Image acquisition device and image acquisition method

Abstract

This image acquisition device comprises: a stage on which a sample is placed; a light output unit that outputs irradiation light; a light guide optical system including an objective lens and a light deflection unit that deflects light from the sample; an imaging element that captures an image of the light from the sample; and a drive unit that moves the visual field position of the objective lens with respect to the sample. During the image acquisition period, irradiation light is output from the light output unit while the visual field position of the objective lens with respect to the sample is moved by the drive unit, and an image of light from the sample is captured by the imaging element. The control unit controls the light deflection unit such that light from the same region in the sample is incident on the same region on the imaging surface of the imaging element in a predetermined period during the image acquisition period.

Description

Image acquisition device and image acquisition method

[0001] One aspect of the present disclosure relates to an image acquisition device and an image acquisition method.

[0002] For example, Patent Document 1 describes an image acquisition device that includes a stage on which a sample is placed, a light emitting means that irradiates instantaneous light, a light guiding optical system including an objective lens arranged to face the sample on the stage, an image sensor that captures an optical image of the sample guided by the light guiding optical system, and a drive unit that moves the field of view position of the objective lens relative to the sample at a predetermined speed. In the image acquisition device described in Patent Document 1, while the field of view position of the objective lens relative to the sample is moved at a predetermined speed by the drive unit, instantaneous light is irradiated from the light emitting means, and optical images of the sample are sequentially captured by the image sensor at a predetermined frame rate.

[0003] JP 2015-87719 A

[0004] In the image acquisition device described above, the irradiation time of the instantaneous light in one frame may be set shorter than the time it takes for the field of view of the objective lens relative to the sample to move by an amount corresponding to one pixel of the image sensor. This is because if the irradiation time of the instantaneous light is set longer than this time, light from the sample may be incident on multiple pixels, causing blurring of the image. On the other hand, if the irradiation time of the instantaneous light is shorter than this time, the intensity of the captured light may be insufficient, and a sufficiently clear image may not be obtained.

[0005] An object of one aspect of the present disclosure is to provide an image acquisition device and an image acquisition method that are capable of acquiring a clear image while suppressing blurring in the image.

[0006] An image acquisition device according to one aspect of the present disclosure is [1] "an image acquisition device comprising: a stage on which a sample is placed; a light output unit that outputs illumination light to be irradiated onto the sample; a light guiding optical system having an objective lens through which light from the sample passes as the illumination light irradiates the sample; and a light deflection unit that deflects the light from the sample that has passed through the objective lens; an image acquisition element that images the light from the sample that has been guided by the light guiding optical system; a drive unit that moves the field of view of the objective lens relative to the sample; and a control unit that controls the light deflection unit, wherein during an image acquisition period, the drive unit moves the field of view of the objective lens relative to the sample while the illumination light is output from the light output unit and the light from the sample is imaged by the image acquisition element, and the control unit controls the light deflection unit so that light from the same region of the sample is incident on the same region on the imaging surface of the image acquisition element during a predetermined period during the image acquisition period."

[0007] This image acquisition device includes a light deflection unit that deflects light from the sample that passes through the objective lens. The light deflection unit is controlled so that light from the same region of the sample is incident on the same region of the imaging surface of the image sensor during a predetermined period of time during image acquisition. This prevents light from the sample from being incident on multiple pixels, even if the time during which the light output unit outputs illumination light during the predetermined period is set longer than the time it takes for the objective lens's field of view relative to the sample to move by an amount corresponding to one pixel of the image sensor (a reference time). Therefore, for example, the time during which the light output unit outputs illumination light during the predetermined period can be set longer than the reference time, thereby ensuring sufficient intensity of the captured light. This image acquisition device therefore enables clear images to be acquired while suppressing image blur.

[0008] An image acquisition device according to one aspect of the present disclosure may be [2] "the image acquisition device according to [1], wherein the image sensor has a plurality of pixels, and the light output unit outputs the irradiation light for a time longer than the reference time, where the time it takes for the field of view position to move by an amount corresponding to one of the pixels is defined as a reference time." In this case, the intensity of the light to be captured can be sufficiently ensured.

[0009] The image acquisition device according to one aspect of the present disclosure may be [3] "the image acquisition device according to [2], wherein the light output unit outputs the irradiation light for a time period that is at least twice the reference time during the predetermined period." In this case, the intensity of the light to be captured can be more sufficiently ensured.

[0010] An image acquisition device according to one aspect of the present disclosure may be [4] "the image acquisition device according to any one of [1] to [3], wherein the light deflection unit includes an optical element having a reflective surface formed thereon, and deflects light from the sample that has passed through the objective lens by reflecting it on the reflective surface, and the control unit rotates the optical element during the predetermined period so that light from the same region of the sample is incident on the same region of the imaging surface of the imaging element." In this case, the light deflection unit can be configured by an optical element having a reflective surface formed thereon.

[0011] An image acquisition device according to one aspect of the present disclosure may be [5] "the image acquisition device according to [4], wherein the light guiding optical system further includes an imaging lens that focuses light from the sample that has passed through the objective lens on the imaging surface of the imaging element, and the optical element is disposed between the imaging lens and the imaging element on the path of light from the sample." In this case, by adjusting the distance between the optical element and the imaging element on the path of light from the sample, it is possible to adjust the sensitivity of a change in the imaging position of the optical image relative to a change in the rotation angle of the optical element.

[0012] An image acquisition device according to one aspect of the present disclosure may be [6] "the image acquisition device according to [4], wherein the light guiding optical system further includes an imaging lens that focuses light from the sample that has passed through the objective lens onto the imaging surface of the image sensor, and the optical element is disposed between the objective lens and the imaging lens on the path of light from the sample." In this case, for example, compared to a case where an optical element is disposed between the imaging lens and the image sensor on the path of light from the sample, it is possible to suppress the occurrence of field curvature in the optical image formed on the imaging surface of the image sensor, and a clear image can be acquired.

[0013] An image acquisition device according to one aspect of the present disclosure may be [7] "the image acquisition device according to any one of [4] to [6], wherein the control unit continues to rotate the optical element in the same rotation direction while the field of view position of the objective lens moves in a predetermined direction during the image acquisition period." In this case, compared to, for example, a case in which the optical element is oscillated (the rotation direction is changed) while the field of view position of the objective lens moves in a predetermined direction during the image acquisition period, the angular velocity of the optical element does not need to be reduced, and therefore the angular velocity of the optical element can be increased.

[0014] An image acquisition device according to one aspect of the present disclosure may be [8] "the image acquisition device according to any one of [4] to [7], further comprising a detection unit that detects the position of the reflecting surface that reflects light from the sample, and the timing of imaging by the imaging element is controlled based on the detection result of the detection unit." In this case, even if the rotation speed of the optical element is unstable, for example, the timing of imaging can be reliably controlled based on the detection result of the detection unit.

[0015] The image acquisition device according to one aspect of the present disclosure may be [9] "the image acquisition device according to any one of [1] to [3], wherein the light deflection unit includes an optical element that refracts light, and deflects light from the sample that has passed through the objective lens by refracting the light, and the control unit rotates the optical element during a predetermined period during the image acquisition period so that light from the same region on the sample is incident on the same region on the imaging surface of the image sensor." In this case, the light deflection unit can be configured using an optical element that refracts light.

[0016] An image acquisition device according to one aspect of the present disclosure may be

[10] "the image acquisition device according to [9], wherein the light guiding optical system further includes an imaging lens that focuses light from the sample that has passed through the objective lens on the imaging surface of the imaging element, and the optical element is disposed between the imaging lens and the imaging element on the path of the light from the sample." In this case, by adjusting the material or thickness of the optical element, it is possible to adjust the sensitivity of the amount of change in the position of the light image formed on the imaging surface of the imaging element relative to the amount of change in the rotation angle of the optical element. Furthermore, since this sensitivity is relatively low compared to when the light deflection unit is configured using an optical element with a reflective surface, for example, it is possible to easily control the rotation angle.

[0017] An image acquisition device according to one aspect of the present disclosure may be

[11] "the image acquisition device according to [9], wherein the light guiding optical system further includes an imaging lens that focuses light from the sample that has passed through the objective lens onto the imaging surface of the imaging element, and the optical element is disposed between the objective lens and the imaging lens on the path of the light from the sample." In this case, the sensitivity of the change in the imaging position of the optical image relative to a change in the rotation angle of the optical element can be adjusted by adjusting the material or thickness of the optical element. Furthermore, since the sensitivity is relatively low compared to when the light deflection unit is configured using an optical element with a reflective surface, for example, the rotation angle can be easily controlled.

[0018] An image acquisition device according to one aspect of the present disclosure may be

[12] "the image acquisition device described in any one of [1] to

[11] , wherein the light guiding optical system further includes an imaging lens that focuses light from the sample that has passed through the objective lens on the imaging surface of the image sensor, and at least one of the objective lens and the imaging lens is movable along a direction intersecting a traveling direction of the light from the sample so that the light from the sample that has passed through the objective lens passes through a center of the imaging lens, and the image sensor is movable in a direction along the imaging surface in accordance with the movement of at least one of the objective lens and the imaging lens so that light from the same region of the sample is incident on the same region on the imaging surface of the image sensor." In this case, for example, even when the light output from the light guiding optical system is shifted along a direction intersecting the optical axis of the imaging lens, the light from the optical deflection unit passes through the center of the imaging lens, thereby improving imaging performance.

[0019] An image acquisition device according to one aspect of the present disclosure may be

[13] "the image acquisition device according to any one of [1] to

[11] , further comprising: a plurality of filters arranged on the imaging surface of the image sensor so as to be aligned along a direction corresponding to a movement direction of the field of view position of the objective lens relative to the sample, the plurality of filters having different filter characteristics; and during the predetermined period during the image acquisition period, light from the sample is captured in each of the regions on the imaging surface of the image sensor corresponding to the plurality of filters." In this case, light transmitted through the plurality of filters having different filter characteristics can be captured by the image sensor. For example, if the plurality of filters transmit light in different wavelength bands, images with higher resolution and color reproducibility can be acquired. Alternatively, for example, if the plurality of filters have different thicknesses, the optical path lengths of the transmitted light can be made different, thereby changing the observation depth in the sample.

