CN103253862B - A kind of low alkali low-melting point optical glass and preparation method thereof - Google Patents

Abstract

The present invention relates to a kind of low alkali low-melting point optical glass and preparation method thereof, its compositions in weight percentage comprises: B ₂o ₃: 30 ~ 65%; Al ₂o ₃: 0 ~ 18%; SiO ₂: 0 ~ 15%; BaO:5 ~ 35%; ZnO:0 ~ 26%; WO ₃: 0 ~ 22%; Nb ₂o ₅: 0 ~ 15%; La ₂o ₃: 15 ~ 35%; Gd ₂o ₃: 0 ~ 15%; Ta ₂o ₅: 0 ~ 15%; Li ₂o:0 ~ 10%; Na ₂o:0 ~ 15%; K ₂o:0 ~ 20%; Preparation comprises: found after being mixed by raw material, anneals after then being cast by the glass metal melted, last machine-shaping.Opticglass of the present invention has lower glass transformation temperature, middle low-expansion coefficient, medium refractive index, and containing appropriate rare-earth oxide, the harmful element such as not leaded, cadmium, is applicable to the once molding formed of opticglass.

Description

A kind of low alkali low-melting point optical glass and preparation method thereof

Technical field

The invention belongs to low alkali low melting glass and preparation field thereof, particularly low alkali low-melting point optical glass of one and preparation method thereof.

Background technology

Along with advancing by leaps and bounds of science and technology, mobile phone, the usage quantity of the optical element in the electronic products such as notebook increases by geometric progression, optical element dimension is to miniaturization, microminiaturized direction is fast-developing, this just makes optical element processing problems become more and more outstanding, it is also proposed higher requirement to the processing of optical element simultaneously, therefore there is opticglass compression molding technology in the seventies in last century, so-called opticglass compression molding technology, utilize the hot-work character that glass is continuous reversible from molten state to solid state transformed process exactly, near glass transformation temperature Tg, temperature-pressure is carried out to glass and mould, disposablely opticglass is molded into the optical element reaching service requirements, thus abandoned traditional corase grind, fine grinding, the operations such as polishing edging and centering, direct once shaped, greatly save the manpower that small-sized micro-optical component adds man-hour, material resources, shorten the process period of optical element, reduce the cost of optical element.Because this new technology revolutionizes traditional optical glass producing method, carry out temperature-pressure to glass blank and mould, disposablely glass molds is pressed into the service requirements reaching opticglass, this is just proposed very high requirement to glass and mould.

Glass optical component compression molding technology is a complex art, the method for glass ware forming, the kind of glass and base substrate, moulding stock and mold machining technology, be all glass molds molded in gordian technique.For opticglass, the parameters such as glass composition, material property, the coefficient of expansion, transition temperature are the keys of mould pressing technology, glass expansion coefficient is lower, the stress that glass produces in mold process is less, and mold pressing yield rate is higher, and glass expansion coefficient is higher, in suddenly cold and hot process before and after compression moulding, inside glass stress is larger, and glass is easier to be damaged, and the glass that thus coefficient of expansion is large is not suitable for the precise compression molding of low cost.The transition temperature of glass is low, significantly can extend the life-span of molding die like this and improve the qualification rate of product, ensure glass optical component smooth surface, smooth or good curvature, therefore, for being suitable for this new opticglass mould pressing technology, require to develop the opticglass component made new advances, to meet this new technology, novel process, this new glass composition must take into account the transition temperature of glass and the coefficient of expansion of glass, and glass transformation temperature as far as possible low (being less than 500 DEG C) and thermal expansivity is as far as possible little (is less than 85 × 10 ^-7/ DEG C), be suitable for the once molding formed of opticglass.

United States Patent (USP) 7,767,605 component and the preparation methods disclosing a kind of niobate phosphate low-melting-point point opticglass.Main ingredient is as follows: P ₂o ₅15to35%, Nb ₂o ₅35to60%, Na ₂o0.1to is less than 15%, BaO0to and is less than 25%, Gd ₂o ₃0to5%, K ₂o0to10%, Li ₂o0to10%, Bi ₂o ₃0to15%, MgO0to10%, CaO0to10%, SrO0to10%, ZnO0to3%, SiO ₂0to5%, B ₂o ₃0to5%, Al ₂o ₃0to4%, Ta ₂o ₅0to5%, ZrO ₂0to3%, TiO ₂0to10%, WO ₃0to20%andSb ₂o ₃0to0.1%.This patent selects niobate phosphate system to prepare low-melting point optical glass, and has higher specific refractory power and dispersion, but in this patent, the transition temperature of glass, on 600 DEG C, is not suitable for the compression molding of optical element.

