Optical glass and use thereof

Abstract

An aspect of the present invention relates to optical glass, which is oxide glass including cation components in the form of 10 to 40 cation % of P.sup.5+, equal to or more than 50 cation % of a combined quantity of Ti.sup.4+, Nb.sup.5+, W.sup.6+, Bi.sup.3+, and Te.sup.4+, with a cation ratio of a combined content of Ti.sup.4+ and Nb.sup.5+ to a combined content of W.sup.6+ and Bi.sup.3+ being equal to or less than 1.3, a combined quantity of B.sup.3+, Li.sup.+, Na.sup.+, K.sup.+, Rb.sup.+, Cs.sup.+, Mg.sup.2+, Ca.sup.2+, Sr.sup.2+, Ba.sup.2+, and Zn.sup.2+ which amounts to equal to or less than of a combined content of Ti.sup.4+, Nb.sup.5+, W.sup.6+, Bi.sup.3+, and Te.sup.4+, and more than 0 % of Li.sup.+, Na.sup.+, K.sup.+, Rb.sup.+, and Cs.sup.+ combined, and which has a refractive index of equal to or higher than 2.02.

Claims

1. An optical oxide glass, comprising cationic components that include: 10 to 40 cation % of P.sup.5+; 50 cation % or more of a combined content of Ti.sup.4+, Nb.sup.5+, W.sup.6+, Bi.sup.3+, and Te.sup.4+, a ratio of a combined content of Ti.sup.4+and Nb.sup.5+to a combined content of W.sup.6+and Bi.sup.3+,(Ti.sup.4++Nb.sup.5+)/(W.sup.6+Bi.sup.3+), being 0.9 or less; a combined content of B.sup.3+, Li.sup.+, Na.sup.+, K.sup.+, Rb.sup.+, Cs.sup.+, Mg.sup.2+, Ca.sup.2+, Sr.sup.2+, Ba.sup.2+, and Zn.sup.2+that is or less of the combined content of Ti.sup.4+, Nb.sup.5+, W.sup.6+, Bi.sup.3+, and Te.sup.4+; and more than 0% of a combined content of Li.sup.+, Na.sup.+, K.sup.+, Rb.sup.+, and Cs.sup.+; wherein the optical glass has a refractive index of 2.02 or more.

2. The optical glass according to claim 1, which comprises 0 to 4 cation % of Te.sup.4+as a cation component.

3. The optical glass according to claim 1, which has an Abbnumber vd of 18.0 or less.

4. The optical glass according to claim 1, which has a liquidus temperature of 1,100 C. or less.

5. A method of manufacturing optical glass, comprising: melting glass starting materials by heating to prepare glass melt, refining the glass melt, and molding the glass melt that has been refined; and blending the glass starting materials so as to obtain the optical glass according to claim 1.

6. The method of manufacturing optical glass according to claim 5, wherein the melting is conducted using a glass melting vessel made of platinum, platinum alloy, gold, or gold alloy.

7. A press molding glass material, comprising the optical glass according to claim 1.

8. An optical element, comprising the optical glass according to claim 1.

9. A method of manufacturing an optical element, comprising: preparing optical glass by processing the optical glass according to claim 1; and processing the optical glass that has been prepared to provide an optical element.

10. The optical glass according to claim 1, wherein a liquidus temperature is 960 C. or less.

11. The optical glass according to claim 1, wherein the ratio of (Ti.sup.4++Nb.sup.5+)/(W.sup.6++Bi.sup.3+) ranges from 0.74 to 0.90.

12. The optical glass according to claim 1, wherein the combined content of B.sup.3+, Li.sup.+, Na.sup.+, K.sup.+, Rb.sup.+, Cs.sup.+, Mg.sup.2+, Ca.sup.2+, Sr.sup.2+, Ba.sup.2+, and Zn.sup.2+is 0.12 to 0.225 of the combined content of Ti.sup.4+, Nb.sup.5+, W.sup.6+, Bi.sup.3+, and Te.sup.4+.

13. An optical oxide glass, comprising cationic components that include: 10 to 40 cation % of P.sup.5+; 50 cation % or more of a combined content of Ti.sup.4+, Nb.sup.5+, W.sup.6+, Bi.sup.3+, and Te.sup.4+, a ratio of a combined content of Ti.sup.4+and Nb.sup.5+to a combined content of W.sup.6+and Bi.sup.3+, (Ti.sup.4++Nb.sup.5+)/(W.sup.6++Bi.sup.3+), ranging from 0.74 to 0.90; a combined content of B.sup.3+, Li.sup.+, Na.sup.+, K.sup.+, Rb.sup.+, Cs.sup.+, Mg.sup.2+, Ca.sup.2+, Sr.sup.2+, Ba.sup.2+, and Zn.sup.2+that is 0.12 to 0.225 of the combined content of Ti.sup.4+, Nb.sup.5+, W.sup.6+, Bi.sup.3+, and Te .sup.4+; and more than 0% of a combined content of Li.sup.+, Na.sup.+, K.sup.+, Rb.sup.+, and Cs.sup.+; wherein the optical glass has a refractive index of 2.02 or more and the liquidus temperature is 960 C. or less.

