CN219016783U

CN219016783U - Laser projection display equipment

Info

Publication number: CN219016783U
Application number: CN202220736449.4U
Authority: CN
Inventors: 杨宁; 龚晨晟; 司继成
Original assignee: Suzhou Longmapu Chip Technology Co ltd
Current assignee: Suzhou Longmapu Chip Technology Co ltd
Priority date: 2022-03-30
Filing date: 2022-03-30
Publication date: 2023-05-12
Anticipated expiration: 2032-03-30

Abstract

The embodiment of the utility model discloses a laser projection display device, which comprises: a laser unit emitting a combined laser including at least two lasers of different colors; the micro-array retarder comprises a plurality of micro-retarders, the fast axis directions of the micro-retarders are randomly oriented, the combined laser is transmitted by the micro-array retarder, and the light rays passing through different micro-retarders form linearly polarized light with random polarization directions; a rotation unit driving the microarray retarder to rotate around a center point of the microarray retarder; and the first reflecting unit is used for projecting and imaging the combined laser transmitted through the microarray retarder by adjusting the posture of the reflecting surface. The embodiment of the utility model realizes the adjustment of laser beam combination to lose coherence, can effectively inhibit the speckle effect caused by coherent superposition, and solves the problem that the display quality can not meet the requirement due to the speckle effect in the existing projection display system.

Description

Laser projection display equipment

Technical Field

The embodiment of the utility model relates to the technical field of laser display, in particular to laser projection display equipment.

Background

Compared with the common light source, the laser has the advantages of high monochromaticity, coherence and directivity. However, due to the high coherence of the laser light, when the laser light is diffusely reflected at the surface of the diffuser or passes through a transparent diffuser (e.g., frosted glass), an irregularly distributed bright and dark spot is observed in the light field at or near the diffuser surface, which is known as laser speckle. Laser speckle is generated by the irradiation of coherent light by random scatterers and is therefore a random process.

The generation of speckle severely degrades the quality of a displayed image in terms of laser projection display and holographic display, and thus, suppression of speckle becomes a problem that must be solved by laser display.

Disclosure of Invention

The utility model provides laser projection display equipment, which is used for weakening the coherence of laser beams, inhibiting speckle effect caused by coherent superposition and ensuring the quality of display images.

An embodiment of the present utility model provides a laser projection display apparatus, including:

a laser unit emitting a combined laser including at least two lasers of different colors;

a microarray retarder comprising a plurality of micro retarders, wherein the fast axis directions of the micro retarders are randomly oriented, the combined laser is transmitted by the microarray retarder, and wherein light passing through different micro retarders forms linearly polarized light with random polarization directions;

a rotation unit driving the microarray retarder to rotate around a center point of the microarray retarder;

and the first reflecting unit is used for projecting and imaging the combined laser transmitted through the microarray retarder by adjusting the posture of the reflecting surface.

Optionally, the micro-retarder comprises a liquid crystal and a liquid crystal polymer, the liquid crystal polymer comprising a half-wave retardation material, the fast axes of the half-wave retardation materials in different ones of the micro-retarders being randomly oriented.

Optionally, the microarray retarder is in a ring shape, and a central axis of the microarray retarder is parallel to an optical axis of the combined laser.

Optionally, the device further comprises a beam expanding unit and a focusing unit, wherein the beam expanding unit is positioned on a light path between the laser unit and the microarray retarder, and the focusing unit is positioned on a light path between the microarray retarder and the first reflecting unit;

the beam expanding unit is used for expanding the beam of the beam-combining laser, and the focusing unit is used for focusing the beam-combining laser to the first reflecting unit.

Optionally, the beam expanding unit includes a concave lens and a first convex lens, and the focusing unit includes a second convex lens.

Optionally, the laser device further comprises a second reflection unit, wherein the second reflection unit is located on an optical path between the laser unit and the microarray retarder, and is used for changing the propagation direction of the combined laser through reflection and enabling the combined laser to be incident on the microarray retarder.

Optionally, the laser unit includes a red laser emitting unit, a green laser emitting unit, a blue laser emitting unit, and three dichroic mirrors respectively positioned on light emitting paths of the red laser emitting unit, the green laser emitting unit, and the blue laser emitting unit, and reflection light paths of the three dichroic mirrors overlap.

