Focus adjustment structure and projection optical machine

Abstract

The present invention provides a focusing structure and a projection optical machine. The focusing structure includes a lens, a sleeve, a focusing member, and a driving member. The sleeve is sleeved on the outer circumferential wall of the lens. An inclined groove is provided on the sleeve, and at least two focusing holes are provided on the outer circumferential wall of the lens. There is a distance difference among the at least two focusing holes along the central axis direction of the lens. The focusing member passes through the inclined groove and can be detachably connected to any one of the focusing holes. The driving member is connected to the focusing member to drive the focusing member to slide along the inclined groove, and then drive the lens to rotate through the focusing member to move the lens along the central axis of the lens to achieve focusing. Through the design of the structural features, this focusing structure compensates for the technical problems of low focusing accuracy and difficult focusing efficiency caused by the cumulative tolerances in processing and assembly, thereby improving the focusing accuracy and focusing efficiency of the lens, and improving the imaging quality of the projection system and the user experience.

Description

Technical Field

[0001] The present invention relates to the technical field of focusing structures, and in particular, to a focusing structure and a projection optical machine. Background Art

[0002] In micro-projection technology, the projection focusing distance includes an optical focusing distance and a structural focusing tolerance redundancy. The structural focusing tolerance includes cumulative tolerances in machining and assembly. When the optical focusing distance in the focusing structure is short and its proportion in the total stroke is small, most of the projection focusing is used for empty running without achieving the effective function of adjusting the imaging to be clear. Reducing the focusing empty running can be achieved by reducing the structural focusing tolerance redundancy. However, setting too small a structural focusing tolerance will cause the actual cumulative structural tolerance to be greater than the designed value, resulting in insufficient focusing stroke, that is, when the focusing reaches the extreme end that can be reached, the projection image is not yet adjusted clearly or has not reached the best state. Therefore, to avoid insufficient focusing stroke, design redundancies for cumulative tolerances in machining and assembly are added within the effective focusing range.

[0003] In a projection system, when the designed distance of the optical focusing stroke is small and the proportion of the optical effective focusing stroke in the total focusing stroke is too small, the focusing accuracy will decrease. The clearest projection image cannot be well presented due to focusing accuracy factors, resulting in a decline in the quality of the projection imaging. In addition, when the proportion of the effective focusing stroke in a large focusing stroke is too small, users need a long time for focusing and adjusting, with low focusing efficiency, making the focusing difficult and resulting in a poor user experience.

[0004] In view of this, it is necessary to provide a new focusing structure and a projection optical machine to solve or at least alleviate the above technical defects. Summary of the Invention

[0005] The main object of the present invention is to provide a focusing structure and a projection optical machine, aiming to solve the technical problems of low focusing accuracy and low focusing efficiency caused by cumulative tolerances in machining and assembly in the existing focusing structure.

[0006] To achieve the above object, according to one aspect of the present invention, a focusing structure is provided, which includes a lens, a sleeve, a focusing member, and a driving member. The sleeve is sleeved on the outer circumferential wall of the lens. An inclined groove is provided on the sleeve. At least two focusing holes are provided on the outer circumferential wall of the lens, and there is a distance difference between at least two of the focusing holes along the central axis direction of the lens. The focusing member passes through the inclined groove and can be detachably connected to any one of the focusing holes. The driving member is connected to the focusing member to drive the focusing member to slide along the inclined groove, and then drive the lens to rotate through the focusing member to move the lens along the central axis of the lens to achieve focusing.

[0007] In one embodiment, the lens includes a lens barrel and an adjustment block, a mounting groove is formed on the lens barrel, the adjustment block is installed in the mounting groove, the sleeve is sleeved on the lens barrel, the oblique groove is arranged corresponding to the adjustment block, and at least two focusing holes are arranged on the adjustment block.

[0008] In one embodiment, the number of the focusing holes is three, and there is a distance difference between each of the three focusing holes along the central axis direction of the lens barrel.

[0009] In one embodiment, the three focusing holes are respectively a center hole, a first peripheral hole and a second peripheral hole. In the length direction of the adjustment block, the first peripheral hole and the second peripheral hole are respectively arranged on both sides of the center hole; along the central axis direction of the lens barrel, the first peripheral hole, the center hole and the second peripheral hole are arranged in sequence.