[0020] an image acquisition method according to one aspect of the present disclosure, which is

[14] "an image acquisition method using an image acquisition device, the image acquisition device comprising: a stage on which a sample is placed; a light output unit that outputs illumination light to be irradiated onto the sample; a light guiding optical system having an objective lens through which light from the sample passes as the illumination light irradiates the sample; and a light deflection unit that deflects the light from the sample that has passed through the objective lens; an image acquisition element that images the light from the sample that has been guided by the light guiding optical system; a drive unit that moves a field of view position of the objective lens relative to the sample; and a control unit that controls the light deflection unit; the image acquisition method includes an image acquisition step in which the illumination light is output from the light output unit and the light from the sample is imaged by the image acquisition element while moving the field of view position of the objective lens relative to the sample by the drive unit, and during a predetermined period of the image acquisition step, the control unit controls the light deflection unit so that light from the same region of the sample is incident on the same region on an imaging surface of the image acquisition element." According to this image acquisition method, for the reasons described above, it is possible to acquire a clear image while suppressing blurring in the image.

[0021] According to one aspect of the present disclosure, it is possible to provide an image acquisition device and an image acquisition method that are capable of acquiring a clear image while suppressing blurring in the image.

[0022] 1 is a schematic diagram showing an image acquisition device according to an embodiment; (a), (b), and (c) are diagrams for explaining the operation of the light deflection unit; (a) is a graph showing an example of the relationship between the output timing of irradiation light and the rotation angle of the light deflection unit; (b) is a graph showing another example of the relationship between the output timing of irradiation light and the rotation angle of the light deflection unit; (a) is a diagram for explaining an overview of a light guiding optical system; (b) is a diagram showing a first example of a light guiding optical system; (c) is a diagram showing a second example of a light guiding optical system; (c) is a graph showing the irradiation time of irradiation light in an image acquisition device according to a comparative example; (a), (b), and (c) are diagrams for explaining image acquisition in an image acquisition device according to a comparative example; (a), (b), and (c) are schematic diagrams showing an image acquisition device to which a third example of a light guiding optical system is applied; (a), (b), and (c) are diagrams for explaining an example of the operation of the light deflection unit according to the third example; (b) is a diagram showing a fourth example of a light guiding optical system; (c) is a diagram showing a fifth example of a light guiding optical system; (c) is a graph showing the relationship between the rotation angle of the light deflection unit according to the fourth example and the shift amount of the optical image of the sample on the imaging plane of the imaging element. 15A, 15B, and 15C are diagrams for explaining the operation of the light deflection unit according to the fifth example. A graph showing the relationship between the rotation angle of the light deflection unit according to the fifth example and the shift amount of the light image of the sample on the imaging surface of the imaging element. A graph showing an enlarged first quadrant of the graph shown in FIG. 15A. A schematic diagram showing an example of movement of the field of view position of the objective lens. A schematic diagram showing another example of movement of the field of view position of the objective lens. A schematic diagram showing an example of a prism unit. A schematic diagram showing the relationship between the rotation angle of the light deflection unit according to the fifth example and the shift amount of the light image of the sample on the imaging surface of the imaging element. A schematic diagram showing an image acquisition device to which the third example of the light guiding optical system is applied. A schematic diagram showing an example of a plurality of filters. A schematic diagram showing another example of a plurality of filters. A schematic diagram showing another example of an image acquisition device to which the third example of the light guiding optical system is applied. A schematic diagram showing a modified example of the fifth example of the light guiding optical system.

[0023] Hereinafter, a first embodiment and a second embodiment of one aspect of the present disclosure will be described in detail with reference to the drawings. In the following description, the same or equivalent elements will be designated by the same reference numerals, and duplicated descriptions will be omitted. [First embodiment] [Configuration of image acquisition device]

[0024] As shown in FIG. 1 , the image acquisition device 1 includes a stage 2, a light output unit 3, a light-guiding optical system 4, an image sensor 5, a drive unit 6, a rotation mechanism 7, and a control unit 8. For example, the image acquisition device 1 is a virtual slide scanner that captures an image of a sample S on a glass slide (not shown) using a strobe scanning method. In the strobe scanning method, the glass slide (sample S) is moved in one direction while being irradiated with instantaneous light (strobe light), and light generated from the sample S in response to the irradiation of the instantaneous light is captured. As an example, in the image acquisition device 1, a stage 2 on which the sample S (glass slide) is placed is moved horizontally by a drive unit 6. Irradiation light L0 is irradiated onto the sample S from the light output unit 3, and light L from the sample S in response to the irradiation is guided to an imaging surface 5 a of the image sensor 5 by the light-guiding optical system 4. The image sensor 5 captures an image of the sample S by capturing the light L from the sample S. Hereinafter, the moving direction of the stage 2 (the scanning direction of the irradiated light L0 on the sample S) is referred to as direction D1, and the direction along the path of the light L from the sample S to the imaging surface 5a is referred to as direction D2.

[0025] The sample S observed by the image acquisition device 1 is, for example, a biological sample such as tissue cells. While the sample S is described as a biological sample such as tissue cells, the present invention is not limited to this. The sample S may also be, for example, a wafer or a semiconductor device. For example, the semiconductor device may be a logic device, a memory device, or an analog device. As an example, the logic device, memory device, and analog device may be an integrated circuit (IC) or a large-scale integrated circuit (LSI) having a PN junction such as a transistor. For example, the semiconductor device may be a mixed-signal device that combines a logic device, a memory device, and an analog device. For example, the semiconductor device may be a power semiconductor device. As an example, the power semiconductor device may be a high-current / high-voltage MOS transistor, a bipolar transistor, an IGBT, or the like.

[0026] The sample S to be observed by the image acquisition device 1 is placed on the surface of the stage 2 while sealed in a slide glass. The light output unit 3 is disposed on the rear side of the stage 2 (the side opposite the objective lens 41). The light output unit 3 has a light source 3a that outputs irradiating light L0 to the sample S. In this example, the light output unit 3 switches the output of the irradiating light L0 on and off by controlling the on / off of the light source 3a. The light source 3a is, for example, a light source that emits instantaneous light (strobe light). For example, a laser diode (LD), a light-emitting diode (LED), a superluminescent diode (SLD), or a flash lamp-type light source such as a xenon flash lamp may be used as the light source 3a.

[0027] The light-guiding optical system 4 guides an optical image of the sample S to the image sensor 5. The light-guiding optical system 4 includes an objective lens 41, an optical deflection unit 42, and an imaging lens 43. The objective lens 41 is a lens through which light L from the sample S passes. The optical deflection unit 42 deflects the light L from the sample S that has passed through the objective lens 41, thereby guiding the light L from the sample S to the imaging surface 5a of the image sensor 5. The imaging lens 43 is, for example, a tube lens, and forms an image of the light L from the sample S deflected by the optical deflection unit 42 on the imaging surface 5a of the image sensor 5. In the example shown in FIG. 1 , the objective lens 41, the optical deflection unit 42, the imaging lens 43, and the imaging surface 5a are arranged in this order on the path of the light L from the sample S to the imaging surface 5a. Light L from the sample S passes through the objective lens 41, and is then reflected by the movable mirror 50A, which is the light deflection unit 42, toward the imaging lens 43, and is imaged on the imaging surface 5a by the imaging lens 43. The light guiding optical system 4 will be described in detail later.

[0028] Light L from the sample S is generated when the sample S is irradiated with illumination light L0. The illumination light L0 is not light such as diffused light, but is beam-like light with a certain directionality. The light L from the sample S is focused on the imaging surface 5a of the image sensor 5 to form an optical image of the sample S. The optical image of the sample S is an image of transmitted light in the case of bright-field illumination, scattered light in the case of dark-field illumination, or luminescence (fluorescence) in the case of luminescence measurement. It may also be an image of reflected light from the sample S. In these cases, an optical system capable of acquiring a transmitted light image of the sample S, a scattered light image of the sample S, and a luminescence (fluorescence) image of the sample S can be adopted as the light-guiding optical system 4.

[0029] The imaging element 5 captures an image of the light L from the sample S guided by the light-guiding optical system 4. The imaging element 5 has a plurality of pixels on the imaging surface 5a. In the first embodiment, the imaging element 5 is a two-dimensional imaging element (area sensor) having a plurality of pixel rows on the imaging surface 5a. The imaging element 5 may be, for example, a CCD image sensor or a CMOS image sensor. The imaging element 5 sequentially captures optical images of the sample S guided by the light-guiding optical system 4 at a predetermined frame rate.

[0030] As shown in Fig. 2, a plurality of pixel columns Q are arranged along a direction D3 (arrangement direction) on the imaging surface 5a of the imaging element 5. Each pixel column Q is made up of a plurality of pixels arranged along a direction perpendicular to the direction D3 (the left-right direction in the drawing). That is, the imaging surface 5a has a plurality of pixels arranged two-dimensionally (in a matrix). The plurality of pixel columns Q are a first pixel column Q, a second pixel column Q, a third pixel column Q, a fourth pixel column Q, a fifth pixel column Q, a sixth pixel column Q, a sixth pixel column Q, a seventh pixel column Q, a seventh pixel column Q, a eighth ... １ , second pixel column Q ２ , third pixel column Q ３ , ..., M-1th pixel column Q Ｍ－１ and M pixel columns Q Ｍ The direction D3 corresponds to the direction D1 (the direction in which the field of view position of the objective lens 41 moves relative to the sample S). For example, when the stage 2 moves in the direction D1 and the field of view position P of the objective lens 41 moves along the direction D1 (the opposite direction to the direction D1) on the sample S, the optical image of the sample S moves along the direction D3 on the imaging surface 5 a of the image sensor 5.

[0031] Referring again to FIG. 1 , the driving unit 6 moves the field of view position P of the objective lens 41 relative to the sample S. Specifically, the driving unit 6 moves the sample S fixed to the surface of the stage 2 in a direction D1 perpendicular to the direction D2 (the optical axis direction of the objective lens 41), thereby moving the field of view position P along the direction D1 (in the opposite direction to the direction D1). For example, the driving unit 6 is configured by a stepping motor (pulse motor), a piezoelectric actuator, or the like.

[0032] The rotation mechanism 7 rotates the light deflection unit 42 around a central axis C that is perpendicular to the direction D2. In the example shown in Fig. 1, the light deflection unit 42 is a movable mirror 50A. The rotation mechanism 7 includes, for example, a motor as a drive source.

