Optical distance converter

Claim 2

Apparatus for measuring the thickness of a transparent body comprising: optical guide means for transmitting light from a terminal portion thereof for reflection by a front face and a rear face of a transparent body having said front face opposite said terminal portion and at a frontal distance therefrom, the thickness of the body being represented by the distance between these faces; first and second optical guide receiver means each having a receiving and an output end for transmitting a corresponding flux of the light reflected by the transparent body from such receiving end to such output end, the receiving ends of said first and second receiver means being disposed with respect to said terminal portion to obtain first and second relationships between the corresponding light fluxes and the distance from said terminal portion to a corresponding one of the front and rear faces of the transparent body which are substantially linear over a frontal distance range and a body thickness range; means for converting the light fluxes corresponding to said first and second receiving means into respective first and second signals varying linearly with the distance from said terminal portion to said front and rear faces respectively with substantially the same rate of variation within the frontal distance range and the body thickness range; and means coupled to said signal converting means for producing a third signal functionally related to the difference between the magnitudes of said first and second signals which is representative of body thickness over the frontal distance range and the thickness range.

Claim 3

The apparatus of claim 1 wherein said signal converting means includes respective detector means responsive to the corresponding light fluxes for producing representative electrical signals and means for selectively amplifying each said representative electrical signal to produce said first and second signals having the same rate of linear variation.

Claim 4

Apparatus for measuring the thickness of a transparent body having front and rear faces, comprising: means including a light transmitting guide for transmitting light from an emitting end portion thereof for reflection by the front and rear faces of the transparent body, the emitting end portion positioned opposite the front face at a frontal distance therefrom, the thickness of the body being represented by the distance between said faces, first means for converting a first flux of the light reflected by the front face of the body into a first electrical signal and second means for converting a second flux of the light reflected by the rear face of the body into a second electrical signal, said first converting means including a first light receiving guide having a first receiving end disposed with respect to said emitting end portion for picking up at least said first light flux and first photodetecting means responsive to said first light flux for producing said first electrical signal, and said second converting means including a second light receiving guide having a second receiving end disposed with respect to said emitting end portion for picking up at least said second light flux and second photodetecting means responsive to said second light flux for producing said second electrical signal, said first and second receiving ends defining respective first and second elementary probe heads with said emitting end portion, the relationships beTween the magnitudes of said first and second electrical signals and the distance from the emitting end portion to the respective one of said front and rear light reflecting faces being represented by first and second characteristic curves respectively, each said curve having distance as one coordinate thereof and electrical signal magnitudes as the other coordinate thereof and being characterized by, a non-linear section having an origin at the distance coordinate for a substantially null value of said electrical signal magnitude, the position of the origin of the respective curve with respect to the origin of said distance coordinate being determined by the position of the respective one of said first and second receiving ends relative to said emitting end portion, a peak section having a maximum valve essentially determined by the cross-sectional area of said emitting end portion, the ratio of the cross-sectional area of the respective one of said first and second receiving ends to the cross-sectional area of the corresponding one of said first and second elementary probe heads, and the gain of the respective one of said first and second photodetecting means, said curves being further characterized by a substantially linear section joining said non-linear section and said peak section over a working range along the distance coordinate and having a range width determined by the transverse dimension of the respective one of said first and second receiving ends, a mid-range point at a distance along said distance coordinate which is determined by the relative positions of said emitting end portion and the respective one of said first and second receiving ends, and a slope determined by the maximum amplitude of said peak section, the linear section of said first curve extending over a frontal distance range between said emitting end portion and the front face of the transparent body, and the linear section of said second curve extending over a rear distance range defined by this frontal distance range and a range of thickness variations of said transparent body, and the slopes of the linear sections of said first and second curves being substantially equal, whereby said first electrical signal varies linearly with distance between said emitting end portion and the front face at the same rate than the rate of linear variation of said second electrical signal with distance between said emitting end portion and the rear face of the body, over said frontal distance and thickness ranges; and means coupled to said first and second detecting means for combining said first and second electrical signals to produce a third signal functionally related to the difference in magnitude between said first and second electrical signals which is representative of thickness of the transparent body.

