CN114326315A

CN114326315A - Light beam transmittance adjusting device and optical lighting system

Info

Publication number: CN114326315A
Application number: CN202011062625.2A
Authority: CN
Inventors: 吴飞; 张洪博
Original assignee: Shanghai Micro Electronics Equipment Co Ltd
Current assignee: Shanghai Micro Electronics Equipment Co Ltd
Priority date: 2020-09-30
Filing date: 2020-09-30
Publication date: 2022-04-12

Abstract

The embodiment of the invention discloses a light beam transmittance adjusting device and an optical lighting system. The light beam transmittance adjusting device comprises a driving unit and at least one group of transmittance adjusting units; the transmittance adjusting unit comprises a grid plate and a rotating shaft, wherein the grid plate comprises a plurality of grids which are formed by a plurality of grid bars in a separating mode and are distributed uniformly; the rotating shaft is parallel to the grid plate and is fixedly connected with one side of the grid plate, the grid plate is arranged on a propagation path of the light beam, and the rotating shaft is arranged on one side of the light beam and is vertical to the propagation direction of the light beam; the driving unit drives the rotating shaft to rotate and drives the grid plate to change an included angle with the propagation direction of the light beam, so that the light-transmitting area of the grid plate along the propagation direction of the light beam changes, and adjustment of different light beam transmittances is achieved. The embodiment of the invention can realize the continuous adjustment of the transmittance in all gears by adopting a mechanical mode, can accurately adjust the power of the light source in the optical illumination system, and avoids the influence of the power difference of the light source of a multi-light source system on the illumination system.

Description

Light beam transmittance adjusting device and optical lighting system

Technical Field

The embodiment of the invention relates to the technical field of photoetching, in particular to a light beam transmittance adjusting device and an optical illumination system.

Background

For a lighting system in the form of a double lamp or a multi-lamp, there is a certain difference (about 2%) in the light power of different light sources under the same power. In the case where there is no transmittance adjusting device, when there is a variation in optical power, it is necessary to adjust the power of the light source so that the optical powers of the respective illumination branches are made uniform. This approach is costly, complex to operate, and time consuming. Therefore, a transmittance adjusting device is usually added to the illumination system to adjust the light emitted from the illumination system, so as to obtain a more uniform illumination condition.

The existing transmittance adjusting device generally adopts an optical compensator or a mechanical blade structure. The optical compensator occupies a large space along the optical axis direction, has a complex structure and is high in cost; the transmittance adjusting device of the mechanical rotary vane type is traditionally of a multi-gear vane structure. The blades of the device are composed of circular holes, and because a light blocking area is arranged between the circular holes, the transmittance range of the device is limited, the illumination of each gear is a fixed value, and generally, the device can only adjust the illumination effects of 25%, 50%, 75% and the like. As can be seen from this, the conventional mechanical rotary vane type transmittance adjustment device has a relatively simple structure, but has a limited transmittance adjustment range, has a fixed transmittance for each gear, cannot achieve continuous transmittance adjustment, and cannot effectively solve the problem of optical power variation of each light source in the illumination system.

Disclosure of Invention

The invention provides a light beam transmittance adjusting device and an optical illumination system, which are used for realizing continuous adjustment of transmittance and ensuring the uniformity of light spots of transmitted light beams.

In a first aspect, an embodiment of the present invention provides a light beam transmittance adjusting apparatus, including a driving unit and at least one group of transmittance adjusting units, where the at least one group of transmittance adjusting units are sequentially arranged along a propagation path of a light beam;

the transmittance adjusting unit comprises a grid plate and a rotating shaft, wherein the grid plate comprises a plurality of grids which are formed by a plurality of grid bars in a separated mode and are distributed uniformly;

the rotating shaft is parallel to the grid plate and fixedly connected with one side of the grid plate, the grid plate is arranged on a propagation path of the light beam, and the rotating shaft is arranged on one side of the light beam and is vertical to the propagation direction of the light beam;

the driving unit drives the rotating shaft to rotate and drives the grid plate to change an included angle between the grid plate and the propagation direction of the light beam, so that the light transmission area of the grid plate along the propagation direction of the light beam changes.

Optionally, the beam transmittance adjusting device comprises a set of the transmittance adjusting units; in the grid plate in the transmittance adjusting unit, the grid bars are arranged in a crossed manner and separated to form the grids which are uniformly distributed.

Optionally, the beam transmittance adjusting device comprises a first transmittance adjusting unit and a second transmittance adjusting unit; the first transmittance adjusting unit comprises a first grid plate and a first rotating shaft, and the first rotating shaft is parallel to the first grid plate and is fixedly connected with one side of the first grid plate; the second transmittance adjusting unit comprises a second grid plate and a second rotating shaft, and the second rotating shaft is parallel to the second grid plate and is fixedly connected with one side of the second grid plate;

the grid bars in the first grid plate and the second grid plate are respectively arranged in parallel and separated to form the grids which are uniformly distributed, and the grid bars in the first grid plate and the grid bars in the second grid plate are mutually vertical; the first rotating shaft is parallel to the grid bars in the first grid plate, and the second rotating shaft is parallel to the grid bars in the second grid plate;

under the driving of the driving unit, the first grid plate and the second grid plate respectively have the same included angle with the propagation direction of the light beam.

Optionally, the first transmittance adjustment unit further comprises a first gear, and the second transmittance adjustment unit further comprises a second gear; the first gear and the second gear are mutually meshed staggered shaft helical gears, and a rotating shaft of the first gear is vertical to a rotating shaft of the second gear;

the first gear is coaxially and fixedly connected with the first rotating shaft, the second gear is coaxially and fixedly connected with the second rotating shaft, and one end of the first rotating shaft is in transmission connection with the driving unit;

the driving unit drives the first rotating shaft to rotate and drives the first gear, the second gear and the second rotating shaft to rotate, so that an included angle between the first grid plate and the second grid plate and a propagation direction of a light beam is changed, and a light transmission area of the first grid plate and the second grid plate along the propagation direction of the light beam is changed.

Optionally, the width of the grid bars ranges from 10nm to 1mm, the width of the grid ranges from 10nm to 5mm, the thickness of the first grid plate and the second grid plate ranges from 10nm to 5mm, the total number of the grids ranges from 10 to 100000, the ratio of the width of the grid bars to the width of the grid ranges from 0.01 to 1, and the ratio of the width of the grid bars to the thickness of the grid plates ranges from 0.01 to 1.

Optionally, the width of the grid bars ranges from 10nm to 1mm, the width of the grids ranges from 10nm to 5mm, the thickness of the grid plates ranges from 10nm to 5mm, the total number of the grids ranges from 10 to 100000, the ratio of the width of the grid bars to the width of the grids ranges from 0.001 to 1000, and the ratio of the width of the grid bars to the thickness of the grid plates ranges from 0.001 to 1000.

Optionally, the grid pattern in the grid plate is any one of a polygon, a circle, an ellipse and a fan.

Optionally, the grid plate is a square plate, and the rotation axis is perpendicular to a diagonal line of the grid plate.

