CN113589629A

CN113589629A - Projection display device and calibration method thereof

Info

Publication number: CN113589629A
Application number: CN202110420836.7A
Authority: CN
Inventors: 杨乐宝; 谢振霖
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2020-04-30
Filing date: 2021-04-19
Publication date: 2021-11-02
Anticipated expiration: 2041-04-19
Also published as: CN113589629B

Abstract

The present disclosure relates to projection display technologies, and particularly to a projection display device and a calibration method thereof. The projection display device comprises a light emitting module and a modulation module, wherein the light emitting module sequentially comprises a light source for emitting linearly polarized light, a diffusion sheet and a collimating lens along a light path, a modulation component of the modulation module comprises a light combining prism and an LCOS modulator, and the LCOS modulator is used for generating modulated light and non-modulated light; the diffusion sheet comprises a substrate layer, a first transmission surface, a reflection surface and a second transmission surface, wherein the first transmission surface is arranged on one side of the substrate layer, and the reflection surface and the second transmission surface are arranged on the other side of the substrate layer; at least part of the non-modulated light energy is incident to the reflecting surface after sequentially passing through the light-combining prism, the light-homogenizing assembly and the collimating lens. At least part non-modulation light can be incited to the plane of reflection after following beam combining prism, dodging subassembly and collimating lens in proper order in this application, and the plane of reflection incides this part light modulation module again and is recycled to can improve projection display device's average light efficiency.

Description

Projection display device and calibration method thereof

The present application claims priority from the chinese patent application entitled "projection display device and method for calibrating the same" filed by the chinese patent office on 30/04/2020, application number 202010367307.0, the entire contents of which are incorporated herein by reference.

Technical Field

The present disclosure relates to projection display technologies, and particularly to a projection display device and a calibration method thereof.

Background

The conventional projection display device generally includes a light emitting module, a modulation module and a lens module, which are connected in sequence, and light emitted by the light emitting module is modulated by the modulation module and then projected by the lens module to a specific position (for example, a screen) to display an image.

However, the existing modulating module based on an LCOS (Liquid crystal on Silicon, or reflective Liquid crystal light valve) modulator usually adopts one or three pieces (i.e. one LCOS modulator or three LCOS modulators are adopted), wherein the three pieces of modulating module are different from the one piece of modulating module in that: the former can further increase the display luminance and image quality of the projection screen of the projection display device. Taking the three-chip modulation module as an example, for a general projection picture, since all the projection pictures are not full white pictures (here, the full white pictures are named from the perspective of gray scale, that is, the full white pictures can be regarded as pictures with the maximum gray scale value, that is, the brightest pictures), a part of light is always lost because the LCOS modulator is not modulated.

Therefore, a projection display device and a calibration method thereof are needed to solve the above problems.

Disclosure of Invention

The application provides a projection display device and a calibration method thereof, which are used for reducing the light loss of the projection display device, thereby improving the average light efficiency of the projection display device.

In a first aspect, an embodiment of the present application provides a projection display device, including:

the light emitting module comprises a light source for emitting linearly polarized light, a diffusion sheet and a collimating lens in sequence along a light path;

the modulating module sequentially comprises a light homogenizing assembly and a modulating assembly along a light path, the light homogenizing assembly is arranged on the light emitting side of the collimating lens, the modulating assembly comprises a light combining prism and an LCOS modulator, and the LCOS modulator is used for generating modulated light and non-modulated light;

the diffusion sheet comprises a substrate layer, a first transmission surface, a reflection surface and a second transmission surface, the first transmission surface is arranged on one side of the substrate layer, the reflection surface and the second transmission surface are arranged on the other side of the substrate layer, and the second transmission surface is arranged inside the reflection surface;

at least part of the non-modulated light energy enters the reflecting surface after sequentially passing through the light-combining prism, the light-homogenizing assembly and the collimating lens.

In one possible design, the diffuser and the collimating lens are arranged eccentrically.

In one possible design, the first transmission surface and the second transmission surface have particles made of resin and an adhesive for fixing the particles.

In one possible design, the dodging assembly includes a fly-eye lens array and a focusing lens.

In one possible design, the light source includes a red laser light source, a green laser light source and a blue laser light source, a beam combining assembly for combining red light, green light and blue light is arranged on the light emitting side of the light source, and the diffusion sheet is arranged on the light emitting side of the beam combining assembly.

In a possible design, even light subassembly includes fly eye lens array and focusing lens along the light path in proper order, fly eye lens array set up in collimating lens's light-emitting side, the modulation subassembly set up in focusing lens's light-emitting side.

