CN117348265A - Laser speckle eliminating device and projection system - Google Patents
Laser speckle eliminating device and projection system Download PDFInfo
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- CN117348265A CN117348265A CN202311428157.XA CN202311428157A CN117348265A CN 117348265 A CN117348265 A CN 117348265A CN 202311428157 A CN202311428157 A CN 202311428157A CN 117348265 A CN117348265 A CN 117348265A
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Classifications
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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
- G02F1/0136—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 for the control of polarisation, e.g. state of polarisation [SOP] control, polarisation scrambling, TE-TM mode conversion or separation
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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
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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
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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
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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
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- G03B21/208—Homogenising, shaping of the illumination light
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Abstract
The embodiment of the application provides a laser speckle eliminating device and a projection system. The laser speckle removing device comprises: the first speckle removing device and the second speckle removing device are arranged along the same optical axis; the first speckle eliminating device modulates the received laser so that the laser emitted from at least two different positions of the first speckle eliminating device has different polarization states; the second speckle eliminating device modulates the received laser so that the laser emitted from different positions of the second speckle eliminating device is diffused along different directions.
Description
Technical Field
The embodiment of the application relates to the technical field of laser display, in particular to a laser speckle eliminating device and a projection system.
Background
The laser light source projector mostly adopts an independent optical system for optical coupling, and combines laser light sources with different colors, and has the advantages of high brightness, long service life, wide color gamut, high efficiency and the like. 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.
Common means of resolving macula are: the method adopts vibration diffraction element, dynamic diffusion sheet, MEMS scanning galvanometer and other modes to superimpose speckle in the time of human eye persistence effect, so that speckle contrast is reduced due to time average, and speckle inhibition effect of devices is enhanced, but the current speckle dissipation means only can weaken speckle to a certain extent, and has the defects of system stability problem, noise problem, system volume increase and the like, so that the laser projection system has complex structure, high cost and difficult miniaturization; or the vibrating screen can achieve better speckle dissipation effect, but the cost and weight are increased, the maintenance is difficult, and the practicability is limited.
In view of the foregoing, there is a need to provide a new technical solution to solve the above-mentioned problems.
Disclosure of Invention
The purpose of the application is to provide a novel technical scheme of a laser speckle eliminating device and a projection system.
In a first aspect, the present application provides a laser speckle dissipating apparatus. The laser speckle removing device comprises: the first speckle removing device and the second speckle removing device are arranged along the same optical axis;
the first speckle eliminating device modulates the received laser so that the laser emitted from different positions of the first speckle eliminating device has different polarization states;
the second speckle eliminating device modulates the received laser so that the laser emitted from at least two different positions of the second speckle eliminating device is diffused along different directions.
Optionally, the first speckle removing device is a depolarization device.
Optionally, the first speckle removing device comprises at least two optical components configured to be able to adjust the polarization state of the laser light;
at least two optical components are adjacently arranged along the laser transmission direction;
each optical component is provided with an inclined surface, and the inclined surfaces of adjacent optical components are jointed.
Optionally, the at least two optical components include a first optical component and a second optical component, and a ratio of a maximum thickness dimension of the first optical component to a maximum thickness dimension of the second optical component is: 1:2-3, wherein the thickness direction is the transmission direction of laser.
Optionally, the first optical component has a first optical axis, the second optical component has a second optical axis, and an included angle between the first optical axis and the second optical axis ranges from: 30-50 deg.
Optionally, the optical component comprises one of a crystal, a liquid crystal, or a superlens.
Optionally, the second speckle removing device is a static diffusion sheet or a dynamic diffusion sheet.
In a second aspect, a projection system is provided. The projection system includes:
a laser unit for emitting laser;
the laser speckle removing device of the first aspect, which receives and modulates the laser light;
and the projection module is used for receiving the light modulated by the laser speckle eliminating device and modulating the modulated light into a light beam with image information to be output.
Optionally, the projection module comprises at least a dodging unit, at least one shaping unit and a projection unit;
the light homogenizing unit and the shaping unit are alternately arranged along the transmission direction of the laser;
the projection unit is used for receiving the light rays emitted from the shaping unit, modulating the received light rays into light beams with image information, outputting the light beams and imaging the light beams.
Optionally, the projection unit includes a prism, a display chip and an imaging lens;
the prism receives the light rays emitted from the shaping unit, and the light rays are transmitted to the display chip through the prism;
the display chip modulates the received light into light with image information, the display chip reflects the light with the image information, and the light with the image information is output through the prism and projected to the imaging lens for imaging.