Optionally, when an included angle between the grid plate and the propagation direction of the light beam is 90 °, the transmittance of the grid plate is 80%; when the included angle between the grid plate and the propagation direction of the light beam is 45 degrees, the transmittance of the grid plate is 20 percent.

Optionally, the drive unit comprises a motor, a coupling and a decoder;

the motor is in transmission connection with the rotating shaft through the coupler and is used for driving the rotating shaft to rotate; the decoder is sleeved on the rotating shaft in a sleeving manner and used for acquiring the rotating angle of the rotating shaft.

Optionally, the transmittance adjustment unit further comprises a frame, the grid plate being disposed in the frame;

one side of the frame is fixedly connected with the rotating shaft, and the frame rotates along with the rotating shaft.

Optionally, the light beam transmittance adjusting device further includes an outer frame, and two opposite sides of the outer frame are respectively provided with a light through hole for passing light beams;

the at least one group of transmittance adjusting units are arranged inside the outer frame.

Optionally, the light beam transmittance adjusting device further includes a heat dissipation unit, and the heat dissipation unit is disposed on an outer wall of the outer frame.

Optionally, the grid plate comprises a substrate and a grid layer arranged on one side surface of the substrate, the grid layer comprises a plurality of grids, and the grids are separated to form a plurality of grids which are uniformly distributed;

or the grid plate comprises a first grid layer and a second grid layer which are stacked, and the first grid layer and the second grid layer are respectively provided with a plurality of grid strips; the grid bars in the first grid bar layer and the second grid bar layer are vertically projected and separated on the plane where the first grid bar layer is located to form a plurality of grid bars which are uniformly distributed.

Optionally, the grid plate is prepared and formed by a 3D printing process or a photolithography process.

In a second aspect, an embodiment of the present invention further provides an optical illumination system, including the light beam transmittance adjusting apparatus according to any one of the first aspects, further including a light source system, an illumination system, and a projection objective;

the light beam transmittance adjusting device, the illumination system and the projection objective are sequentially arranged on a light path of a light beam emitted by the light source system.

The light beam transmittance adjusting device and the optical lighting system provided by the embodiment of the invention utilize a driving unit and at least one group of transmittance adjusting units in the adjusting device, wherein the transmittance adjusting units comprise grids and a rotating shaft, the grid plate comprises a plurality of grids which are formed by a plurality of grid bars in a separating mode and are uniformly distributed, the rotating shaft is parallel to the grid plate and is fixedly connected with one side of the grid plate, the grid plate is arranged on a propagation path of a light beam, the rotating shaft is arranged on one side of the light beam and is vertical to the propagation direction of the light beam, and the driving unit drives the rotating shaft to rotate, so that an included angle between the grid plate and the propagation direction of the light beam can be driven to change, the light transmission area of the grid plate along the propagation direction of the light beam can be changed, and the adjustment of different light beam transmittances can be realized. The embodiment of the invention can realize the continuous adjustment of the transmittance in all gears by adopting a mechanical mode, can accurately adjust the power of the light source in the optical illumination system, and avoids the influence of the power difference of the light source of a multi-light source system on the illumination system. Compared with the existing circular hole type transmittance adjusting mode, the embodiment of the invention can ensure that the relative deviation of two equidistant points of the pupil transmittance is consistent, the maximum deviation is minimum, and the three technical indexes of static uniformity within 2%, integral uniformity within 1.5% and pupil uniformity within 5% can be ensured by integrating all exposure gears. In addition, the light beam transmittance adjusting device that this embodiment provided can guarantee that the transmittance is along with the change of rotation angle and stable variation, also can guarantee that the transmittance variation trend is stable when also can guaranteeing transmittance continuous adjustment, conveniently adjusts the transmittance according to the rotation angle accuracy.

Drawings

FIG. 1 is a schematic structural diagram of a conventional beam transmittance adjusting apparatus;

fig. 2 is a schematic structural diagram of a light beam transmittance adjusting device according to an embodiment of the present invention;

FIG. 3 is a top view of the beam transmittance adjusting apparatus shown in FIG. 2;

FIG. 4 is a schematic structural diagram of a grid plate in the beam transmittance adjusting apparatus shown in FIG. 2;

FIG. 5 is a schematic diagram of the beam transmittance adjustment apparatus of FIG. 2;

FIG. 6 is a schematic view of a grid plate provided by an embodiment of the present invention;

FIG. 7 is a schematic structural diagram of another device for adjusting the transmittance of a light beam according to an embodiment of the present invention;

FIG. 8 is a top view of the beam transmittance adjusting apparatus shown in FIG. 7;

FIGS. 9 and 10 are schematic structural views of two more types of grid plates provided by embodiments of the present invention;

FIG. 11 is a schematic view of a grid plate preload installation provided by an embodiment of the invention;

FIG. 12 is a pupil illumination pattern of the beam transmittance adjustment apparatus shown in FIG. 7 with spot variation with rotation angle;

FIG. 13 is a graph of transmittance versus rotation angle for the beam transmittance adjustment apparatus of FIG. 7;

FIG. 14 is a graph of the derivative of the transmittance of the beam transmittance adjustment apparatus of FIG. 7 versus the angle of rotation;

FIG. 15 is a graph of transmittance versus rotation angle for the beam transmittance adjustment apparatus of FIG. 7;

FIG. 16 is an illumination uniformity evaluation of the beam transmittance adjusting apparatus of FIG. 7;

FIG. 17 is a schematic structural diagram of another device for adjusting the transmittance of a light beam according to an embodiment of the present invention;

FIG. 18 is a side view of the beam transmittance adjusting apparatus shown in FIG. 17;

FIG. 19 is a schematic perspective view of the optical path of the light beam transmittance adjusting apparatus shown in FIG. 17;

fig. 20 is a schematic view of a gear structure in the beam transmittance adjusting apparatus shown in fig. 17;

FIG. 21 is a pupil illumination pattern of the beam transmittance adjustment apparatus shown in FIG. 17 with spot variation with rotation angle;

FIG. 22 is a graph of transmittance versus rotation angle for the beam transmittance adjustment apparatus of FIG. 17;

FIG. 23 is a graph of the derivative of the transmittance of the beam transmittance adjustment device of FIG. 17 versus the angle of rotation;

FIG. 24 is a graph of transmittance versus rotation angle and error for the beam transmittance adjustment apparatus of FIG. 17;

FIG. 25 is an illumination uniformity evaluation of the beam transmittance adjusting apparatus of FIG. 17;

FIGS. 26 and 27 are schematic structural views of a first grid plate and a second grid plate of the beam conditioning device of FIG. 17;

fig. 28 and 29 are schematic structural diagrams of two optical illumination systems provided by the embodiment of the invention.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.

