JPH1119026A - Endoscope apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To handily switch a normal image observation and a fluorescent image observation without thickening the tip part by bringing a polarization selecting means and a wavelength selecting means to the first state when irradiation light is switched to illumination light and to the second state when the irradiation light is switched to excitation light. SOLUTION: A polarizer 11 is disposed in proximity to the tip part of a light guide 10 for transmitting irradiation light L. A polarization selector comprising a liquid crystal element 14 for selecting polarization and an analyzer 15 and a liquid crystal color filter 16 as wavelength selection means are arranged between imaging optical systems 12 and 13 to form an image of observation light on a solid image sensor 17. The body 1 of an endoscope is provided with a changeover switch 18 to switch the states of the liquid crystal element 14 for selecting polarization and the liquid crystal color filter 16 between the operations of normal image observation and fluorescent image observation. At the operation of normal image observation, a voltage is applied to the color filter 16 but none to the liquid crystal element 14 for selecting polarization. At the operation of fluorescent image observation, a voltage is applied to the liquid crystal element 14 for selecting polarization but none to the color filter 16.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an endoscope apparatus, and more particularly to an endoscope apparatus capable of selectively switching between a normal image and a fluorescent image for observation.

[0002]

2. Description of the Related Art Conventionally, an endoscope has been widely used for observing the inside of a living body or for treating while observing the inside of a living body. When observing the inside of a living body using an endoscope, light emitted from an illumination light source arranged outside the living body is transmitted through a light guide composed of an optical fiber bundle housed in a flexible introduction tube. The light is guided into the living body to illuminate the observation unit, and the reflected light from the observation unit is received by an image sensor such as a CCD disposed at the end of the endoscope, and the output of the image sensor is displayed on a CRT or the like. It is common to display on a means, and today it is possible to obtain high-resolution images.

[0003] On the other hand, conventionally, an image based on fluorescence emitted from a living body when irradiated with excitation light or fluorescence emitted from a tumor-affinity fluorescent substance previously absorbed in a tumor portion of a living body has been observed. Research on a fluorescence image diagnostic apparatus for diagnosing a tumor part is being advanced (for example, Japanese Patent Publication No. 63-9464, Japanese Patent Application Laid-Open No. 1-136630, Japanese Patent Application Laid-Open No. 7-59783).

[0004] This kind of fluorescence image diagnostic apparatus basically includes an excitation light irradiating means for irradiating an observation section inside a living body with excitation light,
The apparatus comprises means for detecting fluorescence generated by irradiation with excitation light and capturing a fluorescence image of the observation unit, and image display means for receiving the output of the imaging means and displaying the fluorescence image. In this case, it is configured to be inserted into the body cavity and incorporated into an endoscope or the like.

[0005]

A fluorescent image diagnostic apparatus as described above is incorporated in an endoscope apparatus so that a normal image based on visible light and a fluorescent image based on fluorescent light can be displayed separately. Have been. Conventionally, as this type of device,
It is known that a sharp cut filter is inserted on a light receiving optical path when observing a fluorescent image so that light having an excitation light wavelength is blocked so that only a fluorescent image can be viewed.

However, in the case of an electronic endoscope apparatus having an image pickup device at the distal end of the endoscope, a filter must be provided in front of the image pickup device, and a filter for moving the filter is required. Space is required and the tip becomes thick. The tip of the endoscope should be as thin as possible to be inserted into the subject.

Japanese Utility Model Laid-Open No. 3-43086 proposes an endoscope apparatus having a configuration in which the specular reflection light of excitation light and the fluorescence generated from an observation visual field (living body) are separated using polarized light to obtain a fluorescent image. I have. In the endoscope device, the liquid crystal polarizing means whose optical rotation state changes according to the voltage application state is cut off by using a liquid crystal polarizing means, and there is no movable part at the end portion of the endoscope, so that the end portion can be made thin. .

However, fluorescence is generally weaker than excitation light, so that even if specular reflection light of excitation light is removed, it is strongly affected by diffuse reflection light, and a clear fluorescent image may not be obtained.

The present invention has been made in view of the above circumstances, and can easily switch between normal image observation and fluorescent image observation without enlarging the tip, and obtain a clear fluorescent image. It is an object of the present invention to provide an endoscope apparatus capable of performing the above-described operations.