In one possible design, the light combining prism comprises four right-angle prisms, and the light combining prism has four side surfaces and four intersecting surfaces formed by the four right-angle prisms;

the LCOS modulator comprises a first LCOS modulator, a second LCOS modulator and a third LCOS modulator, and the first LCOS modulator, the second LCOS modulator and the third LCOS modulator are respectively arranged on the light emergent sides of the three different side surfaces;

after light enters the light-combining prism, light splitting can be realized through two intersecting surfaces, and light combining can be realized through one of the other two intersecting surfaces.

In one possible design, one monochromatic light of the red light, the green light and the blue light emitted by the light source is in a first linear polarization state, the other two monochromatic lights are in a second linear polarization state, and the first linear polarization state is different from the second linear polarization state.

In one possible design, two of the intersecting surfaces are polarization splitting surfaces, and the other two intersecting surfaces are dichroic surfaces, and the polarization splitting surfaces and the dichroic surfaces are distributed in a staggered manner.

In one possible design, the polarization splitting plane, which is capable of splitting two monochromatic lights of different linear polarization states, is provided with a metal wire grid.

In one possible design, both of the polarization splitting planes are provided with a metal wire grid.

In a second aspect, an embodiment of the present application provides a calibration method for a projection display apparatus, including:

projecting a pure color picture, changing parameters of a light source, measuring projection brightness corresponding to different parameters of the light source, normalizing the parameters of the light source and the projection brightness, and obtaining a first comparison table of the normalized parameters of the light source and the projection brightness;

controlling the parameters of the light source to be unchanged, inputting pictures exceeding a preset value into the projection display device, measuring the sum of gray values in each picture and the projection brightness corresponding to each picture, and normalizing the sum of gray values in each picture and the projection brightness to obtain a second comparison table of the sum of gray values and the projection brightness in each picture after normalization;

obtaining a third comparison table of the normalized parameters of the light source and the sum of the gray values in each picture through the first comparison table and the second comparison table;

and writing a program corresponding to the third comparison table into the projection display device.

In one possible design, the light sources include a red laser light source, a green laser light source, and a blue laser light source.

In one possible design, the parameter of the light source comprises a current value or a duty cycle.

It is thus clear that, the reflection plane of diffusion piece is incided to at least some non-modulation light ability in this application after following beam combination prism, dodging subassembly and collimating lens in proper order, and the reflection plane incides this part light again in the modulation module and is recycled to reduce projection display device's light loss, thereby can improve projection display device's average light efficiency.

Drawings

Fig. 1 is a schematic diagram of a projection display device according to an embodiment of the present application;

FIG. 2 is a schematic diagram of a projection display apparatus according to another embodiment of the present disclosure;

FIG. 3 is a top view of a diffuser plate in the projection display device shown in FIG. 1 or FIG. 2;

FIG. 4 is a schematic cross-sectional view of a diffuser plate in the projection display device shown in FIG. 1 or FIG. 2;

FIG. 5 is a schematic diagram of the optical path of the modulation assembly in the projection display device shown in FIG. 1 or FIG. 2;

fig. 6 is a schematic view of an application scenario of a projection display apparatus according to an embodiment of the present disclosure.

Reference numerals:

1-a light emitting module;

11-a light source;

111-red laser light source;

112-green laser light source;

113-blue laser light source;

114-a first dichroic mirror;

115-a second dichroic mirror;

116-a third dichroic mirror;

12-a first focusing lens;

13-a diffusion sheet;

131-a substrate layer;

132 — a first transmissive surface;

133-a reflective surface;

134-a second transmissive surface;

14-a collimating lens;

2-a modulation module;

21-a light homogenizing assembly;

211-a first fly-eye lens array;

212-a second fly-eye lens array;

213-a second focusing lens;

214-a third focusing lens;

22-a modulation component;

221-a light-combining prism;

221 a-first high-transmittance surface;

221 b-a second high-transmittance surface;

221 c-third high-transparency surface;

221 d-fourth high-transmittance surface;

221 e-first intersecting plane;

221 f-second intersecting surface;

221 g-third intersecting plane;

221 h-fourth intersecting surface;

222-a metal wire grid;

223-a first LCOS modulator;

224-a second LCOS modulator;

225-third LCOS modulator;

3-lens module.

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and together with the description, serve to explain the principles of the application.

Detailed Description

The present application will be described in detail below with reference to the drawings and examples. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.

In the description of the embodiments of the present application, the terms "first", "second", and the like, unless expressly specified or limited otherwise, are used for descriptive purposes only and are not to be construed as indicating or implying relative importance; the term "plurality" means two or more unless specified or indicated otherwise; the terms "connected," "fixed," and the like are to be construed broadly and may, for example, be fixedly connected, detachably connected, integrally connected, or electrically connected; may be directly connected or indirectly connected through an intermediate. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as appropriate.

