CN111596518B - Speckle-free laser projection equipment - Google Patents
Speckle-free laser projection equipment Download PDFInfo
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- CN111596518B CN111596518B CN202010499500.XA CN202010499500A CN111596518B CN 111596518 B CN111596518 B CN 111596518B CN 202010499500 A CN202010499500 A CN 202010499500A CN 111596518 B CN111596518 B CN 111596518B
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
- G03B21/00—Projectors or projection-type viewers; Accessories therefor
- G03B21/14—Details
- G03B21/20—Lamp housings
- G03B21/2073—Polarisers in the lamp house
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/48—Laser speckle optics
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- G—PHYSICS
- G02—OPTICS
- G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
- G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour
- G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells
- G02F1/1313—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour based on liquid crystals, e.g. single liquid crystal display cells specially adapted for a particular application
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
- G03B21/00—Projectors or projection-type viewers; Accessories therefor
- G03B21/005—Projectors using an electronic spatial light modulator but not peculiar thereto
- G03B21/006—Projectors using an electronic spatial light modulator but not peculiar thereto using LCD's
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
- G03B21/00—Projectors or projection-type viewers; Accessories therefor
- G03B21/14—Details
- G03B21/20—Lamp housings
- G03B21/2006—Lamp housings characterised by the light source
- G03B21/2033—LED or laser light sources
Abstract
The application discloses no speckle laser projection equipment includes: the device comprises a laser projector (1), a first liquid crystal phase adjusting unit (2), a first optical path compensating unit (3), a liquid crystal light valve (4), a control unit (5) and a first linear polarizer (7); the laser projector (1) is used for emitting projection beams, the projection beams comprise a first projection beam (S1) and a second projection beam (S2), and the first projection beam (S1) and the second projection beam (S2) have different heights in a plane of a paper surface. Adopt the speckle-free laser projection equipment that this application is disclosed, need not to vibrate the screen, can not lead to the screen to relax and the screen inhales the ash, do not have vibration system's reliability problem.
Description
Technical Field
The application belongs to the technical field of projection, and particularly relates to a speckle-free laser projection device.
Background
With the rapid development of laser semiconductor device technology in the last decade, the transition of projection display from bulb light source to laser light source has become a trend. However, due to the coherence of laser, the projected image will form laser speckle with irregular brightness, which affects the viewing effect of the audience. The prior art often adopts a method of vibrating a screen to eliminate speckles.
In the process of implementing the present application, the inventors found that at least the following problems exist in the prior art: although the vibrating screen has good effect of eliminating speckles, the reliability of the vibrating assembly is low, and the vibration easily causes the screen to be loose and the light effect to be seriously influenced by dust absorption of the screen.
Disclosure of Invention
The embodiment of the application aims to provide a speckle-free laser projection device, which can solve the speckle problem of laser projection and solve the problems of screen looseness, dust absorption and low system reliability caused by a vibrating screen speckle elimination scheme.
The application is realized as follows:
the embodiment of the application provides a no speckle laser projection equipment, includes: the device comprises a laser projector (1), a first liquid crystal phase adjusting unit (2), a first optical path compensating unit (3), a liquid crystal light valve (4), a control unit (5) and a first linear polarizer (7);
the laser projector (1) is used for emitting projection beams, the projection beams comprise a first projection beam (S1) and a second projection beam (S2), and the first projection beam (S1) and the second projection beam (S2) have different heights in a paper plane;
after a projection light beam emitted by the laser projector (1) passes through the first linear polarizer (7), the projection light beam is changed into linearly polarized light incident according to a first direction and is incident to the first liquid crystal phase adjusting unit (2), and the optical axis of the first liquid crystal phase adjusting unit (2) is parallel to or perpendicular to the light transmission axis of the first linear polarizer (7);
the first liquid crystal phase adjusting unit (2) and the first optical path compensating unit (3) are sequentially arranged on a propagation path of the projection light beam;
the first liquid crystal phase adjusting unit (2) has different thicknesses in a first direction of propagation of the projection light beam, the first liquid crystal phase adjusting unit (2) is electrically connected with the control unit (5), the first liquid crystal phase adjusting unit (2) receives a first voltage with a voltage value randomly changing along with time, after the projection light beam passes through the first liquid crystal phase adjusting unit (2), the propagation direction of the projection light beam is adjusted from the first direction to a second direction, the phase of the first projection light beam (S1) is adjusted from a first phase to a second phase, and the phase of the second projection light beam (S2) is adjusted from the first phase to a third phase; the variation period of the first voltage is less than the human eye integration time;
the first optical path compensation unit (3) is arranged on a propagation path of the projection light beam propagating along the second direction, and after the projection light beam passes through the first optical path compensation unit (3), the propagation direction of the projection light beam is changed from the second direction to the first direction;
the liquid crystal light valve (4) is electrically connected with the control unit (5), the liquid crystal light valve (4) is located on a propagation path of the projection light beams along the first direction, and the control unit (5) adjusts the liquid crystal light valve (4) to enable the first projection light beams (S1) and the second projection light beams (S2) with different phases to be changed into right-handed circularly polarized light or left-handed circularly polarized light according to the frame sequence.
