JP2009168795A - Polarization detecting device, polarization detecting element, and polarization detecting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polarization detecting device capable of measuring two-dimensional distribution of phase difference and optical axis azimuth of a detected object in a wide range, with high accuracy and in a short time. <P>SOLUTION: The polarization detecting device 30 comprises a detecting optical means 1 provided with a polarizer array 7 and a TDI image sensor 5; a computing means 2; and a scanning stage 3. The polarizer array 7 comprises polarizers having mutually different transmission axis angles within a predetermined angle range, in each stage when four stages comprising polarizers 8 aligned in an integrating direction of the TDI image sensor are aligned in a direction perpendicular to the integrating direction to form one group, and has a plurality of such groups along the perpendicular direction. The TDI image sensor has a light receiving element for receiving light transmitted through each polarizer 8 of the polarizer array 7. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a polarization detection device, a polarization detection element, and a polarization detection method. Specifically, for example, a two-dimensional distribution of a phase difference or an optical axis direction of a transparent substance can be measured from the transmitted light in a short time. The present invention relates to a polarization detection device, a polarization detection element, and a polarization detection method.

  The liquid crystal display functions as a display device by changing luminance information by changing the polarization state of transmitted light according to the orientation direction of liquid crystal molecules. Therefore, the orientation direction of the liquid crystal molecules is one of the factors that determine the quality of the display device. In addition, the plurality of films constituting the panel are isotropic or anisotropic with a minute phase difference. However, unnecessary anisotropy is generated in the film or substrate due to strain or stress, and in the liquid crystal display, image quality performance is deteriorated due to poor alignment of liquid crystal molecules. Therefore, it is necessary to evaluate and inspect whether the film process, the substrate, and the liquid crystal display have the required retardation in the manufacturing process and the assembly process using those materials, and whether the alignment state of the liquid crystal molecules is appropriate. Therefore, a device for this is required.

  For example, there is a device as shown in Patent Document 1 as the above device. This detects the polarization state of the entire light beam using a two-dimensionally arranged CCD light receiving element.

As another example of the apparatus, there is the one shown in Patent Document 2. In this method, a polarizer array is attached to an area sensor to detect a polarization state.
Japanese Patent Laid-Open No. 10-293065 (published November 4, 1998) JP 2007-263593 (released on October 11, 2007)

  However, in any of the above-described conventional techniques, it is difficult to detect a wide range with high measurement accuracy and at high speed.

  Specifically, in the apparatus of Patent Document 1, it is necessary to insert / remove an optical element for detection during measurement, and high-speed detection cannot be realized. In addition, since the size of the CCD light receiving element is defined, a wide range cannot be detected at a time.

  In addition, the apparatus of Patent Document 2 has a problem that noise is increased because the number of measurement light-receiving elements at one point is small (16 × 4 × 4). Further, even if the number of light receiving elements is increased, there is a problem that the measurement resolution becomes rough. Furthermore, when an area sensor is used as the light receiving element, imaging is performed while moving in steps to perform a wide range of detection, and a plurality of captured images are processed, which takes a long time. Time detection is not possible. Further, Patent Document 2 describes that a line sensor can be used as a light receiving element. However, even if diverted to the polarizer array of Patent Document 2, the number of measurement light receiving elements at one point is the same. If 16 pieces are necessary, since one point is detected at intervals of 16 elements, the resolution becomes coarse. Further, if the number of measurement light receiving elements at one point is reduced, noise increases. Furthermore, a photonic crystal is used for the polarizer array, but this has a narrow operating wavelength band. Therefore, when used in a liquid crystal panel or the like, in order to correspond to all wavelengths of R (red), G (green), and B (blue), it is necessary to prepare sensors corresponding to the respective wavelength ranges. There is a problem that the number increases.

  Therefore, the present invention has been made in view of the above-described problems, and its purpose is to provide a wide range and high-level two-dimensional distribution of the phase difference and optical axis orientation of a detection target (for example, a liquid crystal panel). The present invention provides a polarization detecting device that can measure with accuracy and in a short time.

A first polarization detecting device for detecting a polarization state of a detection object according to the present invention is a polarization detection device for detecting the polarization state of a detection object in order to solve the above-described problem. ,
A phaser array composed of a plurality of phasers, a polarizing plate, and an image sensor that receives light emitted from the detected object and transmitted through the phaser and the polarizing plate are provided. Detection optical means, and calculation means for calculating polarization information of the detected object from the output of the image sensor, and the number of the phaser arrays is R (where R is an integer of 2 or more). A plurality of phase shifters having different fast axis angles within a predetermined angle range are provided in one stage in which the phase shifters are aligned.

  As described above, in the first polarization detection device according to the present invention, the phaser array has a predetermined stage in one stage in which R (where R is an integer of 2 or more) phase-arrays are aligned. Since there are a plurality of the above-mentioned phase shifters having different fast axis angles within the angle range, for example, by using a time delay integration type image sensor as the image sensor, the phase difference or optical axis direction of the detected object Thus, it is possible to provide a polarization detector capable of measuring the two-dimensional distribution in a wide range, with high accuracy and in a short time.

  The time delay integration type image sensor has a plurality of light receiving elements arranged in the integration direction. For example, assuming that 50 light receiving elements are arranged in the integration direction, one area of the detection object is measured by 50 light receiving elements by continuous movement. That is, information obtained by measuring one area of the detected object 50 times and integrating the same can be obtained. Therefore, the first polarization detection device of the present invention can contribute to the realization of detection with low noise and high measurement resolution.

  More specifically, in the first polarization detection device according to the present invention, the image sensor is a time delay integration type image sensor, and the polarization detection device is along an integration direction of the time delay integration type image sensor. A scanning stage for relatively moving the time delay integration type image sensor and the detection object, and the alignment direction of the phase shifters constituting the stage is the integration direction of the time delay integration type image sensor. It is preferable that it is along.

  In addition, a wide range can be measured in a short time by relatively moving the time delay integration type image sensor and the detected object.

  The above-mentioned “regions having different fast axis angles within a predetermined angle range” means, for example, from one end of the step within an angle range from 0 ° to 45 ° as described later. The region aligned to the other end is aligned so that the angle from the reference axis sequentially increases (or decreases) such as 0 °, 3.75 °, 7.5 °, 11.25 °, 15 °. In addition to the case where the angle is set, from one end of the step, the order of the angles is not limited, such as 3.75 °, 0 °, 7.5 °, 15 °, 11.25 °, etc. This includes cases where they are aligned.

  In addition to the above-described configuration, the first polarization detection device according to the present invention includes N one stage in the direction perpendicular to the alignment direction of the phasers constituting the one stage (however, , N is an integer greater than or equal to 4) When the above-described retarder array composed of R × N regions configured side by side is formed as one set, the above-described retarder array includes a plurality of the above-described sets in the vertical direction. The above-mentioned set of L (L is any integer from 1 to N) stages of the above phaser array is (L-1) × 180 ° / N to L × 180 ° with reference to the reference axis. It is preferable to include the above-described regions having different fast axis angles within an angle range up to / N. In this regard, in other words, the region in which the pair of the phaser arrays has different fast axis angles within an angle range from 0 ° to 1 × 180 ° / N with respect to the reference axis. The first stage including the second stage, and the second stage including the regions having different fast axis angles within an angle range from 1 × 180 ° / N to 2 × 180 ° / N with respect to the reference axis. The Nth stage including the above-described region having the different fast axis angles within an angle range of (N-1) × 180 ° / N to 180 ° with respect to the reference axis. It is preferable to consist of.

  By adopting the above configuration, the first polarization detection apparatus according to the present invention can realize detection with high measurement accuracy.

  In the first polarization detection device according to the present invention, the set of the phaser arrays has different fast axis angles within an angle range from 0 ° to 45 ° with respect to the reference axis. A first stage including the area; a second stage including the area having different fast axis angles within an angle range of 45 ° to 90 ° with respect to the reference axis; A third stage including the region having different fast axis angles within an angle range of 90 ° to 135 ° with respect to the axis; and an angle of 135 ° to 180 ° with respect to the reference axis It is more preferable that the fourth stage includes the above-described region having different fast axis angles within the range.

  By adopting the above configuration, the first polarization detection device according to the present invention realizes a high measurement resolution as compared with the case where the set of the phaser arrays is configured of five or more stages. be able to.

  For example, if one element of TDI is 10 × 10 μm and the optical system is one-to-one, the resolution is 40 μm if one point can be measured in four stages. On the other hand, if 16 stages are required, the resolution will be 160 μm, so a high measurement resolution can be achieved with a configuration that measures one point in 4 stages.

  Further, in the above configuration, the calculation means includes the output based on the light received at the first stage, the output based on the light received at the second stage, and the third It is preferable to calculate the polarization information of the detection object based on the output based on the light received at the stage and the output based on the light received at the fourth stage.

