DE10007052A1 - Production of components of a drop generator comprises etching peripheral slits in a first wafer to form frame plates, etching nozzles having pre-chambers in a second wafer - Google Patents

Abstract

Production of components of a drop generator comprises: (i) etching peripheral slits in a first wafer to form frame plates (5) on three sides and an open liquid longitudinal channel on one side surface; (ii) etching nozzles (3) having pre-chambers (3c) in a second wafer; (iii) connecting the wafers by bonding to the side surfaces; and (iv) cutting out a number of bending converters from the bonded wafers as base plate.

Description

The invention relates to a method for producing components of a dropper Producer for microdrops, especially a nozzle head for ink printers, with in a housing arranged, multilayer, piezoelectric bending transducer, the has a bending comb, the rear region of which is a passive section of the Comb teeth through a connecting dam and its front, the nozzles ordered area that forms the active section consisting of bending tongues.

Such a bending transducer is known from DE 691 20 806 T2. Here is the trop The generator is relatively complex and places very high demands on the Production and assembly of the individual parts. Part tolerances and assembly tolerances lead to differences in drop size, ejection angle and frequency of the individual pairings so that the printouts (dot patterns) that can be achieved with them are uneven because the position of the drops is undefined. Thereby falsification of information can occur. The assembly provides precise position highest requirements in the 1 µm range. Prerequisite for a corresponding high-precision assembly is the high-precision manufacture of the individual parts.

The invention has for its object, by simpler and therefore high quality Manufacturing a reduced number of individual parts to make the assembly more precise ten.

According to the invention, the object is achieved on the basis of a first alternative solved that in a first wafer to produce frame plates on three Side circumferential slots for the active section of the comb teeth and on one side surface of an open longitudinal channel that can be etched into a second Wafers to produce base plates, nozzles with nozzle antechambers and bonding the first wafer and the second wafer together on the side surface which are connected and that a variety of bending transducers as a base plate cut out of the bonded wafers. This manufacturing process is simplified not only the individual parts, but also contributes to the maintenance of extremely low manufacturing toles satchel at. The manufacturing tolerances are only due to the resolution accuracy the manufacturing process (e.g. photolithography). By etching the frames plate in the wafer the highest accuracy is achieved. So not only the fluidlen kung, d. H. the liquid longitudinal channel, but at the same time etched the bending tongue. It therefore combines a minimal manufacturing time with minimal manufacturing tolerances.

The entire wafer can be bonded. The bonding places on the contact surface such a connection that a monolithic body is formed, so that Frame walls, the passive section and the top layer in the area of the nozzles without Glue get along and no glue overhangs can arise.

The object is also achieved according to the invention based on a second alternative solved in that in a first wafer for the production of frame plates circumferential slots on three sides for the active section of the comb teeth and one lower longitudinal fluid channel in the direction of the comb teeth and one nozzle each be etched that a second wafer is pre-created for the production of flat base plates and will see that the first and second wafers are bonded to the side of the Longitudinal liquid channel are connected to each other and that a variety of such lined-up bending transducers as the base plate from the bonded  Wafers are cut out. This also creates the first ones Alternatives described advantages.

It is also alternatively advantageous that the nozzle is either in the frame plate in the direction of the longitudinal liquid channel or in the base plate in the direction of the river longitudinal channel are etched. In the first case, only one wafer has to be etched at all, while the other can be used as is commercially available.

A third alternative for the manufacture of the nozzle is that the nozzle is in the flat base plate is etched perpendicular to the base plate level. This allows the Drop ejection takes place in a different direction depending on the installation of the bending transducer Find.

Another step in the production is given by the fact that the first wafer and the second wafer anodically or by the direct silicon fusion process the. This enables the wafers with their unchanged surfaces without Connect additives.