Preferably, the light output of the laser projector (1) is partially polarized light with high degree of polarization, the laser projector (1) further comprises a first phase retarder (6), and the polarization direction of the polarized light after passing through the first phase retarder (6) of the laser projector (1) is the same as the direction of the light transmission axis of the first linear polarizer (7).
Preferably, the polarization degree of the laser projector is greater than 80%, and the transmittance of the emergent light of the laser projector after passing through the first phase retarder (6) and the first linear polarizer (7) is greater than 81%.
Preferably, the first liquid crystal phase adjusting unit (2) and the first optical path compensation unit (3) are both in a shuttle shape, and the vertical cross sections of the first liquid crystal phase adjusting unit (2) and the first optical path compensation unit (3) are both right trapezoid.
Preferably, the first liquid crystal phase adjusting unit (2) includes: the liquid crystal display device comprises a glass substrate (21) and liquid crystal (22) filled in the glass substrate, wherein the first optical path compensation unit (3) is flat glass.
Preferably, the speckle-free laser projection device further comprises at least one phase adjusting unit group consisting of a liquid crystal phase adjusting unit and an optical path compensating unit, wherein a liquid crystal optical axis in the phase adjusting unit group is perpendicular to or parallel to the first linear polarizer (7), and the phase adjusting unit group is arranged on an optical path between the first linear polarizer (7) and the liquid crystal light valve (4).
Preferably, the liquid crystal light valve (4) comprises a first sub-light valve (41) and a second sub-light valve (42) with mutually perpendicular optical axes, and the optical axis of the first linear polarizer (7) is at 45 degrees or minus 45 degrees with respect to the optical axis of the first sub-light valve (41).
Preferably, the laser projector (1), the first liquid crystal phase adjusting unit (2), the first optical path compensating unit (4), the liquid crystal light valve (4), the control unit (5) and the first linear polarizer (7) are fixedly connected; during both 2D and 3D projection, the liquid crystal light valve (4) is in a first state, on the propagation path of the projection beam.
Preferably, the laser projector (1), the first linear polarizer (7), the first liquid crystal phase adjusting unit (2), the first optical path compensating unit (4) and the liquid crystal light valve (4) may be sequentially bonded into a whole according to an optical path.
Preferably, the control unit (5) may be external to the whole, or internal to the laser projector (1).
Preferably, the speckle-free laser projection apparatus further includes a second linear polarizer (10), the second linear polarizer (10) is disposed in front of the liquid crystal light valve (4) and is close to the liquid crystal light valve (4), the laser projector (1), the first linear polarizer (7), the first liquid crystal phase adjusting unit (2) and the first optical path compensating unit (3) are fixedly connected, and the second linear polarizer (10) and the liquid crystal light valve (4) are fixedly connected to form an optical valve assembly.
Preferably, the light valve assembly is always located on the propagation path of the projection light beam when in the first state; when the light valve component is in the second state, the light valve component avoids the propagation path of the projection light beam.
