Long-stroke vibration-free linear high-speed reciprocating scanning device

Abstract

The present invention relates to a long-stroke vibration-free linear high-speed reciprocating scanning device capable of solving the problem of mechanical vibration when conveying a scanning head.

Description

Wide-range, vibration-free linear high-speed reciprocating scanning device

[0001] The present disclosure relates to a device applicable to both the field of photoacoustic imaging and the general field of mechanical engineering. First, in the field of photoacoustic imaging, the present disclosure relates to a photoacoustic scanner device applicable to small imaging devices such as handheld probes or endoscopic probes that use a single ultrasonic transducer-based mechanical scanning method, and in the field of general mechanical engineering, the present disclosure relates to a scanner device applicable to various fields requiring mechanical reciprocating scanning.

[0002] In general, a photoacoustic imaging device based on a single ultrasonic transducer and mechanical scanning method refers to a device that scans by physically moving some elements directly to obtain a desired image over a certain range according to the photoacoustic imaging principle.

[0003] This type of mechanical scanning method based on a single ultrasonic transducer has the advantage of being able to implement the system much more economically than the electrical scanning method using an array transducer composed of multiple piezoelectric elements, and the advantage of being able to implement the image resolution much higher. Therefore, various forms have been proposed, such as a method that steers only the laser beam using a galvanometer scanner, and a method that steers both the laser beam and ultrasound simultaneously using a MEMS scanner or a polygonal mirror. However, the scanning methods mentioned above are specialized for high-speed scanning, and have the disadvantage of being very narrow in terms of the scanning range (stroke) that can actually acquire an image, typically less than 5 mm.

[0004] However, in order to apply photoacoustic imaging devices to actual clinical practice, there is a requirement that the image scan range must be higher than a preset level as well as the scan speed. In order to meet this requirement, it is clear that there is a fundamental limitation in the operating principle of simply angularly steering only the laser beam or ultrasound beam as in the example mentioned above, as it cannot cover the entire required scan area.

[0005] Therefore, in order to meet this wide range of image scanning capabilities, the relevant field has applied a method of physically moving and scanning the related optical system or ultrasonic transducer mounted on a stage, and most of the systems of this type presented so far have been implemented with a structure that directly guides the laser pulse generated from the light source to the scanning head where the image is actually taken using an optical fiber.

[0006] However, when a mechanical scan is performed over a wider stroke than a few millimeters with the optical fiber for guidance directly connected to the scanning head, the bending of the optical fiber near the scanning head changes from moment to moment, causing the intensity of the laser pulse transmitted by the principle of total internal reflection within the optical fiber to be inconsistent, which ultimately causes fluctuations in the amount of light transmitted to the tissue to be examined. This becomes an even bigger problem as the scan range becomes wider and when performing spectral or functional imaging that requires the use of two or more wavelengths, ultimately making it difficult to obtain accurate quantitative images.

[0007] Of course, when applying a single mode optical fiber with a very fine core of less than 10 μm, the problem of non-uniformity of the light amount mentioned may be somewhat less of a problem, but considering the basic principle that the optical fiber itself transmits light by the principle of total reflection, it is self-evident that changes in the geometric shape will cause changes in the transmission rate, and ultimately, in order to reduce this problem, the scan range must be set very narrowly, such as less than several mm.

[0008] In addition, the problem of optical fiber bending during the mechanical scanning process can cause physical fatigue to the optical fiber and eventually result in the breakage of the optical fiber when performing high-speed scanning over a much wider range than a few millimeters by applying a multimode optical fiber that is much thicker than a single mode. In addition, the elasticity generated as the curvature of the optical fiber changes and the temporal fluctuation of its elastic modulus act as a kind of resistance when increasing the scan speed, which ultimately hinders the increase in the scan speed and reduces the uniformity of the scan speed.

[0009] Accordingly, the present invention proposes a new concept of mechanical scanning device and a photoacoustic scanner structure based on it that can solve all of the problems of non-uniformity of light transmission due to bending of the guide optical fiber that have occurred in conventional photoacoustic scanner devices, the mechanical resistance problem generated by the guide optical fiber, and the narrow scan range problem, as well as the mechanical vibration problem that has occurred when performing a linear reciprocating scan at high speed over a wide area of ​​a target in all mechanical engineering fields.

[0010] The purpose of the embodiment disclosed in the present disclosure is to provide a wide-range vibration-free linear high-speed reciprocating scanning device that can solve the mechanical vibration problem during high-speed reciprocating movement of a scanning head for a certain scanning task, thereby providing a very high level of scan uniformity over the entire target scan range.

[0011] However, the problems to be solved by the present disclosure are not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the description below.

[0012] The photoacoustic scanner according to the present disclosure is capable of acquiring high-quality images with guaranteed uniformity of signal detection at high speed over an arbitrary scan area without any mechanical vibration generation problem, and will be described with reference to an embodiment equipped with elements necessary for photoacoustic imaging.

[0013] In order to achieve the above-described technical task, the photoacoustic scanner according to the present disclosure may include a collimator that is connectable to an optical fiber that transmits light from a light source and generates parallel light; a scanning head that scans a tissue to be examined based on the parallel light generated by the collimator; and a linear actuator that is connected to the scanning head and controls a reciprocating movement of the scanning head.

[0014] In addition, the scanning head may include a prism that receives parallel light from the collimator and changes the path of the parallel light; an illumination optical unit that receives parallel light from the prism and illuminates the tissue to be examined according to a predetermined illumination pattern to induce a photoacoustic signal; an ultrasonic transducer that detects the photoacoustic wave induced by the illumination optical unit; and a scanning head frame that fixes the prism, the illumination optical unit, and the ultrasonic transducer.

[0015] Additionally, the linear actuator may be connected to the scanning head frame.

[0016] In addition, the linear actuator may include a fixed part; and a movable part that reciprocates along the X-axis direction by a driving force provided from the fixed part and is connected to the scanning head.

[0017] Additionally, it may further include a base frame for fixing the linear actuator and the collimator.

[0018] Additionally, the device may further include a stage disposed at the bottom of the base frame and moving the base frame along the Y-axis direction.

[0019] In addition, the stage may include a support plate; and a moving plate attached to the base frame, which moves along the +Y-axis direction and the -Y-axis direction by a driving force provided from the support plate.

[0020] In addition, the optical fiber, the collimator, and the light source are each provided in plurality, the plurality of light sources provide lights of different wavelengths, the plurality of optical fibers are respectively connected to the plurality of light sources, and the plurality of collimators can receive the plurality of lights from the plurality of light sources through the plurality of optical fibers to generate a plurality of parallel lights.

[0021] In addition, the apparatus may further include a reflective mirror that changes the path of parallel light from one of the plurality of collimators; and a beam combiner that combines parallel light from one of the collimators and parallel light from another collimator and provides the combined light to the scanning head.

[0022] Additionally, the plurality of collimators may include a first collimator generating a first parallel light and a second collimator generating a second parallel light.

[0023] In addition, the method may further include a reflecting mirror that changes the path of the second parallel light from the second collimator; and a beam combiner that combines the first parallel light from the first collimator and the second parallel light from the second collimator and provides the combined light to the scanning head.

[0024] In addition, the linear actuator may further include a first support connected to the movable part of the linear actuator; and a second support connected to the first support and the scanning head, wherein the first support may be further connected to the scanning head frame, and the second support may be further connected to the illumination optical part. In addition, the first support and the second support may extend in directions intersecting each other, and the first support may extend along the Z-axis direction, and the second support may extend along the X-axis direction. In addition, the first support and the second support may be formed integrally.

[0025] Additionally, the linear actuator may further include a housing in which the collimator and the linear actuator are arranged, and the collimator and the linear actuator may be attached to the housing.

[0026] Additionally, the lighting optical section includes one convex lens, and the ultrasonic transducer can be placed at a central lower point of the one convex lens.