According to an embodiment of the present application, a laser speckle dissipating device is provided. The laser speckle eliminating device enables laser to have no fixed polarization state through the first speckle eliminating device, performs depolarization treatment on the laser, and enables the laser to be diffused through the second speckle eliminating device, so that the phenomenon of mutual interference of the laser is interfered, and the problem of laser speckle can be effectively reduced through the combination of the first speckle eliminating device and the second speckle eliminating device, so that the quality of a projection picture is improved.
Other features of the present specification and its advantages will become apparent from the following detailed description of exemplary embodiments thereof, which proceeds with reference to the accompanying drawings.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the specification and together with the description, serve to explain the principles of the specification.
Fig. 1 is a diagram illustrating a first configuration of a projection system according to an embodiment of the present application.
Fig. 2 is a schematic view of a part of an optical path of a laser speckle removing device according to an embodiment of the present application.
Fig. 3 is a schematic diagram of a projection system according to an embodiment of the present application.
Fig. 4 is a diagram illustrating a third configuration of a projection system according to an embodiment of the present application.
Reference numerals illustrate:
10. a laser speckle eliminating device;
100. a laser unit;
200. a first speckle removing device; 210. a first optical member; 220. a second optical member;
300. a second speckle removing device;
400. a first light homogenizing unit; 500. a first shaping unit; 510. a first lens; 520. a second lens;
600. a second light homogenizing unit; 700. a second shaping unit; 710. a third lens; 720. a fourth lens;
800. a prism; 900. a display chip; 1000. an imaging lens.
Detailed Description
Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that: the relative arrangement of the components and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present application unless it is specifically stated otherwise.
The following description of at least one exemplary embodiment is merely exemplary in nature and is in no way intended to limit the application, its application, or uses.
Techniques and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but should be considered part of the specification where appropriate.
In all examples shown and discussed herein, any specific values should be construed as merely illustrative, and not a limitation. Thus, other examples of exemplary embodiments may have different values.
It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further discussion thereof is necessary in subsequent figures.
Embodiments of the present application provide a laser speckle dissipating device 10. Referring to fig. 1 to 4, the laser speckle removing device 10 includes: a first speckle removing device 200 and a second speckle removing device 300, the first speckle removing device 200 and the second speckle removing device 300 being disposed along the same optical axis;
the first speckle removing device 200 modulates the received laser light so that the laser light emitted from at least two different positions of the first speckle removing device 200 has different polarization states;
the second speckle removing device 300 modulates the laser received by the second speckle removing device 300, so that the laser emitted from different positions of the second speckle removing device 300 is diffused in different directions.
In the embodiment of the present application, the laser speckle removing device 10 includes a first speckle removing device 200 and a second speckle removing device 300, where the first speckle removing device 200 and the second speckle removing device 300 are disposed along the same optical axis. Referring to fig. 1, 2 and 4, the first speckle removing device 200 may be positioned in front of the second speckle removing device 300, the first speckle removing device 200 receiving the laser light emitted from the laser unit, and the second speckle removing device 300 receiving the laser light emitted from the first speckle removing device 200; alternatively, referring to fig. 3, the second speckle removing device 300 may be positioned in front of the first speckle removing device 200, the second speckle removing device 300 receiving the laser light emitted from the laser unit, and the first speckle removing device 200 receiving the laser light emitted from the second speckle removing device 300.
The first speckle removing device 200 modulates the received laser light, so that after the modulated laser light exits from different positions of the first speckle removing device 200, the laser light exiting from at least two different positions has different polarization states. The laser passes through the first speckle removing device 200, and the first speckle removing device 200 performs depolarization treatment on the laser, so that the laser emitted from at least two different positions of the first speckle removing device 200 has no fixed polarization state. That is, the first dissipative device 200 changes the ordered polarization state of the light it receives, such that the polarization state of the light exiting the first dissipative device becomes more disordered. Specifically, after the laser passes through the first speckle removing device 200, the laser has no polarization characteristic or weakens the polarization characteristic of the laser, which can cause that the lasers cannot interfere with each other and increase the diffusion angle of the laser to cause speckle superposition, thereby inhibiting the formation of laser speckle.
