JP2017074177A - Different wavelength light selection device and endoscopic device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a different wavelength light selection device that contributes miniaturization of the device and absolute elimination of vibration and noise as well as improvement of durability.SOLUTION: A different wavelength light selection device (107) is continuously arranged with a front stage selection unit (118) for polarizing first wavelength light and configured by sandwiching a first liquid crystal panel (122) between two polarizers (120, 121) through which second wavelength light of the wavelength longer than that of the first wavelength light passes, and a rear stage selection unit (119) for polarizing the second wavelength light and configured by sandwiching a second liquid crystal panel (125) between two polarizers (123, 124) through which the first wavelength light passes. Furthermore, control means (110) for controlling a combination of ON/OFF of the first liquid crystal panel and the second liquid crystal panel is included.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a different wavelength light selection device for selecting different wavelength light (for example, visible light and infrared light) and an endoscope apparatus using the same.

  Endoscopes that capture and image the affected area of the body can only capture a planar image and cannot distinguish the unevenness of the affected area. An apparatus has been put into practical use (for example, Patent Document 1 below).

  FIG. 11 is a conceptual configuration diagram of the endoscope apparatus described in Patent Document 1. In this figure, an endoscope apparatus 1 includes a main body 2, a cylindrical guide body 4 having a flexible and predetermined length, with one end face 3 attached to an arbitrary surface of the main body 2, and the main body 2. Are provided with a first display unit 5 for displaying a planar image output from the main body unit 2 and a second display unit 6 for displaying a stereoscopic image output from the main body unit 2.

  The main body 2 includes a light source 7 that emits light including at least light in the visible region and light in the infrared region (hereinafter, white light P1), light of a different wavelength from the white light P1, in this case, light in the visible region ( Hereinafter, a rotary filter 8 that selectively extracts visible light P2) and infrared light (hereinafter referred to as infrared light P3), a drive source 9 such as a motor that rotationally drives the rotary filter 8, a planar image, And an image processing unit 10 that generates and outputs a stereoscopic image.

  The guide body 4 includes a solid cylindrical light guide 11 having flexibility such as an optical fiber arranged coaxially with its axis, and one end face on the right side of the light guide 11 in the figure. 12, light extracted from the rotary filter 8 (visible light P2 and infrared light P3) is incident thereon.

  The other end face 13 of the light guide 11 is exposed from the other end face 14 of the guide body 4, and a visible light image (hereinafter, visible image) is taken on the other end face 14 of the guide body 4. A first imaging unit 15 and a second imaging unit 16 that captures an infrared light image (hereinafter referred to as an infrared image) are provided.

  The image processing unit 10 provided inside the main body unit 2 captures captured images (visible image and infrared image) from these two image capturing units (the first image capturing unit 15 and the second image capturing unit 16). From the image, an image (planar image and stereoscopic image) to be displayed on the first display unit 5 and the second display unit 6 is generated and output.

Japanese Patent Laid-Open No. 5-56918

  However, the endoscope apparatus described in Patent Document 1 uses mechanical means (rotary filter 8 that is rotationally driven by a drive source 9 such as a motor) to select different wavelength light (visible light P2 and infrared light P3). Therefore, there is a problem that an increase in the size of the apparatus is unavoidable, a problem of vibration and noise, and a problem of durability associated with wear of the rotating part.

  Accordingly, an object of the present invention is to provide a different wavelength light selection device that contributes to miniaturization of the device, elimination of vibration and noise, and improvement of durability, and an endoscope device using the same.

  The different wavelength light selection device according to the present invention is configured by sandwiching one liquid crystal panel between two polarizing plates that polarize one wavelength light and transmit two wavelength light longer than the one wavelength light. The former stage selection unit and the rear stage selection unit configured by sandwiching two liquid crystal panels between two polarizing plates that polarize the second wavelength light and transmit the one wavelength light, are continuously arranged, The liquid crystal display device further includes a control unit that controls a combination of ON and OFF of the one liquid crystal panel and the second liquid crystal panel.

  According to the present invention, since different wavelength light can be selected without using mechanical means, the different wavelength light selection device contributing to downsizing of the device, elimination of vibration and noise, and improvement of durability, and An endoscope apparatus using the same can be provided.