[0010] In one embodiment, the focusing member is a screw, the focusing hole is a threaded hole, and the screw is detachably connected to the adjustment block through the threaded hole.

[0011] In one embodiment, the driving member includes a driving motor, a gear and a rack, the driving motor is transmission-connected to the gear, the gear is meshed with the rack, a slot is formed on a side of the rack away from the gear, and an end of the focusing member away from the focusing hole is connected to the slot.

[0012] In one embodiment, in the moving direction of the rack, the focusing member abuts against two side edges of the slot respectively, and in the direction of the central axis of the lens, a gap is provided between the focusing member and the slot.

[0013] In one embodiment, a moving groove is formed on the sleeve, the inclined groove passes through the bottom of the moving groove, and the rack is slidably installed in the moving groove.

[0014] In one embodiment, the focusing structure further includes a bracket, the driving member is mounted on the bracket, an avoidance groove for the rack to slide is formed on the bracket, and the bracket is detachably connected to the sleeve.

[0015] According to another aspect of the present invention, the present invention further provides a projection optical machine, wherein the projection optical machine comprises the above-mentioned focusing structure.

[0016] In the above solution, the driving member can drive the focusing member to move along the inclined groove. At this time, the movement of the focusing member is the synthesis of two-direction movements. One movement direction is the circumferential movement along the outer circumferential wall of the lens, and the other is the axial movement along the central axis direction of the lens. The circumferential movement drives the lens to rotate, and the axial movement is used to drive the lens to move along its own central axis to achieve the adjustment of the focal length. By providing at least two focusing holes in the lens, and the focusing member can be detachably connected to one of the focusing holes. In this way, when the focusing movement distance is reduced, if the focusing member still cannot reach the best state of projection imaging at the limit position at the left end of the inclined groove due to the cumulative tolerance of processing and assembly, that is, when the cumulative tolerance of processing and assembly shifts to the left direction, the focusing member can be removed and assembled onto the left reserved focusing hole to compensate for the insufficient left focusing stroke caused by the left shift of the cumulative tolerance of processing and assembly, so as to ensure that the projection focusing structure has enough distance to be adjusted to the best state. Similarly, if the focusing member still cannot reach the best state of projection imaging at the limit position at the right end of the inclined groove due to the cumulative tolerance of processing and assembly, that is, when the cumulative tolerance of processing and assembly shifts to the right direction, the focusing member can be removed and assembled onto the right reserved focusing hole to compensate for the insufficient right focusing stroke caused by the right shift of the cumulative tolerance of processing and assembly, so as to ensure that the projection focusing structure has enough distance to be adjusted to the best state. The invention compensates for the technical problems of low focusing accuracy and difficult focusing efficiency caused by the cumulative tolerance of processing and assembly through structural features, thereby improving the focusing accuracy and focusing efficiency of the lens, and improving the imaging quality and user experience of the projection system. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on the structures shown in these drawings.

[0018] Figure 1 A three-dimensional structure diagram of the focusing structure according to an embodiment of the present invention;

[0019] Figure 2 A structural diagram of a perspective view of the focusing structure according to an embodiment of the present invention;

[0020] Figure 3 A structural diagram of the lens, sleeve and rack according to an embodiment of the present invention;

[0021] Figure 4 A structural diagram of the lens, sleeve and focusing member according to an embodiment of the present invention;

[0022] Figure 5 A structural diagram of the adjusting block, focusing hole and lens barrel according to an embodiment of the present invention;

[0023] Figure 6 Schematic structural diagram of the rack and focusing member according to an embodiment of the present invention;

[0024] Figure 7 Schematic structural diagram of the adjusting block according to an embodiment of the present invention;

[0025] Figure 8 Schematic diagram of the distribution of the focusing holes according to an embodiment of the present invention;

[0026] Figure 9 Schematic diagram of the focusing travel redundancy required for the cumulative tolerance of lens component processing and assembly and the optical focusing distance of the lens.

