Glass with improved total pitch stability
Described herein are alkali-free, boroalumino silicate glasses exhibiting desirable physical and chemical properties for use as substrates in flat panel display devices, such as, active matrix liquid crystal displays (AMLCDs) and active matrix organic light emitting diode displays (AMOLEDs). In accordance with certain of its aspects, the glasses possess excellent compaction and stress relaxation properties.
1. A glass exhibiting the following performance criteria:
A: Compaction in the LTTC less than or equal to 5.5 ppm
B: Compaction in the HTTC less than or equal to 40 ppm
C: Less than 50% of an induced stress relaxed in the SRTC.
2. The glass of claim 1 comprising, in mole percent on an oxide basis: SiO 2 50-85, Al 2 O 3 0-20, B 2 O 3 0-10, MgO 0-20, CaO 0-20, SrO 0-20, BaO 0-20, where SiO 2 , Al 2 O 3 , B 2 O 3 , MgO, CaO, SrO and BaO represent the mole percents of the oxide components.
3. The glass of claim 1 comprising, in mole percent on an oxide basis: SiO 2 68-74, Al 2 O 3 10-13, B 2 O 3 0-5, MgO 0-6, CaO 4-9, SrO 1-8, BaO 0-5, where SiO 2 , Al 2 O 3 , B 2 O 3 , MgO, CaO, SrO and BaO represent the mole percents of the oxide components.
4. The glass of claim 1 , wherein As 2 O 3 and Sb 2 O 3 comprise less than about 0.005 mol %.
5. The glass of claim 1 , wherein Li 2 O, Na 2 O, K 2 O, or combinations thereof, comprise less than about 0.1 mol % of the glass.
6. The glass of claim 1 wherein
1.05≦(MgO+CaO+SrO+BaO)/Al 2 O 3 ≦1.2,
where Al 2 O 3 , MgO, CaO, SrO and BaO represent the mole percents of the oxide components.
7. The glass of claim 1 wherein
1.05≦(MgO+CaO+SrO+BaO)/Al 2 O 3 ≦1.4,
where Al 2 O 3 , MgO, CaO, SrO and BaO represent the mole percents of the oxide components.
8. The glass of claim 1 having an anneal point in excess of 765° C.
9. The glass of claim 1 wherein T 35k −T liq >0.25T 35k −225° C.
10. The glass of claim 1 having a T 35k <1310° C.
11. The glass of claim 1 having a CTE over the 0-300° C. temperature range between 28-42×10 −7 /° C.
12. The glass of claim 1 having transmission at 300 nm of greater than 50% at a thickness of 0.5 mm.
13. The glass of claim 1 having a density between 2.3 and 2.6 g/cc.
14. The glass of claim 1 having a Young's′ modulus of between 75-85 GPa.
15. The glass of claim 1 wherein the compaction in the LTTC is less than or equal to 5 ppm.
16. The glass of claim 1 wherein the compaction in the LTTC is less than or equal to 4.6 ppm.
17. The glass of claim 1 wherein the compaction in the HTTC is less than or equal to 38 ppm.
18. The glass of claim 1 wherein the compaction in the HTTC is less than or equal to 36 ppm.
19. The glass of claim 1 wherein less than 45% of an induced stress is relaxed in the SRTC.
20. The glass of claim 1 wherein less than 40% of an induced stress is relaxed in the SRTC.