CN111323932B - Speckle eliminating device and projection display device - Google Patents

Speckle eliminating device and projection display device Download PDF

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CN111323932B
CN111323932B CN201811532849.8A CN201811532849A CN111323932B CN 111323932 B CN111323932 B CN 111323932B CN 201811532849 A CN201811532849 A CN 201811532849A CN 111323932 B CN111323932 B CN 111323932B
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CN111323932A (en
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宋丽培
王静茹
郭汝海
刘显荣
田有良
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Qingdao Hisense Laser Display Co Ltd
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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
    • 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
    • G02F1/0009—Materials therefor
    • G02F1/0018—Electro-optical materials
    • 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 
    • G02F1/03—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 ceramics or electro-optical crystals, e.g. exhibiting Pockels effect or Kerr effect
    • G02F1/0305—Constructional arrangements
    • G02F1/0316—Electrodes
    • 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 
    • G02F1/03—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 ceramics or electro-optical crystals, e.g. exhibiting Pockels effect or Kerr effect
    • G02F1/0327—Operation of the cell; Circuit arrangements

Abstract

The embodiment of the application provides a speckle dispersing device and a projection display device, wherein the speckle dispersing device comprises: an electro-optical crystal doped with ions and a control circuit electrically connected to first and second surfaces opposed in a growth direction of the electro-optical crystal; wherein a plurality of scattering particles are present in the ion-doped electro-optic crystal; the control circuit is used for applying a voltage signal to the electro-optical crystal along the growth direction of the electro-optical crystal, so that incident light entering the electro-optical crystal is scattered under the action of the voltage signal and a plurality of scattering particles, a plurality of dynamic speckle images are generated in the emergent light direction of the electro-optical crystal, and inhibition of laser speckles is realized through superposition of the dynamic speckle images. The embodiment of the application has no mechanical loss, and the mechanical stability of the system can be ensured.

Description

Speckle eliminating device and projection display device
Technical Field
The application relates to the technical field of projection display, in particular to a speckle dispersing device and projection display equipment.
Background
As projection display devices are widely used, the display requirements of people for projection display devices are increasing. Currently, lasers are used as potential light sources for next-generation projection display devices. Because the laser is a high-coherence light source, a very serious scattering phenomenon can be generated in the display process to form laser speckles, so that the quality of laser display images is seriously influenced. Therefore, how to realize the suppression of the laser speckle is an urgent problem to be solved in the field of laser display.
At present, methods for eliminating laser speckle can be divided into two main categories in principle: the coherence of the laser light source is reduced, and the suppression of speckles is realized through the dynamic superposition of a plurality of independent and uncorrelated speckle images. The method for realizing speckle suppression through dynamic superposition of a plurality of independent uncorrelated speckle images is a common mode in the market at present. In the related art, a plurality of speckle images are generated by mechanical vibration of a scattering body, and suppression of laser speckle is realized by superposition of the plurality of speckle images. However, the mechanical vibration has the problems of abrasion of mechanical parts, influence on the stability of the system and the like.
Disclosure of Invention
The embodiment of the application provides a speckle dispersing device and projection display equipment, and solves the problems that mechanical parts are abraded due to mechanical vibration in the related art, the stability of a system is influenced and the like.
In a first aspect, the present application provides a speckle reduction device, comprising: an electro-optical crystal doped with ions and a control circuit electrically connected to first and second surfaces opposed in a growth direction of the electro-optical crystal; wherein a plurality of scattering particles are present in the ion-doped electro-optic crystal;
the control circuit is used for applying a voltage signal to the electro-optical crystal along the growth direction of the electro-optical crystal so that the incident light entering the electro-optical crystal is scattered under the action of the voltage signal and the scattering particles.
In one possible implementation, the control circuit includes: the device comprises a power supply, a first electrode and a second electrode, wherein the first electrode and the second electrode are respectively connected with the power supply;
wherein the first electrode is positioned on the first surface of the electro-optic crystal, and the second electrode is positioned on the second surface of the electro-optic crystal;
the power supply is used for applying a voltage signal to the electro-optical crystal through the first electrode and the second electrode.
In one possible implementation, the voltage amplitude and/or the modulation frequency of the voltage signal varies over time.