[0010]

An endoscope according to the present invention includes a light source device for selectively emitting one of illumination light and excitation light as irradiation light, irradiating the irradiation light to a living body, and irradiating the living body with the irradiation light. In an endoscope apparatus which receives observation light which is reflected light or fluorescence and observes a normal image or a fluorescence image, the endoscope device is interposed on the optical path of the irradiation light, and the irradiation light is either P-polarized light or S-polarized light. An irradiating light polarizing means for polarizing the light into the polarized light, a first liquid crystal element and an analyzer interposed on a light receiving path of the observation light, and a polarization state of the same kind as the predetermined polarization in the observation light. In the first state, which passes light incident thereon, and the second state, in which light that enters in the same type of polarization as the predetermined polarized light is shielded, and light that enters in a different polarization state from the predetermined polarization passes. Polarization selecting means set to one of the states The state of the means, the first state when the irradiation light is the illumination light, the polarization selection means switching means to the second state when the irradiation light is the excitation light, of the observation light, A first state in which light in a wavelength range required for observation of a normal image passes, and a second state in which light in the wavelength range of the excitation light is blocked and light in the wavelength range of the fluorescence passes. Wavelength selecting means comprising a second liquid crystal element set to any one of the states, and setting the state of the wavelength selecting means to the first state when the irradiation light is illumination light; And a wavelength selecting means switching means for setting the state to the second state when.

The "irradiation light polarizing means" is, for example, P
Polarizer, S polarizer, or any linear polarizer and 1
/ 2λ plate.

[0012] The phrase "pass light incident in the same kind of polarization state as the predetermined polarized light" means, for example, that when the predetermined polarized light is P-polarized light, the P-polarized light incident on the polarization selecting means is transmitted. The light may be passed as it is, or may be polarized as S-polarized light.

In the endoscope apparatus, specifically, the first liquid crystal element and the second liquid crystal element are set according to an applied voltage. The wavelength selection unit switching unit is a unit that controls a voltage applied to the first and second liquid crystal elements, and the polarization selection unit and the wavelength selection unit when the irradiation light is set to illumination light. Are set to the respective first states, and when the irradiation light is set to the excitation light, the polarization selecting means and the wavelength selecting means are both controlled to be in the second state.

[0014] The polarization selecting means switching means may also serve as the wavelength selecting means switching means.

Further, the first liquid crystal element and the second liquid crystal element may be formed integrally. in this case,
Specifically, the liquid crystal element includes a dichroic dye having anisotropy in the short axis / long axis with respect to light absorption, and the first state of the polarization selection unit and the first state of the wavelength selection unit. Those which can achieve the state simultaneously and achieve the second state of both means simultaneously are used.

It is to be noted that, as the polarization selecting means and the wavelength selecting means, means other than liquid crystal, which can switch the state electronically or electrically, may be used.

[0017]

According to the endoscope apparatus of the present invention, since the liquid crystal polarization selecting means and the wavelength selecting means are provided as means for blocking the excitation light, the polarization and the wavelength range of the excitation light are used. As a result, the reflected light of the excitation light can be sufficiently blocked during the observation of the fluorescent image, and a highly reliable fluorescent image which is not affected by the reflected light can be obtained.

Since the state can be easily switched only by controlling the voltage by using the liquid crystal, a space is not required as compared with the conventional case where the sharp cut filter or the like is moved to cut off the excitation light. Therefore, the electronic endoscope apparatus can be used without making the distal end portion thick.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an electronic endoscope apparatus according to an embodiment of the present invention. The present endoscope apparatus 1 includes an endoscope main body 2, a light source device 3 that supplies excitation light or illumination light to the endoscope main body 2, and a distal end portion of the endoscope main body 2 inserted into a living body 4. And a monitor 6 for displaying an image signal output from the video signal circuit 5.

The light source device 3 includes a light source 20 and an excitation light filter 21 for restricting irradiation light to an excitation light wavelength region when observing a fluorescent image.
And the light emitted from the light source 20 is used as a light guide for the endoscope body 2.
It is composed of a lens 22 that condenses the light to 10. In the normal image observation, the excitation light filter 21 is located outside the irradiation light path as shown in A in the figure, and the normal illumination light is emitted from the light source device 3 as the irradiation light L, while the excitation light filter is observed in the fluorescence image observation. The filter for use 21 is inserted on the irradiation light path as shown in B in the figure, and excitation light is emitted from the light source device 3 as irradiation light L.

