Optical sensor member and optical sensor device

Abstract

This optical sensor member contains aluminum oxide, titanium oxide, iron oxide, and a sintering aid, and does not contain cobalt oxide, chromium oxide, or manganese oxide. In addition, reflectance is 25% or less at all wavelengths in the wavelength range 500 nm to 2500 nm.

Description

Optical sensor component and optical sensor device

[0001] This disclosure relates to an optical sensor component and an optical sensor device.

[0002] Conventionally, monitoring devices equipped with optical sensors capable of detecting infrared light have been used in automobile factories, industrial machinery factories, medical facilities, nursing care facilities, plant facilities, and waste treatment facilities. For such monitoring devices to function correctly, optical sensor components with low reflectivity are required not only in the visible light region but also in the infrared light region.

[0003] This is because if a large amount of infrared light is reflected from an optical sensor component adjacent to the optical path within the optical sensor, this reflected infrared light enters the photodetector as significant noise, causing the signal-to-noise ratio of the photodetector to decrease.

[0004] Patent No. 5261038

[0005] A light sensor member according to one embodiment contains aluminum oxide, titanium oxide, iron oxide, and a sintering aid, but does not contain cobalt oxide, chromium oxide, or manganese oxide. Furthermore, its reflectance is 25% or less at all wavelengths in the wavelength range of 500 nm to 2500 nm.

[0006] Figure 1 shows the reflectance spectra of sample No. 16, sample No. 17, and sample No. 21 in the wavelength range of 200 nm to 2500 nm.

[0007] The embodiments of the optical sensor member and optical sensor device disclosed herein will be described in detail below. However, the present invention is not limited to the embodiments described below.

[0008] Conventionally, monitoring devices equipped with optical sensors capable of detecting infrared light have been used in automobile factories, industrial machinery factories, medical facilities, nursing care facilities, plant facilities, and waste treatment facilities. For such monitoring devices to function correctly, optical sensor components with low reflectivity are required not only in the visible light region but also in the infrared light region.

[0009] This is because if a large amount of infrared light is reflected from an optical sensor component adjacent to the optical path within the optical sensor, this reflected infrared light enters the photodetector as significant noise, causing the signal-to-noise ratio of the photodetector to decrease.

[0010] However, the optical sensor components used in the aforementioned monitoring devices still had room for improvement in terms of their ability to detect light, including infrared light. Therefore, there is a need to solve the above problems and realize a technology that enables optical sensor components to detect light, including infrared light, effectively.

[0011] The optical sensor components of this disclosure may include, for example, members adjacent to the optical path of the optical sensor device, such as a lens and a light-receiving element holder, a lens aperture member, and a light-receiving element cap member. The optical sensor device of this disclosure may be, for example, a device capable of detecting visible light and infrared light.

[0012] The optical sensor component of this disclosure may contain aluminum oxide, titanium oxide, and iron oxide. The optical sensor component of this disclosure may also contain a sintering aid. Such a sintering aid may be, for example, at least one of silicon oxide, calcium oxide, and magnesium oxide.

[0013] On the other hand, the optical sensor component of this disclosure does not need to contain cobalt oxide, chromium oxide, and manganese oxide. This can reduce the cost of the optical sensor component. In this disclosure, "not containing" is not limited to cases where the content is zero, but may also refer to cases where the content is below the detection limit of various analytical instruments.

[0014] The optical sensor member of this disclosure may have a reflectance of 25% or less at all wavelengths in the wavelength range of 500 nm to 2500 nm. This reduces the incidence of light, including infrared light, reflected from the surface of the optical sensor member as noise into the photodetector, thereby enabling an optical sensor device capable of detecting light, including infrared light, with good accuracy.

[0015] The light sensor member of the present disclosure may have a ratio of the reflectance at a wavelength of 2500 nm to the reflectance at a wavelength of 500 nm of 50% to 200%. Thereby, since the change in reflectance is small in both the visible light region and the infrared region, the design of noise countermeasures for the light sensor device can be facilitated.

