CN113031287A

CN113031287A - Optical integrator, speckle suppression device and laser display system thereof

Info

Publication number: CN113031287A
Application number: CN201911255767.8A
Authority: CN
Inventors: 马宏
Original assignee: Juexin Electronics Wuxi Co ltd
Current assignee: Juexin Electronics Wuxi Co ltd
Priority date: 2019-12-09
Filing date: 2019-12-09
Publication date: 2021-06-25

Abstract

The invention provides an optical integrator, which sequentially comprises a first optical device and a second optical device from a light incidence side, wherein the first optical device and the second optical device are arranged in parallel, the first optical device comprises a first main surface and a second main surface, the first main surface is a cylindrical lens array, and the second main surface is a first reflecting layer; the second optical device includes a third principal surface and a fourth principal surface, the third principal surface is a lenticular lens array, the fourth principal surface is a second reflective layer, the third principal surface and the first principal surface are disposed oppositely, and the lenticular lens array of the third principal surface and the lenticular lens array of the first principal surface are orthogonally staggered. The optical integrator is mainly applied to the field of laser display with coherent light as a light source, and has a simple structure and easy processing; the speckle suppression device can be driven by an MEMS system, has low power consumption and low noise, and is high in equipment and module reliability, the sub-beam has time-varying property, and the speckle suppression effect is good.

Description

Optical integrator, speckle suppression device and laser display system thereof

Technical Field

The invention relates to the field of optical display, in particular to an optical integrator, a speckle suppression device and a laser display system thereof.

Background

Speckle is a granular speckle of random intensity distribution that occurs when a coherent light source, such as a laser light source, illuminates an optically rough surface or passes through an inhomogeneous medium. Coherent light beams, such as laser light, are diffusely reflected off the optically rough surface to form randomly distributed light with phase differences in space. The light generated by diffuse reflection has the same frequency as the incident light, and is interfered after meeting in space, so that the light intensity is randomly distributed in the space to form speckles.

Speckle has different meanings in different applications and fields. In coherent light display systems, such as laser display systems, speckle can cause a lack of a portion of the image information displayed, reducing the resolution of the display, and thus can be detrimental to coherent light display systems. In laser projection display systems, the primary parameter measuring speckle is speckle contrast, which is defined as the ratio of the standard deviation of the intensity of light on a uniformly illuminated screen to the mean. When the speckle phenomenon is obvious, the C value is large; otherwise, C will go to zero. To make the speckle in the image imperceptible to the human eye, the speckle contrast value should be less than 4%. According to related studies, when the speckle contrast is suppressed below 4%, the human visual system cannot identify the speckle in the projected image.

From the cause analysis of the speckle, the root cause of the speckle is that the illuminating beam has excellent coherence. Therefore, the fundamental method of speckle suppression is to reduce the coherence of the illuminating beam. The existing speckle suppression technologies can be broadly divided into three categories: the optical properties of the laser beam are influenced temporally and/or spatially by driving the multi-laser to form a low-coherence laser light source or to average the resulting speckle brightness, by compensating for the human vision by means of an oscillating projection screen, by adding optical elements with specific functions in the beam path. The total output light power is constant due to the light emitting characteristics of the lasers, and the power consumption for driving the multiple lasers is larger than that for driving a single laser. Meanwhile, the number of lasers is increased, and the production cost is increased. The technique of realizing speckle suppression by vibrating the projection screen has many limitations in practical use. Therefore, when speckle suppression is performed, an optical element with a specific function is added to an optical path, so that the speckle suppression device has the widest application prospect at the present stage.

In speckle suppression technology, optical elements mainly used in the prior art include various types of scattering sheets, diffractive optical elements, microlens arrays, and MEMS micromirrors with roughened surfaces.

The scattering sheet has quite limited speckle suppression effect in a static state, and needs to be driven by a driving system, and the light beams form sub-beams with time-varying random phases after penetrating through the rotating and/or vibrating scattering sheet. The speckle effect formed by the sub-beams is small and the overall effect is reduced after the sub-beams are overlapped with each other. However, the addition of an additional driving system in the laser display system may not only adversely affect the reliability of the precision optical system, but also may generate negative effects such as noise, and is also not conducive to the integration and miniaturization of the system module, thereby limiting the commercial application value of the system module.

The diffractive optical element can split the transmitted light beam in a static state, and the diffractive optical element has a micro-nano structure, so that the split sub-beams have random phases, and the speckle effect formed by the sub-beams is small and the overall effect is reduced after the sub-beams are overlapped with each other. However, since a specific diffractive optical element can split only a coherent light beam having a specific wavelength, there is a certain limitation in use.

The micro lens array refers to the arrangement and combination of a certain number of micro-nano scale spherical or free-form surface lenses. The periodic size of the microlens array is typically 500nm-50 μm. The micro lens array can also split the light beam in a static state, and has better beam splitting and beam homogenizing effects compared with a diffraction optical element. Typically, microlens arrays typically require two arrays to be used in combination. Because the beam homogenizing effect of a single micro-lens array is not as good as that of a micro-lens array group, the brightness distribution in the light spot is uneven after beam homogenizing, and the speckle suppression effect is poor. The use of multiple microlens arrays increases the module size. Meanwhile, when the micro-lens array pair is used, two micro-lens arrays need to be mutually corresponding, and the requirements on the precision of the size and the position are high. In addition, due to the manufacturing process, when a lens array (not only a micro lens array) is used, a scattering phenomenon inevitably occurs, which causes energy loss and reduction of spot brightness, and is disadvantageous to laser display.

The surface roughened MEMS micro-mirror causes the reflected beam to acquire a phase with time-variability by vibrating in one or more dimensions. However, the prior art still has certain disadvantages, such as complex process, poor stability of the finished product, high cost, low yield, etc. Meanwhile, according to several documents, the height or depth of the protrusions formed by roughening needs to be 1/4-2 times of the incident wavelength. Therefore, the requirement for the precision of the micro/nano structure on the surface of the roughened MEMS micro-mirror is high, so that a certain limit exists in practical use.

