SYSTEM AND METHOD FOR CONTROLLING AN OPTICAL FILTER ASSEMBLY

• Main Authors: GIESBRECHT, Corbin Abe, BREMNER, Glen Ramsay, FINDEN, Jeremy Graham, SMIT, Matthew Paul, BRANDA, Neil Robin, LAM, Duhane, PILAPIL, Matt Andrew
• Format: Patent
• Language: English; French; German
• Published: 10.01.2018
• Subjects: DEVICES OR ARRANGEMENTS, THE OPTICAL OPERATION OF WHICH ISMODIFIED BY CHANGING THE OPTICAL PROPERTIES OF THE MEDIUM OF THEDEVICES OR ARRANGEMENTS FOR THE CONTROL OF THE INTENSITY,COLOUR, PHASE, POLARISATION OR DIRECTION OF LIGHT, e.g.SWITCHING, GATING, MODULATING OR DEMODULATING; DOORS, WINDOWS, SHUTTERS, OR ROLLER BLINDS IN GENERAL; FIXED CONSTRUCTIONS; FIXED OR MOVABLE CLOSURES FOR OPENINGS IN BUILDINGS, VEHICLES,FENCES OR LIKE ENCLOSURES IN GENERAL, e.g. DOORS, WINDOWS,BLINDS, GATES; FREQUENCY-CHANGING; LADDERS; NON-LINEAR OPTICS; OPTICAL ANALOGUE/DIGITAL CONVERTERS; OPTICAL LOGIC ELEMENTS; OPTICS; PHYSICS; TECHNIQUES OR PROCEDURES FOR THE OPERATION THEREOF

An optical filter and control system (40) suitable for a dimmable room window comprises a hybrid photochromic-electrochromic optical filter assembly (46) whose transmittance is variable, a controller (48) coupled to it which controls its transmittance (32) and a memory unit (49) coupled to the controller (48) which stores the statements and instructions to be executed by the controller (48) in order to switch the optical filter assembly (46) between operating states. The controller (48) is adapted to maintain the optical filter assembly (46) in a "hold mode" by supplying a pulse-width-modulated (PWM) voltage signal across it so that its transmittance (32) is held both at a certain average value (which can correspond to an intermediate operating state between the fully dark and fully light states) and at a certain variance; the average value of the transmittance (32) being held between lower (33) and upper (34) transmittance thresholds.