As described in the background section, fig. 1 is a schematic structural diagram of a conventional light beam transmittance adjusting apparatus, and referring to fig. 1, in the conventional light beam transmittance adjusting apparatus, a light beam transmittance adjusting structure mainly includes a rotating blade 10, a plurality of circular light transmitting areas 100 are disposed on the rotating blade 10, and each circular light transmitting area 100 includes light transmitting holes which are uniformly distributed and have different densities, and it is obvious that when the rotating blade 10 rotates to one of the gears, that is, when a certain circular light transmitting area 100 rotates to a light beam path, the arrangement density of the light transmitting holes in the circular light transmitting area 100 determines the transmittance of the light beam. By appropriately setting the arrangement density of the light transmission holes, the rotary blade 10 can be set to a plurality of transmittance steps, for example, 25%, 50%, 75%, and 100%. Obviously, the light beam transmittance adjusting device composed of the rotating blades cannot realize other transmittances except for gear setting, and cannot realize continuous adjustment of the transmittance, for example, cannot realize any transmittance within the range of 20% -100%.

Based on this, the embodiment of the invention provides a light beam transmittance adjusting device. Fig. 2 is a schematic structural diagram of a light beam transmittance adjusting apparatus according to an embodiment of the present invention, fig. 3 is a top view of the light beam transmittance adjusting apparatus shown in fig. 2, fig. 4 is a schematic structural diagram of a grid plate in the light beam transmittance adjusting apparatus shown in fig. 2, fig. 5 is a schematic diagram of light beam transmittance adjustment of the light beam transmittance adjusting apparatus shown in fig. 2, referring to fig. 2-5, the light beam transmittance adjusting apparatus includes a driving unit 30 and at least one set of transmittance adjusting units 20, and the at least one set of transmittance adjusting units 20 are sequentially arranged along a propagation path of a light beam; the transmittance adjusting unit 20 includes a grid plate 21 and a rotating shaft 22, the grid plate 21 includes a plurality of grids 212 which are formed by a plurality of grid bars 211 and are uniformly distributed; the rotating shaft 22 is parallel to the grid plate 21 and is fixedly connected with one side of the grid plate 21, the grid plate 21 is arranged on a propagation path of the light beam, and the rotating shaft 22 is arranged on one side of the light beam and is vertical to the propagation direction of the light beam;

the driving unit 30 drives the rotating shaft 22 to rotate, and drives the grid plate 21 to change an included angle with the propagation direction of the light beam, so that the light transmission area of the grid plate 21 along the propagation direction of the light beam changes.

Referring to fig. 4 a) and b), the grid plate 21 has a grid 212 formed by dividing the grid bars 211, which is substantially a three-dimensional structure, rather than a two-dimensional pattern, and the grid bars 211 have not only a certain length and width, but also a certain height or thickness. The grid bars 211 are arranged at equal intervals, and the grid bars 212 partitioned by the grid bars are light-transmitting grid bars, part of the light beams can pass through the light-transmitting grid bars 212, and part of the light beams can be shielded by the grid bars 211 to change the propagation direction. The resulting spot pattern formed by the projection of the light beam through the grid plate 21 will be the pattern formed by the grid bars 211 in the grid plate 21. The light-shielding and transmission process of the grid plate and the adjustment principle of the light beam transmittance are described below.

As shown in fig. 5, a parallel or quasi-parallel light beam is provided to irradiate the grating plate 21 from the bottom, and when the grating plate 21 is placed in a horizontal position, i.e. perpendicular to the light beam, the light path is transmitted through the grating as shown in a) of fig. 5. When the single grid is analyzed, part of light irradiates on an OA surface (namely, the grid bars 211) and is reflected by the OA surface, and the reflection follows the reflection law, so that the light deviates from the original light path direction. Part of the light irradiates the AB line segment, is not blocked by any shielding and continues to propagate upwards, so that the part of the light beam is transmitted.

Referring to b) of fig. 5, assuming that a parallel or quasi-parallel light beam irradiates the grid plate 21 from the bottom, the grid plate 21 is rotated at a certain angle around the rotation axis 22, and the grid plate 21 is in a tilted state. When the single grid 212 is analyzed, part of light is irradiated on the OA surface (namely, the grid bars 211) and reflected by the OA surface, and the reflection follows the reflection law, so that the light is deviated from the original light path direction. Part of light irradiates in the projection range of the AC line segment in the X direction, is not blocked by any shielding and continues to propagate upwards, so that the part of light beam is transmitted. Part of the light irradiates on the BC surface (the inner wall of the grating strip 211) and is reflected by the BC surface, and the reflection follows the reflection law, so that the light deviates from the original light path direction. Part of the light is irradiated on the BD surface (i.e. the grating bars 211) of the next grating and is reflected by the BD surface, and the reflection follows the reflection law, so that the light deviates from the original light path direction. The grating strips 211 can be made of a good reflective material, and all light or radiation impinging on the end faces and inner walls of the grating plate is reflected (specular or diffuse) or absorbed.

Note that, as the rotation angle θ changes from 0 degrees to 90 degrees, the end surface reflection initially occupies the main reflection surface, and the inner wall reflection occupies the main reflection surface when the rotation angle θ becomes larger. Furthermore, from geometric reasoning, the number of grids coming into the beam range is also increasing. The transmittance adjustment pattern of the present invention is actually an effect of superimposing the patterns of the grids in the grid plate 21. The light spot transmittance forms the effect of adjustable continuous gradual change transmittance along with the change of the rotation angle.

It can be seen that, when the grating bars 211 of the grating plate 21 block the light beam, the grating 212 transmits the light beam, and when the rotation angle of the grating plate 21 is increased, the blocking of the light beam by the grating bars 211 is increased, and the light transmission area of the light transmission area, i.e., the grating 212 in the light beam propagation direction is decreased, thereby decreasing the transmittance of the light beam. As shown in fig. 2-5, there is provided a three-dimensional cartesian coordinate system according to the left-hand rule, which includes mutually perpendicular X, Y and Z axes, and the grid plate 21 is rotatable about the X axis in the coordinate system shown in the drawing, within the range of 0 ° to 90 °. The grating plate 21 is at its initial position when it is placed in a horizontal position, i.e., the XZ plane, at a rotation angle of 0 °, where the transmittance of the light beam is in the range of about 80% -90%. When the rotation angle of the grid plate 21 is 45 °, the transmittance of the light beam is in the range of about 10% -20%. The effective continuous adjustment range is within the range of 0-45 degrees of the rotation angle. When the rotation angle of the grid plate 21 is 90 °, the two-dimensional transmission grid 101 will output the range of the light beam, and the transmittance of the light beam is 100%.

