WO2020253535A1 - 具有温度补偿效应的滤光片和传感器系统 - Google Patents

具有温度补偿效应的滤光片和传感器系统 Download PDF

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WO2020253535A1
WO2020253535A1 PCT/CN2020/094169 CN2020094169W WO2020253535A1 WO 2020253535 A1 WO2020253535 A1 WO 2020253535A1 CN 2020094169 W CN2020094169 W CN 2020094169W WO 2020253535 A1 WO2020253535 A1 WO 2020253535A1
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Prior art keywords
filter
refractive index
temperature
optical filter
temperature compensation
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PCT/CN2020/094169
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English (en)
French (fr)
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于光龙
苏炎
刘哲
李昱
林志强
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福州高意光学有限公司
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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/20—Filters
    • G02B5/28—Interference filters
    • G02B5/285—Interference filters comprising deposited thin solid films
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
    • G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
    • G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
    • G01D5/266—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light by interferometric means
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/20—Filters
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/20—Filters
    • G02B5/28—Interference filters

Definitions

  • the invention relates to the field of optical filters, in particular to optical filters with temperature compensation that can be applied to environmental monitoring, infrared imaging, 3D recognition, lidar or other imaging applications.
  • VCSEL vertical cavity surface emitting lasers
  • the filter at the receiver is also an important component of the sensor system.
  • the filter passes the light of the laser light source (ie signal light) and blocks the light outside the laser light source (ie noise), which has a decisive effect on the signal-to-noise ratio of the system.
  • One of the key indicators of the filter is bandwidth. The wider the bandwidth of the filter, the easier the light from the laser light source can pass through, but the more noise it transmits. If the bandwidth of the filter is too narrow, although the noise can be effectively filtered, the laser may be partially blocked. Therefore, the selection of filter bandwidth needs to be comprehensively considered based on factors such as light source characteristics, optical path design, and filter processing capabilities.
  • the existing sensor systems respond to the following methods: 1) Control the temperature of the laser light source so that the laser can work stably at a certain temperature; 2)
  • the film system is designed with a specific material structure, so that the performance of the filter is as good as temperature changes. It may not be sensitive; 3) Increase the bandwidth of the filter so that the passband of the filter can cover the working wavelength of the laser at the high temperature and low temperature working limit.
  • method 1) significantly increases the cost and power consumption of the sensor system;
  • method 2) is the current mainstream method, and also significantly increases the complexity and cost of the filter manufacturing process;
  • method 3) does not increase the cost, but makes The bandwidth of the filter is wider, and more non-signal light will pass through when working at room temperature, which sacrifices the signal-to-noise ratio and performance of the sensor when working at room temperature.
  • the present invention has made technical improvements to the existing applied filters, and its purpose is to provide a temperature compensation filter and sensor system with the function of temperature compensation for the temperature drift of the laser light source .
  • An optical filter with a temperature compensation effect which has a partially overlapping pass band in the wavelength range of 800 nm to 1800 nm, and includes a substrate and a filter film layer plated on the surface of the substrate, and the filter film layer includes a plurality of high refractive index Layer and multiple low-refractive index layers;
  • the material for the high-refractive index layer includes at least Si:H or Ge:H, where the high-refractive index layer made of Si:H material has a refractive index in the wavelength range of 800nm to 1800nm
  • the refractive index of the high refractive index layer made of Ge:H material is greater than 4 in the wavelength range of 800nm to 1800nm; the refractive index of the low refractive index layer is less than 3 in the wavelength range of 800nm to 1800nm;
  • the pass band of the filter has a center wavelength.
  • the temperature drift coefficient of the center wavelength is greater than 0.04 nm/degree Celsius and less than 0.4 nm/degree Celsius.
  • the thermal expansion coefficient of the material of the substrate is a positive number and not more than 30 ppm/degree Celsius.
  • the substrate is made of silicon material, fused silica, SiO2-based glass, tempered glass, colored glass, sapphire, polymethylmethacrylate or polycarbonate.
  • the low refractive index layer is made of at least one of TiO 2 , Nb 2 O 5 , Ta 2 O 5 , SiO 2 , MgF 2 or Si x N y .
  • the filter is an interference filter.
  • the interference filter is a multi-cavity bandpass filter and the number of cavities is more than three.
  • a sensor system which includes:
  • the pass band includes the center wavelength of the light source
  • a semiconductor laser whose emission wavelength is in the wavelength range of 800nm to 1800nm, and its emission spectrum has a center wavelength and the temperature drift coefficient of the center wavelength is greater than 0.04nm/degree Celsius and less than 0.4nm/degree Celsius;
  • the detector is used to receive the light emitted by the semiconductor laser, and the position of the detector in the optical path is behind the filter.
  • the difference between the temperature drift coefficient of the center wavelength of the filter and the temperature drift coefficient of the center wavelength of the semiconductor laser is less than 0.05 nm/degree Celsius.
  • the present invention has the beneficial effects compared with the prior art: this solution can maintain a small filter bandwidth while widening the sensor's operating temperature range, which is beneficial to improve the signal-to-noise of the system. ratio.
