Visual training instrument
By integrating a display module, massage bumps, and conductive components, the vision training device solves the problem of limited functionality in existing vision training devices, enabling multi-faceted vision recovery training and improving the effectiveness of vision training.
Patent Information
- Application Number
- CN202422717405.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-07
- Publication Date
- 2025-10-31
- Estimated Expiration
- 2034-11-07
AI Technical Summary
Existing vision training devices have limited functions, and their vision training effects are insufficient to meet user needs.
Design a vision training device that integrates a display module, massage protrusions, and conductive components. Vision training is conducted by observing images, and combined with massage and monitoring of eye muscle biocurrents, it achieves multi-faceted vision recovery training.
It enhances the effectiveness of vision training by combining multiple functions, thereby improving the results and user experience.
Smart Images
Figure CN223490048U_ABST
Abstract
Description
Technical Field
[0001] This application belongs to the technical field of vision improvement equipment, specifically relating to a vision training device. Background Technology
[0002] Vision training, also known as vision recovery training, aims to improve uncorrected visual acuity and overall visual health. It involves scientific physical exercises and training of the eyes and visual system to enhance the eye's accommodative ability, helping to prevent myopia and correct amblyopia, and ultimately improving uncorrected visual acuity. Vision training devices are instruments specifically designed for vision training. However, currently available vision training devices have limited functionality, and their effectiveness often fails to meet user needs. Utility Model Content
[0003] The purpose of this application is to provide a vision training device that addresses the technical problem that existing vision training devices have limited functionality and fail to meet user needs in terms of vision training effectiveness.
[0004] To achieve the above objectives, the technical solution adopted in this application is: a vision training device, including a shell, a display module and functional components. A window is provided on one side of the shell, the display module is disposed inside the shell and corresponds to the window, and the functional components are disposed on the side of the shell with the window. The functional components include massage protrusions and conductive elements, and the conductive elements are capable of collecting biocurrents from the eye muscles.
[0005] Furthermore, massage protrusions are provided on the outer casing, and conductive components are provided on the massage protrusions.
[0006] Furthermore, the massage protrusion includes a package and a vibration component disposed within the package. One end of the package is connected to the outer shell, and the end of the package away from the outer shell is provided with a through hole. The conductive component includes an internal part and an external part. One side of the internal part abuts against the vibration component, and the other side of the internal part abuts against the inner wall of the package. The external part is connected to the internal part and extends out of the package through the through hole.
[0007] Furthermore, the massage protrusion includes an encapsulation body and a vibration component, the encapsulation body being connected to the housing, and the vibration component being disposed within the encapsulation body.
[0008] Furthermore, the package and the outer shell are integrated into one unit.
[0009] Furthermore, the vision training device also includes a distance sensor, which is located on the side of the housing with a window or inside the housing and corresponds to the window.
[0010] Furthermore, there are multiple functional components, which are arranged around the viewport.
[0011] Furthermore, the vision training device also includes a circuit board and a battery, both of which are housed within the casing. The battery, display module, and conductive components are all electrically connected to the circuit board.
[0012] Furthermore, the vision training device also includes an optical component, which is housed within the casing and located between the display module and the viewing window. Light emitted from the display module passes through the optical component and shines onto the viewing window.
[0013] Furthermore, the vision training device also includes an elastic band, with both ends of the elastic band connected to the outer shell.
[0014] Compared with existing technologies, the beneficial effects of the vision training device provided in this application are as follows: During use, the user aligns their eyes with the viewing window on the casing and brings the functional components into contact with the area around the eyes. On the one hand, the user can train their vision by observing the images displayed on the module; on the other hand, the massage protrusions in the functional components can massage the eye muscles, and the conductive components can collect bio-currents from the eye muscles to monitor the eye condition. The vision training device provided in this application, by integrating multiple functions, provides vision recovery training from different aspects, thereby achieving the goal of enhancing the effectiveness of vision training. Attached Figure Description
[0015] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0016] Figure 1 A front view of the vision training device provided in the embodiments of this application;
[0017] Figure 2 An exploded view of the vision training device provided in the embodiments of this application;
[0018] Figure 3 for Figure 2 A three-dimensional structural diagram of the functional components of the vision training device shown;
[0019] Figure 4 for Figure 2 A cross-sectional view of the functional components of the vision training device shown;
[0020] Figure 5 for Figure 4 A cross-sectional view of the conductive parts of the functional component shown.
