# US 5,706,080 A · Single test station that can test a flying height and electrical characteristics of a recording head > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,706,080 A - Document ID: US5706080A - Status: Granted - Kind: A - Application number: 08/762,136 - Filed: 1996-12-09 - Granted: 1998-01-06 - Earliest claimed: 1996-12-09 - Assignees: Phase Metrics - Inventors: David F. Pekin; Ashok Machcha - Web page: https://patentgrep.com/patent/US5706080A ## CPC - G11B 5/6005: {Specially adapted for spacing from a rotating disc using a fluid cushion} - G01B 11/14: for measuring distance or clearance between spaced objects or spaced apertures (G01B11/26 takes precedence; rangefinders G01C3/00) - G11B 5/455: Arrangements for functional testing of heads; Measuring arrangements for heads - G11B 33/10: Indicating arrangements; Warning arrangements {(G11B15/04, G11B19/04, G11B27/34, G11B27/36 take precedence)} - G11B 5/012: Recording on, or reproducing or erasing from, magnetic disks (G11B17/00, G11B19/00 take precedence) - G11B: INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER (recording measured values in a way that does not require playback through a transducer G01D9/00; recording or playback apparatus using mechanically marked tape, e.g. punched paper tape, or using unit records, e.g. punched or magnetically marked cards G06K; transferring data from one type of record carrier to another G06K1/18; circuits for coupling output of reproducer to radio receiver H04B1/20; gramophone pick-ups or like acoustic electromechanical transducers or circuits therefor H04R) - G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS ## Abstract A tester which can measure both the air bearing thickness and the dynamic electrical characteristics of a head gimbal assembly (HGA) of a hard disk drive. The tester has a disk that is rotated by a spindle motor. The disk has a transparent portion that is used to measure the air bearing thickness and a magnetic portion that used to measure the electrical characteristics. The HGA is moved adjacent to the transparent and magnetic portions by a loader mechanism. The HGA is separated from the rotating disk by an air bearing. The tester has an optical system which measures the thickness of the air bearing when the HGA is adjacent to the transparent portion of the disk. The tester also has an electrical tester which measures the electrical characteristics when the HGA is adjacent to the magnetic portion. The loader mechanism moves the HGA between the transparent and magnetic portions so that the air bearing thickness and the electrical characteristics of an HGA can be measured in the same tester. ## Claims ### Claim 1 A tester for testing a recording head which has an electrical characteristic, comprising: a disk which has an optically transparent portion and a magnetic portion; a spindle motor which rotates said disk; a loader mechanism which can move the recording head between said optically transparent portion and said magnetic portion, wherein the recording head is separated from said disk by an air gap; an optical system that measures the air gap when the recording head is adjacent to said optically transparent portion of said disk; and, an electrical tester which measures the electrical characteristic of the recording head when the recording head is adjacent to said magnetic portion of said disk. ### Claim 2 (depends on 1) The tester as recited in claim 1, wherein said optically transparent portion is at an outer diameter of said disk and said magnetic portion is at an inner diameter of said disk. ### Claim 3 A disk for a tester which optically measures an air gap between a recording head and a disk, and measures an electrical characteristic of the recording head, comprising: a disk which has an optically transparent portion and a magnetic portion. ### Claim 4 (depends on 3) The tester as recited in claim 3, wherein said optically transparent portion is at an outer diameter of said disk and said magnetic portion is at an inner diameter of said disk. ### Claim 5 A method for testing a recording head which has an electrical characteristic, comprising the steps of: a) moving the recording head adjacent to an optically transparent portion of a disk, wherein the recording head is separated from the disk by an air gap; b) measuring the air gap with an optical system which directs a light beam through the optically transparent portion of the disk; c) moving the recording head adjacent to a magnetic portion of the disk; and, d) measuring the electrical characteristic of the recording head. ### Claim 6 A method for constructing a disk for a tester which optically measures an air gap between a recording head and a disk, and measures an electrical characteristic of the recording head, comprising the steps of: a) providing an optically transparent substrate; b) applying a magnetic material to a portion of said optically transparent substrate. ### Claim 7 (depends on 6) The method as recited in claim 6, wherein said magnetic material is applied to an inner portion of said optically transparent substrate.