CN110389020A - Detection method of spatial light modulator - Google Patents

Abstract

The invention relates to a detection method of a spatial light modulator. The detection method includes the following steps: providing illumination light; receiving the illumination light by a spatial light modulator to generate image light, and the spatial light modulator includes a plurality of modulation units; projecting the image light to generate a projection image, wherein the projection A plurality of pixel points of the image correspond one-to-one to the plurality of modulation units; capturing the projected image to generate a captured image; and analyzing deviation angles of the plurality of modulation units of the spatial light modulator according to the captured image.

Description

Detection method of spatial light modulator

technical field

The invention relates to a detection method of a spatial light modulator.

Background technique

Existing projection systems generally include a light source device, a spatial light modulator (such as an LCOS spatial light modulator or a DMD spatial light modulator) and a projection lens. The light source device emits light in three colors such as red, green and blue. The image data performs image modulation on the light emitted by the light source device, and the projection lens projects the image light output by the spatial light modulator to display the projected image. However, the existing projection system may have a low contrast ratio, There is a need to improve.

In the projection system, the spatial light modulator as a signal modulation component directly determines the effect of the projected picture. Currently commonly used spatial light modulators are LCD and DMD. Starting from the working principle of the spatial light modulator, each microstructure unit on the spatial light modulator, such as liquid crystal or micro-mirror, corresponds to a pixel on the screen, and the control circuit controls the The transmittance or reflectance of each structural unit to the illuminating light modulates the display content of each pixel, thereby loading and displaying the entire screen information. When there is a quality problem with the spatial light modulator, it will affect the brightness and color of the projected picture, specifically manifested as low brightness, uneven brightness, and uneven color. When the spatial light modulator has a material or structural problem (such as a large error in the transmittance of the liquid crystal material and the reflectivity of the micro-mirror), the image displayed through the modulation of the spatial light modulator will have an overall brightness error, thus The brightness of the displayed image is low. The response results of the structural units corresponding to each pixel on the spatial light modulator are difficult to be completely consistent with the same driving signal. When the response results of some structural units have large errors, the pixels corresponding to the structural units display abnormally. Display abnormalities at the level of pixels are manifested as uneven brightness and color unevenness of the display screen.

However, in the production process of projection equipment, there has been no effective means to detect the quality of the spatial light modulator. After the production of the equipment is completed, whether there is a problem with the spatial light modulator can be found during the test process. If there is a problem, the projection device needs to be disassembled and the spatial light modulator replaced by the production line. Among them, as shown in Figure 1, Figure 1 is a flow chart of finding the cause according to the problem of the display screen. The brightness reduction and color impurity in a large range caused by the spatial light modulator can often point to multiple devices. In order to determine the cause of the error The reason is that the spatial light modulator needs to detect each device that may have an impact, which is a cumbersome process and costs a lot of unnecessary labor costs. In general, the device that causes brightness and color unevenness at the pixel level is the spatial light modulator. The modulation units on the spatial light modulator correspond to the pixels of the display screen one by one. As the current display resolution is getting higher and higher, the number of modulation units of the spatial light modulator reaches millions or more. Therefore, the modulator During the preparation process, it is difficult to ensure the consistency of the illumination light modulation by each modulation unit. Then, when unevenness in brightness and color occurs, it is difficult to ensure the reliability of the projection device only by replacing the spatial light modulator.

