  The morphological evolution of dusty disks around young (few Myr-old) stars
is pivotal to better understand planet formation. Since both dust grains and
the global disk geometry evolve on short timescale, high-resolution imaging of
a sample of objects may provide important hints towards such an evolution. We
enlarge the sample of protoplanetary disks imaged in polarized light with
high-resolution by observing the Herbig Ae/Be stars HD163296, HD141569A, and
HD150193A. We integrate our data with previous datasets to paint a larger
picture of their morphology. We report a weak detection of the disk around
HD163296 in both H and Ks band. The disk is resolved as a broken ring structure
with a significan surface brightness drop inward of 0.6 arcsec. No sign of
extended polarized emission is detected from the disk around HD141569A and
HD150193A. We propose that the absence of scattered light in the inner 0.6
arcsec around HD163296 and the non-detection of the disk around HD150193A may
be due to similar geometric factors. Since these disks are known to be flat or
only moderately flared, self-shadowing by the disk inner wall is the favored
explanation. We show that the polarized brightness of a number of disks is
indeed related to their flaring angle. Other scenarios (such as dust grain
growth or interaction with icy molecules) are also discussed. On the other
hand, the non-detection of HD141569A is consistent with previous datasets
revealing the presence of a huge cavity in the dusty disk.
