High-precision ultra-smooth optical glass and preparation method thereof

Abstract

Disclosed are high-precision ultra-smooth optical glass and a preparation method thereof, belonging to the technical field of glass manufacturing. The preparation method of the high-precision ultra-smooth optical glass comprises three steps: melting, forming, and polishing. The high-precision ultra-smooth optical glass prepared by the present invention has a light transmittance of 93-94%, a refractive index of 1.92-1.96, an Abbe number of 40-43, and a surface roughness of 0.211-0.232 nm.

Description

Technical Field

[0001] The invention relates to high-precision ultra-smooth optical glass and a preparation method thereof, belonging to the technical field of glass manufacturing. Background Art

[0002] High-precision optical glass features a high refractive index, high transmittance, high smoothness, and low dispersion coefficient. These performance characteristics align with the trend toward miniaturization of optical components and play a crucial role in simplifying optical systems. With the advancement of technology, ordinary optical glass with a refractive index between 1.5 and 1.7 is no longer able to meet the demanding requirements of optical devices. High-precision optical glass with a refractive index of 1.9 or higher has become the development direction of high-performance optical glass.

[0003] Chinese patent CN119038876A discloses a method for preparing low-stress, high-precision optical glass, including the following steps: S1. Raw material preparation; S2. Raw material mixing: placing the prepared glass raw materials into a mixing device, first adding phosphorus pentoxide, then zirconium oxide, and finally titanium dioxide or nano-silicon powder; S3. Melting; S4. Forming and annealing; S5. Polishing; S6. Surface cleaning; S7. Coating. The low-stress, high-precision optical glass obtained in this patent has a transmittance of only 85%, a maximum refractive index of only 1.6, and poor smoothness, failing to meet the requirements of high-precision optical glass.

[0004] Chinese patent CN118324408A discloses a high-precision, ultra-smooth optical glass characterized by its composition, in molar percentage, comprising: SiO2: 24-36%; Nb2O5: 18-38%; ZrO2: 0.5-10%; RO: 7-30%; Na2O: 3-16%; Al2O3: 1-5%; and B2O3: 2-8%. The RO / Nb2O5 ratio is 0.2-1.5, with RO being the combined content of MgO, CaO, SrO, and BaO. The optical glass has a refractive index of 1.70-1.74 and an Abbe number of 32-37. The high-precision, ultra-smooth optical glass obtained in this patent has a maximum refractive index of 1.74, but also a low Abbe number and severe dispersion, making it less than ideal for high-precision optical glass.

[0005] From the above, it can be seen that the current high-precision ultra-smooth optical glass still has prominent problems such as low refractive index, high dispersion coefficient, and poor smoothness. Therefore, the preparation of high-precision ultra-smooth optical glass with high refractive index, low dispersion and high smoothness has very important practical significance. Summary of the Invention

[0006] In view of the above-mentioned deficiencies in the prior art, the present invention provides a high-precision ultra-smooth optical glass and a preparation method thereof, to achieve the following invention objectives: to prepare high-precision ultra-smooth optical glass with high refractive index, low dispersion and high smoothness.

[0007] In order to achieve the above-mentioned object of the invention, the present invention adopts the following technical solutions:

[0008] A high-precision ultra-smooth optical glass and a preparation method thereof. The raw material composition of the high-precision ultra-smooth optical glass is, in parts by weight:

[0009] 60~100 parts of silicon dioxide,

[0010] 25~70 parts of aluminum oxide,

[0011] 15-50 parts of sodium oxide,

[0012] 10-25 parts of magnesium oxide,

[0013] 10~40 parts of calcium oxide,

[0014] 5-25 parts of lithium oxide,

[0015] 5~9 parts of flux,

[0016] 3~10 parts of compound clarifier,

[0017] 5-13 parts of high light transmittance and high refractive index additives;

[0018] The flux is sodium tetraborate;

[0019] The composite clarifier is a mixture of cerium dioxide and aluminum borate;

[0020] The mass ratio of cerium dioxide to aluminum borate is 10-57:100;

[0021] The high-transmittance and high-refractive additive is a mixture of lanthanum disilicide and samarium disilicide;