[0027] In addition, the scanning head includes a flat mirror that receives parallel light from the collimator and changes the path of the parallel light; an illumination optical unit that receives parallel light from the flat mirror and illuminates the tissue to be examined according to a predetermined illumination pattern to induce a photoacoustic signal; an ultrasonic transducer that detects the photoacoustic wave induced by the illumination optical unit; and a scanning head frame that fixes the flat mirror, the illumination optical unit, and the ultrasonic transducer, wherein the illumination optical unit includes one convex lens, and the ultrasonic transducer can be placed at a point below the center of the one convex lens.

[0028] Additionally, the ultrasonic transducer may be placed inside the illumination optical unit.

[0029] Additionally, the lighting optical unit may be placed inside the ultrasonic transducer.

[0030] Additionally, the ultrasonic transducer may be a ring transducer having a ring-shaped opening.

[0031] A wide-range vibration-free linear reciprocating scanning device for transporting a scanning head according to the present disclosure comprises: a first bevel gear rotated by a driving motor; a crank coupled to the first bevel gear and converting a rotational motion of the first bevel gear into a linear motion in conjunction with a first link and a second link; a first link and a second link connected to the crank and linearly moving according to the linear motion converted from the crank; and a first slider and a second slider respectively connected to the first link and the second link and linearly moving according to the linear motion of the first link and the second link, wherein the scanning head is connected to the first slider and linearly moves according to the linear motion of the first slider.

[0032] In addition, the crank may include a central shaft coupled to the first bevel gear; two first connecting arms respectively connected to both sides of the central shaft; two first shafts respectively connected to the two first connecting arms and to which the first link is rotatably coupled; two second connecting arms respectively connected to the two first shafts; and two second shafts respectively connected to the two second connecting arms and to which the second link is rotatably coupled.

[0033] In addition, the central shaft may be connected to the center of the first connecting arm, the second connecting arm may be arranged symmetrically to the first connecting arm, the center of rotation of the first connecting arm may be the center of the first connecting arm, and the center of rotation of the second connecting arm may be the center of the second connecting arm.

[0034] Additionally, the length of the L section from the rotation center of the first connecting arm and the second connecting arm to each end may be the same as the length of the R section from the rotation center of the first connecting arm and the second connecting arm to each other end.

[0035] Additionally, the first slider and the second slider may include a first linear stage and a second linear stage, respectively, which are coupled to enable linear movement.

[0036] Additionally, the second slider may further include an offset mass detachably coupled to the second slider.

[0037] Additionally, the mass of the offset mass can be set so that the total mass of all transport elements in the direction in which the scanning head is located and the total mass of all transport elements in the other direction are equal to each other.

[0038] According to the above-described problem solving means of the present disclosure, it provides the effect of solving all of the following problems: the problem of non-uniformity of light transmission due to bending of the guide optical fiber, the problem of mechanical resistance generated by the guide optical fiber, the problem of narrow scan range that may occur in the existing method, and the problem of mechanical vibration regardless of the scan range (stroke) during high-speed scanning.

[0039] In addition, according to the above-described problem solving means of the present disclosure, when the mechanical scanner structure of the present disclosure is applied to a photoacoustic imaging device, a laser beam of very uniform intensity can be delivered to the tissue to be examined regardless of the scan range and speed, thereby improving the reliability of the provided photoacoustic image, and providing the effect of removing at once the elastic resistance generated by the optical fiber in the existing scan structure, thereby providing the effect of enabling faster image scanning over a much wider area than before.

[0040] In addition, the increased uniformity of the amount of light by the photoacoustic scanner structure of the present disclosure provides an effect of significantly increasing the reliability of quantitative imaging, which has recently become important in the relevant field, such as improving the quantitative reliability of photoacoustic images to be provided in a functional photoacoustic imaging process requiring spectroscopic imaging, such as dual-wavelength imaging.

[0041] The effects of the present disclosure are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description below.

[0042] Figure 1 is a schematic diagram of an optoacoustic scanner according to one embodiment of the present invention.

[0043] Figure 2 is a drawing for explaining the operation of the photoacoustic scanner of Figure 1.

[0044] Figure 3 is a schematic diagram of an optoacoustic scanner according to another embodiment of the present invention.

[0045] Figure 4 is a schematic diagram of an optoacoustic scanner according to another embodiment of the present invention.

[0046] Figure 5 is a schematic diagram of a scanning head according to one embodiment of the present invention.

[0047] Figure 6 is a schematic diagram of a scanning head according to another embodiment of the present invention.

[0048] Figure 7 is a schematic diagram of a scanning head according to another embodiment of the present invention.

[0049] Figure 8 is a schematic diagram of an optoacoustic scanner according to another embodiment of the present invention.

[0050] Figure 9 is a drawing of the photoacoustic scanner of Figure 8 viewed from above.

[0051] Fig. 10 is a drawing for explaining the movement direction of the scanning head and offset mass of the photoacoustic scanner of Fig. 8.

[0052] FIG. 11 is a schematic diagram showing an example of how a counterweight can be mounted to minimize the total weight of an optoacoustic scanner according to another embodiment of the present invention.

[0053] FIG. 12 is a schematic diagram showing a situation in which an encoder capable of measuring the exact translational movement value of a scanning head is mounted during a high-speed scanning process of an optical acoustic scanner according to another embodiment of the present invention.

[0054] FIG. 13 is a schematic diagram showing the structure of a wide-range vibration-free linear high-speed reciprocating scanning device that can completely eliminate the problem of mechanical vibration generation during wide-range reciprocating high-speed scanning according to one embodiment of the present invention.

[0055] Fig. 14 is a perspective view to more clearly show the shape of the crank applied to Fig. 13.

[0056] Fig. 15 is a schematic diagram showing the structure and shape of the first link and the second link applied to Figs. 8 to 13.

[0057] Fig. 16 is a schematic diagram for explaining the operating principle of the embodiment presented in Fig. 13.

[0058] Throughout this disclosure, the same reference numerals denote the same components. This disclosure does not describe all elements of the embodiments, and any content that is common in the technical field to which this disclosure pertains or that overlaps between embodiments is omitted. The terms "part, module, element, block" used in the specification may be implemented in software or hardware, and depending on the embodiments, multiple "parts, modules, elements, blocks" may be implemented as a single component, or a single "part, module, element, block" may include multiple components.

[0059] Throughout the specification, when a part is said to be "connected" to another part, this includes not only direct connection but also indirect connection, and indirect connection includes connection via a wireless communication network.

[0060] Additionally, when a part is said to "include" a component, this does not mean that it excludes other components, but rather that it may include other components, unless otherwise specifically stated.

[0061] Throughout the specification, when we say that an element is "on" another element, this includes not only cases where the element is in contact with the other element, but also cases where another element exists between the two elements.

[0062] The terms first, second, etc. are used to distinguish one component from another, and the components are not limited by the aforementioned terms.

[0063] Singular expressions include plural expressions unless the context clearly indicates otherwise.

[0064] The identification codes for each step are used for convenience of explanation and do not describe the order of each step. Each step may be performed in a different order than specified unless the context clearly indicates a specific order.

[0065] The operating principle and embodiments of the present disclosure are described below with reference to the attached drawings.

[0066] Figure 1 is a schematic diagram of an optoacoustic scanner according to one embodiment of the present invention.

[0067] An optoacoustic scanner according to one embodiment may include a collimator (200), a scanning head (300), a linear actuator (400), a base frame (500), and a stage (600), as shown in the example in FIG. 1. Here, the scanning head (300) may include a prism (310), an illumination optics (330), an ultrasonic transducer (340), and a scanning head frame (320).

[0068] Hereinafter, the aforementioned components are described in detail as follows.

