Patent Description:
A white light source is generally used as illuminating light of an endoscopic device, and an endoscopic device including a light source for highlighting a state of a mucosal tissue through illumination with light of a specific narrowed band wavelength or for observation with special light such as observation of self-fluorescence from a fluorescent substance precedently administered is recently put to practical use (<CIT>, <CIT>). When such an endoscopic device is employed, biological information that cannot be obtained from general observation images, such as a neovascular fine structure produced in a mucosal layer or a submucosal layer, or a highlighted lesion, may be easily visualized.

In accordance with the preamble of claim <NUM>, <CIT> discloses an endoscopic device in which the color tone can be changed by combining the light of the three primary colors (blue, green, red). Further, the color tone can also be adjusted by combining two of said colors.

<CIT> discloses an endoscopic device having a single light source. Different wavelengths are obtained by making use of a color filtering wheel. This prior art endoscopic device includes a switch which is used for switching between a fluorescence image mode and a normal image mode.

<CIT> discloses an endoscopic device also including a single light source combined with a color filtering wheel.

Furthermore, the illuminating light of an endoscopic device is desired to be set to a color tone suitable to diagnosis because a color tone of a light source proper to be employed for finding a lesion differs depending upon a site to be observed. For example, in diagnosis of the large intestine, a lesion may be more definitely identified by observing the form and the color of the inside of the large intestine in observation with low magnifying power and observing blood vessels of a surface layer in observation with high magnifying power. In the endoscopic device, however, although the illuminating light may be switched between white light for general observation and special light for observation with special light, the color tone of the illuminating light cannot be arbitrarily changed in accordance with an observation target or in accordance with various diagnosis situations such as enlargement observation.

Document <CIT> discloses the preamble of claim <NUM>.

An object of the invention is providing an endoscopic device capable of arbitrarily changing a color tone of illuminating light in accordance with an observation target or a diagnosis situation.

The present invention provides an endoscopic device according to claim <NUM>.

According to the endoscopic device of the invention, a color tone of illuminating light may be arbitrarily changed in accordance with an observation target or a diagnosis situation.

Now, an embodiment of the invention will be described in detail with reference to the accompanying drawings.

<FIG> is a block diagram conceptually illustrating the structure of an endoscopic device used for explaining the embodiment of the invention, and <FIG> is a diagram illustrating an exemplary external structure of the endoscopic device of <FIG>.

The endoscopic device <NUM> includes an endoscope <NUM> and a controller <NUM> connected to the endoscope <NUM>. The controller <NUM> is connected to a display section <NUM> for displaying image information and the like and an input section <NUM> for accepting an input operation. The endoscope <NUM> is an electronic endoscope including an illuminating light optical system for emitting illuminating light from a tip of an endoscope insert section <NUM> and an imaging optical system including an imaging device <NUM> for obtaining a pickup image of a region to be observed.

As illustrated in <FIG> and <FIG>, the endoscope <NUM> includes the endoscope insert section <NUM> to be inserted into an observed body, an operation section <NUM> for operating to bend the tip of the endoscope insert section <NUM> to observe, and connector sections 25A and 25B for removably connecting the endoscope <NUM> to the controller <NUM>. Although not shown in the drawings, various channels such as a forceps channel for inserting a tissue collecting tool or the like and a channel for supplying air or water are provided inside the endoscope <NUM>.

The endoscope insert section <NUM> includes a flexible soft portion <NUM>, a bending portion <NUM> and a tip portion (hereinafter referred to also as the endoscope tip portion) <NUM>. In the endoscope tip portion <NUM>, radiation ports 37A and 37B through which a region to be observed is radiated with light and the imaging device <NUM> for obtaining image information of the region to be observed, such as a CCD (Charge Coupled Device) image sensor or a CMOS (Complementary Metal-Oxide Semiconductor) image sensor, are provided. It is noted that the imaging device <NUM> is provided with an objective lens unit <NUM> having a zooming function for controlling a focal distance and an automatic focusing function for focusing on a subject.

The bending portion <NUM> is disposed between the soft portion <NUM> and the tip portion <NUM> and is bendable through a rotation operation of an angle knob <NUM> disposed on the operation section <NUM> or a function of an actuator. This bending portion <NUM> may be bent at an arbitrary angle in an arbitrary direction in accordance with a site or the like of a subject of the endoscope <NUM>, so that the radiation ports 37A and 37B of the endoscope tip portion <NUM> and the observation direction of the imaging device <NUM> may be made to aim at a desired observation site. Furthermore, although not shown in the drawings, the radiation ports 37A and 37B of the endoscope insert portion <NUM> are provided with cover glasses or lenses.

The controller <NUM> includes a light source device <NUM> for generating illuminating light to be supplied to the radiation ports 37A and 38B of the endoscope tip portion <NUM> and a processor <NUM> for image processing image signals supplied from the imaging device <NUM>, and is connected to the endoscope <NUM> through the connector sections 25A and 25B. Also, the processor <NUM> is connected to the display section <NUM> and the input section <NUM> as described above. The processor <NUM> performs image processing on image signals transmitted from the endoscope <NUM> on the basis of an instruction given through the operation section <NUM> of the endoscope <NUM> or the input section <NUM>, so as to generate a display image and supply the generated image to the display section <NUM>.

The light source device <NUM> includes, as light sources, a blue laser light source (i.e., a first light source) <NUM> with a center wavelength of <NUM> and a violet laser light source (i.e., a second light source) <NUM> with a center wavelength of <NUM>. Light emitted from semiconductor light emitting diodes of these light sources <NUM> and <NUM> is individually controlled by a light source control section <NUM>, so that a light quantity ratio between output light of the blue laser light source <NUM> and output light of the violet laser light source <NUM> may be changed. In other words, the light source control section <NUM> functions as color tone controlling means for the illuminating light.

