Optical sample characterization

Abstract

To provide a device that facilitates measurement and testing at any angle in a full range of angles of light propagation through an optical sample, such as a coated glass plate, having a higher index of refraction than an air index of refraction.SOLUTION: A rotatable assembly includes a cylinder 1100 having a hollow 1111, and a receptacle 1110 including the hollow. The receptacle also contains a fluid 112 with a known refractive index. An optical light beam 420 is input normal to the surface of the cylinder, travels through the cylinder, then via the fluid, to an optical sample 102, where light beam is transmitted and / or reflected, then exits the cylinder and is collected for analysis. Due at least in part to the fluid surrounding the optical sample, the optical sample can be rotated through a full range of angles (±90°, etc.) for full range testing of the optical sample.SELECTED DRAWING: Figure 14A

Description

[Technical Field]

[0001] The present invention relates generally to optical testing, and more particularly to testing a full range of coatings. [Background technology]

[0002] Current techniques for measuring optical components, especially coatings, are limited to a small range of angles, or a small set of discrete angles, and / or have significant problems due to refraction. Measurement results generally lack consistency and / or accuracy. Summary of the Invention

[0003] Characterization of optical samples facilitates measurement and testing at any angle over the full range of light propagation through an optical sample, such as a coated glass plate with a refractive index higher than that of air. The rotatable assembly includes a cylinder having a hollow center and a receptacle containing the hollow center. The receptacle also contains a fluid with a refractive index matching that of the optical sample and / or the cylinder, in some implementations. An optical light beam is input perpendicular to the surface of the cylinder, travels through the cylinder and then through the fluid to the optical sample, where the light beam is transmitted and / or reflected, then exits the cylinder and collected for analysis. With the fluid at least partially surrounding the optical sample, the optical sample can be rotated over a full range of angles (such as ±90°) for testing the full range of the optical sample.

[0004] According to the teachings of this embodiment, an apparatus for optical testing of a sample of optical material is provided, the apparatus comprising: a rotatable assembly including: an optically transparent general cylinder having a central hollow on an axis of the general cylinder, the hollow being sized to receive at least a core region of the sample of optical material; and a receptacle containing the hollow, the receptacle being sized to receive at least a portion of the sample of optical material, the receptacle being sealed to receive a quantity of fluid such that the fluid surrounds and contacts at least the core region and is in contact with the general cylinder; a turntable aligned with the axis and operable to rotate the rotatable assembly about a height axis of the general cylinder; and an optical arrangement aligned with the axis and including a light source providing an optical light beam perpendicular to a surface region on a first side of the general cylinder; and an optical detector receiving an output signal, the output signal including a reflection of the optical light beam from the surface region, the optical detector being perpendicular to the surface region of the first side of the general cylinder.

[0005] According to the teachings of this embodiment, an apparatus for optical testing of a sample of optical material is provided, the apparatus comprising: an assembly including an optically transparent general cylinder, the interior of which is partially filled with a bulk material portion from an inner surface of the general cylinder toward a central axis of the general cylinder, the interior of which has a hollow portion extending from the inner surface of the opposite side of the general cylinder and including the axis, the hollow being sized to receive at least a core region of the sample of optical material; and a receptacle including the hollow, the receptacle being sized to receive at least a portion of the sample of optical material, the receptacle being sealed to receive a quantity of fluid such that the fluid surrounds and contacts at least the core region and contacts at least a portion of the general cylinder and the bulk; and an optical arrangement including a light source aligned with the axis and providing an optical light beam perpendicular to a surface region of a first side of the general cylinder, and an optical detector receiving an output signal, wherein the output signal from the optical light beam impinges on the core region and the optical detector is perpendicular to the surface region of the general cylinder.

[0006] In an optional embodiment, the assembly is a rotatable assembly and further includes a turntable aligned with the axis and operable to rotate the rotatable assembly about a common cylinder height axis.

[0007] In another optional embodiment, the bulk fills substantially half of the semicircular shape of the receptacle.

[0008] In another optional embodiment, the bulk material is the same optically transparent material as the optically transparent material of the general cylinder.

[0009] In another optional embodiment, the optical arrangement further includes a mounting arrangement for receiving the optical arrangement, the mounting arrangement being adjustable to align the light source and the optical detector.

[0010] In another optional embodiment, the sample holder further includes a clamping mechanism to fix the location of the sample relative to the receptacle.

[0011] In another optional embodiment, the device further includes a motor operably connected to the rotatable assembly and operable to rotate the rotatable assembly, and an encoder operably connected to the rotatable assembly and operable to provide position information related to at least an angle of rotation of the rotatable assembly.

[0012] In another optional embodiment, the general cylinder is selected from the group consisting of a cylinder and a prism. In another optional embodiment, the refractive indices of the general cylinder, the sample, and the fluid are substantially equal. In another optional embodiment, the fluid is an index-matching fluid, and the refractive indices of the sample and the fluid are substantially equal. In another optional embodiment, the general cylinder and the sample of optical material are made of the same optically transparent solid material.

[0013] In another optional embodiment, the general cylinder is substantially symmetrical parallel to the height axis of the general cylinder. In another optional embodiment, the general cylinder is positioned according to the group consisting of: stationary, rotatable about a single axis, rotatable about two or more axes, rotatable through a range of angles, and rotatable ±90 degrees from normal to the sample.

[0014] In another optional embodiment, the core region of the sample is the location on the sample where the light beam encounters the sample and where testing of the sample is performed.

[0015] In another optional embodiment, the receptacle has a receptacle width along a cylinder diameter of the general cylinder that is smaller than the cylinder diameter, and a receptacle thickness non-parallel to the receptacle width and between the first and second sides of the general cylinder, and the sample has a plate width along the cylinder diameter that is larger than the plate width, and a plate thickness non-parallel to the plate width and the receptacle thickness is larger than the plate thickness.

[0016] In another optional embodiment, the receptacle width and the plate width are aligned substantially parallel. In another optional embodiment, the receptacle is configured to contain between 0.5 cubic centimeters (cc) and 50 cc of fluid.

[0017] In another optional embodiment, the sample is selected from the group consisting of a glass plate, a coated glass plate, a thin film polarizer, a glass polarizer, a plastic polarizer, a beam splitter, a wave plate, a light guide optical element (LOE), a structured optical element selected from the group consisting of a regular grating, a holographic grating, a holographic volume grating, a diffractive optical element, a Fresnel lens, a sub-wavelength photonic structure, and a wire grid.

[0018] In another optional embodiment, the optical element is coated with a coating, which is used to manipulate the light incident on the sample.

[0019] In another optional embodiment, the optical arrangement includes a collimating optic that prepares an optical light beam and inputs the optical light beam into a general cylinder, the collimating optic being adjustable in at least two degrees of freedom. In another optional embodiment, an optical path of the optical light beam passes through the general cylinder and the fluid, and a majority of the optical path passes through the general cylinder.

[0020] In an optional embodiment, a controller operably connected to the apparatus of claim 1 or claim 3 is provided, the controller being configured to initiate input of an optical light beam perpendicular to a surface area of ​​a first side of the general cylinder, traverse through the first side of the general cylinder until the light beam path reaches the hollow, then traverse from the first side into the hollow fluid on the first side of the sample, through the sample, through the fluid on the other side of the sample, enter a second side of the general cylinder, traverse the second side and exit perpendicular to the surface area of ​​the second side of the general cylinder as an output signal, and activate capture of the output signal by an optical detector. In another optional embodiment, the controller is further configured to, after positioning the general cylinder at a first angle of the light beam path of the sample with respect to the light beam path, rotate the general cylinder so that the sample is at a second angle with respect to the light beam path, and repeat the capture and rotation.

[0021] According to the teachings of this embodiment, a method for optically testing a sample of optical material is provided, the method including the steps of providing an apparatus, inputting an optical light beam perpendicular to the surface area of ​​a first side of a general cylinder, positioning the general cylinder, and positioning the general cylinder so that the light beam path traverses through the first side of the general cylinder until it reaches the hollow, then from the first side into the hollow fluid on the first side of the sample, through the sample, through the fluid on the other side of the sample, enters the second side of the general cylinder, traverses the second side, and exits perpendicular to the surface area of ​​the second side of the general cylinder as an output signal, and capturing the output signal with an optical detector.

