CN118641159B - Laser speckle contrast value calibration method and device based on mixed light source - Google Patents
Laser speckle contrast value calibration method and device based on mixed light source Download PDFInfo
- Publication number
- CN118641159B CN118641159B CN202411120741.3A CN202411120741A CN118641159B CN 118641159 B CN118641159 B CN 118641159B CN 202411120741 A CN202411120741 A CN 202411120741A CN 118641159 B CN118641159 B CN 118641159B
- Authority
- CN
- China
- Prior art keywords
- light source
- speckle
- laser
- speckle contrast
- incoherent
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Landscapes
- Testing Of Optical Devices Or Fibers (AREA)
- Photometry And Measurement Of Optical Pulse Characteristics (AREA)
Abstract
The method utilizes a laser light source and an incoherent light source to form speckle patterns with different speckle contrast values by adjusting the power ratio of the two light sources, and comprises the following specific steps: patterning using only incoherent light sources and measuring the speckle contrast value, ensuring a theoretical speckle contrast of 0%; patterning using only a laser light source and measuring a reference speckle contrast value; setting speckle contrast to different theoretical values by adjusting incoherent light source power, and measuring and recording; and (3) calibrating the speckle tester by comparing the measured value with the theoretical value. The method can remarkably improve the accuracy and reliability of the measurement result of the speckle tester, and particularly provides a more accurate calibration means for the typical speckle contrast value range of 1% -30%. The invention fills the technical blank of lacking special speckle tester calibration equipment in the market.
Description
Technical Field
The invention relates to the field of laser display speckle measurement, in particular to a calibration method and device for calibrating a measurement result of a laser display speckle tester.
Background
The laser display is a display technology adopting laser as a light source, compared with other display technologies, the laser display has the largest color expression space, the color gamut coverage rate can reach more than 90% of the color space which can be identified by human eyes theoretically, the laser display also has the advantages of high energy utilization rate, environmental protection, long service life, wide product coverage range and the like, and becomes one of the display technologies with the most development prospect, and the market also presents a rapidly growing situation.
The speckle phenomenon is a phenomenon in which when laser light passes through a diffuse reflection or a transparent diffuser at the surface of the diffuser, a large number of randomly distributed bright and dark spots can be observed in the light field at or near the surface of the diffuser. The speckle phenomenon reduces the contrast and uniformity of the image, causing visual impact to the observer. The use of a speckle tester for speckle measurement is crucial for detecting and assessing laser display quality.
The existing calibration method is used in the 5-2 th part of the Chinese national standard GB/T43590.502-2024 laser display device: speckle contrast optical measurement methods have been described, including calibration methods where the speckle contrast values are two values of 0% and 100%, whereas there is a lack of a corresponding calibration method in the intermediate value region of 0% to 100%. The speckle contrast value of a typical laser display product is basically kept within the range of 1% -15%, and the highest speckle contrast value in the class of the laser display product is about 27%, so that the accuracy of the speckle contrast measurement of the current laser display product cannot be effectively ensured by using the existing calibration method.
Disclosure of Invention
In order to solve the problem of lack of calibration equipment for a speckle tester at present, the invention provides a laser speckle contrast value calibration method and device based on a mixed light source, so that the speckle tester can be calibrated in the use and detection process, and the purpose of ensuring the accuracy and reliability of the test result of the speckle tester is realized.
The technical scheme adopted by the invention is as follows: a laser speckle contrast value calibration method based on a mixed light source is characterized in that: there are two light sources: the power of the laser light source and the incoherent light source can be respectively adjusted, and speckle patterns with different speckle contrast values are formed by different power ratios of the two light sources; and collecting the speckle pattern by using a speckle tester to be tested, calculating speckle contrast, and comparing and calibrating by using theoretical speckle contrast values under different light source power ratios.
The invention creatively uses a non-laser light source in the test of the speckle tester, provides an innovative concept of a mixed light source, mixes different light sources with the laser light source, adopts the non-coherent light source as the mixed light source for detecting the tested laser speckle tester, and obtains the theoretical speckle contrast as the calibration basis. The light emitted by the incoherent light source has no fixed phase relationship and therefore does not produce interference effects. Thus, when the incoherent light source is mixed with a laser light source, the standard deviation of the total light intensity of the mixed light source does not vary significantly.
