A reflective programmable caustic display device and method based on a micromirror array

Abstract

This invention belongs to the field of optical element technology and discloses a reflective programmable caustic display device and method based on a micromirror array. The device includes an illumination module, a micromirror array module, a control and calculation module, and a drive module. This invention utilizes a micromirror array with continuous deflection capability, combined with a caustic inverse calculation process, to generate corresponding micromirror deflection angles based on the target image. This enables programmable control of the spatial position of the reflected light beams, allowing multiple beams to redistribute in the projection area and form a target caustic image. Compared to traditional HUD display solutions, this improves the freedom of light field control and light energy utilization efficiency, and facilitates high brightness, miniaturization, and dynamic display.

Description

Technical Field

[0001] This invention belongs to the field of optical element technology, and specifically discloses a reflective programmable caustic display device and method based on a micromirror array. Background Technology

[0002] Existing HUD display systems typically use liquid crystal displays, digital micromirror devices (DLPs), or other spatial light modulators to modulate the display light. DLPs primarily achieve grayscale adjustment by switching micromirrors between limited angles. Liquid crystal spatial light modulators rely on liquid crystal molecules to modulate the phase or polarization state of light. This makes it difficult for existing HUD systems to simultaneously achieve high brightness display, miniaturized optical path structure, and dynamic reconstruction of complex light fields. In particular, it is difficult to directly and continuously control the spatial propagation direction of the display beam, thus limiting the freedom of HUD display content and the efficiency of light energy utilization. Summary of the Invention

[0003] In view of this, the present invention provides a reflective programmable caustic display device based on a micromirror array to solve the above problems.

[0004] The specific implementation of this invention is as follows: A reflective programmable caustic display device based on a micromirror array, comprising: The lighting module is used to generate and output a beam of light. The micromirror array module is disposed in the optical path of the illumination beam and includes multiple micromirror units distributed in an array. Each micromirror unit has an independent degree of deflection and is used to continuously deflect the illumination beam at an angle within a preset range, so that the illumination beam propagates along a predetermined reflected optical path. The control calculation module is used to acquire the target image and run the caustic inverse calculation process, map the target image to the target light intensity distribution in the projection space, generate a target spot position set based on the target light intensity distribution, determine the target deflection angle corresponding to each micromirror unit according to the target spot position set, and generate the corresponding control signal. The driving module is electrically connected to the control calculation module and the micromirror array module, respectively. It is used to drive each micromirror unit to perform corresponding continuous angle deflection according to the control signal, so that the light beam reflected by each micromirror unit is redistributed and superimposed on the projection surface of the receiving component to form a caustic image with continuous spatial light intensity distribution corresponding to the target image.

[0005] As an alternative, the illumination module includes a light source and illumination optical elements; the illumination beam generated and output by the illumination module forms a preset angle with the normal direction of the micromirror array module and is incident on the micromirror array module, or is incident perpendicularly on the micromirror array module along the normal direction of the micromirror array module.

[0006] As an optional approach, the light source can be any one of a monochromatic laser, a multi-wavelength beam combiner, or a white light-emitting diode; the micromirror array module is a microelectromechanical system micromirror array chip; the driving module is an analog driving circuit, and the control signal is a continuously adjustable analog voltage signal.

[0007] As an alternative, the micromirror array module also includes a refractive optical field modulation component in its reflected optical path. The refractive optical field modulation component is an electrowetting microlens array, which is used to perform secondary refraction of the reflected beam and modulate the propagation direction of the illumination beam.

[0008] As an optional approach, a receiving component is also included, which is positioned on the propagation path of the reflected beam from the micromirror array module; the receiving component is any one of a static diffuse reflection screen, a vibration receiving component for realizing three-dimensional caustic display, or a stacked receiving component.

[0009] On the other hand, the present invention also provides a method for a reflective programmable caustic display based on a micromirror array, applied to the aforementioned reflective programmable caustic display device based on a micromirror array, comprising: Obtain the input target image; The control calculation module performs inverse caustics calculation on the target image, maps it to the target light intensity distribution in the projection space, and generates the corresponding set of target light spot positions; Based on the global energy constraint relationship between the target spot location set and the initial spot distribution, spot redistribution calculation is performed to obtain the mapping relationship between the initial spot and the target spot; The target reflection direction corresponding to each micromirror unit is calculated based on the mapping relationship and the reflection geometry. Calculate the target deflection angle of each micromirror unit based on the target reflection direction; The target deflection angle of each micromirror unit is converted into a drive control signal; The driving module applies continuous driving parameters to the micromirror array module according to the driving control signal, driving each micromirror unit to undergo corresponding continuous angular deflection, so that the illumination beam is reflected by the micromirror array module and reconstructs the caustic image corresponding to the target image on the projection surface of the receiving component.

[0010] As an optional method, spot redistribution calculation includes: The initial uniform spot grid corresponding to the micromirror unit in the initial undeflected state is extracted, and the energy of the initial uniform spot grid is redistributed based on the global optimal matching principle, so that the spot is redistributed to the target spot position set that matches the energy distribution of the target image while maintaining the total energy constraint.

[0011] As an optional method, the target reflection direction corresponding to each micromirror unit can be calculated based on the mapping relationship and the reflection geometry, including: The spatial propagation direction vector of the reflected light is calculated based on the spatial arrangement coordinates of each micromirror unit and the corresponding target spot position coordinates; the surface normal direction of the micromirror unit is determined by combining the incident light direction vector; and the deflection angle components of each micromirror unit on the orthogonal axis are determined by combining the spatial arrangement constraints of the micromirror array and the incident light path constraints.

[0012] As an optional method, converting the deflection angle of each micromirror unit into a drive control signal includes: A pre-calibrated micromirror unit driving response model is obtained. Based on the driving response model, the target deflection angle is segmented and mapped to generate the corresponding driving voltage matrix, which is then output as the driving control signal.

[0013] As an alternative approach, when the target image is a color image, a white light beam is used as the illumination beam. By utilizing the non-dispersion characteristics of the continuous angle deflection reflection of the micromirror unit, the wavelength components of the white light beam maintain consistent angle modulation characteristics on the spatial reflection path and are synchronously superimposed on the projection surface to form a color caustic image without color distortion.