It should be noted that the transmittance adjusting device is a part of the optical illumination system, and the transmittance adjustment is realized while the original static uniformity, integral uniformity and pupil uniformity of the optical illumination system are maintained. The static uniformity refers to uniform change of transmittance through rotation angle, the integral uniformity refers to uniform change of multiple rate of increase or decrease of transmittance through rotation angle, and the pupil uniformity refers to symmetric distribution of transmitted light illumination area. For an illumination system using a mercury lamp as a light source, the energy is gaussian before the dodging unit, and the illumination system should have good symmetry and uniformity. Based on this, in the embodiment of the present invention, the grids 212 on the grid plate 21 should be arranged to be uniformly distributed, and in this case, the light beam can be uniformly filtered as much as possible when passing through the grid plate 21, that is, the light beam can be uniformly filtered. In addition, the transmittance adjusting units 20 may be arranged in one group, but on one hand, the transmittance adjusting units 20 may adjust the transmittance of the light beams respectively, so as to adjust the transmittance more finely after the light beams are overlapped, thereby increasing the adjustment precision of the transmittance; on the other hand, the plurality of sets of transmittance adjusting units 20 can cooperate with each other to sequentially compensate and optimize the uniformity of the transmitted light beam, so that the finally transmitted light beam has good uniformity, and the influence of the distribution of the grids 212 in the grid plate 21 on the uniformity of the light beam is reduced.

The light beam transmittance adjusting device provided by the embodiment of the invention utilizes a driving unit and at least one group of transmittance adjusting units, wherein each transmittance adjusting unit comprises a grid and a rotating shaft, a grid plate comprises a plurality of grids which are uniformly distributed and separated by a plurality of grid bars, the rotating shaft is parallel to the grid plate and is fixedly connected with one side of the grid plate, the grid plate is arranged on a propagation path of a light beam, the rotating shaft is arranged on one side of the light beam and is vertical to the propagation direction of the light beam, and the driving unit drives the rotating shaft to rotate, so that the included angle between the grid plate and the propagation direction of the light beam can be driven to change, the light transmission area of the grid plate along the propagation direction of the light beam can be changed, and the adjustment of different light beam transmittances can be realized. The embodiment of the invention can realize the continuous adjustment of the transmittance in all gears by adopting a mechanical mode, can accurately adjust the power of the light source in the optical illumination system, and avoids the influence of the power difference of the light source of a multi-light source system on the illumination system. Compared with the existing circular hole type transmittance adjusting mode, the embodiment of the invention can ensure that the relative deviation of two equidistant points of the pupil transmittance is consistent, the maximum deviation is minimum, and the three technical indexes of static uniformity within 2%, integral uniformity within 1.5% and pupil uniformity within 5% can be ensured by integrating all exposure gears. In addition, the light beam transmittance adjusting device that this embodiment provided can guarantee that the transmittance is along with the change of rotation angle and stable variation, also can guarantee that the transmittance variation trend is stable when also can guaranteeing transmittance continuous adjustment, conveniently adjusts the transmittance according to the rotation angle accuracy.

In the above-mentioned light beam transmittance adjusting device, the driving unit 30 is responsible for driving the rotating shaft 22 to rotate, and drives the grid plate 21 to rotate around the rotating shaft 22. Therefore, with continued reference to fig. 2, in order to achieve driving of the rotating shaft 22, a drive unit 30 may be provided, illustratively, comprising a motor 31, a coupling 32 and a decoder 33; the motor 31 is in transmission connection with the rotating shaft 22 through a coupler 32 and is used for driving the rotating shaft 22 to rotate; the decoder 33 is looped around the rotating shaft 22 for acquiring the rotation angle of the rotating shaft 22. The motor 31 and the coupling 32 are responsible for providing rotation power to the rotating shaft 22 to drive the rotating shaft 22 to rotate, and the decoder 33 can feed back and control the rotation angle of the rotating shaft 22 to precisely adjust the rotation angle of the rotating shaft 22. After the relationship between the rotation angle and the light beam transmittance of the transmittance adjustment unit 20 is known, the light beam transmittance of the transmittance adjustment unit 20 can be precisely adjusted by the driving unit 30.

Furthermore, the grid plate can be directly and fixedly connected with the rotating shaft, namely the grid plate has certain rigidity, and the rotating shaft directly drives the grid plate to rotate. Considering that the grid plate itself acts as the adjustment of the light beam transmittance, wherein the grids and the bars need to be designed with a certain density, in order to avoid the deformation of the grids and the bars during rotation and influence the transmittance, with continuing reference to fig. 2, optionally, the transmittance adjustment unit 20 may further include a frame 23, and the grid plate 21 is disposed in the frame 23; one side of the frame 23 is fixedly connected to the rotating shaft 22, and the frame 23 rotates along with the rotating shaft 22. In this case, the grid plate 21 itself can be protected and supported by the frame 23, and damage can be prevented from occurring during rotation, and deformation of the grid plate 21 can be prevented, thereby preventing an error in adjustment of the light beam transmittance.

Further optionally, the light beam transmittance adjusting device may further include an outer frame 40, and two opposite sides of the outer frame 40 are respectively provided with a light-passing hole for passing light beams; at least one set of transmittance adjustment units 20 is disposed inside the outer frame 40. The outer frame 40 is mainly used for protecting and supporting the whole light beam transmittance adjusting device, and can also prevent excessive deposition of dust in the air and the like from affecting the uniformity of the light beam. On this basis, it is considered that the transmittance adjustment unit 20 in the outer frame 40 needs to block the transmission of a part of the light beam while adjusting the transmittance of the light beam, and therefore the transmittance adjustment unit 20, particularly the grid plate 21, absorbs the heat of the illumination, thereby causing the temperature inside the outer frame 40 to increase. Therefore, the light beam transmittance adjusting apparatus may include a heat dissipating unit 50, and the heat dissipating unit 50 is disposed on an outer wall of the outer frame 40. The heat dissipation unit 50 may specifically include a heat dissipation sheet and a heat dissipation system (not shown in the figure), the heat dissipation sheet may be attached to an outer wall of the outer frame to absorb heat of the outer frame, and then the heat dissipation is performed through the heat dissipation system, so as to achieve cyclic heat dissipation, ensure that the temperature of the light beam transmittance adjustment device is normal in the working state, and avoid the deformation of the grid plate due to the high temperature and influence on the adjustment precision of the light beam transmittance.

On the basis of the beam transmittance adjusting device, the embodiment of the invention further researches and designs the structure of the grating plate in the transmittance adjusting unit. In the beam transmittance adjusting apparatus shown in fig. 2 to 5, optionally, the beam transmittance adjusting apparatus includes a set of transmittance adjusting units 20; in the grid plate 21 of the transmittance adjusting unit 20, the grid bars 211 are arranged in a crossed manner to form uniformly arranged grids 212. Specifically, the pattern of the grids 212 in the grid plate 21 may be provided in any one of a polygon, a circle, an ellipse, and a fan shape. Fig. 6 is a schematic diagram of a grid plate according to an embodiment of the present invention, and referring to fig. 6, taking a polygon as an example, the grid 212 in the grid plate 21 may be a square, a rectangle, a triangle, a hexagon, and the like, and a person skilled in the art may design the shape and arrangement of the grid according to an actual transmittance requirement, which is not limited herein.

Fig. 7 is a schematic structural diagram of another beam transmittance adjusting apparatus according to an embodiment of the present invention, and fig. 8 is a top view of the beam transmittance adjusting apparatus shown in fig. 7, referring to fig. 7 and 8, in the beam transmittance adjusting apparatus, a grid plate 21 is a square plate, and a rotation axis 22 is perpendicular to a diagonal line of the grid plate 21.