[0027] Reference numeral description:

[0028] 1. Focusing member; 2. Lens; 21. Lens barrel; 22. Adjusting block; 23. Installation groove; 3. Sleeve; 31. Inclined groove; 32. Moving groove; 4. Driving member; 41. Driving motor; 42. Gear; 43. Rack; 431. Card slot; 5. Focusing hole; 51. First peripheral hole; 52. Central hole; 53. Second peripheral hole; 6. Bracket; 61. Avoidance groove.

[0029] The realization, functional features and advantages of the object of the present invention will be further described in conjunction with the embodiments with reference to the accompanying drawings. Specific embodiments

[0030] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0031] It should be noted that all the directional indications (such as up, down...) in the embodiments of the present invention are only used to explain the relative positional relationship and movement conditions between components in a specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indications will also change accordingly.

[0032] In addition, the descriptions such as "first" and "second" in the present invention are only for descriptive purposes, and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features.

[0033] Moreover, the technical solutions between various embodiments of the present invention can be combined with each other, but it must be based on the fact that those skilled in the art can implement it. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0034] Referring to Figures 1 to 8 , according to one aspect of the present invention, the present invention provides a focusing structure, including a lens 2, a sleeve 3, a focusing member 1, and a driving member 4. The sleeve 3 is sleeved on the outer circumferential wall of the lens 2. An inclined slot 31 is provided on the sleeve 3. At least two focusing holes 5 are provided on the outer circumferential wall of the lens 2. There is a distance difference among the at least two focusing holes 5 in the direction of the central axis of the lens 2. The focusing member 1 passes through the inclined slot 31 and can be detachably connected to any one of the focusing holes 5. The driving member 4 is connected to the focusing member 1 to drive the focusing member 1 to slide along the inclined slot 31, and then drive the lens 2 to rotate through the focusing member 1 to move the lens 2 along the central axis of the lens 2 to achieve focusing.

[0035] It should be noted that, usually, referring to Figure 9 , the axial movement distance of the lens 2 includes the effective focusing distance required for focusing and the cumulative tolerance redundancy due to the machining tolerance and assembly tolerance of components. When the optical focusing distance designed for the lens 2 is short, the proportion of the optical focusing distance in the total stroke is low. The focusing accuracy α of the focusing structure = (S1 + S2) / n, where S1 is the optical focusing distance of the lens 2, S2 is the focusing stroke redundancy required for the cumulative tolerance of the machining and assembly of the lens 2 components; n is the number of pulses required for the motor to complete the full stroke of focusing. n is related to the motor selection and the gear train. When the motor and the gear train are confirmed, the focusing accuracy can be improved by reducing the focusing movement distance (the focusing movement distance is S1 + S2). However, if the focusing movement distance is directly reduced, it may not be able to fully compensate for S2, or the focusing distance S1 is insufficient after compensating S2 for the focusing movement distance, which will result in insufficient stroke. The phenomenon is that the focusing member 1 has reached the limit positions at both ends of the inclined slot 31, but the lens imaging has not been adjusted clearly or has not reached the best state of the lens imaging.

[0036] In this embodiment, the driving member 4 can drive the focusing member 1 to move along the inclined groove 31. At this time, the movement of the focusing member 1 is the synthesis of two-directional movements. One movement direction is the circumferential movement along the outer circumferential wall of the lens 2, and the other is the axial movement along the central axis direction of the lens 2. The circumferential movement drives the lens 2 to rotate, and the axial movement is used to drive the lens 2 to move along its own central axis to adjust the focal length. By providing at least two focusing holes 5 in the lens 2, and the focusing member 1 can be detachably connected to any one of the focusing holes 5. In this way, when the focusing movement distance is reduced, if the focusing member 1 still cannot reach the optimal state of projection imaging at the extreme left position of the inclined groove 31 due to the cumulative tolerance of processing and assembly, that is, when the cumulative tolerance of processing and assembly shifts to the left direction, the focusing member 1 can be removed and assembled to the left reserved focusing hole 5 (referring to the focusing hole 5 on the left side among at least two focusing holes 5, such as Figure 4 the first peripheral hole 51 in Figure 4 ), to compensate for the insufficient left focusing stroke caused by the cumulative tolerance of processing and assembly shifting to the left, so as to ensure that the projection focusing structure has enough distance to be adjusted to the optimal state. Similarly, if the focusing member 1 still cannot reach the optimal state of projection imaging at the extreme right position of the inclined groove 31 due to the cumulative tolerance of processing and assembly, that is, when the cumulative tolerance of processing and assembly shifts to the right direction, the focusing member 1 can be removed and assembled to the right reserved focusing hole 5 (referring to the focusing hole 5 on the right side among at least two focusing holes 5, such as