[0033] The control unit 8 physically includes memories such as RAM and ROM, a processor (arithmetic circuit) such as a CPU, a communication interface, a storage unit such as a hard disk, and a display unit such as a display. Examples of the control unit 8 include a personal computer, a microcomputer, and a smart device (smartphone, tablet terminal, etc.). For example, the control unit 8 controls the light deflection unit 42 via the rotation mechanism 7. In the first embodiment, the control unit 8 controls the rotation mechanism 7 to control the rotation angle of the movable mirror 50A. In this example, the control unit 8 also controls and processes other elements in the image acquisition device 1. For example, the control unit 8 may control the on / off of the output of the irradiation light L0 by the light output unit 3, control the image capture by the image sensor 5, and control the movement of the field of view position P of the objective lens 41 relative to the sample S by the drive unit 6. The control unit 8 may also perform image generation processing based on the signal acquired by the image sensor 5. [Operation of the Image Acquisition Device]

[0034] Next, the image acquisition operation by the image acquisition device 1 will be described with reference to FIGS. 2 and 3. FIG. 2 is a diagram for explaining the operation of the light deflection unit 42. For the sake of explanation, FIG. 2 illustrates the imaging surface 5a facing the front side of the page. In FIG. 2, the tilt angle of the movable mirror 50A with respect to the horizontal direction (e.g., direction D1) is defined as a rotation angle θ1. Also, FIG. 2 illustrates only one divided region R out of the multiple divided regions R shown in FIG. 1.

[0035] Fig. 3(a) is a graph showing an example of the relationship between the output timing of irradiated light L0 from the light output unit 3 and the rotation angle θ1 of the movable mirror 50A, and Fig. 3(b) is a graph showing another example of this relationship. In the upper graph of Fig. 3(a), the horizontal axis represents time t, and the vertical axis represents the intensity I of irradiated light L0 from the light output unit 3. In the lower graph of Fig. 3(a), the horizontal axis represents time t, and the vertical axis represents the rotation angle θ1 of the movable mirror 50A. These points are also true in Fig. 3(b).

[0036] First, an overview of the image acquisition operation by the image acquisition device 1 will be described. The image acquisition device 1 acquires an image of the sample S during an image acquisition period T. Here, the image acquisition device 1 images the sample S at a magnification of, for example, 20 times or more and 40 times or less, and therefore the field of view area of ​​the objective lens 41 is smaller than the sample S. Therefore, in order to image the entire sample S, it is necessary to image the sample S while moving the field of view position P of the objective lens 41 relative to the sample S.

[0037] Specifically, in the image acquisition device 1, during an image acquisition period T, the driving unit 6 moves the field of view position P of the objective lens 41 relative to the sample S, while the light output unit 3 outputs the illumination light L0, and the image sensor 5 captures the light L from the sample S. More specifically, first, an image acquisition region is set to include the entire sample S. Next, multiple divided regions (divided regions R shown in FIG. 1 ) are set by dividing the image acquisition region based on the size of the field of view of the objective lens 41. During the image acquisition period T, the field of view position P of the objective lens 41 relative to the sample S is moved so as to pass through all the divided regions, while capturing images of light from each divided region. At this time, light from each region (region A shown in FIG. 2( a)) of the divided region is captured by each of the multiple pixel arrays Q. As a result, partial images corresponding to each divided region are sequentially acquired. Finally, the acquired partial images are combined to generate an overall image of the sample S, thereby capturing an image of the sample S.

[0038] 1 and 2, the field of view position P of the objective lens 41 is moved so as to pass through a plurality of divided regions R arranged along the direction D1, and light from each divided region R is captured. In this example, as shown in FIG. 2, each divided region R includes M regions A arranged along the direction D1, and these M regions A are arranged in a first pixel column Q. １ ~ Mth pixel column Q Ｍ Each image is captured by

[0039] Next, the image acquisition timing of the image acquisition device 1 during the image acquisition period T will be described. In the example shown in Figures 3(a) and 3(b), the image acquisition period T has multiple image acquisition periods T1 (predetermined periods) and multiple non-image acquisition periods T2. The image acquisition periods T1 and non-image acquisition periods T2 are repeated alternately. During each image acquisition period T1, an image is acquired by the image acquisition device 1. During each non-image acquisition period T2, the image acquisition device 1 prepares to acquire the next image.

[0040] For example, when the field of view position P of the objective lens 41 is located in a certain divided region R during a certain imaging period T1, irradiation light L0 is output from the light output unit 3 to that divided region R, and light L from that divided region R is imaged by the image sensor 5. When the field of view position P of the objective lens 41 moves onto another divided region R, the next imaging period T1 begins. During the next imaging period T1, irradiation light L0 is output from the light output unit 3 to another divided region R, and light L from that other divided region R is imaged by the image sensor 5. During a non-imaging period T2, which is the period between the imaging period T1 and the next imaging period T1, preparations are made to start the next imaging period T1.

[0041] Next, the operation of each unit during the imaging period T1 will be described. The control unit 8 controls the light deflection unit 42 in accordance with (synchronization with) the movement of the sample S. Specifically, the control unit 8 controls the rotation angle θ1 of the movable mirror 50A so that the reflective surface 50a of the movable mirror 50A follows the movement of the sample S. In the example shown in FIG. 2 , the control unit 8 changes the rotation angle θ1 of the movable mirror 50A in synchronization with the movement of the sample S, thereby directing the light LA ​​from the region A in the divided region R to one pixel row Q (in this example, the second pixel row Q) on the imaging surface 5a of the image sensor 5 over the imaging period T1. ２ ) on the imaging surface 5a. ２ ) continues to be incident on

[0042] More specifically, as shown in FIG. 2A, light LA ​​from the region A in the divided region R is incident on the second pixel row Q on the imaging surface 5 a of the imaging element 5 during the imaging period T1. ２ 2B, as the sample S moves, the movable mirror 50A rotates so that the reflecting surface 50a follows the sample S. Next, as shown in FIG. 2C, as the sample S moves further, the movable mirror 50A rotates further so that the reflecting surface 50a follows the sample S. In this way, the control unit 8 controls the movable mirror 50A by rotating the movable mirror 50A in synchronization with the movement of the sample S. As a result, the light LA ​​from the region A in the divided region R is reflected by the second pixel row Q over the imaging period T1. ２ The light L continues to be incident on the sample S. As a result, although the sample S is moving, the light L from the sample S can be prevented from moving on the imaging surface 5a. As a result, the time for outputting the irradiated light L0 during the imaging period T1 can be set to, for example, a time equivalent to three pixels (a time three times longer than a reference time equivalent to one pixel, which will be described later), and the intensity of the imaged light L can be tripled compared to when an image is acquired by outputting the irradiated light L0 for a time equivalent to one pixel.

[0043] As described above, the control unit 8 controls the light deflection unit 42 so that the light LA ​​from the same region (region A) of the sample S is incident on the same region (same pixel row Q) on the imaging surface 5a of the image sensor 5 during the imaging period T1 in the image acquisition period T. The light output unit 3 then outputs the illumination light L0 during the imaging period T1 for a time longer than the reference time. For example, the light output unit 3 outputs the illumination light L0 during the imaging period T1 for a time at least twice the reference time. Here, the reference time is the time required for the field of view position P of the objective lens 41 to move along the direction D1 by an amount corresponding to one pixel (one pixel row Q). For example, if the rotation angle θ1 of the movable mirror 50A is constant and the field of view position P of the objective lens 41 moves by the reference time, the optical image of the sample S on the imaging surface 5a of the image sensor 5 moves by a distance equivalent to one pixel (e.g., the width W shown in FIG. 2A) (the width of the pixel row Q in the direction D3).

[0044] 3A and 3B, the timing at which the light output unit 3 outputs the irradiation light L0 during the image acquisition period T and changes in the rotation angle θ1 of the movable mirror 50A will be described. The control unit 8 rotates (oscillates) the movable mirror 50A in one direction and the other direction during the image acquisition period T. Specifically, the control unit 8 causes the light output unit 3 to output the irradiation light L0 during the image acquisition period T1 and rotates the movable mirror 50A in one direction (the direction in which the rotation angle θ1 increases or decreases). During the non-image acquisition period T2, the control unit 8 stops the light output unit 3 from outputting the irradiation light L0 and rotates the movable mirror 50A in the other direction.

[0045] 3A, the rotation speed of the movable mirror 50A in the non-imaging period T2 may be faster than the rotation speed of the movable mirror 50A in the imaging period T1. Alternatively, as shown in FIG. 3B, the rotation speed of the movable mirror 50A may be constant throughout the entire image acquisition period T. [Configuration of the Light-Guiding Optical System]

[0046] The configuration of the light-guiding optical system 4 will be described with reference to Figures 4, 5, and 6. Figure 4 is a diagram for explaining an overview of the light-guiding optical system 4. Figure 4 shows a fourth example (Figure 11) of the light-guiding optical system 4, which will be described later. Figure 5 is a diagram showing a first example of the light-guiding optical system 4. Figure 6 is a diagram showing a second example of the light-guiding optical system 4. The light-guiding optical system 4 shown in Figures 1 and 2 is the same as the second example of the light-guiding optical system 4 shown in Figure 6.

[0047] In the example shown in FIGS. 5 and 6 , the light deflection unit 42 is a reflective optical element 50 (optical element) having a reflective surface 50a. The reflective optical element 50 deflects light L from the sample S that has passed through the objective lens 41 by reflecting it at the reflective surface 50a. The reflective optical element 50 is, for example, the movable mirror 50A shown in FIGS. 1 and 2 , and examples thereof include a reflective galvanometer mirror, a digital mirror device (DMD), a MEMS (microelectromechanical systems) mirror, or a reflective spatial light modulator (SLM). Note that the light deflection unit 42 may be a transmissive optical element instead of a reflective optical element. For example, the light deflection unit 42 may be a transmissive galvanometer mirror.

[0048] 5, the light deflection unit 42 is disposed between the objective lens 41 and the imaging lens 43 on the path of the light L from the sample S. The movable mirror 50A is disposed on the opposite side of the imaging lens 43 from the objective lens 41. The movable mirror 50A is disposed at a position where the light L from the sample S is converted into convergent light by the imaging lens 43 (between the imaging lens 43 and the image sensor 5) (see FIG. 4). The movable mirror 50A reflects the light L that has passed through the imaging lens 43 toward the imaging surface 5a of the image sensor 5 at the reflecting surface 50a.

[0049] 6, the optical deflection unit 42 (movable mirror 50A) is disposed between the imaging lens 43 and the imaging surface 5a on the path of the light L from the sample S. The movable mirror 50A is disposed at a position (between the objective lens 41 and the imaging lens 43) where the light L from the sample S is converted into parallel light by the objective lens 41 (see FIG. 4). The movable mirror 50A reflects the light L that has passed through the objective lens 41 toward the imaging lens 43 at the reflecting surface 50a. The reflected light L passes through the imaging lens 43 and then is incident on the imaging surface 5a of the image sensor 5.

