# US 2013/0155488 A1 · System Producing True Colors Using a Digital Micromirror Device Projector and Method for Controlling Same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2013/0155488 A1 - Document ID: US20130155488A1 - Status: Published application - Kind: A1 - Application number: 13/325,900 - Filed: 2011-12-14 - Published: 2013-06-20 - Earliest claimed: 2011-12-14 - Assignees: Columbia Insurance Company - Inventors: Patrick Tak Fu Chong; Hugh Fairman - Web page: https://patentgrep.com/patent/US20130155488A1 ## CPC - G02B 26/0841: {the reflecting element being moved or deformed by electrostatic means} - G01J 3/021: {using plane or convex mirrors, parallel phase plates, or particular reflectors} - G01J 3/0229: {using masks, aperture plates, spatial light modulators or spatial filters, e.g. reflective filters} - G01J 3/463: {Colour matching} - G01J 3/506: {measuring the colour produced by screens, monitors, displays or CRTs} - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - G01J: MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY (light sources F21, H01J, H01K, H05B; investigating properties of materials by optical means G01N) ## Abstract The present invention is directed to a method of utilizing a digital micromirror device (DMD) to spectrally matching a standard or device-independent color. DMD can be fitted on an integrated chip and can provide more than one thousand (1,000) color primary channels for low metameric color matching producing a spectrally matched batch color. This represents a two orders of magnitude improvement in color matching. ## Claims ### Claim 1 A method for spectrally matching a standard color, wherein the standard color is device-independent, comprising the steps of a. obtaining a spectral power distribution (SPD) curve of the standard color; b. providing a digital micromirror device (DMD) having “n” rows and “m” columns of micromirrors; c. projecting a substantially full visible spectrum of electromagnetic radiation on to the DMD; and d. modulating said substantially full visible spectrum of electromagnetic radiation to create a modulated visible electromagnetic radiation with the DMD, wherein said modulated radiation spectrally matches the SPD of the standard color. ### Claim 2 (depends on 1) The method of claim 1, wherein contiguous groups of micromirrors form primary color channels for the modulated visible electromagnetic radiation. ### Claim 3 (depends on 2) The method of claim 2, wherein the contiguous groups comprise columns of micromirrors. ### Claim 4 (depends on 3) The method of claim 3, wherein a single column is a single primary color channel. ### Claim 5 (depends on 1) The method of claim 1, wherein in step (a) a spectroradiometer obtains the SPD curve and the SPD curve comprises a “k” number of spectral points, and wherein the “m” columns form the primary color channels for color matching. ### Claim 6 (depends on 5) The method of claim 5, wherein “k” is substantially similar to “m”. ### Claim 7 (depends on 1) The method of claim 1, further comprising the steps of identifying two adjacent mirror row radiance for each column where the measured radiance of the standard falls between. ### Claim 8 (depends on 7) The method of claim 7, further comprising the step of interpolating to identify the row number of the DMD with similar radiance at said column. ### Claim 9 (depends on 5) The method of claim 5, wherein “k” is different than “m”. ### Claim 10 (depends on 1) The method of claim 1, further including a step of conducting a first bandpass correction to the SPD curve from step (a) to a putative bandwidth. ### Claim 11 (depends on 10) The method of claim 10, further including a step of conducting a second bandpass correction to the modulated visible electromagnetic radiation from step (d) to said putative bandwidth. ### Claim 12 (depends on 11) The method of claim 11, wherein the first or second bandpass correction comprises correcting according to ASTM E2729. ### Claim 13 (depends on 11) The method of claim 11, wherein the first or second bandpass correction comprises correcting a first and a last interval of columns and then correcting the interior intervals of columns. ### Claim 14 (depends on 11) The method of claim 11, wherein the first or second bandpass correction comprises a simplified ASTM E2729 comprising a single equation correction. ### Claim 15 (depends on 4) The method of claim 4, further comprising a step of obtaining a wavelength for each column. ### Claim 16 (depends on 15) The method of claim 15, further comprising the step of interpolating using cubic Lagrange interpolating to obtain the wavelength for each of the “m” columns of the DMD. ### Claim 17 (depends on 15) The method of claim 15, wherein the step of obtaining the wavelength including the steps of measuring the wavelengths with a spectroradiometer and interpolating the measured wavelengths. ### Claim 18 (depends on 15) The method of claim 15, further comprising a step of determining a cumulative radiance value for each column. ### Claim 19 (depends on 15) The method of claim 15, further comprising a step of determining a wavelength shift as a function of the cumulative radiance values. ### Claim 20 (depends on 11) The method of claim 11, wherein the putative bandwidth of the corrected modulated visible electromagnetic radiation is matched to putative bandwidth of the corrected SPD curve. ### Claim 21 (depends on 1) The method of claim 1, wherein step (d) further comprising the step of instructing the DMD to open a number of rows of micromirrors for any column of micromirrors. ### Claim 22 (depends on 1) The method of claim 1, wherein step (d) further comprising the step of binary pulse width modulating. ### Claim 23 (depends on 2) The method of claim 2, wherein the contiguous groups comprises rows of micromirrors forming the primary color channels. ### Claim 24 (depends on 1) The method of claim 1, further comprising a step for minimizing color metamerism or color inconstancy. ### Claim 25 (depends on 24) The method of claim 24 comprising a step of multiplying the measured spectral reflected radiance factors of the standard color by a SPD of a known illuminant or source.