CN109001904A - A kind of bearing calibration based on dynamic LUT liquid crystal wavefront corrector - Google Patents
A kind of bearing calibration based on dynamic LUT liquid crystal wavefront corrector Download PDFInfo
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- G—PHYSICS
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- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/0025—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 for optical correction, e.g. distorsion, aberration
- G02B27/0068—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 for optical correction, e.g. distorsion, aberration having means for controlling the degree of correction, e.g. using phase modulators, movable elements
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
- G09G3/36—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source using liquid crystals
- G09G3/3607—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source using liquid crystals for displaying colours or for displaying grey scales with a specific pixel layout, e.g. using sub-pixels
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Abstract
The invention discloses a kind of bearing calibrations based on dynamic LUT liquid crystal wavefront corrector, belong to liquid crystal wavefront correction field.The method of the present invention is by building optical path, building LUT data model, which provides, a kind of can overcome that temperature fluctuation is influencing, high-precision LUT calculation method, Phase Modulation Properties at each temperature are measured, LUT data model is established using least square fitting, after variation of ambient temperature, the temperature to be worked by current spatial optical modulator substitutes into LUT data model, obtains reasonable LUT data.Achieve the effect that carry out wavefront correction to incident light, overcoming environment temperature and rising and falling leads to the influence of liquid crystal wavefront corrector phase-modulation precision reduction.
Description
Technical field
The present invention relates to a kind of bearing calibrations based on dynamic LUT liquid crystal wavefront corrector, belong to liquid crystal wavefront correction neck
Domain.
Background technique
Commercial LCD space light modulator is with liquid crystal on silicon (the Liquid crystal based on reflective electrical addressing
On silicon, LCOS) based on, also there is the LCOS of a small amount of light addressing, there are also the liquid crystal devices of about 100 or so pixels of transmission-type
Part；LCD space light modulator (liquid crystal spatial light modulator) basis of reflective electrical addressing
The orientation of its internal liquid crystal is different, can be divided into two kinds: 1) LCD space light modulator of amplitude type, this liquid crystal spatial light tune
Device processed is basically used for modulation light intensity, for example, the purposes of display aspect.2) LCD space light modulator of phase-type, wherein with liquid
The orientation of the upper layer and lower layer oriented layer of crystal layer contact is parallel to each other, and liquid crystal is all flat from upper layer to next time in differently- oriented directivity wherein
Capable, this LCD space light modulator is chiefly used in optical system, for example, for being used as wavefront school in adaptive optics system
Positive device, therefore, also referred to as liquid crystal wavefront corrector here, working principle, characteristic and apply document [Zhang Z, You Z,
Chu D.Fundamentals of phase-only liquid crystal on silicon(LCOS)devices[J]
.Light Science&Applications, 2014,3 (10): e213] on be described.
Liquid crystal wavefront corrector can be used for ground large-aperture optical telescope to astronomical target carry out it is high-resolution at
As observation.The target observed is usually fixed star, generally weaker than darker.When the light of fixed star is reached on earth atmosphere, it can recognize
To be plane wave；But earth surface has the atmosphere of 10 to 20 kilometers of thickness, on the one hand, temperature caused by being irradiated due to sunlight is risen
Volt is so that air index is uneven, and on the other hand, atmosphere itself has absorption, and therefore, atmosphere is further to object brightness to meeting
Weaken, while atmosphere also reduces target imaging resolution ratio to the dynamic disturbances phenomenon before light wave, seriously affects image quality.Cause
This, people overcome the disturbance of atmospheric turbulance using adaptive optics system, and adaptive optics wavefront correction system has been rice
Grade or more bore optical telescope necessary equipment.Adaptively correcting system before light wave in atmosphere adaptive optical technique field
System, function is to carry out real-time compensation correction to the target light distorted wavefront of continuous incident telescope, ideal real-time to obtain
Optical imagery, working principle is in [Francois Roddier, Adaptive optics in astronomy, Cambridge
University Press, 1999, Part two] on be described in detail.Wave-front corrector pair is generally utilized in adaptive optics system
Distorted wavefront compensates, and wherein wave-front corrector includes distorting lens, liquid crystal wavefront corrector etc..And with distorting lens ratio, liquid crystal
Wave-front corrector has the advantage of high pixel density.
