CN107129140B

CN107129140B - Optical glass and optical element

Info

Publication number: CN107129140B
Application number: CN201710438267.2A
Authority: CN
Inventors: 毛露路; 匡波
Original assignee: CDGM Glass Co Ltd
Current assignee: CDGM Glass Co Ltd
Priority date: 2014-01-20
Filing date: 2014-01-20
Publication date: 2020-09-29
Anticipated expiration: 2034-01-20
Also published as: CN104788017A; CN107129140A; CN104788017B

Abstract

The invention provides an optical glass and an optical element which have a refractive index of 1.66-1.73 and an Abbe number of 48-53 and are suitable for precision press molding. The optical glass comprises the following components in percentage by weight: SiO 2₂6‑16％、B₂O₃22‑40％、La₂O₃10‑24％、ZnO 20‑30％、Nb₂O₅1‑5％、ZrO₂1-4%, CaO 6-16%, and Ta-free₂O₅、Li₂O and Ga₂O₃. The optical glass has Tg temperature of 560-610 deg.c and density lower than 3.85g/cm³(ii) a Lambda 80 is less than 375nm and does not contain Ta₂O₅、Ga₂O₃And the like. The optical glass is suitable for aspheric surface precision mould pressing.

Description

Optical glass and optical element

The present application is a divisional application of an invention patent application having an application number of 201410024911.8, an application date of 2014, 1/20, and a name of "optical glass and optical element".

Technical Field

The invention relates to optical glass, in particular to optical glass with a refractive index of 1.66-1.73 and an Abbe number of 48-53 and an optical element.

Background

In recent years, with the rapid development of aspheric surface technology of optical glass, the optical imaging system can be miniaturized and lightened. Meanwhile, the aspheric lens can eliminate spherical aberration and aberration of the optical system, and excellent imaging quality is obtained.

At present, the main method for manufacturing the aspheric lens is to soften optical glass in a common mould, press the optical glass into a prefabricated part, then place the prefabricated part into a mould with a high-precision surface for heating again, and press the prefabricated part into the aspheric lens. The surface precision of the aspheric surface die is very high, the surface quality of a pressed finished product is also very good, and the aspheric surface die can be directly installed for use. The manufacturing method has the advantages that the subsequent working procedures such as processing, grinding and the like are reduced, the cost can be saved, and the emission of harmful substances such as grinding fluid, grinding powder, adhesive and the like used in the subsequent working procedures can be reduced.

The precision surface of the aspherical precision profiling mold is easily oxidized in air due to use at high temperature, and the higher the temperature is, the faster the oxidation speed is. The manufacturing cost of the precision profiling mold is expensive, and the too short service life of the mold can greatly improve the manufacturing cost of the aspheric lens. Thus, the optical glass used for manufacturing the aspherical lens is required to have a low transition temperature (hereinafter, referred to as Tg temperature), and from the production practical point of view, if the Tg temperature of the glass is lower than 610 ℃, the service life of the mold is greatly prolonged. Therefore, optical glass with a Tg lower than 610 ℃ is very important for aspheric profiling technology.

The current mainstream lens (such as single lens reflex lens) is usually composed of more than ten optical glass lenses. If the transmittance of each optical glass lens is not high, the luminous flux of light projected to the photosensitive element after passing through more than ten lenses is greatly reduced, thereby affecting the imaging quality. Therefore, modern optical design techniques require optical glass having a high transmittance. An important index for measuring the transmittance of optical glass is the degree of coloration. The degree of coloration is represented by λ 80/λ 5. I.e. a sample thickness of 10mm + -0.1 mm, lambda 80 is the wavelength corresponding to a glass transmittance of 80%, lambda 5 is the wavelength corresponding to a glass transmittance of 5%. For a general imaging apparatus, the lower the value of λ 80, the better.