Disclosed in Japanese Patent 2012-211041, glass consists of 20.0-40.0wt.%B ₂o ₃, 1.0-10.0wt.%SiO ₂, 0.1-8.0wt.%Al ₂o ₃, 3.0-15.0wt.%RO, 10.0-40.0wt.%R ₂o, 10.0-40.0wt.%ZnO, 1.0-15.0wt.%WO ₃, 12.0wt.% or less Ln ₂o ₃, 0-5.0%TiO ₂.Wherein R ₂represent Li, Na, K; R represents Mg, Ca, Sr, Ba; Ln represents Y, La, Gd, and this patent is used for the preparation of middle light.R in patent ₂o content is within the scope of 10.0-40.0wt.%, alkali metal content is high, the transition temperature of glass can be reduced, but also make the chemical stability of glass decline, thermal expansivity significantly improves, the life-time service of this unfavorable optical element, does not mention adding due to alkalimetal oxide in patent, on the impact of glass expansion coefficient, also containing TiO in patent ₂, also can reduce the stability of glass system.

Summary of the invention

Technical problem to be solved by this invention is to provide a kind of low alkali low-melting point optical glass and preparation method thereof, this glass has lower glass transformation temperature, middle low-expansion coefficient, medium refractive index, containing appropriate rare-earth oxide, the harmful elements such as not leaded, cadmium, are applicable to the once molding formed of opticglass.

The low alkali low-melting point optical glass of one of the present invention, its component is by comprising by weight percentage: B ₂o ₃: 30 ~ 65%; Al ₂o ₃: 0 ~ 18%; SiO ₂: 0 ~ 15%; BaO:5 ~ 35%; ZnO:0 ~ 26%; WO ₃: 0 ~ 22%; Nb ₂o ₅: 0 ~ 15%; La ₂o ₃: 15 ~ 35%; Gd ₂o ₃: 0 ~ 15%; Ta ₂o ₅: 0 ~ 15%; Li ₂o:0 ~ 10%; Na ₂o:0 ~ 15%; K ₂o:0 ~ 20%.

Wherein B ₂o ₃, Al ₂o ₃, SiO ₂weight percent sum be 45 ~ 65%, wherein B ₂o ₃with Al ₂o ₃and SiO ₂the weight ratio of sum is greater than 2; Described La ₂o ₃with Gd ₂o ₃weight percent sum be 15 ~ 32%, wherein La ₂o ₃with Gd ₂o ₃ratio be greater than 2; Described Li ₂o, Na ₂o and K ₂o weight percent sum is 3 ~ 25%.

B in described glass ingredient ₂o ₃preferable range: 35 ~ 50%; Al ₂o ₃preferable range: 3 ~ 12%; SiO ₂preferable range: 2 ~ 8%.B ₂o ₃+ Al ₂o ₃+ SiO ₂preferable range 45 ~ 65%.B ₂o ₃be the main component of glass, in glass as Network former, form the three-dimensional network of glass, play and reduce the transition temperature of glass and the effect of softening temperature, Al ₂o ₃effect be change B ₂o ₃structure in glass, makes B ₂o ₃by boron oxygen triangle body [BO ₃] change into boron oxygen tetrahedron [BO ₄], thus reach the object of reinforced glass network structure.A small amount of SiO ₂can the connection of Strengthens network, reduce the suspension degree in network, also can improve the chemical stability of glass simultaneously.

B in described glass ingredient ₂o ₃content must be greater than Al ₂o ₃+ SiO ₂content, and (B ₂o ₃)/(Al ₂o ₃+ SiO ₂) ratio be greater than 2.

Al in described glass ingredient ₂o ₃+ SiO ₂preferable range 5 ~ 20%.SiO ₂content is unsuitable too high, otherwise borate glass system can be caused to produce phase-splitting or crystallization.

The preferable range of BaO in described glass ingredient: 8 ~ 12%.BaO can strengthen the forming range of glass, improves the material property of glass, regulates specific refractory power and the thermal expansivity of glass.

The preferable range of ZnO in described glass ingredient: 4 ~ 15%.Appropriate ZnO can strengthen the forming range of glass, reduces glass transformation temperature and thermal expansivity.

La in described glass ingredient ₂o ₃preferable range: 15 ~ 25%; Gd ₂o ₃preferable range: 3 ~ 7%; La ₂o ₃+ Gd ₂o ₃preferable range: 15 ~ 32%; La ₂o ₃/ Gd ₂o ₃ratio should be greater than 2.La ₂o ₃and Gd ₂o ₃introducing can improve glass smelting condition, reduce the transition temperature of glass and softening temperature.

WO in described glass ingredient ₃preferable range: 5 ~ 10%, Nb ₂o ₅preferable range: 0 ~ 5%, Ta ₂o ₅preferable range: 0 ~ 5%, object strengthens glass forming ability, ensures that glass forms good vitreous state and stable, and the specific refractory power of adjustable glass and transition temperature.

Li in described glass ingredient ₂o preferable range: 0 ~ 6%; Na ₂o preferable range: 0 ~ 10%; K ₂o preferable range: 0 ~ 12%; Li ₂o+Na ₂o+K ₂o:3 ~ 25%.Li ₂o, Na ₂o, K ₂o is important and necessary composition of the present invention, in order to regulate the thermal expansivity of glass, regulates transition temperature and the softening temperature of glass, improves material property and the mobility of glass.