Further design, the calibration steps are as follows:
s1: turning off the laser light source, and only guiding out the incoherent light source to a transmission type scattering sheet or a diffuse reflection screen to form a pattern;
S2: collecting patterns formed on a transmission type scattering sheet or a diffuse reflection screen by using a speckle tester to be tested, measuring the current speckle contrast value, wherein the theoretical speckle contrast at the moment is 0%, and carrying out zero-resetting calibration on the speckle tester to be tested if the difference exists;
S3: closing an incoherent light source, and only guiding out the laser light source to a transmission type scattering sheet or a diffuse reflection screen to form a pattern;
S4: collecting patterns formed on a transmission type scattering sheet or a diffuse reflection screen by using a speckle tester to be tested, measuring the current speckle contrast value, transmitting the current speckle contrast value into a main control computer to receive the value, and taking the value as a reference value for laser speckle calibration in subsequent calibration ；
S5: recording a current luminance value using a speckle tester under test；
S6: substituting the reference value into a speckle contrast calculation formula, calculating and recording the current standard deviation value；
S7: from 0 to a reference valueAliquoting into n parts, i.e、、、……、、；
S8: driving the laser source, incoherent source power to vary such that the speckle contrast of the calibration device is set toMarking as theoretical speckle contrast;
s9: collecting patterns formed on a transmission type scattering sheet or a diffuse reflection screen by using a speckle tester to be tested, and measuring the current speckle contrast value;
S10: repeating the steps S8 and S9, and respectively measuring and recording the speckle tester to be tested when the calibrating device is set as 、、……、Actual speckle contrast value at that time;
S11: and comparing the actually measured speckle contrast with the theoretical speckle contrast, and calibrating the speckle tester.
Further, the photoelectric performance monitoring module can be used for S5 operation, so that more accurate brightness value monitoring is realized, and the proportion of the mixed light source is more accurate;
The diffuse reflection screen acts by reflecting light out to form a speckle pattern;
The transmission type scattering sheet has the function of generating a speckle pattern by scattering light beams, and the generated speckle pattern has the characteristic of high contrast and is suitable for high-precision speckle measurement.
The incoherent light source refers to a uniformly illuminated LED light source or other uniformly illuminated incandescent, xenon or halogen lamp. A uniform LED light source is generally used, and the power adjustment is convenient.
The average light intensity formula of the mixture of the laser light source and the incoherent light source is as follows:
；
Wherein: is the average light intensity of the laser light source, Average intensity of incoherent light source;
Speckle contrast for hybrid light sources The formula is as follows:
；
Wherein: Is the standard deviation of the total light intensity of the mixed light source, because the uniformity of the incoherent light source is better Mainly from standard deviation of light intensity of laser light sourceI.e.；Is the average intensity of the mixed light source.
If the average intensity of the laser source is not changedEnhancing the average intensity of incoherent lightAverage value of total light intensityAn increase; the fluctuation degree of the laser speckle pattern does not change greatly, namely the standard deviation of the total light intensity of the mixed light sourceRemains substantially unchanged, so the speckle contrastAnd (3) lowering.
When choosing an incoherent light source to mix with a laser light source, it must be ensured that at least some of the wavelength ranges in the spectra of the two light sources overlap to ensure coverage and matching of the spectra. Currently incoherent light sources generally select LED light sources.
According to the simulation formula of mixing a laser light source and an incoherent light sourceAnd matching the power of the laser light source and the incoherent light source so as to calibrate the laser speckle contrast value.
The device for calibrating the laser speckle contrast value based on the mixed light source, which is manufactured according to the detection method, comprises the following components: the device comprises a mixed light source device, a transmission type scattering sheet or a diffuse reflection screen and a photoelectric performance monitoring module; light emitted by the mixed light source device enters the speckle tester to be tested through a transmission type scattering sheet or a diffuse reflection screen; the photoelectric performance monitoring module is used for monitoring and calibrating the brightness and chromaticity of the mixed light source.
The hybrid light source device comprises: the hybrid light source device comprises: comprising two light sources: a laser light source, an incoherent light source, a driver and a main control computer of the incoherent light source and the incoherent light source respectively; the light source is used for realizing the mixed light source with different light source powers, and the incoherent light source and the laser light source are respectively irradiated on the transmission type scattering sheet or the diffuse reflection screen. The main control machine respectively adjusts and controls the drivers of the laser light source and the incoherent light source to control the output light power of the laser light source and the incoherent light source, so that the two light sources are mixed on the transmission type scattering sheet or the diffuse reflection screen.
The hybrid light source device comprises: the hybrid light source device comprises: comprising two light sources: a laser light source, an incoherent light source, a driver, an integrating sphere and a main control computer of the incoherent light source and the incoherent light source; the integrating sphere is provided with two light inlets which are respectively connected with the laser light source and the incoherent light source, the incoherent light source and the laser light source are led into the integrating sphere, the integrating sphere is provided with two light outlets, one light outlet is connected with the photoelectric performance monitoring module, the other light outlet is connected with the transmission type scattering sheet, and the rear end of the transmission type scattering sheet is provided with a speckle tester to be tested. The main control machine respectively adjusts and controls the output power of the laser light source and the incoherent light source, the two light sources are mixed in the integrating sphere, and the mixed light is output by the light outlet.
