JPS5849842B2 - Manufacturing method of high-resolution scattering plate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a high-resolution scattering plate used in an optical instrument that reproduces images, measurement scales, etc. by projecting transmitted light.

In addition, this type of scattering plate is used in optical instruments to uniformly scatter and illuminate a three-dimensional or flat surface.

It is known to manufacture projection scattering plates by providing a certain roughness on the glass surface by polishing or etching (Opt
ik Vol. 1, p. 238 (1946)).

In another known method for producing projection screens, a film of finely divided inorganic pigments is fixed to a transparent support plate of polymethyl methacrylate by means of a film-forming binder (German Utility Model No. 1834760).

However, the scattering plate manufactured in this way has a half-value angle of 3° to 5°.
The major disadvantage is that it is very small, less than 100°C, and the resolution during image reproduction is also extremely insufficient.

In order to remove this flame, a method is known in which a scattering agent made of a polyester dispersion is added to produce a scattering plate or a matte film from an organic polymer mixture (East German Economic Patent Nos. 51090 and 101333).

This increased the scattering power to a half-power angle of about 25°, but the resolution was somewhat inadequate.

In addition, as the half-value angle increases, the transmittance of the scattering plate or scattering film, and therefore the brightness of the image, decreases extremely.

Finally, the stability of the surface with respect to mechanical, climatic and thermal influences is insufficient, and even supplementary protective treatments do not sufficiently ensure this stability.

Furthermore, in order to improve the abrasion and damage resistance and to improve the adhesion of the scattering coating to the plastic support, the nitrocellulose lacquer has been previously treated with silanes to make it hydrophobic.
It is known to provide a plastic support plate with a diffusion coating consisting of highly dispersed silicic acid finely distributed in the lacquer and wet-dropped (East German Economic Patent No. 112,006).

However, this method also has a drawback in that the transmittance is extremely reduced when the half-value angle is 15 degrees or more.

Additionally, high half-value angles of 15° or more can only be achieved by repeated coatings, which increases the technical and time expenditure.

Additionally, this method is limited to plastic supports.

In another known technical solution, the projection screen consists of a plastic plate or film filled with inorganic pigments, such as, for example, magnesium monoclinic silicate, calcium silicate, barium sulfate, zinc oxide, etc.
No. 01467).

However, the disadvantage in this case is that the high transmittance combined with the insufficient resolution contrast and scattering power (small half-value angle) makes this type of scattering plate suitable for use in optical instruments. do not have.

Finally, projection screens are known (DE 26 14 606) in which a scattering effect is produced by means of a wax component or a crystalline polymer component interposed with a polymer layer and a lens structure engraved on the surface.

However, in this case too, the resolution and transmittance are insufficient.

To summarize, high resolution, at the same time large half-power angle (high scattering power), high transmission (image sharpness), and additional protection measures against mechanical, thermal and climatic influences are required. It can be confirmed that it has been impossible to manufacture a stable scattering plate for transmitted light projection according to the prior art.

The object of the invention is a method for producing a high-resolution scattering plate, which avoids the above-mentioned disadvantages.

Even if the half-value angle is large (even if the scattering power is high), high resolution and high transmittance must be guaranteed at the same time.

The object of the invention is that the half-value angle of the scattering plate can be adjusted selectively and purposefully in the range between 8° and 30°, with a resolution between 22 and 15 line pairs per 1 m71 and a minimum of 50%
The object of the present invention is to provide a method for guaranteeing the transmittance.

In addition, this scattering plate is stable against mechanical, thermal and climatic influences, and the dimensions of the scattering plate are 1, ?, if necessary. It must be possible to get 1 or more.

This problem is solved according to the invention by a method for producing high-resolution scattering plates by applying a scattering lacquer to a glass or plastic support using a free-falling lacquer film, which method has the following characteristics: has.

That is, polymethyl methacrylate transparent lacquer 10
to ~20% by weight, adding crushed quartz with a particle size of 1 to 10 μm and/or 10 to 30 μm while simultaneously adding 0.01 to 0.02% by weight of silicone oil and 1 to 1.5% by weight of a dispersant, In the next step, the viscosity of the scattering lacquer is reduced to 20°C.
253 cP to 133 cP, and the resulting scattering lacquer was measured dry in a casting machine to give a layer thickness of 80 cP.
Apply to support material with ~250μ door.

