A two-panel LCD projection device and system

Abstract

The application relates to the projection technical field, and provides a two-piece type LCD projection device which is used for improving color saturation and comprises the following steps: yellow light emitted by a first group of projection light sources is converted into red and green light through a red-green LCD screen, and then the red and green light is imaged onto a screen through a projection lens; a second group of projection light sources emit alternately flashing blue light and green light, the blue light and the green light are gathered through an aspherical lens, reflected to a rear Fresnel lens through a reflecting mirror, changed into polarized light through a second polaroid, and then incident to a black-white LCD screen, the black-white LCD screen receives the alternately flashing blue light and green light and alternately displays blue-green images, wherein the blue-green image display frequency is consistent with the flashing frequency of the second group of projection light sources, the blue-green images are irradiated to a two-phase color mirror after passing through a second front Fresnel lens, the two-phase color mirror reflects the alternately flashing blue light and the green light with a wavelength higher than a preset value, the rest light is transmitted, the reflected light is transmitted through the projection lens and imaged onto the screen, and the imaging is aligned with the imaging of a first light path imaging system.

Description

Technical Field

[0001] This application relates to the field of projection technology, and in particular to a two-panel LCD projection device and projection system. Background Technology

[0002] Liquid Crystal Display (LCD), simply put, works by placing liquid crystals between two parallel glass panes. Numerous tiny vertical and horizontal wires connect the glass panes, controlling the orientation of rod-shaped crystal molecules by applying current, thus refracting light to create an image. Current LCD-based projection technologies include single-panel LCD projection, two-panel LCD projection (2LCD), and three-panel LCD projection (3LCD).

[0003] The inventors discovered that in some 2LCD projection devices, in order to increase brightness, the color saturation of the projected image is poor. Summary of the Invention

[0004] The purpose of this application is to provide a two-panel LCD projection device and projection system to solve the technical problem of poor color saturation.

[0005] To achieve the above objectives, the technical solution adopted in this application is as follows:

[0006] A two-panel LCD projection device, comprising:

[0007] First optical path imaging system and second optical path imaging system;

[0008] The first optical path imaging system is used to convert the yellow light emitted by the first group of projection light sources 1 into red and green light through the red and green LCD screen 6, and then image it onto the screen through the projection lens 14.

[0009] The second optical path imaging system includes a second set of projection light sources 8, an aspherical lens 9, a reflector 10, a rear Fresnel lens 11, a second front Fresnel lens 7.2, a second polarizer 4.2, a black and white LCD screen 12, the dichroic mirror 13, and a projection lens 14.

[0010] In the second optical path imaging system, the second group of projection light sources 8 emits alternating flashing blue-green light, which is focused by the aspherical lens 9, reflected by the mirror 10, and then converted into second polarized light by the second polarizer 4.2 before being incident on the monochrome LCD screen 12. The monochrome LCD screen 12 receives the alternating flashing blue-green light and displays blue-green images alternately, wherein the display frequency of the blue-green images is consistent with the flashing frequency of the second group of projection light sources 8. After passing through the second front Fresnel lens 7.2, the light is incident on the dichroic mirror 13. The dichroic mirror 13 reflects the alternating blue-green light incident through the second front Fresnel lens 7.2, and transmits the reflected light through the projection lens 14 to form an image on the screen, which is aligned with the image of the first optical path imaging system.

[0011] Furthermore, the red-green LCD screen 6 is used to receive red, green, and blue images and to display the red and green images therein.

[0012] Furthermore, the first group of projection light sources 1 is a blue LED light source coated with yellow phosphor, and the second group of projection light sources 1 is a blue-green mixed LED light source.

[0013] Furthermore, the first optical path imaging system also includes an optical chamber 2, a rear Fresnel lens 3, a first polarizer 4.1, a blue light filter 5, a first front Fresnel lens 7.1, a dichroic mirror 13, and a projection lens 14;

[0014] In the first optical path imaging system, the yellow light emitted by the first group of projection light sources 1 passes through the light chamber 2 and then illuminates the rear Fresnel lens 3. After passing through the first polarizer 4.1, it becomes first polarized light. The first polarized light passes through the blue light filter 5 to filter out the blue light portion of the first polarized light, forming target yellow light. The target yellow light is focused by the red-green LCD screen 6 and the first front Fresnel lens 7.1 to form red-green light. The red-green light passes through the dichroic mirror 13 and is imaged onto the screen by the projection lens 14.