  • the key of the present invention is to design suitable film materials and ratios, and design suitable substrate materials, so that the filter can obtain a temperature drift coefficient close to the corresponding laser light source, thereby achieving the effect of temperature compensation.
  • Figure 1 is a schematic diagram of the filter of the present invention
  • FIG. 2 is a schematic diagram of the relationship between the temperature coefficient of the normalized refractive index of the film and the temperature drift coefficient of the center wavelength of the filter according to the scheme of the present invention
  • Figure 3 is a list of typical values of refractive index temperature coefficients of conventional coating materials and Si:H and Ge:H materials;
  • FIG. 4 is a schematic diagram of the relationship between the thermal expansion coefficient of the substrate material of the present invention and the temperature drift coefficient of the center wavelength of the filter;
  • Figure 5 shows the emission wavelength specification of an example VCSEL laser
  • FIG. 6 is a comparison list of the conventional filter matching the laser in FIG. 5 and the filter according to the present invention.
  • FIG. 7 is a transmission spectrum of a conventional filter matching the laser in FIG. 5, and a normalized spectrum of the laser;
  • Fig. 9 is a schematic diagram of a sensor system based on the present invention.
  • the optical filter 101 with temperature compensation effect of the present invention has a partially overlapping pass band in the wavelength range of 800 nm to 1800 nm, and includes a substrate 102 and a filter film layer 103 plated on the surface of the substrate 102.
  • the filter film layer 103 includes multiple high refractive index layers and multiple low refractive index layers stacked; the total number of layers included in the filter film layer 103 in this embodiment is n, specifically 103-1 Layer, 103-2 layer, 103-3 layer up to 103-n layer, these layers include multiple high refractive index layers and multiple low refractive index layers.
  • the material made of the high refractive index layer includes at least Si:H or Ge:H, and the high refractive index layer made of Si:H material has a refractive index greater than 3 in the wavelength range of 800nm to 1800nm.
  • the refractive index of the high refractive index layer made of H material is greater than 4 in the wavelength range of 800 nm to 1800 nm; the refractive index of the low refractive index layer is less than 3 in the wavelength range of 800 nm to 1800 nm.
  • the filter 101 is based on the principle of optical interference, through the stacking of multilayer films, to achieve the purpose of selectively transmitting specific wavelengths and blocking other wavelengths.
  • the substrate material 102 can be made of optical glass such as BK7, K9, D263T, etc., with good transmittance to the light source wavelength band, or silicon material, fused silica, tempered glass, colored glass, sapphire, polymethyl methacrylate or polycarbonate Wait.
  • FIG. 1 schematically places the filter film layer on one surface of the substrate material 102, but in fact, both the front and back surfaces of the substrate material 102 can be coated with the filter film layer.
  • the filter can obtain a temperature drift coefficient close to the corresponding laser light source, thereby achieving the effect of temperature compensation.
  • the film material contains Si:H or Ge:H material, which is the key to the temperature compensation of the present invention.
  • the center wavelength of the bandpass filter is affected by the ambient temperature.
  • the specific mechanism is that the temperature change affects the filter:
  • the volume change of the substrate material is mainly manifested as contraction and extension in the plane direction
  • the current industry's optical filter deposition process is generally ion-assisted deposition or sputtering process. This kind of process itself has a relatively high film-forming density (close to a bulk material), and its performance is hardly affected by water vapor adsorption or release.
  • the temperature effects are mainly 2), 5), and 6).
  • the current mainstream optical filters, whose temperature characteristic optimization is mainly focused on suppressing the influence of temperature on the center wavelength, and the optical filter of the present invention, based on a reasonable material design, can achieve temperature drift characteristics very close to that of a semiconductor laser, thereby achieving The effect of temperature compensation.
  • Figure 2 shows a schematic diagram of the relationship between the temperature coefficient of the normalized refractive index of the film and the temperature drift coefficient of the center wavelength of the filter. Since the film layer is composed of multiple materials superimposed, the material ratio also affects the normalized refractive index temperature coefficient. When the film layer is composed of high refractive index material H and low refractive index material L, the film layer is unified
  • the temperature coefficient of refractive index is described by the following equation:
  • ⁇ is the normalized refractive index temperature coefficient of the film
  • ⁇ H and ⁇ L are the refractive index temperature coefficients of the high refractive index material and the low refractive index material, respectively
  • a and b are the proportion weights of the two materials.
  • the higher the temperature coefficient of the refractive index of the film material the more sensitive the center wavelength of the filter is to temperature; after calculation, if the temperature drift coefficient of the filter is 0.04nm/degrees Celsius to 0.4nm/degrees Celsius
  • the coating material must be much larger than the existing conventional coating material.
  • Figure 3 is a list of typical values of the refractive index temperature coefficients of conventional coating materials and Si:H and Ge:H materials.
  • Si:H and Ge:H are higher than conventional coating materials such as Ta 2 O 5 , SiO 2 , and Nb.
  • the temperature coefficient of refractive index of 2 O 5 , Si 3 N 4 , and TiO 2 is one to two orders of magnitude larger, which is suitable for the film system design of the filter with a temperature drift coefficient of 0.04nm/degree Celsius to 0.4nm/degree Celsius.