[0037] the first peripheral hole 53 in Figure 5 ), to compensate for the insufficient right focusing stroke caused by the cumulative tolerance of processing and assembly shifting to the right, so as to ensure that the projection focusing structure has enough distance to be adjusted to the optimal state. This embodiment compensates for the technical problems of low focusing accuracy and difficult focusing efficiency caused by the cumulative tolerance of processing and assembly through the design of structural features, thereby improving the focusing accuracy and focusing efficiency of the lens 2, and improving the imaging quality and user experience of the projection system.

[0037] See Figure 5, in one embodiment, the lens 2 includes a lens barrel 21 and an adjustment block 22. An installation groove 23 is formed on the lens barrel 21, and the adjustment block 22 is installed in the installation groove 23. A sleeve 3 is sleeved on the lens barrel 21, and an inclined groove 31 is provided corresponding to the adjustment block 22. At least two focusing holes 5 are provided on the adjustment block 22. Of course, the lens 2 also includes lenses installed on the lens barrel 21. Since the lens barrel 21 has high cost and precision requirements, and expensive lenses are installed. If the focusing holes 5 are directly provided on the lens barrel 21, the precision of the lens 2 and the lenses may be affected during the manufacturing and adjustment processes, and the lens barrel 21 and the lenses are easily damaged. Therefore, by providing a recessed installation groove 23 along the outer wall of the lens barrel 21 on the lens barrel 21, the adjustment block 22 is arranged in the installation groove 23, and the form of providing at least two focusing holes 5 on the adjustment block 22 is used to avoid directly providing the focusing holes 5 on the lens barrel 21. During the movement of the focusing member 1, the adjustment block 22 will drive the lens barrel 21 to move together. At the same time, when the threads of the focusing holes 5 are stripped due to repeated use or there are other failure modes, only the adjustment block 22 needs to be replaced without replacing the entire lens barrel 21 and the lenses, reducing the maintenance cost.

[0038] See Figure 5 , Figure 7 and Figure 8 , in one embodiment, the number of the focusing holes 5 is three, and there is a distance difference between every two of the three focusing holes 5 along the central axis direction of the lens barrel 21. Specifically, we name the three focusing holes 5 as the central hole 52, the first peripheral hole 51, and the second peripheral hole 53 respectively. It should be noted that what is expressed here is that the central hole 52, the first peripheral hole 51, and the second peripheral hole 53 each refer to the focusing hole 5 alone, and naming them different names is only for convenience of description. Specifically, in the length direction of the adjustment block 22, the first peripheral hole 51 and the second peripheral hole 53 are respectively arranged on both sides of the central hole 52; along the central axis direction of the lens barrel 21, the first peripheral hole 51, the central hole 52, and the second peripheral hole 53 are arranged in sequence. Here, it is stated that while the three focusing holes 5 are arranged circumferentially along the lens barrel 21, there is an offset distance in the axial direction of the lens barrel 21. In this way, when it is necessary to replace the focusing hole 5 that cooperates with the focusing member 1, the required focusing hole 5 can be rotated to the position of the inclined groove 31 by rotating the lens barrel 21, facilitating the connection between the focusing member 1 and the focusing hole 5. At the same time, for convenience of adjustment, it is arranged that along the central axis direction of the lens barrel 21, the first peripheral hole 51, the central hole 52, and the second peripheral hole 53 are arranged in sequence, which is convenient for adjustment. Refer to Figure 4, for example, when the focusing member 1 is located at the central hole 52, it is found that when the focusing moving distance is reduced, if the focusing member 1 still cannot reach the best state of projection imaging at the left end limit position of the inclined groove 31 due to the cumulative tolerance of machining and assembly, that is, when the cumulative tolerance of machining and assembly shifts to the left direction, the operator knows to remove the focusing member 1 and assemble it onto the first peripheral hole 51 on the left. Similarly, when the focusing member 1 still cannot reach the best state of projection imaging at the right end limit position of the inclined groove 31, the focusing member 1 can be removed and assembled onto the second peripheral hole 53 on the right.

