Games using tangible projectile – Billiards or pool – Ball
Reexamination Certificate
1999-06-17
2001-06-12
Gerrity, Stephen F. (Department: 3711)
Games using tangible projectile
Billiards or pool
Ball
C473S052000
Reexamination Certificate
active
06244970
ABSTRACT:
The present invention relates to billiard tables, generally, and more particularly to optical sensing devices used in the ball return mechanism of a billiard table to segregate a regular-sized, standard cue ball from object balls.
BACKGROUND OF THE INVENTION
A billiard table is widely used in a variety of games, such as eight ball, snooker, etc. In all of these games players commonly use a cue stick to hit a white cue ball, which in turn strikes a colored numbered ball, known as an object ball, which the players direct into the pockets of the billiard table. The cue ball and object balls are returned together in a standard billiard table but the cue ball and object balls are segregated via mechanical or magnetic means in the typical commercial table of the prior art.
In a commercial table, it is desirable to segregate the cue ball from the object balls so that the cue ball is returned to the players all times, while the object balls are being collected in a central location. In existing commercial tables, the cue ball is either larger than the object balls or the cue ball has a magnetic core to allow the cue ball to be physically segregated from the object balls. Both of these physical changes to the cue ball affect the play of the cue ball and therefore detract from the competitiveness of games.
By detecting the presence of a regular-sized, standard cue ball (without a magnetic core) within a standard set of object balls and then by sorting the cue ball from the object balls, the play of games would be significantly enhanced. In addition, the development of a regulation commercial table would be possible.
SUMMARY OF THE INVENTION
The present invention includes two optical techniques for selective detection of a regular-sized, standard cue ball. Both techniques make it possible to distinguish a regular-sized, standard size cue ball from object balls within a standard set. The first technique is called the “optical density discrimination” technique. It is based on the fact that the optical density of the cue ball is significantly less than the optical density of the object balls. The second technique is called the “fluorescence discrimination” technique. It requires that the cue ball be manufactured with a fluorescent pigment in its outer surface during manufacture. Discrimination is then based on detecting the fluorescence of the cue ball.
The “optical density discrimination” technique works as follows. An LED (either red or infrared) is modulated and pointed to illuminate a portion of the cue ball in such a way that all specular reflections are directed away from a detector. The detection system includes a detector, synchronous detection circuit, threshold, and npn output. The detector is positioned such that light from the LED must travel through at least a portion of the volume of the cue ball in order to reach the detector. The detector threshold is set such that a cue ball, with its lower optical density, produces a signal at the detector of sufficient strength to exceed a threshold and activate the npn output. All object balls, with their higher optical density, fail to activate the output. Modulation of the LED and synchronous detection ensures insensitivity to ambient light.
The “fluorescence discrimination” technique is similar to the optical density technique except that the wavelength of the light source is selected such that it excites the fluorescent material within the cue ball. The detector is filtered to detect only the fluorescence given off by the fluorescent material within the cue ball. In this way only the cue ball generates sufficient signal at the detector to cause activation of the output.
One embodiment of the present invention is an optical sensor for distinguishing a cue ball from an object ball, comprising a light emitting source with means to concentrate or limit its illumination to a portion of a cue ball; a detector responsive to the wavelength emitted by the light emitting source having means to limit the field of view of the detector to an area of the cue ball not directly illuminated by the light emitting source; means to produce an electrical current proportional to the detected light striking the detector; and means to generate an output signal from the sensor when detected light striking the detector generates an electrical current of a predetermined amplitude.
Another embodiment of the present invention is an optical sensor for distinguishing a cue ball having a fluorescent pigment therein from an object ball, comprising a light emitting source that emits excitation light of a wavelength that is absorbed by a fluorescent pigment within a cue ball and that generates fluorescent emission when the cue ball is illuminated thereby; a dichroic mirror positioned in the illumination path of the light emitting source with means to pass the excitation wavelengths and to reflect the fluorescent emission wavelengths to a focusing lens that focuses the fluorescent emission wavelengths through an optical filter to a detector that is responsive to fluorescent wavelengths; means to produce an electrical current proportional to the fluorescent wavelengths striking the detector; and means to generate an output signal from the sensor when fluorescent wavelengths striking the detector generate an electrical current of a predetermined amplitude.
Another embodiment of the present invention is a ball return mechanism for a billiard table having an optical sensor for distinguishing a cue ball from an object ball as in either embodiment set forth in the immediately foregoing paragraphs.
Another embodiment of the present invention is a billiard table having a ball return mechanism with an optical sensor for distinguishing a cue ball from an object ball as in either embodiment set forth in the immediately foregoing paragraphs.
It is therefore an object of the present invention to provide optical devices to be used in the ball return mechanism of a billiard table for optically detecting the presence of a regular-sized, standard cue ball as the cue ball and object balls pass through the ball return mechanism.
REFERENCES:
patent: 2825565 (1958-03-01), Hooker
patent: 4015845 (1977-04-01), Sines
patent: 4042491 (1977-08-01), Hazeltine et al.
patent: 5255916 (1993-10-01), Bleich
patent: 5846138 (1998-12-01), Borden et al.
patent: 2653349 (1997-04-01), None
Mersch Steven
Sullivan Robert G.
Aryanpour Mitra
Diamond Billiard Products, Inc.
Gerrity Stephen F.
Woodard Emhardt Naughton Moriarty & McNett
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