Optical glass, optical element, optical system, bonded lens, interchangeable lens for camera, objective lens for microscope, and optical device

Abstract

An optical glass comprising, in mass%, P2O5: 20 to 50%, TiO2: 10 to 35%, Nb2O5: 0 to 20%, Bi2O3: 5 to 30%, and the ratio of the TiO2 content to the P2O5 content, TiO2 / P2O5, being 0.30 to 0.75.

Description

Technical Field

[0001] This invention relates to optical glass, optical elements, optical systems, coupling lenses, interchangeable lenses for cameras, objective lenses for microscopes, and optical devices. Background Technology

[0002] In recent years, camera devices with high pixel count image sensors have been developed, and optical glass used in these devices requires optical glass with low dispersion and high partial dispersion ratio.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2006-219365 Summary of the Invention

[0006] The first aspect of the present invention relates to an optical glass, wherein, by mass%, the P2O5 content is 20-50%, the TiO2 content is 10-35%, the Nb2O5 content is 0-20%, the Bi2O3 content is 5-30%, and the ratio of TiO2 content to P2O5 content, i.e., TiO2 / P2O5, is 0.30-0.75.

[0007] A second aspect of the present invention relates to an optical element that uses the aforementioned optical glass.

[0008] A third aspect of the present invention relates to an optical system comprising the optical elements described above.

[0009] The fourth aspect of the present invention relates to a replaceable lens for a camera, comprising: an optical system including the optical elements described above.

[0010] The fifth aspect of the present invention relates to a microscope objective lens comprising: an optical system including the optical elements described above.

[0011] The sixth aspect of the present invention relates to an optical device comprising: an optical system including the optical elements described above.

[0012] The seventh aspect of the present invention relates to a bonding lens having a first lens element and a second lens element, at least one of which is the aforementioned optical glass.

[0013] The eighth aspect of the present invention relates to an optical system comprising the aforementioned conjugate lens.

[0014] The ninth aspect of the present invention relates to a microscope objective lens comprising: an optical system including the aforementioned conjoint lens.

[0015] The tenth aspect of the present invention relates to a replaceable lens for a camera, comprising: an optical system including the aforementioned coupling lens.

[0016] The eleventh aspect of the present invention relates to an optical device comprising: an optical system including the aforementioned coupling lens. Attached Figure Description

[0017] Figure 1 This is a perspective view showing an example of using the optical device of this embodiment as a camera device.

[0018] Figure 2 This is a schematic diagram showing another example of using the optical device of this embodiment as a camera device, which is a front view of the camera device.

[0019] Figure 3 This is a schematic diagram showing another example of using the optical device of this embodiment as a camera device, which is a rear view of the camera device.

[0020] Figure 4 This is a block diagram illustrating an example of the configuration of the multiphoton microscope of this embodiment.

[0021] Figure 5 This is a schematic diagram illustrating an example of the bonding lens of this embodiment.

[0022] Figure 6 P is for each embodiment and each comparative example g,F and ν d A diagram created by drawing a graph. Detailed Implementation

[0023] The following describes embodiments of the present invention (hereinafter referred to as "this embodiment"). This embodiment is merely an illustration of the present invention and is not intended to limit the invention to its specific contents. The present invention can be implemented with appropriate modifications within the scope of its essential points.

[0024] In this specification, unless otherwise stated, the content of each component is expressed as a percentage of mass relative to the total weight of the glass as a glass composition converted from oxides. It should be noted that the oxide composition referred to here means the following composition: assuming that the oxides, complex salts, etc., used as raw materials that are components of the glass in this embodiment decompose completely into oxides during melting, the total mass of these oxides is set as 100% by mass to represent each component contained in the glass.

[0025] In addition, the statement that the Q content is "0 to N%" includes cases where the Q component is not present and cases where the Q component is more than 0% but less than N%.

[0026] Furthermore, the statement "does not contain component Q" means that component Q is not substantially present, and its content is below the impurity level. Below the impurity level means, for example, less than 0.01%.

[0027] The term "resistance to devitrification stability" refers to the glass's resistance to devitrification. Here, "devitrification" refers to the loss of transparency of the glass caused by crystallization or phase separation when the glass is heated above its glass transition temperature or cooled from a molten state to below its liquidus temperature.

[0028] The optical glass in this embodiment is an optical glass with the following composition by mass: 20-50% P2O5, 10-35% TiO2, 0-20% Nb2O5, 5-30% Bi2O3, and a TiO2 / P2O5 ratio of 0.30 to 0.75.

[0029] The optical glass of this embodiment can improve part of the dispersion ratio while maintaining low dispersion (high Abbe number), thus being advantageous for correcting chromatic aberration and enabling the realization of lightweight lenses.

[0030] P2O5 is a component that forms the glass framework, improves devitrification resistance, and reduces refractive index and chemical durability. If the P2O5 content is too low, devitrification is more likely to occur. Conversely, if the P2O5 content is too high, refractive index and chemical durability tend to decrease. Therefore, the P2O5 content is preferably 20% to 50%. The lower limit of this content is preferably 25%, more preferably 30%, and even more preferably 35%. The upper limit of this content is preferably 45%, more preferably 40%, and even more preferably 38%. By maintaining the P2O5 content within this range, a high refractive index can be achieved while simultaneously improving devitrification resistance and chemical durability.

