JP-2026074519-A - Spectroscopic unit and spectroscopic module

Abstract

[Problem] To provide a spectroscopic unit and spectroscopic module that can perform measurements with high accuracy. [Solution] The spectroscopic unit 110 includes a Fabry-Perot interference filter 10 having a pair of mirrors whose distance from each other is variable, an optical system 50 having a first lens 51 that focuses light from an object M onto the Fabry-Perot interference filter 10, and a photodetector 8 that detects light transmitted through the Fabry-Perot interference filter 10. When the distance D1 from the first lens 51 to the object M is 5 cm, and a circular area on the surface of the object M with a diameter D2 of 1 cm is defined as the field of view A, the optical system 50 is configured to allow light with a divergence angle of 1 degree or less to enter the light transmission area of the Fabry-Perot interference filter 10, while preventing light with a divergence angle greater than 1 degree from entering the light transmission area of the Fabry-Perot interference filter 10 from entering the light transmission area. [Selection Diagram] Figure 9

Inventors

• 大山 泰生
• 柴山 勝己
• 能野 隆文
• 笠原 隆

Assignees

• 浜松ホトニクス株式会社

Dates

Publication Date

20260507

Application Date

20241021

Claims (13)

1. A Fabry-Perot interference filter having a pair of mirrors whose distance from each other is variable, An optical system having a first lens that focuses light from an object onto the Fabry-Perot interference filter, The system comprises a photodetector that detects the light transmitted through the Fabry-Perot interference filter, When the distance from the first lens to the object is 5 cm, and the field of view is defined as a circular area on the surface of the object with a diameter of 1 cm, the optical system is configured such that, of the light incident on the first lens from the field of view, light with a divergence angle greater than 1 degree is not incident on the light transmission area of the Fabry-Perot interference filter, while light with a divergence angle of 1 degree or less is incident on the light transmission area. Spectroscopic unit.
2. The pair of mirror portions face each other in a predetermined direction, When viewed from the predetermined direction, the outer edge of the first lens is larger than the outer edge of the Fabry-Perot interference filter. The spectroscopic unit according to claim 1.
3. The aforementioned photodetector is a single-channel element. The spectroscopic unit according to claim 1 or 2.
4. The pair of mirror portions face each other in a predetermined direction, The optical system has a second lens located between the first lens and the Fabry-Perot interference filter. The second lens is configured such that the angle of light transmitted through the second lens with respect to the predetermined direction is smaller than the angle of light incident on the second lens with respect to the predetermined direction. The spectroscopic unit according to claim 1 or 2.
5. The second lens is formed separately from the first lens. The spectroscopic unit according to claim 4.
6. The second lens is formed integrally with the first lens. The spectroscopic unit according to claim 4.
7. The system further comprises a bandpass filter located between the first lens and the Fabry-Perot interference filter. The spectroscopic unit according to claim 1 or 2.
8. The pair of mirror portions face each other in a predetermined direction, When viewed from the predetermined direction, the width of the first lens is at least twice the width of the light transmission region. The spectroscopic unit according to claim 1 or 2.
9. The pair of mirror portions face each other in a predetermined direction, When viewed from the predetermined direction, the width of the first lens is 10 times or more the width of the light transmission region. The spectroscopic unit according to claim 1 or 2.
10. A spectral unit according to claim 1 or 2, The package comprises the aforementioned spectroscopic unit, The package has a light incident portion into which the light from the object is incident, The first lens is located at the light incident portion, Spectroscopic module.
11. The package has a cylindrical portion, The first lens is positioned inside the cylindrical portion, When viewed from the direction of extension of the cylindrical portion, the light-transmitting region is located inside the cylindrical portion. The spectroscopic module according to claim 10.
12. The package further comprises a main body that houses the Fabry-Perot interference filter, The cylindrical portion is connected to the main body so as to protrude from the main body, The light incident portion is formed at the end of the cylindrical portion that protrudes from the main body portion. The spectroscopic module according to claim 11.
13. The system further comprises multiple light sources that emit light toward the aforementioned object, The aforementioned multiple light sources are positioned along the circumferential direction of the cylindrical portion. The spectroscopic module according to claim 11.

