Transmission structure and electric turnover video and television lamp

Abstract

The application relates to a transmission structure and an electric turnover movie projector lamp and belongs to the technical field of lighting equipment. The transmission structure comprises a shell, a driving motor, a worm, a worm wheel, a gear, a first rotating shaft, a second rotating shaft and an angle detection assembly are arranged in the shell; the output shaft of the driving motor is connected with the worm, the worm wheel and the gear are coaxially connected through the first rotating shaft, the worm is engaged with the worm wheel, and a sector gear engaged with the gear is arranged on the second rotating shaft; the angle detection assembly comprises a first magnet arranged on the sector gear and a first magnetic field sensor arranged in the shell, and the first magnet and the first magnetic field sensor are matched to detect the rotating angle of the sector gear. According to the scheme, the rotating angle of the sector gear is detected in real time through the cooperation of the magnet and the magnetic field sensor, and the problems of wear error of a traditional mechanical limiting switch and complexity of sensor integration are solved.

Description

Technical Field

[0001] This application relates to the field of lighting equipment technology, and in particular to a transmission structure and an electric flip-up video lamp. Background Technology

[0002] In stage lighting, film and television shooting, and other fields, adjusting the pitch angle of lighting fixtures is an indispensable part of the lighting process. Currently, some electrically adjustable lighting fixtures use gear transmission structures to drive the lamp head to rotate, but their angle detection mostly relies on mechanical limit switches or photoelectric encoders. Mechanical limit switches are prone to wear due to frequent contact, leading to a decrease in detection accuracy; while photoelectric encoders, although highly accurate, suffer from drawbacks such as complex structure, high cost, and weak anti-interference capabilities. Furthermore, traditional gear transmission systems often experience lamp head angle shifts or drooping under power failure or external disturbances due to insufficient gear backlash or self-locking performance, requiring repeated calibration and severely affecting operational stability. Utility Model Content

[0003] To overcome the problems existing in related technologies, this application provides a transmission structure that uses a magnet and a magnetic field sensor to detect the rotation angle of the sector gear in real time, thus solving the problems of wear error in traditional mechanical limit switches and the complexity of sensor integration.

[0004] The first aspect of this application provides a transmission structure, including a housing, wherein a drive motor, a worm gear, a worm wheel, a gear, a first rotating shaft, a second rotating shaft, and an angle detection component are disposed within the housing;

[0005] The output shaft of the drive motor is connected to a worm gear, the worm wheel and the gear are coaxially connected through a first rotating shaft, the worm gear meshes with the worm wheel, and a sector gear meshing with the gear is provided on the second rotating shaft;

[0006] The angle detection component includes a first magnet disposed on the sector gear and a first magnetic field sensor disposed inside the housing. The first magnet and the first magnetic field sensor cooperate to detect the rotation angle of the sector gear.

[0007] In some embodiments, the rotation angle of the sector gear is 60° to 90°.

[0008] In some embodiments, the sector gear has an isosceles triangular structure.

[0009] In some embodiments, the first rotating shaft is mounted on the housing via a first bushing and a second bushing.

[0010] In some embodiments, one end of the gear extends outward to form a ring, the worm gear has a circular hole for the ring to pass through, the outer periphery of the ring has ribs arranged axially, the inner wall of the circular hole has a groove that matches the ribs, and the gear is rotatably connected to the first rotating shaft through a bearing.

[0011] In some embodiments, the housing is provided with a first bearing seat and a second bearing seat, both of which are provided with bearings;

[0012] The second rotating shaft includes a mounting base, a first cylinder, a second cylinder, a prism, and a third cylinder. The first cylinder, the second cylinder, the prism, and the third cylinder are connected in sequence and coaxially arranged. The first cylinder is connected to the mounting base. The sector gear has a through hole adapted to the prism. The bearing of the first bearing seat is fitted with the second cylinder, and the bearing of the second bearing seat is fitted with the third cylinder. The mounting base is located on the outside of the housing.

[0013] In some embodiments, the housing includes a bottom plate and a cover plate, both of which are flat plates. The bottom plate is vertically provided with a plurality of support columns, which are connected to the cover plate. The first magnetic field sensor is disposed on the cover plate.

