Auxiliary calibration device
By designing an auxiliary calibration device including a base and a slider, the problem of difficulty in calibration after the laser treatment instrument is solved, the rapid accuracy of laser calibration is achieved and the treatment efficiency is improved.
Patent Information
- Application Number
- CN202421088132.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-17
- Publication Date
- 2025-02-14
- Estimated Expiration
- 2034-05-17
AI Technical Summary
Existing laser therapy instruments need to be calibrated after changing hands. Currently, they mainly rely on human eye observation, which is prone to errors and cannot quickly and accurately determine whether the laser is in the center of the hand tool.
Design an auxiliary calibration device, including a base and a slider, with a placement position and calibration point on the top of the base. The slider is used to clamp the hand tools. By observing whether the laser exit point coincides with the calibration point, it quickly and accurately determines whether the laser is corrected. .
The rapid accuracy of laser calibration is achieved, artificial errors are reduced, and treatment efficiency is improved.
Smart Images
Figure CN222481787U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of laser treatment, in particular to an auxiliary calibration device. Background Art
[0002] Laser freckle removal, laser mole removal and laser hair removal are common cosmetic methods, usually performed with the aid of a therapeutic device. The therapeutic device includes a handle and a handpiece. A laser emitter is provided in the handle, and a lens is provided in the handpiece. The laser is emitted from the handle and focused by the lens to act on the treated skin. In order to make the laser have different spot sizes or different focusing depths, the handle is usually equipped with multiple types of handpieces, so that different lenses can be easily replaced. However, due to the cumulative tolerances of the various structures of the handle and the handpiece, it is very easy for the emitted laser to deviate from the center of the handpiece. Therefore, the laser needs to be calibrated after each handpiece is replaced. At present, laser calibration mainly relies on human eye observation to determine whether the laser is in the center of the handpiece, and such a calibration method is prone to errors. Utility Model Content
[0003] The main purpose of the utility model is to provide an auxiliary calibration device, by means of which it is possible to quickly and accurately determine whether the laser emitted from the treatment handle is in the center of the treatment handpiece.
[0004] To achieve the above-mentioned purpose, the auxiliary calibration device proposed in the utility model includes a base, the top surface of the base is provided with a plurality of placement positions for placing therapeutic hand tools, each of the placement positions is provided with sliders for clamping the therapeutic hand tools on both sides, and the base is provided with a calibration point at least at the center of each of the placement positions.
[0005] In one embodiment, the top surface of the base is provided with a first convex ring and a second convex ring which are arranged concentrically, the second convex ring is arranged around the first convex ring, a first placement position is formed between the first convex ring and the second convex ring, the inner side wall or the outer side wall of the first convex ring is used to fit and limit the shell of the first treatment handpiece, and the inner side wall or the outer side wall of the second convex ring is used to fit and limit the shell of the second treatment handpiece. The second convex ring is provided with a slide groove on two opposite sides, the slider is arranged in the slide groove, the slider has a first position and a second position, when the slider slides to the first position, the two sliders clamp the first treatment handpiece, and when the slider slides to the second position, the two sliders clamp the second treatment handpiece.
[0006] In one embodiment, the top surface of the base is provided with a groove, the first convex ring and the second convex ring are both arranged in the groove and are arranged concentrically with the groove, a second placement position is formed between the outer side wall of the second convex ring and the inner side wall of the groove, and the inner side wall of the groove is used to fit and limit the outer side wall of the third therapeutic handpiece. The slider also has a third position, and when the slider slides to the third position, the two sliders clamp the third therapeutic handpiece.
[0007] In one embodiment, the top surface of the base is provided with adjacent grooves of different sizes to form a placement position adapted for therapeutic handpieces of different sizes.
[0008] In one embodiment, the top surface of the base is provided with adjacent convex rings of different sizes to form a placement position adapted to therapeutic handpieces of different sizes.
[0009] In one embodiment, the auxiliary calibration device further includes a locking assembly, which is disposed between the slider and the base and is used to lock the slider.
