JP5818643B2 - Wavefront sensor and adaptive optics - Google Patents

Description

  The present invention relates to a Shack-Hartmann wavefront sensor and an adaptive optics system using the wavefront sensor.

  The Shack-Hartmann wavefront sensor forms a light wave into a large number of spot images by a lenslet array in which a large number of small lenses (lenslets) are arranged in a lattice pattern, and measures the wavefront distribution from the image pattern. A CCD (Charge Coupled Device) is generally used for detecting an imaging pattern of a spot image.

  A Shack-Hartmann wavefront sensor is generally used in an adaptive optics system. The adaptive optics system is a technique for controlling the wavefront of a light wave so as to cancel the wavefront distortion fluctuation caused by atmospheric fluctuation, vibration, etc. in the spatial propagation of light (for example, see Non-Patent Document 1). In an adaptive optics system, a wavefront sensor that measures wavefront distortion in real time following surface distortion fluctuations is required. The repeated measurement frequency of the wavefront sensor needs to be 10 times faster than the time frequency of wavefront distortion. In an adaptive optics system for a large astronomical telescope, the influence of atmospheric fluctuations increases as the aperture system of the telescope increases, and therefore, a wavefront sensor having a high repeated measurement frequency is required. However, a normal CCD has a limit of operation of about 200 Hz. Even when a CMOS image sensor capable of speeding up as compared with a CCD is used, about 1 kHz is the limit in consideration of performance degradation accompanying speeding up. Conventionally, for example, in the wavefront sensor described in Patent Document 1, high speed is achieved by arranging a large number of four-quadrant photodiodes in an arrangement corresponding to the lenslet instead of an image pickup device such as a CCD.

JP-A-8-261842

Hideki Takami, “Compensation optics in the TMT era”, Journal of Infrared Radiology Society of Japan 19 (1 ・ 2), 45-48,5, 2010-05

Since the conventional wavefront sensor is configured as described above, it is possible to measure the wavefront at high speed. However, there are the following problems.
First, it is not easy to arrange a large number of 4-quadrant photodiodes closely, and requires significantly higher development and manufacturing costs compared to CCD and CMOS image sensors that are widely used in consumer camera applications. And
Second, one spot image must be formed so as to straddle four photodiodes. If the displacement of the spot image becomes larger than a certain level, this condition cannot be satisfied.
Third, when this wavefront sensor is used in an adaptive optical system, there is a problem that it does not function in a state where a tilt deviation due to vibration or initial alignment deviation is large due to the second problem.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to obtain a wavefront sensor and an adaptive optical system capable of increasing the processing speed and reducing the cost.

  The wavefront sensor according to the present invention images a lenslet array that forms a large number of condensing point patterns according to the wavefront shape of an incident light wave, and images a plurality of condensing point patterns that are formed by the lenslet array. In the two-dimensional detector for converting to a signal and the Shack-Hartmann wavefront sensor for detecting the wavefront distortion of the light wave from the output signal of the two-dimensional detector, the scanning direction of at least one of the horizontal scanning and the vertical scanning of the two-dimensional detector , A control circuit that controls scanning so as to read out a plurality of preset partial image areas and does not scan image areas other than the plurality of partial image areas is provided. And the plurality of partial image areas are arranged at substantially equal intervals, and the lenslets constituting the lenslet array are in the scanning direction of the two-dimensional detector. The lenslets are arranged in a substantially parallel grid arrangement, and the lenslet arrangement interval is set equal to the interval of the partial image areas of the two-dimensional detector. It is configured to be detected in the partial image area of the dimension detector.

  The wavefront sensor of the present invention performs scanning so as to read out a plurality of partial image areas having a predetermined width in at least one of the horizontal scanning direction and the vertical scanning direction of the two-dimensional detector, and a plurality of parts Since the image area other than the image area is not scanned, the processing speed can be increased and the cost can be reduced.