[0014] The beneficial effects of this invention are as follows: This invention employs a micromirror array with continuous deflection capability, combined with a caustic inverse calculation process, to generate corresponding micromirror deflection angles based on the target image. This enables programmable control of the spatial position of the reflected beams, allowing multiple beams to redistribute within the projection area and form the target caustic image. Compared to traditional HUD display solutions, this improves the freedom of light field control and light energy utilization efficiency, and facilitates high brightness, miniaturization, and dynamic display. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall structure of the reflective programmable caustic display device of the present invention; Figure 2 This is a schematic diagram of the caustic inverse calculation and micromirror control process of the present invention. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the various embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been presented in the various embodiments of the present invention to enable the reader to better understand the present invention. However, the technical solutions claimed in the present invention can be implemented even without these technical details and various changes and modifications based on the following embodiments.

[0017] With the development of smart cockpit technology, head-up display (HUD) systems are increasingly being applied to vehicle information display scenarios. HUD systems need to project navigation information, driver assistance information, and multimedia information into the driver's field of vision, overlaying virtual display content with the real road environment. Due to the limited interior space of vehicles and the strong ambient light interference in the driving environment, HUD display systems typically require high light energy utilization efficiency, a large degree of display freedom, and a small optical structure size. Existing HUD display solutions typically use liquid crystal display modules, digital micromirror devices, or other spatial light modulators to modulate the light beam. Digital micromirror device-based solutions usually change the beam propagation path by switching the micromirrors between limited angular states and use time modulation to form different grayscale levels; liquid crystal spatial light modulator-based solutions mainly achieve image modulation by changing the phase, polarization, or amplitude characteristics of the beam. While these solutions can meet conventional image display requirements, they still have certain limitations when continuous adjustment of the beam propagation direction and dynamic adjustment of spatial light energy distribution according to the target image are needed.

[0018] Specifically, in existing micromirror display solutions, micromirror units are typically used to achieve on / off optical path switching. A single micromirror lacks sufficient continuous control over the direction of reflected light, making it difficult to directly utilize a large number of tiny beam units to form complex spatial light field distributions. Furthermore, traditional display methods primarily rely on pixel position and brightness information for image reconstruction, without considering the reverse design of the propagation path of the reflected beam in the projection space. This limits the optical system's ability to achieve high-degree-of-freedom caustic displays, special light field displays, and dynamic 3D displays. Therefore, a display device is needed that can utilize the continuous deflection capability of each micromirror unit in a micromirror array to calculate the spatial distribution of the beam in reverse from the target image and control each micromirror unit to change its reflection direction, thereby improving the flexibility of light field control in HUD systems.

[0019] Please see Figure 1 This embodiment provides a reflective programmable caustic display device based on a micromirror array. By setting a micromirror array module with continuous deflection capability, each micromirror unit is used as an independent reflection control unit. Combined with the caustic inverse calculation process, the beam propagation direction corresponding to each micromirror unit is determined according to the target image, so that multiple reflected beams are redistributed in the projection area to form the target caustic image.

[0020] In this embodiment, the display device includes an illumination module, a micromirror array module, a control and computing module, and a driving module. The illumination module provides an illumination beam to the micromirror array module. The micromirror array module is positioned in the propagation path of the illumination beam and includes multiple micromirror units arranged in an array. Each micromirror unit can continuously deflect at a preset angle to change the propagation direction of the corresponding reflected beam.

[0021] The control and calculation module acquires the target image to be displayed and performs a caustic inverse calculation process based on the target image. This calculation process first converts the target image into a target light intensity distribution in the projection space, then determines the set of target spot positions to be formed based on the target light intensity distribution, and further calculates the target deflection angle corresponding to each micromirror unit. The driving module applies corresponding driving signals to each micromirror unit according to the control signals output by the control and calculation module, causing micromirror units at different positions to deflect at different angles.

[0022] In this embodiment, the light beams reflected by each micromirror unit are redistributed in space according to the target image requirements. The reflected light beams from multiple micromirror units are superimposed on the projection surface to form a continuous spatial light intensity distribution, enabling the projection area to present a caustic display effect corresponding to the target image. Furthermore, the micromirror array module can employ a microelectromechanical system (MEMS) micromirror array chip. Compared to micromirror structures with only a fixed flip state, the micromirror units in this embodiment can continuously adjust the reflection direction according to control signals, allowing the same illumination beam to generate different spatial propagation paths depending on the target display content.

[0023] Please refer to it again. Figure 1 This embodiment provides a reflective programmable caustic display device based on a micromirror array. It includes an illumination module, a micromirror array module, a control and calculation module, a driving module, and a projection surface. The illumination module generates and outputs an illumination beam with preset optical characteristics. The micromirror array module is positioned in the propagation path of the illumination beam to spatially modulate the incident beam. The control and calculation module performs inverse caustic calculations based on the target image, generating control parameters corresponding to each micromirror unit. The driving module drives each micromirror unit in the micromirror array module to continuously deflect according to the control signals output by the control and calculation module, causing the reflected beam to form a target caustic image on the projection surface of the receiving component. The receiving component is positioned in the reflected optical path of the micromirror array module to carry the generated caustic image; its receiving surface facing the reflected beam is the projection surface.

[0024] The display device of this embodiment can be applied to a vehicle head-up display (HUD) system. In specific applications, the display device can be placed inside the vehicle's dashboard or near the windshield. By spatially adjusting the reflected light beam, the generated virtual image is projected into the driver's field of vision. Because this embodiment uses a display method based on beam direction modulation, it does not require a traditional display panel to directly form a complete image, thus making it suitable for application environments with limited space and requiring high-brightness displays.

[0025] The aforementioned lighting module includes a light source and lighting optical elements. The light source is used to output an initial illumination beam for display. In one embodiment, the light source can be a monochromatic laser to provide a highly directional illumination beam; in another embodiment, the light source can be a multi-wavelength beam combiner to achieve multi-color display through the combination of multiple light sources of different wavelengths; in yet another embodiment, the light source can be a white light-emitting diode (LED) for forming a color caustic display image.

[0026] The illumination optical element is set in the output optical path of the light source to collimate, expand, homogenize or shape the illumination beam so that the illumination beam entering the micromirror array module meets the preset illumination conditions.

[0027] In one implementation, such as Figure 1 As shown, the illumination beam generated and output by the illumination module forms a preset angle with the normal direction of the micromirror array module and is incident on the micromirror array module (this can also be referred to as oblique incidence or non-perpendicular incidence). By making the illumination beam form a preset angle with the normal direction of the micromirror array module, the micromirror unit can have a larger space for adjusting the reflection direction and facilitate the spatial separation of the incident light path and the reflected light path.

[0028] In another embodiment, the illumination beam output by the illumination module can also be incident perpendicularly along the normal direction of the plane containing the micromirror array module. Using a perpendicular incidence method simplifies the optical structure and helps reduce the overall size of the display device. It should be noted that this embodiment does not limit the specific incident method of the illumination beam, as long as it allows the illumination beam to enter the micromirror array module and be reflected by the micromirror units to form a reflected beam with an adjustable propagation direction.

