Patent Description:
Therapeutic procedures including surgeries or dental examinations using a dental examination system generally employ a microscope, an imaging device, and an illumination device for precise treatments and diagnoses.

Examples known as a dental examination system including an imaging device and an illumination device are an oral cavity observation apparatus for treatment and a dental treatment device described in Patent Literature <NUM> and a dental optical imaging device described in Patent Literature <NUM>.

The oral cavity observation apparatus for treatment according to Patent Literature <NUM> employs coaxial illumination using the same axis to irradiate an observation site in an oral cavity with light emitted from a light source (<NUM>) and to capture images thereof, and a half mirror (<NUM>) is used for irradiation of the observation site.

In the dental optical imaging device according to Patent Literature <NUM>, LED illumination devices (<NUM>, <NUM>), as a target for above-described comparison, are arranged around the lens diagonally to an optical axis AX of an extraoral camera.

Document <CIT> discloses a medical optical imaging device comprising: at least one illumination unit which emits illumination light toward a subject; an imaging section which images the subject; and a controller which controls at least the imaging section, wherein the imaging section includes an imaging lens system and an imaging element receiving an optical image formed by the imaging lens system; the illumination unit comprises a plurality of light emitting elements irradiating the subject; wherein the subject is a surgical site having a deep hole shape; the illumination unit is located in front of the imaging lens system to overlap the imaging lens system as viewed from the subject's side, the illumination unit is located close to a range where the illumination unit does not block an imaging optical path to the imaging element, optical axes of the light emitting elements are arranged to intersect at an acute angle after the optical axes pass through an opening of the hole, and the controller includes a display control unit to display a captured image on a display section.

In the oral cavity observation apparatus for treatment of Patent Literature <NUM>, light from the light source (<NUM>) is transmitted through the half mirror (<NUM>) to be received by a camera system (<NUM>), and about fourfold illuminance is necessary compared to the LED illumination devices arranged around the lens. In addition, the oral cavity observation apparatus for treatment of Patent Literature <NUM> has problems that the need for virtual image formation and the half mirror (<NUM>) increases the body size and thereby increases the cost.

In the dental optical imaging device of Patent Literature <NUM>, optical axes (AL-<NUM>, AL-<NUM>) of the LED illumination devices (<NUM>, <NUM>) form a large angle therebetween. At illuminating a root canal, therefore, light does not reach deep into the root canal and forms a shadow, resulting in low visibility. In a treatment of drilling in a root canal, it is difficult to see the condition of the drilled part in the root canal.

An object of the present invention therefore is to provide a small-sized, inexpensive medical optical imaging device which is capable of illuminating deep in a root canal.

To solve the above problems, according to a first aspect of the present invention, there is provided a medical optical imaging device according to claim <NUM>. Further features according to embodiments of the invention are defined in the dependent claims.

According to the present invention, it is possible to provide a small-sized, inexpensive medical optical imaging device which is capable of illuminating deep in a root canal.

Next, a medical optical imaging device (hereinafter, conveniently referred to as an "imaging device <NUM>") according to an embodiment of the present invention will be described with reference to <FIG>. Prior to description of the imaging device <NUM>, a medical examination apparatus <NUM> on which the imaging device <NUM> is mounted will be described first.

The embodiment will be described such that illustrations in <FIG> of the imaging device <NUM> show: an operation panel section <NUM> in a front side; two grip sections <NUM> in right and left sides; and illumination units <NUM> and an imaging section <NUM> in a lower side.

The medical examination apparatus <NUM> illustrated in <FIG> is medical equipment including: the imaging device <NUM> composed of a digital camera, an optical camera, a digital microscope, an optical microscope, or the like for use in surgeries and the like; an arm <NUM> movably supporting the imaging device <NUM>; and a support column <NUM> supporting the arm <NUM>.

The medical examination apparatus <NUM> only needs to be equipment which includes the imaging device <NUM> and is used for medical diagnoses and treatments in dentistry and the like, and the purpose of use, the installation place, the structures of the arm <NUM> and support column <NUM>, and the like are not limited. Hereinafter, as an example of the medical examination apparatus <NUM>, a dental treatment unit <NUM> on which the imaging device <NUM> is detachably mounted will be described with a root canal Sa (see <FIG>) being a subject S.

The dental treatment unit <NUM> includes a treatment bed <NUM>, the support column <NUM> stood on the treatment bed <NUM>; the arm <NUM> axially supported on upper part of the support column <NUM>; the imaging device <NUM> mounted on the distal end of the arm <NUM>; and a display section <NUM> provided on the support column <NUM>. The dental treatment unit <NUM> only needs to include the treatment bed <NUM>, support column <NUM>, arm <NUM>, and imaging device <NUM>, and the model, type, and the like thereof are not limited.

As illustrated in <FIG>, the treatment bed <NUM> needs to include the support column <NUM> but is not limited to a treatment bed on which a patient lies.

The support column <NUM> is a column member rotatably supporting the proximal end of the arm <NUM>. The support column <NUM> is composed of a metallic cylindrical member through which a harness <NUM> electrically connecting the imaging device <NUM> to a power supply and the like is inserted, for example. At the vertical center of the support column <NUM>, the display section <NUM> is installed. On upper part of the support column <NUM>, the proximal end of the arm <NUM> is swingably provided.

The arm <NUM> is composed of a balance arm arranged to extend from the support column <NUM> to the imaging device <NUM>. The balance arm includes supporting power to elastically support the imaging device <NUM> so as to move the imaging device <NUM> up, down, left, right, forward, and backward by applying a force not less than a predetermined force (any force in a previously set direction of rotation) in the direction of movement. The arm <NUM> is composed of a multi-joint arm including a plurality of joints. The arm <NUM> includes a first arm <NUM> provided on the support column <NUM>, a second arm <NUM> provided on the distal end of the first arm <NUM>, and a third arm <NUM> which is provided on the distal end of the second arm <NUM> and supports the imaging device <NUM>, for example. In the arm <NUM> (the first and second arms <NUM> and <NUM>, for example), the harness <NUM> is inserted with the proximal end being in the support column <NUM> and the distal end being connected to a connector (not illustrated) provided for a housing <NUM> of the imaging device <NUM>.