Using liquid crystal wavefront corrector required light beam can also be obtained to incident laser beam shaping.At present with
Laser technology using more and more extensive, for example, laser weapon, laser radar, laser communication, laser automobile lamp, laser
The fields such as processing, laser fusion, the structure light in micro-imaging and laser display, these applications require high quality
Laser beam, energy need to be distributed as required, but Gaussian Profile is presented in the light intensity of the laser beam of common lasers outgoing, this
Limit its application range.Therefore, people have conducted extensive research, and one of used technological means is exactly empty using liquid crystal
Between optical modulator shaping is carried out to incident laser beam, obtain satisfactory output beam.With the structure light in micro-imaging
For, LCD space light modulator and polarizing film are introduced in illumination path, it is suitable to apply on LCD space light modulator
Pattern generates the striped at light and shade (or black and white) interval, projects on sample by object lens, will be by the focussing plane of sample
The Structured Illumination of candy strip, compared with traditional illumination, the resolution ratio of imaging is can be improved in Structured Illumination.
In above-mentioned application, the driving process of liquid crystal wavefront corrector is as follows: firstly, generating M × N picture by computer
The gray scale picture G1 of element, wherein M and N is the pixel number of LCD space light modulator in the x and y direction respectively；Secondly, by grey
Spend picture and LCD space light modulator be sent to by drive software, at this point, on grayscale image G1 each pixel gray scale G1i,j(0
≤ i≤M, 0≤j≤N) corresponding gray scale G2 found by LUT (look-up table, look-up table)i,j(0≤i≤M, 0≤j
≤ N), to obtain grayscale image G2；Finally, passing through the analog-to-digital conversion of driving circuit intralamellar part, grayscale image G2 is converted into accordingly
Voltage, be applied in each pixel of liquid crystal wavefront corrector, to regulate and control to incident light.It can from the above process
It arrives, LUT is the key factor for influencing the Phase Modulation Properties of liquid crystal wavefront corrector.And LUT is by measuring at a certain temperature
The Phase Modulation Properties of liquid crystal wavefront corrector obtain, obtained LUT is also suitable only for working at this temperature, work as temperature
When variation, which will lead to phase modulation errors.The Phase Modulation Properties measurement method of liquid crystal wavefront corrector [is opened in document
Asia is super, Hu Lifa, Peng Zenghui, wait liquid crystal wavefront corrector overdrive matrix method of measuring [J] liquid crystal and display,
2014,29 (5), 709-715.] on be discussed in detail.
It is more sensitive to temperature due to liquid crystal that LUT, which is affected by temperature: temperature it is too low it at solid-state, temperature it is excessively high it at
Isotropic liquid, liquid crystal phase can be only present in certain temperature range；And when being in liquid crystalline phase, electro-optical characteristic
Closely related with environment temperature, in document, [Hu Lifa, Peng Zenghui, Wang Qidong wait the response of the pure position phase liquid crystal modulator of special for this
Property calculate [J] liquid crystal and display, 2017,32 (3): 182-189] in have a detailed description.In adaptive optics application, one day
When even Various Seasonal is tested, unavoidably there is the fluctuating of environment temperature in interior different time sections；If carried out in outfield
Experiment, temperature fluctuation can more acutely.Therefore, the adaptive optics system for being mounted with liquid crystal wavefront corrector is placed in by people
In the room library DS (Coude), can suitably reduce the fluctuation of temperature, but still there are the fluctuatings of near room temperature a small range can
Energy.However influence of the liquid crystal material to temperature is more sensitive, the fluctuating of temperature will lead to its response speed, phase modulation depth,
Especially LUT (Look-up table, look-up table) changes, to influence the phase-modulation precision of liquid crystal wavefront corrector
Equal electro-optical characteristics, and these characteristics are very crucial for the application of liquid crystal wavefront corrector.On the other hand, commercial liquid crystal wavefront
The typically no temperature regulating device of corrector, and the liquid crystal wavefront corrector of Meadowlark company also only has heating apparatus, prevents temperature
It spends low；Meanwhile the LUT of business liquid crystal wavefront corrector is set under a certain room temperature and wavelength when leaving the factory, one when experiment
As do not change.It can be seen that general liquid crystal wavefront corrector does not have the ability for overcoming temperature fluctuation, in application process
Temperature change will lead to its phase-modulation precision and can reduce, and influence its practical application effect.Therefore, overcome caused by temperature fluctuation
The major issue that phase-modulation accuracy decline and liquid crystal wavefront corrector need to solve in the application.
Summary of the invention
To solve the above-mentioned problems, overcome influence of the temperature to LCD space light modulator phase-modulation precision, the present invention
A kind of bearing calibration based on dynamic LUT liquid crystal wavefront corrector is provided.By building optical path, building LUT data model is provided
It is a kind of to overcome that temperature fluctuation is influencing, high-precision LUT calculation method, the Phase Modulation Properties at each temperature are surveyed
Amount, establishes LUT data model using least square fitting, after variation of ambient temperature, is worked by current spatial optical modulator
Temperature, substitute into LUT data model, obtain reasonable LUT data.