[0031] TiO2 is a component that increases the refractive index and partial dispersion ratio, while decreasing transmittance. If the TiO2 content is too low, the refractive index and partial dispersion ratio tend to decrease. If the TiO2 content is too high, the transmittance tends to deteriorate. Therefore, from this perspective, the TiO2 content is 10% to 35% or less. The lower limit of this content is preferably 15%, more preferably 17%, and even more preferably 20%. The upper limit of this content is preferably 30%, more preferably 28%, and even more preferably 25%. By keeping the TiO2 content within this range, high transmittance can be achieved without decreasing the refractive index and partial dispersion ratio.

[0032] Nb₂O₅ is a component that increases refractive index and dispersion while decreasing transmittance. Low Nb₂O₅ content tends to decrease refractive index. Conversely, high Nb₂O₅ content tends to degrade transmittance. Therefore, the Nb₂O₅ content is 0% to 20%. The lower limit of this content can exceed 0%. The upper limit of this content is preferably 10%, more preferably 5%. Further preferably, it is substantially absent.

[0033] Bi₂O₃ is a component that improves refractive index and partial dispersion ratio. Excessive Bi₂O₃ content tends to degrade transmittance and increase dispersion. Insufficient Bi₂O₃ content tends to decrease solubility. Therefore, the Bi₂O₃ content is preferably 5% to 30%. The lower limit of this content is preferably 10%, more preferably 15%. The upper limit of this content is preferably 25%, more preferably 20%. By maintaining the Bi₂O₃ content within this range, solubility can be improved and increased dispersion can be prevented.

[0034] The ratio of TiO2 content to P2O5 content (TiO2 / P2O5) is preferably 0.30 to 0.75. Furthermore, the lower limit of this ratio is more preferably 0.40. The upper limit of this ratio is more preferably 0.70, and even more preferably 0.60. By setting the TiO2 / P2O5 ratio to this range, the partial dispersion ratio can be improved.

[0035] The optical glass of this embodiment may also contain one or more of the following optional components selected from the group consisting of Al2O3, Ta2O5, Li2O, Na2O, K2O, ZnO, MgO, CaO, SrO, BaO, SiO2, B2O3, WO3, ZrO2, Sb2O3, Y2O3, La2O3, and Gd2O3.

[0036] Al2O3 is a component that improves chemical durability, reduces partial dispersion ratio, and improves solubility. If the Al2O3 content is too low, chemical durability tends to decrease. If the Al2O3 content is too high, partial dispersion ratio tends to decrease, and solubility deteriorates. Based on this, the Al2O3 content is 0% to 10%. The lower limit of this content is preferably more than 0%, more preferably 1%. The upper limit of this content is preferably 7%, more preferably 2%, and even more preferably 1.6%. By keeping the Al2O3 content within this range, chemical durability can be improved, and a decrease in partial dispersion ratio can be prevented.

[0037] Ta₂O₅ is a component that increases refractive index and dispersion, but reduces devitrification stability. A high Ta₂O₅ content tends to degrade devitrification stability. Therefore, the Ta₂O₅ content is 0% to 20%. The lower limit of this content can exceed 0%. The upper limit is preferably 10%, more preferably 5%. Even more preferably, it contains no Ta. "Substantially does not contain" means that the component is not present as a component whose concentration exceeds the level unavoidable as an impurity and affects the properties of the glass composition. For example, a content of around 100 ppm is considered substantially non-existent. The optical glass of this embodiment can reduce the content of Ta₂O₅, a high-cost raw material, and may even be completely free of Ta₂O₅, thus offering excellent raw material cost advantages.

[0038] From the viewpoint of meltability, the Li₂O content is 0% to 5%. The lower limit of this content can exceed 0%. The upper limit of this content is preferably 4%, more preferably 3%, and even more preferably 2%.

[0039] Na₂O is a component that improves meltability and reduces refractive index. If the Na₂O content is too low, meltability tends to decrease. If the Na₂O content is too high, refractive index and chemical durability tend to decrease. Based on this, the Na₂O content is 0% to 25%. The lower limit of this content is preferably more than 0%, more preferably 5%. The upper limit of this content is preferably 20%, more preferably 18%, and even more preferably 15%. By keeping the Na₂O content within this range, meltability can be improved, and the decrease in refractive index and chemical durability can be prevented.

[0040] K₂O is a component that improves meltability and reduces refractive index. If the K₂O content is too low, meltability tends to decrease. If the K₂O content is too high, refractive index and chemical durability tend to decrease. Based on this, the K₂O content is 0% to 25%. The lower limit of this content is preferably more than 0%, more preferably 3%. The upper limit of this content is preferably 20%, more preferably 15%, and even more preferably 10%. By keeping the K₂O content within this range, meltability can be improved, and the decrease in refractive index and chemical durability can be prevented.

