WO2022052868A1 - 显示装置 - Google Patents

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Publication number
WO2022052868A1
WO2022052868A1 PCT/CN2021/116385 CN2021116385W WO2022052868A1 WO 2022052868 A1 WO2022052868 A1 WO 2022052868A1 CN 2021116385 W CN2021116385 W CN 2021116385W WO 2022052868 A1 WO2022052868 A1 WO 2022052868A1
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WIPO (PCT)
Prior art keywords
light
liquid crystal
color
display device
crystal display
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PCT/CN2021/116385
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English (en)
French (fr)
Inventor
胡飞
张翠萍
方元戎
李屹
Original Assignee
深圳光峰科技股份有限公司
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Publication of WO2022052868A1 publication Critical patent/WO2022052868A1/zh

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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B21/00—Projectors or projection-type viewers; Accessories therefor
    • G03B21/005—Projectors using an electronic spatial light modulator but not peculiar thereto
    • G03B21/006—Projectors using an electronic spatial light modulator but not peculiar thereto using LCD's
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/10—Beam splitting or combining systems
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/10—Beam splitting or combining systems
    • G02B27/1006—Beam splitting or combining systems for splitting or combining different wavelengths
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/10—Beam splitting or combining systems
    • G02B27/1086—Beam splitting or combining systems operating by diffraction only
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B3/00—Simple or compound lenses
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B3/00—Simple or compound lenses
    • G02B3/0006—Arrays
    • G02B3/0037—Arrays characterized by the distribution or form of lenses
    • G02B3/005—Arrays characterized by the distribution or form of lenses arranged along a single direction only, e.g. lenticular sheets
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/003—Light absorbing elements
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B21/00—Projectors or projection-type viewers; Accessories therefor
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B21/00—Projectors or projection-type viewers; Accessories therefor
    • G03B21/14—Details
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B21/00—Projectors or projection-type viewers; Accessories therefor
    • G03B21/14—Details
    • G03B21/20—Lamp housings
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B21/00—Projectors or projection-type viewers; Accessories therefor
    • G03B21/14—Details
    • G03B21/20—Lamp housings
    • G03B21/2006—Lamp housings characterised by the light source
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B21/00—Projectors or projection-type viewers; Accessories therefor
    • G03B21/14—Details
    • G03B21/20—Lamp housings
    • G03B21/2006—Lamp housings characterised by the light source
    • G03B21/2033—LED or laser light sources
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B21/00—Projectors or projection-type viewers; Accessories therefor
    • G03B21/14—Details
    • G03B21/20—Lamp housings
    • G03B21/2066—Reflectors in illumination beam
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B21/00—Projectors or projection-type viewers; Accessories therefor
    • G03B21/14—Details
    • G03B21/20—Lamp housings
    • G03B21/2073—Polarisers in the lamp house
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B21/00—Projectors or projection-type viewers; Accessories therefor
    • G03B21/14—Details
    • G03B21/20—Lamp housings
    • G03B21/208—Homogenising, shaping of the illumination light

Definitions

  • the present invention relates to the field of display technology, and in particular, to a display device.
  • Projection display system mainly includes lighting system, optomechanical system, projection lens and other main parts.
  • Spatial light modulators also known as "light valves" are crucial devices in optomechanical systems.
  • the light valve is usually a pixelated flat device, each pixel of which can independently control the incident illumination light by means of transmission or reflection, and then control the luminous flux of each pixel to form a display image.
  • Projection display systems can be roughly divided into reflective DMD (Digital Micro-Mirror Device) projection, transmissive LCD (Liquid Crystal Display) projection and reflective LCoS (Liquid Crystal Display) projections according to the type of spatial light modulator. Crystal on Silicon, liquid crystal on silicon) projection; according to the number of spatial light modulators, it can be divided into single-plate projection, double-plate projection and three-plate projection.
  • Three-plate projection requires three spatial light modulators, which modulate RGB three-color images respectively, and then synthesize the color image through the light combining element, and then project the color image through the projection lens.
  • the light combining element is usually a solid prism, which is large in volume and mass; on the other hand, the light combining element occupies the space of the projection light path from the spatial light modulator to the projection screen.
  • the three-plate projection has the characteristics of complex optical path, high cost, and high requirements for alignment accuracy. Therefore, the three-plate projection is not suitable for portable projection.
  • the optical path design of the double-plate projection is similar to that of the three-plate projection. Based on the same problem, the double-plate projection is also not suitable for portability.
  • Single-plate projection uses only a single light valve device, and only processes light intensity, not color.
  • the light valve is illuminated with red light, and the light valve transmits or reflects a red image; at time t2, green illumination light illuminates the light valve to display a green image; at time t3, blue illumination light light valve, showing a blue image.
  • the switching speed at t1, t2, and t3 is fast enough, thanks to the visual persistence effect of the human eye, the observer's eyes will mix the three monochrome images into a color image, thereby realizing color display. .
  • single DMD projection and single LCoS projection are currently dominated, and single-plate type with LCD as light valve is usually not considered. projection.
  • single DMD projection and single LCoS projection still have complex optical paths due to their reflective optical path characteristics, making it difficult to further reduce the volume.
  • US7046407B2 proposes a single-panel transmissive LCD projection scheme. 1, the light emitted by the white light bulb light source 14 is converted into parallel white light by the reflector 12, and the grating 16 converts the parallel white light into colored light beams of different colors and propagating in different angular directions (that is, the main optical axis of the red, green and blue light beams).
  • the colored light beams are converged by the single microlens array 18 and straightened by the grating 22 to become spatially separated colored light beams (ie, the red, green and blue light beams are not spatially coincident with each other), which are incident on the LCD 20 .
  • the LCD 20 modulates the incident color light beam to form a color image light separated by red, green and blue pixels every 1/3 frame time.
  • time superposition is realized, thereby forming a color image with overlapping red, green and blue pixels, which is projected by the projection lens 26 onto the screen 28 to form a large-screen display.
  • the present invention provides a single-panel LCD projection device with good display effect and high system efficiency, including a white light source module for emitting a white light source module.
  • the first light beam includes at least red light, green light and blue light components;
  • a first wavelength angle beam splitter is used to make light of different wavelengths exit at different angles, and the first light beam passes through the first wavelength The angle beam splitter becomes the color beam;
  • the first microlens array which is composed of a plurality of microlens units, is arranged on the light path of the outgoing light of the wavelength angle beam splitter, and is used for converging the color beam, so that the color beam is in the Forming color stripes or color spots separated from red, green and blue on the reference plane;
  • a liquid crystal display device including a liquid crystal pixel array including a plurality of liquid crystal pixels, the liquid crystal pixel array being arranged on the reference plane, and the color stripes of different colors Or the colored spots fall on different liquid crystal pixels respectively, and the liquid crystal display device is used to modulate the incident light to form a color image output;
  • the projection lens is used to project the color image output from the liquid crystal display device to a predetermined position;
  • the divergence half angle of the first light beam is not greater than 3°.
  • the divergence half angle of the first light beam is not greater than 1.67°.
  • the divergence half angle of the first light beam is not less than 0.014°.
  • 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 light, green light and blue light components; the first wavelength angle The beam splitter is used to make light of different wavelengths exit at different angles, and the first light beam becomes a color beam through the first wavelength angle beam splitter; the first microlens array is composed of a plurality of microlens units and is arranged in the The outgoing light path of the wavelength angle beam splitter is used for converging the colored light beams, so that the colored light beams form color stripes or colored spots separated from red, green and blue on the reference plane; the liquid crystal display device includes a plurality of liquid crystals.
  • a liquid crystal pixel array of pixels the liquid crystal pixel array is arranged on the reference plane, the colored stripes or colored spots of different colors fall on different liquid crystal pixels respectively, and the liquid crystal display device is used to modulate the incident light , forming a color image output; the projection lens is used to project the color image output from the liquid crystal display device to 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 satisfies the following relationship:
  • n is the refractive index of the microlens unit
  • x is the size of the liquid crystal pixel
  • L is the distance between the first microlens array and the liquid crystal pixel array.
  • the present invention includes the following beneficial effects: the first light beam including red light, green light and blue light components emitted by the white light source module passes through the action of the first wavelength angle beam splitter, so that the main light of the red, green and blue light beams is The axis propagates along different angles, and then passes through the first microlens array, so that the red, green and blue beams passing through the same microlens converge towards different spatial positions, so as to be incident on different liquid crystal pixels.
  • the surface distribution of the light on the liquid crystal display device can satisfy the The red, green and blue distributions are separated from each other, so that the light spots of different colors will not crosstalk to the pixels next door, and a color image with reduced pixel crosstalk is formed on the liquid crystal display device, which improves the 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, the light utilization rate of the overall system is improved, and the single-panel liquid crystal projection scheme has real practicability.
  • the white light source module includes at least an LED light source and an angular distribution converter, and the light emitted by the LED light source is converted by the angular distribution converter to obtain a first light beam; or, the white light source module It includes at least a laser fluorescent light source and an angular distribution converter, and the light emitted by the laser fluorescent light source is converted by the angular distribution converter to obtain a first light beam; or, the white light source module includes a semiconductor solid-state light source array and a light shaping device, After the light emitted by the semiconductor solid-state light source array is shaped by the light shaping device, a first light beam is obtained.
  • the white light source module further includes a polarization converter, which is used to make the first light beam exit in a single polarization state.
  • the white light source module at least comprises a white light emitting unit, a conical reflector and a reflective polarization selection device arranged in sequence along the light path, and the conical reflector has a smaller area at the end of the incident surface, The larger end of the conical reflector is the exit surface, and the unpolarized white light emitted by the white light emitting unit is incident through the incident surface of the conical reflector, and is incident on the conical reflector. The light is reflected by the sidewall of the conical reflector and then exits from the exit surface or exits directly. The exit light from the conical reflector is at least partially transmitted through the reflective polarization selection device and exits in a single polarization state , and part of it is reflected by the reflective polarization selective device back into the conical reflector.
  • a second wavelength angle beam splitter is further included, the second wavelength angle beam splitter is arranged between the first microlens array and the liquid crystal display device, and is used to make the color light beams red A color beam array with green and blue separation and the main optical axis of each beam being parallel; or, the second wavelength angle beam splitter is arranged between the liquid crystal display device and the projection lens, and is used to make each color of the color image
  • the principal optical axes of the beams are parallel.
  • the second wavelength angle beam splitter is a diffractive optical device, a second microlens array or a dispersive element.
  • the second wavelength angle beam splitter is a second microlens array, and every three microlens units of the second microlens array corresponds to one microlens unit of the first microlens array.
  • a pixel shifting device is further included, which is arranged on the outgoing light path of the liquid crystal display device, and is used to translate the light beam of the color image in a direction perpendicular to the optical axis, so that the color images at different translation positions are translated. Timing overlay.
  • it further includes a filter unit disposed in the optical path, 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 Used to reduce the light component between the dominant wavelength of blue light and the dominant wavelength of green light in the optical path.
  • it further includes an absorption grid disposed between the first microlens array and the liquid crystal display device, the absorption grid includes an array-type absorption area and a light transmission area, and the absorption area The absorption region is arranged between the green dominant wavelength beam and the red dominant wavelength beam of the colored light beam and/or the absorption region is arranged between the blue dominant wavelength beam and the red dominant wavelength beam of the colored light beam.
  • the absorption grid is disposed on the liquid crystal display device and simultaneously serves as a circuit lead of the liquid crystal display device.
  • the liquid crystal display device includes an analyzer, and the analyzer is provided separately from the liquid crystal pixel array.
  • the first microlens array is a one-dimensional distributed cylindrical lens array, and each cylindrical lens corresponds to three rows or three columns of the liquid crystal pixels; or the first microlens array is two-dimensional Distributed cylindrical lens array, each of the cylindrical lenses corresponds to three liquid crystal pixels.
  • the liquid crystal pixel array includes a plurality of color liquid crystal pixels, and each of the color liquid crystal pixels includes at least three liquid crystal pixels, the liquid crystal display device further includes a light mixing device on the exit side thereof, the The light mixing device is used for mixing the outgoing light of each color liquid crystal pixel uniformly.
  • a pixel shifting device is further included, which is arranged on the outgoing light path of the liquid crystal display device, and is used to translate the light beam of the color image in a direction perpendicular to the optical axis, so that the color images at different translation positions are translated. Timing overlay.
  • the first wavelength angle beam splitter includes at least three sub-regions and a driving device, and under the driving of the driving device, each of the sub-regions is located on the optical path of the first light beam in a time-division manner, In order to make the first wavelength angle beam splitter time-division output color light beams with different arrangements of red, green and blue.
  • FIG. 1 is a schematic diagram of the light path of a single-plate transmission LCD projection scheme in the prior art
  • FIG. 2 is a schematic diagram of the basic optical structure of the single-panel liquid crystal projection device of the present invention.
