  We report an infrared reflection spectroscopy study of
La$_{1/2}$Ca$_{1/2}$MnO$_3$ over a broad frequency range and temperature
interval which covers the transitions from the high temperature paramagnetic to
ferromagnetic and, upon further cooling, to antiferromagnetic phase. The
structural phase transition, accompanied by a ferromagnetic ordering at
T$_C$=234 K, leads to enrichment of the phonon spectrum. A charge ordered
antiferromagnetic insulating ground state develops below the N\'eel transition
temperature T$_N$=163 K. This is evidenced by the formation of charge density
waves and opening of a gap with the magnitude of 2$\Delta_0$ = (320 $\pm$ 15)
cm$^{-1}$ in the excitation spectrum. Several of the infrared active phonons
are found to exhibit anomalous frequency softening. The experimental data
suggest coexistence of ferromagnetic and antiferromangetic phases at low
temperatures.