[0039] To clearly illustrate the principle of the present invention, the following is a specific description. Refer to Figure 8 , assuming that the distances between the central hole 52 and the first peripheral hole 51 and the second peripheral hole 53 in the central axis direction of the lens 2 (i.e., the optical axis of the lens 2) are both △ L, △ The distance value of L can be used to compensate for the focusing travel redundancy s2 required for the cumulative tolerance of the lens 2 component machining and assembly. That is, by adding a first peripheral hole 51 and a second peripheral hole 53 with a distance of ± △ L along the central axis of the lens 2 on both sides of the central hole 52, the focusing travel redundancy s2 required for the cumulative tolerance of the lens 2 component machining and assembly can be reduced to △ s = s2 - 2 * ΔL; the focusing accuracy α can be increased to α' = (s1 + Δs) / n = α - 2 * ΔL / n. Therefore, the focusing accuracy can be improved through structural compensation, and the imaging clarity can be enhanced.

[0040] Refer to Figures 4 to 6 , in an embodiment, the focusing member 1 is a screw, and the focusing hole 5 is a threaded hole. The screw is detachably connected to the adjusting block 22 through the threaded hole. Using screw connection has high installation strength, is convenient for disassembly, and has low manufacturing cost.

[0041] Refer to Figure 1 、 Figure 2 and Figure 6In one embodiment, the driving member 4 includes a driving motor 41, a gear 42 and a rack 43. The driving motor 41 is transmission-connected to the gear 42. The gear 42 is meshed with the rack 43. A slot 431 is formed on the side of the rack 43 away from the gear 42. The end of the focusing member 1 away from the focusing hole 5 is connected to the slot 431. For the driving member 4, the step angle of the driving motor 41 is θ; the reduction ratio of the motor reduction box gear 42 is i1, the number of teeth of the motor gear 42 is z1, the number of teeth of the rack 43 is z2, and the gear system number ratio is i1=z1 / z2; the focusing rotation angle of the lens 2 is φ, then the number of pulses required for the driving motor 41 to complete the focusing process is n=φ / (θ*i1), or when there is an external gear meshing with the gear 42, the reduction ratio is i2, then n=φ / (θ*i1*i2), combined with the focusing accuracy α=(S1+S2) / n, it can be seen that when the driving motor 41 and the gear 42 are selected or the total number of focusing pulses is constant, the focusing accuracy can be improved by reducing the focusing moving distance. The driving motor 41 drives the gear 42 to rotate, and then the gear 42 drives the rack 43 meshing with the gear 42 to move, and finally achieves the purpose of driving the focusing member 1 to move.

[0042] Specifically, refer to Figure 3 The sleeve 3 is formed with a moving groove 32, the inclined groove 31 passes through the groove bottom of the moving groove 32, and the rack 43 is slidably mounted in the moving groove 32. The length of the moving groove 32 is greater than the length of the rack 43, the moving groove 32 is an arc groove adapted to the outer peripheral wall of the sleeve 3, and the rack 43 can be an arc bar, which is convenient for sliding in the moving groove 32 of the sleeve 3.

[0043] See also Figure 6 In one embodiment, in the moving direction of the rack 43, the focus member 1 abuts against both sides of the slot 431, and a gap is provided between the focus member 1 and the slot 431 in the direction of the central axis of the lens 2. In the moving direction of the rack 43, the focus member 1 abuts against both sides of the slot 431 so that the focus member 1 can be driven to move by the movement of the rack 43. Since the sleeve 3 has an inclined groove 31, the inclined groove 31 is not distributed along the circumference of the lens barrel 21, and the focus member 1 needs to be displaced along the central axis of the lens 2 to adjust the focal length, a gap is provided between the focus member 1 and the slot 431 in the direction of the central axis of the lens 2, so that the focus member 1 can move in the slot 431 along the central axis of the lens 2.

