Microinjector head having driver circuitry thereon and...

Details Microinjector head having driver circuitry thereon and... Microinjector head having driver circuitry thereon and...

2002-01-03

2002-10-29

Hallacher, Craig (Department: 2853)

Incremental printing of symbolic information

Ink jet

Ejector mechanism

C347S065000, C029S890100

Reexamination Certificate

active

06471338

ABSTRACT:

BACKGROUND OF INVENTION
1. Field of the Invention
The invention relates to a microinjector head and its manufacturing method, and more particularly, to a microinjector head with a driving circuitry and the manufacturing method of the microinjector head.
2. Description of the Prior Art
At present, droplet injectors are widely applied in inkjet printers. Droplet injectors also have many other applications in different fields such as fuel injection systems, cell sorting, drug delivery systems, direct print lithography and micro jet propulsion systems. The common aim of the above applications is to provide a droplet injector that is reliable, of low-cost, and provides high-quality droplets with a high frequency and a high spatial resolution.
However not all apparatuses can successfully inject uniform droplets. In currently known and used droplet injection systems, one system using thermally driven bubbles to inject droplets is proved to be a successful system because of its comparatively simple architecture and lower cost.
U.S. Pat. No. 6,102,530-“Apparatus and method for using bubbles as virtual valve in microinjector to eject fluid” mentions a droplet injection apparatus with virtual valves as shown in FIG.
1
. Heaters
20
,
22
are located around orifices
18
. A first bubble is generated between a manifold
16
and a fluid chamber
14
. Therefore the first bubble acts like a virtual valve and is capable of reducing a cross talk effect with the adjacent chambers. A second bubble is then generated and approaches the first bubble to push the fluid, causing a droplet to be ejected from the orifice
18
. Finally, the second bubble fuses with the first bubble and successfully reduces the production of satellite droplets.
U.S. Pat. No. 5,122,812-“Thermal inkjet print head having driver circuitry thereon and method for making the same” mentions a structure of an inkjet print head with driving circuitry as shown in FIG.
2
. Heating devices and driving circuitry are integrated on a same substrate. However there are still many steps in the process. And according to the structure, a barrier layer
130
of 20~30 &mgr;m in thickness must be formed and an orifice plate is adhered on the barrier layer
130
. This adhesion procedure limits the spatial resolution due to unavoidable assembly tolerance. In addition, the adhesion procedure is not compatible with general IC processes. When microinjector arrays are integrated with driving circuitry to reduce layout and are tightly packed, such incompatibility problems become more obvious and lead to more complicated manufacturing processes and thus higher costs.
SUMMARY OF INVENTION
It is therefore a primary objective of the claimed invention to provide a microinjector head with driving circuitry to control a plurality of first and second bubble-generating devices to eject fluid in a plurality of chambers from orifices. A secondary objective of the claimed invention is to provide a manufacturing method for making a microinjector head with driving circuitry in fewer steps and with fewer number of circuit devices and linking circuits.
According to the claimed invention, the microinjector head with driving circuitry to eject fluid uses a bubble as a virtual valve. The microinjector head comprises a plurality of chambers, a manifold connected to the chambers for providing fluid to the chambers, a plurality of orifices open to corresponding chambers, a plurality of pairs of bubble generators, each pair of bubble generators comprising a first and a second bubble-generating devices near a corresponding orifice and above the corresponding chamber, the first bubble-generating device generating a first bubble that is used as a virtual valve, the second bubble-generating device generating a second bubble to cause liquid in the chamber to eject from the orifice when the chamber is filled with fluid, and a driving circuit comprising a plurality of functional devices disposed on a same substrate. The driving circuit can send a driving signal to a specific pair of bubble generators so as to eject droplets out of the corresponding orifices. The first bubble generator and the second bubble generator may be two resistive heaters with different resistances and may be connected to each other in series.
It is an advantage of the claimed invention that the microinjector head and the manufacturing method provide a micro droplet injector head manufactured with lower cost and fewer procedures.
These and other objects and the advantages of the present invention will no doubt become obvious to those of ordinary skill in the art after having read the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings.


REFERENCES:
patent: 4695853 (1987-09-01), Hackleman et al.
patent: 4947192 (1990-08-01), Hawkins et al.
patent: 5122812 (1992-06-01), Hess et al.
patent: 5216447 (1993-06-01), Fujita et al.
patent: 5726697 (1998-03-01), Shimoda
patent: 6102530 (2000-08-01), Kim et al.
patent: 0317171 (1989-05-01), None
patent: 0493897 (1992-07-01), None

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