CN112859497B - Laser projection display system - Google Patents

Abstract

The invention provides a laser projection display system, which includes a laser generator, a scattering sheet vibration device and a projection imaging device. Among them, the laser generator is used to emit laser light. The vibration device of the scattering sheet includes a fluid channel, a scattering element and a vibration driver, the scattering element can be vibrated in the fluid channel and is located in the optical path of the laser, and the vibration driver is used to make the fluid in the fluid channel generate a 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 light. The projection imaging device is located on the optical path of the laser light, and is used for modulating the laser light 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 the system is simple and practical.

Description

Laser projection display system

technical field

The present invention relates to the field of optical technology, in particular to a laser projection display system.

Background technique

Laser has the characteristics of high brightness, good monochromaticity, and strong directionality. When using laser as a projection light source, the picture obtained has a large color gamut and can display more realistic and rich colors. However, due to the strong coherence of laser light, speckles will be generated during imaging, which reduces the resolution of the picture and affects the imaging quality. In order to solve the speckle problem, many scientific researchers have invested in it and proposed a variety of methods to reduce the speckle contrast, such as using light sources of different wavelengths to reduce the coherence of light sources, and making display chips, projectors and projection screens vibrate, etc. methods to reduce speckle contrast, but these vibration methods have certain technical difficulties, and need to add a vibration drive device with a complex structure and power components (such as an engine), which increases the complexity of the system and limits its practicability , it is difficult to meet user needs.

Contents of the invention

The object of the present invention is to provide a laser projection display system to solve the above problems.

Embodiments of the present invention achieve the above object through the following technical solutions.

The present invention provides a laser projection display system, comprising:

a laser generator for emitting laser light;

The vibration device of the scattering sheet, the vibration device of the scattering sheet includes a fluid channel, a scattering element and a vibration driver, the scattering element can be vibrated in the fluid channel and is located in the optical path of the laser, and the vibration driver is used for causing the fluid in the fluid channel to generate a 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 light; and

The projection imaging device is located on the optical path of the laser light, and is used for modulating the laser light 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 generator, and the vortex generator is arranged in the fluid channel, and the double-row linear vortex generated by the fluid passing through the vortex generator is the scattering The driving force for a component to vibrate.

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

In one embodiment, the included angle between the normal direction of the scattering element and the incident laser light ranges from 45° to 60°.

In one embodiment, the laser projection display system further includes a heat dissipation channel, the heat dissipation channel communicates with the fluid channel, and the fluid flowing out of the heat dissipation channel flows into the fluid channel and acts on the vibration driver.

In one embodiment, the fluid channel includes a first channel and a second channel into which fluid flows in sequence, along the flow direction of the fluid, the cross-sectional size of the first channel gradually decreases, the vibration driver and the A scattering element is located in the second channel.

In one embodiment, there is a set distance between the vibration driver and the fluid inlet of the second channel.

In one embodiment, the axis of the vortex generator is perpendicular to the normal direction of the scattering element and perpendicular to the axis of the fluid channel, the vortex generator includes an arc, and the arc is located at the The side of the vortex generator away from the scattering element.

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

In one embodiment, the scattering element is quadrangular, the number of the elastic members is four, and each of the elastic members connects a corner of the scattering element, or

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

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

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

Compared with the prior art, the laser projection display system provided by the present invention drives the vibration of the scattering element through the driving force generated by the fluid. The direct action object of the vibration driver is the fluid, not the projection component. The flow characteristics of the fluid itself make it only necessary to With a little guidance, the driving force to drive the vibration can be generated, so the vibration driver has a simpler structure and does not need to have power components. The method for driving fluid vibration of the present invention not only achieves the purpose of reducing speckle contrast, but also does not increase the complexity of the projection display system, and has strong practicability.

These or other aspects of the present invention will be more clearly understood in the description of the following embodiments.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings that need to be used in the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application. For those skilled in the art, other drawings can also be obtained based on these drawings without any creative effort.

