JP2011027981A - Optical scanning apparatus and endoscope device with the same, and method of optical scanning - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical scanning apparatus that uses a fiber bundle, wherein the time necessary for scanning is reduced. <P>SOLUTION: The optical scanning apparatus includes: a fiber bundle (7) composed of a plurality of fibers; a light emitting unit (3) which emits light directed toward one end face of the fiber bundle, selectively to one of the plurality of fibers; and a scanning unit (9) which scans an object with the light emitted from the other end face of the fiber bundle. The scanning unit performs continuous scanning, and while the scanning unit performs continuous scanning, the light emitting unit selectively emits light to at least one fiber of the fiber bundle. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an optical scanning device, an endoscope apparatus including the optical scanning device, and an optical scanning method. In particular, the present invention relates to an optical scanning device and an optical scanning method suitable for an endoscope, a laser projector, a microscope, and the like.

  An optical scanning device is known that superimposes a plurality of acquired data to increase the resolution of an image (see Patent Document 1). Here, while the laser scanning device (light emitting unit) scans the proximal end of the fiber bundle for one period, the distal end of the fiber bundle is fixed at one position, and data acquisition is performed once. The After the laser scanning device has finished scanning for one period, the process of moving the distal end of the fiber bundle to the next position and stopping it, and then starting scanning again with the laser scanning device is repeated. Thereby, the data acquisition is performed a plurality of times, and the resolution of the image is increased by superimposing the plurality of acquired data.

Special table 2007-516760 gazette

  However, in the above prior art, the fiber bundle distal end performs intermittent scanning, and the scanning of the laser scanning device and the fiber bundle distal end are not performed simultaneously. This increases the time required for scanning. Furthermore, since the fiber bundle is an elastic body, if the distal end of the fiber bundle is moved and stopped, it takes time until the vibration of the distal end subsides after the stop, and the time required for scanning becomes longer.

  An object of the present invention is to shorten the time required for scanning in an optical scanning device using a fiber bundle.

  An optical scanning device according to an aspect of the present invention includes a fiber bundle composed of a plurality of fibers and light that selectively emits light to one of the plurality of fibers toward one end face of the fiber bundle. And a scanning unit that scans an object with light emitted from the other end face of the fiber bundle. The scanning unit continuously scans, and the scanning unit continuously scans. In the meantime, the light emitting unit selectively emits light to at least one fiber of the fiber bundle.

  An optical scanning method according to another aspect of the present invention includes a light emitting step of selectively emitting light to any one of the plurality of fibers toward one end face of a fiber bundle composed of a plurality of fibers. A scanning step of continuously scanning an object with light emitted from the other end face of the fiber bundle, and while the scanning is continuously performed in the scanning step, in the light emission step, the fiber Light is selectively emitted to at least one fiber of the bundle.

  According to the present invention, the time required for scanning can be shortened.

It is a schematic block diagram which shows the structure of an optical scanning device. (A) It is a figure which shows the scanning which a scanning part performs, and shows a 1st period. (B) It is a figure which shows the scanning which a light emission part performs, and shows a 2nd period. (C) It is a figure which shows a 3rd period. (D) It is a figure which shows an example of the scan in a scanning object area | region. (E) It is a figure which shows another example of the scan in a scanning object area | region. It is a figure which shows the 1st Example of the scanning method of a scanning object area | region. (A) It is a figure which shows the scanning pattern of the light emission part in a 1st Example. (B) It is a figure which shows the scanning pattern of the scanning part in a 1st Example. It is a flowchart which shows the 1st Example of the scanning control which a controller performs. It is a figure which shows the 2nd Example of the scanning method of a scanning object area | region. (A) It is a figure which shows the scanning pattern of the light emission part in 2nd Example. (B) It is a figure which shows the scanning pattern of a scanning part in 2nd Example. A thick arrow indicates that the horizontal scanning is performed three times in succession. It is a flowchart which shows the 2nd Example of the scanning control which a controller performs. It is a figure which shows the case where the scanning period of a light emission part is smaller than the scanning period of a scanning part.

  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. However, the present invention is applicable without being limited to this. For example, the optical scanning device may be provided in a projector or a microscope.

