A light adjusting device, a preparation method thereof and a light reflection preventing signal lamp

Abstract

The application relates to the technical field of signal lamps, in particular to a light adjusting device and a preparation method thereof and a light reflection prevention signal lamp, which comprises a transparent sealing module and a microstructure module. A containing cavity is arranged in the transparent sealing module; a plurality of microstructure modules are arranged in an array in the containing cavity; the microstructure module comprises a light adjusting unit and a stability maintaining unit connected with the light adjusting unit; one end of the light adjusting unit is rotationally arranged in the containing cavity, so that the light adjusting unit has a light transmission position and a light shielding position; when the light adjusting unit is at the light transmission position, a light transmission gap for light transmission is formed between adjacent light adjusting units; when the light adjusting unit is at the light shielding position, edges of adjacent light adjusting units are overlapped with each other to shield light passing through the transparent sealing module; the stability maintaining unit has two stable equilibrium positions to lock the light adjusting unit at the light transmission position or the light shielding position in a state without power supply. The application has the effect of reducing the risk of false light.

Description

Technical Field

[0001] This application relates to the technical field of optical devices for microelectromechanical systems (MEMS), and in particular to a dimming device, its fabrication method, and an anti-reflective signal light. Background Technology

[0002] Currently, LED signal lights are widely used in railway transportation systems to convey train operation instructions to train drivers and are key equipment for ensuring railway operation safety. LED signal lights are typically installed beside the track or at a high location, with a transparent front cover and a light-emitting bowl inside the lamp cavity for reflecting and focusing light. Under normal operating conditions, the light emitted by the LED beads is reflected by the light-emitting bowl and then emitted through the transparent front cover, forming a clearly identifiable signal indication.

[0003] However, in actual operating environments, when strong sunlight shines on LED signal lights at a specific angle, the sunlight can penetrate the transparent front cover and enter the lamp cavity, then be reflected by the light-emitting bowl and emitted from the front of the signal light. When the signal light is off, this reflected ambient light can cause the signal light surface to appear as if it is lit, leading train drivers to mistakenly believe the signal light is on—a phenomenon known as "false lighting." This phenomenon seriously threatens driving safety, potentially causing drivers to misinterpret signals, resulting in reckless driving or incorrect operational decisions.

[0004] In related technologies, the following solutions are mainly used to address the problem of false traffic light illumination: The first type is passive optical solutions, such as adding a sunshade or light-shielding tube to the front of the traffic light. This reduces the possibility of sunlight entering the lamp cavity by limiting the incident angle of external light. However, the size and angle of the sunshade are fixed and cannot adapt to all-weather, all-round changes in the sun's angle, and false brightness can still occur at certain specific angles. Another solution is to use matte anti-glare glass as the traffic light cover, reducing the intensity of reflected light by lowering the specular reflectivity of the front cover surface. For example, Chinese patent CN 218601945U discloses a traffic light that prevents sunlight reflection by embedding matte anti-glare glass inside the lamp cover to reduce interference from ambient light. However, matte anti-glare glass is a fixed optical treatment; its anti-glare effect is determined after manufacturing and cannot be dynamically adjusted according to real-time changes in external lighting conditions. In all-weather environments where the angle and intensity of sunlight continuously change, the risk of false brightness still exists. Furthermore, while reducing external reflected light, the matte finish also scatters the signal light emitted by the traffic light itself, reducing the brightness and clarity of the signal light.

[0005] The second category is optical filtering solutions. For example, polarizers or narrowband filters are placed on the inside of the signal light's front cover to distinguish signal light from ambient reflected light using polarization characteristics or spectral selectivity. However, polarizers lose about 50% of the signal light intensity, severely affecting the visibility and recognition effect of the signal light. Narrowband filters have limited suppression effect on broadband sunlight and are difficult to effectively block ambient light components with wavelengths similar to the signal light. In addition, optical components such as polarizers and filters are prone to aging and discoloration under long-term outdoor high temperature, ultraviolet radiation, and alternating hot and humid conditions, leading to a gradual deterioration of optical performance.

[0006] The third type is electronic dimming solutions. For example, electrochromic glass or polymer-dispersed liquid crystal (PDLC) dimming devices are used, changing the light transmittance of the material by applying voltage. However, electrochromic materials have a slow response speed; switching from a transparent to an opaque state typically takes several seconds to tens of seconds, which cannot meet the rapid response requirements of railway signal lights. PDLC dimming devices are in a scattering state (semi-transparent) when power is off, failing to achieve complete light blocking; strong external light can still partially pass through, resulting in incomplete light blocking.

[0007] Therefore, the above-mentioned anti-false lighting technology solutions cannot completely, quickly and with low power consumption block external ambient light from entering the lamp cavity when the signal light is off, and the risk of false lighting still exists. Summary of the Invention

[0008] To reduce the risk of false brightness, this application provides a dimming device, its preparation method, and an anti-reflective signal light.

[0009] Firstly, this application provides a dimming device that adopts the following technical solution: A dimming device, comprising: A transparent sealing module, wherein a receiving cavity is provided inside the transparent sealing module; Multiple microstructure modules are provided, and the multiple microstructure modules are arranged in an array in the receiving cavity. Each microstructure module includes a dimming unit and a stabilization unit connected to the dimming unit. One end of the dimming unit is rotatably disposed in the receiving cavity, and the other end of the dimming unit is a free end, so that the dimming unit can be flipped to have light-transmitting and light-blocking positions. When the dimming unit is in the light-transmitting position, a light-transmitting gap is formed between adjacent dimming units to allow light to pass through. When the dimming unit is in the light-blocking position, the edges of adjacent dimming units overlap to block the light passing through the transparent sealing module. The stabilization unit has two steady-state equilibrium positions, which correspond to the light-transmitting and light-blocking positions, respectively, so as to lock the dimming unit in the light-transmitting or light-blocking position when there is no power supply.

[0010] By adopting the above technical solution, multiple microstructure modules are arranged in an array within the receiving cavity and cover the cavity. When the dimming unit is in the light-transmitting position, a light-transmitting gap is formed between adjacent dimming units, allowing light to pass smoothly through the transparent sealed module, ensuring good light transmittance of the dimming device in the light-transmitting state. When the dimming unit is in the light-blocking position, adjacent dimming units overlap each other, effectively blocking light passing through the transparent sealed module, avoiding interference from external light, and thus eliminating the phenomenon of false lighting of the signal light caused by ambient light interference. At the same time, the stabilization unit adopts a bistable mechanism, which has two stable positions corresponding to the light-transmitting and light-blocking positions respectively. This allows the dimming unit to maintain its current state without external energy after switching to the light-transmitting or light-blocking position, requiring only a brief drive pulse during state switching, effectively reducing the power consumption of the dimming device.

