A dual LCD projection device

Abstract

This utility model discloses a dual-LCD projection device, relating to the field of projection display technology, and solves the technical problem that existing projection devices cannot balance projection performance and manufacturing cost. The device includes a first optical path assembly, a second optical path assembly, a beam combiner, and a projection lens. The first optical path assembly includes a first light source, a first illumination lens, a first LCD assembly, and a first imaging lens arranged sequentially along the first optical path. The second optical path assembly includes a second light source, a second illumination lens, a second LCD assembly, and a second imaging lens arranged sequentially along the second optical path. The beam combiner transmits the light emitted from the first optical path assembly and reflects the light emitted from the second optical path assembly. The projection lens receives the light emitted from the beam combiner and forms the projected light. This utility model, through its dual-LCD dual-optical-path beam combiner architecture, effectively improves projection brightness and color gamut performance, simplifies the optical path structure, reduces manufacturing costs, and is suitable for various projection display scenarios.

Description

Technical Field

[0001] This utility model belongs to the field of projection device technology, specifically relating to a dual LCD projection device. Background Technology

[0002] A projector is a display device that projects images or videos onto an imaging medium such as a screen. It is widely used in home audio-visual, office and educational, and commercial display scenarios. With the continuous development of display technology, the market has put forward increasingly higher requirements for the brightness, color gamut, image quality and overall cost performance of projectors.

[0003] Currently, the mainstream projectors on the market are mainly divided into three categories: DLP projectors, single-LCD projectors, and 3LCD projectors. While DLP and 3LCD projectors offer excellent color reproduction and have gained widespread user acceptance, they suffer from a trade-off between performance and cost, failing to simultaneously meet the market demand for high performance and low cost. Single-LCD projectors, limited by the temperature limits of the LCD panel itself, typically use a single white lamp as their light source. Their color gamut coverage and output brightness are relatively low, only meeting the needs of low-end entry-level scenarios and unable to adapt to the performance requirements of mid-to-high-end projection scenarios.

[0004] Dual-LCD projection technology employs a dual-channel light-combining optical path architecture, effectively improving the brightness and color gamut of projection devices while maintaining the same system light output. It is a cost-effective projection technology solution that combines performance and efficiency advantages. However, existing dual-LCD projection solutions still suffer from several technical shortcomings. Inadequate optical path design leads to poor light uniformity and collimation, resulting in uneven beam energy distribution, low light collection efficiency of subsequent optical components, and insufficient overall light energy utilization. Insufficient aberration correction capability in the imaging optical path results in poor clarity, sharpness, and contrast of the projected image, requiring further improvement in image quality. The complex overall optical path layout, requiring a large number of optical components, makes production and debugging difficult, hindering the effective control of manufacturing costs while improving product performance, thus limiting the large-scale application and promotion of dual-LCD projection technology. Utility Model Content

[0005] The technical problem to be solved by this utility model is to overcome the defects of the existing dual LCD projection scheme, which has high cost and insufficient projection quality due to unreasonable optical path setting, and thus provide a dual LCD projection device.

[0006] This utility model provides a dual LCD projection device, including a first optical path assembly, a second optical path assembly, a beam combiner, and a projection lens;

[0007] The first optical path assembly includes a first light source, a first illumination lens, a first LCD assembly, and a first imaging lens arranged sequentially along the first optical path;

[0008] The second optical path assembly includes a second light source, a second illumination lens, a second LCD assembly, and a second imaging lens arranged sequentially along the second optical path;

[0009] The beam combiner is used to transmit the light emitted from the first optical path component and reflect the light emitted from the second optical path component. The projection lens is used to receive the light emitted from the beam combiner to form projected light.

[0010] Furthermore, both the first and second light sources are LED light sources.

[0011] Furthermore, the first light source is a blue light source, and the second light source is a yellow light source.

[0012] Furthermore, the first optical path assembly also includes a first light-diffusing device, which is disposed between the first light source and the first illumination lens.

[0013] Furthermore, the second optical path assembly also includes a second light-diffusing device, which is disposed between the second light source and the second illumination lens.

[0014] Furthermore, both the first illumination lens and the second illumination lens are Fresnel lenses.

[0015] Furthermore, the first imaging lens and the second imaging lens are Fresnel lenses.

[0016] Furthermore, the projection lens is a refractive lens, comprising a first lens, a second lens, and a third lens; the first lens, the second lens, and the third lens are respectively positive optical power, negative optical power, and positive optical power.

[0017] Furthermore, the second optical path component also includes a filter for transmitting light of the color of the second light source.

[0018] Furthermore, the light combining mirror has a dichroic film coated on its internal adhesive surface, and the dichroic film is used to transmit light of the color of the first light source and reflect light of the color of the second light source.