[0015] Furthermore, in the first optical path imaging system, the yellow light emitted by the first group of projection light sources 1 passes through the light chamber 2 and then illuminates the rear Feuerbach 3 to form a parallel first beam.

[0016] Furthermore, in the second optical path imaging system, the alternating blue-green light emitted by the second group of projection light sources 8 is focused by the aspherical lens 9, and then illuminated by the reflector 10 onto the rear Fresnel lens 11 to become a second beam perpendicular to the first beam.

[0017] Furthermore, the first polarized light is P-polarized light, and the second polarized light is S-polarized light.

[0018] Furthermore, after the red and green light passes through the dichroic mirror 13, light with a wavelength greater than or equal to 480nm is transmitted, while light with a wavelength less than 480nm is reflected. When the dichroic mirror 13 reflects alternating blue and green light that passes through the second front Fresnel lens 7.2, light with a wavelength less than 480nm is reflected, light with a wavelength of 540-560nm is reflected, and light with other wavelengths is transmitted.

[0019] Furthermore, the angle between the red-green LCD screen 6 and the black-and-white LCD screen 12 is 90°.

[0020] A two-panel LCD projection system, comprising a two-panel LCD projection device as described in any of the preceding claims and a signal input device, wherein the signal input device is electrically connected to the red-green LCD screen 6 and the black-and-white LCD screen 12 of the two-panel LCD projection device, respectively, wherein:

[0021] The signal input device is used to synchronously transmit red, green, and blue image signals to the red-green LCD screen 6 and the black-and-white LCD screen 12; the signal input device is also used to input the image to be projected.

[0022] The red-green LCD screen 6 parses and displays the red-green image signal from the received red-green-blue image signal;

[0023] The monochrome LCD screen 12 is used to parse and display the blue-green image signal from the received red-green-blue image signal.

[0024] The aforementioned solution includes two imaging paths. One path converts the yellow light emitted by the first projection light source 1 into red-green light through the red-green LCD screen 6, and then images it onto the screen through the projection lens 14. The other path reflects alternating blue-green light, transmits the reflected light through the projection lens 14, and images it onto the screen, aligning it with the image from the first optical path imaging system to achieve imaging. In this application, through a multi-layer design, two optical paths are formed, both of which contain green light. The green light in the first optical path system passes through, increasing brightness, while the second optical path system reflects the higher wavelength green light for imaging, increasing color saturation. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this application, 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.

[0026] Figure 1This is a schematic diagram of a two-panel LCD projection device with a light filtering function according to an embodiment of this application;

[0027] Figure 2 This is a schematic diagram of the light spectrum emitted by the blue LED light source in this application;

[0028] Figure 3 This is a schematic diagram of the transmittance of the LCD screen in this application;

[0029] Figure 4 This is a schematic diagram of the S-light transmission spectrum of the dichroic mirror in this application;

[0030] Figure 5 This is a schematic diagram of the transmission spectrum of the P-light from the dichroic mirror in this application.

[0031] The following are the labeling elements in the figure:

[0032] 1-First projection light source; 2-Light chamber; 3-Rear Fresnel lens; 4.1-First polarizer; 4.2-Second polarizer; 5-Blue light filter; 6-Red-green LCD screen; 7.1-First front Fresnel lens; 7.2-Second front Fresnel lens; 8-Second projection light source; 9-Aspherical lens; 10-Reflector; 11-Rear Fresnel lens; 12-Black and white LCD screen; 13-Dichromatic mirror; 14-Projection lens. Detailed Implementation

[0033] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0034] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0035] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0036] Furthermore, 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 technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0037] Example 1 - A Two-Piece LCD Projection Device

[0038] The inventors discovered that in some 2LCD projection devices, in order to improve brightness, the color saturation of the projected image is poor. To solve this technical problem, this application provides a two-panel LCD projection device with high color saturation.