[0022] In another optional embodiment, the method further includes, after positioning the sample at a first angle relative to the optical beam path, rotating the general cylinder so that the sample is at a second angle relative to the optical beam path, and repeating the capturing and rotating. In another optional embodiment, the method further includes processing the data collected by the capturing to calculate results of the optical test. [Brief explanation of the drawings]

[0023] Embodiments are herein described, by way of example only, with reference to the accompanying drawings. [Figure 1A] 1 is a sketch of an apparatus for full range optical sample characterization (testing). [Figure 1B] 1 is a sketch of a cross section of the device. [Figure 2] 1 is a sketch of a top view of a cylinder. [Figure 3] 1 is a sketch of a side view of a cylinder. [Figure 4] 1 is a sketch of a top view of the cylinder on which the coated plate is rotated during testing. [Figure 5A] 1 is a sketch of a bath jig apparatus for testing the transmittance of optical samples. [Figure 5B] 1 is a sketch of a cross section of a bass jig device. [Figure 6A] 1 is a flowchart of a method for characterizing an optical sample. [Figure 7A] 1 is a plot of transmittance (y-axis) versus angle (x-axis). [Figure 7B] 7B is a close-up (zoomed-in) of the transmittance plot of FIG. 7A. [Figure 8] FIG. 2 is a high-level partial block diagram of an exemplary controller. [Figure 9] 1 is a sketch of an apparatus for full range optical sample characterization (testing). [Figure 10] 1 is a sketch of an exploded view of an MPL device. [Figure 11A] 1 is a sketch of a cross section of an MPL test device. [Figure 11B] FIG. 1 is a rotational cross-sectional view of the MPL testing device. [Figure 12] 1 is a sketch of an MPL test fixture including a variable positioning mechanism. [Figure 13] 1 is a sketch of a cross section of an MPL cylinder for plate testing. [Figure 14A] 10 is a cross-sectional sketch of an alternative implementation of the MPL cylinder. [Figure 14B] 10 is a cross-sectional sketch of an alternative embodiment implementation of the MPL cylinder. [Figure 14C] 10 is a cross-sectional sketch of an alternative implementation of the MPL cylinder. [Figure 15] 1 is a sketch of an alternative embodiment of the MPL cylinder.

[0024] Detailed Description - Apparatus - Figures 1A to 4 The principles and operation of the apparatus and method according to the present embodiments may be better understood with reference to the drawings and accompanying description. The present invention is an apparatus and method for characterizing optical samples. The present invention facilitates measurement and testing of a full range of angles of propagation of light through optical samples, such as coated glass plates, that have a refractive index higher than that of air.

[0025] In general, the innovative rotatable assembly includes a glass cylinder with a hollow center. The hollow center is part of a receptacle within the rotatable assembly. The receptacle is sized for coated glass plates of varying sizes. The receptacle is also sealed to receive a volume of fluid with a specific refractive index. A light beam propagates from a test source through collimating optics, enters perpendicular (90 degrees) to the surface of the cylinder, passes through the cylinder, and then passes through the coating, the (coated) glass plate, the fluid, and the fluid through the other side of the cylinder, where it is collected for analysis. With the fluid surrounding the at least partially coated plate, the plate can be rotated through a full range of angles (such as ±90°) for any particular angle in testing the full range of the coating. Preferably, the cylinder and plate are made of the same material so that their refractive indices are matched. An exemplary material is BK7 glass, but this example is not limiting; other glasses and materials other than glass can be tested. This apparatus and method can also be used to directly measure the reflectance of coated plates.

[0026] Current devices and methods are inadequate for characterizing current and predicted coatings over the full range of angles of incidence on glass. Conventional techniques are inadequate to meet existing requirements. Techniques are needed to implement full-range, preferably full-range, angular measurements of coatings. In the context of this document, the term "full range" generally refers to a range of 180°, or ±90°, relative to the normal to the coated plate being tested. The full range may be other than ±90° for specific implementations. In contrast, conventional measurement techniques typically measure discrete angular ranges only in air. For example, a standard single-beam or double-beam spectrophotometer with optional special modules adds 70° transmission in air and 45° reflection in air. For measurements on glass, conventional methods assemble the coating into a prism assembly and measure performance over a range of up to ±5°. The measurement angle is limited to the angle of the prism in the assembly (±5°).

[0027] Snell's law limits the angle of incidence of a plate that can be measured, with respect to total internal reflection (TIR) ​​and the dependence of the path of light through a material. For example, consider an exemplary ray of light traveling from glass to air. The critical angle θ ct is the value of the angle of incidence θ1 in the glass using Snell's law for light traversing from one optical medium to another 、 The exit angle θ2 in air is equal to 90°, i.e., the refractive indexes n1 and n2 of the exemplary glass and air are approximately 1.52 and 1, respectively, giving a value of approximately 41°. Therefore, measurements in air cannot reproduce measurements of angles greater than approximately 41° in glass.

[0028] For simplicity, the term "coated plate" may be referred to as either a "plate" or a "coating," as the context dictates. Current typical plate sizes are 70 x 70 mm (millimeters) and 60 x 30 mm. In the context of this document, the term "coated plate" generally refers to a plate with an optical coating on its surface. The coating is typically a multilayer thin film. Coated glass plates are generally used in this description, but are not limited thereto; other samples of other materials and shapes may be used. In general, the plate can be any non-air-shaped material that allows a free, unscattered light path between the light source and the photodetector. The test device can measure any sample of optical material (sample, optical element), such as thin film, glass, or plastic polarizers, wave plates, beam splitters, dichroic reflectors, light guide optical elements (LOEs), and structured optical elements such as gratings or wire grids. Optical filters (coatings) are used to manipulate incident light (incident on the coated plate) to specified reflectance, transmittance, absorption, polarization, etc. Optical measurements are used to test (probe and measure) the coating and / or to compare the actual performance of the coating with the specified required performance of the coating.

[0029] Similarly, for simplicity of this description, the term "glass cylinder" is used, but is not limited to it. For example, the material of the cylinder (cylinder, cylinder ring, sphere, bulk, half bulk, etc.) may be a polymer (one non-limiting example is an optically non-birefringent polymer).

[0030] The described apparatus and method embodiments can be used for characterization, measurement, and testing. The apparatus can be implemented for a variety of functions, including acceptance measurement of coating equipment and processes (coating materials on glass plates, etc.). For simplicity of this document, the term "testing" is used but should not be considered limiting.

[0031] Referring now to the drawings, FIG. 1A is a sketch of an apparatus for characterizing (testing) a full range of optical samples, and FIG. 1B is a sketch of a cross-section of the apparatus. Test apparatus 400 is generally referred to as a "jig" in the context of this document. Test apparatus 400 holds the plate under test, a support structure, guides the elements, and provides repeatability, precision, and interchangeability of the test. Test apparatus 400 includes a base 402 to which various other elements are mounted. An exemplary optical material to be tested is a coated plate 102 seated within a receptacle 110 of a rotatable assembly. The rotatable assembly includes a cylinder 100 and a turntable. Cylinder 100 includes a hollow 111. The turntable may be implemented by a bottom portion 406 having a motor mounting area 408B to which a motor 408A is connected. Receptacle 110 is filled with fluid 112, which in some implementations is an index-matching fluid. Positioning pins 410 can be used to clamp the cylinder 100 between the top portion 404 and the bottom portion 406. Exemplary side containment of the fluid 112 is shown as ribs 100S. The input test light source 4 provides an optical input signal to the collimating optics 6 via an optional input cable 6F. The collimating optics 6 prepares the input signal for input to the rotatable cylinder 100. The prepared light beam provides collimated illumination for testing. The output optics 106 feeds an optional output cable 104F to the output light collector (photodetector) 104.