Similarly, referring to fig. 4, the grid plate 21 is provided with grid bars 211 at equal intervals, the grid bars 211 are alternately separated to form transparent grids 212, and when the light beam passes through the grids 212, part of the light beam is shielded by the grid bars 211. Therefore, the final spot pattern formed by the projection of the light beam through the grid plate 21 will be the pattern of the grid plate 21. The grating bars 211 and the gratings 212 in the grating plate 21 constitute a partially light-shielding region and a light-transmitting region. The grid plate 21 is divided by the criss-cross grid bars 211 to form a geometric pattern of an array distribution, and correspondingly, the transmission area and the light shielding area are also distributed in a geometric pattern array. The transparent region is a transparent region of the grid 212 in the beam propagation direction, and the area thereof determines the beam transmittance of the grid plate 21.

As shown in fig. 7 and 8, a three-dimensional cartesian coordinate system complying with the left-hand rule is provided. The grid plate 21 and the frame 23 are rotatable about axes of 45 degrees of the XZ plane in the illustrated coordinate system, in the range of 0 ° to 90 °. The grating plate 21 and the frame 23 are at their initial positions when they are placed in the horizontal position, i.e., the XZ plane, at a rotation angle of 0 °, at which the transmittance of the light beam is in the range of about 80% to 90%. When the rotation angle of the grid plate 21 and the frame 23 is 45 °, the transmittance of the light beam is in the range of about 10% -20%. The effective continuous adjustment range is within the range of 0-45 degrees of the rotation angle. When the rotation angle of the grid plate 21 and the frame 23 is 90 °, the grid plate 21 will turn out the range of the light beam, and the transmittance of the light beam at this time is 100%.

In contrast, in the grid plate 21 shown in fig. 2, since a part of the grid bars 211 is perpendicular to the rotating shaft 22, when the grid plate rotates around the rotating shaft 22, the part of the grid bars 211 cannot increase the shielding of the light beam, and when the grid plate 211 parallel to the rotating shaft 22 rotates around the rotating shaft 22, the shielding of the light beam is increased, so that the light beam passes through the grid plate 21, although the transmittance can be adjusted, the energy difference between the light beam in the two directions parallel to and perpendicular to the rotating shaft 22 is changed, that is, the energy is not uniform in the two directions. In the grid plate 21 shown in fig. 7 and 8, the grid bars and the rotating shaft 22 form an included angle of 45 °, and when the grid plate 21 rotates, the shielding of the light beams by the grid bars can be increased, so that the energy of the light beams in two directions parallel to and perpendicular to the rotating shaft 22 can be relatively more uniform when the light beams penetrate through the grid plate, and the uniformity of the light beams can be ensured.

In order to further ensure that the light beam can still maintain better uniformity after penetrating through the grid plate, the embodiment of the invention performs careful calculation and simulation verification on the specific structure and size of the grid plate in the light beam transmittance adjusting device shown in fig. 2 and 7. Referring to fig. 4, in the grid plate, the width w of the grid bars may be set to range from 10nm to 1mm, the width v of the grid bars may range from 10nm to 5mm, the thickness t of the grid plate may range from 10nm to 5mm, the total number of the grid bars may range from 10 to 100000, the ratio of the width w of the grid bars to the width v of the grid bars may range from 0.001 to 1000, and the ratio of the width w of the grid bars to the thickness t of the grid plate may range from 0.001 to 1000.

Through the width of the grid bars, the width and the width proportion of the grid bars and the range of the width proportion of the grid bars and the thickness proportion of the grid plate, in the tilting process of the grid plate from the vertical light beam to the parallel light beam, the penetration area of the grid in the light beam propagation direction can be ensured to be slowly changed in a reasonable range, the penetration area can not be rapidly reduced, the light beam transmittance can be ensured to be slowly changed, and the accurate target light beam transmittance can be conveniently obtained according to the adjustment of the inclination angle.

In addition, in order to enable the adjustment range of the light beam transmittance of the grid plate to meet the actual requirement, further optionally, when the included angle between the grid plate 21 and the propagation direction of the light beam is 90 degrees, the transmittance of the grid plate is 80%; the transmittance of the grid plate was 20% when the grid plate was at 45 ° to the propagation direction of the beam. The transmittance of the grid plate 21 at a specific angle is set to meet the actual transmittance requirement, and at the same time, the transmittance is also limited by the area of the grid pattern in the grid plate 21 and the structural dimensions such as the thickness of the grid bars in the grid plate 21, obviously, the ratio of the transmittance area of the grid in the light beam propagation direction to the cross-sectional area of the light beam is the transmittance of the light beam, and the transmittance of the grid plate 21 in two states of perpendicular to the light beam and forming an included angle of 45 degrees with the light beam can be ensured by reasonably setting the structural dimensions such as the grid pattern and the thickness of the grid bars.

The embodiment of the invention also carefully studies the specific composition structure and the preparation process of the grid plate. Fig. 9 and 10 are schematic structural diagrams of two types of grid plates provided by an embodiment of the present invention, and alternatively, the grid plate 21 may include a substrate 200 and a grid layer 210 disposed on a side surface of the substrate, the grid layer 100 includes a plurality of grids 211, and the plurality of grids 211 are separated to form a plurality of grids 212 uniformly distributed. Alternatively, the grid plate 21 may also include a first grid layer 2101 and a second grid layer 2102 arranged in a stacked manner, and the first grid layer 2101 and the second grid layer 2102 are respectively provided with a plurality of grids 211; the grills 211 in the first grill layer 2101 and the second grill layer 2102 are separated by a vertical projection on the plane of the first grill layer 2101 to form a plurality of uniformly distributed grills 212.

Fig. 11 is a schematic view of the installation of a grid plate preload according to an embodiment of the present invention, and referring to fig. 11, specifically, when installing the grid plate, in order to improve the uniformity of the wire grid, it is necessary to provide a preload or tension F along the direction of the grid bars to the grid plate 21 in advance, and the preload or tension F is distributed on the whole plane of the grid plate. The grid plate 21 is placed on top and the mounting plate 133 is placed below. As shown in b) of fig. 11, the left side of the grid plate 21 has an end surface directly contacting the end surface of the mounting plate 133. An elastic body 130 is arranged between the right end face and the end face of the mounting plate 133, the elastic body is in a strip shape, and the elastic body 130 can be an elastic reed, rubber or flexible structure device. The elastic body 130 is deformed by being pressed by the right end surface of the grid plate 21 and the end surface of the mounting plate 133, and its reaction force provides a preload force in the direction of the grid bars to the grid plate 21. The grid plate 21 placed on top and the mounting plate 133 placed below are then fastened by means of vertical bolts 132.

