---
title: "CCD imaging: move the charge before measuring it"
description: "How did a clocked chain of charge wells turn an optical exposure into an electrical image?"
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last_modified: "2026-10-23"
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[Materials that control current and light](https://sandboxphysics.com/stories/condensed-matter/#devices)

Materials · Measurements · Explanation

# CCD imaging: move the charge before measuring it

How did a clocked chain of charge wells turn an optical exposure into an electrical image?

Sandbox Physics · 2026-10-23

Nobel contribution: 2009-2

1. Convert absorbed light to charge
2. Store packets in potential wells
3. Clock packets toward an output
4. Amplify and digitize each packet

Optical collection, charge transfer and electrical readout contribute different losses and noise.

## The 1969 idea was clocked charge storage

Boyle and Smith conceived the charge-coupled device in 1969, initially in a memory context. Voltages on neighboring gates reshape potential wells, moving stored charge without giving each pixel its own amplifier.

Its imaging use combined that transport mechanism with photoelectric charge generation. Later sensor development turned the idea into practical cameras; the Nobel award in 2009 recognizes the CCD invention.

Sources: [1] [2]

## Exposure and readout happen in different stages

During exposure, a pixel collects electrons from absorbed photons, together with dark charge. During readout, a sequence of clocks passes the packet through neighboring wells and a serial register to an amplifier. Pixel order is carried by that sequence.

Sources: [1]

## Small transfer errors accumulate

Traps can delay electrons, leaving a trail behind a bright packet. Even excellent per-transfer efficiency compounds over many shifts. Read noise is added at the amplifier, so it is distinct from charge lost or deferred during transport.

Sources: [1]

## The new Lab follows each packet to the amplifier

The CCD Lab displays phased gates and charge transport, then compares stored packets with read samples. Its synthetic transfer and noise controls isolate those stages. Lens focusing belongs to the existing camera-optics work and is not rebuilt here.

Sources: [1] [3]

Continue with the physics

## Try the related models

### [CCD charge transfer](https://sandboxphysics.com/labs/ccd-charge-transfer/)

Follow charge packets through clocked gates to the output amplifier.

The transfer model omits a camera lens and does not reproduce a manufacturer’s image sensor.

## Sources and reading notes

1. [2009 Nobel scientific background: semiconductor image sensors](https://www.nobelprize.org/uploads/2018/06/advanced-physicsprize2009-1.pdf)

   Clocked charge transfer, serial readout, quantum efficiency and noise are different stages of imaging.

2. [Boyle: interview about the 1969 CCD idea](https://www.nobelprize.org/prizes/physics/2009/boyle/interview/)

   First-person recollection; the initial memory concept and subsequent imaging development are separated.

3. [Nobel Prize in Physics 2009: official award](https://www.nobelprize.org/prizes/physics/2009/summary/)

   Official attribution and award year. The observation or theoretical paper may be much earlier.

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