[0021] Figure 6 for Figure 2 An exploded view of the functional components of the vision training device shown.
[0022] The following are the labeling elements in the figure:
[0023] 10. Outer shell; 11. Front shell; 111. Viewport; 12. Middle frame; 121. Connecting lug; 13. Bottom shell;
[0024] 20. Display module;
[0025] 30. Functional component; 31. Massage protrusion; 311. Encapsulation body; 3111. Through hole; 3112. First notch; 3113. Second notch; 312. Vibration component; 3121. Magnet; 3122. Rotor; 3123. Fixing frame; 3124. Circuit board; 3125. Brush; 313. Insulating inner shell; 3131. Flange; 314. Electrical connection component; 32. Conductive component; 321. Internal part; 3211. Positioning groove; 3212. Limiting protrusion; 3213. Limiting space; 322. External part;
[0026] 40. Distance sensor;
[0027] 50. Circuit board;
[0028] 60. Battery;
[0029] 70. Optical components;
[0030] 80. Elastic band. Detailed Implementation
[0031] The embodiments of this application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.
[0032] In the description of this application, it should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.
[0033] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.
[0034] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.
[0035] Combination Figure 1 and Figure 2 This application provides a vision training device, including a housing 10, a display module 20, and a functional component 30. A window 111 is provided on one side of the housing 10. The display module 20 is disposed inside the housing 10 and corresponds to the window 111. The functional component 30 is disposed on the side of the housing 10 where the window 111 is provided. The functional component 30 includes a massage protrusion 31 and a conductive element 32. The conductive element 32 can collect biocurrents from the eye muscles.
[0036] In use, the user aligns their eyes with the viewing window 111 of the outer casing 10 and brings the functional component 30 into contact with the area around the eyes. On one hand, the user can train their vision by observing the images displayed on the display module 20. On the other hand, the massage protrusions 31 in the functional component 30 can massage the eye muscles, and the conductive element 32 in the functional component 30 can collect bio-currents from the eye muscles to monitor the eye condition. The vision training device provided in this application, by integrating multiple functions, provides vision recovery training from different aspects, thereby achieving the purpose of enhancing the vision training effect.
[0037] Specifically, the display module 20 can be used for near and far vision training, eye-tracking training, and visual relaxation scenario simulation, which can train and regulate eye muscles, enhance eye accommodation ability, and relieve eye and brain fatigue. For example, the display module 20 can display a moving cursor, and the user's gaze can follow the cursor's movement, which can train eye muscles and thus improve vision. Furthermore, the display module 20 can be combined with AR or VR technology, allowing users to engage in fun and beneficial eye training in a 3D environment, thereby improving vision. Using the massage protrusions 31 to press and stimulate acupoints around the eyes can effectively relax eye muscles, promote blood circulation, and relieve eye fatigue. Using the conductive component 32 to collect the bio-current of the eye muscles, combined with software algorithms, it can detect eye movement, eye muscle fatigue levels, and whether the user follows the prompts of the display module 20 to complete the corresponding training plan in real time during eye training. It can also provide feedback on the eye muscle relaxation effect after the user completes the training, presenting a time curve to the user through the display module 20, thus visualizing the training effect. The system can determine whether to use the display module 20 for vision training by detecting the degree of eye muscle fatigue. When the conductive element 32 detects that eye fatigue has reached a certain level and training through the display module 20 is not suitable, the display module 20 can be temporarily suspended. Instead, the massage protrusions 31 can be used to press and massage the eyes to relieve eye fatigue and prevent damage from continued training under excessive fatigue. In another embodiment, in addition to collecting biocurrents from the eye muscles, the conductive element 32 can also release stimulating currents. Specifically, the stimulating current released by the conductive element 32 can be a mid-frequency pulse, which can effectively relax eye muscles, promote blood circulation in and around the eyes, and relieve eye fatigue.