Claim 5

Apparatus for measuring the thickness of a transparent body having front and rear faces, comprising: means including a light transmitting guide for transmitting light from an emitting end portion thereof for reflection by the front and rear faces of the transparent body, the emitting end portion positioned opposite the front face at a frontal distance therefrom, the thickness of the body being represented by the distance between said faces, first means for converting a first flux of the light reflected by the front face of the body into a first electrical signal and second means for converting a second flux of the light reflected by the rear face of the body into a second electrical signal, said first converting means including a first light receiving guide having a first receiving end disposed with respect to said emitting end portion for picking up at least said first light flux and first photodetecting means responsive to said first light flux for producing said first electrical signal, and said second converting means including a second light receiving guide having a second receiving end disposed with respect to said emitting end portion for picking up at least said second light flux and second photodetecting means responsive to said second light flux for producing said second electrical signal, said first and second receiving ends defining respective first and second elementary probe heads with said emitting end portion, the relationships beTween the magnitudes of said first and second electrical signals and the distance from the emitting end portion to the respective one of said front and rear light reflecting faces being represented by first and second characteristic curves respectively, each said curve having distance as one coordinate thereof and electrical signal magnitudes as the other coordinate thereof and being characterized by, a non-linear section having an origin at the distance coordinate for a substantially null value of said electrical signal magnitude, the position of the origin of the respective curve with respect to the origin of said distance coordinate being determined by the position of the respective one of said first and second receiving ends relative to said emitting end portion, a peak section having a maximum valve essentially determined by the cross-sectional area of said emitting end portion, the ratio of the cross-sectional area of the respective one of said first and second receiving ends to the cross-sectional area of the corresponding one of said first and second elementary probe heads, and the gain of the respective one of said first and second photodetecting means, said curves being further characterized by a substantially linear section joining said non-linear section and said peak section over a working range along the distance coordinate and having a range width determined by the transverse dimension of the respective one of said first and second receiving ends, a mid-range point at a distance along said distance coordinate which is determined by the relative positions of said emitting end portion and the respective one of said first and second receiving ends, and a slope determined by the maximum amplitude of said peak section, the linear section of said first curve extending over a frontal distance range between said emitting end portion and the front face of the transparent body, and the linear section of said second curve extending over a rear distance range defined by this frontal distance range and a range of thickness variations of said transparent body, and the slopes of the linear sections of said first and second curves being substantially equal, whereby said first electrical signal varies linearly with distance between said emitting end portion and the front face at the same rate than the rate of linear variation of said second electrical signal with distance between said emitting end portion and the rear face of the body, over said frontal distance and thickness ranges; and means coupled to said first and second detecting means for combining said first and second electrical signals to produce a third signal functionally related to the difference in magnitude between said first and second electrical signals which is representative of thickness of the transparent body.

Claim 6

The apparatus of claim 3 wherein said combining means includes a differential amplifier having first and second inputs responsive to said first and second electrical signals respectively.

Claim 7

Apparatus for measuring thickness within a range of a transparent body having front and rear faces, comprising: light transmitting means including a fiber optics bundle for transmitting light from an emitting end portion thereof for reflection by the front and rear faces of the transparent body, the emitting end portion positioned opposite the front face within a frontal distance range therefrom, the thickness of the body being represented by the distance between said front and rear faces; a first light receiving fiber optics bundle having a first output and first receiving end located at a first transverse spacing from said emitting end portion for picking up a first flux of the light reflected by the front face of the transparent body; first photodetecting means at said first output responsive to said first light flux for producing a first electrical signal; a second light receiving fiber optics bundle having a second output and a second receiving end locateD at a second transverse spacing from said emitting end portion, said second spacing being greater than said first spacing, for picking up a second flux of the light reflected by the rear face of the transparent body; second photodetecting means at said second output responsive to said second light flux for producing a second electrical signal; said first and second receiving ends defining respective first and second elementary probe heads with said emitting end portion, and the relationships between the magnitudes of said first and second electrical signals and the distance from the emitting end portion to the respective one of said front and rear light reflecting faces being represented by first and second characteristic curves respectively, each said curve having distance as one coordinate thereof and the respective electrical signal magnitude as the other coordinate thereof, and being characterized by, a non-linear section having an origin at the distance coordinate for a substantially null value of said electrical signal magnitude, the position of the origin of the respective curve with respect to the origin of said distance coordinate being determined by the respective one of said first and second spacings, a peak section having a maximum value essentially determined by, the cross-sectional area of said emitting end portion, the ratio of the cross-sectional area of the respective one of said first and second receiving ends to the cross-sectional area of the corresponding one of said first and second elementary probe heads, and the gain of the respective one of said first and second photodetecting means, said curves being further characterized by a substantially linear section joining said non-linear section and said peak section over a range along the distance coordinate and having a range width determined by the transverse dimension of the respective one of said first and second receiving ends, a mid-range point at a distance along said distance coordinate which is determined by the respective one of said first and second spacings, and a slope determined by the maximum amplitude of said peak section, said first receiving end having a transverse dimension defining a working range width for said first curve substantially equal to the width of the frontal distance range, the gains of said first and second photodetecting means being adjusted to different values selected to establish a substantially equal slopes for the linear sections of said first and second curves, and the difference between said second and first spacings determining a displacement between the mid-working range points of said first and second curves equal to the mid-range value of the thickness range; and differential amplifier means having first and second outputs responsive to said first and second electrical signals respectively for producing a signal representative of the thickness of a transparent body within the ranges of thickness and of frontal distances between said emitting end portion and the front face of the transparent body.

