Compact Lcos projection system
By combining a light-combining prism, a polarization component, and an LED light source, the problem of excessive size in Lcos optical-mechanical systems is solved, enabling efficient optical imaging of a compact Lcos projection system that meets the space requirements of vehicle-mounted HUDs.
Patent Information
- Application Number
- CN202511262296.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-05
- Publication Date
- 2025-11-11
AI Technical Summary
Existing Lcos optical-mechanical systems suffer from problems such as complex optical paths leading to large size and difficulty in balancing optical efficiency and imaging quality, making it difficult to meet the compact requirements of automotive HUDs.
It adopts a combination structure of beam combining prism, polarization component, converging lens, polarization beam splitter and Lcos device, combined with top-emitting LED light source and T-shaped arrangement, and constructs U-shaped optical path through plane mirror to improve optical efficiency and reduce the size of optomechanical system.
It achieves miniaturization and weight reduction of the Lcos projection system, while improving optical efficiency and imaging quality, with polarization conversion efficiency reaching 80%~90%.
Smart Images
Figure CN120928630A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of vehicle-mounted projection displays, and more particularly to a compact Lcos projection system. Background Technology
[0002] As a core interactive component of smart cockpits, head-up displays (HUDs) significantly improve driving safety and ease of interaction by projecting driving information onto the windshield to form a virtual image. However, with the increasing demands for brightness, resolution, and size in intelligent vehicles, traditional HUD technology faces multiple challenges. Current mainstream projection unit (PGU) technologies include TFT-LCD, DLP, and LCoS. While TFT-LCD has lower costs, it suffers from insufficient brightness and poor contrast. DLP solutions rely on Texas Instruments' DMD chips, which face patent barriers and high costs, and their large size makes them difficult to fit within the compact space requirements of vehicles.
[0003] Liquid crystal on silicon (LCOS) technology, with its high resolution, low power consumption, and reflective optical path design, is considered an ideal solution for automotive head-up displays (HUDs). Its small pixel size and high light utilization are particularly suitable for the wide field-of-view requirements of AR-HUDs, enabling long-distance, wide-field-of-view imaging.
[0004] However, existing Lcos optical engine systems still suffer from several bottlenecks, including complex optical paths leading to large size and difficulties in balancing optical efficiency and image quality. Traditional Lcos optical engines require multiple lenses to converge light to reduce the divergence angle, resulting in excessively large engine sizes that are difficult to fit into the stringent size constraints of automotive spaces. Therefore, achieving miniaturization, weight reduction, and high reliability of Lcos optical engines while ensuring high brightness and high contrast imaging quality has become a pressing technical challenge in the automotive HUD field. Summary of the Invention
[0005] In view of this, this application provides a compact Lcos projection system that solves the problems in the prior art and improves the optical efficiency of the system while ensuring the miniaturization of the Lcos system's optomechanical structure.
[0006] The compact Lcos projection system provided in this application adopts the following technical solution: A compact Lcos projection system includes a light source assembly, a polarization assembly, a converging lens, a polarizing beam splitter, an Lcos device, and a projection lens; The light source assembly includes a light-combining prism, a first light-emitting element, a second light-emitting element, and a third light-emitting element. The light-combining prism has a red light reflecting film and a blue light reflecting film intersecting at 90° inside. The first light-emitting element emits red light that illuminates the light-combining prism along a first direction, passes through the blue light reflecting film, and simultaneously illuminates the reflective surface of the red light reflecting film. The angle between the first direction and the red light emitting film is 45°. The red light emitted by the first light-emitting element is reflected by the red light reflecting film and then emitted along a second direction. The second light-emitting element emits red light along a second direction... Green light is incident on the light combining prism. The green light passes through the red light reflecting film and the blue light reflecting film and is emitted along the second direction. The third light-emitting element emits blue light that is incident on the light combining prism along the third direction and passes through the red light reflecting film and simultaneously irradiates the reflective surface of the blue light emitting film. The blue light emitted by the third light-emitting element is reflected by the blue light reflecting film and is emitted along the second direction. The green light that passes through the red light reflecting film and the blue light reflecting film and is emitted along the second direction, together with the red light and the blue light along the second direction, are combined to form collimated white light. The collimated white light emitted by the light source assembly illuminates the polarization system, and the polarization assembly converts the white light emitted by the light source assembly into P-polarized light before it is emitted. The P-polarized light emitted by the polarization component illuminates the converging lens, and the converging lens, after being modulated and collimated by the P-polarized light beam, enters the polarization beam splitter. The incident and exit surfaces of the polarizing beam splitter are perpendicular. The Lcos device and the incident surface of the polarizing beam splitter are on opposite sides. After the P-polarized light enters the polarizing beam splitter, it passes through the polarizing beam splitter and enters the Lcos device. The Lcos device modulates the light to generate a color optical image and converts the P-polarized light into S-polarized light. The S-polarized light emitted by the Lcos device is directed towards the polarizing beam splitter and reflected within the polarizing beam splitter before exiting to the projection lens.
