Disclosure of Invention
In order to solve the problems, the invention provides an acoustic thin film precision laser processing device which comprises an industrial control host, a feeding module, a discharging module, a cleaning module, a microscopic module and a processing module.
The system is also provided with an analysis module and an audio module;
the industrial control host is connected with a feeding module, a discharging module, a cleaning module, a microscopic module and a processing module, wherein the feeding module is used for feeding the acoustic film so as to carry out laser processing of the acoustic film; the blanking module is used for blanking the acoustic film after the processing is finished;
the cleaning module is arranged behind the feeding module and is used for cleaning the ascending film; the micro-module is used for collecting the surface morphology of the acoustic film and sending the collected surface morphology data to the industrial control host;
the processing module is used for carrying out laser processing on the acoustic film according to the collected surface morphology data;
the industrial control host is connected with the analysis module and the audio module;
the audio module is used for driving the acoustic thin film to vibrate and collecting the frequency response curve of the acoustic thin film; the analysis module is used for calculating a processing height threshold according to the acquired frequency response curve and surface morphology data; and the processing module carries out precise laser processing on the acoustic film according to the processing height threshold value.
Further:
the acoustic film is an earphone diaphragm, and the acoustic film structure comprises a diaphragm base material and an alloy coating; wherein the vibrating diaphragm base material is plastic or paper, and the alloy plating layer is made of aluminum alloy, titanium alloy, beryllium alloy or platinum alloy.
Further:
the cleaning module comprises an air gun and a compressed air tank, wherein the air gun is connected with the compressed air tank, the air gun is a porous air gun, and the porous air gun blows compressed air towards the acoustic film when in use, so that dust and impurities on the surface of the acoustic film are cleaned.
Further:
the micro module and the processing module work cooperatively;
the microscopic module comprises an illumination light source, a confocal microscope, a light shielding plate, a photoelectric detector, a sample stage and a displacement stage; the confocal microscope comprises an ocular, an objective lens, a dichroic mirror and a small hole; the ocular, the aperture, the dichroic mirror and the objective lens are sequentially arranged from top to bottom;
the processing module comprises a femtosecond laser source, a spatial light modulator and a light source converter;
the illumination light source and the femtosecond laser source are connected to a light source converter, and the light source converter selects one of the illumination light source and the femtosecond laser source to enter the confocal microscope through adjustment;
after entering the confocal microscope, the light is reflected into the objective lens by the dichroic mirror and reaches the surface of the sample stage; light on the surface of the sample is transmitted into the small hole through the dichroic mirror and then reaches the photoelectric detector;
the sample platform is a lifting sample platform, and drives the sample to lift in the vertical direction; the confocal microscope is arranged on the displacement table, and the displacement table drives the confocal microscope to move in the horizontal two-dimensional direction.
Further:
the light shielding plate is arranged between the small hole of the confocal microscope and the photoelectric detector; the light shielding plate is linked with the light source converter, and when the light source converter selects the illumination light source to enter the confocal microscope, the light shielding plate is opened, so that light can reach the photoelectric detector;
when the light source converter selects the femtosecond laser source to enter the confocal microscope, the light shielding plate is closed, so that light cannot reach the photoelectric detector;
the illumination source and the femtosecond laser source have the same wavelength.
Further:
the femtosecond laser emitted from the femtosecond laser source is modulated by the spatial light modulator, so that the femtosecond laser and the illumination light source are focused on the same point after passing through the confocal microscope.