[0041] ZnO is a component that improves devitrification resistance and reduces partial dispersion ratio. If the ZnO content is too low, devitrification resistance tends to decrease. If the ZnO content is too high, partial dispersion ratio tends to decrease. Based on this, the ZnO content is 0% to 15%. The lower limit of this content is preferably more than 0%, more preferably 1%. The upper limit of this content is preferably 12%, more preferably 8%, and even more preferably 5%. By keeping the ZnO content within this range, devitrification resistance can be improved and a decrease in partial dispersion ratio can be prevented.

[0042] From the viewpoint of high dispersion, the MgO content is 0% to 10%. The lower limit of this content can exceed 0%. The upper limit of this content is preferably 8%, more preferably 5%, and even more preferably 3%.

[0043] From the viewpoint of high dispersion, the CaO content is 0% to 8%. The lower limit of this content can exceed 0%. The upper limit of this content is preferably 5%, more preferably 3%, and even more preferably 2%.

[0044] From the viewpoint of high dispersion, the SrO content is 0% to 10%. The lower limit of this content can exceed 0%. The upper limit of this content is preferably 8%, more preferably 5%, and even more preferably 3%.

[0045] BaO is a component that increases the partial dispersion ratio and decreases devitrification resistance. If the BaO content is too low, the partial dispersion ratio tends to decrease. If the BaO content is too high, the devitrification resistance tends to decrease. Based on this, the BaO content is 0% to 15%. The lower limit of this content is preferably more than 0%, more preferably 5%, and even more preferably 7%. The upper limit of this content is preferably 12%, more preferably 10%, and even more preferably 8%. By keeping the BaO content within this range, the partial dispersion ratio can be improved and the decrease in devitrification resistance can be prevented.

[0046] From a melting point of view, the SiO2 content is 0% to 5%. The lower limit of this content can exceed 0%. The upper limit of this content is preferably 4%, more preferably 2%, and even more preferably 1%.

[0047] From the viewpoint of high dispersion, the content of B2O3 is between 0% and 10%. The lower limit of this content can exceed 0%. The upper limit of this content is preferably 8%, more preferably 5%, and even more preferably 3%.

[0048] From the viewpoint of transmittance, the WO3 content is 0% to 25%. The lower limit of this content can exceed 0%. The upper limit of this content is preferably 20%, more preferably 18%, and even more preferably 15%.

[0049] From the viewpoint of meltability, the ZrO2 content is 0% to 5%. The lower limit of this content can exceed 0%. The upper limit of this content is preferably 3%, more preferably 2%, and even more preferably 1.5%.

[0050] From a meltability perspective, the Y₂O₃ content is 0% to 10%. The lower limit of this content can exceed 0%. The upper limit of this content is preferably 7%, more preferably 6%, and even more preferably 5%.

[0051] From a meltability perspective, the La2O3 content is 0% to 8%. The lower limit of this content can exceed 0%. The upper limit is preferably 7%, more preferably 6%, and even more preferably 5%. Furthermore, from a cost perspective, it is even more preferable that La2O3 is substantially absent. "Substantially absent" means that the component is not present as a constituent that exceeds a concentration unavoidably present as an impurity and affects the properties of the glass composition. For example, a content of approximately 100 ppm is considered substantially absent.

[0052] Gd₂O₃ is a high-priced raw material; therefore, its content is between 0% and 10%. The lower limit of this content can exceed 0%. The upper limit of this content is preferably 8%, more preferably 7%, and even more preferably 5%.

[0053] From the viewpoint of degassing during glass melting, the Sb₂O₃ content is 0–1%. The lower limit of this content can exceed 0%. The upper limit of this content is preferably 0.5%, more preferably 0.2%.

[0054] Furthermore, the optical glass in this embodiment preferably satisfies the following relationship.

[0055] The ratio of Al2O3 content to TiO2 content (Al2O3 / TiO2) is preferably 0 to 0.60. Furthermore, the lower limit of this ratio can exceed 0. The upper limit of this ratio is preferably 0.50, more preferably 0.30. By setting the Al2O3 / TiO2 ratio to this range, the partial dispersion ratio can be improved.

[0056] The ratio of B2O3 content to P2O5 content (B2O3 / P2O5) is preferably 0 to 0.15. Furthermore, the lower limit of this ratio can exceed 0. The upper limit of this ratio is preferably 0.12, more preferably 0.09. By setting the B2O3 / P2O5 ratio to this range, the partial dispersion ratio can be improved.

[0057] The ratio of TiO2 content to the total content of P2O5, B2O3, and Al2O3 (TiO2 / (P2O5+B2O3+Al2O3)) is preferably 0.25 to 0.75. Furthermore, the lower limit of this ratio is more preferably 0.35, and even more preferably 0.40. The upper limit of this ratio is more preferably 0.70, and even more preferably 0.60. By setting TiO2 / (P2O5+B2O3+Al2O3) within this range, the partial dispersion ratio can be improved.

