CN-116655253-B - Hot press molding method for optical glass element

CN116655253BCN 116655253 BCN116655253 BCN 116655253BCN-116655253-B

Abstract

The invention provides a hot press molding method of an optical glass element capable of preventing a glass preform from being stuck on a mold, which comprises the following steps of depositing a boron nitride film layer on the surface of the glass preform, and preparing the optical glass element by hot press molding, wherein the thickness of the boron nitride film layer on the surface of the glass preform is less than or equal to 15nm, and the surface of the optical glass element after hot press molding is wrapped with at least one boron nitride film layer with atomic layer thickness or at least one boron nitride film layer with 0.65nm thickness. The PVD or CVD boron nitride film layer can prevent active hydrogen in hydrogen-containing DLC from entering the glass preform in the film forming process, prevent atomization, blurring and damage to the film surface of an optical glass element, reduce the mold separation difficulty in the mold pressing process and improve the production automation capability and the mold pressing stability.

Inventors

DU ZHONGYANG
WANG YONGKANG
LI SONG
WANG HONGCHENG
XIANG QINGYUN

Assignees

成都光明南方光学科技有限责任公司

Dates

Publication Date: 20260505
Application Date: 20230620

Claims (9)

1. The hot press forming method of the optical glass element is characterized by comprising the steps of depositing a boron nitride film layer on the surface of a glass preform, then forming the optical glass element through hot press forming, wherein the thickness of the boron nitride film layer on the surface of the glass preform is smaller than or equal to 15nm, the surface of the optical glass element after hot press forming is at least wrapped with a boron nitride film layer with the thickness of an atomic layer, or the surface of the optical glass element after hot press forming is at least wrapped with a boron nitride film layer with the thickness of 0.65nm, the boron nitride film layer is deposited on the surface of the glass preform, the glass preform is heated for 30s-210min under the environment of 300 ℃ to 500 ℃ before the boron nitride film layer is deposited, then the boron nitride film layer is deposited on the surface of the glass preform through 600V-1050V of voltage ionization gas under the environment of 5.0X10- 0 Pa-1.0×10 -4 Pa, the boron nitride film layer is deposited in a CVD or PVD mode, the PVD mode comprises magnetron sputtering and FCVA, and the target material is ammonia borane, urea and boric acid.
2. The method for hot press molding an optical glass element according to claim 1, wherein the thickness T of the boron nitride film layer on the surface of the glass preform satisfies: In the above formula, S (PF) represents the surface area of the glass preform; s (L) represents the surface area of the optical glass element.
3. The hot press molding method of an optical glass element according to claim 1 or 2, wherein a monitor is doped on a surface layer of the glass preform, a change in concentration of the monitor on the surface of the optical glass element is measured after hot press molding to determine an expansion ratio S (L)/S (PF) of a largest portion of surface area expansion of the glass preform, and a change in thickness of the boron nitride film layer is analyzed simultaneously.
4. The hot press molding method of an optical glass element according to claim 1 or 2, wherein the maximum film thickness variation region is determined by simulating a press molding variation.
5. The hot press molding method of an optical glass element according to claim 1 or 2, wherein each region on the glass preform is marked with a series of regular patterns, and the surface area expansion ratio of each point is calculated by the increase of each pattern compared with the glass preform after hot press molding.
6. The hot press molding method of an optical glass element according to claim 1 or 2, wherein a maximum elongation of a surface area generated by press molding is determined before the surface of the glass preform is formed with the boron nitride film layer, and a minimum thickness at which the boron nitride film layer is to be formed on the glass preform is determined based on the elongation.
7. The hot press molding method of an optical glass element according to claim 1 or 2, wherein a mold separation film is provided on a substrate surface of the mold.
8. The method of hot press molding an optical glass element according to claim 7, wherein the mold separation film is a diamond-like film.
9. The method for hot press molding an optical glass element according to claim 7, wherein the mold separation film is a hydrogenated diamond-like film, a tetrahedral amorphous carbon film, a hydrogenated tetrahedral amorphous carbon film, an amorphous carbon film, a hydrogenated amorphous carbon film, a carbon-based film, or an alloy film.

