2-4
1. Feature of CCD for this model
This CCD adopts the drive frequency and the number of pixels conforming to the DVC format. The
horizontal drive frequency is 18MHz based on 13.5MHz that is Y signal sampling frequency of the DVC
format. And the number of pixels secures the horizontal resolution of 400 lines that conforms to the high
resolution DVC format. Moreover, to keep resolution even if EIS is switched on, the CCD having EIS
(Electric Image Stabilizer) area (approx. 33% in area) is adopted.
Adoption of the usual 1/4”-type CCD realizes miniaturization of the lens unit with keep the zoom ratio of 10
times, and it also realizes miniaturization of whole body.
On the other hand, a pixel size gets smaller as the evil effect of miniaturization and large numbers of pixel.
It becomes unfavorable in the point of CCD sensitivity and dynamic range. For such reason, the minimum
object illumination is determined as 18 Lux EIA standard.
2. Improvement of the CCD for DVC
It is elaborated the following idea to make up for the decline of the sensitivity of CCD at all.
1) Optimization of the on-chip microlens
Loss of incident light is minimized by reduction of ineffective area between microlenses on the pixels.
Photo
shielding AI
Light
Ineffective
Effective
Transfer
section
On-chip microlens On-chip microlens
Sensor
Transfer
section
Ineffective
Light
Photo
shielding AI
Transfer
section
Transfer
section
Effective
Fig. 2-2-3 Structural drawing of CCD image sensor
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