Spectroscopic detector
By designing the maze structure in the spectrophotometer detector of the micro Raman device, using the difference in inner and outer diameters of the through holes and the movement of the lens barrel, the stray light problem in the detector is solved, significantly improving the signal-to-noise ratio and improving the detection results.
Patent Information
- Application Number
- CN202210963123.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Priority Date
- 2021-08-31
- Filing Date
- 2022-08-11
- Publication Date
- 2024-12-20
- Estimated Expiration
- 2042-08-11
AI Technical Summary
In existing micro Raman devices, there is insufficient countermeasures for detecting stray light in the detector, resulting in poor signal-to-noise ratio.
A spectrophotometer is designed, which ensures that stray light reaches the imaging element by forming a labyrinth structure with multiple reflections between the camera lens and the through hole. It is attenuated multiple times, thereby suppressing the incident of stray light.
The incident of stray light is effectively suppressed, the signal-to-noise ratio of the imaging element is significantly improved, and the detection results are improved.
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Figure CN115728232B_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to spectroscopic detectors. Background Art
[0002] The Raman microscope described in Japanese Patent Application Laid-Open No. 10-90064 has an excitation laser, a spectrometer, and a detector. In the Raman microscope described in Patent Document 1, Raman scattered light is generated from the sample by irradiating the sample with laser light from the excitation laser. The Raman scattered light is dispersed in the spectrometer, and the intensity distribution of the dispersed Raman scattered light is detected in the detector. Summary of the invention
[0003] In the microscopic Raman device described in Japanese Patent Application Laid-Open No. 10-90064, there is no countermeasure for detecting stray light in the detector. The present disclosure is made in view of the above-mentioned problems of the prior art. More specifically, the present disclosure provides a spectroscopic detector capable of suppressing detection of stray light.
[0004] The spectroscopic detector disclosed in the present invention comprises a first housing, a second housing, a camera lens housed in the first housing, and an imaging element housed in the second housing. A first through hole is formed in the first housing. A second through hole is formed in the second housing. The second housing is mounted on the first housing in such a manner that the interior of the second housing is connected to the interior of the first housing by means of the first through hole and the second through hole. When the second housing is mounted on the first housing, the edge of the second through hole is located at a position closer to the inside than the edge of the first through hole. The camera lens has an incident end and an exit end as an end on the opposite side of the incident end in the optical axis direction of the camera lens. The exit end is inserted into the first through hole. The difference between the outer diameter of the camera lens at the exit end and the inner diameter of the first through hole is smaller than the thickness of the first housing at the portion where the first through hole is formed. The imaging element is arranged relative to the exit end with a gap in the optical axis direction of the camera lens.
[0005] In the above-mentioned spectroscopic detector, the camera lens may be divided into a fixed lens barrel located at the incident end side and a movable lens barrel located at the emission end side in the optical axis direction of the camera lens. Alternatively, the movable lens barrel may be movable relative to the fixed lens barrel in the optical axis direction of the camera lens.
[0006] In the above-mentioned spectroscopic detector, the position of the movable lens barrel relative to the fixed lens barrel in the optical axis direction of the camera lens may be moved by rotating the movable lens barrel relative to the fixed lens barrel around the optical axis of the camera lens.
[0007] The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS
[0008] Figure 1 FIG. 1 is a schematic diagram of the structure of the micro-Raman device 100 .
[0009] Figure 2 It is a cross-sectional view of the spectroscopic detector 40 .
[0010] Figure 3 is a side view of the camera lens 43. DETAILED DESCRIPTION
[0011] The details of the embodiments of the present disclosure will be described with reference to the drawings. In the following drawings, the same or corresponding parts are denoted by the same reference numerals, and repeated description will not be repeated.
[0012] (Structure of Micro-Raman Device of Embodiment)
[0013] The structure of the micro-Raman apparatus according to the embodiment will be described below. The micro-Raman apparatus according to the embodiment is referred to as a micro-Raman apparatus 100 .
[0014] The structure of the micro-Raman device 100 will be described below.
[0015] Figure 1 FIG. 1 is a schematic diagram of the structure of the Raman microscope 100. Figure 1 As shown, the Raman microscope device 100 further includes a laser light source 10, a beam splitter 20, an objective lens 30, a spectroscopic detector 40, and a sample placement portion 50. The sample S is stored in the sample placement portion 50.
[0016] The laser light source 10 generates laser light L1. The wavelength of the laser light L1 is a first wavelength. The beam splitter 20 reflects light having a wavelength equal to or less than the first wavelength and transmits light having a wavelength exceeding the first wavelength.
[0017] The laser light L1 generated by the laser light source 10 is reflected by the beam splitter 20. The laser light L1 reflected by the beam splitter 20 is condensed by the objective lens 30 and irradiated onto the sample S.