CN99812067.7 discloses an optical glass, the component of which contains Ta₂O₅Although this oxide improves the devitrification resistance of the glass, it is extremely expensive and contains 2.5 to 8% of Li₂O,Li₂The addition of O to the glass lowers the Tg but also decreases the devitrification resistance of the glass.

CN102674686A discloses an optical glass, which contains 21-25% of SiO₂8-14% of B₂O₃2-5% of TiO₂。SiO₂High content of B₂O₃The smelting temperature is increased when the content is lower, and particularly, the components contain TiO₂In the case of (2), the degree of coloration of the optical glass is increased.

CN99105396.6 discloses an optical glass, which contains 29-43.5% of B₂O₃27-40% of La₂O₃3.5 to 10 percent of ZnO and 0.1 to 3.5 percent of TiO₂And 5-9% of ZrO₂。B₂O₃Will have a reduced refractive index and dispersion contribution to the glass, the glass having to reach a higher refractive index potentialIt is necessary to add more La₂O₃And a high refractive oxide, which increases the cost. In addition, a lower content of ZnO is not conducive to lowering the Tg of the glass. In particular, the components contain more difficult-to-melt ZrO₂Increase the glass dissolution temperature and at the same time, in TiO₂In the case of addition, deterioration of the glass coloring degree is caused.

Disclosure of Invention

The invention aims to solve the technical problem of providing optical glass and an optical element which have the refractive index of 1.66-1.73 and the Abbe number of 48-53 and are suitable for precision compression molding.

The technical scheme adopted by the invention for solving the technical problem is as follows: the optical glass comprises the following components in percentage by weight: SiO 2₂6-16％、B₂O₃22-40％、La₂O₃10-24％、ZnO 20-30％、Nb₂O₅1-5％、ZrO₂1-4%, CaO 6-16%, and Ta-free₂O₅、Li₂O and Ga₂O₃。

Further, it contains BaO 0-10%, SrO 0-6%, and Sb₂O₃0-0.1％。

Further, the weight percentage composition is as follows: SiO 2₂6-16％、B₂O₃22-40％、La₂O₃10-24％、ZnO20-30％、Nb₂O₅1-5％、ZrO₂1-4％、CaO 6-16％、BaO 0-10％、SrO 0-6％、Sb₂O₃0-0.1％。

Further, wherein SiO₂7-11% and/or B₂O₃26-38% and/or La₂O₃12-22% and/or ZnO 22-28% and/or Nb₂O₅2-4% and/or ZrO₂1.5-3.5% and/or CaO 8-12%.

Further, the glass transition temperature is 560 ℃ to 610 ℃.

Further, the glass λ 80 is less than 375 nm.

Furthermore, the glass has a refractive index of 1.66-1.73 and an Abbe number of 48-53.

Further, in the above-mentioned case,the density of the glass is less than 3.85g/cm³。

A glass preform made of the above optical glass.

An optical element made of the above optical glass.

The invention has the beneficial effects that: by reasonably arranging the content of each component, the Tg temperature of the optical glass is 560-610 ℃, and the density is lower than 3.85g/cm³(ii) a Lambda 80 is less than 375nm and does not contain Ta₂O₅、Ga₂O₃And the like. The optical glass is suitable for aspheric surface precision mould pressing.

Detailed Description

The respective components of the optical glass of the present invention will be described below, and unless otherwise specified, the contents of the respective components are expressed in% by weight.

B₂O₃Is a network former which acts as a skeleton in the glass, in the present invention if B is₂O₃Less than 22%, the chemical stability and the degree of coloration of the glass are reduced; if the content is more than 40%, the glass will not achieve the refractive index and dispersion required by the present invention. Therefore, B in the present invention₂O₃The content is limited to 22-40%, preferably 26-38%.

SiO₂Is also a network former when SiO₂When the borate glass is added, the high-temperature viscosity of the glass can be improved, the glass forming is facilitated, and the glass without stripes can be easily obtained. In addition, SiO₂The chemical stability of the glass can also be improved. In the present invention, if the content thereof is less than 6%, the effect of improving high temperature viscosity and chemical stability thereof is not significant; if the content thereof is more than 16%, the dissolution temperature of the glass is significantly raised and the Tg temperature of the glass is also raised. Thus, SiO₂The content is limited to 6 to 16%, preferably 7 to 11%.