  The optical scanning device includes a light source 1, a light emitting unit 3 (light emitting 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 light source 1 is not limited to the three primary colors, and may emit a desired number of light of a desired color.

  The light emitting unit 3 emits light from the light source 1 toward one of the fibers on one end face (proximal end) of the fiber bundle 7. Accordingly, the light emitting unit 3 sequentially selects one optical fiber from the plurality of n optical fibers of the fiber bundle 7 and causes light to enter the selected optical fiber. The light reaches the scanning unit 9 through the selected optical fiber.

  In this embodiment, the light emission part 3 is comprised from the 1st and 2nd galvanometer mirrors 3a and 3b (optical path selection part) which perform a deflection | deviation operation | movement to a mutually perpendicular | vertical direction. The galvanometer mirrors 3a and 3b are controlled by the controller 15 via an actuator (such as a motor) not shown. The light emitting 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 change the angle of the galvanometer mirrors 3a and 3b continuously (analogously). In this case, while the light passes through one fiber, one optical path through the fiber is selected. The controller 15 may numerically (digitally) control the angles of the galvanometer mirrors 3a and 3b.

  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 light emitting unit 3 and the fiber bundle 7. The focal point of the lens group 5 is adjusted so that the light emitted from the light emitting unit 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 by the lens group 13 on a scanning target region (scanning target surface) 100 that is a target of scanning of the target object. 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 scanning unit 9 continuously and periodically scans the scanning target region 100 with the emitted light emitted from the distal end of the fiber bundle. While the scanning unit 9 performs scanning, the light emitting unit 3 selectively emits light to at least one fiber. The scanning unit 9 and the light emitting unit 3 perform scanning simultaneously. While light is incident on a fiber (F1, F2, F3, etc.), a partial region (A1, A2, A3, etc.) corresponding to the fiber is scanned. During each scanning, the scanning position (scanning point) moves within the corresponding partial area (A1, A2, A3, etc.) without any problems. In FIG. 1, a reference scanning position (P1) and other scanning positions (P2) are shown as an example. The reference scanning position corresponds to a scanning point where light from the fiber core reaches 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. Each partial region is adjacent so that it does not overlap or only a part overlaps.

  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 light is adjusted by the polarizing plate 19 or the like. Furthermore, a λ / 2 plate 21 is provided between the two electro-optic elements 9a and 9b to change the polarization direction of 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. Since the controller 15 changes the voltages Vx and Vy, the scanning position can be moved two-dimensionally in the XY plane, so that the scanning unit 9 can perform two-dimensional scanning. 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.

  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 light emitting unit 3.

  In this embodiment, since the optical scanning device is mounted on the endoscope, reflected light from each scanning position (sampling position) among the scanning positions is detected (sampled) by the detector 32 through the detection optical fiber 30. The image data of the scanning target area 100 can be displayed on a monitor or the like.

  The relationship between the scanning of the scanning unit 9 and the scanning of the light emitting unit 3 will be described with reference to FIGS. FIG. 2A shows the scanning state of the scanning unit 9 and the first period. FIG. 2B shows the scanning state of the light emitting unit 3 and the second period. The first period is the time from when the scanning unit 9 deflects light in a predetermined direction until the light is deflected again in this predetermined direction. The second period is a time from when the light emitting unit 3 emits light to a predetermined fiber until the light emitting unit 3 emits light to the predetermined fiber again. FIG. 2C shows a third period which is a time from when light enters a certain fiber until light enters the next fiber.

  First, as shown in FIG. 2D, the second period is preferably an integer multiple of the first period. Since the image data obtained by the detector 32 is the intensity value of the reflected light from the scanning target surface 100 and the time indicating the intensity value, the scanning position on the scanning target surface 100 is obtained from the intensity value and the time. In the case where the image of the scanning target surface 100 is acquired in two steps, the same image is obtained if the second period is an integral multiple of the first period and the scanning position obtained from the intensity value and time is the same. Is imaged. However, if the second period is not an integral multiple of the first period, a different image is captured although the same location is captured from the intensity value and time. Therefore, if the second period is an integral multiple of the first period, the same image data is acquired when it is determined that the same place is imaged from the intensity value and time.