[0018] By irradiating the sample S with the laser light L1, Raman scattered light L2 is generated from the sample S. The wavelength of the Raman scattered light L2 is shifted from the first wavelength to the long wavelength side. That is, the wavelength of the Raman scattered light L2 is the second wavelength. The Raman scattered light L2 passes through the objective lens 30 and the beam splitter 20 in sequence. The Raman scattered light L2 that has passed through the beam splitter 20 is incident on the spectroscopic detector 40. The structure of the spectroscopic detector 40 will be described later.
[0019] The sample placement section 50 includes a stage 51 and a cover 52. The stage 51 is located inside the sample placement section 50. The sample S is placed on the stage 51. The cover 52 can be opened and closed. By opening the cover 52, operations inside the sample placement section 50 (for example, operations on the sample S) can be performed.
[0020] <Schematic Structure of Spectroscopic Detector 40>
[0021] The spectroscopic detector 40 includes a collimator lens (not shown), a grating 42 , a camera lens 43 , and an imaging element 44 .
[0022] The Raman scattered light L2 incident on the spectroscopic detector 40 is directed toward the collimating lens. The Raman scattered light L2 becomes parallel light by passing through the collimating lens. The Raman scattered light L2 passing through the collimating lens is dispersed by passing through the grating 42. The Raman scattered light L2 dispersed by the grating 42 is focused on the imaging element 44 by the camera lens 43. The spectrum of the Raman scattered light L2 is thus measured.
[0023] <Detailed Structure of Spectroscopic Detector 40>
[0024] Figure 2 is a cross-sectional view of the spectroscopic detector 40. Figure 2 The collimating lens is omitted in the figure. Figure 2 As shown, the spectroscopic detector 40 includes a first housing 45 and a second housing 46 .
[0025] The collimator lens, the grating 42, and the camera lens 43 are housed in the first housing 45. The imaging element 44 is housed in the second housing 46. Although not shown, a cooling device such as a Peltier element for cooling the imaging element 44 and an electronic circuit for controlling the imaging element 44 are also housed in the second housing 46.
[0026] A first through hole 45a is formed in the outer wall portion of the first housing 45. A second through hole 46a is formed in the outer wall portion of the second housing 46. The second housing 46 is mounted on the first housing 45. More specifically, the outer wall portion of the second housing 46 in which the second through hole 46a is formed (hereinafter referred to as the outer wall portion 46b) is mounted on the outer wall portion of the first housing 45 in which the first through hole 45a is formed (hereinafter referred to as the outer wall portion 45b).
[0027] The first through hole 45a connects the inside of the first housing 45 with the outside of the first housing 45. The second through hole 46a connects the inside of the second housing 46 with the outside of the second housing 46. When the second housing 46 is mounted on the first housing 45, the inside of the second housing 46 communicates with the inside of the first housing 45 via the first through hole 45a and the second through hole 46a.
[0028] When the second housing 46 is mounted on the first housing 45, the edge of the second through hole 46a is located inside the edge of the first through hole 45a when viewed from the direction along the optical axis of the camera lens 43. That is, the inner diameter of the second through hole 46a is smaller than the inner diameter of the first through hole 45a.
[0029] The camera lens 43 has an incident end 43a and an exit end 43b. The two ends of the camera lens 43 in the optical axis direction of the camera lens 43 are the incident end 43a and the exit end 43b. The Raman scattered light L2 that has passed through the grating 42 is incident on the camera lens 43 from the incident end 43a. The exit end 43b is the end on the opposite side of the incident end 43a. The exit end 43b is inserted into the first through hole 45a.
[0030] The thickness of the outer wall portion 45b is defined as thickness W. The difference between the inner diameter of the first through hole 45a and the outer diameter of the camera lens 43 at the emission end 43b (the value obtained by subtracting the outer diameter of the camera lens 43 at the emission end 43b from the inner diameter of the first through hole 45a) is smaller than thickness W.
[0031] The camera lens 43 is divided into a fixed lens barrel 431 and a movable lens barrel 432 in the optical axis direction of the camera lens 43. A plurality of lenses (not shown) are stored in the fixed lens barrel 431, and a plurality of lenses (not shown) are stored in the movable lens barrel 432. The movable lens barrel 432 is inserted into the first through hole 45a. The fixed lens barrel 431 is located closer to the incident end 43a side than the movable lens barrel 432.
[0032] The fixed lens barrel 431 is fixed to the inner wall portion 45c located inside the first housing 45. Therefore, the position of the fixed lens barrel 431 in the optical axis direction of the camera lens 43 is fixed. On the other hand, the position of the movable lens barrel 432 relative to the fixed lens barrel 431 in the optical axis direction of the camera lens 43 is movable. By moving the movable lens barrel 432 relative to the fixed lens barrel 431 in the optical axis direction of the camera lens 43, the focus of the imaging element 44 is adjusted.