Further, the precise laser processing method of the acoustic thin film, which uses the precise laser processing device of the acoustic thin film, comprises the following steps:
step 1, film feeding:
the acoustic films after coating are sequentially transferred by the feeding module and reach the cleaning module;
step 2, cleaning the film:
the cleaning module blows compressed gas towards the acoustic film, so that dust and impurities on the surface of the acoustic film are purged;
step 3, film installation:
the purged acoustic film is clamped by the clamp holder and is arranged on the sample table, and the sample table is connected with the audio module, so that the audio module can drive the acoustic film to sound; the installed acoustic film is transferred to a processing station;
step 4, measuring before processing:
the audio module drives the acoustic film to sound, and detects a frequency response curve of the acoustic film; the collected frequency response curve is sent to an industrial control host;
the microscopic module collects surface three-dimensional morphology data of the acoustic film and sends the surface three-dimensional morphology data to the industrial control host;
the analysis module acquires a frequency response curve from the industrial control host, and compares the frequency response curve with a pre-stored standard curve to obtain a differential curve; the analysis module acquires surface three-dimensional morphology data from the industrial control host and extracts curved surface coordinate data of the surface three-dimensional morphology data;
the analysis module calculates a processing height threshold according to the differential curve, screens the area with the height exceeding the processing height threshold in the curved surface coordinate data, and marks the area as a processing area; the analysis module sends the screened processing area to the industrial control host;
step 5, femtosecond laser processing:
the processing module carries out in-situ processing on the acoustic film through femtosecond laser, and the processing area screened in the step 4 is thinned and thinned to a height threshold value;
step 6, measuring after processing:
the audio module drives the acoustic film to sound, and detects a frequency response curve of the acoustic film; the collected frequency response curve is sent to an industrial control host;
the analysis module acquires a frequency response curve from the industrial control host, and compares the frequency response curve with a pre-stored standard curve to obtain a differential curve; the analysis module calculates whether the difference curve meets the requirements, if so, the acoustic film is processed to be qualified, and if not, the steps 4-6 are repeated until the acoustic film is processed to be qualified;
step 7, film blanking:
and (3) blanking the acoustic films qualified in processing through a blanking module, and classifying and storing the acoustic films independently according to the times of repeatedly executing the step (5) during blanking.
Further:
in the step 4, the frequency range of the collected frequency response curve is 5-40000Hz; the three-dimensional morphology is that the confocal microscope images samples with different heights by adjusting the height of a sample stage or adjusting the focal length of an objective lens, and the imaging of multiple layers is spliced and inverted to obtain three-dimensional morphology data of the acoustic film;
the analysis module calculates a processing height threshold according to the differential curve, screens the area with the height exceeding the processing height threshold in the curved surface coordinate data, marks the area as a processing area, and specifically comprises the following steps:
the differential curve is obtained by performing a difference between the actually acquired frequency response curve and the standard curve; calculating the area of the differential curve to obtain the area S of the differential curve; the method for calculating the area S of the differential curve comprises the steps of firstly dividing the differential curve into 5 areas which are a low frequency area, a medium-low frequency area, a medium-high frequency area and a high frequency area;
calculating the area of the differential curve in each region, namely a low frequency region S 1 Low and medium frequency regions S 2 Intermediate frequency region S 3 Medium and high frequency region S 4 And a high frequency region S 5 ;
;
Wherein k is 1 、k 2 、k 3 、k 4 、k 5 As a constant coefficient, S is calculated 1 、S 2 、S 3 、S 4 、S 5 Absolute value of area of each region;
s is equal to the preset area S 0 Comparing if S > S 0 Judging that the acoustic film cannot be processed, directly discarding the acoustic film, and executing the step 7;
if S is less than or equal to S 0 The calculation method of the processing height threshold Z comprises the following steps:
;
wherein Z is 0 For presetting the processing height threshold value, S 0 Is a preset area;
thus, for the same acoustic film, the greater S, the smaller Z, the lower the processing height threshold that needs to be thinned, and the more areas that are thinned; the smaller S is, the larger Z is, the higher the machining height threshold value required to be thinned is, and the thinner area is also fewer;
the 5 regions are divided in such a manner that they are divided empirically or equally spaced according to the logarithm of the frequency.
Further:
in step 5, the light source converter switches the light source to a femtosecond laser source; the laser emitted from the femtosecond laser source reaches the same focus as the illumination light source after being modulated by the spatial light modulator;
and adjusting the positions of the displacement table and the sample table to enable the femtosecond laser to carry out cold processing on the surface of the acoustic film, removing a layer of material on the surface of the film by utilizing high energy of the femtosecond laser, and enabling the thickness of the acoustic film after removal to reach a height threshold value.