[0058] The ratio of TiO2 content to the total content of TiO2, Nb2O5, WO3, Bi2O3, and Ta2O5 (TiO2 / (TiO2+Nb2O5+WO3+Bi2O5)) 3+ The ratio of TiO2 / (TiO2+Nb2O5+WO3+Bi2O5) is preferably 0.20 to 0.90. Furthermore, the lower limit of this ratio is more preferably 0.30, and even more preferably 0.50. The upper limit of this ratio is more preferably 0.80, and even more preferably 0.70. This is achieved by making the ratio of TiO2 / (TiO2+Nb2O5+WO3+Bi2O5)... 3+ Ta2O5) falls within this range, which can improve part of the dispersion ratio.

[0059] The ratio of the total content of BaO and TiO2 to the content of P2O5 ((BaO+TiO2) / P2O5) is preferably 0.30 to 1.00. Furthermore, the lower limit of this ratio is more preferably 0.40, and even more preferably 0.50. The upper limit of this ratio is more preferably 0.90, and even more preferably 0.80. By setting (BaO+TiO2) / P2O5 within this range, the refractive index can be improved.

[0060] The ratio of the total content of BaO, TiO2, Nb2O5, WO3, Bi2O3, and Ta2O5 to the total content of P2O5, B2O3, SiO2, and Al2O3 ((BaO+TiO2+Nb2O5+WO3+Bi2O3+Ta2O5) / (P2O5+B2O3+SiO2+Al2O3)) is preferably 0.50 to 2.50. Furthermore, the lower limit of this ratio is more preferably 0.60, and even more preferably 0.70. The upper limit of this ratio is more preferably 2.00, and even more preferably 1.70. By setting (BaO+TiO2+Nb2O5+WO3+Bi2O3+Ta2O5) / (P2O5+B2O3+SiO2+Al2O3) within this range, the partial dispersion ratio can be improved, and a decrease in refractive index can be prevented.

[0061] From the viewpoints of meltability, refractive index, and chemical durability, the total content of Li₂O, Na₂O, and K₂O (ΣA₂O; where A = Li, Na, K) is 5% to 35%. The lower limit of this total content is preferably 8%, more preferably 11%, and even more preferably 13%. The upper limit of this total content is preferably 33%, more preferably 30%, and even more preferably 25%.

[0062] From the viewpoints of meltability, refractive index, and chemical durability, the total content (ΣEO; where E = Mg, Ca, Sr, Ba, Zn) of MgO, CaO, SrO, BaO, and ZnO is 0–18%. The lower limit of this total content is preferably 3%, more preferably 5%. The upper limit of this total content is preferably 15%, more preferably 13%.

[0063] As a preferred combination of these contents, the Li₂O content is 0% to 5%, the Na₂O content is 0% to 25%, and the K₂O content is 0% to 25%. This combination improves meltability and prevents a decrease in chemical durability.

[0064] As another preferred combination, the BaO content is 0% to 15%, the ZnO content is 0% to 15%, the MgO content is 0% to 10%, the CaO content is 0% to 8%, and the SrO content is 0% to 10%. This combination can improve the dispersion ratio and prevent low dispersion.

[0065] As another preferred combination, the SiO2 content is 0% to 5% and the B2O3 content is 0% to 10%. This combination improves meltability and prevents low dispersion.

[0066] The ratio of the total content of Li₂O, Na₂O, and K₂O (ΣA₂O; where A = Li, Na, K) to the content of TiO₂ (ΣA₂O / TiO₂) is preferably 0.30 to 2.00. Furthermore, the lower limit of this ratio is more preferably 0.50, and even more preferably 0.60. The upper limit of this ratio is more preferably 1.50, and even more preferably 1.30. By setting ΣA₂O / TiO₂ within this range, the partial dispersion ratio can be improved, and a decrease in meltability can be prevented.

[0067] The ratio of the total content of MgO, CaO, SrO, BaO, and ZnO (ΣEO; where E = Mg, Ca, Sr, Ba, Zn) to the total content of Li₂O, Na₂O, and K₂O (ΣA₂O; where A = Li, Na, K) (ΣEO / ΣA₂O) is preferably 0 to 1.50. Furthermore, the lower limit of this ratio is more preferably 0.40, and even more preferably 0.90. The upper limit of this ratio is more preferably 1.30, and even more preferably 1.20. By setting ΣEO / ΣA₂O within this range, meltability can be improved and a decrease in refractive index can be prevented.

[0068] In addition, known clarifying agents, coloring agents, defoaming agents, fluorine compounds, 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 constant values. Furthermore, other components may be added within the range that achieves the effects of the optical glass of this embodiment, and are not limited to the aforementioned components.

[0069] 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. For example, the following manufacturing method can be used: raw materials such as oxides, carbonates, nitrates, and sulfates are mixed in a manner to achieve the target composition, melted at a preferably 1100–1400°C, stirred to homogenize, defoamed, and then injected into a mold for molding. The lower limit of the above-mentioned melting temperature is more preferably 1200°C, and the upper limit is more preferably 1350°C, and even more preferably 1300°C. The optical glass obtained in this way can be further processed into the desired shape by reheating and pressing as needed, and then ground, thereby producing the desired optical element.