[0039] In one embodiment, such as Figure 1 As shown, a two-panel LCD projection device is provided, comprising:

[0040] First optical path imaging system and second optical path imaging system;

[0041] The first optical path imaging system is used to convert the yellow light emitted by the first group of projection light sources 1 into red and green light through the red and green LCD screen 6, and then image it onto the screen through the projection lens 14.

[0042] The second optical path imaging system includes a second set of projection light sources 8, an aspherical lens 9, a reflector 10, a rear Fresnel lens 11, a second front Fresnel lens 7.2, a second polarizer 4.2, a monochrome LCD screen 12, a dichroic mirror 13, and a projection lens 14.

[0043] In the second optical path imaging system, the second set of projection light sources 8 emits alternating flashing blue and green light, which is focused by the aspherical lens 9, reflected by the mirror 10, and then passed through the rear Fresnel lens 11. The light is then converted into second polarized light by the second polarizer 4.2 and incident on the black and white LCD screen 12. The black and white LCD screen 12 receives the alternating flashing blue and green light and displays blue and green images alternately. The display frequency of the blue and green images is consistent with the flashing frequency of the second set of projection light sources 8. The light then passes through the second front Fresnel lens 7.2 and illuminates the dichroic mirror 13. The dichroic mirror 13 reflects the alternating blue light and the green light with a wavelength higher than the preset value that have passed through the second front Fresnel lens 7.2. The remaining light passes through and is projected onto the screen through the projection lens 14, and is aligned with the image of the first optical path imaging system.

[0044] In this embodiment, two imaging paths are included. One path converts the yellow light emitted by the first set of projection light sources 1 into red and green light through the red-green LCD screen 6, and then images it onto the screen through the projection lens 14. The other path reflects alternating blue and green light, transmits the reflected light through the projection lens 14, and images it onto the screen, aligning it with the imaging of the first optical path imaging system to achieve imaging. In this application, through a multi-layer design, two optical paths are formed, both of which contain green light. The green light in the first optical path system passes through, which can improve brightness. The second optical path system reflects the high-wavelength green light for imaging, which can improve color saturation.

[0045] Through research, the inventors discovered that, in conjunction with the above embodiments, in the red-green direction, i.e., in the first optical path imaging system, there is a phenomenon of excessively high screen temperature of the LCD screen 6 in the red-green direction. This is because some blue light used is often not converted into red-green light, and only the red-green spectrum portion of the LCD 6 in the red-green direction is transmitted. Therefore, the blue light portion is completely absorbed and converted into heat after reaching the red-green LCD screen 6, resulting in excessively high temperature of the LCD screen 6 in the red-green direction, which reduces the LCD screen's ability to withstand light intensity and leads to low brightness.

[0046] To address this technical problem, the applicant further optimized the first optical path imaging system to resolve the aforementioned technical issue that reduces the LCD screen's ability to withstand light intensity, resulting in low brightness.

[0047] Specifically, such as Figure 1 As shown, in one embodiment, the first optical path imaging system further includes an optical chamber 2, a rear Fresnel lens 3, a first polarizer 4.1, a blue light filter 5, a first front Fresnel lens 7.1, a dichroic mirror 13, and a projection lens 14;

[0048] In the first optical path imaging system, the yellow light emitted by the first group of projection light sources 1 passes through the light chamber 2 and then illuminates the rear Fresnel lens 3. After passing through the first polarizer 4.1, it becomes first polarized light. The first polarized light passes through the blue light filter 5 to filter out the blue light portion of the first polarized light, forming the target yellow light. The target yellow light is focused by the red-green LCD screen 6 and the first front Fresnel lens 7.1 to form red-green light. The red-green light passes through the dichroic mirror 13 and is imaged onto the screen through the projection lens 14.

[0049] like Figure 2 and Figure 3 As shown, Figure 2 This is a schematic diagram of the light spectrum emitted by a blue LED light source. Figure 3This is a schematic diagram of the transmittance of a red-green LCD screen. It can be seen that the red-green LCD screen transmits light wavelengths above 480nm, while the blue LED light source still has a large light energy output below 480nm. This part of the light irradiating the red-green LCD screen will generate a lot of heat, thereby increasing the temperature of the red-green LCD screen and easily reducing its lifespan. Therefore, the two-piece LCD projection device provided in this application can effectively reduce the temperature of the red-green LCD screen and increase its lifespan. While reducing the temperature, it can also further increase the brightness of the projection light source to improve the overall projection brightness.

