US6066883A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Guarding for a CMOS photosensor chip
Assignee: Majandro LLC
•
Filing: 1998-03-16
•
Granted: 2000-05-23
•
Expires: 2018-03-16
Abstract
Abstract In a CMOS-based photosensor chip, the area between the last photosensor in a linear array of photosensors and the edge of the chip can be a source of unintended charge generation affecting the last photosensor. A guardring, in the form of a biased diffusion area, prevents the unwanted leakage of charge from the edge area to the end photosensor.
Inventors
- 👤 Paul A. Hosier
- 👤 Jagdish C. Tandon
- 👤 Scott L. Tewinkle
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-10 00:41
CPC Classifications
H; H10; H10F; H10F39/00; H10F39/10; H10F39/12; H10F39/18; H10F39/80; H10F39/805; H10F39/8057
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
61 words
A photosensitive chip defining a main surface and an edge of the main surface, comprising: a photosensor defined on the main surface, the photosensor defining a perimeter; a guardring, at least a portion of the guardring being disposed between the photosensor and the edge, the guardring including a diffusion layer; and a light shield disposed between the photosensor and the edge.
Claim 2
Dependent Claim
61 words
A photosensitive chip defining a main surface and an edge of the main surface, comprising: a photosensor defined on the main surface, the photosensor defining a perimeter; a guardring, at least a portion of the guardring being disposed between the photosensor and the edge, the guardring including a diffusion layer; and a light shield disposed between the photosensor and the edge.
Claim 3
Dependent Claim
28 words
The chip of claim 1, the guardring defining a width along a dimension between the perimeter of the photosensor and the edge of no more than three micrometers.
Claim 4
Dependent Claim
18 words
The chip of claim 1, wherein the photosensor includes a collection region, the collection region defining a width.
Claim 5
Dependent Claim
29 words
The chip of claim 3, the guardring defining a width along a dimension between the photosensor and the edge which is less than the width of the collection region.
Claim 6
Dependent Claim
20 words
The chip of claim 4, the guardring defining a width of less than one-half the width of the collection region.
Claim 7
Dependent Claim
12 words
The chip of claim 1, further comprising means for biasing the guardring.
Claim 8
Dependent Claim
27 words
The chip of claim 6, the means for biasing the guardring biasing the guardring at less than one-half the maximum bias of any element of the chip.
Claim 9
Dependent Claim
26 words
The chip of claim 1, the photosensor including a collection diffusion, and further comprising means for biasing the guardring and means for biasing the collection diffusion.
Claim 10
Dependent Claim
28 words
The chip of claim 8, the means for biasing the guardring biasing the guardring at no more than one volt difference from a bias on the collection diffusion.
Claim 11
Dependent Claim
79 words
A photosensitive chip defining a main surface and an edge of the main surface, comprising: a photosensor defined on the main surface, the photosensor including a collection diffusion, the collection diffusion defining a width; a guardring, at least a portion of the guardring being disposed between the photosensor and the edge; and means for independently biasing at least one of the collection diffusion and the guardring to allow net zero current flow between the collection diffusion and the guardring.
Claim 12
Dependent Claim
79 words
A photosensitive chip defining a main surface and an edge of the main surface, comprising: a photosensor defined on the main surface, the photosensor including a collection diffusion, the collection diffusion defining a width; a guardring, at least a portion of the guardring being disposed between the photosensor and the edge; and means for independently biasing at least one of the collection diffusion and the guardring to allow net zero current flow between the collection diffusion and the guardring.
Claim 13
Dependent Claim
29 words
The chip of claim 10, the guardring defining a width along a dimension between the photosensor and the edge which is less than the width of the collection diffusion.
Claim 14
Dependent Claim
20 words
The chip of claim 11, the guardring defining a width of less than one-half the width of the collection diffusion.
Claim 15
Dependent Claim
31 words
The chip of claim 10, the means for biasing the collection diffusion and the guardring biasing the guardring at less than one-half the maximum bias of any element of the chip.
Claim 16
Dependent Claim
28 words
The chip of claim 10, the means for biasing the guardring biasing the guardring at no more than one volt difference from a bias on the collection diffusion.
Claim 17
Dependent Claim
87 words
A photosensitive chip defining a main surface and an edge of the main surface, comprising: a photosensor defined on the main surface, the photosensor including a collection diffusion, the collection diffusion defining a width; a guardring, at least a portion of the guardring being disposed between the photosensor and the edge, the guardring including a diffusion layer electrically separate from the collection diffusion, the guardring defining a width along a dimension between the photosensor and the edge which is less than the width of the collection diffusion.
Claim 18
Dependent Claim
87 words
A photosensitive chip defining a main surface and an edge of the main surface, comprising: a photosensor defined on the main surface, the photosensor including a collection diffusion, the collection diffusion defining a width; a guardring, at least a portion of the guardring being disposed between the photosensor and the edge, the guardring including a diffusion layer electrically separate from the collection diffusion, the guardring defining a width along a dimension between the photosensor and the edge which is less than the width of the collection diffusion.
Claim 19
Dependent Claim
20 words
The chip of claim 15, the guardring defining a width of less than one-half the width of the collection diffusion.
Claim 20
Dependent Claim
34 words
The chip of claim 15 further comprising means for independently biasing at least one of the collection diffusion and the guardring to allow net zero current flow between the collection diffusion and the guardring.
Claim 21
Dependent Claim
18 words
The chip of claim 15, further comprising a light shield disposed between the collection diffusion and the edge.
Claim 22
Dependent Claim
19 words
The chip of claim 15, the collection diffusion occupying only a portion of a light-collection area of the photosensor.
Claim 23
Dependent Claim
20 words
The chip of claim 19, the collection diffusion forming an annular collection region within the light-collection area of the photosensor.
References Cited (Backward Citations)
US4458260A
Cited
US4536658A
Cited
US4651187A
Cited
US4548671A
Cited
US4687537A
Cited
US5614744A
Cited
US5696626A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2003-05-23 | 2003-11-22 | 2004-05-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-05-23 | 2007-11-22 | 2008-05-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-05-23 | 2011-11-22 | 2012-05-23 | $7700.00 | Window Closed / Lapsed |