A focusing structure applied to a short-focus projection device

Abstract

The utility model discloses a kind of focusing structure applied to short-focus projection equipment, including stepper motor, mounting bracket;Stepper motor is connected with mounting bracket by adjusting screw rod;Adjusting screw rod outer periphery is equipped with adjusting knob, adjusting knob can reciprocate along adjusting screw rod;Mounting bracket includes installation bottom plate and front mounting plate, rear mounting plate;One end of adjusting screw rod is connected with rear mounting plate center, another end is threaded through front mounting plate, and is connected with stepper motor transmission;The end of adjusting knob towards installation bottom plate is equipped with the limit slot of the cylindrical connecting piece of lens module plug-in connection;9 degrees stepper motor is used in the application, and it is matched with precision adjusting screw rod, meet the short focusing stroke of ultra-short-focus projection equipment, high-precision demand, fine adjustment resolution reaches 0.005mm / step, focusing process is fine controllable, applicable to focusing stroke short, ultra-short-focus projection equipment of adjusting precision high;And preset connecting piece, realize quick, reliable mechanical connection, assembly efficiency is significantly improved.

Description

Technical Field

[0001] This utility model relates to the field of projection equipment technology, and in particular to a focusing structure applied to short-throw projection equipment. Background Technology

[0002] Currently, with the continuous development of consumer electronics, ultra-short-throw projection devices are widely used in micro-display systems and portable projectors due to their advantages such as small size, short projection distance, and suitability for confined spaces. In such systems, the focusing mechanism, as a key component affecting image clarity, directly determines display quality and user experience through its structural performance and control precision. Taking ultra-short-throw projection devices as an example, their short focusing stroke places higher demands on displacement control precision, response speed, and structural size. However, the focusing process of existing stepper motors and lead screw propulsion structures cannot meet the precision control requirements of ultra-short-throw systems, resulting in problems such as blurred images or unstable focusing. In addition, existing stepper motors often require increased motor size to improve output force, which is not conducive to the integration of small projection modules and cannot meet the design requirements of ultra-short-throw projection devices for a thin and compact structure. At the same time, the guide structure often suffers from high friction and poor stability, which is not conducive to achieving high-speed, low-noise linear displacement control.

[0003] Furthermore, in terms of compatibility with the assembly structure of projection equipment, most focusing mechanisms on the market have not achieved modular and standardized design. Their mechanical interfaces, electromagnetic structures and guiding mechanisms need to be redesigned and adjusted according to the whole system. They cannot be directly adapted to the internal structure of projection equipment, and additional connecting parts need to be customized. The installation process is cumbersome and increases the complexity of system development and assembly.

[0004] Therefore, further research and development is needed on miniature electromagnetic drive structures that are compact, have sufficient thrust, high focusing accuracy, and good adaptability to solve the technical problems existing in the above-mentioned technologies. Utility Model Content

[0005] Therefore, in order to solve the problems existing in the prior art, the purpose of this utility model is to provide a focusing structure for short-throw projection devices.

[0006] To achieve the above objectives, this utility model provides the following technical solution:

[0007] A focusing structure for use in a short-throw projection device, used to connect to the lens module of the projection device, the lens module having a cylindrical connector; it includes a stepper motor and a mounting bracket coaxially arranged; the stepper motor is drivenly connected to the mounting bracket via an adjusting screw; an adjusting block is sleeved on the outer periphery of the adjusting screw, the adjusting block being reciprocating along the adjusting screw; the mounting bracket includes a mounting base plate and a front mounting plate and a rear mounting plate located on both sides of the base plate; one end of the adjusting screw is connected to the center of the rear mounting plate, and the other end passes through the front mounting plate and is drivenly connected to the stepper motor; the adjusting block is located between the front mounting plate and the rear mounting plate and reciprocates along the adjusting screw; the end of the adjusting block facing the mounting base plate has a limiting groove for engaging with the cylindrical connector of the lens module, and the mounting base plate has an adjusting hole corresponding to the limiting groove.

[0008] To further explain, the adjustment hole is a strip-shaped adjustment hole extending along the direction of movement of the adjustment lever, and the length of the adjustment hole matches the focusing stroke of the lens module.

[0009] To further explain, the mounting bracket is provided with a guide rod, and the two ends of the guide rod are respectively connected to the front mounting plate and the rear mounting plate; the adjusting block is provided with a guide hole that matches the guide rod, and is slidably connected to the guide rod through the guide hole.

