Polarization matched electrically controlled lcpg backlight adjustment system, head-up display and control method thereof

Abstract

The application discloses a polarization-matched electrically-controlled LCPG backlight adjusting system, a head-up display and a control method, and the system comprises an illumination unit, a polarization management assembly, an electrically-controlled LCPG deflection assembly, a control unit and a display module, the polarization management assembly and the electrically-controlled LCPG deflection assembly are arranged between the illumination unit and the display module; the polarization management assembly comprises an incident-side polarization conversion unit and an exit-side polarization matching unit, the incident-side polarization conversion unit converts an illumination light beam into a predetermined chiral circularly polarized light; the exit-side polarization matching unit converts the deflected circularly polarized light into linearly polarized light matched with the transmission direction of a rear polarizer; the electrically-controlled LCPG deflection assembly changes the chiral circular polarization of the incident light through a polarization state switching element, so that a liquid crystal polarization grating deflects the light beam to different exit angles; and the control unit controls the exit angle according to a target eyebox position. The application improves the target eyebox brightness and uniformity without increasing the total power of the backlight, and the polarization matching is reliable.

Description

Technical Field

[0001] This invention relates to automotive head-up displays and optical displays, and in particular to a polarization-matched electronically controlled LCPG backlight adjustment system, a head-up display, and a control method thereof. Background Technology

[0002] Head-up displays (HUDs) are widely used in automotive driver assistance systems. The eyebox is the visual area from which the driver can fully observe the virtual image on the HUD. In practice, due to differences in driver height, posture, and seat adjustment, the driver's eyes may be positioned at the upper (upper eyebox), middle (middle eyebox), or lower (lower eyebox). To ensure a usable virtual image is visible from all eye positions, the backlight emission angle distribution of the HUD needs to cover a sufficient vertical angle range while maintaining brightness and uniformity, and controlling power consumption and heat dissipation.

[0003] A common backlight architecture for image generation in head-up displays is as follows: LED chips → dimming assembly → TFT display screen. The light emitted from the LEDs is compressed at the divergence angle by the dimming assembly before illuminating the TFT display screen. The TFT display screen typically has a rear polarizer on the light-incident side, allowing only linearly polarized light from a specific orientation to pass through. This light then passes through a liquid crystal cell and a front polarizer to form an image, which is subsequently projected as a virtual image through a folding mirror, a freeform mirror, and a windshield or combiner.

[0004] In traditional solutions, the light emission angle distribution of LEDs via dimming components is essentially fixed once designed. To accommodate the upper and lower eye boxes, the only options are typically to either increase the divergence angle or maintain a narrow divergence angle: increasing the divergence angle allows for coverage of both eye boxes, but the light energy is thinned across the angular area, resulting in wasted brightness in the central region, or requiring an increase in the total LED power to maintain central brightness, leading to increased power consumption, increased heat dissipation pressure, and exacerbated stray light and lifespan issues; maintaining a narrow divergence angle results in high brightness in the central eye box, but significantly degrades the brightness and uniformity of the upper and lower eye boxes, leading to significant differences in the experience for drivers of different heights. Therefore, existing technologies struggle to simultaneously meet the high brightness and high uniformity requirements of both the central and upper / lower eye boxes without significantly increasing the total light power.

[0005] Other improvement methods also have limitations: fixed beam expanders or uniform light films can improve spatial illumination, but cannot redistribute the angular domain as needed according to the driver's eye position; image rendering gain compensation can brighten at the pixel level, but cannot increase the actual light energy reaching the upper and lower eye boxes, and is prone to introducing noise and color shift; mechanical deflection or adjustable reflectors can change the direction, but there are limitations in terms of size, reliability, response speed, cost, and noise and vibration, which are not conducive to large-scale vehicle applications.

[0006] Furthermore, when using an electronically controlled liquid crystal polarization grating for backlight angular domain adjustment in a head-up display, there is a lack of a complete solution that matches the polarization link between the LED-dimming component-TFT display. Inserting the liquid crystal polarization grating alone will result in reduced efficiency and crosstalk due to polarization mismatch, making it difficult to implement in engineering. Summary of the Invention

[0007] Purpose of the invention: The purpose of this invention is to provide an electrically controlled LCPG backlight adjustment system, head-up display and control method that improves the brightness and uniformity of the target eye box without increasing the total backlight power and has reliable polarization matching.

