JP5325640B2 - Endoscope apparatus and optical scanning method thereof - Google Patents

Description

  The present invention relates to an optical scanning device. The optical scanning device is used in, for example, an endoscope, a projector, a microscope, and the like.

  An endoscope optical system that scans an object by deflecting light without mechanical driving by providing an electro-optic element (electro-optic crystal) at the tip is known (Patent Document 1). In this prior art, scanning is performed by deflecting light at high speed by using an electro-optic element.

Special Table 2002-523162

  However, with the above-described conventional technology, it is difficult to obtain a large deflection angle, and it is not possible to scan with a large angle of view.

  It is an object of the present invention to provide an optical scanning device that can scan with a large angle of view and has a wide scanning range.

In an endoscope apparatus including an optical scanning device that scans a target region with light from a light source, the optical scanning device deflects incident light and emits the light toward the target region so as to scan the target region. a scanning unit for a selection incident portion through which light enters into the scanning unit, wherein the selecting incident portion is characterized that you sequentially selecting the optical path from the selected entrance portion to the scanning unit.

According to the present invention, in the endoscope apparatus, the angle of view of the entire optical scanning device is larger than the deflection angle of the scanning unit alone. In the endoscope apparatus, the scanning range of the entire optical scanning device is also wider than the scanning range of the scanning unit alone.

1 is a schematic configuration diagram illustrating an optical scanning device according to a first embodiment. It is a schematic structure figure showing an endoscope concerning a first embodiment. It is a schematic block diagram which shows the optical scanning device which concerns on 2nd embodiment. It is a schematic block diagram which shows the modification of the optical scanning device which concerns on 2nd embodiment. It is a schematic block diagram which shows the optical scanning device which concerns on 3rd embodiment. It is a schematic block diagram which shows the optical scanning device which concerns on 4th embodiment. It is a schematic block diagram which shows the optical scanning device which concerns on 5th embodiment. It is a schematic block diagram which shows the optical scanning device concerning 6th embodiment.

<First embodiment>
A first embodiment of the optical scanning device will be described with reference to FIG. The first embodiment will be described assuming that the optical scanning device is provided in an endoscope or a projector. However, the present invention is applicable without being limited to this. For example, the optical scanning device may be provided in a microscope.

  The optical scanning device includes a light source 1, a selective incident unit 3 (selective incident unit), a fiber bundle 7, and a scanning unit 9 (scanning unit). The fiber bundle 7 is described using a perspective view.

  The light source 1 emits red (R) light (wavelength λr), green (G) light (wavelength λg), and blue (B) light (wavelength λb) as light of the three primary colors. The light source 1 may emit three primary colors by including a white light source and an RGB filter. Alternatively, the light source 1 may be one that emits light of the three primary colors by including red (R), green (G), and blue (B) light emitting diodes or laser diodes. The polarizing plate 19 linearly polarizes light from the light source 1. This facilitates the deflection operation of the electro-optic element described later. When the light from the light source 1 is laser light, the light from the light source 1 is polarized, so that the polarizing plate 19 may not be used. The light source 1 is not limited to the three primary colors, and may emit a desired number of light of a desired color.

  The selective incident unit 3 sequentially selects light paths from the plurality of n optical paths to the scanning unit 9 and causes light to enter the scanning unit 9. Each of the plurality of optical paths passes through one optical fiber of the fiber bundle 7. FIG. 1 shows only the optical paths C1, C2, C3, C4, and C5. When the selective incident unit 3 selects an optical path to the scanning unit 9, at least one of an incident angle and an incident position on the scanning unit 9 is selected. The selective incident unit 3 is disposed on the light source side with respect to the fiber bundle 7, and makes light incident on the scanning unit 9 through the fiber bundle 7. That is, the scanning unit 9 is disposed on the opposite side of the selective incident unit 3 with respect to the fiber bundle 7. The selective incident unit 3 selectively causes the light from the light source 1 to be incident on any one of the plurality of fibers at one end face (proximal end) of the fiber bundle 7.