[0032] For ease of reference, the rotatable cylinder 100 will be referred to as the cylinder 100 in the context of this document. The rotatable cylinder 100 is typically a solid material, an optical material, that is transparent to optical light beams. The interior of the rotatable cylinder 100 is substantially filled with a solid material, with at least a majority of the interior being filled with a solid material other than the fluid 112. The shape of the cylinder 100 can generally be what is known by some authors in the field of mathematics as a "general cylinder." A general cylinder is defined as a category of solids that includes prisms as a form of cylinder. Because the receptacle 110 can be formed in both cylinders and prisms, the term "general cylinder" is used to include embodiments that use either a cylinder or a prism. Thus, the rotatable cylinder 100 can have the shape of a cylinder or a polygonal prism. For example, the rounded surface of the cylinder allows for any rotation angle to be used on the cylinder (and therefore for measuring the coated plate 102) while maintaining the optical input and output substantially perpendicular to the surface of the cylinder 100. For example, if only 5 or 10 discrete measurements are required, a 10- or 20-sided polygonal circumference can be used, and the motor is limited to 18- or 9-degree steps. More generally, the shape of cylinder 100 can be any non-air shape that allows a free, unscattered light path from optical source 4 to optical detector 104. Based on this description, one skilled in the art will be able to design other devices and system components accordingly.

[0033] The cylinder 100 can be stationary, rotate on a single axis, or rotate on one or more axes to move the plate 102 for testing various angles of incidence and regions of the plate. The present description and illustrations only refer to the cylinder 100 rotating about a fixed axis (the height axis of the cylinder). Based on this description, one skilled in the art will be able to design and implement one or more movement directions and tests for the plate 102.

[0034] For ease of reference, the input signal is shown entering the cylinder 100 from the left side of the figure, with the corresponding labeled first side being the left side of the cylinder 100L. The labeled second side is the right side of the cylinder 100R adjacent the output optics 106, which feeds the optional output cable 104F to the output light collector 104. It will be apparent to those skilled in the art that the cylinder 100 is generally substantially symmetrical. The cylinder 100 can be rotated horizontally, and the left and right sides of the cylinder 100L and 100R can be interchanged. In a non-limiting example, the cylinder 100 can be implemented as a single (glass) piece with a central hollow 111 for the receptacle 110. In this case, the left side of the cylinder 100L and the right side of the cylinder 100R are opposite sides of the same piece. The hollow 111 can extend the full height of the cylinder (top to bottom) or can be partial, for example, forming a pocket within the cylinder. In another non-limiting example, cylinder 100 can be made from two pieces, the first piece being the first, left side of cylinder 100L and the second piece being the second, right side of cylinder 100R.

[0035] The collimating optics 6 and output optics 106 are preferably adjustable in at least two degrees of freedom to allow for alignment, initial and subsequent calibration of the light beam. For example, the collimating optics 6 and output optics 106 may be adjusted ±0.5 mm along the x and y axes of the light beam path.

[0036] In some implementations, the fluid 112 is an index-matching fluid. For ease of reference, the index-matching fluid 112 will be referred to as "fluid 112" in the context of this document. In some implementations, the fluid 112 has a refractive index that matches the refractive index (of the material / glass) of the cylinder 100. In some implementations, the fluid 112 has a refractive index that matches the refractive index of the plate 102. In some implementations, the cylinder 100 and the plate 102 are made of the same material (and therefore have matching refractive indices). Similarly, one or more of the refractive indices of the fluid 112, the plate 102, and the cylinder 100 can differ from one another. Those skilled in the art will recognize the tolerances regarding the particular index matching and the range of difference between the refractive indices of the elements.

[0037] The input cable 6F and the output cable 104F are typically optical fibers, but may be any suitable transmission medium depending on the particular implementation.

[0038] The testing apparatus 400 typically includes a top portion 404 and a bottom portion 406 for supporting and mounting various cylinders 100. Locating pins 410 can be used to attach the top portion 404 to the bottom portion 406, clamping the cylinder 100 between the top and bottom portions and facilitating the use of alternative cylinders 100, top portions 404, and bottom portions 406. For example, the top portion 404 can be modified with a second top portion including a different size and / or configuration of receptacles to test different plates. Or, for example, a cylinder made of a first material having a first refractive index for testing plates having a first refractive index can be replaced with a cylinder made of a second material having a second refractive index for testing plates having a second refractive index. In another example, the cylinder, top portion, and bottom portion are all replaced with alternative elements having (creating) wider / thicker receptacles for testing thicker plates or to create receptacles of different shapes, e.g., for testing round optical samples.

[0039] The cylinder 100 can be rotated by various means. In this figure, an exemplary motor mounting area 408B is provided at the bottom of the bottom portion 406 and is also shown with a motor 408A connected to it. In this case, the motor 408A, in typical combination with the bottom portion 406, functions as a general turntable for rotating the cylinder 100 about its height axis. The cylinder 100 and turntable form a rotatable assembly. Rotating the rotatable assembly rotates the cylinder 100, thereby rotating the receptacle 110 and the sample (coated plate 102). The controller 800 is operably connected to the motor 408A in this figure and is not shown in all figures for clarity. An encoder operably connected to the rotatable assembly is not shown. The encoder provides position information regarding at least the rotation angle of the rotatable assembly, so that the position of the coated plate 102 is known relative to the axis of the cylinder 100 and relative to the angle relative to the normal to the coated plate 102 (the optical sample being tested). As is known in the art, the position encoder may be part of the motor 408A or may be a separate component.

[0040] For reflectance measurements, output optics 106 is typically positioned at a different angle than shown in the drawing to collect the beam reflected from plate 102 under test.

[0041] The base 402 provides mounting arrangements for various jig components for receiving, adjusting, and aligning the optical arrangement (optical test light source 4, input cable 6F, collimating optics 6, output optics 106, output cable 104F, and output light collector 104) according to the particular test configuration, such as a motor 408A, a motor mounting area 408B, and a bottom portion 406.

[0042] Referring now to the drawings, FIG. 2 is a sketch of a top view of the cylinder 100. The optional input cable 6F and optional output cable 104F are not shown in this view. The test light source 4 provides an optical input signal to the collimating optics 6. Similarly, the output optics 106 feed the output light collector 104. Optionally, the optical input signal is input through a polarizer and a 90°±1° rotator, either before or after a fixed lens. The coated plate 102 is mounted in a receptacle 110 and surrounded by a fluid 112. Side containment of the fluid 112 is not shown in this top view. Based on this description, one skilled in the art will be able to design and implement appropriate containment for the fluid, for example, by using a top portion 404 extending around the cylinder 100. A controller 800 is typically operably connected to at least the test light source 4 and the output light collector 104.

[0043] Plate 102 has a first dimension horizontally (up and down on the page of the figure, along the axis of cylinder 100) designated as plate width 102W and a second dimension designated as plate thickness 102T (side to side on the page of the figure). Similarly, and correspondingly, receptacle 110 has a first dimension designated as receptacle width 110W (up and down on the page of the figure, along the axis of cylinder 100) and a second dimension designated as receptacle thickness 110T (side to side on the page of the figure). Receptacle width 110W may be slightly smaller than diameter 100W of cylinder 100, depending on the size of the implementation of side containment of fluid 112. As noted above, in this figure, side containment is not shown, and receptacle width 110W is shown as being the same size as diameter 100W of cylinder 100. Receptacle thickness 110T is the distance between the left side of cylinder 100L and the right side of cylinder 100R. Alternatively, receptacle width 110W may be a different size than cylinder diameter 100W, for example, receptacle width 110W is smaller than cylinder diameter 100W.

[0044] Typically, the plate 102 and receptacle 110 are substantially parallel, i.e., the width of the plate (plate width 100W) and the width of the receptacle (receptacle width 110W) are aligned. The sides of the receptacle 110 (the edges of the receptacle away from the area of ​​the receptacle 110 used to perform measurements on the plate 102) are typically parallel, but need not be. Depending on the specific measurement required, the distance between the sides of the receptacle at the edges of the receptacle can be closer, or preferably farther, than the distance between the sides of the receptacle in the core region 110C where the measurements are performed. The core region 110C is also known as the "critical region" and is where the coating is tested, i.e., where the light beam encounters the coated plate 102. Typically, the core region 110C is small, and the remaining area of ​​the receptacle 110 can be designed primarily to support the sample test plate 102. A typical core region 110C includes a minimum defined cylindrical measurement zone of ±10 mm.