[0022] The mass ratio of the lanthanum disilicide and samarium disilicide is 25-80:13;

[0023] The following are further improvements to the above technical solution:

[0024] Step 1: Melting

[0025] According to the raw material composition of high-precision ultra-smooth optical glass in parts by weight, silicon dioxide, aluminum oxide, sodium oxide, magnesium oxide, calcium oxide, lithium oxide, flux, compound clarifier, and high-transmittance and high-refractive additive are preliminarily mixed evenly, placed in a glass melting furnace, and melted into a high-temperature glass melt after a heating and constant temperature process;

[0026] The specific operation of the heating and constant temperature process is as follows: heating to 1000-1200°C at a rate of 2-5°C / min and keeping warm for 30-50 minutes, then heating to 1500-1680°C at a rate of 1-3°C / min and keeping warm for 1-4 hours, and then cooling to 1400-1480°C and keeping warm for 20-40 minutes.

[0027] Step 2: Molding

[0028] The high-temperature molten glass is led from the glass furnace to the casting port through the material channel and continuously cast on the mold to obtain a glass sheet. The glass sheet is then annealed and cooled to obtain a high-precision ultra-smooth optical glass semi-finished product;

[0029] The casting is carried out on a mold, and the temperature of the mold needs to be kept constant at 600-700°C in advance;

[0030] The annealing temperature is 550-600° C. and the annealing time is 1-2 hours;

[0031] The cooling process has a cooling rate of 3-6°C / min.

[0032] Step 3: Polishing

[0033] Use a single-axis grinding and polishing machine and a polyurethane polishing pad to perform chemical mechanical polishing on high-precision ultra-smooth optical glass semi-finished products. Control the spindle speed, swing frame speed, polishing liquid droplet acceleration and polishing time. After polishing, wash with deionized water and dry with clean compressed air to obtain high-precision ultra-smooth optical glass products.

[0034] The polishing liquid is specifically composed of, in parts by weight: 35-65 parts of cerium oxide abrasive, 10-25 parts of tributyl phosphate, 5-15 parts of composite surfactant, 3-8 parts of mixed acid, and 50-80 parts of deionized water;

[0035] The composite surfactant is a mixture of fatty alcohol polyoxyethylene ether sodium sulfate and isooctyl alcohol polyoxyethylene ether JFC-2;

[0036] The mass ratio of the fatty alcohol polyoxyethylene ether sodium sulfate and isooctyl alcohol polyoxyethylene ether JFC-2 is 30-90:17;

[0037] The mixed acid is a mixture of mellitic acid and phosphoric acid, with a mass ratio of the two being 10-47:30;

[0038] The particle size of the cerium oxide abrasive is 50-400 nm;

[0039] The spindle speed is 60-90 rpm;

[0040] The swing frame rotates at a speed of 25 to 40 rpm;

[0041] The polishing liquid droplet acceleration is 0.5~1mL / min;

[0042] The polishing time is 3 to 4.5 hours.

[0043] Compared with the prior art, the present invention achieves the following beneficial effects:

[0044] 1. The present invention uses a clarifier compounded with cerium dioxide and aluminum borate. Cerium dioxide is a commonly used high-efficiency glass clarifier and is also very suitable for optical glass, improving the refractive index and light transmittance of optical glass. Aluminum borate combined with ceria can particularly effectively improve the clarification effect of glass melts at high temperatures. Aluminum borate has a high decomposition temperature, and the gas generated during decomposition can vigorously stir the glass melt, promoting the coalescence and discharge of tiny bubbles. In addition, the boric acid and aluminum oxide components of the decomposed aluminum borate, which are not promptly discharged from the glass melt at the high temperature stage, can also become components of the optical glass. Moreover, there is no negative impact on the refractive index, light transmittance, and Abbe number of the optical glass.