FIG. 1 is a schematic structural diagram of a laser projection display system provided by an embodiment of the present invention.

FIG. 2 is a schematic structural diagram of a heat dissipation channel and a vibration device for a scattering plate of a laser projection display system provided by an embodiment of the present invention.

Fig. 3 is a schematic perspective view of the second channel of the laser projection display system provided by the embodiment of the present invention, and the vibrating plate, the vortex generator and the elastic member arranged in the second channel.

FIG. 4 is an optical path diagram of a laser projection display system provided by an embodiment of the present invention.

FIG. 5 is a morphological diagram of a dicolumn vortex in a laser projection display system provided by an embodiment of the present invention.

Fig. 6 is a simulation diagram of the flow velocity of the fluid in the fluid channel of the laser projection display system provided by the embodiment of the present invention.

Fig. 7 is a simulation diagram of the degree of turbulence of the fluid in the fluid channel of the laser projection display system provided by the embodiment of the present invention.

Fig. 8 is a cross-sectional view of a vortex generator of a laser projection display system provided by an embodiment of the present invention.

Fig. 9 is a cross-sectional view of another vortex generator of the laser projection display system provided by the embodiment of the present invention

Detailed ways

In order to facilitate understanding of the embodiments of the present invention, the embodiments of the present invention will be more fully described below with reference to the relevant drawings. Preferred embodiments of the invention are shown in the accompanying drawings. However, the present invention can be embodied in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field of the invention. The terminology used herein in the embodiments of the present invention is only for the purpose of describing specific implementation manners, and is not intended to limit the present invention.

Referring to FIG. 1 and FIG. 2 , the laser projection display system 1 provided by the present invention includes a laser generator 10 , a scattering plate vibrating device 20 and a projection imaging device 30 . Wherein, the laser generator 10 is used to emit laser light. The scattering sheet vibrating device 20 includes a fluid channel 21, a scattering element 23 and a vibration driver 25. The scattering element 23 can be vibrated in the fluid channel 21 and is located in the optical path of the laser. The vibration driver 25 is used to make the fluid in the fluid channel 21 generate The driving force acts on the scattering element 23, the scattering element 23 vibrates under the action of the driving force, and the scattering element 23 vibrates at least along the vertical direction of the incident laser light. The projection imaging device 30 is located on the optical path of the laser light, and is used for modulating the laser light emitted from the scattering element 23 into image light, and projecting the image light to the projection screen 80 for imaging.

In a preferred embodiment, the vibration driver 25 is a vortex generator, and the vortex generator is arranged in the fluid channel 21, and the double row linear vortex (as shown in Figure 5 ) that the fluid passes through the vortex generator is a scattering element. 23 The driving force of the vibration occurs.

Specifically, in this embodiment, the laser generator 10 is used to emit laser light, the laser generator 10 includes a laser, and the laser generator 10 can be a red laser generator 10, a blue laser generator 10 and a green laser generator 10 any of the. Laser generator 10 may include one or two lasers. The laser generator 10 can also be a laser array, which includes multiple lasers, and the distance between each laser and its adjacent lasers can be very small, so that the light-emitting surface of each laser in the laser array together forms a surface light source. The specific number of lasers can be selected according to actual needs. The laser can be a laser diode (LD) or a light emitting diode (LED).

Please refer to Fig. 2 and Fig. 3, the scattering sheet vibration device 20 is used to vibrate the scattering element 23, and make the scattering element 23 have a certain displacement in the normal direction of the scattering element 23, reduce the laser speckle contrast, and improve the laser projection display system. 1 image quality.

In this embodiment, the fluid channel 21 is roughly in the shape of a hollow cylinder, and the fluid channel 21 includes a first channel 213 and a second channel 215 through which fluid flows sequentially. Wherein, the second channel 215 is a hollow cuboid, and the cross-sectional dimensions of the second channel 215 are constant values. In an optional embodiment, the first channel 213 is a hollow rectangular prism, and along the flow direction of the fluid, the cross-sectional size of the first channel 213 gradually decreases to accelerate the fluid passing through the first channel 213, as shown in the figure 6, along the flow direction of the fluid, the velocity of the fluid increases gradually. The first channel 213 can also reduce the turbulence of the fluid. As shown in FIG. 7 , along the flow direction of the fluid, the turbulence of the fluid gradually decreases.