[0045] A feature of this embodiment of test fixture 400 is that receptacle 110 is small compared to bath 5100 of bath jig 500. An alternative embodiment using a fluid bath is described below with reference to bath jig 500 of FIG. 5A. Bath 5100 typically holds between 300 cc (cubic centimeters) and 2000 cc of fluid. Conventional baths require at least 300 cc of fluid; otherwise, the fluid level is lower than the input and output of the light source and measurements are taken in air (not fluid). Typically, the volume of the bath is approximately 500-600 cc.

[0046] In contrast, the receptacle 110 typically holds 0.5 cc to 50 cc of fluid. The receptacle 110 may be adjustable in one or more dimensions to accommodate plates 102 of various sizes. Another feature of this embodiment of the testing apparatus 400 is that the cylinder 100 is rotated (as part of a rotatable assembly); therefore, the sample to be tested, the coated plate 102, is stationary relative to the fluid 112 and the receptacle 110. In contrast, in the bath jig 500, the sample (coated plate 102) is rotated within the fluid, i.e., within the bath 5100. Due to the high viscosity of the fluid 112, the rotation of the plate 102 within the fluid 112 within the bath jig 500 causes turbulence within the fluid 112, which in turn affects the measured spectrum. This problem is at least partially solved by the use of the cylinder 100.

[0047] Referring now to the drawings, FIG. 3 is a sketch of a cross-sectional side view of the cylinder 100 and bottom portion 406. The plate 102 has a third dimension shown vertically (up and down on the page of this figure, along the height axis of the cylinder 100) as the plate height 102H. Similarly, and correspondingly, the receptacle 110 has a third dimension shown as the receptacle height 110H. The receptacle height 110H may be the same size as the cylinder height 100H of the cylinder 100. Alternatively, the receptacle height 110H may be a different size than the cylinder height 100H. For example, the receptacle height 110H may be smaller than the cylinder height 100H to account for fluid containment implementation (sealing) within the hollow 111 at the bottom of the hollow 111, between the left and right sides 100L and 100R of the cylinder. Or, for example, the receptacle height 110H may be greater than the cylinder height 100H (as shown in this figure), and the bottom portion 406 may provide a seal at the hollow bottom (below) of the receptacle 110.

[0048] Referring now to the drawings, Figure 4 is a sketch of a top view of the cylinder 100 around which the coated plate 102 is rotated during testing. In this non-limiting example, the coated plate 102 is rotated approximately 90° clockwise from the starting position shown in the figure above.

[0049] As can be seen in this figure, a light beam 420, in this case optical light (as a test signal), is provided 420A by a test light source 4 (optional input cable 6F is not shown). The provided light beam 420A is prepared and collimated by collimating optics 6 and then input 420B perpendicular to the surface area of ​​the rotatable cylinder 100. The accuracy of the shape of the cylinder 100 can be determined by the required accuracy of the measurement of the coating on the plate 102. The light beam travels 420C through the left side of the cylinder 100L until it reaches the receptacle 110. The light beam traverses 420D-420E from the left side of the cylinder 100L into the fluid 112 in the receptacle 110, through the coated glass plate 102 (note that the coating on the glass plate is not shown), through the fluid 112 on the opposite side of the plate 102, and to the right side of the cylinder 100R.

[0050] The signal then traverses 420F to the right side of cylinder 100R and exits 420G perpendicular to the surface of rotatable cylinder 100. Output optics 106 pass the output light beam as output signal 420H to output light collector 104 (optional output cable 104F is not shown in this view).

[0051] Because the cylinder has only one circumferential surface, references to the input and output optical light beams are to different areas or regions of the surface. Correspondingly, the first and second sides of the cylinder are directional references, as shown on the page and as can be seen in the drawings.

[0052] Detailed Description - Alternative Device - Figures 5A-5B. Referring now to FIG. 5A, FIG. 5A is a sketch of a bath jig apparatus for testing the transmittance of optical samples, and FIG. 5B is a sketch of a cross-section of the bath jig apparatus. The testing bath jig apparatus 500 is generally referred to in the context of this document as a "bath jig" 500. The bath jig 500, like the test fixture (jig) 400, holds the plate, support structure, and guides the elements to be tested. The bath jig 500 includes a base 5402 to which various other elements are mounted. The coated plate 102 to be tested is seated within a plate mounting portion 5110 within a bath 5100. The bath 5100 is an area of ​​the bath jig 500 constructed to contain a fluid. The bath 5100 is a hollow space inside the bath jig 500 designed as a fluid containment area. The bath 5100 is filled with a fluid 112 (not shown in this figure). Test light source 4 provides an optical input signal via optional input cable 6F (not shown) to collimating optics 5006. Collimating optics 5006 (preparing and focusing) collimates the input signal onto bus 5100.

[0053] The plate mount 5110 can be rotated by a variety of means. In this figure, an exemplary motor mounting area 5408B is provided on the top of the bass jig 500 and is also shown with a motor 5408A connected to it.

[0054] As can be seen in FIG. 5B , a light beam 5420, in this case optical light, is provided 5420A by test light source 4. The provided 5420A light beam is prepared and expanded by collimating optics 5006 and traverses into fluid 112 in bath 5100. The light beam then travels 5420C through fluid 112 in bath 5100, through coated glass plate 102 (note that the coating on the glass plate is not shown), and through fluid 112 on the opposite side (of plate 102) 5420F. When bath 5100 is filled with fluid 112, this traversal of the light beam through bath jig 500 is substantially refraction-free. A signal is then output 5420E from fluid 112 to output optics 5106 5420H, which provides an output signal to output light collector 104.

[0055] The bath jig 500 is shown with optional front and back windows 5130F and 5130B that allow viewing of the internal bath 5100, plate mount 5110, coated plate 102, and other components.

[0056] Both the test fixture (jig) 400 and the bath jig 500 can include optional, additional, and alternative configurations. In one alternative, the jig can be adapted to include a vacuum, such as a vacuum bell, to extract dissolved air from the fluid 112. As another alternative, mechanical and / or other reinforcement can be used to handle and prevent rocking within the jig. Rigid fixation (rigid routing) can be used for the optical fiber. The receptacle 110 and plate mounting portion 5110 can be adjustable to accommodate plates 102 of varying sizes. As described above with respect to the location pin 410, the jig, top portion 404, and bottom portion 406 can be removable (removably attached) to facilitate replacement with cylinders of different refractive index and ease of operation (e.g., sample placement and cleanup).

[0057] Additional alternative examples of the jig can include a dark (light opaque) box that covers the entire jig, a dynamic receptacle for the test plate to prevent scratching the plate 102, a rotation stage including an engine and driver, an internal clean option, bubble extraction (stagnation area), and a sample plate squeezer.

[0058] Detailed Description - Method - Figures 6A to 7B Referring now to FIG. 6A, a flowchart of a method for characterizing an optical sample is shown. This method can be used with test fixture (jig) 400 and bath jig 500, as well as the MPL test fixture 1450 described below, as described in the test sequence below. A test method 610 for characterizing an optical sample begins in step 600, in which a light beam 420 is provided perpendicular to the cylinder 100. The light beam is typically an optical light beam, referred to as "input light" or simply "light," as will become apparent to those skilled in the art from the context of this description. Providing the light at a constant normal to the cylinder 100 facilitates the majority of the light coupling into the cylinder 100, ensuring that no, or minimal, light is lost upon entering the cylinder. Exemplary coatings include filters that transmit one portion of the visible spectrum and reflect another, polarizing filters that transmit one polarization state and reflect another, or absorbing coatings that absorb a portion of the visible light.

[0059] In step 601, an optional configuration is used, as described below.

[0060] In step 602, the output light is collected after traversing the cylinder 100, the receptacle 110, and the plate 102, as described above. The output light may be collected, for example, with a spectrometer.

[0061] In step 604, the plate 102 is rotated. The amount by which the plate is rotated depends on the specific requirements of the test being performed and the desired measurements. Exemplary rotations include 0.5° and 1° steps. After rotating the plate, the output light may be collected again at a new, known angle (step 602). This cycle of rotation and collection may be repeated as necessary to gather data for the desired range of angles to be tested (step 604 returns to step 602).