For example, for the R, G, B single-wavelength laser, after passing through the first speckle device 200, the phase difference or rotation angle of the light emitted from at least two different positions of the first speckle device 200 is different, so that the R, G, B single-wavelength laser has different polarization states, and the polarization degree between the single-wavelength lasers is reduced. Thus, the single-wavelength laser light emitted from the first speckle removing device 200 has no fixed polarization state, i.e., interference phenomenon between the single-wavelength laser light is weakened, and formation of laser speckle can be suppressed.
For the laser after light combination, after the laser after light combination passes through the first speckle dispersion device 200, the emergent light at least two different positions has different phase delays, so that the emergent light is changed into elliptical polarized light with different ellipticity, and the whole light source beam is synthesized in a random state, so that the emergent light is depolarized.
The second speckle removing device 300 modulates the received laser, so that after the modulated laser exits from different positions of the second speckle removing device 300, the laser exiting from different positions can be diffused towards different directions, the diffusion effect of the laser is improved, and the speckle removing effect of the laser can be further improved. Specifically, the laser passes through the second speckle removing device 300, so that the laser has a phase difference and an outgoing angle difference, and mutual interference of the laser is disturbed, so that the suppression effect of laser speckle is enhanced.
Compared with the conventional speckle removing means in the prior art, the laser speckle removing device 10 provided by the embodiment of the application modulates laser based on two aspects of laser depolarization and laser diffusion, and can enable the overall structure of the laser speckle removing device 10 to be simpler and the volume to be smaller while inhibiting laser speckle formation. The laser speckle removing device 10 according to the embodiment of the present application modulates laser light based on the principle of combining laser depolarization and diffusion of laser light, and is also completely different from the principle of speckle removing means commonly used in the prior art (that is, speckle is superimposed within the time of using the human eye persistence effect, so that the speckle contrast is reduced due to time averaging, and the speckle suppression effect of the device is enhanced).
Therefore, in the embodiment of the present application, a laser speckle removing device 10 is provided, where the laser speckle removing device 10 includes a first speckle removing device 200 and a second speckle removing device 300, and the first speckle removing device 200 and the second speckle removing device 300 modulate laser, specifically perform depolarization and diffusion treatment on the laser, so as to improve the speckle removing effect of the laser and improve the quality of a projection picture.
In one embodiment, the first speckle reduction device 200 is a depolarization device.
In this embodiment, the first speckle removing device 200 is defined, wherein the first speckle removing device 200 is a depolarizing device, wherein the depolarizing device is also referred to as depolarizing device, which is a polarizing device that changes polarized light into unpolarized light. Commonly used depolarization devices are gradient phase difference optics such as quartz wedges. For monochromatic light, when the linear polarized monochromatic light with a certain diameter passes through the achromatic depolarizer with gradient phase difference, the phase difference or rotation angle of the emergent light at different positions is different, so that the light beam has different polarization states, thereby changing the ordered state of the light beam and reducing the polarization degree of the emergent light. For the laser after light combination, the laser after light combination has different phase delays after passing through the depolarization device because of the laser with different wavelengths, so that the emergent light is changed into elliptical polarized light with different ellipticity, and the whole light source beam is synthesized in a random state, so that the emergent light is depolarized.
In this embodiment, therefore, the conventional depolarization device, e.g., the depolarization principle of the depolarization device, is used to achieve speckle dissipation of the laser light.
Optionally, an AR antireflection film is arranged on the surface of the depolarization device, so that the transmittance of the light source is improved, and the loss of light efficiency is reduced.
Optionally, the depolarization device can be in a light guide rod shape, so that the laser light source can be in a depolarization state, and the uniformity of light spots can be improved, namely, the depolarization and light homogenizing functions are combined. Thus, the laser speckle removing device 10 can be applied to a projection system, and the number of light homogenizing units can be reduced, so that the cost and the weight of the projection system can be reduced.
In one embodiment, referring to fig. 1-4, the first speckle device 200 comprises at least two optical components configured to be able to adjust the polarization state of the laser light;
at least two optical components are adjacently arranged along the laser transmission direction;
each optical component is provided with an inclined surface, and the inclined surfaces of adjacent optical components are jointed.