In the endoscope body 2, irradiation light L (illumination light Li or excitation light Le) applied to an observation site of the living body 4 is provided.
) For transmitting light, and the light guide 1
A polarizer 11, which is an emitted light polarizing means, disposed close to the tip of the imaging device 0, imaging optical systems 12, 13 for imaging observation light (reflected light Lr or fluorescence Lf) from the living body 4, and the imaging optical system 12,1
3, a liquid crystal color filter 16 which is a polarization selecting device and a wavelength selecting means comprising a polarization selecting liquid crystal element 14 and an analyzer 15 disposed between the liquid crystal element 14 and a solid-state imaging device such as a CCD on which observation light is imaged.
17 are provided.

In the present embodiment, the polarizer 11 uses the living body 4 as a reflecting surface and forms a vibrating surface parallel to a surface (incident surface) containing the incident light L on the reflecting surface and the reflected light Lr on the reflecting surface. It is a linear polarizer (P-polarizer) that generates linearly polarized light (P-polarized light). Therefore, the living body 4 is transmitted through the polarizer 11.
Is P-polarized light.

FIG. 2 shows the polarization selecting liquid crystal element 14 shown in FIG.
Only the analyzer 15 and the liquid crystal color filter 16 are extracted and schematically shown.

In the polarization selecting device of this embodiment, the polarization selecting liquid crystal element 14 is composed of a TN liquid crystal cell 14a sandwiched between transparent electrodes 19, and the analyzer 15 transmits S-polarized light. The TN liquid crystal cell has optical rotation in a state where no voltage is applied, and the incident polarized light is emitted with its polarization plane rotated by 90 °. On the other hand, when a voltage is applied, the optical rotatory power is lost, and the incident light exits as it is. Therefore, the observation light including the specular reflection light which is the P-polarized light is
The first state in which only the light that has been rotated and turned into S-polarized light by 90 ° out of the observation light is selected by the analyzer 15 and passed therethrough, and the observation light is passed through the liquid crystal element 14 without being rotated, and The photon 15 can be set to one of the second state in which only the S-polarized light of the observation light is selected and passed by controlling the voltage. The switching of the state of the polarization selecting means means the switching of the state of the liquid crystal element 14, and the switching of the state of the liquid crystal element 14 is performed by controlling the voltage applied to the liquid crystal and changing the optical rotation state as described above. Done.

The liquid crystal color filter 16 has a first state in which light in a wavelength range (here, all light) required for normal image observation is transmitted, a light in an excitation light wavelength range, and a fluorescent light. Which can be set to any one of the second state and the second state in which light in the wavelength range is transmitted. Specifically, a liquid crystal cell in which a dye molecule 16b is mixed in a nematic liquid crystal 16a is sandwiched between transparent electrodes 19 is used. When the dye (guest molecule) 16b is mixed with the nematic liquid crystal (host molecule) 16a, the property that the long axis of the dye molecule 16b is arranged in the same direction as the long axis of the liquid crystal molecule 16a is used. Here, a dichroic dye whose light absorption in the major axis direction is near the excitation light wavelength and whose light absorption in the minor axis direction is very small is used as the dye molecule 16b. As the nematic liquid crystal, which is the host molecule 16a, a liquid crystal whose major axis is arranged in a direction parallel to the electrodes when no voltage is applied and whose major axis is arranged in a direction perpendicular to the electrodes when voltage is applied is used. The switching of the state of the liquid crystal color filter 16 is performed by controlling the voltage applied to the liquid crystal and changing the arrangement of the liquid crystal molecules, as in the case of the polarization selection liquid crystal element 14.

The endoscope main body 2 is provided with an applied voltage control means which is a changeover switch 18 for switching the state of the polarization selecting liquid crystal element 14 and the liquid crystal color filter 16 during normal image observation and fluorescence image observation. And color filters 16
The applied voltage control circuit includes an inverter (not shown). Switch 18 is OFF during normal image observation
In this state, no voltage is applied to the polarization selecting liquid crystal element 14, while the color filter 16
Is applied with a voltage. At this time, the polarization selection liquid crystal element
14 and the color filter 16 are each in the first state. At the time of fluorescence observation, the changeover switch 18 is turned ON, and a voltage is applied to the polarization selecting liquid crystal element 14, while no voltage is applied to the color filter 16 by the action of the inverter described above. At this time, the polarization selecting liquid crystal element 14 and the color filter
16 are each set to the second state.