In the description of the present application, it should be understood that the terms "upper" and "lower" used in the description of the embodiments of the present application are used in a descriptive sense only and not for purposes of limitation. In addition, in this context, it will also be understood that when an element is referred to as being "on" or "under" another element, it can be directly on "or" under "the other element or be indirectly on" or "under" the other element via an intermediate element.

As shown in fig. 1, the projection display device includes a light emitting module 1, a modulation module 2, and a lens module 3, which are connected in sequence, wherein light emitted from the light emitting module 1 is modulated by the modulation module 2, and then projected by the lens module 3 to a specific position (e.g., a screen) to display an image.

The following describes each part of the projection display apparatus.

< light emitting Module 1>

The light emitting module 1 comprises a light source 11 for emitting polarized light. The light source 11 referred to in the present application includes both a case where the light source 11 is a light emitting element that directly emits polarized light (e.g., a semiconductor light emitting element array, a bulb light source, etc.), and a light emitting module 1 that is obtained by combining the light emitting element with another optical element and can emit polarized light (e.g., the light emitting module 1 in which the light emitting element is combined with a lens, and the light emitting module 1 in which the light emitting element is combined with a polarization conversion element). The light source described herein can be considered as a light-emitting "black box" that can contain any kind of optical element.

In the present embodiment, the light source 11 is a laser light source, such as a laser diode light source, a laser diode array light source, or a laser light source. The light source 11 has the characteristic of small optical expansion, so that the emitted polarized light has small light spots, small light divergence angles and small optical expansion when entering the modulation module 2, the phenomenon that a large amount of light cannot be utilized due to large divergence angles is avoided, and the light utilization rate is improved. If other light sources 11, such as a bulb light source and an LED light source, are used, the etendue thereof is much larger than that of a laser light source, so that the size of the incident surface of the light spot incident on the modulator device is satisfied, the divergence angle of the light will be enlarged, and a large amount of light cannot be utilized by the modulation module 2 and is absorbed and converted into heat outside the effective optical surface of the modulation module 2.

Of course, in an environment where the requirement for light utilization rate is not high, a bulb or an LED light source may be used as the light source 11 of the light emitting module 1.

In this embodiment, the light source 11 includes a red laser light source 111, a green laser light source 112, and a blue laser light source 113, and the light emitting module 1 further includes a beam combining component for combining the three laser light sources, where the beam combining component may be, for example, a combination of a dichroic mirror and a focusing lens, and may also be, for example, a combination of a dichroic mirror, a reflecting mirror, and a focusing lens. Illustratively, a red laser light source 111, a green laser light source 112, and a blue laser light source 113 are arranged in sequence, a first dichroic mirror 114 is disposed on a light emitting side of the red laser light source 111, and the first dichroic mirror 114 is configured to transmit red light and reflect blue light and green light; a second dichroic mirror 115 is arranged on the light emitting side of the green laser light source 112, and the second dichroic mirror 115 is used for transmitting blue light and reflecting green light; the light exit side of the blue laser light source 113 is provided with a third dichroic mirror 116, and the third dichroic mirror 116 is used for reflecting blue light. In some implementations, the third dichroic mirror 116 may be replaced by a mirror. In order to combine the three laser light sources, the first dichroic mirror 114, the second dichroic mirror 115, and the third dichroic mirror 116 are arranged in parallel, and finally, the combined light is emitted from the first dichroic mirror 114 and then enters the first focusing lens 12.

In some embodiments, the light emitting module 1 further includes a diffusion sheet 13 and a collimating lens 14, the diffusion sheet 13 is used for eliminating laser speckle, the collimating lens 14 is used for enabling light to be parallel and uniform in a longer distance range, and light emitted from the first focusing lens 12 sequentially passes through the diffusion sheet 13 and the collimating lens 14 and is emitted and incident into the modulation module 2. In other embodiments, the diffuser 13 may be replaced by a diffuser wheel, which may be connected to a motor to control its rotation by the motor, i.e. the diffuser wheel reflects the light incident on the diffuser wheel uniformly by means of the rotation. The diffuser 13 and the diffuser wheel differ in that: the diffusion sheet 13 is fixed. The diffusion sheet 13 is more effective than the diffusion wheel 13 in eliminating laser speckle, but the diffusion wheel is more expensive to manufacture, so the diffusion sheet 13 or the diffusion wheel can be appropriately selected according to actual needs.