[0070] The preferred raw material is a high-purity product with a low impurity content. High purity means the component contains 99.85% by mass or more. By using high-purity raw materials, the amount of impurities is reduced, resulting in a tendency to improve the internal transmittance of the optical glass.

[0071] Next, the physical properties of the optical glass of this embodiment will be explained.

[0072] 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, the refractive index (n) is usually... d The higher the refractive index (n) of the d-line, the lower the transmittance tends to be. Based on this actual situation, the optical glass of this embodiment has a refractive index (n) of [missing information - likely related to the d-line]. d The preferred refractive index (n) is in the range of 1.61 to 1.90. Furthermore, the refractive index (n) is... d The lower limit of the refractive index (n) is preferably 1.70, more preferably 1.75, and the refractive index (n) is... dThe upper limit of ) is preferably 1.85, more preferably 1.80.

[0073] The Abbe number (ν) of the optical glass in this embodiment d The preferred range is 20 to 32. Furthermore, the Abbe number (ν) d The lower limit of ) is more preferably 22, and the Abbe number (ν) d The upper limit of ) is more preferably 30.

[0074] Regarding the refractive index (n) of the optical glass in this embodiment d ) and Abbe number (ν d The optimal combination of ) affects the refractive index (n) of the d-line. d The range is 1.61 to 1.90, and the Abbe number (ν) is... d The value ranges from 20 to 32. The optical glass of this embodiment, possessing this property, can be combined with, for example, other optical glasses to design optical systems where aberrations and other aberrations are well corrected.

[0075] From the perspective of lens aberration correction, the optical glass in this embodiment preferably has a large partial dispersion ratio (P0). g,F Based on this actual situation, the partial dispersion ratio (P) of the optical glass in this embodiment is... g,F The preferred value is 0.60 or higher. Furthermore, the partial dispersion ratio (P) is... g,F The lower limit of ) is more preferably 0.62, and even more preferably 0.64. Additionally, the partial dispersion ratio (P) g,F There is no specific upper limit for ), for example, it can be 0.66.

[0076] From the perspective of lens aberration correction, the optical glass in this embodiment preferably has a large anomalous dispersion (ΔP). g,F Based on this actual situation, the optical glass of this embodiment has a value (ΔP) representing anomalous dispersion. g,F The value is preferably 0.015 or higher. Furthermore, the value representing anomalous dispersion (ΔP) g,F The lower limit for ) is more preferably 0.02, and even more preferably 0.03. Additionally, the value representing anomalous dispersion (ΔP) g,F There is no specific upper limit for ), for example, it can be 0.042.

[0077] From the above perspective, the optical glass of this embodiment can be suitable for use as, for example, optical elements. Such optical elements include mirrors, lenses, prisms, filters, etc. Furthermore, examples of optical systems using the above-mentioned optical elements include, for example, objective lenses, condenser lenses, imaging lenses, and interchangeable lenses for cameras. Moreover, these optical systems can be used in various optical devices: imaging devices such as interchangeable-lens cameras and non-interchangeable-lens cameras, and microscope devices such as fluorescence microscopes and multiphoton microscopes. Optical devices are not limited to the above-mentioned imaging devices and microscopes, but also include, but are not limited to, telescopes, binoculars, laser rangefinders, projectors, etc. One example will be described below.

[0078] <Camera Device>

[0079] Figure 1 This is a perspective view showing the optical device of this embodiment as an example of a camera device. The camera device 1 is a so-called digital single-lens reflex camera (interchangeable lens camera), and the camera lens 103 (optical system) has optical elements using the optical glass of this embodiment as the base material. The lens barrel 102 is detachably mounted to 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 a COG (Chip On Glass) type module formed by mounting, for example, the sensor chip 104 as a bare chip on a glass substrate 105.

[0080] Figure 2 and Figure 3 This is a schematic diagram illustrating another example of using the optical device of this embodiment as a camera device. Figure 2 The front view of the camera device CAM is shown. Figure 3 The rear view of the camera device CAM is shown. The camera device CAM is a so-called digital still camera (non-interchangeable lens camera), and the camera lens WL (optical system) has optical elements with the optical glass of this embodiment as the base material.

[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 on the imaging element located on the image plane. The image of the subject on the imaging element is displayed on the LCD screen M located on the back of the camera device CAM. The photographer observes the LCD screen M while deciding on the composition of the subject image, then presses the release button B1 to capture the image using the imaging element and record it 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] For optical systems used in digital cameras and similar applications, higher resolution, lower chromatic aberration, and miniaturization are required. To achieve these capabilities, using glass with different dispersion characteristics within the optical system is effective. This is especially true for glass with low dispersion and a higher partial dispersion ratio (P0). g,F The demand for high-quality glass is high. Therefore, the optical glass of this embodiment is suitable as a component of the optical device. It should be noted that the optical device applicable to this embodiment is not limited to the aforementioned imaging device; examples such as projectors can also be cited. The optical element is not limited to a lens; examples such as prisms can also be cited.