The laser light source irradiated on the transmission type scattering sheet or the diffuse reflection screen is a laser light source after beam expansion, and the pattern size formed by the irradiation of the laser light source after beam expansion on the transmission type scattering sheet is larger than the acquisition window of the speckle tester to be tested. Increased laser source illumination range. Ensures that the two light sources can be uniformly mixed.
According to the method for detecting the speckle tester by introducing the mixing of the incoherent light source and the laser light source, the accuracy and the reliability of the measurement result of the speckle tester can be remarkably improved. Aiming at the calibration of the intermediate value region of the speckle contrast value which cannot be related in the current standard, a more accurate calibration means is provided in the range of 1% -30% of the speckle contrast value of a typical laser display product.
The invention adopts the mixture of the laser light source and the incoherent light source, utilizes the incoherent property of the incoherent light source, and the light emitted by the incoherent light source has no fixed phase relation and can not generate interference effect. The standard deviation of the total light intensity of the hybrid light source does not vary significantly when the incoherent light source is mixed with the laser light source. By means of different power ratios of the two light sources, speckle patterns with different speckle contrast values can be generated, the calibration process is simplified, and the calibration of the speckle tester can be rapidly and accurately realized.
The invention can adopt a transmission type scattering sheet or a diffuse reflection screen to generate speckle patterns, and can select different devices according to different calibration requirements. If a large-scale (e.g., 0% -100%) relatively low-precision calibration is pursued, a form of directly illuminating the diffuse reflection screen with a mixed light source can be adopted; if a relatively high precision, relatively small range (e.g., 0% -30%) of calibration is sought, a hybrid light source integrating sphere transmissive diffuser may be used.
Aiming at the problem that the existing market lacks special calibration equipment of the speckle tester, the invention provides a complete and effective calibration method and device, and fills the technical blank.
Drawings
FIG. 1 is a schematic block diagram of the present invention
Fig. 2 is a schematic structural diagram of a calibration device for laser speckle contrast based on a hybrid light source and a transmissive diffuser according to embodiment 1
FIG. 3 is a schematic structural view of embodiment 2
FIG. 4 is a schematic diagram of a direct-lit hybrid light source device
FIG. 5 is a schematic diagram showing the structure of a device for calibrating the laser speckle contrast value based on a hybrid light source integrating sphere and a transmission type scattering sheet
FIG. 6 is a schematic diagram of three-color laser fiber coupling
FIG. 7 is an exemplary plot of calibration fit curves versus measured data points for a reference speckle value of 30% and a laser brightness of 500cd/m 2
FIG. 8 is a graph showing the relationship between the theoretical and measured speckle values when the reference speckle value is 30% and the laser brightness is 500cd/m 2
FIG. 9a is a pure laser source speckle pattern
FIG. 9b is a mixed light source speckle pattern
Wherein: the speckle tester comprises a speckle tester to be tested 201, a transmission type scattering sheet 202, a mixed light source device 203, a diffuse reflection screen 301, a laser light source 401, a light source 402 LED, a laser light source driver 403, a light source driver 404 LED, a main control computer 405, an integrating sphere 501, a first light outlet 502, a second light outlet 503, a first light inlet 504, a second light inlet 505, a baffle 506, a 507 photoelectric performance monitoring module, a red laser light source 601, a green laser light source 602, a blue laser light source 603 and a 604 optical fiber coupler.
Detailed Description
The present invention will be described in detail below with reference to the drawings so that those skilled in the art can more understand the present invention.
As shown in fig. 1, the present invention is a method for calibrating laser speckle contrast values based on a hybrid light source, which has two light sources: the power of the laser light source and the incoherent light source can be respectively adjusted, and speckle patterns with different speckle contrast values are formed by different power ratios of the two light sources; collecting speckle patterns by using a speckle tester to be tested, calculating speckle contrast, and comparing and calibrating theoretical speckle contrast values under different light source power ratios;
The calibration steps are as follows:
s1: turning off the laser light source, and only guiding out the incoherent light source to a transmission type scattering sheet or a diffuse reflection screen to form a pattern;
S2: after waiting for stabilization, collecting patterns formed on a transmission type scattering sheet or a diffuse reflection screen by using a speckle tester to be tested, measuring the current speckle contrast value, wherein the theoretical speckle contrast at the moment is 0%, and carrying out zero setting calibration on the speckle tester to be tested if the difference exists;
S3: closing an incoherent light source, and only guiding out the laser light source to a transmission type scattering sheet or a diffuse reflection screen to form a pattern;
s4: after waiting for stabilization, the pattern formed on the transmission type scattering sheet or the diffuse reflection screen is collected by using the speckle tester to be tested, the current speckle contrast value is measured, and the current speckle contrast value is transmitted into the main control machine to receive the value and is used as the reference value of laser speckle calibration in the subsequent calibration ；
S5: recording a current luminance value using a speckle tester under test；
S6: substituting the reference value into a speckle contrast calculation formula, calculating and recording the current standard deviation value；
S7: from 0 to a reference valueAliquoting into n parts, i.e、、、……、、；
S8: driving the laser source, incoherent source power to vary such that the speckle contrast of the calibration device is set toThe theoretical speckle contrast is recorded, generally, the power of one light source is kept unchanged, and the power of the other light source is changed, for example, under the condition that the laser power is unchanged, the incoherent light source is driven to change the speckle contrast value of the calibration device;
s9: collecting patterns formed on a transmission type scattering sheet or a diffuse reflection screen by using a speckle tester to be tested, and measuring the current speckle contrast value;
S10: repeating the steps S8 and S9, and respectively measuring and recording the speckle tester to be tested when the calibrating device is set as 、、……、Actual speckle contrast value at that time;
S11: and comparing the actually measured speckle contrast with the theoretical speckle contrast, and calibrating the speckle tester.