In step 5, the power P of the femtosecond laser n The calculation is performed according to the following formula:
;
wherein P is n Z is the processing power of n points on the acoustic film n P is the actual height of the n-point on the acoustic film 0 For reference processing power, k 6 Is a coefficient.
The beneficial effects of the invention are as follows:
the invention uses the femtosecond laser combined with the confocal microscope to realize the in-situ precision processing of the acoustic film, is suitable for the high-end fields with high requirements on the vibrating diaphragm, such as high-precision flat headphones, capacitance headphones and the like, greatly improves the yield of the vibrating diaphragm, reduces the cost and improves the economic value.
According to the invention, the acoustic performance is acquired before the acoustic film is processed, and the processing parameters are determined according to the acquired acoustic performance, so that the independent processing of any acoustic film is realized, the processing precision is high, the processing effect is good, the consistency of the acoustic film is ensured, and the yield of products is improved.
According to the invention, the actual surface morphology of the acoustic film is measured by using the confocal microscope in actual processing, the thickness to be subtracted is calculated according to the difference value between the actual surface morphology and the expected surface morphology, the power of the laser is set accordingly, the processing is more accurate, and the acoustic performance of the processed product is better.
The femtosecond laser is cold processing, adopts laser with the same wavelength as the illumination light source, and is provided with the spatial light modulator to enable the processing laser and the illumination laser to be at the same focus, thereby reducing the calculation and control difficulty during processing, simplifying equipment and improving efficiency.
Detailed Description
Example 1:
referring to fig. 1 to 6, the invention provides an acoustic thin film precision laser processing device, which comprises an industrial control host 6, a feeding module 1, a discharging module 2, a cleaning module 3, a micro module 4 and a processing module 5.
The system is also provided with an analysis module and an audio module;
the industrial control host 6 is connected with the feeding module 1, the discharging module 2, the cleaning module 3, the microscopic module 4 and the processing module 5, and the feeding module 1 is used for feeding the acoustic film so as to carry out laser processing of the acoustic film; the blanking module 2 is used for blanking the acoustic film after the processing is finished;
the cleaning module 3 is arranged behind the feeding module 1 and is used for cleaning the ascending film; the micro module 4 is used for collecting the surface morphology of the acoustic film and sending the collected surface morphology data to the industrial control host 6;
the processing module 5 is used for carrying out laser processing on the acoustic film according to the collected surface morphology data;
the industrial control host 6 is connected with the analysis module and the audio module;
the audio module is used for driving the acoustic thin film to vibrate and collecting the frequency response curve of the acoustic thin film; the analysis module is used for calculating a processing height threshold according to the acquired frequency response curve and surface morphology data; the processing module 5 performs precision laser processing on the acoustic thin film according to the processing height threshold.
Further:
the acoustic film is an earphone diaphragm, and the acoustic film structure comprises a diaphragm base material and an alloy coating; wherein the vibrating diaphragm base material is plastic or paper, and the alloy plating layer is made of aluminum alloy, titanium alloy, beryllium alloy or platinum alloy.
Further:
the cleaning module 3 comprises an air gun and a compressed air tank, wherein the air gun is connected with the compressed air tank, the air gun is a porous air gun, and the porous air gun blows compressed air towards the acoustic film when in use, so that dust and impurities on the surface of the acoustic film are cleaned.
Further:
the micro module 4 and the processing module 5 work cooperatively;
the microscope module 4 comprises an illumination light source, a confocal microscope, a light shielding plate 34, a photoelectric detector 33, a sample stage 31 and a displacement stage 32; the confocal microscope includes an eyepiece 38, an objective lens 37, a dichroic mirror 36, and an aperture 35; eyepiece 38, aperture 35, dichroic mirror 36 and objective 37 are mounted in order from top to bottom;
the processing module 5 comprises a femtosecond laser source, a spatial light modulator and a light source converter;
the illumination light source and the femtosecond laser source are connected to a light source converter, and the light source converter selects one of the illumination light source and the femtosecond laser source to enter the confocal microscope through adjustment;
after entering the confocal microscope, the light is reflected by the dichroic mirror 36 into the objective 37 and reaches the surface of the sample stage 31; light from the sample surface is transmitted through dichroic mirror 36 into aperture 35 before reaching photodetector 33;
the sample table 31 is a lifting sample table 31, which drives the sample to lift in the vertical direction; the confocal microscope is mounted on a displacement stage 32, and the displacement stage 32 drives the confocal microscope to move in a horizontal two-dimensional direction.
