CN112859497B

CN112859497B - Laser projection display system

Info

Publication number: CN112859497B
Application number: CN201911101404.9A
Authority: CN
Inventors: 余新; 张贤鹏; 胡飞; 吴超; 陈晨; 李屹
Original assignee: Appotronics Corp Ltd
Current assignee: Shenzhen Appotronics Corp Ltd
Priority date: 2019-11-12
Filing date: 2019-11-12
Publication date: 2023-07-14
Anticipated expiration: 2039-11-12
Also published as: WO2021093659A1; CN112859497A

Abstract

The invention provides a laser projection display system, which comprises a laser generator, a scattering sheet vibrating device and a projection imaging device. Wherein the laser generator is used for emitting laser. The scattering sheet vibrating device comprises a fluid channel, a scattering element and a vibrating driver, wherein the scattering element is arranged in the fluid channel in a vibrating way and is positioned in the optical path of laser, the vibrating driver is used for enabling fluid in the fluid channel to generate driving force acting on the scattering element, the scattering element vibrates under the action of the driving force, and the scattering element vibrates at least along the vertical direction of the incident laser. The projection imaging device is positioned on the light path of the laser and is used for modulating the laser emitted from the scattering element into image light and projecting the image light to the projection screen for imaging. The laser projection display system provided by the invention drives the scattering element to vibrate through the driving force generated by the fluid, and has the advantages of simple system and strong practicability.

Description

Laser projection display system

Technical Field

The invention relates to the technical field of optics, in particular to a laser projection display system.

Background

The laser has the characteristics of high brightness, good monochromaticity, strong directivity and the like, and the color gamut of the picture obtained when the laser is used as a projection light source is large, so that more true and rich colors can be displayed. However, due to the strong coherence of laser, speckle is generated during imaging, which reduces resolution of a picture and affects imaging quality. In order to solve the speckle problem, a few scientific researchers put into the device and put forward various methods for reducing the speckle contrast, such as using light sources with different wavelengths to reduce the coherence of the light sources, and such as vibrating a display chip, a projector, a projection screen, etc. to reduce the speckle contrast, but these vibration modes have certain technical difficulties, and a vibration driving device with a power component (such as an engine) needs to be added, which increases the complexity of the system, and the practicability is limited, so that the requirements of users are difficult to meet.

Disclosure of Invention

The present invention is directed to a laser projection display system to solve the above-mentioned problems.

The embodiment of the invention realizes the aim through the following technical scheme.

The invention provides a laser projection display system, comprising:

a laser generator for emitting laser light;

a diffusion sheet vibration device including a fluid passage, a diffusion element vibratably disposed within the fluid passage and positioned in an optical path of the laser light, and a vibration driver for generating a driving force acting on the diffusion element by the fluid within the fluid passage, the diffusion element vibrating under the driving force, the diffusion element vibrating at least in a vertical direction of the incident laser light; and

And the projection imaging device is positioned on the light path of the laser and used for modulating the laser emitted from the scattering element into image light and projecting the image light to a projection screen for imaging.

In one embodiment, the vibration driver is a vortex street generator, the vortex street generator is arranged in the fluid channel, and double-line vortex generated by the fluid passing through the vortex street generator is used as driving force for vibration of the scattering element.

In one embodiment, the angle between the normal of the scattering element and the incident laser light is greater than 0 ° and less than 90 °.

In one embodiment, the angle between the normal of the scattering element and the incident laser light is in the range of 45 ° to 60 °.

In one embodiment, the laser projection display system further comprises a heat dissipation channel in communication with the fluid channel, the fluid exiting the heat dissipation channel flowing into the fluid channel and acting on the vibration driver.

In one embodiment, the fluid channel comprises a first channel and a second channel into which fluid flows in sequence, the first channel having a cross-sectional dimension that gradually decreases along the direction of flow of the fluid, the vibration driver and the scattering element being located in the second channel.

In one embodiment, the vibration driver is located a set distance from the fluid inlet of the second channel.

In one embodiment, the axis of the vortex street generator is perpendicular to the normal of the scattering element and perpendicular to the axis of the fluid channel, the vortex street generator comprising an arc surface located on a side of the vortex street generator remote from the scattering element.

In one embodiment, the diffusion sheet vibration device further includes an elastic member, one end of which is connected to the diffusion element, and the other end of which is fixed to the inner wall of the fluid channel.