FIG. 3 is a top view of a diffuser plate in a projection display device; FIG. 4 is a schematic cross-sectional view of a diffuser plate in a projection display device. With reference to fig. 3 and 4, the diffusion sheet 13 provided in the embodiments of the present application includes a substrate layer 131, a first transmission surface 132, a reflection surface 133, and a second transmission surface 134, where the first transmission surface 132 is disposed on one side of the substrate layer 131, the reflection surface 133 and the second transmission surface 134 are disposed on the other side of the substrate layer 131, the second transmission surface 134 is disposed inside the reflection surface 133, for example, the second transmission surface 134 is located at a central position of the diffusion sheet 13, and the reflection surface 133 surrounds an outer periphery of the second transmission surface 134, so that light can exit from the second transmission surface 134. The light exits the first focusing lens 12 and enters the first transmission surface 132, and then enters the collimator lens 14 after passing through the base material layer 131 and the second transmission surface 134 in sequence.

After the light enters the modulation module 2 through the collimating lens 14, except for a full white frame (see description in the background art), a part of the light is modulated (which may be referred to as modulated light), and another part of the light is not modulated (which may be referred to as non-modulated light). The modulated light referred to in the present application is light corresponding to a display image of a projection display device, and is equivalent to light entering a display screen (or a lens module 3) in a general projection display device; the non-modulated light corresponds to light that can be recycled, and corresponds to light that is filtered out in a general projection display device and does not enter the display screen (or the lens module 3).

The unmodulated light returns along the original path of the optical path, when returning to the diffusion sheet 13, because the light spot focused by the collimating lens 14 (when returning, the focusing lens 14 performs the focusing function) is generally larger than the light spot focused by the first focusing lens 12, the light outside the second transmission surface 134 in the light spot is incident on the reflection surface 133, and the reflection surface 133 re-enters the light into the modulation module 2 and is reused, so that the average light efficiency of the projection display device can be improved.

The base material layer 131 may be formed of, for example, a colorless transparent synthetic resin, as necessary to transmit light. The synthetic resin used for the base layer 131 is not particularly limited, and may be, for example, polyethylene terephthalate, polyethylene naphthalate, an acrylic resin, polycarbonate, polystyrene, polyolefin, cellulose acetate, weather-resistant vinyl chloride, or the like. In some embodiments, a high transparency, high strength polyethylene terephthalate may be selected, and a polyethylene terephthalate with improved flexural properties may also be selected.

The first and second transmission surfaces 132 and 134 have fine particles and a binder for fixing the fine particles, which are relatively uniformly and densely laid on the surface of the base material layer 131, and the fine particles are covered with the binder. In this way, the first and second transmission surfaces 132 and 134 can uniformly diffuse light using the particles contained in the first and second transmission surfaces 132 and 134. Further, fine convex portions that are relatively uniform and dense can be formed on the surfaces of the first transmission surface 132 and the second transmission surface 134 by the fine particles, and the light can be diffused more favorably by the refraction action of the fine concave-convex lens formed on the surfaces of the first transmission surface 132 and the second transmission surface 134 in this manner.

In some implementations, the microparticles are substantially spherical transparent resin particles having light diffusing properties. Examples of the material for forming the fine particles include acrylic resin, acrylonitrile resin, urethane resin, vinyl chloride resin, styrene resin, polyamide, silicone resin, and fluororesin. Among them, acrylic resin having high transparency may be selected, and polymethyl methacrylate (PMMA) may be selected. The acrylic resin includes acrylic-styrene copolymer resin, acrylic-urethane copolymer resin, acrylic-fluorine copolymer resin, acrylic-silicone copolymer resin, and the like.

The adhesive may be formed by crosslinking and curing a polymer composition containing a base polymer. With this binder, the fine particles can be fixed to the surface of the base material layer 131 at relatively equal density. The polymer composition for forming the adhesive may be appropriately mixed with, for example, a fine inorganic filler, a curing agent, a plasticizer, a dispersant, various leveling agents, an ultraviolet absorber, an antioxidant, a viscosity modifier, a lubricant, a light stabilizer, and the like, in addition to the base polymer.

The base polymer is not particularly limited, and may be, for example, an acrylic resin, a urethane resin, a polyester resin, a fluororesin, a silicone resin, a polyamide-imide, an epoxy resin, an ultraviolet-curable resin, or the like, and at least one of these polymers may be used in combination. In some embodiments, as the base polymer, a polyol having high processability and easily forming the first and second transmission surfaces 132 and 134 by coating or the like may be selected. In addition, the base polymer used in the adhesive may be transparent as a whole, and may further be colorless and transparent from the viewpoint of improving light transmittance.

