Image sensors, image detecting systems including the image sensors, and methods of operating the image sensors

An image detecting system comprising:

• a light source configured to emit an irradiation light in response to a first clock signal;
• an image sensor including a pixel, which is configured to sense a fraction of the irradiation light reflected by a subject and is configured to produce an image signal in response to the first clock signal and a second clock signal during a sensing period, the first and second clock signals having opposite phases during the sensing period;
• and
• a processor configured to calculate a distance between the image sensor and the subject, based on the image signal,
• wherein the pixel comprises:
• a charge collection circuit configured to collect first charges, which are produced by an incident light, in response to the first clock signal, and configured to collect second charges, which are produced by the incident light, in response to the second clock signal, during the sensing period;
• a floating diffusion region;
• a storage transistor configured to store the first charges or the second charges during the sensing period and configured to transfer at least a portion of the first charges or at least a portion of the second charges to the floating diffusion region, based on a voltage level of a storage control signal that is applied to a gate of the storage transistor;
• and
• a read circuit configured to produce the image signal, based on the at least the portion of the first charges or the at least the portion of the second charges transferred to the floating diffusion region,
• wherein the storage transistor is configured to have a first charge storage capacity during the sensing period and is configured to have a second charge storage capacity during the transfer of the at least the portion of the first charges or the at least the portion of the second charges to the floating diffusion region, and
• wherein the first charge storage capacity is higher than the second charge storage capacity.

A method of operating an image sensor, wherein the image sensor comprises a pixel configured to generate an image signal in response to an incident light, and wherein the pixel comprises a storage transistor and a floating diffusion node, and

• wherein the method comprises:
• collecting charges, which are produced by the incident light, in the pixel;
• storing the charges in the storage transistor, in response to a first storage control signal applied to a gate of the storage transistor, during the collecting of the charges in the pixel;
• transferring the charges to the floating diffusion node, in response to a second storage control signal having a voltage level lower than the first storage control signal;
• and
• producing the image signal, based on the charges transferred to the floating diffusion node,
• wherein the storage transistor has a first charge storage capacity during the collecting of the charges in the pixel and has a second charge storage capacity during the transferring of the charges to the floating diffusion node, and
• wherein the first charge storage capacity is higher than the second charge storage capacity.