[0069] The collimator (200) has a structure that can be attached (detachable) to the guide optical fiber (100), and can receive a laser beam from a light source (not shown) through the guide optical fiber (100), convert the received light into parallel light, and emit it. For example, the collimator (200) can receive a laser beam from a light source through the guide optical fiber (100), generate parallel light, and provide the generated parallel light to the prism (310) of the scanning head (300). In other words, the collimator (200) can perform a role of emitting (or oscillating) the light provided from the light source through the guide optical fiber (100) to the prism (310) in the form of accurate parallel light. In one embodiment, the light source may be a pulsed light source used for photoacoustic imaging.

[0070] The prism (310) can change the direction of parallel light emitted from the collimator (200). For example, the prism (310) can change the path of parallel light emitted from the collimator (200) so that the parallel light from the collimator (200) can be incident on the scanning head (300). According to one embodiment, light (e.g., parallel light) emitted from the collimator (200) along the +X-axis direction is incident on the prism (310) in the +X-axis direction, and light incident on the prism (310) in the +X-axis direction is turned 90° with respect to the +X-axis direction and can be incident in the +Z-axis direction.

[0071] The illumination optical unit (330) may perform the function of inducing a photoacoustic signal by illuminating the test tissue (10) with light according to a predetermined illumination pattern. To this end, according to one embodiment, the illumination optical unit (330) may include at least one (e.g., single or multiple) lens.

[0072] The ultrasonic transducer (340) can detect photoacoustic waves induced by the illumination optical unit (330).

[0073] The scanning head frame (320) can fix the aforementioned prism (310), the illumination optical unit (330), and the ultrasonic transducer (340). For example, the scanning head frame (320) can serve as a frame that integrally fixes the aforementioned prism (310), the illumination optical unit (330), and the ultrasonic transducer (340).

[0074] The linear actuator (400) is connected to the scanning head (300) to provide precise linear motion conditions to the scanning head (300) and also to control its reciprocating motion. For example, the linear actuator (400) can generate a linear reciprocating motion along the +X-axis direction and the opposite direction of the +X-axis direction (hereinafter, the -X-axis direction). The linear actuator (400) can provide the power required for the linear reciprocating motion to the aforementioned scanning head (300). For this purpose, according to one embodiment, the linear actuator (400) can be connected to the scanning head (300). For example, the linear actuator (400) can be attached to the outer surface of the scanning head (300). According to one embodiment, the linear actuator (400) can include a fixed part (400-1) and a movable part (400-2; for example, an arm). A driving motor (not shown) may be placed inside the fixed part (400-1), and the power of the driving motor may be transmitted to the movable part (400-2). The movable part (400-2) may perform a linear reciprocating motion in the +X-axis direction and the -X-axis direction according to the driving force provided from the driving motor. The movable part (400-2) of the linear actuator (400) may be attached to the scanning head (300) described above. When the movable part (400-2) of the linear actuator (400) moves (e.g., extends) along the +X-axis direction, the scanning head (300) attached to the movable part (400-2) may move along the +X-axis direction. For example, when the movable part (400-2) of the linear actuator (400) extends in the +X-axis direction, all components of the scanning head (300) (e.g., the prism (310), the scanning head frame (320), the illumination optical part (330), and the ultrasonic transducer (340)) can move together along the +X-axis direction. Meanwhile, when the movable part (400-2) of the linear actuator (400) moves (e.g., contracts) along the -X-axis direction, the scanning head (300) attached to the movable part (400-2) can move along the -X-axis direction.For example, when the movable part (400-2) of the linear actuator (400) contracts in the -X-axis direction, all components of the scanning head (300) (e.g., the prism (310), the scanning head frame (320), the illumination optical part (330), and the ultrasonic transducer (340)) can move together along the -X-axis direction.

[0075] The base frame (500) can fix the collimator (200) and the linear actuator (400) to each other. For example, the collimator (200) can be placed on the upper surface of the base frame (500), and in this case, the collimator (200) can be attached to and fixed to the upper surface of the base frame (500). In addition, the linear actuator (400) can be inserted into and fixed to the inside of the base frame (500). For example, the fixing part (400-1) of the linear actuator (400) can be inserted into the inside of the base frame (500) and fixed to the base frame (500). Accordingly, the collimator (200) and the linear actuator (400) can be fixed to the base frame (500). At this time, the fixed part (400-1) of the linear actuator (400) may be attached and fixed to the base frame (500), while the movable part (400-2) of the linear actuator (400) may be attached and fixed to the scanning head (300) described above. For example, one end of the movable part (400-2) may be attached and fixed to the outer surface of the scanning head (300).

[0076] The stage (600) may be disposed below the base frame (500) described above. Accordingly, the base frame (500) may be disposed between the collimator (200) and the stage (600). In addition, the linear actuator (400) may also be disposed between the collimator (200) and the stage (600). The stage (600) may be attached and fixed to the base frame (500) described above. The stage (600) may perform a linear reciprocating motion along a direction intersecting the direction of movement of the linear actuator (400) described above (e.g., the +X-axis direction and / or the -X-axis direction). For example, the stage (600) may move along the +Y-axis direction and the opposite direction of the +Y-axis direction (hereinafter, the -Y-axis direction). According to one embodiment, the stage (600) may be a motorized y-stage. To this end, a stage (600) according to one embodiment may include a support plate (600-1) and a moving plate (600-2). The moving plate (600-2) may be placed on the support plate (600-1). The moving plate (600-2) may be driven by a drive motor inside the support plate (600-1) and may move along the +Y-axis direction and the -Y-axis direction described above. The moving plate (600-2) of the stage (600) described above may be attached to the lower surface of the base frame (500) described above. As the stage (600) moves along the +Y-axis direction and the -Y-axis direction, the base frame (500) connected to the stage (600) can move along the +Y-axis direction and the -Y-axis direction, and as the base frame (500) moves along the +Y-axis direction and the -Y-axis direction, the linear actuator (400) and collimator (200) connected to the base frame (500) can move along the +Y-axis direction and the -Y-axis direction, and as the linear actuator (400) moves along the +Y-axis direction and the -Y-axis direction, the scanning head (300) connected to the movable part (400-2) of the linear actuator (400) can move along the +Y-axis direction and the -Y-axis direction.

[0077] In this way, the scanning head (300) can be moved (or transferred) along the +X-axis direction and the -X-axis direction according to the movement of the linear actuator (400) in the +X-axis direction and the -X-axis direction, and the scanning head (300) can be moved (or transferred) along the +Y-axis direction and the -Y-axis direction according to the movement of the stage (600) in the +Y-axis direction and the -Y-axis direction. In other words, the scanning head (300) can be moved (or transferred) in the +X-axis direction and the -X-axis direction and in the +Y-axis direction and the -Y-axis direction by the linear actuator (400) and the stage (600).

[0078] Finally, according to the photoacoustic scanner of one embodiment, a two-dimensional photoacoustic image (e.g., a B-scan image) on the XZ plane can be acquired by moving the scanning head (300) in the +X-axis direction and the -X-axis direction by the reciprocating linear motion provided by the linear actuator (400), and a final three-dimensional volume image of the tissue to be examined (10) can be acquired through the scanning motion in the +Y-axis direction and the -Y-axis direction additionally provided by the stage (600). Of course, in the case of another embodiment, the stage (600) disclosed above does not necessarily need to be a stage that provides only linear motion along the +Y-axis direction and the -Y-axis direction, and may be replaced with a device that provides a curved motion such as an arc, such as a goniometer, or a rotational motion, such as a rotational stage. Of course, when this element is applied, the three-dimensional image provided accordingly has a cylindrical shape.

[0079] FIG. 2 is a diagram for explaining the operation of the photoacoustic scanner of FIG. 1. For example, FIG. 2 is a schematic diagram showing how the position of the scanning head (300) of the photoacoustic scanner of FIG. 1 changes during a reciprocating scan along the +X-axis direction and the -X-axis direction according to the operating principle of the photoacoustic scanner of the embodiment described above.

