Polarity switching power supply device

A camera, comprising:

• an image sensor;
• a liquid crystal display (LCD) panel optically intermediate the image sensor and a scene, the LCD panel including a positive input node and a negative input node, and
• a power supply device, comprising:
• a voltage source configured to generate an input voltage;
• a positive output node electrically connected to the positive input node of the LCD panel;
• a negative output node electrically connected to the negative input node of the LCD panel;
• a positive-side switching converter electrically connected between the voltage source and the positive output node;
• a negative-side switching converter electrically connected between the voltage source and the negative output node;
• and
• a controller configured to:
• in an active-bias mode, alternate a polarity of a bias voltage across the positive output node and the negative output node by alternating between a forward-bias state and a reverse-bias state, such that the LCD panel transmits light inside and outside of a designated wavelength range from the scene to the image senor;
• and
• in a neutral-bias mode, provide a neutral bias voltage across the positive-side output node and the negative-side output node, such that the LCD panel blocks light from the scene in the designated wavelength range from reaching the image sensor.

A head-mounted device, comprising:

• a frame;
• an outward-facing camera mounted on the frame and configured to image a scene, the outward-facing camera comprising:
• an image sensor;
• a liquid crystal display (LCD) panel optically intermediate the image sensor and the scene, the LCD panel including a positive input node and a negative input node, and
• a power supply device, comprising:
• a voltage source configured to generate an input voltage;
• a positive output node electrically connected to the positive input node of the LCD panel;
• a negative output node electrically connected to the negative input node of the LCD panel;
• a positive-side switching converter electrically connected between the voltage source and the positive output node;
• a negative-side switching converter electrically connected between the voltage source and the negative output node;
• and
• a controller configured to:
• in an active-bias mode, alternate a polarity of a bias voltage across the positive output node and the negative output node by alternating between a forward-bias state and a reverse-bias state, such that the LCD panel transmits light inside and outside of a designated wavelength range from the scene to the image senor;
• and
• in a neutral-bias mode, provide a neutral bias voltage across the positive output node and the negative output node, such that the LCD panel blocks light from the scene in the designated wavelength range from reaching the image sensor.