[0033] Figure 3 is a side view of the camera lens 43. Figure 3 As shown, an external thread 431a is formed on the outer circumferential surface of the fixed lens barrel 431. Although not shown, an internal thread that is threadedly engaged with the external thread 431a is formed on the inner circumferential surface of the movable lens barrel 432. Therefore, by rotating the movable lens barrel 432 around the optical axis of the camera lens 43, the position of the movable lens barrel 432 relative to the fixed lens barrel 431 is moved.
[0034] In addition, a locking ring 433 is threadedly coupled to the external thread 431a. The locking ring 433 is located at a position closer to the incident end 43a side than the movable lens barrel 432. After the movable lens barrel 432 is moved to a desired position, the locking ring 433 rotates around the optical axis of the camera lens 43 until it contacts the movable lens barrel 432. Thus, a locking force is generated between the locking ring 433 and the movable lens barrel 432, thereby limiting the rotation of the movable lens barrel 432. In this way, the locking ring 433 fixes the movable lens barrel 432 at a desired position.
[0035] The image pickup element 44 is, for example, a CCD (Charge Coupled Device) camera. However, the image pickup element 44 is not limited thereto. The image pickup element 44 may also be a CMOS (Complementary Metal Oxide Semiconductor) camera. The image pickup element 44 is arranged relative to the emission end 43b at a distance in the optical axis direction of the camera lens 43. This prevents the emission end 43b from contacting the image pickup element 44 when the movable lens barrel 432 is moved relative to the fixed lens barrel 431 in the optical axis direction of the camera lens 43.
[0036] (Effects of the Micro-Raman Apparatus of the Embodiment)
[0037] The effects of the micro-Raman apparatus 100 will be described below.
[0038] In the spectroscopic detector 40, the movable lens barrel 432 is moved relative to the fixed lens barrel 431 to adjust the focus of the imaging element 44. Therefore, in order to prevent the imaging element 44 from contacting the camera lens 43, it is necessary to ensure the distance between the emission end 43b and the imaging element 44. When the distance between the emission end 43b and the imaging element 44 increases, stray light is more likely to enter the imaging element 44.
[0039] However, in the spectroscopic detector 40, the difference between the inner diameter of the first through hole 45a and the outer diameter of the camera lens 43 at the emission end 43b is smaller than the thickness W. Therefore, in order to pass through the gap between the camera lens 43 and the first through hole 45a, the stray light is reflected multiple times in the gap. Accompanying the multiple reflections, the stray light is attenuated.
[0040] In addition, in the spectroscopic detector 40, the edge of the second through hole 46a is located on the inner side than the edge of the first through hole 45a. Therefore, even if the stray light passes through the gap between the camera lens 43 and the first through hole 45a, it is further repeatedly reflected between the emission end 43b and the outer wall portion 46b in order to reach the inside of the second housing 46. Therefore, the stray light is further attenuated.
[0041] Thus, the spectroscopic detector 40 has a maze structure that attenuates stray light before reaching the imaging element 44, and thus the micro-Raman device 100 having the spectroscopic detector 40 is used to suppress the detection of stray light in the imaging element 44. In addition, suppressing the detection of stray light in the imaging element 44 results in an improvement in the signal-to-noise ratio (S / N ratio) of the imaging element 44.
[0042] Although the embodiments of the present invention have been described, the embodiments disclosed this time should be considered to be illustrative in all aspects and not restrictive. The scope of the present invention is indicated by the claims, and it is intended to include all modifications within the meaning and scope equivalent to the claims.
Claims
1. A spectroscopic detector, wherein: The spectroscopic detector has: The first shell; The second shell; a camera lens housed in the first housing; and an imaging element housed in the second housing, A first through hole is formed in the first housing. A second through hole is formed in the second housing. The second housing is mounted on the first housing in such a manner that the interior of the second housing communicates with the interior of the first housing via the first through hole and the second through hole. When the second housing is mounted on the first housing, the edge of the second through hole is located inside the edge of the first through hole. The camera lens has an incident end and an exit end which is an end on the opposite side of the incident end in the optical axis direction of the camera lens. The emission end is inserted into the first through hole, The difference between the outer diameter of the camera lens at the emission end and the inner diameter of the first through hole is smaller than the thickness of the first housing at a portion where the first through hole is formed. The imaging element is disposed opposite to the emission end with a gap therebetween in the optical axis direction of the camera lens.
2. The spectroscopic detector according to claim 1, wherein: The camera lens is divided into a movable lens barrel inserted into the first through hole and a fixed lens barrel located closer to the incident end than the movable lens barrel in the optical axis direction of the camera lens. The movable lens barrel is movable relative to the fixed lens barrel in an optical axis direction of the camera lens.
3. The spectroscopic detector according to claim 2, wherein: The position of the movable lens barrel relative to the fixed lens barrel in the optical axis direction of the camera lens can be moved by rotating the movable lens barrel relative to the fixed lens barrel about the optical axis of the camera lens.