A projectable bicycle light

Abstract

The application discloses a projectable bicycle lamp, which comprises a lamp shell, a light source module, a projection optical module, a posture detection unit, a first optical adjusting element, a second optical adjusting element and a control unit. The posture detection unit is used for detecting the inclination angle of the bicycle and outputting an inclination angle signal. The control unit controls the first optical adjusting element to switch between a first state and a second state according to the inclination angle signal, and controls the second optical adjusting element to switch between a third state and a fourth state. When the bicycle is upright, the projection optical module projects a predetermined pattern at a first exit angle; when the bicycle is inclined to turn, the projection optical module projects the predetermined pattern at a second exit angle, and the second exit angle is configured to compensate for the stretching distortion and position deviation of the predetermined pattern on the road surface caused by the inclination of the bicycle. The application can simultaneously maintain the position stability and shape fidelity of the projected pattern when the bicycle is inclined to turn through the linkage compensation of the double optical elements.

Description

Technical Field

[0001] This application relates to the field of bicycle technology, and more specifically to a projectable bicycle light. Background Technology

[0002] As a green and environmentally friendly mode of transportation, bicycles require lights to warn surrounding vehicles and pedestrians when ridden at night or in low visibility conditions to ensure riding safety. In recent years, bicycle lights with road projection functions have gradually gained attention. They can project warning patterns onto the road surface, effectively expanding the warning range and improving the warning effect. However, when a bicycle turns, the bicycle body tilts, causing the emission angle of the projection light mounted on the bicycle body relative to the road surface to change. This results in stretching distortion and positional shift of the warning pattern projected onto the road surface, thereby reducing the recognizability and warning effect of the warning pattern. In the prior art, such as Chinese invention patent CN113844575B (a bicycle taillight with adaptive projection angle adjustment), a bicycle taillight is disclosed. It is equipped with a posture adjustment device, on which the projection light is mounted. The posture adjustment device can rotate the projection light as a whole according to the tilt angle of the bicycle to adjust the emission angle, thereby avoiding significant changes in the projected pattern when the vehicle turns. However, this solution only uses a single overall rotation adjustment method to "coarsely adjust" the light output angle of the projection lamp. Although it can improve the positional offset of the projected pattern to some extent, it cannot adjust the light path inside the projection beam in segments. Therefore, it is difficult to effectively compensate for the stretching distortion of the projected pattern, and the shape fidelity of the projected pattern still needs to be improved. Summary of the Invention

[0003] In view of this, the present disclosure provides a projectable bicycle light that at least partially solves the problems existing in the prior art.

[0004] An invention relates to a projectable bicycle light, comprising: The lamp housing is mounted on the bicycle frame; A light source module is disposed inside the lamp housing and is used to emit illumination light and / or projection light; A projection optical module is disposed inside the lamp housing and located in the light output path of the light source module, and is used to form the light emitted by the light source module into a projection beam with a predetermined pattern and project it onto the road surface. An attitude detection unit is disposed inside the lamp housing or on the bicycle frame, and is used to detect the tilt angle of the bicycle and output a tilt angle signal; A first optical adjustment element is disposed in the optical path between the light source module and the projection optical module, and the first optical adjustment element has a first state and a second state. A second optical adjustment element is disposed on the light-emitting side of the projection optical module, and the second optical adjustment element has a third state and a fourth state. The control unit is electrically connected to the attitude detection unit, the first optical adjustment element, and the second optical adjustment element, respectively. When the bicycle is in an upright position, the posture detection unit outputs a first tilt angle signal, the control unit controls the first optical adjustment element to remain in the first state and controls the second optical adjustment element to remain in the third state according to the first tilt angle signal, and the projection optical module projects the predetermined pattern at a first emission angle. When the bicycle is in a tilted turning state, the attitude detection unit outputs a second tilt angle signal, and the control unit controls the first optical adjustment element to switch to the second state and controls the second optical adjustment element to switch to the fourth state according to the second tilt angle signal. The projection optical module projects the predetermined pattern at a second emission angle. The first emission angle is different from the second emission angle, and the second emission angle is configured to compensate for the stretching distortion and / or positional shift of the predetermined pattern on the road surface caused by the bicycle tilt.

[0005] Preferably, the first optical adjustment element includes a first lens bracket rotatably disposed within the lamp housing and a first compensation lens mounted on the first lens bracket; in the first state, the optical axis of the first compensation lens coincides with the light output optical axis of the light source module; in the second state, a first compensation angle is formed between the optical axis of the first compensation lens and the light output optical axis of the light source module.

[0006] Preferably, the second optical adjustment element includes a second lens bracket rotatably disposed within the lamp housing and a second compensation lens mounted on the second lens bracket; in the third state, the optical axis of the second compensation lens coincides with the light output optical axis of the projection optical module; in the fourth state, a second compensation angle is formed between the optical axis of the second compensation lens and the light output optical axis of the projection optical module.

[0007] Preferably, the absolute value of the first compensation angle is greater than the absolute value of the second compensation angle.

[0008] Preferably, the first compensation lens is a negative power lens and the second compensation lens is a positive power lens.