In one possible implementation, the speckle dissipating apparatus further includes: a deflection polarity conversion member disposed opposite to the incident surface of the electro-optical crystal;
the deflection polarity conversion component is used for deflecting the polarization direction of the incident light to the width direction of the electro-optical crystal, and the width direction of the electro-optical crystal is perpendicular to the growth direction of the electro-optical crystal and the incident direction of the incident light.
In one possible implementation, the deflection polarity conversion component includes any one of: wave plates, acousto-optic modulators or liquid crystals.
In one possible implementation, the speckle dissipating apparatus further includes: the scattering component is arranged opposite to the emergent surface of the electro-optical crystal;
the scattering component is used for carrying out light homogenizing treatment and collimation treatment on emergent light of the electro-optic crystal.
In one possible implementation, the electro-optic crystal includes any one of: potassium dihydrogen phosphate crystal KDP, potassium tantalate niobate KTN crystal, and potassium dideuterium phosphate crystal DKDP.
In one possible implementation, the ions include: anions or metal ions.
In one possible implementation, the anion comprises at least one of: SO (SO) 4 2- 、NO 3 - 、 Cl - 。
In one possible implementation, the concentration of ions doped in the electro-optic crystal is in the range of 1000 × 10 -6 ～2000×10 -6 ppm/mol。
In a second aspect, the present application provides a projection display device, comprising: a laser light source and a speckle dissipating apparatus as described in any one of the above first aspects.
In an speckle dispersing device and a projection display apparatus provided by embodiments of the present application, the speckle dispersing device includes: an electro-optical crystal doped with ions and a control circuit electrically connected to first and second surfaces opposed in a growth direction of the electro-optical crystal; wherein a plurality of scattering particles are present in the ion-doped electro-optic crystal; the control circuit is used for following in the growth direction of electro-optic crystal to the voltage signal is applyed to the electro-optic crystal, make voltage signal with under the effect of a plurality of scattering particles, to incidenting incident light in the electro-optic crystal scatters, thereby the emergent light direction of electro-optic crystal produces a plurality of dynamic speckle images, through the stack of a plurality of dynamic speckle images has realized the suppression to the laser speckle. Therefore, compared with the mode of generating a plurality of speckle images through the mechanical vibration of the scatterer in the related art, the speckle dispersing device provided by the embodiment of the application has no mechanical loss, and can ensure the mechanical stability of the system.
Drawings
Fig. 1 is a schematic diagram of a refractive index ellipsoid coordinate system of KDP provided in this embodiment;
fig. 2 is a schematic structural diagram of a KDP provided in this embodiment;
FIG. 3 is a graph showing a related art method of doping KN0 with different concentrations 3 A schematic diagram of the light scattering effect of the temporal KDP;
FIG. 4 is a schematic structural diagram of a speckle dissipating apparatus according to an embodiment of the present disclosure;
FIG. 5 is a schematic structural view of a plaque dissipation device according to another embodiment of the present disclosure;
FIG. 6 is a schematic illustration of a plaque dissipating device according to another embodiment of the present application;
FIG. 7 is a schematic illustration of a plaque dissipating device according to another embodiment of the present application;
fig. 8 is a schematic structural diagram of a projection display device according to an embodiment of the present application.
Detailed Description
First, an application scenario and a part of vocabulary related to the embodiments of the present application will be described.
As the display requirements of projection display devices are increasing (e.g., high brightness, high saturation, and/or wide area display, etc.), lasers are used as potential light sources for next generation projection display devices. Because laser is a coherent light source, a very serious scattering phenomenon can be generated in the display process to form laser speckles, so that the quality of laser display images is seriously influenced. Therefore, how to realize the suppression of the laser speckle is an urgent problem to be solved in the field of laser display.
The speckle dispersing device and the projection display device provided by the embodiment of the application comprise: an electro-optical crystal doped with ions and a control circuit electrically connected to first and second surfaces opposed in a growth direction of the electro-optical crystal; wherein a plurality of scattering particles are present in the ion-doped electro-optic crystal; the control circuit is used for following in the growth direction of electro-optic crystal to the voltage signal is applyed to the electro-optic crystal, make voltage signal with under the effect of a plurality of scattering particles, to incidenting incident light in the electro-optic crystal scatters, thereby the emergent light direction of electro-optic crystal produces a plurality of dynamic speckle images, through the stack of a plurality of dynamic speckle images has realized the suppression to the laser speckle.
The electro-optic crystal referred to in the embodiments of the present application may include, but is not limited to, any one of the following: potassium dihydrogen phosphate crystals (KDP), Potassium tantalate niobate (KTa1-xNbxO3, KTN) crystals, and Potassium dideuterium phosphate crystals (DKDP).