[0011] Optionally, it also includes a driving module. The transparent sealing module includes a transparent substrate and a transparent cover layer that is sealed to the transparent substrate. The receiving cavity is formed between the transparent substrate and the transparent cover layer. A conductive layer is disposed on the side of the transparent substrate near the transparent cover layer. A plurality of dimming units are arranged in an array on the conductive layer. One end of the dimming unit is rotatably disposed on the conductive layer. The conductive layer includes multiple independent bottom electrodes, each corresponding to a dimming unit. A top electrode is provided on the side of the transparent cover layer near the conductive layer. The bottom electrodes and the top electrodes are electrically connected to the driving module. The driving module is used to apply voltage pulses between the bottom electrodes and the top electrodes to drive the dimming unit to switch between light-transmitting and light-blocking positions.

[0012] By adopting the above technical solution, the transparent sealing module is composed of a transparent substrate and a transparent cover layer sealed together, forming a sealed cavity between them. This encapsulates the dimming unit and the stabilization unit in a sealed environment, reducing the impact of dust and moisture from the external environment on the microstructure. The conductive layer is patterned into multiple independent bottom electrodes, which, in conjunction with the top electrode on the transparent cover layer, allow the dimming unit to be flipped by applying voltage pulses to the driving module using electrostatic force. This enables rapid switching of the dimming unit between light-transmitting and light-blocking positions. The bottom and top electrodes are respectively located on both sides of the dimming unit, providing downward and upward electrostatic attraction, respectively, thereby achieving bidirectional driving of the dimming unit.

[0013] Optionally, two anchor points are provided on the inner wall of the receiving cavity, and the dimming unit is rotatably connected to the two anchor points respectively. The stabilization unit includes a buckling beam and a flexible linkage arm. The two ends of the buckling beam are fixed to the two anchor points respectively. The length of the buckling beam is greater than the straight distance between the two anchor points, so that the buckling beam is under axial compression and has two steady-state buckling directions of upward and downward arching. One end of the flexible linkage arm is located in the middle of the buckling beam, and the other end of the flexible linkage arm is connected to the dimming unit.

[0014] By adopting the above technical solution, the length of the buckling beam is greater than the straight-line distance between the two anchor points, so that the buckling beam is in an axially compressed state after installation, with two stable buckling directions: upward and downward. These two steady-state directions correspond to the light-transmitting and light-blocking positions of the dimming unit, respectively. The flexible linkage arm connects the middle of the buckling beam to the free end of the dimming unit. When the dimming unit is flipped under electrostatic force, the flexible linkage arm drives the buckling beam to jump from one steady-state buckling direction to another. The buckling beam has the lowest potential energy point at the new steady-state position, so it can be maintained in the current position without external force, thus realizing the passive locking of the dimming unit.

[0015] Optionally, an anchor point is provided on the inner wall of the receiving cavity, and the dimming unit is rotatably connected to the anchor point. The stabilization unit includes a guide rail, a sliding member, and a Z-shaped hinge. The guide rail is provided on the inner wall of the receiving cavity, and a locking structure is provided at both ends of the guide rail. The sliding member is slidably disposed on the guide rail. When the sliding member slides to the locking structure, the locking structure locks with the sliding member. One end of the Z-shaped hinge is connected to the dimming unit, and the other end of the Z-shaped hinge is connected to the sliding member.

[0016] By adopting the above technical solution, when the dimming unit flips under electrostatic force, the flipping motion is converted into the linear sliding motion of the slider along the guide rail via a Z-shaped hinge. The locking structures at both ends of the guide rail correspond to the light-transmitting and light-blocking positions of the dimming unit, respectively. When the slider slides to the locking structure, the locking structure locks with the slider, thereby locking the dimming unit in its current position. The Z-shaped hinge enables motion conversion between the rotational motion of the dimming unit and the linear motion of the slider.

[0017] Optionally, multiple microstructure modules are arranged in an array along the row and column directions. When the dimming unit is in the light-shielding position, the edges of two adjacent dimming units in the same row overlap each other, and the area of ​​the overlapping part accounts for 10%-15% of the surface area of ​​a single dimming unit.

[0018] By adopting the above technical solution, when the dimming unit is in the light-shielding position, the edges of two adjacent dimming units in the same row overlap, and the area of ​​the overlap portion accounts for 10%-15% of the surface area of ​​a single dimming unit. This helps to ensure that there are no light leakage gaps between adjacent dimming units in the light-shielding state, thus improving the light-shielding effect of the dimming device in the light-shielding state. At the same time, the 10%-15% overlap ratio reduces the overlapping area while ensuring the light-shielding effect, thereby maintaining a high light transmittance in the light-transmitting state.

[0019] Secondly, this application provides a method for fabricating a dimming device, employing the following technical solution: A method for fabricating a dimming device includes the following steps: S1: Provide a transparent substrate, deposit a transparent conductive layer on the transparent substrate, and pattern the conductive layer using photolithography and etching processes to form multiple bottom electrodes arranged in an array; S2: Deposit a sacrificial layer on the conductive layer, the sacrificial layer covering the bottom electrode, and form an anchoring hole through the sacrificial layer by photolithography and etching processes; S3: Deposit a structural layer on the sacrificial layer and inside the anchoring hole; S4: The structural layer is patterned by photolithography and etching processes to form a dimming unit pattern and a stabilization unit pattern; S5: Remove the sacrificial layer, so that the dimming unit pattern and the stabilization unit pattern are detached from the sacrificial layer and released into a suspended state; S6: Provide a transparent cover layer, deposit a top electrode material layer on one side surface of the transparent cover layer, pattern the top electrode material layer by photolithography and etching processes to form a top electrode, then seal the transparent cover layer to the transparent substrate so that the top electrode faces the dimming unit, and form a sealed receiving cavity between the transparent cover layer and the transparent substrate, wherein the dimming unit, the stabilization unit, the bottom electrode and the top electrode are all encapsulated in the receiving cavity.