In addition, with the development of projection display technology, the requirements for brightness, color and contrast of projection images are getting higher and higher. At present, the etendue of the laser light source or the laser-fluorescent hybrid light source is smaller than that of the light bulb light source, so the projection lens can collect the projection beam with a smaller aperture, while reducing the loss of divergent light energy and the influence of stray light, and improving the projection image quality. Brightness and contrast have become the main direction of the current projection technology development. However, as the etendue decreases, the light receiving angle of the lens decreases, which also has a certain impact on the brightness and color unevenness. Among them, when the LCD is used as the spatial light modulator, the light collected by the lens is shown in Figure 2. The transmittance of the liquid crystal light valve to the illumination light indicates the brightness of the corresponding pixel on the display screen. When the transmittance of the liquid crystal is relatively standard When there is an error in the value, the light collected by the lens will deviate accordingly. This deviation is not sensitive to the etendue, that is, there is basically no difference in brightness unevenness with different etendue. However, due to the smaller aperture of the lens, the contrast parameter of the projected image is improved. When the DMD is used as the spatial light modulator, the principle of lens light collection with different etendues is shown in Figure 3. When the DMD is used as the spatial light modulator, the deflection angle value of the micromirror represents the brightness of the corresponding pixel on the display screen. Dark, when there is a certain error α in the deflection angle of the mirror relative to the standard value, the diffracted beam will be deflected by 2α accordingly. At the same time, the movement of the diffracted beam will make the lens collect different wavelengths of light. More sensitive, that is, brightness and color unevenness are more obvious when the etendue is small. Therefore, it is very important and practical to test the spatial light modulator during the production process of projection equipment to understand the degree of brightness and color unevenness caused by the spatial light modulator.

The more important issue is that as the DMD flip angle increases from ±12° to ±17°, the beam angle that the DMD can accommodate becomes larger. But a large flip angle means that the F number of the lens (that is, F#) becomes smaller (that is, the emission angle of the lens becomes larger), so the contrast ratio (about 600) of the projector with LED as the light source is very poor. When the projection equipment using laser or laser fluorescence as the light source adopts the same specification of DMD, the angle of illumination light can be made relatively small (that is, the emission angle is small), and the F number of the lens can be enlarged accordingly, so a higher contrast can be obtained ( about 3500). When the modulation process of some pixels in the spatial light modulator is abnormal, the non-laser light source (bulb or LED) projection equipment is not sensitive to these pixel-level abnormalities due to its low contrast, and the spatial light modulator can be considered to be working normally. ; However, in laser or laser phosphor projection systems, the contrast ratio is very high, and the abnormality of some pixels will lead to more obvious picture unevenness, that is, the spatial light modulator does not meet the product requirements. Therefore, for high-contrast projection systems, it is of great significance to propose a reliable method for detecting spatial light modulators.

Contents of the invention

In order to understand the degree of brightness and/or color unevenness caused by the spatial light modulator, the present invention provides a detection method for the spatial light modulator.

A detection method for a spatial light modulator, comprising the following steps:

provide lighting;

A spatial light modulator receives the illumination light to generate image light, and the spatial light modulator includes a plurality of modulation units;

Projecting the image light to generate a projected image, wherein a plurality of pixels of the projected image correspond to the plurality of modulation units one by one;

capturing the projected image to generate a captured image; and

Analyzing deviation angles of the plurality of modulation units of the spatial light modulator according to the captured image.

Compared with the prior art, in the detection method, by capturing and analyzing the captured image of the projection image generated by the spatial light modulator modulating the illumination light, the multiple modulation units of the spatial light modulator can be known. deviation angle, so as to understand the degree of brightness and/or color unevenness caused by the spatial light modulator, and then determine whether the spatial light modulator can be used or what kind of projection system is suitable for the spatial light modulator. purpose of effective use.

Description of drawings

Figure 1 is a flow chart of finding causes based on display screen problems.

FIG. 2 is a schematic diagram of light collection by a lens when an LCD is used as a spatial light modulator.

FIG. 3 is a schematic diagram of the principle of lens light collection with different etendues when the DMD is used as the spatial light modulator.

Fig. 4 is a flow chart of the detection method of the spatial light modulator of the present invention.

FIG. 5 is a schematic structural diagram of a detection device using the detection method shown in FIG. 4 .

FIG. 6 is a brief flow chart and schematic diagram of the preprocessing steps.

Fig. 7 is a schematic diagram of the specific logic flow of the detection method of the present invention.