[0009] Preferably, the control unit includes a memory and a processor. The memory stores a tilt angle-compensation angle mapping table. The processor queries the mapping table based on the tilt angle signal output by the attitude detection unit to determine the target state of the first optical adjustment element and the second optical adjustment element.

[0010] Preferably, the tilt angle-compensation angle mapping table stores multiple sets of preset tilt angle values ​​and a first compensation angle value and a second compensation angle value that correspond one-to-one with each preset tilt angle value; the processor matches the corresponding first compensation angle value and the second compensation angle value from the mapping table according to the current tilt angle value corresponding to the tilt angle signal, and controls the first optical adjustment element to rotate the first compensation angle value and controls the second optical adjustment element to rotate the second compensation angle value, respectively.

[0011] Preferably, the attitude detection unit is a MEMS accelerometer or a gyroscope.

[0012] Preferably, the predetermined pattern is at least one of a bicycle icon pattern, a turn arrow pattern, or a safety warning boundary pattern.

[0013] Preferably, the projection optical module includes a condenser lens, a pattern generating element, and a projection lens arranged sequentially along the optical path, wherein the pattern generating element is a fixed pattern sheet or a programmable spatial light modulator.

[0014] The projectable bicycle lamp provided by this invention utilizes two independent adjustable optical elements—a first optical adjustment element and a second optical adjustment element—working collaboratively. Under the control of a control unit, it achieves specific state combinations, switching between the first and third states for an upright position and between the second and fourth states for a tilted position. This achieves the following beneficial effects: In the second state, the first optical adjustment element asymmetrically deflects the passing light beam to change its cross-sectional shape, effectively compensating for the stretching distortion of the projected pattern caused by the bicycle's tilt. In the fourth state, the second optical adjustment element deflects the propagation direction of the light beam to change its projection direction, effectively compensating for the positional shift of the projected pattern caused by the bicycle's tilt. The two optical adjustment elements each have their functional focus and work synergistically in the optical path, jointly achieving dual compensation for both distortion and shift in the projected pattern. Compared to the existing single adjustment method that adjusts the light output angle simply by rotating the entire projection lamp, this invention not only maintains the positional stability of the projected pattern on the road surface but also simultaneously maintains the shape fidelity of the projected pattern. The combined "position + shape" dual fidelity effect has a synergistic effect. In addition, the control unit achieves precise matching between the tilt angle and the compensation angle of the two optical adjustment elements through a tilt angle-compensation angle mapping table. The attitude detection unit uses a MEMS accelerometer or gyroscope, which has the advantages of small size, low power consumption and fast response. The pattern generation element of the projection optical module can project a variety of predetermined patterns as needed to meet the warning requirements of different scenarios. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the exemplary embodiments of this disclosure, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this disclosure and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a cross-sectional view of the present invention; Figure 3 This is an exploded view of the present invention; Figure 4 This is a rear view of the present invention.

[0017] 1. Lamp housing; 2. Light source module; 3. Projection optical module; 31. Condensing lens; 32. Pattern generating element; 33. Projection objective lens; 4. Attitude detection unit; 5. First optical adjustment element; 51. First lens bracket; 52. First compensation lens; 6. Second optical adjustment element; 61. Second lens bracket; 62. Second compensation lens; 7. Control unit; 71. Memory; 72. Processor. Detailed Implementation

[0018] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of this application. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0020] like Figures 1 to 4 As shown, the present invention provides a projectable bicycle light, which is mainly used to be installed on the bicycle body to project a predetermined pattern with warning function onto the road surface at night or in low visibility conditions, and automatically compensate for the stretching distortion and positional offset of the projected pattern when the bicycle tilts and turns.

[0021] like Figure 1 and Figure 2As shown, the projectable bicycle light mainly includes a lamp housing 1, a light source module 2, a projection optical module 3, a posture detection unit 4, a first optical adjustment element 5, a second optical adjustment element 6, and a control unit 7. The lamp housing 1 is generally rectangular in shape and is made of aluminum alloy through die casting, providing good heat dissipation and structural strength. The interior of the lamp housing 1 forms a receiving cavity, which is sequentially divided into a first chamber, a second chamber, and a third chamber along the length of the lamp housing 1. An opening is provided on the rear end face of the lamp housing 1, and a rear cover plate is fixedly connected to this opening by screws. A silicone rubber sealing ring is embedded at the joint surface between the rear cover plate and the lamp housing 1 to prevent rainwater and dust from entering the interior of the lamp housing 1. A light-emitting window is provided on the front end face of the lamp housing 1, and a transparent protective lens is embedded in the light-emitting window. This protective lens is made of optical-grade polymethyl methacrylate material, and its outer periphery is sealed and bonded to the inner wall of the light-emitting window with UV-curable adhesive. The bottom of the lamp housing 1 is equipped with a mounting bracket, which is fixedly connected to the bicycle seatpost or rear top fork by bolts. Several heat dissipation fins are formed on the top wall of the lamp housing 1, arranged parallel to each other along the length of the lamp housing 1, to conduct the heat generated by the light source module 2 to the outside air. Wiring holes are also formed on the side walls of the lamp housing 1, through which power cables and signal cables are threaded. Waterproof sealant is used to fill the space between the wiring holes and the wiring harness.