[0038] In one embodiment, such as Figure 1 As shown, the massage protrusion 31 is disposed on the outer casing 10, and the conductive element 32 is disposed on the massage protrusion 31. Compared to separately disposing of the massage protrusion 31 and the conductive element 32 at different locations on the outer casing 10, by disposing of the conductive element 32 on the massage protrusion 31, no additional space is required in the outer casing 10, making manufacturing simpler and reducing the overall size of the product. Furthermore, with the massage protrusion 31 and the conductive element 32 located in the same position, targeted pressure stimulation and electrical stimulation can be applied to the same acupoint around the eye simultaneously, thereby enhancing the vision training effect. It should be noted that the conductive element 32 can be embedded inside the massage protrusion 31, disposed on the outer surface of the massage protrusion 31, or partially embedded inside the massage protrusion 31 with a portion located on the outside.
[0039] In one embodiment, such as Figure 3As shown, the massage protrusion 31 includes an encapsulation body 311 and a vibration component 312. The encapsulation body 311 is connected to the outer shell 10, and the vibration component 312 is disposed within the encapsulation body 311. On the one hand, the massage protrusion 31 can press and stimulate the eye muscles through the encapsulation body 311. On the other hand, the vibration component 312 can generate vibrations and transmit the vibration to the encapsulation body 311, and then to the eyes, thereby achieving vibration massage. This can effectively relax the eye muscles, promote blood circulation, relieve eye fatigue, and thus enhance the effect of vision training.
[0040] In one embodiment, the package 311 is integrally formed with the outer shell 10. This integral formation ensures reliable connection between the package 311 and the outer shell 10, preventing the package 311 from detaching from the outer shell 10 due to vibration. Specifically, the outer shell 10 can be made of rigid plastic, while the package 311 can be made of soft silicone. The package 311 and the outer shell 10 are integrally formed through a secondary injection molding process.
[0041] In one embodiment, combined Figure 3 and Figure 4 As shown, the end of the package 311 away from the outer shell 10 is provided with a through hole 3111. The conductive element 32 includes an internal part 321 and an external part 322. One side of the internal part 321 abuts against the vibration component 312, and the other side of the internal part 321 abuts against the inner wall of the package 311. The external part 322 is connected to the internal part 321 and extends out of the package 311 through the through hole 3111. By dividing the conductive element 32 into an internal part 321 and an external part 322, and placing the internal part 321 outside the package 311, with its opposite sides abutting against the vibration component 312 and the inner wall of the package 311 respectively, the conductive element 32 can be fixed, preventing it from coming out of the package 311 through the through hole 3111. The external part 322 extends out of the package 311 through the through hole 3111, thus satisfying the requirement of contact with the eye to release a stimulating current. It should be noted that the external dimensions of the built-in part 321 are larger than those of the through hole 3111, so that the built-in part 321 can abut against the inner wall of the package body 311 and the area around the through hole 3111, thereby preventing the conductive part 32 from coming out of the package body 311 through the through hole 3111.
[0042] In one embodiment, such as Figure 4As shown, the massage protrusion 31 also includes an insulating inner shell 313, which is disposed inside the package 311 and contacts the inner wall of the package 311. The vibration component 312 is disposed inside the insulating inner shell 313 and contacts the inner wall of the insulating inner shell 313. One side of the built-in portion 321 of the conductive component 32 abuts against the outer wall of the insulating inner shell 313, and the other side of the built-in portion 321 abuts against the inner wall of the package 311. It should be noted that, in this embodiment, the built-in portion 321 abuts against the vibration component 312 via an insulating inner shell 313. By providing an insulating inner shell 313 inside the package 311, the built-in portion 321 of the conductive component 32 abuts against the outer wall of the insulating inner shell 313 and the inner wall of the package 311, thereby fixing the conductive component 32. By placing the vibration component 312 inside the insulating inner shell 313, separately from the conductive component 32, direct contact between the vibration component 312 and the conductive component 32 can be avoided, thus preventing interference with normal operation. During operation, the vibration component 312 transmits vibration to the insulating inner shell 313, then to the package 311 and the conductive component 32, and finally to the eye. The insulating inner shell 313 can be made of silicone.