In other optional embodiments, the cross-sectional dimensions of the first channel 213 and the second channel 215 can be fixed and the same; or the cross-sectional size of the first channel 213 is fixed and smaller than that of the second channel 215 . In one embodiment, the first channel 213 is hollow circular truncated, and the second channel 215 may be hollow cylindrical; the first channel 213 is hollow triangular prism, etc., and the second channel 215 may be hollow triangular prism. The shape and cross-sectional size of the fluid channel 21 can be designed according to the actual situation, which needs to meet the requirement of generating a Karman vortex street in the fluid channel 21 .

As shown in Figure 3, the second channel 215 includes a relative fluid inlet 2152 and a fluid outlet 2154, wherein the fluid inlet 2152 is directly connected with the first channel 213, and the fluid flows out from the first channel 213 and enters the second channel 215 through the fluid inlet 2152 And out through the fluid outlet 2154.

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

In other optional embodiments, the fluid channels 21 may all be light-transmitting structures, and the light transmittance of each part of the fluid channels 21 may be the same or different.

Referring to FIG. 2 and FIG. 4, the scattering element 23 can be a transmissive scattering element 23 or a reflective scattering element 23. The vibration of the scattering element 23 makes the phase difference of the transmitted (reflected) light different, thereby producing different speckles. These different speckle superpositions can reduce the speckle contrast during the integration time of the human eye.

The scattering element 23 is vibratingly arranged in the fluid channel 21 and located in the optical path of the laser light. The scattering element 23 vibrates under the action of the dicolumn vortex. The scattering element 23 vibrates at least along the vertical direction of the incident laser light. In order to enable 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. The vibration of the direction can be decomposed into the vibration perpendicular to the direction of the incident laser, which is an effective vibration, which can reduce the coherence of the laser to a certain extent, thereby reducing the speckle contrast. In this 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 direction D of the scattering element 23 and the optical path of the laser light may range from 45° to 60°. When the angle α between the normal direction D of the scattering element 23 and the optical path of the laser light is less than 45 degrees, the spot size on the scattering element 23 will gradually increase, which will affect 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 actual operation, in order to balance the imaging quality and the effect of reducing speckle, it is generally recommended that the angle α between the normal direction D of the scattering element 23 and the optical path of the laser light be in the range of 45°-60°. However, in other optional embodiments, the angle α between the normal direction D of the scattering element 23 and the optical path of the laser can also be set to other angle ranges according to actual needs, for example, the angle range is 15°-75°, etc. .

Please continue to refer to 2. In this embodiment, the scattering plate vibrating device 20 also includes an elastic member 40. On the one hand, the elastic member 40 can be used to fix the scattering element 23, and on the other hand, it can also convert the pressure of the fluid into the pressure of the scattering element 23. displacement. 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 channel 21 . The elastic member 40 may be a spring with a small elastic coefficient, so as to resonate, so that the vibration displacement of the scattering element 23 is greatly increased, and the speckle contrast is significantly reduced. The scattering element 23 is arranged in the second channel 215, specifically, the scattering element 23 is vibrately arranged in the fluid channel 21, the scattering element 23 is quadrilateral, and the number of the elastic members 40 is four, and each elastic member 40 is connected to the scattering element A corner of 23.

