Abstract: The present invention provides a simple design for a temperature-insensitive extrinsic polarimetric strain sensor. The sensing element is a thin sheet of photoelastic material that is bonded to the test object. It is illuminated with linearly polarized light with the polarization direction at 45 degrees relative to the strain-induced fast and slow axes in the photoelastic material. The sensor measures the difference between the strains along these two orthogonal directions. The reduced sensitivity of the sensor to temperature results from the fact that the illumination is perpendicular to the surface of the test object. All polarization components that are parallel to the surface will experience identical refractive index changes due to thermal effects. Consequently, a measurement of the difference in strains along two directions in the surface plane is insensitive to temperature.

Abstract: A recording apparatus wherein a recording head which has been mounted can be identified more precisely by measuring characteristics of the recording head to obtain information for defining a drive condition of the head and storing the characteristics as ID information of the recording head.

Abstract: An apparatus which may be used to display a visual image along the surface of a segmented door, includes a flexible display panel capable of carrying an image. One end of the display panel is connected to the door by a spline affixed to the display panel which is received in a complementary receiving member affixed to the door. Another end of the display panel is connected to the door by a plurality of spaced apart elastic members that connect the display panel to an attaching structure affixed to the door. Tension in the display panel throughout the range of motion of the door is regulated by the elastic members.