CN106707671A

CN106707671A - Laser projection system

Info

Publication number: CN106707671A
Application number: CN201611242852.7A
Authority: CN
Inventors: 田有良; 李巍; 刘显荣
Original assignee: Hisense Group Co Ltd
Current assignee: Hisense Group Co Ltd
Priority date: 2016-12-29
Filing date: 2016-12-29
Publication date: 2017-05-24
Also published as: CN109884851A

Abstract

The invention discloses a laser projection system comprising a laser light source which emits laser beams of at least one color. The transmission light path of the laser beams includes a light homogenizing part which is used for receiving and homogenizing the laser beams; a light valve which is used for receiving the laser beams homogenized by the light homogenizing part and modulating the laser beams; a diffuse scattering phase plate which is arranged at the light incident surface side of the light homogenizing part and can increase the divergence angle of the beams; and a moving diffuser which is arranged at the light emergent surface side of the light homogenizing part and can greatly enhance the generation number of random phases, wherein the position of the moving diffuser is the object plane position of the light valve and the human eye integration effect is performed on the generated random phases so that the speckle effect of the projection frame can be weakened or eliminated to the greatest extent, and thus the speckle elimination effect and the display quality of the projection frame can be greatly enhanced.

Description

Laser projection system

Technical Field

The application relates to the field of projection display, in particular to a laser projection system.

Background

Laser is a light source with high brightness and strong directivity and emitting monochromatic coherent light beams, and a laser light source is an excellent coherent light source and has the advantages of good monochromaticity, strong directivity, high luminous flux and the like, and is gradually applied to the technical field of projection display as a light source in recent years.

The high coherence of laser also brings the speckle effect when laser projection shows, the speckle is that coherent light source is when shining rough object, the light after the scattering is because its wavelength is the same, the phase place is invariable, will produce the interference in the space, some parts take place to interfere constructively in the space, some parts take place to interfere destructively, final result is that the graininess is seen at screen light and shade alternate speckle, these unfocused speckles are in the scintillation state at people's eye looks, it is apt to produce dizzy uncomfortable to watch for a long time, more can cause the degradation of projection image quality, reduce user's viewing experience.

Therefore, the problem of reducing the speckle of the laser in the laser projection display process is a problem to be solved urgently at present.

Disclosure of Invention

The embodiment of the application provides a laser projection system, which is used for solving the technical problems of laser speckle and projection image degradation.

In order to realize the technical purpose, the following technical scheme is adopted:

a laser projection system comprising a laser light source emitting a laser beam of at least one color, characterized in that the laser beam also passes through, before entering a light valve: the dodging component is used for receiving and homogenizing the laser beam; the light valve is used for receiving the laser beam homogenized by the light homogenizing part and modulating the laser beam;

and a diffuse scattering phase plate disposed on the light incident surface side of the dodging member;

the moving diffuser is arranged on the light outlet side of the light homogenizing component, and the position of the moving diffuser is on the object surface of the light valve;

preferably, the diffusely scattering phase plate is a reflective phase plate and is translated in its reflective surface;

preferably, the reflective surface of the vibrating reflective phase plate is provided with a microstructure;

preferably, the diffuse scattering phase plate is a fixedly arranged phase plate, and the central area of the phase plate is larger than the divergence angle of the peripheral area to the laser beam;

preferably, the central region receives more than 50% of the laser beam energy;

preferably, the moving diffuser has a plurality of diffusing zones, the plurality of diffusing zones differing in angle of divergence to the light beam;

preferably, the moving diffuser transmits light beams, and the light incident surface and the light emergent surface of the diffuser are provided with diffusion microstructures;

preferably, the light unifying means comprises a light bar or a fly-eye lens array; the light valve is a DMD digital micromirror array chip;

preferably, the laser light source emitting the laser beam of at least one color includes: a laser emitting laser of a first color, a laser emitting laser of a second color, and a laser emitting laser of a third color; or,

the at least one light source includes: a laser emitting at least a first color laser, and a light source stimulated to produce at least a second color and a third color fluorescence; or,

the at least one light source includes: a laser emitting laser light of at least a first color and a second color, and a light source excited to produce fluorescence light of at least a third color;

preferably, the projection device further comprises a projection lens and a projection medium, wherein the projection lens is used for receiving the laser beam modulated by the light valve and projecting the laser beam to the projection medium to form a projection picture;

further, the first color is blue, the second color is green, and the third color is red.

The laser projection system provided by the technical scheme of the invention at least has the following beneficial effects:

in a laser projection system comprising a laser light source emitting a laser beam of at least one color, and prior to the laser beam being incident on a light valve comprising: the light source comprises a dodging component, a light valve, a diffuse scattering phase plate arranged on the light inlet side of the dodging component, and a moving diffuser arranged on the light outlet side of the dodging component, wherein the position of the moving diffuser is conjugate to the surface of the light valve.

