A flat panel display embedding an image sensor, the flat panel display further comprising: a display panel including a display area and a non-display area; and a directional optical substrate including: a cover plate having a length along a length axis and a width along a width axis; a light radiating film (VHOE); a light incident film (CHOE) disposed at one lateral side of the light radiating film (VHOE), under the cover plate; and a low refractive layer disposed under the light radiating film (VHOE) and the light incident film (CHOE), and having a refractive index lower than the cover plate and the light radiating film (VHOE), wherein the flat panel display further comprises a light source disposed at the lateral side of the display panel, or disposed under the display panel as facing with the light incident film (CHOE), wherein the light incident film (CHOE) includes a first holographic pattern for converting incident light to a propagating light having an incident angle satisfying an internal total reflection condition of the cover plate, and for sending the propagating light to the cover plate, wherein the light radiating film (VHOE) includes a second holographic pattern for converting some of the propagating light into sensing light having a reflection angle which satisfies a total reflection condition at the top surface of the cover plate and a transmitting condition through the low refractive layer, wherein at least one photo sensor is disposed in the display panel located under the directional optical substrate for detecting the sensing light, wherein the length axis of the directional optical substrate corresponds to a length axis of the display panel, wherein the width axis of the directional optical substrate corresponds to a width axis of the display panel, wherein the directional optical substrate is attached on a top surface of the display panel; wherein the length of the cover plate corresponds to the length of the display pane1 and the width of the cover plate corresponds to the width of the display panel; wherein the size of the light radiating film (VHOE) corresponds to the display area; wherein the light incident film (CHOE) is disposed outside of the display area. a display panel including a display area and a non-display area; and a directional optical substrate including: a cover plate having a length along a length axis and a width along a width axis; a light radiating film (VHOE); a light incident film (CHOE) disposed at one lateral side of the light radiating film (VHOE), under the cover plate; and a low refractive layer disposed under the light radiating film (VHOE) and the light incident film (CHOE), and having a refractive index lower than the cover plate and the light radiating film (VHOE), a cover plate having a length along a length axis and a width along a width axis; a light radiating film (VHOE); a light incident film (CHOE) disposed at one lateral side of the light radiating film (VHOE), under the cover plate; and a low refractive layer disposed under the light radiating film (VHOE) and the light incident film (CHOE), and having a refractive index lower than the cover plate and the light radiating film (VHOE), wherein the flat panel display further comprises a light source disposed at the lateral side of the display panel, or disposed under the display panel as facing with the light incident film (CHOE), wherein the light incident film (CHOE) includes a first holographic pattern for converting incident light to a propagating light having an incident angle satisfying an internal total reflection condition of the cover plate, and for sending the propagating light to the cover plate, wherein the light radiating film (VHOE) includes a second holographic pattern for converting some of the propagating light into sensing light having a reflection angle which satisfies a total reflection condition at the top surface of the cover plate and a transmitting condition through the low refractive layer, wherein at least one photo sensor is disposed in the display panel located under the directional optical substrate for detecting the sensing light, wherein the length axis of the directional optical substrate corresponds to a length axis of the display panel, wherein the width axis of the directional optical substrate corresponds to a width axis of the display panel, wherein the directional optical substrate is attached on a top surface of the display panel; wherein the length of the cover plate corresponds to the length of the display pane1 and the width of the cover plate corresponds to the width of the display panel; wherein the size of the light radiating film (VHOE) corresponds to the display area; wherein the light incident film (CHOE) is disposed outside of the display area.