[0050] 5 and 6, the control unit 8 can shift the focusing position P50 of the light L on the imaging surface 5a by changing the rotation angle θ1 of the movable mirror 50A via the rotation mechanism 7 (see FIG. 1). For example, in the example of FIG. 5, when the movable mirror 50A is rotated clockwise, the focusing position P50 of the light L shifts on the imaging surface 5a in a direction approaching the imaging lens 43. In the example of FIG. 6, when the movable mirror 50A is rotated clockwise, the focusing position P50 of the light L shifts on the imaging surface 5a in a direction approaching the objective lens 41. [Image Acquisition Method]

[0051] The image acquisition method according to the embodiment is an image acquisition method using the image acquisition device 1 according to the first embodiment. The image acquisition method includes an image acquisition step in which, while the driving unit 6 moves the field of view position P of the objective lens 41 relative to the sample S, the light output unit 3 outputs irradiation light L0 and the image sensor 5 captures the light L from the sample S. During an image capture period T1 (predetermined period) of the image acquisition step, the control unit 8 controls the light deflection unit 42 so that light from the same region on the sample S is incident on the same region on the image capture surface 5a of the image sensor 5. [Functions and Effects of the First Embodiment]

[0052] The image acquisition device 1 and image acquisition method include a light deflection unit 42 that deflects light L from the sample S that has passed through the objective lens 41. During an image acquisition period T1 (a predetermined period) within the image acquisition period T, the light deflection unit 42 is controlled so that light from the same region of the sample S is incident on the same region of the imaging surface 5a of the image sensor 5. This prevents light L from the sample S from being incident on multiple pixels, even if the time during which the light output unit 3 outputs the illumination light L0 during the image acquisition period T1 is set longer than the time (reference time) required for the field of view position P of the objective lens 41 relative to the sample S to move by an amount corresponding to one pixel of the image sensor 5. Therefore, for example, the time during which the light output unit 3 outputs the illumination light L0 during the image acquisition period T1 can be set longer than the reference time, thereby ensuring sufficient intensity of the imaged light. For example, the time during which the illumination light L0 is output can be set to a time equivalent to N pixels, thereby increasing the intensity of the light L from the sample S by approximately N times. Therefore, the image acquisition device 1 can acquire clear images while suppressing image blur.

[0053] The above points will be further explained with reference to FIGS. 7 and 8. FIG. 7 is a graph showing the irradiation time of the irradiation light from the light output unit of the image acquisition device according to the comparative example. FIGS. 8(a), 8(b), and 8(c) are diagrams for explaining image acquisition by the image acquisition device according to the comparative example. FIGS. 8(a), 8(b), and 8(c) show a sample S moving in one direction, an objective lens 1041 arranged opposite the sample S, and an area sensor 1005 that captures light L from the sample S that has passed through the objective lens 1041. Note that arrows on the sample S indicate portions S1, S2, and S3 of the sample S. Arrows next to the area sensor 1005 indicate light images S20 to S23 of a portion S2 of the sample S formed on the imaging surface 1005a of the area sensor 1005. The hatched sample S in FIG. 8(c) indicates that no irradiation light is output at that timing.

[0054] As shown in FIG. 7 , in the image acquisition device according to the comparative example, the irradiation time T0 of the irradiation light is set to be equal to or shorter than the reference time. In FIG. 7 , the irradiation time T0 of the irradiation light is set to be the same length as the reference time. More specifically, as shown in FIG. 8( a), in the image acquisition device, in order to image the sample S at high speed, the image may be captured while moving the sample S at a constant speed. However, in this case, as shown in FIG. 8( b), the light image S20 formed on the imaging surface 1005a of the area sensor 1005 also moves at a constant speed (light images S21, S22, and S23), which may cause blurring in the image captured by the area sensor 1005, resulting in a blurred image. Therefore, as shown in FIG. 8( c), it is conceivable to suppress image blurring by setting the irradiation time of the irradiation light to the time corresponding to one pixel. However, in this case, the intensity of the captured light may be insufficient, and a sufficiently clear image may not be acquired. In contrast to this, in the image acquisition device 1 of this embodiment, as described above, the time during which the light output unit 3 outputs the irradiation light L0 during the imaging period T1 can be set to be longer than the reference time (the time corresponding to one pixel), making it possible to acquire a clear image while suppressing blurring of the image.

[0055] The light output unit 3 outputs the irradiated light L0 for a time longer than the reference time during the imaging period T1 (predetermined period). In this case, the intensity of the light to be imaged can be ensured sufficiently. Furthermore, the light output unit 3 outputs the irradiated light L0 for a time more than twice the reference time during the imaging period T1 (see FIGS. 3(a), 3(b), and 7). In this case, the intensity of the light to be imaged can be ensured even more sufficiently.

[0056] The movable mirror 50A (light deflection unit 42) deflects the light L from the sample S that has passed through the objective lens 41 by reflecting it on the reflective surface 50a of the movable mirror 50A, and the control unit 8 rotates the movable mirror 50A for a predetermined period of time so that light from the same region of the sample S is incident on the same region of the imaging surface 5a of the imaging element 5. In this case, the light deflection unit 42 can be configured by the movable mirror 50A (optical element) on which the reflective surface 50a is formed.

[0057] The movable mirror 50A (optical element) is disposed between the imaging lens 43 and the image sensor 5 on the path of the light L from the sample S. In this case, by adjusting the distance D between the movable mirror 50A and the image sensor 5 on the path of the light L from the sample S (see FIG. 5 ), it is possible to adjust the sensitivity of the change in the imaging position of the optical image relative to the change in the rotation angle of the movable mirror 50A.

[0058] The movable mirror 50A (optical element) is disposed between the objective lens 41 and the imaging lens 43 on the path of the light L from the sample S. In this case, compared to a case where the movable mirror 50A is disposed between the imaging lens 43 and the image sensor 5 on the path of the light L from the sample S, for example, it is possible to suppress the occurrence of field curvature in the optical image formed on the imaging surface 5a of the image sensor 5, and a clear image can be acquired. [Modification of the First Embodiment]

[0059] FIG. 9 is a diagram illustrating an image acquisition device 1 to which a third example of the light-guiding optical system 4 is applied. FIG. 10 is a diagram illustrating an example of the operation of the light deflection unit 42 according to the third example. In FIG. 9, the hatched sample S indicates a state in which no irradiation light is being output, and the unhatched sample S indicates a state in which irradiation light is being output. While the reflective optical element 50 of the first embodiment is a movable mirror 50A having a single reflective surface 50a, the reflective optical element 50 of the third example is a movable mirror 50B having multiple reflective surfaces 50a. In the third example, the multiple reflective surfaces 50a are arranged to surround the central axis C of the movable mirror 50B, which is perpendicular to direction D2. The multiple reflective surfaces 50a form a polygonal shape when viewed from a direction parallel to the central axis C. Each reflective surface 50a faces the opposite side of the central axis C. In the example illustrated in FIG. 9, the movable mirror 50B is a polygonal mirror.

[0060] The movable mirror 50B rotates to sequentially reflect the light L from the sample S on the multiple reflecting surfaces 50a. The rotation angle θ2 is the tilt angle of the reflecting surfaces 50a that reflect the light L from the sample S with respect to the horizontal direction (e.g., direction D1). Specifically, the movable mirror 50B rotates around the central axis C, thereby sequentially bringing the multiple reflecting surfaces 50a face the sample S. As a result, the light L from the sample S is sequentially reflected by the multiple reflecting surfaces 50a.

[0061] Next, the image acquisition operation by the image acquisition device 1 will be described with reference to Fig. 10. Fig. 10 is a diagram for explaining an example of the operation of the light deflection unit 42 according to the third example. The horizontal axis of the upper graph in Fig. 10 represents time, and the vertical axis represents the intensity I of the irradiated light L0 from the light output unit 3. The horizontal axis of the lower graph in Fig. 10 represents time, and the vertical axis represents the rotation angle θ2 of the reflecting surface 50a that reflects the light L from the sample S. First, in the image acquisition device 1, an image of the sample S is acquired during the image acquisition period T, as in the first embodiment.

[0062] The control unit 8 continues to rotate the movable mirror 50B in the same direction during the image acquisition period T. Specifically, the control unit 8 rotates the movable mirror 50B during an imaging period T1 in the image acquisition period T so that light from the same region of the sample S is incident on the same region of the imaging surface 5a of the image sensor 5. As a result, light from a portion S2 of the sample S is imaged on the imaging surface 5a, and an optical image S20 of the portion S2 of the sample S is generated on the imaging surface 5a.

[0063] Following the imaging period T1, the control unit 8 continues to rotate the movable mirror 50B over the non-imaging period T2 in the image acquisition period T. Specifically, the control unit 8 continues to rotate the movable mirror 50B in one direction so that, in the next imaging period T1, light from the same region on the sample S is incident on the same region on the imaging surface 5a of the image sensor 5. For example, the control unit 8 rotates the movable mirror 50B so that the movable mirror 50B rotates 360 degrees during one set of the imaging period T1 and the non-imaging period T2.

[0064] During the non-imaging period T2, the control unit 8 rotates the movable mirror 50B in one direction so that the reflecting surface 50a that reflects the light L from the sample S is changed to another reflecting surface 50a. In the graph shown in Fig. 13, the reflecting surface 50a that reflects the light L from the sample S is switched to the next reflecting surface 50a, thereby allowing the rotation angle θ2 of the reflecting surface 50a to be instantaneously changed.

[0065] This modification of the first embodiment also achieves the same effects as those of the first embodiment. Furthermore, in this modification, the control unit 8 continues to rotate the movable mirror 50B (optical element) in the same rotational direction during the image acquisition period T. In this case, compared to, for example, oscillating the movable mirror 50B (rotating in one direction and the other), the angular velocity of the movable mirror 50B does not need to be reduced, and the angular velocity of the movable mirror 50B can be increased. This allows for a faster image capture of the entire sample S. In the above example, the field of view position of the objective lens 41 was described as moving in the same direction (to the right in FIG. 9 ) throughout the entire image acquisition period T. Therefore, it can be considered that the control unit 8 continues to rotate the movable mirror 50B in the same direction while the field of view position of the objective lens 41 moves in a predetermined direction (the same direction) during the image acquisition period T. [Second Embodiment]

[0066] The light-guiding optical system 4 of the image acquisition device 1 according to the second embodiment will be described with reference to FIGS. 11 and 12 . FIG. 11 is a schematic diagram showing a fourth example of the light-guiding optical system 4. FIG. 12 is a schematic diagram showing a fifth example of the light-guiding optical system 4. In the examples shown in FIGS. 11 and 12 , the light deflection unit 42 is a refractive optical element 150 (optical element) that refracts light. The refractive optical element 150 deflects light L from the sample S that has passed through the objective lens 41 by refracting it. As in the first embodiment, the movement direction of the sample S in FIGS. 11 and 12 is referred to as D1, and the arrangement direction of multiple pixel rows Q on the imaging surface 5 a is referred to as direction D3. In the second embodiment, the direction along the path of light L from the sample S is referred to as direction D4, and directions perpendicular to direction D4 and perpendicular to each other are referred to as directions D5 and D6.

