Canon Kabushiki Kaisha

Atsushi Maeda

Hitoshi Iijima

A rotary stage is controlled to two measurement positions along a rotational direction in which an object surface is moved when detecting a wavefront of reflected light from partial regions by a detector, to move the object surface. Respective placement errors in a trajectory of the object surface at the two measurement positions are measured based on wavefronts detected by the detector in states in which the rotary stage is controlled to each of the two measurement positions. For the remaining measurement positions among the measurement positions, respective placement errors with respect to the trajectory of the object surface are estimated based on the placement errors measured. Before measurement of each item of partial shape data, the rotary stage is controlled to a measurement position and stages are controlled to a position that cancels a placement error at the measurement position to align the object surface.

Shape measuring method, shape measuring apparatus, program, recording medium, method of manufacturing optical element, and optical element

A lens array includes a plurality of lenses that collect divided test light and form spots. Each lens includes a lens member, and a light shielding mask provided concentric to the lens member along a perimeter edge thereof, the light shielding mask shielding a part of the light and transmitting a part of the light. The light shielding mask is formed to satisfy a predetermined mathematical condition of light transmission.

Lens array, wavefront sensor, wavefront measurement apparatus, shape measurement apparatus, aberration measurement apparatus, manufacturing method of optical element, and manufacturing method of optical device

A wavefront measurement method includes the steps of causing object light to be incident on a Shack-Hartmann sensor, capturing a first spot image under image pickup conditions, calculating data of first spot positions that correspond to the first spot image, calculating second spot positions by simulating a second spot image on the basis of the image pickup condition and information of a travelling direction of diffracted light generated when the object light passes through the microlenses, and reducing detection errors of the spot positions by correcting the data of the first spot positions on the basis of data of the second spot positions including data of a detection error due to the diffracted light.

Wavefront measurement method, shape measurement method, optical element manufacturing method, optical apparatus manufacturing method, program, and wavefront measurement apparatus

To eliminate influence of undesirable light component from an object when measuring optical characteristics such as shape and wavefront aberration of the object, light from light source () is separated by polarization beam splitter () into measuring light (L) that irradiates and travels via the object () and is condensed on image plane (P) through microlenses () of microlens array (), and reference light (L) that does not irradiate the object and is guided to the image plane by reference light optical system (). A computer () acquires picked-up images sequentially from CCD image sensor () arranged on the image plane while changing optical path length of the reference light by movable stage (), extracts interference light spots generated through interference between signal light component and the reference light from the picked-up images, calculates positions of the interference light spots, and calculates deviation amounts of positions from predetermined reference positions.

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Utsunomiya, Japan

Atsushi Maeda