S5 operation can be performed by using the photoelectric performance monitoring module, so that more accurate brightness value monitoring is realized, and the proportion of the mixed light source is more accurate;
The diffuse reflection screen acts by reflecting light out to form a speckle pattern;
The transmission type scattering sheet has the function of generating a speckle pattern by scattering light beams, and the generated speckle pattern has the characteristic of high contrast and is suitable for high-precision speckle measurement. Compared with the reflective speckle measurement, the optical path of the transmissive speckle measurement can avoid the interference of some complex reflected optical paths on the speckle pattern.
The incoherent light source refers to an LED light source or other incandescent lamps, xenon lamps and halogen lamps which uniformly illuminate. LED light sources are typically used because of their lower cost and better LED light source driving stability.
The average light intensity formula of the mixture of the laser light source and the incoherent light source is as follows:
；
Wherein: is the average light intensity of the laser light source, Average intensity of incoherent light source;
Speckle contrast for hybrid light sources The formula is as follows:
；
Wherein: Is the standard deviation of the total light intensity of the mixed light source, because the uniformity of the incoherent light source is better Mainly from standard deviation of light intensity of laser light sourceI.e.；Is the average intensity of the mixed light source.
If the average intensity of the laser source is not changedEnhancing incoherent average light intensityAverage value of total light intensityAn increase; the fluctuation degree of the laser speckle pattern does not change greatly, namely the standard deviation of the total light intensity of the mixed light sourceRemains substantially unchanged, so the speckle contrastAnd (3) lowering.
When choosing an incoherent light source (e.g. an LED light source) to mix with a laser light source, it must be ensured that at least part of the wavelength ranges in the spectra of the two light sources overlap to ensure coverage and matching of the spectra.
According to the simulation formula of mixing a laser light source and an incoherent light sourceAnd matching the power of the laser light source and the incoherent light source so as to calibrate the laser speckle contrast value.
As shown in fig. 2, in embodiment 1.1, a calibration device for laser speckle contrast value based on a mixed light source is composed of a speckle tester 201 to be tested, a transmissive scattering sheet 202, and a mixed light source device 203, wherein mixed light emitted by the mixed light source device 203 enters the speckle tester 201 to be tested through the transmissive scattering sheet 202.
Because the LED light source has the characteristics of low cost, high stability and the like, the LED light source can be replaced by other incandescent lamps, xenon lamps and halogen lamps which are uniformly illuminated by taking the LED light source as an example, and the corresponding power adjustment method is only selected according to different lamps, so that the adjustment method is not repeated here.
There are two specific hybrid light source devices: as shown in fig. 4, the first hybrid light source device, also called a direct hybrid light source device, includes: a laser light source 401, an LED light source 402, a laser light source driver 403, an LED light source driver 404 and a main control computer 405.
The output power of the laser light source 401 and its stability are controlled by a laser light source driver 403; the output power of the LED light source 402 and its stability are controlled by the LED light source driver 404. The main control unit 405 controls the laser light source driver 403 and the LED light source driver 404 to realize power ratios of different light output powers, and finally forms a pattern on the transmissive diffusion sheet 202 (or the diffuse reflection screen 301).
As shown in fig. 5, the second hybrid light source device is a hybrid light source integrating sphere, also called an integrating sphere type hybrid light source device, and includes an integrating sphere 501, a first light outlet 502, a second light outlet 503, a first light inlet 504, a second light inlet 505, a baffle 506, a laser light source 401, a laser light source driver 403, an LED light source 402, an LED light source driver 404, a photoelectric performance monitoring module 507, a main control unit 405, a transmissive diffuser 202, and a speckle tester 201 to be tested.