In one embodiment, the scattering element is quadrilateral, the number of the elastic pieces is four, each elastic piece is connected with one corner of the scattering element, or

The scattering element being circular, the number of elastic members being an even number, or

The scattering element is triangular, the number of the elastic pieces is three, or

The scattering element is hexagonal, and the number of the elastic pieces is three or six.

Compared with the prior art, the laser projection display system provided by the invention drives the scattering element to vibrate through the driving force generated by the fluid, the direct acting object of the vibration driver is the fluid instead of the projection component, and the driving force for driving vibration can be generated only by slightly guiding the fluid due to the flow characteristic of the fluid, so that the vibration driver has a simpler structure and does not need to be provided with a power component. The method for driving the fluid to vibrate not only achieves the purpose of reducing speckle contrast, but also does not increase the complexity of a projection display system, and has strong practicability.

These and other aspects of the invention will be more readily apparent from the following description of the embodiments.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the description of the embodiments will be briefly introduced below, it being obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic structural diagram of a laser projection display system according to an embodiment of the present invention.

Fig. 2 is a schematic structural diagram of a heat dissipation channel and a scattering sheet vibration device of a laser projection display system according to an embodiment of the present invention.

Fig. 3 is a schematic perspective view of a second channel of a laser projection display system, and a vibration plate, a vortex street generator and an elastic member disposed in the second channel according to an embodiment of the present invention.

Fig. 4 is a light path diagram of a laser projection display system according to an embodiment of the present invention.

Fig. 5 is a diagram showing a dual line vortex of a laser projection display system according to an embodiment of the present invention.

FIG. 6 is a flow rate simulation of a fluid within a fluid channel of a laser projection display system provided by an embodiment of the present invention.

FIG. 7 is a simulation of the turbulence of a fluid within a fluid channel of a laser projection display system provided by an embodiment of the present invention.

FIG. 8 is a cross-sectional view of a vortex street generator of a laser projection display system provided in accordance with an embodiment of the present invention.

FIG. 9 is a cross-sectional view of another vortex street generator of a laser projection display system according to an embodiment of the present invention

Detailed Description

In order to facilitate an understanding of the embodiments of the present invention, the embodiments of the present invention will be described more fully below with reference to the accompanying drawings. The drawings illustrate preferred embodiments of the invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein in the examples of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

Referring to fig. 1 and 2, a laser projection display system 1 provided by the present invention includes a laser generator 10, a diffusion sheet vibration device 20 and a projection imaging device 30. Wherein the laser generator 10 is for emitting laser light. The diffusion sheet vibration device 20 includes a fluid passage 21, a diffusion element 23, and a vibration driver 25, the diffusion element 23 being vibratably disposed in the fluid passage 21 and located in an optical path of the laser light, the vibration driver 25 being configured to cause the fluid in the fluid passage 21 to generate a driving force acting on the diffusion element 23, the diffusion element 23 vibrating under the driving force, the diffusion element 23 vibrating at least in a vertical direction of the incident laser light. The projection imaging device 30 is located on the optical path of the laser light, and is configured to modulate the laser light emitted from the scattering element 23 into image light, and project the image light to the projection screen 80 for imaging.

In a preferred embodiment, the vibration driver 25 is a vortex street generator, which is disposed in the fluid channel 21, and the double-line vortex (as shown in fig. 5) generated by the fluid passing through the vortex street generator is the driving force for the scattering element 23 to vibrate.

Specifically, in the present embodiment, the laser generator 10 is configured to emit laser light, the laser generator 10 includes a laser, and the laser generator 10 may be any one of the red laser generator 10, the blue laser generator 10, and the green laser generator 10. The laser generator 10 may comprise one or two lasers. The laser generator 10 may also be a laser array, i.e. comprising a plurality of lasers, each of which may be spaced apart from its adjacent lasers so that the light emitting surfaces of each of the lasers in the laser array together form a surface light source. The number of lasers can be selected according to actual needs. The laser may be a Laser Diode (LD) or a Light Emitting Diode (LED), etc.

Referring to fig. 2 and 3, the diffuser vibration device 20 is configured to vibrate the diffuser 23, and displace the diffuser 23 in a normal direction of the diffuser 23, so as to reduce the speckle contrast of the laser and improve the imaging quality of the laser projection display system 1.