[0062] Note that a feature of this embodiment is that plate 102 is rotated by rotating the entire cylinder 100, as opposed to conventional implementations in which the test sample is rotated inside the test apparatus, e.g., in a bath of fluid in a test chamber. In step 606, optional calculations (processing, signal processing) are performed on the collected signals to determine figures of merit for the transmittance and / or reflectance of the coating and / or plate 102. Data from the collected output light 602 is processed to calculate the results of the optical test.

[0063] In step 608, the results of the collection and processing may optionally be displayed (output, transferred, stored, etc.).

[0064] Referring now to Figure 7A, a plot of transmittance (y-axis) versus angle (x-axis) is shown, and Figure 7B shows a close-up (zoom-in) of the transmittance plot of Figure 7A. Generally, a successful coating is indicated by a horizontal orientation of the plot, indicating that the coating had consistent transmittance over a range of angles. Transmittance (the amount of light provided minus the amount of light collected) may be s- or p-polarized.

[0065] Detailed Description - Controller - Figure 8 8 is a high-level partial block diagram of an exemplary controller 800 configured to implement the method for optical sample characterization 610 of the present invention. The controller (processing system) 800 includes a processor(s) 802 and four exemplary memory devices: random access memory (RAM) 804, boot read-only memory (ROM) 806, mass storage (hard disk) 808, and flash memory 810, all of which communicate via a common bus 812. As known in the art, processing and memory may include any computer-readable medium storing software and / or firmware and / or any hardware elements, including, but not limited to, field programmable logic array (FPLA) elements, hardwired logic elements, field programmable gate array (FPGA) elements, and application-specific integrated circuit (ASIC) elements. Any instruction set architecture may be used in the processor 802, including, but not limited to, reduced instruction set computer (RISC) architecture and / or complex instruction set computer (CISC) architecture. The processing module 814 is shown on the mass storage device 808, but can be located on any memory device as will be apparent to those skilled in the art.

[0066] Mass storage device 808 is a non-limiting example of a non-transitory computer-readable storage medium having computer-readable code for implementing the testing methodology described herein. Other examples of such computer-readable storage media include read-only memory, such as a CD, having such code.

[0067] The controller 800 may have an operating system stored on a memory device, the ROM may include boot code for the system, and the processor may be configured to execute the boot code to load the operating system into RAM 804, copy computer-readable code to RAM 804, and execute the operating system to execute the code.

[0068] Network connection 820 provides communication to and from controller 800. Typically, a single network connection provides one or more links, including virtual connections, to other devices on local and / or remote networks. Alternatively, controller 800 may include two or more network connections (not shown), each providing one or more links to other devices and / or networks.

[0069] The controller 800 may be implemented as a server or a client connected to a client or server, respectively, via a network.

[0070] DETAILED DESCRIPTION - ALTERNATIVE DEVICES - FIG. 9-FIG. 15 Referring now to FIG. 9, which is a sketch of an apparatus for full-range optical sample characterization (testing), and FIG. 10 is a sketch of an exploded view of the apparatus. The variable position test fixture 1450 will also be referred to in the context of this document as the "MPL apparatus" or "MPL." The term "MPL" refers to the typical, non-limiting use of the test fixture 1450: "plate mounted in liquid." The core MPL apparatus can be configured similarly to the test fixture 400 described above, with support structures, bases, and associated elements not shown in this figure but apparent to those skilled in the art.

[0071] The MPL device 1450 can be configured within a spectrophotometer measurement setup (tool) to create a more complete MPL test system, which provides apparatus and methods for testing and measuring, including but not limited to, reflectance, transmittance, and chromaticity of a coating between a base plate material and an incident material for different angles relative to the coating on the plate.

[0072] The cover 1403 is attached to the top portion 1404 of the MPL cylinder. The test MPL cylinder 1100 is between the top (top portion) 1404 of the MPL cylinder and the bottom (bottom portion) 1406 of the MPL cylinder. The gasket 1405 is a non-limiting example of a part used to help operatively configure the MPL test fixture 1450, in this case designed to seat in a groove and compress during assembly between two or more parts to create a seal at the interface between elements of the fixture.

[0073] Similarly to and corresponding to the test fixture 400 described above, an exemplary optical material to be tested (a sample of optical material) is a coated plate 102 seated in the MPL test fixture 1450. The MPL cylinder 1100 includes an MPL hollow 1111 in at least a portion of the interior of the MPL cylinder 1100. Typically, the MPL hollow 1111 is a central hollow on the axis of the MPL cylinder 1100. The MPL hollow 1111 is sized to receive at least a core region of the sample of optical material (coated plate 102). The MPL hollow 1111 is an interior portion of an MPL receptacle 1110. The MPL receptacle 1110 is sealed to receive a volume of fluid 112 such that the fluid 112 surrounds and contacts at least the core region of the coated plate 102, and the fluid 112 contacts the MPL cylinder 1100. As will be apparent to one skilled in the art, in this description, references to the fluid 112 in the MPL hollow 1111 can also be references to the fluid 112 in the MPL receptacle 1110. In some implementations, the refractive index of the glass of the MPL cylinder 1100 matches the refractive index of the fluid 112. In some implementations, the MPL cylinder 1100 and the plate 102 are made of the same material (and therefore have matching refractive indices). One skilled in the art will recognize the tolerances regarding the specific index matches and ranges of difference between the refractive indices of the elements.

[0074] A feature of this embodiment is that the coated plate 102 is mounted on a cylinder with circular symmetry, the MPL cylinder 1100. This allows for the measurement of light reflected by the plate 102 at different angles, especially large angles relative to the normal to the surface of the plate 102.

[0075] Referring now to the drawings, Figure 11A is a cross-sectional view of the MPL test fixture, and Figure 11B is a rotated cross-sectional view. As can be seen in this figure, plate 102 is preferably positioned (mounted) with its diagonal on the equator (see Figure 14A, equator 1100E) to increase the inspection area (core area) and allow for a larger angle of inspection (AOI) without vignetting.

[0076] Referring now to FIG. 12, a sketch of an MPL test fixture including a variable positioning mechanism is shown. The MPL test fixture 1450 can change position, particularly optionally and preferably all 6 degrees of mechanical positioning. Positioning includes remaining stationary, rotating in a single axis, rotating in one or more axes, raising, and lowering to move the plate 102 for testing various angles of incidence and regions of the plate. A non-limiting exemplary implementation for changing the position of the fixture is to use a variable positioning mechanism 1408A, e.g., a mechanical actuator for precise positioning. The variable positioning mechanism 1408A is suitably operably mounted to the MPL cylinder bottom portion 1406 and typically to a base (not shown, as is the test fixture 400 base 402). An exemplary implementation is the variable positioning mechanism 1408A being a turntable, mounted by the MPL cylinder bottom portion 1406 having a motor mounting area to which a motor is connected. The variable positioning mechanism 1408A changes the position of the MPL test fixture 1450, thereby changing the position of the plate 102.

[0077] Preferably, the MPL cylinder 1100 should be mounted (configured) to minimize obstructions surrounding the MPL cylinder 1100. This allows measurements at the largest range of angles around the MPL cylinder 1100 (substantially 360°) and therefore direct visibility of the plate 102 within the MPL cylinder 1100. Locating pins 410 can be used to clamp the MPL cylinder 1100 between the MPL cylinder top portion 1404 and the MPL cylinder bottom portion 1406. Two exemplary locating pins 410 are shown in this figure. When used, these locating pins 410 are positioned with the desired measurement angle in mind, minimizing obstructions with the pins within the desired range of test angles.

[0078] The MPL cylinder top portion 1404 and the MPL cylinder bottom portion 1406 can be used to support and mount various implementations of the MPL cylinder 1100. For example, the MPL cylinder 1100 can be clamped between the top and bottom portions, facilitating the use of alternative MPL cylinders 1100, top portions 1404, and bottom portions 1406. For example, the top portion 1404 can be modified with a second top portion including receptacles of a different size and / or configuration to test different plates. Or, for example, a cylinder constructed of a first material having a first refractive index for testing plates having a first refractive index can be replaced with a cylinder constructed of a second material having a second refractive index for testing plates having a second refractive index. In another example, the cylinder, top portion, and bottom portion are all replaced with alternative elements having (creating) wider / thicker receptacles for testing thicker plates or for creating receptacles of different shapes, e.g., for testing round optical samples.

