CN102193208B - Speckle reduces device and speckle reduces mask - Google Patents

Abstract

Disclose a kind of speckle and reduce device and speckle minimizing mask.Speckle reduces device (1) and including: radiation path；And the mask (7) being arranged in radiation path, mask (7) includes the electrically controllable cellular array being configured to be formed time dependent pattern on mask.Speckle reduces mask (7) and including: the first linear array, and it includes the first parallel lines being arranged to change the phase place of incident radiation；And include that the second linear array of the second parallel lines, the second parallel lines are arranged to change the phase place of incident radiation and also are arranged such that to be formed in the intersection of the first parallel lines and the second parallel lines unit.Speckle reduces mask (7) and including: according to formula A^TA=β δ_{K, l}The N formed₁×N₂Cell array A, wherein, A^TBeing the transposition of A, β is positive real constant, δ_{K, l}It is kronecker delta, N₁≠N₂。

Description

Speckle reduces device and speckle reduces mask

Technical field

The present invention relates to the minimizing of speckle, irradiate especially for laser, such as laser display system.

Background technology

Speckle is caused by the interference of light occurred from screen.As shown in fig. 1, the existence of speckle cause graininess pattern and Can occlusion image be formed.

The source of this graininess pattern is screen surface the most coarse on the yardstick of incident (such as optics) wavelength.? Under the irradiation of coherent radiation (such as laser), the ripple reflected from this surface includes the composition from many independent scattering regions.This The propagation of reflection light distally observation station causes having these of relative delay (can be from several wavelength change to many wavelength) The increase of various scattering components.The interference of small echo the most relevant after these phase shifts causes being known as speckle (speckle) Graininess pattern.Specifically, the interference small echo that rises mutually causes speck；Destructive interference small echo causes skin dark stain；Part rises mutually and interferes and portion Destructive interference small echo is divided to cause centre or greyness.

For the picture quality in improving laser display system or other system any of speckle being run into, it is necessary to subtract Few marbled effect.Contrast (CR) can be passed through and measure or calculate the amount of speckle: CR=σ/I, wherein, I is mean intensity, σ It it is root-mean-square strength fluctuation.Can be by the accumulated time (integration of the detector (such as human eye) at viewing image Time) produce some independent speckle pattern in and make them reach averagely to reduce speckle.Can be by accumulated time The N number of independent speckle pattern of superposition makes speckle contrast degree reduce extremelyCan reduce by using vibrosieve to realize speckle. But, this technology is owing to needs high power actuator is without the most practical.Can also be such as by using such as laser array Or multiple sources of wideband laser, at irradiation source, reduce speckle.But, the laser array of particular design can correspondingly increase Cost.

US2004/0008399 describes by using Ha Dema (Hadamard) matrix (HM) phase mask as diffusion Device (being positioned in intermediate image plane) produces N number of independent speckle pattern to the method suppressing speckle.Vitreous silica plate etches Big HM phase mask, and make it mechanically move subsequently, to produce different speckle pattern at screen when laser beam passes. But, the mechanical part needed in this approach limits technology and is unpractical, particularly when introducing high-order HM to realize When the speckle of higher degree reduces.Use mechanical vibration, need the actuator that operating frequency is high, oscillation distances is bigger.

Accordingly, it would be desirable to overcome the speckle minimizing technology of these problems.

Summary of the invention

According to first aspect, it is provided that a kind of speckle reduces device, comprising: radiation path；And it is arranged in radial road Mask in footpath, mask includes the electrically controllable cellular array being configured to be formed time dependent pattern on mask.Often The electric control of individual unit eliminate make to need not generally mechanical with identical with the accumulated time of detector or ratio faster speed The mobile mask in ground, but change pattern.In other words, mask can keep fixing or static about the radiation path used.Radiation Can be the light of any wavelength, including such as radio wave, microwave and ultraviolet ripple.Specifically, speckle can from laser instrument or Other coherent source occurs.Radiation can also is that sound wave and the ultrasonic radiation e.g. used in ultra sonic imaging.

Preferably, during pattern can be phase pattern and intensity pattern.Owing to speckle is that phase effect causes, So the phase pattern on mask can be particularly advantageous.

Preferably, mask can be arranged to fix about radiation path.This reduces the needs of mobile parts further.

Alternatively, cellular array can include the row that number is different from column number.In other words, mask can include any Any number of unit and can be non-square.This has special benefit, and this more flexible mask can be with range site The limited step change of state realizes higher theoretical speckle suppression (can be by the imaging len of detector and the number of projecting lens Value aperture determines).

Advantageously, this device can also include: the electrode can being connected between controller and each unit in mask. Other type of electrical connection can be carried out.

Preferably, speckle minimizing device can also include: connects the electrodes to the control bus of controller.

Alternatively, speckle minimizing device can also include: two or more masks.It is, for example possible to use two, four Individual, six, eight or more mask.Multiple masks can form compound single mask or be connected in radiation or light path Ground is placed, i.e. superposed on one another or covering (partially or even wholly).There are two or more masks and can reduce the electricity of unit Control and the demand of electrode and number.These multiple masks can have linear array or other types of patterns.

