A synchronous DC-DC converter having a soft-stop function includes an output stage for supplying an output voltage, wherein the output stage includes a high-side transistor for charging the output voltage and a low-side transistor for discharging the output voltage; an output control circuit, coupled to the output stage, for controlling the high-side transistor and the low-side transistor of the output stage; at least one protection device, for controlling the high-side transistor to be turned off when a specific situation occurs, in order to stop supplying the output voltage; and a soft-stop control circuit, coupled to the output control circuit, for controlling the low-side transistor of the output stage to be turned on when the protection device controls the high-side transistor to be turned off or the synchronous DC-DC converter is disabled, in order to discharge the output voltage.

A step-down regulator comprising a pseudo constant on time control circuit is disclosed, comprising an on-time generator configured to receive a switching signal provided by the step-down regulator and a control signal provided by the pseudo constant on time control circuit, and generates an on-time signal; a feedback control circuit configured to receive a feedback signal representative of the output voltage of the step-down regulator and generate an output signal; and a logic control circuit coupled to the on-time generator and the feedback control circuit to receive the on-time signal and the output signal and generating the control signal, and a power stage configured to receive an input voltage and the control signal and generate the switching signal.

Systems and methods that provide control circuits having multiple sub-control inputs that control operation of a power electronics device (e.g., a power converter). Each of the multiple sub-control inputs are output from a separate sub-control circuit that includes a feedback circuit having an input tied to a common control node. The common control node is coupled to an input of a controller (e.g., a PWM controller). Outputs of each of the sub-control circuits are coupled to the common control node by a respective switch (e.g., diode, transistor, etc.) so that each of the sub-control circuits may be selectively coupled to the common control node to provide a control signal to a controller. Since components of each of the feedback compensations circuits are biased at a regulation voltage instead of a higher power supply voltage, the control circuit may switch between control modes with minimal delay.

A bootstrap assist circuit and a startup circuit comprising a voltage controlled switch and a startup ramp voltage generator connected to the voltage controlled switch that will control a high side switch, a dimming interface or an enable/disable input function. Said system is used to provide a bootstrap technique to continuously switch a floating high side switch (MOSFET) by continuously charging a capacitor and then “level shifting” said capacitor voltage across the gate and source of the said high side switch to turn the switch on.

A reference voltage circuit for generating a reference voltage to be referred when a pixel signal is digitally converted, includes ramp voltage generating means for generating a ramp voltage which drops from a predetermined initial voltage at a certain gradient, a transistor for forming, together with the ramp voltage generating means, a current mirror circuit, and gain change means for changing a current value of a current flowing from a predetermined power supply via the transistor to change the gradient of the ramp voltage generated by the ramp voltage generating means.

A current mirror circuit, receiving an input current and outputting a plurality of mirroring currents, comprising: a first transistor, wherein a control terminal and a first terminal of the first transistor are connected to a first mirroring current of the input current; at least one second transistor, wherein a control terminal and a first terminal of the at least one second transistor are connected to the at least one second mirroring current of the input current; and a plurality of third transistors, outputting the plurality of mirroring currents from first terminals of the plurality of third transistors, wherein control terminals of the plurality of third transistors are connected to control terminals of the first transistor and the at least one second transistor. The first transistor, the at least one second transistor and the plurality of third transistors are identical.

A power-supply circuit for a DC appliance includes an input unit including a first terminal and a second terminal so as to receive a DC current, an output unit including a third terminal to output the DC current entered by the input unit and a fourth terminal, a connection unit including a first conductive line and a second conductive line so as to interconnect the input unit and the output unit, a rectifier unit including first to fourth diodes coupled as a bridge diode format so as to rectify the input DC current in a predetermined direction, an inductor unit that is connected in series to the rectifier unit in such a manner that the input DC current is gradually increased from an abrupt change time point of the DC current, and a condenser unit that is connected in series to the inductor unit.

A method for linearizing voltage transmission through a transformer including a magnetic core and, input and output windings. A measurement signal is supplied to the input winding at a first frequency and an output signal is measured at the output winding of the transformer, wherein the voltage of the measurement signal may be so low that the transformer operates in a non-linear region. The method includes, for a conditioning signal, selecting a second frequency different from the first frequency, defining an amplitude value of the conditioning signal and supplying the conditioning signal to the input winding at the second frequency with the defined amplitude value so that the transformer operates in its linear region.