[0008] Technical solution: The polarization-matched electronically controlled LCPG backlight adjustment system of the present invention includes an illumination unit, a display module and a control unit, wherein a polarization management component and an electronically controlled LCPG deflection component are provided between the illumination unit and the display module;

[0009] The polarization management component includes an incident-side polarization conversion unit and an exit-side polarization matching unit. The incident-side polarization conversion unit is disposed between the illumination unit and the electronically controlled LCPG deflection component, and includes a polarizer and a first quarter-wave plate arranged sequentially along the optical path. The polarizer converts the illumination beam into linearly polarized light, and the first quarter-wave plate converts the linearly polarized light into circularly polarized light with a predetermined chirality. The exit-side polarization matching unit is disposed between the electronically controlled LCPG deflection component and the rear polarizer of the display module, and includes a second quarter-wave plate for converting the circularly polarized light deflected by the electronically controlled LCPG deflection component back into linearly polarized light that matches the transmission direction of the rear polarizer.

[0010] The electronically controlled LCPG deflection assembly includes a polarization state switching element and a liquid crystal polarization grating arranged sequentially along the optical path;

[0011] The control unit is electrically connected to the polarization state switching element. According to the position of the target eye box, the polarization state switching element is controlled to change the circular polarization chirality of the incident light, so that the liquid crystal polarization grating deflects the beam to different exit angles.

[0012] The illumination beam is converted into circularly polarized light of a predetermined chirality by the incident-side polarization conversion unit, enabling the liquid crystal polarization grating to perform efficient single-order diffraction. The light emitted from the liquid crystal polarization grating remains circularly polarized; if directly incident on the back polarizer, approximately half of the light energy is absorbed. Therefore, a second quarter-wave plate is placed between the liquid crystal polarization grating and the back polarizer to restore the circularly polarized light to linearly polarized light parallel to the transmission direction of the back polarizer, improving luminous efficiency and achieving polarization matching. The electrically controlled LCPG deflection assembly changes the incident circular polarization chirality through a polarization state switching element, causing the liquid crystal polarization grating to deflect the beam to different exit angles. The control unit controls the polarization state switching element according to the target eyebox position, thereby guiding light energy to the target eyebox as needed without increasing the total backlight power, improving the brightness and uniformity of the virtual image at the target eyebox.

[0013] Preferably, the polarizer is a linear polarizer or a polarization beam splitter; when the polarizer is a polarization beam splitter, the polarization beam splitter reflects and recovers the orthogonal polarization components.

[0014] A linear polarizer or a polarization beam splitter can be used as the polarizer. When a polarization beam splitter is used, the orthogonal polarization components can be reflected, recovered, and reused, reducing the light energy loss during the polarization process and further improving the system's optical efficiency.

[0015] Preferably, the polarization state switching element is an electronically controlled liquid crystal phase delay device.

[0016] Using an electronically controlled liquid crystal phase delayer as a polarization state switching element, the circular polarization chirality can be quickly changed by utilizing the electro-optic response of the liquid crystal, with a switching time of milliseconds, which is beneficial for rapid response and reliability in automotive applications.

[0017] Preferably, the electronically controlled LCPG deflection assembly includes multiple deflection units arranged sequentially along the optical path. Each deflection unit includes a polarization state switching element and a liquid crystal polarization grating arranged sequentially along the optical path to achieve multiple discrete deflection angles.

[0018] By cascading multiple deflection units, each of which includes a polarization state switching element and a liquid crystal polarization grating, more discrete deflection angles can be achieved, reducing the brightness dip between levels and providing smoother coverage of continuous eye height changes.

[0019] Preferably, the transmission direction of the polarizer is parallel to the polarization direction of the output polarized light domain of the second quarter-wave plate.

[0020] The light emitted from the liquid crystal polarization grating is circularly polarized, while the back polarizer only transmits linearly polarized light in a specific orientation. A second quarter-wave plate is placed between the two to restore the circularly polarized light to linearly polarized light parallel to the transmission direction of the back polarizer, thereby maximizing the light energy transmitted through the back polarizer, improving the overall light efficiency, and avoiding the approximately 50% light energy loss caused by direct incident circularly polarized light on the back polarizer.

[0021] Preferably, the control unit is also configured to adjust the drive current or PWM duty cycle of the lighting unit according to the current deflection state.

[0022] The control unit adjusts the drive current or PWM duty cycle of the lighting unit according to the current deflection state, which can compensate for the residual brightness difference between different deflection states and the oblique incidence angle effect of the TFT display screen, further improving the brightness uniformity at the target eye box.

[0023] Preferably, the lighting unit includes an LED light source and a dimming component, the dimming component being used to compress the divergence angle of the lighting beam.