According to further features, there can be a gap of around 2-10 µm around the bending tongue are etched, with the recesses for the active Ab in the frame plate cut the bending comb taking into account the rear passive section be etched. An exact length of the bearing and the space for bending ge is achieved by a graded etching from the area of the passive section. A frame wall to the adjacent duct remains between the units received so that crosstalk problems between two bending tongues do not may occur. This structure can be achieved with the available silicon Etching techniques such. B. reactive ion etching or the known advanced silicone Etching, safe and precise manufacture. This enables structure depths of 250-300 µm and  Aspect ratios of 1:75 can be realized. The number of nozzle channels is in one Integrated photo mask. When changing the number of nozzles only the photo mask is required to be changed. Silicon is suitable as a material without residual stress The modulus of elasticity is 130-188 Gpa. All of these properties are expressed here uses.

The recesses can be designed in such a way that in the recesses elongated protrusions are etched for the active section of the bending comb. This will stop the supply of liquid (such as oil or water based ink) reinforced.

All steps can be carried out on suitable materials. Advantageously the first wafer and the second wafer are made of either silicon or glass to get voted.

According to further features, it is proposed that the respective active Ab cut the bending comb a piezo actuator with a monomorphic or bimorph structure is stuck on. This results in further advantages: the silicon bending tongue (elec tric non-conductive) and the piezomaterial can be of different sizes limit, whereby the degree of positioning accuracy may decrease. An accuracy between 1-10 µm is sufficient. A return of the Piezowerk Stoffs represents a mass reduction and means a possible frequency increase tion.

The droplet generator for microdrops, especially as a nozzle head for ink printers (Device), is arranged in a housing, has a multilayer, piezo electric bending transducer on with a bending comb, the rear area a passive section of the comb teeth through a transverse connection dam and its front area, assigned to the nozzles, the active one, made of bending form the existing section.  

The task of creating a simple and more precisely manufactured bending transducer is solved according to the invention in that a base plate consisting of a Base plate with a bonded frame plate and with on the bending tongues each glued-on piezo actuator is provided, being in the base plate or in the In the front area of the frame plate, a nozzle channel is etched with a elongated liquid longitudinal channel, which is inserted at the bottom of the frame plate is working, communicating. As a result, the bending tongues are located immediately etched together with the longitudinal liquid channel in the frame plate and the Nozzles (possibly with nozzle antechambers) in the base plate, which with high accuracy in the two wafers can be produced and only after joining the Wafers are cut out, creating finished base plates for a bending transducer arise. The accuracy of the location of the individual surfaces, walls and floors is therefore extremely high.

Another special feature is that in the base plate in the front A nozzle prechamber is connected to the nozzle channel in the area is. This improves the inflow of the liquid (e.g. the ink).

According to other features, is applied by means of the respectively on the bending tongue Piezo actuator a biasing force can be transferred to the bending tongue. When energized The preload force is generated and the spring force is released when switching off ben that ejects the ink drop.

Another embodiment is that the piezo actuator on the bending tongue forms a shoulder to the frame plate and that within the heel area by the End of the bending tongue connects to the liquid longitudinal channel in the frame plate is formed. This results in a reduction in mass with the same pressure ratio nissen achieved.  

Finished base plates are prepared in the wafers bonded to one another such that the bending transducers from the wafers by separating cuts along the outline are detachable.

Another feature is used to prepare electrical connections and provides that a field without metal is formed in the rear area.

It is also proposed that the field without metal in the rear area is electrically separated from a common electrical connection plate.

Other characteristics serve the dynamics of movements. It is envisaged that the Bending tongue between a rear area and a front area has a narrower basic shape deviating from the parallel slot course.

This idea is further developed in such a way that the bending tongue in the front Area a consistently wide longitudinal section, then one laterally receding longitudinal section and following this grow a conical forms the longitudinal section.

Another improvement is that at the end of the flex tongue Tappet is formed, the be on the axis of the nozzle due to the piezo force is removable.

In the drawing, embodiments of the invention are shown, the following are explained in more detail.

Show it:

Fig. 1 is a vertical cross section of the bending transducer (without housings) as a first alternative,

Fig. 2 that belongs to Fig. 1, top view,

Fig plate. 3 is a vertical cross section through the separately drawn frame,

Fig. 4 belonging to FIG. 3 top view,

Fig. 5 is a separate perspective view of the piezoelectric actuator,

Fig. 6 is a vertical cross section of the bending transducer as the second alternative,

Fig. 7 shows a detail A of Fig. 6 in an enlarged scale,

Fig. 8 shows a detail of FIGS. 6 and 7 in a perspective view and

Fig. 9 is a vertical cross section through the bending transducer as a third alternative embodiment.