The first arm <NUM> is mounted to the support column <NUM> so as to rotate horizontally. The first arm <NUM> is elastically supported so as to rotate on a fitting 31a when receiving a horizontal force not less than a predetermined force. The proximal end of the first arm <NUM> is axially supported on the support column <NUM> with a first fixing member <NUM>1b so as not to swing horizontally.

The second arm <NUM> is provided with: a second rotary coupling member 32a which is elastically and swingably supported on a first arm <NUM> side of the second arm <NUM>; a second vertical pivot member (not illustrated) which is elastically and swingably supported within a second rotation coupling member 32a side of the second arm <NUM>; and a joint section 32b which is coupled to the distal end of the second arm <NUM> so as to be held at a proper angle.

As for the third arm <NUM>, the proximal end is rotatably coupled to the joint section 32b of the second arm <NUM>. In the coupling section at the distal end, an attachment member <NUM> to mount the imaging device <NUM> on the tip of the arm <NUM> is provided.

As illustrated in <FIG>, the attachment member <NUM> is a coupling member to detachably couple the distal end of the third arm <NUM> to the imaging device <NUM>. The attachment member <NUM> is composed of, for example, a detachable screw member to couple and fix a connecting section (not illustrated) located at the tip of the third arm <NUM> to a coupling section of the housing <NUM> of the imaging device <NUM>.

As illustrated in <FIG> and <FIG>, the display section <NUM> is a display device to display medical information. The display section <NUM> is swingably installed on the support column <NUM>. The display section <NUM> is electrically connected to the imaging device <NUM>. The medical examination apparatus <NUM> is able to display medical information for use in the medical examination apparatus <NUM>, video information of the imaging device <NUM>, and the like by the display section <NUM>.

As illustrated in <FIG>, the imaging device <NUM> is a digital camera, a surgical light camera, a digital microscope, or any imaging device for dental surgery which is detachably mounted on the tip of the arm <NUM>, as described above. As illustrated in <FIG>, the imaging device <NUM> includes the housing <NUM>, the illumination units <NUM> emitting illumination light toward the subject S, the imaging section <NUM> imaging the subject S, and a controller <NUM> controlling the imaging section <NUM>.

The illumination units <NUM> illustrated in <FIG> may be provided to be fixed to the housing <NUM>. The illumination units <NUM> may be operated manually using light-source driving sections 69a and 69b (see <FIG>) or automatically operated with electricity. In the imaging device <NUM> of <FIG>, accordingly, the illumination units <NUM> do not need the light-source driving sections 69a and 69b, and at least light-source mounted tables <NUM> may be provided to be fixed to the housing <NUM>. Hereinafter, the imaging device <NUM> will be described.

As illustrated in <FIG>, the housing <NUM> is an imaging device body of the imaging device <NUM>. The housing <NUM> is substantially box-shaped. The housing <NUM> includes: the operation panel section <NUM> provided on the front face; the grip sections <NUM> protruded on the right and left lateral faces; switch sections <NUM> provided for the right and left grip sections <NUM>; a connected section (not illustrated) provided on the back face; and the illumination units <NUM> and imaging section <NUM> provided in the bottom face. The connected section (not illustrated) is composed of a substantially rectangular electric connection section which is integrated with the housing <NUM> and includes multiple connection terminals.

As illustrated in <FIG>, in the bottom face of the housing <NUM>, a cover panel 41b is provided. The cover panel 41b includes installation holes 41a which allow illumination lenses <NUM> and an imaging lens system <NUM> to be arranged in an exposed manner. As illustrated in <FIG>, the illumination units <NUM> are provided to be fixed to the housing <NUM> in the example illustrated in these drawings.

In the bottom face of the housing <NUM>, as illustrated in <FIG>, the imaging lens system <NUM> of the imaging section <NUM> located at the center and the illumination lenses <NUM> (the illumination units <NUM>) which are arranged on the front, back, left, and right sides of the periphery of the imaging lens system <NUM> and cover respective four light emitting elements <NUM> to <NUM> are assembled so as to appear when the cover panel 41b is removed.

In the bottom face of the housing <NUM>, when the illumination units <NUM> are removed, as illustrated in <FIG>, the imaging lens system <NUM> appears larger than the imaging lens system <NUM> of <FIG> described above. In other words, the imaging lens system <NUM> is located so that the four light emitting elements <NUM> to <NUM> (the illumination units <NUM>) located in front of the imaging lens system <NUM> overlap the imaging lens system <NUM> as viewed from the subject S side (see <FIG>). As illustrated in <FIG> and <FIG>, the illumination units <NUM> including the four light emitting elements <NUM> to <NUM> are arranged close to the center within a range where the illumination units <NUM> do not block an imaging light path R1 to an imaging element <NUM>.

The operation panel section <NUM> illustrated in <FIG> or <FIG> is a liquid crystal panel section including a plurality of touch switches (not illustrated) for operating the illumination units <NUM> or imaging section <NUM>. The operation panel section <NUM> illustrated in <FIG> is electrically connected to the controller <NUM> of a circuit board <NUM> (see <FIG>). Operation signals from the touch switches (not illustrated) are inputted to the controller <NUM> to drive the illumination units <NUM> and imaging section <NUM>.

The grip sections <NUM> illustrated in <FIG> are members which serve as a handle to operate the illumination units <NUM> or imaging section <NUM>, to mount or demount the housing <NUM> onto or from the arm <NUM>, or adjust the direction of the housing <NUM>. Each grip section <NUM> is composed of a substantially bar-shaped members which is bent in a substantially L-shape (a shape with the both ends bent down) as viewed laterally. The grip sections <NUM> can be used as a handle for carrying the imaging device <NUM> separated from the arm <NUM>.