In other embodiments, the scattering element 23 may also be in the shape of a circle, a triangle, a hexagon, or the like. The quantity of the elastic member 40 can also be two, three or more, and the position of the elastic member 40 can also be distributed in other forms, such as the scattering element 23 is a quadrangle, the quantity of the elastic member 40 can be two, two elastic The member 40 connects two opposite sides of the scattering element 23 to arrange the scattering element 23 in the second channel 215 . For another example, the scattering element 23 is circular, and the number of elastic members 40 can be two, wherein one elastic member 40 can be connected to an inner wall of the scattering element 23 and the second channel 215, and the other elastic member 40 can be arranged at intervals and connected on the other inner wall of the scattering element 23 and the second channel 215 . For another example, the scattering element 23 is triangular in 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 can understand that the number of elastic members 40 , the shape of the scattering element 23 and the arrangement of the scattering element 23 in the second channel 215 can also be in various other forms.

In this embodiment, the vortex generator has a cylindrical shape, and the vortex generator is used to make the fluid in the fluid channel 21 generate a driving force acting on the scattering element 23, thereby reducing the speckle contrast. Specifically, a vortex street generator can be used to form a Karman vortex street. The principle of the Karman vortex street generated by the vortex street generator is: the vortex street generator acts as a disturbing body, and when the steady fluid bypasses its surface, the two sides of the vortex street generator periodically fall off double row lines with opposite rotation directions and regular arrangement. vortex, forming a Karman vortex street.

The vortex generator can include a curved surface, and the curved surface is located on the side of the vortex generator away from the scattering element 23, and the cross section of the vortex generator can be circular or annular (as shown in Figure 8). In this implementation In an example, the vortex generator can be a cylinder with a diameter of 2mm. It should be noted that the size of the vortex generator is specifically set based on the size of the fluid channel and the magnitude of the driving force to be generated.

Please refer to FIG. 9 , in other embodiments, the vortex generator may also include a plane connected to the arc surface, and the cross section of the vortex generator may be semicircular or semicircular. In other embodiments, the vortex street generator can also be in other shapes, such as elliptical cylinder, cube and other shapes.

Please continue to refer to FIG. 2 and FIG. 4, the vibration driver 25 is arranged in the fluid channel 21 and adjacent to the scattering element 23, specifically, the vibration driver 25 is located in the second channel 215, and the vibration driver 25 is close to the second channel 215 relative to the scattering element 23. One channel 213. The vibration driver 25 is located between the fluid inlet 2152 and the fluid outlet 2154, that is, there is a set distance between the vibration driver 25 and the fluid inlet 2152 of the second channel 215, which can reduce the inlet effect of the fluid and further reduce the degree of turbulence, satisfying the constant fluid condition.

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

Please continue to refer to FIG. 1 and FIG. 2 , the projection imaging device 30 is located on the optical path of the laser light, and is used 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. The projection imaging device 30 may include optical devices such as a color wheel, a spatial light modulator, and a lens.

The laser projection display system 1 also includes a heat dissipation channel 50 , which can be used to reduce the temperature of each component in the laser projection display system 1 . Specifically, the working temperature of components such as the laser generator 10 is relatively high, and the heat emitted by heating components such as the laser generator 10 can be dissipated to the external environment through the heat dissipation channel 50 . Generally speaking, the heat dissipation channel 50 utilizes air flow, ie, wind, to dissipate heat from heating elements such as the laser generator 10 . Air is also a fluid and can also be used to create Karman vortex streets. Therefore, in one embodiment, the heat dissipation channel 50 communicates with the fluid channel 21 , specifically, the heat dissipation channel 50 communicates with the first channel 213 , and the fluid flowing out of 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 causing the scattering element 23 to vibrate.

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

The laser projection display system 1 further includes a collimating lens 70 and a projection screen 80 , and the collimating lens 70 is located between the scattering sheet vibrating device 20 and the projection imaging device 30 . The collimating lens 70 is used to collimate the laser light. The projection imaging device 30 is located between the collimator lens 70 and the projection screen 80, and the projection screen 80 may be an LED display screen or the like.