  • Embodiment 1 of the single-panel liquid crystal projection device of the present invention is a schematic structural diagram of Embodiment 1 of the single-panel liquid crystal projection device of the present invention.
  • FIG. 4 is a functional schematic diagram of a wavelength angle beam splitter
  • FIG. 5 is a schematic diagram of an optical path from a microlens to a liquid crystal pixel
  • FIG. 6 is a schematic diagram of an optical path from another microlens to a liquid crystal pixel
  • FIG. 7 is a schematic structural diagram of a modification of Embodiment 1 of the present invention.
  • FIG. 8 is a schematic structural diagram of still another modified embodiment of Embodiment 1 of the present invention.
  • FIG. 9 is a schematic structural diagram of still another modified embodiment of Embodiment 1 of the present invention.
  • Embodiment 2 is a schematic structural diagram of Embodiment 2 of the single-panel liquid crystal projection device of the present invention.
  • FIG. 11 is a schematic diagram of the optical path structure from the first microlens array to the second wavelength angle beam splitter of the single-panel liquid crystal projection device of the present invention.
  • Embodiment 3 is a schematic structural diagram of Embodiment 3 of the single-panel liquid crystal projection device of the present invention.
  • FIG. 14 is a schematic diagram of a partial optical path structure from the first microlens array to the liquid crystal pixel array according to the fifth embodiment of the single-panel liquid crystal projection device of the present invention.
  • FIG. 15 is a schematic diagram of a partial optical path structure of Embodiment 7 of the single-panel liquid crystal projection device of the present invention.
  • FIG. 16 is a schematic diagram of image timing stacking after pixel shifting.
  • the invention is based on solving the practicability problem of the single-panel liquid crystal projection technical scheme, and focuses on finding that the crux of the technical problem lies in the light source module - the light-emitting element of the previous light source has a large light-emitting surface and a large light-emitting angle, which is the etendue
  • a very large light source makes it impossible to achieve true color spot separation when the light source is matched with a microlens array and a liquid crystal display device.
  • the invention combines the white light source with small etendue with the technical solution of "white light color separation and then display by single-panel liquid crystal", so that the theoretical technical solution that stays on the paper has real practicability, so that the old Technology is reinvigorated with the infusion of new technologies.
  • FIG. 2 is a schematic diagram of the basic optical structure 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 , and a liquid crystal display device. 40 and projection lens 50.
  • the white light source module 10 emits a first light beam, and the first light beam includes at least red light, green light and blue light components.
  • the first light beam is incident on the first wavelength angle beam splitter 20, and is divided into color light beams with different wavelengths propagating at different angles, that is, red light, green light and blue light respectively propagating along different angles, and the main optical axis between each other is between There is an angle.
  • the colored light beams are incident on the first microlens array 30, wherein the first microlens array 30 is composed of a plurality of microlens units for converging the colored light beams.
  • the light beams and the blue light beams are respectively converged, so that the colored light beams form colored stripes or colored spots separated from red, green and blue on the reference plane.
  • the liquid crystal display device 40 is arranged on the reference plane, and includes a liquid crystal pixel array including a plurality of liquid crystal pixels, so that color stripes or color spots of different colors fall on 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 output, and then the projection lens 50 projects the color image output from the liquid crystal display device 40 to a predetermined position to form a display image.
  • the traditional bulb light source obtains so-called parallel white light through the wick and the reflector, and the optical principle used is to place the wick at the focal position of the parabolic reflector.
  • the optical model is ideally constructed, ie, treating the wick as a point light source.
  • the light-emitting part of the wick is wire-shaped, and its size is far from being regarded as a point light source.
  • the outgoing light of a wick with a solid angle of 4 ⁇ is converted to approximately
  • the divergence angle of parallel light is also very large, and only the light emitted from the point of the wick as the optical center has a good parallelism.
  • the size of the wick is larger, and the etendue thereof is larger, resulting in a larger light divergence angle under the same beam area.
  • the white light passes through the wavelength angle beam splitter, although the main optical axes of the lights of different wavelengths are staggered, the light with a large divergence angle will overlap. It overlaps with the light with a large divergence angle on the side of the red light close to the green light, causing the light of this spatial angle to be mixed into yellow light, and the image cannot be displayed correctly.
  • the present invention does not primarily pursue factors such as brightness, but focuses on the "etendue", a parameter that has nothing to do with brightness and power, and adopts a light source with a small etendue, so that the first light emitted by the white light source module 10 can be achieved.
  • the obtained colored light beams can realize less overlap between light beams of different wavelengths.
  • the light beams are further separated in space by the first microlens array 30 . On the plane, more clearly separated color stripes or color spots are obtained, and these color stripes or color spots can form a correctly displayed image through the liquid crystal display device 40 .
  • FIG. 3 is a schematic structural diagram of Embodiment 1 of the single-panel liquid crystal projection device 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 .
  • the white light source module 110 is configured to emit a first light beam, and the first light beam includes at least red light, green light and blue light components.
  • 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, which are arranged once along the optical path direction.
  • the end with the smaller area of the conical reflector 112 is the incident surface, and the end with the larger area is the outgoing surface, so that the unpolarized white light emitted by the white light emitting unit 111 enters the conical reflector through the incident surface, and then passes through the conical reflector. After reflection from the sidewall of the reflector, it is emitted or directly emitted from the emitting surface, so that the area of the outgoing light spot is larger than that of the incident light spot, thereby reducing the divergence angle of the light beam.
  • the conical reflector 112 in this embodiment is a solid conical light guide rod, and the light beam is reflected on the side surface of the conical reflector 112 by means of total reflection.
  • the conical reflector 112 may also be a hollow conical reflector composed of a reflecting plate/reflecting surface, which will not be repeated here.
  • the light emitted from the conical reflector 112 in this embodiment is unpolarized white light, which is incident on the reflective polarization selection device 113 along the optical path.
  • the polarization selection device 113 is reflected back into the conical reflector 112, reflected back and forth in the conical reflector 112, and then exits through the exit surface of the conical reflector 112 to reach the reflective polarization selection device 113, thereby improving the first utilization of a beam.
  • a structure such as a quarter wave plate may be arranged in the conical reflector to change the polarization state of the beam.
  • the reflective polarization selective device 113 may be a device such as a wire grid polarizer.
  • a collimating lens 114 is added after the reflective polarization selection device 113 to further collimate the first light beam so that it can smoothly enter the optical element downstream of the optical path. It can be understood that in other embodiments of the present invention, the collimating lens may not be provided, for example, when the first light beam from the upstream optical path satisfies a small divergence angle.
  • the first light beam from the white light source module 110 is incident on the first wavelength angle beam splitter 120 and is divided into color light beams with different wavelengths and propagating at different angles.
  • FIG. 4 it is a functional schematic diagram of the wavelength angle beam splitter of the present invention. As shown in the figure, the white light beam (the W big arrow in the figure) is incident on the wavelength angle beam splitter from the left side. The optical axis is incident perpendicular to the wavelength angle beam splitter.
  • the white light beam is split into colored beams, as shown in the figure, At least the red, green and blue light beams with different exit angles are split out (corresponding to the R/G/B large arrow beams in the figure).
  • Homogeneous beams are still quasi-parallel beams, that is, they propagate in the direction of the same main optical axis and have a certain divergence half angle.
  • red, green and blue ie RGB
  • dotted line solid line and dotted line respectively.
  • the beam arrow line in the middle of each represents the main optical axis, and the arrow lines on both sides represent the maximum divergence angle of the beam edge. of light.
  • white light is a continuous spectrum
  • the angular distribution of the main optical axis of each wavelength is also continuously changed. It is unavoidable that two kinds of light with different wavelengths exist in the exit direction of the same angle, but the main wavelength
  • the components of the mixed colors between them are relatively few, therefore, the present invention mainly considers the light near the main wavelengths of the three primary colors red, green and blue for display.
  • the white light is incident on the wavelength angle beam splitter in a manner that the main optical axis is vertical.
  • the first white light beam can also enter the wavelength angle beam splitter in an oblique manner.
  • the wavelength angle beam splitter has been described above in terms of its optical function.
  • the wavelength angle beam splitter can be a diffractive optical device, such as a diffraction grating, a binary optical element, and other micro-optical structures that can achieve diffraction effects.
  • the wavelength angle splitter can also be a dispersive element, such as a prism or a device containing a prismatic structure.
  • the colored light beams from the wavelength angle beam splitter 120 are incident on the first microlens array 130 on the optical path of the outgoing light.
  • the first microlens array 130 is composed of a plurality of microlens units, and each microlens unit divides the incident colored light beam into a sub-beam and converges it, so that the light of each color is converged into one area, so that the colored light beam is concentrated. Forms colored stripes or colored spots that separate red, green and blue on the reference plane.
  • the reference plane is at the focal plane position of the first microlens array. Due to factors such as assembly errors and the thickness of the liquid crystal layer, the reference plane can be centered on the focal plane at a distance of ⁇ set at 10%.
  • the first microlens array may be a one-dimensionally distributed cylindrical lens array, or may be a two-dimensionally distributed cylindrical lens array.
  • the colored light beams are converged into color stripes separated by red, green and blue; when the first microlens array is a two-dimensionally distributed cylindrical lens array, the colored light beams are converged into Red, green and blue colored spots isolated.
  • the liquid crystal display device 140 includes a liquid crystal pixel array 141 including a plurality of liquid crystal pixels and an analyzer 142.
  • the liquid crystal pixel array 141 is arranged on a reference plane so that color stripes or spots of different colors fall on different liquid crystal pixels respectively.
  • each cylindrical lens corresponds to three rows or three columns of liquid crystal pixels; when the first microlens array is a two-dimensionally distributed cylindrical lens array, each cylindrical lens corresponds to three LCD pixels.
  • the liquid crystal display device 140 is controlled by the circuit to modulate the polarization state of the incident light to obtain light with different polarization states, and then the analyzer 142 filters out part of the polarization state light to form a color image output.
  • the analyzer 142 may be a polarizing filter. Typically, the analyzer is placed next to the liquid crystal pixel array. In this embodiment, the analyzer 142 and the liquid crystal pixel array 141 are disposed separately to avoid direct thermal contact between the two, thereby avoiding the aging and damage of the analyzer 142 caused by the heat generated by the liquid crystal pixel array 141 . In other embodiments of the present invention, the analyzer 142 may also be disposed close to the liquid crystal pixel array 141 , as shown in the liquid crystal display device 240 of the second embodiment in FIG. 10 .
  • the projection lens 150 is disposed on the outgoing light path of the liquid crystal display device 140, and is used to project the color image to a predetermined position to form an image that can be viewed by the audience.
  • the projection lens 150 is composed of a plurality of lenses. It can be 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 requirements of the projection scene, and the projection lens can also include optical structures such as reflective surfaces. , and will not be repeated here.
  • FIG. 5 is a schematic diagram of the light path from the microlens to the liquid crystal pixel.
  • this figure only illustrates one microlens unit 30-1 of the first microlens array 30 and a group of corresponding liquid crystal pixels 41-1, wherein a group of liquid crystal pixels 41-1 includes three RGB pixels, forming a full color pixels.
  • the microlens unit 30-1 is a unit in the first microlens array composed of a one-dimensionally distributed cylindrical lens array, then the corresponding liquid crystal pixel group 41-1 is a row/column of pixels in a strip shape.
  • the viewing angle of Fig. 5 selects the viewing angle of the beam convergence, and only takes the green light G as an example to illustrate, wherein the solid line is the light of the green light G along the main optical axis direction, and the dotted line is the light of the green light G along the direction of the maximum emission half angle ⁇ ( For ease of illustration, only one side of the light is selected for description).
  • the main optical axis of the green light G is perpendicular to the liquid crystal display device.
  • the optical path from the incident surface of the first microlens array to the incident surface of the liquid crystal pixel array is studied.
  • the surface A close to the incident surface of the first microlens array is set as the reference light wave surface.
  • the incident surface of the first microlens array is infinitely close (the distance in the figure is an exaggerated drawing method, only for convenience of marking), so it can be considered that the cross-sectional area of the first light beam passing through the reference light wave surface A is equal to the cross-sectional area of the first microlens array.
  • the divergence half angle ⁇ of the first light beam passing through the reference light wavefront A is equal to the divergence half angle of the incident light of the first microlens array.
  • the size of the entire first micro-lens array is equivalent to the size of the liquid crystal pixel array. Therefore, the divergence half angle ⁇ is also equal to when the cross-sectional area of the first light beam is equal to the effective pixel area of the liquid crystal display device. Equivalent to the first beam divergence half angle.