[0020] Optionally, the sacrificial layer is made of silicon dioxide, and the structural layer is made of one of doped polycrystalline silicon, amorphous silicon, and silicon nitride. In S5, the sacrificial layer is removed by a hydrofluoric acid vapor etching process.

[0021] By adopting the above technical solution, the sacrificial layer is made of silicon dioxide, and the structural layer is made of doped polycrystalline silicon, amorphous silicon, or silicon nitride. These two types of materials exhibit good etching selectivity. Hydrofluoric acid vapor etching is preferably used to remove the sacrificial layer, which avoids the microstructure adhesion problem caused by liquid surface tension during wet etching. When wet etching is used, supercritical point drying treatment is required after release to prevent adhesion.

[0022] Optionally, step S7 is also included: connecting the electrode leads on the transparent substrate and the transparent cover layer to the flexible circuit board by thermo-press bonding with anisotropic conductive adhesive to form an electrical interface.

[0023] By employing the above technical solution, anisotropic conductive adhesive is used for thermosetting bonding to connect electrode leads to a flexible circuit board, forming an electrical interface. After thermosetting bonding, the anisotropic conductive adhesive conducts only in the thickness direction and remains insulating in the planar direction, thus enabling precise connection of high-density electrode leads and avoiding short circuits between adjacent leads. The flexible circuit board's bendable nature facilitates the connection and installation of dimming devices with external drive modules.

[0024] Thirdly, this application provides an anti-reflective signal light, which adopts the following technical solution: A light-reflecting signal light includes a signal light body and the aforementioned dimming device. The signal light body has a light outlet, and the dimming device is disposed at the light outlet and covers the light outlet.

[0025] By adopting the above technical solution, the dimming device is set at the light outlet of the main body of the signal light. When the signal light is lit, the dimming device switches to the light-transmitting state, and the light can pass through the dimming device and be emitted from the light outlet. When the signal light is turned off, the dimming device switches to the light-blocking state. When the external ambient light shines on the dimming device, it is blocked by the dimming unit array and cannot enter the lamp cavity, thus effectively eliminating the "false brightness" phenomenon.

[0026] Optionally, the main body of the signal light includes a lamp housing, a light-emitting bowl, a light source, and a control circuit board. The light outlet is located at the front end of the lamp housing. The light-emitting bowl is disposed inside the lamp housing and faces the light outlet. The light source is disposed at the bottom center of the light-emitting bowl. The control circuit board is disposed inside the lamp housing and is electrically connected to the light source and the dimming device, respectively.

[0027] By adopting the above technical solution, when the control circuit board receives the instruction to turn on the light source, it first switches the dimming unit to the light-transmitting position and then turns on the light source. At this time, the light emitted by the light source is reflected and focused by the light-emitting bowl, and can pass smoothly through the light-transmitting gap formed between the dimming units and be emitted from the light outlet at the front of the lamp housing, ensuring that the signal light can illuminate and display signals normally. When the control circuit board receives the instruction to turn off the light source, it first turns off the light source and switches the dimming unit to the light-blocking position. The adjacent dimming units overlap and block the light, which can effectively prevent external light such as strong sunlight from entering the lamp housing through the light outlet and being reflected out, avoiding the phenomenon of "false lighting" and ensuring the accuracy of the signal light display and driving safety.

[0028] In summary, this application includes at least one of the following beneficial technical effects: 1. The dimming device uses an array of microstructure modules to control the on / off state of light. Combined with the bistable locking function of the stabilization unit, it only needs to apply a short drive pulse when switching states and does not require power supply when maintaining the state, thus reducing power consumption. It also has the advantages of fast response speed and long service life. 2. The fabrication method of the dimming device adopts the standard MEMS surface micromachining process, which is mature and compatible with existing semiconductor manufacturing equipment, facilitating large-scale mass production and helping to reduce production costs; 3. By applying dimming devices to anti-reflective traffic lights, the control circuit board enables automatic and synchronized switching between the dimming device status and the LED light source status, thereby effectively eliminating the "false lighting" phenomenon of traffic lights and improving traffic safety. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the overall structure of a dimming device in an embodiment of this application.

[0030] Figure 2 It is along Figure 1 A cross-sectional view along line AA in the middle.

[0031] Figure 3 This is an enlarged structural schematic diagram of the microstructure module in Embodiment 1 of this application.

[0032] Figure 4 This is an enlarged structural schematic diagram of the microstructure module in Embodiment 2 of this application.

[0033] Figure 5 This is a schematic flowchart illustrating the fabrication method of the dimming device in the embodiments of this application.

[0034] Figure 6 This is a schematic diagram of the fabrication process of the dimming device in the embodiments of this application.

[0035] Figure 7 This is a schematic diagram of the overall structure of the anti-reflective signal light in the embodiment of this application.

[0036] Explanation of reference numerals in the attached figures: 1. Transparent sealing module; 11. Receiving cavity; 12. Transparent substrate; 13. Transparent covering layer; 14. Conductive layer; 15. Anchor point; 16. Sacrificial layer; 17. Structural layer; 2. Microstructure module; 21. Dimming unit; 22. Stabilizing unit; 221. Buckling beam; 222. Flexible linkage arm; 223. Guide rail; 2231. Positioning structure; 224. Sliding component; 225. Z-shaped hinge; 3. Drive module; 4. Signal light body; 41. Lamp housing; 411. Light outlet; 412. Transparent front cover; 42. Light-emitting bowl; 43. Light source. Detailed Implementation

[0037] The following is in conjunction with the appendix Figures 1-7 This application will be described in further detail.

[0038] This application discloses a dimming device.

[0039] It should be noted that, in the description of this invention, the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention 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. Therefore, they should not be construed as limitations on this invention.

[0040] Example 1: Refer to Figure 1 and Figure 2 A dimming device includes a transparent sealing module 1 and multiple microstructure modules 2. The transparent sealing module 1 has a receiving cavity 11, and the multiple microstructure modules 2 are arranged in an array in the receiving cavity 11, thereby enabling the dimming device to effectively adjust the light passing through.

[0041] The transparent sealing module 1 includes a transparent substrate 12 and a transparent cover layer 13. The transparent cover layer 13 is disposed above the transparent substrate 12, and the edge of the transparent cover layer 13 is sealed to the edge of the transparent substrate 12, so that a sealed receiving cavity 11 is formed between the transparent cover layer 13 and the transparent substrate 12.

