Optical glass, optical element, optical system, interchangeable lens, and optical apparatus

Abstract

The present invention relates to optical glasses, optical elements, optical systems, interchangeable lenses, and optical devices. The present invention provides an optical glass, wherein, in terms of cations, P 5+ component is 30 to 45%, Al 3+ component is 10 to 20%, Ba 2+ component is 20 to 40%, in terms of anions, O 2‑ component is 75 to 95%, F ‑ component is 5 to 25%.

Description

[0001] This application is a divisional application, which is the target application of Chinese national application number 201980100735.2, filed on August 6, 2019, entitled "Optical Glass, Optical Element, Optical System, Replacement Lens and Optical Device". Technical Field

[0002] This invention relates to optical glass, optical elements, optical systems, interchangeable lenses, and optical devices. Background Technology

[0003] In the development of digital cameras, the optical systems used in digital cameras, for example, employ optical glass with high refractive index and low dispersion disclosed in Patent Document 1.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2009-286670 Summary of the Invention

[0007] The first aspect of the present invention is an optical glass, wherein, in terms of cations, P 5+ The composition is 30-45%, Al 3+ The composition is 10-20%, Ba 2+ The composition is 20-40%, calculated as anion%, O 2- The composition is 75-95%, F - The composition is 5-25%.

[0008] A second aspect of the present invention is an optical element that uses the aforementioned optical glass.

[0009] The third aspect of the present invention is an optical system comprising the aforementioned optical elements.

[0010] The fourth aspect of the present invention is a replaceable lens, which includes the aforementioned optical system.

[0011] The fifth aspect of the present invention is an optical device that includes the aforementioned optical system. Attached Figure Description

[0012] Figure 1 This is a perspective view of a camera device equipped with an optical element using the optical glass of this embodiment.

[0013] Figure 2 This is a front view of another example of a camera device equipped with an optical element using the optical glass of this embodiment.

[0014] Figure 3 yes Figure 2Rear view of the camera device.

[0015] Figure 4 This is a block diagram illustrating an example configuration of a multiphoton microscope equipped with optical elements using the optical glass of this embodiment.

[0016] Figure 5 Abbe number (ν) for each embodiment and each comparative example d ) and partial dispersion ratio (P g,F The diagram is created by drawing a graph.

[0017] Symbol Explanation

[0018] 1…Camera device, 101…Camera body, 102…Lens barrel, 103…Lens, 104…Sensor chip, 105…Glass substrate, 106…Multi-chip module, 2…Multiphoton microscope, 201…Pulsed laser device, 202…Pulse splitting device, 203…Beam adjustment unit, 204, 205, 212…Dial separator, 206…Objective lens, 207, 211, 213…Fluorescence detection unit, 208…Condenser lens, 209…Pinhole, 210…Imaging lens, S…Sample, CAM…Camera device, WL…Photographic lens, EF…Auxiliary light emission unit, LM…Liquid crystal monitor, B1…Release button, B2…Function button. Detailed Implementation

[0019] Hereinafter, embodiments of the present invention (hereinafter referred to as "this embodiment") will be described. The following embodiments are illustrative examples for explaining the present invention and are not intended to limit the present invention to the following content.

[0020] In the optical glass of this embodiment, P is expressed as a cation percentage. 5+ The composition is 30-45%, Al 3+ The composition is 10-20%, Ba 2+ The composition is 20-40%, calculated as anion%, O 2- The composition is 75-95%, F - The composition is 5-25%.

[0021] Unless otherwise stated, the proportions of each component in this specification are based on molar ratios as cations or anions.

[0022] The optical glass of this embodiment exhibits high refractive index, low dispersion, and high anomalous dispersion. Furthermore, the optical glass of this embodiment possesses excellent properties even without expensive components, thus enabling low-cost production. In addition, the optical glass of this embodiment not only has excellent optical constants but also suppresses the generation of internal glass ripples and exhibits high devitrification resistance.

[0023] Furthermore, as a preferred embodiment, it is possible to manufacture optical glass that maintains a high refractive index while possessing high anomalous dispersion. For example, existing optical glasses with anomalous dispersion cannot increase the refractive index, resulting in difficulties in simultaneously achieving refractive power (refractive index) and chromatic aberration correction capability when used in convex lenses, etc. The optical glass of this embodiment solves this problem and can be applied to a wide range of uses, fully meeting practical requirements.

[0024] Generally, if the Abbe number of an optical glass is large (low dispersion), the refractive index becomes small. In view of the above, "high refractive index" in this embodiment also includes cases where the refractive index is relatively high compared to ordinary optical glass with the same Abbe number, and does not only mean that the absolute value of the refractive index is large.

[0025] (Catonic component)

[0026] P 5+ It is a component that forms the glass framework and improves devitrification resistance. If P 5+ If the content of P is too low, it tends to have reduced resistance to devitrification; if P 5+ Excessive P content tends to decrease the refractive index. From this perspective, P... 5+ The content is 30-45%. Furthermore, the upper limit is preferably 41%, more preferably 40%. The lower limit is preferably 37%, more preferably 39%.

