DE4118161A1 - Black-edged lens - has sheet material e.g. of soft PVC for absorbing distorting light glued to edges - Google Patents

Abstract

The black-edged lens is conventionally-produced by milling, polishing, centring, cleaning and coating. Sheet-material absorbing distorting light is glued to the edges. Its index of refraction in relation to that of the lens material can be such as to absorb the greater portion of the light reaching it. Dependent on the wavelength, the edges can be so coated as to avoid total reflection. The sheet can be of soft PVC, coated with acrylic glue. It can be roughened, contain magnetic particles, and be electroconductive. It can be cut by a laser beam to the desired dimensions before fitting. ADVANTAGE - Can be completely automated.

Description

The invention relates to the blackening of the edges of optical parts, which in a known manner in the milling process stages, Polishing, centering, cleaning and coating are made.

The necessity of blackening the edges of optical components, especially of lenses, has long been known. Mostly done an application of a quick-drying, solvent-containing Lacquers manually with a brush, the lenses using a support body, Plug chucks, collets etc. individually on a motor driven Rotary table are temporarily installed. The disadvantage is in addition to the high manual effort, especially the poor qualitative execution. The paint thickness is fluctuating, from what directly deterioration of the centering of the lenses in the System and thus aberrations result. The disadvantage is also the use of solvent-based paints, the modern ones Contradicts environmental requirements. The viscosity is factual not controllable. From today's perspective, this procedure is not automation friendly.

The edge blackening is occasionally caused by rubbing in the milled edge surfaces carried out with powdered graphite. The blackening effect is not sufficient, apart from the unpleasant one Dealing with the heavily dusting graphite. An additional cleaning the optical functional surfaces is inevitable, though the process reveals approaches to automation.

It is also known to use the ink jet printing process. A disadvantage is the unresolved contradiction between the Requirements for those for paper printing and glass printing necessary properties of the ink. This affects above all Drying times. So far, the inkjet heads have not succeeded to prepare the printer especially for optical coatings.  

It is also known to use fiber pens for brushing the lens edges to use. The manual effort is also high here there are quality defects.

The invention relates to rim-black optical parts, in particular Lenses, and the part of their manufacturing process where the Blackening of the surfaces and edges is made. In an the process stages milling, polishing, Centering, cleaning and coating performed, the Method is characterized in that the blackening of the Edge and the edges by gluing one the stray light swallowing film is made.

The film is "centered" immediately after the d. H. glued on after shaping the final edge geometry. After the film has been stuck on, the optical part has the property that the majority of the stray light that is transmitted to the Edges, chamfers, conical surfaces etc. is normally reflected and thus undesirable for brightening and reducing contrast contributes, is eliminated. The film is according to the invention with a Dye provided, the optimal adjustment for this purpose the refractive index ratios of optical material and film guaranteed.

The film is self-adhesive and also exists in the rest Manufacturing process of the optical components and in later use occurring loads permanently and without damage. To these loads include mechanical and chemical Cleaning procedures, also under the influence of ultrasound Influence of ultra-high vacuum and gluing when anti-reflective, Temperature fluctuations etc.

The film is thin; less than 0.1 mm; and tolerated closely (Thickness tolerance <0.01 mm). This ensures that the Centering condition of the lenses (deviation of the forme cylinder from the optical axis) is only slight. That contributes directly Improving the imaging properties of the optical system at.  

The optical part and the process for its manufacture is still characterized in that the packaging of the film immediately before sticking by a programmable cutting knife-containing Device or by laser cutting. This is an adjustment of the necessary film width and length to the respective component, even with small lot sizes possible. The accuracy of the cut is 0.01 mm.

The methodology is applicable to all optical media (glass, crystals, Quartz and optical plastics) applicable.

The process is environmentally friendly, i. H. CFC-free and solvent-free Slides are a matter of course.

The invention allows complete automation of the The process of "blackening the edges" does not actually lead to an increase the total effort of lens production if the invention Organizationally procedures directly in the process of lens centering is included. The lenses are on the centering machine clamped, the diameters and chamfers are freely accessible. The creation of the protective bevels can largely be omitted without that the interests of occupational safety are disrupted.

A special business effect is created by the extensive protection of the lenses against chipping when careless Dealing with them. The risk of destruction due to edge damage is actually extraordinarily large in the optics process, if you take into account how often the lenses in the usual non-automated processes directly affected by humans and be treated until they finally take their final place in the Find optics system.

The film is optionally provided with magnetic particles. This results in the possibility, particularly in the case of conical ones optical parts, these directly by means of the magnetic effect to be fixed in steel frames.  

If necessary, the film is electrically conductive executed, which creates an easy way electrical signals, for example for aperture value transmission transfer.

The optical part with the film is further characterized by that the film has at least one externally visible graduation mark contains, as an indelible guide for complicated Testing and assembly operations is advantageous.

Furthermore, the optical part is characterized in that the film is provided with a barcode identification. So that's it Identification of the optical parts finally realizable. This Effect is particularly significant in optical systems that must be made using melting combinations. The Identification number is advantageous when laser cutting the Films attached directly to the centering machine.