Description

Hot press molding method for optical glass element Technical Field The present invention relates to a method for manufacturing an optical glass element, and more particularly, to a method for obtaining an optical glass element by heat-softening and press-molding a glass preform. Background In the process of softening a glass preform by thermal contact to obtain an optical glass element (such as a lens), a diamond-like film, a noble metal film, a titanium-based film, which is mainly composed of carbon, is provided on the surface of a mold to prevent fusion of the glass preform with the surface of a mold base, thereby achieving good mold separation performance. However, when the glass preform used is a material of a hot-pressed product which is liable to cause cracks or defects itself during hot press molding, such as boric acid-based, phosphoric acid-based, fluorophosphoric acid-based glass, it is difficult to obtain a sufficient mold separation effect. The formation of a carbon film on the surface of a glass preform is a known technique for preventing adhesion of optical glass elements, but these coatings have some drawbacks, namely 1) the carbon film is commonly coated by CVD (chemical vapor deposition), the gas is C XHY (hydrocarbon), the gas is hydrogen-containing gas, the film is also hydrogen-containing DLC (diamond-like carbon film), hydrogen generated after decomposition may cause reduction of oxide glass, and 2) the stable region of the hydrogen-containing DLC is below 400 ℃, and the film is extremely decomposed during the molding process of high softening point glass, resulting in failure of the film. Both of the above defects may cause the glass preform to adhere to the mold. Disclosure of Invention The technical problem to be solved by the invention is to provide a hot press molding method of an optical glass element, which can prevent a glass preform from being stuck on a die. The technical scheme includes that the hot press forming method of the optical glass element comprises the following steps of depositing a boron nitride film layer on the surface of a glass preform, and then forming the optical glass element through hot press forming, wherein the thickness of the boron nitride film layer on the surface of the glass preform is less than or equal to15 nm, the surface of the optical glass element after hot press forming is wrapped with at least one boron nitride film layer with atomic layer thickness, or the surface of the optical glass element after hot press forming is wrapped with at least one boron nitride film layer with 0.65nm thickness. Further, the thickness T of the boron nitride film layer on the surface of the glass prefabricated member meets the following conditions: 0.65×S(L)÷S(PF)<T≤15(nm) In the above formula, S (PF) represents the surface area of the glass preform; s (L) represents the surface area of the optical glass element. Further, the boron nitride film layer is deposited on the surface of the glass preform by heating the glass preform for 30S-210min at 300-500 ℃ before depositing the boron nitride film layer, and then depositing the boron nitride film layer on the surface of the glass preform by ionizing gas at 600v-1050v under the vacuum degree of 5.0X10 0pa-1.0×10-4 Pa. Further, the boron nitride film layer is deposited in a CVD or PVD mode, the PVD mode comprises magnetron sputtering and FCVA, the CVD mode comprises PECVD, and the target material is ammonia borane or urea+boric acid. Further, the surface layer of the glass preform is doped with a monitoring agent, the concentration change of the monitoring agent on the surface of the optical glass element is measured after hot press molding to determine the expansion ratio S (L)/S (PF) of the largest expansion part of the surface area of the glass preform, and the thickness change of the boron nitride film layer is synchronously analyzed. Further, the maximum film thickness variation area is determined by simulating profiling variation. Further, each region on the glass preform is marked with a series of patterns having a certain rule, and after hot press molding, the surface area expansion ratio of each point is calculated by the increase of each pattern compared with the glass preform. Further, before forming the boron nitride film layer on the surface of the glass preform, a maximum expansion rate of the surface area generated by press molding is determined, and a minimum thickness of the boron nitride film layer to be formed on the glass preform is determined based on the expansion rate. Further, a mold separation film is provided on the surface of the base material of the mold. The mold separation film is, for example, a diamond-like film, a hydrogenated diamond-like film, a tetrahedral amorphous carbon film, a hydrogenated tetrahedral amorphous carbon film, an amorphous carbon film, a hydrogenated amorphous carbon film, a carbon-based film, or an alloy film. The method has the advantages that fusion and cracks