In the present embodiment, the fluid passage 21 has a substantially hollow cylindrical shape, and the fluid passage 21 includes a first passage 213 and a second passage 215 into which fluid flows in sequence. The second channel 215 is a hollow cuboid, and the cross-sectional dimensions of the second channel 215 are constant values. In an alternative embodiment, the first channel 213 is a hollow quadrangular pyramid shape, and the cross-sectional dimension of the first channel 213 is gradually reduced in the flow direction of the fluid so that the fluid passing through the first channel 213 is accelerated, and as shown in fig. 6, the velocity of the fluid is gradually increased in the flow direction of the fluid. The first channel 213 may also reduce the turbulence of the fluid, as shown in fig. 7, which gradually decreases in the flow direction of the fluid.

In other alternative embodiments, the cross-sectional dimensions of both the first channel 213 and the second channel 215 may be fixed values and the same; or the cross-sectional dimension of the first channel 213 is fixed and smaller than the cross-sectional dimension of the second channel 215. In one embodiment, the first channel 213 is hollow circular truncated cone shape and the second channel 215 may be hollow cylindrical; the first channel 213 may be a hollow triangular pyramid shape, etc., and the second channel 215 may be a hollow triangular prism shape. The shape and cross-sectional dimensions of the fluid channel 21 may be designed according to the circumstances, as required to meet the requirements of creating karman vortex streets within the fluid channel 21.

As shown in fig. 3, the second channel 215 includes opposing fluid inlet 2152 and fluid outlet 2154, wherein the fluid inlet 2152 is in direct communication with the first channel 213, and fluid enters the second channel 215 through the fluid inlet 2152 and exits through the fluid outlet 2154 after exiting the first channel 213.

In this embodiment, the second channel 215 is located on the laser light path, and the second channel 215 is transparent corresponding to the structure of the laser light path, and other portions of the second channel 215 may also be transparent. The light transmittance of the structure corresponding to the laser light path may be selected according to the actual situation.

In other alternative embodiments, the fluid channels 21 may all be light transmissive structures, and the light transmittance of each portion of the fluid channels 21 may be the same or different.

Referring to fig. 2 and 4, the scattering element 23 may be a transmissive scattering element 23 or a reflective scattering element 23, and the vibration of the scattering element 23 makes the transmitted (reflected) light phase difference different, so as to generate different speckles, and these different speckles overlap during the integration time of human eyes to reduce the speckle contrast.

The scattering element 23 is vibratably disposed within the fluid channel 21 in the optical path of the laser light, the scattering element 23 being vibrated by the double line vortex, the scattering element 23 being vibrated at least in the vertical direction of the incident laser light. In order for the vibration of the scattering element 23 to effectively eliminate the coherence of the laser light, the normal direction D of the scattering element 23 needs to have a set angle α with the direction of the incident laser light, in which case the vibration of the scattering element 23 in the normal direction D of the scattering element 23 can decompose the vibration perpendicular to the direction of the incident laser light, which is an effective vibration, the coherence of the laser light can be reduced to some extent, and thus the speckle contrast can be reduced. In the present embodiment, the angle α between the normal direction D of the scattering element 23 and the incident laser light is greater than 0 ° and less than 90 °. Specifically, the angle α between the normal D of the scattering element 23 and the optical path of the laser light may be in the range of 45 ° to 60 °. When the angle α between the normal direction D of the scattering element 23 and the optical path of the laser is smaller than 45 degrees, the spot size on the scattering element 23 increases gradually, which affects the imaging quality of the laser projection display system 1. When the angle α between the normal direction D of the scattering element 23 and the optical path of the laser is greater than 60 degrees, the effect of reducing speckle is limited. Therefore, in practical operation, in order to achieve both of the imaging quality and the effect of reducing the speckle, it is generally recommended that the angle α between the normal D of the scattering element 23 and the optical path of the laser light be in the range of 45 ° to 60 °. However, in other alternative embodiments, the angle α between the normal D of the scattering element 23 and the optical path of the laser may be set to other angles according to practical needs, for example, the angle may be 15 ° -75 °.

With continued reference to fig. 2, in this embodiment, the scattering sheet vibrating device 20 further includes an elastic member 40, and the elastic member 40 may be used to fix the scattering element 23 on one hand, and may also convert the pressure of the fluid into the displacement of the scattering element 23 on the other hand. One end of each elastic member 40 is connected to the scattering element 23, and the other end is fixed to the inner wall of the fluid passage 21. The elastic member 40 may be a spring having a small elastic coefficient to resonate, so that the vibration displacement of the scattering element 23 is greatly increased and speckle contrast is significantly reduced. The scattering element 23 is disposed in the second channel 215, specifically, the scattering element 23 is vibratably disposed in the fluid channel 21, the scattering element 23 is quadrilateral, the number of the elastic members 40 is four, and each elastic member 40 is connected to one corner of the scattering element 23.