[0067] In FIG. 11 , the refractive optical element 150 is disposed between the imaging lens 43 and the imaging surface 5a on the optical path of the light L from the sample S. The refractive optical element 150 is disposed at a position where the light L from the sample S is converted into convergent light by the imaging lens 43 (see FIG. 4 ). The refractive optical element 150 is a flat plate 150A (parallel plate) having a pair of parallel principal surfaces 150a. The light L that passes through the imaging lens 43 is incident on one of the principal surfaces 150a. The light L that is incident on one of the principal surfaces 150a passes through the flat plate 150A and exits from the other principal surface 150a. The flat plate 150A is formed, for example, from a material that transmits the light L from the sample S (such as borosilicate glass (BK7)).

[0068] The flat plate 150A is rotatable about a central axis extending along direction D6. The rotation angle θ3 of the flat plate 150A is the tilt angle of the flat plate 150A with respect to direction D5. By changing the rotation angle θ3 of the flat plate 150A, when the light L is refracted by the flat plate 150A, the light L shifts along direction D5. This allows the focusing position P50 of the light L on the imaging surface 5a to be shifted along direction D3. In the example shown in FIG. 11 , rotating the flat plate 150A counterclockwise allows the light L to be shifted to one side in direction D5, and the focusing position P50 of the light L to one side in direction D3 on the imaging surface 5a.

[0069] Fig. 13 is a graph showing the results of a simulation of the relationship between the rotation angle θ3 of the flat plate 150A and the shift amount of the optical image of the sample S on the imaging surface 5a of the image sensor 5. The horizontal axis of Fig. 13 represents the rotation angle θ3 of the flat plate 150A, and the vertical axis of Fig. 13 represents the shift amount of the imaging position of the optical image of the sample S formed on the imaging surface 5a of the image sensor 5. Graphs G1 to G5 are graphs showing the above relationship in the image acquisition device 1 to which the fourth example of the light-guiding optical system 4 is applied, when the thickness of the flat plate 150A is changed in various ways. The thicknesses of the multiple flat plates 150A corresponding to graphs G1, G2, G3, G4, and G5 are 2 mm, 3 mm, 4 mm, 5 mm, and 6 mm, respectively.

[0070] This will be described with reference to FIGS. 11 and 13. When the rotation angle θ3 of the flat plate 150A is 0 degrees, the pair of principal surfaces 150a are parallel to the direction D5. In this case, the light L from the sample S travels straight along the direction D4 without being refracted by the flat plate 150A. Therefore, the amount of shift in the imaging position of the optical image of the sample S formed on the imaging surface 5a of the image sensor 5 is zero. On the other hand, when the rotation angle θ3 of the flat plate 150A is greater than 0 degrees, the pair of principal surfaces 150a are tilted with respect to the direction D5. In this case, the light L from the sample S is refracted by the pair of principal surfaces 150a of the flat plate 150A and shifts along the direction D5. As a result, the amount of shift in the imaging position of the optical image of the sample S becomes greater than zero.

[0071] 13, as the thickness of the flat plate 150A increases and the distance between the pair of principal surfaces 150a increases, the amount of shift along the direction D5 of the light L from the sample S increases. This increases the amount of shift of the optical image of the sample S relative to the amount of change in the rotation angle θ3 of the flat plate 150A.

[0072] In this example, the control unit 8 controls the flat plate 150A during the image capturing period T1 in the image acquisition period T so that light from the same region on the sample S is incident on the same region on the imaging surface 5a of the image sensor 5. That is, in the example described above, the irradiation position on the imaging surface 5a of the light L from the sample S is controlled by controlling the rotation angle of the movable mirror 50A, but in this example, the irradiation position on the imaging surface 5a of the light L from the sample S is controlled by controlling the rotation angle of the flat plate 150A.

[0073] The light-guiding optical system 4 according to the fifth example is an optical system having a parallel light path portion P1. The parallel light path portion P1 is a portion through which light L travels as parallel light. The "portion through which light travels as parallel light" refers to a portion through which light travels with all of the light rays contained in the light parallel to one another. The parallel light path portion P1 will be described in detail with reference to FIG. 4 . Light L1, L2, and L3 (L) from the sample S pass through the objective lens 41 and the imaging lens 43 to reach the imaging surface 5a (imaging unit) of the image sensor 5. The optical axis direction of the parallel light path portion P1 is parallel to a straight line (optical axis) passing through the center C41 of the objective lens 41 and the center C43 of the imaging lens 43, e.g., direction D2. The light L1, L2, and L3 from the sample S are light from different positions T10, T20, and T30 on the sample S, respectively. The light beams L1, L2, and L3 travel as parallel light beams between the objective lens 41 and the imaging lens 43, and as convergent light beams between the imaging lens 43 and the imaging surface 5a. In this case, the light beam L1 travels parallel to the direction D2 in the parallel optical path portion P1. The light beams L2 and L3 travel in a direction intersecting the direction D2 in the parallel optical path portion P1. In this way, the light beam L traveling as parallel light in the parallel optical path portion P1 may travel parallel to the optical axis direction of the parallel optical path portion P1, or may travel in a direction intersecting the optical axis direction of the parallel optical path portion P1.

[0074] 12 , in the light-guiding optical system 4 according to the fifth example, the objective lens 41 receives light L from the sample S and then outputs the light L traveling as parallel light to the parallel light path portion P1. In this way, in this example, the light L from the sample S is collimated by the objective lens 41 to become parallel light (collimated light). The light L output to the parallel light path portion P1 passes through the refractive optical element 150 and is incident on the imaging lens 43. The imaging lens 43 collects the light L from the refractive optical element 150. For example, the imaging lens 43 forms an image of the light L from the refractive optical element 150.

[0075] The refractive optical element 150 is a prism section 150B that refracts light L. The prism section 150B is arranged in the parallel light path portion P1. The prism section 150B is arranged between the imaging lens 43 and the objective lens 41 on the optical path of the light L from the sample S. The prism section 150B deflects the light L from the sample S that has passed through the objective lens 41 by refracting it.

[0076] The prism portion 150B will now be described. The prism portion 150B has a first prism 151 and a second prism 152 aligned along direction D4. Light L traveling as parallel light is incident on the prism portion 150B. The light L that passes through the prism portion 150B is emitted toward the imaging lens 43.

[0077] The first prism 151 includes a first surface 151a and a second surface 151b inclined relative to the first surface 151a. Light L from the sample S is incident on the first surface 151a of the first prism 151. The light L incident from the first surface 151a passes through the first prism 151 and exits from the second surface 151b. The first prism 151 refracts the light L from the sample S at at least one of the first surface 151a and the second surface 151b. The first prism 151 is formed of, for example, a material (such as borosilicate glass (BK7)) that transmits the light L from the sample S.

[0078] The second prism 152 includes a third surface 152a and a fourth surface 152b inclined relative to the third surface 152a. Light L from the first prism 151 is incident on the third surface 152a of the second prism 152. The light L incident on the third surface 152a passes through the second prism 152 and exits from the fourth surface 152b. The second prism 152 refracts the light L from the sample S at at least one of the third surface 152a and the fourth surface 152b. The second prism 152 is formed of, for example, a material (such as borosilicate glass (BK7)) that transmits the light L from the sample S. The second prism 152 may be the same prism as the first prism 151, or may be a different prism from the first prism 151.

[0079] The inclination angle of the second surface 151b relative to the first surface 151a corresponds to the inclination angle of the fourth surface 152b relative to the third surface 152a. For example, the inclination angle of the second surface 151b relative to the first surface 151a is substantially the same as the inclination angle of the fourth surface 152b relative to the third surface 152a.

[0080] The first prism 151 is rotatable about a central axis extending along direction D6. The rotation angle θ4 is the tilt angle of the first surface 151a of the first prism 151 with respect to the horizontal direction (e.g., direction D1) (see FIG. 14 ). The orientation of the first prism 151 relative to the second prism 152 changes depending on the rotation angle θ4 of the first prism 151. Specifically, when the rotation angle θ4 of the first prism 151 is 0 degrees (see FIG. 12 ), the second surface 151b is located on the second prism 152 side, and the first surface 151a is located on the opposite side from the second prism 152. The third surface 152a is located on the first prism 151 side, and the fourth surface 152b is located on the opposite side from the first prism 151. The first surface 151a is parallel to the fourth surface 152b, and the second surface 151b is parallel to the third surface 152a. In this case, the first prism 151 and the second prism 152 are positioned so as to form a parallelogram-shaped (rectangular in this example) flat plate (parallel flat plate) when they are brought close to each other along direction D4 and the second surface 151 b and the third surface 152 a are brought into contact with each other. The first prism 151 can rotate 360 ​​degrees around the central axis.

[0081] The first prism 151 refracts the light L from the sample S at at least one of the first surface 151a and the second surface 151b. Specifically, the first surface 151a and the second surface 151b refract the light L when the light L is incident at an angle other than 90 degrees. In the example shown in FIGS. 14(a) and 14(b), the first prism 151 refracts the light L from the sample S at both the first surface 151a and the second surface 151b. In the example shown in FIG. 12, the incident angle of the light L from the sample S at the first surface 151a of the first prism 151 is 90 degrees, so the first prism 151 does not refract the light L from the sample S at the first surface 151a but refracts the light L from the sample S at the second surface 151b.

[0082] The second prism 152 refracts the light L from the sample S at at least one of the third surface 152a and the fourth surface 152b. Specifically, the third surface 152a and the fourth surface 152b refract the light L when the light L is incident at an angle other than 90 degrees. In the example shown in FIGS. 14(a) and 14(b), the second prism 152 refracts the light L from the sample S at both the third surface 152a and the fourth surface 152b. In the example shown in FIG. 12, the incident angle of the light L from the sample S at the fourth surface 152b of the second prism 152 is 90 degrees, so the second prism 152 does not refract the light L from the sample S at the fourth surface 152b but refracts the light L from the sample S at the third surface 152a.