[0027] It should be noted that B 3+ B is also commonly used as a component in forming the glass framework, but in the optical glass of this embodiment, B 3+ With F - The reaction produces volatile substances such as BF3, which can sometimes lead to a decrease in the quality of optical glass. Therefore, in the optical glass of this embodiment, it is preferable to reduce the amount of BF3. 3+ The content of B is more preferably substantially free of B. 3+ .

[0028] In this specification, "substantially not present" means that the component is not present in a concentration exceeding that unavoidably present as an impurity and does not affect the properties of the glass composition. For example, if the content is around 100 ppm, it is considered substantially not present.

[0029] Al 3+ It is a component that improves devitrification resistance and achieves low dispersion. If Al 3+ If the content of Al is too low, it tends to have poor dispersion; if Al 3+ If the content is too high, it will have the effect described later: ΔP g,F The value tends to decrease. From this perspective, Al 3+The content is 10-20%. Furthermore, the upper limit is preferably 18%, more preferably 16%. The lower limit is preferably 12%, more preferably 14%.

[0030] Ba 2+ Is it maintaining ΔP g,F The value increases the refractive index of the component. If Ba 2+ If the content of Ba is too low, it tends to decrease the refractive index; if Ba... 2+ Excessive content of Ba tends to reduce resistance to devitrification. From this perspective, Ba... 2+ The content is 20-40%. Furthermore, the upper limit is preferably 36%, more preferably 32%. The lower limit is preferably 24%, more preferably 28%.

[0031] The optical glass in this embodiment may further contain the following components as needed.

[0032] Li + Is it to increase ΔP g,F The value and refractive index, as well as components that improve the meltability of glass. However, if Li... + Excessive content of [specific element] tends to reduce resistance to devitrification. Based on this, Li [specific element]... + The content is preferably 0-6%. Furthermore, the upper limit is more preferably 4%, and even more preferably 3%. The lower limit is more preferably 1%, and even more preferably 2%.

[0033] Na + and K + Sodium can be used as a component to improve the meltability of glass, but it can sometimes significantly reduce the refractive index. Therefore, in the optical glass of this embodiment, it is preferable that it is substantially free of sodium. + K + Of course, these components can also be included if there is a particular desire to improve the melting properties of the glass.

[0034] Mg 2+ Is it maintaining ΔP g,F The value increases the refractive index of the component. However, if Mg 2+ Excessive Mg content tends to reduce resistance to devitrification. From this perspective, Mg... 2+ The content is preferably 0-15%. Furthermore, the upper limit is more preferably 12%, and even more preferably 8%. The lower limit is more preferably 3%, and even more preferably 4%.

[0035] Ca 2+ Is it maintaining ΔP g,F The value increases the refractive index of the component. However, if Ca... 2+ Excessive Ca content tends to reduce resistance to devitrification. From this perspective, Ca... 2+The content is preferably 0-20%. Furthermore, the upper limit is more preferably 10%, and even more preferably 6%. The lower limit is more preferably 2%, and even more preferably 3%.

[0036] Sr 2+ Is it maintaining ΔP g,F The value increases the refractive index component. However, if Sr 2+ Excessive Sr content tends to reduce devitrification resistance. From this perspective, Sr... 2+ The content is preferably 0-20%. Furthermore, the upper limit is more preferably 10%, and even more preferably 6%. The lower limit is more preferably 2%, and even more preferably 3%.

[0037] Zn 2+ It is a component that increases both the refractive index and the meltability of the glass. However, if Zn 2+ Excessive Zn content tends to impair dispersion. From this perspective, Zn... 2+ The content is preferably 0-15%. Furthermore, the upper limit is more preferably 8%, and even more preferably 4%. The lower limit is more preferably 1%, and even more preferably 2%.

[0038] Y 3+ It is a component that increases the refractive index. However, if Y 3+ Excessive content of Y tends to reduce resistance to devitrification. From this perspective, Y... 3+ The content is preferably 0-6%. Furthermore, the upper limit is more preferably 4%, and even more preferably 2%. The lower limit is more preferably 0.5%, and even more preferably 1%.

[0039] La 3+ It is a component that increases the refractive index. However, if La... 3+ Excessive content of certain components tends to reduce resistance to devitrification. Based on this, La... 3+ The content is preferably 0-6%. Furthermore, the upper limit is more preferably 4%, and even more preferably 2%. The lower limit is more preferably 0.5%, and even more preferably 1%.

[0040] Gd 3+ It is a component that increases the refractive index. However, if Gd 3+ Excessive Gd content tends to reduce devitrification resistance. From this perspective, Gd... 3+ The content is preferably 0-6%. Furthermore, the upper limit is more preferably 4%, and even more preferably 2%. The lower limit is more preferably 0.5%, and even more preferably 1%.

[0041] Ti 4+ Is it maintaining ΔP g,F The value increases the refractive index of the component. However, if Ti 4+Excessive Ti content tends to impair dispersion. From this perspective, Ti... 4+ The content is preferably 0-6%. Furthermore, the upper limit is more preferably 4.5%, and even more preferably 3%. The lower limit is more preferably 0.5%, and even more preferably 1%.