[0007] Optionally, the first light-emitting element includes a first LED light source and a first TIR collimating lens, the second light-emitting element includes a second LED light source and a second TIR collimating lens, and the third light-emitting element includes a third LED light source and a third TIR collimating lens. The third LED light source emits blue light, and the light emission angle of the first LED light source, the second LED light source, and the third LED light source is 120°. The red light emitted by the first LED light source is collimated into parallel light by the first TIR collimating lens, the green light emitted by the second LED light source is collimated into parallel light by the second TIR collimating lens, and the blue light emitted by the third LED light source is collimated into parallel light by the third TIR collimating lens.
[0008] Optionally, the light source distribution of the first LED light source, the second LED light source, and the third LED light source is Lambertian radiation.
[0009] Optionally, the first LED light source emits red light with a wavelength of 625nm and has a light-emitting area of 1.6mm×1.5mm; the second LED light source emits green light with a wavelength of 520nm and has a light-emitting area of 1.5mm×1.2mm; and the third LED light source emits blue light with a wavelength of 459nm and has a light-emitting area of 1.5mm×1.2mm.
[0010] Optionally, a light homogenizing component is provided between the light source component and the polarization component, the light homogenizing component being used to modulate the collimated white light emitted by the light source component to a uniform level.
[0011] Optionally, the light-diffusing component is a cuboid glass rod, a conical glass rod, a hollow glass rod, or a double-row compound eye lens.
[0012] Optionally, the second direction is perpendicular to the optical axis of the converging lens, and a plane mirror is provided between the exit surface of the polarizing component and the incident surface of the converging lens. The angle between the plane mirror and the second direction is 45°, and the light emitted by the polarizing component enters the converging lens after being reflected by the plane mirror.
[0013] Optionally, the polarizing beam splitter and the plane mirror are parallel, and the direction of the S-polarized light emitted from the polarizing beam splitter is parallel to and opposite to the second direction.
[0014] Optionally, the polarization component includes a PBS prism and a half-wave plate. The PBS prism decomposes the incident light into two perpendicular P-polarized beams and S-polarized beams. The P-beam can pass directly through the PBS prism, while the S-beam is reflected by the PBS prism to the half-wave plate and then deflected as P-polarized beams.
[0015] In summary, this application includes the following beneficial technical effects: The compact Lcos projection system of this application employs LEDs with a top-emitting structure that are highly efficient, small in size, and have a compact heat dissipation structure, arranged in a T-shape on three sides of a light-combining prism. A U-shaped optical engine structure is constructed by reflecting the light path through plane mirrors, maximizing the compression of the optical engine volume. In addition, this application uses a PCS system to improve polarization conversion efficiency, reaching 80%~90%, further improving the system's luminous efficacy while ensuring the miniaturization of the Lcos system. Attached Figure Description
[0016] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0017] Figure 1 This is a schematic diagram of the overall structure of the compact Lcos projection system according to an embodiment of this application; Figure 2 This is a schematic diagram of the structure of the light-combining prism in an embodiment of this application; Figure 3 This is a schematic diagram of the polarization component in an embodiment of this application.
