Foldable glass and preparation method thereof

Abstract

The invention relates to the technical field of foldable glass, and discloses a foldable glass preparation method, which comprises: 1, carrying out punching cutting on a bending position of soda-lime glass by using a picosecond-level solid-state laser; 2, after cutting is completed, the soda-lime glass is immersed in an acid solution to be corroded, ultrasonic vibration is adopted to enable waste in a cutting area to fall off, and target glass is obtained. According to the preparation method, the length of the broken edge of the soda-lime glass can be reduced to be smaller than 3 microns, the transmittance of a soda-lime glass processing area is kept to be 95% or above, and the cutting yield of the soda-lime glass is increased. Meanwhile, the invention further provides foldable glass.

Description

Technical Field

[0001] The present invention relates to the technical field of foldable glass, and in particular to a foldable glass and a preparation method thereof. Background Art

[0002] The outermost layer of a mobile phone folding screen is a flexible screen, and there is a glass backplane under the flexible screen as the substrate for components such as capacitors. The hollowing process at the folding position of this glass backplane has always been a difficult problem in the industry. It is generally recognized in the industry that femtosecond lasers are required to process soda-lime glass with a thickness of less than 200 microns because femtosecond lasers are relatively "sharp". However, the prominent problem with femtosecond laser cutting is that due to the overly concentrated energy, soda-lime glass is prone to cracking or chipping, reducing the yield rate of the folding glass.

[0003] Compared with quartz glass and borosilicate glass, soda-lime glass has a higher coefficient of thermal expansion and cannot be cut with high-power lasers. Excessive power will cause the soda-lime glass to change color, while quartz glass and borosilicate glass can be cut with high-power lasers. Moreover, using lasers with different pulse widths will also affect soda-lime glass. If the pulse width of the laser is too small, it is easy to cause chipping at the cutting position of the soda-lime glass.

[0004] CN115448586A discloses a foldable glass and a preparation method thereof. The preparation method includes the following steps: Step (1): Punch holes in the bending area of the glass; Step (2): Chemically etch the glass processed in Step (1); Step (3): Temper the glass processed in Step (2); Step (4): Surface-etch the glass processed in Step (3). In Step (1), a picosecond laser cutting machine is used to cut and punch holes in the bending area of the glass.

[0005] This preparation method uses an infrared laser to punch holes and cut the bending area of the glass. However, since soda-lime glass is more sensitive to lasers than quartz glass and the like, during the laser cutting process, situations such as chipping and laser ablation may occur.

[0006] Therefore, the technical problem to be solved by the present invention is: how to improve the cutting yield rate of the foldable soda-lime glass. Summary of the Invention

[0007] The main object of the present invention is to provide a preparation method of a foldable glass. By using a picosecond solid-state laser to cut soda-lime glass, it is possible to avoid the generation of high temperature on the glass due to overly concentrated laser energy, thereby preventing the soda-lime glass from cracking or chipping. Secondly, by setting the parameters of the solid-state laser, the distribution of the same output light energy per unit time can be controlled, reducing the chipping situation of the soda-lime glass and improving the yield rate of the soda-lime glass.

[0008] Meanwhile, the present invention also provides a foldable glass.

[0009] To achieve the above object, the technical solution adopted by the present application is as follows:

[0010] A method for preparing a foldable glass, comprising the following steps:

[0011] Step 1: Use a picosecond solid-state laser to punch and cut the bending position of soda-lime glass.

[0012] Step 2: After cutting, immerse the soda-lime glass in an acidic solution for corrosion and use ultrasonic vibration to make the waste materials in the cutting area fall off, obtaining the target glass.

[0013] Preferably, during the punching and cutting process, the laser power of the picosecond solid-state laser is 12 - 15 W, the pulse width is 1 - 3 ps, and the number of pulses is 5 - 7.

[0014] 1. Soda-lime glass has good chemical stability, weak strength, good optical properties, a relatively high coefficient of thermal expansion, and strong light absorption and reflection capabilities; quartz glass has high temperature resistance, good light transmittance, especially high transmittance in the ultraviolet and infrared ranges, and a low coefficient of thermal expansion; borosilicate glass has high temperature resistance, relatively high strength, and a low coefficient of thermal expansion.