Optionally, the laser unit further includes three beam shaping lenses, and the three beam shaping lenses are respectively located on the light emitting paths of the red laser emitting unit, the green laser emitting unit and the blue laser emitting unit and correspondingly located between the red laser emitting unit, the green laser emitting unit and the blue laser emitting unit and the dichroic mirror.

Optionally, the rotating unit includes a rotating motor, and the first reflecting unit includes a MEMS galvanometer.

Optionally, the display device further includes a projection screen, and the first reflection unit projects the combined laser light transmitted by the microarray retarder onto the projection screen.

According to the technical scheme, a laser unit, a micro-array retarder, a rotating unit and a first reflecting unit are arranged in a laser projection display device, wherein the laser unit emits combined laser comprising at least two lasers with different colors, the micro-array retarder comprises a plurality of micro-retarders, the fast axis directions of the micro-retarders are randomly oriented, the combined laser is transmitted by the micro-array retarder, and light rays passing through different micro-retarders form linearly polarized light with random polarization directions; a rotation unit drives the microarray retarder to rotate around a center point of the microarray retarder; the first reflecting unit forms an image on the laser beam combining projection transmitted through the microarray retarder by adjusting the posture of the reflecting surface, so that the laser beam combining polarization state is adjusted, the coherence is lost, and the speckle effect caused by coherent superposition can be effectively restrained when diffuse reflection free superposition is carried out on the rough surface. The embodiment of the utility model solves the problem that the display quality cannot meet the requirement due to the speckle effect of the traditional projection display system, has simple and effective structure, has lower requirement on a screen, and has the advantages of low process requirement and low cost.

Drawings

Fig. 1 is a schematic structural diagram of a laser projection display device according to an embodiment of the present utility model.

Detailed Description

The utility model is described in further detail below with reference to the drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the utility model and are not limiting thereof. It should be further noted that, for convenience of description, only some, but not all of the structures related to the present utility model are shown in the drawings.

The terminology used in the embodiments of the utility model is for the purpose of describing particular embodiments only and is not intended to be limiting of the utility model. It should be noted that, the terms "upper", "lower", "left", "right", and the like in the embodiments of the present utility model are described in terms of the angles shown in the drawings, and should not be construed as limiting the embodiments of the present utility model. In addition, in the context, it will also be understood that when an element is referred to as being formed "on" or "under" another element, it can be directly formed "on" or "under" the other element or be indirectly formed "on" or "under" the other element through intervening elements. The terms "first," "second," and the like, are used for descriptive purposes only and not for any order, quantity, or importance, but rather are used to distinguish between different components. The specific meaning of the above terms in the present utility model will be understood in specific cases by those of ordinary skill in the art.

As described in the background art, when laser light is used as a light source with extremely high coherence, when the laser light irradiates on the surface of an optically rough object such as a screen, the laser light will be scattered randomly, so that the position where the coherence phenomenon occurs is also random, and after being imaged by the optical system, the laser light appears as a graininess random distribution pattern, namely as speckle, and the appearance of the laser speckle can seriously affect the quality of a picture.

Speckle suppression is generally achieved in a dynamic manner at present, and the principle adopted by the speckle suppression method is that superposition of a plurality of independent speckles is achieved within the integration time of a detector. Independent speckle is created by projecting a varying diffuser onto the screen, taking advantage of the variation in random phase of each diffuser pixel. Speckle dynamic suppression is a time-averaged approach at its root and generally comprises the following two types: (1) Projecting an image through a diffuser carrying phase information onto a screen, such as a deformable mirror composed of a continuous mirror element microarray structure; (2) a screen that introduces motion.

For both embodiments of speckle reduction, the use of deformable mirrors from a continuous mirror element microarray structure is quite complex, process demanding, and costly. The introduction of a motion screen makes the application scenario very limited. Firstly, the larger the screen size, which means the increase of weight and the increase of air resistance, the larger the burden is brought to the vibration motor; secondly, the screen is difficult to fix, and all parts of the screen cannot synchronously move, so that the picture is distorted and distorted; furthermore, the service life and the manufacturing cost of the screen are all gaps which are difficult to surmount.