Technical solution of the present invention:
By constructing a LUT data model, after variation of ambient temperature, by building one optical path, building LUT data
Model, after variation of ambient temperature, the temperature to be worked by current liquid crystal wave-front corrector substitutes into LUT data model, obtains conjunction
The LUT data of reason: (1) being T in the operating ambient temperature of liquid crystal wavefront corrector1When, liquid crystal wavefront corrector is measured in wavelength X
Intensity response under different gray scales；(2) light intensity is transformed into phase with the variation of gray level with gray level；(3) will
Obtained phase is transformed into dull curve with the change curve of gray level；(4) it is opened from the corresponding gray level one end of high voltage
Begin, take the corresponding phase of a wavelength, it is divided into N number of gray scale by quantization level N, wherein N is necessarily less than equal to 256, is obtained
Gray scale-grey scale curve, i.e. temperature are T1When, LUT table when wavelength X；(5) when the operating ambient temperature of liquid crystal wavefront corrector becomes
For TNAfterwards, it repeats the above steps, the LUT table at this temperature, under wavelength X can be obtained；(6) by LUT under obtained different temperatures
Data carry out least square fitting, obtain the mathematical model of LUT under different temperatures；
In one embodiment, described to build optical path are as follows: the polarization direction of the polarizer and analyzer is orthogonal, rises
The long axis of the liquid crystal molecule of inclined device and liquid crystal wavefront corrector is orientated 45 degree of angle, according to the principle of polarization optics, light intensity I and phase
The relationship of potential difference δ may be expressed as:Wherein, Imax indicates largest light intensity value, and δ indicates phase difference；ByPhase can be obtained to be represented by with the variation relation of light intensityThe light that laser issues
After the polarizer, transmitted light becomes linearly polarized light, and its polarization direction is consistent with the polarization direction of the polarizer；By being divided rib
After mirror, the part of a part transmission, a part reflection, reflection reaches liquid crystal wavefront corrector；It is reflected by liquid crystal wavefront corrector
Afterwards, Amici prism, a part transmission, a part reflection are reached again；Transmissive portion penetrates analyzer, finally reaches photoelectricity two
The electric signal of pole pipe, photodiode is received by oscillograph, obtains the data of light intensity, and computer carries out liquid crystal wavefront corrector
Control, receives oscilloscope data.
In one embodiment, the operating ambient temperature in liquid crystal wavefront corrector is T1When, it is surveyed in wavelength X
Measure Intensity response of the liquid crystal wavefront corrector under different gray scales are as follows: the linear LUT given when dispatching from the factory is test liquid crystal wavefront
LUT when corrector works；Generate gray level be respectively 0,1,2 ... 256 width gray scale pictures of 255 512 × 512 pixels；So
Afterwards, the grayscale image of 512 × 512 data successively order by gray level from low to high is sent to liquid crystal wavefront correction by computer
Device, the time that each picture is kept are 100ms, and the change of the gray level of the picture of liquid crystal wavefront corrector at any time is driven in test
Change；And the sampling interval 20ms of oscillograph is therefore, each gray level will correspond to 5 data points, collect light intensity and become at any time
The case where change.
In one embodiment, described that light intensity is transformed into phase with the variation of gray level with gray level
Are as follows: it is averaged when same gray level to 5 obtained light intensity datas, improves Intensity response measurement accuracy under the gray scale；To every
After light intensity data in one gray scale is averaged, 256 gray values and corresponding average intensity relationship are obtained.
In one embodiment, described that obtained phase is transformed into dull song with the change curve of gray level
Line are as follows: the light intensity data obtained according to claim 4 is handled, and the smallest light intensity is subtracted, then according to formulaObtain phase distribution.
In one embodiment, LUT data carry out least square fitting under the different temperatures that will be obtained, and obtain
The mathematical model of LUT under different temperatures are as follows: be fitted using formula, the formula are as follows:
Z=Z0+A1*x+A2*x2+A3*x3+A4*x4+A5*x5+B1*y+B2*y2+B3*y3+B4*y4+B5*y5 (Ⅰ)
X is the gray level position in the direction of the x axis of picture, and 0≤x≤255, y are temperature, and 16 DEG C≤y≤26 DEG C；Z is
The position of the gray level of picture in the z-axis direction, and 0≤z≤255；Constant term Z0 and every coefficient A1, A2, A3, A4, A5,
B1, B2, B3, B4, B5 are respectively Z0=8028.22085, A1=-15.4063, A2=0.73756, A3=-0.02041, A4=
2.83892E-4, A5=-1.55766E-6, B1=-1839.40636, B2=172.84044, B3=-8.05492, B4=
0.18623, B5=-0.00171；According to formula, the LUT in 16 DEG C≤y≤26 DEG C at any temperature is calculated, utilizes formula
(I) what is obtained is real number, rounds up to obtain integer；Further, the gray level of driving is more than 255 data, indirect assignment
255；The minus data of the gray level of driving, then indirect assignment 0；Finally obtain the gray-scale data of LUT.