Preferably, when the projection device performs 3D projection, the light valve assembly is in the first state, and the liquid crystal light valve (4) receives the second voltage output by the control unit (5); when the projection device performs 2D projection, the light valve assembly is in the second state.
In the embodiment of the application, by arranging a first liquid crystal phase adjusting unit in the propagation path of the projection light beam, the first liquid crystal phase adjusting unit has different thicknesses in the first direction of the propagation of the projection light beam, and the first liquid crystal phase adjusting unit receives a first voltage with the voltage value output by the control unit randomly changing along with time, so that the phase of coherent light on a wave front perpendicular to the propagation direction is randomized when the projection light beam passes through the first liquid crystal phase adjusting unit, thereby weakening the spatial coherence and eliminating the speckle. By adopting the speckle-free laser projection equipment disclosed by the invention, the screen does not need to be vibrated, the screen cannot be loosened, the screen cannot absorb dust, and the reliability problem of a vibration system is solved.
Drawings
FIG. 1 is a schematic structural diagram of a speckle-free laser projection apparatus according to an embodiment of the present invention;
FIG. 2 is a schematic structural diagram of a first liquid crystal phase adjusting unit according to an embodiment of the present invention;
FIG. 3 is a schematic structural diagram of another speckle-free laser projection apparatus provided by an embodiment of the invention;
fig. 4 is a schematic diagram illustrating relative angles of optical axes of a first liquid crystal phase adjusting unit, a first sub-light valve, and a second sub-light valve according to an embodiment of the present invention;
fig. 5 is a schematic diagram illustrating relative angles of optical axes of the first liquid crystal phase adjusting unit, the first sub-light valve, and the second sub-light valve according to another embodiment of the invention;
fig. 6 is a schematic structural diagram of another speckle-free laser projection apparatus according to an embodiment of the present invention.
Description of reference numerals:
the device comprises a laser projector 1, a first liquid crystal phase adjusting unit 2, a glass substrate 21, a liquid crystal 22, a first optical path compensating unit 3, a liquid crystal 4, a first sub-light valve 41, a second sub-light valve 42, a control unit 5, a first phase retarder 6, a first linear polarizer 7, a second liquid crystal phase adjusting unit 8, a second optical path compensating unit 9, a second linear polarizer 10, a first projection beam S1 and a second projection beam S2.
The implementation, functional features and advantages of the objects of the present invention will be further explained with reference to the accompanying drawings in combination with embodiments.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
The terms first, second and the like in the description and in the claims of the present application are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It will be appreciated that the data so used may be interchanged under appropriate circumstances such that embodiments of the application may be practiced in sequences other than those illustrated or described herein, and that the terms "first," "second," and the like are generally used herein in a generic sense and do not limit the number of terms, e.g., the first term can be one or more than one.
The following describes the photographing apparatus provided in the embodiments of the present application in detail through specific embodiments and application scenarios thereof with reference to the accompanying drawings.
Referring to fig. 1, a schematic structural diagram of a speckle-free laser projection apparatus provided in this embodiment is shown. The projection device specifically includes: the device comprises a laser projector 1, a first phase retarder 6, a first linear polarizer 7, a first liquid crystal phase adjusting unit 2, a first optical path compensating unit 3, a liquid crystal light valve 4 and a control unit 5.
The laser projector 1 is used for emitting a projection beam, which includes a first projection beam S1 and a second projection beam S2, where the first projection beam S1 and the second projection beam S2 have different heights in the plane of the paper, and both may be horizontal light or angled light.
The laser projector 1 may alternately play the left-eye image and the right-eye image, for example, play the images in frames, where the first frame plays the left-eye image, the second frame plays the right-eye image, the third frame plays the left-eye image, the fourth frame plays the right-eye image, \8230 \ 8230 \, and so on.
After the projection beam emitted from the laser projector 1 passes through the first phase retarder 6 and the first linear polarizer 7, the direction of the projection beam is adjusted to a first direction and enters the first liquid crystal phase adjusting unit 2. The first phase retarder 6 may convert polarized light in the projection beam into linearly polarized light parallel to the transmission axis direction of the first linear polarizer 7, and the first linear polarizer 7 may further filter the transmitted light into the projection beam with a specific polarization direction. The transmission axis of the first linear polarizer 7 is parallel or perpendicular to the optical axis of the first liquid crystal phase adjusting unit 2.