  In particular, as shown in FIG. 2E, if the second period is n times the first period (where n is the number of fibers (integer)), light is transmitted to each fiber during the first period. Incident light is more preferable. The scanning section 9 scans the first partial area in the scanning target area by scanning in the first period, and after the scanning in the first period is completed, the light emitting section 3 enters the optical fiber on which the light is incident. By changing the position, the scanning unit 9 scans the second partial region. Therefore, the scanning target area 100 can be scanned without any problem. The partial area will be described later.

  Moreover, it is preferable that the third period, which is the time from when light enters a certain fiber to when light enters the next fiber, is an integral multiple of the first period. Thus, the scanning unit 9 can scan one or more times before light enters the next fiber. In particular, the third period is preferably equal to the time during which light is incident on each fiber. Thereby, the scanning unit 9 can scan one or more times while light is incident on each fiber. Thereby, for example, the scanning unit 9 can scan the same partial area for a plurality of colors and sample image data for each color, or can sample a plurality of times from the same partial area.

  In the above-described embodiment, the case where the light emitting unit 3 is configured by a galvanometer mirror as a scanning unit is described. However, the light emission part 3 may be comprised from the digital mirror device as a scanning means. The light emitting unit 3 is composed of an LED (light emitting diode) array or an LD (laser diode) array arranged to face the optical fiber, and selectively enters light into any one of the optical fibers of the fiber bundle. May be. Moreover, the light emission part 3 is comprised from the single optical fiber which displaces oscillatingly, and light may selectively inject into any one optical fiber of a fiber bundle.

  Further, in the present embodiment, the case where the scanning unit 9 includes an electro-optical element as a scanning unit is described. However, the scanning unit 9 may be configured by means for scanning the distal end of the fiber bundle as described in Patent Document 1. The scanning unit 9 may be configured by a scanning unit such as a displaceable eccentric lens, an acoustooptic device, and a MEMS (micro-electro-mechanical system) mirror. The decentered lens can be moved in the direction perpendicular to the optical axis or tilted with respect to the optical axis to deflect light.

<Example 1>
FIG. 3 is a diagram showing a first embodiment (specific example) of the scanning method of the scanning target region. In this embodiment, the second period is n times the first period. Note that n is the number (9) of optical fibers in the fiber bundle. For this reason, light is incident on one fiber during the first period. Here, the first period is equal to the scanning period of the scanning unit 9. The second period is equal to the scanning period of the light emitting unit 3.

  FIG. 4A shows a scanning pattern of the light emitting unit 3. FIG. 4B shows a scanning pattern of the scanning unit 9.

  As shown in FIG. 3, while the light emitting unit 3 makes light enter the i-th (1 ≦ i ≦ n) optical fiber, the scanning unit 9 performs the i-th partial region Ai of the scanning target region 100. (Also referred to as a partial scanning region) is scanned. The partial area Ai is an area in which the i-th (1 ≦ i ≦ n) optical fiber is responsible for scanning. The partial areas Ai may not overlap each other or may partially overlap. In the present embodiment, for simplicity, a case will be described in which the partial areas Ai do not overlap each other. In this case, the area of each partial area Ai is substantially equal to a value obtained by dividing the area of the scanning target area 100 by the number n of optical fibers of the fiber bundle 7.

  In FIG. 3, the first to ninth partial regions A1-A9 are shown. In each partial area Ai, nine scanning positions are shown as an example. In the case of an endoscope, the scanning position indicates a sampling position where reflected light is detected from the scanning target surface. The scanning position moves in the partial area Ai in the order of P1, P2, P3, P4, P5, P6, P7, P8, and P9 as shown by the scanning pattern of the arrow in FIG. When scanning with light from the i-th optical fiber is completed in the i-th partial area Ai, the next (i + 1) -th partial area A (i + 1) is the (i + 1) -th Scanned by light from an optical fiber.

  Next, scanning control executed by the controller in the first embodiment will be described with reference to the flowchart of FIG.