The following is the working principle of the laser projection display system 1 provided by the present invention to reduce the speckle contrast:

The heat dissipated by the laser generator 10 and other components with high heat generation passes through the cooling channel 50 to form an airflow and flows into the first channel 213 . The airflow enters the second passageway 215 after being accelerated by the first passageway 213 , at this moment, the speed of the airflow is greatly increased and the degree of turbulence is greatly reduced. After the air flow passes through the vortex street generator 25, dicolumn vortices are generated that respectively act on the opposite sides of the scattering element 23, causing the scattering element 23 to vibrate and generate displacement, and the included angle α between the optical path of the laser and the normal direction D of the scattering element 23 is Greater than 0° and less than 90°, so that 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 and can reduce the coherence of the laser light to a certain extent , so that the speckle contrast can be reduced.

To sum up, the laser projection display system 1 provided by the present invention drives the scattering element 23 to vibrate through the driving force generated by the fluid. The direct action object of the vibration driver 25 is the fluid, not the projection component. With guidance, the driving force for driving vibration can be generated. Therefore, the structure of the vibration driver 25 is simpler, and no power components are required. The method for driving fluid vibration of the present invention not only achieves the purpose of reducing speckle contrast, but also does not increase the complexity of the projection display system, and has strong practicability.

The above-mentioned embodiments only express several implementation modes of the present invention, and the description thereof is relatively specific and detailed, but should not be construed as limiting the patent scope of the present invention. It should be noted that, for those skilled in the art, several modifications and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention.

Claims (10)

1. A laser projection display system, characterized in that, comprising: a laser generator for emitting laser light; The vibration device of the scattering sheet, the vibration device of the scattering sheet includes a fluid channel, a scattering element and a vibration driver, the scattering element can be vibrated in the fluid channel and is located in the optical path of the laser, and the vibration driver is a vortex A street generator, the vortex generator is arranged in the fluid channel, and the vortex generator is used to make the fluid in the fluid channel generate a driving force acting on the scattering element, and the scattering element is in the Vibrating under the action of the driving force, the scattering element vibrates at least along the vertical direction of the incident laser light; and The projection imaging device is located on the optical path of the laser light, and is used for modulating the laser light emitted from the scattering element into image light, and projecting the image light to a projection screen for imaging. 2 . The laser projection display system according to claim 1 , wherein the dicolumn vortex generated by the fluid passing through the vortex street generator is the driving force for the vibration of the scattering element. 3 . 3 . The laser projection display system according to claim 1 , wherein the included angle between the normal direction of the scattering element and the incident laser light is greater than 0° and less than 90°. 4 . The laser projection display system according to claim 3 , wherein the included angle between the normal direction of the scattering element and the incident laser light is in the range of 45° to 60°. 5. The laser projection display system according to claim 1, characterized in that, the laser projection display system further comprises a heat dissipation channel, the heat dissipation channel communicates with the fluid channel, and the fluid flowing out of the heat dissipation channel flows into the Fluid passages and acts on the vibration driver. 6. The laser projection display system according to claim 1, wherein the fluid channel comprises a first channel and a second channel into which fluid flows sequentially, and along the flow direction of the fluid, the cross-section of the first channel Decreasing in size, the vibration driver and the scattering element are located in the second channel. 7. The laser projection display system according to claim 6, wherein there is a set distance between the vibration driver and the fluid inlet of the second channel. 8. The laser projection display system according to claim 2, wherein the axis of the vortex generator is perpendicular to the normal direction of the scattering element and perpendicular to the axis of the fluid channel, the vortex The generator includes an arc surface, and the arc surface is located on a side of the vortex street generator away from the scattering element. 9. The laser projection display system according to any one of claims 1-7, wherein the vibration device for the scattering sheet further comprises an elastic member, one end of the elastic member is connected to the scattering element, and the other end is fixed on the inner wall of the fluid channel. 10. The laser projection display system according to claim 9, wherein the scattering element is quadrilateral, the number of the elastic members is four, and each elastic member connects a corner of the scattering element ,or The scattering element is circular and the number of the elastic members is an even number, or The scattering element is triangular, and the number of the elastic members is three, or The scattering element is hexagonal, and the number of the elastic members is three or six.

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