  • the size of the single-color liquid crystal pixel is x
  • the distance between the first microlens array and the liquid crystal pixel array is L
  • the refractive index of the microlens unit 30-1 is n
  • the setting of the distance L between the first microlens array and the liquid crystal pixel array is affected by various factors.
  • the distance L is directly related to the focal length of the micro-lens unit of the first micro-lens array. Too small focal length will lead to an increase in the radius of curvature of the micro-lens unit, increase in cost, and increase in spherical aberration;
  • the smaller L the greater the influence of assembly error; in addition, there is also the influence of thermal distortion caused by the heat-generating liquid crystal pixel array on the heat transfer of the first microlens array.
  • the smaller the L the more obvious the heat transfer.
  • the size x of the liquid crystal pixel is affected by its own cost, the cost of the projection lens of the downstream optical path, etc., and an excessively large size cannot be used. Therefore, considering various factors, when the cross-sectional area of the first beam is equal to the effective pixel area of the liquid crystal display device, the first beam divergence half angle ⁇ of the present invention is not greater than 6°.
  • FIG. 6 is a schematic diagram of the light path from another microlens to the liquid crystal pixel.
  • the red light R is selected as the analysis light
  • the path of the green light and the numbers in the figure can refer to FIG. 5 .
  • the solid line is the light of the red light R along the main optical axis direction
  • the dotted line is the light of the red light R along the direction of the maximum emission half angle (for the convenience of description, only one side of the light is also selected for description).
  • the red light situation shown in FIG. 6 is similar to the green light situation shown in FIG. 5 . Therefore, the red light divergence half angle ⁇ of the first beam is Also meet not more than 6° or meet the conditions:
  • the red, green and blue components are in a coincident state, and their respective beam cross-sectional areas are the same as the beam divergence angles.
  • the propagation angle of each beam changes in the main optical axis, but the beam cross-sectional area can still be considered to be the same. Therefore, according to the conservation of etendue, the divergence angles of red light, green light and blue light are also the same. . Therefore, the divergence angle of the red, green and blue monochromatic light beams can be equal to the divergence angle of the white light of the first light beam before the angle splitting.
  • the light with the largest angle comes from the maximum divergence incident from the most edge of a microlens unit
  • the red light reaches the edge of the red liquid crystal pixel (that is, the edge of the entire red, green and blue color pixel) under the converging action of the microlens unit 30-1, the light is modulated by the red liquid crystal pixel and then exits,
  • the outgoing light becomes the maximum emission half angle of the liquid crystal display device 140 .
  • the projection lens 150 collects as much light emitted from the liquid crystal display device 140 as possible.
  • the collection angle requirement 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, and x, L, and n are also related to The divergence half-angle ⁇ of the first light beam is related.
  • the present invention preferably, when the cross-sectional area of the first light beam is equal to the effective pixel area of the liquid crystal display device, the divergence of the first light beam The half angle is not more than 3°. More preferably, 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 1.67°, which has better economical efficiency.
  • the blue and blue liquid crystal pixels are positioned symmetrically with the red and red liquid crystal pixels, so the present invention is only described with red light as an example, and the case of blue light basically refers to red light, no longer. Repeat.
  • 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 , which are arranged once along the optical path direction.
  • the white light emitting unit 111 may be an LED light source or a laser fluorescent light source (that is, the laser excites the fluorescent material to obtain white light).
  • the white light source module may include at least an LED light source and an angular distribution converter, and the light emitted by the LED light source is converted by the angular distribution converter to obtain a first light beam.
  • the angular distribution converter utilizes the principle of etendue conservation, so that the cross-sectional area of the outgoing beam is larger than that of the incident beam, thereby reducing the divergence angle of the beam.
  • the LED light source itself has a large divergence angle and cannot directly emit the available first beam, so it is necessary to cooperate with an angle distribution converter to obtain the first beam.
  • the conical reflector 112 and the collimating lens 114 in the first embodiment can be regarded as a kind of angle distribution converter.
  • the white light source module may further include at least a laser fluorescent light source and an angular distribution converter, and the light emitted by the laser fluorescent light source is converted by the angular distribution converter to obtain the first light beam.
  • FIG. 7 is a schematic structural diagram of a modification 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.
  • the parts numbered the same as those in FIG. 3 refer to the description in the first embodiment.
  • the white light source module 110' includes a laser fluorescent light source and an angular distribution converter.
  • the laser fluorescent light source includes an excitation light source 115 and a wavelength conversion device 116;
  • the angle distribution converter includes a conical reflector 112', and the conical reflector 112' includes a light entrance, and the excitation light emitted by the excitation light source 115 passes through the incident light The port is incident into the conical reflector 112 ′ and then to the wavelength conversion device 116 .
  • the excitation light source 115 is a blue laser (such as a blue laser diode or a blue laser diode array)
  • 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,
  • the white light has a large divergence angle, so a light beam with a large beam cross-sectional area and a small light divergence angle is 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 with the technical solution of the first embodiment, this modified embodiment replaces the light source, has higher luminous efficiency, and is suitable for application scenarios with higher brightness.
  • the wavelength conversion device 116 is a reflective wavelength conversion device, that is, the incident side of the excitation light and the emission side of the fluorescence are on the same side of the wavelength conversion device 116 .
  • the wavelength conversion device may also be a transmissive wavelength conversion device, and the excitation light source is disposed on a side of the wavelength conversion device away from the angle distribution converter.
  • the white light source module may further include a semiconductor solid-state light source array and a light shaping device, and the light emitted by the semiconductor solid-state light source array is shaped by the light shaping device to obtain the first light beam.
  • FIG. 8 is a schematic structural diagram of still 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 .
  • the parts numbered the same as those in FIG. 3 refer to the description in the first 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 ′.
  • the solid-state light source array 117 includes a red laser diode array, a green laser diode array, and a blue laser diode array.
  • the three are combined and homogenized by the light shaping device 118.
  • the light shaping device 118 can be, for example, an integrator rod.
  • the outgoing light of the light shaping device 118 is acted by the polarization converter 113' to obtain the first light beam emitted with a single polarization state
  • the polarization converter 113' can be a PCS array, which can be used in various embodiments to replace the reflective polarization selective device 113, but will cause etendue dilution.
  • the solid-state light source array can also be replaced with an LED light source array. Because of its large divergence angle, an angular distribution converter is still required to convert it into light with a small divergence angle, so as to facilitate the subsequent optical path. .
  • the RGB three-color solid-state light sources are directly coupled through the integrator rod.
  • the RGB three-color photosynthetic light can also be firstly combined through a dichroic sheet, and then shaping and/or angular distribution conversion are performed.
  • the first light beam can also be obtained by combining a solid-state light source with a transparent fluorescent rod, wherein the solid-state light source emits excitation light and is incident into the transparent fluorescent rod, and a part of it directly exits through the transparent fluorescent rod on the exit surface , after a part of the transparent fluorescent rod is excited, the fluorescent light complementary to the excitation light is formed, and then it is emitted on the output surface.
  • Transparent glow sticks can be made in the shape of an angular distribution converter.
  • FIG. 9 is a schematic structural diagram of still 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.
  • the parts numbered the same as those in FIG. 3 refer to the description in the first 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. light and changing the divergence angle.
  • the laser when the laser is directly used as the light-emitting source of the white light source module, due to the small etendue and high energy density of the laser, beam expansion and collimation of the laser are often required.
  • FIG. 10 is a schematic structural diagram of Embodiment 2 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 .
  • 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 refer to the white light source module 110/110'/110"/110"' in the above embodiment , the description of the first wavelength angle beam splitter 120 , the first microlens array 130 , the liquid crystal display device 140 , and the projection lens 150 will not be repeated here.
  • the main difference of the second embodiment is that the second wavelength angle beam splitter 260 is added.
  • the first wavelength and angle beam splitter 220 makes the blue light component and the red light component of the first light beam respectively offset by a certain angle relative to the main optical axis of the green light component on both sides, it is not conducive to light collection.
  • the second wavelength angle beam splitter 260 is set to straighten the light on both sides, so that the main optical axes of the red light, green light and blue light components can be kept as parallel as possible.
  • the second wavelength angle beam splitter 260 is disposed between the liquid crystal display device 240 and the projection lens 250, and is used to make the main optical axes of the color beams of the color image parallel.
  • the second wavelength angle beam splitter can also be arranged between the first microlens array and the liquid crystal display device, so as to make the color light beams become red, green and blue separated and the main optical axis of each light beam Array of parallel colored beams.
  • the separated red, green and blue light beams will not be recombined into white light beams.
  • This embodiment is only intended to change the principal optical axis directions of red and blue light.
  • the present invention preferably adopts the solution of disposing the second wavelength angle beam splitter 260 after the liquid crystal display device 240 as shown in FIG. 10 .
  • the second wavelength angle beam splitter is a diffractive optical device, such as a diffraction grating, a binary optical element, and other micro-optical structures that can realize diffraction; the second wavelength angle beam splitter also It can 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 The dispersive elements arranged in opposite directions are vertically flipped, so that each light beam is equivalent to passing through a parallelepiped, so that the main optical axis directions of the light beams remain the same.
  • FIG. 11 is a schematic diagram of the optical path structure from the first microlens array 230 to the second wavelength angle beam splitter 260 ′ in the modified embodiment of the second embodiment, wherein the second wavelength angle beam splitter 260 ′ is a second microlens
  • the second microlens array 260 ′ corresponds to the liquid crystal pixel array of the liquid crystal display device 240 , and every three microlens units of the second microlens array 260 ′ corresponds to one microlens unit of the first microlens array 230 .
  • the second microlens array 260' is also a one-dimensionally distributed cylindrical lens array, and each cylindrical lens of the second microlens array 260' corresponds to a row or a column of liquid crystals pixel;
  • the first microlens array 230 is a two-dimensionally distributed cylindrical lens array
  • the second microlens array 260' is also a two-dimensionally distributed cylindrical lens array, and each cylindrical lens of the second microlens array 260' corresponds to a liquid crystal pixel.
  • FIG. 11 only shows the red, green and blue dominant wavelength light beams incident on the first microlens array 230 parallel to the main optical axis. Therefore, under the action of the first microlens array 230, the red, green and blue dominant wavelength light beams are respectively converged to the liquid crystal.
  • One point of the red, green and blue liquid crystal pixels of the display device 240; the divergent light offset by a certain angle relative to the main optical axis direction converges to other points of the focal plane of the first microlens array 230, thereby filling the red, green and blue liquid crystal pixels.
  • the incident light is the vertically incident green light.
  • the main optical axis of the green light remains unchanged, and the corresponding microlens unit of the second microlens array 260' collimates it.
  • the liquid crystal pixel array of the liquid crystal display device 240 is arranged on the front focal plane of the second microlens array 260 ′, then the green light strictly along the main optical axis direction is before the first microlens array 230 and the second microlens array 260 ′. 'It's all absolutely directional light after that.
  • the light before incident on the first microlens array 230 has a divergence angle, and in the process from the first microlens array 230 to the liquid crystal display device 240, the light beam covers the liquid crystal pixels, Instead of focusing on a point/line on a liquid crystal pixel, the overall monochromatic beam cross-sectional area decreases and the divergence angle increases.
  • the cross-sectional area of the light beam is basically unchanged, and the overall divergence angle of the light beam is unchanged, but the direction of the main optical axis is changed.
  • the liquid crystal pixel array is arranged on the front focal plane of the second microlens array 260', and the light covering the liquid crystal pixels can be regarded as the accumulation of countless zero-dimensional light-emitting points, and the light emitted by these light-emitting points passes through the second microlens.
  • the action of the array 260' is converted into absolutely parallel light, and the superposition of countless absolutely parallel lights generated by countless zero-dimensional points is the outgoing light of the second microlens array 260'.
  • the angles of parallel light generated by zero-dimensional points at different positions are different, which also constitutes the divergence angle of the light emitted by the microlens units of the second microlens array 260'.
  • 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', so the divergence angles of the outgoing light of the two are substantially equal.
  • the focus of the red light parallel to the main optical axis of the red light on the red liquid crystal pixel is the same as the red liquid crystal pixel.
  • the line connecting the centers of the microlens units corresponding to the pixels is exactly parallel to the main optical axis of the green light.
  • FIG. 12 is a schematic structural diagram of Embodiment 3 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 shifting device 370 .
  • the description 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 implemented with reference to the above-mentioned embodiments and their variants. description of the example.
  • the main difference of the third embodiment is that a pixel shift device 370 is added, which is arranged on the outgoing light path of the liquid crystal display device 340, and is used to translate the light beam of the color image along the direction perpendicular to the optical axis. , so that the color images of different translation positions are superimposed in time sequence.
  • the pixel shifting device 370 can be a transparent flat optical device whose rotation angle is controlled by current or voltage.
