Back to results
US 4,428,673 AGranted
Light diffusion device
AssigneeHajime Industries Ltd.
InventorHajime Yoshida
Life of this patent
Estimating the term…
Abstract
A light diffusion device has a plurality of rough surfaces with different roughnesses which are placed at a light source side of an object to be inspected. The plurality of rough surfaces consecutively diffuse the light emitted from the light source. The diffused light then passes the inspection zone of the object to which a photosensing means is faced from the opposite side to the light source, into which the diffused light is introduced from the light diffusion device after passing the inspection zone of the object.
Claims13
A light diffusion device for interposition between a light source and a transparent object comprising:
- at least one light transmitting plate;
- first and second rough surfaces on said at least one light transmitting plate;
- light from said light source passing progressively through said first rough surface and then through said second rough surface toward said object;
- said first rough surface being effective for producing a first degree of light diffusion;
- said second rough surface being effective for producing a second degree of light diffusion;
- and
- a roughness of said second rough surface being substantially finer than a roughness of said first rough surface whereby said second degree of light diffusion is substantially greater than said first degree of light diffusion and rough surfaces on said object are thereby prevented from interfering with an inspection of said object.
4 more elements
Dependencies are inferred from the claim text.