Display device

Abstract

The present application protects a single-board liquid crystal projection device, which comprises a white light source module for emitting a first light beam comprising at least red, green and blue light components; a first wavelength angle spectrometer, the first light beam passing through the first wavelength angle spectrometer to become a color light beam; a first microlens array for converging the color light beam so that the color light beam forms red-green-blue separated color stripes or color spots on a reference plane; a liquid crystal display device comprising a liquid crystal pixel array comprising a plurality of liquid crystal pixels, the liquid crystal pixel array being arranged on the reference plane, different color stripes or color spots falling on different liquid crystal pixels respectively, the liquid crystal display device being used for modulating incident light to form a color image for emission; a projection lens for projecting the color image emitted by the liquid crystal display device to a predetermined position; wherein when the cross-sectional area of the first light beam is comparable to the effective pixel area of the liquid crystal display device, the first light beam is small divergence angle light.

Description

Technical Field

[0001] This invention relates to the field of display technology, and in particular to a display device. Background Technology

[0002] With the development of society and the economy, and the continuous advancement of information technology, people's demand for large-screen entertainment is growing stronger. Taking the living room as an example, recent market sales show that LCD TV sizes are gradually increasing. However, the advent of the information age has led to fragmented time, and the living room is no longer the only place for video entertainment. Moreover, due to the large size and weight of LCD TVs, they cannot be used anytime, anywhere. On the other hand, although mobile phone screens have made great strides in size, and even larger smart tablets designed specifically for entertainment have emerged, their display methods limit the ability to achieve truly large-screen displays. Therefore, to achieve flexible large-screen displays, projection technology is currently the only viable option.

[0003] A projection display system mainly consists of an illumination system, an optomechanical system, and a projection lens. The spatial light modulator, also known as a "light valve," is a crucial component in the optomechanical system. A light valve is typically a pixelated planar device, where each pixel can independently control the incident illumination light through transmission or reflection, thereby controlling the luminous flux of each pixel to form the displayed image. Based on the type of spatial light modulator, projection display systems can be broadly classified into reflective DMD (Digital Micro-Mirror Device) projection, transmissive LCD (Liquid Crystal Display) projection, and reflective LCoS (Liquid Crystal on Silicon) projection. Based on the number of spatial light modulators, they can be further classified into single-panel projection, dual-panel projection, and triple-panel projection.

[0004] Three-panel projectors require three spatial light modulators to modulate the RGB three-color images respectively. These images are then combined using a light-combining element to create a color image, which is then projected through a projection lens. On one hand, the light-combining element is typically a solid prism, resulting in large size and mass. On the other hand, the light-combining element occupies the projection optical path space between the spatial light modulator and the projection screen. Furthermore, the complex optical path, high cost, and high alignment accuracy requirements of three-panel projectors make them unsuitable for portable projection. Two-panel projectors have a similar optical path design to three-panel projectors, and for the same reasons, they are also unsuitable for portability.

[0005] Single-panel projection uses only a single light valve device and only processes light intensity, not color. When displaying an image, at time t1, red illumination light shines on the light valve, which transmits or reflects the red image; at time t2, green illumination light shines on the light valve, displaying a green image; and at time t3, blue illumination light shines on the light valve, displaying a blue image. When the switching speed between t1, t2, and t3 is fast enough, thanks to the persistence of vision in the human eye, the observer's eye will blend the three monochrome images into a single color image, thus achieving color display. However, this optical architecture has several drawbacks. First, if a white light source is used, only one of the red, green, or blue monochrome light sources can be used at any given time. This means that when displaying a red image, green and blue need to be filtered out, leading to low optical efficiency. Second, the three-color images need to switch at a sufficiently fast temporal speed, requiring a sufficiently fast refresh rate / response time for the light valve device. Otherwise, the observer may see color breakup patterns or rainbow-like patterns at the boundaries between two colors. Because the response time of a DMD is only 15μs, that of an LCoS is about 1.5ms, and that of an LCD is typically >7ms, single-DMD projection and single-LCoS projection are currently the main types of projection, and single-panel projection using an LCD as the light valve is generally not considered. However, due to the reflective nature of their optical paths, single-DMD projection and single-LCoS projection still have complex optical paths, making it difficult to further reduce their size.

[0006] To overcome the problem of low light utilization in single-panel projection using white light sources and to solve the color separation issue, US Patent 7046407B2 proposes a single-panel transmissive LCD projection scheme. Please see [link to patent]. Figure 1The light emitted by the white bulb light source 14 is converted into parallel white light by the reflector cup 12. The grating 16 converts this parallel white light into colored beams of different colors propagating at different angles (i.e., the principal axis angles of the red, green, and blue light beams are different). These colored beams are converged by the single microlens array 18 and straightened by the grating 22, becoming spatially separated colored beams (i.e., the red, green, and blue beams do not overlap spatially), which are then incident on the LCD 20. Subsequently, the LCD 20 modulates the incident colored beams, forming a colored image light with separated red, green, and blue pixels every 1 / 3 frame. Under the action of the swing plate 24, every three 1 / 3 frames of colored image light are spatially misaligned and time-superimposed, thus forming a frame of colored image with overlapping red, green, and blue pixels. This image is then projected onto the screen 28 by the projection lens 26 to form a large-screen display. Although this technical solution seems to theoretically provide the possibility of single-panel LCD projection, no related actual products have appeared in the past twenty years, and the patents for this type of technical solution have expired early due to discontinuation, indicating that this technical route has serious practical feasibility issues. Researchers involved in this invention have discovered that this technical solution often suffers from pixel crosstalk and image display chaos in applications. Moreover, the efficiency of the entire optical system is very low. To achieve usable display brightness, a very high light source power is required. However, the high-power light source brings with it a larger optical system, a larger heat dissipation system, higher cost, and more severe pixel crosstalk. Summary of the Invention

[0007] To address the shortcomings of existing single-panel LCD projection devices, such as pixel crosstalk and poor practicality, this invention provides a single-panel LCD projection device with good display effect and high system efficiency. The device includes a white light source module for emitting a first light beam, the first light beam comprising at least red, green, and blue light components; a first wavelength angle beam splitter for emitting light of different wavelengths at different angles, the first light beam being converted into a colored light beam by the first wavelength angle beam splitter; and a first microlens array, composed of multiple microlens units, disposed in the light path of the emitted light from the wavelength angle beam splitter, for converging the colored light beam, thereby achieving a high display effect and high system efficiency. A colored light beam forms red, green, and blue separated colored stripes or spots on a reference plane; a liquid crystal display device includes a liquid crystal pixel array containing multiple liquid crystal pixels, the liquid crystal pixel array being disposed on the reference plane, with different colored stripes or spots falling onto different liquid crystal pixels respectively; the liquid crystal display device is used to modulate the incident light to form a colored image output; a projection lens is used to project the colored image output by the liquid crystal display device onto a predetermined position; wherein, when the cross-sectional area of ​​the first light beam is equivalent to the effective pixel area of ​​the liquid crystal display device, the divergence half-angle of the first light beam is not greater than 6°.

[0008] In one embodiment, when the cross-sectional area of ​​the first beam is comparable to the effective pixel area of ​​the liquid crystal display device, the divergence half-angle of the first beam is no greater than 3°.

[0009] In one embodiment, when the cross-sectional area of ​​the first beam is comparable to the effective pixel area of ​​the liquid crystal display device, the divergence half-angle of the first beam is not greater than 1.67°.

[0010] In one embodiment, when the cross-sectional area of ​​the first beam is comparable to the effective pixel area of ​​the liquid crystal display device, the divergence half-angle of the first beam is not less than 0.014°.