[0016] The light sensor member of the present disclosure may exhibit black. Specifically, the light sensor member of the present disclosure has a ＊ and b ＊ that may be -2.0 or more and 2.0 or less. Here, a ＊ and b ＊ are values based on the CIE1976 (L ＊ a ＊ b ＊ ) color space. Note that a ＊ and b ＊ can be adjusted not only by the composition of the metal oxide contained in the light sensor member of the present disclosure but also by the firing temperature and firing time.

[0017] The light sensor member of the present disclosure may contain 67% by mass or more of aluminum oxide in terms of Al ２ O ３ , and may further contain 75% by mass or more of aluminum oxide. Also, the light sensor member of the present disclosure may contain 89.5% by mass or less of aluminum oxide in terms of Al ２ O ３ . Note that the content of aluminum oxide may be adjusted according to the content of other components described later.

[0018] The light sensor member of the present disclosure may contain a total of 10% by mass or more and 30% by mass or less of titanium oxide and iron oxide in terms of TiO ２ conversion and Fe ２ O ３ conversion, and may further contain a total of 20% by mass or more and 25% by mass or less of titanium oxide and iron oxide in terms of TiO ２ conversion and Fe ２ O ３ conversion.

[0019] In terms of TiO ２ conversion and Fe ２ O ３By including a combined total of 10% or more by mass of titanium dioxide and iron oxide, the resistivity of the optical sensor component can be reduced. ２ Conversion and Fe ２ O ３ By including titanium oxide and iron oxide in a combined amount of 30% by mass or less, the mechanical strength of the optical sensor component can be well maintained.

[0020] The optical sensor component disclosed herein is TiO ２ / (TiO ２ +Fe ２ O ３ ) may be 5% or more and 20% or less, and furthermore, TiO ２ / (TiO ２ +Fe ２ O ３ ) may be 15% or more and 20% or less.

[0021] TiO ２ / (TiO ２ +Fe ２ O ３ Having a TiO of 5% or more can lower the resistivity of the optical sensor component. ２ / (TiO ２ +Fe ２ O ３ The fact that the content is 20% or less allows the light sensor component to exhibit a good black color.

[0022] The optical sensor member disclosed herein is SiO ２ It may also contain a sintering aid totaling 0.5% by mass or more and 3.0% by mass or less, calculated on a convertible basis, on a CaO basis, and on a MgO basis.

[0023] SiO ２ By including a sintering aid of 0.5% by mass or more in terms of conversion, CaO conversion, and MgO conversion, the resistivity of the optical sensor component can be reduced. ２ By including a sintering aid of 3.0% by mass or less in total (calculated as CaO, MgO, or equivalent), the low reflectivity of the optical sensor component can be well maintained.

[0024] The optical sensor member of this disclosure may have a mirror-like surface. This further reduces the reflectance in the visible light region and the infrared light region. Therefore, according to the embodiment, an optical sensor device capable of detecting light, including infrared light, even better can be realized.

[0025] The optical sensor member disclosed herein has a volume resistivity of 1.0 × 10 ４ Ωcm or greater and 1.0 × 10 １１ It may be less than or equal to Ωcm, and furthermore, the volume resistivity may be 1.0 × 10⁻⁶ １０ The value may be less than Ωcm. This allows for effective discharge of static electricity accumulated on the optical sensor device, thereby reducing electrostatic discharge damage to the optical sensor device.

[0026] In the optical sensor component of this disclosure, the grain boundary phase primarily plays a role in reducing the volume resistivity. In the optical sensor component of this disclosure, the volume resistivity tends to decrease when the average grain size is large. This is presumed to be because the grain boundary phase network becomes thicker as the average grain size increases.

[0027] The optical sensor member disclosed herein may have a specific three-point bending strength of 260 MPa or more, and may also have a three-point bending strength of 300 MPa or more. This makes it possible to improve the strength of the optical sensor device.