Claim 8

Apparatus for measuring thickness within a range of a transparent body having front and rear faces, comprising: light transmitting means including a fiber optics bundle for transmitting light from an emitting end portion thereof for reflection by the front and rear faces of the transparent body, the emitting end portion positioned opposite the front face within a frontal distance range therefrom, the thickness of the body being represented by the distance between said front and rear faces; a first light receiving fiber optics bundle having a first output and first receiving end located at a first transverse spacing from said emitting end portion for picking up a first flux of the light reflected by the front face of the transparent body; first photodetecting means at said first output responsive to said first light flux for producing a first electrical signal; a second light receiving fiber optics bundle having a second output and a second receiving end locateD at a second transverse spacing from said emitting end portion, said second spacing being greater than said first spacing, for picking up a second flux of the light reflected by the rear face of the transparent body; second photodetecting means at said second output responsive to said second light flux for producing a second electrical signal; said first and second receiving ends defining respective first and second elementary probe heads with said emitting end portion, and the relationships between the magnitudes of said first and second electrical signals and the distance from the emitting end portion to the respective one of said front and rear light reflecting faces being represented by first and second characteristic curves respectively, each said curve having distance as one coordinate thereof and the respective electrical signal magnitude as the other coordinate thereof, and being characterized by, a non-linear section having an origin at the distance coordinate for a substantially null value of said electrical signal magnitude, the position of the origin of the respective curve with respect to the origin of said distance coordinate being determined by the respective one of said first and second spacings, a peak section having a maximum value essentially determined by, the cross-sectional area of said emitting end portion, the ratio of the cross-sectional area of the respective one of said first and second receiving ends to the cross-sectional area of the corresponding one of said first and second elementary probe heads, and the gain of the respective one of said first and second photodetecting means, said curves being further characterized by a substantially linear section joining said non-linear section and said peak section over a range along the distance coordinate and having a range width determined by the transverse dimension of the respective one of said first and second receiving ends, a mid-range point at a distance along said distance coordinate which is determined by the respective one of said first and second spacings, and a slope determined by the maximum amplitude of said peak section, said first receiving end having a transverse dimension defining a working range width for said first curve substantially equal to the width of the frontal distance range, the gains of said first and second photodetecting means being adjusted to different values selected to establish a substantially equal slopes for the linear sections of said first and second curves, and the difference between said second and first spacings determining a displacement between the mid-working range points of said first and second curves equal to the mid-range value of the thickness range; and differential amplifier means having first and second outputs responsive to said first and second electrical signals respectively for producing a signal representative of the thickness of a transparent body within the ranges of thickness and of frontal distances between said emitting end portion and the front face of the transparent body.