[0050] That is, in the first optical path imaging system, the light becomes first polarized light after passing through the first polarizer 4.1. The first polarized light is filtered by the blue light filter 5 to filter out the blue light portion of the first polarized light, forming the target yellow light. After filtering out the invalid blue light, the light passes through the red-green LCD screen 6, which can effectively reduce the amount of useless blue light shining on the red-green LCD screen 6, reduce or avoid the excess heat generated by the red-green LCD screen 6 receiving useless blue light, thereby reducing the temperature of the red-green LCD screen 6. This can improve the service life of the red-green LCD screen 6. For this reason, it can also increase the light intensity that the red-green LCD screen 6 can withstand. Finally, by increasing the brightness of the first projection light source 1 in the two-piece LCD projection device, the projection brightness of the two-piece LCD projection device with the light filtering function can be improved, thus improving the brightness while ensuring high saturation.

[0051] In one embodiment, the first group of projection light sources 1 is a blue LED light source coated with yellow phosphor, and the second group of projection light sources 1 is a blue-green mixed LED light source.

[0052] This embodiment clarifies the implementation of the first group of projection light sources 1. In this method, it should be noted that since the first optical path imaging system focuses the desired yellow light through the red-green LCD screen 6 and the first front Fresnel lens 7.1 to form red-green light, the first group of projection light sources 1 can be yellow LED light sources. However, direct yellow LED light sources have low light conversion efficiency, poor temperature stability, and are too expensive. In this embodiment, a blue LED light source coated with yellow phosphor is used as the first group of projection light sources 1. The blue light emitted by the blue LED is excited into yellow light after passing through the phosphor, which effectively improves the light conversion efficiency. Furthermore, as an example, the second group of projection light sources 8 is clarified as a blue-green mixed LED light source.

[0053] It is also worth noting that using a blue LED light source coated with phosphor can achieve a relatively high conversion efficiency between red and green, however, as... Figure 2Analysis shows that, by analyzing the emission spectrum of the blue LED light source, it is found that, due to the efficiency of the phosphor, a significant portion of the blue light generated by the blue LED light source and phosphor is not converted into red and green light. The blue portion is completely absorbed and converted into heat upon reaching the LCD. In this embodiment, by placing the blue light filter 5 between the first polarizer 4.1 and the red and green LCD screen 6, the portion of light transmitted through the first polarizer 4.1 can be blocked by the blue light filter 5, thereby reducing the temperature on the rear red and green LCD screen 6. This further ensures the lifespan of the projection method using blue LED light source coated with phosphor and enhances the subsequent brightness, thus improving the overall projection brightness.

[0054] For example, in the first optical path imaging system, the first polarized light passes through a blue light filter 5 to filter out the blue light portion of the first polarized light with wavelengths below 480nm, forming a useful target yellow light with wavelengths above 480nm, which has higher brightness than a monochromatic LED light source at the same power.

[0055] In one embodiment, in the first optical path imaging system, the yellow light emitted by the first group of projection light sources 1 passes through the light chamber 2 and then illuminates the rear Flynn mirror 3, forming a parallel first beam. It should be noted that the first beam formed on the rear Flynn mirror 3 can also be nearly parallel light; no specific limitation is made. In this embodiment, the first polarized light is incident on the first polarizer in a parallel or nearly parallel manner, reducing light refraction and effectively utilizing the incident light.

[0056] In one embodiment, in the second optical path imaging system, the blue diverging light emitted by the second set of projection light sources 8 is focused by the aspherical lens 9, and then illuminated by the reflector 10 to the rear Fresnel lens 11, becoming a second beam perpendicular to the first beam. After being reflected by the reflector 10 to the rear Fresnel lens 11, it enters the second polarizer 4.2 in a vertical manner, which can also reduce light refraction and effectively utilize the incident light.