It is explanatory drawing of the wavefront sensor by Embodiment 1 of this invention. It is a block diagram of the CMOS image sensor in the wavefront sensor by Embodiment 1 of this invention. It is a block diagram which shows the lenslet array of the wavefront sensor by Embodiment 1 of this invention. It is explanatory drawing which shows the relative arrangement | positioning of the two-dimensional detector of the wavefront sensor and lenslet array by Embodiment 1 of this invention. It is a block diagram which shows the adaptive optics system by Embodiment 2 of this invention. It is explanatory drawing which shows the state of the wavefront sensor when the wavefront distortion of the adaptive optics system by Embodiment 3 of this invention cannot be detected. It is a flowchart which shows the operation | movement sequence of the adaptive optics system by Embodiment 3 of this invention. It is a block diagram which shows the adaptive optics system by Embodiment 4 of this invention. It is explanatory drawing of the switching mirror of the adaptive optics system by Embodiment 4 of this invention.

Embodiment 1 FIG.
FIG. 1 is an explanatory diagram of functions related to the readout circuit of the two-dimensional detector 10 in the wavefront sensor according to Embodiment 1 of the present invention.
As illustrated, the two-dimensional detector 10 includes a light receiving unit 11 in which photodiodes that perform photoelectric conversion are arranged in a lattice pattern. The output of one photodiode of the light receiving unit 11 is converted into the luminance value of the captured image. The vertical scanning circuit 4 is a circuit that scans and reads an electrical signal accumulated in the photodiode of the light receiving unit 11 in the vertical direction, and the horizontal scanning circuit 5 is a circuit that scans and reads in the horizontal direction. The partial image region 12 is a partial region of the light receiving unit 11, is a partial readout region that is parallel to the horizontal scanning direction and has a predetermined width in the vertical scanning direction, and is arranged at equal intervals. It is. The control circuit 13 is a control circuit that controls the vertical scanning circuit 4 and the horizontal scanning circuit 5 to cooperate to read out an electrical signal from the light receiving unit 11 as an image. That is, the control circuit 13 performs scanning so as to read out the plurality of partial image areas 12 in at least one of the horizontal scanning direction and the vertical scanning direction of the two-dimensional detector 10, and image areas other than the partial image area 12 are scanned. Control not to scan.

  In the first embodiment according to the present invention, a CMOS image sensor is used as the two-dimensional detector 10. The CMOS image sensor has the same configuration as that generally used as an image sensor of a consumer digital video camera (monochrome). FIG. 2 is a block diagram for explaining the operating principle of the CMOS image sensor used as the two-dimensional detector 10 of the wavefront sensor according to the first embodiment of the present invention.

  In FIG. 2, the two-dimensional detector 10 includes a photodiode 1, a cell amplifier 2, a noise canceller 3, a vertical scanning circuit 4, a horizontal scanning circuit 5, and an output amplifier 6. Here, since the vertical scanning circuit 4 and the horizontal scanning circuit 5 are the same as those in FIG. 1, their description is omitted here. Although a large number of photodiodes 1 are arranged in a two-dimensional lattice shape, FIG. 2 shows a simplified arrangement of 4 × 4. The photodiode 1 converts the received light into an electrical signal. The cell amplifier 2 is an amplifier provided for each photodiode 1 and amplifies the electric signal photoelectrically converted by the photodiode 1 with a predetermined gain. The cell amplifier 2 includes a switching element and is connected in parallel between elements adjacent in the vertical direction. A signal line in which the cell amplifiers 2 are connected in parallel in the vertical direction is connected in parallel in the horizontal direction via a noise canceller 3 that is a circuit for removing noise and a switching element, and then amplified and output by the output amplifier 6. Each switching element can be opened and closed by the horizontal scanning circuit 5 or the vertical scanning circuit 4, and is controlled by the control circuit 13 so as to be read in the order of raster scanning.

  As described above, the CMOS image sensor performs scanning readout using the switching element. Normally, the configuration is such that all pixels are read out by raster scanning, but it is possible to read out only specific pixels by changing the design of the control circuit 13. Using this feature, the control circuit 13 is configured so that pixels existing in a plurality of partial image areas 12 (rectangular areas) as shown in FIG. 1 are read and other pixels are skipped. The widths of the plurality of partial image areas 12 are equal to A. Further, the interval between adjacent partial image areas 12 is equal to B. A and B are pixel units.

