| 摘要 |
<p>PCT No. PCT/DE80/00085 Sec. 371 Date Feb. 7, 1981 Sec. 102(e) Date Feb. 2, 1981 PCT Filed Jun. 6, 1980.An anti-entry device for surfaces in which the edge of the surface to be protected is provided with light-reflecting layers which conduct the light coming from a source of light to a receiver, said receiver being connected to an alarm which is activated when the light to said receiver is disturbed. In order to make the anti-entry device insensitive to adjustment, the light-reflecting layers are formed of elements which reflect an impinging ray of light independently of their angular position, in the plane extending between the layers and parallel to the direction of incidence thereof. These elements are developed as mirror strips which contain 90 DEG angle mirrors or 90 DEG prisms as reflecting elements. Several of such mirrors or prisms can be combined in a single mirror strip. The anti-entry device is used for the securing of surfaces, such as windows, as well as machines and open-field areas. The anti-entry device is adapted to be portable, particularly for the last-mentioned purpose of use.</p> |