[0080] Referring to FIG. 2, the linear actuator (400) may include a fixed part (400-1) fixed to a base frame (500) and a movable part (400-2) having one end attached to a scanning head (300) and performing reciprocating motion (e.g., reciprocating motion in the +X-axis direction and the -X-axis direction), and the movement range (e.g., stroke) of the linear actuator (400) may determine a physically actual scannable range. For example, the movement range of the movable part (400-2) provided in the linear actuator (400) in the +X-axis direction and the -X-axis direction may define the scannable range of the photoacoustic scanner in the +X-axis direction and the -X-axis direction according to one embodiment.

[0081] Meanwhile, the fixed part (400-1) and the movable part (400-2) of the linear actuator (400) equipped in the photoacoustic scanner of one embodiment may be understood to correspond to, for example, the block part and the rail part equipped in the LM (Linear Motion) guide currently used in industrial sites, respectively; however, the linear actuator (400) of one embodiment is not limited thereto. For example, the fixed part (400-1) equipped in the photoacoustic scanner of one embodiment may be a device or means that includes a power supply device such as a motor.

[0082] As in the example illustrated in FIG. 2, when the stage (600) is stationary (e.g., when the movement of the scanning head (300) in the +Y-axis direction and -Y-axis direction is stopped), the linear actuator (400) performs a reciprocating linear movement (e.g., movement in the +X-axis direction and -X-axis direction) alone, thereby obtaining a B-scan image of the tissue to be examined (10).

[0083] According to one embodiment, the linear actuator (400) includes a fixed part (400-1) and a movable part (400-2), and when the movable part (400-2) reciprocates (e.g., linear reciprocating motion in the +X-axis direction and the -X-axis direction), only the scanning head (300) moves and the collimator (200) does not move, so the guide optical fiber (100) connected to the collimator (200) does not move either. In other words, even when the collimator (200) is scanned in the +X-axis direction and the -X-axis direction for acquiring a B-scan image, the collimator (200) remains fixed, so that the guide optical fiber (100) connected to the collimator (200) can be maintained in a constant shape without being bent. Accordingly, the bending problem of the guide optical fiber (100) during the high-speed scanning process is resolved, and ultimately, in the process of obtaining a two-dimensional photoacoustic image along the XZ plane, the amount of light transmitted to the test tissue (10) becomes much more uniform, regardless of the scan range in the +X-axis direction and the -X-axis direction, and as a result, a photoacoustic image that is much more quantitatively reliable than the conventional technology can be obtained. In addition, problems such as a kind of resistance (e.g., resistance due to bending of the guide optical fiber (100)) during the reciprocating scan movement caused by the guide optical fiber (100) attached to the scanning head (300) in the conventional technology are also eliminated, and an additional effect of enabling a significantly faster high-speed scan than the conventional technology can be obtained. In the case of actual conventional technology, if the guide optical fiber (100) to be applied to the device is a multi-mode type rather than a single mode and has a thickness of 200 μm or more, the problem of resistance generation due to bending of the guide optical fiber (100) has become a serious problem that cannot be ignored.

[0084] Meanwhile, in order for the scanning operation according to the principle of the above-described embodiment to be effectively performed, the collimator (200) must be able to create very accurate parallel light, and also, accurate optical axis alignment for the laser beam incident from the collimator (200) to the scanning head (300) must be guaranteed. However, in the field of optical fiber-related technology, a precision collimator (200) for optical fibers based on an aspherical lens is already commercially available, and the current related mechanical frame processing and assembly technology is at a level where there is no problem in realizing accurate axis alignment between the collimator (200) and the scanning head (300), so a photoacoustic scanner capable of performing the scanning operation according to the principle of the above-described embodiment is a device that is sufficiently feasible (or feasible) at the present stage.

[0085] Of course, even if a photoacoustic scanner is implemented according to one embodiment, it is true that the signal transmission wire (not shown) that should normally be attached to the ultrasonic transducer (340) is not completely removed, but such a signal transmission wire is not a factor that affects the non-uniformity problem of the photoacoustic image raised in one embodiment, and since there is no problem even if the thickness of the signal transmission wire required for the related device is 200 μm or less, the problem of the wire bending during reciprocating motion is not a problem at all.

[0086] An embodiment of a photoacoustic scanner utilizing a single-wavelength laser beam has been presented. However, the concept of a photoacoustic scanner disclosed in the disclosure according to one embodiment can be readily extended and implemented using two or more wavelengths. A photoacoustic scanner according to one embodiment is described in detail below with reference to FIG. 3.

[0087] Figure 3 is a schematic diagram of an optoacoustic scanner according to another embodiment of the present invention.

[0088] According to one embodiment, an optoacoustic scanner may include a first collimator (200-1), a second collimator (200-2), a reflective mirror (700), a beam combiner (800), a scanning head (300), a linear actuator (400), and a base frame (500), as shown in the example in FIG. 3. Here, the scanning head (300) may include a prism (310), an illumination optical unit (330), an ultrasonic transducer (340), and a scanning head frame (320).

[0089] The first collimator (200-1) can receive a first laser beam (e.g., a first laser beam having a first wavelength (λ1)) from a first light source (not shown) through a first guide optical fiber (100-1), convert the received light into parallel light, and emit the parallel light. For example, the first collimator (200-1) can receive a first laser beam from the first light source through the first guide optical fiber (100-1), generate parallel light (hereinafter, referred to as first parallel light), and transmit the generated first parallel light to a beam combiner (800). In one embodiment, the first light source may be a pulsed light source used for photoacoustic imaging.

[0090] The second collimator (200-2) may be arranged adjacent to the first collimator (200-1). For example, the second collimator (200-2) may be arranged adjacent to the first collimator (200-1) in the -Y-axis direction. In addition, the second collimator (200-2) and the first collimator (200-1) may be arranged parallel to each other (or in parallel) along the X-axis direction. The second collimator (200-2) may receive a second laser beam (e.g., a second laser beam having a second wavelength (λ2)) from a second light source (not shown) through the second guide optical fiber (100-2), and may convert the received light into parallel light and emit it. For example, the second collimator (200-2) may receive a second laser beam from a second light source through a second guide optical fiber (100-2), generate parallel light (hereinafter, referred to as second parallel light), and transmit the generated second parallel light to a reflection mirror (700). In one embodiment, the second light source may be a pulsed light source used for photoacoustic imaging. The first wavelength (λ1) described above is a fundamental wavelength, and the second wavelength (λ2) is an additional wavelength, and the first wavelength (λ1) and the second wavelength (λ2) may have different values.

[0091] The reflecting mirror (700) can reflect the second parallel light incident from the second collimator (200-2) and provide it to the aforementioned beam combiner (800). In other words, the second parallel light from the second collimator (200-2) can have its path changed by the reflecting mirror (700) and be incident on the beam combiner (800).

[0092] The beam combiner (800) can combine the first parallel light from the first collimator (200-1) and the second parallel light from the second collimator (200-2). For example, the first parallel light from the first collimator (200-1) and the second parallel light from the second collimator (200-2) can be precisely overlapped by the beam combiner (800). The parallel lights overlapped by the beam combiner (800) can be incident on the prism (310) of the scanning head (300) in the form of precisely parallel lights.

[0093] The configuration and operation of the scanning head (300) of FIG. 3 are the same as the configuration and operation of the scanning head (300) of FIG. 1 described above, so the description of the scanning head (300) of FIG. 3 refers to the scanning head (300) of FIG. 1 described above and related contents.

[0094] In the embodiment of FIG. 3 as well, the key is to perfectly align the parallel lights emitted from the two collimators, i.e., the first collimator (200-1) and the second collimator (200-2), so that they exactly overlap each other using the beam combiner (800) and are accurately incident on the prism (310) mounted on the scanning head (300). In order to make the laser beam of the additional wavelength (λ2) emitted from the second collimator (200-2) into perfectly parallel light, an accurate aspherical lens suitable for the corresponding wavelength must be applied. Of course, in FIG. 3, the second guide optical fiber (100-2) can play a role in transmitting the second laser beam of the additional laser wavelength (λ2) from the corresponding light source (e.g., the second light source) to the second collimator (200-2).