[0022] like Figure 2 As shown, the light source module 2 is disposed in the first chamber inside the lamp housing 1. The light source module 2 includes an LED light source and a focusing reflector. The LED light source uses a high-power white LED chip with a light-emitting surface size of 2mm×2mm, a rated power of 5W, and a continuous emission wavelength of 450nm to 650nm. The LED chip is attached to an aluminum-based circuit board using thermally conductive silicone grease, and the aluminum-based circuit board is then fixed to the inner wall of the lamp housing 1 with screws. A layer of thermally conductive silicone grease is applied between the aluminum-based circuit board and the inner wall of the lamp housing 1 to ensure that the heat generated by the LED chip can be quickly conducted to the lamp housing 1 and dissipated by the heat sink fins. The focusing reflector is disposed in front of the light emission direction of the LED chip. The focusing reflector is a rotationally symmetrical parabolic reflector with an aluminum reflective film coated on its inner surface, and a reflectivity of not less than 90%. A mounting hole is provided at the bottom of the focusing reflector, and the LED chip is located at the center of the mounting hole, with the light-emitting surface of the LED chip coinciding with the focal point of the focusing reflector. The light source module 2 is used to emit illumination light and projection light, wherein the illumination light is used to illuminate the road surface in front of the bicycle, and the projection light is used to form a projection beam with a predetermined pattern. The light emission axis of the light source module 2 extends along the length direction of the lamp housing 1, that is, along... Figure 2 It extends from left to right.

[0023] like Figure 2As shown, the projection optical module 3 is disposed in the third chamber within the lamp housing 1 and is located on the light output path of the light source module 2. The projection optical module 3 includes a condenser lens 31, a pattern generating element 32, and a projection objective lens 33 arranged sequentially along the light path. The condenser lens 31 is a biconvex spherical lens made of optical-grade polymethyl methacrylate, with a focal length of 15mm and a diameter of 20mm. The condenser lens 31 is fixed to the front end of the third chamber by a first lens retainer, and the optical axis of the condenser lens 31 coincides with the light output optical axis of the light source module 2. The condenser lens 31 is used to converge the divergent light emitted by the light source module 2 into near-parallel light and illuminate the pattern generating element 32. The pattern generating element 32 is disposed behind the condenser lens 31. The pattern generating element 32 is a fixed pattern sheet made of stainless steel sheet through a precision etching process, and has light-transmitting holes on it. The outline of the light-transmitting holes forms the shape of a predetermined pattern. The predetermined pattern is at least one of a bicycle icon pattern, a turn arrow pattern, or a safety warning boundary pattern. In this embodiment, the predetermined pattern is a bicycle icon pattern, and its outline is a side view of a bicycle in motion. The pattern generating element 32 is fixed to the inner wall of the lamp housing 1 by a pattern sheet bracket, and the plane of the pattern generating element 32 is perpendicular to the optical axis of the projection optical module 3. The projection lens 33 is disposed behind the pattern generating element 32. The projection lens 33 is a three-element achromatic lens group, including a first positive lens, a negative lens, and a second positive lens, and the three lenses are cemented together in sequence. The focal length of the projection lens 33 is 25mm, and the numerical aperture is 0.3. It is used to image the pattern light formed by the pattern generating element 32 and project it onto the road surface. The projection lens 33 is fixed to the rear end of the third chamber by a second lens retainer, and the optical axis of the projection lens 33 coincides with the light output optical axis of the light source module 2. In another embodiment, the pattern generating element 32 may also be a programmable spatial light modulator, such as a digital micromirror device, which is electrically connected to the control unit 7 via a flexible cable. The control unit 7 can output different pattern control signals to the digital micromirror device as needed, thereby dynamically changing the predetermined pattern projected onto the road surface.

[0024] like Figure 2 As shown, the attitude detection unit 4 is located in the second chamber inside the lamp housing 1. The attitude detection unit 4 is used to detect the tilt angle of the bicycle and output a tilt angle signal. The attitude detection unit 4 is a MEMS accelerometer, specifically a six-axis motion processing component, model MPU6050, which integrates a three-axis MEMS accelerometer and a three-axis MEMS gyroscope. The MPU6050 chip is surface-mounted onto a printed circuit board, which is fixed to the inner wall of the lamp housing 1 with screws. The power supply pin VDD of the MPU6050 chip is connected to the output of a 3.3V regulated power supply, the ground pin GND is connected to the common ground, and the serial clock pin SCL and serial data pin SDA are respectively connected to the corresponding I / O pins of the control unit 7.2 The C-bus interface pin and the interrupt pin INT are connected to the external interrupt input pin of control unit 7. The MPU6050 chip connects to the I-bus interface pin via I-bus interface INT. 2 The MPU6050 chip exchanges data with the control unit 7 via a C-communication protocol, with a sampling frequency set to 200Hz and a measurement range of ±8g. The MPU6050 chip can detect the bicycle's acceleration and angular velocity in three-dimensional space in real time. The control unit 7 calculates the bicycle's tilt angle relative to the vertical direction by fusing and filtering the acceleration and angular velocity data. In another embodiment, the attitude detection unit 4 can also use an independent single-axis or dual-axis MEMS gyroscope, such as a three-axis analog output gyroscope (e.g., LYPR540AH), whose three-axis analog voltage output terminals are respectively connected to the analog-to-digital converter input pins of the control unit 7. The attitude detection unit 4 can also be located on the bicycle frame instead of inside the lamp housing 1, for example, at the head tube or top tube of the bicycle frame, and electrically connected to the control unit 7 via wires.