[0019] Beneficial Effects: This invention employs a dual-LCD, dual-optical-path beam combining architecture. Imaging modulation is achieved separately by the first LCD component in the first optical path and the second LCD component in the second optical path. The two beams are combined by a beam combiner and then output through a projection lens. This improves the brightness and color gamut upper limit of the projection while maintaining a constant system light spread. It also effectively controls manufacturing costs while improving projection performance, resulting in high cost-effectiveness. Illumination lenses and imaging lenses are correspondingly set in the dual optical paths. The first and second illumination lenses collimate the emitted beams from the two light sources, improving the light input efficiency of the corresponding LCD components. The first and second imaging lenses then converge the imaging beam emitted from the LCD components, reducing beam transmission loss. Combined with the transmission and reflection beam combining design of the beam combiner, low-loss beam combining of the two beams is achieved, improving the overall light energy utilization and output brightness of the device.

[0020] This invention achieves imaging modulation of different colored lights through the beam splitting paths of the first and second LCD components. The two imaging beams are precisely combined through the transmission and reflection of the beam combiner, effectively reducing crosstalk and improving the color purity and accuracy of the projected image. The design of combining the beams after independent imaging of the two beam paths effectively reduces the aberrations caused by single-path imaging. Combined with the projection lens, this ensures the clarity and uniformity of the projected image. The dual-beam layout of this invention is well-organized, with core optical components arranged sequentially along the corresponding beam paths. The overall structure is simple and compact, eliminating the need for complex multi-beam pixel alignment and debugging, effectively reducing the difficulty of production, assembly, and debugging. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art 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.

[0022] Figure 1 This is a schematic diagram of the main optical path structure of this utility model;

[0023] Figure 2 This is a partial structural schematic diagram of the optical combining mirror of this utility model.

[0024] Explanation of reference numerals in the attached figures:

[0025] 1. First light source; 2. First light homogenizing device; 3. First illumination lens; 4. First LCD assembly; 5. First imaging lens; 6. Second light source; 7. Second light homogenizing device; 8. Filter; 9. Second illumination lens; 10. Second LCD assembly; 11. Second imaging lens; 12. Beam combiner; 13. Projection lens. Detailed Implementation

[0026] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0027] In the description of this application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0028] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0029] Reference Figure 1 and Figure 2 As shown, this embodiment provides a dual LCD projection device, including a first optical path assembly, a second optical path assembly, a beam combiner 12, and a projection lens 13;

[0030] In this embodiment, the first LCD component 4 is a WB-LCD component, and the second LCD component 10 is an RG-LCD component;

[0031] The first optical path assembly includes a first light source 1, a first light-diffusing device 2, a first illumination lens 3, a WB-LCD assembly, and a first imaging lens 5 arranged sequentially along the first optical path;

[0032] The second optical path assembly includes a second light source 6, a second light-diffusing device 7, a filter 8, a second illumination lens 9, an RG-LCD assembly, and a second imaging lens 11 arranged sequentially along the second optical path;

[0033] Among them, WB-LCD component refers to black and white LCD component without color resist setting; RG-LCD component refers to red and green LCD component with red and green resist, but no blue resist.

[0034] The beam combiner 12 is used to transmit the light emitted from the first optical path component and reflect the light emitted from the second optical path component. The projection lens 13 is used to receive the light emitted from the beam combiner 12 to form projected light.

[0035] In a preferred embodiment, the first light source 1 and the second light source 6 are LED light sources. The first light source 1 is a blue light source, and the second light source 6 is a yellow light source.

[0036] The first light-diffusing device 2 is disposed between the first light source 1 and the first illumination lens 3. The second light-diffusing device 7 is disposed between the second light source 6 and the second illumination lens 9.

[0037] The LCD component includes an LCD display liquid crystal and a protective glass, as well as front and rear polarizing films for achieving linearly polarized light output.

[0038] In this embodiment, both the first light-diffusing device 2 and the second light-diffusing device 7 are rectangular conical light chambers with small inlets and large outlets. The inner wall of the light chamber has high reflectivity, and the input light undergoes multiple reflections inside the light chamber to achieve light uniformity, eliminating the texture structure of the LED light source itself, and finally forming a rectangular light spot with uniform energy distribution at the outlet end. Combined with the collimation design of the illumination lens, the beam collection efficiency of the LCD component and subsequent lenses is improved, resulting in high overall light energy utilization.

[0039] The first illumination lens 3 and the second illumination lens 9 are Fresnel lenses. The rectangular light spot formed from the exit end of the light well has high uniformity, but a large divergence angle. Therefore, an illumination lens is provided at the exit of the light well, with the threaded surface of the Fresnel lens facing the LCD assembly to collimate the emitted light beam and improve the light collection efficiency of subsequent components. Preferably, in this embodiment, the focal length of the illumination lens is in the range of 100mm to 120mm.

[0040] The first imaging lens 5 and the second imaging lens 11 are Fresnel lenses, with the threaded surfaces of the Fresnel lenses facing the LCD assembly. The first imaging lens 5 and the second imaging lens 11 can converge the input light and direct it onto the beam combiner 12, thereby achieving light mixing. The imaging lenses are designed to match the LCD assembly, ensuring efficient convergence of linearly polarized light and further improving the sharpness and contrast of the projected image. Preferably, in this embodiment, the focal length of the imaging lenses ranges from 90mm to 110mm.