In one embodiment, LUT data carry out least square fitting under the different temperatures that will be obtained, and obtain
The mathematical model of LUT under different temperatures are as follows: be fitted using formula, the formula are as follows:
X is the gray level position in the direction of the x axis of picture, and 0≤x≤255, y are temperature, and 16 DEG C≤y≤26 DEG C；
Z is the gray level position in the z-axis direction of picture, and 0≤z≤255；Constant term z20 and every coefficient A01, A21,
A22, A23, B01, B02, B03, B21, B22 are respectively z20=1255.55138, A01=-11.1413, B01=1.74234,
B02=-0.17339, B03=-0.000549159, A21=0.5787, A22=-0.03319, A23=0.0005792, B21
=0.27354, B22=-0.00357；According to formula (4), any temperature in 16 DEG C≤y≤26 DEG C of temperature range can be calculated
LUT under degree；The real number obtained by formula (II) is rounded up to obtain integer；Further, if there is being more than 255
Data, then indirect assignment 255；And if there is minus data, then indirect assignment 0；Finally obtain the gray-scale data of LUT.
The present invention after constructing LUT data model, variation of ambient temperature, passes through current spatial light modulation by building optical path
The temperature of device work, substitutes into LUT data model, show that having the beneficial effect that for reasonable LUT data overcomes temperature to liquid crystal sky
Between optical modulator phase-modulation precision influence so that the correction accuracy of liquid crystal wavefront corrector is higher.
Detailed description of the invention
Fig. 1 is the light path principle figure that the phase response characteristic of liquid crystal wavefront corrector of the invention detects.Wherein laser 1
The light of sending is after the polarizer 2, and transmitted light becomes linearly polarized light, and its polarization direction is consistent with the polarization direction of the polarizer；
After Amici prism 3, the part of a part transmission, a part reflection, reflection reaches liquid crystal wavefront corrector 4；By liquid crystal wave
After preceding corrector 4 reflects, Amici prism 3, a part transmission, a part reflection are reached again；Transmissive portion penetrates analyzer
5, photodiode 6 is finally reached, the electric signal of photodiode is received by oscillograph 7, obtains the data of light intensity, liquid crystal wavefront
The control of corrector and the reception of oscilloscope data are finally all completed by computer 8.
Fig. 2 is to drive the gray level of the picture of liquid crystal wavefront corrector to change with time in test.
Fig. 3 is that photodiode 6 detects obtained light intensity and changes with time situation.
Fig. 4 is 256 gray values and corresponding average intensity relationship, and wherein light intensity is 5 measured under same gray scale
The average value of a light intensity data.
Fig. 5 is phase distribution with the variation of gray scale, and wherein phase is 0 to the numerical value within the scope of π.
Fig. 6 is phase with gray scale dullness, the curve of consecutive variations.
Fig. 7 is the data of LUT at 16 DEG C.
Corresponding relationship between the gray level of Fig. 8 picture and the gray level of driving
Fig. 9 is the data of the LUT measured in 16 DEG C to 26 DEG C temperature ranges.
The first-order diffraction efficiency of Figure 10 difference LUT at 20 DEG C of room temperature compares.
Specific embodiment
Be described in further details with reference to the accompanying drawing to the specific embodiment of the invention: the present embodiment is with skill of the present invention
Implemented under premised on art scheme, gives detailed embodiment and process, but protection scope of the present invention is not limited to down
The embodiment stated.
Embodiment 1:
A kind of bearing calibration based on dynamic LUT liquid crystal wavefront corrector, including build optical path, building LUT data model,
The verifying of LUT data model calculates LUT data according to the operating temperature of LUT data model and liquid crystal wavefront corrector.
One, optical path is built:
As shown in Figure 1, using the GCI-0601 type direct current voltage reulation optical fiber source of company of Daheng as laser (1)；Using
Two panels new era Science and Technology Co., Ltd.'s diameter is the 5004 type polarizing films of 50mm, as the polarizer (2) analyzer (5)；It adopts
Use Daheng Xinshijiyuan Science & Technology Co., Ltd. GCC-401102 type Amici prism as Amici prism (3)；Using the U.S.
