Clear HSR optical grade filters offer a robust, high temperature, high scratch and impact resistant material. It is especially suited to LCD's and other display applications where these characteristics are of particular importance.
LCD's often suffer from a number of problems:
 - Soft front surface polariser - can be subject to damage from scratching, dirt, moisture, finger marks etc
- Front surface reflections - in certain lighting conditions these may cause display reading difficulties
- Restricted viewing angles - caused by LCD construction and method of operating
- Possible Ultra Violet degradation in strong sunlight
- Shielding from electromagnetic interference
- Sourcing of bezels - not always possible or feasible with so many different LCD sizes available
Choice of Clear HSR
Clear HSR has both outstanding abrasion resistance, up to 20 times that of acrylics, and excellent impact resistance. It is also chemically resistant, being immune to the effects of virtually all common solvents. Furthermore, it is low density, approximately half that of glass, and exhibits optical properties comparable to crown glass. It's maximum continuous operating temperature is in excess of 100oC.
Clear HSR is available with selected optional cast-in non glare finishes to overcome front surface reflections. These finishes can improve readability whilst offering advantages in that they cannot chip, peel or rub off.
Clear HSR is cast in-house down to 0.5mm thickness for application where maximum viewing angle is required or where space is at a premium. Thicker filters are manufactured for applications where impact resistance takes priority. Tight thickness tolerances are supplied for specialised applications.
An optional Ultra-Violet inhibitor is also available to restrict potentially harmful UV rays when certain displays are operated out of doors in strong sunlight conditions.
A further option incorporates a blackened stainless steel mesh for electromagnetic shielding. Full edge termination services are available. These mesh filters typically give protection of 60-70dB over the frequency range 100KHz to 1GHz. Effective shielding is becoming increasingly important with the introduction of new legislation.
Technical data - Clear HSR
| Mechanical Properties | Test | Units | Values |
| Abrasion resistance |
D1033 |
x Acrylic |
20 |
| Harness |
D785 |
Rockwell |
M95-M100 |
| Tensile strength |
D638 |
MPa |
34-41 |
| Compressive strength |
D695 |
MPa |
155 |
| Flexural Yield strength |
D790 |
MPa |
52-59 |
| Flexural modulus |
D790 |
GPa |
17-23 |
| Thermal properties |
Test |
Units |
Values |
| Max recommended operating temp (no load) |
|
|
100oC |
| Intermittent (1hr) |
|
|
150oC |
| Specific heat |
C351 |
Kj/Kg/K |
2.3 |
| Coefficient of linear thermal expansion |
D696 |
Linear coeff/oC |
8 - 14x10-5 |
| Thermal conductivity |
C177 |
J/S/M/K |
0.2 |
| Burning rate |
D635 |
mm/min |
<25 |
| Combustion (self ignition) |
D1829 |
oC |
382 |
| Other Properties |
Test |
Units |
Values |
| Specific gravity @ 25oC (glass) |
D792 |
g/cm3 |
1.31 (2.5) |
| Refractive index @ 546nm @ 20oC (glass) |
D542 |
% |
1.500 (1.52) |
| Light transmission |
|
|
90 |
Resistance to chemical reagents
% increase in weight after 7 days immersion at 25oC
| Acid | Solvents |
| 30% sulphuric acid |
0.5% |
95% ethyl alcohol |
0.1% |
| 10% nitric acid |
0.7% |
Acetone |
0.5% |
| 10% hydrochloric acid |
0.4% |
Carbon tetrachloride |
0.6% |
| Alkali | Gasoline | 0.1% |
| 10% ammonium hydroxide |
0.8% |
Benzene |
0.7% |
| 10% sodium hydroxide |
0.5% |
Toluene |
0.6% |
Standard stock thicknesses: 0.5, 1.0, 1.5, 2.0, 3.0mm
Other non-standard thickness and tight tolerances available on request
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