  • the transparent flat plate of the pixel shifting device 370 When the transparent flat plate of the pixel shifting device 370 is rotated by a certain angle, the light passing through the transparent flat plate is refracted twice and then translated as a whole, transparent. The tablet stays in the rotated position for a predetermined time and then rotates to another position.
  • the pixel shifting device 370 may include 2 steady states or 4 steady states, the image is split into 2 subframes or 4 subframes in response, and the human eye uses the time integration function to detect the captured 2 subframes. Or 4 images are superimposed to form a high-resolution image in the brain.
  • the pixel shifting device may also include more stable states, so as to achieve higher resolution, and the present invention does not limit the number of pixels to multiply.
  • the pixel shifting device can also be a liquid crystal birefringence device, and the deflection angle of the liquid crystal molecules is controlled by a voltage, so as to translate the light passing through the liquid crystal birefringence device, so as to realize the effect of overall pixel shifting. Similar to the above-mentioned mechanically rotating pixel shifting device, details are not repeated here.
  • the filter unit is used to reduce the dominant wavelength of green light and the red light in the optical path.
  • the light component between the dominant wavelengths 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.
  • the filter unit can be an integral filter, which can be arranged in various positions of the optical path. For example, it can be set in the white light source module to directly modify the white light from the source, or it can be set 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, and between the liquid crystal display device and the projection lens.
  • the filter unit By setting the filter unit, the color coordinates of red, green and blue can be adjusted, so that the color of the image is more vivid and the color gamut is wider. Disposing the filter in the upstream optical path of the liquid crystal display device can reduce the heat generated when light passes through the liquid crystal display device.
  • the filter unit may also be a filter array corresponding to the liquid crystal pixels one-to-one, to filter the red, green and blue light emitted by the red, green and blue pixels respectively, so as to achieve a more refined spectral effect.
  • the filter array can be realized by array coating, and the filter layer can be of absorption type or reflection type.
  • FIG. 13 is a spectral curve after filtering.
  • the mixed color components between red light and green light, and green light and blue light are filtered out, thereby improving the color gamut.
  • the light source used is a narrow spectrum light source, such as a pure laser light source, the spectra of red light, green light, and blue light are separate spectra from each other, so the filter unit may not be provided.
  • an absorption grid is further included, which is arranged between the first microlens array and the liquid crystal display device.
  • FIG. 14 is a schematic diagram of a partial optical path structure from the first microlens array to the liquid crystal pixel array according to the fifth embodiment of the single-panel liquid crystal projection device of the present invention.
  • the light from the first microlens array 30 is partially absorbed by the absorption grid 43 before reaching the liquid crystal pixel array 41 .
  • the absorption grid includes an array of absorption areas and light-transmitting areas. The black part in the figure is the absorption area.
  • the absorption area is arranged between the green and red main wavelength beams of the color beam and/or is arranged in the color beam. Between the blue dominant wavelength beam and the red dominant wavelength beam of the light beam.
  • FIG. 13 in this embodiment only shows the green light main wavelength beam, and the partial beam of yellow light Y between the green light main wavelength light beam and the red light main wavelength light beam. Since the wavelength of yellow light Y is between green light and red light, after passing through the first wavelength angle beam splitter, the angular shift of yellow light relative to green light is smaller than that of red light relative to green light , so the propagation path of yellow light Y is between green light and red light.
  • the corresponding absorption grids are arranged, and the filter film can be manufactured without a complicated coating process, which has a cost advantage.
  • the possible crosstalk light can be further eliminated, and the pixel crosstalk can be further reduced.
  • the absorption grid 43 is disposed on the liquid crystal display device, and can simultaneously serve as a circuit wire of the liquid crystal display device, just corresponding to the control circuit of the liquid crystal pixel unit, thereby serving two birds with one stone. 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, improving its reliability. sex.
  • the spectrum absorbed by the absorption grid 43 can be referred to the above situation in FIG. 13 .
  • it can be completely absorbed in this area, and there is no problem of the transmittance curve changing with the angle, which is more reliable.
  • the first wavelength angle beam splitter in order to solve the problem of separation of color pixels and improve the resolution of color pixels, includes at least three partitions and a driving device. It is located on the optical path of the first light beam emitted by the white light source module, so that the first wavelength angle beam splitter emits color light beams with different arrangements of red, green and blue.
  • the angles of the outgoing light of the first wavelength angle beam splitter are in the order of blue, green and red from left to right in the figure, and the green light is located in the center to realize the first wavelength angle beam splitting of this arrangement.