In accordance with an embodiment, a circuit includes a first transistor, a second transistor having a reference node coupled to an output node of the first transistor, and a control circuit. The control circuit is configured to couple a second reference node to a control terminal of the second transistor during a first mode of operation, couple a floating reference voltage between the control terminal of the second transistor and the reference terminal of the second transistor during a second mode of operation and during a third mode of operation, and couple a third reference node to the reference terminal of the second transistor during the third mode of operation. The second reference node is configured to have a voltage potential operable to turn-on the second transistor, and the floating reference voltage is operable to turn on the second transistor.

An electronic apparatus includes a switching element which has a control terminal and is driven by controlling voltage of the control terminal, a driving power supply circuit which supplies voltage required for driving the switching element, an on-driving circuit which is connected to the driving power supply circuit and the control terminal of the switching element and is supplied with voltage from the driving power supply circuit, and which applies a constant current to the control terminal of the switching element to charge the control terminal, thereby turning on the switching element, and at least one diode which is connected between the on-driving circuit and the control terminal of the switching element. The on-driving circuit applies a constant current to the control terminal of the switching element through the diode.

Polyphase converter, comprising a plurality of electrical phases (11 to 16), which can each be driven by switching means (21 to 26), wherein at least one coupling means (31 to 39) is provided, which magnetically couples at least one first phase (11) to at least one further phase (12, 14, 16), wherein at least two phases (11, 12) to be coupled are surrounded at least partially by the coupling means (31), wherein at least one insulating body (72) is provided, which on the upper or lower side thereof accommodates the phases (11 to 16) to be coupled and on which at least one fastening means (74, 76, 90) is provided, which interacts with at least one of the phases (11 to 16) for fastening purposes.

An integrated power quality control system includes a transformer with a primary winding, a secondary winding and a compensation winding wound on a magnetic core. A power electronic converter in the system provides a reference voltage to the compensation winding for injecting a series voltage in the secondary winding of the transformer. A controller is utilized to generate a reference control voltage for the power electronic converter based on a power quality control requirement.

A bridge-less step-up switching power supply device includes (i) a first and a second reactor having: a first and a second main winding connected to a first and a second input terminal, respectively; and a first and a second auxiliary winding magnetically coupled to the first main winding and connected to the first and second main windings, the first and second auxiliary windings having a first and a second leakage inductance, respectively; (ii) a first and a second diode connected between the first and second auxiliary windings and a first output terminal, respectively; (iii) a first capacitor connected between the first output terminal and a second output terminal; (iv) a second capacitor connected between a connection point of a third switch and a fourth switch, and the first output terminal; and (v) a controller for controlling turning on/off of first to fourth switches.

A system that manages a supplemental energy source connected to a power grid uses a two stage control strategy to manage power transfers in and out of the power grid as well as in and out of an energy storage system, such as a battery bank. One stage uses a non-linear transfer function to control an output frequency of a DC-to-AC inverter to limit undesired effects of power transients that occur on the grid. A second stage uses control strategy for transferring energy between the energy storage system and an internal DC link based on a relationship between a voltage on a DC link connecting the first and second stages and a DC link reference voltage, the voltage on the DC link, and a voltage at the energy storage system. The control strategy includes rapid charging, over-charging protection, and grid transient stabilization.

A switched mode power supply provides a reduction of switching losses and increased efficiency. The switched mode power supply includes a first switch coupled to an input terminal configured to receive an input voltage, a second switch, an inductor and an output capacitor. The first switch and the second switch are coupled together at a node, the inductor is coupled between the node and an output terminal, and the output capacitor is coupled to the output terminal. The switched mode power supply further includes a transformer coupled between a control input of the first switch and the node and a pulse generator connected to a control input of the second switch. Further, the transformer includes at most two windings, in particular a primary winding and a secondary winding which are not directly connected to each other.

There is provided a DC-DC converter which converts an input voltage into an output voltage for supply to a load, in which an input terminal receives the input voltage, an output terminal outputs the output voltage, power stages each includes: a high side switch, a low side switch and an inductor, the control unit executes a first mode and a second mode wherein the first mode controls the high side switch and the low side switch in each of the power stages so that a ratio of an output current in each of the power stages to a load current flowing through the load becomes a set value and the second mode controls the high side switch and the low side switch in each of the power stages so that duty ratios of the high side switch and the low side switch are equalized among the power stages.