[0025] like Figure 2 and Figure 3As shown, the first optical adjustment element 5 is disposed in the optical path between the light source module 2 and the projection optical module 3, specifically at the junction of the second and third chambers within the lamp housing 1. The first optical adjustment element 5 includes a first lens support 51 and a first compensating lens 52. The first lens support 51 is generally annular, with an annular mounting groove for accommodating the first compensating lens 52 on its inner ring. A first rotating shaft and a second rotating shaft protrude from both sides of its outer ring, coaxially arranged and extending horizontally. The first and second rotating shafts are rotatably supported on the inner wall of the lamp housing 1 via first and second bearings, respectively, allowing the first lens support 51 to rotate around a horizontal axis within the lamp housing 1. Both the first and second bearings are miniature rolling bearings, with their inner rings interference-fitted with the first and second rotating shafts, and their outer rings interference-fitted with the inner wall of the lamp housing 1. The outer ring of the first lens support 51 also has a first arc-shaped rack, the extension direction of which is perpendicular to the rotation axis of the first lens support 51. The first arc-shaped rack meshes with the first drive gear mounted on the output shaft of the first stepper motor. The first stepper motor is a two-phase hybrid stepper motor with a step angle of 1.8° and a holding torque of 0.05 N·m. The first stepper motor is fixed to the inner wall of the lamp housing 1 by a motor bracket, and the four-phase winding leads of the first stepper motor are respectively connected to the four output terminals of the first stepper motor driver. The first stepper motor driver uses a micro stepper motor driver chip of model A4988. This driver chip receives control signals from the control unit 7 through its step pulse input pin STEP and direction input pin DIR. The power supply pin of the first stepper motor driver is connected to the 5V power supply output terminal, and its output pins are respectively connected to the four-phase windings of the first stepper motor. The control unit 7 controls the first stepper motor to rotate forward or backward by a specified angle by sending pulse signal quantity and direction signals to the first stepper motor driver. In turn, through the meshing transmission of the first drive gear and the first arc-shaped rack, the first lens bracket 51 is driven to rotate around the horizontal axis to the target angle. The first compensating lens 52 is fixedly installed in the annular mounting groove of the first lens holder 51. The first compensating lens 52 is pressed and fixed by a lens retainer. A rubber buffer gasket is provided between the lens retainer and the inner wall of the annular mounting groove to prevent the first compensating lens 52 from loosening or breaking due to vibration. The first compensating lens 52 is a negative power lens, i.e., a concave lens, made of optical-grade polymethyl methacrylate with a refractive index of 1.491 and an Abbe number of 57.4. Both optical surfaces of the first compensating lens 52 are spherical with radii of curvature of -30mm and -50mm respectively, a center thickness of 2mm, and an effective aperture of 15mm. The optical axis of the first compensating lens 52 intersects perpendicularly with the rotation axis of the first lens holder 51. The first optical adjustment element 5 has a first state and a second state.In the first state, the optical axis of the first compensation lens 52 coincides with the output optical axis of the light source module 2, and the first compensation lens 52 does not deflect the light beam. In the second state, a first compensation angle is formed between the optical axis of the first compensation lens 52 and the output optical axis of the light source module 2, and the first compensation lens 52 deflects the light beam, changing the cross-sectional shape of the light beam.