FIG. 3 is a block diagram showing the lenslet array 20 constituting the wavefront sensor according to Embodiment 1 of the present invention. As shown in FIG. 3, the lenslet array 20 includes a plurality of lenslets 21. The lenslet 21 shown here has a rectangular outer shape, and the lenslet array 20 is configured by arranging a large number of lenslets 21 in a lattice pattern. The interval between the adjacent lenslets 21 is substantially equal to the interval between the partial image regions 12 shown in FIG.
In FIG. 3, 36 lenslets 21 are arranged. However, it is common to arrange about 100 to 2000 lenses, and the number of lenslets 21 shown in the first embodiment is limited to 36. It is not a thing.

FIG. 4 is an explanatory diagram showing a relative arrangement of the two-dimensional detector 10 and the lenslet array 20 of the wavefront sensor according to the first embodiment of the present invention. 4, the same parts as those in FIGS. 1 to 3 are denoted by the same reference numerals, and the description thereof is omitted.
In FIG. 4, a condensed spot image 22 is an image of light collected by the lenslet array 20 and is configured such that the focal point of the lenslet 21 and the photodiode of the light receiving unit 11 coincide. Further, the arrangement of the lenslets 21 in the horizontal direction and the longitudinal direction of the partial image region 12 of the light receiving unit 11 are configured to be parallel. Further, the partial image region 12 is configured to coincide with the optical axis of the lenslet 21. With this configuration, when the wavefront distortion amount and inclination of input light are equal to or less than a predetermined value, the condensed spot image 22 is captured in the partial image region 12.

In the two-dimensional detector 10 of the wavefront sensor according to the first embodiment of the present invention, the electric signal recorded in the pixel is read out in synchronization with the horizontal synchronizing signal repeated at a constant frequency. Accordingly, the time for reading out the electrical signal obtained by photoelectrically converting all the focused spot images 22 is proportional to the number of pixels to be read out. Therefore, in the wavefront sensor according to the first embodiment, the electric power of all spot images can be obtained in a short time as shown in the following equation as compared with the time for reading all the pixels included in the two-dimensional detector 10 (all pixel reading time). The signal can be read out.
Reading time for all spot images = B / A * (reading time for all pixels)

Since the wavefront sensor according to the first embodiment of the present invention is configured as described above, the following effects can be obtained.
First, it is possible to read out electrical signals of all spot images in a shorter time than a conventional wavefront sensor. Therefore, the measurement frequency is higher than that of the conventional wavefront sensor, that is, high-speed measurement is possible.

  In the first embodiment, the partial reading range is limited by limiting the reading range with respect to vertical scanning. As an effect, the modification scale of the control circuit 3 of the conventional CMOS image sensor can be reduced, and therefore cost merit is easily obtained. However, it goes without saying that a wavefront sensor with a higher measurement frequency can be obtained by limiting the partial readout range even in horizontal scanning. The shape of the partial image region 12 of the first embodiment is merely a typical example, and is not limited to this.

  As described above, according to the wavefront sensor of the first embodiment, the lenslet array that forms a large number of condensing point patterns according to the wavefront shape of the incident light wave, and the many lenslet arrays that form an image. Horizontal scanning of a two-dimensional detector in a two-dimensional detector that picks up a focused spot pattern and converts it into an image signal, and a Shack-Hartmann wavefront sensor that detects wavefront distortion of a light wave from the output signal of the two-dimensional detector And a control circuit that controls scanning so as to read a plurality of preset partial image areas in a scanning direction of at least one of vertical scanning and not scanning image areas other than the plurality of partial image areas. The partial image areas have a predetermined width parallel to the scanning direction, and the plurality of partial image areas are arranged at substantially equal intervals, and the lens labels constituting the lenslet array are arranged. Are arranged in a grid array substantially parallel to the scanning direction of the two-dimensional detector, and the arrangement interval of the lenslets is configured to be equal to the interval of the partial image areas of the two-dimensional detector and is imaged by the lenslets. Since a large number of condensing point patterns are configured to be detected in the partial image region of the two-dimensional detector, the processing speed can be increased and the cost can be reduced.

  Further, according to the wavefront sensor of the first embodiment, since the two-dimensional detector uses a CMOS image sensor, the cost of the wavefront sensor can be reduced.

Embodiment 2. FIG.
FIG. 5 is a configuration diagram illustrating an adaptive optical system according to the second embodiment.
The adaptive optical system shown in FIG. 5 includes a telescope 30, a collimating lens 31, a bending mirror 32, relay lenses 33a and 33b, a deformable mirror 34, a beam splitter 35, an imaging camera 36, a wavefront sensor 37, and a deformable mirror drive control device 38. The observation device 39 is provided.