Description

EXAMPLES

(1) The present invention will be further described through Examples below. However, the present invention is not limited to the embodiments shown in Examples.

Example 1

(2) Compound starting materials corresponding to various components were weighed out so as to yield glasses having compositions 1 to 14 in Table 1 and thoroughly mixed to obtain blended starting materials. In the glass compositions given in Table 1, the values denoted as cation % are the bases. The anion components of the oxide glasses having the compositions of Nos. 1 to 14 were entirely O.sup.2.

(3) Each of the blended starting materials was then charged to a quartz crucible and melted for 0.5 to 1.5 hours while being stirred at 1,100 C. to 1,200 C., quenched, and crushed to obtain cullets.

(4) Next, the cullets that had been obtained were charged to a crucible made of noble metal in the form of platinum or gold, heated to the liquidus temperature LT+20 C. to LT+80 C., stirred, and melted. The glass melt was then refined over 0.5 to 3 hours at a temperature at which the glass exhibited the viscosity of 1.0 dPa.Math.s50 C., desirably a temperature at which the glass exhibited the viscosity of 1.0 dPa.Math.s20 C. Following refining, the temperature of the glass was lowered from the refining temperature to the liquidus temperature LT to LT+60 C. The glass melt was then caused to flow out through a pipe connected to the bottom of the crucible, or cast into a casting mold, and molded into glass blocks. The temperature setting when employing a crucible made of noble metal in the form of gold was equal to or lower than 1,050 C., which was lower than the melting point of gold.

(5) When light beams were directed into the various glass blocks obtained and the optical paths of the light rays through the glass were observed from the side, no foreign material such as crystals was found in the glass. The optical glass obtained was determined to be highly homogeneous and of high quality.

(6) The refractive index nd, Abb number vd, liquidus temperature, temperature at which the glass exhibited the viscosity of 1.0 dPa.Math.s, glass transition temperature, specific gravity, 70, and 5 were measured as set forth below for each of the optical glass Nos. 1 to 14 obtained.

(7) (1) Refractive Index nd and Abb Number vd

(8) Measurement was conducted based on Standard JOGIS-01 of the Japan Optical Glass Manufacturers' Association.

(9) (2) Liquidus Temperature LT and Temperature at Which Glass Exhibited the Viscosity of 1.0 dPa.Math.s

(10) The glass sample was placed within an oven that had been heated to a prescribed temperature and maintained for two hours. Following cooling, the interior of the glass was observed by an optical microscope at 100-fold magnification to determine the liquidus temperature from the absence or presence of crystals. The viscosity was measured by a viscosity measuring method based on viscosity JIS standard Z8803 with a coaxial double-cylinder rotational viscometer, and the temperature at which the glass exhibited the viscosity of 1.0 dPa.Math.s was determined.

(11) (3) Glass Transition Temperature Tg

(12) The glass transition temperature was measured with a differential scanning calorimeter DSC3300SA from the endothermic curve when the temperature of the glass in a solid state was raised. The Tg that was measured by this measurement method correlated with the Tg measured based on Standard JOGIS-08 of the Japan Optical Glass Manufacturers' Association. The measurement results are given in Table 1.

(13) (4) Specific Gravity

(14) The specific gravity was measured based on Standard JOGIS-05 of the Japan Optical Glass Manufacturers' Association. The measurement results are given in Table 1.

(15) (5) 70, 5

(16) 70 and 5 were measured as follows. A glass sample 10 mm thick having flat surfaces that were mutually parallel and had been optically polished was employed to measure the spectral transmittance over the wavelength range from 280 nm to 700 nm. The spectral transmittance was obtained by directing light rays of intensity A perpendicularly with respect to one of the optically polished flat surfaces, measuring the intensity B of the light rays exiting the other flat surface, and calculating B/A. Accordingly, the spectral transmittance included the reflectance loss of the light rays at the sample surfaces. The wavelength at which the spectral transmittance became 70% was adopted as 70, and the wavelength at which the spectral transmittance became 5% was adopted as 5. The measurement results are given in Table 1.