In this embodiment, the structure of the first speckle removing device 200 is defined. Wherein the first speckle reduction device 200 comprises at least two optical components, each of which can adjust the polarization state of the laser light. For example, the optical component may be one of a crystal, a liquid crystal, or a superlens. For example, polarized light is divided into two light rays with different polarization directions according to the polarization directions of the polarized light by utilizing the birefringence characteristics of the crystal, so that depolarization treatment of laser is realized, and laser speckles are inhibited by depolarizing the laser. For example, the polarization state of the laser passing through the liquid crystal is changed by utilizing different orientations of liquid crystal molecules in the liquid crystal, so that depolarization treatment of the laser is realized, and laser speckles are restrained by depolarizing the laser. For example, the depolarization treatment of the laser is realized by utilizing the nano structure in the super lens, and further, the laser speckle is restrained by depolarization of the laser.
In this embodiment, at least two optical members are disposed adjacently along the laser light transmitting direction, each optical member having an inclined slope, the inclined slopes of the adjacent optical members being fitted. For example, an ultraviolet curable adhesive is used between adjacent optical components. When the inclined planes of the adjacent optical components are attached, the first speckle eliminating device 200 is a depolarization device with gradient phase difference, so that no matter single-wavelength laser or combined laser passes through the first speckle eliminating device 200, the laser emitted from the first speckle eliminating device 200 can be in a depolarization state, and laser speckle formation is inhibited by depolarization.
In one embodiment, referring to fig. 1-4, at least two of the optical components include a first optical component 210 and a second optical component 220, the ratio of the maximum thickness dimension of the first optical component 210 to the maximum thickness dimension of the second optical component 220 being: 1:2-3, wherein the thickness direction is the transmission direction of laser.
In this embodiment, the ratio of the maximum thickness dimension of the first optical component 210 to the maximum thickness dimension of the second optical component 220 is defined, for example, the first optical component 210 and the second optical component 220 may be composed of two cylindrical quartz wedge crystals, wherein the thickness ratio of the thick wedge crystals to the thin wedge crystals is 2:1 to 3:1; alternatively, the first optical member 210 and the second optical member 220 may be composed of two square quartz wedge crystals, wherein the thickness ratio of the thick wedge crystals to the thin wedge crystals is 2:1 to 3:1.
In this embodiment, the range of the ratio of the maximum thickness dimension of the first optical member 210 to the maximum thickness dimension of the second optical member 220 is defined such that the first speckle reduction device 200 is a depolarization device having a gradient phase difference, so that the laser light emitted from the first speckle reduction device 200 can be made to assume a depolarization state regardless of whether the single wavelength laser light or the combined laser light passes through the first speckle reduction device 200, and laser speckle formation is suppressed by depolarization.
In one embodiment, the first optical component 210 has a first optical axis, the second optical component 220 has a second optical axis, and the included angle between the first optical axis and the second optical axis is in the range of: 30-50 deg. For example, the first speckle removing device 200 may be formed of two cylindrical quartz wedge-shaped crystals, and the optical axis angle of the two crystals may be 45 °. Wherein the man skilled in the art can define the included angle of the optical axis of the crystal in combination with the type of crystal.
In this embodiment, for example, in the case where the first optical component 210 and the second optical component 220 are both crystals, an included angle exists between the optical axis of the first optical component 210 and the optical axis of the second optical component 220, so that the first speckle removing device 200 is beneficial to better perform depolarization treatment on the laser light. Wherein the crystal optical axis: the direction in which light does not generate birefringence in an anisotropic crystal is called the direction of the optical axis of the crystal, and is simply called the crystal optical axis.
In one embodiment, the second speckle reduction device 300 is a static diffuser or a dynamic diffuser.
Specifically, the second speckle removing device 300 modulates the laser, so that the laser at the same position can be diffused along the same direction, the diffusion effect is improved, and the speckle removing effect of the laser is further improved. Specifically, the diffusion sheet can manufacture a random phase layer with a certain scattering angle on the surface of an optical material, and the structure of the diffusion sheet is honeycomb with wavelength magnitude random numbers, so that laser at the same position can be diffused along the same direction, the diffusion effect is improved, and the speckle dissipation effect of the laser is further improved.
The second speckle removing device 300 may be a static diffusion sheet, where the static diffusion sheet is that the second speckle removing device 300 is located in the laser speckle removing device 10, and the second speckle removing device 300 is not movable, i.e. not movable or not rotatable. Thus, the laser light can be diffused according to the diffusion angle formed by the static diffusion sheet, but the diffusion effect is poor.
Alternatively, the second speckle removing device 300 may be a dynamic diffusion sheet, where the second speckle removing device 300 is located in the laser speckle removing device 10, and the second speckle removing device 300 is movable by means of a driving device, i.e. movable back and forth along the optical axis, or rotatable around the optical axis. The dynamic diffusion sheet can change the vibration direction of laser to diffuse the laser so as to inhibit the formation of laser dissipation spots.
