JPWO2019142397A1 - Optical glass, optical elements using optical glass, optical devices - Google Patents

Abstract

Al3 + is 30 to 40% and P5 + is 1 to 15% in terms of molar% of cations, and O2- is 5 to 16% and F- is 84 to 95% in terms of molar% of anions. An optical glass having a ratio (O / P) of the number of oxygen atoms to the number of phosphorus atoms of less than 3.4.

Description

The present invention relates to optical glass, an optical element using optical glass, and an optical device. The present invention claims the priority of application number 2018-006394 of the Japanese patent filed on January 18, 2018, and for designated countries where incorporation by reference to the literature is permitted, the content described in the application is Incorporated into this application by reference.

Fluorite, which has a low refractive index and low dispersibility, is used as a lens material for optical systems in optical devices. Fluorite is produced, for example, by a crucible descent method (Bridgeman method) as shown in Patent Document 1.

Japanese Unexamined Patent Publication No. 2005-330156

The first aspect of the present invention is that Al ³⁺ is 30 to 40%, P ⁵⁺ is 1 to 15%, and O ² to 5 to 16 is expressed in molar% of anion. %, F ⁻ is 84 to 95%, and the ratio (O / P) of the number of oxygen atoms to the number of phosphorus atoms is less than 3.4.

The second aspect of the present invention is an optical element using the optical glass of the first aspect.

A third aspect of the present invention is an optical device including the optical element of the second aspect.

It is a perspective view of the image pickup apparatus which concerns on this embodiment. It is a block diagram which shows the example of the structure of the multiphoton microscope which concerns on this embodiment. It is a figure which plotted the λ ₈₀ value with respect to O / P of each Example and each comparative example.

Hereinafter, embodiments of the present invention (hereinafter, referred to as “the present embodiment”) will be described. The following embodiments are examples for explaining the present invention, and are not intended to limit the present invention to the following contents. The present invention can be appropriately modified and implemented within the scope of the gist thereof.

In the present specification, unless otherwise specified, the content of each component is indicated by the molar% representation of the cation and the molar% representation of the anion. The mol% of the cation and the mol% of the anion referred to here are those in which the total amount of the cation component and the total amount of the anion component contained in the glass are 100 mol%, respectively. It is assumed that all complex salts such as carbonates, hydroxides, nitrates, and hydrous salts used as raw materials for glass constituents are decomposed into oxides and / or fluorides at the time of melting. The gas component generated by the decomposition of the composite salt is not considered as a glass component.

The optical glass according to the present embodiment has Al ³⁺ of 30 to 40% and P ⁵⁺ of 1 to 15% in molar% of cations, and O ² to 5 to 16 in molar% of anions. %, F ⁻ is 84 to 95%, and the ratio (O / P) of the number of oxygen atoms to the number of phosphorus atoms is less than 3.4. According to the present embodiment, it is possible to obtain an optical glass having a low refractive index and a low dispersion optical constant and good ultraviolet and visible light transmittance in the fluorinated optical glass.

For example, fluorite is produced by the Bridgman method, but there is a problem that it is not suitable for mass production because the amount that can be produced at one time is limited and it takes time. Further, since fluorite has cleavability, it has a problem that it has poor mechanical strength and is difficult to process. Regarding these points, the optical glass according to the present embodiment has a low refractive index and low dispersibility equivalent to that of fluorite, and can solve the above-mentioned problems of fluorite.

(Cation component)
Al ³⁺ has the effect of improving the devitrification resistance of optical glass. If the content is low, the optical glass is likely to be devitrified, but even if it is introduced excessively, the optical glass is likely to be devitrified. From this point of view, the content of Al ³⁺ is 30 to 40%, preferably 32 to 38%, and more preferably 34 to 37%.

P ⁵⁺ has the effect of improving the devitrification resistance of the optical glass. If the content is low, the optical glass tends to be devitrified, but if it is introduced excessively, the dispersion becomes too large. From this point of view, the content of P ⁵⁺ is 1 to 15%, preferably 3 to 12%, and more preferably 5 to 10%.