[0014] The first bearing housing is fixed to the base plate by bolts, the second bearing housing is fixed to the cover plate by bolts, and the mounting base is located on the side of the base plate away from the cover plate.

[0015] In some embodiments, the drive motor is a variable speed stepper motor, the gear is a variable speed gear, the end of the worm gear is connected to a bearing, the outer ring of the bearing is disposed on a motor bearing housing, and the motor bearing housing is disposed on a housing.

[0016] The second aspect of this application is to provide an electric flip-type video light, including a light box, a lamp head, and the aforementioned transmission structure. The light box has a downward-facing opening, the lamp head is housed within the opening, and one end of the lamp head is provided with a driven rotating shaft. The light box is provided with a driven rotating bearing, the driven rotating shaft is inserted into the driven rotating bearing, and the other end of the lamp head is connected to a second rotating shaft of the transmission structure.

[0017] In some embodiments, the light box includes a chassis, in which a motherboard is installed. The motherboard is connected to a power module, a display module, a signal control module, a cooling fan, a limit switch, a switching power supply module, and a second magnetic field sensor. The lamp head is provided with a second magnet, which cooperates with the second magnetic field sensor to detect the rotation angle of the lamp head.

[0018] The technical solution provided in this application may include the following beneficial effects:

[0019] The transmission structure provided by this utility model is applied to an electric tilting video light. This transmission structure is used to adjust the light angle of the electric tilting video light. It utilizes the output shaft of a drive motor to drive a worm gear to rotate. The meshing of the worm gear and worm wheel drives the worm wheel and a coaxially connected gear to rotate. The gear drives a sector gear meshing with it to oscillate around a second rotation axis. A first magnet on the sector gear generates a magnetic field change as the gear rotates. A first magnetic field sensor inside the housing detects the magnetic field strength shift in real time, converting the mechanical rotation angle into an electrical signal output, forming a closed-loop angle feedback. Compared to existing technologies, the non-contact interaction between the magnet and the magnetic field sensor eliminates the physical wear problem of mechanical limit switches. The magnetic field sensor directly captures the rotation information of the sector gear, avoiding overload of the drive motor. It has the advantages of short response time, strong anti-interference ability, and simplification. Attached Figure Description

[0020] The above and other objects, features and advantages of this application will become more apparent from the more detailed description of exemplary embodiments thereof in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same components in the exemplary embodiments thereof.

[0021] Figure 1 This is a schematic diagram of the transmission structure shown in the embodiments of this application;

[0022] Figure 2 This is another schematic diagram of the transmission structure shown in the embodiments of this application;

[0023] Figure 3 This is another schematic diagram of the transmission structure shown in the embodiments of this application;

[0024] Figure 4 This is an exploded schematic diagram of the transmission structure shown in the embodiments of this application;

[0025] Figure 5 This is a schematic diagram of the gear structure shown in the embodiments of this application;

[0026] Figure 6 This is a schematic diagram of the structure of the second rotating shaft shown in an embodiment of this application;

[0027] Figure 7 This is a schematic diagram of the sector gear structure shown in the embodiments of this application;

[0028] Figure 8 This is a schematic diagram of the structure of the electric flip-up video lamp shown in the embodiments of this application;

[0029] Figure 9 This is another structural schematic diagram of the electrically operated flip-up video lamp shown in the embodiments of this application;

[0030] Figure 10This is another structural schematic diagram of the electrically rotating video lamp shown in the embodiments of this application.

[0031] Figure label:

[0032] 1. Transmission structure; 100. Housing; 100a. Base plate; 100b. Cover plate; 100c. Support column; 101. Drive motor; 102. Worm gear; 103. Worm wheel; 104. Gear; 105. First rotating shaft; 106. Second rotating shaft; 106a. Mounting base; 106b. First cylinder; 106c. Second cylinder; 106d. Prism; 106e. Third cylinder; 107. Angle detection assembly; 108. Sector gear; 109. First bushing; 110. Second bushing; 111. Ring; 112. Rib; 113. First bearing housing; 114. Second bearing housing; 115. Motor bearing housing;

[0033] 2. Light box; 200. Chassis; 201. Power supply module; 202. Display module; 203. Signal control module; 204. Cooling fan; 205. Limit switch; 206. Switching power supply module; 207. Second magnetic field sensor; 3. Lamp holder; 300. Driven rotating shaft; 301. Driven rotating bearing. Detailed Implementation

[0034] Preferred embodiments of the present application will now be described in more detail with reference to the accompanying drawings. While preferred embodiments of the present application are shown in the drawings, it should be understood that the present application may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to make the present application more thorough and complete, and to fully convey the scope of the present application to those skilled in the art.