The electro-optical crystal related in the embodiment of the application has stable electro-optical effect and is widely applied to the fields of electro-optical scanning devices, optical switches and the like. The electro-optic effect of the electro-optic crystal is divided into a longitudinal electro-optic effect and a transverse electro-optic effect.
1) Since the direction of the electric field applied in the longitudinal electro-optical effect is consistent with the laser propagation direction, transparent electrodes need to be installed on two sides of the electro-optical crystal along the laser propagation direction, the half-wave voltage in the longitudinal electro-optical effect is high, the circuit control cost is greatly increased, and the application to display equipment (such as a laser television) is not facilitated.
2) Because the transverse electro-optical effect is that the direction of an applied electric field is vertical to the propagation direction of laser, electrodes can be arranged on two sides of the electro-optical crystal in the vertical direction of the propagation direction of the laser, and half-wave voltage can be greatly reduced by increasing the ratio of the light transmission length of the electro-optical crystal to the thickness of the electro-optical crystal.
In one aspect, embodiments of the present application relate to electro-optic crystals having a property that the refractive index changes with a change in an applied electric field. For example, the path of light scattered in the electro-optical crystal is changed due to the change of the refractive index of the electro-optical crystal, so that the change of the emergent light field is caused; on the other hand, when an electric field is applied to the electro-optical crystal, ions and holes in the electro-optical crystal also drift along with the electric field, so that not only the refractive index is changed, but also the scattering transmission of light is changed, and a dynamic scattering field is generated in the emergent light direction.
KDPs referred to in the examples of this application are typically uniaxial crystals. Fig. 1 is a schematic diagram of a refractive index ellipsoid coordinate system of a KDP provided in this embodiment, as shown in fig. 1, a coordinate axis of a refractive index ellipsoid of the KDP is along directions x1 and x2, and another coordinate axis x3 (not shown in fig. 1) is perpendicular to a plane x1-x 2. If an electric field is applied along the coordinate axis x3, the index ellipsoid of KDP is deformed, and the principal axis of the index ellipsoid is rotated 45 degrees around x3 (as shown in the coordinate axes x1 'and x 2' in fig. 1), and the rotation angle is independent of the electric field intensity.
Therefore, when the transverse electro-optic effect of KDP is used to change the refractive index, as shown in fig. 2 (fig. 2 is a schematic structural diagram of KDP provided by this embodiment), it is necessary to cut KDP by rotating KDP by 45 degrees around x3 axis (i.e. growth direction or thickness direction of KDP), that is, the length direction of KDP is 45 degrees with respect to the coordinate axis x2 direction, and the width direction of KDP is 45 degrees with respect to the coordinate axis x1 direction, so that the incident light propagates along the x 2' direction (or length direction) (the direction of the applied electric field is still along the coordinate axis x3 direction).
As shown in fig. 2, when the incident laser light is incident and propagated along the coordinate axis x2 '(i.e. the length direction of KDP), the polarization direction of the incident laser light is along the coordinate axis x 1' (i.e. the width direction of KDP), and the direction of the electric field generated by the applied voltage signal (e.g. the coordinate axis x3) is perpendicular to the propagation direction of the incident laser light, the refractive index of the electro-optical crystal is modulated by the electric field, which is expressed as:
Figure BDA0001906129470000041
wherein, n' 2 Is the changed refractive index, n 0 Is the medium linear refractive index, E is the electric field strength applied along the coordinate axis x3, γ 63 Is the linear electro-optic coefficient of the electro-optic crystal.
It can be seen that the refractive index of the electro-optic crystal changes with the strength of the electric field.
When the light transmission length of the electro-optical crystal (i.e. the length of the electro-optical crystal in the x 2' direction) is L, the phase delay of the emergent light field is:
Figure BDA0001906129470000051
where λ is the wavelength.
E.g. in KDP n 0 Is 1.51, gamma 63 For example, the applied voltage may vary by a phase of pi between 0 to 150V, with a thickness of 11.98e-12m/V, L-26.8 mm and a KDP thickness of 2.5 mm.
On the other hand, the growth of the electro-optical crystal is accompanied by the addition of dopants, e.g. Fe 3 +, Na +, Ethylene Diamine Tetraacetic Acid (EDTA), NO3-, pyrophosphate and the like, the electro-optic crystal related to the embodiment of the application can generate scattering particles, mainly macromolecules such as EDTA and polyphosphate, and accordingly a dynamic scattering field can be generated in the emergent light direction.