The absorption / fluorescence spectrum of a general fluorescent agent is shown in FIG. 3 (a), and the wavelength range of light absorbed by the fluorescent agent is greater than the wavelength range of fluorescence emitted from the fluorescent agent. And the overlapping range of both wavelength ranges is small. Therefore, in order to generate fluorescence from the fluorescent agent, light in the absorption wavelength region of the fluorescent agent may be used as the excitation light, and a filter having the transmission characteristics shown in FIG. The liquid crystal color filter 16 transmits light over almost the entire wavelength range in the first state (dotted line) of the voltage application and in the second state (solid line) of no voltage application as shown in FIG. A filter that blocks light near the excitation light wavelength region and transmits light in the fluorescence wavelength region is used. As described above, the liquid crystal color filter shows absorption in the short axis direction when the voltage is applied, because the long axes of the dye molecules are arranged in the direction perpendicular to the electrodes, but the absorption in the short axis direction is the same. Since the light is very small as shown in FIG. 3C, the light incident on the liquid crystal color filter 16 passes through the liquid crystal color filter 16 almost as it is. On the other hand, when no voltage is applied, the major axes of the dye molecules are arranged in a direction parallel to the electrodes, so that absorption occurs in the major axis direction, and light near the excitation light region is absorbed.

Specifically, Photofrin II, which is used for treating and diagnosing cancer, is administered as a fluorescent agent.
6 to excite an absorption band called a Q band near nm.
Light in a wavelength range around 30 nm is used as excitation light. At this time, fluorescence having a peak near 690 nm emitted from the fluorescent agent is detected. As the dye molecules of the liquid crystal color filter 16, for example, the following dye molecules having a property of absorbing light in the excitation light wavelength range are used.

[0029]

Embedded image

Here, the M1 direction is the major axis direction, and M
Two directions are short axis directions. The maximum absorption wavelength λmax1 in the major axis direction of the dye molecule is 635 nm, and the maximum absorption wavelength λmax2 in the minor axis direction is 415 nm.

The operation of the electronic endoscope apparatus 1 during normal image observation and fluorescence image observation will be described below.

1) At the time of normal image observation (changeover switch OFF state) At the time of normal image observation, the excitation light filter
Reference numeral 21 is located at the position A, and the changeover switch 18 in the endoscope main body 2 is turned off. Accordingly, the polarization selecting liquid crystal element 14 is in a state (first state) in which observation light including P-polarized specular reflection light is rotated by 90 ° and passed therethrough, and the liquid crystal color filter 16 is in a state in which light in the entire wavelength range is passed ( (First state).

The irradiation light from the light source 20 is illumination light Li,
As shown in FIG. 4, the illumination light Li is focused on the light guide 10 by the lens 22. The illumination light Li passes through the light guide 10, is converted into P-polarized light by the P polarizer 11, and is emitted from the end of the endoscope.
Is irradiated.

The illumination light Li (P) is reflected by the living body 4 and is incident as reflected light Lr from the end of the endoscope 2. The incident light is rotated by 90 ° in the polarization-selecting liquid crystal element 14, and of the observation light, only the light that has been rotated and turned into S-polarized light passes through the analyzer 15, and
And is imaged on the CCD 17. The video signal from the CCD 17 is input to the monitor 6 after being processed by the video signal circuit 5, and a normal image is displayed on the monitor 6.

When normal image observation is performed on a living body to which a fluorescent diagnostic agent has been previously administered, fluorescence Lf is generated from the living body due to the excitation light wavelength included in the illumination light Li (P).
Since the fluorescence is weaker than the reflected light Lr, it has almost no effect when observing a normal image.

2) At the time of observing the fluorescent image (ON state of the changeover switch) In order to observe the fluorescent image, a fluorescent diagnostic agent (fluorescent agent) such as HpD or Photofrin II having tumor affinity is administered to the subject in advance. .