[0029] The micromirror array module comprises multiple micromirror units arranged in an array, each micromirror unit being used to independently control the reflection of an incident light beam within its corresponding region. In one embodiment, the micromirror array module employs a microelectromechanical system (MEMS) micromirror array chip. The micromirror array chip includes multiple micromirror units arranged in a two-dimensional array, each micromirror unit having an independent driving structure, enabling micromirror units at different positions to generate different deflection states according to corresponding control signals. Unlike the micromirror structure in traditional digital micromirror devices, which only has a limited number of flip states, the micromirror units in this embodiment can continuously deflect within a preset angle range. By continuously adjusting the spatial orientation of the micromirror units, the reflection direction of the incident light can be continuously changed, allowing each micromirror unit to function as an independent beam direction adjustment unit.

[0030] Specifically, when the illumination beam is incident on the micromirror array module, different micromirror units adjust their deflection angles according to corresponding control parameters, causing micromirror units at different positions to generate reflected beams in different directions. The reflected beams output by multiple micromirror units together form a spatially adjustable beam array, which further forms the target light intensity distribution on the projection surface.

[0031] In this embodiment, the micromirror array module is used to change the spatial propagation direction of each beam unit, forming a caustic display effect through the spatial superposition of a large number of beam units. The control calculation module is used to realize the conversion between the target image and the micromirror control parameters. It may include an image input unit, a caustic inverse calculation unit, and a control signal generation unit. Among them, the image input unit is used to acquire the target image to be displayed, such as vehicle navigation information, driving assistance prompts, or other graphic information that needs to be displayed.

[0032] The caustic inverse calculation unit is used to establish the corresponding target light intensity distribution based on the target image, and further calculates the set of target spot positions used to form this target light intensity distribution. By inversely solving the target spot positions, the target reflection direction and target deflection angle corresponding to each micromirror unit are determined.

[0033] The control signal generation unit generates control signals based on the target deflection angle corresponding to each micromirror unit and outputs them to the drive module. In one embodiment, the control calculation module can be implemented using a processor, graphics processor, dedicated computing chip, or other electronic devices with computing capabilities. The control calculation module can dynamically update the control parameters of each micromirror unit based on the real-time input image, thereby achieving dynamic caustic display.

[0034] The drive module is connected to both the control calculation module and the micromirror array module, and is used to drive the micromirror units to generate corresponding deflections based on the control signals output by the control calculation module. In one embodiment, the drive module uses an analog drive circuit to control the deflection state of the micromirror units by outputting a continuously adjustable analog voltage signal. Since the actual deflection response of the micromirror units may be affected by structural parameters, drive characteristics, and manufacturing errors, the drive module can combine a pre-calibrated drive response relationship to convert the target deflection angle output by the control calculation module, so that the output drive signal matches the actual micromirror deflection state.

[0035] Through the above structure, the digital calculation results output by the control calculation module can be converted into the actual continuous motion state of the micromirror array module, thereby realizing the reconstruction of the light field corresponding to the target image.

[0036] In one implementation scenario, a projection surface is positioned within the reflective optical path of the micromirror array module to receive the reflected light beam modulated by the module. When multiple micromirror units deflect at different angles according to control signals, the light beams reflected from different micromirror units propagate along different spatial directions, forming a superposition of light intensity at corresponding positions on the projection surface. Since the position and energy distribution of each beam are pre-calculated by the control calculation module, the final spatial light intensity distribution corresponds to the target image.

[0037] In this embodiment, the caustic image is formed by the redistribution and superposition of reflected light beams from multiple micromirror units during spatial propagation, thereby realizing programmable caustic display based on beam direction control.

[0038] Please see Figure 2 In this embodiment, after the control calculation module acquires the target image, it performs caustic inverse calculation on the target image to determine the beam control parameters corresponding to each micromirror unit. The caustic inverse calculation process is not a traditional method of directly controlling the corresponding micromirror unit based on the pixel position of the target image. Instead, it involves inversely solving for the spatial propagation path of the illumination beam after reflection by the micromirror array module, based on the light intensity distribution required to be formed by the target image in the projection space, thereby obtaining the target spot position corresponding to each micromirror unit.

[0039] Specifically, the control calculation module first acquires the input target image and establishes the corresponding target light intensity distribution based on the image information in the target image. In one embodiment, the control calculation module performs grayscale processing, brightness normalization processing, or color information analysis processing on the target image, converting the target image into light intensity requirements corresponding to different spatial positions on the projection surface, so that the image features in the target image are converted into a spatial energy distribution that can be used for beam control.

[0040] After establishing the target light intensity distribution, the control calculation module further acquires the initial light spot distribution corresponding to the micromirror array module in its initial state. Specifically, when each micromirror unit is in a preset initial deflection state, the illumination beam, after being reflected by each micromirror unit, forms an initial light spot grid composed of multiple light spots on the projection surface. The initial light spot grid corresponds to the spatial arrangement position of each micromirror unit in the micromirror array module, and each initial light spot corresponds to the reflected beam generated by one micromirror unit.

[0041] Since the initial light spot distribution is usually in a regular arrangement, while the light intensity distribution corresponding to the target image has different spatial distribution characteristics, it is necessary to redistribute the initial light spot so that the light beams reflected by multiple micromirror units can form a light intensity distribution on the projection surface that meets the requirements of the target image.

[0042] In this embodiment, the control calculation module performs spatial redistribution processing on the initial light spots based on the energy constraint relationship between the initial light spot distribution and the target light intensity distribution. Specifically, the initial light spots are taken as beam units to be adjusted, and the light intensity requirement of the corresponding region of the target image is taken as the target constraint. The target movement position corresponding to each initial light spot is determined through global optimization, thereby establishing a mapping relationship between the initial light spots and the target light spots. In one implementation, the light spot redistribution process is calculated using an optimal transmission algorithm. Through the optimal transmission algorithm, the light energy transmission path corresponding to each light spot can be optimized according to the difference between the initial light spot distribution and the target light intensity distribution, so that multiple initial light spots are redistributed to the target position while satisfying the overall light energy constraint.

[0043] Specifically, the control calculation module divides the projection surface into multiple target regions based on the target light intensity distribution corresponding to the target image, and determines the amount of light energy required for each target region; then, based on the spatial position of each spot in the initial spot grid and the light energy requirement of the target region, it calculates the set of target spot positions corresponding to each initial spot.

