An autostereoscopic display shutter comprising: a first switchable aperture array having a plurality of switchable aperture elements and forming part of a first switchable parallax barrier, each switchable aperture element of the first switchable aperture array having a faster switching time from a substantially transparent state, in which the switchable aperture element forms a corresponding aperture, to a substantially opaque state than its slower switching time from a substantially opaque state to a substantially transparent state, and a second switchable aperture array having a plurality of switchable aperture elements and forming part of a second switchable parallax barrier, each switchable aperture element of the second switchable aperture array having a faster switching time from a substantially opaque state to a substantially transparent state, in which the switchable aperture element forms a corresponding aperture, than its slower switching time from a substantially transparent state to a substantially opaque state, wherein the switchable aperture elements of said first switchable aperture array at least partially overlap with respective switchable aperture elements of said second switchable aperture array; and drive means arranged in use to drive the first and second switchable aperture arrays wherein, for each aperture formed in one of the first and second switchable aperture arrays, wherein the aperture is a first aperture and is formed by opening of one or more of the switchable aperture elements of said one of the first and second switchable aperture arrays, and wherein the first aperture has a first width: a number of switchable aperture elements are opened in the other of the first and second switchable aperture arrays to thereby form a corresponding second aperture in the other of the first and second switchable aperture arrays, the second aperture wholly overlapping the first aperture and having a second width greater than the first width, wherein one of the first and second switchable aperture arrays has a higher contrast ratio than the other of the first and second switchable aperture arrays, and wherein the slower switching time of the switchable aperture elements of the switchable aperture array with the higher contrast ratio is less than the slower switching time of the other switchable aperture array. a first switchable aperture array having a plurality of switchable aperture elements and forming part of a first switchable parallax barrier, each switchable aperture element of the first switchable aperture array having a faster switching time from a substantially transparent state, in which the switchable aperture element forms a corresponding aperture, to a substantially opaque state than its slower switching time from a substantially opaque state to a substantially transparent state, and a second switchable aperture array having a plurality of switchable aperture elements and forming part of a second switchable parallax barrier, each switchable aperture element of the second switchable aperture array having a faster switching time from a substantially opaque state to a substantially transparent state, in which the switchable aperture element forms a corresponding aperture, than its slower switching time from a substantially transparent state to a substantially opaque state, wherein the switchable aperture elements of said first switchable aperture array at least partially overlap with respective switchable aperture elements of said second switchable aperture array; and drive means arranged in use to drive the first and second switchable aperture arrays wherein, for each aperture formed in one of the first and second switchable aperture arrays, wherein the aperture is a first aperture and is formed by opening of one or more of the switchable aperture elements of said one of the first and second switchable aperture arrays, and wherein the first aperture has a first width: a number of switchable aperture elements are opened in the other of the first and second switchable aperture arrays to thereby form a corresponding second aperture in the other of the first and second switchable aperture arrays, the second aperture wholly overlapping the first aperture and having a second width greater than the first width, a number of switchable aperture elements are opened in the other of the first and second switchable aperture arrays to thereby form a corresponding second aperture in the other of the first and second switchable aperture arrays, the second aperture wholly overlapping the first aperture and having a second width greater than the first width, wherein one of the first and second switchable aperture arrays has a higher contrast ratio than the other of the first and second switchable aperture arrays, and wherein the slower switching time of the switchable aperture elements of the switchable aperture array with the higher contrast ratio is less than the slower switching time of the other switchable aperture array.