  However, the present invention is not limited to the above-described four-stage configuration, and may have the following five-stage configuration. That is, in the first polarization detecting device according to the present invention, the set of the phaser arrays has different fast axis angles within an angle range from 0 ° to 36 ° with respect to the reference axis. A first stage including the phaser, and a second stage including the phaser having a different fast axis angle within an angle range of 36 ° to 72 ° with respect to a reference axis. A third stage including the phaser having a different fast axis angle within an angle range of 72 ° to 108 ° with respect to the reference axis; and 108 ° to 144 ° with respect to the reference axis. 4th stage including the above phaser having different fast axis angles within the angle range up to, and different fast axis within the angle range from 144 ° to 180 ° with reference to the reference axis And may comprise a fifth stage including the phaser having an angle. .

  Further, in the five-stage configuration, the calculation means includes the output based on the light received in the first stage, the output based on the light received in the second stage, and the first Based on the output based on the light received at the third stage, the output based on the light received at the fourth stage, and the output based on the light received at the fifth stage. Thus, it is preferable to calculate the polarization information of the object to be detected.

  In the first polarized light detection apparatus according to the present invention, in addition to the above configuration, the phaser array preferably has a periodic uneven structure.

  Since a normal phase shifter is made of a natural crystal such as quartz, it cannot have a distribution in the direction of the fast axis. However, according to the above-described configuration of the present invention, since the concavo-convex structure is provided, it can be manufactured by controlling the direction of the fast axis, and can be distributed in the direction of the fast axis. .

  In addition to the above-described configuration, the first polarization detector according to the present invention has a periodic concavo-convex structure formed on one surface, and the other surface or one surface of the phaser array. It is preferable that the function of the polarizing plate is realized by forming a wire grid on the top.

  By adopting the above configuration, the function of the polarizing plate can be realized (manufactured) directly on the back of the phaser array with a wire grid compared to the configuration in which the phased array and the polarizing plate are installed separately. Since only one optical element is required, the amount of transmitted light can be secured and the apparatus can be made compact.

  In the above configuration, the phaser array may be a liquid crystal panel.

  The phaser array may be composed of a plurality of phasers having different phase advance axis angles within a predetermined angle range, and any of the phasers constituting the stage is different from each other. It may have an axial angle.

  In addition, the second polarization detection device for detecting the polarization state of the detection object according to the present invention is a polarization detection device for detecting the polarization state of the detection object in order to solve the above-described problem. And a detection optical means provided with a polarizer array constituted by a plurality of polarizers, and an image sensor that receives the light emitted from the detection object and transmitted through the polarizer, And calculating means for calculating the polarization information of the detection object from the output of the image sensor, and the polarizer array has R (where R is an integer of 2 or more) polarizers aligned. Each stage has a plurality of the polarizers having different transmission axis angles within a predetermined angle range.

  As described above, in the second polarization detection device according to the present invention, the polarizer array has a predetermined stage in one stage formed by arranging R polarizers (where R is an integer of 2 or more). Since it has a plurality of polarizers having different transmission axis angles within the angle range, by using, for example, a time delay integration type image sensor as an image sensor, the phase difference of the detected object and the optical axis direction It is possible to provide a polarization detecting device capable of measuring a two-dimensional distribution in a wide range, with high accuracy and in a short time.

  The time delay integration type image sensor has a plurality of light receiving elements arranged in the integration direction. For example, assuming that 50 light receiving elements are arranged in the integration direction, one area of the detection object is measured by 50 light receiving elements by continuous movement. That is, information obtained by measuring one area of the detected object 50 times and integrating the same can be obtained. Therefore, the second polarized light detection apparatus of the present invention can contribute to the realization of detection with low noise and high measurement resolution.

  More specifically, in the second polarization detection device according to the present invention, the image sensor is a time delay integration type image sensor, and the polarization detection device is along an integration direction of the time delay integration type image sensor. A scanning stage for relatively moving the time delay integration type image sensor and the detection object, and the alignment direction of the polarizers constituting the stage is the integration direction of the time delay integration type image sensor. It is preferable that it is along.

  In addition, a wide range can be measured in a short time by relatively moving the time delay integration type image sensor and the detected object.

  The “region having transmission axis angles different from each other within a predetermined angle range” means, for example, from one end of the step to the other within an angle range of 0 ° to 45 ° as described later. The regions aligned up to the end of each are aligned so that the angle from the reference axis sequentially increases (or decreases) such as 0 °, 3.75 °, 7.5 °, 11.25 °, 15 °. In addition to the case, the angle is arranged from one end of the above steps regardless of the order of the angle, such as 3.75 °, 0 °, 7.5 °, 15 °, 11.25 °, etc. This includes cases where

  In addition to the above-described configuration, the second polarization detection apparatus according to the present invention includes N one stage in the direction perpendicular to the alignment direction of the polarizers constituting the one stage (however, , N is an integer of 4 or more) When the polarizer array composed of R × N regions arranged side by side is made into one set, the polarizer array has a plurality of the sets in the vertical direction. The above-mentioned set of L (L is any integer from 1 to N) stages of the polarizer array is (L-1) × 180 ° / N to L × 180 ° with reference to the reference axis. It is preferable to include the above-described regions having different transmission axis angles within an angle range up to / N. In this regard, in other words, the set of the phaser arrays includes the regions having different transmission axis angles within an angle range from 0 ° to 1 × 180 ° / N with respect to the reference axis. The second stage including the first stage and the region having different transmission axis angles within an angular range from 1 × 180 ° / N to 2 × 180 ° / N with respect to the reference axis And Nth stage including the above-described regions having different transmission axis angles within an angle range of (N−1) × 180 ° / N to 180 ° with reference to the reference axis. It is preferable.

  By adopting the above configuration, the second polarization detection device according to the present invention can realize detection with high measurement accuracy.

  In addition to the above-described configuration, the second polarized light detection device according to the present invention is configured such that the set of the polarizer arrays has different transmission axes within an angle range from 0 ° to 45 ° with respect to the reference axis. A first stage including the region having an angle; and a second stage including the region having a transmission axis angle different from each other within an angle range of 45 ° to 90 ° with respect to the reference axis. The third stage including the stage, the third area including the transmission axis angles different from each other within an angle range of 90 ° to 135 ° with respect to the reference axis, and 135 ° to 180 ° with respect to the reference axis. It is preferable to include the fourth step including the region having transmission axis angles different from each other within an angle range of up to °.

  By adopting the above configuration, the second polarization detection device according to the present invention realizes a high measurement resolution as compared with the case where the set of the polarizer arrays is composed of five or more stages. be able to.

  For example, if one element of TDI is 10 × 10 μm and the optical system is one-to-one, the resolution is 40 μm if one point can be measured in four stages. On the other hand, if 16 stages are required, the resolution will be 160 μm, so a high measurement resolution can be achieved with a configuration that measures one point in 4 stages.

  Further, in the second polarization detecting device according to the present invention, in addition to the above configuration, the calculating means receives the output based on the light received at the first stage and the light received at the second stage. Based on the output based on the received light, the output based on the light received at the third stage, and the output based on the light received at the fourth stage. It is preferable to calculate polarization information of the body.

  However, the present invention is not limited to the above-described four-stage configuration, and may have the following five-stage configuration. That is, in the second polarization detecting device according to the present invention, the set of the polarizer arrays has different transmission axis angles within an angle range from 0 ° to 36 ° with respect to the reference axis. A first stage including a phaser; a second stage including the phaser having different transmission axis angles within an angle range from 36 ° to 72 ° with respect to a reference axis; and a reference A third stage including the phaser having different transmission axis angles within an angular range of 72 ° to 108 ° with respect to the axis, and an angle of 108 ° to 144 ° with respect to the reference axis; In the range, the fourth stage including the phaser having different transmission axis angles, and in the angle range from 144 ° to 180 ° with respect to the reference axis, having different transmission axis angles. The fifth stage including the above phaser .

  Further, in the five-stage configuration, the calculation means includes the output based on the light received in the first stage, the output based on the light received in the second stage, and the first Based on the output based on the light received at the third stage, the output based on the light received at the fourth stage, and the output based on the light received at the fifth stage. Thus, it is preferable to calculate the polarization information of the object to be detected.

  Moreover, in addition to said structure, the 2nd polarization | polarized-light detection apparatus which concerns on this invention is the said polarizer array, The said polarizer array forms a polarization function by forming a wire grid in the one surface of a board | substrate. It is preferable that it is realized.

  The polarizer array may be composed of a plurality of polarizers having different transmission axis angles within a predetermined angle range, and any of the polarizers constituting the stage has different transmission axis angles. You may do it.

  The present invention also includes the following first detection optical element. That is, the first detection optical element according to the present invention is a detection optical element provided in the polarization detection device for detecting the polarization state of the detection target, and the detection optical elements include R (however, R Is a phaser array having a plurality of the above phaser having different fast axis angles within a predetermined angle range in one stage formed by aligning two or more phasers). It is characterized.

  The present invention also includes the following second detection optical element. That is, the first detection optical element according to the present invention has different fast axes within a predetermined angle range in one stage in which R (where R is an integer of 2 or more) polarizers are aligned. It is a polarizer array having a plurality of polarizers having an angle.