The bending transducer 1 is arranged in a housing (not shown in more detail) and has a bending comb 2 . The rear region 2 a forms a passive section from the comb teeth 2 c under a transverse connecting dam, which can be designed as a connecting bar and connects the comb teeth 2 c. The vorde re area 2 b, the active area, is assigned to the nozzles 3 and consists of active bending tongues 4 , which are driven piezo-electrically.

Referring to FIG. 1, a base plate 8 of a base plate 6 and a frame plate 5 is assembled. The bending tongues 4 carry a piezo actuator 7 connected by adhesive, which is provided for each bending tongue 4 and the power connection assigned to it. In the base plate 6 , upper nozzle channels 3 a and lower nozzle channels 3 b are etched in the front area 2 b, so that the frame plate 5 can also be arranged on the underside 5 d, ie several such bending transducers 1 can be attached to one another or to one another. The nozzles 3 are then etched as drawn as the upper nozzle duct 3 a and the lower nozzle duct 3 b. The respective nozzle channel 3 a, 3 b is in communication with the elongated longitudinal liquid channel 9 through a nozzle antechamber 3 c. The longitudinal liquid channel 9 simultaneously causes the formation of the bending tongue 4 and is therefore matched in its length to the front region 2 b of the bending tongue 4 , the rear region 2 a acting as a bending bearing and merging into the connecting dam of the bending comb 2 .

The piezo actuator 7 on the bending tongue 4 forms a shoulder 11 to the frame plate 5 with a shoulder surface 11 a, so that a connection 12 to the liquid channel 9 is formed, with a sufficient fluid supply under the bending tongue 4 together with d from bores 5 c is created.

FIG. 2 shows that the bending transducers 1 are formed in the wafers by slots 5 a or etches 5 b, so that bending tongues 4 can be formed in the wafers by slots 5 a and / or etches 5 b. The outline 22 represents the outer shape of the bending transducer 1 , along which the separation from the wafer takes place by sawing. Finished bending transducers 1 are separated from a bonded composite wafer by sawing along the outer shape, ie in the outline 22 ; the nozzles 3 are opened.

A field without a metal layer is formed in the rear region 2 a. This field is electrically separated from a common connection plate 13 (see FIG. 5). The slots 5 a or etches 5 b are provided with bulges 5 c in a medium length range, the course of the slots being included in the bulges.

FIGS. 3 and 4 show the frame plate 5 as a separate item, so that there the manufacturing steps are easily recognizable. The end 4 d of the bending tongue 4 defines together with the connection 12 the bending length of the bending tongue 4 . The etching 5 b and the formation of the bearing in the rear region 2 a can be seen there.

Technically, the connection 12 consists of a slot 5 a ( FIG. 4) at the end 4 d of the bending tongue 4 in the front region 2 b. In the rear area 2 a, the bending tongue 4 is practically held by the comb teeth 2 c. The outer contour of the bending tongue 4 (and also the piezo actuator 7 ) can vary. The bending tongue 4 is shaped between the rear region 2 a and the front region 2 b with a narrow basic shape 21 deviating from the parallel slot 10 . The bending tongue 4 forms in the front region 2 b only a constant wide longitudinal section 4 a, followed by a laterally withdrawing longitudinal section 4 b and following this a conically growing longitudinal section 4 c.

At the end 4 d of the bending tongue 4 , a plunger (not shown) can be formed, which can be moved back and forth approximately on the axis of the nozzle 3 due to the generated piezo force.

According to Fig. 5 adjacent to the electrical terminal plate 13, the piezo-actuators 7 are visible on the tongues 4 bending. A preformed piezo actuator element with individual actuator fingers 7 a, which are each attached to a bending tongue 4 by gluing, is shown in the figure.