In the present embodiment, for example, components such as Li ⁺ , Na ⁺ , K ⁺ , Mg ²⁺ , Ca ²⁺ , Sr ²⁺ , Ba ²⁺ , Zn ²⁺ , Y ³⁺ , La ³⁺ , Gd ³⁺ , and Zr ⁴⁺ are appropriately contained. Can be done.

Li ⁺ has the effect of increasing the meltability of optical glass, but if it is introduced excessively, the devitrification resistance will decrease, and the viscosity of the glass during molding will decrease, making it difficult to form the glass. is there. From this point of view, the Li ⁺ content is preferably 0 to 3%, more preferably 0 to 2%, and even more preferably 0 to 1%.

Na ⁺ has the effect of increasing the meltability of optical glass, but if it is introduced in excess, the devitrification resistance will decrease, and the viscosity of the glass during molding will decrease, making it difficult to form the glass. is there. From this point of view, the content of Na ⁺ is preferably 0 to 3%, more preferably 0 to 2%, still more preferably 0 to 1%.

K ⁺ has the effect of increasing the meltability of optical glass, but if it is introduced excessively, the devitrification resistance will decrease, and the viscosity of the glass during molding will decrease, making it difficult to form the glass. is there. From this point of view, the content of K ⁺ is preferably 0 to 2%, more preferably 0 to 1.5%, and even more preferably 0 to 1%.

Mg ²⁺ has the effect of improving the devitrification resistance of optical glass. If the content is too small, the effect of improving the devitrification resistance cannot be sufficiently obtained. Further, if it is introduced excessively, the refractive index tends to decrease, and the devitrification resistance tends to decrease. From this point of view, the content of Mg ²⁺ is preferably 5 to 10%, more preferably 6 to 9%, still more preferably 7 to 8%.

Ca ²⁺ has the effect of improving the devitrification resistance of optical glass. If the content is too small, the effect of improving the devitrification resistance cannot be sufficiently obtained. Further, if it is introduced excessively, the refractive index tends to decrease, and the devitrification resistance tends to decrease. From this point of view, the content of Ca ²⁺ is preferably 20 to 30%, more preferably 22 to 28%, and even more preferably 23 to 25%.

Sr ²⁺ has the effect of increasing the refractive index of the optical glass and improving the devitrification resistance. If the content is too small, the effect of increasing the refractive index and the effect of improving the devitrification resistance cannot be sufficiently obtained. In addition, if it is introduced excessively, the dispersibility becomes too large, and the devitrification resistance tends to decrease. From this point of view, the content of Sr ²⁺ is preferably 10 to 20%, more preferably 12 to 18%, and even more preferably 14 to 17%.

Ba ²⁺ has the effect of increasing the refractive index of the optical glass and improving the devitrification resistance. If the content is too small, the effect of increasing the refractive index and the effect of improving the devitrification resistance cannot be sufficiently obtained. In addition, if it is introduced excessively, the dispersibility becomes too large, and the devitrification resistance tends to decrease. From this point of view, the content of Ba ²⁺ is preferably 3 to 10%, more preferably 4 to 9%, still more preferably 5 to 8%.

Zn ²⁺ has the effect of improving the devitrification resistance of the optical glass. However, if it is introduced excessively, the dispersibility tends to be too large. From this point of view, the content of Zn ²⁺ is preferably 0 to 3%, more preferably 0 to 2%, and even more preferably 0 to 1%.

Y ³⁺ has the effect of increasing the refractive index while maintaining the low dispersibility of the optical glass, maintaining the meltability of the raw material, suppressing the rise in the liquidus temperature, and improving the devitrification resistance of the optical glass. However, if it is introduced excessively, the meltability of the glass raw material deteriorates, and the liquidus temperature tends to rise to lower the devitrification resistance of the glass. From this point of view, the content of Y ³⁺ is preferably 0 to 5%, more preferably 0 to 3%, still more preferably 0 to 2%, still more preferably 0 to 1%. ..

La ³⁺ has the effect of increasing the refractive index while maintaining the low dispersibility of the optical glass, maintaining the meltability of the raw material, suppressing the rise in the liquidus temperature, and improving the devitrification resistance of the optical glass. However, if it is introduced excessively, the meltability of the glass raw material deteriorates, and the liquidus temperature tends to rise to lower the devitrification resistance of the glass. From this point of view, the content of La ³⁺ is preferably 0 to 5%, more preferably 0 to 3%, further preferably 0 to 2%, still more preferably 0 to 1%. ..