[0042] Zr 4+ Is it maintaining ΔP g,F The value of Zr increases the refractive index of the component. However, if Zr 4+ Excessive Zr content tends to impair dispersion. From this perspective, Zr... 4+ The content is preferably 0 to 3%. Furthermore, the upper limit is more preferably 2%, and even more preferably 1%. The lower limit is more preferably 0.5%.

[0043] Nb 5+ Is it maintaining ΔP g,F The value increases the refractive index of the component. However, if Nb 5+ Excessive Nb content tends to impair dispersion. From this perspective, Nb... 5+ The content is preferably 0-8%. Furthermore, the upper limit is more preferably 6%, and even more preferably 4%. The lower limit is more preferably 1%, and even more preferably 2%.

[0044] Ta 5+ Is it maintaining ΔP g,F The value increases the refractive index of the component. However, if Ta 5+ Excessive content of certain substances tends to impair dispersion. From this perspective, Ta... 5+ The content is preferably 0 to 4%. Furthermore, the upper limit is more preferably 3%, and even more preferably 2%. The lower limit is more preferably 0.5%, and even more preferably 1%.

[0045] However, Ta 5+ Ta is an expensive raw material, so it is desirable to reduce its content. Therefore, with cost reduction as a priority, the optical glass of this embodiment preferably does not contain substantially Ta. 5+ Thus, the optical glass of this embodiment does not contain Ta, which is an expensive raw material. 5+ It also exhibits excellent physical properties, and therefore is also excellent in terms of cost.

[0046] In addition, from a cost perspective, the optical glass in this embodiment preferably does not contain Ge. 4+ Te 4 + .

[0047] W 6+ Is it maintaining ΔP g,F The value increases the refractive index of the component. However, if W6+ Excessive content of W tends to impair dispersion. From this perspective, W... 6+ The content is preferably 0-6%. Furthermore, the upper limit is more preferably 4%, and even more preferably 2%. The lower limit is more preferably 0.5%, and even more preferably 1%.

[0048] Sb 3+ It is the ingredient that imparts the defoaming effect. Sb 3+ The content is preferably 0 to 1%. The upper limit is more preferably 0.5%, and even more preferably 0.2%. The lower limit is more preferably 0.1%.

[0049] From the perspective of further improving the physical properties of the optical glass of this embodiment, it is preferable to include glass selected from Li + Components, Mg 2+ Ingredients, Ca 2+ Ingredients, Sr 2+ Ingredients, Zn 2+ Ingredients, Y 3+ Ingredients,La 3+ Ingredients, Gd 3+ Ingredients, Ti 4+ Ingredients, Zr 4+ Ingredients, Nb 5+ Ingredients, Ta 5+ Ingredients and W 6+ One or more of the components in the group.

[0050] Furthermore, as a preferred combination of the aforementioned optional components, Li + Composition: 0-6%, Mg 2+ Ingredients: 0-15%, Ca 2+ Ingredients: 0-20%, Sr 2+ Ingredients: 0-20%, Zn 2+ Ingredients: 0~15%, Y 3+ Ingredients: 0~6%, La 3+ Ingredients: 0~6%, Gd 3+ Composition: 0-6%, Ti 4+ Ingredients: 0~6%, Zr 4+ Ingredients: 0~3%, Nb 5+ Ingredients: 0~8%, Ta 5+ Ingredients: 0~4%, W 6+ Composition: 0-6%. By combining such components, the physical properties of optical glass can be further improved.

[0051] Furthermore, the optical glass in this embodiment preferably meets the following conditions.

[0052] From the perspective of improving devitrification resistance and achieving high refractive index, P 5+Ingredients + Al 3+ The preferred content is 40-65%. Furthermore, the upper limit is more preferably 58%, and even more preferably 55%. The lower limit is more preferably 45%, and even more preferably 53%.

[0053] From the perspective of improving devitrification resistance and achieving high refractive index, Mg 2+ Ingredients + Ca 2+ Ingredients + Sr 2+ Ingredients+Ba 2+ Ingredients + Zn 2+ Ingredients (ΣAE 2+ The content is preferably 35% to 50%. Furthermore, the upper limit is more preferably 44%, and even more preferably 41%. The lower limit is more preferably 36%, and even more preferably 39%.

[0054] From the perspective of improving devitrification resistance and achieving high refractive index, Y 3+ Ingredients+La 3+ Ingredient+Gd 3+ Ingredients (ΣRE 3+ The preferred value is 0-6%. Furthermore, the upper limit is more preferably 5%, and even more preferably 3%. The lower limit is more preferably 0.5%, and even more preferably 1%.

[0055] To improve devitrification resistance, achieve high refractive index and high ΔP g,F From a value perspective, Ti 4+ Ingredients+Zr 4+ Ingredient+Nb 5+ Ingredients+Ta 5+ Ingredients+W 6+ Ingredients (ΣTM) n+ Preferably, it is greater than 0 and less than 10%. Furthermore, the upper limit is more preferably less than 5%, and even more preferably less than 4%. The lower limit is more preferably more than 0.5%, and even more preferably more than 1%.