The scattering plate manufactured according to the present invention has a resolution of at least 22 line pairs/double and a transmittance of at least 80% when the half-value angle is 8°.

For a half-power angle of 300, the resolution is at least 15 line pairs/square and the transmittance is at least 55%.

Uniformity of the optical parameters is guaranteed even for areas greater than 177 I''.

This scattering plate is also scratch and wipe resistant and has 6
It can be used at temperatures up to 0° C. without losing its optical properties.

Example The present invention will be explained in detail based on the following examples.

Example 1 12% by weight of crushed quartz with a viscosity of 1-10 μm was mixed with silicone oil (e.g.
1.5% by weight of a 1% xylene solution of 0) and a sodium aluminum silicate dispersion (e.g. VER
Micro Extender A from Fehrbrützke Chemical Factory
l 0 3 ) with 1.5% by weight in a 25% by weight nitro diluent and this mixture is mixed with a 60% by weight polymethyl methacrylate lacquer (e.g. VER
Mix in LT30) manufactured by Peastarits Nitrogen Factory and stir.

Further nitro dilution is added to adjust the scattering lacquer to a viscosity of between 253 cP and 1 33 cP at 20°C.

This prepared scattering lacquer is applied as a free-falling lacquer film to a support made of glass or plastic in a casting apparatus, the dry scattering film having a thickness between 80 and 100 μm.

The scattering plate thus obtained has a half-value angle of 8° to 100° when the resolution is 22 line pairs/mrtt.

Desirably, the dried scattering plate is recured at 80° C. for 2 to 5 hours.

For contrast improvement or for biomedical reasons, the scattering plate may be colored.

Wophanol or neozabon pigments dissolved in organic solvents are suitable for this purpose.

The pigments are each used as a 1% solution which is added to the scattering lacquer instead of a nitro dilution up to 50%.

Temperature and climate resistance can be increased, depending on the application, by priming the support plate surface with a commercially available matt lacquer or polyvinyl acetate clear lacquer in a layer thickness of 25 to 50 μm before coating with the scattering lacquer. As a result, the scattering plate achieves weather stability of at least 6 days in hot and humid fluctuating weather and temperature resistance of +55°C to -40°C.

This scattering coating is damage resistant and does not require special protection.

Example 2 Using a method similar to Example 1, a scattering lacquer with a particle size of 1 to
It was manufactured and used using 15% by weight of crushed quartz with a 10μ door.

Thus, the layer thickness of the scattering coating in the dry state is 120 to 15
In the case of a 0μ door, a scattering plate with a half-value angle of 20° to 25° was obtained.

The resolution is between 20 and 22 line pairs/mm.

If an equal amount of crushed quartz with particle size between 10 and 30 μm is used, a resolution of 20 line pairs/field can be obtained with the same half-value angle.

Example 3 A scattering plate was manufactured using a scattering lacquer in the same manner as in Example 1.

At this time, the amount of crushed quartz with a viscosity of 1 to 10 μm was 18% by weight.
Then, the layer thickness of the dry scattering coating was increased to 200-250μ.

Scattering plates with half-value angles between 300 and 35° were obtained for resolutions of 15 line pairs/mm or more.

Claims (1)

[Claims] 1. A method for producing a high-resolution scattering plate in which a scattering lacquer is applied to a glass or plastic support using a free-falling lacquer film, in which 10 to 20% by weight of polymethyl methacrylate clear lacquer is mixed with 0.01% silicone oil.
Particle size 1-10μ and/or 10-30μ with simultaneous addition of ~0.02% by weight and 1-1.5% by weight of dispersant
μm of crushed quartz is added, and in the next step the viscosity of the scattering lacquer is adjusted to 253 cP to 133 cP at 20°C, the finished scattering lacquer is measured dry in a casting device and the layer thickness is 80 to 250 μm. A method characterized by applying it to