[0011] In one embodiment, the present invention provides a single-panel liquid crystal projection device, comprising a white light source module for emitting a first light beam, the first light beam including at least red, green and blue light components; a first wavelength angle beam splitter for emitting light of different wavelengths at different angles, the first light beam becoming a colored light beam after passing through the first wavelength angle beam splitter; a first microlens array, composed of multiple microlens units, disposed in the output light path of the wavelength angle beam splitter, for converging the colored light beam, so that the colored light beam forms red-green-blue separated colored stripes or colored spots on a reference plane; a liquid crystal display device, including a liquid crystal pixel array containing multiple liquid crystal pixels, the liquid crystal pixel array being disposed on the reference plane, the colored stripes or colored spots of different colors falling onto different liquid crystal pixels, the liquid crystal display device for modulating the incident light to form a colored image output; and a projection lens for projecting the colored image output by the liquid crystal display device onto a predetermined position; wherein, when the cross-sectional area of ​​the first light beam is equivalent to the effective pixel area of ​​the liquid crystal display device, the divergence half angle θ of the first light beam satisfies the following relationship:

[0012]

[0013] Where n is the refractive index of the microlens unit, x is the size of the liquid crystal pixel, and L is the distance between the first microlens array and the liquid crystal pixel array.

[0014] Compared with the prior art, the present invention has the following beneficial effects: The first beam containing red, green and blue light components emitted from the white light source module is split by the first wavelength angle beam splitter, causing the main optical axes of the red, green and blue beams to propagate at different angles. After passing through the first microlens array, the red, green and blue beams passing through the same microlens converge towards different spatial positions, thus incident on different liquid crystal pixels. By limiting the size of the divergence half-angle of the first beam to meet the condition of a small divergence half-angle, when the first beam passes through the optical devices between the white light source module and the liquid crystal display device and converts part of the surface distribution into an angular distribution, the surface distribution of light on the liquid crystal display device can satisfy the separation of the red, green and blue distributions. This prevents different colored light spots from interfering with adjacent pixels, forming a color image with reduced pixel crosstalk on the liquid crystal display device and improving display quality. At the same time, by reducing the divergence half-angle of the first beam, the energy transfer efficiency of each optical device and the light collection efficiency of the projection lens are improved, increasing the light utilization rate of the overall system and making the single-panel liquid crystal projection solution truly practical.

[0015] In one embodiment, the white light source module includes at least an LED light source and an angle distribution converter, wherein the light emitted by the LED light source is converted by the angle distribution converter to obtain a first beam; or, the white light source module includes at least a laser fluorescent light source and an angle distribution converter, wherein the light emitted by the laser fluorescent light source is converted by the angle distribution converter to obtain a first beam; or, the white light source module includes a semiconductor solid-state light source array and a light shaping device, wherein the light emitted by the semiconductor solid-state light source array is shaped by the light shaping device to obtain a first beam.

[0016] In one embodiment, the white light source module further includes a polarization converter for emitting the first beam in a single polarization state.

[0017] In one embodiment, the white light source module includes at least a white light emitting unit, a conical reflector, and a reflective polarization selection device arranged sequentially along the optical path. The smaller end of the conical reflector is the incident surface, and the larger end is the exit surface. Unpolarized white light emitted from the white light emitting unit is incident through the incident surface of the conical reflector. The light incident into the conical reflector is reflected by the sidewall of the conical reflector and then exits through the exit surface or directly. At least part of the light exiting the conical reflector is transmitted through the reflective polarization selection device and exits with a single polarization state, while part is reflected by the reflective polarization selection device and returns to the conical reflector.

[0018] In one embodiment, a second wavelength angle beam splitter is further included. The second wavelength angle beam splitter is disposed between the first microlens array and the liquid crystal display device, and is used to make the color beams into a color beam array with red, green and blue separated and the principal optical axes of each beam parallel; or, the second wavelength angle beam splitter is disposed between the liquid crystal display device and the projection lens, and is used to make the principal optical axes of each color beam of the color image parallel.

[0019] In one embodiment, the second wavelength angle beam splitter is a diffractive optical device, a second microlens array, or a dispersive element.

[0020] In one embodiment, the second wavelength angle beam splitter is a second microlens array, and every three microlens units of the second microlens array correspond to one microlens unit of the first microlens array.

[0021] In one embodiment, a pixel offset device is further included, disposed in the outgoing light path of the liquid crystal display device, for translating the light beam of the color image along a direction perpendicular to the optical axis, so that color images at different translation positions are superimposed in sequence.

[0022] In one embodiment, a filter unit disposed in the optical path is further included, the filter unit being used to reduce the light component between the dominant wavelength of green light and the dominant wavelength of red light in the optical path and / or the filter unit being used to reduce the light component between the dominant wavelength of blue light and the dominant wavelength of green light in the optical path.

[0023] In one embodiment, an absorption grid is further included, disposed between the first microlens array and the liquid crystal display device. The absorption grid includes an array of absorption areas and light-transmitting areas. The absorption areas are disposed between the green dominant wavelength beam and the red dominant wavelength beam of the color beam and / or the absorption areas are disposed between the blue dominant wavelength beam and the red dominant wavelength beam of the color beam.

[0024] In one embodiment, the absorption grid is disposed on the liquid crystal display device and also serves as a circuit wire of the liquid crystal display device.

[0025] In one embodiment, the liquid crystal display device includes a polarizer, which is disposed separately from the liquid crystal pixel array.

[0026] In one embodiment, the first microlens array is a one-dimensional cylindrical lens array, with each cylindrical lens corresponding to three rows or three columns of liquid crystal pixels; or the first microlens array is a two-dimensional cylindrical lens array, with each cylindrical lens corresponding to three liquid crystal pixels.

[0027] In one embodiment, the liquid crystal pixel array includes a plurality of color liquid crystal pixels, each of the color liquid crystal pixels including at least three liquid crystal pixels, and the liquid crystal display device further includes a light mixing device located on its emission side, the light mixing device being used to mix the emitted light of each of the color liquid crystal pixels uniformly.

[0028] In one embodiment, a pixel offset device is further included, disposed in the outgoing light path of the liquid crystal display device, for translating the light beam of the color image along a direction perpendicular to the optical axis, so that color images at different translation positions are superimposed in sequence.

[0029] In one embodiment, the first wavelength angle beam splitter includes at least three partitions and a driving device. Under the drive of the driving device, each partition is located in the optical path of the first beam at different times, so that the first wavelength angle beam splitter emits colored beams with different red, green and blue arrangements at different times. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the optical path of a single-panel transmissive LCD projection scheme in the prior art.

[0031] Figure 2 This is a schematic diagram of the basic optical architecture of the single-panel liquid crystal projection device of the present invention.

[0032] Figure 3 This is a schematic diagram of the structure of a first embodiment of the single-panel liquid crystal projection device of the present invention;

[0033] Figure 4 This is a functional diagram of a wavelength angle beam splitter;

[0034] Figure 5 This is a schematic diagram of the optical path from the microlens to the liquid crystal pixel;

[0035] Figure 6 This is a schematic diagram of the optical path from another microlens to the liquid crystal pixel;

[0036] Figure 7 This is a schematic diagram of a modified embodiment of Embodiment 1 of the present invention;

[0037] Figure 8 This is a schematic diagram of another modified embodiment of Embodiment 1 of the present invention;

[0038] Figure 9 This is a schematic diagram of another modified embodiment of Embodiment 1 of the present invention;

[0039] Figure 10 This is a schematic diagram of the structure of a second embodiment of the single-panel liquid crystal projection device of the present invention;

[0040] Figure 11This is a schematic diagram of the optical path structure from the first microlens array to the second wavelength angle beam splitter in the single-panel liquid crystal projection device of the present invention.

[0041] Figure 12 This is a schematic diagram of the structure of a third embodiment of the single-panel liquid crystal projection device of the present invention;

[0042] Figure 13 This is the spectral curve of the filter unit of the single-panel liquid crystal projection device of the present invention after filtering;

[0043] Figure 14 This is a schematic diagram of the partial optical path structure from the first microlens array to the liquid crystal pixel array in Embodiment 5 of the single-panel liquid crystal projection device of the present invention.

[0044] Figure 15 This is a partial optical path structure diagram of Embodiment 7 of the single-panel liquid crystal projection device of the present invention.