[0018] Explanation of reference numerals in the attached drawings: 1. First light-emitting element; 2. Second light-emitting element; 3. Third light-emitting element; 11. First LED light source; 12. Second LED light source; 13. Third LED light source; 21. First TIR collimating lens; 22. Second TIR collimating lens; 23. Third TIR collimating lens; 30. Beam combining prism; 40. Beam homogenizing component; 50. Polarizing component; 60. Plane mirror; 70. Converging lens; 80. Polarizing beam splitter; 90. Lcos device; 100. Projection lens; 301. Red light reflecting film; 302. Blue light reflecting film; 501. PBS prism; 502. Half-wave plate. Detailed Implementation
[0019] The embodiments of this application will now be described in detail with reference to the accompanying drawings.
[0020] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. This application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0021] It should be noted that various aspects of embodiments within the scope of the appended claims are described below. It will be apparent that the aspects described herein can be embodied in a wide variety of forms, and any particular structure and / or function described herein is merely illustrative. Based on this application, those skilled in the art will understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects set forth herein can be used to implement the device and / or practice the method. Additionally, this device and / or method can be implemented using structures and / or functionalities other than one or more of the aspects set forth herein.
[0022] It should also be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of this application. The illustrations only show the components related to this application and are not drawn according to the number, shape and size of the components in actual implementation. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.
[0023] Furthermore, specific details are provided in the following description to facilitate a thorough understanding of the examples. However, those skilled in the art will understand that the described aspects can be practiced without these specific details.
[0024] This application provides a compact Lcos projection system.
[0025] like Figure 1 , Figure 2 and Figure 3 As shown, a compact Lcos projection system includes a light source assembly, a polarization assembly 50, a converging lens 70, a polarizing beam splitter 80, an Lcos device 90, and a projection lens 100.
[0026] The light source assembly includes a beam combining prism 30, a first light-emitting element 1, a second light-emitting element 2, and a third light-emitting element 3. The beam combining prism 30 is an X-prism, with a reflective film coated at the bonding point. The light-emitting surface of the beam combining prism 30 faces the polarization assembly 50. The first light-emitting element 1 and the third light-emitting element 3 are located on opposite sides of the beam combining prism 30, and the second light-emitting element 2 is located on the side opposite to the light-emitting surface of the beam combining prism 30. The beam combining prism 30 contains a red light reflective film 301 and a blue light reflective film 302 intersecting at 90°. The first light-emitting element 1 emits red light that shines along a first direction onto the beam combining prism 30, passes through the blue light reflective film 302, and simultaneously shines on the reflective surface of the red light reflective film 301. The angle between the first direction and the red light emitting film is 45°. The red light emitted by the first light-emitting element 1 is reflected by the red light reflective film 301 and emitted along a second direction. The second light-emitting element emits green light along the second direction that shines onto the beam combining prism 30. The green light passes through the red light reflector 301 and the blue light reflector 302 and is emitted along the second direction. The third light-emitting element 3 emits blue light that is irradiated on the light combining prism 30 along the third direction and passes through the red light reflector 301 and simultaneously irradiates the reflective surface of the blue light emitting film. The blue light emitted by the third light-emitting element 3 is reflected by the blue light reflector 302 and emitted along the second direction. The green light emitted along the second direction, passing through the red light reflector 301 and the blue light reflector 302, combines with the red light and the blue light along the second direction to form collimated white light.
[0027] The collimated white light emitted by the light source assembly illuminates the polarization system, and the polarization component 50 converts the white light emitted by the light source assembly into P-polarized light before it is emitted.
[0028] The P-polarized light emitted from the polarization component 50 illuminates the converging lens 70, and the converging lens 70, after being modulated and collimated by the P-polarized light beam, enters the polarization beam splitter 80.
[0029] The incident and exit surfaces of the polarizing beam splitter 80 are perpendicular. The Lcos device 90 and the incident surface of the polarizing beam splitter 80 are on opposite sides. After the P-polarized light enters the polarizing beam splitter 80, it passes through the polarizing beam splitter 80 and enters the Lcos device 90. The Lcos device 90 modulates the light to generate a color optical image and converts the P-polarized light into S-polarized light. The S-polarized light emitted from the Lcos device 90 is directed towards the polarizing beam splitter 80 and reflected within the polarizing beam splitter 80 before exiting to the projection lens 100. The projection lens 100 is used to magnify and project the color image generated by the Lcos device 90.