  • the optical device can be used as the first partition of the first wavelength angle beam splitter of the sixth embodiment; in the second partition of the first wavelength angle beam splitter of the sixth embodiment, the angles of the outgoing light are in the order of red, blue and green. In the third division of the first wavelength angle beam splitter, the angles of the emitted light are in the order of green, red and blue.
  • the first subarea, the second subarea, and the third subarea are periodically located in the optical path in sequence, so as to obtain the outgoing light of red, green and blue light.
  • the technical solution enables each liquid crystal pixel to emit red, green and blue light at different timings in one image frame, so that the pixel becomes a color pixel including full colors of red, green and blue. With the same number of liquid crystal pixels, the number of image pixels is tripled.
  • FIG. 15 is a schematic diagram of a partial optical path structure 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, wherein the liquid crystal pixel array includes a plurality of color liquid crystal pixels, and a color liquid crystal pixel is defined as each color liquid crystal pixel including at least three liquid crystal pixels, and the light mixing device 744 includes a plurality of liquid crystal pixels.
  • the light mixing unit is in one-to-one correspondence with the color liquid crystal pixels, so that the light mixing device is used to mix the outgoing light of each color liquid crystal pixel uniformly.
  • 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 outgoing light of the color liquid crystal pixels to propagate in the light mixing cavity, and then pass through the scattering unit 7442.
  • Outgoing so as to achieve the effect of uniform light shaping, so that the outgoing light of each color liquid crystal pixel is color light including red light, green light and blue light components, which can be directly used as a color pixel.
  • a pixel shift device can be further added and arranged on the outgoing light path of the liquid crystal display device, so that the light beam of the color image emitted by the liquid crystal display device is perpendicular to the light beam. The direction of the axis is translated, so that the color images of different translation positions are sequentially superimposed.
  • FIG. 16 is a schematic diagram of image timing stacking after pixel offset. Assuming that an image frame includes two image subframes, within an image frame period T, two groups of subframe images with dotted lines and solid lines are displayed in the first image frame period T1 and the second image frame period T2 respectively, and the two are superimposed to form a higher resolution image. In this embodiment, a technical solution of the pixel offset device is listed. For more technical solutions, reference may be made to the description of Embodiment 3 and its variant embodiments in FIG. 12 , which will not be repeated here.

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Abstract

一种单板式液晶投影装置，包括白光光源模块（10），用于发出至少包括红光、绿光和蓝光成分的第一光束；第一波长角度分光器（20），第一光束经第一波长角度分光器（20）成为彩色光束；第一微透镜阵列（30），用于将彩色光束汇聚，使得彩色光束在参考平面上形成红绿蓝分离的彩色条纹或彩色斑点；液晶显示器件（40），包括包含多个液晶像素的液晶像素阵列，液晶像素阵列设置于参考平面上，不同颜色的彩色条纹或彩色斑点分别落入不同的液晶像素上，液晶显示器件（40）用于对入射光进行调制，形成彩色图像出射；投影镜头（50），用于将液晶显示器件（40）出射的彩色图像投射至预定位置；其中，当第一光束的截面积与液晶显示器件（40）的有效像素面积相当时，第一光束为小发散角光。

Description

显示装置 技术领域
本发明涉及显示技术领域，特别是涉及一种显示装置。
背景技术
随着社会经济的发展，以及信息化的不断推进，人们对大屏显示娱乐的需求日益旺盛。以客厅为例，近年来的市场销量表明，液晶电视尺寸具有逐渐增大的趋势。然而，信息时代的来临导致了时间碎片化，客厅不再是视频娱乐的唯一场所，而且由于液晶电视的体积大、重量大，其无法实现随时随地的应用。另一方面，虽然手机屏幕在尺寸方面已经有了长足的进步，甚至出现了更大尺寸的专为娱乐而生的智能平板，但是受限于其显示方式，难以实现真正的大屏显示。因此，要实现灵活的大屏显示，目前唯有投影的技术路线。
投影显示系统主要包括照明系统、光机系统、投影镜头等主要部分。光机系统中空间光调制器，也可以称为“光阀”，是至关重要的器件。光阀通常是像素化的平面设备，其每个像素可以通过透射或者反射的方式对入射照明光进行独立地调控，进而调控每个像素的光通量，形成显示图像。投影显示系统按照空间光调制器的类型，大致可分为反射型的DMD(Digital Micro-Mirror Device，数字微镜器件)投影、透射型的LCD(Liquid Crystal Display)投影和反射型的LCoS(Liquid Crystal on Silicon，硅基液晶)投影；按照空间光调制器的数量，又可以分为单板式投影、双板式投影和三板式投影。
三板式投影需要三个空间光调制器，分别调制RGB三色图像，然后通过合光元件合成彩色图像，再通过投影镜头将彩色图像投射出去。一方面，合光元件通常为实心棱镜，体积和质量大；另一方面，合光元件占据了空间光调制器至投影屏幕的投影光路空间。再加上三板式投影光路复杂、成本高、对位精度要求高等特点，因此，三板式投影不适于 便携式投影。双板式投影的光路设计与三板式投影类似，基于同样的问题，双板式投影也不适于便携。
单板式投影仅使用单个光阀器件,并且仅对光强进行处理，对颜色不进行处理。显示图像时，在t1时刻，采用红光照明光照射光阀，光阀透射或反射显示红色图像；在t2时刻，绿色的照明光照射光阀，显示绿色的图像；在t3时刻，蓝色的照明光照射光阀，显示蓝色图像。当t1、t2、t3三个时刻切换速度足够快的情况下，得益于人眼的视觉暂留效果，观察者的眼睛会将三个单色的图像混合成一个彩色图像，进而实现彩色显示。该种光学架构的投影，首先，如果采用白光光源，那么在任意时刻都只有红、绿、蓝中的一个单色光源可以被利用，即显示红色图像时，绿色和蓝色需要从光源滤除，会导致投影系统的光学效率低；其次，三色图像需要在时序上切换的速度足够快，因此需要光阀器件的刷新率/响应时间足够快，否则观察者就可能看到颜色分离(Color breakup)的图案，或在两种颜色的边界处观察到类似彩虹的图案。由于DMD的响应时间仅15μs，LCoS的响应时间约1.5ms，而LCD的响应时间通常＞7ms，因此目前以单DMD投影和单LCoS投影为主，通常不考虑以LCD为光阀的单板式投影。然而，单DMD投影和单LCoS投影由于其反射型光路的特点，仍是光路复杂，难以进一步缩小体积。
为了克服白光光源单板式投影的光利用率低的难题，同时解决颜色分离的问题，美国专利US7046407B2提出了一种单板式透射LCD投影方案。请参见图1，白光灯泡光源14发出的光经反光杯12转换为平行白光，光栅16将该平行白光转换为不同颜色沿不同角度方向传播的彩色光束(即红绿蓝光的光束的主光轴角度不同)，该彩色光束经单微透镜阵列18汇聚和光栅22拉直后，成为空间分离的彩色光束(即红绿蓝光束彼此空间不重合)，入射于LCD20。而后，LCD20对入射的彩色光束进行调制，每1/3帧的时间内形成一红绿蓝像素分离的彩色图像光，在摆动板24的作用下，每三个1/3帧彩色图像光在空间错位的情况下实现时间叠加，从而形成1帧红绿蓝像素重合的彩色图像，被投影镜头26投影至屏幕28上形成大屏显示。该技术方案虽然似乎在理论上提供了单板式LCD投影的可能性，然而在近约二十年间从未出现相关实际产 品，该类技术方案的专利也纷纷因不再维持而早早失效，可见该技术路线存在严重的现实可行性问题。本发明相关研发人员经研究发现，该技术方案在应用中往往会有像素串扰、图像显示混乱的问题，而且整个光学系统的效率很低，要达到可用的显示亮度，需要非常高的光源功率，而伴随高功率的光源而来的，是更大的光学系统、散热系统的体积和成本，以及更严重的像素串扰。
发明内容
针对上述现有技术的单板式LCD投影装置的像素串扰、实际可行性差的缺陷，本发明提供一种显示效果好、系统效率高的单板式液晶投影装置，包括白光光源模块，用于发出第一光束，所述第一光束至少包括红光、绿光和蓝光成分；第一波长角度分光器，用于使不同波长的光沿不同角度出射，所述第一光束经所述第一波长角度分光器成为彩色光束；第一微透镜阵列，由多个微透镜单元组成，设置于所述波长角度分光器的出射光光路上，用于将所述彩色光束汇聚，使得所述彩色光束在参考平面上形成红绿蓝分离的彩色条纹或彩色斑点；液晶显示器件，包括包含多个液晶像素的液晶像素阵列，所述液晶像素阵列设置于所述参考平面上，不同颜色的所述彩色条纹或彩色斑点分别落入不同的液晶像素上，所述液晶显示器件用于对入射光进行调制，形成彩色图像出射；投影镜头，用于将所述液晶显示器件出射的彩色图像投射至预定位置；其中，当所述第一光束的截面积与所述液晶显示器件的有效像素面积相当时，所述第一光束的发散半角不大于6°。
在一个实施方式中，当所述第一光束的截面积与所述液晶显示器件的有效像素面积相当时，所述第一光束的发散半角不大于3°。
在一个实施方式中，当所述第一光束的截面积与所述液晶显示器件的有效像素面积相当时，所述第一光束的发散半角不大于1.67°。
在一个实施方式中，当所述第一光束的截面积与所述液晶显示器件的有效像素面积相当时，所述第一光束的发散半角不小于0.014°。
在一个实施方式中，本发明提供一种单板式液晶投影装置，包括白光光源模块，用于发出第一光束，所述第一光束至少包括红光、绿光和 蓝光成分；第一波长角度分光器，用于使不同波长的光沿不同角度出射，所述第一光束经所述第一波长角度分光器成为彩色光束；第一微透镜阵列，由多个微透镜单元组成，设置于所述波长角度分光器的出射光光路上，用于将所述彩色光束汇聚，使得所述彩色光束在参考平面上形成红绿蓝分离的彩色条纹或彩色斑点；液晶显示器件，包括包含多个液晶像素的液晶像素阵列，所述液晶像素阵列设置于所述参考平面上，不同颜色的所述彩色条纹或彩色斑点分别落入不同的液晶像素上，所述液晶显示器件用于对入射光进行调制，形成彩色图像出射；投影镜头，用于将所述液晶显示器件出射的彩色图像投射至预定位置；其中，当所述第一光束的截面积与所述液晶显示器件的有效像素面积相当时，所述第一光束的发散半角θ满足以下关系：
Figure PCTCN2021116385-appb-000001
其中n为所述微透镜单元的折射率，x为所述液晶像素大小，L为所述第一微透镜阵列与所述液晶像素阵列的距离。