On the one hand, through the light-emitting face side at the dodging part and for light valve object plane position department set up the diffuser of motion, firstly, the motion diffuser can carry out bigger degree diffusion in comparison with static diffusion part to the light beam, makes the angle of divergence of light beam diversified, does benefit to and produces a plurality of random phases, and the position that the motion diffuser place and light valve surface conjugate, then can regard as the object plane of light valve, the facula on the light valve forms the projection image after enlargiing through the magnification, thereby the position that the motion diffuser place also is conjugate each other with projection imaging surface. Therefore, the random phase distribution generated by the laser beam at the position can reflect the random phase distribution in the final formed projection image corresponding to the light valve to the maximum extent, and therefore, the random phase formed by the moving diffuser at the position influences the speckle homogenization degree generated by random phase integration in the final projection image to the maximum extent.

On the other hand, the diffuse scattering phase plate is arranged on the light incidence surface side of the dodging component, so that a plurality of divergence angles can be generated for the light beam, the diversity of the divergence angles of the light beam is formed, the diversity of the divergence angles brings about the change of the phase or the phase difference, and the diffuse scattering phase plate is favorable for destroying the interference condition and homogenizing the energy distribution of the laser beam to a certain degree.

In the transmission process of the laser beam, the diffuse scattering phase plate can enable the laser beam to form diversification of divergence angles for the laser beam before the laser beam enters the dodging component and the moving diffuser, and homogenize and change energy distribution, so that the efficiency of scattering a part of laser beam with strong coherence by the moving diffuser at the back is improved, and the part of laser beam is homogenized by certain energy, namely the moving diffuser diffuses the beam in a smaller light energy density unit or diffuses the relatively homogenized beam on the whole body, thereby improving the divergence degree of the beam on unit energy density, increasing diversification of divergence angles of the beam, and more easily generating a plurality of random phases.

The laser beam is homogenized and output by the light homogenizing component, and the vibrating reflection-type phase plate is arranged on the light incident surface side of the light homogenizing component, so that the light incident divergence angles are diversified, the divergence angles of the outgoing laser beam are diversified after the multiple divergence angles are homogenized, the homogenization degree of the laser beam is further improved, and the light homogenizing component is also beneficial to further generating a plurality of random phases by the moving diffuser.

In conclusion, the number of generated random phases can be greatly increased through the light path provided by the technical scheme of the invention, and the speckle effect of a projection picture can be weakened or eliminated through the integration effect of human eyes of the random phases, so that the speckle elimination effect and the display quality of the projection picture are greatly improved.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, 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 application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive exercise.

Fig. 1A is a schematic diagram illustrating an architecture of a laser projection system according to an embodiment of the present disclosure;

fig. 1B is a schematic diagram of another laser projection system according to an embodiment of the present disclosure;

fig. 1C is a schematic diagram of a structure of another laser projection system according to an embodiment of the present disclosure;

fig. 1D is a schematic diagram illustrating an architecture of another laser projection system according to an embodiment of the present disclosure;

fig. 2A is a schematic view of a moving direction of a vibration reflection type phase plate according to an embodiment of the present application;

fig. 2B is a schematic structural diagram of a vibration reflection type phase plate according to an embodiment of the present application;

FIG. 2C is a schematic cross-sectional view of a moving diffuser provided in an embodiment of the present application;

fig. 2D is a schematic plane sectional view of a phase plate according to an embodiment of the present disclosure;

FIG. 3 is a schematic diagram of a Gaussian energy distribution of a laser beam in the prior art;

FIG. 4 is a schematic diagram of a beam energy distribution for one aspect provided by an embodiment of the present application;

FIG. 5 is a schematic diagram of a beam energy distribution for yet another aspect provided by an embodiment of the present application;

fig. 6 is a schematic diagram of a beam energy distribution in another case provided by an embodiment of the present application.

Detailed Description

The embodiments of the present application will be described in detail below with reference to the accompanying drawings.

In the optical path of the laser transmission, there are often more optical lenses, which may generally include, for example: convex lens, concave-convex lens, dichroic mirror, collimating lens and other optical lenses. The light beam emitted by the laser is transmitted or reflected in each lens in the light path for optical processing.

In the laser transmission light path, a diffusion sheet or a rotating diffusion sheet is used for eliminating speckles, and the principle that the speckles are thinned by using a space superposition method and are superposed by using a time averaging method is mainly used. The speckle is thinned by splitting the light beam into a plurality of sub-light beams, the speckle patterns at different time points are superposed and homogenized, and the speckle phenomenon is diluted and weakened through the integration effect in human eyes.

In order to more clearly describe the technical solutions provided by the embodiments of the present application, the embodiments of the present application are described in detail below with reference to the accompanying drawings.

The first embodiment,

Referring to fig. 1A, an optical architecture of laser projection provided in the embodiment of the present application is schematically illustrated.

An optical architecture of a laser projection system provided in an embodiment of the present invention includes: the laser 101, the diffusely scattering phase plate 103, and in this example, a reflection-type phase plate that oscillates as a diffusely scattering phase plate, a condenser lens 102, a dodging member 104, a moving diffuser 105, a condenser lens 107, and a light valve 106 will be described.

The transmission path of the laser beam in the optical architecture shown in fig. 1A is as follows:

in the process of making the laser beam emitted from the laser 101 incident on the vibrating reflective phase plate 103, the laser beam emitted from the laser 101 usually needs some collimating or condensing components to form a small spot and then enters the vibrating reflective phase plate 103, which is not shown in fig. 1A.