[0028] Mechanical strength generally tends to be higher with smaller average grain sizes. Considering the balance between mechanical strength and volume resistivity, the average grain size may be in the range of 5 μm to 7 μm. The average grain size can be controlled by appropriately adjusting the firing temperature and firing time. Alternatively, the average grain size may be measured using the Code method.

[0029] Furthermore, by having a composition within the range described above, the optical sensor member disclosed herein can realize a black optical sensor member that is semiconductive and has excellent mechanical strength.

[0030] Furthermore, the optical sensor member disclosed herein, having a composition within the range described above, can exhibit semiconductivity even without a reducing atmosphere during firing. This allows for the easy manufacture of semiconducting optical sensor members, thereby reducing the manufacturing cost of optical sensor members.

[0031] Furthermore, the optical sensor member disclosed herein is Fe ２ TiO ５ Crystallized grains may be present in the grain boundary phase. Since such crystallized grains are black and semiconductive, the optical sensor component is more likely to become semiconductive.

[0032] Furthermore, the optical sensor member of this disclosure is a ＊ and b ＊ The value may be between -2.0 and 2.0. This provides an optical sensor component that is particularly suitable for applications requiring a black color.

[0033] Furthermore, each metal element constituting each metal oxide contained in the optical sensor member of this disclosure can be quantified using an ICP (Inductively Coupled Plasma) emission spectrometer. In this disclosure, for example, the content of each metal element obtained by measurement is converted to the content of each metal oxide to obtain the content rate of each metal oxide.

[0034] Specifically, for example, aluminum oxide is Al ２ O ３ Titanium dioxide is TiO ２ Iron oxide is Fe ２ O ３ Silicon oxide is SiO ２ Calcium oxide is converted to CaO, and magnesium oxide to MgO. If the optical sensor component contains other metallic elements, they should be converted to representative metallic oxides of those elements.

[0035] Next, an example of a method for manufacturing the optical sensor component of this disclosure will be described.

[0036] Particulate or powdered Al ２ O ３ , TiO ２ and Fe ２ O ３Mix the following, and use SiO as a sintering aid. ２ At least one of CaO and MgO is added. The particle size of each raw material powder may be, for example, 0.1 μm to 5 μm.

[0037] Then, water and an optional binder are added to each of the mixed powders and mixed and stirred. The resulting slurry is then granulated using a spray dryer, and a molded body of the desired shape is produced using these granules. By firing in an oxidizing atmosphere, the optical sensor member of the present disclosure is obtained. Known methods such as press molding can be used to produce the molded body.

[0038] The firing temperature may be, for example, between 1350°C and 1550°C. The firing time may be, for example, about 2 hours. The firing atmosphere may be air.

[0039] Optical sensor components with different compositions were fabricated, and the reflectance spectrum in the wavelength range of 200 nm to 2500 nm, volume resistivity, reflectance in the visible light region, and a ＊ , b ＊ In addition, the three-point bending strength, which represents mechanical strength, was measured.

[0040] First, Al ２ O ３ Powder and TiO ２ powder and Fe ２ O ３ Powder and SiO ２ We prepared powder, CaO powder, and MgO powder.

[0041] Furthermore, in sintered ceramics, aluminum oxide (Al ２ O ３ (conversion), iron oxide (Fe ２ O ３ (Conversion), Titanium Oxide (TiO) ２ (Conversion), silicon oxide (SiO ２ The weights were measured so that the mass ratios of calcium oxide (CaO equivalent) and magnesium oxide (MgO equivalent) matched the values ​​in Table 1.

[0042] Next, water and an optional binder were added to each weighed powder and mixed and stirred. The resulting slurry was then granulated using a spray dryer, and molded into the desired shape using these granules.

[0043] Next, sintered bodies for each sample were obtained by firing the molded bodies in a firing furnace under an atmospheric, i.e., oxidizing atmosphere. The firing temperature was in the range of 1350°C to 1550°C, and the firing time was 2 hours.

[0044] Samples No. 1-16 and 18-20 have a sintered surface. On the other hand, sample No. 17 is a sintered body with the same mass ratio as No. 16, but its sintered surface has been mirror-polished to an arithmetic mean roughness Ra of 0.03 μm or less.

