Canyon Materials, Inc. - Calibration Plates














Calibration Plate HEBS5 (continued)


Part III:

The test pattern of Part III represents a wider range of tapered structures and is composed of a 9x9 array of via structures that are 800 microns in length, see Diagram 1. This test pattern has nine optical density ranges that are listed in Table I. There are 20 gray levels within each of the nine optical density ranges. Table II lists these 9 sets of 20 gray levels. The 20 OD values in each of the nine ranges vary in intervals of constant delta T. The OD range is consistent across a row, whereas the width and gap of the via structure is consistent down a column. Table III displays the dimensions of the via structures within each column. Diagram 2 defines the via gap and via width.

With this portion, together with Part II of the calibration plate, HEBS-glass users can determine the optical density (OD) range of a gray scale mask that is most appropriate for a particular device fabricated with existing in-house processes and equipment of photolithography and ion beam etching.

HEBS glass enables users to custom design prism gratings and v-groove spacers to achieve wavelength division multiplexing and for accurate alignment and positioning optical fibers.

Other tapered structures are used in applications such as read-write heads for magnetic disk drives.

 

Part IV:

Six test patterns numbered 1 through 6 for use to determine the optimum width of a graylevel or number of gray levels required. Each test pattern has 24 zones with 16 gray levels within each zone. The width of a gray level is one-sixteenth of the zone width. In test patterns 1, 2, and 3, the gray levels are defined by the transmittance values of the equation T = 0.748 - 0.04488i, where i = 0, 1, 2 . . . 15. In test patterns 4, 5, and 6, the gray levels are defined by the optical density values of the equation D = 0.126 + 0.06666i, where i = 0, 1, 2 . . . 15. The only difference among patterns 1, 2, and 3, and among patterns 4, 5, and 6 is the spacing between zones. The gray level width in each of the 24 zones is as follows:

The Width of one gray level

Zone 1: 6.0Ám

Zone 9 : 2.0Ám

Zone 17: 1.2Ám

Zone 2: 5.5Ám

Zone 10: 1.9Ám

Zone 18: 1.1Ám

Zone 3: 5.0Ám

Zone 11: 1.8Ám

Zone 19: 1.0Ám

Zone 4: 4.5Ám

Zone 12: 1.7Ám

Zone 20: 0.9Ám

Zone 5: 4.0Ám

Zone 13: 1.6Ám

Zone 21: 0.8Ám

Zone 6: 3.5Ám

Zone 14: 1.5Ám

Zone 22: 0.7Ám

Zone 7: 3.0Ám

Zone 15: 1.4Ám

Zone 23: 0.6Ám

Zone 8: 2.5Ám

Zone 16: 1.3Ám

Zone 24: 0.5Ám

 

Part V:

A 2mm x 2mm blazed grating having a 20 micron period is designed with two variable parameters in a 3 x 3 matrix depicted below. The first variable parameter is the optical density range. Three optical density ranges: 0.223 to 0.823, 0.223 to 1.023, and 0.223 to 1.223 are identified by labeling the values of maximum OD. The second variable parameter is proximity corrections aiming to minimize the width of backward slope or the rounding of the triangular cross-section within a blazed grating period. The grating has 20 gray levels within each period.

Part VI:

2 sinusoidal gratings, each of 1mm x 1mm in size. The first has a period of 10m m and the second has a period of 20m m. Each sinusoidal grating has 20 gray levels. The equation for the sinusoidal spatial modulation of the transmittance goes as T=(sinq +1)(D T)/2, where q =6.2832X/P, X = position of a gray level within a grating period. Period P is 10m m and 20m m for the first and the second grating respectively, and D T=Tmax-Tmin. The transmittance for both of the gratings varies from 59.8% to 2.5%. This range of transmission values corresponds to an OD range of 0.223 to 1.599.

The superior properties of sinusoidal test patterns and arrays of density wedges in HEBS glass encourages new as well as traditional applications such as: beam shaping filters, spatial filtering, waveguides, and MTF evaluation of materials, lenses, cameras, devices and electro-optical systems.

 

Part VII:

An array of refractive microlenses having a 100% fill factor. Each lenslet is 50m m x 50m m and is written with 32 gray levels. The OD range of the 32 gray levels is 0.129 to 1.017.

 

Part VIII:

Exemplary 4 x 5 subarrays selected from an array of microlenses having a variable lens parameter within the array. In this example, the lenslets within each subarray has a unique compound tilt. The facet centerline angle of each lenslet is the variable parameter and is a function of distance r from the optical center of the lens array. The range of facet centerline angles displayed is from 4.277 to 17.23 degrees. Each lenslet is 57m m x 57m m and is written with 20 gray levels. The lens sag and thus the OD range of the gray levels within a lenslet increase with an increasing facet centerline angle. HEBS-glass enables users to create new as well as traditional designs of microlens arrays.

 

Instructions for viewing mask patterns under an optical microscope: Please view mask patterns in the HEBS-glass under a microscope in a transmission mode (i.e. using the bottom light); the mask pattern has little or no contrast in a reflection mode (i.e. using the top light) because the reflectance of HEBS-glass is about 4% in both clear and e-beam darkened areas.

Instructions for handling and storage: Since the mask pattern is inside the glass, HEBS-glass masks can be washed like a quartz glass substrate, using any solvent or acid (except HF). Strong base solution may cause pits in the surface of HEBS-Glass or any silicate glass. HEBS-Glass masks should be kept at room temperature. Humidity levels from 0 to 100% do not affect HEBS-glass masks.

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