[0045] Figure 16 This is a schematic diagram of the time-series overlay of images after pixel offset. Detailed Implementation

[0046] This invention addresses the practicality issues of single-panel liquid crystal projection technology. The key problem lies in the light source module – traditional light sources have large emitting surfaces and wide emission angles, resulting in very large optical extension. This makes true color spot separation impossible when the light source is matched with a microlens array and liquid crystal display device. This invention combines a white light source with a small optical extension with a "white light color separation followed by single-panel liquid crystal display" technology, making the theoretical solution truly practical and revitalizing the old technology with new technology.

[0047] Please see Figure 2This is a schematic diagram of the basic optical architecture of the single-panel liquid crystal projection device of the present invention. The single-panel liquid crystal projection device includes a white light source module 10, a first wavelength angle beam splitter 20, a first microlens array 30, a liquid crystal display device 40, and a projection lens 50. The white light source module 10 emits a first light beam, which includes at least red, green, and blue light components. The first light beam is incident on the first wavelength angle beam splitter 20 and is split into colored beams of different wavelengths propagating at different angles, i.e., red, green, and blue light propagate at different angles, and there is an angle between their principal optical axes. The colored beam is incident on the first microlens array 30, which is composed of multiple microlens units used to converge the colored beam. Each microlens unit converges the red, green, and blue light beams incident on it, so that the colored beams form red, green, and blue separated colored stripes or colored spots on a reference plane. The liquid crystal display device 40 is disposed on the reference plane and includes a liquid crystal pixel array containing multiple liquid crystal pixels, so that color stripes or color spots of different colors fall onto different liquid crystal pixels respectively. Under the control of the driving signal, the liquid crystal display device 40 modulates the incident light to form a color image emission. Then, the projection lens 50 projects the color image emitted by the liquid crystal display device 40 onto a predetermined position to form a display image.

[0048] In this optical architecture, traditional light bulbs produce so-called parallel white light through the wick and reflector, utilizing the optical principle of placing the wick at the focal point of the parabolic reflector. However, this optical model is built under ideal conditions, treating the wick as a point source. In reality, the emitting part of the wick is filamentary and its size is far from being that of a point source. Even with optimized design of the reflector's surface, due to the conservation of optical spread, the divergence angle of the light emitted from a wick with a 4π solid angle is still very large when converted to approximately parallel light. Only the light emitted from the point considered the optical center of the wick has good parallelism. In particular, the higher the power of the light bulb, the larger the size of the wick, and the greater its optical spread, resulting in a larger divergence angle for the same beam area. Furthermore, when the white light passes through the wavelength angle beam splitter, although the principal optical axes of different wavelengths are offset from each other, the light with large divergence angles will overlap. For example, the large divergence angle of the green light near the red light side will overlap with the large divergence angle of the red light near the green light side, causing the light at that spatial angle to mix into yellow light, which cannot display the image correctly.

[0049] With the same optical architecture, this invention does not primarily pursue factors such as brightness, but focuses on the parameter of "optical spread," which is independent of brightness and power. By using a light source with a small optical spread, the first beam emitted by the white light source module 10, after passing through the first wavelength angle beam splitter 20, results in a colored beam with less overlap between beams of different wavelengths. Then, through the first microlens array 30, the beam is further spatially separated, resulting in more clearly separated colored stripes or colored spots on the reference plane. These colored stripes or colored spots can then form a correctly displayed image through the liquid crystal display device 40.

[0050] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings and descriptions.

[0051] Please see Figure 3 This is a schematic diagram of the structure of a single-panel liquid crystal projection device according to a first embodiment of the present invention. The single-panel liquid crystal projection device 100 includes a white light source module 110, a first wavelength angle beam splitter 120, a first microlens array 130, a liquid crystal display device 140, and a projection lens 150.

[0052] The white light source module 110 is used to emit a first light beam, which includes at least red, green and blue light components. In this embodiment, the white light source module 110 includes a white light emitting unit 111, a conical reflector 112, a reflective polarization selection device 113 and a collimating lens 114 arranged sequentially along the optical path direction.

[0053] The smaller end of the conical reflector 112 is the incident surface, and the larger end is the exit surface. This allows the unpolarized white light emitted by the white light emitting unit 111 to enter the conical reflector through the incident surface, be reflected by the sidewalls of the conical reflector, and then exit through the exit surface or directly. This results in the exit spot area being larger than the incident spot area, thereby reducing the beam divergence angle. In this embodiment, the conical reflector 112 is a solid conical light guide rod, and the beam is reflected by total internal reflection from the side of the conical reflector 112. In other embodiments of the present invention, the conical reflector 112 can also be a hollow conical reflector composed of a reflective plate / reflective surface, which will not be described further here.

[0054] In this embodiment, the emitted light from the conical reflector 112 is unpolarized white light. It is incident along the optical path onto the reflective polarization selector 113. Part of the light passes through the reflective polarization selector 113 and continues to exit with a single polarization state. The remaining light is reflected by the reflective polarization selector 113 and returns to the conical reflector 112. After repeated reflections within the conical reflector 112, it exits again through the exit surface of the conical reflector 112 and reaches the reflective polarization selector 113, thereby improving the utilization rate of the first beam. To reduce the number of times the recovered first beam is retrieved, a structure such as a quarter-wave plate can be provided within the conical reflector to change the polarization state of the beam. In this invention, the reflective polarization selector 113 can be, for example, a wire grid polarizer.

[0055] In this embodiment, the white light source module 110 adds a collimating lens 114 after the reflective polarization selection device 113 to further collimate the first beam, allowing it to smoothly enter the downstream optical element in the optical path. It is understood that in other embodiments of the present invention, a collimating lens may not be provided, for example, when the first beam from the upstream optical path satisfies a small divergence angle.

[0056] See also Figure 3 The first light beam from the white light source module 110 is incident on the first wavelength angle beam splitter 120 and is split into colored beams of different wavelengths propagating at different angles. See also... Figure 4 This is a functional schematic diagram of the wavelength angle beam splitter of the present invention. As shown in the figure, a white light beam (large arrow W in the figure) is incident on the wavelength angle beam splitter from the left. Specifically, this white light beam is a quasi-parallel beam with a divergence half-angle of β (shown in the dashed circle in the figure), and its principal optical axis is perpendicular to the wavelength angle beam splitter. Due to the action of the wavelength angle beam splitter, light of different wavelengths propagates along different paths within the beam splitter and exits at different angles. This causes the white light beam to split into colored beams on the exit side of the wavelength angle beam splitter, as shown in the figure, at least splitting into red, green, and blue beams with different exit angles (corresponding to the beams with large arrows R / G / B in the figure). Beams of the same color remain quasi-parallel beams, that is, they propagate along the same principal optical axis and have a certain divergence half-angle. As shown in the dashed circle on the right side of the figure, red, green, and blue (i.e., RGB) are represented by dotted lines, solid lines, and dashed lines, respectively. The beam arrows in the middle of each represent the principal optical axis, and the arrows on both sides represent the rays with the maximum divergence angle at the edge of the beam. Because in some embodiments of the present invention, white light is a continuous spectrum, resulting in a continuous change in the angular distribution of the principal optical axis for each wavelength, it is inevitable that two types of light with different wavelengths exist in the same angular emission direction. However, the component of mixed colors between the principal wavelengths is relatively small. Therefore, the present invention mainly considers light near the principal wavelengths of the three primary colors red, green, and blue used for display. Figure 4In the aforementioned scheme, the white light beam is incident on the wavelength angle beam splitter in a manner perpendicular to the main optical axis. In other embodiments of the present invention, the first beam of white light may also enter the wavelength angle beam splitter in a manner of oblique incidence.

[0057] The above describes wavelength-angle beam splitters from an optical function perspective. Specifically, wavelength-angle beam splitters can be diffractive optical devices, such as diffraction gratings, binary optical elements, and other micro-optical structures that can achieve diffraction. Wavelength-angle beam splitters can also be dispersive elements, such as prisms or devices containing prism structures.