In other embodiments, the scattering element 23 may also be circular, triangular, hexagonal, etc. in shape. The number of the elastic members 40 may be two, three or more, the positions of the elastic members 40 may be distributed in other forms, for example, the scattering element 23 may be quadrangular, the number of the elastic members 40 may be two, and the two elastic members 40 connect opposite sides of the scattering element 23 to dispose the scattering element 23 in the second channel 215. For another example, the scattering element 23 may be circular, and the number of the elastic members 40 may be two, where one elastic member 40 may be connected to one inner wall of the scattering element 23 and the second channel 215, and the other elastic member 40 may be disposed at a distance from the other inner wall of the scattering element 23 and the second channel 215. For another example, the scattering element 23 has a triangular shape, and the number of elastic members 40 is three. For example, the scattering element 23 is hexagonal, and the number of elastic members 40 is three or six. Those skilled in the art will appreciate that the number of elastic members 40, the shape of the scattering element 23, and the manner in which the scattering element 23 is disposed in the second channel 215 may take many other forms.

In this embodiment, the vortex street generator is cylindrical, and the vortex street generator is used to generate a driving force for the fluid in the fluid channel 21 to act on the scattering element 23, so as to reduce speckle contrast. In particular, a vortex street generator may be used to form karman vortex streets. The principle of the vortex street generator for generating karman vortex street is as follows: the vortex street generator is used as disturbing fluid, and when the steady fluid bypasses the surface of the vortex street generator, two sides of the vortex street generator periodically drop out double-row line vortices with opposite rotation directions and regular arrangement, so that a karman vortex street is formed.

The vortex street generator may comprise a curved surface and the curved surface is located on the side of the vortex street generator remote from the scattering element 23, the cross section of the vortex street generator may be circular or annular (as shown in figure 8), in this embodiment the vortex street generator may be a cylinder with a diameter of 2 mm. The size of the vortex street generator is specifically set based on the size of the fluid passage and the amount of driving force to be generated.

Referring to fig. 9, in other embodiments, the vortex street generator may further include a plane connected to the arc surface, and the cross section of the vortex street generator may be semicircular or semi-annular. In other embodiments, the vortex street generator may have other shapes, such as elliptical, square, etc.

With continued reference to fig. 2 and 4, the vibration driver 25 is disposed within the fluid channel 21 and adjacent to the scattering element 23, in particular, the vibration driver 25 is disposed within the second channel 215, and the vibration driver 25 is adjacent to the first channel 213 with respect to the scattering element 23. The vibration driver 25 is located between the fluid inlet 2152 and the fluid outlet 2154, i.e. the vibration driver 25 is located at a set distance from the fluid inlet 2152 of the second channel 215, so that the inlet effect of the fluid is reduced, the turbulence is further reduced, and the condition of the steady fluid is satisfied.

The axis of the vortex street generator is perpendicular to the normal D of the scattering element 23 and to the axis of the fluid channel 21.

With continued reference to fig. 1 and 2, the projection imaging device 30 is located on the optical path of the laser light, and is configured to modulate the laser light emitted from the scattering element 23 into image light, and project the image light onto the projection screen 80 for imaging. The projection imaging apparatus 30 may include optics such as a color wheel, spatial light modulator, lens, etc.

The laser projection display system 1 further comprises a heat dissipation channel 50, which heat dissipation channel 50 may be used to reduce the temperature of the various elements of the laser projection display system 1. Specifically, the working temperature of the components such as the laser generator 10 is high, and the heat emitted by the heating components such as the laser generator 10 can be emitted to the external environment through the heat dissipation channel 50. Generally, the heat dissipation channel 50 dissipates heat from a heat generating element such as the laser generator 10 by air flow, that is, wind. Air is also a fluid and may also be used to create karman vortex streets. Thus, in one embodiment, the heat dissipation channel 50 communicates with the fluid channel 21, in particular, the heat dissipation channel 50 communicates with the first channel 213, and the fluid exiting the heat dissipation channel 50 flows into the fluid channel 21 and acts on the vibration driver 25. The fluid passes through the vibration driver 25 so that the scattering element 23 vibrates.