FIG. 8 is a schematic diagram of the process and principle of using the detection device shown in FIG. 5 to determine uneven phenomena.

FIG. 9 and FIG. 10 are schematic diagrams of image illuminance distribution obtained according to the captured images of two embodiments.

FIG. 11 is a schematic diagram of the process and principle of using the detection device shown in FIG. 5 when the resolution of the photographing device is smaller than the resolution of the projected image.

Explanation of main component symbols

Detection device 100

light source 101

lighting system 102

Spatial Light Modulator 103

projection lens 104

screen 105

Camera 106

Data processing device 107

Steps S1-S5

The following specific embodiments will further illustrate the present invention in conjunction with the above-mentioned drawings.

Detailed ways

The method for detecting the spatial light modulator proposed by the present invention can be used for the detection of the spatial light modulator on the production line of the laser fluorescence projection equipment. The detection of the spatial light modulator reduces the probability of problems in the projection equipment and improves the projection quality. Product reliability.

Please refer to FIG. 4 and FIG. 5 , FIG. 4 is a flow chart of the detection method of the spatial light modulator of the present invention, and FIG. 5 is a schematic structural diagram of the detection device 100 using the detection method shown in FIG. 4 . The detection device 100 includes a light source 101 , an illumination system 102 , a spatial light modulator 103 , a projection lens 104 , a screen 105 , a photographing device 106 , and a data processing device 107 .

The detection method includes the following steps S1-S5.

Step S1, providing illumination light. Wherein, the light source 101 is used to emit light source light. The illumination system 102 is located on the light path of the light source, and is used for converting the light source into the illumination light. It can be understood that the light source 101 may be a laser light source, such as a blue laser light source. In one embodiment, the illumination system 102 may include a wavelength conversion device, a relay lens, a dodging device, etc., and the wavelength conversion device may be a color wheel for receiving a part of the blue laser light emitted by the light source and The received light (such as red fluorescent light, green fluorescent light or yellow fluorescent light) is generated, and another part of the blue laser light and the received light are jointly provided to the spatial light modulator 103 as the illumination light. In one embodiment, when the light source includes blue, red and green laser light sources, the illumination system may not include a wavelength conversion device, but may include optical elements such as a relay lens and a uniform light device, The blue, red and green lasers are used as the illumination light and provided to the spatial light modulator 103 .

Step S2, the spatial light modulator 103 receives the illumination light to generate image light, and the spatial light modulator 103 includes a plurality of modulation units. Specifically, the spatial light modulator 103 is located on the optical path where the illumination light is located, so as to receive the illumination light and generate image light. It can be understood that when the spatial light modulator is a DMD chip, the modulation unit is a DMD micromirror.

Step S3 , projecting the image light to generate a projected image, wherein a plurality of pixels of the projected image correspond to the plurality of modulation units one by one. Specifically, the projection lens 104 is used to project the image light emitted by the spatial light modulator 103 to generate the projected image on the screen 105 .

Step S4, capturing the projected image to generate a captured image. Wherein, the photographing device 106 is used to photograph the projected image to generate the photographed image, and the photographing device 106 may be a CCD camera. It can be understood that, since the resolution of the CCD camera can be higher than the resolution of the projection system composed of the light source 101, the illumination system 102, the spatial light modulator 103, the projection lens 104 and the screen 105, by The captured image can obtain the illuminance value and color tristimulus value of each pixel on the projected image.