[0056] To improve devitrification resistance, achieve high Abbe number and high ΔP g,F From the perspective of value, P 5+ Composition relative to Al 3+ The proportion of components (P) 5+ / Al 3+ The value is preferably 1.5 to 4.5. Furthermore, the upper limit is more preferably 4, and even more preferably 3. The lower limit is more preferably 2, and even more preferably 2.5.

[0057] To improve devitrification resistance, achieve high refractive index and high ΔP g,F From a value perspective, Ba 2+ Ingredients + Zn 2+ Composition relative to Mg 2+ Ingredients + Ca2+ Ingredients + Sr 2+ The proportion of components (Ba) 2+ +Zn 2+ ) / (Mg 2+ +Ca 2+ +Sr 2+ The value is preferably 0.5 to 10. Furthermore, the upper limit is more preferably 5, and even more preferably 3. The lower limit is more preferably 1, and even more preferably 2.

[0058] Achieving high refractive index and high ΔP while maintaining devitrification resistance. g,F From a value perspective, Li + Ingredients + Mg 2+ Ingredients + Ca 2+ Ingredients + Sr 2+ Ingredients+Ba 2+ Ingredients + Zn 2+ Ingredient+Y 3+ Ingredients+La 3+ Ingredient+Gd 3+ Ingredients + Ti 4+ Ingredients+Zr 4+ Ingredient+Nb 5+ Ingredients+Ta 5+ Ingredients+W 6+ Components relative to P 5+ Ingredients + Al 3+ The proportion of components ((Li) + +ΣAE 2+ +ΣRE 3+ +ΣTM n+ ) / (P 5+ +Al 3+ The value is preferably 0.7 to 1.3. Furthermore, the upper limit is more preferably 1.1, and even more preferably 0.9. The lower limit is more preferably 0.75, and even more preferably 0.8.

[0059] Achieving high refractive index and high ΔP g,F From a value perspective, expressed in atomic % (at%), Ti 4+ Ingredients+Zr 4+ Ingredient+Nb 5+ Ingredients+Ta 5+ Ingredients+W 6+ Ingredients (ΣTM) n+ (relative to F) - The proportion of components ((ΣTM) n+ ) / F - The value is preferably 0.05 to 0.35. Furthermore, the upper limit is more preferably 0.2, and even more preferably 0.12. The lower limit is more preferably 0.06, and even more preferably 0.08.

[0060] (Anionic component)

[0061] O - The content is 75% to 95%. Furthermore, the upper limit is preferably 90%, more preferably 86%. The lower limit is preferably 82%, more preferably 84%.

[0062] F - Is it to increase ΔP g,F The components of the value and the Abbe number. If F - If the content is too low, then ΔP g,F A decrease in the value indicates a tendency for impaired low dispersion; if F - Excessive content of F tends to decrease the refractive index. From this perspective, F - The content is 5-25%. Furthermore, the upper limit is preferably 18%, more preferably 16%. The lower limit is preferably 10%, more preferably 14%.

[0063] It should be noted that the optical glass of this embodiment may also contain anionic components other than those described above. When used as a fluorinated glass, it may contain only O. - and F - .

[0064] Of which, the one mentioned here contains only O - and F - The situation refers to: O - and F - Other than O, anionic components are not included as constituents that exceed the concentration unavoidably present as impurities and affect the properties of the glass composition. For example, if O - and F - If anionic components other than those specified are mixed in at a concentration of approximately 100 ppm, it is considered that the anionic component is not actually present.

[0065] Furthermore, in addition to this, known clarifying agents, coloring agents, defoaming agents, oxides, and other components can be added to the glass composition in appropriate amounts as needed for purposes such as clarification, coloring, decolorization, and fine-tuning of optical constants. Moreover, other components may be added within the range required to achieve the effects of the optical glass of this embodiment, without being limited to the aforementioned components.

[0066] Next, the physical properties of the optical glass of this embodiment will be explained.

[0067] From the perspective of reducing the thickness of the lens, the optical glass in this embodiment preferably has a high refractive index (refractive index (n)). d (Large). However, there is a general tendency for a higher refractive index to result in a lower Abbe number; therefore, the refractive index (n) of the optical glass in this embodiment is... d The preferred range is 1.60 to 1.70. Furthermore, the refractive index, Abbe number, and ΔP...g,F The value tends to easily fall into a trade-off relationship, therefore the upper limit of the refractive index is more preferably 1.67, and even more preferably 1.64. The lower limit is more preferably 1.61, and even more preferably 1.62.

[0068] From the perspective of lens aberration correction, the optical glass in this embodiment is preferably low dispersion (Abbe number (ν)). d However, there is a general tendency for a higher Abbe number to correspond to a lower refractive index; therefore, the Abbe number (ν) of the optical glass in this embodiment is relatively high. d The preferred value is in the range of 40 to 65. Furthermore, the refractive index, Abbe number, and ΔP... g,F The value tends to easily fall into a trade-off relationship, therefore the upper limit is more preferably 63, and even more preferably 61. The lower limit is more preferably 50, and even more preferably 58.

[0069] The partial dispersion ratio (P) of the optical glass in this embodiment g,F The preferred value is 0.550 to 0.570. Furthermore, the upper limit is more preferably 0.562, and even more preferably 0.558. The lower limit is more preferably 0.552, and even more preferably 0.554.