  In the present embodiment, the selective incident unit 3 includes first and second galvanometer mirrors 3a and 3b (optical path selection units) that perform deflection operations in directions perpendicular to each other. The galvanometer mirrors 3a and 3b are controlled by the controller 15 via an actuator (such as a motor) not shown. The selective incident unit 3 performs two-dimensional scanning at the proximal end of the fiber bundle 7 using the two galvanometer mirrors 3a and 3b. The controller 15 may numerically (digitally) control the angles of the galvanometer mirrors 3a and 3b. Even when the controller 15 continuously (analogously) changes the angles of the galvanometer mirrors 3a and 3b, while the light passes through one fiber, one optical path through the fiber is selected.

  The fiber bundle 7 is composed of a plurality of n optical fibers that are bundled. Each optical fiber transmits the incident light at the proximal end of the fiber bundle 7 and emits it from the other end surface (distal end) of the fiber bundle. Note that n is, for example, several to thousands.

  A lens group 5 is appropriately provided between the selective incident portion 3 and the fiber bundle 7. The focus of the lens group 5 is adjusted so that the light emitted from the selective incident portion 3 enters one optical fiber of the fiber bundle 7. A lens group 11 is also appropriately provided between the fiber bundle 7 and the scanning unit 9. The lens group 11 makes the light from the optical fiber substantially parallel and enters the scanning unit 9. The light from the scanning unit 9 is focused on a scanning target region (scanning target surface) 100 that is a scanning target by the lens group 13. The scanning range is expanded by the lens group 13 at a predetermined magnification. Each of the lens groups 5, 11, and 13 includes one or more lenses.

  The selective incident unit 3, the lens group 5, the lens group 11, and the fiber bundle 7 constitute an optical system 17 that adjusts the optical path of light from the light source 1 so as to be changeable. The optical system 17 can adjust the optical path of the light from the light source so that it can be changed, and can generate off-axis light deviating from the optical axes of the lens groups 5 and 11.

  The scanning unit 9 periodically scans the scanning target region 100 by deflecting the emitted light emitted from the distal end of the fiber bundle. While light is incident on one fiber of the fiber bundle 7, the scanning unit 9 performs scanning with one cycle or a cycle of an integer multiple thereof. While light is incident on a fiber (F1, F2, F3, F4, etc.) included in a certain optical path (C1, C2, C3, C4, etc.), the area corresponding to that optical path and fiber (A1, A2, A3, A4 etc.) is scanned. During each scan, the scanning position (scanning point) moves throughout the corresponding area (A1, A2, A3, A4, etc.). In FIG. 1, as an example, reference scanning positions (P1, P2, P3, P4) and other scanning positions (P1 ′, P2 ′, P3 ′, P4 ′) are shown. The reference scanning position corresponds to a projection point on which the fiber core is projected when the scanning unit 9 is not operating. The other scanning position is a point where light from the scanning unit 9 reaches when the scanning unit 9 is operating.

  For example, while the first light path C1 is selected by the selective incident unit 3, the scanning unit 9 scans the first region A4. The first optical path C1 is an optical path from the selective incident unit 3 to the scanning unit 9 through the first optical fiber F1. While the second light path C2 different from the first optical path C1 is selected by the selective incident unit 3, the scanning unit 9 scans the second area A3 different from the first area A4. The second optical path C2 is an optical path from the selective incident unit 3 to the scanning unit 9 through the second optical fiber F2. The first optical path C1 and the second optical path C2 are adjacent to each other, and the first area A4 and the second area A3 are adjacent to each other. Here, the first region A4 and the second region A3 may not overlap or may partially overlap. In the present embodiment, for simplicity, the case where the first region A4 and the second region A3 do not overlap will be described.