Alternatively, mask can be formed by the first linear array and the second linear array.This reduce further electric control with And the demand of electrode.Other linear array can also be used, including three to eight or more, and preferably four, Six or eight arrays.Linear array can be by the line closely compressed, or specifically, between same size very close to each other Adjacent lines is formed.

Preferably, the first array can include that the first parallel lines, the second array can include being arranged to and the first parallel lines Become the second parallel lines of non-zero angle.Therefore, the first parallel lines will intersect or intersect with the second parallel lines (in radiation path). Non-zero angle can from 0 to 90 ° (such as, at 60 ° or four masks are at 45 ° for three masks, or such as Anywhere Other angle any or mask count), to form difform mask, it is preferred that be at 90 °, to form square Or rectangular mask.

Preferably, each parallel lines can be arranged to selectively change the phase place of incident radiation.Therefore, incident radiation The final phase change run into by be at each phase-plate phase change and.

Preferably, electrically controllable unit can be formed in the intersection between the first parallel lines and the second parallel lines.

Preferably, the second parallel lines can be arranged to substantially vertical with the first parallel lines.

Alternatively, the second linear array can contact with the first linear array and be superimposed upon on the first linear array. However, it is possible to make two (or more) linear arraies separately.As an alternative, can exist and make separate one or more of linear array Multiple additional optical elements.

Preferably, speckle minimizing device can also include: each line of the first parallel lines is connected to the first of controller Control bus and each line of the second parallel lines is connected to the second control bus of controller.As an alternative, single controller May be used for all line or belts.

Preferably, the gross phase through the radiation of each unit of mask changes is 0 or π radian.Mask by two (or More) in the case of discrete mask formed, intersecting or at unit, phase change will be two (or more) independent phase place The sum changed.Such as, in the intersection of two lines of the phase change each with π radian, gained phase change will be 2 π ( Termination fruit or 0), or transmitted radiation will with incident radiation in phase place opposing.In another example, horizontal line can have There is π phase change, but the vertical curve intersected with horizontal line can have 0 phase change.In this case, final phase change Would is that π.

Alternatively, mask can be transmission mask or reflection mask.

Preferably, the unit of electrically controllable cellular array has two states.Such as, change to come thoroughly with 0 and π radian phase Penetrate or reflect.

Preferably, the pattern on time dependent mask includes Ha Dema matrix or orthogonal array.Owing to they are than it Its pattern (particularly random pattern) every (detector or eyes) accumulated time needs less change, so these are special Effective and efficient pattern.

Alternatively, mask can be formed by the material selected from lower group, and this group is by pottery, para-electric, quartz and glass structure Become.Other material can also be suitable.

Preferably, speckle minimizing device can also include: the beam expander being arranged in radiation path.

Preferably, the intermediate image plane in mask can be located substantially on optics or radiation path or focal point.Specifically Ground, this focus such as can be in the projecting lens of display system.

According to second aspect, it is provided that a kind of speckle reduces mask, comprising: the first linear array, it includes being arranged Become to change the first parallel lines of the phase place of incident radiation；And second linear array, it includes being arranged to change incident radiation Phase place and also be arranged such that the intersection of the first parallel lines and the second parallel lines formed unit the second parallel lines. Such as, the first parallel lines can become non-zero angle with the second parallel lines.

Preferably, the phase change of each parallel lines can be independent and electrically controllable.

Preferably, the angle that the first parallel lines can be in 90 ° with the second parallel lines.However, it is possible to use other angle.

Preferably, the gross phase through the radiation of each unit of mask changes can be in 0 or π radian.

Alternatively, unit can be arranged to form the phase pattern generated from orthogonal array.Ha Dema matrix just can be Hand over a particular form of array.

Alternatively, the second linear array can contact with the first linear array and be superimposed upon on the first linear array.

Preferably, speckle minimizing mask can also include: to the electrical connection of each parallel lines.The use phase of parallel line or belt Than the total needs decreasing electrical connection for there are the needs of two-dimensional mask of many individual units.

According to the third aspect, it is provided that a kind of speckle reduces mask, comprising: the N formed according to equation below₁×N₂Single Element array A

A^TA=β δ_{K, l},

Wherein, A^TBeing the transposition of A, β is positive real constant, δ_{K, l}It is kronecker delta (Kronecker delta), N₁≠ N₂。

Preferably, it is possible between two states, control each unit in array.

Preferably, each state in two states is the phase change of incident radiation.

Alternatively, cellular array can be formed by two or more linear arraies.

Preferably, speckle reduces mask and can be arranged to be formed the time variation diagram case of unit.Such as, these unit can Occur with the intersection of the line at each linear array.

According to fourth aspect, it is provided that the speckle with mask described above reduces device.

According to the 5th aspect, it is provided that include that above-mentioned speckle reduces the laser writer of device, laser printer, laser light Engraving device, microwave radar device or ultrasonic imaging device.

According to the 6th aspect, it is provided that design the method that speckle described above reduces device.

Other benefit includes the dimensional flexibility improved.Can be by mechanically moving or any in electric drive mask Mask produces different speckle pattern.For the real-time change of electric control mask, can be with providing two of similar functions (or more Multiple) one-dimensional phase mask replacement two-dimensional phase mask.Use the method, each unit driven in mask can be substantially reduced The number of the electrode needed.