It is a conceptual lineblock diagram of an endoscope apparatus concerning an embodiment. 3 is a configuration diagram of a light selection unit 107. FIG. 2 is a configuration diagram of a front-stage liquid crystal panel 122 and a rear-stage liquid crystal panel 125. FIG. 2 is a schematic diagram of a front-stage liquid crystal panel 122 and a rear-stage liquid crystal panel 125. FIG. 3 is a schematic diagram of a light selection unit 107. FIG. It is a transmission and reflection characteristic figure of a polarizing plate. FIG. 10B is a diagram (1/2) illustrating four operation modes of the light selection unit 107; FIG. 6B is a diagram (2/2) illustrating four operation modes of the light selection unit 107. It is a figure which shows the operation | movement flow of the endoscope apparatus. It is a figure which shows an operation mode table. 1 is a conceptual configuration diagram of an endoscope apparatus described in Patent Literature 1. FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings, taking application to an endoscope apparatus as an example.

  FIG. 1 is a conceptual configuration diagram of an endoscope apparatus according to the embodiment. The endoscopic device 100 includes at least a first display unit 101 for displaying a planar image, a second display unit 102 for displaying a stereoscopic image, and a main body unit 103 that stores each unit of the endoscopic device 100. And a guide body 104.

  In addition, in this figure, although two independent display parts (the 1st display part 101 and the 2nd display part 102) are shown, it is not restricted to this aspect, ie, the aspect which uses two display apparatuses. For example, in a mode in which the display screen of one display device is divided into two or a plurality of display areas, one display area is used as the first display unit 101, and two display areas are used as the second display unit 102. There may be.

  The main body unit 103 includes an image processing unit 105 that generates a planar image and a stereoscopic image, an imaging unit 106, a light selection unit 107, a first light source 108 that emits visible light P2, and a first light source that emits infrared light P3. The apparatus includes a two light source 109 and a control unit 110 that controls the operation of each unit (such as the image processing unit 105, the imaging unit 106, and the light selection unit 107), and further includes a power source unit (not shown).

  Note that the visible light P2 is light in the visible region, for example, light having a wavelength of about 400 nm to about 700 nm. The infrared light P3 is light in the infrared region, for example, light having a wavelength of about 700 nm to about 850 nm. The visible light P2 and the infrared light P3 are light having different wavelengths, that is, different wavelength light, the visible light P2 corresponds to one wavelength light, and the infrared light P3 has a longer wavelength than the one wavelength light. Corresponds to wavelength light.

  The first light source 108 is, for example, a light emitting diode such as an LED (Light Emitting Diode), and the second light source 109 is, for example, an infrared light emitting diode. Generally, these light emitting diodes emit light (referred to as non-polarized light) whose electric and magnetic fields are oscillating in all directions, so that the visible light P2 and the infrared light P3 are non-polarized light.

  The imaging unit 106 has imaging characteristics for at least a wide range of light from visible light to infrared light, such as a CCD (Charge Coupled Device) image sensor, a CMOS (Complementary Metal Oxide semiconductor) image sensor, or other methods. It is a two-dimensional imaging device.

  The imaging unit 106 outputs a visible image to the image processing unit 105 when an image of visible light is formed on the imaging surface 106a, while an image is displayed when an image of infrared light is formed. An infrared image is output to the processing unit 105. Although not shown in this figure, the imaging unit 106 has an optical system such as an imaging lens on the imaging surface 106a.

  The guide body 104 is a cylindrical solid member having a predetermined length and having a predetermined length with one end surface 111 attached to an arbitrary surface of the main body 103, and the other end surface from the one end surface 111 inside the guide body 104. 112, at least three light guides (hereinafter, first light guide 113, second light guide 114, and third light guide 115) are internally provided.

  These three light guides (first light guide 113, second light guide 114, and third light guide 115) are all flexible and guide light from end to end with low loss. For example, an optical fiber.

  The first light guide 113 guides the visible light P2 from the first light source 108 to the other end surface 112 of the guide body 104, and the second light guide 114 transmits the infrared light P3 from the second light source 109 to the guide body. It leads to the other end surface 112 of 104. Further, the third light guide body 115 reflects reflected light P4 (visible light P2 and infrared light P3) from an observation target (not shown) (not shown) facing the other end surface 112 of the guide body 104 in the vicinity. Reflected light) is guided to the incident surface 116 of the light selector 107.