Fig. 2 is a schematic diagram of a projection display apparatus according to another embodiment of the present disclosure. The projection display device shown in fig. 2 is different from the projection display device shown in fig. 1 in that: the diffusion sheet 13 and the collimator lens 14 are eccentrically disposed. The arrangement is such that when the non-modulated light returns, an included angle is formed between the non-modulated light and the original incident light path; when the light enters the diffusion sheet 13 through the collimating lens 14, the light enters the diffusion sheet 13 at a position deviated from the center, that is, almost all the non-modulated light enters the reflection surface 133, and at this time, almost all the non-modulated light enters the modulation module 2 again and is reused, so that the average light efficiency of the projection display device can be further improved.

< modulation Module 2>

As shown in fig. 1 or fig. 2, the modulation module 2 includes a light uniformizing element 21 and a modulation element 22, the light uniformizing element 21 is disposed on the light emitting side of the light emitting module 1, and the modulation element 22 is disposed on the light emitting side of the light uniformizing element 21, specifically, the light uniformizing element 21 is disposed on the light emitting side of the collimating lens 14.

In some embodiments, the dodging assembly 21 includes a fly-eye lens array and a focusing lens, and the light emitted by the light emitting module 1 first passes through the fly-eye lens array and then through the focusing lens, so that the light is irradiated onto the LCOS modulator; and the utilization of fly-eye lens array and focusing lens can realize uniform illumination on LCOS modulator, and realize local dimming function. In other implementations, the fly-eye lens array may be replaced with an optical rod, which may be a solid optical rod or a hollow optical rod. In this embodiment, the fly-eye lens array includes two parallel rows of the first fly-eye lens array 211 and the second fly-eye lens array 212, and the focusing lens includes the second focusing lens 213 and the third focusing lens 214, so that uniform illumination can be achieved, and specific implementation principles are not described herein again.

As shown in fig. 5, which is a schematic diagram of the optical path of the modulating component. The modulation component 22 includes a light combining prism 221 and an LCOS modulator, the light combining prism 221 is composed of four right-angle prisms, the light combining prism 221 has four side surfaces and four intersecting surfaces formed by the four right-angle prisms, two adjacent sides of the four side surfaces are perpendicular to each other, and two adjacent sides of the four intersecting surfaces are perpendicular to each other. In this embodiment, the four side surfaces are the first high-transmittance surface 221a, the second high-transmittance surface 221b, the third high-transmittance surface 221c and the fourth high-transmittance surface 221d, respectively, so that the white light can be incident into the light-combining prism 221 or emergent from the light-combining prism 221 with high transmittance, and thus the utilization rate of the light can be improved; the four intersecting surfaces are respectively a first intersecting surface 221e, a second intersecting surface 221f, a third intersecting surface 221g and a fourth intersecting surface 221h, and the four intersecting surfaces have different optical characteristics, so that the light splitting and the light combining of the white light are realized. For example, it may be provided that the first intersecting surface 221e intersects with the first high-transmittance surface 221a and the second high-transmittance surface 221b, the second intersecting surface 221f intersects with the second high-transmittance surface 221b and the third high-transmittance surface 221c, the third intersecting surface 221g intersects with the third high-transmittance surface 221c and the fourth high-transmittance surface 221d, and the fourth intersecting surface 221h intersects with the fourth high-transmittance surface 221d and the first high-transmittance surface 221 a.

In the present embodiment, the number of the LCOS modulators is three, and the three LCOS modulators are respectively the first LCOS modulator 223, the second LCOS modulator 224, and the third LCOS modulator 225, and each LCOS modulator is respectively disposed on the light emitting side of three different sides of the light combining prism 221. After the light enters the light-combining prism 221, the light is split through two intersecting surfaces of the four intersecting surfaces, namely, the light is decomposed into red light, green light and blue light; the decomposed monochromatic light enters the LCOS modulators for modulation after passing through the side face arranged opposite to each LCOS modulator, the modulated monochromatic light enters the light combining prism 221 for light combination after passing through the side face arranged opposite to each LCOS modulator, and the light after light combination is emitted from one side face. The conventional LCOS modulator-based modulation module 2 generally adopts a plurality of polarization splitting prisms and a light combining prism 221 for combining beams, and the components for forming the mode are many and the structure is complex, so that the manufacturing cost of the projection display device is high. The modulation assembly 22 in the modulation module 2 of the present application only includes the light combining prism 221 and the LCOS modulator, i.e., omits a plurality of polarization splitting prisms, so that the parts of the modulation assembly 22 can be reduced, the structure is simple, and the manufacturing cost of the projection display device can be reduced.