[0083] According to the light-guiding optical system 4 described above, by changing the rotation angle θ4 of the first prism 151, when the light L is refracted at the prism portion 150B, the light L shifts along the direction D5. This allows the focusing position P50 of the light L on the imaging surface 5a to be shifted along the direction D3. For example, by rotating the first prism 151 counterclockwise, the focusing position P50 of the light L can be shifted to one side in the direction D3 on the imaging surface 5a. Furthermore, for example, by rotating the first prism 151 clockwise, the focusing position P50 of the light L can be shifted to the other side in the direction D3 on the imaging surface 5a.

[0084] 14 is a diagram for explaining the operation of the light deflection unit 42, which is the prism unit 150B. For the sake of explanation, the imaging surface 5a is shown facing the front side of the page in FIG. 14. Only one divided region R out of the multiple divided regions R shown in FIG. 1 is shown in FIG.

[0085] 14, the control unit 8 controls the light deflection unit 42 in accordance with (in synchronization with) the movement of the sample S. Specifically, the control unit 8 controls the rotation angle θ4 of the first prism 151 so that the first surface 151a of the first prism 151 follows the sample S. In the example shown in FIG. 14, the control unit 8 changes the rotation angle θ4 of the first prism 151 in synchronization with the movement of the sample S, thereby directing the light LA ​​from the region A in the divided region R to one pixel row Q (in this example, the second pixel row Q) on the imaging surface 5a of the image sensor 5 over the imaging period T1.２ ) on the imaging surface 5a. ２ ) continues to be incident on

[0086] First, as shown in FIG. 14A, light LA ​​from the region A in the divided region R is incident on the second pixel row Q on the imaging surface 5 a of the imaging element 5 during the imaging period T1. ２ 14(b), as the sample S moves, the first prism 151 rotates so that the first surface 151a follows the sample S. Finally, as shown in FIG. 14(c), as the sample S moves further, the prism unit 150B further rotates so that the first surface 151a follows the sample S. In this way, the control unit 8 controls the prism unit 150B by rotating the first prism 151 of the prism unit 150B in synchronization with the movement of the sample S. As a result, the light LA ​​from the same region (region A) on the sample S is guided to the same region (second pixel row Q) on the imaging surface 5a. ２ ) is continuously incident on the imaging surface 5a. As a result, although the sample S is moving, the light L from the sample S can be prevented from moving on the imaging surface 5a.

[0087] Next, a simulation result of the change in the shift amount of the optical image of the sample S on the imaging surface 5a of the image sensor 5 with respect to the change in the rotation angle θ4 of the first prism 151 will be described. FIGS. 15 and 16 are graphs showing the simulation result of the relationship between the rotation angle θ4 of the first prism 151 and the shift amount of the optical image of the sample S on the imaging surface 5a of the image sensor 5. The horizontal axis of FIG. 15 represents the rotation angle θ4 of the first prism 151, and the vertical axis of FIG. 15 represents the shift amount of the optical image of the sample S on the imaging surface 5a of the image sensor 5. FIG. 16 is a graph in which the first quadrant of the graph shown in FIG. 15 is enlarged. Graphs G6 to G9 are graphs showing the above-mentioned relationship in the image acquisition device 1 when the tilt angle of the second surface 151b with respect to the first surface 151a in the prism portion 150B is changed in various ways. The inclination angles of the plurality of first prisms 151 corresponding to the graphs G6, G7, G8, and G9 are 1 degree, 2 degrees, 3 degrees, and 5 degrees, respectively.

[0088] 15 and 16 , the shift amount of the optical image of the sample S on the imaging plane 5a changes nonlinearly with the rotation angle θ4 of the first prism 151. As the rotation angle θ4 of the first prism 151 changes, the shift amount of the optical image of the sample S decreases and then increases. As such, the sensitivity of the shift amount of the optical image of the sample S to the change in the rotation angle θ4 of the first prism 151 depends on the absolute value of the rotation angle θ4 of the first prism 151. For example, when comparing the cases where the rotation angle θ4 of the first prism 151 is 0 degrees or greater and 1 degree or less (part G91 of graph G9), 2 degrees or greater and 3 degrees or less (part G92 of graph G9), and 5 degrees or greater and 6 degrees or less (part G93 of graph G9), the shift amount of the imaging position of the optical image with respect to the change in the rotation angle θ4 of the first prism 151 increases as the rotation angle θ4 of the first prism 151 increases. This makes it possible to adjust the sensitivity of the shift amount of the optical image's imaging position relative to the change in the rotation angle θ4 of the first prism 151 by appropriately selecting the range of the rotation angle θ4 of the first prism 151 used to adjust the optical image's imaging position.

[0089] The sensitivity of the shift amount of the optical image of the sample S with respect to the change in the rotation angle θ4 of the first prism 151 also depends on the tilt angle of the second surface 151b with respect to the first surface 151a. The larger the tilt angle of the second surface 151b with respect to the first surface 151a of the first prism 151, the larger the shift amount of the optical image of the sample S with respect to the rotation angle θ4 of the first prism 151.

[0090] Next, with reference to FIGS. 17 and 18 , the operation of the prism unit 150B in response to movement of the field of view position P of the objective lens 41 in the image acquisition device 1 according to the embodiment will be described. FIG. 17( a) is a schematic diagram showing an example of movement of the field of view position P of the objective lens 41. FIG. 17( b) is a schematic diagram showing another example of movement of the field of view position P of the objective lens 41. In the example shown in FIGS. 17( a) and 17(b), the sample S has a rectangular shape. One side of the sample S in the longitudinal direction is the X1 side, and the other side of the sample S in the longitudinal direction is the X2 side. One side of the sample S in the lateral direction is the X3 side, and the other side of the sample S in the lateral direction is the X4 side. FIG. 18( a) is a diagram showing an example of the prism unit 150B. Fig. 18(b) is a graph showing the simulation results of the relationship between the rotation angle θ4 of the first prism 151 and the shift amount of the optical image of the sample S on the imaging surface 5a of the image sensor 5. The horizontal axis of Fig. 18(b) represents the rotation angle θ4 of the first prism 151, and the vertical axis of Fig. 18(b) represents the shift amount of the optical image of the sample S on the imaging surface 5a of the image sensor 5.

[0091] First, the movement of the field of view position P of the objective lens 41 will be described. In the example shown in Fig. 17(a) , the stage 2 is moved so as to move the field of view position P of the objective lens 41 toward the X1 side. When one movement is completed, the stage 2 is moved so that the field of view position P of the objective lens 41 moves a predetermined distance toward the X4 side. This allows the field of view position P of the objective lens 41 to be repeatedly moved toward the X1 side while the field of view position P of the objective lens 41 is sequentially moved toward the X4 side (single-axis scanning).

[0092] 17(b), the stage 2 is moved so that the field of view position P of the objective lens 41 is moved alternately toward the X1 side and the X2 side. At the timing when one movement toward the X1 side or the X2 side is completed, the stage 2 is moved so that the field of view position P of the objective lens 41 is moved a predetermined distance toward the X4 side. In this way, the reciprocating movement of the field of view position P of the objective lens 41 can be repeatedly performed while sequentially moving the field of view position P of the objective lens 41 toward the X4 side (reciprocating scan).

[0093] Next, the operation of the prism unit 150B will be described. In the example shown in FIG. 18( a), the first prism 151 rotates clockwise. At this time, in the graph shown in FIG. 18( b), the numerical values ​​on the horizontal axis change from the left side of the page to the right side of the page (in the direction A1 in FIG. 18( b)). In the example shown in FIG. 18( b), when the rotation angle θ4 increases in the first range RP, which is the range in which the rotation angle θ4 is positive, the shift amount of the optical image of the sample S increases. When the rotation angle θ4 increases in the second range RN, which is a predetermined range in which the rotation angle θ4 is negative, the shift amount of the imaging position of the optical image decreases.

[0094] Finally, we will explain the operation of the prism unit 150B in response to the movement of the field of view position P. For example, when the control unit 8 moves the field of view position P of the objective lens 41 toward the X1 side (see FIGS. 17A and 17B), the control unit 8 irradiates the sample S with the illumination light L0 while increasing the rotation angle θ4 in the first range RP (see FIG. 18B). This allows the control unit 8 to move the field of view position P of the objective lens 41 toward the X1 side while causing light from the same region on the sample S to be incident on the same region on the imaging surface 5 a of the image sensor 5.

[0095] Furthermore, for example, when the control unit 8 moves the field of view position P of the objective lens 41 toward the X2 side (see FIG. 17B), the control unit 8 irradiates the sample S with the illumination light L0 while increasing the rotation angle θ4 in the second range RN (see FIG. 18B). In this way, the control unit 8 can move the field of view position P of the objective lens 41 toward the X2 side while causing light from the same region on the sample S to be incident on the same region on the imaging surface 5 a of the image sensor 5.

[0096] As described above, the timing of irradiating the illumination light L0 (the phase of the LED light emission cycle) is controlled while rotating the first prism 151 in one direction (at a constant speed). This allows light from the same region on the sample S to be incident on the same region on the imaging surface 5a of the imaging element 5 while rotating the first prism 151 in one direction, and allows the sample S on the stage 2 to be scanned in one of the X1 side and the X2 side, or in both the X1 side and the X2 side. [Functions and Effects of the Second Embodiment]

[0097] As with the first embodiment, the image acquisition device 1 according to the second embodiment can acquire clear images while suppressing image blur. Furthermore, the flat plate 150A or the prism portion 150B (light deflection portion 42) deflects the light L from the sample S that has passed through the objective lens 41 by refracting it, and the control portion 8 rotates the flat plate 150A or the prism portion 150B during an imaging period T1 (a predetermined period) during the image acquisition period T so that light from the same region on the sample S is incident on the same region on the imaging surface 5a of the image sensor 5. In this case, the light deflection portion 42 can be configured by the flat plate 150A or the prism portion 150B that refracts the light L.

[0098] The flat plate 150A (optical element) is disposed between the imaging lens 43 and the image sensor 5 on the optical path of the light L from the sample S. In this case, by adjusting the material or thickness of the flat plate 150A, it is possible to adjust the sensitivity of the amount of change in the position of the optical image formed on the imaging surface 5a of the image sensor 5 relative to the amount of change in the rotation angle θ3 of the flat plate 150A. Furthermore, since this sensitivity is relatively low compared to when the light deflection unit 42 is formed by, for example, a reflective optical element 50 on which a reflective surface 50a is formed, it is possible to easily control the amount of change in the position of the optical image by controlling the rotation angle of the flat plate 150A (control of the rotation angle).