  According to these first and second polarization detecting elements, it is possible to measure a two-dimensional distribution of a phase difference and an optical axis direction of a detection target (for example, a liquid crystal panel) in a wide range, with high accuracy and in a short time. it can.

  The present invention also includes the following first polarization detection method. That is, the first polarization detection method according to the present invention is a polarization detection method for detecting the polarization state of the detection object, and the light emitted from the subject is different in phase within a predetermined angle range. After passing through a phaser array having a plurality of phasers having an axial angle, the light transmitted through the polarizing plate and transmitted through the polarizing plate is received by the image sensor and output from the image sensor. Is input to the calculation means for calculating the polarization information of the detection object, and the polarization state of the detection object is detected.

  The present invention also includes the following second polarization detection method. That is, the second polarization detection method according to the present invention is a polarization detection method for detecting the polarization state of the detection object, and the light emitted from the subject is different in phase within a predetermined angle range. The light transmitted through the polarizer array having a plurality of polarizers having an axial angle and transmitted through the polarizer array is received by the image sensor, and the output from the image sensor is converted into the polarization of the detected object. It is characterized in that it is inputted to a calculation means for calculating information and the polarization state of the detection object is detected.

  According to these first and second polarization detection methods, the two-dimensional distribution of the phase difference and the optical axis direction of the detection target (for example, a liquid crystal panel) can be measured over a wide range, with high accuracy and in a short time. it can.

  As described above, the first polarization detection apparatus according to the present invention includes a polarizer array constituted by a plurality of regions having transmission axes, and light emitted from the detected object, the polarizer array A detection optical means provided with a time delay integration type image sensor for receiving light transmitted through the time delay, and from the output of the time delay integration type image sensor based on the light received by the time delay integration type image sensor. A calculation unit for calculating polarization information of a detector; and a scanning stage for continuously moving and scanning the detection optical unit along the integration direction of the time delay integration type image sensor. R stages (where R is a plurality) arranged in the integration direction of the time-delay integration type image sensor in the direction perpendicular to the integration direction (where N is 4 or more). (Integer) When the array of R × N regions is set as one set, each of the stages is composed of the regions having different transmission axis angles within a predetermined angle range, and A plurality of the sets are provided along the vertical direction, and the time delay integration type image sensor includes a plurality of light receiving elements that receive light transmitted through the regions of the polarizer array. It is characterized by that. In addition, as described above, the second polarization detection device according to the present invention includes a phaser array constituted by a plurality of regions having a fast axis, a polarizing plate, and light emitted from the detected object. And a detection optical means provided with a time delay integration type image sensor for receiving light transmitted through the phaser array and the polarizing plate, and the time based on the light received by the time delay integration type image sensor. A calculation stage for calculating the polarization information of the detected object from the output of the delay integration type image sensor, and a scanning stage for continuously moving and scanning the detection optical means along the integration direction of the time delay integration type image sensor The phaser array includes R stages (where R is a plurality) aligned in the integration direction of the time delay integration type image sensor, and the stage is perpendicular to the integration direction. When the array composed of R × N areas is arranged as a set by aligning N in the direction (where N is an integer of 4 or more), each of the above stages has a different progression within a predetermined angle range. A plurality of the sets are provided along the vertical direction, and the time delay integration type image sensor transmits each of the regions of the polarizer array. It has a plurality of light receiving elements for receiving light. In addition, as described above, the first detection optical element according to the present invention includes a polarizer array configured by a plurality of regions having transmission axes, and light emitted from the detected object, The time delay integration type image sensor that receives light transmitted through the child array, and the polarizer array and the time delay integration type image sensor are integrally moved and scanned along the integration direction of the time delay integration type image sensor. The polarizer array includes R stages (where R is a plurality) aligned in the integration direction of the time delay integration type image sensor in the integration direction. When N (where N is an integer of 4 or more) are aligned in a vertical direction and the array of R × N regions is combined into one set, each of the above stages is within a predetermined angle range. Different A plurality of the sets are provided along the vertical direction, and the time delay integration type image sensor transmits each of the regions of the polarizer array. It is characterized by having a plurality of light receiving elements for receiving the received light. Further, as described above, the second detection optical element according to the present invention is a plurality of second detection optical elements provided in the polarization detection device for detecting the polarization state of the detection target, having a fast axis. A phase delay array configured by the region, a polarizing plate, and a time delay integration type image sensor that receives light emitted from the detected object and transmitted through the phase shifter array and the polarizing plate; A scanning stage for continuously moving and scanning the phaser array, the polarizing plate and the time delay integration type image sensor along the integration direction of the time delay integration type image sensor. The phaser array has R stages (where R is a plurality) aligned in the integration direction of the time-delay integration type image sensor in the direction perpendicular to the integration direction. When the array of R × N regions is aligned to form one set, each of the stages is composed of the regions having different fast axis angles within a predetermined angle range. In addition, a plurality of the sets are provided along the vertical direction, and the time delay integration type image sensor has a plurality of light receiving elements that receive light transmitted through the regions of the polarizer array. It is characterized by that.

  With the above configuration, the two-dimensional distribution of the phase difference and optical axis direction of the detection target can be measured over a wide range, with high accuracy, and in a short time.

[Embodiment 1]
An embodiment of the present invention will be described with reference to FIGS. In the following description, various technically preferable limitations for carrying out the present invention are given, but the scope of the present invention is not limited to the following embodiments and drawings.

  FIG. 1 shows a configuration of a polarization detecting device 30 according to the present invention. The polarization detection device 30 is connected to calculation processing means 2 (calculation means) that calculates the polarization state based on the output from the detection optical means 1. The detection optical means 1 is fixed to the scanning stage 3. The sample 4 (object to be detected) is installed on the front surface of the detection optical means 1.

  FIG. 2 shows a specific configuration of the detection optical means 1. As shown in FIG. 2, the detection optical means 1 includes a time delay integration (TDI) image sensor 5 and a polarizer array 7 on the front surface thereof.

  The output of the TDI image sensor 5 is sent to the calculation processing means 2 that calculates the polarization state. In FIG. 2, the TDI image sensor and the polarizer array 7 are installed apart from each other, but may be installed in close contact. The polarization detector can be made compact by installing it closely.

  Here, the TDI image sensor 5 will be described. In the TDI image sensor 5, one-dimensional data obtained by imaging the same place by the sensors in the adjacent columns (second column) is added to the one-dimensional data acquired by the light receiving elements in the first column. This is repeated one by one for the number of TDI columns. Therefore, if the scanning speed of the TDI sensor is the same as that of the line sensor, an imaging result can be obtained in which the exposure time is increased by twice the number of TDI sensor columns compared to the exposure time of the line sensor. For example, the one-dimensional data obtained by imaging the same part in the column a2 is added to the one-dimensional data captured by the column a1 illustrated in FIG. Further, one-dimensional data obtained by imaging the same part is added to the column a3. If the integrated speed and the scanning speed of the sample 4 are set equal in this way, one piece of image data can be acquired.

  In FIG. 1, the entire measurement surface of the sample 4 is detected by scanning in the X-axis direction (the integration direction of the TDI image sensor 5) shown in the figure, which is a direction parallel to the measurement surface of the sample 4, with the scanning stage 3. Can do. In FIG. 1, the detection optical means 1 is fixed on the scanning stage 3 and scanned. However, since the detection optical means 1 and the sample 4 only need to move relative to each other, the detection optical means 1 is fixed and the sample 4 is moved to the scanning stage 3. The detection optical means 1 and the sample 4 may be configured to move using scanning means (not shown). Moreover, it is not limited to continuous movement, and may be step movement.

  Next, the polarizer array 7 will be described. FIG. 3 shows a configuration of a polarizer (a region of a polarizer array). Reference numeral 8 in FIG. 3 denotes a polarizer. Assume that light having a component oscillating in the X-axis direction and the Z-axis direction is incident on the polarizer 8. Assume that the transmitted light has only a component that vibrates in the X-axis direction. Such an element that transmits or does not transmit light depending on the vibration direction is called a polarizer. When only a component that vibrates in the Z-axis direction passes through the polarizer 8 as in the polarizer 8, the Z-axis direction is referred to as the transmission axis direction of the polarizer 8.

  In this way, the polarizer array 7 is obtained by arranging the optical functions such as the polarizer 8 in an array.

  The polarizer array 7 is manufactured so that the transmission axis directions shown in FIG. 3 are different in each array. The transmission axis of each polarizer will be described next.

  FIG. 4 is a schematic view showing the transmission axis directions of the polarizer array 7. The direction of the arrow written on each polarizer of the polarizer array 7 indicates the direction of the transmission axis. The transmission axis continuously changes in the X-axis direction of the element, that is, the direction in which the TDI image sensor 5 integrates the detected luminance. Step b1 (first step) in FIG. 4 sets the Z axis (reference axis) to 0 ° from 0 ° to 45 °, and step b2 (second step) sets the Z axis (reference axis) to 0 °. From 45 ° to 90 °, the step b3 (third step) takes the Z axis (reference axis) as 0 °, and the step b4 (fourth step) takes the Z axis (reference axis). ) Is 0 °, and polarizers 8 having different angles of transmission axes are arranged in an angle range of 135 ° to 180 °. Below the step b4, the direction of the transmission axis is not shown, but the step b1, the step b2, the step b3, and the step b4 are set as a set, and a plurality of sets are arranged.