[0079] The controller 800 is connected to the variable positioning mechanism 1408A and functions with the test fixture 400 and motor 408A, as well as the operation of the controller 800. For clarity, the controller 800 is not shown in all figures. Optionally, the positioning items 1107 (e.g., pins) can provide dynamic freedom for interchangeably removing the MPL test fixture 1450 and returning it precisely to a given position.

[0080] Referring now to FIG. 13, a cross-section of an MPL cylinder for plate testing is shown. The plate 102 is mounted inside the MPL cylinder 1100. The plate 102 has a first surface, referred to herein as the "target reflective surface" 102L, "target surface," "coated surface," or "front surface." The target surface 102L is typically the surface of interest to be tested and may be coated with one or more coatings. Alternatively, the target surface 102L may be uncoated. The plate 102 has a second side opposite the first side, referred to herein as the "rear surface" 102R. The rear surface 102R is typically uncoated but may be coated with one or more coatings. For simplicity, the coatings are not shown. For ease of reference in the figures, the target surface 102L is typically the "left side" of the first surface, the MPL cylinder 1100, and the plate 102, depicted facing left on the page. Correspondingly, the back surface 102R is the second surface, depicted facing right on the page, and is the "right side" of the MPL cylinder 1100 and plate 102. As explained above (see Figures 11A and 11B), the plate 102 may be mounted so that the target reflective surface 102L is at the center of the diameter of the MPL cylinder 1100. The MPL cylinder 1100 has an MPL cylinder diameter 1100D from the outer outer surface 1100U to the opposite outer surface, and an MPL cylinder thickness 1100T from the outer surface 1100U to the circumferential ring inner surface 1100N.

[0081] Similar to the optical arrangement used to test the test apparatus 400 described above, a light beam 420 is provided 420A as an optical input signal from an input test light source 4. The provided 420A light beam is optionally prepared and collimated by collimating optics 6 and then input 420B perpendicularly to the surface area of ​​the MPL cylinder 1100. The light beam travels 1420C (via the "left side") toward the target surface 102L of the plate 102, where it impinges on the (coated) target surface 102L. In this illustration, the hollow 1111 is the entire interior portion of the MPL cylinder 1100, and the fluid 112 fills the hollow 1111 and surrounds the plate 102, in contact with both the target surface 102L and the back surface 102R. In this case, the light beam travels 1420C through the fluid 112 toward the target surface 102L of the plate 102 via the left side.

[0082] A normal 1115N is defined perpendicular to the surface of plate 102 at the core region where light beam 1420C impinges on target surface 102L of plate 102. A test angle θ (theta, 1115) is defined between the line of light beam 1420C and normal 1115N. Target surface 102L of plate 102 is closer on the side facing test light source 4 compared to rear surface 102R of plate 102, which is further away on the side of plate 102 opposite test light source 4.

[0083] After light beam 420 impinges on target surface 102L, a portion of the beam may be reflected from the surface of plate 102, as shown as reflected output beam 1420F. A portion of the beam may enter and traverse plate 102 (not shown in this figure, e.g., similar to the above description of test apparatus 400 and FIG. 4). The portion of the beam that reflects from and enters plate 102 is determined by the specific characteristics of the implementation, such as the refractive index of fluid 112 in hollow 1111 and receptacle 1110, the angle of incidence (test angle θ 1115) between the input signal (light beam 1420C) and plate 102, the refractive index and properties of any coatings, and the refractive index of plate 102.

[0084] In this reflectivity test, the output beam 1420F travels away from the target surface 102L of the plate 102 via the "left side." The output beam 1420F leaves the plate 102 via the same side of the plate 102 as the incident light beam 1420C traveling towards the plate 102. In the present case of a fluid 112 filling the hollow 1111 and surrounding the plate 102, the output beam 1420F travels from the target surface 102L, through the fluid 112, towards the inner surface of the MPL cylinder 1100. The output beam 1420F is emitted 420G normal to both the inner surface area (inner curved surface) and the outer curved surface of the MPL cylinder 1100. The output beam 1420F is optionally prepared by output optics 106 and sent to the output light collector 104 as output signal 420H. The optional input cable 6F, output cable 104F, and other supporting elements are not shown in this figure. As explained above, the collimating optics 6 and output optics 106 are preferably adjustable in at least two degrees of freedom to allow for adjustment, initial and subsequent calibration of the light beam.

[0085] A feature of this embodiment is that the location of the output light collector 104 is adjustable, particularly rotatably adjustable, relative to the location of the test light source 4 configured to receive a reflected signal from the plate 102 under test. The location of the output light collector 104 can be calculated based on implementation details (such as the location of the test light source 4, the refractive index, etc., as described above) or can be determined otherwise (e.g., experimentally). In one implementation, during rotation of the plate 102, the output light collector 104 is synchronized and rotated by twice the angle of rotation of the plate 102 about the same axis. For example, if the plate 102 is rotated two (2) degrees on the vertical axis of the MPL cylinder 1100, the output light collector 104 is rotated four (4) degrees around the outside of the MPL cylinder 1100. In alternative implementations, the output light collector 104 may be positioned by manually inspecting the location of the output light beam 420H or by measuring the intensity of the output signal 420H at the output light collector 104 and positioning the output light collector 104 to maximize the intensity of the received output signal 420H. Typically, the plate 102 is vertical and aligned parallel to the height axis of the MPL test fixture 1450. The light source 4 and light collector 104 are correspondingly in a horizontal plane, aligned with the diameter of the MPL cylinder 1100 and aligned with the normal 1115N to the surface of the plate 102. In other words, the output light collector 104 may be configured in a plane defined by the light source 4 and the normal 1115N.

[0086] The measurement of the transmission of the light beam 420 through the plate 102 is described above with respect to the test fixture 400 and the cylinder 100. Those skilled in the art will be able to apply the above description to this embodiment of the MPL test fixture 1450 with the MPL cylinder 1100, which will not be described in detail here.

[0087] Referring now to the drawings, FIG. 14A is a cross-sectional sketch and FIG. 14B is a cross-sectional sketch of an alternative implementation of an MPL cylinder. In FIG. 14A, the MPL cylinder 1100, and corresponding plate 102, are oriented and the light collector 104 is positioned for transmittance testing. In FIG. 14B, the MPL cylinder 1100, and corresponding plate 102, are oriented and the light collector 104 is positioned for reflectance testing. The target reflective surfaces 102L are parallel and aligned with the equator 1100E of the MPL cylinder 1100. The equator 1100E is the diameter of the cylinder. This figure also shows the MPL cylinder height 1100H, from the top side of the MPL cylinder 1100 for contacting the top portion 1404 of the MPL cylinder to the bottom side of the MPL cylinder 1100 for contacting the bottom portion 1406 of the MPL cylinder.

[0088] In the exemplary transmittance test implementation of Figure 14A, the plate 102 is perpendicular to the input test light beam 420, the test angle θ (1115) is 0° (zero degrees, shown in the figure for reference), and the output light collector 104 is located on the second side ("right side") 102R of the MPL cylinder 1100. Note that the normal 1115N in this illustration is drawn slightly offset from the light beam 420 so that the normal 1115N is visible. Bulk material 1100B is shown. Bulk material 1100B will be referred to as "bulk" in the context of this document and will be described below.

[0089] Referring now to the drawings, Figure 14B is a sketch of the MPL cylinder of Figure 14A, viewed from above at an angle. For clarity, plate 102 is not shown in this figure. In this figure, unlike Figure 14A, test light source 4 and output light collector 104 are configured for reflectivity testing of plate 102. Input test light beam 420 and output signal 420H are at an oblique angle to target reflective surface 102L.