[0070] ΔP of the optical glass in this embodiment g,F The preferred values ​​are 0.005 to 0.015. Furthermore, the refractive index, Abbe number, and ΔP... g,F The value tends to easily fall into a trade-off relationship, therefore the upper limit is more preferably 0.013, and even more preferably 0.011. The lower limit is more preferably 0.007, and even more preferably 0.009. The ΔP g,F The value becomes an indicator of anomalous dispersion.

[0071] The specific gravity (S) of the optical glass in this embodiment g The preferred value is 3.90 to 4.20. The upper limit is more preferably 4.15, and even more preferably 4.10. The lower limit is more preferably 3.95, and even more preferably 4.00.

[0072] The glass transition temperature (T) of the optical glass in this embodiment g Preferably, the temperature is 650°C or below. More preferably, it is 620°C, and even more preferably 600°C. By setting this glass transition temperature, moldability can be improved.

[0073] The manufacturing method of the optical glass in this embodiment is not particularly limited, and known methods can be used. Furthermore, the manufacturing conditions can be appropriately selected. As a preferred example, a method including the following steps can be described: selecting one of the following as a glass raw material: oxides, hydroxides, phosphoric acid compounds (phosphates, orthophosphoric acid, etc.), carbonates, sulfates, fluorides, and nitrates corresponding to the aforementioned raw materials; mixing them; melting and homogenizing them at a temperature of 1100–1400°C; and then cooling and shaping them.

[0074] More specifically, the manufacturing method can be as follows: raw materials such as oxides, hydroxides, phosphoric acid compounds (phosphates, orthophosphoric acid, etc.), carbonates, sulfates, fluorides, and nitrates are prepared in a manner that achieves the target composition. These materials are preferably melted and stirred at 1100–1400°C, more preferably 1100–1300°C, and even more preferably 1100–1250°C to homogenize them. After defoaming, the mixture is poured into a mold to form the desired shape. The resulting optical glass can then be re-hot-pressed or otherwise processed into the desired shape, and then ground to obtain the desired optical glass or optical element.

[0075] As explained above, the optical glass of this embodiment has high refractive index, low dispersion, and high anomalous dispersion, making it suitable as an optical element such as a lens in optical devices such as cameras and microscopes. Such optical elements include mirrors, lenses, prisms, and filters. Examples of optical systems incorporating these optical elements include objective lenses, condenser lenses, imaging lenses, and interchangeable lenses, making them particularly suitable for use as interchangeable lenses for cameras. Furthermore, these optical systems can be used in camera devices such as interchangeable-lens cameras and non-interchangeable-lens cameras, and microscopes such as multiphoton microscopes. It should be noted that the optical devices are not limited to the aforementioned camera devices and microscopes, but also include video cameras, teleconverters, telescopes, binoculars, monoculars, laser rangefinders, projectors, etc. When the optical glass of this embodiment is used for such applications, chromatic aberration can be reduced and the refractive power as a convex lens can be obtained. One example will be described below.

[0076] <Camera Device>

[0077] Figure 1 This is a perspective view of a camera device equipped with an optical element using the optical glass of this embodiment.

[0078] The imaging device 1 is a so-called digital single-lens reflex camera (lens interchangeable camera), and the imaging lens 103 (optical system) has an optical element based on the optical glass of this embodiment. The lens barrel 102 is detachably mounted on the lens mount (not shown) of the camera body 101. Furthermore, the light passing through the lens 103 of the lens barrel 102 is imaged on the sensor chip (solid-state imaging element) 104 of the multi-chip module 106 disposed 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, for example, a COG (Chip On Glass) type module formed by bare chip mounting of the sensor chip 104 on a glass substrate 105.

[0079] Figure 2 This is a front view of another example of a camera device equipped with an optical element using the optical glass of this embodiment. Figure 3 yes Figure 2 Rear view of the camera device.

[0080] The camera device CAM is a so-called digital still camera (lens-free camera), and the camera lens WL (optical system) has optical elements based on the optical glass of this embodiment.

[0081] In the camera device CAM, pressing the power button (not shown) opens the shutter (not shown) of the camera lens WL, allowing light from the subject (object) to be focused by the camera lens WL and imaged in the image sensor located on the image plane. The image of the subject in the image sensor is displayed on the LCD monitor LM located on the back of the camera device CAM. The photographer observes the LCD monitor LM while determining the composition of the subject image, then presses the release button B1 to capture the image using the image sensor, which is then recorded and saved in the memory (not shown).

[0082] The camera device CAM is equipped with an auxiliary light emitting part EF that emits auxiliary light when the subject is dark, and function buttons B2 for setting various conditions of the camera device CAM.

[0083] Optical systems used in digital cameras and similar devices require higher resolution, lighter weight, and smaller size. To achieve these performance characteristics, using high-refractive-index glass in the optical system is effective. This is especially true for high-refractive-index glass with lower specific gravity (Sg). g There is a high demand for glass with high-pressure molding properties. Based on the above, the optical glass of this embodiment is suitable as a component of the aforementioned optical device. It should be noted that the optical device applicable to this embodiment is not limited to the aforementioned camera device, but can also include, for example, a projector. The optical element is not limited to a lens, but can also include, for example, a prism.

