between the upper ratchet seat (63) and the lower ratchet seat (64) are staggered and form a control channel.

4. The exposure equipment for display screen production according to claim 3, characterized in that, The rotating shaft (52) includes an upper rotating shaft (521) and a lower rotating shaft (522), which are connected by a ratchet assembly (7). The upper rotating shaft (521) passes through the lower plate (62) and the lower ratchet seat (64). The side rod (10) fixed at the top of the upper rotating shaft (521) is located in the control channel.

5. The exposure equipment for display screen production according to claim 4, characterized in that, The ratchet assembly 1 (7) includes a convex ring (71), an upper tooth (72) and a lower tooth (73). The convex ring (71) has a "T" shaped cross section. The convex ring (71) is fixed on the top of the rotating lower shaft (522). The convex ring (71) is inserted into the annular groove of the rotating upper shaft (521) to keep the rotating upper shaft (521) and the rotating lower shaft (522) coaxial. The upper tooth (72) is inserted into the groove at the bottom of the rotating upper shaft (521) by a spring, and the lower tooth (73) is fixed on the top of the rotating lower shaft (522). The upper tooth (72) and the lower tooth (73) are interlocked and arranged in a ring shape.

6. The exposure equipment for display screen production according to claim 4, characterized in that, The rotating lower shaft (522) is also connected to the positioning component (9) on the support plate (2) and the ratchet component two (8) on the detection platform (1).

7. The exposure equipment for display screen production according to claim 6, characterized in that, The positioning component (9) includes a turntable (91), a clamping rod (92), and an inner rod (93). The inner rod (93) is fixed on the lower rotating shaft (522). The top end of the inner rod (93) passes through the upper rotating shaft (521) and is connected to a spring. The turntable (91) is sleeved on the inner rod (93) and the two rotate synchronously. The turntable (91) can slide on the inner rod (93). Several arc grooves are opened on the turntable (91). One end of the clamping rod (92) passes through the arc groove. The support panel (4) has a strip groove. The clamping rod (92) passes through the strip groove and is locked in the strip groove. The turntable (91) rotates to drive the clamping rod (92) to move back and forth along the strip groove.

8. The exposure equipment for display screen production according to claim 7, characterized in that, The top groove of the clamp (92) is connected to the clamp (921) by a spring, and the clamp (921) moves to position the substrate.

9. The exposure equipment for display screen production according to claim 8, characterized in that, The second ratchet assembly (8) includes a rack (81), a ratchet (82), a baffle (83), and a ring (84). The ring (84) is mounted on the rotating lower shaft (522), the rack (81) is set on the detection platform (1), the ratchet (82) is hinged to the ring (84), and the ratchet (82) is also connected to the ring (84) by a spring. The baffle (83) is fixed on the ring (84) to limit the rotation direction of the ratchet (82).

10. An exposure apparatus for display screen production according to claim 9, characterized in that, When the ratchet (82) moves from the initial position to the exposure position, the upper rotating shaft (521) drives the lower rotating shaft (522) to rotate. The lower rotating shaft (522) opens the valve (5) and the chuck (921) clamps the substrate. When the ratchet (82) moves back from the exposure position to the initial position, the lower rotating shaft (522) rotates in the opposite direction to close the valve (5) and the chuck (921) releases the substrate.

Images