A low-dropout voltage regulator includes a power transistor configured to receive an input voltage and to provide a regulated output voltage at an output voltage node. The power transistor includes a control electrode configured to receive a driver signal. A reference circuit is configured to generate a reference voltage. A feedback network is coupled to the power transistor and is configured to provide a first feedback signal and a second feedback signal. The first feedback signal represents the output voltage and the second feedback signal represents an output voltage gradient. An error amplifier is configured to receive the reference voltage and the first feedback signal representing the output voltage. The error amplifier is configured to generate the driver signal dependent on the reference voltage and the first feedback signal. The error amplifier includes an output stage that is biased with a bias current responsive to the second feedback signal.

A power control circuit for a power supply system including a control unit, a driving circuit and a power supply unit is disclosed. The power control circuit includes a current detection unit, a voltage detection unit and a power detection unit. The current detection unit is used for detecting a current signal. The voltage detection unit is used for detecting a voltage signal. The power detection unit is connected with the current detection unit, the voltage detection unit and the control unit for acquiring a power signal according to the current signal and voltage signal. By comparing an adjustable power reference signal with the power signal, the control unit issues a control signal to the driving circuit. In response to the control signal, the power supply unit is driven by the driving circuit to output an adjusted power to the load according to the adjustable power reference signal.

A mode controller shifts, along with increase in an electric power in first and second of chopper circuits and, operation modes of the first and the second of the chopper circuits from a first mode to a third mode via a second mode. An operation controller causes, in the first mode, the first of chopper circuit to perform an chopping operation, and the second of chopper circuit to suspend the chopping operation, in the second mode, causes the first and the second of chopper circuits to alternatively perform the chopping operations, and in the third mode causes both of the first and the second of chopper circuits to perform the chopping operations.

A counterbalance mechanism for counterbalancing weight of a bottom-hinged door (such as a clamshell-type airstair door of an aircraft) includes an operator handle, a hoist rod pivotally connected at one end to the operator handle and at an opposite end thereof to the door near a bottom region thereof. A force accumulator assembly is provided which includes a force biasing member which accumulates and dissipates a bias force when opening and closing the door, respectively, to provide mechanical counterbalance to the weight of the door. A bellcrank assembly operatively connects the operator handle to the force accumulator. In such a manner, weight counterbalancing of the door is achieved.

A device for accommodating objects, in particular for use in an airplane, comprises at least one panel. The panel has at least one outer edge which is provided with a rim in order to form a shock-absorbing edge. The rim comprises plastic that is integrally molded onto the outer edge of the panel. The device can be an airplane trolley, folding trolley, container or galley.

Baggage compartment 1 for an aircraft, wherein the baggage compartment 1 comprises a housing 2 and a baggage holder 3, wherein the baggage holder 3 is swivel-mounted about a swivel axis A in the housing 2, wherein, the swivel axis A intersects, in its longitudinal extent, a holder side wall 32 of the baggage holder 3 and/or a housing side wall 21 of the housing 2, wherein the baggage holder 3 can be moved from a closed position G into an open position Ö with a first swivel movement S1 and the baggage compartment 1 is opened and wherein the baggage holder 3 can be moved from the open position Ö into the closed position G with a second swivel movement S2 and the baggage compartment 1 is closed, wherein the baggage compartment 1 comprises a drive device 6 having at least one drive motor 9, wherein the drive device 6 is designed to drive the baggage holder 3 during the first and/or second swivel movement S1; S2 and to open or close the baggage compartment 1, wherein the drive device 6 is connected to the holder side wall 32 on one side and to the housing side wall 21 on the other side.

A radio controlled UAV is disclosed. The UAV includes a parachute, with a cylindrical power and control module suspended vertically below the parachute. In one embodiment, a propulsion source is mounted on top of the power and control module with control lines connected to the module below the propulsion source, and in another embodiment the power and control module is suspended from a point above a propulsion source. The UAV is controlled by radio controls from a hand held controller, with actuators retracting and letting out control lines attached to the parachute in order to control direction of the parachute. The UAV may be launched from a tube using a pressurized tank with a nozzle expelling gas from the tank, the tank and nozzle towing a canister from which the UAV is deployed.