  The deflection angle α of the scanning unit 9 is set so that the scanning range (A1, A2, A3, A4, etc.) of the scanning unit 9 is maximized in a range that does not overlap each other. In the present embodiment, the deflection angle α is represented by a change amount when the angle of the light beam emitted from the lens group 13 is changed by the scanning of the scanning unit 9. The deflection angle α of the scanning unit 9 is adjusted to the maximum size so that the scanning ranges of the scanning unit 9 do not overlap each other at a predetermined interval between the optical paths. Since the selective incident unit 3 sequentially selects the optical path from the plurality of n optical paths to the scanning unit 9, the angle of view β of the entire optical scanning device is several times larger than the deflection angle α of the scanning unit 9 alone. . Note that the angle of view β is represented by the amount of change in the angle of the light beam emitted from the lens group 13 in the entire optical scanning device.

  The scanning unit 9 includes two electro-optic elements (EO) 9a and 9b that perform deflection operations in directions perpendicular to each other. The electro-optic elements 9a and 9b are composed of an electro-optic crystal. When the polarization direction of light and the direction of voltage are parallel, the deflection angle of the electro-optic element becomes large. For this reason, the polarization direction of the light adjusted by the polarizing plate 19 or the like is adjusted to the electric field direction (the direction in which the voltage is applied) of the electro-optic element 9b. Further, in order to facilitate the deflection operation by the voltage of the electro-optical element 9a, a λ / 2 plate 21 is provided between the two electro-optical elements 9a and 9b to change the polarization direction of light by 90 degrees. As a result, the electric field direction of the electro-optic element 9a becomes parallel to the polarization direction of the light.

  The controller (control unit) 15 controls the deflection operation in the Y-axis direction within the YZ plane by applying a voltage Vy in the Y-axis direction to the electrode of the electro-optical element 9a at the subsequent stage. The controller 15 controls the deflection operation in the X-axis direction in the X-Z plane by applying a voltage Vx in the X-axis direction to the electrode of the electro-optical element 9b in the previous stage. The Z axis indicates coordinates in the optical axis direction. When the controller 15 changes the voltages Vx and Vy, the scanning position can be moved two-dimensionally in the XY plane, and two-dimensional scanning by the scanning unit 9 is performed. The controller 15 has two voltage generators for generating the voltages Vx and Vy.

In the electro-optical element, a refractive index distribution (refractive index distribution) is generated by applying a voltage, and light incident on the electro-optical element is deflected and emitted from the electro-optical element. Further, the refractive index distribution changes depending on the applied voltage. For this reason, by changing the voltage applied to the electro-optical element, the direction of the light beam emitted from the electro-optical element changes. Thereby, the spot of the light irradiated to a target object can be moved. For example, an electric field is generated in an electro-optic element (for example, KTa _1-x Nb _x O ₃ ) by injecting a current to incline the electric field in the direction of the applied voltage, thereby obtaining a large refractive index gradient. (See JP2008-158325A, JP2007-310104A, etc.).

  The controller (control unit) 15 includes a central processing unit (CPU) and a memory. The controller 15 also controls the light source 1 and the galvanometer mirrors 3 a and 3 b of the selective incident unit 3.

  For example, the optical scanning device is mounted on the endoscope 200 as shown in FIG. In this case, the reflected light from the scanning position is detected by a detector (not shown) through the detection optical fiber 39, and an image of the scanning target surface 100 can be displayed on a monitor or the like. For example, the optical scanning device is mounted on a projector. In this case, a predetermined image can be displayed on the scanning target surface 100 such as a screen.

  In the present embodiment, the optical scanning device may be configured without the fiber bundle.

The action-effect light scanning device sequentially selects a scanning unit that deflects incident light and emits the light toward the target region so as to scan the target region, and an optical path to the scanning unit, and causes the light to enter the scanning unit. A selective incident portion. For this reason, the angle of view of the entire optical scanning device is larger than the deflection angle of the scanning unit alone. Further, the scanning range of the entire optical scanning device is wider than the scanning range of the scanning unit alone. The selective incident part and the scanning part respectively perform two-dimensional scanning, so that the optical scanning device has a wide two-dimensional scanning range.

  While the first optical path is selected by the selective incident unit, the scanning unit scans the first region. While the second light path different from the first optical path is selected by the selective incident part, the scanning part scans the second area different from the first area. Furthermore, the first region and the second region do not overlap or only partially overlap. For this reason, the scanning range of the whole optical scanning device becomes wider than the scanning range of the scanning unit alone.