[0044] Using the above calculation method, a single micromirror unit does not directly correspond to a fixed pixel position in the target image, but rather participates in the reconstruction of the target image according to the overall light field distribution requirements. For example, multiple micromirror units located at different positions in the initial light spot distribution can guide the reflected light beam to different regions in the target image, and the caustic effect corresponding to the target image is formed by the spatial superposition of multiple reflected light beams on the projection surface.

[0045] Furthermore, after obtaining the target spot position set, the control calculation module determines the target position to which each micromirror unit needs to reflect the incident beam according to the correspondence between the target spot position set and each micromirror unit in the micromirror array module, and uses the target position as the input parameter for subsequent micromirror deflection angle calculation.

[0046] In this embodiment, the caustic inverse calculation process establishes a mapping relationship from the target image to the set of target light spot positions, enabling the display system to adjust the deflection state of each micromirror unit in the micromirror array module in real time according to different input images. Compared with the method of directly controlling the light intensity through display pixels, this embodiment realizes programmable caustic display based on light field reconstruction by planning the spatial position of the reflected beam as a whole.

[0047] It should be noted that the caustic inverse calculation process in this embodiment is not limited to the above-mentioned optimal transmission algorithm. Other global optimization algorithms that satisfy the target light intensity distribution constraints can also be used, as long as the corresponding target spot position set can be generated based on the target image and the beam control parameters of the micromirror unit can be further determined.

[0048] In this embodiment, after obtaining the target spot position set, the control calculation module further calculates the direction of the reflected beam to be generated by each micromirror unit according to the spatial position of each micromirror unit and the corresponding target spot position, and further determines the target deflection angle corresponding to each micromirror unit, so as to achieve precise control of the propagation path of the reflected beam.

[0049] Specifically, the control calculation module first obtains the spatial arrangement coordinates of each micromirror unit in the micromirror array module and the spatial coordinates of the corresponding target spot position on the projection surface. Since each micromirror unit corresponds to an independent reflected beam, the target propagation direction of the reflected beam corresponding to that micromirror unit can be determined based on the spatial geometric relationship between the position of the micromirror unit and the position of the target spot.

[0050] In one implementation, the control calculation module calculates the spatial propagation direction vector from the micromirror unit to the target light spot position based on the position coordinates of the micromirror unit and the target light spot position coordinates. This spatial propagation direction vector represents the target propagation direction of the light beam reflected by the corresponding micromirror unit in space.

[0051] Furthermore, the control calculation module obtains the incident beam direction vector output by the illumination module, and combines the incident beam direction vector with the target propagation direction vector to determine the target normal direction that the micromirror unit's reflecting surface needs to satisfy according to the light reflection law.

[0052] Specifically, since the incident ray, reflected ray, and normal to the reflecting surface satisfy a reflection geometry relationship—that is, a geometric constraint relationship between the propagation direction of the reflected light and the normal direction of the micromirror surface determined based on the position coordinates of the micromirror unit, the position of the target light spot, and the propagation direction of the incident light—the normal direction of the micromirror surface that satisfies the reflection path can be solved in reverse once the incident light direction and the target reflected light direction are determined. The control calculation module then determines the spatial attitude that the micromirror unit needs to adjust based on the target normal direction.

[0053] In this process, geometric constraints encompass both the spatial arrangement constraints of the micromirror array and the incident light path constraints. Specifically, the spatial arrangement constraints of the micromirror array refer to the spatial geometric configuration restrictions jointly determined by the physical spatial coordinates of each micromirror unit in the array and the spatial coordinates of the corresponding target spot position in the projection plane. This constraint is used to determine the spatial propagation direction vector of the reflected beam. The incident light path constraints refer to the beam incident direction restrictions determined by the physical architecture and optical path design of the illumination module, which are represented as the incident beam direction vector as a known constant input during the calculation process. By combining the spatial arrangement constraints and the incident light path constraints, the control calculation module can uniquely and inversely calculate the target normal direction based on the optical reflection law, and further determine the deflection angle components of each micromirror unit on the orthogonal axis based on the target normal direction.

[0054] As an alternative approach, let the surface normal vector of the micromirror unit (i,j) in the micromirror array module be nᵢⱼ, and the incident light direction vector output by the illumination module be... k in According to the law of optical reflection, the direction vector of the reflected light generated by this micromirror unit is... k out The calculation formula is: ; The spatial deflection of the micromirror unit is achieved by changing its normal vector. If the micromirror unit is deflected about the X-axis by an angle of αᵢⱼ and about the Y-axis by an angle of βᵢⱼ, then the geometric correspondence between its surface normal vector nᵢⱼ and the rotation matrix is: ; In the formula, and Let these represent the rotation matrices about the X-axis and the Y-axis, respectively. This is the surface normal vector of the micromirror unit when it is in its initial undeflected state.

[0055] Furthermore, let the projection plane be plane z=D, and the reflected light along the direction vector k out The light propagates and intersects with the projection surface; the intersection point is the location of the reflected light spot, and its corresponding spatial coordinates (x') are... ij, y' ij The formula for calculating ) is: ; In the formula, k out x、k out, y and k out z represents the direction vector of the reflected light, and k represents the direction vector of the reflected light. out The components lie on three orthogonal coordinate axes in space. Therefore, the brightness of the light spot is determined by the incident light intensity and the micromirror reflectivity (independent of the deflection angle), while the specific spatial position of the light spot on the projection surface (x')... ij ,y' ij The position of each light spot on the projection surface can be controlled by adjusting the deflection angle of each micromirror unit, thereby reconstructing a continuous spatial light intensity distribution.

[0056] In this embodiment, the micromirror units in the micromirror array module can have dual-axis deflection degrees of freedom. For example, the micromirror units can adjust their angles around two mutually perpendicular rotation axes. The control calculation module decomposes the target normal direction into angular components along the two rotation axes based on the attitude difference between the target normal direction and the initial normal direction of the micromirror unit, and obtains the target deflection angle of the micromirror unit in each rotation axis direction.

[0057] In this way, the micromirror units at different positions can be independently adjusted according to the position of the corresponding target light spot, so that the light beams reflected by different micromirror units propagate along a predetermined path and finally form a spatial light intensity distribution on the projection surface that corresponds to the target image.

[0058] Furthermore, since the driving response of the micromirror units in the actual micromirror array module usually has certain nonlinear characteristics, after determining the target deflection angle, the control calculation module or driving module also needs to convert the driving parameters of the target deflection angle.