At the time of fluorescence observation, the excitation light filter 21 is inserted at the position B on the emission optical path in the light source device 3, and the changeover switch 18 in the endoscope main body 2 is turned on. Accordingly, the polarization selecting liquid crystal element 14 is in a state in which the observation light is passed without rotation, that is, in a state in which only the S-polarized light of the observation light is transmitted through the analyzer 15 (second state), and the liquid crystal color filter 16 is turned on. Is set to a state (second state) in which light in the wavelength range of the excitation light is blocked and light in the wavelength range of the fluorescence is transmitted.

As shown in FIG. 5, of the light emitted from the light source 20, only light in the wavelength region that generates fluorescence (excitation light) passes through the excitation light filter 21 and is converted into the excitation light Le by the lens 22 as excitation light Le. Is condensed. The excitation light Le
Is converted into P-polarized light by a P-polarizer 11 through a light guide 10, emitted from the end of the endoscope, and excited by P-polarized excitation light Le (P).
Is irradiated on the living body 4.

When the excitation light Le (P) is irradiated, the fluorescent agent taken into the tumor part 4a of the living body 4 generates fluorescence Lf.
On the other hand, a part of the excitation light Le (P) is reflected by the living body 4, and the reflected light Lr including the regular reflected light Lr1 and the diffuse reflected light Lr2 is converted into the fluorescent light Lf.
At the same time, the light enters from the end of the endoscope 2. The incident light further enters the polarization selecting liquid crystal element 14 and passes through the liquid crystal element 14 as it is. Thereafter, only the S-polarized wave of the observation light is selectively transmitted to the liquid crystal color filter 16 by the analyzer 15. Is done. That is, the specular reflection component Lr1 of the P-polarized excitation light
Is blocked by the analyzer 15, and the S-polarized light component L of the fluorescence Lf is
f (S) and a part of the diffuse reflection component Lr2 of the excitation light (S-polarized diffuse reflection light component) Lr2 (S) pass through the analyzer 15. Analyzer
The light Lf (S) and Lr2 (S) that have passed through 15 are further incident on a liquid crystal color filter 16, which emits excitation light Le.
Is set so as to block the light in the wavelength range of and the light in the wavelength range of the fluorescent light, so that the S-polarized diffuse reflection component Lr2 (S) of the excitation light is blocked by the liquid crystal filter 15,
Only the S-polarized fluorescence Lf (S) passes through the liquid crystal color filter 16.

In this manner, the action of the polarization selecting liquid crystal element 14, the analyzer 15, and the liquid crystal color filter 16 causes the fluorescence Lf (S)
Only the image is formed on the CCD 17. Fluorescence Lf from CCD 17
A video signal reflecting (S) is output. The video signal is processed by the video signal circuit 5 and then input to the monitor 6, where a fluorescent image is displayed. As described above, it is possible to obtain a high-resolution fluorescent image in which the influence of the reflected light Lr of the excitation light Le is reduced.

In the above embodiment, when an S-polarizer is used as the irradiation light polarizing means, an analyzer that transmits P-polarized light may be used as the analyzer.

Also, contrary to the above embodiment, fluorescence observation may be performed with the changeover switch OFF and normal observation may be performed with the changeover switch ON. In this case, when a P polarizer is used as the irradiation light polarizing means, a P analyzer may be used as an analyzer, and when an S polarizer is used, a P analyzer may be used. Further, a λλ plate may be provided in the illumination (excitation) light emission part and the observation light incidence part of the endoscope tip.

Further, a 1/4 λ plate is provided in the irradiation light emitting section and the observation light incidence section, and the living (4) is irradiated with the illumination (excitation) light linearly polarized by the irradiation light polarizing means and converted into circularly polarized light. The light may be converted into linearly polarized light again at the observation light incident portion.

A liquid crystal is mixed with a dichroic dye having anisotropy in the short axis / long axis with respect to light absorption, and a voltage is applied to the liquid crystal to control the polarization plane and to block the excitation light. And the polarization selecting means and the wavelength selecting means may be formed from one liquid crystal element.

For example, the polarization selecting liquid crystal element 14 shown in FIG.
And in place of the liquid crystal color filter 16 as shown in FIG.
A liquid crystal element 31 is used in which a liquid crystal cell in which a dichroic dye molecule 31b is mixed with a TN liquid crystal 31a is sandwiched between a pair of transparent electrodes 19. A switch 18 for switching the applied voltage is connected to the transparent electrode 19.