[0024] The lighting unit uses an LED light source and a dimming component. The dimming component compresses the divergence angle of the LED emitted light to a fixed angle range, providing an approximately unpolarized and well-directional lighting beam for subsequent polarization conversion and angular deflection, which is beneficial to improving light energy utilization.

[0025] The head-up display of the present invention includes a projection optics module and a polarization-matched electronically controlled LCPG backlight adjustment system. The projection optics module is used to project the image beam emitted from the display module to form a virtual image. The control unit controls the state of the polarization switching element according to the position of the target eye box, so that the center angle of the beam emission is oriented towards the position of the target eye box.

[0026] The head-up display integrates a polarization-matched electronically controlled LCPG backlight adjustment system and a projection optics module. The projection optics module projects the modulated image beam as a virtual image, while the backlight system dynamically adjusts the emission center angle according to the position of the target eye box, so that the brightness center of the virtual image moves in the direction perpendicular to the eye box. This improves the brightness and uniformity of the virtual image at the target eye box without increasing the total light power, achieving the effect of light following the eye movement.

[0027] Preferably, the system also includes an eye position detection module for acquiring driver eye position information and providing the control unit with the target eye position.

[0028] The eye position detection module can automatically acquire the driver's eye position information and provide the target eye position to the control unit in real time, realizing closed-loop control and improving the system's adaptability to different driver heights and sitting postures and its ease of use.

[0029] The control method for the head-up display of the present invention includes the following steps:

[0030] S1: The illumination beam is generated by the illumination unit;

[0031] S2: The incident-side polarization conversion unit of the polarization management component converts the light beam before it enters the electrically controlled LCPG deflection component into circularly polarized light with a predetermined chirality.

[0032] S3: Obtain the location of the target eye box;

[0033] S4: Based on the position of the target eyebox, control the state of the polarization switching element so that the beam exit center angle is oriented towards the target eyebox position;

[0034] S5: After the circularly polarized light is deflected by the second quarter-wave plate of the output side polarization matching unit and converted back into linearly polarized light that matches the transmission direction of the rear polarizer, it is incident on the display module and forms a virtual image through the projection optics module.

[0035] Beneficial effects: By coordinating the polarization management component and the electronically controlled liquid crystal polarization grating deflection component, the backlight emission center angle is dynamically adjusted under polarization matching conditions, and the limited light energy is distributed to the target eye box as needed. This improves the brightness and uniformity of the virtual image in the upper and lower eye boxes without increasing the total backlight power. At the same time, it solves the polarization mismatch problem caused by inserting the liquid crystal polarization grating alone. It has the characteristics of fast response, no mechanical movement, compatibility with mainstream backlight structures, and closed-loop adaptation for drivers, and has good prospects for automotive applications. Attached Figure Description

[0036] Figure 1 This is a block diagram illustrating the optical path principle of the polarization-matched electronically controlled LCPG backlight adjustment system of the present invention.

[0037] Figure 2 This is a schematic diagram of the HUD projection optical path system;

[0038] Figure 3 This is a schematic diagram comparing the brightness distribution in the vertical eyebox direction between the traditional fixed divergence angle scheme and the dynamic angle domain redistribution scheme of the present invention.

[0039] Figure 4 This is a schematic diagram of the backlight optical path structure in an embodiment;

[0040] Figure 5 A schematic diagram showing the stacked structure and polarization state changes of the polarization management component and the electronically controlled LCPG deflection component;

[0041] Figure 6 Flowchart of adaptive tracking control for an electronically controlled LCPG backlight adjustment system with polarization matching. Detailed Implementation

[0042] like Figure 1 , 4 As shown in Figure 5, the polarization-matched electrically controlled LCPG backlight adjustment system 10 of the present invention includes an illumination unit, a polarization management component, an electrically controlled LCPG deflection component, a control unit 500, and a display module. The polarization management component includes an incident-side polarization conversion unit and an exit-side polarization matching unit. The incident-side polarization conversion unit, the electrically controlled LCPG deflection component, the exit-side polarization matching unit, and the display module are arranged sequentially along the optical path. The optical path sequence is: LED light source 110 → dimming component 120 → polarizer 210 → first quarter-wave plate 220 → polarization state switching element 310 → liquid crystal polarization grating 320 → second quarter-wave plate 330 → rear polarizer 410 → image generation unit (TFT) 420 → front polarizer 430 → HUD projection optical path 600. The polarizer 210 and the first quarter-wave plate 220 constitute the incident-side polarization conversion unit; the second quarter-wave plate 330 constitutes the exit-side polarization matching unit, located between the liquid crystal polarization grating 320 and the rear polarizer 410.

