JPH0157769B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention particularly relates to a structure for passing through a glass wall or a quartz glass wall, such as a Kelcell electrical connection conductor.

A high degree of precision is required when manufacturing digital optical deflectors formed by Kelcell.
The manufacturing method is complicated and expensive.

Most optical deflectors are made using quartz fusion technology. However, since assembly requires a temperature of approximately 1000°C, it has been difficult to maintain manufacturing deviation within the μm range. Moreover, the defective rate during manufacturing is extremely high. Due to their sensitivity to impact and the residual tensile stress within the glass, the cells of the product may not exhibit the required life of at least two years.

For example, German patent No. 964152 describes ceramics,
A metal penetration part in the form of a bolt or pipe is installed in a container or wall of an insulating material such as glass or synthetic resin in an airtight and watertight manner, and the penetration part in the metal container or wall is directly buried in the target material. It is stated that insulation must be maintained. German Patent No. 964152 thus describes a method using a metal wall with oil-tight, gas-tight and electrically insulated lead-throughs. However, in contrast to this method, insulation is not a problem in the through-holes that are the object of the present invention. On the other hand, the present invention has the above-mentioned difficulties in terms of quartz glass melting technology.

German Patent No. 964152 describes the use of a metal through-bolt to firmly connect it to a central retaining member of insulating material. This center holding member is
It has sharp protrusions. The center retaining member is disposed such that its protrusion enters a corresponding diametrical hole in the metal wall. Furthermore, in this case, cup-shaped molds are attached to both sides of the metal wall. These molds and the spaces inside the molds are filled with a molding resin that does not emit volatile components and does not become soft again after hardening. Although this method can solve the insulation problem as described above, it cannot be used in the method to which the present invention is directed. This is because a requirement of the object of the present invention is that the completed penetration does not protrude beyond the wall. The drawbacks of this protrusion will be explained in detail below.

German Patent Publication No. 1045499 describes an electrically insulating component formed by several layers, which is used, for example, to insulate conductors from a housing. This insulating member consists of a layer of molding resin containing a filler, and the type or amount of the filler is made different for each layer. Furthermore, German Patent Publication No. 1 267 737 discloses that electrical devices, such as transformers and coils, can be impregnated in a mold or housing with a non-volatile molding resin in a single step, and further embedded therein. , it is also described that the space between the electrical device and the windings or the space between the walls of the housing or the walls of the mold is filled with a filler, which is then filled with pure molding resin. In these two known examples, insulation problems arise.

German Patent Publication No. 2 356 237 describes the production of vacuum-tight glass joints using a cyanoacrylate and talcum paste for use in areas that come into contact with aggressive liquids, and in particular for digital light applications. It has been described that the deflector has a housing made of quartz glass and filled with an aggressive liquid such as nitrobenzene. However, such glued connections cannot be compared with the penetration elements that are the object of the present invention. This is because the thicknesses of these two materials are extremely different by several times. Research into the present invention has shown that this adhesive technique cannot be used for the penetrations of Kelcell electrical connections. This is because cyanoacrylate talcum cement provides very little stiffness and cannot withstand the desired mechanical loads. Furthermore, there is no need to apply the above-described penetrating member forming technique to the Kelcell of the present invention. This is because insulation of the penetrating member is not a problem in Kelcell.

An object of the present invention is to obtain a mechanically strong, dimensionally accurate, and vacuum-tight electrical lead-through without using quartz glass melting technology.

According to the invention, this through-conductor portion is provided with a polytetrafluoroethylene ring that secures the conductor in the lower part of the aperture through the wall facing the interior of the cell so that the conductor is held in the center of the aperture. A layer of cyanoacrylate talcum cement is provided above the ring in this open hole, and a layer of granular filler soaked in cyanoacrylate adhesive is provided above the layer in the single-sided obstructed hole thus formed. ,
Then, a layer of cyanoacrylate talcum cement is filled and sealed at the top facing the outside of the cell.
It is characterized in that the layer 6 of granular filler ensures mechanical support for the through conductor 1.

