A manual drive assembly for a manually-operated window treatment based on a drive chain formed as a loop, may incorporate one or more intermediate tensioners disposed between two ends of the loop. The loop may be formed between a manual clutch mechanism coupled to the window treatment and an end tensioner. The one or more intermediate tensioners may serve to limit slack in the loop such that sides of the loop cannot be pulled to create a large loop, for example, having a gap of four inches or greater, between the hanging sides of the cord.

A window shade includes a reel and a roller pivotally connected with a head frame at two spaced-apart positions, a clutch operatively connected with the roller and switchable between an engaged state preventing the roller from rotating in a first direction and a disengaged state for rotation of the roller in an opposite second direction, and a panel assembly including multiple transversal vanes respectively connected with a first and a second panel. The reel is rotatable to wind and unwind the panel assembly with the first panel remaining in contact with the roller. The panel assembly is switchable between an open state for light passage and a closed state blocking light passage by rotating the transversal vanes. The reel is rotatable in an unwinding direction while the roller is kept stationary by the clutch in the engaged state for switching the panel assembly from the closed to open state.

A window shade includes a reel and a roller pivotally connected with a head frame at two spaced-apart positions, a clutch operatively connected with the roller and switchable between an engaged state preventing the roller from rotating in a first direction and a disengaged state for rotation of the roller in an opposite second direction, and a panel assembly including multiple transversal vanes respectively connected with a first and a second panel. The reel is rotatable to wind and unwind the panel assembly with the first panel remaining in contact with the roller. The panel assembly is switchable between an open state for light passage and a closed state blocking light passage by rotating the transversal vanes. The reel is rotatable in an unwinding direction while the roller is kept stationary by the clutch in the engaged state for switching the panel assembly from the closed to open state.

A window covering includes a positional adjustment mechanism connected to a first rail that includes a spring motor unit, a first lift cord pulley connected to the spring motor unit, a first lift cord collection mechanism having a first roller positioned in the first rail, and a first lift cord that extends from the first lift cord pulley through window covering material such that a portion of the first lift cord passes along the first roller. The first roller is configured so that it only rotates a pre-selected number of revolutions when the window covering material is moved from the extended position to the retracted such that the first roller no longer rotates in the second rotational direction as the window covering material is moved from an extended position to a retracted position after having rotated the pre-selected number of revolutions in the second rotational direction.

An integrated-optics MEMS-actuated beam-steering system is disclosed, wherein the beam-steering system includes a lens and a programmable vertical coupler array having a switching network and an array of vertical couplers, where the switching network can energize of the vertical couplers such that it efficiently emits the light into free-space. The lens collimates the light received from the energized vertical coupler and directs the output beam along a propagation direction determined by the position of the energized vertical coupler within the vertical-coupler array. In some embodiments, the vertical coupler is configured to correct an aberration of the lens. In some embodiments, more than one vertical coupler can be energized to enable steering of multiple output beams. In some embodiments, the switching network is non-blocking.

An integrated-optics MEMS-actuated beam-steering system is disclosed, wherein the beam-steering system includes a lens and a programmable vertical coupler array having a switching network and an array of vertical couplers, where the switching network can energize of the vertical couplers such that it efficiently emits the light into free-space. The lens collimates the light received from the energized vertical coupler and directs the output beam along a propagation direction determined by the position of the energized vertical coupler within the vertical-coupler array. In some embodiments, the vertical coupler is configured to correct an aberration of the lens. In some embodiments, more than one vertical coupler can be energized to enable steering of multiple output beams. In some embodiments, the switching network is non-blocking.

A Venetian blind includes a plurality of slats arranged between a headrail and a bottom rail. Two rotary drums are disposed in two brackets mounted in the headrail and connected with each other through a transmission shaft. A first drawing member is connected with one rotary drum, and a second drawing member is connected with the other rotary drum. When the first drawing member is pulled downward, the rotary drums are rotated from a first position to a second position, such that the ladder cords are driven by the rotation of the rotary drums to tilt the slats to a closed position. When the second drawing member is pulled downward, the rotary drums are rotated from the second position to the first position, such that the ladder cords are driven by the rotation of the rotary drums to tilt the slats to an open position.

A Venetian blind includes a plurality of slats arranged between a headrail and a bottom rail. Two rotary drums are disposed in two brackets mounted in the headrail and connected with each other through a transmission shaft. A first drawing member is connected with one rotary drum, and a second drawing member is connected with the other rotary drum. When the first drawing member is pulled downward, the rotary drums are rotated from a first position to a second position, such that the ladder cords are driven by the rotation of the rotary drums to tilt the slats to a closed position. When the second drawing member is pulled downward, the rotary drums are rotated from the second position to the first position, such that the ladder cords are driven by the rotation of the rotary drums to tilt the slats to an open position.

An elastic cord device for use in combination with a window covering device of the type comprising a pulley, a plurality of lift cords, a head rail, the lift cords used to raise and lower a window covering material. The elastic cord device can have a spiral helical shape. The elastic cord device is exposed and accessible so that the elastic cord device can be pulled to raise and lower the window covering material. A window covering device comprising an elastic cord device, a head rail, a pulley, window covering material and lift cords; the elastic cord device is used to operate the window covering.

An elastic cord device for use in combination with a window covering device of the type comprising a pulley, a plurality of lift cords, a head rail, the lift cords used to raise and lower a window covering material. The elastic cord device can have a spiral helical shape. The elastic cord device is exposed and accessible so that the elastic cord device can be pulled to raise and lower the window covering material. A window covering device comprising an elastic cord device, a head rail, a pulley, window covering material and lift cords; the elastic cord device is used to operate the window covering.