  The optical scanning device includes a fiber bundle composed of a plurality of optical fibers, and the selective incident unit is disposed on the light source side of the fiber bundle, and causes light to enter the scanning unit via the fiber bundle. Therefore, scanning can be performed using a light beam having a minute beam diameter that has passed through the fiber bundle. Moreover, the optical path to the scanning unit is selected by selecting each fiber of the fiber bundle. By this selection, at least one of the incident angle and the incident position of light on the scanning unit is selected, and the light enters the scanning unit. For this reason, one scanning range corresponds to each optical path, and a wide scanning range is obtained by sequentially changing the optical path to the scanning unit.

  Since the scanning unit includes an electro-optical element, scanning can be easily performed. Since the selective incident portion causes the polarized light to enter the electro-optical element, the deflection angle of the electro-optical element is increased. Since the scanning unit includes two electro-optic elements, two-dimensional scanning can be performed. Since the two electro-optical elements scan in directions orthogonal to each other, the scanning area can be increased. Since the λ / 2 plate is disposed between the two electro-optic elements, the electric field direction of the latter electro-optic element and the polarization direction can be made parallel to increase the deflection angle of the latter electro-optic element.

<Second embodiment>
Referring to FIG. 3, in the second embodiment, the selective incident unit 3 includes a digital mirror device (DMD) 30 as an optical path selection unit instead of the galvanometer mirrors 3a and 3b. Other configurations are the same as those in the first embodiment.

  The DMD 30 includes a plurality of n micromirrors. Each of the plurality of micromirrors reflects a part of light from the light source 1 toward the scanning unit 9 when selected and driven by the controller 15. The plurality of micromirrors are electrostatically driven by a voltage from a controller 15 having a voltage source, for example. That is, each micromirror reflects a part of the light from the light source 1 toward the fiber bundle 7 in accordance with a command from the controller 15. The reflected light from each minute mirror has a minute beam diameter. The reflected light of the micromirror of the DMD 30 enters the scanning unit 9 through one fiber of the fiber bundle 7. There are a plurality of n optical paths corresponding to the plurality of n micromirrors. FIG. 3 shows only the optical paths C1, C2, C3, C4, and C5. The controller 15 sequentially selects and drives the micromirrors. Thereby, the optical paths from the plurality of n optical paths to the scanning unit 9 are sequentially selected, and light enters the scanning unit 9. While light is incident on the scanning unit 9 through a certain optical path (C1, C2, C3, C4, etc.), a region (A1, A2, A3, A4, etc.) corresponding to the optical path is scanned.

  The second embodiment also has the same effects as the first embodiment. As in the first embodiment, the selective incident unit 3 sequentially selects the optical paths from the plurality of n optical paths to the scanning unit 9, so that the angle of view β of the entire optical scanning device is larger than the deflection angle α of the scanning unit 9 alone. Will be several times larger.

  As shown in FIG. 4, the optical scanning device may be configured without the fiber bundle.

<Third embodiment>
Referring to FIG. 5, in the second embodiment, the selective incident unit 3 includes an LED array 32 as an optical path selection unit instead of the galvanometer mirrors 3 a and 3 b. Other configurations are the same as those in the first embodiment.

  The LED array 32 includes an array of a plurality of n LEDs (light emitting diodes). The plurality of LEDs 33 may be single color or multicolor. Each LED 33 is provided to face the end of the corresponding fiber of the fiber bundle 7. More specifically, each LED 33 faces the fiber bundle 7 via a microlens array (not shown) or a lens (not shown). Accordingly, the light from each LED 33 is collected by the microlens array or the lens and then enters the end of the corresponding fiber of the fiber bundle 7.

  The LED array 32 operates in accordance with a command from the controller 15 via the drive circuit 34. When the LED selected by the controller 15 emits light, one optical path is selected from a plurality of n optical paths. While light is incident on the scanning unit 9 through a certain optical path (C1, C2, C3, C4, etc.), a region (A1, A2, A3, A4, etc.) corresponding to the optical path is scanned.