Fly-eye optical integrators are typically composed of several lenses and a set of microlens array pairs. The characteristic that the light beam can form a light beam consisting of a plurality of sub-light beams after penetrating through the fly-eye optical integrator is utilized, the sub-light beams forming the light beam respectively form speckles with weak energy when in projection display, and the formed speckle effects are mutually overlapped in the human eye visual persistence time, so that the integral speckle phenomenon is suppressed while the integral brightness of the light spot is maintained.

Therefore, there is a need to provide a new optical integrator and a speckle reduction device for solving the inherent problem of laser speckle in coherent light (e.g., laser) display, so as to achieve efficient laser speckle reduction on various common projection surfaces at low cost and low power consumption while maintaining the integration of modules.

Disclosure of Invention

In order to solve the technical problem, the invention discloses an optical integrator, a speckle suppression device and a laser display system thereof.

In a first aspect of the present invention, an optical integrator includes, in order from a light incident side, a first optical device and a second optical device, the first optical device and the second optical device being arranged in parallel to each other, the first optical device including a first principal surface and a second principal surface, both of which are lenticular lens arrays, and the lenticular lens array of the first principal surface and the lenticular lens array of the second principal surface being symmetrically arranged, the first principal surface and the second principal surface having a predetermined refractive power in a first direction within a plane orthogonal to an optical axis and having no refractive power in a second direction orthogonal to the first direction within the plane orthogonal to the optical axis;

the second optical device includes a third principal surface and a fourth principal surface, both of which are lenticular lens arrays, and the lenticular lens arrays of the third principal surface and the fourth principal surface are symmetrically disposed, the third principal surface and the fourth principal surface having a predetermined refractive power in the second direction and no refractive power in the first direction;

the lenticular lens array comprises a plurality of unit lenticular lenses arranged side by side in an array.

Further, the distance between the first main surface and the second main surface is a focal length F of the lenticular lens array of the first optical device, and the distance between the third main surface and the fourth main surface is a focal length F of the lenticular lens array of the second optical device.

In a second aspect of the present invention, an optical integrator includes, in order from a light incident side, a first optical device and a second optical device, the first optical device and the second optical device being arranged in parallel with each other,

the first optical device includes a first main surface and a second main surface, the first main surface and the second main surface are both lenticular lens arrays, and the lenticular lens arrays of the first main surface and the lenticular lens arrays of the second main surface are alternately arranged,

the second optical device comprises a third main surface and a fourth main surface, the third main surface and the fourth main surface are both lenticular lens arrays, and the lenticular lens arrays of the third main surface and the lenticular lens arrays of the fourth main surface are arranged in an interlaced manner,

the first and third main surfaces have a predetermined refractive power in a first direction within a plane orthogonal to an optical axis and have no refractive power in a second direction orthogonal to the first direction within the plane orthogonal to the optical axis; the second and fourth major faces having a predetermined refractive power in the second direction and no refractive power in the first direction;

In a third aspect of the present invention, an optical integrator includes, in order from a light incident side, a first optical device and a second optical device, the first optical device and the second optical device being arranged in parallel with each other,

the first optical device comprises a first main surface and a second main surface, wherein the first main surface is a cylindrical lens array, and the second main surface is a first reflecting layer;

the second optical device comprises a third main surface and a fourth main surface, the third main surface is a cylindrical lens array, the fourth main surface is a second reflecting layer, and the cylindrical lens array on the third main surface and the cylindrical lens array on the first main surface are orthogonally arranged in an alternating mode;

Further, the first reflective layer is a mirror or a reflective film.

Further, the distance between the first main face and the second main face is f/2, where f is the focal length of the lenticular lens array of the first main face.

Further, the second reflective layer is any one of a mirror, a reflective film or a MEMS micro-mirror.

Further, the distance between the third main surface and the fourth main surface is F/2, wherein F is the focal length of the lenticular lens array of the third main surface.

In one embodiment, the second reflective layer is a MEMS micro-mirror that can be driven by a MEMS system to translate or rotate in/out of plane in at least one dimension.

In a fourth aspect of the present invention, an optical integrator includes, in order from a light incident side, a first optical device and a second optical device, the first optical device and the second optical device being arranged in parallel to each other, the first optical device including a first principal surface and a second principal surface, the first principal surface and the second principal surface being both lenticular lens arrays, and the lenticular lens array of the first principal surface and the lenticular lens array of the second principal surface being symmetrically arranged;

Further, the distance between the first main surface and the second main surface is a focal length f of the first optical device. The distance between the third main face and the fourth main face is F/2, wherein F is the focal length of the lenticular lens array of the third main face.

In a fifth aspect of the present invention, an optical integrator includes, in order from a light incident side, a first optical device and a second optical device, the first optical device and the second optical device being arranged in parallel to each other, the first optical device including a first principal surface and a second principal surface, the first principal surface and the second principal surface being both lenticular lens arrays, and the lenticular lens arrays of the first principal surface and the lenticular lens arrays of the second principal surface being arranged alternately;

the second optical device is a reflecting device;

Further, the distance between the second main surface and the reflecting device is half of the focal length f of the lenticular lens array of the second main surface, which is f/2.

Further, the distance between the first main face and the reflecting means is denoted by d, where d is related to the focal length and refractive index of the lenticular lens array constituting the first main face.

Further, the reflecting device is any one of a mirror, a reflective film or a MEMS micro-mirror.

In one embodiment, the reflective device is a MEMS micro-mirror that can be driven by a MEMS system to translate or rotate in/out of plane in at least one dimension.

In a sixth aspect of the present invention, a speckle suppression apparatus includes the above-mentioned optical integrator, and further includes a beam expander and a first lens, where the beam expander, the optical integrator, and the first lens are sequentially disposed along a light path, and the optical integrator is configured to split and homogenize coherent light, so as to homogenize speckles.

In a seventh aspect of the present invention, a speckle reduction apparatus includes a beam expander, an optical integrator, and a first lens, which are sequentially disposed along an optical path, the optical integrator includes a first optical device and a second optical device, the first optical device and the second optical device are disposed in parallel with each other,

the first optical device is a micro-lens array or a Fresnel lens array, and the second optical device is a MEMS micro-mirror.