  The light selection unit 107 corresponds to a “different wavelength light selection device”. The light selection unit 107 will be described in detail later, but in short, in accordance with the control from the control unit 110, different wavelength light (here, visible light and infrared light) from the reflected light P4 guided by the third light guide 115. Then, the selected light (hereinafter, selected light P5) is irradiated from the emission surface 117 to the imaging surface 106a of the imaging unit 106.

  FIG. 2 is a configuration diagram of the light selection unit 107. As shown in this figure, the light selection unit 107 has a two-stage configuration in which a rear stage selection unit 119 is continuously arranged after a front stage selection unit 118.

  The front stage selection unit 118 sandwiches one liquid crystal panel (the front stage liquid crystal panel 122) between two polarizing plates (the first polarizing plate 120 and the second polarizing plate 121), and the rear stage selection unit 119 also includes two A single liquid crystal panel (second-stage liquid crystal panel 125) is sandwiched between the single polarizing plates (first polarizing plate 123 and second polarizing plate 124).

  Here, the direction closer to the incident surface 116 of the light selection unit 107 is referred to as “front”, and the direction closer to the emission surface 117 of the light selection unit 107 is referred to as “rear”. Also, the terms “front” and “back” shall follow the previous and subsequent definitions.

  FIG. 3 is a configuration diagram of the front-stage liquid crystal panel 122 and the rear-stage liquid crystal panel 125. Hereinafter, the front-stage liquid crystal panel 122 will be described as an example, but the same applies to the rear-stage liquid crystal panel 125.

  The front-stage liquid crystal panel 122 includes two alignment films (a first alignment film 126 and a second alignment film 127) arranged in parallel at a predetermined interval, side walls 128 and 129 surrounding four sides of the alignment film, and these The liquid crystal 130 sealed in the space between the alignment film and the side wall, the first transparent electrode 131 and the first protective glass 132 sequentially stacked on the front surface side of the first alignment film 126, and the back surface of the second alignment film 127 The second transparent electrode 133 and the second protective glass 134 are sequentially stacked on the side.

  Slits in predetermined directions (see slits 138 and 139 in FIG. 4) are formed on the surfaces of the first alignment film 126 and the second alignment film 127 in contact with the liquid crystal 130, respectively.

  Cables 135 and 136 are drawn out from the two transparent electrodes (first transparent electrode 131 and second transparent electrode 133), respectively, and the two transparent electrodes (first transparent electrode) are connected via the cables 135 and 136. 131 and the second transparent electrode 133) can be applied with a control voltage from the control unit 110. Hereinafter, the state in which the control voltage is applied is referred to as “ON” (or ON state), and the state in which the control voltage is not applied is referred to as “OFF” (or OFF state).

  The liquid crystal 130 is a liquid substance and is a special substance having regularity in molecular arrangement such as a crystal, and the shape of the liquid crystal molecules is a fine, substantially cylindrical shape (when simplified).

  The direction of the liquid crystal molecules is determined by the surface state of the alignment film at the portion in contact with the alignment film, and is determined by the direction of the adjacent liquid crystal molecules at the portion not in contact with the alignment film.

  When this is applied to FIG. 3, in the illustrated liquid crystal 130, the liquid crystal molecules in the portions in contact with the first alignment film 126 and the second alignment film 127 are oriented in the first alignment film 126 and the second alignment film, respectively. The surface state of 127, that is, the direction of the slit of the first alignment film 126 and the direction of the slit of the second alignment film 127, and the direction of the other liquid crystal molecules are determined by the direction of the adjacent liquid crystal molecules.

  FIG. 4 is a schematic diagram of the front-stage liquid crystal panel 122 and the rear-stage liquid crystal panel 125. Hereinafter, the front-stage liquid crystal panel 122 will be described as an example, but the same applies to the rear-stage liquid crystal panel 125.

  (A) shows the alignment state of the liquid crystal molecules 137 in “OFF”. The direction of the slit 138 of the first alignment film 126 and the direction of the slit 139 of the second alignment film 127 are shifted by 90 degrees.