[0045] 2. The high-transmittance and high-refractive additive added in the present invention, namely a mixture of lanthanum disilicide and samarium disilicide, has relatively low melting points and can be fully melted during the glass melting process. More importantly, the lanthanum ions and samarium ions produced by the melting of these two substances will enter the network structure of the glass melt under the guidance of silicon anions, reducing the oxygen packing density and crystallization ability of the glass, thereby increasing the composition content of the amorphous glass network, and ultimately improving the refractive index and transmittance of the optical glass, increasing the Abbe number, and reducing the degree of dispersion;

[0046] 3. A mixed acid composed of mellitic acid and phosphoric acid is added to the polishing liquid used in the present invention. The main function of the mixed acid is to adjust and maintain the pH value of the polishing liquid at a moderate acidity to prevent excessive precipitation and particle agglomeration of cerium dioxide polishing powder in a non-acidic environment, which leads to a rapid increase in polishing particles and a sharp decline in polishing effect. The main function of mellitic acid is to complex the finer cerium dioxide particles formed during the polishing process and prevent the agglomeration of fine particles. Phosphoric acid, mainly due to its tribasic acid properties, can undergo multi-step ionization during the polishing process to form a large number of ionized acid products, thereby maintaining and buffering the pH fluctuation of the polishing liquid, so that the pH value of the polishing liquid fluctuates within a relatively small range, thereby avoiding excessive agglomeration of particle components in the polishing liquid and instability of the chemical polishing environment components on the glass surface.

[0047] 4. The composite surfactant added to the polishing liquid of the present invention, namely, sodium fatty alcohol polyoxyethylene ether sulfate and isooctyl alcohol polyoxyethylene ether JFC-2, has dispersing, emulsifying, penetrating, solubilizing, and wetting properties. While promoting good dispersion of particulate matter within the system, more importantly, sodium fatty alcohol polyoxyethylene ether sulfate and isooctyl alcohol polyoxyethylene ether JFC-2 can cooperate with mellitic acid to adsorb on the surface of the particles, making the particle surface negatively charged. The electrostatic repulsive force prevents the agglomeration of adjacent particles. In addition, the long organic molecular chains of sodium fatty alcohol polyoxyethylene ether sulfate and isooctyl alcohol polyoxyethylene ether JFC-2 act as steric hindrance at the outer ends, further preventing particle agglomeration.

[0048] 5. The high-precision ultra-smooth optical glass prepared by the present invention has a light transmittance of 93-94%, a refractive index of 1.92-1.96, an Abbe number of 40-43, and a surface roughness of 0.211-0.232 nm. DETAILED DESCRIPTION

[0049] The preferred embodiments of the present invention are described below. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0050] Example 1: A method for preparing high-precision ultra-smooth optical glass

[0051] Step 1: Melting

[0052] The raw material composition of the high-precision ultra-smooth optical glass is, in parts by weight:

[0053] 90 parts of silicon dioxide,

[0054] 60 parts of aluminum oxide,

[0055] 45 parts of sodium oxide,

[0056] 15 parts of magnesium oxide,

[0057] 30 parts of calcium oxide,

[0058] 20 parts of lithium oxide,

[0059] 8 parts of flux,

[0060] 9 parts of compound clarifier,

[0061] 11 parts of high light transmittance and high refractive index additives;

[0062] The flux is sodium tetraborate;

[0063] The compound clarifier is a mixture of cerium dioxide and aluminum borate;

[0064] The mass ratio of the cerium dioxide to the aluminum borate is 33:100;

[0065] The high-transmittance and high-refractive additive is a mixture of lanthanum disilicide and samarium disilicide;

[0066] The mass ratio of the lanthanum disilicide and samarium disilicide is 45:13;

[0067] According to the raw material composition of high-precision ultra-smooth optical glass in parts by weight, silicon dioxide, aluminum oxide, sodium oxide, magnesium oxide, calcium oxide, lithium oxide, flux, compound clarifier, and high-transmittance and high-refractive additive are preliminarily mixed evenly, placed in a glass melting furnace, and melted into a high-temperature glass melt after a heating and constant temperature process;

[0068] The specific operation of the heating and constant temperature process is: heating to 1100°C at a rate of 3°C / min and keeping it warm for 45 minutes, then heating to 1580°C at a rate of 2°C / min and keeping it warm for 3 hours, and then cooling to 1460°C and keeping it warm for 20-40 minutes.