  Regarding the optical positional relationship between the polarizer array 7 and the TDI image sensor 5, each array of the polarizer array 7 corresponds to each light receiving element of the TDI image sensor 5. That is, the light transmitted through each array of the polarizer array 7 is arranged so as to be detected by each light receiving element. Further, each stage such as the stages b1 and b2 is arranged so as to coincide with the integration direction of the detected luminance of the TDI image sensor 5. In FIG. 4, it is preferable that the number of polarizer arrays 7 is equal to the number of light receiving elements of the TDI image sensor 5. For this reason, in FIG. 4, the number of divisions of each stage of the polarizer array 7 is indicated by 12, but is not limited thereto. Also, the number of divisions in the Z-axis direction is not limited to the number of divisions as shown in FIG. 4, and is preferably the same as the number of light receiving elements of the TDI image sensor 5.

  A method for measuring the polarization state of the sample 4 (FIG. 1) using the polarization detection device 30 as described above will be described below. First, an example of the measurement method is shown, and then the measurement method of the present embodiment is described.

  FIG. 5 shows a schematic diagram of an optical system showing an example of polarization measurement. Polarization measurement is to obtain the characteristic information of the sample from the change of the Stokes parameter by obtaining the Stokes parameter of the sample transmitted light and transmitting the sample. The Stokes parameters are represented by S0, S1, S2, and S3 expressed by the following equations (1) to (4).

  Ex and Ez indicate the electric field amplitude of light in the X-axis direction and the Z-axis direction in FIG. 5, and Δ indicates the phase difference between Ex and Ez.

  Therefore, the Stokes parameter of the sample transmitted light is measured. FIG. 5 illustrates the transmitted light model. As an optical system, the light source 10, the polarizing plate 11, the quarter wavelength plate 12, the sample 13, the polarizing plate 14, and the detector 16 are arranged in this order. The light source 10 may be white light or monochromatic light, but the calculation is easier because the monochromatic light is analyzed by one wavelength. The light from the light source 10 passes through the polarizing plate 11 and the quarter-wave plate, becomes circularly polarized light, and enters the sample 13. The light incident on the sample 13 is circularly polarized light in FIG. 5, but may be linearly polarized light. In the case of entering linearly polarized light, the quarter wave plate 12 is not necessary. The light transmitted through the sample 13 passes through the polarizing plate 14 and its intensity is detected by the detector 16.

  As a measurement method, the intensity is detected while rotating the polarizing plate 14. When the rotation angle of the polarizing plate 14 is C, the detection intensity I (C) is expressed by the following equation (5).

Can be expressed as

  Here, I0 is the normalized strength, and normally I0 = 1. The coefficients α1 and α2 are represented by S0, S1, and S2 among the Stokes parameters (S0, S1, S2, and S3) of the transmitted light from the sample. Therefore, the coefficients α1 and α2 may be obtained. As a method of obtaining, there are a method of Fourier transforming the detected intensity I (C) and a method of obtaining from the integrated intensity as shown below.

When I1, I2, I3, and I4 are defined by the equation (6), α1 and α2 are expressed by the following equations (7) and (8).

It can be expressed as

  As described above, when the integrated intensities I1, I2, I3, and I4 are obtained from the detected intensities according to the equation (6), α1 and α2 are obtained, and the Stokes parameters S0, S1, and S2 of the transmitted light are obtained. it can. Although the Stokes parameter S3 is not found here, the magnitude of anisotropy that is physical information of the sample and its optical axis direction can be found without obtaining the value of S3. However, if S3 is not obtained, the range of the phase difference that can be detected is small.

  In the method shown in FIG. 5, since it is necessary to rotate the polarizing plate 14, the measurement cannot be performed for a short time. Therefore, the polarization detector 30 of this embodiment is used.

  In the polarization detection device 30 of the present embodiment, an element corresponding to the polarizing plate 14 in FIG. 5 corresponds to the polarizer array 7 in FIG. 4, and a detector 16 in FIG. 5 corresponds to the TDI image sensor 5 in FIG. In the method described with reference to FIG. 5, the rotation of the polarizing plate 14 corresponds to each transmission axis of each polarizer configured in each stage of the polarizer array 7 shown in FIG. Therefore, the light transmitted through each polarizer of the stage b1 in FIG. 4 is equivalent to the light when the polarizing plate 14 in FIG. 5 is rotated from 0 ° to 45 °. Therefore, in order to obtain the integral represented by the above equation (6), all the intensities of the light transmitted through the stage b1 in FIG. 4 may be added. Here, since the output of the TDI image sensor 5 is the sum of the outputs of the stage b1 that has detected the same location, it becomes the integral value itself. Actually, when the output of the stage b1 is B1 in the TDI image sensor 5, the integrated intensity I1 'corresponding to the equation (6) can be expressed by the following equation (9).

Here, δb is an angle difference of transmission axes between adjacent polarizers.

  As described above, assuming that the outputs from the stage b2, the stage b3, and the stage b4 are B2, B3, and B4, the integrated intensities I2 ′, I3 ′, and I4 ′ corresponding to the expression (6) are expressed by the following expression (10): ~ (12)

Can be expressed as

  From coefficients I1 ′, I2 ′, I3 ′, and I4 ′ obtained from Expressions (9) to (12), coefficients α1 and α2 of detected intensity I are calculated using Expressions (7) and (8), and the sample is transmitted. The Stokes parameters of light S0, S1, and S2 can be obtained. The Stokes parameter of the sample transmitted light is obtained by the calculation processing means 2. The calculation processing means 2 may be an apparatus main body that performs the above-described calculation, or causes the external computer to operate as the calculation processing means 2 by incorporating a program for performing the calculation as described above into the external computer. It may be a thing.

  In the polarization detection device 30 of the present embodiment, since there is no drive unit for rotating and inserting the optical element, measurement in a short time is possible. Further, since the output from the TDI image sensor 5 is the addition of intensity, the burden on the calculation processing means 2 is reduced and the calculation time is shortened. Furthermore, since the TDI image sensor is a scanning sensor, a wide range of measurements can be performed by scanning while imaging.

  The polarizer array that can be used in this embodiment is not limited to that shown in FIG. For example, it may be as shown in FIG. That is, in the polarizer array 7 shown in FIG. 4, the angles of the transmission axes of the polarizers constituting the stage b1 are continuously changed from one end to the other end of the stage b1. On the other hand, in the polarizer array 7 ′ shown in FIG. 6, the transmission axes of the polarizers constituting the stage b1 ′ are continuously angled from one end to the other end of the stage b1 ′. It has not changed. That is, the polarizer array that can be employed in this embodiment is configured so that one stage is composed of polarizers having different transmission axis angles within an angle range from 0 ° to 45 °. Good. Also, the arrangement in the column direction (direction perpendicular to the integration direction) is b1, b2, b3, and b4 in FIG. 4, but is not limited to this. As shown in FIG. 6, the order may be changed as b1 ', b2', b4 ', b3'.

  Further, it is not necessary to assign a polarizer array 7 having a different transmission axis direction (polarization axis angle) to each light receiving element of the TDI image sensor 5 as shown in FIG. In FIG. 7, a polarizer array having the same transmission axis direction is assigned to two light receiving elements in the integration direction. However, since the measurement accuracy improves when the transmission axis direction is assigned more finely, it is better to divide and detect as much as possible.

  The polarizer array 7 of this embodiment can be manufactured with a wire grid. The wire grid is a structure in which metal lines formed with a line width of several tens of nm and a pitch of one hundred and several tens of nm are arranged. As the metal, aluminum or the like can be mainly used. The polarizer array 7 may be formed by forming a wire grid on the surface of a substrate (for example, glass). In this element, the direction perpendicular to the line direction is the light transmission axis. A polarizer made of a wire grid has a higher transmittance than a normal polarizing plate. Since the direction of the metal line can be set freely, the transmission axis direction of the polarizer array can be set freely, which is suitable as the polarizer array of this embodiment. Moreover, since it operates as a polarizer in the entire visible light region, there is no need to select a detection wavelength.

  As described above, the polarization detection device 30 according to this embodiment includes the polarizer array 7 including the plurality of polarizers 8 having the transmission axis, and the light emitted from the sample 4, Detection optical means 1 provided with a TDI image sensor 5 for receiving the transmitted light, and a calculation process for calculating the polarization information of the sample 4 from the output of the TDI image sensor 5 based on the light received by the TDI image sensor 5 Means 2 and a scanning stage 3 for moving the detection optical means 1 relative to the sample along the integration direction of the TDI image sensor 5 are provided, and the polarizer array 7 is aligned in the integration direction of the TDI image sensor. When four stages of the 12 polarizers are aligned in a direction perpendicular to the integration direction and set as one set, each stage falls within a predetermined angular range as described above. And the TDI image sensor transmits the polarizers 8 of the polarizer array 7 through the polarizers 8. The TDI image sensor transmits the polarizers 8 of the polarizer array 7. A plurality of light receiving elements for receiving the received light. Thereby, it is possible to provide a polarization detecting device capable of measuring the phase difference and the two-dimensional distribution of the optical axis direction of the sample 4 in a wide range, with high accuracy and in a short time. As the TDI image sensor used in the present embodiment, for example, a sensor that integrates up to 96 stages can be used. However, the present invention is not limited to this, and it is more preferable to use a sensor that integrates more stages.