[0035] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The singular forms “a,” “the,” and “the” used in this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0036] It should be understood that although the terms "first," "second," "third," etc., may be used in this application to describe various information, this information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, without departing from the scope of this application, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. 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.

[0037] The technical solutions of the embodiments of this application are described in detail below with reference to the accompanying drawings.

[0038] This utility model embodiment provides a transmission structure 1, applied to an electrically operated tilting video light. The transmission structure 1 adjusts the light angle of the electrically operated tilting video light. (See also...) Figures 1 to 7 The transmission structure 1 includes a housing 100, which contains a drive motor 101, a worm gear 102, a worm wheel 103, a gear 104, a first rotating shaft 105, a second rotating shaft 106, and an angle detection component 107.

[0039] The output shaft of the drive motor 101 is connected to the worm 102, the worm wheel 103 and the gear 104 are coaxially connected through the first rotating shaft 105, the worm 102 and the worm wheel 103 mesh with each other, and the second rotating shaft 106 is provided with a sector gear 108 that meshes with the gear 104.

[0040] The angle detection component 107 includes a first magnet disposed on the sector gear 108 and a first magnetic field sensor disposed inside the housing 100. The first magnet and the first magnetic field sensor cooperate to detect the rotation angle of the sector gear 108.

[0041] Specifically, the housing 100 is used to mount the electric flip-up video lamp and the main structural components for housing the transmission structure 1. The housing 100 is made of PC material, the worm gear 103 is made of POM material with a friction coefficient ≤0.2, the gear 104 and the sector gear 108 are made of glass fiber reinforced nylon with a bending strength ≥120MPa, the first rotating shaft 105 is made of stainless steel with a nitrided surface, the first magnet is mounted on the sector gear 108, and the first magnetic field sensor can be a reed switch, a magnetoresistive sensor, or a Hall sensor. In a preferred embodiment, the first magnetic field sensor is a triaxial Hall sensor. The triaxial Hall sensor is mounted on a circuit board using SMT technology, and the circuit board is fixed in the housing 100 with screws. The first magnet is embedded in the end face of the sector gear 108, and its N / S pole direction is perpendicular to the rotation plane of the sector gear 108. The outer edge of the magnet can also be provided with an anti-detachment groove, which is fixed by a nylon retainer ring. The end face of the sector gear 108 is provided with a mounting hole for fixing the nylon retainer ring. The gap between the Hall sensor and the first magnet on the sector gear 108 is 2mm, which ensures that the gap between the magnet and the first magnetic field sensor is constant, realizes non-contact angle detection, and avoids mechanical wear. The worm 102 meshes with the worm wheel 103, and the gear 104 meshes with the sector gear 108. The worm wheel 103 and gear 104 rotate coaxially. The worm wheel 103 and worm 102 achieve self-locking and transmission. The output shaft of the drive motor 101 drives the worm 102 to rotate. The meshing of the worm 102 and worm wheel 103 drives the worm wheel 103 and the coaxially connected gear 104 to rotate. The gear 104 drives the sector gear 108, which meshes with it, to oscillate around the second rotation axis 106. The first magnet on the sector gear 108 generates a change in magnetic field as the gear 104 rotates. The first magnetic field sensor inside the housing 100 detects the magnetic field strength shift in real time and converts the mechanical rotation angle into an electrical signal output, forming a closed-loop angle feedback. Compared with the prior art, the non-contact cooperation between the magnet and the magnetic field sensor eliminates the physical wear problem of the mechanical limit switch. The magnetic field sensor directly captures the rotation information of the sector gear 108, which can avoid overloading the drive motor 101. It has the advantages of short response time, strong anti-interference ability, and simplification. In addition, the worm gear 103 and worm 102 have a self-locking function, which can achieve self-locking when disconnected from electricity, thus solving the problem of insufficient self-locking of the traditional transmission structure 1.