Step S5 , analyzing deviation angles of the plurality of modulation units of the spatial light modulator 103 according to the captured image. Specifically, the data processing device 107 is configured to receive the captured image, and analyze the quality of the projected image according to the captured image, so as to obtain deviation angles of the plurality of modulation units of the spatial light modulator 103 . The data processing device 107 may be a computer program (instruction) that is stored in a storage medium and can run on a processor, such as a terminal control program, etc., and of course may also include other hardware parts, such as a screen, buttons, communication devices Wait, I won't repeat them here. Wherein, the storage medium can be hard disk, internal memory, plug-in hard disk, smart memory card (Smart Media Card, SMC), secure digital (Secure Digital, SD) card, flash memory card (Flash Card), at least one disk storage device components, flash memory devices, or other volatile solid-state storage devices are not limited to the above. The processor can be a central processing unit (Central Processing Unit, CPU), and can also be other general-purpose processors, digital signal processors (Digital Signal Processor, DSP), application specific integrated circuits (Application Specific Integrated Circuit, ASIC), off-the-shelf Programmable gate array (Field-Programmable Gate Array, FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc., and not limited to the above.

It can be understood that the detection method further includes the step of installing the spatial light modulator 103 before step S2 and the step of preprocessing the illumination light before installing the spatial light modulator 103 .

Specifically, please refer to FIG. 6 . FIG. 6 is a flowchart and schematic diagram of the preprocessing steps. The step of described pretreatment comprises the following steps:

using the projection lens 104 to project the received illumination light;

using the photographing device 106 to photograph the projected image of the illumination light;

The uniformity detection is performed on the captured image projected by the illumination light. Specifically, the data processing device 107 or the naked eye may be used to perform uniformity detection on the captured image projected by the illumination light. If the captured image projected by the illumination light is uniform, proceed to the installation of the spatial light modulator 103 and subsequent steps S2-S5, if the captured image projected by the illumination light is Inhomogeneous, then replace the light source 101 that emits the illumination light, the optical elements between the illumination light and the projected image (such as the optical elements in the illumination system 102: lens, uniform light device, etc.; projection lens 104; or projection screen 105) and at least one of the photographing device 106, until the image projected by the illumination light is uniform.

It can be understood that the purpose of the above preprocessing steps is to ensure that the illumination light received by the spatial light modulator 103 is uniform and that the projection lens 104 and/or the photographing device will not have any influence on the detection method. defect. When it is found that the illumination light is uniform after the preprocessing step, the step of installing the spatial light modulator 103 may be performed, so as to further perform the steps S2-S5. If the uniform illumination light cannot be obtained due to experimental conditions, then the illuminance and color tristimulus value of each pixel of the projected illumination light can be recorded for use in the data processing and analysis of step S5.

Furthermore, in one embodiment, in the step S5, if it is determined based on the captured image that the spatial light modulator 103 has a defect (for example, the deviation angle and/or illuminance of a certain number of modulation units exceeds a predetermined value ), then it is judged that the detection result of the spatial light modulator 103 is unqualified; if it is judged that the detection result of the spatial light modulator is qualified (such as a certain number of If the deviation angle and/or illuminance of the modulation unit are within the predetermined value range), the detection method also includes: adjusting the F number of the projection lens 104 or replacing the projection lens 104 with a different F number, and repeating the steps of the detection method Steps S1-S5, so as to judge again whether the detection result of the spatial light modulator 103 is qualified or not. Wherein, in the step of adjusting the F-number of the projection lens 104 or replacing the projection lens 104 with a different F-number, the F-number increases gradually. Specifically, according to the above steps, the specific logic flow of the detection method can be shown in FIG. 7 . It can be understood that the term F-number represents the aperture number of the lens, usually recorded as F#, such as F3.5, F5.6, etc. Specifically, the F-number of a lens is equal to the focal length f' of the lens and the aperture diameter of the lens The ratio of D, i.e. f'/D, therefore, the F number of the projection lens 104 is the aperture number of the projection lens 104, and is equal to the ratio of the focal length of the projection lens 104 to the aperture diameter of the projection lens 104 .

