Patent ID: 6522401
Filing Date: 2003-02-18
Classification: G01J

Abstract:
A light measuring device to measure light radiated from a plane light source, a luminous surface located on a bottom surface of the plane light source, the light measuring device comprising:a photosensor located under the plane light source for generating a signal, the photosensor has a photosensitive surface parallel with the luminous surface on the top of the photosensor; a light shield made of an opaque material located above the photosensitive surface of the photosensor, the light shield having a plurality of apertures; and a control device electrically connected to the photosensor, the control device analyzing the signal from the photosensor so that the control device is able to analyze the light from the plane light source; wherein the light from the luminous surface of the plane light source projects onto the photosensor through the apertures of the light shield to form a plurality of photosensing areas on the photosensor with no image being present between the plane light source and the photosensor, each photosensing area having a corresponding test area on the luminous surface, the control device analyzing the signal to check the light from each corresponding test area on the luminous surface for testing or calibrating the plane light source.