Further:
a light shielding plate 34 is arranged between the aperture 35 of the confocal microscope and the photodetector 33; the light shielding plate 34 is linked with the light source converter, and when the light source converter selects the illumination light source to enter the confocal microscope, the light shielding plate 34 is opened to enable the light to reach the photoelectric detector 33;
when the light source converter selects the femtosecond laser source to enter the confocal microscope, the light shielding plate 34 is closed, so that light cannot reach the photoelectric detector 33;
the illumination source and the femtosecond laser source have the same wavelength.
Further:
the femtosecond laser emitted from the femtosecond laser source is modulated by the spatial light modulator, so that the femtosecond laser and the illumination light source are focused on the same point after passing through the confocal microscope.
Example 2:
the precise laser processing method of the acoustic film, which uses the precise laser processing device of the acoustic film, comprises the following steps:
step 1, film feeding:
the acoustic films after coating are sequentially transferred by the feeding module 1 and reach the cleaning module 3;
step 2, cleaning the film:
the cleaning module 3 blows compressed gas towards the acoustic membrane, so that dust and impurities on the surface of the acoustic membrane are purged;
step 3, film installation:
the cleaned acoustic film is clamped by the clamp holder and is mounted on the sample table 31, and the sample table 31 is connected with the audio module, so that the audio module can drive the acoustic film to sound; the installed acoustic film is transferred to a processing station;
step 4, measuring before processing:
the audio module drives the acoustic film to sound, and detects a frequency response curve of the acoustic film; the collected frequency response curve is sent to an industrial control host 6;
the microscopic module 4 collects the surface three-dimensional shape data of the acoustic film and sends the surface three-dimensional shape data to the industrial control host 6;
the analysis module acquires a frequency response curve from the industrial control host 6, and compares the frequency response curve with a pre-stored standard curve to obtain a differential curve; the analysis module acquires surface three-dimensional morphology data from the industrial control host 6 and extracts curved surface coordinate data of the surface three-dimensional morphology data;
the analysis module calculates a processing height threshold according to the differential curve, screens the area with the height exceeding the processing height threshold in the curved surface coordinate data, and marks the area as a processing area; the analysis module sends the screened processing area to the industrial control host 6;
step 5, femtosecond laser processing:
the processing module 5 carries out in-situ processing on the acoustic film through femtosecond laser, and thins the processing area screened in the step 4 to a height threshold value;
step 6, measuring after processing:
the audio module drives the acoustic film to sound, and detects a frequency response curve of the acoustic film; the collected frequency response curve is sent to an industrial control host 6;
the analysis module acquires a frequency response curve from the industrial control host 6, and compares the frequency response curve with a pre-stored standard curve to obtain a differential curve; the analysis module calculates whether the difference curve meets the requirements, if so, the acoustic film is processed to be qualified, and if not, the steps 4-6 are repeated until the acoustic film is processed to be qualified;
step 7, film blanking:
and (3) blanking the acoustic films which are qualified in processing through a blanking module 2, and classifying and storing the acoustic films according to the times of repeatedly executing the step (5) during blanking.