  In step S1, 1 is substituted into an integer variable i. In step S2, the light emitting unit 3 is controlled so that light enters the i-th optical fiber. In step S3, the scanning unit 9 is controlled to scan the i-th partial area Ai.

  In step S4, it is determined whether i has reached n. That is, all the partial areas Ai are scanned, and it is determined whether the entire scanning target area 100 has been scanned. If i is less than n, after incrementing i by 1 in step S5, the routine proceeds to step S2. As a result, the (i + 1) th partial region A (i + 1) is scanned by the light from the (i + 1) th optical fiber. If i is greater than or equal to n in step S4, the control is terminated.

<Example 2>
FIG. 6 shows a second embodiment (specific example) of the scanning method. The second embodiment shows a case where the scanning method is a raster scan. In this embodiment, the second period is three times the first period. Further, the scanning cycle of the light emitting unit 3 is three times the scanning cycle of the scanning unit 9. Note that the scanning period of the scanning unit 9 is approximately nine times the first period. The scanning period of the light emitting unit 3 is approximately 9 times the second period.

  FIG. 7A shows a scanning pattern of the light emitting unit 3. FIG. 7B shows a scanning pattern of the scanning unit 9. 7 (a) and 7 (b) indicate that scanning in the horizontal direction (Y direction) is performed continuously m times. Note that m is the number of fibers in the horizontal direction, and m = 3 here.

  In FIG. 6, the first to ninth partial regions A1-A9 are shown. In each partial area Ai, nine scanning positions are shown as an example. Here, the scanning position is P1 → P2 → P3 → P4 → P5 → P6 → P7 → P8 → P9 → P10 → ・ ・ ・ → P19 → ・ ・ ・ → P21 → Move in the order.

  Next, scanning control executed by the controller in the second embodiment will be described with reference to the flowchart of FIG.

  In steps S11, S12, and S13, 1 is substituted into integer variables j, s, and p, respectively. In step S14, the light emitting unit 3 is controlled so that light enters the (j-1) m + pth optical fiber. In step S15, the scanning unit 9 is controlled to perform scanning on the scanning line in the sth column of the (j-1) m + pth partial area Ai (i = (j-1) m + p).

  In step S16, it is determined whether p has reached m. That is, it is determined whether scanning on one scanning line of the scanning target region 100 in FIG. 6 is completed. If p is less than m, the routine proceeds to step S14 after increasing p by 1 in step S17. If p has reached m, the routine proceeds to step S18.

  In step S18, it is determined whether s has reached r. That is, it is determined whether or not scanning is completed in the partial region Ai (i = (j-1) m + 1 to jm) in one horizontal row. Note that s is an integer (1 ≦ s ≦ r), where r is the number of scanning lines included in each partial region Ai (here, r = 3). If s is less than r, in step S19, s is incremented by 1 to perform scanning on the (s + 1) th scanning line, and then the routine proceeds to step S13. If s reaches r, the routine proceeds to step S20.

  In step S20, it is determined whether j has reached k. That is, it is determined whether scanning of the entire scan target area 100 is completed. Note that k is the number of fibers in the vertical direction (X direction) and is an integer satisfying k × m = n. If j is less than k, after incrementing j by 1 in step S21, the routine proceeds to step S12. If j reaches k, the control ends.

  By the above scanning control, first, scanning with light from the first optical fiber is performed in the first row of the first partial region A1. Thereafter, scanning with light from the second optical fiber is performed in the first row of the second partial region A2. Thereafter, scanning with the light from the third optical fiber is performed in the first row of the third partial region A3. Thereafter, in the second column of the first partial area A1, scanning with the light from the first optical fiber starts, and the scanning line in the second column of the scanning target area 100 is scanned in the first column. Scanned like a line. Thereafter, the scanning line in the third column of the scanning target region 100 is also scanned in the same manner as the scanning line in the first column.

  Thereby, the scanning target area 100 is scanned by raster scanning, and it becomes easy to display the image of the scanning target area 100 on the image display (monitor).

<Effect>
Below, the effect of this embodiment is demonstrated.