  In the case of “OFF”, the orientations of the liquid crystal molecules 137 in contact with the first orientation film 126 and the second orientation film 127 are determined by the orientations of the slit 138 of the first orientation film 126 and the slit 139 of the second orientation film 127, respectively ( The direction of the other liquid crystal molecules 137 apart from the first alignment film 126 and the second alignment film 127 is affected by the direction of the adjacent liquid crystal molecules 137. The liquid crystal molecules 137 aligned in the thickness direction of the liquid crystal 130 are arranged in a spiral shape with a direction change of 90 degrees at the maximum while changing the direction little by little.

  (B) shows the alignment state of the liquid crystal molecules 137 in “ON”. When a required control voltage is applied between the first transparent electrode 131 and the second transparent electrode 133, the liquid crystal molecules 137 rise in the thickness direction of the liquid crystal 130 along the direction of the electric field of the control voltage and are arranged vertically.

  FIG. 5 is a schematic diagram of the light selection unit 107. The two polarizing plates (the first polarizing plate 120 and the second polarizing plate 121) of the pre-selection unit 118 are reflective polarizers that produce a polarizing function with respect to visible light (which produces polarized light from non-polarized light). It is. However, it functions as a simple transparent body for infrared light.

  In contrast, the two polarizing plates (the first polarizing plate 123 and the second polarizing plate 124) of the rear stage selection unit 119 are reflective polarizers that exhibit a polarization function with respect to infrared light. However, it functions as a simple transparent body for visible light.

  In the figure, solid double-ended arrow lines 138 to 141 represent polarized light transmission axes, and broken double-ended arrow lines 142 to 145 represent polarized light reflection axes. The directions of the solid-line double-ended arrow lines 138 to 141 and the broken-line double-ended arrow lines 142 to 145 are shifted from each other by 90 degrees (the transmission axis and the reflection axis are 90 degrees).

  Both the front-stage liquid crystal panel 122 and the rear-stage liquid crystal panel 125 constitute 90 ° TN (Twisted Nematic) liquid crystal. The value of “Δnd” (where Δn is the birefringence of the liquid crystal and d is the thickness of the liquid crystal) of the 90 ° TN liquid crystal is, for example, “near 0.48 μm” in the front-stage liquid crystal panel 122 and “ It is around 0.72 μm ”.

  FIG. 6 is a transmission and reflection characteristic diagram of the polarizing plate. In this figure, (a) shows two polarizing plates (first polarizing plate 120 and second polarizing plate 121) of the pre-selection unit 118, for example, a reflective polarizing film (DBEF: Dual Brightness Enhancement) manufactured by Sumitomo 3M Limited. The characteristics in the case of using (Film) are shown, the solid line is the visible light p-wave (transmission), and the broken line is the visible light s-wave (reflection) characteristic line. Moreover, (b) has shown the characteristic at the time of using a wire grid polarizing plate for the two polarizing plates (the 1st polarizing plate 123 and the 2nd polarizing plate 124) of the back | latter stage selection part 119, for example, the continuous line is The infrared light p-wave (transmission) and the broken line are the characteristic lines of the infrared light s-wave (reflection).

  Here, the p wave and the s wave are one of the concepts related to polarization. In other words, it is a concept defined by the “incident surface” and the “vibration direction of an electric or magnetic field” when light is reflected at a boundary surface between different materials. In optics, s-wave (or s-polarized light) and p A distinction is made between waves (or p-polarized light). When light is incident on the boundary surface, the light can be divided into an s-wave component and a p-wave component, and the overall reflectivity is [(ratio of s-wave component × s-wave reflectivity) + (p wave Component ratio × p wave reflectivity)]. The p-wave reflectivity is smaller than the s-wave at any incident angle. Such s-wave and p-wave concepts are defined only when there is an entrance surface (thus, when light enters the boundary between different materials).

  As shown to (a), the two polarizing plates (the 1st polarizing plate 120 and the 2nd polarizing plate 121) of the front | former stage selection part 118 have the high transmittance | permeability of visible p-wave in visible region, and visible light. The transmittance of the s wave is low. Moreover, as shown in (b), the two polarizing plates (the first polarizing plate 123 and the second polarizing plate 124) of the post-selection unit 119 have infrared p-wave transmittance in the infrared region. The transmittance of infrared light s-wave is low.