[0058] A colored beam from the wavelength angle beam splitter 120 is incident on the first microlens array 130 in the outgoing light path. The first microlens array 130 consists of multiple microlens units, each of which splits the incident colored beam into a sub-beam and converges them, so that the light of each color is focused into a region, thereby causing the colored beam to form red, green, and blue separated colored stripes or colored spots on the reference plane. In this invention, the reference plane is located at the focal plane of the first microlens array. Due to factors such as assembly errors, and considering the thickness of the liquid crystal layer, the reference plane can be set at a position ±10% of the distance from the focal plane to the first microlens array.

[0059] In this invention, the first microlens array can be a one-dimensional cylindrical lens array or a two-dimensional cylindrical lens array. When the first microlens array is a one-dimensional cylindrical lens array, the colored light beam is focused into colored stripes with separate red, green, and blue colors; when the first microlens array is a two-dimensional cylindrical lens array, the colored light beam is focused into colored spots with separate red, green, and blue colors.

[0060] The liquid crystal display device 140 includes a liquid crystal pixel array 141 containing multiple liquid crystal pixels and a polarizer 142. The liquid crystal pixel array 141 is disposed on a reference plane, so that color stripes or color spots of different colors fall onto different liquid crystal pixels respectively. When the first microlens array is a one-dimensional cylindrical lens array, each cylindrical lens corresponds to three rows or three columns of liquid crystal pixels; when the first microlens array is a two-dimensional cylindrical lens array, each cylindrical lens corresponds to three liquid crystal pixels.

[0061] The liquid crystal display device 140 is controlled by a circuit to modulate the polarization state of the incident light, resulting in light containing different polarization states. This light is then filtered out by a polarizer 142 to remove some of the polarization states, thus forming a color image. The polarizer 142 can be a polarizing filter. Typically, the polarizer is positioned close to the liquid crystal pixel array. In this embodiment, the polarizer 142 is separated from the liquid crystal pixel array 141, avoiding direct thermal contact and preventing the heat generated by the liquid crystal pixel array 141 from causing aging or damage to the polarizer 142. In other embodiments of the invention, the polarizer 142 can also be positioned close to the liquid crystal pixel array 141, such as... Figure 10 The liquid crystal display device 240 of Embodiment 2 is shown.

[0062] A projection lens 150 is disposed in the outgoing light path of the liquid crystal display device 140 and is used to project a color image to a predetermined position to form an image that can be viewed by a viewer. In this embodiment, the projection lens 150 is composed of multiple lenses. It is understood that the number of lenses included in the projection lens in the accompanying drawings does not limit the number of lenses included in the projection lens of the present invention. Those skilled in the art can design the product lens according to the needs of the projection scenario. The projection lens may also include optical structures such as reflective surfaces, which will not be described in detail here.

[0063] In the similar optical architecture of this invention, pixel crosstalk mainly occurs during the transition from the first microlens array 30 to the liquid crystal display device 40. The inventors have conducted a detailed study on this issue. Please refer to [link to relevant documentation]. Figure 5 This is a schematic diagram of the optical path from the microlens to the liquid crystal pixel. For ease of explanation, this diagram only shows one microlens unit 30-1 of the first microlens array 30 and its corresponding group of liquid crystal pixels 41-1. Each group of liquid crystal pixels 41-1 includes RGB three pixels, forming a complete color pixel. (If the microlens unit 30-1 is a unit in the first microlens array composed of a one-dimensional array of cylindrical lenses, then the corresponding group of liquid crystal pixels 41-1 is a row / column of elongated pixels.)

[0064] Figure 5 The angle of view selection affects the angle of beam convergence. Taking green light G as an example, the solid line represents the light ray of green light G along the principal optical axis, and the dashed line represents the light ray of green light G along the direction of the maximum emission half angle θ (for ease of explanation, only the light from one side is described). In this embodiment, the principal optical axis of green light G is perpendicular to the liquid crystal display device.

[0065] To avoid pixel crosstalk, it is necessary to prevent the outermost green light with the largest divergence half-angle from illuminating blue or red pixels. The study examines the optical path from the incident surface of the first microlens array to the incident surface of the liquid crystal pixel array. For illustration purposes, a surface A close to the incident surface of the first microlens array is designated as a reference wavefront. This reference wavefront A is infinitely close to the incident surface of the first microlens array (the distance in the figure is exaggerated for ease of marking). Therefore, it can be assumed that the cross-sectional area of ​​the first beam passing through the reference wavefront A is equal to the cross-sectional area of ​​the first microlens array, and the divergence half-angle θ of the first beam passing through the reference wavefront A is equal to the incident light divergence half-angle of the first microlens array. To ensure that the optical paths of each microlens unit are essentially identical, the size of the entire first microlens array is comparable to the size of the liquid crystal pixel array. Therefore, the divergence half-angle θ is also the divergence half-angle of the first beam when the cross-sectional area of ​​the first beam is comparable to the effective pixel area of ​​the liquid crystal display device.

[0066] As shown in the figure, the size of the monochrome liquid crystal pixel is x, the distance between the first microlens array and the liquid crystal pixel array is L, and the refractive index of the microlens unit 30-1 is n. Then, the divergence half-angle θ of the first beam satisfies the following relationship:

[0067]

[0068] In this invention, the distance L between the first microlens array and the liquid crystal pixel array is influenced by multiple factors. Firstly, the distance L is directly related to the focal length of the microlens units in the first microlens array; an excessively small focal length leads to an increase in the radius of curvature of the microlens units, increased cost, and increased spherical aberration. Secondly, due to the influence of the assembly precision of optical components, the smaller L is, the greater the impact of assembly errors. Furthermore, there is the thermal distortion effect caused by the heat transfer from the heated liquid crystal pixel array to the first microlens array; the smaller L is, the more pronounced the heat transfer. The size x of the liquid crystal pixel is affected by its own cost and the cost of the projection lens in the downstream optical path, and cannot be too large. Therefore, considering multiple factors, when the cross-sectional area of ​​the first beam is comparable to the effective pixel area of ​​the liquid crystal display device, the divergence half-angle θ of the first beam in this invention is no greater than 6°.

[0069] Please see Figure 6 This is a schematic diagram of the optical path from another microlens to the liquid crystal pixel. This diagram only uses the red light R as the analysis ray; the path of the green light and the markings in the diagram can be found in the reference diagram. Figure 5Due to the wavelength angle beam splitter in the upstream optical path, there is an angle between the principal optical axes of red light R and green light G. Red light R is incident on the first microlens array at an overall oblique angle and, under the converging effect of the microlens units, converges onto the red pixel region of the red-green-blue pixel group. Similarly, the solid line represents the ray of red light R along the principal optical axis, and the dashed line represents the ray of red light R along the direction of the maximum emission half-angle (for ease of explanation, only one side of the light is described). Considering only the extreme case where red light completely covers the red pixels, to prevent pixel crosstalk, then... Figure 6 The red light situation shown is the same as Figure 5 The situation is similar for the green light, therefore, the red light divergence half-angle θ of the first beam also satisfies either not greater than 6° or satisfies the following condition:

[0070]

[0071] It is worth noting that before the first beam is split into colored beams by the first wavelength angle beam splitter, the red, green, and blue light components are in an overlapping state, and their respective beam cross-sectional areas and beam divergence angles are the same. After the first beam becomes a colored beam, the propagation angles of each beam along the principal axis change, but the beam cross-sectional areas can still be considered the same. Therefore, according to the conservation of optical spread, the divergence angles of the red, green, and blue light are also the same. Thus, the divergence angle of the red-green-blue monochromatic beam can be equated to the divergence angle of the white light in the first beam before angle beam splitting.