Further, in the above steps, mainly considering that the F-numbers of the projection lenses used by different projection systems are different, in order to ensure that the detection results can accurately determine whether the spatial light modulator 103 to be tested meets the requirements of the projection system, first use The projection lens 104 with a relatively small F number (such as F#1.7) forms an image (that is, obtains a projected image), and judges whether there is a problem in the picture taken by the shooting device 106 in this case. If the picture is uniform, it proves that the spatial light modulator 103 receives light. It works fine for large angles (i.e. large launch angles). On this premise, replace the projection lens 104 with a larger F number (such as F#3.5), use the detection system to image again, and then detect whether there is a pixel defect in the imaged image. If obvious pixel defects appear after the replacement of the projection lens 104 (that is, the test result is unqualified), it proves that the spatial light modulator 103 does not meet the requirements of the projection system when the light collection angle is small (that is, the emission angle is large). Require.

Further, for different projection systems, there are differences in the acceptable deflection angle of the modulation unit of the spatial light modulator 103 from the standard value. In one embodiment, quantitative analysis of the deviation angle of the modulation unit of the spatial light modulator 103 The detection method used may include the following steps:

using the light source 101 and the illumination system 102 to provide the illumination light with parallel illumination beams;

Adjusting the F number of the projection lens 104 or replacing the projection lens 104 with a different F number until at least one pixel of the projection image is completely darkened; and

Use the photographing device 106 to capture the projection image of the at least one pixel darkened, and analyze the at least one modulation unit corresponding to the at least one pixel according to the captured image of the at least one pixel darkened projection image Angle of deviation.

Specifically, in the above-mentioned step of quantitatively analyzing the deviation angle of the modulation unit of the spatial light modulator 103, the optical radiation field L of the image light formed after the illumination light passes through the multiple modulation units of the spatial light modulator 103 The spatial angles α and β of the diffracted beam corresponding to each modulation unit conform to the following formula:

L(α,β−β ₀ )=0, α ² +β ² ≥1.

Wherein, in the above-mentioned formula, β ₀ is the incident angle, and λ is the wavelength of light, and the integral range of described space angle α, β is provided by F number, will above formula to described wavelength λ and described space angle α, β Integrate to obtain the relationship f(α, β) between the brightness of each pixel and the spatial angle; when the deflection angle of a modulation unit deviates (Δα, Δβ), there is an angular translation of the diffracted beam spatial angle α, β relative to the normal value , then the relationship between the pixel brightness and the spatial angle corresponding to the modulation unit that has deviations becomes f(α+Δα, β+Δβ), which is brought into the measured data and fitted to obtain the values of Δα and Δβ, then the The deviation composite angle δ of the modulation unit is expressed as cosδ=cosΔαcosΔβ.

In another embodiment, the detection method may further include: a step of calculating flip angles of the plurality of modulation units of the spatial light modulator according to the captured image and using a law of reflection.

It can be understood that the detection method can be used for the detection of the spatial light modulator on the production line of the projection equipment, and the parameters that need to be paid attention to during the detection process of the spatial light modulator include: the efficiency of the spatial light modulator and the efficiency of the spatial light modulator. degree of inhomogeneity. The following describes how the detection device 100 and the detection method used therein further describe the specific scheme steps of the detection of the efficiency of the spatial light modulator 103 , brightness unevenness, color unevenness, and the use of different resolution imaging devices 106 .

(1) Detection of the efficiency of the spatial light modulator 103

It can be understood that the step of preprocessing may also include: a step of recording the original illuminance and color tristimulus value of each pixel of the captured image projected by the illumination light and the step of recording according to the captured image Steps of obtaining the original illuminance of each pixel from the image projected by the above-mentioned illumination light and calculating the average original illuminance I of all pixels. Correspondingly, in order to realize the detection of the efficiency of the spatial light modulator 103, the detection method may further include the following steps performed by the data processing device 107:

Obtaining the actual illuminance of each pixel according to the captured image;

Calculate the average illuminance I' of all pixels of the captured image according to the actual illuminance of each pixel;

calculating the efficiency E(%) of the spatial light modulator according to the average illuminance and the average original illuminance;

The efficiency E(%) is compared with a preset value to determine whether the efficiency of the spatial light modulator is up to standard.