与现有技术相比，本发明包括如下有益效果：白光光源模块出射的包含红光、绿光和蓝光成分的第一光束经过第一波长角度分光器的作用，使得红绿蓝光束的主光轴沿不同角度传播，再经过第一微透镜阵列，使得通过同一微透镜的红绿蓝光束分别朝向不同的空间位置汇聚，从而入射到不同的液晶像素上，通过限定第一光束的发散半角大小，使其满足小发散半角的条件，使得在第一光束通过白光光源模块与液晶显示器件之间的光学器件、将部分面分布转换为角分布时，液晶显示器件上的光的面分布能满足红绿蓝分布彼此分离，从而使得不同颜色的光斑不会串扰到隔壁像素，在液晶显示器件上形成减少了像素串扰的彩色图像，提高了显示质量；同时，通过减少第一光束的发散半角，提高了各光学器件的能量传递效率和投影镜头的光收集效率，提高了整体系统的光利用率，使得单板式液晶投影方案得以具有真正的实用性。
在一个实施方式中，所述白光光源模块至少包括LED光源和角分布转换器，所述LED光源发出的光经所述角分布转换器转换后，得到第一光束；或者，所述白光光源模块至少包括激光荧光光源和角分布转换器，所述激光荧光光源发出的光经所述角分布转换器转换后，得到第一光束； 或者，所述白光光源模块包括半导体固态光源阵列和光整形装置，所述半导体固态光源阵列发出的光经所述光整形装置整形后，得到第一光束。
在一个实施方式中，所述白光光源模块还包括偏振转换器，用于使所述第一光束以单一偏振态出射。
在一个实施方式中，所述白光光源模块至少包括沿光路方向依次设置的白光发光单元、锥形反射器和反射式偏振选择器件，所述锥形反射器的面积较小的一端为入射面，所述锥形反射器的面积较大的一端为出射面，所述白光发光单元出射的非偏振白光经所述锥形反射器的所述入射面入射，入射到所述锥形反射器内的光经所述锥形反射器的侧壁反射后由所述出射面出射或直接出射，所述锥形反射器的出射光中，至少部分透射所述反射式偏振选择器件后以单一偏振态出射，部分被所述反射式偏振选择器件反射后回到所述锥形反射器内。
在一个实施方式中，还包括第二波长角度分光器，所述第二波长角度分光器设置于所述第一微透镜阵列与所述液晶显示器件之间，用于使所述彩色光束成为红绿蓝分离且各光束的主光轴平行的彩色光束阵列；或者，所述第二波长角度分光器设置于所述液晶显示器件与所述投影镜头之间，用于使所述彩色图像的各色光束的主光轴平行。
在一个实施方式中，所述第二波长角度分光器为衍射光学器件、第二微透镜阵列或色散元件。
在一个实施方式中，所述第二波长角度分光器为第二微透镜阵列，所述第二微透镜阵列的每三个微透镜单元对应所述第一微透镜阵列的一个微透镜单元。
在一个实施方式中，还包括像素偏移装置，设置于所述液晶显示器件的出射光路上，用于使所述彩色图像的光束沿垂直于光轴的方向平移，使得不同平移位置的彩色图像时序叠加。
在一个实施方式中，还包括设置于光路中的滤光单元，所述滤光单元用于减少光路中的绿光主波长与红光主波长之间的光成分及/或所述滤光单元用于减少光路中的蓝光主波长与绿光主波长之间的光成分。
在一个实施方式中，还包括吸收栅格，设置于所述第一微透镜阵列与所述液晶显示器件之间，所述吸收栅格包括阵列式的吸收区与透光区， 所述吸收区设置于所述彩色光束的绿光主波长光束与红光主波长光束之间及/或所述吸收区设置于所述彩色光束的蓝光主波长光束与红光主波长光束之间。
在一个实施方式中，所述吸收栅格设置于所述液晶显示器件上，同时用作所述液晶显示器件的电路导线。
在一个实施方式中，所述液晶显示器件包括检偏器，所述检偏器与所述液晶像素阵列分离设置。
在一个实施方式中，所述第一微透镜阵列为一维分布的柱透镜阵列，每一所述柱透镜对应三行或三列所述液晶像素；或者所述第一微透镜阵列为二维分布的柱透镜阵列，每一所述柱透镜对应三个液晶像素。
在一个实施方式中，所述液晶像素阵列包括多个彩色液晶像素，每一所述彩色液晶像素至少包括三个液晶像素，所述液晶显示器件还包括位于其出射侧的混光装置，所述混光装置用于将每一所述彩色液晶像素的出射光混合均匀。
在一个实施方式中，还包括像素偏移装置，设置于所述液晶显示器件的出射光路上，用于使所述彩色图像的光束沿垂直于光轴的方向平移，使得不同平移位置的彩色图像时序叠加。
在一个实施方式中，所述第一波长角度分光器包括至少三个分区及一个驱动装置，在所述驱动装置的驱动下，各所述分区分时的位于所述第一光束的光路上，以使所述第一波长角度分光器分时的出射红绿蓝排列方式不同的彩色光束。
附图说明
图1为现有技术中一种单板式透射LCD投影方案的光路示意图；
图2为本发明单板式液晶投影装置的基本光学架构示意图；
图3为本发明单板式液晶投影装置的实施例一的结构示意图；
图4为波长角度分光器的功能示意图；
图5为微透镜至液晶像素的光路示意图；
图6为另一微透镜至液晶像素的光路示意图；
图7为本发明实施例一的变形实施例的结构示意图；
图8为本发明实施例一的又一变形实施例的结构示意图；
图9为本发明实施例一的又一变形实施例的结构示意图；
图10为本发明单板式液晶投影装置的实施例二的结构示意图；
图11为本发明单板式液晶投影装置的第一微透镜阵列到第二波长角度分光器的光路结构示意图；
图12为本发明单板式液晶投影装置的实施例三的结构示意图；
图13为本发明单板式液晶投影装置的滤光单元滤光后的光谱曲线；
图14为本发明单板式液晶投影装置实施例五的第一微透镜阵列到液晶像素阵列的局部光路结构示意图；
图15为本发明单板式液晶投影装置的实施例七的局部光路结构示意图。
图16为像素偏移后的图像时序叠加示意图。
具体实施方式
本发明立足于解决单板式液晶投影技术方案的实用性问题，重点发现了技术问题的症结在于光源模块——以往的光源的发光元件发光面又大、发光角度又大，即为光学扩展量非常大的光源，导致光源与微透镜阵列、液晶显示器件匹配时，无法实现真正的彩色光斑分离。本发明通过将具有小光学扩展量的白光光源与“白光色分离后通过单板式液晶显示”的技术方案相结合，使得停留在纸面上的理论技术方案获得了真正的实用性，使老技术在新技术的注入下重新焕发活力。
请参见图2，为本发明单板式液晶投影装置的基本光学架构示意图，单板式液晶投影装置包括白光光源模块10、第一波长角度分光器20、第一微透镜阵列30、液晶显示器件40和投影镜头50。白光光源模块10发出第一光束，第一光束至少包括红光、绿光和蓝光成分。第一光束入射到第一波长角度分光器20，被分为不同波长沿不同角度传播的彩色光束，即红光、绿光和蓝光分别沿不同的角度传播，彼此之间的主光轴之间存在夹角。该彩色光束入射到第一微透镜阵列30，其中第一微透镜阵列30由多个微透镜单元组成，用于将彩色光束汇聚，每一微透镜单元对入射于其的红光光束、绿光光束和蓝光光束分别进行汇聚，使得彩色光束在参考平面上形成红绿蓝分离的彩色条纹或者彩色斑点。液晶显示 器件40就设置在参考平面上，包括包含多个液晶像素的液晶像素阵列，使得不同颜色的彩色条纹或彩色斑点分别落入不同的液晶像素上，在驱动信号的控制下，液晶显示器件40对入射光进行调制，形成彩色图像出射，而后，投影镜头50将液晶显示器件40出射的彩色图像投射到预定位置，形成显示图像。
该光学架构下，传统的灯泡光源通过灯芯和反光杯得到所谓的平行白光，利用的光学原理是将灯芯置于抛物面反光杯的焦点位置。然而该光学模型是在理想情况下搭建的，即，将灯芯视为点光源。实际情况下，灯芯的发光部为丝线状，尺寸远不能视为点光源，即使对反光杯的反射曲面进行优化设计，由于光学扩展量守恒，4π立体角发光的灯芯的出射光在转换为近似平行光时的发散角也非常大，只有灯芯的视作光学中心的点发出的光能具有较好的平行度。特别地，采用越高功率的灯泡光源，灯芯的尺寸越大，其光学扩展量越大，导致在相同的光束面积下的光发散角越大。进一步地，在该白光通过波长角度分光器时，不同波长的光虽然主光轴相互错开，然而大发散角的光会出现重叠，例如绿光的靠近红光一侧的大发散角的光会与红光的靠近绿光一侧的大发散角的光重叠，导致该空间角度的光混合为黄光，不能正确的显示图像。
同样的光学架构，本发明并不首要追求亮度等因素，而是着眼于“光学扩展量”这一与亮度、功率无关的参数，采用小光学扩展量的光源，使得白光光源模块10发出的第一光束在通过第一波长角度分光器20之后，得到的彩色光束能够实现不同波长的光束彼此之间的重叠更少，然后，通过第一微透镜阵列30，进一步对光束进行空间分离，在参考平面上得到彼此分割更清晰的彩色条纹或彩色斑点，这些彩色条纹或彩色斑点就能够通过液晶显示器件40形成正确显示的图像。
下面结合附图和实施方式对本发明实施例进行详细说明。
请参见图3，为本发明的单板式液晶投影装置的实施例一的结构示意图。单板式液晶投影装置100包括白光光源模块110、第一波长角度分光器120、第一微透镜阵列130、液晶显示器件140和投影镜头150。
白光光源模块110用于发出第一光束，第一光束至少包括红光、绿光和蓝光成分。在本实施例中，白光光源模块110包括沿光路方向一次 设置的白光发光单元111、锥形反射器112、反射式偏振选择器件113和准直透镜114。
锥形反射器112的面积较小的一端为入射面，面积较大的一端为出射面，以使白光发光单元111发射的非偏振白光经入射面入射到锥形反射器内部之后，经锥形反射器的侧壁反射后由出射面出射或直接出射，使得出射光斑的面积大于入射光斑的面积，从而减小了光束的发散角。本实施例中的锥形反射器112为实心锥形导光棒，光束通过全反射的方式在锥形反射器112的侧面反射。在本发明的其他实施方式中，锥形反射器112也可以为由反射板/反射面构成的空心锥形反射器，此处不再赘述。
本实施例的锥形反射器112的出射光为非偏振白光，沿光路入射到反射式偏振选择器件113，部分光透射反射式偏振选择器件113后以单一偏振态继续出射，部分光被反射式偏振选择器件113反射后回到锥形反射器112内，在锥形反射器112内来回反射，重新经锥形反射器112的出射面出射而到达反射式偏振选择器件113，从而提高了对第一光束的利用率。为了使得回收后的第一光束能够减少回收次数，可以在锥形反射器内设置如1/4波片的结构，对光束的偏振态进行改变。在本发明中，反射式偏振选择器件113可以是例如线栅偏振片的装置。
本实施例的白光光源模块110在反射式偏振选择器件113后增加了准直透镜114，以进一步对第一光束进行准直，使其顺利进入光路下游的光学元件。可以理解，在本发明的其他实施方式中，也可以不设置准直透镜，例如，当来自上游光路的第一光束满足小发散角的情况下。
继续参见图3，来自白光光源模块110的第一光束入射到第一波长角度分光器120，被分为不同波长沿不同角度传播的彩色光束。同时参见图4，为本发明的波长角度分光器的功能示意图。如图所示，白光光束(图中W大箭头)从左侧入射到波长角度分光器，该白光光束具体为一发散半角为β的准平行光束(见图中虚线圆内所示)，主光轴垂直于波长角度分光器入射。经波长角度分光器的作用，不同波长的光在波长角度分光器内的传播路径不同，沿不同角度出射，使得在波长角度分光器的出射侧，白光光束分裂为彩色光束，如图所示，至少分裂出出射角 度不同的红绿蓝三色光束(对应图中R/G/B大箭头光束)。同色光束仍为准平行光束，即沿同一主光轴的方向传播，且具有一定的发散半角。如图右侧虚线圆内所示，红绿蓝(即RGB)分别用点划线、实线和虚线表示，各自中间的光束箭头线表示主光轴，两侧箭头线表示光束边缘最大发散角的光线。由于在本发明的某些实施方式中，白光为连续光谱，导致各波长的主光轴角度分布也是连续变化的，不可避免的使得在同一角度出射方向存在不同波长的两种光，但是主波长之间的混合色的成分相对较少，因此，本发明主要考虑用于显示的三基色红绿蓝主波长附近的光。如图4所述的方案中，以白光主光轴垂直的方式入射到波长角度分光器，在本发明的其他实施方式中，第一光束白光也可以以倾斜入射的方式进入波长角度分光器。
以上从光学功能上对波长角度分光器进行了描述。具体地，波长角度分光器可以为衍射光学器件，如衍射光栅、二元光学元件、以及其他可以实现衍射作用的微光学结构。波长角度分光器还可以为色散元件，如棱镜或者包含棱镜结构的器件。
来自波长角度分光器120的彩色光束入射到出射光光路上的第一微透镜阵列130。第一微透镜阵列130由多个微透镜单元组成，每个微透镜单元将入射的彩色光束分割出一个子光束，并将其汇聚，使得每一颜色的光汇聚到一个区域，从而使得彩色光束在参考平面上形成红绿蓝分离的彩色条纹或彩色斑点。在本发明中，参考平面在第一微透镜阵列的焦平面位置，由于装配误差等因素，同时考虑到液晶层的厚度等问题，参考平面可在以焦平面为中心距离第一微透镜阵列±10％的位置处设置。
在本发明中，第一微透镜阵列可以为一维分布的柱透镜阵列，还可以为二维分布的柱透镜阵列。当第一微透镜阵列为一维分布的柱透镜阵列时，将彩色光束汇聚成为红绿蓝分离的彩色条纹；当第一微透镜阵列为二维分布的柱透镜阵列时，将彩色光束汇聚成红绿蓝分离的彩色斑点。
液晶显示器件140包括包含多个液晶像素的液晶像素阵列141和检偏器142，液晶像素阵列141设置于参考平面上，使得不同颜色的彩色条纹或彩色斑点分别落入不同的液晶像素上。当第一微透镜阵列为一维分布的柱透镜阵列时，每一柱透镜对应三行或三列液晶像素；当第一微 透镜阵列为二维分布的柱透镜阵列，每一柱透镜对应三个液晶像素。
通过电路控制液晶显示器件140，使其对入射光的偏振态进行调制，得到包含不同偏振态的光，再经过检偏器142滤除部分偏振态的光，从而形成彩色图像出射。检偏器142可以为偏振滤光片。通常地，检偏器紧贴液晶像素阵列设置。在本实施例中，将检偏器142与液晶像素阵列141分离设置，避免了两者直接的热接触，从而避免液晶像素阵列141产生的热量造成检偏器142的老化、损坏。在本发明的其他实施方式中，检偏器142也可以贴近液晶像素阵列141设置，如图10中的实施例二的液晶显示器件240所示。
投影镜头150设置在液晶显示器件140的出射光路上，用于将彩色图像投射至预定位置，形成可供观众观看的图像。本实施例中，投影镜头150由多个透镜组成。可以理解，附图中的投影镜头包含的透镜数量不对本发明投影镜头包含的透镜数量构成限定，本领域技术人员可根据投影场景需求对产品镜头进行设计，投影镜头还可以包括反射曲面等光学结构，此处不再赘述。
在本发明类似光学架构中，像素串扰问题主要发生在第一微透镜阵列30到液晶显示器件40的过程中，本发明人对此进行了详细的研究。请参见图5，为微透镜至液晶像素的光路示意图。为便于说明，该图仅示意出第一微透镜阵列30的一个微透镜单元30-1及其对应的一组液晶像素41-1，其中一组液晶像素41-1包括RGB三像素，构成一完整的彩色像素。(若微透镜单元30-1为一维分布的柱透镜阵列组成的第一微透镜阵列中的一个单元，那么对应的液晶像素组41-1则为长条形的一行/列像素。)
图5的视角选择对光束汇聚的视角，仅以绿光G为例进行说明，其中实线为绿光G沿主光轴方向的光线，虚线为绿光G沿最大发射半角θ方向的光线(为便于说明，仅选取一侧的光进行描述)。本实施例中，绿光G的主光轴垂直于液晶显示器件。