[0072] Please continue reading Figure 6From the perspective of the color liquid crystal pixel group 41-1 containing red, green, and blue liquid crystal pixels, the light emitted from this color pixel with the largest angle comes from the maximum divergence half-angle red light incident from the outermost edge of a microlens unit. This red light, converged by the microlens unit 30-1, reaches the outermost edge of the red liquid crystal pixel (i.e., the outermost edge of the entire red, green, and blue color pixel group). This light is then modulated by the red liquid crystal pixel and emitted, becoming the emitted light of the liquid crystal display device 140 with the maximum emission half-angle. To improve light utilization, the projection lens 150 collects as much of the emitted light as possible from the liquid crystal display device 140; therefore, the entrance half-angle of the projection lens 150 must not be less than the maximum emission half-angle of the liquid crystal display device 140. Generally, the larger the collection angle of the lens, the higher the design difficulty and cost. In the optical architecture of this invention, the required collection angle of the lens is related to the liquid crystal pixel size x, the distance L between the first microlens array and the liquid crystal pixel array, and the refractive index n of the microlens unit. x, L, and n are also related to the divergence half-angle θ of the first beam. Based on a study of the practical commercialization feasibility of the lens, this invention preferably specifies that when the cross-sectional area of ​​the first beam is comparable to the effective pixel area of ​​the liquid crystal display device, the divergence half-angle of the first beam is no greater than 3°. More preferably, when the cross-sectional area of ​​the first beam is comparable to the effective pixel area of ​​the liquid crystal display device, the divergence half-angle of the first beam is no greater than 1.67°, exhibiting superior economic efficiency.

[0073] Understandable, Figure 5 and Figure 6 In the example, the blue light and blue liquid crystal pixels are symmetrically positioned with the red light and red liquid crystal pixels. Therefore, this invention will only use red light as an example for illustration. The case of blue light is basically the same as that of red light and will not be described again.

[0074] The above, combined with Figures 3-6 The first embodiment and the general technical features of the present invention are described. In the first embodiment, the white light source module 110 includes a white light emitting unit 111, a conical reflector 112, a reflective polarization selection device 113, and a collimating lens 114 arranged sequentially along the optical path direction. The white light emitting unit 111 can be an LED light source or a laser fluorescent light source (i.e., white light is obtained by laser excitation of fluorescent materials). More generally, in the present invention, the white light source module can include at least an LED light source and an angle distribution converter, wherein the light emitted by the LED light source is converted by the angle distribution converter to obtain a first beam.

[0075] An angle distribution converter utilizes the principle of optical spread conservation to make the cross-sectional area of ​​the outgoing beam larger than that of the incident beam, thereby reducing the beam divergence angle. LED light sources themselves have a large divergence angle, making it impossible to directly emit a usable first beam; therefore, an angle distribution converter is needed to obtain the first beam. The conical reflector 112 and collimating lens 114 in Embodiment 1 can be considered as an angle distribution converter.

[0076] In other embodiments of the present invention, the white light source module may further include at least a laser fluorescent source and an angle distribution converter. The light emitted from the laser fluorescent source is converted by the angle distribution converter to obtain a first light beam. Please refer to [link to relevant documentation]. Figure 7 This is a schematic diagram of a modified embodiment of Embodiment 1 of the present invention. The single-panel liquid crystal projection device 100' includes a white light source module 110', a first wavelength angle beam splitter 120, a first microlens array 130, a liquid crystal display device 140, and a projection lens 150. Figure 7 In the modified embodiment shown, the numbering and Figure 3 The same parts are described in Embodiment 1. The difference between this embodiment and Embodiment 1 is that in this embodiment, the white light source module 110' includes a laser fluorescent source and an angle distribution converter. The laser fluorescent source includes an excitation source 115 and a wavelength conversion device 116; the angle distribution converter includes a conical reflector 112' with an inlet port. The excitation light emitted from the excitation source 115 enters the conical reflector 112' through the inlet port and then reaches the wavelength conversion device 116. In one specific embodiment, the excitation source 115 is a blue laser (such as a blue laser diode or a blue laser diode array), and the wavelength conversion device 116 includes a yellow fluorescent material. The blue laser excites the yellow fluorescent material to generate yellow light and unabsorbed blue light, thereby forming white light output. This white light has a large divergence angle, thus a large beam cross-section and a small divergence angle are obtained through the action of the conical reflector 112'. The wavelength conversion device 116 may include a fluorescent glass layer, a fluorescent ceramic layer, or an organic fluorescent layer. Compared to the technical solution of Embodiment 1, this modified embodiment replaces the light source, resulting in higher luminous efficiency and suitability for applications with higher brightness.

[0077] Figure 7 In the modified embodiment described above, the wavelength conversion device 116 is a reflective wavelength conversion device, that is, the incident side of the excitation light and the emitting side of the fluorescence are on the same side of the wavelength conversion device 116. In other embodiments of the present invention, the wavelength conversion device may also be a transmissive wavelength conversion device, and the excitation light source is disposed on the side of the wavelength conversion device away from the angular distribution converter.

[0078] In other embodiments of the present invention, the white light source module may further include a semiconductor solid-state light source array and a light shaping device. The light emitted from the semiconductor solid-state light source array is shaped by the light shaping device to obtain a first light beam. Please refer to [link to relevant documentation]. Figure 8 This is a schematic diagram of another modified embodiment of Embodiment 1 of the present invention. The single-panel liquid crystal projection device 100” includes a white light source module 110”, a first wavelength angle beam splitter 120, a first microlens array 130, a liquid crystal display device 140 and a projection lens 150. Figure 8 In the modified embodiment shown, the numbering and Figure 3 For the same parts, refer to the description in Example 1.

[0079] In this modified embodiment, the white light source module 110" includes a solid-state light source array 117, a light shaping device 118, and a polarization converter 113'. Specifically, the solid-state light source array 117 includes a red laser diode array, a green laser diode array, and a blue laser diode array, which are combined and homogenized by the light shaping device 118. The light shaping device 118 can be, for example, an integrating bar. The emitted light from the light shaping device 118 is processed by the polarization converter 113' to obtain a first beam emitted with a single polarization state. The polarization converter 113' can be a PCS array, which can be applied in various embodiments to replace the reflective polarization selection device 113, but this will cause a dilution of optical spread.

[0080] exist Figure 8 In the modified embodiment shown, the solid-state light source array can also be replaced with an LED light source array. Since its divergence angle is large, an angle distribution converter is still needed to convert it into light with a small divergence angle to facilitate the subsequent optical path.

[0081] exist Figure 8 In this embodiment, the RGB three-color solid-state light source is directly coupled through an integrating bar. In other embodiments of the invention, the RGB three-color light can also be combined first using a dichroic color filter, and then shaped and / or angularly distributed.

[0082] In one embodiment of the present invention, a first light beam can also be obtained by combining a solid-state light source with a transparent fluorescent rod. The solid-state light source emits excitation light which is incident into the transparent fluorescent rod. A portion of this light passes directly through the transparent fluorescent rod and exits through the exit surface, while the remaining portion excites the transparent fluorescent rod to form fluorescence complementary to the excitation light, which then exits through the exit surface. The transparent fluorescent rod can be made into the shape of an angle-distribution converter.

[0083] Please see Figure 9 This is a schematic diagram of another modified embodiment of Embodiment 1 of the present invention. The single-panel liquid crystal projection device 100”' includes a white light source module 110”', a first wavelength angle beam splitter 120, a first microlens array 130, a liquid crystal display device 140, and a projection lens 150. Figure 9 In the modified embodiment shown, the numbering and Figure 3 The same parts are described in Embodiment 1. In this embodiment, the white light source module 110"' includes a solid-state light source array 117' and a light shaping device 119, wherein the solid-state light source array 117' is arranged in the same direction and is a laser diode array, and the light shaping device 119, which includes a compound eye lens pair, performs light homogenization and changes the divergence angle.

[0084] In this invention, when a laser is used directly as the light source of the white light source module, due to the small optical expansion and high energy density of the laser, beam expansion and collimation are often required. The smaller the optical expansion of the laser, the smaller the divergence angle of the laser exit port, and the higher the cost of the laser. Therefore, to improve the economic efficiency of productization of this invention, preferably, when the cross-sectional area of ​​the first beam is comparable to the effective pixel area of ​​the liquid crystal display device, the divergence half-angle of the first beam is not less than 0.014°.