[0015] 2. We found that when using the methods of the prior art and using carbon dioxide lasers, solid lasers, and femtosecond lasers to process quartz glass or borosilicate glass, generally there will be no obvious chipping problems. However, when processing soda-lime glass, especially thin soda-lime glass, problems such as discoloration, chipping, cracks, and hole waists will occur. The reasons for these problems are as follows: Since soda-lime glass is sensitive to the energy of the laser, too high energy will cause ablation and discoloration at the laser cutting position; the strength of soda-lime glass is weak, especially for soda-lime glass with a micron-level thickness, and its rigidity is low, and chipping and cracking will occur under femtosecond laser irradiation; due to the relatively high density of soda-lime glass, strong light absorption and reflection, if the laser energy is too small or the parameter matching is not good, the energy reaching the center of the soda-lime glass cannot complete the modification of the glass, resulting in the situation of hole waists after corrosion.

[0016] Based on this, through the screening of different lasers and parameters, the present invention finds that under the conditions of using a solid-state laser with a laser power of 12 - 15 W, a pulse width of 1 - 3 ps, and a number of pulses of 5 - 7, soda-lime glass can just right not have obvious problems such as discoloration, chipping, cracks, and waists.

[0017] In some embodiments of the present invention, the laser power is preferably 12W, 13W, 14W, 15W; the pulse width is preferably 1ps, 2ps, 3ps; the number of pulses is preferably 5, 6, 7.

[0018] Preferably, in step 1, during the punching and cutting process, the light output spacing of the picosecond pulsed solid-state laser is 3 - 7μm, the laser focal depth is 0.6 - 1mm, the cutting speed is 15 - 25mm / s, and the cutting acceleration is 10 - 20mm / s 2 。

[0019] In some embodiments of the present invention, the light output spacing of the picosecond pulsed solid-state laser is preferably 3μm, 4μm, 5μm, 6μm, 7μm, the laser focal depth is preferably 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, the cutting speed is preferably 15mm / s, 17mm / s, 19mm / s, 21mm / s, 23mm / s, 25mm / s, and the cutting acceleration is preferably 10mm / s 2 、12mm / s 2 、14mm / s 2 、16mm / s 2 、18mm / s 2 、20mm / s 2 。

[0020] Preferably, in step 1, the thickness of the soda-lime glass is 100 - 140μm; the cutting width of the punching and cutting is 90 - 110μm, and the length is 3800 - 4000μm.

[0021] In some embodiments of the present invention, the thickness of the soda-lime glass is preferably 100μm, 110μm, 120μm, 130μm, 140μm; the cutting width of the punching and cutting is preferably 90μm, 95μm, 100μm, 105μm, 110μm, and the length is preferably 3800μm, 3850μm, 3900μm, 3950μm, 4000μm.

[0022] Preferably, in step 2, the acidic solution is an aqueous hydrofluoric acid solution with a mass fraction of hydrofluoric acid of 3 - 7%; the etching time is 16 - 20min; the frequency of the ultrasonic vibration is 15 - 25kHz.

[0023] In some embodiments of the present invention, the acidic solution is an aqueous hydrofluoric acid solution with a mass fraction of hydrofluoric acid of 3%, 4%, 5%, 6%, 7%; the etching time is preferably 16min, 17min, 18min, 19min, 20min; the frequency of the ultrasonic vibration is preferably 15kHz, 17kHz, 19kHz, 21kHz, 23kHz, 25kHz.

[0024] Preferably, in the soda-lime glass, the mass fraction of SiO 2 is 60-75%; the mass fraction of Na 2 2O is 10-25%; the mass fraction of CaO is 5-15%.

[0025] In some embodiments of the present invention, the mass fraction of SiO 2 is preferably 60%, 65%, 70%, 75%; the mass fraction of Na 2 2O is preferably 10%, 15%, 20%, 25%; the mass fraction of CaO is preferably 5%, 7%, 9%, 11%, 13%, 15%.

[0026] Preferably, it further includes step 3: successively cleaning the target glass with alcohol and pure water for 3-7 minutes and then drying it.

[0027] In some embodiments of the present invention, the target glass is successively cleaned with alcohol and pure water for 3 minutes, 4 minutes, 5 minutes, 6 minutes, 7 minutes.

[0028] Preferably, the drying temperature is 170-230 °C; the drying time is 6-10 minutes.

[0029] In some embodiments of the present invention, the drying temperature is preferably 170 °C, 180 °C, 190 °C, 200 °C, 210 °C, 220 °C, 230 °C; the drying time is preferably 6 minutes, 7 minutes, 8 minutes, 9 minutes, 10 minutes.