[0010] To further clarify, the stepper motor has a step angle of 9 degrees; the adjusting screw has a pitch of 0.2 mm.

[0011] Further explanation: The stepper motor includes a front housing, a rear housing, and a stator assembly and a rotor assembly disposed between the front housing and the rear housing; the rotor assembly includes a cylindrical magnet sleeved on the outer periphery of the adjusting screw and driving the adjusting screw to rotate, the magnet being sleeved on the outer periphery of the adjusting screw; the stator assembly includes a winding frame sleeved on the outer periphery of the magnet and a coil wound on the outer periphery of the winding frame; when the coil is energized, it drives the magnet to drive the adjusting screw to rotate.

[0012] To further explain, the winding frame has winding portions at both ends for mounting the coil. The front end housing and the rear end housing are respectively provided with mounting grooves that engage with the winding portions at their ends facing the winding frame, and are respectively mounted at both ends of the winding frame through the cooperation of the mounting grooves with the winding portions. The outer side of the rear end housing is provided with a fixed bottom cover. The end of the adjusting screw near the rear end housing is fitted with a bottom cover bearing.

[0013] To further explain, a limiting spring is provided between the fixed bottom cover and the bottom cover bearing. The center of the limiting spring is provided with a pressing spring that protrudes toward the adjusting screw. The pressing spring is fixed to the end of the adjusting screw near the rear end housing.

[0014] To further explain, the mounting bracket is integrally bent from a metal plate, and the front mounting plate, rear mounting plate, and mounting base plate have U-shaped or inverted C-shaped cross sections.

[0015] To further explain, the center of the front mounting plate is provided with a through hole for connecting with the adjusting screw, and the end of the adjusting screw is installed in the through hole by a bearing or a pad.

[0016] To further explain, the mounting base plate is provided with several connecting holes, which are used to connect to the lens module of the projection device through fasteners.

[0017] Compared with the prior art, the beneficial effects of this utility model are at least in the following aspects:

[0018] 1) The stepper motor, adjusting screw, adjusting lever and other components of this utility model are arranged coaxially, and the overall structure is highly integrated and small in size; it meets the requirements of short focusing stroke and high precision of ultra-short throw projection equipment, and is suitable for micro projection modules with extremely strict requirements for space layout and weight.

[0019] Furthermore, the adjusting block is equipped with a limiting groove structure. The bottom of the adjusting block is also equipped with a limiting groove structure. The structural dimensions of the limiting groove match the cylindrical connector on the projection equipment lens module. Users only need to insert the cylindrical connector into the limiting groove to achieve a quick and reliable mechanical connection, significantly improving assembly efficiency. At the same time, by eliminating intermediate connectors and redundant structures, the entire machine is optimized in terms of material usage, inventory management, and manual operation, thereby effectively reducing the overall cost of the product in the design, production, and after-sales stages, and improving the efficiency and consistency of mass production.

[0020] 2) The focusing structure of this utility model adopts an electromagnetic drive motor with a step angle of 9 degrees, combined with a precision adjusting screw with a pitch of 0.2mm. The adjusting screw is connected to the adjusting block through a thread, realizing the conversion of rotational motion into linear displacement. Each step of the motor can precisely drive the adjusting block to make a small advancing or retracting movement along the screw axis, thereby driving the lens holder to achieve fine back and forth movement and complete the precise adjustment of the focal length. This utility model has high fine-tuning resolution, reaching 0.005mm / step, and the focusing process is precise and controllable. It is especially suitable for ultra-short-throw projection equipment with short focusing stroke and high adjustment accuracy. Attached Figure Description

[0021] Figure 1This is a schematic diagram of the overall structure of the focusing structure applied to a short-throw projection device, which is a preferred embodiment of the present invention.

[0022] Figure 2 This is a schematic diagram of the overall structure of the focusing structure of a short-throw projection device, which is a preferred embodiment of the present invention.

[0023] Figure 3 This is a schematic cross-sectional view of the overall structure of the focusing structure applied to a short-throw projection device, according to a preferred embodiment of the present invention.

[0024] Figure 4 This is an exploded view of the overall structure of the focusing structure applied to a short-throw projection device, according to a preferred embodiment of the present invention.

