Projection display device

TL;DR: In this paper, a projection display device constituted so that positional relation between a display picture and a luminescent point picture can be prevented from being fluctuated even when the installing state thereof or the magnification of a lens is changed, whose structure is simple, whose portability is excellent and which is inexpensive.

Abstract: PURPOSE: To provide a projection display device constituted so that positional relation between a display picture and a luminescent point picture can be prevented from being fluctuated even when the installing state thereof or the magnification of a lens is changed, whose structure is simple, whose portability is excellent and which is inexpensive CONSTITUTION: This device is provided with a light source 11, a liquid crystal panel 19 including a polarizing plate 6, the lens 7 used for both of projecting and receiving light, a screen 3, a light pen 2, a polarizing plate for detection 10, a CCD 8 and a control circuit 13 receiving a signal from the CCD 8 and controlling the action of the panel 19 By the lens 7, the light of the display picture from the panel 19 is emitted and projected on the screen 3 Besides, the light from the display picture and the light of a luminescent point from the pen 2 are received and reflected after the pictures thereof are formed on the panel 19 Then, it is made incident on the CCD 8 through the plate 10 The light constituting the display picture is not transmitted through the plate 10