In the present embodiment, the first LCOS modulator 223 is disposed on one side of the first high transmittance surface 221a, the second LCOS modulator 224 is disposed on one side of the second high transmittance surface 221b, and the third LCOS modulator 225 is disposed on one side of the third high transmittance surface 221 c; the light emitted from the light emitting module 11 is white light, one of the monochromatic light is in a first linear polarization state (for example, S state or P state), and the other two monochromatic light are in a second linear polarization state (for example, P state or S state), and the white light can be incident into the light combining prism 221 through the first high transparent surface 221a or the second high transparent surface 221b, and can be emitted from the light combining prism 221 through the third high transparent surface 221c or the fourth high transparent surface 221 d.

In one example, the first LCOS modulator 223 is used to modulate red light, the second LCOS modulator 224 is used to modulate blue light, and the third LCOS modulator 225 is used to modulate green light; the light emitted from the light emitting module 11 is white light, wherein the green light is P-state polarized light, and the red light and the blue light are S-state polarized light, and the white light is incident into the light combining prism 221 through the first high-transmittance surface 221a and is emitted from the light combining prism 221 through the fourth high-transmittance surface 221 d. In this example, the first intersecting surface 221e has optical characteristics that can be highly transmissive to blue-green light and highly reflective to red light, i.e., the first intersecting surface 221e is a dichroic surface; the second intersecting surface 221f has optical characteristics of transmitting P-state polarized light and reflecting S-state polarized light, that is, the second intersecting surface 221f is a polarization splitting surface; the third intersecting surface 221g has optical characteristics of high blue-green light transmittance and high red light reflectance, that is, the third intersecting surface 221g is a dichroic surface; the fourth intersecting surface 221h has optical characteristics of transmitting P-polarized light and reflecting S-polarized light, i.e., the fourth intersecting surface 221h is a polarization splitting surface. Namely, two of the intersecting surfaces are polarization splitting surfaces, the other two intersecting surfaces are dichroic surfaces, and the polarization splitting surfaces and the dichroic surfaces are distributed in a staggered manner, so that splitting and combining of white light can be realized.

In other examples, no detailed description is provided herein. It should be noted that the monochromatic light modulated by the first LCOS modulator 223, the second LCOS modulator 224, and the third LCOS modulator 225 is not limited; one monochromatic light composing the white light is in a first linear polarization state (such as S state or P state), and the other two monochromatic lights are in a second linear polarization state (such as P state or S state); the side surface of the light-combining prism 221 on which white light enters is one of two adjacent high-transmittance surfaces (for example, the first high-transmittance surface 221a or the second high-transmittance surface 221b), and the side surface of the light-combined light-exiting light-combining prism 221 is one of the other two adjacent high-transmittance surfaces (for example, the third high-transmittance surface 221c or the fourth high-transmittance surface 221d), which can be freely combined.

The optical path of the light in the modulation assembly 22 (i.e., the dodging assembly 121 is omitted here) is explained in the following with the situation shown in the above example.

(1) White light emitted from the light emitting module 11 passes through the first high-transmittance surface 221a and then enters the first phase-transmittance surface 221e, wherein the S-state red light is reflected by the first phase-transmittance surface 221e to the fourth phase-transmittance surface 221h, the S-state red light is reflected and enters the first high-transmittance surface 221a after passing through the fourth phase-transmittance surface 221h, the red light transmitted from the first high-transmittance surface 221a enters the first LCOS modulator 223 and is modulated by the first LCOS modulator 223 into P-state red light, the P-state red light is reflected by the first LCOS modulator 223 and sequentially passes through the first high-transmittance surface 221a, the fourth phase-transmittance surface 221h and the third phase-transmittance surface 221g, the red light is reflected by the third phase-transmittance surface 221g and enters the fourth high-transmittance surface 221d, and finally the modulated red light exits from the fourth high-transmittance surface 221 d;

(2) white light emitted from the light emitting module 11 passes through the first high-transmittance surface 221a and then enters the first intersecting surface 221e, wherein S-state blue light passes through the first intersecting surface 221e and then enters the second intersecting surface 221f, after passing through the second intersecting surface 221f, S-state blue light is reflected and enters the second high-transmittance surface 221b, blue light passing through the second high-transmittance surface 221b enters the second LCOS modulator 224 and is modulated into P-state blue light by the second LCOS modulator 224, the P-state blue light is reflected by the second LCOS modulator 224 and passes through the second high-transmittance surface 221b, the second intersecting surface 221f, the third intersecting surface 221g and the fourth high-transmittance surface 221d in sequence, and finally, the modulated blue light exits from the fourth high-transmittance surface 221 d;