A wing tip device for fixing to the outboard end of a wing, the wing defining a wing plane, includes: an upper wing-like element projecting upwardly with respect to the wing plane and having a trailing edge; and a lower wing-like element fixed with respect to the upper wing-like element and having a root chord and a trailing edge, the lower wing-like element root chord intersecting with the upper wing-like element, and the lower wing-like element projecting downwardly from the intersection. The upper wing-like element is larger than the lower wing-like element and the trailing edge of the lower wing-like element is adjacent the trailing edge of the upper wing-like element at the intersection. An included angle between the upper and lower wing-like elements at the intersection is less than, or equal to, 160 degrees.

Embodiments of an aerodynamic structural insert frame comprise a leading edge, a trailing edge opposite the leading edge, and at least one cavity between the leading edge and trailing edge, wherein the aerodynamic structural insert frame is configured to deflect upon activation by an external stimulus; at least one deformable buckling member extending the distance between opposite edges of the cavity, wherein the deflection of the aerodynamic structural insert frame is configured to trigger deflection of the deformable buckling member; a pivot region; and at least one stopper bar attached to and extending from one edge of the cavity a distance less than the distance between opposite edges of the cavity, wherein the stopper bar is configured to stop the deflection of the aerodynamic structural insert and the buckling member when the stopper bar strikes an opposite edge of the cavity.

An inceptor is provided including a control stick mounted to a seat. The control stick is movable about at least a first axis. A fly-by-wire inceptor control system is housed within a portion of the seat. The inceptor control system is configured to provide input signal indicative of movement of the control stick to a flight control system.

In a method for reducing the impact of a force upon a person seated in a safety seat of a motor vehicle at least a seat unit of the safety seat is restrained at least in part by at least one support strap. The support strap is formed with an extension piece configured to lengthen when exposed to a load as a result of an accident or explosion. A winding unit holds the support strap to shorten an effective length of the support strap and to build up a force to maintain the support strap under tension after the support strap underwent a lengthening in an area of the extension piece as a result of a load caused by a force resulting from an accident or explosion so as to reestablish an effective length of the support strap for lengthening during a subsequent force impact.

A method and apparatus for lighting a flight deck on an aircraft. A status of the aircraft is identified by a processor unit. The processor unit controls the lighting on the flight deck in response to the status of the aircraft to indicate the status of the aircraft.

Systems and methods for performing airport surface collision-avoidance. A wingtip-mounted camera allows the pilot to positively ascertain that the wingtip will clear objects located in the video. An exemplary system implemented on an aircraft includes a wingtip module having a camera that generates a video stream and a communication device that transmits the generated video stream. A processor receives the video stream and generates a reticule for the video stream. A display device simultaneously presents the video stream and the reticule. The reticule includes a horizon line and is based on a focal length of a lens of the camera and height of the camera above ground. The reticule includes curved and/or straight distance lines and curved or straight travel lines. The travel line(s) correspond to at least one aircraft component or a zone of importance and are based on location of the camera and trajectory of the aircraft.

A method of creating at least one flight plan of an aircraft includes entering a creation objective which illustrates a type and general characteristics of the flight plan to be created, automatically generating a flight plan outline, automatically generating a targeted request for information relating to missing parameters, entering the requested information relating to the missing parameters, and supplementing automatically the flight plan outline and automatically deleting any discontinuities to create, in a definitive manner, the flight plan.

The invention relates to a de-icing device for an element of a nacelle of a turbojet engine, including at least one heating resistant mat connected to at least one electrical power source (3) and thus defining an assembly (1) of resistant mats, characterized in that the assembly of resistant mats includes one or more subassemblies of resistant mats, each subassembly in turn including one or more resistant mats of the assembly, and each subassembly of resistive mats having a different ohmic value.

A method of controlling a group (2) of engines developing a necessary power (Wnec) for driving a rotor (3), said group (2) of engines having at least one electrical member (4), electrical energy storage means (5), and a first number n of engines (6) that is greater than or equal to two. A processor unit (10) executes instructions for evaluating a main condition as to whether the group of engines can develop the necessary power while resting one engine, and if so for resting one engine and accelerating a second number engines not at rest, and for causing the electrical member to operate in motor mode, if necessary, the electrical member operating temporarily in electricity generator mode when the storage means are discharged.