  Due to these characteristics, the two polarizing plates (first polarizing plate 120 and second polarizing plate 121) of the pre-selection unit 118 exhibit a polarizing function with respect to normal visible light, and with respect to infrared light. Does not exhibit the function of polarized light (functions as a simple transparent body). Further, the two polarizing plates (the first polarizing plate 123 and the second polarizing plate 124) of the post-selection unit 119 exhibit a polarizing function for infrared light and a polarizing function for visible light. No (functions just as a transparent body).

7 and 8 are diagrams illustrating four operation modes of the light selection unit 107. FIG.
(1) First operation mode [no outgoing light: FIG. 7 (a)]
As described above, the first polarizing plate 120 and the second polarizing plate 121 of the pre-selection unit 118 polarize visible light and transmit infrared light as it is. On the contrary, the first polarizing plate 123 and the second polarizing plate 124 of the rear selection unit 119 polarize infrared light and transmit visible light as it is.

  Reflected light P4 from the observation object (the affected part in the body, etc.) guided by the third light guide 115 is incident on the light selector 107, and the reflected light P4 reflects the visible light P2. A component (hereinafter, visible light component P2 ′) and a reflection component of infrared light P3 (hereinafter, infrared light component P3 ′) are included.

  When both the front-stage liquid crystal panel 122 and the rear-stage liquid crystal panel 125 are turned “OFF”, the liquid crystal molecules 137 of the front-stage liquid crystal panel 122 and the rear-stage liquid crystal panel 125 are both aligned by 90 degrees.

  In this alignment state, the visible light component P2 ′ polarized by the first polarizing plate 120 of the pre-selection unit 118 and the infrared light component P3 ′ passing through the first polarizing plate 120 first pass through the pre-liquid crystal panel 122. However, the visible light component P2 ′ is polarized by the first polarizing plate 120 of the front stage selection unit 118, and is further changed in direction by 90 degrees when passing through the front stage liquid crystal panel 122. As a result, it coincides with the direction of the reflection axis 143 (see FIG. 5) of the second polarizing plate 121 of the portion 118. All of the visible light component P <b> 2 ′ is reflected by the second polarizing plate 121 of the front stage selection unit 118 and does not pass through the front stage selection unit 118.

  On the other hand, the non-polarized infrared light component P <b> 3 ′ passes through the first polarizing plate 120, the front liquid crystal panel 122, and the second polarizing plate 121 of the front selection unit 118. Then, since the light is polarized by the first polarizing plate 123 of the rear stage selection unit 119 and further changed in direction by 90 degrees by the rear stage liquid crystal panel 125, the reflection axis 145 of the second polarizing plate 124 of the rear stage selection unit 119 (see FIG. 5). ) And the infrared light component P3 ′ is reflected by the second polarizing plate 124 of the rear stage selection unit 119 and does not pass through the rear stage selection unit 119.

  Therefore, by turning off both the front-stage liquid crystal panel 122 and the rear-stage liquid crystal panel 125, both the visible light component P2 ′ and the infrared light component P3 ′ are not extracted (not emitted) from the light selection unit 107. be able to.

(2) Second operation mode [only visible light component is emitted: FIG. 7 (b)]
When the front-stage liquid crystal panel 122 is turned “ON” and the rear-stage liquid crystal panel 125 is turned “OFF”, the liquid crystal molecules 137 of the front-stage liquid crystal panel 122 are in an upright alignment state, and the liquid crystal molecules 137 of the rear-stage liquid crystal panel 125 are shifted by 90 degrees. It will be in an alignment state.

  In this alignment state, both the visible light component P2 ′ polarized by the first polarizing plate 120 of the pre-selection unit 118 and the non-polarized infrared light component P3 ′ passing through the first polarizing plate 120 are both in the pre-stage liquid crystal panel 122. Pass through. However, the magnitude of the visible light component P2 ′ that is polarized light is almost halved.

  Next, the visible light component P2 ′ passes through the first polarizing plate 123 of the rear-stage selection unit 119, and after the direction is changed by 90 degrees by the rear-stage liquid crystal panel 125, passes through the second polarizing plate 124 of the rear-stage selection unit 119. To do.

  On the other hand, since the infrared light component P3 ′ is polarized by the first polarizing plate 123 of the rear stage selection unit 119 and further changed in direction by 90 degrees by the rear stage liquid crystal panel 125, the reflection axis of the second polarizing plate 124 of the rear stage selection unit 119. 145 (refer to FIG. 5). For this reason, the infrared component P3 ′ is reflected by the second polarizing plate 124 of the rear stage selection unit 119 and does not pass through the rear stage selection unit 119.