[0042] In this embodiment, the transparent substrate 12 is a transparent glass substrate or a transparent polymer substrate, and the transparent cover layer 13 is made of transparent glass or a transparent polymer film. The thickness of the transparent substrate 12 is 0.5-1.0 mm, and the thickness of the transparent cover layer 13 is 0.3-1.0 mm. The transparent cover layer 13 and the transparent substrate 12 are sealed together by anodic bonding or UV-curable adhesive.

[0043] The cavity 11 is filled with an inert gas (such as argon or nitrogen) at a pressure of 50-100 kPa to prevent the microstructure module 2 from being corroded by moisture, dust and other factors in the external environment. The height of the cavity 11 (i.e., the distance between the transparent cover layer 13 and the transparent substrate 12) is 100-150 μm.

[0044] A conductive layer 14 is disposed on the side of the transparent substrate 12 near the transparent capping layer 13. In this embodiment, the conductive layer 14 is made of a transparent conductive oxide, such as indium tin oxide (ITO) or aluminum zinc oxide (AZO), preferably indium tin oxide (ITO), with a thickness of 100-300 nm. The conductive layer 14 is patterned into multiple independent bottom electrodes through photolithography and etching processes. The multiple bottom electrodes are arranged in an array on the transparent substrate 12.

[0045] A transparent conductive oxide layer is sputtered on the side of the transparent capping layer 13 near the conductive layer 14 as a top electrode, and the ITO layer thickness is 50-200 nm. The top electrode can be a full-surface electrode covering the inner surface of the transparent capping layer 13, or it can be patterned into multiple independent electrodes corresponding to the bottom electrode.

[0046] Multiple microstructure modules 2 are arranged in an array along the row and column directions, and each microstructure module 2 corresponds to a bottom electrode. The multiple microstructure modules 2 cooperate with each other to achieve full coverage control of the light transmission area of ​​the entire dimming device.

[0047] Reference Figure 2 and Figure 3 The microstructure module 2 includes a dimming unit 21 and a stabilization unit 22. The dimming unit 21 is a thin sheet structure with a certain thickness, and its shape can be one of rectangle, trapezoid, triangle or circle, preferably rectangular. The dimensions of the dimming unit 21 are 50-100 micrometers in length, 10-20 micrometers in width, and 400-800 nanometers in thickness. In this embodiment, it is preferably 100 micrometers in length, 20 micrometers in width, and 500 nanometers in thickness.

[0048] The dimming unit 21 is made of polycrystalline silicon or silicon nitride. When the dimming unit 21 is made of polycrystalline silicon, the polycrystalline silicon is treated with phosphorus doping or boron doping to form heavily doped polycrystalline silicon, with a doping concentration of 10. 18 Up to 10 20 cm -3 This improves the light-shielding performance of the dimming unit 21, reducing the transmittance to less than 1% under the light-shielding state. Within the above doping concentration range, the absorption coefficient of the polycrystalline silicon film in the visible light band (400-700nm) is significantly increased, and the transmittance of the heavily doped polycrystalline silicon film with a thickness of 400-800nm ​​can be reduced to less than 1% for visible light.

[0049] In this embodiment, anchor points 15 are provided on the conductive layer 14. Anchor points 15 are fixed support areas formed by the rigid connection between the structural layer 17 and the conductive layer 14 through anchoring holes. The dimming unit 21 is connected to the anchor points 15 through a pair of torsion hinge beams. The torsion hinge beams are thin, elongated polycrystalline silicon beams in the same layer as the dimming unit 21, with a width of 0.2-0.8 μm, a length of 40-80 μm, and a thickness the same as the structural layer 17. The two torsion hinge beams are collinearly arranged along one short side of the dimming unit 21. One end of each torsion hinge beam is integrally connected to the anchor point 15, and the other end is integrally connected to the edge of the dimming unit 21. All three are formed in the same patterning process. When the dimming unit 21 is flipped, the torsion hinge beams undergo elastic torsional deformation, allowing the dimming unit 21 to deflect 80°-90° around its axis. The other end of the dimming unit 21 is a free end.

[0050] The bottom electrode is located directly below the dimming unit 21. In the light-shielding position, the dimming unit 21 is close to the surface of the conductive layer 14. In the light-transmitting position, the dimming unit 21 is raised, and the entire dimming unit 21 is nearly perpendicular to the plane of the transparent substrate 12, with an angle of 80° to 90°, preferably 85°, with the surface of the transparent substrate 12. The height of the receiving cavity 11 is greater than the length of the dimming unit 21 to ensure that the dimming unit 21 does not mechanically interfere with the transparent cover layer 13 when it is flipped. For example, when the length of the dimming unit 21 is 100 μm, the height of the receiving cavity 11 is selected to be 100 to 150 μm.

[0051] In this embodiment, the dimming units 21 in adjacent rows are staggered along the column direction. When the dimming unit 21 is in the light-blocking position, the edges of two adjacent dimming units 21 in the same row overlap each other, and the area of ​​the overlapping part accounts for 10% to 15% of the surface area of ​​a single dimming unit 21, ensuring no light leakage gaps. When the dimming unit 21 is in the light-transmitting position, a light-transmitting gap is formed between adjacent dimming units 21 to allow light to pass through.

[0052] Reference Figure 1 and Figure 3 The dimming device also includes a drive module 3. The leads of the bottom electrode and the top electrode are led out from the edge of the transparent sealing module 1 and electrically connected to the drive module 3 via a flexible circuit board. In this embodiment, the drive module 3 uses a pulse generator to apply voltage pulses between the bottom electrode and the top electrode, thereby driving the dimming unit 21 to switch between light-transmitting and light-blocking positions.

[0053] The pulse voltage output by the drive module 3 has an amplitude of 30-80V, preferably 50V; a pulse width of 0.5-2ms, preferably 1ms; and a pulse waveform of rectangular or trapezoidal wave. The above voltage range is applicable to dimming unit 21 with a length of 50-100μm and a distance of 1-3μm between the bottom electrode and dimming unit 21.