In one example, laser display system uses DMD (DMD) as display chip, it is possible to use just Array phase mask is handed over to reduce diffusing globe as speckle.The most also other type of display chip can be applied, such as silicon Base fluid brilliant (LCoS), spatial light modulator (SOM) and grating light valve (GLV).

Can be with the electric control of the state of unit in hardware or software or combination enforcement mask.For example, it is possible to The suitable operating environment of such as semiconductor processor performs software.

Although having been described for single aspect, but all features of each aspect can freely be exchanged.

Accompanying drawing explanation

Referring to the drawings, will appreciate that this of the present invention from the following description preferred embodiment provided as non-limiting example A little and other characteristic, in the accompanying drawings:

Fig. 1 shows the photo of speckle pattern；

Fig. 2 shows and includes that speckle reduces mask, the signal of the interior example optical geometry used of laser projector Figure；

Fig. 3 a shows that the speckle of Fig. 2 reduces the schematic diagram of mask；

Fig. 3 b shows that the speckle of Fig. 3 a reduces the mathematical notation of a part for mask；

Fig. 3 c shows that the speckle of first time period period Fig. 3 a reduces the schematic diagram of a unit of mask；

Fig. 3 d shows that the speckle of second period time period Fig. 3 a reduces the schematic diagram of a unit of mask；

Fig. 3 e shows that the speckle of the 3rd period time period Fig. 3 a reduces the schematic diagram of a unit of mask；

Fig. 3 f shows that the speckle of the 4th period time period Fig. 3 a reduces the schematic diagram of a unit of mask；

Fig. 4 shows that the speckle for generating Fig. 3 a reduces the graphic diagram of Kronecker (Kronecker) algebraically of mask Show；

Fig. 5 shows that the speckle for generating Fig. 2 reduces the flow chart of the method for mask；

Fig. 6 shows that the speckle of Fig. 3 a of two one-dimensional orthogonal array formats reduces the schematic diagram of mask；

Fig. 7 shows that the speckle for controlling Fig. 2 reduces the schematic diagram of mask, reduced form circuit；

Fig. 8 a shows the schematic diagram of flowing of the signal of telecommunication in the circuit of instruction Fig. 7；

Fig. 8 b shows that the figure that state changed with the time of the signal of telecommunication of Fig. 8 a represents；

Fig. 8 c shows the numerical tabular of the speckle image projected to when being controlled on the screen of Fig. 2 by the signal of telecommunication of Fig. 8 b Show；

Fig. 9 a show instruction Fig. 7 circuit in the signal of telecommunication other flowing schematic diagram；

Fig. 9 b shows that the figure that state changed with the time of the signal of telecommunication of Fig. 9 a represents；

Fig. 9 c shows the numerical tabular of the speckle image projected to when being controlled on the screen of Fig. 2 by the signal of telecommunication of Fig. 9 b Show；

Figure 10 shows that the speckle of Fig. 2 of four one-dimensional orthogonal array formats reduces the schematic diagram of mask；

Figure 11 shows and indicates for the showing of the flowing of the signal of telecommunication in the circuit of four the one-dimensional orthogonal arrays controlling Figure 10 It is intended to；

Figure 12 a shows the schematic diagram of the example electricity configuration of the signal of telecommunication of instruction Figure 11；

Figure 12 b shows that the figure that state changed with the time of the signal of telecommunication of Figure 12 a represents；

Figure 13 a shows the schematic diagram of other example electricity configuration of the signal of telecommunication of instruction Figure 11；And

Figure 13 b shows that the figure that state changed with the time of the signal of telecommunication of Figure 13 a represents.

Detailed description of the invention

Fig. 1 shows the specklegram that the radiation coherent source (Tathagata is from the light of laser instrument) being scattered from rough surface generates Case.Dark space corresponds to destructive interference, and speck is corresponding to the interference effect that rises mutually.

Fig. 2 shows the aobvious of the phase place diffusing globe 7 at the intermediate image plane including projecting lens 5,6 (as beam expander) Show system 1.Display system 1 shown in Fig. 2 can include lasing light emitter 2, as photomodulator DMD (DMD) 3, Screen 9 and detector 11.Phase place diffusing globe or speckle reduce mask 7 can be arranged to have parameter N₁、N₂, s and t just Hand over the form of the two-value phase mask of array (OA), wherein, N₁Represent number of times (runs), N₂Represent because of prime number (factors), s table Showing progression (levels), t represents intensity.When extending and irradiate one-wavelength laser at dmd chip 3, can be in phase place diffusion Device or speckle reduce and form full frame monochrome image on mask 7.For each pixel 4 in dmd chip 3, deposit in phase mask 7 At corresponding N_H×N_VSubelement 8, wherein, N_H×N_V=N₂.When laser beam 2 is through phase mask 7, each unit in subelement 8 The phase change of element can be 0 or π radian.DMD pixel 4 can project to the screen 9 with corresponding screen pixels 10 subsequently Above and detected by light intensity detector 11.By mechanically vibration phase mask 7 and keep the other parts of system stable and Static, different speckle pattern can be produced on screen 9 at different time.The time changing speckle pattern cost is configured to short In or equal to the accumulated time of detector (eyes of such as beholder).Such as, during accumulated time, can produce or change N₁Individual speckle pattern.The resolution point (resolution spot) of detector can be pixel 10, and the number of pixel 10 interior element is N₂.Therefore can be by by this N₁Individual speckle pattern is added together by the speckle suppression 1/N of detection in detector 11₂ ^1/2。

At Speckle Phenomena in Optics:Theory and Applications, Joseph W.Goodman, the 6th chapter, page 222, in formula (6-66), discuss the design of the phase mask with some orthogonal property. Specifically, this book consider a set of M diffuser structures irradiation condition so that:

$\underset{m=1}{\overset{M}{\mathrm{\Σ}}}{P_k}^{\left(m\right)}{P_l}^{{\left(m\right)}^{*}}={\mathrm{\β\δ}}_{k,l},---\left(2\right)$

Wherein, β is positive real constant, δ_klIt it is kronecker delta.

