Spectrometer and incident light limiting member to be used for the same

• US 10,641,656 B1
• Filed: 12/20/2018
• Issued: 05/05/2020
• Est. Priority Date: 12/20/2018
• Status: Active Grant

• Current Assignee: Shimadzu Corporation
• Original Assignee: Shimadzu Corporation
• Inventors: Kobayashi, Tomoari
• Primary Examiner(s): Chowdhury, Tarifur R
• Assistant Examiner(s): Cook, Jonathon
• Application Number:
  US16/226,860
• Time in Patent Office: 502 Days
• Field of Search: 356328
• CPC Class Codes: G01J 3/0229 using masks, aperture plates, spatial light modulators or spatial filters, e.g. reflective filters
• CPC Class Codes: G01J 3/024 using means for illuminating a slit efficiently (e.g. entrance slit of a spectrometer or entrance face of fiber)
• CPC Class Codes: G01J 3/0262 Constructional arrangements for removing stray light
• CPC Class Codes: G01J 3/04 Slit arrangements slit adjustment
• CPC Class Codes: G01J 3/18 using diffraction elements, e.g. grating gratings per se G02B

Abstract

Provided are a spectrometer capable of more effectively reducing stray light and an incident light limiting member to be used for the spectrometer. At least a part of light not entering an effective area of a diffraction grating is blocked by being reflected by a mask plate provided between an incidence plate and the diffraction grating. Further, the light reflected by the mask plate is attenuated in a trap space. Thus, the light blocked by the mask plate does not reach the diffraction grating side and does not function as a stray light source, so that stray light can be more effectively reduced.

Claims

1. A spectrometer comprising:

an incidence slit through which light from a light source passes is formed;

a diffraction grating that disperses the light having passed through the incidence slit by refracting, in an effective area of the diffraction grating;

a mask that is provided between the incidence slit and the diffraction grating and blocks, by reflection, at least a part of the light having passed through the incidence slit but not entering the effective area; and

a body including a trap space that attenuates the light reflected by the mask part, the body being provided between the incidence slit and the mask.

2. The spectrometer according to claim 1, wherein

the diffraction grating is rotatably held around a rotation axis,

the mask blocks, by reflection, light not entering the effective area in a state in which the diffraction grating is rotated at a rotational position at which an amount of light entering at least the effective area is largest.

3. The spectrometer according to claim 1, wherein the mask is detachably attached to the body.

4. The spectrometer according to claim 1, wherein the mask and the trap are integrally formed.

5. The spectrometer according to claim 1, wherein a low-reflectance member that reflects light while attenuating the light is provided on the mask.

6. The spectrometer according to claim 1, wherein a low-reflectance member that reflects light while attenuating the light is provided on an inner surface of the trap space.

7. An incident light limiting member that limits light from a light source entering a spectrometer having a diffraction grating, the incident light limiting member comprising:

an incidence slit through which light from the light source passes is formed;

a mask that is provided between the incidence slit and the diffraction grating and blocks, by reflection, a part of light having passed through the incidence slit but not entering the effective area; and

a body including a trap space that attenuates the light reflected by the mask, the body being provided between the incidence slit and the mask.