The first liquid crystal phase adjusting unit 2 and the first optical path compensating unit 3 are sequentially arranged on a propagation path of the projection light beam, and the first projection light beam S1 and the second projection light beam S2 sequentially pass through the first liquid crystal phase adjusting unit 2 and the first optical path compensating unit 3 in a propagation process.
The first liquid crystal phase adjusting unit 2 has different thicknesses in a first direction of the projection light beam propagation, the first liquid crystal phase adjusting unit 2 is electrically connected with the control unit 5, the first liquid crystal phase adjusting unit 2 receives a first voltage with a voltage value randomly changing along with time, the first liquid crystal phase adjusting unit 2 adjusts the propagation direction of the projection light beam from the first direction to a second direction after the projection light beam passes through the first liquid crystal phase adjusting unit 2, the phase of the first projection light beam S1 is adjusted from the first phase to a second phase, and the phase of the second projection light beam S2 is adjusted from the first phase to a third phase. A voltage whose voltage value varies randomly with time is applied to the first liquid crystal phase adjusting unit 2 to achieve randomization of the coherent light phase. Wherein, the variation period of the first voltage is far less than the human eye integration time.
The first optical path compensation unit 3 is disposed on a propagation path of the projection light beam propagating along the second direction, after the projection light beam passes through the first optical path compensation unit 3, the propagation direction of the projection light beam is changed from the second direction to the first direction, and the first optical path compensation unit 3 is configured to readjust the propagation direction of the projection light beam to the first direction.
Optionally, the first liquid crystal phase adjusting unit 2 and the first optical path compensating unit 3 are both in a shuttle shape, and the vertical cross sections of the first liquid crystal phase adjusting unit 2 and the first optical path compensating unit 3 are both right trapezoid. The first liquid crystal phase adjusting unit 2 adopting the wedge-shaped design can form different liquid crystal thicknesses at different emergent positions, so that projection light beams at different emergent positions have different phase offsets under control voltage.
Further, the first liquid crystal phase adjusting unit 2 and the first optical path compensating unit 3 may be a shuttle-shaped block having the same shape and size.
Further, referring to fig. 2, there is shown a schematic structural diagram of a first liquid crystal phase adjusting unit 2 provided in the present embodiment, where the first liquid crystal phase adjusting unit 2 includes: a glass substrate 21 and a liquid crystal 22 filled in the glass substrate, and the control unit 5 is electrically connected to both right and left sides of the glass substrate 21. The first optical path compensation unit 3 is a plate glass.
The liquid crystal light valve 4 is electrically connected to the control unit 5, the liquid crystal light valve 4 is located on a propagation path along which the projection light beam propagates along the first direction, and when the liquid crystal light valve 4 is energized, the first projection light beam S1 and the second projection light beam S2 with different phases pass through the liquid crystal light valve 4 and then become right-handed circularly polarized light or left-handed circularly polarized light in frame order.
Specifically, the liquid crystal light valve 4 may convert the projection light beam into right-handed circularly polarized light in odd frames and into left-handed circularly polarized light in even frames. Alternatively, the liquid crystal light valve 4 may convert the projection light beam into left circularly polarized light in odd frames and into right circularly polarized light in even frames.
Furthermore, the first phase retarder 6, the linear polarizer 7, the first liquid crystal phase adjusting unit 2, the first optical path compensating unit 3, and the liquid crystal light valve 4 may be adhered together by adhesion, and fixedly connected to the laser projector 1.
The working principle of the above-mentioned speckle-free laser projection apparatus is described in detail with reference to fig. 1. First, the laser projector 1 is a partially polarized laser projector having a high degree of polarization, and emits a partially polarized laser projection beam. The projection beam has high transmittance after passing through the phase retarder 6 and the first linear polarizer 7, and becomes linearly polarized light with the same polarization direction as the transmission axis of the first linear polarizer.