The output power of the laser light source 401 and its stability are controlled by a laser light source driver 403; the output power of the LED light source 402 and its stability are controlled by the LED light source driver 404. The main control unit 405 controls the laser light source driver 403 and the LED light source driver 404 to realize power ratios of different light output powers. The laser light source 401 enters the first light inlet 504 of the integrating sphere, the LED light source 402 enters the second light inlet 505, and a baffle 506 is arranged at the rear ends of the first light inlet 504 and the second light inlet 505 in the integrating sphere and used for reflecting the light of the two light inlets to the inner wall of the integrating sphere for reflection and mixing, so that the aim of uniform mixing is achieved.
The type selection of the LED light source and the laser light source in the mixed light source device needs to ensure that the spectrums of the LED light source and the laser light source have coincident wavelength bands and are matched with the response curve function of the speckle tester to be tested.
The function of the transmissive diffuser is to form a speckle pattern by diffusing the light beam.
The laser light source is a relatively uniform beam after beam expansion.
Since there are two kinds of hybrid light source devices, embodiment 1 is further divided into the following two kinds:
As embodiment 1.1 of the present invention, the specific operation steps of the calibration device of the direct type hybrid light source device are as follows:
S1: turning off the laser light source 401, and guiding out only the LED light source 402 onto the transmissive diffusion sheet 202 to form a pattern;
S2: after the power of the light source is stabilized, the pattern formed on the transmission type scattering sheet 202 is collected by using the speckle tester 201 to be tested, the current speckle contrast value is measured, the theoretical speckle contrast at the moment is 0%, and if the difference exists, the speckle tester is subjected to zero-resetting linear calibration;
S3: turning off the LED light source 402, and directing only the laser light source 401 onto the transmissive diffuser 202 to form a pattern;
S4: after the power of the light source is stabilized, the pattern formed on the transmission type scattering sheet 202 is collected by using the speckle tester 201 to be tested, the current speckle contrast value is measured, and the value is set as the value on the main control computer 405 I.e. as a reference value for laser speckle calibration in subsequent calibration;
S5: recording the current luminance value using the speckle tester 201 under test ；
S6: substituting the reference value into a speckle contrast calculation formula, calculating and recording the current standard deviation value；
S7: from 0 to a reference valueAliquoting into n parts, i.e、、、……、、；
S8: while keeping the laser power unchanged, the LEDs are driven (the brightness of the LEDs to be set can be calculated by the following formula) so that the speckle contrast value of the calibration device is set to be；
；
S9: collecting a pattern formed on the transmissive scattering sheet 202 by using a speckle tester 201, and measuring a current speckle contrast value;
S10: repeating the steps S8, S9, and measuring the current reference device setting using the speckle tester 201 、、……、The actual speckle contrast value is recorded;
s11: and comparing the actually measured speckle contrast with the theoretical speckle contrast, and calibrating the speckle tester.
In example 1.2, compared with example 1.1, the direct type mixed light source device is changed into an integrating sphere type mixed light source device, the model of the integrating sphere selected in the example is iSphere-ISP300-LD, after the laser light source and the LED light source are LED into the integrating sphere, the mixed light source is LED out from the first light outlet and the second light outlet after full diffuse reflection, and a transmission type scattering sheet is arranged at the first light outlet, so that the mixed light source forms a pattern on the transmission type scattering sheet;
in this embodiment, compared with embodiment 1.1, the luminance value is monitored by using the photoelectric property monitoring module Compared with the built-in brightness measurement function of the speckle tester, the photoelectric performance monitoring module has higher precision, so that the calibration result is more accurate.
The integrating sphere comprises two light inlets (504 and 505) and two light outlets (502 and 503), wherein a baffle 506 is arranged at the two light inlets, and the inner wall of the integrating sphere is coated with standard diffuse reflection materials. The baffle plate has the function that light can not directly reach the light outlet, and full diffuse reflection is needed, so that the accuracy and the reliability of a measuring result are ensured.
Optionally, the optoelectronic performance monitoring module should be provided with a filter with the same response curve as the speckle tester under test, not labeled in the figure.