For a specific manufacturing process of the grid plate, the grid plate may alternatively be prepared using a 3D printing process or a photolithography process. Taking 3D printing process as an example, in the beam transmittance adjusting device, the grid plate may be made of metal material such as aluminum, stainless steel, etc. or material with good reflective performance. The substrate is manufactured by a 3D printing process, and the thickness of the substrate wall during 3D printing is about 0.1-10 mm. The process flow specifically comprises the following main steps: 3D printing and forming, linear cutting and slicing, sand blasting, ultrasonic cleaning, and plating a film or metal on the surface of the outer layer. The 3D printing process can be used for conveniently printing grid bars with complex patterns, and the manufacturing difficulty and the manufacturing cost of the grid plate are greatly reduced. For the photoetching process, the grid plate can also adopt a method for manufacturing a transmission grid by etching, the grid plate is manufactured by etching or exposing on a substrate with high transmittance such as glass or quartz by adopting an electron beam or a plasma beam, and the wall thickness of the substrate such as the glass or the quartz is about 0.1-10 mm. The grid plate is manufactured by the photoetching process, the manufacturing process is relatively mature, and the grid pattern with more accurate size can be ensured, so that the adjustment of the light beam transmittance is more accurate.

The embodiment of the invention also carries out the experimental study and verification of the light beam transmittance adjusting device shown in fig. 7 and fig. 8, wherein fig. 12 is a pupil illumination pattern of a light spot of the light beam transmittance adjusting device shown in fig. 7 along with the change of a rotation angle, fig. 13 is a relationship curve of transmittance and a rotation angle of the light beam transmittance adjusting device shown in fig. 7, fig. 14 is a relationship curve of transmittance derivative and a rotation angle of the light beam transmittance adjusting device shown in fig. 7, fig. 15 is a relationship curve and an error of transmittance and a rotation angle of the light beam transmittance adjusting device shown in fig. 7, and fig. 16 is the illumination uniformity evaluation of the light beam transmittance adjusting device shown in fig. 7. The rotation angle θ is an angle of the grid plate rotating in the clockwise direction of the rotation shaft with the vertical beam as a starting point.

To further illustrate the optical effect and pattern of the grating plate in blocking the light beam, fig. 12 lists a series of spot patterns as a function of the rotation angle θ, where each sub-image represents a spot pattern rotated by π/64. It is obvious that as the rotation angle θ is gradually increased, the pattern area of the grid in the spot pattern becomes smaller, and the transmittance of the grid plate is decreased. Fig. 13 shows transmittance versus rotation angle as a function of rotation angle, where the transmittance segment corresponds to a rotation angle theta of 0-45 deg., and the beam transmission grating plate forms a patterning effect. Within the angle range of 0-45 degrees, the corresponding transmittance is respectively 80-20 percent, and the effect of continuously and linearly adjusting the transmittance is formed. As shown in fig. 14, the transmittance of the transmittance adjusting means as a function of the rotation angle is further simulated and described, wherein the grid plate forms a pattern effect in the transmittance section corresponding to the rotation angle θ of 0 to 45 °. Within the angle range of 0-45 degrees, the corresponding transmittance is respectively 80-20 percent, and the effect of continuously and linearly adjusting the transmittance is formed. Fig. 14 b) is a graph of transmittance derivative versus rotation angle to verify monotonicity of the continuously adjustable device, where f (x) is a continuous monotonically decreasing function, and the transmittance derivative is smaller than zero in all regions, which indicates that the transmittance is stably reduced when the grid plate rotates with the angle, and the grid plate is in an excellent adjustable range and performance. As shown in fig. 15, when the transmittance section corresponds to the rotation angle of 0 to 45 °, the error between the error of the transmittance and the theoretical linearity value is less than +/-2%, which means that the decrease of the transmittance is stable and linear when the rotation angle θ of the grid plate is increased in the beam transmittance adjusting apparatus. As shown in fig. 16, when the rotation angle of the grid plate is 0-45 °, the energy ratio curves of the light spot formed by the light beam passing through the grid plate in different areas provide an evaluation means for the uniformity of the light beam, and as can be seen from the energy ratio curves in different areas, the evaluation functions of the four quadrants of the light spot are all lower than 4%, and the optical uniformity is in a better performance range.

On the basis of the light beam transmittance adjusting device provided by the above embodiment, the embodiment of the invention also provides a light beam transmittance adjusting device with respect to the number of transmittance adjusting units arranged therein. Fig. 17 is a schematic structural diagram of another light beam transmittance adjusting apparatus provided in an embodiment of the present invention, fig. 18 is a side view of the light beam transmittance adjusting apparatus shown in fig. 17, fig. 19 is a schematic perspective optical path diagram of the light beam transmittance adjusting apparatus shown in fig. 17, and with reference to fig. 17-19, the light beam transmittance adjusting apparatus may include a first transmittance adjusting unit 601 and a second transmittance adjusting unit 602; the first transmittance adjustment unit 601 includes a first grid plate 6101 and a first rotation axis 6201, the first rotation axis 6201 is parallel to the first grid plate 6101 and is fixedly connected to one side of the first grid plate 6101; the second transmittance adjusting unit 602 includes a second grid plate 6102 and a second rotating shaft 6202, the second rotating shaft 6202 is parallel to the second grid plate 6102 and is fixedly connected to one side of the second grid plate 6102;

the grid bars in the first grid plate 6101 and the second grid plate 6102 are respectively arranged in parallel and separated to form a grid which is uniformly arranged, and the grid bars in the first grid plate 6101 are perpendicular to the grid bars in the second grid plate 6102; the first rotation axis 6201 is parallel to the bars in the first grid plate 6101, and the second rotation axis 6202 is parallel to the bars in the second grid plate 6102; under the driving of the driving unit 30, the first grid plate 6101 and the second grid plate 6102 respectively have the same angle with the propagation direction of the light beam.

Fig. 20 is a schematic view of a gear structure in the light beam transmittance adjusting apparatus shown in fig. 17, and referring to fig. 17 to fig. 20, further, the first transmittance adjusting unit 601 further includes a first gear 6301, and the second transmittance adjusting unit 602 further includes a second gear 6302; the first gear 6301 and the second gear 6302 are staggered shaft helical gears which are meshed with each other, and a rotating shaft of the first gear 6301 is perpendicular to a rotating shaft of the second gear 6302; the first gear 6301 is coaxially and fixedly connected with the first rotating shaft 6201, the second gear 6302 is coaxially and fixedly connected with the second rotating shaft 6202, and one end of the first rotating shaft 6201 is in transmission connection with the driving unit 30;

the driving unit 30 drives the first rotating shaft 6201 to rotate, and drives the first gear 6301, the second gear 6302 and the second rotating shaft 6202 to rotate, so as to change an included angle between the first grid plate 6101 and the second grid plate 6102 and the light beam propagation direction, and change a light transmission area of the first grid plate 6101 and the second grid plate 6102 along the light beam propagation direction.

