Optical sensing circuit and method for determining light color by using the same

An optical sensing circuit, comprising:

• a capacitor;
• a light sensing unit, electrically connected to the capacitor, wherein the light sensing unit comprises a first light sensing transistor and is configured to sense a first color;
• a compensation unit, electrically connected to the capacitor, wherein the compensation unit comprises a second light sensing transistor and is configured to sense a second color, the spectrum of the second color and the spectrum of the first color do not overlap with each other;
• a switching element, electrically connected to the capacitor;
• wherein when a light illuminates the light sensing unit and the compensation unit, a first light component of the light corresponding to the first color causes the light sensing unit to generate a first current, and a second light component of the light corresponding to the second color causes the compensation unit to generate a second current, the second current reduces the magnitude of the charging current or the discharging current when the capacitor is charged or discharged by the first current;
• wherein when the switching element is turned on, the voltage of the capacitor is read and used as information for determining the color of the light;
• wherein the first light sensing transistor and the second light sensing transistor are diode-connected thin film transistors.

A method for determining light color using an optical sensing circuit, comprising:

• providing an optical sensing circuit, the optical sensing circuit comprising a capacitor, a light sensing unit, a compensation unit, and a switching element, wherein the light sensing unit, electrically connected to the capacitor, comprises a first light sensing transistor and is configured to sense a first color, the compensation unit, electrically connected to the capacitor, comprises a second light sensing transistor and is configured to sense a second color, the spectrum of the second color and the spectrum of the first color do not overlap with each other, the switching element is electrically connected to the capacitor, one end of the first light sensing transistor receives an operating signal, and the switching element is controlled by a control signal;
• making the operating signal having a first voltage for initializing the voltage value of the capacitor during an initial period;
• making the operating signal having a second voltage during a sensing period, when the light illuminates the light sensing unit and the compensation unit, the first light component of the light corresponding to the first color causes the light sensing unit to generate a first current, and the second light component of the light corresponding to the second color causes the compensation unit to generate a second current, the second current reduces the magnitude of the charging current or the discharging current when the capacitor is charged or discharged by the first current;
• enabling the scan signal during a sampling period, such that the switching element is turned on and the voltage of the capacitor is read and used as an information for determining the color of the light;
• wherein the voltage level of at least one of the gate of the first light sensing transistor and the gate of the second light sensing transistor is adjustable.

A method for determining light color using an optical sensing circuit, comprising:

• providing an optical sensing circuit, the optical sensing circuit comprising a capacitor, a light sensing unit, a compensation unit, and a switching element, wherein the light sensing unit, electrically connected to the capacitor, comprises a first light sensing transistor and is configured to sense a first color, the compensation unit, electrically connected to the capacitor, comprises a second light sensing transistor and is configured to sense a second color, the spectrum of the second color and the spectrum of the first color do not overlap with each other, the switching element is electrically connected to the capacitor, one end of the first light sensing transistor receives an operating signal, and the switching element is controlled by a control signal;
• making the operating signal having a first voltage for initializing the voltage value of the capacitor during an initial period;
• making the operating signal having a second voltage during a sensing period, when the light illuminates the light sensing unit and the compensation unit, the first light component of the light corresponding to the first color causes the light sensing unit to generate a first current, and the second light component of the light corresponding to the second color causes the compensation unit to generate a second current, the second current reduces the magnitude of the charging current or the discharging current when the capacitor is charged or discharged by the first current;
• during a sampling period, enabling the scan signal, such that the switching element is turned on and the voltage of the capacitor is read and used as an information for determining the color of the light;
• wherein the first light sensing transistor and the second light sensing transistor are diode-connected thin film transistors.