[0057] In one embodiment, the angle between the red-green LCD screen 6 and the black-and-white LCD screen 12 is 90°. Setting the angle between the red-green LCD screen 6 and the black-and-white LCD screen 12 to 90° facilitates the placement of the dichroic mirror 13. For example, the dichroic mirror 13 is placed between the first front Fresnel lens 7.1 and the second front Fresnel lens 7.2, and the angle between the dichroic mirror 13 and the first front Fresnel lens 7.1 and the second front Fresnel lens 7.2 is 45°. In this way, the overall structure of the two-panel LCD projection device with filtering function can be made compact, and the dichroic mirror 13 can completely reflect the red and green light focused by the first front Fresnel lens 7.1 and the blue wavelength light irradiated by the second front Fresnel lens 7.2, thus ensuring the imaging quality of the two optical path systems.

[0058] In one embodiment, the first polarized light is P-polarized light and the second polarized light is S-polarized light.

[0059] In this embodiment, polarization optimization is also performed in the horizontal and vertical directions, forming P-light in the horizontal direction and S-light in the vertical direction. As an example, ... Figure 4 and Figure 5 As shown, in this embodiment, the coating pattern of the dichroic mirror is changed so that after red and green light passes through the dichroic mirror 13, light with wavelengths greater than or equal to 480nm is transmitted, while light with wavelengths less than 480nm is reflected. When the dichroic mirror 13 reflects alternating blue and green light passing through the second front Fresnel lens 7.2, light with wavelengths less than 480nm is reflected, light with wavelengths between 540 and 560nm is reflected, and light of other wavelengths is transmitted. In this embodiment, since there is green light in both the horizontal and vertical directions, it is necessary to perform PS processing on the light in the horizontal and vertical directions to ensure that green light enters the projection lens for imaging.

[0060] In one embodiment, the red-green LCD screen 6 is used to receive red, green and blue images and to display the red and green images therein.

[0061] In this embodiment, the two-panel LCD projection device directly receives the red, green, and blue images from the signal input device through the red and green LCD screens. These red, green, and blue images are the images to be projected. The red and green LCD screens display the color images by distinguishing the signals internally. Specifically, the first set of LCDs is used to display the red and green images, without needing to process the color signals before inputting them into their respective LCD screens. This reduces signal processing time or the need for signal processing devices such as drivers, significantly improving display efficiency and cost.

[0062] In one embodiment, the two-panel LCD projection device further includes a projection controller, which is used to monitor the display brightness of the aligned projection image result and the temperature of the red and green LCD screens in real time; when the display brightness is lower than a preset brightness and the temperature of the red and green LCD screens is lower than a first preset temperature, the luminous brightness of the first group of projection light sources 1 is increased according to the temperature.

[0063] In this embodiment, the projection process is optimized and controlled using the two-piece LCD projection device provided in this application embodiment. This embodiment can detect the display brightness of the aligned projection image result and the temperature of the red-green LCD screen 6 in real time through light and temperature sensors. The parameters detected by the sensors are fed back to the projection controller. After obtaining the display brightness and temperature, the projection controller will make a comprehensive judgment. Specifically, this application embodiment sets two temperature thresholds, namely a first preset temperature and a second preset temperature. The setting of these two preset temperatures is related to the projection system and can be determined experimentally. A preset brightness is also set, which can also be obtained experimentally. The projection controller will determine the relationship between the display brightness and the preset brightness, and the relationship between the temperature of the red-green LCD screen 6 and the first and second preset temperatures. When the display brightness is lower than the preset brightness and the temperature of the red-green LCD screen 6 is lower than the first preset temperature, the luminous brightness of the first group of projection light sources 1 is increased according to the temperature.

[0064] In this embodiment, the special optical path transmission setting of the two-piece LCD projection device is first used to improve the light intensity receiving capability of the red and green LCD screen 6. On this basis, the light intensity of the first set of projection light sources 1 with adjustable light intensity is set. When the display brightness is lower than the preset brightness and the temperature of the red and green LCD screen 6 is lower than the first preset temperature, it indicates that the display brightness is insufficient. However, the light intensity receiving capability of the subsequent red and green LCD screen 6 is improved through projection by the optical path system, and the red and green LCD screen will remain relatively low. Therefore, when the temperature of the red and green LCD screen 6 is lower than the first preset temperature, the light intensity of the first set of projection light sources 1 can be increased according to the temperature.