Gd ³⁺ has the effect of increasing the refractive index while maintaining the low dispersibility of the optical glass, maintaining the meltability of the raw material, suppressing the rise in the liquidus temperature, and improving the devitrification resistance of the optical glass. However, if it is introduced excessively, the meltability of the glass raw material deteriorates, and the liquidus temperature tends to rise to lower the devitrification resistance of the glass. From this point of view, the content of Gd ³⁺ is preferably 0 to 5%, more preferably 0 to 3%, further preferably 0 to 2%, and even more preferably 0 to 1%. ..

Zr ⁴⁺ has the effect of increasing the refractive index of the optical glass, suppressing dispersion, and improving devitrification resistance. However, if it is introduced excessively, the dispersibility becomes too large, and the devitrification resistance tends to decrease. From this point of view, the content of Zr ⁴⁺ is preferably 0 to 1%.

Suitable combinations of contents for the above-mentioned components are Mg ²⁺ of 5 to 10%, Ca ²⁺ of 20 to 30%, Sr ²⁺ of 10 to 20%, and Ba ²⁺ of 3 to 10%. Further, Li ⁺ is 0 to 3%, Na ⁺ is 0 to 3%, K ⁺ is 0 to 2%, and Zn ²⁺ is 0 to 3%. Further, Y ³⁺ is 0 to 5%, La ³⁺ is 0 to 5%, Gd ³⁺ is 0 to 5%, and Zr ⁴⁺ is 0 to 1%.

(Anion component)
An anion component O ^2- and F ^- is the refractive index of the optical glass, the dispersibility and contributes to stability. From the viewpoint of dispersion and refractive index of the optical glass, ^{O 2-in} mol% of the anion is from 5 to 16%, preferably 7-14%, more preferably 9 to 12%. From the viewpoint of dispersion and refractive index of the optical glass, F ⁻ is 84 to 95%, preferably 86 to 93%, and more preferably 88 to 91% in terms of molar% of anions.

If the ratio (O / P) of the number of oxygen atoms to the number of phosphorus atoms is less than 3.4, good ultraviolet transmittance can be maintained, but if it is 3.4 or more, the internal transmittance becomes 80%. The wavelength (λ ₈₀ ) shifts to the longer wavelength side, and the light transmittance in the ultraviolet region deteriorates. From this point of view, the O / P is less than 3.4, preferably 3.2 or less, and more preferably 3.0 or less. The ratio (O / P) of the number of oxygen atoms to the number of phosphorus atoms has the same meaning as the ratio of oxygen (O) to phosphorus (P) in the atomic% (at.%) Display.

Not limited to the above components, other components may be added as long as the effect of the optical glass according to the present embodiment can be obtained.

The method for producing the optical glass according to the present embodiment is not particularly limited, and a known method can be adopted. Further, as the production conditions, suitable conditions can be appropriately selected. For example, raw materials such as oxides and fluorides are blended so as to have a target composition, preferably melted at 850 to 1150 ° C., more preferably 950 to 1050 ° C., and stirred to homogenize and break bubbles. After that, a manufacturing method or the like of casting and molding in a mold can be adopted. The optical glass thus obtained can be made into a desired optical element by performing reheat pressing or the like as necessary to process it into a desired shape and polishing or the like.

Next, the physical property values of the optical glass according to the present embodiment will be described.

The optical glass according to this embodiment has a low refractive index and a low dispersion (a large Abbe number (ν _d )). The Abbe number (ν _d ) of the optical glass according to the present embodiment is preferably 92 to 97, more preferably 93 to 97, and even more preferably 94 to 97. The refractive index of the optical glass according to the present embodiment _{(n d)} is preferably from 1.41 to 1.45, more preferably 1.42 to 1.45, more preferably 1.43～ It is 1.45. The preferred combination as the physical properties of the optical glass according to this embodiment, refractive index _{(n d)} is in the range of 1.41 to 1.45, and the range Abbe number ([nu _d) is 92-97 It is in.

