# US 2015/0146210 A1 · Wavelength tunable light source > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2015/0146210 A1 - Document ID: US20150146210A1 - Status: Published application - Kind: A1 - Application number: 14/528,791 - Filed: 2014-10-30 - Published: 2015-05-28 - Earliest claimed: 2013-11-23 - Assignees: Canon Kabushiki Kaisha - Applicants: Canon Kabushiki Kaisha - Inventors: Koichiro Nakanishi - Web page: https://patentgrep.com/patent/US20150146210A1 ## CPC - G01B 9/02091: Tomographic interferometers, e.g. based on optical coherence - G01B 9/02004: using frequency scans - G01B 9/02069: {Synchronization of light source or manipulator and detector} - H01S 5/14: External cavity lasers (H01S5/18 takes precedence; mode locking H01S5/065) - H01S 5/18366: {Membrane DBR, i.e. a movable DBR on top of the VCSEL} - H01S 3/1053: {Control by pressure or deformation} - G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS - H01S: DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL ## Abstract To provide a wavelength tunable light source which can both ensure operation speed and reduce a drive voltage. A wavelength tunable light source according to the present invention includes a pair of reflectors at least one of which is a movable reflector, an active layer provided between the pair of reflectors, and a beam on part of which the movable reflector is formed and which is supported by a support member. The beam includes a blade part projecting between the support member and the movable reflector in a direction intersecting a stretching direction of the beam, and a center of gravity of the beam in the stretching direction is located at a distance less than half a length of the beam in the stretching direction. ## Claims ### Claim 1 A wavelength tunable light source comprising: a pair of reflectors at least one of which is a movable reflector; an active layer provided between the pair of reflectors; and a beam on part of which the movable reflector is formed and which is supported by a support member, wherein the beam includes a blade part projecting between the support member and the movable reflector in a direction intersecting a stretching direction of the beam, and a center of gravity of the beam in the stretching direction is located at a distance less than half a length of the beam from the support member in the stretching direction. ### Claim 2 (depends on 1) The wavelength tunable light source according to claim 1, wherein the center of gravity of the beam in the stretching direction is located at a distance between 25% and 40% of the length of the beam from the support member in the stretching direction, both inclusive. ### Claim 3 (depends on 1) The wavelength tunable light source according to claim 1, wherein the blade part is spaced away from the support member. ### Claim 4 (depends on 1) The wavelength tunable light source according to claim 1, further comprising a fixed electrode placed facing the beam, wherein: at least the blade part is a movable electrode; and the fixed electrode and the movable electrode are configured such that an electrostatic force is applied between the fixed electrode and the movable electrode. ### Claim 5 (depends on 4) The wavelength tunable light source according to claim 4, wherein the blade part and the beam are movable electrode. ### Claim 6 (depends on 1) The wavelength tunable light source according to claim 1, wherein the blade part is made of a same material as the beam and formed unitary with the beam. ### Claim 7 (depends on 1) The wavelength tunable light source according to claim 1, wherein the blade part and the beam are separate members. ### Claim 8 (depends on 1) The wavelength tunable light source according to claim 1, wherein the blade part is located at a distance less than half the length of the beam from the support member in the stretching direction. ### Claim 9 (depends on 1) The wavelength tunable light source according to claim 1, wherein a connecting portion between the beam and the blade part is shorter in length than the blade part in the stretching direction of the beam. ### Claim 10 (depends on 1) The wavelength tunable light source according to claim 1, wherein a center-of-gravity position of a connecting portion in the stretching direction of the beam is not matched with a center-of-gravity position of the blade part in the stretching direction of the beam. ### Claim 11 (depends on 1) The wavelength tunable light source according to claim 1, wherein the active layer includes a semiconductor. ### Claim 12 (depends on 1) The wavelength tunable light source according to claim 1, wherein at least one of the pair of reflectors includes a distributed Bragg reflector. ### Claim 13 (depends on 1) The wavelength tunable light source according to claim 1, wherein at least one of the pair of reflectors includes a high contrast grating. ### Claim 14 (depends on 1) An optical coherence tomography apparatus comprising: the wavelength tunable light source according to claim 1; a specimen measuring unit adapted to illuminate a specimen with light from the wavelength tunable light source and transmit reflected light from the specimen, a reference unit adapted to direct the light from the wavelength tunable light source at a reference mirror and transmit light from the reference mirror, an interference unit adapted to make the two lights interfere with each other; a light detector unit adapted to detect interference light obtained by the interference unit; and an image processing unit adapted to perform image processing based on the interference light detected by the light detector unit.