[0090]

[0063] Referring now to the drawings, Figure 14C is a sketch of a cross-section of an alternative implementation of an MPL cylinder. In Figure 14A described above, most of the path of the test light beam (light beam 420 and output signal 420H) passes through the MPL cylinder 1100 via the fluid 112. In this figure, most of the path of the test light beam (420, 420H) traverses the MPL cylinder 1100 via the bulk 1100B and then via a small amount of fluid 112 (small relative to the length of the light path through the bulk 110B, or the size of the fluid 112 within the hollow 1111 of the half-cylindrical MPL cylinder 1100). In this figure, the MPL cylinder 1100, and correspondingly the plate 102, are oriented for reflectance testing, as are the light source 4 and light collector 104 positioned for reflectance testing. The target reflective surface 102L is parallel to and aligned with the equator 1100E of the MPL cylinder 1100. For reflectance testing, the light beam 420 is at a test angle θ(1115) relative to the normal 1115N to the plate 102 (or equivalently, perpendicular to the equator 1100E), and the output light collector 104 is located on the same side (the "left side", target reflective surface side) 102L of the MPL cylinder 1100 as the light source 4A bulk material 1100B.

[0091] When performing reflectance testing, it is desirable to reduce or eliminate reflections from surfaces other than the surface under test. For example, when testing the front target reflective surface 102L and / or a coating on the front surface 102L, a portion of the input light beam 420 may refract through the front surface 102L into the plate 102, then reflect off the back surface 102R and refract from the front surface 102L. As a result, a portion of the unwanted light may impinge on the output light collector 104 and interfere with the test. Unwanted reflections may also be generated, for example, from the fluid 112 within the hollow 1111 and the bulk 1100B on the right / back side of the MPL test cylinder 1100. Methods for reducing or eliminating reflections from the back surface 102R include constructing a non-reflective material within the hollow 1111. Alternatively or additionally, the back surface 102R can be roughened. Alternatively or additionally, the back surface 102R can be tilted so that it is not parallel to the front surface 102L.

[0092] A feature of this embodiment is that the circular MPL cylinder 1100 can be at least partially filled with bulk material 1100B. Correspondingly, a portion of the interior of the MPL cylinder 1100 forms the MPL receptacle 1110 (including the MPL hollow 1111), where this portion (the MPL hollow 1111) is smaller than the entire interior of the MPL cylinder 1100. In an exemplary implementation, the bulk 1100B is typically the same solid material as the MPL cylinder 1100 that is optically transparent to the light beam 420. The MPL cylinder can be constructed as a single piece of the same material as the bulk, thereby simplifying construction compared to other implementations. The use of bulk 1100B material in the interior of the cylinder reduces the amount of fluid 112 required to fill the receptacle 1110, thus alleviating the problem of relatively large fluid volumes in conventional bath implementations.

[0093] In a basic MPL cylinder 1100 as shown in FIG. 13, the cylinder has circular symmetry, with material only around the circumference, creating a circular interior chamber that creates an MPL receptacle 1110 and an MPL hollow 1111 inside the MPL cylinder 1100. However, this configuration is not limiting. In this illustration, the material creating the circumference of the MPL cylinder 1100 also partially fills the right side, almost completely filling the right half of the circular interior, forming a bulk 1100B portion. The bulk 1100B typically fills substantially half of the interior of the MPL cylinder 1100 (receptacle 1110). The bulk is substantially semicircular, and the corresponding receptacle 1110 (hollow 1111) is substantially semicircular. In a typical transmittance test as shown in FIG. 14A, substantially half of the path of the light beam traverses the bulk material 1100B. In a typical reflectance test, such as that shown in FIG. 14B, the majority of the light beam's path passes through the fluid 112. In a typical reflectance test, such as that shown in FIG. 14C, the majority of the light beam's path passes through the bulk 1100B, thereby avoiding known problems with test light propagating through a fluid, as the majority of the path passes through a solid material. As is known in the art, the fluid 112 (plate 102) surrounding the optical element to be tested can affect measurement accuracy due to fluid dynamics. In particular, the larger the volume of fluid, the greater the challenge of measurement accuracy. Therefore, it is desirable to reduce the amount of fluid 112 used in the device. Including the bulk 1100B portion in the MPL cylinder 1100 reduces the amount of fluid 112 required to fill the MPL receptacle 1110, and therefore the amount of fluid 112 required to fill the MPL hollow 1111. Using a similar concept of filling the area inside the MPL test fixture 1450 to minimize the amount of fluid 112 within the MPL cylinder 1100, the MPL cylinder top portion 1404 and the MPL cylinder bottom portion 1406 (not shown in this figure) may include solid portions at the bottom and top of each portion, respectively. Additionally, the height of the cylinder (MPL cylinder height 1100H of MPL cylinder 1100) may be optimized to reduce the height to the minimum height required for the desired measurement, thus reducing the size of the MPL receptacle 1110.The plate 102 can be placed in the smallest size receptacle on the top and bottom portions, thus minimizing the amount of fluid required.

[0094] As explained above, particularly with respect to the rotatable cylinder 100, the cylinder and bulk may be made of glass or another suitable material. Alternatively, the bulk may be filled with any solid object that does not have the reflection in the same direction as the coating, e.g., is opaque, highly diffuse, or polarizes in a different direction.

[0095] The MPL cylinder 1100 and the fluid 112 can have the same refractive index. Alternatively, the MPL cylinder 1100 and the fluid 112 can have different refractive indices. For example, the MPL cylinder 1100 can have a first refractive index, and the fluid 112 and the plate can have the same second refractive index. Thus, a single device can operate with a variety of plates 102.

[0096] Typically, the outer surface 1100U of the MPL cylinder 1100 is polished to facilitate normal input 420B of the input test light beam 420A into the cylinder. The inner surface 1100N of the MPL cylinder 1100 can be polished or unpolished. The precision (e.g., smoothness of the outer surface 1100U), size, and shape of the MPL cylinder 1100 can be determined by measuring the required precision of the coating on the plate 102.

[0097] Referring now to Figure 15, is a sketch of an alternative embodiment of an MPL cylinder. The vertical cross section of the MPL test fixture 1450 may be round, as shown in the previous figure (test MPL cylinder 1100), or may be an alternative shape, such as a complete or sliced ​​section of a hollow ball 1100X, as shown in this figure. Alternatively, it may be wedge-shaped, not shown.

[0098] Embodiments can include the above-described test fixture (jig) 400 and MPL test fixture 1450 mounted on a universal measurement accessory (UMA). In these cases, the UMA typically provides the input test light source 4. The UMA also provides a rotational mount that holds the fixture and rotates the fixture, thereby rotating the optical sample. For example, a turntable mounted by a motor mounting area 408B on the bottom portion 406 or a motor 408A to which a positioning item 1107 is connected rotates the fixture (400, 1450). Typically, the rotation is about the center of the sample, specifically about the height axis of the fixture. The UMA also typically provides a detector, e.g., an output light collector 104. The detector may be mounted on a lever (arm) that rotates around the optical sample and has an axis of rotation substantially the same as the axis of rotation of the fixture.

[0099] With this UMA configuration, the reflected light (input test light) can be aimed (deflected) at the detector at a range of angles by varying the angular rotation of the device (400, 1450) and the detector. Generally, the test device (400, 1450) and the output light collector 104 are configured as two elements having a substantially common axis, each rotating about a common axis, the device configured about an axis, and the collector rotating about the device.

[0100] Referring again to FIG. 6A, the flowchart of the method for characterizing an optical sample described above with respect to test apparatus 400 can be applied to MPL test apparatus 1450.

[0101] The test method 610 begins at step 600 where a light beam 1420 is provided perpendicular to the MPL cylinder 1100 .

[0102] In step 601, an optional configuration is used, as described above.

[0103] In step 602, output light is collected after traversing the MPL cylinder 1100, the receptacle 1110 and reflecting off the plate 102, as described above.

[0104] In step 604, plate 102 is rotated as described above. After rotating the plate, the output light may be collected again at a new, known angle (step 602). This cycle of rotation and collection may be repeated as necessary to collect data for the desired range of angles to be tested (step 604 returns to step 602).

[0105] In step 606, optional calculations (processing, signal processing) may be performed on the collected signals, and the data from the collected output light 602 may be processed to calculate the results of the optical test and determine figures of merit for the transmittance and / or reflectance of the coating and / or plate 102 of the optical sample under test.

[0106] In step 608, the results of the collection and processing may optionally be output, displayed, stored, and / or transmitted.