[0030] The compact Lcos projection system of this application uses LEDs with high luminous efficiency, small size and compact heat dissipation structure with top-emitting structure, which are arranged in a T-shape on three sides of the light combining prism 30 to reduce the space occupied by the light source components and reduce the volume of the Lcos projection system. The polarization component 50 improves the light utilization rate of the projection system, so that more light energy can be effectively utilized.
[0031] The first light-emitting element 1 includes a first LED light source and a first TIR collimating lens 21; the second light-emitting element 2 includes a second LED light source and a second TIR collimating lens 22; and the third light-emitting element 3 includes a third LED light source 13 and a third TIR collimating lens 23. The third LED light source 13 emits blue light. The emission angle of the first LED light source, the second LED light source, and the third LED light source 13 is 120°, and the optical efficiency of the TIR collimating lens reaches over 90%.
[0032] The red light emitted by the first LED light source is collimated into parallel light by the first TIR collimating lens 21, the green light emitted by the second LED light source is collimated into parallel light by the second TIR collimating lens 22, and the blue light emitted by the third LED light source 13 is collimated into parallel light by the third TIR collimating lens 23.
[0033] The light source distribution of the first LED light source, the second LED light source, and the third LED light source 13 is Lambert radiation.
[0034] The first LED light source emits red light with a wavelength of 625nm and has a light-emitting area of 1.6mm×1.5mm; the second LED light source emits green light with a wavelength of 520nm and has a light-emitting area of 1.5mm×1.2mm; the third LED light source 13 emits blue light with a wavelength of 459nm and has a light-emitting area of 1.5mm×1.2mm.
[0035] The polarization component 50 employs a PCS system, including a PBS prism 501 and a half-wave plate 502. Multiple strip-shaped PBS prisms 501 are bonded together in the PCS system, with a polarizing film coated at the bonding interface, allowing transmission of P-polarized light and reflection of S-polarized light. The PBS prism 501 decomposes the incident light into two perpendicular beams of P-polarized and S-polarized light. The P-light can pass directly through the PBS prism 501, while the S-light is reflected by the PBS prism 501 to the half-wave plate 502 and then depolarized into P-polarized light. The polarization component 50 using the PCS system improves polarization conversion efficiency to 80% to 90%.
[0036] In this embodiment, the converging lens 70 is a convex lens used to modulate and collimate the linearly polarized light deflected by the PCS system.
[0037] A light-homing component 40 is further provided between the light source component and the polarization component 50. The light-homing component 40 is used to uniformly modulate the collimated white light emitted by the light source component. The light-homing component 40 is a cuboid glass rod, a conical glass rod, a hollow glass rod, or a double-row compound eye lens. In the embodiment of this application, the light-homing component 40 is a double-row compound eye lens.
[0038] The second direction is perpendicular to the optical axis of the converging lens 70, and a plane mirror 60 is provided between the exit surface of the polarizing component 50 and the incident surface of the converging lens 70. The angle between the plane mirror and the second direction is 45°. The light emitted from the polarizing component 50 enters the converging lens 70 after being reflected by the plane mirror 60. The polarizing beam splitter 80 is parallel to the plane mirror 60, and the direction of the S-polarized light emitted from the polarizing beam splitter 80 is parallel to and opposite to the second direction.
[0039] By constructing a U-shaped optical path structure using a 60-degree plane mirror, the size of the projection system can be further reduced.
[0040] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.