From the viewpoint of the ultraviolet and visible light transmittance of the optical system, the wavelength (λ ₈₀ ) at which the internal transmittance is 80% at an optical path length of 10 mm in the optical glass according to the present embodiment is preferably 340 nm or less, more preferably. Is 338 nm or less, more preferably 336 nm or less.

Further, in the optical glass according to the present embodiment, the wavelength (λ ₅ ) at which the internal transmittance is 5% at an optical path length of 10 mm is preferably 300 nm or less, more preferably 298 nm or less, and further preferably 296 nm or less. Is.

From the above viewpoint, the optical glass according to the present embodiment can be suitably used as, for example, an optical element included in an optical device. As an optical device, it is particularly suitable as an imaging device or a multiphoton microscope.

<Imaging device>
FIG. 1 shows an image pickup apparatus 1 (optical device) provided with a lens 103 (optical element) using the optical glass as a base material according to the present embodiment. The image pickup device 1 is a so-called digital single-lens reflex camera, and a lens barrel 102 is detachably attached to a lens mount (not shown) of the camera body 101. Then, the light that has passed through the lens 103 of the lens barrel 102 is imaged on the sensor chip (solid-state image sensor) 104 of the multi-chip module 106 arranged on the back side of the camera body 101. The sensor chip 104 is a bare chip such as a so-called CMOS image sensor, and the multi-chip module 106 is a COG (Chip On Glass) type module in which, for example, the sensor chip 104 is bare chip mounted on a glass substrate 105.

The optical system used in such a digital camera or the like is required to have higher resolution, lighter weight, and smaller size. In order to realize these, it is effective to use optical glass having a high refractive index for the optical system. From this point of view, the optical glass according to the present embodiment is suitable as a member of such an optical device. The optical device applicable to this embodiment is not limited to the above-mentioned imaging device, and examples thereof include a projector and the like. The optical element is not limited to a lens, and examples thereof include a prism and the like.

<Multiphoton microscope>
FIG. 2 is a block diagram showing an example of the configuration of the multiphoton microscope 2 according to the present embodiment. The multiphoton microscope 2 includes an objective lens 206, a condenser lens 208, and an imaging lens 210 as optical elements. Hereinafter, the optical system of the multiphoton microscope 2 will be mainly described.

The pulse laser apparatus 201 emits ultrashort pulsed light having a near infrared wavelength (about 1000 nm) and a pulse width in femtosecond units (for example, 100 femtoseconds). The ultrashort pulsed light immediately after being emitted from the pulse laser device 201 is generally linearly polarized light polarized in a predetermined direction.

The pulse dividing device 202 divides the ultrashort pulsed light and emits the ultrashort pulsed light at a high repetition frequency.

The beam adjusting unit 203 has a function of adjusting the beam diameter of the ultrashort pulsed light incident from the pulse dividing device 202 according to the pupil diameter of the objective lens 206, and the wavelength and ultrashort of the multiphoton excitation light emitted from the sample S. A function to adjust the focusing and divergence angle of ultrashort pulsed light to correct axial chromatic aberration (focus difference) with the wavelength of pulsed light, and a group while the pulse width of ultrashort pulsed light passes through the optical system. It has a pre-charp function (group velocity dispersion compensation function) that gives the ultra-short pulsed light the opposite group velocity dispersion in order to correct the spread due to the velocity dispersion.

The repetition frequency of the ultrashort pulsed light emitted from the pulse laser device 201 is increased by the pulse dividing device 202, and the above adjustment is performed by the beam adjusting unit 203. Then, the ultrashort pulsed light emitted from the beam adjusting unit 203 is reflected by the dichroic mirror 204 in the direction of the dichroic mirror 205, passes through the dichroic mirror 205, is collected by the objective lens 206, and is irradiated to the sample S. .. At this time, by using a scanning means (not shown), the ultrashort pulsed light may be scanned on the observation surface of the sample S.

For example, when observing the sample S by fluorescence, the fluorescent dye in which the sample S is stained is multiphoton excited in the irradiated region of the ultrashort pulse light of the sample S and its vicinity, and the ultrashort wavelength is an infrared wavelength. Fluorescence (hereinafter referred to as "observation light") having a shorter wavelength than pulsed light is emitted.