  In the present embodiment, the calculation processing means 2, the detection optical means 1, and the scanning stage 3 (detection optical element) may be configured separately.

  Further, in the present embodiment, a description has been given of a configuration in which all of the polarizers constituting each stage have different transmission axis angles, but the present invention is not limited to this. That is, some of the polarizers constituting a certain stage may have the same transmission axis angle. However, when there are polarizers with the same transmission axis angle in part, the integrated intensity value created by different angles gives a result different from the true value, so the detection accuracy deteriorates. However, as long as the detection accuracy is allowed to deteriorate, even if the same direction is partially included, it may be considered that there is no particular problem. Also, if you know the polarizer at the same angle in advance, you can subtract the detected intensity at that angle from the integrated intensity or discard it without adding it to the integrated intensity. Results similar to strength can be obtained.

  In the present embodiment, the configuration in which 0 ° to 180 ° is divided into four has been described, but the number of divisions may be four or more. Since there are four Stokes parameters (S0, S1, S2, S3), at least four stages are required. In other words, there is a method of detecting with higher accuracy by dividing b1 ', b2', b3 ', b4', b5 'by dividing into five. In this case, the polarizer array 7 is configured to measure one point in five stages.

  In the present embodiment, the stage b1, the stage b2, the stage b3, and the stage b4 shown in FIG. 4 are set as one set, and a plurality of sets are arranged below the stage b4. It is not limited to this. That is, when one point measurement is sufficient, the polarizer array may be only one set of the above-described four or five divisions, and if only one point is measured (ie, point measurement), scanning is performed in the first place. There is no need to do. On the other hand, line measurement (that is, line measurement) can be performed by configuring only one set and scanning this. As another method for realizing this line measurement, the above-mentioned one set from one stage is used. The line measurement can also be realized by providing a plurality of such sets. Further, as a method for measuring a wider range, that is, a two-dimensional region (ie, surface measurement), (1) one set is two-dimensionally scanned, and (2) one set is configured from one of the above stages. There is a configuration in which a plurality of such sets are provided and one-dimensional scanning is performed, or (3) a plurality of sets are provided with a plurality of stages as shown in FIG.

  Further, not only a wire grid element but also a polarizer array made of a photonic crystal may be used. When a photonic crystal is used, the operating bandwidth is as narrow as 50 nm, but a photonic crystal may be used if it can be limited to detection of a specific wavelength.

  Moreover, the polarization detection apparatus of this embodiment detected the polarization state of the sample transmitted light as shown in FIG. However, the present invention is not limited to this, and the same detection can be performed by detecting the polarization state of the sample reflected light. However, it should be noted that the relational expression between the coefficients α1 and α2 of the detection intensity I (C) and the physical property information of the sample is different. Also, when detecting the transmitted light of the sample, it is necessary to note that the physical property information is an integral value in the thickness direction of the sample. When detecting the reflected light from the sample, depending on the setting of the incident angle to the sample The physical property information on the sample surface is detected.

In other words, it can be said that the polarization detection apparatus according to the present embodiment is characterized by the following points. That is, the polarization detector is
(1) Detection optical means having a polarizer array having a plurality of polarizers having different transmission axis directions, a time delay integrating image sensor for detecting light transmitted through the polarizer array and the polarizing plate, and a time delay A calculation processing means for calculating polarization information from an output from the integration type image sensor and a scanning stage for scanning the detection optical means are provided, and light transmitted through each array of the polarizer array is received by each of the time delay integration type image sensors. The polarizer array is configured to include an area in which the transmission axis direction continuously changes in the integration direction of the time delay integration type image sensor. In other words, the transmission axis direction periodically changes in the direction perpendicular to the integration direction of the sensor. In (1),
(2) In the polarizer array, the first stage is an array in which the direction of the transmission axis is changed from 0 ° to 45 °, and the second stage is an array in which the direction of the transmission axis is changed from 45 ° to 90 °. The third stage is composed of an array whose transmission axis direction is changed from 90 ° to 135 °, and the fourth stage is an array whose transmission axis direction is changed from 135 ° to 180 °. It is preferable that the structure of the polarizer array from the first stage to the fourth stage is repeated after the first stage. In (1) and (2),
(3) The polarization detector includes an output from the first stage of the polarizer array, an output from the second stage of the polarizer array, an output from the third stage of the polarizer array, and the polarizer. It is preferable to specify the polarization state based on the output from the fourth stage of the array.

[Embodiment 2]
Another embodiment according to the present invention will be described below with reference to FIGS. In addition, in this embodiment, in order to explain a difference from the first embodiment, for the sake of convenience of explanation, members having the same functions as those described in the first embodiment are denoted by the same member numbers. The description is omitted.

  In the present embodiment, the detection optical means 1 shown in FIG. 1 of the first embodiment is different as described below.

  FIG. 8 is a diagram showing a specific configuration of the detection optical means 1 ′ provided in the polarization detection apparatus of the present embodiment.

  As shown in FIG. 8, the detection optical means 1 ′ employed in the present embodiment includes a TDI image sensor 5, and a polarizing plate 60 and a phaser array 70 disposed on the front surface thereof. As shown in FIG. 8, the phaser array 70 is disposed on the light incident side, and the polarizing plate 60 is disposed behind the phaser array 70. That is, the polarizing plate 60 is disposed between the phaser array 70 and the TDI image sensor 5. The output of the TDI image sensor is sent to the calculation processing means 2 as in the first embodiment. In FIG. 8, the TDI image sensor 5, the polarizing plate 60, and the phaser array 70 are installed apart from each other, but may be installed in close contact with each other. The polarization detector can be made compact by installing it closely. Note that the TDI image sensor 5 is the same as that of the first embodiment, and thus description thereof is omitted.

  Since the detection optical means 1 and the sample 4 need only move relative to each other in the present embodiment as in the first embodiment, the detection optical means 1 ′ may be scanned using the scanning stage 3 (FIG. 1). The detection optical means 1 ′ may be fixed and the sample 4 (FIG. 1) may be mounted on the scanning stage 3 for scanning, and the detection optical means 1 and the sample 4 are moved using scanning means (not shown). May be. Moreover, it is not limited to continuous movement, and may be step movement.

  Next, the phase shifter array 70 will be described. FIG. 9 shows a configuration of a phase shifter (phase shifter array region). Reference numeral 80 in FIG. 9 denotes a phaser. Now, it is assumed that light having components oscillating in the X-axis direction and the Z-axis direction and having the same phase is incident on the phase shifter 80. Assume that the phase difference between the components of the transmitted light that vibrate in the X-axis direction and the Z-axis direction becomes φ. An element that varies the speed of light depending on the vibration direction and gives a phase difference is called a phase shifter. If the phase of the component that vibrates in the X-axis direction is ahead of the phase of the component that vibrates in the Z-axis direction as in the phase shifter 80, the X-axis direction is referred to as the fast axis direction of the phase shifter 80. To do.

  Thus, the phaser array 70 is an array of optical elements such as the phaser 80 arranged in an array.

  The phaser array 70 is manufactured so that the fast axis direction shown in FIG. 9 is different in each array. The fast axis of each phaser will be described next.

  FIG. 10 is a schematic view showing each fast axis direction of the phase shifter array 70. The direction of the arrow written in each phaser of the phaser array 70 indicates the direction of the fast axis. The fast axis continuously changes in the X-axis direction of the element, that is, the direction in which the TDI image sensor 5 integrates the detected luminance. Step b1 (first step) in FIG. 10 sets the Z axis (reference axis) to 0 ° from 0 ° to 45 °, and step b2 (second step) sets the Z axis (reference axis) to 0 °. From 45 ° to 90 °, the step b3 (third step) takes the Z axis (reference axis) as 0 °, and the step b4 (fourth step) takes the Z axis (reference axis). ) Is 0 °, and phase shifters 80 having different fast axis angles are arranged in an angle range of 135 ° to 180 °. Below the step b4, the direction of the fast axis is not shown, but the step b1, the step b2, the step b3, and the step b4 are set as a set, and a plurality of sets are arranged.