[0045] Next, XRD measurements were performed on each sample to confirm the presence of aluminum oxide (alumina). Furthermore, the content of each element (Al, Si, Ca, Ti, Fe, and Mg) was determined using an ICP emission spectrometer. The content of each element was then converted from the determined elemental content to the content of each oxide, and the content of each element shown in Table 1 was calculated. Note that ICP emission spectrometry is sometimes simply referred to as ICP.

[0046] In addition, a sample of a conventional black aluminum oxide sintered body was also prepared. This sintered body is made of aluminum oxide (Al ２ O ３ (Conversion): 88.7% by mass, iron oxide (Fe ２ O ３ (Conversion): 1.2% by mass, Titanium Oxide (TiO) ２ (Conversion): 1.9% by mass, silicon oxide (SiO ２ (Conversion): 3.0 mass%, Magnesium oxide (MgO equivalent): 0.2 mass%, Cobalt oxide (Co ２ O ３ (Conversion): 0.3 mass%, chromium oxide (Cr ２ O ３ (Conversion): 1.4 mass%, manganese oxide (MnO) ２ (Conversion): It is composed of a mass ratio of 3.3% by mass.

[0047] In the present disclosure, this sintered body was used as Sample No. 21. Note that Sample No. 21 has a different composition from Samples No. 1 to 20, and thus is not described in Table 1.

[0048] Among the obtained sintered bodies, the reflectance spectra in the wavelength range of 200 nm to 2500 nm of Sample No. 16, Sample No. 17, and Sample No. 21 were measured using a commercially available spectrophotometer, for example, the ultraviolet-visible near-infrared spectrophotometer V-670 manufactured by JASCO Corporation.

[0049] Here, the integrating sphere unit used for the measurement of reflectance is ISN-723, the reference light source is a deuterium lamp for the region where the wavelength is from 185 nm to 340 nm and a halogen lamp for the region where the wavelength is from 340 nm to 2500 nm, and the measurement conditions are as follows: the measurement mode is total reflectance, the data acquisition interval is 1.0 nm, the UV / Vis bandwidth is 5.0 nm, and the NIR bandwidth is 20.0 nm. The results are shown in FIG. 1. FIG. 1 is a diagram showing the reflectance spectra in the wavelength range of 200 nm to 2500 nm of Sample No. 16, Sample No. 17, and Sample No. 21.

[0050] As shown in Sample Nos. 16 and 17 in FIG. 1, aluminum ２ O ３ in terms of conversion of 67% by mass or more of aluminum oxide, and TiO ２ in terms of conversion and Fe ２ O ３ in terms of conversion together being 10% by mass or more and 30% by mass or less, and TiO ２ / (TiO ２ +Fe ２ O ３ ) being 5% or more and 20% or less of titanium oxide and iron oxide, and SiO ２ in terms of conversion, CaO conversion, and MgO conversion together being 0.5% by mass or more and 3.0% by mass or less of a sintering aid. The optical sensor member containing these has a reflectance of 25% or less at all wavelengths in the wavelength range of 500 nm to 2500 nm, regardless of whether it is the baked skin surface or the mirror surface.

[0051] On the other hand, as shown in sample No. 21 in Figure 1, the photosensor member that fell outside at least one of the above compositional ranges had wavelengths with reflectivity exceeding 25% in the burnt surface in the wavelength range of 500 nm to 2500 nm.

[0052] Furthermore, as shown in sample No. 17 of Figure 1, by making the surface of the optical sensor member a mirror surface, the reflectance was further reduced at all wavelengths in the wavelength range of 500 nm to 2500 nm compared to when the surface of the optical sensor member was a burnt surface.

[0053] Furthermore, in samples No. 16 and No. 17 of Figure 1, the ratio of the reflectance at a wavelength of 2500 nm to the reflectance at a wavelength of 500 nm was 115% and 81%, respectively. In contrast, in sample No. 21 of Figure 1, for example on the mirror surface, the ratio of the reflectance at a wavelength of 2500 nm to the reflectance at a wavelength of 500 nm was 559%.

