Radiation sensitive means for detecting flaws in glass

Claim 2

In apparatus of the type which detects flaws in glass having substantially planar surfaces, which flaws are, characteristically, either of a first, light-refracting type, or a second, light-scattering type, and which apparatus comprises: means for passing a beam of light from a source through said glass; and means for forming a pair of images of said glass intercepted by said beam, one image being formed to have a dark field and the other image being formed to have a light field, a flaw of the first type being effective to decrease the quantity of light in said other image and not to increase the quantity of light in said one image, a flaw of the second type being effective to decrease the quantity of light in said other image and to increase the quantity of light in said one image; the improvements which comprise means for directing said one image on a first photosensitive element, means for directing said other image on a second photosensitive element; and means for processing signals derived from said photosensitive elements to identify a flaw as to type, and including means effective to inhibit the signal provided by said second photosensitive element when images arising from a flaw of said second type are directed onto said photosensitive elements.

Claim 3

Apparatus according to claim 1, and characterized in that said means effective to inhibit the signal comprises control means operable in response to signals derived from said first photosensitive element effectively to block signals derived from said second photosensitive element, when signals are generated by said first photosensitive element.

Claim 4

Apparatus according to claim 2 and further characterized in that said control means comprises: switch means; means providing a connection between the output of said second photosensitive element and an output terminal; means providing a connection from the output of said first photosensitive element to said switch means to operate the latter, said switch means upon operation being effective to prevent signals from said second photosensitive element from reaching said output terminal whEn there are signals generated by both said first photosensitive element.

Claim 5

Apparatus according to claim 1, and characterized in that said last recited means comprises: means arranged to supply predetermined voltages at each of a first, second, and third terminal if the amplitude of an input pulse exceeds a predetrmined threshold; means arranged to supply predetermined voltage at a fourth terminal in correspondence with the slope of an input pulse with predetermined fixed limits; first, second, and third pairs of series connected inverters each pair connected to one of said first, second, and third terminals, respectively; a two-input NAND gate; first and second three-input NAND gates; means connecting the first input terminal of said two-input NAND gate to a first input terminal of said second three-input NAND gate and to the output terminal of said second pair of inverters; means connecting the second input terminal of said two-input NAND gate to the output terminal of said third pair of inverters and to the second input terminal of said second three-input NAND gate; means connecting the output terminal of said two-input NAND gate to the second input terminal of said first three-input NAND gate; means connecting the output terminal of said first pair of inverters to said first input terminal of said first NAND gate; and means connecting said fourth terminal to the third input terminals of each of said first and second three-input NAND gates.

Claim 6

Apparatus according to claim 4, and further characterized in that said two-input NAND gate in functioning as an inhibitor, is operable to produce a zero at its output terminal, when there is a one at each of its input terminals, and wherein an input voltage pulse arriving at said second and third terminals, as indications of a flaw of said second type, produce such a one at each input terminal of said two input NAND gate and as a result produce a zero at its output terminal, so that said first three-input NAND gate is prevented from operating to produce a zero at its output as a false indication of a defect of said first type.

Claim 7

Apparatus according to claim 5, and characterized further by the provision for connection to the output terminals of said first and second three-input NAND gates means operable to mark said glass in the region of a detected flaw, in response to a pulse received at a corresponding, last recited, output terminal.

Claim 8

Apparatus according to claim 4 wherein said last recited means as characterized therein further comprises: means arranged to supply predetermined voltages at each of a fifth, sixth, and seventh terminal if the amplitude of an input pulse to each exceeds a predetermined threshold; fourth, fifth and sixth pairs of series connected inverters, each pair connected to one of said fifth, sixth, and seventh terminals, respectively; a second two-input NAND gate; first and second four-input NAND gates; means connecting a first input terminal of said first four-input NAND gate to the output terminal of said fourth pair of series connected inverters; means connecting a second input terminal of said first four-input NAND gate to the output terminal of the first inverter of said first pair of series connected inverters; means connecting a third input terminal of said first four-input NAND gate to the output of said second NAND gate; means connecting the output terminal of said first two-input NAND gate to the first input terminal of said second four-input NAND gate; means connecting the first input terminal of said second two-input NAND gate to the second input terminal of said second four-input NAND gate; means connecting the third input terminal of said second four-input NAND gate to the second input terminal of said second two-input NAND gate; means connecting the fourth input terminals of each of said first and second four-input gates to said fourth terminal; means connecting thee output terminal of said fifth pair of inverters to the first input terMinal of said second two-input NAND gate; and means connecting the output terminal of said sixth pair of inverters to the second input terminal of said second two-input NAND gate.