[0025] Figure 5 This is a physical reference diagram of the focusing structure and lens module assembly state of a preferred embodiment of the present invention applied to a short-throw projection device;

[0026] Figure 6 This is a physical reference diagram of a lens module assembled with a focusing structure in a short-throw projection device, as per a preferred embodiment of this utility model.

[0027] In the picture:

[0028] 1. Stepper motor; 11. Front housing; 12. Rear housing; 13. Stator assembly; 131. Winding frame; 1311. Winding section; 132. Coil; 14. Rotor assembly; 141. Magnet; 15. Fixed bottom cover; 16. Bottom cover bearing; 17. Limiting spring; 171. Pressing spring; 2. Mounting bracket; 21. Mounting base plate; 211. Adjustment hole; 212. Connection hole; 22. Front mounting plate; 221. Through hole; 23. Rear mounting plate; 3. Adjusting screw; 4. Adjusting lever; 41. Limiting groove; 42. Guide hole; 5. Guide rod. Detailed Implementation

[0029] To facilitate understanding of this utility model, the technical solution and advantages of the utility model will be further described in detail below with reference to the accompanying drawings and embodiments. The specific structure and features of this utility model are illustrated by way of example and should not constitute any limitation on this utility model. Furthermore, any of the technical features mentioned below (including implicit or disclosed features), as well as any technical features directly shown or implied in the figures, can be arbitrarily combined or deleted among these technical features to form other embodiments that may not be directly or indirectly mentioned in this utility model. The accompanying drawings show preferred embodiments of this utility model. However, this utility model can be implemented in many different forms and is not limited to the embodiments described herein.

[0030] In the description of this utility model, unless otherwise stated, all components used are conventional components in the prior art.

[0031] like Figure 1-6 As shown, this utility model provides a focusing structure for use in short-throw projection devices, used to connect with the lens module of the projection device. The lens module is provided with a cylindrical connector. It includes a stepper motor 1 and a mounting bracket 2 arranged coaxially. The stepper motor 1 is connected to the mounting bracket 2 via an adjusting screw 3. Specifically, the step angle of the stepper motor 1 is 9 degrees; the pitch of the adjusting screw 3 is 0.2 mm; and the mounting bracket 2 is integrally bent from a metal plate, and the front mounting plate 22, the rear mounting plate 23 and the mounting base plate 21 have U-shaped or inverted C-shaped cross sections.

[0032] In this embodiment, an electromagnetic drive motor with a step angle of 9 degrees is used, combined with a precision adjusting screw with a pitch of 0.2 mm. The adjusting screw is threadedly connected to the adjusting block, realizing the conversion of rotational motion into linear displacement. Each step of the motor can precisely drive the adjusting block to make a small advancing or retracting movement along the screw axis, thereby driving the lens holder to achieve fine back-and-forth movement and complete the precise adjustment of the focal length. This utility model can achieve ultra-small displacement controllable in one step, with high fine-tuning resolution, reaching 0.005 mm / step. The focusing process is precise and controllable with high resolution, making it particularly suitable for ultra-short-throw projection equipment with short focusing stroke and high adjustment accuracy. Furthermore, the mounting bracket adopts a one-piece metal bending molding method, making the overall structure more robust and resistant to deformation, which helps to improve system stability and reduce manufacturing complexity and cost. In addition, the mounting base plate 21 is provided with several connecting holes 212, which are used to connect to the lens module of the projection equipment through fasteners. In this embodiment, the connecting holes can be screw holes, and the fasteners can be fastening screws.

[0033] The adjusting screw 3 is fitted with an adjusting block 4 on its outer periphery, and the adjusting block 4 can reciprocate along the adjusting screw 3; the mounting frame 2 includes a mounting base plate 21 and a front mounting plate 22 and a rear mounting plate 23 located on both sides of the base plate; one end of the adjusting screw 3 is connected to the center of the rear mounting plate 23, and the other end passes through the front mounting plate 22 and is drivenly connected to the stepper motor 1; specifically, the center of the front mounting plate 22 is provided with a through hole 221 for connecting with the adjusting screw 3, and the end of the adjusting screw 3 is installed in the through hole 221 by a bearing or a pad.