Description

This invention relates to a spectroscopic unit and a spectroscopic module. A spectroscopic module is known that comprises a light source that emits light towards an object, a spectroscopic unit that spectrally analyzes the light from the object, and a photodetector that detects the light spectrally analyzed by the spectroscopic unit (see, for example, Patent Document 1). Such a spectroscopic module allows for, for example, non-destructive measurement of the components of an object. Japanese Patent Publication No. 2021-60249 This is a cross-sectional view of a photodetector applied to a spectroscopic module of one embodiment.Figure 1 is a plan view of the light detection device shown.Figure 1 is a perspective view of the Fabry-Perot interference filter shown.Figure 3 is a cross-sectional view of a Fabry-Perot interference filter along the IV-IV line.This is a perspective view of a spectroscopic module in one embodiment.This is a perspective view of a spectroscopic module in one embodiment.Figure 6 is an enlarged cross-sectional view of the spectral module along the line VII-VII shown.This diagram shows the relative positions of the Fabry-Perot interference filter, the first lens, and the second lens.This is a diagram illustrating the function of the second lens.This figure shows the field of view and the configuration of the optical system.This is a schematic diagram showing the angle of light diffusion from an object.This graph shows the results of measuring an object using a spectroscopic module according to one embodiment.This diagram shows the configuration of the optical system in a modified example.This diagram shows the configuration of the optical system in a modified example.This diagram shows the configuration of the optical system in a modified example.This diagram shows the configuration of the spectroscopic module when applied to transmission measurements.This is a cross-sectional view showing the configuration of a modified photodetector.This is a cross-sectional view showing the configuration of a modified photodetector. Embodiments of the present invention will be described in detail below with reference to the drawings. In each drawing, the same or corresponding parts are denoted by the same reference numerals, and redundant descriptions are omitted. [Photodetector] First, a photodetector 1 applied to a spectroscopic module according to one embodiment will be described. The photodetector 1 is, for example, a MEMS-FPI sensor. As shown in Figure 1, the photodetector 1 comprises a housing 2. The housing 2 is a CAN package having a stem 3 and a cap 4. The cap 4 includes a side wall 5 and a top wall 6. The side wall 5 and the top wall 6 are integrally formed from a metal material. The top wall 6 is integrally formed with the cylindrical side wall 5 so as to cover one opening of the side wall 5. The stem 3 is made of a metal material. The stem 3 is hermetically bonded to the cylindrical side wall 5 so as to cover the other opening of the side wall 5. A wiring board 7 is fixed to the inner surface 3a of the stem 3. The substrate material of the wiring board 7 is, for example, silicon, ceramic, quartz, glass, plastic, etc. A photodetector 8 and a temperature compensation element such as a thermistor (not shown) are mounted on the wiring board 7. The photodetector 8 is, for example, an infrared detector. As an infrared detector, for example, a quantum type sensor using InGaAs, a thermopile, or a bolometer can be used. When detecting light in the ultraviolet, visible, and near-infrared wavelength ranges, for example, a silicon photodiode can be used as the photodetector 8. In this example, the photodetector 1 has one photodetector 8 (photodetector). The photodetector 8 is a single-channel element. A single-channel element is an element that outputs a single electrical signal, regardless of whether it has a single light-receiving region (single photoelectric conversion region) or multiple light-receiving regions (multiple photoelectric conversion regions). In a single-channel element with multiple light-receiving regions, for example, the current values obtained from the multiple light-receiving regions are summed up to produce a single electrical signal. Multiple spacers 9 are fixed to the wiring board 7. The material of each spacer 9 is, for example, silicon, ceramic, quartz, glass, or plastic. A Fabry-Perot interference filter 10 is fixed to the multiple spacers 9. That is, the Fabry-Perot interference filter 10 is supported by the multiple spacers 9. The light-transmitting region 10a of the Fabry-Perot interference filter 10 faces the light-receiving portion of the photodetector 8. The spacers 9 may be formed integrally with the wiring board 7. The Fabry-Perot interference filter 10 may be supported by a single spacer 9. Multiple lead pins 11 are fixed to the stem 3. Each lead pin 11 penetrates the stem 3, with electrical insulation and airtightness ensured by an insulating member 17. Each lead pin