Based on the technical problems, the embodiment of the utility model provides laser projection display equipment. Fig. 1 is a schematic structural diagram of a laser projection display device according to an embodiment of the present utility model, and referring to fig. 1, the laser projection display device includes: a laser unit 10 that emits a combined laser light 101 including at least two kinds of laser light of different colors; a micro-array retarder 20 including a plurality of micro-retarders whose fast axis directions are randomly oriented, and a combined laser light 101 transmitted by the micro-array retarder 20, and wherein light passing through different micro-retarders forms linearly polarized light having a random polarization direction; a rotation unit 30 driving the microarray retarder 20 to rotate around a center point of the microarray retarder 20; the first reflection unit 40 images the combined laser beam 101 transmitted through the microarray retarder 20 by adjusting the posture of the reflection surface.

The laser unit 10 is a light source of the entire projection display device, and provides a light beam related to picture information, and the first reflection unit 40 is a projection structure, and forms the light beam provided by the light source on a projection plane. It should be noted that, in this embodiment, the beam emitted by the laser unit 10 is used to form a single pixel point of the whole projection screen, the posture of the reflecting surface is adjusted by the first reflecting unit 40, so as to realize scanning of the laser beam on the projection plane, and the laser beam is configured as a light source according to the current pixel point of the projection screen while scanning, that is, the laser beam provided by the laser unit 10 is a dynamically adjusted laser beam, and is matched with the dynamic scanning of the second reflecting unit 40, and according to the vision residual principle of human eyes, a continuous projection screen can be formed on the projection plane to realize the display function. It can be understood that the process of dynamically adjusting the laser unit 10 can be understood as a process of realizing the required color of each pixel point of the projection picture by matching the laser beams with different colors according to different proportions, so that at least two laser sources with different colors need to be arranged in the laser unit 10 for beam combination.

Based on the above projection display principle, the present embodiment is further provided with a microarray retarder 20 and a rotation unit 30 for suppressing the laser speckle phenomenon formed by the combined laser light 101 emitted from the laser unit 10. Specifically, the rotation unit 30 drives the microarray retarder 20 to rotate, so that the combined laser light 101 emitted from the laser unit 10 is incident on different regions of the microarray retarder 20. Specifically, since the micro-array retarder 20 is provided with a plurality of micro-retarders, the combined laser 101 will be incident on different micro-retarders during rotation, and since the fast axis directions of the different micro-retarders are randomly oriented, the light beams in the combined laser 101 passing through the different micro-retarders will have different degrees of phase retardation, and it should be noted that the laser beams generated during practical application of the laser unit 10 are linear polarized light, and after the different degrees of phase retardation by the different micro-retarders, different polarization directions will be formed. In other words, from the cross-section, the light rays at different positions on the combined laser 101 will generate different linearly polarized light after passing through different micro retarders; since the micro-array retarder 20 is in a high-speed rotation state, the micro-retarders transmitted at different times are different for the light at the same position on the combined laser beam 101, that is, the light at the same position on the cross section in the combined laser beam 101 will also generate different linearly polarized light at different times. Therefore, for continuous projection images, the same pixel point in each picture can be formed by linearly polarized light projection in different polarization directions, so that laser beams forming the same pixel point in each picture are weak coherent beams, and the laser speckle effect can be greatly inhibited when the laser spots are overlapped, thereby avoiding the speckle effect from affecting the quality of the picture.

According to the technical scheme, a laser unit, a micro-array retarder, a rotating unit and a first reflecting unit are arranged in a laser projection display device, wherein the laser unit emits combined laser comprising at least two lasers with different colors, the micro-array retarder comprises a plurality of micro-retarders, the fast axis directions of the micro-retarders are randomly oriented, the combined laser is transmitted by the micro-array retarder, and light rays passing through the different micro-retarders form linearly polarized light with random polarization directions; the rotating unit drives the microarray retarder to rotate around the center point of the microarray retarder; the first reflecting unit is used for projecting and imaging the combined laser transmitted through the microarray retarder by adjusting the posture of the reflecting surface, so that the adjustment of the polarization state of the combined laser is realized, the laser loses coherence, and the speckle effect caused by coherent superposition can be effectively restrained when diffuse reflection free superposition is carried out on a rough surface. The embodiment of the utility model solves the problem that the display quality cannot meet the requirement due to the speckle effect of the traditional projection display system, has simple and effective structure, has lower requirement on a screen, and has the advantages of low process requirement and low cost.