[0026] like Figure 2 and Figure 3As shown, the second optical adjustment element 6 is disposed on the light-emitting side of the projection optical module 3, that is, behind the projection lens 33 and in front of the light-emitting window of the lamp housing 1. The second optical adjustment element 6 includes a second lens holder 61 and a second compensating lens 62. The second lens holder 61 is generally annular, with an annular mounting groove for accommodating the second compensating lens 62 on its inner ring, and a third rotating shaft and a fourth rotating shaft protruding from both sides of its outer ring, respectively. The third rotating shaft and the fourth rotating shaft are coaxially arranged and extend horizontally. The third rotating shaft and the fourth rotating shaft are rotatably supported on the inner wall of the lamp housing 1 by the third bearing and the fourth bearing, respectively, so that the second lens holder 61 can rotate around the horizontal axis within the lamp housing 1. The third bearing and the fourth bearing are both miniature rolling bearings, with their inner rings interference-fitted with the third rotating shaft and the fourth rotating shaft, and their outer rings interference-fitted with the inner wall of the lamp housing 1. The outer ring of the second lens holder 61 is also provided with a second arc-shaped rack, the extension direction of which is perpendicular to the rotation axis of the second lens holder 61. The second arc-shaped rack meshes with the second drive gear mounted on the output shaft of the second stepper motor. The second stepper motor is a two-phase hybrid stepper motor with a step angle of 1.8° and a holding torque of 0.03 N·m. The second stepper motor is fixed to the inner wall of the lamp housing 1 by a motor bracket, and the four-phase winding leads of the second stepper motor are respectively connected to the four output terminals of the second stepper motor driver. The second stepper motor driver also uses a micro stepper motor driver chip of model A4988. This driver chip receives control signals from the control unit 7 through its step pulse input pin STEP and direction input pin DIR. The control unit 7 controls the second stepper motor to rotate forward or backward by a specified angle by sending pulse signal quantity and direction signals to the second stepper motor driver. In turn, through the meshing transmission of the second drive gear and the second arc-shaped rack, the second lens bracket 61 is driven to rotate around the horizontal axis to the target angle. The second compensating lens 62 is fixedly installed in the annular mounting groove of the second lens bracket 61. The second compensating lens 62 is pressed and fixed by a lens retainer, and a rubber buffer gasket is provided between the lens retainer and the inner wall of the annular mounting groove. The second compensating lens 62 is a positive focal length lens, i.e., a convex lens, made of optical-grade polymethyl methacrylate with a refractive index of 1.491 and an Abbe number of 57.4. Both optical surfaces of the second compensating lens 62 are spherical, with radii of curvature of 40mm and -60mm respectively, a center thickness of 3mm, and an effective aperture of 18mm. The optical axis of the second compensating lens 62 intersects perpendicularly with the rotation axis of the second lens bracket 61. The second optical adjustment element 6 has a third state and a fourth state. In the third state, the optical axis of the second compensating lens 62 coincides with the output optical axis of the projection optical module 3, and at this time, the second compensating lens 62 does not deflect the beam.In the fourth state, a second compensation angle is formed between the optical axis of the second compensation lens 62 and the output optical axis of the projection optical module 3. At this time, the second compensation lens 62 deflects the light beam and changes the projection direction of the light beam.

[0027] like Figure 4 As shown, the control unit 7 is located in the second chamber within the lamp housing 1, behind the attitude detection unit 4. The control unit 7 includes a printed circuit board (PCB) and a memory 71 and a processor 72 integrated on the PCB. The PCB is fixed to the inner wall of the lamp housing 1 with screws. The processor 72 uses a 32-bit ARM Cortex-M3 microcontroller (model STM32F103C8T6) with a clock frequency of 72MHz, 64KB of flash memory, and 20KB of static random access memory. The processor 72's power supply pin VDD is connected to the output of a 3.3V regulated power supply, its ground pin VSS is connected to common ground, and its reset pin NRST is connected to the 3.3V power supply via a 10kΩ pull-up resistor and to common ground via a 0.1μF filter capacitor. The processor 72's I / O pins are... 2The C-bus interface pins PB6 and PB7 are connected to the serial clock pin SCL and serial data pin SDA of the attitude detection unit 4, respectively. The general-purpose input / output pins PA0 to PA3 of the processor 72 are connected to the step pulse input pin STEP and direction input pin DIR of the first and second stepper motor drivers, respectively. The external interrupt input pin PA4 of the processor 72 is connected to the interrupt pin INT of the attitude detection unit 4. The serial communication pins PA9 and PA10 of the processor 72 are connected to an external programming interface for burning the control program. The analog-to-digital converter input pin PA5 of the processor 72 is connected to a power supply voltage detection circuit for monitoring the power supply voltage. The memory 71 consists of a flash memory and a static random access memory (SRAM) packaged in the same chip as the processor 72. The flash memory stores the control program, while the SRAM temporarily stores the tilt angle data output by the attitude detection unit 4 and intermediate variables during the calculation process. The memory 71 also stores a tilt angle-compensation angle mapping table, which stores multiple sets of preset tilt angle values ​​and corresponding first and second compensation angle values. The mapping table's data structure is a two-dimensional array, where each row corresponds to a preset tilt angle value. The first column of the row stores the preset tilt angle value, the second column stores the corresponding first compensation angle value, and the third column stores the corresponding second compensation angle value. The range of preset tilt angle values ​​covers the tilt angle range that a bicycle may experience during actual riding, i.e., 0° to 45°, with a 1° interval between adjacent preset tilt angle values. The first and second compensation angle values ​​corresponding to each preset tilt angle value are predetermined through a combination of theoretical calculation and experimental calibration. Theoretical calculation is based on the principles of geometric optics, calculating the first compensation angle value required to compensate for stretching distortion and the second compensation angle value required to compensate for positional offset based on parameters such as the bicycle tilt angle, the projection distance of the projection optical module 3, and the projection angle. Experimental calibration involves measuring the projected patterns under different tilt angles under actual riding conditions to correct and optimize the theoretical calculation values. The electrical connection relationship between the control unit 7 and the attitude detection unit 4, the first optical adjustment element 5, and the second optical adjustment element 6 is as follows: The processor 72 connects via I... 2 The C-bus receives the tilt angle signal output by the attitude detection unit 4; the processor 72 outputs pulse signals and direction signals to the first stepper motor driver and the second stepper motor driver through the general-purpose input / output pins, thereby controlling the rotation angle and rotation direction of the first stepper motor and the second stepper motor respectively.