Further, the MEMS micro-mirror can be driven by the MEMS system to perform out-of-plane translation in the vertical direction.

In an eighth aspect of the present invention, a laser display system comprises the speckle suppressing apparatus, and further comprises a laser light source, a beam combiner, and a micro-mirror device, wherein the laser light source, the beam combiner, the speckle suppressing apparatus, and the micro-mirror device are sequentially arranged,

the laser light source is used for emitting laser beams of at least one color;

the beam combiner is used for forming the laser beam into combined beam light;

the speckle suppression device is used for expanding, splitting, homogenizing and converging the combined beam to generate an emergent beam consisting of a plurality of sub-beams;

the micro-mirror device is used for reflecting the emergent light beam into a scanning light beam and projecting the scanning light beam to a projection surface for scanning display;

the speckle suppression device comprises a beam expander, an optical integrator and a first lens.

In the ninth aspect of the invention, a laser display system comprises the speckle suppression device, a laser light source, a beam combiner and a micro-mirror device, which are sequentially arranged,

the laser light source is used for emitting laser beams of at least one color;

the beam combiner is used for forming the laser beam into combined beam light;

the micro-mirror device is used for forming reflected light by the beam combination light and emitting the reflected light into the speckle suppression device;

the speckle suppression device is used for expanding, splitting, homogenizing and converging the reflected light, generating a scanning light beam consisting of a plurality of sub-light beams, and projecting the scanning light beam to a projection surface for scanning and displaying;

By adopting the technical scheme, the invention has the following beneficial effects:

1) the structure of the optical integrator is mainly applied to the technical field of laser display by taking coherent light as a light source, and is simpler and easier to process compared with the traditional micro-lens array structure;

2) the optical integrator has good applicability, can be matched with part of the prior art for use, such as a vibration screen technology, a speckle suppression technology based on a roughened mirror surface and the like, and does not need to introduce additional optical components, such as a rotating scattering sheet, an optical fiber and the like, so that the complexity of the system is reduced, further speckle suppression is realized, and the defect of the part of the prior art in the speckle suppression degree is overcome;

3) the speckle suppression device can be driven by an MEMS system, has low power consumption and basically no noise during working, and can avoid the damage to other components in the module caused by factors such as vibration and the like possibly caused by using other driving modes, thereby improving the reliability of equipment and the module;

4) the speckle suppression device has the advantages that through the use of the reflection structure, the equipment has more possibility in spatial arrangement during integration;

5) the speckle suppression device has lower requirement on the position precision of the lens array forming the compound eye structure, and is more beneficial to large-scale production in a mode with lower use cost;

6) the speckle suppression device provided by the invention does not need to be matched with a vibrating projection screen for use, can realize a designed speckle suppression effect on a static screen, and improves the convenience and practicability of the system.

7) The speckle suppression device can be integrated in a display module of laser or other coherent light, suppresses the inherent speckle phenomenon in coherent light display, improves the resolution of the display module, and is small in size and favorable for being integrated in an original laser display system;

8) the optical integrator of the speckle suppression device can be manufactured by the traditional manufacturing process, such as photoetching, etching and the like, and can also be manufactured repeatedly with stable process in a low-cost and high-yield mode by a nano-imprinting technology and a nano-printing technology;

9) when the device works, after collimated laser beams generated by a coherent light source (such as a laser) are incident to the speckle suppression device, the collimated laser beams transmit and form beams with the size in a certain range, which are formed by a plurality of sub-beams, and the beams are reflected into scanning beams by an MEMS micro-mirror device in a module, the sub-beams forming the scanning beams respectively form speckle patterns with smaller energy when the projection surface images, the speckle pattern effects with smaller energy are mutually overlapped, the overall effect of speckles is homogenized, the brightness is weakened, and the speckles appearing during imaging are suppressed.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is a schematic perspective view of an optical integrator according to example 1;

FIG. 2 is a side view of the optical integrator of example 1;

FIG. 3 is a schematic perspective view of an optical integrator according to example 2;

FIG. 4 is a side view of the optical integrator of example 2;

FIG. 5 is a perspective view of an optical integrator according to example 3;

FIG. 6 is a schematic view of a speckle reduction apparatus according to embodiment 4;

FIG. 7 is a perspective view of an optical integrator according to example 5;

FIG. 8 is a schematic view of a speckle reduction apparatus according to embodiment 6;

FIG. 9 is a perspective view of an optical integrator of example 7;

FIG. 10 is a schematic view of a speckle reduction apparatus according to embodiment 8;

FIG. 11 is a schematic view of a speckle reduction apparatus according to embodiment 9;

FIG. 12 is a schematic view of a speckle reduction apparatus according to embodiment 10;

FIG. 13 is a schematic view of an optical apparatus according to example 11;

FIG. 14 is a schematic view of an optical apparatus according to example 12.

The following is a supplementary description of the drawings:

100-an optical integrator, 101-a first optical device; 101 a-a first major face; 101 b-a second major face; 102-a second optical device; 102 a-a third major face; 102 b-a fourth major face;

200-an optical integrator, 201-a first optical device; 201 a-a first major face; 201 b-a second major face; 202-a second optical device; 202 a-a third major face; 202 b-a fourth major face;

300-optical integrator, 301-first optics; 301 a-first major face; 301 b-a second major face; 302-a second optical device; 302 a-third major face; 302 b-a fourth major face; 303-a beam expander; 303 a-second lens, 303 b-third lens; 304-a first lens;

400-optical integrator, 401-first optics; 401 a-a first major face; 401 b-a second major face; 402-a second optical device; 402 a-third major face; 402 b-a fourth major face; 403-a beam expander; 403 a-second lens, 403 b-third lens; 404-a first lens;

500-an optical integrator, 501-a first optical device; 501 a-a first major face; 501 b-a second major face; 502-a second optical device; 503-a beam expander; 503 a-second lens, 503 b-third lens; 504-a first lens;

600-an optical integrator, 601-a first optical device; 602-a second optical device; 603-a beam expander; 603 a-second lens, 603 b-third lens; 604-a first lens;

700-optical integrator, 701-first optics; 702-a second optical device; 703-a beam expander; 703 a-second lens, 703 b-third lens; 704-a first lens;

801-laser light source, 802-beam combiner, 803-speckle suppression device; 803 a-a beam expander; 803 b-optical integrator; 803 c-first lens; 804-a micro-mirror device;

901-laser source, 902-beam combiner, 903-micro mirror device; 904-speckle reduction means; 904 a-beam expander; 904 b-optical integrator; 904 c-first lens.