[0099] The prism portion 150B (optical element) is disposed between the objective lens 41 and the imaging lens 43 on the optical path of the light L from the sample S. In this case, by adjusting the material or thickness of the prism portion 150B, it is possible to adjust the sensitivity of the change in the imaging position of the optical image formed on the imaging surface 5a of the image sensor 5 to the change in the rotation angle θ4 of the first prism 151. Furthermore, since this sensitivity is relatively low compared to when the optical deflection portion 42 is formed by, for example, a reflective optical element 50 on which a reflective surface 50a is formed, it is possible to easily control the amount of change in the position of the optical image by controlling the rotation angle of the prism portion 150B (control of the rotation angle). [Modification]

[0100] Fig. 19 is a schematic diagram showing an image acquisition device 1 according to a modified example. As shown in Fig. 19, the image acquisition device 1 may include a plurality of filters 10. The plurality of filters 10 are disposed on the imaging surface 5a of the image sensor 5 and extend parallel to the imaging surface 5a. The plurality of filters 10 are lined up along direction D3.

[0101] During an imaging period T1 in the image acquisition period T, light L from the sample S is imaged in each of the regions on the imaging surface 5a of the image sensor 5 corresponding to each of the multiple filters 10. Specifically, the multiple filters 10 are composed of filters 10A, 10B, and 10C. A light image S20A of a first portion S2A of a portion S2 of the sample S is imaged by the region corresponding to filter 10A. A light image S20B of a second portion S2B of the portion S2 of the sample S is imaged by the region corresponding to filter 10B. A light image S20C of a third portion S2C of the portion S2 of the sample S is imaged by the region corresponding to filter 10C.

[0102] Here, three consecutive imaging periods T1 are set at predetermined time intervals corresponding to the widths of the multiple filters 10 in the direction D3. This allows the sample S to be imaged through each of the multiple filters 10A, 10B, and 10C. For example, in the first imaging, light generated from a first portion S2A of a portion S2 of the sample S and passed through the filter 10A is imaged. In the second imaging, light generated from the first portion S2A of the portion S2 of the sample S and passed through the filter 10B is imaged. In the third imaging, light generated from the first portion S2A of the portion S2 of the sample S and passed through the filter 10C is imaged. Then, a superimposed image is obtained by superimposing the multiple images obtained by imaging the sample S.

[0103] When three filters 10 are arranged for three regions on the imaging surface 5 a of the imaging element 5, the imaging frequency needs to be tripled in order to image the entire sample S in one region, and therefore the rotation speed of the light deflection unit 42 (the frequency of the waveform in the graph shown in FIG. 10 ) needs to be tripled.

[0104] The multiple filters 10 have different filter characteristics. Figures 20(a) and 20(b) are diagrams showing an example of the multiple filters 10. In the example shown in Figures 20(a) and 20(b), the multiple filters 10 are color filters that transmit light of different wavelength bands. For example, filter 10A is a filter that transmits red light, filter 10B is a filter that transmits green light, and filter 10C is a filter that transmits blue light. This makes it possible to obtain a superimposed image with higher resolution and color reproducibility than when, for example, a mosaic filter is used.

[0105] 21(a) and 21(b) are diagrams showing another example of the multiple filters 10. In the example shown in FIGS. 21(a) and 21(b), the multiple filters 10 have different thicknesses. For example, filter 10A is the filter with the greatest thickness, filter 10B is the filter with the second greatest thickness, and filter 10C is the filter with the smallest thickness. The multiple filters 10 can each adjust the optical path length between the sample S and the imaging surface 5a of the image sensor 5. This allows the observation depth in the sample to be changed in the superimposed image.

[0106] According to the image acquisition device 1 of the modified example, light transmitted through a plurality of filters 10 with different filter characteristics can be captured by the image sensor 5. For example, if the plurality of filters 10 transmit light in different wavelength bands, an image with higher resolution and color reproducibility can be acquired. Alternatively, for example, if the plurality of filters 10 have different thicknesses, the optical path lengths of the transmitted light can be made different from one another, and the observation depth in the sample S can be changed.

[0107] A further modification of the image acquisition device 1 to which the third example of the light-guiding optical system 4 shown in FIG. 9 is applied will be described. FIG. 22 is a diagram showing another example of the image acquisition device 1 to which the third example of the light-guiding optical system 4 is applied. As shown in FIG. 22, the image acquisition device 1 may further include a detection unit 9 that detects the position of the reflecting surface 50a that reflects the light L from the sample S. The detection unit 9 has a light output unit 9a, a slit 9b, and a light detection unit 9c. The light output unit 9a irradiates the reflecting surface 50a that reflects the light L from the sample S with the detection light Ld. The light output unit 9a is, for example, a semiconductor light-emitting element such as an LD (laser diode). The slit 9b allows only the detection light Ld reflected by the reflecting surface 50a at a predetermined angle to pass through. The slit 9b extends along a direction perpendicular to the direction D2. The light detection unit 9c detects the detection light Ld that has passed through the slit 9b.

[0108] In the image acquisition device 1, the timing of capturing images by the image sensor 5 is controlled based on the detection result of the detection unit 9. Specifically, in the image acquisition device 1, when the detection unit 9 detects that the position of the reflective surface 50a is at a predetermined position, the image sensor 5 starts capturing images. In the example shown in Fig. 22, at the timing when the detection unit 9 detects that the position of the reflective surface 50a is at a predetermined position, the light output unit 3 starts outputting the irradiated light L0, and the image capturing period T1 starts. As a result, the light L reflected at a desired reflection angle for each reflective surface 50a can be captured by the image sensor 5.

[0109] The detection unit 9 detects the position of the reflecting surface 50a that reflects the light L from the sample S. Then, the timing of imaging by the image sensor 5 is controlled based on the detection result of the detection unit 9. In this case, even if the rotation speed of the movable mirror 50B (optical element) is unstable, for example, the imaging timing can be reliably controlled based on the detection result of the detection unit 9. Additionally, in the image acquisition device 1, the movable mirror 50B (optical element) is formed with a plurality of reflecting surfaces 50a, and the movable mirror 50B is rotated to sequentially reflect the light L from the sample S at the plurality of reflecting surfaces 50a. This allows the imaging timing to be synchronized among the plurality of reflecting surfaces 50a, even if there are differences in shape among the plurality of reflecting surfaces 50a due to, for example, machine precision during manufacturing.

[0110] The present invention is not limited to the first embodiment, the second embodiment, and the modified examples. For example, in the image acquisition device 1, the image sensor 5 has a plurality of pixel rows Q, but is not limited to this. The image sensor 5 only needs to have one or more pixels, and may have, for example, only one pixel row or only one pixel.

[0111] In the image acquisition device 1, the light output unit 3 outputs the irradiated light L0 for a time longer than the reference time or for a time at least twice the reference time, but this is not limiting. For example, the irradiated light L0 may be output for a time shorter than the reference time.

[0112] In the image acquisition device 1, the control unit 8 controls the light deflection unit 42 during the imaging period T1 so that light from the same region of the sample S is incident on the same pixel on the imaging surface 5a of the image sensor 5, but the control unit 8 may also control the light deflection unit 42 during the imaging period T1 so that light from the same region of the sample S is incident on multiple pixels on the imaging surface 5a of the image sensor 5. In this case, the control unit 8 regards the multiple pixels as one pixel to generate the captured image.

[0113] In the image acquisition device 1, the light deflection unit 42 is the reflective optical element 50 that deflects the light L from the sample S by reflecting it on the reflecting surface 50 a, or the refractive optical element 150 that deflects the light L from the sample S by refracting it, but is not limited to this. The light deflection unit 42 may be any optical element other than those described above as long as it can deflect the light L from the sample S.

[0114] In the image acquisition device 1, the light-guiding optical system 4 includes the imaging lens 43 that focuses the light L from the sample S on the imaging surface 5a of the image sensor 5, but is not limited to this. In the light-guiding optical system 4, it is sufficient that the light L that has passed through the objective lens 41 and the light deflection unit 42 is guided to the image sensor 5. For example, it is sufficient that the light-guiding optical system 4 includes at least the objective lens 41 and the light deflection unit 42.

[0115] In the control examples described with reference to FIGS. 9 and 10 , the field of view position of the objective lens 41 moves in the same direction (to the right in FIG. 9 ) throughout the entire image acquisition period T. However, as in the reciprocating scan described with reference to FIG. 17( b ), the movement direction of the field of view position P of the objective lens 41 may be changed during the image acquisition period T. In this case, the control unit 8 may rotate the movable mirror 50B (optical element) in a rotation direction corresponding to the movement direction of the field of view position P during the image acquisition period T. As a result, according to the image acquisition device 1, it is not necessary to decelerate the angular velocity of the movable mirror 50B, and therefore the angular velocity of the movable mirror 50B can be increased, compared to, for example, a case in which the movable mirror 50B is oscillated (the rotation direction of the optical element is changed) while the field of view position P of the objective lens 41 moves in a predetermined direction during the image acquisition period T.

[0116] For example, the control unit 8 may rotate the movable mirror 50B in a first direction while the field of view position P is moving in one direction (e.g., toward X1 in FIG. 17(b)), and may rotate the movable mirror 50B in a second direction opposite to the first direction while the field of view position P is moving in the other direction (e.g., toward X2 in FIG. 17(b)). In this way, even when the direction of movement of the field of view position P of the objective lens 41 is changed during the image acquisition period T, the control unit 8 may continue to rotate the movable mirror 50B in the same direction while the field of view position of the objective lens 41 is moving in a predetermined direction (the same direction) during the image acquisition period T.

[0117] In the image acquisition device 1, the control unit 8 continuously oscillates the light deflection unit 42 during the image acquisition period T, or continuously rotates the light deflection unit 42 in the same rotational direction during the period in which the field of view position P of the objective lens 41 moves in a predetermined direction during the image acquisition period T, but this is not limiting. The control unit 8 only needs to control the light deflection unit 42 so that light from the same region on the sample S is incident on the same region on the imaging surface 5 a of the image sensor 5 during the imaging period T1 in the image acquisition period T.

[0118] In the image acquisition device 1, the light output unit 3 switches the output of the irradiating light L0 on and off by controlling the on and off of the light source 3a, but the light output unit 3 may also switch the output of the irradiating light L0 on and off by controlling the opening and closing of an electronic shutter.