[0084] Multiphoton Microscopy

[0085] Figure 4 This is a block diagram showing an example configuration of a multiphoton microscope 2 equipped with optical elements using the optical glass of this embodiment.

[0086] The multiphoton microscope 2 includes an objective lens 206, a condenser lens 208, and an imaging lens 210. At least one of the objective lens 206, the condenser lens 208, and the imaging lens 210 has an optical element based on the optical glass of this embodiment. Hereinafter, the optical system of the multiphoton microscope 2 will be described in detail.

[0087] The pulsed laser device 201 emits, for example, ultrashort pulses of light with a near-infrared wavelength (approximately 1000 nm) and a pulse width in femtosecond units (e.g., 100 femtoseconds). The ultrashort pulses immediately after being emitted from the pulsed laser device 201 typically become linearly polarized light with polarization along a specified direction.

[0088] The pulse segmentation device 202 segments the ultrashort pulse light and emits it after increasing the repetition frequency of the ultrashort pulse light.

[0089] The beam adjustment unit 203 has the following functions: adjusting the beam diameter of the ultrashort pulse light incident from the pulse splitting device 202 according to the pupil diameter of the objective lens 206; adjusting the convergence and divergence angles of the ultrashort pulse light to correct the axial chromatic aberration (focal length difference) between the wavelength of the multiphoton excitation light emitted from the sample S and the wavelength of the ultrashort pulse light; and pre-chirping (group velocity dispersion compensation function) to impart the opposite group velocity dispersion to the ultrashort pulse light to correct the widening of the pulse width of the ultrashort pulse light during its passage through the optical system; etc.

[0090] The ultrashort pulse light emitted from the pulsed laser device 201 has its repetition frequency increased by the pulse splitting device 202, and this adjustment is performed by the beam adjustment unit 203. Then, the ultrashort pulse light emitted from the beam adjustment unit 203 is reflected by the dichroic mirror 204 towards the dichroic mirror 205, and after passing through the dichroic mirror 205, it is focused by the objective lens 206 and illuminates the sample S. At this time, the ultrashort pulse light can also be scanned on the observation surface of the sample S by using a scanning unit (not shown).

[0091] For example, in the case of fluorescence observation of sample S, in the area of ​​sample S irradiated by ultrashort pulse light and its vicinity, the fluorescent dye that stains sample S is excited by multiphotons and emits fluorescence with a wavelength shorter than that of ultrashort pulse light belonging to the infrared wavelength (hereinafter referred to as "observation light").

[0092] The observation light emitted from the sample S toward the objective lens 206 is collimated by the objective lens 206 and, depending on its wavelength, is either reflected by or transmitted through the dichroic mirror 205.

[0093] 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 suppression filter or a PMT (photomultiplier tube), and receives the observation light reflected by the dichroic mirror 205, outputting an electrical signal corresponding to the amount of light. In addition, the fluorescence detection unit 207, in conjunction with the scanning of the observation surface of the sample S by an ultrashort pulse light, detects the observation light on the observation surface of the sample S.

[0094] On the other hand, the observation light passing through the dichroic mirror 205 is descanned by the scanning unit (not shown), passes through the dichroic mirror 204, is converged by the condenser lens 208, passes through the pinhole 209 located at a position approximately conjugate to the focal point of the objective lens 206, passes through the imaging lens 210, and enters the fluorescence detection unit 211.

[0095] The fluorescence detection unit 211 is composed of, for example, a suppression filter or a PMT, and receives the observation light imaged on the light receiving surface of the fluorescence detection unit 211 by the imaging lens 210, and outputs an electrical signal corresponding to the amount of light. In addition, the fluorescence detection unit 211 detects the observation light on the observation surface of the sample S in conjunction with the scanning of the ultrashort pulse light on the observation surface of the sample S.

[0096] It should be noted that the dichroic mirror 205 can also be removed from the optical path, and the fluorescence detection unit 211 can be used to detect all the observation light emitted from the sample S toward the objective lens 206.

[0097] Furthermore, 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, for example, is composed of a suppression filter, a PMT, etc., receives the observation light reflected by the dichroic mirror 212, and outputs an electrical signal corresponding to the amount of light. In addition, the fluorescence detection unit 213, in conjunction with the scanning of the observation surface of the sample S by an ultrashort pulse light, detects the observation light on the observation surface of the sample S.

[0098] The electrical signals output from the fluorescence detection units 207, 211, and 213 are, for example, input into a computer (not shown). The computer generates an observation image based on the input electrical signals and can display the generated observation image or store the data of the observation image.

[0099] Example

[0100] Next, embodiments and comparative examples of the present invention will be described. The present invention is not limited to these embodiments. Optical glass was fabricated as follows, and its physical properties were evaluated.

[0101] <Fabrication of Optical Glass>

[0102] The optical glasses of each embodiment and comparative example were prepared according to the following procedure. First, glass raw materials selected from oxides, hydroxides, phosphoric acid compounds (phosphates, orthophosphoric acid, etc.), carbonates, sulfates, fluorides, and nitrates were weighed according to the composition described in each table. Next, the weighed raw materials were mixed and placed in a platinum crucible, melted at a temperature of 1100–1300°C for about 70 minutes, and stirred until homogenized. After defoaming, the temperature was lowered to an appropriate level and poured into a mold, then slowly cooled to form the samples.