As illustrated in <FIG>, each switch section <NUM> is an autofocus switch for automatically adjusting the focus on the subject S (the root canal Sa or the like). The switch sections <NUM> may be a foot switch or a switch separately provided from the grip sections <NUM>. As illustrated in <FIG>, the switch sections <NUM> are electrically connected to the controller <NUM> of the circuit board <NUM> (see <FIG>). Operation signals from the switch sections <NUM> are inputted to the controller <NUM> to drive the illumination units <NUM> and imaging section <NUM>.

As illustrated in <FIG> and <FIG>, the illumination units <NUM> are an illumination device to brightly illuminate the subject S, such as the inside of the patient's oral cavity, an objective tooth (tooth), or the inside of the root canal Sa. As illustrated in <FIG>, the illumination units <NUM> are provided with an illumination case body <NUM>, the plurality of (for example, four) light emitting elements <NUM> to <NUM>, the illumination lenses <NUM>, the light-source mounted tables <NUM>, rails <NUM>, a rail mounted board member <NUM>, and light-source driving sections 69a to 69d (see <FIG>).

The light-source driving sections 69a to 69d (see <FIG>) may be manually operated. The illumination units <NUM> do not need to include the light-source driving sections 69a to 69d (see <FIG>) or do not need to include the rails <NUM>, rail mounted board member <NUM>, and light-source driving sections 69a to 69d (see <FIG>) as illustrated in <FIG>. The illumination units <NUM> illustrated in <FIG> therefore may be fixed to the housing <NUM> as described above. Hereinafter, an example of the illumination units <NUM> which includes the rails <NUM>, rail mounted board member <NUM>, and light-source driving sections 69a to 69d (see <FIG>) will be described by way of example.

As illustrated in <FIG>, the illumination case body <NUM> is an illumination unit installation housing provided with the illumination units <NUM>. As illustrated in <FIG>, in the lower side of the illumination case body <NUM>, an illumination cover 60a including a window section 60b and a scale 60c is provided. The window section 60b is composed of a substantially x-shaped opening in which the light emitting elements <NUM> to <NUM> are arranged. The scale 60c is an indication scale that indicates the positions of the light emitting elements <NUM> to <NUM> in the forward, backward, leftward, and rightward (the optical axis Ax (see <FIG>)) directions.

As illustrated in <FIG>, the illumination units <NUM> are configured such that when an imaging distance L1 from the imaging section <NUM> to the subject S is <NUM> to <NUM>, the illuminance around the subject S is not less than <NUM> Lx. The illumination units <NUM> are located in front of the imaging lens system <NUM> so as to overlap the imaging lens system <NUM> as viewed from the subject S side and are located close to the center of the optical axes Ax of the imaging lens system <NUM>. In addition, the illumination units <NUM> are located close to a range where the illumination units <NUM> do not block the imaging optical path R1 to the imaging element <NUM>, preventing occurrence of mechanical vignetting, that is, partial darkening in an image due to the lens hood or the like. The illumination units <NUM> are thereby able to deliver light of the illumination units <NUM> deep into the root canal Sa to brightly illuminate the inside of the root canal Sa.

As illustrated in <FIG>, the illumination units <NUM> are arranged such that the aspect ratio (the ratio of vertical length L4 of the light reception surface to horizontal length L5 of the light reception surface) of the light-reception surface (a sensor light-reception area 71a) of the imaging lens system <NUM> is substantially equal to the aspect ratio of the display size of the display section <NUM> (see <FIG>) that displays an image captured by the imaging section <NUM>.

As illustrated in <FIG> and <FIG>, the light emitting elements <NUM> to <NUM> are composed of four LEDs irradiating the subject S. The light emitting elements <NUM> to <NUM> are mounted on the respective light-source mounted tables <NUM> located on the front, back, left, and right sides in the bottom view. At least one of the plurality of light emitting elements <NUM> to <NUM> is composed of an illuminant having a peak wavelength of <NUM> to <NUM>. For example, the light emitting elements <NUM> and <NUM> positioned on the left and right sides are composed of blue light emitting diodes having a peak wavelength of <NUM>. The light emitting elements <NUM> and <NUM> positioned on the front and back sides are composed of white light emitting diodes with <NUM>,<NUM> Lx. As illustrated in <FIG> and <FIG>, the optical axes 6a of the light emitting elements <NUM> to <NUM> are arranged so as to pass through an opening Sb of the root canal Sa and intersect at an acute angle θ1, allowing for bright illumination within the root canal Sa. The acute angle θ1 is <NUM> to <NUM> degrees in the front-back direction and is <NUM> to <NUM> degrees in the left-right direction, for example. Preferably, the acute angle θ1 is <NUM> to <NUM> degrees in the front-back direction and is <NUM> to <NUM> degrees in the left-right direction.

The light emitting elements <NUM> to <NUM> (the illumination units <NUM>) are arranged so that illumination light beams therefrom intersect on the irradiation area. The light emitting elements <NUM> to <NUM> may include the illumination lenses <NUM> (integrated type) as illustrated in <FIG>, <FIG>, <FIG> or may be separated from the illumination lenses <NUM>.

The type, structure, shape, and the like of the light emitting elements <NUM> to <NUM> are not limited. The light emitting elements <NUM> to <NUM> may also be chip-type LEDs, lens-integrated LEDs, or different type LEDs.

As illustrated in <FIG>, and <FIG>, the illumination lenses <NUM> are transparent lens members that cover the respective four light emitting elements <NUM> to <NUM>. The illumination lenses <NUM> are located under the light emitting elements <NUM> to <NUM> and are fixed to the light-source mounted tables <NUM>. The four illumination lenses <NUM> are arranged so that light beams emitted from the four light emitting elements <NUM> to <NUM> intersect at a single point.

As illustrated in <FIG>, the light-source mounted tables <NUM> are plates with the respective four light emitting elements <NUM> to <NUM> mounted thereon. The light-source mounted tables <NUM> are mounted on the rails <NUM> so as to freely reciprocate and are located so as to move toward and away from the sensor light-reception area 71a by the light-source driving sections 69a to 69d.