[0030] Preferably, before performing step 1, a picosecond solid-state laser is used to cut the shape of the soda-lime glass; during the cutting process, the light output spacing is preferably 6-10 μm.

[0031] In some embodiments of the present invention, during the cutting process, the light output spacing is 6 μm, 7 μm, 8 μm, 9 μm, 10 μm.

[0032] Meanwhile, a foldable glass is also provided, which is prepared by the above preparation method.

[0033] Compared with the prior art, the present solution has the following beneficial effects:

[0034] The preparation method of the present invention. Compared with other infrared lasers, the solid-state laser has stable performance and high beam quality. By using a picosecond solid-state laser to cut soda-lime glass, the soda-lime glass can be stably cut, avoiding ablation and discoloration of the soda-lime glass caused by unstable output or excessive energy. Secondly, by adjusting the parameters of the picosecond solid-state laser, the distribution of the output light energy per unit time can be controlled, avoiding cracks or chipping on the soda-lime glass due to overly concentrated laser energy during the cutting process. Moreover, this method can reduce the length of the chipping of the soda-lime glass to less than 3 μm and maintain the transmittance of the processed area of the soda-lime glass above 95%. Detailed implementation mode

[0035] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are some, rather than all, of the embodiments of the present application. Usually, the components of the present application shown here can be arranged and designed in various different configurations.

[0036] Embodiment 1

[0037] A preparation method of foldable glass includes the following steps:

[0038] Step 1: Use a picosecond solid-state laser to cut the shape of the soda-lime glass; during the process of cutting the outer contour of the soda-lime glass, the light output spacing of the laser is set to 8 μm, the laser power is set to 15 W, the pulse width is set to 1 ps, the number of pulses is set to 6, the cutting speed is 20 mm / s, and the cutting acceleration is 15 mm / s 2 , the laser focal depth is 0.8 mm, and the laser focal length is controlled at the middle position of the backplane glass, that is, at a depth of 60 μm of the glass. Cut the outer contour shape of the soda-lime glass according to the processing drawing, and the machining allowance is 4 mm; the mass fraction of SiO 2 in the soda-lime glass is 75%, and the mass fraction of Na 2 O is 13%, and the mass fraction of CaO is 12%. The thickness of the soda-lime glass is 120 μm;

[0039] Step 2: Use a picosecond solid-state laser to punch and cut the bending position of the soda-lime glass; during the punching and cutting process, the light output spacing of the laser is set to 5 μm, and the other parameters are the same as those of the laser in Step 1. Punch and cut at the middle position of the soda-lime glass to cut out strip-shaped holes with a width of 100 μm and a length of 3900 μm. The number of strip-shaped holes is 412, and each strip-shaped hole is arranged in an array and staggered at the bending position;

[0040] Step 3: After cutting is completed, the laser causes the glass at the cutting position of the soda-lime glass to denature. The waste material in the strip-shaped holes does not detach. The soda-lime glass needs to be immersed in hydrofluoric acid with a concentration of 5% for 18 minutes, and at the same time, ultrasonic waves with a frequency of 20 kHz are used to vibrate the soda-lime glass. The deformed glass reacts more easily with hydrofluoric acid, so that the waste material detaches to obtain the target glass;

[0041] Step 4: After the waste material in the soda-lime glass falls off, first clean the target glass with alcohol for 5 minutes, and then clean the target glass with pure water for 5 minutes. After cleaning is completed, dry the target glass. The drying temperature is 200 °C and the drying time is 8 minutes to make the surface of the soda-lime glass free of water marks.

[0042] Example 2

[0043] This example is basically the same as Example 1, except that: during the punching and cutting process, the laser power of the picosecond solid-state laser is 12 W, the pulse width is 3 ps, and the number of pulses is 5.

[0044] Example 3

[0045] This example is basically the same as Example 1, except that: during the punching and cutting process, the laser power of the picosecond solid-state laser is 13 W, the pulse width is 2 ps, and the number of pulses is 7.

[0046] Example 4

[0047] This comparative example is basically the same as Example 1, except that: during the punching and cutting process, the laser power of the picosecond solid-state laser is 10 W.

[0048] Example 5

[0049] This comparative example is basically the same as Example 1, except that: during the punching and cutting process, the laser power of the picosecond solid-state laser is 20 W.