[0095] Meanwhile, the photoacoustic scanner of FIG. 3 may not include the stage (600) illustrated in FIG. 1. However, alternatively, the photoacoustic scanner of FIG. 3 may further include the aforementioned stage (600; e.g., a motorized y-stage). For example, the aforementioned stage (600) may be further attached to the lower portion of the base frame (500) of FIG. 3.

[0096] Here, with reference to FIG. 3, an embodiment of a photoacoustic scanner in which two different wavelength laser beams are applied has been described. However, the described wavelength addition principle can be extended to not only two wavelengths but also three or more, and can even be expanded and applied to simultaneously integrating an acoustic-resolution photoacoustic imaging mode that primarily applies a weakly focused laser beam into a single device. Here, the latter case (e.g., an embodiment that simultaneously integrates an acoustic-resolution photoacoustic imaging mode that primarily applies a weakly focused laser beam into a single device) refers to a case in which an optical-resolution photoacoustic imaging mode and an acoustic-resolution photoacoustic imaging mode are integrated into a single device. Of course, when adding an acoustic-resolution photoacoustic imaging mode, it is theoretically impossible to precisely parallelize the light emitted from the multimode optical fiber that should normally be applied thereto. However, due to the nature of the acoustic-resolution photoacoustic imaging mode, such slight non-parallelism is not a major problem.

[0097] Figure 4 is a schematic diagram of an optoacoustic scanner according to another embodiment of the present invention.

[0098] An optoacoustic scanner according to one embodiment may include a case (1000), a collimator (200), a scanning head (300), a linear actuator (400), and a housing (500'), as shown in the example in FIG. 4. Here, the scanning head (300) may include a prism (310), an illumination optical unit (330), an ultrasonic transducer (340), and a scanning head frame (320).

[0099] The case (1000) can surround the collimator (200), scanning head (300), linear actuator (400), and housing (500') described above. Of course, the case (1000) can include a handle-shaped portion.

[0100] The collimator (200) and the linear actuator (400) may be placed inside the housing (500'). At this time, the collimator (200) and the linear actuator (400) may be fixed to the housing (500') within the housing (500'). For example, the collimator (200) and the linear actuator (400) may be attached and fixed to the inner wall of the interior of the housing (500'). Here, the linear actuator (400) may include a fixed part (400-1) and a movable part (400-2) as described above, and the fixed part (400-1) of the linear actuator (400) may be attached to the inner wall of the housing (500').

[0101] The first support member (901) may be disposed inside the scanning head frame (320). The first support member (901) may be connected to the movable member (400-2) of the linear actuator (400). For example, one end of the first support member (901) may be coupled to one end of the movable member (400-2). The first support member (901) may extend in a direction (e.g., the Z-axis direction) that intersects the extension direction of the movable member (400-2) (e.g., the X-axis direction). In addition, the first support member (901) may be attached and fixed to an inner wall of the scanning head frame (320) within the scanning head frame (320). For example, the first support member (901) may be fixed to the inner wall of the scanning head frame (320).

[0102] The second support (902) may be arranged inside the scanning head frame (320). The second support (902) may be connected to the first support (901). For example, one end of the second support (902) may be coupled to the other end of the first support (901). Meanwhile, the second support (902) and the first support (901) may be formed integrally. The first support (901) and the second support (902) formed integrally may have an L-shaped cross-section. The second support (902) may extend in a direction (e.g., the X-axis direction) intersecting the extension direction (e.g., the Z-axis direction) of the first support (901). The second support (902) may surround the illumination optical unit (330). To this end, according to one embodiment, the second support member (902) may have a hole through which the illumination optical member (330) is inserted. The illumination optical member (330) may pass through the hole of the second support member (902) and be surrounded by the hole. In this case, the illumination optical member (330) may be attached to and fixed to the inner wall of the hole of the second support member (902).

[0103] When the movable part (400-2) of the linear actuator (400) moves (e.g., extends) along the X-axis direction, the first support part (901) and the second support part (902) attached to the movable part (400-2) can move along the X-axis direction. In addition, as the first support part (901) and the second support part (902) move along the X-axis direction, the scanning head (300) attached to the first support part (901) and the second support part (902) can move along the X-axis direction.

[0104] For example, when the movable part (400-2) of the linear actuator (400) extends in the +X-axis direction, all components of the scanning head (300) (e.g., the prism (310), the scanning head frame (320), the illumination optical part (330), and the ultrasonic transducer (340)) can move together along the X-axis direction. Meanwhile, when the movable part (400-2) of the linear actuator (400) moves (e.g., contracts) along the -X-axis direction, the first support part (901) and the second support part (902) attached to the movable part (400-2) can move along the -X-axis direction. In addition, as the first support (901) and the second support (902) move along the -X-axis direction, the scanning head (300) attached to the first support (901) and the second support (902) can move along the -X-axis direction. For example, when the movable part (400-2) of the linear actuator (400) contracts in the -X-axis direction, all components of the scanning head (300) (e.g., the prism (310), the scanning head frame (320), the illumination optics (330), and the ultrasonic transducer (340)) can move together along the -X-axis direction.

[0105] Meanwhile, the photoacoustic scanner of FIG. 4 may further include a stage (600; for example, a motorized y-stage) as shown in FIG. 2 attached to a housing (500'). When the stage (600) moves along the +Y-axis direction and the -Y-axis direction, the housing (500') attached to the stage (600) may move along the +Y-axis direction and the -Y-axis direction. In addition, when the housing (500') moves along the +Y-axis direction and the -Y-axis direction, the collimator (200) and the linear actuator (400) inside the housing (500') may move together along the +Y-axis direction and the -Y-axis direction. In addition, when the linear actuator (400) moves along the +Y-axis direction and the -Y-axis direction, the first support (901) and the second support (902) connected to the movable part (400-2) of the linear actuator (400) can move together along the +Y-axis direction and the -Y-axis direction. In addition, when the first support (901) and the second support (902) move along the +Y-axis direction and the -Y-axis direction, the scanning head (300) connected to the first support (901) and the second support (902) can move together along the +Y-axis direction and the -Y-axis direction. Additionally, when the scanning head (300) moves along the +Y-axis direction and the -Y-axis direction, the prism (310), the illumination optical unit (330), the ultrasonic transducer (340), and the scanning head frame (320) of the scanning head (300) can move together along the +Y-axis direction and the -Y-axis direction.

[0106] Meanwhile, the structure of the scanning head (300) illustrated in FIG. 1 can be implemented by modifying it into any number of other forms, as illustrated in FIGS. 5 to 7. Hereinafter, various possible modifications of the scanning head (300) will be described in detail with reference to FIGS. 5 to 7.

[0107] FIG. 5 is a schematic diagram of a scanning head (300) according to one embodiment of the present invention, FIG. 6 is a schematic diagram of a scanning head (300) according to another embodiment of the present invention, and FIG. 7 is a schematic diagram of a scanning head (300) according to another embodiment of the present invention.

[0108] For example, as illustrated in FIG. 5, the illumination optical unit (330) may be implemented in a very simple form by applying a single convex lens (330-1) that performs a light convergence function, and in this case, it is preferable to position the ultrasonic transducer (340) at a point below the center of the single convex lens (330-1). Here, the ultrasonic transducer (340) is a component provided to detect a photoacoustic wave induced by a laser pulse transmitted to the tissue to be examined (10). In the case of the optical resolution photoacoustic imaging mode, since the lateral resolution is usually determined by the beam diameter of the laser beam at the focus, the diameter may be less than 1 mm, and this can be a level that does not greatly interfere with the laser beam traveling around it. Even when applying the acoustic resolution photoacoustic imaging mode that does not focus the laser beam transmitted to the test tissue (10), the diameter of the ultrasonic transducer (340) to be applied does not necessarily have to be larger than 1 mm because the desired image can be generated by applying the reconstruction principle. The dimension setting principles related to the diameter of the ultrasonic transducer (340) and the diameter of the laser beam passing around it are already self-evident in the relevant field and are therefore omitted.