As illustrated in <FIG>, the rails <NUM> are guide members that guide movement of the light-source mounted tables <NUM>. When viewed from the bottom, the rails <NUM> are extended from around the center (the sensor light-reception area 71a) forward, backward, leftward, or rightward. The rails <NUM> are arranged in parallel to the rail mounted board member <NUM>.

The rail mounted board member <NUM> illustrated in <FIG> is a board member on which the rails <NUM> are placed. The rail mounted board member <NUM> is horizontally mounted on the illumination case body <NUM>.

As illustrated in <FIG>, the light-source driving sections 69a to 69d are driving devices to individually move the light emitting elements <NUM> to <NUM> toward and away from the center of the four light emitting elements <NUM> to <NUM> (forward, backward, leftward, or rightward) to change the arrangement positions thereof. The light-source driving sections 69a to 69d may be electric driving devices driven by a driving source such as an electric motor or a linear motor or may be manual devices manually operated. Hereinbelow, electric driving devices will be described as an example of the light-source driving sections 69a to 69d.

Each of the light-source driving sections 69a to 69d includes an electric motor <NUM>, a male thread member <NUM>, and a female thread member <NUM>. The light-source driving sections 69a to 69d are located at four places on the front, back, left, and right sides, for example. The light-source driving sections 69a to 69d may be provided at two places on the front and back sides, instead of four places.

The electric motors <NUM> are driving sources to reciprocate the light emitting elements <NUM> to <NUM> placed on the respective light-source mounted tables <NUM>.

The male thread members <NUM> are members rotated and driven by the respective electric motors <NUM>. The male thread members <NUM> are extended along the corresponding rails <NUM> in parallel thereto.

The female thread members <NUM> are members which are screwed with the respective male thread members <NUM> and reciprocate along the corresponding rails <NUM>. The female thread members <NUM> are fixed to the respective light-source mounted tables <NUM> with the light emitting elements <NUM> to <NUM> mounted thereon to drive and reciprocate the light-source mounted tables <NUM>.

As illustrated in <FIG>, the imaging section <NUM> is an imaging device section that images the subject S within the patient's oral cavity. The imaging section <NUM> includes: the imaging lens system <NUM>; the imaging element <NUM> receiving an optical image formed by the imaging lens system <NUM>; and a driving section <NUM> to change the arrangement of the illumination units <NUM>. As illustrated in <FIG>, the imaging section <NUM> includes an autofocus function. An intersection 6b in which the optical axes 6a of the light emitting elements <NUM> to <NUM> intersect at the acute angle (θ1) is located in a focal range of the imaging lens system <NUM> by the autofocus function.

The focus of the imaging section <NUM> is fixed focus. In this case, the fixed focus is located near the intersection 6b in which the optical axes 6a of the light emitting elements <NUM> to <NUM> intersect at the acute angle θ1.

The imaging lens system <NUM> is composed of a plurality of lenses and is located above the illumination units <NUM> (on the imaging element <NUM> side).

The imaging element <NUM> is composed of an image receiving sensor, such as a CMOS or a CCD.

As illustrated in <FIG>, the driving sections <NUM> are irradiation angle adjustment devices which drive the light emitting elements <NUM> to <NUM> so as to increase an irradiation angle θ2a when the imaging section <NUM> reduces the magnification for an image to be captured. As illustrated in <FIG>, the driving section <NUM> drives the light emitting elements <NUM> to <NUM> so as to reduce an irradiation angle θ2b when the imaging section <NUM> increases the magnification for an image to be captured.

As illustrated in <FIG>, each driving section <NUM> includes a fixed section 73a, an illumination unit tilting section 73b, and an electric motor 73c.

The fixed section 73a is a plate member fixed to the light-source mounted table <NUM>. At an end of the fixed section 73a closer to the optical axis Ax of the imaging section <NUM>, the electric motor 73c is provided.

The illumination unit tilting section 73b is a plate member which is tilted about the driving shaft of the electric motor 73c by the electric motor 73c to change the irradiation angle θ2a, θ2b. The proximal end (the end closer to the optical axis Ax of the imaging section <NUM>) of the illumination unit tilting section 73b is swingably coupled to the driving shaft of the electric motor 73c. On the lower surfaces of the illumination unit tilting sections 73b, the light emitting elements <NUM> to <NUM> are mounted.

The electric motor 73c is a driving source to tilt the illumination unit tilting section 73b about the proximal end swingably coupling the illumination unit tilting section 73b and fixed section 73a. As illustrated in <FIG>, the electric motor 73c is electrically connected to an irradiation angle control unit <NUM> and is driven by operation for the operation panel section <NUM> or switch sections <NUM>.

As illustrated in <FIG>, the controller <NUM> includes a display control unit <NUM>, a magnification change unit <NUM>, a drive control unit <NUM>, and the irradiation angle control unit <NUM>. The electric circuit constituting the controller <NUM> is provided in the circuit board <NUM> placed in the housing <NUM> illustrated in <FIG>.

The display control unit <NUM> illustrated in <FIG> is a control device performing control to display a captured image on the display section <NUM>. The display control unit <NUM> performs at least one of moving the imaging lens system <NUM> and executing image processing for imaging data acquired from the imaging element <NUM> such that the illumination units <NUM> are not displayed when the illumination units <NUM> block the imaging optical path R1 to the imaging element <NUM>, and displays the captured image on the display section <NUM>.

The magnification change unit <NUM> is a magnification change device that changes the magnification for an image to be captured by the imaging section <NUM>. The magnification change unit <NUM> changes the magnification by at least one of moving the imaging lens system <NUM> and executing image processing, including magnifying, for the imaging data acquired from the imaging element <NUM>. The driving sections <NUM> are configured to operate based on the magnification.