When the concentration of the dopant is a certain degree, these inorganic or organic substances affect the normal growth state of the crystal during the growth of the electro-optical crystal, and may agglomerate into scattering particles (with a size of several nanometers to several hundred nanometers) under the conditions of concentration, growth temperature, etc., or cause the wedge of the electro-optical crystal.
Illustratively, the distribution of scattering particles in an electro-optic crystal varies with the doping concentration and the crystal growth environment.
The doped ions referred to in the embodiments of the present application may include, but are not limited to: anions or metal ions.
Illustratively, the anions referred to in the embodiments of the present application may be, but are not limited to, at least one of the following: SO (SO) 4 2- 、 NO 3 - 、Cl - 。
Illustratively, the metal ions referred to in the embodiments of the present application may be, but are not limited toAt least one of: fe 3 +、Na+。
The ion-doped electro-optic crystal in the embodiment of the application generates a plurality of scattering particles, so that the scattering effect can be generated on the incident laser.
Defects are generated in the electro-optic crystal due to anion doping, the more defects are in the crystal, and the moving range of the defects is increased along with the increase of the crystal defects under the action of an electric field. Thus, an anion-doped electro-optic crystal is more electrically conductive than an undoped electro-optic crystal.
In addition, anions, holes and defects move under the action of an electric field, and dynamic scattered light is also generated.
It is necessary to control the concentration of the dopant ions in consideration that the quality of the electro-optic crystal is degraded after the electro-optic crystal dopant ions generate scattering particles. For example, when the concentration of the doping ions reaches a certain level, on one hand, the electro-optical crystal is cracked or cracked; on the other hand, doping ions also lowers the optical power threshold of the electro-optic crystal.
Table 1 shows K at various doping concentrations for KDP transmittance provided in the related art 2 SO 4 The transmittance table for different wavelengths. As shown in table 1: when the concentration is 1000ppm/mol, the transmittance of KDP in a visible wave band can reach about 90% when the thickness is 1 cm; the optical power threshold of the undoped KDP is 50J/cm 2 On the left and right sides, after doping anions, the optical power threshold is reduced, and the higher the anion concentration is, the lower the optical power threshold is; about 1000ppm/mol, the light damage threshold value can be ensured to be 20J/cm 2 Left and right.
Table 1 shows K at various doping concentrations for KDP transmittance provided in the related art 2 SO 4 Transmittance table for lower wavelength
Figure BDA0001906129470000061
Based on the information provided in the related art: a) the density of scattering particles in pure KTN crystals is 10 4 /cm 3 And no obvious scattering phenomenon occurs. b) Due to the fact thatThe electro-optic crystal doping affects the crystal quality, so the doping concentration needs to generate scattering on the premise of ensuring the crystal quality. With anion SO 4 2- Doping as an example, when the anion SO 4 2- Concentration of<500×10 -6 No crack at ppm; when anion SO 4 2- Concentration of 800 × 10 -6 When the patient is in a normal state, the patient has two vertebral tips without cracks; when anion SO 4 2- Concentration of 2000 × 10 -6 A small amount of cracks are generated; when anion SO 4 2- Concentration of 5000 × 10 -6 Cracks were evident. Therefore, the doping concentration should be less than 2000 × 10 -6 Within the range to ensure the crystal is crack free.
Illustratively, when SO 4 2- 、NO 3 - 、Cl - The concentration of three anions reaches 1000X 10 -6 Obvious scattering phenomenon is generated after ppm/mol; when SO 4 2- 、NO 3 - 、Cl - The concentration of three anions is less than 1000 x 10 -6 At ppm/mol, no scattering phenomenon is observed. Therefore, to generate significant scattering, the doping concentration needs to be high>1000×10 -6 ppm/mol。
The electro-optic crystal doping also affects the extinction coefficient, scattering coefficient, and absorption coefficient of the electro-optic crystal. Illustratively, the electro-optic crystal with the thickness of 2mm is taken as an example, the speckle field generated by the extinction coefficient, the scattering coefficient and the absorption coefficient is subjected to simulation calculation, and the calculation result shows that when the doping concentration is 1000 multiplied by 10 -6 The ppm/mol is increased to 2500X 10 -6 In the process, the transmittance of the electro-optic crystal is reduced by 0.7%, and the speckle contrast is reduced by about 15% (under the condition of no voltage dynamic driving). Therefore, the concentration range of 1000X 10 can be ensured under the premise of ensuring the quality of the electro-optical crystal -6 ppm/mol～2000×10 -6 The doping concentration is as high as possible between ppm/mol.