In example 1.2 of the present invention, the specific operation steps are as follows:
s1: turning off the laser light source 401, introducing the LED light source 402 into the integrating sphere, reflecting the light source on the inner wall of the integrating sphere, and forming a pattern on the transmissive scattering sheet 202;
S2: after the power of the light source is stabilized, the speckle tester 201 is used for collecting the pattern formed on the transmission type scattering 202, the current speckle contrast value is measured, the theoretical speckle contrast at the moment is 0%, and if the difference exists, the speckle tester is subjected to zero setting calibration;
s3: turning off the LED light source 402, only introducing the laser light source 401 into the integrating sphere, reflecting the light source on the inner wall of the integrating sphere, and forming a pattern on the transmissive scattering sheet 202;
S4: after waiting for stabilization, the speckle pattern of the pure laser light source formed on the transmissive scattering sheet 202 is collected by using the speckle tester 201 to be tested (as shown in fig. 9 a), the current speckle contrast value is measured to be 30%, and the value is set on the main control computer 405 30%, I.e. as a reference value for laser speckle calibration in subsequent calibration;
S5: recording the current brightness value using the photo-electric performance monitoring module 509 500Cd/m 2;
S6: substituting the reference value into a speckle contrast calculation formula, calculating and recording the current standard deviation value ；
S7: from 0 to a reference valueEqually divided into n parts, in this case n is 10, i.e、、、……、、；
S8: while keeping the laser power unchanged, the LEDs (the LED brightness is calculated by the following formula) are driven so that the reference device is set to；
；
S9: using a speckle tester 201 to collect a mixed light source speckle pattern formed on a transmissive scattering sheet 202 (as shown in fig. 9 b), and measuring a current speckle contrast value;
S10: repeating the steps S8, S9, and measuring and recording the reference device set as 、、……、Actual speckle contrast value at that time;
s11: and comparing the actually measured speckle contrast with the theoretical speckle contrast, and calibrating the speckle tester.
And (3) counting theoretical speckle contrast values and measured speckle contrast values under different LED brightness, and drawing a calibration fit curve and a comparison diagram of measured data points and the theoretical speckle values when the reference speckle value is 30% and the laser brightness is 500cd/m 2 as shown in figure 7. In order to calibrate the measured speckle contrast value, a comparison diagram of the theoretical speckle contrast value and the measured speckle contrast value as shown in fig. 8 may also be drawn, the measured speckle contrast value is calibrated to the theoretical speckle contrast value by a calibration data method (such as an inverse function of a fitting function, a table look-up method, etc.), and the calibration data method is set into the measured speckle tester.
Embodiment 2, an embodiment of a method and an apparatus for calibrating a laser speckle contrast value based on a directly illuminated hybrid light source and a diffuse reflection screen, as shown in fig. 3, includes: the speckle tester 201 to be tested, the diffuse reflection screen 301, the mixed light source device 203. The specific hybrid light source device is shown in fig. 4, and the operation procedure is the same as that of example 1.1.
In this example, compared with example 1.1, the transmission type scattering sheet was changed to a diffuse reflection screen, and the mixed light source was imaged on the speckle tester after reflection, unlike the transmission type scattering sheet which imaged light on the speckle tester after transmission.
The calibration method and the device of the embodiment accord with the part 5-2 of the national standard GB/T43590.502-2024 laser display device of China: the requirement for 100% speckle contrast value calibration in speckle contrast optical measurement method, i.e. maximum reference value。
Embodiment 3, the invention provides an embodiment of a method and a device for calibrating a color laser speckle contrast value based on an integrating sphere type mixed color light source and a transmission type scattering sheet, as shown in fig. 5 and 6, wherein compared with embodiment 1.2, the embodiment changes a laser light source from a single laser light source to a light source formed by coupling RGB three-color laser light through an optical fiber; the LED light source is replaced by a white LED light source.
The laser light source is formed by coupling a red laser light source 601, a green laser light source 602 and a blue laser light source 603 through an optical fiber coupler 604.
The specific operation steps of this embodiment are slightly different from those of embodiment 1.2, and it is necessary to calibrate the same color temperature of the laser light source and the LED light source and/or to provide the optical filter with the same response curve as the measured speckle tester in the optoelectronic performance monitoring module before all the operation steps of embodiment 1.2.
Example 4, which is an improvement on the basis of example 3 (color), is to implement a calibration method and device for primary color laser speckle contrast values, that is, example 4 provides an embodiment of a calibration method and device for primary color laser speckle contrast values based on an integrating sphere type hybrid color light source and a transmission type scattering sheet, the primary color laser speckle contrast values are calibrated by the color hybrid light source, and the device diagram is not drawn. In this embodiment, compared with embodiment 3, the optical-electrical performance monitoring module must be provided with a filter having the same response curve as the speckle tester to be tested.
Embodiment 5 the present invention provides an embodiment of a method and an apparatus for calibrating a laser speckle contrast value based on an integrating sphere type hybrid light source, and the apparatus is not drawn. In this example, compared to example 1.2, the transmissive diffuser was eliminated and the light from the integrating sphere was imaged directly onto the speckle tester under test.
This embodiment has the best calibration effect on the 0% speckle contrast value.
The calibration method and device of the embodiment 1/2/3/4/5 are in accordance with the Chinese national standard GB/T43590.502-2024 laser display device part 5-2: solution for 0% speckle contrast calibration in speckle contrast optical measurement method. Example 5 is a method and apparatus for optimal calibration of 0% speckle contrast values.