[0042] Furthermore, a controller connected to the electric tilting video light control system can be installed inside the housing 100, or a module for controlling the drive motor 101 and the first magnetic field sensor can be integrated into the electric tilting video light control system. This controller or module can be driven and controlled using Wi-Fi, infrared remote control, or other methods.

[0043] Furthermore, the rotation angle of the sector gear 108 is 60° to 90°. Setting the rotation angle of the sector gear 108 to 60° to 90° optimizes the movement range of the film and television light's rotation, meets actual lighting requirements, and avoids mechanical stress concentration caused by excessive rotation, thus extending the service life of the transmission components. More specifically, the sector gear 108 has an isosceles triangular structure. The isosceles triangular structure of the sector gear 108 enhances the symmetry and stability of gear meshing. The sector gear 108 has an arc-shaped gear meshing surface and two perpendicularly intersecting side surfaces. When the sector gear 108 rotates, the two side surfaces can fit against the side wall of the housing 100, reducing the volume space occupied by the sector gear 108 in the housing 100, thereby reducing the overall size of the transmission structure 1 and facilitating the installation of the transmission structure 1 from the side of the electrically rotating film and television light.

[0044] Furthermore, the first rotating shaft 105 is mounted on the housing 100 via a first bushing 109 and a second bushing 110. The first bushing 109 and the second bushing 110 are copper tubes and are connected and fixed to the housing 100 by bolts.

[0045] Furthermore, one end of the gear 104 extends outward to form a ring 111. The worm gear 103 has a circular hole through which the ring 111 passes. The outer periphery of the ring 111 has ribs 112 arranged axially. The inner wall of the circular hole has a groove that mates with the ribs 112. The gear 104 is rotatably connected to the first rotating shaft 105 via a bearing. Through the first bushing 109, the second bushing 110, and the mating structure of the ring 111 of the gear 104 and the ribs 112-groove of the worm gear 103, precise positioning and axial limiting of the rotating shaft are achieved, effectively reducing frictional loss during transmission, improving transmission efficiency, and preventing axial displacement of the gear 104 and the worm gear 103.

[0046] Furthermore, the housing 100 is provided with a first bearing seat 113 and a second bearing seat 114, both of which are provided with bearings.

[0047] The second rotating shaft 106 includes a mounting base 106a, a first cylinder 106b, a second cylinder 106c, a prism 106d, and a third cylinder 106e. The first cylinder 106b, the second cylinder 106c, the prism 106d, and the third cylinder 106e are connected sequentially and coaxially. The first cylinder 106b is connected to the mounting base 106a. The sector gear 108 has a through hole adapted to the prism 106d. The bearing of the first bearing seat 113 is fitted with the second cylinder 106c, and the bearing of the second bearing seat 114 is fitted with the third cylinder 106e. The mounting base 106a... 6a is located on the outside of the housing 100. The material of the second rotating shaft 106 can be metal or plastic. In a preferred embodiment, the mounting base 106a, the first cylinder 106b, the second cylinder 106c, the prism 106d, and the third cylinder 106e are integrally formed by injection molding. The mounting base 106a is used to connect with the lamp head 3 in the electric rotating video lamp. The diameters of the first cylinder 106b, the second cylinder 106c, the prism 106d, and the third cylinder 106e gradually decrease so that the second rotating shaft 106 can be smoothly inserted into the first bearing seat 113, the sector gear 108, and the second bearing seat 114. When assembling the electric rotating video lamp, the outside of the housing 100 is positioned opposite the lamp head 3, with a certain gap between them. The mounting base 106a is located in this gap, and the housing 100 and the lamp head 3 act as limiters, thereby fixing the second rotating shaft 106 onto the housing 100.