Compared to random diffusing globe, use OA to generate phase mask 7 and decrease the number that required pattern changes.

As an alternative, the machinery of phase mask 7 with the mask without motion phase of electric control, can be avoided to shake by use Dynamic.In other words, the pattern on phase mask can be changed by controlling each unit.But, due to control each element or Unit needs substantial amounts of electrode (reducing the number of unit to be controlled in mask 7 corresponding to speckle), can be difficult to carry out this cloth Put.

In order to overcome this difficulty, two-dimensional phase mask 7 may be implemented as two one-dimensional phase masks 28,29, in Fig. 7 Shown in.These can be referred to as the Kronecker algebraically of orthogonal array (OA).One-dimensional phase mask 28,29 can with superposition, connect Touch or separate, but can be disposed such that laser beam passes two masks 28,29.One-dimensional phase mask 28,29 can be by Be formed as using parallel line or belt as through their column or row.The parallel lines of the first mask can be with the parallel lines of the second mask Vertically.It is not required to single electrode to each unit controlling in two-dimensional mask, but in only two one-dimensional phase masks 28,29 Each line need electrode.Therefore, it can reduce the number of electrode.

As the special case of orthogonal array, can be formed by Sylvester by using two one-dimensional plates (Sylvester) the Ha Dema matrix that method builds.Additionally, by the one-dimensional phase mask using more than two, one can be entered Step reduces the number of required electrode.

The application of the phase mask obtained from OA and structure

The mechanical vibration of one two-dimensional phase mask

When being designed for the orthogonal diffusing globe of two-value that speckle reduces, the orthogonal property of OA is particularly useful, i.e. for N₁× N₂OA:A has two levels (-1 and 1 or π and 0 phase change), and all row are the most orthogonal, then can obtain following relation

A^TA=β δ_{K, l}, (3)

Wherein, β is positive real constant, δ_klIt it is kronecker delta.This characteristic will make to project after two-value diffusing globe Speckle pattern meet following relation

$\underset{m=1}{\overset{M}{\mathrm{\Σ}}}{P_k}^{\left(m\right)}{P_l}^{{\left(m\right)}^{*}}={\mathrm{\β\δ}}_{k,l},---\left(4\right)$

Wherein, P_k ^(m)And P_l ^(m)Represent that m-th diffusing globe passes through kth and the l projection lenses resolution element during realizing Element (resolution element) projects to the field on screen.

Utilize this specific diffusing globe (N₁×N₂OA), changed by the N step of phase place diffusing globe during accumulated time, speckle CR 1/N can be reduced to₂ ^1/2.Additionally, utilize this to configure, because the Ha Dema matrix of the OA multiple that should be 1,2 or 4 than rank is cleverer Live, so there is motility further below: make the size of mask mate into an eye (or detector) and differentiate in point The desirable number of element differentiated by projecting lens.

Fig. 3 a shows an example of the phase mask 7 obtained with the form of OA.It with there are 1920 × 1080 The DMD display chip 3 of pixel is compatible.For simplifying diagram, use OA (4,3,2,2) (Fig. 3 b) as the origin of phase mask 7, vacation Determining the rectangle that projector pixel 4 is width/height=1/3, wherein, 1 (in vain) and-1 (black) represent that 0 and π radian phase changes respectively Become.The pattern 8 of mask 7 is formed, as shown in figure 3b by the row of OA (4,3,2,2).Pattern 8 is when the accumulation of detector 11 For each resolution point (or pixel) 10 during between, as shown in Fig. 3 c-f.In other words, by four (1x3) phase masks A phase mask in 8.1-8.4 irradiates each pixel 4.

When the pattern 8.1 shown in use Fig. 3 c is as the phase mask of pixel 4, the light intensity of detector 11 sensing is

I₁=| A₁+A₂+A₃|²

=| A₁|²+|A₂|²+|A₃|²+2A₁A₂+2A₁A₃+2A₂A₃. (5)

Wherein, A_iIt is to differentiate, by the i-th of projecting lens 6, the random mottle field that element projects on detector 11.With To represent 2A_iA_jMore exact way be A_i ^*A_j+A_iA_j ^*, wherein, A_i ^*It is A_iConjugation.