(3) white light emitted from the light emitting module 11 passes through the first high-transmittance surface 221a and then enters the first intersection surface 221e, wherein green light in a P state passes through the first intersection surface 221e and then enters the second intersection surface 221f, green light in a P state passes through the second intersection surface 221f and then enters the third high-transmittance surface 221c, green light transmitted from the third high-transmittance surface 221c enters the third LCOS modulator 225 and is modulated into green light in an S state by the third LCOS modulator 225, the green light in the S state is reflected by the third LCOS modulator 225 and passes through the third high-transmittance surface 221c, the second intersection surface 221f, the third intersection surface 221g and the fourth high-transmittance surface 221d in sequence, and finally the modulated green light exits from the fourth high-transmittance surface 221 d.

In addition, for the second intersecting surface 221f, since the second intersecting surface 221f plays a role of polarization splitting of blue light and green light, in order to make the splitting effect (i.e., transmitting P-state light and reflecting S-state light) of blue light and green light better or make the splitting angle larger, the second intersecting surface 221f may be considered to provide the metal wire grid 222, for example, the metal wire grid 222 may be pasted on the second intersecting surface 221 f. For the fourth intersecting surface 221h, since the fourth intersecting surface 221h performs the polarization splitting function on the red light itself, the film coated surface having the polarization splitting characteristic can perform the polarization splitting function on the red light itself. Of course, in order to improve the polarization splitting effect of the fourth intersecting surface 221h, the metal wire grid 222 may be provided on the fourth intersecting surface 221 h.

In addition, the non-modulated light that is not modulated by the LCOS modulator passes through the light combining prism 221 and then returns from the first high-transmittance surface 221a along the original path of the optical path, which is not described herein again.

< lens Module 3>

Referring to fig. 1, the lens module 3 is connected to the modulation element 22, and the light emitted from the modulation element 22 can enter the lens module 3.

The projection display device provided by the application can comprise an engineering projector, a cinema projector, a laser television, a home theater, an education projector, a portable micro projector and the like, and can be placed on a horizontal plane and hung on a roof through a hanging column. For example, as shown in fig. 6, the projection display device may be placed on a horizontal surface such as a floor or a table, and used to enlarge and project image light onto a projection surface such as a wall or a screen.

It should be noted that, in order to balance the stability and uniformity of the projection brightness, the light-emitting brightness of the light source needs to be adjusted through the projection picture, because the total amount of the recycled non-modulated light in each projection image is always changed, and therefore, the projection brightness needs to be kept unchanged by adjusting the light-emitting power or light-emitting parameters of the light source.

Specifically, the intensity of light incident on the modulation module 2 needs to be stable and uniform. The light intensity P incident into the modulation module 2_LCOSLight intensity P of light emitted from the light source_LaserThe following relationship is satisfied:

P_Lcos＝α×P_laser+β×P_{Is not adjusted}(formula 1)

Where α is the light efficiency from the light source 11 to the modulation module 2, β is the light efficiency of the non-modulated light re-incident on the modulation module 2, and P_{Is not adjusted}Is the intensity of the unmodulated light.

The intensity P of the non-modulated light_{Is not adjusted}And the light intensity P projected to the position of the curtain_{Projection (projector)}The following relationship is satisfied:

P_{is not adjusted}＝P_lcOS-1/γ×P_{Projection (projector)}(formula 2)

Where γ is the light efficiency from the modulation module 2 to the lens module 3.

The light intensity P projected to the curtain position_{Projection (projector)}The gray value summation sigma of the projected picture meets the following relation:

P_{projection (projector)}Rho x sigma picture gray value (equation 3)

Wherein ρ is the ratio of the projection light intensity to the gray value.

By combining the above formulas, it can be obtained that the light intensity of the light source 11, i.e. the real-time light output power, is:

therefore, the light intensity P of the light source 11 can be adjusted_LaserTo ensure the brightness of the projection to be stable and uniform.

Since the parameter values of each projection display device are different, each projection display device needs to be calibrated, and meanwhile, since the specific parameters of each projection display device cannot be accurately obtained, each projection display device needs to be calibrated by other means.