  • the film design preferably uses Si:H; if matching high power diodes and arrays (typical temperature drift coefficient of 0.3nm/degree Celsius), the film design is preferred Use Ge:H.
  • the thermal expansion coefficient of the substrate material also has an important influence on the temperature drift coefficient of the filter.
  • the shape change of the substrate material will drive the expansion or contraction of the film material, and cause the change of the substrate-film interface stress.
  • Figure 4 shows a schematic diagram of the relationship between the thermal expansion coefficient of the substrate material and the temperature drift coefficient of the center wavelength of the filter. Choosing a substrate material with a low expansion coefficient is conducive to obtaining a larger temperature drift coefficient of the filter. It should be noted that when the temperature is higher than a certain level (such as greater than 200 degrees Celsius), an irreversible release process of the substrate-film interface stress will occur, resulting in an irreversible change in the center wavelength of the filter. But in the working environment of conventional sensor system (generally less than 100 degrees), the possibility of this happening is very small.
  • Figure 5 shows the emission wavelength specifications of an example VCSEL laser.
  • This laser is a typical light source for 3D face recognition, limited by the consistency of the manufacturing process, its center wavelength consistency is 940 ⁇ 8nm (at 20 degrees Celsius), the typical spectral width is 2nm, and the laser center wavelength temperature drift coefficient It is 0.07nm/degree Celsius, and the design operating temperature is -20 degrees Celsius to 80 degrees Celsius. Based on the above specifications, the wavelength range of the laser when operating at -20 degrees Celsius is:
  • the wavelength range of the laser at 80 degrees Celsius is:
  • Fig. 6 is a comparison table of a conventional filter matching the laser in Fig. 5 and the filter according to the present invention.
  • Example Conventional filters aim at suppressing the temperature drift of the filter itself, choose Ta 2 O 5 , SiO 2 whose refractive index is the least sensitive to temperature as coating materials, and choose WMS-15 material with larger thermal expansion coefficient as substrate material , The filter designed by this material combination is optimized through the design of the film system, and the center wavelength is It can be considered that the temperature drift coefficient is approximately equal to zero.
  • Example The 90% T passband wavelength of the conventional filter needs to cover the output wavelength range of the laser in FIG. 5, that is, the minimum value is 928.2 nm, the maximum value is 953.2 nm, and the filter bandwidth is designed to be 25 nm.
  • Si:H and SiO 2 are designed as coating materials, and BK7 material with ordinary thermal expansion coefficient is designed as substrate material, and the film material ratio is optimized through the film system design to achieve a center wavelength temperature drift coefficient of 0.045 nm/Celsius.
  • the temperature drift coefficient is close to that of the laser, and the difference in temperature drift coefficient is:
  • the bandwidth of the exemplary filter of the present invention can be significantly narrowed, and the design passband range at 20 degrees Celsius is:
  • Fig. 7 is a transmission spectrum of a conventional filter matching the laser in Fig. 5, and a normalized spectrum of the laser
  • Fig. 8 is a transmission spectrum of a filter of the present invention matching the laser in Fig. 5, and a laser normalization ⁇ Spectrogram.
  • the example of a conventional filter the center wavelength of the filter is extremely temperature-insensitive, and the design bandwidth is 25nm; the 90% T starting wavelength of the filter is close to the working wavelength of the laser at low temperature, and the 90% T ending wavelength is close to the high temperature of the laser The working wavelength.
  • the optical filter has a temperature compensation effect, and the design bandwidth can be narrowed to 20.5 nm; when the temperature rises, the center wavelength of the filter and the laser simultaneously shift to long wavelength; when the temperature drops , The center wavelength of the filter and the laser drifts to shortwave at the same time; at the extreme operating temperature, the passband of the filter can still cover the laser output wavelength at that temperature.
  • the bandwidth of the filter is proportional to the noise of the sensor system
  • the filter of the present invention the signal-to-noise ratio is increased by 18%, which has a significant improvement effect.
  • the filter bandwidth also needs to consider many factors such as process tolerance, filter transition band jitter, etc.
  • the filter of the present invention still has obvious temperature compensation effects , To obtain a better signal-to-noise ratio of the sensing system.
  • the optical filter of the present invention can improve the performance of the sensor system.
  • FIG. 9 is a schematic diagram of the sensor system based on the present invention, where 601 is the sensor system of the present invention.
  • 602 is a semiconductor laser located at the emitting end of the sensor. Its emission wavelength is in the 800-1800nm wavelength range. Its emission spectrum has a center wavelength, and the temperature drift coefficient of the center wavelength is greater than 0.04nm/degrees Celsius and less than 0.4nm/degrees Celsius.
  • the transmitting end also includes a beam shaping device 604, which is used for collimating, focusing, or forming a spot pattern of the emitted beam.
  • the laser light emitted by the semiconductor laser 602 is irradiated on the detected object 607 after passing through the beam shaping device 604.
  • the reflected light returns through the lens group 605 and the filter 606 based on the present invention, and reaches the detector 603.
  • the detector 603 is located behind the filter 606 of the present invention in the optical path.
  • the filter 606 may be before the lens group 605 or after the lens group 605 in the optical path.
  • the difference between the temperature drift coefficient of the center wavelength of the filter 606 and the temperature drift coefficient of the center wavelength of the semiconductor laser 602 is less than 0.05 nm/degree Celsius, and the filter has a good temperature compensation effect.