[0109] In the case of the prism (310) that converts the parallel light emitted from the collimator (200) by 90° and provides it to the illumination optical unit (330), it can be implemented by applying a simple flat mirror (310-1) as shown in FIG. 6, and the positions of the illumination optical unit (330) and the ultrasonic transducer (340) can also be exchanged, as shown in FIG. 7. Here, the green lens (330-2) shown in FIG. 7 has a cylindrical shape, but has a characteristic in which the refractive index inside it decreases as it gets farther away from the central axis, so that when the parallel light enters the incident surface, it converges as it passes through the inside. In this case, when it is desired to use the green lens (330-2) as an illumination optical part (330), the ultrasonic transducer (340) that detects the photoacoustic wave may be replaced with a ring transducer (340-1) having a ring-shaped aperture as shown in FIG. 7.

[0110] According to one embodiment, the scanning head (300) of FIG. 1 may be replaced with any one of the scanning heads (300) of FIGS. 5 to 7. Similarly, the scanning head (300) of FIG. 3 may be replaced with any one of the scanning heads (300) of FIGS. 5 to 7. Similarly, the scanning head (300) of FIG. 4 may be replaced with any one of the scanning heads (300) of FIGS. 5 to 7.

[0111] According to the photoacoustic scanner of the above embodiment, the problem of uneven light transmission due to the bending of the guide optical fiber (100) directly connected to the scanning head (300) during mechanical scanning, which has long been a bothersome problem in the prior art, the problem of mechanical resistance generated by the guide optical fiber (100), and the problem of narrow scanning range in the prior art can all be solved.

[0112] According to one embodiment, the improved uniformity of the amount of light can be of great help in improving the quantitative reliability of the photoacoustic image to be provided in the functional photoacoustic imaging process that requires spectral images, such as dual-wavelength, and further, it is obvious that the scanning concept presented according to one embodiment can be implemented in the form of a handheld probe, that is, a handle type that allows a user to directly hold the device by hand and freely image a desired area of ​​the surface of a living body to be examined, such as a human or an animal, and further, it can be implemented in a wide variety of forms, such as a miniature probe that photographs the inside of a living body close to the body surface in an invasive or non-invasive manner accompanied by surgery, and even an endoscopic device that images the deep parts of a living body.

[0113] Hereinafter, with reference to FIGS. 8 to 11, the present photoacoustic scanner having an original structure capable of eliminating mechanical vibration that may occur during a high-speed scanning process by offsetting the total momentum vector of all moving elements of the device to zero (0) even when the scanning head (300) moves back and forth will be described in detail.

[0114] FIG. 8 is a schematic diagram of an optoacoustic scanner according to another embodiment of the present invention, and FIG. 9 is a view of the optoacoustic scanner of FIG. 8 as viewed from above.

[0115] According to one embodiment, an optoacoustic scanner may include a collimator (200), a driving motor (555), a frame (505), a scanning head (300), a symmetrical actuator, and a counterbalance mass (777) so that the total momentum of the scanning head (300) and the transport part is counterbalanced to zero during the scanning process, as shown in FIGS. 8 and 9.

[0116] The collimator (200) can receive a laser beam from a light source through a guided optical fiber to generate parallel light and provide the generated parallel light to the prism of the scanning head (300).

[0117] The drive motor (555) is a device that generates rotational power, and a drive motor reducer (555a) may be added to increase its torque.

[0118] A symmetrical actuator can be placed on the frame (505).

[0119] The above symmetrical actuator can move the scanning head (300) and the offset mass (777) in opposite directions. As shown in FIGS. 8 to 10, the above symmetrical actuator can include a driving device (110), a first rotating part (120a), a first link (130a), a first slider (140a), a first linear stage (150a), a second rotating part (120b), a second link (130b), a second slider (140b), and a second linear stage (150b).

[0120] The driving device (110) is a device that receives rotational power from the driving motor reducer (555a) and distributes and transmits the rotational power to subsequent elements to be described later, and may include a first bevel gear (110a) and a second bevel gear (110b) therein. Of course, unlike the above, the driving device (110) may be implemented as a device that includes a first bevel gear (110a) connected to a first rotating part (120a) and a second bevel gear (110b) connected to a second rotating part (120b). A center gear (555b) is rotatably connected to the rotational shaft of the driving motor reducer (555a), and thus the first bevel gear (110a) and the second bevel gear (110b) of the driving device (110) may be coupled to the center gear (555b). Accordingly, when the rotation axis of the drive motor reducer (555a) rotates, the center gear (555b) rotates, and the first bevel gear (110a) and the second bevel gear (110b) meshed with the center gear (555b) rotate in opposite directions at the same angular velocity.

[0121] A first rotating part (120a) can be connected to the first bevel gear (110a) of the driving device (110).

[0122] The first rotating part (120a) can be connected to the first link (130a).

[0123] The first link (130a) may be connected to the first slider (140a). For example, one side of the first link (130a) may be rotatably connected to the first rotating part (120a), and the other side of the first link (130a) may be connected to the first slider (140a).

[0124] Therefore, when the first bevel gear (110a) and the first rotary part (120a) rotate, the first link (130a) connected thereto rotates and translates, and the first slider (140a) can move in a linear direction by the translational motion component of the first link (130a). At this time, the first slider (140a) can reciprocate in a linear direction together with the first linear stage guide rail (170a), which is a component of the first linear stage (150a) (see FIG. 10). Therefore, when the first bevel gear (110a) of the driving device (110) rotates, the scanning head (300) connected to the first slider (140a) can move in a linear direction.

[0125] A second rotating part (120b) can be connected to the second bevel gear (110b) of the driving device (110).

[0126] The second rotating part (120b) can be connected to the second link (130b).

[0127] The second link (130b) may be connected to the second slider (140b). For example, one side of the second link (130b) may be rotatably connected to the second rotating part (120b), and the other side of the second link (130b) may be connected to the second slider (140b).

[0128] Therefore, when the second bevel gear (110b) and the second rotary part (120b) rotate, the second link (130b) connected thereto rotates and translates, and the second slider (140b) can move in a linear direction by the translational motion component of the second link (130b). At this time, the second slider (140b) can reciprocate in a linear direction together with the second linear stage guide rail (170b), which is a component of the second linear stage (150b) (see FIG. 10). Therefore, when the second bevel gear (110b) of the driving device (110) rotates, the offset mass (777) connected to the second slider (140b) can move in a linear direction.

[0129] FIG. 10 is a drawing for explaining the movement direction of the scanning head (300) and the offset mass (777) of the photoacoustic scanner of FIG. 8.

[0130] Since the first bevel gear (110a) and the second bevel gear (110b) rotate in different directions, the first slider (140a) and the second slider (140b) can move in opposite directions. For example, when the first slider (140a) moves along the tip direction of the first arrow (AR1), the second slider (140b) can move along the tip direction of the second arrow (AR2). Accordingly, when the scanning head (300) moves along the tip direction of the first arrow (AR1), the center of gravity of all the moving elements does not move at all. In other words, as the scanning head (300) moves along the direction of the first arrow (AR1), the offset mass (777) retreats along the direction of the second arrow (AR2) which is opposite to the direction of the first arrow (AR1), so the vector sum of the momentum of all moving elements including the scanning head (300) and the offset mass (777) becomes zero (0). This zero sum of momentum can eliminate the occurrence of vibration during high-speed scanning, and thus the present invention can be applied to all devices requiring mechanical scanning. Of course, the mass of the offset mass (777) must be accurately calculated and set so that the total sum of the momentum of all moving elements becomes zero.

[0131] For reference, in the case of the external shape of the scanning head (300) illustrated in FIGS. 8 to 10, an example was presented in which the shape of the lower part was made streamlined like a ship in order to minimize fluid resistance that may occur when the scanning head (300) reciprocates while immersed in a fluid such as water.