The laser beam is reflected by the vibrating reflective phase plate 103, then is condensed and compressed by the condenser lens 102, the spot area is reduced, and the laser beam enters the dodging component 104, so that the light receiving efficiency of the dodging component 104 is improved, and the light beam with diversified divergence angles reflected by the vibrating reflective phase plate 103 is reflected for multiple times inside the dodging component 104 and is emitted from the light outlet of the dodging component 104.

The light beam emitted from the light exit of the dodging member 104 is transmitted and diffused by the moving diffuser 105, and then enters the focusing lens 107, and the focusing lens 107 condenses the diffused light beam. The converged light beam is finally incident to the light valve DMD 106.

Specifically, in the present optical path system, the laser 101 emits a laser beam as a laser light source. For simplicity, in this example, the laser group 101 emits laser beams of one color, which may be blue laser, red laser, or green laser.

The transmission light path of the laser beam comprises: the light homogenizing part 104 is used to receive and homogenize the laser beam emitted by the front end laser light source, and specifically may be a light rod, or a fly-eye lens array, in this example fig. 1A, the light rod is taken as an example, and the light rod may be a solid light rod or a hollow light rod, but the embodiment of the present invention does not specifically limit this.

In the DLP projection architecture, the light valve 106 is embodied as a DMD digital micromirror array chip, and the surface of the light valve 106 is an infinite number of tiny mirrors for receiving the illumination light beam and modulating the light beam according to the display driving signal. In the example of fig. 1A, only the dodging component 105 is shown to output the homogenized light beam and to be incident on the surface of the light valve 106, and in practical applications, since the light valve has strict requirements on the incident angle and size of the received illumination light beam, an illumination lens optical path, typically a plurality of lens components or mirrors, is usually further disposed between the dodging component 104 and the light valve 106, and in this example, only the ideal lens 107 is taken as an illustration.

Before the laser beam enters the dodging member 104, a reflective phase plate 103 is provided to vibrate, and specifically, the reflective phase plate is an optical element having a reflective surface and capable of finally changing the phase of the incident beam. Specifically, the present application relates to a reflection type phase plate that uses a vibration mirror to realize vibration, and the present application is not limited to a vibration mirror, and the present application does not specifically limit what component is used to realize the effect of the reflection type phase plate that uses vibration, as long as the component can make the divergence angle of the light beam diversified.

In the present example, the oscillating mirror 103 is disposed in the light entrance optical path of the light unifying member 104. The vibration reflector is driven by a driving part to vibrate at a certain high frequency, the vibration mode of the vibration reflector can be translational motion (translational motion refers to motion in a plane where the vibration reflector is located), the translational motion can be performed along one coordinate axis direction along a vertical coordinate system of the plane where the reflecting surface is located, or the translational motion can be performed along one coordinate axis direction firstly and then continuously performed along the other coordinate axis direction which is vertical to the one coordinate axis direction, and the two directions are performed alternately, as shown in fig. 2A. The vibration reflector changes the reflection angle of the light spot light beam in a translation mode, so that the positions of the light spots emitted at different moments are changed, in the light path shown in fig. 1A, the position of the laser beam incident to the focusing lens 102 is changed, the position of the light spot incident to the light uniformizing part 104 is changed, meanwhile, the divergence angle of the laser beam is increased, a certain homogenization effect is achieved on the light spots, and when the vibration of the vibration reflector reaches a certain frequency, the speckle effect is improved.

Preferably, the vibrating mirror surface has microstructures, as shown in fig. 2B, which can be randomly shaped without regularity.

The micro-structures with different granularities reflect the light beams differently when the vibrating reflector vibrates in a translation mode, so that diversified divergence angles can be formed, namely, the light beams enter the rugged micro-structures which change along with time, the translation motion of the vibrating reflector enables the micro-structures at the same spatial position of the reflectors at adjacent moments to be different, so that the light beams enter different micro-structure surfaces, the divergence angles are different when the light beams exit, and the phases are changed (the principle similar to a deformable reflector is that the concave-convex change of the surface of the deformable reflector is controlled by a program to randomly and disorderly change, so that the reflection of the light beams is disordered, and the diversity of the divergence angles is increased), the proportion of energy of the beam portion originally concentrated near the 0-degree optical axis is reduced, and the proportion of energy occupied by the diversified divergence angles is increased, so that the original Gaussian energy distribution is balanced to a certain extent.

The laser beam homogenized and emitted by the light homogenizing member 104 also passes through a moving diffuser 105 disposed on the light emitting surface side of the light homogenizing member 104, and the moving diffuser 105 may specifically be a moving diffuser, and the moving manner of the moving diffuser is not specifically limited, and may be a rotating movement, or a vibrating or swinging movement. In this example, the motion diffuser 105 is a transmissive diffuser. The position of the moving diffuser 105 is conjugate to the surface image plane of the light valve 106, and is also conjugate to the projection imaging plane, that is, the light beam spot received by the light valve 106 and the light spot at the position of the moving diffuser 105 are in an image-object relationship, and since the light valve 106 modulates the light beam, a picture with a magnification factor is finally formed on the projection medium, the position of the moving diffuser 105 is conjugate to the final projection imaging plane.