[0043] The lighting unit includes an LED light source 110 and a dimming component 120. After the light emitted by the LED light source 110 passes through the dimming component 120, the divergence angle is compressed, forming an approximately unpolarized lighting beam, which provides well-directional lighting conditions for subsequent polarization conversion and angular deflection.

[0044] A polarization management component is positioned between the illumination unit and the electronically controlled LCPG deflection component, comprising a polarizer 210 and a first quarter-wave plate 220 arranged sequentially along the optical path. The polarizer 210 converts the illumination beam into linearly polarized light, and the first quarter-wave plate 220 converts the linearly polarized light into circularly polarized light of a predetermined chirality to meet the polarization conditions for efficient single-order diffraction of the liquid crystal polarization grating 320. The polarizer 210 can be a linear polarizer or a polarization beam splitter; when the polarizer 210 is a polarization beam splitter, it reflects and recovers orthogonal polarization components for reuse, reducing light energy loss during polarization and improving system luminous efficiency. The transmission direction of the polarizer 210 is set at approximately 45° to the fast axis of the first quarter-wave plate 220. An exit-side polarization matching unit is positioned between the liquid crystal polarization grating 320 and the rear polarizer 410 of the display module, comprising a second quarter-wave plate 330. The emitted light after deflection by the liquid crystal polarization grating 320 remains circularly polarized; the rear polarizer 410 only transmits linearly polarized light in a specific orientation. If circularly polarized light directly enters the rear polarizer 410, approximately half of the light energy is absorbed, leading to a decrease in luminous efficiency. Therefore, a second quarter-wave plate 330 is provided to restore the circularly polarized light deflected by the liquid crystal polarization grating 320 to linearly polarized light, and to align its polarization direction with the transmission direction of the rear polarizer 410, thereby maximizing the light energy transmitted through the rear polarizer 410, achieving polarization matching, and improving overall luminous efficiency. The fast axis of the second quarter-wave plate 330 is set at approximately 45° relative to the transmission direction of the rear polarizer 410.

[0045] The electrically controlled LCPG deflection assembly includes a polarization state switching element 310 and a liquid crystal polarization grating 320 arranged sequentially along the optical path. The polarization state switching element 310 is specifically an electrically controlled liquid crystal phase retarder, capable of rapidly changing the circular polarization chirality of the incident light using the electro-optic response of the liquid crystal. The liquid crystal polarization grating 320 diffracts the beam to different orders according to the incident circular polarization chirality, ensuring the exit center angle is within... 0° (direct transmission) and The polarization switching element 310 switches between the upper polarization box EB_U, the middle polarization box EB_C, and the lower polarization box EB_L, respectively. The switching time of the polarization switching element 310 can reach the millisecond level, which is beneficial for fast response and reliability in automotive applications.

[0046] The control unit is electrically connected to the polarization state switching element 310. Based on the target eye box position, it generates a drive signal to control the polarization state switching element 310 to change the circular polarization chirality of the incident light, causing the liquid crystal polarization grating 320 to deflect the beam to different exit angles. The control unit can also adjust the drive current of the illumination unit or the PWM duty cycle according to the current deflection state to compensate for residual brightness differences between different deflection states and the oblique incidence viewing angle effect of the TFT display screen, further improving the brightness uniformity at the target eye box.

[0047] The display module includes a rear polarizer 410 and an image generation unit 420, the image generation unit 420 being a TFT display screen. The rear polarizer 410 is located on the light-incident side of the image generation unit 420 and is positioned after the electronically controlled LCPG deflection assembly. The deflected light beam is incident on the display module with polarization conditions matching the transmission direction of the rear polarizer 410, and is then modulated by the rear polarizer 410, the image generation unit 420, and the front polarizer 430 before being emitted as an image beam.

[0048] The second quarter-wave plate 330 is an essential optical element of the outgoing side polarization matching unit. It is positioned between the liquid crystal polarization grating 320 and the back polarizer 410 to convert circularly polarized light back into linearly polarized light that matches the transmission direction of the back polarizer 410. The control unit switches between +θ for the upper eyebox, 0° or direct transmission for the middle eyebox, and -θ for the lower eyebox according to the target eyebox position, guiding the beam to one target eyebox simultaneously. The second quarter-wave plate 330 can be calibrated according to the relationship between the outgoing circular polarization chirality of the current or commonly used deflection state and the axis of the back polarizer 410.