The drive control unit <NUM> illustrated in <FIG> is a drive control device that automatically controls the driving sections <NUM> to change the arrangement positions of the light emitting elements <NUM> to <NUM> of the illumination units <NUM>. The drive control unit <NUM> is electrically connected individually to the light-source driving sections 69a, 69b, 69c, and 69d.

The irradiation angle control unit <NUM> is an irradiation angle control device to control the angle of the irradiation angle Θ2 of the illumination units <NUM> illustrated in <FIG> and <FIG>. The irradiation angle control unit <NUM> controls the irradiation angle θ2 based on the magnification which was changed by the magnification change unit <NUM> for an image to be captured by the imaging section <NUM>, thus emitting illumination light toward the root canal Sa and providing good visibility deep in the root canal Sa (see <FIG>).

Next, the operation of the medical examination apparatus <NUM> according to the embodiment will be described with reference to <FIG>, mainly <FIG> and <FIG>.

The imaging device <NUM> illustrated in <FIG> is mounted on the tip of the arm <NUM> for use at dental examinations. For a dental examination, first, the first to third arms <NUM>, <NUM>, and <NUM> are swung to align the direction of the imaging device <NUM> with the direction of the position of the root canal Sa as the subject S.

Next, with reference to mainly <FIG>, the following description is given of the case of automatically changing the arrangement of the illumination units <NUM> without manual zooming.

First, the operation panel section <NUM> or switch sections <NUM> illustrated in <FIG> are operated to set the magnification change unit <NUM> to a desired magnification. When the operation of setting the magnification is performed (Yes in Step S1), the controller <NUM> acquires positional information of the illumination units <NUM> for the set magnification (Step S2). When the operation of setting the magnification is not performed (No in Step S1), the controller <NUM> continues to monitor whether the setting operation is performed.

When the positional information of the illumination units <NUM> for the magnification is acquired in Step S2, the irradiation angle control unit <NUM> drives the light-source driving sections 69a to 69d (the electric motors <NUM>) and moves the light emitting elements <NUM> to <NUM> forward, backward, leftward, or rightward to adjust intervals W1 between the light emitting elements <NUM> to <NUM> (the illumination units <NUM>) for arrangement change of the light emitting elements <NUM> to <NUM>. As for the light emitting elements <NUM> to <NUM>, as illustrated in <FIG>, distance L2 between two opposite light emitting elements <NUM> and <NUM> or light emitting elements <NUM> and <NUM> (the intervals W1 between the opposite ones of the light emitting elements <NUM> to <NUM>) is thus adjusted, and the irradiation angle θ2 of the illumination units <NUM> is changed depending on the distance L2.

Next, with reference to mainly <FIG>, the following description is given of the case of automatically changing the arrangement of the illumination units <NUM> for manual zooming.

First, the operation panel section <NUM> or switch sections <NUM> illustrated in <FIG> are operated to set the magnification change unit <NUM> to a desired magnification. When the operation of setting the magnification is performed (Yes in Step S11), the process proceeds to Step S12. When the operation of setting the magnification is not performed (No in Step S11), the controller <NUM> continues to monitor whether the setting operation is performed.

The controller <NUM> acquires arrangement information of the illumination units <NUM> for the set magnification. When the arrangement information of the illumination units <NUM> for the magnification is acquired in Step S12 (Yes in Step S12), the irradiation angle control unit <NUM> drives the light-source driving sections 69a to 69d (the electric motors <NUM>) and moves the light emitting elements <NUM> to <NUM> forward, backward, leftward, or rightward to adjust the intervals W1 between the light emitting elements <NUM> to <NUM> (the illumination units <NUM>) for arrangement change of the light emitting elements <NUM> to <NUM> (Step S16). For the light emitting elements <NUM> to <NUM>, as illustrated in <FIG>, the distance L2 between two opposite light emitting elements <NUM> and <NUM> or light emitting elements <NUM> and <NUM> (the intervals W1 between the opposite ones of the light emitting elements <NUM> to <NUM>) is thus adjusted, and the irradiation angle θ2 of the illumination units <NUM> is changed depending on the distance L2 (Step S16). The process is terminated when the irradiation angle θ2 is changed.

When no arrangement information of the illumination units <NUM> is acquired in Step S12 (No in Step S12), similarly to Step S16, the irradiation angle control unit <NUM> changes the arrangement of the illumination units <NUM> and changes the angle θ1 of the optical axes 6a and the irradiation angle θ2 (Step S13). The process proceeds to Step S14.

Next, the arrangement information of the illumination units <NUM> for the set magnification is newly registered (Step S14). If the registration is to be performed (Yes in Step S14), the arrangement information is registered (Step S15), and the process is terminated. If the registration is not to be performed (No in Step S14), the process is terminated without registration of the arrangement information.

The illumination units <NUM> are thus controlled by the controller <NUM>.

As illustrated in <FIG> or <FIG>, the present invention is the medical optical imaging device <NUM> including: the illumination units <NUM> emitting illumination light toward the subject S; the imaging section <NUM> imaging the subject S; and the controller <NUM> controlling at least the imaging section <NUM>. The imaging section <NUM> includes the imaging lens system <NUM> and the imaging element <NUM> receiving an optical image formed by the imaging lens system <NUM>, and the illumination units <NUM> are located in front of the imaging lens system <NUM> to overlap the imaging lens system <NUM> as viewed from the subject S side.

In the medical optical imaging device <NUM>, since the illumination units <NUM> are located in front of the imaging lens system <NUM> to overlap the imaging lens system <NUM> as viewed from the subject S side, the illumination units <NUM> can be located close to the center of the optical axes Ax of the imaging lens system <NUM>. The illumination units <NUM> are thereby able to deliver light deep into the root canal Sa that is composed of a thin and deep hole to brightly illuminate the inside of the root canal Sa. This improves the efficiency of medical examinations and facilitates treatments.

Furthermore, the illumination units <NUM> may be arranged in the aspect ratio of the light reception surface (the sensor light-reception area 71a) of the imaging lens system <NUM> so as to avoid the optical path to the imaging element <NUM> of the imaging section <NUM>, for example. This implements an illumination structure near coaxial illumination with the surrounding illumination. The illumination units <NUM> need a smaller number of expensive components, such as a mirror, leading to cost reduction of the medical optical imaging device <NUM>.