Further:
in the step 4, the frequency range of the collected frequency response curve is 5-40000Hz; the three-dimensional morphology is that the confocal microscope images samples with different heights by adjusting the height of the sample stage 31 or adjusting the focal length of the objective lens 37, and the imaging of multiple layers is spliced and inverted to obtain three-dimensional morphology data of the acoustic film;
the analysis module calculates a processing height threshold according to the differential curve, screens the area with the height exceeding the processing height threshold in the curved surface coordinate data, marks the area as a processing area, and specifically comprises the following steps:
the differential curve is obtained by performing a difference between the actually acquired frequency response curve and the standard curve; calculating the area of the differential curve to obtain the area S of the differential curve; the method for calculating the area S of the differential curve comprises the steps of firstly dividing the differential curve into 5 areas which are a low frequency area, a medium-low frequency area, a medium-high frequency area and a high frequency area;
calculating the area of the differential curve in each region, namely a low frequency region S 1 Low and medium frequency regions S 2 Intermediate frequency region S 3 Medium and high frequency region S 4 And a high frequency region S 5 ;
;
Wherein k is 1 、k 2 、k 3 、k 4 、k 5 As a constant coefficient, S is calculated 1 、S 2 、S 3 、S 4 、S 5 Absolute value of area of each region;
s is equal to the preset area S 0 Comparing if S > S 0 Judging that the acoustic film cannot be processed, directly discarding the acoustic film, and executing the step 7;
if S is less than or equal to S 0 The calculation method of the processing height threshold Z comprises the following steps:
;
wherein Z is 0 For presetting the processing height threshold value, S 0 Is a preset area;
thus, for the same acoustic film, the greater S, the smaller Z, the lower the processing height threshold that needs to be thinned, and the more areas that are thinned; the smaller S is, the larger Z is, the higher the machining height threshold value required to be thinned is, and the thinner area is also fewer;
the 5 regions are divided in such a manner that they are divided empirically or equally spaced according to the logarithm of the frequency.
Further:
in step 5, the light source converter switches the light source to a femtosecond laser source; the laser emitted from the femtosecond laser source reaches the same focus as the illumination light source after being modulated by the spatial light modulator;
the positions of the displacement table 32 and the sample table 31 are adjusted, so that the femtosecond laser carries out cold processing on the surface of the acoustic film, a layer of material on the surface of the film is removed by utilizing high energy of the femtosecond laser, and the thickness of the acoustic film after the removal reaches a height threshold value.
In step 5, the power P of the femtosecond laser n The calculation is performed according to the following formula:
;
wherein P is n Z is the processing power of n points on the acoustic film n P is the actual height of the n-point on the acoustic film 0 For reference processing power, k 6 Is a coefficient.
Example 3:
this embodiment describes a specific implementation of the device of the present invention in a flat-panel earphone.
Firstly, the vibrating diaphragm of the flat earphone is flat, and in actual use, polyester fiber or paper base material is adopted, and titanium alloy or beryllium alloy is evaporated on the surface; the thickness of the coating film is 30-100 mu m; the film with the thickness is difficult to accurately process in a common processing mode; but the thickness of the removed material can be accurately controlled by using a femtosecond laser for processing. The actual processing process is as follows:
step 1, film feeding:
the acoustic films after coating are sequentially transferred by the feeding module 1 and reach the cleaning module 3; the thickness of the coating film is 95 mu m; however, in the actual coating, the thickness is difficult to ensure to be 95 μm absolutely, so that the thickness is increased to be 10-20 μm thicker than the target thickness in the actual coating;
step 2, cleaning the film:
the cleaning module 3 blows compressed gas towards the acoustic membrane, so that dust and impurities on the surface of the acoustic membrane are purged; at this time, it is ensured that the surface of the acoustic film is free from dust affecting the subsequent microscopic measurement and laser processing, while ensuring that water or oil remains when the film surface is free from plating or cutting.
Step 3, film installation:
the cleaned acoustic film is clamped by the clamp holder and is mounted on the sample table 31, and the sample table 31 is connected with the audio module, so that the audio module can drive the acoustic film to sound; the installed acoustic film is transferred to a processing station;
step 4, measuring before processing:
the audio module drives the acoustic film to sound, and detects a frequency response curve of the acoustic film; the collected frequency response curve is sent to an industrial control host 6;
the microscopic module 4 collects the surface three-dimensional shape data of the acoustic film and sends the surface three-dimensional shape data to the industrial control host 6;
the analysis module acquires a frequency response curve from the industrial control host 6, and compares the frequency response curve with a pre-stored standard curve to obtain a differential curve; the analysis module acquires surface three-dimensional morphology data from the industrial control host 6 and extracts curved surface coordinate data of the surface three-dimensional morphology data;
the standard curve may be a Harman curve, a straight curve, or other custom-made special curves.