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  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
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Abstract

一种具有温度补偿效应的滤光片(101)和传感器系统(601)，滤光片(101)包括基板(102)以及镀制在基板(102)表面的滤光膜层(103)，滤光膜层(103)包括多个高折射率层和多个低折射率层；其中，由Si∶H材料制成的高射折率层在波长范围为800nm到1800nm的折射率均大于3，由Ge∶H材料制成的高射折率层在波长范围为800nm到1800nm的折射率均大于4；低折射率层在波长范围为800nm到1800nm的折射率均小于3。由于在拓宽传感器工作温度范围的同时，可以维持较小的滤光片(101)带宽，有利于提高系统的信噪比。通过设计合适的滤光膜层(103)材料及配比和设计合适的基板(102)材料，使得滤光片(101)获得和对应激光光源接近的温漂系数，从而实现温度补偿的效果。

Description

具有温度补偿效应的滤光片和传感器系统 技术领域
本发明涉及滤光片领域，尤其涉及可应用于环境监测、红外成像、3D识别、激光雷达或其他成像领域应用的具有温度补偿效应的滤光片。
背景技术
随着3D传感，汽车激光雷达等领域的爆发，半导体激光器从光通信领域走向消费电子领域。特别是以垂直腔面发射激光器(VCSEL)代表的半导体激光器，有阈值电流低、发散角小、易调制、易集成等优点，在红外传感领域获得了广泛的应用。
除了发射端的半导体激光器外，接收端的滤光片也是传感器系统的重要组件。滤光片通过激光光源的光(即信号光)，阻止激光光源之外的光(即噪声)，对系统的信噪比有决定性作用。滤光片的关键指标之一是带宽。滤光片带宽越宽，激光光源的光越容易透过，但同时透过的噪声也越多；若滤光片带宽过窄，虽然噪声可以有效过滤，但有可能激光被部分阻隔。因此，滤光片带宽的选取，需要基于光源特点、光路设计、滤光片加工能力等因素综合考虑。
相比于固体激光器或气体激光器，半导体激光器的一个显著特点是其输出波长具有较明显的温度漂移。因此，对于要求一定温度范围内都能正常工作的传感器系统，其系统设计必须要考虑高温或低温工作极限的情况。
现有的传感器系统的应对方法有：1)对激光光源进行控温，使激光器可以稳定在某个温度附近工作；2)膜系设计采用特定材料的结构，使滤光片性能对温度变化尽可能不敏感；3)增加滤光片的带宽，使滤光片的通带可以覆盖激光器在高温、低温工作极限时的工作波长。其中，方法1)显著提高了传感器系统的成本和功耗；方法2)是当前的主流方法，也显著提高了滤光片制造工艺的复杂度和成本；方法3)不会提高成本，但使得滤光片的带宽更宽，在常温工作时会透过更多的非信号光，牺牲了传感器常温工作时的信噪比和性能。
发明内容
针对现有技术的情况，本发明对现有应用的滤光片进行了技术改进，其目的在于提供一种对激光光源温度漂移进行温度补偿的功能的具有温度补偿效应的滤光片和传感器系统。
为了实现上述的技术目的，本发明采用的技术方案为：
具有温度补偿效应的滤光片，其具有800nm到1800nm波长范围部分重叠的通带，其包括基板以及镀制在基板表面的滤光膜层，所述的滤光膜层包括多个高折射率层和多个低折射率层；制成高折射率层的材料至少包括Si∶H或Ge∶H，其中，由Si∶H材料制成的高射折率层在波长范围为800nm到1800nm的折射率均大于3，由Ge∶H材料制成的高射折率层在波长范围为800nm到1800nm的折射率均大于4；低折射率层在波长范围为800nm到1800nm的折射率均小于3；