In the present invention, the layer of particulate filler soaked in cyanoacrylate adhesive can be composed of several sublayers.

An advantage of the invention is that the mechanical strength of the penetration is much greater and more stable than in the case of a Kelcell housing made of glass parts, which can be demonstrated, for example, by a forced tensile test.

The above-described through conductor portion formed according to the present invention does not protrude from the wall portion. This is because the adhesive plug formed by the cyanoacrylate-containing layer is protected by the polytetrafluoroethylene layer against aggressive liquids within the cell.

The present invention will be explained below with reference to the drawings.

In FIG. 1, an electrode 2 is supported by an electrically conductive pin 1, such as a tungsten pin. This tungsten pin 1 is inserted through an opening provided in a quartz glass wall 3. This hole is filled with the following layers from the bottom to the top.

●An annular disc 4 of polytetrafluoroethylene.

●Layer 5 of cyanoacrylate talcum cement.

● Several layers 6 of granular filler soaked in cyanoacrylate adhesive.

●Layer 7 of cyanoacrylate talcum cement.

A disc of polytetrafluoroethylene (PTFE) was chosen for the bottom layer 4, since this material is completely resistant to attack by nitrobenzene. This holds electrical conductors, such as tungsten pins, in place and acts as a screen for adhesive cement. However, this disc is not a 100% complete seal, and it is sufficient to prevent uncured adhesive from leaking beyond it.

The upper layer 5 of cyanoacrylate talcum cement acts as a nitrobenzene-tight barrier for the lead-through conductor. Pure cyanoacrylate monomer does not become hard like cement, so fillers are added. For example, a monomer with a viscosity of 120 cP/25° C. is used, together with a filler and a small liquid mixture, which in the cured state exhibits the most advantageous flexible hardness. If you line up
The same hardness can be obtained using other commercially available monomers, such as 1500 cP/25°C viscosity, but this is not suitable for that use.

Talcum (talcum, talc) was selected as the filler because of its flexibility, adhesiveness, hardenability and coexistence bonding properties, and because it exhibits these properties advantageously. 3 to 3 at 40% relative humidity using a mixture of 30% by volume cyanoacrylate monoyers.
An effective pot life of 6 minutes was obtained. This pot life can be shortened by increasing the amount of filler and lengthened by decreasing the amount of filler. Increasing the humidity causes the surface of the mixture to harden more quickly. With other fillers, pot life may be too long or too short, and mechanical disadvantages may result. For example, if a mixture of quartz powder is used, the brittleness will be too high and the shrinkage will be too high.

Fillers that exhibit good properties similar to those of talcum are plastolite, muscovite with powdered quartz,
These are mica, chloride and quartz. However, these fillers shorten pot life too much and do not provide the flexibility of talcum.

The next layer 6 acts like a plug to provide mechanical support for the through conductor and is made of a hard solid and porous material. FIG. 2 is an enlarged view showing the principle of the fine structure. In order to satisfy all the necessary requirements, this layer has particles 8, which are held together by their sharp protrusions, and a very large number of small particles 9 which penetrate the surface of the large particles,
Hold between them where they touch each other. This prevents them from easily moving relative to each other. This serves to compensate for (negate) the adhesive condensation force of the adhesive.

Good results are obtained using mixtures of a large number of particles of various particle sizes.

Examples of compositions that have been tested and found to be good are shown below for each defined through conductor dimension.

An example of this is as follows: Pin diameter of the feed-through conductor...1.2 mm Opening diameter...4 mm Cell wall thickness...6 mm For the desired hardness: Fine grain quartz splinter with a volume ratio of 60% (particle size 0.1 mm), 20% volume ratio plastolite 0.5 (product name); 10% volume ratio plastolite 0 (product name); 10% volume ratio plastolite 00 (product name); “Plastrite” is a West German It is a trademark name of the Naintsch company, and is a general paint,
It is a hard mixed material for varnishes and plastics, and its composition consists of the following three components.