[0085] Please see Figure 10 This is a schematic diagram of a second embodiment of the single-panel liquid crystal projection device of the present invention. The single-panel liquid crystal projection device 200 includes a white light source module 210, a first wavelength angle beam splitter 220, a first microlens array 230, a liquid crystal display device 240, a projection lens 250, and a second wavelength angle beam splitter 260.

[0086] The white light source module 210, the first wavelength angle beam splitter 220, the first microlens array 230, the liquid crystal display device 240, and the projection lens 250 can be referred to the descriptions of the white light source module 110 / 110' / 110” / 110”', the first wavelength angle beam splitter 120, the first microlens array 130, the liquid crystal display device 140, and the projection lens 150 in the above embodiments, and will not be repeated here. Compared with Embodiment 1, the main difference of Embodiment 2 is the addition of a second wavelength angle beam splitter 260. Because the first wavelength angle beam splitter 220 causes the blue light component and the red light component of the first beam to be offset at a certain angle to both sides relative to the principal optical axis of the green light component, it is not conducive to light collection. To solve this problem, the second wavelength angle beam splitter 260 is set to straighten the light on both sides, so that the principal optical axes of the red light, green light, and blue light components can be kept as parallel as possible.

[0087] In this embodiment, the second wavelength angle beam splitter 260 is disposed between the liquid crystal display device 240 and the projection lens 250 to make the main optical axes of the color beams of the color image parallel.

[0088] In a modified embodiment of this second embodiment, the second wavelength angle beam splitter can also be disposed between the first microlens array and the liquid crystal display device, used to make the color beams into a color beam array with red, green, and blue beams separated and each beam having parallel principal optical axes. In this embodiment, since the conversion from face-to-face distribution to angular distribution has been completed by the first microlens array, the separated red, green, and blue beams will not be re-merged into a white light beam. This embodiment only aims to change the direction of the principal optical axes of red and blue light. It should be noted that this technical solution is quite difficult. Since the distance from the first microlens array to the liquid crystal pixel array is generally within 1 mm, and the closer the distance, the better to avoid the influence of stray light generated by the seams between the microlens units, it is difficult to further place other optical elements in this space, and it is also difficult to ensure installation accuracy; moreover, the wavelength angle beam splitter has a certain refractive index, which complicates the calculation of optical path; in addition, the alignment of the second wavelength angle beam splitter and the first microlens array is also difficult. Therefore, the present invention preferably adopts the following... Figure 10 The arrangement shown places the second wavelength angle beam splitter 260 after the liquid crystal display device 240.

[0089] In this second embodiment or its variations, the second wavelength angle beam splitter is a diffractive optical device, such as a diffraction grating, a binary optical element, or other micro-optical structures that can achieve diffraction. The second wavelength angle beam splitter can also be a second microlens array. The second wavelength angle beam splitter can also be a dispersive element, such as a prism or a device containing a prism structure. For example, when the first wavelength angle beam splitter is a dispersive element, the second wavelength angle beam splitter is a dispersive element arranged in opposite directions. The two are arranged in a vertically flipped manner, so that each beam is equivalent to passing through a parallelepiped, thereby keeping the principal optical axis direction of the beam consistent.

[0090] Please see Figure 11 This is a schematic diagram of the optical path structure from the first microlens array 230 to the second wavelength angle beam splitter 260' in a modified embodiment of Example 2. The second wavelength angle beam splitter 260' is a second microlens array, which corresponds to the liquid crystal pixel array of the liquid crystal display device 240. Every three microlens units in the second microlens array 260' correspond to one microlens unit in the first microlens array 230. When the first microlens array 230 is a one-dimensional cylindrical lens array, the second microlens array 260' is also a one-dimensional cylindrical lens array, with each cylindrical lens in the second microlens array 260' corresponding to a row or column of liquid crystal pixels. When the first microlens array 230 is a two-dimensional cylindrical lens array, the second microlens array 260' is also a two-dimensional cylindrical lens array, with each cylindrical lens in the second microlens array 260' corresponding to one liquid crystal pixel.

[0091] Figure 11Only the red, green, and blue main wavelength beams incident on the first microlens array 230 parallel to the main optical axis are shown. Therefore, under the action of the first microlens array 230, the red, green, and blue main wavelength beams converge to a single point of the red, green, and blue liquid crystal pixels of the liquid crystal display device 240, respectively; the divergent light, offset at a certain angle relative to the main optical axis direction, converges to other points on the focal plane of the first microlens array 230, thereby filling the red, green, and blue liquid crystal pixels. For the green liquid crystal pixel located in the middle of the color pixel group, its incident light is vertically incident green light. After exiting, the main optical axis of the green light remains unchanged, and the corresponding microlens unit of the second microlens array 260' collimates it. By setting the liquid crystal pixel array of the liquid crystal display device 240 on the front focal plane of the second microlens array 260', the green light strictly along the main optical axis direction is absolutely parallel before the first microlens array 230 and after the second microlens array 260'. Considering that there is no absolutely parallel light in reality, the light beam before it enters the first microlens array 230 has a divergence angle. During the process from the first microlens array 230 to the liquid crystal display device 240, the light beam fills the liquid crystal pixels instead of being focused as a point / line on the liquid crystal pixels. As a result, the overall cross-sectional area of ​​the monochromatic light beam decreases and the divergence angle increases.

[0092] During the emission process from the liquid crystal display device 240 to the second microlens array 260', the beam cross-sectional area remains essentially unchanged, and the overall divergence angle of the beam remains constant, but the direction of the principal optical axis is altered. This is because the liquid crystal pixel array is positioned at the front focal plane of the second microlens array 260'. The light covering the liquid crystal pixels can be considered as the accumulation of countless zero-dimensional light-emitting points. The light emitted by these points is converted into perfectly parallel light by the second microlens array 260'. The superposition of countless perfectly parallel lights generated by countless zero-dimensional points constitutes the emitted light of the second microlens array 260'. For a single pixel, the angle of the parallel light generated by zero-dimensional points at different positions is different, which constitutes the divergence angle of the emitted light from the microlens unit of the second microlens array 260'. According to the conservation of optical extension, the size of the liquid crystal pixel array of the liquid crystal display device 240 corresponds to the size of the second microlens array 260', therefore, the divergence angles of their emitted light are essentially equal.

[0093] To ensure that the principal optical axis of the red light emitted from the second microlens array 260' is parallel to the principal optical axis of the green light, preferably, the line connecting the focal point of the red light parallel to the principal optical axis on the red liquid crystal pixel and the center of the microlens unit corresponding to the red liquid crystal pixel is exactly parallel to the principal optical axis of the green light. The situation for blue light is similar to that for red light; simply replacing the red light in the above description with blue light yields the technical solution for blue light.

[0094] Please see Figure 12This is a schematic diagram of the structure of a third embodiment of the single-panel liquid crystal projection device of the present invention. The single-panel liquid crystal projection device 300 includes a white light source module 310, a first wavelength angle beam splitter 320, a first microlens array 330, a liquid crystal display device 340, a projection lens 350, a second wavelength angle beam splitter 360, and a pixel offset device 370. The descriptions of the white light source module 310, the first wavelength angle beam splitter 320, the first microlens array 330, the liquid crystal display device 340, the projection lens 350, and the second wavelength angle beam splitter 360 can be found in the descriptions of the above embodiments and their variations.

[0095] Compared with the above embodiments, the main difference of this third embodiment is that a pixel offset device 370 is added and disposed in the outgoing light path of the liquid crystal display device 340. It is used to shift the light beam of the color image along a direction perpendicular to the optical axis, so that the color images at different shift positions are superimposed in time.