The analysis module calculates a processing height threshold according to the differential curve, screens the area with the height exceeding the processing height threshold in the curved surface coordinate data, and marks the area as a processing area; the analysis module sends the screened processing area to the industrial control host 6;
the differential curve is obtained by performing a difference between the actually acquired frequency response curve and the standard curve; calculating the area of the differential curve to obtain the area S of the differential curve; the method for calculating the area S of the differential curve comprises the steps of firstly dividing the differential curve into 5 areas which are a low frequency area, a medium-low frequency area, a medium-high frequency area and a high frequency area;
calculating the area of the differential curve in each region, namely a low frequency region S 1 Low and medium frequency regions S 2 Intermediate frequency region S 3 Medium and high frequency region S 4 And a high frequency region S 5 ;
;
Wherein k is 1 、k 2 、k 3 、k 4 、k 5 As a constant coefficient, S is calculated 1 、S 2 、S 3 、S 4 、S 5 Absolute value of area of each region;
s is equal to the preset area S 0 Comparing if S > S 0 Judging that the acoustic film cannot be processed, directly discarding the acoustic film, and executing the step 7;
if S is less than or equal to S 0 The calculation method of the processing height threshold Z comprises the following steps:
;
wherein Z is 0 For presetting the processing height threshold value, S 0 Is a preset area;
thus, for the same acoustic film, the greater S, the smaller Z, the lower the processing height threshold that needs to be thinned, and the more areas that are thinned; the smaller S is, the larger Z is, the higher the machining height threshold value required to be thinned is, and the thinner area is also fewer;
the 5 regions are divided in such a manner that they are divided empirically or equally spaced according to the logarithm of the frequency.
In the embodiment, logarithmic equidistant division is adopted, namely, the abscissa of the whole curve is changed into logarithmic coordinate values, and equidistant division is carried out according to the logarithm.
Step 5, femtosecond laser processing:
the processing module 5 carries out in-situ processing on the acoustic film through femtosecond laser, and thins the processing area screened in the step 4 to a height threshold value;
step 6, measuring after processing:
the audio module drives the acoustic film to sound, and detects a frequency response curve of the acoustic film; the collected frequency response curve is sent to an industrial control host 6;
the analysis module acquires a frequency response curve from the industrial control host 6, and compares the frequency response curve with a pre-stored standard curve to obtain a differential curve; the analysis module calculates whether the difference curve meets the requirements, if so, the acoustic film is processed to be qualified, and if not, the steps 4-6 are repeated until the acoustic film is processed to be qualified;
step 7, film blanking:
and (3) blanking the acoustic films which are qualified in processing through a blanking module 2, and classifying and storing the acoustic films according to the times of repeatedly executing the step (5) during blanking.
When being stored separately, the product is stored as a first-grade product which is processed once, is stored as a second-grade product which is processed twice, and is stored as a third-grade product which is processed three times; and if high-end equipment cannot be manufactured after processing for more than three times, the works are stored in a obsolete way and are used for producing low-end products.
The description of the foregoing embodiments has been provided for the purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to the particular embodiment, but, where applicable, may be interchanged and used with the selected embodiment even if not specifically shown or described. The same elements or features may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.
Example embodiments are provided so that this disclosure will be thorough, and will fully convey the scope to those skilled in the art. Numerous details are set forth, such as examples of specific parts, devices, and methods, in order to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to one skilled in the art that the exemplary embodiments may be embodied in many different forms without the use of specific details, and neither should be construed to limit the scope of the disclosure. In certain example embodiments, well-known processes, well-known device structures, and well-known techniques are not described in detail.
The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms "comprises" and "comprising" are inclusive and, therefore, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed and illustrated, unless specifically indicated. It should also be appreciated that additional or alternative steps may be employed.