When using the pattern 8.2 shown in Fig. 3 d as phase mask, the light intensity of detector 11 sensing is

I₂=| A₁-A₂-A₃|²

=| A₁|²+|A₂|²+|A₃|²-2A₁A₂-2A₁A₃+2A₂A₃. (6)

When using the pattern 8.3 shown in Fig. 3 e as phase mask, the light intensity of detector 11 sensing is

I₃=|-A₁+A₂-A₃|²

=| A₁|²+|A₂|²+|A₃|²-2A₁A₂+2A₁A₃-2A₂A₃. (7)

When using the pattern 8.4 shown in Fig. 3 f as phase mask, the light intensity of detector 11 sensing is

I₄=|-A₁-A₂+A₃|²

=| A₁|²+|A₂|²+|A₃|²+2A₁A₂-2A₁A₃-2A₂A₃. (8)

Total light intensity is the sum of the above intensity calculated

I=I₁+I₂+I₃+I₄

=4 (| A₁|²+|A₂|²+|A₃|²). (9)

As indicated in formula (9), the cross term in formula (5) to formula (8) disappears.Therefore, by phase mask 8 (8.1-8.4) four steps change, it is possible to obtain three independent speckle image.

Generally, we can assume that use N₂N₄×N₁N₃OA C is as the origin of phase mask 7.In this case, light The average of intensity can be

$\stackrel{\‾}{I}=\stackrel{\‾}{N_2{N}_4\underset{k=1}{\overset{N_1{N}_3}{\mathrm{\Σ}}}{\left|A_k\right|}^2}=N_1{N}_2{N}_3{N}_4{J}_A.---\left(10\right)$

This supposes: owing to the characteristic of screen 9 is the most constant, thus all | A_k|²There is identical intensity J_A.In order to obtain speckle CR, we also need to know the standard deviation of light intensity, can be obtained the mark of light intensity by equation below Accurate poor

$\stackrel{\‾}{I^2}=\stackrel{\‾}{{\left(N_2{N}_4\underset{k=1}{\overset{N_1{N}_3}{\mathrm{\Σ}}}{\left|A_k\right|}^2\right)}^2}={N_2}^2{N_4}^2\stackrel{\‾}{\underset{k=1}{\overset{N_1{N}_3}{\mathrm{\Σ}}}{\left|A_k\right|}^4+\underset{k=1,l=1}{\overset{N_1{N}_3}{\mathrm{\Σ}}}{\left|A_k\right|}^2{\left|A_l\right|}^2{|}_{k\≠l}}$

$={N_2}^2{N_4}^2[2N_1{N}_3{J_A}^2+({\left(N_1{N}_3\right)}^2-N_1{N}_3){J_A}^2]={N_2}^2{N_4}^2({N_1}^2{N_3}^2+N_1{N}_3){J_A}^2.---\left(11\right)$

Wherein, the speckle manifested completely is usedNegative exponent statistics characteristic.Therefore, speckle CR is

$\mathrm{CR}=\frac{\sqrt{\stackrel{\‾}{I^2}-{\stackrel{\‾}{I}}^2}}{\stackrel{\‾}{I}}=\frac{\sqrt{{N_2}^2{N_4}^2({N_1}^2{N_3}^2+N_1{N}_3){J_A}^2-{\left(N_1{N}_2{N}_3{N}_4{J}_A\right)}^2}}{N_1{N}_2{N}_3{N}_4{J}_A}=\sqrt{\frac{1}{N_1{N}_3}}.---\left(12\right)$

Therefore, by the N of phase mask 7 during the accumulated time of detector 11₂N₄Individual change, speckle CR can be reduced toIn order to apply this two-dimensional phase mask 7 reduced for speckle, having the mechanical vibration of big phase mask is that have must Want.Substantial amounts of absolute electrode is needed, so the electric control of phase mask 7 is impracticable owing to controlling this phase mask 7.

The electric control of two one-dimensional orthogonal phase masks

In the following example, there are two OA A 13 and B14, as shown in Figure 4.Respectively, they because of prime number be N₁ And N₃, their number of times is N₂And N₄(counting of number of times should be preferably no fewer than because of prime number, i.e. N₂≥N₁And N₄≥N₃)。OA The Kronecker product of A 13 and B 14 is

$C=A\⊗B.---\left(13\right)$

Wherein,Being kronecker delta, the size of C 12 is N₂N₄×N₁N₃.May certify that C 12 is also OA.

$C^{T}C={(A\⊗B)}^T(A\⊗B)=(A^T\⊗B^T)(A\⊗B)=A^{T}A\⊗B^{T}B$

$={\left(N_2{\mathrm{\δ}}_{i,j}\right)|}_{i,j=1\·\·\·N_1}\⊗{\left(N_4{\mathrm{\δ}}_{x,y}\right)|}_{x,y=1\·\·\·N_3}=N_2{N}_4{\mathrm{\δ}}_{k,l}{|}_{k,l=1\·\·\·N_1{N}_3}.---\left(14\right)$

In preferred situation, A13 and B14 may each be orthogonal matrix (OM, such as HM), may certify that C12 is new OM.In It is formula (10) can be write as again:

Fig. 4 has graphically illustrated Kronecker algebraically.A^T15 is the transposition of OA A 13.Make A^TThe q row 16 and B14 of 15 R row 18 be multiplied and will build N₁×N₃Matrix 20.Subsequently it is transformed into 1 × N₁N₃Array is as the o row of Matrix C 12 22, wherein, o=(q-1) N₄+r.Same method can be used to form the pth row 23 of Matrix C 12, and it is from A^TThe s row 17 of 15 Draw with the t row 19 of B14, to form another matrix 21, and p=(s-1) N₄+t。

Show from Fig. 4 and can pass through one-dimensional phase mask M orthogonally_H26 and M_V27 to build two dimension OA phase place Mask M 8.Fig. 5 shows construction step 24, Fig. 6 shows an example, wherein matrix A 13, B14 be OA (4,3,2, 2)9.The phase pattern 25 using each row of Kronecker product C 12 to be formed from generating from Matrix C 12 in order draws Phase pattern M8.