The laser projection display system 1 further comprises a converging lens 60, the converging lens 60 being located between the laser generator 10 and the diffusion sheet vibrating device 20, the focal point of the converging lens 60 being located on the diffusion element 23, so that the light incident on the diffusion element 23 is more concentrated.

The laser projection display system 1 further comprises a collimator lens 70 and a projection screen 80, the collimator lens 70 being located between the diffuser vibration device 20 and the projection imaging device 30. The collimator lens 70 is used for collimating the laser light. The projection imaging apparatus 30 is positioned between the collimating lens 70 and the projection screen 80, and the projection screen 80 may be an LED display screen or the like.

The following is a working principle for reducing speckle contrast of the laser projection display system 1 provided by the invention:

the heat emitted from the laser generator 10 and other elements having larger heat generation amounts passes through the heat dissipation channel 50 to form an air flow and flows into the first channel 213. After the acceleration of the air flow through the first channel 213, the air flow enters the second channel 215, at this time, the speed of the air flow is greatly increased and the turbulence is greatly reduced. The airflow, after passing through the vortex street generator 25, generates double-line vortices acting on two opposite sides of the scattering element 23 respectively, so that the scattering element 23 vibrates and generates displacement, and an included angle alpha between an optical path of laser and a normal direction D of the scattering element 23 is larger than 0 DEG and smaller than 90 DEG, so that vibration of the scattering element 23 in the normal direction D of the scattering element 23 can be decomposed into vibration perpendicular to the incident laser direction, the vibration is effective, and coherence of the laser can be reduced to a certain extent, thereby reducing speckle contrast.

In summary, in the laser projection display system 1 provided by the present invention, the scattering element 23 is driven to vibrate by the driving force generated by the fluid, the direct acting object of the vibration driver 25 is the fluid, rather than the projection component, and the flow characteristic of the fluid itself is that only the fluid needs to be slightly guided to generate the driving force for driving vibration, so that the structure of the vibration driver 25 is simpler, and no power component is needed. The method for driving the fluid to vibrate not only achieves the purpose of reducing speckle contrast, but also does not increase the complexity of a projection display system, and has strong practicability.

The foregoing examples illustrate only a few embodiments of the invention and are described in detail herein without thereby limiting the scope of the invention. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention.

Claims

1. A laser projection display system, comprising:

a laser generator for emitting laser light;

the scattering sheet vibration device comprises a fluid channel, a scattering element and a vibration driver, wherein the scattering element is arranged in the fluid channel in a vibrating way and is positioned in the optical path of laser, the vibration driver is a vortex street generator, the vortex street generator is arranged in the fluid channel and is used for enabling fluid in the fluid channel to generate driving force acting on the scattering element, the scattering element vibrates under the action of the driving force, and the scattering element vibrates at least along the vertical direction of the incident laser; and

2. The laser projection display system of claim 1, wherein the dual line vortex generated by the fluid passing through the vortex street generator is the driving force for the scattering element to vibrate.

3. The laser projection display system of claim 1, wherein an angle between a normal of the scattering element and the incident laser light is greater than 0 ° and less than 90 °.

4. A laser projection display system as claimed in claim 3, wherein the angle between the normal of the scattering element and the incident laser light is in the range 45 ° to 60 °.

5. The laser projection display system of claim 1, further comprising a heat sink channel in communication with the fluid channel, the fluid exiting the heat sink channel flowing into the fluid channel and acting on the vibration driver.

6. The laser projection display system of claim 1, wherein the fluid channel comprises a first channel and a second channel into which fluid flows in sequence, the first channel having a cross-sectional dimension that decreases progressively along the direction of flow of the fluid, the vibration driver and the scattering element being located in the second channel.

7. The laser projection display system of claim 6, wherein the vibration driver is a set distance from the fluid inlet of the second channel.

8. The laser projection display system of claim 2, wherein the axis of the vortex generator is perpendicular to the normal of the scattering element and perpendicular to the axis of the fluid channel, the vortex generator including an arcuate surface on a side of the vortex generator remote from the scattering element.

9. The laser projection display system of any of claims 1 to 7, wherein the diffusion sheet vibrating device further comprises an elastic member having one end connected to the diffusion element and the other end fixed to an inner wall of the fluid passage.

10. The laser projection display system of claim 9, wherein the scattering element is quadrilateral, the number of elastic members is four, each elastic member is connected to one corner of the scattering element, or