[0069] Step 2: Molding

[0070] The high-temperature molten glass is led from the glass furnace to the casting port through the material channel and continuously cast on the mold to obtain a glass sheet. The glass sheet is then annealed and cooled to obtain a high-precision ultra-smooth optical glass semi-finished product;

[0071] The casting is carried out on a mold, and the temperature of the mold needs to be kept constant at 660°C in advance;

[0072] The annealing temperature is 580°C and the annealing time is 1.6 hours;

[0073] The cooling rate is 4°C / min.

[0074] Step 3: Polishing

[0075] Use a single-axis grinding and polishing machine and a polyurethane polishing pad to perform chemical mechanical polishing on high-precision ultra-smooth optical glass semi-finished products. Control the spindle speed, swing frame speed, polishing liquid droplet acceleration and polishing time. After polishing, wash with deionized water and dry with clean compressed air to obtain high-precision ultra-smooth optical glass products.

[0076] The polishing liquid is specifically composed of, by weight: 55 parts of cerium oxide abrasive, 20 parts of tributyl phosphate, 10 parts of composite surfactant, 6 parts of mixed acid, and 70 parts of deionized water;

[0077] The composite surfactant is a mixture of fatty alcohol polyoxyethylene ether sodium sulfate and isooctyl alcohol polyoxyethylene ether JFC-2;

[0078] The mass ratio of the fatty alcohol polyoxyethylene ether sodium sulfate and isooctyl alcohol polyoxyethylene ether JFC-2 is 80:17;

[0079] The mixed acid is a mixture of mellitic acid and phosphoric acid, with a mass ratio of 37:30;

[0080] The particle size of the cerium oxide abrasive is 100 nm;

[0081] The spindle speed is 80 rpm;

[0082] The swing frame has a rotation speed of 30 rpm;

[0083] The polishing liquid droplet acceleration is 0.8 mL / min;

[0084] The polishing time is 4 hours.

[0085] Example 2: A method for preparing high-precision ultra-smooth optical glass

[0086] Step 1: Melting

[0087] The raw material composition of the high-precision ultra-smooth optical glass is, in parts by weight:

[0088] 60 parts of silicon dioxide,

[0089] 25 parts of aluminum oxide,

[0090] 15 parts of sodium oxide,

[0091] 10 parts of magnesium oxide,

[0092] 10 parts calcium oxide,

[0093] 5 parts of lithium oxide,

[0094] 5 parts of flux,

[0095] 3 parts of compound clarifier,

[0096] 5 parts of high light transmittance and high refractive index additive;

[0097] The flux is sodium tetraborate;

[0098] The compound clarifier is a mixture of cerium dioxide and aluminum borate;

[0099] The mass ratio of the cerium dioxide to the aluminum borate is 10:100;

[0100] The high-transmittance and high-refractive additive is a mixture of lanthanum disilicide and samarium disilicide;

[0101] The mass ratio of the lanthanum disilicide and samarium disilicide is 25:13;

[0102] According to the raw material composition of high-precision ultra-smooth optical glass in parts by weight, silicon dioxide, aluminum oxide, sodium oxide, magnesium oxide, calcium oxide, lithium oxide, flux, compound clarifier, and high-transmittance and high-refractive additive are preliminarily mixed evenly, placed in a glass melting furnace, and melted into a high-temperature glass melt after a heating and constant temperature process;

[0103] The specific operation of the temperature rising and constant temperature process is: heating to 1000°C at a rate of 2°C / min and keeping warm for 30 minutes, then heating to 1500°C at a rate of 1°C / min and keeping warm for 1 hour, and then cooling to 1400°C and keeping warm for 20 minutes.

[0104] Step 2: Molding

[0105] The high-temperature molten glass is led from the glass furnace to the casting port through the material channel and continuously cast on the mold to obtain a glass sheet. The glass sheet is then annealed and cooled to obtain a high-precision ultra-smooth optical glass semi-finished product;

[0106] The casting is carried out on a mold, and the temperature of the mold needs to be kept constant at 600°C in advance;

[0107] The annealing temperature is 550° C. and the annealing time is 1 hour;

[0108] The cooling rate is 3°C / min.

[0109] Step 3: Polishing

[0110] Use a single-axis grinding and polishing machine and a polyurethane polishing pad to perform chemical mechanical polishing on high-precision ultra-smooth optical glass semi-finished products. Control the spindle speed, swing frame speed, polishing liquid droplet acceleration and polishing time. After polishing, wash with deionized water and dry with clean compressed air to obtain high-precision ultra-smooth optical glass products.