[0059] Specifically, the system pre-acquires a micromirror unit drive response model. This model describes the correspondence between the input drive parameters of the micromirror unit and the actual deflection angle. In one implementation, the actual deflection angle of the micromirror unit under different drive voltage conditions can be obtained through experimental calibration, and a mapping relationship between the drive voltage and the deflection angle can be established. After the control calculation module obtains the target deflection angle corresponding to each micromirror unit, it matches and converts the target deflection angle according to the drive response model to generate the corresponding drive control signal.

[0060] In one implementation, the drive response model can employ a pre-calibrated nonlinear mapping lookup relationship. The control calculation module inputs the target deflection angle into the mapping relationship to obtain the corresponding drive voltage value, and generates a drive voltage matrix based on the drive voltage values ​​corresponding to all micromirror units. Specifically, due to the nonlinear deflection characteristics of MEMS micromirrors (i.e., the voltage-angle relationship is nonlinear), this nonlinear compensation conversion is achieved through a pre-calibrated drive voltage-deflection angle lookup table function relationship, the mathematical expression of which is: V=H(α,β), where α and β are the target deflection angles of the micromirror unit on the orthogonal control axis, respectively; H represents the pre-calibrated nonlinear mapping function; and V is the drive voltage matrix actually output to the drive circuit after conversion. Through this mapping lookup table for nonlinear compensation conversion, the control calculation module can accurately and quickly convert the mathematically solved deflection angle matrix into the drive voltage matrix required by the hardware, thereby overcoming the nonlinear response of the micromirror and achieving high-precision angle attitude control.

[0061] After receiving the drive control signal, the drive module outputs corresponding continuous drive parameters to each micromirror unit in the micromirror array module, so that each micromirror unit produces a continuous angular deflection corresponding to the target deflection angle.

[0062] In this embodiment, the driving parameter can be a continuously adjustable analog voltage signal, or other driving parameters that can control the deflection state of the micromirror can be used depending on the specific structure of the micromirror unit. By calibrating and compensating the driving response relationship, the impact of micromirror manufacturing errors and driving nonlinearity on the display effect can be reduced, and the matching accuracy between the target spot position and the actual formed spot position can be improved.

[0063] After the above process, the control calculation module completes the reverse calculation from the target image and the target spot position set to the micromirror target deflection angle. The drive module further converts the calculation results into the actual mechanical movement of the micromirror array module, so that the light beam reflected by each micromirror unit propagates along the preset spatial path and forms the corresponding caustic display image on the projection surface.

[0064] When applied to a HUD display system, the calculation process can be updated in real time according to the vehicle's display content. For example, when the navigation path, road prompts, or driver assistance signs change, the control calculation module can re-execute the caustic inverse calculation and update the deflection state of each micromirror unit, thereby achieving a dynamically programmable display.

[0065] In one specific embodiment, the micromirror array module employs a 32×32 MEMS micromirror array chip to achieve caustic display. Optionally, the MEMS micromirror array chip includes multiple micromirror units arranged in a two-dimensional matrix, comprising a total of 32×32 micromirror units, or 1024 independently controllable micromirror units. Each micromirror unit corresponds to an independent beam control unit for adjusting the direction of the illumination beam incident on the surface of that micromirror unit.

[0066] To further ensure display accuracy and light energy utilization efficiency, in a specific application scenario, the physical parameters of the 32×32 MEMS micromirror array chip are configured as follows: the aperture of each micromirror unit is set to 300μm, and the pitch between adjacent micromirror units is 320μm. Each micromirror unit can achieve a continuous deflection range of ±5° in both the X and Y axes, and independent addressing control of each micromirror unit is achieved through analog voltage drive, with a mechanical response time of less than 1ms, meeting the high-speed dynamic refresh requirements of the display screen.

[0067] In the corresponding optical path configuration, the illumination module uses a 450nm blue laser with a power of 50mW as the light source, the projection surface uses a white diffuse reflection screen, and the projection distance D from the micromirror array module to the projection surface is set to 200mm. Thanks to the low absorption loss characteristics of the pure reflection optical path and the high reflectivity coating on the micromirror surface, the system light energy utilization rate in this embodiment is greater than 85%, and the contrast ratio of the 32×32 resolution target caustic image generated on the projection surface can reach approximately 50:1, significantly improving the actual luminous efficiency and image quality of the display system.

[0068] In the initial operating state, each micromirror unit maintains a preset initial posture. After the illumination beam is reflected by each micromirror unit, it forms an initial light spot grid on the projection surface corresponding to the spatial arrangement of the micromirror array. Each initial light spot corresponds to a reflected beam generated by one micromirror unit. After acquiring the target image to be displayed, the control calculation module establishes the corresponding target light intensity distribution based on the target image and performs a global redistribution calculation on the 1024 initial light spots based on the global energy constraint relationship between the initial light spot grid and the target light intensity distribution.

[0069] In this embodiment, the global energy constraint relationship is used to describe the overall energy matching relationship between the initial light spot distribution and the target light intensity distribution. Specifically, during the light spot redistribution process, the control calculation module ensures that the total light energy corresponding to the redistributed target light spot set is basically consistent with the initial light spot distribution, and matches the position distribution and light intensity distribution of each target light spot with the target light intensity distribution corresponding to the target image. By establishing the global energy constraint relationship, the light spot redistribution process does not depend on the independent adjustment of individual light spots, thereby improving the matching degree between the target light spot position set and the target image light intensity distribution.

[0070] Therefore, the control calculation module takes the 32×32 initial light spot grid as input and the light intensity distribution corresponding to the target image as a constraint. It calculates the target position that each initial light spot needs to move to using the optimal transmission algorithm, obtaining a set of target light spot positions corresponding one-to-one with each of the 1024 micromirror units. The optimal transmission algorithm used here follows the global optimal matching principle to establish the correspondence between the initial light spots and the target light spots. The global optimal matching principle means that, based on a comprehensive consideration of the positional relationship, energy distribution relationship, and light intensity requirements of the target image between all initial light spots and target light spots, the correspondence between multiple light spots is optimized as a whole to obtain the light spot mapping result with the best overall matching effect, eliminating the need for independent adjustments to individual light spots.

[0071] For example, for a bright area in the target image, the control calculation module can redistribute the reflected beams corresponding to multiple micromirror units to the area according to the light energy requirements of the target area, so that multiple light spots are superimposed at the target position to form a higher light intensity; for a low-brightness area in the target image, the light spot density of the corresponding area is reduced or the light energy distribution is adjusted to form a lower light intensity, thereby realizing the continuous grayscale caustic display corresponding to the target image.