[0096] The pixel shifting device 370 can be a transparent flat-plate optical device whose rotation angle is controlled by current or voltage. When the transparent plate of the pixel shifting device 370 rotates by a certain angle, the light passing through the transparent plate is translated as a whole after being refracted twice. The transparent plate stays at the rotated position for a predetermined time and then rotates to another position. In one image frame cycle, the pixel shifting device 370 can include two or four stable states. The image is correspondingly split into two or four subframes. The human eye uses time integration to superimpose the captured two or four images, thereby forming a high-resolution image in the brain. It is understood that the pixel shifting device can also include more stable states to achieve higher resolution. This invention does not limit the number of pixel multiplications.

[0097] In other embodiments, the pixel shifting device can also be a liquid crystal birefringence device. By controlling the deflection angle of the liquid crystal molecules with voltage, the light passing through the liquid crystal birefringence device is translated, thereby achieving the effect of overall pixel shifting. The effect is similar to the mechanically rotating pixel shifting device described above, and will not be elaborated here.

[0098] In Embodiment 4 of the present invention, based on the above embodiments or their variations, a filter unit disposed in the optical path is further included. The filter unit is used to reduce the light component between the dominant wavelength of green light and the dominant wavelength of red light in the optical path and / or the filter unit is used to reduce the light component between the dominant wavelength of blue light and the dominant wavelength of green light in the optical path.

[0099] This filtering unit can be a single, integral filter that can be positioned in various locations along the optical path. For example, it can be placed within the white light source module to directly color correct the white light at the source; it can also be positioned between the white light source module and the first wavelength angle beam splitter, between the first wavelength angle beam splitter and the first microlens array, between the first microlens array and the liquid crystal display device, or between the liquid crystal display device and the projection lens. By setting up the filtering unit, the color coordinates of red, green, and blue can be adjusted, resulting in more vibrant image colors and a wider color gamut. Placing the filter in the upstream optical path of the liquid crystal display device can reduce the heat generated when light passes through the device.

[0100] The filter unit can also be a filter array corresponding to each liquid crystal pixel, filtering and color correcting the red, green, and blue light emitted from the red, green, and blue pixels respectively, thereby achieving a more refined spectral effect. This filter array can be achieved through arrayed coating, and the filter film layer can be either absorptive or reflective.

[0101] Please see Figure 13 This is the spectral curve after filtering. The filtered components are removed from the mixtures of red and green light, and green and blue light, thereby improving the color gamut. It can be understood that when a narrow-spectrum light source is used, such as a pure laser light source, the spectra of red, green, and blue light are separate, so a filtering unit is not necessary.

[0102] In Embodiment 5 of the present invention, based on the above embodiments or their variations, an absorption grid is further included, disposed between the first microlens array and the liquid crystal display device. Please refer to... Figure 14 This is a schematic diagram of the partial optical path structure from the first microlens array to the liquid crystal pixel array in Embodiment 5 of the single-panel liquid crystal projection device of the present invention. Before reaching the liquid crystal pixel array 41, light from the first microlens array 30 is partially absorbed by the absorption grid 43. The absorption grid includes an array of absorption and transmission areas; the black portion in the diagram represents the absorption area, which is located between the dominant green and red wavelengths of the color beam and / or between the dominant blue and red wavelengths of the color beam. For ease of explanation, this embodiment is accompanied by... Figure 13 Only the dominant green wavelength beam and a portion of the yellow Y beam, located between the dominant green and red wavelength beams, are shown. Since the wavelength of yellow Y is between that of green and red light, after passing through the first wavelength angle beam splitter, the angular offset of yellow light relative to green light is less than that of red light relative to green light. Therefore, the propagation path of yellow Y is between that of green and red light. By utilizing the spatial differences in the wavelength beams and correspondingly setting absorption grids, the filter film can be manufactured without complex coating processes, offering a cost advantage. Furthermore, by setting absorption grids, potential crosstalk can be further eliminated, further reducing pixel crosstalk.

[0103] In this embodiment, the absorption grid 43 is disposed on the liquid crystal display device and can simultaneously serve as a circuit conductor of the liquid crystal display device, corresponding precisely to the control circuit of the liquid crystal pixel unit, thus achieving two goals at once. It can be understood that in other embodiments of the present invention, the absorption grid can also be suspended relative to the liquid crystal pixel array, so that the heat generated by the absorption grid absorbing the light beam will not be directly conducted to the liquid crystal pixel array, thereby improving its reliability.

[0104] The absorption spectrum of absorption grating 43 can be referenced. Figure 13 In the above situation, by absorbing light through the absorption grid 43, complete absorption can be achieved in this area, and there is no problem of the transmittance curve changing with the angle, which is more reliable.

[0105] In Embodiment Six of the present invention, in order to solve the problem of color pixel separation and improve the color pixel resolution, the first wavelength angle beam splitter includes at least three partitions and a driving device. Under the drive of the driving device, each partition is located in the optical path of the first beam emitted from the white light source module at different times, so that the first wavelength angle beam splitter emits color beams with different red, green and blue arrangements at different times.

[0106] For example, in the above embodiments, the angles of the emitted light from the first wavelength angle beam splitter are arranged from left to right in the diagram as blue, green, and red, with green light in the center. This arrangement of the first wavelength angle beam splitter can be considered the first partition of the first wavelength angle beam splitter in Embodiment Six. In the second partition of the first wavelength angle beam splitter in Embodiment Six, the angles of the emitted light are arranged as red, blue, and green. In the third partition of the first wavelength angle beam splitter in Embodiment Six, the angles of the emitted light are arranged as green, red, and blue. The first, second, and third partitions are periodically located in the optical path, resulting in an alternating output of red, green, and blue light. This technical solution enables each liquid crystal pixel to emit red, green, and blue light at different times within an image frame, making the pixel a full-color pixel containing all red, green, and blue colors. With the same number of liquid crystal pixels, the number of image pixels is tripled.

[0107] It is understood that although three partitions are listed in Embodiment Six, there may be more than three partitions in other embodiments of the present invention, and this is not a limitation. In this type of embodiment, since the liquid crystal pixels do not correspond to a specific color, it is not advisable to set an array of filter layers behind the liquid crystal pixels.

[0108] In Embodiment Seven of the present invention, based on the above embodiments or their variations, a light mixing device located on the emission side of the liquid crystal display device is further included. Please refer to... Figure 15This is a partial optical path structure diagram of Embodiment 7 of the single-panel liquid crystal projection device of the present invention. The liquid crystal display device 740 includes a liquid crystal pixel array 741 and a light mixing device 744. The liquid crystal pixel array includes a plurality of color liquid crystal pixels, and each color liquid crystal pixel is defined as having at least three liquid crystal pixels. The light mixing device 744 includes a plurality of light mixing units, each light mixing unit corresponding to a color liquid crystal pixel, so that the light mixing device is used to mix the emitted light of each color liquid crystal pixel uniformly.

[0109] Specifically, in this embodiment seven, the light mixing device 744 includes a light mixing cavity 7441 and a scattering unit 7442. The light mixing cavity 7441 is used to confine the emitted light of the color liquid crystal pixel to propagate within the light mixing cavity, and then emit it through the scattering unit 7442, thereby achieving the effect of uniform light shaping, so that the emitted light of each color liquid crystal pixel is colored light including red light, green light and blue light components, and can be directly used as a color pixel.

[0110] In the technical solution of Embodiment Seven, since at least three liquid crystal pixels constitute one color liquid crystal pixel, the image resolution of this technical solution is not high. To further improve the resolution, in a modified embodiment of Embodiment Seven, a pixel shifting device can be further added and disposed in the outgoing light path of the liquid crystal display device. This device is used to shift the light beam of the color image emitted by the liquid crystal display device along a direction perpendicular to the optical axis, so that the color images at different shift positions are superimposed in sequence.

[0111] Please see Figure 16 This is a schematic diagram of the temporal overlay of images after pixel offset. Assume an image frame includes two image subframes. Within one image frame period T, the two sets of subframe images (dashed and solid lines) are displayed respectively in the first image frame period T1 and the second image frame period T2. The two are then overlaid to form a higher-resolution image. This embodiment illustrates one technical solution for the pixel offset device; more technical solutions can be found by referring to... Figure 12 The description of Embodiment 3 and its variations is omitted here.