The driving unit 30 may still include a motor 31, a coupling 32, and a decoder 33, the first gear 6301 is a driving gear, and is meshed with the second gear 6302, and the motor 31 may transmit torque to the first gear 6301 and the second gear 602 through the coupling 32. The first gear 6301 and the second gear 6302 are located at the positions of staggered and orthogonal, wherein the first gear 6301 drives the first grid plate 6101 to coaxially rotate synchronously, and the second gear 6302 drives the second grid plate 6102 to coaxially rotate synchronously, so as to realize the synchronous orthogonal axis rotation of the first grid plate 6101 and the second grid plate 6102.

The first gear 6301 is coaxial with the first grid plate 6101, and the second gear 6302 is coaxial with the second grid plate 6102. Due to the orthogonal and reverse rotation of the synchronous staggered axes of the first gear 6301 and the second gear 6302, the first grid plate 6101 and the second grid plate 6102 can be driven to also be orthogonal and reverse rotation of the synchronous staggered axes.

As shown in fig. 17 and 18, there is provided a three-dimensional cartesian coordinate system conforming to the left-hand rule, which includes X, Y and Z axes perpendicular to each other, and the first grid plate 6101 is rotatable around the X axis in the illustrated coordinate system within a range of 0 ° to 90 °. The second grid plate 6102 is rotatable around the Z-axis in the coordinate system shown, in the range of 0 ° to 90 °. The first grid plate 6101 and the second grid plate 6102 may rotate synchronously, i.e. at the same time, by the same angle.

When the first grid plate 6101 is placed in the horizontal position, i.e., the XZ plane, it is the initial position, and at this time, the first grid plate 6101 is perpendicular to the light beam, the rotation angle is 0 °, and the transmittance of the light beam is in the range of about 80% to 90%. When the first grid plate 6101 is rotated by 45 °, the transmittance of the light beam is in the range of about 10% -20%. The effective continuous adjustment range is within the range of 0-45 degrees of the rotation angle. When the rotation angle of the first grid plate 6101 is 90 °, the first grid plate 6101 rotates out of the range of the light beam, and the transmittance of the light beam at this time is 100%.

When the second grid plate 6102 is placed in the horizontal position, i.e., the XZ plane, it is the initial position, and at this time, the second grid plate 6102 is perpendicular to the light beam, the rotation angle is 0 °, and the transmittance of the light beam is in the range of about 80% to 90%. When the second grid plate 6102 is rotated by 45 °, the transmittance of the light beam is in the range of about 10% -20%. The effective continuous adjustment range is within the range of 0-45 degrees of the rotation angle. When the angle of rotation of the second grid plate 6102 is 90 °, the second grid plate 6102 will turn out the range of the light beam, at which the transmittance of the light beam is 100%.

The first grid plate 6101 and the second grid plate 6102 are provided with grid bars at equal intervals, the grid bars are interlaced with each other to form a plurality of light-transmitting grids, and when passing through the first grid plate 6101 and the second grid plate 6102, the light beams are respectively shielded by the grid bars thereon and pass through the light-transmitting grids. The resulting beam projection will form a spot pattern that is a superposition of the first 6101 and second 6102 grating patterns. Furthermore, the first grid plate 6101 and the second grid plate 6102 are rotated synchronously and alternately, i.e., the rotation angle and the rotation rate are kept in synchronization. The rates of spot pattern transformation by the projection of the light beam caused by the first and

second grid plates

6101 and 6102, respectively, are equal. After passing through the two light beam transmittance adjusting units, the light beams with the transmittance adjusted are emitted through the light-passing holes provided in the outer frame 40. In the whole process of adjusting the light beam transmittance, the light beam does not interfere with the

gears

6301 and 6302.

As shown in fig. 20, the interleaved helical gears are produced using a trapezoidal generated tooth profile generating process. Due to the influence of the stagger angle, the end involute tooth profiles are on different planes and rotate around the shaft in different directions. In their theoretical position, the resulting trapezoid can be placed between two gears. When the resulting gear is moving, both gears are rotating and no transmission errors occur as a result of the kinematic coupling conditions. It should be noted that the shaft angle error may cause the edge contact of the spur gear and the transmission error, and in the case of the shaft helical gear staggered by the shaft angle of 90 °, the influence of the shaft angle error is the smallest because it is located at the point contact. Therefore, the cross shaft helical gear can be set to have a drum shape with a virtual length, so that point contact can be realized, and the sensitivity to shaft angle errors is reduced. Specifically, when the staggered shaft angle is 90 degrees, the contact path of the two gears is 1/4 circular in shape. Besides, the tooth profile surfaces of the two gears are in point contact substantially, and the gear is suitable for the motion working condition with smaller transmission load. The gear pairs are sensitive to changes in center distance but less sensitive to errors in the shaft angle.

Similarly, the embodiment of the present invention also performs a back experiment study and verification on the beam transmittance adjusting apparatus shown in fig. 17 and 18. FIG. 21 is a pupil illumination pattern of the beam transmittance adjustment apparatus shown in FIG. 17 with spot variation with rotation angle, FIG. 22 is a graph of the beam transmittance adjustment apparatus shown in FIG. 17 with respect to transmittance and rotation angle, FIG. 23 is a graph of the derivative of transmittance and rotation angle of the beam transmittance adjustment apparatus shown in FIG. 17, FIG. 24 is a graph of the transmittance and rotation angle with respect to error of the beam transmittance adjustment apparatus shown in FIG. 17, and FIG. 25 is an illumination uniformity evaluation of the beam transmittance adjustment apparatus shown in FIG. 17. The rotation angle θ is an angle of the grid plate rotating in the clockwise direction of the rotation shaft with the vertical beam as a starting point.

To further illustrate the optical effect and pattern of the grating plate in blocking the light beam, fig. 21 shows a series of spot patterns as a function of the rotation angle θ, where each sub-image represents a spot pattern rotated by π/64. It is obvious that as the rotation angle θ is gradually increased, the pattern area of the grid in the spot pattern becomes smaller, and the transmittance of the grid plate is decreased. Fig. 22 shows transmittance versus rotation angle as a function of rotation angle, where the transmittance segment corresponds to a rotation angle theta of 0-45 deg., and the beam transmission grating plate forms a patterning effect. Within the angle range of 0-45 degrees, the corresponding transmittance is respectively 80-20 percent, and the effect of continuously and linearly adjusting the transmittance is formed. As shown in fig. 23, the transmittance of the transmittance adjusting means as a function of the rotation angle is further simulated and described, wherein the grid plate forms a pattern effect in the transmittance section corresponding to the rotation angle θ of 0 to 45 °. Within the angle range of 0-45 degrees, the corresponding transmittance is respectively 80-20 percent, and the effect of continuously and linearly adjusting the transmittance is formed. FIG. 23 b) is a graph of transmittance derivative versus rotation angle to verify monotonicity of the continuously tunable device, wherein the function f (x) should be a continuous monotonically decreasing function. Although the middle end area has a defect 'jump point', namely the transmittance derivative is slightly larger than 0, the transmittance derivatives of the rest areas are all smaller than zero, namely the transmittance can be ensured to be stably reduced when the grid plate rotates along with the angle, and the grid plate is in an excellent adjustable range and performance. As shown in fig. 24, when the transmittance section corresponds to the rotation angle of 0 to 45 °, the error between the error of the transmittance and the theoretical linearity value is less than +/-2%, which means that the decrease of the transmittance is stable and linear when the rotation angle θ of the grid plate is increased in the beam transmittance adjusting apparatus. As shown in fig. 25, when the rotation angle of the grid plate is 0-45 °, the energy ratio curves of the light spot formed by the light beam passing through the grid plate in different areas provide an evaluation means for the uniformity of the light beam, and as can be seen from the energy ratio curves in different areas, the evaluation functions of the four quadrants of the light spot are all lower than 10%, and the optical uniformity is in a better performance range.