[0072] Furthermore, after obtaining the 32×32 target spot position set, the control calculation module calculates the target reflection direction corresponding to each of the 1024 micromirror units based on the spatial coordinates of each micromirror unit and the corresponding target spot position coordinates, and further obtains a 32×32 target deflection angle matrix. Each element in the target deflection angle matrix corresponds to the target deflection angle of a micromirror unit, which is used to represent the spatial attitude change that the micromirror unit needs to produce.

[0073] Subsequently, the control calculation module converts the target deflection angle matrix into a corresponding drive control matrix based on the pre-calibrated micromirror drive response relationship. The drive control matrix contains drive parameters corresponding to 1024 micromirror units, used to control the drive module to output corresponding continuous drive signals to each micromirror unit.

[0074] After receiving the drive control matrix, the drive module independently drives each micromirror unit in the 32×32 MEMS micromirror array, causing micromirror units at different positions to produce continuous angular deflections of varying degrees. Since the reflection direction corresponding to each micromirror unit is determined through inverse caustic calculation, the light beam reflected by the 1024 micromirror units can be rearranged on the projection surface according to the spatial light intensity distribution corresponding to the target image, and the target caustic image is formed by beam superposition.

[0075] In this embodiment, a 32×32 MEMS micromirror array is used as a specific implementation to illustrate the coordination relationship between the micromirror array module, the caustic inverse calculation process, and the drive control process in this invention. This invention does not limit the specific array size of the micromirror array module; in practical applications, other numbers of micromirror units can be used depending on the display resolution, optical system size, and display effect requirements.

[0076] Through the above implementation methods, the present invention utilizes multiple independently deflected micromirror units in a MEMS micromirror array to transform the pixel control method in the traditional display system into a beam propagation direction control method, thereby realizing a programmable caustic display based on light field reconstruction.

[0077] Based on the above embodiments, the micromirror array-based reflective programmable caustic display device in this embodiment can also adjust the illumination method, optical path structure and light field control structure according to the actual application scenario to meet the optical requirements of different display environments.

[0078] In one embodiment, the illumination module may include a light source and an illumination optical element disposed in the output optical path of the light source. The light source is used to provide an illumination beam entering the micromirror array module, and the illumination optical element is used to shape the illumination beam so that the illumination beam is incident on the micromirror array module in a preset optical state.

[0079] Specifically, the light source can be any one of a monochromatic laser, a multi-wavelength beam combining light source, or a white light emitting diode, depending on the display requirements.

[0080] When a monochromatic laser is used as the light source, the laser beam's good directionality and high light energy concentration capability can improve the light energy utilization efficiency of the micromirror array module when controlling the beam direction. This is suitable for applications requiring high brightness or high contrast displays. For example, in vehicle HUD systems, a specific wavelength laser light source can be used to ensure good visibility of the displayed content even under strong ambient light conditions.

[0081] When using a multi-wavelength combined light source, multiple light sources of different wavelengths can be combined to form a composite illumination beam, enabling the micromirror array module to generate caustic images with different color information according to the target image requirements. Beams of different wavelengths can be directionally modulated by the micromirror array module and spatially superimposed on the projection surface.

[0082] When a white light-emitting diode (LED) is used as the light source, multiple wavelength components contained in white light can be used to form a color display effect. Since this embodiment uses a micromirror unit to control the direction of beam propagation, rather than using optical elements with dispersive properties for beam splitting, it can reduce the color shift problem caused by differences in the propagation paths of different wavelength beams.

[0083] Furthermore, the incident light path between the illumination module and the micromirror array module can be adjusted according to the display system structure. In one embodiment, the illumination beam generated and output by the illumination module forms a preset angle with the normal direction of the micromirror array module and is incident on the micromirror array module. Specifically, the propagation axis direction of the illumination beam forms a non-zero preset angle of less than 90 degrees with the surface normal direction of the micromirror array module, and the incident beam propagates along the target direction after being reflected by the micromirror units.

[0084] When the illumination beam is incident at a preset angle to the normal direction of the micromirror array module, the incident light path and the reflected light path can be spatially separated, thus facilitating the setting of the positional relationship between the light source, the micromirror array module, and the projection surface. Simultaneously, because the micromirror units have continuous deflection capabilities, this incident method formed by a preset angle can provide a large range of reflection direction adjustment, enabling the system to cover a larger display area.

[0085] For example, in vehicle HUD applications, the illumination module can be positioned to the side of the display device, so that the illumination beam forms a preset angle with the normal direction of the micromirror array module and illuminates the micromirror array module. The reflected beam, modulated by the micromirror array module, propagates towards the vehicle's windshield and forms a virtual display image within the driver's field of vision. In another embodiment, the illumination beam can also enter the micromirror array module with a perpendicular incidence, that is, the illumination beam propagates along the normal direction of the plane where the micromirror array module is located and illuminates the micromirror units. Using a perpendicular incidence method simplifies the overall optical path structure, allowing for a more compact spatial layout between the illumination module, the micromirror array module, and the projection area, which helps to reduce the size of the display device. For example, in vehicle display modules or portable display devices with high space constraints, a perpendicular incidence structure can be used to reduce the number of optical components. It should be noted that this embodiment does not limit the specific incident angle or incident method of the illumination beam. As long as the illumination beam can form a preset angle with the normal direction of the micromirror array module, or be incident perpendicularly along the normal direction of the micromirror array module, so as to enter the micromirror array module and be reflected by the micromirror unit to form a reflected beam with an adjustable propagation direction, it is acceptable.

[0086] Furthermore, a refractive optical field modulation component can be incorporated into the reflected optical path of the aforementioned micromirror array module to further improve the accuracy of the reflected beam direction adjustment. In one embodiment, the refractive optical field modulation component is positioned between the micromirror array module and the projection surface, and is implemented using an electrowetting microlens array. The electrowetting microlens array includes multiple microlens units with adjustable focal lengths or refractive states. Each microlens unit can change the droplet interface morphology according to an applied electrical signal, thereby adjusting the refractive characteristics of the corresponding region. When the reflected beam output from the micromirror array module passes through the electrowetting microlens array, the array can further adjust the refraction of the reflected beam, precisely correcting the beam propagation direction.

[0087] In this embodiment, the refraction adjustment process constitutes a secondary optical control process for the reflected beam. Specifically, the illumination beam reflected by the micromirror array module first undergoes initial adjustment of its propagation direction through angular deflection by the micromirror units. It then enters the electrowetting microlens array, where the refraction generated by the array further alters the beam's propagation direction, thus achieving a secondary adjustment of the reflected beam's propagation path. Through this two-stage beam control method, the micromirror array module enables a wider range of beam direction adjustments, while the electrowetting microlens array provides fine compensation for the beam direction, improving the accuracy of caustic spot position adjustment.