The observation light emitted from the sample S in the direction of the objective lens 206 is collimated by the objective lens 206 and reflected by the dichroic mirror 205 or transmitted through the dichroic mirror 205 depending on the wavelength thereof.

The observation light reflected by the dichroic mirror 205 is incident on the fluorescence detection unit 207. The fluorescence detection unit 207 is composed of, for example, a barrier filter, a PMT (photomultiplier tube) or the like, receives observation light reflected by the dichroic mirror 205, and outputs an electric signal according to the amount of the light. .. Further, the fluorescence detection unit 207 detects the observation light over the observation surface of the sample S as the ultrashort pulse light is scanned on the observation surface of the sample S.

On the other hand, the observation light transmitted through the dichroic mirror 205 is descanned by scanning means (not shown), transmitted through the dichroic mirror 204, collected by the condenser lens 208, and placed at a position substantially conjugate with the focal position of the objective lens 206. It passes through the provided pinhole 209, passes through the imaging lens 210, and enters the fluorescence detection unit 211.

The fluorescence detection unit 211 is composed of, for example, a barrier filter, a PMT, or the like, receives the observation light imaged on the light receiving surface of the fluorescence detection unit 211 by the imaging lens 210, and outputs an electric signal according to the amount of the light. Further, the fluorescence detection unit 211 detects the observation light over the observation surface of the sample S as the ultrashort pulse light is scanned on the observation surface of the sample S.

By removing the dichroic mirror 205 from the optical path, the fluorescence detection unit 211 may detect all the observation light emitted from the sample S in the direction of the objective lens 206.

Further, the observation light emitted from the sample S in the direction opposite to that of the objective lens 206 is reflected by the dichroic mirror 212 and incident on the fluorescence detection unit 213. The fluorescence detection unit 213 is composed of, for example, a barrier filter, a PMT, or the like, receives the observation light reflected by the dichroic mirror 212, and outputs an electric signal according to the amount of the light. Further, the fluorescence detection unit 213 detects the observation light over the observation surface of the sample S as the ultrashort pulse light is scanned on the observation surface of the sample S.

The electric signals output from the fluorescence detection units 207, 211, and 213 are input to, for example, a computer (not shown), and the computer generates an observation image based on the input electric signals, and the generated observation. Images can be displayed and observation image data can be stored.

Examples and comparative examples of the present invention will be described. Each table shows the composition of the optical glass according to the examples and the comparative examples, the refractive index ( _nd ), the Abbe number (ν _d ), the wavelength (λ ₈₀ ) at which the internal transmittance is 80% at the optical path length of 10 mm, and It is shown together with the measurement result of the wavelength (λ ₅ ) at which the internal transmittance is 5% at an optical path length of 10 mm. The present invention is not limited to these examples.

<Making optical glass>
The optical glass according to each Example and Comparative Example was produced by the following procedure. First, optical glass raw materials such as oxides, phosphates and fluorides were weighed so that the optical glass weight was 100 g so as to have the chemical composition (% by weight) shown in each table. Next, the weighed raw materials were mixed and put into a platinum crucible, melted at a temperature of 950 ° C. for about 1 hour, and homogenized by stirring. Then, after lowering the temperature, it was cast into a mold or the like and slowly cooled to obtain each sample.

<Measurement of optical glass>
1. 1. Refractive index ( _nd ) and Abbe number (ν _d )
The refractive index ( _nd ) and Abbe number (ν _d ) of each sample were measured and calculated using a refractive index measuring device (manufactured by Shimadzu Corporation; “KPR-2000”). n _d represents the refractive index of optical glass to light of 587.562 nm. ν _d was obtained from the following equation (1). n _C and n _F indicate the refractive indexes of the optical glass with respect to light having wavelengths of 656.273 nm and 486.133 nm, respectively. The value of the refractive index was up to the fifth decimal place.
ν _d = (n _d -1) / (n _F −n _C ) ・ ・ ・ (1)

2. 2. Wavelength with internal transmittance of 80% (λ ₈₀ ) and wavelength with internal transmittance of 5% (λ ₅ )
Optically polished optical glass samples having a thickness of 12 mm and a thickness of 2 mm were prepared, and the internal transmittance in the wavelength range of 200 to 700 nm when light was incident parallel to the thickness direction was measured. Then, the wavelength at which the internal transmittance is 80% at an optical path length of 10 mm is defined as λ _80, and the wavelength at which the internal transmittance is 5% is defined as λ ₅ .