As described in the above embodiments, the micro-retarder according to the present utility model may include a liquid crystal and a liquid crystal polymer, wherein the liquid crystal polymer includes a half-wave retardation material, and the fast axes of the half-wave retardation materials in different micro-retarders are randomly oriented. Therefore, the phase of the transmitted light beam can be delayed by utilizing half-wave delay materials in the liquid crystal and the liquid crystal polymer, so that the adjustment of the polarization state is realized, the random orientation of the fast axis directions of different micro retarders is realized, and the requirement of inhibiting the laser speckle effect is met.

Referring to fig. 1, the microarray retarder 20 may be provided in a ring shape, and a central axis of the microarray retarder 20 is parallel to an optical axis of the combined laser light 101. At this time, the combined laser 101 perpendicularly enters the micro-array retarder 20, and the polarization states of the light rays at different positions on the cross section of the combined laser 101 can be adjusted by different micro-retarders, so that the polarization states of the light rays are randomly arranged.

Further, in order to make more micro-retarders participate in the operation of the micro-array retarders, to increase the operation efficiency of the micro-array retarders, it is considered to expand the beam of the combined laser light, that is, to increase the cross-sectional area thereof. Specifically, a beam expanding unit 50 and a focusing unit 60 may be provided, the beam expanding unit 50 being located on an optical path between the laser unit 10 and the microarray retarder 20, the focusing unit 60 being located on an optical path between the microarray retarder 20 and the first reflecting unit 40; the beam expanding unit 50 is used for expanding the beam of the beam-combining laser light 101, and the focusing unit 60 is used for focusing the beam-expanding beam-combining laser light 101 onto the first reflecting unit 40. As shown in fig. 1, in an example embodiment, the beam expanding unit 50 may be provided to include a concave lens 51 and a first convex lens 52, and the focusing unit 60 may employ a second convex lens 61. In addition, for the front-rear positions of the concave lens 51 and the first convex lens 52 shown in the drawing, a person skilled in the art can selectively adjust, for example, the concave lens 51 can be disposed behind the first convex lens 52, and the beam expanding function can be realized by properly setting the pitch thereof. Similarly, the distance between the second convex lens 61 and the first reflecting unit 40 needs to be set reasonably, so that the combined laser beam 101 is focused on the reflecting surface of the first reflecting unit 40.

In addition, in order to save space of the entire apparatus, a display device may be provided including a second reflection unit 70, the second reflection unit 70 being located on an optical path between the laser unit 10 and the microarray retarder 20, the second reflection unit 70 being for changing a propagation direction of the combined laser light 101 by reflection and making the combined laser light 101 incident on the microarray retarder 20. The second reflecting unit 70 here may be a planar mirror in particular.

With continued reference to fig. 1, in a specific embodiment, the optional laser unit 10 includes a red laser light emitting unit 111, a green laser light emitting unit 112, a blue laser light emitting unit 113, and three dichroic mirrors 120 located on the light emitting paths of the red laser light emitting unit 111, the green laser light emitting unit 112, and the blue laser light emitting unit 113, respectively, with the reflection light paths of the three dichroic mirrors 120 overlapping.

The dichroic mirror 120 is a mirror having different reflectivity and transmittance properties for light of different wavelengths, and is commonly used in a beam combining and splitting structure of a laser beam. In this embodiment, a dichroic mirror 120 is disposed on each of the three laser beam paths, respectively, for controlling the energy ratio of the laser beams of the corresponding colors reflected by each mirror, and for adjusting the ratio of the laser beams of the colors in the combined beam. It will be appreciated that in the embodiment shown in fig. 1, the three laser emitting units with three colors are arranged with the exit paths parallel, and the three dichroic mirrors 120 are parallel, which is only one embodiment of the present utility model, and the positions of the laser reflecting units with each color may also be changed on the basis of meeting the overlapping of the reflection paths of the three dichroic mirrors 120 in consideration of different spatial arrangements, and accordingly, the inclination angles of the corresponding dichroic mirrors 120 need to be adjusted, and the structural layout design or the change in the laser units falls within the protection scope of the present utility model based on this.

