	US 7,525,085 B2
	Multi-axis optical encoders
Saiful Bahari Saidan, Bayan Lepas (Malaysia); Theng Hooi Yeoh, Penang (Malaysia); Chiang Sun Cheah, Butterworth (Malaysia); Jiin Cheang Cheong, Bayan Baru (Malaysia); and Chin Heong Yeoh, Bukit Mertajam (Malaysia)
Assigned to Avago Technologies General IP (Singapore) Pte. Ltd., Singapore (Singapore)
Filed on Apr. 14, 2006, as Appl. No. 11/403,999.
Prior Publication US 2007/0241270 A1, Oct. 18, 2007
Int. Cl. G01D 5/34 (2006.01)

U.S. Cl. 250—231.13

18 Claims

1. An optical encoding apparatus for the detection of position and/or motion of a mechanical device, the apparatus comprising:

a codescale;

an encoder housing having one or more portions;

a light-detecting sensor embedded within the encoder housing; and

a processing device linked to the light-detecting sensor and configured to determine an amount of light received by each light-detection element, the processing device being configured to determine at least one of a linear offset and an angular offset of the codescale with respect to the encoder housing based on signals received from the light-detecting sensor, wherein the light-detecting sensor is capable of sensing a pattern produced by the codescale superimposed on the light-detecting sensor, and wherein the light-detecting sensor includes a two-dimensional array of light detection elements having dimensions n-by-m where n and m are both integers greater than 4, a vertical dimension of the two-dimensional array of light detection elements being longer than a corresponding vertical dimension of the pattern produced by the codescale so that some of the light detection elements along the vertical dimension of the two-dimensional array are not affected by the pattern on the light-detecting sensor when the codescale is displaced with respect to the encoder housing, the vertical dimension being the dimension along a direction orthogonal to the moving direction of the codescale relative to the encoder housing.