In a second aspect, a projection system is provided. Referring to fig. 1, 3 and 4, the projection system includes:
a laser unit for emitting laser;
the laser speckle removing device 10 of the first aspect, the laser speckle removing device 10 receiving and modulating the laser light;
the projection module is used for receiving the light modulated by the laser speckle eliminating device 10 and modulating the modulated light into a light beam with image information to be output.
In a specific embodiment, the laser unit includes at least two light sources and a light splitting element corresponding to each light source. The corresponding laser light is transmitted or reflected by the light-splitting element, so that the laser light spot dissipating device receives the laser light emitted from the laser unit.
In a specific embodiment, the projection module comprises at least a dodging unit, at least one shaping unit and a projection unit;
the light homogenizing unit and the shaping unit are alternately arranged along the transmission direction of the laser;
the projection unit is used for receiving the light rays emitted from the shaping unit, modulating the received light rays into light beams with image information, outputting the light beams and imaging the light beams.
In a specific embodiment, the projection unit includes a prism, a display chip, and an imaging lens;
the prism receives the light rays emitted from the shaping unit, and the light rays pass through the prism to the display chip;
the display chip modulates the received light into light with image information, the display chip reflects the light with the image information, and the light with the image information is output through the prism and projected to the imaging lens for imaging.
Referring to fig. 1, the propagation paths of the light rays are shown by arrow marks, and a laser unit 100, a first speckle removing device 200, a second speckle removing device 300, a first light homogenizing unit 400, a first shaping unit 500, a second light homogenizing unit 600, a second shaping unit 700, and a TIR (total internal reflection) prism 800 in the projection system are arranged along a first optical axis; TIR (total internal reflection) prism 800, display chip 900 (DMD (Digital Mirror Device) digital micromirror device), imaging lens 1000 are disposed along a second optical axis, the first optical axis being disposed at 45 ° to the second optical axis; the combined beam of light coming out of the laser unit 100 reaches the reflecting surface of the TIR prism 800 after passing through the first speckle removing device 200, the second speckle removing device 300, the first light homogenizing unit 400, the first shaping unit 500, the second light homogenizing unit 600 and the second shaping unit 700, the light source reaches the DMD after being reflected by the TIR prism 800, and the light source reaches the imaging lens 1000 after passing through the DMD.
In this embodiment, the projection system includes two light homogenizing units, and performs light homogenizing treatment on the laser twice, so that uniformity of the display screen can be improved.
In this embodiment, each shaping unit may be composed of two or more lenses, and the ratio of the divergence angles of the laser beam in the short axis and long axis directions may be adjusted to improve the uniformity of the light source. For example, the first shaping unit 500 includes a first lens 510 and a second lens 520, and the second shaping unit 700 includes a third lens 710 and a fourth lens 720.
In this embodiment, TIR prism 800 is a 45 rectangular prism that allows the light beam to be totally reflected at this face into the DMD, with the total reflection path occurring in the illumination path. The reflective surface of the TIR prism 800 is coated with a reflective film layer, which can improve the reflectivity of light and reduce the loss of light efficiency.
Referring to fig. 3, this embodiment differs from the projection system provided in fig. 1 in that: the arrangement positions of the first speckle removing device and the second speckle removing device are replaced in this embodiment, and in addition, in this embodiment, the first light homogenizing unit 400 is eliminated.
Referring to fig. 4, this embodiment differs from the projection system provided in fig. 1 in that: in this embodiment, the turning optical path component (prism component) uses a RTIR (reverse total internal reflection) prism 800. Referring to fig. 4, the propagation path of the light is shown by the arrow mark: the laser unit 100, the first speckle removing device 200, the second speckle removing device 300, the first light homogenizing unit 400, the first shaping unit 500, the second light homogenizing unit 600, the second shaping unit 700, the RTIR prism 800 and the display chip 900 are arranged along a first optical axis; the RTIR prism 800 and the imaging lens 1000 are arranged along a second optical axis, and the first optical axis and the second optical axis are arranged at 45 degrees; the combined beam of light from the laser unit 100 reaches the DMD after passing through the first speckle removing device 200, the second speckle removing device 300, the first light homogenizing unit 400, the first shaping unit 500, the second light homogenizing unit 600, the second shaping unit 700 and the RTIR prism 800, the light source reaches the reflecting surface of the RTIR prism 800 after passing through the DMD, and the beam of light enters the imaging lens 1000 for imaging after being reflected.
