  (Abridged) We present rest-frame R-band galaxy luminosity function
measurements for three different redshift ranges: 0.5<=z<=0.75, 0.75<=z<=1.0,
and 1.0<=z<=1.5. Our measurements are based on photometric redshifts for ~3000
H-band selected galaxies with apparent magnitudes 17<=H<=20 from the Las
Campanas Infrared Survey. We show that our photometric redshifts are accurate
with an RMS dispersion between the photometric and spectroscopic redshifts of
\sigma_z/(1+z)~0.08. Using galaxies identified in the Hubble Deep Field South
and Chandra Deep Field South regions, we find, respectively, that (7.3\pm 0.2)
% and (16.7\pm 0.4)% of the H<=20 galaxies are at z>=1. We first demonstrate
that the systematic uncertainty inherent in the luminosity function
measurements due to uncertainties in photometric redshifts is non-negligible
and therefore must be accounted for. We then develop a technique to correct for
this systematic error by incorporating the redshift error functions of
individual galaxies in the luminosity function analysis. The redshift error
functions account for the non-gaussian characteristics of photometric redshift
uncertainties. They are the products of a convolution between the corresponding
redshift likelihood functions of individual galaxies and a Gaussian
distribution function that characterizes template-mismatch variance. We
demonstrate, based on a Monte Carlo simulation, that we are able to completely
recover the bright end of the intrinsic galaxy luminosity function using this
technique. Finally, we calculate the luminosity function separately for the
total H-band selected sample and for a sub-sample of early-type galaxies that
have a best-fit spectral type of E/S0 or Sab from the photometric redshift
analysis.