[0103] <Refractive index (n d ) and Abbe number (ν d )>

[0104] The refractive index of each sample was determined according to Japanese Industrial Standard JIS B 7071-1:2015 "Method for Determination of Refractive Index of Optical Glass". The refractive index (n) was used for measurement and calculation. d The Abbe number (ν) represents the refractive index of glass for d-rays (wavelength 587.562 nm). d n is obtained through the following formula (1). C n F These represent the refractive indices of the glass for C-rays (wavelength 656.273 nm) and F-rays (wavelength 486.133 nm), respectively.

[0105] ν d =(n d -1) / (n F -n C )……(1)

[0106] Partial dispersion ratio (P) g,F )>

[0107] Partial dispersion ratio (P) of each sample g,F ) represents partial dispersion (n g -n F ) relative to the principal dispersion (n F -n C The ratio of n to n can be obtained using the following formula (2). g This represents the refractive index of the glass to gamma rays (wavelength 435.835 nm).

[0108] P g,F =(n g -n F ) / (n F -n C )……(2)

[0109] < represents the value of anomalous dispersion (ΔP) g,F )>

[0110] The anomalous dispersion value (ΔP) of each sample was determined using the method shown below. g,F ).

[0111] (1) Making the baseline

[0112] First, as a normal partially dispersive glass, an Abbe number (ν) with the following characteristics is used. d ) and partial dispersion ratio (P g,F Two types of glass, "F2" and "K7", were used as reference materials. Then, for each glass, the Abbe number (ν) was taken as the horizontal axis. d The vertical axis represents the partial dispersion ratio (P). g,F The straight line connecting the two points corresponding to the two reference materials is used as the reference line.

[0113] Properties of glass "F2": ν d =36.33、P g,F =0.5834

[0114] Properties of glass "K7": ν d =60.47、P g,F =0.5429

[0115] Baseline: P g,F +0.00161783×ν d -0.64146248

[0116] (2)ΔP g,F Calculation

[0117] Next, on the horizontal axis, the Abbe number (ν) d The vertical axis represents the partial dispersion ratio (P). g,F Plot the values ​​corresponding to each type of glass on the graph, and calculate the Abbe number (ν) for each type of glass. d The point on the baseline corresponding to ) and its value on the vertical axis (P) g,F The difference between ΔP and ΔP is used as a value representing anomalous dispersion. g,F ). Figure 5 The Abbe number (ν) of each embodiment and each comparative example is shown. d ) and partial dispersion ratio (P g,F The graph is created by plotting the partial dispersion ratio (P). It should be noted that in the partial dispersion ratio (P... g,F When ΔP is located above the baseline, g,F It has a positive value in the partial dispersion ratio (P g,F When ΔP is located below the baseline, g,F It has negative values.

[0118] Specific gravity (S) g )>

[0119] Specific gravity (S) of each sample g The specific gravity was determined according to the Japanese Engineering Glass Industry Association standard JOGIS J05-1975 "Method for Determination of Specific Gravity of Optical Glass".

[0120] Glass transition temperature (T) g )>

[0121] The glass transition temperature (T0) of each sample was calculated from the DTA curves obtained by differential thermal analysis (glass powder placed in a Pt dish, heated at an atmospheric rate of 10 °C / min). g ).

[0122] <Devitrification Resistance Test>

[0123] Each sample was melted at 1050–1100 °C for 30 minutes (without a lid), and then cooled directly at a rate of 100 °C / hour to the glass transition temperature (T). g The following criteria are used to visually evaluate whether there is any loss of transparency.

[0124] A: The surface is only a very thin crystalline layer, and no crystallization into the interior was observed.

[0125] B: A state of crystallization was confirmed on the surface or part of the interior.

[0126] C: The sample is in a state of overall devitrification, or a state in which internal observation is difficult due to surface devitrification.

[0127] The composition and evaluation results of each embodiment and comparative example are shown in Tables 1-11. It should be noted that the "ΣTM" in the tables... n+ / F - As mentioned above, Ti is expressed in atomic % (at%). 4+ Ingredients+Zr 4+ Ingredient+Nb 5+ Ingredients+Ta 5+ Ingredients+W 6+ Ingredients (ΣTM) n+ (relative to F) - The proportions of the ingredients.

[0128] [Table 1]

[0129] [Table 2]

[0130] [Table 3]

[0131] [Table 4]

[0132] [Table 5]

[0133] [Table 6]

[0134] [Table 7]

[0135] [Table 8]

[0136] [Table 9]

[0137] [Table 10]

[0138] [Table 11]

[0139] The optical glass of this embodiment has been confirmed to have a high refractive index, low dispersion, and high anomalous dispersion. Furthermore, its excellent devitrification resistance is confirmed, which is extremely useful for suppressing ripples during glass manufacturing, particularly during molten forming.