[0010] In one embodiment, a connecting hole is provided on the slider, and a strip guide hole is provided on the base, the length direction of the guide hole is consistent with the sliding direction of the slider, the locking assembly includes a screw and a nut, the screw rod of the screw is passed through the connecting hole and the guide hole and at least partially extends out of the base, and the nut is screwed on the free end of the screw.
[0011] In one embodiment, a avoidance groove is recessed at the bottom of the base, and the avoidance groove is connected to the guide hole. The screw rod of the screw passes through the guide hole and extends into the avoidance groove. The width of the avoidance groove is greater than the width of the guide hole. The depth of the avoidance groove is not less than the extended length of the screw. The nut is sleeved on the screw rod of the screw and abuts against the bottom wall of the avoidance groove.
[0012] In one embodiment, limiting columns are provided on both sides of the therapeutic handpiece, and a clamping groove is recessed at one end of the sliding block facing the placement position, and the clamping groove is used to clamp the limiting column to prevent the therapeutic handpiece from rotating.
[0013] In one embodiment, a plurality of calibration points are arranged in the coverage area of the placement position, and the calibration points are arranged in an array with the center point of the placement position as the center.
[0014] The auxiliary calibration device includes a base, the top surface of the base is provided with a plurality of placement positions for placing the therapeutic handpiece, and sliders for clamping the therapeutic handpiece are provided on both sides of each placement position, and the base is provided with a calibration point at least at the center of each placement position. When in use, the therapeutic handle is docked with the corresponding therapeutic handpiece, and then the therapeutic handpiece is inverted on the placement position of the base to ensure that the center of the therapeutic handpiece coincides with the center of the placement position. At this time, it is only necessary to observe whether the laser emission point coincides with the calibration point at the center of the placement position to quickly and accurately determine whether the laser is calibrated. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.
[0016] Figure 1 An exploded view of an embodiment of an auxiliary calibration device provided by the utility model;
[0017] Figure 2 A schematic diagram of the assembly structure of an auxiliary calibration device according to the present invention;
[0018] Figure 3 A cross-sectional view of an embodiment of an auxiliary calibration device provided by the utility model;
[0019] Figure 4 A schematic diagram of assembling an auxiliary calibration device according to the present invention and a first therapeutic hand tool;
[0020] Figure 5 A schematic diagram of assembling an auxiliary calibration device according to an embodiment of the present invention and a second therapeutic hand tool;
[0021] Figure 6 This is a schematic diagram of assembling an auxiliary calibration device according to an embodiment of the present invention and a third therapeutic hand tool.
[0022] Description of Figure Numbers:
[0023] 100. Auxiliary calibration device; 1. Base; 11. First convex ring; 12. Second convex ring; 13. Slide groove; 14. Groove; 15. Guide hole; 16. Avoidance groove; 17. Calibration point; 2. Slider; 21. Connecting hole; 22. Slot; 3. Screw; 4. Nut; 600. Treatment handpiece; 6. Limit column.
[0024] The realization of the purpose, functional features and advantages of the utility model will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION
[0025] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.
[0026] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back...), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indications will also change accordingly.
[0027] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the utility model, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of the features. In addition, if "and / or" or "and / or" appears in the full text, its meaning includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or solutions that satisfy both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the utility model.
[0028] Laser freckle removal, laser mole removal and laser hair removal are common cosmetic methods, usually performed with the aid of a therapeutic device. The therapeutic device includes a handle and a handpiece. A laser emitter is provided in the handle, and a lens is provided in the handpiece. The laser is emitted from the handle and focused by the lens to act on the treated skin. In order to make the laser have different spot sizes or different focusing depths, the handle is usually equipped with multiple types of handpieces, so that different lenses can be easily replaced. However, due to the cumulative tolerances of the various structures of the handle and the handpiece, it is very easy for the emitted laser to deviate from the center of the handpiece. Therefore, the laser needs to be calibrated after each handpiece is replaced. At present, laser calibration mainly relies on human eye observation to determine whether the laser is in the center of the handpiece, and such a calibration method is prone to errors.