[0132] Fig. 11 is a schematic diagram showing an example of how a counterweight can be mounted to minimize the weight of a photoacoustic scanner according to another embodiment of the present invention. That is, by applying another embodiment of the present invention presented in Fig. 11, it is possible to further reduce the mass value of the counterweight (777) that must be added to eliminate vibration generation of the scanner device, thereby minimizing the increase in the mass of the entire device.

[0133] This can be achieved by installing the second linear stage (150b) on which the offset mass (777) is mounted, not as in the embodiments shown in FIGS. 8 to 10, but as shown in FIG. 11, such that the second linear stage table portion (160b) is connected to the second slider (not shown in FIG. 11 because the offset mass itself serves as the second slider) and the second linear stage guide rail (170b) is connected to the frame (505). The reason why it is meaningful to simply install the parts upside down like this is that, as an example of the second linear stage (150b) required in the present invention, a cross roller table, which is commonly used in the current industry, is very effective, and in the case of a cross roller table, which is generally used in the industry, the weight of the table portion is much heavier than the weight of the rail portion arranged in the center thereof. That is, even with such a simple installation method, the mass value of the offset mass (777) that needs to be added, i.e., the mass increase, can be minimized. On the other hand, in the case of the first linear stage (150a) side where the scanning head (300) is connected via the first slider (140a), if the mentioned cross roller table is applied, all dynamic elements connected thereto, including the first slider (140a), can be mounted on the first linear stage guide rail (170a) instead of the first linear stage table portion (160a) to minimize their total momentum. This is because, in general, a relatively large number of elements (i.e., a large mass) are already mounted on that side (i.e., the side with the scanning head) than on the other side. Of course, in the embodiment presented in FIG. 11, it is assumed that a cross roller table having the aforementioned characteristics is applied, and it should be understood that the second slider (140b) in the shape of a tunnel simultaneously functions as the offset mass (777).

[0134] Fig. 12 is a schematic diagram showing a state in which an optical encoder capable of measuring the exact translational movement value of a scanning head during a high-speed scanning process of a photoacoustic scanner according to another embodiment of the present invention is mounted. Through Fig. 12, an embodiment of a photoacoustic scanner equipped with an encoder (180) capable of accurately measuring the translational movement value of a scanning head and providing related information (signal) when the scanning head (300) reciprocates according to the operating principle described above is described.

[0135] In other words, this encoder (180) is necessary in a situation where it is necessary to know the amount of each transfer (step) very precisely and in real time for each unit transfer occurrence during the process of moving the scanning head (300). In reality, since backlash almost always exists between any two meshed bevel gears, it is generally impossible to know accurately by installing a rotary encoder that indicates the rotation angle inside the driving motor (555).

[0136] For this reason, FIG. 12 is an example showing a case in which an encoder (180) is mounted that provides the degree of transfer at each transfer step as an electrical signal (pulse) according to an optical method, and the encoder (180) operates on the same principle as an optical linear encoder commonly used in the industry, and is composed of an encoder light source (180a) that emits light in the direction of passing through a linear scale (180c), a light sensor (180b) that detects the light passing through the linear scale (180c), and a linear scale support (180d) that fixes the linear scale (180c). Of course, in the embodiments of the present invention, only the two elements, the linear scale (180c) and the linear scale support (180d) that fixes it, are mounted on the first slider (140a) and perform linear reciprocating motion together with the first slider (140a), and the encoder light source (180a) and the light sensor (180b) are mounted on the frame (505) and do not move, so that it is more effective in terms of the total weight of the dynamic parts. The linear scale (180c) refers to one element in a conventional encoder in which a portion through which light passes and a portion that does not pass are patterned at regular intervals over a predetermined area.

[0137] Meanwhile, in FIGS. 8 to 12, the first rotating part (120a) and the second rotating part (120b) are depicted as having a disk shape, but it is self-evident that they can also be implemented in a stick shape, like a crank pedal of a bicycle.

[0138] A scanning device structure has been proposed that can significantly eliminate mechanical vibration that may occur during a high-speed scan process by preventing the total center of gravity of the first and second linear stages, which are arranged in an ideally symmetrical manner, and the moving elements on both sides mounted thereon from moving during the reciprocating linear motion. However, when the device to which the principle is applied is implemented on a large scale, such as a scale of several meters, the size and weight of the first link (130a) and the second link (130b) also increase, and in the case of the embodiments presented in FIGS. 8 to 12, a situation may arise where the vibration contribution they generate cannot be ignored. This is because the first link (130a) and the second link (130b) and the bearing pins (132) connected thereto are arranged in a rotationally symmetrical manner, i.e., on opposite sides, rather than in a mirror-symmetrical manner with respect to the driving device (110).

[0139] Hereinafter, another embodiment is provided for a linearly reciprocating mechanical part (i.e., a scanner device part) that can completely solve the vibration problem that may occur in such a situation, and the mechanical device is referred to herein as a “wide-range vibration-free linear reciprocating scanning device” (hereinafter, vibration-free linear reciprocating scanning device).

[0140] FIG. 13 is a schematic diagram showing the structure of a wide-range vibration-free linear reciprocating scanning device that can almost completely eliminate the problem of mechanical vibration generation during wide-range reciprocating high-speed scanning according to one embodiment of the present invention, FIG. 14 is a perspective view to more clearly show the shape of the crank applied to FIG. 13, FIG. 15 is a schematic diagram showing the structure and shape of the first link and the second link applied to FIGS. 8 to 13, and FIG. 16 is a schematic diagram to explain the operating principle of the embodiment presented in FIG. 13 in more detail.

[0141] Referring to FIGS. 13 to 16, a vibration-free linear reciprocating scanning device according to one embodiment of the present invention comprises a first linear stage (150a) and a second linear stage (150b) arranged on both sides along the longitudinal direction of a frame (505) with a driving device (110) as a reference point, a first slider (140a) mounted on a first linear stage guide rail (170a) of the first linear stage (150a), a second slider (140b) mounted on a second linear stage table (160b) of the second linear stage (150b), two first links (130a) connected in a mirror-symmetrical direction to the left and right of the first slider (140a), two second links (130b) connected in a mirror-symmetrical direction to the left and right of the second slider (140b), and a crank (190) connected to the other end of the two first links (130a) and the two second links (130b) to provide rotational and translational motion forces to them. It can be implemented in a manner including. That is, in this embodiment, the first rotating part (120a) and the second rotating part (120b) included in FIGS. 8 to 12 are replaced with a crank (190) having the shape and structure shown in FIG. 14, and the first bevel gear (110a) and the second bevel gear (110b) that rotate in opposite directions in the embodiments of FIGS. 8 to 12 are not both involved in this embodiment, but only one bevel gear, that is, the first bevel gear (110a), is installed on the crank (190), more specifically, on the center shaft (191). As a result, both parts of the crank (190), which take a left-right mirror-symmetrical shape based on the driving device (110), receive rotational power from the center gear (555b) through only one first bevel gear (110a), so that both sides rotate only in the same direction.

[0142] Of course, in order for the vibration-free linear reciprocating scanning device provided by the present invention to completely eliminate mechanical vibration regardless of the scan range, the shape and physical characteristics of the crank to be applied to the device are also very important.