所述滤光片的通带具有中心波长，当工作环境温度范围为-40摄氏度到120摄氏度温度范围部分重叠时，其中心波长的温度漂移系数大于0.04nm/摄氏度且小于0.4nm/摄氏度。
进一步，所述基板的材料热膨胀系数为正数且不大于30ppm/摄氏度。
进一步，所述的基板为硅材料、熔融石英、基于SiO2的玻璃、钢化玻璃、有色玻璃、蓝宝石、聚甲基丙烯酸甲酯或聚碳酸酯制成。
进一步，所述的低折射率层为TiO 2、Nb 2O 5、Ta 2O 5、SiO 2、MgF 2或Si xN y中的至少一种制成。
进一步，所述的滤光片为干涉滤光片。
进一步，所述的干涉滤光片为多腔式带通滤光片且其腔的数目为3个以上。
一种传感器系统，其包括：
上述所述的滤光片，其通带包含光源的中心波长；
半导体激光器，其发光波长位于800nm～1800nm波长范围内，其发射光谱具有中心波长且中心波长的温度漂移系数大于0.04nm/摄氏度并小于0.4nm/摄氏度；
探测器，用于接收半导体激光器发出的光，探测器在光路中的位置位于滤光片之后。
进一步，所述滤光片中心波长的温度漂移系数和所述半导体激光器中心波长的温度漂移系数的差值小于0.05nm/摄氏度。
采用上述的技术方案，本发明与现有技术相比，其具有的有益效果为：本方案在拓宽传感器工作温度范围的同时，可以维持较小的滤光片带宽，有利于提高 系统的信噪比。另外，本发明的关键在于，通过设计合适的膜层材料及配比，和设计合适的基板材料，使得滤光片获得和对应激光光源接近的温漂系数，从而实现温度补偿的效果。
附图说明
下面将结合附图和具体实施方式做本发明方案进行详细说明。
图1为本发明方案滤光片的简要示意图；
图2为本发明方案的膜层归一化折射率温度系数和滤光片中心波长温漂系数关系的示意图；
图3为常规镀膜材料和Si:H、Ge:H材料的折射率温度系数典型值的列表；
图4为本发明基板材料热膨胀系数和滤光片中心波长温漂系数关系的示意图；
图5为某示例的VCSEL激光器的发射波长规格；
图6为匹配图5中的激光器的常规滤光片和根据本发明的滤光片进行的比较列表；
图7为匹配图5中的激光器的常规滤光片的透射光谱，及激光器归一化光谱图；
图8为匹配图5中的激光器的本发明的滤光片的透射光谱，及激光器归一化光谱图；
图9是基于本发明的传感器系统的示意图。
具体实施方式
如图1所示，本发明具有温度补偿效应的滤光片101，其具有800nm到1800nm波长范围部分重叠的通带，其包括基板102以及镀制在基板102表面的滤光膜层103，所述的滤光膜层103包括多个高折射率层和多个低折射率层堆叠而成；本实施例中的滤光片膜层103包含的总层数为n，具体分别为103-1层、103-2层、103-3层直至103-n层，这些膜层包含了多个高折射率层和多个低折射率层。其中，制成高折射率层的材料至少包括Si∶H或Ge∶H，其中，由Si∶H材料制成的高射折率层在波长范围为800nm到1800nm的折射率均大于3，由Ge∶H材料制成的高射折率层在波长范围为800nm到1800nm的折射率均大于4；低折射率层在波长范围为800nm到1800nm的折射率均小于3。本实施例中滤光 片101基于光学干涉原理，通过多层膜的堆叠，实现对特定波长选择性的透过，对其他波长进行阻隔的目的。基板材料102可以使用对光源波段透过性良好的光学玻璃如BK7、K9、D263T等，也可以是硅材料、熔融石英、钢化玻璃、有色玻璃、蓝宝石、聚甲基丙烯酸甲酯或聚碳酸酯等。图1示意性的将滤光片膜层放置在了基板材料102的一个面上，但实际上基板材料102的前后两个表面都可以镀制滤光膜层。
