Spectral sensor

• US 9,846,076 B2
• Filed: 05/08/2013
• Issued: 12/19/2017
• Est. Priority Date: 05/18/2012
• Status: Active Grant

• Current Assignee: Hamamatsu Photonics KK
• Original Assignee: Hamamatsu Photonics KK
• Inventors: Shibayama, Katsumi, Kasahara, Takashi
• Primary Examiner(s): Chowdhury, Tarifur
• Assistant Examiner(s): Amara, Mohamed K
• Application Number:
  US14/400,695
• Publication Number:
  US 20150153224A1
• Time in Patent Office: 1,686 Days
• CPC Class Codes: G01J 3/0259 Monolithic
• CPC Class Codes: G01J 3/0262 Constructional arrangements for removing stray light
• CPC Class Codes: G01J 3/0289 Field-of-view determination; Aiming or pointing of a spectrometer; Adjusting alignment; Encoding angular position; Size of measurement area; Position tracking
• CPC Class Codes: G01J 3/26 using multiple reflection, e.g. Fabry-Perot interferometer, variable interference filters
• CPC Class Codes: G01J 3/36 Investigating two or more bands of a spectrum by separate detectors
• CPC Class Codes: G01J 3/51 using colour filters

Abstract

A spectroscopic sensor comprises an interference filter unit, a light detection substrate, and a separator. The interference filter unit has a cavity layer and first and second mirror layers opposing each other through the cavity layer and selectively transmits therethrough a predetermined wavelength range of light according to its incident position from the first mirror layer side to the second mirror layer side. The light detection substrate has a light-receiving surface for receiving light transmitted through the interference filter unit and detects the light incident on the light-receiving surface. The separator extends from the cavity layer to at least one of the first and second mirror layers and optically separates the interference filter unit as seen in a predetermined direction intersecting the light-receiving surface.

Claims

1. A spectroscopic sensor comprising:

an interference filter unit, having a cavity layer and first and second mirror layers opposing each other through the cavity layer, for selectively transmitting therethrough a predetermined wavelength range of light according to an incident position thereof from the first mirror layer side to the second mirror layer side;

a light detection substrate, having a light-receiving surface for receiving the light transmitted through the interference filter unit, for detecting the light incident on the light-receiving surface;

a separator, extending from the cavity layer to at least one of the first and second mirror layers, for optically separating the interference filter unit as seen in a predetermined direction intersecting the light-receiving surface;

the interference filter unit has a first region in which the distance between the first and second mirror layers varies, and a second region surrounding the perimeter of the first region as seen in the predetermined direction; and

the cavity layer is formed continuously over the first and second regions and the cavity layer is a solid body.

2. A spectroscopic sensor according to claim 1, wherein the separator extends from the cavity layer to at least the second mirror layer.

3. A spectroscopic sensor according to claim 2, wherein the separator extends from the cavity layer to both of the first and second mirror layers.

4. A spectroscopic sensor according to claim 1, further comprising a first coupling layer, arranged between the interference filter unit and the light detection substrate, for transmitting therethrough light advancing from the interference filter unit to the light detection substrate;

wherein the separator reaches the first coupling layer through the second mirror layer.

5. A spectroscopic sensor according to claim 1, further comprising:

a light-transmitting substrate for transmitting therethrough the light incident on the interference filter unit; and

a second coupling layer, arranged between the light-transmitting substrate and the interference filter unit, for transmitting therethrough the light advancing from the light-transmitting substrate to the interference filter unit;

wherein the separator reaches the second coupling layer through the first mirror layer.

6. A spectroscopic sensor according to claim 5, wherein the cavity layer and second coupling layer are made of the same material.

7. A spectroscopic sensor according to claim 1, wherein the distance in the predetermined direction between the first and second mirror layers varies;

wherein the distance in the predetermined direction between an end part on the light-receiving surface side of the separator and the light-receiving surface is fixed; and

wherein the distance in the predetermined direction between an end part of the separator on the side opposite from the light-receiving surface and the light-receiving surface is fixed.

8. A spectroscopic sensor according to claim 1, wherein the separator exists such as to traverse the light-receiving surface as seen in the predetermined direction.

9. A spectroscopic sensor according to claim 1, further comprising an antireflection film, arranged between the interference filter unit and the light detection substrate, for preventing the light incident on the light-receiving surface from being reflected.

10. A spectroscopic sensor according to claim 1, wherein the surface on the interference filter unit side of the light detection substrate is provided with antireflection processing for preventing the light incident on the light-receiving surface from being reflected.

11. A spectroscopic sensor according to claim 1, wherein the predetermined direction is a direction perpendicular to the light-receiving surface.