[0028] The complete working process of this projectorable bicycle light is as follows: When the bicycle is in an upright position, the tilt angle of the bicycle frame relative to the vertical direction is 0°. The MEMS accelerometer of the attitude detection unit 4 detects the acceleration data of the bicycle frame in real time, and the processor 72 transmits the data through I... 2 The C-bus reads acceleration data at a sampling frequency of 200Hz, filters and calculates the acceleration data, and obtains the current tilt angle value of 0°. The processor 72 queries the tilt angle-compensation angle mapping table stored in the memory 71 based on this tilt angle value, matching the corresponding first compensation angle value of 0° and second compensation angle value of 0°. The processor 72 outputs a low-level signal to the direction input pin DIR of the first stepper motor driver and outputs 0 pulse signals to the step pulse input pin STEP through its general-purpose input / output pins. Based on this, the first stepper motor driver controls the first stepper motor to not rotate, the first lens bracket 51 remains in its initial position, and the optical axis of the first compensation lens 52 coincides with the light output optical axis of the light source module 2, that is, the first optical adjustment element 5 remains in its first state. Simultaneously, the processor 72 outputs a low-level signal to the direction input pin DIR of the second stepper motor driver and outputs 0 pulse signals to the step pulse input pin STEP via its general-purpose input / output pins. The second stepper motor driver controls the second stepper motor to remain stationary, the second lens bracket 61 remains in its initial position, and the optical axis of the second compensation lens 62 coincides with the output optical axis of the projection optical module 3, meaning the second optical adjustment element 6 remains in its third state. At this time, the light emitted from the light source module 2 sequentially passes through the reflection and convergence of the condenser reflector cup, the convergence of the condenser lens 31, the patterning of the pattern generating element 32, the imaging projection of the projection lens 33, the first compensation lens 52 (whose optical axis coincides with the output optical axis and does not deflect the beam), and the second compensation lens 62 (whose optical axis coincides with the output optical axis and does not deflect the beam), finally projecting onto the road surface from the light-emitting window at the first emission angle. Because the bicycle is in an upright position, the angle between the optical axis of the projection optical module 3 and the road surface is the design value, resulting in a complete and accurate pattern projected onto the road surface without stretching distortion or positional offset.

[0029] When the bicycle enters a leaning turning state, such as when turning left, the bicycle body leans to the left at a certain angle relative to the vertical direction, let's say the lean angle is 15°. The MEMS accelerometer of the attitude detection unit 4 detects the change in acceleration of the bicycle body in real time, and the processor 72 transmits the data through I... 2The C-bus reads the acceleration data and calculates the current tilt angle value to be 15°. The processor 72 queries the tilt angle-compensation angle mapping table stored in memory 71 based on this tilt angle value, matching the corresponding first compensation angle value of 8.5° and the second compensation angle value of 3.2°. The processor 72 outputs a high-level signal (indicating forward rotation) to the direction input pin DIR of the first stepper motor driver via its general purpose input / output pins, and outputs N1 pulse signals to the stepper pulse input pin STEP. N1 is calculated based on the step angle of the first stepper motor (1.8°) and the required first compensation angle value of 8.5°, N1 = 8.5° / 1.8° ≈ 4.72. Since the stepper motor uses a 1 / 8 micro-step drive mode, the actual number of output pulses is N1 × 8 ≈ 38 pulses. After receiving the pulse signal, the first stepper motor driver drives the first stepper motor to rotate 8.5° forward. The first stepper motor, through the meshing of the first drive gear and the first arc-shaped rack, drives the first lens bracket 51 to rotate 8.5° around the horizontal axis, thereby forming a first compensation angle of 8.5° between the optical axis of the first compensation lens 52 and the light output optical axis of the light source module 2, that is, the first optical adjustment element 5 switches to the second state. At the same time, the processor 72 outputs a high-level signal (indicating forward rotation) to the direction input pin DIR of the second stepper motor driver through its general-purpose input / output pin, and outputs N2 pulse signals to the step pulse input pin STEP. N2 is calculated based on the step angle of the second stepper motor of 1.8° and the required second compensation angle value of 3.2°, N2 = 3.2° / 1.8° ≈ 1.78. In the 1 / 8 microstep drive mode, the actual number of output pulses is N2 × 8 ≈ 14 pulses. After receiving the pulse signal, the second stepper motor driver drives the second stepper motor to rotate 3.2° forward. Through the meshing of the second drive gear and the second arc-shaped rack, the second stepper motor drives the second lens holder 61 to rotate 3.2° around the horizontal axis, thereby forming a second compensation angle of 3.2° between the optical axis of the second compensation lens 62 and the output optical axis of the projection optical module 3. This means the second optical adjustment element 6 switches to the fourth state. The absolute value of the first compensation angle 8.5° is greater than the absolute value of the second compensation angle 3.2°. At this point, the light emitted by the light source module 2 is sequentially reflected and converged by the condenser reflector cup, converged by the condenser lens 31, patterned by the pattern generating element 32, projected by the projection lens 33, and then passed through the first compensation lens 52 (which forms an 8.5° angle with the output light axis, deflecting the beam and changing its cross-sectional shape to compensate for stretching distortion) and the second compensation lens 62 (which forms a 3.2° angle with the output light axis, deflecting the beam and changing its projection direction to compensate for positional shift). Finally, the light is projected onto the road surface from the light exit window at the second exit angle. The first exit angle is different from the second exit angle; the second exit angle is configured to compensate for the stretching distortion and positional shift of the predetermined pattern on the road surface caused by the bicycle's tilt.The first compensation lens 52, acting as a negative power lens, tilts its optical axis relative to the output optical axis, causing an asymmetric deflection of the passing light beam. This results in the beam cross-section contracting or expanding in the tilt direction, thus counteracting the stretching deformation of the projected pattern caused by changes in the road surface tilt angle. The second compensation lens 62, acting as a positive power lens, tilts its optical axis relative to the output optical axis, causing a deflection in the propagation direction of the entire projected beam. This keeps the projected pattern's position on the road surface stable, preventing lateral shift due to the bicycle's tilt.