Since the optical axis direction of the first phase adjusting unit 2 is perpendicular to or equal to the transmission axis direction of the first linear polarizer 7, only the phase of the light after passing through the first phase adjusting unit 2 changes randomly, the polarization direction is not changed, and the direction of the light deviates from the initial direction. Thereafter, the projection beam passes through the first optical path compensation unit 3 so that the direction is converted into the initial direction again and enters the liquid crystal light valve 4. Under the action of the liquid crystal light valve 4, the projection beams with different phases are alternately converted into right-handed circularly polarized light or left-handed circularly polarized light according to frames and projected on the screen 11. The projection light beam still keeps the circular polarization state through the reflection of screen 11, and the viewer can be respectively left eye image and right eye image after wearing circular polarization glasses, realizes the separation of left eye image and right eye image to realize 3D shows.
In the embodiment of the present application, by providing the first liquid crystal phase adjusting unit 2 in the propagation path of the projection light beam, the first liquid crystal phase adjusting unit 2 has different thicknesses in the first direction in which the projection light beam propagates, and the first liquid crystal phase adjusting unit 2 receives the first voltage whose voltage value output by the control unit 5 varies randomly with time, so that the phase of coherent light on a wavefront perpendicular to the propagation direction is randomized when the projection light beam passes through the first liquid crystal phase adjusting unit 2, thereby reducing spatial coherence and eliminating speckle. By adopting the speckle-free laser projection equipment disclosed by the invention, the screen does not need to be vibrated, the screen cannot be loosened, the screen cannot absorb dust, and the reliability problem of a vibration system is solved.
Optionally, the laser projector 1, the phase retarder 6, the first linear polarizer 7, the first liquid crystal phase adjusting unit 2, the first optical path compensating unit 3, and the liquid crystal light valve 4 are fixedly connected and located in the projection light path. Therefore, the accuracy of the optical axis of each component can be guaranteed, and the 3D picture is small in serial winding and weak in ghost.
Referring to fig. 3, a schematic structural diagram of another speckle-free laser projection apparatus provided in this embodiment is shown. The projection device further includes: the second liquid crystal phase adjusting unit 8 and the second optical path compensating unit 9 are sequentially arranged on a propagation path of the projection light beam and are arranged between the first optical path compensating unit 3 and the liquid crystal light valve 4, the optical axis of the second liquid crystal phase adjusting unit 8 is perpendicular to the optical axis of the first liquid crystal phase adjusting unit 2, the second liquid crystal phase adjusting unit 8 is electrically connected with the control unit 5, the control unit 5 outputs a third voltage with a voltage value randomly changing along with time to the second liquid crystal phase adjusting unit 8, after the projection light beam passes through the second liquid crystal phase adjusting unit 8, the direction of the projection light beam is adjusted from the first direction to the third direction, the phase of the first projection light beam S1 is adjusted from the second phase to the third phase, and the phase of the second projection light beam S2 is adjusted from the third phase to the fourth phase; the second optical path compensation unit 9 is disposed on a propagation path along which the projection light beam propagates in the third direction, and after the projection light beam passes through the second optical path compensation unit 9, the direction of the projection light beam is changed from the third direction to the first direction and enters the liquid crystal light valve 4.
Because the optical axis of the second liquid crystal phase adjusting unit 8 is perpendicular to the optical axis of the first liquid crystal phase adjusting unit 2, the phase of the relevant light can be further randomized and controlled from different directions, and a better speckle eliminating effect can be obtained.
The liquid crystal light valve 4 includes a first sub-light valve 41 and a second sub-light valve 42 with their optical axes perpendicular to each other, and the optical axis of the first linear polarizer 7 is at 45 degrees or minus 45 degrees with respect to the optical axis of the first sub-light valve 41.
Referring to fig. 4 and 5, schematic diagrams illustrating relative angles of optical axes of the first linear polarizer 7, the first sub light valve 41 and the second sub light valve 42 are shown.