  The compensation optical system according to the second embodiment is intended to correct wavefront distortion due to atmospheric fluctuations in astronomical observation by an astronomical telescope and realize observation with high resolution. The telescope 30 is a reflective telescope, and collects and forms an image of light from a celestial object to be observed. The light from the celestial body once imaged is converted into substantially parallel light by the collimator lens 31, the optical path is bent by the bending mirror 32, and the light passes through the relay lenses 33a and 33b. The relay lenses 33a and 33b are convex lenses and are afocal optical systems that convert substantially parallel light into substantially parallel light. The exit pupils of the telescope 30 and the collimating lens 31 are arranged so as to be re-imaged on the deformable mirror 34 by the relay lenses 33a and 33b. The deformable mirror 34 is a reflecting mirror that can change the shape of the reflecting mirror to an arbitrary shape by a control command from the deformable mirror drive control device 38, and is the same as that generally used in conventional adaptive optics. . The beam splitter 35 is a flat glass plate that is coated with a coating that reflects part of the incident light and transmits part of the light. The beam splitter 35 branches the light reflected by the deformable mirror 34 in two directions. One of the lights branched by the beam splitter 35 goes to the wavefront sensor 37.

  The wavefront sensor 37 has the same configuration as the wavefront sensor described in the first embodiment. The deformable mirror drive control device 38 includes a computer, analyzes the wavefront distortion output from the wavefront sensor 37, and calculates the mirror surface shape of the deformable mirror 34 for correcting this distortion. Further, the deformable mirror drive control device 38 includes a D / A converter that drives and controls the mirror surface shape of the deformable mirror 34, and is variable so that the mirror surface shape calculated based on the output of the wavefront sensor 37 is obtained. The shape of the mirror 34 is immediately controlled. The remaining one branched by the beam splitter 35 goes to the imaging camera 36. The imaging camera 36 is an imaging device that is composed of an imaging lens and a two-dimensional detector, and is similar to that used for conventional astronomical observation. The imaging camera 36 converts an image of the astronomical object into an electrical signal and outputs it to the observation device 39. The observation device 39 is an image signal processing device that stores and analyzes the celestial image output by the imaging camera 36.

  As described above, the deformable mirror 34 acts to correct the wavefront distortion included in the light before reflection, so that the light from the celestial body reflected by the deformable mirror 34 has a wavefront compared to that before reflection. The distortion is reduced, and the resolution of the image captured by the imaging camera 36 is improved.

The compensating optical system according to Embodiment 2 of the present invention is configured as described above, and therefore has the following effects.
First, since the wavefront sensor 37 having a higher measurement frequency than that of the conventional wavefront sensor is used, the control frequency for correcting the wavefront distortion is made higher than that of the adaptive optical system using the conventional two-dimensional detector. It is possible.
Second, since a wavefront sensor that is less expensive than a wavefront sensor that uses a conventional four-quadrant photodiode is used, the cost can be reduced.

  As described above, according to the adaptive optics system of the second embodiment, the telescope, the collimating lens that converts the light collected by the telescope into substantially parallel light, and the exit pupil formed by the telescope and the collimating lens are provided. An afocal optical system that transfers an image, a deformable mirror that is disposed at a position that substantially coincides with the exit pupil transferred by the afocal optical system, and that reflects a light wave from the afocal optical system according to a predetermined control command; The wavefront sensor according to the first embodiment that detects the wavefront distortion of the light wave reflected by the deformable mirror, and the variable mirror that sends a control command to the variable mirror to correct the wavefront distortion based on the calculation result in the wavefront sensor. Since the drive control device is provided, it is possible to realize high speed and low cost of the compensation optical system.

Embodiment 3 FIG.
In the adaptive optical system according to the second embodiment, the wavefront sensor 37 is configured to read out pixels in the partial image region 12 and not to read out other pixels. For this reason, if the light to be measured has a large wavefront inclination, the wavefront distortion may not be detected. FIG. 6 is an explanatory diagram showing a state of the wavefront sensor 37 when the wavefront distortion cannot be detected. In FIG. 6, the same parts as those in FIG. Assuming such a case, in the third embodiment, a function described below is added to the control circuit 13 of the wavefront sensor 37.