[0107] It should be noted that the examples, numerical values ​​used, and exemplary calculations described above are intended to assist in explaining the present embodiment, and any inadvertent typographical errors, mathematical errors, and / or the use of simplified calculations do not impair the usefulness and fundamental advantages of the present invention.

[0108] To the extent that the appended claims have been drafted without multiple dependencies, this has been done solely to accommodate formal requirements in jurisdictions that do not permit such multiple dependencies. Note that all possible combinations of features implied by multiple dependency claims are expressly contemplated and should be considered part of the present invention.

[0109] It will be understood that the above description is intended to serve as an example only, and that many other embodiments are possible within the scope of the invention as defined in the appended claims.

Claims

1. 1. An apparatus for optical testing of a sample of optical material, comprising: (a) a rotatable assembly, (i) an optically transparent general cylinder having a central hollow on an axis of the general cylinder, the hollow being sized to receive at least a core region of the sample of the optical material; (ii) a rotatable assembly comprising: a receptacle containing the hollow, the receptacle sized to receive at least a portion of the sample of optical material, the receptacle sealed to receive a volume of the fluid such that the fluid surrounds and contacts at least the core region and contacts the general cylinder; (b) a turntable aligned with said axis and operable to rotate said rotatable assembly about said general cylinder height axis; (c) an optical arrangement comprising: (i) aligned with said axis; (ii) a light source providing an optical light beam normal to a surface area on a first side of the generally cylinder; (iii) an optical detector that receives an output signal, the output signal comprising a reflection of the optical light beam from the surface area, the optical detector being perpendicular to the surface area of ​​the first side of the general cylinder.

2. 1. An apparatus for optical testing of a sample of optical material, comprising: (a) an assembly comprising: (i) an optically transparent general cylinder, the interior of which is partially filled with a bulk material portion from an inner surface of the general cylinder toward a central axis of the general cylinder, the interior having a hollow portion extending from an opposing inner surface of the general cylinder and including the axis, the hollow portion being sized to receive at least a core region of a sample of the optical material; (ii) an assembly comprising: a receptacle containing the hollow, the receptacle sized to receive at least a portion of the sample of optical material, and sealed to receive a quantity of the fluid such that the fluid surrounds and contacts at least the core region and contacts at least a portion of the general cylinder and the bulk; (b) an optical arrangement comprising: (i) aligned with said axis; (ii) a light source that provides an optical light beam normal to a surface area of ​​the first side of the general cylinder; (iii) an optical detector for receiving an output signal, wherein the output signal from the optical light beam impinges on the core region and the optical detector is perpendicular to a surface region of the generally cylinder.

3. the assembly is a rotatable assembly; 3. The apparatus of claim 2, further comprising: (c) a turntable aligned with said axis and operable to rotate said rotatable assembly about a height axis of said general cylinder.

4. The device of claim 2 , wherein the bulk fills substantially half of a semicircular shape of the receptacle.

5. 3. The apparatus of claim 2, wherein the bulk material is the same optically transparent material as the optically transparent material of the general cylinder.

6. 3. The apparatus of claim 1 or claim 2, further comprising a mounting arrangement that receives the optical arrangement and is adjustable to align the light source and the optical detector.

7. 3. The apparatus of claim 1 or claim 2, further comprising a clamping mechanism for fixing the location of the sample relative to the receptacle.

8. a motor operatively connected to the rotatable assembly and operable to rotate the rotatable assembly; The apparatus of claim 1 or claim 3, further comprising: an encoder operatively connected to the rotatable assembly and operable to provide position information related to at least an angle of rotation of the rotatable assembly.

9. 3. The apparatus of claim 1 or claim 2, wherein the general cylinder is selected from the group consisting of a cylinder and a prism.

10. 3. The apparatus of claim 1 or claim 2, wherein the refractive indices of the general cylinder, the sample, and the fluid are substantially equal.

11. 3. The apparatus of claim 1, wherein the fluid is an index-matching fluid, the refractive index of the sample and the fluid being substantially equal.

12. 3. The apparatus of claim 1 or claim 2, wherein the general cylinder and the sample of optical material are made of the same optically transparent solid material.

13. 4. The apparatus of claim 1 or claim 3, wherein the general cylinder is substantially symmetrical parallel to the height axis of the general cylinder.

14. The general cylinder is (a) stationary; (b) rotatable about a single axis; (c) rotatable about two or more axes; (d) rotatable through a predetermined range of angles; (e) being rotatable by ±90 degrees from normal to the sample.

15. 3. The apparatus of claim 1 or claim 2, wherein the core region of the sample is the location on the sample where a light beam encounters the sample and where testing of the sample is performed.

16. (a) the receptacle: (i) a receptacle width along a cylinder diameter of the general cylinder, the receptacle width being smaller than the cylinder diameter; and (ii) a receptacle thickness non-parallel to the receptacle width, the receptacle thickness being between a first side and a second side of the general cylinder; (b) the sample is (i) a plate width along the cylinder diameter, the receptacle width being greater than the plate width; and 3. The apparatus of claim 1 or claim 2, having (ii) a plate thickness that is not parallel to the plate width, the receptacle thickness being greater than the plate thickness.

17. The apparatus of claim 16 , wherein the receptacle width and the plate width are aligned substantially parallel.

18. 3. The device of claim 1 or claim 2, wherein the receptacle is configured to contain between 0.5 cubic centimeters (cc) and 50 cc of fluid.

19. The sample is (a) a glass plate; (b) a coated glass plate; (c) thin film polarizer, (d) glass polarizer; (e) a plastic polarizer; (f) beam splitter; (g) wave plate; (h) light guide optical element (LOE); (i) a structured optical element, (i) Regular lattice, (ii) holographic gratings; (iii) holographic volume gratings; (iv) a diffractive optical element; (v) Fresnel lenses; (vi) subwavelength photonic structures, and (vii) a wire grid.

20. 3. The apparatus of claim 1 or claim 2, wherein the optical element is coated with a coating, the coating being used to manipulate light incident on the sample.

21. The optical arrangement is 3. The apparatus of claim 1 or claim 2, comprising collimating optics for preparing the optical light beam and inputting the optical light beam into the general cylinder, the collimating optics being adjustable in at least two degrees of freedom.

22. 2. The apparatus of claim 1, wherein the optical path of the optical light beam passes through the general cylinder and the fluid, with a majority of the optical path passing through the general cylinder.

23. A controller operatively connected to the device of claim 1 or claim 3, comprising: (a) beginning to input an optical light beam perpendicular to a surface area of ​​a first side of the general cylinder; (b) positioning the general cylinder such that a light beam path traverses through a first side of the general cylinder until it reaches the hollow, then traverses from the first side into the fluid in the hollow on a first side of the sample, through the sample, through the fluid on the other side of the sample, into a second side of the general cylinder, traverses the second side, and exits perpendicular to a surface area of ​​the second side of the general cylinder as an output signal; (c) a controller configured to activate capture of the output signal by the optical detector.

24. The controller (a) positioning the general cylinder at a first angle of the sample relative to the light beam path; (b) rotating the general cylinder so that the sample is at a second angle relative to the light beam path; 24. The controller of claim 23, further configured: (c) repeating said capturing and said rotating.

25. 1. A method for optically testing a sample of optical material, comprising: (a) providing an apparatus according to claim 1 or claim 3; (b) inputting an optical light beam perpendicular to a surface area of ​​a first side of the generally cylinder; (c) positioning the general cylinder such that a light beam path traverses through a first side of the general cylinder until it reaches the hollow, then passes from the first side into the fluid in the hollow on a first side of the sample, through the sample, through the fluid on the other side of the sample, into a second side of the general cylinder, traverses the second side, and exits perpendicular to a surface area of ​​the second side of the general cylinder as an output signal; (d) capturing the output signal with the optical detector.

26. (a) after said positioning of the sample at a first angle relative to the light beam path; (b) rotating the general cylinder so that the sample is at a second angle with respect to the light beam path; 26. The method of claim 25, further comprising: (c) repeating said capturing and said rotating.

27. 27. The method of claim 26, further comprising the step of processing data collected by said capturing to calculate results of said optical testing.

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