The concentration of ions doped in the electro-optic crystal referred to in the embodiments of the present application may range from 1000 x 10 -6 ～2000×10 -6 ppm/mol。
FIG. 3 is a graph showing a related art method of doping KN0 with different concentrations 3 And (3) a schematic diagram of the light scattering effect of KDP. As shown in figure 3 of the drawings,(a) the light scattering effect of KDP is shown as a schematic diagram when the concentration is 0ppm/mol, (b) the light scattering effect of KDP is shown as a schematic diagram when the concentration is 100ppm/mol, (c) the light scattering effect of KDP is shown as a schematic diagram when the concentration is 1000ppm/mol, and (d) the light scattering effect of KDP is shown as a schematic diagram when the concentration is 10000 ppm/mol; wherein the spots in the picture are scattering particles, the size is in the nanometer or micrometer scale, and the spots are not macroscopically seen, so the spots should be non-uniform.
The technical solution of the present application will be described in detail below with specific examples. The following several specific embodiments may be combined with each other, and details of the same or similar concepts or processes may not be repeated in some embodiments.
Fig. 4 is a schematic structural diagram of a speckle dispersing device according to an embodiment of the present disclosure. As shown in fig. 4, the speckle dispersing device provided by the present embodiment may include: an ion-doped electro-optical crystal 1 and a control circuit 2 electrically connected to a first surface 1a and a second surface 1b opposite in a growth direction of the electro-optical crystal (e.g., a direction of a coordinate axis x 3).
Illustratively, the first surface 1a of the electro-optical crystal 1 and the second surface 1b of the electro-optical crystal 1 are both parallel to the length direction of the electro-optical crystal 1 (or the transmission direction of incident light).
Illustratively, the electro-optic crystal 1 may include, but is not limited to, any of: KDP, KTN crystals, DKDP.
Illustratively, the ions doped in the electro-optical crystal 1 may include, but are not limited to: anions (e.g. SO) 4 2- 、NO 3 - And/or Cl - Etc.) or metal ions (e.g., Fe) 3 + and/or Na +, etc.).
In order to ensure the quality of the electro-optical crystal 1, the concentration of ions doped in the electro-optical crystal 1 may be in the range of 1000 × 10 -6 ～2000×10 -6 ppm/mol。
Since the electro-optical crystal 1 is doped with ions, a plurality of scattering particles are generated in the electro-optical crystal 1, so that the scattering effect can be generated on the incident laser. Wherein the amount and/or size of the scattering particles affects the degree of scattering.
Illustratively, the control circuit 2 is configured to apply a voltage signal to the electro-optical crystal 1 in a growth direction (or a thickness direction) of the electro-optical crystal 1, so that incident light incident into the electro-optical crystal is scattered by the voltage signal and the plurality of scattering particles.
In the embodiment of the present application, a voltage signal is applied to the electro-optical crystal 1 by the control circuit 3 along the growth direction (or thickness direction, i.e. perpendicular to the transmission direction of the incident light, for example, the direction of coordinate axis x3) of the electro-optical crystal 1, so as to form an electric field in the growth direction of the electro-optical crystal 1, on one hand, the refractive index of the electro-optical crystal 1 is changed under the action of the electric field, so that the path of the incident light scattered in the electro-optical crystal 1 is changed, and thus the dynamic change of the emergent light field is caused; on the other hand, under the action of the plurality of scattering particles, a scattering effect can be generated on the incident light; therefore, a plurality of dynamic speckle images are generated in the emergent light direction of the electro-optical crystal 1, and the laser speckles are suppressed by superposing the dynamic speckle images.
Illustratively, the strength of the electric field involved in the embodiments of the present application may be approximately equal to the ratio of the voltage value of the voltage signal to the thickness value of the electro-optical crystal 1.
Illustratively, the voltage amplitude and the modulation frequency of the voltage signal applied to the electro-optical crystal 1 for generating the electric field involved in the embodiments of the present application influence the dynamic scattering process. Wherein the voltage amplitude determines the amplitude of the refractive index change; the modulation frequency determines how fast the dynamic speckle image changes.