[0050] Example 6

[0051] This comparative example is basically the same as Example 1, except that: during the punching and cutting process, the pulse width of the picosecond solid-state laser is 5 ps.

[0052] Example 7

[0053] This comparative example is basically the same as Example 1, except that: during the punching and cutting process, the number of pulses of the picosecond solid-state laser is 3.

[0054] Example 8

[0055] This comparative example is basically the same as Example 1, except that: during the punching and cutting process, the number of pulses of the picosecond solid-state laser is 8.

[0056] Comparative Example 1

[0057] This comparative example is basically the same as Example 1, except that: a picosecond carbon dioxide laser is used to cut the shape of soda-lime glass.

[0058] Comparative Example 2

[0059] This comparative example is basically the same as Example 1, except that: a picosecond solid-state laser is used to cut the shape of fused quartz glass; the laser power of the picosecond solid-state laser is set to 20 W, and the other parameters are the same as those in Example 1.

[0060] Comparative Example 3

[0061] This comparative example is basically the same as Example 1, except that: a picosecond solid-state laser is used to cut the shape of borosilicate glass; the laser power of the picosecond solid-state laser is set to 20 W, and the other parameters are the same as those in Example 1.

[0062] Comparative Example 4

[0063] This comparative example is basically the same as Example 1, except that: Step 1: A femtosecond laser is used to cut the shape of soda-lime glass; during the cutting of the shape of soda-lime glass, the parameters of the femtosecond laser are set as follows: laser output energy 60%, pulse width 900 fs, pulse repetition frequency 200 kHz, and number of pulses 1;

[0064] Step 2: A femtosecond laser is used to punch and cut the bending position of soda-lime glass; during the punching and cutting process, the parameters of the femtosecond laser are the same as those of the femtosecond laser in Step 1. Punching and cutting are carried out at the middle position of soda-lime glass to cut out strip-shaped holes with a width of 100 μm and a length of 3900 μm, and the number of strip-shaped holes is 412. Each strip-shaped hole is arranged in an array and staggered on the bending position;

[0065] Step 3: After cutting is completed, the laser makes the glass at the cutting position of soda-lime glass denature, and the waste materials in the strip-shaped holes do not fall off. It is necessary to immerse the soda-lime glass in hydrofluoric acid with a concentration of 5% for 18 min, and at the same time, use ultrasonic waves with a frequency of 20 kHz to vibrate the soda-lime glass. The deformed glass reacts more easily with hydrofluoric acid, so that the waste materials fall off to obtain the target glass;

[0066] Step 4: After the waste materials in soda-lime glass fall off, first use alcohol to clean the target glass for 5 min, then use pure water to clean the target glass for 5 min. After cleaning is completed, dry the target glass. The drying temperature is 200 °C and the drying time is 8 min to make the surface of the soda-lime glass free of water marks.

[0067] Using the methods of Examples 1 to 8 and Comparative Examples 1 to 4 respectively, 100 soda-lime glasses were prepared. The cutting positions of the soda-lime glasses were observed using a Keyence 3D microscope to detect the chipping conditions of the soda-lime glasses. When the length of the chipping was less than 3 μm, the soda-lime glass was a good product. By dividing the number of good products by the total number, the yield rate of the soda-lime glass was obtained.

[0068] The results are shown in Table 1:

[0069] Test results of soda-lime glass

[0070]

[0071]

[0072] Result analysis:

[0073] As can be seen from Examples 1 to 3, for soda-lime glass under picosecond solid-state laser with specific parameters, the yield rate is between 88% and 100%. A good yield rate can be obtained within this parameter range. Secondly, using the parameters in Example 1, there is basically no chipping phenomenon in the soda-lime glass, which can greatly improve the cutting yield rate of the soda-lime glass.

[0074] As can be seen from Example 1 and Examples 4 and 5, when the laser power is too small, the laser cannot cut the soda-lime glass, resulting in the waste at the cutting position of the soda-lime glass not being able to break away, thus unable to achieve the cutting of the soda-lime glass; while when the laser power is too large, due to the increase in the output light energy of the laser, during the laser cutting process, the soda-lime glass will have ablation phenomenon, resulting in the discoloration and chipping of the soda-lime glass, causing poor processing of the soda-lime glass.