本发明通过设计合适的膜层材料及配比，和设计合适的基板材料，使得滤光片获得和对应激光光源接近的温漂系数，从而实现温度补偿的效果。其中，膜层材料包含Si:H或Ge:H材料，是本发明实现温度补偿的关键。
以下就本发明的实现方式和工作原理进行说明。
基于干涉原理的带通滤光片，其中心波长受环境温度影响，其具体机理在于温度变化影响了滤光片的：
1)膜层材料的堆积密度变化
2)膜层材料的折射率变化
3)由膜层材料热膨胀/收缩导致的膜层体积变化
4)膜层材料内部孔洞中的水汽的释放和吸附
5)基板材料的体积变化，主要表现为在平面方向的收缩和延伸
6)基片-膜层界面应力(substrate-induced stress)变化，进一步导致膜层受基板抑制而产生形变(volumetric distortion)
目前业内的滤光片沉积工艺一般为离子辅助沉积或溅射工艺，这类工艺本身的成膜堆积密度较高(接近块状材料)，性能几乎不会受到水汽吸附或释放的影响。对于目前常规的滤光片，温度影响中主要为2)、5)、6)三项。目前主流的滤光片，其温度特性优化主要集中在于抑制温度对中心波长的影响，而本发明的滤光片，基于合理的材料设计，可实现和半导体激光器十分接近的温度漂移特性，从而实现温度补偿的效果。更具体的，图2给出了膜层归一化折射率温度系数和滤光片中心波长温漂系数关系的示意图。由于膜层由多种材料叠加组成，材料配比对归一化折射率温度系数也产生影响，当膜层由高折射率材料H、低折射率材料L两种材料构成时，膜层归一化折射率温度系数由如下方程描述：
δ＝(aδ H+bδ L)/(a+b)
其中δ为膜层归一化折射率温度系数，δ H、δ L分别为高折射率材料、低折射率材料的折射率温度系数，a、b为两种材料的配比权重。在其他条件不变的情况下，膜层材料的折射率温度系数越高，滤光片中心波长对于温度越敏感；经计算，若获得温漂系数在0.04nm/摄氏度到0.4nm/摄氏度的滤光片，其镀膜材料必须远大于现有常规镀膜材料。图3为常规镀膜材料和Si:H、Ge:H材料的折射率温度系数典型值的列表，可以看出，Si:H和Ge:H比常规镀膜材料如Ta 2O 5、SiO 2、Nb 2O 5、Si 3N 4、TiO 2的折射率温度系数大一到两个数量级，适合用于0.04nm/摄氏度到0.4nm/摄氏度温漂系数的滤光片的膜系设计。更进一步的，若匹配VCSEL激光器(典型温漂系数0.07nm/摄氏度)，膜系设计优选使用Si:H；若匹配高功率二极管及阵列(典型温漂系数0.3nm/摄氏度)，膜系设计优选使用Ge:H。
基板材料的热膨胀系数对滤光片的温漂系数也有重要影响。在温度变化过程中，基板材料的形状变化会带动膜层材料的伸展或收缩，并引起基片-膜层界面应力的变化。图4给出了基板材料热膨胀系数和滤光片中心波长温漂系数关系的示意图。选用低膨胀系数的基板材料，有利于获得较大的滤光片温漂系数。需要注意的是，当温度高于一定水平(如大于200摄氏度)，会产生基片-膜层界面应力的不可逆的释放过程，导致滤光片中心波长有不可逆的变化。但在常规传感器系统工作环境中(一般小于100度)，这种情况发生的可能性很小。
以下以某VCSEL规格为示例，对本发明的实施例进行比较说明。图5为某示例的VCSEL激光器的发射波长规格。该激光器为典型的用于3D人脸识别的光源，受限于制程的一致性，其中心波长一致性为940±8nm(20摄氏度时)，典型的光谱宽度为2nm，激光器中心波长温度漂移系数为0.07nm/摄氏度，设计工作温度为-20摄氏度到80摄氏度。基于以上规格，该激光器在-20摄氏度工作时的波长范围为：
Figure PCTCN2020094169-appb-000001
Figure PCTCN2020094169-appb-000002
该激光器在80摄氏度工作时的波长范围为：