[0029] To this end, the present invention proposes an auxiliary calibration device 100 , by means of which it is possible to quickly and accurately determine whether the laser emitted from the treatment handle is at the center of the treatment handpiece 600 .
[0030] See also Figures 1 to 6 An embodiment of the auxiliary calibration device 100 includes a base 1, the top surface of the base 1 is provided with a plurality of placement positions for placing the therapeutic handpiece 600, and sliders 2 for clamping the therapeutic handpiece 600 are provided on both sides of each placement position. The base 1 is provided with a calibration point 17 at least at the center of each placement position.
[0031] In the auxiliary calibration device 100 , the top surface of the base 1 may be provided with a groove 14 or a convex ring to form a plurality of placement positions of different sizes, so as to adapt to the calibration requirements of therapeutic handpieces 600 of different sizes.
[0032] For example, in one embodiment, the top surface of the base 1 is provided with a first convex ring and a second convex ring which are arranged concentrically, and the second convex ring is arranged around the first convex ring, that is, the second convex ring is arranged on the outer ring of the first convex ring, and a first placement position is formed between the first convex ring and the second convex ring. The size of the first convex ring matches the size of the first therapeutic handpiece 600, and the size of the second convex ring matches the size of the second therapeutic handpiece 600. The inner side wall or the outer side wall of the first convex ring is used to fit and limit the shell of the first therapeutic handpiece 600, and the inner side wall or the outer side wall of the second convex ring is used to fit and limit the shell of the second therapeutic handpiece 600. The second convex ring is provided with a slide groove 13 on two opposite sides, and a notch is provided on two opposite sides of the second convex ring to connect the slide groove 13. The slider 2 is provided in the slide groove 13, and the slider 2 has a first position and a second position. When the slider 2 slides to the first position, the two sliders 2 clamp the first therapeutic handpiece 600, and when the slider 2 slides to the second position, the two sliders 2 clamp the second therapeutic handpiece 600.
[0033] The first convex ring and the second convex ring are designed according to the sizes of the equipped first treatment handpiece 600 and the second treatment handpiece 600, and the treatment handpiece 600 is opened at one end facing the base 1, so that the first convex ring or the second convex ring can be inserted into the opening of the treatment handpiece 600 to fit and limit the inner wall of the treatment handpiece 600. When the inner diameter of the first convex ring is consistent with the outer diameter of the shell of the first treatment handpiece 600, the inner wall of the first convex ring can fit and limit the outer wall of the first treatment handpiece 600; similarly, when the inner diameter of the second convex ring is consistent with the outer diameter of the shell of the second treatment handpiece 600, the inner wall of the second convex ring can fit and limit the outer wall of the second treatment handpiece 600. In this embodiment, the first convex ring and the second convex ring are concentrically arranged, the center points of the first convex ring and the second convex ring coincide, and the base 1 is provided with a calibration point 17 at the center of the convex ring. When in use, the treatment handle is docked with the corresponding treatment handpiece 600, and then the treatment handpiece 600 is turned upside down on the base 1, so that the treatment handpiece 600 and the first convex ring or the second convex ring are fitted and limited to ensure that the treatment handpiece 600 and the first convex ring or the second convex ring are concentric. At this time, it is only necessary to observe whether the laser emission point coincides with the calibration point 17 at the center of the convex ring to quickly and accurately determine whether the laser is calibrated.
[0034] Furthermore, a groove 14 is concavely provided on the top surface of the base 1, and the cross-sectional dimension of the groove 14 is larger than the cross-sectional dimension of the second convex ring. The first convex ring and the second convex ring are both arranged in the groove 14 and are arranged concentrically with the groove 14. A second placement position is formed between the outer side wall of the second convex ring and the inner side wall of the groove 14. The inner side wall of the groove 14 is used to fit and limit the outer side wall of the third therapeutic hand tool 600. At this time, the slider 2 has a first position, a second position and a third position. When the slider 2 slides to the first position, the two sliders 2 clamp the first therapeutic hand tool 600. When the slider 2 slides to the second position, the two sliders 2 clamp the second therapeutic hand tool 600. When the slider 2 slides to the third position, the two sliders 2 clamp the third therapeutic hand tool 600.