  Regarding the optical positional relationship between the phaser array 70 and the TDI image sensor 5, each array of the phaser array 70 corresponds to each light receiving element of the TDI image sensor 5. That is, it arrange | positions so that the light which permeate | transmitted each array of the phaser array 70 may each be detected with one light receiving element. Further, the stages b1 and b2 are arranged so as to coincide with the integrated direction of the detected luminance of the TDI image sensor 5. In FIG. 10, it is preferable that the number of array of phase shifter arrays 70 is equal to the number of sensor elements of TDI image sensor 5. For this reason, in FIG. 10, the number of divisions of each stage of the phaser array 70 is indicated by 12, but this is not restrictive. Also, the number of divisions in the Z-axis direction is not limited to the number of divisions as shown in FIG. 10 and is preferably the same as the number of light receiving elements of the TDI image sensor 5.

  The polarization state of the sample 4 (FIG. 1) can be detected by using the polarization detection apparatus including the detection optical means 1 'having the above configuration. The measurement method will be described below. First, an example of the measurement method is shown, and then the measurement method of the present embodiment is described.

  FIG. 11 shows a schematic diagram of an optical system showing an example of polarization measurement. Polarization measurement is to obtain the characteristic information of the sample from the change of the Stokes parameter by obtaining the Stokes parameter of the sample transmitted light and transmitting the sample. The Stokes parameters are represented by S0, S1, S2, and S3 expressed by the following equations (13) to (16).

  Ex and Ez are electric field amplitudes of light in the X-axis direction and the Z-axis direction in FIG. Δ represents the phase difference between Ex and Ez.

  Therefore, the Stokes parameter of the sample transmitted light is measured. FIG. 11 illustrates the transmitted light model. As an optical system, the light source 10, the polarizing plate 11, the quarter wavelength plate 12, the sample 13, the phase shifter 14, the polarizing plate 15, and the detector 16 are arranged in this order. The quarter-wave plate 12 is an element that gives a quarter of the wavelength, that is, π / 2 as the phase difference φ in FIG. The light source 10 may be white light or monochromatic light. However, since the monochromatic light is analyzed by one wavelength, the calculation can be easily performed. The light from the light source 10 passes through the polarizing plate 11 and the quarter-wave plate, becomes circularly polarized light, and enters the sample 13. The light incident on the sample 13 is circularly polarized in FIG. 11, but may be linearly polarized. In the case of entering linearly polarized light, the quarter wave plate 12 is not necessary. The light transmitted through the sample passes through the phase shifter 14 and the polarizing plate 15, and its intensity is detected by the detector 16. If there is no particular problem with the phase shifter 14, a quarter wave plate may be used. In this case, the phase shifter 14 is a quarter wavelength plate.

  As a measurement method, the intensity is detected while rotating the phase shifter 14. When the rotation angle of the phase shifter 14 is C, the detected intensity I (C) is expressed by the following equation (17).

Can be expressed as

  Since the coefficients α1, α2, α3, and α4 are expressed by Stokes parameters (S0, S1, S2, and S3) of light transmitted from the sample, the coefficients α1, α2, α3, and α4 may be obtained. As a method of obtaining, there are a method of Fourier transforming the detected intensity I (C) and a method of obtaining from the integrated intensity as shown below.

When I1, I2, I3, and I4 are defined by the equation (18), α1, α2, α3, and α4 are expressed by the following equations (19) to (22).

It can be expressed as

  As described above, when the integrated intensities I1, I2, I3, and I4 are obtained from the detected intensities according to (Equation 18), α1, α2, α3, and α4 are obtained, and the Stokes parameters (S0, S1, S2) of the transmitted light are obtained. , S3) to obtain characteristic information of the sample.

  In the method shown in FIG. 11, since the phase shifter 14 needs to be rotated, measurement for a short time cannot be performed. Therefore, the polarization detection apparatus of this embodiment is used.

  In the present embodiment, elements corresponding to the phaser 14 in FIG. 11 are in the phaser array 70 in FIG. 10, the polarizing plate 15 in FIG. 11 is in the polarizing plate 60 in FIG. 10, and the detector 16 in FIG. This corresponds to the TDI image sensor 5. In the method described with reference to FIG. 11, the rotation of the phase shifter 14 corresponds to each fast axis of each phase shifter configured in each stage of the phase shifter array 70 shown in FIG. Therefore, the light transmitted through each phase shifter of the stage b1 in FIG. 4 is equivalent to the light when the phase shifter 14 in FIG. 11 is rotated from 0 ° to 45 °. Therefore, in order to obtain the integral represented by Expression (18), it is only necessary to add all the intensities of the light transmitted through the step b1 in FIG. Here, since the output of the TDI image sensor 5 is the sum of the outputs of the stage b1 that has detected the same location, it becomes the integral value itself. Actually, if the output of the stage b1 is B1 in the TDI image sensor 5, the integrated intensity I1 'corresponding to the equation (18) can be expressed by the following equation (23).

δb is the angle difference in the fast axis direction that changes in each array.

  As described above, assuming that the outputs from the stage b2, the stage b3, and the stage b4 are B2, B3, and B4, the integrated intensities I2 ′, I3 ′, and I4 ′ corresponding to the expression (18) are expressed by the following expression (24): ~ Formula (26)

Can be expressed as

  The coefficients α1, α2, α3, and α4 of the detected intensity I are calculated from the equations (23) to (26) using the equations (19) to (22) from the equations I1 ′, I2 ′, I3 ′, and I4 ′. The Stokes parameters (S0, S1, S2, S3) of the sample transmitted light can be obtained.

  In this embodiment, since there is no drive unit for rotating and inserting the optical element, measurement in a short time is possible. Further, since the output from the TDI image sensor 5 is the addition of intensity, the burden on the calculation processing means 2 in FIG. 1 is reduced and the calculation time is shortened. Further, since the TDI image sensor is a scanning sensor, a wide range of measurements can be performed by scanning while imaging.

  The phaser array that can be used in the present embodiment is not limited to the one shown in FIG. For example, it may be as shown in FIG. That is, in the phaser array 70 shown in FIG. 10, the angle of each transmission axis of the phaser constituting the stage b1 continuously changes from one end of the stage b1 to the other end. On the other hand, in the phaser array 70 ′ shown in FIG. 12, the angle of the fast axis of each of the phasers constituting the stage b1 ′ is continuous from one end to the other end of the stage b1 ′. Has not changed. That is, the phaser array that can be employed in the present embodiment is configured by phasers in which one stage has different fast axis angles within an angle range from 0 ° to 45 °. That's fine. Further, the arrangement in the column direction (direction perpendicular to the integration direction) is b1, b2, b3, and b4 in FIG. 10, but is not limited thereto. As shown in FIG. 12, the order may be changed as b1 ', b2', b4 ', b3'.

  Further, as shown in FIG. 13, it is not necessary to assign a phaser array 70 having a different fast axis direction to each light receiving element of the TDI image sensor 5. In FIG. 13, a phaser array having the same fast axis direction is assigned to the two light receiving elements in the integration direction. However, it is better to divide and detect the fast axis direction as finely as possible since the measurement accuracy is improved by assigning it more finely.

  As the phaser array 70, a structural birefringence element can be used. The structural birefringent element is an element 20 in which fine structures having a wavelength equal to or smaller than the wavelength of light are periodically arranged as shown in FIG. When light propagating in the Y direction is incident on the element 20, a phase difference is generated between light components that vibrate in the X direction and the Z direction. A desired phase difference can be obtained by considering the depth of the fine groove and the refractive index of the material. Since the direction of the fast axis can be defined by the direction of the groove, it can be said that it is optimal for manufacturing the phaser array 7 used in this embodiment. Specific examples of the structural birefringent element include those disclosed in non-patent literature (Optical Technology Contact, pp692, Vol. 43, No. 12 (2005)).

  In addition, the structural birefringent element can operate as a phase shifter because the refractive index difference between the X-axis direction and the Z-axis direction is substantially equal for wavelengths longer than about 1.5 times the period f of the microstructure (FIG. 14) Therefore, it can operate in a wide wavelength band. For example, if the period f = 200 nm, the refractive index difference between the X-axis direction and the Z-axis direction is substantially equal to light having a wavelength of 300 nm or more, and functions as a phaser array. Therefore, it is possible to create a phase shifter array that covers all the RGB wavelength bands, and the polarization measurement of the transmitted light from the liquid crystal display can be performed with a single polarization detector. However, since the phase difference φ shown in FIG. 9 varies depending on the wavelength, it is necessary to calculate it in consideration of the polarization measurement.

  In addition, a phaser array made of a photonic crystal may be used instead of the structural birefringence element. When a photonic crystal is used, the operating bandwidth is narrow at 50 nm, but a photonic crystal may be used if it can be limited to detection of a specific wavelength.

  Further, a liquid crystal panel may be used instead of the structural birefringent element. A liquid crystal panel is obtained by sandwiching a liquid crystal layer containing liquid crystal molecules between two substrates. A liquid crystal panel is easy to implement because it can electrically change the fast axis direction. However, since the transmittance is lower than that of other optical elements, the detection accuracy may be deteriorated.