In this embodiment, RTIR prism 800 is a 45 ° right angle prism that allows the beam to be totally reflected at this face into imaging lens 1000 for imaging, with the total reflection path occurring in the imaging path. The reflective surface of the RTIR prism 800 is coated with a reflective film layer, which can improve the reflectivity of light and reduce the loss of light efficiency.
The foregoing embodiments mainly describe differences between the embodiments, and as long as there is no contradiction between different optimization features of the embodiments, the embodiments may be combined to form a better embodiment, and in consideration of brevity of line text, no further description is given here.
Although some specific embodiments of the present application have been described in detail by way of example, it should be understood by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present application. It will be appreciated by those skilled in the art that modifications may be made to the above embodiments without departing from the scope and spirit of the present application. The scope of the application is defined by the appended claims.
Claims (10)
1. A laser speckle removing device, comprising: a first speckle removing device (200) and a second speckle removing device (300), the first speckle removing device (200) and the second speckle removing device (300) being disposed along the same optical axis;
the first speckle eliminating device (200) modulates the received laser so that the laser emitted from at least two different positions of the first speckle eliminating device (200) has different polarization states;
the second speckle removing device (300) modulates the received laser so that the laser emitted from different positions of the second speckle removing device (300) is diffused in different directions.
2. The laser speckle removing device of claim 1, wherein the first speckle removing device (200) is a depolarizing device.
3. The laser speckle apparatus of claim 2, wherein the first speckle dissipating device (200) comprises at least two optical components configured to be capable of adjusting a polarization state of the laser light;
at least two optical components are adjacently arranged along the laser transmission direction;
each optical component is provided with an inclined surface, and the inclined surfaces of adjacent optical components are jointed.
4. A laser speckle reduction device according to claim 3, characterized in that at least two of the optical components comprise a first optical component (210) and a second optical component (220), the ratio of the maximum thickness dimension of the first optical component (210) to the maximum thickness dimension of the second optical component (220) being: 1:2-3, wherein the thickness direction is the transmission direction of laser.
5. The laser speckle reduction device of claim 4, wherein the first optical component (210) has a first optical axis and the second optical component (220) has a second optical axis, the angle between the first optical axis and the second optical axis ranging from: 30-50 deg.
6. The laser speckle reduction device of any one of claims 3-5, wherein the optical component comprises one of a crystal, a liquid crystal, or a superlens.
7. The laser speckle removing device of claim 1, wherein the second speckle removing device (300) is a static diffuser or a dynamic diffuser.
8. A projection system, the projection system comprising:
a laser unit (100) for emitting laser light;
the laser speckle removing device of any one of claims 1-7, which receives and modulates laser light;
and the projection module is used for receiving the light modulated by the laser speckle eliminating device and modulating the modulated light into a light beam with image information to be output.
9. The projection system of claim 8 wherein the projection module comprises at least one dodging unit, at least one shaping unit, and a projection unit;
the light homogenizing unit and the shaping unit are alternately arranged along the transmission direction of the laser;
the projection unit is used for receiving the light rays emitted from the shaping unit, modulating the received light rays into light beams with image information, outputting the light beams and imaging the light beams.
10. The projection system of claim 9, wherein the projection unit comprises a prism (800), a display chip (900), and an imaging lens (1000);
the prism (800) receives the light rays emitted from the shaping unit, and the light rays are transmitted to the display chip (900) through the prism (800);
the display chip (900) modulates the received light into light with image information, the display chip (900) reflects the light with the image information, and the light with the image information is output through the prism (800) and projected to the imaging lens (1000) for imaging.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311428157.XA CN117348265A (en) | 2023-10-30 | 2023-10-30 | Laser speckle eliminating device and projection system |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311428157.XA CN117348265A (en) | 2023-10-30 | 2023-10-30 | Laser speckle eliminating device and projection system |
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| CN117348265A true CN117348265A (en) | 2024-01-05 |
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| CN202311428157.XA Pending CN117348265A (en) | 2023-10-30 | 2023-10-30 | Laser speckle eliminating device and projection system |
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| CN (1) | CN117348265A (en) |
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- 2023-10-30 CN CN202311428157.XA patent/CN117348265A/en active Pending
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