Claim 9

Improved apparatus for detecting defects in glass having substantially planar surfaces, which defects are of a pair of types characterized generally as bubbles and viscous lumps, the former tending to refract and the latter tending to scatter transmitted light, which improved apparatus comprises: a source of light; lens means for focusing light from said source onto said glass; stop means interposed between said source of light and said lens means for partially stopping said lens means to outgoing light; first reflective means positioned closely adjacent the plane of the principal focus of said lens means for reflecting the light pattern established by said stop means onto said lens means in substantially one-to-one area correspondence; first photosensitive means; means for transmitting portions of the reflected light pattern passing through stopped regions of said lens means to said first photosensitive means; second photosensitive means; partially light transmissive light reflective means positioned between said lens means and its point of focus and effective to transmit light and to direct unstopped portions of the reflected light pattern onto said second photosensitive means, interruption of the focused beam of light by a bubble defect being effective to defocus the beam and to increase the divergence of the return beam so that a light loss occurs at said second photosensitive means, with no increase in light at the first photosensitive means, and interruption of the focussed beam of light by a viscous lump defect being effective to scatter the return beam so that there is a loss of light at the second photosensitive means and an increase in light at the first photosensitive means; and said improved apparatus being characterized by the inclusion of means for processing signals derived from said first and second photosensitive means to identify a defect as to type, said means for processing comprising means effective to inhibit the signal derived from said second photosensitive means when said focused beam is scattered upon encountering a viscous lump defect, whereby to ensure derivation of a signal only from said first photosensitive means indicative of a viscous lump defect.

Claim 10

Improved apparatus for detecting defects in glass having substantially planar surfaces, which defects are of a pair of types characterized generally as bubbles and viscous lumps, the former tending to refract and the latter tending to scatter transmitted light, which improved apparatus comprises: a source of light; lens means for focusing light from said source onto said glass; stop means interposed between said source of light and said lens means for partially stopping said lens means to outgoing light; first reflective means positioned closely adjacent the plane of the principal focus of said lens means for reflecting the light pattern established by said stop means onto said lens means in substantially one-to-one area correspondence; first photosensitive means; means for transmitting portions of the reflected light pattern passing through stopped regions of said lens means to said first photosensitive means; second photosensitive means; partially light transmissive light reflective means positioned between said lens means and its point of focus and effective to transmit light and to direct unstopped portions of the reflected light pattern onto said second photosensitive means, interruption of the focused beam of light by a bubble defect being effective to defocus the beam and to increase the divergence of the return beam so that a light loss occurs at said second photosensitive means, with no increase in light at the first photosensitive means, and interruption of the focussed beam of light by a viscous lump defect being effective to scatter the return beam so that there is a loss of light at the second photosensitive means and an increase in light at the first photosensitive means; and said improved apparatus being characterized by the inclusion of means for processing signals derived from said first and second photosensitive means to identify a defect as to type, said means for processing comprising means effective to inhibit the signal derived from said second photosensitive means when said focused beam is scattered upon encountering a viscous lump defect, whereby to ensure derivation of a signal only from said first photosensitive means indicative of a viscous lump defect.

Claim 11

In apparatus of the type which detects flaws in glass having substantially planar surfaces, which flaws are characteristically of a first, light refracting type, or of a second, light scattering type, and which apparatus comprises: means for directing a beam of light from a source through said glass; and means for forming images of said glass intercepted by said beam, one image being formed to have a dark field and the other image being formed to have a light field, the presence of a flaw of the light refracting type being effective to decrease the quantity of light in said other image and not to increase the quantity of light in said one image, a flaw of the light scattering type being effective to decrease the quantity of light in said other image and to increase the quantity of light in said one image; the improvements which comprise first and second photosensitive elements, means for directing said one image on said first photosensitive element, means for directing said other image on a second photosensitive element, and means for inhibiting the signal derived at said second photosensitive element arising when an image is received thereon due to the presence of a flaw of the light scattering type, whereby a signal indicative of a flaw of the light refractive type is prevented when a flaw of a light scattering type is present.

Claim 12

In apparatus of the type which detects flaws in glass having substantially planar surfaces, which flaws are characteristically of a first, light refracting type, or of a second, light scattering type, and which apparatus comprises: means for directing a beam of light from a source through said glass; and means for forming images of said glass intercepted by said beam, one image being formed to have a dark field and the other image being formed to have a light field, the presence of a flaw of the light refracting type being effective to decrease the quantity of light in said other image and not to increase the quantity of light in said one image, a flaw of the light scattering type being effective to decrease the quantity of light in said other image and to increase the quantity of light in said one image; the improvements which comprise first and second photosensitive elements, means for directing said one image on said first photosensitive element, means for directing said other image on a second photosensitive element, and means for inhibiting the signal derived at said second photosensitive element arising when an image is received thereon due to the presence of a flaw of the light scattering type, whereby a signal indicative of a flaw of the light refractive type is prevented when a flaw of a light scattering type is present.