FIG. 7 is a flowchart showing an operation sequence of the adaptive optics system in the third embodiment. Hereinafter, the operation sequence of the third embodiment will be described along each step.
[Step ST1]
Reading of the two-dimensional detector 10 of the wavefront sensor 37 is started.
[Step ST2]
Control the direction that the astronomical telescope collimates toward the object you want to observe. The direction in which the celestial body exists may be calculated by an astronomical database and GPS, or a quasi-telescope may be used.
[Step ST3]
In the image detected by the two-dimensional detector 10, it is determined whether or not light from the observation object is detected. Specifically, it is checked whether the condensing point pattern is imaged. When the condensing point pattern has been imaged, the process proceeds to step ST4. If the condensing point pattern has not been captured, the process proceeds to step ST10.

[Step ST4]
In the image detected by the two-dimensional detector 10, a displacement (D1 in FIG. 6) in the vertical direction from the partial image region 12 is calculated for at least one condensing point constituting the condensing point pattern.
[Step ST5]
The control circuit 13 determines whether or not the focused spot image 22 is in the partial image area 12. Specifically, the magnitude of the displacement D1 and the half value A / 2 of the width of the partial image area 12 are compared. If D1 is smaller than A / 2, the process proceeds to step ST6. Otherwise, the process proceeds to step ST12.

[Step ST6]
The position of the focused spot image 22 is detected from the image read from the two-dimensional detector 10, and the wavefront distortion amount is calculated by the deformable mirror drive control device 38.
[Step ST7]
The reflection surface shape of the deformable mirror 34 is calculated and controlled so as to correct the wavefront distortion amount calculated in step ST6.
[Step ST8]
The control circuit 13 determines whether the two-dimensional detector 10 is reading only the partial image region 12 or all pixels. When only the partial image region 12 is read, it is determined that the wavefront control loop is in progress, and the process returns to step ST3 which is the head of the loop. When all the pixels are read out, it is determined that the wavefront control loop is being prepared, and the process proceeds to step ST9.
[Step ST9]
The control circuit 13 switches the setting so that the two-dimensional detector 10 reads only the partial image area 12. With this operation, the wavefront control loop is ready. Return to step ST3 which is the head of the loop.

[Step ST10]
There are two possible reasons why the focused spot image 22 is not captured in the image at step ST3. First, when the two-dimensional detector 10 is set to read out only the partial image region 12, a case where the condensed spot image 22 is captured outside the partial image region 12 can be considered. In this case, the process proceeds to step ST11. Second, when the two-dimensional detector 10 is set to read out all pixels, the light from the observation object is not incident on the telescope 30. In this case, that is, it is determined that the observation is impossible due to an unexpected reason, and the sequence is terminated.

[Step ST11]
The control circuit 13 is set so as to read out all the pixels of the two-dimensional detector 10. Next, the process returns to step ST3 which is the head of the loop.
[Step ST12]
If it is determined in step ST5 that the focused spot image 22 is outside the partial image area 12, it is conceivable that there is an angular error in the control of the telescope 30 in step ST2. Since the magnitude and direction of this angular error are proportional to D1, it can be estimated from the value of D1. Using this information, the attitude of the telescope 30 is controlled so that the angle error is not more than the allowable value, that is, D1≈0.

Since the adaptive optics system in Embodiment 3 is configured as described above, the following effects can be obtained.
First, when only the pixels in the partial image area 12 are read out, the same effects as in the second embodiment are obtained.
Second, when all the pixels are read out, the focused spot image 22 can be detected even when the wavefront inclination is large although the speed is low. Using the information of the focused spot image 22, the wavefront inclination of the measurement light can be removed by an artificial operation or an automatic operation so that the focused spot image 22 enters the partial image region 12, and the high-speed control loop again. It can be recovered.

  As described above, according to the adaptive optics system of the third embodiment, the control circuit of the wavefront sensor detects a large number of condensing point patterns imaged by the lenslet in the partial image region of the two-dimensional detector. If not, control is performed to scan all pixels of the two-dimensional detector, and during this control, if the condensing point pattern is detected in the partial image area, control is performed so as to return to detection of only the partial image area. Therefore, even when the light to be measured has a large wavefront inclination, the wavefront distortion can be reliably detected, and the wavefront distortion can be reliably corrected as an adaptive optical system.