[0088] In this embodiment, the micromirror array module is mainly used to achieve a wide range of beam direction adjustment, while the electrowetting microlens array is used to achieve more precise optical field adjustment. By combining the two, a composite beam control method of coarse and fine adjustment can be formed, improving the matching accuracy between the target spot position and the actual formed spot position.

[0089] For example, when the micromirror unit is limited by the mechanical structure and has a minimum deflection step or manufacturing error, the reflected beam can be compensated and adjusted by the electrowetting microlens array, so that the light intensity distribution finally projected onto the projection surface is closer to the target image requirements.

[0090] Furthermore, in another embodiment, the projection surface can take different forms depending on the display requirements. In one embodiment, a static diffuse reflection screen is used as the projection surface. After the reflected light beam, modulated by the micromirror array module, shines on the diffuse reflection screen, a two-dimensional caustic display image is formed through spatial light intensity superposition. This method has a simple structure and is suitable for conventional image display or HUD system testing environments. In another embodiment, a high-frequency vibrating projection surface is used to achieve three-dimensional caustic display.

[0091] Specifically, the high-frequency vibrating projection surface can move periodically in space, so that the caustic images formed at different times correspond to different spatial positions. By controlling the propagation direction of the beam output by the micromirror array module and combining it with the spatial movement of the projection surface, a display effect with spatial depth variation can be formed in the observation area.

[0092] In another embodiment, the projection surface can employ a multi-depth stacked projection structure. This structure includes multiple display layers arranged along the light propagation direction, each corresponding to a different spatial depth. The control and calculation module determines the beam distribution corresponding to different depth layers based on the target display content, enabling the reflected beams output by the micromirror array module to form caustic images at different depth positions.

[0093] Through the above methods, the display device in this embodiment can not only achieve two-dimensional caustic display, but also achieve a display effect with spatial depth information by combining different forms of projection structures.

[0094] In summary, this embodiment expands the types of illumination sources, incident methods, and light field control structures, enabling the micromirror array-based reflective programmable caustic display device to adapt to different application scenarios. Specifically, the micromirror array module provides the ability to adjust the main beam direction, and additional optical structures further improve the precision of light field control, thereby enhancing the adaptability and scalability of the display system.

[0095] Based on the above embodiments, this embodiment also provides a color caustic display method, which uses a white light illumination beam and a micromirror array module to synchronously modulate the beams of different wavelengths, enabling the display device to form a caustic image with color information.

[0096] Specifically, when the target image is a color image, the control calculation module first acquires the color information in the target image and establishes a color target light intensity distribution based on the light intensity requirements corresponding to different color regions. Subsequently, the control calculation module performs a caustic inverse calculation process based on the color target light intensity distribution to determine the target deflection angle corresponding to each micromirror unit.

[0097] In this embodiment, the illumination module uses a white light-emitting diode as the illumination source. The white light beam includes spectral components across multiple wavelength ranges, such as the red, green, and blue light bands. After being processed by the illumination optics, the white light beam enters the micromirror array module with a preset incident pattern.

[0098] Since the micromirror units in the micromirror array module primarily adjust the propagation direction of the incident light beam by changing the spatial orientation of the reflecting surface, the modulation process is based on changes in the beam reflection direction, rather than utilizing optical materials to generate different refraction angles for different wavelengths. Therefore, at the same micromirror unit, white light beams with different wavelength components can maintain a basically consistent reflection direction.

[0099] Specifically, when a micromirror unit deflects according to the target deflection angle output by the control calculation module, different wavelength beams incident on that micromirror unit propagate according to the same reflection geometry, enabling red, green, blue, and other color beams to reach the projection surface along the same spatial path. Subsequently, each wavelength beam is synchronously superimposed at the corresponding position on the projection surface according to the color requirements in the target image, thereby forming a color caustic image with color information. Compared to traditional schemes that use color wheels, beam splitters, or liquid crystal modulation to achieve color display, this embodiment utilizes the directional modulation characteristics of the micromirror array module to achieve synchronous transmission of color beams, which can reduce the offset problem between different color light paths and improve the spatial consistency of the color caustic image.

[0100] Furthermore, during the color caustic display process, the control calculation module can establish the target light intensity distribution according to different color channels. For example, for the red, green, and blue color channels, the target light energy distribution of the corresponding color channels can be determined, and the comprehensive deflection parameters of each micromirror unit can be calculated based on the superposition relationship between multiple color channels.

[0101] In one implementation, the control calculation module generates a corresponding multi-channel light intensity matrix based on the color target image and fuses the light intensity information of different color channels to obtain the target spot distribution used to control the micromirror array module. Subsequently, the target deflection angle corresponding to each micromirror unit is calculated based on the target spot distribution, so that the beams of multiple color channels jointly form the target color image in the projection space.

[0102] In this embodiment, the micromirror array-based reflective programmable caustic display device can be further applied to vehicle head-up display systems. Specifically, in vehicle applications, the display device can be installed inside the vehicle dashboard. A display beam is output through an illumination module, and after spatial orientation modulation by the micromirror array module, the resulting caustic image is projected onto the vehicle's windshield or a transparent display component located near the windshield, allowing the driver to obtain display information without looking down.

[0103] For example, in a navigation display scenario, the vehicle navigation system outputs a target image containing information such as road direction, turn prompts, and distance. After acquiring the target image, the control calculation module performs inverse caustics calculation to generate a corresponding set of target spot positions and further calculates the target deflection angle required for each micromirror unit. Based on the calculation results, the drive module controls the micromirror array module to perform continuous angle deflection, so that the light beams reflected by different micromirror units form corresponding virtual display images in front of the vehicle.

[0104] In another application, the display device can be connected to a vehicle driving assistance system. When the vehicle detects a target vehicle ahead, a lane change, or road hazard information, the driving assistance system can generate corresponding display information and send it to the control calculation module. The control calculation module then adjusts the deflection state of the micromirror array module in real time to form a dynamic prompt image in the driver's field of vision.

[0105] Because this embodiment employs a caustic display method based on micromirror array directional modulation, the displayed image does not depend on the pixel arrangement on a fixed display panel. Instead, it is formed by the redistribution of light beams reflected by a large number of micromirror units in space. Therefore, in HUD applications, the optical path structure can be flexibly configured according to the interior spatial layout of the vehicle, and the light field distribution can be dynamically adjusted according to the displayed content.

[0106] Furthermore, when combined with the aforementioned implementation of the electrowetting microlens array, the electrowetting microlens array can be used to further finely adjust the HUD display beam. For example, when the optical path experiences a slight shift due to vibration during vehicle operation, the reflected beam can be compensated by adjusting the refractive state of the electrowetting microlens array, thereby maintaining a high degree of positional stability in the resulting caustic image.