[0048] Furthermore, the housing 100 includes a bottom plate 100a and a cover plate 100b. Both the bottom plate 100a and the cover plate 100b are flat plates. The bottom plate 100a is vertically provided with a plurality of support columns 100c. The support columns 100c are connected to the cover plate 100b. The first magnetic field sensor is disposed on the cover plate 100b.

[0049] The first bearing housing 113 is bolted to the base plate 100a, and the second bearing housing 114 is bolted to the cover plate 100b. The mounting base 106a is located on the side of the base plate 100a facing away from the cover plate 100b. The base plate 100a and the cover plate 100b constitute a split design of the housing 100, while the first bearing housing 113 and the second bearing housing 114 constitute a modular bearing design, which facilitates assembly and maintenance. This reduces the weight of the housing 100 while maintaining its rigidity through the support column 100c. In some embodiments, to reduce the detection accuracy of the second magnetic field sensor 207 by the support column 100c and to ensure the rigidity of the housing 100, the support column 100c is made of copper.

[0050] Furthermore, the drive motor 101 is a variable-speed stepper motor, the gear 104 is a variable-speed gear, and a bearing is connected to the end of the worm gear 102. The outer ring of the bearing is mounted on the motor bearing housing 115, which is mounted on the housing 100. The variable-speed stepper motor and the worm gear 102 are combined for transmission, utilizing their dual self-locking function, namely motor resistance self-locking and worm gear 102 reverse self-locking, to maintain the fixed angle of the lamp head 3 even under power failure or external interference, completely solving the problem of lamp head 3 sagging caused by backlash in traditional gear transmissions.

[0051] In summary, compared to existing technologies, the transmission structure 1 provided by this utility model utilizes a first magnetic field sensor to provide real-time feedback of angle data. The variable-speed stepper motor dynamically adjusts its speed based on this feedback angle data, precisely controlling the movement of the sector gear 108 within the range of 60° to 90°. For example, when the lamp head 3 flips, the first magnetic field sensor detects an angle deviation of 0.5°, and the variable-speed stepper motor immediately compensates and corrects it, avoiding the hysteresis error of traditional encoders.

[0052] Based on the above embodiments, this utility model also provides an electrically operated rotating video light, having any of the transmission structures 1 described in the above embodiments. Please refer to [link / reference needed]. Figures 8 to 10 The air conditioner also includes a light box 2 and a light head 3.

[0053] Specifically, the lamp box 2 has an opening facing downwards, the lamp head 3 is housed in the opening, and one end of the lamp head 3 is provided with a driven rotating shaft 300. The lamp box 2 is provided with a driven rotating bearing 301, and the driven rotating shaft 300 is inserted into the driven rotating bearing 301. The other end of the lamp head 3 is connected to the second rotating shaft 106 of any of the transmission structures 1 in the above embodiments.

[0054] Furthermore, the light box 2 includes a chassis 200, within which a motherboard is installed. The motherboard is connected to a power module 201, a display module 202, a signal control module 203, a cooling fan 204, a limit switch 205, a switching power supply module 206, and a second magnetic field sensor 207. The lamp head 3 is equipped with a second magnet, which cooperates with the second magnetic field sensor 207 to detect the rotation angle of the lamp head 3. The second magnetic field sensor 207 and the second magnet serve as a backup detection scheme. When the first magnetic field sensor fails to function properly, the control module on the motherboard can obtain the rotation angle of the lamp head 3 through the second magnetic field sensor 207. For example, when the first magnetic field sensor detects an angle fluctuation exceeding ±2° or signal loss three consecutive times, the signal control module 203 automatically switches to the second magnetic field sensor 207 and triggers an alarm signal. After the fault is cleared, the main sensor detection mode is restored by pressing the reset button.

[0055] It is understandable that lamp holder 3 is a mature application of existing technology, and will not be described in detail here.

[0056] In this embodiment, the transmission structure 1 is integrated with the light box 2, the lamp head 3 and the control module, realizing the integration of electric flipping, precise angle adjustment and intelligent control of the film and television lamp, which significantly improves the operating efficiency and lighting flexibility of the equipment. At the same time, the redundant design of Hall switch and limit switch 205 further ensures the safety and reliability of the system.