[0035] In this embodiment, the first convex ring and the second convex ring are arranged in the groove 14, so that a second placement position is formed between the outer side wall of the second convex ring and the inner side wall of the groove 14, so that more therapeutic hand tools 600 can be adapted. It is not difficult to understand that the more concentric convex rings are arranged in the groove 14, the more therapeutic hand tools 600 can be adapted, and the utility model does not limit the number of convex rings.
[0036] The above embodiment sets multiple placement positions concentrically, which can save the area occupied by multiple placement positions and thus reduce the volume of the base 1. On the other hand, only one pair of sliders 2 is needed to clamp multiple treatment handpieces 600 at the same time, reducing the number of sliders 2.
[0037] In another embodiment, the top surface of the base 1 is provided with adjacent grooves 14 of different sizes to form a placement position for the treatment handpiece 600 of different sizes. For example, the top surface of the base 1 is provided with adjacent first grooves and second grooves of different sizes, the diameter of the first groove is consistent with the outer diameter of the first treatment handpiece 600, the diameter of the second groove is consistent with the outer diameter of the second treatment handpiece 600, the first groove forms a first placement position, the inner side wall of the first groove is used to fit and limit with the outer side wall of the first treatment handpiece 600, the second groove forms a second placement position, the inner side wall of the second groove is used to fit and limit with the outer side wall of the second treatment handpiece 600. At this time, two oppositely arranged first slide grooves 13 are provided on both sides of the first groove, a first slider 2 is provided in the first slide groove 13, and the two first sliders 2 are used to clamp the first treatment handpiece 600, and two oppositely arranged second slide grooves 13 are provided on both sides of the second groove, a second slider 2 is provided in the second slide groove 13, and the two second sliders 2 are used to clamp the second treatment handpiece 600. At this time, the base 1 is provided with a first calibration point 17 at the center of the first groove, and a second calibration point 17 at the center of the second groove. When calibrating the first therapeutic handpiece 600, the first therapeutic handpiece 600 is turned upside down in the first groove, and then it is observed whether the laser emission point of the first therapeutic handpiece 600 coincides with the first calibration point 17, so that it can be quickly and accurately determined whether the laser emitted from the first therapeutic handpiece 600 is corrected; when calibrating the second therapeutic handpiece 600, the second therapeutic handpiece 600 is turned upside down in the second groove, and then it is observed whether the laser emission point of the second therapeutic handpiece 600 coincides with the second calibration point 17, so that it can be quickly and accurately determined whether the laser emitted from the second therapeutic handpiece 600 is corrected.
[0038] In another embodiment, the top surface of the base 1 is provided with adjacent convex rings of different sizes to form a placement position for treatment hand tools 600 of different sizes. For example, the top surface of the base 1 is provided with adjacent first convex rings and second convex rings of different sizes, the first convex ring forms a first placement position, the inner side wall or outer side wall of the first convex ring is used to fit and limit with the shell of the first treatment hand tool 600, the second convex ring forms a second placement position, the inner side wall or outer side wall of the second convex ring is used to fit and limit with the shell of the second treatment hand tool 600. At this time, two oppositely arranged first slide grooves 13 are provided on both sides of the first convex ring, the first slide block 2 is provided in the first slide groove 13, and the two first slide blocks 2 are used to clamp the first treatment hand tool 600. Two oppositely arranged second slide grooves 13 are provided on both sides of the second convex ring, the second slide block 2 is provided in the second slide groove 13, and the two second slide blocks 2 are used to clamp the second treatment hand tool 600. At this time, the base 1 is provided with a first calibration point 17 at the center of the first convex ring, and a second calibration point 17 at the center of the second convex ring. When calibrating the first therapeutic handpiece 600, the first therapeutic handpiece 600 is turned upside down to match the first convex ring, and then the laser emission point of the first therapeutic handpiece 600 is observed to coincide with the first calibration point 17, so that it can be quickly and accurately determined whether the laser emitted from the first therapeutic handpiece 600 is corrected; when calibrating the second therapeutic handpiece 600, the second therapeutic handpiece 600 is turned upside down to match the second convex ring, and then the laser emission point of the second therapeutic handpiece 600 is observed to coincide with the second calibration point 17, so that it can be quickly and accurately determined whether the laser emitted from the second therapeutic handpiece 600 is corrected.