为避免像素串扰，要求避免绿光最外侧的最大发散半角的光照射到蓝像素或红像素。研究从第一微透镜阵列的入射面开始到液晶像素阵列的入射面的光路，为便于图示，设置了靠近第一微透镜阵列入射面的面 A为参考光波面，该参考光波面A与第一微透镜阵列的入射面无限接近(图中的距离为夸张的画法，仅为便于标记)，因此可以认为第一光束通过参考光波面A的截面积等于第一微透镜阵列的截面积，过参考光波面A的第一光束的发散半角θ等于第一微透镜阵列的入射光发散半角。为使各个微透镜单元的光路基本相同，整个第一微透镜阵列的尺寸与液晶像素阵列的尺寸相当，因此，发散半角θ也为，当第一光束的截面积与液晶显示器件的有效像素面积相当时的第一光束发散半角。
如图所示，单色液晶像素大小为x，第一微透镜阵列与液晶像素阵列的距离为L，微透镜单元30-1的折射率为n，则第一光束的发散半角θ满足以下关系：
Figure PCTCN2021116385-appb-000002
在本发明中，第一微透镜阵列与液晶像素阵列的距离L的设置受到多方面因素的影响。一方面，距离L与第一微透镜阵列的微透镜单元的焦距直接相关，过小的焦距导致微透镜单元的曲率半径增大、成本增加、球差增加；另一方面，受光学元件装配精度的影响，L越小，装配误差带来的影响越大；此外，还有发热的液晶像素阵列对第一微透镜阵列的传热造成的热失真影响，L越小，传热越明显。液晶像素的尺寸x则受到自身成本、下游光路的投影镜头成本等的影响，不能采用过大尺寸。因此，综合多方面因素，在当第一光束的截面积与液晶显示器件的有效像素面积相当时，本发明的第一光束发散半角θ不大于6°。
请参见图6，为另一微透镜至液晶像素的光路示意图，该图仅选取红光R为分析光线，绿光的路径及图中标记编号可参考图5。由于上游光路的波长角度分光器的作用，红光R与绿光G的主光轴之间存在夹角，红光R以整体斜入射的方式入射到第一微透镜阵列，并在微透镜单元的汇聚作用下，汇聚到红绿蓝像素组的红像素区域。同样地，实线为红光R沿主光轴方向的光线，虚线为红光R沿最大发射半角方向的光线(为便于说明，同样仅选取一侧的光进行描述)。在仅考虑红光铺满红像素的极限情况，使得不发生像素串扰，则图6所示的红光情形与图5所示的绿光情形类似，因此，第一光束的红光发散半角θ也满足不大于6°或者满足条件：
Figure PCTCN2021116385-appb-000003
值得注意的是，在第一光束被第一波长角度分光器分成彩色光束之前，红光成分、绿光成分和蓝光成分处于重合状态，各自的光束截面积与光束发散角相同。在第一光束成为彩色光束之后，各光束在主光轴传播角度上发生变化，但是光束截面积仍可认为相同，因此，根据光学扩展量守恒，红光、绿光和蓝光的发散角也相同。所以，可以把红绿蓝单色光束的发散角等同于角度分光前的第一光束白光的发散角。
请继续参见图6，从包含红绿蓝液晶像素的彩色液晶像素组41-1的角度来看，该彩色像素的出射光中，角度最大的光来自从一个微透镜单元最边缘入射的最大发散半角红光，该红光在微透镜单元30-1的汇聚作用下，到达红液晶像素的最边缘(也即整个红绿蓝彩色像素的最边缘)，该光经红液晶像素调制后出射，成为液晶显示器件140的最大发射半角的出射光。为提高光利用率，投影镜头150对液晶显示器件140的出射光尽可能多的收集，因此要求投影镜头150的入镜头半角不小于液晶显示器件140的最大发射半角。一般地，镜头的收集角度越大，镜头的设计难度和成本越高。在本发明的光学架构中，镜头的收集角度需求与液晶像素尺寸x、第一微透镜阵列与液晶像素阵列的距离L、微透镜单元的折射率n相关，而x、L、n同时也与第一光束的发散半角θ相关，在研究了镜头实际产品化可行性的基础上，本发明优选地，当第一光束的截面积与液晶显示器件的有效像素面积相当时，第一光束的发散半角不大于3°。更进一步优选地，当第一光束的截面积与液晶显示器件的有效像素面积相当时，第一光束的发散半角不大于1.67°，具有更优异的经济性。
可以理解，在图5和图6的示例中，蓝光及蓝液晶像素与红光及红液晶像素位置对称，因此本发明仅以红光举例进行说明，蓝光的情形基本上参照红光，不再赘述。
以上，结合图3～图6对实施例一及本发明的通用技术特征进行了描述。在实施例一中，白光光源模块110包括沿光路方向一次设置的白光发光单元111、锥形反射器112、反射式偏振选择器件113和准直透镜114。其中，白光发光单元111可以为LED光源或激光荧光光源(即激 光激发荧光材料得到白光)。更普遍的，在本发明中，白光光源模块可以至少包括LED光源和角分布转换器，LED光源发出的光经角分布转换器转换后，得到第一光束。
角分布转换器利用光学扩展量守恒的原理，使得出射光束的截面积大于入射光束的截面积，从而减小光束的发散角。LED光源本身的发散角较大，无法直接出射可用的第一光束，因此需要配合角分布转换器得到第一光束。实施例一中的锥形反射器112和准直透镜114就可以看作一种角分布转换器。
在本发明的其他实施方式中，白光光源模块还可至少包括激光荧光光源和角分布转换器，激光荧光光源发出的光经角分布转换器转换后，得到第一光束。请参见图7，为本发明实施例一的变形实施例的结构示意图。单板式液晶投影装置100’包括白光光源模块110’、第一波长角度分光器120、第一微透镜阵列130、液晶显示器件140和投影镜头150。图7所示变形实施例中，编号与图3相同的部分，参照实施例一中的描述。本实施例与实施例一的区别在于，本实施例中，白光光源模块110’包括激光荧光光源和角分布转换器。其中，激光荧光光源包括激发光源115和波长转换装置116；角分布转换器包括锥形反射器112’，锥形反射器112’上包括一入光口，激发光源115发出的激发光经入光口入射进入锥形反射器112’，而后到达波长转换装置116。在一个具体实施方式中，激发光源115为蓝光激光器(如蓝光激光二极管或蓝光激光二极管阵列)，波长转换装置116包括黄色荧光材料，蓝光激光激发黄色荧光材料产生黄光与未被吸收的蓝光，从而形成白光出射光。该白光的发散角较大，因此通过锥形反射器112’的作用得到大光束截面积小光发散角的光束。波长转换装置116可以包括荧光玻璃层、荧光陶瓷层或有机荧光层。相对于实施例一的技术方案，本变形实施例进行了光源的替换，具有更高的发光效率，适用于更高亮度的应用场景。
图7所述的变形实施例中，波长转换装置116为反射式波长转换装置，即激发光的入射侧与荧光的出射侧在波长转换装置116的同侧，在本发明的其他实施方式中，波长转换装置也可以为透射式波长转换装置，激发光源设置于波长转换装置的远离角分布转换器的一侧。
在本发明的其他实施方式中，白光光源模块还可以包括半导体固态光源阵列和光整形装置，半导体固态光源阵列发出的光经光整形装置整形后，得到第一光束。请参见图8，为本发明实施例一的又一变形实施例的结构示意图。单板式液晶投影装置100”包括白光光源模块110”、第一波长角度分光器120、第一微透镜阵列130、液晶显示器件140和投影镜头150。图8所示变形实施例中，编号与图3相同的部分，参照实施例一中的描述。
本变形实施例中，白光光源模块110”包括固态光源阵列117、光整形装置118和偏振转换器113’，具体地，固态光源阵列117包括红激光二极管阵列、绿激光二极管阵列和蓝激光二极管阵列，三者通过光整形装置118合光并匀光。光整形装置118例如可以为一积分棒。光整形装置118的出射光经偏振转换器113’作用，得到以单一偏振态出射的第一光束。偏振转换器113’可以为一PCS阵列，其可应用到各实施例中，对反射式偏振选择器件113进行替换，但会造成光学扩展量的稀释。
在图8所示的变形实施例中，固态光源阵列也可以替换为LED光源阵列，由于其发散角较大，因此还是需要角分布转换器将其转为小发散角的光，以便于后续光路。
在图8中，RGB三色固态光源直接通过积分棒进行耦合。在本发明其他实施方式中，也可以通过二向色片先将RGB三色光合光，然后再进行整形和/或角分布转换。
在本发明的一个实施方式中，还可以采用固态光源与透明荧光棒结合的方式获得第一光束，其中，固态光源发出激发光入射到透明荧光棒内，一部分直接通过透明荧光棒在出射面出射，一部分激发透明荧光棒后，形成与激发光互补的荧光，而后在出射面出射。透明荧光棒可做成角分布转换器的形状。
请参见图9，为本发明实施例一的又一变形实施例的结构示意图。单板式液晶投影装置100”’包括白光光源模块110”’、第一波长角度分光器120、第一微透镜阵列130、液晶显示器件140和投影镜头150。图9所示变形实施例中，编号与图3相同的部分，参照实施例一中的描述。本实施例中，白光光源模块110”’包括固态光源阵列117’和光整形装置 119，其中，固态光源阵列117’同向设置，为激光二极管阵列，通过包括复眼透镜对的光整形装置119进行匀光以及改变发散角。
在本发明中，当采用激光直接作为白光光源模块的发光源时，由于激光的光学扩展量小、能量密度高，往往需要对激光进行扩束与准直。激光的光学扩展量越小，激光出射口的光发散角越小，则激光器的成本越高，因此，为提高本发明的产品化经济性，优选地，当第一光束的截面积与液晶显示器件的有效像素面积相当时，第一光束的发散半角不小于0.014°。
请参见图10，为本发明单板式液晶投影装置的实施例二的结构示意图。单板式液晶投影装置200包括白光光源模块210、第一波长角度分光器220、第一微透镜阵列230、液晶显示器件240、投影镜头250和第二波长角度分光器260。
白光光源模块210、第一波长角度分光器220、第一微透镜阵列230、液晶显示器件240、投影镜头250，可参照上述实施例中的白光光源模块110/110’/110”/110”’、第一波长角度分光器120、第一微透镜阵列130、液晶显示器件140、投影镜头150的描述，此处不在赘述。与实施例一相比，实施例二的主要区别在于增加了第二波长角度分光器260。由于第一波长角度分光器220使得第一光束的蓝光成分和红光成分分别相对绿光成分的主光轴向两侧偏移了一定角度，导致不利于光收集。为解决这个问题，设置第二波长角度分光器260对两侧的光进行拉直，使得红光、绿光和蓝光成分的主光轴能够尽可能保持平行。
在本实施例中，第二波长角度分光器260设置于液晶显示器件240与投影镜头250之间，用于使彩色图像的各色光束的主光轴平行。
在本实施例二的变形实施例中，第二波长角度分光器还可以设置于第一微透镜阵列与液晶显示器件之间，用于使彩色光束成为红绿蓝分离且各光束的主光轴平行的彩色光束阵列。在该实施方式中，由于已通过第一微透镜阵列完成了对面分布到角分布的转化，不会使得已经分离的红绿蓝光束重新合并为白光光束。该实施方式只旨在于改变红光和蓝光的主光轴方向。需要说明的是，该技术方案的难度较高，由于原本第一微透镜阵列到达液晶像素阵列的距离一般在1mm以内，而且该距离越 近，越有利于避免微透镜单元之间的接缝产生的杂散光的影响，因此难以再进一步在该空间内设置其他光学元件，也难以保证安装精度；而且波长角度分光器具有一定的折射率，导致对光程的计算复杂化；除此之外，第二波长角度分光器与第一微透镜阵列的对位也存在难度。因此，本发明优选地是采用如图10所示的将第二波长角度分光器260设置于液晶显示器件240之后的方案。
在本实施例二或其变形实施例中，第二波长角度分光器为衍射光学器件，如衍射光栅、二元光学元件、以及其他可以实现衍射作用的微光学结构；第二波长角度分光器还可以为第二微透镜阵列；第二波长角度分光器还可以为色散元件，如棱镜或者包含棱镜结构的器件，例如，当第一波长角度分光器为色散元件时，第二波长角度分光器为反向设置的色散元件，两者呈垂直翻转布置，使得每一光束等效于穿过平行六面体，从而光束的主光轴方向保持一致。
请参见图11，为实施例二的变形实施例中，第一微透镜阵列230至第二波长角度分光器260’的光路结构示意图，其中，第二波长角度分光器260’为第二微透镜阵列，该第二微透镜阵列260’与液晶显示器件240的液晶像素阵列相对应，第二微透镜阵列260’的每三个微透镜单元对应第一微透镜阵列230的一个微透镜单元。当第一微透镜阵列230为一维分布的柱透镜阵列时，第二微透镜阵列260’也是一维分布的柱透镜阵列，第二微透镜阵列260’的每一柱透镜对应一行或一列液晶像素；当第一微透镜阵列230为二维分布的柱透镜阵列时，第二微透镜阵列260’也是二维分布的柱透镜阵列，第二微透镜阵列260’的每一柱透镜对应一个液晶像素。
图11仅示出了平行于主光轴入射到第一微透镜阵列230的红绿蓝主波长光束，因此，在第一微透镜阵列230的作用下，红绿蓝主波长光束分别汇聚到液晶显示器件240的红绿蓝液晶像素的一点；以相对于主光轴方向偏移一定角度的发散光则汇聚到第一微透镜阵列230的焦平面的其他点，从而填充红绿蓝液晶像素。对于位于彩色像素组中间的绿液晶像素，其入射光为垂直入射的绿光，出射后，绿光主光轴不变，对应的第二微透镜阵列260’的微透镜单元对其进行准直，将液晶显示器件 240的液晶像素阵列设置在第二微透镜阵列260’的前焦面上，则严格沿主光轴方向的绿光在第一微透镜阵列230之前和第二微透镜阵列260’之后都是绝对的平行光。考虑到实际情况中不存在绝对的平行光，入射到第一微透镜阵列230之前的光带有发散角，在第一微透镜阵列230至液晶显示器件240的过程中，光束铺满液晶像素，而非在液晶像素上聚焦为点/线，总体的单色光束截面积减小、发散角变大。
在由液晶显示器件240至第二微透镜阵列260’出射的过程中，光束截面积基本不变，光束的总体发散角不变，但是主光轴的方向被改变。这是由于，液晶像素阵列设置在第二微透镜阵列260’的前焦面，铺满液晶像素的光可看作无数零维发光点的累加，这些发光点发出的光经第二微透镜阵列260’作用被转化为绝对平行光，由无数零维点产生的无数绝对平行光的叠加，即为第二微透镜阵列260’的出射光。对于单个像素来说，不同位置的零维点产生的平行光的角度不同，也就构成了第二微透镜阵列260’的微透镜单元出射光的发散角。根据光学扩展量守恒，液晶显示器件240的液晶像素阵列的尺寸与第二微透镜阵列260’的尺寸相对应，因此两者的出射光发散角基本相等。
为使得第二微透镜阵列260’出射的红光的主光轴能够平行于绿光的主光轴，优选地，平行于红光主光轴的红光在红液晶像素上的焦点与红液晶像素对应的微透镜单元的中心的连线恰好平行于绿光主光轴。蓝光的情况与红光类似，将上述描述中的红光替换成蓝光即为蓝光的技术方案。
请参见图12，为本发明单板式液晶投影装置的实施例三的结构示意图。单板式液晶投影装置300包括白光光源模块310、第一波长角度分光器320、第一微透镜阵列330、液晶显示器件340、投影镜头350、第二波长角度分光器360和像素偏移装置370。其中，白光光源模块310、第一波长角度分光器320、第一微透镜阵列330、液晶显示器件340、投影镜头350、第二波长角度分光器360的描述可以参照上述各实施例及其变形实施例的描述。