Further alternatively, the laser unit 10 further includes three beam shaping lenses 130, and the three beam shaping lenses 130 are respectively located on the light emitting paths of the red laser emitting unit 111, the green laser emitting unit 112, and the blue laser emitting unit 113 and between the red laser emitting unit 111, the green laser emitting unit 112, and the blue laser emitting unit 113 and the dichroic mirror 120.

The beam shaping lens 130 is mainly used for shaping the laser beams emitted from the laser light emitting units of each color, and may include collimation, focusing, etc., so that the laser beams are incident on the dichroic mirror 120 for beam combination, which is not limited herein.

In a specific embodiment, the rotatable unit 30 may be provided to include a rotary motor 31. The rotating motor 31 may be disposed at the back of the microarray retarder 20, and drives the microarray retarder 20 to rotate through the rotating shaft. Of course, those skilled in the art may also design the specific structure of the rotary unit 30 according to actual needs, for example, other motors may be used to replace the rotary motor 31, or other transmission components may be added, which are not limited herein.

In a specific embodiment, the first reflecting unit 40 may also be provided to include a MEMS galvanometer 41. The first reflection unit 40 adopts the MEMS galvanometer 41, and can realize rapid scanning imaging by utilizing the high-speed posture conversion characteristic of the galvanometer. Of course, those skilled in the art may alternatively use other types of mirrors according to actual needs, and the utility model is not limited herein.

In a specific embodiment, the configurable display device further comprises a projection screen 80, and the first reflection unit 40 projects the combined laser light 101 transmitted by the microarray retarder 20 onto the projection screen 80.

Note that the above is only a preferred embodiment of the present utility model and the technical principle applied. It will be understood by those skilled in the art that the present utility model is not limited to the particular embodiments described herein, and that various obvious changes, rearrangements, combinations, and substitutions can be made by those skilled in the art without departing from the scope of the utility model. Therefore, while the utility model has been described in connection with the above embodiments, the utility model is not limited to the embodiments, but may be embodied in many other equivalent forms without departing from the spirit or scope of the utility model, which is set forth in the following claims.

Claims

1. A laser projection display device, comprising:

2. The laser projection display device of claim 1, wherein the micro-retarder comprises a liquid crystal and a liquid crystal polymer, the liquid crystal polymer comprising a half-wave retardation material, the fast axes of the half-wave retardation material in the micro-retarder being randomly oriented.

3. The laser projection display device of claim 1, wherein the microarray retarder is in a circular ring shape, and a central axis of the microarray retarder is parallel to an optical axis of the combined laser light.

4. The laser projection display device of claim 1, further comprising a beam expanding unit located on an optical path between the laser unit and the microarray retarder and a focusing unit located on an optical path between the microarray retarder and the first reflecting unit;

5. The laser projection display device of claim 4, wherein the beam expanding unit includes a concave lens and a first convex lens, and the focusing unit includes a second convex lens.

6. The laser projection display device of claim 1, further comprising a second reflecting unit located on an optical path between the laser unit and the microarray retarder, the second reflecting unit being configured to change a propagation direction of the combined laser light by reflection and make the combined laser light incident on the microarray retarder.

7. The laser projection display device of claim 1, wherein the laser unit comprises a red laser emitting unit, a green laser emitting unit, a blue laser emitting unit, and three dichroic mirrors positioned on light emitting paths of the red laser emitting unit, the green laser emitting unit, and the blue laser emitting unit, respectively, and reflection light paths of the three dichroic mirrors overlap.

8. The laser projection display device of claim 7, wherein the laser unit further comprises three beam shaping lenses, the three beam shaping lenses being positioned on the light exit paths of the red, green and blue laser emitting units, respectively, and between the red, green and blue laser emitting units and the dichroic mirror, respectively.

9. The laser projection display device of claim 1, wherein the rotation unit comprises a rotating motor and the first reflection unit comprises a MEMS galvanometer.

10. The laser projection display device of claim 1, further comprising a projection screen, wherein the first reflection unit projects the combined laser light transmitted by the microarray retarder onto the projection screen.