Referring to fig. 6, a schematic structural diagram of still another speckle-free laser projection apparatus provided in this embodiment is shown. The projection device further comprises: and a second linear polarizer 10, wherein the second linear polarizer 10 is arranged on the propagation path of the projection light beam and is arranged in front of the liquid crystal light valve 4 immediately adjacent to the liquid crystal light valve 4. The laser projector 1, the first phase delayer 6, the first linear polarizer 7, the first liquid crystal phase adjusting unit 2 and the first optical path compensating unit 3 are fixedly connected, the second linear polarizer 10 is fixedly connected with the liquid crystal light valve 4, in the first state, the second linear polarizer 10 and the liquid crystal light valve 4 are both positioned on the propagation path of the projection beam, and in the second state, the second linear polarizer 10 and the liquid crystal light valve 4 are both kept away from the propagation path of the projection beam.
The second linear polarizer 10 is added on the propagation path of the projection beam to further filter according to the polarization direction, so as to ensure low ghost in 3D playing.
Optionally, when the projection device performs a 3D projection, the liquid crystal light valve 4 is in the first state, and the liquid crystal light valve 4 receives the second voltage output by the control unit 5; when the projection device performs a 2D projection, the liquid crystal light valve 4 is in the second state. It is understood that the control unit 5 may not output the voltage to the liquid crystal light valve 4 when performing the 2D projection to save power consumption.
Alternatively, the liquid crystal light valve 4 may be switched between the inside and outside of the propagation path by a manual or electric driving manner, so as to meet different requirements of 2D projection and 3D projection.
The above description is only an example of the present invention and is not intended to limit the present invention. Various modifications and alterations to this invention will become apparent to those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.
Claims (10)
1. A speckle-free laser projection device, comprising: the laser projector comprises a laser projector (1), a first liquid crystal phase adjusting unit (2), a first optical path compensating unit (3), a liquid crystal light valve (4), a control unit (5) and a first linear polarizer (7);
the laser projector (1) is used for emitting projection beams, the projection beams comprise a first projection beam (S1) and a second projection beam (S2), and the first projection beam (S1) and the second projection beam (S2) have different heights in a paper plane;
after the projection light beam emitted by the laser projector (1) passes through the first linear polarizer (7), the projection light beam is changed into linearly polarized light which is incident according to a first direction and is incident to the first liquid crystal phase adjusting unit (2), and the optical axis of the first liquid crystal phase adjusting unit (2) is parallel to or vertical to the light transmission axis of the first linear polarizer (7);
the first liquid crystal phase adjusting unit (2) and the first optical path compensating unit (3) are sequentially arranged on a propagation path of the projection light beam; the shapes of the first liquid crystal phase adjusting unit (2) and the first optical path compensating unit (3) are both shuttle-shaped, and the vertical sections of the first liquid crystal phase adjusting unit (2) and the first optical path compensating unit (3) are both right-angled trapezoids;
the first liquid crystal phase adjusting unit (2) has different thicknesses in a first direction of propagation of the projection light beam, the first liquid crystal phase adjusting unit (2) is electrically connected with the control unit (5), the first liquid crystal phase adjusting unit (2) receives a first voltage with a voltage value randomly changing along with time, after the projection light beam passes through the first liquid crystal phase adjusting unit (2), the propagation direction of the projection light beam is adjusted from the first direction to a second direction, the phase of the first projection light beam (S1) is adjusted from a first phase to a second phase, and the phase of the second projection light beam (S2) is adjusted from the first phase to a third phase; the variation period of the first voltage is less than the human eye integration time;
the first optical path compensation unit (3) is arranged on a propagation path of the projection light beam propagating along the second direction, and after the projection light beam passes through the first optical path compensation unit (3), the propagation direction of the projection light beam is changed from the second direction to the first direction;
the liquid crystal light valve (4) is electrically connected with the control unit (5), the liquid crystal light valve (4) is positioned on a propagation path of the projection light beam along a first direction, and the control unit (5) adjusts the liquid crystal light valve (4) to enable the first projection light beam (S1) and the second projection light beam (S2) with different phases to be changed into right-handed circularly polarized light or left-handed circularly polarized light according to a frame sequence;
the emergent light of the laser projector (1) is partially polarized light with high degree of polarization, the laser projector (1) further comprises a first phase retarder (6), and the polarization direction of the polarized light of the laser projector (1) after passing through the first phase retarder (6) is the same as the direction of the light transmission axis of the first linear polarizer (7);
the polarization degree of the laser projector is larger than 80%, and the transmittance of the emergent light of the laser projector after passing through the first phase retarder (6) and the first linear polarizer (7) is larger than 81%.