[0084] <microscope>

[0085] Figure 4 This is a block diagram showing an example of the configuration of the multiphoton microscope 2 according to this embodiment. The multiphoton microscope 2 includes an objective lens 206, a converging lens 208, and an imaging lens 210. At least one of the objective lens 206, the converging lens 208, and the imaging lens 210 has an optical element made of the optical glass of this embodiment as the base material. The following description focuses on the optical system of the multiphoton microscope 2.

[0086] 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 femtoseconds (e.g., 100 femtoseconds). The ultrashort pulses immediately after being emitted from the pulsed laser device 201 typically form linearly polarized light with a specified polarization direction.

[0087] The pulse segmentation device 202 segments the ultrashort pulse light and emits it after increasing the repetition frequency of the ultrashort pulse light.

[0088] 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 in accordance with the pupil diameter of the objective lens 206; adjusting the convergence and divergence angles of the ultrashort pulse light in order to correct the chromatic aberration (focal difference) between the wavelength of the light emitted from the sample S and the wavelength of the ultrashort pulse light on the axis; and pre-chirping the ultrashort pulse light to correct the widening of the pulse width of the ultrashort pulse light due to group velocity dispersion during its passage through the optical system (group velocity dispersion compensation function), etc.

[0089] The ultrashort pulse light emitted from the pulsed laser device 201 has its repetition rate increased under the action of the pulse splitting device 202, and the beam adjustment unit 203 performs the aforementioned adjustment. Furthermore, the ultrashort pulse light emitted from the beam adjustment unit 203 is reflected by the dichroic mirror 204 towards the dichroic mirror, passes through the dichroic mirror 205, and is focused by the objective lens 206 to illuminate the sample S. At this time, the ultrashort pulse light can be scanned on the observation surface of the sample S using a scanning device (not shown).

[0090] 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 (hereinafter referred to as "observation light").

[0091] 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.

[0092] 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 blocking 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 detects the observation light on the observation surface of the sample S by scanning the observation surface with an ultrashort pulse of light.

[0093] It should be noted that, alternatively, the fluorescence detection unit 211 can detect all the observation light emitted from the sample S toward the objective lens 206 by removing the dichroic mirror 205 from the optical path. In this case, the observation light is descanned by the scanning device (not shown), passes through the dichroic mirror 204, is converged by the converging lens 208, passes through the pinhole 209 located approximately conjugate to the focal point of the objective lens 206, passes through the imaging lens 210, and enters the fluorescence detection unit 211.

[0094] The fluorescence detection unit 211 is composed of, for example, a blocking 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 by scanning the ultrashort pulse light on the observation surface of the sample S.

[0095] 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 blocking 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 detects the observation light on the observation surface of the sample S by scanning the ultrashort pulse light.

[0096] The electrical signals output by the fluorescence detection units 207, 211, and 213 are input into, for example, a computer (not shown). The computer can generate an observation image based on the input electrical signals, display the generated observation image, or store the data of the observation image.

[0097] <Joint Lens>

[0098] Figure 5 This is a schematic diagram illustrating an example of the combined lens of this embodiment. The combined lens 3 is a composite lens having a first lens element 301 and a second lens element 302. At least one of the first lens element and the second lens element uses the optical glass of this embodiment. The first lens element and the second lens element are joined by a joining member 303. As the joining member 303, known adhesives or the like can be used. It should be noted that the term "lens element" refers to each lens constituting a single lens or a combined lens.

[0099] The bonded lens of this embodiment is useful for chromatic aberration correction and is suitable for use in the aforementioned optical elements, optical systems, and optical devices. Furthermore, optical systems including the bonded lens are particularly suitable for interchangeable lenses for cameras, optical devices, and the like. It should be noted that the above description refers to a bonded lens using two lens elements, but it is not limited to this; a bonded lens using three or more lens elements may also be used. When manufacturing a bonded lens using three or more lens elements, at least one of the three or more lens elements may be formed using the optical glass of this embodiment.

[0100] Example

[0101] Next, embodiments and comparative examples of the present invention will be described. It should be noted that the present invention is not limited thereto.

[0102] <Fabrication of Optical Glass>

[0103] The optical glasses for 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, and nitrates were weighed according to the composition (mass %) listed in each table. Next, the weighed raw materials were mixed and placed in a platinum crucible, melted and stirred uniformly at a temperature of 1100–1300°C. After defoaming, the temperature was lowered to an appropriate level, then cast into a mold, annealed, and shaped to obtain each sample.

[0104] <Physical Property Evaluation>

[0105] Figure 6 P is for each embodiment and each comparative example g,F and ν d A diagram created by drawing a graph.

[0106] Refractive index (n) d ) and Abbe number (ν d )

[0107] Refractive index (n) of each sample d ) and Abbe number (ν d The refractive index was measured and calculated using a refractive index meter (manufactured by Shimadzu Device Co., Ltd.: KPR-2000). d This represents the refractive index of the glass for light at 587.562 nm. ν d It can be obtained from the following equation (1). C n F These represent the refractive indices of the glass for light with wavelengths of 656.273 nm and 486.133 nm, respectively.

