Source: http://www.google.com/patents/US7045768?ie=ISO-8859-1
Timestamp: 2015-01-27 06:24:02
Document Index: 292454714

Matched Legal Cases: ['art 2', 'art 3', 'art 2', 'art 3', 'art 2', 'art 3', 'art 3', 'art 2', 'art 3', 'art 2', 'art 3', 'art 2', 'art 3', 'art 2', 'art 3', 'art 2', 'art 3', 'art 2', 'art 3', 'art 2', 'art 3', 'art 2', 'art 3']

Patent US7045768 - Displacement/quantity of light converter - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inAdvanced Patent SearchPatentsA 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...http://www.google.com/patents/US7045768?utm_source=gb-gplus-sharePatent US7045768 - Displacement/quantity of light converterAdvanced Patent SearchPublication numberUS7045768 B2Publication typeGrantApplication numberUS 10/467,002PCT numberPCT/JP2002/001423Publication dateMay 16, 2006Filing dateFeb 19, 2002Priority dateFeb 20, 2001Fee statusPaidAlso published asDE02712458T1, EP1371956A1, EP1371956A4, US20040090686, WO2002066939A1Publication number10467002, 467002, PCT/2002/1423, PCT/JP/2/001423, PCT/JP/2/01423, PCT/JP/2002/001423, PCT/JP/2002/01423, PCT/JP2/001423, PCT/JP2/01423, PCT/JP2001423, PCT/JP2002/001423, PCT/JP2002/01423, PCT/JP2002001423, PCT/JP200201423, PCT/JP201423, US 7045768 B2, US 7045768B2, US-B2-7045768, US7045768 B2, US7045768B2InventorsToru Shinzou, Yoshio SakamotoOriginal AssigneeKabushiki Kaisha KenwoodExport CitationBiBTeX, EndNote, RefManPatent Citations (7), Non-Patent Citations (1), Classifications (20), Legal Events (6) External Links: USPTO, USPTO Assignment, EspacenetDisplacement/quantity of light converterUS 7045768 B2Abstract 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.
TECHNICAL FIELD The present invention relates to a displacement/light-quantity converter that converts a mechanical vibration into a light signal. In particular, it relates to a displacement/light-quantity converter capable of converting a small mechanical displacement into a significant variation of light quantity.
BACKGROUND ART An example of a conventional displacement/light-quantity converter for converting a mechanical vibration into a light signal will be described with reference to FIGS. 4 and 5. In the converter shown in FIG. 4, a planar diaphragm 4 is opposed to a light emitting part 2 and a light receiving part 3 at substantially the same distance d from the parts. Diverging light emitted from the light emitting part 2 at a certain emission angle is reflected off the diaphragm 4, and some of the reflected light reaches the light receiving part 3. FIG. 5 illustrates a relationship between the distance d from the light emitting part 2 and the light receiving part 3 to the diaphragm 4 and the quantity of light impinging on the light receiving part 3 in FIG. 4. As shown in FIG. 5( a), if the distance d from the light emitting part 2 and the light receiving part 3 to the diaphragm 4 is d1, which is less than a predetermined distance, the light emitted from the light emitting part 2 at the certain emission angle and reflected off the diaphragm 4 does not impinge on the light receiving part 3. However, as shown in FIG. 5( b), if the distance d is d2, which is larger than d1, the light emitted from the light emitting part 2 at the certain emission angle and reflected off the diaphragm 4 impinges on an area of the light receiving surface of the light receiving part 3.
DISCLOSURE OF THE INVENTION The present invention has been devised in view of the above-described disadvantages of conventional devices. An object of the invention is to provide a displacement/light-quantity converter in which detection sensitivity of a diaphragm to a small displacement thereof due to an acoustic wave and the like is readily and surely improved.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows an entire configuration of a displacement/light-quantity converter according to an embodiment of this invention;
FIGS. 2( a)�(d) illustrate how light reflected off a diaphragm impinges on a light receiving part for variable distances from the diaphragm to a light emitting part and the light receiving part in the converter shown in FIG. 1;
FIGS. 5( a)�(d) illustrate how light reflected off a diaphragm impinges on a light receiving part for variable distances from the diaphragm to a light emitting part and the light receiving part in the converter shown in FIG. 4;
MODE FOR CARRYING OUT THE INVENTION In the following, a displacement/light-quantity converter according to an embodiment of the invention will be described with reference to the drawings. FIG. 1 shows an entire configuration of the displacement/light-quantity converter according to the embodiment of the invention. In this drawing, a light emitting part 2 and a light receiving part 3 are incorporated in a single package, and a concave diaphragm 1 is disposed at substantially the distance d from the parts facing its concave surface to the light emitting part 2 and the light receiving part 3. The concave surface of the diaphragm 1 is a rotational curved surface that is formed by rotating a curve R 360 degrees about a central axis X�X′, which passes through a central point P between the light emitting part 2 and the light receiving part 3 and is perpendicular to the diaphragm 1. The curve R is a part of a circle, the radius of curvature r of which circle corresponds with the line connecting the central point P between the light emitting part 2 and the light receiving part 3 to the diaphragm 1. Rotating this curve R 360 degrees about the central axis X�X′ provides a spherical surface, which is the rotational curved surface. Such a rotational curved surface allows the light emitted from the light emitting part 2 to be collected in the vicinity of the light receiving part 3.