Understandably, the average illuminance And described efficiency E (%) meets following formula respectively:

Among them, in is the actual illuminance of any pixel, and _N is the number of pixels.

In general, considering that in order to ensure that the spatial light modulator 103 can fully receive the illumination light, the spot size of the illumination light is slightly larger than the size of the spatial light modulator 103. At this time, the efficiency of the spatial light modulator 103 is about 60%/0.85=70.6 %, when the calculated efficiency of the measured spatial light modulator 103 is lower than this value and the difference is large (such as less than 50%, which can be set according to actual needs), it is considered that the measured spatial light modulator 103 The quality is not up to standard, that is, the test result of efficiency is unqualified.

(2) Detection of uneven brightness of the spatial light modulator 103

Generally speaking, the non-uniform phenomenon of the projected image caused by the spatial light modulator 103 is manifested as abnormal display of some pixels. The process of using the detection device 100 to judge the uneven phenomenon is shown in FIG. The original illuminance and color tristimulus value of each pixel are recorded to detect uneven brightness of the spatial light modulator 103; after the spatial light modulator 103 to be tested is installed in the detection device 100, it is projected on the screen The image, and then the illuminance distribution of the image and the color tristimulus value of each pixel are obtained by the photographing device 106 to judge the phenomenon of uneven brightness and color caused by the spatial light modulator 103 .

Specifically, the detection method may also include the following steps performed by the data processing device 107:

Acquiring the actual illuminance and/or color tristimulus value of each pixel according to the captured image;

Calculate the number M of pixel abnormal points, the distribution density of pixel abnormal points and/or the conspicuous degree C (%) of a single pixel abnormal point according to the actual illuminance and/or color tristimulus value of each pixel; and

Judging whether the projected image of the spatial light modulator meets the uniformity requirement according to the number M of abnormal pixel points, the distribution density of abnormal pixel points and/or the obvious degree of abnormal point of a single pixel, wherein, the abnormal point of a single pixel is The obvious degree of point C (%) satisfies the following formula:

i _k is the actual illuminance value of each pixel, N is the number of pixels, μ is the average illuminance of all pixels.

In one embodiment, the schematic diagram of the illuminance distribution of the image obtained according to the captured image is shown in FIG. The projected image will therefore produce some random pixel anomalies. The generation of pixel outliers affects the brightness uniformity of the image. The degree of brightness unevenness is reflected in the following aspects: the number M of pixel abnormal points, the distribution density of pixel abnormal points, and the degree of obviousness of a single pixel abnormal point. The apparent degree C (%) of the pixel abnormal point is measured by the ratio of the root mean square and the average value of the illuminance values of all pixels (that is, the formula for calculating C (%)).

According to the above, it can be seen that the larger the value of C, the more obvious the pixel abnormal point is. When the conspicuousness of individual pixel outliers is small and negligible, the number of pixel outliers has a major impact on the brightness unevenness. Assuming that the number of pixel abnormal points is required to be limited within m in the entire projection screen, when M>m, it is considered that the degree of brightness unevenness is obvious, which does not meet the requirements of the projection system. When M<m, the distribution density of abnormal pixel points is the main factor affecting the phenomenon of uneven brightness. As shown in Figure 9, when the distribution of abnormal pixel points is relatively scattered and there is no concentration of multiple pixels, it can be considered that the phenomenon of uneven brightness is not obvious, which meets the requirements of the projection system. As shown in FIG. 10 , when the distribution of abnormal pixel points is concentrated, it is considered that the unevenness of brightness is obvious, which does not meet the requirements of the projection system.

(3) Detection of color unevenness of the spatial light modulator 103

It can be understood that the degree of color unevenness of the projected image caused by the spatial light modulator 103 is difficult to judge through direct observation, and the color tristimulus value (X _k , Y _k , Z _k ) of each pixel can be obtained according to the captured image. ), and calculate the degree of color unevenness of the projected image. Specifically, the detection method also includes the following steps:

The color coordinates (x _{k , y k ) of each pixel are calculated according to the color tristimulus value (X k , Y k , Z k ) of each pixel, and the color coordinates (x k , y k ) satisfy the following formula} :

The color uniformity of the spatial light modulator is judged to meet the requirements by comparing the color coordinate difference values of adjacent pixel elements.