ZnO can adjust the refractive index and Abbe number of the glass and can lower the Tg temperature of the glass. In addition, the addition of a large amount of ZnO into the glass can obviously improve the refractive index and dispersion of the glass and can replace part of rare earth oxides. In the present invention, when the content of ZnO is less than 20%, the effect of lowering the Tg temperature is not significant; however, when the content exceeds 30%, the chemical stability and devitrification resistance of the glass are deteriorated. Therefore, the ZnO content is limited to 20 to 30%, preferably 22 to 28%.

La₂O₃The rare earth oxide has higher refractive index and lower dispersion, and can remarkably improve the refractive index and Abbe number of the glass when being added into the glass. The content thereof is limited to 10 to 24% in the present invention. The content is preferably 12 to 22% because too high or too low content does not make the glass meet the design requirements.

Nb₂O₅Is a metal oxide with high refraction and high dispersion, and is mainly used for adjusting the refractive index and the Abbe number of glass. The content thereof is limited to 1 to 5% in the present invention. The content is preferably 2-4% because too high or too low content does not make the glass meet the design requirements.

ZrO₂The chemical stability of the glass can be improved, and the refractive index and dispersion of the glass can be adjusted. In the present invention, if the content thereof is less than 1%, the effect of improving chemical stability is not significant; if the content thereof is more than 4%, the dissolution temperature of the glass is remarkably increased. Therefore, the content thereof is limited to 1 to 4%, preferably 1.5 to 3.5%.

In the present invention, CaO, BaO and SrO are all alkaline earth metal oxides, and are added to glass to adjust the optical constants of the glass and balance the components.

CaO is an oxide which is necessary to be added in the invention, and if the content of CaO is less than 6 percent in the invention, the effect of the invention cannot be achieved; if it exceeds 16%, deterioration of devitrification resistance of the glass is caused. Therefore, the content thereof is limited to 6 to 16%, preferably 8 to 12%.

The SrO content in the present invention is limited to 0-4%, and is preferably not added.

The content of BaO in the present invention is limited to 0 to 10%, and if the added amount exceeds 10%, the glass density increases significantly. Preferably without addition.

Sb₂O₃Is a fining agent added into glass to make bubblesThe elimination becomes easier. In the present invention, the content is limited to 0 to 0.1%, and it is preferably not added.

The properties of the optical glass of the present invention will be described below:

the refractive index and Abbe number are tested according to the GB/T7962.1-2010 colorless optical glass test method refractive index and dispersion coefficient. The refractive index (n) of the high-refractive-index high-dispersion optical glass of the invention is measured_d) Is 1.66-1.73, Abbe number (v)_d) Is 48-53.

The density was measured according to GB/T7962.20-2010 colorless optical glass test method Density test method. The density (. rho.) of the present invention was found to be 3.85g/cm³The following.

The transition temperature (Tg) was measured according to GB/T7962.16-2010 colorless optical glass test method. The Tg temperature of the present invention was measured to be between 560 ℃ and 610 ℃.

The degree of coloration is represented by λ 80/λ 5. I.e. a sample thickness of 10mm + -0.1 mm, measured with a spectrophotometer, lambda 80 refers to the wavelength corresponding to a glass transmittance of 80%, lambda 5 refers to the wavelength corresponding to a glass transmittance of 5%.

Through tests, the optical glass of the invention has the following properties: a refractive index (nd) of 1.66 to 1.73, an Abbe number (vd) of 48 to 53, and a density (. rho.) of 3.85g/cm³Hereinafter, the lambda 80 is lower than 375nm, and the Tg temperature is between 560 ℃ and 610 ℃.