In Figs. 6 and 7, a second alternative of the bending transducer 1 is shown: In contrast to the first alternative (Fig. 1 to 4), the base plate is etched b completely smooth and flat and without the nozzle channels 3 a or 3 6. For this purpose, the nozzle is in alignment with the longitudinal liquid channel 9 in the frame plate 5 . The frame plate 5 remains unchanged in the rear region 2 a as a bearing on the base plate 6 and is produced according to the method. The piezo actuator 7 is also arranged and fastened on each bending tongue 4 as described. The bending tongue 4 swings back and forth in the liquid inlet 15 in accordance with the piezo force at the drop outlet 14 , so that the smallest drops of liquid 18 are expelled on the end face 17 with each energizing pulse.

According to Fig. 8 liquid column 16 are laterally adjacent to the bending tongues 4 are each formed, the plate between the flexible tongue 4 and the frame 5 are formed corresponding to the etched.

A third alternative is visible in Fig. 9: In the frame plate 5 , which is tightly connected to the base plate 6 , in turn, the liquid longitudinal channel 9 is formed. The nozzle 3 is arranged in the base plate 6 , on its side surface 19 , perpendicular to the base plate plane 20 , so that the drop 18 is expelled in the direction of the arrow given by the axis of the nozzle 3 in the movement curve 4 e.

The manufacturing process is carried out as follows:

In a first wafer for the generation of frame plates 5 are respectively applied to three sides of slots 5 a with bulges 5 c to the rear portion 2 a performed by etching (Fig. 2). The longitudinal liquid channel 9 and the connection 12 are then etched into the frame plate 5 . When using the second alternative, the nozzle 3 is also etched in alignment with the longitudinal liquid channel 9 .

After the upper nozzle channel 3 a and the lower nozzle channel 3 b have also been etched into the base plate 6 and also the nozzle antechamber 3 c, the first wafer and the second wafer can be bonded with the surfaces to be placed against one another. The piezo actuators 7 , which are connected by the bending comb 2, are then glued onto the bending tongues 4 which are already present. However, the gluing can also take place at a different time, so that the sequence of the steps changes.

After bonding, the plurality of bending transducers 1 existing on the combination wafer is cut out.

Reference list

1

Bending transducer

2

Bending comb

2

a rear area

2

b front area

2

c comb teeth

3rd

Nozzles

3rd

a upper nozzle channels

3rd

b lower nozzle channels

3rd

c Nozzle pre-chamber

4

Bending tongue

4

a longitudinal section

4

b receding longitudinal section

4

c conical longitudinal section

4

d end

4

e movement curve

5

Frame plate

5

a slot

5

b etching

5

c bulge

5

d bottom

6

Base plate

7

Piezo actuator

7

a Actuator finger

8th

Base plate

9

Longitudinal liquid channel

10th

Slot course

11

paragraph

11

a sales area

12th

connection

13

electrical connection plate

13

a single electrode

13

b Field without a metal layer

14

Drop leakage

15

Fluid supply

16

Liquid gap

17th

Face

18th

(Ink) drops

19th

Side surface

20th

Base plate level

21

Basic form

22

outline

Claims (19)