Detailed Description

The technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Reference herein to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic may be included in at least one implementation of the invention. Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. Moreover, the terms "first," "second," and the like are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in sequences other than those illustrated or described herein.

Example 1:

the XYZ rectangular coordinate system shown in fig. 1 is set, the X axis (first direction) and the Y axis (second direction) are set within the plane of the first main surface 101a of the first optical device 100, the unit lenticular lens array direction along the first main surface 101a is set as the X axis, and the Z axis (third direction) is set along the normal direction of the first main surface of the first optical device.

As shown in fig. 1 and 2, an optical integrator 100 includes, in order from a light incident side, a first optical device 101 and a second optical device 102, the first optical device 101 and the second optical device 102 being arranged in parallel with each other,

the first optical device 101 includes a first principal surface 101a and a second principal surface 101b, both of the first principal surface 101a and the second principal surface 101b are lenticular lens arrays, and the lenticular lens array of the first principal surface 101a and the lenticular lens array of the second principal surface 101b are symmetrically arranged, the first principal surface 101a and the second principal surface 101b have a predetermined refractive power in a first direction within a plane orthogonal to an optical axis, and have no refractive power in a second direction orthogonal to the first direction within the plane orthogonal to the optical axis;

the second optical device 102 includes a third main surface 102a and a fourth main surface 102b, the third main surface 102a and the fourth main surface 102b are both lenticular lens arrays, and the lenticular lens array of the third main surface 102a and the lenticular lens array of the fourth main surface 102b are symmetrically arranged, the third main surface 102a and the fourth main surface 102b have a predetermined refractive power in the second direction, and no refractive power in the first direction;

The first main face 101a, the third main face 102a, the second main face 101b and the fourth main face 102b are all convex cylindrical surfaces with convex curves in cross section.

The distance between the first main surface 101a and the second main surface 101b is a focal length F of the lenticular lens array of the first optical device 101, and the distance between the third main surface 102a and the fourth main surface 102b is a focal length F of the lenticular lens array of the second optical device 102.

The laser beam expanded and collimated by the beam expander (not shown in the figure) enters from the first main surface 101a of the first optical component and is transmitted from the second main surface 101b, and is split in a corresponding one dimension. The split sub-beams enter the second optical element 102 from the third main surface 102a, are transmitted from the fourth main surface 102b, and are split again in the respective other dimension. The beam splitting, beam expanding and beam homogenizing effects of the first optical device 101 and the second optical device 102 on the laser beam in two orthogonal dimensions are the same as those of the conventional optical integrator 100 using a micro-lens array pair as a compound eye structure.

In addition, the laser beam may also be incident on the second optical device 102 from the fourth main surface 102b, pass through the third main surface 102a and the second main surface 101b, and finally be transmitted out of the first optical device 101 from the first main surface 101a, so as to achieve the same beam splitting and homogenizing effect on the laser beam as that of the conventional fly-eye integrator.

Example 2:

an XYZ rectangular coordinate system shown in fig. 3 is set, an X axis (first direction) and a Y axis (second direction) are set within the plane of the first main surface 201a of the first optical device 201, an X axis is set along the first main surface 201a in the unit lenticular lens arrangement direction, and a Z axis (third direction) is set along the normal direction of the first main surface 201a of the first optical device 201.

As shown in fig. 3 and 4, an optical integrator 200 includes, in order from a light incident side, a first optical device 201 and a second optical device 202, the first optical device 201 and the second optical device 202 being arranged in parallel with each other,

the first optical device 201 comprises a first main surface 201a and a second main surface 201b, the first main surface 201a and the second main surface 201b are both lenticular lens arrays, and the lenticular lens arrays of the first main surface 201a and the lenticular lens arrays of the second main surface 201b are arranged alternately,

the second optical device 202 includes a third main surface 202a and a fourth main surface 202b, the third main surface 202a and the fourth main surface 202b are both lenticular lens arrays, and the lenticular lens arrays of the third main surface 202a and the lenticular lens arrays of the fourth main surface 202b are alternately arranged,

the first main surface 201a and the third main surface 202a have a predetermined refractive power in a first direction within a plane orthogonal to an optical axis and have no refractive power in a second direction orthogonal to the first direction within the plane orthogonal to the optical axis; the second main face 201b and the fourth main face 202b have a predetermined refractive power in the second direction, and no refractive power in the first direction;

The distance between the first main face 201a and the third main face 202a is denoted by D, and the distance between the second main face 201b and the fourth main face 202b is denoted by D. The magnitudes of D and D are related to the focal lengths F and the refractive indices of the lenticular lenses constituting the first and second major faces 201a and 201 b.

The laser beam expanded and collimated by a beam expander (not shown in the figure) enters from the first main surface 201a of the first optical device 201, is transmitted from the second main surface 201b, and is split in two dimensions. The split sub-beams enter the optical second optical device 202 from the third main surface 202a, are transmitted from the fourth main surface 202b, and are split, expanded, and homogenized again in two dimensions. The beam splitting, beam expanding and beam homogenizing effects of the first optical device 201 and the second optical device 202 on the laser beam in two orthogonal dimensions are the same as those of the conventional optical integrator 200 using a micro-lens array pair as a compound eye structure.

The laser beam may first enter the second optical device 202 from the fourth main surface 202b, then pass through the third main surface 202a and the second main surface 201b, and finally be transmitted from the first main surface 201a to the first optical device 201.