[0108] ν d =(n d -1) / (n F -n C )···(1)

[0109] Partial dispersion ratio (P) g,F )

[0110] 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 from the following formula (2). g This represents the refractive index of the glass for light with a wavelength of 435.835 nm. Partial dispersion ratio (P...) g,F The value is up to the third decimal place.

[0111] P g,F =(n g -nF ) / (n F -n C (2)

[0112] Anomalous dispersion (ΔP) g,F )

[0113] Anomalous dispersion (ΔP) of each sample g,F This indicates the deviation from the partial dispersion ratio standard line relative to two types of glass with normal dispersion, F2 and K7. In other words, it represents the deviation from the partial dispersion ratio (P...) standard line relative to the standard line. g,F () is used as the vertical axis, and the Abbe value ν is used as the plot. d On the horizontal axis, the difference between the line connecting the two types of glass and the value of the glass used for comparison on the vertical axis represents the deviation of the partial dispersion ratio, i.e., anomalous dispersion (ΔP). g,F In the coordinate system described above, when the value of the partial dispersion ratio is located above the straight line connecting the standard glass types, the glass exhibits positive anomalous dispersion (+ΔP). g,F When the partial dispersion ratio is located at a lower position, the glass exhibits negative anomalous dispersion (-ΔP). g,F It should be noted that the Abbe numbers ν of F2 and K7... d and partial dispersion ratio (P g,F (See below.) F2: Abbe number ν d =36.33, Partial Dispersion Ratio (P) g,F ) = 0.5834

[0114] K7: Abbe number ν d =60.47, Partial Dispersion Ratio (P) g,F ) = 0.5429

[0115] Anomalous dispersion (ΔP) g,F The value is up to the third decimal place.

[0116] ΔP g,F =P g,F -(-0.0016777×ν d +0.6443513)···(3)

[0117] For the optical glasses of each embodiment and each comparative example, the composition of each component based on oxides (in mass%) and the evaluation results of each physical property are shown in Tables 1 to 11. In the formulas, “ΣA₂O” represents the total content of Li₂O, Na₂O, and K₂O (A = Li, Na, K). In the formulas, “ΣEO” represents the total content of MgO, CaO, SrO, BaO, and ZnO (E = Mg, Ca, Sr, Ba, Zn). Optical glasses could not be obtained for Comparative Examples 1 to 3, therefore their physical properties were “unmeasurable”.

[0118] [Table 1]

[0119]

[0120] [Table 2]

[0121]

[0122] [Table 3]

[0123]

[0124] [Table 4]

[0125]

[0126] [Table 5]

[0127]

[0128] [Table 6]

[0129]

[0130] [Table 7]

[0131]

[0132] [Table 8]

[0133]

[0134] [Table 9]

[0135]

[0136] [Table 10]

[0137]

[0138] [Table 11]

[0139]

[0140] Based on the above, it has been confirmed that the optical glass of this embodiment exhibits both high dispersion and high partial dispersion. Furthermore, it has been confirmed that the tinting of the optical glass of this embodiment is suppressed, and its transmittance is also excellent.

[0141] Symbol Explanation

[0142] 1. Imaging device; 101. Camera body; 102. Lens barrel; 103. Lens; 104. Sensor chip; 105. Glass substrate; 106. Multi-chip module; CAM. Imaging device (non-interchangeable lens camera); WL. Camera lens; M. Liquid crystal display; EF. Auxiliary light emission unit; B1. Release button; B2. Function button; 2. Multiphoton microscope; 201. ··Pulsed laser device, 202···Pulse splitting device, 203···Beam adjustment unit, 204, 205, 212···Dial mirror, 206···Objective lens, 207, 211, 213···Fluorescence detection unit, 208···Converging lens, 209···Pinhole, 210···Imaging lens, S···Sample, 3···Jointing lens, 301···First lens element, 302···Second lens element, 303···Jointing component.

Claims

1. An optical glass, wherein, In terms of mass %, The P2O5 content is between 20% and 50%. TiO2 content is between 12.66% and 35%. The Nb2O5 content is between 0% and 20%. The Bi2O3 content is between 5% and 30%. The ratio of TiO2 content to P2O5 content, i.e., TiO2 / P2O5, is between 0.30 and 0.

75. The ratio of TiO2 / (P2O5+B2O3+Al2O3) is above 0.33 and below 0.

75.

2. The optical glass as described in claim 1, wherein, The ratio of the total content of Li2O, Na2O and K2O, i.e. ΣA2O (A=Li, Na, K) to the content of TiO2, i.e. ΣA2O / TiO2, is between 0.30 and 2.

00.

3. An optical glass, wherein, In terms of mass %, The P2O5 content is between 20% and 50%. TiO2 content is between 10% and 35%. The Nb2O5 content is between 0% and 20%. Bi2O3 content is between 5% and 22.84%. The ratio of TiO2 content to P2O5 content, i.e., TiO2 / P2O5, is between 0.30 and 0.

75. The ratio of the total content of Li2O, Na2O and K2O, i.e. ΣA2O (A=Li, Na, K) to the content of TiO2, i.e. ΣA2O / TiO2, is between 0.3 and 1.