In this example, the moving diffuser 105 is a transmission-type component, and preferably, the diffusing microstructures may be disposed on both the light incident surface and the light emergent surface, as shown in fig. 2C, a schematic structural diagram of a cross section of the moving diffuser provides a schematic configuration of two microstructures, where the microstructures may be a plurality of saw-tooth-shaped protrusions, or circular protrusions, or other irregular patterns, and are not specifically limited herein, and the microstructures are used to scatter incident laser light, and since the reflecting surface is a non-planar surface, the angles and directions of the reflected laser light beams are diversified, so that a plurality of random spatial phases are formed, and coherence of the laser light beams is reduced. The microstructure shapes on both faces may be the same or different. And when the microstructures of the two surfaces are specifically arranged, the granularity can be different, so that two different scattering surfaces are formed, in practical application, the larger the scattering/diffusion difference of the two scattering surfaces to light beams is, the better the diversity of the divergence angles of the light beams is, and a plurality of random phases are generated.

And, the moving diffuser 105 may also have a plurality of diffusing zones, for example, may include a plurality of zones of diffusing zones a, b, c, which may have different divergence angles to the light beam, or any zone may be different from other zones. Especially, when the moving diffuser 105 sequentially transmits a plurality of laser beams, the moving diffuser can be matched with the rotation time sequence of the moving diffuser and the lighting time sequence of the plurality of laser beams, so that the laser beams with different colors can be incident into different diffusion subareas, such as blue laser and red laser, and the human eye is more sensitive to the speckle phenomenon caused by the red laser, therefore, the diffusion subarea b with a larger incident divergence angle of the red laser and the diffusion subarea a with a smaller incident divergence angle of the blue laser can balance the speckle effect of the two laser beams in the human eye. The diffusion partition arrangement for the moving diffuser 105 is not limited to 3 partitions, but may be 2 partitions, or no partitions.

The moving diffuser 105 is disposed at a conjugate position of an imaging plane of the light valve 106, specifically, the position of the moving diffuser is conjugate to the position of a finally viewed image plane, and in optical imaging, the conjugate refers to two points where an object side and an image side have a one-to-one mapping relationship: and points Q and Q ', if a light source is placed at the point Q, imaging is carried out at the point Q' and vice versa according to the principle of reversible light paths. The two points corresponding to each other are called a pair of conjugate points, the conjugate points can form conjugate lines and further have conjugate surfaces, so that the position of the moving diffuser can be called an object surface position, the finally seen image surface can be called an image surface position, specifically, the image surface can be called an object surface of a light valve surface (an intermediate imaging surface), and the light valve surface forms a projection imaging surface after being amplified by a magnification, so that the position of the moving diffuser, the light valve surface and the projection imaging surface are conjugate with each other. Due to the corresponding relation between the object plane and the image plane, the degree of association between the object plane and the image plane is larger than that between the object plane or the image plane and other positions in the optical path. Thus, if the beam is changed in the object plane, it is affected almost to the maximum extent for the image plane.

In the present example, the light beam is scattered and diffused by the moving diffuser at the position of the object plane, firstly, the moving diffuser can diffuse the light beam to a greater extent than the stationary diffusing part, so that the divergence angle of the light beam is diversified, and a plurality of random phases are generated, and the position of the moving diffuser is the position of the object plane of the light valve, and the random phase distribution generated by the laser beam at the position can reflect the random phase distribution in the final projection image corresponding to the light valve to the maximum extent, so that the random phase formed by the moving diffuser at the position can influence the speckle homogenization degree generated by the random phase integration in the final projection image to the maximum extent. When the moving diffuser diffuses the light beams to a certain degree to generate a plurality of random phases, the number of the random phases is increased in light spots formed at corresponding image surface positions, and speckle patterns at the position of a projection picture are thinned and the speckle phenomenon is weakened by utilizing the human eye integration effect and the superposition of the plurality of random phases.

In the embodiment of the present application, the moving diffuser 105 is disposed at the object plane position of the DMD imaging surface of the light valve 106, and the phase averaging effect at this position affects the imaging surface of the image to a large extent, so as to weaken the speckle eliminating effect to a large extent. The object plane position has a magnification relation with the final imaging plane, the smaller the magnification, the smaller the speckle particles after the homogenization effect of the rotating diffusion sheet is average, the better the phase averaging effect is, and the better the final speckle eliminating effect is. Therefore, it is desirable that the size of the light spot emitted from the light bar and the size of the irradiation beam spot required for the imaging surface be small in multiple.

In this example, motion diffuser 105 may specifically be a transmissive rotating diffuser.

In this example, the oscillating mirror 103 reflects the incident laser beam by using a plane having a microstructure and a translational oscillation manner, so that diversity of divergence angles of the laser beam is greatly increased, the diversity of the divergence angles brings different optical path differences, the different optical path differences lead to different phase differences, and the condition of generating interference by destruction is utilized. Meanwhile, the angle is changed from the energy distribution of the laser beam, the concentration degree of the energy distribution of the laser beam can be weakened, so that the energy distribution is homogenized from a peak type near the 0-degree optical axis to two sides of a plurality of divergence angles, the energy proportion of a beam part near the 0-degree optical axis with stronger coherence is reduced, and the energy distribution of the laser beam is homogenized to a certain degree.