[0043] In one embodiment, combined Figure 4 and Figure 5 As shown, the built-in part 321 has a positioning groove 3211 on the side facing away from the external part 322. A limiting protrusion 3212 is provided on the side wall of the positioning groove 3211. A limiting space 3213 is formed between the limiting protrusion 3212 and the bottom wall of the positioning groove 3211. The insulating inner shell 313 is partially inserted into the positioning groove 3211. A flange 3131 is provided on the outer periphery of the part of the insulating inner shell 313 inserted into the positioning groove 3211. The flange 3131 is embedded in the limiting space 3213. First, by setting a positioning groove 3211 in the built-in part 321, the insulating inner shell 313 is partially inserted into the positioning groove 3211, which facilitates installation and provides circumferential limiting for the conductive component 32. Second, by setting a limiting protrusion 3212 on the side wall of the positioning groove 3211 and a flange 3131 on the outer periphery of the insulating inner shell 313, the flange 3131 is embedded in the limiting space 3213 between the limiting protrusion 3212 and the bottom wall of the positioning groove 3211, thereby providing axial limiting for the conductive component 32. Specifically, the limiting protrusion 3212 is annular, and the limiting space 3213 formed between it and the bottom wall of the positioning groove 3211 is also annular. The flange 3131 is correspondingly annular, which enhances the limiting effect on the conductive component 32.
[0044] In one embodiment, such as Figure 3As shown, the massage protrusion 31 also includes an electrical connection assembly 314, which includes a first electrical connector and a second electrical connector. One end of the first electrical connector is connected to the vibration assembly 312, and the other end is used to connect to a power source. One end of the second electrical connector is connected to the conductive element 32, and the other end is also used to connect to a power source. During operation, the first and second electrical connectors are connected to the power source. The current supplied by the power source can be transmitted to the vibration assembly 312 through the first electrical connector, causing the vibration assembly 312 to vibrate. The current supplied by the power source can also be transmitted to the conductive element 32 through the second electrical connector, thereby releasing a stimulating current. The first and second electrical connectors can be cables or circuits fabricated on the flexible circuit board 50.
[0045] In one embodiment, combined Figure 4 and Figure 6 As shown, the end of the package 311 away from the through hole 3111 is provided with a first notch 3112 and a second notch 3113. Both the first notch 3112 and the second notch 3113 are connected to the interior of the package 311. The second notch 3113 extends to the end of the package 311 with the through hole 3111. The electrical connection component 314 passes through the first notch 3112 and extends into the interior of the package 311 to connect with the vibration component 312. Partially, the electrical connection component 314 extends along the second notch 3113 to the end of the package 311 with the through hole 3111 and connects with the conductive component 32. Specifically, the first electrical connector and the second electrical connector in the electrical connection component 314 both extend into the interior of the package 311 from the first notch 3112. The first electrical connector is connected to the vibration component 312, and the second electrical connector continues to extend along the second notch 3113 to the end of the package 311 with the through hole 3111 and connects with the conductive component 32. By providing a first notch 3112 and a second notch 3113 on the package 311, the first and second electrical connectors can be positioned. The second electrical connector is embedded in the second notch 3113 without protruding from the outer wall of the package 311, making the massage protrusion 31 look neater and more aesthetically pleasing. In addition, the second electrical connector is located outside the insulating inner shell 313 and does not contact the vibration component 312, thus avoiding any impact on the operation of the vibration component 312.