[0054] When a voltage pulse is applied between the top electrode and the dimming unit 21, electrostatic attraction pulls the free end of the dimming unit 21 upwards to the light-transmitting position; when a voltage pulse is applied between the bottom electrode and the dimming unit 21, electrostatic attraction pulls the free end of the dimming unit 21 downwards to the light-blocking position. After the pulse ends, the voltage on the electrode returns to zero, and the dimming unit 21 is maintained in its current position by the mechanical locking force of the stabilization unit 22.

[0055] In this embodiment, two anchor points 15 are provided, and the stabilization unit 22 includes a buckling beam 221 and a flexible linkage arm 222. The buckling beam 221 is a slender polycrystalline silicon beam with a width of 2-5 μm and a thickness of 400-800 nm, and both ends of the buckling beam 221 are fixed to the two anchor points 15 respectively. The two anchor points 15 are arranged along the short side direction of the dimming unit 21, and the buckling beam 221 extends along the short side direction of the dimming unit 21. The length of the buckling beam 221 is slightly greater than the straight-line distance between the two anchor points 15 (the length difference is 0.1% to 1% of the distance between the anchor points 15), so that the buckling beam 221 is in an axially compressed state and has two steady-state buckling directions: upward buckling and downward buckling.

[0056] It should be noted that the buckling displacement at the midpoint of the buckling beam 221 is 1-5 μm, and the lowest position of the midpoint of the buckling beam 221 will not contact the surface of the conductive layer 14 when it arches downward.

[0057] Reference Figure 2 and Figure 3 The flexible linkage arm 222 is a polycrystalline silicon thin-film structure with elastic deformation capability, with a width of 1-3 μm, and is fabricated in the same layer as the dimming unit 21. One end of the flexible linkage arm 222 is connected to the middle of the buckling beam 221, and the other end is connected to the force point on the dimming unit 21 near the flip axis. The distance between the force point and the flip axis is 1-10 μm, which is much smaller than the total length of the dimming unit 21, thus forming a lever structure.

[0058] When the dimming unit 21 flips under electrostatic force, the out-of-plane displacement generated at the force point is transmitted to the middle of the buckling beam 221 through the flexible linkage arm 222, causing the buckling beam 221 to jump from one steady-state buckling direction to another, thereby achieving bistable locking of the dimming unit 21. During this process, the flexible linkage arm 222 adapts to the difference in motion trajectory at both ends through its own elastic bending.

[0059] When the dimming unit 21 is in the light-blocking position, the buckling beam 221 arches downwards, and the flexible linkage arm 222 presses the dimming unit 21 toward the transparent substrate 12, so that the dimming unit 21 is close to the transparent substrate 12.

[0060] The implementation principle of a dimming device in this application embodiment is as follows: When it is necessary to make the dimming device transparent, the driving module 3 applies a pulse to the top electrode. The electrostatic attraction pulls the free end of the dimming unit 21 upward. The flexible linkage arm 222 drives the midpoint of the buckling beam 221 to move upward. After the buckling beam 221 passes the unstable equilibrium position in the middle, it quickly flips to the upward arched state under the action of its own elastic force. The flexible linkage arm 222 pushes the dimming unit 21 to the light-transmitting position.

[0061] When the dimming device needs to be shielded, the drive module 3 applies a voltage pulse to the bottom electrode, generating an electrostatic attraction between the bottom electrode and the free end of the dimming unit 21, pulling the free end downward. The downward movement of the free end causes the flexible linkage arm 222 to rotate the buckling beam 221 to a downward arched state, and the flexible linkage arm 222 presses the dimming unit 21 back to the shielded position.

[0062] In another preferred embodiment, the bottom and top electrodes may be omitted. Instead, an electromagnetic coil is positioned on the side of the transparent substrate 12 opposite to the dimming unit 21, and a hard magnetic thin film layer with a permanent magnetic moment is disposed on the dimming unit 21, the direction of which is perpendicular to the surface of the dimming unit 21. A pulsed magnetic field is generated by the electromagnetic coil, thereby driving the dimming unit 21 to flip, thus switching the dimming unit 21 between a light-blocking and light-transmitting position. In this embodiment, the anchor point 15 is disposed on the transparent substrate 12.

[0063] Example 2: Refer to Figure 4 The difference between this embodiment and embodiment 1 is that the stabilization unit 22 is different.

[0064] In this embodiment, the dimming unit 21 is connected to the anchor point 15 via a torsion hinge beam, the structure of which is the same as in embodiment 1. The "rotation axis" referred to in this embodiment is the flip axis defined by the common axis of the two torsion hinge beams. The rotation of the dimming unit 21 is achieved through the elastic torsional deformation of the torsion hinge beam.

[0065] Reference Figure 2 and Figure 4 The stabilization unit 22 includes a guide rail 223, a slider 224, and a Z-shaped hinge 225. The guide rail 223 is made of the same structural layer material (polycrystalline silicon) as the dimming unit 21, and is fixed to the surface of the conductive layer 14. Each end of the guide rail 223 has a locking structure 2231. The locking structure 2231 is a locking recess, and the depth of the recess is 0.5-2 μm deeper than the main body of the guide rail 223.

[0066] The slider 224 is slidably mounted on the guide rail 223. In this embodiment, the cross-section of the connection between the slider 224 and the guide rail 223 can be T-shaped, dovetail-shaped, or U-shaped to prevent the slider 224 from easily detaching from the guide rail 223. When the slider 224 slides to the locking structure 2231 at both ends of the guide rail 223, the locking structure 2231 locks the slider 224, forming two stable locking positions.

[0067] In other embodiments, the locking structure 2231 can also be configured as an elastic stop. The elastic stop is a cantilever beam structure fixed to the inner wall of the guide rail 223. Two elastic stops are arranged opposite each other, and the distance between the two elastic stops is slightly smaller than the width of the slider 224. When the slider 224 slides to the elastic stop under the action of the driving force, the slider 224 pushes open the two elastic stops to pass through. The elastic stops then rebound and clamp the slider 224 from both sides, forming a lock. When unlocking, the reverse driving force overcomes the rebound force of the elastic stops, causing the slider 224 to push open the elastic stops again and disengage. The locking force of the elastic stops is controlled by adjusting the length and thickness of the cantilever beam.

[0068] The Z-type hinge 225 is a polycrystalline silicon sheet spring bent in a "Z" shape, having two parallel horizontal arms and a diagonal arm connecting the two arms. One end of the Z-type hinge 225 is connected to the free end of the dimming unit 21, and the other end is connected to the slider 224.