[0111] The polishing liquid is specifically composed of, by weight: 35 parts of cerium oxide abrasive, 10 parts of tributyl phosphate, 5 parts of composite surfactant, 3 parts of mixed acid, and 50 parts of deionized water;

[0112] The composite surfactant is a mixture of fatty alcohol polyoxyethylene ether sodium sulfate and isooctyl alcohol polyoxyethylene ether JFC-2;

[0113] The mass ratio of the fatty alcohol polyoxyethylene ether sodium sulfate and isooctyl alcohol polyoxyethylene ether JFC-2 is 30:17;

[0114] The mixed acid is a mixture of mellitic acid and phosphoric acid, with a mass ratio of 10:30;

[0115] The particle size of the cerium oxide abrasive is 50 nm;

[0116] The spindle speed is 60 rpm;

[0117] The swing frame has a rotation speed of 25 rpm;

[0118] The polishing liquid droplet acceleration is 0.5 mL / min;

[0119] The polishing time is 3 hours.

[0120] Example 3: A method for preparing high-precision ultra-smooth optical glass

[0121] Step 1: Melting

[0122] The raw material composition of the high-precision ultra-smooth optical glass is, in parts by weight:

[0123] 100 parts of silicon dioxide,

[0124] 70 parts of aluminum oxide,

[0125] 50 parts of sodium oxide,

[0126] 25 parts of magnesium oxide,

[0127] 40 parts of calcium oxide,

[0128] 25 parts of lithium oxide,

[0129] 9 parts of flux,

[0130] 10 parts of compound clarifier,

[0131] 13 parts of high light transmittance and high refractive index additives;

[0132] The flux is sodium tetraborate;

[0133] The composite clarifier is a mixture of cerium dioxide and aluminum borate;

[0134] The mass ratio of cerium dioxide to aluminum borate is 57:100;

[0135] The high-transmittance and high-refractive additive is a mixture of lanthanum disilicide and samarium disilicide;

[0136] The mass ratio of the lanthanum disilicide and samarium disilicide is 80:13;

[0137] According to the raw material composition of high-precision ultra-smooth optical glass in parts by weight, silicon dioxide, aluminum oxide, sodium oxide, magnesium oxide, calcium oxide, lithium oxide, flux, compound clarifier, and high-transmittance and high-refractive additive are preliminarily mixed evenly, placed in a glass melting furnace, and melted into a high-temperature glass melt after a heating and constant temperature process;

[0138] The specific operation of the heating and constant temperature process is: heating to 1200°C at a rate of 5°C / min and keeping it warm for 50 minutes, then heating to 1680°C at a rate of 3°C / min and keeping it warm for 4 hours, and then cooling to 1480°C and keeping it warm for 40 minutes.

[0139] Step 2: Molding

[0140] The high-temperature molten glass is led from the glass furnace to the casting port through the material channel and continuously cast on the mold to obtain a glass sheet. The glass sheet is then annealed and cooled to obtain a high-precision ultra-smooth optical glass semi-finished product;

[0141] The casting is carried out on a mold, and the temperature of the mold needs to be kept constant at 700°C in advance;

[0142] The annealing temperature is 600° C. and the annealing time is 2 hours;

[0143] The cooling rate is 6°C / min.

[0144] Step 3: Polishing

[0145] Use a single-axis grinding and polishing machine and a polyurethane polishing pad to perform chemical mechanical polishing on high-precision ultra-smooth optical glass semi-finished products. Control the spindle speed, swing frame speed, polishing liquid droplet acceleration and polishing time. After polishing, wash with deionized water and dry with clean compressed air to obtain high-precision ultra-smooth optical glass products.