[0039] In summary, the auxiliary calibration device 100 includes a base 1, the top surface of the base 1 is provided with a plurality of placement positions for placing the therapeutic handpiece 600, and sliders 2 for clamping the therapeutic handpiece 600 are provided on both sides of each placement position, and the base 1 is provided with a calibration point 17 at least at the center of each placement position. When in use, the therapeutic handle is docked with the corresponding therapeutic handpiece 600, and then the therapeutic handpiece 600 is inverted on the placement position of the base 1 to ensure that the center of the therapeutic handpiece 600 coincides with the center of the placement position. At this time, it is only necessary to observe whether the laser emission point coincides with the calibration point 17 at the center of the placement position to quickly and accurately determine whether the laser is calibrated.
[0040] The embodiment of the auxiliary calibration device 100 further includes a locking component, which is disposed between the slider 2 and the base 1 and is used to lock the slider 2 .
[0041] In the embodiment shown in the figure, a connecting hole 21 is provided on the slider 2, and a strip-shaped guide hole 15 is provided on the base 1. The length direction of the guide hole 15 is consistent with the sliding direction of the slider 2. The locking assembly includes a screw 3 and a nut 4. The screw rod of the screw 3 is inserted into the connecting hole 21 and the guide hole 15 and at least partially extends out of the base 1. The nut 4 is screwed on the free end of the screw 3. Therefore, screwing the nut 4 to a loose state can release the slider 2 to facilitate the free sliding of the slider 2. The nut 4 and the screw slide together with the slider 2. When the slider 2 slides to a desired position, the nut 4 is screwed to a locked state to lock the slider 2, thereby realizing the rapid adjustment of the position of the slider 2.
[0042] At the same time, an avoidance groove 16 is recessed at the bottom of the base 1, and the avoidance groove 16 is connected to the guide hole 15. The screw rod of the screw 3 passes through the guide hole 15 and extends into the avoidance groove 16. The width of the avoidance groove 16 is greater than the width of the guide hole 15, and the depth of the avoidance groove 16 is not less than the extended length of the screw 3. The nut 4 is sleeved on the screw rod of the screw 3 and abuts against the bottom wall of the avoidance groove 16 to lock the slider 2.
[0043] The therapeutic handpiece 600 is hollowed out, and limiting posts 6 are arranged on both sides of the therapeutic handpiece 600. A clamping groove 22 is recessed at one end of the slider 2 facing the placement position, and the clamping groove 22 is used to clamp the limiting post 6 to prevent the therapeutic handpiece 600 from rotating.
[0044] In an embodiment of the present invention, a plurality of calibration points 17 are arranged in the coverage area of the placement position, and the calibration points 17 are arranged in an array with the center point of the placement position as the center.