[0049] The electronically controlled LCPG deflection assembly can also employ multiple deflection units arranged sequentially along the optical path. Each deflection unit includes a polarization state switching element 310 and a liquid crystal polarization grating 320 arranged sequentially along the optical path to achieve multiple discrete deflection angles. Circular polarization matching is maintained between each stage, and a compensation waveplate is inserted when necessary. By cascading multiple deflection units, finer step deflection angles can be obtained, reducing brightness dips between stages and more smoothly covering continuous eye height variations; alternatively, only one deflection unit can be used.

[0050] The electrodes of the liquid crystal polarization grating 320 can also be divided into multiple vertical partitions (or not), applying different deflections to the upper and lower regions of the image to compensate for field-related inhomogeneities. Alternatively, a time-division multiplexing approach can be used, with individual frames within a single frame pointing towards the upper and lower eye boxes and synchronized with the backlight, utilizing human eye integration to improve the overall uniformity of perception across the entire eye box.

[0051] When there is a power supply failure, drive failure, or temperature abnormality, the control unit will put the electronically controlled LCPG deflection component into the direct transmission state or the corresponding state of the middle eye box, and may optionally issue an alarm to ensure the basic display function of the head-up display.

[0052] Regarding specific parameters, the single-stage deflection angle θ is approximately 1° to 8°, determined by conversion based on the eye box height, eye point distance, and overall angular magnification. The electronic control switching time is preferably no more than 5 milliseconds, and more preferably no more than 2 milliseconds. The display module uses a TFT display screen. The light source is a monochrome or multi-color LED. The HUD type can be a windshield-type W-HUD, a connector-type C-HUD, an AR-HUD, or a PHUD, etc. Specific values ​​should be calibrated based on the actual vehicle eye box specifications, virtual image distance, and optical tracking results, and do not constitute a limitation on the protection scope.

[0053] like Figure 2 As shown, the head-up display of the present invention includes the aforementioned polarization-matched electronically controlled LCPG backlight adjustment system 10 and a projection optics module 600. The projection optics module 600 projects the image beam emitted from the display module to form a virtual image. The projection optics module 600 includes a reflector 630 or a freeform mirror 620 and a windshield or combiner 610, projecting the image beam emitted from the display module into a virtual image with a predetermined virtual image distance and field of view. Specifically, the image output by the image generation unit 400 is initially reflected by the reflector 630 and then reflected again by the freeform mirror 620 into the windshield or combiner 610 to form a virtual image with a predetermined virtual image distance and field of view.

[0054] When the head-up display is working, the control unit controls the state of the polarization switching element 310 according to the position of the target eye box, so that the beam emission center angle is tilted towards the target eye box position, for example, towards the upper eye box EB_U, the middle eye box EB_C, or the lower eye box EB_L. After the vertical deflection of the backlight main lobe is amplified or mapped by the whole optical path, the brightness center of gravity in the vertical direction of the corresponding eye box is shifted, thereby improving the brightness and uniformity of the target eye box.

[0055] The head-up display may also include an eye position detection module to acquire driver eye position information and provide the target eye box position to the control unit. The eye position detection module can employ a camera or a time-of-flight (ToF) sensor. Automatically acquiring driver eye position information through the eye position detection module enables closed-loop control, improving the system's adaptability to different driver heights and seating postures, and enhancing ease of use.

[0056] Without an eye position detection module, the target eye position can be determined based on seat height memory or driver profile preset position, and manual fine-tuning is provided.

[0057] like Figure 6 As shown, the control method for the head-up display of the present invention includes the following steps:

[0058] Step S1: The illumination unit generates an illumination beam;

[0059] Step S2: Convert the beam before it enters the electrically controlled LCPG deflection component into circularly polarized light of a predetermined chirality using the polarization management component;

[0060] Step S3: Obtain the target eye box position, which is derived from at least one of the eye position detection module, seat position, driver profile, or user settings;

[0061] Step S4: Based on the position of the target eye box, control the state of the polarization state switching element 310 of the electronically controlled LCPG deflection component so that the beam exit center angle is tilted toward the position of the target eye box, for example, toward the upper eye box EB_U, the middle eye box EB_C or the lower eye box EB_L.

[0062] Step S5: The deflected beam is incident on the display module with polarization conditions matching those of the rear polarizer 410, and a virtual image is formed by the projection optical module 600.

[0063] Step S6: Optionally, adjust the drive current or PWM duty cycle of the LED light source 110 according to the deflection state to compensate for the brightness difference between states.