At this time, the laser beam after being homogenized to a certain degree enters the light rod 104, so that the homogenization effect of the light beam entering the light rod 104 can be improved, the homogenization effect not only can make the chromaticity of light spots of the light beam uniform or make the color cast phenomenon of the light spots of the light beam uniform, but also can change the energy distribution rule of the laser beam.

Through the matching arrangement of the vibration reflecting mirror 103 and the rotary diffusion sheet 105 in the light path, the laser beam is subjected to energy distribution homogenization change before entering the dodging component and the moving diffuser, so that the scattering efficiency of the moving diffuser behind on a part of laser beam with strong coherence is improved, because the part of laser beam is subjected to certain energy homogenization, namely the moving diffuser, namely the rotary diffusion sheet 105 diffuses the beam in a smaller light energy density unit or diffuses the beam which is relatively homogenized on the whole, the light beam scattering degree in unit energy density is improved, the light beam scattering angle diversification is improved, and a plurality of random phases are generated more easily.

Based on the optical path architecture shown in fig. 1A, the laser beam emitted by the laser group passes through the vibrating reflective phase plate before entering the dodging component, and can rapidly change the reflection angle of the incident beam through the high-frequency vibration, so as to form the diversity of the divergence angles of the beam, and bring the change of the phase or the phase difference, which can be beneficial to destroying the interference condition, and can also homogenize the energy distribution of the laser beam to a certain degree, further, after the homogenization of the dodging component, the number of independent speckle images formed on the projection picture can be influenced to the maximum extent through the rotating diffusion plate arranged at the position of the light valve object plane.

The energy distribution change of the laser beam in the optical path transmission process shown in fig. 1A will be described in detail below with reference to the accompanying drawings.

Referring to fig. 3 to 6, the distribution of energy of the laser beam after passing through different optical components is schematically illustrated. In fig. 3 to 5, the X-axis represents the divergence angle of the light beam, and the Y-axis represents the energy ratio of the light beam.

As shown in fig. 3, which schematically shows the distribution of gaussian energy before the laser beam enters the oscillating mirror 103 shown in fig. 1A, it can be seen from fig. 3 that the gaussian energy of the laser beam is mainly concentrated on the 0-degree optical axis before passing through the oscillating mirror 103.

As shown in fig. 4, which schematically shows the energy distribution of the laser beam after passing through the vibrating mirror 103 shown in fig. 1A, it can be seen from fig. 4 that the gaussian energy at and around the 0-degree optical axis is attenuated compared to fig. 3. The energy distribution of the laser beam tends to be a relatively gentle flat-top energy distribution characteristic from the relatively concentrated peak-type distribution, and a plurality of small peaks appear at the edge part due to the increase of the divergence angle, because the laser beam part with strong spatial coherence is scattered and dispersed to the positions of various divergence angles, the energy ratio of the edge part in the graph is improved.

As shown in fig. 5, which schematically shows the energy distribution of the laser beam after passing through the light bar 104 shown in fig. 1A, it can be seen from fig. 5 that the divergence angle of the laser beam is increased due to the diffusion effect of the vibrating mirror 103, and after passing through the light bar 104, the beam is reflected multiple times inside the light bar 104, so that the beam is homogenized at multiple divergence angles, and thus the exit angle of the laser beam becomes diversified, which improves the effect of beam homogenization compared to the case where no diffusion sheet is provided on the light entrance surface side. Therefore, the energy distribution of the laser beam shown in fig. 5 is more uniform than that shown in fig. 4.

As shown in fig. 6, a schematic diagram exemplarily showing gaussian energy distribution of a laser beam after the laser beam passes through the transmission type rotating diffuser 105 shown in fig. 1A is shown, and as can be seen from fig. 6, after the laser beam passes through the rotating diffuser, the diversity of angles deviating from the optical axis of 0 degree is increased, so that the energy of the laser beam is redistributed among a plurality of divergence angles, and thus the energy distribution schematic diagram shown in fig. 6 is finally obtained, compared with the energy distribution schematic diagrams shown in fig. 3 to 5, the peak of gaussian energy of the laser beam shown in fig. 6 disappears, and tends to be distributed in a flat top shape, even approximately rectangular shape, i.e., the energy distribution is relatively balanced between the plurality of divergence angles and the optical axis of 0 degree, and this distribution causes the stronger optical beam energy ratio of the optical axis of 0 degree to be greatly reduced, which directly results in the reduction of.

In the laser light source shown in fig. 1A, the light source may be a laser, and of course, the light source may be a laser and a fluorescent light source, or a laser and a light emitting diode LED. In a specific implementation, the light source may include: the laser device may be a laser device that emits laser light of a first color, a laser device that emits laser light of a second color, and a laser device that emits laser light of a third color, or may be a laser device that emits laser light of at least the first color, and a light source that is excited to generate fluorescence of at least the second color and the third color, or may be a laser device that emits laser light of at least the first color and the second color, and a light source that is excited to generate fluorescence of at least the third color, where the first color may be blue, the second color may be green, and the third color may be red.

