CS207427B1 - Method of making the optical mirror members with the metal function surface layer - Google Patents

Description

The present invention relates to a method for manufacturing mirror optics by casting from specially treated filled thermoactive resins.

The prior art process consists in direct grinding and polishing of glass surfaces, which are then provided with a reflective metal layer under vacuum. This method is common, especially in convex mirrors, while in the concave shape, the positive shape method is used for production, i.e. a thick metal layer, for example 1 cm thick, is galvanically applied to a polished glass matrix of the opposite shape. kernel presses. The disadvantages of both production methods are, in particular, the high production costs, since in both methods described each mirror or matrix is ground, polished and metallized individually, and the glass block grinding and polishing technology, especially for special shape mirrors such as parabolic and hyperbolic and lengthy and proportional still increases with increasing requirements for shape accuracy and stability. The disadvantage of individual production is with the positive shape removal method, since the glass core is usually pressed and damaged or destroyed due to the different stresses of the galvanically deposited metal and the glass, so that the cores can no longer be reused.

Another significant disadvantage of the individual method of the prior art production of optical mirrors is the fact that it does not allow the transition to mass production and thus rationalization of production.

These disadvantages are overcome by the present invention, since it makes it possible to produce a series of exactly the same shape copies by means of a single polished and polished glass matrix, which are close to those of individually ground and polished glass mirrors in terms of optical properties and shape accuracy. In addition, used; casting technology allows serial production of mirrors of all kinds and shapes. The process of the invention substantially reduces the cost and labor of optical mirror systems while maintaining high technical parameters, since the glass matrix for the production of tens of pieces can be prepared with great precision and care.

The principle of the process according to the invention consists in applying to the negative matrix a metal textured surface layer on which a thermally active filled resin is deposited under reduced pressure, which is removed from the matrix with the functional layer.

The actual production of mirror optics according to the invention consists of several operations:

1. Production and preparation of glass matrix

(a) grind and polish matrices of a shape opposite to the desired shape of the future optical mirror from the optical-quality glass block. Such a disposable die can withstand tens of castings;

b) a reflective layer, for example a thin layer of metal by vacuum sputtering or vapor deposition, is applied to the functional surface of the matrix, the choice of material depending on the purpose of the optics;

c) the matrix is placed in a separate mold, or in the case of a drop, the mold is applied to the matrix.

2. Preparation of thermoactive casting material and vacuum casting:

⁽ a) the individual components of the casting material are mixed together, After the addition of the hardener and the catalyst, the casting mass is homo | genizates;

(B) the homogenised casting mass is poured into a mold in a vacuum chamber and cured; j

C) after curing, the casting is removed from the mold and removed from the die, including the metal reflective layer, which, due to the greater adhesion forces to the casting mass, remains permanently on the casting, after which the casting is usually further cured.

In the manufacture of each additional mirror optic, step 1b) begins. For smaller casting quality requirements, some partial operations may be omitted, such as tempering or vacuuming during casting and casting. In series production, it is advantageous to use a stream process in which a part of the matrices is prepared in operations 1b) and 1c) and a part of the matrices in the previous cycle provided with a metal layer are used in operations 2a), 2b) and 2c).

Some of the thermoreactive resins curable at normal or elevated temperature, such as epoxy, polyester, polyurethane, may be used as the base of the casting material. In order to be suitable for the production of the mirror optics according to the invention, it is necessary to treat it with fillers, plasticizers and pigments in the simultaneous use of a hard and didlo-catalyst curing system in order to achieve two important properties - high adhesion to metal reflective coating and linear thermal expansion close to the coefficient of glass. The first characteristic is necessary for removing the metal reflective layer from the matrix and its firm adherence to the casting, the second characteristic guarantees the necessary minimum stress in the glass matrix system - the metal reflective layer - casting, and minimal surface deformation. Just too great stress differences in the various materials cause damage to the polished surface of the dies when the glass core is molded according to the prior art. In addition, excessive tension would cause wrinkling or tearing of the thin metal layer. In addition to the mentioned properties, the casting material must have good shape stability, low shrinkage and suitable technological parameters.

Example 1:

Optics:

hm.d.

hm.d. 10 hm.d. 80 hm.d. 4 hm.d.

hollow parabolic mirror, 200 mm

optical glass, ground and optically polished

50 nm thin film deposited by vacuum evaporation of 99.99% pure aluminum

Casting material:

Ingredients

A. epoxy resin ChS Epoxy 110 epoxy resin ChS Epoxy 2000 dibutyl phthalate fused quartz ground

B, latent catalyst AT 50 í Technological parameters and procedure:

The base casting mixture is prepared by mixing the individual components of Part A and evacuating the mixture at 125 ° C and a vacuum of 507 Pa for 20 minutes. After cooling to 50 ° C, component B is added and the mixture is tempered and homogenized at this temperature for minutes.

During the casting time about 10 min. the mass is poured into a mold preheated to 50 ° C in a vacuum chamber at a vacuum of 1014 Pa. The casting is cured at 50 ° C for 2 hours and cured at 100 ° C for 1 hour. Then it is removed from the mold.

Example 2:

Optics:

i X-ray mirror lens type paraboloid, hyperboloid, 0/200 mm.

Matrix:

as in Example 1 Metal layer:

50 nm thin film applied by vacuum vapor deposition of pure gold or nickel with purity

99.98%

Casting material:

the composition and process are the same as in Example 1.

The method of manufacturing the optical members according to the invention allows for repeated production while substantially reducing the manufacturing cost to less than 10% of the cost of the originally individually produced optical mirrors, this advantage being applied especially to hollow mirrors. The field of application of the invention is therefore applications requiring a greater number of the same products and, above all, industrial production, for example the manufacture of special X-ray lenses in which the functional surface is in the form of a cavity. It will also be possible to produce lenses of larger diameters than the galvanic positive shape without the demanding and difficult grinding of internal surfaces requiring a special inaccessible grinding machine.

The production method according to the invention also applies to the mass production of parabolic hollow mirrors with a diameter of 100 to 300 mm for smaller astronomical telescopes.

Claims (1)

SUBJECT Process for producing optical mirror members having a metal functional coating applied in a vacuum, characterized in that a metal functional coating is applied to a negative matrix, on which a filled thermoactive resin is deposited under reduced pressure, which is then removed from said functional coating. matrix.