  In this embodiment, as shown in FIG. 10, the phaser array 70 and the polarizing plate 60 are formed by separate elements. However, the present invention is not limited to this, and may be configured as follows. In other words, a polarizer made of a wire grid may be created on the back surface of the phaser array 70 (the surface facing the TDI image sensor 5). The wire grid is a structure in which metal lines formed with a line width of several tens of nm and a pitch of one hundred and several tens of nm are arranged. As the metal, aluminum or the like can be mainly used. Therefore, the polarizing plate 60 may be formed on the back surface of the phaser array 70 with a wire grid. In this element, the direction perpendicular to the line direction is the light transmission axis. A polarizing plate made of a wire grid has a higher transmittance than a normal polarizing plate. In this way, by forming the polarizing plate directly on the back surface of the phaser array 70 with a wire grid, the TDI image sensor is compared with the case where the phaser array 70 and the polarizing plate 60 are configured by separate elements. 5 can be reduced in thickness.

  The wire grid is not limited to the back surface of the phaser array 70. The surface of the phaser array 70, that is, the surface on which the phaser array is formed may be used. In this case, for example, if the phase retarder is a structural birefringent element, a material to be a substrate may be deposited on the fine structure, and a wire grid may be formed thereon.

  As described above, the polarization detection device according to the present embodiment is a light emitted from the phase shifter array 70 including the plurality of phase shifters 80 having the fast axis, the polarizing plate 60, and the sample 4, Detection optical means 1 ′ provided with a TDI image sensor 5 that receives light transmitted through the phaser array 70 and the polarizing plate 60, from the output of the TDI image sensor 5 based on the light received by the TDI image sensor 5, A calculation processing means 2 (FIG. 1) for calculating polarization information of the sample 4 and a scanning stage 3 for causing the detection optical means 1 to move relative to the detection target along the integration direction of the TDI image sensor 5 (FIG. 1). The phaser array 70 aligns four stages of 12 phasers aligned in the integration direction of the TDI image sensor 5 in a direction perpendicular to the integration direction, As described above, each stage is composed of phase shifters having different fast axis angles within a predetermined angle range as described above, and a plurality of the sets are provided along the vertical direction. The TDI image sensor 5 includes a plurality of light receiving elements that receive light transmitted through the phase shifters 80 of the phase shifter array 70. Thereby, it is possible to provide a polarization detecting device capable of measuring the phase difference and the two-dimensional distribution of the optical axis direction of the sample 4 in a wide range, with high accuracy and in a short time.

  In the present embodiment, similarly to the first embodiment, the calculation processing unit 2, the detection optical unit 1, and the scanning stage 3 (detection optical element) may be configured separately.

  Further, in the present embodiment, the configuration in which 0 ° to 180 ° is divided into four parts has been described, but b1 ′, b2 ′, b3 ′, b4 ′, and b5 ′ are detected as shown in FIG. There are also more accurate detection methods. In this case, the phaser array 70 is configured to measure one point in five stages.

  Here, the derivation of the Stokes parameters in the case of dividing into five will be described. In this case, it is derived from the integrated intensity. First, the detection intensity I (C) is the expression (17), and the integrated intensity when the detection intensity is divided into five is the following expression (27).

Can be expressed as C is the rotation angle of the fast axis of the phaser. When I1, I2, I3, I4, and I5 are defined from the equation (27), α1, α2, α3, and α4 are expressed by the following equations (28) to (31).

It can be expressed as

When the integrated intensities I1, I2, I3, I4, and I5 are obtained from the intensities detected as described above by Equation (27), α1, α2, α3, and α4 are obtained, and the Stokes parameters (S0, S1, S2) of the transmitted light are obtained. , S3) to obtain characteristic information of the sample.
The relationship between the outputs B1 ′, B2 ′, B3 ′, B4 ′, B5 ′ from the TDI image sensor 5 and the integrated intensities I1, I2, I3, I4, I5 is expressed by the following equations (32) to (36).

Can be expressed as δb is the angle difference of the fast axis direction that changes in each array.
Stokes parameters (S0, S1, S2, S3) from α1, α2, α3, α4 obtained as described above are expressed by the following equations (37) to (40).

Can be expressed as

  In the phase shifter 80 of the present embodiment, the phase difference φ is generated only in the phase of light oscillating on the X axis and the phase of light oscillating on the Z axis. However, depending on the optical element employed, there is a difference not only in the phase difference but also in the amplitude transmittance. If the amplitude transmittance of the light oscillating in the X axis is r1, and the light oscillating in the Z axis is r2, the equation (17) for detecting intensity change is changed as follows.

In this case, it is necessary to obtain α1, α2, α3, α4, and α5 from the integrated intensities I1, I2, I3, I4, and I5 obtained by the above method, and their relational expressions are the following equations (42) to (42) 46)

It becomes.

  Further, in the case where measurement at one point is sufficient, the phaser array may be only one set of the above-described four or five divisions.

  Further, the direction of the fast axis of the phaser array is different from the intensity integration direction, that is, the TDI integration direction, but is not limited thereto. A plurality of the same direction may exist in the integration direction. If there are a plurality of the same directions, the detection accuracy is deteriorated. However, if the number of overlapping directions and the number of overlaps are small, the detection accuracy is less deteriorated, so there is no problem. For example, there may be a plurality of the same directions due to production problems.

  In addition, in the present embodiment, the fast axis direction is divided and changed in the intensity integration direction and the direction perpendicular thereto, but the direction may change continuously. If the CCD and the fast axis direction are assigned on a one-to-one basis, they will be divided and changed. However, this is not particularly necessary, and it is preferable that they continuously change in the intensity integration direction.

  Moreover, the polarization detection apparatus of this embodiment detected the polarization state of the sample transmitted light. However, the present invention is not limited to this, and the same detection can be performed by detecting the polarization state of the sample reflected light. However, it should be noted that the relational expression between the coefficients α1 to α5 of the detection intensity I (C) and the physical property information of the sample is different. Also, when detecting the transmitted light of the sample, it is necessary to note that the physical property information is an integral value in the thickness direction of the sample. When detecting the reflected light from the sample, depending on the setting of the incident angle to the sample The physical property information on the sample surface is detected.

In other words, it can be said that the polarization detection apparatus according to the present embodiment is characterized by the following points. That is, the polarization detector is
(1) A phase retarder array having a plurality of regions with different fast axis directions and a polarizing plate, and a time delay integration type image sensor that detects light transmitted through the phase retarder array and the polarizing plate. A detection optical means; a calculation processing means for calculating polarization information from an output from the time delay integration type image sensor; and a scanning stage for scanning the detection optical means, and the light transmitted through each array of the phase shifter array is the time delay. Each of the light receiving elements of the integrating image sensor receives light independently, and the phaser array is composed of an array including a region in which the fast axis direction continuously changes in the stage of the integration direction of the time delay integrating image sensor. In other words, the fast axis direction periodically changes in a direction perpendicular to the integration direction of the time delay integration type image sensor. In (1),
(2) The phase shifter array has an array in which the direction of the fast axis changes from 0 ° to 45 ° in the first stage, and the direction of the fast axis changes from 45 ° to 90 ° in the second stage. The third stage is composed of an array in which the direction of the fast axis changes from 90 ° to 135 °, and the fourth stage is composed of an array in which the direction of the fast axis changes from 135 ° to 180 °. In the fifth and subsequent stages, it is preferable that the configuration of the phaser array from the first stage to the fourth stage is repeated. In (1) and (2),
(3) The polarization imaging apparatus includes an output from the first stage of the phaser array, an output from the second stage of the phaser array, an output from the third stage of the phaser array, and the phaser. It is preferable to specify the polarization state based on the output from the fourth stage of the array. Further, in (1) to (3),
(4) The phaser array preferably has a periodic uneven shape. In addition, in (1) to (4),
(5) It is preferable to have the polarizing plate by a wire grid on the back surface of the said phaser array.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and technical means disclosed in different embodiments can be appropriately combined. The obtained embodiments are also included in the technical scope of the present invention.

  The polarized light detection apparatus of the present invention can measure the phase difference of the detection target and the two-dimensional distribution of the optical axis direction in a wide range, with high accuracy and in a short time.

  Therefore, the present invention can be applied as an inspection apparatus to any structure that needs to inspect the polarization state.