In some embodiments, the rotating diffuser is used to realize the phase-changing effect of the moving diffuser, but is not limited to the rotating diffuser, and the embodiment of the present invention is not limited to what component is used to realize the phase-changing effect in what moving manner, as long as the phase of the light beam can be changed.

Example II,

Different from the first embodiment, in the present example, the diffuse scattering phase plate is a fixedly arranged phase plate, and the diffusing plate is provided with partitions, and different partitions have different divergence angles for the laser beam.

Specifically, referring to fig. 1B, an optical architecture diagram of laser projection provided in the embodiment of the present application is shown. The optical structure includes: a laser group 101, a focusing lens 102, a fixed phase plate 103, a dodging component 104, a moving diffuser 105, and a light valve 106.

Specifically, the laser group 101 emits laser beams of at least one color, and for simplicity, in this example, the laser group 101 emits laser beams of one color, which may be blue laser, red laser, or green laser.

The laser beam spot size emitted by the laser group is usually large, and in order to improve the optical utilization rate of the following optical components, it is usually necessary to perform beam-shrinking and converging on the beam, in fig. 1B, the focusing lens 102 is an ideal lens, and the beam is converged only for the exemplary illustration, and in the practical product application, it may be a beam-shrinking and shaping system composed of multiple groups of lenses.

In this example, the arrangement of the light uniformizing element 104, the light valve 106, and the moving diffuser 105 can be referred to as embodiment one, and will not be described herein.

The laser beam also passes through the fixed phase plate 103 between the incident dodging member 104, and in this example, the fixed phase plate 103 is a transmission type phase plate and is disposed on the light incident surface side of the dodging member 104, and the phase plate may specifically be a diffusion plate.

In the example of fig. 1B, the transmission path of the laser beam in the above-described optical architecture is as follows:

the laser beam emitted from the laser group 101 is converged by the focusing lens 102, enters the fixed phase plate 103 in a converged state, is diffused and transmitted by the fixed phase plate 103, enters the optical rod 104, and is emitted from the light outlet of the optical rod 104 through multiple reflection inside the optical rod 104.

The light beam emitted from the light exit of the light stick 104 is transmitted and diffused by the moving diffuser 105, and then enters the focusing lens 107, and the focusing lens 107 converges the diffused light beam. The converged light beam is finally incident to the light valve DMD 106.

In the present example, the fixed phase plate 103 has different diffusion sections, specifically two large sections including a central region and a peripheral region, as shown in fig. 2D. The divergence angle of the central area to the laser beam is larger than that of the peripheral area to the laser beam. In a specific implementation, the diffusion microstructures may be provided in the central region and not provided in the peripheral region. Or the granularity of the diffusion microstructure arranged in the central area is smaller than that of the diffusion microstructure arranged in the peripheral area, so that the granularity of the diffusion microstructure in the central area is denser and the divergence degree of the laser beam is stronger, for example, the divergence angle of the central area to the laser beam is more than 1.5 times of that of the peripheral area to the laser beam.

The fixed phase plate 103 may be a disc or a square, and thus the shapes of the central area and the peripheral area thereof may be divided according to the specific shape of the phase plate.

When the laser beam is divided, the central area receives more than 50% of the energy of the laser beam spot, so that the energy near the 0-degree optical axis of the laser beam is concentrated and occupies a large area according to the Gaussian distribution characteristics of the laser beam, and the area of the central area serving as a processing area of the beam part with concentrated laser beam energy needs to be set to be more than 50% capable of receiving the laser beam spot energy according to the distribution condition of the beam.

Similar to the embodiment, in this example, the light beam is scattered and diffused by the moving diffuser at the position of the object plane, first, the moving diffuser can diffuse the light beam to a greater extent than the stationary diffusing part, so that the divergence angle of the light beam is diversified, and a plurality of random phases are generated, and the position of the moving diffuser is the position of the object plane of the light valve, where the random phase distribution generated by the laser beam can reflect the random phase distribution in the final projection image corresponding to the light valve to the maximum extent, so that the random phase generated by the moving diffuser at the position influences the speckle homogenization degree generated by the random phase integration in the final projection image to the maximum extent. When the moving diffuser diffuses the light beams to a certain degree to generate a plurality of random phases, the number of the random phases is increased in light spots formed at corresponding image surface positions, and speckle patterns at the position of a projection picture are thinned and the speckle phenomenon is weakened by utilizing the human eye integration effect and the superposition of the plurality of random phases.

Meanwhile, in this example, the fixed phase plate 103 is provided in front of the optical rod 104, and a diffusion plate is taken as an example for description.

Since the fixed diffusion sheet 103 is divided into a central region and a peripheral region, and the central region has a higher divergence degree for the laser beam than the peripheral region, a portion where the energy of the laser beam is concentrated can be diverged to a greater degree, so that the portion of the laser beam is scattered to the edge, and the light with the smaller relative energy ratio at the edge is scattered to a smaller extent or is not scattered, so that the energy distribution of the laser beam tends to a flat-top type relatively mild distribution rule from a peak type distribution, and the energy distribution of the laser beam can be homogenized to a certain extent.