In another example, Fig. 7 shows to use two one-dimensional orthogonal phase-plates 28,29 to form phase mask 7 Transmission optics geometry.First phase mask 28 includes that One-Dimensional Water flat rubber belting or line, second phase mask 29 include one-dimensional hanging down Straight band or line.For convenience with clear, it is described and illustrated vertically and horizontally line, but other orientation is feasible.From OA B 12 draw the unit 26 in first phase mask 28, and they control bus 30 by the first son and are connected to the first control bus 32. In first phase mask 28, there is band or the line of 1080 × 3 electric control, and it is by having the first of M1 output port Encoder AD1 34 controls.Draw the unit 27 second phase mask 29 from OA A 11, they control total by the second son Line 31 is connected to the second control bus 33.The band of 1920 × 3 electric control is there is in this example in second phase mask 29, And it is controlled by the second encoder AD235 with M2 output port.

Fig. 8 a shows example electric control method 36.Respectively, sub-control bus 30,31 is by corresponding three circuits It is connected to control bus 32,33, and is subsequently attached to the corresponding output port of encoder AD134 and AD235.

Fig. 8 b showing, output that draw from OA B 14 and OA A 13, from encoder AD1 34 and AD2 35 is believed The state of numbers 37.Because the size from the product OA C 12 of OA A 13 and OA B 14 is 16 × 9, it is possible in detection In the accumulated time of device 11,16 different speckle pattern are projected in the respective pixel 10 of screen 9.Fig. 8 c shows Time t₀To t₁38、t₁To t₂ 39、...、t₁₄To t₁₅ 40、t₁₅To t₁₆The speckle distribution of 41.In Fig. 8 c, k (k is 1,2, 3...16) combination by the first module 26 in first phase mask 28 and the second unit 27 in second phase mask 29 is caused The speckle pattern of modulation.It draws from the row k of phase pattern 23 and in the respective pixel 10 that is projected to screen 9.

Fig. 9 a shows another electric control method 42.Fig. 9 b shows from encoder AD1 34 and encoder AD2 The state of the output signal 43 of 35.Speckle pattern is identical for all pixels of screen 9 within the same time period.Example As, at time t₀To t₁ 44、t₁To t₂ 45、...、t₁₄To t₁₅ 46、t₁₅To t₁₆Each speckle in the speckle distribution of 47 divides Cloth is identical, as shown in Fig. 9 c.

Compared to HM, the two-value diffusing globe generated from OA is more flexible.Projecting lens in eyes differentiate point is differentiated When the number of element is not equal to the rank of HM, introduce the HM that more increases of rank so that the size of the diffusing globe unit needed even more Little.Especially for laser-projector, because the small pixel size of modulation device (e.g., grating light valve (GLV)), so this needs In order to form the manufacturing technology more accurately of diffusing globe.However, it is possible to use as OA in the case of HM mask is unpractical The mask 7 generated.

For example it is assumed that the number that element differentiated by the projecting lens in an eyes resolution point is 9.Do not exist and can use Rank are the HM of 9.It is that the HM of GLV use (being implicitly present in) higher order of 25 μ m 25 μm is (if rank are 16 to Pixel Dimensions HM), the unit size of the two-value diffusing globe of needs would is that about 6 μ m 6 μm.But, using grid layout is the OA of 16 × 9, As shown in Figure 6, the unit size that needs of two-value diffusing globe 7 would is that about 8 μ m 8 μm, i.e. is more easily manufactured.Additionally, based on The speckle of OA (non-square) mask reduces because prime number reduces because prime number is identical with the speckle of HM mask, i.e. speckle CR is 1/9^1/2 =3, wherein every integration interval 16 step changes.

The electric control of the one-dimensional orthogonal phase mask of more than two

As formula (15) proves, can be by i-th row of the product representation N × NHM of following two one-dimensional array

$A^{\left(i\right)}=\left[\begin{array}{c}{k}_{i,0\×\sqrt{N}}\\ \·\\ \·\\ \·\\ k_{i,j\×\sqrt{N}}\\ \·\\ \·\\ \·\\ k_{i,(\sqrt{N}-1)\×\sqrt{N}}\end{array}\right],$ $B^{\left(i\right)}=\left[\begin{array}{ccccc}{k}_{i,0},& \·\·\·& k_{i,j},& \·\·\·& k_{i,\sqrt{N}-1}\end{array}\right].---\left(16\right)$

Wherein, i=0,1,2...N-1,K is 1 or-1.

If building HM by Sylvester method, then can replace two-dimensional phase with the one-dimensional phase mask of more than two Bit mask.Take HM (16) as example, i-th row of HM can be write as the A with four one-dimensional arraies again⁽ⁱ⁾And B⁽ⁱ⁾Take advantage of Long-pending.