[0041] In this embodiment, the WB-LCD component, comprising an LCD display liquid crystal, a protective glass, and front and rear polarizing films, receives a collimated beam and outputs linearly polarized light through liquid crystal conversion and polarization. This linearly polarized light is then converged by the first imaging lens 5, passes sequentially through the beam combiner 12 and the projection lens 13, and is finally projected onto the projection surface.

[0042] The light beam emitted by the second light source 6 is first homogenized by the second light homogenizer 7 through the second optical path assembly, and then passes through the filter 8. The filter 8 is used to transmit light of the color of the second light source 6. The filter 8 effectively filters the blue light component carried by the second light source 6, avoiding blue light interference with the purity of the yellow light, thereby improving the color gamut of the system. The yellow light after filtering out the blue light is collimated by the second illumination lens 9 and incident on the RG-LCD assembly. It is then converged by the second imaging lens 11 and arrives at the beam combiner 12.

[0043] In this embodiment, the beam combiner 12 has a dichroic film coated on its internal adhesive surface. This dichroic film transmits light of the color of the first light source 1 and reflects light of the color of the second light source 6. The beam combiner 12 is an adhesive component, and its internal adhesive surface is coated with a yellow-reflecting and blue-transmitting dichroic film. Specifically, the beam combiner has an anti-reflection coating for visible light on the side closer to the second light source 6, and an anti-reflection coating for blue light on the side closer to the first light source 1. The beam combiner 12 features a gradient coating design based on the incident angle and the light source spectrum to ensure efficient transmission of blue light, efficient reflection of yellow light, low beam combining loss, and natural and realistic color transitions.

[0044] The light emitted from the second optical path component first passes through the upper surface of the beam combiner 12 into the adhesive layer, is reflected by the adhesive surface, and is then output from the upper surface; the light emitted from the first optical path component is directly transmitted through the beam combiner 12. The two light paths converge at the beam combiner 12 and enter the projection lens 13 together, ultimately being output to the projection surface. The projection lens 13 is a refractive lens, including a first lens, a second lens, and a third lens; the first lens, the second lens, and the third lens have positive optical power, negative optical power, and positive optical power, respectively, with a focal length range of 90mm to 110mm, which can effectively correct chromatic aberration and field curvature, ensuring image quality.

[0045] This embodiment utilizes a dual-path light-combining architecture with blue light transmission and yellow light reflection via a light-combining mirror 12. This effectively improves projection brightness while maintaining the same system light output. A filter 8 is added to the yellow light path to filter stray blue light, preventing color interference and significantly improving color purity and color gamut performance. By optimizing the optical path layout based on the dual-LCD architecture, the number of optical components and debugging complexity are reduced. This reduces manufacturing costs while maintaining performance, offering a higher cost-performance advantage compared to DLP and 3LCD solutions, making it suitable for mid-to-high-end consumer and commercial projection applications.

[0046] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0047] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A dual LCD projection device, characterized in that, It includes a first optical path assembly, a second optical path assembly, a beam combiner (12), and a projection lens (13). The first optical path assembly includes a first light source (1), a first illumination lens (3), a first LCD assembly (4), and a first imaging lens (5) arranged sequentially along the first optical path. The second optical path assembly includes a second light source (6), a second illumination lens (9), a second LCD assembly (10), and a second imaging lens (11) arranged sequentially along the second optical path. The beam combiner (12) is used to transmit the light emitted from the first optical path component and reflect the light emitted from the second optical path component. The projection lens (13) is used to receive the light emitted from the beam combiner (12) to form projected light. The first light source (1) is a blue light source, and the second light source (6) is a yellow light source; the first LCD component (4) is a black and white LCD component, and the second LCD component (10) is a red and green LCD component.

2. The dual LCD projection device according to claim 1, characterized in that, The first light source (1) and the second light source (6) are LED light sources.

3. The dual LCD projection device according to claim 1, characterized in that, The first optical path assembly further includes a first light-diffusing device (2), which is disposed between the first light source (1) and the first illumination lens (3).

4. The dual LCD projection device according to claim 1, characterized in that, The second optical path assembly further includes a second light-diffusing device (7), which is disposed between the second light source (6) and the second illumination lens (9).

5. A dual LCD projection device according to claim 1, characterized in that, The first illumination lens (3) and the second illumination lens (9) are Fresnel lenses.

6. A dual LCD projection device according to claim 1, characterized in that, The first imaging lens (5) and the second imaging lens (11) are Fresnel lenses.

7. A dual LCD projection device according to claim 1, characterized in that, The projection lens (13) is a refractive lens, including a first lens, a second lens and a third lens; the first lens, the second lens and the third lens are positive optical power, negative optical power and positive optical power, respectively.

8. A dual LCD projection device according to claim 1, characterized in that, The second optical path assembly also includes a filter (8) for transmitting light of the color of the second light source (6).

9. A dual LCD projection device according to claim 1, characterized in that, The light combining mirror (12) has a dichroic film coated on its internal adhesive surface. The dichroic film is used to transmit light of the color of the first light source (1) and reflect light of the color of the second light source (6).

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