The phase-only modulation type LCD space light modulator of 512 × 512 pixels of Meadowlark company is as liquid crystal wavefront corrector
(4)；(6) are used as using photodiode；(7) are used as using the SDS1102CNL type oscillograph of SIGLENT company；Using industry control
Machine is as computer (8)；
Used GCI-0601 type direct current voltage reulation optical fiber source can be used as white light source, used SDS1102CNL type
Oscillograph sample frequency is 100Mhz.The polarization direction of the polarizer (2) and analyzer (5) is orthogonal, and with liquid crystal wavefront school
The long axis of the liquid crystal molecule of positive device is orientated 45 degree of angle, under these conditions, according to the principle of polarization optics, light intensity I and phase
The relationship of poor δ may be expressed as:Wherein, Imax indicates largest light intensity value.Therefore, byIt can
Phase is obtained to be represented by with the variation relation of light intensityThe light that laser (1) issues passes through the polarizer
(2) after, transmitted light becomes linearly polarized light, and its polarization direction is consistent with the polarization direction of the polarizer；By Amici prism (3)
Afterwards, the part of a part transmission, a part reflection, reflection reaches liquid crystal wavefront corrector (4)；By liquid crystal wavefront corrector (4)
After reflection, Amici prism (3) are reached again, a part transmission, a part reflection；Transmissive portion penetrates analyzer (5), finally
It reaches photodiode (6), the electric signal of photodiode is received by oscillograph (7), obtains the data of light intensity, liquid crystal wavefront school
The positive control of device and the reception of oscilloscope data are finally all completed by computer (8).
Two, LUT data model is constructed:
1. building optical path as shown in Figure 1 according to the above-mentioned method for building optical path, the work of liquid crystal wavefront corrector is set
16 DEG C of environment, the linear LUT given when dispatching from the factory is LUT when testing liquid crystal wavefront corrector work；Generate gray level difference
Be 0,1,2 ... 255 512 × 512 pixels 256 width gray scale pictures；Then, computer (8) is by the gray scale of 512 × 512 data
To scheme the successively order by gray level from low to high, is sent to liquid crystal wavefront corrector, the time that each picture is kept is 100ms,
The gray level of the picture of liquid crystal wavefront corrector is driven to change with time as shown in Figure 2 in test；And between the sampling of oscillograph
Therefore every 20ms, each gray level will corresponding 5 data points, the signal collected as shown in figure 3, Fig. 3 give light intensity with
The case where time change；
2. when same gray level is averaged to 5 obtained light intensity datas in order to reduce noise, light under the gray scale is improved
Strong response measurement precision；After being averaged to the light intensity data in each gray scale, 256 gray values and corresponding average light are obtained
Strong relationship, as shown in Figure 4；
3. handling 2. light intensity data that step obtains, the smallest light intensity is subtracted, then according to formulaPhase distribution is obtained, as shown in figure 5, the phase distribution is 0 to the numerical value within the scope of π；
4. handling 3. data that step obtains, when gray level is respectively 40,68,83,102,126,206, make
For first, second, third and fourth, five, six inflection points, initial data is retained for the data before the first inflection point；In the first inflection point and second
Data between inflection point are overturn down using inflection point as axis；The data of second third inflection point are translated；And so on, will own
Phase with grey scale change curve carry out continuously and dullnessization handle, obtain Fig. 6 phase with gray scale dullness, consecutive variations song
Line；
5. the 5th, by the corresponding 32 quantization levels of a wavelength, the data that previous step is obtained are converted to new gray scale
The relationship that level changes with original gray level, the i.e. data of LUT, as shown in Figure 7.Since there are the gray scales of multiple pictures in Fig. 7
Therefore the gray level of picture is corresponded by level, obtains the LUT data of Fig. 8, Fig. 8 by the gray level of the corresponding driving of grade
Give the corresponding relationship between the gray level of picture and the gray level of driving；
6. the step of to the data at a temperature of other by first to the 5th carries out identical processing, obtain at this temperature
The data of LUT, finally obtain, 16 DEG C, 17 DEG C ... the LUT at 26 DEG C, as shown in Figure 9；
7. the LUT data under the different temperatures 6. obtained to step carry out least square fitting, fitting can be using difference
Method；
A kind of fit approach is to be fitted using following formula:
Z=Z0+A1*x+A2*x2+A3*x3+A4*x4+A5*x5+B1*y+B2*y2+B3*y3+B4*y4+B5*y5 (Ⅰ)
Wherein, 0≤x≤60,16 DEG C≤y≤26 DEG C, 0≤z≤255, and Z0=8028.22085, A1=-15.4063, A2=
0.73756, A3=-0.02041, A4=2.83892E-4, A5=-1.55766E-6, B1=-1839.40636, B2=
172.84044 B3=-8.05492, B4=0.18623, B5=-0.00171.According to formula (I) can be calculated 16 DEG C≤
LUT in y≤26 DEG C at any temperature, what is obtained using public formula (I) is real number, rounds up to obtain integer；Further, it drives
Dynamic gray level is more than 255 data, then indirect assignment 255；The minus data of the gray level of driving, then indirect assignment 0；Most
The gray-scale data of LUT is obtained eventually.