1. A method for producing components of a droplet generator for microdrops, in particular a nozzle head for ink printers, with a multilayer, piezoelectric bending transducer arranged in a housing, which has a bending comb, the rear area of which is a passive section of the comb teeth through a connecting dam and its front Be the area assigned to the nozzles, the active section consisting of bending tongues, characterized in that in a first wafer for producing frame plates teeth on three sides circumferential slots for the active section of the comb and etched on one side surface an open longitudinal liquid channel be that in a second wafer for the production of base plates, nozzles with nozzle antechambers are etched and the first wafer and the second wafer are connected to one another by bonding on the side face and that a multiplicity of bending transducers as the base plate from the bonded wafer be cut out remotely. 2. Method for producing components of a droplet generator for microdrops, in particular a nozzle head for ink printers, with a multilayer, piezoelectric bending transducer arranged in a housing, which has a bending comb, the rear area of which is a passive section of the comb teeth through a connecting dam and its front , the area assigned to the nozzles, forms the active section consisting of bending tongues, characterized in that
that in a first wafer for the production of frame plates on three sides circumferential slots for the active section of the comb teeth as well as in each case a lower longitudinal liquid channel in the direction of the comb teeth and in each case a nozzle are etched, that a second wafer is provided for producing flat base plates and
that the first and second wafers are bonded to one another by bonding on the side of the liquid longitudinal channel and that a multiplicity of such bending transducers lined up as a base plate are cut out of the bonded wafers. 3. The method according to any one of claims 1 or 2, characterized, that the nozzle is either in the frame plate towards the liquid longitudinal channel or in the base plate in the direction of the liquid longitudinal channel are etched. 4. The method according to claim 2, characterized, that the nozzle in the flat base plate perpendicular to the base plate Level is etched.   5. The method according to claim 1 or 2, characterized, that the first wafer and the second wafer anodically or after the Di rect-silicone fusion processes are bonded. 6. The method according to any one of claims 1 to 5 characterized, that in the frame plate the recesses for the active section of the bending comb taking into account the rear passive Section can be introduced by slitting or etching. 7. The method according to claim 6, characterized, that into the recesses for the active section of the bending comb elongated protrusions are etched. 8. The method according to any one of claims 1 to 7, characterized, that the first wafer and the second wafer are either silicon or can be chosen from glass. 9. The method according to any one of claims 1 to 8, characterized, that a piezo on the respective active section of the bending comb Actuator with monomorphic or bimorphic structure is glued on.   10. droplet generator for microdroplets, in particular nozzle head for ink printer, which has a multi-layer, piezoelectric bending transducer arranged in a housing, which has a bending comb, the rear area of which is a passive section of the comb teeth through a transverse connecting dam and its front, assigned to the nozzles Area forms the active section consisting of bending tongues, characterized in that a base plate ( 8 ) consisting of a base plate ( 6 ) with a bonded-on frame plate ( 5 ) and with piezo actuators ( 7 ) glued onto the bending tongues ( 4 ) ) is provided, wherein in the base plate ( 6 ) or in the frame plate ( 5 ) in the front region ( 2 b) each has a nozzle channel ( 3 a; 3 b) etched with an elongated liquid longitudinal channel ( 9 ), the on the underside ( 5 d) of the frame plate ( 5 ) is incorporated, is connected. 11. Drop generator according to claim 10, characterized in that in the base plate ( 6 ) in the front region ( 2 b) arranged nozzles ( 3 ) to the nozzle channel ( 3 a; 3 b), a nozzle antechamber ( 3 c) is closed. 12. Drop generator according to claim 10 or 11, characterized in that by means of the bending on the tongue (4) are each applied piezo actuator (7) each have a biasing force on the flexible tongue (4) is the carry bar. 13. drop generator according to one of claims 10 to 12, characterized in that the piezo actuator ( 7 ) on the bending tongue ( 4 ) forms a shoulder ( 11 ) to the frame plate ( 5 ) and that within the heel surface ( 11 a) by End ( 4 d) of the bending tongue ( 4 ) a connection ( 12 ) to the liquid longitudinal channel ( 9 ) is formed in the frame plate ( 5 ). 14. Drop generator according to one of claims 10 to 13, characterized in that the bending transducers ( 1 ) can be separated from the wafers by separating cuts along the outline ( 22 ). 15. Drop generator according to one of claims 10 to 14, characterized in that a field without metal in the rear region ( 2 a) is formed. 16. Drop generator according to claim 15, characterized in that the field without metal in the rear region ( 2 a) is electrically separated from a common electrical connection plate ( 13 ). 17. Drop generator according to one of claims 10 to 16, characterized in that the bending tongue ( 4 ) between a rear area ( 2 a) and a front area ( 2 b) deviates from the parallel slot profile ( 10 ), narrower basic shape ( 21 ) having. 18 drop generator according to claim 17, characterized in that the bending tongue ( 4 ) in the front region ( 2 b) a constant wide longitudinal section ( 4 a), then a laterally receding longitudinal section ( 4 b) and following this a conically growing Longitudinal section ( 4 c) forms. 19. Drop generator according to one of claims 10 to 18, characterized in that a plunger is formed on the end ( 4 d) of the bending tongue ( 4 ), which on and about the axis of the nozzle ( 3 ) due to the generated piezo force is movable here.