Figure PCTCN2020094169-appb-000003
Figure PCTCN2020094169-appb-000004
基于以上光谱范围，开展滤光片的规格分析和设计。图6为匹配图5中的激 光器的常规滤光片和根据本发明的滤光片进行的比较列表。示例常规滤光片以抑制滤光片本身温度漂移为目的，选用折射率对温度最不敏感的Ta 2O 5、SiO 2作为镀膜材料，并选用较大热膨胀系数的WMS-15材料作为基板材料，该材料组合设计的滤光片，通过膜系设计优化，中心波长温漂
Figure PCTCN2020094169-appb-000005
可以认为温漂系数约等于0。示例常规滤光片的90％T通带波长需要覆盖图5的激光器的输出波长范围，即最小值928.2nm、最大值953.2nm，滤光片带宽设计为25nm。
利用本发明的示例滤光片，设计Si:H和SiO 2作为镀膜材料，并设计普通热膨胀系数的BK7材料作为基板材料，通过膜系设计优化膜料配比，实现中心波长温漂系数为0.045nm/摄氏度。该温漂系数与激光器的温漂系数接近，温漂系数的差值为：
Figure PCTCN2020094169-appb-000006
考虑到激光器中心波长的温漂大部分都被滤光片温漂补偿，利用本发明的示例滤光片，其带宽可以明显收窄，在20摄氏度时的设计通带范围为：
Figure PCTCN2020094169-appb-000007
Figure PCTCN2020094169-appb-000008
图7为匹配图5中的激光器的常规滤光片的透射光谱，及激光器归一化光谱图；图8为匹配图5中的激光器的本发明的滤光片的透射光谱，及激光器归一化光谱图。示例的常规滤光片，滤光片中心波长对温度极不敏感，设计带宽为25nm；滤光片的90％T起始波长接近激光器低温时的工作波长，90％T终止波长接近激光器高温时的工作波长。而利用本发明的示例滤光片，滤光片具有温度补偿效应，设计带宽可收窄至20.5nm；当温度升高时，滤光片和激光器的中心波长同时向长波漂移；当温度下降时，滤光片和激光器的中心波长同时向短波漂移；在极限工作温度时，滤光片的通带仍能覆盖该温度时的激光器输出波长。由于滤光片带宽和传感器系统的噪声呈正比关系，采用本发明的滤光片，信噪比提升了18％，具有明显的改善效果。在实际生产时，滤光片带宽还需要考虑制程公差、滤光片过渡带抖度等多个因素，但在同样制程工艺能力情况下，采用本发明的滤光片仍具有明显的温度补偿效果，获得更好的传感系统信噪比。
如前所述，本发明的滤光片可以提升传感器系统的性能。
本发明还提供了一种传感器系统，图9为基于本发明的传感器系统的示意图， 其中601为本发明的传感器系统。602为半导体激光器，位于传感器的发射端，其发光波长位于800-1800nm波长范围内，其发射光谱具有中心波长，且中心波长的温度漂移系数大于0.04nm/摄氏度，小于0.4nm/摄氏度。此外，发射端还包含光束整形器件604，用于发射光束的准直、聚焦、或光斑pattern的形成等。半导体激光器602发出的激光，经光束整形器件604后照射到被探测物607上。反射光返回经过镜片组605、和基于本发明的滤光片606，到达探测器603。探测器603在光路中位于本发明的滤光片606之后。在实际应用时，滤光片606在光路中可以在镜片组605之前，也可以在镜片组605之后。作为优选的，滤光片606中心波长的温度漂移系数，和半导体激光器602中心波长的温度漂移系数的差值小于0.05nm/摄氏度，滤光片具有良好的温度补偿效果。
以上所述为本发明的实施例，对于本领域的普通技术人员而言，根据本发明的教导，在不脱离本发明的原理和精神的情况下凡依本发明申请专利范围所做的均等变化、修改、替换和变型，皆应属本发明的涵盖范围。