(4) Detection using different resolution shooting devices 106

In step S4 of the detection method, when the resolution of the photographing device 106 is smaller than the resolution of the projection image, the photographing device can be used to photograph different regions of the projection image at least twice, and the Images captured at least twice are image-combined to generate the captured image.

Specifically, with the continuous development of projection technology, the resolution of projected images is getting higher and higher, and it is difficult to always ensure that the resolution of the photographing device 106 is higher than the resolution of projected images. As shown in Figure 11, when the resolution of the photographing device 106 is smaller than that of the projection device, multiple shots of the local information of different positions of the projected image can be taken, and the overall picture method of synthesizing the projected image through image data processing can be adopted, and then in the above embodiment On this basis, the illuminance and color tristimulus value of each pixel of the projection image are measured, and it is judged whether the spatial light modulator to be tested meets the requirements of the projection system.

The above is only an embodiment of the present invention, and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process conversion made by using the description of the present invention and the contents of the accompanying drawings, or directly or indirectly used in other related technologies fields, all of which are equally included in the scope of patent protection of the present invention.

Claims (13)

1. a kind of detection method of spatial light modulator, it is characterised in that: the detection method includes

Illumination light is provided；

Spatial light modulator receives the illumination light and generates image light, and the spatial light modulator includes multiple modulation units；

It projects described image light and generates projected image, wherein multiple pixels of the projected image and the multiple modulation unit It corresponds；

It shoots the projected image and generates shooting image；And

The misalignment angle of multiple modulation units according to spatial light modulator described in the shooting image analysis.

2. the detection method of spatial light modulator as described in claim 1, it is characterised in that: the projection described image light produces In the step of raw projected image, the image light that the spatial light modulator issues project generating by projection lens The projected image, the projection lens has current F number, described according to spatial light modulator described in the shooting image analysis Multiple modulation units misalignment angle the step of in, if according under the projection lens of current F number the shooting image judgement The testing result of the spatial light modulator is qualification, the then detection method further include: adjust the projection lens F number or The projection lens of different F numbers is replaced, and repeats each step of the detection method, thus described in judgement is different under F number again Whether the testing result of spatial light modulator is qualified, wherein the F number or the different F numbers of replacement of the adjustment projection lens Projection lens the step of in, the F number is gradually increased.

3. the detection method of spatial light modulator as claimed in claim 2, it is characterised in that: the detection method further include:

The illumination light for having parallel illuminating bundle is provided；

It adjusts the F number of the projection lens or replaces the projection lens of different F numbers at least one pixel of the projected image Point is completely dimmed；And

At least one pixel described in the shooting image analysis of the projected image dimmed according at least one described pixel is corresponding At least one modulation unit misalignment angle.

4. the detection method of spatial light modulator as claimed in claim 3, it is characterised in that: the illumination light is via the sky Between optical modulator multiple modulation units after the light radiation field L diffraction corresponding with each modulation unit of described image light that is formed Space Angle α, β of light beam meets following formula:

L(α,β-β₀)=0, α²+β²≥1；

Wherein, β₀For incidence angle, λ is the wavelength of light, and the limit of integration of Space Angle α, β is provided by F number, by above formula pair The wavelength X and Space Angle α, β integral obtain the relationship f (α, β) of each pixel brightness and Space Angle；

When deviation (Δ α, Δ β) occurs in the deflection angle of a modulation unit, diffracted beam Space Angle α, β is relative to normal value There are an angle translational movements, then pixel brightness corresponding for the modulation unit for deviation occur and space angular dependence Just become f (α+Δ α, β+Δ β), brings measure data fitting into and obtain the value of Δ α and Δ β, then the deviation of the modulation unit Compound angle δ is expressed as cos δ=cos Δ α cos Δ β.