The embodiment of the application also provides a calibration method of the projection display device, and the calibration method can be applied to the projection display device mentioned in the above. The calibration method comprises the following steps:

s1, projecting a pure color picture, changing parameters of the light source, measuring projection brightness corresponding to different parameters of the light source, normalizing the parameters of the light source and the projection brightness, and obtaining a first comparison table of the normalized parameters of the light source and the projection brightness;

in some embodiments, the light source may be a laser light source, such as a laser diode light source, a laser diode array light source, or a laser light source. The light source has the characteristic of small optical expansion, so that the emitted polarized light has small light spots, small light divergence angles and small optical expansion when entering the modulation module, the phenomenon that a large amount of light cannot be utilized due to large divergence angles is avoided, and the light utilization rate is improved. If other light sources are adopted, such as a bulb light source and an LED light source, the optical expansion of the light sources is far larger than that of a laser light source, so that the size of a light spot entering the modulator device meets the size of an incident surface, the divergence angle of light is expanded, and a large amount of light cannot be utilized by the modulation module and is absorbed and converted into heat outside the effective optical surface of the modulation module. Illustratively, the light sources include a red laser light source, a green laser light source, and a blue laser light source.

Of course, in an environment where the requirement on the light utilization rate is not high, a bulb or an LED light source may also be used as the light source.

In some embodiments, the parameter of the light source includes a current value or a duty ratio, and the light emitting intensity or power of the light source can be controlled by adjusting the current value or the duty ratio of the light source to achieve different projection brightness.

Normalization is a simplified calculation method, i.e. when a dimensional pixel value is transformed into a dimensionless expression, the transformed dimensional pixel value becomes a scalar so as to facilitate comparison and calculation of data.

The normalization can be performed in various calculation modes, and the pixel value can be normalized to be within a numerical range of 0-1, so that the calculation process is simplified in the subsequent calculation process.

S2, controlling the parameters of the light source to be unchanged, inputting pictures exceeding a preset value into the projection display device, measuring the sum of the gray values in each picture and the projection brightness corresponding to each picture, normalizing the sum of the gray values in each picture and the projection brightness to obtain a second comparison table of the normalized sum of the gray values in each picture and the projection brightness;

when the pictures or images are input into the projection display device, the gray value sum of each picture or image is simultaneously input into the projection display device as a digital signal, so that the relationship between the gray value sum and the projection brightness in each picture, namely the second comparison table, can be obtained.

S3, obtaining a third comparison table of the normalized light source parameters and the sum of gray values in each picture through the first comparison table and the second comparison table;

by using this intermediate variable of the projection brightness, it is thus possible to obtain the relation between the parameters of the light source and the sum of the gray values in each picture, i.e. a third comparison table.

And S4, writing the program corresponding to the third comparison table into the projection display device.

By writing the program corresponding to the third comparison table into the projection display device, when the projection display device is used, the light loss of the light source can be further reduced under the condition that the projection brightness of the projection display device is not changed, so that the average light efficiency of the projection display device can be improved.

The above description is only exemplary of the present application and should not be taken as limiting the present application, as any modification, equivalent replacement, or improvement made within the spirit and principle of the present application should be included in the scope of protection of the present application.

Claims

1. A projection display device, comprising:

2. A projection display device as claimed in claim 1, characterized in that the diffuser and the collimator lens are arranged eccentrically.

3. The projection display device according to claim 1, wherein the first transmission surface and the second transmission surface have microparticles made of resin and a binder for fixing the microparticles.

4. The projection display device of claim 1, wherein the dodging assembly sequentially comprises a fly-eye lens array and a focusing lens along a light path, the fly-eye lens array is disposed on a light-emitting side of the collimating lens, and the modulating assembly is disposed on a light-emitting side of the focusing lens.

5. The projection display device of claim 1, wherein the light source comprises a red laser light source, a green laser light source and a blue laser light source, a beam combining component for combining red light, green light and blue light is arranged on a light emitting side of the light source, and the diffusion sheet is arranged on the light emitting side of the beam combining component.

6. The projection display device according to any one of claims 1 to 5, wherein the light-combining prism comprises four right-angle prisms, the light-combining prism having four side faces and four intersecting faces formed by the four right-angle prisms;

7. A projection display device as claimed in claim 6, wherein one of the red, green and blue light emitted by the light source is of a first linear polarization state and the other two are of a second linear polarization state, the first and second linear polarization states being different.

8. A projection display device according to claim 7 wherein two of said intersecting surfaces are polarization splitting surfaces and two other of said intersecting surfaces are dichroic surfaces, said polarization splitting surfaces and said dichroic surfaces being staggered.

9. A projection display device as claimed in claim 8, characterized in that the polarization splitting plane, which is capable of splitting two monochromatic lights of different linear polarization states, is provided with a wire grid.

10. A projection display device as claimed in claim 8, characterized in that both polarization splitting planes are provided with a metal wire grid.

11. A method of calibrating a projection display device, comprising:

12. The calibration method of claim 11, wherein the light source comprises a red laser light source, a green laser light source, and a blue laser light source.

13. The calibration method of claim 11, wherein the parameter of the light source comprises a current value or a duty cycle.