The film may be double-adhesive. With conical Optical parts therefore have the option of directly without the parts other aids in a correspondingly shaped version to add permanently.

The invention is intended to be explained below using an exemplary embodiment are explained in more detail.

Figure 1 shows part of the device necessary for the method according to the invention. The optical part 1 is clamped between the clamping bells 2 and 3 in a known manner on the centering machine and is set in rotation by the centering machine with the motor 4 . The film 5 is removed from a supply roll in a manner not shown in detail and is guided past the outer diameter 6 of the optical part 1 . With the help of the laser beam 7 , which is focused on the film 5 , the film 5 is cut so that the necessary width and length for wrapping the optical part 1 is created.

The laser 8 (preferably a CO₂ laser with approximately 200 W out-put) provides the necessary energy for this, while the modulator and scanning unit 9 directs the laser beam 7 onto the interface. The control of the entire device (laser 8 , modulator and scanning unit 9 and motor 4 ) is carried out with the operating device 10 .

Immediately downstream of the interface is the pressure roller 11 , which, however, is shown offset by 180 ° in Figure 1. This pressure roller 11 presses the film 5 passing by against the outer diameter 6 of the optical part 1 , as a result of which the film 5 and the optical part 1 are permanently bonded.

In picture 2 it can be seen how the lens-shaped optical part 1 is enclosed by the film 5 on the outside diameter 6 and on the edges 12 and 13 , so that the desired main effects such as the annihilation of the stray light 14 and the protection against damage at the edges 12 and 13 can be guaranteed.

The film 5 consists of a permanently stable polymer tape, which is dyed in such a way that incident light is swallowed in the working wavelength range of the optical system to be produced. The band is black for the visible area.

The film 5 is self-adhesive and also has good adhesive properties when the optical part 1 on the centering machine is still wetted by the coolant from the centering process. The optical part can also consist of optical glass, quartz, crystal or plastic.

The film 5 is closely tolerated with regard to its geometric parameters. The thickness is preferably 0.06 mm ± 0.01 mm, the length and the width are also produced in the method according to the invention by means of laser cutting to an accuracy of 0.01 mm.

Further properties of film 5 are its compatibility with optical putties and frame adhesives and the long-term resistance to mechanical and chemical cleaning techniques commonly used in the optical industry.

For certain applications, it can be advantageous to provide the film 5 with magnetic particles, so that the optical part 1 , which can also be conical, for example, is joined directly into steel frames by means of the magnetic effect.

For other special applications, the film 5 can also be made electrically conductive. In this way, for example, electrical signals of an aperture value transmission can easily be forwarded.

It is particularly advantageous for the entire manufacturing process of optical systems if the film 5 is provided with at least one graduation ( 15 ) on the outside. This significantly simplifies the assembly of high-performance lenses, since certain azimuth positions of the lenses in the lens are determined by measurement and calculation and must be retained until the system is finally installed.

A further advantage results according to the invention if the laser cutting device is used at the same time to apply an identification number to the lens, ie to the outer surface of the film 5 . This identification number can be in the form of a bar code. Organizationally, there are extraordinary advantages for the optics process, especially with regard to systems that are unmistakably associated with melting combinations or other assignments.

Claims (16)

1. Border black optical part, which is manufactured in a known manner in the milling, polishing, centering, cleaning and coating process stages, characterized in that a film swallowing the stray light is glued onto the edge and / or the edges. 2. Optical part according to claim 1, characterized in that the refractive index of the film in terms of its optical effect the optical medium of the component is adapted so that the essential part of the stray light, which the glued surfaces and reaches edges, is swallowed. 3. Optical part according to claim 2, characterized in that depending on the wavelength, the edges of the optical part so are coated so that total reflection is avoided. 4. Optical part according to claim 1, characterized in that the film is self-adhesive. 5. Optical part according to claim 5, characterized in that the film is double adhesive. 6. optical part according to one or more of the preceding claims, characterized in that the film is thinner than 0.1 mm and a thickness tolerance smaller 0.01 mm. 7. optical part according to one or more of the preceding claims, characterized in that the film and / or the film adhesive for the optical cement and / or for adjacent socket adhesive is compatible.   8. optical part according to one or more of the preceding claims, characterized in that the film is preferably made of PVC-soft, with acrylic adhesive coated, is produced. 9. optical part according to one or more of the preceding claims, characterized in that the film is designed as a scratch film. 10. optical part according to one or more of the preceding claims, characterized in that the film is provided with magnetic particles. 11. Optical part according to one or more of the preceding claims, characterized in that the film is electrically conductive. 12. Optical part according to one or more of the preceding claims, characterized in that the film contains at least one externally visible graduation ( 15 ). 13. Optical part according to claim 12, characterized in that the film is provided with a barcode identification. 14. A method for producing an optical part, characterized as a result of that the blackening of the optical part by sticking black or blackened film is produced. 15. A method for producing an optical part according to claim 14, characterized in that sticking the film immediately after the process of Edge centering takes place.   16. A method for producing an optical part according to claim 14 or 15, characterized in that the film immediately before the application to the lenses by means of a programmable and a Device containing cutting knife or by a laser beam assembled, d. H. according to the peripheral surfaces of the Optical part is cut in length and width.