Another fit approach is to be fitted using following formula:
Wherein, z20=1255.55138, A01=-11.1413, B01=1.74234, B02=-0.17339, B03=-
0.000549159, A21=0.5787, A22=-0.03319, A23=0.0005792, B21=0.27354, B2=-
0.00357.According to public formula (II), the LUT in 16 DEG C≤y≤26 DEG C of temperature range at any temperature can be calculated.To by
The real number that formula (II) obtains is rounded up to obtain integer；Further, the gray level of driving has more than 255 data,
Indirect assignment 255；And if the minus data of gray level of driving, indirect assignment 0；Finally obtain the number of greyscale levels of LUT
According to.
Three, LUT data model is verified
At a certain temperature, when loading identical balzed grating, pattern, compare liquid crystal wavefront corrector work in different LUT
The difference for the diffraction efficiency that lower image camera detects, more reasonable LUT, corresponding first-order diffraction efficiency are higher；According to public affairs
Formula (I) or formula (II) can obtain include 20 degrees Celsius and other at a temperature of LUT data,.Test optical path it is different from Fig. 1 it
Be in, substitute photodiode 6 with CCD camera, in addition only with a polarizing film 2, and adjust its polarization direction to
Long axis of liquid crystal molecule direction is identical in LCOS.The grayscale image for applying 30 wavelength on liquid crystal wavefront corrector, in CCD camera
The diffraction luminous point of zero level and level-one is obtained, selects reasonable region respectively on camera, sums, respectively obtains after removing back end noise
The light intensity of level-one is set to diffraction efficiency divided by the summation of zero level and level-one light intensity by the light intensity of level-one and zero level.Experiment is in room
It is carried out at 20 DEG C of temperature, the diffraction image that camera obtains when by loading 16 DEG C, 18 DEG C, 20 DEG C, 24 DEG C of LUT respectively calculates
Their diffraction efficiency out, and diffraction efficiency data are fitted, as shown in Figure 10.As seen from Figure 10, what different LUT was obtained spreads out
It is not identical to penetrate efficiency, LUT only corresponding with 20 degree of room temperature just has highest diffraction efficiency 61.1%；And in 16 DEG C of correspondences
LUT under when working, diffraction efficiency is reduced to 54.8%.The fluctuation of environment temperature can phase tune to liquid crystal wavefront corrector
System can have a certain impact, and reflection results in diffraction efficiency to reduce into this experiment, therefore, be loaded according to actual temperature corresponding
LUT, rather than using traditional fixation LUT tested when, can be improved the phase-modulation precision of liquid crystal wavefront corrector.
Four, LUT data are calculated according to LUT data model
In liquid crystal wavefront corrector work, according to the temperature of working environment, being generated using above-mentioned formula (I) or (II) should
At a temperature of LUT data, using the LUT can make liquid crystal wavefront corrector work in the highest state of phase-modulation precision.
Although the present invention has been described by way of example and in terms of the preferred embodiments, it is not intended to limit the invention, any to be familiar with this skill
The people of art can do various change and modification, therefore protection model of the invention without departing from the spirit and scope of the present invention
Enclosing subject to the definition of the claims.
Claims (7)
1. a kind of bearing calibration based on dynamic LUT liquid crystal wavefront corrector, which is characterized in that the method is by building
Optical path, one LUT data model of building, the verifying of LUT data model, after variation of ambient temperature, pass through current liquid crystal wavefront school
The temperature of positive device work, substitutes into LUT data model, obtains reasonable LUT data；The construction step of the LUT data model
Are as follows:
It (I) is T in the operating ambient temperature of liquid crystal wavefront corrector1When, in wavelength X measurement liquid crystal wavefront corrector in different ashes
Intensity response under degree；
(II) light intensity is transformed into phase with the variation of gray level with gray level；
(III) obtained phase is transformed into dull curve with the change curve of gray level；
(IV) since the corresponding gray level one end of high voltage, the corresponding phase of a wavelength is taken, it is divided by quantization level N
N number of gray scale, wherein N is necessarily less than equal to 256, obtains gray scale-grey scale curve, i.e. temperature is T1When, LUT table when wavelength X；
(V) when the operating ambient temperature of liquid crystal wavefront corrector becomes TNAfterwards, repeat the above steps, can obtain at this temperature,
LUT table under wavelength X；
(VI) LUT data under obtained different temperatures are subjected to least square fitting, obtain the mathematical modulo of LUT under different temperatures
Type.