Through the arrangement of the fixed diffusion sheet 103 and the rotary diffusion sheet 105, the laser beam is subjected to energy distribution homogenization change before entering the dodging component and the moving diffuser, so that the efficiency of scattering a part of laser beam with stronger coherence by the moving diffuser behind is improved, because the part of laser beam is subjected to certain energy homogenization, namely the moving diffuser diffuses the beam in a smaller light energy density unit or diffuses the relatively homogenized beam on the whole, the divergence degree of the beam in unit energy density is improved, the divergence angle of the beam is diversified, and a plurality of random phases are more easily generated.

For the light path architecture provided in this embodiment, the energy distribution change of the laser beam when passing through the fixed diffuser, the light uniformizing element, and the moving diffuser can also be referred to the descriptions of fig. 3 to 6 in the first embodiment, and the principle of the two embodiments is the same, and is not described herein again.

Based on the optical path architecture shown in fig. 1B, the laser beam emitted by the laser group passes through a fixed diffusion sheet before entering the light uniformizing component, the divergence angle of the central area of the fixed diffusion sheet to the laser beam is larger than that of the peripheral area to the laser beam, the energy distribution of the laser beam can be improved in a targeted and efficient manner, the energy proportion of the beam which is near the 0-degree optical axis with strong spatial coherence and has larger energy proportion is weakened, and further, after the homogenization by the light homogenizing part, then the number of independent speckle images formed on the projection picture can be influenced to the maximum extent through the rotary diffusion sheet arranged at the position of the object plane of the light valve, under the action of the fixed diffusion sheet and the rotating diffusion sheet in the scheme, a plurality of random phases can be generated under the action of superposition, so that the speckle effect in a projection picture is greatly reduced after the integral action of human eyes.

Example III,

In the present embodiment, the diffuse scattering phase plate may be specifically two types, that is, the scheme shown in fig. 1C is obtained in the basic modification of the combination of the first embodiment and the second embodiment. Specifically, on the basis of fig. 1A, the diffuse scattering phase plate may be a vibrating mirror 103, and a first phase plate 108 is further disposed between the vibrating mirror 103 and the light inlet of the optical wand 104. In the present example, the first phase plate 108 may specifically be a transmission type phase plate, and is fixedly disposed. The arrangement of the first phase plate 108 can be referred to the description of fig. 1B in the second embodiment.

In the laser projection system shown in fig. 1C, the method specifically includes: the laser device 101a, the laser device 101b and the laser device 101c respectively emit laser beams, and the laser beams emitted by the laser devices are combined through the two light combining lenses to form a beam of light output, wherein the first light combining lens 102a and the second light combining lens 102 b. In practical applications, the lasers 101a, 101b, and 101c may specifically be a blue laser 101a, a red laser 101b, and a green laser 101c, the first light combining lens 102a may specifically be a dichroic plate 102a, and the second light combining lens 102b may specifically be a second dichroic plate 102 b.

The combined light of the blue laser light, the green laser light, and the red laser light is made into one beam, and then enters the reflection surface of the oscillating mirror 103, and enters the condenser lens 102 after being reflected, enters the transmission type fixed diffusion sheet 108 in a condensed state after being condensed by the condenser lens 102, enters the dodging member 104 after being diffused by the transmission type fixed diffusion sheet 108, exits from the transmission type rotating diffusion sheet 105 after being reflected for a plurality of times inside the dodging member 104, and enters the light valve DMD106 through the condensing action of the condenser lens 107 after exiting from the transmission type rotating diffusion sheet 105. An illumination system (not shown in the figure) in front of the light valve DMD106 directs the light beam to the surface of the light valve DMD106, which consists of thousands of small mirrors that reflect the light beam into a projection lens 109 to image (in this example, the projection lens is represented by an ideal lens 109 only) and project it to a projection medium 110 to form a projected image.

In this example, the light beam reflected by the vibrating mirror 103 has an angle diversity, and the light beam incident to the transmission type fixed diffusion sheet 108 is further homogenized, because the divergence angle of the central area of the fixed diffusion sheet 108 to the laser beam is greater than the divergence angle of the peripheral area to the laser beam, the light beam energy proportion near the 0-degree optical axis with strong coherence in the laser beam can be further weakened, so that the homogenization effect of the light beam is improved in an auxiliary manner, and meanwhile, the light beam is further diffused well by matching with the rotating diffusion sheet on the light-emitting surface of the light homogenizing component, so that the number or probability of generating random independent phases is increased, so that a plurality of different independent speckle images are formed, and after human eye integration, the speckle effect is weakened.

The oscillating mirror 103 shown in fig. 1B is disposed on the transmission path of the incident light beam of the transmission type fixed diffusion sheet 108, but of course, the oscillating mirror 103 may also be disposed on the transmission path of the emergent light beam of the transmission type fixed diffusion sheet 108, and the effect of homogenization can be achieved as well, and the embodiment of the present invention does not specifically limit this.