As each of the blue laser light source <NUM> and the violet laser light source <NUM>, a broad-area type InGaN-based laser diode may be used, and alternatively, an InGaNAs-based laser diode or a GaNAs-based laser diode may be used. Alternatively, a luminous element such as a light emitting diode may be used as the light source.

Laser beams emitted from the light sources <NUM> and <NUM> are input to an optical fiber by a condensing lens (not shown) and transmitted to the connector section 25A through a combiner <NUM>, that is, a multiplexer, and a coupler <NUM>, that is, a demultiplexer. It is noted that this structure does not limit the invention but the laser beams emitted from the light sources <NUM> and <NUM> may be directly sent to the connector section 25A without using the combiner <NUM> and the coupler <NUM>.

The laser beams supplied to the connector section 25A and obtained by multiplexing the blue laser beams of the center wavelength of <NUM> and the violet laser beams of the center wavelength of <NUM> are propagated to the endoscope tip portion <NUM> of the endoscope <NUM> through optical fibers 55A and 55B. The blue laser beams excite a phosphor <NUM> corresponding to a wavelength conversion member disposed at the light outputting end of each of the optical fibers 55A and 55B of the endoscope tip portion <NUM>, so as to cause fluorescence emission. Also, part of the blue laser beams directly passes through the phosphor <NUM>. The violet laser beams pass through the phosphor <NUM> without exciting it, so as to work as illuminating light of a narrowed band wavelength.

Each of the optical fibers 55A and 55B is a multimode fiber, and for example, a thin cable with a core diameter of <NUM>, a cladding diameter of <NUM> and a diameter including a protective layer working as a casing of <NUM> through <NUM> may be used.

The phosphor <NUM> includes a plurality of kinds of phosphors that absorb part of the blue laser beams for emitting green-to-yellow light when excited (such as a YAG-based phosphor and a phosphor including BAM (BaMgAl<NUM>O<NUM>) or the like). Thus, the green to yellow light emitted through excitation under radiation of the blue laser beams and the part of the blue laser beams not absorbed but transmitted by the phosphor <NUM> are multiplexed, so as to give white (pseudo white) illuminating light. When a semiconductor light emitting diode is used as the excitation light source as in this exemplary structure, white light with high intensity may be obtained with high luminous efficacy, and the intensity of the white light may be easily controlled. In addition, change in the color temperature and the chromaticity of the white light may be suppressed to be small.

The phosphor <NUM> and a light deflecting/diffusing member <NUM> may prevent phenomenon such as noise superposition obstructing imaging derived from speckle caused due to coherence of laser beams or occurrence of flicker in displaying dynamic images. Furthermore, in consideration of a difference in refractive index between a fluorescent material and a fixing/setting resin working as a filler included in the phosphor, the phosphor <NUM> is preferably made of a material having such particle sizes of the fluorescent material and the filler that light of the infrared region is little absorbed and largely diffused. Thus, the diffusion effect for light of red or the infrared region may be increased without lowering the light intensity, and there is no need to provide optical path changing means such as a concave lens and the optical loss may be reduced.

<FIG> is a graph illustrating emission spectra of the violet laser beam emitted from the violet laser light source <NUM>, the blue laser beam emitted from the blue laser light source <NUM> and the light obtained through the wavelength conversion, by the phosphor <NUM>, of the blue laser beam. The violet laser beam is expressed by an emission line with a center wavelength of <NUM> (i.e., a profile A). Also, the blue laser beam is expressed by an emission line with a center wavelength of <NUM>, and the light emitted through excitation from the phosphor <NUM> under radiation of the blue laser beam has a spectral intensity distribution in which the emission intensity is increased in a wavelength band of approximately <NUM> through <NUM>. The light emitted through the excitation and a profile B derived from the blue laser beam together generate the aforementioned white light.

At this point, white light herein does not strictly mean merely light including all wavelength components of visible light but may be light including light of specific wavelength bands such as R, G and B. For example, light including wavelength components from green to red or light including wavelength components from blue to green is also regarded as white light in a broad sense.

In this endoscopic device <NUM>, the luminous intensities of the profile A and the profile B are controlled to be relatively increased/decreased by the light source control section <NUM> so as to generate illuminating light of an arbitrary color tone. Therefore, illuminating light with different characteristics may be obtained depending upon a mixing ratio between the profiles A and B.

Referring to <FIG> again, the illuminating light generated from the blue laser beams, the light emitted through the excitation of the phosphor <NUM> and the violet laser beams is radiated to the region to be observed of the subject from the tip portion <NUM> of the endoscope <NUM>. Then, the state of the region to be observed radiated by the illuminating light is focused on the imaging device <NUM> by the objective lens unit <NUM> for obtaining a pickup image. The objective lens unit <NUM> is specified for the zooming magnifying power by a zoom control section <NUM> so as to obtain the focus with the specified zooming magnifying power.

An image signal of the pickup image output from the imaging device <NUM> after the imaging is transmitted to an A/D converter <NUM> through a scope cable <NUM> to be converted into a digital signal, and the digital signal is input to a control section <NUM> of the processor <NUM> through the connector section 25B. In the control section <NUM>, the input digital image signal is converted into image data for performing appropriate image processing, so as to generate desired output image information. Then, the thus obtained image information is displayed on the display section <NUM> as an endoscope observation image, and is stored in a memory section <NUM> of a memory or a storage device if necessary.

