Patent ID: 8189250

Claim:
A recording/playback apparatus comprising: light-generating and intensity-modulating means for generating, in response to incident light from a light source, signal light and reference light to be shined on a hologram recording medium, wherein during recording, the light-generating and intensity-modulating means generates the signal light by performing light intensity modulation for each pixel unit in accordance with record data and generates the reference light by performing light intensity modulation for each pixel unit so that the reference light has a predetermined light-intensity modulation pattern, the reference light being used for recording data to the hologram recording medium through interference fringes formed together with the signal light, and during playback, the light-generating and intensity-modulating means generates the reference light having the predetermined light-intensity modulation pattern, the reference light being used for obtaining playback light from the hologram recording medium; and phase modulating means for performing phase modulation on the signal light and the reference light on a basis of the pixel unit by using first to nth phase modulation levels, where n is a natural number of 2 or greater, wherein the phase modulating means performs the phase modulation on the reference light, with all pixels corresponding to the reference light being divided and set using random phase units, each having a specific pixel array pattern having at least two pixels represented by N horizontal pixels by M vertical pixels, where N and M are natural numbers of 1 or greater, with the number of pixels corresponding to each of the first to nth phase modulation levels in each random phase unit being set to be common to the random phase units, and with the array pattern of the pixels corresponding to the first to nth phase modulation levels being set to be random for each random phase unit.