  Accordingly, by turning the front stage liquid crystal panel 122 “ON” and the rear stage liquid crystal panel 125 “OFF”, only the visible light component P2 ′ is selectively extracted (emitted) from the light selection unit 107 as the selection light P5. Can do.

(3) Third operation mode [only infrared light component is emitted: FIG. 8 (a)]
When the front-stage liquid crystal panel 122 is turned “OFF” and the rear-stage liquid crystal panel 125 is turned “ON”, the liquid crystal molecules 137 of the front-stage liquid crystal panel 122 are shifted by 90 degrees, and the liquid crystal molecules 137 of the rear-stage liquid crystal panel 125 are raised. It will be in an alignment state.

  In this orientation state, the visible light component P2 ′ polarized by the first polarizing plate 120 of the pre-selection unit 118 can be turned 90 degrees by the pre-stage liquid crystal panel 122. This coincides with the direction of the reflection axis 143 (see FIG. 5). For this reason, the visible light component P <b> 2 ′ is reflected by the second polarizing plate 121 of the front stage selection unit 118 and does not pass through the front stage selection unit 118.

  On the other hand, the non-polarized infrared light component P 3 ′ passes through the first polarizing plate 120, the front liquid crystal panel 122, and the second polarizing plate 121 of the front selection unit 118, and then passes through the first polarizing plate 123 of the rear selection unit 119. Although polarized, the liquid crystal molecules 137 of the rear-stage liquid crystal panel 125 are raised, so that the rear-stage liquid crystal panel 125 passes through and is further polarized by the second polarizing plate 124 of the rear-stage selection unit 119, and the size is reduced to almost half. It passes through the previous stage selection unit 118.

  Therefore, by turning off the front-stage liquid crystal panel 122 and turning on the rear-stage liquid crystal panel 125, only the infrared light component P3 ′ is selectively extracted (emitted) from the light selection unit 107 as the selection light P5. be able to.

(4) Fourth operation mode [Emission of both visible light component and infrared light component: FIG. 8 (b)]
When both the front-stage liquid crystal panel 122 and the rear-stage liquid crystal panel 125 are turned “ON”, the liquid crystal molecules 137 of the front-stage liquid crystal panel 122 and the rear-stage liquid crystal panel 125 both rise.

  In this alignment state, both the visible light component P2 ′ polarized by the first polarizing plate 120 of the pre-selection unit 118 and the non-polarized infrared light component P3 ′ passing through the first polarizing plate 120 are both in the pre-stage liquid crystal panel 122. Pass through. However, the magnitude of the visible light component P2 ′ that is polarized light is almost halved.

  Next, the visible light component P2 ′ passes through the first polarizing plate 123 of the rear stage selection unit 119, and is further turned 90 degrees by the rear stage liquid crystal panel 125, and then passes through the second polarizing plate 124 of the rear stage selection unit 119. To do.

  On the other hand, the non-polarized infrared light component P3 ′ passes through the first polarizing plate 120, the front-stage liquid crystal panel 122, and the second polarizing plate 121 of the front-stage selection unit 118, and further the first polarizing plate 123 of the rear-stage selection unit 119. However, since the liquid crystal molecules 137 of the rear-stage liquid crystal panel 125 are raised, the rear-stage liquid crystal panel 125 also passes through, and is further polarized by the second polarizing plate 124 of the rear-stage selection unit 119, and the size is almost halved. Pass through the previous stage selection unit 118.

  Therefore, by turning on both the front-stage liquid crystal panel 122 and the rear-stage liquid crystal panel 125, both the visible light component P2 ′ and the infrared light component P3 ′ are extracted (emitted) from the light selection unit 107 as the selection light P5. be able to.

  The endoscope apparatus 100 of the embodiment uses the second operation mode (emits only visible light component) and the third operation mode (emits only infrared light component) among the above four operation modes.

  FIG. 9 is a diagram illustrating an operation flow of the endoscope apparatus 100. This operation flow can be incorporated in the form of software (program) executed by a computer when the control unit 110 is configured by a program control computer. That is, since a computer is generally composed of hardware elements such as a CPU (Central Processing Unit) and a storage device for holding software executed by the CPU, the software programmed with the illustrated operation flow is stored in the storage device. The functions necessary for the operation of the endoscope apparatus 100 (particularly, the function for controlling the selection of the different wavelength light) can be realized.