The memory section <NUM> may be included in the processor <NUM> as illustrated in <FIG> or may be connected to the processor <NUM> through a network. It is noted that information of an endoscope observation image stored in the memory section <NUM> may be recorded in association with information of a light quantity ratio employed in obtaining the pickup image. In this manner, the stored endoscope observation image may be accurately read after the observation with the endoscope and appropriate image processing for, for example, standardizing the image may be performed in accordance with the light quantity ratio, and thus, the application range of the endoscope observation image may be expanded.

In the endoscopic device <NUM> having the aforementioned structure, the color tone of the illuminating light emitted from the endoscope tip portion <NUM> may be continuously changed. Furthermore, since the laser light source is used, the color tone may be controlled with high resolution, the color tone is minimally changed with time, and the light quantity may be controlled with high responsibility. Moreover, since the luminous efficacy is high, the power consumption may be reduced. In endoscopic diagnosis, a lesion may be easily found or diagnosed by setting the color tone of the illuminating light to a color tone suitable to the diagnosis, and therefore, it is significant for improvement of diagnostic accuracy to make the illuminating light changeable at arbitrary timing during the endoscopic diagnosis. Now, examples of the structure of the endoscopic device in which the color tone of the illuminating light is changed in accordance with any of various parameters will be successively described.

First, an exemplary structure in which the color tone is changed in accordance with a distance between a region to be observed and the endoscope tip portion will be described. An observation distance, that is, a distance between the region to be observed and the endoscope tip portion <NUM> (see <FIG>), is set to be small in enlargement observation and to be large in observation with a large visual field, and therefore, as the observation magnifying power is higher, the observation distance is smaller. The observation magnifying power is arbitrarily set by an operator of the endoscope by using a zooming mechanism of the objective lens unit <NUM>. At this point, an exemplary structure of the objective lens unit <NUM> is illustrated in <FIG>.

As illustrated in <FIG>, an optical system of the objective lens unit <NUM> includes a fixed lens 71A, a first movable lens 71B and a second movable lens 71C for varying magnifying power constructed as varifocal lenses, a fixed lens 71D and a third movable lens 71E for focus adjustment arranged in this order from a side of an imaging target, and the imaging device <NUM> is disposed behind the third movable lens 71E with a prism <NUM> and a cover glass <NUM> disposed thereon. A signal obtained by the imaging device <NUM> is supplied to the processor <NUM> (see <FIG>) through a circuit board <NUM> and a signal line <NUM>.

The first movable lens 71B is held by a holding frame <NUM> having an engaging hole 81a, the second movable lens 71C is held by a holding frame <NUM> having an engaging hole 83a, and the respective lenses 71B and 71C are attached on a cam shaft <NUM> in a cylindrical shape with the engaging holes 81a and 83a fit around the outer circumference of the cam shaft <NUM>. Cam pins <NUM> and <NUM> are fit respectively in the engaging holes 81a and 83a to be protruded, and the cam shaft <NUM> is provided with cam grooves 91a and 91b formed at different inclination angles against its shaft line, so that the cam pins <NUM> and <NUM> may be engaged respectively with the cam grooves 91a and 91b.

The cam shaft <NUM> is linked with one end of a linear transmission member <NUM> of a coiled coil spring or the like, and the other end of the linear transmission member <NUM> is attached on a rotation shaft of a motor not shown provided in the operation section <NUM> (see <FIG>). Accordingly, when the cam shaft <NUM> is rotated through the linear transmission member <NUM> by driving the motor, the first movable lens 71B and the second movable lens 71C are moved in the forward/backward direction along the optical axis by different distances owing to the engagement between the cam grooves 91a and 91b and the cam pins <NUM> and <NUM>, resulting in attaining optical variable power (for enlargement) or the like. In other words, the first and second movable lenses 71B and 71C together construct a varifocal optical system, so as to attain the optical variable power by relatively moving backward/forward (namely, so as to vary an observation distance, an observation depth, a focal length and the like). This structure corresponds to a variable power driving mechanism.

On the other hand, a compact and high-speed actuator <NUM> utilizing a piezoelectric element is provided on a supporting section <NUM> for driving the third movable lens 71E for focus adjustment, and the periphery of a drive shaft 95a of the actuator <NUM> is movably fit in an engaging hole 99a of a holding frame <NUM> of the third movable lens 71E. In this actuator <NUM>, the piezoelectric element is provided on the drive shaft 95a, so as to move the drive shaft 95a backward/forward at high and low speed by the piezoelectric element, thereby moving the third movable lens 71E backward/forward. This structure corresponds to a focus driving mechanism. It is noted that the actuator <NUM> may be another compact linear actuator such as an electrostatic actuator.

The optical system of the objective lens unit <NUM> is simply illustrated as a structure of a block diagram of <FIG>. Specifically, the zoom control section <NUM> controls the variable power driving mechanism <NUM> and the focus driving mechanism <NUM> of the objective lens unit <NUM> so as to set desired magnifying power and adjust the focus with the magnifying power. The magnifying power is set by operating a zoom operation section <NUM> connected to the zoom control section <NUM>. The zoom operation section <NUM> corresponds to operation buttons or slide switches arranged in the operation section <NUM> (see <FIG>) and is constructed to be able to continuously change the observation magnifying power.

In endoscopic diagnosis of, for example, the large intestine, the form and the color of the surface of the mucosa may be observed with low magnifying power and blood vessels of the surface layer may be observed with high magnifying power, and hence, a preferable color tone of the illuminating light differs depending upon the observation magnifying power. Specifically, the illuminating light is preferably white when the magnifying power is low and the illuminating light preferably includes a visible short-wavelength component in a large ratio for extracting information of the blood vessel of the surface layer when the magnifying power is high.