与上述实施例相比，本实施例三的区别主要在于，增加了像素偏移装置370，设置于液晶显示器件340的出射光路上，用于使彩色图像的 光束沿垂直于光轴的方向平移，使得不同平移位置的彩色图像时序叠加。
像素偏移装置370可以是通过电流或电压控制转动角度的透明平板光学器件，当像素偏移装置370的透明平板转动一定角度时，通过该透明平板的光经过两次折射后而整体平移，透明平板在转动位置处停留预定时间，然后转动到其他位置。在一个图像帧周期中，像素偏移装置370可以包括2个稳态或4个稳态，图像被响应的拆成2个子帧或4个子帧，人眼通过时间积分功能，对捕获的2个或4个图像进行叠加，从而在脑中形成高分辨率的图像。可以理解，像素偏移装置还可以包括更多的稳态，从而实现更高的分辨率，本发明不对像素的倍增数量做限制。
在其他实施方式中，像素偏移装置还可以是液晶双折射装置，通过电压控制液晶分子的偏转角度，从而对通过该液晶双折射装置的光进行平移，从而实现整体像素偏移的作用，效果类似于上述机械转动的像素偏移装置，此处不再赘述。
在本发明的实施例四中，以上述各实施例或其变形实施例为基础，还包括设置于光路中的滤光单元，该滤光单元用于减少光路中的绿光主波长与红光主波长之间的光成分及/或滤光单元用于减少光路中的蓝光主波长与绿光主波长之间的光成分。
该滤光单元可以为一个整块的滤光片，可以设置在光路的多种位置。例如可以设置在白光光源模块内，直接从源头对白光进行修色，也可以设置在白光光源模块与第一波长角度分光器之间、第一波长角度分光器与第一微透镜阵列之间、第一微透镜阵列与液晶显示器件之间、液晶显示器件与投影镜头之间。通过设置滤光单元，能够对红绿蓝色的色坐标进行调节，使得图像颜色更鲜艳，色域更广。将滤光片设置于液晶显示器件的上游光路中，能够减少光穿过液晶显示器件时产生的热量。
滤光单元还可以为与液晶像素一一对应的滤光阵列，对红绿蓝像素出射的红绿蓝光分别进行滤光修色，从而达到更精细的光谱效果。该滤光阵列可以通过阵列化镀膜实现，滤光膜层可以是吸收型的或反射型的。
请参见图13，为滤光后的光谱曲线，对红光与绿光、绿光与蓝光之间的混合色光成分进行滤除，从而提高色域。可以理解，当采用的光源为窄光谱光源，如纯激光光源时，红光、绿光、蓝光的光谱彼此为分离 的光谱，那么则可以不设置滤光单元。
在本发明的实施例五中，以上述各实施例或其变形实施例为基础，还包括吸收栅格，设置在第一微透镜阵列与液晶显示器件之间。请参见图14为本发明单板式液晶投影装置实施例五的第一微透镜阵列到液晶像素阵列的局部光路结构示意图。来自第一微透镜阵列30光在到达液晶像素阵列41之前，部分被吸收栅格43吸收。吸收栅格包括阵列式的吸收区与透光区，图中的黑色部分即为吸收区，吸收区设置于彩色光束的绿光主波长光束与红光主波长光束之间及/或设置于彩色光束的蓝光主波长光束与红光主波长光束之间。为便于说明，本实施例附图13仅示出了绿光主波长光束，以及绿光主波长光束与红光主波长光束之间的黄光Y的部分光束。由于黄光Y的波长介于绿光与红光之间，因此在通过第一波长角度分光器后，黄光相对于绿光的角度偏移量小于红光相对于绿光的角度偏移量，因此黄光Y的传播路径介于绿光与红光之间。通过各波长光束在空间位置上的差异，对应的设置吸收栅格，能够无需复杂的镀膜工艺制造滤光膜，具有成本优势。而且，通过设置吸收栅格，能够进一步消除可能存在的串扰光，进一步减少像素串扰。
在本实施例中，吸收栅格43设置于液晶显示器件上，可以同时作为液晶显示器件的电路导线，恰好对应到液晶像素单元的控制电路，从而一举两得。可以理解，在本发明的其他实施方式中，也可以使吸收栅格相对于液晶像素阵列悬空设置，从而使得吸收栅格吸收光束而产生的热量不会直接传导到液晶像素阵列上，提高其可靠性。
吸收栅格43所吸收的光谱可以参照图13上述的情况，通过吸收栅格43对光进行吸收，能够做到在该区域完全吸收，不存在透射率曲线随角度变化的问题，更加可靠。
在本发明的实施例六中，为解决彩色像素分离的问题，同时提高彩色像素分辨率，第一波长角度分光器包括至少三个分区及一个驱动装置，在驱动装置的驱动下，各个分区分时的位于白光光源模块出射的第一光束的光路上，以使第一波长角度分光器分时的出射红绿蓝排列方式不同的彩色光束。
举例说明，上述各实施例中，第一波长角度分光器的出射光的角度 按照图中从左到右的蓝、绿、红的排序，绿光位于中央，实现该排列的第一波长角度分光器可作为实施例六的第一波长角度分光器的第一分区；在实施例六的第一波长角度分光器的第二分区，出射光的角度按照红、蓝、绿的排序，在实施例六的第一波长角度分光器的第三分区，出射光的角度按照绿、红、蓝的排序。第一分区、第二分区、第三分区按照顺序周期性的位于光路中，从而得到红绿蓝光轮循的出射光。该技术方案使得每一个液晶像素都能够在一个图像帧内在不同时序分别出射红绿蓝光，使得该像素成为包含红绿蓝全色的彩色像素。在同样的液晶像素数量的情况下，图像像素数量增加为原来的三倍。
可以理解，虽然在实施例六中列举了三个分区的情况，在本发明的其他实施方式中，也可以有三个以上数量的分区，不对此做出限制。在该类实施例中，由于液晶像素并非对应某一特定颜色，因此不宜在液晶像素后方设置阵列化的滤光膜层阵列。
在本发明的实施例七中，以上述各实施例或其变形实施例为基础，还包括位于液晶显示器件出射侧的混光装置。请参见图15，为本发明的单板式液晶投影装置实施例七的局部光路结构示意图。液晶显示器件740包括液晶像素阵列741和混光装置744，其中液晶像素阵列包括多个彩色液晶像素，彩色液晶像素定义为每一彩色液晶像素至少包括三个液晶像素，混光装置744包括多个混光单元，混光单元与彩色液晶像素一一对应，使得混光装置用于将每一彩色液晶像素的出射光混合均匀。
具体地，在本实施例七中，混光装置744包括混光腔7441以及散射单元7442，混光腔7441用于使彩色液晶像素的出射光限制在混光腔内传播，然后通过散射单元7442出射，从而达到匀光整形的效果，使得每个彩色液晶像素的出射光都是包括红光、绿光和蓝光成分的彩色光，可以直接作为一个彩色像素使用。
在实施例七的技术方案中，由于至少三个液晶像素构成一个彩色液晶像素，使得该技术方案的图像的分辨率不高。为进一步提高分辨率，在实施例七的变形实施例中，可进一步增加像素偏移装置，设置于液晶显示器件的出射光路上，用于使液晶显示器件出射的彩色图像的光束沿垂直于光轴的方向平移，使得不同平移位置的的彩色图像时序叠加。
请参见图16，为像素偏移后的图像时序叠加示意图。设一个图像帧包括两个图像子帧，在一个图像帧周期T内，分别在第一图像帧周期T 1和第二图像帧周期T 2显示图中虚线和实线两组子帧图像，两者叠加，形成分辨率更高的图像。在本实施例中，列举了像素偏移装置的一种技术方案，更多技术方案可以参考图12的实施例三及其变形实施例的描述，此处不再赘述。
本说明书中各个实施例采用递进的方式描述，每个实施例重点说明的都是与其他实施例的不同之处，各个实施例之间相同相似部分互相参见即可。
以上所述仅为本发明的实施方式，并非因此限制本发明的专利范围，凡是利用本发明说明书及附图内容所作的等效结构或等效流程变换，或直接或间接运用在其他相关的技术领域，均同理包括在本发明的专利保护范围内。

Claims (20)

  1. 一种单板式液晶投影装置，其特征在于，包括
    白光光源模块，用于发出第一光束，所述第一光束至少包括红光、绿光和蓝光成分；
    第一波长角度分光器，用于使不同波长的光沿不同角度出射，所述第一光束经所述第一波长角度分光器成为彩色光束；
    第一微透镜阵列，由多个微透镜单元组成，设置于所述波长角度分光器的出射光光路上，用于将所述彩色光束汇聚，使得所述彩色光束在参考平面上形成红绿蓝分离的彩色条纹或彩色斑点；
    液晶显示器件，包括包含多个液晶像素的液晶像素阵列，所述液晶像素阵列设置于所述参考平面上，不同颜色的所述彩色条纹或彩色斑点分别落入不同的液晶像素上，所述液晶显示器件用于对入射光进行调制，形成彩色图像出射；
    投影镜头，用于将所述液晶显示器件出射的彩色图像投射至预定位置；
    其中，当所述第一光束的截面积与所述液晶显示器件的有效像素面积相当时，所述第一光束的发散半角不大于6°。
  2. 根据权利要求1所述的单板式液晶投影装置，其特征在于，当所述第一光束的截面积与所述液晶显示器件的有效像素面积相当时，所述第一光束的发散半角不大于3°。
  3. 根据权利要求1所述的单板式液晶投影装置，其特征在于，当所述第一光束的截面积与所述液晶显示器件的有效像素面积相当时，所述第一光束的发散半角不大于1.67°。
  4. 根据权利要求1所述的单板式液晶投影装置，其特征在于，当所述第一光束的截面积与所述液晶显示器件的有效像素面积相当时，所述第一光束的发散半角不小于0.014°。
  5. 一种单板式液晶投影装置，其特征在于，包括
    白光光源模块，用于发出第一光束，所述第一光束至少包括红光、绿光和蓝光成分；
    第一波长角度分光器，用于将所述第一光束分为不同波长沿不同角度传播的彩色光束；
    第一微透镜阵列，由多个微透镜单元组成，设置于所述波长角度分光器的出射光光路上，用于将所述彩色光束汇聚，使得所述彩色光束在参考平面上形成红绿蓝分离的彩色条纹或彩色斑点；
    液晶显示器件，包括包含多个液晶像素的液晶像素阵列，所述液晶像素阵列设置于所述参考平面上，不同颜色的所述彩色条纹或彩色斑点分别落入不同的液晶像素上，所述液晶显示器件用于对入射光进行调制，形成彩色图像出射；
    投影镜头，用于将所述液晶显示器件出射的彩色图像投射至预定位置；
    其中，当所述第一光束的截面积与所述液晶显示器件的有效像素面积相当时，所述第一光束的发散半角θ满足以下关系：
    Figure PCTCN2021116385-appb-100001
    其中n为所述微透镜单元的折射率，x为所述液晶像素大小，L为所述第一微透镜阵列与所述液晶像素阵列的距离。
  6. 根据权利要求1至5中任一项所述的单板式液晶投影装置，其特征在于，所述白光光源模块至少包括LED光源和角分布转换器，所述LED光源发出的光经所述角分布转换器转换后，得到第一光束；
    或者，所述白光光源模块至少包括激光荧光光源和角分布转换器，所述激光荧光光源发出的光经所述角分布转换器转换后，得到第一光束；
    或者，所述白光光源模块包括半导体固态光源阵列和光整形装置，所述半导体固态光源阵列发出的光经所述光整形装置整形后，得到第一光束。
  7. 根据权利要求6所述的单板式液晶投影装置，其特征在于，所述白光光源模块还包括偏振转换器，用于使所述第一光束以单一偏振态出射。
  8. 根据权利要求1至5中任一项所述的单板式液晶投影装置，其特征在于，所述白光光源模块至少包括沿光路方向依次设置的白光发光单元、锥形反射器和反射式偏振选择器件，所述锥形反射器的面积较小的 一端为入射面，所述锥形反射器的面积较大的一端为出射面，所述白光发光单元出射的非偏振白光经所述锥形反射器的所述入射面入射，入射到所述锥形反射器内的光经所述锥形反射器的侧壁反射后由所述出射面出射或直接出射，所述锥形反射器的出射光中，至少部分透射所述反射式偏振选择器件后以单一偏振态出射，部分被所述反射式偏振选择器件反射后回到所述锥形反射器内。
  9. 根据权利要求1至5中任一项所述的单板式液晶投影装置，其特征在于，还包括第二波长角度分光器，所述第二波长角度分光器设置于所述第一微透镜阵列与所述液晶显示器件之间，用于使所述彩色光束成为红绿蓝分离且各光束的主光轴平行的彩色光束阵列；
    或者，所述第二波长角度分光器设置于所述液晶显示器件与所述投影镜头之间，用于使所述彩色图像的各色光束的主光轴平行。
  10. 根据权利要求9所述的单板式液晶投影装置，其特征在于，所述第二波长角度分光器为衍射光学器件、第二微透镜阵列或色散元件。
  11. 根据权利要求9所述的单板式液晶投影装置，其特征在于，所述第二波长角度分光器为第二微透镜阵列，所述第二微透镜阵列的每三个微透镜单元对应所述第一微透镜阵列的一个微透镜单元。
  12. 根据权利要求1至5中任一项所述的单板式液晶投影装置，其特征在于，还包括像素偏移装置，设置于所述液晶显示器件的出射光路上，用于使所述彩色图像的光束沿垂直于光轴的方向平移，使得不同平移位置的彩色图像时序叠加。
  13. 根据权利要求1至5中任一项所述的单板式液晶投影装置，其特征在于，还包括设置于光路中的滤光单元，所述滤光单元用于减少光路中的绿光主波长与红光主波长之间的光成分及/或所述滤光单元用于减少光路中的蓝光主波长与绿光主波长之间的光成分。
  14. 根据权利要求1至5中任一项所述的单板式液晶投影装置，其特征在于，还包括吸收栅格，设置于所述第一微透镜阵列与所述液晶显示器件之间，所述吸收栅格包括阵列式的吸收区与透光区，所述吸收区设置于所述彩色光束的绿光主波长光束与红光主波长光束之间及/或所述吸收区设置于所述彩色光束的蓝光主波长光束与红光主波长光束之 间。
  15. 根据权利要求14所述的单板式液晶投影装置，其特征在于，所述吸收栅格设置于所述液晶显示器件上，同时用作所述液晶显示器件的电路导线。
  16. 根据权利要求1至5中任一项所述的单板式液晶投影装置，其特征在于，所述液晶显示器件包括检偏器，所述检偏器与所述液晶像素阵列分离设置。
  17. 根据权利要求1至5中任一项所述的单板式液晶投影装置，其特征在于，所述第一微透镜阵列为一维分布的柱透镜阵列，每一所述柱透镜对应三行或三列所述液晶像素；或者
    所述第一微透镜阵列为二维分布的柱透镜阵列，每一所述柱透镜对应三个液晶像素。
  18. 根据权利要求1至5中任一项所述的单板式液晶投影装置，其特征在于，所述液晶像素阵列包括多个彩色液晶像素，每一所述彩色液晶像素至少包括三个液晶像素，所述液晶显示器件还包括位于其出射侧的混光装置，所述混光装置用于将每一所述彩色液晶像素的出射光混合均匀。
  19. 根据权利要求18所述的单板式液晶投影装置，其特征在于，还包括像素偏移装置，设置于所述液晶显示器件的出射光路上，用于使所述彩色图像的光束沿垂直于光轴的方向平移，使得不同平移位置的彩色图像时序叠加。
  20. 根据权利要求1至5中任一项所述的单板式液晶投影装置，其特征在于，所述第一波长角度分光器包括至少三个分区及一个驱动装置，在所述驱动装置的驱动下，各所述分区分时的位于所述第一光束的光路上，以使所述第一波长角度分光器分时的出射红绿蓝排列方式不同的彩色光束。
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