If the oscillating mirror 103 is disposed on the transmission path of the outgoing light beam of the transmission type fixed diffusion sheet 108, the light uniformizing part 104 is preferably a fly eye lens array so as to receive the incoming light beam of a large divergence angle. The fly-eye lens array is formed by arranging two lines of fly-eye lens arrays in parallel, the focus of each small unit lens in the first line of fly-eye lens array is superposed with the center of the corresponding small unit lens in the second line of fly-eye lens array, the optical axes of the two lines of fly-eye lenses are parallel to each other, a condenser lens is arranged behind the second line of fly-eye lens array, and the focal plane of the condenser lens is used for placing an illumination screen to form an illumination system which can receive incident light beams with large divergence angles.

Alternatively, based on the modification of the optical structure shown in fig. 1C, as shown in fig. 1D, a second phase plate 111 may be disposed between the light uniformizing member 104 and the rotating diffusion plate 105, specifically, the second phase plate may be a transmissive diffusion plate, which can diffuse the light beam emitted from the light rod 104 again to change the phase distribution, so as to further homogenize the light beam, and the light beam diffused by the transmissive diffusion plate 111 passes through the transmissive rotating diffusion plate 105, so as to increase the probability that the rotating diffusion plate generates a random phase on the light beam, thereby being beneficial to reducing the speckle effect.

In the above scheme, the first phase plate 108 and the second phase plate 111 may be both fixedly disposed as described above, or the first phase plate 108 may be fixedly disposed, so as to ensure that the divergence angle of the light beam passing through the phase plates is not too large and exceeds the light receiving range of the optical rod 104, and the second phase plate 111 is movably disposed, and the movement manner thereof may be rotation, oscillation or vibration, which is not specifically limited herein.

In the optical structure shown in fig. 1B, 1C, and 1D, the fixed diffuser is a transmissive fixed diffuser, but the fixed diffuser may also be a reflective fixed diffuser, and only when the fixed diffuser is a reflective fixed diffuser, the position of the fixed diffuser needs to be adjusted so that the light beam reflected from the reflective fixed diffuser enters the light uniformizing member.

In summary, in the embodiments of the multiple laser projection systems provided by the technical solutions of the present invention, the diffuse scattering phase plate is disposed on the light incident surface side of the dodging component in the light path from the laser light source to the light valve to form diversity of divergence angles of the laser light beams, and the moving diffuser is disposed on the light exit surface side of the dodging component, so that the number of random phases of the laser light beams can be increased by superposition, and the degree of homogenization of energy distribution of the laser light beams can be improved, and since the moving diffuser is disposed at the position of the conjugate image plane of the projection image, the situation of independent speckle patterns of the projection image can be reflected to the greatest extent, that is, the random phase distribution generated by the moving diffuser directly affects the integral effect of the independent speckle images of the projection image, so that when the number of random phases generated by the moving diffuser is increased, the speckle effect of the projection image can be alleviated to the greatest, the speckle dissipation effect of the laser projection system is improved.

The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

While the preferred embodiments of the present application have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all alterations and modifications as fall within the scope of the application.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present application without departing from the spirit and scope of the application. Thus, if such modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is intended to include such modifications and variations as well.

Claims

1. A laser projection system comprising a laser light source emitting a laser beam of at least one color, wherein said laser beam is further passed through: a light homogenizing member for receiving and homogenizing the laser beam; the light valve is used for receiving the laser beam homogenized by the light homogenizing part and modulating the laser beam;

and the moving diffuser is arranged on the light outlet side of the light uniformizing component, and the position of the moving diffuser is conjugate to the light valve surface.

2. A laser projection system as claimed in claim 1, wherein the diffusely scattering phase plate is a reflective phase plate and is translatable in its reflective surface.

3. The laser projection system of claim 2, wherein the reflective surface of the oscillating reflective phase plate is provided with microstructures.

4. The laser projection system of claim 1, wherein the diffusely scattering phase plate is a fixedly disposed phase plate, and a central region of the phase plate is larger than a divergence angle of the peripheral region to the laser beam.

5. The laser projection system of claim 1, wherein the central region receives more than 50% of the energy of the laser beam.

6. The laser projection system as claimed in claim 1, wherein the moving diffuser transmits a light beam, and the light incident surface and the light exiting surface are each provided with a diffusing microstructure.

7. The laser projection system of claim 1, wherein the moving diffuser has a plurality of diffusing regions that diverge the light beam at different angles.

8. A laser projection system as claimed in claim 1 wherein the light unifying component comprises a light rod or a fly-eye lens array; the light valve is a DMD digital micromirror array chip.

9. The laser projection system as claimed in claim 1, wherein said laser light source emitting laser beams of at least one color comprises: a laser emitting laser of a first color, a laser emitting laser of a second color, and a laser emitting laser of a third color; or,

the at least one light source comprises: a laser emitting at least a first color laser, and a light source stimulated to produce at least a second color and a third color fluorescence; or,

the at least one light source comprises: a laser emitting laser light of at least a first color and a second color, and a light source excited to produce fluorescence light of at least a third color.

10. The laser projection system as claimed in claim 1 or 9, further comprising a projection lens and a projection medium, wherein the projection lens is configured to receive the laser beam modulated by the light valve and project the laser beam onto the projection medium to form a projection image.

11. The laser projection system of claim 9, wherein the first color is blue, the second color is green, and the third color is red.