[0034] The adjustment block 4 is located between the front mounting plate 22 and the rear mounting plate 23 and moves back and forth along the adjustment screw 3; the end of the adjustment block 4 facing the mounting base plate 21 is provided with a limiting groove 41 that is connected to the cylindrical connector of the lens module, and the mounting base plate 21 is provided with an adjustment hole 211 corresponding to the limiting groove 41.

[0035] In this embodiment, the advantage of this design is that the adjusting block has a limiting groove structure, and the bottom of the adjusting block has a limiting groove structure. The structural dimensions of the limiting groove match the cylindrical connector on the projection device lens module. The user only needs to insert the cylindrical connector into the limiting groove to achieve a quick and reliable mechanical connection, which significantly improves assembly efficiency. At the same time, since the intermediate connector and redundant structure are eliminated, the whole machine is optimized in terms of material use, inventory management and manual operation, thereby effectively reducing the overall cost of the product in the design, production and after-sales stages, and improving the efficiency and consistency of mass production.

[0036] Optionally, the adjustment hole 211 is a strip-shaped adjustment hole 211 extending along the movement direction of the adjustment lever 4, and the length of the adjustment hole 211 matches the focusing stroke of the lens module. The strip-shaped adjustment hole provides a sliding path for the lever within the focusing stroke, which can limit the horizontal movement direction of the lever and play a role in lateral limiting and guiding; at the same time, it leaves sufficient stroke space for the lens module, improving the compatibility and adaptability of the module.

[0037] To further improve focusing accuracy and smoothness of movement, optionally, the mounting bracket 2 is provided with a guide rod 5, the two ends of which are connected to the front mounting plate 22 and the rear mounting plate 23 respectively; the adjusting block 4 is provided with a guide hole 42 that matches the guide rod 5, and is slidably connected to the guide rod 5 through the guide hole 42. The sliding fit between the guide rod and the guide hole further restricts the wobbling of the block in the non-axial direction, ensuring that the block moves smoothly and linearly along the screw axis.

[0038] The specific structure of the stepper motor is further described below:

[0039] The stepper motor 1 includes a front housing 11, a rear housing 12, and a stator assembly 13 and a rotor assembly 14 disposed between the front housing 11 and the rear housing 12. The rotor assembly 14 includes a columnar magnet 141 that is pulverizedly connected to the adjusting screw 3, and the magnet 141 is sleeved on the outer periphery of the adjusting screw 3. The stator assembly 13 includes a winding frame 131 sleeved on the outer periphery of the magnet 141 and a coil 132 wound on the outer periphery of the winding frame 131. When the coil 132 is energized, it drives the magnet 141 to rotate the adjusting screw 3.

[0040] In further detail, the winding frame 131 has winding portions 1311 at both ends for mounting the coil 132. The front housing 11 and the rear housing 12 are respectively provided with mounting grooves that engage with the winding portions 1311 at their ends facing the winding frame 131, and are respectively mounted at both ends of the winding frame 131 through the cooperation of the mounting grooves with the winding portions 1311. The outer side of the rear housing 12 is provided with a fixed bottom cover 15. The end of the adjusting screw 3 near the rear housing 12 is fitted with a bottom cover bearing 16.

[0041] This stepper motor achieves precise control through electromagnetic induction between a magnet and a wound coil. When the coil is energized according to a set current sequence, a periodically changing magnetic field is generated inside the coil frame. This magnetic field acts on the magnet nested within the coil, generating a rotational driving torque that causes the magnet to rotate around the central axis. Since the magnet and the adjusting screw are fixedly connected, the rotation of the magnet directly drives the adjusting screw, thus achieving linear forward and backward movement of the adjusting lever.

[0042] Optionally, a limiting spring 17 is provided between the fixed bottom cover 15 and the bottom cover bearing 16. The center of the limiting spring 17 is provided with a pressing spring 171 protruding towards the adjusting screw 3. The pressing spring 171 is fixed to the end of the adjusting screw 3 near the rear housing 12. The advantages of this design are: firstly, by using the pressing spring 171 to axially abut the end of the adjusting screw, precise positioning of the screw can be achieved, preventing axial movement during motor drive, thereby ensuring displacement accuracy and repeatability stability during focusing; secondly, the limiting spring structure has a certain elastic buffering capacity, which can absorb the small vibrations and impacts generated during the rotation of the adjusting screw, effectively reducing system operating noise.