[0057] The various embodiments of this application have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A transmission structure, characterized in that, Includes a housing (100), which contains a drive motor (101), a worm (102), a worm wheel (103), a gear (104), a first rotating shaft (105), a second rotating shaft (106), and an angle detection assembly (107); The output shaft of the drive motor (101) is connected to the worm (102), the worm wheel (103) and the gear (104) are coaxially connected through the first rotating shaft (105), the worm (102) and the worm wheel (103) mesh with each other, and the second rotating shaft (106) is provided with a sector gear (108) that meshes with the gear (104); The angle detection component (107) includes a first magnet disposed on the sector gear (108) and a first magnetic field sensor disposed in the housing (100). The first magnet and the first magnetic field sensor cooperate to detect the rotation angle of the sector gear (108).

2. The transmission structure according to claim 1, characterized in that, The rotation angle of the sector gear (108) is 60° to 90°.

3. The transmission structure according to claim 2, characterized in that, The sector gear (108) has an isosceles triangular structure.

4. The transmission structure according to claim 1, characterized in that, The first rotating shaft (105) is mounted on the housing (100) via a first bushing (109) and a second bushing (110).

5. The transmission structure according to claim 4, characterized in that, One end of the gear (104) extends outward to form a ring (111). The worm gear (103) is provided with a circular hole through which the ring (111) passes. The outer periphery of the ring (111) is provided with ribs (112) arranged along the axial direction. The inner wall of the circular hole is provided with a groove that matches the ribs (112). The gear (104) is rotatably connected to the first rotating shaft (105) through a bearing.

6. The transmission structure according to claim 1, characterized in that, The housing (100) is provided with a first bearing seat (113) and a second bearing seat (114), both of which are provided with bearings; The second rotating shaft (106) includes a mounting base (106a), a first cylinder (106b), a second cylinder (106c), a prism (106d), and a third cylinder (106e). The first cylinder (106b), the second cylinder (106c), the prism (106d), and the third cylinder (106e) are connected in sequence and coaxially arranged. The first cylinder (106b) is connected to the mounting base (106a). The sector gear (108) is provided with a through hole that matches the prism (106d). The bearing of the first bearing seat (113) is fitted with the second cylinder (106c), and the bearing of the second bearing seat (114) is fitted with the third cylinder (106e). The mounting base (106a) is located on the outside of the housing (100).

7. The transmission structure according to claim 6, characterized in that, The housing (100) includes a base plate (100a) and a cover plate (100b). Both the base plate (100a) and the cover plate (100b) are flat plates. The base plate (100a) is vertically provided with a plurality of support columns (100c). The support columns (100c) are connected to the cover plate (100b). The first magnetic field sensor is disposed on the cover plate (100b). The first bearing housing (113) is fixed to the base plate (100a) by bolts, the second bearing housing (114) is fixed to the cover plate (100b) by bolts, and the mounting seat (106a) is located on the side of the base plate (100a) away from the cover plate (100b).

8. The transmission structure according to claim 1, characterized in that, The drive motor (101) is a variable speed stepper motor, the gear (104) is a variable speed gear, the end of the worm (102) is connected to a bearing, the outer ring of the bearing is disposed on the motor bearing seat (115), and the motor bearing seat (115) is disposed on the housing (100).

9. An electrically operated rotating video light, characterized in that, The device includes a light box (2), a lamp head (3), and a transmission structure (1) as described in any one of claims 1 to 8. The light box (2) has an opening facing downwards. The lamp head (3) is housed in the opening. One end of the lamp head (3) is provided with a driven rotating shaft (300). The light box (2) is provided with a driven rotating bearing (301). The driven rotating shaft (300) is inserted into the driven rotating bearing (301). The other end of the lamp head (3) is connected to the second rotating shaft (106) of the transmission structure (1).

10. The electrically operated rotating video light according to claim 9, characterized in that, The light box (2) includes a chassis (200), in which a motherboard is installed. The motherboard is connected to a power module (201), a display module (202), a signal control module (203), a cooling fan (204), a limit switch (205), a switching power supply module (206), and a second magnetic field sensor (207). The lamp head (3) is provided with a second magnet, which cooperates with the second magnetic field sensor (207) to detect the rotation angle of the lamp head (3).

Images