[0045] In the actual treatment process, in order to allow the emitted laser to cover a larger treatment area and reduce the number of times the therapeutic device moves, the emitted laser is usually set with a movement trajectory. In order to detect whether the emitted laser moves according to the preset trajectory, this embodiment sets a plurality of calibration points 17 in the coverage area of the placement position, and the plurality of calibration points 17 are arranged in an array with the center point of the placement position as the center. During calibration, the laser transmitter is started to run a stroke. During this process, it is observed whether the laser emission point passes through the corresponding calibration point 17. If the moving light of the laser passes through the specified calibration points 17 in sequence, it means that the emitted laser is running strictly according to the required trajectory. If the moving light of the laser deviates from the specified one or more calibration points 17, it means that the emitted laser is not accurate enough and needs to be corrected. Therefore, this embodiment can not only quickly determine whether the initial laser is located at the center of the therapeutic handpiece 600, but also quickly determine whether the running trajectory of the laser meets the set requirements.
[0046] The above description is only an exemplary embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the technical concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.
Claims
1. An auxiliary calibration device, characterized in that: The base comprises a base, wherein the top surface of the base is provided with a plurality of placement positions for placing the therapeutic hand tool, and sliders for clamping the therapeutic hand tool are provided on both sides of each placement position, and the base is provided with a calibration point at least at the center of each placement position; The top surface of the base is convexly provided with a first convex ring and a second convex ring which are arranged concentrically, the second convex ring is arranged around the first convex ring, a first placement position is formed between the first convex ring and the second convex ring, the inner side wall or the outer side wall of the first convex ring is used to fit and limit the position with the shell of the first treatment handpiece, and the inner side wall or the outer side wall of the second convex ring is used to fit and limit the position with the shell of the second treatment handpiece; The second convex ring is provided with slide grooves on opposite sides, the slider is provided in the slide groove, the slider has a first position and a second position, when the slider slides to the first position, the two sliders clamp the first treatment handpiece, when the slider slides to the second position, the two sliders clamp the second treatment handpiece.
2. The auxiliary calibration device according to claim 1, characterized in that: A groove is concavely formed on the top surface of the base, the first convex ring and the second convex ring are both arranged in the groove and are arranged concentrically with the groove, a second placement position is formed between the outer side wall of the second convex ring and the inner side wall of the groove, and the inner side wall of the groove is used to fit and limit the outer side wall of the third therapeutic handpiece; The slide block also has a third position. When the slide block slides to the third position, the two slide blocks clamp the third treatment handpiece.
3. The auxiliary calibration device according to claim 1, characterized in that: The top surface of the base is concavely provided with adjacent grooves of different sizes to form a placement position adapted to therapeutic hand tools of different sizes.
4. The auxiliary calibration device according to claim 1, characterized in that: The top surface of the base is convexly provided with adjacent convex rings of different sizes to form a placement position adapted to therapeutic hand tools of different sizes.
5. The auxiliary calibration device according to claim 1, characterized in that: The auxiliary calibration device also includes a locking component, which is arranged between the slider and the base and is used to lock the slider.
6. The auxiliary calibration device according to claim 5, characterized in that: The slider is provided with a connecting hole, and the base is provided with a strip guide hole, the length direction of the guide hole is consistent with the sliding direction of the slider, the locking assembly includes a screw and a nut, the screw rod of the screw is passed through the connecting hole and the guide hole and at least partially extends out of the base, and the nut is screwed on the free end of the screw.
7. The auxiliary calibration device according to claim 6, characterized in that: An avoidance groove is recessed at the bottom of the base, and the avoidance groove is connected to the guide hole. The screw rod of the screw passes through the guide hole and extends into the avoidance groove. The width of the avoidance groove is greater than the width of the guide hole. The depth of the avoidance groove is not less than the extended length of the screw. The nut is sleeved on the screw rod of the screw and abuts against the bottom wall of the avoidance groove.
8. The auxiliary calibration device according to claim 1, characterized in that: Limiting columns are arranged on both sides of the therapeutic handpiece, and a clamping groove is recessed at one end of the sliding block facing the placement position, and the clamping groove is used to clamp the limiting column to prevent the therapeutic handpiece from rotating.
9. The auxiliary calibration device according to claim 1, characterized in that: A plurality of calibration points are arranged in the coverage area of the placement position, and the calibration points are arranged in an array with the center point of the placement position as the center.