2. a kind of bearing calibration based on dynamic LUT liquid crystal wavefront corrector according to claim 1, which is characterized in that
Described builds optical path are as follows: the polarization direction of the polarizer (2) and analyzer (5) is orthogonal, the polarizer (2) and liquid crystal wavefront school
The long axis of the liquid crystal molecule of positive device is orientated 45 degree of angle, and according to the principle of polarization optics, the relationship of light intensity I and phase difference δ can tables
It is shown as:Wherein, ImaxIndicate largest light intensity value；ByPhase can be obtained with the change of light intensity
Change relationship is represented byFor the light that laser (1) issues after the polarizer (2), it is inclined that transmitted light becomes line
Shake light, and its polarization direction is consistent with the polarization direction of the polarizer；After Amici prism (3), a part transmission, a part is instead
It penetrates, the part of reflection reaches liquid crystal wavefront corrector (4)；After liquid crystal wavefront corrector (4) reflection, light splitting rib is reached again
Mirror (3), a part transmission, a part reflection；Transmissive portion penetrates analyzer (5), finally reaches photodiode (6), photoelectricity
The electric signal of diode is received by oscillograph (7), obtains the data of light intensity, computer (8) controls liquid crystal wavefront corrector
System, receives oscilloscope data.
3. a kind of bearing calibration based on dynamic LUT liquid crystal wavefront corrector according to claim 1, which is characterized in that
The operating ambient temperature in liquid crystal wavefront corrector is T1When, in wavelength X measurement liquid crystal wavefront corrector in different ashes
Intensity response under degree are as follows: the linear LUT given when dispatching from the factory is LUT when testing liquid crystal wavefront corrector work；Generate ash
Spend grade be respectively 0,1,2 ... 256 width gray scale pictures of 255 512 × 512 pixels；Then, computer (8) is counted 512 × 512
According to the grayscale image successively order by gray level from low to high, be sent to liquid crystal wavefront corrector, the time that each picture is kept
It is 100ms, drives the gray level of the picture of liquid crystal wavefront corrector to change with time in test；And the sampling interval of oscillograph
Therefore, each gray level will correspond to 5 data points to 20ms, collect the case where light intensity changes over time.
4. a kind of bearing calibration based on dynamic LUT liquid crystal wavefront corrector according to claim 1, which is characterized in that
Described is transformed into phase with the variation of gray level with gray level for light intensity are as follows: to 5 obtained when same gray level
Light intensity data is averaged, and Intensity response measurement accuracy under the gray scale is improved；Light intensity data in each gray scale is averaged
Afterwards, 256 gray values and corresponding average intensity relationship are obtained.
5. according to claim 1 or a kind of bearing calibration based on dynamic LUT liquid crystal wavefront corrector as claimed in claim 4,
It is characterized in that, described be transformed into dull curve with the change curve of gray level for obtained phase are as follows: according to right
It is required that the light intensity data obtained described in 4 is handled, the smallest light intensity is subtracted, then according to formula?
To phase distribution.
6. a kind of bearing calibration based on dynamic LUT liquid crystal wavefront corrector according to claim 1, which is characterized in that
LUT data carry out least square fitting under the different temperatures that will be obtained, and obtain the mathematical model of LUT under different temperatures
Are as follows: it is fitted using formula, the formula are as follows:
Z=Z0+A1*x+A2*x2+A3*x3+A4*x4+A5*x5+B1*y+B2*y2+B3*y3+B4*y4+B5*y5 (Ⅰ)
Wherein, x is the gray level position in the direction of the x axis of picture, and 0≤x≤255, y are temperature, and 16 DEG C≤y≤26
℃；Z is the gray level position in the z-axis direction of picture, and 0≤z≤255, and Z0=8028.22085, A1=-
15.4063, A2=0.73756, A3=-0.02041, A4=2.83892E-4, A5=-1.55766E-6, B1=-
1839.40636 B2=172.84044, B3=-8.05492, B4=0.18623, B5=-0.00171；According to formula, calculate
The LUT in 16 DEG C≤y≤26 DEG C at any temperature is obtained, what is obtained using formula (I) is real number, it rounds up to obtain integer,
Further, the gray level of driving is more than 255 data, indirect assignment 255；The minus data of the gray level of driving, then directly
Connect assignment 0；Finally obtain the gray-scale data of LUT.