[0065] For example, the first projection light source 1 is a blue LED light source with adjustable brightness. The blue LED light source is connected to the projection controller. When the temperature of the color LCD screen 6 is lower than a first preset temperature and the display brightness is lower than a preset brightness, the brightness of the blue LED light source is increased according to the detected temperature of the color LCD screen. The brightness is provided by increasing the power of the blue LED light source. The method of increasing the brightness can be based on the temperature gradient, and the brightness of the blue LED light source can be changed accordingly. The specific method is not limited.

[0066] It is worth noting that in this embodiment, while monitoring the temperature of the red and green LCD screen 6, the display brightness is also monitored. By combining these two aspects, the filtering effect of the set optical path system can be monitored and the projection imaging quality can be guaranteed, taking into account both brightness and temperature.

[0067] In one embodiment, after real-time monitoring of the display brightness of the projected image after alignment and the temperature of the monochrome LCD screen, the projection controller maintains the original luminous brightness of the first group of projection light sources 1 when the display brightness is higher than a preset brightness and the temperature of the red-green LCD screen 6 is lower than a second preset temperature. In this embodiment, when the display brightness is higher than the preset brightness and the temperature of the red-green LCD screen 6 is lower than the second preset temperature, it indicates that the original luminous brightness of the first group of projection light sources 1 is sufficient, and after passing through the projection system, the temperature of the red-green LCD screen 6 can be kept below the set value, reducing the loss of the red-green LCD screen. At this time, the original luminous brightness of the first group of projection light sources 1 is maintained, and the brightness of the first group of projection light sources 1 can be adjusted at any time according to needs.

[0068] It should be noted that, in one embodiment, the second preset temperature is lower than the first preset temperature.

[0069] In one embodiment, the projection controller is also used to monitor the color saturation of the aligned projection image in real time; the color saturation can be obtained by capturing and analyzing the projection image through an external camera connected to the projector; when the color saturation does not meet the requirements, manual fine-tuning can be received to adjust the luminous brightness or other parameters of the blue and green LEDs; or the projection controller can intelligently fine-tune the luminous brightness or other parameters of the blue and green LEDs according to the color saturation and the surrounding environmental parameters, including the ambient brightness.

[0070] Example 2 - A Two-Piece LCD Projection System

[0071] In one embodiment, a two-panel LCD projection system is also provided. The two-panel LCD projection system includes a two-panel LCD projection device as described in any of the preceding claims and a signal input device. The signal input device is electrically connected to the red-green LCD screen 6 and the black-and-white LCD screen 12 of the two-panel LCD projection device, respectively, wherein:

[0072] The signal input device is used to synchronously transmit red, green, and blue image signals to the red-green LCD screen 6 and the black-and-white LCD screen 12; this signal input device is also used to input the image to be projected.

[0073] The red-green LCD screen 6 parses and displays the red-green image signal from the received red-green-blue image signal;

[0074] The monochrome LCD screen 12 is used to parse and display the blue-green image signal from the received red-green-blue image signal.

[0075] In this embodiment, a two-panel LCD projection system is provided, which directly receives red, green, and blue images from the signal input device through the red-green LCD screen 6. These red, green, and blue images are the images to be projected. The red-green LCD screen 6 displays the color images by distinguishing and displaying the signals internally. Specifically, the red-green LCD screen 6 is used to display red and green images without processing the color signals before inputting them into their respective LCD screens. This reduces signal processing time (or reduces signal processing devices such as drivers, significantly improving display efficiency and cost).