[0119] In the image acquisition device 1, the first prism 151 is rotatable about a central axis extending along the direction D6. However, it is sufficient that at least one of the first prism 151 and the second prism 152 is rotatable about a central axis extending along the direction D6. For example, the second prism 152 may be rotatable about a central axis extending along the direction D6. In this case, by refracting the light L from the sample S at at least one of the third surface 152a and the fourth surface 152b of the second prism 152, the light L from the sample S can be shifted along the direction D5 by the second prism 152. Then, the light L from the sample S is refracted at at least one of the first surface 151a and the second surface 151b of the first prism 151. As a result, dispersion caused by refraction at the second prism 152 can be reduced by refraction at the first prism 151.

[0120] In the image acquisition device 1, the driving unit 6 moves the stage 2, but this is not limiting. The driving unit 6 may move the field of view position P of the objective lens 41 relative to the sample S. For example, the driving unit 6 may move the light-guiding optical system 4, or may move both the stage 2 and the light-guiding optical system 4.

[0121] FIG. 23 is a diagram showing a modified example of the fifth example of the light-guiding optical system 4. As shown in FIG. 23 , in the light-guiding optical system 4, the imaging lens 43 may be movable along direction D5 (a direction orthogonal to the optical axis A43 of the imaging lens 43 (a direction intersecting the traveling direction of the light L from the sample S)) so that the light L from the objective lens 41 passes through the center C43 of the imaging lens 43. The image sensor 5 may be movable in direction D5 (a direction along the imaging surface 5 a) in accordance with the movement of the imaging lens 43 so that light from the same region of the sample S is incident on the same region on the imaging surface 5 a of the image sensor 5. In this case, for example, even when the light L output from the light-guiding optical system 4 is shifted along direction D5, the light L from the objective lens 41 passes through the center C43 of the imaging lens 43, thereby improving the imaging performance.

[0122] In this modification, the imaging lens 43 is movable along a direction perpendicular to the optical axis A43 of the imaging lens 43, but this is not limiting. The imaging lens 43 may be movable along a direction intersecting the optical axis A43 of the imaging lens 43. Furthermore, the imaging surface 5a is movable along the direction D5, but may be movable along any direction along the imaging surface 5a. For example, as shown in FIG. 6 , the light L from the sample S may reach the imaging surface 5a with the traveling direction of the light L changed by a reflective surface such as a mirror (e.g., the reflective surface 50a of the movable mirror 50A). In such a case, the imaging surface 5a may be movable in a direction intersecting the traveling direction of the light L from the sample S reaching the imaging surface 5a, for example, along the direction D3 shown in FIG.

[0123] 23 , the light-guiding optical system 4 further includes a movement mechanism 90 that is capable of moving the imaging lens 43 and the imaging surface 5 a of the image sensor 5 along direction D5. Based on the shift amount of the light L from the optical axis A41, the control unit 8 controls the position of the imaging lens 43 in direction D5 via the movement mechanism 90 so that the light L from the prism unit 150B passes through the center C43 of the imaging lens 43. The control unit 8 controls the position of the imaging surface 5 a in direction D5 so as to cancel out the movement of the focusing position of the light L from the sample S that corresponds to the movement of the imaging lens 43.

[0124] Furthermore, in this modification, the imaging lens 43 is movable along a direction intersecting the traveling direction of the light L from the sample S, but it is sufficient that at least one of the objective lens 41 and the imaging lens 43 is movable along a direction intersecting the traveling direction of the light L from the sample S. In this case, it is sufficient that the image sensor 5 is movable in a direction along the imaging surface 5 a in accordance with the movement of at least one of the objective lens 41 and the imaging lens 43 so that light from the same region of the sample S is incident on the same region on the imaging surface 5 a of the image sensor 5.

[0125] For example, the objective lens 41 may be movable in a direction intersecting the optical axis A41 of the objective lens 41 (a direction intersecting the traveling direction of the light L from the sample S). In this case, the image sensor 5 is movable in a direction D5 (a direction along the image sensor surface 5 a) in accordance with the movement of the objective lens 41 so that light from the same region of the sample S is incident on the same region of the image sensor surface 5 a.

[0126] Furthermore, for example, both the objective lens 41 and the imaging lens 43 may be movable along a direction intersecting the traveling direction of the light L from the sample S. In this case, the objective lens 41 is movable in a direction intersecting the optical axis A41 of the objective lens 41, and the imaging lens 43 is movable in a direction intersecting the optical axis A43 of the imaging lens 43. The image sensor 5 is movable in direction D5 (a direction along the imaging surface 5a) in accordance with the movement of both the objective lens 41 and the imaging lens 43, so that light from the same region of the sample S is incident on the same region on the imaging surface 5a of the image sensor 5.

[0127] 1...image acquisition device, 2...stage, 3...light output unit, 4...light-guiding optical system, 5...imaging element, 5a...imaging surface, 6...drive unit, 8...control unit, 9...detection unit, 10...filter, 41...objective lens, 42...light deflection unit, 43...imaging lens, 50...reflective optical element (optical element), 50A, 50B...movable mirror, 50a...reflecting surface, 150...refractive optical element (optical element), 150A...flat plate, 150B...prism unit, L...light, L0...irradiation light, P...field of view position, S...sample, T...image acquisition period, T1...imaging period (predetermined period).

Claims

1. An image acquisition device comprising: a stage on which a sample is placed; a light output unit that outputs illumination light to be irradiated onto the sample; a light guiding optical system having an objective lens through which light from the sample passes as the illumination light irradiates the sample, and a light deflection unit that deflects the light from the sample that has passed through the objective lens; an image sensor that images the light from the sample that has been guided by the light guiding optical system; a drive unit that moves the field of view position of the objective lens relative to the sample; and a control unit that controls the light deflection unit, wherein during an image acquisition period, the drive unit moves the field of view position of the objective lens relative to the sample while the illumination light is output from the light output unit and the light from the sample is imaged by the image sensor, and the control unit controls the light deflection unit so that light from the same region of the sample is incident on the same region on the imaging surface of the image sensor during a predetermined period during the image acquisition period.

2. The image acquisition device according to claim 1, wherein the imaging element has a plurality of pixels, and the time taken for the field of view position to move by an amount corresponding to one of the pixels is defined as a reference time, and the light output unit outputs the irradiation light for a time longer than the reference time during the specified period.

3. The image acquisition device according to claim 2, wherein the light output unit outputs the irradiation light for a time period that is at least twice as long as the reference time during the predetermined period.

4. An image acquisition device according to any one of claims 1 to 3, wherein the light deflection unit includes an optical element having a reflective surface formed thereon, and deflects light from the sample that has passed through the objective lens by reflecting it on the reflective surface, and the control unit rotates the optical element so that light from the same area on the sample is incident on the same area on the imaging surface of the imaging element during the specified period.

5. The image acquisition device according to claim 4, wherein the light-guiding optical system further comprises an imaging lens that forms an image of light from the sample that has passed through the objective lens on the imaging surface of the imaging element, and the optical element is disposed between the imaging lens and the imaging element on the path of the light from the sample.

6. The image acquisition device according to claim 4, wherein the light-guiding optical system further comprises an imaging lens that forms an image of light from the sample that has passed through the objective lens on the imaging surface of the imaging element, and the optical element is disposed between the objective lens and the imaging lens on the path of the light from the sample.

7. An image acquisition device according to any one of claims 4 to 6, wherein the control unit continues to rotate the optical element in the same rotational direction while the field of view position of the objective lens moves in a predetermined direction during the image acquisition period.

8. The image acquisition device according to any one of claims 4 to 7, further comprising a detection unit that detects the position of the reflecting surface that reflects light from the sample, and the timing of imaging by the image sensor is controlled based on the detection result of the detection unit.

9. An image acquisition device according to any one of claims 1 to 3, wherein the light deflection unit includes an optical element that refracts light, and deflects the light from the sample that has passed through the objective lens by refracting the light, and the control unit rotates the optical element so that light from the same area on the sample is incident on the same area on the imaging surface of the image sensor during a predetermined period during the image acquisition period.

10. The image acquisition device according to claim 9, wherein the light-guiding optical system further comprises an imaging lens that focuses light from the sample that has passed through the objective lens onto the imaging surface of the imaging element, and the optical element is disposed between the imaging lens and the imaging element on the path of the light from the sample.

11. The image acquisition device according to claim 9, wherein the light-guiding optical system further comprises an imaging lens that forms an image of light from the sample that has passed through the objective lens on the imaging surface of the imaging element, and the optical element is disposed between the objective lens and the imaging lens on the path of the light from the sample.

12. An image acquisition device according to any one of claims 1 to 11, wherein the light-guiding optical system further comprises an imaging lens that images light from the sample that has passed through the objective lens onto the imaging surface of the imaging element, and at least one of the objective lens and the imaging lens is movable along a direction intersecting the direction of travel of light from the sample so that light from the sample that has passed through the objective lens passes through the center of the imaging lens, and the imaging element is movable in a direction along the imaging surface in accordance with movement of at least one of the objective lens and the imaging lens so that light from the same region of the sample is incident on the same region on the imaging surface of the imaging element.

13. An image acquisition device according to any one of claims 1 to 11, further comprising a plurality of filters arranged on the imaging surface of the image sensor so as to be aligned along a direction corresponding to the direction of movement of the field of view position of the objective lens relative to the sample, the plurality of filters having mutually different filter characteristics, and during the predetermined period during the image acquisition period, light from the sample is imaged in each of the areas on the imaging surface of the image sensor corresponding to the plurality of filters.

14. An image acquisition method using an image acquisition device, the image acquisition device comprising: a stage on which a sample is placed; a light output unit that outputs illumination light to be irradiated onto the sample; a light guiding optical system having an objective lens through which light from the sample passes as the illumination light irradiates the sample, and a light deflection unit that deflects the light from the sample that has passed through the objective lens; an image acquisition element that images the light from the sample that has been guided by the light guiding optical system; a drive unit that moves the field of view position of the objective lens relative to the sample; and a control unit that controls the light deflection unit, the image acquisition method including an image acquisition step in which the illumination light is output from the light output unit and the light from the sample is imaged by the image acquisition element while the field of view position of the objective lens relative to the sample is moved by the drive unit, and during a predetermined period of the image acquisition step, the control unit controls the light deflection unit so that light from the same region of the sample is incident on the same region on the imaging surface of the image acquisition element.

Images