[0107] Furthermore, in this embodiment, the receiving component is positioned on the propagation path of the reflected light beam from the micromirror array module. To meet different display requirements, the receiving component and its projection surface can be any one or a combination of the following: a fixed diffuse reflection screen, an automotive diffuse reflection medium, or a vehicle interior surface with a static diffuse reflection projection surface, used to carry and display two-dimensional continuous caustic grayscale or color images; a vibration receiving component with a high-frequency vibration projection surface, which, driven by a driving mechanism, causes the projection surface to perform high-speed periodic reciprocating motion in the beam propagation direction; or a stacked receiving component with multiple projection surfaces arranged sequentially on the beam propagation path, where each layer of projection surface receives and displays the caustic image components of the corresponding depth section, thereby superimposing to form a three-dimensional caustic stereoscopic display effect.

[0108] Through the above embodiments, this invention utilizes the continuous directional modulation capability of a micromirror array to convert target image information into spatial beam propagation path control information, realizing programmable conversion from image input to light field output. This solution is applicable to vehicle HUDs, augmented reality displays, and other display systems requiring high-degree-of-freedom light field control. The embodiments of this invention have been described in detail above. The various embodiments in the specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section. It should be noted that those skilled in the art can make several improvements and modifications to this invention without departing from the principle of the invention, and these improvements and modifications also fall within the protection scope of the claims of this invention.

Claims

1. A reflective programmable caustic display device based on a micromirror array, characterized in that, include: The lighting module is used to generate and output a beam of light. A micromirror array module is disposed in the optical path of the illumination beam and includes multiple micromirror units distributed in an array. Each micromirror unit has an independent degree of deflection and is used to continuously deflect the illumination beam at an angle within a preset range, so that the illumination beam propagates along a predetermined reflected optical path. The control calculation module is used to acquire the target image and run the caustic inverse calculation process, map the target image to the target light intensity distribution in the projection space, generate a target spot position set based on the target light intensity distribution, determine the target deflection angle corresponding to each micromirror unit according to the target spot position set, and generate corresponding control signals. The driving module is electrically connected to the control calculation module and the micromirror array module, respectively, and is used to drive each of the micromirror units to perform corresponding continuous angle deflection according to the control signal, so that the light beams reflected by each micromirror unit are redistributed and superimposed on the projection surface of the receiving component to form a caustic image with continuous spatial light intensity distribution corresponding to the target image.

2. The reflective programmable caustic display device based on a micromirror array according to claim 1, characterized in that, The illumination module includes a light source and an illumination optical element; the illumination beam generated and output by the illumination module forms a preset angle with the normal direction of the micromirror array module and is incident on the micromirror array module, or is incident perpendicularly on the micromirror array module along the normal direction of the micromirror array module.

3. The reflective programmable caustic display device based on a micromirror array according to claim 2, characterized in that, The light source is any one of a monochromatic laser, a multi-wavelength beam combiner, or a white light-emitting diode; the micromirror array module is a microelectromechanical system (MEMS) micromirror array chip; the driving module is an analog driving circuit; and the control signal is a continuously adjustable analog voltage signal.

4. The reflective programmable caustic display device based on a micromirror array according to claim 1, characterized in that, The micromirror array module also includes a refractive optical field modulation component in its reflection optical path. The refractive optical field modulation component is an electrowetting microlens array, which is used to perform secondary refraction of the reflected beam and modulate the propagation direction of the illumination beam.

5. The reflective programmable caustic display device based on a micromirror array according to claim 1, characterized in that, It also includes a receiving component disposed on the propagation path of the reflected beam of the micromirror array module; the receiving component is any one of a static diffuse reflection screen, a vibration receiving component for realizing three-dimensional caustic display, or a stacked receiving component.

6. A method for a reflective programmable caustic display based on a micromirror array, applied to the reflective programmable caustic display device based on a micromirror array as described in any one of claims 1 to 5, characterized in that, include: Obtain the input target image; The control calculation module performs caustic inverse calculation on the target image, maps it to the target light intensity distribution in the projection space, and generates the corresponding target light spot position set; Based on the global energy constraint relationship between the target spot position set and the initial spot distribution, spot redistribution calculation is performed to obtain the mapping relationship between the initial spot and the target spot; The target reflection direction corresponding to each micromirror unit is calculated based on the mapping relationship and the reflection geometry. Calculate the target deflection angle of each micromirror unit based on the target reflection direction; The target deflection angle of each micromirror unit is converted into a drive control signal; The driving module applies continuous driving parameters to the micromirror array module according to the driving control signal, driving each micromirror unit to undergo corresponding continuous angular deflection, so that the illumination beam is reflected by the micromirror array module and reconstructs the caustic image corresponding to the target image on the projection surface of the receiving component.

7. The method for reflective programmable caustic display based on a micromirror array according to claim 6, characterized in that, The spot redistribution calculation includes: The initial uniform spot grid corresponding to the micromirror unit in the initial undeflected state is extracted, and the energy of the initial uniform spot grid is redistributed based on the global optimal matching principle, so that the spot is redistributed to the target spot position set that matches the energy distribution of the target image while maintaining the total energy constraint.

8. The method for reflective programmable caustic display based on a micromirror array according to claim 6, characterized in that, The step of calculating the target reflection direction corresponding to each micromirror unit based on the mapping relationship and the reflection geometry includes: The spatial propagation direction vector of the reflected light is calculated based on the spatial arrangement coordinates of each micromirror unit and the corresponding target spot position coordinates; the surface normal direction of the micromirror unit is determined by combining the incident light direction vector; and the deflection angle components of each micromirror unit on the orthogonal axis are determined by combining the spatial arrangement constraints of the micromirror array and the incident light path constraints.

9. The method for reflective programmable caustic display based on a micromirror array according to claim 6, characterized in that, The process of converting the deflection angle of each micromirror unit into a drive control signal includes: A pre-calibrated micromirror unit driving response model is obtained. Based on the driving response model, the target deflection angle is segmented and mapped to generate a corresponding driving voltage matrix, which is then output as the driving control signal.

10. The method for reflective programmable caustic display based on a micromirror array according to claim 6, characterized in that, When the target image is a color image, a white light beam is used as the illumination beam. By utilizing the non-dispersion characteristics of the continuous angle deflection reflection of the micromirror unit, the wavelength components of the white light beam maintain a consistent angle modulation characteristic on the spatial reflection path and are synchronously superimposed on the projection surface to form a color caustic image without color distortion.

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