Self-scanning light-emitting array and a driving method of the array

• US 5,451,977 A
• Filed: 06/28/1993
• Issued: 09/19/1995
• Est. Priority Date: 03/18/1988
• Status: Expired due to Term

• Current Assignee: Fuji Xerox Company Limited (Xerox Holdings Corp.)
• Original Assignee: Nippon Sheet Glass Company Limited (Nippon Telegraph and Telephone Corporation)
• Inventors: Yamashita, Ken, Kusuda, Yukihisa, Tanaka, Shuhei, Tone, Kiyoshi
• Primary Examiner(s): Weldon, Ulysses
• Assistant Examiner(s): WU, XIAO MIN
• Application Number:
  US08/084,766
• Time in Patent Office: 813 Days
• Field of Search: 340/782, 340/762, 340/766, 340/719, 340/718, 358/475, 358/482, 358/483, 307/13, 307/461, 307/464, 257/21, 257/22, 257/80, 257/81, 257/82, 257/83, 257/84, 345/39, 345/44, 345/46, 345/82, 345/84, 345/205, 345/206, 345/214, 345/215
• US Class Current: 345/44
• CPC Class Codes: B41J 2/45 using light-emitting diode [LED] or laser arrays
• CPC Class Codes: B41J 2002/453 self-scanning
• CPC Class Codes: G06K 15/1247 using an array of light sources, e.g. a linear array
• CPC Class Codes: H01L 27/153 in a repetitive configuration, e.g. LED bars
• CPC Class Codes: H01L 27/156 two-dimensional arrays
• CPC Class Codes: H01L 33/0004 Devices characterised by their operation
• CPC Class Codes: H01S 5/4018 Lasers electrically in series
• CPC Class Codes: H01S 5/4025 Array arrangements, e.g. constituted by discrete laser diodes or laser bar H01S5/42 takes precedence
• CPC Class Codes: H01S 5/4031 Edge-emitting structures

Abstract

A self-scanning light-emitting element array is disclosed. A coupled array of light-emitting elements is constituted so that a light-emitting element which is turned on influences a light-emitting element to be turned on next so that its threshold level is changed. When each element is clock-driven by a common drive pulse, the change in threshold level is shifted in the array direction, so that a turn-on operation is transferred in a clock period of the drive pulse.

Claims

1. A self-scanning light-emitting element array comprising:

an array of pnpn light-emitting elements disposed with a predetermined pitch along a longitudinal direction and separated by a grooved structure provided on said pnpn structure, integral to a common cathode layer and each having an anode and a gate for controlling its turn-on threshold;

a first insulating film covering the entire upper surface of said grooved structure, said film having a plurality of contact holes therein;

a plurality of crosswise electrodes provided on said first insulating film and each connected to said anode through a contact hole provided in said first insulating film;

a plurality of coupling means each of which is coupled between said gates of neighboring light-emitting elements through said contact holes

a second insulating film covering the whole upper surface of said first insulating film having another set of contact holes therein; and

first, second and third longitudinal clock lines provided on said second insulating film, each connected via said crosswise electrode through said contact holes in said second insulating film to said anodes of said first, second and third groups of said light-emitting elements in every third fashion.

2. An array according to claim 1, in which said coupling means consist of a resistor integral to said p or n layer connected between said gates of adjacent light-emitting elements.

3. An array according to claim 1, in which said coupling means comprises a 2-dimensional thin film resistor provided on said insulating film and connected to said gates of adjacent light-emitting elements through equidistant aligned contact holes provided in said first insulating film.

4. An array according to claim 1 further comprising;

a plurality of pull-up means includes separated p- or n-layers of the remaining npnp structure each coupled to said gate of said light-emitting element through a contact hole provided in said first insulating film; and

a longitudinal bias line for supplying said bias current to said gates of said light-emitting elements through said pull-up means.

5. A self-scanning light-emitting element array comprising:

an array of pnpn light-emitting elements disposed in a line with a predetermined pitch along a longitudinal direction and separated by a groove provided on said pnpn structure, integral to a common cathode layer and each having an anode and a gate for controlling its turn-on threshold;

an insulating film covering the entire upper surface of the grooved structure;

a plurality of uni-directional coupling means provided on respective portions of said light-emitting elements partitioned by second grooves, respectively, each coupled to the next gate of said light-emitting elements via an electrode provided on said insulating film through a contact hole provided in said insulating film; and

first and second longitudinal clock lines provided on said insulating film, each connected through another contact hole provided in said insulating film to said anodes of said every other light-emitting elements.

6. An array according to claim 5, in which said uni-directional coupling means comprises a diode connected between said first gates.

7. An array according to claim 5, in which said light-emitting elements have a second gate;

and

said uni-directional coupling means comprises a transistor having a base connected to said first gate of one of said light-emitting elements, a collector integral to said one of said light-emitting elements and an emitter connected to said first gate of said neighboring light-emitting element.

8. An array according to claim 5, in which said light-emitting elements have a second gate;

and

said uni-directional coupling means comprises an emitter grounded transistor having a base connected to said second gate of one of said light-emitting elements and a collector connected to said first gate of said neighboring light-emitting element.

9. An array according to claim 5, further comprising:

a plurality of crosswise electrodes provided on said insulating film, each connected to said anode through said contact hole and to one of said first and second longitudinal clock lines in every other fashion through a second contact hole provided in a second insulating film covering said insulating film;

a plurality of pull-up means each coupled to said gate of said light-emitting element through a contact hole provided in said insulating film; and

a longitudinal bias line for supplying said bias current to said gates of said light-emitting elements through said pull-up means.

10. A self-scanning light-emitting element array comprising:

an array of cathode-common light-emitting elements disposed with a predetermined pitch along a longitudinal direction and separated by a groove provided on a multilayer structure, and each having an anode and a gate;

a first insulating film covering the entire upper surface of the grooved multilayer structure;

a plurality of crosswise electrodes provided on said first insulating film and each connected to said anode through a contact hole provided in said first insulating film;

a plurality of coupling means each coupled between said gates of neighboring light-emitting elements through said contact holes;

a second insulating film covering the entire upper surface of said first insulating film;

first, second and third longitudinal clock lines provided on said second insulating film, each connected through another contact hole provided in said insulating film to said anodes of said first, second and third light-emitting elements in every third fashion via said crosswise electrode;

first, second and third phase pulses having leading and trailing edge portions applied to said first, second and third longitudinal clock lines, respectively and said trailing edge portion of said phase pulse being overlapped to said leading edge portion of the next said phase pulse for transferring an ON state of said light-emitting elements; and

three controllable current sources connected to said first, second and third longitudinal clock lines, respectively and controlled synchronously with said phase pulses for supplying an additional current to said ON state light-emitting element.

11. An array according to claim 10 further comprising:

a plurality of pull-up means includes separated p- or n-layers of the remaining multilayer structure each coupled to said gate of said light-emitting element through a contact hole provided in said first insulating film; and

a longitudinal bias line for supplying said bias current to said gates of said light-emitting elements through said pull-up means.

12. A self-scanning light-emitting element array comprising:

an array of cathode-common light-emitting elements disposed with a predetermined pitch along a longitudinal direction and separated by a groove provided on a multilayer structure, and each having an anode and a gate;

a first insulating film covering the entire upper surface of the grooved structure;

a plurality of uni-directional coupling means provided on respective portions of said light-emitting elements partitioned by second grooves, respectively, each coupled to the next gate of said light-emitting elements via an electrode provided on said insulating film through another contact hole provided in said insulating film;

first and second longitudinal clock lines each connected to said anodes of said first and second light-emitting elements in every other fashion;

first and second phase pulses having leading and trailing edge portions applied to said first and second longitudinal clock lines, respectively and said trailing edge portion of said phase pulse being overlapped to said leading edge portion of next said phase pulse for transferring an ON state of said light-emitting elements; and

two controllable current sources connected to said first and second longitudinal clock lines, respectively and controlled synchronously with said phase pulses for supplying an additional current to said ON state light-emitting element.

13. A self-scanning light-emitting element array comprising:

an array on pnpn laser thyristors disposed with a predetermined pitch along a longitudinal direction and separated by crosswise grooves provided on a pnpn structure, integral to a common cathode layer and each having a crosswise anode and a crosswise gate for controlling its turn-on threshold;

a first insulating film covering the entire upper surface of the grooved structure;

a two-dimensional resistive film provided on said first insulating film, connected to said gates of said laser thyristors through equidistant upper contact holes provided in said first insulating film to provide a plurality of coupling means.

a second insulating film covering the whole upper surface of said first insulating film;

a bias line provided on lower side of said resistive film through a longitudinal contact hole to provide a plurality of pull-up means; and

first, second and third longitudinal clock lines provided on said second insulating film above said laser thyristors, each connected through other contact holes provided in said first and second insulating films to said anodes of said first, second and third groups of said laser thyristors in every third fashion.

14. A self-scanning light-emitting element array comprising:

an array on pnpn laser thyristors disposed in a line with a predetermined pitch along a longitudinal direction and separated by crosswise grooves provided on a pnpn structure, integral to a common cathode layer and a notched lower gate layer and each having a crosswise anode, said notched lower gate layer having a plurality of narrow portions equivalent to coupling means between gates thereof;

an insulating film covering the entire upper surface of the grooved structure; and

first, second and third longitudinal clock lines provided on said insulating film above said laser thyristors, each connected through other contact holes provided in said insulating film to said anodes of said first, second and third groups of said laser thyristors in every third fashion.

15. A self-scanning light-emitting element array comprising:

an array of pnpn laser thyristors disposed in a line with a predetermined pitch along a longitudinal direction and separated by crosswise grooves provided on a pnpn structure, integral to a common cathode layer, and each having a central crosswise anode and a right-side gate;

an insulating film covering the entire upper surface of the grooved structure;

a plurality of uni-directional coupling means provided on left-side portions of said laser thyristors partitioned by second grooves, respectively;

a plurality of electrodes provided on said insulating film and each connecting one of said uni-directional coupling means with the next gate of said laser thyristor through a contact hole provided in said insulating film; and

first and second longitudinal lines provided on said insulating film, each connected through another contact hole provided in said insulating film to said anodes of said every other light-emitting elements.