[0143] Referring to Fig. 14, the crank (190) must have a perfectly mirror-symmetrical shape with respect to the center shaft (191) on which the first bevel gear (110a) is connected, and the length of the L section and the length of the R section must be exactly the same with respect to the center shaft (191) which is the center of rotation. In other words, the mass distribution on both sides of the center shaft (191) must be exactly the same, and for this purpose, the mass of the first shaft (193) to which the first link (130a) is connected and the mass of the second shaft (195) to which the second link (130b) is connected must be precisely set so that the mass distribution on both sides can be equally formed. The reason why this part is important is that through such implementation, even if the center shaft (191) rotates at high speed, it is fundamentally necessary to prevent the vibration component caused by the centrifugal force of the mass point from occurring with respect to the center shaft (191). Also, since the length of the L section and the length of the R section are exactly the same based on the center shaft (191), when the crank (190) rotates a certain angle, the first slider (140a) and the second slider (140b) face opposite directions and move exactly the same distance. Again, referring to FIG. 13, in the case of the embodiment of FIG. 13, as in the case of FIG. 11, the second slider (140b) in the shape of a tunnel also functions as a counterbalance mass (777). If the mass value of the counterbalance mass (777) is set precisely, the sum of the momentum of all motion elements on the first and second direction sides can always be set to be zero (0) regardless of the reciprocating motion range and the transport speed of the first slider (140a) and the second slider (140b), so that no mechanical vibration due to physical motion occurs at all. Here, two first connecting arms (192) can be connected to each of the two sides of the central shaft (191). In addition, two first shafts (193) can be connected to the two first connecting arms (192).Two first links (130a) may be rotatably coupled to each of the two first shafts (193). In addition, two second connecting arms (194) may be connected to each of the two first shafts (193). In addition, two second shafts (195) may be connected to each of the two second connecting arms (194). Two second links (130b) may be rotatably coupled to each of the two second shafts (195).

[0144] FIG. 15 is a schematic diagram showing the shape and structure of the first link (130a) and the second link (130b) applied to FIGS. 8 to 13, and has a structure in which link bearings (131) are installed at the left and right ends of the link so that the rotational and translational motion power provided by the driving device (110) can be properly transmitted to the slider (140) through the link (130).

[0145] FIG. 16 is a schematic diagram for explaining the operating principle of the embodiment presented in FIG. 13. In a situation where the length of the L section and the length of the R section of the crank (190) as well as the mass distribution for each section are exactly the same, the force required for the linear movement of the first and second sliders (140) is evenly transmitted while maintaining the left-right balance through the first link (130a) and the second link (130b) which are arranged in a mirror-symmetrical form on the left and right sides based on the long axis direction of the frame (505). Therefore, if only the mass of the upper mass (777) is accurately calculated and installed, the mechanical vibration and centrifugal force caused by the mass points that are somewhat asymmetrically distributed as in the embodiments of FIGS. 8 to 10 can theoretically be almost completely eliminated.

[0146] A vibration-free linear reciprocating scanning device for transporting a scanning head according to one embodiment of the present invention includes a first bevel gear (110a) that is rotated by a driving motor (555), a crank (190) that is coupled to the first bevel gear (110a) and transmits the rotational motion of the first bevel gear (110a) to the first link (130a) and the second link (130b), a first link (130a) and a second link (130b) that are connected to the crank (190) and receive power from the crank (190) to perform rotational and linear motion, and a first slider (140a) and a second slider (140b) that are respectively connected to the first link (130a) and the second link (130b) and linearly move together along the linear motion direction of the first link (130a) and the second link (130b), so that ultimately a scanning device connected to the first slider (140a) The head (300) can be moved linearly along with the linear movement of the first slider (140a). For example, the scanning head (300) may be connected to the first slider (140a).

[0147] For example, the crank (190) may include a central shaft (191) coupled to a first bevel gear (110a), two first connecting arms (192) each connected to both sides of the central shaft (191), two first shafts (193) each connected to the two first connecting arms (192) and to which a first link (130a) is rotatably coupled, two second connecting arms (194) each connected to the two first shafts (193), and two second shafts (195) each connected to the two second connecting arms (194) and to which a second link (130b) is rotatably coupled.

[0148] For example, a central shaft (191) is connected to the center of the first connecting arm (192), a second connecting arm (194) is arranged mirror-symmetrically to the first connecting arm (192), the center of rotation of the first connecting arm (192) is the center of the first connecting arm (192), and the center of rotation of the second connecting arm (194) may also be the center of the second connecting arm (194).

[0149] Here, the length of the L section from the rotation center of the first connecting arm (192) and the second connecting arm (194) to each end may be equal to the length of the R section from the rotation center of the first connecting arm (192) and the second connecting arm (194) to each other end.

[0150] A wide-range vibration-free linear reciprocating scanning device according to one embodiment of the present invention may further include a first linear stage (150a) and a second linear stage (150b) to which a first slider (140a) and a second slider (140b) are respectively coupled to enable linear movement.

[0151] A wide-range vibration-free linear reciprocating scanning device according to one embodiment of the present invention may further include a counterbalance mass detachably coupled to the second slider (140b). Here, the mass of the counterbalance mass may be determined in a direction such that the total mass of the components transported in conjunction with the first slider (140a) and the total mass of the components transported in conjunction with the second slider (140b) become equal to each other. In other words, the mass of the counterbalance mass may be determined by subtracting the total mass of the components transported in conjunction with the second slider (140b) from the total mass of the components transported in conjunction with the first slider (140a).

[0152] Meanwhile, the parts transported in conjunction with the first slider (140a) may include the R section of the first slider (140a), the first link (130a), the scanning head (300), the first connecting arm (192), and the second connecting arm (194). In addition, the parts transported in conjunction with the second slider (140b) may include the L section of the second slider (140b), the second link (130b), the first connecting arm (192), and the second connecting arm (194).

[0153] In the present invention, photoacoustic imaging is set as a specific application example, and the concept of a vibration-free linear reciprocating scanning device that can completely eliminate mechanical vibration problems that may occur during linear reciprocating scanning regardless of the scan range and speed, along with the necessary elements, is described. However, a person skilled in the art to which the present disclosure pertains will be able to fully understand that the proposed scanning device can be applied, based on the same principles, not only to photoacoustic imaging, but also to all other fields requiring linear reciprocating scanning, such as ultrasonic microscopy used to find defects in large-area LCDs. As described above, the disclosed embodiments have been described with reference to the attached drawings.

[0154] Those skilled in the art will appreciate that the present disclosure can be practiced in forms other than those disclosed herein without altering the technical spirit or essential features of the present disclosure. The disclosed embodiments are illustrative and should not be construed as limiting.

Claims

1. In a wide range, vibration-free, high-speed linear reciprocating scanning device for transporting a scanning head, A first bevel gear rotated by a driving motor; A crank coupled to the first bevel gear and converting the rotational motion of the first bevel gear into linear motion by linking with the first link and the second link; A first link and a second link connected to the crank and moving linearly according to the linear motion converted from the crank; and It includes a first slider and a second slider, which are respectively connected to the first link and the second link and move linearly according to the linear movement of the first link and the second link, The above scanning head is a wide range, vibration-free, high-speed linear reciprocating scanning device, which is connected to the first slider and moves linearly according to the linear movement of the first slider.

2. In paragraph 1, The above crank, A center shaft coupled to the first bevel gear; Two first connecting arms each connected to both sides of the central shaft; Two first shafts, each connected to the two first connecting arms and to which the first link is rotatably coupled; two second connecting arms each connected to the two first shafts; and A wide-range vibration-free linear reciprocating scanning device comprising two second shafts, each connected to the two second connecting arms, and to which the second links are rotatably coupled.

3. In paragraph 2, The central shaft is connected to the center of the first connecting arm, The second connecting arm is positioned symmetrically to the first connecting arm, The center of rotation of the first connecting arm is the center of the first connecting arm, A wide range vibration-free linear reciprocating scanning device, wherein the center of rotation of the second connecting arm is the center of the second connecting arm.

4. In paragraph 3, A wide-range vibration-free linear reciprocating scanning device, wherein the length of the L section from the rotation center of the first connecting arm and the second connecting arm to each end is the same as the length of the R section from the rotation center of the first connecting arm and the second connecting arm to each other end.

5. In paragraph 1, A wide-range vibration-free linear reciprocating scanning device comprising a first linear stage and a second linear stage, each of which is linearly movably coupled with the first slider and the second slider, respectively.

6. In paragraph 5, A wide range vibration-free linear reciprocating scanning device further comprising a counterweight mass detachably coupled to the second slider.

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