Densitometer for measuring average aperture diameter

Claim 2

In an apparatus for producing a signal manifesting the average aperture diameter of an apertured member by the measurement of light transmission through said member, said apparatus including: a. means for producing a light beam, b. means for dividing said beam into a measuring beam and a reference beam, c. a reference photocell disposed to receive said reference beam for producing a reference signal sref, d. a measuring photocell disposed to receive said measuring beam passed through a plurality of said apertures in said member for producing a measuring signal tmeas manifesting the intensity of said passed measuring beam, the combination therewith comprising: means for providing a settable reference signal ka representing the spacing of said plurality of apertures, and signal processing means responsive to said reference signal sref, measuring signal tmeas and said settable reference signal ka applied as inputs thereto for providing as an output therefrom a signal hb manifesting the average diameter of said plurality of apertures in accordance with the relationship

Claim 3

The apparatus of claim 1 further including digital display means responsive to said output signal hb applied as an input thereto for producing a digital display of said average aperture diameter.

Claim 4

The apparatus of claim 1 wherein said signal processing means includes: means responsive to said reference signal sref and said measuring signal tmeas applied as inputs thereto for providing as an output therefrom a signal representing the logarithm of the ratio of one of said signals tmeas and sref to the other of said signals tmeas and sref, means responsive to said ratio signal applied as an input thereto for producing as an output therefrom a first signal representing said logarithm ratio signal divided by about two, means responsive to said settable reference signal ka applied as an input thereto for providing as an output therefrom a second signal representing the logarithm of said settable reference signal ka, means responsive to said first and second signals applied as inputs thereto for providing as an output therefrom a third signal representing the sum of said first and second signals, and means for taking the antilogarithm of said third signal applied as an input thereto to thereby produce said signal hb.

Claim 5

The apparatus of claim 3 further including display means responsive to said signal hb for providing a digital display of the magnitude of said average aperture diameter.

Claim 6

The apparatus of claim 3 wherein said reference and measuring photocells produce currents representing the magnitude of said reference signal sref and measuring signal tmeas, respectively, said apparatus further including means for converting said currents into respective voltages whose magnitudes represent the respective magnitudes of said signals sref and tmeas.

Claim 7

The apparatus of claim 5 wherein said converting means include respective corresponding operational amplifiers.

Claim 8

The apparatus of claim 3 wherein said first signal producing means includes settable voltage divider means.

Claim 9

The apparatus of claim 1 wherein said member is an aperture mask used in a color television picture tube.

Claim 10

The apparatus of claim 1 including securing means for securing said reference cell in fixed positional relationship with respect to the position of said light beam producing means.

Claim 11

The apparatus of claim 1 wherein said reference cell is exposed directly to said reference beam.

Claim 12

In combination: a light source, a first photocell arranged to receive light from said sOurce for producing an output signal in response to said received light manifesting the intensity of said received light, a second photocell arranged to receive a beam of light from said source for producing an output signal in response to said received beam manifesting the intensity of the light received thereby, means arranged for disposing an apertured member between said second photocell and said light source, the portion of said member intercepting said beam of light having a given area transverse said beam, the aperture in said member having a given area transverse said beam less than said portion area, means for providing a reference signal manifesting said portion given area, and signal processing means responsive to said first and second photocell output signals and said reference signal applied as inputs thereto for producing as an output signal therefrom a signal representing the diameter of said aperture, wherein the relationship of said processing means output signal to said photocell output signals and said reference signal is

Claim 13

In combination: a light source, a first photocell arranged to receive light from said sOurce for producing an output signal in response to said received light manifesting the intensity of said received light, a second photocell arranged to receive a beam of light from said source for producing an output signal in response to said received beam manifesting the intensity of the light received thereby, means arranged for disposing an apertured member between said second photocell and said light source, the portion of said member intercepting said beam of light having a given area transverse said beam, the aperture in said member having a given area transverse said beam less than said portion area, means for providing a reference signal manifesting said portion given area, and signal processing means responsive to said first and second photocell output signals and said reference signal applied as inputs thereto for producing as an output signal therefrom a signal representing the diameter of said aperture, wherein the relationship of said processing means output signal to said photocell output signals and said reference signal is

Claim 14

A densitometer for providing a measuring signal representing the value of the diameter of an aperture in a light opaque member comprising: means for taking the ratio of the intensity of a light beam received from a source to the intensity of a light beam received from said source transmitted through said aperture to produce as an output signal therefrom a signal representing said compared light intensities, means for providing a reference signal representing a given area of said member transverse said transmitted beam greater than the area of said aperture transverse said transmitted beam, means responsive to said output signal for producing a signal representing the square root of the value of said output signal, and multiplying means responsive to said square root produced signal and said reference signal applied as inputs thereto for multiplying said produced square root signal and said reference signal generating said measuring signal as an output therefrom.

Claim 15

A densitometer for providing a measuring signal representing the value of the diameter of an aperture in a light opaque member comprising: means for taking the ratio of the intensity of a light beam received from a source to the intensity of a light beam received from said source transmitted through said aperture to produce as an output signal therefrom a signal representing said compared light intensities, means for providing a reference signal representing a given area of said member transverse said transmitted beam greater than the area of said aperture transverse said transmitted beam, means responsive to said output signal for producing a signal representing the square root of the value of said output signal, and multiplying means responsive to said square root produced signal and said reference signal applied as inputs thereto for multiplying said produced square root signal and said reference signal generating said measuring signal as an output therefrom.

Claim 16

A densitometer comprising: means for comparing the intensity of a standard light beam to the intensity of said beam when transmitted through a plurality of apertures in an apertured member, said comparing means producing an output signal representing the relative intensity of said compared beams, means for providing a reference signal representing the spacing of adjacent apertures in said member, and means responsive to said compared light beam output signal and said reference signal applied as inputs thereto for providing as an output therefrom a signal whose magnitude is a function of the average diameter of said plurality of apertures in accordance with the relationship

Claim 17

A densitometer comprising: means for comparing the intensity of a standard light beam to the intensity of said beam when transmitted through a plurality of apertures in an apertured member, said comparing means producing an output signal representing the relative intensity of said compared beams, means for providing a reference signal representing the spacing of adjacent apertures in said member, and means responsive to said compared light beam output signal and said reference signal applied as inputs thereto for providing as an output therefrom a signal whose magnitude is a function of the average diameter of said plurality of apertures in accordance with the relationship