[0076] The above are merely preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A two-panel LCD projection device, characterized in that, Comprising: a first light path imaging system and a second light path imaging system; the first light path imaging system is used for converting yellow light emitted by a first group of projection light sources (1) into red and green light through a red and green LCD screen (6), and then imaging the red and green light onto a screen through a projection lens (14); the second light path imaging system comprises a second group of projection light sources (8), a non-spherical lens (9), a reflector (10), a rear Fresnel lens (11), a second front Fresnel lens (7.2), a second polaroid (4.2), a black and white LCD screen (12), a dichroic mirror (13), and the projection lens (14); in the second light path imaging system, the second group of projection light sources (8) emit alternatingly flashing blue light and green light, which is collected by the non-spherical lens (9), reflected by the reflector (10) to the rear Fresnel lens (11), and then converted into second polarized light by the second polaroid (4.2) and incident on the black and white LCD screen (12), which receives the alternatingly flashing blue light and green light and alternately displays blue and green images, wherein the blue and green image display frequency is consistent with the flashing frequency of the second group of projection light sources (8), and then irradiates onto the dichroic mirror (13) after passing through the second front Fresnel lens (7.2), the dichroic mirror (13) reflects the alternating blue light reflection and green light with a wavelength higher than a preset value that passes through the second front Fresnel lens (7.2), and the rest of the light transmits, the reflected light transmits through the projection lens (14) and is imaged onto the screen, and is aligned with the imaging of the first light path imaging system.

2. The two-panel LCD projection device of claim 1, wherein, The red and green LCD screen (6) is used for receiving red, green and blue three-color images, and for displaying red and green images therein.

3. The two-panel LCD projection device of claim 1, wherein, The first group of projection light sources (1) are blue LED light sources coated with yellow fluorescent powder, and the second group of projection light sources (8) are blue-green mixed LED light sources.

4. The two-panel LCD projection device of claim 1, wherein, The first light path imaging system further comprises a light funnel (2), a rear Fresnel lens (3), a first polaroid (4.1), a blue light filter (5), a first front Fresnel lens (7.1), a dichroic mirror (13), and a projection lens (14); in the first light path imaging system, the yellow light emitted by the first group of projection light sources (1) is irradiated onto the rear Fresnel lens (3) after passing through the light funnel (2), and then becomes first polarized light after passing through the first polaroid (4.1), the first polarized light filters the blue light part in the first polarized light through the blue light filter (5) to form target yellow light, the target yellow light is condensed by the red and green LCD screen (6) and the first front Fresnel lens (7.1) to form red and green light, and the red and green light is imaged onto the screen by the projection lens (14) after passing through the dichroic mirror (13).

5. The two-panel LCD projection device of claim 4, wherein, In the first light path imaging system, the yellow light emitted by the first group of projection light sources (1) is irradiated onto the rear Fresnel lens (3) after passing through the light funnel (2) to form parallel first light beams.

6. The two-panel LCD projection device of claim 5, wherein, In the second light path imaging system, the second group of projection light source (8) emits the alternate cyan light which is gathered by the aspheric lens (9) and then is irradiated to the back Fresnel lens (11) by the mirror (10) to become the second light beam which is perpendicular to the first light beam.

7. The two-panel LCD projection device of claim 4, wherein, The first polarized light is P polarized light and the second polarized light is S polarized light.

8. The two-panel LCD projection device of claim 7, wherein, The red and green light passes through the dichroic mirror (13) and the light with wavelength greater than or equal to 480 nm is transmitted and the light with wavelength less than 480 nm is reflected; when the dichroic mirror (13) reflects the alternate cyan light which passes through the second front Fresnel lens (7.2), the light with wavelength less than 480 nm is reflected, the light with wavelength of 540-560 nm is reflected and the light with other wavelengths is transmitted.

9. The two-panel LCD projection device of claim 1, wherein, The angle between the red and green LCD screen (6) and the black and white LCD screen (12) is 90°.

10. A two-panel LCD projection system, characterized by comprising: The two-piece LCD projection system comprises the two-piece LCD projection device and the signal input device according to any one of claims 1-9, and the signal input device is electrically connected with the red and green LCD screen (6) and the black and white LCD screen (12) of the two-piece LCD projection device, wherein: The signal input device is used for synchronously transmitting the red, green and blue image signals to the red and green LCD screen (6) and the black and white LCD screen (12); The red and green LCD screen (6) analyzes and displays the red and green image signals from the received red, green and blue image signals; The black and white LCD screen (12) is used for analyzing and displaying the cyan image signals from the received red, green and blue image signals.

Images