# US 11,906,821 B2 · Spatial light modulator, light modulating device, and method for driving spatial light modulator > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,906,821 B2 - Document ID: US11906821B2 - Status: Granted - Kind: B2 - Application number: 16/977,397 - Filed: 2019-02-07 - Published: 2021-02-18 - Granted: 2024-02-20 - Earliest claimed: 2018-03-09 - Assignees: Hamamatsu Photonics K.K. - Applicants: Hamamatsu Photonics K.K. - Inventors: Hiroto Sakai; Munenori Takumi; Hiroshi Tanaka - Web page: https://patentgrep.com/patent/US11906821B2 ## CPC - G02F 1/01: for the control of the intensity, phase, polarisation or colour (G02F1/29, G02F1/35 take precedence) - G02F 1/0121: {Operation of devices; Circuit arrangements, not otherwise provided for in this subclass} - G02F 1/13306: {Circuit arrangements or driving methods for the control of single liquid crystal cells (G02F1/132, G02F1/133382 take precedence)} - G02F 1/133553: {Reflecting elements (associated to illuminating devices G02F1/133605)} - G02F 1/29: for the control of the position or the direction of light beams, i.e. deflection - G03H 1/2294: {Addressing the hologram to an active spatial light modulator} - G02F 2203/12: spatial light modulator - G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS - G03H: HOLOGRAPHIC PROCESSES OR APPARATUS (holograms, e.g. point holograms, used as ordinary optical elements G02B5/32; producing stereoscopic or other three-dimensional effects G02B30/00; diffraction-grating systems G02B27/44; systems using moiré fringes G02B27/60; optical logic elements G02F3/00; stereo-photography G03B35/00; photosensitive materials or processes for photographic purposes G03C; {stereo-photographic or similar processes G03C9/00}; apparatus for processing exposed photographic materials G03D; analogue computers performing mathematical operations with the aid of optical elements G06E3/00; authentication by radiation, of concealed information carried by holograms or diffraction gratings G06K19/16; holographic storage G11B7/0065, G11C13/04; {stereoscopic or other three dimensional effects in television systems H04N13/00}) ## Abstract An SLM includes a modulation unit and a driving circuit. The modulation unit includes a plurality of pixels, and modulates a phase or an intensity of incident light in each pixel according to an amplitude of a drive signal changing periodically with time. The driving circuit provides the drive signal to the modulation unit. The driving circuit performs control such that a phase of the drive signal V1(t) provided to a first pixel group in the plurality of pixels and a phase of the drive signal V2(t) provided to a second pixel group in the plurality of pixels are mutually inverted. ## Claims ### Claim 1 A spatial light modulator comprising: a modulator including a plurality of pixels, and configured to modulate a phase or an intensity of incident light in each pixel according to an amplitude of a drive signal changing periodically with time; and a driving circuit configured to provide the drive signal to the modulator, wherein the driving circuit is configured to perform control such that a phase of the drive signal provided to a first pixel group in the plurality of pixels and a phase of the drive signal provided to a second pixel group in the plurality of pixels are mutually inverted. ### Claim 2 (depends on 1) The spatial light modulator according to claim 1, wherein the modulator includes a liquid crystal layer. ### Claim 3 (depends on 1) The spatial light modulator according to claim 1, wherein the driving circuit is configured to perform control such that an area of the first pixel group and an area of the second pixel group in an irradiation region of the incident light are equal to each other. ### Claim 4 (depends on 1) The spatial light modulator according to claim 1, wherein the driving circuit is configured to variably control a boundary line between the first pixel group and the second pixel group. ### Claim 5 (depends on 4) A light modulation apparatus comprising: the spatial light modulator according to claim 4; and a photodetector configured to detect an intensity of light after modulation, wherein the driving circuit is configured to determine a position of the boundary line between the first pixel group and the second pixel group based on a periodic variation of the intensity of light provided by the photodetector. ### Claim 6 (depends on 1) A light modulation apparatus comprising: the spatial light modulator according to claim 1; a light source configured to provide the incident light to the modulator; and a focusing optical system configured to focus light after modulation output from the modulator. ### Claim 7 (depends on 6) The light modulation apparatus according to claim 6, further comprising a light guide optical system configured to guide light output from the light source to the modulator, wherein the light guide optical system is configured to vary an incident position of light in the modulator. ### Claim 8 (depends on 7) The light modulation apparatus according to claim 7, further comprising: a photodetector configured to detect an intensity of light after modulation; and a light guide optical system controller configured to control the light guide optical system, wherein the light guide optical system controller is configured to determine the incident position of light in the modulator based on a periodic variation of the intensity of light provided by the photodetector. ### Claim 9 A spatial light modulator driving method of driving a spatial light modulator comprising a modulator including a plurality of pixels, and configured to modulate a phase or an intensity of incident light in each pixel according to an amplitude of a drive signal changing periodically with time, wherein a phase of the drive signal provided to a first pixel group in the plurality of pixels and a phase of the drive signal provided to a second pixel group in the plurality of pixels are mutually inverted. ### Claim 10 (depends on 9) The spatial light modulator driving method according to claim 9, wherein the modulator includes a liquid crystal layer. ### Claim 11 (depends on 9) The spatial light modulator driving method according to claim 9, wherein an area of the first pixel group and an area of the second pixel group are equal to each other. ### Claim 12 (depends on 9) The spatial light modulator driving method according to claim 9, wherein a boundary line between the first pixel group and the second pixel group is variable. ### Claim 13 (depends on 12) The spatial light modulator driving method according to claim 12, wherein an intensity of light after modulation is detected, and a position of the boundary line between the first pixel group and the second pixel group is determined based on a periodic variation of the intensity of light. ### Claim 14 (depends on 9) The spatial light modulator driving method according to claim 9, wherein a light guide optical system configured to guide light to the modulator is provided, and the light guide optical system is configured to vary an incident position of light in the modulator. ### Claim 15 (depends on 14) The spatial light modulator driving method according to claim 14, wherein an intensity of light after modulation is detected, and the incident position of light in the modulator is determined based on a periodic variation of the intensity of light.