Therefore, as illustrated as the relationship between the observation magnifying power and the light quantity ratio in <FIG>, the color tone of the illuminating light is changed in accordance with the observation magnifying power. Specifically, an output light quantity ratio between the blue laser light source <NUM> and the violet laser light source <NUM> is controlled by the light source control section <NUM>, so as to increase the output light quantity of the violet laser light source <NUM> as the observation magnifying power set by the zoom control section <NUM> is higher. As a result, in the light quantity ratio between the profile A with the short wavelength and the profile B of the white light illustrated in <FIG>, the light quantity of the profile A is increased as the observation magnifying power is higher, so as to attain illuminating light including the short-wavelength component in a larger ratio. Since this change of the color tone is performed on a real-time basis simultaneously with the zoom operation performed by an operator of the endoscope or the like, the control may be carried out with high responsibility. It is noted that the relationship illustrated in <FIG> is not limited to the linear relationship but may be a non-linear curved relationship or a relationship changed in a stepwise manner.

At this point, <FIG> is an explanatory diagram schematically illustrating blood vessels present in a mucosal surface layer of a biological tissue. In the mucosal surface layer of the biological tissue, blood capillaries B2 such as dendritic vasoganglion are formed from blood vessels B1 of a mucosal deep layer, and it has been reported that a lesion of the biological tissue appears in a fine structure of the blood capillary B2 or the like. Therefore, an attempt is being made for early detection of a small lesion or diagnosis of a lesion area by observing a highlighted image of the blood capillaries of the mucosal surface layer.

When the illuminating light enters a biological tissue, although the incident light propagates while spreading in the biological tissue, the absorbing/scattering characteristic of the biological tissue has dependency on wavelength, and hence, the scattering characteristic tends to be higher when the wavelength is shorter. In other words, the depth of invasion of the light varies depending upon the wavelength of the illuminating light. Therefore, when the illuminating light is in a wavelength region λa in the vicinity of <NUM>, blood vessel information of the blood capillaries of the mucosal surface layer may be obtained, and when it is in a wavelength region λb in the vicinity of <NUM>, blood vessel information including blood vessels of a deeper layer may be obtained. Accordingly, for the observation of blood vessels of the surface layer of the biological tissue, a light source with a center wavelength of <NUM> through <NUM>, preferably <NUM> through <NUM> and more preferably <NUM> through <NUM> is used.

As roughly illustrated in <FIG> as display examples of an observation image obtained by the endoscopic device, in an observation image obtained by using illuminating light of white light, an image of blood vessels of a comparatively deep mucosal layer is obtained while fine blood capillaries of a mucosal surface layer are blurred. On the other hand, in an observation image obtained by using illuminating light including the visible short-wavelength component in a large ratio, fine blood capillaries of the mucosal surface layer are clear.

In other words, in observation of blood vessels of a surface layer with high observation magnifying power, the color tone of the illuminating light is controlled to increase blueness, and in observation with low observation magnifying power, the illuminating light is controlled to be white with the blueness suppressed, and thus, the illuminating light suitable to the diagnosis performed by the operator of the endoscope may be attained. In this manner, in the adjustment of the observation magnifying power, there is no need for the operator to perform a complicated operation such as adjustment of the output light quantities of the blue laser light source <NUM> and the violet laser light source <NUM> but the illuminating light with a color tone optimum to an observation site may be always automatically attained.

Furthermore, in this endoscopic device <NUM>, the change of the color tone of the illuminating light is performed by driving the light sources <NUM> and <NUM>, and therefore, as compared with a case where the color tone is changed by using a color filter or the like, the light utilization may be improved and noise caused in an observation image may be reduced. Furthermore, the color tone may be more finely adjusted.

The light sources <NUM> and <NUM> may be driven as follows:
The light source control section <NUM> of <FIG> controls the output light quantity of each of the light sources <NUM> and <NUM> in accordance with an instruction issued by the control section <NUM>. In each of the light sources <NUM> and <NUM>, there is a relationship R1 between an applied current and an emitted light quantity as illustrated in <FIG>, and hence, the applied current to each of the light sources <NUM> and <NUM> is controlled so as to attain a desired emitted light quantity. For example, in order to attain an emitted light quantity La, while securing an emitted light quantity Lb on the basis of the relationship R1 by setting the applied current to Ib, a difference ΔL between the emitted light quantities Lb and La as a fine adjustment margin is obtained by superimposing a pulse-modulated pulse current on the applied current.

As the applied current used in this case, for example, as illustrated as a pulse current superimposed waveform of the applied current in <FIG>, the emitted light quantity La is obtained by the pulse current with the applied current Ib as bias. As pulse width control of a pulse current, an arbitrary waveform may be obtained by using an appropriate PWM circuit, and the emitted light quantity may be thus accurately set. Through such bias current control and pulse-modulated control, a settable dynamic range of the emitted light quantity may be widely secured.

It is noted that any of various drive waveforms may be utilized for the pulse-modulated control performed in this case. For example, when a pulse waveform as illustrated in <FIG> repeatedly turned on/off in synchronization with optical storage time per frame of an image of an imaging device is utilized, wasteful heat generation may be avoided. Alternatively, a pulse waveform as illustrated in <FIG> with a sufficiently short cycle as compared with the optical storage time is utilized, image noise derived from speckle of laser may be reduced. Further alternatively, a pulse waveform as illustrated in <FIG> obtained by mixing the waveforms of <FIG> in which the on period of the pulse waveform of <FIG> has the pulse waveform with the short cycle of <FIG> is utilized, the aforementioned effects may be simultaneously achieved.