Claims
1. A compact Lcos projection system, characterized in that, It includes a light source assembly, a polarization assembly (50), a converging lens (70), a polarizing beam splitter (80), an Lcos device (90), and a projection lens (100); The light source assembly includes a light-combining prism (30), a first light-emitting element (1), a second light-emitting element (2), and a third light-emitting element (3). The light-combining prism (30) has a red light reflector (301) and a blue light reflector (302) intersecting at 90° inside. The first light-emitting element (1) emits red light that illuminates the light-combining prism (30) along a first direction, passes through the blue light reflector (302), and simultaneously illuminates the reflective surface of the red light reflector (301). The angle between the first direction and the red light emitting film is 45°. The red light emitted by the first light-emitting element (1) is reflected by the red light reflector (301) and emitted along a second direction. The second light-emitting element emits... Green light, along the second direction and illuminating the light combining prism (30), passes through the red light reflecting film (301) and the blue light reflecting film (302) and is emitted along the second direction. The third light-emitting element (3) emits blue light that is illuminating the light combining prism (30) along the third direction and passes through the red light reflecting film (301) and simultaneously illuminating the reflective surface of the blue light emitting film. The blue light emitted by the third light-emitting element (3) is reflected by the blue light reflecting film (302) and emitted along the second direction. The green light that passes through the red light reflecting film (301) and the blue light reflecting film (302) and is emitted along the second direction combines with the red light along the second direction and the blue light along the second direction to form collimated white light. The collimated white light emitted by the light source assembly illuminates the polarization system, and the polarization assembly (50) converts the white light emitted by the light source assembly into P-polarized light before emitting it. The P-polarized light emitted from the polarization component (50) illuminates the converging lens (70), and the converging lens (70) is collimated by the beam modulation of the P-polarized light and then enters the polarization beam splitter (80). The incident and exit surfaces of the polarizing beam splitter (80) are perpendicular. The Lcos device (90) and the incident surface of the polarizing beam splitter (80) are on opposite sides. The P-polarized light enters the polarizing beam splitter (80) and passes through the polarizing beam splitter (80) into the Lcos device (90). The Lcos device (90) modulates the light to generate a color optical image and converts the P-polarized light into S-polarized light. The S-polarized light emitted by the Lcos device (90) is directed towards the polarizing beam splitter (80) and reflected within the polarizing beam splitter (80) before exiting to the projection lens (100).
2. The compact Lcos projection system according to claim 1, characterized in that, The first light-emitting element (1) includes a first LED light source and a first TIR collimating lens (21), the second light-emitting element (2) includes a second LED light source and a second TIR collimating lens (22), and the third light-emitting element (3) includes a third LED light source (13) and a third TIR collimating lens (23). The third LED light source (13) emits blue light, and the light emission angle of the first LED light source, the second LED light source and the third LED light source (13) is 120°. The red light emitted by the first LED light source is collimated into parallel light by the first TIR collimating lens (21), the green light emitted by the second LED light source is collimated into parallel light by the second TIR collimating lens (22), and the blue light emitted by the third LED light source (13) is collimated into parallel light by the third TIR collimating lens (23).
3. The compact Lcos projection system according to claim 2, characterized in that, The light source distribution of the first LED light source, the second LED light source and the third LED light source (13) is Lambert radiation.
4. The compact Lcos projection system according to claim 3, characterized in that, The first LED light source emits red light with a wavelength of 625nm and has a light-emitting area of 1.6mm×1.5mm; the second LED light source emits green light with a wavelength of 520nm and has a light-emitting area of 1.5mm×1.2mm; the third LED light source (13) emits blue light with a wavelength of 459nm and has a light-emitting area of 1.5mm×1.2mm.
5. The compact Lcos projection system according to claim 1, characterized in that, A light-diffusing component (40) is also provided between the light source component and the polarization component (50), and the light-diffusing component (40) is used to modulate the collimated white light emitted by the light source component to be uniform.
6. The compact Lcos projection system according to claim 5, characterized in that, The light-diffusing component (40) is a cuboid glass rod, a conical glass rod, a hollow glass rod, or a double-row compound eye lens.
7. The compact Lcos projection system according to claim 1, characterized in that, The second direction is perpendicular to the optical axis of the converging lens (70), and a plane mirror (60) is provided between the exit surface of the polarizing component (50) and the incident surface of the converging lens (70). The angle between the plane mirror and the second direction is 45°. The light emitted from the polarizing component (50) enters the converging lens (70) after being reflected by the plane mirror (60).
8. The compact Lcos projection system according to claim 7, characterized in that, The polarizing beam splitter (80) and the plane mirror (60) are parallel, and the direction of the S-polarized light emitted from the polarizing beam splitter (80) is parallel to and opposite to the second direction.
9. The compact Lcos projection system according to claim 1, characterized in that, The polarization component (50) includes a PBS prism (501) and a half-wave plate (502). The PBS prism (501) decomposes the incident light into two perpendicular P-polarized beams and S-polarized beams. The P-beam can pass directly through the PBS prism (501), while the S-beam is reflected by the PBS prism (501) to the half-wave plate (502) and then deflected into P-polarized beams.