A rotor system is disclosed for a reactive drive rotary wing aircraft. Apparatus and methods are disclosed for maintaining the rigidity of the rotor and eliminating play between flight controls and the rotor by mounting swashplate actuators to a flange rigidly secured to the mast. Methods are disclosed for modulating the temperature of oil pumped over one or more of the mast bearing, swashplate bearing, and spindle bearing. The temperature of air passively or actively drawn through rotor may also be modulated to maintain bearing temperature within a predetermined range. Structures for reducing pressure losses and drag on components due to air flow through the rotor are also disclosed. A rotor facilitating thermal management by oil and air flow is also disclosed. Surfaces interfacing between the swashplate and the mast and between control rods and the swashplate or pitch horn may bear a solid lubricant layer.

An integrated aircraft galley structure includes a service module having a plurality of galley inserts including at least one oven and at least one refrigeration unit. The service module is formed with a plurality of bays sized to receive the plurality of galley inserts, along with a human machine interface for controlling all of the galley inserts. The service module further includes a plurality of galley insert modules for controlling each galley insert, and an insert power and control unit for each galley insert for controlling power to said insert. The entire system is controlled by a galley power and control unit for controlling each of the insert galley power and control units, and an AC distribution unit for distributing power to the insert power and control units.

A space efficient lavatory module for commercial aircraft includes an aft facing concave wall recess that provides a greater distance from an upper, forward facing portion of a cabin structure, such as an aircraft passenger seat to avoid having a passenger's head impact the aft facing lavatory or enclosure wall in a sudden aircraft deceleration. The aft facing concave wall recess also provides space for mounting of a protective cushion, in order to reduce a passenger's risk of head trauma in a sudden deceleration, as well as other items, such as a video monitor, a bassinet or infant bed, without inhibiting passenger movement.

In conventional aircraft cargo compartments panels or similar flat floor elements are fastened to floor beams or similar supporting elements that are installed in the body of the aircraft. Subsequently functional units such as roller elements, latches or PDUs are mounted and connected to one another by way of appropriate control conductors. It is proposed to fasten the floor elements permanently to the supporting beams so as to form prefabricated floor modules and to install these floor modules in the aircraft.

A headrest assembly (1) for an ejection seat, comprising: a support mounting (2); and a pair of inflatable side beams (3), each attached at one end to the support mounting and spaced apart from one another, the side beams (3) being configured to be inflated from a stowed configuration to a deployed configuration in which the side beams extend from the support panel, the side beams (3) configured to deploy through: a capturing phase, during which the side beams are partially inflated from the stowed configuration such that they extend outwardly and upwardly from the support mounting and away from one another to surround the head of an occupant of the ejection seat toward a central location with respect to the support mounting.

An assembly for shielding an aircraft from electromagnetic energy may include a window mounting configured to be conductively coupled to an aperture in a fuselage of an aircraft. The window mounting may include a window pane having an electromagnetically-reflective coating for reflecting electromagnetic energy. The window pane may remain electrically isolated from the fuselage prior to the electromagnetic energy exceeding a frequency of approximately 1 GHz. The window mounting may further include a capacitive gasket capacitively coupling the window pane to the fuselage after the frequency of the electromagnetic energy reflected by the window pane exceeds approximately 1 GHz.

An arrangement of aerodynamic auxiliary surfaces is configured for being arranged on the underside of an aircraft and furthermore includes a longitudinal axis and at least one aerodynamic auxiliary surface, wherein the aerodynamic auxiliary surface is laterally offset referred to the longitudinal axis, and wherein the aerodynamic auxiliary surface is configured for generating vortices when it is subjected to an oncoming air flow. This makes it possible to compensate vortices caused by the shape of the aircraft such that the directional stability of the aircraft can be improved and the aerodynamic drag may be reduced.

According to one embodiment, a windshield attachment device for coupling a windshield to a body includes a fastener portion, a bolt, and an elastomeric load isolator. The fastener portion has an opening therethrough. The bolt is configured to extend through the opening of the fastener portion and couple the fastener portion to the body. The elastomeric load isolator surrounds at least a portion of the fastener portion and separating the fastener portion from the windshield.

A method and apparatus comprising a refueling controller. The refueling controller is configured to receive data about a current rate of movement of a refueling boom while the refueling boom is in contact with a receiver aircraft during flight. The refueling controller is further configured to disconnect the refueling boom from the receiver aircraft based on the current rate of movement of the refueling boom and a current position of the refueling boom.