[0069] The Z-shaped hinge 225 converts the rotational motion of the dimming unit 21 into the linear motion of the slider 224. The principle of this motion conversion is as follows: when the dimming unit 21 rotates around its axis, the arc motion of the free end of the dimming unit 21 generates a component force along the guide rail 223 through the inclined arm of the Z-shaped hinge 225, pushing the slider 224 to slide linearly along the guide rail 223. The bending structure of the Z-shaped hinge 225 adapts to the kinematic difference between rotational and linear motion during the movement by the relative rotation of each arm. When the dimming unit 21 is in the light-shielding position, the slider 224 is located in the locking recess near the axis, the Z-shaped hinge 225 is in a folded state, and the dimming unit 21 is close to the transparent substrate 12, in the light-shielding position.

[0070] The implementation principle of Example 2 is as follows: When it is necessary for the dimming device to transmit light, when the driving module 3 applies a voltage pulse to the top electrode, the free end of the dimming unit 21 is subjected to an upward electrostatic attraction and begins to rotate around the axis. The rotation of the dimming unit 21 drives the slider 224 to slide along the guide rail 223 from the end near the axis to the end away from the axis through the Z-shaped hinge 225. The Z-shaped hinge 225 gradually unfolds from the folded state, and its elastic restoring force helps to push the dimming unit 21 to continue rotating. When the slider 224 slides into the locking recess at the end away from the axis, it is locked, and the dimming unit 21 enters the light-transmitting position.

[0071] When the dimming device needs to be shielded, the drive module 3 applies a voltage pulse to the bottom electrode, causing the free end of the dimming unit 21 to be subjected to a downward electrostatic attraction and begin to rotate in the opposite direction. The slider 224 disengages from the distal locking recess and slides along the guide rail 223 toward the end near the rotating shaft, while the Z-shaped hinge 225 gradually folds from the unfolded state. When the slider 224 slides into the locking recess near the rotating shaft, it is locked, and the dimming unit 21 returns to the shielded position.

[0072] This application also discloses a method for fabricating a dimming device.

[0073] Reference Figure 5 and Figure 6 A method for fabricating a dimming device includes the following steps: S1: A transparent substrate 12 is provided, which is made of high optical quality, smooth surface, double-sided polished glass, or high-temperature resistant polymer. A transparent conductive layer 14 is deposited on the transparent substrate 12. The material of the conductive layer 14 is a transparent conductive oxide, preferably indium tin oxide (ITO), with a thickness of 100-300 nm. The conductive layer 14 is patterned using photolithography and etching processes to form multiple bottom electrodes and common leads arranged in an array. Each bottom electrode corresponds to a dimming unit 21.

[0074] S2: A sacrificial layer 16 is deposited on the conductive layer 14, covering the bottom electrode. The sacrificial layer 16 is made of silicon dioxide and has a thickness of 1-3 micrometers. This thickness determines the gap height between the dimming unit 21 and the transparent substrate 12 after release, i.e., the flipping space of the dimming unit 21. Anchoring holes are formed in the sacrificial layer 16 through photolithography and etching processes. These anchoring holes are used to define the anchor point 15 region of the microstructure module 2.

[0075] S3: Deposit a structural layer 17 on the sacrificial layer 16 and within the anchoring holes. A structural layer 17 of uniform thickness is deposited on the sacrificial layer 16 by low-pressure chemical vapor deposition (LPCVD). The structural layer 17 is made of one of doped polycrystalline silicon, amorphous silicon, or silicon nitride, with a thickness of 400-800 nm, preferably 500 nm, and a deposition temperature of 580-650 °C. When polycrystalline silicon is used, phosphorus or boron ion implantation doping is performed during or after deposition, with a doping concentration of 10. 18 -10 20 cm -3 .

[0076] Reference Figure 2 and Figure 3 S4: Photoresist is coated on the structural layer 17, and the pattern of the microstructure module 2 is transferred onto the photoresist by photolithography. The pattern of the microstructure module 2 includes the outline of the dimming unit 21, the shape of the stabilization unit 22, and the position of the anchoring hole.

[0077] It should be noted that, for Embodiment 1, the pattern of the stabilization unit 22 includes the arc-shaped pattern of the buckling beam 221 and the pattern of the flexible linkage arm 222. The two ends of the arc-shaped pattern of the buckling beam 221 are aligned with two anchor holes, and the arc length of the arc-shaped pattern is greater than the straight-line distance between the two anchor holes. The pattern of the flexible linkage arm 222 connects the middle of the arc-shaped pattern of the buckling beam 221 with the stress point on the pattern of the dimming unit 21 near the anchor point.

[0078] In embodiment 2, the pattern of the stabilization unit 22 includes a guide rail pattern 223, a slider pattern 224, and a Z-shaped hinge pattern 225. The slider pattern 224 is located on the guide rail 223 and is not connected to any anchoring hole. The Z-shaped hinge pattern 225 connects the free end of the dimming unit 21 pattern to the slider pattern 224.

[0079] The pattern of the stabilization unit 22 in Embodiment 1 is used as an example below.

[0080] The structural layer 17 is patterned using photolithography and etching processes to form the patterns of the dimming unit 21 and the stabilizing unit 22. The etching method is preferably reactive ion etching (RIE) or deep reactive ion etching (DRIE), with an etching selectivity ratio (structural layer 17: sacrificial layer 16) greater than 10:1. At this point, the structural layer 17 within the anchoring holes is directly deposited onto the conductive layer 14 to form anchor points 15, which are rigidly connected to the conductive layer 14. The dimming unit 21 is integrally connected to the anchor point 15 via a torsion hinge beam, the pattern of which is formed simultaneously with the pattern of the dimming unit 21 in this step. The flipping motion of the dimming unit 21 is achieved through the elastic torsional deformation of the torsion hinge beam.

[0081] It should be noted that during the deposition stage of structural layer 17, buckling beam 221 is attached to the surface of sacrificial layer 16 along with structural layer 17, existing in a planar bending form; when sacrificial layer 16 is removed in step S5, the two ends of buckling beam 221 are constrained by anchor points 15. Since the arc length is greater than the spacing of anchor points 15, buckling beam 221 is in an axially compressed state. Under the combined action of residual stress and compressive load, buckling beam 221 changes from a planar bending form to an out-of-plane buckling form, automatically entering a steady-state buckling position of upward or downward arching.