[0046] In one embodiment, combined Figure 4 and Figure 6As shown, the vibration assembly 312 includes a magnet 3121, a rotor 3122, a mounting frame 3123, a circuit board 3124, and brushes 3125. The rotor 3122 is mounted on the mounting frame 3123 and passes through the interior of the magnet 3121. The brushes 3125 are disposed on the circuit board 3124. The rotor 3122 is electrically connected to the circuit board 3124 through the brushes 3125. The circuit board 3124 is connected to a first electrical connector. During operation, the power supply provides power to the circuit board 3124 through the first electrical connector. The circuit board 3124 is electrically connected to the rotor 3122 through the brushes 3125, driving the rotor 3122 to rotate inside the magnet 3121, thereby generating vibration.
[0047] In one embodiment, such as Figure 1 As shown, there are multiple functional components 30 arranged around the viewing window 111. By setting multiple functional components 30 and arranging them around the viewing window 111, it is possible to simultaneously massage multiple acupoints around the eyes and collect bio-currents from the eye muscles, which is beneficial for enhancing the vision training effect. In another embodiment, the conductive element 32 in the functional component 30, in addition to collecting bio-currents from the eye muscles, can also release stimulating currents, which can effectively relax the eye muscles, promote blood circulation in and around the eyes, and relieve eye fatigue.
[0048] In one embodiment, combined Figure 1 and Figure 2 As shown, the vision training device also includes a distance sensor 40. The distance sensor 40 is disposed on the side of the housing 10 where the viewing window 111 is located, or disposed inside the housing 10 and corresponding to the viewing window 111. The distance sensor 40 can be used to detect whether the user is wearing the vision training device correctly, and can also cooperate with the display module 20 to adjust the image displayed by the display module 20 according to the detection result of the distance sensor 40 to adapt to different users. Specifically, the distance sensor 40 can be an infrared distance sensor 40, and can be set to correspond to the user's forehead.
[0049] In one embodiment, combined Figure 1 and Figure 2As shown, the vision training device also includes a circuit board 50 and a battery 60, both housed within the outer casing 10. The battery 60, display module 20, and conductive component 32 are all electrically connected to the circuit board 50. During operation, the battery 60 powers the circuit board 50, display module 20, and conductive component 32. Furthermore, the biocurrents of the eye muscles collected by the conductive component 32 are fed back to the circuit board 50, which then controls the display module 20 based on the feedback, facilitating adjustments to the training plan. Specifically, the circuit board 50 is connected to the conductive component 32 via a second electrical connector, and to the vibration component 312 via a first electrical connector. During use, the battery 60 inside the outer casing 10 powers the circuit board 50, display module 20, conductive component 32, and vibration component 312, eliminating the need for constant external power connections and allowing for use anytime, anywhere, without spatial limitations.
[0050] In one embodiment, such as Figure 2 As shown, the vision training device also includes an optical component 70, which is disposed within the housing 10 and located between the display module 20 and the viewing window 111. Light emitted from the display module 20 passes through the optical component 70 and reaches the viewing window 111. The optical component 70, positioned between the display module 20 and the viewing window 111, can control and adjust the light emitted from the display module 20 to the viewing window 111, allowing the user to clearly see the display module 20 at a distance of less than 10cm from their eyes. The optical component 70 has a diopter adjustment function with an adjustment range of 0-500 degrees, and can be adjusted manually or automatically to meet the needs of different users.
[0051] In one embodiment, such as Figure 2 As shown, there are two display modules 20, one for the left eye and one for the right eye. By setting up two display modules 20, each corresponding to the left and right eyes respectively, and by independently controlling the two display modules 20 by the circuit board 50, training plans can be formulated separately for the left and right eyes, which is beneficial for correcting inconsistencies in vision between the left and right eyes.