[0146] The polishing liquid is specifically composed of, by weight: 65 parts of cerium oxide abrasive, 25 parts of tributyl phosphate, 15 parts of composite surfactant, 8 parts of mixed acid, and 80 parts of deionized water;

[0147] The composite surfactant is a mixture of fatty alcohol polyoxyethylene ether sodium sulfate and isooctyl alcohol polyoxyethylene ether JFC-2;

[0148] The mass ratio of the fatty alcohol polyoxyethylene ether sodium sulfate and isooctyl alcohol polyoxyethylene ether JFC-2 is 90:17;

[0149] The mixed acid is a mixture of mellitic acid and phosphoric acid, with a mass ratio of 47:30;

[0150] The particle size of the cerium oxide abrasive is 400 nm;

[0151] The spindle speed is 90 rpm;

[0152] The swing frame has a rotation speed of 40 rpm;

[0153] The polishing liquid droplet acceleration is 1 mL / min;

[0154] The polishing time is 4.5 hours.

[0155] Comparative Example 1: Based on Example 1, in step 1, during melting, no high-transmittance and high-refractive additive was added, and 11 parts of the high-transmittance and high-refractive additive were replaced with 11 parts of silicon dioxide in equal amounts. The specific operation was as follows:

[0156] Step 1: Melting

[0157] The 11 parts of high light transmittance and high refractive index additive were replaced by 11 parts of silicon dioxide, and the other operations were the same as in Example 1;

[0158] The operations of steps 2 and 3 are the same as those in Example 1.

[0159] Comparative Example 2: Based on Example 1, in step 1, melting, no aluminum borate was added to the compound clarifier, and 9 parts of the compound clarifier were replaced with 9 parts of cerium dioxide. The specific operation was as follows:

[0160] Step 1: Melting

[0161] No aluminum borate was added, and 9 parts of the composite clarifier were replaced by 9 parts of cerium dioxide. Other operations were the same as in Example 1.

[0162] The operations of steps 2 and 3 are the same as those in Example 1.

[0163] Comparative Example 3: Based on Example 1, in step 3, polishing, no mixed acid was added to the polishing liquid. Instead, 6 parts of mixed acid were replaced with 6 parts of deionized water. The specific operation was as follows:

[0164] The operations of steps 1 and 2 are the same as those in Example 1;

[0165] Step 3: Polishing

[0166] In the polishing liquid, 6 parts of mixed acid were replaced by 6 parts of deionized water, and other operations were the same as in Example 1.

[0167] Comparative Example 4: Based on Example 1, in step 3, polishing, no composite surfactant was added to the polishing liquid. Instead, 10 parts of the composite surfactant was replaced with 10 parts of deionized water. The specific operation was as follows:

[0168] The operations of steps 1 and 2 are the same as those in Example 1;

[0169] Step 3: Polishing

[0170] In the polishing liquid, 10 parts of the composite surfactant were replaced by 10 parts of deionized water, and the other operations were the same as in Example 1.

[0171] Performance testing:

[0172] The high-precision ultra-smooth optical glass obtained in Examples 1, 2, 3 and Comparative Examples 1, 2, 3, and 4 was tested for transmittance, refractive index, Abbe number, surface roughness, and other indicators:

[0173] 1. Light transmittance: Use UV-visible spectrophotometer (UV-6100) to measure the average light transmittance in the visible light band;

[0174] 2. Refractive index: measured in accordance with the test method specified in GB / T7962.1-2010 Test methods for colorless optical glass Part 1: Refractive index and dispersion coefficient;

[0175] 3. Abbe number: measured in accordance with the test method specified in GB / T7962.1-2010 Test methods for colorless optical glass Part 1: Refractive index and dispersion coefficient;

[0176] 4. Surface roughness: Dimention-3100 atomic force microscope (AFM) was used to detect surface roughness;

[0177] The results are shown in Table 1:

[0178] Table 1

[0179]