Furthermore, when the light sources <NUM> and <NUM> are controlled to be alternately turned on so as to alternately attain the maximum emitted light quantity as illustrated in <FIG>, the maximum driving power of the light source device <NUM> for both the light sources <NUM> and <NUM> may be suppressed, so as to reduce the burden on the body of the subject. Moreover, pickup images obtained respectively with the illuminating light of the light sources <NUM> and <NUM> may be individually obtained, and in such a case, it is possible to perform an operation between the obtained images, so as to improve the degree of freedom in the image processing.

In this manner, in accordance with the observation magnifying power, that is, one of information on an access degree between the region to be observed of the subject and the endoscope tip portion <NUM>, the ratio of the visible short wavelength component in the illuminating light is increased as the access degree is higher, so as to automatically change the color tone of the illuminating light, and thus, the illuminating light with a color tone always suitable to observation is obtained and the convenience in the operation with the endoscope is improved. Incidentally, the observation magnifying power herein means observation magnifying power on the region to be observed and is not limited to the optical magnifying power for optically changing the angle of view of an observation image by using the objective lens unit <NUM> as described above but may be digital zoom magnifying power for electrically changing the angle of view in the observation image obtained by the imaging device <NUM> (see <FIG>). When the digital zoom magnifying power is employed, the control section <NUM> instructs the output light quantity ratio between the light sources <NUM> and <NUM> to the light source control section <NUM> on the basis of information input from the input section <NUM> of <FIG>.

Furthermore, when an observation mode with different observation magnifying power is switched by operating an operation switch <NUM> provided on the operation section <NUM> of the endoscope <NUM>, the light quantity ratio may be changed in synchronization with the operation of the operation switch <NUM>.

Next, as another example of the change of the color tone of the illuminating light in accordance with the information on the access degree between the region to be observed and the endoscope tip portion <NUM>, a structure in which the color tone is changed in accordance with the quantity of light from the region to be observed on the basis of an imaging signal output from the imaging device <NUM> will be described. As illustrated in <FIG>, when the distance between the region to be observed and the endoscope tip portion is large, the quantity of light received by the imaging device <NUM> tends to be small, and when the distance is small, the quantity of the received light tends to be large. In other words, the distance between the region to be observed and the endoscope tip portion <NUM> may be estimated on the basis of the quantity of light received by the imaging device <NUM>. Therefore, a signal corresponding to the quantity of reflected light (hereinafter referred to as the A/E signal) is generated on the basis of an output signal from the imaging device <NUM>, and the output light quantity ratio between the light sources <NUM> and <NUM> is changed on the basis of the A/E signal.

Specifically, the control section <NUM> determines that the distance between the region to be observed and the endoscope tip portion is smaller and the access degree is higher as the brightness of the detected A/E signal is lower, so as to make the light source control section <NUM> increase the ratio of the output light quantity of the violet laser light source <NUM> for increasing blueness in the color tone of the illuminating light. On the contrary, as the brightness of the A/E signal is higher, the ratio of the output light quantity of the blue laser light source <NUM> is increased, so as to control the illuminating light to be white with blueness suppressed.

When this structure is employed, the output signal from the imaging device <NUM> always continuously obtained during the observation with the endoscope is used for obtaining, on the basis of the A/E signal, the quantity of the reflected light, that is, one of the information on the access degree between the region to be observed of the subject and the endoscope tip portion <NUM>, and since the distance between the region to be observed and the endoscope tip portion is thus estimated, the illuminating light may be changed to always have the optimum color tone with high responsibility.

Next, an exemplary structure in which the color tone of the illuminating light is changed in accordance with a site of the region to be observed will be described. <FIG> is a block diagram roughly illustrating the structure of an endoscopic device employing this exemplary structure. As illustrated in <FIG>, the endoscopic device <NUM> has basically the same structure as that illustrated in <FIG>, and a controller <NUM> is connected to a network <NUM> built in a hospital. Furthermore, a reception terminal <NUM>, a server <NUM>, a clinical department terminal <NUM> and the like are connected to the network <NUM>, so as to share various information with the endoscopic device <NUM>.

In this exemplary structure of the endoscopic device <NUM>, an observation site of a patient, that is, a subject, to be observed with the endoscope is extracted from test order information, and the color tone of the illuminating light is changed in accordance with information of the extracted observation site. When the color tone of the illuminating light is set to be suitable to diagnosis of the observation site, it becomes easy to find and diagnose a lesion. It is herein assumed for explanation that a patient is subjected to an endoscopic test in the hospital.

In an environment of a hospital management system such as electronic clinical recording and a test ordering system, when the patient first clears reception processing through the reception terminal <NUM> installed in the hospital, reception information is sent to the server <NUM>. The server <NUM> refers to a memory device such as a mass storage hard disc included therein for the information of the received patient, so as to extract patient information such as a patient ID, a patient name and an age of the patient having been registered, and, if a test is scheduled, test information such as a test site for the test, equipment to be used for the test and a doctor in charge as illustrated in <FIG>.

Thereafter, when test order information including the patient information and the test information is sent from the server <NUM> to the clinical department terminal <NUM> of a specific clinical department where the endoscopic test is to be carried out, the patient is subjected to the endoscopic test in this specific clinical department.

When the endoscopic device used in this test is the aforementioned endoscopic device <NUM>, the control section <NUM> of the endoscopic device <NUM> acquires the information of the test site included in the test order information at prescribed timing, and sets the illuminating light to the color tone suitable to the test site. The relationship between a test site and a color tone of the illuminating light is precedently stored in the memory section <NUM> of the endoscopic device <NUM>, and the control section <NUM> refers to the thus stored table information so as to instruct the light source control section <NUM> to attain a desired light quantity ratio between the light sources <NUM> and <NUM>.