[0030] When the bicycle returns from a tilted turning state to an upright state, the posture detection unit 4 detects that the tilt angle has decreased from 15° to 0°. The processor 72 re-queries the mapping table based on the updated tilt angle value to obtain the first compensation angle value of 0° and the second compensation angle value of 0°. It then controls the first stepper motor and the second stepper motor to rotate in opposite directions to their initial positions, so that the first optical adjustment element 5 returns to the first state, the second optical adjustment element 6 returns to the third state, and the projection optical module 3 resumes projecting the predetermined pattern at the first emission angle.

[0031] During the above operation, the processor 72 continuously reads the tilt angle signal from the attitude detection unit 4 at a sampling frequency of 200Hz, and updates the control signals for the first and second stepper motors at the same frequency, thereby achieving real-time tracking of tilt angle changes and real-time compensation of the projected pattern. The control program of the processor 72 adopts closed-loop control logic, that is, after each new tilt angle value is read, the mapping table is re-queried and the corresponding control signal is output, which does not depend on the control state at the previous moment, thus avoiding cumulative errors.

[0032] like Figure 4 As shown, a power interface and a power switch are provided on the rear cover of the lamp housing 1. The power interface is a waterproof DC power socket, which is electrically connected to the bicycle battery or an external power adapter via a wire. The power switch is a tactile push-button switch, which is connected in series in the positive power line and is used to control the power supply to and from the entire projector bicycle lamp. A power management circuit is provided between the power interface and the power switch. The power management circuit includes a step-down DC-DC converter chip, model LM2596, which is used to convert the input 6V to 36V DC voltage into stable 3.3V and 5V DC voltages, respectively powering the control unit 7, the attitude detection unit 4, the first stepper motor, and the second stepper motor.

[0033] The outer surface of the protective lens at the light-emitting window of the lamp housing 1 is also provided with an anti-reflective coating layer. This anti-reflective coating layer is a multilayer dielectric film composed of alternating layers of silicon dioxide and titanium dioxide, which is used to reduce the reflection loss of light on the surface of the protective lens and improve the emission efficiency of the projection beam.

[0034] This projectable bicycle light utilizes two independent adjustable optical elements, a first optical adjustment element 5 and a second optical adjustment element 6, to work collaboratively. Under the control of the control unit 7, it achieves specific state combinations such as "upright → first state + third state" and "tilted → second state + fourth state," resulting in the following beneficial effects: The first compensation lens 52 of the first optical adjustment element 5 acts as a negative power lens. In the second state, its optical axis forms a first compensation angle with the output optical axis of the light source module 2, producing an asymmetric deflection effect on the passing light beam to change the beam cross-sectional shape, thereby effectively compensating for the stretching distortion of the projected pattern caused by the bicycle's tilt. The second compensation lens 62 of the second optical adjustment element 6 acts as a positive power lens. In the fourth state, its optical axis forms a second compensation angle with the output optical axis of the projection optical module 3, deflecting the beam's propagation direction to change the projection direction, thereby effectively compensating for the positional shift of the projected pattern caused by the bicycle's tilt. The absolute value of the first compensation angle is greater than the absolute value of the second compensation angle. This design allows the two optical adjustment elements to each have their own functional focus and work collaboratively in the optical path, jointly achieving dual compensation for both the distortion and shift of the projected pattern. Compared to existing technologies that rely solely on rotating the projection lamp to adjust the light angle, this invention utilizes the coordinated compensation of dual optical elements. This not only maintains the positional stability of the projected pattern on the road surface but also preserves its shape fidelity, preventing stretching and deformation. The combined "position + shape" fidelity effect creates a synergistic effect. The control unit 7 uses a tilt angle-compensation angle mapping table stored in the memory 71 to achieve precise matching between the tilt angle and the compensation angles of the two optical adjustment elements. The processor 72 queries the mapping table based on the tilt angle signal detected in real-time by the attitude detection unit 4 and controls the first and second stepper motors to rotate the corresponding compensation angles, resulting in rapid compensation response and high control precision. The attitude detection unit 4 employs a MEMS accelerometer or gyroscope, offering advantages such as small size, low power consumption, and fast response, making it suitable for portable devices like bicycle lights with strict size and power consumption requirements. The pattern generation element 32 of the projection optical module 3 uses a fixed pattern sheet or a programmable spatial light modulator, capable of projecting various predetermined patterns such as bicycle icons, turn arrows, or safety warning boundary patterns to meet warning needs in different scenarios. The aluminum alloy material and heat dissipation fin design of the lamp housing 1 ensure efficient heat dissipation of the LED light source and extend the service life of the lamp; the silicone rubber sealing rings and waterproof sealant at each joint surface ensure the waterproof performance of the lamp in outdoor rain and fog weather.