[0180] From the data in Table 1, it can be seen that the transmittance of Examples 1-3 is greater than 93%, the refractive index is 1.92 or above, the Abbe number is 40 or above, and the surface roughness is less than 0.24 nm, which shows that the optical glass obtained by the present invention has the excellent characteristics of high refractive index, low dispersion and high smoothness; in Comparative Example 1, no high-transmittance and high-refractive index additive is added. The transmittance of Comparative Example 1 is reduced to 81%, the refractive index is also greatly reduced to 1.64, the Abbe number is reduced to 33, and the surface roughness does not change, which shows that the high-transmittance and high-refractive index additive can effectively improve the transmittance and refractive index of the optical glass and reduce dispersion; in the composite clarifier of Comparative Example 2, no aluminum borate is added. The transmittance of Comparative Example 2 is reduced, the refractive index is also significantly reduced, the Abbe number is also reduced accordingly, and the surface roughness is not changed. There is almost no change, which shows that aluminum borate plays a vital role in ensuring the efficient clarification of optical glass; no mixed acid is added to the polishing liquid of Comparative Example 3, the transmittance and refractive index of Comparative Example 3 are reduced, the Abbe number does not change much, and the surface roughness is significantly increased, which shows that the mixed acid has a very significant effect on promoting the smoothness of the optical glass polishing process, and the decrease in smoothness also has a negative effect on the transmittance, refractive index and dispersion to a certain extent; no composite surfactant is added to the polishing liquid of Comparative Example 4, the transmittance of Comparative Example 4 is reduced to 89%, the refractive index is also significantly reduced, the Abbe number is slightly reduced, and the surface roughness is increased to 0.776nm, which shows that the composite surfactant plays a very important role in promoting the efficient polishing of the polishing liquid and improving the smoothness of the glass surface.

[0181] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A method for preparing high-precision ultra-smooth optical glass, characterized by: The method for preparing the high-precision ultra-smooth optical glass includes three steps: melting, forming, and polishing; The melting process comprises preliminarily mixing silicon dioxide, aluminum oxide, sodium oxide, magnesium oxide, calcium oxide, lithium oxide, flux, compound clarifying agent, and high-transmittance and high-refractive additive according to the raw material composition of high-precision ultra-smooth optical glass in parts by weight, and then placing the mixture in a glass melting furnace, and melting the mixture into a high-temperature glass melt after a heating and constant temperature process. The raw material composition of the high-precision ultra-smooth optical glass, in parts by weight, is specifically 60-100 parts of silicon dioxide, 25-70 parts of aluminum oxide, 15-50 parts of sodium oxide, 10-25 parts of magnesium oxide, 10-40 parts of calcium oxide, 5-25 parts of lithium oxide, 5-9 parts of flux, 3-10 parts of compound clarifier, and 5-13 parts of high-transmittance and high-refractive additive; The compound clarifier is a mixture of cerium dioxide and aluminum borate; The high-transmittance and high-refractive additive is a mixture of lanthanum disilicide and samarium disilicide; The polishing process includes chemically and mechanically polishing a high-precision ultra-smooth optical glass semi-finished product using a uniaxial grinding and polishing machine and a polyurethane polishing pad, controlling the spindle speed, swing frame speed, polishing liquid droplet acceleration, and polishing time. After polishing, the semi-finished product is washed with deionized water and dried with clean compressed air to obtain a high-precision ultra-smooth optical glass product. The polishing liquid is composed of cerium oxide abrasive, tributyl phosphate, composite surfactant, mixed acid and deionized water; The composite surfactant is a mixture of fatty alcohol polyoxyethylene ether sodium sulfate and isooctyl alcohol polyoxyethylene ether JFC-2; The mixed acid is a mixture of mellitic acid and phosphoric acid.

2. The method for preparing high-precision ultra-smooth optical glass according to claim 1, characterized in that: The flux is sodium tetraborate; The mass ratio of cerium dioxide to aluminum borate is 10-57:100; The mass ratio of the lanthanum disilicide to the samarium disilicide is 25-80:

13.

3. The method for preparing high-precision ultra-smooth optical glass according to claim 1, characterized in that: The mass ratio of the fatty alcohol polyoxyethylene ether sodium sulfate and isooctyl alcohol polyoxyethylene ether JFC-2 is 30-90:17; The mixed acid is mellitic acid and phosphoric acid in a mass ratio of 10 to 47:30; The particle size of the cerium oxide abrasive is 50-400 nm.

4. The high-precision ultra-smooth optical glass prepared by the preparation method according to any one of claims 1 to 3, characterized in that: The high-precision ultra-smooth optical glass has a light transmittance of 93-94%, a refractive index of 1.92-1.96, an Abbe number of 40-43, and a surface roughness of 0.211-0.232 nm.

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