Claim 9

Apparatus for producing at least one signal varying linearly as a function of the distance in the normal direction from a reference face of the apparatus of a light reflecting surface, comprising: light transmitting means including a light transmitting guide having an emitting end portion at the reference face for transmitting light to a surface so as to be reflected by the surface; means for converting first and second fluxes of the light reflected by the surface into respective first and second output signals whose respective magnitudes vary differently in relation to the distance between the emitting end portion and the light reflecting surface, said converting means including first and second light receiving guides having first and second receiving ends located with respect to said emitting end portion at first and second transverse spacings therefrom for picking up said first and second light fluxes rEspectively, said first and second receiving ends having respective first and second transverse dimensions and defining respective first and second elementary probe heads with said emitting end, the relationships between the magnitude of said first and second output signals and the distance from the emitting end portion to the light reflecting surface being represented by first and second characteristic curves respectively, each said curve having distance as one coordinate thereof and being characterized by, a non-linear section having an origin at the distance coordinate for a substantially null value of said output signal magnitude, said first and second transverse spacings determining the position of the origin of the respective curve with respect to the origin of said distance coordinate, a peak section having a maximum value essentially determined by the cross-sectional area of said emitting end portion, the ratio of the cross-sectional area of the respective one of said first and second receiving ends to the cross-sectional area of the corresponding one of said first and second elementary probe heads, and gain of said converting means with respect to the corresponding one of said first and second output signals, said curves being further characterized by a substantially linear section joining said non-linear section and said peak section over a working range along the distance coordinate and having a range width determined by the transverse dimension of the respective one of said first and second receiving ends, a mid-range point at a distance along said distance coordinate which is determined by the transverse spacing between said emitting end portion and the respective one of said first and second receiving ends, and a slope determined by the maximum amplitude of said peak section, the gains of said converting means with respect to said first and second output signals being adjusted to define linear curve sections of equal slopes and peak sections of substantially equal maximum amplitudes for said first and second characteristic curves, whereby said curves have substantially identical shapes, said second transverse spacing being greater than said first transverse spacing but smaller than the sum of said first transverse spacing and said first transverse dimension, whereby said substantially identical curves are displaced with respect to one another along the distance coordinate, with the origin of said second curve falling between the origin of said first curve and the distance coordinate of the maximum peak value thereof, and the relative values of said spacings and transverse dimensions being further selected so that the working ranges of said first and second ranges have at least one point in common along the distance coordinate whereby the apparatus has an extended linear working range.

Claim 10

Apparatus for producing at least one signal varying linearly as a function of the distance in the normal direction from a reference face of the apparatus of a light reflecting surface, comprising: light transmitting means including a light transmitting guide having an emitting end portion at the reference face for transmitting light to a surface so as to be reflected by the surface; means for converting first and second fluxes of the light reflected by the surface into respective first and second output signals whose respective magnitudes vary differently in relation to the distance between the emitting end portion and the light reflecting surface, said converting means including first and second light receiving guides having first and second receiving ends located with respect to said emitting end portion at first and second transverse spacings therefrom for picking up said first and second light fluxes rEspectively, said first and second receiving ends having respective first and second transverse dimensions and defining respective first and second elementary probe heads with said emitting end, the relationships between the magnitude of said first and second output signals and the distance from the emitting end portion to the light reflecting surface being represented by first and second characteristic curves respectively, each said curve having distance as one coordinate thereof and being characterized by, a non-linear section having an origin at the distance coordinate for a substantially null value of said output signal magnitude, said first and second transverse spacings determining the position of the origin of the respective curve with respect to the origin of said distance coordinate, a peak section having a maximum value essentially determined by the cross-sectional area of said emitting end portion, the ratio of the cross-sectional area of the respective one of said first and second receiving ends to the cross-sectional area of the corresponding one of said first and second elementary probe heads, and gain of said converting means with respect to the corresponding one of said first and second output signals, said curves being further characterized by a substantially linear section joining said non-linear section and said peak section over a working range along the distance coordinate and having a range width determined by the transverse dimension of the respective one of said first and second receiving ends, a mid-range point at a distance along said distance coordinate which is determined by the transverse spacing between said emitting end portion and the respective one of said first and second receiving ends, and a slope determined by the maximum amplitude of said peak section, the gains of said converting means with respect to said first and second output signals being adjusted to define linear curve sections of equal slopes and peak sections of substantially equal maximum amplitudes for said first and second characteristic curves, whereby said curves have substantially identical shapes, said second transverse spacing being greater than said first transverse spacing but smaller than the sum of said first transverse spacing and said first transverse dimension, whereby said substantially identical curves are displaced with respect to one another along the distance coordinate, with the origin of said second curve falling between the origin of said first curve and the distance coordinate of the maximum peak value thereof, and the relative values of said spacings and transverse dimensions being further selected so that the working ranges of said first and second ranges have at least one point in common along the distance coordinate whereby the apparatus has an extended linear working range.

Claim 11

The apparatus of claim 6 comprising a third receiving light guide having a third receiving end having substantially the same transverse dimension as said first receiving end and juxtaposed thereto opposite to said emitting end.