When this structure is employed, in the case where an observation site is known prior to the test, the color tone of the illuminating light of the endoscopic device may be set optimally to, for example, the observation site of each biological organ. For example, although the same endoscope for the upper digestive tube is used in the endoscopic test, the gaster having a large number of blood vessels has a color with strong redness as compared with the esophagus. Therefore, in observation of the gaster with the endoscope, a red component is first saturated and the quantity of green and blue light tends to be lacking in a pickup image, and hence, the S/N of an observation image is degraded. In such a case, the ratio of the blue and green components of the light sources is increased, so as to obtain an image with satisfactory S/N with respect to the three colors of red, green and blue. Incidentally, when the color tone of the light source is changed, the color tone of a pickup image is corrected for color balance through image processing, so as to constantly retain colors displayed on the display section <NUM> for displaying an observation image.

Incidentally, any of various setting may be employed apart from the aforementioned setting of the test site by using the hospital management system, and for example, the endoscopic device <NUM> may be automatically changed in the color tone of the illuminating light to be optimum to an observation site by an operator of the endoscope inputting information of the test site to the endoscopic device <NUM>.

Next, an exemplary structure in which the color tone of the illuminating light is changed in accordance with the type of endoscope will be described. <FIG> is a block diagram roughly illustrating the structure of an endoscopic device employing this exemplary structure. As illustrated in <FIG>, the endoscopic device <NUM> has basically the same structure as that illustrated in <FIG>, and an endoscope <NUM> includes a main body memory section <NUM> storing individual identification information of the endoscope <NUM>. Also, a controller <NUM> is connected to a network <NUM> to which a server <NUM> and a memory device <NUM> are connected.

The main body memory section <NUM> includes an IC memory, an IC tag or the like, and a ROM such as a flash memory or a RAM may be used as the IC memory, and an RFID (Radio frequency identification) or the like may be used as the IC tag. When the IC tag is used, a reader device may be provided in a connector section 25B, so that a signal obtained by reading the IC tag may be input to a control section <NUM>.

In this exemplary structure of the endoscopic device <NUM>, the individual identification information of the endoscope <NUM> is stored in the main body memory section <NUM> included in the endoscope <NUM>, and when the endoscope <NUM> is connected to the controller <NUM> through the connector section 25B, the control section <NUM> reads the individual identification information from the main body memory section <NUM> of the endoscope <NUM>, so as to identify the connected endoscope <NUM>.

The control section <NUM> sets the color tone of the illuminating light in accordance with the individual identification information of the connected endoscope <NUM>. The relationship between individual identification information and a color tone of the illuminating light is precedently stored in a memory section <NUM> of the endoscopic device <NUM>, and the control section <NUM> refers to the thus stored table information, so as to instruct a light source control section <NUM> to attain a desired light quantity ratio between light sources <NUM> and <NUM>.

The individual identification information is, for example, the type name of the endoscope <NUM> different depending upon an applied site to be subjected to the test. <FIG> illustrates an exemplary registration table of individual identification information including the type names of endoscopes. This registration table includes individual information such as the type name, a manufacturer's serial number and an applied site of an endoscope <NUM> and information of a light quantity ratio between light sources for changing the color tone of the illuminating light. For example, with respect to an endoscope with the type name of "EC-<NUM>", an applied site for the test is the large intestine, and the light quantity ratio between light sources <NUM> and <NUM> (see <FIG>) is set to R12.

When this endoscopic device <NUM> is used, the color tone of the illuminating light may be changed to be optimally to the endoscope <NUM> in accordance with the individual identification information of the endoscope <NUM> connected to the controller <NUM>. It is noted that the registration table may include another parameter for specifying the color tone of the illuminating light instead of the light quantity ratio.

Furthermore, the individual identification information of the endoscope <NUM> may be information corresponding to a composing member of the endoscope <NUM> instead of the information corresponding to an applied site. For example, the individual identification information may be information on the type or component of an optical member used in the endoscope <NUM> such as a phosphor <NUM> (see <FIG>), optical fibers 55A and 55B, a solid-state imaging device <NUM> or an objective lens unit <NUM>.

<FIG> illustrates an exemplary registration table of individual identification information including the type and individual specificity of a phosphor used in the endoscope <NUM>. This registration table includes individual information such as the type name of an endoscope <NUM>, the manufacturer's serial number, the type and a lot number of a phosphor, and information of the light quantity ratio between light sources for changing the color tone of the illuminating light. For example, an endoscope with the type name of "EG-<NUM>" is defined by the type of phosphor of "Y-<NUM>", the lot number of "<NUM>" and the light quantity ratio of R24. Since a more detailed composition of the phosphor "Y-<NUM>" may be specified by using the lot number on the basis of information obtained in fabrication by the manufacturer, a color tone delicately changed in accordance with the composition of the phosphor may be corrected to a desired color tone. In other words, it is possible to accurately define a light quantity ratio optimum to the specified phosphor.

In this manner, the color tone of the illuminating light optimum to the endoscope <NUM> to be used may be easily set by changing the color tone of the illuminating light in accordance with the individual identification information of the endoscope <NUM>.

In each of the endoscopic devices <NUM>, <NUM> and <NUM> described so far, the illuminating light is generated by multiplexing/demultiplexing the laser beams emitted by the two laser light sources <NUM> and <NUM> and guiding the resultant light to the phosphor <NUM>, which does not limit the invention, and needless to say, another structure of the light source device may be employed. Now, other exemplary structures of the light source device will be exemplarily described.