$A^{\left(i\right)}=\left[\begin{array}{c}{k}_{i,0}\\ k_{i,4}\\ k_{i,4}\×k_{i,8}\\ k_{i,8}\end{array}\right]=\left[\begin{array}{c}{k}_{i,0}\\ k_{i,4}\\ k_{i,4}\\ k_{i,0}\end{array}\right]\·\left[\begin{array}{c}{k}_{i,0}\\ k_{i,0}\\ k_{i,8}\\ k_{i,8}\end{array}\right]$

B⁽ⁱ⁾=[k_{I, 0} k_{I, 1} k_{I, 1}×k_{I, 2} k_{I, 2}] (17)

=[k_{I, 0} k_{I, 1} k_{I, 1} k_{I, 0}]·[k_{I, 0} k_{I, 0} k_{I, 2} k_{I, 2}]

Except k_{I, 0}There are four independent variables outside (always 1).Therefore, it can the number of electrode from having two one Eight of dimension phase mask reduce to four with four one-dimensional phase masks.

Figure 10 shows the phase mask that HM (16) generates.High-order HM C is built by two low order HM A 13 and B 14 12.Two-dimensional phase mask M8 is drawn from the phase pattern 23 generated from high-order HM C 12.Phase mask M8 can be divided into and passing through Two one-dimensional phase masks 26,27 that low order HM A and low order HM B designs.Due to the order of two unit in formula (12) Exchange does not affect the orthogonal property of mask 8, it is possible to two one-dimensional phase masks 26 and 27 are modified as simpler form 48、49.According to formula (13), the first one-dimensional mask 48 can be further separated into two one-dimensional masks 48.1,48.2, can be by Second one-dimensional mask 49 is further separated into two one-dimensional masks 49.1,49.2.In other words, can be by making line flatly and vertically Four one-dimensional mask 48.1,48.2,49.1 and 49.2 shapes advanced in ground (as shown in Figure 10, but can use any orientation) Become phase mask 7.These four one-dimensional masks 48.1,48.2,49.1 and 49.2 can in series be placed and to incident radiation Play and effect single, more complicated, that two-dimensional phase mask is identical.Additionally, than if not each unit being needed For the equivalent two-dimensional phase mask of electrical connection, four one-dimensional phase masks 48.1,48.2,49.1 and 49.2 need much less Electrical connection (one, every line).

Figure 11 shows use four one-dimensional orthogonal phase-plates 48.1,48.2,49.1,49.2 to form phase mask The transmission optics geometry of 7.First and second phase masks 50.1,50.2 include One-Dimensional Water flat rubber belting or line, the 3rd He respectively 4th phase mask 51.1,51.2 includes one-dimensional vertical bands or line respectively.According to formula (13), from low order HM A 13 and B 14 Corresponding line draw the unit 48.1,48.2,49.1,49.2 in phase mask 50.1,50.2,51.1,51.2.In this example In, the first and second phase masks 50.1,50.2 exist the band of 1080 × 4 electric control.Phase pattern is by having M1 The encoder AD1 56 of output port controls.There are 1920 × 4 electric control in the third and fourth phase mask 51.1,51.2 Band.Phase pattern is controlled by the encoder AD2 54 with M2 output port.

Figure 12 a shows one of electric control method 58 (4 × 4 elements having in phase mask 8).Figure 12 b illustrates From encoder AD1.1 56.1, encoder AD1.2 56.2, encoder AD2.1 57.1 and encoder AD2.2 57.2 The state of output signal 59.Identical with shown in Fig. 8 c in the speckle pattern of different time.

Figure 13 a shows another electric control method 60.Figure 13 b shows from encoder AD1.1 56.1, encoder The state of the output signal 61 of AD1.2 56.2, encoder AD2.1 57.1 and encoder AD2.2 57.2.At different time Speckle pattern identical with Fig. 9 c.

When using high-order HM, the advantage replacing a two-dimensional phase mask with several one-dimensional phase masks becomes apparent from.Example As, when using HM (256), two-dimensional phase mask need 256 control electrodes (that is, every unit one). The number using two one-dimensional phase masks to be needed by electrode reduces to 32 (that is, each 16 line), and is using Four, six, eight one-dimensional phase masks time be further reduced to 22,18,16 respectively.Choose HM phase mask Particular build method depends on the system requirements specifically applied.

Use Kronecker algebraically as above, it is possible to use two OA structure higher OA in rank that rank are lower, permissible Two dimension diffusing globe is replaced with two one-dimensional diffusing globes.It is substantially reduced the number of each unit (line or belt) needing control, Ke Yigeng Easily banding pattern unit is connected to drive electrode.This makes electric control simpler without motion two-value phase place diffusing globe.Application bag Include the full frame projector using DMD (DMD).Electric control diffusing globe can be substantially reduced actuator in this way Driving frequency and power (because the yardstick of diffusing globe is bigger).

As technical staff will be appreciated that, can be in the situation without departing from the scope of the invention the most defined in the appended claims The details of lower change above example.

It is, for example possible to use different types of electricity or other control.The electricity that can use pattern changes and Mechanical Moving Combination.

Technical staff will more easily understand many combinations, amendment or the modification of above example feature, and these Combination, amendment or modification are intended to be formed the part of the present invention.