  Note that FIG. 5 shows a case where a single-color LED array 32 is provided for simplicity. Alternatively, for example, a desired number of LED arrays may be provided. In this case, light emitted from a set of LEDs (for example, RGB) is reflected by the mirror, then combined, and enters the end of the corresponding fiber of the fiber bundle 7. Alternatively, one end face of one fiber may be branched into three, and LEDs of different colors may be provided to face each end face.

  Further, instead of the LED array 33, an LD (laser diode) array may be used.

  Further, the optical scanning device may be configured without the fiber bundle.

  The third embodiment also has the same effects as the first embodiment.

<Fourth embodiment>
Referring to FIG. 6, in the fourth embodiment, the selective incident unit 3 includes a single single mode fiber 36 (single mode optical fiber) that vibrates as an optical path selection unit instead of the galvanometer mirrors 3 a and 3 b. The single mode fiber 36 is oscillated and displaced by an actuator such as an electric motor. That is, the single mode fiber 36 vibrates rotationally with one end thereof as a substantially fixed point. The controller 15 controls the operation of the actuator. In FIG. 6, the single mode fiber 36 is displaced to positions B1, B2, B3, B4, and B5 in order. After the displacement to the position B5, the single mode fiber 36 is displaced in the order of the positions B5, B4, B3, B2, B1.

  For example, the optical fiber 36 may be rotationally displaced by a predetermined angle, and the scanning unit 9 may perform periodic scanning of one cycle or an integral multiple thereof every time the optical fiber 36 rotates by a predetermined angle. In this case, each time the optical fiber 36 rotates by a predetermined angle, one optical path is selected. While light is incident on the scanning unit 9 through a certain optical path (C1, C2, C3, C4, etc.), a region (A1, A2, A3, A4, etc.) corresponding to the optical path is scanned.

  Note that the single mode fiber 36 is not limited to rotational vibration, and may be two-dimensionally scanned in the XY plane. For example, one end of the single mode fiber 36 may be fixed, and the other end may perform non-rotational periodic vibration or perform random scanning. Further, both ends of the single mode fiber 36 may be fixed, and the direction of one end (object side) may be changed.

  The fourth embodiment also has the same effects as the first embodiment.

<Fifth embodiment>
Referring to FIG. 7, in the fifth embodiment, the scanning unit 9 includes an eccentric lens 38 instead of the electro-optical elements 9a and 9b. Other configurations are the same as those in the first embodiment.

  The eccentric lens 38 is moved in the direction perpendicular to the optical axis by an actuator (not shown). Alternatively, the eccentric lens 38 is tilted with respect to the optical axis by an actuator (not shown). The actuator is controlled by the controller 15. Thereby, the eccentric lens 38 can deflect light. While the light is incident on the scanning unit 9 through a certain optical path (C1, C2, C3, C4, etc.), the eccentric lens 38 tilts or moves, so that a region (A1, A2, A3) corresponding to the optical path is obtained. , A4, etc.) are scanned.

  The optical scanning device may be configured without the fiber bundle.

  The fifth embodiment also has the same effects as the first embodiment.

<Sixth embodiment>
Referring to FIG. 8, in the sixth embodiment, the scanning unit 9 includes acoustooptic elements 40a and 40b instead of the electrooptic elements 9a and 9b. Other configurations are the same as those in the first embodiment.

  The acousto-optic elements 40a and 40b respectively apply ultrasonic waves in the Y-axis and X-axis directions by ultrasonic transducers made of piezoelectric elements. Thereby, the acoustooptic devices 40a and 40b can deflect light in the Y-axis direction and the X-axis direction, respectively.

  The controller 15 has an AC voltage source, and applies an AC voltage signal to the ultrasonic transducers of the acousto-optic elements 40a and 40b. The deflection directions of the acoustooptic elements 40a and 40b depend on the frequency of the AC voltage signal (frequency of the ultrasonic wave). The controller 15 can change the deflection direction by changing the frequency of the AC voltage signal. While the light is incident on the scanning unit 9 through a certain optical path (C1, C2, C3, C4, etc.), the acoustooptic elements 40a and 40b operate, so that regions corresponding to the optical path (A1, A2, A3, A4, etc.) are scanned.