The present invention thus provides a small-sized and unexpensive medical optical imaging device capable of illuminating deep in a root canal.

As illustrated in <FIG>, <FIG>, or <FIG>, the illumination units <NUM> are composed of the plurality of light emitting elements <NUM> to <NUM> irradiating the subject S. The subject S is the root canal Sa, and the optical axes 6a of the light emitting elements <NUM> to <NUM> are arranged so as to intersect at the acute angle θ1 after passing through the opening Sb of the root canal Sa.

Thus, the illumination units <NUM> of the present invention illustrated in <FIG> are configured so that the optical axes 6a of the light emitting elements <NUM> to <NUM> intersect within the root canal Sa at an angle θ1 which is more acute than an angle θ10 between optical axes 600a of a comparative example (see <FIG>). The intervals W1 between the light emitting elements <NUM> to <NUM> is shorter than an interval W10 between light emitting elements <NUM> and <NUM> (see <FIG>) of the comparative example. In the illumination units <NUM> of the present invention, distance L6 from the opening Sb of the root canal Sa to the intersection 6b of the optical axes 6a can be made longer than distance L60 from the opening Sb of the root canal Sa to the intersection 6b of the optical axes 600a of the comparative example, allowing for imaging of the inside of the root canal Sa, or deep part of the inner wall of the root canal Sa. The illumination units <NUM> of the present invention thus brightly illuminate the inside of the root canal Sa, improving the visibility of the root canal Sa.

As illustrated in <FIG>, the imaging section <NUM> includes an autofocus function, and the intersection 6b in which the optical axes 6a intersect at the acute angle θ1 is located within the focal range of the imaging lens system <NUM> by the autofocus function.

Locating the intersection 6b within the depth of field allows the imaging section <NUM> to provide a clear image of the root cabal Sa at the focal position.

As illustrated in <FIG>, the imaging device <NUM> further includes the grip sections <NUM> to operate the illumination units <NUM> and/or imaging section <NUM> (see <FIG>), and the grip sections <NUM> include the switch sections <NUM> to execute the autofocus function.

Since the grip sections <NUM> to operate the illumination units <NUM> and/or imaging section <NUM> (see <FIG>) include the switch sections <NUM> to execute the autofocus function, the imaging device <NUM> can be moved toward an imaging object while the switch sections <NUM> are operated, thus enhancing the convenience for the user. Furthermore, the illumination units <NUM> and/or the imaging section <NUM> (see <FIG>) can be intuitively operated.

As illustrated in <FIG>, the focus of the imaging section <NUM> is fixed focus, and the fixed focus is located near the intersection 6b in which the optical axes 6a intersect at the acute angle θ1.

The imaging section <NUM> also provides a clear image of the root cabal Sa for the fixed focus.

Furthermore, one of the plurality of light emitting elements <NUM> to <NUM> illustrated in <FIG> emits light with a peak wavelength of <NUM> to <NUM>.

The light emitting elements <NUM> to <NUM> of the illumination units <NUM> include not only white LEDs but also blue LEDs, thus enabling formation of fluorescence images of plaque, resin, and the like. Employing LEDs as the light sources of the illumination units <NUM> can lead to miniaturization of the whole imaging device <NUM> and provide high intensity of light with low-power light sources.

As illustrated in <FIG> and <FIG>, the illumination units <NUM> are located close to a range where the illumination units <NUM> do not block the imaging optical path R1 to the imaging element <NUM>.

Since the illumination units <NUM> are not located within the imaging optical path R1, it is possible to prevent occurrence of mechanical vignetting, that is, partial darkening in an image due to the lens hood or the like.

As illustrated in <FIG>, the controller <NUM> includes the display control unit <NUM> to display a captured image on the display section <NUM>. The display control unit <NUM> performs at least one of moving the imaging lens system <NUM> and executing image processing for imaging data acquired from the imaging element <NUM> such that the illumination units <NUM> are not displayed when the illumination units <NUM> block the imaging optical path R1 to the imaging element <NUM> (see <FIG>), and displays the captured image on the display section <NUM>.

By locating the illumination units <NUM> within the imaging optical path R1, the controller <NUM> can set the illumination units <NUM> closer to the center of the optical axes 6a. Image processing can be executed to display image part not including mechanical vignetting on the display section <NUM>, thus providing the best surgical field information to a surgeon using the medical examination apparatus <NUM>.

As illustrated in <FIG>, for the positional relationship between the angle of view at wide-angle imaging with an angle range A100 being wide and an illumination unit <NUM>, the illumination unit <NUM> is located within the imaging optical path R1 (see <FIG>) with the magnification being low, producing mechanical vignetting. In contrast, according to the present invention, the illumination units <NUM> are located close to a range where the illumination units <NUM> do not block the imaging optical path R1 of the imaging element <NUM> by changing the position of the imaging lens system <NUM> to the telephoto imaging (high-magnification) position with a wide-angle range A being small. This prevents the illumination units <NUM> from producing mechanical vignetting.

For example, the positional information of the imaging lens system <NUM> (mainly a zoom lens) is acquired, and the imaging lens is thereby prevented from being positioned such that the imaging lens can produce mechanical vignetting. This prevents occurrence of mechanical vignetting. Even if the illumination units <NUM> are located within the angle of view, for example, image processing is executed so as to display image part not including mechanical vignetting, thus displaying an image free of mechanical vignetting.

As illustrated in <FIG>, the illumination units <NUM> are configured such that when the imaging distance L1 from the imaging section <NUM> to the subject S is <NUM> to <NUM>, the illuminance around the subject S is not less than <NUM> Lx.

The illumination units <NUM> are thus configured to provide at least a certain light intensity within the imaging distance L1. The illumination units <NUM> therefore are able to irradiate the root canal Sa brightly with light up to the depth (<NUM>, for example) required by the surgeon.