[0112] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0113] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A single-panel liquid crystal projection device, characterized in that, include A white light source module is used to emit a first light beam, the first light beam including at least red light, green light and blue light components; The first wavelength angle beam splitter is used to make light of different wavelengths emerge at different angles. The first beam becomes a colored beam after passing through the first wavelength angle beam splitter. The first microlens array, composed of multiple microlens units, is disposed in the output light path of the wavelength angle beam splitter to converge the colored beam, so that the colored beam forms red, green and blue separated colored stripes or colored spots on the reference plane. A liquid crystal display device includes a liquid crystal pixel array comprising a plurality of liquid crystal pixels, the liquid crystal pixel array being disposed on the reference plane, wherein color stripes or color spots of different colors fall onto different liquid crystal pixels respectively, and the liquid crystal display device is used to modulate incident light to form a color image emission; A projection lens is used to project the color image emitted by the liquid crystal display device onto a predetermined position; Wherein, when the cross-sectional area of ​​the first beam is comparable to the effective pixel area of ​​the liquid crystal display device, the divergence half-angle of the first beam is not greater than 6°.

2. The single-panel liquid crystal projection device according to claim 1, characterized in that, When the cross-sectional area of ​​the first beam is comparable to the effective pixel area of ​​the liquid crystal display device, the divergence half-angle of the first beam is no greater than 3°.

3. The single-panel liquid crystal projection device according to claim 1, characterized in that, When the cross-sectional area of ​​the first beam is comparable to the effective pixel area of ​​the liquid crystal display device, the divergence half-angle of the first beam is no greater than 1.67°.

4. The single-panel liquid crystal projection device according to claim 1, characterized in that, When the cross-sectional area of ​​the first beam is comparable to the effective pixel area of ​​the liquid crystal display device, the divergence half-angle of the first beam is not less than 0.014°.

5. A single-panel liquid crystal projection device, characterized in that, include A white light source module is used to emit a first light beam, the first light beam including at least red light, green light and blue light components; A first wavelength angle beam splitter is used to split the first beam into colored beams of different wavelengths that propagate at different angles; The first microlens array, composed of multiple microlens units, is disposed in the output light path of the wavelength angle beam splitter to converge the colored beam, so that the colored beam forms red, green and blue separated colored stripes or colored spots on the reference plane. A liquid crystal display device includes a liquid crystal pixel array comprising a plurality of liquid crystal pixels, the liquid crystal pixel array being disposed on the reference plane, wherein color stripes or color spots of different colors fall onto different liquid crystal pixels respectively, and the liquid crystal display device is used to modulate incident light to form a color image emission; A projection lens is used to project the color image emitted by the liquid crystal display device onto a predetermined position; Wherein, when the cross-sectional area of ​​the first beam is comparable to the effective pixel area of ​​the liquid crystal display device, the divergence half-angle θ of the first beam satisfies the following relationship: Where n is the refractive index of the microlens unit, x is the size of the liquid crystal pixel, and L is the distance between the first microlens array and the liquid crystal pixel array.

6. The single-panel liquid crystal projection device according to any one of claims 1 to 5, characterized in that, The white light source module includes at least an LED light source and an angle distribution converter. The light emitted by the LED light source is converted by the angle distribution converter to obtain a first beam. Alternatively, the white light source module includes at least a laser fluorescent source and an angle distribution converter, wherein the light emitted by the laser fluorescent source is converted by the angle distribution converter to obtain a first beam; Alternatively, the white light source module includes a semiconductor solid-state light source array and a light shaping device, wherein the light emitted by the semiconductor solid-state light source array is shaped by the light shaping device to obtain a first beam.

7. The single-panel liquid crystal projection device according to claim 6, characterized in that, The white light source module also includes a polarization converter for emitting the first beam in a single polarization state.

8. The single-panel liquid crystal projection device according to any one of claims 1 to 5, characterized in that, The white light source module includes at least a white light emitting unit, a conical reflector, and a reflective polarization selection device arranged sequentially along the optical path. The smaller end of the conical reflector is the incident surface, and the larger end is the exit surface. Unpolarized white light emitted from the white light emitting unit is incident through the incident surface of the conical reflector. The light incident into the conical reflector is reflected by the sidewall of the conical reflector and then exits through the exit surface or directly. At least part of the light exiting the conical reflector is transmitted through the reflective polarization selection device and exits with a single polarization state, while part is reflected by the reflective polarization selection device and returns to the conical reflector.

9. The single-panel liquid crystal projection device according to any one of claims 1 to 5, characterized in that, It also includes a second wavelength angle beam splitter, which is disposed between the first microlens array and the liquid crystal display device, and is used to make the color beam into a color beam array with red, green and blue separated and the principal optical axes of each beam parallel; Alternatively, the second wavelength angle beam splitter is disposed between the liquid crystal display device and the projection lens to make the principal optical axes of the color beams of the color image parallel.

10. The single-panel liquid crystal projection device according to claim 9, characterized in that, The second wavelength angle beam splitter is a diffractive optical device, a second microlens array, or a dispersive element.

11. The single-panel liquid crystal projection device according to claim 9, characterized in that, The second wavelength angle beam splitter is a second microlens array, and every three microlens units of the second microlens array correspond to one microlens unit of the first microlens array.

12. The single-panel liquid crystal projection device according to any one of claims 1 to 5, characterized in that, It also includes a pixel offset device, which is disposed in the outgoing light path of the liquid crystal display device, for translating the light beam of the color image along a direction perpendicular to the optical axis, so that the color images at different translation positions are superimposed in sequence.

13. The single-panel liquid crystal projection device according to any one of claims 1 to 5, characterized in that, It also includes a filter unit disposed in the optical path, the filter unit being used to reduce the light component between the dominant wavelength of green light and the dominant wavelength of red light in the optical path and / or the filter unit being used to reduce the light component between the dominant wavelength of blue light and the dominant wavelength of green light in the optical path.

14. The single-panel liquid crystal projection device according to any one of claims 1 to 5, characterized in that, It also includes an absorption grid disposed between the first microlens array and the liquid crystal display device. The absorption grid includes an array of absorption areas and light-transmitting areas. The absorption area is disposed between the green main wavelength beam and the red main wavelength beam of the color beam and / or the absorption area is disposed between the blue main wavelength beam and the red main wavelength beam of the color beam.

15. The single-panel liquid crystal projection device according to claim 14, characterized in that, The absorption grid is disposed on the liquid crystal display device and also serves as a circuit wire of the liquid crystal display device.

16. The single-panel liquid crystal projection device according to any one of claims 1 to 5, characterized in that, The liquid crystal display device includes a polarizer, which is separately disposed from the liquid crystal pixel array.

17. The single-panel liquid crystal projection device according to any one of claims 1 to 5, characterized in that, The first microlens array is a one-dimensional cylindrical lens array, where each cylindrical lens corresponds to three rows or three columns of liquid crystal pixels; or The first microlens array is a two-dimensional cylindrical lens array, and each cylindrical lens corresponds to three liquid crystal pixels.

18. The single-panel liquid crystal projection device according to any one of claims 1 to 5, characterized in that, The liquid crystal pixel array includes a plurality of color liquid crystal pixels, each of the color liquid crystal pixels including at least three liquid crystal pixels, and the liquid crystal display device further includes a light mixing device located on its emission side, the light mixing device being used to mix the emitted light of each of the color liquid crystal pixels uniformly.

19. The single-panel liquid crystal projection device according to claim 18, characterized in that, It also includes a pixel offset device, which is disposed in the outgoing light path of the liquid crystal display device, for translating the light beam of the color image along a direction perpendicular to the optical axis, so that the color images at different translation positions are superimposed in sequence.

20. The single-panel liquid crystal projection device according to any one of claims 1 to 5, characterized in that, The first wavelength angle beam splitter includes at least three partitions and a driving device. Under the drive of the driving device, each partition is located in the optical path of the first beam at different times, so that the first wavelength angle beam splitter emits colored beams with different red, green and blue arrangements at different times.

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