(17) TABLE-US-00001 TABLE 1 No. P.sup.5+ B.sup.3+ Si.sup.4+ Li.sup.+ Na.sup.+ K.sup.+ Rb.sup.+ Cs.sup.+ Mg.sup.2+ Ca.sup.2+ Sr.sup.2+ Ba.sup.2+ Zn.sup.2+ La.sup.3+ 1 26.83 5.85 0.00 0.00 0.00 3.90 0.00 0.00 0.00 0.00 0.00 1.95 0.00 0.00 2 26.83 5.85 0.00 0.00 0.00 1.95 0.00 1.95 0.00 0.00 0.00 1.95 0.00 0.00 3 26.31 0.00 0.00 0.00 0.00 9.57 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4 26.56 0.00 0.00 0.00 0.00 8.70 0.00 0.00 0.00 0.00 0.00 0.97 0.00 0.00 5 26.83 0.00 0.00 0.00 0.00 5.85 0.00 0.00 0.00 0.00 0.00 3.90 0.00 0.00 6 26.58 0.00 0.00 0.00 0.00 5.80 0.00 0.00 0.00 0.00 0.00 3.86 0.00 0.00 7 26.57 0.00 0.00 0.00 7.73 0.00 0.00 0.00 0.00 0.00 0.00 1.93 0.00 0.00 8 26.59 0.00 0.00 0.00 6.76 1.93 0.00 0.00 0.00 0.00 0.00 1.93 0.00 0.00 9 27.64 0.00 0.00 0.00 4.02 2.01 0.00 0.00 0.00 0.00 0.00 2.01 0.00 0.00 10 26.90 0.00 0.00 0.00 1.71 1.71 0.00 0.00 0.00 0.00 0.00 4.40 0.00 0.00 11 27.10 2.96 0.00 0.00 0.49 0.00 0.00 0.00 0.00 0.00 0.00 4.43 0.00 0.00 12 27.09 2.96 0.00 0.00 0.00 0.49 0.00 0.00 0.00 0.00 0.00 4.43 0.00 0.00 13 26.81 2.93 0.00 0.00 0.00 0.00 0.00 2.93 0.00 0.00 0.00 1.95 0.00 0.00 14 26.45 2.88 0.00 0.00 0.48 0.00 0.00 0.00 0.00 0.00 0.00 4.33 0.00 0.00 No. Gd.sup.3+ Y.sup.3+ Yb.sup.3+ Zr.sup.4+ Ti.sup.4+ Nb.sup.5+ Ta.sup.5+ Bi.sup.3+ W.sup.6+ Te.sup.4+ Ge.sup.4+ Al.sup.3+ Total 1 0.00 0.00 0.00 0.00 9.76 18.54 0.00 21.46 11.71 0.00 0.00 0.00 100.00 2 0.00 0.00 0.00 0.00 9.76 18.54 0.00 21.46 11.71 0.00 0.00 0.00 100.00 3 0.00 0.00 0.00 0.00 9.57 16.27 0.00 22.97 15.31 0.00 0.00 0.00 100.00 4 0.00 0.00 0.00 0.00 0.66 17.39 0.00 23.19 13.53 0.00 0.00 0.00 100.00 5 0.00 0.00 0.00 0.00 9.76 17.56 0.00 22.44 13.66 0.00 0.00 0.00 100.00 6 0.00 0.00 0.00 0.00 11.59 17.39 0.00 23.19 11.59 0.00 0.00 0.00 100.00 7 0.00 0.00 0.00 0.00 9.66 17.39 0.00 23.19 13.53 0.00 0.00 0.00 100.00 8 0.00 0.00 0.00 0.00 9.66 17.39 0.00 24.15 11.59 0.00 0.00 0.00 100.00 9 0.00 0.00 0.00 0.00 10.05 18.09 0.00 24.12 12.06 0.00 0.00 0.00 100.00 10 0.00 0.00 0.00 0.00 10.02 18.58 0.00 25.43 11.25 0.00 0.00 0.00 100.00 11 0.00 0.00 0.00 0.00 10.34 19.21 0.00 26.60 8.87 0.00 0.00 0.00 100.00 12 0.00 0.00 0.00 0.00 10.34 18.23 0.00 27.59 8.87 0.00 0.00 0.00 100.00 13 0.00 0.00 0.00 0.00 9.76 18.54 0.00 25.37 11.71 0.00 0.00 0.00 100.00 14 0.00 0.00 0.00 0.00 8.17 18.27 0.00 25.96 13.46 0.00 0.00 0.00 100.00 (A) B.sup.3+ + Li.sup.+ + Na.sup.+ + K.sup.+ + (B) Glass Ti.sup.4+ + Rb.sup.+ + Cs.sup.+ + Ti.sup.4+ + Nb.sup.5+ + Li.sup.+ + Na.sup.+ + transition Nb.sup.5+ + W.sup.6+ + Ti.sup.4+ + W.sup.6+ + (Ti.sup.4+ + Nb.sup.5+)/ Mg.sup.2+ + Ca.sup.2+ + W.sup.6+ + Bi.sup.3+ + (A)/ K.sup.+ + Rb.sup.+ + temperature No. Bi.sup.3+ + Te.sup.4+ Nb.sup.5+ Bi.sup.3+ (W.sup.6+ + Bi.sup.3+) Sr.sup.2+ + Ba.sup.2+ Te.sup.4+ (B) Cs.sup.+ ( C.) 1 61.47 28.30 33.17 0.85 11.70 61.47 0.19 3.90 556 2 61.47 28.30 33.17 0.85 11.70 61.47 0.19 3.90 558 3 64.12 25.84 38.28 0.68 9.57 64.12 0.15 9.57 555 4 63.77 27.05 36.72 0.74 9.67 63.77 0.15 8.70 558 5 63.42 27.32 36.10 0.76 9.75 63.42 0.15 5.85 568 6 63.76 28.98 34.78 0.83 9.66 63.76 0.15 5.80 569 7 63.77 27.05 36.72 0.74 9.66 63.77 0.15 7.73 549 8 62.79 27.05 35.74 0.76 10.62 62.79 0.17 8.69 547 9 64.32 28.14 36.18 0.78 8.04 64.32 0.13 6.03 551 10 65.28 28.60 36.68 0.78 7.82 65.28 0.12 3.42 565 11 65.02 29.55 35.47 0.83 7.88 65.02 0.12 0.49 564 12 65.03 28.57 36.46 0.78 7.88 65.03 0.12 0.49 562 13 65.38 28.30 37.08 0.76 7.81 65.38 0.12 2.93 559 14 65.86 26.44 39.42 0.67 7.69 65.86 0.12 0.48 557 Temperature at which Viscosity glass exhibited at liquidus viscosity Liquidus temperature of 10 dPa .Math. s Specific 70 5 No. temperature ( C.) (dPs .Math. s) ( C.) gravity nd d (nm) (nm) 1 945 2.8 1030 5.26 2.061 17.4 490 421 2 945 2.8 1030 5.27 2.058 17.5 487 419 3 935 3.2 1020 5.39 2.067 16.9 502 424 4 925 3.8 1020 5.41 2.073 17.0 475 420 5 925 4.0 1025 5.44 2.070 17.3 487 422 6 965 2.0 1030 5.42 2.077 17.2 493 423 7 950 2.4 1025 5.50 2.088 17.0 484 418 8 960 2.0 1020 5.44 2.077 17.2 473 417 9 950 2.4 1025 5.46 2.082 17.1 477 417 10 945 3.0 1030 5.61 2.097 17.1 482 418 11 950 3.8 1040 5.59 2.102 17.3 493 422 12 950 3.8 1040 5.62 2.102 17.3 491 422 13 945 3.8 1045 5.54 2.088 17.1 496 421 14 945 4.0 1040 5.70 2.102 17.2 498 421

