| 摘要 |
The invention describes a lead-free and arsenic-free special short flint glass with a refractive index 1.60<=N<SUB>d</SUB><=1.65, an Abbe number of 41<=nu<SUB>d</SUB><=52, a relative partial dispersion 0.551<=P<SUB>gF</SUB><=0.570 in the blue spectral region, a relative partial dispersion 0.507<=P<SUB>Cs</SUB><=0.525 in the red spectral region, a negative deviation of the relative partial dispersion from the normal line DeltaP<SUB>g,F</SUB><=-0.0045 and an improved chemical resistance which has the following composition (in % by weight): <tables id="TABLE-US-00001" num="00001"> <table frame="none" colsep="0" rowsep="0"> <tgroup align="left" colsep="0" rowsep="0" cols="3"> <colspec colname="offset" colwidth="21pt" align="left"/> <colspec colname="1" colwidth="119pt" align="left"/> <colspec colname="2" colwidth="77pt" align="center"/> <THEAD> <ROW> <ENTRY/> <entry namest="offset" nameend="2" align="center" rowsep="1"/> </ROW> </THEAD> <TBODY VALIGN="TOP"> <ROW> <ENTRY/> <ENTRY>SiO<SUB>2</SUB></ENTRY> <ENTRY>>50-65 </ENTRY> </ROW> <ROW> <ENTRY/> <ENTRY>Al<SUB>2</SUB>O<SUB>3</SUB></ENTRY> <ENTRY>0-7</ENTRY> </ROW> <ROW> <ENTRY/> <ENTRY>B<SUB>2</SUB>O<SUB>3</SUB></ENTRY> <ENTRY>0-6</ENTRY> </ROW> <ROW> <ENTRY/> <ENTRY>Li<SUB>2</SUB>O</ENTRY> <ENTRY>0-6</ENTRY> </ROW> <ROW> <ENTRY/> <ENTRY>Na<SUB>2</SUB>O</ENTRY> <ENTRY> 3-11</ENTRY> </ROW> <ROW> <ENTRY/> <ENTRY>K<SUB>2</SUB>O</ENTRY> <ENTRY>0-6</ENTRY> </ROW> <ROW> <ENTRY/> <ENTRY>MgO</ENTRY> <ENTRY> 0-12</ENTRY> </ROW> <ROW> <ENTRY/> <ENTRY>CaO</ENTRY> <ENTRY> 1-12</ENTRY> </ROW> <ROW> <ENTRY/> <ENTRY>BaO</ENTRY> <ENTRY>0-8</ENTRY> </ROW> <ROW> <ENTRY/> <ENTRY>La<SUB>2</SUB>O<SUB>3</SUB></ENTRY> <ENTRY> 0-15</ENTRY> </ROW> <ROW> <ENTRY/> <ENTRY>Ta<SUB>2</SUB>O<SUB>5</SUB></ENTRY> <ENTRY> 0-10</ENTRY> </ROW> <ROW> <ENTRY/> <ENTRY>Nb<SUB>2</SUB>O<SUB>5</SUB></ENTRY> <ENTRY> 4-20</ENTRY> </ROW> <ROW> <ENTRY/> <ENTRY>ZrO<SUB>2</SUB></ENTRY> <ENTRY>>10-20 </ENTRY> </ROW> <ROW> <ENTRY/> <ENTRY>Sigma(CaO + MgO + BaO)</ENTRY> <ENTRY> 1-25</ENTRY> </ROW> <ROW> <ENTRY/> <ENTRY>Sigma(Na<SUB>2</SUB>O + K<SUB>2</SUB>O + Li<SUB>2</SUB>O)</ENTRY> <ENTRY> 3-20</ENTRY> </ROW> <ROW> <ENTRY/> <ENTRY>SiO<SUB>2</SUB>/(ZrO<SUB>2 </SUB>+ La<SUB>2</SUB>O<SUB>3 </SUB>+ Nb<SUB>2</SUB>O<SUB>5 </SUB>+ Ta<SUB>2</SUB>O<SUB>5</SUB>)</ENTRY> <ENTRY>1.5-2.3.</ENTRY> </ROW> <ROW> <ENTRY/> <entry namest="offset" nameend="2" align="center" rowsep="1"/> </ROW> </TBODY> </TGROUP> </TABLE> </TABLES>
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