[0082] S5: Remove the sacrificial layer 16, releasing the patterns of the dimming unit 21 and the stabilizing unit 22 into a suspended state. Specifically, the silicon dioxide sacrificial layer 16 is removed using a hydrofluoric acid vapor etching process, or the entire structure is immersed in an etchant to selectively etch and remove the silicon dioxide sacrificial layer 16. The etchant is a 49% hydrofluoric acid aqueous solution or a buffered oxide etchant. The etchant enters below the sacrificial layer 16 through the anchoring holes for etching; the sacrificial layer 16 below the microstructure is completely etched away, forming a suspended and movable structure; the structural layer 17 at the anchoring hole location directly contacts and is fixed to the conductive layer 14, forming anchor points 15. At this time, the dimming unit 21 and the stabilizing unit 22 are respectively connected to the anchor points 15, and the dimming unit 21 can rotate around its connection with the anchor point 15, with the dimming unit 21 located above the bottom electrode. At this time, the stabilizing unit 22 is actuated to enter the initial steady-state position due to the release of residual stress in the structural layer 17 after the removal of the sacrificial layer 16.

[0083] After release, the microstructure module 2 array was subjected to supercritical point drying (using supercritical CO2). 2 To prevent surface tension from causing structural adhesion and failure, a self-assembled monolayer (such as perfluorodecyltrichlorosilane) is deposited on the surface of the released microstructure as an anti-adhesion coating to reduce surface adhesion between microstructures and between the microstructure and the transparent substrate 12.

[0084] S6: A transparent cover layer 13 is provided, which is made of glass and has a thickness of 0.3-1.0 mm. A top electrode material layer is deposited on one side surface of the transparent cover layer 13, and the top electrode material layer is patterned by photolithography and etching processes to form the top electrode. The transparent cover layer 13 and the transparent substrate 12 are sealed and connected in a vacuum or inert gas environment, so that the top electrode faces the dimming unit 21, and a sealed receiving cavity 11 is formed between the transparent cover layer 13 and the transparent substrate 12. Anodal bonding or UV-curable adhesive is used for sealing. The inert gas is argon or nitrogen, and the pressure inside the receiving cavity 11 is 50-100 kPa; the vacuum degree is preferably 1×10⁻⁶ in a vacuum environment. -1 -1×10 -3 Pa. The spacing between the transparent cover layer 13 and the transparent substrate 12 is 100-150 micrometers, which is greater than the maximum height of the dimming unit 21 when it is erected in the light-transmitting position. The dimming unit 21, the stabilization unit 22, the bottom electrode, and the top electrode are all encapsulated within the receiving cavity 11.

[0085] S7: The electrode leads on the transparent substrate 12 and the transparent cover layer 13 are connected to the flexible circuit board by thermo-press bonding with anisotropic conductive adhesive to form an electrical interface. The electrical interface includes row / column addressing lines of the bottom electrode, top electrode leads, and ground lines.

[0086] This application also discloses an anti-reflective signal light.

[0087] Reference Figure 2 and Figure 7 An anti-reflective signal light includes a signal light body 4 and a dimming device as described in Embodiment 1 or Embodiment 2 above.

[0088] The main body 4 of the signal light includes a lamp housing 41, a light-emitting bowl 42, a light source 43, and a control circuit board. The lamp housing 41 has a light outlet 411 at its front end, and a transparent front cover 412 is provided at the light outlet 411. The light-emitting bowl 42 is disposed inside the lamp housing 41 and faces the light outlet 411, and the light source 43 is located at the bottom center of the light-emitting bowl 42. In this embodiment, the light source 43 is an LED lamp bead.

[0089] The dimming device is disposed at and covers the light outlet 411. Specifically, the dimming device is attached to the inner surface of the transparent front cover 412 using optically transparent adhesive (OCA), with the transparent cover layer 13 of the dimming device facing the transparent front cover 412 and the transparent substrate 12 facing the inside of the lamp housing 41. In other embodiments, the connection between the dimming device and the transparent front cover 412 can also be a snap-fit ​​connection or a bolt connection.

[0090] The control circuit board is housed within the lamp housing 41 and electrically connected to the lamp source 43 and the dimming device. Specifically, the control circuit board is electrically connected to the LED of the lamp source 43 and the dimming device. The control circuit board is used to switch the dimming unit 21 to the light-transmitting position before the lamp source 43 is turned on, and to switch the dimming unit 21 to the light-shielding position after the lamp source 43 is turned off. The specific control timing is as follows: Reference Figure 1 and Figure 7 When the signal light is turned on: After receiving the "turn on" command, the control circuit board first sends an "on" signal to the drive module 3. The drive module 3 applies an on pulse to the dimming device, driving the dimming device to flip from the light-blocking position to the light-transmitting position. After confirming that the dimming device has switched (delay 5-15ms), the control circuit board then connects the power supply circuit of the light source 43 to turn on the light source 43.

[0091] When the indicator light is turned off: After receiving the "turn off" command, the control circuit board first turns off the light source 43; after confirming that the light source 43 is turned off (delay 5-15ms), it sends a "turn off" signal to the drive module 3. The drive module 3 applies a turn-off pulse to the dimming device, driving the dimming device to flip from the light-transmitting position to the light-blocking position.

[0092] This timing design ensures that at any given moment, the traffic light is either in a safe state where the dimmer is off and light source 43 is off, or in a normal working state where the dimmer is on and light source 43 is off, avoiding the window of opportunity where the dimmer is on and light source 43 is off. During the extinguishing process, light source 43 is extinguished first, and then the dimmer is switched to the off position. Since light source 43 is already off, even if the dimmer has not yet completed the off-light switching, the traffic light will not produce any signal display, ensuring safety.

[0093] The implementation principle of this embodiment is as follows: The anti-reflective signal light uses a dimming device installed at the light outlet 411, and the control circuit board coordinates the operation of the dimming device and the light source 43. When the signal light is off, the dimming device is in a light-blocking state, physically isolating external sunlight reflected light from entering the lamp cavity and eliminating false brightness; when the signal light is on, the dimming device is in a light-transmitting state, and the light emitted by the light source 43 is transmitted normally. The bistable structure of the dimming device allows it to maintain its state without continuous power supply after switching.