Example 2

(18) Glass starting materials were heated, melted, refined, and homogenized to obtain optical glass Nos. 1 to 14 in the same manner as in Example 1, and the glass melt obtained was caused to flow into a casting mold and quenched to mold into a glass block. Next, the glass block was annealed, cut, and ground to prepare a press molding glass material.

Example 3

(19) The glass materials for press molding that were prepared in Example 2 were heated, softened, and press molded by a known method using a pressing mold to prepare optical element blanks such as lens blanks and prism blanks.

(20) The optical element blanks obtained were precision annealed and the refractive indexes thereof were precisely adjusted to the desired refractive indexes. They were then finished into lenses and prisms by known grinding and polishing methods.

Example 4

(21) The surfaces of the press molding glass materials prepared in Example 2 were polished to prepare press molding glass materials for precision press molding. These glass materials were heated and precision press molded to obtain aspherical lenses. The precision press molding was conducted by a known method.

(22) Various optical elements such as lenses and prisms were prepared in this manner.

(23) When imaging optical systems were assembled with the lenses obtained in Examples 3 and 4, it was possible to obtain an imaging device with good color reproduction properties.

(24) When portable telephone-mounted imaging units and optical pickup units were prepared using the lenses obtained, units with extremely little focal position displacement caused by vibration could be obtained.

(25) The optical element of the present Example permits good correction of chromatic aberration when combined with an optical element of low dispersion glass. It is effective for high functionality and compactness to various optical devices, including imaging devices.

(26) An aspect of the present invention can provide optical glass having a high refractive index that is suitable as an optical element material for use in correcting chromatic aberration, and can provide a press molding glass material and an optical element employing the above optical glass.

(27) The implementation modes that have been disclosed herein are but examples in all regards and are not to be considered as limitations. The scope of the present invention is disclosed by the scope of the claims and not by the description given above. All modifications falling within the meaning and scope that are equivalent to the scope of the claims are intended to be covered.

(28) For example, optical glass according to an aspect of the present invention can be prepared by applying the compositional adjustment disclosed in the specification to the glass compositions exemplified above.

(29) In addition, any combination of two or more of the matters that have been described as an exemplified or desirable scope in the specification is, of course, possible.