Embodiment 4 FIG.
FIG. 8 is a configuration diagram illustrating an adaptive optical system according to the fourth embodiment.
As shown in FIG. 8, the adaptive optical system of the fourth embodiment includes a telescope 30, a collimating lens 31, relay lenses 33a and 33b, a deformable mirror 34, a beam splitter 35, an imaging camera 36, a wavefront sensor 37, and a deformable mirror. A drive control device 38, an observation device 39, a steering mirror (chip tilt mirror) 40, a switching mirror 41, an angle sensor 42, and a steering mirror drive control device 43 are provided. Here, since the telescope 30 to the observation device 39 are the same as those in the second embodiment shown in FIG. 5, the same reference numerals are assigned to the corresponding parts, and the description thereof is omitted.

  The steering mirror 40 is a chip tilt mirror that is a plane mirror whose angle can be changed at high speed according to a control signal from the outside, and is controlled based on a control command from the steering mirror drive control device 43. The switching mirror 41 is a mirror that switches in a time division manner so that incident light is reflected and transmitted, and details thereof will be described later. The angle sensor 42 is a sensor configured by a condensing lens and a position detector that detects a two-dimensional position of the light collected by the condensing lens, and a value based on the reflected light from the switching mirror 41 is obtained. To detect. The steering mirror drive control device 43 is a control device that controls the angle of the steering mirror 40 in accordance with a signal from the deformable mirror drive control device 38 or the angle sensor 42.

  FIG. 9 is an explanatory diagram for explaining a mechanism for switching between reflection and transmission of incident light in a time division manner in the switching mirror 41. FIG. 9A is a perspective view of the switching mirror 41. The switching mirror 41 is a glass plate on which a reflective coating that reflects almost all light is applied to the surface in the same manner as a normal plane mirror. An elongated rectangular slit 41a is opened near the center of the glass plate. FIG. 9B is a cross-sectional view of the switching mirror 41. In FIG. 9B, light condensed by the relay lens 33a (see FIG. 8) is indicated by a dotted line 41b, and shows a state in which the light passes through the slit 41a and travels toward the relay lens 33b (see FIG. 8). . At this time, the wavefront sensor 37 can measure the wavefront distortion using the partial image region 12 and can correct the wavefront distortion using the deformable mirror 34. On the other hand, when the wavefront inclination increases, the light from the relay lens 33a hits a position different from the slit 41a, that is, the reflective coating surface, and the light is reflected and travels to the angle sensor 42.

  The steering mirror drive control device 43 calculates the wavefront inclination amount based on the angle at which the light can pass through the slit 41a from the position of the light condensed by the condenser lens of the angle sensor 42. Next, the angle of the steering mirror 40 is controlled so that light from the relay lens 33a passes through the slit 41a. At this time, an angle signal is not output from the angle sensor 42, but the steering mirror drive control device 43 uses the signal from the wavefront sensor 37 or the signal from the deformable mirror drive control device 38 instead. Operates to continue control.

The compensation optical system according to Embodiment 4 of the present invention is configured as described above, and therefore has the following effects.
First, when the wavefront inclination is detected by the angle sensor 42, the wavefront distortion correction using the wavefront sensor 37 can be started immediately after correction by the steering mirror 40, so that stable and high-speed wavefront distortion correction and astronomical observation are possible. is there.
Secondly, by using the switching mirror 41, when the light to be measured has a large wavefront inclination, only the angle sensor 42 bends the light, and the wavefront inclination of the light to be measured is suitable for the range that the wavefront sensor 37 can measure. At the same time, the light that has been incident on the angle sensor 42 can be switched to be incident on the wavefront sensor 37. Therefore, it is not necessary to allocate the measurement light to the two sensors at the same time, and the light use efficiency is improved.

  As described above, according to the adaptive optics system of the fourth embodiment, the steering mirror that reflects and bends the light collected by the telescope in an arbitrary direction in accordance with a given control command, and is reflected and bent by the steering mirror. The lens of the afocal optical system that injects the incident light is arranged in the vicinity of the condensing point of the condensed light, has a flat plate-like shape and has a reflective surface that reflects the light on the flat plate surface, and penetrates from the reflective surface to the back surface. A switching mirror provided with a slit-shaped opening, an angle sensor that detects a value based on the light reflected by the switching mirror, and light that is reflected and refracted by the steering mirror based on the detection value of the angle sensor. A steering mirror drive control device for sending a control command so as to be in the direction of passing through the slit of the switching mirror. Since the light transmitted through the slit of the quenching mirrors so as to detect a partial image area of the two-dimensional detector can be stably perform high-speed wavefront distortion correction.

