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出願の表示

1. EP2518472 - OPTICAL IMAGE MEASUREMENT DEVICE

注意: このテキストは、OCR 処理によってテキスト化されたものです。法的な用途には PDF 版をご利用ください。

[ EN ]
Claims

1. An optical image measurement apparatus comprising:

an interferometer that splits low-coherence light into signal light and reference light and generates interference light by superposing the signal light that has passed through a measured object and the reference light that has passed through a reference optical path;

a light guiding part that guides the generated interference light;

a spectral part that divides the interference light emitted from an emission end of the light guiding part into spectra;

a light-receiving part that receives the interference light divided into spectra and outputs a signal;

a specifying part that specifies a received-light amount of the interference light by the light-receiving part based on the output signal;

a first changing part that changes the relative position between the emission end and a light-receiving surface of the light-receiving part;

a second changing part for changing the light amount of the interference light projected onto the light-receiving part;

a controller that controls the first changing part and the second changing part based on the specified received-light amount and leads the received-light amount of the interference light by the light-receiving part to a target value; and

an image forming part that forms an image of the measured object based on the results of the interference light received by the light-receiving part after the received-light amount has been led to the target value.


  2. The optical image measurement apparatus according to Claim 1, wherein the controller controls the first changing part based on the received-light amount specified by the specifying part and changes the relative position to increase the received-light amount.
  3. The optical image measurement apparatus according to Claim 1, wherein:

the light-receiving part is a line sensor that has multiple light-receiving elements arranged one-dimensionally; and

the first changing part changes the relative position by moving the emission end and/or the light-receiving part in a direction intersecting the direction of the arrangement of the multiple light-receiving elements.


  4. The optical image measurement apparatus according to Claim 1, wherein the second changing part comprises:

a shielding member that shields part of the cross-section of the low-coherence light, the signal light, the reference light and/or the interference light; and

a drive part that moves the shielding member; and

wherein, the controller controls the drive part based on the received-light amount specified by the specifying part and moves the shielding member to change a shield region in the cross-section.


  5. The optical image measurement apparatus according to Claim 1, wherein the controller causes the following operations to be performed alternately:

a first operation that controls the first changing part and the second changing part with reference to the received-light amount that is sequentially specified by the specifying part and changes the relative position to increase the received-light amount to at least an upper limit in a predefined range; and

a second operation that changes the light amount to decrease the received-light amount to at least a lower limit in the predefined range,

when the specified received-light amount decreases in response to a change in the relative position in the first operation, the controller causes the first changing part to perform a third operation that changes the relative position to the immediately preceding status of this change; and

further the controller causes the second changing part to perform a fourth operation that changes the light amount and leads the received-light amount to the target value.


  6. The optical image measurement apparatus according to Claim 5, wherein the controller in the first operation causes the following operations to be performed alternately until the received-light amount above the upper limit is specified by the specifying part:

an operation that causes the first changing part to change the relative position in a predefined direction by a predefined distance; and

an operation that causes the specifying part to specify the received-light amount.


  7. The optical image measurement apparatus according to Claim 5, wherein the controller in the second operation causes the following operations to be performed alternately until the received-light amount below the lower limit is specified by the specifying part:

an operation that causes the second changing part to decrease the light amount by a predefined amount; and

an operation that causes the specifying part to specify the received-light amount.


  8. The optical image measurement apparatus according to Claim 5, wherein the controller in the third operation causes the first changing part to change the relative position to the immediately preceding status in a direction opposite to the predefined direction.
  9. The optical image measurement apparatus according to Claim 1, wherein the controller:

with reference to the received-light amount that is sequentially specified by the specifying part, by controlling the first changing part and changing the relative position in a predefined direction, detects the peak of the specified received-light amount;

controls the first changing part in response to the peak being detected, and changes the relative position to the position where the peak has been detected in a direction opposite to the predefined direction; and

further controls the second changing part and changes the light amount to lead the received-light amount to the target value.


  10. The optical image measurement apparatus according to Claim 1, wherein the controller:

with reference to the received-light amount that is sequentially specified by the specifying part, by controlling the first changing part and changing the relative position in a predefined direction, increases the received-light amount until reaching a limit value for the light-receiving part;

controls the first changing part and further changes the relative position in the predefined direction until the specified received-light amount becomes less than the limit value;

controls the first changing part and changes the relative position between the emission end and the light-receiving surface of the light-receiving part to a third relative position between a first relative position where the received-light amount reaches the limit value and a second relative position where it becomes less than the limit value;

controls the second changing part and changes the light amount to lead the received-light amount to the target value.


  11. The optical image measurement apparatus according to Claim 10, wherein the third relative position is an intermediate position between the first relative position and the second relative position.
  12. The optical image measurement apparatus according to Claim 10, wherein the controller, in the operation leading the received-light amount to the target value, controls the second changing part with reference to the received-light amount that is sequentially specified by the specifying part.
  13. The optical image measurement apparatus according to Claim 10, wherein the controller:

based on an interval between the first relative position and the second relative position, calculates the amount of change in the light amount for changing the specified received-light amount from the limit value to the target value; and

in the operation leading the received-light amount to the target value, controls the second changing part to change the light amount by the calculated amount of change.