Illustratively, the voltage amplitude and/or the modulation frequency of the voltage signal applied to the electro-optical crystal 1 for generating the electric field change with time in the embodiments of the present application, so that the refractive index of the electro-optical crystal 1 changes continuously, and holes and defects also move accordingly to generate a dynamic scattered field in combination, which can further increase the effect of suppressing laser speckle.
For example, the voltage signals involved in the embodiments of the present application may include, but are not limited to: a periodic voltage signal (e.g., a positive selection wave voltage signal, etc.) and/or a random voltage signal.
For example, when the voltage signal referred to in the embodiments of the present application is a periodic voltage signal, the period of the periodic voltage signal may be equal to the exposure time period of the display screen observer side in the projection display device. For example, if observed by the human eye, the period of the periodic signal may be 1/24 seconds or less.
The plaque dissipation device provided by the embodiment of the application comprises: an electro-optical crystal doped with ions and a control circuit electrically connected to first and second surfaces opposed in a growth direction of the electro-optical crystal; wherein a plurality of scattering particles are present in the ion-doped electro-optic crystal; the control circuit is used for following in the growth direction of electro-optic crystal to the voltage signal is applyed to the electro-optic crystal, make voltage signal with under the effect of a plurality of scattering particles, to incidenting incident light in the electro-optic crystal scatters, thereby the emergent light direction of electro-optic crystal produces a plurality of dynamic speckle images, through the stack of a plurality of dynamic speckle images has realized the suppression to the laser speckle. Therefore, compared with the mode of generating a plurality of speckle images through the mechanical vibration of the scatterer in the related art, the speckle dispersing device provided by the embodiment of the application has no mechanical loss, and can ensure the mechanical stability of the system.
Fig. 5 is a schematic structural diagram of a speckle dispersing device according to another embodiment of the present application. On the basis of the above embodiments, the present application describes an implementation manner of the control circuit 2. As shown in fig. 5, in the embodiment of the present application, the control circuit 2 may include: a power source 21 and a first electrode 22 and a second electrode 23 connected to the power source 21, respectively.
The first electrode 22 is located on the first surface 1a of the electro-optical crystal 1, and the second electrode 23 is located on the second surface 1b of the electro-optical crystal 1, so that the power supply 21 applies a voltage signal to the electro-optical crystal through the first electrode 22 and the second electrode 23 along the growth direction of the electro-optical crystal, so as to form an electric field in the growth direction of the electro-optical crystal, and thus the refractive index of the electro-optical crystal 1 changes under the action of the electric field, so that the path of the incident light scattered in the electro-optical crystal 1 changes, and thus a scattering effect can be generated on the incident light, and suppression of laser speckle is achieved.
Of course, the control circuit 3 may also adopt other realizations, which is not limited in the embodiment of the present application.
FIG. 6 is a schematic view of a plaque dissipation device according to another embodiment of the present application. On the basis of the above embodiments, as shown in fig. 6, the speckle dispersing device provided in the embodiments of the present application may further include: and a deflection polarity conversion member 3 disposed to face the incident surface 1c of the electro-optical crystal 1.
Illustratively, the polarization conversion component 3 is configured to deflect the polarization direction of the incident light to a width direction (e.g., a direction of a coordinate axis x1 ') of the electro-optical crystal 1, wherein the width direction of the electro-optical crystal is perpendicular to a growth direction (e.g., a coordinate axis x3) of the electro-optical crystal and an incident direction (e.g., a coordinate axis x 2') of the incident light, so as to avoid a birefringence phenomenon during the transmission of laser light.
Illustratively, the deflection polarity conversion part 3 may include, but is not limited to: wave plates, acousto-optic modulators or liquid crystals; of course, other components with properties of changing the deflection of incident light may be included, which is not limited in the embodiments of the present application.
Alternatively, a polarizing member (e.g., a polarizing plate) may be provided between the laser light source for generating the incident light and the deflection polarity conversion member 3. If the polarization direction of the incident light itself is parallel to the width direction of the electro-optical crystal 1, it is not necessary to provide a polarizing member between the laser light source and the polarization conversion member 3.
FIG. 7 is a schematic diagram of a plaque dissipation device according to another embodiment of the present application. On the basis of the above embodiments, as shown in fig. 7, the speckle dispersing device provided in the embodiments of the present application may further include: and a scattering member 4 disposed opposite to the emission surface 1d of the electro-optical crystal 1.