As illustrated in <FIG>, the illumination units <NUM> are arranged such that the aspect ratio of the light-reception surface (the sensor light-reception area 71a) of the imaging lens system <NUM> is substantially equal to the aspect ratio of the display size on the display section <NUM>, of an image captured by the imaging section <NUM>.

The screen aspect ratio of the display section <NUM> therefore is set substantially equal to the aspect ratio of the light-reception surface (the sensor light-reception area 71a) of the imaging lens system <NUM>, thus reducing unnecessary image processing.

As illustrated in <FIG>, the controller <NUM> includes the magnification change unit <NUM> which changes the magnification for an image to be captured by the imaging section <NUM>. The imaging section <NUM> includes the driving sections <NUM> to change the arrangement of the illumination units <NUM>. The magnification change unit <NUM> changes the magnification by at least one of moving the imaging lens system <NUM> and executing image processing for the imaging data acquired from the imaging element <NUM>. The driving sections <NUM> are operated based on the magnification.

When the magnification for an image to be captured by the imaging section <NUM> is changed, the light-reception area is reduced, and the illumination units <NUM> can be moved toward the optical axis so as to deliver illumination light deep into the root canal Sa. In this case, the driving sections <NUM> only need to operate based on the magnification and may operate manually or automatically, for example. When the image magnification is small, the light-reception area is large.

As illustrated in <FIG>, the controller <NUM> includes the drive control unit <NUM> controlling the driving sections <NUM>.

By automatically controlling the driving sections <NUM>, the drive control unit <NUM> easily changes the arrangement of the light emitting elements <NUM> to <NUM> of the illumination units <NUM>.

As illustrated in <FIG>, the controller <NUM> includes the irradiation angle control unit <NUM> to control the irradiation angle θ2 (see <FIG> and <FIG>) of the illumination units <NUM>. The irradiation angle control unit <NUM> controls the irradiation angle θ2 based on the magnification.

By changing the irradiation angle θ2, the irradiation angle control unit <NUM> allows for emission of brighter illumination light toward the root canal Sa, thus improving the visibility within the root canal Sa.

As illustrated in <FIG> or <FIG>, the plurality of illumination units <NUM> are provided, and at least two of the plurality of illumination units <NUM> emit illumination light beams intersecting on the irradiation area.

In the plurality of illumination units <NUM>, the inclination angle θ1 of the optical axes 6a are adjusted so that the illumination light beams intersect at a predetermined position on the optical axis Ax of the imaging section <NUM>, thus providing a shadowless effect (higher illuminance).

The present invention is not limited to the aforementioned embodiment, the invention is limited only by the scope of the appended claims.

<FIG> are views illustrating a first modification of the medical optical imaging device according to the embodiment of the present invention, <FIG> being a schematic perspective view illustrating the structure of the illumination units, <FIG> being a schematic side view illustrating the structure of the illumination units.

The driving mechanism of the aforementioned embodiment illustrated in <FIG>, which include the electric motors <NUM> that move the light emitting elements <NUM> to <NUM>, the male thread members <NUM>, and the female thread members <NUM>, may be illumination unit driving mechanisms 9A including a gear mechanism illustrated in <FIG>.

Each illumination unit driving mechanism 9A includes a first gear 91A driven by an electric motor (not illustrated), a second gear 92A, a third gear 93A, a fourth gear 94A, a thread member 95A, and a support member 96A.

The first gear 91A is an internal gear which is located to surround the four illumination unit driving mechanisms 9A on the front, back, left, and right sides and is engaged with the four second gears 92A on the front, back, left, and right sides to drive the same.

The second gears 92A are spur gears rotationally driven by the first gear 91A.

The third gears 93A are bevel gears provided coaxially and rotated integrally with the corresponding second gears 92A. The shafts coupling the second and third gears 92A and 93A are axially supported by the support member 96A so as to freely rotate.

The fourth gears 94A are bevel gears engaged with the third gears 93A to be rotated.

The thread members 95A are composed of ball screws each having the proximal end fixed to the corresponding fourth gear 94A to be rotated integrally and having the distal end engaged with the corresponding female thread member <NUM> (see <FIG>) provided for the corresponding light-source mounted table <NUM>. The ball screws thereby reciprocate the respective light-source mounted tables <NUM>.

The support member 96A is a plate member supporting the illumination unit driving mechanisms 9A and light-source mounted tables <NUM>.

The light-source mounted tables <NUM> are held on the support member 96A with light-source mounted table support members 96Aa.

The thus-configured first modification provides the same operation effects as the aforementioned embodiment.

<FIG> are views illustrating a second modification as a medical optical imaging device 4B according to the embodiment of the present invention, <FIG> being an explanatory view illustrating the state of illumination units 6B for a smaller magnification, <FIG> being an explanatory view illustrating the state of the illumination units 6B for a larger magnification.

The driving sections <NUM> tilting the illumination units <NUM> illustrated in <FIG> in the aforementioned embodiment may be driving sections 73B each including: an energizing member 73Bd pressing the distal end of an illumination unit tilting section 73Bb; and a limiting member 73Be limiting movement of the illumination unit tilting section 73Bb pressed by the energizing member 73Bd as illustrated in <FIG>.

In this case, an end on the optical axis Ax side of a fixed section 73Ba fixed to the corresponding light-source mounted table <NUM> and an end on the optical axis Ax side of the illumination unit tilting section 73Bb are coupled with a hinge member 73Bc.

The energizing member 73Bd is a member pressing the illumination unit tilting section 73Bb toward the illumination unit <NUM> to tilt the illumination unit tilting section 73Bb with the illumination unit <NUM> mounted thereon, about the hinge member 73Bc. The energizing member 73Bd is composed of a spring member, such as a plate spring or a torsion spring, or a pressing member.

The limiting member 73Be is a stopper supporting the illumination unit tilting section 73Bb tilted toward the illumination unit <NUM> side by the energizing member 73Bd so that the illumination unit tilting section 73Bb is stopped at a desired position. The limiting member 73Be is located at the other end of the illumination unit tilting section 73Bb on the illumination unit <NUM> side.