2. The speckle-free laser projection apparatus according to claim 1, wherein the first liquid crystal phase adjusting unit (2) comprises: a glass substrate (21) and a liquid crystal (22) filled in the glass substrate.
3. The speckle-free laser projection device according to claim 1, further comprising at least one phase adjusting unit group consisting of a liquid crystal phase adjusting unit and an optical path length compensating unit, wherein the liquid crystal optical axis in the phase adjusting unit group is perpendicular or parallel to the first linear polarizer (7), and the phase adjusting unit group is arranged on the optical path between the first linear polarizer (7) and the liquid crystal light valve (4).
4. The speckle-free laser projection device of claim 1, wherein the liquid crystal light valve (4) comprises a first sub-light valve (41) and a second sub-light valve (42) with mutually perpendicular optical axes, and the optical axis of the first linear polarizer (7) is at 45 degrees or minus 45 degrees to the optical axis of the first sub-light valve (41).
5. The speckle-free laser projection device according to claim 1, wherein the laser projector (1), the first liquid crystal phase adjusting unit (2), the first optical path compensating unit (3), the liquid crystal light valve (4), the control unit (5) and the first linear polarizer (7) are fixedly connected; when performing both 2D and 3D projection, the liquid crystal light valve (4) is in a first state, on the propagation path of the projection beam.
6. The speckle-free laser projection device of claim 5, wherein the laser projector (1), the first linear polarizer (7), the first liquid crystal phase adjusting unit (2), the first optical path compensating unit (3) and the liquid crystal light valve (4) are sequentially bonded into a whole according to the optical path.
7. The speckle-free laser projection device of claim 6, wherein the control unit (5) is external to the whole, or internal to the laser projector (1).
8. The speckle-free laser projection device according to claim 1, further comprising a second linear polarizer (10), wherein the second linear polarizer (10) is disposed in front of the liquid crystal light valve (4) and adjacent to the liquid crystal light valve (4), the laser projector (1), the first linear polarizer (7), the first liquid crystal phase adjusting unit (2) and the first optical path compensating unit (3) are fixedly connected, and the second linear polarizer (10) and the liquid crystal light valve (4) are fixedly connected to form an optical valve assembly.
9. The speckle-free laser projection device of claim 8, wherein the light valve assembly, when in the first state, is always in the propagation path of the projection beam; when the light valve component is in the second state, the light valve component avoids the propagation path of the projection light beam.
10. The speckle-free laser projection device of claim 9, wherein, when the projection device performs 3D projection, the light valve assembly is in the first state, and the liquid crystal light valve (4) receives the second voltage output by the control unit (5); when the projection device performs 2D projection, the light valve assembly is in the second state.
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| CN100472274C (en) * | 2004-08-31 | 2009-03-25 | 东南大学 | Double refraction sinusoidal projection grating generator |
| US9063357B2 (en) * | 2007-03-20 | 2015-06-23 | Jabil Circuit, Inc. | Method for despeckling in laser display systems |
| US8395714B2 (en) * | 2009-04-16 | 2013-03-12 | Microvision, Inc. | Scanned projection system using polymerized liquid crystal layer for speckle reduction |
| CN206848599U (en) * | 2017-06-08 | 2018-01-05 | 杭州中科极光科技有限公司 | Wedge-shaped mirrors eliminate laser speckle device, LASER Light Source and laser display system |
| CN207571403U (en) * | 2017-12-04 | 2018-07-03 | 歌尔科技有限公司 | Disappear speckle device, laser light source and laser projection system |
| CN108051976A (en) * | 2017-12-29 | 2018-05-18 | 深圳市时代华影科技股份有限公司 | The laser projection device and system of speckle can be eliminated |
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