Certain embodiments described herein are directed to devices configured to retain, at least for some period, and provide pre-launch support kites such as stunt kites. In certain instances, the device positions stunt kites of various sizes and design, including, for example, delta wing kits, diamond kits and foil kits, in a reclined position to provide pre-launch stability and wind flow/spill-over across the face of the kite to help prevent unintentional or premature launch. If desired, optional control line upright supports can be present that permit minimum control line pull-back thereby reducing the recline of the kite to bring the face of the kite into the wind and thereby launch the kite. The control line upright supports may also prevent the kite from falling completely face down on the surface, thereby requiring a reset of the kite on the device.

A system has a plurality of spacecraft in orbit around the earth for collecting energy from the Sun in space, using stimulated emission to configure that energy as well defined states of the optical field and delivering that energy efficiently throughout the region of space surrounding Earth.

Methods and apparatus are presented for spacecraft operation using non-Eigen axis attitude transitions via control momentum gyroscopes (CMGs) to avoid or mitigate singularities by providing a time-varying attitude command vector including a plurality of time-varying attitude command signals or values representing a plurality of spacecraft states and control trajectories as a guidance command input to an attitude controller of the spacecraft without modifying the spacecraft feedback control law.

A space debris remover aiming to remove a space debris object in earth orbits. Angular thrust calculation unit calculates angular thrust. Radial thrust calculation unit calculates radial thrust based on the angular thrust, estimated angular momentum and estimated space debris mass. A foam bonding mechanism connects the space debris remover and the space debris object. A space debris removal controller calculates firing time, and sends a space debris removal control signal comprising the radial thrust, the angular thrust and the firing time. A plurality of first stage thrusters generate the radial thrust and the angular thrust after the firing time. After the stage separator separates a first stage and a second stage of the space debris remover, a plurality of second stage thrusters generate the radial thrust and the angular thrust, and propel the space debris object towards the sun.

A device for thermal monitoring a piece of equipment, which is integrated on a craft placed in a forced vacuum environment, an outside part of the equipment projecting outside of a wall of the craft and being subjected to a solar radiation flux, includes an absorbent screen that is suitable for being placed between the outside part of the equipment and the wall of the craft, whereby this absorbent screen has—on at least one portion of its front face, designed to be placed on the side removed from the wall of the craft—an absorptivity αSOLAR that is the largest possible in the field of solar radiation, coupled to a low emissivity εIR in the infrared spectrum. The absorbent screen is made of a very heat-conductive material and has—on at least a portion of its rear face, suitable for being oriented toward the wall of the craft—a high emissivity εIR in the infrared spectrum, typically greater than or equal to 0.7.

A method for simulating the movement behavior of a fluid in a closed moving container is provided. The simulation is based on the determination of the potential movement path of the center of gravity of the volume of the fluid as an elliptical trajectory situated in a disturbance plane having certain semi-axes.

A system and method for mitigating an aircraft incident is provided. The invention includes an aircraft panic component coupled to a terminal component. The aircraft panic component facilitates identification of a panic situation and communicates information associated with the panic situation to the terminal component. The aircraft panic component is further operative to at least partially disable a navigation system and/or operational system of an aircraft. The aircraft can then be sent to a safe zone, navigated remotely and/or a course of action for the aircraft can be determined. A safe zone component is adapted to facilitate identification of a course of action for the aircraft based at least in part upon aircraft positional information, aircraft condition information and/or aircraft resource(s). Further, aircraft navigational information and/or aircraft operational information can be sent via an aircraft communication component to a remote system having a remote communication component and a remote analyzing component facilitating transfer of information related to navigational and/or operational system(s) of the aircraft.

The spiroid wing tip according to embodiments of the invention including a continuous segmental assembly having a closed loop frontal profile comprising a lower near vertical segment, a horizontal segment, a vertical segment, a second horizontal upper segment, and a near vertical segment. Accordingly to some embodiments of the invention, the spiroid profile is lowered with respect to the wing chord plane, such that a portion of the spiroid wing tip extends below the wing chord plane.

A variable length light shield is disclosed for an electro-optical sensor within a nose cone. The light shield includes a base, a telescopic shade supported by the base, and a ring rotatably supported about the base. The light shield also includes a guide tube disposed proximate the ring with an end extending away from the ring about a side of the telescopic shade. The light shield further includes an extension spring supported by the guide tube with an end coupled to the telescopic shade. Additionally, the light shield includes a cable extending through the guide tube and the extension spring, with one end of the cable coupled to the ring and another end of the cable coupled to the telescopic shade. The extension spring is configured to exert a force on the telescopic shade to extend the telescopic shade. Rotation of the ring causes retraction of the telescopic shade.