The driving section 73B thus provides the same operation effects as those of the driving section <NUM> of the aforementioned embodiment.

<FIG> is a perspective view illustrating a third modification as a medical examination apparatus 100C.

In the medical examination apparatus <NUM> described in the above embodiment, the medical optical imaging device <NUM> is mounted on the tip of the arm <NUM> of the dental treatment unit <NUM>. As illustrated in <FIG>, the imaging device <NUM> may be mounted on the tip of an arm 3C of an imaging device stand 1C.

In this case, the stand 1C includes a base 10C, a support column 2C stood on the base 10C, and the arm 3C axially supported on the top of the support column 2C. On the tip of the arm 3C provided at the top of the stand 1C, the imaging device <NUM> is replaceably mounted. The stand 1C allows the imaging device <NUM> to be mounted thereon.

The base 10C includes a plurality of casters 10Ca and a base body 10Cb supporting the plurality of casters 10Ca.

The casters 10Ca are composed of commercially-available casters with stoppers which are screwed to the bottom of the base body 10Cb at four places on the right and left in the front and back sides.

The base body 10Cb is composed of a metallic frame including a pair of right and left transverse frames and a longitudinal frame laid in the center of the pair of transverse frames, for example.

The support column 2C is a column member rotatably supporting the proximal end of the arm 3C. The support column 2C is stood in the center of the base body 10Cb having a substantially H-shape in a plan view. The support column 2C is composed of a metallic cylindrical member through which the harness <NUM> electrically connecting the imaging device <NUM> to a power supply and the like is inserted, for example.

The arm 3C is composed of a balance arm arranged to extend from the support column 2C to the imaging device <NUM>. The balance arm includes supporting power to elastically support the imaging device <NUM> so as to move the imaging device <NUM> up, down, left, right, forward, and backward by applying a force not less than a predetermined force in the direction of movement. The arm 3C, for example, includes a first arm 31C provided on the top of the support column 2C; a second arm 32C, a third arm 33C, and a fourth arm 34C sequentially arranged on the distal end side of the first arm 31C; and an attachment member <NUM> which is provided on the fourth arm 34C and detachably couples the imaging device <NUM> to the fourth arm 34C. In the arm 3C (the first and second arms 31C and 32C, for example), the harness <NUM> is laid with the proximal end inserted in the support column 2C and the distal end to be connected to a connector (not illustrated) provided for the housing <NUM> of the imaging device <NUM>.

The imaging device <NUM> therefore can be mounted for use on the tip of the arm 3C of the stand 1C which is used in dental treatments, examinations, surgeries, and the like.

In one alternative of the invention, the illumination units <NUM> are prevented from producing mechanical vignetting by setting the imaging lens system <NUM> to the telephoto imaging (high-magnification) position with the wide-angle range A being small and moving the illumination units <NUM> closely within the range where the illumination units <NUM> do not block the imaging optical path R1 of the imaging element <NUM>.

Additionally, it is possible to prevent occurrence of mechanical vignetting by detecting the positional information of the imaging lens system <NUM> (mainly the zoom lens) and thereby preventing the imaging lens from moving to such a position that mechanical vignetting can occur.

In a second alternative of the invention, even if the illumination units <NUM> are located within the angle of view, image processing can be executed so as to display image part including no mechanical vignetting, thus displaying an image free of mechanical vignetting.

In the description of the aforementioned embodiment and the third modification, as an installation example of the imaging device <NUM>, the imaging device <NUM> is mounted on the tip of the arm <NUM> of the dental treatment unit <NUM> (see <FIG>) or is mounted on the tip of the arm 3C of the stand 1C (see <FIG>). However, the present invention is not limited to these configurations.

For example, the imaging device <NUM> may be mounted on a ceiling-mounted arm which is provided on the ceiling of a dental treatment room, a floor-mounted arm which is provided on the floor of a dental treatment room, a stand-type arm which is provided on a table, such as a dental treatment table, or the like.

Claim 1:
A medical optical imaging device (<NUM>) comprising:
at least one illumination unit (<NUM>) which is configured to emit illumination light toward a subject;
an imaging section (<NUM>) which is configured to image the subject; and
a controller (<NUM>) which is configured to control at least the imaging section, wherein
the imaging section (<NUM>) includes an imaging lens system (<NUM>) and an imaging element (<NUM>) configured to receive an optical image formed by the imaging lens system, the illumination unit (<NUM>) comprises:
a plurality of light emitting elements (<NUM> - <NUM>) configured to irradiate the subject; and
a plurality of illumination lenses (<NUM>), each of the plurality of illumination lenses covering each of the plurality of light emitting elements;
wherein the subject is a root canal;
the plurality of light emitting elements (<NUM> - <NUM>) consists of a pair of light-emitting elements facing front and back and a pair of light-emitting elements facing left and right; and
the plurality of illumination lenses (<NUM>) is arranged so that light beams emitted from all the light emitting elements intersect at a single point,
the illumination unit (<NUM>) is located in front of the imaging lens system to overlap the imaging lens system as viewed from the subject's side,
the illumination unit is located close to a range where the illumination unit does not block an imaging optical path to the imaging element,
optical axes of the light emitting elements are arranged to intersect at an acute angle after the optical axes pass through an opening of the root canal,
the controller (<NUM>) includes a display control unit (<NUM>) configured to display a captured image on a display section, and
the display control unit (<NUM>) is configured to perform at least one of:
moving the imaging lens system (<NUM>) to change a position of the imaging lens system to a telephoto imaging position with a reduced wide-angle range that prevents mechanical vignetting being produced; and
if the illumination unit is located within the angle of view, executing image processing so as to display image part not including mechanical vignetting for imaging data acquired from the imaging element;
such that the illumination unit is not displayed when the illumination unit blocks an imaging optical path to the imaging element, and the display control unit displays the captured image on the display section.