Displacement/quantity of light converter
View Patent ↗A displacement/quantity of light converter in which sensitivity to a micro displacement due to sound of a diaphragm, or the like, can be enhanced easily. In the displacement/quantity of light converter where a light emitting part ( 2 ) and a light receiving part ( 3 ) are disposed oppositely to a diaphragm ( 1 ), light emitted from the light emitting part ( 2 ) and reflected off the diaphragm ( 1 ) is received at the light receiving part ( 3 ), and a displacement of the diaphragm ( 1 ) is converted into an output from the light receiving part ( 3 ), a concave diaphragm is used and the concave face is directed toward the light emitting part ( 2 ) and the light receiving part ( 3 ). According to the arrangement, light emitted from the light emitting part ( 2 ) and reflected off the diaphragm ( 1 ) impinges efficiently on the light receiving part ( 3 ) in the form of focused light.
1. A displacement/light-quantity converter, comprising:
a diaphragm; and
a light emitting part and a light receiving part opposed to the diaphragm,
said light receiving part receiving light emitted from said light emitting part and reflected off said diaphragm, and a vibrational displacement of said diaphragm being converted into a variation of Quantity of light received by said light receiving part,
wherein said diaphragm has a concave surface, and the concave surface is opposed to said light emitting part and said light receiving part, and
wherein the concave surface of said diaphragm is a rotational curved surface that is formed by rotating a curve 360 degrees about a central axis, which passes through a central point between said light emitting part and said light receiving part and is perpendicular to said diaphragm.
2. The displacement/light-quantity converter according to claim 1 , wherein said rotational curved surface is a spherical surface that is formed by rotating a part of a circle 360 degrees about said central axis, the radius of curvature of the circle corresponding with a line connecting the central point between said light-emitting part and said light receiving part to said diaphragm.
3. The displacement/light-quantity converter according to claim 1 , wherein said rotational curved surface is a curved surface that is formed by rotating a part of a curve 360 degrees about said central axis, the curve being composed of any one of a parabola, an ellipse, and another curve or a combination thereof.
4. The displacement/light-quantity converter according to any of claims 1 to 3 , wherein said light emitting part and said light receiving part are incorporated in a single package.
5. The displacement/light-quantity converter according to any of claims 1 to 3 , wherein said light emitting part is composed of a semiconductor laser element.
6. The displacement/light-quantity converter according to any of claims 1 to 3 , wherein said light emitting part is composed of a vertical cavity surface emitting laser element.