[0064] The mapping relationship between eye position and deflection state can be determined as follows: Let the driver's eye height be h, and the eye height thresholds be h1 and h2 (h1 > h2). When h > h1, the deflection state is +θ, corresponding to the upper eyebox EB_U; when h2 ≤ h ≤ h1, the deflection state is 0° or direct vision, corresponding to the middle eyebox EB_C; when h < h2, the deflection state is -θ, corresponding to the lower eyebox EB_L. h1 and h2 can be calibrated according to the actual vehicle eyebox specifications and virtual image distance.

Claims

1. A polarization-matched electrically controlled LCPG backlight adjustment system, comprising an illumination unit, a display module, and a control unit, characterized in that, A polarization management component and an electronically controlled LCPG deflection component are provided between the lighting unit and the display module; The polarization management component includes an incident-side polarization conversion unit and an exit-side polarization matching unit. The incident-side polarization conversion unit is disposed between the illumination unit and the electronically controlled LCPG deflection component, and includes a polarizer and a first quarter-wave plate arranged sequentially along the optical path. The polarizer converts the illumination beam into linearly polarized light, and the first quarter-wave plate converts the linearly polarized light into circularly polarized light with a predetermined chirality. The outgoing side polarization matching unit is located between the electronically controlled LCPG deflection assembly and the rear polarizer of the display module. It includes a second quarter-wave plate, which is used to convert the circularly polarized light deflected by the electronically controlled LCPG deflection assembly back into linearly polarized light that matches the transmission direction of the rear polarizer. The electronically controlled LCPG deflection assembly includes a polarization state switching element and a liquid crystal polarization grating arranged sequentially along the optical path; The control unit is electrically connected to the polarization state switching element. According to the position of the target eye box, the polarization state switching element is controlled to change the circular polarization chirality of the incident light, so that the liquid crystal polarization grating deflects the beam to different exit angles.

2. The polarization-matched electronically controlled LCPG backlight adjustment system according to claim 1, characterized in that, The polarizer is either a linear polarizer or a polarization beam splitter; when the polarizer is a polarization beam splitter, the polarization beam splitter will reflect and recover the orthogonal polarization components.

3. The polarization-matched electronically controlled LCPG backlight adjustment system according to claim 1, characterized in that, The polarization state switching element is an electronically controlled liquid crystal phase delay device.

4. The polarization-matched electronically controlled LCPG backlight adjustment system according to claim 1, characterized in that, The electronically controlled LCPG deflection assembly includes multiple deflection units arranged sequentially along the optical path. Each deflection unit includes a polarization state switching element and a liquid crystal polarization grating arranged sequentially along the optical path to achieve multiple discrete deflection angles.

5. The polarization-matched electronically controlled LCPG backlight adjustment system according to claim 1, characterized in that, The polarized light emitted from the second quarter-wave plate is parallel to the transmission direction of the rear polarizer.

6. The polarization-matched electronically controlled LCPG backlight adjustment system according to claim 1, characterized in that, The control unit is also configured to adjust the drive current or PWM duty cycle of the lighting unit according to the current deflection state.

7. The polarization-matched electronically controlled LCPG backlight adjustment system according to claim 1, characterized in that, The lighting unit includes an LED light source and a dimming component, which is used to compress the divergence angle of the lighting beam.

8. A head-up display, comprising a projection optics module and a polarization-matched electrically controlled LCPG backlight adjustment system, characterized in that, The projection optics module is used to project the image beam emitted from the display module to form a virtual image; the control unit controls the state of the polarization switching element according to the position of the target eye box, so that the center angle of the beam emission is oriented towards the position of the target eye box.

9. The head-up display according to claim 8, characterized in that, It also includes an eye position detection module for acquiring driver eye position information and providing the target eye position to the control unit.

10. A control method for a head-up display, characterized in that, Includes the following steps: S1: The illumination beam is generated by the illumination unit; S2: The incident-side polarization conversion unit of the polarization management component converts the light beam before it enters the electrically controlled LCPG deflection component into circularly polarized light with a predetermined chirality. S3: Obtain the location of the target eye box; S4: Based on the position of the target eyebox, control the state of the polarization switching element so that the beam exit center angle is oriented towards the target eyebox position; S5: After the circularly polarized light is deflected by the second quarter-wave plate of the output side polarization matching unit and converted back into linearly polarized light that matches the transmission direction of the rear polarizer, it is incident on the display module and forms a virtual image through the projection optics module.

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