Illustratively, the scattering component 4 is used for performing light homogenizing treatment and collimating treatment on the emergent light of the electro-optical crystal 1, so that a dynamic scattering effect can be enhanced, and an inhibition effect of laser speckle can be improved.
Illustratively, the scattering component 4 may include, but is not limited to: an engineered diffuser; of course, other devices with functions of light homogenizing and collimating can be included, which is not limited in the embodiments of the present application.
Fig. 8 is a schematic structural diagram of a projection display device according to an embodiment of the present application. As shown in fig. 8, a projection display device 80 provided in the embodiment of the present application may include: a laser source 801 and a speckle dissipating apparatus 802.
The speckle removing device 802 may adopt the structure in the above embodiments of the speckle removing device of the present application, and its implementation principle and technical effect are similar, which are not described herein again.
Of course, the projection display device 80 may also include other components, which are not limited in the embodiments of the present application.
In the foregoing embodiments, the descriptions of the respective embodiments have respective emphasis, and for parts that are not described in detail in a certain embodiment, reference may be made to related descriptions of other embodiments.
It will be appreciated that the relevant features of the devices described above may be referred to one another. In addition, "first", "second", and the like in the above embodiments are for distinguishing the embodiments, and do not represent merits of the embodiments.
Those skilled in the art will appreciate that the components of the apparatus of the embodiments may be adapted and arranged in one or more arrangements different from the embodiments. The components of the embodiments may be combined into one component and, in addition, they may be divided into a plurality of sub-components. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and all of the components of any apparatus so disclosed, may be combined in any combination, except combinations where at least some of such features are mutually exclusive. Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise.
The above description is only for the specific embodiments of the present application, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present disclosure, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.
Finally, it should be noted that: the above embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present application.

Claims (11)

1. A speckle-resolving device, comprising: an electro-optical crystal doped with ions and a control circuit electrically connected to first and second surfaces opposed in a growth direction of the electro-optical crystal; wherein a plurality of scattering particles are present in the ion-doped electro-optic crystal, the ion-doped electro-optic crystal including a defect;
the control circuit is used for applying a voltage signal to the electro-optical crystal along the growth direction of the electro-optical crystal, the ions and the defects dynamically move to generate dynamic scattered light, and the incident light entering the electro-optical crystal is scattered under the action of the voltage signal and the scattering particles.
2. The apparatus of claim 1, wherein the control circuit comprises: the device comprises a power supply, a first electrode and a second electrode, wherein the first electrode and the second electrode are respectively connected with the power supply;
wherein the first electrode is positioned on the first surface of the electro-optic crystal, and the second electrode is positioned on the second surface of the electro-optic crystal;
the power supply is used for applying a voltage signal to the electro-optical crystal through the first electrode and the second electrode.
3. The apparatus of claim 1, wherein the voltage amplitude and/or modulation frequency of the voltage signal varies over time.
4. The apparatus of any of claims 1-3, further comprising: a deflection polarity conversion member disposed opposite to the incident surface of the electro-optical crystal;
the deflection polarity conversion component is used for deflecting the polarization direction of the incident light to the width direction of the electro-optical crystal, and the width direction of the electro-optical crystal is perpendicular to the growth direction of the electro-optical crystal and the incident direction of the incident light.
5. The method of claim 4, wherein the deflection polarity conversion component comprises any one of: wave plates, acousto-optic modulators or liquid crystals.
6. The apparatus of any of claims 1-3, further comprising: the scattering component is arranged opposite to the emergent surface of the electro-optical crystal;
the scattering component is used for carrying out light homogenizing treatment and collimation treatment on emergent light of the electro-optic crystal.
7. The apparatus of any of claims 1-3, wherein the electro-optic crystal comprises any of: potassium dihydrogen phosphate crystal KDP, potassium tantalate niobate KTN crystal, potassium dideuterium phosphate crystal DKDP.
8. The apparatus of any one of claims 1-3, wherein the ions comprise: anions or metal ions.
9. The apparatus of claim 7, wherein the anions comprise at least one of: SO (SO) 4 2- 、NO 3 - 、Cl - 。
10. A device according to any of claims 1-3, wherein the concentration of ions doped in the electro-optic crystal is in the range 1000 x 10 -6 ～2000×10 -6 ppm/mol。
11. A projection display device, comprising: a laser light source and the speckle dissipating apparatus of any one of claims 1-10.
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