Similarly, in order to further ensure that the beam still maintains better uniformity after passing through the grid plate, the embodiment of the present invention performs careful calculation and simulation verification on the specific structure and size of the grid plate in the beam transmittance adjusting device shown in fig. 17. Fig. 26 and 27 are schematic structural views of the first and second grid plates of the light beam adjusting device shown in fig. 17, and referring to fig. 26 and 27, first, in the grid plate, the width v of the grid bars may be set to be in the range of 10nm to 1mm, the width w of the grid bars may be set to be in the range of 10nm to 5mm, the thickness t of the first and second grid plates may be set to be in the range of 10nm to 5mm, the total number of the grid bars may be in the range of 10 to 100000, the ratio of the width v of the grid bars to the width w of the grid bars may be in the range of 0.01 to 1, and the ratio of the width v of the grid bars to the thickness t of the grid plates may be in the range of 0.01 to 1. By reasonably setting the width v of the grid bars, the width w and the width proportion of the grid bars and the range of the proportion of the width v of the grid bars and the thickness t of the grid plate, the penetration area of the grid in the light beam propagation direction can be ensured to be slowly changed in a reasonable range in the tilting process of the grid plate from a vertical light beam to a parallel light beam, the penetration area is unlikely to be rapidly reduced, the light beam transmittance can be ensured to be slowly changed, and the accurate target light beam transmittance can be conveniently obtained according to the adjustment of the tilting angle.

Based on the light beam transmittance adjusting device, the embodiment of the invention also provides an optical illumination system. Fig. 28 and 29 are schematic structural diagrams of two optical illumination systems provided in an embodiment of the present invention, and referring to fig. 28 and 29, the optical illumination system further includes the beam transmittance adjusting apparatus 1 provided in any one of the above embodiments, and further includes a light source system 2, an illumination system 3, and a projection objective 4; the beam transmittance adjusting device 1, the illumination system 3, and the projection objective 4 are sequentially disposed on the optical path of the light beam emitted from the light source system 2. Illustratively, the optical illumination system may be an illumination system of a lithography machine. In other embodiments of this embodiment, the lighting system may also be a lighting system of other equipment, which is not specifically limited in this embodiment.

It is to be noted that the foregoing is only illustrative of the preferred embodiments of the present invention and the technical principles employed. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious modifications, rearrangements, combinations and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. The light beam transmittance adjusting device is characterized by comprising a driving unit and at least one group of transmittance adjusting units, wherein the at least one group of transmittance adjusting units are sequentially arranged along a propagation path of a light beam;

2. The light beam transmittance adjusting apparatus according to claim 1, wherein the light beam transmittance adjusting apparatus comprises a set of the transmittance adjusting units; in the grid plate in the transmittance adjusting unit, the grid bars are arranged in a crossed manner and separated to form the grids which are uniformly distributed.

3. The light beam transmittance adjustment apparatus according to claim 1, characterized in that the light beam transmittance adjustment apparatus includes a first transmittance adjustment unit and a second transmittance adjustment unit; the first transmittance adjusting unit comprises a first grid plate and a first rotating shaft, and the first rotating shaft is parallel to the first grid plate and is fixedly connected with one side of the first grid plate; the second transmittance adjusting unit comprises a second grid plate and a second rotating shaft, and the second rotating shaft is parallel to the second grid plate and is fixedly connected with one side of the second grid plate;

4. The light beam transmittance adjustment apparatus according to claim 3, wherein the first transmittance adjustment unit further comprises a first gear, and the second transmittance adjustment unit further comprises a second gear; the first gear and the second gear are mutually meshed staggered shaft helical gears, and a rotating shaft of the first gear is vertical to a rotating shaft of the second gear;

5. The apparatus according to claim 3, wherein the width of the grid bars ranges from 10nm to 1mm, the width of the grids ranges from 10nm to 5mm, the thickness of the first grid plate and the second grid plate ranges from 10nm to 5mm, the total number of the grids ranges from 10 to 100000, the ratio of the width of the grid bars to the width of the grids ranges from 0.01 to 1, and the ratio of the width of the grid bars to the thickness of the grid plates ranges from 0.01 to 1.

6. The apparatus for adjusting transmittance of light beams according to claim 2, wherein the width of the grating bars is in the range of 10nm to 1mm, the width of the grids is in the range of 10nm to 5mm, the thickness of the grid plates is in the range of 10nm to 5mm, the total number of the grids is in the range of 10 to 100000, the ratio of the width of the grating bars to the width of the grids is in the range of 0.001 to 1000, and the ratio of the width of the grating bars to the thickness of the grid plates is in the range of 0.001 to 1000.

7. The beam transmittance adjustment apparatus according to claim 2, wherein the grid pattern in the grid plate is any one of a polygon, a circle, an ellipse, and a fan.

8. The beam transmittance adjustment apparatus according to claim 2, wherein the grid plate is a square plate, and the rotation axis is perpendicular to a diagonal line of the grid plate.

9. The beam transmittance adjustment device according to claim 1, wherein when the angle between the grid plate and the propagation direction of the beam is 90 °, the transmittance of the grid plate is 80%; when the included angle between the grid plate and the propagation direction of the light beam is 45 degrees, the transmittance of the grid plate is 20 percent.

10. The light beam transmittance adjusting apparatus according to claim 1, wherein the driving unit includes a motor, a coupling, and a decoder;

11. The light beam transmittance adjustment apparatus according to claim 1, wherein the transmittance adjustment unit further comprises a frame in which the grid plate is disposed;

12. The apparatus according to claim 1, wherein the apparatus further comprises a frame, and light-passing holes are respectively formed at two opposite sides of the frame to pass through the light beam;

13. The apparatus according to claim 12, further comprising a heat dissipating unit disposed on an outer wall of the outer frame.

14. The device for adjusting the transmittance of light beams according to claim 1, wherein the grid plate comprises a substrate and a grid layer arranged on one side surface of the substrate, the grid layer comprises a plurality of grids, and the grids are separated to form a plurality of grids which are uniformly distributed;

15. The beam transmittance adjustment device of claim 14, wherein the grid plate is prepared by a 3D printing process or a photolithography process.

16. An optical illumination system comprising the light beam transmittance adjusting apparatus according to any one of claims 1 to 15, further comprising a light source system, an illumination system, a projection objective lens;