  The scanning unit continuously performs scanning, and the light emitting unit selectively emits light to at least one fiber while the scanning unit continuously performs scanning (during the first period). Thereby, the time required for scanning can be shortened. Further, even if the scanning unit is composed of a drive device (mechanical scanning means) that scans by displacing the distal end of the fiber bundle, the distal end is rapidly accelerated and decelerated to accelerate the distal end. It is possible to prevent a large load from being applied to the end and the driving device. Furthermore, it is possible to prevent the durability of the fiber bundle and the driving device from being lowered.

  In this embodiment, the scanning period of the light emitting part on the light source side of the fiber bundle is equal to or longer than the scanning period of the scanning part on the distal end side of the fiber bundle, and the scanning of the light emitting part is more than the scanning of the scanning part. slow. Unlike the present embodiment, consider a case where the scanning cycle of the light emitting unit on the light source side is smaller than the scanning cycle of the scanning unit on the distal end side as shown in FIG. That is, the scanning of the light emitting part on the light source side is faster than the scanning part on the distal end side. In this case, if the scanning unit on the distal end side continuously scans, the scanning unit needs to scan to the next sampling position while the light emitting unit scans for one cycle in order to acquire data multiple times. is there. For this reason, if the time difference when light is incident from one fiber (for example, the first fiber) to the next fiber (for example, the second fiber) is Δt and the moving speed of the sampling position by the scanning unit is v, the actual The sampling position deviates from the original sampling position by v × Δt (see FIG. 9). In the present embodiment, the scanning period of the light emitting part is equal to or longer than the scanning period of the scanning part, and such a deviation of the sampling position can be prevented.

  The second period is an integer multiple of the first period. Therefore, when it is determined that the same place is imaged from the intensity value and time, the same image is captured.

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

1 Light source 3 Light emission part (light emission means)
7 Fiber bundle 9 Scanning unit (scanning means)
15 Controller

Claims (11)

A fiber bundle composed of multiple fibers;
A light emitting unit that selectively emits light to any one of the plurality of fibers toward one end face of the fiber bundle,
A scanning unit that scans an object with light emitted from the other end face of the fiber bundle, and
The scanning unit continuously scans,
The optical scanning device, wherein the light emitting unit selectively emits light to at least one fiber of the fiber bundle while the scanning unit continuously performs scanning. The fiber bundle includes a first fiber;
After the scanning unit deflects light in a predetermined direction, the time until the light is deflected again in the predetermined direction is a first period,
When the light emitting unit emits light toward the first fiber and then sets the time until the light is again emitted toward the first fiber as a second period,
The optical scanning device according to claim 1, wherein the second period is an integral multiple of the first period. The fiber bundle has a second fiber;
When the light emitting unit emits light toward the first fiber and then takes the time until the light is emitted toward the second fiber as a third period,
The optical scanning device according to claim 2, wherein the third period is an integral multiple of the first period.   The optical scanning device according to claim 3, wherein the third period is equal to a time during which light is incident on the first fiber. The scanning unit scans a first partial region in a scanning target region of the object in the scanning of the first period;
The scanning unit scans the second partial region by changing an optical fiber through which the light emitting unit makes light incident after the scanning of the first period is completed. The optical scanning device described.   The optical scanning device according to claim 1, wherein the scanning of the object is performed by a raster scan. The light emitting unit and the scanning unit perform periodic scanning,
The optical scanning device according to claim 1, wherein a scanning cycle of the light emitting unit is equal to or longer than a scanning cycle of the scanning unit.   The light emitting unit includes 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 optical scanning device described.   The scanning unit includes at least one of an electro-optic element, an acousto-optic element, an eccentric lens, a MEMS mirror, and a driving device that displaces a distal end of the fiber bundle. The optical scanning device according to 1.   An endoscope apparatus comprising the optical scanning device according to any one of claims 1 to 9. A light emitting step of selectively emitting light to one of the plurality of fibers toward one end face of a fiber bundle constituted by a plurality of fibers;
A scanning step of continuously scanning an object with light emitted from the other end face of the fiber bundle, and
An optical scanning method characterized in that light is selectively emitted to at least one fiber of the fiber bundle in the light emission step while scanning is continuously performed in the scanning step.

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