[0054] Furthermore, the volume resistivity of the obtained sintered body was measured using a three-terminal method with a commercially available electrical resistance meter, such as the HIOKI DSM-8104 super-insulation resistance meter, and the results are shown in Table 1.

[0055] Furthermore, the reflectance in the visible light region of the obtained sintered body was measured in the visible light region using a colorimeter, such as a Konica Minolta CR-13, and the results are shown in Table 1.

[0056] Furthermore, using the obtained sintered body, CIE1976(L) is performed in accordance with JIS Z 8722-2009. ＊ a ＊ b ＊ ) a based on color space ＊ and b ＊ These were measured using a spectrophotometer, for example, a Konica Minolta CM-700d, at wavelengths of 400 nm to 700 nm, and a ＊ and b ＊ The measurement results are shown in Table 1. Note that all percentages in Table 1, except for reflectance, represent mass percent.

[0057] Furthermore, the three-point bending strength was measured using the obtained sintered body in accordance with JIS R 1601-2008, and the results are shown in Table 1.

[0058] Note that the measurements for each sample shown in Table 1 are for the burnt surface, except for sample No. 17, which is the measurement for the mirror surface of sample No. 17, which has the same composition as sample No. 16.

[0059]

[0060] As shown in sample No. 1, TiO ２ Conversion and Fe ２ O ３ If the combined amount of titanium dioxide and iron oxide is less than 10% by mass, the volume resistivity will be 1.0 × 10⁻⁶. １１ A light sensor component with a conductivity greater than Ωcm and poor semiconductivity was obtained.

[0061] Furthermore, as shown in sample No. 6, TiO ２ Conversion and Fe ２ O ３ When the combined amount of titanium oxide and iron oxide exceeds 30% by mass, the three-point bending strength is less than 260 MPa, resulting in an optical sensor component with poor mechanical strength.

[0062] Furthermore, as shown in sample No. 7, TiO ２ / (TiO ２ +Fe ２ O ３ If the ratio is less than 5%, the volume resistivity is 1.0 × 10 １１ A light sensor component with a conductivity greater than Ωcm and poor semiconductivity was obtained.

[0063] Also, as shown in sample No. 12, TiO ２ / (TiO ２ +Fe ２ O ３ If ) exceeds 20%, a ＊ The value was greater than 2.0, resulting in a light sensor component with poor black coloration.

[0064] Also, as shown in sample No. 13, SiO ２ If the sintering aid is contained in a total of less than 0.5% by mass, calculated on a conversion basis, CaO basis, and MgO basis, the volume resistivity is 1.0 × 10⁻⁶. １１ A light sensor component with a conductivity greater than Ωcm and poor semiconductivity was obtained.

[0065] Sample No. 18, which contained magnesium oxide, showed higher strength than sample No. 19, which did not contain magnesium oxide. Upon microstructural examination, the average grain size of sample No. 18 was 4.6 μm, which was smaller than that of sample No. 19, which had an average grain size of 5.1 μm. The average grain sizes of samples No. 2-5, 8-11, and 14-19 were all within the range of 5 μm to 7 μm.

[0066] Also, as shown in sample No. 20, SiO ２ If the sintering aid is contained in a total of more than 3.0% by mass, calculated on a convertible basis, on a CaO basis, and on a MgO basis, the reflectance is more than 15%, and a ＊ and b ＊ The value was less than -2.0, resulting in a light sensor component with poor black coloration.

[0067] Furthermore, the three-point bending strength of sample No. 20 was less than 260 MPa, resulting in a light sensor component with poor mechanical strength.

