US4035607A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Integrated heater element array
Assignee: International Business Machines Corp
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Filing: 1976-03-19
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Granted: 1977-07-12
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Expires: 1996-03-19
Abstract
Abstract A thermal display comprising an array of semiconductor heater mesas having a larger cross-sectional area at the display surface than at the support surface. The preferred structure is in the shape of a truncated, inverted pyramid. The novel method includes forming the inverted heater elements by etching trenches in one surface of the semiconductor substrate and forming the heater mesas at the opposite surface, with the trenches defining the individual mesas.
Inventors
- 👤 Leon L. Wu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 08:06
CPC Classifications
B; B41; B41J; B41J2/00; B41J2/315; B41J2/32; B41J2/335; B41J2/34
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
66 words
A semiconductor thermal printing device including a semiconductor substrate and a plurality of spaced semiconductor heating elements formed on a major surface of said semiconductor substrate and having common coplanar faces in electrical and thermal isolation from each other, the improvement wherein: the area of the face of said heating elements opposite said semiconductor substrate is larger than the area of the face adjacent said substrate.
Claim 2
Dependent Claim
66 words
A semiconductor thermal printing device including a semiconductor substrate and a plurality of spaced semiconductor heating elements formed on a major surface of said semiconductor substrate and having common coplanar faces in electrical and thermal isolation from each other, the improvement wherein: the area of the face of said heating elements opposite said semiconductor substrate is larger than the area of the face adjacent said substrate.
Claim 3
Dependent Claim
21 words
A thermal printing device as in claim 1 wherein the shape of said heating element is substantially an inverted truncated pyramid.
Claim 4
Dependent Claim
32 words
A thermal printing device as in claim 2 wherein the substrate is silicon and the crystallographic orientation of said substrate is selected from the group consisting of the (100) and (111) orientations.
Claim 5
Dependent Claim
30 words
A thermal printing device according to claim 1 wherein the thermal isolation between said heating elements is provided by a thermal insulating material which fills the spaces between said elements.
Claim 6
Dependent Claim
29 words
A thermal display system according to claim 1 wherein: said semiconductor substrate contains switching circuits for selectively energizing said heating elements, said circuits being isolated from said heating elements.
Claim 7
Dependent Claim
29 words
A thermal display device as in claim 5 wherein said circuit elements comprise: a plurality of transistor switch means, each being associated individually with one of said heating elements.
Claim 8
Dependent Claim
54 words
A thermal display device as in claim 6 wherein each said transistor switch means functions as a constant current source for its associated heating element and comprises: a bipolar transistor; a resistor; the collector of said transistor being connected to said heating element; and the emitter of said transistor being connected to said resistor.
Claim 9
Dependent Claim
44 words
A thermal display device as in claim 7 wherein the connector between said transistor collector and said heating element comprises a highly doped conductive region extending from the face of said heating element adjacent said substrate to the opposite major surface of said substrate.
Claim 10
Dependent Claim
42 words
A thermal printing device as in claim 1 wherein: the substrate is silicon; the crystallographic orientation of said substrate is (100); and said trenches are in the <012> and <021> crystallographic directions in said substrate, whereby said mesas have sharp, well-defined corners.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-07-11 | 1981-01-10 | 1981-07-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-07-11 | 1985-01-10 | 1985-07-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-07-11 | 1989-01-10 | 1989-07-12 | $7700.00 | Window Closed / Lapsed |