Here, as a dichroic dye, the light absorption wavelength in the short axis direction substantially coincides with the excitation light wavelength, and the light absorption wavelength in the long axis direction is other than the visible wavelength (infrared) or in the visible wavelength range. Use the one that is missing. The major axis of the dichroic dye 31b is arranged in the same direction as the major axis of the liquid crystal molecules. For example, the following dye molecules are used.

[0047]

Embedded image

In the above dye molecules, the maximum absorption wavelength λmax1 in the major axis direction is 683 nm, and the maximum absorption wavelength λmax2 in the minor axis direction is 393 nm. At this time, Photofrin II used for the treatment and diagnosis of cancer was administered as a fluorescent agent, and light in a wavelength range around 400 nm was excited to excite a strong absorption band called the Soret band around 400 nm. It shall be used as excitation light.

During normal image observation (changeover switch OFF state), the TN liquid crystal molecules 31a of the liquid crystal element 31 are twisted by 90 ° between one electrode and the other electrode.
The observation light incident on the liquid crystal cell 31 has its polarization plane rotated by 90 °. On the other hand, the dye molecule 31b has a major axis in a direction parallel to the transparent electrode 19 and exhibits absorption in the major axis direction with respect to incident light, but does not attenuate visible light because its absorption wavelength is in the infrared. Only S-polarized light of the observation light that has been rotated from the polarization plane and emitted from the liquid crystal element 31 passes through the analyzer 15. That is, the specularly reflected light Lr (P) of the P-polarized illumination light Li in the living body 4 is rotated by the liquid crystal element 31 to become S-polarized light Lr (S), passes through the analyzer 15, and forms an image on the CCD. As a result, an observation image is usually obtained.

When observing the fluorescent image (ON state of the changeover switch), the optical rotation of the liquid crystal element 31 is lost, and the polarization plane of the observation light does not rotate. On the other hand, the long axis of the dye molecule 31b is a transparent electrode.
It is perpendicular to 19 and absorbs incident light in the short axis direction to absorb light in the wavelength range of the excitation light. That is, light other than light in the wavelength range of the excitation light of the observation light transmits through the liquid crystal element 31. Only the S-polarized light of the observation light transmitted through the liquid crystal cell passes through the analyzer and is imaged on the CCD 17. Therefore, the reflected lights Lr1 and Lr2 of the excitation light Le (P) are absorbed and attenuated by the dye molecules 31b in the liquid crystal element 31, and the regular reflected light Lr1 (P), which is the main component of the reflected light, is
Transmits somewhat through the liquid crystal element 31, but is blocked by the analyzer 15. As a result, similarly to the above embodiment, the fluorescence Lf
Only (S) is imaged on the CCD 17 and the reflected light Lr of the excitation light Le
And a high-resolution fluorescent image in which the influence of is reduced.

As shown in FIG. 7, a liquid crystal color filter
A liquid crystal cell in which 32 liquid crystal cells composed of 32 nematic liquid crystal molecules 32a and dye molecules 32b are overlapped with a liquid crystal cell composed of TN liquid crystal 33a of the polarization selection liquid crystal element 33 and transparent electrodes 19 are provided at both ends thereof may be used. Good. The arrangements of the liquid crystal color filter 32 and the polarization selection liquid crystal element 33 are interchangeable.

It should be noted that a combination of liquid crystal, dye molecules, and the like can be used to perform normal image observation with a voltage applied and fluorescence image observation with no voltage applied.

Furthermore, in the above embodiment, the liquid crystal element is used as the polarization selecting means and the wavelength selecting means. However, both selecting means may be any means which can switch the state electronically / electrically. Any means may be used.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of an electronic endoscope apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram schematically showing a part of the electronic endoscope apparatus shown in FIG.

FIG. 3 is a diagram showing an absorption / fluorescence spectrum of a fluorescent agent and a spectral characteristic of each filter.

FIG. 4 is an electronic endoscope apparatus for observing a fluorescent image according to the embodiment;

FIG. 5 is an electronic endoscope apparatus during normal image observation according to the embodiment;

FIG. 6 is a diagram showing an integrated polarization selecting liquid crystal element and a liquid crystal color filter.