<FIG> is a diagram roughly illustrating the structure of an endoscopic device in which one optical fiber 55A is used as an optical path from a light source device <NUM> to an endoscope <NUM>. In this structure, in the middle of an optical path where blue laser beams emitted from a blue laser light source <NUM> with a center wavelength of <NUM> is introduced into the optical fiber 55A, a dichroic prism <NUM> for merging violet laser beams emitted from a violet laser light source <NUM> with a center wavelength <NUM> is provided.

A phosphor <NUM> disposed on a light outputting side of the optical fiber 55A in this case has characteristics to absorb part of the blue laser beams emitted from the blue laser light source <NUM> for emitting green to yellow light through excitation, to generate white light by multiplexing the resultant light with part of the blue laser beams not absorbed but transmitted and to transmit the violet laser beams emitted from the violet laser light source <NUM> substantially without absorbing. Therefore, as the phosphor <NUM>, a material for emitting light through excitation under radiation of the blue laser beams with high efficiency and generating white light by multiplexing the resultant light with the blue laser beams and a material for reducing the quantity of light emitted from the phosphor under radiation of the violet laser beams are used.

Incidentally, there is a wavelength conversion loss (a Stokes loss) such as heat generation principally caused in the wavelength conversion performed by the phosphor <NUM> in general. Therefore, when an excitation wavelength with a longer emission wavelength is selected, the luminous efficacy of the phosphor is higher, which is advantageous in suppression of heat generation of the phosphor. When this structure is employed, for the aforementioned reason, the white light is generated by using the laser beams of the longer wavelength, so as to improve the luminous efficacy.

<FIG> illustrates examples of an emission spectrum of illuminating light obtained by the light source device <NUM> and the phosphor <NUM> of <FIG>. As illustrated in <FIG>, although the phosphor <NUM> is excited also under radiation of the violet laser beams, the quantity of light emitted from the phosphor <NUM> through the excitation under radiation of the violet laser beams is as small as one severalth (at least one third, preferably one fifth and more preferably one tenth or less) as compared with the quantity of light emitted through excitation under radiation of the blue laser beams. When the quantity of light emitted from the phosphor <NUM> through excitation under radiation of the violet laser beams is suppressed to this extent, the color temperature of the white light may be suitably retained.

When the aforementioned structure is employed, since the optical paths of the plurality of kinds of laser beams is combined by using the dichroic prism <NUM>, the light is guided by one optical fiber 55A from the light source device <NUM> to the phosphor <NUM> of the endoscope <NUM> and in addition, since a radiation port of the illuminating light may be provided in one portion of the phosphor <NUM>, the space efficiency may be improved so as to make a contribution to diameter reduction of an endoscope insert section.

Furthermore, also in the case where another laser light source is provided in addition to the blue laser light source <NUM> and the violet laser light source <NUM>, the optical paths may be similarly combined through optical coupling means such as a dichroic prism. Also, the phosphor <NUM> may be made of a fluorescent material that is not or minimally excited under radiation of light of the wavelength of the additional laser light source.

At this point, as a specific material for the phosphor <NUM> to be employed in the aforementioned exemplified structure, for example, a crystalline solid-state fluorescent material including lead (Pb) as an additional element and digallium calcium tetrasulfide (CaGa<NUM>S<NUM>) as a parent body as described in <CIT>, or a crystalline solid-state fluorescent material including lead (Pb) and cerium (Ce) as additional elements and digallium calcium tetrasulfide (CaGa<NUM>S<NUM>) as a parent body may be used. When such a fluorescent material is used, fluorescence covering substantially the whole visible range of approximately <NUM> through approximately <NUM> may be obtained, so as to improve color rendering in radiation with the white light.

Alternatively, a combination of a green phosphor of LiTbW<NUM>O<NUM> (see "<NPL>) or the like), a β-sialon (Eu) blue phosphor (see "<NPL>) or <NPL>)), a CaAlSiN<NUM> red phosphor and the like may be used. The β-sialon is a crystal including aluminum and an acid solid solved in a β-silicon nitride crystal and having a composition of Si<NUM>-zAl<NUM>O<NUM>N<NUM>-z (wherein z is the ratio of a solid solved component). In the phosphor <NUM>, the LiTbW<NUM>O<NUM>, the β-sialon and CaAlSiN<NUM> may be mixedly present or layers of these phosphors may be stacked.

<FIG> is a diagram roughly illustrating the structure of another endoscopic device using a large number of laser light sources. When the structure illustrated in <FIG> is employed, blue laser beams emitted from a blue laser light source <NUM> with a center wavelength of, for example, <NUM> are guided through a connector section 25A to an optical fiber 55C included in an endoscope <NUM>, so as to radiate a phosphor <NUM> disposed at a light outputting end of the optical fiber 55C. Therefore, light emitted through excitation from the phosphor <NUM> under radiation of excitation light of the blue laser beams and part of the blue laser beams transmitting the phosphor <NUM> together generate white light.

Furthermore, laser beams respectively emitted from a violet laser light source <NUM> with a center wavelength of, for example, <NUM>, a blue-green laser light source <NUM> with a center wavelength of, for example, <NUM> and a red laser light source <NUM> with a center wavelength of, for example, <NUM> are respectively introduced through the connector section 25A to optical fibers 55D, 55E and 55F, so as to give violet, blue-green and red illuminating light respectively through light deflecting/diffusing members <NUM>, <NUM> and <NUM>.