Claims (8)

  1. 具有温度补偿效应的滤光片，其具有800nm到1800nm波长范围部分重叠的通带，其包括基板以及镀制在基板表面的滤光膜层，其特征在于：所述的滤光膜层包括多个高折射率层和多个低折射率层；制成高折射率层的材料至少包括Si∶H或Ge∶H，其中，由Si∶H材料制成的高射折率层在波长范围为800nm到1800nm的折射率均大于3，由Ge∶H材料制成的高射折率层在波长范围为800nm到1800nm的折射率均大于4；低折射率层在波长范围为800nm到1800nm的折射率均小于3；
    所述滤光片的通带具有中心波长，当工作环境温度范围为-40摄氏度到120摄氏度温度范围部分重叠时，其中心波长的温度漂移系数大于0.04nm/摄氏度且小于0.4nm/摄氏度。
  2. 根据权利要求1所述的具有温度补偿效应的滤光片，其特征在于：所述基板的材料热膨胀系数为正数且不大于30ppm/摄氏度。
  3. 根据权利要求1所述的具有温度补偿效应的滤光片，其特征在于：所述的基板为硅材料、熔融石英、基于SiO 2的玻璃、钢化玻璃、有色玻璃、蓝宝石、聚甲基丙烯酸甲酯或聚碳酸酯制成。
  4. 根据权利要求1所述的具有温度补偿效应的滤光片，其特征在于：所述的低折射率层为TiO 2、Nb 2O 5、Ta 2O 5、SiO 2、MgF 2或Si xN y中的至少一种制成。
  5. 根据权利要求1所述的具有温度补偿效应的滤光片，其特征在于：所述的滤光片为干涉滤光片。
  6. 根据权利要求5所述的具有温度补偿效应的滤光片，其特征在于：所述的干涉滤光片为多腔式带通滤光片且其腔的数目为3个以上。
  7. 一种传感器系统，其特征在于：其包括：
    权利要求1至6之一所述的滤光片，其通带包含光源的中心波长；
    半导体激光器，其发光波长位于800nm～1800nm波长范围内，其发射光谱具有中心波长且中心波长的温度漂移系数大于0.04nm/摄氏度并小于0.4nm/摄氏度；
    探测器，用于接收半导体激光器发出的光，探测器在光路中的位置位于滤光片之后。
  8. 根据权利要求7所述的传感器系统，其特征在于：所述滤光片中心波长的温度漂移系数和所述半导体激光器中心波长的温度漂移系数的差值小于0.05nm/摄氏度。
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114637065A (zh) * 2022-02-18 2022-06-17 湖南麓星光电科技有限公司 一种高损伤阈值红外双激光通道滤光片及其制备方法

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115989438A (zh) * 2020-07-01 2023-04-18 富士胶片株式会社 传感器及带通滤光片
CN113703105A (zh) * 2021-09-01 2021-11-26 索尔思光电（成都）有限公司 调节光发射器件全温发射光功率的方法及滤光片生产方法
CN114046811A (zh) * 2021-12-02 2022-02-15 南京牧镭激光科技有限公司 光学集成化的光纤传感解调模块

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20030039847A1 (en) * 2001-08-24 2003-02-27 General Electric Company Optically coated article and method for its preparation
CN104471449A (zh) * 2012-07-16 2015-03-25 Jds尤尼弗思公司 滤光器和传感器系统
CN108761614A (zh) * 2018-08-06 2018-11-06 信阳舜宇光学有限公司 滤光片及包含该滤光片的红外图像传感系统
CN109239827A (zh) * 2018-11-10 2019-01-18 深圳市都乐精密制造有限公司 用于人脸识别系统的低角度偏移光学薄膜滤光片
CN109298477A (zh) * 2017-07-24 2019-02-01 唯亚威通讯技术有限公司 光学滤波器
CN109655954A (zh) * 2019-03-05 2019-04-19 浙江水晶光电科技股份有限公司 滤光片及其制备方法、指纹识别模组及电子设备

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3243474B2 (ja) * 1993-12-28 2002-01-07 光伸光学工業株式会社 多層膜バンドパスフィルタの製造方法及び波長シフト温度係数値が略ゼロの多層膜バンドパスフィルタ
US7049004B2 (en) * 2001-06-18 2006-05-23 Aegis Semiconductor, Inc. Index tunable thin film interference coatings
CN2511984Y (zh) * 2001-12-29 2002-09-18 中国科学院上海技术物理研究所 长波红外宽带滤光片
US10914961B2 (en) * 2017-02-13 2021-02-09 Viavi Solutions Inc. Optical polarizing filter
CN108873135A (zh) * 2018-08-06 2018-11-23 信阳舜宇光学有限公司 一种近红外窄带滤光片及红外成像系统

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20030039847A1 (en) * 2001-08-24 2003-02-27 General Electric Company Optically coated article and method for its preparation
CN104471449A (zh) * 2012-07-16 2015-03-25 Jds尤尼弗思公司 滤光器和传感器系统
CN109298477A (zh) * 2017-07-24 2019-02-01 唯亚威通讯技术有限公司 光学滤波器
CN108761614A (zh) * 2018-08-06 2018-11-06 信阳舜宇光学有限公司 滤光片及包含该滤光片的红外图像传感系统
CN109239827A (zh) * 2018-11-10 2019-01-18 深圳市都乐精密制造有限公司 用于人脸识别系统的低角度偏移光学薄膜滤光片
CN109655954A (zh) * 2019-03-05 2019-04-19 浙江水晶光电科技股份有限公司 滤光片及其制备方法、指纹识别模组及电子设备

Cited By (2)

* Cited by examiner, † Cited by third party
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CN114637065A (zh) * 2022-02-18 2022-06-17 湖南麓星光电科技有限公司 一种高损伤阈值红外双激光通道滤光片及其制备方法
CN114637065B (zh) * 2022-02-18 2024-02-27 湖南麓星光电科技有限公司 一种高损伤阈值红外双激光通道滤光片及其制备方法

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