Claims (25)

1. speckle reduces a device, including:

Radiation path；And

The speckle that is arranged in described radiation path reduces mask, described mask include being configured to being formed on described mask with The cell array of the pattern of time change,

Wherein said speckle reduces mask by first phase mask arranged in series in described radiation path and second phase Mask is formed, and wherein said first phase mask includes M₁Individual electrically controllable parallel lines, described second phase mask include by It is arranged to become the M of non-zero angle with the parallel lines of described first phase mask₂Individual electrically controllable parallel lines；And

Controller, is configured to first signal of telecommunication or second signal of telecommunication are applied to described first phase mask and described respectively Each parallel lines of two phase mask, incide each parallel lines to selectively change between first phase and second phase The phase place of radiation；

Wherein, described controller is configured to the N according to the progression factor 2₁×M₁Orthogonal array A and the N of the progression factor 2₂×M₂Just Handing over array B to apply the first output signal or the second output signal, described controller is configured to:

M to described first phase mask₁Each parallel lines application in individual parallel lines is corresponding to the M of orthogonal array A₁In row The voltage of each row, wherein according to the N of orthogonal array A₁Each row order in row changes putting down at described first phase mask The voltage of application at line；And

Order every time for the voltage of application at the parallel lines of described first phase mask changes, and covers described second phase The M of mould₂Each parallel lines application in individual parallel lines is corresponding to the M of orthogonal array B₂The voltage of each row in row, wherein basis The N of orthogonal array B₂Each row order in row changes the voltage of application at the parallel lines of described second phase mask.

2. speckle as claimed in claim 1 reduces device, and wherein, described pattern is in phase pattern and intensity pattern Individual.

3. the speckle as described in claim 1 or claim 2 reduces device, and wherein, described mask is arranged to about described Radiation path is fixed.

4. speckle as claimed in claim 1 reduces device, and wherein, described cell array includes that number is different from column number OK.

5. speckle as claimed in claim 1 reduces device, also includes: can be in controller and described first phase mask and institute State the electrode connected between each parallel lines of second phase mask.

6. speckle as claimed in claim 5 reduces device, also includes: the control connecting said electrodes to described controller is total Line.

7. speckle as claimed in claim 1 reduces device, wherein, at the parallel lines and described second of described first phase mask Intersection between the parallel lines of phase mask forms electrically controllable unit.

8. speckle as claimed in claim 1 reduces device, and wherein, described second parallel lines are arranged to substantially with described the One parallel lines are vertical.

9. speckle as claimed in claim 1 reduces device, wherein, described second phase mask and described first phase mask phase Contact and be superimposed upon on described first phase mask.

10. speckle as claimed in claim 1 reduces device, also includes: each line of described first parallel lines is connected to institute State the first control bus of controller and each line of described second parallel lines is connected to the second control of described controller Bus.

11. speckles as according to any one of claim 7-10 reduce devices, wherein, through each unit of described mask It is 0 or π radian that the gross phase of radiation changes.

12. speckles as claimed in claim 1 reduce device, and wherein, described mask is transmission mask or reflection mask.

13. speckles as claimed in claim 1 reduce device, and wherein, described speckle reduces the unit of mask and has two states.

14. speckles as claimed in claim 1 reduce device, wherein, the described pattern bag on time dependent described mask Include Ha Dema matrix or orthogonal array.

15. speckles as claimed in claim 1 reduce devices, and wherein, described speckle reduces mask by selected from the material shape of lower group Becoming, described group is made up of pottery, para-electric, quartz and glass.

16. speckles as claimed in claim 1 reduce device, also include: be arranged in the beam expander in described radiation path.

17. speckles as claimed in claim 1 reduce device, and wherein, described mask is located substantially in described radiation path At intermediate image plane.

18. as claim 1,2, speckle according to any one of 4-10 and 12-17 reduce device, wherein, described first phase The parallel lines of mask are arranged to change the phase place of incident radiation, the parallel lines of described second phase mask be arranged to change into Penetrate the phase place of radiation and also be arranged such that at the parallel lines of described first phase mask and described second phase mask The intersection of parallel lines forms unit.

19. speckles as claimed in claim 3 reduce device, and wherein, the parallel lines of described first phase mask are arranged to change Becoming the phase place of incident radiation, the parallel lines of described second phase mask are arranged to change the phase place of incident radiation and also by cloth It is set to so that forming unit in the intersection of the parallel lines of the parallel lines of described first phase mask and described second phase mask.

20. speckles as claimed in claim 11 reduce device, and wherein, the parallel lines of described first phase mask are arranged to change Becoming the phase place of incident radiation, the parallel lines of described second phase mask are arranged to change the phase place of incident radiation and also by cloth It is set to so that forming unit in the intersection of the parallel lines of the parallel lines of described first phase mask and described second phase mask.

21. 1 kinds of laser writers, reduce device including the speckle as according to any one of claim 1-20.

22. 1 kinds of laser printers, reduce device including the speckle as according to any one of claim 1-20.

23. 1 kinds of laser lithography devices, reduce device including the speckle as according to any one of claim 1-20.

24. 1 kinds of microwave radar devices, reduce device including the speckle as according to any one of claim 1-20.

25. 1 kinds of ultrasonic imaging devices, reduce device including the speckle as according to any one of claim 1-20.