  The optical scanning device may be configured without the fiber bundle.

  The sixth embodiment also has the same effects as the first embodiment.

<Other embodiments>
As another embodiment, the scanning unit 9 may include a MEMS (micro-electro-mechanical system) mirror that performs scanning instead of the electro-optic elements 9a and 9b. The MEMS mirror may be one that is electrostatically driven by the controller 15 and swings. The MEMS mirror reflects the light beam incident on the scanning unit 9. When the MEMS mirror is swung, the direction of the reflected light is changed, and scanning is performed. Other configurations are the same as those in the first embodiment.

  The present invention is not limited to the above-described embodiments, and it is apparent that various modifications can be made within the scope of the technical idea.

DESCRIPTION OF SYMBOLS 1 Light source 3 Selective entrance part 3a, 3b Galvano mirror 5, 11, 13 Lens group 7 Fiber bundle 9 Scan part 9a, 9b Electro-optic element 15 Controller 17 Optical system 19 Polarizing plate 21 λ / 2 plate 30 Digital mirror device (DMD)
32 LED array 34 Drive circuit 36 Single mode fiber 38 Eccentric lens 40a, 40b Acousto-optic device 100 Scan target area

Claims (12)

In an endoscope apparatus provided with an optical scanning device that scans a target area with light from a light source,
The optical scanning device includes:
A scanning unit that deflects incident light and emits the light toward the target region so as to scan the target region;
A selective incident part for making light incident on the scanning part ,
The selection incidence unit, the endoscope apparatus characterized that you sequentially selecting the optical path to the scanning unit from the selected incident portion.   The selective incident unit includes an optical path selection unit including at least one of a galvano mirror, a digital mirror device, an LED array, an LD array, and a single optical fiber that is oscillatingly displaced. The endoscope apparatus according to claim 1.   The endoscope apparatus according to claim 1, wherein each of the selective incident unit and the scanning unit performs two-dimensional scanning. The optical scanning device includes a fiber bundle composed of a plurality of optical fibers,
The endoscope apparatus according to claim 3, wherein the selective incident unit is disposed on a light source side of the fiber bundle and causes light to be incident on the scanning unit via the fiber bundle. The selection incidence portion, by selecting the optical path to the scanning unit from the selected entrance portion, and selecting at least one of the incident position and the incident angle of light to the scanning unit, the light to the scanning unit The endoscope apparatus according to claim 1, wherein the endoscope apparatus is incident.   The endoscope apparatus according to claim 1, wherein the scanning unit includes an electro-optical element, and the selective incident unit causes polarized light to enter the electro-optical element.   The endoscope apparatus according to claim 1, wherein the scanning unit includes two electro-optic elements.   The endoscope apparatus according to claim 7, wherein the two electro-optical elements scan in directions orthogonal to each other.   The endoscope apparatus according to claim 7, wherein a λ / 2 plate is disposed between the two electro-optic elements. While the first optical path is selected by the selective incident unit, the scanning unit scans the first region,
The scanning unit scans a second region different from the first region while the second light path different from the first optical path is selected by the selective incident unit. The endoscope apparatus described.   The endoscope apparatus according to claim 1, wherein the scanning unit includes at least one of an electro-optic element, an eccentric lens, an acousto-optic element, and a MEMS mirror. In an optical scanning method of an endoscope apparatus that scans a target area with light from a light source,
Selecting a first optical path from the selective incident part to the scanning part and causing the selective incident part to enter the scanning part; and
Deflecting the light incident on the scanning unit through the first optical path so as to scan the target area and emitting the light toward the target area;
The selection incidence portion, the first an optical path different from the second optical path, the steps of selecting a second optical path from the selected incident portion to the scanning portion, light is incident to the scanning unit ,
Deflecting the light incident through the second optical path and emitting the light toward the target area so as to scan the target area; and
An optical scanning method for an endoscope apparatus, comprising:

Images