[0043] It should be noted that this structure also includes other components for realizing the focusing function, including but not limited to circuit board assemblies, connecting cables for powering the system, power modules, interface devices for signal transmission, and standard fasteners required for installation and fixation. Since this invention focuses on the optimization and structural integration of the core transmission mechanism of the focusing structure, it does not redesign the aforementioned electrical connections and control modules; standard components from existing mature technologies can be used for implementation.

[0044] The above embodiments are merely preferred embodiments of the present utility model and should not be construed as limiting the scope of protection of the present utility model. For those skilled in the art, it will be understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present utility model. The scope of the present utility model is defined by the appended claims and their equivalents.

Claims

1. A focusing structure for use in a short-throw projection device, for connection to the lens module of the projection device, wherein the lens module is provided with a cylindrical connector; characterized in that, The system includes a coaxially mounted stepper motor and a mounting bracket. The stepper motor is connected to the mounting bracket via an adjusting screw. An adjusting block is fitted around the adjusting screw and can reciprocate along the adjusting screw. The mounting bracket includes a mounting base plate and a front mounting plate and a rear mounting plate located on both sides of the base plate. One end of the adjusting screw is connected to the center of the rear mounting plate, and the other end passes through the front mounting plate and is connected to the stepper motor. The adjusting block is located between the front and rear mounting plates and reciprocates along the adjusting screw. The end of the adjusting block facing the mounting base plate has a limiting groove that engages with a cylindrical connector of the lens module. The mounting base plate has an adjusting hole corresponding to the limiting groove.

2. The focusing structure applied to a short-throw projection device as described in claim 1, characterized in that, The adjustment hole is a strip-shaped adjustment hole extending along the direction of movement of the adjustment lever, and the length of the adjustment hole matches the focusing stroke of the lens module.

3. The focusing structure applied to a short-throw projection device as described in claim 2, characterized in that, The mounting bracket is provided with a guide rod, and the two ends of the guide rod are respectively connected to the front mounting plate and the rear mounting plate; the adjusting block is provided with a guide hole adapted to the guide rod, and is slidably connected to the guide rod through the guide hole.

4. The focusing structure for short-throw projection devices as described in claim 3, characterized in that, The stepper motor has a step angle of 9 degrees; the adjusting screw has a pitch of 0.2 mm.

5. The focusing structure for a short-throw projection device as described in claim 4, characterized in that, The stepper motor includes a front housing, a rear housing, and a stator assembly and a rotor assembly disposed between the front housing and the rear housing; the rotor assembly includes a columnar magnet sleeved on the outer periphery of the adjusting screw and driving the adjusting screw to rotate, the magnet being sleeved on the outer periphery of the adjusting screw; the stator assembly includes a winding frame sleeved on the outer periphery of the columnar magnet and a coil wound on the outer periphery of the winding frame; when the coil is energized, it drives the magnet to drive the adjusting screw to rotate.

6. The focusing structure for a short-throw projection device as described in claim 5, characterized in that, The winding frame has winding portions at both ends for mounting the coil. The front end housing and the rear end housing are respectively provided with mounting grooves that engage with the winding portions at their ends facing the winding frame, and are respectively mounted at both ends of the winding frame through the cooperation of the mounting grooves with the winding portions. The outer side of the rear end housing is provided with a fixed bottom cover. The end of the adjusting screw near the rear end housing is fitted with a bottom cover bearing.

7. The focusing structure for a short-throw projection device as described in claim 6, characterized in that, A limiting spring is provided between the fixed bottom cover and the bottom cover bearing. The center of the limiting spring is provided with a pressing spring that protrudes toward the adjusting screw. The pressing spring is fixed to the end of the adjusting screw near the rear housing.

8. The focusing structure for a short-throw projection device as described in claim 7, characterized in that, The mounting bracket is integrally bent from a metal plate, and the front mounting plate, rear mounting plate and mounting base plate have U-shaped or inverted C-shaped cross sections.

9. The focusing structure applied to a short-throw projection device as described in claim 1, characterized in that, The front mounting plate has a through hole at its center for connecting with the adjusting screw, and the end of the adjusting screw is mounted in the through hole by a bearing or a pad.

10. The focusing structure applied to a short-throw projection device as described in claim 1, characterized in that, The mounting base plate is provided with several connecting holes, which are used to connect to the lens module of the projection device through fasteners.

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