Each of the light deflecting/diffusing members <NUM>, <NUM> and <NUM> may be made of any material that may transmit incident laser beams, and for example, a resin material with a translucent property, glass or the like is used. Alternatively, each of the light deflecting/diffusing members <NUM>, <NUM> and <NUM> may be made of a resin material or glass having, on its surface, a light diffusing layer with fine irregularities or particles (fillers or the like) with different refractive indexes mixedly provided, or a semitransparent material. In this manner, transmitted light output from each of the light deflecting/diffusion members <NUM>, <NUM> and <NUM> is obtained as illuminating light of a narrowed band wavelength in which light quantity is made uniform within a prescribed radiation region.

When a large number of laser light sources with different emission wavelengths are thus used for generating the illuminating light by adjusting the light quantity ratio among the respective light sources, the range of the color tone that may be generated by a light source control section <NUM> may be increased, and the adjustment range of the color tone suitable to observation may be expanded. Furthermore, delicate adjustment of the color tone may be easily and accurately carried out.

Incidentally, it is preferable to selectively use an optimum fiber in accordance with the wavelength to be employed as each of the optical fibers 55C, 55D, 55E and 55F. The core of an optical fiber has wavelength dependency with a transmission loss changed in accordance with the level of a hydroxyl group (OH-) density, and exhibits different absorptance against a specific infrared wavelength from that against a wavelength of the visible range. Therefore, when the wavelength of the light source is not more than <NUM>, an optical fiber including a core with a high hydroxyl group density is used, and when the wavelength exceeds <NUM>, an optical fiber including a core with a low hydroxyl group density is used.

<FIG> is a diagram roughly illustrating the structure of another exemplary endoscopic device using a white light source and a laser light source. In this exemplary structure, a light source for emitting light of a broad wavelength band, such as a halogen lamp, a xenon lamp or a white light emitting diode, is used as the white light source <NUM>, so as to radiate white light from a tip portion of an endoscope <NUM> through a light guide <NUM>, that is, an optical fiber bundle. The color tone of the illuminating light is changed in accordance with the output light quantity of one or plural kinds of the laser light source <NUM>. The output light from the laser light source <NUM> is transferred through a connector section <NUM> by an optical fiber <NUM> to the endoscope tip portion so as to be emitted as illuminating light of a specific color from a light deflecting/diffusing member <NUM> disposed at the light outputting end of the optical fiber <NUM>. Alternatively, the light deflecting/diffusing member <NUM> may be replaced with a phosphor so as to emit fluorescence of a desired color as the illuminating light.

When the aforementioned structure is employed, the color tone of the illuminating light may be changed with a simple structure.

<FIG> is a diagram roughly illustrating the structure of an endoscopic device including a light emitting diode disposed in a tip portion of an endoscope <NUM>. In this exemplary structure, the light emitting diode is provided in the tip portion of the endoscope <NUM>. As the light emitting diode, for example, a blue light emitting diode <NUM>, a green light emitting diode <NUM> and a red light emitting diode <NUM> are used, so as to be individually controlled for the emitted light quantity by drivers <NUM> connected to a light control section <NUM> of a light source device <NUM>.

When this structure is employed, illuminating light of an arbitrary color tone including white may be obtained by using light emitting devices of the primary colors of light. Alternatively, a white light source <NUM> may be additionally provided for increasing the light quantity of white light so as to supply the white light to the endoscope <NUM>. As the white light source <NUM> used in this case, a halogen lamp, a xenon lamp, a white light emitting diode or the aforementioned light source obtained by combining a laser light source and a phosphor may be used.

Although the color tone of the illuminating light is controlled by adjusting the output light quantity of each light source by the light source control section <NUM> in each of the aforementioned structures of the endoscopic device, the color tone may be changed without changing the output light quantity of each light source. For example, when the respective light sources are individually turned on and exposure time of the imaging device <NUM> at on timings of each light source is changed, the color tone of the illuminating light is changed in a pseudo manner. Specifically, the respective light sources and the imaging device <NUM> are synchronously controlled, so that exposure times such as exposure time of the imaging device <NUM> for obtaining a pickup image with merely a first light source of, for example, a blue laser light source turned on and exposure time for obtaining a pickup image with merely a second light source of, for example, a white light source turned on may be individually adjusted to be increased/decreased, and the thus obtained pickup images are synthesized to give observation image data. In this observation image data, the exposure time with each light source turned on corresponds to the light quantity of the light source, and hence, the color tone of the illuminating light may be regarded to be changed in a pseudo manner. In other words, instead of directly controlling the color tone of the illuminating light in accordance with the output light quantities of the respective light sources, the color tone of the illuminating light may be indirectly changed by individually adjusting the exposure time of the imaging device <NUM> with each illuminating light by using imaging controlling means for synchronously controlling the light sources and the imaging device.

Claim 1:
An endoscopic device comprising:
an illuminating unit which emits illuminating light from an endoscopic tip portion, and includes a plurality of kinds of light sources different from one another in an emission wavelength,
an imaging unit which obtains a pickup image of a region to be observed of a subject radiated with the illuminating light,
a color tone controlling unit (<NUM>) which changes a color tone of the illuminating light by changing an output light quantity ratio among the plurality of kinds of light sources,
wherein an operation section (<NUM>) of an endoscope (<NUM>) of the endoscope device (<NUM>) includes an operation switch (<NUM>) and the light quantity ratio is changed in synchronization with the operation switch (<NUM>),
wherein the color tone controlling unit (<NUM>) drives the plurality of kinds of light sources so that two or more of the plurality of kinds of light sources emit light during an optical storage time per frame of an image of the imaging unit,
characterized in that the color tone controlling unit (<NUM>) drives the plurality of kinds of light sources by applying a current of a pulse waveform with a shorter cycle than the optical storage time per frame of an image of the imaging unit.