  In the present invention, within the scope of the invention, any combination of the embodiments, or any modification of any component in each embodiment, or omission of any component in each embodiment is possible. .

  DESCRIPTION OF SYMBOLS 1 Photodiode, 2 cell amplifier, 3 noise canceller, 4 vertical scanning circuit, 5 horizontal scanning circuit, 6 output amplifier, 10 two-dimensional detector, 11 light-receiving part, 12 partial image area, 13 control circuit, 20 lenslet array, 21 lens Let, 22 Condensing spot image, 30 Telescope, 31 Collimating lens, 32 Bending mirror, 33a, 33b Relay lens, 34 Deformable mirror, 35 Beam splitter, 36 Imaging camera, 37 Wavefront sensor, 38 Deformable mirror drive control device, 39 observation device, 40 steering mirror, 41 switching mirror, 41a slit, 42 angle sensor, 43 steering mirror drive control device.

Claims (5)

A lenslet array that forms an image of a number of condensing point patterns according to the wavefront shape of the incident light wave;
A two-dimensional detector that images and converts a plurality of condensing point patterns formed by the lenslet array into image signals;
In the wavefront sensor of the Shack-Hartmann method that detects the wavefront distortion of the light wave from the output signal of the two-dimensional detector,
In at least one of the horizontal scanning direction and the vertical scanning direction of the two-dimensional detector, scanning is performed so that a plurality of preset partial image areas are read out, and image areas other than the plurality of partial image areas are not scanned. Equipped with a control circuit to control,
The plurality of partial image areas have a predetermined width parallel to the scanning direction, and the plurality of partial image areas are arranged at substantially equal intervals,
The lenslets constituting the lenslet array are arranged in a lattice arrangement substantially parallel to the scanning direction of the two-dimensional detector, and the arrangement interval of the lenslets is the interval between the partial image regions of the two-dimensional detector. And is composed of
A wavefront sensor configured to detect a plurality of condensing point patterns formed by the lenslet in a partial image region of the two-dimensional detector.   2. The wavefront sensor according to claim 1, wherein the two-dimensional detector is a CMOS image sensor. With a telescope,
A collimating lens that converts the light collected by the telescope into substantially parallel light;
An afocal optical system that transfers an image of an exit pupil formed by the telescope and the collimating lens;
A deformable mirror that is disposed at a position that substantially coincides with an exit pupil image-transferred by the afocal optical system, and that reflects a light wave from the afocal optical system according to a predetermined control command;
The wavefront sensor according to claim 1 or 2, wherein wavefront distortion of a light wave reflected by the deformable mirror is detected;
An adaptive optics system comprising: a deformable mirror drive control device that sends the control command to the deformable mirror so as to correct wavefront distortion based on a calculation result in the wavefront sensor. A steering mirror that reflects and bends the light collected by the telescope in an arbitrary direction in accordance with a given control command;
The lens of the afocal optical system that enters the light reflected and bent by the steering mirror is disposed in the vicinity of the condensing point of the light to be collected, has a flat plate shape, and has a reflecting surface that reflects the light on the flat plate surface A switching mirror provided with a slit-like opening penetrating from the reflecting surface to the back surface;
An angle sensor for detecting a value based on the light reflected by the switching mirror;
A steering mirror drive control device that sends a control command to the steering mirror so that the light to be reflected / refracted is transmitted through the slit of the switching mirror based on the detection value of the angle sensor;
4. The adaptive optics system according to claim 3, wherein the wavefront sensor detects light transmitted through the slit of the switching mirror in a partial image region of the two-dimensional detector.   The control circuit of the wavefront sensor controls to scan all the pixels of the two-dimensional detector when a large number of condensing point patterns formed by the lenslet are not detected in the partial image region of the two-dimensional detector, 4. The adaptive optics system according to claim 3, wherein during the control, when the condensing point pattern is detected in the partial image area, control is performed so as to return to detection of only the partial image area.

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