The present invention also provides an optical glass preform and an optical element formed from the above optical glass according to a method well known to those skilled in the art. The optical glass has high refractive index and high dispersion, so the optical element also has high refractive index and high dispersion, and can be applied to equipment such as digital cameras, digital video cameras, camera phones and the like.

Examples

In order to further understand the technical solution of the present invention, examples of the optical glass of the present invention will now be described. It should be noted that these examples do not limit the scope of the present invention.

The optical glasses (examples 1 to 20) shown in tables 1 to 2 were obtained by weighing and mixing the ordinary raw materials (such as oxides, hydroxides, carbonates, nitrates, etc.) for optical glasses in the ratios of the respective examples shown in tables 1 to 2, placing the mixed raw materials in a platinum crucible, melting at 1320-1380 ℃ for 2.5 to 4 hours, and obtaining a homogeneous molten glass free of bubbles and of undissolved substances after clarification, stirring and homogenization, and casting and annealing the molten glass in a mold.

The compositions of examples 1 to 20 of the present invention are shown in tables 1 to 2 together with the results of refractive index (nd), Abbe number (vd), density (. rho.), and. lamda.80. In these tables, the compositions of the respective components are expressed in% by weight.

TABLE 1

TABLE 2

Claims

1. The optical glass is characterized by comprising the following components in percentage by weight: SiO 2₂6-16％、B₂O₃22-40％、La₂O₃10-24％、ZnO 20-30％、Nb₂O₅1-5％、ZrO₂1-4 percent of CaO, 10.20-16 percent of CaO, and does not contain Ta₂O₅、Li₂O and Ga₂O₃。

2. The optical glass is characterized by comprising the following components in percentage by weight: SiO 2₂6-16％、B₂O₃22-38.80％、La₂O₃10-24％、ZnO 20-30％、Nb₂O₅1-5％、ZrO₂1-4％、CaO 6-16％、BaO 0-10％、SrO 0-6％、Sb₂O₃0-0.1％。

3. The optical glass is characterized by comprising the following components in percentage by weight: SiO 2₂6-16％、B₂O₃22-40％、La₂O₃10-24％、ZnO 22-29.90％、Nb₂O₅1-5％、ZrO₂1-4%, CaO 6-16%, and Ta-free₂O₅、Li₂O and Ga₂O₃。

4. An optical glass according to claim 1 or 3, further comprising 0 to 10% of BaO, 0 to 6% of SrO, and Sb₂O₃0-0.1％。

5. The optical glass according to claim 1, wherein SiO is₂7-11% and/or B₂O₃26-38% and/or La₂O₃12-22% and/or ZnO 22-28% and/or Nb₂O₅2-4% and/or ZrO₂1.5-3.5% and/or CaO10.20-12%.

6. An optical glass according to claim 3, wherein SiO is₂7-11% and/or B₂O₃26-38% and/or La₂O₃12-22% and/or ZnO 22-28% and/or Nb₂O₅2-4% and/or ZrO₂1.5-3.5% and/or CaO 8-12%.

7. The optical glass according to claim 2, wherein SiO is₂7-11% and/or B₂O₃26-36% and/or La₂O₃12-22% and/or ZnO 22-28% and/or Nb₂O₅2-4% and/or ZrO₂1.5-3.5% and/or CaO 8-12%.

8. An optical glass according to any of claims 1 to 3, wherein the glass transition temperature is from 560 ℃ to 610 ℃.

9. An optical glass according to any of claims 1 to 3, wherein the glass λ₈₀Less than 375 nm.

10. An optical glass according to any of claims 1 to 3, wherein the glass has a refractive index of 1.66 to 1.73 and an Abbe number of 48 to 53.

11. An optical glass according to any of claims 1 to 3, wherein the glass has a density of less than 3.85g/cm³。

12. A glass preform made of the optical glass as claimed in any one of claims 1 to 11.

13. An optical element produced by using the optical glass according to any one of claims 1 to 11.