  In the illustrated operation flow, first, the first light source 108 and the second light source 109 are first turned on (step S1), and then it is determined whether it is a visible image capturing timing or an infrared image capturing timing (step S1). Step S2). This capture timing is synchronized with the output period of the image frame of the imaging unit 106. For example, an odd-numbered frame period may be used as a visible image capturing timing, and an even-numbered frame period may be used as an infrared image capturing timing.

  FIG. 10 is a diagram illustrating an operation mode table. The operation mode table 140 is held in a storage device (not shown) of the control unit 110 and can be referred to from a computer of the control unit 110 as necessary.

  In the operation mode table 140, at least two operation modes of “A mode” and “B mode” and operation instruction contents of the light selection unit 107 for each mode are written. In the A mode, in order to extract only the visible light component P2 ′ as the selection light P5, the front liquid crystal panel 122 is turned “ON” and the rear liquid crystal panel 125 is turned “OFF”. In the B mode, in order to extract only the infrared light component P3 ′ as the selection light P5, the front liquid crystal panel 122 is set to “OFF” and the rear liquid crystal panel 125 is set to “ON”.

  Returning to FIG. 9 again, if it is determined that it is the timing of capturing a visible image, the light selection unit 107 is operated in the A mode (step S3).

As described above, since the A mode is a mode for extracting only the visible light component P2 ′ as the selection light P5, the visible light component P2 ′ is emitted from the light selection unit 107 operating in the A mode to the imaging unit 106. Therefore, the imaging unit 106 outputs an image (that is, a visible image) of the visible light component P2 ′.
Next, an image (in this case, a visible image) from the imaging unit 106 is taken out (step S4), the image processing unit 105 is controlled, and the visible image is output as a planar image to the first display unit 101 (step S5). Thereafter, the process returns to step S2.

  On the other hand, when it is determined that it is the timing for capturing an infrared image, the light selection unit 107 is operated in the B mode (step S6).

As described above, since the B mode is a mode in which only the infrared light component P3 ′ is extracted as the selection light P5, the infrared light component P3 ′ is transmitted from the light selection unit 107 operating in the B mode to the imaging unit 106. The imaging unit 106 outputs an image of the infrared light component P3 ′ (that is, an infrared image).
Next, an image (in this case, an infrared image) from the imaging unit 106 is extracted (step S7), the image processing unit 105 is controlled to generate a stereoscopic image from the infrared image, and the stereoscopic image is displayed on the second display. After outputting to the unit 102 (step S8), the process returns to step S2.

  As described above, the light selection unit 107 included in the endoscope apparatus 100 according to the embodiment corresponds to a “different wavelength light selection device” that selects different wavelength light (here, visible light and infrared light). And corresponds to the rotary filter (rotary filter 8 that is rotationally driven by a drive source 9 such as a motor) of the endoscope apparatus 1 (see FIG. 11) described at the beginning in that light having a different wavelength is selected. However, when the two are compared, the rotary filter or the like selects light of different wavelengths by mechanical means, whereas the light selection unit 107 of the embodiment is means other than mechanical means (optical means). Therefore, the following effects can be obtained.

  That is, the light selection unit 107 that does not include mechanical elements (and the endoscope apparatus 100 including the light selection unit 107) can reduce the size of the device, and can generate no vibration or noise. Moreover, since there are no rotating parts, mechanical wear does not occur and durability can be improved. Therefore, the object of the present invention of “contributing to downsizing of the apparatus, elimination of vibration and noise, and improvement of durability” can be achieved.

  In the above embodiment, the front-stage liquid crystal panel 122 and the rear-stage liquid crystal panel 125 are configured by 90 ° TN liquid crystal, but the present invention is not limited to this. The front-stage liquid crystal panel 122 and the rear-stage liquid crystal panel 125 may be composed of homogeneous liquid crystal (liquid crystal molecules having a homogeneous alignment) or VA (Vertical Alignment) liquid crystal. The value of “Δnd” when the liquid crystal panel is composed of homogeneous liquid crystal or VA liquid crystal is “near 0.28 μm” in the front liquid crystal panel 122 and “near 0.42 μm” in the rear liquid crystal panel 125.