[0094] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A dimming device, characterized in that, include: A transparent sealing module (1) is provided with a receiving cavity (11). Multiple microstructure modules (2) are provided, and the multiple microstructure modules (2) are arranged in an array in the receiving cavity (11). Each microstructure module (2) includes a dimming unit (21) and a stabilization unit (22) connected to the dimming unit (21). One end of the dimming unit (21) is rotatably disposed in the receiving cavity (11), and the other end of the dimming unit (21) is a free end, so that the dimming unit (21) can be flipped to have light-transmitting and light-shielding positions. When the dimming unit (21) is in the light-transmitting position, a light-transmitting gap is formed between adjacent dimming units (21) to allow light to pass through. When the dimming unit (21) is in the light-blocking position, the edges of adjacent dimming units (21) overlap each other to block the light passing through the transparent sealing module (1). The stabilizing unit (22) has two stable equilibrium positions, which correspond to the light-transmitting and light-blocking positions respectively, so as to lock the dimming unit (21) in the light-transmitting or light-blocking position when there is no power supply.

2. The dimming device according to claim 1, characterized in that: It also includes a drive module (3), the transparent sealing module (1) includes a transparent substrate (12) and a transparent cover layer (13) sealed to the transparent substrate (12), the receiving cavity (11) is formed between the transparent substrate (12) and the transparent cover layer (13), a conductive layer (14) is provided on the side of the transparent substrate (12) near the transparent cover layer (13), a plurality of dimming units (21) are arranged in an array on the conductive layer (14), and one end of the dimming unit (21) is rotatably disposed on the conductive layer (14). The conductive layer (14) includes multiple independent bottom electrodes, which are arranged one-to-one with the dimming unit (21). The transparent cover layer (13) has a top electrode on the side close to the conductive layer (14). The bottom electrode and the top electrode are electrically connected to the driving module (3). The driving module (3) is used to apply a voltage pulse between the bottom electrode and the top electrode to drive the dimming unit (21) to switch between light-transmitting and light-blocking positions.

3. The dimming device according to claim 2, characterized in that: Two anchor points (15) are provided on the conductive layer (14). The dimming unit (21) is rotatably connected to the two anchor points (15) respectively. The stabilization unit (22) includes a buckling beam (221) and a flexible linkage arm (222). The two ends of the buckling beam (221) are fixed on the two anchor points (15) respectively. The length of the buckling beam (221) is greater than the straight distance between the two anchor points (15) so that the buckling beam (221) is in an axially compressed state and has two stable buckling directions of upward and downward arching. One end of the flexible linkage arm (222) is located in the middle of the buckling beam (221), and the other end of the flexible linkage arm (222) is connected to the dimming unit (21).

4. The dimming device according to claim 2, characterized in that: Anchor points (15) are provided on the conductive layer (14). The dimming unit (21) is rotatably connected to the anchor points (15). The stabilization unit (22) includes a guide rail (223), a sliding member (224), and a Z-shaped hinge (225). The guide rail (223) is provided on the inner wall of the receiving cavity (11). The two ends of the guide rail (223) are respectively provided with locking structures (2231). The sliding member (224) is slidably disposed on the guide rail (223). When the sliding member (224) slides to the locking structure (2231), the locking structure (2231) locks with the sliding member (224). One end of the Z-shaped hinge (225) is connected to the dimming unit (21), and the other end of the Z-shaped hinge (225) is connected to the sliding member (224).

5. The dimming device according to claim 1, characterized in that: Multiple microstructure modules (2) are arranged in an array along the row and column directions. When the dimming unit (21) is in the light-shielding position, the edges of two adjacent dimming units (21) in the same row overlap each other, and the area of ​​the overlapping part accounts for 10%-15% of the surface area of ​​a single dimming unit (21).

6. A method for fabricating a dimming device, characterized in that, Includes the following steps: S1: Provide a transparent substrate (12), deposit a transparent conductive layer (14) on the transparent substrate (12), and pattern the conductive layer (14) using photolithography and etching processes to form multiple bottom electrodes arranged in an array; S2: Deposit a sacrificial layer (16) on the conductive layer (14), the sacrificial layer (16) covering the bottom electrode, and form an anchoring hole through the sacrificial layer (16) by photolithography and etching processes; S3: Deposit a structural layer (17) on the sacrificial layer (16) and inside the anchoring hole; S4: The structural layer (17) is patterned by photolithography and etching processes to form a dimming unit (21) pattern and a stabilization unit (22) pattern; S5: Remove the sacrificial layer (16) to release the dimming unit (21) pattern and the stabilization unit (22) pattern from the sacrificial layer (16) and into a suspended state; S6: Provide a transparent cover layer (13), deposit a top electrode material layer on one side surface of the transparent cover layer (13), pattern the top electrode material layer by photolithography and etching process to form a top electrode, then seal the transparent cover layer (13) to the transparent substrate (12) so that the top electrode faces the dimming unit (21), and form a sealed receiving cavity (11) between the transparent cover layer (13) and the transparent substrate (12), the dimming unit (21), the stabilization unit (22), the bottom electrode and the top electrode are all encapsulated in the receiving cavity (11).

7. The method for preparing the dimming device according to claim 6, characterized in that: The material of the sacrificial layer (16) is silicon dioxide, and the material of the structural layer (17) is one of doped polycrystalline silicon, amorphous silicon and silicon nitride. In S5, the sacrificial layer (16) is removed by hydrofluoric acid vapor etching process.

8. The method for preparing a dimming device according to claim 6, characterized in that: It also includes step S7: connecting the electrode leads on the transparent substrate (12) and the transparent cover layer (13) to the flexible circuit board by thermo-press bonding with anisotropic conductive adhesive to form an electrical interface.

9. A light-reflecting signal light, characterized in that: The signal light body (4) includes a dimming device as described in any one of claims 1-5. The signal light body (4) has a light outlet (411) and the dimming device is disposed at the light outlet (411) and covers the light outlet (411).

10. The anti-reflective signal light according to claim 9, characterized in that: The main body (4) of the signal light includes a lamp housing (41), a light-emitting bowl (42), a light source (43), and a control circuit board. The light outlet (411) is located at the front end of the lamp housing (41). The light-emitting bowl (42) is located inside the lamp housing (41) and faces the light outlet (411). The light source (43) is located at the bottom center of the light-emitting bowl (42). The control circuit board is located inside the lamp housing (41) and is electrically connected to the light source (43) and the dimming device, respectively.

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