The results of each example and comparative example are shown in each table, and FIG. 3 shows a plot of λ ₈₀ values for O / P. Unless otherwise specified, the composition values in the table are shown in mol% of cation for the cation component and in mol% of anion for the anion component. Further, "devitrification" in the table indicates that devitrification occurred when the optical glass was manufactured, and measurement (that is, use as the optical glass) was impossible.

It was confirmed that each of the examples had a low refractive index and a low dispersion, and had a good transmittance.

1 ... Imaging device, 101 ... Camera body, 102 ... Lens barrel, 103 ... Lens, 104 ... Sensor chip, 105 ... Glass substrate, 106 ... Multi-chip module, 2 ... Multiphoton microscope, 201 ... Pulse laser device, 202 ... Pulse splitting device, 203 ... Beam adjustment unit, 204, 205, 212 ... Dicroic mirror, 206 ... Objective lens, 207, 211,213 ... Fluorescence detector, 208 ... Condensing lens, 209 ... Pinhole, 210 ... Imaging lens, S ... Sample

The first aspect of the present invention is the molar% representation of cations, where the Al ³⁺ content is 30-40%, the P ⁵⁺ content is 1-15% , and the La ³⁺ content is 0.83-5%. , The content of Mg ²⁺ is 5 to 8.16% , and the content of O ^2- is 5 to 16% and the content of F ⁻ is 84 to 95% in terms of molar% of anions. Moreover, it is an optical glass in which the ratio (O / P) of the number of oxygen atoms to the number of phosphorus atoms is 3.1 or more and less than 3.4.
The second aspect of the present invention is the molar% representation of the cation, in which the Al ³⁺ content is 30 to 40%, the P ⁵⁺ content is 1 to 15%, and the La ³⁺ content is 0.83 to 0.83. The content of 5%, Ba ²⁺ is 3 to 7.35%, and the content of O ^2- is 5 to 16% and the content of F ⁻ is 84 to 95% in terms of molar% of anions. It is an optical glass in which the ratio (O / P) of the number of oxygen atoms to the number of phosphorus atoms is 3.1 or more and less than 3.4.

A third aspect of the present invention is an optical element using the optical glass of the first or second aspect .

A fourth aspect of the present invention is an optical device including the optical element of the third aspect.

Claims (10)

In molar% representation of cations
Al ³⁺ is 30-40%,
P ⁵⁺ is 1 to 15% and
In molar% indication of anion,
O ^2- is 5 to 16%,
F ^- is 84-95% and
An optical glass characterized in that the ratio (O / P) of the number of oxygen atoms to the number of phosphorus atoms is less than 3.4. In molar% representation of cations
Mg ²⁺ is 5-10%,
Ca ²⁺ is 20-30%,
Sr ²⁺ is 10 to 20%,
The optical glass according to claim 1, wherein Ba ²⁺ is 3 to 10%. In molar% representation of cations
Li ⁺ is 0 to 3%,
Na ⁺ is 0 to 3%,
K ⁺ is 0 to 2%,
The optical glass according to claim 1 or 2, wherein Zn ²⁺ is 0 to 3%. In molar% representation of cations
Y ³⁺ is 0-5%,
La ³⁺ is 0-5%,
Gd ³⁺ is 0-5%,
The optical glass according to any one of claims 1 to 3, wherein Zr ⁴⁺ is 0 to 1%. Refractive index _{(n d),} characterized in that in the range of 1.41 to 1.45, the optical glass according to any one of claims 1 to 4. The optical glass according to any one of claims 1 to 5, wherein the Abbe number (ν _d ) is in the range of 92 to 97. The optical glass according to any one of claims 1 to 6, wherein the wavelength (λ ₈₀ ) at which the internal transmittance is 80% at an optical path length of 10 mm is 340 nm or less. The optical glass according to any one of claims 1 to 7, wherein the wavelength (λ ₅ ) at which the internal transmittance is 5% at an optical path length of 10 mm is 300 nm or less. An optical element using the optical glass according to any one of claims 1 to 8. An optical device comprising the optical element according to claim 9.

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