  Moreover, although application to an endoscope apparatus was taken as an example in the above embodiment, the present invention is not limited to this. The present invention can be applied to various devices and systems that require selection of different wavelength light.

The features of the present invention will be described below.
A part or all of the above-described embodiment can be described as in the following supplementary notes, but is not limited thereto.
(Appendix 1)
Supplementary Note 1 is a pre-selection unit configured by sandwiching one liquid crystal panel between two polarizing plates that polarize one wavelength light and transmit two wavelength light longer than the one wavelength light;
A rear stage selection unit configured by sandwiching two liquid crystal panels between two polarizing plates that polarize the second wavelength light and transmit the one wavelength light; and
Furthermore, the different wavelength light selection device is characterized by further comprising control means for controlling a combination of ON / OFF of the one liquid crystal panel and the second liquid crystal panel.
(Appendix 2)
Appendix 2 is the different wavelength light selection device according to Appendix 1, wherein the one wavelength light is light in a visible region and the second wavelength light is light in an infrared region.
(Appendix 3)
Appendix 3 is that the control means turns on the one liquid crystal panel, turns off the second liquid crystal panel, turns off the one liquid crystal panel, and turns on the second liquid crystal panel. The different wavelength light selection device according to appendix 1 or 2, wherein the combination is controlled while switching between the two operation modes.
(Appendix 4)
Appendix 4 is that the one liquid crystal panel and the second liquid crystal panel are 90 ° TN liquid crystal, and Δnd of the one liquid crystal panel is around 0.48 μm, and Δnd of the second liquid crystal panel is around 0.72 μm. It is a different wavelength light selection apparatus in any one of the additional remarks 1 thru | or 3 characterized by these.
(Appendix 5)
Note 5 is that the one liquid crystal panel and the second liquid crystal panel are homogeneous liquid crystal or VA liquid crystal, and Δnd of the one liquid crystal panel is around 0.28 μm, and Δnd of the second liquid crystal panel is 0.42 μm. 4. The different wavelength light selecting device according to any one of appendices 1 to 3, characterized by being in the vicinity.
(Appendix 6)
Appendix 6 is an endoscope apparatus using the different wavelength light selection device according to any one of Appendixes 1 to 5.

107 light selector (different wavelength light selector)
110 Control unit (control means)
118 First-stage selection unit 119 Second-stage selection unit 120 First polarizing plate (polarizing plate)
121 Second polarizing plate (polarizing plate)
122 Front LCD panel (One LCD panel)
123 First polarizing plate (polarizing plate)
124 Second polarizing plate (polarizing plate)
125 Rear LCD panel (second LCD panel)

Claims (6)

A pre-selection unit configured to sandwich one liquid crystal panel between two polarizing plates that polarize one wavelength light and transmit two wavelength light longer than the one wavelength light;
A rear stage selection unit configured by sandwiching two liquid crystal panels between two polarizing plates that polarize the second wavelength light and transmit the one wavelength light; and
Furthermore, the different wavelength light selection apparatus provided with the control means which controls the combination of ON / OFF of said 1 liquid crystal panel and said 2nd liquid crystal panel.   2. The different wavelength light selection apparatus according to claim 1, wherein the one wavelength light is light in a visible region, and the second wavelength light is light in an infrared region.   The control means has one operation mode for turning on the one liquid crystal panel and turning off the second liquid crystal panel, and two operations for turning off the one liquid crystal panel and turning on the two liquid crystal panels. The different wavelength light selection device according to claim 1, wherein the combination is controlled while switching between modes.   The one liquid crystal panel and the second liquid crystal panel are 90 ° TN liquid crystal, and Δnd of the one liquid crystal panel is around 0.48 μm, and Δnd of the second liquid crystal panel is around 0.72 μm. The different wavelength light selection device according to claim 1, wherein:   The one liquid crystal panel and the second liquid crystal panel are homogeneous liquid crystal or VA liquid crystal, and Δnd of the first liquid crystal panel is around 0.28 μm, and Δnd of the second liquid crystal panel is around 0.42 μm. The different wavelength light selection apparatus according to claim 1, wherein:   An endoscope apparatus using the different wavelength light selector according to any one of claims 1 to 5.

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