It is the figure which showed the structure of one Embodiment of the polarization detection apparatus which concerns on this invention. It is the figure which showed the structure of the detection optical means which is one structure of the principal part of the polarization | polarized-light detection apparatus shown in FIG. It is a figure explaining a polarizer. It is the figure which showed the detail of the detection optical means shown in FIG. It is a figure explaining the optical system of polarization measurement. It is a figure which shows the other form of a polarizer array. It is a figure which shows the other form of a polarizer array. It is the figure which showed the structure of the detection optical means which is one structure of the principal part among the structures of other embodiment of the polarization detector based on this invention. It is a figure explaining the phaser. It is the figure which showed the detail of the detection optical means shown in FIG. It is a figure explaining the optical system of polarization measurement. It is the figure which showed the other form of the phaser array. It is the figure which showed the other form of the phaser array. It is the figure which showed the structure of the phaser array. It is the figure which showed the other form of the phaser array.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 1 'Detection optical means 2 Calculation processing means 3 Scanning stage 4 Sample 5 Time delay integration type (TDI) image sensor 7, 7' Polarizer array 8 Polarizer 10 Light source 11 Polarizing plate 12 1/4 wavelength plate 13 Sample 14 Phaser, polarizing plate 15 Polarizing plate 16 Detector 20 Element 30 Polarization detecting device 60 Polarizing plate 70, 70 ′ Phaser array 80 Phaser

Claims (26)

A polarization detection device for detecting a polarization state of an object to be detected,
A phaser array composed of a plurality of phase shifters, a polarizing plate, and an image sensor for receiving light emitted from the detected object and transmitted through the phase shifter and the polarizing plate are provided. Detection optical means, and
A calculating means for calculating polarization information of the detected object from the output of the image sensor;
The phaser array includes a plurality of phases having different fast axis angles within a predetermined angle range in one stage formed by arranging R (where R is an integer of 2 or more) phasers. A polarization detecting device having a child. The image sensor is a time delay integration type image sensor,
The polarization detection apparatus further includes a scanning stage for relatively moving the time delay integration type image sensor and the detection target along the integration direction of the time delay integration type image sensor.
The polarization detection apparatus according to claim 1, wherein an alignment direction of the phase elements constituting the stage is along an integration direction of the time delay integration type image sensor. The above-described R × N regions configured by arranging the one stage N (where N is an integer of 4 or more) in a direction perpendicular to the alignment direction of the phase shifters constituting the one stage. When the phaser array is made into one set,
The phaser array has a plurality of the sets in the vertical direction,
The above set of L (L is any integer from 1 to N) stages of the above phaser array is (L−1) × 180 ° / N to L × 180 ° / N with reference to the reference axis. The polarized light detection device according to claim 1, wherein the polarization detection device includes the region having a different fast axis angle within an angle range. The set of the phaser arrays is
A first stage including the phaser having a different fast axis angle within an angle range from 0 ° to 45 ° with respect to the reference axis;
A second stage including the phaser having a different fast axis angle within an angle range of 45 ° to 90 ° with respect to the reference axis;
A third stage including the phaser having a different fast axis angle within an angle range of 90 ° to 135 ° with respect to the reference axis;
4. The fourth stage including the phaser having the different fast axis angles within an angle range of 135 ° to 180 ° with respect to the reference axis. 5. Polarization detection device. The set of the phaser arrays is
A first stage including the phaser having a different fast axis angle within an angle range from 0 ° to 36 ° with respect to the reference axis;
A second stage including the phaser having a different fast axis angle within an angle range of 36 ° to 72 ° with respect to the reference axis;
A third stage including the phaser having a different fast axis angle within an angular range of 72 ° to 108 ° with respect to the reference axis;
A fourth stage including the phaser having a different fast axis angle within an angular range of 108 ° to 144 ° with respect to the reference axis;
4. The fifth stage including the phaser having the different fast axis angles within an angle range of 144 ° to 180 ° with respect to the reference axis. 5. Polarization detection device.   The calculating means outputs the output based on the light received at the first stage, the output based on the light received at the second stage, and the light received at the third stage. 5. The polarization detection device according to claim 4, wherein polarization information of the detection target is calculated based on the output based on and the output based on the light received in the fourth stage. 6. .   The calculating means outputs the output based on the light received at the first stage, the output based on the light received at the second stage, and the light received at the third stage. Based on the output based on the output received based on the light received at the fourth stage, and the output based on the light received at the fifth stage, the polarization information of the detected object The polarization detection device according to claim 5, wherein   The polarization detector according to any one of claims 1 to 7, wherein the phaser array has a periodic uneven structure.   In the above phaser array, a periodic uneven structure is formed on one surface of a substrate, and the function of the polarizing plate is realized by forming a wire grid on the other surface or on the upper surface of one surface. The polarized light detection apparatus according to claim 1, wherein the polarization detection apparatus is provided.   The polarization detector according to any one of claims 1 to 9, wherein the phaser array is a liquid crystal panel.   11. The polarization detecting device according to claim 1, wherein the phase shifter array includes a plurality of phase shifters having different fast axis angles within a predetermined angle range.   12. The polarization detecting device according to claim 1, wherein all of the phase shifters constituting the one stage have different fast axis angles. A polarization detection device for detecting a polarization state of an object to be detected,
A detection optical means provided with a polarizer array composed of a plurality of polarizers, and an image sensor that receives the light emitted from the detection object and transmitted through the polarizer; and
A calculating means for calculating polarization information of the detected object from the output of the image sensor;
The polarizer array includes a plurality of polarizers having different transmission axis angles within a predetermined angle range in one stage in which R (where R is an integer of 2 or more) polarizers are aligned. A polarization detecting device characterized by comprising: The image sensor is a time delay integration type image sensor,
The polarization detection apparatus further includes a scanning stage for relatively moving the time delay integration type image sensor and the detection target along the integration direction of the time delay integration type image sensor.
14. The polarization detection apparatus according to claim 13, wherein the alignment direction of the polarizers constituting the stage is along the integration direction of the time delay integration type image sensor. The above-mentioned R × N regions configured by arranging the one stage N (where N is an integer of 4 or more) in a direction perpendicular to the alignment direction of the polarizers constituting the one stage. When the polarizer array is made into one set,
The polarizer array has a plurality of the sets in the vertical direction,
The above-mentioned set of the L stage (L is any integer from 1 to N) of the polarizer array is from (L-1) × 180 ° / N to L × 180 ° / N with reference to the reference axis. The polarization detector according to claim 13 or 14, comprising the polarizer having different transmission axis angles within an angular range. The set of polarizer arrays is
A first stage including the polarizer having a different transmission axis angle within an angular range from 0 ° to 45 ° with respect to the reference axis;
A second stage including the polarizer having a different transmission axis angle within an angular range of 45 ° to 90 ° with respect to the reference axis;
A third stage including the polarizer having a different transmission axis angle within an angular range of 90 ° to 135 ° with respect to the reference axis;
16. The fourth stage including the polarizer including the polarizer having different transmission axis angles within an angle range of 135 ° to 180 ° with respect to the reference axis. Polarization detector. The set of polarizer arrays is
A first stage including the polarizer having a different transmission axis angle within an angle range of 0 ° to 36 ° with respect to the reference axis;
A second stage including the polarizer having a different transmission axis angle within an angle range of 36 ° to 72 ° with respect to the reference axis;
A third stage including the polarizer having a different transmission axis angle within an angular range of 72 ° to 108 ° with respect to the reference axis;
A fourth stage including the polarizer having a different transmission axis angle within an angular range of 108 ° to 144 ° with respect to the reference axis;
16. The fifth stage including the polarizer including the polarizer having different transmission axis angles within an angle range of 144 ° to 180 ° with respect to a reference axis. Polarization detector.   The calculating means outputs the output based on the light received at the first stage, the output based on the light received at the second stage, and the light received at the third stage. The polarization detection device according to claim 16, wherein polarization information of the detection target is calculated based on the output based on the output based on the light received at the fourth stage. .   The calculating means outputs the output based on the light received at the first stage, the output based on the light received at the second stage, and the light received at the third stage. Based on the output based on the output received based on the light received at the fourth stage, and the output based on the light received at the fifth stage, the polarization information of the detected object The polarization detection device according to claim 17, wherein   The polarization detector according to any one of claims 14 to 19, wherein the polarizer array realizes a polarization function by forming a wire grid on one surface of a substrate.   21. The polarization detecting apparatus according to claim 13, wherein the polarizer array includes a plurality of polarizers having transmission axis angles different from each other within a predetermined angle range.   The polarization detector according to any one of claims 13 to 21, wherein all of the polarizers constituting the stage have different transmission axis angles. A detection optical element provided in a polarization detection device for detecting a polarization state of a detection object,
The detection optical element includes a plurality of phases having different fast axis angles within a predetermined angle range in one stage in which R (where R is an integer equal to or greater than 2) phase shifters are aligned. A detection optical element comprising a phaser array having a child. A detection optical element provided in a polarization detection device for detecting a polarization state of a detection object,
The detection optical element includes a plurality of polarizers having different fast axis angles within a predetermined angle range in one stage in which R (where R is an integer of 2 or more) polarizers are aligned. A detection optical element characterized by being a polarizer array. A polarization detection method for detecting a polarization state of an object to be detected,
The light emitted from the subject
After passing through a phaser array having a plurality of phasers having different fast axis angles within a predetermined angle range,
Let it pass through the polarizing plate,
The light transmitted through the polarizing plate is received by the image sensor,
A polarization detection method, wherein an output from the image sensor is input to a calculation means for calculating polarization information of the detection object, and a polarization state of the detection object is detected. A polarization detection method for detecting a polarization state of an object to be detected,
The light emitted from the subject
A polarizer array having a plurality of polarizers having different fast axis angles within a predetermined angle range;
The light transmitted through the polarizer array is received by the image sensor,
A polarization detection method, wherein an output from the image sensor is input to a calculation means for calculating polarization information of the detection object, and a polarization state of the detection object is detected.

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