The calibration method and device of the embodiment 2 accords with the national standard GB/T43590.502-2024 laser display device part 5-2: the maximum reference value can be achieved as in example 2 for the 100% speckle contrast value calibration requirement in speckle contrast optical measurement methodIs used for the calibration of (a).
Claims (9)
1. A method for calibrating laser speckle contrast value based on a mixed light source is characterized by comprising the following steps: there are two light sources: the power of the laser light source and the incoherent light source is respectively adjusted, and speckle patterns with different speckle contrast values are formed by different power ratios of the two light sources; collecting speckle patterns by using a speckle tester to be tested, calculating speckle contrast, and comparing and calibrating theoretical speckle contrast values under different light source power ratios;
The calibration steps are as follows:
s1: turning off the laser light source, and only guiding out the incoherent light source to a transmission type scattering sheet or a diffuse reflection screen to form a pattern;
s2: collecting patterns formed on a transmission type scattering sheet or a diffuse reflection screen by using a speckle tester to be tested, and measuring the current speckle contrast value, wherein the theoretical speckle contrast at the moment is 0%;
S3: closing an incoherent light source, and only guiding out the laser light source to a transmission type scattering sheet or a diffuse reflection screen to form a pattern;
S4: collecting patterns formed on a transmission type scattering sheet or a diffuse reflection screen by using a speckle tester to be tested, measuring the current speckle contrast value, transmitting the current speckle contrast value into a main control computer to receive the value, and taking the value as a reference value for laser speckle calibration in subsequent calibration ；
S5: recording a current luminance value using a speckle tester under test；
S6: substituting the reference value into a speckle contrast calculation formula, calculating and recording the current standard deviation value；
S7: from 0 to a reference valueAliquoting into n parts, i.e、、、……、、；
S8: driving the laser source, incoherent source power to vary such that the speckle contrast of the calibration device is set toMarking as theoretical speckle contrast;
s9: collecting patterns formed on a transmission type scattering sheet or a diffuse reflection screen by using a speckle tester to be tested, and measuring the current speckle contrast value;
S10: repeating the steps S8 and S9, and respectively measuring and recording the speckle tester to be tested when the calibrating device is set as 、、……、Actual speckle contrast value at that time;
S11: and comparing the actually measured speckle contrast with the theoretical speckle contrast, and calibrating the speckle tester.
2. The method for calibrating laser speckle contrast values based on a hybrid light source of claim 1, wherein: the incoherent light source refers to a uniformly illuminated LED light source or other uniformly illuminated incandescent, xenon or halogen lamp.
3. The method for calibrating laser speckle contrast values based on a hybrid light source of claim 1, wherein: the average light intensity formula of the mixture of the laser light source and the incoherent light source is as follows:
；
Wherein: is the average light intensity of the laser light source, Average intensity of incoherent light source;
Speckle contrast for hybrid light sources The formula is as follows:
；
Wherein: Is the standard deviation of the total light intensity of the mixed light source, because the uniformity of the incoherent light source is better Mainly from standard deviation of light intensity of laser light sourceI.e.；Is the average intensity of the mixed light source.
4. A method for calibrating laser speckle contrast values based on a hybrid light source according to claim 1 or 2, characterized by: when choosing an incoherent light source to mix with a laser light source, it must be ensured that at least some of the wavelength ranges in the spectra of the two light sources overlap to ensure coverage and matching of the spectra.
5. A method for calibrating laser speckle contrast values based on a hybrid light source according to claim 1 or 3, characterized by: according to the simulation formula of mixing a laser light source and an incoherent light sourceAnd matching the power of the laser light source and the incoherent light source so as to calibrate the laser speckle contrast value.
6. A hybrid light source according to any one of claims 1-5 a calibration device manufactured by the calibration method of the laser speckle contrast value, characterized by comprising the following steps: the device comprises a mixed light source device, a transmission type scattering sheet or a diffuse reflection screen and a photoelectric performance monitoring module; light emitted by the mixed light source device enters the speckle tester to be tested through a transmission type scattering sheet or a diffuse reflection screen; the photoelectric performance monitoring module is used for monitoring and calibrating the brightness and chromaticity of the mixed light source.
7. The device for calibrating laser speckle contrast based on a hybrid light source of claim 6, wherein: the hybrid light source device comprises: comprising two light sources: a laser light source, an incoherent light source, a driver and a main control computer of the incoherent light source and the incoherent light source respectively; the light source is used for realizing the mixed light source with different light source powers, and the incoherent light source and the laser light source are respectively irradiated on the transmission type scattering sheet or the diffuse reflection screen.