Example 3:

as shown in fig. 5, an optical integrator 300 includes, in order from a light incident side, a first optical device 301 and a second optical device 302, the first optical device 301 and the second optical device 302 being arranged in parallel with each other,

the first optical device 301 includes a first principal surface 301a and a second principal surface 301b, the first principal surface 301a being a lenticular lens array, the second principal surface 301b being a first reflective layer;

the second optical device 302 includes a third main surface 302a and a fourth main surface 302b, the third main surface 302a is a lenticular lens array, the fourth main surface 302b is a second reflective layer, and the lenticular lens array of the third main surface 302a and the lenticular lens array of the first main surface 301a are orthogonally staggered;

The first reflective layer is a mirror or a reflective film.

The distance between the first main face 301a and the second main face 301b is f/2, where f is the focal length of the lenticular lens array of the first main face 301 a.

The second reflecting layer is any one of a reflecting mirror, a reflecting film or a MEMS micro-mirror.

The distance between the third main face 302a and the fourth main face 302b is F/2, where F is the focal length of the lenticular lens array of the third main face 302 a.

The second reflective layer is a MEMS micro-mirror that can be actuated by a MEMS system to translate or rotate in/out of plane in at least one dimension.

The laser beam with larger size after expanded and collimated by a beam expander (not shown in the figure) is incident on the first optical device 301 of the optical integrator 300 and is split into a plurality of sub-beams in a corresponding dimension. The laser beam enters the first optical device 301 through the first main surface 301a, is reflected by the second main surface 301b, and is transmitted through the first main surface 301a again. The sub-beams enter the second optical element 302 through the third main surface 302a, are reflected by the fourth main surface 302b, are transmitted through the third main surface 302a again, are split again in the corresponding one dimension, and are expanded and homogenized outside the focal length.

In addition, the sequence and the driving of the incident first optical device 301 and the incident second optical device 302 are switched, and the final beam expanding and homogenizing effects on the light beams are the same.

Example 4:

as shown in fig. 6, a speckle reduction device, the optical integrator 300 according to embodiment 3, further includes a beam expander 303 and a first lens 304, and the beam expander 303, the optical integrator 300 and the first lens 304 are sequentially disposed along an optical path.

The beam expander 303 includes a second lens 303a and a third lens 303 b.

When the laser beam enters the speckle suppressing apparatus, the laser beam is expanded by the beam expander 303 and is re-collimated into a laser beam with a larger size. The laser beam having a large size enters the first optical device 301 of the optical integrator 300, enters the first optical device 301 through the first main surface 301a, is reflected by the second main surface 301b, and is transmitted through the first main surface 301a again. The sub-beams enter the second optical element 302 through the third main surface 302a, are reflected by the fourth main surface 302b, are transmitted through the third main surface 302a again, are split again in the corresponding one dimension, and are expanded and homogenized outside the focal length. The expanded and homogenized laser beam composed of a plurality of sub-beams is re-collimated by the first lens 304 into a laser beam with a size within a certain range and capable of being used for laser projection display.

Example 5:

as shown in fig. 7, an optical integrator 400 includes, in order from a light incident side, a first optical device 401 and a second optical device 402, the first optical device 401 and the second optical device 402 being arranged in parallel with each other,

the first optical device 401 includes a first main surface 401a and a second main surface 401b, the first main surface 401a and the second main surface 401b are both lenticular lens arrays, and the lenticular lens array of the first main surface 401a and the lenticular lens array of the second main surface 401b are symmetrically arranged;

the second optical device 402 includes a third principal surface 402a and a fourth principal surface 402b, the third principal surface 402a is a lenticular lens array, the fourth principal surface 402b is a second reflective layer, and the lenticular lens array of the third principal surface 402a and the lenticular lens array of the first principal surface 401a are orthogonally staggered;

The distance between the first main surface 401a and the second main surface 401b is the focal length f of the first optical device 401. The distance between the third main face 402a and the fourth main face 402b is F/2, where F is the focal length of the lenticular lens array of the third main face 402 a.

The laser beam expanded and collimated by a beam expander (not shown in the figure) enters from the first main surface 401a of the first optical component and is transmitted from the second main surface 401b, and is split in a corresponding one dimension. The split sub-beams enter the second optical device 402 from the third main surface 402a, are reflected by the fourth main surface 402b, are transmitted again from the third main surface 402a, are split again in the corresponding one dimension, and are expanded and homogenized outside the focal length.

In addition, the sequence and the driving of the incident first optical device 401 and the incident second optical device 402 are switched, and the final beam expanding and homogenizing effects on the light beams are the same.

Example 6:

as shown in fig. 8, a speckle reduction device, the optical integrator 400 according to embodiment 5, further includes a beam expander 403 and a first lens 404, and the beam expander 403, the optical integrator 400 and the first lens 404 are sequentially disposed along an optical path.

The beam expander 403 includes a second lens 403a and a third lens 403 b.

When the laser beam enters the speckle reduction device, the laser beam is expanded by the beam expander 403 and is re-collimated into a laser beam with a larger size. The laser beam having a large size enters the first optical device 401 of the optical integrator 400, enters the first optical device 401 from the first main surface 401a, and then is transmitted through the second main surface 401 b. The sub-beams enter the second optical element 402 from the third main surface 402a, are reflected by the fourth main surface 402b, are transmitted again from the third main surface 402a, are split again in the corresponding one dimension, and are expanded and homogenized outside the focal length. The expanded and homogenized laser beam composed of a plurality of sub-beams is re-collimated by the first lens 404 into a laser beam with a size within a certain range and capable of being used for laser projection display.

Example 7:

as shown in fig. 9, an optical integrator 500 includes, in order from a light incident side, a first optical device 501 and a second optical device 502, the first optical device 501 and the second optical device 502 being arranged in parallel with each other,

the first optical device 501 comprises a first main surface 501a and a second main surface 501b, the first main surface 501a and the second main surface 501b are both lenticular lens arrays, and the lenticular lens arrays of the first main surface 501a and the lenticular lens arrays of the second main surface 501b are arranged in a staggered manner;

the second optical device 502 is a reflective device;

The distance between the second main surface 501b and the reflection device is half of the focal length f of the lenticular lens array of the second main surface 501b, i.e. f/2.

The distance between the first main face 501a and the reflecting means is denoted by d, where d is related to the focal length and refractive index of the lenticular lens array constituting the first main face 501 a.

The reflecting device is a MEMS micro-mirror that can be driven by a MEMS system to translate or rotate in/out of plane in at least one dimension.

The aperture of the lenticular lens array on the first main surface 501a is different from the aperture of the lenticular lens array on the second main surface 501 b.

The laser beam expanded and collimated by the beam expander (not shown in the figure) enters from the first main surface 501a of the first optical component and is transmitted from the second main surface 501b, and is split into a plurality of sub-beams in a corresponding dimension. The split sub-beams are reflected back to the first optical device 501 by a reflecting means placed at a distance bf/2 from the second main face 501. The sub-beams are reflected back to the first optical element 501, enter from the second main surface 501b, are transmitted from the first main surface 501a, are split again in two dimensions, and are expanded and homogenized outside the focal length.

Example 8:

as shown in fig. 10, a speckle reduction device is an optical integrator 500 according to embodiment 7, further including a beam expander 503 and a first lens 504, where the beam expander 503, the optical integrator 500, and the first lens 504 are sequentially disposed along an optical path.

The beam expander 503 includes a second lens 503a and a third lens 503 b.

When the laser beam enters the speckle reduction device, the laser beam is expanded by the beam expander 503 and is re-collimated into a laser beam with a larger size. The laser beam with a larger size enters the first optical device 501 of the optical integrator 500, enters from the first main surface 501a of the first optical device and transmits from the second main surface 501b, and is split into a plurality of sub-beams in a corresponding dimension. The split sub-beams are reflected back to the first optical device 501 by a reflecting means placed at a distance bf/2 from the second main face 501. The sub-beams are reflected back to the first optical element 501, enter from the second main surface 501b, are transmitted from the first main surface 501a, are split again in two dimensions, and are expanded and homogenized outside the focal length. The expanded and homogenized laser beam composed of a plurality of sub-beams is re-collimated by the first lens 504 into a laser beam with a size within a certain range and capable of being used for laser projection display.

Example 9:

as shown in fig. 11, a speckle reduction device includes a beam expander 603, an optical integrator 600 and a first lens 604, which are sequentially arranged along an optical path, wherein the optical integrator 600 includes a first optical device 601 and a second optical device 602, the first optical device 601 and the second optical device 602 are arranged in parallel with each other,

the first optical device 601 is a micro lens array, and the second optical device 602 is a MEMS micro mirror.

The beam expander 603 includes a second lens 603a and a third lens 603 b.

The focal length of the microlens array is denoted by f. The distance between one side of the micro lens array facing the MEMS micro mirror and the MEMS micro mirror is f/2.

The MEMS micro-mirror can be driven by the MEMS system to perform in-plane/out-of-plane translation or rotation in at least one dimension.

When the laser beam enters the speckle suppressing device, the laser beam is expanded by the beam expander 603 and is re-collimated into a laser beam with a larger size. The larger laser beam is incident on the first optics 601 (microlens array) of the optical integrator 600 and split into several sub-beams. The split sub-beams are reflected by the MEMS micro-mirror device back to the first optical device 601. And transmitting the sub-beams out of the micro-lens array again, and further splitting, expanding and homogenizing the beams into laser beams consisting of a plurality of sub-beams. The laser beam composed of several sub-beams is re-collimated by the first lens 604 into a laser beam having a size within a certain range that can be used for laser projection display.

Example 10:

as shown in fig. 12, a speckle reduction device includes a beam expander 703, an optical integrator 700, and a first lens 704, which are sequentially disposed along an optical path, where the optical integrator 700 includes a first optical device 701 and a second optical device 702, the first optical device 701 and the second optical device 702 are disposed in parallel with each other,

the first optical device 701 is a fresnel lens array, and the second optical device 702 is a MEMS micromirror.

The beam expander 703 comprises a second lens 703a and a third lens 703 b. The beam expander is also called a telecentric lens (telecentric lens).

The focal length of the fresnel lens array is denoted by f. The distance between one side of the Fresnel lens array facing the MEMS micro-mirror and the MEMS micro-mirror is f/2.

When the laser beam enters the speckle suppressing apparatus, the laser beam is expanded by the beam expander 703 and is re-collimated into a laser beam with a larger size. The larger laser beam is incident on the first optics 701 (fresnel lens array) of the optical integrator 700 and split into several sub-beams. The split sub-beams are reflected by the MEMS micro-mirror device back to the first optical device 701. And transmitting the sub-beams out of the Fresnel lens array again, and further splitting, expanding and homogenizing the beams into laser beams consisting of a plurality of sub-beams. The laser beam composed of several sub-beams is re-collimated by the first lens 704 into a laser beam having a size within a certain range that can be used for laser projection display.

Example 11:

as shown in fig. 13, a laser display system includes a laser source 801, a beam combiner 802, a speckle reduction device 803 and a micro-mirror device 804 arranged in sequence,

the laser light source 801 is used for emitting laser beams;

the beam combiner 802 is configured to combine the laser beams into a combined beam;

the speckle suppression device 803 is used for expanding, splitting, homogenizing and converging the combined beam to generate an emergent beam composed of a plurality of sub-beams;

the micro-mirror device 804 is used for reflecting the emergent light beam into a scanning light beam and projecting the scanning light beam to a projection surface for scanning display;

the speckle reduction device 803 includes a beam expander 803a, an optical integrator 803b, and a first lens 803 c.

The optical integrator 803b may be any one of the optical integrators described in the above embodiments.

The light beam is split into a plurality of small sub-beams in one corresponding dimension by a first optical device with a cylindrical lens array as in embodiment 1. The small sub-beams pass through a second optical device with a cylindrical lens array as in example 1, and are expanded and homogenized in two dimensions to form a laser beam consisting of a plurality of larger sub-beams. The laser beam is converged into a beam with a size corresponding to the size of the scanning beam by the first lens 803c, reflected into the scanning beam by the MEMS micro-mirror and projected onto the projection surface for scanning display.

The beam expander 803a is a lens group or a fresnel lens.

Example 12:

as shown in fig. 14, a laser display system includes a laser light source 901, a beam combiner 902, a micro mirror device 903 and a speckle reduction device 904 arranged in sequence,

the laser light source 901 is used for emitting laser beams;

the beam combiner 902 is configured to combine the laser beams into a combined beam;

the micromirror device 903 is used for making the beam combination light form reflected light to enter the speckle suppression device 904;

the speckle suppression device 904 is used for expanding, splitting, homogenizing and converging the reflected light, generating a scanning beam consisting of a plurality of sub-beams, and projecting the scanning beam to a projection surface for scanning and displaying;

the speckle reduction device 904 includes a beam expander 904a, an optical integrator 904b, and a first lens 904 c.

The optical integrator 904b may be any one of the optical integrators described in the above embodiments.

The light beam is split into a plurality of small sub-beams in one corresponding dimension by a first optical device with a cylindrical lens array as in embodiment 1. The small sub-beams pass through a second optical device with a cylindrical lens array as in example 1, and are expanded and homogenized in two dimensions to form a laser beam consisting of a plurality of larger sub-beams. The laser beam passes through the first lens 904c, is converged into a beam with a size according with the size of the scanning beam, is reflected into a scanning beam by the MEMS micro-mirror, and is projected to the projection surface for scanning and displaying.

the structure of the optical integrator is mainly applied to the technical field of laser display by taking coherent light as a light source, and is simpler and easier to process compared with the traditional micro-lens array type structure.

The optical integrator has good applicability, can be matched with part of the prior art for use, such as a vibrating screen technology, a speckle suppression technology based on a roughened mirror surface and the like, and does not need to introduce additional optical components, such as a rotating scattering sheet, an optical fiber and the like, so that the complexity of a system is reduced, further speckle suppression is realized, and the defect of the part of the prior art in the speckle suppression degree is overcome.

The speckle suppression device can be driven by an MEMS system, has low power consumption and basically no noise during working, and can avoid damage to other components in the module caused by factors such as vibration and the like possibly caused by using other driving modes, so that the reliability of equipment and the module is improved, and meanwhile, the moving MEMS micro-mirror device enables sub-beams generated by the device to have time-varying property, and the speckle suppression effect is good.

The speckle suppression device provided by the invention has the advantages that through the use of the reflecting structure, the device has more possibility in spatial arrangement during integration.

The speckle suppression device has lower requirement on the position precision of the lens array forming the compound eye structure, and is more beneficial to large-scale production by using a mode with lower cost.

The speckle suppression device provided by the invention does not need to be matched with a vibrating projection screen for use, can realize a designed speckle suppression effect on a static screen, and improves the convenience and practicability of the system.

The speckle suppression device can be integrated in a display module of laser or other coherent light, suppresses the inherent speckle phenomenon in the coherent light display process, improves the resolution ratio of the display module, and is small in size and favorable for being integrated in an original laser display system.

The optical integrator of the speckle suppression device can be manufactured by the traditional manufacturing process, such as photoetching, etching and the like, and can also be manufactured repeatedly with stable process in a low-cost and high-yield mode by a nano-imprinting technology and a nano-printing technology.

When the device works, after collimated laser beams generated by a coherent light source (such as a laser) are incident to the speckle suppression device, the collimated laser beams transmit and form beams with the size in a certain range, which are formed by a plurality of sub-beams, and the beams are reflected into scanning beams by an MEMS micro-mirror device in a module, the sub-beams forming the scanning beams respectively form speckle patterns with smaller energy when the projection surface images, the speckle pattern effects with smaller energy are mutually overlapped, the overall effect of speckles is homogenized, the brightness is weakened, and the speckles appearing during imaging are suppressed.

The optical integrator belongs to a fly-eye type optical integrator, and a fly-eye structure of the optical integrator is composed of a cylindrical lens array which is orthogonally arranged, a group of cylindrical lens arrays which are orthogonally arranged have the same effect as a traditional micro lens array, and two groups of cylindrical lens arrays which are orthogonally arranged have the same effect as a traditional micro lens array pair.

The fly-eye structure of the optical integrator is composed of a Fresnel lens array. An array of fresnel lenses is in equivalent relationship to a conventional array of microlenses. The optical integrator can be freely matched and combined to form a compound eye structure in the compound eye type optical integrator, for example: 1 Fresnel lens array is matched with 1 micro lens array, 1 micro lens array is matched with 2 groups of columnar lens arrays which are orthogonally arranged, and the like. The specific arrangement of the lenticular lens array can also be changed.

The optical integrator can also be matched with optical elements such as a micro-lens array, a Fresnel lens array, a cylindrical lens array which is orthogonally arranged and the like through a reflecting device to form a compound eye structure of the optical integrator. The reflecting device may be statically fixed in the speckle suppression device or may be a MEMS micro-mirror device. Under MEMS actuation, the mirror (the galvanometer of the MEMS micro-mirror) can translate or rotate in/out of plane in one or more dimensions according to actual needs. According to actual requirements, various lens arrays for forming a fly-eye structure can be integrated on the surface of a reflector of the reflecting device, wherein the lens arrays comprise a micro lens array, a cylindrical lens array, a Fresnel lens array and the like. The reflecting device further includes a reflecting film plated on one main surface of the optical component.

The novel optical integrator of the speckle suppression device can be driven by a driving system, and at least one component in the optical integrator can move in at least one dimension, so that the incident angle/position of an incident laser beam is changed periodically, and a reflected beam formed by the MEMS micro-mirror device provided by the invention also has time-varying property, thereby further realizing speckle suppression.

Compared with the traditional micro-lens array type structure, the structure of the optical integrator is simpler and easier to process. The optical integrator and the speckle suppression device with the optical integrator can be realized by various existing mature manufacturing processes, specifically including but not limited to a traditional microlens processing process, a semiconductor processing process, a nano printing technology, a nano imprinting technology and the like, and the optical integrator and the speckle suppression device based on the optical integrator can be produced and manufactured in a large batch manner in a low-cost, high-yield and high-process-controllability manner. The optical integrator and the speckle suppression device with the optical integrator can also be used for more simply and freely designing and manufacturing a specific micro/nano structure pattern, even designing and manufacturing patterns which cannot be or are difficult to manufacture by a traditional method, such as a Fresnel lens array pattern and the like, and further reducing the size of the speckle suppression device within a cost controllable range.

The speckle suppression device can be integrated in a laser display module, high-efficiency laser speckle suppression is realized through a unique optical integrator, the optical integrator can also be integrated on an MEMS (micro-electromechanical system) micro-mirror, the optical integrator is driven by the drive of an MEMS system, and potential damage to other precise elements in the module when other drive devices are used for driving is avoided. Meanwhile, the speckle suppression device is simple in structure, small in size, low in power consumption, free of too much use condition limitation and high in speckle suppression effect, can be conveniently integrated in various coherent light scanning display modules, and can work in cooperation with other speckle suppression methods to achieve more effective speckle suppression.

The optical component is matched with the MEMS micro-mirror which can do in-plane/out-of-plane translation or rotation in at least one dimension, thereby realizing the same function as the compound eye structure in the traditional optical integrator. The galvanometer surface of the MEMS micromirror can be smooth or integrated with a lens array.

The optical integrator of the speckle suppression device can be driven by a driving system, and at least one component in the optical integrator can move in at least one dimension, so that the incident angle/position of an incident laser beam is changed periodically, and a reflected beam formed by the MEMS micro-mirror device also has time variation, thereby further realizing the speckle suppression.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.

Claims

1. An optical integrator, characterized by: the optical device comprises a first optical device and a second optical device in sequence from a light incidence side, wherein the first optical device and the second optical device are arranged in parallel,

the second optical device comprises a third main surface and a fourth main surface, the third main surface is a cylindrical lens array, the fourth main surface is a second reflecting layer, the third main surface is arranged opposite to the first main surface, and the cylindrical lens array of the third main surface and the cylindrical lens array of the first main surface are orthogonally arranged in a staggered mode;

2. An optical integrator in accordance with claim 1, wherein: the first reflecting layer is a reflecting mirror or a reflecting film; the second reflecting layer is any one of a reflecting mirror, a reflecting film or a MEMS micro-mirror,

the MEMS micro-mirror is capable of in-plane/out-of-plane translational or rotational motion in at least one dimension.

3. An optical integrator, characterized by: the optical device comprises a first optical device and a second optical device in sequence from a light incidence side, wherein the first optical device and the second optical device are arranged in parallel,

the first optical device comprises a first main surface and a second main surface, the first main surface and the second main surface are both lenticular lens arrays, and the lenticular lens array of the first main surface and the lenticular lens array of the second main surface are symmetrically arranged;

4. An optical integrator as claimed in claim 3, wherein: the second reflecting layer is any one of a reflecting mirror, a reflecting film or a MEMS micro-mirror,

5. An optical integrator, characterized by: the optical device comprises a first optical device and a second optical device in sequence from a light incidence side, wherein the first optical device and the second optical device are arranged in parallel,

the first optical device comprises a first main surface and a second main surface, the first main surface and the second main surface are both lenticular lens arrays, and the lenticular lens arrays of the first main surface and the lenticular lens arrays of the second main surface are arranged in a staggered mode;

the second optical device is a reflecting device;

6. An optical integrator as recited in claim 5, wherein: the distance between the second main surface and the reflecting device is half of the focal length of the cylindrical lens array of the second main surface;

the reflecting means is any one of a mirror, a reflective membrane or a MEMS micro-mirror capable of in-plane/out-of-plane translational or rotational motion in at least one dimension.

7. An optical integrator, characterized by: the optical device comprises a first optical device and a second optical device in sequence from a light incidence side, wherein the first optical device and the second optical device are arranged in parallel,

the first optical device includes a first principal surface and a second principal surface, both of which are lenticular lens arrays, and the lenticular lens array of the first principal surface and the lenticular lens array of the second principal surface are symmetrically arranged, the first principal surface and the second principal surface having a predetermined refractive power in a first direction within a plane orthogonal to an optical axis and having no refractive power in a second direction orthogonal to the first direction within the plane orthogonal to the optical axis,

the second optical device includes a third principal surface and a fourth principal surface, both of which are lenticular lens arrays, and the lenticular lens array of the third principal surface and the lenticular lens array of the fourth principal surface are symmetrically disposed, the third principal surface and the fourth principal surface having a predetermined refractive power in the second direction and no refractive power in the first direction,

the columnar lens array comprises a plurality of unit columnar lenses arranged side by side in an array;

alternatively, the first and second electrodes may be,

an optical integrator comprising, in order from a light incident side, a first optical device and a second optical device, the first optical device and the second optical device being arranged in parallel with each other,

the first and third main surfaces have a predetermined refractive power in a first direction within a plane orthogonal to an optical axis and have no refractive power in a second direction orthogonal to the first direction within the plane orthogonal to the optical axis; the second and fourth major faces having a predetermined refractive power in the second direction and no refractive power in the first direction,

8. A speckle reduction apparatus comprising the optical integrator of any of claims 1, 3 or 5, wherein: still include beam expander and first lens, beam expander, optical integrator and first lens set gradually along the light path, optical integrator is used for carrying out beam splitting and even bundle to coherent light, makes the speckle homogenization.

9. A laser display system comprising the speckle suppression apparatus of claim 8, wherein: also comprises a laser light source, a beam combiner and a micro-mirror device, wherein the laser light source, the beam combiner, the speckle suppression device and the micro-mirror device are arranged in sequence,

the laser light source is used for emitting laser beams of at least one color;

the beam combiner is used for forming the laser beam into combined beam light;

the micro-mirror device is used for reflecting the emergent light beam into a scanning light beam and projecting the scanning light beam to a projection surface for scanning display.

10. A laser display system comprising the speckle suppression apparatus of claim 8, wherein: also comprises a laser light source, a beam combiner and a micro-mirror device, wherein the laser light source, the beam combiner, the micro-mirror device and the speckle suppression device are arranged in sequence,

the laser light source is used for emitting laser beams of at least one color;

the beam combiner is used for forming the laser beam into combined beam light;

the speckle suppression device is used for expanding, splitting, homogenizing and converging the reflected light, generating a scanning light beam consisting of a plurality of sub-light beams, and projecting the scanning light beam to a projection surface for scanning and displaying.