[0052] In one embodiment, such as Figure 2 As shown, the vision training device also includes an elastic band 80, with both ends of the elastic band 80 connected to the outer casing 10. The vision training device can be worn on the user's head via the elastic band 80, freeing the user's hands and improving the user experience. The tightness of the elastic band 80 is adjustable to accommodate users with different head circumferences. Specifically, the elastic band 80 can be an elastic band that can stretch and contract to accommodate users with different head circumferences.
[0053] In one embodiment, such as Figure 2As shown, the outer casing 10 is provided with a connecting ear 121, and the elastic band 80 is provided with a male hook and loop fastener and a female hook and loop fastener. After the elastic band 80 passes around the connecting ear 121, the male hook and loop fastener and the female hook and loop fastener are bonded together, thereby realizing the installation of the elastic band 80 on the outer casing 10. Of course, the elastic band 80 can also be installed in other ways, which are not limited. For example, both ends of the elastic band 80 can be inserted into the interior of the outer casing 10 for fixation.
[0054] In one embodiment, combined Figure 1 and Figure 2 As shown, the outer casing 10 includes a front shell 11, a middle frame 12, and a bottom shell 13 connected in sequence. A viewing window 111 is opened on the front shell 11. The functional components 30 are disposed on the front shell 11. The display module 20, the circuit board 50, and the distance sensor 40 are all mounted on the middle frame 12. The battery 60 is installed inside the bottom shell 13. Specifically, the front shell 11 and the bottom shell 13 can be fixed to the middle frame 12 with screws. The display module 20 and the circuit board 50 can be fixed to the middle frame 12 with screws. The distance sensor 40 can be glued to the middle frame 12 with adhesive. The battery 60 can be glued to the bottom shell 13 with adhesive.
[0055] In one embodiment, the vision training device further includes a voice broadcast module, which is fixedly connected to the housing 10. The voice broadcast module works in conjunction with the display module 20 to provide users with a training program that combines visual and auditory learning, creating an immersive environment that can relax the mind and body and relieve fatigue.
[0056] The above are merely preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.
Claims
1. A vision training device, characterized in that, The device includes a housing, a display module, and functional components. A window is provided on one side of the housing. The display module is disposed inside the housing and corresponds to the window. The functional components are disposed on the side of the housing with the window. The functional components include massage protrusions and conductive elements. The conductive elements are capable of collecting bioelectric currents from the eye muscles.
2. The vision training device according to claim 1, characterized in that: The massage protrusion is disposed on the outer shell, and the conductive element is disposed on the massage protrusion.
3. The vision training device according to claim 2, characterized in that: The massage protrusion includes a package and a vibration component disposed within the package. One end of the package is connected to the outer shell, and a through hole is provided at the end of the package away from the outer shell. The conductive component includes an internal part and an external part. One side of the internal part abuts against the vibration component, and the other side of the internal part abuts against the inner wall of the package. The external part is connected to the internal part and extends out of the package through the through hole.
4. The vision training device according to claim 1, characterized in that: The massage protrusion includes an encapsulation body and a vibration component. The encapsulation body is connected to the outer shell, and the vibration component is disposed within the encapsulation body.
5. The vision training device according to claim 4, characterized in that: The encapsulation body is integrally formed with the outer shell.
6. The vision training device according to claim 1, characterized in that: The vision training device also includes a distance sensor, which is disposed on the side of the housing where the window is located or disposed inside the housing and corresponds to the window.
7. The vision training device according to any one of claims 1-6, characterized in that: The number of functional components is multiple, and the multiple functional components are arranged around the window.
8. The vision training device according to any one of claims 1-6, characterized in that: The vision training device also includes a circuit board and a battery. The circuit board and the battery are both disposed inside the housing. The battery, the display module and the conductive components are all electrically connected to the circuit board.
9. The vision training device according to any one of claims 1-6, characterized in that: The vision training device also includes an optical component, which is disposed inside the housing and located between the display module and the window. Light emitted from the display module passes through the optical component and shines onto the window.
10. The vision training device according to any one of claims 1-6, characterized in that: The vision training device also includes an elastic band, both ends of which are connected to the outer shell.