[0075] As can be seen from Example 1 and Example 6, when the pulse width of the laser is set too high, it will increase the difficulty of laser cutting, make the quality of laser cutting worse, and thus lead to more chipping at the cutting position of the soda-lime glass.

[0076] As can be seen from Example 1 and Examples 7 and 8, when the number of pulses is too high or too low, it will affect the hole-forming quality after laser cutting, resulting in the shape of the holes formed in the soda-lime glass after laser cutting. Moreover, the setting of the number of pulses will also affect the shape of the holes in the glass thickness direction, showing a waist phenomenon, thus causing poor cutting of the soda-lime glass. Secondly, the number of pulses also affects the chipping situation during laser cutting to a certain extent.

[0077] As can be seen from Example 1 and Comparative Example 1, when using a carbon dioxide laser to cut the soda-lime glass, the yield rate is only 4%. The reason is that: the output light of the carbon dioxide laser is unstable, and the quality of the light beam is not very good. When applied to the precision cutting of soda-lime glass, the cutting quality is poor.

[0078] As can be seen from Example 1 and Comparative Examples 2 and 3, when a picosecond solid-state laser is used to cut fused silica glass and borosilicate glass, the yield of cutting is relatively low. The reason is that: the strength of fused silica glass and borosilicate glass is relatively high. When a picosecond laser is used for cutting, the modification effect of the laser on the fused silica glass and borosilicate glass during cutting is poor, and the difficulty of the subsequent etching process will increase accordingly. The situation where the chipping is greater than 3 microns will increase. After increasing the laser power, the yield of fused silica glass and borosilicate glass is still relatively low. In precision machining, fused silica glass and borosilicate glass generally need to be cut using a femtosecond laser.

[0079] As can be seen from Example 1 and Comparative Example 4, when a femtosecond solid-state laser is used to cut soda-lime glass, since the soda-lime glass is relatively brittle, chipping is likely to occur during laser cutting. When a femtosecond laser is used for cutting, because the output energy of the femtosecond laser is more concentrated, during the cutting process of soda-lime glass, chipping is likely to occur due to the overly concentrated energy, resulting in poor chipping.

[0080] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that: various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the claims and their equivalents.

Claims

1. A method for preparing foldable glass, characterized in that: The following steps are involved: Step 1: Use a picosecond solid-state laser to punch and cut the bending position of the soda-lime glass; Step 2: After the cutting is completed, the soda lime glass is immersed in an acid solution for etching and ultrasonic vibration is used to make the waste in the cutting area fall off to obtain the target glass.

2. The method for preparing foldable glass according to claim 1, characterized in that: In step 1, during the punching and cutting process, the laser power of the picosecond solid-state laser is 12-15 W, the pulse width is 1-3 ps, and the number of pulses is 5-7.

3. The method for preparing foldable glass according to claim 1, characterized in that: In step 1, during the punching and cutting process, the light emission spacing of the picosecond solid laser is 3-7 μm, the laser focal depth is 0.6-1 mm, the cutting speed is 15-25 mm / s, and the cutting acceleration is 10-20 mm / s. 2 .

4. The method for preparing foldable glass according to claim 1, characterized in that: In the step 1, the thickness of the soda-lime glass is 100-140 μm; the cutting width of the punching cutting is 90-110 μm, and the length is 3800-4000 μm.

5. The method for preparing foldable glass according to claim 1, characterized in that: In step 2, the acidic solution is a hydrofluoric acid aqueous solution with a mass fraction of 3-7% of hydrofluoric acid; the corrosion time is 16-20 minutes; and the frequency of the ultrasonic vibration is 15-25 kHz.

6. The method for preparing foldable glass according to claim 1, characterized in that: In the soda-lime glass, the mass fraction of SiO2 is 60-75%; the mass fraction of Na2O is 10-25%; and the mass fraction of CaO is 5-15%.

7. The method for preparing foldable glass according to claim 1, characterized in that: The method also includes step 3: using alcohol and pure water to clean the target glass in turn for 3 to 7 minutes and then drying it.

8. The method for preparing foldable glass according to claim 7, characterized in that: The drying temperature is 170-230°C; the drying time is 6-10 minutes.

9. The method for preparing foldable glass according to claim 1, characterized in that: Before performing step 1, a picosecond solid-state laser is used to cut the shape of the soda-lime glass; during the cutting process, the light output spacing is 6 to 10 μm.

10. A foldable glass, characterized in that: The method is prepared by any one of claims 1 to 9.

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