[0140] Additionally, at the glass transition temperature (T) g Under high temperatures, glass tends to cure quickly, and the glass transition temperature (T) is high. g A high glass transition temperature (T0) helps suppress ripples. On the other hand, the glass transition temperature (T0)... g Li has the advantage of being a molding glass material with low heat resistance and minimal damage to molds. Therefore, in the case of such a requirement in the optical glass of this embodiment, it is also expected that the introduction of Li... + Adjustments are made to adjust the glass transition temperature (T) g It moves toward the low-temperature side.

Claims

1. An optical glass, wherein, In terms of cations (mol%), Contains 30%–45% P 5+ , Al content of 10% to 20% 3+ , Ba content of 20% to 40% 2+ , At least contains Li + Ti 4+ any one of them, In terms of mole percent of anions, O 2- The content is 75% to 95%. F - The content is 5% to 25%.

2. The optical glass as described in claim 1, wherein, Li, in molar percentage of cations + The content is 1% to 6%.

3. The optical glass as described in claim 2, wherein, In terms of cations (mol%), Ti 4+ The content is 0-6%.

4. The optical glass as described in claim 1, wherein, In terms of cations (mol%), Ti 4+ The content is 0.5% to 6%.

5. The optical glass as described in claim 4, wherein, Li, in molar percentage of cations + The content is 0-6%.

6. The optical glass according to any one of claims 1 to 5, wherein, In terms of cations (mol%), Mg 2+ Content is 0-15%, Ca 2+ Content is 0-20%, Sr 2+ Content is 0-20%, Zn 2+ Content is 0-15%, Y 3+ Content is 0-6%, La 3+ Content is 0-6%, Gd 3+ Content is 0-6%, Zr 4+ Content is 0-3%, Nb 5+ Content is 0-8%, Ta 5+ Content is 0-4%. W 6+ The content is 0-6%.

7. The optical glass according to any one of claims 1 to 5, wherein, In terms of cations (mol%), P 5+ And Al 3+ The total content, i.e., P 5+ +Al 3+ It ranges from 40% to 65%.

8. The optical glass according to any one of claims 1 to 5, wherein, In terms of cations (mol%), Mg 2+ Ca 2+ 、Sr 2+ Ba 2+ and Zn 2+ The total content is ΣAE 2+ It ranges from 35% to 50%.

9. The optical glass according to any one of claims 1 to 5, wherein, In terms of cations (mol%), Y 3+ La 3+ and Gd 3+ The total content is ΣRE 3+ It ranges from 0% to 6%.

10. The optical glass according to any one of claims 1 to 5, wherein, In terms of cations (mol%), Ti 4+ Zr 4+ 、Nb 5+ Ta 5+ and W 6+ The total content is ΣTM n+ More than 0 and less than 10%.

11. The optical glass according to any one of claims 1 to 5, wherein, Based on the mole % of cations, P 5+ Content relative to Al 3+ The proportion of content, i.e., P 5+ / Al 3+ It ranges from 1.5 to 4.

5.

12. The optical glass according to any one of claims 1 to 5, wherein, Based on the mole % of cations, Ba 2+ and Zn 2+ Total content relative to Mg 2+ Ca 2+ and Sr 2+ The proportion of the total content, i.e. (Ba 2+ +Zn 2+ ) / (Mg 2+ +Ca 2+ +Sr 2+ The value ranges from 0.5 to 10.

13. The optical glass according to any one of claims 1 to 5, wherein, Based on the mole % of cations, Li + Mg 2+ Ca 2+ 、Sr 2+ Ba 2+ Zn 2+ Y 3+ La 3+ Gd 3+ Ti 4+ Zr 4+ 、Nb 5+ Ta 5+ and W 6+ Total content relative to P 5 + And Al 3+ The proportion of the total content, i.e. (Li + +ΣAE 2+ +ΣRE 3+ +ΣTM n+ ) / (P 5+ +Al 3+ The value ranges from 0.7 to 1.

3.

14. The optical glass according to any one of claims 1 to 5, wherein, For cationic components, the percentage is expressed as mol% of cations; for anionic components, the percentage is expressed as mol% of anions. Ti 4+ Zr 4+、 Nb 5+ Ta 5+ and W 6+ The total content is ΣTM n+ Relative to F - The proportion of content is (ΣTM) n+ ) / F - The value ranges from 0.05 to 0.

35.

15. The optical glass according to any one of claims 1 to 5, wherein, Refractive index n d The range is 1.60 to 1.

70.

16. The optical glass according to any one of claims 1 to 5, wherein, Abbe number ν d The range is 40 to 65.

17. The optical glass according to any one of claims 1 to 5, wherein, Partial dispersion ratio P g,F The value ranges from 0.550 to 0.

570.

18. The optical glass according to any one of claims 1 to 5, wherein, ΔP g,F It ranges from 0.005 to 0.

015.

19. The optical glass according to any one of claims 1 to 5, wherein, Specific gravity S g The range is 3.90 to 4.

20.

20. The optical glass according to any one of claims 1 to 5, wherein, Glass transition temperature T g Below 650℃.

21. An optical element that uses the optical glass according to any one of claims 1 to 20.

22. An optical system comprising the optical element of claim 21.

23. A replaceable lens comprising the optical system of claim 22.

24. An optical device comprising the optical system of claim 22.

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