7. a kind of bearing calibration based on dynamic LUT liquid crystal wavefront corrector according to claim 1, which is characterized in that
LUT data carry out least square fitting under the different temperatures that will be obtained, and obtain the mathematical model of LUT under different temperatures
Are as follows: it is fitted using formula, the formula are as follows:
Wherein, x is the gray level position in the direction of the x axis of picture, and 0≤x≤255, y are temperature, and 16 DEG C≤y≤26
℃；Z is the gray level position in the z-axis direction of picture, and 0≤z≤255, z20=1255.55138, A01=-
11.1413, B01=1.74234, B02=-0.17339, B03=-0.000549159, A21=0.5787, A22=-
0.03319, A23=0.0005792, B21=0.27354, B2=-0.00357；According to formula (4), temperature can be calculated
LUT in 16 DEG C≤y≤26 DEG C in section at any temperature；The real number obtained by formula (II) is rounded up to obtain whole
Number, further, the gray level of driving is more than 255 data, indirect assignment 255；The minus data of the gray level of driving, directly
Assignment 0 is connect, the gray-scale data of LUT is finally obtained.
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109739033A (en) * | 2019-02-25 | 2019-05-10 | 中国科学院光电技术研究所 | A kind of liquid-crystal aberration correcting method of no Wavefront detecting |
| CN111489686A (en) * | 2020-03-31 | 2020-08-04 | 深圳市奥拓电子股份有限公司 | Display screen thermal effect compensation adjustment display device, method and system |
| CN112116887A (en) * | 2020-11-23 | 2020-12-22 | 南京芯视元电子有限公司 | Display chip flatness correction system of LCoS spatial light modulator |
| CN113242416A (en) * | 2021-04-23 | 2021-08-10 | 苏州天准科技股份有限公司 | Method for correcting gray scale nonlinearity of digital projector, storage medium and projection system |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102109414A (en) * | 2010-12-15 | 2011-06-29 | 深圳大学 | Method and device for calibrating phase modulation of spatial light modulators by utilizing heterodyne interference |
| CN102540531A (en) * | 2012-01-11 | 2012-07-04 | 中国科学院长春光学精密机械与物理研究所 | Transitional grey level driving method for increasing response speed of liquid crystal wave-front corrector |
| CN102566114A (en) * | 2012-01-11 | 2012-07-11 | 中国科学院长春光学精密机械与物理研究所 | GPU (graphic processing unit)-assisted transition grayscale driving method of liquid crystal wave-front corrector |
| CN203365108U (en) * | 2013-07-08 | 2013-12-25 | 内蒙古工业大学 | Common-path interference measurement device for generated optical aberration of liquid-crystal spatial light modulator |
-
2018
- 2018-07-27 CN CN201810840167.7A patent/CN109001904B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102109414A (en) * | 2010-12-15 | 2011-06-29 | 深圳大学 | Method and device for calibrating phase modulation of spatial light modulators by utilizing heterodyne interference |
| CN102540531A (en) * | 2012-01-11 | 2012-07-04 | 中国科学院长春光学精密机械与物理研究所 | Transitional grey level driving method for increasing response speed of liquid crystal wave-front corrector |
| CN102566114A (en) * | 2012-01-11 | 2012-07-11 | 中国科学院长春光学精密机械与物理研究所 | GPU (graphic processing unit)-assisted transition grayscale driving method of liquid crystal wave-front corrector |
| CN203365108U (en) * | 2013-07-08 | 2013-12-25 | 内蒙古工业大学 | Common-path interference measurement device for generated optical aberration of liquid-crystal spatial light modulator |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109739033A (en) * | 2019-02-25 | 2019-05-10 | 中国科学院光电技术研究所 | A kind of liquid-crystal aberration correcting method of no Wavefront detecting |
| CN111489686A (en) * | 2020-03-31 | 2020-08-04 | 深圳市奥拓电子股份有限公司 | Display screen thermal effect compensation adjustment display device, method and system |
| CN112116887A (en) * | 2020-11-23 | 2020-12-22 | 南京芯视元电子有限公司 | Display chip flatness correction system of LCoS spatial light modulator |
| CN113242416A (en) * | 2021-04-23 | 2021-08-10 | 苏州天准科技股份有限公司 | Method for correcting gray scale nonlinearity of digital projector, storage medium and projection system |
| CN113242416B (en) * | 2021-04-23 | 2022-06-21 | 苏州天准科技股份有限公司 | Method for correcting gray scale nonlinearity of digital projector, storage medium and projection system |
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