27.

4. The optical glass according to any one of claims 1 to 3, wherein, In terms of mass %, The TiO2 content is between 20.03% and 35%.

5. The optical glass according to any one of claims 1 to 3, wherein, TiO2 content is between 15% and 35%. The Al2O3 / TiO2 ratio is above 0.

18.

6. The optical glass according to any one of claims 1 to 3, wherein, In terms of mass %, Al2O3 content is between 0% and 10%. The Ta2O5 content is between 0% and 20%.

7. The optical glass according to any one of claims 1 to 3, wherein, In terms of mass %, The Li2O content is between 0% and 5%. Na2O content is between 0% and 25%. The K2O content is between 0% and 25%.

8. The optical glass according to any one of claims 1 to 3, wherein, In terms of mass %, ZnO content is between 0% and 15%. MgO content is between 0% and 10%. The CaO content is between 0% and 8%. The SrO content is between 0% and 10%. The BaO content is between 0% and 15%.

9. The optical glass according to any one of claims 1 to 3, wherein, In terms of mass %, The SiO2 content is between 0% and 5%. The B2O3 content is between 0% and 10%.

10. The optical glass according to any one of claims 1 to 3, wherein, In terms of mass %, The WO3 content is between 0% and 25%. The ZrO2 content is between 0% and 5%.

11. The optical glass according to any one of claims 1 to 3, wherein, In terms of mass %, Y2O3 content is between 0% and 10%. The La2O3 content is between 0% and 8%. The Gd2O3 content is between 0% and 10%.

12. The optical glass according to any one of claims 1 to 3, wherein, In terms of mass %, The Sb2O3 content is between 0% and 1%.

13. The optical glass according to any one of claims 1 to 3, wherein, In terms of mass %, The total content of Li2O, Na2O and K2O, i.e. ΣA2O (A=Li, Na, K), is between 5% and 35%.

14. The optical glass according to any one of claims 1 to 3, wherein, In terms of mass %, The total content of MgO, CaO, SrO, BaO and ZnO, i.e. ΣEO (E=Mg, Ca, Sr, Ba, Zn), is between 0% and 18%.

15. The optical glass according to any one of claims 1 to 3, wherein, The ratio of Al2O3 content to TiO2 content, i.e., Al2O3 / TiO2, is above 0 and below 0.

60.

16. The optical glass according to any one of claims 1 to 3, wherein, The ratio of B2O3 content to P2O5 content, i.e., B2O3 / P2O5, is above 0 and below 0.

15.

17. The optical glass according to any one of claims 1 to 3, wherein, The ratio of TiO2 content to the total content of TiO2, Nb2O5, WO3, Bi2O3, and Ta2O5, i.e., TiO2 / (TiO2+Nb2O5+WO3+Bi2O5), is given by: 3+ Ta2O5) is above 0.20 and below 0.

90.

18. The optical glass according to any one of claims 1 to 3, wherein, The ratio of the total content of BaO and TiO2 to the content of P2O5, i.e. (BaO+TiO2) / P2O5, is between 0.30 and 1.

00.

19. The optical glass according to any one of claims 1 to 3, wherein, The ratio of the total content of BaO, TiO2, Nb2O5, WO3, Bi2O3 and Ta2O5 to the total content of P2O5, B2O3, SiO2 and Al2O3, i.e. (BaO+TiO2+Nb2O5+WO3+Bi2O3+Ta2O5) / (P2O5+B2O3+SiO2+Al2O3), is between 0.50 and 2.

50.

20. The optical glass according to any one of claims 1 to 3, wherein, The ratio of the total content of MgO, CaO, SrO, BaO and ZnO, i.e. ΣEO (E=Mg, Ca, Sr, Ba, Zn), to the total content of Li2O, Na2O and K2O, i.e. ΣA2O (A=Li, Na, K), i.e. ΣEO / ΣA2O, is 0 or more and 1.50 or less.

21. The optical glass according to any one of claims 1 to 3, wherein, The refractive index n of the d-line d It is between 1.61 and 1.

90.

22. The optical glass according to any one of claims 1 to 3, wherein, Abbe number ν d The range is 20 to 32.

23. The optical glass according to any one of claims 1 to 3, wherein, Partial dispersion ratio P g,F It is between 0.60 and 0.

66.

24. The optical glass according to any one of claims 1 to 3, wherein, Anomalous dispersion ΔP g,F It is between 0.015 and 0.

042.

25. An optical element that uses the optical glass according to any one of claims 1 to 24.

26. An optical system comprising the optical element of claim 25.

27. A camera lens replacement comprising the optical system of claim 26.

28. A microscope objective comprising the optical system of claim 26.

29. An optical device comprising the optical system of claim 26.

30. A joining lens having a first lens element and a second lens element, At least one of the first lens element and the second lens element is the optical glass according to any one of claims 1 to 24.

31. An optical system comprising the bonding lens of claim 30.

32. A microscope objective lens comprising the optical system of claim 31.

33. A camera lens replacement comprising the optical system of claim 31.

34. An optical device comprising the optical system of claim 31.

Images