8. The device for calibrating laser speckle contrast based on a hybrid light source of claim 6, wherein: the hybrid light source device comprises: comprising two light sources: a laser light source, an incoherent light source, a driver, an integrating sphere and a main control computer of the incoherent light source and the incoherent light source; the integrating sphere is provided with two light inlets which are respectively connected with the laser light source and the incoherent light source, the incoherent light source and the laser light source are led into the integrating sphere, the integrating sphere is provided with two light outlets, one light outlet is connected with the photoelectric performance monitoring module, the other light outlet is connected with the transmission type scattering sheet, and the rear end of the transmission type scattering sheet is provided with a speckle tester to be tested.
9. The device for calibrating laser speckle contrast based on a hybrid light source of claim 7, wherein: the laser light source irradiated on the transmission type scattering sheet or the diffuse reflection screen is a laser light source after beam expansion, and the pattern size formed by the irradiation of the laser light source after beam expansion on the transmission type scattering sheet is larger than the acquisition window of the speckle tester to be tested.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202411120741.3A CN118641159B (en) | 2024-08-15 | 2024-08-15 | Laser speckle contrast value calibration method and device based on mixed light source |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202411120741.3A CN118641159B (en) | 2024-08-15 | 2024-08-15 | Laser speckle contrast value calibration method and device based on mixed light source |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN118641159A CN118641159A (en) | 2024-09-13 |
| CN118641159B true CN118641159B (en) | 2024-10-25 |
Family
ID=92665306
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202411120741.3A Active CN118641159B (en) | 2024-08-15 | 2024-08-15 | Laser speckle contrast value calibration method and device based on mixed light source |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN118641159B (en) |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108007677A (en) * | 2017-12-27 | 2018-05-08 | 杭州远方光电信息股份有限公司 | A kind of laser projection speckle measurement system |
| CN109314764A (en) * | 2016-04-20 | 2019-02-05 | 雷瑟联合科技有限公司 | System and method for calibrating and correcting speckle contrast flowmeters |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2014032371A (en) * | 2012-08-06 | 2014-02-20 | Oxide Corp | Speckle contrast generator and speckle contrast evaluation device |
| CN114152413B (en) * | 2021-12-14 | 2022-10-28 | 上海唯视锐光电技术有限公司 | Method and device for testing dynamic speckles in laser display |
-
2024
- 2024-08-15 CN CN202411120741.3A patent/CN118641159B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109314764A (en) * | 2016-04-20 | 2019-02-05 | 雷瑟联合科技有限公司 | System and method for calibrating and correcting speckle contrast flowmeters |
| CN108007677A (en) * | 2017-12-27 | 2018-05-08 | 杭州远方光电信息股份有限公司 | A kind of laser projection speckle measurement system |
Also Published As
| Publication number | Publication date |
|---|---|
| CN118641159A (en) | 2024-09-13 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP3376187B1 (en) | Color testing method using standard illuminant color matching box | |
| KR101303365B1 (en) | Illumination system with multiple sets of light sources | |
| CN105571822A (en) | Calibrating device of two-dimensional color analyzer and calibration method | |
| CN105588639B (en) | A kind of standard sources is to color inspection box | |
| CN101389936A (en) | Color sensor | |
| US8723426B2 (en) | Systems and methods for sampling light produced from an LED array | |
| CN101527108A (en) | Measuring method for colorimetric parameters of LED display screen | |
| KR20090056858A (en) | Optical property measuring device | |
| CN105938016A (en) | Color measurement apparatus | |
| CN201034939Y (en) | Fluorescent powder excited measurement mechanism | |
| CN203688945U (en) | Laser backlight liquid crystal display device | |
| CN101191770B (en) | Luminous diode fluorescent powder emission spectrometry process | |
| CN118641159B (en) | Laser speckle contrast value calibration method and device based on mixed light source | |
| KR20070092577A (en) | Optical Sensing Systems and Color Analyzers With Such Optical Sensing Systems | |
| US6791682B2 (en) | Apparatus for inspecting display panel and method for inspecting the same | |
| CN207197666U (en) | A kind of novel color luminance meter | |
| Rykowski et al. | Novel approach for LED luminous intensity measurement | |
| CN111060204A (en) | Calibration device and method for color analyzer | |
| CN216559333U (en) | A light source for photometer calibration | |
| RU91761U1 (en) | REFERENCE DEVICE FOR TRANSFER OF THE SIZE OF THE UNITS OF COORDINATES OF COLOR OF SELF-LIGHTING OBJECTS | |
| CN111594809B (en) | Multifunctional color calibration system | |
| CN216349110U (en) | Uniform area light source | |
| CN114136440A (en) | Portable retroreflection luminosity and chromaticity combined measurement method and device | |
| CN114061768B (en) | Integrating sphere type light source color temperature calibration device and color temperature meter calibration method | |
| CN205811274U (en) | RGB LASER Light Source luminous power output Self Matching system |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |