Printed led driver circuit

Patent metadata

Field	Value
Publication number	US-2016238201-A1
Application number	US-201615009727-A
Country	US
Kind code	A1
Filing date	Jan 28, 2016
Priority date	Feb 16, 2015
Publication date	Aug 18, 2016
Grant date	—

Abstract

On a flexible substrate is printed LEDs and a driver circuit containing transistors. The LEDs and transistors are printed microscopic devices contained in an ink. The LEDs are printed in groups and connected in parallel, and the transistors are printed in groups and connected in parallel. Other components, such as resistors and an on/off switch, are also printed to form the driver. A battery and other circuit components may also be printed on the substrate. An overlay is provided over the LEDs to create a desired light pattern. The LEDs and driver may be generic, and the overlay customizes the light pattern for a particular application. The transistors in the driver may be interconnected with a trace pattern to drive the LEDs in a customized manner, such as for an insert in a product package for marketing to a consumer.

First claim

What is claimed is:

1 . A structure including a circuit, the structure comprising:
a flexible substrate; light emitting diodes (LEDs) printed over the substrate, the LEDs being printed as one or more groups of LEDs, wherein multiple LEDs in each group are connected in parallel, and wherein the LEDs are randomly distributed within each group on the substrate; a driver, comprising transistors, for the LEDs printed over the substrate, the transistors being printed as one or more groups of transistors, where multiple transistors in each group of transistors are connected in parallel, and wherein the transistors are randomly distributed within each group of transistors on the substrate; and an interconnection conductor pattern on the substrate that interconnects the one or more groups of LEDs to the driver to energize the one or more groups of LEDs.

2 . The structure of claim 1 wherein the driver comprises groups of MOSFETs that are interconnected by the conductor pattern to drive the one or more groups of LEDs.

3 . The structure of claim 1 wherein the driver comprises groups of bipolar transistors that are interconnected by the conductor pattern to drive the one or more groups of LEDs.

4 . The structure of claim 1 wherein the printed LEDs and printed transistors have a largest dimension less than 200 microns.

5 . The structure of claim 1 wherein each group of LEDs contains substantially identical LEDs, and each group of transistors contains substantially identical transistors.

6 . The structure of claim 1 further comprising a printed battery over the substrate and connected to the driver circuit via the conductor pattern.

7 . The structure of claim 1 wherein each of the transistors has three terminals comprising a first electrode, a second electrode, and a third electrode, wherein the first electrode is a bottom electrode of the transistors, the third electrode is a top electrode of the transistors, and the second electrode is an intermediate electrode located vertically between the top electrode and the bottom electrode, the circuit further comprising:
a first conductor layer over the substrate, wherein the first electrode of the devices is electrically connected to the first conductor layer;
a first dielectric layer overlying the first conductor layer;
a second conductor layer overlying the first dielectric layer to electrically contact the second electrode; and
a second dielectric layer over the second conductor layer; and
a third conductor layer overlying the second dielectric layer to electrically contact the third electrode,
wherein the transistors are electrically connected in parallel by a combination of the first conductor layer, the second conductor layer, and the third conductor layer.

8 . The structure of claim 7 wherein the transistors are formed to have a lower portion that is wider than an upper portion of the devices, the lower portion forming a shelf, wherein the second electrode is formed on the shelf.

9 . The structure of claim 7 wherein the second electrode is offset from a midway point on the transistors between the first electrode and the third electrode.

10 . The structure of claim 7 wherein electrical signals are coupled to the first conductor layer, the second conductor layer, and the third conductor layer to operate the transistors in parallel.

11 . The structure of claim 1 wherein the substrate has a patch area, wherein each group of transistors has at least one electrical connector that extends from its associated group and terminates in the patch area, and wherein the interconnection conductor pattern comprises conductors that electrically connect to the groups at the patch area.

12 . The structure of claim 1 wherein the groups of transistors are deposited in a 2-dimensional array.

13 . The structure of claim 1 wherein the driver further comprises printed resistors connected to the groups of transistors via the conductor pattern.

14 . The structure of claim 1 further a light passing layer overlying the one or more groups of LEDs, the light passing layer blocking some of the light emitted by the one or more groups of LEDs and passing some of the light to create a pattern of light.

15 . The structure of claim 14 wherein the light passing layer comprises an opaque sheet with areas cut out in a pattern.

16 . The structure of claim 14 wherein the light passing layer includes graphics.

17 . A method for forming a structure including a circuit, the method comprising:
providing a flexible substrate; printing pre-formed inorganic light emitting diodes (LEDs) over the substrate, the LEDs being printed as one or more groups of LEDs, wherein multiple LEDs in each group are connected in parallel, and wherein the LEDs are randomly distributed within each group on the substrate; printing a driver, comprising transistors, for the LEDs over the substrate, the transistors being printed as one or more groups of transistors, where multiple transistors in each group of transistors are connected in parallel, and wherein the transistors are randomly distributed within each group of transistors on the substrate; and forming an interconnection conductor pattern on the substrate that interconnects the one or more groups of LEDs to the driver to energize the one or more groups of LEDs.

18 . The method of claim 17 wherein the driver comprises groups of MOSFETs or bipolar transistors that are interconnected by the conductor pattern to drive the one or more groups of LEDs.

19 . The method of claim 1 further comprising positioning a light passing layer over the one or more groups of LEDs, the light passing layer blocking some of the light emitted by the one or more groups of LEDs and passing some of the light to create a pattern of light.

20 . The method of claim 1 wherein the LEDs and transistors have a largest dimension less than 200 microns.

Assignees

• Nthdegree Tech Worldwide Inc

Inventors

• Ray Alexander
• Blanchard Richard
• Barber Shawn
• Moffenbeier David

Classifications

• H05K2201/10106

  Light emitting diode [LED] · CPC title

• H05K2201/10037

  Printed or non-printed battery · CPC title

• B65D2203/12

  Audible, olfactory or visual signalling means (B65D51/248, B65D55/028, B65D79/02 and B65D81/24 take precedence) · CPC title

• B65D5/4212

  Information or decoration elements, e.g. content indicators, or for mailing (B65D5/522 takes precedence) · CPC title

• B65D5/4216

  Cards, coupons or the like formed integrally with, or printed directly on, the container or lid · CPC title