Here at the Second Story media lab, we have been conducting tests to determine the effectiveness of the Visual Planet VIP touch foil when it is mounted directly in front of an LCD panel. A video was created which documents the test setup and the testing procedure:
Mounting a VIP touch foil in front of an LCD panel has many benefits over traditional touch screens, but there was concern that the proximity of the VIP foil to the LCD screen would introduce noise and effect the sensitivity of the touch foil. These tests informed us that when the VIP is to be located 1/2″ from the surface of the screen, the touch sensitivity is still adequate for user interaction.
– (2) 46″ LCD NEC X461UN low-bezel display
– (1) 46″ Visual Planet VIP foil (projected capacitive film)
– (1) 1/4″ clear acrylic sheet
– (temporarily) mount the VIP on the back of the acrylic sheet
– mount the sheet 1/2″ from the display surface of the LCD panel
– conduct experiments with touch sensitivity and accuracy
– mounting the VIP foil 1/2″ from the display surface of the LCD panel had little effect on the touch sensitivity and performance.
– some noise was apparent when the display was turned on _after_ the test was initiated (this introduced new noise source which the VIP foil has to adjust to)
– single finger/light touches were the most difficult to pick up.
– if there is any significant displacement of the substrate (the glass or acrylic surface to which the VIP foil is adhered) there is a considerable amount of noise and the foil does not function well. This is most apparent when you apply significant pressure to the surface the acrylic sheet as shown in this test video.
– the “tag” on the side of the VIP foil which the electronics and USB connector are on can also pick up electrical noise and effect touch data. This flap will need to be isolated from the screen and surrounding metal frame when it is run around the edge of (and behind) the LCD screen.
– If there is a metal frame immediately around the viewable area of the LCD panel, the VIP foil can not fill the width of the screen: this is because any metal frame on either side of the glass which will likely introduce noise to the VIP foil signal and reduce sensitivity. The VIP foil typically needs a 2″ buffer between the active area of the foil and any metal framing surrounding the glass and screen.
– The actual substrate used in most installations will be 3/8″ safety glass rather than the 1/4″ acrylic used in this test. Hopefully this, along with the fact that it is typically supported continuously along its length, will prevent any significant displacement of the substrate when it is subjected to high pressure touches.