5. the detection method of spatial light modulator as described in claim 1, it is characterised in that: the detection method includes:

The flip angle of multiple modulation units of the spatial light modulator is calculated according to the shooting image and using reflection law Degree.

6. the detection method of spatial light modulator as described in claim 1, it is characterised in that: the detection method further include The spatial light modulator receives the step of the installation spatial light modulator before the step of illumination light generation image light Suddenly.

7. the detection method of spatial light modulator as claimed in claim 6, it is characterised in that: the detection method further include What is carried out before installing the spatial light modulator carries out pretreated step, the pretreated step packet to the illumination light Include following steps:

The illumination light is received to be projected；

The image projected to the illumination light is shot；

The image projected to the illumination light of the shooting carries out uniformity detection, if the illumination light of the shooting The image projected be it is uniform, then the installation spatial light modulator and subsequent step are carried out, if the shooting The image that the illumination light is projected be it is non-uniform, then replace the light source for issuing the illumination light, the illumination light to institute At least one of optical element and the filming apparatus between projected image are stated, until the figure that the illumination light is projected It seem uniform.

8. the detection method of spatial light modulator as claimed in claim 6, it is characterised in that: the detection method further include What is carried out before installing the spatial light modulator carries out pretreated step, the pretreated step packet to the illumination light Include following steps:

The illumination light is received to be projected；

The image projected to the illumination light is shot；

The original luminance of each pixel of the image projected to the illumination light of the shooting records；And

The image that the illumination light according to the shooting is projected obtains the original luminance of each pixel and calculates all The average original luminance of pixel

9. the detection method of spatial light modulator as claimed in claim 8, it is characterised in that: the detection method further include:

The practical illumination of each pixel is obtained according to the shooting image；

The average illumination of image all pixels point is shot described in practical luminance calculation according to each pixel

The efficiency E (%) of the spatial light modulator, the effect are calculated according to the average illumination and the average original luminance Rate E (%) meets following formula:

The efficiency E (%) is compared with preset value to judge whether the efficiency of the spatial light modulator is up to standard.

10. the detection method of spatial light modulator as described in claim 1, it is characterised in that: the detection method further include:

The practical illumination and/or color tristimulus values of each pixel are obtained according to the shooting image；

Practical illumination and/or color tristimulus values according to each pixel calculate number M, the pixel of pixel abnormal point The obvious degree C (%) of abnormal point distribution density and/or single pixel abnormal point；And

According to the number M of the pixel abnormal point, the obvious degree of pixel abnormal point distribution density and/or single pixel abnormal point Judge whether the projected picture of the spatial light modulator meets the requirement of uniformity,

Wherein, the obvious degree of the single pixel abnormal point C (%) meets following formula

i_kIt is the practical brightness value of each pixel, N is the quantity of pixel, and μ is the average illumination of all pixels point.

11. the detection method of spatial light modulator as claimed in claim 10, it is characterised in that: the detection method is also wrapped It includes:

Color tristimulus values (X according to each pixel_k, Y_k, Z_k) chromaticity coordinates (x of each pixel is calculated_k, y_k), it is described Chromaticity coordinates (x_k, y_k) meet following formula:

Compare the chromaticity coordinates difference of adjacent pixels to judge that the color homogeneity of the spatial light modulator meets the requirements.

12. the detection method of spatial light modulator as described in claim 1, it is characterised in that: shoot the projected image and produce In the step of raw shooting image, described image is shot using filming apparatus, when the resolution ratio of the filming apparatus is less than the throwing When the resolution ratio of shadow image, shoot the different zones of the projected image at least twice using the filming apparatus, to it is described extremely Few image shot twice carries out image synthesis to generate the shooting image.

13. the detection method of spatial light modulator as described in claim 1, it is characterised in that: the spatial light modulator is Dmd chip, the modulation unit are DMD micro mirror.