FIG. 7 is a diagram showing a modified example of an integrated polarization selecting liquid crystal element and a liquid crystal color filter.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electronic endoscope apparatus 2 Endoscope 3 Light source device 4 Living body 4a Tumor part 5 Video signal circuit 6 Monitor 7 Irradiation light 8 Reflected light 9 Fluorescence 10 Light guide 11 P polarizer 12, 13 Imaging optical system 14 Polarization selection liquid crystal Element 15 Analyzer 16 Liquid crystal color filter 17 CCD 18 Changeover switch 19 Electrode 20 Light source 21 Excitation light filter 22 Condenser lens

Claims (6)

[Claims] 1. A light source device that selectively emits one of illumination light and excitation light as irradiation light, irradiates the irradiation light to a living body, and receives reflected light or fluorescence observation light generated by the irradiation. In the endoscope apparatus for observing a normal image or a fluorescent image, the irradiation light is interposed on an optical path of the irradiation light, and the irradiation light is P-polarized light, S
Irradiation light polarizing means for polarizing to any predetermined polarization of polarized light, comprising a first liquid crystal element and an analyzer interposed on a light receiving path of the observation light, and the predetermined polarization of the observation light The first state of passing light incident in the same type of polarization state, and shields light incident in the same type of polarization state as the predetermined polarization,
And a polarization selecting unit that is set to one of a predetermined state and a second state in which light that has entered in a different polarization state passes therethrough; and the irradiation light illuminates the state of the polarization selecting unit. When the light is the first state, and when the irradiation light is the excitation light, the second state is changed to the polarization selection means switching means, of the observation light, the wavelength required for observation of the normal image The second state is set to one of a first state in which the light in the wavelength range of the excitation light is blocked, and a second state in which the light in the wavelength range of the fluorescence is blocked. Wavelength selecting means comprising a liquid crystal element of the following, the state of the wavelength selecting means, the first state when the irradiation light is illumination light, the second state when the irradiation light is excitation light wavelength An endoscope apparatus comprising: a selection unit switching unit. 2. The polarization selection means according to claim 1, wherein said polarization selection means and said second liquid crystal element are selectively set to said first and second states, respectively, according to an applied voltage. Means and the wavelength selection means switching means are means for controlling an applied voltage to the first and second liquid crystal elements, and when the irradiation light is set to illumination light, the polarization selection means and the wavelength The selection means are both in the first state, and when the irradiation light is set to the excitation light, the polarization selection means and the wavelength selection means are controlled to be in the second state. The endoscope apparatus according to claim 1, 3. The endoscope apparatus according to claim 2, wherein said polarization selecting means switching means also serves as said wavelength selecting means switching means. 4. The endoscope apparatus according to claim 2, wherein the first liquid crystal element and the second liquid crystal element are integrated. 5. The liquid crystal device according to claim 1, wherein said liquid crystal element has a short axis /
Including a dichroic dye having anisotropy in the major axis, simultaneously achieving the first state of the polarization selecting means and the first state of the wavelength selecting means, and simultaneously achieving the second state of both means The endoscope apparatus according to claim 4, wherein the endoscope apparatus is capable of performing an operation. 6. A light source device for selectively emitting one of illumination light and excitation light as irradiation light, and irradiating the irradiation light to a living body to receive observation light that is reflected light or fluorescence generated by the irradiation. In the endoscope apparatus for observing a normal image or a fluorescent image, the irradiation light is interposed on an optical path of the irradiation light, and the irradiation light is P-polarized light, S
Irradiation light polarization means for polarizing to any predetermined polarization of polarized light, the first state of passing light incident in the same type of polarization state as the predetermined polarization of the observation light, the same as the predetermined polarization Polarized light that blocks light that has entered in a different polarization state and that is electronically or electrically switched to one of a second state in which the predetermined polarization and light that has entered in a different polarization state pass. Selection means, the state of the polarization selection means, the first state when the irradiation light is illumination light, the polarization selection means switching means to the second state when the irradiation light is excitation light, Of the observation light, the first state in which light in the wavelength range required for observation of the normal image is transmitted, and the light in the wavelength range of the excitation light is blocked, and the light in the wavelength range of the fluorescence is Electronic or electrical to either state with the passing second state Wavelength selecting means that switches to the first state when the irradiation light is illumination light and the second state when the excitation light is illumination light. An endoscope apparatus comprising: a switching unit.