[0068] In contrast, as shown in samples No. 2-5, 8-11, and 14-19, Al ２ O ３ Aluminum oxide of 67% by mass or more, and TiO ２ Conversion and Fe ２ O ３ The total amount is between 10% by mass and 30% by mass, and TiO ２ / (TiO ２ +Fe ２ O ３ Titanium oxide and iron oxide having a concentration of 5% or more and 20% or less, and SiO ２ A photosensor component containing a sintering aid that totals 0.5% by mass or more and 3.0% by mass or less in terms of conversion, CaO conversion, and MgO conversion has a volume resistivity of 1.0 × 10 ４ Ωcm or greater and 1.0 × 10 １１ The coefficient of force was less than or equal to Ωcm, and the three-point bending strength was 260 MPa or higher.

[0069] Thus, the optical sensor member of the present disclosure has good semiconductivity and physical strength. Furthermore, the optical sensor member of the present disclosure has a reflectance of 15% or less, a ＊ and b ＊The value was between -2.0 and 2.0, and exhibited a black color.

[0070] Furthermore, the aluminum oxide content is Al ２ O ３ When the volume resistivity was 89.5% by mass or less, a photosensor component with low volume resistivity was obtained.

[0071] Although the present disclosure has been described in detail above, this disclosure is not limited to the embodiments described above, and various modifications and improvements are possible without departing from the gist of this disclosure.

[0072] Further effects and modifications can be readily derived by those skilled in the art. Therefore, broader aspects of the present invention are not limited to the specific details and representative embodiments expressed and described above. Accordingly, various modifications are possible without departing from the spirit or scope of the overall concept of the invention as defined by the appended claims and their equivalents.

[0073] Furthermore, this technology can also take the following configurations: (1) A light sensor member containing aluminum oxide, titanium oxide, iron oxide, and a sintering aid, but not containing cobalt oxide, chromium oxide, or manganese oxide, and having a reflectance of 25% or less at all wavelengths in the wavelength range of 500 nm to 2500 nm. (2) The light sensor member according to (1), wherein the ratio of the reflectance at a wavelength of 2500 nm to the reflectance at a wavelength of 500 nm is 50% to 200%. (3) The aluminum oxide is Al ２ O ３ It contains 67% by mass or more in terms of conversion, and the titanium dioxide and the iron oxide are TiO ２ Conversion and Fe ２ O ３ It contains a total of 10% or more by mass and 30% or less by mass, and TiO ２ / (TiO ２ +Fe ２ O ３(1) or (2) above, wherein the amount of the sintering aid is 5% or more and 20% or less, and the sintering aid is contained in an amount of 0.5% or more and 3.0% or less by mass. (4) The optical sensor member according to any one of (1) to (3) above, wherein the surface is mirror-finished. (5) The volume resistivity is 1.0 × 10 ４ Ωcm or greater and 1.0 × 10 １１ (6) An optical sensor member according to any one of (1) to (4) above, having a density of Ωcm or less.

Claims

1. An optical sensor component containing aluminum oxide, titanium oxide, iron oxide, and a sintering aid, but not containing cobalt oxide, chromium oxide, or manganese oxide, and having a reflectance of 25% or less at all wavelengths in the wavelength range of 500 nm to 2500 nm.

2. The optical sensor member according to claim 1, wherein the ratio of the reflectance at a wavelength of 2500 nm to the reflectance at a wavelength of 500 nm is 50% to 200%.

3. The aluminum oxide contains 67% by mass or more in terms of Al ２ O ３ , the titanium oxide and the iron oxide contain a total of 10% by mass or more and 30% by mass or less in terms of TiO ２ and Fe ２ O ３ , TiO ２ / (TiO ２ + Fe ２ O ３ ) is 5% or more and 20% or less, and the sintering aid contains 0.5% by mass or more and 3.0% by mass or less. The photosensor member according to claim 1 or 2.

4. The optical sensor member according to any one of claims 1 to 3, wherein the surface is mirror-like.

5. Volume resistivity is 1.0 × 10⁻⁶ ４ Ωcm or greater and 1.0 × 10 １１ The optical sensor member according to any one of claims 1 to 4, wherein the value is Ωcm or less.

6. An optical sensor device comprising the optical sensor member described in any one of claims 1 to 5.

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