[0035] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any person skilled in the art can easily conceive of various variations or substitutions within the technical scope disclosed in this application, and these should all be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A projectable bicycle light, characterized in that, include: The lamp housing (1) is mounted on the bicycle frame; A light source module (2) is disposed inside the lamp housing (1) and is used to emit illumination light and / or projection light; The projection optical module (3) is disposed inside the lamp housing (1) and located in the light output path of the light source module (2), and is used to form the light emitted by the light source module (2) into a projection beam with a predetermined pattern and project it onto the road surface. The attitude detection unit (4) is disposed inside the lamp housing (1) or on the bicycle body, and is used to detect the tilt angle of the bicycle and output the tilt angle signal. A first optical adjustment element (5) is disposed in the optical path between the light source module (2) and the projection optical module (3), and the first optical adjustment element (5) has a first state and a second state; The second optical adjustment element (6) is disposed on the light-emitting side of the projection optical module (3), and the second optical adjustment element (6) has a third state and a fourth state; The control unit (7) is electrically connected to the attitude detection unit (4), the first optical adjustment element (5), and the second optical adjustment element (6), respectively; When the bicycle is in an upright position, the posture detection unit (4) outputs a first tilt angle signal, the control unit (7) controls the first optical adjustment element (5) to remain in the first state and controls the second optical adjustment element (6) to remain in the third state according to the first tilt angle signal, and the projection optical module (3) projects the predetermined pattern at a first emission angle. When the bicycle is in a tilted turning state, the posture detection unit (4) outputs a second tilt angle signal, and the control unit (7) controls the first optical adjustment element (5) to switch to the second state and controls the second optical adjustment element (6) to switch to the fourth state according to the second tilt angle signal. The projection optical module (3) projects the predetermined pattern at the second emission angle. The first emission angle is different from the second emission angle, and the second emission angle is configured to compensate for the stretching distortion and / or positional shift of the predetermined pattern on the road surface caused by the bicycle tilt.

2. The projectable bicycle light according to claim 1, characterized in that, The first optical adjustment element (5) includes a first lens bracket (51) rotatably disposed in the lamp housing (1) and a first compensation lens (52) mounted on the first lens bracket (51); in the first state, the optical axis of the first compensation lens (52) coincides with the light output optical axis of the light source module (2); In the second state, a first compensation angle is formed between the optical axis of the first compensation lens (52) and the light output optical axis of the light source module (2).

3. The projectable bicycle light according to claim 2, characterized in that, The second optical adjustment element (6) includes a second lens bracket (61) rotatably disposed in the lamp housing (1) and a second compensation lens (62) mounted on the second lens bracket (61); in the third state, the optical axis of the second compensation lens (62) coincides with the light output optical axis of the projection optical module (3); In the fourth state, a second compensation angle is formed between the optical axis of the second compensation lens (62) and the output optical axis of the projection optical module (3).

4. The projectable bicycle light according to claim 3, characterized in that, The absolute value of the first compensation angle is greater than the absolute value of the second compensation angle.

5. The projectable bicycle light according to claim 3, characterized in that, The first compensation lens (52) is a negative power lens, and the second compensation lens (62) is a positive power lens.

6. The projectable bicycle light according to claim 1, characterized in that, The control unit (7) includes a memory (71) and a processor (72). The memory (71) stores a tilt angle-compensation angle mapping table. The processor (72) queries the mapping table according to the tilt angle signal output by the attitude detection unit (4) to determine the target state of the first optical adjustment element (5) and the second optical adjustment element (6).

7. The projectable bicycle light according to claim 6, characterized in that, The tilt angle-compensation angle mapping table stores multiple sets of preset tilt angle values ​​and a first compensation angle value and a second compensation angle value that correspond one-to-one with each preset tilt angle value; the processor (72) matches the corresponding first compensation angle value and the second compensation angle value from the mapping table according to the current tilt angle value corresponding to the tilt angle signal, and controls the first optical adjustment element (5) to rotate the first compensation angle value and controls the second optical adjustment element (6) to rotate the second compensation angle value respectively.

8. The projectable bicycle light according to claim 1, characterized in that, The attitude detection unit (4) is a MEMS accelerometer or gyroscope.

9. The projectable bicycle light according to claim 1, characterized in that, The predetermined pattern is at least one of a bicycle icon pattern, a turn arrow pattern, or a safety warning border pattern.

10. The projectable bicycle light according to claim 1, characterized in that, The projection optical module (3) includes a condenser lens (31), a pattern generating element (32) and a projection objective lens (33) arranged sequentially along the optical path. The pattern generating element (32) is a fixed pattern sheet or a programmable spatial light modulator.

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