Mica (mica) Chlorite (chlorite: hydrated aluminum/magnesium silicate) Quartz Depending on the mixing situation, there are three types: plastolite 0.5, plastolite 0, and plastolite 00.

This mixture is extremely coarse-grained and easily absorbs liquid adhesive. In order to optimally adsorb the adhesive, a monomer with extremely low viscosity is used, and its strong capillary properties are used to penetrate it to a depth of several millimeters.

First, a ring 4 of polytetrafluoroethylene (PTFE) and a seal 5 of adhesive cement are formed. A mixture of particles is first introduced above the seal of the single-sided obturation hole thus formed. This mixture has the composition described above and is a mixture of quartz and plastolite (trade name).

A very low tack liquid cyanoacrylate adhesive is then injected onto the particle mixture, and the particle mixture is immersed in the adhesive solution. The mixture of particles readily absorbs this adhesive solution by capillary action.

In this example, the holes are filled with the particle mixture to a layer thickness of 4 mm. Thus, when the adhesive solution is added, the upper part of the particle layer becomes occluded before air can escape from the lower part of the particle layer.

In order to avoid this drawback without using the extremely laborious vacuum bonding method, the plug is constructed in three layers, each 1.5 mm high. In this way, air will not be trapped. Each of these steps takes approximately 5 minutes to complete.

For additional protection, a fourth layer 7 of cyanoacrylate talcum cement is provided.

The PTFE disc 4 is used as a center fixing member,
This does not have to be very firmly adhered to the pin member 1 of the feedthrough. This is because the center position of the through-hole conductor is further finely adjusted and the electrode 2 is soldered thereto after its position is determined so as to be axially and rotationally adjustable.

This centering disk 4 is pressed into the hole and is pushed as deep as possible into the hole to form an adhesive plug 6 so that a hole with one end closed is formed. Next, the pin 1 of the through conductor is inserted into the pin 1, and the electrode 2 is fixed by adjusting its distance and rotational position. The PTFE disk centers the pin, but does not mechanically secure it completely, nor does it need to completely stabilize it.

The cyanoacrylate talcum cement forms a vacuum-tight seal, but the thicker plug securely tightens the pin through shrinkage upon drying without imparting mechanical loads.

Cyanoacrylate filled plugs provide mechanical stability, but are not themselves vacuum tight.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view showing an example of a conducting wire penetration part of the present invention, and FIG. 2 is an enlarged view showing the structure of a layer obtained by granular filler soaked in cyanoacrylate. DESCRIPTION OF SYMBOLS 1... Pin, 2... Electrode, 3... Glass wall, 4... Annular disc, 5, 7... Cyanoacrylate talcum cement, 6... Granular filler.

Claims (1)

[Claims] 1. In particular, in electrical connections for Kelcells, in a conductor penetration through a glass wall or a quartz glass wall, the conductor 1 is opened in the lower part of the opening through the wall 3 towards the inside of the cell. The conductor 1 is fixed by a ring 4 of polytetrafluoroethylene so as to be held in the center of the hole, and a layer 5 of cyanoacrylate talcum cement is provided on the upper side of the ring in this aperture. On top of said layer in the one-sided obstructed hole is a layer of granular filler that provides good mechanical retention of said conductor 1 in the hole and easy absorption of liquid adhesive, granular dipped in cyanoacrylate adhesive. A layer 6 of filler material is provided, and a layer 7 of cyanoacrylate talcum cement is filled and sealed at the top facing the outside of the cell, so that the layer 6 of granular filler material provides mechanical support for the feedthrough conductor 1. A conductor penetration part characterized by being designed to secure the conductor. 2. The conductor penetration part according to claim 1, characterized in that the layer 6 of granular filler soaked in cyanoacrylate adhesive is formed by a plurality of sublayers.