The preparation method of a kind of low alkali low-melting point optical glass of the present invention comprises:

(1) mixed by each raw material, wherein boron oxide is introduced by boric acid, and aluminum oxide is introduced by aluminium hydroxide, and BaO is introduced by its carbonate, and all the other components are introduced by respective oxide compound;

(2) step (1) is obtained the raw material after mixing to found, anneal after then the glass metal melted being cast, last machine-shaping.

The temperature of founding described in step (2) is 1150 ~ 1300 DEG C, and the temperature of annealing is 480 ~ 500 DEG C.

The present invention selects borate salt system, by adding Al ₂o ₃and SiO ₂improving the contiguity of glass network, improving the Forming ability of glass by adding BaO, ZnO further, strengthen the forming region of glass, La ₂o ₃and Gd ₂o ₃add and can improve glass smelting condition, accelerate the clarification homogenizing of glass, particularly can regulate the specific refractory power of glass easily, also can reduce the transition temperature of glass; Li ₂o, Na ₂o, K ₂o, in order to regulate the thermal expansivity of glass, regulates transition temperature and the softening temperature of glass, improves material property and the mobility of glass.

Beneficial effect:

Opticglass of the present invention has lower glass transformation temperature (<500 DEG C), middle low-expansion coefficient (70 ~ 85 × 10 ^-7/ DEG C), medium refractive index (n _d=1.6 ~ 1.7), containing appropriate rare-earth oxide, the harmful element such as not leaded, cadmium, is applicable to the once molding formed of opticglass.

Embodiment

Below in conjunction with specific embodiment, set forth the present invention further.Should be understood that these embodiments are only not used in for illustration of the present invention to limit the scope of the invention.In addition should be understood that those skilled in the art can make various changes or modifications the present invention, and these equivalent form of values fall within the application's appended claims limited range equally after the content of having read the present invention's instruction.

Embodiment 1 ~ 6

According to technical characteristic described above, determine the composition (see table 1) of glass.

Described low-melting point optical glass preparation method comprises the steps:

A, selection raw material: boron oxide is introduced by boric acid, and aluminum oxide is introduced by aluminium hydroxide, BaO is introduced by its carbonate, and all the other components are introduced by respective oxide compound, then calculates formula, weighing mixes.

B, select quartz crucible, and cover lid, found in globars electric furnace, glass melting temperature is 1150 ~ 1300 DEG C, is incubated 1.5 ~ 3 hours.

C, the glass metal melted are cast into glass block or glass bar, put into annealing furnace and anneal, and annealing temperature is 480 ~ 500 DEG C, are incubated furnace cooling after 1 hour.

Test request machine-shaping pressed by glass after d, annealing.

Carry out the founding of glass, shaping and grinding according to the preparation for processing of above-mentioned glass, the sample after processing is tested.Glass composition (weight percent) of embodiment and the performance test results see the following form:

Table 1: low melting glass component and performance

	1	2	3	4	5	6
							SiO 2	3	3	3	3		3
B 2O 3	35	40	40	45	45	45
							Al 2O 3	5	3	3	3	5	3
BaO	12	20	10	10	12	20
							Na 2O	3	5	2	5		2

K 2O	2				5
							Li 2O	2	2	5		2	5
ZnO	12		10	6	4
							La 2O 3	15	22	22	20	20	20
Gd 2O 3	5	5		5	5
							Ta 2O 5	4			3
Nb 2O 5					2	2
							WO 3	2		5
n d	1.65	1.68	1.65	1.63	1.64	1.64
							α(×10 -7/℃)	75.7	84.2	78.7	64.5	72.7	79.5
Tg(℃)	470	464	464	475	466	458
							Tf(℃)	494	492	496	509	495	488

Claims (3)

1. a low alkali low-melting point optical glass, is characterized in that: its component is composed of the following components, by weight percentage, and B ₂o ₃: 45%; Al ₂o ₃: 3%; SiO ₂: 3%; BaO:20%; La ₂o ₃: 20%; Li ₂o:5%; Na ₂o:2%; Nb ₂o ₅: 2%.

2. the preparation method of low alkali low-melting point optical glass as claimed in claim 1, comprising:

(1) mixed by each raw material, wherein boron oxide is introduced by boric acid, and aluminum oxide is introduced by aluminium hydroxide, and BaO is introduced by its carbonate, and all the other components are introduced by respective oxide compound;

(2) step (1) is obtained the raw material after mixing to found, anneal after then the glass metal melted being cast, last machine-shaping.

3. the preparation method of low-melting point optical glass according to claim 2, is characterized in that: the temperature of founding described in step (2) is 1150 ~ 1300 DEG C, and the temperature of annealing is 480 ~ 500 DEG C.