[0044] See also Figure 1 and Figure 2, in one embodiment, the focusing structure further includes a bracket 6, the driving member 4 is installed on the bracket 6, an avoidance groove 61 for the rack 43 to slide is formed on the bracket 6, and the bracket 6 is detachably connected to the sleeve 3. The bracket 6 and the sleeve 3 can be detachably connected by a threaded member, which is convenient for disassembly and replacement. The formation of the avoidance groove 61 on the bracket 6 is to prevent the bracket 6 from interfering with the sliding of the rack 43 on the moving groove 32.

[0045] According to another aspect of the present invention, the present invention further provides a projection optical machine, and the projection optical machine includes the above-mentioned focusing structure. Since the projection optical machine includes all the technical solutions of all the embodiments of the above-mentioned focusing structure, it at least has all the beneficial effects brought by the above-mentioned all technical solutions, and will not be elaborated here one by one.

[0046] The above are only optional embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structural transformation made by using the description and drawings of the present invention under the technical concept of the present invention, or direct / indirect application in other related technical fields, is included in the patent protection scope of the present invention.

Claims

1. A focusing structure, characterized in that, It includes a lens, a sleeve, a focusing member and a driving member. The sleeve is sleeved on the outer circumferential wall of the lens. An inclined groove is provided on the sleeve. At least two focusing holes are provided on the outer circumferential wall of the lens. The at least two focusing holes are arranged along the circumferential direction of the lens. There is a distance difference among the at least two focusing holes in the direction of the central axis of the lens. The focusing member passes through the inclined groove and can be detachably connected to any one of the focusing holes. The driving member is connected to the focusing member to drive the focusing member to slide along the inclined groove, and then drive the lens to rotate through the focusing member so that the lens moves along the central axis of the lens to achieve focusing.

2. The focusing structure according to claim 1, characterized in that, The lens includes a lens barrel and an adjusting block. An installation groove is formed on the lens barrel. The adjusting block is installed in the installation groove. The sleeve is sleeved on the lens barrel. The inclined groove corresponds to the adjusting block. At least two of the focusing holes are provided on the adjusting block.

3. The focusing structure according to claim 2, wherein The number of the focusing holes is three, and there is a distance difference between any two of the three focusing holes in the direction of the central axis of the lens barrel.

4. The focusing structure according to claim 3, characterized in that, The three focusing holes are respectively a central hole, a first peripheral hole and a second peripheral hole. In the length direction of the adjusting block, the first peripheral hole and the second peripheral hole are respectively arranged on both sides of the central hole; along the central axis direction of the lens barrel, the first peripheral hole, the central hole and the second peripheral hole are arranged in sequence.

5. The focusing structure according to claim 2, characterized in that The focusing member is a screw, the focusing hole is a threaded hole, and the screw is detachably connected to the adjusting block through the threaded hole.

6. The focusing structure according to any one of claims 1 to 5, characterized in that, The driving member includes a driving motor, a gear and a rack. The driving motor is in transmission connection with the gear. The gear meshes with the rack. A clamping slot is formed on one side of the rack away from the gear. One end of the focusing member away from the focusing hole is connected to the clamping slot.

7. The focusing structure according to claim 6, wherein, In the moving direction of the rack, the focusing member abuts against both side edges of the clamping slot respectively. In the direction of the central axis of the lens, a gap is provided between the focusing member and the clamping slot.

8. The focusing structure according to claim 6, wherein A moving groove is formed on the sleeve. The inclined groove penetrates the bottom of the moving groove. The rack is slidably installed in the moving groove.

9. The focusing structure according to claim 6, wherein, The focusing structure further includes a bracket. The driving member is installed on the bracket. An avoidance groove for the rack to slide is formed on the bracket. The bracket is detachably connected to the sleeve.

10. A projection optical machine, characterized in that, The projection optical machine includes the focusing structure according to any one of claims 1 to 9.

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